WorldWideScience

Sample records for radiation air model

  1. Models for obtaining daily global solar radiation with measured air temperature data in Madrid (Spain)

    International Nuclear Information System (INIS)

    Solar radiation is a primary driver for many physical, chemical and biological processes on the earth's surface. Complete and accurate solar radiation data at a specific region are quite indispensable to the solar energy related research. For locations where measured values are not available, a number of formulas and models have been developed to estimate solar radiation. This study aimed to calibrate seven existing models and develop one new model for estimating global solar radiation data using temperature measured data for seven stations located in Madrid, Spain. This work concludes that empirical models based on temperature give good results in any location if the parameters are correctly adjusted. A newly developed model that include the difference between maximum and minimum daily air temperature, and the saturation vapour pressures at temperature maximum and minimum, provided estimates with less error than other models. According to the results, the new model showed the best estimation for all stations and therefore is recommended. It is believed that the model developed in this work is applicable for estimating the daily global solar radiation on a horizontal surface at any site in Community of Madrid, Spain. The daily global solar radiation values produced by this approach can be used in the design and estimation of the performance of solar applications.

  2. 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.

  3. Collisional-radiative model in air for earth re-entry problems

    International Nuclear Information System (INIS)

    A nonlinear time-dependent two-temperature collisional-radiative model for air plasma has been developed for pressures between 1 kPa and atmospheric pressure to be applied to the flow conditions of space vehicle re-entry into the Earth's atmosphere. The model consists of 13 species: N2, O2, N, O, NO, N2+, O2+, N+, O+, NO+, O2-, O- in their ground state and major electronic excited states and of electrons. Many elementary processes are considered given the temperatures involved (up to 10 000 K). Time scales to reach the final nonequilibrium or equilibrium steady states are derived. Then we apply our model to two typical re-entry situations and show that O2- and O- play an important role during the ionization phase. Finally, a comparison with existing reduced kinetic mechanisms puts forward significant discrepancies for high velocity flows when the flow is in chemical nonequilibrium and smaller discrepancies when the flow is close to chemical equilibrium. This comparison illustrates the interest of using a time-dependent collisional-radiative model to validate reduced kinetic schemes for the relevant time scales of the flows studied

  4. Mixed radiation in air

    International Nuclear Information System (INIS)

    Five laboratories were selected to effect the irradiation of dosemeters under the European programme of intercomparison. Responsibility for 'mixed' radiation irradiation, the specification of which was defined at the meeting held in Luxembourg on 18-19 June 1981, was entrusted to the Service Technique d'Equipements de Protection et de Dosimetrie, Laboratoire d'Instrumentation et de Dosimetrie of the French Commissariat a l'Energie Atomique, at the Centre d'Etudes Nucleaires at Fontenay-aux-Roses (CEA-STEPD-LID, CENFAR). The irradiation equipment used forms part of the ionizing radiation calibration set at the French National Metrology Office, and the instruments are themselves calibrated against the national calibration standards maintained by the primary laboratory, the Laboratoire de Mesure des Rayonnements Ionisants (LMRI - CEA - SACLAY). Although the references for calibration of exposure to photon radiation beams used were themselves calibrated against the national calibration standards in the 'ionizing radiation' set, a direct intercomparison of these references has been made with the aid of an instrument in the possession of the RIV laboratory at Bilthoven. The results are described in another paper presented at this seminar, and those participating in the intercomparison should refer to it before drawing any definite conclusions about their own dosemeters. Range of X-ray energies and the required energy correction factor was obtained by interpolation. The stanor was obtained by interpolation. The standard temperature and pressure correction factors were, of course, applied. It is estimated that the overall accuracy on the exposure measurements at the 95% confidence limits is ± 2%. 62 dosemeters were exposed from 28 participants. Some establishments sent both TLD and film dosemeters while the majority sent either one type or the other

  5. The radiation length in air

    International Nuclear Information System (INIS)

    It is confirmed, in case of nitrogen, that the radiation length t0 calculated for a Thomas-Fermi distribution of the electron cloud is within 0.6% of the correct value, i.e. the value calculated using accurate self-consistent orbital wavefunctions (Wheeler and Lamb 1939). It is shown that the method used by Genannt and Pilkuhn (1973) to calculate tsub(coh) (which gave values of t0 for N2 and O2) that were 5% less than those assuming Thomas-Fermi molecular nitrogen is about 1% greater than for atomic nitrogen. The best value to use at present for t0(air) is 36.1g/cm2, the Thomas-Fermi value (without any molecular binding correction)

  6. 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)

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

    OpenAIRE

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

    2012-01-01

    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 pro...

  8. 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

  9. Modeling air travel behavior

    OpenAIRE

    Warburg, Valdemar; Nielsen, Otto Anker; Bhat, Chandra

    2006-01-01

    Modeling passengers’ flight choice behavior is valuable to understanding the increasingly competitive airline market and predicting air travel demands. This report estimates standard and mixed multinomial logit models of itinerary choice for business travel, based on a stated preference survey conducted in 2001. Previous work on air travel behavior modeling hasalmost exclusively been confined to studying either airport or airline choice. However, two recent papers have expanded the s...

  10. Cosmic radiation and air crew exposure

    International Nuclear Information System (INIS)

    When the primary particles from space, mainly protons, enter the atmosphere, they interact with the air nuclei and induce cosmic-ray shower. When an aircraft is in the air, the radiation field within includes many types of radiation of large energy range; the field comprises mainly photons, electrons, positrons and neutrons. Cosmic radiation dose for crews of air crafts A 320 and ATR 42 was measured using TLD-100 (LiF: Mg, Ti) detectors and the Mini 6100 semiconductor dosimeter; radon concentration in the atmosphere was measured using the Alpha Guard radon detector. The total annual dose estimated for the A 320 aircraft crew, at altitudes up to 12000 meters, was 5.3 mSv (including natural radon radiation dose of 1.1 mSv).(author)

  11. 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.

  12. 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?3.65?m] the band to the whole [0.2?100?m] 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 12?m 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

  13. Subsonic radiation waves in air

    International Nuclear Information System (INIS)

    It is shown that fast waves of absorption of laser radiation with the propagation mechanism dominated by the role of the intrinsic radiation emitted from the resultant plasma may appear at flux densities at least an order of magnitude lower than those at which they have been observed experimentally. An expanding plasma generates a shock wave where the pressure is much higher than atmospheric. Numerical calculations relating to the spectral radiation-dynamic problem are used to study the evolution of such subsonic radiation waves traveling from the initial plasma layer and to determine the time dependences of their main parameters (up to the quasisteady propagation stage). It is shown that these effects may occur when the flux (power) density exceeds 0.1 MW/cm2 for CO2 lasers and 1 MW/cm2 for neodymium lasers

  14. 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

  15. REGULATORY AIR QUALITY MODELS

    Science.gov (United States)

    Appendix W to 40CFR Part 51 (Guideline on Air Quality Models) specifies the models to be used for purposes of permitting, PSD, and SIPs. Through a formal regulatory process this modeling guidance is periodically updated to reflect current science. In the most recent action, thr...

  16. 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 ssing 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

  17. Radiation control coatings installed on federal buildings at Tyndall Air Force Base. Volume 2: Long-term monitoring and modeling

    Energy Technology Data Exchange (ETDEWEB)

    Petrie, T.W.; Childs, P.W.

    1998-06-01

    The US Department of Energy`s (DOE`s) Federal Energy Management Program (FEMP) supports efforts to reduce energy use and associated expenses in the federal sector. One such effort, the New Technology Demonstration Program (NTDP), seeks to evaluate new energy-saving US technologies and secure their more timely adoption by the US government. Through a partnership with a federal site, the utility serving the site, a manufacturer of an energy-related technology, and other organizations associated with these interests, DOE can evaluate a new technology. The results of the program give federal agency decision makers more hands-on information with which to validate a decision to utilize a new technology in their facilities. This is the second volume of a two-volume report that describes the effects of radiation control coatings installed on federal buildings at Tyndall Air Force Base (AFB) in Florida by ThermShield International. ORNL`s Buildings Technology Center (BTC) was assigned the responsibility for gathering, analyzing, and reporting on the data to describe the effects of the coatings. The first volume described the monitoring plan and its implementation, the results of pre-coating monitoring, the coating installation, results from fresh coatings compared to pre-coating results, and a plan to decommission the monitoring equipment. This second volume updates and completes the presentation of data to compare performance of fresh coatings with weathered coatings.

  18. Sensitivity of contrail cirrus radiative forcing to air traffic scheduling

    Science.gov (United States)

    Newinger, Christina; Burkhardt, Ulrike

    2012-05-01

    Air traffic effects high cloudiness and therefore the Earth's radiation budget by producing contrail cirrus. Contrail cirrus comprise of line-shaped contrails and irregularly shaped ice clouds that originate from them. The warming effect of contrail cirrus is disproportionally large at night, since at daytime the cooling due to the short wave cloud albedo effect acts toward compensating the long wave warming effect. Therefore it has been suggested to restrict air traffic to daytime in order to reduce its climate impact. The potential for reducing the contrail cirrus radiative forcing by shifting air traffic to daytime depends on the diurnal cycle of contrail cirrus coverage which is in turn determined by the diurnal cycle of air traffic and the contrail cirrus lifetimes. Simulations with a global atmospheric general circulation model indicate that the annual mean contrail cirrus coverage may be almost constant over the day even in areas where air traffic is close to zero at night. A conceptual model describing the temporal evolution of contrail cirrus coverage reveals that this is due to the large variability in contrail cirrus lifetimes in combination with the spreading of contrail cirrus. This large variability of lifetimes is consistent with observational evidence but more observations are needed to constrain the contrail lifetime distribution. An idealized mitigation experiment, shifting nighttime flights to daytime, indicates that contrail cirrus radiative forcing is not significantly changed.

  19. Air quality model guideline

    International Nuclear Information System (INIS)

    Alberta Environment has developed a guidelines for operations and proposed operations that require approvals under the province's Environmental Protection and Enhancement Act or that operate under a code of practice for emissions to the atmosphere. In an effort to ensure consistency in the use of dispersion models for regulatory applications in Alberta, this document provided detailed guidance on suitable methods and approaches that should be employed to assess air quality from emission sources, specifically, information required to demonstrate that a source meets the Alberta ambient air quality objectives. The document outlined the statutory authority and provided an overview of the approach. It provided detailed advice on the types and uses of dispersion models with particular reference to the modelling protocol, input data, and output interpretation. Guidance on the application of regulatory models were also presented. Various models were described and their intended uses were explained. Internet addresses for different modelling resources were also offered. Last, some information about regional modelling in the province of Alberta was discussed. 40 refs., 4 tabs., 7 figs., 3 appendices.

  20. 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

  1. 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 ?Sv 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)

  2. Sound radiation into air by a point source moving underwater

    Science.gov (United States)

    Deng, Yiqing; Tao, Jiancheng; Qiu, Xiaojun

    2012-09-01

    Based on the discovery that the majority of radiated energy of a stationary sound source in shallow water is into the air at infrasonic frequencies, the sound transmission into air from a point source moving underwater is investigated in this letter. It is found that a moving sound source can radiate more acoustic energy into the air than a stationary one and the amount of energy radiated into the air increases with the speed of the moving source. Simulations show that the sound transmission into air is dominated by the inhomogeneous waves generated by the moving source.

  3. 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 represdistribution of precipitation represent important sources of uncertainty in the response of air quality to global warming. (letter)

  4. 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)

  5. Infrared band absorptance correlations and applications to nongray radiation. [mathematical models of absorption spectra for nongray atmospheres in order to study air pollution

    Science.gov (United States)

    Tiwari, S. N.; Manian, S. V. S.

    1976-01-01

    Various mathematical models for infrared radiation absorption spectra for atmospheric gases are reviewed, and continuous correlations for the total absorptance of a wide band are presented. Different band absorptance correlations were employed in two physically realistic problems (radiative transfer in gases with internal heat source, and heat transfer in laminar flow of absorbing-emitting gases between parallel plates) to study their influence on final radiative transfer results. This information will be applied to the study of atmospheric pollutants by infrared radiation measurement.

  6. 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

  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. Free Fall Air Resistance Model

    Science.gov (United States)

    2010-04-27

    This simulation allows students to compare the motion of free falling objects with and without the influence of air resistance. Air resistance is the result of collisions of the object's leading surface with air molecules. On Earth, objects falling through the air usually encounter some sort of air resistance, though the amount is dependent upon several factors. In this model, a blue ball falls under the influence of gravity alone. A falling red ball is subject to both gravity and air resistance. Students can adjust the amount of air resistance with a slider. When the simulation is played, graphs are simultaneously plotted that show position vs. time, velocity vs. time, and acceleration vs. time for both falling balls. See Annotations for an editor-recommended, interactive tutorial that further explains free fall and air resistance. This item was created with Easy Java Simulations (EJS), a modeling tool that allows users without formal programming experience to generate computer models and simulations. To run the simulation, simply click the Java Archive file below. To modify or customize the model, See Related Materials for detailed instructions on installing and running the EJS Modeling and Authoring Tool.

  9. 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

  10. 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.

  11. 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

  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. Acute radiation risk models

    Science.gov (United States)

    Smirnova, Olga

    Biologically motivated mathematical models, which describe the dynamics of the major hematopoietic lineages (the thrombocytopoietic, lymphocytopoietic, granulocytopoietic, and erythropoietic systems) in acutely/chronically irradiated humans are developed. These models are implemented as systems of nonlinear differential equations, which variables and constant parameters have clear biological meaning. It is shown that the developed models are capable of reproducing clinical data on the dynamics of these systems in humans exposed to acute radiation in the result of incidents and accidents, as well as in humans exposed to low-level chronic radiation. Moreover, the averaged value of the "lethal" dose rates of chronic irradiation evaluated within models of these four major hematopoietic lineages coincides with the real minimal dose rate of lethal chronic irradiation. The demonstrated ability of the models of the human thrombocytopoietic, lymphocytopoietic, granulocytopoietic, and erythropoietic systems to predict the dynamical response of these systems to acute/chronic irradiation in wide ranges of doses and dose rates implies that these mathematical models form an universal tool for the investigation and prediction of the dynamics of the major human hematopoietic lineages for a vast pattern of irradiation scenarios. In particular, these models could be applied for the radiation risk assessment for health of astronauts exposed to space radiation during long-term space missions, such as voyages to Mars or Lunar colonies, as well as for health of people exposed to acute/chronic irradiation due to environmental radiological events.

  14. The importance of the diurnal and annual cycle of air traffic for contrail radiative forcing.

    Science.gov (United States)

    Stuber, Nicola; Forster, Piers; Rädel, Gaby; Shine, Keith

    2006-06-15

    Air traffic condensation trails, or contrails, are believed to have a net atmospheric warming effect, although one that is currently small compared to that induced by other sources of human emissions. However, the comparably large growth rate of air traffic requires an improved understanding of the resulting impact of aircraft radiative forcing on climate. Contrails have an effect on the Earth's energy balance similar to that of high thin ice clouds. Their trapping of outgoing longwave radiation emitted by the Earth and atmosphere (positive radiative forcing) is partly compensated by their reflection of incoming solar radiation (negative radiative forcing). On average, the longwave effect dominates and the net contrail radiative forcing is believed to be positive. Over daily and annual timescales, varying levels of air traffic, meteorological conditions, and solar insolation influence the net forcing effect of contrails. Here we determine the factors most important for contrail climate forcing using a sophisticated radiative transfer model for a site in southeast England, located in the entrance to the North Atlantic flight corridor. We find that night-time flights during winter (December to February) are responsible for most of the contrail radiative forcing. Night flights account for only 25 per cent of daily air traffic, but contribute 60 to 80 per cent of the contrail forcing. Further, winter flights account for only 22 per cent of annual air traffic, but contribute half of the annual mean forcing. These results suggest that flight rescheduling could help to minimize the climate impact of aviation. PMID:16778887

  15. 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.

  16. Origin of photoionizing radiation in corona discharges in air

    International Nuclear Information System (INIS)

    A hypothesis by Akishev et al (1999 J. Phys. D: Appl. Phys. 32 2399-409), that the photoionizing radiation emitted by the positive corona discharge in air is soft x-rays generated by electron bombardment of the anode surface, is discussed. Absorption curves of the photoionizing radiation generated by positive and negative coronae in atmospheric air are compared. The coincidence of the shapes of these curves confirms the earlier, widely accepted opinion that the photoionizing radiation is emitted by gas molecules and atoms, which are excited via electron collision. Photographic detection of this photoionizing radiation performed by the method proposed by Akishev et al is found to be improbable, because of the very high attenuation of radiation by the light protecting envelope around the photographic film. (author)

  17. Frontiers in air quality modelling

    OpenAIRE

    Colette, A.; Bessagnet, B.; Meleux, F.; Rouïl, L.

    2013-01-01

    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 fi...

  18. Coherent Cherenkov Radiation from Cosmic-Ray-Induced Air Showers

    International Nuclear Information System (INIS)

    Very energetic cosmic rays entering the atmosphere of Earth will create a plasma cloud moving with almost the speed of light. The magnetic field of Earth induces an electric current in this cloud which is responsible for the emission of coherent electromagnetic radiation. We propose to search for a new effect: Because of the index of refraction of air, this radiation is collimated in a Cherenkov cone. To express the difference from usual Cherenkov radiation, i.e., the emission from a fast-moving electric charge, we call this magnetically induced Cherenkov radiation. We indicate its signature and possible experimental verification.

  19. 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.

  20. Frontiers in air quality modelling

    Science.gov (United States)

    Colette, A.; Bessagnet, B.; Meleux, F.; Terrenoire, E.; Rouïl, L.

    2014-01-01

    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 of the contribution of individual city plumes to the European burden of pollution, providing new insights to target the appropriate geographical level of action when designing air pollution mitigation strategies.

  1. 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.

  2. 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

  3. 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.

  4. 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 plasmaurface 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)

  5. 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.)

  6. Water, Air, Earth and Cosmic Radiation

    Science.gov (United States)

    Bassez, Marie-Paule

    2015-03-01

    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.

  7. 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.

  8. 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. PMID:25777464

  9. Mesoscale air pollution dispersion modelling

    Science.gov (United States)

    Van Dop, H.; De Haan, B. J.

    An air pollution model is developed which describes the transport of pollutants on a scale of 500 × 500 km2. This corresponds with episodes of a few days. In the model a detailed description is given of the vertical diffusion processes under different stability conditions. Also much effort is put into the determination of the horizontal mean wind field, which is strongly non-homogeneous and non-stationary on the above space- and timescales. The transport equation is numerically solved. For the advective part a pseudo-spectral scheme was applied. The vertical diffusion is treated with a Crank-Nicolson scheme. Dry deposition is included in the model in a way which accounts for the chemical properties of pollutant and soil. Wet deposition and chemical transport are included by simple linear decay terms. The model is tested in a complex source area (Netherlands and surrounding countries), during a fair weather episode on 29 and 30 May 1978. The model gives a satisfactory description of the fumigation process. Also other diurnal variations in atmospheric stability are well reflected in the concentration distribution The effect of dry deposition is studied. The moderate computer time requirements make the model particularly apt for practical applications.

  10. Air crew exposure to cosmic radiation. New analysis, recommendations EURADOS

    International Nuclear Information System (INIS)

    Cosmic radiation on the board of an aircraft consist of two components: directly ionizing radiation (electron, proton - low LET) and neutrons (high LET). Neither composition nor the energy spectrum of usual on-Earth calibration sources (60Co, 252Cf) do not correspond to the field on a board. Therefore high energy reference fields behind shielding high energy accelerator at CERN and Dubna have been created and intensively studied. Their typical characteristics following from the results of our measurements were obtained. In-flight measurements on the board of commercial aircraft have been realized since 1991 during about 20 flights, Flight routes extended from the 1.3 grad N up to about 65 grad N, flying altitudes varied from 8.2 km to 12.5 km. The exposure level due to galactic cosmic radiation is inversely proportional to the solar activity. Some radiation protection aspects were concluded: (a) The usual limits of annual air crew flight hours correspond at 11.3 km to about 4 mSv per year, with new ICRP conversion factors to about 5 mSv per year; (b) Monthly flight hours limit does not exclude that the exposure of a pregnant women can exceed 1 mSv during this period; (c) The air crew exposure should therefore be checked, controlled a nd administered as conscientiously as for any other group of occupationally exposed persons. A Working group 11 of EURADOS 'Exposure of air crew to cosmic radiation' has been formed (1992-1995) to prepare basic analysis and recommendations concerning the topics. The basic recommendations are the following: (a) air crew flying routinely at altitudes over 8 km are deemed to be category B workers, it is therefore important to estimate, record, control and, where necessary, to limit the doses; (b) the preferred procedure in order to estimate doses to air crew or frequent flyers is to determine route doses and fold these data with data on staff rostering; (c) where doses may exceed the limit for category B workers (6 mSv per year), on-board monitoring of dose may be appropriate; (d) an equivalent-dose limit of 1 mSv for the embryo and foetus should be specify for air crew (J.K.). 2 tabs., 12 refs

  11. 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 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 and using simple Monte Carlo techniques to obtain a stochastic estimate of the costs of traffic air pollution for infrastructures.

  12. 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

  13. 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

  14. Emission scenario model for regional air pollution

    OpenAIRE

    Karvosenoja, Niko

    2008-01-01

    Air pollution emissions are produced in a wide variety of sources. They often result in detrimental impacts on both environments and human populations. To assess the emissions and impacts of air pollution, mathematical models have been developed. This study presents results from the application of an air pollution emission model, the Finnish Regional Emission Scenario (FRES) model, that covers the emissions of sulfur dioxide (SO2), nitrogen oxides (NOx), ammonia (NH3), non-methane volatile or...

  15. 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 caly 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 ?Sv 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)

  16. Solar radiation models - review

    OpenAIRE

    M. Jamil Ahmad, G.N. Tiwari, Anil Kumar Singh, Manisha Sharma, H.N. Singh

    2010-01-01

    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 ...

  17. 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.

  18. Preclinical models in radiation oncology

    OpenAIRE

    Kahn Jenna; Tofilon Philip J; Camphausen Kevin

    2012-01-01

    Abstract 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 em...

  19. 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.

  20. Air pollution model for point source

    OpenAIRE

    Jozef Ma?ala; 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...

  1. Two Dimensional Air Drop Model

    Science.gov (United States)

    Francisco Esquembre

    2014-06-12

    This interactive simulation shows an airplane flying at constant horizontal velocity preparing to drop relief supplies to a small island. Download Simulation Below As captain of the plane, you must determine when to release the package and activate the release button. The trajectory of the falling package is traced onscreen. If you were too far off, the package will drop in the ocean. The motion can be viewed from the perspective of a person standing on the island or an airplane flying nearby. Extend the learning by activating air friction to see how this variable affects the motion of the projectile. Editor's Note: Students may insist that there is a horizontal force acting upon the package since it has a horizontal motion. See Annotation for an editor-recommended tutorial that will explain what is happening (the horizontal motion of the package results from its inertia). This item was created with Easy Java Simulations (EJS), a modeling tool that allows users without formal programming experience to generate computer models and simulations.

  2. Biophysical modelling of radiation effects

    International Nuclear Information System (INIS)

    Radiation Protection Programme of DGXII of the Commission of the European Communities, the Office for Health and Environmental Research of the United States Department of Energy and the Istituto Nazionale di Fisica Nucleare at Legnaro in Italy organized a workshop on Biophysical Modelling of Radiation Effects in Padua from 2--5 September 1991 to bring together the proponents of the different biophysical models in an objective review of the current status. This book presents the proceedings and the essential discussion from that workshop. Three sets of radiobiological data on cell transformation, chromosomal aberrations and mutations and on the interaction of mixed radiations were offered for analysis by the modellers and some of the presentations in this book deal with those analyses. Other presentations cover the recent development of the existing models as well as defining newer data sets which might be used to test the different models. The book should be of interest to radiation biophysicists, theoretical radiation biologists, microdosimetrists, and all those scientists who are involved with the application of models in radiation therapy and in the assessment of risk from low doses of ionizing radiation

  3. 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

  4. Radiation safety of crew and passengers of air transportation in civil aviation. Provisional standards

    Science.gov (United States)

    Aksenov, A. F.; Burnazyan, A. I.

    1985-01-01

    The purpose and application of the provisional standards for radiation safety of crew and passengers in civil aviation are given. The radiation effect of cosmic radiation in flight on civil aviation air transport is described. Standard levels of radiation and conditions of radiation safety are discussed.

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

    OpenAIRE

    Kloster, S.; Dentener, F; Feichter, J; Raes, F.; van Aardenne, J.; Roeckner, E.; Lohmann, U.; Stier, P.; Swart, R.

    2008-01-01

    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 re...

  6. 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. ching 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 1½ 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)

  7. OpenAIRE - Data Model Specification

    OpenAIRE

    2010-01-01

    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...

  8. 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. Howe...

  9. Mathematical modeling of photochemical air pollution

    International Nuclear Information System (INIS)

    This paper summarizes the key elements of a project directed at developing a comprehensive mathematical model capable of describing the formation and transport of chemically reacting species in the turbulent planetary boundary layer. The model is intended for routine application in the design and evaluation of urban-scale air pollution control strategies. Some examples illustrating the use of the model in the South Coast Air Basin of Southern California are presented

  10. 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)

  11. Mixed conflict model for Air Traffic Control

    OpenAIRE

    Feydy, Thibaut; Barnier, Nicolas; Brisset, Pascal; Durand, Nicolas

    2005-01-01

    Airspace congestion is today the most critical issue European Air Traffic Management (ATM) has to face. Current real-time Air Traffic Control (ATC) is achieved by human controllers. One of their main tasks is to keep separation between aircraft, asking to the pilots to do basic avoidance manoeuvres. We propose here two mixed CSP models of this separation issue, combining discrete and continuous variables. An implementation of these models allows to produce optimal solutions for problems where...

  12. Model For Indoor Dispersion Of Air Pollutants

    Science.gov (United States)

    ?tefan, Sabina; Filip, Lumini?a; Rusu-Zagar, Gilda; Stepa, Raluca

    2007-04-01

    A model for computing the time evolution of concentrations of various air pollutants in closed working areas was constructed. The model uses a partition of the working unit in a convenient number of cells with known transfer and ventilation air fluxes. Then, a time-dependent injection of pollutants occurring in various sites of the working space determine the subsequent evolution of pollutant concentrations in all the compartments of the partition.

  13. 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

  14. REAS3: Modeling Radio Emission from Cosmic Ray Air Showers

    Science.gov (United States)

    Ludwig, Marianne; Huege, Tim

    2011-07-01

    In recent years, the freely available Monte Carlo code REAS for modelling radio emission from cosmic ray air showers has evolved to include the full complexity of air shower physics. However, it turned out that in REAS2 and all other time-domain models which calculate the radio emission by superposing the radiation of the single air shower electrons and positrons, the calculation of the emission contributions was not fully consistent. In this article, we present a revised implementation in REAS3, which incorporates the missing radio emission due to the variation of the number of charged particles during the air shower evolution using an "end-point formalism". With the inclusion of these emission contributions, the structure of the simulated radio pulses changes from unipolar to bipolar, and the azimuthal emission pattern becomes nearly symmetric. Remaining asymmetries can be explained by radio emission due to the variation of the net charge excess in air showers, which is automatically taken into account in the new implementation. REAS3 constitutes the first self-consistent time-domain implementation based on single particle emission taking the full complexity of air shower physics into account, and is freely available for all interested users.

  15. Air Quality – monitoring and modelling

    OpenAIRE

    Marius DEACONU; Mihaiella CRETU

    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...

  16. 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.

  17. Modelling of radiation transport

    International Nuclear Information System (INIS)

    In the application of nuclear radiation, the problem of the transport of photons and neutral or charged particles through the matter is central for understanding the physics of the process, for a correct interpretation of the measurement and for a convenient choice of instrumental operating conditions. This paper, in the first part, is intended as a survey of the genesis of the transport equations, which describe the phenomenon of the diffusion of the particles. With a regressive procedure, it is possible to obtain the commonly used transport equations directly from Liouville equation; the approximations that must always been involved can be related to two dimensionless parameters if suitable dimesionless variables are introduced. In the second part, approximate solutions of Boltzmann and Fokker-Planck equations are given for particular physical situations of interest in X-ray spectroscopy and electron microprobe analysis

  18. Mathematical Models for Room Air Distribution

    OpenAIRE

    Nielsen, Peter V.

    1982-01-01

    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 removed from the room at constant penetration length is proportional to the cube of the velocities in the occupied zone. It is also shown that a large number of diffusers increases the amount of heat...

  19. Radiative Neutrino Mass Models

    CERN Document Server

    Sugiyama, Hiroaki

    2015-01-01

    In this short review, we see some typical models in which light neutrino masses are generated at the loop level. These models involve new Higgs bosons whose Yukawa interactions with leptons are constrained by the neutrino oscillation data. Predictions about flavor structures of $\\ell \\to \\overline{\\ell}_1 \\ell_2 \\ell_3$ and leptonic decays of new Higgs bosons via the constrained Yukawa interactions are briefly summarized in order to utilize such Higgs as a probe of $\

  20. Comparison of box-air-mass-factors and radiances for Multiple-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS geometries calculated from different UV/visible radiative transfer models

    Directory of Open Access Journals (Sweden)

    T. Wagner

    2007-01-01

    Full Text Available The results of a comparison exercise of radiative transfer models (RTM of various international research groups for Multiple AXis Differential Optical Absorption Spectroscopy (MAX-DOAS viewing geometry are presented. Besides the assessment of the agreement between the different models, a second focus of the comparison was the systematic investigation of the sensitivity of the MAX-DOAS technique under various viewing geometries and aerosol conditions. In contrast to previous comparison exercises, box-air-mass-factors (box-AMFs for different atmospheric height layers were modelled, which describe the sensitivity of the measurements as a function of altitude. In addition, radiances were calculated allowing the identification of potential errors, which might be overlooked if only AMFs are compared. Accurate modelling of radiances is also a prerequisite for the correct interpretation of satellite observations, for which the received radiance can strongly vary across the large ground pixels, and might be also important for the retrieval of aerosol properties as a future application of MAX-DOAS. The comparison exercises included different wavelengths and atmospheric scenarios (with and without aerosols. The strong and systematic influence of aerosol scattering indicates that from MAX-DOAS observations also information on atmospheric aerosols can be retrieved. During the various iterations of the exercises, the results from all models showed a substantial convergence, and the final data sets agreed for most cases within about 5%. Larger deviations were found for cases with low atmospheric optical depth, for which the photon path lengths along the line of sight of the instrument can become very large. The differences occurred between models including full spherical geometry and those using only plane parallel approximation indicating that the correct treatment of the Earth's sphericity becomes indispensable. The modelled box-AMFs constitute an universal data base for the calculation of arbitrary (total AMFs by simple convolution with a given trace gas concentration profile. Together with the modelled radiances and the specified settings for the various exercises, they can serve as test cases for future RTM developments.

  1. Neural models project for solar radiation and atmospheric temperature forecast

    OpenAIRE

    Martins, I.

    2009-01-01

    This work arises from the necessity of temperature and solar radiation forecast, to improve the Heating, Ventilating, and Air Conditioning (HVAC) systems e ciency. To do so, it was necessary to determine neural models capable of such forecast. The chosen characteristics were solar radiation and temperature because these two characteristics directly a ect the room temperature inside a building. This forecast system will be implemented on a portable computational device, so it mu...

  2. 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...

  3. A Neural Network Based Intelligent Predictive Sensor for Cloudiness, Solar Radiation and Air Temperature

    Directory of Open Access Journals (Sweden)

    Pedro M. Ferreira

    2012-11-01

    Full Text Available Accurate measurements of global solar radiation and atmospheric temperature,as well as the availability of the predictions of their evolution over time, are importantfor different areas of applications, such as agriculture, renewable energy and energymanagement, or thermal comfort in buildings. For this reason, an intelligent, light-weightand portable sensor was developed, using artificial neural network models as the time-seriespredictor mechanisms. These have been identified with the aid of a procedure based on themulti-objective genetic algorithm. As cloudiness is the most significant factor affecting thesolar radiation reaching a particular location on the Earth surface, it has great impact on theperformance of predictive solar radiation models for that location. This work also representsone step towards the improvement of such models by using ground-to-sky hemisphericalcolour digital images as a means to estimate cloudiness by the fraction of visible skycorresponding to clouds and to clear sky. The implementation of predictive models inthe prototype has been validated and the system is able to function reliably, providingmeasurements and four-hour forecasts of cloudiness, solar radiation and air temperature.

  4. Adaptive Grid Use in Air Quality Modeling

    Directory of Open Access Journals (Sweden)

    Mehmet Talat Odman

    2011-09-01

    Full Text Available The predictions from air quality models are subject to many sources of uncertainty; among them, grid resolution has been viewed as one that is limited by the availability of computational resources. A large grid size can lead to unacceptable errors for many pollutants formed via nonlinear chemical reactions. Further, insufficient grid resolution limits the ability to perform accurate exposure assessments. To address this issue in parallel to increasing computational power, modeling techniques that apply finer grids to areas of interest and coarser grids elsewhere have been developed. Techniques using multiple grid sizes are called nested grid or multiscale modeling techniques. These approaches are limited by uncertainty in the placement of finer grids since pertinent locations may not be known a priori, loss in solution accuracy due to grid boundary interface problems, and inability to adjust to changes in grid resolution requirements. A different approach to achieve local resolution involves using dynamic adaptive grids. Various adaptive mesh refinement techniques using structured grids as well as mesh enrichment techniques on unstructured grids have been explored in atmospheric modeling. Recently, some of these techniques have been applied to full blown air quality models. In this paper, adaptive grid methods used in air quality modeling are reviewed and categorized. The advantages and disadvantages of each adaptive grid method are discussed. Recent advances made in air quality simulation owing to the use of adaptive grids are summarized. Relevant connections to adaptive grid modeling in weather and climate modeling are also described.

  5. Radiation transfer in air and air-Cu plasmas for two temperature profiles

    Science.gov (United States)

    Kloc, P.; Aubrecht, V.; Bartlova, M.; Coufal, O.

    2015-02-01

    In this article we present our results from calculations of the divergence of the radiation flux in a high temperature air-Cu plasma arc. We assumed stationary plasma, with local thermodynamic equilibrium valid throughout the plasma volume. We paid attention especially to the presence of copper lines in the absorption coefficient spectra and their influence on the energy transfer. Two distinct temperature regimes were used, with one focusing on a steep temperature gradient and the other involving a slowly varying temperature profile. The temperature ranges from 25 kK at the arc center down to 3 kK at the plasma arc boundary. Uniform pressure of 1 bar was considered in all cases. The results show that a large amount of energy is emitted by the copper vapor, which helps with cooling the arc.

  6. Radiative properties and radiative transfer in high pressure thermal air plasmas

    International Nuclear Information System (INIS)

    The aim of this paper is to investigate radiative properties of thermal air plasmas in wide ranges of pressure and temperature, and to analyse the accuracy of some spectral and geometrical approximations in high-pressure radiative transfer applications. Comprehensive calculations of absorption spectra, including molecular, atomic and ionic line and continuum radiation, are presented and the dependence of these spectra on the pressure level is analysed. The high resolution spectra, in association with a rigorous ray-tracing method, are then used to study the accuracy of the P1 and the simplified SP3 geometrical approximations in 1D axisymmetric geometries. Cylindrical plasma columns at uniform pressure and with a non-uniform pressure distribution are considered. The P1 approximation provides acceptable results but the SP3 approximation is found to be more accurate. Concerning the spectral approximations, the use of band averaged Rosseland mean absorption coefficients yields volumetric radiative powers in fairly good agreement with line-by-line calculations.

