WorldWideScience

Sample records for radiation air model

  1. An approximate local thermodynamic nonequilibrium radiation model for air

    Science.gov (United States)

    Gally, Thomas A.; Carlson, Leland A.

    1992-01-01

    A radiatively coupled viscous shock layer analysis program which includes chemical and thermal nonequilibrium is used to calculate stagnation point flow profiles for typical aeroassisted orbital transfer vehicle conditions. Two methods of predicting local thermodynamic nonequilibrium radiation effects are used as a first and second order approximation to this phenomena. Tabulated results for both nitrogen and air freestreams are given with temperature, species, and radiation profiles for some air conditions. Two body solution results are shown for 45 and 60 degree hyperboloid bodies at 12 km/sec and 80 km altitude. The presented results constitute an advancement in the engineering modeling of radiating nonequilibrium reentry flows.

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

    Science.gov (United States)

    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.

  3. Modelling geo-magnetic radiation from extensive air showers

    International Nuclear Information System (INIS)

    An incoming ultra high energy cosmic ray (UHECR) entering our atmosphere will create a so called extensive air shower (EAS). A cascade of particles flying toward the Earth's surface with extremely high velocities. As a result of this they are concentrated in a thin shower front, which can be visualized by a pancake of particles flying toward the Earth. The deflection of electrons and positrons due to the Earth magnetic field in combination with retardation effects is responsible for an electromagnetic pulse to be emitted within the radio frequency range. Concentrating on a macroscopic description, focussing on the net current created due to the deflection of the electrons and positrons in the Earth magnetic field, a model has been made to simulate the radio signal for a realistic air shower. Several different contributions to the electric pulse have been included to obtain more realistic simulations and have a better comparison with measured data.

  4. Advances in Atmospheric Radiation Measurements and Modeling Needed to Improve Air Safety

    Science.gov (United States)

    Tobiska, W. Kent; Atwell, William; Beck, Peter; Benton, Eric; Copeland, Kyle; Dyer, Clive; Gersey, Brad; Getley, Ian; Hands, Alex; Holland, Michael; Hong, Sunhak; Hwang, Junga; Jones, Bryn; Malone, Kathleen; Meier, Matthias M.; Mertens, Chris; Phillips, Tony; Ryden, Keith; Schwadron, Nathan; Wender, Stephen A.; Wilkins, Richard; Xapsos, Michael A.

    2015-04-01

    Air safety is tied to the phenomenon of ionizing radiation from space weather, primarily from galactic cosmic rays but also from solar energetic particles. A global framework for addressing radiation issues in this environment has been constructed, but more must be done at international and national levels. Health consequences from atmospheric radiation exposure are likely to exist. In addition, severe solar radiation events may cause economic consequences in the international aviation community due to exposure limits being reached by some crew members. Impacts from a radiation environment upon avionics from high-energy particles and low-energy, thermalized neutrons are now recognized as an area of active interest. A broad community recognizes that there are a number of mitigation paths that can be taken relative to the human tissue and avionics exposure risks. These include developing active monitoring and measurement programs as well as improving scientific modeling capabilities that can eventually be turned into operations. A number of roadblocks to risk mitigation still exist, such as effective pilot training programs as well as monitoring, measuring, and regulatory measures. An active international effort toward observing the weather of atmospheric radiation must occur to make progress in mitigating radiation exposure risks. Stakeholders in this process include standard-making bodies, scientific organizations, regulatory organizations, air traffic management systems, aircraft owners and operators, pilots and crew, and even the public.

  5. Computational model of collisional-radiative nonequilibrium plasma in an air-driven type laser propulsion

    International Nuclear Information System (INIS)

    A thrust power of a gas-driven laser-propulsion system is obtained through interaction with a propellant gas heated by a laser energy. Therefore, understanding the nonequilibrium nature of laser-produced plasma is essential for increasing available thrust force and for improving energy conversion efficiency from a laser to a propellant gas. In this work, a time-dependent collisional-radiative model for air plasma has been developed to study the effects of nonequilibrium atomic and molecular processes on population densities for an air-driven type laser propulsion. Many elementary processes are considered in the number density range of 1012/cm3?N?1019/cm3 and the temperature range of 300 K?T?40,000 K. We then compute the unsteady nature of pulsively heated air plasma. When the ionization relaxation time is the same order as the time scale of a heating pulse, the effects of unsteady ionization are important for estimating air plasma states. From parametric computations, we determine the appropriate conditions for the collisional-radiative steady state, local thermodynamic equilibrium, and corona equilibrium models in that density and temperature range.

  6. A new dynamical atmospheric ionizing radiation (AIR) model for epidemiological studies

    Science.gov (United States)

    De Angelis, G.; Clem, J. M.; Goldhagen, P. E.; Wilson, J. W.

    2003-01-01

    A new Atmospheric Ionizing Radiation (AIR) model is currently being developed for use in radiation dose evaluation in epidemiological studies targeted to atmospheric flight personnel such as civilian airlines crewmembers. The model will allow computing values for biologically relevant parameters, e.g. dose equivalent and effective dose, for individual flights from 1945. Each flight is described by its actual three dimensional flight profile, i.e. geographic coordinates and altitudes varying with time. Solar modulated primary particles are filtered with a new analytical fully angular dependent geomagnetic cut off rigidity model, as a function of latitude, longitude, arrival direction, altitude and time. The particle transport results have been obtained with a technique based on the three-dimensional Monte Carlo transport code FLUKA, with a special procedure to deal with HZE particles. Particle fluxes are transformed into dose-related quantities and then integrated all along the flight path to obtain the overall flight dose. Preliminary validations of the particle transport technique using data from the AIR Project ER-2 flight campaign of measurements are encouraging. Future efforts will deal with modeling of the effects of the aircraft structure as well as inclusion of solar particle events. Published by Elsevier Ltd on behalf of COSPAR.

  7. An improved mathematical model for prediction of air quantity to minimise radiation levels in underground uranium mines

    International Nuclear Information System (INIS)

    Ventilation is the primary means of controlling radon and its daughter concentrations in an underground uranium mine environment. Therefore, prediction of air quantity is the vital component for planning and designing of ventilation systems to minimise the radiation exposure of miners in underground uranium mines. This paper comprehensively describes the derivation and verification of an improved mathematical model for prediction of air quantity, based on the growth of radon daughters in terms of potential alpha energy concentration (PAEC), to reduce the radiation levels in uranium mines. The model also explains the prediction of air quantity depending upon the quality of intake air to the stopes. This model can be used to evaluate the contribution of different sources to radon concentration in mine atmosphere based on the measurements of radon emanation and exhalation. Moreover, a mathematical relationship has been established for quick prediction of air quantity to achieve the desired radon daughter concentration in the mines. - Highlights: • Proposed an improved model to predict air quantity for underground uranium mines. • The model predicts the air quantity depending on the quality of intake air to the stope. • The model will be useful for designing ventilation systems of underground uranium mines. • The mathematical model was used to identify the main sources of radon in mine air. • Established a relationship between air quantity and potential alpha energy concentration

  8. Air pollution and climate response to aerosol direct radiative effects: A modeling study of decadal trends across the northern hemisphere

    Science.gov (United States)

    Decadal hemispheric Weather Research and Forecast-Community Multiscale Air Quality simulations from 1990 to 2010 were conducted to examine the meteorology and air quality responses to the aerosol direct radiative effects. The model's performance for the simulation of hourly surfa...

  9. An improved mathematical model for prediction of air quantity to minimise radiation levels in underground uranium mines.

    Science.gov (United States)

    Panigrahi, Durga Charan; Sahu, Patitapaban; Mishra, Devi Prasad

    2015-02-01

    Ventilation is the primary means of controlling radon and its daughter concentrations in an underground uranium mine environment. Therefore, prediction of air quantity is the vital component for planning and designing of ventilation systems to minimise the radiation exposure of miners in underground uranium mines. This paper comprehensively describes the derivation and verification of an improved mathematical model for prediction of air quantity, based on the growth of radon daughters in terms of potential alpha energy concentration (PAEC), to reduce the radiation levels in uranium mines. The model also explains the prediction of air quantity depending upon the quality of intake air to the stopes. This model can be used to evaluate the contribution of different sources to radon concentration in mine atmosphere based on the measurements of radon emanation and exhalation. Moreover, a mathematical relationship has been established for quick prediction of air quantity to achieve the desired radon daughter concentration in the mines. PMID:25461521

  10. Simulation of an ethylene-air jet flame with soot and radiation modeling

    Science.gov (United States)

    Doom, Jeffrey; Oefelein, Joseph

    2009-11-01

    Large eddy simulation of an ethylene-air diffusion flame and supporting direct numerical simulations are presented. A reduced mechanism recently developed by Wang et al. is used (22 species, 107 reactions) and a systematic study is performed which compares the reduced mechanism to the original full mechanism (USC Mech Version II: 111 species, 784 reactions). A series of calculations are then validated by comparing results with CHEMKIN, Lignell et al. (Combust. Flame 2007) and the premixed experiments from Bhargava & Westmoreland (Combust. Flame 1998). The baseline soot model employed is from Leung et al (Combust. Flame 1991) and accounts for nucleation, growth, oxidation and coagulation. This model is coupled through source terms as a function of C2H2, C O, O2 and H2. The first two moments are considered to account for the number density and soot mass per volume. Initially the radiation model assumes an optically thin medium in a manner consistent with Lignell et al. Results associated with the soot model will be presented along with comparisons with experimental data.

  11. Radiation Effects Investigations Based on Atmospheric Radiation Model (ATMORAD) Considering GEANT4 Simulations of Extensive Air Showers and Solar Modulation Potential.

    Science.gov (United States)

    Hubert, Guillaume; Cheminet, Adrien

    2015-07-01

    The natural radiative atmospheric environment is composed of secondary cosmic rays produced when primary cosmic rays hit the atmosphere. Understanding atmospheric radiations and their dynamics is essential for evaluating single event effects, so that radiation risks in aviation and the space environment (space weather) can be assessed. In this article, we present an atmospheric radiation model, named ATMORAD (Atmospheric Radiation), which is based on GEANT4 simulations of extensive air showers according to primary spectra that depend only on the solar modulation potential (force-field approximation). Based on neutron spectrometry, solar modulation potential can be deduced using neutron spectrometer measurements and ATMORAD. Some comparisons between our methodology and standard approaches or measurements are also discussed. This work demonstrates the potential for using simulations of extensive air showers and neutron spectroscopy to monitor solar activity. PMID:26151172

  12. Vibrational and electronic collisional-radiative model in air for Earth entry problems

    Energy Technology Data Exchange (ETDEWEB)

    Annaloro, Julien, E-mail: Julien.Annaloro@cnes.fr [CNES, 18 Avenue Edouard Belin, 31401 Toulouse Cedex 9 (France); CORIA - UMR 6614, Normandie Universit, CNRS - Universit et INSA de Rouen, Campus Universitaire du Madrillet, 76800 Saint-Etienne du Rouvray Cedex (France); Bultel, Arnaud, E-mail: Arnaud.Bultel@coria.fr [CORIA - UMR 6614, Normandie Universit, CNRS - Universit et INSA de Rouen, Campus Universitaire du Madrillet, 76800 Saint-Etienne du Rouvray Cedex (France)

    2014-12-15

    The two-temperature collisional-radiative model CoRaM-AIR, working over a wide range for pressure and temperatures, has been developed for the flow conditions around a space vehicle entering the Earth's atmosphere. The species N{sub 2}, O{sub 2}, NO, N, O, Ar, N{sub 2}{sup +}, O{sub 2}{sup +}, NO{sup +}, N{sup +}, O{sup +}, Ar{sup +}, and free electrons are taken into account. The model is vibrationally specific on the ground electronic state of N{sub 2}, O{sub 2}, and NO, and electronically specific for all species, with a total of 169 vibrational states and 829 electronic states, respectively. A wide set of elementary processes is considered under electron and heavy particle impact given the temperatures involved (up to 30?000?K). This set corresponds to almost 700?000 forward and backward elementary processes. The relaxation from initial thermal or chemical nonequilibrium is studied for dissociation-ionization situations in conditions related to the FIRE II flight experiment. Boltzmann plots clearly prove that the vibrational and electronic excitation distributions are far from being Boltzmanian. In particular, high-lying vibrational levels remain underpopulated for most of the duration of the relaxation. This relaxation can be separated in a first phase characterized by the dissociation and the excitation of the molecular species, and a second phase leading to the excitation and the ionization of the dissociation products. Owing to the vibrational relaxation, the time scales are slightly higher than the ones predicted by former kinetic mechanisms usually used in flow simulations. In the present FIRE II conditions, radiation does not play a significant role.

  13. Vibrational and electronic collisional-radiative model in air for Earth entry problems

    International Nuclear Information System (INIS)

    The two-temperature collisional-radiative model CoRaM-AIR, working over a wide range for pressure and temperatures, has been developed for the flow conditions around a space vehicle entering the Earth's atmosphere. The species N2, O2, NO, N, O, Ar, N2+, O2+, NO+, N+, O+, Ar+, and free electrons are taken into account. The model is vibrationally specific on the ground electronic state of N2, O2, and NO, and electronically specific for all species, with a total of 169 vibrational states and 829 electronic states, respectively. A wide set of elementary processes is considered under electron and heavy particle impact given the temperatures involved (up to 30 000 K). This set corresponds to almost 700 000 forward and backward elementary processes. The relaxation from initial thermal or chemical nonequilibrium is studied for dissociation-ionization situations in conditions related to the FIRE II flight experiment. Boltzmann plots clearly prove that the vibrational and electronic excitation distributions are far from being Boltzmanian. In particular, high-lying vibrational levels remain underpopulated for most of the duration of the relaxation. This relaxation can be separated in a first phase characterized by the dissociation and the excitation of the molecular species, and a second phase leading to the excitation and the ionization of the dissociation products. Owing to the vibrational relaxation, the time scales are slightly higher than the ones predicted by former kinetic mechanisms usually used in flow simulations. In the present FIRE II conditions, radiation does not play a significant role

  14. Air pollution and climate response to aerosol direct radiative effects: A modeling study of decadal trends across the northern hemisphere

    Science.gov (United States)

    Xing, Jia; Mathur, Rohit; Pleim, Jonathan; Hogrefe, Christian; Gan, Chuen-Meei; Wong, David C.; Wei, Chao; Wang, Jiandong

    2015-12-01

    Decadal hemispheric Weather Research and Forecast-Community Multiscale Air Quality simulations from 1990 to 2010 were conducted to examine the meteorology and air quality responses to the aerosol direct radiative effects. The model's performance for the simulation of hourly surface temperature, relative humidity, wind speed, and direction was evaluated through comparison with observations from NOAA's National Climatic Data Center Integrated Surface Data. The inclusion of aerosol direct radiative effects improves the model's ability to reproduce the trend in daytime temperature range which over the past two decades was increasing in eastern China but decreasing in eastern U.S. and Europe. Trends and spatial and diurnal variations of the surface-level gaseous and particle concentrations to the aerosol direct effect were analyzed. The inclusion of aerosol direct radiative effects was found to increase the surface-level concentrations of SO2, NO2, O3, SO42-, NO3-, and particulate matter 2.5 in eastern China, eastern U.S., and Europe by 1.5-2.1%, 1-1.5%, 0.1-0.3%, 1.6-2.3%, 3.5-10.0%, and 2.2-3.2%, respectively, on average over the entire 21 year period. However, greater impacts are noted during polluted days with increases of 7.6-10.6%, 6.2-6.7%, 2.0-3.0%, 7.8-9.5%, 11.1-18.6%, and 7.2-10.1%, respectively. Due to the aerosol direct radiative effects, stabilizing of the atmosphere associated with reduced planetary boundary layer height and ventilation leads to an enhancement of pollution. Consequently, the continual increase of aerosol optical depth (AOD) in eastern China leads to an increasing trend in the air quality feedback which exacerbates air pollution, while emission reductions in eastern U.S. and Europe result in a declining trend in both AODs and feedback which make the air pollution control strategies more effective.

  15. Sensitivity of modelled sulfate radiative forcing to DMS concentration and air-sea flux formulation

    Science.gov (United States)

    Tesdal, J.-E.; Christian, J. R.; Monahan, A. H.; von Salzen, K.

    2015-09-01

    In this study, we use an atmospheric general circulation model with explicit aerosol chemistry (CanAM4.1) and several climatologies of surface ocean DMS concentration to assess uncertainties about the climate impact of ocean DMS efflux. Despite substantial variation in the spatial pattern and seasonal evolution of simulated DMS fluxes, the global mean radiative forcing is approximately linearly proportional to the global mean surface flux of DMS; the spatial and temporal distribution of ocean DMS efflux has only a minor effect on the global radiation balance. The effect of the spatial structure, however, generates statistically significant changes in the global mean concentrations of some aerosol species. The effect of seasonality on net radiative forcing is larger than that of spatial distribution, and is significant at global scale.

  16. Modelling diurnal patterns of air temperature, radiation, wind speed and relative humidity by equations from daily characteristics

    International Nuclear Information System (INIS)

    Calculated data on diurnal patterns from daily averages can be useful as inputs for models simulating plant processes such as photosynthesis and transpiration. A method was developed for the calculation of diurnal patterns of air temperature, wind speed, global radiation and relative humidity from available daily data. Calculated data were validated with measured data collected in Israel, California and The Netherlands. A simple sine-exponential method for describing diurnal air temperature was not sufficient in most cases, and the addition of parameters which specified the time lag of maximum temperature and the effect of buoyancy improved the data accuracy. Diurnal course of wind speed could be described using two sine curves scaled by the measured daily total wind run. Time base of each of the sine curves and the minimum wind speed had to be defined for each location. An accurate description of the diurnal global radiation was obtained, based on the measured daily total global radiation, and the calculated sine of the solar elevation corrected for atmospheric transmissivity. Relative humidity was calculated from the dew point temperature computed as the minimum value of a characteristic seasonal value or the actual air temperature. When the site-specific parameters were known or correctly estimated these methods gave good estimations of the diurnal weather patterns. (author)

  17. Non-Boltzmann Modeling for Air Shock-Layer Radiation at Lunar-Return Conditions

    Science.gov (United States)

    Johnston, Christopher O.; Hollis, Brian R.; Sutton, Kenneth

    2008-01-01

    This paper investigates the non-Boltzmann modeling of the radiating atomic and molecular electronic states present in lunar-return shock-layers. The Master Equation is derived for a general atom or molecule while accounting for a variety of excitation and de-excitation mechanisms. A new set of electronic-impact excitation rates is compiled for N, O, and N2+, which are the main radiating species for most lunar-return shock-layers. Based on these new rates, a novel approach of curve-fitting the non-Boltzmann populations of the radiating atomic and molecular states is developed. This new approach provides a simple and accurate method for calculating the atomic and molecular non-Boltzmann populations while avoiding the matrix inversion procedure required for the detailed solution of the Master Equation. The radiative flux values predicted by the present detailed non-Boltzmann model and the approximate curve-fitting approach are shown to agree within 5% for the Fire 1634 s case.

  18. Sensitivity of modelled sulfate radiative forcing to DMS concentration and air-sea flux formulation

    OpenAIRE

    J.-E. Tesdal; J. R. Christian; Monahan, A. H.; Von Salzen, K

    2015-01-01

    In this study, we use an atmospheric general circulation model with explicit aerosol chemistry (CanAM4.1) and several climatologies of surface ocean DMS concentration to assess uncertainties about the climate impact of ocean DMS efflux. Despite substantial variation in the spatial pattern and seasonal evolution of simulated DMS fluxes, the global mean radiative forcing is approximately linearly proportional to the global mean surface flux of DMS; the spatial and temporal dis...

  19. Assessing the transferability of support vector machine model for estimation of global solar radiation from air temperature

    International Nuclear Information System (INIS)

    Highlights: • Transferability of SVM in estimation of solar radiation is investigated. • Radiation at estimation site could be well estimated by SVM developed at source site. • A strategy for selecting a suitable source site is presented. • SVM accuracy is affected by distance and temperature difference between two sites. • RMSE of SVM shows logarithm or linearly relationship with altitude of source site. - Abstract: Exploring novel methods for estimation of global solar radiation from air temperature has been being a focus in many studies. This paper evaluates the transferability of support vector machines (SVM) for estimation of solar radiation in subtropical zone in China. Results suggest that solar radiation at one site (estimation site) could be well estimated by SVM model developed at another site (source site). The accuracy of estimation is affected by the distance and temperature difference between two sites, and altitude of source site. Higher correlations between RMSE of SVM and distance, and temperature differences are observed in northeastern region, increasing the reliability and confidence of SVM model developed at nearby stations. While lower correlations between RMSE and distance, and temperature differences are observed in southwest plateau region. When the altitude of estimation site is lower than 1200 m, RMSE show logarithm relationship with altitude of source sites where the altitude are lower than that of estimation site. Otherwise, RMSE show linearly relationship with altitude of source sites where the altitude are higher than 200 m but lower than that of the estimation site. This result suggests that solar radiation could be also estimated using SVM model developed at the site with similar but lower altitude. Based on these results, a strategy that takes into account the climatic conditions, topography, distance, and altitude for selecting a suitable source site is presented. The findings can guide and ease the appropriate choice of source sites for estimation of solar radiation at estimation site

  20. A simple model to estimate radiation doses to aircrew during air flights in Brazil and abroad

    International Nuclear Information System (INIS)

    The objective of this article is to present the results obtained from the development of a simple model used to estimate cosmic radiation doses from crew members taking into consideration the variation of the dose rates with the altitude and the latitude, airplane cruise velocity and other important parameters such as, cruise height, takeoff time, landing time, takeoff angle, landing angle. The model was incorporated into a Brazilian computer program developed using the “mathematica” symbolic software. The data used to calculate the dose rates with altitude and latitude by the authors takes into consideration the mean solar activity from January 1958 to December 2008 (51 years). Twenty two data including international and national American flights were used to test the program and the results between them compared, showing good agreement. The program also gives excellent results for the doses expected for the crew members of three Brazilian national flights (between capitals cities in Brazil) when compared with the doses values measured for these flights using a radiation detector. According to the results the doses expected for the Brazilian crews of domestic flights can, in some cases, depending on the number of annual flights, overcome the limit of 1 mSv/year established by the Brazilian competent authority in Brazil (Brazilian Nuclear Energy Commission- CNEN) for public annual exposure. In the case of the simulated international flights the results shows a good agreement with the results found in literature especially when considered the different database series used by the authors and by the other references for the solar activity. (authors)

  1. Preliminary validation of computational procedures for a new atmospheric ionizing radiation (AIR) model.

    Science.gov (United States)

    Clem, John M; De Angelis, Giovanni; Goldhagen, Paul; Wilson, John W

    2003-01-01

    A new computational procedure to determine particle fluxes in the Earth's atmosphere is presented. The primary cosmic ray spectrum has been modeled through an analysis of simultaneous proton and helium measurements made on high altitude balloon flights and spacecraft. An improved global fit to the data was achieved through applying a unique technique utilizing the Fokker-Plank equation with a non-linear rigidity-dependent diffusion coefficient. The propagation of primary particles through the Earth's atmosphere is calculated with a three-dimensional Monte Carlo transport program called FLUKA. Primary protons and helium nuclei (alphas) are generated within the rigidity range of 0.5 GV-20 TV uniform in cos2 theta. For a given location, primaries above the effective cutoff rigidity are transported through the atmosphere. Alpha particles are initially transported with a separate package called HEAVY to simulate fragmentation. This package interfaces with FLUKA to provide interaction starting points for each nucleon originating from a helium nucleus. Results from this calculation are presented and compared to measurements. PMID:14727659

  2. A female pelvic bone shape model for air/bone separation in support of synthetic CT generation for radiation therapy

    Science.gov (United States)

    Liu, Lianli; Cao, Yue; Fessler, Jeffrey A.; Jolly, Shruti; Balter, James M.

    2016-01-01

    Separating bone from air in MR data is one of the major challenges in using MR images to derive synthetic CT. The problem is further complicated when the anatomic regions filled with air are altered across scans due to air mobility, for instance, in pelvic regions, thereby the air regions estimated using an ultrashort echo time (UTE) sequence are invalid in other image series acquired for multispectral classification. This study aims to develop and investigate a female pelvic bone shape model to identify low intensity regions in MRI where air is unlikely to be present in support of synthetic CT generation without UTE imaging. CT scans of 30 patients were collected for the study, 17 of them also have corresponding MR scans. The shape model was built from the CT dataset, where the reference image was aligned to each of the training images using B-spline deformable registration. Principal component analysis was performed on B-spline coefficients for a compact model where shape variance was described by linear combination of principal modes. The model was applied to identify pelvic bone in MR images by deforming the corresponding MR data of the reference image to target MR images, where the search space of the deformation process was constrained within the subspace spanned by principal modes. The local minima in the search space were removed effectively by the shape model, thus supporting an efficient binary search for the optimal solution. We evaluated the model by its efficacy in identifying bone voxels and excluding air regions. The model was tested across the 17 patients that have corresponding MR scans using a leave-one-out cross validation. A simple model using the first leading principal mode only was found to achieve reasonable accuracy, where an averaged 87% of bone voxels were correctly identified. Finally dilation of the optimally fit bone mask by 5 mm was found to cover 96% of bone voxels while minimally impacting the overlap with air (below 0.4%).

  3. SESAM - a model for calculating the radiation exposure associated with the release of pollutants contained in the exhaust air in the case of a multi-source situation

    International Nuclear Information System (INIS)

    Within the scope of the research project St.Sch.645, sponsored by the German Federal Minister of Research and Technology (BMFT) a model and computer code called SESAM (calculation of radiation exposure by release of pollutants with the exhaust air in the case of a multi-source situation) was established, allowing to perform all the assessments of long-time exposure required for licensing - as e.g. evaluation of the maximum individual radiation exposure of the different organs at the most unfavorable point of reference - associated with the environmental impact of several nuclear sources of release - as e.g. several units of a nuclear power plant, different sources of a waste management center, or also consideration of the pre-existing exposures of a site caused by nuclear sources. The basis of this multi-source model SESAM are the models for calculating the exposure in the environment of nuclear facilities for the pathways external gamma radiation from the cloud, external beta radiation from the cloud, gamma radiation from material deposited on the ground, inhalation and ingestion, as well as the data material, as e.g. dose constants and radioecological conversion factors (kg 1 and kg 2) for critical groups of the popualation, specified in the German guideline Principles for Calculating the Exposure Caused by the Release of Radioactive Material with the Exhaust Air. (orig./HP)

  4. New combined models for estimating daily global solar radiation from measured air temperature in semi-arid climates: Application in Ghardaïa, Algeria

    International Nuclear Information System (INIS)

    Highlights: • New combined models been introduced for estimating daily global solar radiation. • The BNN is the most accurate model compared with combined models. • Results indicate that the new calibrated models are able to estimate the global solar. - Abstract: In this paper, combined empirical models and a Bayesian neural network (BNN) model have been developed to estimate daily global solar radiation (GSR) on a horizontal surface in Ghardaïa, Algeria. An experimental database of daily GSR, maximum and minimum air temperatures of the year 2006 has been used to estimate the coefficients of the empirical models, as well as to train the BNN model. Six months of the year 2007 (summer period: May, June, July, and winter period: October, November, December) have been used to test the calibrated models, while six months of the year 2012 (from 1st February to 31th July) have been used to check generalisation capability of the developed models as well as the BNN model. Results indicate that the new calibrated models are able to estimate the global solar radiation with an excellent accuracy in this location. Calibrated models are also compared with the developed BNN model to show their effectiveness

  5. A female pelvic bone shape model for air/bone separation in support of synthetic CT generation for radiation therapy.

    Science.gov (United States)

    Liu, Lianli; Cao, Yue; Fessler, Jeffrey A; Jolly, Shruti; Balter, James M

    2016-01-01

    Separating bone from air in MR data is one of the major challenges in using MR images to derive synthetic CT. The problem is further complicated when the anatomic regions filled with air are altered across scans due to air mobility, for instance, in pelvic regions, thereby the air regions estimated using an ultrashort echo time (UTE) sequence are invalid in other image series acquired for multispectral classification. This study aims to develop and investigate a female pelvic bone shape model to identify low intensity regions in MRI where air is unlikely to be present in support of synthetic CT generation without UTE imaging. CT scans of 30 patients were collected for the study, 17 of them also have corresponding MR scans. The shape model was built from the CT dataset, where the reference image was aligned to each of the training images using B-spline deformable registration. Principal component analysis was performed on B-spline coefficients for a compact model where shape variance was described by linear combination of principal modes. The model was applied to identify pelvic bone in MR images by deforming the corresponding MR data of the reference image to target MR images, where the search space of the deformation process was constrained within the subspace spanned by principal modes. The local minima in the search space were removed effectively by the shape model, thus supporting an efficient binary search for the optimal solution. We evaluated the model by its efficacy in identifying bone voxels and excluding air regions. The model was tested across the 17 patients that have corresponding MR scans using a leave-one-out cross validation. A simple model using the first leading principal mode only was found to achieve reasonable accuracy, where an averaged 87% of bone voxels were correctly identified. Finally dilation of the optimally fit bone mask by 5 mm was found to cover 96% of bone voxels while minimally impacting the overlap with air (below 0.4%). PMID:26624989

  6. Extension of radiative transfer code MOMO, matrix-operator model to the thermal infrared – Clear air validation by comparison to RTTOV and application to CALIPSO-IIR

    International Nuclear Information System (INIS)

    1-D radiative transfer code Matrix-Operator Model (MOMO), has been extended from [0.2−3.65μm] the band to the whole [0.2−100μm] spectrum. MOMO can now be used for the computation of a full range of radiation budgets (shortwave and longwave). This extension to the longwave part of the electromagnetic radiation required to consider radiative transfer processes that are features of the thermal infrared: the spectroscopy of the water vapor self- and foreign-continuum of absorption at 12μm and the emission of radiation by gases, aerosol, clouds and surface. MOMO's spectroscopy module, Coefficient of Gas Absorption (CGASA), has been developed for computation of gas extinction coefficients, considering continua and spectral line absorptions. The spectral dependences of gas emission/absorption coefficients and of Planck's function are treated using a k-distribution. The emission of radiation is implemented in the adding–doubling process of the matrix operator method using Schwarzschild's approach in the radiative transfer equation (a pure absorbing/emitting medium, namely without scattering). Within the layer, the Planck-function is assumed to have an exponential dependence on the optical-depth. In this paper, validation tests are presented for clear air case studies: comparisons to the analytical solution of a monochromatic Schwarzschild's case without scattering show an error of less than 0.07% for a realistic atmosphere with an optical depth and a blackbody temperature that decrease linearly with altitude. Comparisons to radiative transfer code RTTOV are presented for simulations of top of atmosphere brightness temperature for channels of the space-borne instrument MODIS. Results show an agreement varying from 0.1 K to less than 1 K depending on the channel. Finally MOMO results are compared to CALIPSO Infrared Imager Radiometer (IIR) measurements for clear air cases. A good agreement was found between computed and observed radiance: biases are smaller than 0.5 K and Root Mean Square Error (RMSE) varies between 0.4 K and 0.6 K depending on the channel. The extension of the code allows the utilization of MOMO as forward model for remote sensing algorithms in the full range spectrum. Another application is full range radiation budget computations (heating rates or forcings). - Highlights: • We present the extension of radiative transfer code MOMO, Matrix operator Model, to the thermal infrared. • The emission of radiation by gases, aerosols and clouds is implemented in the matrix operator algorithm. • A spectroscopy code named CGASA is integrated and simulates the water vapor continuum of absorption. • The validation is done by comparisons to CALIPSO-IIR measurements and to simulations with RTTOV

  7. Air and radiation monitoring stations

    CERN Multimedia

    AUTHOR|(SzGeCERN)582709

    2015-01-01

    CERN has around 100 monitoring stations on and around its sites. New radiation measuring stations, capable of detecting even lower levels of radiation, were installed in 2014. Two members of HE-SEE group (Safety Engineering and Environment group) in front of one of the new monitoring stations.

  8. SESAM: a model for the calculation of radiation exposure by emission of pollutants with the exhaust air in the case of a multi-source situation

    International Nuclear Information System (INIS)

    The report deals with the calculation of the individual radiation exposure in the catchment area of several nuclear emitters. A model and computer program, SESAM - Calculation of the Radiation Exposure by Emission of Pollutants with the Exhaust air in the Case of a Multi-Source Situation -, was developed which makes possible all the evaluations of long-time exposure which are relevant for the licensing process - such as the determination of the maximum individual radiation exposure to the various organs at the worst receiving point - together with the exposure of the environment by several nuclear emission sources - such as, for example, several units of a power plant facility, the various emitters of a waste management center, or even consideration of the previous exposure of a site by nuclear emission sources

  9. A general model for estimation of daily global solar radiation using air temperatures and site geographic parameters in Southwest China

    Science.gov (United States)

    Li, Mao-Fen; Fan, Li; Liu, Hong-Bin; Guo, Peng-Tao; Wu, Wei

    2013-01-01

    Estimation of daily global solar radiation (Rs) from routinely measured temperature data has been widely developed and used in many different areas of the world. However, many of them are site specific. It is assumed that a general model for estimating daily Rs using temperature variables and geographical parameters could be achieved within a climatic region. This paper made an attempt to develop a general model to estimate daily Rs using routinely measured temperature data (maximum (Tmax, °C) and minimum (Tmin, °C) temperatures) and site geographical parameters (latitude (La, °N), longitude (Ld, °E) and altitude (Alt, m)) for Guizhou and Sichuan basin of southwest China, which was classified into the hot summer and cold winter climate zone. Comparison analysis was carried out through statistics indicators such as root mean squared error of percentage (RMSE%), modeling efficiency (ME), coefficient of residual mass (CRM) and mean bias error (MBE). Site-dependent daily Rs estimating models were calibrated and validated using long-term observed weather data. A general formula was then obtained from site geographical parameters and the better fit site-dependent models with mean RMSE% of 38.68%, mean MBE of 0.381 MJ m-2 d-1, mean CRM of 0.04 and mean ME value of 0.713.

  10. Early radiation warning system for air radioactivity

    International Nuclear Information System (INIS)

    The Austrian Research Centre Seibersdorf has developed the HYDRODAT-S (Stationary) data-logger and the SSM-1 stationary radiation protection survey meter. In connection with sensors for the measurement of meteorological data, the two systems can be combined to stations for early radiation warning, which are suitable for extension into networks together with a host computer. One measuring station consists of the sensors, one SSM-1 radiation protection survey meter and one HYDRODAT-S data-logger. The sensors are installed on an open-air site. With the exception of sensor heating, a solar power plant with buffer battery can be used for power generation. All hardware units are built in energy-saving CMOS technique, without mechanically moving parts, designed for long-term operation. Air temperature, wind direction, relative humidity, wind speed, precipitation and air radioactivity are measured. The sensors correspond to the Austrian standard OeNORM M9490 (meteorological measurements for air monitoring). The SSM-1 radiation protection survey meter was designed according to the requirements specified by the Austrian postal authorities for stationary radiation warning systems and licensed by the Austrian Federal Office of Weights and Measures (Bundesamt fuer Eich- und Vermessungswesen). The data-logger is based on the HYDRODAT stations installed in Austria, Slovakia and Bulgaria. It performs the following tasks: acquisition and processing of data measured by the sensors and SSM-1; data archiving; data transmission to the host; formation of calculation values; operative functions. Network communication between one or more data-loggers and the host computer is by cable or radio transmission

  11. Coherent radiation from extensive air showers

    International Nuclear Information System (INIS)

    The generic properties of the emission of coherent radiation from a moving charge distribution are discussed. The general structure of the charge and current distributions in an extensive air shower are derived. These are subsequently used to develop a very intuitive picture for the properties of the emitted radio pulse. Using this picture can be seen that the structure of the pulse is a direct reflection of the shower profile. At higher frequencies the emission is suppressed because the wavelength is shorter than the important length scale in the shower. It is shown that radio emission can be used to distinguish proton- and iron-induced air showers.

  12. One-dimensional hydro-kinetic modelling of the decaying arc in air-PA66-copper mixtures: I. Chemical kinetics, thermodynamics, transport and radiative properties

    International Nuclear Information System (INIS)

    A one-dimensional hydro-kinetic model is developed to study arc extinction in a low-voltage breaking device. In part 1 of this double paper, the data necessary for the implementation of the hydro-kinetic model are presented. The equilibrium composition of the plasma is derived from the law of mass action. Mixtures of air and materials ablated from the thermoplastic wall (PA66, monomer C12H22O2N2) and from the contacts (copper) are considered. Thermodynamic properties such as mass density, enthalpy and specific heat at constant pressure are then calculated. Transport coefficients (viscosity, electrical conductivity and thermal conductivity) are determined with the Chapman-Enskog theory. Concerning radiation, the net emission coefficient, corresponding to the power radiated per unit volume and per unit solid angle, is calculated. Finally, for chemical kinetics, a reliable set of reaction rate coefficients linking the chemical species of the plasma is compiled. Particular attention is paid to ionization and recombination of atomic species which are obtained with the 'bottleneck' method.

  13. Thermal computations for electronics conductive, radiative, and convective air cooling

    CERN Document Server

    Ellison, Gordon

    2010-01-01

    IntroductionPrimary mechanisms of heat flowConductionApplication example: Silicon chip resistance calculationConvectionApplication example: Chassis panel cooled by natural convectionRadiationApplication example: Chassis panel cooled only by radiation 7Illustrative example: Simple thermal network model for a heat sinked power transistorIllustrative example: Thermal network circuit for a printed circuit boardCompact component modelsIllustrative example: Pressure and thermal circuits for a forced air cooled enclosureIllustrative example: A single chip package on a printed circuit board-the proble

  14. Mental models of radiation

    International Nuclear Information System (INIS)

    Laymen and experts participated in interviews designed to reveal their 'mental models' of the processes potentially causing the miscommunications between experts and the public. We analyzed their responses in terms of an 'expert model' circumscribing scientifically relevant information. From results, there are gaps even between experts. Experts on internal exposure focused mainly on artificial radiation and high level of radiation. Experts on radiation biology focused on medical radiation, level of risk, environmental radiation, and hot springs. Experts on dosimetric performance focused on atomic power generation and needs of radiological protection. It means that even experts, they have interests only on their own specialized field. (author)

  15. Air-crew radiation dosimetry - last development

    International Nuclear Information System (INIS)

    Exposure to cosmic radiation increases rapidly with the altitude. At the flight levels of commercial aircraft it is of the order of several μSv per hour. The most of air-crew are exposed regularly to the effective dose exceeding 1 mSv per year, the limit of exposure of non-professionals defined in ICRP 60 recommendation. That is why this problem has been intensively studied from many aspects since the beginning of 90's. This contribution summarises new developments in the field during last two years. First, new international activities are presented, further, new achievement obtained mainly in the author's laboratory are presented and discussed. (authors)

  16. Air quality and radiative forcing impacts of anthropogenic volatile organic compound emissions from ten world regions

    OpenAIRE

    M. M. Fry; M. D. Schwarzkopf; Adelman, Z.; West, J. J.

    2013-01-01

    Non-methane volatile organic compounds (NMVOCs) influence air quality and global climate change through their effects on secondary air pollutants and climate forcers. Here we simulate the air quality and radiative forcing (RF) impacts of changes in ozone, methane, and sulfate from halving anthropogenic NMVOC emissions globally and from 10 regions individually, using a global chemical transport model and a standalone radiative transfer model. Halving global NMVOC emissions decreases glo...

  17. Air quality and radiative forcing impacts of anthropogenic volatile organic compound emissions from ten world regions

    OpenAIRE

    M. M. Fry; M. D. Schwarzkopf; Adelman, Z.; West, J. J.

    2014-01-01

    Non-methane volatile organic compounds (NMVOCs) influence air quality and global climate change through their effects on secondary air pollutants and climate forcers. Here we simulate the air quality and radiative forcing (RF) impacts of changes in ozone, methane, and sulfate from halving anthropogenic NMVOC emissions globally and from 10 regions individually, using a global chemical transport model and a standalone radiative transfer model. Halving global NMVOC emissions de...

  18. INEEL AIR MODELING PROTOCOL ext

    Energy Technology Data Exchange (ETDEWEB)

    C. S. Staley; M. L. Abbott; P. D. Ritter

    2004-12-01

    Various laws stemming from the Clean Air Act of 1970 and the Clean Air Act amendments of 1990 require air emissions modeling. Modeling is used to ensure that air emissions from new projects and from modifications to existing facilities do not exceed certain standards. For radionuclides, any new airborne release must be modeled to show that downwind receptors do not receive exposures exceeding the dose limits and to determine the requirements for emissions monitoring. For criteria and toxic pollutants, emissions usually must first exceed threshold values before modeling of downwind concentrations is required. This document was prepared to provide guidance for performing environmental compliance-driven air modeling of emissions from Idaho National Engineering and Environmental Laboratory facilities. This document assumes that the user has experience in air modeling and dose and risk assessment. It is not intended to be a "cookbook," nor should all recommendations herein be construed as requirements. However, there are certain procedures that are required by law, and these are pointed out. It is also important to understand that air emissions modeling is a constantly evolving process. This document should, therefore, be reviewed periodically and revised as needed. The document is divided into two parts. Part A is the protocol for radiological assessments, and Part B is for nonradiological assessments. This document is an update of and supersedes document INEEL/INT-98-00236, Rev. 0, INEEL Air Modeling Protocol. This updated document incorporates changes in some of the rules, procedures, and air modeling codes that have occurred since the protocol was first published in 1998.

  19. Investigation of infra-red and nonequilibrium air radiation

    Science.gov (United States)

    Kruger, Charles H.

    1995-02-01

    This report describes progress on the first year of a research program on the infrared radiation of air plasmas conducted in the High Temperature Gasdynamics Laboratory at Stanford University. This program is intended to investigate the masking of infrared signatures by the air plasma formed behind the bow shock of high velocity missiles. To this date, the radiative emission of air plasmas in the infrared has been the object of few experimental investigations, and although several infrared systems are already modeled in radiation codes such as NEQAIR, measurements are required to validate numerical predictions and indicate whether all transitions of importance are accounted for. The present program is motivated by the fact that 9 excited states (A, B, C, D, B', F, H, and H') of NO radiate in the infrared, especially between 1 and 1.5 microns where at least 9 transitions involving can be observed. Because these IR transitions are relatively well separated from each other, excited NO states concentrations can be easily measured, thus providing essential information on excited-state chemistry for use in optical diagnostics or in electronic excitation model validation. Developing accurate collisional-radiative models for these excited NO states is of importance as the UV-VUV transitions of NO (beta, gamma, epsilon, beta prime, gamma prime) produce a major, if not dominant, fraction of the radiation emitted by air plasmas. During the first year of the program, research has focused on the spectral range 1.0 to 1.5 microns, as detailed in Section 2 of this report. The measurements, conducted in a 50 kW radio-frequency inductively coupled plasma torch operating on air at atmospheric pressure, extend previous shock tube investigations by Wray to a wider spectral range (1.0 to 1.5 microns vs 0.9 to 1.2 microns) and higher temperatures (7600 K in the plasma torch versus 6700 K in the shock-tube). These higher temperatures in the present experiment have made it possible to observe high-lying excited NO states that were previously undetectable. These measurements are currently being extended up to 5 microns, with particular attention paid to the rovibronic bands of ground state NO, molecular continua, CO transitions, and other systems of importance. Publications and presentations resulting from or related to this work are cited in Section 3, and Section 4 lists the personnel who contributed to this report.

  20. Response of air stagnation frequency to anthropogenically enhanced radiative forcing

    International Nuclear Information System (INIS)

    Stagnant atmospheric conditions can lead to hazardous air quality by allowing ozone and particulate matter to accumulate and persist in the near-surface environment. By changing atmospheric circulation and precipitation patterns, global warming could alter the meteorological factors that regulate air stagnation frequency. We analyze the response of the National Climatic Data Center (NCDC) air stagnation index (ASI) to anthropogenically enhanced radiative forcing using global climate model projections of late-21st century climate change (SRESA1B scenario). Our results indicate that the atmospheric conditions over the highly populated, highly industrialized regions of the eastern United States, Mediterranean Europe, and eastern China are particularly sensitive to global warming, with the occurrence of stagnant conditions projected to increase by 12–25% relative to late-20th century stagnation frequencies (3–18 + days yr−1). Changes in the position/strength of the polar jet, in the occurrence of light surface winds, and in the number of precipitation-free days all contribute to more frequent late-21st century air mass stagnation over these high-population regions. In addition, we find substantial inter-model spread in the simulated response of stagnation conditions over some regions using either native or bias corrected global climate model simulations, suggesting that changes in the atmospheric circulation and/or the distribution of precipitation represent important sources of uncertainty in the response of air quality to global warming. (letter)

  1. Response of air stagnation frequency to anthropogenically enhanced radiative forcing

    Science.gov (United States)

    Horton, Daniel E.; Harshvardhan; Diffenbaugh, Noah S.

    2012-12-01

    Stagnant atmospheric conditions can lead to hazardous air quality by allowing ozone and particulate matter to accumulate and persist in the near-surface environment. By changing atmospheric circulation and precipitation patterns, global warming could alter the meteorological factors that regulate air stagnation frequency. We analyze the response of the National Climatic Data Center (NCDC) air stagnation index (ASI) to anthropogenically enhanced radiative forcing using global climate model projections of late-21st century climate change (SRESA1B scenario). Our results indicate that the atmospheric conditions over the highly populated, highly industrialized regions of the eastern United States, Mediterranean Europe, and eastern China are particularly sensitive to global warming, with the occurrence of stagnant conditions projected to increase by 12-25% relative to late-20th century stagnation frequencies (3-18 + days yr-1). Changes in the position/strength of the polar jet, in the occurrence of light surface winds, and in the number of precipitation-free days all contribute to more frequent late-21st century air mass stagnation over these high-population regions. In addition, we find substantial inter-model spread in the simulated response of stagnation conditions over some regions using either native or bias corrected global climate model simulations, suggesting that changes in the atmospheric circulation and/or the distribution of precipitation represent important sources of uncertainty in the response of air quality to global warming.

  2. Solar radiation models - review

    Directory of Open Access Journals (Sweden)

    M. Jamil Ahmad, G.N. Tiwari

    2010-05-01

    Full Text Available In the design and study of solar energy, information on solar radiation and its components at a given location is very essential. Solar radiation data are required by solar engineers, architects, agriculturists and hydrologists for many applications such as solar heating, cooking, drying and interior illumination of buildings. For this purpose, in the past, several empirical correlations have been developed in order to estimate the solar radiation around the world. The main objective of this study is to review the global solar radiation models available in the literature. There are several formulae which relate global radiation to other climatic parameters such as sunshine hours, relative humidity and maximum temperature. The most commonly used parameter for estimating global solar radiation is sunshine duration. Sunshine duration can be easily and reliably measured and data are widely available.

  3. AirPEx: Air Pollution Exposure Model

    OpenAIRE

    Freijer JI; Bloemen HJTh; Loos S de; Marra M; Rombout PJA; Steentjes GM; Veen MP van

    1997-01-01

    Analysis of inhalatory exposure to air pollution is an important area of investigation when assessing the risks of air pollution for human health. Inhalatory exposure research focuses on the exposure of humans to air pollutants and the entry of these pollutants into the human respiratory tract. The principal grounds for studying the inhalatory exposure of humans to air pollutants are formed by the need for realistic exposure/dose estimates to evaluate the health effects of these pollutants....

  4. AirPEx: Air Pollution Exposure Model

    OpenAIRE

    Freijer JI; Bloemen HJTh; Loos S de; Marra M; Rombout PJA; Steentjes GM; van Veen MP; LBO

    1997-01-01

    Analysis of inhalatory exposure to air pollution is an important area of investigation when assessing the risks of air pollution for human health. Inhalatory exposure research focuses on the exposure of humans to air pollutants and the entry of these pollutants into the human respiratory tract. The principal grounds for studying the inhalatory exposure of humans to air pollutants are formed by the need for realistic exposure/dose estimates to evaluate the health effects of these pollutants. T...

  5. Models for radiation carcinogenesis

    International Nuclear Information System (INIS)

    Epidemiological studies and animal experiments for statistical reasons will not be able to answer the questions of the effects on human health of a radiation exposure in the important range below 10 mSv - at least not without significant progress in 'molecular epidemiology'. Mechanistic models for radiation carcinogenesis may be able to seriously test the working hypothesis presently often used of a linear (or linear-quadratic) dose effect relationship without dose threshold for stochastic radiation effects and to provide additional information on its time, age and dose rate dependencies. Some approaches using such models are oulined and problems encountered are discussed. (orig.)

  6. Assessing the accuracy of mathematical models used in thermoelectric simulation: Thermal influence of insulated air zone and radiation heat

    International Nuclear Information System (INIS)

    An accurate mathematical model of thermoelectric modules (TEMs) provides the basis for the analysis and design of thermoelectric conversion system. TEM models from the literature are only valid for the heat transfer of N-type and P-type thermoelectric couples without considering air around the actual thermoelectric couples of TEMs. In fact, air space imposes significant influence on the model computational accuracy, especially for a TEM with large air space inside. In this study, heat transfer analyses of air between the TEM cold and hot plates were carried out in order to propose a new mathematical model that minimises simulation errors. This model was applied to analyse characteristic parameters of two typical TEMs, and the ratio of cross-sectional area of air space to thermocouples were 48.2% and 80.0%, respectively. The average relative errors in simulation decreased from 5.2% to 2.8% and from 12.8% to 3.7%, respectively. It is noted that our new model gives result more accurate than models from the literature provided that higher temperature difference occurs between hot side and cold side of TEM. Thus, the proposed model is of theoretical significance in guiding future design of TEMs for high-power or large-temperature-difference thermoelectric conversion systems. - Highlights: • Built a new accurate model for thermoelectric modules with inner air heat transfer. • Analysed the influence on heat transfer of the air within the TEM∗. • Reduced simulation errors for high-power thermoelectric conversion systems. • Two typical TEMs were measured with a good agreement with theoretical results. • ∗TEM is the abbreviation of thermoelectric module

  7. Determination of the potential radiation exposure of the population close to the Asse II mine caused by deduction of radioactive substances with the discharge air in the normal operation using the ''Atmospheric Radionuclide-Transport-Model'' (ARTM)

    International Nuclear Information System (INIS)

    Between 1967 and 1978 125.787 packages filled with low-level and intermediate-level radioactive waste were emplaced in the mining plant Asse II. Volatile radioactive substances like H-3, C-14 and Rn-222 are released from the emplaced waste. These substances reach the ventilated parts of the mine and are released with the discharge air. The potential radiation exposure of the population caused by deduction of radioactive substances with the discharge air in the normal operation is determined by the ''Atmospheric Radionuclide-Transport-Model'' (ARTM). As result the maximal deductions of volatile radioactive substances with the discharge air in the normal operation of the Asse II mine lead to radiation exposure of the population, which is considerably lower than the permissible values of application rate.

  8. ATHENA radiation model

    International Nuclear Information System (INIS)

    The ATHENA computer program has many features that make it desirable to use as a space reactor evaluation tool. One of the missing features was a surface-to-surface thermal radiation model. A model was developed that allows any of the regular ATHENA heat slabs to radiate to any other heat slab. The view factors and surface emissivities must be specified by the user. To verify that the model was properly accounting for radiant energy transfer, two different types of test calculations were performed. Both calculations have excellent results. The updates have been used on both the INEL CDC-176 and the Livermore Cray. 7 refs., 2 figs., 6 tabs

  9. Radiation risk estimation models

    International Nuclear Information System (INIS)

    Cancer risk models and their relationship to ionizing radiation are discussed. There are many model assumptions and risk factors that have a large quantitative impact on the cancer risk estimates. Other health end points such as mental retardation may be an even more serious risk than cancer for those with in utero exposures. 8 references

  10. Ambient radiation level and air borne activity at RRCAT, Indore

    International Nuclear Information System (INIS)

    In order to assess the impact on ambient radiation level and airborne activity after the nuclear accident at Fukushima, radioactivity levels were measured at RRCAT Indore premises by Emergency Response Centre (ERC), RRCAT. The report presents the monitoring data obtained from IERMON (Indian Environmental Radiation Monitoring Network) and from air sampling carried out at RRCAT premises. The monitoring was performed over a period of around one and half months from 15th March 2011 to 5th May 2011. The IERMON data indicated no increase in radiation level at RRCAT premises. Air borne activity data obtained from air sampler also indicated no increase in air borne activity above background level

  11. Solar radiation modelling

    Energy Technology Data Exchange (ETDEWEB)

    Zaksek, Klemen; Podobnikar, Tomaz; Ostir, Kristof [ZRC SAZU, Inst. of Anthropological and Spatial Studies, Ljubljana (Slovenia)

    2005-03-15

    The Sun is the main energy source of the life on the Earth. Thus, solar radiation energy data and models are important for many areas of research and applications. Many parameters influence the amount of solar energy at a particular standing point of the Earth's surface; therefore, many solar radiation models were produced in the last few years. Solar radiation energy depends mostly on incidence angle, which is defined by astronomical and surface parameters. Our solar radiation model is based on defining incidence angle by computing normal-to-the-surface tangent plane and direction of the Sun. If a part of the surface is in the shadow, it receives lesser energy than sunny areas. That is why shadow determination is an important part of the model. The sky is usually not completely clear, so meteorological parameters had to be integrated into the model. Meteorological model distinguishes among direct and diffuse Sun radiation. The model was tested and implemented for the whole of Slovenia and it was also compared with previous studies. Case study surface data were calculated from the DEM with a 25 m resolution. The astronomical data, which were required for virtual Sun motion simulation around the Earth, were derived from the astronomical almanac. Meteorological data were acquired from observed mean values on 24 meteorological stations between 1961 and 1990. All calculations were made for hours and decades and finally, the annual quasiglobal radiation energy, which is the energy received by inclined plane from the Sun in one year, was calculated from the sum of all the energies of all the decades. (Author)

  12. Geostatistical models for air pollution

    International Nuclear Information System (INIS)

    The objective of this paper is to present geostatistical models applied to the spatial characterisation of air pollution phenomena. A concise presentation of the geostatistical methodologies is illustrated with practical examples. The case study was conducted in an underground copper-mine located on the southern of Portugal, where a biomonitoring program using lichens has been implemented. Given the characteristics of lichens as indicators of air pollution it was possible to gather a great amount of data in space, which enabled the development and application of geostatistical methodologies. The advantages of using geostatistical models compared with deterministic models, as environmental control tools, are highlighted. (author)

  13. Backward air mass trajectory analysis for the first cloud and radiation testbed site at Lamont, Oklahoma

    International Nuclear Information System (INIS)

    The size distribution and composition of aerosols measured at a specific location depend on the origin and the trajectory of the air mass passing over it. Backward air mass trajectory analysis can be used to (1) identify the characteristics of an air mass and (2) help to determine which aerosol model should be used in LOWTRAN 7 for radiation calculations. Examining the trajectory is not sufficient to characterize the aerosol composition of the air mass at the site. Additional analyses must be performed along the trajectory to understand how the original air mass has or has not been modified. Height analyses, precipitation events, the vertical temperature structure of the atmosphere, and the relative humidity field, as well as other physical parameters, are important for classifying an air mass after it has traveled for a few days. The primary objective of this research is to characterize a climatology of air masses that pass over the Atmospheric Radiation Measurement (ARM) Program's Cloud and Radiation Testbed (CART) site at Lamont, Oklahoma. A three-dimensional air mass trajectory model and a method of analysis were developed at the Environmental Measurements Laboratory (EML). The classification of the air mass types (rural, marine, urban or desert) is used to decide which aerosol model is appropriate for calculations in a radiation model, such as LOWTRAN 7

  14. Office of radiation and indoor air: Program description

    International Nuclear Information System (INIS)

    The goal of the Environmental Protection Agency's (EPA) Office of Radiation and Indoor Air is to protect the public and the environment from exposures to radiation and indoor air pollutants. The Office develops protection criteria, standards, and policies and works with other programs within EPA and other agencies to control radiation and indoor air pollution exposures; provides technical assistance to states through EPA's regional offices and other agencies having radiation and indoor air protection programs; directs an environmental radiation monitoring program; responds to radiological emergencies; and evaluates and assesses the overall risk and impact of radiation and indoor air pollution. The Office is EPA's lead office for intra- and interagency activities coordinated through the Committee for Indoor Air Quality. It coordinates with and assists the Office of Enforcement in enforcement activities where EPA has jurisdiction. The Office disseminates information and works with state and local governments, industry and professional groups, and citizens to promote actions to reduce exposures to harmful levels of radiation and indoor air pollutants

  15. Air Conditioner Compressor Performance Model

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Ning; Xie, YuLong; Huang, Zhenyu

    2008-09-05

    During the past three years, the Western Electricity Coordinating Council (WECC) Load Modeling Task Force (LMTF) has led the effort to develop the new modeling approach. As part of this effort, the Bonneville Power Administration (BPA), Southern California Edison (SCE), and Electric Power Research Institute (EPRI) Solutions tested 27 residential air-conditioning units to assess their response to delayed voltage recovery transients. After completing these tests, different modeling approaches were proposed, among them a performance modeling approach that proved to be one of the three favored for its simplicity and ability to recreate different SVR events satisfactorily. Funded by the California Energy Commission (CEC) under its load modeling project, researchers at Pacific Northwest National Laboratory (PNNL) led the follow-on task to analyze the motor testing data to derive the parameters needed to develop a performance models for the single-phase air-conditioning (SPAC) unit. To derive the performance model, PNNL researchers first used the motor voltage and frequency ramping test data to obtain the real (P) and reactive (Q) power versus voltage (V) and frequency (f) curves. Then, curve fitting was used to develop the P-V, Q-V, P-f, and Q-f relationships for motor running and stalling states. The resulting performance model ignores the dynamic response of the air-conditioning motor. Because the inertia of the air-conditioning motor is very small (H<0.05), the motor reaches from one steady state to another in a few cycles. So, the performance model is a fair representation of the motor behaviors in both running and stalling states.

  16. Radiation Physics for Space and High Altitude Air Travel

    Science.gov (United States)

    Cucinotta, F. A.; Wilson, J. W.; Goldhagen, P.; Saganti, P.; Shavers, M. R.; McKay, Gordon A. (Technical Monitor)

    2000-01-01

    Galactic cosmic rays (GCR) are of extra-solar origin consisting of high-energy hydrogen, helium, and heavy ions. The GCR are modified by physical processes as they traverse through the solar system, spacecraft shielding, atmospheres, and tissues producing copious amounts of secondary radiation including fragmentation products, neutrons, mesons, and muons. We discuss physical models and measurements relevant for estimating biological risks in space and high-altitude air travel. Ambient and internal spacecraft computational models for the International Space Station and a Mars mission are discussed. Risk assessment is traditionally based on linear addition of components. We discuss alternative models that include stochastic treatments of columnar damage by heavy ion tracks and multi-cellular damage following nuclear fragmentation in tissue.

  17. Frontiers in air quality modelling

    Directory of Open Access Journals (Sweden)

    A. Colette

    2013-08-01

    Full Text Available The first pan-European kilometre-scale atmospheric chemistry simulation is introduced. The continental-scale air pollution episode of January 2009 is modelled with the CHIMERE offline chemistry-transport model with a massive grid of 2 million horizontal points, performed on 2000 CPU of a high performance computing system hosted by the Research and Technology Computing Center at the French Alternative Energies and Atomic Energy Commission (CCRT/CEA. Besides the technical challenge, we find that model biases are significantly reduced, especially over urban areas. The high resolution grid also allows revisiting the contribution of individual city plumes to the European burden of pollution, providing new insights for designing air pollution control strategies.

  18. Macroscopic model of radio emission from extensive air showers

    International Nuclear Information System (INIS)

    A macroscopic model of radio emission from extensive air showers is developed. This model is appropriate for calculating this radio emission at frequencies below 100 MHz. It is constructed on the basis of an analysis of the radiation integral and is verified by comparing field observables predicted by the model with the respective results obtained within the microscopic approach to calculating radio emission from extensive air showers.

  19. Albedo effect on radiative errors in air temperature measurements

    OpenAIRE

    Huwald, H.; C. W. Higgins; Boldi, M.-O.; Bou-Zeid, E.; Lehning, Michael; Parlange, M.B.

    2009-01-01

    Most standard air temperature measurements are subject to significant errors mainly due to sensor heating by solar radiation, even when the measurement principle is accurate and precise. We present various air temperature measurements together with other measurements of meteorological parameters using different sensor systems at a snow-covered and a vegetated site. Measurements from naturally ventilated air temperature sensors in multiplate shields are compared to temperatures measured using ...

  20. Air quality dispersion models from energy sources

    International Nuclear Information System (INIS)

    Along with the continuing development of new air quality models that cover more complex problems, in the Clean Air Act, legislated by the US Congress, a consistency and standardization of air quality model applications were encouraged. As a result, the Guidelines on Air Quality Models were published, which are regularly reviewed by the Office of Air Quality Planning and Standards, EPA. These guidelines provide a basis for estimating the air quality concentrations used in accessing control strategies as well as defining emission limits. This paper presents a review and analysis of the recent versions of the models: Simple Terrain Stationary Source Model; Complex Terrain Dispersion Model; Ozone,Carbon Monoxide and Nitrogen Dioxide Models; Long Range Transport Model; Other phenomenon Models:Fugitive Dust/Fugitive Emissions, Particulate Matter, Lead, Air Pathway Analyses - Air Toxic as well as Hazardous Waste. 8 refs., 4 tabs., 2 ills

  1. Air pollution radiative forcing from specific emissions sectors at 2030

    Science.gov (United States)

    Unger, Nadine; Shindell, Drew T.; Koch, Dorothy M.; Streets, David G.

    2008-01-01

    Reduction of short-lived air pollutants can contribute to mitigate global warming in the near-term with ancillary benefits to human health. However, the radiative forcings of short-lived air pollutants depend on the location and source type of the precursor emissions. We apply the Goddard Institute for Space Studies atmospheric composition-climate model to quantify near-future (2030 A1B) global annual mean radiative forcing by ozone (O3) and sulfate from six emissions sectors in seven geographic regions. At 2030 the net forcings from O3, sulfate, black and organic carbon, and indirect CH4 effects for each emission sector are (in mWm-2) biomass burning, +95; domestic, +68; transportation, +67; industry, -131; and power, -224. Biomass burning emissions in East Asia and central and southern Africa, domestic biofuel emissions in East Asia, south Asia, and central and southern Africa, and transportation emissions in Europe and North America have large net positive forcings and are therefore attractive targets to counter global warming. Power and industry emissions from East Asia, south Asia, and north Africa and the Middle East have large net negative forcings. Therefore air quality control measures that affect these regional sectors require offsetting climate measures to avoid a warming impact. Linear relationships exist between O3 forcing and biomass burning and domestic biofuel CO precursor emissions independent of region with sensitivity of +0.2 mWm-2/TgCO. Similarly, linear relationships exist between sulfate forcing and SO2 precursor emissions that depend upon region but are independent of sector with sensitivities ranging from -3 to -12 mWm-2/TgS.

  2. Molecular Bremsstrahlung Radiation at GHz Frequencies in Air

    CERN Document Server

    Samarai, I Al; Deligny, O; Letessier-Selvon, A; Montanet, F; Settimo, M; Stassi, P

    2016-01-01

    A detection technique for ultra-high energy cosmic rays, complementary to the fluorescence technique, would be the use of the molecular Bremsstrahlung radiation emitted by low-energy ionization electrons left after the passage of the showers in the atmosphere. In this article, a detailed estimate of the spectral intensity of photons at ground level originating from this radiation is presented. The spectral intensity expected from the passage of the high-energy electrons of the cascade is also estimated. The absorption of the photons in the plasma of electrons/neutral molecules is shown to be negligible. The obtained spectral intensity is shown to be $2\\times10^{-21} $W cm$^{-2}$ GHz$^{-1}$ at 10 km from the shower core for a vertical shower induced by a proton of $10^{17.5}$ eV. In addition, a recent measurement of Bremsstrahlung radiation in air at gigahertz frequencies from a beam of electrons produced at 95 keV by an electron gun is also discussed and reasonably reproduced by the model.

  3. Molecular bremsstrahlung radiation at GHz frequencies in air

    Science.gov (United States)

    Al Samarai, Imen; Bérat, Corinne; Deligny, Olivier; Letessier-Selvon, Antoine; Montanet, François; Settimo, Mariangela; Stassi, Patrick

    2016-03-01

    A detection technique for ultra-high-energy cosmic rays, complementary to the fluorescence technique, would be the use of the molecular bremsstrahlung radiation emitted by low-energy ionization electrons left after the passage of the showers in the atmosphere. In this article, a detailed estimate of the spectral intensity of photons at ground level originating from this radiation is presented. The spectral intensity expected from the passage of the high-energy electrons of the cascade is also estimated. The absorption of the photons in the plasma of electrons and neutral molecules is shown to be negligible. The obtained spectral intensity is shown to be 2 ×1 0-21 W cm-2 GHz-1 at 10 km from the shower core for a vertical shower induced by a proton of 1 017.5 eV . In addition, a recent measurement of bremsstrahlung radiation in air at gigahertz frequencies from a beam of electrons produced at 95 keV by an electron gun is also discussed and reasonably reproduced by the model.

  4. Radiative divertor modeling studies

    International Nuclear Information System (INIS)

    A two-dimensional fluid code called UEDGE is used to simulate the edge plasma in tokamak divertors and to evaluate methods for reducing the heat load on divertor plates by radiating some of the power before it reaches the plates. UEDGE is a fully-implicit code being developed jointly by us, R.B. Campbell and D.A. Knoll. For these studies, UEDGE uses a banded matrix solver and a fixed-fraction impurity model. Work is presently underway with Campbell and Knoll to include a memory-efficient iterative solver and a model of impurity transport. Simulations of the proposed TPX device show that a few percent nitrogen concentration in the scrape-off layer can radiate up to 80% of the divertor power, thus reducing the peak heat flux and electron temperature at the divertor plate to acceptable values. A comparison of the neutral gas distribution from the DEGAS Monte Carlo neutrals code confirms the validity of our fluid neutrals model. (author) 12 refs., 8 figs

  5. Radiative divertor modeling studies

    International Nuclear Information System (INIS)

    A two-dimensional fluid code called UEDGE is used to simulate the edge plasma in tokamak divertors and to evaluate methods for reducing the heat load on divertor plates by radiating some of the power before it reaches the plates. UEDGE is a fully-implicit code being developed jointly by us, D. A. Knoll and R. B. Campbell. For these studies, UEDGE uses a banded matrix solver and a fixed-fraction impurity model. Work is presently underway with Knoll and Campbell to include a memory-efficient iterative solver and a model of impurity transport. Simulations of the proposed TPX device show that a few percent nitrogen concentration in the scrape-off layer can radiate up to 80% of the divertor power, thus reducing the peak heat flux and electron temperature at the divertor plate to acceptable values. A comparison of the neutral gas distribution from UEDGE with results from the DEGAS Monte Carlo neutrals code confirms the validity of our fluid neutrals model

  6. Biophysical modelling in radiation protection

    International Nuclear Information System (INIS)

    Biophysical models have historically provided essential concepts by which risk estimates have been extrapolated from observations in humans and animals to the low radiation levels of prime relevance in radiation protection. But there remain major uncertainties, and modelling has an essential continuing role to reduce these and seek alternative approaches in the light of advancing knowledge. Particularly important are the capabilities of single radiation tracks in cells, and the great differences between radiations, in perturbing biological processes. (author)

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

    Science.gov (United States)

    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. Characterization of 3D Cirrus Cloud and Radiation Fields Using ARS/AIRS/MODIS data and its Application to Climate Model

    Energy Technology Data Exchange (ETDEWEB)

    Liou, Kuo-Nan [Univ. of California, Los Angeles, CA (United States); Ou, S. C. [Univ. of California, Los Angeles, CA (United States); Gu, Y. [Univ. of California, Los Angeles, CA (United States); Takano, Y. [Univ. of California, Los Angeles, CA (United States)

    2016-02-22

    During the report period, we have made the following research accomplishments. First, we performed analysis for a number of MODIS scenes comprising of heavy dust events and ice clouds, covering regions of frequent dust outbreaks in East Asia, Middle East, and West Africa, as well as areas associated with long-range dust transports over the Equatorial Tropical Atlantic Ocean. These scenes contain both dust/aerosols and clouds. We collected suitable aerosol/ice-cloud data, correlated ice cloud and aerosol parameters by means of statistical analysis, and interpreted resulting correlation trends based on the physical principles governing cloud microphysics. Aerosol and cloud optical depths and cloud effective particle size inferred from MODIS for selected domains were analyzed from which the parameters including dust aerosol number concentration, ice cloud water path, and ice particle number concentration were subsequently derived. We illustrated that the Twomey (solar albedo) effect can be statistically quantified based on the slope of best-fit straight lines in the correlation study. Analysis of aerosol and cloud retrieval products revealed that for all cases, the region with a larger dust aerosol optical depth is always characterized by a smaller cloud particle size, consistent with the Twomey hypothesis for aerosol-cloud interactions. Second, we developed mean correlation curves with uncertainties associated with small ice-crystal concentration observations for the mean effective ice crystal size (De) and ice water content (IWC) by dividing the atmosphere into three characteristic regions: Tropics cirrus, Midlatitude cirrus, including a temperature classification to improve correlation, and Arctic ice clouds. We illustrated that De has a high correlation with IWC based on theoretical consideration and analysis of thousands of observed ice crystal data obtained from a number of ARM-DOE field campaigns and other experiments. The correlation has the form: ln(De) = a + b ln(IWC) + c ((ln(IWC))2, where a, b, and c are fitting coefficients and are functions of three regions. We demonstrated that this correlation can be effectively incorporated in GCMs and climate models that predict IWC - a significant advance in ice microphysics parameterization for interactive cloud-radiation analysis and feedback. Substantial July mean differences are shown in the OLR (W/m2) and precipitation (mm/day) patterns between UCLA GCM simulations based on Des determined from the De-IWC correlations and the control run using a fixed ice crystal size. Third, in order to improve the computation of spectral radiative transfer processes in the WRF model, we developed a consistent and efficient radiation scheme that can better resolve the spectral bands, determine the cloud optical properties, and provide more reliable and accurate radiative heating fields. In the newly developed radiation module, we have implemented in WRF a modified and improved version referred to as the Fu-Liou-Gu scheme, which includes a combination of delta-four-stream and delta-two-stream approximations for solar and IR flux calculations, respectively. This combination has been proven to be computationally efficient and at the same time to produce a high degree of accuracy. The incorporation of nongray gaseous absorption in multiple scattering atmospheres was based on the correlated k-distribution method. The solar and IR spectra are divided into 6 and 12 bands, respectively, according to the location of absorption bands of H2O, CO2, O3, CH4, N2O, and CFCs. We further included absorption by the water vapor continuum and a number of minor absorbers in the solar spectrum leading to an additional absorption of solar flux in a clear atmosphere on the order of 1-3 W/m2. Additionally, we incorporated the ice microphysics parameterization that includes an interactive mean effective ice crystal size in association with radiation parameterizations. The Fu-Liou-Gu scheme is an ideal tool for the simulation of radiative transfer and ice microphysics within the domain of WRF. It is particularly useful for studying direct and indirect aerosol radiative effects associated with ice cloud formation. The newly implemented radiation module has been demonstrated to work well in WRF and can be effectively used for studies related to cirrus cloud formation and evolution as well as aerosol-cloud-radiation interactions. With the newly implemented radiation scheme, the simulations of cloud cover and ice water path have been improved for cirrus clouds, with a more consistent comparison with the corresponding MODIS observations, especially for optically thin cirrus with an improvement of about 20% in the simulated mean ice water path.

  9. Plasma Properties Induced in Air by Alpha Radiation

    International Nuclear Information System (INIS)

    The plasma characteristics of partially dissociated and ionized air due to alpha emissions from a radioisotope surface material have been investigated. Preliminary estimates of average electron energy, electron attachment coefficient, electron- ion recombination coefficient, distribution of equilibrium electron density, plasma frequency, electrical conductivity, and dielectric properties normal to a radioactive surface have been made for alpha-radiated air. The analytical procedure is based on Rutherford scattering theory from which it was found that the average kinetic energy of secondary electrons is 113.5 eV, that of tertiary electrons is 8.2 eV, and that of the total number of free electrons is 43.2 eV. The temporal average electron energy in room temperature air is estimated to be approximately 20 eV, and the dependence of electron attachment coefficient and electron-ion recombination coefficient on average electron energy is recognized. Based on this electron energy dependence, the attachment coefficient was found to be negligible and the recombination coefficient (dissociative) was determined from the thermal plasma experiments of Biondi and Brown as a function of air density. Estimates of average electron density through the ionized air layer adjacent to a polonium-210 surface coating of 2 mCi/in2 were computed to be 109 to 1010 cm3 and its graded distribution normal to the surface was estimated from which its plasma frequency distribution was found. The electron collisional cross-section was determined to be a weak function of electron kinetic energy and the distribution of electrical conductivity and permittivity through the plasma could then be computed, from which it was predicted that a measurable interaction with an electromagnetic wave propagating through an alpha-generated air plasma may occur. An experimental programme was undertaken. The test results show: (1) the average electron density of alpha-bombarded air is 109-1010 cm-3 ; (2) electron attachment in alpha-radiated air is, as assumed, apparently negligible, and (3) dissociative recombination coefficient estimated for an alpha-radiation air plasma is apparently of the correct order of magnitude. The conclusions of this study are that air at normal temperature may be induced by alpha radiation to attain electrical conductivity equivalent to a thermal air plasma at a temperature of approximately 2500°K and that the electrical conductivity of many thermal plasmas (depending upon their composition, ionization potential, basic electron density level, etc.) may be increased by exposure to large quantities of alpha radiation. (author)

  10. Radiation exposure during air and ground transportation

    International Nuclear Information System (INIS)

    The results of a one year study program of radiation exposure experienced on both domestic and international flights of the China Airline and the Far East Airline in the Pacific, Southeast Asia and Taiwan areas and on trains and buses on Taiwan island are reported. CaSO4:Dy thermoluminescent dosimeters were used. It has been shown that transit exposures may amount to 10 times that on the ground with an altitude varying from 3,050 to 12,200 m. (U.K.)

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

    Science.gov (United States)

    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 long-wave radiation remains almost constant during the testing period. To conclude, the final AirT maps have been used to calculate continuous maps of Net Radiation, showing an important application of the output of this work for surface energy balance retrieval.

  12. Lowland rice yield estimates based on air temperature and solar radiation

    International Nuclear Information System (INIS)

    Two regression equations were developed to estimate lowland rice yield as a function of air temperature and incoming solar radiation, during the crop yield production period in Pindamonhangaba, SP, Brazil. The following rice cultivars were used: IAC-242, IAC-100, IAC-101 and IAC-102. The value of optimum air temperature obtained was 25.0°C and of optimum global solar radiation was 475 cal.cm-2, day-1. The best agrometeorological model was the one that related least deviation of air temperature and solar radiation in relation to the optimum value obtained through a multiple linear regression. The yield values estimated by the model showed good fit to actual yields of lowland rice (less than 10%). (author)

  13. Cosmic radiation exposure in subsonic air transport

    Science.gov (United States)

    Wallace, R. W.; Sondhaus, C. A.

    1978-01-01

    Data derived from 1973 statistics on 2.99 million intercity flights carrying 468 million seats were included in the calculations, yielding a total of 581 billion seat-kilometer. The average flight was 1,084 km in length, was flown at an altitude of 9.47 km, and lasted 1.41 h. The average dose rate was 0.20 mrem/h, resulting in an average passenger dose of 2.82 mrem/year and an average crewmember dose of 160 mrem/year. The average radiation dose to the total U.S. population was 0.47 mrem/person/year. These results are in good agreement with data from several experiments performed by us and others in aircraft at various altitudes and latitudes. The significance of these doses to the population is discussed.

  14. Air travel and radiation risks - review of current knowledge

    International Nuclear Information System (INIS)

    Aircrew and passengers are exposed to cosmic radiation, in particular when travelling routes close to the poles and in high altitudes. The paper reviews current radiation measurement and estimation approaches as well as the actual level of cosmic radiation that personnel and travellers receive and summarizes the available epidemiological evidence on health effects of cosmic radiation. On average, German aircrew is exposed to les than 5 mSv per annum, and even frequent travellers only rarely reach values above 1 mSv/year. Cohort studies among aircrew have found very little evidence for an increased incidence or mortality of radiation-associated cancers. Only malignant melanoma rates have consistently found to be increased among male aircrew. Socioeconomic and reproductive aspects are likely to contribute to the slightly elevated breast cancer risk of female aircrew. Cytogenetic studies have not yielded consistent results. Based on these data overall risk increases for cancer among occupationally exposed aircrew appear unlikely. This also applies to air travellers who are usually exposed to much lower radiation levels. Occasional air travel during pregnancy does not pose a significant radiation risk, but further considerations apply in this situation. The currently available studies are limited with regard to methodological issues and case numbers so that a continuation of cohort studies in several European countries is being planned. (orig.)

  15. Stochastic Modeling of Traffic Air Pollution

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    2014-01-01

    In this paper, modeling of traffic air pollution is discussed with special reference to infrastructures. A number of subjects related to health effects of air pollution and the different types of pollutants are briefly presented. A simple model for estimating the social cost of traffic related air...... and using simple Monte Carlo techniques to obtain a stochastic estimate of the costs of traffic air pollution for infrastructures....... pollution is derived. Several authors have published papers on this very complicated subject, but no stochastic modelling procedure have obtained general acceptance. The subject is discussed basis of a deterministic model. However, it is straightforward to modify this model to include uncertain parameters...

  16. Cosmic radiation doses in commercial air travel

    International Nuclear Information System (INIS)

    Sensitivity of both detectors are 0.01 μSv/h for gamma rays and 3 bubbles /μSv for neutrons, satisfactory for the in-flight measurements. Calibration of both detectors are conducted on ground using reference sources of high-energy gamma and neutrons. The measurements are carried out in all commercial flights served by the Eva Air and China Airline; the flight pattern of initial and final ascending/descending, cruising, and landing approach are logged on-line, while the in-flight doses are recorded in cumulative modes Typical result is 42 ± 3 μSv for Taipei-NYC flight route, to which the neutrons contribute more than 50% of the total cosmic doses. Annual dose for crew members can be assessed by the measured data and the information of their flight-hours, aircraft types, flight routes, and flight pattern. The annual doses for crew-members are 108 μSv for domestic service and up to 7200 μSv for international service. (author)

  17. Long and short-term atmospheric radiation analyses based on coupled measurements at high altitude remote stations and extensive air shower modeling

    Science.gov (United States)

    Hubert, G.; Federico, C. A.; Pazianotto, M. T.; Gonzales, O. L.

    2016-02-01

    In this paper are described the ACROPOL and OPD high-altitude stations devoted to characterize the atmospheric radiation fields. The ACROPOL platform, located at the summit of the Pic du Midi in the French Pyrenees at 2885 m above sea level, exploits since May 2011 some scientific equipment, including a BSS neutron spectrometer, detectors based on semiconductor and scintillators. In the framework of a IEAv and ONERA collaboration, a second neutron spectrometer was simultaneously exploited since February 2015 at the summit of the Pico dos Dias in Brazil at 1864 m above the sea level. The both high station platforms allow for investigating the long period dynamics to analyze the spectral variation of cosmic-ray- induced neutron and effects of local and seasonal changes, but also the short term dynamics during solar flare events. This paper presents long and short-term analyses, including measurement and modeling investigations considering the both high altitude stations data. The modeling approach, based on ATMORAD computational platform, was used to link the both station measurements.

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

    Science.gov (United States)

    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.

  19. Water, Air, Earth and Cosmic Radiation

    Science.gov (United States)

    Bassez, Marie-Paule

    2015-06-01

    In the context of the origin of life, rocks are considered mainly for catalysis and adsorption-desorption processes. Here it is shown how some rocks evolve in energy and might induce synthesis of molecules of biological interest. Radioactive rocks are a source of thermal energy and water radiolysis producing molecular hydrogen, H2. Mafic and ultramafic rocks evolve in water and dissolved carbon dioxide releasing thermal energy and H2. Peridotites and basalts contain ferromagnesian minerals which transform through exothermic reactions with the generation of heat. These reactions might be triggered by any heating process such as radioactive decay, hydrothermal and subduction zones or post-shock of meteorite impacts. H2 might then be generated from endothermic hydrolyses of the ferromagnesian minerals olivine and pyroxene. In both cases of mafic and radioactive rocks, production of CO might occur through high temperature hydrogenation of CO2. CO, instead of CO2, was proven to be necessary in experiments synthesizing biological-type macromolecules with a gaseous mixture of CO, N2 and H2O. In the geological context, N2 is present in the environment, and the activation source might arise from cosmic radiation and/or radionuclides. Ferromagnesian and radioactive rocks might consequently be a starting point of an hydrothermal chemical evolution towards the abiotic formation of biological molecules. The two usually separate worlds of rocks and life are shown to be connected through molecular and thermodynamic chemical evolution. This concept has been proposed earlier by the author (Bassez J Phys: Condens Matter 15:L353-L361, 2003, 2008a, 2008b; Bassez Orig Life Evol Biosph 39(3-4):223-225, 2009; Bassez et al. 2011; Bassez et al. Orig Life Evol Biosph 42(4):307-316, 2012, Bassez 2013) without thermodynamic details. This concept leads to signatures of prebiotic chemistry such as radionuclides and also iron and magnesium carbonates associated with serpentine and/or talc, which were discussed at the 2014 European Astrobiology Network Association conference on Signatures of Life.

  20. Water, air, Earth and cosmic radiation.

    Science.gov (United States)

    Bassez, Marie-Paule

    2015-06-01

    In the context of the origin of life, rocks are considered mainly for catalysis and adsorption-desorption processes. Here it is shown how some rocks evolve in energy and might induce synthesis of molecules of biological interest. Radioactive rocks are a source of thermal energy and water radiolysis producing molecular hydrogen, H2. Mafic and ultramafic rocks evolve in water and dissolved carbon dioxide releasing thermal energy and H2. Peridotites and basalts contain ferromagnesian minerals which transform through exothermic reactions with the generation of heat. These reactions might be triggered by any heating process such as radioactive decay, hydrothermal and subduction zones or post-shock of meteorite impacts. H2 might then be generated from endothermic hydrolyses of the ferromagnesian minerals olivine and pyroxene. In both cases of mafic and radioactive rocks, production of CO might occur through high temperature hydrogenation of CO2. CO, instead of CO2, was proven to be necessary in experiments synthesizing biological-type macromolecules with a gaseous mixture of CO, N2 and H2O. In the geological context, N2 is present in the environment, and the activation source might arise from cosmic radiation and/or radionuclides. Ferromagnesian and radioactive rocks might consequently be a starting point of an hydrothermal chemical evolution towards the abiotic formation of biological molecules. The two usually separate worlds of rocks and life are shown to be connected through molecular and thermodynamic chemical evolution. This concept has been proposed earlier by the author (Bassez J Phys: Condens Matter 15:L353-L361, 2003, 2008a, 2008b; Bassez Orig Life Evol Biosph 39(3-4):223-225, 2009; Bassez et al. 2011; Bassezet al. Orig Life Evol Biosph 42(4):307-316, 2012, Bassez 2013) without thermodynamic details. This concept leads to signatures of prebiotic chemistry such as radionuclides and also iron and magnesium carbonates associated with serpentine and/or talc, which were discussed at the 2014 European Astrobiology Network Association conference on Signatures of Life. PMID:25777464

  1. Assessment of two-temperature kinetic model for ionizing air

    Science.gov (United States)

    Park, Chul

    1987-01-01

    A two-temperature chemical-kinetic model for air is assessed by comparing theoretical results with existing experimental data obtained in shock-tubes, ballistic ranges, and flight experiments. In the model, named the TTv model, one temperature (T) is assumed to characterize the heavy-particle translational and molecular rotational energies, and another temperature (Tv) to characterize the molecular vibrational, electron translational, and electronic excitation energies. The theoretical results for nonequilibrium air flow in shock tubes are obtained using the computer code STRAP (Shock-Tube Radiation Program), and for flow along the stagnation streamline in the shock layer over spherical bodies using the newly developed code STRAP (Stagnation-Point Radiation Program). Substantial agreement is shown between the theoretical and experimental results for relaxation times and radiative heat fluxes. At very high temperatures the spectral calculations need further improvement. The present agreement provides strong evidence that the two-temperature model characterizes principal features of nonequilibrium air flow. New theoretical results using the model are presented for the radiative heat fluxes at the stagnation point of a 6-m-radius sphere, representing an aeroassisted orbital transfer vehicle, over a range of free-stream conditions. Assumptions, approximations, and limitations of the model are discussed.

  2. Air pollution model for point source

    International Nuclear Information System (INIS)

    Mathematical models of air pollution have a broad practical application. They are irreplaceable wherever it is not possible to determine a state of air pollution by measuring of a noxious agent concentration. By creating of a suitable model of air pollution we can assess a state of the air quality but we also to predict the pollution that can occur at given atmospheric conditions. The created model is a suitable tool for controlling the activity of TEKO and for the evaluation of the quality of air in a monitored area of the city of Kosice. A sufficient knowledge in the given field is a condition. The input data and information necessary for creating such a model of polluted air is another important factor. (authors)

  3. Air pollution model for point source

    OpenAIRE

    Jozef Mačala; Viliam Carach

    2006-01-01

    Mathematical models of air pollution have a broad practical application. They are irreplaceable wherever it is not possible to determine a state of air pollution by measuring of a noxious agent concentration. By creating of a suitable model of air pollution we can assess a state of the air quality but we also to predict the pollution that can occur at given atmospheric conditions. The created model is a suitable tool for controlling the activity of TEKO and for the evaluation of the quality o...

  4. Is cosmic radiation exposure of air crew amenable to control?

    International Nuclear Information System (INIS)

    ICRP Committee 4 currently has a Working Party on Cosmic Ray Exposure in Aircraft and Space Flight. It has assembled information on doses arising in aircraft and space flight and considered the appropriateness of the Commission's recommendations relating to air crew. A central issue is whether the exposures received should be considered amenable to control. Factors of relevance to the enhanced cosmic radiation exposure of air crew, and frequent fliers such as couriers, are doses to pregnant staff, the issue of controllability of doses, and the implementation of regulatory controls. It is concluded that while air crew in the current range of subsonic jet aircraft are exposed to enhanced levels of cosmic radiation, these exposures are not readily controllable nor likely to exceed about 6 mSv/y. The revised ICRP Recommendations in 1991 (ICRP 60) propose air crew be designated as occupationally exposed. However, none of the usual optimisation of dose actions associated with regulation of practices, such as classification of work areas and rules governing working procedures, can be implemented, and in practice the doses are not amenable to control. The International Basic Safety Standards therefore leave this designation to the judgement of national regulatory authorities. One requirement that stems from designation as occupational exposure is that of restriction of doses to pregnant women. Both from the points of view that it is questionable whether exposure of air crew can reasonably be considered to be amenable to control, and the magnitude of the risks from exposures incurred, there is little reason to invoke additional restrictions to limit exposures of pregnant air crew. Copyright (1999) Australasian Radiation Protection Society Inc

  5. [Radiation exposure and air quality aboard commercial airplanes].

    Science.gov (United States)

    Bergau, L

    1999-10-01

    The amount of exposure to cosmic radiation during air travel is next to a number of additional factors mainly dependent on the flight level of the aircraft. Flying in an altitude of 41,000 feet equaling 12,800 meters the amount of radiation exposure is of course considerable higher than on the ground. The overall exposure of flying personnel to cosmic radiation flying about 600-700 hours per year can be estimated between 3 and 6 mSv (300-600 mrem). According to the flight hours of passengers, the radiation exposure is much lower and can be neglected for most of the travelers final judgement about the possible risks for flying personnel as far as a higher incident of malignant tumors is concerned has not jet been finally made. Talking of cabin air quality compromises have to be made and thus the well-being of the passengers can be negatively influenced. Air pressure and oxygen partial pressure correspond to an altitude of 2400 meters (8,000 feet) above sea level with possible consequences to the cardiopulmonary system. Increased level of ozone can lead to respiratory problems of the upper airways, increased carbon dioxide may cause hyperventilation. The mucous membranes of the respiratory tract are dried out due to the extremely low humidity of the cabin air. Smoking during flight results in an increase of the nicotine blood levels even in passengers sitting in the non-smoking areas. In modern aircraft the fresh-air flow cannot be regulated individually any more, this may lead to an insufficient circulation of used air in relation to fresh air and could cause the phenomena of hanging smoke. There has always been the idea that there is an increased risk for passengers for acquiring infectious diseases. However this is not the case. Modern HEPA-filter prevent an accumulation even of the smallest particles including bacteria and viruses within the recirculation flow in the cabin air. The overall risk of getting an infectious disease is significantly lower than in other ground operated public means of transportation. PMID:10568250

  6. Overview of Radiation Belt Modelling

    Science.gov (United States)

    Heynderickx, D.

    The Earth's trapped radiation belts were discovered at the beginning of the space age and were immediately recognised as a considerable hazard to space missions. Consequently, considerable effort was invested in building models of the trapped proton and electron populations, culminating in the NASA AP-8 and AE-8 models which have been the de facto standards since the seventies. The CRRES mission has demonstatred that the trapped radiation environment is much more complex than the static environment described by the old models. Spatial and especially temporal variations were shown to be much more important than previously thought, and to require more complex models than those in use at that time. Such models are now becoming available, but they are limited in spatial or temporal coverage, and no global, dynamic, trapped radiation belt model is forthcoming. It is therefore vital to co-ordinate future modelling efforts in order to develop new standard models.

  7. Relativistic Model for Radiating Star

    Science.gov (United States)

    Tewari, B. C.

    2006-12-01

    New Solution of Einstein’s equations for spherically symmetric radiating fluid distribution has been presented. The solution is used to construct a model of radiating star. The interior space-time metric is matched with Vaidya exterior metric at zero pressure boundary.

  8. Cosmic radiation exposure survey of an Air Force Transport Squadron

    International Nuclear Information System (INIS)

    A combination of in-flight measurements and calculations from the predictive code for aircrew radiation exposure (PCAire) was used to assess the cosmic radiation conditions for a Transport Squadron in the Canadian Air Force. The equipment suite from the Royal Military College of Canada, including a TEPC and bubble detectors, were flown over a sampling of air routes while the survey of the Squadron members covered a 2 year period over the recent solar minimum and, thus, maximum radiation conditions. Various comparisons were made between the measurements and calculations to confirm the results of this work. For this period, more than half received more than the general public limit of 1 mSv per year and most received 0.5 or 2.5 mSv, with some receiving almost 4 mSv. This wide variation reflected the varied nature of their deployments. - Highlights: ? Aircrew of a Transport Squadron were surveyed for cosmic radiation exposure. ? A semi-empirical code, PCAire, was used for the first time to conduct this survey. ? Simultaneous in-flight measurements were undertaken on many flights. ? The measurements and survey results were consistent throughout the study. ? The study was conducted during a cosmic radiation peak in the solar cycle

  9. Large Scale Computations in Air Pollution Modelling

    DEFF Research Database (Denmark)

    Zlatev, Z.; Brandt, J.; Builtjes, P. J. H.; Carmichael, G.; Dimov, I.; Dongarra, J.; Dop, H. van; Georgiev, K.; Hass, H.

    Proceedings of the NATO Advanced Research Workshop on Large Scale Computations in Air Pollution Modelling, Sofia, Bulgaria, 6-10 July 1998......Proceedings of the NATO Advanced Research Workshop on Large Scale Computations in Air Pollution Modelling, Sofia, Bulgaria, 6-10 July 1998...

  10. Considerations on the microwave radiation emitted by extended air showers

    CERN Document Server

    Conti, E

    2015-01-01

    The emission of microwave radiation by extended air showers produced by high energy cosmic rays has been investigated for more than half a century. We discuss the expected emitted power as a function of the cosmic ray energy and of the microwave frequency, for both coherent and incoherent emission mechanisms. We show that the available experimental data are not sufficient to clearly identify the emission mechanisms and quantify the emission yield. We infer that the bremsstralhung radiation emission could be exploited for the detection of astronomical $\\gamma$-rays with energy above 10 GeV in the 1-10 GHz frequency range, and propose an experimental scheme to verify such idea.

  11. Preclinical models in radiation oncology

    International Nuclear Information System (INIS)

    As the incidence of cancer continues to rise, the use of radiotherapy has emerged as a leading treatment modality. Preclinical models in radiation oncology are essential tools for cancer research and therapeutics. Various model systems have been used to test radiation therapy, including in vitro cell culture assays as well as in vivo ectopic and orthotopic xenograft models. This review aims to describe such models, their advantages and disadvantages, particularly as they have been employed in the discovery of molecular targets for tumor radiosensitization. Ultimately, any model system must be judged by its utility in developing more effective cancer therapies, which is in turn dependent on its ability to simulate the biology of tumors as they exist in situ. Although every model has its limitations, each has played a significant role in preclinical testing. Continued advances in preclinical models will allow for the identification and application of targets for radiation in the clinic

  12. Mathematical Models for Room Air Distribution - Addendum

    DEFF Research Database (Denmark)

    Nielsen, Peter V.

    A number of different models on the air distribution in rooms are introduced. This includes the throw model, a model on penetration length of a cold wall jet and a model for maximum velocity in the dimensioning of an air distribution system in highly loaded rooms and shows that the amount of heat...... duct systems are given and the paper is concluded by mentioning a computer-based prediction method which gives the velocity and temperature distribution in the whole room....

  13. Mathematical Models for Room Air Distribution

    DEFF Research Database (Denmark)

    Nielsen, Peter V.

    A number of different models on the air distribution in rooms are introduced. This includes the throw model, a model on penetration length of a cold wall jet and a model for maximum velocity in the dimensioning of an air distribution system in highly loaded rooms and shows that the amount of heat...... duct systems are given and the paper is concluded by mentioning a computer-based prediction method which gives the velocity and temperature distribution in the whole room....

  14. How to model radiation carcinogenesis

    International Nuclear Information System (INIS)

    Problems encountered in modelling radiation carcinogenesis are examined in the light of the available experimental information and discussed in view of existing attempts. The role of endogenous and exogenous factors is considered. (author)

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

    International Nuclear Information System (INIS)

    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 efficient 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 efficient 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

  16. Ultraviolet radiation and air contamination during total hip replacement

    International Nuclear Information System (INIS)

    Ultraviolet (uv) radiation of the operating room was assessed bacteriologically in an open randomized study of 30 total hip procedures. Volumetric air-sampling demonstrated that the number of colony forming units (cfu m-3) were significantly reduced (P less than 0.001) by uv light, both close to the wound and in the periphery of the operating room. No adverse effects of the uv-irradiation were observed either in the patients or the staff. In operating rooms fitted with a zonal ventilation system and with an air change rate of about 70 h-1, the addition of uv irradiation during surgery may achieve ultra clean air. However, in conventionally ventilated operating rooms uv-irradiation alone is probably not sufficient to do so

  17. Models of diffuse solar radiation

    Energy Technology Data Exchange (ETDEWEB)

    Boland, John; Ridley, Barbara [Centre for Industrial and Applied Mathematics, University of South Australia, Mawson Lakes Boulevard, Mawson Lakes, SA 5095 (Australia); Brown, Bruce [Department of Statistics and Applied Probability, National University of Singapore, Singapore 117546 (Singapore)

    2008-04-15

    For some locations both global and diffuse solar radiation are measured. However, for many locations, only global is measured, or inferred from satellite data. For modelling solar energy applications, the amount of radiation on a tilted surface is needed. Since only the direct component on a tilted surface can be calculated from trigonometry, we need to have diffuse on the horizontal available. There are regression relationships for estimating the diffuse on a tilted surface from diffuse on the horizontal. Models for estimating the diffuse radiation on the horizontal from horizontal global that have been developed in Europe or North America have proved to be inadequate for Australia [Spencer JW. A comparison of methods for estimating hourly diffuse solar radiation from global solar radiation. Sol Energy 1982; 29(1): 19-32]. Boland et al. [Modelling the diffuse fraction of global solar radiation on a horizontal surface. Environmetrics 2001; 12: 103-16] developed a validated model for Australian conditions. We detail our recent advances in developing the theoretical framework for the approach reported therein, particularly the use of the logistic function instead of piecewise linear or simple nonlinear functions. Additionally, we have also constructed a method, using quadratic programming, for identifying values that are likely to be erroneous. This allows us to eliminate outliers in diffuse radiation values, the data most prone to errors in measurement. (author)

  18. Air quality modeling in Warsaw Metropolitan Area

    OpenAIRE

    Piotr Holnicki; Zbigniew Nahorski

    2013-01-01

    Decision support of air quality management needs to connect several categories of the input data with the analytical process of air pollution dispersion. The aim of the respective model of air pollution is to provide a quantitative assessment of environmental impact of emission sources in a form of spatial/temporal maps of pollutants’ concentration or deposition in the domain. These results are in turn used in assessment of environmental risk and supporting respective planning actions. Howeve...

  19. OpenAIRE Data Model Specification

    OpenAIRE

    2012-01-01

    The OpenAIRE web site will offer functionalities for administrators, anonymous and registered users to manage an Information Space of FP7-funded open access publications. The aim of this document is to describe the conceived structure and semantics of this Information Space, i.e., the Open AIRE data model, by providing an abstract definition of its main entities and the relationships between them. In this definitional process, the intended interaction (Task 7.2) between the OpenAIRE Informati...

  20. To the air crew exposure to cosmic radiation

    International Nuclear Information System (INIS)

    To analyse air crew exposure to cosmic radiation, both experimentally and by means of the calculation with the goal to assure the individual assessment of this type of exposure. The experimental measurements were realised by means of several different equipments, both passive and active, to characterise all components of radiation fields on board aircraft. The calibration experiments in the on-Earth high energy particle reference fields were also regularly repeated since 1993. The most of measurements was performed in the periods between 1991 and 1993, and, subsequently, during 1999. The calculation of air crew exposure level on board was performed by means of the transport code CARI, in the versions 3N (H*(10)-ambient dose equivalent is calculated), and/or 5E (E-effective dose is calculated). The experimental data directly measured in the period 1991 to 1993 were interpreted on the base of a detector energy response, the results of calibration experiments in high energy reference fields and, also, taking into account independent data on particle's energy spectra and their energy deposition in the human body. Complete set of data obtained in the period mentioned was treated using a regression analysis to get the generalised dependence of exposure level on the flight altitude in the period of rather low solar activity. The experimental data directly measured during the series realised during 1999 were interpreted in the same way and they were compared with the data calculated for the same flight profile by means of the code CARI in its version 5E. It was found that the experimental data are in both cases about 20-25% higher than the calculated ones. The experimentally measured ambient dose equivalent rate vary between 4 and 8 μSv per hour for flight altitudes between 10 and 13 km. The code CARI 5E was also used to estimate the annual exposure of the air crew of a small company for the year 1998. Some model assumptions concerning the flight altitudes distributions have been adopted, their influence would compensate the underestimation observed when calculated values are compared with the experimental ones. It was found that, for the average number of flight hours about 450, three maxima can be distinguished in the effective dose distribution. The highest one (about 2.5 mSv) corresponds to the personnel flying frequently on northatlantic flights. The average annual effective dose was 1.54 mSv, when exposures below 1 mSv are omitted, it decreases to 1.85 mSv. Both figures are higher than it is usual for the most of other categories of occupationally exposed persons. We believe that the estimated values of effective doses are correct within ±25%, which fulfill the requirements on a personal dosimetry system. Both calculation and experimental approaches can be improved, we continue our effort in both directions. (author)

  1. Drying Strategy of Shrimp using Hot Air Convection and Hybrid Infrared Radiation/Hot Air Convection

    Directory of Open Access Journals (Sweden)

    Supawan TIRAWANICHAKUL

    2008-01-01

    Full Text Available The main objective of the research was to study the effect of drying temperatures using infrared irradiation and electric heating convection on dehydration and was to investigate the effect of drying conditions on the quality of the shrimp. Two sizes of fresh shrimp (100 shrimp/kg and 200 shrimp/kg with initial moisture content of 270 - 350 % dry-basis were dried under various conditions while the final moisture content of dried shrimp was in ranges between 20 and 25 % dry-basis. Hot air flow rates of 1.0 -   1.2 m/s, drying temperatures of 40 - 90 °C and infrared intensities of 1,785.7 - 3,571.4 W/m2 were used in these experiments. The experimental results showed that the rate of moisture content transfer of both sizes of shrimps decreased exponentially with drying time while increasing drying temperature significantly affected to the drying kinetics and quality of the shrimps. Effective diffusion coefficients of both shrimps were determined by a diffusion model forming a finite cylindrical shape was in order of 10-7 m2/s and this effective diffusion coefficient value was relatively dependent on the drying temperature compared to the initial moisture content. The quality analysis of dried shrimp using an infrared source and electric heating source found that the redness value (Hunter a-value of dried samples using hybrid infrared radiation and electric heating had a higher colour uniformity than other drying methods. Additionally, shrinkage and rehydration properties were insignificantly different for all drying strategies (p < 0.05 and drying using infrared radiation had higher drying rates compared to electric heat convection, corresponding to relatively low drying times.

  2. Alleviating operating temperature of concentration solar cell by air active cooling and surface radiation

    International Nuclear Information System (INIS)

    In the present paper, a heat transfer model for a multi-junction concentrating solar cell system has been developed. The model presented in this work includes the GaInP/GaAs/Ge triple-junction solar cell with a ventilation system in which air is forced to flow within a duct behind the solar cell assembly and its holders and accessories (anti-reflective glass cover, adhesive material, and aluminum back plate). A mathematical model for the entire system is presented and the finite difference technique has been used to solve the governing equations. Results showed that the interaction of surface radiation and air convection could adequately cool the solar cell at medium concentration ratios. For high concentration ratios, the channel width would need to be narrowed to micro-meter values to maintain the required efficiency of cooling. The conjugation effect has been shown to be significant and has a noticeable effect on the maximum solar cell temperature. Furthermore, the air inlet velocity and channel width were also found to have major effects on the cell temperature. -- Highlights: A model has been developed to predict the solar cell temperature cooling by air. Cell temperature can be remarkably reduced with the presence of surface radiation. Cell temperature is extremely dependent on air inlet velocity and channel width. Conjugation effect has a noticeable effect on the maximum solar cell temperature

  3. Impact of inherent meteorology uncertainty on air quality model predictions

    Science.gov (United States)

    Gilliam, Robert C.; Hogrefe, Christian; Godowitch, James M.; Napelenok, Sergey; Mathur, Rohit; Rao, S. Trivikrama

    2015-12-01

    It is well established that there are a number of different classifications and sources of uncertainties in environmental modeling systems. Air quality models rely on two key inputs, namely, meteorology and emissions. When using air quality models for decision making, it is important to understand how uncertainties in these inputs affect the simulated concentrations. Ensembles are one method to explore how uncertainty in meteorology affects air pollution concentrations. Most studies explore this uncertainty by running different meteorological models or the same model with different physics options and in some cases combinations of different meteorological and air quality models. While these have been shown to be useful techniques in some cases, we present a technique that leverages the initial condition perturbations of a weather forecast ensemble, namely, the Short-Range Ensemble Forecast system to drive the four-dimensional data assimilation in the Weather Research and Forecasting (WRF)-Community Multiscale Air Quality (CMAQ) model with a key focus being the response of ozone chemistry and transport. Results confirm that a sizable spread in WRF solutions, including common weather variables of temperature, wind, boundary layer depth, clouds, and radiation, can cause a relatively large range of ozone-mixing ratios. Pollutant transport can be altered by hundreds of kilometers over several days. Ozone-mixing ratios of the ensemble can vary as much as 10-20 ppb or 20-30% in areas that typically have higher pollution levels.

  4. Heating, ventilation and air conditioning system modelling

    Energy Technology Data Exchange (ETDEWEB)

    Whalley, R.; Abdul-Ameer, A. [British University in Dubai (United Arab Emirates)

    2011-03-15

    Heating, ventilation and air conditioning modelling methods, for large scale, spatially dispersed systems are considered. Existing techniques are discussed and proposals for the application of novel analysis approaches are outlined. The use of distributed-lumped parameter procedures enabling the incorporation of the relatively concentrated and significantly dispersed, system element characteristics, is advocated. A dynamic model for a heating, ventilation and air conditioning system comprising inlet and exhaust fans, with air recirculation, heating/cooling and filtration units is presented. Pressure, airflow and temperature predictions within the system are computed following input, disturbance changes and purging operations. The generalised modelling advancements adopted and the applicability of the model for heating, ventilation and air conditioning system simulation, re-configuration and diagnostics is emphasised. The employment of the model for automatic, multivariable controller design purposes is commented upon. (author)

  5. Multi-Group Reductions of LTE Air Plasma Radiative Transfer in Cylindrical Geometries

    Science.gov (United States)

    Scoggins, James; Magin, Thierry Edouard Bertran; Wray, Alan; Mansour, Nagi N.

    2013-01-01

    Air plasma radiation in Local Thermodynamic Equilibrium (LTE) within cylindrical geometries is studied with an application towards modeling the radiative transfer inside arc-constrictors, a central component of constricted-arc arc jets. A detailed database of spectral absorption coefficients for LTE air is formulated using the NEQAIR code developed at NASA Ames Research Center. The database stores calculated absorption coefficients for 1,051,755 wavelengths between 0.04 µm and 200 µm over a wide temperature (500K to 15 000K) and pressure (0.1 atm to 10.0 atm) range. The multi-group method for spectral reduction is studied by generating a range of reductions including pure binning and banding reductions from the detailed absorption coefficient database. The accuracy of each reduction is compared to line-by-line calculations for cylindrical temperature profiles resembling typical profiles found in arc-constrictors. It is found that a reduction of only 1000 groups is sufficient to accurately model the LTE air radiation over a large temperature and pressure range. In addition to the reduction comparison, the cylindrical-slab formulation is compared with the finite-volume method for the numerical integration of the radiative flux inside cylinders with varying length. It is determined that cylindrical-slabs can be used to accurately model most arc-constrictors due to their high length to radius ratios.

  6. Portable radiation meters evaluation in high rates of air kerma

    Energy Technology Data Exchange (ETDEWEB)

    Damatto, Willian B.; Potiens, Maria da Penha A.; Vivolo, Vitor, E-mail: wbdamatto@ipen.br, E-mail: mppotiens@ipen.br, E-mail: vivolo@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    A set of portable meters of ionizing radiation high rates of air kerma (teletectors) commonly used in emergencies in Brazil and sent to the Calibration Laboratory of IPEN were under several tests and analyst is parameters for the detectors behavior were established, specifying their sensitivities and operating characteristics. Applied tests were: reading equipment variation with battery voltage, geotropism effect, energy dependence, the angular dependence and overload. Thus it was possible to determine the most common characteristic found in these equipment (quality control programs). The behavior of 17 portable meters was analyzed and in this study, 10 of them have been tested. It was performed to characterize the gamma irradiating system (radiation dosimetry field) that possesses higher activity in teletectors for testing of larger measuring range. New calibration criteria were established following international recommendations. Therefore, it was made the improvement of the quality control programme of portable meters of ionizing radiation high rates of air kerma calibration laboratory, benefiting the users of such equipment with better consistent calibration measurements. (author)

  7. Surface Flux Modeling for Air Quality Applications

    Directory of Open Access Journals (Sweden)

    Limei Ran

    2011-08-01

    Full Text Available For many gasses and aerosols, dry deposition is an important sink of atmospheric mass. Dry deposition fluxes are also important sources of pollutants to terrestrial and aquatic ecosystems. The surface fluxes of some gases, such as ammonia, mercury, and certain volatile organic compounds, can be upward into the air as well as downward to the surface and therefore should be modeled as bi-directional fluxes. Model parameterizations of dry deposition in air quality models have been represented by simple electrical resistance analogs for almost 30 years. Uncertainties in surface flux modeling in global to mesoscale models are being slowly reduced as more field measurements provide constraints on parameterizations. However, at the same time, more chemical species are being added to surface flux models as air quality models are expanded to include more complex chemistry and are being applied to a wider array of environmental issues. Since surface flux measurements of many of these chemicals are still lacking, resistances are usually parameterized using simple scaling by water or lipid solubility and reactivity. Advances in recent years have included bi-directional flux algorithms that require a shift from pre-computation of deposition velocities to fully integrated surface flux calculations within air quality models. Improved modeling of the stomatal component of chemical surface fluxes has resulted from improved evapotranspiration modeling in land surface models and closer integration between meteorology and air quality models. Satellite-derived land use characterization and vegetation products and indices are improving model representation of spatial and temporal variations in surface flux processes. This review describes the current state of chemical dry deposition modeling, recent progress in bi-directional flux modeling, synergistic model development research with field measurements, and coupling with meteorological land surface models.

  8. Radio Emission from Cosmic Ray Air Showers: Coherent Geosynchrotron Radiation

    CERN Document Server

    Huege, T; Huege, Tim; Falcke, Heino

    2003-01-01

    Cosmic ray air showers have been known for over 30 years to emit pulsed radio emission in the frequency range from a few to a few hundred MHz, an effect that offers great opportunities for the study of extensive air showers with upcoming fully digital "software radio telescopes" such as LOFAR and the enhancement of particle detector arrays such as KASCADE Grande or the Pierre Auger Observatory. However, there are still a lot of open questions regarding the strength of the emission as well as the underlying emission mechanism. Accompanying the development of a LOFAR prototype station dedicated to the observation of radio emission from extensive air showers, LOPES, we therefore take a new approach to modeling the emission process, interpreting it as "coherent geosynchrotron emission" from electron-positron pairs gyrating in the earth's magnetic field. We develop our model in a step-by-step procedure incorporating increasingly realistic shower geometries in order to disentangle the coherence effects arising from...

  9. Calculation of molecular bremsstrahlung radiation and air shower plasma conditions for CROME

    International Nuclear Information System (INIS)

    The possibility of the detection of extensive air showers by observation of isotropic microwave radiation due to molecular bremsstrahlung has been proposed in 2008. Ionization electrons, forming a short-lived, tenuous plasma in the wake of the shower, interact with atmospheric neutrals and produce bremsstrahlung. Concurrent with first measurements of microwave radiation by the CROME experiment in Karlsruhe, an independent, theory based model for emission of isotropic bremsstrahlung emission has been developed. In this talk, the assumptions of the model for bremsstrahlung emission and the findings concerning the state of the plasma in an air shower are discussed. The magnitude of the expected signal is calculated and compared to predictions made in the original proposal by Gorham et al. and to the observed GHz signals.

  10. Calculation of molecular bremsstrahlung radiation and air shower plasma conditions for CROME

    Energy Technology Data Exchange (ETDEWEB)

    Neunteufel, Patrick; Engel, Ralph; Smida, Radomir; Werner, Felix [Karlsruher Institut fuer Technologie (Germany)

    2013-07-01

    The possibility of the detection of extensive air showers by observation of isotropic microwave radiation due to molecular bremsstrahlung has been proposed in 2008. Ionization electrons, forming a short-lived, tenuous plasma in the wake of the shower, interact with atmospheric neutrals and produce bremsstrahlung. Concurrent with first measurements of microwave radiation by the CROME experiment in Karlsruhe, an independent, theory based model for emission of isotropic bremsstrahlung emission has been developed. In this talk, the assumptions of the model for bremsstrahlung emission and the findings concerning the state of the plasma in an air shower are discussed. The magnitude of the expected signal is calculated and compared to predictions made in the original proposal by Gorham et al. and to the observed GHz signals.

  11. Biophysical models in radiation biology

    International Nuclear Information System (INIS)

    Models serve a variety of purposes: to link physics and biology; to interpolate and extrapolate to dose regions where direct biological measurements of statistical significance are not feasible; to address basic mechanisms; to suggest new experiments designed to test hypotheses predicted by the model. In the past, the modeling arena has been dominated by dose-response curves for cell killing which have slowly but surely incorporated more and more of the biological factors that are known to be important. At the present time, the modelers urgently need to follow the revolution in the new biology as quantitative data become available. There are several areas involved: i. the relation between DNA strand breaks, initial breaks as measured by the premature chromosome condensation technique and cell lethality. ii. modeling of oncogenic transformation as a function of dose and of radiation quality. iii. modeling of oncogenic transformation as a function of oncogene activation. iv. modeling of oncogene activation and suppressor cell deletion as a function of radiation dose and radiation quality. (author)

  12. Hadronic interaction models and air shower simulations

    International Nuclear Information System (INIS)

    Extensive air showers can only be interpreted by comparison of the measured observables with simulations, using a suitable model for the shower development in the atmosphere. Due to the complexity of the phenomenon, in the past the models were quite simple and results from air showers were to interpret qualitatively, at best. With a new generation of experiments more advanced detectors became operational and the need for detailed simulations grew. In recent years several new air shower programs were developed. Using the rapid increase of the computing power they have now reached a high level of sophistication. Particle transport, electromagnetic interactions and decay of unstable particles are treated in great detail. However the most crucial ingredient to all these programs is the modeling of hadronic interactions since it requires extrapolation in energy, primary mass and kinematics to regions where no accelerator data exist and where theoretical guidelines are only vague. As a consequence of the model uncertainties, experiments using different models occasionally reached very different conclusions on energy spectra and composition of the cosmic rays. CORSIKA is an extensive air shower simulation program that contains five different hadronic interaction models (VENUS, QGSJET, SIBYLL, HDPM, and DPMJET). It is widely used throughout the cosmic ray community and allows the study of model dependencies and the systematic effects of measurement and event reconstruction. Results for different models concerning inelastic cross-sections and particle production and their influence on air shower variables are discussed and the systematic uncertainties for air shower analyses are investigated. The capability of precise multi-parameter measurements to discriminate between the models is emphasised

  13. Scatter radiation and the effects of air gaps in cephalometric radiography

    International Nuclear Information System (INIS)

    The scatter radiation and scatter rejection effect of air gaps in cephalometric radiography were evaluated using an effective scatter point source (ESPS) model. A 16-cm-thick water-equivalent phantom was used to measure the scatter fraction. The distance from the source to the center of the object (SOD) was 150, 200, or 300 cm. The air gap was varied from 0 to 96 cm for each SOD. A photostimulable phosphor plate was used as the X-ray sensor. The measured scatter fraction ESPS model was used to simulate the scatter rejection by the air gap, and the predictions were compared with the grid. There was excellent agreement between the ESPS model and the scatter measurements. The air gap reduced the scatter radiation, especially for an SOD of 200 or 300 cm, while keeping an object magnification of 1.1 in view of the signal-to-noise ratio improvement factor. The results suggest that a grid should not be used in cephalometric radiography. (author)

  14. A branching model for hadronic air showers

    CERN Document Server

    Novotny, Vladimir; Ebr, Jan

    2015-01-01

    We introduce a simple branching model for the development of hadronic showers in the Earth's atmosphere. Based on this model, we show how the size of the pionic component followed by muons can be estimated. Several aspects of the subsequent muonic component are also discussed. We focus on the energy evolution of the muon production depth. We also estimate the impact of the primary particle mass on the size of the hadronic component. Even though a precise calculation of the development of air showers must be left to complex Monte Carlo simulations, the proposed model can reveal qualitative insight into the air shower physics.

  15. Portable Radio-Controlled Air Sampler and Environmental Radiation Monitor

    International Nuclear Information System (INIS)

    The destructive testing of prototype nuclear devices at the United States Atomic Energy Commission's Test Sites and the possible release of radioactive effluent to the atmosphere, necessitates capability in sampling and analysis of these effluents. Understanding of the destruction mechanism, air transport and deposition phenomena as well as an evaluation of the potential hazard to the surrounding population can be gained by a study of gross gamma measurements, nuclides released and particle-size distribution. The acquisition of these fundamental data frequently takes hundreds of man hours to transport, locate and operate power sources of the engine-generator type, laboratory instrumentation and air-sampling devices on a downwind grid from the test site. The sophisticated laboratory equipment normally used is ill suited to rough handling over poor access roads and operation in the severe climatic environment routinely encountered in the test areas. The problems and time associated with the start-up of many tens of these instrumentation systems and the uncertainty in time of the test release due to varying wind parameters are an added inducement for improved hardware and procedures. A portable battery-powered monitoring system has been designed to detect and record pre-test and post-test beta-gamma radiation levels and the radioactivity build-up and decay on an air sampler filter. The capability exists for the remote ON-OFF switching of the air sampler by radio signal. The entire electronic system is housed in an aluminum carrying case with the electronics sealed from moisture and dust contamination. The remote switching concept used provides for 1438 individual control functions or 46 group control functions depending upon the address frequencies selected. The satisfactory operation of the remote control feature is limited only by the path distance over which the radio control link will function. Two channels of radiation data are permanently recorded on a pressure-sensitive chart and are responsive over a 4-decade range from 0.01 mR/h to 100 mR/h gross beta-gamma levels. Normal battery power provides up to 1 hours operation for a high-capacity air sampler of the Staplex type or more extended operation with less power demanding samplers or other instrumentation. (author)

  16. Modeling monthly mean air temperature for Brazil

    Science.gov (United States)

    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.

  17. An air quality model for Central Mexico

    International Nuclear Information System (INIS)

    A computational air quality model for Central Mexico that includes the Basin of the Valley of Mexico, the Valleys of Toluca, Puebla and Cuernavaca already in experimental operation, is presented. The meteorology of the region is obtained combining two non-hydrostatic models: a model designed for synoptic scales called MM5 provides initial and boundary data to a model specially designed for urban environments and scales called MEMO. The transport model used numerical techniques developed by the authors that eliminate numerical diffusion and dispersion. For the photochemical model several ODE's integrators were tested. The emissions model developed uses the latest inventory data gathered in the region. (Author)

  18. Validation of the community radiative transfer model

    International Nuclear Information System (INIS)

    To validate the Community Radiative Transfer Model (CRTM) developed by the U.S. Joint Center for Satellite Data Assimilation (JCSDA), the discrete ordinate radiative transfer (DISORT) model and the line-by-line radiative transfer model (LBLRTM) are combined in order to provide a reference benchmark. Compared with the benchmark, the CRTM appears quite accurate for both clear sky and ice cloud radiance simulations with RMS errors below 0.2 K, except for clouds with small ice particles. In a computer CPU run time comparison, the CRTM is faster than DISORT by approximately two orders of magnitude. Using the operational MODIS cloud products and the European Center for Medium-range Weather Forecasting (ECMWF) atmospheric profiles as an input, the CRTM is employed to simulate the Atmospheric Infrared Sounder (AIRS) radiances. The CRTM simulations are shown to be in reasonably close agreement with the AIRS measurements (the discrepancies are within 2 K in terms of brightness temperature difference). Furthermore, the impact of uncertainties in the input cloud properties and atmospheric profiles on the CRTM simulations has been assessed. The CRTM-based brightness temperatures (BTs) at the top of the atmosphere (TOA), for both thin (τ30) clouds, are highly sensitive to uncertainties in atmospheric temperature and cloud top pressure. However, for an optically thick cloud, the CRTM-based BTs are not sensitive to the uncertainties of cloud optical thickness, effective particle size, and atmospheric humidity profiles. On the contrary, the uncertainties of the CRTM-based TOA BTs resulting from effective particle size and optical thickness are not negligible in an optically thin cloud.

  19. Solar radiation estimation using sunshine hour and air pollution index in China

    International Nuclear Information System (INIS)

    Highlights: • Aerosol can affect coefficients of A–P equation to estimate solar radiation. • Logarithmic model performed best, according to MBE, MABE, MPE, MAPE, RMSE and NSE. • Parameters of A–P model can be adjusted by API, geographical position and altitude. • A general equation to estimate solar radiation was established in China. - Abstract: Angström–Prescott (A–P) equation is the most widely used empirical relationship to estimate global solar radiation from sunshine hours. A new approach based on Air Pollution Index (API) data is introduced to adjust the coefficients of A–P equation in this study. Based on daily solar radiation, sunshine hours and API data at nine meteorological stations from 2001 to 2011 in China, linear, exponential and logarithmic models are developed and validated. When evaluated by performance indicators of mean bias error, mean absolute bias error, mean percentage error, mean absolute percentage error, root mean square error, and Nash–Sutcliffe Equation, it is demonstrated that logarithmic model performed better than the other models. Then empirical coefficients for three models are given for each station and the variations of these coefficients are affected by API, geographical position, and altitude. This indicates that aerosol can play an important role in estimation solar radiation from sunshine hours, especially in those highly polluted regions. Finally, a countrywide general equation is established based on the sunshine hour data, API and geographical parameters, which can be used to estimate the daily solar radiation in areas where the radiation data is not available

  20. Slot Region Radiation Environment Models

    Science.gov (United States)

    Sandberg, Ingmar; Daglis, Ioannis; Heynderickx, Daniel; Evans, Hugh; Nieminen, Petteri

    2013-04-01

    Herein we present the main characteristics and first results of the Slot Region Radiation Environment Models (SRREMs) project. The statistical models developed in SRREMs aim to address the variability of trapped electron and proton fluxes in the region between the inner and the outer electron radiation belt. The energetic charged particle fluxes in the slot region are highly dynamic and are known to vary by several orders of magnitude on both short and long timescales. During quiet times, the particle fluxes are much lower than those found at the peak of the inner and outer belts and the region is considered benign. During geospace magnetic storms, though, this region can fill with energetic particles as the peak of the outer belt is pushed Earthwards and the fluxes can increase drastically. There has been a renewed interest in the potential operation of commercial satellites in orbits that are at least partially contained within the Slot Region. Hence, there is a need to improve the current radiation belt models, most of which do not model the extreme variability of the slot region and instead provide long-term averages between the better-known low and medium Earth orbits (LEO and MEO). The statistical models developed in the SRREMs project are based on the analysis of a large volume of available data and on the construction of a virtual database of slot region particle fluxes. The analysis that we have followed retains the long-term temporal, spatial and spectral variations in electron and proton fluxes as well as the short-term enhancement events at altitudes and inclinations relevant for satellites in the slot region. A large number of datasets have been used for the construction, evaluation and inter-calibration of the SRREMs virtual dataset. Special emphasis has been given on the use and analysis of ESA Standard Radiation Environment Monitor (SREM) data from the units on-board PROBA-1, INTEGRAL, and GIOVE-B due to the sufficient spatial and long temporal coverage of the slot region. In addition, other datasets such as EI/AZUR, MEA/CRRES, ERMD/XMM also have been considered and processed. The output of the models provides mean and peak energetic particle fluxes for a given mission duration as determined by confidence levels for different time scales. Validation studies and comparison with standard radiation belt models, such as AE8-AP8 have been also performed. The SRREMs project has been commissioned by ESA/ESTEC through contract 4000104839.