  7. 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.

  8. 10 CFR Appendix A to Part 835 - Derived Air Concentrations (DAC) for Controlling Radiation Exposure to Workers at DOE Facilities

    Science.gov (United States)

    2010-01-01

    ...Derived Air Concentrations (DAC) for Controlling Radiation Exposure to Workers at DOE...Derived Air Concentrations (DAC) for Controlling Radiation Exposure to Workers at DOE...presented in appendix A are to be used for controlling individual internal doses in...

  9. Air pollution modelling in Cape Town

    Energy Technology Data Exchange (ETDEWEB)

    Dracoulides, D.A.; Dutkiewicz, R.K. [Cape Town Univ. (South Africa)

    1995-12-31

    The degradation of air quality in the modern metropolitan areas has dictated the need to regulate the environmental effects of energy usage. In South Africa, the Atmospheric Pollution Prevention Act No. 45 of 1965 assisted in setting the basis for air-pollution control policies. An air pollution control programme, initiated in Cape Town in 1968, resulted in great improvement in the measured concentrations. Dispersion models provide the capability of assessing the effect of pollution control policies on ambient air quality. This presentation describes work carried out on a comparison of measured pollution levels in Greater Cape Town (GCT) with that predicted using an EPA environmental model. The chosen model for this study was the Industrial Source Complex Short Term 2 (ISCST2). Due allowance has to be made for the topographical complexity of the region, and the model is accepted as being applicable to certain areas under given meteorological conditions. The model`s accuracy is assessed with the use of available hourly SO{sub 2} concentrations, at three monitoring stations in the area and under different meteorological conditions

  10. Radiation dosimetry and biophysical models of space radiation effects

    Science.gov (United States)

    Cucinotta, Francis A.; Wu, Honglu; Shavers, Mark R.; George, Kerry

    2003-01-01

    Estimating the biological risks from space radiation remains a difficult problem because of the many radiation types including protons, heavy ions, and secondary neutrons, and the absence of epidemiology data for these radiation types. Developing useful biophysical parameters or models that relate energy deposition by space particles to the probabilities of biological outcomes is a complex problem. Physical measurements of space radiation include the absorbed dose, dose equivalent, and linear energy transfer (LET) spectra. In contrast to conventional dosimetric methods, models of radiation track structure provide descriptions of energy deposition events in biomolecules, cells, or tissues, which can be used to develop biophysical models of radiation risks. In this paper, we address the biophysical description of heavy particle tracks in the context of the interpretation of both space radiation dosimetry and radiobiology data, which may provide insights into new approaches to these problems.

  11. Air Quality Response Modeling for Decision Support

    OpenAIRE

    Sergey L. Napelenok; Cohan, Daniel S.

    2011-01-01

    Air quality management relies on photochemical models to predict the responses of pollutant concentrations to changes in emissions. Such modeling is especially important for secondary pollutants such as ozone and fine particulate matter which vary nonlinearly with changes in emissions. Numerous techniques for probing pollutant-emission relationships within photochemical models have been developed and deployed for a variety of decision support applications. However, atmospheric response modeli...

  12. The air emissions risk assessment model (AERAM)

    International Nuclear Information System (INIS)

    AERAM is an environmental analysis and power generation station investment decision support tool. AERAM calculates the public health risk (in terms of the lifetime cancers) in the nearby population from pollutants released into the air. AERAM consists of four main subroutines: Emissions, Air, Exposure and Risk. The Emission subroutine uses power plant parameters to calculate the expected release of the pollutants. A coal-fired and oil-fired power plant are currently available. A gas-fired plant model is under preparation. The release of the pollutants into the air is followed by their dispersal in the environment. The dispersion in the Air Subroutine uses the Environmental Protection Agency's model, Industrial Source Complex-Long Term. Additional dispersion models (Industrial Source Complex - Short Term and Cooling Tower Drift) are being implemented for future AERAM versions. The Expose Subroutine uses the ambient concentrations to compute population exposures for the pollutants of concern. The exposures are used with corresponding dose-response model in the Risk Subroutine to estimate both the total population risk and individual risk. The risk for the dispersion receptor-population centroid for the maximum concentration is also calculated for regulatory-population purposes. In addition, automated interfaces with AirTox (an air risk decision model) have been implemented to extend AERAM's steady-state single solution to the decision-under-uncertainty domain. AERAM wascision-under-uncertainty domain. AERAM was used for public health risks, the investment decision for additional pollution control systems based on health risk reductions, and the economics of fuel vs. health risk tradeoffs. AERAM provides that state-of-the-art capability for evaluating the public health impact airborne toxic substances in response to regulations and public concern

  13. Uncertainty in Regional Air Quality Modeling

    Science.gov (United States)

    Digar, Antara

    Effective pollution mitigation is the key to successful air quality management. Although states invest millions of dollars to predict future air quality, the regulatory modeling and analysis process to inform pollution control strategy remains uncertain. Traditionally deterministic ‘bright-line’ tests are applied to evaluate the sufficiency of a control strategy to attain an air quality standard. A critical part of regulatory attainment demonstration is the prediction of future pollutant levels using photochemical air quality models. However, because models are uncertain, they yield a false sense of precision that pollutant response to emission controls is perfectly known and may eventually mislead the selection of control policies. These uncertainties in turn affect the health impact assessment of air pollution control strategies. This thesis explores beyond the conventional practice of deterministic attainment demonstration and presents novel approaches to yield probabilistic representations of pollutant response to emission controls by accounting for uncertainties in regional air quality planning. Computationally-efficient methods are developed and validated to characterize uncertainty in the prediction of secondary pollutant (ozone and particulate matter) sensitivities to precursor emissions in the presence of uncertainties in model assumptions and input parameters. We also introduce impact factors that enable identification of model inputs and scenarios that strongly influence pollutant concentrations and sensitivity to precursor emissions. We demonstrate how these probabilistic approaches could be applied to determine the likelihood that any control measure will yield regulatory attainment, or could be extended to evaluate probabilistic health benefits of emission controls, considering uncertainties in both air quality models and epidemiological concentration-response relationships. Finally, ground-level observations for pollutant (ozone) and precursor concentrations (oxides of nitrogen) have been used to adjust probabilistic estimates of pollutant sensitivities based on the performance of simulations in reliably reproducing ambient measurements. Various observational metrics have been explored for better scientific understanding of how sensitivity estimates vary with measurement constraints. Future work could extend these methods to incorporate additional modeling uncertainties and alternate observational metrics, and explore the responsiveness of future air quality to project trends in emissions and climate change.

  14. 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

  15. Overview of Atmospheric Ionizing Radiation (AIR) Research: SST - Present

    Science.gov (United States)

    Wilson, J. W.; Goldhagen, P.; Rafnsson, V.; Clem, J. M.; DeAngelis, G.; Friedberg, W.

    2002-01-01

    The Supersonic Transport (SST) program, proposed in 1961, first raised concern for the exposure of pregnant occupants by solar energetic particles (SEP), and neutrons were suspected to have a main role in particle propagation deep into the atmosphere. An eight-year flight program confirmed the role of SEP as a significant hazard and of the neutrons as contributing over half of the galactic cosmic ray (GCR) exposures, with the largest contribution from neutrons above 10 MeV. The FAA Advisory Committee on the Radiobiological Aspects of the SST provided operational requirements. The more recent (1990) lowering of recommended exposure limits by the International Commission on Radiological Protection with the classification of aircrew as "radiation workers" renewed interest in GCR background exposures at commercial flight altitudes and stimulated epidemiological studies in Europe, Japan, Canada and the USA. The proposed development of a High Speed Civil Transport (HSCT) required validation of the role of high-energy neutrons, and this resulted in ER-2 flights at solar minimum (June 1997) and studies on effects of aircraft materials on interior exposures. Recent evaluation of health outcomes of DOE nuclear workers resulted in legislation for health compensation in year 2000 and recent European aircrew epidemiological studies of health outcomes bring renewed interest in aircraft radiation exposures. As improved radiation models become available, it is imperative that a corresponding epidemiological program of US aircrew be implemented.

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

    Science.gov (United States)

    Kloster, S.; Dentener, F.; Feichter, J.; Raes, F.; van Aardenne, J.; Roeckner, E.; Lohmann, U.; Stier, P.; Swart, R.

    2008-11-01

    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.

  17. 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.

  18. Air quality modeling in Warsaw Metropolitan Area

    Directory of Open Access Journals (Sweden)

    Piotr Holnicki

    2013-04-01

    Full Text Available 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. However, due to the complexity of the forecasting system and the required input data, such environmental prognosis and related decisions contain many potential sources of imprecision and uncertainty. The main sources of uncertainty are commonly considered meteorological and emission input data. This paper addresses the problem of emission uncertainty, and impact of this uncertainty on the forecasted air pollution concentrations and adverse health effects. The computational experiment implemented for Warsaw Metropolitan Area, Poland, encompasses one-year forecast with the year 2005 meteorological dataset. The annual mean concentrations of the main urban pollutants are computed. The impact of uncertainty in emission field inventory is also considered. Uncertainty assessment is based on the Monte Carlo technique where the regional scale CALPUFF model is the main forecasting tool used in air quality analysis.

  19. 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.

  20. 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.

  1. DESCRIPTION OF ATMOSPHERIC TRANSPORT PROCESSES IN EULERIAN AIR QUALITY MODELS

    Science.gov (United States)

    Key differences among many types of air quality models are the way atmospheric advection and turbulent diffusion processes are treated. Gaussian models use analytical solutions of the advection-diffusion equations. Lagrangian models use a hypothetical air parcel concept effecti...

  2. Adaptive Grid Use in Air Quality Modeling

    OpenAIRE

    Mehmet Talat Odman; Fernando Garcia-Menendez

    2011-01-01

    The predictions from air quality models are subject to many sources of uncertainty; among them, grid resolution has been viewed as one that is limited by the availability of computational resources. A large grid size can lead to unacceptable errors for many pollutants formed via nonlinear chemical reactions. Further, insufficient grid resolution limits the ability to perform accurate exposure assessments. To address this issue in parallel to increasing computational power, modeling techniques...

  3. Dispersion model maps spread of Fukushima radiation

    Science.gov (United States)

    Schultz, Colin

    2013-01-01

    When water flooded the Japanese Fukushima Daiichi nuclear power plant on 11 March 2011, killing power to the plant and destroying its backup generators, the earthquake-triggered disaster resulted in a major nuclear accident, with the plant pouring radioactive material into the air and the water. Research into the effects of the radiation on humans and the environment has been ongoing, but to ensure the accuracy of these aftermath investigations requires understanding the precise concentrations, distribution patterns, and timing of the radionuclide emissions. To provide such an assessment for the marine environment, Estournel et al. used an ocean and atmosphere dispersion model to simulate the movements of radioactive cesium-137 throughout the Japanese coastal waters for 3.5 months following the earthquake.

  4. 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.

  5. 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.

  6. 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

  7. Solar Radiation Budget from the MRI Radiometers for Clear and Cloudy Air Columns within ARESE II.

    Science.gov (United States)

    Asano, Shoji; Uchiyama, Akihiro; Yamazaki, Akihiro; Kuchiki, Katsuyuki

    2004-12-01

    As an international collaborative research activity within the Japanese Cloud-Climate Study (JACCS) program, the authors participated in the second Atmospheric Radiation Measurement (ARM) Enhanced Shortwave Experiment (ARESE II) using the Meteorological Research Institute (MRI) radiometers. This paper describes results of ARESE II, as well as specifications and calibration of the MRI radiometers. The solar radiation budget for 2 days of typical clear sky (27 February and 20 March 2000) and overcast sky (3 and 21 March 2000) has been analyzed using spatially collocated, total-band solar irradiances measured by the MRI pyranometers (Kipp & Zonen CM21). These were installed on a Twin Otter aircraft, and deployed at the ARM Southern Great Planes Central Facility site. On average, the clear-sky and overcast-sky air columns between the surface and the Twin Otter flight level of 7 km absorbed about 13% ± 2% and 20% ± 3%, respectively, of the total-band solar radiation incident on the column top. The measured solar radiation budgets agree well with those computed for models of clear and cloudy atmospheres. The present results indicate no evidence of anomalous solar absorption for either the clear- or cloudy-sky cases. It is suggested that about half of the observed absorption enhancement of 7% for the overcast-sky cases could be caused by the presence of larger water vapor, compared with the clear-sky cases, and that the other half could be caused by increased absorption within and above the rather low cloud layers.

  8. 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.

  9. 40 CFR 1.41 - Office of Air and Radiation.

    Science.gov (United States)

    2010-07-01

    ...and for providing effective technology transfer through the translation of technological developments into improved control program...standards, and policies; measurement and control of radiation exposure; and research requirements for radiation programs. The...

  10. 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...

  11. 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.

  12. Monterrey, Mexico ozone study: Air quality measurements and photochemical modeling

    Science.gov (United States)

    Martinez Martinez, Jeronimo

    The Monterrey Metropolitan Area is one of the fastest growing areas of Mexico. As a result of this growth, this major urban and industrial center has begun to experience air quality degradation. The Mexican ozone standard (110 ppbv) has been exceeded on 63 days during the period 1993-1995. This study is the first integrated examination of air quality, pollutant emissions, and climate to cover the ozone behavior in Monterrey. Pollutant concentrations and weather conditions were characterized spatially and temporally for all seasons during 1995. Higher ozone concentrations were found in the southwestern region during Spring. Diurnal patterns of ambient concentration ratios and distributions of daily ozone maximum for weekdays and weekends indicate that industrial emissions seem to be a important contributor of ozone formation. Pollutant emissions were estimated from continuous data of air quality network and on-road vehicle emissions. Diurnal patterns of CO and NOx emissions were calculated for January and July 1995 using a flow model based on mass conservation and estimated parameters of lateral advection and chemical loss. To predict how ozone will change in response to prescribed changes in emissions, this emission inventory is consistent and the most reliable. Circulation patterns associated to high-ozone episodes were identified from synoptic meteorological maps. High- pressure systems, migratory anticyclones, elevated mixed layer, cold front passages and mountain-valley winds produced subsidence, flow reversal, and stagnation when elevated ozone affected Monterrey. Hydrocarbon reduction was determined as the most effective strategy for reducing ozone applying a photochemical box model to high-ozone episodes in 1995. Using sensitivity analysis, emissions and meteorological variables were ranked by their relative contributions to ozone formation. The model employs the Carbon Bond Mechanism IV and a hybrid method for solving stiff chemical kinetic equations. The application of this model highlights the major mesoscale and synoptic features of the Monterrey climate. Incursions of air masses of subtropical and midlatitude circulation regimes are highly variable, while high solar radiation occurs all year.

  13. 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.

  14. 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.

  15. 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.

  16. A simple model for cloud radiative forcing

    Directory of Open Access Journals (Sweden)

    T. Corti

    2009-03-01

    Full Text Available We present a simple model for the longwave and shortwave cloud radiative forcing based on the evaluation of extensive radiative transfer calculations. 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 the example of tropical cirrus clouds. We conclude that possible applications for the model include the fast estimate of cloud radiative forcing, the evaluation of the sensitivity to changes in environmental conditions, and as a tool in education.

  17. Updraft Model for Development of Autonomous Soaring Uninhabited Air Vehicles

    Science.gov (United States)

    Allen, Michael J.

    2006-01-01

    Large birds and glider pilots commonly use updrafts caused by convection in the lower atmosphere to extend flight duration, increase cross-country speed, improve range, or simply to conserve energy. Uninhabited air vehicles may also have the ability to exploit updrafts to improve performance. An updraft model was developed at NASA Dryden Flight Research Center (Edwards, California) to investigate the use of convective lift for uninhabited air vehicles in desert regions. Balloon and surface measurements obtained at the National Oceanic and Atmospheric Administration Surface Radiation station (Desert Rock, Nevada) enabled the model development. The data were used to create a statistical representation of the convective velocity scale, w*, and the convective mixing-layer thickness, zi. These parameters were then used to determine updraft size, vertical velocity profile, spacing, and maximum height. This paper gives a complete description of the updraft model and its derivation. Computer code for running the model is also given in conjunction with a check case for model verification.

  18. 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.

  19. 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

  20. Validation of five global radiation models with measured daily data in China

    International Nuclear Information System (INIS)

    Two sunshine based and three air temperature based global radiation models are calibrated using daily data in Jan. 1 1994-Dec. 31 1998 at 48 stations all over China. The Nash-Sutcliffe equation (NSE) is used as the model evaluation criterion. The sunshine based models are suitable for daily global radiation estimation. The averaged NSE value of the Angstroem model is 0.83, and the maximum value is 0.91. The maximum NSE value of the Bahel model is 0.92 with an averaged value of 0.84. The models that use air temperature as the input variable are not suitable for daily global radiation estimation in China. The averaged NSE values of the three air temperature based models (Bristow-Campbell model, Allen model and Hargreaves model) are not larger than 0.47. A logarithmic relationship between the daily global radiation/daily extra-terrestrial solar radiation (RG/RA) and the temperature difference between the maximum and minimum daily air temperature (TM-Tm) is found in the present study. A new daily global radiation model that is a function of RA, sunshine hours and TM-Tm is designed, which gives an averaged NSE value of 0.85 and a maximum value of 0.92

  1. 77 FR 4808 - Conference on Air Quality Modeling

    Science.gov (United States)

    2012-01-31

    ...quality models in Appendix W including the CALPUFF modeling system, AERMOD modeling system...near-field regulatory applications, and the CALPUFF modeling system, the EPA's preferred...preferred air quality models (AERMOD and CALPUFF) status and updates; D. Review of...

  2. 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

  3. 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...

  4. Mathematical Modeling of Photochemical Air Pollution.

    Science.gov (United States)

    McRae, Gregory John

    Air pollution is an environmental problem that is both pervasive and difficult to control. An important element of any rational control approach is a reliable means for evaluating the air quality impact of alternative abatement measures. This work presents such a capability, in the form of a mathematical description of the production and transport of photochemical oxidants within an urban airshed. The combined influences of advection, turbulent diffusion, chemical reaction, emissions and surface removal processes are all incorporated into a series of models that are based on the species continuity equations. A delineation of the essential assumptions underlying the formulation of a three-dimensional, a Lagrangian trajectory, a vertically integrated and single cell air quality model is presented. Since each model employs common components and input data the simpler forms can be used for rapid screening calculations and the more complex ones for detailed evaluations. The flow fields, needed for species transport, are constructed using inverse distance weighted polynomial interpolation techniques that map routine monitoring data onto a regular computational mesh. Variational analysis procedures are then employed to adjust the field so that mass is conserved. Initial concentration and mixing height distributions can be established with the same interpolation algorithms. Subgrid scale turbulent transport is characterized by a gradient diffusion hypothesis. Similarity solutions are used to model the surface layer fluxes. Above this layer different treatments of turbulent diffusivity are required to account for variations in atmospheric stability. Convective velocity scaling is utilized to develop eddy diffusivities for unstable conditions. The predicted mixing times are in accord with results obtained during sulfur hexafluoride (SF(,6)) tracer experiments. Conventional models are employed for neutral and stable conditions. A new formulation for gaseous deposition fluxes is presented that provides a means for estimating removal rates as a function of atmospheric stability. The model satisfactorily reproduces measured deposition velocities for reactive materials. In addition it is shown how computational cell size influences the representation of surface removal. Chemical interactions between twenty nine chemical species are described by a 52 step kinetic mechanism. The atmospheric hydrocarbon chemistry is modeled by the reactions of six lumped classes: alkanes, ethylene, other olefins, aromatics, formaldehyde and other aldehydes; a grouping that enables representation of a wide range of smog chamber experiments and atmospheric conditions. Chemical lumping minimizes the number of species while maintaining a high degree of detail for the inorganic reactions. Variations in rate data, stoichiometric coefficients and initial conditions have been studied using the Fourier Amplitude Sensitivity Test. The wide variation in time scales, non-linearity of the chemistry and differences in transport processes complicates selection of numerical algorithms. Operator splitting techniques are used to decompose the governing equation into elemental steps of transport and chemistry. Each transport operator is further split into advective and diffusive components so that linear finite element and compact finite difference schemes can be applied to their best advantage. Because most of the computer time is consumed by the chemical kinetics those species that could be accurately described by pseudo-steady state approximations were identified reducing the number of species, described by differential equations, to 15. While the mathematical formulation of the complete system contains no regional or area specific information, performance evaluation studies were carried out using data measured in the South Coast Air Basin of Southern California. Detailed emissions and meteorological information were assembled for the period 26-28 June 1974. A comparison between predictions and observed air quality, during multi-day periods, indicates that the model can

  5. Models for human exposure to air pollution

    International Nuclear Information System (INIS)

    Four models for human exposure to air pollution are discussed and compared. Simple microenvironment monitoring measures pollutant concentrations at fixed locations, regarded as proxies for similar locations or microenvironments. This model does not require pollutant measurements on the individual level, therefore is easy to implement. However, the model can be used only to estimate the average exposure in a population and does not provide any estimate of the variability and distribution of individual exposures. Replicated microenvironment monitoring provides some estimates of the variability and distribution. However, because of the possible discrepancy between the microenvironment concentration distribution and the individual concentration distribution, some adjustment might be necessary. Integrated personal monitoring allows direct estimation of the average exposure as well as the variability and distribution of individual exposures. Coupled with the appropriate time budget data, a regression analysis can be applied to estimate the contribution from each microenvironment type

  6. Variation of the air crew exposure to cosmic radiation.

    Czech Academy of Sciences Publication Activity Database

    Spurný, František; Malušek, Alexandr

    Versailles : WONUC, 1999. s. 27. [The effects of low and very low doses of ionizing radiation on human health. 16.06.1999-18.06.1999, Versailles ] Subject RIV: DN - Health Impact of the Environment Quality

  7. Seeing the invisible: Direct visualization of therapeutic radiation beams using air scintillation

    International Nuclear Information System (INIS)

    Purpose: To assess whether air scintillation produced during standard radiation treatments can be visualized and used to monitor a beam in a nonperturbing manner. Methods: Air scintillation is caused by the excitation of nitrogen gas by ionizing radiation. This weak emission occurs predominantly in the 300–430 nm range. An electron-multiplication charge-coupled device camera, outfitted with an f/0.95 lens, was used to capture air scintillation produced by kilovoltage photon beams and megavoltage electron beams used in radiation therapy. The treatment rooms were prepared to block background light and a short-pass filter was utilized to block light above 440 nm. Results: Air scintillation from an orthovoltage unit (50 kVp, 30 mA) was visualized with a relatively short exposure time (10 s) and showed an inverse falloff (r2 = 0.89). Electron beams were also imaged. For a fixed exposure time (100 s), air scintillation was proportional to dose rate (r2 = 0.9998). As energy increased, the divergence of the electron beam decreased and the penumbra improved. By irradiating a transparent phantom, the authors also showed that Cherenkov luminescence did not interfere with the detection of air scintillation. In a final illustration of the capabilities of this new technique, the authors visualized air scintillation produced during a total skin irradiation treatment. Conclusions: Air scintillation can be measured to monitor a radiation beam in an inexpensive and nonperturbing manner. This physical phenomenon could be useful for dosimetry of therapeutic radiation beams or for online detection of gross errors during fractionated treatments

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

    DEFF Research Database (Denmark)

    Yin, Chungen

    2013-01-01

    Radiation is the principal mode of heat transfer in utility boiler furnaces. Models for radiative properties play a vital role in reliable simulations of utility boilers and simulation-based design and optimization. The weighted sum of gray gases model (WSGGM) is one of the most widely used models 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 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 accuracy, completeness, and implementation and demonstrates the use and impacts of the refined model in CFD simulation of a conventional air-fuel utility boiler. The refined model is found to make a remarkable difference from the existing models in CFD results, when the particle?radiation interaction is negligible and not taken into account (e.g., in gaseous fuel combustion). Comparatively, the impacts of the refined model are greatly compromised under a solid-fuel combustion scenario because of the important role of the particle?radiation interaction. As the conclusion, the refined air-fuel WSGGM is highly recommended for use in CFD simulation of any air-fuel combustion process because of its greater accuracy, completeness, and applicability.

  9. 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...

  10. Filamentation of femtosecond radiation from a Cr:forsterite laser in air

    International Nuclear Information System (INIS)

    The filamentation of radiation from a 1.24-?m femtosecond Cr:forsterite laser in air is studied experimentally and theoretically. The decrease in the laser beam diameter during filamentation was observed. The parameters of filaments produced by radiation from a Cr:forsterite and a Ti:sapphire lasers are compared. It is shown that a filament produced by radiation from the Cr:forsterite laser appears at a larger distance and contains more energy than a filament produced by radiation from the Ti:sapphire laser with the same initial parameters of pulses. (femtosecond filaments)

  11. AIRFLY: Measurement of the air fluorescence radiation induced by electrons.

    Czech Academy of Sciences Publication Activity Database

    Arciprete, F.; Bohá?ová, Martina; Bluemer, J.; Caruso, R.; Di Carlo, P.; Doubrava, M.; Esposito, A.; Facal, P.; Fauth, A.C.; Goletti, C.; Hrabovský, Miroslav; Kemp, E.; Klages, H.O.; Kleifges, M.; Klepser, S.; Matthiae, G.; Mazzitelli, G.; Nožka, Libor; Nogima, H.; Palatka, Miroslav; Petrera, S.; Privitera, P.; Prosposito, P.; ?ídký, Jan; Schovánek, Petr; Vacek, V.; Ulrich, A.; Verzi, V.; Waldenmaier, T.

    2006-01-01

    Ro?. 150, - (2006), s. 186-189. ISSN 0920-5632 R&D Projects: GA ?R(CZ) GA202/05/2470 Institutional research plan: CEZ:AV0Z10100502 Keywords : cosmic rays * air fluorescence * linear accelerators Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 0.875, year: 2005

  12. Simulating aerosol-radiation-cloud feedbacks on meteorology and air quality over eastern China under severe haze conditionsin winter

    Science.gov (United States)

    Zhang, B.; Wang, Y.; Hao, J.

    2015-03-01

    The aerosol-radiation-cloud feedbacks on meteorology and air quality over eastern China under severe winter haze conditions in January 2013 are simulated using the fully coupled online Weather Research and Forecasting/Chemistry (WRF-Chem) model. Three simulation scenarios including different aerosol configurations are undertaken to distinguish the aerosol's radiative (direct and semi-direct) and indirect effects. Simulated spatial and temporal variations of PM2.5 are generally consistent with surface observations, with a mean bias of -18.9 ?g m-3 (-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 m-2, 3.2°C, 0.8 m s-1, and 268 m, respectively. The simulated impact of the aerosol indirect effects is comparatively smaller. Through reducing the PBL height and stabilizing lower atmosphere, the aerosol effects lead to increases in surface concentrations of primary pollutants (CO and SO2). Surface O3 mixing ratio is reduced by up to 6.9 ppb (parts per billion) due to reduced incoming solar radiation and lower temperature, while the aerosol feedbacks on PM2.5 mass concentrations show some spatial variations. 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.

  13. Near-Earth Space Radiation Models

    Science.gov (United States)

    Xapsos, Michael A.; O'Neill, Patrick M.; O'Brien, T. Paul

    2012-01-01

    Review of models of the near-Earth space radiation environment is presented, including recent developments in trapped proton and electron, galactic cosmic ray and solar particle event models geared toward spacecraft electronics applications.

  14. 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.

  15. Performance Analysis and Air Flow Optimization of Radiator Using Simulation

    Directory of Open Access Journals (Sweden)

    K.Ganesan*,

    2014-10-01

    Full Text Available Automotive engine cooling system takes care of excess heat produced during engine operation. It Regulates Engine surface temperature for engine optimum efficiency. Recent advancement in engine for power forced engine cooling system to develop new strategies to improve its radiator performance efficiency. Also to reduce fuel consumption along with controlling engine emission to indicated environmental pollution norms. This paper throws light on parameters optimization flow changes analysis which influences radiator performance along with reviews some of the systematically with new modern approaches to enhance radiator performance analysis with design and numerical analysis of water heating conductivity to transient analysis single sample tube in different copper graded material analysis in flow passing through the water comparing to the better cost effective and material data its analyzed using in ansys 14.5 version.

  16. 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.

  17. 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.)

  18. Mesoscale air pollution dispersion models—I. Eulerian grid model

    Science.gov (United States)

    van Egmond, N. D.; Kesseboom, H.

    To support the data interpretation of the dense air pollution monitoring network in The Netherlands, two numerical models were developed which describe the air pollution transport over the 400 km × 400 km area around the country. The models are designed for efficient, operational applications on a mini-computer system and require only limited sets of input data. The Eulerian GRID model, described in this paper, is based on the pseudo-spectral advection scheme for a 32 × 32 grid with a gridsize of 15km. Vertical stratification in a surface, mixing and reservoir layer enables an adequate description of the temporal variability of concentrations. Spatial correlations between measured and modelled SO 2 concentrations are moderate. Some lack of correlation is ascribed to inaccuracies in foreign emission data rather than the degree of meteorological sophistication.

  19. Radiofrequency radiation: safe working practices in the Royal Australian Air Force

    International Nuclear Information System (INIS)

    The Royal Australian Air Force (RAAF) has long recognised the value of its work force and the need to preserve their health and wellbeing to achieve operational objectives. The Directorate of Air Force Safety (DAFS) is required by the Chief of the Air Staff to take all measures possible to prevent accidents and incidents in the RAAF, under the provisions of the Defence Instruction, 'Air Force Safety and Occupational Health Policy'. Consequently, the RAAF has exercised a pragmatic approach to radiofrequency radiation (RFR) and has always adopted and implemented strict exposure standards. DAFS receives technical advice on RFR from the Directorate of Telecommunications Engineering (DTELENG) and on occupational health from the Directorate General of Air Force Health Services (DGAFHS)

  20. Dark radiation confronting LHC in Z ' models

    OpenAIRE

    Solaguren-beascoa, A.; Gonzalez-garcia, M. C.

    2013-01-01

    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 al...

  1. Performance Analysis and Air Flow Optimization of Radiator Using Simulation

    OpenAIRE

    K.Ganesan*,; Ravikumar, P.

    2014-01-01

    Automotive engine cooling system takes care of excess heat produced during engine operation. It Regulates Engine surface temperature for engine optimum efficiency. Recent advancement in engine for power forced engine cooling system to develop new strategies to improve its radiator performance efficiency. Also to reduce fuel consumption along with controlling engine emission to indicated environmental pollution norms. This paper throws light on parameters optimization flow chan...

  2. 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; Nun?ez, 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 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 o...

  3. Air

    Science.gov (United States)

    ... to protect yourself from dirty air . Indoor air pollution and outdoor air pollution Air can be polluted indoors and it can ... comes from the natural breakdown of uranium in soil, rock, and water and gets into the air ...

  4. AIRFLY: Measurement of the Air Fluorescence Radiation Induced by Electrons

    International Nuclear Information System (INIS)

    The AIRFLY (AIR FLuorescence Yield) experiment objective is the precise measurement of the fluorescence yield in atmospheric gases. AIRFLY takes data at the Beam Test Facility of the INFN Laboratori Nazionali di Frascati. A first test performed on the beam line has allowed to verify the feasibility of the physics program which includes an absolute measurement of the fluorescence yield with a precision better than 5%, the measurement of the spectrum and of the yield dependence on the electron energy, gas pressure, temperature and composition. Details of the experimental apparatus and preliminary results from the test are reported

  5. AIRFLY: Measurement of the Air Fluorescence Radiation Induced by Electrons

    Energy Technology Data Exchange (ETDEWEB)

    Arciprete, F.; Goletti, C.; Matthiae, G.; Privitera, P.; Prosposito, P.; Salina, G.; Verzi, V. [University of Rome Tor Vergata and Sezione INFN di Roma II (Italy); Bohacova, M. [Inst. of Physics, Czech Academy of Science (Czech Republic); Bluemer, J. [University of Karlsruhe (Germany)]|[Forschungszentrum Karlsruhe (Germany); Bollmann, E. [Forschungszentrum Karlsruhe (Germany); Caruso, R. [INFN and Physics Department, L' Aquila University (Italy); Di Carlo, P. [INFN and Physics Department, L' Aquila University (Italy); Doubrava, M. [Czech Technical University (Czech Republic); Esposito, A. [Laboratori Nazionali di Frascati dell' INFN (Italy); Facal, P. [University of Rome Tor Vergata and Sezione INFN di Roma II (Italy); Fauth, A.C. [Universidade Estadual de Campinas, Brasil (Brazil); Hrabovsky, M. [Joint Laboratory of Optics of PU and Inst. of Physics AS CR (Czech Republic); Kemp, E. [Universidade Estadual de Campinas (Brazil); Klages, H.O.; Kleifges, M. [Forschungszentrum Karlsruhe (Germany); Klepser, S. [University of Karlsruhe (Germany); Iarlori, M. [INFN and Physics Department, L' Aquila University (Italy); Mazzitelli, G. [Laboratori Nazionali di Frascati dell' INFN (Italy); Nogima, H. [Universidade Estadual de Campinas, Brasil (Brazil); Nozka, L. [Joint Laboratory of Optics of PU and Inst. of Physics AS CR (Czech Republic); Palatka, M. [Joint Laboratory of Optics of PU and Inst. of Physics AS CR (Czech Republic); Petrera, S. [INFN and Physics Department, L' Aquila University (Italy); Ridky, J. [Inst. of Physics, Czech Academy of Science (Czech Republic); Rizi, V. [INFN and Physics Department, L' Aquila University (Italy); Schovanek, P. [Joint Laboratory of Optics of PU and Inst. of Physics AS CR (Czech Republic); Ulrich, A. [Munich Technical University (Germany); Vacek, V. [Czech Technical University (Czech Republic); Valente, P. [Laboratori Nazionali di Frascati dell' INFN (Italy); Waldenmaier, T. [Forschungszentrum Karlsruhe (Germany)

    2006-01-15

    The AIRFLY (AIR FLuorescence Yield) experiment objective is the precise measurement of the fluorescence yield in atmospheric gases. AIRFLY takes data at the Beam Test Facility of the INFN Laboratori Nazionali di Frascati. A first test performed on the beam line has allowed to verify the feasibility of the physics program which includes an absolute measurement of the fluorescence yield with a precision better than 5%, the measurement of the spectrum and of the yield dependence on the electron energy, gas pressure, temperature and composition. Details of the experimental apparatus and preliminary results from the test are reported.

  6. 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.

  7. 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

    Sá?ka, O.; Melymuk, L.; ?upr, P.; Dvorská, Alice; Klánová, J.

    2014-01-01

    Ro?. 90, oct (2014), s. 88-95. ISSN 1352-2310 Institutional support: RVO:67179843 Keywords : passive air sampling * air dispersion modeling * GIS * polycyclic aromatic hydrocarbons * emission inventories Subject RIV: DI - Air Pollution ; Quality Impact factor: 3.062, year: 2013

  8. 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.

  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. 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.

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

    OpenAIRE

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

    2011-01-01

    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 concentra...