  1. On radiofrequency component of transition radiation of extensive air shower

    International Nuclear Information System (INIS)

    The mechanism of radio emission caused by the transition radiation of the contrarily charged particles of the expensive air shower in the magnetic field of the Earth is studied for the first time. It is established that for the showers with the energy about 1022 eV the maximum stage whereof is reached at the sea level the electrical field voltage constitutes 60 μV/m MHz at the distance of 500 km from the shower axis. The spectrum intensity maximum is in the area corresponding to the atmospheric disturbances minimum (∼ 1 μHz). These conditions stimulate the formulation of the experiment on the high-energy cosmic ray radio detection, the scheme whereof is proposed in this work

  2. Nanodiamond formation via thermal radiation from an air shock

    Science.gov (United States)

    de Carli, Paul

    2013-06-01

    Nanodiamonds have recently been found in sediments of Younger Dryas age, about 12,900 years ago. Carbon isotope ratios imply that the source of carbon was terrestrial organic matter and rule out the possibility that the diamond was of cosmic origin, e.g., from an influx of meteorites. The nanodiamonds are associated with mineral spherules (and other shapes) that have compositions and textures consistent with the rapid melting and solidification of local soil. The inferred temperatures are much too high for natural events such as forest fires. Similar deposits of nanodiamond have been found in the 65 million year old K-Pg layer associated with the ca. 200 km diameter Chicxulub impact crater. Nanodiamond have also been reported in the vicinity of the Tunguska event, presumed to be the result of an air shock produced by the interaction of a rapidly moving cosmic body with the Earth's atmosphere. We infer that the nanodiamonds were formed when the thermal radiation from the air shock pyrolyzed surface organic matter. Rapid reaction locally depleted the atmosphere of oxygen and the remaining carbon could condense as nanodiamond. A similar mechanism can be invoked to account for the formation of nanodiamond as a froduct of the detonation of ozygen-deficient high explosives.

  3. Estimation of Biomass Burning Influence on Air Pollution around Beijing from an Aerosol Retrieval Model

    OpenAIRE

    Sonoyo Mukai; Masayoshi Yasumoto; Makiko Nakata

    2014-01-01

    We investigate heavy haze episodes (with dense concentrations of atmospheric aerosols) occurring around Beijing in June, when serious air pollution was detected by both satellite and ground measurements. Aerosol retrieval is achieved by radiative transfer simulation in an Earth atmosphere model. We solve the radiative transfer problem in the case of haze episodes by successive order of scattering. We conclude that air pollution around Beijing in June is mainly due to increased emissions of an...

  4. InMAP: a new model for air pollution interventions

    OpenAIRE

    Tessum, C. W.; J. D. Hill; Marshall, J. D.

    2015-01-01

    Mechanistic air pollution models are essential tools in air quality management. Widespread use of such models is hindered, however, by the extensive expertise or computational resources needed to run most models. Here, we present InMAP (Intervention Model for Air Pollution), which offers an alternative to comprehensive air quality models for estimating the air pollution health impacts of emission reductions and other potential interventions. InMAP estimates annual-average ch...

  5. Tracks FAQs: What is Modeled Air Data?

    Centers for Disease Control (CDC) Podcasts

    2011-04-25

    In this podcast, CDC Tracking experts discuss modeled air data. Do you have a question for our Tracking experts? Please e-mail questions to trackingsupport@cdc.gov.  Created: 4/25/2011 by National Center for Environmental Health, Division of Environmental Hazards and Health Effects, Environmental Health Tracking Branch.   Date Released: 4/25/2011.

  6. Ensemble Filtering in Air Quality Models

    Czech Academy of Sciences Publication Activity Database

    Eben, Kryštof; Juruš, Pavel; Resler, Jaroslav; Belda, M.; Pelikán, Emil

    Brno : Masaryk University, 2007 - (Horová, I.; Hřebíček, J.) ISBN 978-80-210-4333-6. [ TIES 2007. Annual Meeting of the International Environmental Society /18./. 16.08.2007-20.08.2007, Mikulov] Institutional research plan: CEZ:AV0Z10300504 Keywords : air quality models * data assimilation * ensemble filtering

  7. Air quality modeling for emergency response applications

    International Nuclear Information System (INIS)

    The three-dimensional diagnostic wind field model (MATHEW) and the particle-in-cell transport and diffusion model (ADPIC) are used by the Atmospheric Release Advisory Capability (ARAC) for real-time assessments of the consequences from accidental releases of radioactivity into the atmosphere. For the dispersion of hazardous heavier-than-air gases, a time-dependent, three-dimensional finite element model (FEM3) is used. These models have been evaluated extensively against a wide spectrum of field experiments involving the release of chemically inert tracers or heavier-than-air gases. The results reveal that the MATHEW/ADPIC models are capable of simulating the spatial and temporal distributions of tracer concentration to within a factor of 2 for 50% of the measured tracer concentrations for near surface releases in relatively flat terrain and within a factor of 2 for 20% of the comparisons for elevated releases in complex terrain. The FEM3 model produces quite satisfactory simulations of the spatial and temporal distributions of heavier-than-air gases, typically within a kilometer of the release point. The ARAC consists of a centralized computerized emergency response system that is capable of supporting up to 100 sites and providing real-time predictions of the consequence of transportation accidents that may occur anywhere. It utilizes pertinent accident information, local and regional meteorology, and terrain as input to the MATHEW/ADPIC models for the consequence analysis. It has responded to over 150 incidents and exercises over the past decade

  8. Radiation shielding is not a solution. Radiation protection of air crews

    Energy Technology Data Exchange (ETDEWEB)

    Boehm, Theresia [Vereinigung Cockpit e.V., Frankfurt am Main (Germany). AG Strahlenschutz

    2012-06-15

    In most working environments it is fairly easy to minimize radiation doses of workers as postulated by radiation protection basics: Increasing the distance to the radiation source, reducing the exposure time, and the use of protective clothing or shielding. With air crews however, being the largest group of exposed persons and receiving the highest collective doses, classical protective measures are difficult or even impossible to enforce. Without neglecting the economical situation, effective measures could nevertheless be realized. Planning flights at slightly lower altitudes and further away from the geomagnetic poles can significantly reduce the radiation exposure for both crew and passengers. Furthermore, affordable high-quality dosimeters with the size of mobile phones have reached marketability. If installed on board, they could measure and display the actually received radiation during normal operation and additionally warn the flight crew in case of an abnormally high dose rate during solar particle events. Pilots could react to such warnings according to procedures that are yet to be installed. (orig.)

  9. Radiation shielding is not a solution. Radiation protection of air crews

    International Nuclear Information System (INIS)

    In most working environments it is fairly easy to minimize radiation doses of workers as postulated by radiation protection basics: Increasing the distance to the radiation source, reducing the exposure time, and the use of protective clothing or shielding. With air crews however, being the largest group of exposed persons and receiving the highest collective doses, classical protective measures are difficult or even impossible to enforce. Without neglecting the economical situation, effective measures could nevertheless be realized. Planning flights at slightly lower altitudes and further away from the geomagnetic poles can significantly reduce the radiation exposure for both crew and passengers. Furthermore, affordable high-quality dosimeters with the size of mobile phones have reached marketability. If installed on board, they could measure and display the actually received radiation during normal operation and additionally warn the flight crew in case of an abnormally high dose rate during solar particle events. Pilots could react to such warnings according to procedures that are yet to be installed. (orig.)

  10. Air Quality – monitoring and modelling

    Directory of Open Access Journals (Sweden)

    Marius DEACONU

    2012-12-01

    Full Text Available Air pollution is a major concern for all nations, regardless of their development. The rapid growth of the industrial sector and urban development have lead to significant quantities of substances and toxic materials, mostly discharged into the atmosphere and having adverse effects both on human health and environment in general. Human society has to recognize that environment has only a limited capacity to process all of its waste without major changes. Each of us is a pollutant but also a victim of pollution. If monitoring of air pollutants is particularly important for assessing the air quality at any moment, by modelling the monitoring data spectacular results are obtained both through the factor analysis and identification of potential pollution mitigation measures. Latest equipment and techniques come and support these problems giving medium and long term solutions.

  11. Assessing Climate Impacts on Air Pollution from Models and Measurements

    Science.gov (United States)

    Holloway, T.; Plachinski, S. D.; Morton, J. L.; Spak, S.

    2011-12-01

    It is well known that large-scale patterns in temperature, humidity, solar radiation and atmospheric circulation affect formation and transport of atmospheric constituents. These relationships have supported a growing body of work projecting changes in ozone (O3), and to a lesser extent aerosols, as a function of changing climate. Typically, global and regional chemical transport models are used to quantify climate impacts on air pollution, but the ability of these models to assess weather-dependent chemical processes has not been thoroughly evaluated. Quantifying model sensitivity to climate poses the additional challenge of isolating the local to synoptic scale effects of meteorological conditions on chemistry and transport from concurrent trends in emissions, hemispheric background concentrations, and land cover change. Understanding how well models capture historic climate-chemistry relationships is essential in projecting future climate impacts, in that it allows for better evaluation of model skill and improved understanding of climate-chemistry relationships. We compare the sensitivity of chemistry-climate relationships, as simulated by the EPA Community Multiscale Air Quality (CMAQ) model, with observed historical response characteristics from EPA Air Quality System (AQS) monitoring data. We present results for O3, sulfate and nitrate aerosols, and ambient mercury concentrations. Despite the fact that CMAQ over-predicts daily maximum 8-hour ground-level O3 concentrations relative to AQS data, the model does an excellent job at simulating the response of O3 to daily maximum temperature. In both model and observations, we find that higher temperatures produce higher O3 across most of the U.S., as expected in summertime conditions. However, distinct regions appear in both datasets where temperature and O3 are anti-correlated - for example, over the Upper Midwestern U.S. states of Iowa, Missouri, Illinois, and Indiana in July 2002. Characterizing uncertainties, errors, and climate sensitivity in CMAQ improves the reliability of future climate and air quality projections.

  12. Compartment models in radiation protection

    International Nuclear Information System (INIS)

    Full text: This paper presents a brief review of the use of compartment models in radiation protection. These models are widely used for modelling the transport of radionuclides in plants, crops, man and animals. Special models are used for the human respiratory tract, gastro-intestinal tract and skeleton, and for particular radionuclides (e.g. transport of strontium, caesium and iodine in sheep and cattle) or groups of radionuclides (e.g. the actinides). Compartment models are also used for assessing the effects of intakes of radionuclides by man in the natural environment, in the workplace, as a result of medical treatment, or as a result of planned or accidental releases of radionuclides to the environment. They are also used for modelling the transport of radionuclides in rivers, estuaries and enclosed seas. Examples of compartment models currently used for some of these applications are presented, and their limitations are discussed. The methods and assumptions used in solving the equations associated with these models are briefly discussed, with particular reference to the problem of assessing the effects of intakes of radionuclides by man

  13. Air pollution model and neural network: an integrated modelling system

    International Nuclear Information System (INIS)

    It is well known that neural networks can work as universal approximators of non-linear functions and they have become a useful tool either where any precise phenomenological model is available or when uncertainty complicates the application of deterministic modelling as, for example, in environmental systems. Usually, N N models are using as regression tool. We have developed an integrated modelling system coupling an air dispersion model with a neural network method both to simulate the influence of important parameters on air pollution models and to minimize the input neural net variables. In our approach, an optimised 3-Layer Perception is used to filter the air pollution concentrations evaluated by means of the non-Gaussian analytical model ADMD. We applied this methodology to the well known Indianapolis urban data set which deals with a release of pollutants from an elevated emission source.

  14. Computer Modeling of Radiation Effects

    OpenAIRE

    Ouchi, N B

    2007-01-01

    Biological effects of low-dose radiation are studied by computational methods. Assessing the risks of low-dose radiation, i.e. radiation-induced cancer, is becoming important in the study of public health because of the many different types of exposures, medical exposures, and from radiation protection viewpoints. In general, radiation effects arise from damage done to DNA by ionizing radiation. Therefore, examining effects from the initial DNA damage to the risk assessment is a problem with ...

  15. Standard climate models radiation codes underestimate black carbon radiative forcing

    Directory of Open Access Journals (Sweden)

    G. Myhre

    2014-10-01

    Full Text Available Radiative forcing (RF of black carbon (BC in the atmosphere is estimated using radiative transfer codes of various complexities. Here we show that the 2-stream radiative transfer codes used most in climate models give too strong forward scattering, leading to enhanced absorption at the surface and too weak absorption by BC. Such calculations are found to underestimate RF by 10% for global mean, all sky conditions, relative to the more sophisticated multi-stream models. The underestimation occurs primarily for low surface albedo, even though BC is more efficient for absorption of solar radiation at high surface albedo.

  16. An air spark glow phase model

    International Nuclear Information System (INIS)

    A )-dimensional kinetic model is developed for the glow phase of a spark gap in air. The model includes heavy-heavy collisions leading to thermal ionization, and electron collision processes. Rates for the latter are calculated by a Boltzmann analysis and from empirical measurements. These include attachment and ionization, excitation/ionization and dissociation/ionization; detachment was found to be necessary to match experimental closing times. With only those processes, the model predicts closing times well over a wide range above and below the DC breakdown voltage

  17. The Cost of Simplifying Air Travel When Modeling Disease Spread

    OpenAIRE

    Lessler, Justin; Kaufman, James H; Ford, Daniel A.; Douglas, Judith V

    2009-01-01

    Background Air travel plays a key role in the spread of many pathogens. Modeling the long distance spread of infectious disease in these cases requires an air travel model. Highly detailed air transportation models can be over determined and computationally problematic. We compared the predictions of a simplified air transport model with those of a model of all routes and assessed the impact of differences on models of infectious disease. Methodology/Principal Findings Using U.S. ticket data ...

  18. Efficiency of hybrid monitoring of air radiation contamination

    International Nuclear Information System (INIS)

    The idea of hybrid monitoring of pollution transport in atmosphere including the united measuring and model monitoring was suggested earlier. An attempt of quantitative estimation of the efficiency of the hybrid monitoring of NPP effluent transport in the atmosphere is made. A method for calculation of errors in estimations of wind velocity and plume axis position for all its points is suggested, and numerical estimates for the hybrid monitoring efficiency are given. The results obtained were used in projects of automated systems for NPP environment radiation monitoring

  19. Air Quality Modelling and the National Emission Database

    DEFF Research Database (Denmark)

    Jensen, S. S.

    The project focuses on development of institutional strengthening to be able to carry out national air emission inventories based on the CORINAIR methodology. The present report describes the link between emission inventories and air quality modelling to ensure that the new national air emission...... inventory is able to take into account the data requirements of air quality models...

  20. 75 FR 4070 - Science Advisory Board Staff Office; Notification of a Public Meeting of the Air Quality Modeling...

    Science.gov (United States)

    2010-01-26

    ... of the Office of Air and Radiation's Second Section 812 Prospective Analysis of the benefits and... are provided to the AQMS: (1) Second Prospective Analysis of Air Quality in the U.S. Air Quality... of Policy Analysis and Review, and (2) Evaluation of CMAQ Model Performance for the 812...

  1. Economic Modeling of Compressed Air Energy Storage

    OpenAIRE

    Rui Bo; Ming Ni; Yang Gu; James McCalley

    2013-01-01

    Due to the variable nature of wind resources, the increasing penetration level of wind power will have a significant impact on the operation and planning of the electric power system. Energy storage systems are considered an effective way to compensate for the variability of wind generation. This paper presents a detailed production cost simulation model to evaluate the economic value of compressed air energy storage (CAES) in systems with large-scale wind power generation. The co-optimizatio...

  2. Meteorological models and the air pollution simulation

    International Nuclear Information System (INIS)

    The atmosphere is the main media to transporting and dispersing the radioactive contaminants in global accidental situations. The possibilities of the air pollution simulation using the meteorological models are studied. This paper presents some possibilities in the VINCA Institute of Nuclear Sciences and Federal Hydrometeorological Institute, Belgrade, for investigations of the environmental impact of chemical and radioactive pollutants released from various power plants and other energy sources. (author)

  3. 40 CFR 1.41 - Office of Air and Radiation.

    Science.gov (United States)

    2010-07-01

    ... of technological developments into improved control program procedures. (c) Office of Radiation... and directs a national surveillance and investigation program for measuring radiation levels in...

  4. Standard climate models radiation codes underestimate black carbon radiative forcing

    OpenAIRE

    Myhre, G.; Samset, B. H.

    2014-01-01

    Radiative forcing (RF) of black carbon (BC) in the atmosphere is estimated using radiative transfer codes of various complexities. Here we show that the 2-stream radiative transfer codes used most in climate models give too strong forward scattering, leading to enhanced absorption at the surface and too weak absorption by BC. Such calculations are found to underestimate RF by 10% for global mean, all sky conditions, relative to the more sophisticated multi-s...

  5. Thermophysics Characterization of Multiply Ionized Air Plasma Absorption of Laser Radiation

    Science.gov (United States)

    Wang, Ten-See; Rhodes, Robert; Turner, Jim (Technical Monitor)

    2002-01-01

    The impact of multiple ionization of air plasma on the inverse Bremsstrahlung absorption of laser radiation is investigated for air breathing laser propulsion. Thermochemical properties of multiply ionized air plasma species are computed for temperatures up to 200,000 deg K, using hydrogenic approximation of the electronic partition function; And those for neutral air molecules are also updated for temperatures up to 50,000 deg K, using available literature data. Three formulas for absorption are calculated and a general formula is recommended for multiple ionization absorption calculation. The plasma composition required for absorption calculation is obtained by increasing the degree of ionization sequentially, up to quadruple ionization, with a series of thermal equilibrium computations. The calculated second ionization absorption coefficient agrees reasonably well with that of available data. The importance of multiple ionization modeling is demonstrated with the finding that area under the quadruple ionization curve of absorption is found to be twice that of single ionization. The effort of this work is beneficial to the computational plasma aerodynamics modeling of laser lightcraft performance.

  6. A new anisotropic diffuse radiation model

    International Nuclear Information System (INIS)

    Highlights: • A new theoretical model of anisotropic diffuse radiation is proposed. • Models are compared with the measured diffuse radiation data. • New model is the best fit with measured values. - Abstract: Through the analysis of distribution of diffuse radiation in the sky, the sky diffuse radiation is divided into four zones. Based on the concept of radiation intensity and solid angle, the corresponding integral equation is established in each zone to build a new theoretical model of anisotropic diffuse radiation. Radiation enhancement coefficients in the new theoretical model are solved from the instantaneous diffuse radiation data received by 30°, 45°, 60° inclined planes, then new model and existing models are compared with the diffuse radiation data received by 90° inclined planes. The results demonstrate that for existing models, Perez model is the most accurate, followed by Liu and Jordan model. Among the second generation models, Klucher model, Hay model, Skartveit and Olseth model are relatively accurate. While compared with existing models, NADR model is more consistent with the measured values. Further comparative analysis shows that for east and north orientations, Perez model and NADR model are more accurate; for south and west orientations, Liu and Jordan model and NADR model are more accurate. Klucher model is well agreed with the measured data in different inclinations. Hay model and Skartveit and Olseth model are relatively accurate on 30° tilt surface, and Temps and Coulson model is also relatively accurate on 45° tilt surface. NADR model is in good agreement with the measured data on 60° and 90° tilt surface. On the whole, NADR model is more accurate than the existing models

  7. OpenAIRE - OpenAIRE sustainability model

    OpenAIRE

    Schmidt, Birgit; Manghi, Paolo; Manola, Natalia; Zoppi, Franco (CNR-ISTI)

    2012-01-01

    This report outlines first steps for the development and implementation of a sustainability plan for OpenAIRE, with the aim to outline how OpenAIRE could be moved from a pilot to a permanent infrastructure. OpenAIRE, a project co-funded by the European Commission's Seventh Framework Program (2009-2012), needs to define a Sustainability Roadmap for its human network of open access experts (National Open Access Desks) and coordinators as well as its technical infrastructure and services. This r...

  8. A simple model for cloud radiative forcing

    OpenAIRE

    Corti, T.; Peter, T

    2009-01-01

    We present a simple model for the longwave and shortwave cloud radiative forcing based on the evaluation of extensive radiative transfer calculations, covering a global range of conditions. The simplicity of the model equations fosters the understanding on how clouds affect the Earth's energy balance. In comparison with results from a comprehensive radiative transfer model, the accuracy of our parameterization is typically better than 20%. We demonstrate the usefulness of our model using...

  9. VALMET-A valley air pollution model

    Energy Technology Data Exchange (ETDEWEB)

    Whiteman, C.D.; Allwine, K.J.

    1983-09-01

    Following a thorough analysis of meteorological data obtained from deep valleys of western Colorado, a modular air-pollution model has been developed to simulate the transport and diffusion of pollutants released from an elevated point source in a well-defined mountain valley during the nighttime and morning transition periods. This initial version of the model, named VALMET, operates on a valley cross section at an arbitrary distance down-valley from a continuous point source. The model has been constructed to include parameterizations of the major physical processes that act to disperse pollution during these time periods. The model has not been fully evaluated. Further testing, evaluations, and development of the model are needed. Priorities for further development and testing are provided.

  10. Phenomenological model of nuclear primary air showers

    Science.gov (United States)

    Tompkins, D. R., Jr.; Saterlie, S. F.

    1976-01-01

    The development of proton primary air showers is described in terms of a model based on a hadron core plus an electromagnetic cascade. The muon component is neglected. The model uses three parameters: a rate at which hadron core energy is converted into electromagnetic cascade energy and a two-parameter sea-level shower-age function. By assuming an interaction length for the primary nucleus, the model is extended to nuclear primaries. Both models are applied over the energy range from 10 to the 13th power to 10 to the 21st power eV. Both models describe the size and age structure (neglecting muons) from a depth of 342 to 2052 g/sq cm.

  11. AIR INGRESS ANALYSIS: COMPUTATIONAL FLUID DYNAMIC MODELS

    International Nuclear Information System (INIS)

    The Idaho National Laboratory (INL), under the auspices of the U.S. Department of Energy, is performing research and development that focuses on key phenomena important during potential scenarios that may occur in very high temperature reactors (VHTRs). Phenomena Identification and Ranking Studies to date have ranked an air ingress event, following on the heels of a VHTR depressurization, as important with regard to core safety. Consequently, the development of advanced air ingress-related models and verification and validation data are a very high priority. Following a loss of coolant and system depressurization incident, air will enter the core of the High Temperature Gas Cooled Reactor through the break, possibly causing oxidation of the in-the core and reflector graphite structure. Simple core and plant models indicate that, under certain circumstances, the oxidation may proceed at an elevated rate with additional heat generated from the oxidation reaction itself. Under postulated conditions of fluid flow and temperature, excessive degradation of the lower plenum graphite can lead to a loss of structural support. Excessive oxidation of core graphite can also lead to the release of fission products into the confinement, which could be detrimental to a reactor safety. Computational fluid dynamic model developed in this study will improve our understanding of this phenomenon. This paper presents two-dimensional and three-dimensional CFD results for the quantitative assessment of the air ingress phenomena. A portion of results of the density-driven stratified flow in the inlet pipe will be compared with results of the experimental results.

  12. AIR INGRESS ANALYSIS: COMPUTATIONAL FLUID DYNAMIC MODELS

    Energy Technology Data Exchange (ETDEWEB)

    Chang H. Oh; Eung S. Kim; Richard Schultz; Hans Gougar; David Petti; Hyung S. Kang

    2010-08-01

    The Idaho National Laboratory (INL), under the auspices of the U.S. Department of Energy, is performing research and development that focuses on key phenomena important during potential scenarios that may occur in very high temperature reactors (VHTRs). Phenomena Identification and Ranking Studies to date have ranked an air ingress event, following on the heels of a VHTR depressurization, as important with regard to core safety. Consequently, the development of advanced air ingress-related models and verification and validation data are a very high priority. Following a loss of coolant and system depressurization incident, air will enter the core of the High Temperature Gas Cooled Reactor through the break, possibly causing oxidation of the in-the core and reflector graphite structure. Simple core and plant models indicate that, under certain circumstances, the oxidation may proceed at an elevated rate with additional heat generated from the oxidation reaction itself. Under postulated conditions of fluid flow and temperature, excessive degradation of the lower plenum graphite can lead to a loss of structural support. Excessive oxidation of core graphite can also lead to the release of fission products into the confinement, which could be detrimental to a reactor safety. Computational fluid dynamic model developed in this study will improve our understanding of this phenomenon. This paper presents two-dimensional and three-dimensional CFD results for the quantitative assessment of the air ingress phenomena. A portion of results of the density-driven stratified flow in the inlet pipe will be compared with results of the experimental results.

  13. Comparative analysis of different approaches to the computation of long-wave radiation balance of water air systems

    International Nuclear Information System (INIS)

    In the present paper, the net long-wave radiation balance of the water-air environmental systems is analysed on the base of several semi-empirical approaches. Various theoretical models of infrared atmospheric radiation are reviewed. Factors, affecting their behavior are considered. Special attention is paid to physical conditions under which those models are applicable. Atmospheric and net infrared radiation fluxes are computed and compared under clear and cloudy sky. Results are presented in graphical form. Conclusions are made on the applicability of models considered for evaluating infrared radiation fluxes in environmental conditions of Central Italy. On the base of present analysis Anderson's model is chosen for future calculations of heat budget of lakes in Central Italy

  14. Influence of future air pollution mitigation strategies on total aerosol radiative forcing

    Directory of Open Access Journals (Sweden)

    S. Kloster

    2008-11-01

    Full Text Available We apply different aerosol and aerosol precursor emission scenarios reflecting possible future control strategies for air pollution in the ECHAM5-HAM model, and simulate the resulting effect on the Earth's radiation budget. We use two opposing future mitigation strategies for the year 2030: one in which emission reduction legislation decided in countries throughout the world are effectively implemented (current legislation; CLE 2030 and one in which all technical options for emission reductions are being implemented independent of their cost (maximum feasible reduction; MFR 2030.

    We consider the direct, semi-direct and indirect radiative effects of aerosols. The total anthropogenic aerosol radiative forcing defined as the difference in the top-of-the-atmosphere radiation between 2000 and pre-industrial times amounts to −2.00 W/m2. In the future this negative global annual mean aerosol radiative forcing will only slightly change (+0.02 W/m2 under the "current legislation" scenario. Regionally, the effects are much larger: e.g. over Eastern Europe radiative forcing would increase by +1.50 W/m2 because of successful aerosol reduction policies, whereas over South Asia it would decrease by −1.10 W/m2 because of further growth of emissions. A "maximum feasible reduction" of aerosols and their precursors would lead to an increase of the global annual mean aerosol radiative forcing by +1.13 W/m2. Hence, in the latter case, the present day negative anthropogenic aerosol forcing could be more than halved by 2030 because of aerosol reduction policies and climate change thereafter will be to a larger extent be controlled by greenhouse gas emissions.

    We combined these two opposing future mitigation strategies for a number of experiments focusing on different sectors and regions. In addition, we performed sensitivity studies to estimate the importance of future changes in oxidant concentrations and the importance of the aerosol microphysical coupling within the range of expected future changes. For changes in oxidant concentrations caused by future air pollution mitigation, we do not find a significant effect for the global annual mean radiative aerosol forcing. In the extreme case of only abating SO2 or carbonaceous emissions to a maximum feasible extent, we find deviations from additivity for the radiative forcing over anthropogenic source regions up to 10% compared to an experiment abating both at the same time.

  15. Determination of the potential radiation exposure of the population close to the Asse II mine caused by deduction of radioactive substances with the discharge air in the normal operation using the ''Atmospheric Radionuclide-Transport-Model'' (ARTM); Ermittlung der potenziellen Strahlenexposition der Bevoelkerung in der Umgebung der Schachtanlage Asse II infolge Ableitung radioaktiver Stoffe mit den abwettern im bestimmungsgemaessen Betrieb mittels des ''atmospaerischen Radionuklid-Transport-Modells'' ARTM

    Energy Technology Data Exchange (ETDEWEB)

    Esch, D.; Wittwer, C. [Bundesamt fuer Strahlenschutz, Salzgitter (Germany)

    2014-01-20

    Between 1967 and 1978 125.787 packages filled with low-level and intermediate-level radioactive waste were emplaced in the mining plant Asse II. Volatile radioactive substances like H-3, C-14 and Rn-222 are released from the emplaced waste. These substances reach the ventilated parts of the mine and are released with the discharge air. The potential radiation exposure of the population caused by deduction of radioactive substances with the discharge air in the normal operation is determined by the ''Atmospheric Radionuclide-Transport-Model'' (ARTM). As result the maximal deductions of volatile radioactive substances with the discharge air in the normal operation of the Asse II mine lead to radiation exposure of the population, which is considerably lower than the permissible values of application rate.

  16. PAT-2 (Plutonium Air Transportable Model 2)

    International Nuclear Information System (INIS)

    The PAT-2 (Plutonium Air Transportable Model 2) package is designed for the safe transport of plutonium and/or uranium in small quantities, especially as used in international safeguards activities, and especially as transported by air. The PAT-2 package is resistant to severe accidents, including that of a high-speed jet aircraft crash, and is designed to withstand such environments as extreme impact, crushing, puncturing and slashing loads, severe hydrocarbon-fueled fires, and deep underwater immersion, with no escape of contents. The accident environments may be imposed upon the package singly or seqentially. The package meets the requirements of 10 CFR 71 for Fissile Class I packages with a cargo of 15 grams of Pu-239, or other isotopic forms described herein, not to exceed 2 watts of thermal activity. Packaging, operational features, and contents of package, are discussed

  17. Determination of shell-radiated noise of an automotive engine air intake system using numerical and experimental techniques

    Science.gov (United States)

    Moenssen, D. J.

    2005-09-01

    Automotive engine air intake noise affects the quality of the total vehicle sound. The degree to which engine air intake noise contributes to the total vehicle sound is controlled by the relative contributions of the airborne, structure-borne, and shell-radiated noise components. Proper tuning of intake noise requires an understanding of how each of these noise sources is generated. In addition, accurate methods for modeling and measuring each noise source are required for efficient development of an acoustically tuned engine air intake system. This paper describes a numerical method that simulates shell-radiated noise due to the coupling between the internal pressure pulsations of an engine air intake system and the structural properties of the intake system. Techniques for tuning the acoustic and structural properties of the numerical models are illustrated. In addition, a hybrid-experimental technique for accurate measurement of shell-radiated noise is proposed. The hybrid measurement technique is also used for further validation of the numerical method. The numerical and experimental techniques are designed to determine the shell noise of vibrating components in the presence of background noise, as is typically the case for engine air intake systems. A duct and sidebranch Helmholtz resonator is used to validate both methods.

  18. Numerical time integration for air pollution models

    OpenAIRE

    Verwer, Jan; Hundsdorfer, Willem; Blom, Joke

    1998-01-01

    Due to the large number of chemical species and the three space dimensions, off-the-shelf stiff ODE integrators are not feasible for the numerical time integration of stiff systems of advection-diffusion-reaction equations [ fracpar{c{t + nabla cdot left( vu{u c right) = nabla cdot left( K ,nabla, c right) + R left( c right), c=c(vu{x,t), c in IR^m, vu{x in Omega subset IR^3 ] from the field of air pollution modelling. This has led to the use of special time integration techniques. This paper...

  19. A mathematical correlation between variations in solar radiation parameters. 2. Global radiation, air temperature and specific humidity

    International Nuclear Information System (INIS)

    We derive from first principles, an equation which expresses global radiation as a function of specific humidity and air temperature at screen height. The practical validity of this equation is tested by using humidity, air temperature and global radiation data from Tanzania. It is shown that global radiation values calculated on the basis of the derived equation agree with measured radiation values to within ± 8% as long as the prevalent (horizontal) winds are either calm or light. It is noted that the equation is equally valid at times of strong horizontal winds provided that the temperature and humidity measuring site is sufficiently shielded from the winds. This implies that meteorological stations that are (for some unavoidable reasons) unable to stock pyranometers can still procure reasonable estimates of local global radiation as long as they can, at least, stock the relatively cheaper barometers and wet- and dry-bulb psychrometers. (author). 12 refs, 1 fig., 4 tabs

  20. Action levels for radon in indoor air and underground work-places. Radiation protection - Leaflet 5

    International Nuclear Information System (INIS)

    Radon in dwellings is the main source of human exposure to ionizing radiation. Recommended action levels are given for radon in indoor air, radon at underground work-places, radon in household water and radioactivity in building materials. 10 refs

  1. Comparison of the effects of gamma radiation on hydrated and air dried rye grass seeds

    International Nuclear Information System (INIS)

    This is a comparative study of the effects of gamma radiation on the growth of hydrated and air dried seeds during the first weeks of primary growth. Four groups of seeds were used in the study: 1) hydrated sweet corn, 2) air dried sweet corn, 3) hydrated rye grass, and 4) air dried rye grass. Each group was then further subdivided and exposed to various levels of gamma radiation using a Cobalt-60 irradiator, except for the control samples of the four groups which received no radiation above background level. All seeds samples were then planted, allowed to grow for approximately 12 days, and harvested. Growth of both shoot and root of each seed was recorded for data analysis according to specific groups. Analyses of data from this study shows that the mean growth of air dried seeds when exposed to gamma radiation prior to planting

  2. A numerical model for multigroup radiation hydrodynamics

    CERN Document Server

    Vaytet, N M H; Dubroca, B; Delahaye, F

    2011-01-01

    We present in this paper a multigroup model for radiation hydrodynamics to account for variations of the gas opacity as a function of frequency. The entropy closure model (M1) is applied to multigroup radiation transfer in a radiation hydrodynamics code. In difference from the previous grey model, we are able to reproduce the crucial effects of frequency-variable gas opacities, a situation omnipresent in physics and astrophysics. We also account for the energy exchange between neighbouring groups which is important in flows with strong velocity divergence. These terms were computed using a finite volume method in the frequency domain. The radiative transfer aspect of the method was first tested separately for global consistency (reversion to grey model) and against a well established kinetic model through Marshak wave tests with frequency dependent opacities. Very good agreement between the multigroup M1 and kinetic models was observed in all tests. The successful coupling of the multigroup radiative transfer...

  3. Advanced air revitalization system modeling and testing

    Science.gov (United States)

    Dall-Baumann, Liese; Jeng, Frank; Christian, Steve; Edeer, Marybeth; Lin, Chin

    1990-01-01

    To support manned lunar and Martian exploration, an extensive evaluation of air revitalization subsystems (ARS) is being conducted. The major operations under study include carbon dioxide removal and reduction; oxygen and nitrogen production, storage, and distribution; humidity and temperature control; and trace contaminant control. A comprehensive analysis program based on a generalized block flow model was developed to facilitate the evaluation of various processes and their interaction. ASPEN PLUS was used in modelling carbon dioxide removal and reduction. Several life support test stands were developed to test new and existing technologies for their potential applicability in space. The goal was to identify processes which use compact, lightweight equipment and maximize the recovery of oxygen and water. The carbon dioxide removal test stands include solid amine/vacuum desorption (SAVD), regenerative silver oxide chemisorption, and electrochemical carbon dioxide concentration (EDC). Membrane-based carbon dioxide removal and humidity control, catalytic reduction of carbon dioxide, and catalytic oxidation of trace contaminants were also investigated.

  4. LIVERMORE REGIONAL AIR QUALITY (LIRAQ) MODEL; TRANSFER TO EPA

    Science.gov (United States)

    Methods were developed to convert data from the Regional Air Pollution/Regional Air Monitoring Study (RAPS/RAMS) into a format compatible with the Livermore Regional Air Quality (LIRAQ) models. Changes made in the LIRAQ models include (1) improved map plotting routines, (2) updat...

  5. Mutiple simultaneous event model for radiation carcinogenesis

    International Nuclear Information System (INIS)

    Theoretical Radiobiology and Risk Estimates includes reports on: Multiple Simultaneous Event Model for Radiation Carcinogenesis; Cancer Risk Estimates and Neutron RBE Based on Human Exposures; A Rationale for Nonlinear Dose Response Functions of Power Greater or Less Than One; and Rationale for One Double Event in Model for Radiation Carcinogenesis

  6. Modeling of diamond radiation detectors

    International Nuclear Information System (INIS)

    We have built up a computer simulation of the detection mechanism in the diamond radiation detectors. The diamond detectors can be fabricated from a chemical vapour deposition polycrystalline diamond film. In this case, the trapping-detrapping and recombination at the defects inside the grains and at the grain boundaries degrade the transport properties of the material and the charge induction processes. These effects may strongly influence the device's response. Previous simulations of this kind of phenomena in the diamond detectors have generally been restricted to the simple detector geometries and homogeneous distribution of the defects. In our model, the diamond film (diamond detector) is simulated by a grid. We apply a spatial and time discretization, regulated by the grid resolution, to the equations describing the charge transport and, by using the Shockley-Ramo theorem, we calculate the signal induced on the electrodes. In this way, we can simulate the effects of the nonhomogeneous distributions of the trapping, recombination, or scattering centers and can investigate the differences observed when different particles, energies, and electrode configurations are used. The simulation shows that the efficiency of the detector increases linearly with the average grain size, that the charge collection distance is small compared to the dimensions of a single grain, and that for small grains, the trapping at the intragrain defects is insignificant compared to the effect of the grain boundaries

  7. Modeling solar radiation at the Earth's surface recent advances

    CERN Document Server

    Badescu, Viorel

    2008-01-01

    Solar radiation data is important for a wide range of applications, e.g. in engineering, agriculture, health sector, and in many fields of the natural sciences. A few examples showing the diversity of applications may include: architecture and building design e.g. air conditioning and cooling systems; solar heating system design and use; solar power generation; weather and climate prediction models; evaporation and irrigation; calculation of water requirements for crops; monitoring plant growth and disease control; skin cancer research. Solar radiation data must be provided in a variety of f

  8. Influence of future air pollution mitigation strategies on total aerosol radiative forcing

    Directory of Open Access Journals (Sweden)

    S. Kloster

    2008-03-01

    Full Text Available We apply different aerosol and aerosol precursor emission scenarios reflecting possible future control strategies for air pollution in the ECHAM5-HAM model, and simulate the resulting effect on the Earth's radiation budget. We use two opposing future mitigation strategies for the year 2030: one in which emission reduction legislation decided in countries throughout the world are effectively implemented (current legislation; CLE 2030 and one in which all technical options for emission reductions are being implemented independent of their cost (maximum feasible reduction; MFR 2030.

    We consider the direct, semi-direct and indirect radiative effects of aerosols. The total anthropogenic aerosol radiative forcing defined as the difference in the top-of-the-atmosphere radiation between 2000 and pre-industrial times amounts to −2.05 W/m2. In the future this negative global annual mean aerosol radiative forcing will only slightly change (+0.02 W/m2 under the "current legislation" scenario. Regionally, the effects are much larger: e.g. over Eastern Europe radiative forcing would increase by +1.50 W/m2 because of successful aerosol reduction policies, whereas over South Asia it would decrease by −1.10 W/m2 because of further growth of emissions. A "maximum feasible reduction" of aerosols and their precursors would lead to an increase of the global annual mean aerosol radiative forcing by +1.13 W/m2. Hence, in the latter case, the present day negative anthropogenic aerosol forcing cloud be more than halved by 2030 because of aerosol reduction policies and climate change thereafter will be to a larger extend be controlled by greenhouse gas emissions.

    We combined these two opposing future mitigation strategies for a number of experiments focusing on different sectors and regions. In addition, we performed sensitivity studies to estimate the importance of future changes in oxidant concentrations and the importance of the aerosol microphysical coupling within the range of expected future changes. For changes in oxidant concentrations in the future within a realistic range, we do not find a significant effect for the global annual mean radiative aerosol forcing. In the extreme case of only abating SO2 or carbonaceous emissions to a maximum feasible extent, we find deviations from additivity for the radiative forcing over anthropogenic source regions up to 10% compared to an experiment abating both at the same time.

  9. OpenAIRE2020 - OpenAIRE data model - D6.1

    OpenAIRE

    Manghi, Paolo; Bardi, Alessia; Atzori, Claudio

    2015-01-01

    The aim of this deliverable is to describe the structure and semantics of the OpenAIRE Information Space, i.e., the OpenAIRE data model, by providing an abstract definition of its main entities and the relationships between them. Requirements have been collected over the years from all "consumers" of the OpenAIRE infrastructure, including data sources (providing content to OpenAIRE), portal end-users of various roles (researchers, project coordinators, general public, research communities), O...

  10. OpenAIRE2020 - OpenAIRE Data Model - D8.1

    OpenAIRE

    Manghi, Paolo; Bardi, Alessia; Atzori, Claudio

    2015-01-01

    The aim of this deliverable is to describe the structure and semantics of the OpenAIRE Information Space, i.e., the OpenAIRE data model, by providing an abstract definition of its main entities and the relationships between them. Requirements have been collected over the years from all "consumers" of the OpenAIRE infrastructure, including data sources (providing content to OpenAIRE), portal end-users of various roles (researchers, project coordinators, general public, research communities), O...

  11. Air quality and radiative forcing impacts of anthropogenic volatile organic compound emissions from ten world regions

    Science.gov (United States)

    Fry, M. M.; Schwarzkopf, M. D.; Adelman, Z.; West, J. J.

    2014-01-01

    Non-methane volatile organic compounds (NMVOCs) influence air quality and global climate change through their effects on secondary air pollutants and climate forcers. Here we simulate the air quality and radiative forcing (RF) impacts of changes in ozone, methane, and sulfate from halving anthropogenic NMVOC emissions globally and from 10 regions individually, using a global chemical transport model and a standalone radiative transfer model. Halving global NMVOC emissions decreases global annual average tropospheric methane and ozone by 36.6 ppbv and 3.3 Tg, respectively, and surface ozone by 0.67 ppbv. All regional reductions slow the production of peroxyacetyl nitrate (PAN), resulting in regional to intercontinental PAN decreases and regional NOx increases. These NOx increases drive tropospheric ozone increases nearby or downwind of source regions in the Southern Hemisphere (South America, Southeast Asia, Africa, and Australia). Some regions' NMVOC emissions contribute importantly to air pollution in other regions, such as East Asia, the Middle East, and Europe, whose impact on US surface ozone is 43%, 34%, and 34% of North America's impact. Global and regional NMVOC reductions produce widespread negative net RFs (cooling) across both hemispheres from tropospheric ozone and methane decreases, and regional warming and cooling from changes in tropospheric ozone and sulfate (via several oxidation pathways). The 100 yr and 20 yr global warming potentials (GWP100, GWP20) are 2.36 and 5.83 for the global reduction, and 0.079 to 6.05 and -1.13 to 18.9 among the 10 regions. The NMVOC RF and GWP estimates are generally lower than previously modeled estimates, due to the greater NMVOC/NOx emissions ratios simulated, which result in less sensitivity to NMVOC emissions changes and smaller global O3 burden responses, in addition to differences in the representation of NMVOCs and oxidation chemistry among models. Accounting for a fuller set of RF contributions may change the relative magnitude of each region's impacts. The large variability in the RF and GWP of NMVOCs among regions suggest that regionally specific metrics may be necessary to include NMVOCs in multi-gas climate trading schemes.

  12. Air quality and radiative forcing impacts of anthropogenic volatile organic compound emissions from ten world regions

    Directory of Open Access Journals (Sweden)

    M. M. Fry

    2013-08-01

    Full Text Available Non-methane volatile organic compounds (NMVOCs influence air quality and global climate change through their effects on secondary air pollutants and climate forcers. Here we simulate the air quality and radiative forcing (RF impacts of changes in ozone, methane, and sulfate from halving anthropogenic NMVOC emissions globally and from 10 regions individually, using a global chemical transport model and a standalone radiative transfer model. Halving global NMVOC emissions decreases global annual average tropospheric methane and ozone by 36.6 ppbv and 3.3 Tg, respectively, and surface ozone by 0.67 ppbv. All regional reductions slow the production of PAN, resulting in regional to intercontinental PAN decreases and regional NOx increases. These NOx increases drive tropospheric ozone increases nearby or downwind of source regions in the Southern Hemisphere (South America, Southeast Asia, Africa, and Australia. Some regions' NMVOC emissions contribute importantly to air pollution in other regions, such as East Asia, Middle East, and Europe, whose impact on US surface ozone is 43%, 34%, and 34% of North America's impact. Global and regional NMVOC reductions produce widespread negative net RFs (cooling across both hemispheres from tropospheric ozone and methane decreases, and regional warming and cooling from changes in tropospheric ozone and sulfate (via several oxidation pathways. The total global net RF for NMVOCs is estimated as 0.0277 W m−2 (~1.8% of CO2 RF since the preindustrial. The 100 yr and 20 yr global warming potentials (GWP100, GWP20 are 2.36 and 5.83 for the global reduction, and 0.079 to 6.05 and −1.13 to 18.9 among the 10 regions. The NMVOC RF and GWP estimates are generally lower than previously modeled estimates, due to differences among models in ozone, methane, and sulfate sensitivities, and the climate forcings included in each estimate. Accounting for a~fuller set of RF contributions may change the relative magnitude of each region's impacts. The large variability in the RF and GWP of NMVOCs among regions suggest that regionally-specific metrics may be necessary to include NMVOCs in multi-gas climate trading schemes.

  13. TH-C-17A-09: Direct Visualization and Monitoring of Medical Radiation Beams in Air

    Energy Technology Data Exchange (ETDEWEB)

    Fahimian, B; Ceballos, A; Turkcan, S; Kapp, D; Pratx, G [Stanford University, Stanford, CA (United States)

    2014-06-15

    Purpose: Radiation therapy errors are rare but potentially catastrophic. Recent fatal incidents could have been avoided by utilizing real-time methods of monitoring delivery of radiation during treatment. However, few existing methods are practical enough to be used routinely. The study presents the first experimental demonstration of a novel non-perturbing method of monitoring radiation therapy through the phenomena of air scintillation. Methods: Monitoring of radiation delivery was devised by leveraging the phenomena of nitrogen excitation in air by ionizing radiation. The excitation induced weak luminescence in the 300–400 nm range, a process called air scintillation. An electron-multiplication charge-coupled device camera (f/0.95 lens; 440 nm shortpass) was set-up in a clinical treatment vault and was used to capture air scintillation images of kilovoltage and megavoltage beams. Monte Carlo simulations were performed to determine the correlation of radiation dose to air scintillation. Results: Megavoltage beams from a Varian Clinac 21EX and kilovoltage beams from an orthovoltage unit (50 kVp, 30 mA) were visualized with a relatively short exposure time (10 s). Cherenkov luminescence produced in a plastic transparent phantom did not interfere with detection of air scintillation. The image intensity displayed an inverse intensity falloff (r{sup 2} = 0.89) along the central axis and was proportional to dose rate (r{sup 2} = 0.9998). As beam energy increased, the divergence of the imaged beam decreased. Last, air scintillation was visualized during a simulated total skin irradiation electron treatment. Conclusion: Air scintillation can be clinically detected to monitor a radiation beam in an inexpensive and non-perturbing manner. This new method is advantageous in monitoring for gross delivery and uniquely capable of wide area in a single acquisition, such as the case for online verification of total body / skin / lymphoid irradiation treatments.

  14. TH-C-17A-09: Direct Visualization and Monitoring of Medical Radiation Beams in Air

    International Nuclear Information System (INIS)

    Purpose: Radiation therapy errors are rare but potentially catastrophic. Recent fatal incidents could have been avoided by utilizing real-time methods of monitoring delivery of radiation during treatment. However, few existing methods are practical enough to be used routinely. The study presents the first experimental demonstration of a novel non-perturbing method of monitoring radiation therapy through the phenomena of air scintillation. Methods: Monitoring of radiation delivery was devised by leveraging the phenomena of nitrogen excitation in air by ionizing radiation. The excitation induced weak luminescence in the 300400 nm range, a process called air scintillation. An electron-multiplication charge-coupled device camera (f/0.95 lens; 440 nm shortpass) was set-up in a clinical treatment vault and was used to capture air scintillation images of kilovoltage and megavoltage beams. Monte Carlo simulations were performed to determine the correlation of radiation dose to air scintillation. Results: Megavoltage beams from a Varian Clinac 21EX and kilovoltage beams from an orthovoltage unit (50 kVp, 30 mA) were visualized with a relatively short exposure time (10 s). Cherenkov luminescence produced in a plastic transparent phantom did not interfere with detection of air scintillation. The image intensity displayed an inverse intensity falloff (r2 = 0.89) along the central axis and was proportional to dose rate (r2 = 0.9998). As beam energy increased, the divergence of the imaged beam decreased. Last, air scintillation was visualized during a simulated total skin irradiation electron treatment. Conclusion: Air scintillation can be clinically detected to monitor a radiation beam in an inexpensive and non-perturbing manner. This new method is advantageous in monitoring for gross delivery and uniquely capable of wide area in a single acquisition, such as the case for online verification of total body / skin / lymphoid irradiation treatments

  15. ACREM: A new air crew radiation exposure measuring system

    International Nuclear Information System (INIS)

    Cosmic radiation has already been discovered in 1912 by the Austrian Nobel Laureate Victor F. Hess. After Hess up to now numerous measurements of the radiation exposure by cosmic rays in different altitudes have been performed, however, this has not been taken serious in view of radiation protection.Today, with the fast development of modern airplanes, an ever increasing number of civil aircraft is flying in increasing altitudes for considerable time. Members of civil aircrew spending up to 1000 hours per year in cruising altitudes and therefore are subject to significant levels of radiation exposure. In 1990 ICRP published its report ICRP 60 with updated excess cancer risk estimates, which led to significantly higher risk coefficients for some radiation qualities. An increase of the radiation weighting factors for mean energy neutron radiation increases the contribution for the neutron component to the equivalent dose by about 60%, as compared to the earlier values of ICRP26. This higher risk coefficients lead to the recommendation of the ICRP, that cosmic radiation exposure in civil aviation should be taken into account as occupational exposure. Numerous recent exposure measurements at civil airliners in Germany, Sweden, USA, and Russia show exposure levels in the range of 3-10 mSv/year. This is significantly more than the average annual dose of radiation workers (in Austria about 1.5 mSv/year). Up to now no practicable and economic radiation monitoring system for routine application on board exits. A fairly simple and economic approach to a practical, active in-flight dosimeter for the assessment of individual crew exposure is discussed in this paper

  16. Enhanced air tasking order optimization model : Kevin R. Crawford.

    OpenAIRE

    Crawford, Kevin R.

    1994-01-01

    This thesis is an enhancement to the Air Tasking Order (ATO) optimization Model, a linear integer optimization model that seeks to match the best air assets against the highest priority targets. The ATO Optimization Model was written as a 1993 Master's Thesis to help the Joint Forces Air Component Commander in wargames rapidly produce an ATO. The model was used in the global wargame SEACON 93 but some difficulties were encountered. Asset utilization was restricted by the static structure of t...

  17. Four-dimensional evaluation of regional air quality models

    OpenAIRE

    Solazzo, E.; Bianconi, R.; Pirovano, G.; M. D. Moran; Vautard, R.; Hogrefe, C.; Matthias, V.; Grossi, P; K. W. Appel; Bessagnet, B; Brandt, J.; C. Chemel; Christensen, J. H.; Forkel, R.; X. V. Francis

    2013-01-01

    The evaluation of regional air quality models is a challenging task, not only for the intrinsic complexity of the topic but also in view of the difficulties in finding sufficiently abundant, harmonized and time/space-well-distributed measurement data. This study, conducted in the framework of AQMEII (Air Quality Model Evaluation International Initiative), evaluates 4-D model predictions obtained from 15 modelling groups and relating to the air quality of the full year of 2006 over the ...

  18. A fitting formula for radiative cooling based on non-local thermodynamic equilibrium population from weakly-ionized air plasma

    International Nuclear Information System (INIS)

    A fitting formula for radiative cooling with collisional-radiative population for air plasma flowfield has been developed. Population number densities are calculated from rate equations in order to evaluate the effects of nonequilibrium atomic and molecular processes. Many elementary processes are integrated to be applied to optically-thin plasmas in the number density range of 1012/cm3 ≤ N ≤ 1019/cm3 and the temperature range of 300 K ≤ T ≤ 40,000 K. Our results of the total radiative emissivity calculated from the collisional-radiative population are fitted in terms of temperature and total number density. To validate the analytic fitting formula, numerical simulation of a laser-induced blast wave propagation with the nonequilibrium radiative cooling is conducted and successfully reproduces the shock and plasma wave front time history observed by experiments. In addition, from the comparison between numerical simulations with the radiation cooling effect based on the fitting formula and those with a gray gas radiation model that assumes local thermodynamic equilibrium, we find that the displacement of the plasma front is slightly different due to the deviation of population probabilities. By using the fitting formula, we can easily and more accurately evaluate the radiative cooling effect without solving detailed collisional-radiative rate equations

  19. Illumination of the Air Environment Using Radiation of HF Broadcast Stations

    Science.gov (United States)

    Lutsenko, V. I.; Lutsenko, I. V.; Popov, I. V.

    2015-06-01

    We consider the possibility of using illumination of the HF broadcast stations for location of air objects. The relationships for estimation of the detection range are obtained and requirements for the degree of suppression of a direct signal from the broadcast station are determined. Spectral characteristics of the signals from HF broadcast stations are studied experimentally for different polarizations of the received radiation. The possibility of air object detection using the Doppler effect is shown. Theoretical estimates of the radar cross section of air objects for different polarizations of the incident radiation are given. It is found experimentally that the radar cross section is about the same for the vertical and horizontal polarizations.

  20. Evaluation of gas radiation models in CFD modeling of oxy-combustion

    International Nuclear Information System (INIS)

    Highlights: • CFD modeling of a typical industrial water tube boiler is conducted. • Different combustion processes were considered including air and oxy-fuel combustion. • SGG, EWBM, Leckner, Perry and WSGG radiation models were considered in the study. • EWBM is the most accurate model and it’s considered to be the benchmark model. • Characteristics of oxy-fuel combustion are compared to those of air–fuel combustion. - Abstract: Proper determination of the radiation energy is very important for proper predictions of the combustion characteristics inside combustion devices using CFD modeling. For this purpose, different gas radiation models were developed and applied in the present work. These radiation models vary in their accuracy and complexity according to the application. In this work, a CFD model for a typical industrial water tube boiler was developed, considering three different combustion environments. The combustion environments are air–fuel combustion (21% O2 and 79% N2), oxy-fuel combustion (21% O2 and 79% CO2) and oxy-fuel combustion (27% O2 and 73% CO2). Simple grey gas (SGG), exponential wide band model (EWBM), Leckner, Perry and weighted sum of grey gases (WSGG) radiation models were examined and their influences on the combustion characteristics were evaluated. Among those radiation models, the EWBM was found to provide close results to the experimental data for the present boiler combustion application. The oxy-fuel combustion characteristics were analyzed and compared with those of air–fuel combustion

  1. Economic Modeling of Compressed Air Energy Storage

    Directory of Open Access Journals (Sweden)

    Rui Bo

    2013-04-01

    Full Text Available Due to the variable nature of wind resources, the increasing penetration level of wind power will have a significant impact on the operation and planning of the electric power system. Energy storage systems are considered an effective way to compensate for the variability of wind generation. This paper presents a detailed production cost simulation model to evaluate the economic value of compressed air energy storage (CAES in systems with large-scale wind power generation. The co-optimization of energy and ancillary services markets is implemented in order to analyze the impacts of CAES, not only on energy supply, but also on system operating reserves. Both hourly and 5-minute simulations are considered to capture the economic performance of CAES in the day-ahead (DA and real-time (RT markets. The generalized network flow formulation is used to model the characteristics of CAES in detail. The proposed model is applied on a modified IEEE 24-bus reliability test system. The numerical example shows that besides the economic benefits gained through energy arbitrage in the DA market, CAES can also generate significant profits by providing reserves, compensating for wind forecast errors and intra-hour fluctuation, and participating in the RT market.

  2. Are passive smoking, air pollution and obesity a greater mortality risk than major radiation incidents?

    Directory of Open Access Journals (Sweden)

    Smith Jim T

    2007-04-01

    Full Text Available Abstract Background Following a nuclear incident, the communication and perception of radiation risk becomes a (perhaps the major public health issue. In response to such incidents it is therefore crucial to communicate radiation health risks in the context of other more common environmental and lifestyle risk factors. This study compares the risk of mortality from past radiation exposures (to people who survived the Hiroshima and Nagasaki atomic bombs and those exposed after the Chernobyl accident with risks arising from air pollution, obesity and passive and active smoking. Methods A comparative assessment of mortality risks from ionising radiation was carried out by estimating radiation risks for realistic exposure scenarios and assessing those risks in comparison with risks from air pollution, obesity and passive and active smoking. Results The mortality risk to populations exposed to radiation from the Chernobyl accident may be no higher than that for other more common risk factors such as air pollution or passive smoking. Radiation exposures experienced by the most exposed group of survivors of Hiroshima and Nagasaki led to an average loss of life expectancy significantly lower than that caused by severe obesity or active smoking. Conclusion Population-averaged risks from exposures following major radiation incidents are clearly significant, but may be no greater than those from other much more common environmental and lifestyle factors. This comparative analysis, whilst highlighting inevitable uncertainties in risk quantification and comparison, helps place the potential consequences of radiation exposures in the context of other public health risks.

  3. Solving vertical transport and chemistry in air pollution models

    International Nuclear Information System (INIS)

    For the time integration of stiff transport-chemistry problems from air pollution modelling, standard ODE solvers are not feasible due to the large number of species and the 3D nature. The popular alternative, standard operator splitting, introduces artificial transients for short-lived species. This complicates the chemistry solution, easily causing large errors for such species. In the framework of an operational global air pollution model, we focus on the problem formed by chemistry and vertical transport, which is based on diffusion, cloud-related vertical winds, and wet deposition. Its specific nature leads to full Jacobian matrices, ruling out standard implicit integration. We compare Strang operator splitting with two alternatives: source splitting and an (unsplit) Rosenbrock method with approximate matrix factorization, all having equal computational cost. The comparison is performed with real data. All methods are applied with half-hour time steps, and give good accuracies. Rosenbrock is the most accurate, and source splitting is more accurate than Strang splitting. Splitting errors concentrate in short-lived species sensitive to solar radiation and species with strong emissions and depositions. 30 refs

  4. Application of Improved Radiation Modeling to General Circulation Models

    Energy Technology Data Exchange (ETDEWEB)

    Michael J Iacono

    2011-04-07

    This research has accomplished its primary objectives of developing accurate and efficient radiation codes, validating them with measurements and higher resolution models, and providing these advancements to the global modeling community to enhance the treatment of cloud and radiative processes in weather and climate prediction models. A critical component of this research has been the development of the longwave and shortwave broadband radiative transfer code for general circulation model (GCM) applications, RRTMG, which is based on the single-column reference code, RRTM, also developed at AER. RRTMG is a rigorously tested radiation model that retains a considerable level of accuracy relative to higher resolution models and measurements despite the performance enhancements that have made it possible to apply this radiation code successfully to global dynamical models. This model includes the radiative effects of all significant atmospheric gases, and it treats the absorption and scattering from liquid and ice clouds and aerosols. RRTMG also includes a statistical technique for representing small-scale cloud variability, such as cloud fraction and the vertical overlap of clouds, which has been shown to improve cloud radiative forcing in global models. This development approach has provided a direct link from observations to the enhanced radiative transfer provided by RRTMG for application to GCMs. Recent comparison of existing climate model radiation codes with high resolution models has documented the improved radiative forcing capability provided by RRTMG, especially at the surface, relative to other GCM radiation models. Due to its high accuracy, its connection to observations, and its computational efficiency, RRTMG has been implemented operationally in many national and international dynamical models to provide validated radiative transfer for improving weather forecasts and enhancing the prediction of global climate change.

  5. Validation of spectral gas radiation models under oxyfuel conditions. Part A: Gas cell experiments

    DEFF Research Database (Denmark)

    Becher, Valentin; Clausen, Snnik; Fateev, Alexander; Spliethoff, Hartmut

    2011-01-01

    AbstractCombustion of hydrocarbon fuels with pure oxygen results in a different flue gas composition as combustion with air. Standard CFD spectral gas radiation models for air combustion are out of their validity range. The series of three articles provides a common spectral basis for the...