  12. ATTENUATION OF SOLAR UV RADIATION BY AEROSOLS DURING AIR POLLUTION EPISODES

    Science.gov (United States)

    Increase in the amount of solar UV radiation reaching the surface due to decrease in stratospheric ozone continues to be a major concern (WMO, 1998). However, recent studies show that absorption and smattering by aerosols during air pollution episode decreases the amount of radi...

  13. Experimental study of nuclear reactor's neutron and gamma-radiation of scattering in the air

    International Nuclear Information System (INIS)

    Comprehensive experimental data on scattered neutron and gamma-radiations distribution from RA and IVG.1M reactors in the air on distances from 50 to 1000 m are obtained. During the experiments the wide set of detectors, including dosimetric, radiometric and spectrometric instruments were used. These data will be used for verification of calculation codes and checking of the group nuclear constants

  14. 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

  15. 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.

  16. 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

    Scientific Electronic Library Online (English)

    Cláudio R. da, Silva; Valdiney J. da, Silva; José, Alves Júnior; Hudson de P., Carvalho.

    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 n [...] ove 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. Abstract in english 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.

  17. KREAM: Korean Radiation Exposure Assessment Model for Aviation Route Dose

    Science.gov (United States)

    Hwang, J.; Dokgo, K.; Choi, E. J.; Kim, K. C.; Kim, H. P.; Cho, K. S. F.

    2014-12-01

    Since Korean Air has begun to use the polar route from Seoul/ICN airport to New York/JFK airport on August 2006, there are explosive needs for the estimation and prediction against cosmic radiation exposure for Korean aircrew and passengers in South Korea from public. To keep pace with those needs of public, Korean government made the law on safety standards and managements of cosmic radiation for the flight attendants and the pilots in 2013. And we have begun to develop our own Korean Radiation Exposure Assessment Model (KREAM) for aviation route dose since last year funded by Korea Meteorological Administration (KMA). GEANT4 model and NRLMSIS 00 model are used for calculation of the energetic particles' transport in the atmosphere and for obtaining the background atmospheric neutral densities depending on altitude. For prediction the radiation exposure in many routes depending on the various space weather effects, we constructed a database from pre-arranged simulations using all possible combinations of R, S, and G, which are the space weather effect scales provided by the National Oceanic and Atmospheric Administration (NOAA). To get the solar energetic particles' spectrum at the 100 km altitude which we set as a top of the atmospheric layers in the KREAM, we use ACE and GOES satellites' proton flux observations. We compare the results between KREAM and the other cosmic radiation estimation programs such as CARI-6M which is provided by the Federal Aviation Agency (FAA). We also validate KREAM's results by comparison with the measurement from Liulin-6K LET spectrometer onboard Korean commercial flights and Korean Air Force reconnaissance flights.

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

    DEFF Research Database (Denmark)

    Ketzel, Matthias; Berkowicz, Ruwim

    2011-01-01

    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 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.

  19. 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 ?g/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.

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

    Directory of Open Access Journals (Sweden)

    B. Zhang

    2014-10-01

    Full Text Available 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 ?g m?3 (?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 m?2, 3.2 °C, 0.8 m s?1, 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's performances 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.

  1. 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.

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

    Science.gov (United States)

    Geints, Yu E.; Zemlyanov, A. A.

    2014-09-01

    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 ?m. 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.

  3. A physical approach to air pollution climatological modelling in a complex site

    International Nuclear Information System (INIS)

    A Gaussian climatological model which takes into account physical factors affecting air pollutant dispersion, such as nocturnal radiative inversion and mixing height evolution, associated with land breeze and sea breeze regimes, respectively, has been applied to the topographically complex area of La Spezia (a basin surrounded by hilly terrain, located on the Italian coast). Results from the measurements of the dynamic and thermodynamic structure of the lower atmosphere, obtained by a series of field experiments, are utilized in the model to calculate SO2 seasonal average concentrations. The model has been tested on eight three-monthly periods by comparing the simulated values with the ones measured at the SO2 stations of the local air pollution monitoring network. Comparison of simulated and measured values was very satisfactory and proved the applicability of the implemented model for urban planning and establishment of air quality strategies also at a topographically complex site. (author)

  4. Influences of atmospheric conditions and air mass on the ratio of ultraviolet to total solar radiation

    Energy Technology Data Exchange (ETDEWEB)

    Riordan, C.J.; Hulstrom, R.L.; Myers, D.R.

    1990-08-01

    The technology to detoxify hazardous wastes using ultraviolet (UV) solar radiation is being investigated by the DOE/SERI Solar Thermal Technology Program. One of the elements of the technology evaluation is the assessment and characterization of UV solar radiation resources available for detoxification processes. This report describes the major atmospheric variables that determine the amount of UV solar radiation at the earth's surface, and how the ratio of UV-to-total solar radiation varies with atmospheric conditions. These ratios are calculated from broadband and spectral solar radiation measurements acquired at SERI, and obtained from the literature on modeled and measured UV solar radiation. The following sections discuss the atmospheric effects on UV solar radiation and provide UV-to-total solar radiation ratios from published studies, as well as measured values from SERI's data. A summary and conclusions are also given.

  5. 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

  6. Propagation speed of {gamma}-radiation in air

    Energy Technology Data Exchange (ETDEWEB)

    Cavalcante, Jose T.P.D.; Silva, Paulo R.J.; Saitovitch, Henrique [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Macedo Junior, Marcelo A.V. [Centro Federal de Educacao Tecnologica de Quimica de Nilopolis (CEFET), RJ (Brazil)

    2008-07-01

    To perform such measurements the availability of a gamma radiation source in which two {gamma}-rays are emitted simultaneously in opposite directions -as already used(5,6) as well as applied in the present case- turns out to be essential to the feasibility of the experiment, as far as no reflection techniques could be used. Such suitable source was the positron emitter {sup 22}Na placed in a metal container in which the positrons are stopped and annihilated when reacting with the medium electrons, in such way originating -as it is very well established from momentum/energy conservation laws(7)- two {gamma}-rays, energy 511 KeV each, both emitted simultaneously in opposite directions. In all these previous experiments were used photomultiplier detectors coupled to NaI(Tl) crystal scintillators, which have a good energy resolution but a deficient time resolution for such purposes. Presently, as an innovatively improvement, were used BaF{sub 2} and CsF crystal scintillators which display a much better time resolution. (author)

  7. Generalized additive model of air pollution to daily mortality

    International Nuclear Information System (INIS)

    The association of air pollution with daily mortality due to cardiovascular disease, respiratory disease, and old age (65 or older) in Seoul, Korea was investigated in 1999 using daily values of TSP, PM10, O3, SO2, NO2, and CO. Generalized additive Poisson models were applied to allow for the highly flexible fitting of daily trends in air pollution as well as nonlinear association with meteorological variables such as temperature, humidity, and wind speed. To estimate the effect of air pollution and weather on mortality, LOESS smoothing was used in generalized additive models. The findings suggest that air pollution levels affect significantly the daily mortality. (orig.)

  8. Radioactive contamination monitoring of air and emergency response, procedure of the radiation protection section

    International Nuclear Information System (INIS)

    Full text: The Radiation Protection Section has planned procedures in place in the event of an emergency dealing with loose radioactive material. During the clean-up, radiation dose must be monitored. Air sampling is important. It can be used during a radiological emergency to estimate committed dose from inhaled radioactive dusts. Radioactive material concentration, in Bq/m3, obtained from air sampling is converted to committed dose by using an appropriate dose conversion factor, in units of Sv/Bq, in International Atomic Energy Agency's basic safety series number 115 called International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources. A single dose conversion factor will be used for uranium and thorium series, in the field to estimate committed dose without the need for an extensive calculation. During an emergency, operations will be busy and hectic and using an approximate number for this will be much easier to deal with. This will give an idea of exposure level and the risk associated with this exposure. The procedure may also be used to estimate committed dose during spillage of any radioactive material. An air sampling procedure will be discussed during the presentation. Other procedures will be included for an emergency response situation.

  9. 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)

  10. 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)

  11. Radiation Dosimetry Experiment (RaD-X): High-Altitude Balloon Flight Mission for Improving the Nairas Aviation Radiation Model

    Science.gov (United States)

    Mertens, C. J.

    2014-12-01

    The NASA Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) model is a real-time, global, physics-based model for predicting exposure to cosmic radiation to air travelers from both galactic and solar sources. Tabular and graphical data products from the prototype operational NAIRAS model have been available to the public since April 2011. An initial validation of the NAIRAS model was recently conducted by comparing predicted dose rates with tabulated reference aircraft measurement data and recent aircraft radiation measurements taken in 2008. However, aircraft measurements alone do not provide an unambiguous constraint on the model such that the predominant source of uncertainty in the NAIRAS model could be uniquely identified. High altitude measurements above the Pfotzer maximum are needed to characterize the extent to which the NAIRAS model can predict the cosmic radiation primaries, which are the source of the secondary particles that are responsible for radiation exposure at aircraft flight altitudes. The Radiation Dosimetry Experiment (RaD-X) is a NASA high-altitude balloon flight mission with the goal of improving model characterization of cosmic radiation primaries by taking dosimetric measurements above the Pfotzer maximum. A second goal of the RaD-X mission is to facilitate the pathway toward data assimilative predictions of atmospheric cosmic radiation exposure by identifying and characterizing low-cost radiation measurement solutions. RaD-X is scheduled for launch at Fort Sumner, NM in September 2015. Here we briefly describe the NAIRAS model, present the science and mission overview of the RaD-X mission, and show preliminary results from instrument beam tests and calibration.

  12. Nuclide Identification of Gamma Ray Energy Peaks from an Air Sample for the Emergency Radiation Monitoring

    International Nuclear Information System (INIS)

    For the emergency radiation monitoring using gamma spectrometry, we should sufficiently survey the background spectra as environmental samples with systematic nuclide identification method. In this study, we obtained the gamma ray energy spectrum using a HPGe gamma spectrometry system from an air sample. And we identified nuclide of the gamma ray energy peaks in the spectrum using two methods -1) Half life calculation and 2) survey for cascade coincidence summing peaks using nuclear data. As the results, we produced the nuclide identification results for the air sample

  13. 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...

  14. FUZZY MODELLING OF LIQUID DESICCANT BASED AIR DEHUMIDIFICATION SYSTEM

    OpenAIRE

    Harpreet Singh; Jagdev Singh,; Simranpreet Singh Gill

    2011-01-01

    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...

  15. 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.

  16. Radiative torques: Analytical Model and Basic Properties

    OpenAIRE

    Lazarian, Alex; Hoang, Thiem

    2007-01-01

    We attempt to get a physical insight into grain alignment processes by studying basic properties of radiative torques (RATs). For this purpose we consider a simple toy model of a helical grain that reproduces well the basic features of RATs. The model grain consists of a spheroidal body with a mirror attached at an angle to it. Being very simple, the model allows analytical description of RATs that act upon it. We show a good correspondence of RATs obtained for this model an...

  17. Inflation in a modified radiative seesaw model

    OpenAIRE

    Budhi, Romy H. S.; Kashiwase, Shoichi; Suematsu, Daijiro

    2015-01-01

    The existence of the inflationary era in the early Universe seems to be strongly supported by recent CMB observations. However, only a few realistic inflation scenarios which have close relation to particle physics seem to have been known unfortunately. The radiative neutrino mass model with inert doublet dark matter is a promising model for the present experimental issues which cannot be explained within the standard model. In order to make the model include inflation, we e...

  18. Data assimilation for air quality models

    DEFF Research Database (Denmark)

    Silver, Jeremy David

    2014-01-01

    The chemical composition of the Earth’s atmosphere has major ramifications for not only human health, but also biodiversity and the climate; hence there are scientific, environmental and societal interests in accurate estimates of atmospheric chemical composition and in understanding the governing 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 higher uncertainties. It is possible, however, to combine information from measurements and models to moreaccurately estimate the state of the atmosphere using a statistically consistent framework known as “data assimilation”. In this study, three data assimilation schemes are implemented and evaluated. The data assimilation schemes are coupled to the Danish Eulerian Hemispheric Model (DEHM), a large-scale three-dimensional off-line CTM, and the data ingested were retrievals of atmospheric composition from polar-orbiting satellites. The three assimilation techniques applied were: a three-dimensional optimal interpolation procedure (OI), an Ensemble Kalman Filter (EnKF), and a three-dimensional variational scheme (3D-var). The three assimilation procedures are described and tested. A multi-faceted approach is taken for the verification, using independent measurements from surface air-quality monitoring stations, satellite retrievals of atmospheric chemical composition and comparison with idealised simulations. The 3D-var and EnKF schemes are capable of performing multi-species adjustments, meaning that observations of different chemical components can be assimilated simultaneously. Furthermore, 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 of the 3D-var and EnKF schemes are expanded to assess the potential benefits of joint multi-species adjustments (c.f. adjusting individual species independently) or direct adjustment of unobserved species.

  19. Mathematical Models for Microbial Kill by Radiation

    International Nuclear Information System (INIS)

    A model is proposed based on the known radiation effects and genetic structures of the microorganisms, which leads to ND = N0 (1 -(1 - eD/D1)r)s. It is shown that this equation fits the experimental data very well. The physical theory for radiation effects is compared with the experimental results. It is suggested that repair plays a very dominant role and that the genetic material in the resistant microbes exists in multiples. (author)

  20. MODELED MESOSCALE METEOROLOGICAL FIELDS WITH FOUR-DIMENSIONAL DATA ASSIMILATION IN REGIONAL SCALE AIR QUALITY MODELS

    Science.gov (United States)

    This paper addresses the need to increase the temporal and spatial resolution of meteorological data currently used in air quality simulation models, AQSMs. ransport and diffusion parameters including mixing heights and stability used in regulatory air quality dispersion models a...

  1. Urban Air Quality Modelling with AURORA: Prague and Bratislava

    Science.gov (United States)

    Veldeman, N.; Viaene, P.; De Ridder, K.; Peelaerts, W.; Lauwaet, D.; Muhammad, N.; Blyth, L.

    2012-04-01

    The European Commission, in its strategy to protect the health of the European citizens, states that in order to assess the impact of air pollution on public health, information on long-term exposure to air pollution should be available. Currently, indicators of air quality are often being generated using measured pollutant concentrations. While air quality monitoring stations data provide accurate time series information at specific locations, air quality models have the advantage of being able to assess the spatial variability of air quality (for different resolutions) and predict air quality in the future based on different scenarios. When running such air quality models at a high spatial and temporal resolution, one can simulate the actual situation as closely as possible, allowing for a detailed assessment of the risk of exposure to citizens from different pollutants. AURORA (Air quality modelling in Urban Regions using an Optimal Resolution Approach), a prognostic 3-dimensional Eulerian chemistry-transport model, is designed to simulate urban- to regional-scale atmospheric pollutant concentration and exposure fields. The AURORA model also allows to calculate the impact of changes in land use (e.g. planting of trees) or of emission reduction scenario's on air quality. AURORA is currently being applied within the ESA atmospheric GMES service, PASODOBLE (http://www.myair-eu.org), that delivers information on air quality, greenhouse gases, stratospheric ozone, … At present there are two operational AURORA services within PASODOBLE. Within the "Air quality forecast service" VITO delivers daily air quality forecasts for Belgium at a resolution of 5 km and for the major Belgian cities: Brussels, Ghent, Antwerp, Liege and Charleroi. Furthermore forecast services are provided for Prague, Czech Republic and Bratislava, Slovakia, both at a resolution of 1 km. The "Urban/regional air quality assessment service" provides urban- and regional-scale maps (hourly resolution) for air pollution and human exposure statistics for an entire year. So far we concentrated on Brussels, Belgium and the Rotterdam harbour area, The Netherlands. In this contribution we focus on the operational forecast services. Reference Lefebvre W. et al. (2011) Validation of the MIMOSA-AURORA-IFDM model chain for policy support: Modeling concentrations of elemental carbon in Flanders, Atmospheric Environment 45, 6705-6713

  2. 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

  3. Optical, radio and x-ray radiation of red sprites produced by runaway air breakdown

    Energy Technology Data Exchange (ETDEWEB)

    Yukhimuk, V.; Roussel-Dupre, R.; Symbalisty, E.; Taranenko, Y.

    1997-04-01

    The authors use the runaway air breakdown model of upward discharges to calculate optical, radio, and X-ray radiation generated by red sprites. Red sprites are high altitude (up to 90 km) lightning discharges. Aircraft based observations show that sprites are predominantly red in color at altitudes above {approximately}55 km with faint blue tendrils, which extend downward to an altitude of 40 km; the duration of a single sprite is less than 17 ms, their maximum brightness is about 600 kR, and estimated total optical energy is about 1--5 kJ per event. The ground based observations show similar results, and provide some additional information on spatial and temporal structure of sprites, and on sprite locations. One difference between aircraft and ground-based observations is that blue tendrils are rarely observed from the ground. Sprites usually occur above the anvils of large mesoscale convective systems and correlate with strong positive cloud to ground discharge. Upward discharges are the most probable source of X-ray emission observed above large thunderstorm complexes by the Compton Gamma-ray Observatory. To escape the atmosphere these {gamma}-rays must originate above 25 km altitude. Red sprites are usually observed at altitudes higher than 50 km, and are therefore a likely source of this x-ray emission.

  4. 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.

  5. Modeling radiation effects at the tissue level

    Science.gov (United States)

    Müller, M.; Durante, M.; Stöcker, H.; Merz, F.; Bechmann, I.

    2010-10-01

    For the understanding of radiation action in humans, a synergistic approach of experiments and quantitative modeling of working hypotheses is necessary. A large set of experimental data at the single-cell level are available, and biophysical modeling of radiation action has so far mostly concentrated on the first phases of radiation interaction with the biomolecules, and later biochemical stages including DNA breakage, repair, and the formation of chromosomal aberrations. The models can be extended to cell killing and transformation, but so far still using a single-cell (clonal expansion) approach. On the contrary, new experimental evidence points to the microenvironment and the tissue level as a critical radiation target for late effects, and to epigenetic and signaling mechanisms as mediators of radiation damage. This higher structural level is generally ignored in modeling, owing to its complexity and to the lack of experimental data. In this paper we will highlight the requirements for specific experimental approaches targeting the tissue/microenvironment level and the most promising available experimental models.

  6. The air radiation dose unit investigation method in the village of Iitate

    International Nuclear Information System (INIS)

    Radioactive contamination caused by the nuclear accident were to release large amounts of radioactive material by the Tohoku-Pacific Ocean Earthquake, the Kanto region are ranging widely not only in the Northeast as well as the surrounding area. I am currently work is proceeding decontamination countries and local governments have been made in the same uniform survey Soil Contamination Countermeasures Act without investigating the detailed distribution of the radioactive material. Radioactive material because it is spread by geological agency, the distribution varies depending on the topographical and geological conditions. Determination of air radiation dose is measured at a height of 1 m above the ground. Air radiation dose measurement is important in order to reveal the distribution of radioactive material in a wide area in the measure of radioactive materials. If fact, measured in the area that is contaminated with high concentrations of radioactive material, with the result that the height measured at the earth surface and 1 m it was very different. Measurements of the surface earth to clarify the presence of radioactive material in more detail, is higher than the measured value detected by the high 1 m. It is considered to have been influenced by the surface geology, vegetation, and microtopography, radiation dose space has measure radiation dose space from all directions, the radiation dose space on the surface of the earth radioactive piled up on the ground considered because it is dominated by the material shall be measured on the ground surface shows the distribution of radioactive material from Contamination survey radioactive material in a wide range, cheap, fast is important, and reproducible method of investigation and a field type. It is important to note that, to check whether the radioactive material has been moved to a depth below the ground surface which is a paramount concern measures radioactive contamination. Method of measuring space radiation dose survey team conducted Fukushima has adopted a method of measuring while shielding such as lead, while digging in the ground surface and space dosimetry of land surface and a height of 1 m above ground. As for this investigation method, the measurement relatively analyzes air radiation dose while being affected by the outskirts as the air radiation dose unit investigation method by the investigation method according to the geo-stratigraphic unit investigation method. (author)

  7. MOS modeling hierarchy including radiation effects

    International Nuclear Information System (INIS)

    A hierarchy of modeling procedures has been developed for MOS transistors, circuit blocks, and integrated circuits which include the effects of total dose radiation and photocurrent response. The models were developed for use with the SCEPTRE circuit analysis program, but the techniques are suitable for other modern computer aided analysis programs. The modeling hierarchy permits the designer or analyst to select the level of modeling complexity consistent with circuit size, parametric information, and accuracy requirements. Improvements have been made in the implementation of important second order effects in the transistor MOS model, in the definition of MOS building block models, and in the development of composite terminal models for MOS integrated circuits

  8. Health physics experience in commissioning and operation of radiation and air activity monitoring system at FBTR

    International Nuclear Information System (INIS)

    The Radiation and Air Activity Monitoring System (RAAMS) at Fast Breeder Test Reactor (FBTR) is meant to monitor and record the radiation and air activity levels at various potentially active areas in FBTR complex. Health Physics Group, FBTR was associated during commissioning of RAAMS in fixing the alarm settings for the monitors, their relocation and in formulating the surveillance procedures. The areas were surveyed to check for any release of activity for confirming the observed readings during operation of the reactor. In such cases, augmentation of shielding was recommended and was promptly implemented by the station management. The details of the long and fruitful experience gained by the Health Physics Group, FBTR are described in this paper. (author)

  9. Improvement of local air coolers model in ISAAC

    International Nuclear Information System (INIS)

    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

  10. 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

  11. 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.

  12. 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)

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

    Science.gov (United States)

    Sá?ka, Ond?ej; Melymuk, Lisa; ?upr, Pavel; Dvorská, Alice; Klánová, Jana

    2014-10-01

    This study introduces a new combined air concentration measurement and modeling approach that we propose can be useful in medium and long term air quality assessment. A dispersion study was carried out for four high molecular weight polycyclic aromatic hydrocarbons (PAHs) in an urban area with industrial, traffic and domestic heating sources. A geographic information system (GIS) was used both for processing of input data as well as visualization of the modeling results. The outcomes of the dispersion model were compared to the results of passive air sampling (PAS). Despite discrepancies between measured and modeled concentrations, an approach combining the two techniques is promising for future air quality assessment. Differences between measured and modeled concentrations, in particular when measured values exceed the modeled concentrations, are indicative of undocumented, sporadic pollutant sources. Thus, these differences can also be useful for assessing and refining emission inventories.

  14. 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 (TiO?) 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 TiO? 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 TiO? 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

  15. 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

  16. Multiple ARMAX modeling scheme for forecasting air conditioning system performance

    International Nuclear Information System (INIS)

    System identification is a procedure to characterize the dynamic behavior of a system, subsystem or individual component from measured data. This paper presents a study on the modeling and parameter identification of air conditioning processes by using the mathematical black box modeling technique, autoregressive moving average exogeneous (ARMAX) structure. A generic multiple input multiple output (MIMO) ARMAX structure of typical air conditioning systems is developed, whose parameters are identified by using the recursive extended least squares (RELS) method. The performance of the model is compared with that of a single input single output (SISO) ARMAX model. A significant component of the determination of an ARMAX model is the selection of an appropriate model order. Models of different orders and the effects of properties are evaluated. Site measurements from an air conditioning system in a building are used for the testing and validation of the models in the study

  17. 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.

  18. 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%.

  19. Air pollution modelling on the street canyon.

    Czech Academy of Sciences Publication Activity Database

    Bezpalcová, Klára; Ja?our, Zbyn?k

    2003-01-01

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

  20. 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–? 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

  1. A FEDERATED PARTNERSHIP FOR URBAN METEOROLOGICAL AND AIR QUALITY MODELING

    Science.gov (United States)

    Recently, applications of urban meteorological and air quality models have been performed at resolutions on the order of km grid sizes. This necessitated development and incorporation of high resolution landcover data and additional boundary layer parameters that serve to descri...

  2. Radiation exposure of the aircrew and passengers on some Czechoslovak air lines

    International Nuclear Information System (INIS)

    According to the ICRP 60 recommendation, the aircrew should be included among workers whose exposure to cosmic radiation is considered to be occupational exposure. This brings about the need for a more precise determination and the mapping of the exposure level on different air routes. The results are presented of measurements performed by the staff of the Institute of Radiation Dosimetry on board of CSA aircraft (TU 154 M and A 310-300 Airbus) in 1991-1992. A number of passive and active devices were used to measure the ionizing and neutron component of cosmic radiation. The results obtained confirm the basic ideas about the influence of various factors on the exposure level. The interpretation of data is discussed in detail, particularly with respect to its possible modification based on new data on particle spectra on board of subsonic civil transport aircraft. (author) 2 tabs., 4 figs., 24 refs

  3. Radiation dose estimates due to air particulate emissions from selected phosphate industry operations

    International Nuclear Information System (INIS)

    The EPA Office of Radiation Programs has conducted a series of studies to determine the radiological impact of the phosphate mining and milling industry. This report describes the efforts to estimate the radiation doses due to airborne emissions of particulates from selected phosphate milling operations in Florida. Two wet process phosphoric acid plants and one ore drying facility were selected for this study. The 1976 Annual Operations/Emissions Report, submitted by each facility to the Florida Department of Environmental Regulation, and a field survey trip by EPA personnel to each facility were used to develop data for dose calculations. The field survey trip included sampling for stack emissions and ambient air samples collected in the general vicinity of each plant. Population and individual radiation dose estimates are made based on these sources of data

  4. 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

  5. Validation of a novel air toxic risk model with air monitoring.

    Science.gov (United States)

    Pratt, Gregory C; Dymond, Mary; Ellickson, Kristie; Thé, Jesse

    2012-01-01

    Three modeling systems were used to estimate human health risks from air pollution: two versions of MNRiskS (for Minnesota Risk Screening), and the USEPA National Air Toxics Assessment (NATA). MNRiskS is a unique cumulative risk modeling system used to assess risks from multiple air toxics, sources, and pathways on a local to a state-wide scale. In addition, ambient outdoor air monitoring data were available for estimation of risks and comparison with the modeled estimates of air concentrations. Highest air concentrations and estimated risks were generally found in the Minneapolis-St. Paul metropolitan area and lowest risks in undeveloped rural areas. Emissions from mobile and area (nonpoint) sources created greater estimated risks than emissions from point sources. Highest cancer risks were via ingestion pathway exposures to dioxins and related compounds. Diesel particles, acrolein, and formaldehyde created the highest estimated inhalation health impacts. Model-estimated air concentrations were generally highest for NATA and lowest for the AERMOD version of MNRiskS. This validation study showed reasonable agreement between available measurements and model predictions, although results varied among pollutants, and predictions were often lower than measurements. The results increased confidence in identifying pollutants, pathways, geographic areas, sources, and receptors of potential concern, and thus provide a basis for informing pollution reduction strategies and focusing efforts on specific pollutants (diesel particles, acrolein, and formaldehyde), geographic areas (urban centers), and source categories (nonpoint sources). The results heighten concerns about risks from food chain exposures to dioxins and PAHs. Risk estimates were sensitive to variations in methodologies for treating emissions, dispersion, deposition, exposure, and toxicity. PMID:21651597

  6. 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.

  7. A Model for Polarization of Pulsar Radiation

    Science.gov (United States)

    Gil, J.; Kijak, J.; Zycki, P.

    1993-05-01

    We discuss single-pulse polarization characteristics of pulsar radiation. We use the Ruderman & Sutherland (1975) spark model as a source of subpulse emission and curvature radiation as the elementary mechanism of pulsar radiation. We also consider a proper geometry of pulsar emission. We demonstrate that numerical simulations reproduce all polarization characteristics observed in single pulses. These characteristics result from the properties of single-particle curvature radiation integrated over a large number of independent sources, interaction of this radiation with electron-positron plasma within a sub- pulse-producing column and a geometry determining the gradient of the Radhakrishnan & Cooke (1969) mean position angle swing. We argue that strong, sense-reversing circular polarization is a natural feature of curvature radiation. A significant circular polarization can be observed at a particular subpulse phase if the gradient of the subpulse envelope is steep enough to preserve the net circular polarization from adjacent sources. We also demonstrate that deviations of single pulse position angle from the average curve are caused by joint propagation and geometrical effects. In the case of the shallow Radhakrishnan and Cooke curve a swing across a subpulse should pass through the average curve at or near the subpulse peak. In the case of steep S-shaped mean position angle curves, an exactly orthogonal jump in subpulse swings can occur. The depolarization of linearly polarized component is due to incoherent superposition of a large number of elementary contributions from different field line planes of the pulsar magnetic field.

  8. Radiative corrections in the standard model

    Science.gov (United States)

    Ma, Ernest

    1981-02-01

    The effects of radiative corrections on the masses of the standard W and Z bosons as well as their decay widths and induced neutral-current couplings are briefly reviewed. In contrast, the model of Berezinsky and Smirnov, where all weak gauge boson masses can be substantially heavier than 100 GeV, is also described.

  9. Radiative corrections in the standard model

    International Nuclear Information System (INIS)

    The effects of radiative corrections on the masses of the standard W and Z bosons as well as their decay widths and induced neutral-current couplings are briefly reviewed. In contrast, the model of Berezinsky and Smirnov, where all weak gauge boson masses can be substantially heavier than 100 GeV, is also described

  10. A model of interband radiative transition.

    Czech Academy of Sciences Publication Activity Database

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

    2004-01-01

    Ro?. 56, ?. 3 (2004), s. 753-786. ISSN 0025-5645 R&D Projects: GA AV ?R 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

  11. Analysis of spatial distribution of Cherenkov radiation of extensive air showers detected by a Samarkand state university device

    International Nuclear Information System (INIS)

    Investigations of spatial distribution functions (SDF) of the Cherenkov radiation of extensive air showers (EAS) are carried out. The results of the SDF calculation of the Cherenkov radiation are presented for two variants of the scaling model differing by the assumption on the character of growth of hadron inelastic interaction cross section with energy. Calculations are performed for purely proton composition of primary particles. In the first model the cross section increases according to the law: tau=tau0 (1+0.03 ln (E/100)), but in the second model it increases according to the law tau=tau0 (1+0.014 ln2 (E/100)) (E is energy in GeV). At small distances from the shower axis (100 m) the SDF is shown to be sensitive to the model calculation technique. It is anticipated from the data obtained that the variant of the second model gives higher location of maximum and is in better agreement with experimental data

  12. Dispersion modeling of air pollutants in the atmosphere: a review

    Science.gov (United States)

    Leel?ssy, Ádám; Molnár, Ferenc; Izsák, Ferenc; Havasi, Ágnes; Lagzi, István; Mészáros, Róbert

    2014-09-01

    Modeling of dispersion of air pollutants in the atmosphere is one of the most important and challenging scientific problems. There are several natural and anthropogenic events where passive or chemically active compounds are emitted into the atmosphere. The effect of these chemical species can have serious impacts on our environment and human health. Modeling the dispersion of air pollutants can predict this effect. Therefore, development of various model strategies is a key element for the governmental and scientific communities. We provide here a brief review on the mathematical modeling of the dispersion of air pollutants in the atmosphere. We discuss the advantages and drawbacks of several model tools and strategies, namely Gaussian, Lagrangian, Eulerian and CFD models. We especially focus on several recent advances in this multidisciplinary research field, like parallel computing using graphical processing units, or adaptive mesh refinement.

  13. Supersymmetric standard model and radiative meson decay

    International Nuclear Information System (INIS)

    I give a review on the generation-changing interactions of the supersymmetric standard model based on grand unification and N=1 supergravity. These interactions could make sizable effects on rare processes related to B-mesons. The decay b?s? is discussed in particular. It is shown that the inclusive branching ratio of the radiative B-meson decay is deviated from the standard model prediction in nontrivial ranges for parameter values. ((orig.))

  14. Radiative Effects in the Standard Model Extension

    OpenAIRE

    Zhukovsky, V. Ch; Lobanov, A. E.; Murchikova, E. M.

    2005-01-01

    The possibility of radiative effects induced by the Lorentz and CPT non-invariant interaction term for fermions in the Standard Model Extension is investigated. In particular, electron-positron photo-production and photon emission by electrons and positrons are studied. The rates of these processes are calculated in the Furry picture. It is demonstrated that the rates obtained in the framework of the model adopted strongly depend on the polarization states of the particles i...

  15. 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...

  16. 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)

  17. 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 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.

  18. 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)

  19. MODTRAN4: radiative transfer modeling for remote sensing

    Science.gov (United States)

    Anderson, Gail P.; Berk, Alexander; Acharya, Prabhat K.; Matthew, Michael W.; Bernstein, Lawrence S.; Chetwynd, James H., Jr.; Dothe, H.; Adler-Golden, Steven M.; Ratkowski, Anthony J.; Felde, Gerald W.; Gardner, James A.; Hoke, Michael L.; Richtsmeier, Steven C.; Pukall, Brian; Mello, Jason B.; Jeong, Laila S.

    1999-12-01

    MODTRAN4, the newly released version of the U.S. Air Force atmospheric transmission, radiance and flux model is being developed jointly by the Air Force Research Laboratory/Space Vehicles Directorate and Spectral Sciences, Inc. It is expected to provide the accuracy required for analyzing spectral data for both atmospheric and surface characterization. These two quantities are the subject of satellite and aircraft campaigns currently being developed and pursued by, for instance: NASA (Earth Observing System), NPOESS (National Polar Orbiting Environmental Satellite System), and the European Space Agency (GOME--Global Ozone Monitoring Experiment). Accuracy improvements in MODTRAN relate primarily to two major developments: (1) the multiple scattering algorithms have been made compatible with the spectroscopy by adopting a corrected-k approach to describe the statistically expected transmittance properties for each spectral bin and atmospheric layer, and (2) radiative transfer calculations can be conducted with a Beer-Lambert formulation that improves the treatment of path inhomogeneities. Other code enhancements include the incorporation of solar azimuth dependence in the DISORT- based multiple scattering model, the introduction of surface BRDF (Bi-directional Radiance Distribution Functions) models and 15 cm-1 band model for improved computational speed.

  20. Mathematical Modeling of Hot Air Drying of Spinach Leaves in Universal Hot Air Oven

    Directory of Open Access Journals (Sweden)

    A.K.Upadhyaya , Bhupendra Gupta , Sanjeev Garg , Mohan Singh , Mukesh Pandey

    2012-06-01

    Full Text Available The objective of this study was to develop a model for drying characteristic curve of Spinach in Universal Hot Air Oven .Drying experiment were conducted using a constant air velocity2.2m/s and three drying air temperature of 55, 65, and75 oC with two pretreatment conditions and load densities that are given respectively condition (Blanched and Unblanched load density (3kg/m2, 3.5 kg/m2.The drying rate increased with increased in temperature and decrease with increase in time. Pretreatment and load densities had an insignificant role on drying rate. The experimental drying data of spinach applied to four moisture ratio models, namely, page l, modified page, generalized exponential, and two term models. Nonlinear regression analysis performed to relate the parameters of the model with the drying conditions. The performance of these models evaluated by comparing the coefficient of determination, R2, and reduced chi-square, ?2, between the observed and predicted moisture ratio. Among all these model page model was found to be best describe the drying behavior of spinach leaves .the standard error of estimation was least(0.004-0.031 as well as coefficient of determination (R2was highest (0.991-1 in page model as compared to other models.