  6. Estimation of biomass burning influence on air pollution around Beijing from an aerosol retrieval model.

    Science.gov (United States)

    Mukai, Sonoyo; Yasumoto, Masayoshi; Nakata, Makiko

    2014-01-01

    We investigate heavy haze episodes (with dense concentrations of atmospheric aerosols) occurring around Beijing in June, when serious air pollution was detected by both satellite and ground measurements. Aerosol retrieval is achieved by radiative transfer simulation in an Earth atmosphere model. We solve the radiative transfer problem in the case of haze episodes by successive order of scattering. We conclude that air pollution around Beijing in June is mainly due to increased emissions of anthropogenic aerosols and that carbonaceous aerosols from agriculture biomass burning in Southeast Asia also contribute to pollution. PMID:25250383

  7. Estimation of Biomass Burning Influence on Air Pollution around Beijing from an Aerosol Retrieval Model

    Science.gov (United States)

    Mukai, Sonoyo; Nakata, Makiko

    2014-01-01

    We investigate heavy haze episodes (with dense concentrations of atmospheric aerosols) occurring around Beijing in June, when serious air pollution was detected by both satellite and ground measurements. Aerosol retrieval is achieved by radiative transfer simulation in an Earth atmosphere model. We solve the radiative transfer problem in the case of haze episodes by successive order of scattering. We conclude that air pollution around Beijing in June is mainly due to increased emissions of anthropogenic aerosols and that carbonaceous aerosols from agriculture biomass burning in Southeast Asia also contribute to pollution. PMID:25250383

  8. Evaluating NOx emission inventories for regulatory air quality modeling using satellite and air quality model data

    Science.gov (United States)

    Kemball-Cook, Susan; Yarwood, Greg; Johnson, Jeremiah; Dornblaser, Bright; Estes, Mark

    2015-09-01

    The purpose of this study was to assess the accuracy of NOx emissions in the Texas Commission on Environmental Quality's (TCEQ) State Implementation Plan (SIP) modeling inventories of the southeastern U.S. We used retrieved satellite tropospheric NO2 columns from the Ozone Monitoring Instrument (OMI) together with NO2 columns from the Comprehensive Air Quality Model with Extensions (CAMx) to make top-down NOx emissions estimates using the mass balance method. Two different top-down NOx emissions estimates were developed using the KNMI DOMINO v2.0 and NASA SP2 retrievals of OMI NO2 columns. Differences in the top-down NOx emissions estimates made with these two operational products derived from the same OMI radiance data were sufficiently large that they could not be used to constrain the TCEQ NOx emissions in the southeast. The fact that the two available operational NO2 column retrievals give such different top-down NOx emissions results is important because these retrievals are increasingly being used to diagnose air quality problems and to inform efforts to solve them. These results reflect the fact that NO2 column retrievals are a blend of measurements and modeled data and should be used with caution in analyses that will inform policy development. This study illustrates both benefits and challenges of using satellite NO2 data for air quality management applications. Comparison with OMI NO2 columns pointed the way toward improvements in the CAMx simulation of the upper troposphere, but further refinement of both regional air quality models and the NO2 column retrievals is needed before the mass balance and other emission inversion methods can be used to successfully constrain NOx emission inventories used in U.S. regulatory modeling.

  9. The dynamic radiation environment assimilation model (DREAM)

    International Nuclear Information System (INIS)

    The Dynamic Radiation Environment Assimilation Model (DREAM) is a 3-year effort sponsored by the US Department of Energy to provide global, retrospective, or real-time specification of the natural and potential nuclear radiation environments. The DREAM model uses Kalman filtering techniques that combine the strengths of new physical models of the radiation belts with electron observations from long-term satellite systems such as GPS and geosynchronous systems. DREAM includes a physics model for the production and long-term evolution of artificial radiation belts from high altitude nuclear explosions. DREAM has been validated against satellites in arbitrary orbits and consistently produces more accurate results than existing models. Tools for user-specific applications and graphical displays are in beta testing and a real-time version of DREAM has been in continuous operation since November 2009.

  10. Review on Modelling of the Radiation Belts

    Science.gov (United States)

    Heynderickx, D.

    2002-08-01

    The Earth's trapped radiation belts were discovered at the beginning of the space age and were immediately recognised as a considerable hazard to space missions. Consequently, considerable effort was invested in building models of the trapped proton and electron populations, culminating in the NASA AP-8 and AE-8 models which have been the de facto standards since the seventies. The CRRES mission has demonstrated that the trapped radiation environment is much more complex than the static environment described by the old models. Spatial and especially temporal variations were shown to be much more important than previously thought, and to require more complex models than those in use at that time. Such models are now becoming available, but they are limited in spatial or temporal coverage, and no global, dynamic, trapped radiation belt model is forthcoming. It is therefore vital to co-ordinate future modelling efforts in order to develop new standard models.

  11. Mathematical model of radiation-adsorption purification

    International Nuclear Information System (INIS)

    A mathematical model has been developed for a process for removing harmful substances by radiation and absorption that permits the selection of the optimum treatment parameters: liquid pumping rate, length and cross-sectional area of the adsorption bed, and radiation adsorption dose rate

  12. A numerical model for multigroup radiation hydrodynamics

    International Nuclear Information System (INIS)

    We present in this paper a multigroup model for radiation hydrodynamics to account for variations of the gas opacity as a function of frequency. The entropy closure model (M1) is applied to multigroup radiation transfer in a radiation hydrodynamics code. In difference from the previous grey model, we are able to reproduce the crucial effects of frequency-variable gas opacities, a situation omnipresent in physics and astrophysics. We also account for the energy exchange between neighbouring groups which is important in flows with strong velocity divergence. These terms were computed using a finite volume method in the frequency domain. The radiative transfer aspect of the method was first tested separately for global consistency (reversion to grey model) and against a well-established kinetic model through Marshak wave tests with frequency-dependent opacities. Very good agreement between the multigroup M1 and kinetic models was observed in all tests. The successful coupling of the multigroup radiative transfer to the hydrodynamics was then confirmed through a second series of tests. Finally, the model was linked to a database of opacities for a Xe gas in order to simulate realistic multigroup radiative shocks in Xe. The differences with the previous grey models are discussed.

  13. METEOROLOGICAL MODELLING INFLUENCE ON REGIONAL AND URBAN AIR POLLUTION PREDICTABILITY

    OpenAIRE

    Bande, Stefano; D'Allura, Alessio; Finardi, Sandro; Giorcelli, Matteo; Muraro, Massimo

    2008-01-01

    Abstract: ARPA Piemonte performs yearly air quality assessment running a modelling system based on a chemical transport model. The model is capable to simulate air pollutant emission, transport, diffusion and chemical transformation, to provide concentration fields of the main atmospheric pollutants (CO, NOX, SO2, PM10, PM2.5, O3, and benzene) on a hourly basis and to compute all the indicators required by EU legislation. Meteorological fields to drive air quality simulations are rec...

  14. Radiation protection: Measurement, modelling, documentation. Proceedings

    International Nuclear Information System (INIS)

    The focus of this conference is on the practical aspects of radiation protection and embraces a ''core business'' of radiation protection, namely: measuring, modeling, documentation, and all the activities and good professional practices in this context. The radiation protection experts and the radiation safety officers who contributed papers to this conference are ''practitioners'' in their fields. To round up the subject matter, there are papers dealing with legal aspects, elaborating on recent regulatory provisions and requirements, and papers dicsussing new approaches in designing and disseminating information to the public. (orig./CB)

  15. NCAQ panel examines uses and limitations of air quality models

    International Nuclear Information System (INIS)

    The results of a 22-member expert panel on dispersion modeling, which was convented by the National Commission on Air Quality in 1979, are reviewed. The panel affirmed the validity of using models in support of air quality regulations. It also recognized the need to convey some of the uncertainty in modeling and recommended technical details for the commission to consider

  16. A survey of air flow models for multizone structures

    Energy Technology Data Exchange (ETDEWEB)

    Feustel, H.E.; Dieris, J.

    1991-03-01

    Air flow models are used to simulate the rates of incoming and outgoing air flows for a building with known leakage under given weather and shielding conditions. Additional information about the flow paths and air-mass flows inside the building can only by using multizone air flow models. In order to obtain more information on multizone air flow models, a literature review was performed in 1984. A second literature review and a questionnaire survey performed in 1989, revealed the existence of 50 multizone air flow models, all developed since 1966, two of which are still under development. All these programs use similar flow equations for crack flow but differ in the versatility to describe the full range of flow phenomena and the algorithm provided for solving the set of nonlinear equations. This literature review was found that newer models are able to describe and simulate the ventilation systems and interrelation of mechanical and natural ventilation. 27 refs., 2 figs., 1 tab.

  17. Sensitivity of APSIM/ORYZA model due to estimation errors in solar radiation

    Directory of Open Access Journals (Sweden)

    Alexandre Bryan Heinemann

    2012-01-01

    Full Text Available Crop models are ideally suited to quantify existing climatic risks. However, they require historic climate data as input. While daily temperature and rainfall data are often available, the lack of observed solar radiation (Rs data severely limits site-specific crop modelling. The objective of this study was to estimate Rs based on air temperature solar radiation models and to quantify the propagation of errors in simulated radiation on several APSIM/ORYZA crop model seasonal outputs, yield, biomass, leaf area (LAI and total accumulated solar radiation (SRA during the crop cycle. The accuracy of the 5 models for estimated daily solar radiation was similar, and it was not substantially different among sites. For water limited environments (no irrigation, crop model outputs yield, biomass and LAI was not sensitive for the uncertainties in radiation models studied here.

  18. Decomposition of radiational effects of model feedbacks

    International Nuclear Information System (INIS)

    Three separate doubled CO2 experiments with the statistical dynamic model are used to illustrate efforts to study the climate dynamics, feedbacks, and interrelationships of meteorological parameters by decomposing and isolating their individual effects on radiation transport

  19. Dry deposition modelling of air pollutants over urban areas

    Science.gov (United States)

    Cherin, N.; Roustan, Y.; Seigneur, C.; Musson Genon, L.

    2012-04-01

    More than one-half of the world's inhabitants lives in urban areas. Consequently, the evolution of pollutants inside these urban areas are problems of great concern in air quality studies. Though the dry deposition fluxes of air pollutants, which are known to be significant in the neighborhood of sources of pollution, like urban areas, have not been modeled precisely until recently within urban areas. By reviewing the physics of the processes leading to the dry deposition of air pollutants, it is clear that atmosphere turbulence is crucial for dry deposition. Urban areas, and particularly buildings, are known to significantly impact flow fields and then by extension the dry deposition fluxes. Numerous urban schemes have been developed in the past decades to approximate the effect of the local scale urban elements on drag, heat flux and radiative budget. The most recent urban canopy models are based on quite simple geometries, but sufficiently close to represent the aerodynamic and thermal characteristics of cities. These canopy models are generally intended to parameterize aerodynamic and thermal fields, but not dry deposition. For dry deposition, the current classical "roughness" approach, uses only two representative parameters, z0 and d, namely the roughness length and the zero-plane displacement height to represent urban areas. In this work, an innovative dry deposition model based on the urban canyon concept, is proposed. It considers a single road, bordered by two facing buildings, which are treated separately. It accounts for sub-grid effects of cities, especially a better parameterization of the turbulence scheme, through the use of local mixing length and a more detailled description of the urban area and key parameters within the urban canopy. Three different flow regimes are distinguished in the urban canyon according to the height-to-width ratio: isolated roughness flow, wake interference flow and skimming flow regime. The magnitude of differences in dry deposition fields between both classical "roughness" model and the more complete model developed here is investigated. For instance, the dry deposition fluxes are underestimated by the new model in comparison to the classical one during the day, but are overestimated during the night. This approach also provides spatially segregated dry deposition fields within the urban area which cannot be obtained from the classical "roughness" approach.

  20. Validation of spectral gas radiation models under oxyfuel conditions

    Energy Technology Data Exchange (ETDEWEB)

    Becher, Johann Valentin

    2013-05-15

    Combustion of hydrocarbon fuels with pure oxygen results in a different flue gas composition than combustion with air. Standard computational-fluid-dynamics (CFD) spectral gas radiation models for air combustion are therefore out of their validity range in oxyfuel combustion. This thesis provides a common spectral basis for the validation of new spectral models. A literature review about fundamental gas radiation theory, spectral modeling and experimental methods provides the reader with a basic understanding of the topic. In the first results section, this thesis validates detailed spectral models with high resolution spectral measurements in a gas cell with the aim of recommending one model as the best benchmark model. In the second results section, spectral measurements from a turbulent natural gas flame - as an example for a technical combustion process - are compared to simulated spectra based on measured gas atmospheres. The third results section compares simplified spectral models to the benchmark model recommended in the first results section and gives a ranking of the proposed models based on their accuracy. A concluding section gives recommendations for the selection and further development of simplified spectral radiation models. Gas cell transmissivity spectra in the spectral range of 2.4 - 5.4 {mu}m of water vapor and carbon dioxide in the temperature range from 727 C to 1500 C and at different concentrations were compared in the first results section at a nominal resolution of 32 cm{sup -1} to line-by-line models from different databases, two statistical-narrow-band models and the exponential-wide-band model. The two statistical-narrow-band models EM2C and RADCAL showed good agreement with a maximal band transmissivity deviation of 3 %. The exponential-wide-band model showed a deviation of 6 %. The new line-by-line database HITEMP2010 had the lowest band transmissivity deviation of 2.2% and was therefore recommended as a reference model for the validation of simplified CFD models. In the second results section, spectral measurements (2.4 - 5.4 {mu}m) of a 70 kW turbulent natural gas ame in air blown combustion and in wet and dry oxyfuel combustion were compared with simulated spectra based on measured gas atmospheres. The line-by-line database HITEMP2010 and the two statistical-narrow-band models EM2C and RADCAL were used for the numerical simulation. The measured spectra showed large fluctuations due to turbulence. The averaged experimental intensity was found to be up to 75% higher than the simulated intensity, thus demonstrating the importance of the effect of turbulence-radiation-interaction in combustion simulations. Finally, total emissivities were calculated with the most common spectral models and compared with benchmark calculations by the detailed spectral line-by-line model HITEMP2010. The models were compared at path lengths ranging from 0.001m to 100m and at temperatures from 800 C to 1800 C for atmospheres of pure gases and of various combustion processes (air blown and oxyfuel combustion with wet and dry recirculation) as well as with different fuels (natural gas, brown coal and anthracite). The statistical-narrow-band models RADCAL and EM2C, the exponential-wide-band model and the statistical-line-width model were chosen as models, which are valid for oxyfuel combustion without modifications. A number of weighted-sum-of-grey-gases models from different authors were chosen as computationally efficient models especially developed for oxyfuel combustion. The statistical-narrow-band model EM2C had the highest accuracy with maximum deviations of up to 12%. The weighted-sum-of-grey-gases model from Johansson et al. [64] proved to be the most valid and versatile model for computationally efficient simulations of spectral gas properties with an overall accuracy of 21% or better.

  1. Dispersion modeling of selected PAHs in urban air: A new approach combining dispersion model with GIS and passive air sampling

    Czech Academy of Sciences Publication Activity Database

    Sáňka, O.; Melymuk, L.; Čupr, P.; Dvorská, Alice; Klánová, J.

    2014-01-01

    Roč. 90, oct (2014), s. 88-95. ISSN 1352-2310 Institutional support: RVO:67179843 Keywords : pas sive air sampling * air dispersion modeling * GIS * polycyclic aromatic hydrocarbons * emission inventories Subject RIV: DI - Air Pollution ; Quality Impact factor: 3.281, year: 2014

  2. Radiative flavour violation in SUSY GUT models

    International Nuclear Information System (INIS)

    Present data show clear evidence for new physics beyond minimal flavour violation in the b→ s transition. We discuss radiative sources of flavour violation in the MSSM with boundary conditions from unified theories. We show how a radiatively generated, hierarchical CKM matrix occurs naturally in supersymmetric GUT models and explain the relation between CKM elements and the trilinear SUSY breaking terms Aij. The model makes predictions for FCNC which can be probed at LHCb.

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

    Science.gov (United States)

    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.

  4. Radiation exposure of the crew in commercial air traffic

    International Nuclear Information System (INIS)

    The routine radiation exposure of the crews in Yugoslav Airlines (JAT) has been studied and some previous results are presented. The flights of four selected groups of pilots (four aircraft types) have been studied during one year. Annual exposures and dose equivalents are presented. Some additional results and discussions are given. (1 fig., 4 tabs.)

  5. Handbook of anatomical models for radiation dosimetry

    CERN Document Server

    Eckerman, Keith F

    2010-01-01

    Covering the history of human model development, this title presents the major anatomical and physical models that have been developed for human body radiation protection, diagnostic imaging, and nuclear medicine therapy. It explores how these models have evolved and the role that modern technologies have played in this development.

  6. Assessing solar radiation models using multiple variables over Turkey

    Energy Technology Data Exchange (ETDEWEB)

    Evrendilek, Fatih [Abant Izzet Baysal University, Department of Environmental Engineering, Bolu (Turkey); Ertekin, Can [Akdeniz University, Department of Farm Machinery, Faculty of Agriculture, Antalya (Turkey)

    2008-08-15

    Solar radiation drives many environmental processes; however, needs to be estimated indirectly from more commonly measured meteorological variables since these data are not readily available from most climate stations. A geo-referenced dataset from 159 climate stations of 17 variables (maximum possible sunshine duration, mean, minimum and maximum air temperature, soil temperature, mean and maximum relative humidity, precipitation, cloudiness, evapotranspiration, extraterrestrial radiation, day length, declination angle, day of the year, latitude, longitude, and altitude) was used to model spatio-temporal dynamics of solar radiation over Turkey. A total of 78 empirical models of different mathematical functions with a different combination of 17 explanatory variables were compared based on the error statistics of the Jackknifing validation. The empirical models had adjusted coefficient of determination (R{sub adj} {sup 2}) values of 22.7-96.5% based on the parameterization dataset (P < 0.05). Models 46 and 22.2 provided the most robust performance and were identified as generic models for the estimation of monthly changes in solar radiation over topographically complex terrain of the entire Turkey as a function of maximum possible sunshine hours, extraterrestrial solar radiation, mean temperature, and precipitation. The quadratic and cubic models performed best in terms of the error statistics (P > 0.05), while the performance of the hybrid models was worse than that of the linear, quadratic and cubic models in terms of maximum relative percentage error (e) (P < 0.01). In comparing the interpolation methods of inverse distance weighting and universal co-kriging, anisotropic spherical semi-variogram model of universal co-kriging was found to provide the best description of spatial autocorrelation and variability latent in these data based on the spatial leave-one-out cross-validation. (orig.)

  7. Radiação solar estimada com base na temperatura do ar para três regiões de Minas Gerais Estimation of solar radiation by air temperature models for three regions of Minas Gerais

    Directory of Open Access Journals (Sweden)

    Cláudio R. da Silva

    2012-01-01

    Full Text Available A radiação solar incidente (Rs é uma variável importante em estudos agrícolas, particularmente para a estimativa da evapotranspiração e em modelos para produtividade. Entretanto, sua medição não é, em geral, realizada em estações meteorológicas convencionais. O objetivo deste trabalho foi avaliar nove modelos empíricos de estimativa de Rs, a partir da temperatura, para as regiões Metropolitana, Vale do Rio Doce e Zona da Mata em Minas Gerais. Dados de Rs diários foram obtidos por estações meteorológicas automáticas instaladas nessas regiões e pertencentes ao Instituto Nacional de Meteorologia (INMET. Para todos os modelos foram gerados coeficientes locais de calibração. O desempenho de cada método foi avaliado através dos seguintes indicadores: coeficiente de determinação (R², raiz quadrada do quadrado médio do erro (RQME, erro médio (EM e teste t. A pequena diferença entre os modelos avaliados indica que qualquer um desses modelos é passível de utilização mas, dado à simplicidade, desempenho e significância, o modelo de Hargreaves, calibrado e com dois coeficientes, é o mais aplicável para estimar a radiação solar incidente.The incident solar radiation (Rs is an important variable in agricultural studies, particularly for the estimation of evapotranspiration and yield models. However, its measurement is not commonly performed in conventional meteorological stations. The aim of this study was to evaluate nine empirical models to estimate Rs from the temperature for the Metropolitan, Vale do Rio Doce and Zona da Mata areas in Minas Gerais State, Brazil. The models used were Hargreaves, Annandale, Chen, Bristow & Campbell, Donatelli & Campbell and Hunt. Data used were obtained by Rs daily automatic weather stations installed in these regions and belonging to Instituto Nacional de Meteorologia (INMET. For all models local calibration coefficients were derived. The performance of each method was evaluated using the following statistical indicators: coefficient of determination (R², root mean square error (RMSE, mean bias error (MBE and test-t. The little difference between the models evaluated suggests that any of these models may be used. However, given the simplicity, performance and significance, the model of Hargreaves, calibrated and with two coefficients, is the most suitable for estimating incident solar radiation.

  8. Modelled air pollution levels versus EC air quality legislation - results from high resolution simulation

    OpenAIRE

    Chervenkov, Hristo

    2013-01-01

    An appropriate method for evaluating the air quality of a certain area is to contrast the actual air pollution levels to the critical ones, prescribed in the legislative standards. The application of numerical simulation models for assessing the real air quality status is allowed by the legislation of the European Community (EC). This approach is preferable, especially when the area of interest is relatively big and/or the network of measurement stations is sparse, and the available observati...

  9. Validation of a model for estimating the net radiation over a canopy under reference conditions

    International Nuclear Information System (INIS)

    A study was performed to evaluate a net radiation model in the Panguilemo (UAP) and Corvallis (UAC) agroclimatological plot located in Talca (Chile) and Oregon (USA), respectively. In both location, an automatic meteorological station was installed over a grass canopy maintained in reference conditions to measure net radiation, solar radiation, air temperature and air vapor pressure on hourly basis. Results indicated that there was an excellent correlation between measured (Rno) and estimated (Rne) values of net radiation, with a correlation coefficient of 0,97 and 0,98 for UAP and UAC, respectively. Greater disagreements were observed during the nighttime, but they did not significantly affect the final calculation of net radiation. This analysis suggests that the net radiation model could be used in the Penman-Montieth equation to compute crop water requirement in Talea and Oregon. (author)

  10. Testing and modeling of underfloor air supply plenums

    OpenAIRE

    H. Jin; Bauman, Fred; Webster, T.

    2006-01-01

    The use of an underfloor plenum to deliver conditioned air directly into the occupied zone of a building is one of the key features that distinguish underfloor air distribution systems from conventional ducted overhead systems. This paper describes the development, validation, and application of a computational fluid dynamics (CFD) model for predicting the airflow and thermal performance of underfloor air supply plenums. To provide validation data for comparison with the CFD model, a series o...

  11. Hydrodynamic modeling of semi-planing hulls with air cavities

    Directory of Open Access Journals (Sweden)

    Matveev Konstantin I.

    2015-05-01

    Full Text Available High-speed heavy loaded monohull ships can benefit from application of drag-reducing air cavities under stepped hull bottoms. The subject of this paper is the steady hydrodynamic modeling of semi-planing air-cavity hulls. The current method is based on a linearized potential-flow theory for surface flows. The mathematical model description and parametric calculation results for a selected configuration with pressurized and open air cavities are presented.

  12. Analytical modeling of worldwide medical radiation use

    International Nuclear Information System (INIS)

    An analytical model was developed to estimate the availability and frequency of medical radiation use on a worldwide basis. This model includes medical and dental x-ray, nuclear medicine, and radiation therapy. The development of an analytical model is necessary as the first step in estimating the radiation dose to the world's population from this source. Since there is no data about the frequency of medical radiation use in more than half the countries in the world and only fragmentary data in an additional one-fourth of the world's countries, such a model can be used to predict the uses of medical radiation in these countries. The model indicates that there are approximately 400,000 medical x-ray machines worldwide and that approximately 1.2 billion diagnostic medical x-ray examinations are performed annually. Dental x-ray examinations are estimated at 315 million annually and approximately 22 million in-vivo diagnostic nuclear medicine examinations. Approximately 4 million radiation therapy procedures or courses of treatment are undertaken annually

  13. Ultraviolet-B radiation enhancement in dielectric barrier discharge based xenon chloride exciplex source by air

    International Nuclear Information System (INIS)

    A single barrier dielectric barrier discharge tube of quartz with multi-strip Titanium-Gold (Ti-Au) coatings have been developed and utilized for ultraviolet-B (UV-B) radiation production peaking at wavelength 308 nm. The observed radiation at this wavelength has been examined for the mixtures of the Xenon together with chlorine and air admixtures. The gas mixture composition, chlorine gas content, total gas pressure, and air pressure dependency of the UV intensity, has been analyzed. It is found that the larger concentration of Cl2 deteriorates the performance of the developed source and around 2% Cl2 in this source produced optimum results. Furthermore, an addition of air in the xenon and chlorine working gas environment leads to achieve same intensity of UV-B light but at lower working gas pressure where significant amount of gas is air.

  14. Updating Ontario's air dispersion models : a discussion paper

    International Nuclear Information System (INIS)

    This paper described air dispersion models and technical information relating to Ontario Regulation 346 under the Environmental Protection Act. The Ontario Ministry of the Environment plans to phase out existing air dispersion models and replace them with a series of models from the United States Environmental Protection Agency (in particular AERMOD and ISC-PRIME). However, before adopting the widespread use of the new models in Ontario, the Ministry is undergoing consultation with stakeholders. The Ministry's most recent initiatives in the development of better air quality standards have included the use of the latest scientific information to develop protective, effects-based air standards and the development of a risk management framework to implement the new standards while allowing for time, technology and economic issues to be considered. An update of Regulation 346 air dispersion models ensures that the latest scientific tools are being used to asses compliance with air standards. This will promote the use of the most modern scientific tools available to assess compliance with air quality standards. The major advantage of introducing new air dispersion models is the ability to use effects-based standards with appropriate averaging times to assess compliance. This makes it possible to better assess the health and environmental impacts from air emissions. 3 tabs., 3 figs

  15. Mathematical models for radiation effects on human health

    International Nuclear Information System (INIS)

    In this paper, we are proposing a theoretical approach of basic mathematical models for radiation effect on human health. The largest natural sources of radiation exposure to humans are radon gas. While radon gas has always been in the environment, awareness of its contribution to human radiation exposure has increased in recent years. Radon's primary pathway is through air space in soil and rock. Pressure differences between the soil and the inside of buildings may cause radon gas to move indoors. Radon decays to radon daughters, some of which emit alpha radiation. Alpha-emitting radon daughters are adsorbed on to dust particles which, when inhaled, are trapped in the lungs and may cause gene damage, mutations and finally cancer. Exposure to excess UV radiation increases risk of skin cancer but there is also a dark side. The incidence of all types of skin cancer is related to exposure to UV radiation. Non-melanoma skin cancer, eye melanoma, and lip cancer have also been related to natural UV light

  16. The NIAID Radiation Countermeasures Program business model.

    Science.gov (United States)

    Hafer, Nathaniel; Maidment, Bert W; Hatchett, Richard J

    2010-12-01

    The National Institute of Allergy and Infectious Diseases (NIAID) Radiation/Nuclear Medical Countermeasures Development Program has developed an integrated approach to providing the resources and expertise required for the research, discovery, and development of radiation/nuclear medical countermeasures (MCMs). These resources and services lower the opportunity costs and reduce the barriers to entry for companies interested in working in this area and accelerate translational progress by providing goal-oriented stewardship of promising projects. In many ways, the radiation countermeasures program functions as a "virtual pharmaceutical firm," coordinating the early and mid-stage development of a wide array of radiation/nuclear MCMs. This commentary describes the radiation countermeasures program and discusses a novel business model that has facilitated product development partnerships between the federal government and academic investigators and biopharmaceutical companies. PMID:21142762

  17. Study of the UV radiation bactericidal effect on the bacterial air flora in stock breeding premises

    International Nuclear Information System (INIS)

    The evidence obtained experimentally showed live-stock breeding premises to be constantly exposed to bacterial contamination (the number of microbial bodies may amount to 406000/per m3). The application of bactericide lamps DPT-2500 makes it possible to reduce within 1 min the number of viable microbial cells to 96.6%. Ultraviolet radiation reduces Escherichia coli per cent to 73.9% within 45 sec. These data formed a basis for using ultraviolet air radiation in live-stock breeding premises with heavy bacterial contamination; as a result, the bacterial air content was drastically reduced

  18. A pre design of monitoring for radiation and air contamination in compaction room of RWI

    International Nuclear Information System (INIS)

    The Radioactive Waste Installation (RWI) is a center for processing of radioactive waste coming from various installation applying nuclear science and technology. The RWI has been designed as according to safety standard, so that it will not generate negative impact to the working area and also to the environment. However some measurement should be conducted to know how big of radiation dose and contamination on the air in working area before exposure to the worker. In this case, we will conduct equipments pre design in working area of compaction. Measurement of the contamination uses vacuum pump connected through pipeline using filter while to measure the exposure of radiation uses thermoluminescence dosimeter. The aim of this research is to have pre design the equipments of radiation counter to know exposure of radiation and contamination air in working area compaction to support safety of worker in installation of PTLR. (author)

  19. Modeling Impaired Hippocampal Neurogenesis after Radiation Exposure.

    Science.gov (United States)

    Cacao, Eliedonna; Cucinotta, Francis A

    2016-03-01

    Radiation impairment of neurogenesis in the hippocampal dentate gyrus is one of several factors associated with cognitive detriments after treatment of brain cancers in children and adults with radiation therapy. Mouse models have been used to study radiation-induced changes in neurogenesis, however the models are limited in the number of doses, dose fractions, age and time after exposure conditions that have been studied. The purpose of this study is to develop a novel predictive mathematical model of radiation-induced changes to neurogenesis using a system of nonlinear ordinary differential equations (ODEs) to represent the time, age and dose-dependent changes to several cell populations participating in neurogenesis as reported in mouse experiments exposed to low-LET radiation. We considered four compartments to model hippocampal neurogenesis and, consequently, the effects of radiation treatment in altering neurogenesis: (1) neural stem cells (NSCs), (2) neuronal progenitor cells or neuroblasts (NB), (3) immature neurons (ImN) and (4) glioblasts (GB). Because neurogenesis is decreasing with increasing mouse age, a description of the age-related dynamics of hippocampal neurogenesis is considered in the model, which is shown to be an important factor in comparisons to experimental data. A key feature of the model is the description of negative feedback regulation on early and late neuronal proliferation after radiation exposure. The model is augmented with parametric descriptions of the dose and time after irradiation dependences of activation of microglial cells and a possible shift of NSC proliferation from neurogenesis to gliogenesis reported at higher doses (∼10 Gy). Predictions for dose-fractionation regimes and for different mouse ages, and prospects for future work are then discussed. PMID:26943452

  20. A coupled surface/subsurface flow model accounting for air entrapment and air pressure counterflow

    DEFF Research Database (Denmark)

    Delfs, Jens Olaf; Wang, Wenqing; Kalbacher, Thomas; Singh, Ashok; Kolditz, Olaf

    2013-01-01

    This work introduces the soil air system into integrated hydrology by simulating the flow processes and interactions of surface runoff, soil moisture and air in the shallow subsurface. The numerical model is formulated as a coupled system of partial differential equations for hydrostatic (diffusive...... the mass exchange between compartments. A benchmark test, which is based on a classic experimental data set on infiltration excess (Horton) overland flow, identified a feedback mechanism between surface runoff and soil air pressures. Our study suggests that air compression in soils amplifies surface...

  1. Evaluation of AirGIS: a GIS-based air pollution and human exposure modelling system

    DEFF Research Database (Denmark)

    Ketzel, Matthias; Berkowicz, Ruwim; Hvidberg, Martin; Jensen, Steen Solvang; Raaschou-Nielsen, Ole

    shows, in general, a good performance for both long-term averages (annual and monthly averages), short-term averages (hourly and daily) as well as when reproducing spatial variation in air pollution concentrations. Some shortcomings and future perspectives of the system are discussed too.......This study describes in brief the latest extensions of the Danish Geographic Information System (GIS)-based air pollution and human exposure modelling system (AirGIS), which has been developed in Denmark since 2001 and gives results of an evaluation with measured air pollution data. The system...

  2. Dynamic evaluation of air quality models over European regions

    OpenAIRE

    Thunis, Philippe; PISONI ENRICO; DEGRAEUWE BART; Kranenburg, Richard; Schaap, Martijn; Clappier, Alain

    2014-01-01

    Chemistry-transport models are increasingly used in Europe for estimating air quality or forecasting changes in pollution levels. But with this increased use of modeling arises the need of harmonizing the methodologies to determine the quality of air quality model applications. This is complex for planning applications, i.e. when models are used to assess the impact of realistic or virtual emission scenarios. In this work, the methodology based on the calculation of potencies proposed by Thun...

  3. Dynamic evaluation of air quality models over European regions

    OpenAIRE

    Thunis, P.; Pisoni, E.; Degraeuwe, B.; van Kranenburg, R; Schaap, M.; A. Clappier

    2015-01-01

    Chemistry-transport models are increasingly used in Europe for estimating air quality or forecasting changes in pollution levels. But with this increased use of modeling arises the need of harmonizing the methodologies to determine the quality of air quality model applications. This is complex for planning applications, i.e. when models are used to assess the impact of realistic or virtual emission scenarios. In this work, the methodology based on the calculation of potencies proposed by Thun...

  4. Thermal radiation modelling in a tubular solid oxide fuel cell

    International Nuclear Information System (INIS)

    Solid Oxide Fuel Cells (SOFCs) are becoming the fuel cell of choice among companies and research groups interested in small power generation units. Questions still exist, however, about the operating characteristics of these devices; in particular the temperature distribution in the fuel cell. Using computational fluid dynamics (CFD) a model is proposed that incorporates conduction, convection and radiation. Both surface-to-surface and participating media are considered. It is hoped that a more accurate account of the temperature field in the various flow channels and cell components will be made to assist work on design of fuel cell components and reaction mechanisms. The model, when incorporating radiative heat transfer with participating media, predicts substantially lower operating temperatures and smaller temperature gradients than it does without these equations. It also shows the importance of the cathode air channel in cell cooling. (author)

  5. Dark Radiation Confronting LHC in Z' Models

    CERN Document Server

    Solaguren-Beascoa, A

    2012-01-01

    Recent cosmological data favour additional relativistic degrees of freedom beyond the three active neutrinos and photons, often referred to as "dark radiation". Extensions of the SM involving TeV-scale Z' gauge bosons generically contain superweakly interacting light right-handed neutrinos which can constitute this dark radiation. In this letter we confront the requirement on the parameters of the E6 Z' models to account for the present evidence of dark radiation with the already existing constraints from searches for new neutral gauge bosons at LHC7.

  6. How air influences radiation dose deposition in multiwell culture plates: a Monte Carlo simulation of radiation geometry

    OpenAIRE

    Sabater, Sebastia; Berenguer, Roberto; Honrubia-Gomez, Paloma; Rivera, Miguel; Nuez, Ana; Jimenez-Jimenez, Esther; Martos, Ana; Ramirez-Castillejo, Carmen

    2014-01-01

    Radiation of experimental culture cells on plates with various wells can cause a risk of underdosage as a result of the existence of multiple airwater interfaces. The objective of our study was to quantify this error in culture plates with multiple wells. Radiation conditions were simulated with the GAMOS code, based on the GEANT4 code, and this was compared with a simulation performed with PENELOPE and measured data. We observed a slight underdosage of ?4% on the most superficial half of th...

  7. Cancer risk models for ionizing radiation

    International Nuclear Information System (INIS)

    Risk estimation in radiation carcinogenesis depends primarily on epidemiological data and hazard rate models. The A-bomb survivors follow-up provides information on the complexity of this process. Several hazard rate models are briefly discussed and illustrated using the A-bomb experience

  8. Canonical Ensemble Model for Black Hole Radiation

    Indian Academy of Sciences (India)

    Jingyi Zhang

    2014-09-01

    In this paper, a canonical ensemble model for the black hole quantum tunnelling radiation is introduced. In this model the probability distribution function corresponding to the emission shell is calculated to second order. The formula of pressure and internal energy of the thermal system is modified, and the fundamental equation of thermodynamics is also discussed.

  9. Model of optical nonlinearity of air in the mid-IR wavelength range

    International Nuclear Information System (INIS)

    A model of optical nonlinearity of air (atmospheric nitrogen and oxygen) is developed. This model can be used to calculate numerically the propagation of radiation with a wavelength close to 10 μm. It takes into account the electronic Kerr effect, higher order nonlinearities, ionisation of a gas medium by electron impact, and pulse group-velocity dispersion. The applicability limits of the Drude approximation for calculating the impact-ionisation rate are also considered. (nonlinear optical phenomena)

  10. RRTM: A rapid radiative transfer model

    Energy Technology Data Exchange (ETDEWEB)

    Mlawer, E.J.; Taubman, S.J.; Clough, S.A. [Atmospheric and Environmental Research, Inc., Cambridge, MA (United States)

    1996-04-01

    A rapid radiative transfer model (RRTM) for the calculation of longwave clear-sky fluxes and cooling rates has been developed. The model, which uses the correlated-k method, is both accurate and computationally fast. The foundation for RRTM is the line-by-line radiative transfer model (LBLRTM) from which the relevant k-distributions are obtained. LBLRTM, which has been extensively validated against spectral observations e.g., the high-resolution sounder and the Atmospheric Emitted Radiance Interferometer, is used to validate the flux and cooling rate results from RRTM. Validations of RRTM`s results have been performed for the tropical, midlatitude summer, and midlatitude winter atmospheres, as well as for the four Intercomparison of Radiation Codes in Climate Models (ICRCCM) cases from the Spectral Radiance Experiment (SPECTRE). Details of some of these validations are presented below. RRTM has the identical atmospheric input module as LBLRTM, facilitating intercomparisons with LBLRTM and application of the model at the Atmospheric Radiation Measurement Cloud and Radiation Testbed sites.

  11. Experimental technique of calibration of symmetrical air pollution models

    Indian Academy of Sciences (India)

    P Kumar

    2005-10-01

    Based on the inherent property of symmetry of air pollution models,a Symmetrical Air Pollution Model Index (SAPMI)has been developed to calibrate the accuracy of predictions made by such models,where the initial quantity of release at the source is not known.For exact prediction the value of SAPMI should be equal to 1.If the predicted values are overestimating then SAPMI is > 1and if it is underestimating then SAPMI is < 1.Speci?c design for the layout of receptors has been suggested as a requirement for the calibration experiments.SAPMI is applicable for all variations of symmetrical air pollution dispersion models.

  12. Threshold models in radiation carcinogenesis

    International Nuclear Information System (INIS)

    Cancer incidence and mortality data from the atomic bomb survivors cohort has been analyzed to allow for the possibility of a threshold dose response. The same dose-response models as used in the original papers were fit to the data. The estimated cancer incidence from the fitted models over-predicted the observed cancer incidence in the lowest exposure group. This is consistent with a threshold or nonlinear dose-response at low-doses. Thresholds were added to the dose-response models and the range of possible thresholds is shown for both solid tumor cancers as well as the different leukemia types. This analysis suggests that the A-bomb cancer incidence data agree more with a threshold or nonlinear dose-response model than a purely linear model although the linear model is statistically equivalent. This observation is not found with the mortality data. For both the incidence data and the mortality data the addition of a threshold term significantly improves the fit to the linear or linear-quadratic dose response for both total leukemias and also for the leukemia subtypes of ALL, AML, and CML

  13. Integrated air quality modelling for a designated air quality management area in Glasgow

    Energy Technology Data Exchange (ETDEWEB)

    Mumovic, D. [University College London, London (United Kingdom). The Bartlett School of Graduate Studies; Crowther, J.M. [Glasgow Caledonian University, Glasgow (United Kingdom). School of the Built and Natural Environment; Stevanovic, Z. [Institute of Nuclear Sciences Vinca, University of Belgrade, Belgrade (Yugoslavia)

    2006-12-15

    Currently, most local authorities in the UK use well-established Gaussian-type dispersion models to predict the air quality in urban areas. The use of computational fluid dynamics (CFD) in integrated urban air quality modelling is still in its infancy, despite having an enormous potential in assessing and improving natural ventilation in built-up areas. This study assesses the suitability of a general CFD code (PHOENICS) for use in integrated urban air quality modelling for regulatory purposes. An urban air quality model of a designated air quality management area in the city centre of Glasgow has been developed by integrating traffic flow data for urban road networks, traffic pollutant emission data and a three-dimensional CFD dispersion model of a complex configuration of street canyons. The results are in good agreement with field measurements taken during the continuous monitoring campaign, and show that a general CFD code has indeed the potential for regulatory use. Although this numerical tool has demonstrated satisfactory performance, it is observed that small differences in monitoring station positioning may yield significant variations of the measured mean concentration, due to large values of horizontal and vertical local concentration gradients. Although, at this stage, the accuracy of the developed Glasgow urban air quality model is highly dependent on the experience of its users, it is believed that use of a CFD code (such as PHOENICS) could benefit urban planners, architects, HVAC engineers and all other professionals interested in public health. (author)

  14. A Hybrid Neural Network Prediction Model of Air Ticket Sales

    OpenAIRE

    Han-Chen Huang

    2013-01-01

    Air ticket sales revenue is an important source of revenue for travel agencies, and if future air ticket sales revenue can be accurately forecast, travel agencies will be able to advance procurement to achieve a sufficient amount of cost-effective tickets. Therefore, this study applied the Artificial Neural Network (ANN) and Genetic Algorithms (GA) to establish a prediction model of travel agency air ticket sales revenue. By verifying the empirical data, this study proved that the established...

  15. Eight Year Climatologies from Observational (AIRS) and Model (MERRA) Data

    Science.gov (United States)

    Hearty, Thomas; Savtchenko, Andrey; Won, Young-In; Theobalk, Mike; Vollmer, Bruce; Manning, Evan; Smith, Peter; Ostrenga, Dana; Leptoukh, Greg

    2010-01-01

    We examine climatologies derived from eight years of temperature, water vapor, cloud, and trace gas observations made by the Atmospheric Infrared Sounder (AIRS) instrument flying on the Aqua satellite and compare them to similar climatologies constructed with data from a global assimilation model, the Modern Era Retrospective-Analysis for Research and Applications (MERRA). We use the AIRS climatologies to examine anomalies and trends in the AIRS data record. Since sampling can be an issue for infrared satellites in low earth orbit, we also use the MERRA data to examine the AIRS sampling biases. By sampling the MERRA data at the AIRS space-time locations both with and without the AIRS quality control we estimate the sampling bias of the AIRS climatology and the atmospheric conditions where AIRS has a lower sampling rate. While the AIRS temperature and water vapor sampling biases are small at low latitudes, they can be more than a few degrees in temperature or 10 percent in water vapor at higher latitudes. The largest sampling biases are over desert. The AIRS and MERRA data are available from the Goddard Earth Sciences Data and Information Services Center (GES DISC). The AIRS climatologies we used are available for analysis with the GIOVANNI data exploration tool. (see, http://disc.gsfc.nasa.gov).

  16. Predictive modeling of a radiative shock system

    International Nuclear Information System (INIS)

    A predictive model is constructed for a radiative shock experiment, using a combination of a physics code and experimental measurements. The CRASH code can model the radiation hydrodynamics of the radiative shock launched by the ablation of a Be drive disk and driven down a tube filled with Xe. The code is initialized by a preprocessor that uses data from the Hyades code to model the initial 1.3 ns of the system evolution, with this data fit over seven input parameters by a Gaussian process model. The CRASH code output for shock location from 320 simulations is modeled by another Gaussian process model that combines the simulation data with eight field measurements of a CRASH experiment, and uses this joint model to construct a posterior distribution for the physical parameters of the simulation (model calibration). This model can then be used to explore sensitivity of the system to the input parameters. Comparison of the predicted shock locations in a set of leave-one-out exercises shows that the calibrated model can predict the shock location within experimental uncertainty.

  17. 125I thyroid intakes: consideration of thyroid radiation dose, and air and water concentration limits

    International Nuclear Information System (INIS)

    Two approaches to the calculation of radiation doses to the thyroid are considered. Thyroid burden limits vary depending on whether there is a single intake, or a continuous intake of radioactivity. An important consideration is the use of an equilibrium concentration factor for calculating limits for radio-iodine concentrations in water and air. Tables of suggested limits are presented. (author)

  18. High-efficiency particulate air (HEPA) filter performance following service and radiation exposure

    International Nuclear Information System (INIS)

    Small HEPA filters were exposed to a 60Co source with a radiation strength of 3 x 107 rads per hour and then exposed to steam--air mixtures at several times filter design flow, followed by extended exposure to steam and air at reduced flow. Additional filters were exposed to air flow in a reactor confinement system and then similarly tested with steam--air mixture flows. The test data and calculated effects of filter pluggage with moisture on confinement system performance following potential reactor accidents are described. Gamma radiation exposure impaired the performance of new filters only slightly and temporarily improved performance of service aged filters. Normal confinement system service significantly impaired filter performance although not sufficiently to prevent adequate performance of the SRP confinement system following an unlikely reactor accident. Calculations based on measured filter pluggage indicate that during an accident air flow could be reduced approximately 50 percent with service-degraded HEPA filters present, or approximately 10 percent with new filters damaged by the radiation exposure. (U.S.)

  19. Air pollution modelling on the street canyon

    Czech Academy of Sciences Publication Activity Database

    Bezpalcová, Klára; Jaňour, Zbyněk

    2003-01-01

    Roč. 10, č. 5 (2003), s. 375-386. ISSN 1210-2717 R&D Projects: GA AV ČR KSK3012103; GA MŠk OC 715.10 Institutional research plan: CEZ:AV0Z2076919 Keywords : atmosphere * air pollution * wind tunnel Subject RIV: DG - Athmosphere Sciences, Meteorology

  20. Relativistic model of radiating massive fluid sphere

    Science.gov (United States)

    Pant, Neeraj; Mehta, R. N.; Tewari, B. C.

    2010-06-01

    In this paper we present a new class of nonsingular solutions representing time dependent balls of perfect fluid with matter-radiation in general relativity. The solution of the class is suitable for interior modeling of a quasar i.e. a massive radiating star. The interior solution is matched with a zero pressure Vaidya metric. From this solution we constructed a quasar model by assuming the life time of the quasar of ≈107 year. We obtained a mass of the quasar of ≈109 M θ , linear dimension ≈1017 km and a rate of emission L ∞≈1047 erg/s.

  1. Improvement of local air coolers model in ISAAC

    Energy Technology Data Exchange (ETDEWEB)

    Kim, See Darl; Kim, Dong Ha; Park, Soo Yong; Paik, Chan Young

    2004-02-01

    The purpose of this paper is to assess a new local air coolers model in ISAAC 2.0, as ISAAC 1.0 could model local air coolers only at two locations. In the new model, local air coolers up to twelve locations could be handled. Large LOCA and loss of feed water sequences were selected for the model comparison. Two cases were analyzed with ISAAC 2.0: one with 6 local air coolers in one of the fueling machine room and in the steam generator room, respectively, and the other with 3 local air coolers at both fueling machine room and 6 local air coolers in the steam generator room. The study assumes that the safety systems such as emergency core cooling system, shield cooling system and moderator cooling system are unavailable. According to the ISAAC 2.0 results, the new local air coolers model showed almost no difference between two cases. Also it was found that as the location of LACs increased, the new model worked properly and the effect of LACs was consistent regardless the accident initiators.

  2. FUZZY MODELLING OF LIQUID DESICCANT BASED AIR DEHUMIDIFICATION SYSTEM

    Directory of Open Access Journals (Sweden)

    Harpreet Singh,

    2011-04-01

    Full Text Available This paper describes the Mamdani fuzzy models of heat exchanger and dehumidifier (absorber of an air dehumidification process occurring in a packed bed using liquid desiccant. Temperature of water used ascooling medium at the inlet of heat exchanger, temperature of desiccant solution(from the regenerator ,inlet air humidity ratio of humid air, flow rate per unit cross-sectional area, temperature of desiccant solution(from the heat exchanger have been taken as different variables for packed bed using liquid desiccant .Mamdani Fuzzy model is developed using the above mentioned variables to predict the water condensation rate from the air to the desiccant solution in terms of known operating parameters. The model predictions were compared against a reliable set of experimental data available in the literature and respective mathematical models for their validation. Integrated fuzzy model was also developed forliquid desiccant system

  3. Infrared radiation models for atmospheric methane

    Science.gov (United States)

    Cess, R. D.; Kratz, D. P.; Caldwell, J.; Kim, S. J.

    1986-01-01

    Mutually consistent line-by-line, narrow-band and broad-band infrared radiation models are presented for methane, a potentially important anthropogenic trace gas within the atmosphere. Comparisons of the modeled band absorptances with existing laboratory data produce the best agreement when, within the band models, spurious band intensities are used which are consistent with the respective laboratory data sets, but which are not consistent with current knowledge concerning the intensity of the infrared fundamental band of methane. This emphasizes the need for improved laboratory band absorptance measurements. Since, when applied to atmospheric radiation calculations, the line-by-line model does not require the use of scaling approximations, the mutual consistency of the band models provides a means of appraising the accuracy of scaling procedures. It is shown that Curtis-Godson narrow-band and Chan-Tien broad-band scaling provide accurate means of accounting for atmospheric temperature and pressure variations.

  4. Model of gas-discharge radiation detector

    International Nuclear Information System (INIS)

    The invention is referred to technical physics and can be used for simulation of the work of gas-discharge β-and γ-radiation detector. The model of physical phenomena and devices in which the liquid drop charging is used when it falls on the charged surface is very close to the suggested one. The aim of the invention is to ensure the model adequacy and to provide a posssibility of separate demonstration of the process of β-and γ-radiation detection. It is achieved by the fact that the cathode of a detector model is made in the form of metal, perforated plate with funnel-like holes, it is connected with negative potential of voltage source. The anode is made in the form of metal plate with positive potential of voltage source. The source of drops is fixed above cathode and galvanometer is brought into the circuit. To simulate, the process of γ-radiation detection the source of drops is filled with soapy water, i.e. made in the form of soap bubble source. In the model suggested invisible processes occurring in gas-discharge detector during ionizing radiation detection are adequately modelled by visual transformations with drops and soap bubbles

  5. Rapid measurement of radiation concentration by low-level air-borne spectrometry

    International Nuclear Information System (INIS)

    In order to perform rapid determination of radioactive concentration in air near ground level as well as of the cosmic electromagnetic radiation dose rate in-flight, a portable, battery-powered gamma-ray spectrometer equipped with a NaI(Tl) detecting probe was used. The spectrometer was calibrated using a volumetric source of radioactive rare gas nuclides. The radioactive gas consisting of Ar, Kr, and Xe of known intensity was dispersed in a sealed calibration hangar, and the spectrometer was positioned therein in order to acquire the absolute detection efficiency for the measurement of the concentration of radioactive air-borne contaminants near the ground. To conduct aerial survey, the gamma-ray spectrometer, neutron counter, radiation dosimeter, and the global positioning system were installed onto a transport plane and onto a utility helicopter for contour flight. On-line data are transmitted to the ground experimental station. The transport plane flew several missions and the data revealed the fact that the cosmic neutron and the cosmic electromagnetic radiation level increase as the flight altitude increases from 1,500 ft; the in-flight cosmic radiation is the lowest at the low-level flights below 1,500 ft. The helicopter follows the designated routes in contour flights, 33 feet above ground at a speed of 37 knots, covering a land area of 1.4 million square meters in a one-hour low level aerial survey. The detection limits in such low-level flights are down to 0.1 nSv/h for gamma radiation and 0.5 nSv/h for neutrons. The air-borne survey has proved an efficient, prompt way to rapidly determine the radiation concentration in mid-air as well as near the ground

  6. Simulating aerosol-radiation-cloud feedbacks on meteorology and air quality over eastern China under severe haze conditions in winter

    Science.gov (United States)

    Zhang, Bin; Wang, Yuxuan; Hao, Jiming

    2015-04-01

    The aerosol-radiation-cloud feedbacks on meteorology and air quality over eastern China under severe winter haze conditions during January 2013 are simulated using the fully coupled on-line Weather Research and Forecasting/Chemistry (WRF-Chem) model. Three simulation scenarios including different aerosol configurations are undertaken to distinguish the impact of aerosol radiative (direct and semi-direct) and indirect effects on meteorological variables and air quality. Simulated spatial and temporal variations of PM2.5 are generally consistent with surface observations, with a mean bias of -18.9 μg/m3 (-15.0%) averaged over 71 big cities in China. Comparisons between different scenarios reveal that aerosol radiative effects (direct effect and semi-direct effects) result in reductions of downward shortwave flux at the surface, 2 m temperature, 10 m wind speed and planetary boundary layer (PBL) height by up to 84.0 W/m2, 3.2 oC, 0.8 m/s, and 268 m, respectively. The simulated impact of the aerosol indirect effects is comparatively smaller. Through reducing the PBL height and wind speeds, the aerosol effects lead to increases in surface concentrations of primary pollutants (CO and SO2) and PM2.5. The aerosol feedbacks on secondary pollutants such as surface ozone and PM2.5 mass concentrations show some spatial variations. Surface O3 mixing ratio is reduced by up to 6.9 ppb due to reduced incoming solar radiation and lower temperature. Comparisons of model results with observations show that inclusion of aerosol feedbacks in the model significantly improves model performance in simulating meteorological variables and improves simulations of PM2.5 temporal distributions over the North China Plain, the Yangtze River Delta, the Pearl River Delta, and Central China. Although the aerosol-radiation-cloud feedbacks on aerosol mass concentrations are subject to uncertainties, this work demonstrates the significance of aerosol-radiation-cloud feedbacks for real-time air quality forecasting under haze conditions.

  7. Mixed deterministic statistical modelling of regional ozone air pollution

    KAUST Repository

    Kalenderski, Stoitchko Dimitrov

    2011-03-17

    We develop a physically motivated statistical model for regional ozone air pollution by separating the ground-level pollutant concentration field into three components, namely: transport, local production and large-scale mean trend mostly dominated by emission rates. The model is novel in the field of environmental spatial statistics in that it is a combined deterministic-statistical model, which gives a new perspective to the modelling of air pollution. The model is presented in a Bayesian hierarchical formalism, and explicitly accounts for advection of pollutants, using the advection equation. We apply the model to a specific case of regional ozone pollution-the Lower Fraser valley of British Columbia, Canada. As a predictive tool, we demonstrate that the model vastly outperforms existing, simpler modelling approaches. Our study highlights the importance of simultaneously considering different aspects of an air pollution problem as well as taking into account the physical bases that govern the processes of interest. © 2011 John Wiley & Sons, Ltd..

  8. Air Quality – monitoring and modelling

    OpenAIRE

    Marius DEACONU; Cretu, Mihaiella

    2012-01-01

    Air pollution is a major concern for all nations, regardless of their development. The rapid growth of the industrial sector and urban development have lead to significant quantities of substances and toxic materials, mostly discharged into the atmosphere and having adverse effects both on human health and environment in general. Human society has to recognize that environment has only a limited capacity to process all of its waste without major changes. Each of us is a pollutant but also a v...

  9. A Physically Based Model for Air-Lift Pumping

    Science.gov (United States)

    FrançOis, Odile; Gilmore, Tyler; Pinto, Michael J.; Gorelick, Steven M.

    1996-08-01

    A predictive, physically based model for pumping water from a well using air injection (air-lift pumping) was developed for the range of flow rates that we explored in a series of laboratory experiments. The goal was to determine the air flow rate required to pump a specific flow rate of water in a given well, designed for in-well air stripping of volatile organic compounds from an aquifer. The model was validated against original laboratory data as well as data from the literature. A laboratory air-lift system was constructed that consisted of a 70-foot-long (21-m-long) pipe, 5.5 inches (14 cm) inside diameter, in which an air line of 1.3 inches (3.3 cm) outside diameter was placed with its bottom at different elevations above the base of the long pipe. Experiments were conducted for different levels of submergence, with water-pumping rates ranging from 5 to 70 gallons/min (0.32-4.4 L/s), and air flow ranging from 7 to 38 standard cubic feet/min (0.2-1.1 m3 STP/min). The theoretical approach adopted in the model was based on an analysis of the system as a one-dimensional two-phase flow problem. The expression for the pressure gradient includes inertial energy terms, friction, and gas expansion versus elevation. Data analysis revealed that application of the usual drift-flux model to estimate the air void fraction is not adequate for the observed flow patterns: either slug or churn flow. We propose a modified drift-flux model that accurately predicts air-lift pumping requirements for a range of conditions representative of in-well air-stripping operations.

  10. Olfactory and chemical characterization of indoor air. Towards a psychophysical model for air quality

    Energy Technology Data Exchange (ETDEWEB)

    Berglund, B. (Univ. of Stockholm, Sweden); Berglund, U.; Lindvall, T.; Nicander-Bredberg, H.

    1982-01-01

    The relationship between the odor strength of total air samples and the odor strengths of the constituents was investigated in three field experiments in an office building and a new preschool. The odor strength was scaled by magnitude estimation according to a master scale principle which results in comparable values for the total and the constituent odors. Between 60 and 120 chemical components were detected by GC/FID in the indoor air samples (N = 66). Most (81%) of the detected components in an air sample were odorous, even though most of them were of low concentrations. By a method of pattern analysis, chemical as well as odor patterns of indoor air were found to be characteristic of different buildings. From the odor patterns (POG), the ''odor print'' of the outdoor air associated with the buildings was also recognized in the indoor air. Thus, the ''odor print'' of an air sample is different from its ''chemical print.'' A model was found that predicts the overall odor strength of an air sample from the number of FID-detected components most frequently reported to have a strong odor.

  11. Modeling air quality over China: Results from the Panda project

    Science.gov (United States)

    Katinka Petersen, Anna; Bouarar, Idir; Brasseur, Guy; Granier, Claire; Xie, Ying; Wang, Lili; Wang, Xuemei

    2015-04-01

    China faces strong air pollution problems related to rapid economic development in the past decade and increasing demand for energy. Air quality monitoring stations often report high levels of particle matter and ozone all over the country. Knowing its long-term health impacts, air pollution became then a pressing problem not only in China but also in other Asian countries. The PANDA project is a result of cooperation between scientists from Europe and China who joined their efforts for a better understanding of the processes controlling air pollution in China, improve methods for monitoring air quality and elaborate indicators in support of European and Chinese policies. A modeling system of air pollution is being setup within the PANDA project and include advanced global (MACC, EMEP) and regional (WRF-Chem, EMEP) meteorological and chemical models to analyze and monitor air quality in China. The poster describes the accomplishments obtained within the first year of the project. Model simulations for January and July 2010 are evaluated with satellite measurements (SCIAMACHY NO2 and MOPITT CO) and in-situ data (O3, CO, NOx, PM10 and PM2.5) observed at several surface stations in China. Using the WRF-Chem model, we investigate the sensitivity of the model performance to emissions (MACCity, HTAPv2), horizontal resolution (60km, 20km) and choice of initial and boundary conditions.

  12. A model of interband radiative transition

    Czech Academy of Sciences Publication Activity Database

    Dittrich, Jaroslav; Exner, Pavel; Hirokawa, M.

    2004-01-01

    Roč. 56, č. 3 (2004), s. 753-786. ISSN 0025-5645 R&D Projects: GA AV ČR IAA1048101; GA MŠk ME 482 Institutional research plan: CEZ:AV0Z1048901 Keywords : radiative transition * two-band model Subject RIV: BE - Theoretical Physics Impact factor: 0.366, year: 2004

  13. An integrated air pollution modeling system for urban and regional scales: 1. Structure and performance

    Science.gov (United States)

    Lu, Rong; Turco, Richard P.; Jacobson, Mark Z.

    1997-03-01

    A new three-dimensional air pollution modeling system is described for urban and regional air quality studies. The system includes four major components: a meteorological model, a tracer transport code, a chemical and aerosol microphysical model, and a radiative transfer code. The meteorological model solves the equations of fluid dynamics and thermodynamics over complex terrain and incorporates physical processes such as turbulent diffusion, water vapor condensation and precipitation, solar and infrared radiative transfer, and ground surface processes. The tracer transport code computes the dispersion of gases and aerosols throughout the atmosphere, including the effects of emission sources, and dry and wet deposition. The chemistry/aerosol model treats coupled gas-phase photochemistry and aerosol microphysics and chemistry. Aerosol processes include nucleation, coagulation, condensational growth, evaporation, sedimentation, chemical equilibrium and aqueous chemistry. A detailed radiative transfer code is attached to the dynamical and chemical models. Absorption and scattering by gases and aerosols are explicitly treated to define photodissociation rates, heating and cooling profiles, and boundary layer visibilities. The integrated modeling system, which is referred to as the surface meteorology and ozone generation (SMOG) model, is shown to be a powerful tool for studying coupled dynamical, chemical, and microphysical processes on urban and regional scales.

  14. Estimation of solar radiation for use in crop modelling

    International Nuclear Information System (INIS)

    The aim of this study was to determine the accuracy and applicability of a number of existing and newly developed formulae for calculating solar radiation from other weather variables. Data were taken from eight sites in Ontario, Canada, that had long-term daily weather data sets which included solar radiation. Daily recorded values of minimum and maximum air temperature and precipitation, together with calculated values for clear sky radiation, were used in the formulae. Clear sky radiation was calculated as a function of latitude, day of year, solar angle, and solar constant. Coefficients for five formulae were fitted using data from Elora, Canada. Correlation coefficients between values calculated for individual days and measured data, and errors, were then computed. A newly developed formula that included the maximum temperature, the difference between maximum and minimum temperature, precipitation, and precipitation squared, provided estimates with less error than other formulae. Coefficients for this model and for one other formula were then fitted to data from seven sites. The root mean square error (RMSE) between values calculated for individual days with the newly developed model and measured data for Ontario (Elora) was 4.1 MJ m−2 day−1 with a standard deviation of 0.29 MJ m−2 day−1. When coefficients from one site were used for other sites, the RMSE increased as a linear function of distance between sites; in contrast, when measurements from one site were used for other sites, the RMSE increased curvilinearly with distance. Comparison of errors involved when using coefficients from one site as contrasted to using measured solar radiation indicated that it would be preferable to use measured radiation values if the distance between sites was less than 390 km. Because the RMSE at this separation may not be acceptable for some applications, it was suggested that the curve relating RMSE to separation of sites could be used to establish a 'critical' distance within which measurements should be made. (author)

  15. SAFARI 2000 Modeled Tropospheric Air Mass Trajectories, Dry Season 2000

    Data.gov (United States)

    National Aeronautics and Space Administration — The ETA Forecast Trajectory Model was used to produce forecasts of air-parcel trajectories twice a day at three pressure levels over seven sites in Southern Africa...

  16. SAFARI 2000 Modeled Tropospheric Air Mass Trajectories, Dry Season 2000

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: The ETA Forecast Trajectory Model was used to produce forecasts of air-parcel trajectories twice a day at three pressure levels over seven sites in...

  17. Incorporating principal component analysis into air quality model evaluation

    Science.gov (United States)

    The efficacy of standard air quality model evaluation techniques is becoming compromised as the simulation periods continue to lengthen in response to ever increasing computing capacity. Accordingly, the purpose of this paper is to demonstrate a statistical approach called Princi...

  18. SAFARI 2000 Modeled Tropospheric Air Mass Trajectories, Dry Season 2000

    Data.gov (United States)

    National Aeronautics and Space Administration The ETA Forecast Trajectory Model was used to produce forecasts of air-parcel trajectories twice a day at three pressure levels over seven sites in Southern Africa...

  19. Computer models for optimizing radiation therapy

    International Nuclear Information System (INIS)

    The aim of this contribution is to outline how methods of system analysis, control therapy and modelling can be applied to simulate normal and malignant cell growth and to optimize cancer treatment as for instance radiation therapy. Based on biological observations and cell kinetic data, several types of models have been developed describing the growth of tumor spheroids and the cell renewal of normal tissue. The irradiation model is represented by the so-called linear-quadratic model describing the survival fraction as a function of the dose. Based thereon, numerous simulation runs for different treatment schemes can be performed. Thus, it is possible to study the radiation effect on tumor and normal tissue separately. Finally, this method enables a computer-assisted recommendation for an optimal patient-specific treatment schedule prior to clinical therapy. (orig.)

  20. Evaluation of Observation-Fused Regional Air Quality Model Results for Population Air Pollution Exposure Estimation

    OpenAIRE

    Chen, Gang; Li, Jingyi; Ying, Qi; Sherman, Seth; Perkins, Neil; Rajeshwari, Sundaram; Mendola, Pauline

    2014-01-01

    In this study, Community Multiscale Air Quality (CMAQ) model was applied to predict ambient gaseous and particulate concentrations during 2001 to 2010 in 15 hospital referral regions (HRRs) using a 36-km horizontal resolution domain. An inverse distance weighting based method was applied to produce exposure estimates based on observation-fused regional pollutant concentration fields using the differences between observations and predictions at grid cells where air quality monitors were locate...

  1. Air pollution in Damascus city, radiation, gases, air particulates and heavy elements

    International Nuclear Information System (INIS)

    The purposes of the study were to have a general survey for pollutants in Damascus City, to define the polluted areas and to determine the relationship between the pollutants and its sources, in addition of determining the regretion coefficient for the following elements: K, Ca, Mn, Fe, Cu, Zn, Rb, Sr, Pb and Br. Samples of leaves from different regions of Damascus city were analysed by using x-ray flourescence (XRF) for the mentioned elements. Stat graphics computerized and Surfur programmes were used in order to plot the map of Pb pollutant for Damascus city. Chemical detector tubes produced by Drager Company were used in the absorbtion of air samples for Co, NO2 and ozon where its colours were changed according to the concentration of the interested gases. While, for the measurement of suspended particles, 1400 3m of air samples were taken through fiber gass filter (Wahtman 8x10 in) to measure the concentration of suspended particles. leaves samples were a good indicator for the level of pollution. Results of analysing, a samples by using XRF to determine the concentration of the following elements: Ca, K, Cu, Mn, Fe, Zn, Pb, Rb, Br, and Sr, by using gamma spectroscopy system to difine the isotopes included in it, and to define the activity of 212Pb show that dust and lead are the main pollutants in Damascus city, where the concentration of the suspended particles increased in the crowded transportation areas and reach to more than 700 mg/3m in which it decreases in holidays and at hight, as well as the decrease of the concentration of carbon monoxide at night, which increase in the morning due to the high trafic motion. Rains make a good cleaning factor for the suspended particles in about 80% of it, where the ratio of particles having a diameter less than 10μ to the whole particles range from 30% - 80%. (author)., 25 figs., 35 tabs

  2. Solving vertical transport and chemistry in air pollution models

    OpenAIRE

    Berkvens, Patrick; Botchev, M.A.; Verwer, Jan; M. C. Krol; Peters, W.

    2000-01-01

    For the time integration of stiff transport-chemistry problems from air pollution modelling, standard ODE solvers are not feasible due to the large number of species and the 3D nature. The popular alternative, standard operator splitting, introduces artificial transients for short-lived species. This complicates the chemistry solution, easily causing large errors for such species. In the framework of an operational global air pollution model, we focus on the problem formed by chemistry and ve...

  3. An Analytical Air Pollution Model with Time Dependent Eddy Diffusivity

    OpenAIRE

    Tiziano Tirabassi; Marco Túllio Vilhena; Daniela Buske; Gervásio Annes Degrazia

    2013-01-01

    Air pollution transport and dispersion in the atmospheric boundary layer are modeled by the advection-diffusion equation, that is, essentially, a statement of conservation of the suspended material in an incompressible flow. Many models simulating air pollution dispersion are based upon the solution (numerical or analytical) of the advection-diffusion equation assuming turbulence parameterization for realistic physical scenarios. We present the general time dependent three-dimensional soluti...

  4. Solving vertical transport and chemistry in air pollution models

    OpenAIRE

    Berkvens, P.J.F.; Botchev, M.A.; M. C. Krol; Peters, W.; Verwer, J.G.

    2002-01-01

    For the time integration of stiff transport-chemistry problems from air pollution modelling, standard ODE solvers are not feasible due to the large number of species and the 3D nature. The popular alternative, standard operator splitting, introduces artificial transients for short-lived species. This complicates the chemistry solution, easily causing large errors for such species. In the framework of an operational global air pollution model, we focus on the problem formed by chemistry and ve...

  5. Solving Vertical Transport and Chemistry in Air Pollution Models.

    OpenAIRE

    Berkvens, P.J.F.; Botchev, M.A.; Verwer, J.G.; M. C. Krol; Peters, W.

    2000-01-01

    For the time integration of stiff transport-chemistry problems from air pollution modelling, standard ODE solvers are not feasible due to the large number of species and the 3D nature. The popular alternative, standard operator splitting, introduces artificial transients for short-lived species. This complicates the chemistry solution, easily causing large errors for such species. In the framework of an operational global air pollution model, we focus on the problem formed by chemistry and ve...

  6. VALMET: a valley air pollution model. Final report. Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    Whiteman, C.D.; Allwine, K.J.

    1985-04-01

    An air quality model is described for predicting air pollution concentrations in deep mountain valleys arising from nocturnal down-valley transport and diffusion of an elevated pollutant plume, and the fumigation of the plume on the valley floor and sidewalls after sunrise. Included is a technical description of the model, a discussion of the model's applications, the required model inputs, sample calculations and model outputs, and a full listing of the FORTRAN computer program. 55 refs., 27 figs., 6 tabs.

  7. Technical Note: The air quality modeling system Polyphemus

    Directory of Open Access Journals (Sweden)

    V. Mallet

    2007-05-01

    Full Text Available Polyphemus is an air quality modeling platform which aims at covering the scope and the abilities of modern air quality systems. It deals with applications from local scale to continental scale, using two Gaussian models and two Eulerian models. It manages passive tracers, radioactive decay, photochemistry and aerosol dynamics. The structure of the system includes four independent levels with data management, physical parameterizations, numerical solvers and high-level methods such as data assimilation. This enables sensitivity and uncertainty analysis, primarily through multimodel approaches. On top of the models, drivers implement advanced methods such as model coupling or data assimilation.

  8. Technical Note: The air quality modeling system Polyphemus

    Directory of Open Access Journals (Sweden)

    V. Mallet

    2007-10-01

    Full Text Available Polyphemus is an air quality modeling platform which aims at covering the scope and the abilities of modern air quality systems. It deals with applications from local scale to continental scale, using two Gaussian models and two Eulerian models. It manages passive tracers, radioactive decay, photochemistry and aerosol dynamics. The structure of the system includes four independent levels with data management, physical parameterizations, numerical solvers and high-level methods such as data assimilation. This enables sensitivity and uncertainty analysis, primarily through multimodel approaches. On top of the models, drivers implement advanced methods such as model coupling or data assimilation.

  9. The air shower simulation program CORSIKA and hadronic interaction models

    International Nuclear Information System (INIS)

    CORSIKA is a program for detailed simulation of the evolution of extensive air showers initiated by high-energy cosmic ray particles. Protons, light nuclei up to iron, photons, and many other particles may be treated as primaries. The particles are tracked through the atmosphere until they undergo reactions with the air nuclei or - in the case of instable secondaries - decay. The hadronic interactions at high energies may be described by six reaction models alternatively. The influence of these models on simulation predictions of measurable air shower features is demonstrated with examples. (orig.)

  10. Control of asthma triggers in indoor air with air cleaners: a modeling analysis

    Directory of Open Access Journals (Sweden)

    Allen Joseph G

    2008-08-01

    Full Text Available Abstract Background Reducing exposure to environmental agents indoors shown to increase asthma symptoms or lead to asthma exacerbations is an important component of a strategy to manage asthma for individuals. Numerous investigations have demonstrated that portable air cleaning devices can reduce concentrations of asthma triggers in indoor air; however, their benefits for breathing problems have not always been reproducible. The potential exposure benefits of whole house high efficiency in-duct air cleaners for sensitive subpopulations have yet to be evaluated. Methods We used an indoor air quality modeling system (CONTAM developed by NIST to examine peak and time-integrated concentrations of common asthma triggers present in indoor air over a year as a function of natural ventilation, portable air cleaners, and forced air ventilation equipped with conventional and high efficiency filtration systems. Emission rates for asthma triggers were based on experimental studies published in the scientific literature. Results Forced air systems with high efficiency filtration were found to provide the best control of asthma triggers: 30–55% lower cat allergen levels, 90–99% lower risk of respiratory infection through the inhalation route of exposure, 90–98% lower environmental tobacco smoke (ETS levels, and 50–75% lower fungal spore levels than the other ventilation/filtration systems considered. These results indicate that the use of high efficiency in-duct air cleaners provide an effective means of controlling allergen levels not only in a single room, like a portable air cleaner, but the whole house. Conclusion These findings are useful for evaluating potential benefits of high efficiency in-duct filtration systems for controlling exposure to asthma triggers indoors and for the design of trials of environmental interventions intended to evaluate their utility in practice.

  11. Significance of the air pathway in contributing radiation dose to biota

    International Nuclear Information System (INIS)

    A screening methodology was developed as part of the U.S. Department of Energy's (DOE) graded approach for evaluating radiation doses to aquatic and terrestrial biota from contaminants released into the environment. Included in the graded approach methodology were limiting media concentrations for water, soil, and sediment for twenty-three radionuclides. These concentrations were designed to restrict potential doses to biota below biota dose limits (i.e., dose rate guidelines) specified within existing and proposed DOE regulations. While implicitly included in the derivation of limiting media concentrations, separate biota concentration guides (BCGs) for air were not provided. This paper presents BCGs for air developed within the context and framework of the DOE methodology. The same twenty-three radionuclides are examined. Three air exposure pathways are considered: external exposure (cloudshine), inhalation, and absorption. Allometric equations are used to assess exposure via inhalation, and simplifying assumptions (similar to those used in human dose calculations) are used to assess external and absorption pathways. For purposes of comparison, the air BCGs are compared to current DOE air concentration limits for humans. This analysis validated the initial assumption that the air pathway is unlikely to be a major exposure pathway for biota. In addition, limits for humans are sufficiently restrictive that at sites with active air releases no populations of terrestrial animals or plants are likely to receive significant doses from this exposure pathway. (author)

  12. Artificial intelligence modeling to evaluate field performance of photocatalytic asphalt pavement for ambient air purification.

    Science.gov (United States)

    Asadi, Somayeh; Hassan, Marwa; Nadiri, Ataallah; Dylla, Heather

    2014-01-01

    In recent years, the application of titanium dioxide (TiO₂) as a photocatalyst in asphalt pavement has received considerable attention for purifying ambient air from traffic-emitted pollutants via photocatalytic processes. In order to control the increasing deterioration of ambient air quality, urgent and proper risk assessment tools are deemed necessary. However, in practice, monitoring all process parameters for various operating conditions is difficult due to the complex and non-linear nature of air pollution-based problems. Therefore, the development of models to predict air pollutant concentrations is very useful because it can provide early warnings to the population and also reduce the number of measuring sites. This study used artificial neural network (ANN) and neuro-fuzzy (NF) models to predict NOx concentration in the air as a function of traffic count (Tr) and climatic conditions including humidity (H), temperature (T), solar radiation (S), and wind speed (W) before and after the application of TiO₂ on the pavement surface. These models are useful for modeling because of their ability to be trained using historical data and because of their capability for modeling highly non-linear relationships. To build these models, data were collected from a field study where an aqueous nano TiO₂ solution was sprayed on a 0.2-mile of asphalt pavement in Baton Rouge, LA. Results of this study showed that the NF model provided a better fitting to NOx measurements than the ANN model in the training, validation, and test steps. Results of a parametric study indicated that traffic level, relative humidity, and solar radiation had the most influence on photocatalytic efficiency. PMID:24699867

  13. Utilization of radon progeny in air for education experiment on radiation

    International Nuclear Information System (INIS)

    Radon progeny with short half-lives in the natural air was utilized in the education experiment on radiation that is for the students in the university of Tokyo. Advantage points of the radon progeny are; 1) their short half-lives around 30-50 minutes whose feature is adequate to draw the decay curve in the class and 2) that they exist in the natural air. The most important point of this education experiment is to perform sampling and measuring the radioactivity in the natural area, not in the radiation controlled area. Through the procedure, the students can understand that natural radio-nuclides surely exist around us. Sampling time is 30 minutes at a flow rate of around 60 litters per minute and a glass-fiber filter of GF/F is used, waiting time is one minute and measuring time is sequence of 10 times of 5 minutes (total measuring time; 35 minutes). The total experiment time is around 100 minutes. In the home-tasks, they calculate the radon progeny's concentration in air using the alpha decay curve of the radon progeny on the sampling filter: In addition, they investigate and learn the natural radiation/radioactivity. The radon progeny is useful and effective natural radioactivity for the radiation education. (author)

  14. Air core Bragg fibers for delivery of near-infrared laser radiation

    Science.gov (United States)

    Jelínek, Michal; Frank, Milan; Kubeček, Václav; Matějec, Vlastimil; Kašík, Ivan; Podrazký, Ondřej

    2014-12-01

    Optical fibers designed for high power laser radiation delivery represent important tools in medicine, solar systems, or industry. For such purposes several different types of glass optical fibers such as silica, sapphire, or chalcogenide ones as well as hollow-glass fibers, photonic crystal fibers and Bragg fibers have been investigated. Air-core Bragg fibers or photonic crystal fibers offer us the possibility of light transmission in a low dispersive material - air having a high damage threshold and small non-linear coefficient. However, preforms for drawing Bragg fibers can be fabricated by MCVD method similarly as preforms of standard silica fibers. In this paper we present fundamental characteristics of laboratory-designed and fabricated Bragg fibers with air cores intended for delivery of laser radiation at a wavelength range from 0.9 to 1.5 μm. Bragg fibers with different air core diameters of 5, 45 and 73 mm were prepared. The fiber core was surrounded by three pairs of circular Bragg layers. Each pair was composed of one layer with a high and one layer with a low refractive index with a contrast up to 0.03. Several laser sources emitting at 0.975, 1.06, and 1.55 μm were used as radiation sources. Attenuation coefficients, overall transmissions, bending losses, and spatial profiles of output beams from fibers were determined at these wavelengths. The lowest attenuation coefficient of 70 dB/km was determined for the 45 μm and 73 mm air-core fiber when radiation from a laser was launched into the fibers by using optical lenses. However, multimodal transmission has been observed in such condition. It has also been found that bending losses of such fibers are negligible for bending diameters higher than 15 mm.

  15. Dark radiation confronting LHC in Z′ models

    International Nuclear Information System (INIS)

    Recent cosmological data favour additional relativistic degrees of freedom beyond the three active neutrinos and photons, often referred to as “dark radiation”. Extensions of the SM involving TeV-scale Z′ gauge bosons generically contain superweakly interacting light right-handed neutrinos which can constitute this dark radiation. In this Letter we confront the requirement on the parameters of the E6Z′ models to account for the present evidence of dark radiation with the already existing constraints from searches for new neutral gauge bosons at LHC7

  16. Response of tomato to radiation intensity and air temperature under plastic-house ultraviolet protection

    International Nuclear Information System (INIS)

    Enhance of ultraviolet radiation intensity on the earth surface affected by ozon depletion on stratospheric layer cause changing on the response of plant to radiation quality. One technique for reducing photo destructive UV radiation is micro climate modification by using mulch and plastic-cover UV protection. So that, growth and yield of plant can be optimalized. This research designed an experiment to find out the effect of two kinds of plastic-cover, UV plastic and conventional plastic, on microclimate condition and tomato performance under plastic-house. The result of this research described that mulch and plastic cover can modify radiation and air temperature under plastics-house, but it can not improve growth and yield of the tomato

  17. The cosmic radiation environment at air carrier flight altitudes and possible associated health risks

    International Nuclear Information System (INIS)

    The cosmic radiation environment at air carrier flight altitudes is described and estimates are given of the amount of galactic cosmic radiation received on a wide variety of routes to and from, and within the United States. Methods are provided to assess health risks incurred by aircrews from occupational exposure to galactic radiation. On the 32 flights studied, the highest dose of galactic radiation received by a crew member who worked as many as 1000 block hours a year would be less than half the average annual limit of 20 mSv recommended by the International Commission on Radiological Protection for a non-pregnant occupationally exposed adult. A pregnant crew member who worked 70 block hours a month for 5 months would exceed the recommended 2mSv pregnancy limit on about one-third of the flights. (author)

  18. Radiation impact caused by activation of air from the future GSI accelerator facility fair

    International Nuclear Information System (INIS)

    The Gesellschaft fuer Schwerionenforschung in Darmstadt is planning a new accelerator Facility for Antiproton and Ion Research (FAIR). Two future experimental areas are regarded to be the most decisive points concerning the activation of air. One is the area for the production of antiprotons. A second crucial experimental area is the so-called Super Fragment Separator. The production of radioactive isotopes in air is calculated using the residual nuclei option of the Monte Carlo program FLUKA. The results are compared with the data for the activation of air given by Sullivan and in IAEA report 283. The resulting effective dose is calculated using a program package from the German Federal Office for Radiation Protection, the Bundesamt fuer Stranlenschutz. The results demonstrate that a direct emission of the total radioactivity produced into the air will probably conflict with the limits of the German Radiation Protection Ordinance. Special measures have to be planned in order to reduce the amount of radioactivity released into the air. (authors)

  19. APPLICATIONS OF DECISION THEORY TECHNIQUES IN AIR POLLUTION MODELING

    Science.gov (United States)

    The study applies methods of operations research to two basic areas of air pollution modeling: (1) the generation of wind fields for use in models of regional scale transport, diffusion and chemistry; and (2) the application of models in studies of optimal pollution control strat...

  20. Gas radiation effects on opposing double-diffusive convection in a non-gray air-H2O mixture

    International Nuclear Information System (INIS)

    We studied numerically the effects of gas radiation on double-diffusive convection in a square enclosure filled with a non-gray air-H2O mixture at different concentrations. Uniform temperatures and concentrations are imposed along the two vertical side walls of the enclosure so as to induce opposing thermal and mass buoyancy forces within the fluid. In this work, the radiative aspect of the problem is treated by the discrete ordinate method (to solve the radiative transfer equation) and the SLW spectral model (to account for the radiative properties of the non-gray mixture). Gas absorption varies with the local concentration of H2O, which induces a strong direct coupling between the concentration and thermal fields that otherwise would not exist. Numerical results show that radiative effects on the characteristics of streamline, temperature and concentration fields are important, and depend on the nature of the flow regime (thermal at 5% H2O, transitional at 10% and mass at 25%). The total heat transfer is reduced whatever the flow regime and the mass transfer is also affected, outside the thermal flow. (authors)

  1. Spatial distribution of emissions to air – the SPREAD model

    DEFF Research Database (Denmark)

    Plejdrup, Marlene Schmidt; Gyldenkærne, Steen

    requirements for reporting of gridded emissions to CLRTAP. Spatial emission data is e.g. used as input for air quality modelling, which again serves as input for assessment and evaluation of health effects. For these purposes distributions with higher spatial resolution have been requested. Previously, a......The National Environmental Research Institute (NERI), Aarhus University, completes the annual national emission inventories for greenhouse gases and air pollutants according to Denmark’s obligations under international conventions, e.g. the climate convention, UNFCCC and the convention on long......-range transboundary air pollution, CLRTAP. NERI has developed a model to distribute emissions from the national emission inventories on a 1x1 km grid covering the Danish land and sea territory. The new spatial high resolution distribution model for emissions to air (SPREAD) has been developed according to the...

  2. A modeling perspective on cloud radiative forcing

    International Nuclear Information System (INIS)

    Radiation fields from a perpetual July integration of a T106 version of the ECM-WF operational model are used to identify the most appropriate way to diagnose cloud radiative forcing in a general circulation model, for the purposes of intercomparison between models. Differences between the Methods I and II of Cess and Potter (1987) and a variant method are addressed. Method I is shown to be the least robust of all methods, due to the potential uncertainties related to persistent cloudiness, length of the sampling period and biases in retrieved clear-sky quantities due to insufficient sampling of the diurnal cycle. Method II is proposed as an unambiguous way to produce consistent radiative diagnostics for intercomparing model results. The impact of the three methods on the derived sensitivities and cloud feedbacks following an imposed change in sea surface temperature is discussed. The sensitivity of the results to horizontal resolution is considered by using the diagnostics from parallel integrations with T21 version of the model

  3. Modelling heat and mass transfer in a membrane-based air-to-air enthalpy exchanger

    Science.gov (United States)

    Dugaria, S.; Moro, L.; Del, D., Col

    2015-11-01

    The diffusion of total energy recovery systems could lead to a significant reduction in the energy demand for building air-conditioning. With these devices, sensible heat and humidity can be recovered in winter from the exhaust airstream, while, in summer, the incoming air stream can be cooled and dehumidified by transferring the excess heat and moisture to the exhaust air stream. Membrane based enthalpy exchangers are composed by different channels separated by semi-permeable membranes. The membrane allows moisture transfer under vapour pressure difference, or water concentration difference, between the two sides and, at the same time, it is ideally impermeable to air and other contaminants present in exhaust air. Heat transfer between the airstreams occurs through the membrane due to the temperature gradient. The aim of this work is to develop a detailed model of the coupled heat and mass transfer mechanisms through the membrane between the two airstreams. After a review of the most relevant models published in the scientific literature, the governing equations are presented and some simplifying assumptions are analysed and discussed. As a result, a steady-state, two-dimensional finite difference numerical model is setup. The developed model is able to predict temperature and humidity evolution inside the channels. Sensible and latent heat transfer rate, as well as moisture transfer rate, are determined. A sensitive analysis is conducted in order to determine the more influential parameters on the thermal and vapour transfer.

  4. Improving the marketing abilities of some egyptian exports using radiation technology in cairo air port

    International Nuclear Information System (INIS)

    The economics of establishing a food irradiation facility at cairo airport are discussed together with the effect of various parameters on uint processing costs. This study comprises the determination of the commodity mix for the egyptian food commodities that are proposed for irradiation and export from the cairo airport. The commodity mix is distributed for the full utilization of the working capacity and the evaluation of the type of the irradiation facility and also the radiation source strength. The financial analysis for such an irradiation facility is also carried out. It provides a model for calculating specific unit processing costs by correlating known capital costs with annual operation cost and annual throughputs. We analyzed the cost- benefit of the proposed food irradiation facility. We took into account the cost of the capital investment, operation and other additional parameters and then estimated the unit cost. The investment criteria utilized for commercial evaluation were internal rate of return (I.I.R.) and pay back period (P.B.P.). The irradiation cost and the additional income are also discussed. The results of this analysis showed that the installation of the an irradiation unit for the establishment of food irradiation unit in cairo air port in would be economically feasible

  5. Sigmoidal response model for radiation risk

    International Nuclear Information System (INIS)

    From epidemiologic studies, we find no measurable increase in the incidences of birth defects and cancer after low-level exposure to radiation. Based on modern understanding of the molecular basis of teratogenesis and cancer, I attempt to explain thresholds observed in atomic bomb survivors, radium painters, uranium workers and patients injected with Thorotrast. Teratogenic injury induced by doses below threshold will be completely eliminated as a result of altruistic death (apoptosis) of injured cells. Various lines of evidence obtained show that oncomutations produced in cancerous cells after exposure to radiation are of spontaneous origin and that ionizing radiation acts not as an oncomutation inducer but as a tumor promoter by induction of chronic wound-healing activity. The tissue damage induced by radiation has to be repaired by cell growth and this creates opportunity for clonal expansion of a spontaneously occurring preneoplastic cell. If the wound-healing error model is correct, there must be a threshold dose range of radiation giving no increase in cancer risk. (author)

  6. Mathematical Modeling of Food Freezing in Air-Blast Freezer

    OpenAIRE

    Guiqiang Wang; Pinghua Zou

    2014-01-01

    A mathematical model for simulating the heat transfer during food freezing was presented. The model consists of three steps. First, the flow field inside the freezing chamber was modeled using the CFD method, based on which the freezing condition, including the temperature and velocity around the food, was calculated. Second, the heat transfer coefficient between food and air was calculated in the CFD model. Third, a finite-difference model was employed to simulate the heat transfer inside th...

  7. Air Leakage of U.S. Homes: Model Prediction

    Energy Technology Data Exchange (ETDEWEB)

    Sherman, Max H.; McWilliams, Jennifer A.

    2007-01-01

    Air tightness is an important property of building envelopes. It is a key factor in determining infiltration and related wall-performance properties such as indoor air quality, maintainability and moisture balance. Air leakage in U.S. houses consumes roughly 1/3 of the HVAC energy but provides most of the ventilation used to control IAQ. The Lawrence Berkeley National Laboratory has been gathering residential air leakage data from many sources and now has a database of more than 100,000 raw measurements. This paper uses a model developed from that database in conjunction with US Census Bureau data for estimating air leakage as a function of location throughout the US.

  8. Clouds in a one dimensional radiation model

    Energy Technology Data Exchange (ETDEWEB)

    Wyser, K.

    1996-05-01

    The importance of clouds for the radiation budget of the earth is well known but less understood. This study compares several broadband parameterizations for the radiative properties of clouds from the works of different authors. Water and ice clouds are treated separately. All parameterizations are based on the effective radius (r{sub e}) as a measure for the microphysical composition of the clouds. The clouds are embedded in a one dimensional radiation scheme of the type suitable for GCMs and NWP models. A water cloud from JASIN and two ice clouds from ICE`89 are chosen as test cases. The radiative fluxes, both SW and LW, from any of the tested parameterizations are close to the observations. The LW fluxes in ice clouds are the only situations where ECHAM is clearly closer to the observations than ECMWF. The SW cloud absorption from this study is slightly higher for both water and ice clouds compared to other models or observations. Only qualitative statements are possible concerning the LW cloud absorption because additional, non-observed but probably present clouds below or above the test clouds may easily affect the absorption. 29 refs, 8 refs, 10 tabs

  9. How air influences radiation dose deposition in multiwell culture plates: a Monte Carlo simulation of radiation geometry

    Science.gov (United States)

    Sabater, Sebastia; Berenguer, Roberto; Honrubia-Gomez, Paloma; Rivera, Miguel; Nuez, Ana; Jimenez-Jimenez, Esther; Martos, Ana; Ramirez-Castillejo, Carmen

    2014-01-01

    Radiation of experimental culture cells on plates with various wells can cause a risk of underdosage as a result of the existence of multiple airwater interfaces. The objective of our study was to quantify this error in culture plates with multiple wells. Radiation conditions were simulated with the GAMOS code, based on the GEANT4 code, and this was compared with a simulation performed with PENELOPE and measured data. We observed a slight underdosage of ?4% on the most superficial half of the culture medium. We believe that this underdosage does not have a significant effect on the dose received by culture cells deposited in a monolayer and adhered to the base of the wells. PMID:24722683

  10. How air influences radiation dose deposition in multiwell culture plates: a Monte Carlo simulation of radiation geometry.

    Science.gov (United States)

    Sabater, Sebastia; Berenguer, Roberto; Honrubia-Gomez, Paloma; Rivera, Miguel; Nuez, Ana; Jimenez-Jimenez, Esther; Martos, Ana; Ramirez-Castillejo, Carmen

    2014-09-01

    Radiation of experimental culture cells on plates with various wells can cause a risk of underdosage as a result of the existence of multiple air-water interfaces. The objective of our study was to quantify this error in culture plates with multiple wells. Radiation conditions were simulated with the GAMOS code, based on the GEANT4 code, and this was compared with a simulation performed with PENELOPE and measured data. We observed a slight underdosage of ? 4% on the most superficial half of the culture medium. We believe that this underdosage does not have a significant effect on the dose received by culture cells deposited in a monolayer and adhered to the base of the wells. PMID:24722683

  11. How air influences radiation dose deposition in multiwell culture plates. A Monte Carlo simulation of radiation geometry

    International Nuclear Information System (INIS)

    Radiation of experimental culture cells on plates with various wells can cause a risk of underdosage as a result of the existence of multiple air-water interfaces. The objective of our study was to quantify this error in culture plates with multiple wells. Radiation conditions were simulated with the GAMOS code, based on the GEANT4 code, and this was compared with a simulation performed with PENELOPE and measured data. We observed a slight underdosage of ∼4% on the most superficial half of the culture medium. We believe that this underdosage does not have a significant effect on the dose received by culture cells deposited in a monolayer and adhered to the base of the wells. (author)

  12. Biologically based multistage modeling of radiation effects

    Energy Technology Data Exchange (ETDEWEB)

    William Hazelton; Suresh Moolgavkar; E. Georg Luebeck

    2005-08-30

    This past year we have made substantial progress in modeling the contribution of homeostatic regulation to low-dose radiation effects and carcinogenesis. We have worked to refine and apply our multistage carcinogenesis models to explicitly incorporate cell cycle states, simple and complex damage, checkpoint delay, slow and fast repair, differentiation, and apoptosis to study the effects of low-dose ionizing radiation in mouse intestinal crypts, as well as in other tissues. We have one paper accepted for publication in ''Advances in Space Research'', and another manuscript in preparation describing this work. I also wrote a chapter describing our combined cell-cycle and multistage carcinogenesis model that will be published in a book on stochastic carcinogenesis models edited by Wei-Yuan Tan. In addition, we organized and held a workshop on ''Biologically Based Modeling of Human Health Effects of Low dose Ionizing Radiation'', July 28-29, 2005 at Fred Hutchinson Cancer Research Center in Seattle, Washington. We had over 20 participants, including Mary Helen Barcellos-Hoff as keynote speaker, talks by most of the low-dose modelers in the DOE low-dose program, experimentalists including Les Redpath (and Mary Helen), Noelle Metting from DOE, and Tony Brooks. It appears that homeostatic regulation may be central to understanding low-dose radiation phenomena. The primary effects of ionizing radiation (IR) are cell killing, delayed cell cycling, and induction of mutations. However, homeostatic regulation causes cells that are killed or damaged by IR to eventually be replaced. Cells with an initiating mutation may have a replacement advantage, leading to clonal expansion of these initiated cells. Thus we have focused particularly on modeling effects that disturb homeostatic regulation as early steps in the carcinogenic process. There are two primary considerations that support our focus on homeostatic regulation. First, a number of epidemiologic studies using multistage carcinogenesis models that incorporate the ''initiation, promotion, and malignant conversion'' paradigm of carcinogenesis are indicating that promotion of initiated cells is the most important cellular mechanism driving the shape of the age specific hazard for many types of cancer. Second, we have realized that many of the genes that are modified in early stages of the carcinogenic process contribute to one or more of four general cellular pathways that confer a promotional advantage to cells when these pathways are disrupted.

  13. Modeling and simulation of metal-air batteries

    Science.gov (United States)

    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.

  14. Sensitivity analysis of health risk assessments air quality modeling

    International Nuclear Information System (INIS)

    The use of a health risk assessment (HRA) as a decision making tool has increased dramatically over the last few years. As such, the science and methodology that is required to complete a HRA has taken on a greater level of refinement. The completion of a HRA requires many different disciplines including process engineering, source and ambient air testing, meteorology, air quality modeling, chemistry and toxicology. Each one of these disciplines will have an impact on the final results of an HRA. As a brief overview, an HRA can be separated into the following major area of analysis: Estimates of the chemicals that are emitted and their associated emission rates; Air emission source characteristics, i.e., stack height, stack gas temperature, etc.; Physical setting of the area surrounding the source; Analysis of the local meteorology;Analysis of the downwind atmospheric dispersion; The population characteristics in the surrounding area; Environmental fate of the emitted chemical(s) and population exposure;and Analysis of health risk. Each of these areas will effect the final results. The purpose of the article is to address some of the impacts that an air quality modeling analysis can have on the final HRA results. The relative impacts of the air quality modeling results will be shown by completing a sensitivity analysis of various modeling parameters that are commonly encountered when evaluating the downwind air quality impacts for an HRA. Specifically, the authors evaluate the sensitivity of an HRA air quality modeling analysis to the following parameters: Screening level model analysis versus actual one-year model simulations; Atmospheric deposition rate; and Aerodynamic surface roughness

  15. Quantitative assessment of radiation force effect at the dielectric air-liquid interface

    OpenAIRE

    Otávio Augusto Capeloto; Vitor Santaella Zanuto; Luis Carlos Malacarne; Mauro Luciano Baesso; Gustavo Vinicius Bassi Lukasievicz; Stephen Edward Bialkowski; Nelson Guilherme Castelli Astrath

    2016-01-01

    We induce nanometer-scale surface deformation by exploiting momentum conservation of the interaction between laser light and dielectric liquids. The effect of radiation force at the air-liquid interface is quantitatively assessed for fluids with different density, viscosity and surface tension. The imparted pressure on the liquids by continuous or pulsed laser light excitation is fully described by the Helmholtz electromagnetic force density.

  16. Air-crew exposure to cosmic radiation on board of Polish passenger aircraft

    International Nuclear Information System (INIS)

    To establish the need for individual monitoring of air crew, exposure of air-crew members of Polish airlines - LOT to cosmic radiation has been determined and several dosimetry methods tested in flight. Passive radiation dosimetry (using thermoluminescent LiF and chemically etched CR-39 detectors) Was supported by calculations with the CARI computer code. We found that the air crew of most of the LOT aircraft studied (with exception of those flying ATR propeller aircraft) may somewhat exceed or, in certain conditions (depending on solar activity), may considerably exceed the effective dose level if 1 mSv per year. For crew members flying regularly on B-767 aircraft, the estimated yearly effective dose ranged between 2 mSv and and 5 mSv, depending mainly on flying frequency and solar activity. During periods of enhanced intensity of cosmic radiation (i.e. during minimum solar activity) the effective dose could be close to the level of 6 mSv per year. (author)

  17. Measuring Air Temperature in Glazed Ventilated Facades in the Presence of Direct Solar Radiation

    DEFF Research Database (Denmark)

    Kalyanova, Olena; Zanghirella, Fabio; Heiselberg, Per; Perino, Marco; Jensen, Rasmus Lund

    2007-01-01

    A distinctive element of buildings with a double glazed façade is naturally or mechanically driven flow in a ventilated cavity. Accurate air temperature measurements in the cavity are crucial to evaluate the dynamic performance of the façade, to predict and control its behavior as a significant...... part of the complete ventilation system. Assessment of necessary cooling/heating loads and of the whole building energy performance will then depend on the accuracy of measured air temperature. The presence of direct solar radiation is an essential element for the façade operation, but it can heavily...... affect measurements of air temperature and may lead to errors of high magnitude using bare thermocouples and even adopting shielding devices. Two different research groups, from Aalborg University and Politecnico di Torino, tested separately various techniques to shield thermocouples from direct...

  18. Modeling noise annoyance caused by air traffic using fuzzy logic

    OpenAIRE

    Sanchez Franco, Miriam

    2008-01-01

    The main goal of this project is the study and modeling of the noise annoyance caused by air traffic by using the fuzzy logic theory. Like many other environmental problems, air traffic noise, continues to grow and has become a serious problem in many countries. Millions of people living or working around airport areas can suffer from noise exposure effects as for instance hearing loss, interference with communication, stress, sleep disturbance, psychological effects as well...

  19. Meteorological and air pollution modeling for an urban airport

    Science.gov (United States)

    Swan, P. R.; Lee, I. Y.

    1980-01-01

    Results are presented of numerical experiments modeling meteorology, multiple pollutant sources, and nonlinear photochemical reactions for the case of an airport in a large urban area with complex terrain. A planetary boundary-layer model which predicts the mixing depth and generates wind, moisture, and temperature fields was used; it utilizes only surface and synoptic boundary conditions as input data. A version of the Hecht-Seinfeld-Dodge chemical kinetics model is integrated with a new, rapid numerical technique; both the San Francisco Bay Area Air Quality Management District source inventory and the San Jose Airport aircraft inventory are utilized. The air quality model results are presented in contour plots; the combined results illustrate that the highly nonlinear interactions which are present require that the chemistry and meteorology be considered simultaneously to make a valid assessment of the effects of individual sources on regional air quality.

  20. Air kerma national standard of Russian Federation for x-ray and gamma radiation. Activity SSDL/VNIIM in medical radiation dosimetry field

    International Nuclear Information System (INIS)

    Primary standard of unities air kerma and air kerma rate X-ray and gamma radiation, placed at VNIIM, consists of: plate-parallel free-air ionization chamber IK 10-60 for low-energy X-ray in the generating potential range from 10 to 50 kV; plate-parallel free-air ionization chamber IK 50-400 for medium-energy X-ray in the generating potential range from 50 to 300 kV; cavity cylindrical graphite chambers C1 and C30 with volumes 1 cm3 and 30 cm3 for reproduction and transmission the dimensions gamma radiation unities using Cs-137 and Co-60 sources. The next irradiation facilities are used at VNIIM: in low-energy X-ray range: a constant-potential high-voltage generator and a tungsten-anode Xray tube with inherent filtration of around 1 mm Be; in medium-energy X-ray range: set on the basis of an industrial X-ray apparatus Isovolt-400 and a tungsten-anode X-ray tube with inherent filtration of around 3,5 mm Al; in gamma radiations field: units with a radioactive sources Cs-137 with activity 140 and 1200 GBq and Co-60 with activity 120 GBq and irradiation set with a source from Co-60 (activity 3200 GBq). The last one belongs to Central Research Institute for Radiology and Roentgenology (CNIRRI). For measuring currents and charges of standard chambers we use electrometers such as Keithley of model 6517A and B7-45 manufactured by 'Belvar' (Republic Belarus). The reference radiation qualities L, N, H series according to ISO 4037 and the radiation qualities RQR, RQA and RQF according to IEC 61267 for calibration and verification of the therapeutic, diagnostic measurement means are realized in the low-energy and medium-energy X-ray standards. The VNIIM air kerma primary standard of has been participated in the international comparisons: key comparison BIPM.R1(I)-K1 for gamma radiation of Co-60 in 1997; supplementary comparisons BIPM.R1(I)-S10 for gamma radiation of Cs-137 in 1997; key comparison BIPM.R1(I)-K2 for low-energy X-ray range in 1998; key comparison BIPM.R1(I)-K3 for medium-energy X-ray range in 1998. The results of comparisons are presented in the table 1. Dimensions of unities of air kerma and air kerma rate are transmitted from primary standard to secondary standards with expanded uncertainty from 1,3 to 2,5 % (k=2), which are including and at laboratory SSDL/VNIIM and base dosimetry laboratory CNIRRI. The comparisons of secondary standards with the primary standard VNIIM are performed one time in 5 years. The laboratory SSDL/VNIIM is the component of state primary standards laboratory in the field of measurement ionizing radiations VNIIM. SSDL/VNIIM has the secondary standard - universal dosimeter UNIDOS with ionization chambers of volume from 0,6 cm3 to 10 liters, radioactive sources from Fe-55, Cd-109, Am-241, Cs-137 and Co-60 with activity from 0,03 to 140 GBq. The primary standard equipment and facility on the basis industrial X-ray apparatus YRD-1 with a tungsten-anode X-ray tube and inherent filtration of around 3 mm Al (at generating potential from 50 to 250 kV) are used for calibration dosimetric devices in the field X-ray. There is termoluminescence dosimetric system such as KDT-02M with TL detectors from LiF for spending audit measurements by method 'dose-post'. Laboratory SSDL/VNIIM and base dosimetric laboratory CNIRRI are carried out calibrations and verifications of air kerma and air kerma rate reference standards and working measurement means for X-ray and gamma therapy and diagnostics, belonging to the oncology and diagnostic centers, clinics and hospitals. The laboratory CNIRRI fulfils the verification of measurement means and supervision of the application in the medical radiology, but the regional departments of radial diagnostics put into practice monitoring of doses, obtained by patients and staff at fulfilling of diagnostic and medical procedures. The diagnostic and clinical dosimeters are calibrated directly under the primary standard of air kerma and air kerma rate for achievement the highest accuracy. At 2000-2001 this calibrations were carried out for the Belarusian Research Institute of Oncology and Medical Radiology, Belarusian Center of the Standards, Standardization and Metrology, Kaliningrad regional hospital, Research Institute of Oncology by N.N.Petrov (St. Petersburg). The laboratory SSDL/VNIIM takes part in the programs of IAEA and team works with the St. Petersburg Research Institute of Physics Health, inspection of doses, let going to the patients at medical procedures, and also spends trials of the new native and foreign dosimetric equipment, applied in medicine

  1. Modeling of an electrically rechargeable alkaline zinc-air battery

    Energy Technology Data Exchange (ETDEWEB)

    Deiss, E.; Holzer, F.; Haas, O.

    2003-03-01

    A numerical model has been developed to simulate the charging and discharge behaviour of an electrically rechargeable alkaline zinc-air battery. Further a galvanostatic experiment including three charge/discharge cycles has been performed. The cell voltages, the Zn electrode potentials versus a Zn reference, and the O{sub 2} electrode potentials versus a Zn reference calculated with the model are in fairly good agreement with the corresponding experimental data. The model is expected to be useful for zinc-air battery design and for analysis of experimental data. (author)

  2. Modeling air entrainment in plunging jet using 3DYNAFS

    CERN Document Server

    Hsiao, Chao-Tsung; Wu, Xiongjun; Chahine, Georges L

    2011-01-01

    As the liquid jet plunges into a free surface, significant air is entrained into the water and forms air pockets. These air pockets eventually break up into small bubbles, which travel downstream to form a bubbly wake. To better understand the underlying flow physics involved in the bubble entrainment, in the linked videos, air entrainment due to a water jet plunging onto a pool of stationary water was numerically studied by using the 3DYNAFS software suit. The flow field is simulated by directly solving the Navier-Stokes equations through the viscous module, 3DYNAFS-VIS, using a level set method for capturing the free surface. The breakup of entrained air pockets and the resulting bubbly flow were modeled by coupling 3DYNAFS-VIS with a Lagrangian multi-bubble tracking model, 3DYNAFS-DSM (Hsiao & Chahine, 2003), which emits bubbles into the liquid according to local liquid/gas interface flow conditions based on the sub-grid air entrainment modeling proposed by Ma et al. (2011), and tracks all bubbles in t...

  3. Air flow modelling in deep wells: application to mining ventilation

    OpenAIRE

    Witrant, Emmanuel; Johansson, Karl Henrik

    2008-01-01

    In this paper, we present a novel air flow modeling strategy for deep wells that is suitable for real-time control of large-scale systems. We consider the mining ventilation control application, where specifically designed models are crucial for new automation strategies based on global system control and energy consumption optimization. Two different levels of complexity are proposed. Starting from a general model based on Navier- Stokes equations, we derive a 0-D, Bond Graph model. This mod...

  4. Parameterization of a simple model to estimate monthly global solar radiation based on meteorological variables, and evaluation of existing solar radiation models for Tabouk, Saudi Arabia

    International Nuclear Information System (INIS)

    Using 9 years of solar radiation data, we established a simple model to calculate the monthly mean global solar radiation on a horizontal surface in Tabouk (28.38 deg. N, 36.6 deg. E, Saudi Arabia). The model correlates the global solar radiation with five meteorological parameters. These parameters are the perceptible water vapor, air temperature, relative humidity, atmospheric pressure, and the mean monthly daily fraction of possible sunshine hours. The estimated global radiation from the model was compared with the measured values using the mean bias error (MBE), coefficient of correlation (R), root mean square error (RMSE), and mean percentage error (MPE). The t statistics were also applied as another indication of suitability. The model has a high coefficient of correlation (R = 0.99), MBE = -14 x 10-4 kW h/m2, RMSE = 0.10 kW h/m2, and MPE = -0.03%. It is believed that the model developed in this work is applicable for estimating, with great accuracy. The monthly mean daily global radiation at any site having similar conditions to those found in Tabouk. Furthermore, 29 regression models available in the literature were used to estimate the global solar radiation data for Tabouk. The selected models were different in terms of the variables they use and in the number of the variables they contained. The models were compared on the basis of the statistical errors considered above. Apart from Abdall's model, which showed a reasonable estimate (MPE = -2.04%, MBE = -0.22 kW h/m2, and RMSE = 0.59 kW h/m2), all the models under or overestimate the measured solar radiation values. Comparisons between these models and the produced model, from this study, were also considered. According to the statistical results, the model of Abdall showed the prediction closest to those estimated using the developed model.

  5. Comparison and analysis of radiation hydrodynamic models

    International Nuclear Information System (INIS)

    Given the lack of consensus on transport-based radiation hydrodynamic models from the literature, we present a comparative study of these models based on their mathematical properties. We are particularly interested in the following properties: (1) conservation of momentum and energy, (2) accuracy of co-moving effects, (3) existence of a consistent mathematical entropy and (4) correct diffusion limit. The study focuses on the so-called 'mixed-frame' models and the 'PN' (spherical harmonics) approximation of the transport operator. We identify defects (of conservation or entropy) on existing models and propose an entropic correction leading to a PN model satisfying all the mathematical properties listed above, for both Newtonian and relativistic hydrodynamic regimes. (author)

  6. FUNDAMENTAL MASS TRANSFER MODELS FOR INDOOR AIR POLLUTION SOURCES

    Science.gov (United States)

    The paper discusses a simple, fundamental mass transfer model, based on Fick's Law of Diffusion, for indoor air pollution wet sorbent-based sources. (Note: Models are needed to predict emissions from indoor sources. hile empirical approaches based on dynamic chamber data are usef...

  7. RELMAP: A REGIONAL LAGRANGIAN MODEL OF AIR POLLUTION - USER'S GUIDE

    Science.gov (United States)

    The regional Lagrangian Model of Air Pollution (RELMAP) is a mass conserving, Lagrangian model that simulates ambient concentrations and wet and dry depositions of SO2, SO4=, and fine and coarse particulate matter over the eastern United States and southeastern Canada (default do...

  8. AIR POLLUTION MODELS AS DESCRIPTORS OF CAUSE-EFFECT RELATIONSHIPS

    Science.gov (United States)

    The problem of air pollution modeling is treated beginning from a philosophical standpoint, in which a model is viewed as a universal statement and a complementary set of singular statements from which specific cause-effect relationships are deduced; proceeding to the formulation...

  9. On the valence model for radiative capture

    International Nuclear Information System (INIS)

    We give several parametrizations for the elastic scattering and radiative capture cross sections for low neutron bombarding energy and discuss the relationship between the corresponding resonance parameters. We then peform an extensive investigation of the valence radiative capture model of Lane and Lynn. This model is formulated here in the frame of the shell-model approach. We exhibit the similarities and differences between our results and those derived from the R-matrix approach by Lane and Lynn on the one hand and from the optical-model approach by Lane and Mughabghab on the other hand. Particular attention is paid to the choice of the average potential well in the shell model approach, in relation to the proper way to identify theoretical quantities and phenomenological parameters. We show that practically equivalent results can be obtained from a complex average potential well and from a suitably chosen real potential well. The following topics are investigated formally and numerically: dependence of the various theoretical expressions on the choice of the (real or complex) average potential well; relative importance of external and internal capture; dependence of photon widths and background cross section on mass number (for thermal energy and for E=100 keV); dependence of the resonance parameters and background cross sections on energy, for A=60; comparison between experimental data and theoretical values for radiative capture on 56Fe and 60Ni. We discuss the conditions of validity of the valence capture model The contribution of the low-lying excited target states is investigated formally and numerically

  10. Sensitivity/uncertainty analysis for free-in-air tissue kerma due to initial radiation at Hiroshima and Nagasaki

    International Nuclear Information System (INIS)

    Uncertainty estimates and cross correlations by range/survivor have been calculated for the Hiroshima and Nagasaki free-in-air (FIA) tissue kerma obtained from two-dimensional air/ground transport calculations. The uncertainties due to modeling parameter and basic nuclear transport data uncertainties were calculated for 700-, 1000-, and 1500-m ground ranges. Only the FIA tissue kerma due to initial radiation was treated in the analysis; the uncertainties associated with terrain and building shielding and phantom attenuation were not considered in this study. Uncertainties of --20% were obtained for the prompt neutron and secondary gamma kerma and 30% for the prompt gamma kerma at both cities. The uncertainties on the total prompt kerma at Hiroshima and Nagasaki are --18 and 15%, respectively. The estimated uncertainties vary only slightly by ground range and are fairly highly correlated. The total prompt kerma uncertainties are dominated by the secondary gamma uncertainties, which in turn are dominated by the modeling parameter uncertainties, particularly those associated with the weapon yield and radiation sources

  11. The impact of diurnal variations of air traffic on contrail radiative forcing

    Directory of Open Access Journals (Sweden)

    N. Stuber

    2007-06-01

    Full Text Available We combined high resolution aircraft flight data from the EU Fifth Framework Programme project AERO2k with analysis data from the ECMWF's integrated forecast system to calculate diurnally resolved 3-D contrail cover. We scaled the contrail cover in order to match observational data for the Bakan area (eastern-Atlantic/western-Europe.

    We found that less than 40% of the global distance travelled by aircraft is due to flights during local night time. Yet, due to the cancellation of shortwave and longwave effects during daytime, night time flights contribute a disproportional 60% to the global annual mean forcing. Under clear sky conditions the night flights contribute even more disproportionally at 76%. There are pronounced regional variations in night flying and the associated radiative forcing. Over parts of the North Atlantic flight corridor 75% of air traffic and 84% of the forcing occurs during local night, whereas only 35% of flights are during local night in South-East Asia, yet these contribute 68% of the radiative forcing. In general, regions with a significant local contrail radiative forcing are also regions for which night time flights amount to less than half of the daily total of flights. Therefore, neglecting diurnal variations in air traffic/contrail cover by assuming a diurnal mean contrail cover can over-estimate the global mean radiative forcing by up to 30%.

  12. A theoretical investigation to study the effect of air pollution on global solar radiation

    International Nuclear Information System (INIS)

    The ratio of measured solar radiation for normal and clear sky G and G0, known an ''clearness index'' is as an indicator for air pollutant mass loading. In the present work, estimated clear sky global solar radiation G0 for cairo city is compared graphically with measured actual solar radiation G for normal sky with atmospheric aerosols and pollution. The clearness index (G/G0) and its empirical coefficients which vary from place to place to place are examined in order to derive a suitable formula for cairo city relating these coefficients. In this study, the well known angstrom equation in its linear form together with measured monthly means of the daily global solar radiation data are used for function fitting procedure to derive a linear semi-empirical formula relating the clearness ined coefficients (the error is of value 5%). For daily values of measured global solar radiation, an extension of the angstrom equation in a non-linear form is assumed and a polynomial regression is used for curve fitting to obtain a corresponding semi-empirical relation between the clearness index coefficients (the error is 3%). The paper ends with the result that the nonlinear graph seems to be reasonably accurate and is recommended to estimate the global solar radiation G for Cairo city

  13. MODEL DINAMIK PENGENDALIAN PENCEMARAN AIR KALI SURABAYA

    Directory of Open Access Journals (Sweden)

    Suwari Suwari

    2011-08-01

    Full Text Available The Surabaya River plays an important role as water supply of the Surabaya PDAM, irrigation, industry, transportation, and means of recreation. However, domestic, industrial, and agricultural waste that were discharged into the river stream polluted the Surabaya River and decreased the carrying capacity and assimilative capacity. Therefore, effort to monitor and control the Surabaya River water pollution need to be well organized and implemented. The aim of the research is to develop a model of water pollution control on Surabaya River region. The research was carried out based on field survey, in situ and laboratory sample examination, questionnaire, and expert judgment. Pollution control model developed in this study was built into three sub-models, namely: (1 ecology sub-model, (2 social sub-model, and (3 economy sub-model using powersim constructor 2.5 version. Pollution control scenarios were developed using prospective analysis. The results of water pollution parameters such as TSS, DO, BOD, COD, N-NO2, and the level of mercury (Hg were higher than the allowable class 1 standard. The sources of Surabaya River pollution mainly are domestic and industrial waste with total load of BOD, COD, and TSS are 55.49, 132.58, and 210.13 ton/day, respectively. According to water quality status, the Surabaya River is categorized as heavy polluted and the loading pollution need to be decreased. By using prospective analysis, there were five important factors that affect the future of the Surabaya River water pollution control, i.e.: (1 population growth and community awareness, (2 community perception, (3 implementation of regulations, (4 commitment/local government support, and (5 system and institutional capacity. There are three development scenarios, that are pessimistic, moderate and optimistic. The moderate and optimistic scenario are the realistic scenarios that occur in the future for Surabaya River water pollution control in considering of ecology, social and economy aspects.

  14. Dimuon radiation from a hybrid evolution model

    Energy Technology Data Exchange (ETDEWEB)

    Santini, Elvira [Institut fuer Theoretische Physik, Goethe-Universitaet, Frankfurt (Germany); Bleicher, Marcus [Institut fuer Theoretische Physik, Goethe-Universitaet, Frankfurt (Germany); Frankfurt Institute for Advanced Studies (FIAS) (Germany)

    2011-07-01

    We analyze dilepton emission from hot and dense matter created in heavy-ion collisions using a hybrid approach based on the UrQMD transport model with an intermediate hydrodynamic stage for the modeling of heavy-ion dynamics. During the hydrodynamic stage dilepton emission from hadronic and quark-gluon matter is described by radiation rates for a strongly interacting medium in thermal equilibrium. Focusing on the enhancement with respect to the contribution from long-lived hadron decays after freeze-out observed at the SPS in the dilepton spectra the relative importance of the various sources is discussed. A comparison to NA60 data is performed.

  15. Modeling and Treatment of Radiation Cystitis.

    Science.gov (United States)

    Zwaans, Bernadette M M; Chancellor, Michael B; Lamb, Laura E

    2016-02-01

    Radiation cystitis (RC) is a debilitating condition that, if not managed at an early stage, can have a major impact on the quality of life of a patient and can lead to severe hemorrhaging and even death. Current treatments are focused on arresting bladder hemorrhaging, but none are able to relieve other urological symptoms associated with cystitis. There is a strong need for in-depth studies using preclinical RC models to better understand the underlying disease progression and to test novel therapies. Here we review the most commonly used therapies for RC, novel treatment strategies, and the preclinical models used to date. PMID:26571081

  16. Introductory Tools for Radiative Transfer Models

    Science.gov (United States)

    Feldman, D.; Kuai, L.; Natraj, V.; Yung, Y.

    2006-12-01

    Satellite data are currently so voluminous that, despite their unprecedented quality and potential for scientific application, only a small fraction is analyzed due to two factors: researchers' computational constraints and a relatively small number of researchers actively utilizing the data. Ultimately it is hoped that the terabytes of unanalyzed data being archived can receive scientific scrutiny but this will require a popularization of the methods associated with the analysis. Since a large portion of complexity is associated with the proper implementation of the radiative transfer model, it is reasonable and appropriate to make the model as accessible as possible to general audiences. Unfortunately, the algorithmic and conceptual details that are necessary for state-of-the-art analysis also tend to frustrate the accessibility for those new to remote sensing. Several efforts have been made to have web- based radiative transfer calculations, and these are useful for limited calculations, but analysis of more than a few spectra requires the utilization of home- or server-based computing resources. We present a system that is designed to allow for easier access to radiative transfer models with implementation on a home computing platform in the hopes that this system can be utilized in and expanded upon in advanced high school and introductory college settings. This learning-by-doing process is aided through the use of several powerful tools. The first is a wikipedia-style introduction to the salient features of radiative transfer that references the seminal works in the field and refers to more complicated calculations and algorithms sparingly5. The second feature is a technical forum, commonly referred to as a tiki-wiki, that addresses technical and conceptual questions through public postings, private messages, and a ranked searching routine. Together, these tools may be able to facilitate greater interest in the field of remote sensing.

  17. Air

    Science.gov (United States)

    ... and your health: Green living Sun Water Air Health effects of air pollution How to protect yourself from air pollution Chemicals Noise Quizzes Links to more information girlshealth glossary girlshealth.gov home http://www.girlshealth.gov/ Home The environment and your health ... Air While we don’t often think ...

  18. Initial validation of an ambient air quality model for Naval air operations

    OpenAIRE

    Douglas, Terry Scott; Netzer, David Willis

    1980-01-01

    A previously developed model was updated to appropriately represent 1978/79 operations and then evaluated for prediction sensitivity to variations in meteorological and dispersion model parameters. A joint effort with the Naval Air Propulsion Center, the Environmental Protection Agency/Northrup Services, Inc. and PMTC, Pt. Mugu was conducted to obtain detailed data over a one-week period. Much of the measured pollution concentration data (including all of the suspended particulate data) was l...

  19. Spectral modeling of radiation in combustion systems

    Science.gov (United States)

    Pal, Gopalendu

    Radiation calculations are important in combustion due to the high temperatures encountered but has not been studied in sufficient detail in the case of turbulent flames. Radiation calculations for such problems require accurate, robust, and computationally efficient models for the solution of radiative transfer equation (RTE), and spectral properties of radiation. One more layer of complexity is added in predicting the overall heat transfer in turbulent combustion systems due to nonlinear interactions between turbulent fluctuations and radiation. The present work is aimed at the development of finite volume-based high-accuracy thermal radiation modeling, including spectral radiation properties in order to accurately capture turbulence-radiation interactions (TRI) and predict heat transfer in turbulent combustion systems correctly and efficiently. The turbulent fluctuations of temperature and chemical species concentrations have strong effects on spectral radiative intensities, and TRI create a closure problem when the governing partial differential equations are averaged. Recently, several approaches have been proposed to take TRI into account. Among these attempts the most promising approaches are the probability density function (PDF) methods, which can treat nonlinear coupling between turbulence and radiative emission exactly, i.e., "emission TRI". The basic idea of the PDF method is to treat physical variables as random variables and to solve the PDF transport equation stochastically. The actual reacting flow field is represented by a large number of discrete stochastic particles each carrying their own random variable values and evolving with time. The mean value of any function of those random variables, such as the chemical source term, can be evaluated exactly by taking the ensemble average of particles. The local emission term belongs to this class and thus, can be evaluated directly and exactly from particle ensembles. However, the local absorption term involves interactions between the local particle and energy emitted by all other particles and, hence, cannot be obtained from particle ensembles directly. To close the nonlinear coupling between turbulence and absorption, i.e., "absorption TRI", an optically thin fluctuation approximation can be applied to virtually all combustion problems and obtain acceptable accuracy. In the present study a composition-PDF method is applied, in which only the temperature and the species concentrations are treated as random variables. A closely coupled hybrid finite-volume/Monte Carlo scheme is adopted, in which the Monte Carlo method is used to solve the composition-PDF for chemical reactions and the finite volume method is used to solve for the flow field and radiation. Spherical harmonics method-based finite volume solvers (P-1 and P-3) are developed using the data structures of the high fidelity open-source code flow software OpenFOAM. Spectral radiative properties of the participating medium are modeled using full-spectrum k-distribution methods. Advancements of basic k-distribution methods are performed for nongray nonhomogeneous gas- and particulate-phase (soot, fuel droplets, ash, etc.) participating media using multi-scale and multi-group based approaches. These methods achieve close-to benchmark line-by-line (LBL) accuracy in strongly inhomogeneous media at a tiny fraction of LBL's computational cost. A portable spectral module is developed, which includes all the basic to advanced k-distribution methods along with the precompiled accurate and compact k-distribution databases. The P-1 /P-3 RTE solver coupled with the spectral module is used in conjunction with the combined Reynolds-averaged Navier-Stokes (RANS) and composition-PDF-based turbulence-chemistry solver to investigate TRI in multiphase turbulent combustion systems. The combustion solvers developed in this study is employed to simulate several turbulent jet flames, such as Sandia Flame D, and artificial nonsooting and sooting flames derived from Flame D. The effects of combustion chemistry, radiation and TRI on total heat transfer and pollutant (such as NO x) generation are studied for the above flames. The accuracy of the overall combustion solver is assessed by comparing it with the experimental data for Flame D. Comparison of the accuracy and the computational cost among various spectral models and RTE solvers is extensively done on the artificial flames derived from Flame D to demonstrate the necessity of accurate modeling of radiation in combustion problems.

  20. Refined weighted sum of gray gases model for air-fuel combustion and its impacts

    DEFF Research Database (Denmark)

    Yin, Chungen

    2013-01-01

    in computational fluid dynamics (CFD) simulation of air-fuel combustion processes. It represents a reasonable compromise between an oversimplified gray gas model and a comprehensive approach addressing high-resolution dependency of radiative properties and intensity upon wavelength. The WSGGM...... recommended for use in CFD simulation of any air-fuel combustion process because of its greater accuracy, completeness, and applicability....... coefficients evaluated by Smith et al. for several partial pressures of CO2 and H2O vapor are often used for gas temperatures up to 2400 K, which is supplemented by the coefficient values presented by Coppalle and Vervisch for higher temperatures until 3000 K. This paper refines the air-fuel WSGGM in terms of...