  1. Radiative torques: analytical model and basic properties

    Science.gov (United States)

    Lazarian, A.; Hoang, Thiem

    2007-07-01

    We attempt to get a physical insight into grain alignment processes by studying basic properties of radiative torques (RATs). For this purpose we consider a simple toy model of a helical grain that reproduces well the basic features of RATs. The model grain consists of a spheroidal body with a mirror attached at an angle to it. Being very simple, the model allows analytical description of RATs that act upon it. We show a good correspondence of RATs obtained for this model and those of irregular grains calculated by DDSCAT. Our analysis of the role of different torque components for grain alignment reveals that one of the three RAT components does not affect the alignment, but induces only for grain precession. The other two components provide a generic alignment with grain long axes perpendicular to the radiation direction, if the radiation dominates the grain precession, and perpendicular to magnetic field, otherwise. The latter coincides with the famous predictions of the Davis-Greenstein process, but our model does not invoke paramagnetic relaxation. In fact, we identify a narrow range of angles between the radiation beam and the magnetic field, for which the alignment is opposite to the Davis-Greenstein predictions. This range is likely to vanish, however, in the presence of thermal wobbling of grains. In addition, we find that a substantial part of grains subjected to RATs gets aligned with low angular momentum, which testifies that most of the grains in diffuse interstellar medium do not rotate fast, that is, rotate with thermal or even subthermal velocities. This tendency of RATs to decrease grain angular velocity as a result of the RAT alignment decreases the degree of polarization, by decreasing the degree of internal alignment, that is, the alignment of angular momentum with the grain axes. For the radiation-dominated environments, we find that the alignment can take place on the time-scale much shorter than the time of gaseous damping of grain rotation. This effect makes grains a more reliable tracer of magnetic fields. In addition, we study a self-similar scaling of RATs as a function of ?/aeff. We show that the self-similarity is useful for studying grain alignment by a broad spectrum of radiation, that is, interstellar radiation field.

  2. 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...

  3. A modeling perspective on cloud radiative forcing

    Energy Technology Data Exchange (ETDEWEB)

    Potter, G.L.; Corsetti, L. (Lawrence Livermore National Lab., CA (United States)); Slingo, J.M. (Univ. of Reading (United Kingdom)); Morcrette, J.J. (European Centre for Medium-Range Weather Forecasts, Reading (United Kingdom))

    1992-12-20

    Radiation fields from a perpetual July integration of a T106 version of the ECMWF 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 1 and 2 of Cess and Potter (1987) and a variant method are addressed. Method 1 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 2 is proposed as an unambiguous way to produce consistent radiative diagnostics for intercomparing model results. The impact of the three methods on the derived sensitivites 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. 20 refs., 2 figs., 1 tab.

  4. A modeling perspective on cloud radiative forcing

    Energy Technology Data Exchange (ETDEWEB)

    Potter, G.L.; Corsetti, L. [Lawrence Livermore National Lab., CA (United States); Slingo, J.M. [Reading Univ. (United Kingdom). Dept. of Meteorology; Morcrette, J.J. [European Centre for Medium-Range Weather Forecasts, Reading (United Kingdom)

    1993-02-01

    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.

  5. 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

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

    DEFF Research Database (Denmark)

    Delfs, Jens Olaf; Wang, Wenqing

    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 wave) shallow flow and two-phase flow in a porous medium. The simultaneous mass transfer between the soil, overland, and atmosphere compartments is achieved by upgrading a fully established leakance concept for overland-soil liquid exchange to an air exchange flux between soil and atmosphere. In a new algorithm, leakances operate as a valve for gas pressure in a liquid-covered porous medium facilitating the simulation of air out-break events through the land surface. General criteria are stated to guarantee stability in a sequential iterative coupling algorithm and, in addition, for leakances to control 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 runoff during high precipitation at specific sites, particularly in near-stream areas. © 2013 Springer-Verlag Berlin Heidelberg.

  7. Development of a model for radon concentration in indoor air

    International Nuclear Information System (INIS)

    A model is developed for calculation of the radon concentration in indoor air. The model takes into account various important parameters, e.g. radon concentration in ground, radon diffusion resistance of radon barrier, air permeance of ground, air pressure difference between outdoor ground and indoor at ground level, ventilation of the building ground and number of air changes per hour due to ventilation. Characteristic case studies are depicted in selected 2D and 3D graphical plots for easy visualization and interpretation. The radon transport into buildings might be dominated by diffusion, pressure driven flow or a mixture of both depending on the actual values of the various parameters. The results of our work indicate that with realistic or typical values of the parameters, most of the transport of radon from the building ground to the indoor air is due to air leakage driven by pressure differences through the construction. By incorporation of various and realistic values in the radon model, valuable information about the miscellaneous parameters influencing the indoor radon level is gained. Hence, the presented radon model may be utilized as a simple yet versatile and powerful tool for examining which preventive or remedial measures should be carried out to achieve an indoor radon level below the reference level as set by the authorities. - Highlights: ? Model development for calculation of radon concentration in indoor air. ? Radon model accounting for varioir. ? Radon model accounting for various important parameters. ? Characteristic case studies depicted in 2D and 3D graphical plots. ? May be utilized for examining radon preventive measures.

  8. 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)

  9. Modeling the ascent of sounding balloons: derivation of the vertical air motion

    Directory of Open Access Journals (Sweden)

    A. Gallice

    2011-10-01

    Full Text Available A new model to describe the ascent of sounding balloons in the troposphere and lower stratosphere (up to ?30–35 km altitude is presented. Contrary to previous models, detailed account is taken of both the variation of the drag coefficient with altitude and the heat imbalance between the balloon and the atmosphere. To compensate for the lack of data on the drag coefficient of sounding balloons, a reference curve for the relationship between drag coefficient and Reynolds number is derived from a dataset of flights launched during the Lindenberg Upper Air Methods Intercomparisons (LUAMI campaign. The transfer of heat from the surrounding air into the balloon is accounted for by solving the radial heat diffusion equation inside the balloon. In its present state, the model does not account for solar radiation, i.e. it is only able to describe the ascent of balloons during the night. It could however be adapted to also represent daytime soundings, with solar radiation modeled as a diffusive process. The potential applications of the model include the forecast of the trajectory of sounding balloons, which can be used to increase the accuracy of the match technique, and the derivation of the air vertical velocity. The latter is obtained by subtracting the ascent rate of the balloon in still air calculated by the model from the actual ascent rate. This technique is shown to provide an approximation for the vertical air motion with an uncertainty error of 0.5 m s?1 in the troposphere and 0.2 m s?1 in the stratosphere. An example of extraction of the air vertical velocity is provided in this paper. We show that the air vertical velocities derived from the balloon soundings in this paper are in general agreement with small-scale atmospheric velocity fluctuations related to gravity waves, mechanical turbulence, or other small-scale air motions measured during the SUCCESS campaign (Subsonic Aircraft: Contrail and Cloud Effects Special Study in the orographically unperturbed mid-latitude middle troposphere.

  10. 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

  11. Artificial neural network estimation of global solar radiation using air temperature and relative humidity

    International Nuclear Information System (INIS)

    Measured air temperature and relative humidity values between 1998 and 2002 for Abha city in Saudi Arabia were used for the estimation of global solar radiation (GSR) in future time domain using artificial neural network method. The estimations of GSR were made using three combinations of data sets namely: (i) day of the year and daily maximum air temperature as inputs and GSR as output, (ii) day of the year and daily mean air temperature as inputs and GSR as output and (iii) time day of the year, daily mean air temperature and relative humidity as inputs and GSR as output. The measured data between 1998 and 2001 were used for training the neural networks while the remaining 240 days' data from 2002 as testing data. The testing data were not used in training the neural networks. Obtained results show that neural networks are well capable of estimating GSR from temperature and relative humidity. This can be used for estimating GSR for locations where only temperature and humidity data are available

  12. Modelling of air pollution dispersion in Santiago de Chile

    Science.gov (United States)

    Schmitz, Rainer

    In Santiago de Chile air quality standards are frequently exceeded during both summer and winter time. The evaluation of the temporal and spatial evolution of the chemical and physical characteristics of these air pollution problems requires the application of three-dimensional models. In this work, the Chilean Air Pollution Dispersion Model (CADM), a three-dimensional Eulerian chemical transport model is presented. The model is applied for the simulation of air pollution dispersion during summer. Carbon monoxide (CO) dispersion is studied in order to evaluate advection and diffusion as simulated by CADM and to characterise dispersion patterns in the Santiago basin. Horizontal and vertical dispersion patterns are presented, explaining how pollutants are ventilated out of the Santiago basin. Also, the role of turbulence on the pollutant distribution is discussed. Furthermore, an attempt is made to explain how pollutants are accumulated in the basin during night in the nocturnal stable planetary boundary layer and what mechanisms affect the transport of pollutants under these conditions. Comparing results from model simulations with observations, it can be shown that the model is able to represent the diurnal cycles of CO reasonably well. It can be concluded that CADM is suited for the application of air pollution dispersion in the Santiago basin in particular and complex terrain in general.

  13. 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)

  14. Formation of an optical pulsed discharge in a supersonic air flow by radiation of a repetitively pulsed CO2 laser

    International Nuclear Information System (INIS)

    Results of optimisation of repetitively pulsed CO2-laser generation are presented for finding physical conditions of forming stable burning of an optical pulsed discharge (OPD) in a supersonic air flow and for studying the influence of pulse parameters on the energy absorption efficiency of laser radiation in plasma. The optical discharge in a supersonic air flow was formed by radiation of a repetitively pulsed CO2 laser with mechanical Q-switching excited by a discharge with a convective cooling of the working gas. For the first time the influence of radiation pulse parameters on the ignition conditions and stable burning of the OPD in a supersonic air flow was investigated and the efficiency of laser radiation absorption in plasma was studied. The influence of the air flow velocity on stability of plasma production was investigated. It was shown that stable burning of the OPD in a supersonic flow is realised at a high pulse repetition rate where the interval between radiation pulses is shorter than the time of plasma blowing-off. Study of the instantaneous value of the absorption coefficient shows that after a breakdown in a time lapse of 100 — 150 ns, a quasi-stationary 'absorption phase' is formed with the duration of ?1.5 ms, which exists independently of air flow and radiation pulse repetition rate. This phase of strong absorption is, seemingly, related to evolution of the ionisation wave. (laser applications and other topics in quantumplications and other topics in quantum electronics)

  15. Radiative torques: Analytical Model and Basic Properties

    CERN Document Server

    Lazarian, Alex

    2007-01-01

    We attempt to get a physical insight into grain alignment processes by studying basic properties of radiative torques (RATs). For this purpose we consider a simple toy model of a helical grain that reproduces well the basic features of RATs. The model grain consists of a spheroidal body with a mirror attached at an angle to it. Being very simple, the model allows analytical description of RATs that act upon it. We show a good correspondence of RATs obtained for this model and those of irregular grains calculated by DDSCAT. Our analysis of the role of different torque components for grain alignment reveals that one of the three RAT components does not affect the alignment, but induces only for grain precession. The other two components provide a generic alignment with grain long axes perpendicular to the radiation direction, if the radiation dominates the grain precession, and perpendicular to magnetic field, otherwise. We study a self-similar scaling of RATs as a function of $\\lambda/a_{eff}$. We show that th...

  16. Health physics experience with nondestructive X-radiation facilities in the US Air Force

    International Nuclear Information System (INIS)

    Radiation safety experience in the construction and use of enclosed nondestructive inspection (NDI) facilities in the US Air Force, has reaffirmed the constant need for the health physicist to continually monitor and assit in upgrading these facilities. Health physics contributions include evaluation of initial shielding requirements, proper selection of construction material, insuring that adequate safety devices are installed and adequate personnel dosimetry devices are available, surveying the facility, and assisting in the safety education program. There is a need to better define NDI warning/safety devices, using the National Bureau of Standards, (NBS) Handbook 107 as the most applicable guide

  17. Quantifying air-conducted acoustic radiation from the bone-conduction vibrator.

    Science.gov (United States)

    Harkrider, A W; Martin, F N

    1998-12-01

    Sound pressure levels in the external auditory canals of 50 subjects were measured at 2000 and 4000 Hz with a bone-conduction vibrator on the forehead, the mastoid ipsilateral to the probe microphone, and the mastoid contralateral to the probe microphone. A plug was placed in the external auditory canal to minimize sound pressure levels in the external auditory canal produced by the osseotympanic mode of bone conduction. Results suggest that clinically significant false air-bone gaps (greater than 10 dB) due to acoustic radiation into the concha from the bone-conduction vibrator are most likely to occur at 4000 Hz when the bone-conduction vibrator is placed on the mastoid of the test ear. To minimize the possible confounding effects of acoustic radiation, the bone-conduction vibrator may be placed on the forehead or the mastoid contralateral to the test ear while masking the nontest ear. PMID:9865773

  18. 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

  19. Gaschromatographic proof of nitrous oxide concentrations in air by means of radiation ionization detectors

    International Nuclear Information System (INIS)

    For the analysis of nitrous oxide concentrations at workplaces in operating theatres, gaschromatography is a particularly suitable method if it is possible to measure nitrous oxide concentrations in the ppm to ppb region. For this, most frequently used gaschromatographic detectors (flame ionization detector, thermal conductivity detector) are unsuitable, whereas radiation ionization detectors can be used successfully. The investigations using detectors designed at the Central Institute for Isotopes and Radiation Research of the GDR Academy of Sciences showed that a high-temperature electron-capture detector (ECD), working at a temperatur of 250 0C, enables the determination of traces of nitrous oxide with a detection limit of about 200 ppb, while the helium detector has a limit of 50 ppb of nitrous oxide in room air. Since the helium detector requires extremely pure carrier gas, the high-temperature ECD appears more suitable for analyzing nitrous oxide. (author)

  20. 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)

  1. 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)

  2. Modeling air temperature changes in Northern Asia

    Science.gov (United States)

    Onuchin, A.; Korets, M.; Shvidenko, A.; Burenina, T.; Musokhranova, A.

    2014-11-01

    Based on time series (1950-2005) of monthly temperatures from 73 weather stations in Northern Asia (limited by 70-180° EL and 48-75° NL), it is shown that there are statistically significant spatial differences in character and intensity of the monthly and yearly temperature trends. These differences are defined by geomorphological and geographical parameters of the area including exposure of the territory to Arctic and Pacific air mass, geographic coordinates, elevation, and distances to Arctic and Pacific oceans. Study area has been divided into six domains with unique groupings of the temperature trends based on cluster analysis. An original methodology for mapping of temperature trends has been developed and applied to the region. The assessment of spatial patterns of temperature trends at the regional level requires consideration of specific regional features in the complex of factors operating in the atmosphere-hydrosphere-lithosphere-biosphere system.

  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. Air flow modeling in deep wells : application to mining ventilation

    OpenAIRE

    Witrant, E.; 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 mode...

  5. Fluctuations of spatial distribution function of Cherenkov radiation of extensive air showers in the 1015-1016 eV range

    International Nuclear Information System (INIS)

    Fluctuation of spatial distribution function (SDF) of Cherenkov radiation of extensive air showers (EAS) in the 1015-1016 eV energy range is investigated. Data obtained at the Samarkand plant, are used. Experiment matematical modelling is conducted. EAS with ??30 deg zenith angles and energy E0>2.5x1015 eV, registered at the plant in 1983, were used for the analysis. It is shown, that SDF parameter of Cherenkov radiation depends on the distance up to the individual EAS maximum

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

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Won Taek; Kwon, Byung Hyun; Kang, Dong Mug; Ki, Yong Kan; Kim, Dong Won [Pusan National University, Busan (Korea, Republic of); Shin, Yong Chul [Inje University, Busan (Korea, Republic of)

    2005-12-15

    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.

  7. 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 e 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

  8. Modeling of sound radiation by a beam

    Directory of Open Access Journals (Sweden)

    ?.?. Zaporozhets

    2005-03-01

    Full Text Available  An analytical formulation and numerical analysis are presented for the vibration and following noise radiation of a simply supported beam. The analytical solution was found in a form that is appropriate to describe the control of the beam vibration using active structures. The modeling approach can be used for forming of feedback control of the system of vibration loads by means of distribution of the actuators along the beam length.

  9. Atmospheric transmittance model for photosynthetically active radiation

    Energy Technology Data Exchange (ETDEWEB)

    Paulescu, Marius; Stefu, Nicoleta; Gravila, Paul; Paulescu, Eugenia; Boata, Remus; Pacurar, Angel; Mares, Oana [Physics Department, West University of Timisoara, V Parvan 4, 300223 Timisoara (Romania); Pop, Nicolina [Department of Physical Foundations of Engineering, Politehnica University of Timisoara, V Parvan 2, 300223 Timisoara (Romania); Calinoiu, Delia [Mechanical Engineering Faculty, Politehnica University of Timisoara, Mihai Viteazu 1, 300222 Timisoara (Romania)

    2013-11-13

    A parametric model of the atmospheric transmittance in the PAR band is presented. The model can be straightforwardly applied for calculating the beam, diffuse and global components of the PAR solar irradiance. The required inputs are: air pressure, ozone, water vapor and nitrogen dioxide column content, Ångström's turbidity coefficient and single scattering albedo. Comparison with other models and ground measured data shows a reasonable level of accuracy for this model, making it suitable for practical applications. From the computational point of view the calculus is condensed into simple algebra which is a noticeable advantage. For users interested in speed-intensive computation of the effective PAR solar irradiance, a PC program based on the parametric equations along with a user guide are available online at http://solar.physics.uvt.ro/srms.

  10. 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. ciurban forest managers in U.S. cities a framework to quantify and visualize urban forest structure and its air pollution removal effect.

  11. Modelling the risk of airborne infectious disease using exhaled air.

    Science.gov (United States)

    Issarow, Chacha M; Mulder, Nicola; Wood, Robin

    2015-05-01

    In this paper we develop and demonstrate a flexible mathematical model that predicts the risk of airborne infectious diseases, such as tuberculosis under steady state and non-steady state conditions by monitoring exhaled air by infectors in a confined space. In the development of this model, we used the rebreathed air accumulation rate concept to directly determine the average volume fraction of exhaled air in a given space. From a biological point of view, exhaled air by infectors contains airborne infectious particles that cause airborne infectious diseases such as tuberculosis in confined spaces. Since not all infectious particles can reach the target infection site, we took into account that the infectious particles that commence the infection are determined by respiratory deposition fraction, which is the probability of each infectious particle reaching the target infection site of the respiratory tracts and causing infection. Furthermore, we compute the quantity of carbon dioxide as a marker of exhaled air, which can be inhaled in the room with high likelihood of causing airborne infectious disease given the presence of infectors. We demonstrated mathematically and schematically the correlation between TB transmission probability and airborne infectious particle generation rate, ventilation rate, average volume fraction of exhaled air, TB prevalence and duration of exposure to infectors in a confined space. PMID:25702940

  12. 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.

  13. Mathematical model of an air-filled alpha stirling refrigerator

    Science.gov (United States)

    McFarlane, Patrick; Semperlotti, Fabio; Sen, Mihir

    2013-10-01

    This work develops a mathematical model for an alpha Stirling refrigerator with air as the working fluid and will be useful in optimizing the mechanical design of these machines. Two pistons cyclically compress and expand air while moving sinusoidally in separate chambers connected by a regenerator, thus creating a temperature difference across the system. A complete non-linear mathematical model of the machine, including air thermodynamics, and heat transfer from the walls, as well as heat transfer and fluid resistance in the regenerator, is developed. Non-dimensional groups are derived, and the mathematical model is numerically solved. The heat transfer and work are found for both chambers, and the coefficient of performance of each chamber is calculated. Important design parameters are varied and their effect on refrigerator performance determined. This sensitivity analysis, which shows what the significant parameters are, is a useful tool for the design of practical Stirling refrigeration systems.

  14. Mathematical modeling of compression processes in air-driven boosters

    International Nuclear Information System (INIS)

    The compressed air in normal pressure is used as the source of power of the air-driven booster. The continuous working of air-driven boosters relies on the difference of surface area between driven piston and driving piston, i.e., the different forces acting on the pistons. When the working surface area of the driving piston for providing power is greater than that of the driven piston for compressing gas, the gas in compression chamber will be compressed. On the basis of the first law of thermodynamics, the motion regulation of piston is analyzed and the mathematical model of compression processes is set up. Giving a calculating example, the vary trends of gas pressure and pistons' move in working process of booster have been gotten. The change of parameters at different working conditions is also calculated and compared. And the corresponding results can be referred in the design of air-driven boosters

  15. 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.

  16. Modelling and optimization of air electrode

    Energy Technology Data Exchange (ETDEWEB)

    Viitanen, M. (Helsinki University of Technology, Espoo (FI))

    1990-11-01

    The model takes into account the transport processes of reactant, electrochemical reactions taking place, ohmic drop in the electrolyte and also ohmic drop in the material. In the model the agglomerates are assumed to have a shape of cylinders. The model electrode consist of equal elements, which are arraged in a two dimensional array, Each element is composed of the cylinder, hydrophobic zone which surrounds the cylinders and of a part of the gas supplying layer which thickness is d{sub 0}. The model electrode is presented. During the operation the reactant is diffuses through the gas supplying layer to hydrophobic zone in the reaction layer, dissolves to the electrolyte contained in the cylinder and after diffusing a certain distance reacts on an active site of a catalyst particle. The generated ionic current is conducted towards the free electrolyte. The structure of electrode may be optimized with this model. (AB).

  17. A new one-dimensional radiative equilibrium model for investigating atmospheric radiation entropy flux

    OpenAIRE

    Wu, Wei; Liu, Yangang

    2010-01-01

    A new one-dimensional radiative equilibrium model is built to analytically evaluate the vertical profile of the Earth's atmospheric radiation entropy flux under the assumption that atmospheric longwave radiation emission behaves as a greybody and shortwave radiation as a diluted blackbody. Results show that both the atmospheric shortwave and net longwave radiation entropy fluxes increase with altitude, and the latter is about one order in magnitude greater than the former. The vertical profil...

  18. Dimuon radiation from a hybrid evolution model

    International Nuclear Information System (INIS)

    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.

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

    Science.gov (United States)

    Cole, J.; Su, S.; Blakeley, R. E.; Koonath, P.; Hecht, A. A.

    2015-01-01

    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.

  20. 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.

  1. Evaluation of global solar radiation models for Shanghai, China

    International Nuclear Information System (INIS)

    Highlights: • 108 existing models are compared and analyzed by 42 years meteorological data. • Fitting models based on measured data are established according to 42 years data. • All models are compared by recently 10 years meteorological data. • The results show that polynomial models are the most accurate models. - Abstract: In this paper, 89 existing monthly average daily global solar radiation models and 19 existing daily global solar radiation models are compared and analyzed by 42 years meteorological data. The results show that for existing monthly average daily global solar radiation models, linear models and polynomial models have been able to estimate global solar radiation accurately, and complex equation types cannot obviously improve the precision. Considering direct parameters such as latitude, altitude, solar altitude and sunshine duration can help improve the accuracy of the models, but indirect parameters cannot. For existing daily global solar radiation models, multi-parameter models are more accurate than single-parameter models, polynomial models are more accurate than linear models. Then measured data fitting monthly average daily global solar radiation models (MADGSR models) and daily global solar radiation models (DGSR models) are established according to 42 years meteorological data. Finally, existing models and fitting models based on measured data are comparative analysis by recent 10 years meteorological data, and the results show that polynomial models (MADGSR model 2, DGSR model 2 and Maduekwe model 2) are the most accurate models

  2. Mathematical Modelling of Air Streams in Large Spaces

    Directory of Open Access Journals (Sweden)

    V.N.Mel'kumov

    2015-02-01

    Full Text Available Statement of the problem. The greatest contribution to solution the problem of mathematical modeling of air streams in large spaces was made using the methods which are based on the sys-tem of the equations of a hydraulic gas dynamics. These methods involve a great deal of computer calculations, and errors can affect the accuracy of the resulting lines of current, and its qualitative character on the whole. In this article the analytical way of the calculation of geometrical and nu-merical characteristics of air streams of large premises based on the conformal mapping method is considered.Results.The mathematical model of air streams of displacement ventilation of spectator galleries based on the theory of conformal mapping is developed. The model is based on the use of symme-try of rectangular rooms and elliptic integral. The developed mathematical model can be applied to a mode of a currentof the environment with a minimum vortex formation.Conclusions.The implementation of a function of elliptic integral in packages of symbolical ma-thematics maintains a high level of accuracy of numerical studies of the suggested model that al-lows an increase in the reliability of the obtained results. The important characteristics of model is possibly accurate analytical solution of the problem of designing air velocity rates in spectator tribunes.

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

    Directory of Open Access Journals (Sweden)

    Tiziano Tirabassi

    2013-07-01

    Full Text Available 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 solution of the advection-diffusion equation considering a vertically inhomogeneous atmospheric boundary layer for arbitrary vertical profiles of wind and eddy-diffusion coefficients. Numerical results and comparison with experimental data are shown.

  4. ANL/HIWAY: an air pollution evaluation model for roadways

    Energy Technology Data Exchange (ETDEWEB)

    Concaildi, G. A.; Cohen, A. S.; King, R. F.

    1976-12-01

    This report describes a computer program, called ANL/HIWAY, for estimating air quality levels of nonreactive pollutants produced by vehicular sources. It is valid for receptors at distances of tens to hundreds of meters, at an angle, downwind of the roadway, in relatively uncomplicated terrain. It may be used by planners to analyze the effects of a proposed roadway on adjacent air quality. The ANL/HIWAY model expands the evaluation capabilities of the EPA/HIWAY dispersion model. This report also serves as a user's manual for running the ANL/HIWAY PROGRAM. All command structures are described in detail, with sample problems exemplifying their use.

  5. Development and Evaluation of Global Solar Radiation Models Based on Sunshine Hours and Meteorological Data

    Directory of Open Access Journals (Sweden)

    A Majnoni-Heris

    2009-01-01

    Full Text Available Global solar radiation (Rs has wide applications in several disciplines. The data of measured or predicted Rs are widely applied by solar engineers, architects, agriculturists and hydrologists. Due to the importance of Rs, several empirical models have been developed to predict its values all over the world. In this study, Angstrom model was calibrated based on the ratio of actual and possible sunshine hours n/N by using measured daily data of Rs at Bajghah meteorological station in Fars province during 2003-2004. The model was modified by using air temperature for considering the effect of cloudy conditions as well as n/N ratios. The results showed that using both the air temperatures and the ratios of n/N led to a higher accuracy. In regard to estimation of the Rs values, the results showed that mean air temperatures have a higher accuracy compared with differences between maximum and minimum air temperatures. Also, a new local model with higher accuracy was developed based on a number of daily meteorological parameters such as deficit vapor pressure, relative humidity, precipitation, mean air temperature, maximum and minimum air temperatures difference and n/N. This new local model that used different meteorological parameters had the highest accuracy in comparison with the other models. Also, a number of models developed by other investigators for estimation of Rs were calibrated for the study area. Finally, different selected models were validated by using the measured data of Rs in 2005. The results showed that the developed local multi-variable model provided higher accuracy results in comparison with the other radiation models.

  6. 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.

  7. International Space Station Radiation Shielding Model Development

    Science.gov (United States)

    Qualls, G. D.; Wilson, J. W.; Sandridge, C.; Cucinotta, F. A.; Nealy, J. E.; Heinbockel, J. H.; Hugger, C. P.; Verhage, J.; Anderson, B. M.; Atwell, W.

    2001-01-01

    The projected radiation levels within the International Space Station (ISS) have been criticized by the Aerospace Safety Advisory Panel in their report to the NASA Administrator. Methods for optimal reconfiguration and augmentation of the ISS shielding are now being developed. The initial steps are to develop reconfigurable and realistic radiation shield models of the ISS modules, develop computational procedures for the highly anisotropic radiation environment, and implement parametric and organizational optimization procedures. The targets of the redesign process are the crew quarters where the astronauts sleep and determining the effects of ISS shadow shielding of an astronaut in a spacesuit. The ISS model as developed will be reconfigurable to follow the ISS. Swapping internal equipment rack assemblies via location mapping tables will be one option for shield optimization. Lightweight shield augmentation materials will be optimally fit to crew quarter areas using parametric optimization procedures to minimize the augmentation shield mass. The optimization process is being integrated into the Intelligence Synthesis Environment s (ISE s) immersive simulation facility at the Langley Research Center and will rely on High Performance Computing and Communication (HPCC) for rapid evaluation of shield parameter gradients.

  8. 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)

  9. Inflation in a modified radiative seesaw model

    Science.gov (United States)

    Budhi, Romy H. S.; Kashiwase, Shoichi; Suematsu, Daijiro

    2014-12-01

    The existence of the inflationary era in the early Universe seems to be strongly supported by recent CMB observations. However, only a few realistic inflation scenarios which have close relation to particle physics seem to have been known unfortunately. The radiative neutrino mass model with inert doublet dark matter is a promising model for the present experimental issues which cannot be explained within the standard model. In order to make the model include inflation, we extend it by a complex scalar field with a specific potential. This scalar could be closely related to the neutrino mass generation at a TeV scale as well as inflation. We show that the inflation favored by the CMB observations could be realized even if inflaton takes sub-Planck values during inflation.

  10. Inflation in a modified radiative seesaw model

    CERN Document Server

    Budhi, Romy H S; Suematsu, Daijiro

    2014-01-01

    The existence of the inflationary era in the early Universe seems to be strongly supported by recent CMB observations. However, only a few realistic inflation scenarios which have close relation to particle physics seem to have been known unfortunately. The radiative neutrino mass model with inert doublet dark matter is a promising model for the present experimental issues which cannot be explained within the standard model. In order to make the model include inflation, we extend it by a complex scalar field with a specific potential. This scalar could be closely related to the neutrino mass generation at a TeV scale as well as inflation. We show that the inflation favored by the CMB observations could be realized even if inflaton takes sub-Planck values during inflation.

  11. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Chang H., E-mail: Chang.Oh@inl.go [Idaho National Laboratory, Idaho Falls, ID 83415-3870 (United States); Kang, Hyung S.; Kim, Eung S. [Idaho National Laboratory, Idaho Falls, ID 83415-3870 (United States)

    2011-01-15

    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.

  13. Radiative equilibrium model of Titan's atmosphere

    Science.gov (United States)

    Samuelson, R. E.

    1983-01-01

    The present global radiative equilibrium model for the Saturn satellite Titan is restricted to the two-stream approximation, is vertically homogeneous in its scattering properties, and is spectrally divided into one thermal and two solar channels. Between 13 and 33% of the total incident solar radiation is absorbed at the planetary surface, and the 30-60 ratio of violet to thermal IR absorption cross sections in the stratosphere leads to the large temperature inversion observed there. The spectrally integrated mass absorption coefficient at thermal wavelengths is approximately constant throughout the stratosphere, and approximately linear with pressure in the troposphere, implying the presence of a uniformly mixed aerosol in the stratosphere. There also appear to be two regions of enhanced opacity near 30 and 500 mbar.

  14. ESTUDIO NUMÉRICO Y EXPERIMENTAL DE LAS PROPIEDADES Y FENÓMENOS RADIATIVOS EN UNA LLAMA DE METANO (CH4) CON AIRE ENRIQUECIDO / NUMERICAL AND EXPERIMENTAL STUDY OF THE RADIATIVE PROPERTIES AND PHENOMENA IN A METHANE (CH4) FLAME WITH ENRICHED AIR

    Scientific Electronic Library Online (English)

    JOSE LUIS, SUÁREZ; ANDRÉS AMELL, ARRIETA; FRANCISCO JAVIER, CADAVID.

    2011-02-01

    Full Text Available En este artículo, se presenta un estudio numérico y experimental del comportamiento de la radiación de una llama de metano con aire enriquecido con bajas concentraciones oxígeno. Se midió el flux de calor por radiación y se determinó su relación con el porcentaje de enriquecimiento del aire, permiti [...] endo estimar las propiedades radiantes de la llama en función del enriquecimiento con oxígeno. Se utilizó aire con concentraciones de oxígeno desde 21% hasta 22,5%. La simulación se realizó con el software Fluent V6.2.16 y para resolver la ecuación de transferencia radiativa se empleó el modelo de las Ordenadas Discretas. Las propiedades radiantes de la mezcla de gases de combustión (CO, CO2 y H2O) se cuantificaron empleando el modelo de la Suma Ponderada de Gases Grises (WSGGM). La experimentación se llevó a cabo empleando como combustible Gas Natural de la Guajira, un factor de aireación de 1,1 y una potencia térmica de 1,54 kW. Se utilizó un quemador de premezcla tipo Bunsen, en el que se inducía el aire, el cual a su vez es enriquecido con oxígeno proveniente de un cilindro. Abstract in english This article proposes a numerical and experimental study of the radiation behavior in a methane flame with air enhanced with oxygen at low concentrations. It was measured the heat flux by radiation and was determined its relationship with the percentage of enrichment of the air, which allowed to est [...] imate the radiant properties of the flame in terms of oxygen enrichment. Was used air with oxygen concentrations from 21% to 22,5%. The simulation was done with the software Fluent V6.2.16 and to solve the radiative transfer equation was used the Discrete Ordinates model. The radiant properties of the mixture of combustion gases (CO, CO2 and H2O) were quantified using the Weighted Sum of Gray Gases Model (WSGGM). The experiment was carried out using Guajira Natural Gas as fuel, an air factor equal to 1,1 and a thermal power of 1,54 kW.

  15. 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.

  16. Likelihood of achieving air quality targets under model uncertainties.

    Science.gov (United States)

    Digar, Antara; Cohan, Daniel S; Cox, Dennis D; Kim, Byeong-Uk; Boylan, James W

    2011-01-01

    Regulatory attainment demonstrations in the United States typically apply a bright-line test to predict whether a control strategy is sufficient to attain an air quality standard. Photochemical models are the best tools available to project future pollutant levels and are a critical part of regulatory attainment demonstrations. However, because photochemical models are uncertain and future meteorology is unknowable, future pollutant levels cannot be predicted perfectly and attainment cannot be guaranteed. This paper introduces a computationally efficient methodology for estimating the likelihood that an emission control strategy will achieve an air quality objective in light of uncertainties in photochemical model input parameters (e.g., uncertain emission and reaction rates, deposition velocities, and boundary conditions). The method incorporates Monte Carlo simulations of a reduced form model representing pollutant-precursor response under parametric uncertainty to probabilistically predict the improvement in air quality due to emission control. The method is applied to recent 8-h ozone attainment modeling for Atlanta, Georgia, to assess the likelihood that additional controls would achieve fixed (well-defined) or flexible (due to meteorological variability and uncertain emission trends) targets of air pollution reduction. The results show that in certain instances ranking of the predicted effectiveness of control strategies may differ between probabilistic and deterministic analyses. PMID:21138291

  17. Second law optimization of flat-plate solar air heaters. Part I. The concept of net exergy flow and the modeling of solar air heaters

    Energy Technology Data Exchange (ETDEWEB)

    Altfeld, K.; Leiner, W.; Fiebig, M.

    1988-01-01

    In solar air heating systems, the compression energy needed to overcome friction losses can reduce essentially the benefit from solar heat. Thus the design of solar air heaters with high heat transfer rates and low friction losses is of particular interest. The net exergy flow as defined is a suitable quantity for balancing useful energy and friction losses. By maximizing the net exergy flow the sum of exergy losses, including exergy losses by absorption of radiation at the absorber temperature level, is minimized and reasonably optimized designs of absorbers and flow ducts are found. Different types of solar air heaters have been modeled with regard to thermal performance characteristics and to pressure drop for the calculation of net exergy flow.