  1. The influence of gas radiation on the thermal behavior of a 2D axisymmetric turbulent non-premixed methane–air flame

    International Nuclear Information System (INIS)

    Highlights: • The study evaluates the importance of thermal radiation in a methane–air flame. • The radiative properties are treated with the WSGG based on HITEMP 2010. • The turbulence–radiation interaction (TRI) is based on a RANS approach. • Radiation strongly affected the temperature field but not the chemical composition. • Neglecting TRI led to a lower estimate of the radiation heat transfer. - Abstract: This paper presents a study of the effect of thermal radiation in the simulation of a turbulent, non-premixed methane–air flame. In such a problem, two aspects need to be considered for a precise evaluation of the thermal radiation: the turbulence–radiation interactions (TRI), and the local variation of the radiative properties of the participating species, which are treated here with the weighted-sum-of-gray-gases (WSGG) model based on newly obtained correlations from HITEMP2010 database. The chemical reactions rates were considered as the minimum values between the Arrhenius and Eddy Break-Up rates. A two-step global reaction mechanism was used, while the turbulence modeling was considered via standard k–ε model. The source terms of the energy equation consisted of the heat generated in the chemical reaction rates as well as in the radiation exchanges. The discrete ordinates method (DOM) was employed to solve the radiative transfer equation (RTE), including the TRI. Comparisons of simulations with/without radiation (which in turn was solved with/without TRI) demonstrated that the temperature, the radiative heat source, and the wall heat flux were importantly affected by thermal radiation, while the influence on species concentrations proved to be negligible. Inclusion of thermal radiation led to results that were closer to experimental data available in the literature for the same test case considered in this paper. Inclusion of TRI improved the agreement, although in a smaller degree. The main influence of TRI was mainly on global results, such as the peak temperature and the radiant fraction. The results show the importance of thermal radiation for an accurate prediction of the thermal behavior of a combustion chamber

  2. A Hybrid Neural Network Prediction Model of Air Ticket Sales

    Directory of Open Access Journals (Sweden)

    Han-Chen Huang

    2013-11-01

    Full Text Available Air ticket sales revenue is an important source of revenue for travel agencies, and if future air ticket sales revenue can be accurately forecast, travel agencies will be able to advance procurement to achieve a sufficient amount of cost-effective tickets. Therefore, this study applied the Artificial Neural Network (ANN and Genetic Algorithms (GA to establish a prediction model of travel agency air ticket sales revenue. By verifying the empirical data, this study proved that the established prediction model has accurate prediction power, and MAPE (mean absolute percentage error is only 9.11%. The established model can provide business operators with reliable and efficient prediction data as a reference for operational decisions.

  3. Theoretical method for calculating solar radiation in terms of air temperature or sunshine duration using fourier series

    International Nuclear Information System (INIS)

    Because of the periodicity of variations in solar radiation 'R', air temperature 'T' and sunshine duration 'S', their values are expanded in fourier series. Fourier coefficients are determined by using measured meteorological data of the selected egyptian weather stations. These coefficients are used to calculate solar radiation is presented in tables and graphs. The comparison shows a good agreement between the observed and estimated solar radiation. The method is applied to calculate the solar radiation for another stations where solar radiation measurements are unavailable, using records of air temperature or sunshine duration at these stations and solar radiation measured at the nearest meteorological stations. The estimated global solar radiation at any area is used to know the atmospheric stability, which is used to calculate the dispersion of pollutants in this area

  4. Extensive Air Showers Model Dependence And The Longitudinal Profile

    CERN Document Server

    Mikulski, P T

    2000-01-01

    The physics of atmospheric cascades induced by ultrahigh energy cosmic rays above the GZK cutoff is investigated. A flexible air shower generator is developed for the exploration of air shower properties under various assumptions about the underlying hadronic physics. Included is an efficient algorithm for the simulation of electromagnetic cascades which emphasizes consistency with the standard Greisen formula for photons. The uncertainties in hadronic interaction physics relevant to air shower properties are bracketed with conservative models which characterize limiting scenarios. The effects of scaling violations in hadron-nucleon and hadron- nucleus iteractions are addressed. Emphasis is on the fragmentation region which is of most relevance to air shower development. The physics uncertainties imply an uncertainty in the average depth at maximum for proton induced cascades at the highest energies which is comparable to the separation between protons and iron. Consequently, it will be difficult to extract i...

  5. A comparison of model predictions and observations of the transfer of 137Cs through the air-pasture-cow-milk pathway

    International Nuclear Information System (INIS)

    Environmental measurements following the Chernobyl accident for selected locations in the United States and Europe were compared with model predictions of the transfer of 137Cs through the air-pasture-cow-milk pathway. The models include IAEA Safety Series No. 57, AIRDOS/EPA, NRC Regulatory Guides 1.109 and 1.111, the National Council on Radiation Protection and Measurements (NCRP) screening model, and the PATHWAY dynamic food-chain model. Time integrals of the 137Cs concentrations in air, pasture, and milk were estimated, and the predicted and observed grass/air, milk/air, and milk/grass concentration ratios were compared. (author)

  6. Mathematical models for atmospheric pollutants. Appendix D. Available air quality models. Final report

    International Nuclear Information System (INIS)

    Models that are available for the analysis of airborne pollutants are summarized. In addition, recommendations are given concerning the use of particular models to aid in particular air quality decision making processes. The air quality models are characterized in terms of time and space scales, steady state or time dependent processes, reference frames, reaction mechanisms, treatment of turbulence and topography, and model uncertainty. Using these characteristics, the models are classified in the following manner: simple deterministic models, such as air pollution indices, simple area source models and rollback models; statistical models, such as averaging time models, time series analysis and multivariate analysis; local plume and puff models; box and multibox models; finite difference or grid models; particle models; physical models, such as wind tunnels and liquid flumes; regional models; and global models

  7. Model-generated air quality statistics for application in vegetation response models in Alberta

    International Nuclear Information System (INIS)

    To test and apply vegetation response models in Alberta, air pollution statistics representative of various parts of the Province are required. At this time, air quality monitoring data of the requisite accuracy and time resolution are not available for most parts of Alberta. Therefore, there exists a need to develop appropriate air quality statistics. The objectives of the work reported here were to determine the applicability of model generated air quality statistics and to develop by modelling, realistic and representative time series of hourly SO2 concentrations that could be used to generate the statistics demanded by vegetation response models

  8. Dynamic modeling of an air source heat pump water heater

    OpenAIRE

    Fardoun, Farouk; Ibrahim, Oussama; Zoughaib, Assaad

    2011-01-01

    This paper presents a dynamic simulation model to predict the performance of an air source heat pump water heater (ASHPWH). The mathematical model consists of submodels of the basic system components i.e. evaporator, condenser, compressor, and expansion valve. These submodels were built based on fundamental principles of heat transfer, thermodynamics, fluid mechanics, empirical relationships and manufacturer's data as necessary. The model simulation was carried out using MATLAB software. Refr...

  9. Non-relativistic limit in a model of radiative flow

    OpenAIRE

    Nečasová, Š. (Šárka); Ducomet, B.

    2015-01-01

    We consider a “non-relativistic” limit in a model of radiative flow where matter is described by a viscous heat-conducting system coupled to radiation through the radiative transfer equation. We prove the convergence of this coupled system toward a compressible Navier–Stokes–Fourier system coupled to a stationary radiative transfer equation.

  10. Measurement and simulation of the in-flight radiation exposure on different air routes

    International Nuclear Information System (INIS)

    The exposure of air-crew personnel to cosmic radiation is considered to be occupational exposure and requirements for dose assessment are given in the European Council Directive 96/29/EURATOM. The High-Temperature Ratio (HTR) Method for LiF: Mg, Ti TLDs utilizes the well-investigated relative intensity of the combined high-temperature glow peaks 6 and 7 compared with the dominant peak 5 (left-hand side of Figure 1) as an indication of the dose-average LET of a mixed radiation field of unknown composition. The difference in the peak-5 readings of the neutron-sensitive TLD-600 (6LiF: Mg, Ti) and the neutron-insensitive TLD-700 (7LiF: Mg, Ti) can be utilized to assess the neutron dose equivalent accumulated in-flight. For this purpose, the dosemeter crystals were calibrated individually in the CERN-EU High Energy Reference Field (CERF) [8] which simulates the cosmic-ray induced neutron spectrum in good detail. The experiments conducted onboard passenger aircraft on different north-bound and trans-equatorial flight routes were aimed at the following: to measure the total dose equivalent accumulated during the flight, to assess the contribution of neutrons, and to compare the results with calculations by means of the well-known CARI computer code. Measurements were performed on a series of eight north-bound flights between Cologne and Washington as well as on the routes Vienna-Atlanta, Vienna-Sydney and Vienna-Tokyo during different solar activity conditions. Precise altitude and route profiles were recorded by the pilots. The experimental results were compared with model calculations using the latest release 6M of the CARI code. Precise altitude and route data on a ten-minute to one-hour scale were taken as input. The calculated dose values indicate that the algorithms employed for the computational assessment of route doses have been significantly improved during the last decade. The CARI results generally tend to be in reasonable agreement with the measured values, although the doses for north-bound flights during solar minimum might still be underestimated by up to 15 %. The most important insufficiency in all computational approaches regards the effects of major solar particle events (SPEs) presenting a serious danger primarily for future high-altitude and polar-orbital flights in causing severe biological hazards. The frequency of these irregular events corresponds to the solar activity cycle. This fact is taken into account in the codes by semi-empirical models which certainly have to fail in forecasting accurate dose values for a specific flight. Therefore, dosimetric surveillance of air-crew members would be essential and cannot be completely replaced by calculations. (authors)

  11. Data assimilation for air quality models

    DEFF Research Database (Denmark)

    Silver, Jeremy David

    2014-01-01

    , observations of one chemical species can be used to adjust concentrations of other (unobserved) species. Most of the methodology used in data assimilation for CTMs is based on developments within the field of numerical weather prediction, where multiparameter assimilation schemes are the norm. The verification...... chemical and physical dynamics. Concentrations of atmospheric trace gases such as ozone, carbon monoxide and nitrogen dioxide vary substantially in space and time, and this variation can be investigated by various methods including direct measurements, remote-sensing measurements and atmospheric chemistry......-transport models (CTMs). Each of these methods has their limitations: direct measurements provide only data at point locations and may not be representative of a wider area, remotely-sensed data from polar-orbiting satellites cannot investigate diurnal variation, and CTM simulations are often associated with...

  12. Two dimensional model for coherent synchrotron radiation

    Science.gov (United States)

    Huang, Chengkun; Kwan, Thomas J. T.; Carlsten, Bruce E.

    2013-01-01

    Understanding coherent synchrotron radiation (CSR) effects in a bunch compressor requires an accurate model accounting for the realistic beam shape and parameters. We extend the well-known 1D CSR analytic model into two dimensions and develop a simple numerical model based on the Liénard-Wiechert formula for the CSR field of a coasting beam. This CSR numerical model includes the 2D spatial dependence of the field in the bending plane and is accurate for arbitrary beam energy. It also removes the singularity in the space charge field calculation present in a 1D model. Good agreement is obtained with 1D CSR analytic result for free electron laser (FEL) related beam parameters but it can also give a more accurate result for low-energy/large spot size beams and off-axis/transient fields. This 2D CSR model can be used for understanding the limitation of various 1D models and for benchmarking fully electromagnetic multidimensional particle-in-cell simulations for self-consistent CSR modeling.

  13. Simplified model for a ventilated glass window under forced air flow conditions

    Energy Technology Data Exchange (ETDEWEB)

    Ismail, K.A.R. [Depto. de Engenharia Termica e de Fluidos-FEM-UNICAMP CP: 6122 CEP 13083-970 Campinas, SP (Brazil); Henriquez, J.R. [Depto. de Eng. Mecanica-DEMEC, UFPE Av. Academico Helio Ramos, S/N CEP 50740-530, Recife, PE (Brazil)

    2006-02-01

    This paper presents a study on a ventilated window composed of two glass sheets separated by a spacing through which air is forced to flow. The proposed model is one dimensional and unsteady based upon global energy balance over the glass sheets and the flowing fluid. The external glass sheet of the cavity is subjected to variable heat flow due to the solar radiation as well as variable external ambient temperature. The exchange of radiation energy (infrared radiation) between the glass sheets is also included in the formulation. Effects of the spacing between the glass sheets, variation of the forced mass flow rate on the total heat gain and the shading coefficients are investigated. The results show that the effect of the increase of the mass flow rate is found to reduce the mean solar heat gain and the shading coefficients while the increase of the fluid entry temperature is found to deteriorate the window thermal performance. (author)

  14. Radiative energy losses from a high-current air-blast arc

    International Nuclear Information System (INIS)

    The importance of total radiation losses from high-current arcs burning in highly accelerated air flows representative of conditions existing in commercial gas-blast switchgear has been investigated. Such losses have been measured both in the high-pressure region upstream of a shaped orifice, where gas velocities are low, and in the region downstream where velocities become supersonic and pressure conditions approach ambient. The dominance of upstream electrode vapor as the source of plasma radiation losses is demonstrated and the importance of radiated losses within the arc energy balance is examined using measured values of axial electric field. For upstream electrodes of elkonite (sintered copper/tungsten) as used in high-power gas-blast circuit breakers, it is shown that some 30--40% of the electrical energy input upstream of the orifice is lost as radiation, while downstream this figure becomes 10--20%. The effect of reservoir pressure on arc electric fields is examined and the contribution to this effect of radiation losses is quantified

  15. Solar radiation practical modeling for renewable energy applications

    CERN Document Server

    Myers, Daryl Ronald

    2013-01-01

    Written by a leading scientist with over 35 years of experience working at the National Renewable Energy Laboratory (NREL), Solar Radiation: Practical Modeling for Renewable Energy Applications brings together the most widely used, easily implemented concepts and models for estimating broadband and spectral solar radiation data. The author addresses various technical and practical questions about the accuracy of solar radiation measurements and modeling. While the focus is on engineering models and results, the book does review the fundamentals of solar radiation modeling and solar radiation m

  16. REAS3: A revised implementation of the geosynchrotron model for radio emission from air showers

    International Nuclear Information System (INIS)

    Over the past years, the freely available Monte Carlo-code REAS which simulates radio emission from air showers based on the geosynchrotron model, was used regularly for comparisons with data. However, it emerged that in the previous version of the code, emission due to the variation of the number of charged particles within an air shower was not taken into account. In the following article, we show the implementation of these emission contributions in REAS3 by the inclusion of “end-point contributions” and discuss the changes on the predictions of REAS obtained by this revision. The basis for describing radiation processes is an universal description which is gained by the use of the end-point formulation. Hence, not only pure geomagnetic radiation is simulated with REAS3 but also radiation due to the variation of the net charge excess in the air shower, independent of the Earth's magnetic field. Furthermore, we present a comparison of lateral distributions of LOPES data with REAS3-simulated distributions. The comparison shows a good agreement between both, data and REAS3 simulations.

  17. REAS3: A revised implementation of the geosynchrotron model for radio emission from air showers

    Energy Technology Data Exchange (ETDEWEB)

    Ludwig, M., E-mail: marianne.ludwig@kit.edu [Karlsruher Institut fuer Technologie, Institut fuer Experimentelle Kernphysik, Campus Sued, 76128 Karlsruhe (Germany); Huege, T. [Karlsruher Institut fuer Technologie, Institut fuer Kernphysik, Campus Nord, 76021 Karlsruhe (Germany)

    2012-01-11

    Over the past years, the freely available Monte Carlo-code REAS which simulates radio emission from air showers based on the geosynchrotron model, was used regularly for comparisons with data. However, it emerged that in the previous version of the code, emission due to the variation of the number of charged particles within an air shower was not taken into account. In the following article, we show the implementation of these emission contributions in REAS3 by the inclusion of 'end-point contributions' and discuss the changes on the predictions of REAS obtained by this revision. The basis for describing radiation processes is an universal description which is gained by the use of the end-point formulation. Hence, not only pure geomagnetic radiation is simulated with REAS3 but also radiation due to the variation of the net charge excess in the air shower, independent of the Earth's magnetic field. Furthermore, we present a comparison of lateral distributions of LOPES data with REAS3-simulated distributions. The comparison shows a good agreement between both, data and REAS3 simulations.

  18. REAS3: A revised implementation of the geosynchrotron model for radio emission from air showers

    CERN Document Server

    Ludwig, Marianne

    2010-01-01

    Over the past years, the freely available Monte Carlo-code REAS which simulates radio emission from air showers based on the geosynchrotron model, was used regularly for comparisons with data. However, it emerged that in the previous version of the code, emission due to the variation of the number of charged particles within an air shower was not taken into account. In the following article, we show the implementation of these emission contributions in REAS3 by the inclusion of ``end-point contributions'' and discuss the changes on the predictions of REAS obtained by this revision. The basis for describing radiation processes is an universal description which is gained by the use of the end-point formulation. Hence, not only pure geomagnetic radiation is simulated with REAS3 but also radiation due to the variation of the net charge excess in the air shower, independent of the Earth's magnetic field. Furthermore, we present a comparison of lateral distributions of LOPES data with REAS3-simulated distributions....

  19. Performance of the atmospheric infrared sounder (AIRS) in the radiation environment of low-earth orbit

    Science.gov (United States)

    Weiler, Margaret H.; Overoye, Kenneth R.; Stobie, James A.; O'Sullivan, Paul B.; Gaiser, Steven L.; Broberg, Steven E.; Elliott, Denis A.

    2005-08-01

    The Atmospheric Infrared Sounder (AIRS), a hyperspectral infrared sounder, was launched onboard NASA's Aqua spacecraft on May 4, 2002 into sun-synchronous polar Earth orbit for a mission expected to last 7 years. By monitoring calibration data from views of deep space and two on-board calibrators, we have identified a number of effects attributed to in-orbit radiation. Transient effects include 1. steps in the output level of individual channels, attributed to injection of charge into a large capacitor in the read-out electronics integrated circuit (ROIC); and 2. spikes in the calibration data and, by inference, in the scene data, attributed to the passage of ionizing radiation through the active region of the HgCdTe detectors. On-board signal processing corrects for most of the spike effects, and ground processing smoothes the hot and cold calibration data and provides a system of flags to alert the user in cases where the calculated radiances are still suspect. Persistent effects include 1. extremely rare degradations of channels due to large charge injection events; and 2. slow increases in noise levels for a small number of channels, attributed to bias shifts due to the slow accumulation of radiation dose in the ROIC input cells for some channels. In addition to these detector effects, two operational anomalies have been attributed to the high radiation levels in the South Atlantic Anomaly (SAA), one an unplanned cooler shut-down, the second an unplanned stopping of the scan mirror. This paper presents statistics on the frequency and location of these radiation events, and provides a description of the mechanisms by which such events are identified and accounted for. It should be emphasized that the vast majority of the 2378 AIRS infrared channels, and the instrument as a whole, have shown excellent stability and operability throughout the mission.

  20. Air-ingress analysis: Part 2-Computational fluid dynamic models

    International Nuclear Information System (INIS)

    Idaho National Laboratory (INL), under the auspices of the U.S. Department of Energy (DOE), is performing research and development that focuses on key phenomena important during potential scenarios that may occur in very high-temperature reactors (VHTRs). Phenomena identification and ranking studies to date have ranked an air-ingress event, following on the heels of a VHTR depressurization, as important with regard to core safety. Consequently, the development of advanced air-ingress-related models and verification and validation data are a very high priority. Following a loss of coolant and system depressurization incident, air will enter the core of the high-temperature gas-cooled reactor through the break, possibly causing oxidation of the core and reflector graphite structure. Simple core and plant models indicate that, under certain circumstances, the oxidation may proceed at an elevated rate with additional heat generated from the oxidation reaction itself. Under postulated conditions of fluid flow and temperature, excessive degradation of lower plenum graphite because of oxidation might lead to a reactor safety issue. Computational fluid dynamics models developed in this study will improve our understanding of this phenomenon and is used to mitigate air ingress. This paper presents three-dimensional (3D) computational fluid dynamic (CFD) results for the quantitative assessment of the air-ingress phenomena. The 3D CFD simulation results show that the air-ingress accident is not controlled by molecular diffusion but density gradient driven stratified flow when the double-ended-guillotine break is assumed in a horizontal pipe configuration. It concludes that the previous air-ingress scenarios based on the molecular diffusion might not be correct and should be extensively modified to include real phenomena. This paper also presents a preliminary two-dimensional (2D) CFD simulation for validating an air-ingress mitigation concept using helium injection at the lower plenum. This simulation shows that the helium replaces air by buoyancy force and effectively mitigates air-ingress into the core.

  1. A 331 WIMPy dark radiation model

    Energy Technology Data Exchange (ETDEWEB)

    Kelso, Chris [University of Utah, Department of Physics and Astronomy, Salt Lake City, UT (United States); Pires, C.A. de S.; Rodrigues da Silva, P.S. [Universidade Federal da Paraiba, Departamento de Fisica, Caixa Postal 5008, Joao Pessoa, PB (Brazil); Profumo, Stefano; Queiroz, Farinaldo S. [University of California, Department of Physics and Santa Cruz Institute for Particle Physics, Santa Cruz, CA (United States)

    2014-03-15

    Recent observations suggest that the number of relativistic degrees of freedom in the early universe might exceed what is predicted in the standard cosmological model. If even a small, percent-level fraction of dark matter particles are produced relativistically, they could mimic the effect of an extra realistic species at matter-radiation equality while obeying BBN, CMB and Structure Formation bounds. We show that this scenario is quite naturally realized with a weak-scale dark matter particle and a high-scale ''mother'' particle within a well-motivated 3-3-1 gauge model, which is particularly interesting for being consistent with electroweak precision measurements, with recent LHC results, and for offering a convincing explanation for the number of generations in the Standard Model. (orig.)

  2. Economic damages of ozone air pollution to crops using combined air quality and GIS modelling

    Science.gov (United States)

    Vlachokostas, Ch.; Nastis, S. A.; Achillas, Ch.; Kalogeropoulos, K.; Karmiris, I.; Moussiopoulos, N.; Chourdakis, E.; Banias, G.; Limperi, N.

    2010-09-01

    This study aims at presenting a combined air quality and GIS modelling methodological approach in order to estimate crop damages from photochemical air pollution, depict their spatial resolution and assess the order of magnitude regarding the corresponding economic damages. The analysis is conducted within the Greater Thessaloniki Area, Greece, a Mediterranean territory which is characterised by high levels of photochemical air pollution and considerable agricultural activity. Ozone concentration fields for 2002 and for specific emission reduction scenarios for the year 2010 were estimated with the Ozone Fine Structure model in the area under consideration. Total economic damage to crops turns out to be significant and estimated to be approximately 43 M€ for the reference year. Production of cotton presents the highest economic loss, which is over 16 M€, followed by table tomato (9 M€), rice (4.2 M€), wheat (4 M€) and oilseed rape (2.8 M€) cultivations. Losses are not spread uniformly among farmers and the major losses occur in areas with valuable ozone-sensitive crops. The results are very useful for highlighting the magnitude of the total economic impacts of photochemical air pollution to the area's agricultural sector and can potentially be used for comparison with studies worldwide. Furthermore, spatial analysis of the economic damage could be of importance for governmental authorities and decision makers since it provides an indicative insight, especially if the economic instruments such as financial incentives or state subsidies to farmers are considered.

  3. The Dutch standard on the description of air pollution models

    International Nuclear Information System (INIS)

    This standard establishes requirements which the description of mathematical models for air quality has to meet. The standard is applicable to models which assist in calculating the concentration of compounds in the air and/or the deposition. Users should be able to judge the usefulness of a mathematical model for their own use on the basis of its description. This is often necessary for granting licences or policy planning. Equipment, software and other requirements are not given. The description of a mathematical model should give the user a good insight into the value of the model and the results obtained. To do this the field of application and the underlying scientific concepts should be clearly described. Besides the results of possible validation procedures the way in which broader acceptance is aimed at and the degree to which this is achieved has to be reflected. (au)

  4. Impact of transpacific aerosol on air quality over the United States: A perspective from aerosol-cloud-radiation interactions

    Science.gov (United States)

    Tao, Zhining; Yu, Hongbin; Chin, Mian

    2016-01-01

    Observations have well established that aerosols from various sources in Asia, Europe, and Africa can travel across the Pacific and reach the contiguous United States (U.S.) at least on episodic bases throughout a year, with a maximum import in spring. The imported aerosol not only can serve as an additional source to regional air pollution (e.g., direct input), but also can influence regional air quality through the aerosol-cloud-radiation (ACR) interactions that change local and regional meteorology. This study assessed impacts of the transpacific aerosol on air quality, focusing on surface ozone and PM2.5, over the U.S. using the NASA Unified Weather Research Forecast model. Based on the results of 3-month (April to June of 2010) simulations, the impact of direct input (as an additional source) of transpacific aerosol caused an increase of surface PM2.5 concentration by approximately 1.5 μg m-3 over the west coast and about 0.5 μg m-3 over the east coast of the U.S. By influencing key meteorological processes through the ACR interactions, the transpacific aerosol exerted a significant effect on both surface PM2.5 (±6 μg m-3) and ozone (±12 ppbv) over the central and eastern U.S. This suggests that the transpacific transport of aerosol could either improve or deteriorate local air quality and complicate local effort toward the compliance with the U.S. National Ambient Air Quality Standards.

  5. Generation of scalable terahertz radiation from cylindrically focused laser pulses in air

    Science.gov (United States)

    Kuk, Donghoon; Yoo, Yungjun; Rosenthal, Eric; Jhajj, Nihal; Milchberg, Howard; Kim, Ki-Yong

    We have demonstrated scalable terahertz (THz) generation via cylindrical focusing of two-color laser pulses in air. In this experiment, we have used a terawatt (TW) laser system which can deliver >50 mJ, 800 nm, 50 fs pulses at a 10 Hz repetition rate. A 800 nm pulse passing through a nonlinear crystal (BBO) generates its second harmonic pulse (400 nm). Both pulses pass through a cylindrical lens and are focused together to generate a 2-dimensional plasma sheet in air. This yields two diverging THz lobes, characterized by an uncooled microbolometer. This observed radiation angle and pattern is explained by the optical-Cherenkov radiation theory. The diverging THz radiation is re-focused to yield strong THz field strengths (>20 MV/cm) at the focus. At laser energy of 40 mJ, cylindrical focusing provides THz energy of >30 microjoules, far exceeding the output produced by spherical focusing. This shows that cylindrical focusing can effectively minimize ionization-induced defocusing, previously observed in spherical focusing, and can allow scalable THz generation with relatively high laser energies (>20 mJ). Work supported by DOE, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Award No. 014216-001.

  6. Solar radiation modelling in the urban context

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, D.; Stone, A. [BDSP Partnership Limited, London (United Kingdom)

    2004-09-01

    This paper describes alternative methods for predicting surface irradiance in the urban context. In this the focus is on means of accounting for the effects of nearby obstructions on reducing direct sky radiation and on contributing reflected radiation. The first two methods involve abstracting the urban skyline into an effective canyon using isotropic and anisotropic tilted surface irradiance models. The third predicts the irradiance contribution from two hemispheres which are discretised into patches - given the radiance of the sky and dominant obstructions (if these exist) and associated view factors - so that we have a new simplified radiosity algorithm (SRA). Results from the three methods (isotropic canyon (IC), anisotropic canyon (AC) and simplified radiosity algorithm (SRA)) are compared with a 'truth model' under the following circumstances: (i) unobstructed sky, (ii) sky obstructed by black surfaces, (iii) sky obstructed by grey diffusely reflecting surfaces. Results show conclusively that the SRA offers superior accuracy at comparable speed to the canyon models. The SRA also compares well with a ray tracing program, it can handle urban scenes of arbitrary geometric complexity and is readily amenable for inclusion into standard computer programs that require surface irradiance as an input. (author)

  7. Radiation damage in graphite - A new model

    International Nuclear Information System (INIS)

    The standard model for interpretation of radiation damage of graphite invokes self-interstitials and vacancies and their aggregation to explain observed dimensional changes. Vacancies aggregate into lines which heal and contract the basal planes, interstitials aggregate into interlayer disks which expand the dimension perpendicular to the layers. Small clusters of interstitials (Cn, n = 4±2) appear which expand the interlayer distance, d002, but for an unknown reason can disappear and not evolve into disks. First principles calculations show that these aggregations are improbable at low temperatures (below 250oC) and that the observed annealing at these temperatures would be impossible. Our calculations show the inadequacies and motivate a new, robust and atomistically based model. At low temperatures, point defects are immobile, but form sturdy links between planes which cause buckling. Since the planes are effectively 'flexible but inextensible', the crystal expands perpendicular and contracts parallel to the basal planes. At higher temperatures, radiation damage causes collisions with planes, which then fold. At all stages, point defects do form, but their aggregation effects are minority effects at all but the highest temperatures. This new model has major implications for the interpretation of Wigner energy. (author)

  8. Two-dimensional analytical model of dry air thermal convection

    Science.gov (United States)

    Zakinyan, R. G.; Zakinyan, A. R.; Lukinov, A. A.

    2015-08-01

    In the present work, the steady-state stationary dry air thermal convection in a lower atmosphere has been studied theoretically. The thermal convection was considered without accounting for the Coriolis force, and with only the vertical temperature gradient. The stream function has been analytically obtained within the framework of two-dimensional thermal convection model in the Boussinesq approximation with velocity divergence taken as zero. It has been shown that the stream function is symmetrical about the horizontal and vertical. The expressions for the horizontal and vertical air velocity components have been obtained. The maximal vertical velocities level is in the center of the convective cell where the horizontal air velocity component is equal to zero. It has been shown that the air parcel's rotation period during the thermal convection is determined by the Brunt-Visl frequency. The expression for the maximal air velocity vertical component has been found. The dependence of the maximal air velocity vertical component on the overheat function at ground surface and on the atmosphere instability has been demonstrated. The expression for the pressure disturbance has been obtained. It has been demonstrated that at the points with maximal pressure disturbance the vertical velocity is equal to zero and the horizontal velocity is maximal. It has been found that the convection cell size depends on the atmosphere stability state.

  9. Registration of aerosol-borne radionuclides from distant sources in the air in the Ignalina NPP vicinity and theirs radiation doses

    International Nuclear Information System (INIS)

    Analysis of data of' radionuclide activity concentrations in the air near ore Ignalina NPP at 1997-2002 is presented. Distribution of 137Cs activity concentrations measured in 1997-1999 and 200-2002 are calculated. Five increases of the 137Cs concentration in the air were higher than changes caused by global processes. These increases of the 137Cs concentration were explained by potential distant sources of radionuclides. By using the HYSPLIT model, trajectories of air masses transport from the contaminated areas of the Chernobyl region to the Ignalina NPP region were calculated. Annual doses of ionizing radiation were estimated on basis measurements data using program INTERRAS. Annual dose of cosmogenic 7Be radiation fluctuated in the range 0,08-0,11 mSv/year. Annual dose of 137Cs radiation of late years were found in the range 0,0002-0,0005 mSv/year. Influences of radiation 137Cs transported from contaminated area Chernobyl NPP reflects in this fluctuation. Annual dose of Ignalina NPP emitted 60Co and 54Mn radiation changes in the range 0,01-0,1 ?Sv/year. (author)

  10. Linkage between an advanced air quality model and a mechanistic watershed model

    OpenAIRE

    Vijayaraghavan, K.; Herr, J.; S.-Y. Chen; Knipping, E.

    2010-01-01

    An offline linkage between two advanced multi-pollutant air quality and watershed models is presented. The models linked are (1) the Advanced Modeling System for Transport, Emissions, Reactions and Deposition of Atmospheric Matter (AMSTERDAM) (a three-dimensional Eulerian plume-in-grid model derived from the Community Multiscale Air Quality (CMAQ) model) and (2) the Watershed Analysis Risk Management Framework (WARMF). The pollutants linked include gaseous and particulate nitrogen, sulfur and...

  11. Numerical Modeling of Accuracy of Air Ion Field Measurement

    Czech Academy of Sciences Publication Activity Database

    Bartušek, Karel; Fiala, P.; Bachorec, T.; Kadlecová, E.

    Cambridge : The Electromagnetic Academy, 2007, s. 578-581. ISBN 978-1-934142-00-4. [Progress in Electromagnetics Research Symposium - PIERS 2007. Beijing (CN), 26.03.2007-20.03.2007] Institutional research plan: CEZ:AV0Z20650511 Keywords : air ion * numerical modeling Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  12. Models for the Prediction of Room Air Distribution

    DEFF Research Database (Denmark)

    Nielsen, Peter V.

    The paper describes work on simplified design methods made in connection with the International Energy Agency programme" Air Flow Pattern within Buildings" , Annex 20, subtask 1. It is shown that simplified models are able to indicate design values as the maximum velocity in the occupied zone and...

  13. Explicit validation of a surface shortwave radiation balance model over snow‐covered complex terrain

    OpenAIRE

    Helbig, N.; Löwe, H.; Mayer, B.; Lehning, M.

    2010-01-01

    A model that computes the surface radiation balance for all sky conditions in complex terrain is presented. The spatial distribution of direct and diffuse sky radiation is determined from observations of incident global radiation, air temperature, and relative humidity at a single measurement location. Incident radiation under cloudless sky is spatially derived from a parameterization of the atmospheric transmittance. Direct and diffuse sky radiation for all sky conditions are obtained by ...

  14. Air-quality investigation in the NIH (National Institutes of Health) Radiation Oncology Branch

    International Nuclear Information System (INIS)

    The Radiation Oncology Branch (ROB) is located in the Clinical Center of the National Institutes of Health (NIH). The occupants of the ROB facility have expressed dissatisfaction with the air-quality within the facility for several years. To identify the sources of the air quality problems in the ROB facility and to obtain recommendations for their solution, the Center for Building Technology at the National Institute of Standards and Technology (NIST, formerly The National Bureau of Standards) conducted an indoor-quality investigation of the ROB facility. Results revealed several deficiencies in the design and current condition of the ROB ventilation system, such as significant differences between the design airflow rates and those recommended in current standards and guidelines. The airflow measurements showed many instances in which measured airflow rates were different from their design values and revealed the existence of airflows leading to the potential for pollutant transport within the building. The contaminant measurements fell generally well below the maximum values in the ASHRAE air-quality standard. Thermal-comfort measurements revealed instances when the temperature and relative humidity were outside of ASHRAE comfort limits. Recommendations are made to remedy the deficiencies noted and to control the conditions contributing to the building's air-quality problems

  15. The influence of the solar radiation model on the calcutated solar radiation from a horizontal surface to a tilted surface

    DEFF Research Database (Denmark)

    Andersen, Elsa; Lund, Hans; Furbo, Simon

    heating systems, different solar radiation models can be used. The calculation of beam radiation from a horizontal surface to a tilted surface can be done exactly whereas different solar radiation models can calculate the sky diffuse radiation. The sky diffuse radiation can either be assumed evenly...... yearly thermal performances of a solar collector using the different solar radiation processing models is investigated. The study shows that the isotropic diffuse radiation model is underestimating the diffuse radiation from south and overestimating the diffuse radiation from north, while the anisotropic...... models give a better estimate on the diffuse radiation from all directions....

  16. InMAP: a new model for air pollution interventions

    Science.gov (United States)

    Tessum, C. W.; Hill, J. D.; Marshall, J. D.

    2015-10-01

    Mechanistic air pollution models are essential tools in air quality management. Widespread use of such models is hindered, however, by the extensive expertise or computational resources needed to run most models. Here, we present InMAP (Intervention Model for Air Pollution), which offers an alternative to comprehensive air quality models for estimating the air pollution health impacts of emission reductions and other potential interventions. InMAP estimates annual-average changes in primary and secondary fine particle (PM2.5) concentrations - the air pollution outcome generally causing the largest monetized health damages - attributable to annual changes in precursor emissions. InMAP leverages pre-processed physical and chemical information from the output of a state-of-the-science chemical transport model (WRF-Chem) within an Eulerian modeling framework, to perform simulations that are several orders of magnitude less computationally intensive than comprehensive model simulations. InMAP uses a variable resolution grid that focuses on human exposures by employing higher spatial resolution in urban areas and lower spatial resolution in rural and remote locations and in the upper atmosphere; and by directly calculating steady-state, annual average concentrations. In comparisons run here, InMAP recreates WRF-Chem predictions of changes in total PM2.5 concentrations with population-weighted mean fractional error (MFE) and bias (MFB) < 10 % and population-weighted R2 ~ 0.99. Among individual PM2.5 species, the best predictive performance is for primary PM2.5 (MFE: 16 %; MFB: 13 %) and the worst predictive performance is for particulate nitrate (MFE: 119 %; MFB: 106 %). Potential uses of InMAP include studying exposure, health, and environmental justice impacts of potential shifts in emissions for annual-average PM2.5. Features planned for future model releases include a larger spatial domain, more temporal information, and the ability to predict ground-level ozone (O3) concentrations. The InMAP model source code and input data are freely available online.

  17. A new radiation model for Baltic Sea ecosystem modelling

    Science.gov (United States)

    Neumann, Thomas; Siegel, Herbert; Gerth, Monika

    2015-12-01

    Photosynthetically available radiation (PAR) is one of the key requirements for primary production in the ocean. The ambient PAR is determined by incoming solar radiation and optical properties of sea water and the optically active water constituents along the radiation pathway. Especially in coastal waters, the optical properties are affected by terrigenous constituents like yellow substances as well as high primary production. Numerical models for marine ecosystems account for the optical attenuation process in different ways and details. For the consideration of coloured dissolved organic matter (CDOM) and shading effects of phytoplankton particles, we propose a dynamic parametrization for the Baltic Sea. Furthermore, products from biological turnover processes are implemented. Besides PAR and its attenuation coefficient, the model calculates the Secchi disk depth, a simple measurable parameter describing the transparency of the water column and a water quality parameter in the European Water Framework Directive. The components of the proposed optical model are partly implemented from other publications respectively derived from our own measurements for the area of investigation. The model allows a better representation of PAR with a more realistic spatial and temporal variability compared to former parametrizations. The effect is that regional changes of primary production, especially in the northern part of the Baltic Sea, show reduced productivity due to higher CDOM concentrations. The model estimates for Secchi disk depth are much more realistic now. In the northern Baltic Sea, simulated oxygen concentrations in deep water have improved considerably.

  18. Improved air ventilation rate estimation based on a statistical model

    International Nuclear Information System (INIS)

    A new approach to air ventilation rate estimation from CO measurement data is presented. The approach is based on a state-space dynamic statistical model, allowing for quick and efficient estimation. Underlying computations are based on Kalman filtering, whose practical software implementation is rather easy. The key property is the flexibility of the model, allowing various artificial regimens of CO level manipulation to be treated. The model is semi-parametric in nature and can efficiently handle time-varying ventilation rate. This is a major advantage, compared to some of the methods which are currently in practical use. After a formal introduction of the statistical model, its performance is demonstrated on real data from routine measurements. It is shown how the approach can be utilized in a more complex situation of major practical relevance, when time-varying air ventilation rate and radon entry rate are to be estimated simultaneously from concurrent radon and CO measurements

  19. Air quality along motorways. Measuring and modelling calculations

    International Nuclear Information System (INIS)

    This report describes the air quality along Koege Bugt motorway, one of the most trafficked sections in Denmark. A number of measurements have been carried out along Koege Bugt motorway at Greve for a three-month period in the autumn of 2003. For the first time in Denmark, NOx were measured with high time dissolution from different distances of the motorway. Furthermore, a number of meteorological parameters were measured in order to map local meteorological conditions. An air quality model describing dispersal and conversion has been made on the basis of the OML model. The OML model is modified in order to take traffic-made turbulence into consideration. The model has been evaluated through comparisons between measurements and simulated calculations. Furthermore, simulated calculations for the year 2003 has been made for comparison with extreme values. (BA)

  20. Evaluation of the quality of hot air dehydrated onion coming from gamma radiated bulbs

    International Nuclear Information System (INIS)

    The purpose of this work was to evaluate the quality of hot air dehydrated onion, as regards physical and chemical characteristics, coming from the regional product that was gamma irradiated for sprout inhibition. We worked with the onion variety Valenciana Sintetica 14. Radio inhibition was made 30 days post harvest with gamma radiation from a 60Co source at the Centro Atomico Ezeiza-CNEA, using a dose of 60 Gy. The skin of the bulbs was manually removed and the bulbs were cut in pieces 3 mm thick and between 1 and 3 cm long. The material was dehydrated in a rotating dryer with forced air circulation at 60 C degrees, between 0.8 and 1.7 m/s air speed and at ambient relative humidity. Dehydration was made 80 days after post-irradiation. The quality of the dehydrated onion was evaluated by the following physical- chemical analysis: total solids content, pungency (indirectly measured by pyruvic acid content assessment), color, pH, carbon hydrates and sensorial analysis. All analytical determinations were made in triplicate. The results obtained showed there are no significant changes between the averages of the physical-chemical properties of the control dehydrated samples and those coming from the radio-inhibited raw matter. According to the sensorial analysis, only the color of dehydrated onion was affected by the radio inhibition process. However, and according to the panel members comment, the greatest browning degree observed in ionizing radiation treated onion seemed to result more attractive to them. It may be concluded that radio inhibited regional onion can be useful as raw matter for hot air dehydrated product. It must be remarked that its use would extend the product use by dehydration plants, thus implying an increase of their processing capacity with the corresponding financial benefit. (author)

  1. A comparison between weighted sum of gray and spectral CK radiation models for heat transfer calculations in furnaces

    Energy Technology Data Exchange (ETDEWEB)

    El Ammouri, F.; Plessier, R.; Till, M.; Marie, B.; Djavdan, E. [Air Liquide Centre de Recherche Claude Delorme, 78 - Jouy-en-Josas (France)

    1996-12-31

    Coupled reactive fluid dynamics and radiation calculations are performed in air and oxy-fuel furnaces using two gas radiative property models. The first one is the weighted sum of gray gases model (WSGG) and the second one is the correlated-k (CK) method which is a spectral model based on the cumulative distribution function of the absorption coefficient inside a narrow band. The WSGG model, generally used in industrial configurations, is less time consuming than the CK model. However it is found that it over-predicts radiative fluxes by about 12 % in industrial furnaces. (authors) 27 refs.

  2. Modeling solar-driven ejector refrigeration system offering air conditioning for office buildings

    Energy Technology Data Exchange (ETDEWEB)

    Guo, J.; Shen, H.G. [School of Environmental Science and Engineering, Donghua University, 2999 North Renmin Road, Shanghai 201620 (China)

    2009-02-15

    A lumped method combined with dynamic model is proposed for use in investigating the performance and solar fraction of a solar-driven ejector refrigeration system (SERS) using R134a, for office air conditioning application for buildings in Shanghai, China. Classical hourly outdoor temperature and solar radiation model were used to provide basic data for accurate analysis of the system performance. Results indicate that during the office working-time, i.e., from 9:00 to 17:00, the average COP and the average solar fraction of the system were 0.48 and 0.82 respectively when the operating conditions were: generator temperature (85 C), evaporator temperature (8 C) and condenser temperature varying with ambient temperature. Compared with traditional compressor based air conditioner, the system can save upto 80% electric energy when providing the same cooling capacity for office buildings. Hence, the system offers a good energy conservation method for office buildings. (author)

  3. Air travel and radiation risks - review of current knowledge; Flugreisen und Strahlenrisiken - eine aktuelle Uebersicht

    Energy Technology Data Exchange (ETDEWEB)

    Zeeb, H. [Bielefeld Univ. (Germany). Fakultaet fuer Gesundheitswissenschaften; Blettner, M. [Mainz Univ. (Germany). Inst. fuer Medizinische Biometrie, Epidemiologie und Informatik

    2004-07-01

    Aircrew and passengers are exposed to cosmic radiation, in particular when travelling routes close to the poles and in high altitudes. The paper reviews current radiation measurement and estimation approaches as well as the actual level of cosmic radiation that personnel and travellers receive and summarizes the available epidemiological evidence on health effects of cosmic radiation. On average, German aircrew is exposed to les than 5 mSv per annum, and even frequent travellers only rarely reach values above 1 mSv/year. Cohort studies among aircrew have found very little evidence for an increased incidence or mortality of radiation-associated cancers. Only malignant melanoma rates have consistently found to be increased among male aircrew. Socioeconomic and reproductive aspects are likely to contribute to the slightly elevated breast cancer risk of female aircrew. Cytogenetic studies have not yielded consistent results. Based on these data overall risk increases for cancer among occupationally exposed aircrew appear unlikely. This also applies to air travellers who are usually exposed to much lower radiation levels. Occasional air travel during pregnancy does not pose a significant radiation risk, but further considerations apply in this situation. The currently available studies are limited with regard to methodological issues and case numbers so that a continuation of cohort studies in several European countries is being planned. (orig.) [German] Sowohl Flugpersonal wie Flugreisende sind kosmischer Strahlung ausgesetzt, insbesondere wenn sie auf polnahen Routen und in grossen Flughoehen reisen. Die vorliegende Arbeit gibt einen aktuellen Ueberblick ueber Mess- und Schaetzverfahren sowie das Ausmass der kosmischen Strahlenexposition und fasst die derzeit bekannte epidemiologische Evidenz zu gesundheitlichen Aspekten der kosmischen Strahlenexposition zusammen. Die durchschnittliche jaehrliche Strahlenexposition beruflich exponierten Flugpersonals liegt in Deutschland unter 5 mSv, selbst regelmaessig Flugreisende erreichen nur selten Werte ueber 1 mSv. In Kohortenstudien bei Flugpersonal wurden kaum Hinweise auf erhoehte Inzidenz oder Mortalitaet strahlenassoziierter Tumore gefunden, konsistente Risikoerhoehungen wurden jedoch fuer das maligne Melanom bei Maennern berichtet. Ursachen fuer die leicht erhoehte Brustkrebsinzidenz des Flugpersonals werden auch in reproduktiven und soziooekonomischen Faktoren gesehen. Zytogenetische Untersuchungen auf strahlenassoziierte Veraenderungen ergeben bisher kein konsistentes Bild. Aufgrund der derzeit vorliegenden Ergebnisse ist das zusaetzliche Krebsrisiko fuer beruflich strahlenexponiertes Flugpersonal nicht deutlich erhoeht. Fuer Flugreisende ist aufgrund der niedrigeren Exposition eine Risikoerhoehung ebenfalls weitgehend auszuschliessen. Gelegentliche Flugreisen in der Schwangerschaft werden vor dem Hintergrund der epidemiologischen Daten ebenfalls als unbedenklich eingeschaetzt, aber hier spielen weitere Erwaegungen eine Rolle. Die bisher vorliegenden Studien weisen Einschraenkungen in Bezug auf methodische Vorgehensweisen und Fallzahlen auf, so dass in mehreren europaeischen Laendern eine Fortsetzung der Kohortenstudien bei Flugpersonal geplant sind. (orig.)

  4. The status and quality of radiation measurements for air. Interim report 1973--1975

    International Nuclear Information System (INIS)

    As part of the radiation quality assurance program conducted by the U.S. Environmental Protection Agency, calibrated radionuclide solutions are distributed to participating laboratories for instrument calibration and yield determinations. Laboratory performance studies involving the analysis of radionuclides in environmental media are also conducted. A summary is given of the results of the air filter cross-check program for 1973-1975. Examination of these results indicate that gross alpha is the least difficult (86 percent within the control limits for accuracy) and gross beta is the most difficult (39 percent within the control limits for accuracy) for the laboratories to analyze

  5. Air filled ionization chambers and their response to high LET radiation

    DEFF Research Database (Denmark)

    Kaiser, Franz-Joachim; Bassler, Niels; Tölli, Heikki; Jäkel, Oliver

    Background Air filled ionization chambers (ICs) are widely used for absolute dosimetry, not only in photon beams but also in beams of heavy charged particles. Within the IC, electron hole pairs are generated by the energy deposition originating from incoming radiation. High-LET particles create a...... high density of charge carriers in the core of particle tracks. As a consequence an increased (so called "initial") recombination of the charge carriers takes place, besides of the general (volume) recombination described by the Boag theory. A theory for a sub-type of initial recombination ("columnar...

  6. "Developing a multi hazard air quality forecasting model for Santiago, Chile"

    Science.gov (United States)

    Mena, M. A.; Delgado, R.; Hernandez, R.; Saide, P. E.; Cienfuegos, R.; Pinochet, J. I.; Molina, L. T.; Carmichael, G. R.

    2013-05-01

    Santiago, Chile has reduced annual particulate matter from 69ug/m3 (in 1989) to 25ug/m3 (in 2012), mostly by forcing industry, the transport sector, and the residential heating sector to adopt stringent emission standards to be able to operate under bad air days. Statistical forecasting has been used to predict bad air days, and pollution control measures in Santiago, Chile, for almost two decades. Recently an operational PM2.5 deterministic model has been implemented using WRF-Chem. The model was developed by the University of Iowa and is run at the Chilean Meteorological Office. Model configuration includes high resolution emissions gridding (2km) and updated population distribution using 2008 data from LANDSCAN. The model is run using a 2 day spinup with a 5 day forecast. This model has allowed a preventive approach in pollution control measures, as episodes are the results of multiple days of bad dispersion. Decreeing air pollution control measures in advance of bad air days resulted in a reduction of 40% of alert days (80ug/m3 mean 24h PM2.5) and 66% of "preemergency days" (110ug/m3 mean 24h PM2.5) from 2011 to 2012, despite similar meteorological conditions. This model will be deployed under a recently funded Center for Natural Disaster Management, and include other meteorological hazards such as flooding, high temperature, storm waves, landslides, UV radiation, among other parameters. This paper will present the results of operational air quality forecasting, and the methodology that will be used to transform WRF-Chem into a multi hazard forecasting system.

  7. Spatial distribution of emissions to air - the SPREAD model

    Energy Technology Data Exchange (ETDEWEB)

    Plejdrup, M.S.; Gyldenkaerne, S.

    2011-04-15

    The National Environmental Research Institute (NERI), Aarhus University, completes the annual national emission inventories for greenhouse gases and air pollutants according to Denmark's obligations under international conventions, e.g. the climate convention, UNFCCC and the convention on long-range transboundary air pollution, CLRTAP. NERI has developed a model to distribute emissions from the national emission inventories on a 1x1 km grid covering the Danish land and sea territory. The new spatial high resolution distribution model for emissions to air (SPREAD) has been developed according to the requirements for reporting of gridded emissions to CLRTAP. Spatial emission data is e.g. used as input for air quality modelling, which again serves as input for assessment and evaluation of health effects. For these purposes distributions with higher spatial resolution have been requested. Previously, a distribution on the 17x17 km EMEP grid has been set up and used in research projects combined with detailed distributions for a few sectors or sub-sectors e.g. a distribution for emissions from road traffic on 1x1 km resolution. SPREAD is developed to generate improved spatial emission data for e.g. air quality modelling in exposure studies. SPREAD includes emission distributions for each sector in the Danish inventory system; stationary combustion, mobile sources, fugitive emissions from fuels, industrial processes, solvents and other product use, agriculture and waste. This model enables generation of distributions for single sectors and for a number of sub-sectors and single sources as well. This report documents the methodologies in this first version of SPREAD and presents selected results. Further, a number of potential improvements for later versions of SPREAD are addressed and discussed. (Author)

  8. Modelling air quality in street canyons : a review

    OpenAIRE

    Vardoulakis, Sotiris; Fisher, Bernard E.A.; Pericleous, Koulis; Gonzalez-Flesca, Norbert

    2003-01-01

    High pollution levels have been often observed in urban street canyons due to the increased traffic emissions and reduced natural ventilation. Microscale dispersion models with different levels of complexity may be used to assess urban air quality and support decision-making for pollution control strategies and traffic planning. Mathematical models calculate pollutant concentrations by solving either analytically a simplified set of parametric equations or numerically a set of differential eq...

  9. Modelling Domestic Air Transport Demand and Evaluating under Scenarios

    OpenAIRE

    Cenk Ozan; Özgür Başkan; Soner Haldenbilen; Halim Ceylan

    2014-01-01

    The lack of balance and integration between transportation modes in Turkey is one of the main problems. In this study, domestic air transport demand is modeled and evaluated under scenarios. For this purpose, indexing method which is able to indicate observed monthly and seasonal variations in demand is used. Proposals are suggested in order to overcome the lack of balance between transportation modes. In modeling, purchasing power parity and jet fuel prices as independent variables are used....

  10. Radiation exposure of workers assigned to the maintenance of air surveillance radar

    International Nuclear Information System (INIS)

    The French Defence Radiation Protection Service (SPRA) conducted a study to assess the radiation exposure of personnel assigned to the maintenance of the Palmier radar in an Air Force Base. The aim of the study was the assessment of the annual effective doses received by personnel assigned to these maintenance operations, and the measurement of equivalent dose rates in the area in order to realize radiological zoning. In two measurement campaigns, the annual individual effective doses, measured by passive whole-body OSL InlightR dosimeters, consolidated the results obtained by radiometric measurements. Moreover, the equivalent dose rate shows wide variations in relation to the position of the operator in the emitter's area. From these results, the authors propose recommendations for categorization of workers, radiological zoning and dose monitoring procedures. (authors)

  11. Stomatal resistance of rice leaves as influenced by radiation intensity and air humidity

    International Nuclear Information System (INIS)

    This paper describes results of field experiments of relationships between meteorological conditions and stomatal resistance of rice leaves. The magnitude of stomatal resistance of rice leaves was measured by a porometer at important three developmental stages of rice plants. Stomatal resistance (rs) changed very clearly throughout sunny days in relation to diurnal variation in solar radiation intensity (St) and leaf air vapor concentration deficit (HD). Stomatal resistance of the adaxial surface of rice leaves was found to be the same to that of the abaxial surface in the magnitude, indicating that the water vapor fluxes at the both surfaces of rice leaves are equal with each other. The dependence of non-dimensional stomatal resistance [rs/rm·k(HD)2] on solar radiation intensity (St) was well approximated by a hyperbolic function. The relationship between HD and [rs/rm(1+St, m/St)] was expressed by a quadratic function of HD

  12. Modeling of air pollution from the power plant ash dumps

    Science.gov (United States)

    Aleksic, Nenad M.; Bala?, Nedeljko

    A simple model of air pollution from power plant ash dumps is presented, with emission rates calculated from the Bagnold formula and transport simulated by the ATDL type model. Moisture effects are accounted for by assumption that there is no pollution on rain days. Annual mean daily sedimentation rates, calculated for the area around the 'Nikola Tesla' power plants near Belgrade for 1987, show reasonably good agreement with observations.

  13. Study of filamentation dynamics of ultrashort laser radiation in air: beam diameter effect

    Science.gov (United States)

    Afonasenko, A. V.; Apeksimov, D. V.; Geints, Y. E.; Golik, S. S.; Kabanov, A. M.; Zemlyanov, A. A.

    2014-10-01

    A single filamentation of femtosecond gigawatt laser radiation with a millimeter-size aperture upon collimated and sharply focused propagation in atmospheric air at 800 nm and 400 nm wavelengths is studied both theoretically and experimentally. The influence of beam initial radius on the parameters of the forming filament is analyzed. Three filament parameters, namely, start coordinate, filament length, and longitudinal continuity are considered. We report that unlike Marburgers formula the single filamentation onset reveals marked nonquadratic dependence on the laser beam radius providing the same initial pulse power. Additionally, for sharply focused radiation the minor dependence of the filament length on the laser beam diameter at the constant initial pulse intensity was experimentally revealed.

  14. Study of filamentation dynamics of ultrashort laser radiation in air: beam diameter effect

    International Nuclear Information System (INIS)

    A single filamentation of femtosecond gigawatt laser radiation with a millimeter-size aperture upon collimated and sharply focused propagation in atmospheric air at 800 nm and 400 nm wavelengths is studied both theoretically and experimentally. The influence of beam initial radius on the parameters of the forming filament is analyzed. Three filament parameters, namely, start coordinate, filament length, and longitudinal continuity are considered. We report that unlike Marburger’s formula the single filamentation onset reveals marked nonquadratic dependence on the laser beam radius providing the same initial pulse power. Additionally, for sharply focused radiation the minor dependence of the filament length on the laser beam diameter at the constant initial pulse intensity was experimentally revealed. (paper)

  15. Performance of Air Pollution Models on Massively Parallel Computers

    DEFF Research Database (Denmark)

    Brown, John; Hansen, Per Christian; Wasniewski, Jerzy; Zlatev, Zahari

    1996-01-01

    To compare the performance and use of three massively parallel SIMD computers, we implemented a large air pollution model on the computers. Using a realistic large-scale model, we gain detailed insight about the performance of the three computers when used to solve large-scale scientific problems...... that involve several types of numerical computations. The computers considered in our study are the Connection Machines CM-200 and CM-5, and the MasPar MP-2216...

  16. Realistic model for radiation-matter interaction

    CERN Document Server

    Pakula, R A

    2004-01-01

    This paper presents a realistic model that describes radiation-matter interactions. This is achieved by a generalization of first quantization, where the Maxwell equations are interpreted as the electromagnetic component of the Schrodinger equation. This picture is complemented by the consideration of electrons and photons as real particles in three-dimensional space, following guiding conditions derived from the particle-wave-functions to which they are associated. The guiding condition for the electron is taken from Bohmian mechanics, while the photon velocity is defined as the ratio between the Poynting vector and the electromagnetic energy density. The case of many particles is considered, taking into account their statistical properties. The formalism is applied to a two level system, providing an intuitive description for spontaneous emission, Lamb shift, scattering, absorption, dispersion, resonance fluorescence and vacuum fields. This model describes quantum jumps by the entanglement between the photo...

  17. Plutonium air transportable package Model PAT-1. Safety analysis report

    International Nuclear Information System (INIS)

    The document is a Safety Analysis Report for the Plutonium Air Transportable Package, Model PAT-1, which was developed by Sandia Laboratories under contract to the Nuclear Regulatory Commission (NRC). The document describes the engineering tests and evaluations that the NRC staff used as a basis to determine that the package design meets the requirements specified in the NRC ''Qualification Criteria to Certify a Package for Air Transport of Plutonium'' (NUREG-0360). By virtue of its ability to meet the NRC Qualification Criteria, the package design is capable of safely withstanding severe aircraft accidents. The document also includes engineering drawings and specifications for the package. 92 figs, 29 tables

  18. Correlation of growth with solar radiation and air temperature on potted miniature rose

    International Nuclear Information System (INIS)

    To establish systematic year-round production of potted miniature rose, rose growth and environmental factors such as solar radiation and air temperature were investigated for one year and the relationships of growth to these factors were analyzed. The period from the start to end of cultivation was longer in order of summer, spring and autumn cultivation. Leaf area, fresh weight of leaf and plant, leaf number and plant height as response variables were analyzed to explain the relation to environmental factors as explanatory variables using multiple linear regression analysis. The cumulative daily mean solar radiation, cumulative daytime and nighttime temperature within explanatory variables were significant main explanatory variables. Rose growth factors; leaf area, fresh weight of leaf and plant, leaf number and plant height showed close correlation with three environmental factors, respectively. Rose growth factors demonstrated significant multiple linear regressions using three environmental factors, and the parameters in multiple linear regression equations were also significant. Therefore, we demonstrated that the rose growth could be predicted using cumulative daily mean solar radiation, cumulative daytime and nighttime temperature and could be controlled by changing solar radiation and temperature

  19. Galactic cosmic radiation exposure and associated health risks for air carrier crewmembers

    International Nuclear Information System (INIS)

    The dose equivalent to air carrier crewmembers from galactic cosmic radiation was estimated for each of 32 nonstop flights on a variety of routes to and from, or within, the contiguous United States. Flying times were from 0.4 to 13 hours. The annual dose equivalents received on the flights ranged from 0.2 to 9.1 mSv (20 to 910 mrem), or 0.4 to 18% of the recommended annual limit for occupational exposure of an adult. We reviewed some of the characteristics of galactic and solar cosmic radiation and provided example calculations for estimating radiation-induced risks of fatal cancer, genetic defects and harm to an embryo or fetus. The estimated increased risk of dying from cancer because of galactic radiation exposure received during 20 years of flying ranged from 0.1 to 5 in 1,000. For the adult U.S. population the risk of dying from cancer is about 220 in 1,000

  20. Modelling Domestic Air Transport Demand and Evaluating under Scenarios

    Directory of Open Access Journals (Sweden)

    Cenk Ozan

    2014-09-01

    Full Text Available The lack of balance and integration between transportation modes in Turkey is one of the main problems. In this study, domestic air transport demand is modeled and evaluated under scenarios. For this purpose, indexing method which is able to indicate observed monthly and seasonal variations in demand is used. Proposals are suggested in order to overcome the lack of balance between transportation modes. In modeling, purchasing power parity and jet fuel prices as independent variables are used. Results showed that the developed model using indexing method is substantially sensitive to observed monthly and seasonal variations in domestic air transport demand. Furthermore, in the event that there are optimistic an increase in the income level and a crawl in the jet fuel prices, domestic air transport can rival with railways for second place in the transportation modes behind highways. For this reason, it is considered regulation on wages policy and tax of jet fuel prices necessary to support development of domestic air transport demand.