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

    Science.gov (United States)

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

    2015-01-01

    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-Väisälä 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.

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

    DEFF Research Database (Denmark)

    Kaiser, Franz-Joachim; Bassler, Niels

    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" recombination) is the Jaffe theory, which was developed in 1913 by Jaffe. He solved a differential equation by applying several simplifications and approximations such as a Gaussian shaped track whose width serves as free parameter. These simplifications and the use of an simplified charge carrier distribution are leading to discrepancies between theory and experiments. Material and Methods We solved the fundamental differential equation presented by Jaffe numerically, taking into account both diffusion and recombination terms and realistic models of the initial charge carrier distribution developed by track structure theory. More specifically, we solved the equation for the geometrical setup of the Bragg-peak IC, which is a plane parallel IC with a 2 mm spacing between the electrodes. The sensitive volume of the IC is located in a thermoplastic housing of several mm thickness. Results We compare the experimental results of the collection efficiency of the Bragg peak IC to both the Jaffe theory and to our numerical solution of the diffusion recombination equation. Fitting a Jaffe curve to the measured collection efficiency resulted in values comparable to the literature. Calculations assuming radial dose distributions coming from track structure require long computation times, caused by the high spatial resolution and the subsequent requirements to temporal resolution. Conclusion Our numerical solution of the diffusion recombination assuming a Gaussian beam shape is relatively well described by the Jaffe theory. Additionally, preliminary results show that that the calculated response does not depend on the core radius of the radial dose distribution. References JAFFE, G.C:  On the theory of columnar recombination.  Annalen der Physik.  42, 303-344, 1913. KANAI, T. et al.: Initial recombination in a parallel-plate ionization chamber exposed to heavy ions Phys. Med. Biol. 43 3549–58, 1998. ELSAESSER, T. et al.: Impact of track structure on biological treatment planning ion ion radiotherapy. New Journal pf Physics 10. 075005, 2008

  20. 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.

  1. Measurement and Modeling of Particle Radiation in Coal Flames

    DEFF Research Database (Denmark)

    Ba?ckstro?m, Daniel; Johansson, Robert

    2014-01-01

    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 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 about particle radiation and temperature, the methodology can also provide estimates of the amount of soot radiation and the maximum contribution from soot radiation compared to the total particle radiation. In the center position in the flame, the maximum contribution from soot radiation was estimated to be less than 40% of the particle radiation. As a validation of the methodology, the modeled total radiative intensity was compared to the total intensity measured with a narrow angle radiometer and the agreement in the results was good, supporting the validity of the used approach.

  2. Mathematical modeling of heat transfer between the plant seedling and the environment during a radiation frost

    Directory of Open Access Journals (Sweden)

    Finnikov K.A.

    2010-11-01

    Full Text Available The power of the internal heat source sufficient to maintain a positive temperature of plants during one of the possible form of cold stress - radiation frost was determined with the help of numerical simulation.The simulation of unsteady heat transfer in the soil-plant-air system in the conditions of radiation frost showed that the the ground part of plants is cooling most rapidly, and this process is partially slowed down by the natural-convection heat transfer with warmer air. If the frost is not continuous, the radiative cooling is the main danger for plant. The necessary power of heat-production inside plant that allows it to avoid hypothermia depends both on natural conditions and the size of the plant. For plants with a typical diameter of the stem about 2 mm this heat-production should be from 50 to 100 W / kg. Within 2 hours a total amount of heat about 0.5 MJ / kg in the plant should be allocated. Larger plants will have a smaller surface to mass ratio, and the maintaining of it's temperature will require a lower cost of nutrients per unit, accordingly. Modeling of the influence of plant surface trichomes presence on the process of its cooling showed that the role of trichomes in the protection of plants from hypothermia during radiation frost usually is negative due to the fact that the presence of trichomes increases the radiative heat transfer from the plant and the impediment in air movement near the plant reduces heat flux entering the plant from a warmer air. But in cases where the intensity of heat generation within the plant is sufficient for the maintenance of the plant temperature higher than the air temperature, the presence of trichomes impairs heat transfer from plant to air, and therefore contributes to a better heating of plants.

  3. CFD model of air movement in ventilated façade: comparison between natural and forced air flow

    OpenAIRE

    Miguel Mora Pérez, Gonzalo López Patiño, P. Amparo López Jiménez

    2013-01-01

    This study describes computational fluid dynamics (CFD) modeling of ventilated façade. Ventilated façades are normal façade but it has an extra channel between the concrete wall and the (double skin) façade. Several studies found in the literature are carried out with CFD simulations about the behavior of the thermodynamic phenomena of the double skin façades systems. These studies conclude that the presence of the air gap in the ventilated façade affects the temperature in the building...

  4. 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)

  5. Discontinuous Galerkin Method for the Air Pollution Model

    Directory of Open Access Journals (Sweden)

    Xijian Wang

    2013-06-01

    Full Text Available In this paper we present the discontinuous Galerkin method to solve the problem of the two-dimensional air pollution model. The resulting system of ordinary differential equations is called the semidiscrete formulation. We show the existence and uniqueness of the ODE system and provide the error estimates for the numerical error.

  6. Discontinuous Galerkin Method for the Air Pollution Model

    CERN Document Server

    Zhao, Lite; Hou, Qinzhi

    2011-01-01

    In this paper we present the discontinuous Galerkin method to solve the problem of the two-dimensional air pollution model. The resulting system of ordinary differential equations is called the semidiscrete formulation. We show the existence and uniqueness of the ODE system and provide the error estimates for the numerical error.

  7. Pollutant dispersion models for issues of air pollution control

    International Nuclear Information System (INIS)

    14 papers entered separately into the data base were presented at the meeting for application-oriented dispersion models for issues of air pollution control. These papers focus on fields of application, availability of required input data relevant to emissions and meteorology, performance and accuracy of these methods and their practicability. (orig./PW)

  8. ANALYTICAL DIFFUSION MODEL FOR LONG DISTANCE TRANSPORT OF AIR POLLUTANTS

    Science.gov (United States)

    A steady-state two-dimensional diffusion model suitable for predicting ambient air pollutant concentrations averaged over a long time period (e.g., month, season, or year) and resulting from the transport of pollutants for distances greater than about 100 km from the source is de...

  9. Discontinuous Galerkin Method for the Air Pollution Model

    OpenAIRE

    Xijian Wang; Lite Zhao

    2013-01-01

    In this paper we present the discontinuous Galerkin method to solve the problem of the two-dimensional air pollution model. The resulting system of ordinary differential equations is called the semidiscrete formulation. We show the existence and uniqueness of the ODE system and provide the error estimates for the numerical error.

  10. 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 ex...

  11. 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.

  12. 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

  13. 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)

  14. The role of clouds in improving the regression model for hourly values of diffuse solar radiation

    International Nuclear Information System (INIS)

    The study introduces a new regression model developed to estimate the hourly values of diffuse solar radiation at the surface. The model is based on the clearness index and diffuse fraction relationship, and includes the effects of cloud (cloudiness and cloud type), traditional meteorological variables (air temperature, relative humidity and atmospheric pressure observed at the surface) and air pollution (concentration of particulate matter observed at the surface). The new model is capable of predicting hourly values of diffuse solar radiation better than the previously developed ones (R2 = 0.93 and RMSE = 0.085). A simple version with a large applicability is proposed that takes into consideration cloud effects only (cloudiness and cloud height) and shows a R2 = 0.92.

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

    DEFF Research Database (Denmark)

    Plejdrup, Marlene Schmidt; Gyldenkærne, Steen

    2011-01-01

    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.

  16. 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)

  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. Helicopter air resonance modeling and suppression using active control

    Science.gov (United States)

    Takahashi, M. D.; Friedmann, P. P.

    1991-01-01

    A coupled rotor/fuselage helicopter analysis with the important effects of blade torsional flexibility, unsteady aerodynamics, and forward flight is presented. Using this mathematical model, a nominal configuration is selected with an air resonance instability throughout most of its flight envelope. A multivariable compensator is then designed using two swashplate inputs and a single-body roll rate measurement. The controller design is based on the linear quadratic Gaussian technique and the loop transfer recovery method. The controller is shown to suppress the air resonance instability throughout a wide range of helicopter loading conditions and forward flight speeds.

  19. 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.

  20. 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...

  1. Comparison of the performance of net radiation calculation models

    OpenAIRE

    Kjaersgaard, Jeppe Hvelplund; Cuenca, Richard Henry; Marti?nez-cob, Antonio; Gavila?n Zafra, Pedro; Plauborg, F. L.; Mollerup, M.; Hansen, S.

    2009-01-01

    Daily values of net radiation are used in many applications of crop-growth modeling and agricultural water management. Measurements of net radiation are not part of the routine measurement program at many weather stations and are commonly estimated based on other meteorological parameters. Daily values of net radiation were calculated using three net outgoing long-wave radiation models and compared to measured values. Four meteorological datasets representing two climate regimes, a sub-humid,...

  2. Measured, modelled and satellite derived solar radiation in Scandinavia

    OpenAIRE

    Hagen, Linda

    2011-01-01

    This article presents a comparison of global radiation data at different sites at the Scandinavian Peninsula. It makes use of ground truth, modelled and satellite derived surface global radiation data. First, a quality control of the ground truth data is conducted by evaluating measurements against the clear sky radiation estimated by a reliable model. Second, global radiation data derived from the geostationary satellite Meteosat are compared to the ground truth data.

  3. Convection and thermal radiation analytical models applicable to a nuclear waste repository room

    International Nuclear Information System (INIS)

    Time-dependent temperature distributions in a deep geologic nuclear waste repository have a direct impact on the physical integrity of the emplaced canisters and on the design of retrievability options. This report (1) identifies the thermodynamic properties and physical parameters of three convection regimes - forced, natural, and mixed; (2) defines the convection correlations applicable to calculating heat flow in a ventilated (forced-air) and in a nonventilated nuclear waste repository room; and (3) delineates a computer code that (a) computes and compares the floor-to-ceiling heat flow by convection and radiation, and (b) determines the nonlinear equivalent conductivity table for a repository room. (The tables permit the use of the ADINAT code to model surface-to-surface radiation and the TRUMP code to employ two different emissivity properties when modeling radiation exchange between the surface of two different materials.) The analysis shows that thermal radiation dominates heat flow modes in a nuclear waste repository room

  4. 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.

  5. Caenorhabditis elegans: a model to monitor bacterial air quality

    Directory of Open Access Journals (Sweden)

    Duclairoir Poc Cécile

    2011-11-01

    Full Text Available Abstract Background Low environmental air quality is a significant cause of mortality and morbidity and this question is now emerging as a main concern of governmental authorities. Airborne pollution results from the combination of chemicals, fine particles, and micro-organisms quantitatively or qualitatively dangerous for health or for the environment. Increasing regulations and limitations for outdoor air quality have been decreed in regards to chemicals and particles contrary to micro-organisms. Indeed, pertinent and reliable tests to evaluate this biohazard are scarce. In this work, our purpose was to evaluate the Caenorhaditis elegans killing test, a model considered as an equivalent to the mouse acute toxicity test in pharmaceutical industry, in order to monitor air bacterial quality. Findings The present study investigates the bacterial population in dust clouds generated during crop ship loading in harbor installations (Rouen harbor, Normandy, France. With a biocollector, airborne bacteria were impacted onto the surface of agar medium. After incubation, a replicate of the colonies on a fresh agar medium was done using a velvet. All the replicated colonies were pooled creating the "Total Air Sample". Meanwhile, all the colonies on the original plate were isolated. Among which, five representative bacterial strains were chosen. The virulence of these representatives was compared to that of the "Total Air Sample" using the Caenorhaditis elegans killing test. The survival kinetic of nematodes fed with the "Total Air Sample" is consistent with the kinetics obtained using the five different representatives strains. Conclusions Bacterial air quality can now be monitored in a one shot test using the Caenorhaditis elegans killing test.

  6. Potential radiation exposure due to volatile radionuclides released with the exhaust air during decommissioning operation of the Morsleben repository (ERAM)

    International Nuclear Information System (INIS)

    The licensing procedure for decommissioning operation of the ERAM repository requires a prediction on radioactive emissions through the exhaust air and the resulting potential radiation exposure. The emission of Tritium and C-14 emanating from the waste can be /derived from the radioactive inventory and the release rates determined experimentally. This procedure, however, cannot be applied to radon (Rn-222), which - together with its daughter products - is the predominant contributor to the potential radiation exposure. The reason is that there are other sources of radon apart from the Ra-226 inventory of the waste such as salt clay in the host rock, concrete and brick structures under ground as well as backfill material. The determination of the expected radon emission is based on measurements carried out while operating the repository in the past and on a numerical model that was matched with these measurements and taking into account additional radon sources. The results show that radon emissions from conventional mining activities in ERAM dominate over radon release from stored waste packages. (orig.)

  7. 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)

  8. 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...

  9. Model-based parameterisation of a hydrocyclone air-core

    Science.gov (United States)

    Podd; Schlaberg; Hoyle

    2000-03-01

    An important metric for the accurate control of a hydrocyclone is the diameter of its air-core. Ultrasonic data from a 16-transducer, 1.5 MHz pulse-echo tomographic system are analysed to determine the variation of the air-core diameter with various operating conditions. The back-projection image reconstruction method is not accurate enough for this task. Sub-millimetre accuracy is obtained, however, by applying a combination of signal processing and model-based reconstruction, using the fact that there is a small variation in the air-core boundary position. The findings correspond well to the results obtained from X-ray and electrical resistance modalities. PMID:10829775

  10. Principal component-based radiative transfer model for hyperspectral sensors: theoretical concept.

    Science.gov (United States)

    Liu, Xu; Smith, William L; Zhou, Daniel K; Larar, Allen

    2006-01-01

    Modern infrared satellite sensors such as the Atmospheric Infrared Sounder (AIRS), the Cross-Track Infrared Sounder (CrIS), the Tropospheric Emission Spectrometer (TES), the Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS), and the Infrared Atmospheric Sounding Interferometer (IASI) are capable of providing high spatial and spectral resolution infrared spectra. To fully exploit the vast amount of spectral information from these instruments, superfast radiative transfer models are needed. We present a novel radiative transfer model based on principal component analysis. Instead of predicting channel radiance or transmittance spectra directly, the principal component-based radiative transfer model (PCRTM) predicts the principal component (PC) scores of these quantities. This prediction ability leads to significant savings in computational time. The parameterization of the PCRTM model is derived from the properties of PC scores and instrument line-shape functions. The PCRTM is accurate and flexible. Because of its high speed and compressed spectral information format, it has great potential for superfast one-dimensional physical retrieval and for numerical weather prediction large volume radiance data assimilation applications. The model has been successfully developed for the NAST-I and AIRS instruments. The PCRTM model performs monochromatic radiative transfer calculations and is able to include multiple scattering calculations to account for clouds and aerosols. PMID:16422339

  11. 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

  12. 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 ?-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

  13. Modeling of the Lunar Radiation Environment

    International Nuclear Information System (INIS)

    In view of manned missions targeted to the Moon, for which radiation exposure is one of the greatest challenges to be tackled, it is of fundamental importance to have available a tool, which allows the determination of the particle flux and spectra at any time and at any point of the lunar surface. With this goal in mind, a new model of the Moon's radiation environment due to Galactic Cosmic Rays (GCR) and Solar Particle Events (SPE) has been developed. Primary particles reach the lunar surface, and are transported all throughout the subsurface layers, with backscattering patterns taken into account. The surface itself has been modeled as regolith and bedrock, with composition taken from the results of the instruments flown on the Apollo missions. Subsurface environments like lava tubes have been considered in the analysis. Particle transport has been performed with both deterministic and Monte Carlo codes with an adaptation for planetary surface geometry. Results are given in terms of fluxes, doses and LET, for most kinds of particles for various kinds of soil and rock chemical compositions

  14. A Review of Air Exchange Rate Models for Air Pollution Exposure Assessments

    Science.gov (United States)

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

  15. Role of personal air sampling in radiation safety programs and results of a laboratory evaluation of personal air-sampling equipment

    International Nuclear Information System (INIS)

    Recommended applications for personal air sampling in NRC licensee radiation protection programs are presented. The recommendations are based on performance tests of currently available samplers, a review of research and regulatory literature, and a survey of current licensee air-sampling programs. The performance tests show that personal air samplers are available which can provide a reliable, convenient means for breathing-zone sampling of workers in practically any work environment which might be encountered in the licensee industries. The research literature emphasized that estimates of an individual's exposure may be greatly underestimated if based on general area air samples, as is common practice in current licensee programs, due to the unpredictable variability of airborne-activity concentrations in the worksite. Research concerning the applicability of air-sampling measurements for estimating intake, uptake, and internal dose was also reviewed. These studies indicate that although breathing-zone activity measurements might provide the best (although not always accurate) means to estimate intake, estimates of uptake and internal dose usually should be made with bioassay or whole body counting. Other information on practical aspects of personal air sampling and related exposure control efforts are presented in the report. 27 refs., 15 figs., 18 tabs

  16. 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.

  17. Estimation of Pan Evaporation Using Mean Air Temperature and Radiation for Monsoon Season in Junagadh Region

    Directory of Open Access Journals (Sweden)

    Manoj J. Gundalia

    2013-11-01

    Full Text Available The abstract should summarize the content of the paper. Try to keep the abstract below 200 words. Do not make references nor display equations in the abstract. The journal will be printed from the same-sized copy prepared by you. Your manuscript should be printed on A4 paper (21.0 cm x 29.7 cm. It is imperative that the margins The significance of major meteorological factors, that influence the evaporation were evaluated at daily time-scale for monsoon season using the data from Junagadh station, Gujarat (India. The computed values were compared. The solar radiation and mean air temperature were found to be the significant factors influencing pan evaporation (Ep. The negative correlation was found between relative humidity and (Ep, while wind speed, vapour pressure deficit and bright sunshine hours were found least correlated and no longer remained controlling factors influencing (Ep. The objective of the present study is to compare and evaluate the performance of six different methods based on temperature and radiation to select the most appropriate equations for estimating (Ep. The three quantitative standard statistical performance evaluation measures, coefficient of determination (R2 root mean square of errors-observations standard deviation ratio (RSR and Nash-Sutcliffe efficiency coefficient (E are employed as performance criteria. The results show that the Jensen equation yielded the most reliable results in estimation of (Ep and it can be recommended for estimating (Ep for monsoon season in the study region.

  18. 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

  19. 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.)

  20. Air temperature, radiation budget and area changes of Quisoquipina glacier in the Cordillera Vilcanota (Peru)

    Science.gov (United States)

    Suarez, Wilson; Macedo, Nicolás; 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 Meteorología e Hidrología del Perú (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 développement (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.

  1. Modeling and Fluid Flow Analysis of Wavy Fin Based Automotive Radiator

    Directory of Open Access Journals (Sweden)

    Vishwa Deepak Dwivedi

    2015-01-01

    Full Text Available In continuous technological development, an automotive industry has increased the demand for high efficiency engines. A high efficiency engines in not only based on its performance but also for better fuel economy and less emission rate. Radiator is one of the important parts of the internal combustion engine cooling system. The manufacturing cost of the radiator is 20 percent of the whole cost of the engine. So improving the performance and reducing cost of radiators are necessary research. For higher cooling capacity of radiator, addition of fins is one of the approaches to increase the cooling rate of the radiator. In addition, heat transfer fluids at air and fluid side such as water and ethylene glycol exhibit very low thermal conductivity. As a result there is a need for new and innovative heat transfer fluids, known as “Nano fluid” for improving heat transfer rate in an automotive radiator. Recently there have been considerable research findings highlighting superior heat transfer performances of nanofluids about 15-25% of heat transfer enhancement can be achieved by using types of nanofluids. With these specific characteristics, the size and weight of an automotive car radiator can be reduced without affecting its heat transfer performance. An automotive radiator (Wavy fin type model is modeled on modeling software CATIA V5 and performance evaluation is done on pre-processing software ANSYS 14.0. The temperature and velocity distribution of coolant and air are analyzed by using Computational fluid dynamics environment software CFX. Results have shown that the rate of heat transfer is better when nano fluid (Si C + water is used as coolant, than the conventional coolant.

  2. Evaluation of Radiation Scheme Using Single Column Model

    Science.gov (United States)

    LEE, J.; Kang, J.; Jin, K.; Shin, D.; Kim, Y.

    2012-12-01

    Radiation scheme was analyzed and evaluated to provide the basis for the development of new radiation scheme which will be used in the next generation numerical weather prediction model. In this study, the performance of radiation scheme was evaluated through the single column model (SCM). SCM can be effectively used in the evaluation of physical parameterization scheme because it reduces calculation time and resources drastically by using single horizontal grid while using same physical processes and vertical resolution as global model's. ARM SGP-IOP data obtained in March 2000 were used as an initial and forcing data to run the model and to compare with model results. The model was run for 20 days from 17:30 UTC March 1 to17:30 UTC March 21, 2000 with calculation timestep of 900 s. The results showed that model was reasonably accurate for downward and upward shortwave radiation and downward longwave radiation at the surface for clear-sky conditions. However, downward shortwave radiation at the surface was underestimated compared to measurements when the model overestimated the amount of clouds. The reflected upward shortwave radiation at the surface was also underestimated by the reduced incoming shortwave radiation whereas the downward longwave radiation at the surface increased due to the increased presence of clouds. We performed sensitivity tests to assess the effect of variables on the calculation of radiative fluxes. Sensitivities were calculated for the radiation calculation timestep, scattering radiation calculation methods, cloud microphysics schemes, different approaches to the freezing at the top of clouds, different treatments of cloud phase, and aerosols. For those variables, high sensitivity was shown depending on the use of different cloud microphysics scheme and aerosol so that radiation scheme which accurately simulates the interaction between cloud, aerosol, and radiation should be developed.

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

    Directory of Open Access Journals (Sweden)

    E. Carvalho

    2000-12-01

    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.

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

    Scientific Electronic Library Online (English)

    E., Carvalho; E., Camarasa; L.A.C., Meleiro; R., Maciel Filho; A., Domingues; Ch., Vial; G., Wild; S., Poncin; N., Midoux; J., Bouillard.

    2000-12-01

    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 dis [...] tributors 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.

  5. Flavour dependent gauged radiative neutrino mass model

    Science.gov (United States)

    Baek, Seungwon; Okada, Hiroshi; Yagyu, Kei

    2015-04-01

    We propose a one-loop induced radiative neutrino mass model with anomaly free flavour dependent gauge symmetry: ? minus ? symmetry U(1) ?- ? . A neutrino mass matrix satisfying current experimental data can be obtained by introducing a weak isospin singlet scalar boson that breaks U(1) ?- ? 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 from 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 additional neutral gauge boson loop contribution with mass of order 100 MeV and new gauge coupling of order 10-3.

  6. A Neural Network Based Intelligent Predictive Sensor for Cloudiness, Solar Radiation and Air Temperature

    OpenAIRE

    Pedro M. Ferreira; Ruano, António E.; Gomes, João M.; 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 the a...

  7. 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.)

  8. Integrable Models of Interaction of Matter with Radiation

    Directory of Open Access Journals (Sweden)

    Vladimir I. Inozemtsev

    2006-10-01

    Full Text Available The simplified models of interaction of charged matter with resonance modes of radiation generalizing the well-known Jaynes-Cummings and Dicke models are considered. It is found that these new models are integrable for arbitrary numbers of dipole sources and resonance modes of the radiation field. The problem of explicit diagonalisation of corresponding Hamiltonians is discussed.

  9. Mathematical modeling of a primary zinc/air battery

    Science.gov (United States)

    Mao, Z.; White, R. E.

    1992-01-01

    The mathematical model developed by Sunu and Bennion has been extended to include the separator, precipitation of both solid ZnO and K2Zn(OH)4, and the air electrode, and has been used to investigate the behavior of a primary Zn-Air battery with respect to battery design features. Predictions obtained from the model indicate that anode material utilization is predominantly limited by depletion of the concentration of hydroxide ions. The effect of electrode thickness on anode material utilization is insignificant, whereas material loading per unit volume has a great effect on anode material utilization; a higher loading lowers both the anode material utilization and delivered capacity. Use of a thick separator will increase the anode material utilization, but may reduce the cell voltage.

  10. 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...

  11. 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.

  12. 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...

  13. 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.

  14. A diffusion model for antiprotons and protons of cosmic radiation

    International Nuclear Information System (INIS)

    One target was to explain antiprotons in cosmic radiation. These particles are of special interest because they cannot or only partially be described by the classic propagation models of cosmic radiation. On the other hand, however, the nuclei flows as calculated by the ''leaky-box'' model show good correlation with the measured follow of the nuclei in cosmic radiation. The thesis also deals with the interpretation of the radial decrease of the proton flow of cosmic radiation in the galaxies (gradient) and the way in which this is connected to antiprotons. The leaky-box model assumes a monogeneous distribution of cosmic radiation in ghe galaxies, so that this gradient is a contradiction to the basic assumption of the leaky-box model. According to relevant observation results in the area of cosmic radiation a diffusion model is proposed which is locally independent and still simple enough to produce a random gradient needed for observation. (orig.)

  15. 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 ? ?T ? 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 Rayom 1 K to 5 K. ? Critical Rayleigh numbers are considerably increased by radiation. ? According to the thermal boundary conditions, combined analyses are required.

  16. Modelling radiation-induced cell cycle delays

    OpenAIRE

    Ochab-Marcinek, Anna; Gudowska-Nowak, Ewa; Nasonova, Elena; Ritter, Sylvia

    2009-01-01

    Ionizing radiation is known to delay the cell cycle progression. In particular after particle exposure significant delays have been observed and it has been shown that the extent of delay affects the expression of damage such as chromosome aberrations. Thus, to predict how cells respond to ionizing radiation and to derive reliable estimates of radiation risks, information about radiation-induced cell cycle perturbations is required. In the present study we describe and apply...

  17. Vehicular Air Pollution Modeling For Diesel Driven Vehicles

    Directory of Open Access Journals (Sweden)

    S.Arul selvan

    2014-08-01

    Full Text Available Pollution in air is generated by the developments, which typically occur as the country gradually shifts towards industrialization, due to city growth, increasing traffic, rapid economic development, and higher levels of energy consumption. Indian cities are among the most polluted cities in the world. The main source of air pollution in Indian metropolitan cities is petrol and diesel driven vehicles. They particularly emit CO, CO2, HC, NOX and O2. The growing vehicular population has resulted in increased air pollution, which in turn has affected the people’s health, who live along the transportation corridors. Increase in vehicular population, has resulted in decrease in quality of air and the environment. There are several health impacts that are associated with respiratory infections, asthma etc,. A number of studies have been done by the foreign countries, but this is not suitable for the Indian cities. This may be due to heterogeneity of vehicles, multiplicity of modes and the difference in geometrics of road. Therefore the need arises to study about the emission rates. In this study, equipment by the name five gas analyzer is used to find out the emission rates of different types of vehicles under static and dynamic conditions. The factor considered under static conditions is the age of the vehicles. Whereas under dynamic condition factors considered are the road roughness, age of the vehicle and speed. From the emission rates a linear regression model is developed using SPSS software and sensitivity analysis is being carried out.

  18. 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.

  19. 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)

  20. AIR INGRESS ANALYSIS: PART 2 – COMPUTATIONAL FLUID DYNAMIC MODELS

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-01-01

    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.

  1. Comparison of the performance of net radiation calculation models

    DEFF Research Database (Denmark)

    Kjærsgaard, Jeppe Hvelplund; Cuenca, R H

    2009-01-01

    Daily values of net radiation are used in many applications of crop-growth modeling and agricultural water management. Measurements of net radiation are not part of the routine measurement program at many weather stations and are commonly estimated based on other meteorological parameters. Daily values of net radiation were calculated using three net outgoing long-wave radiation models and compared to measured values. Four meteorological datasets representing two climate regimes, a sub-humid, high-latitude environment and a semi-arid mid-latitude environment, were used to test the models. The long-wave radiation models included a physically based model, an empirical model from the literature, and a new empirical model. Both empirical models used only solar radiation as required for meteorological input. The long-wave radiation models were used with model calibration coefficients from the literature and with locally calibrated ones. A measured, average albedo value of 0.25 was used at the high-latitude sites. A fixed albedo value of 0.25 resulted in less bias and scatter at the mid-latitude sites compared to other albedo values. When used with model coefficients calibrated locally or developed for specific climate regimes, the predictions of the physically based model had slightly lower bias and scatter than the empirical models. When used with their original model coefficients, the physically based model had a higher bias than the measurement error of the net radiation instruments used. The performance of the empirical models was nearly identical at all sites. Since the empirical models were easier to use and simpler to calibrate than the physically based models, the results indicate that the empirical models can be used as a good substitute for the physically based ones when available meteorological input data is limited. Model predictions were found to have a higher bias and scatter when using summed calculated hourly time steps compared to using daily input data.

  2. Air quality over Europe: modelling gaseous and particulate pollutants

    OpenAIRE

    Tagaris, E.; Sotiropoulou, R. E. P.; Gounaris, N.; Andronopoulos, S.; Vlachogiannis, D.

    2013-01-01

    Air quality over Europe using Models-3 (i.e., CMAQ, MM5, SMOKE) modelling system is performed for winter (i.e., January 2006) and summer (i.e., July 2006) months with the 2006 TNO gridded anthropogenic emissions database. Higher ozone mixing ratios are predicted in southern Europe while higher NO2 levels are simulated over western Europe. Elevated SO2 values are simulated over eastern Europe and higher PM2.5 concentrations over eastern and western Europe. Regional average results suggest that...

  3. Discrete-Choice Models and Their Application to Air Transportation

    Directory of Open Access Journals (Sweden)

    Marina Ciarlini

    2008-01-01

    Full Text Available This paper provides a review on discrete choice theory with emphasis on the approach provided by Ken Train (2003 in Discrete Choice Methods with Simulation. General theoretical aspects of this approach will be presented along with the characteristics of the main models, Logit and Probit. In the end, an application of a discrete choice model in passenger air transportation, based on the Boguslaski, Ito and Lee study, Entry patterns in the Southwest Airlines route system, published in Review of Industrial Organization in 2004, will be described.[Paper in Portuguese

  4. Development of IIT air quality model for industrial use

    Energy Technology Data Exchange (ETDEWEB)

    Mohan, M. [Indian Institute of Technology, New Delhi (India); Siddiqui, T.A. [Engineers India Limited, Guragaon (India)

    1996-12-31

    In the present study a mathematical model named UT Air quality (IITAQ) model has been developed which essentially retains all the desired features of a Gaussian model and at the same time overcomes most of the disadvantages associated with these Gaussian models. The proposed model is a numerical box model which incorporates sophistication with better or improved parameterization of the physical processes in the Atmospheric Boundary Layer and at the same time avoids the disadvantages of 3-D numerical models with detailed physics of ABL. The model uses the more realistic and easily adoptable input parameters. The estimation of these and model formulation have been discussed at length for the elevated source during all kinds of stability conditions. The main parameters namely wind and eddy diffusitivity profiles and dispersion coefficient make extensive use of Monin-Obukhov similarity theory. The model also incorporates latest formulation of plume rise and plume penetration. The estimated hourly Ground Level Concentration (GLC) have been compared with SF{sub 6} tracer diffusion experiments. The validation shows that the estimated concentration from IITAQ model are in good agreement with the observed values. The various statistical parameters have been estimated to truly assess the model performance.

  5. Time-based collision risk modeling for air traffic management

    Science.gov (United States)

    Bell, Alan E.

    Since the emergence of commercial aviation in the early part of last century, economic forces have driven a steadily increasing demand for air transportation. Increasing density of aircraft operating in a finite volume of airspace is accompanied by a corresponding increase in the risk of collision, and in response to a growing number of incidents and accidents involving collisions between aircraft, governments worldwide have developed air traffic control systems and procedures to mitigate this risk. The objective of any collision risk management system is to project conflicts and provide operators with sufficient opportunity to recognize potential collisions and take necessary actions to avoid them. It is therefore the assertion of this research that the currency of collision risk management is time. Future Air Traffic Management Systems are being designed around the foundational principle of four dimensional trajectory based operations, a method that replaces legacy first-come, first-served sequencing priorities with time-based reservations throughout the airspace system. This research will demonstrate that if aircraft are to be sequenced in four dimensions, they must also be separated in four dimensions. In order to separate aircraft in four dimensions, time must emerge as the primary tool by which air traffic is managed. A functional relationship exists between the time-based performance of aircraft, the interval between aircraft scheduled to cross some three dimensional point in space, and the risk of collision. This research models that relationship and presents two key findings. First, a method is developed by which the ability of an aircraft to meet a required time of arrival may be expressed as a robust standard for both industry and operations. Second, a method by which airspace system capacity may be increased while maintaining an acceptable level of collision risk is presented and demonstrated for the purpose of formulating recommendations for procedures regulating air traffic management methods and industry standards governing performance requirements for avionics designed to support trajectory based operations.

  6. 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

  7. Atmospheric radiative transfer modeling: a summary of the AER codes

    Science.gov (United States)

    Clough, S. A.; Shephard, M. W.; Mlawer, E. J.; Delamere, J. S.; Iacono, M. J.; Cady-Pereira, K.; Boukabara, S.; Brown, P. D.

    2005-03-01

    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, RRTM_LW and RRTM_SW; the Monochromatic Radiative Transfer Model (MonoRTM); the MT_CKD 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.

  8. 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 dootential to provide suitable quality 3D dosimetry measurements for external beam dose verification, while offering significant advantages in convenience and efficiency for routine use.

  9. GREEN RIVER AIR QUALITY MODEL DEVELOPMENT. MELSAR - A MESOSCALE AIR QUALITY MODEL FOR COMPLEX TERRAIN. VOLUME 1. OVERVIEW, TECHNICAL DESCRIPTION AND USER'S GUIDE

    Science.gov (United States)

    MELSAR, a mesoscale air quality model, was developed for predicting air pollutant concentrations resulting from releases from multiple sources. The model is a Lagrangian puff model for application in complex terrain, principally at long source-to-receptor transport distances (ten...

  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. 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%

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

    OpenAIRE

    B. Safari; J. Gasore

    2009-01-01

    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 squ...

  13. Higgs inflation in a radiative seesaw model

    International Nuclear Information System (INIS)

    We investigate a simple model to explain inflation, neutrino masses and dark matter simultaneously. This is based on the so-called radiative seesaw model proposed by E. Ma in order to explain neutrino masses and dark matter by introducing a Z2-odd isospin doublet scalar field and Z2-odd right-handed neutrinos. We study the possibility that the Higgs boson as well as neutral components of the Z2-odd scalar doublet field can satisfy conditions from slow-roll inflation and vacuum stability up to the inflation scale. We find that a part of parameter regions where these scalar fields can play a role of an inflaton is compatible with the current data from neutrino experiments and those of the dark matter abundance as well as the direct search results. A phenomenological consequence of this scenario results in a specific mass spectrum of scalar bosons, which can be tested at the LHC, the International Linear Collider and the Compact Linear Collider

  14. Radiative symmetry breaking in brane models

    International Nuclear Information System (INIS)

    We propose a way to generate the electroweak symmetry breaking radiatively in non-supersymmetric type I models with string scale in the TeV region. By identifying the Higgs field with a tree-level massless open string state, we find that a negative squared mass term can be generated at one loop. It is finite, computable and typically a loop factor smaller than the string scale, that acts as an ultraviolet cutoff in the effective field theory. When the Higgs open string has both ends confined on our world brane, its mass is predicted to be around 120 GeV, i.e., that of the lightest Higgs in the minimal supersymmetric model for large tan? and mA. Moreover, the string scale turns out to be one to two orders of magnitude higher than the weak scale. We also discuss possible effects of higher order string threshold corrections that might increase the string scale and the Higgs mass

  15. Air pollutants and energy pathways; Extending models for abatement strategies

    International Nuclear Information System (INIS)

    This study presents the development and applications of regional and local scale models for use in integrated assessment of air pollution effects in conjunction with large-scale models. A regional deposition model called DAIQUIRI (Deposition, AIr QUality and Integrated Regional Information) for integrated assessment purposes in Finland was constructed, and regional matrices for nitrogen oxides and ammonia were developed from the results of the regional air quality model of the FMI. DAIQUIRI produced similar estimates of deposition from Finnish sources as the original model, and long-term trends and the average level of deposition estimated with DAIQUIRI were found comparable with the monitored deposition levels and trends. For the mid-nineties situation, the regional nitrogen modeling resulted in 9 % to 19 % (depending on the region compared) larger estimates of areas with acidity critical load exceedances than when using European scale nitrogen deposition modeling. In this work, also a method for estimating the impacts of local NOx emissions on urban and sub-urban ozone levels was developed and tested. The study concentrated on representing the destruction of ozone by fresh NO emissions in urban areas for future use in integrated assessment modeling of ozone control strategies. Correlation coefficients between measured daytime ozone values in the study area were found to improve from 0.64 (correlation between urban and surrounding rural measurements) to 0. and surrounding rural measurements) to 0.85, on the average. The average correlation between daytime large-scale model estimates and urban site measurements was found to improve from 0.37 to 0.58. In the study, also integrated assessment model applications were carried out at European, national and local levels. The synergies between control strategies for CO2 and acidification and ozone formation in the case of the UN/FCCC Kyoto protocol and the air quality targets of the EU were assessed with the help of coupled models. With two alternative energy scenarios reflecting the Kyoto targets for CO2, reductions of sulfur and NOx emissions between 12 % and 22 % and 8 % to 12 %, respectively, were estimated by 2010 in the EU-15 with the present emission control legislation. Due to the lower activity levels generating less emissions and the cleaner energy forms used, 35-43 % cost savings in further technical emission controls required for achieving the EU air quality targets would be achieved with the scenarios studied. Case studies for Finland indicated that there has been a decrease of 60 % in the area at risk of acidification from 1990 to 1995, and that the declining trend is expected to continue due to the recent international emission reduction agreements within the UN/ECE and the EU. Implementation of the Kyoto protocol in Finland and in the whole of EU-15 (with the present emission legislation) could bring up to 8 % more reduction of ecosystems at risk of acidification in Finland by 2010 than the recent UN/ECE protocol. An uncertainty analysis of acidification integrated assessment modeling in Finland indicated that critical loads dominate the uncertainty. Estimates are becoming more robust, as the general level of deposition is decreasing. In Finland, further efforts to reduce the overall uncertainty should be mainly directed to more accurate description of critical thresholds. In areas affected by major nearby emission sources, also uncertainties in emissions and deposition are significant. The models and their applications presented in this study contributed to identifying the problem characteristics and have supported environmental policy development at international, national and regional levels. (orig.)

  16. USE OF REMOTE SENSING AIR QUALITY INFORMATION IN REGIONAL SCALE AIR POLLUTION MODELING: CURRENT USE AND REQUIREMENTS

    Science.gov (United States)

    In recent years the applications of regional air quality models are continuously being extended to address atmospheric pollution phenomenon from local to hemispheric spatial scales over time scales ranging from episodic to annual. The need to represent interactions between physic...

  17. 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

  18. 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

  19. Evaluation of air temperature distribution using thermal image under conditions of nocturnal radiative cooling in winter season over Shikoku area

    International Nuclear Information System (INIS)

    Using the thermal images offered by the infra-red thermometer and the LANDSAT, the air temperature distribution over mountainous regions were estimated under conditions of nocturnal radiative cooling in the winter season. The thermal image analyses by using an infra-red thermometer and the micrometeological observation were carried out around Zentsuji Kagawa prefecture. At the same time, the thermal image analyses were carried out by using the LANDSAT data. The LANDSAT data were taken on Dec. 7, 1984 and Dec. 5, 1989. The scenes covered the west part of Shikoku, southwest of Japan.The results were summarized as follows:Values of the surface temperature of trees, which were measured by an infra-red thermometer, were almost equal to the air temperature. On the other hand, DN values detected by LANDSAT over forest area were closely related with air temperature observed by AMeDAS. Therefore, it is possible to evaluate instantaneously a spatial distribution of the nocturnal air temperature from thermal image.The LANDSAT detect a surface temperature over Shikoku area only at 21:30. When radiative cooling was dominant, the thermal belt and the cold air lake were already formed on the mountain slopes at 21:30. Therfore, it is possible to estimate the characteristic of nocturnal temperature distribution by using LANDSAT data.It became clear that the temperature distribution estimated by thermal images offered by the infra-red thermometer and the LANDSAT was useful for the evaluation of rational land use for winter crops

  20. Air quality modeling in the Valley of Mexico: meteorology, emissions and forecasting

    Science.gov (United States)

    Garcia-Reynoso, A.; Jazcilevich, A. D.; Diaz-Nigenda, E.; Vazquez-Morales, W.; Torres-Jardon, R.; Ruiz-Suarez, G.; Tatarko, J.; Bornstein, R.

    2007-12-01

    The Valley of Mexico presents important challenges for air quality modeling: complex terrain, a great variety of anthropogenic and natural emissions sources, and high altitude and low latitude increasing the amount of radiation flux. The modeling group at the CCA-UNAM is using and merging state of the art models to study the different aspects that influence the air quality phenomenon in the Valley of Mexico. The air quality model MCCM that uses MM5 as its meteorological input has been a valuable tool to study important features of the complex and intricate atmospheric flows on the valley, such as local confluences and vertical fumigation. Air quality modeling has allowed studying the interaction between the atmospheres of the valleys surrounding the Valley of Mexico, prompting the location of measurement stations during the MILAGRO campaign. These measurements confirmed the modeling results and expanded our knowledge of the transport of pollutants between the Valleys of Cuernavaca, Puebla and Mexico. The urban landscape of Mexico City complicates meteorological modeling. Urban-MM5, a model that explicitly takes into account the influence of buildings, houses, streets, parks and anthropogenic heat, is being implemented. Preliminary results of urban-MM5 on a small area of the city have been obtained. The current emissions inventory uses traffic database that includes hourly vehicular activity in more than 11,000 street segments, includes 23 area emissions categories, more than 1,000 industrial sources and biogenic emissions. To improve mobile sources emissions a system consisting of a traffic model and a car simulator is underway. This system will allow for high time and space resolution and takes into account motor stress due to different driving regimes. An important source of emissions in the Valley of Mexico is erosion dust. The erosion model WEPS has been integrated with MM5 and preliminary results showing dust episodes over Mexico City have been obtained. A real time Ozone forecast model is being implemented for the Valley of Mexico whose performance is being evaluated.

  1. Air Quality Modeling in Support of the Near-Road Exposures and Effects of Urban Air Pollutants Study (NEXUS

    Directory of Open Access Journals (Sweden)

    Vlad Isakov

    2014-08-01

    Full Text Available A major challenge in traffic-related air pollution exposure studies is the lack of information regarding pollutant exposure characterization. Air quality modeling can provide spatially and temporally varying exposure estimates for examining relationships between traffic-related air pollutants and adverse health outcomes. A hybrid air quality modeling approach was used to estimate exposure to traffic-related air pollutants in support of the Near-Road Exposures and Effects of Urban Air Pollutants Study (NEXUS conducted in Detroit (Michigan, USA. Model-based exposure metrics, associated with local variations of emissions and meteorology, were estimated using a combination of the American Meteorological Society/Environmental Protection Agency Regulatory Model (AERMOD and Research LINE-source dispersion model for near-surface releases (RLINE dispersion models, local emission source information from the National Emissions Inventory, detailed road network locations and traffic activity, and meteorological data from the Detroit City Airport. The regional background contribution was estimated using a combination of the Community Multi-scale Air Quality (CMAQ and the Space-Time Ordinary Kriging (STOK models. To capture the near-road pollutant gradients, refined “mini-grids” of model receptors were placed around participant homes. Exposure metrics for CO, NOx, PM2.5 and its components (elemental and organic carbon were predicted at each home location for multiple time periods including daily and rush hours. The exposure metrics were evaluated for their ability to characterize the spatial and temporal variations of multiple ambient air pollutants compared to measurements across the study area.

  2. Radiation policy: a decision-making model.

    OpenAIRE

    Modan, B

    1997-01-01

    Priority setting in radiation policy is complex because it depends to a large extent on risk perception. It has been shown repeatedly that the public is much more sensitive to potential harmful sequelae of radiation than to those of other environmental pollutants. Thus, cancer risk, particularly at low doses, has become a sociopolitical issue. The principle that radiation causes cancer, is life shortening, and causes an array of other pathologic disorders, is well accepted yet the quantificat...

  3. Radiation studies with a high-resolution mesoscale model

    International Nuclear Information System (INIS)

    The paramaterization of radiation in general circulation models (GCMs) relies strongly on correctly representing the mean radiative properties over a typical grid size. The quality of the model's feedback between clouds and radiation would depend on the accuracy of this representation; this feedback is a key factor in determining the climate's behavior under various future scenarios. The use of a mesoscale model allows both clouds and radiation to receive a high-resolution treatment that can be free of the assumptions of overlapping and cloud fraction. To this end, the newest version of the Penn State/National Center for Atmospheric Research (NCAR) Mesoscale Model (MM5) has been upgraded to include a radiation package. Here the model is introduced and preliminary results are shown. Of particular interest are the domain-averaged properties of a cloud system as it evolves during one diurnal cycle

  4. Application of SIM-air modeling tools to assess air quality in Indian cities

    Science.gov (United States)

    Guttikunda, Sarath K.; Jawahar, Puja

    2012-12-01

    A prerequisite to an air quality management plan for a city is some idea of the main sources of pollution and their contributions for a city. This paper presents the results of an application of the SIM-air modeling tool in six Indian cities - Pune, Chennai, Indore, Ahmedabad, Surat, and Rajkot. Using existing and publicly available data, we put together a baseline of multi-pollutant emissions for each of the cities and then calculate concentrations, health impacts, and model alternative scenarios for 2020. The measured annual PM10 (particulate matter with aerodynamic diameter less than 10 micron meter) concentrations in ?g m-3 averaged 94.7 ± 45.4 in Pune, 73.1 ± 33.7 in Chennai, 118.8 ± 44.3 in Indore, 94.0 ± 20.4 in Ahmedabad, 89.4 ± 12.1 in Surat, and 105.0 ± 25.6 in Rajkot, all exceeding the annual standard of 60 ?g m-3. The PM10 inventory in tons/year for the year 2010 of 38,400 in Pune, 50,200 in Chennai, 18,600 in Indore, 31,900 in Ahmedabad, 20,000 in Surat, and 14,000 in Rajkot, is further spatially segregated into 1 km grids and includes all known sources such as transport, road dust, residential, power plants, industries (including the brick kilns), waste burning, and diesel generator sets. We use the ATMoS chemical transport model to validate the emissions inventory and estimate an annual premature mortality due to particulate pollution of 15,200 for the year 2010 for the six cities. Of the estimated 21,400 premature deaths in the six cities in 2020, we estimate that implementation of the six interventions in the transport and brick kiln sectors, can potentially save 5870 lives (27%) annually and result in an annual reduction of 16.8 million tons of carbon dioxide emissions in the six cities.

  5. 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

  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. Application of receptor modeling to indoor air emissions from electroplating

    Energy Technology Data Exchange (ETDEWEB)

    Wadden, R.A.; Liao, S.L.; Scheff, P.A.; Franke, J.E.; Conroy, L.M. [Univ. of Illinois, Chicago, IL (United States). School of Public Health

    1998-12-01

    In work areas containing multiple sources of the same air pollutant, it is useful for control purposes to be able to separate out the contribution from each individual source. In this study, the chemical mass balance (CMB) receptor model was used to allocate the contributions from multiple sources to area concentration measurements in three electroplating shops. Shop 1 was a room with a single copper electroplating line; shop 2 was a large bay containing a chromium conversion coating line, a continuous chromium electroplating line, and several manual electroplating operations; shop 3 contained a piston chrome plating line, a decorative chrome plating line, and manual and barrel zinc coating lines. The receptor modeling approach uses the elemental composition of one or more source categories to determine what fraction of an area sample is contributed by each source. In most cases the CMB model predicted over 90% of the measured concentrations. The allocation procedure explained 100% of the copper measured at three locations in shop 1, with contributions of 95 to 98% from the plating line and the rest from air outside the room. For shop 2, a two-source model explained 100% of the chromium measured at five sampling locations. For shop 3, the percent contributions of chromium from the piston plating line and the decorative plating line were consistent with distance from each of the sources.

  8. Mathematical modeling of radiating defects in iron

    Directory of Open Access Journals (Sweden)

    A. Kupchishin

    2012-12-01

    Full Text Available Processes of radiation formation of defects in the iron exposed to radiation by various ions are considered in the work. The algorithm is developed for calculation of cascadely - probabilistic functions, concentration of radiation defects, computations are lead, the regularities  arising at calculations of cascadely - probabilistic functions depending on number of interactions and depth of penetration of particles, concentration of radiation  defects are revealed by an ionic irradiation in iron. Results of calculations are presented in the form of tables and schedules.

  9. On the possibility of a short subterahertz pulse amplification in a plasma channel created in air by intense laser radiation

    International Nuclear Information System (INIS)

    The evolution of the electron energy distribution function in the plasma channel created in air by a UV-laser pulse of femtosecond duration is studied. It is shown that such a channel can be used to amplify few-cycle electromagnetic pulses in the subterahertz frequency range at the time of relaxation of the energy spectrum in air determined by the vibrational excitation of the nitrogen molecules. The gain factor as a function of time, electron concentration and frequency of the amplifying radiation is obtained. The propagation of few-cycle radio-frequency pulses through the amplifying medium is analysed. (paper)

  10. Search for molecular bremsstrahlung radiation signals in Ku band with coincidental operations of radio telescopes with air shower detectors

    Directory of Open Access Journals (Sweden)

    Fukushima Masaki

    2013-06-01

    Full Text Available 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 experiment, and we operated the radio telescopes coincidentally with FD event triggers. We report the experimental setups and the results of these measurements.

  11. 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 ...

  12. 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 (...

  13. Research on Dependable Ionizing Radiation Protection based on Model i*

    Directory of Open Access Journals (Sweden)

    Tan Hai

    2013-07-01

    Full Text Available The software’s unreliability mostly attributes to an erroneous analysis on the requirements done at the beginning. In this paper, we apply the tool of i* frame requirement modeling and build early requirement model against ionizing radiation. After finding out possible risks and corresponding solutions during the process of modeling analysis, we propose reasoning models against ionizing radiation. The radiation protection system  with  the  above models  can  figure out  the  purpose  of agents  related  to radiant source and provide normal service even when the environment software system is being interfered. It can serve the ecological and economical society with stability and development.  The model is divided into several sections. Section 1 gives the outline of the dependant software. Section 2 illustrates the  i* frame  technology. Section 3, 4 and 5 cover the topic of dependant security requirement analysis, SD&SR model on ionizing radiation respectively. Section 6 gives the conclusion.

  14. 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...

  15. CONTINUED RESEARCH IN MESOSCALE AIR POLLUTION SIMULATION MODELING. VOLUME 7. MATHEMATICAL MODELING OF URBAN AEROSOL DYNAMICS

    Science.gov (United States)

    A simplified model of the dynamics of photochemical aerosols is developed, and initial applications are presented. The model, which can be incorporated in or coupled to a photochemical air quality simulation model, takes into consideration the emissions of particles with diameter...

  16. 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

    2004-01-01

    Measured solar radiation data are most commonly available as total solar radiation on a horizontal surface. When using solar radiation measured on horizontal to calculate the solar radiation on tilted surfaces and thereby the thermal performance of different applications such as buildings and solar 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 distributed over the entire sky dome and calculated as pure isotropic radiation or by anisotropic radiation models that also uses contribution from circumsolar radiation in the calculation or by anisotropic radiation models that apart from the isotropic and circumsolar contribution uses horizon brightening in the calculation. The weather data are measured at the solar radiation measurement station, SMS at the Departmentof Civil Engineering at the Technical University of Denmark. In this study the weather data are combined with solar collector calculations based on solar collector test carried out at Solar Energy Center, SEC, Denmark. With measured solar radiation on horizontal and the different solar radiation processing models the total radiation is calculated on differently tilted and oriented surfaces and compared with the measured solar radiation on the different surfaces. Further, the impact on the 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.

  17. THE EMERGENCE OF NUMERICAL AIR QUALITY FORECASTING MODELS AND THEIR APPLICATION

    Science.gov (United States)

    In recent years the U.S. and other nations have begun programs for short-term local through regional air quality forecasting based upon numerical three-dimensional air quality grid models. These numerical air quality forecast (NAQF) models and systems have been developed and test...

  18. 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.

  19. A comparison of self reported air pollution problems and GIS-modeled levels of air pollution in people with and without chronic diseases

    OpenAIRE

    Nafstad Per; Næss Øyvind; Madsen Christian; Piro Fredrik; Claussen Bjørgulf

    2008-01-01

    Abstract Objective To explore various contributors to people's reporting of self reported air pollution problems in area of living, including GIS-modeled air pollution, and to investigate whether those with respiratory or other chronic diseases tend to over-report air pollution problems, compared to healthy people. Methods Cross-sectional data from the Oslo Health Study (2000–2001) were linked with GIS-modeled air pollution data from the Norwegian Institute of Air Research. Multivariate reg...

  20. Radiative forcing by long-lived greenhouse gases: Calculations with the AER radiative transfer models

    Science.gov (United States)

    Iacono, Michael J.; Delamere, Jennifer S.; Mlawer, Eli J.; Shephard, Mark W.; Clough, Shepard A.; Collins, William D.

    2008-07-01

    A primary component of the observed recent climate change is the radiative forcing from increased concentrations of long-lived greenhouse gases (LLGHGs). Effective simulation of anthropogenic climate change by general circulation models (GCMs) is strongly dependent on the accurate representation of radiative processes associated with water vapor, ozone, and LLGHGs. In the context of the increasing application of the Atmospheric and Environmental Research, Inc. (AER), radiation models within the GCM community, their capability to calculate longwave and shortwave radiative forcing for clear sky scenarios previously examined by the radiative transfer model intercomparison project (RTMIP) is presented. Forcing calculations with the AER line-by-line (LBL) models are very consistent with the RTMIP line-by-line results in the longwave and shortwave. The AER broadband models, in all but one case, calculate longwave forcings within a range of -0.20 to 0.23 W m-2 of LBL calculations and shortwave forcings within a range of -0.16 to 0.38 W m-2 of LBL results. These models also perform well at the surface, which RTMIP identified as a level at which GCM radiation models have particular difficulty reproducing LBL fluxes. Heating profile perturbations calculated by the broadband models generally reproduce high-resolution calculations within a few hundredths K d-1 in the troposphere and within 0.15 K d-1 in the peak stratospheric heating near 1 hPa. In most cases, the AER broadband models provide radiative forcing results that are in closer agreement with high-resolution calculations than the GCM radiation codes examined by RTMIP, which supports the application of the AER models to climate change research.

  1. Modeling and Analysis of Aluminum/Air Fuel Cell

    Science.gov (United States)

    Leon, Armando J.

    The technical and scientific challenges to provide reliable sources energy for US and global economy are enormous tasks, and especially so when combined with strategic and recent economic concerns of the last five years. It is clear that as part of the mix of energy sources necessary to deal with these challenges, fuel cells technology will play critical or even a central role. The US Department of Energy, as well as a number of the national laboratories and academic institutions have been aware of the importance such technology for some time. Recently, car manufacturers, transportation experts, and even utilities are paying attention to this vital source of energy for the future. In this thesis, a review of the main fuel cell technologies is presented with the focus on the modeling, and control of one particular and promising fuel cell technology, aluminum air fuel cells. The basic principles of this fuel cell technology are presented. A major part of the study consists of a description of the electrochemistry of the process, modeling, and simulations of aluminum air FC using Matlab Simulink(TM). The controller design of the proposed model is also presented. In sequel, a power management unit is designed and analyzed as an alternative source of power. Thus, the system commutes between the fuel cell output and the alternative power source in order to fulfill a changing power load demand. Finally, a cost analysis and assessment of this technology for portable devices, conclusions and future recommendations are presented.

  2. 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.

  3. Modeling the extrafocal radiation and monitor chamber backscatter for photon beam dose calculation

    International Nuclear Information System (INIS)

    A simple analytical approach has been developed to model extrafocal radiation and monitor chamber backscatter for clinical photon beams. Model parameters for both the extrafocal source and monitor chamber backscatter are determined simultaneously using conventional measured data, i.e., in-air output factors for square and rectangular fields defined by the photon jaws. The model has been applied to 6 MV and 15 MV photon beams produced by a Varian Clinac 2300C/D accelerator. Contributions to the in-air output factor from the extrafocal radiation and monitor chamber backscatter, as predicted by the model, are in good agreement with the measurements. The model can be used to calculate the in-air output factors analytically, with an accuracy of 0.2% for symmetric or asymmetric rectangular fields defined by jaws when the calculation point is at the isocenter and 0.5% when the calculation point is at an extended SSD. For MLC-defined fields, with the jaws at the recommended positions, calculated in-air output factors agree with the measured data to within 0.3% at the isocenter and 0.7% at off-axis positions. The model has been incorporated into a Monte Carlo dose algorithm to calculate the absolute dose distributions in patients or phantoms. For three MLC-defined irregular fields (triangle shape, C-shape, and L-shape), the calculations agree with the measurements to about 1% even for points at off-axis positions. The model will be particularly useful for IMRT dose calculationticularly useful for IMRT dose calculations because it accurately predicts beam output and penumbra dose

  4. Directed transfer of microwave radiation in sliding-mode plasma waveguides produced by ultraviolet laser in atmospheric air.

    Science.gov (United States)

    Zvorykin, Vladimir D; Ionin, Andrei A; Levchenko, Alexei O; Seleznev, Leonid V; Sinitsyn, Dmitrii V; Smetanin, Igor' V; Ustinovskii, Nikolai N; Shutov, Alexei V

    2014-11-01

    Experiments have been performed at hybrid Ti:sapphire/KrF laser facility GARPUN-MTW to develop a novel technique to create a hollow-core sliding-mode plasma-filament waveguide for directed transfer of microwave radiation. Efficient multiphoton air ionization was produced by a train of picosecond 1-TW UV pulses at 248 nm wavelength, or by amplitude-modulated 100 ns pulse combining a short-pulse train with a free-running 1-GW pulse, which detached electrons off O2- ions. Multiple filamentation of UV laser radiation in air was observed, and filamentation theory based on resonance-enhanced ionization was developed to explain the experimental results. PMID:25402935

  5. Linearity of the air kerma values in relation to exposure times in a dental X radiation system

    International Nuclear Information System (INIS)

    The objective of this study was the evaluation of a dental X radiation system intensity variation studying the linearity of the air kerma rate in relation to the exposure time. This study was performed in a Dabi Atlante dental X radiation system. For the exposure time measurements the cone spacer was positioned perpendicular to the detector and the time was varied from 0 to 1.5 s. The air kerma measurements were made in the same conditions for FDD=20.0 cm and 27.5 cm. After that, the obtained values were plotted and a linear adjust was done for each set of measurements. The results showed that the maximum variation obtained was 7% for the third group of measurements for the exposure time of 1.5 s. This variation is less than the recommended limit of 20% published by the Brazilian Health Ministry Regulation 453. (author)

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

    Science.gov (United States)

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

  7. Modeling hourly diffuse solar-radiation in the city of Sao Paulo using a neural-network technique

    International Nuclear Information System (INIS)

    In this work, a perceptron neural-network technique is applied to estimate hourly values of the diffuse solar-radiation at the surface in Sao Paulo City, Brazil, using as input the global solar-radiation and other meteorological parameters measured from 1998 to 2001. The neural-network verification was performed using the hourly measurements of diffuse solar-radiation obtained during the year 2002. The neural network was developed based on both feature determination and pattern selection techniques. It was found that the inclusion of the atmospheric long-wave radiation as input improves the neural-network performance. On the other hand traditional meteorological parameters, like air temperature and atmospheric pressure, are not as important as long-wave radiation which acts as a surrogate for cloud-cover information on the regional scale. An objective evaluation has shown that the diffuse solar-radiation is better reproduced by neural network synthetic series than by a correlation model

  8. Ontologies for the Integration of Air Quality Models and 3D City Models

    CERN Document Server

    Métral, Claudine; Karatzas, Kostas

    2012-01-01

    The holistic approach to sustainable urban planning implies using different models in an integrated way that is capable of simulating the urban system. As the interconnection of such models is not a trivial task, one of the key elements that may be applied is the description of the urban geometric properties in an "interoperable" way. Focusing on air quality as one of the most pronounced urban problems, the geometric aspects of a city may be described by objects such as those defined in CityGML, so that an appropriate air quality model can be applied for estimating the quality of the urban air on the basis of atmospheric flow and chemistry equations. In this paper we first present theoretical background and motivations for the interconnection of 3D city models and other models related to sustainable development and urban planning. Then we present a practical experiment based on the interconnection of CityGML with an air quality model. Our approach is based on the creation of an ontology of air quality models ...

  9. PDF-Based Simulations of Nonpremixed Turbulent Jet Flames With Advanced Radiation Models

    Science.gov (United States)

    Pal, G.; Modest, M. F.; Gupta, A.; Haworth, D. C.

    2010-11-01

    Transported probability density function (PDF) methods have been adopted as the basis for simulating turbulent reacting flows in both Reynolds-averaged and spatially filtered (large-eddy simulation) contexts. Skeletal gas-phase chemical mechanisms have been implemented for oxidation and pollutant formation in hydrocarbon-air flames, and detailed soot models have been implemented using a method-of-moments for soot aerosol dynamics. Photon Monte Carlo and high-order spherical harmonics radiative transfer equation (RTE) solvers have been coupled with the PDF method to deal with participating-medium radiation and turbulence/radiation interactions. Line-by-line and advanced k-distribution methods have been developed for spectral radiation properties. The result is a comprehensive framework for simulating luminous and nonluminous turbulent flames that accurately captures complex turbulence/chemistry/soot/radiation interactions. Quantitative comparisons with experimental measurements have been made. Systematic parametric studies have been performed to explore the relative importance of the choice of RTE solver versus the spectral radiation model.

  10. The impact of air pollutant and methane emission controls on tropospheric ozone and radiative forcing: CTM calculations for the period 1990–2030

    Directory of Open Access Journals (Sweden)

    F. Raes

    2004-12-01

    Full Text Available To explore the relationship between tropospheric ozone and radiative forcing with changing emissions, we compiled two sets of global scenarios for the emissions of the ozone precursors methane (CH4, carbon monoxide (CO, non-methane volatile organic compounds (NMVOC and nitrogen oxides (NOx up to the year 2030 and implemented them in two global Chemistry Transport Models. The "Current Legislation" (CLE scenario reflects the current perspectives of individual countries on future economic development and takes the anticipated effects of presently decided emission control legislation in the individual countries into account. In addition, we developed a "Maximum technically Feasible Reduction" (MFR scenario that outlines the scope for emission reductions offered by full implementation of the presently available emission control technologies, while maintaining the projected levels of anthropogenic activities. Whereas the resulting projections of methane emissions lie within the range suggested by other greenhouse gas projections, the recent pollution control legislation of many Asian countries, requiring introduction of catalytic converters for vehicles, leads to significantly lower growth in emissions of the air pollutants NOx, NMVOC and CO than was suggested by the widely used IPCC (Intergovernmental Panel on Climate Change SRES (Special Report on Emission Scenarios scenarios (Nakicenovic et al., 2000. With the TM3 and STOCHEM models we performed several long-term integrations (1990–2030 to assess global, hemispheric and regional changes in CH4, CO, hydroxyl radicals, ozone and the radiative climate forcings resulting from these two emission scenarios. Both models reproduce realistically the observed trends in background ozone, CO, and CH4 concentrations from 1990 to 2002. For the "current legislation" case, both models indicate an increase of the annual average ozone levels in the Northern hemisphere by 5 ppbv, and up to 15 ppbv over the Indian sub-continent, comparing the 2020s with the 1990s. The corresponding higher ozone and methane burdens in the atmosphere increase radiative forcing by approximately 0.2 Wm?2. Full application of today's emissions control technologies, however, would bring down ozone below the levels experienced in the 1990s and would reduce the current radiative forcing of ozone and methane by approximately 0.1Wm?2. While methane reductions lead to lower ozone burdens and to less radiative forcing, further reductions of the air pollutants NO4 and NMVOC result in lower ozone, but at the same time increase the lifetime of methane. Control of methane emissions appears an efficient option to reduce tropospheric ozone as well as radiative forcing.

  11. 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

  12. Radiation fields, dosimetry, biokinetics and biophysical models for cancer induction by ionising radiation 1996-1999. Executive summary

    International Nuclear Information System (INIS)

    The Association Contract covers a range of research domains that are important to the Radiation Protection Research Action, especially in the areas 'Evaluation of Radiation Risks' and 'Understanding Radiation Mechanisms and Epidemiology'. Three research projects concentrate on radiation dosimetry research and two projects on the modelling of radiation carcinogenesis. The following list gives an overview on the topics and responsible scientific project leaders of the Association Contract: Study of radiation fields and dosimetry at aviation altitudes. Biokinetics and dosimetry of incorporated radionuclides. Dose reconstruction. Biophysical models for the induction of cancer by radiation. Experimental data for the induction of cancer by radiation of different qualities. (orig.)

  13. A modeling analysis of a heavy air pollution episode occurred in Beijing

    OpenAIRE

    An, X.; Zhu, T; Wang, Z.; Li, C; WANG, Y.

    2006-01-01

    The concentrations of fine particulate matter (PM) and ozone in Beijing often exceed healthful levels in recent years, therefore China is to taking steps to improve Beijing's air quality for the 2008 Olympic Games. In this paper, the Models-3 Community Multiscale Air Quality (CMAQ) Modeling System was used to investigate a heavy air pollution episode in Beijing during 3–7 April 2005 to obtain the basic information of how heavy air pollution formed and the contributions of local...

  14. 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.

  15. Econometric model for age- and population-dependent radiation exposures

    International Nuclear Information System (INIS)

    The economic impact associated with ionizing radiation exposures in a given human population depends on numerous factors including the individual's mean economic status as a function age, the age distribution of the population, the future life expectancy at each age, and the latency period for the occurrence of radiation-induced health effects. A simple mathematical model has been developed that provides an analytical methodology for estimating the societal econometrics associated with radiation effects are to be assessed and compared for economic evaluation

  16. 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

  17. Trapped Radiation Model Uncertainties: Model-Data and Model-Model Comparisons

    Science.gov (United States)

    Armstrong, T. W.; Colborn, B. L.

    2000-01-01

    The standard AP8 and AE8 models for predicting trapped proton and electron environments have been compared with several sets of flight data to evaluate model uncertainties. Model comparisons are made with flux and dose measurements made on various U.S. low-Earth orbit satellites (APEX, CRRES, DMSP, LDEF, NOAA) and Space Shuttle flights, on Russian satellites (Photon-8, Cosmos-1887, Cosmos-2044), and on the Russian Mir Space Station. This report gives the details of the model-data comparisons-summary results in terms of empirical model uncertainty factors that can be applied for spacecraft design applications are given in a combination report. The results of model-model comparisons are also presented from standard AP8 and AE8 model predictions compared with the European Space Agency versions of AP8 and AE8 and with Russian-trapped radiation models.

  18. A radiation damage repair model for normal tissues.

    OpenAIRE

    Partridge, M.

    2008-01-01

    A cellular Monte Carlo model describing radiation damage and repair in normal epithelial tissues is presented. The deliberately simplified model includes cell cycling, cell motility and radiation damage response (cell cycle arrest and cell death) only. Results demonstrate that the model produces a stable equilibrium system for mean cell cycle times in the range 24-96 h. Simulated irradiation of these stable equilibrium systems produced a range of responses that are shown to be consistent with...

  19. Simplified models of electromagnetic and gravitational radiation damping

    OpenAIRE

    Kunze, Markus; Rendall, Alan D.

    2001-01-01

    In previous work the authors analysed the global properties of an approximate model of radiation damping for charged particles. This work is put into context and related to the original motivation of understanding approximations used in the study of gravitational radiation damping. It is examined to what extent the results obtained previously depend on the particular model chosen. Comparisons are made with other models for gravitational and electromagnetic fields. The relati...