  1. Evaluation of indoor air quality in a department of radiation oncology located underground

    International Nuclear Information System (INIS)

    Indoor air quality (IAQ) in the radiation treatment center which is generally located underground is important to the health of hospital workers and patients treated over a long period of time. This study was conducted to measure and analyze the factors related to IAQ and subjective symptoms of sick building syndrome, and to establish the causes influencing IAQ and find a solution to the problems. Self administrated questionnaire was conducted to check the workers' symptoms and understanding of the work environment. Based on a preliminary investigation, the factors related to IAQ such as temperature, humidity, fine particulate, carbon dioxide, carbon monoxide, formaldehyde, total volatile organic compounds (TVOC), and radon gas were selected and measured for a certain period of time in specific sites where hospital workers stay long in a day. And we also evaluated the surrounding environment and the efficiency of the ventilating system simultaneously, and measured the same factors at the first floor (outdoor) to compare with outdoor air quality. All collected data were assessed by the recommended standard for IAQ of the domestic and international environmental organizations. Hospital workers were discontented with foul odors, humidity and particulate. They complained symptoms related to musculo-skeletal system, neurologic system, and mucosal-irritation. Most of the factors were not greater than the recommended standard, but the level of TVOC was third or fourth times as much as the measuring level of some offices in the United States. The frequency and the amount of the ventilating system were adequate, however, the problem arising in the position of outdoor-air inlets and indoor-air outlets involved a risk of the indraft of contaminated air. A careful attention was a requirement in handling and keeping chemical substances including a developing solution which has a risk of TVOC emissions, and repositioning the ventilating system was needed to solve the contaminated-air circulation immediately. We verified that some IAQ-related factors and inadequate ventilating system could cause subjective symptoms in hospital workers. The evaluation of IAQ was surely needed to improve the underground working environment for hospital workers and patients. On the basis of these data, from now on, we should actively engage in designs of the department of radiation oncology or improvement in environment of the existing facilities

  2. Indicators to support the dynamic evaluation of air quality models

    Science.gov (United States)

    Thunis, P.; Clappier, A.

    2014-12-01

    Air quality models are useful tools for the assessment and forecast of pollutant concentrations in the atmosphere. Most of the evaluation process relies on the operational phase or in other words the comparison of model results with available measurements which provides insight on the model capability to reproduce measured concentrations for a given application. But one of the key advantages of air quality models lies in their ability to assess the impact of precursor emission reductions on air quality levels. Models are then used in a dynamic mode (i.e. response to a change in a given model input data) for which evaluation of the model performances becomes a challenge. The objective of this work is to propose common indicators and diagrams to facilitate the understanding of model responses to emission changes when models are to be used for policy support. These indicators are shown to be useful to retrieve information on the magnitude of the locally produced impacts of emission reductions on concentrations with respect to the external to the domain contribution but also to identify, distinguish and quantify impacts arising from different factors (different precursors). In addition information about the robustness of the model results is provided. As such these indicators might reveal useful as first screening methodology to identify the feasibility of a given action as well as to prioritize the factors on which to act for an increased efficiency. Finally all indicators are made dimensionless to facilitate the comparison of results obtained with different models, different resolutions, or on different geographical areas.

  3. Testing theoretical models of magnetic damping using an air track

    CERN Document Server

    Vidaurre, A; Monsoriu, J A; Riera, J; Gimenez, Marcos H.; Monsoriu, Juan A.; Riera, Jaime; Vidaurre, Ana

    2007-01-01

    Magnetic braking is a long-established application of Lenz's law. A rigorous analysis of the laws governing this problem involves solving Maxwell's equations in a time-dependent situation. Approximate models have been developed to describe different experiences related to this phenomenon. In this paper we present a new method for the analysis of the magnetic braking using a magnet fixed to the glider of an air track. The forces acting on the glider, a result of the eddy currents, can be easily observed and measured. As a consequence of the air track inclination, the glider accelerates at the beginning, although it asymptotically tends towards a uniform rectilinear movement characterized by a terminal speed. This speed depends on the interaction between the magnetic field and the conductivity properties of the air track. Compared with previous related approaches, in our experimental setup the magnet fixed to the glider produces a magnetic braking force which acts continuously, rather than over a short period o...

  4. Air Pollution Radiative Forcing From Specific Emissions Sectors at 2030: Prototype for a New IPCC Bar Chart

    Science.gov (United States)

    Unger, N.; Shindell, D. T.; Koch, D. M.

    2007-05-01

    Reduction of short-lived air pollutants provides a way to mitigate global warming in the short-term with ancillary benefits to human health. However, the radiative forcings of short-lived air pollutants depend on the location and source type of the precursor emissions. We apply the GISS atmospheric composition-climate model to quantify near future (2030 A1B) ozone (O3) and sulfate global mean direct radiative forcing impacts from 6 emissions sectors from 7 geographic regions. At 2030 the net forcings for the emissions sectors (including O3, sulfate, black and organic carbon forcings) are (in mW/m2): transportation = +106; biomass burning = +69; domestic = +38; power = -158; industry = -124. Hence the transportation sector is the most attractive target to counter global warming via reduction of short-lived air pollutants. Substantial transportation sector O3 forcings come from all regions (5-12 mW/m2). Central and Southern Africa and South America contribute the largest biomass burning O3 forcings (11-15 mW/m2). Domestic biofuel emissions from East Asia, South Asia and Central and South Africa and power and industry emissions from East Asia also contribute substantial O3 forcings (7-15mW/m2). The global mean sulfate forcings are dominated by the power and industry sectors with largest contributions from East Asia, South Asia and North Africa and Middle East (-30 to -50 mW/m2). Linear relationships exist between global mean radiative forcing by O3 and biomass burning and domestic biofuel CO precursor emissions independent of the region of origin with sensitivity of 0.02mW/m2/TgCO. Similarly, linear relationships are available for global mean radiative forcing by sulfate and SO2 precursor emissions that depend upon region but are independent of the emissions sector with sensitivities ranging from -3 to -12mW/m2/TgS. Such emissions to forcing diagnostics will assist development of climate-motivated policy for O3 and sulfate.

  5. Development of a distributed air pollutant dry deposition modeling framework

    International Nuclear Information System (INIS)

    A distributed air pollutant dry deposition modeling system was developed with a geographic information system (GIS) to enhance the functionality of i-Tree Eco (i-Tree, 2011). With the developed system, temperature, leaf area index (LAI) and air pollutant concentration in a spatially distributed form can be estimated, and based on these and other input variables, dry deposition of carbon monoxide (CO), nitrogen dioxide (NO2), sulfur dioxide (SO2), and particulate matter less than 10 microns (PM10) to trees can be spatially quantified. Employing nationally available road network, traffic volume, air pollutant emission/measurement and meteorological data, the developed system provides a framework for the U.S. city managers to identify spatial patterns of urban forest and locate potential areas for future urban forest planting and protection to improve air quality. To exhibit the usability of the framework, a case study was performed for July and August of 2005 in Baltimore, MD. - Highlights: ► A distributed air pollutant dry deposition modeling system was developed. ► The developed system enhances the functionality of i-Tree Eco. ► The developed system employs nationally available input datasets. ► The developed system is transferable to any U.S. city. ► Future planting and protection spots were visually identified in a case study. - Employing nationally available datasets and a GIS, this study will provide urban forest managers in U.S. cities a framework to quantify and visualize urban forest structure and its air pollution removal effect.

  6. Effect mechanism of air deflectors on the cooling performance of dry cooling tower with vertical delta radiators under crosswind

    International Nuclear Information System (INIS)

    Highlights: • A 3D numerical model was set for NDDCTV to study the effect of air deflectors. • The air deflectors improve the tower performance by 1.375 °C at uc = 6 m/s for a case. • The air deflectors reduce the air inflow deviation angle θd at most delta entries. • The reduced θd can improve the cooling performance of former deteriorated columns. • Both the radial inflow air velocity and θd impact the cooling performance of delta. - Abstract: To study the effect mechanism of air deflectors on dry cooling tower, a three dimensional numerical model was established, with full consideration of the delta structure. The accuracy and credibility of dry cooling tower numerical model were validated. By numerical model, the average air static pressure and the average radial inflow air velocity were computed and analyzed at delta air entry, sector air entry and exit faces. By the air inflow deviation angle θd, the effect of air deflectors on the aerodynamic field around tower was analyzed. The water exit temperatures of θ−1 columns, θ+2 columns and cooling sectors were also presented to clarify the effect of air deflectors. It was found that the air deflectors improved the aerodynamic field around cooling columns. The reduced air inflow deviation degree at delta entry improved the cooling performance of deteriorated columns. Referring to the radial inflow air velocity ura and the air inflow deviation degree at delta entry, the effect mechanism of air deflectors are clarified under crosswind

  7. Air quality and radiative impacts of Arctic shipping emissions in the summertime in northern Norway: from the local to the regional scale

    OpenAIRE

    Marelle, Louis; Thomas, Jennie L.; Raut, Jean-Christophe; Law, Kathy S.; Jalkanen, Jukka-Pekka; Johansson, Lasse; Roiger, Anke; Schlager, Hans; Kim, Jin; Reiter, Anja; Weinzierl, Bernadett

    2016-01-01

    In this study, we quantify the impacts of shipping pollution on air quality and shortwave radiative effect in northern Norway, using WRF-Chem (Weather Research and Forecasting with chemistry) simulations combined with high-resolution, real-time STEAM2 (Ship Traffic Emissions Assessment Model version 2) shipping emissions. STEAM2 emissions are evaluated using airborne measurements from the ACCESS (Arctic Climate Change, Economy and Society) aircraft campaign, which was conducted i...

  8. Impacts of contaminant storage on indoor air quality: Model development

    Science.gov (United States)

    Sherman, Max H.; Hult, Erin L.

    2013-06-01

    A first-order, lumped capacitance model is used to describe the buffering of airborne chemical species by building materials and furnishings in the indoor environment. The model is applied to describe the interaction between formaldehyde in building materials and the concentration of the species in the indoor air. Storage buffering can decrease the effect of ventilation on the indoor concentration, compared to the inverse dependence of indoor concentration on the air exchange rate that is consistent with a constant emission rate source. If the exposure time of an occupant is long relative to the timescale of depletion of the compound from the storage medium, however, the total exposure will depend inversely on the air exchange rate. This lumped capacitance model is also applied to moisture buffering in the indoor environment, which occurs over much shorter depletion timescales of the order of days. This model provides a framework to interpret the impact of storage buffering on time-varying concentrations of chemical species and resulting occupant exposure. Pseudo-steady-state behavior is validated using field measurements. Model behavior over longer times is consistent with formaldehyde and moisture concentration measurements in previous studies.

  9. Modeling of air toxics from hydrocarbon pool fires

    International Nuclear Information System (INIS)

    While there is guidance for estimating the radiation hazards of fires (ARCHIE), there is little guidance on modeling the dispersion of hazardous materials from fires. The objective of this paper is to provide a review of the methodology used for modeling the impacts of liquid hydrocarbon pool fires. The required input variables for modeling of hydrocarbon pool fires include emission strength, emission duration, and dispersion characteristics. Methods for predicting the products of combustion including the use of literature values, test data, and thermodynamic equilibrium calculations are discussed. The use of energy balances coupled to radiative heat transfer calculations are presented as a method for determining flame temperature. Fire modeling literature is reviewed in order to determine other source release variables such as mass burn rate and duration and flame geometry

  10. Flavour Dependent Gauged Radiative Neutrino Mass Model

    CERN Document Server

    Baek, Seungwon; Yagyu, Kei

    2015-01-01

    We propose a one-loop induced radiative neutrino mass model with anomaly free flavour dependent gauge symmetry: $\\mu$ minus $\\tau$ symmetry $U(1)_{\\mu-\\tau}$. A neutrino mass matrix satisfying current experimental data can be obtained by introducing a weak isospin singlet scalar boson that breaks $U(1)_{\\mu-\\tau}$ symmetry, an inert doublet scalar field, and three right-handed neutrinos in addition to the fields in the standard model. We find that a characteristic structure appears in the neutrino mass matrix: two-zero texture form which predicts three non-zero neutrino masses and three non-zero CP-phases which can be determined five well measured experimental inputs of two squared mass differences and three mixing angles. Furthermore, it is clarified that only the inverted mass hierarchy is allowed in our model. In a favored parameter set from the neutrino sector, the discrepancy in the muon anomalous magnetic moment between the experimental data and the the standard model prediction can be explained by the ...

  11. Quality assurance for radon exposure chambers at the National Air and Radiation Environmental Laboratory, Montgomery, Alabama

    Energy Technology Data Exchange (ETDEWEB)

    Semler, M.O.; Sensintaffar, E.L. [National Air and Radiation Environmental Laboratory, Montgomery, AL (United States)

    1993-12-31

    The Office of Radiation and Indoor Air, U.S. Environmental Protection Agency (EPA), operates six radon exposure chambers in its two laboratories, the National Air and Radiation Environmental Laboratory (NAREL) in Montgomery, Alabama, and the Las Vegas Facility, Las Vegas, Nevada. These radon exposure chambers are used to calibrate and test portable radon measuring instruments, test commercial suppliers of radon measurement services through the Radon Measurement Proficiency Program, and expose passive measurement devices to known radon concentrations as part of a quality assurance plan for federal and state studies measuring indoor radon concentrations. Both laboratories participate in national and international intercomparisons for the measurement of radon and are presently working with the National Institute of Standards and Technology (NIST) to receive a certificate of traceability for radon measurements. NAREL has developed an estimate of the total error in its calibration of each chamber`s continuous monitors as part of an internal quality assurance program. This paper discusses the continuous monitors and their calibration for the three chambers located in Montgomery, Alabama, as well as the results of the authors intercomparisons and total error analysis.

  12. Ultraviolet radiation therapy and UVR dose models

    Energy Technology Data Exchange (ETDEWEB)

    Grimes, David Robert, E-mail: davidrobert.grimes@oncology.ox.ac.uk [School of Physical Sciences, Dublin City University, Glasnevin, Dublin 9, Ireland and Cancer Research UK/MRC Oxford Institute for Radiation Oncology, Gray Laboratory, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ (United Kingdom)

    2015-01-15

    Ultraviolet radiation (UVR) has been an effective treatment for a number of chronic skin disorders, and its ability to alleviate these conditions has been well documented. Although nonionizing, exposure to ultraviolet (UV) radiation is still damaging to deoxyribonucleic acid integrity, and has a number of unpleasant side effects ranging from erythema (sunburn) to carcinogenesis. As the conditions treated with this therapy tend to be chronic, exposures are repeated and can be high, increasing the lifetime probability of an adverse event or mutagenic effect. Despite the potential detrimental effects, quantitative ultraviolet dosimetry for phototherapy is an underdeveloped area and better dosimetry would allow clinicians to maximize biological effect whilst minimizing the repercussions of overexposure. This review gives a history and insight into the current state of UVR phototherapy, including an overview of biological effects of UVR, a discussion of UVR production, illness treated by this modality, cabin design and the clinical implementation of phototherapy, as well as clinical dose estimation techniques. Several dose models for ultraviolet phototherapy are also examined, and the need for an accurate computational dose estimation method in ultraviolet phototherapy is discussed.

  13. Aviation System Analysis Capability Air Carrier Investment Model-Cargo

    Science.gov (United States)

    Johnson, Jesse; Santmire, Tara

    1999-01-01

    The purpose of the Aviation System Analysis Capability (ASAC) Air Cargo Investment Model-Cargo (ACIMC), is to examine the economic effects of technology investment on the air cargo market, particularly the market for new cargo aircraft. To do so, we have built an econometrically based model designed to operate like the ACIM. Two main drivers account for virtually all of the demand: the growth rate of the Gross Domestic Product (GDP) and changes in the fare yield (which is a proxy of the price charged or fare). These differences arise from a combination of the nature of air cargo demand and the peculiarities of the air cargo market. The net effect of these two factors are that sales of new cargo aircraft are much less sensitive to either increases in GDP or changes in the costs of labor, capital, fuel, materials, and energy associated with the production of new cargo aircraft than the sales of new passenger aircraft. This in conjunction with the relatively small size of the cargo aircraft market means technology improvements to the cargo aircraft will do relatively very little to spur increased sales of new cargo aircraft.

  14. CLOUDS, AEROSOLS, RADIATION AND THE AIR-SEA INTERFACE OF THE SOUTHERN OCEAN: ESTABLISHING DIRECTIONS FOR FUTURE RESEARCH

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Robert [University of Washington; Bretherton, Chris [University of Washington; McFarquhar, Greg [University of Illinois - Urbana; Protat, Alain [Bureau of Meteorology - Melbourne; Quinn, Patricia [NOAA PMEL; Siems, Steven [Monash Univ., Melbourne, VIC (Australia); Jakob, Christian [Monash Univ., Melbourne, VIC (Australia); Alexander, Simon [Australian Antarctic Division; Weller, Bob [Woods Hole Oceanographic Institute

    2014-09-29

    A workshop sponsored by the Department of Energy was convened at the University of Washington to discuss the state of knowledge of clouds, aerosols and air-sea interaction over the Southern Ocean and to identify strategies for reducing uncertainties in their representation in global and regional models. The Southern Ocean plays a critical role in the global climate system and is a unique pristine environment, yet other than from satellite, there have been sparse observations of clouds, aerosols, radiation and the air-sea interface in this region. Consequently, much is unknown about atmospheric and oceanographic processes and their linkage in this region. Approximately 60 scientists, including graduate students, postdoctoral fellows and senior researchers working in atmospheric and oceanic sciences at U.S. and foreign universities and government laboratories, attended the Southern Ocean Workshop. It began with a day of scientific talks, partly in plenary and partly in two parallel sessions, discussing the current state of the science for clouds, aerosols and air-sea interaction in the Southern Ocean. After the talks, attendees broke into two working groups; one focused on clouds and meteorology, and one focused on aerosols and their interactions with clouds. This was followed by more plenary discussion to synthesize the two working group discussions and to consider possible plans for organized activities to study clouds, aerosols and the air-sea interface in the Southern Ocean. The agenda and talk slides, including short summaries of the highlights of the parallel session talks developed by the session chars, are available at http://www.atmos.washington.edu/socrates/presentations/SouthernOceanPresentations/.

  15. Monitoring of radiation fields in a waste tank model: Virtual radiation dosimetry

    International Nuclear Information System (INIS)

    The University of Florida (UF) has developed a coupled radiation computation and three-dimensional modeling simulation code package. This package combines the Deneb Robotics' IGRIP three-dimensional solid modeling robotic simulation code with the UF developed VRF (Virtual Radiation Field) Monte Carlo based radiation computation code. The code package allows simulated radiation dose monitors to be placed anywhere on simulated robotic equipment to record the radiation doses which would be sustained when carrying out tasks in radiation environments. Comparison with measured values in the Hanford Waste Tank C-106 shows excellent results. The code shows promise of serving as a major tool in the design and operation of robotic equipment in radiation environments to ensure freedom from radiation caused failure

  16. Angular radiation models for earth-atmosphere system. Volume 2: Longwave radiation

    Science.gov (United States)

    Suttles, J. T.; Green, R. N.; Smith, G. L.; Wielicki, B. A.; Walker, I. J.; Taylor, V. R.; Stowe, L. L.

    1989-01-01

    The longwave angular radiation models that are required for analysis of satellite measurements of Earth radiation, such as those from the Earth Radiation Budget Experiment (ERBE) are presented. The models contain limb-darkening characteristics and mean fluxes. Limb-darkening characteristics are the longwave anisotropic factor and the standard deviation of the longwave radiance. Derivation of these models from the Nimbus 7 ERB (Earth Radiation Budget) data set is described. Tabulated values and computer-generated plots are included for the limb-darkening and mean-flux models.

  17. Development of a hydrodynamic model for air-lift reactors

    Directory of Open Access Journals (Sweden)

    Carvalho E.

    2000-01-01

    Full Text Available In this paper, a 1D hydrodynamic model has been developed for gas hold-up and liquid circulation velocity prediction in air-lift reactors. The model is based on momentum balance equations and has been adjusted to experimental data collected on a pilot plant reactor equipped with two types of gas distributors and using water and water/butanol as the liquid phase. Different techniques of signal analysis have also been applied to pressure fluctuations in order to extract information about flow regimes and regime transitions. A good knowledge of the flow pattern is essential to establish adequate correlations for the hydrodynamic model.

  18. Development of a forecast model for global air traffic emissions

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, Martin

    2012-07-01

    The thesis describes the methodology and results of a simulation model that quantifies fuel consumption and emissions of civil air traffic. Besides covering historical emissions, the model aims at forecasting emissions in the medium-term future. For this purpose, simulation models of aircraft and engine types are used in combination with a database of global flight movements and assumptions about traffic growth, fleet rollover and operational aspects. Results from an application of the model include emissions of scheduled air traffic for the years 2000 to 2010 as well as forecasted emissions until the year 2030. In a baseline scenario of the forecast, input assumptions (e.g. traffic growth rates) are in line with predictions by the aircraft industry. Considering the effects of advanced technologies of the short-term and medium-term future, the forecast focusses on fuel consumption and emissions of nitric oxides. Calculations for historical air traffic additionally cover emissions of carbon monoxide, unburned hydrocarbons and soot. Results are validated against reference data including studies by the International Civil Aviation Organization (ICAO) and simulation results from international research projects. (orig.)

  19. An evaluation model for air quality in underground uranium mines based on integrated scale index on weights of generalized contrast

    International Nuclear Information System (INIS)

    The shortcomings of traditional methods for evaluating air quality in underground uranium mines are analysis. Based on the analysis results and the principle that the concentration of the contaminants in a mine varies in a constant ratio and the degree of their hazard varies in an arithmetic progression, the evaluating indicators were determined for the air quality in a uranium mine, and an evaluation model was proposed for the evaluation of the air quality in a uranium mine based on integrated scale index on weights of generalized contrast. the model overcomes the shortcoming of traditional methods that the radiation hazard is considered mainly in all these methods. the model was used to evaluate the air quality of four places in an underground uranium mine, the grade of the air quality and the correspondingmeasures for controlling the air quality in the four places are determined. The evaluation results show that the model is applicable to the design of a ventilation system for an underground uranium mine and the evaluation of the air quality in the system. (authors)

  20. Inflation in a modified radiative seesaw model

    CERN Document Server

    Kashiwase, Shoichi

    2015-01-01

    A radiative seesaw model with an inert doublet dark matter is a promising candidate which could explain the existence of neutrino masses, dark matter and baryon number asymmetry of the Universe, simultaneously. In addition to these issues, inflation should also be explained since the recent CMB observations suggest the existence of the inflationary era at the early stage of the Universe. Thus, we extend it by a complex scalar field with a specific potential. This scaler could also be related to the neutrino mass generation at a TeV scale. We show that the inflation favored by the CMB observations could be realized even if inflaton takes sub-Plankian values during inflation.

  1. Measurement and Modeling of Particle Radiation in Coal Flames

    DEFF Research Database (Denmark)

    Bäckström, Daniel; Johansson, Robert; Andersson, Klas Jerker; Johnsson, Filip; Clausen, Sønnik; Fateev, Alexander

    2014-01-01

    flame. Spectral radiation, total radiative intensity, gas temperature, and gas composition were measured, and the radiative intensity in the furnace was modeled with an axisymmetric cylindrical radiation model using Mie theory for the particle properties and a statistical narrow-band model for the gas...... properties. The in-flame particle radiation was measured with a Fourier transform infrared (FTIR) spectrometer connected to a water-cooled probe via fiber optics. In the cross-section of the flame investigated, the particles were found to be the dominating source of radiation. Apart from giving information......This work aims at developing a methodology that can provide information of in-flame particle radiation in industrial-scale flames. The method is based on a combination of experimental and modeling work. The experiments have been performed in the high-temperature zone of a 77 kWth swirling lignite...

  2. Asian Dust particles impacts on air quality and radiative forcing over Korea

    International Nuclear Information System (INIS)

    Asian Dust particles originated from the deserts and loess areas of the Asian continent are often transported over Korea, Japan, and the North Pacific Ocean during spring season. Major air mass pathway of Asian dust storm to Korea is from either north-western Chinese desert regions or north-eastern Chinese sandy areas. The local atmospheric environment condition in Korea is greatly impacted by Asian dust particles transported by prevailing westerly wind. Since these Asian dust particles pass through heavily populated urban and industrial areas in China before it reach Korean peninsular, their physical, chemical and optical properties vary depending on the atmospheric conditions and air mass pathway characteristics. An integrated system approach has been adopted at the Advanced Environment Monitoring Research Center (ADEMRC), Gwangju Institute Science and Technology (GIST), Korea for effective monitoring of atmospheric aerosols utilizing various in-situ and optical remote sensing methods, which include a multi-channel Raman LIDAR system, sunphotometer, satellite, and in-situ instruments. Results from recent studies on impacts of Asian dust particles on local air quality and radiative forcing over Korea are summarized here.

  3. Study of radiation-induced modification of FEP in nitrogen and air atmospheres

    International Nuclear Information System (INIS)

    Fluoropolymers are a class of polymer with specific characteristics like chemical inertia and stability under aggressive chemical environmental. These properties are a consequence of the chemical structure, C-F bonds. Poli (tetrafluoroethylene-co-hexafluoropropylene) (FEP) is inserting in these class of polymer. FEP has good chemical and physical resistance, its working in temperature of 200 degree C and has a surface extremely smooth. This polymer is used as component in films, coatings, tapes, wires and cables in a variety of industries including telecommunications, semiconductor, chemical, food processing and packaging. In this study was used film with 100mm of thickness that were submitted to gamma radiation under nitrogen and air atmospheres in order to observe the effect of atmosphere in the polymer matrix. The irradiated doses were: 5, 10, 20, 40 and 80kGy at room temperature. The characterization was made by thermogravimetric analysis (TG), scanning electron microscope (SEM) and infrared spectroscopy using attenuate reflectance (ATR-IR). The TG analysis shown two degradation steps and for the samples irradiated under air the initial degradation began 10 degrees earlier than the samples irradiated under nitrogen. After the analysis, the results obtained were expected: the degradation reactions occurred in the samples irradiated under air atmosphere and the film has no changes in the structure when was irradiated under nitrogen atmosphere. (author)

  4. Study of radiation-induced modification of FEP in nitrogen and air atmospheres

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Camila P.; Zen, Heloisa A.; Lugao, Ademar B., E-mail: helozen@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    Fluoropolymers are a class of polymer with specific characteristics like chemical inertia and stability under aggressive chemical environmental. These properties are a consequence of the chemical structure, C-F bonds. Poli (tetrafluoroethylene-co-hexafluoropropylene) (FEP) is inserting in these class of polymer. FEP has good chemical and physical resistance, its working in temperature of 200 degree C and has a surface extremely smooth. This polymer is used as component in films, coatings, tapes, wires and cables in a variety of industries including telecommunications, semiconductor, chemical, food processing and packaging. In this study was used film with 100mm of thickness that were submitted to gamma radiation under nitrogen and air atmospheres in order to observe the effect of atmosphere in the polymer matrix. The irradiated doses were: 5, 10, 20, 40 and 80kGy at room temperature. The characterization was made by thermogravimetric analysis (TG), scanning electron microscope (SEM) and infrared spectroscopy using attenuate reflectance (ATR-IR). The TG analysis shown two degradation steps and for the samples irradiated under air the initial degradation began 10 degrees earlier than the samples irradiated under nitrogen. After the analysis, the results obtained were expected: the degradation reactions occurred in the samples irradiated under air atmosphere and the film has no changes in the structure when was irradiated under nitrogen atmosphere. (author)

  5. Equivalent Air Spring Suspension Model for Quarter-Passive Model of Passenger Vehicles

    OpenAIRE

    Abid, Haider J.; Chen, Jie; Nassar, Ameen A.

    2015-01-01

    This paper investigates the GENSIS air spring suspension system equivalence to a passive suspension system. The SIMULINK simulation together with the OptiY optimization is used to obtain the air spring suspension model equivalent to passive suspension system, where the car body response difference from both systems with the same road profile inputs is used as the objective function for optimization (OptiY program). The parameters of air spring system such as initial pressure, volume of bag, l...

  6. The Impact of Physical Atmosphere on Air Quality and the Utility of Satellite Observations in Air Quality Models

    Science.gov (United States)

    Pour Biazar, A.; McNider, R. T.; Park, Y. H.; Doty, K.; Khan, M. N.; Dornblaser, B.

    2012-12-01

    Physical atmosphere significantly impacts air quality as it regulates production, accumulation, and transport of atmospheric pollutants. Consequently, air quality simulations are greatly influenced by the uncertainties that emanates from the simulation of physical atmosphere. Since air quality model predictions are increasingly being used in health studies, regulatory applications, and policy making, reducing such uncertainties in model simulations is of outmost importance. This paper describes some of the critical aspects of physical atmosphere affecting air quality models that can be improved by utilizing satellite observations. Retrievals of skin temperature, surface albedo, surface insolation, cloud top temperature and cloud reflectance obtained from the Geostationary Operational Environmental Satellite (GOES) by NASA/MSFC GOES Product Generation System (GPGS) have been utilized to improve the air quality simulations used in the State Implementation Plan (SIP) attainment demonstrations. Satellite observations of ground temperature are used to recover surface moisture and heat capacity and thereby improving model simulation of air temperature. Observations of clouds are utilized to improve the photochemical reaction rates within the photochemical model and also to assimilate clouds in the meteorological model. These techniques have been implemented and tested in some of the widely used air quality decision modeling systems such as MM5/WRF/CMAQ/CAMx. The results from these activities show significant improvements in air quality simulations.

  7. Guidelines and Technical Information Provided by the US Federal Aviation Administration to Promote Radiation Safety for Air Carrier Crew Members

    International Nuclear Information System (INIS)

    The Federal Aviation Administration has provided instructional material on radiation exposure during air travel, supported research on radiation effects, and developed computer programs (CARI) for estimating the galactic radiation in the atmosphere. Based on a recent version of CARI, estimates are presented of effective dose rates of galactic radiation and the percentage contributions by its components, for the years 1958 through 1997, at various altitudes both at the equator and at a high latitude. Also presented are the effective doses of galactic radiation received on a variety of US domestic and transoceanic flights (flight doses). Incorporating flight doses, estimates were made of the total annual doses received by aircrew members from occupational plus non-occupational natural radiation sources. Annual doses to crew members, on and off the job, ranged from almost identical to about twice the average annual effective dose of natural background radiation received by a member of the US population. (author)

  8. Modeling plasma actuators with air chemistry for effective flow control

    International Nuclear Information System (INIS)

    An asymmetric dielectric barrier discharge model is presented for real gas air chemistry using a self-consistent multibody system of plasma, dielectric, and neutral gas modeled together to predict the electrodynamic force imparted to the working gas. The equations governing the motion of charged and neutral species are solved with Poisson equation using finite element method using a Galerkin weak formulation. Electric field profile changes with the increase in grounded electrode and the density increases downstream. The electrodynamic force development mechanism is studied over a flat plate due to charge and neutral species production from adjacent air in a radio frequency driven barrier discharge. The time average of the force shows mostly acceleration above the actuator. Numerical simulation confirms that the magnitude of force increases very slightly with the increase in the length of grounded electrode

  9. A mathematical model for radiation hydrodynamics

    Directory of Open Access Journals (Sweden)

    Sebastiano Pennisi

    1990-11-01

    Full Text Available We adopt here the idea of describing a radiation field by means of the radiation energy density E and the radiative flux vector F which must satisfy a set of evolution equations; in these equations an unknown tensorial function P(E,F appears that is determined by the methods of extended thermodynamics.

  10. Seine estuary modelling and AirSWOT measurements validation

    Science.gov (United States)

    Chevalier, Laetitia; Lyard, Florent; Laignel, Benoit

    2013-04-01

    In the context of global climate change, knowing water fluxes and storage, from the global scale to the local scale, is a crucial issue. The future satellite SWOT (Surface Water and Ocean Topography) mission, dedicated to the surface water observation, is proposed to meet this challenge. SWOT main payload will be a Ka-band Radar Interferometer (KaRIn). To validate this new kind of measurements, preparatory airborne campaigns (called AirSWOT) are currently being designed. AirSWOT will carry an interferometer similar to Karin: Kaspar-Ka-band SWOT Phenomenology Airborne Radar. Some campaigns are planned in France in 2014. During these campaigns, the plane will fly over the Seine River basin, especially to observe its estuary, the upstream river main channel (to quantify river-aquifer exchange) and some wetlands. The present work objective is to validate the ability of AirSWOT and SWOT, using a Seine estuary hydrodynamic modelling. In this context, field measurements will be collected by different teams such as GIP (Public Interest Group) Seine Aval, the GPMR (Rouen Seaport), SHOM (Hydrographic and Oceanographic Service of the Navy), the IFREMER (French Research Institute for Sea Exploitation), Mercator-Ocean, LEGOS (Laboratory of Space Study in Geophysics and Oceanography), ADES (Data Access Groundwater) ... . These datasets will be used first to validate locally AirSWOT measurements, and then to improve a hydrodynamic simulations (using tidal boundary conditions, river and groundwater inflows ...) for AirSWOT data 2D validation. This modelling will also be used to estimate the benefit of the future SWOT mission for mid-latitude river hydrology. To do this modelling,the TUGOm barotropic model (Toulouse Unstructured Grid Ocean model 2D) is used. Preliminary simulations have been performed by first modelling and then combining to different regions: first the Seine River and its estuarine area and secondly the English Channel. These two simulations h are currently being improved, by testing different roughness coefficients, adding tributary inflows. Groundwater contributions will also be introduced (digital TUGOm development in progress) . The model outputs will be validated using data from the GPMR tide gauge data and measurements from the Topex/Poseidon and Jason-1/-2 altimeters for year 2007.

  11. Dynamic evaluation of air quality models over European regions

    Science.gov (United States)

    Thunis, P.; Pisoni, E.; Degraeuwe, B.; Kranenburg, R.; Schaap, M.; Clappier, A.

    2015-06-01

    Chemistry-transport models are increasingly used in Europe for estimating air quality or forecasting changes in pollution levels. But with this increased use of modeling arises the need of harmonizing the methodologies to determine the quality of air quality model applications. This is complex for planning applications, i.e. when models are used to assess the impact of realistic or virtual emission scenarios. In this work, the methodology based on the calculation of potencies proposed by Thunis and Clappier (2014) to analyze the model responses to emission reductions is applied on three different domains in Europe (Po valley, Southern Poland and Flanders). This methodology is further elaborated to facilitate the inter-comparison process and bring in a single diagram the possibility of differentiating long-term from short-term effects. This methodology is designed for model users to interpret their model results but also for policy-makers to help them defining intervention priorities. The methodology is applied to both daily PM10 and 8 h daily maximum ozone.

  12. Radiolytic yield of ozone in air for low dose neutron and x-ray/gamma-ray radiation

    International Nuclear Information System (INIS)

    Radiation ionizes surrounding air and produces molecular species, and these localized effects may be used as a signature of, and for quantification of, radiation. Low-level ozone production measurements from radioactive sources have been performed in this work to understand radiation chemical yields at low doses. The University of New Mexico AGN-201 M reactor was used as a tunable radiation source. Ozone levels were compared between reactor-on and reactor-off conditions, and differences (0.61 to 0.73 ppb) well below background levels were measured. Simulations were performed to determine the dose rate distribution and average dose rate to the air sample within the reactor, giving 35 mGy of mixed photon and neutron dose. A radiation chemical yield for ozone of 6.5±0.8 molecules/100 eV was found by a variance weighted average of the data. The different contributions of photons and neutrons to radiolytic ozone production are discussed. - Highlights: • Localized ozone production in air may be an indicator of radioactive material. • Radiolytic ozone work is dominated by high radiation fields in the saturation regime. • For low level measurements we used a reactor as a mixed photon/neutron source. • Monte Carlo simulations were performed to understand the dose profile to air. • Different contributions to ozone production are discussed for neutrons and photons

  13. A Polyethylene Chamber for Use in Physical Modelling of the Heat Exchange on Surfaces Exposed to a Radiation Regime

    Science.gov (United States)

    Okada, Maki; Okada, Masumi; Kusaka, Hiroyuki

    2014-07-01

    Bodies located in outdoor environments are radiatively heated in the daytime and cooled at night. Convective heat transfer is subsequently activated between the body surface and the surrounding air. To investigate these heat-exchange processes, we developed a new apparatus, referred to as a "polyethylene chamber", for use in physical model experiments. The chamber is a 1.51-m-long tube with the ends serving as the air inlet and outlet, and is ventilated in the longitudinal direction by using an exhaust fan. The measurement section of the chamber is open but otherwise the device is covered with 0.02-mm-thick polyethylene film. Because such thin polyethylene film transmits approximately 85 % of both shortwave and longwave radiation, the model surface in the chamber is exposed to a radiation level almost equivalent to the outdoor radiation level. For example, at night the surface of the model is cooled by radiation, and subsequently, the air inside the chamber is cooled by the surface. Consequently, the outlet air temperature becomes lower than the inlet air temperature. The use of this temperature difference between the air inlet and outlet, together with other heat balance components, is a unique approach to the chamber technique for evaluating the heat exchange rate at a model's surface. This report describes the design and heat balance of the chamber, and compares the heat-balance-based approach with another approach based on the radiation-convection balance on the model surface. To demonstrate the performance of the polyethylene chamber, two chambers were exposed to outdoor radiation on a clear night; one contained a leaf model. Air and surface temperatures were measured and the convective heat flux at the surfaces of the model and floor surface were calculated from the heat balance components of the chambers by assuming steady-state heat transfer. The fluxes agreed closely with those obtained from the radiation-convection balance at the model or floor surface. The results also clearly showed that the air flowing in the polyethylene chamber was cooled more efficiently when the model surface was installed in the chamber, even though the model surface temperature was high.

  14. Measurement and modeling of cloud condensation nuclei in continental air

    OpenAIRE

    Rose, Diana

    2010-01-01

    Atmospheric aerosol particles serving as cloud condensation nuclei (CCN) are key elements of the hydrological cycle and climate. Knowledge of the spatial and temporal distribution of CCN in the atmosphere is essential to understand and describe the effects of aerosols in meteorological models. In this study, CCN properties were measured in polluted and pristine air of different continental regions, and the results were parameterized for efficient prediction of CCN concentrations.The continuou...

  15. CFD model of air movement in ventilated faade: comparison between natural and forced air flow

    Directory of Open Access Journals (Sweden)

    Miguel Mora Prez, Gonzalo Lpez Patio, P. Amparo Lpez Jimnez

    2013-01-01

    Full Text Available This study describes computational fluid dynamics (CFD modeling of ventilated faade. Ventilated faades are normal faade but it has an extra channel between the concrete wall and the (double skin faade. Several studies found in the literature are carried out with CFD simulations about the behavior of the thermodynamic phenomena of the double skin faades systems. These studies conclude that the presence of the air gap in the ventilated faade affects the temperature in the building skin, causing a cooling effect, at least in low-rise buildings. One of the most important factors affecting the thermal effects of ventilated faades is the wind velocity. In this contribution, a CFD analysis applied on two different velocity assumptions for air movement in the air gap of a ventilated faade is presented. A comparison is proposed considering natural wind induced velocity with forced fan induced velocity in the gap. Finally, comparing temperatures in the building skin, the differences between both solutions are described determining that, related to the considered boundary conditions, there is a maximum height in which the thermal effect of the induced flow is significantly observed.

  16. Space radiation-associated lung injury in a murine model.

    Science.gov (United States)

    Christofidou-Solomidou, Melpo; Pietrofesa, Ralph A; Arguiri, Evguenia; Schweitzer, Kelly S; Berdyshev, Evgeny V; McCarthy, Maureen; Corbitt, Astrid; Alwood, Joshua S; Yu, Yongjia; Globus, Ruth K; Solomides, Charalambos C; Ullrich, Robert L; Petrache, Irina

    2015-03-01

    Despite considerable progress in identifying health risks to crewmembers related to exposure to galactic/cosmic rays and solar particle events (SPE) during space travel, its long-term effects on the pulmonary system are unknown. We used a murine risk projection model to investigate the impact of exposure to space-relevant radiation (SR) on the lung. C3H mice were exposed to (137)Cs gamma rays, protons (acute, low-dose exposure mimicking the 1972 SPE), 600 MeV/u (56)Fe ions, or 350 MeV/u (28)Si ions at the NASA Space Radiation Laboratory at Brookhaven National Laboratory. Animals were irradiated at the age of 2.5 mo and evaluated 23.5 mo postirradiation, at 26 mo of age. Compared with age-matched nonirradiated mice, SR exposures led to significant air space enlargement and dose-dependent decreased systemic oxygenation levels. These were associated with late mild lung inflammation and prominent cellular injury, with significant oxidative stress and apoptosis (caspase-3 activation) in the lung parenchyma. SR, especially high-energy (56)Fe or (28)Si ions markedly decreased sphingosine-1-phosphate levels and Akt- and p38 MAPK phosphorylation, depleted anti-senescence sirtuin-1 and increased biochemical markers of autophagy. Exposure to SR caused dose-dependent, pronounced late lung pathological sequelae consistent with alveolar simplification and cellular signaling of increased injury and decreased repair. The associated systemic hypoxemia suggested that this previously uncharacterized space radiation-associated lung injury was functionally significant, indicating that further studies are needed to define the risk and to develop appropriate lung-protective countermeasures for manned deep space missions. PMID:25526737

  17. Estimation of Global Solar Radiation in Rwanda Using Empirical Models

    Directory of Open Access Journals (Sweden)

    B. Safari

    2009-01-01

    Full Text Available Understanding solar radiation data is essential for modeling solar energy systems. The purpose of the present study was to estimate global solar radiation on horizontal surface using sunshine-based models. Angström-type polynomials of first and second order have been developed from long term records of monthly mean daily sunshine hour values and measured daily global solar radiation on horizontal surface at Kigali, Rwanda. Coefficients of those polynomials were derived using least square regression analysis. These coefficients were then used for the estimation of solar radiation in other places of Rwanda where measures of solar radiation do not exist but sunshine records are available.

  18. Stochastic modeling of p53-regulated apoptosis upon radiation damage

    CERN Document Server

    Bhatt, Divesh; Bahar, Ivet

    2011-01-01

    We develop and study the evolution of a model of radiation induced apoptosis in cells using stochastic simulations, and identified key protein targets for effective mitigation of radiation damage. We identified several key proteins associated with cellular apoptosis using an extensive literature survey. In particular, we focus on the p53 transcription dependent and p53 transcription independent pathways for mitochondrial apoptosis. Our model reproduces known p53 oscillations following radiation damage. The key, experimentally testable hypotheses that we generate are - inhibition of PUMA is an effective strategy for mitigation of radiation damage if the treatment is administered immediately, at later stages following radiation damage, inhibition of tBid is more effective.

  19. Daily global solar radiation prediction from air temperatures using kernel extreme learning machine: A case study for Iran

    Science.gov (United States)

    Shamshirband, Shahaboddin; Mohammadi, Kasra; Chen, Hui-Ling; Narayana Samy, Ganthan; Petković, Dalibor; Ma, Chao

    2015-11-01

    Lately, the kernel extreme learning machine (KELM) has gained considerable importance in the scientific area due to its great efficiency, easy implementation and fast training speed. In this paper, for the first time the potential of KELM to predict the daily horizontal global solar radiation from the maximum and minimum air temperatures (Tmax and Tmin) is appraised. The effectiveness of the proposed KELM method is evaluated against the grid search based support vector regression (SVR), as a robust methodology. Three KELM and SVR models are developed using different input attributes including: (1) Tmin and Tmax, (2) Tmin and Tmax-Tmin, and (3) Tmax and Tmax-Tmin. The achieved results reveal that the best predictions precision is achieved by models (3). The achieved results demonstrate that KELM offers favorable predictions and outperforms the SVR. For the KELM (3) model, the obtained statistical parameters of mean absolute bias error, root mean square error, relative root mean square error and correlation coefficient are 1.3445 MJ/m2, 2.0164 MJ/m2, 11.2464% and 0.9057%, respectively for the testing data. As further examination, a month-by-month evaluation is conducted and found that in six months from May to October the KELM (3) model provides further accuracy than overall accuracy. Based upon the relative root mean square error, the KELM (3) model shows excellent capability in the period of April to October while in the remaining months represents good performance.

  20. Space-Time Fusion Under Error in Computer Model Output: An Application to Modeling Air Quality

    Science.gov (United States)

    In the last two decades a considerable amount of research effort has been devoted to modeling air quality with public health objectives. These objectives include regulatory activities such as setting standards along with assessing the relationship between exposure to air pollutan...

  1. Angular radiation models for Earth-atmosphere system. Volume 1: Shortwave radiation

    Science.gov (United States)

    Suttles, J. T.; Green, R. N.; Minnis, P.; Smith, G. L.; Staylor, W. F.; Wielicki, B. A.; Walker, I. J.; Young, D. F.; Taylor, V. R.; Stowe, L. L.

    1988-01-01

    Presented are shortwave angular radiation models which are required for analysis of satellite measurements of Earth radiation, such as those fro the Earth Radiation Budget Experiment (ERBE). The models consist of both bidirectional and directional parameters. The bidirectional parameters are anisotropic function, standard deviation of mean radiance, and shortwave-longwave radiance correlation coefficient. The directional parameters are mean albedo as a function of Sun zenith angle and mean albedo normalized to overhead Sun. Derivation of these models from the Nimbus 7 ERB (Earth Radiation Budget) and Geostationary Operational Environmental Satellite (GOES) data sets is described. Tabulated values and computer-generated plots are included for the bidirectional and directional modes.

  2. Effect of clean indoor air laws on smokers: the clean air module of the SimSmoke computer simulation model

    OpenAIRE

    Levy, D.; Friend, K; Polishchuk, E.

    2001-01-01

    OBJECTIVES—To develop a simulation model to examine the effects of clean indoor air laws on prevalence rates and smoking attributable deaths.
METHODS—Based on empirical and theoretical research, the effects of clean air laws are modelled by type of law. The model considers clean air laws at the state levels between 1993 and 2000, and projects the number of smokers and smoking attributable deaths in the USA under different scenarios from 2000 onward.
RESULTS—The model predicts that comprehensi...

  3. EMMA model: an advanced operational mesoscale air quality model for urban and regional environments

    International Nuclear Information System (INIS)

    Mesoscale air quality models are an important tool to forecast and analyse the air quality in regional and urban areas. In recent years an increased interest has been shown by decision makers in these types of software tools. The complexity of such a model has grown exponentially with the increase of computer power. Nowadays, medium workstations can run operational versions of these modelling systems successfully. Presents a complex mesoscale air quality model which has been installed in the Environmental Office of the Madrid community (Spain) in order to forecast accurately the ozone, nitrogen dioxide and sulphur dioxide air concentrations in a 3D domain centred on Madrid city. Describes the challenging scientific matters to be solved in order to develop an operational version of the atmospheric mesoscale numerical pollution model for urban and regional areas (ANA). Some encouraging results have been achieved in the attempts to improve the accuracy of the predictions made by the version already installed. (Author)

  4. Effects of model resolution on entrainment (inversion heights), cloud-radiation interactions, and cloud radiative forcing

    OpenAIRE

    H. Guo; Y. LIU; P. H. Daum; Zeng, X.; Li, X.; Tao, W.-K.

    2008-01-01

    We undertook three-dimensional numerical studies of a marine stratus deck under a strong inversion using an interactive shortwave- and longwave-radiation module. A suite of sensitivity tests were conducted to address the effects of model resolution on entrainment (inversion heights), cloud-radiation interactions, and cloud radiative-forcings by varying model horizontal resolution only, varying vertical resolution only, and varying horizontal- and vertical-resolution simultan...

  5. Improved estimate of global dust radiative forcing using a coupled chemical transport-radiative transfer model

    OpenAIRE

    Zhang, L; Li, Q. B.; Gu, Y.; Liou, K. N.; Meland, B.

    2013-01-01

    Atmospheric mineral dust particles exert significant direct radiative forcings and are critical drivers of climate change. Here, we use the GEOS-Chem global three-dimensional chemical transport model (3-D CTM) coupled online with the Fu-Liou-Gu (FLG) radiative transfer model (RTM) to investigate the dust radiative forcing and heating rates based on different dust vertical profiles. The coupled calculations using a realistic dust vertical profile simulated by GEOS-Chem minimize the phys...

  6. Effects of model resolution on entrainment (inversion heights), cloud-radiation interactions, and cloud radiative forcing

    OpenAIRE

    Guo, H; Liu, Y.(Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui, China); Daum, P. H.; Zeng, X.; Li, X; W.-K. Tao

    2008-01-01

    We undertook three-dimensional numerical studies of a marine stratus deck under a strong inversion using an interactive shortwave- and longwave-radiation module. A suite of sensitivity tests were conducted to address the effects of model resolution on entrainment (inversion heights), cloud-radiation interactions, and cloud radiative-forcings by varying model horizontal resolution only, varying vertical resolution only, and varying horizontal- and vertical-resolution simultaneously but with a ...

  7. Solutions Network Formulation Report. NASA's Potential Contributions for Using Solar Ultraviolet Radiation in Conjunction with Photocatalysis for Urban Air Pollution Mitigation and Increasing Air Quality

    Science.gov (United States)

    Underwood, Lauren; Ryan, Robert E.

    2007-01-01

    This Candidate Solution is based on using NASA Earth science research on atmospheric ozone and aerosols data as a means to predict and evaluate the effectiveness of photocatalytically created surfaces (building materials like glass, tile and cement) for air pollution mitigation purposes. When these surfaces are exposed to near UV light, organic molecules, like air pollutants and smog precursors, will degrade into environmentally friendly compounds. U.S. EPA (Environmental Protection Agency) is responsible for forecasting daily air quality by using the Air Quality Index (AQI) that is provided by AIRNow. EPA is partnered with AIRNow and is responsible for calculating the AQI for five major air pollutants that are regulated by the Clean Air Act. In this Solution, UV irradiance data acquired from the satellite mission Aura and the OMI Surface UV algorithm will be used to help understand both the efficacy and efficiency of the photocatalytic decomposition process these surfaces facilitate, and their ability to reduce air pollutants. Prediction models that estimate photocatalytic function do not exist. NASA UV irradiance data will enable this capability, so that air quality agencies that are run by state and local officials can develop and implement programs that utilize photocatalysis for urban air pollution control and, enable them to make effective decisions about air pollution protection programs.

  8. ANN-based modelling and estimation of daily global solar radiation data: A case study

    International Nuclear Information System (INIS)

    In this paper, an artificial neural network (ANN) models for estimating and modelling of daily global solar radiation have been developed. The data used in this work are the global irradiation HG, diffuse irradiation HD, air temperature T and relative humidity Hu. These data are available from 1998 to 2002 at the National Renewable Energy Laboratory (NREL) website. We have developed six ANN-models by using different combination as inputs: the air temperature, relative humidity, sunshine duration and the day of year. For each model, the output is the daily global solar radiation. Firstly, a set of 4 x 365 points (4 years) has been used for training each networks, while a set of 365 points (1 year) has been used for testing and validating the ANN-models. It was found that the model using sunshine duration and air temperature as inputs, gives good accurate results since the correlation coefficient is 97.65%. A comparative study between developed ANN-models and conventional regression models is presented in this study.

  9. A model for calculating room air and surface tritium concentrations

    International Nuclear Information System (INIS)

    A mathematical model and the resultant analytical solutions for calculation of transient tritium concentrations in room air and in solid surfaces are presented. Although more elaborate models exist for describing the behaviour of tritium released into enclosures, a simpler approach was considered adequate for a preliminary assessment of situations arising at JET. A comparison to experimental data and several cases of interest are also presented. These preliminary checks have confirmed that the basic approach is sound. Further checks and refinement may be required to cover the full range of practical situations. (author)

  10. Testing theoretical models of magnetic damping using an air track

    International Nuclear Information System (INIS)

    Magnetic braking is a long-established application of Lenz's law. A rigorous analysis of the laws governing this problem involves solving Maxwell's equations in a time-dependent situation. Approximate models have been developed to describe different experimental results related to this phenomenon. In this paper we present a new method for the analysis of magnetic braking using a magnet fixed to the glider of an air track. The forces acting on the glider, a result of the eddy currents, can be easily observed and measured. As a consequence of the air track inclination, the glider accelerates at the beginning, although it asymptotically tends towards a uniform rectilinear movement characterized by a terminal speed. This speed depends on the interaction between the magnetic field and the conductivity properties of the air track. Compared with previous related approaches, in our experimental setup the magnet fixed to the glider produces a magnetic braking force which acts continuously, rather than over a short period of time. The experimental results satisfactorily concur with the theoretical models adapted to this configuration

  11. Atmospheric radiative transfer modeling: a summary of the AER codes

    International Nuclear Information System (INIS)

    The radiative transfer models developed at AER are being used extensively for a wide range of applications in the atmospheric sciences. This communication is intended to provide a coherent summary of the various radiative transfer models and associated databases publicly available from AER (http://www.rtweb.aer.com). Among the communities using the models are the remote sensing community (e.g. TES, IASI), the numerical weather prediction community (e.g. ECMWF, NCEP GFS, WRF, MM5), and the climate community (e.g. ECHAM5). Included in this communication is a description of the central features and recent updates for the following models: the line-by-line radiative transfer model (LBLRTM); the line file creation program (LNFL); the longwave and shortwave rapid radiative transfer models, RRTMLW and RRTMSW; the Monochromatic Radiative Transfer Model (MonoRTM); the MTCKD Continuum; and the Kurucz Solar Source Function. LBLRTM and the associated line parameter database (e.g. HITRAN 2000 with 2001 updates) play a central role in the suite of models. The physics adopted for LBLRTM has been extensively analyzed in the context of closure experiments involving the evaluation of the model inputs (e.g. atmospheric state), spectral radiative measurements and the spectral model output. The rapid radiative transfer models are then developed and evaluated using the validated LBLRTM model

  12. Search for molecular bremsstrahlung radiation signals in Ku band with coincidental operations of radio telescopes with air shower detectors

    OpenAIRE

    Fukushima Masaki; Sakurai Nobuyuki; Fujii Toshihiro; Akimune Hidetoshi; Iijima Takashi; Kuramoto Kazuyuki; Yamamoto Tokonatsu; Ogio Shoichi; Sagawa Hiroyuki

    2013-01-01

    Microwave radiation from extensive air showers is expected to provide a new technique to observe UHECR. We insatlled and operate radio telescopes in Osaka and at Telescope Array site in Utah, USA. In Osaka, we are coincidentally operating two Ku band radio telescopes with an air shower array which consists of nine plastic scintillators with about 10 m separation. In Utah, we installed two telescopes just beside the Black Rock Mesa fluorescence detector (FD) station of the Telescope Array expe...

  13. A radiation-derived temperature-index snow routine for the GSSHA hydrologic model

    Science.gov (United States)

    Follum, Michael L.; Downer, Charles W.; Niemann, Jeffrey D.; Roylance, Spencer M.; Vuyovich, Carrie M.

    2015-10-01

    Accurate estimation of snowpack is vital in many parts of the world for both water management and flood prediction. Temperature-index (TI) snowmelt models are commonly used for this purpose due to their simplicity and low data requirements. Although TI models work well within lumped watershed models, their reliance on air temperature (and potentially an assumed lapse rate) as the only external driver of snowmelt limits their ability to accurately simulate the spatial distribution of snowpack and thus the timing of snowmelt. This limitation significantly reduces the utility of the TI approach in distributed hydrologic models because spatial variability within the watershed, including snowpack and snowmelt, is usually the primary reason for selecting a distributed model. In this paper, a new radiation-derived temperature index (RTI) approach is presented that uses a spatially-varying proxy temperature in place of air temperature within the TI model of the fully-distributed Gridded Surface Subsurface Hydrologic Analysis (GSSHA) watershed model. The RTI is derived from a radiation balance and includes spatial heterogeneity in both shortwave and longwave radiation. Thus, the RTI accounts for more local variation in the available energy than air temperature alone. The RTI model in GSSHA is tested at the Senator Beck basin in southwestern Colorado where observations for snow water equivalent (SWE) and LandSat-derived images of snow cover area (SCA) are available. The TI and RTI approaches produce similar SWE estimates at two non-forested and relatively flat sites with SWE observations. However, the two models can produce very different SWE values at sites with forests or topographic slopes, which leads to significant differences in the basin-wide SWE values of the two models. Furthermore, the RTI model provides better basin-wide SCA estimates than the TI model in 75% of the LandSat images analyzed.

  14. Sunspot Modeling: From Simplified Models to Radiative MHD Simulations

    Directory of Open Access Journals (Sweden)

    Rolf Schlichenmaier

    2011-09-01

    Full Text Available We review our current understanding of sunspots from the scales of their fine structure to their large scale (global structure including the processes of their formation and decay. Recently, sunspot models have undergone a dramatic change. In the past, several aspects of sunspot structure have been addressed by static MHD models with parametrized energy transport. Models of sunspot fine structure have been relying heavily on strong assumptions about flow and field geometry (e.g., flux-tubes, "gaps", convective rolls, which were motivated in part by the observed filamentary structure of penumbrae or the necessity of explaining the substantial energy transport required to maintain the penumbral brightness. However, none of these models could self-consistently explain all aspects of penumbral structure (energy transport, filamentation, Evershed flow. In recent years, 3D radiative MHD simulations have been advanced dramatically to the point at which models of complete sunspots with sufficient resolution to capture sunspot fine structure are feasible. Here overturning convection is the central element responsible for energy transport, filamentation leading to fine-structure and the driving of strong outflows. On the larger scale these models are also in the progress of addressing the subsurface structure of sunspots as well as sunspot formation. With this shift in modeling capabilities and the recent advances in high resolution observations, the future research will be guided by comparing observation and theory.

  15. ADDRESSING HUMAN EXPOSURES TO AIR POLLUTANTS AROUND BUILDINGS IN URBAN AREAS WITH COMPUTATIONAL FLUID DYNAMICS MODELS

    Science.gov (United States)

    This paper discusses the status and application of Computational Fluid Dynamics (CFD) models to address challenges for modeling human exposures to air pollutants around urban building microenvironments. There are challenges for more detailed understanding of air pollutant sour...

  16. The dynamic test modeling of the air-operated valve

    International Nuclear Information System (INIS)

    The prediction of AOV(Air-Operated Valve) performance is normally evaluated by the allowable operating thrust/torque margin for the opening and closing strokes. However, it is not easy to carry out the dynamic test measurement for all the valves in the nuclear power plant due to the safety and operating conditions. The analysis of the available and required thrust/torque for the valve is considered as the alternate method to turn around this obstacle. This paper discusses the dynamic modeling and the simulation for the diaphragm type air operated globe valve. The pressure difference is assumed as two kinds of variation - linear and curved shape- when the valve is opened or closed. SIMULINK in MATLAB was used for the simulation and the results show good agreement with the actual test done by previous research

  17. Modeling of external radiation from the transport of radionuclides across a canyon

    International Nuclear Information System (INIS)

    The Los Alamos Meson Physics Facility (LAMPF) is an 800-million electron volt, l mA intensity linear proton accelerator used for studying subatomic particles at relativistic velocities. Routine operation of the accelerator results in the formation of short-lived air activation products, primarily in the beam stop section of LAMPF. This study presents the results of monitoring and modeling external radiation levels from LAMPF emissions at three locations during 1984. Measured radiation exposures are presented for all three locations during a 49-day period. Hourly radiation levels are calculated for all sites and compared with the prevalent wind patterns during the study period. Predicted daily levels are compared with measured values at all of the sites. Accuracy of the model is compared for day and night conditions. Annual model predictions are also compared with TLD measurements

  18. Radiation protection at the RA reactor, 1987 - Part IIb: Environmental radioactivity control, Air radioactivity control

    International Nuclear Information System (INIS)

    During the period from November 1985 - November 1988, within the radioactivity control on the Vinca Institute site air contamination radioactive aerosol contents was measured. Control was done on 4 measuring stations, two in the Institute and two locations in the direction of wind i.e. Belgrade, 2 km and 7 km away from the Institute respectively. This position of the measuring locations enables control of radiation safety of the Institute, as well as environment of Belgrade taking into account the existence of the reactor and other possible contaminants in the Institute. It is mentioned that the state of the measuring instrumentation is unchanged compared to the previous years and does not provide the possibility of proper program for environmental radioactivity control

  19. Radiation carbonization of cellulose, wood and lignin in the presence of air

    International Nuclear Information System (INIS)

    The process of radiaton carbonization of wood and its separate components (cellulose and lignin) under the effect of γ-radiation is studied. In the process of cellulose and wood meal irradiation a decrease in hydrogen content with the growth of irradiation dose is observed. Simultaneously with hydrogen loss the dose of ∼ 100 kGy an increase in carbon content and a decrease in oxygen content are observed. In wood meal carbon content decreases, oxygen content increases. In lignin the observed changes in the element composition do not exceed experimental error. The results obtained are considered from the viewpoint of dehydration of radicals, formed in the process of irradiation, as well as their oxidation by the air oxygen

  20. A rat model of radiation injury in the mandibular area

    OpenAIRE

    Sønstevold, Tonje; Johannessen, Anne Christine; Stuhr, Linda

    2015-01-01

    Background Radiation technology focuses on delivering the radiation as precisely as possible to the tumor, nonetheless both acute and long-term damage to surrounding normal tissue may develop. Injuries to the surrounding normal tissue after radiotherapy of head and neck cancer are difficult to manage. An animal model is needed to elucidate good treatment modalities. The aim of this study was to establish a rat model where a certain radiation dose gives reproducible tissue reactions in the ...