  20. Modelling relationships between lichen bioindicators, air quality and climate on a national scale: Results from the UK OPAL air survey

    International Nuclear Information System (INIS)

    Air pollution has many negative effects on the natural environment, from changes in plant growth patterns to loss of ecosystem function. This study uses citizen science to investigate national-scale patterns in the distribution and abundance of selected lichen species on tree trunks and branches, and to relate these to air pollution and climate. Volunteers collected data for nine lichen indicators on 19,334 deciduous trees. Submitted data provided information on species-level patterns, and were used to derive composite lichen indices. Multiple linear regression and ANCOVA were used to model the relationships between lichen response variables on Quercus spp. and pollution, climate and location. The study demonstrated significant relationships between patterns in indicator lichens and levels of N- and S-containing pollutants on trunks and twigs. The derived lichen indices show great potential as a tool to provide information on local, site-specific levels of air quality. -- Highlights: •Data on presence and abundance of selected lichens were collected by members of the public. •Indicator species and indices were modelled against air pollution and climate data. •Lichens and indices show significant relationships with nitrogenous air pollution. •Lichen indices are useful tools for providing information on local air quality. -- Data on selected lichen taxa collected by members of the public in England is used to show the relationship of indicator taxa and pollution indices to air pollution and climate data

  1. A comparative evaluation of gray and non-gray radiation modeling strategies in oxy-coal combustion simulations

    International Nuclear Information System (INIS)

    Computational fluid dynamic simulations of oxy-coal combustion are demonstrated in a lab-scale furnace and full-scale boiler employing gray and non-gray formulations of recently proposed radiative property models for the gas-phase. The investigated scenarios included: air-firing, oxy-firing with dry and wet flue-gas recycle (FGR). The study confirms that the temperature and wall radiative flux profiles encountered during air firing can be replicated in both dry and wet FGR scenarios through an appropriate selection of (CO2 + H2O)/O2 molar ratios in the oxidizer stream. The computed temperature profiles were in reasonable agreement with the experimental measurements. In the lab-scale furnace, lower flame temperatures and smaller path lengths minimized the differences between the gray and non-gray model predictions. Within the full-scale boiler, large volume pockets were present where the radiation was dominated by the gas-phase. This combined with higher peak flame temperatures and longer path lengths resulted in: a 10% variation between the gray and non-gray radiative fluxes and a 50 K difference in the predicted average outlet gas temperatures. -- Highlights: ? Oxy-coal combustion simulations with dry and wet flue gas recycle was studied. ? Temperatures were more sensitive to devolatilization models than radiation models. ? Gray and non-gray modeling differences were amplified in larger geometries. ? Higher flame temperatures also contributed to model differences. ? Predictions from two recently proposed non-gray WSGG models were similar

  2. Longwave radiative transfer in the atmosphere: Model development and applications

    Science.gov (United States)

    Delamere, Jennifer Simmons

    A FLexible Radiative Transfer Tool (FLRTT) has been developed to facilitate the construction of longwave, correlated k-distribution, radiative transfer models. The correlated k-distribution method is a technique which accelerates calculations of radiances, fluxes, and cooling rates in inhomogeneous atmospheres; therefore, correlated k-distribution models are appropriate for simulations of satellite radiances and inclusion into general circulation models. FLRTT was used to build two new rapid radiative transfer models, RRTM_HIRS and RRTM_v3.0, which maintain accuracy comparable to the line-by-line radiative transfer model LBLRTM. Iacono et al. [2003] evaluated upper tropospheric water vapor (UTWV) simulated by the National Center for Atmospheric Research Community Climate Model, CCM3, by comparing modeled, clear-sky brightness-temperatures to those observed from space by the High-resolution Radiation Sounder (HIRS). CCM3 was modified to utilize the rapid radiative transfer model RRTM and the separate satellite-radiance module, RRTM_HIRS, which calculates brightness temperatures in two HIRS channels. By incorporating these accurate radiative transfer models into CCM3, the longwave radiative transfer calculations have been removed as a significant source of error in the simulations. An important result of this study is that CCM3 exhibits moist and dry discrepancies in UTWV of 50% in particular climatic regions, which may be attributed to errors in the CCM3 dynamical schemes. RRTM_v3.0, an update of RRTM, is a rapid longwave radiative transfer appropriate for use in general circulation models. Fluxes calculated by RRTM_v3.0 agree with those computed by the LBLRTM to within 1.0 W/m2 at all levels, and the computed cooling rates agree to within 0.1 K/day and 0.3 K/day in the troposphere and stratosphere, respectively. This thesis also assessed and improved the modeling of clear-sky, longwave radiative fluxes at the Atmospheric Radiation Measurement Program North Slope of Alaska site by simultaneously addressing the specification of the atmosphere, radiometric measurements, and radiative transfer modeling. Consistent with findings from other field sites, the specification of the atmospheric water vapor is found to be a large source of uncertainty in modeled radiances and fluxes. Improvements in the specification of carbon dioxide optical depths within LBLRTM resulted, in part, from this analysis.

  3. Study of hot air generator with quasi-uniform temperature using concentrated solar radiation: Influence of the shape parameters

    Energy Technology Data Exchange (ETDEWEB)

    Ould Mohamed Mahmoud, Ahmedou [Faculte des Sciences et Techniques de Nouakchott, Departement de Physique, BP 5026, Nouakchott (Mauritania); Zinoubi, Jamil [Institut preparatoire aux etudes d' ingenieurs de Nabeul, Merazka, Nabeul (Tunisia); Ben Maad, Rejeb [Faculte des Sciences de Tunis, Laboratoire d' Energetique et des Transferts Thermique et Massique, El Manar, Tunis (Tunisia). Departement de Physique

    2007-02-15

    The non-uniformity of the air temperatures and the slow flow rate at the plane collector exit constitute the main cause of the limitations of the solar drying systems. In order to obtain an uniform and a variable flow rate for different uses, a hot air generator using concentrated solar radiation is proposed. To improve the thermal efficiency of the generator, a study of the influence of different shape parameters is realized. The generator is simulated in the laboratory while investigating the flow induced by a circular disc heated uniformly by Joule effect at constant temperature. This disc is placed at the entrance of an open ended vertical cylinder of a larger diameter. Thermal radiation emitted by the hot disc heats the cylinder wall. The heating of the fluid at the cylinder-inlet generates a thermosiphon flow around the one created by the hot disc. The comparison of the velocity and the temperature profiles of the resulting flow permits to determine the influence of the cylinder height, the vertical source-cylinder spacing and the radius ratio, on the resulting flow at the system exit. Thus, a judicious choice of the shape parameters entails an improvement of the flow rate as well as the thermal flux absorbed by the air and a good homogenization of the air temperature at the generator exit. (author)

  4. 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.

  5. The Influence of Tropical Air-Sea Interaction on the Climate Impact of Aerosols: A Hierarchical Modeling Approach

    Science.gov (United States)

    Hsieh, W. C.; Saravanan, R.; Chang, P.; Mahajan, S.

    2014-12-01

    In this study, we use a hierarchical modeling approach to investigate the influence of tropical air-sea feedbacks on climate impacts of aerosols in the Community Earth System Model (CESM). We construct four different models by coupling the atmospheric component of CESM, the Community Atmospheric Model (CAM), to four different ocean models: (i) the Data Ocean Model (DOM; prescribed SST), (i) Slab Ocean Model (SOM; thermodynamic coupling), (iii) Reduced Gravity Ocean Model (RGOM; dynamic coupling), and (iv) the Parallel Ocean Program (POP; full ocean model). These four models represent progressively increasing degree of coupling between the atmosphere and the ocean. The RGOM model, in particular, is tuned to produce a good simulation of ENSO and the associated tropical air-sea interaction, without being impacted by the climate drifts exhibited by fully-coupled GCMs. For each method of coupling, a pair of numerical experiments, including present day (year 2000) and preindustrial (year 1850) sulfate aerosol loading, were carried out. Our results indicate that the inclusion of air-sea interaction has large impacts on the spatial structure of the climate response induced by aerosols. In response to sulfate aerosol forcing, ITCZ shifts southwards as a result of the anomalous clockwise MMC change which transports moisture southwardly across the Equator. We present analyses of the regional response to sulfate aerosol forcing in the equatorial Pacific as well as the zonally-averaged response. The decomposition of the change in the net surface energy flux shows the most dominant terms are net shortwave radiative flux at the surface and latent heat flux. Further analyses show all ocean model simulations simulate a positive change of northward atmospheric energy transport across the Equator in response to the perturbed radiative sulfate forcing. This positive northward atmospheric energy transport change plays a role in compensating partially cooling caused by sulfate aerosols.

  6. A model for the calculation of the radiation dose from natural radionuclides in The Netherlands

    International Nuclear Information System (INIS)

    A model has been developed to calculate the radiation dose incurred from natural radioactivity indoors and outdoors, expressed in effective dose equivalence/year. The model is applied on a three rooms dwelling characterized by interconnecting air flows and on a dwelling with crawlspace. In this model the distinct parameters are variable in order to allow the investigation of the relative influence. The calculated effective dose equivalent for an adult in the dwelling was calculated to be about 1.7 mSv/year, composed of 15% from cosmic radiation, 35% from terrestrial radioactivity, 20% from radioactivity in the body and 30% from natural radionuclides in building materials. The calculations show an enhancement of about a factor of two in radon concentration in air in a room which is ventilated by air from an adjacent room. It is also shown that the attachment rate of radon products to aerosols and the plate-out effect are relatively important parameters influencing the magnitude of the dose rate. (Auth.)

  7. The NIAID Radiation Countermeasures Program Business Model

    OpenAIRE

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

    2010-01-01

    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 prov...

  8. Atmospheric Boundary Layer Modeling for Combined Meteorology and Air Quality Systems

    Science.gov (United States)

    Atmospheric Eulerian grid models for mesoscale and larger applications require sub-grid models for turbulent vertical exchange processes, particularly within the Planetary Boundary Layer (PSL). In combined meteorology and air quality modeling systems consistent PSL modeling of wi...

  9. Improvement of local air coolers model in ISAAC

    International Nuclear Information System (INIS)

    The purpose of this paper is to assess a new local air coolers (LACs) model in ISAAC 2.0, as ISAAC 1.0 could model LAC only at two locations. In the new model, LACs 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 LACs in one of the fueling machine room and in the steam generator room, respectively, and the other with 3 LACs at both fueling machine room and 6 LACs 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 results, the new LACs 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

  10. Use of heavy ions to model radiation damage of metals

    International Nuclear Information System (INIS)

    The methods for modeling radiation damage of metals using heavy ions are reviewed and the results obtained are analyzed. It is shown that irradiation of metals with heavy ion can simulate neutron exposure with the equivalent dose with adequate accuracy and permits a detailed analysis of radiation damage of metals

  11. 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 200°C 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 makè clusters (atomic clusters) where each atom hás 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 80°K and 110°K. 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 160°K. 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 200“C and above. C2 molecules then recombine with vacancies or escape to surfaces, causing energy release. The striking energy release around 200°C 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 1000°C. (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 1000°C. (author)

  12. Combined Cloud-Microwave Radiative Transfer Modeling of Stratiform Rainfall.

    Science.gov (United States)

    Bauer, Peter; Khain, A.; Pokrovsky, A.; Meneghini, R.; Kummerow, C.; Marzano, F.; Poiares Baptista, J. P. V.

    2000-04-01

    The simulation of explicit particle spectra during cloud evolution by a two-dimensional spectral cloud model was used to investigate the response of microwave radiative transfer to particle spectra development with special focus on the radiative effects of melting particles below the freezing level. For this purpose, 1) a particle-melting model was implemented with increased vertical resolution; 2) several models of the dielectric permittivity for melting particles were compared; 3) the dependence on size-density distributions was evaluated; and 4) the influence on the results by the replacement of explicit by parameterized particle spectra was tested.Radiative transfer simulations over ocean background at frequencies between 10.7 and 85.5 GHz showed a considerable increase in brightness temperatures (TB) once melting particles were included. The amounts were strongly dependent on the implemented permittivity model, the number concentrations of large frozen particles right above the freezing level, and the local cloud conditions. Assuming a random mixture of air, ice, and meltwater in the particle, TBs increased by up to 30 K (at 37.0 GHz) in the stratiform cloud portion for nadir view. If the meltwater was taken to reside at the particle boundaries, unrealistic TB changes were produced at all frequencies. This led to the conclusion that for large tenuous snowflakes the random-mixture model seems most appropriate, while for small and dense particles a nonuniform water distribution may be realistic. The net melting effect on simulated TBs, however, depended strongly on attenuation by supercooled liquid water above the freezing level, which generally suppressed the signal at 85.5 GHz. Over land background, changes in TB due to melting particles remained below 8 K, which would be difficult to identify compared to variations in surface emission and cloud profile heterogeneity.Replacement of the explicit particle spectra for rain, snow, and graupel by parameterized spectra (here, in exponential form with a fixed intercept) produced reductions of the melting signature by up to 40% over ocean. It was found that exponential size distribution formulas tended to underestimate number concentrations of large particles and overestimated those of small particles at those cloud levels where sufficient particle sedimentation leads to collection, aggregation, and evaporation, respectively. Consequently, the strongest differences between explicit and parameterized spectra occurred right above the freezing level for snow and graupel, and close to the surface for rain. Radiometrically, this resulted in an underestimation of scattering above the freezing level and an underestimation of emission by melting particles below the freezing level as well as by rain toward the surface. In the stratiform region, the net effect was a reduction of the melting signature; however, TB's were still up to 15 K higher than from the no-melting case for the random-mixture permittivity model.

  13. A Linear Regression Model for Global Solar Radiation on Horizontal Surfaces at Warri, Nigeria

    Directory of Open Access Journals (Sweden)

    Michael S. Okundamiya

    2013-10-01

    Full Text Available The growing anxiety on the negative effects of fossil fuels on the environment and the global emission reduction targets call for a more extensive use of renewable energy alternatives. Efficient solar energy utilization is an essential solution to the high atmospheric pollution caused by fossil fuel combustion. Global solar radiation (GSR data, which are useful for the design and evaluation of solar energy conversion system, are not measured at the forty-five meteorological stations in Nigeria. The dearth of the measured solar radiation data calls for accurate estimation. This study proposed a temperature-based linear regression, for predicting the monthly average daily GSR on horizontal surfaces, at Warri (latitude 5.020N and longitude 7.880E an oil city located in the south-south geopolitical zone, in Nigeria. The proposed model is analyzed based on five statistical indicators (coefficient of correlation, coefficient of determination, mean bias error, root mean square error, and t-statistic, and compared with the existing sunshine-based model for the same study. The results indicate that the proposed temperature-based linear regression model could replace the existing sunshine-based model for generating global solar radiation data. Keywords: air temperature; empirical model; global solar radiation; regression analysis; renewable energy; Warri

  14. Modeling The Dynamics Of Outer Radiation Belt Electrons

    CERN Document Server

    Naehr, S M

    2000-01-01

    A computer model has been built to simulate the dynamic evolution of relativistic electrons in the outer radiation belt. The model calculates changes in electron flux due to three mechanisms: (1) fully-adiabatic response of electrons to variations in the magnetic field, (2) time-dependent radial diffusion, parameterized by overall magnetospheric activity, and (3) penetration of new particles into the model via a time-dependent outer boundary condition. Data from Los Alamos geosynchronous satellites, the CRRESELE statistical electron flux model, the Kp index, and the Toffoletto-Hill-Ding magnetic field model are all used to provide realistic, time-dependent inputs to the model. To evaluate the model, a simulation of the radiation belts during the November 3–12, 1993 magnetic storm was generated. Comparison of results to Global Positioning System (GPS) radiation dosimeter data indicates that the model can accurately predict storm-time flux variations for electrons with energies less than 600 keV. Mode...

  15. Atmospheric dispersion models help to improve air quality; Los modelos de dispersion atmosferica ayudan a mejorar la calidad del aire

    Energy Technology Data Exchange (ETDEWEB)

    Martin, F.

    2013-07-01

    One of the main challenges of the atmospheric sciences is to reproduce as well as possible the phenomena and processes of pollutants in the atmosphere. To do it, mathematical models based in this case on fluid dynamics and mass and energy conservation equations, equations that govern the atmospheric chemistry, etc., adapted to the spatial scales to be simulated, are developed. The dispersion models simulate the processes of transport, dispersion, chemical transformation and elimination by deposition that air pollutants undergo once they are emitted. Atmospheric dispersion models with their multiple applications have become essential tools for the air quality management. (Author)

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

    Directory of Open Access Journals (Sweden)

    K. Vijayaraghavan

    2010-09-01

    Full Text Available 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 mercury compounds. The linkage may also be used to obtain meteorological fields such as precipitation and air temperature required by WARMF from the outputs of the meteorology chemistry interface processor (MCIP that processes meteorology simulated by the fifth generation Mesoscale Model (MM5 or the Weather Research and Forecast (WRF model for input to AMSTERDAM. The linkage is tested in the Catawba River basin of North and South Carolina for ammonium, nitrate and sulfate. Modeled air quality and meteorological fields transferred by the linkage can supplement the conventional measurements used to drive WARMF and may be used to help predict the impact of changes in atmospheric emissions on water quality.

  17. Modeling Regional Air Quality Impacts from Indonesian Biomass Burning

    Science.gov (United States)

    Jumbam, L.; Raffuse, S. M.; Wiedinmyer, C.; Larkin, N.

    2012-12-01

    Smoke from thousands of forest-clearing burns in Indonesia cause widespread air quality impacts in cities across southeastern Asia. These fires, which can produce significant smoke due to peat burning, are readily detected by polar orbiting satellites. Widespread smoke can be seen in satellite imagery, and high concentrations of particulate matter are detected by ground based sensors. Here we present results of a pilot modeling study focusing on the September 2011 Indonesian smoke episode. In the study, fire location information was collected from the National Aeronautics and Space Administration's (NASA) Moderate Resolution Imaging Spectroradiometer (MODIS). The BlueSky modeling framework, which links information about fire locations with smoke emissions and meteorological models, was used to pass the fire location information from MODIS through the Fire INventories from NCAR (FINN) methodology to estimate emissions of aerosol and gaseous pollutants from the fires. These emissions were further directed by BlueSky through the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model, which predicted the dispersion and transport of PM2.5 from the fires. The resulting regional PM2.5 concentration maps from BlueSky were compared with satellite imagery and urban ground stations, where available. This work demonstrates the extension of a system developed for producing daily smoke predictions in the United States outside of North America for the first time. We discuss the implications of regional smoke impacts and possibilities for predictive smoke modeling to protect public health in southeastern Asia.

  18. Cloud-Aerosol-Radiation (CAR ensemble modeling system

    Directory of Open Access Journals (Sweden)

    X.-Z. Liang

    2013-04-01

    Full Text Available A Cloud-Aerosol-Radiation (CAR ensemble modeling system has been developed to incorporate the largest choices of alternative parameterizations for cloud properties (cover, water, radius, optics, geometry, aerosol properties (type, profile, optics, radiation transfers (solar, infrared, and their interactions. These schemes form the most comprehensive collection currently available in the literature, including those used by the world leading general circulation models (GCMs. The CAR provides a unique framework to determine (via intercomparison across all schemes, reduce (via optimized ensemble simulations, and attribute specific key factors for (via physical process sensitivity analyses the model discrepancies and uncertainties in representing greenhouse gas, aerosol and cloud radiative forcing effects. This study presents a general description of the CAR system and illustrates its capabilities for climate modeling applications, especially in the context of estimating climate sensitivity and uncertainty range caused by cloud-aerosol-radiation interactions. For demonstration purpose, the evaluation is based on several CAR standalone and coupled climate model experiments, each comparing a limited subset of the full system ensemble with up to 896 members. It is shown that the quantification of radiative forcings and climate impacts strongly depends on the choices of the cloud, aerosol and radiation schemes. The prevailing schemes used in current GCMs are likely insufficient in variety and physically biased in a significant way. There exists large room for improvement by optimally combining radiation transfer with cloud property schemes.

  19. A Numerical Study of Tropical Sea-Air Interactions Using a Cloud Resolving Model Coupled with an Ocean Mixed-Layer Model

    Science.gov (United States)

    Shie, Chung-Lin; Tao, Wei-Kuo; Johnson, Dan; Simpson, Joanne; Li, Xiaofan; Sui, Chung-Hsiung; Einaudi, Franco (Technical Monitor)

    2001-01-01

    Coupling a cloud resolving model (CRM) with an ocean mixed layer (OML) model can provide a powerful tool for better understanding impacts of atmospheric precipitation on sea surface temperature (SST) and salinity. The objective of this study is twofold. First, by using the three dimensional (3-D) CRM-simulated (the Goddard Cumulus Ensemble model, GCE) diabatic source terms, radiation (longwave and shortwave), surface fluxes (sensible and latent heat, and wind stress), and precipitation as input for the OML model, the respective impact of individual component on upper ocean heat and salt budgets are investigated. Secondly, a two-way air-sea interaction between tropical atmospheric climates (involving atmospheric radiative-convective processes) and upper ocean boundary layer is also examined using a coupled two dimensional (2-D) GCE and OML model. Results presented here, however, only involve the first aspect. Complete results will be presented at the conference.

  20. Radiation passbook and training model for outside workers in Spain

    International Nuclear Information System (INIS)

    European Directive 90/641/Euratom established the general framework for operational protection of outside workers exposed to the risk of ionising radiation during their activities in controlled areas. In Spain this Directive has been transposed through Royal Decree 413/1997, which established specific responsibilities regarding Radiation Passbook and the training in radiation protection of outside workers. The Spanish radiation passbook was introduced in 1990 and since this time, Nuclear Safety Council (CSN), as the regulatory authority has required that all outside workers entering controlled areas should have radiation passbooks. Recently, CSN has implemented improvements in the Spanish radiation passbooks taking into account the previous experience and the Directive 96/29/Euratom. With regard to training in radiation protection of outside workers, in 1998 the CSN and the Association of the electricity utilities (UNESA) initiated joint efforts to define a new radiation protection training model for Spanish outside workers. This model should involve both the outside undertaking and the nuclear power plants. Several options already implemented in other European countries were studied and as result a model based on the following criteria was developed: - An initial training course which is responsibility of the outside undertaking. - A specific course which will be responsibility of the operators of the controlled area in which outside workers perform the activities. ( outside workers perform the activities. (authors)

  1. Dynamic stochastic optimization models for air traffic flow management

    Science.gov (United States)

    Mukherjee, Avijit

    This dissertation presents dynamic stochastic optimization models for Air Traffic Flow Management (ATFM) that enables decisions to adapt to new information on evolving capacities of National Airspace System (NAS) resources. Uncertainty is represented by a set of capacity scenarios, each depicting a particular time-varying capacity profile of NAS resources. We use the concept of a scenario tree in which multiple scenarios are possible initially. Scenarios are eliminated as possibilities in a succession of branching points, until the specific scenario that will be realized on a particular day is known. Thus the scenario tree branching provides updated information on evolving scenarios, and allows ATFM decisions to be re-addressed and revised. First, we propose a dynamic stochastic model for a single airport ground holding problem (SAGHP) that can be used for planning Ground Delay Programs (GDPs) when there is uncertainty about future airport arrival capacities. Ground delays of non-departed flights can be revised based on updated information from scenario tree branching. The problem is formulated so that a wide range of objective functions, including non-linear delay cost functions and functions that reflect equity concerns can be optimized. Furthermore, the model improves on existing practice by ensuring efficient use of available capacity without necessarily exempting long-haul flights. Following this, we present a methodology and optimization models that can be used for decentralized decision making by individual airlines in the GDP planning process, using the solutions from the stochastic dynamic SAGHP. Airlines are allowed to perform cancellations, and re-allocate slots to remaining flights by substitutions. We also present an optimization model that can be used by the FAA, after the airlines perform cancellation and substitutions, to re-utilize vacant arrival slots that are created due to cancellations. Finally, we present three stochastic integer programming models for managing inbound air traffic flow of an airport, when there is adverse weather impacting the arrival capacity of the airport along with its arrival fixes. These are the first models, for optimizing ATFM decisions, which address uncertainty of future capacities of multiple NAS resources.

  2. A space radiation shielding model of the Martian radiation environment experiment (MARIE)

    International Nuclear Information System (INIS)

    The 2001 Mars Odyssey spacecraft was launched towards Mars on April 7, 2001. On board the spacecraft is the Martian radiation environment experiment (MARIE), which is designed to measure the background radiation environment due to galactic cosmic rays (GCR) and solar protons in the 20 500 MeV/n energy range. We present an approach for developing a space radiation-shielding model of the spacecraft that includes the MARIE instrument in the current mapping phase orientation. A discussion is presented describing the development and methodology used to construct the shielding model. For a given GCR model environment, using the current MARIE shielding model and the high-energy particle transport codes, dose rate values are compared with MARIE measurements during the early mapping phase in Mars orbit. The results show good agreement between the model calculations and the MARIE measurements as presented for the March 2002 dataset

  3. MODELING OF RADIATING EFFECTS IN CAD OF MICROELECTRONICS ????????????? ???????????? ???????? ? ???? ????????????????

    Directory of Open Access Journals (Sweden)

    Achkasov V. N.

    2012-01-01

    Full Text Available The methods of modeling of radiating effects of microcircuits in microcircuits are submitted. The technique of designing, information and lingware is considered. The methods of an estimation of stability to transitive effects are offered

  4. Modeling of radiation effects in cells and tissues.

    Czech Academy of Sciences Publication Activity Database

    Friedland, W.; Kundrát, Pavel

    1. Amsterdam : Elsevier, 2014 - (Brahme, A.), s. 105-142 ISBN 978-0444536327. - (Reference Module in Biomedical Sciences) Institutional support: RVO:68378271 Keywords : ionizing radiation * iological effects * athematical modeling * echanistic simulations * onte Carlo simulations Subject RIV: BO - Biophysics

  5. The DIRTY Model. I. Monte Carlo Radiative Transfer Through Dust

    CERN Document Server

    Gordon, K D; Witt, A N; Clayton, G C; Gordon, Karl D.; Witt, Adolf N.; Clayton, Geoffrey C.

    2001-01-01

    We present the DIRTY radiative transfer model in this paper and a companion paper. This model computes the polarized radiative transfer of photons from arbitrary distributions of stars through arbitrary distributions of dust using Monte Carlo techniques. The dust re-emission is done self-consistently with the dust absorption and scattering and includes all three important emission paths: equilibrium thermal emission, non-equilibrium thermal emission, and the aromatic features emission. The algorithm used for the radiative transfer allows for the efficient computation of the appearance of a model system as seen from any viewing direction. We present a simple method for computing an upper limit on the output quantity uncertainties for Monte Carlo radiative transfer models which use the weighted photon approach.

  6. [Treatment of cloud radiative effects in general circulation models

    International Nuclear Information System (INIS)

    This is a renewal proposal for an on-going project of the Department of Energy (DOE)/Atmospheric Radiation Measurement (ARM) Program. The objective of the ARM Program is to improve the treatment of radiation-cloud in GCMs so that reliable predictions of the timing and magnitude of greenhouse gas-induced global warming and regional responses can be made. The ARM Program supports two research areas: (I) The modeling and analysis of data related to the parameterization of clouds and radiation in general circulation models (GCMs); and (II) the development of advanced instrumentation for both mapping the three-dimensional structure of the atmosphere and high accuracy/precision radiometric observations. The present project conducts research in area (I) and focuses on GCM treatment of cloud life cycle, optical properties, and vertical overlapping. The project has two tasks: (1) Development and Refinement of GCM Radiation-Cloud Treatment Using ARM Data; and (2) Validation of GCM Radiation-Cloud Treatment

  7. INITIAL VERIFICATION OF THE ENVIRONMENTAL PROTECTION AGENCY (EPA) INDOOR AIR QUALITY MODEL EXPOSURE VERSION 2

    Science.gov (United States)

    The paper describes experiments to verify an indoor air quality (IAQ) model, EXPOSURE, that includes the interactions of sources, sinks, and air movement between rooms and between buildings and the outdoors. ources may be located in rooms, in the heating, ventilation, and air-con...

  8. Assessing Air-Sea Interaction in the Evolving NASA GEOS Model

    Science.gov (United States)

    Clayson, Carol Anne; Roberts, J. Brent

    2015-01-01

    In order to understand how the climate responds to variations in forcing, one necessary component is to understand the full distribution of variability of exchanges of heat and moisture between the atmosphere and ocean. Surface heat and moisture fluxes are critical to the generation and decay of many coupled air-sea phenomena. These mechanisms operate across a number of scales and contain contributions from interactions between the anomalous (i.e. non-mean), often extreme-valued, flux components. Satellite-derived estimates of the surface turbulent and radiative heat fluxes provide an opportunity to assess results from modeling systems. Evaluation of only time mean and variability statistics, however only provides limited traceability to processes controlling what are often regime-dependent errors. This work will present an approach to evaluate the representation of the turbulent fluxes at the air-sea interface in the current and evolving Goddard Earth Observing System (GEOS) model. A temperature and moisture vertical profile-based clustering technique is used to identify robust weather regimes, and subsequently intercompare the turbulent fluxes and near-surface parameters within these regimes in both satellite estimates and GEOS-driven data sets. Both model reanalysis (MERRA) and seasonal-to-interannual coupled GEOS model simulations will be evaluated. Particular emphasis is placed on understanding the distribution of the fluxes including extremes, and the representation of near-surface forcing variables directly related to their estimation. Results from these analyses will help identify the existence and source of regime-dependent biases in the GEOS model ocean surface turbulent fluxes. The use of the temperature and moisture profiles for weather-state clustering will be highlighted for its potential broad application to 3-D output typical of model simulations.

  9. Assessing air-sea interaction in the evolving NASA GEOS model

    Science.gov (United States)

    Clayson, C. A.; Roberts, J. B.

    2014-12-01

    In order to understand how the climate responds to variations in forcing, one necessary component is to understand the full distribution of variability of exchanges of heat and moisture between the atmosphere and ocean. Surface heat and moisture fluxes are critical to the generation and decay of many coupled air-sea phenomena. These mechanisms operate across a number of scales and contain contributions from interactions between the anomalous (i.e. non-mean), often extreme-valued, flux components. Satellite-derived estimates of the surface turbulent and radiative heat fluxes provide an opportunity to assess results from modeling systems. Evaluation of only time mean and variability statistics, however only provides limited traceability to processes controlling what are often regime-dependent errors. This work will present an approach to evaluate the representation of the turbulent fluxes at the air-sea interface in the current and evolving Goddard Earth Observing System (GEOS) model. A temperature and moisture vertical profile-based clustering technique is used to identify robust weather regimes, and subsequently intercompare the turbulent fluxes and near-surface parameters within these regimes in both satellite estimates and GEOS-driven data sets. Both model reanalysis (MERRA) and seasonal-to-interannual coupled GEOS model simulations will be evaluated. Particular emphasis is placed on understanding the distribution of the fluxes including extremes, and the representation of near-surface forcing variables directly related to their estimation. Results from these analyses will help identify the existence and source of regime-dependent biases in the GEOS model ocean surface turbulent fluxes. The use of the temperature and moisture profiles for weather-state clustering will be highlighted for its potential broad application to 3-D output typical of model simulations.

  10. Radiative lepton flavour violation in SUSY GUT models

    International Nuclear Information System (INIS)

    The small flavour mixing in the quark sector can be generated radiatively from SUSY-breaking terms in the MSSM. However,it seems difficult to generate the large neutrino mixing radiatively. Embedding the MSSM into a left-right symmetric model, which realizes the seesaw formula for the light neutrino masses, we constrain the trilinear terms in the SUSY breaking sector. In this class of models we get an appealing correlation between LR breaking scale and soft SUSY breaking parameters.

  11. Modelling air pollution abatement in deep street canyons by means of air scrubbers

    CERN Document Server

    De Giovanni, Marina; 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 APA technology depletes gaseous and particulate air pollutants by a portable and low-consuming scrubbing system, that mimics the processes of wet and dry deposition. We estimate the potential pollutant abatement efficacy of a single absorber by Computational Fluid Dynamics (CFD) method. The presence of the scrubber effectively creates an additional sink at the bottom of the canyon, accelerating its cleaning process by up to 70%, when an almost perfect scrubber (90% efficiency) is simulated. The efficacy of absorber is not...

  12. Radiation Heat Transfer Effect on Thermal Sizing of Air-Cooling Heat Exchanger of Emergency Cooldown Tank

    International Nuclear Information System (INIS)

    An attempt has begun to extend the life time of emergency cooldown tank (ECT) by Korea Atomic Energy Research Institute (KAERI) researchers. Moon et al. recently reported a basic concept upon how to keep the ECT in operation beyond 72 hours after an accident occurs without any active corrective actions for the postulated design basis accidents. When the SMART (System-integrated Modular Advanced Reac-Tor) received its Standard Design Approval (SDA) for the first time in the world, hybrid safety systems are applied. However, the passive safety systems of SMART are being enforced in response to the public concern for much safer reactors since the Fukushima accident occurred. The ECT is a major component of a passive residual heat removal system (PRHRS), which is one of the most important systems to enhance the safety of SMART. It is being developed in a SMART safety enhancement project to contain enough cooling water to remove a sensible heat and a decay heat from reactor core for 72 hours since an accident occurs. Moon et al. offered to install another heat exchanger above the ECT and to recirculate an evaporated steam into water, which enables the ECT to be in operation, theoretically, indefinitely. An investigation was made to determine how long and how many tubes were required to meet the purpose of the study. In their calculation, however, a radiation heat transfer effect was neglected. The present study is to consider the radiation heat transfer for the design of air-cooling heat exchanger. Radiation heat transfer is normally ignored in many situations, but this is not the case for the present study. Kim et al. conducted thermal sizing of scaled-down ECT heat exchanger, which will be used to validate experimentally the basic concept of the present study. Their calculation is also examined to see if a radiation heat transfer effect was taken into consideration. The thermal sizing of an air-cooling heat exchanger was conducted including radiation heat transfer. Investigations were made using several heat transfer correlations for natural convection of the vertical tubes and also the radiation heat transfer term. It is revealed that the radiation should not be neglected for the present air-cooling heat exchanger. This work will contribute to evaluate the feasibility of the basic concept upon an extension of the cooling period of ECT to longer than 72 hours, which will enhance the passive safety systems of SMART

  13. Radiation Heat Transfer Effect on Thermal Sizing of Air-Cooling Heat Exchanger of Emergency Cooldown Tank

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Joo Hyung; Kim, Young In; Kim, Keung Koo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Myoung Jun; Lee, Hee Joon [School of Mechanical Eng., Kookmin University, Seoul (Korea, Republic of)

    2014-10-15

    An attempt has begun to extend the life time of emergency cooldown tank (ECT) by Korea Atomic Energy Research Institute (KAERI) researchers. Moon et al. recently reported a basic concept upon how to keep the ECT in operation beyond 72 hours after an accident occurs without any active corrective actions for the postulated design basis accidents. When the SMART (System-integrated Modular Advanced Reac-Tor) received its Standard Design Approval (SDA) for the first time in the world, hybrid safety systems are applied. However, the passive safety systems of SMART are being enforced in response to the public concern for much safer reactors since the Fukushima accident occurred. The ECT is a major component of a passive residual heat removal system (PRHRS), which is one of the most important systems to enhance the safety of SMART. It is being developed in a SMART safety enhancement project to contain enough cooling water to remove a sensible heat and a decay heat from reactor core for 72 hours since an accident occurs. Moon et al. offered to install another heat exchanger above the ECT and to recirculate an evaporated steam into water, which enables the ECT to be in operation, theoretically, indefinitely. An investigation was made to determine how long and how many tubes were required to meet the purpose of the study. In their calculation, however, a radiation heat transfer effect was neglected. The present study is to consider the radiation heat transfer for the design of air-cooling heat exchanger. Radiation heat transfer is normally ignored in many situations, but this is not the case for the present study. Kim et al. conducted thermal sizing of scaled-down ECT heat exchanger, which will be used to validate experimentally the basic concept of the present study. Their calculation is also examined to see if a radiation heat transfer effect was taken into consideration. The thermal sizing of an air-cooling heat exchanger was conducted including radiation heat transfer. Investigations were made using several heat transfer correlations for natural convection of the vertical tubes and also the radiation heat transfer term. It is revealed that the radiation should not be neglected for the present air-cooling heat exchanger. This work will contribute to evaluate the feasibility of the basic concept upon an extension of the cooling period of ECT to longer than 72 hours, which will enhance the passive safety systems of SMART.