  1. Modelling and Experimental Investigations on Thermal Radiation in Combustion Environments

    OpenAIRE

    Hofgren, Henrik

    2015-01-01

    Thermal radiation is an important physical phenomenon in combustion environments. For the understanding of existing- and the design of new combustion environments computational modelling is a useful tool as it can describe the different transport phenomena. This thesis has focused on studying thermal radiative property models of the participating media, gases and particles. Two specific combustion environments have also been studied, from a thermal radiation perspective. The focus is on radia...

  2. Experimental synergy combining lidar measurements so as to optically characterize aerosols: applications to air quality and radiative forcing

    International Nuclear Information System (INIS)

    The work carried out in this study is devoted to a better understanding of the evolution of aerosol physical, chemical and optical properties for urban pollution aerosols, dust and biomass burning particles. It mainly concerns the complex refractive index and the single-scattering albedo. Such a characterisation is indeed necessary so as to fulfil the requirements of scientific and societal air quality and global climate evolution questions. Our study is based on a synergy between different measurements platforms: ground-based or airborne measurements, together with active and passive remote sensing observations. Lidar in particular turns out to be an essential tool in order to assess horizontal and vertical variability of aerosol micro-physical and optical properties in the atmospheric boundary layer, but also in the residual layer, as well as in layers transported from the boundary layer to the free troposphere. The original methodology we developed highlights the importance of the geographical origin, the impact of aging and dynamical processes in the evolution of structural, optical and hygroscopic aerosol features. The related accurate determination of the properties in each aerosol layer is required for radiative fluxes and heating rates calculations in the atmospheric column. The radiative impact of both dust particles and biomass burning aerosols observed over the region of Niamey (Niger) was thus assessed during the dry season. These results reveal the need of a better characterisation of those significant aerosol properties for each layer in models. (author)

  3. A Flexible Spatio-Temporal Model for Air Pollution with Spatial and Spatio-Temporal Covariates

    OpenAIRE

    Lindström, Johan; Szpiro, Adam A.; SAMPSON, Paul D.; Oron, Assaf P.; Richards, Mark; Larson, Tim V.; Sheppard, Lianne

    2013-01-01

    The development of models that provide accurate spatio-temporal predictions of ambient air pollution at small spatial scales is of great importance for the assessment of potential health effects of air pollution. Here we present a spatio-temporal framework that predicts ambient air pollution by combining data from several different monitoring networks and deterministic air pollution model(s) with geographic information system (GIS) covariates. The model presented in this paper has been implem...

  4. Testing models of new physics with UHE air shower observations

    CERN Document Server

    Allen, Jeffrey

    2013-01-01

    Several air shower observatories have established that the number of muons produced in UHE air showers is significantly larger than that predicted by models. We argue that the only solution to this muon deficit, compatible with the observed Xmax distributions, is to reduce the transfer of energy from the hadronic shower into the EM shower, by reducing the production or decay of pi0s. We present four different models of new physics, each with a theoretical rationale, which can accomplish this. One has a pure proton composition and three have mixed composition. Two entail new particle physics and suppress pi0 production or decay above LHC energies. The other two are less radical but nonetheless require significant modifications to existing hadron production models -- in one the changes are only above LHC energies and in the other the changes extend to much lower energies. We show that the models have distinctively different predictions for the correlation between the number of muons at ground and Xmax in hybrid...

  5. Urban scale air quality modelling using detailed traffic emissions estimates

    Science.gov (United States)

    Borrego, C.; Amorim, J. H.; Tchepel, O.; Dias, D.; Rafael, S.; Sá, E.; Pimentel, C.; Fontes, T.; Fernandes, P.; Pereira, S. R.; Bandeira, J. M.; Coelho, M. C.

    2016-04-01

    The atmospheric dispersion of NOx and PM10 was simulated with a second generation Gaussian model over a medium-size south-European city. Microscopic traffic models calibrated with GPS data were used to derive typical driving cycles for each road link, while instantaneous emissions were estimated applying a combined Vehicle Specific Power/Co-operative Programme for Monitoring and Evaluation of the Long-range Transmission of Air Pollutants in Europe (VSP/EMEP) methodology. Site-specific background concentrations were estimated using time series analysis and a low-pass filter applied to local observations. Air quality modelling results are compared against measurements at two locations for a 1 week period. 78% of the results are within a factor of two of the observations for 1-h average concentrations, increasing to 94% for daily averages. Correlation significantly improves when background is added, with an average of 0.89 for the 24 h record. The results highlight the potential of detailed traffic and instantaneous exhaust emissions estimates, together with filtered urban background, to provide accurate input data to Gaussian models applied at the urban scale.

  6. 3D Atmospheric Radiative Transfer for Cloud System-Resolving Models: Forward Modelling and Observations

    Energy Technology Data Exchange (ETDEWEB)

    Howard Barker; Jason Cole

    2012-05-17

    Utilization of cloud-resolving models and multi-dimensional radiative transfer models to investigate the importance of 3D radiation effects on the numerical simulation of cloud fields and their properties.

  7. Sensitivity analysis of thermal predictions to the modeling of direct solar radiation entering a zone

    OpenAIRE

    Goethals, Kim; Laverge, Jelle; Janssens, Arnold

    2009-01-01

    Because of high computational costs of computational fluid dynamics multi-zone energy simulation is currently appraised. Yet, the use of empirical correlations to predict interior convective heat transfer (CHT) limits the reliability of building comfort and energy analysis. As most of these convection algorithms depend, partially, on the temperature difference between the concerned surface and the air, the influence of the modeling of incoming direct solar radiation is studied. Simulations of...

  8. The radiation budget of a Cirrus layer deduced from simultaneous aircraft observations and model calculations

    Science.gov (United States)

    Ackerman, Thomas P.; Kinne, Stefan A.; Heymsfield, Andrew J.; Valero, Francisco P. J.

    1990-01-01

    Several aircraft were employed during the FIRE Cirrus IFO in order to make nearly simultaneous observations of cloud properties and fluxes. A segment of the flight data collected on 28 October 1988 during which the NASA Ames ER-2 overflew the NCAR King Air was analyzed. The ER-2 flew at high altitude making observations of visible and infrared radiances and infrared flux and cloud height and thickness. During this segment, the King Air flew just above the cloud base making observations of ice crystal size and shape, local meteorological variables, and infrared fluxes. While the two aircraft did not collect data exactly coincident in space and time, they did make observations within a few minutes of each other. For this case study, the infrared radiation balance of the cirrus layer is of primary concern. Observations of the upwelling 10 micron radiance, made from the ER-2, can be used to deduce the 10 micron optical depth of the layer. The upwelling broadband infrared flux is also measured from the ER-2. At the same time, the upwelling and downwelling infrared flux at the cloud base is obtained from the King Air measurements. Information on cloud microphysics is also available from the King Air. Using this data in conjunction with atmospheric temperature and humidity profiles from local radiosondes, the necessary inputs for an infrared radiative transfer model can be developed. Infrared radiative transfer calculations are performed with a multispectral two-stream model. The model fluxes at the cloud base and at 19 km are then compared with the aircraft observations to determine whether the model is performing well. Cloud layer heating rates can then be computed from the radiation exchange.

  9. Gamma radiation exposure of air crew in Tehran-Bandarabbas flights

    International Nuclear Information System (INIS)

    Different researches have been performed on natural exposure of cosmic rays and their effects on the human health. Monitoring of cosmic derived gamma ray exposure of air crews and passengers is the subject of the current study. In this paper, the control able variations of the cosmic ray flux in the atmosphere and the cosmic radiation exposure at flight altitudes will be discussed. For this study, the exposure rates to gamma ray, in an energy range of 50 keV-1.5 MeV, for the Tehran-Bandarabbas air flights have been measured. The results show that the maximum dose rate at 3000 ft (about 9 km) is 15-20 times higher than on the ground base. Also, the dose rate for this pathway is about 1.87?Sv/h which for 500 hours flights per year it is estimatal to be 935?Sv. This number is less than human permissible dose rate of 1 mSv/year.

  10. Air

    International Nuclear Information System (INIS)

    In recent years several regulations and standards for air quality and limits for air pollution were issued or are in preparation by the European Union, which have severe influence on the environmental monitoring and legislation in Austria. This chapter of the environmental control report of Austria gives an overview about the legal situation of air pollution control in the European Union and in specific the legal situation in Austria. It gives a comprehensive inventory of air pollution measurements for the whole area of Austria of total suspended particulates, ozone, volatile organic compounds, nitrogen oxides, sulfur dioxide, carbon monoxide, heavy metals, benzene, dioxin, polycyclic aromatic hydrocarbons and eutrophication. For each of these pollutants the measured emission values throughout Austria are given in tables and geographical charts, the environmental impact is discussed, statistical data and time series of the emission sources are given and legal regulations and measures for an effective environmental pollution control are discussed. In particular the impact of fossil-fuel power plants on the air pollution is analyzed. (a.n.)

  11. A photochemical box model for urban air quality study

    International Nuclear Information System (INIS)

    The photochemical box model (PBM) is based on the principle of mass conservation. The concentration of any pollutant is determined by horizontal advection, vertical entrainment, source emissions, and chemical reactions. A one dimensional high resolution boundary layer model by Blackadar has been further developed by considering the effect of urban heat islands to simulate the variation of the mixed layer height and incorporated in the PBM. The model predicted mixed layer height is a significant improvement over the characteristic mixed layer growth curve used in the original PBM by Schere and Demerjian. The gas phase chemical kinetic mechanism used in the Regional Acid Deposition Study II (RADM2) and Demerjian chemical mechanism have been used to calculate the contributions of chemical reactions to the changes of pollutant concentrations. Detailed analysis and comparisons of the two chemical mechanisms have been made. The simulated pollutant concentration using both chemical mechanisms are in very good agreement with observations. A radiative transfer model developed by Madronich has been incorporated in the PBM for the calculation of actinic flux and photolytic rate constants. Height averaged and radiation corrected photolytic rate constant are used for the photochemical reactions. The simulated pollutant concentrations for CO, NO, NO2 and Os are in very good agreement with observations. Sensitivities of model results to the variation of photolytic rate constants, boundary conditions, hydrocarbon speciation factors, and thermal rate constant have been tested

  12. Evaluation of the Community Multiscale Air Quality model version 5.1

    Science.gov (United States)

    The Community Multiscale Air Quality model is a state-of-the-science air quality model that simulates the emission, transport and fate of numerous air pollutants, including ozone and particulate matter. The Atmospheric Modeling and Analysis Division (AMAD) of the U.S. Environment...

  13. Computer modelling of statistical properties of SASE FEL radiation

    Science.gov (United States)

    Saldin, E. L.; Schneidmiller, E. A.; Yurkov, M. V.

    1997-06-01

    The paper describes an approach to computer modelling of statistical properties of the radiation from self amplified spontaneous emission free electron laser (SASE FEL). The present approach allows one to calculate the following statistical properties of the SASE FEL radiation: time and spectral field correlation functions, distribution of the fluctuations of the instantaneous radiation power, distribution of the energy in the electron bunch, distribution of the radiation energy after monochromator installed at the FEL amplifier exit and the radiation spectrum. All numerical results presented in the paper have been calculated for the 70 nm SASE FEL at the TESLA Test Facility being under construction at DESY.

  14. An integrated model for radiation induced cancer

    International Nuclear Information System (INIS)

    Risk estimates for radiation induced cancer are based on epidemiological data, principally the Japanese A bomb survivors. These estimates for radiation are better known than for any other environmental pollutant, but they do not relate directly to exposure to low doses and low dose rate. Recent rapid advances in molecular genetics, coupled with steady gains in cellular biology, radiation physics and chemistry led to the notion that the time may not be far off when it may be possible to arrive at human cancer risk estimates entirely from laboratory data. Whether risk estimates based on laboratory data will ever replace estimates based on epidemiological studies is an open question. What is clear is that laboratory data can supplement the present risk estimates by providing information on the relative effectiveness of high LET radiations, the importance of dose rate and dose protraction, and by identifying subpopulations which are unusually sensitive or resistant to radiation carcinogenesis. (author)

  15. X-ray radiation from the volume discharge in atmospheric-pressure air

    Science.gov (United States)

    Bratchikov, V. B.; Gagarinov, K. A.; Kostyrya, I. D.; Tarasenko, V. F.; Tkachev, A. N.; Yakovlenko, S. I.

    2007-07-01

    X-ray radiation from the volume discharge in atmospheric-pressure air is studied under the conditions when the voltage pulse rise time varies from 0.5 to 100 ns and the open-circuit voltage amplitude of the generator varies from 20 to 750 kV. It is shown that a volume discharge from a needle-like cathode forms at a relatively wide voltage pulse (to ≈60 ns in this work). The volume character of the discharge is due to preionization by fast electrons, which arise when the electric field concentrates at the cathode and in the discharge gap. As the voltage pulse rise time grows, X-ray radiation comes largely from the discharge gap in accordance with previous experiments. Propagation of fast avalanche electrons in nitrogen subjected to a nonuniform unsteady electric field is simulated. It is demonstrated that the amount of hard X-ray photons grows not only with increasing voltage amplitude but also with shortening pulse rise time.

  16. Improving ammonia emissions in air quality modelling for France

    Science.gov (United States)

    Hamaoui-Laguel, Lynda; Meleux, Frédérik; Beekmann, Matthias; Bessagnet, Bertrand; Génermont, Sophie; Cellier, Pierre; Létinois, Laurent

    2014-08-01

    We have implemented a new module to improve the representation of ammonia emissions from agricultural activities in France with the objective to evaluate the impact of such emissions on the formation of particulate matter modelled with the air quality model CHIMERE. A novel method has been set up for the part of ammonia emissions originating from mineral fertilizer spreading. They are calculated using the one dimensional 1D mechanistic model “VOLT'AIR” which has been coupled with data on agricultural practices, meteorology and soil properties obtained at high spatial resolution (cantonal level). These emissions display high spatiotemporal variations depending on soil pH, rates and dates of fertilization and meteorological variables, especially soil temperature. The emissions from other agricultural sources (animal housing, manure storage and organic manure spreading) are calculated using the national spatialised inventory (INS) recently developed in France. The comparison of the total ammonia emissions estimated with the new approach VOLT'AIR_INS with the standard emissions provided by EMEP (European Monitoring and Evaluation Programme) used currently in the CHIMERE model shows significant differences in the spatiotemporal distributions. The implementation of new ammonia emissions in the CHIMERE model has a limited impact on ammonium nitrate aerosol concentrations which only increase at most by 10% on the average for the considered spring period but this impact can be more significant for specific pollution episodes. The comparison of modelled PM10 (particulate matter with aerodynamic diameter smaller than 10 μm) and ammonium nitrate aerosol with observations shows that the use of the new ammonia emission method slightly improves the spatiotemporal correlation in certain regions and reduces the negative bias on average by 1 μg m-3. The formation of ammonium nitrate aerosol depends not only on ammonia concentrations but also on nitric acid availability, which is often a limiting factor in rural regions in France, and on meteorological conditions. The presented approach of ammonia emission calculation seems suitable for use in chemistry-transport models.

  17. A Neural Network Based Intelligent Predictive Sensor for Cloudiness, Solar Radiation and Air Temperature

    OpenAIRE

    Ferreira, Pedro M.; Ruano, António E.; João M. Gomes; Martins, Igor A. C.

    2012-01-01

    Accurate measurements of global solar radiation and atmospheric temperature, as well as the availability of the predictions of their evolution over time, are important for different areas of applications, such as agriculture, renewable energy and energy management, or thermal comfort in buildings. For this reason, an intelligent, light-weight and portable sensor was developed, using artificial neural network models as the time-series predictor mechanisms. These have been identified with...

  18. Evaluation of observation-fused regional air quality model results for population air pollution exposure estimation.

    Science.gov (United States)

    Chen, Gang; Li, Jingyi; Ying, Qi; Sherman, Seth; Perkins, Neil; Rajeshwari, Sundaram; Mendola, Pauline

    2014-07-01

    In this study, Community Multiscale Air Quality (CMAQ) model was applied to predict ambient gaseous and particulate concentrations during 2001 to 2010 in 15 hospital referral regions (HRRs) using a 36-km horizontal resolution domain. An inverse distance weighting based method was applied to produce exposure estimates based on observation-fused regional pollutant concentration fields using the differences between observations and predictions at grid cells where air quality monitors were located. Although the raw CMAQ model is capable of producing satisfying results for O3 and PM2.5 based on EPA guidelines, using the observation data fusing technique to correct CMAQ predictions leads to significant improvement of model performance for all gaseous and particulate pollutants. Regional average concentrations were calculated using five different methods: 1) inverse distance weighting of observation data alone, 2) raw CMAQ results, 3) observation-fused CMAQ results, 4) population-averaged raw CMAQ results and 5) population-averaged fused CMAQ results. It shows that while O3 (as well as NOx) monitoring networks in the HRRs are dense enough to provide consistent regional average exposure estimation based on monitoring data alone, PM2.5 observation sites (as well as monitors for CO, SO2, PM10 and PM2.5 components) are usually sparse and the difference between the average concentrations estimated by the inverse distance interpolated observations, raw CMAQ and fused CMAQ results can be significantly different. Population-weighted average should be used to account for spatial variation in pollutant concentration and population density. Using raw CMAQ results or observations alone might lead to significant biases in health outcome analyses. PMID:24747248

  19. Evaluation of Observation-Fused Regional Air Quality Model Results for Population Air Pollution Exposure Estimation

    Science.gov (United States)

    Chen, Gang; Li, Jingyi; Ying, Qi; Sherman, Seth; Perkins, Neil; Rajeshwari, Sundaram; Mendola, Pauline

    2014-01-01

    In this study, Community Multiscale Air Quality (CMAQ) model was applied to predict ambient gaseous and particulate concentrations during 2001 to 2010 in 15 hospital referral regions (HRRs) using a 36-km horizontal resolution domain. An inverse distance weighting based method was applied to produce exposure estimates based on observation-fused regional pollutant concentration fields using the differences between observations and predictions at grid cells where air quality monitors were located. Although the raw CMAQ model is capable of producing satisfying results for O3 and PM2.5 based on EPA guidelines, using the observation data fusing technique to correct CMAQ predictions leads to significant improvement of model performance for all gaseous and particulate pollutants. Regional average concentrations were calculated using five different methods: 1) inverse distance weighting of observation data alone, 2) raw CMAQ results, 3) observation-fused CMAQ results, 4) population-averaged raw CMAQ results and 5) population-averaged fused CMAQ results. It shows that while O3 (as well as NOx) monitoring networks in the HRR regions are dense enough to provide consistent regional average exposure estimation based on monitoring data alone, PM2.5 observation sites (as well as monitors for CO, SO2, PM10 and PM2.5 components) are usually sparse and the difference between the average concentrations estimated by the inverse distance interpolated observations, raw CMAQ and fused CMAQ results can be significantly different. Population-weighted average should be used to account spatial variation in pollutant concentration and population density. Using raw CMAQ results or observations alone might lead to significant biases in health outcome analyses. PMID:24747248

  20. When Are Radiative Corrections Important in the Minimal Supersymmetric Model?

    OpenAIRE

    Haber, Howard E.

    1993-01-01

    Precision electroweak measurements at LEP currently check the validity of the Standard Model to about one part in a thousand. Any successful model of physics beyond the Standard Model must be consistent with these observations. The impact of radiative corrections on the Minimal Supersymmetric Model (MSSM) is considered. The influence of supersymmetric particles on precision electroweak measurements is generally negligible since radiative corrections mediated by supersymmetric particles are su...

  1. Modelling of air resistance during drying of wood-chips

    OpenAIRE

    Karaj, S.; Barfuss, Isabel; Schalk, J.; Reisinger, G.; Pude, R.; Müller, Joachim

    2011-01-01

    The objective of this study was to investigate the parameters that affect the drying process of wood chips at low air flow conditions. This objective was determined by measuring the air pressure resistance being produced by wood chips by examining different variables such as: air flow rate, air velocity, wood chip size, bulk density, bulk height and porosity. The air flow resistance was measured inside a 3 meter high cylindrical air duct constructed at University of Hohenheim. Physical proper...

  2. A NEW COMBINED LOCAL AND NON-LOCAL PBL MODEL FOR METEOROLOGY AND AIR QUALITY MODELING

    Science.gov (United States)

    A new version of the Asymmetric Convective Model (ACM) has been developed to describe sub-grid vertical turbulent transport in both meteorology models and air quality models. The new version (ACM2) combines the non-local convective mixing of the original ACM with local eddy diff...

  3. Prediction of Indoor Air Exposure from Outdoor Air Quality Using an Artificial Neural Network Model for Inner City Commercial Buildings

    Directory of Open Access Journals (Sweden)

    Avril Challoner

    2015-12-01

    Full Text Available NO2 and particulate matter are the air pollutants of most concern in Ireland, with possible links to the higher respiratory and cardiovascular mortality and morbidity rates found in the country compared to the rest of Europe. Currently, air quality limits in Europe only cover outdoor environments yet the quality of indoor air is an essential determinant of a person’s well-being, especially since the average person spends more than 90% of their time indoors. The modelling conducted in this research aims to provide a framework for epidemiological studies by the use of publically available data from fixed outdoor monitoring stations to predict indoor air quality more accurately. Predictions are made using two modelling techniques, the Personal-exposure Activity Location Model (PALM, to predict outdoor air quality at a particular building, and Artificial Neural Networks, to model the indoor/outdoor relationship of the building. This joint approach has been used to predict indoor air concentrations for three inner city commercial buildings in Dublin, where parallel indoor and outdoor diurnal monitoring had been carried out on site. This modelling methodology has been shown to provide reasonable predictions of average NO2 indoor air quality compared to the monitored data, but did not perform well in the prediction of indoor PM2.5 concentrations. Hence, this approach could be used to determine NO2 exposures more rigorously of those who work and/or live in the city centre, which can then be linked to potential health impacts.

  4. Evaluation of air pollution modelling tools as environmental engineering courseware.

    Science.gov (United States)

    Souto González, J A; Bello Bugallo, P M; Casares Long, J J

    2004-01-01

    The study of phenomena related to the dispersion of pollutants usually takes advantage of the use of mathematical models based on the description of the different processes involved. This educational approach is especially important in air pollution dispersion, when the processes follow a non-linear behaviour so it is difficult to understand the relationships between inputs and outputs, and in a 3D context where it becomes hard to analyze alphanumeric results. In this work, three different software tools, as computer solvers for typical air pollution dispersion phenomena, are presented. Each software tool developed to be implemented on PCs, follows approaches that represent three generations of programming languages (Fortran 77, VisualBasic and Java), applied over three different environments: MS-DOS, MS-Windows and the world wide web. The software tools were tested by students of environmental engineering (undergraduate) and chemical engineering (postgraduate), in order to evaluate the ability of these software tools to improve both theoretical and practical knowledge of the air pollution dispersion problem, and the impact of the different environment in the learning process in terms of content, ease of use and visualization of results. PMID:15193095

  5. Dispersion model computations of urban air pollution in Espoo, Finland

    Energy Technology Data Exchange (ETDEWEB)

    Valkonen, E.; Haerkoenen, J.; Kukkonen, J.; Rantakrans, E.; Jalkanen, L.

    1997-12-31

    This report presents the numerical results of air quality studies of the city of Espoo in southern Finland. This city is one of the four cities in the Helsinki metropolitan area, having a total population of 850 000. A thorough emission inventory was made of both mobile and stationary sources in the Helsinki metropolitan area. The atmospheric dispersion was evaluated using an urban dispersion modelling system, including a Gaussian multiple-source plume model and a meteorological pre-processing model. The hourly time series of CO, NO{sub 2} and SO{sub 2} concentrations were predicted, using the emissions and meteorological data for the year 1990. The predicted results show a clear decrease in the yearly mean concentrations from southeast to northwest. This is due in part to the denser traffic in the southern parts of Espoo, and in part to pollution from the neighbouring cities of Helsinki and Vantaa, located east of Espoo. The statistical concentration parameters found for Espoo were lower than the old national air quality guidelines (1984); however, some occurrences of above-threshold values were found for NO{sub 2} in terms of the new guidelines (1996). The contribution of traffic to the total concentrations varies spatially from 30 to 90 % for NO{sub 2} from 1 to 65 % for SO{sub 2} while for CO it is nearly 100 %. The concentrations database will be further utilised to analyse the influence of urban air pollution on the health of children attending selected day nurseries in Espoo. The results of this study can also be applied in traffic and city planning. In future work the results will also be compared with data from the urban measurement network of the Helsinki Metropolitan Area Council. (orig.) 19 refs.

  6. Air temperature, radiation budget and area changes of Quisoquipina glacier in the Cordillera Vilcanota (Peru)

    Science.gov (United States)

    Suarez, Wilson; Macedo, Nicols; Montoya, Nilton; Arias, Sandro; Schauwecker, Simone; Huggel, Christian; Rohrer, Mario; Condom, Thomas

    2015-04-01

    The Peruvian Andes host about 71% of all tropical glaciers. Although several studies have focused on glaciers of the largest glaciered mountain range (Cordillera Blanca), other regions have received little attention to date. In 2011, a new program has been initiated with the aim of monitoring glaciers in the centre and south of Peru. The monitoring program is managed by the Servicio Nacional de Meteorologa e Hidrologa del Per (SENAMHI) and it is a joint project together with the Universidad San Antonio Abad de Cusco (UNSAAC) and the Autoridad Nacional del Agua (ANA). In Southern Peru, the Quisoquipina glacier has been selected due to its representativeness for glaciers in the Cordillera Vilcanota considering area, length and orientation. The Cordillera Vilcanota is the second largest mountain range in Peru with a glaciated area of approximately 279 km2 in 2009. Melt water from glaciers in this region is partly used for hydropower in the dry season and for animal breeding during the entire year. Using Landsat 5 images, we could estimate that the area of Quisoquipina glacier has decreased by approximately 11% from 3.66 km2 in 1990 to 3.26 km2 in 2010. This strong decrease is comparable to observations of other tropical glaciers. In 2011, a meteorological station has been installed on the glacier at 5180 m asl., measuring air temperature, wind speed, relative humidity, net short and longwave radiation and atmospheric pressure. Here, we present a first analysis of air temperature and the radiation budget at the Quisoquipina glacier for the first three years of measurements. Additionally, we compare the results from Quisoquipina glacier to results obtained by the Institut de recherche pour le dveloppement (IRD) for Zongo glacier (Bolivia) and Antizana glacier (Ecuador). For both, Quisoquipina and Zongo glacier, net shortwave radiation may be the most important energy source, thus indicating the important role of albedo in the energy balance of the glacier surface. This indicates the importance of understanding the role of snow cover in ablation processes of tropical glaciers.

  7. Environmental Radiation Effects on Mammals A Dynamical Modeling Approach

    CERN Document Server

    Smirnova, Olga A

    2010-01-01

    This text is devoted to the theoretical studies of radiation effects on mammals. It uses the framework of developed deterministic mathematical models to investigate the effects of both acute and chronic irradiation in a wide range of doses and dose rates on vital body systems including hematopoiesis, small intestine and humoral immunity, as well as on the development of autoimmune diseases. Thus, these models can contribute to the development of the system and quantitative approaches in radiation biology and ecology. This text is also of practical use. Its modeling studies of the dynamics of granulocytopoiesis and thrombocytopoiesis in humans testify to the efficiency of employment of the developed models in the investigation and prediction of radiation effects on these hematopoietic lines. These models, as well as the properly identified models of other vital body systems, could provide a better understanding of the radiation risks to health. The modeling predictions will enable the implementation of more ef...

  8. Subgrid-scale model for radiative transfer in turbulent participating media

    Energy Technology Data Exchange (ETDEWEB)

    Soucasse, L.; Rivire, Ph. [CNRS, UPR 288, Laboratoire EM2C, Grande Voie des Vignes, F-92290 Chtenay-Malabry (France); cole Centrale Paris, Grande Voie des Vignes, F-92290 Chtenay-Malabry (France); Soufiani, A., E-mail: anouar.soufiani@em2c.ecp.fr [CNRS, UPR 288, Laboratoire EM2C, Grande Voie des Vignes, F-92290 Chtenay-Malabry (France); cole Centrale Paris, Grande Voie des Vignes, F-92290 Chtenay-Malabry (France)

    2014-01-15

    The simulation of turbulent flows of radiating gases, taking into account all turbulence length scales with an accurate radiation transport solver, is computationally prohibitive for high Reynolds or Rayleigh numbers. This is particularly the case when the small structures are not optically thin. We develop in this paper a radiative transfer subgrid model suitable for the coupling with direct numerical simulations of turbulent radiating fluid flows. Owing to the linearity of the Radiative Transfer Equation (RTE), the emission source term is spatially filtered to define large-scale and subgrid-scale radiation intensities. The large-scale or filtered intensity is computed with a standard ray tracing method on a coarse grid, and the subgrid intensity is obtained analytically (in Fourier space) from the Fourier transform of the subgrid emission source term. A huge saving of computational time is obtained in comparison with direct ray tracing applied on the fine mesh. Model accuracy is checked for three 3D fluctuating temperature fields. The first field is stochastically generated and allows us to discuss the effects of the filtering level and of the optical thicknesses of the whole medium, of the integral length scale, and of the cutoff wave length. The second and third cases correspond respectively to turbulent natural convection of humid air in a cubical box, and to the flow of hot combustion products inside a channel. In all cases, the achieved accuracy on radiative powers and wall fluxes is about a few percents.

  9. Surface air temperature variability in global climate models

    OpenAIRE

    Davy, Richard; Esau, Igor

    2013-01-01

    New results from the Coupled Model Inter-comparison Project phase 5 (CMIP5) and multiple global reanalysis datasets are used to investigate the relationship between the mean and standard deviation in the surface air temperature. A combination of a land-sea mask and orographic filter were used to investigate the geographic region with the strongest correlation and in all cases this was found to be for low-lying over-land locations. This result is consistent with the expectation that difference...

  10. NASA Air Force Cost Model (NAFCOM): Capabilities and Results

    Science.gov (United States)

    McAfee, Julie; Culver, George; Naderi, Mahmoud

    2011-01-01

    NAFCOM is a parametric estimating tool for space hardware. Uses cost estimating relationships (CERs) which correlate historical costs to mission characteristics to predict new project costs. It is based on historical NASA and Air Force space projects. It is intended to be used in the very early phases of a development project. NAFCOM can be used at the subsystem or component levels and estimates development and production costs. NAFCOM is applicable to various types of missions (crewed spacecraft, uncrewed spacecraft, and launch vehicles). There are two versions of the model: a government version that is restricted and a contractor releasable version.

  11. Quantifying urban street configuration for improvements in air pollution models

    Science.gov (United States)

    Eeftens, Marloes; Beekhuizen, Johan; Beelen, Rob; Wang, Meng; Vermeulen, Roel; Brunekreef, Bert; Huss, Anke; Hoek, Gerard

    2013-06-01

    In many built-up urban areas, tall buildings along narrow streets obstruct the free flow of air, resulting in higher pollution levels. Input data to account for street configuration in models are difficult to obtain for large numbers of streets. We describe an approach to calculate indicators of this "urban canyon effect" using 3-dimensional building data and evaluated whether these indicators improved spatially resolved land use regression (LUR) models.Concentrations of NO2 and NOx were available from 132 sites in the Netherlands. We calculated four indicators for canyon effects at each site: (1) the maximum aspect ratio (building height/width of the street) between buildings on opposite sides of the street, (2) the mean building angle, which is the angle between the horizontal street level and the line of sight to the top of surrounding buildings, (3) median building angle and (4) "SkyView Factor" (SVF), a measure of the total fraction of visible sky. Basic LUR models were computed for both pollutants using common predictors such as household density, land-use and nearby traffic intensity. We added each of the four canyon indicators to the basic LUR models and evaluated whether they improved the model.The calculated aspect ratio agreed well (R2 = 0.49) with aspect ratios calculated from field observations. Explained variance (R2) of the basic LUR models without canyon indicators was 80% for NO2 and 76% for NOx, and increased to 82% and 78% respectively if SVF was included. Despite this small increase in R2, contrasts in SVF (10th-90th percentile) resulted in substantial concentration differences of 5.56 ?g m-3 in NO2 and 10.9 ?g m-3 in NOx.We demonstrated a GIS based approach to quantify the obstruction of free air flow by buildings, applicable for large numbers of streets. Canyon indicators could be valuable to consider in air pollution models, especially in areas with low- and high-rise canyons.

  12. Spatial and energy distributions of skyshine neutron and gamma radiation from nuclear reactors on the ground-air boundary

    International Nuclear Information System (INIS)

    A set of measurements on skyshine radiation was conducted at two special research reactors. A broad range of detectors was used in the measurements to record neutron and gamma radiations. Dosimetric and radiometric field measurements of the neutrons and gamma quanta of the radiation scattered in the air were performed at distances of 50 to 1000 m from the reactor during different weather conditions. The neutron spectra in the energy range of 1 eV to 10 MeV and the gamma quanta spectra in the range of 0.1-10 MeV were measured. (author)

  13. Quality criteria for air pollution models, standardisation and model development in the Netherlands

    International Nuclear Information System (INIS)

    Based on standards of EPA and IEEE, quality criteria have been formulated which address the development of air pollution models, the transformation towards user-friendly software and ''after-sales'' service. A Dutch standard on the description of air pollution models is being finalized. The standard formulates minimal requirements on the theoretical and practical description of models. This paper provides a survey of the quality criteria and it summarizes the standard. Further, the current practice of model development at RIVM is discussed. (au) (24 refs.)

  14. New calculation method for thermodynamic properties of humid air in humid air turbine cycle – The general model and solutions for saturated humid air

    International Nuclear Information System (INIS)

    The article proposes a new calculation method for thermodynamic properties (i.e. specific enthalpy, specific entropy and specific volume) of humid air in humid air turbine cycle. The research pressure range is from 0.1 MPa to 5 MPa. The fundamental behaviors of dry air and water vapor in saturated humid air are explored in depth. The new model proposes and verifies the relationship between total gas mixture pressure and gas component pressures. This provides a good explanation of the fundamental behaviors of gas components in gas mixture from a new perspective. Another discovery is that the water vapor component pressure of saturated humid air equals PS, always smaller than its partial pressure (f·PS) which was believed in the past researches. In the new model, “Local Gas Constant” describes the interaction between similar molecules. “Improvement Factor” is proposed for the first time by this article, and it quantitatively describes the magnitude of interaction between dissimilar molecules. They are combined to fully describe the real thermodynamic properties of humid air. The average error of Revised Dalton's Method is within 0.1% compared to experimentally-based data. - Highlights: • Our new model is suitable to calculate thermodynamic properties of humid air in HAT cycle. • Fundamental behaviors of dry air and water vapor in saturated humid air are explored in depth. • Local-Gas-Constant describes existing alone component and Improvement Factor describes interaction between different components. • The new model proposes and verifies the relationship between total gas mixture pressure and component pressures. • It solves saturated humid air thoroughly and deviates from experimental data less than 0.1%

  15. Radiation exposure modeling and project schedule visualization

    International Nuclear Information System (INIS)

    This paper discusses two applications using IGRIP (Interactive Graphical Robot Instruction Program) to assist environmental remediation efforts at the Department of Energy (DOE) Hanford Site. In the first application, IGRIP is used to calculate the estimated radiation exposure to workers conducting tasks in radiation environments. In the second, IGRIP is used as a configuration management tool to detect interferences between equipment and personnel work areas for multiple projects occurring simultaneously in one area. Both of these applications have the capability to reduce environmental remediation costs by reducing personnel radiation exposure and by providing a method to effectively manage multiple projects in a single facility

  16. A kinetic model of radiating electrons

    International Nuclear Information System (INIS)

    A kinetic theory is developed to describe radiating electrons whose motion is governed by the Lorentz-Dirac equation. This gives rise to a generalized Vlasov equation coupled to an equation for the evolution of the physical submanifold of phase space. The pathological solutions of the 1-particle theory may be removed by expanding the latter equation in powers of τ:=q2/6πm. The radiation-induced change in entropy is explored and its physical origin is discussed. As a simple demonstration of the theory, the radiative damping rate of longitudinal plasma waves is calculated.

  17. Modelling air pollution abatement in deep street canyons by means of air scrubbers

    OpenAIRE

    De Giovanni, Marina; Curci, Gabriele; Avveduto, Alessandro; Pace, Lorenzo; Salisburgo, Cesare Dari; Giammaria, Franco; Monaco, Alessio; Spanto, Giuseppe; Tripodi, Paolo

    2015-01-01

    Deep street canyons are characterized by weak ventilation and recirculation of air. In such environment, the exposure to particulate matter and other air pollutants is enhanced, with a consequent worsening of both safety and health. The main solution adopted by the international community is aimed at the reduction of the emissions. In this theoretical study, we test a new solution: the removal of air pollutants close to their sources by a network of Air Pollution Abatement (APA) devices. The ...

  18. Validation of the Poisson Stochastic Radiative Transfer Model

    Science.gov (United States)

    Zhuravleva, Tatiana; Marshak, Alexander

    2004-01-01

    A new approach to validation of the Poisson stochastic radiative transfer method is proposed. In contrast to other validations of stochastic models, the main parameter of the Poisson model responsible for cloud geometrical structure - cloud aspect ratio - is determined entirely by matching measurements and calculations of the direct solar radiation. If the measurements of the direct solar radiation is unavailable, it was shown that there is a range of the aspect ratios that allows the stochastic model to accurately approximate the average measurements of surface downward and cloud top upward fluxes. Realizations of the fractionally integrated cascade model are taken as a prototype of real measurements.

  19. Modelling radiative heat transfer inside a basin type solar still

    International Nuclear Information System (INIS)

    Radiative heat transfer inside a basin type solar still has been investigated using two models with (model 1) and without (model 2) taking into account optical view factors. The coefficient of radiative heat exchange (hr,w-gc) between the water and cover surfaces of a practical solar still was computed using the two models. Simulation results show that model 1 yields lower values of hr,w-gc and the root mean square error than model 2. It is therefore concluded that the accuracy of modelling the performance of a basin-type solar still can be improved by incorporating view factors. - Highlights: • Radiative heat transfer in a basin type solar still has been investigated. • Two models with and without view factors were used. • The model with view factors exhibits a lower magnitude of root mean square error. • View factors affect the accuracy of modelling the performance of the solar still

  20. Application of zonal model on indoor air sensor network design

    Science.gov (United States)

    Chen, Y. Lisa; Wen, Jin

    2007-04-01

    Growing concerns over the safety of the indoor environment have made the use of sensors ubiquitous. Sensors that detect chemical and biological warfare agents can offer early warning of dangerous contaminants. However, current sensor system design is more informed by intuition and experience rather by systematic design. To develop a sensor system design methodology, a proper indoor airflow modeling approach is needed. Various indoor airflow modeling techniques, from complicated computational fluid dynamics approaches to simplified multi-zone approaches, exist in the literature. In this study, the effects of two airflow modeling techniques, multi-zone modeling technique and zonal modeling technique, on indoor air protection sensor system design are discussed. Common building attack scenarios, using a typical CBW agent, are simulated. Both multi-zone and zonal models are used to predict airflows and contaminant dispersion. Genetic Algorithm is then applied to optimize the sensor location and quantity. Differences in the sensor system design resulting from the two airflow models are discussed for a typical office environment and a large hall environment.

  1. Modeling Air Traffic Management Technologies with a Queuing Network Model of the National Airspace System

    Science.gov (United States)

    Long, Dou; Lee, David; Johnson, Jesse; Gaier, Eric; Kostiuk, Peter

    1999-01-01

    This report describes an integrated model of air traffic management (ATM) tools under development in two National Aeronautics and Space Administration (NASA) programs -Terminal Area Productivity (TAP) and Advanced Air Transport Technologies (AATT). The model is made by adjusting parameters of LMINET, a queuing network model of the National Airspace System (NAS), which the Logistics Management Institute (LMI) developed for NASA. Operating LMINET with models of various combinations of TAP and AATT will give quantitative information about the effects of the tools on operations of the NAS. The costs of delays under different scenarios are calculated. An extension of Air Carrier Investment Model (ACIM) under ASAC developed by the Institute for NASA maps the technologies' impacts on NASA operations into cross-comparable benefits estimates for technologies and sets of technologies.

  2. User's guide to the LIRAQ model: an air pollution model for the San Francisco Bay Area

    International Nuclear Information System (INIS)

    The Livermore Regional Air Quality (LIRAQ) model comprises a set of computer programs that have been integrated into an easily used tool for the air quality planner. To assemble and modify the necessary data files and to direct model execution, a problem formulation program has been developed that makes possible the setup of a wide variety of studies involving perturbation of the emission inventory, changes to the initial and boundary conditions, and different choices of grid size and problem domain. In addition to describing the types of air quality problems for which the LIRAQ model may be used, this User's Guide provides detailed information on how to set up and conduct model simulations. Also included are descriptions of the formats of input data files so that the LIRAQ model may be applied to regions other than the San Francisco Bay Area

  3. Health risks maps. Modelling of air quality as a tool to map health risks

    International Nuclear Information System (INIS)

    Environmental departments consider geographical maps with information on air quality as the final product of a complicated process of measuring, modelling and presentation. Municipal health departments consider such maps a useful starting point to solve the problem whether air pollution causes health risks for citizens. The answer to this question cannot be reduced to checking if threshold limit values are exceeded. Based on the results of measurements and modelling of concentrations of nitrogen dioxide in air, the health significance of air pollution caused by nitrogen dioxide is illuminated. A proposal is presented to map health risks of air pollution by using the results of measurements and modelling of air pollution. 7 refs

  4. Measurement and modeling of external radiation during 1984 from LAMPF atmospheric emissions

    International Nuclear Information System (INIS)

    An array of three portable, pressurized ionization chambers (PICs) measured short-term external radiation levels produced by air activation products from the Los Alamos Meson Physics Facility (LAMPF). The monitoring was at the closet offsite location, 700-900 m north and northeast of the source, and across a large, deep canyon. A Gaussian-type atmospheric dispersion model, using onsite meteorological and stack release data, was tested during their study. Monitoring results indicate that a persistent, local up-valley wind during the evening and early morning hours is largely responsible for causing the highest radiation levels to the northeast and north-northeast of LAMPF. Comparison of predicted and measured daily external radiation levels indicates a high degree of correlation. The model also gives accurate estimates of measured concentrations over longer periods of time

  5. An optimization model for the US Air-Traffic System

    Science.gov (United States)

    Mulvey, J. M.

    1986-01-01

    A systematic approach for monitoring U.S. air traffic was developed in the context of system-wide planning and control. Towards this end, a network optimization model with nonlinear objectives was chosen as the central element in the planning/control system. The network representation was selected because: (1) it provides a comprehensive structure for depicting essential aspects of the air traffic system, (2) it can be solved efficiently for large scale problems, and (3) the design can be easily communicated to non-technical users through computer graphics. Briefly, the network planning models consider the flow of traffic through a graph as the basic structure. Nodes depict locations and time periods for either individual planes or for aggregated groups of airplanes. Arcs define variables as actual airplanes flying through space or as delays across time periods. As such, a special case of the network can be used to model the so called flow control problem. Due to the large number of interacting variables and the difficulty in subdividing the problem into relatively independent subproblems, an integrated model was designed which will depict the entire high level (above 29000 feet) jet route system for the 48 contiguous states in the U.S. As a first step in demonstrating the concept's feasibility a nonlinear risk/cost model was developed for the Indianapolis Airspace. The nonlinear network program --NLPNETG-- was employed in solving the resulting test cases. This optimization program uses the Truncated-Newton method (quadratic approximation) for determining the search direction at each iteration in the nonlinear algorithm. It was shown that aircraft could be re-routed in an optimal fashion whenever traffic congestion increased beyond an acceptable level, as measured by the nonlinear risk function.

  6. Modeling Clinical Radiation Responses in the IMRT Era

    Science.gov (United States)

    Schwartz, J. L.; Murray, D.; Stewart, R. D.; Phillips, M. H.

    2014-03-01

    The purpose of this review is to highlight the critical issues of radiobiological models, particularly as they apply to clinical radiation therapy. Developing models of radiation responses has a long history that continues to the present time. Many different models have been proposed, but in the field of radiation oncology, the linear-quadratic (LQ) model has had the most impact on the design of treatment protocols. Questions have been raised as to the value of the LQ model given that the biological assumption underlying it has been challenged by molecular analyses of cell and tissue responses to radiation. There are also questions as to use of the LQ model for hypofractionation, especially for high dose treatments using a single fraction. While the LQ model might over-estimate the effects of large radiation dose fractions, there is insufficient information to fully justify the adoption of alternative models. However, there is increasing evidence in the literature that non-targeted and other indirect effects of radiation sometimes produce substantial deviations from LQ-like dose-response curves. As preclinical and clinical hypofractionation studies accumulate, new or refined dose-response models that incorporate high-dose/fraction non-targeted and indirect effects may be required, but for now the LQ model remains a simple, useful tool to guide the design of treatment protocols.

  7. A Model of Radiation Damage in Graphite

    International Nuclear Information System (INIS)

    Hennig and Hove proposed a model of radiation damage to graphite at the first Geneva Conference and attributed the so-called Wigner-energy release around 200C to the reaction of single interstitials forming C2 molecules. We propose a new model as follows: (1) Single interstitial atoms migrate easily far below liquid-nitrogen temperature. They gather to mak clusters (atomic clusters) where each atom hs about a 10-A separation. This distance is shown to be elastically stable. (2) C2 molecules (partially C3 molecules) are formed from atomic clusters between 80K and 110K. The reverse annealing of electrical resistivity in this temperature range is explained with the aid of electronic band structure. (3) C2 molecules migrate and form the clusters consisting of molecules (molecular clusters) above 160K. Larger clusters are made at higher temperatures. Each molecule in the clusters is held together by bonds which are much weaker than ordinary covalent bonds and by the elastic forces due to strained layers. (4) Molecular clusters may decompose to constituent molecules around 200C and above. C2 molecules then recombine with vacancies or escape to surfaces, causing energy release. The striking energy release around 200C is caused by the disappearance of C2-C2 molecular clusters. As the temperature is raised, these clusters are further decomposed. Its decomposition is completed below 1000C. (5) When molecular clusters become large (the number of constituent atoms > about 10), they can be transformed co-operatively to hexagonal covalent-bonded clusters as graphite layers by externally supplied energy. Further, at the region heavily strained by large clusters, some intra-layer covalent bonds are cut by energetic particles and the new covalent bonds are formed between the clusters and the unpaired atoms in the layers. This coupling explains the sudden broadening of X-ray line profiles and the abrupt change in stored- energy release and electrical resistivity recovery found above doses of 6 x 1020 n/cm2. (6) The hexagonal covalent-bonded clusters do not disappear until irradiation-induced vacancies begin to migrate and recombine with them. The disappearance probably starts above 1000C. (author)

  8. Some critical remarks about the radiative heat transfer in air frame cavities according to EN ISO 10077-2

    Science.gov (United States)

    Cuccurullo, G.; Giordano, L.

    2015-11-01

    Thermal performances of windows frames are established, in Europe, by the international standard UNI EN ISO 10077-2:2012. The standard introduces an equivalent thermal conductivity for air frame cavities thus simplifying the original combined heat transfer problem to a merely two-dimensional conductive one. The equivalence is referred to a rectangular cavity and is not able to fully recover the same radiative heat flux involved in the original problem. In view of that, the paper is focused on the radiative heat transfer taking place in the air cavities and aims to check if different equivalence criteria could lead to improved results. Thus, numerical tests involving an accurate description of radiative heat transfer in air cavities are compared to the simplified fully-conductive one provided by the standard. Results show that different criteria lead to quite different results. The optimal criterion turns out to depend on both geometrical and surface radiative parameters. It is also shown that, in any case, a proper radiative resistance but not the one suggested by the ISO 10077 should be adopted.

  9. Observations of surface radiation and stratospheric processes at Thule Air Base, Greenland, during the IPY

    Directory of Open Access Journals (Sweden)

    Giovanni Muscari

    2014-06-01

    Full Text Available Ground-based measurements of atmospheric parameters have been carried out for more than 20 years at the Network for the Detection of Atmospheric Composition Change (NDACC station at Thule Air Base (76.5N, 68.8W, on the north-western coast of Greenland. Various instruments dedicated to the study of the lower and middle polar atmosphere are installed at Thule in the framework of a long standing collaboration among Danish, Italian, and US research institutes and universities. This effort aims at monitoring the composition, structure and dynamics of the polar stratosphere, and at studying the Arctic energy budget and the role played by different factors, such as aerosols, water vapour, and surface albedo. During the International Polar Year (IPY, in winter 2008-2009, an intensive measurement campaign was conducted at Thule within the framework of the IPY project Ozone layer and UV radiation in a changing climate evaluated during IPY (ORACLE-O3 which sought to improve our understanding of the complex mechanisms that lead to the Arctic stratospheric O3 depletion. The campaign involved a lidar system, measuring aerosol backscatter and depolarization ratios up to 35 km and atmospheric temperature profiles from 25 to 70 km altitude, a ground-based millimeter-wave spectrometer (GBMS used to derive stratospheric mixing ratio profiles of different chemical species involved in the stratospheric ozone depletion cycle, and then ground-based radiometers and a Cimel sunphotometer to study the Arctic radiative budget at the surface. The observations show that the surface radiation budget is mainly regulated by the longwave component throughout most of the year. Clouds have a significant impact contributing to enhance the role of longwave radiation. Besides clouds, water vapour seasonal changes produce the largest modification in the shortwave component at the surface, followed by changes in surface albedo and in aerosol amounts. For what concerns the middle atmosphere, during the first part of winter 2008-2009 the cold polar vortex allowed for the formation of polar stratospheric clouds (PSCs which were observed above Thule by means of the lidar. This period was also characterized by GBMS measurements of low values of O3 due to the catalytic reactions prompted by the PSCs. In mid-January, as the most intense Sudden Stratospheric Warming event ever observed in the Arctic occurred, GBMS and lidar measurements of O3, N2O, CO and temperature described its evolution as it propagated from the upper atmosphere to the lower stratosphere.

  10. Treatment of cloud radiative effects in general circulation models

    Energy Technology Data Exchange (ETDEWEB)

    Wang, W.C.; Dudek, M.P.; Liang, X.Z.; Ding, M. [State Univ. of New York, Albany, NY (United States)] [and others

    1996-04-01

    We participate in the Atmospheric Radiation Measurement (ARM) program with two objectives: (1) to improve the general circulation model (GCM) cloud/radiation treatment with a focus on cloud verticle overlapping and layer cloud optical properties, and (2) to study the effects of cloud/radiation-climate interaction on GCM climate simulations. This report summarizes the project progress since the Fourth ARM Science Team meeting February 28-March 4, 1994, in Charleston, South Carolina.

  11. The radiation budget in a regional climate model

    OpenAIRE

    Kothe, Steffen

    2012-01-01

    The aim of this study is a better understanding of radiation processes in regional climate models (RCMs) in order to quantify their impact and to reduce possible errors. A first important task in finding an answer to this question was to examine the accuracy of the components of the radiation budget in regional climate simulations. To this end, the simulated radiation budgets of two regional climate simulations for Europe were compared with a satellite-based reference. In the simulations with...

  12. Verification of SpacePy's radial diffusion radiation belt model

    OpenAIRE

    D. T. Welling; J. Koller; E. Camporeale

    2011-01-01

    Model verification, or the process of ensuring that the prescribed equations are properly solved, is a necessary step in code development. Careful, quantitative verification guides users when selecting grid resolution and time step and gives confidence to code developers that existing code is properly instituted. This work introduces the RadBelt radiation belt model, a new, open-source version of the Dynamic Radiation Environment Assimilation Model (DREAM) and uses the Method of Manufactured ...

  13. Stochastic radiative transfer model for mixture of discontinuous vegetation canopies

    Energy Technology Data Exchange (ETDEWEB)

    Shabanov, Nikolay V. [Department of Geography, Boston University, 675 Commonwealth Avenue, Boston, MA 02215 (United States)]. E-mail: shabanov@bu.edu; Huang, D. [Brookhaven National Laboratory, Environmental Sciences Department, P.O. Box 5000, Upton, NY 11973 (United States); Knjazikhin, Y. [Department of Geography, Boston University, 675 Commonwealth Avenue, Boston, MA 02215 (United States); Dickinson, R.E. [School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Myneni, Ranga B. [Department of Geography, Boston University, 675 Commonwealth Avenue, Boston, MA 02215 (United States)

    2007-09-15

    Modeling of the radiation regime of a mixture of vegetation species is a fundamental problem of the Earth's land remote sensing and climate applications. The major existing approaches, including the linear mixture model and the turbid medium (TM) mixture radiative transfer model, provide only an approximate solution to this problem. In this study, we developed the stochastic mixture radiative transfer (SMRT) model, a mathematically exact tool to evaluate radiation regime in a natural canopy with spatially varying optical properties, that is, canopy, which exhibits a structured mixture of vegetation species and gaps. The model solves for the radiation quantities, direct input to the remote sensing/climate applications: mean radiation fluxes over whole mixture and over individual species. The canopy structure is parameterized in the SMRT model in terms of two stochastic moments: the probability of finding species and the conditional pair-correlation of species. The second moment is responsible for the 3D radiation effects, namely, radiation streaming through gaps without interaction with vegetation and variation of the radiation fluxes between different species. We performed analytical and numerical analysis of the radiation effects, simulated with the SMRT model for the three cases of canopy structure: (a) non-ordered mixture of species and gaps (TM); (b) ordered mixture of species without gaps; and (c) ordered mixture of species with gaps. The analysis indicates that the variation of radiation fluxes between different species is proportional to the variation of species optical properties (leaf albedo, density of foliage, etc.) Gaps introduce significant disturbance to the radiation regime in the canopy as their optical properties constitute major contrast to those of any vegetation species. The SMRT model resolves deficiencies of the major existing mixture models: ignorance of species radiation coupling via multiple scattering of photons (the linear mixture model) or overestimation of this coupling due to neglecting spatial clumping of species (the TM approach). Thus, based on the former experience with mixture modeling, this study establishes an advanced theoretical basis for future mixture applications.

  14. Effect of surface radiation on the breakdown of steady natural convection flows in a square, air-filled cavity containing a centered inner body

    International Nuclear Information System (INIS)

    The physical model considered in the present numerical work is a square air-filled cavity cooled from below and above, with a heated square body located at the cavity center. The aim is to establish the effects of radiation interchanges amongst surfaces on the transition from steady, symmetric flows about the cavity centerline to complex periodic flows. Owing to the low temperature differences involved (1 K ≤ ΔT ≤ 5 K), the two-dimensional model is based on the Boussinesq approximation and constant thermophysical fluid properties at room temperature. The cavity walls are assumed gray and diffuse. The flow structure is investigated for various Rayleigh numbers, emissivities of the wall surfaces and sizes of the inner body. The results clearly establish the influence of surface radiation, both for steady and unsteady flows. For the geometry and thermal boundary conditions considered, the Rayleigh number for the transition to unsteady flows is considerably increased under the influence of radiation. This work underlines the difficulties in comparing experimental data and numerical solutions for gas-filled cavities partly subjected to wall heat flux boundary conditions. - Research highlights: → Heat transfer in cavities cooled from below and above with an inner heated body. → Effects of radiation on the transitions to unsteady flows are numerically studied. → The surfaces are gray and diffuse and the temperature differences are from 1 K to 5 K. → Critical Rayleigh numbers are considerably increased by radiation. → According to the thermal boundary conditions, combined analyses are required.

  15. CFD Modeling of Air Pocket Transport in Conjunction with Spillway Conduits

    OpenAIRE

    Liu, Ting; Yang, James

    2011-01-01

    This paper focuses on simulations of enclosed air pocket movements in conjunction with bottom outlet operations. The critical velocity of water for air pocket transport in pipe is the minimal flow velocity for the air pocket start to move downstream. A numerical model is developed to simulate the critical velocity of air pocket transport in pipe flow and to discuss the impacts of tunnel slope, size of the air pocket and wall roughness. The computations are performed in FLUENT using Volume of ...

  16. Impacts and implementation of fuel moisture release and radiation properties in modelling of pulverized fuel combustion processes

    DEFF Research Database (Denmark)

    Yin, Chungen

    2015-01-01

    presents different methods for fuel moisture release and new models for gas and particle radiative properties, and demonstrates their implementation, importance and impacts in PF combustion modelling via a comprehensive CFD study of a pulverized coal-fired utility boiler. To conclude, it is recommended to...... add the free moisture into the primary air stream while lump the moisture retained in the feed after the mills with volatiles in PF combustion modelling. For gas and particle radiation in PF boilers, it is found that particle radiation largely overwhelms gas radiation due to high particle loading......Pulverized fuels (PF) prepared and fired in utility boilers usually contain a certain amount of moisture, either free moisture or chemically bound moisture. In PF furnaces, radiation which is the principal mode of heat transfer consists of contribution from both gas and particle phase. This paper...

  17. NASA Space Radiation Program Integrative Risk Model Toolkit

    Science.gov (United States)

    Kim, Myung-Hee Y.; Hu, Shaowen; Plante, Ianik; Ponomarev, Artem L.; Sandridge, Chris

    2015-01-01

    NASA Space Radiation Program Element scientists have been actively involved in development of an integrative risk models toolkit that includes models for acute radiation risk and organ dose projection (ARRBOD), NASA space radiation cancer risk projection (NSCR), hemocyte dose estimation (HemoDose), GCR event-based risk model code (GERMcode), and relativistic ion tracks (RITRACKS), NASA radiation track image (NASARTI), and the On-Line Tool for the Assessment of Radiation in Space (OLTARIS). This session will introduce the components of the risk toolkit with opportunity for hands on demonstrations. The brief descriptions of each tools are: ARRBOD for Organ dose projection and acute radiation risk calculation from exposure to solar particle event; NSCR for Projection of cancer risk from exposure to space radiation; HemoDose for retrospective dose estimation by using multi-type blood cell counts; GERMcode for basic physical and biophysical properties for an ion beam, and biophysical and radiobiological properties for a beam transport to the target in the NASA Space Radiation Laboratory beam line; RITRACKS for simulation of heavy ion and delta-ray track structure, radiation chemistry, DNA structure and DNA damage at the molecular scale; NASARTI for modeling of the effects of space radiation on human cells and tissue by incorporating a physical model of tracks, cell nucleus, and DNA damage foci with image segmentation for the automated count; and OLTARIS, an integrated tool set utilizing HZETRN (High Charge and Energy Transport) intended to help scientists and engineers study the effects of space radiation on shielding materials, electronics, and biological systems.

  18. Air pollution modeling for an industrial complex and model performance evaluation

    International Nuclear Information System (INIS)

    Jamshedpur, the steel city of India situated in the eastern part of India is affected by increasing air pollution levels as a result of concentrated industrial activities. The impact of NOx emissions resulting from various air pollution sources, viz. industries, vehicles and domestic, was estimated using Industrial Source Complex Short-Term gaussian dispersion model. The contribution of NOx concentration from industrial, vehicular and domestic sources was found to be 53, 40 and 7%. Further statistical analysis was carried out to evaluate the model performance by comparing measured and predicted NOx concentrations. The model performance was found good with an accuracy of about 68%. (Author)

  19. Solar radiation modeling and measurements for renewable energy applications: data and model quality

    International Nuclear Information System (INIS)

    Measurement and modeling of broadband and spectral terrestrial solar radiation is important for the evaluation and deployment of solar renewable energy systems. We discuss recent developments in the calibration of broadband solar radiometric instrumentation and improving broadband solar radiation measurement accuracy. An improved diffuse sky reference and radiometer calibration and characterization software for outdoor pyranometer calibrations are outlined. Several broadband solar radiation model approaches, including some developed at the National Renewable Energy Laboratory, for estimating direct beam, total hemispherical and diffuse sky radiation are briefly reviewed. The latter include the Bird clear sky model for global, direct beam, and diffuse terrestrial solar radiation; the Direct Insolation Simulation Code (DISC) for estimating direct beam radiation from global measurements; and the METSTAT (Meteorological and Statistical) and Climatological Solar Radiation (CSR) models that estimate solar radiation from meteorological data. We conclude that currently the best model uncertainties are representative of the uncertainty in measured data

  20. Optical tomographic in-air scanner for external radiation beam 3D gel dosimetry

    International Nuclear Information System (INIS)

    Full text: Optical CT scanners are used to measure 3D radiation dose distributions in radiosensitive gels. For radiotherapy dose verification, 3D dose measurements are useful for verification of complex linear accelerator treatment planning and delivery techniques. Presently optical CTs require the use of a liquid bath to match the refractive index of the gel to minimise refraction of the light rays leading to distortion and artifacts. This work aims to develop a technique for scanning gel samples in free-air, without the requirement for a matching liquid bath. The scanner uses a He-Ne laser beam, fanned across the acrylic cylindrical gel container by a rotating mirror. The gel container was designed to produce parallel light ray paths through the gel. A pin phantom was used to quantify geometrical distortion of the reconstructed image, while uniform field exposures were used to consider noise, uniformity and artifacts. Small diameter wires provided an indication of the spatial resolution of the scanner. Pin phantom scans show geometrical distortion comparable to scanners using matching fluid baths. Noise, uniformity and artifacts were not found to be major limitations for this scanner approach. Spatial resolution was limited by laser beam spot size, typically 0.4 mm full width half maximum. A free-air optical CT scanner has been developed with the advantage of scanning without a matching fluid bath. Test results show it has potential to provide suitable quality 3D dosimetry measurements for external beam dose verification, while offering significant advantages in convenience and efficiency for routine use.