  14. A Monte Carlo model of an industrial gauge for radiation protection purposes.

    Science.gov (United States)

    McGurk, R; Turner, J; Deloar, H M; Packer, K

    2008-03-01

    The Mahlo Gravimat densitometers/gauges located at the Feltex carpet factory in Christchurch, New Zealand, contain the radionuclide strontium-90 (Sr-90). Accurate dose/dose rate estimation is always an important concern from a radiation protection point of view. The EGSnrc/BEAMnrc Monte Carlo code was used to create a model of one gauge to determination of the radiation dose distributions and dose rates in air from the Sr-90 source within the gauge. The model was then modified to include a Perspex shield on the surface of the gauge as a possible method of lowering the radiation levels. With this addition, the model predicted an overall reduction in dose rates of 30%. Although no experimental benchmarking was able to be performed due to simplifications in the model and the lack of reliable experimental data, we believe that Monte Carlo methods could be a valuable addition in the design process of any devices, industrial or otherwise, that contain or use radioactive materials. Furthermore, such methods may aide or guide any investigations undertaken as part of radiation protection surveys. PMID:18488963

  15. Computer Model to Estimate Reliability Engineering for Air Conditioning Systems

    International Nuclear Information System (INIS)

    Reliability engineering is used to predict the performance and optimize design and maintenance of air conditioning systems. Air conditioning systems are expose to a number of failures. The failures of an air conditioner such as turn on, loss of air conditioner cooling capacity, reduced air conditioning output temperatures, loss of cool air supply and loss of air flow entirely can be due to a variety of problems with one or more components of an air conditioner or air conditioning system. Forecasting for system failure rates are very important for maintenance. This paper focused on the reliability of the air conditioning systems. Statistical distributions that were commonly applied in reliability settings: the standard (2 parameter) Weibull and Gamma distributions. After distributions parameters had been estimated, reliability estimations and predictions were used for evaluations. To evaluate good operating condition in a building, the reliability of the air conditioning system that supplies conditioned air to the several The company's departments. This air conditioning system is divided into two, namely the main chilled water system and the ten air handling systems that serves the ten departments. In a chilled-water system the air conditioner cools water down to 40-45 degree F (4-7 degree C). The chilled water is distributed throughout the building in a piping system and connected to air condition cooling units wherever needed. Data analysis has been done with support. Data analysis has been done with support a computer aided reliability software, this is due to the Weibull and Gamma distributions indicated that the reliability for the systems equal to 86.012% and 77.7% respectively. A comparison between the two important families of distribution functions, namely, the Weibull and Gamma families was studied. It was found that Weibull method performed for decision making.

  16. Modeling Trends in Aerosol Direct Radiative Effects over the Northern Hemisphere using a Coupled Meteorology-Chemistry Model

    Science.gov (United States)

    Mathur, R.; Pleim, J.; Wong, D.; Hogrefe, C.; Xing, J.; Wei, C.; Gan, M.

    2013-12-01

    While aerosol radiative effects have been recognized as some of the largest sources of uncertainty among the forcers of climate change, the verification of the spatial and temporal variability of the magnitude and directionality of aerosol radiative forcing has remained challenging. A detailed investigation of the processes regulating aerosol distributions, their optical properties, and their radiative effects and verification of their simulated effects for past conditions relative to measurements is needed in order to build confidence in the estimates of the projected impacts arising from changes in both anthropogenic forcing and climate change. Anthropogenic emissions of primary aerosol and gaseous precursors have witnessed dramatic changes over the past two decades across the northern hemisphere. During the period 1990-2010, SO2 and NOx emissions across the US have reduced by about 66% and 50%, respectively, mainly due to Title IV of the U.S. Clean Air Act Amendments (CAA). In contrast, anthropogenic emissions have increased dramatically in many developing regions during this period. We conduct a systematic investigation of changes in anthropogenic emissions of primary aerosols and gaseous precursors over the past two decades, their impacts on trends and spatial heterogeneity in anthropogenic aerosol loading across the northern hemisphere troposphere, and subsequent impacts on regional radiation budgets. The coupled WRF-CMAQ model is applied for selected time periods spanning the period 1990-2010 over a domain covering the northern hemisphere and a nested finer resolution continental U.S. domain. The model includes detailed treatment of direct effects of aerosols on photolysis rates as well as on shortwave radiation. Additionally, treatment of aerosol indirect effects on clouds has also recently been implemented. A methodology is developed to consistently estimate U.S. emission inventories for the 20-year period accounting for air quality regulations as well as population trends, economic conditions, and technology changes in motor vehicles and electric power generation. Analysis of measurements of aerosol composition, radiation, and associated variables, over the past two decades will be presented which indicate significant reductions in the tropospheric aerosol burden as well as an increase in down-welling shortwave radiation at numerous sites across the U.S. Initial applications of the coupled WRF-CMAQ model for time-periods pre and post the implementation of CAA Title IV will be discussed and comparisons with measurements to assess the model's ability to capture trends in aerosol burden, composition, and direct aerosol effects on surface shortwave radiation will be presented.

  17. On a model in radiation hydrodynamics.

    Czech Academy of Sciences Publication Activity Database

    Ducomet, B.; Feireisl, Eduard; Ne?asová, Šárka

    2011-01-01

    Ro?. 28, ?. 6 (2011), s. 797-812. ISSN 0294-1449 R&D Projects: GA ?R GA201/09/0917 Institutional research plan: CEZ:AV0Z10190503 Keywords : radiation hydrodynamics * Navier-Stokes-Fourier system * weak solution Subject RIV: BA - General Mathematics Impact factor: 1.271, year: 2011 http://www.sciencedirect.com/science/article/pii/S0294144911000655

  18. On an incompressible model in radiation hydrodynamics.

    Czech Academy of Sciences Publication Activity Database

    Ducomet, B.; Ne?asová, Šárka

    2015-01-01

    Ro?. 38, ?. 4 (2015), s. 765-774. ISSN 0170-4214 R&D Projects: GA ?R GA13-00522S Institutional support: RVO:67985840 Keywords : radiation hydrodynamics * incompressible Navier-Stokes- Fourier system * weak solution Subject RIV: BA - General Mathematics Impact factor: 0.877, year: 2013 http://onlinelibrary.wiley.com/doi/10.1002/mma.3107/abstract

  19. A model of interband radiative transition.

    Czech Academy of Sciences Publication Activity Database

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

    2004-01-01

    Ro?. 56, ?. 3 (2004), s. 753-786. ISSN 0025-5645 R&D Projects: GA MŠk ME 482 Keywords : radiative transition * crystal spectral band * decay law Subject RIV: BE - Theoretical Physics Impact factor: 0.366, year: 2004

  20. Improved Solar-Radiation-Pressure Models for GPS Satellites

    Science.gov (United States)

    Bar-Sever, Yoaz; Kuang, Da

    2006-01-01

    A report describes a series of computational models conceived as an improvement over prior models for determining effects of solar-radiation pressure on orbits of Global Positioning System (GPS) satellites. These models are based on fitting coefficients of Fourier functions of Sun-spacecraft- Earth angles to observed spacecraft orbital motions.

  1. Dynamic model of counter flow air to air heat exchanger for comfort ventilation with condensation and frost formation

    DEFF Research Database (Denmark)

    Nielsen, Toke Ramme; Rose, JØrgen

    2009-01-01

    In cold climates heat recovery in the ventilation system is essential to reduce heating energy demand. Condensation and freezing occur often in efficient heat exchangers used in cold climates. To develop efficient heat exchangers and defrosting strategies for cold climates, heat and mass transfer must be calculated under conditions with condensation and freezing. This article presents a dynamic model of a counter flow air to air heat exchanger taking into account condensation and freezing and melting of ice. The model is implemented in Simulink and results are compared to measurements on a prototype heat exchanger for cold climates.

  2. Clearing the air: a model for investigating indoor air quality in Texas schools.

    Science.gov (United States)

    Petronella, Sharon A; Thomas, Rachel; Stone, James A; Goldblum, Randall M; Brooks, Edward G

    2005-06-01

    This pilot project focused on the assessment of indoor air quality at a local high school in Galveston, Texas, using methods based on guidelines for the U.S. Environmental Protection Agency's Indoor Air Quality Tools for Schools program. Tools for Schools, developed for evaluating and ensuring acceptable air quality for schools, takes a low-cost, minimal-involvement, primarily educational approach. The authors also compared the findings from this approach with the results of an air-sampling program. The overall goal was to determine if use of Tools for Schools was sufficient to identify conditions with the potential to cause adverse health effects. The primary objectives were to 1) establish an indoor air quality committee for the school to implement Tools for Schools assessments and management strategies, 2) collect air quality data in high-risk areas identified within the school by the indoor air quality committee, 3) collect outdoor air quality data at or in close proximity to the school, and 4) develop methods and instruments for assessing environmental risks associated with daily school attendance. Data were gathered on levels of formaldehyde and other volatile organic compounds (VOCs), ozone, particulate matter (PM10), mold, relative humidity, and temperature. Data values for each sampled pollutant were compared with federal standards, recommended values established by the American Conference of Governmental Industrial Hygienists for non-industrial populations, and effects screening levels developed by the Texas Commission on Environmental Quality. Levels of all VOCs except formaldehyde were found to be well within guidelines, as were ozone and particulate-matter levels. Mold, however, was widespread, including both common species and species associated with allergy and asthma, such as Aspergillus and Alternaria. In general, Tools for Schools provides an excellent foundation for a school indoor air quality program, although the authors did find it necessary to streamline data collection and did find that mold with the potential for adverse health effects was present, albeit not visible in some areas. PMID:15991683

  3. Numerical modelling of air movement in road tunnels

    International Nuclear Information System (INIS)

    The objective of the Mechanical Ventilation Systems (MVS) in highway tunnels is to provide tunnel patrons with a reasonable degree of comfort during normal operation and to assist in keeping tunnels safe during emergencies. Temperature, humidity, and air velocity are among the parameters that determine the tunnel environment and indicate the level of MVS performance. To investigate the performance of the current emergency ventilation strategies for an existing tunnel system in the event of a fire, a research project is being conducted at the National Research Council of Canada. The primary objectives of the study are: a) to assess and validate the ability of in-place emergency ventilation strategies to control smoke spread and minimize the impact of smoke on tunnel users; and b) to recommend guidelines for improving ventilation operation to maximize intervention effectiveness. This will allow future development of an intelligent ventilation system based on a pre-established scenario of ventilation activated using automatic fire detection. The research study includes two phases, numerical and experimental phases. The numerical phase will use a CFD model (Solvent) to study smoke ventilation in the tunnel. The experimental phase will be used to calibrate and validate the CFD model and to establish the boundary conditions for the numerical model. Solvent was used to model a ventilation scenario using existing data. The current paper presents the initial efforts to validater presents the initial efforts to validate the CFD model against onsite flow measurements conducted in the tunnel. The CFD model included aerodynamically significant physical features of the tunnel. (author)

  4. Theoretical and experimental drying of a cylindrical sample by applying hot air and infrared radiation in an inert medium fluidized bed

    Scientific Electronic Library Online (English)

    B., Honarvar; D., Mowla.

    2012-06-01

    Full Text Available Drying of a cylindrical sample in a fluidized bed dryer containing inert particles was studied. For this purpose, a pilot-scaled fluidized bed dryer was constructed in which two different heat sources, hot air and infrared radiation were applied, and pieces of carrot were chosen as test samples. The [...] heat transfer coefficient for cylindrical objects in a fluidized bed was also measured. The heat absorption coefficient for carrot was studied. The absorption coefficient can be computed by dividing the absorbed heat by the carrot to the heat absorbed for the water and black ink. In this regard, absorbed heat values by the carrot, water and black ink were used A mathematical model was proposed based on the mass and heat transfer phenomena within the drying sample. The results obtained by the proposed model were in favorable agreement with the experimental data.

  5. Theoretical and experimental drying of a cylindrical sample by applying hot air and infrared radiation in an inert medium fluidized bed

    Directory of Open Access Journals (Sweden)

    B. Honarvar

    2012-06-01

    Full Text Available Drying of a cylindrical sample in a fluidized bed dryer containing inert particles was studied. For this purpose, a pilot-scaled fluidized bed dryer was constructed in which two different heat sources, hot air and infrared radiation were applied, and pieces of carrot were chosen as test samples. The heat transfer coefficient for cylindrical objects in a fluidized bed was also measured. The heat absorption coefficient for carrot was studied. The absorption coefficient can be computed by dividing the absorbed heat by the carrot to the heat absorbed for the water and black ink. In this regard, absorbed heat values by the carrot, water and black ink were used A mathematical model was proposed based on the mass and heat transfer phenomena within the drying sample. The results obtained by the proposed model were in favorable agreement with the experimental data.

  6. Models of air-staged low NOx burners

    International Nuclear Information System (INIS)

    In order to reduce pollutant emissions produced by power plants it was proposed the optimization of the combustion process by developing externally air-staged burners which promote an initial oxygen-deficient zone to reduce the formation of both thermal and fuel derived NOx. The secondary combustion air circulate on two concentric paths: an external and an internal air flow, respectively, and flows across two adjustable swirls. The secondary air was swirled to create the internal recirculation zone that stabilizes the flame and controls its properties. This also permits maintaining an optimum ratio of air velocities at partial loads. This burner concept involved the creation of an oxygen-deficient zone by the injection of some of the combustion air through tertiary air ports. The paper presents the proposed low-NOx burners and the estimation of the performances of such burner types.(author). 5 figs., 1 tab., 6 refs

  7. Angular Dependency Model for the Meteosat Longwave Radiation

    Science.gov (United States)

    Clerbaux, N.; Dewitte, S.; Bertrand, C.; Caprion, D.; de Paepe, B.; Gonzalez, L.; Ipe, A.

    Accurate measurement of the outgoing longwave radiation OLR is of prime importance to improve the modelization of the climate system Indeed this radiative flux is a component of the Earth radiation budget together with the incoming solar flux and the reflected solar flux For the Meteosat field of view accurate measurements of the longwave broadband radiance are now available either directly from the Geostationary Earth radiation Budget GERB instrument or indirectly from the narrowband measurements of the SEVIRI or the Meteosat-7 imager Nevertheless angular modelisation of the radiation field is needed to estimate the flux from the directional measurement At this level the geostationary orbit is known to be an inconvenient as error in the angular modeling are introducing regional biases in the OLR a same place on Earth is always observed at the same viewing geometry In this poster we present the longwave angular modeling which has been developped implemented and is currently applied to the GERB instrument data The method is quite standard and has been widely used the limb-darkening is assessed using regression on the SEVIRI narrowband measurements the regression parameters being derived from radiative transfer computation In the frame of the GERB project an extensive validation of the thermal flux has been carried out and some limitations of the angular modeling have been identified There remain 2 main sources of angular conversion error i the inaccurate modeling of the semitransparent high clouds cirrus anisotropy and ii the 3-dimensional

  8. Monitoring of gross alpha in the air and exposure gamma radiation on and around the coal fire power at Paiton

    International Nuclear Information System (INIS)

    Coal is burned in furnace operating at up to 1,700 oC in order to produce electrical energy and ash (bottom ash and fly-ash). The fly-ash is released to the atmosphere or environment around the coal fire power. Therefore, the environmental radioactivity monitoring should be carried out for gross alpha in the air and exposure gamma radiation. The measurement of gross alpha have been carried out using the alpha scintillation counter with the ZnS(Ag) detector, and measurement of gamma radiation using the high pressure ion chamber. The results obtained showed that the gross alpha in the air were the ranging from (7.1 ± 1,2) mBq m-3 to (12.2 ± 1.9) mBq m-3 and the exposure gamma radiation were (3.69 ± 0.11) ?R/h to (9.55 ± 0.15) ?R/h. The data were still lower than the limit of the maximum permissible concentration and annual intake for breathing but the gross alpha data were higher than in the nuclear installations. (authors)

  9. Design and construction of a miniature dosimeter for the study of the effects of air cavities in radiation therapy

    International Nuclear Information System (INIS)

    A miniature dosimeter utilizing silicon p-i-n chips was designed for performing in vivo measurements in radiation therapy. The dosimeter, which is less than 2 mm in diameter, can be inserted into patients and phantoms for rapid measurements. An important advantage of this type of dosimeter over thermoluminescent dosimeters and miniature ionization chambers is the instant readout and the elimination of a waiting period between measurements. Different arrangements of the p-i-n chips were explored in an effort to obtain minimal detector size, directional independence and a large signal. The physical parameters of the dosimeters were examined. These include temperature effect, directional sensitivity, effect of encapsulating material, energy and dose rate dependence and linearity of response. The dosimeters, which were calibrated against a National Bureau of Standards calibrated Victoreen ionization chamber, were used to investigate some of the effects of air cavities in a radiation treatment volume. These include change in backscatter and build-up characteristics. Geometrical as well as anatomical phantoms of tissue equivalent material were used for measurements. Cobalt-60 gamma rays and 8 and 17 MeV photons from a linear accelerator were used as the radiation source for the various measurements. Measurements were taken to determine the variation in dose caused by changing the dimensions and geometry of an air cavity

  10. Mathematical model and simulations of radiation fluxes from buried radionuclides

    International Nuclear Information System (INIS)

    A mathematical model and a simple Monte Carlo simulations were developed to predict radiation fluxes from buried radionuclides. The model and simulations were applied to measured (experimental) data. The results of the mathematical model showed good acceptable order of magnitude agreement. A good agreement was also obtained between the simple simulations and the experimental results. Thus, knowing the radionuclide distribution profiles in soil from a core sample, it can be applied to the model or simulations to estimate the radiation fluxes emerging from the soil surface. (author)

  11. Assessment of the effect of air pollution controls on trends in shortwave radiation over the United States from 1995 through 2010 from multiple observation networks

    Science.gov (United States)

    Long-term data sets of all-sky and clear-sky downwelling shortwave (SW) radiation, cloud cover fraction, and aerosol optical depth (AOD) were analyzed together with surface concentrations from several networks (e.g., Surface Radiation Budget Network (SURFRAD), Clean Air Status an...

  12. Microwave landing system modeling with application to air traffic control

    Science.gov (United States)

    Poulose, M. M.

    1991-01-01

    Compared to the current instrument landing system, the microwave landing system (MLS), which is in the advanced stage of implementation, can potentially provide significant fuel and time savings as well as more flexibility in approach and landing functions. However, the expanded coverage and increased accuracy requirements of the MLS make it more susceptible to the features of the site in which it is located. An analytical approach is presented for evaluating the multipath effects of scatterers that are commonly found in airport environments. The approach combines a multiplane model with a ray-tracing technique and a formulation for estimating the electromagnetic fields caused by the antenna array in the presence of scatterers. The model is applied to several airport scenarios. The reduced computational burden enables the scattering effects on MLS position information to be evaluated in near real time. Evaluation in near real time would permit the incorporation of the modeling scheme into air traffic control automation; it would adaptively delineate zones of reduced accuracy within the MLS coverage volume, and help establish safe approach and takeoff trajectories in the presence of uneven terrain and other scatterers.

  13. Applicability of experimental models for cellular radiation targets

    Energy Technology Data Exchange (ETDEWEB)

    Lett, J.T. [Colorado State Univ., Fort Collins, CO (United States)

    1995-12-31

    Rigorous development of a unifying theory of cellular sensitivity to ionizing radiations requires a proper understanding of the early phase of the chemical stage of radiation action where rapid chemical changes follow the deposition of radiant energy in the cellular radiation target. Monte Carlo simulations of radiation transport processes and track structures can describe the physical stage of radiation action, but such analyses have not been extended as yet to the processes of charge and energy transfer associated with the early chemical events. Over the last three to four decades, a variety of experimental models have been used to approximate, or simulate, radiation damage to nuclear chromatin in vivo. They fall into three main categories: (1) hydrated DNA and/or deoxyribonucleoprotein; (2) frozen solutions of DNA; (3) aqueous solutions of DNA and/or deoxyribonucleoprotein containing radioprotectors believed to act primarily as radical scavengers, mainly of {center_dot}OH. Some of the difficulties inherent to models in categories 1 and 3 are examined here. Emphasis in the first case is upon the preparation of the model system and in the second is upon the interpretation of the actual radiation responses observed. All the information utilized is taken from the published literature.

  14. Solar radiation and shadow modelling with adaptive triangular meshes

    Energy Technology Data Exchange (ETDEWEB)

    Montero, G.; Escobar, J.M.; Rodriguez, E.; Montenegro, R. [University Institute for Intelligent Systems and Numerical Applications in Engineering, University of Las Palmas de Gran Canaria, Campus Universitario de Tafira, 35017 Las Palmas de Gran Canaria (Spain)

    2009-07-15

    In this work, we propose a numerical model for generating solar radiation maps with the use of 2-D adaptive meshes of triangles. These triangulations are constructed by using a refinement/derefinement procedure in accordance with the variations of terrain surface orography and albedo. This discretization has the advantage of defining the terrain characteristics with a minimum number of points, which reduces the computational cost for a given accuracy. Moreover, the model takes into account the effect of shadows for each time step, which are detected by analysing the crossing of the trajectory of the shaft of light with the triangles of the mesh. Thus, the solar radiation is first computed for clear-sky considering the different components of radiation, that is, beam, diffuse and reflected radiations. From the results of clear-sky radiation, the real-sky radiation is computed daily in terms of the clear-sky index. The maps of clear-sky index are obtained from a spatial interpolation of observational data that are available for each day at several points of the zone under consideration. Finally, the solar radiation maps of a month are calculated from the daily results. We illustrate the performance of the model with a numerical experiment related to an episode on the island of Gran Canaria. (author)

  15. AN ANALYTIC RADIATIVE-CONVECTIVE MODEL FOR PLANETARY ATMOSPHERES

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, Tyler D. [Astronomy Department, University of Washington, Box 351580, Seattle, WA 98195-1580 (United States); Catling, David C., E-mail: robinson@astro.washington.edu [Department of Earth and Space Sciences, University of Washington, Box 351310, Seattle, WA 98195-1310 (United States)

    2012-09-20

    We present an analytic one-dimensional radiative-convective model of the thermal structure of planetary atmospheres. Our model assumes that thermal radiative transfer is gray and can be represented by the two-stream approximation. Model atmospheres are assumed to be in hydrostatic equilibrium, with a power-law scaling between the atmospheric pressure and the gray thermal optical depth. The convective portions of our models are taken to follow adiabats that account for condensation of volatiles through a scaling parameter to the dry adiabat. By combining these assumptions, we produce simple, analytic expressions that allow calculations of the atmospheric-pressure-temperature profile, as well as expressions for the profiles of thermal radiative flux and convective flux. We explore the general behaviors of our model. These investigations encompass (1) worlds where atmospheric attenuation of sunlight is weak, which we show tend to have relatively high radiative-convective boundaries; (2) worlds with some attenuation of sunlight throughout the atmosphere, which we show can produce either shallow or deep radiative-convective boundaries, depending on the strength of sunlight attenuation; and (3) strongly irradiated giant planets (including hot Jupiters), where we explore the conditions under which these worlds acquire detached convective regions in their mid-tropospheres. Finally, we validate our model and demonstrate its utility through comparisons to the average observed thermal structure of Venus, Jupiter, and Titan, and by comparing computed flux profiles to more complex models.

  16. A radiation heat transfer model for the SCDAP code

    International Nuclear Information System (INIS)

    A radiation heat transfer model has been developed for severe fuel damage analysis that accounts for anisotropic effects of reflected radiation. The model simplifies the view factor calculation, which results in significant savings in computational cost with little loss of accuracy. Radiation heat transfer rates calculated by the isotropic and anistropic models compare reasonably well with those calculated by other models. The model is applies to an experimental nuclear rod bundle during a slow boil-off of the coolant liquid, a situation encountered during a loss-of-coolant accident with severe fuel damage. At lower temperatures and also lower temperature gradients in the core, the anisotropic effect was not found to be significant

  17. Equivalent circuit model of radiative heat transfer

    OpenAIRE

    Maslovski, Stanislav I.; Simovski, Constantin R.; Tretyakov, Sergei A.

    2012-01-01

    Here, we develop a theory of radiative heat transfer based on an equivalent electrical network representation for the hot material slabs in an arbitrary multilayered environment with arbitrary distribution of temperatures and electromagnetic properties among the layers. Our approach is fully equivalent to the known theories operating with the fluctuating current density, while being significantly simpler in analysis and applications. A practical example of the near-infrared ...

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

    OpenAIRE

    Smith Jim T

    2007-01-01

    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 a...

  19. Radiation therapy of head and neck tumors: a randomized study of treatment in air vs treatment in hyperbaric oxygen

    International Nuclear Information System (INIS)

    A randomized study of squamous cell carcinoma of the head and neck, with the exception of T1 vocal cord lesions, compared 23 patients who were treated in air with doses of 250 rad four times a week to 6250 rad, to 21 patients who were treated at three atmospheres of hyperbaric oxygen with 12 x 400-rad fractions in approximately 32 days. Distribution by anatomic site and age was comparable. Distribution by stage was in favor of the air group since five Stage I patients were found in the air group but none in the hyperbaric oxygen group. The sex distribution was uneven - 15 males to eight females in the air group and eight males to 13 females in the oxygen group. All patients were followed for a minimum of two years; most patients were followed more than five years, with indefinite followup. The 12 x 400-rad schedule in four and one-half weeks in the hyperbaric oxygen group proved to be well tolerated without any significant increase in complications. Radiation myelitis can be avoided by limiting the spinal cord dose to 7 x 400 rad

  20. Plasmonic-cavity model for radiating nano-rod antennas

    DEFF Research Database (Denmark)

    Peng, Liang; Mortensen, N. Asger

    2014-01-01

    In this paper, we propose the analytical solution of nano-rod antennas utilizing a cylindrical harmonics expansion. By treating the metallic nano-rods as plasmonic cavities, we derive closed-form expressions for both the internal and the radiated fields, as well as the resonant condition and the radiation efficiency. With our theoretical model, we show that besides the plasmonic resonances, efficient radiation takes advantage of (a) rendering a large value of the rods' radius and (b) a central-fed profile, through which the radiation efficiency can reach up to 70% and even higher in a wide frequency band. Our theoretical expressions and conclusions are general and pave the way for engineering and further optimization of optical antenna systems and their radiation patterns.

  1. A radiative diffusion model for laser-compression simulations

    International Nuclear Information System (INIS)

    A radiation diffusion package is described which can handle the transport of continuum radiation arising from free-free and free-bound transitions in a laser-compressed plasma. This model has been incorporated into MEDUSA, a two temperature, 1-D Lagrangian computer code, and numerous computer runs have been carried out to study the effect of radiative preheat on target compression. The calculations show that in compression of a 10-?g solid carbon microsphere the radiation effects reduce the final target density by up to a factor of 6. In the case of a neon filled thin glass microballoon, the radiative preheat reduces maximum neon density by a factor of 3 while the maximum shell density drops from 105 Kg/m3 to 1.8 x 104 Kg/m3. (author)

  2. Comparison of the standards of air kerma of the OMH and the BIPM for 60Co gamma radiation

    International Nuclear Information System (INIS)

    A direct comparison between the standards for air kerma of the Orszagos Meresugyi Hivatal (OMH) and of the Bureau International des Poids et Mesures (BIPM) has been carried out in the 60Co radiation beams of the BIPM. The result, expressed as a ratio of the OMH and the BIPM standards for air kerma, indicates a relative difference of 10.9 x 10-3 with a combined standard uncertainty of 2.2 x 10-3. This new result agrees at the level of 0.4 x 10-3 with the earlier direct comparisons performed in 1986 and 1994, as modified in 2001 by the application of wall and axial non-uniformity correction factors, calculated for the OMH standards using the Monte Carlo method. (authors)

  3. Comparison of the standards of air kerma of the LNE-LNHB and the BIPM for 60Co gamma radiation

    International Nuclear Information System (INIS)

    A direct comparison of the standards for air kerma of the Laboratoire National de Metrologie et d'Essais - Laboratoire National Henri Becquerel (LNE-LNHB), France and of the Bureau International des Poids et Mesures (BIPM) was carried out in the 60Co radiation beam of the BIPM in December 2003. The results, expressed as ratios of the LNE-LNHB and the BIPM standards for air kerma, indicate a relative difference of 3.5 x 10-3 with a combined standard uncertainty of 2.7 x 10-3. The earlier direct comparison in 60Co ? rays, made in 1993, resulted in an agreement of the two standards within 2.5 x 10-3. (authors)

  4. Long-term patterns in dissolved organic carbon in boreal lakes: the role of incident radiation, precipitation, air temperature, southern oscillation and acid deposition

    OpenAIRE

    J. J. Hudson; Dillon, P. J.; Somers, K. M.

    2003-01-01

    Both lake-specific (e.g. pH) and regional (e.g. precipitation) factors affect DOC concentration and pattern. Using annual DOC concentration in nine boreal lakes in the ice-free season, the potential influences of five regional factors, air temperature, precipitation, SO4 deposition, solar radiation (photosynthetically active radiation, or PAR) and the southern oscillation index (SOI) have been explored through multiple regression. Mean solar radiation, winter precipitation and summer precipit...

  5. Longwave radiation budget at the Baltic Sea surface from satellite and atmospheric model data

    OpenAIRE

    Tomasz Zapadka; Adam Kr??el; Bogdan Wo?niak

    2008-01-01

    The net longwave radiation flux LW?? in the Baltic Sea in 2001 has beensubjected to spatial and temporal analysis. Maps of the mean monthlyLW?? over the Baltic were drawn using the new semi-empirical formula for the Baltic Sea (Zapadka et al. 2007).The input data for the formula, such as sea surface and air temperatures,and cloud cover, were obtained from the Tiros N/NOAA and METEOSAT 7 satellites and from the UMPL forecast model (see http://meteo.icm.edu.pl). The mean ann...

  6. The Atlanta Urban Heat Island Mitigation and Air Quality Modeling Project: How High-Resoution Remote Sensing Data Can Improve Air Quality Models

    Science.gov (United States)

    Quattrochi, Dale A.; Estes, Maurice G., Jr.; Crosson, William L.; Khan, Maudood N.

    2006-01-01

    The Atlanta Urban Heat Island and Air Quality Project had its genesis in Project ATLANTA (ATlanta Land use Analysis: Temperature and Air quality) that began in 1996. Project ATLANTA examined how high-spatial resolution thermal remote sensing data could be used to derive better measurements of the Urban Heat Island effect over Atlanta. We have explored how these thermal remote sensing, as well as other imaged datasets, can be used to better characterize the urban landscape for improved air quality modeling over the Atlanta area. For the air quality modeling project, the National Land Cover Dataset and the local scale Landpro99 dataset at 30m spatial resolutions have been used to derive land use/land cover characteristics for input into the MM5 mesoscale meteorological model that is one of the foundations for the Community Multiscale Air Quality (CMAQ) model to assess how these data can improve output from CMAQ. Additionally, land use changes to 2030 have been predicted using a Spatial Growth Model (SGM). SGM simulates growth around a region using population, employment and travel demand forecasts. Air quality modeling simulations were conducted using both current and future land cover. Meteorological modeling simulations indicate a 0.5 C increase in daily maximum air temperatures by 2030. Air quality modeling simulations show substantial differences in relative contributions of individual atmospheric pollutant constituents as a result of land cover change. Enhanced boundary layer mixing over the city tends to offset the increase in ozone concentration expected due to higher surface temperatures as a result of urbanization.

  7. ABSORCIÓN POR OZONO Y DISPERSIÓN POR AIRE DE LA RADIACIÓN SOLAR ULTRAVIOLETA B / OZONE ABSORPTION AND PURE AIR SCATTERING OF SOLAR ULTRAVIOLETA B RADIATION

    Scientific Electronic Library Online (English)

    Julio César, González Navarrete; Julián, Salamanca.

    2011-12-30

    Full Text Available Para los casos eventuales de falta de información experimental, se presenta una alternativa para poder disponer de datos confiables y validables de los coeficientes de absorción por ozono y de dispersión por aire puro de la radiación solar ultravioleta B (radiación UV-B); dichos coeficientes son req [...] ueridos para la estimación de la columna total de ozono al aplicar la espectrofotometría Dobson. La alternativa propuesta tiene que ver con el uso cuidadoso de interpolación, aplicada a series de datos, debidamente validados. Se plantea un ensayo de validación indirecta aplicando la metodología Dobson a la información obtenida de esta manera y así determinar el ozono total. Abstract in english For eventual cases of lack of experimental data, an alternative in order to have reliable and verifiable results for both ozone absorption and pure air dispersion coefficients of solar ultraviolet B radiation (UV-B) is shown; these coefficients are required to estimate ozone total column in Dobson s [...] pectrophotometry. The proposed alternative has to do with the careful use of interpolation applied to sets of properly validated data. We present an indirect validation test using Dobson methodology to the information obtained in this manner and thus determine the total ozone.

  8. DEVELOPMENT OF MESOSCALE AIR QUALITY SIMULATION MODELS. VOLUME 4. USER'S GUIDE TO MESOGRID (MESOSCALE GRID) MODEL

    Science.gov (United States)

    MESOGRID is a regional-scale grid model, based on the Egan-Mahoney method of moments, especially designed to simulate the air quality impacts of multiple sources at long transport distances. Highly user-oriented, MESOGRID provides a range of flexible options, and its clean, modul...

  9. DEVELOPMENT OF MESOSCALE AIR QUALITY SIMULATION MODELS. VOLUME 3. USER'S GUIDE TO MESOPUFF (MESOSCALE PUFF) MODEL

    Science.gov (United States)

    MESOPUFF is a variable-trajectory regional-scale Gaussian puff model especially designed to simulate the air quality impacts of multiple point sources at long transport distances. Highly user-oriented, MESOPUFF provides a range of flexible options, and its clean, modular structur...

  10. SRADLIB: A C Library for Solar Radiation Modelling

    Energy Technology Data Exchange (ETDEWEB)

    Balenzategui, J. L. [Ciemat. Madrid (Spain)

    2000-07-01

    This document shows the result of an exhaustive study about the theoretical and numerical models available in the literature about solar radiation modelling. The purpose of this study is to develop or adapt mathematical models describing the solar radiation specifically for Spain locations as well as to create computer tools able to support the labour of researchers or engineers needing solar radiation data to solve or improve the technical or energetic performance of solar systems. As results of this study and revision, a C library (SRADLIB) is presented as a key for the compilation of the mathematical models from different authors, for the comparison among the different approaches and for its application in computer programs. Different topics related to solar radiation and its modelling are first discussed, including the assumptions and conventions adopted and describing the most accepted and used current state-of-the-art models. some typical problems in the numerical calculation of radiation values are also posed with the proposed solution. The document includes next a complete reference of the developed functions, with many examples of application and calculus. (Author) 24 refs.

  11. SRADLIB: A C Library for Solar Radiation Modelling

    International Nuclear Information System (INIS)

    This document shows the result of an exhaustive study about the theoretical and numerical models available in the literature about solar radiation modelling. The purpose of this study is to develop or adapt mathematical models describing the solar radiation specifically for Spain locations as well as to create computer tools able to support the labour of researchers or engineers needing solar radiation data to solve or improve the technical or energetic performance of solar systems. As result of this study and revision, a C library (SRADLIB) is presented as a key tool for the compilation of the mathematical models from different authors, for the comparison among the different approaches and for its application in computer programs. Different topics related to solar radiation and its modelling are first discussed, including the assumptions and conventions adopted and describing the most accepted and used current state-of-the-art models. Some typical problems in the numerical calculation of radiation values are also posed with the proposed solution. The document includes next a complete reference of the developed functions, with many examples of application and calculus. (Author) 24 refs

  12. Modelling the Air Transport with Complex Networks: a short review

    CERN Document Server

    Zanin, Massimiliano

    2013-01-01

    Air transport is a key infrastructure of modern societies. In this paper we review some recent approaches to air transport, which make extensive use of theory of complex networks. We discuss possible networks that can be defined for the air transport and we focus our attention to networks of airports connected by flights. We review several papers investigating the topology of these networks and their dynamics for time scales ranging from years to intraday intervals, and consider also the resilience properties of air networks to extreme events. Finally we discuss the results of some recent papers investigating the dynamics on air transport network, with emphasis on passengers traveling in the network and epidemic spreading mediated by air transport.

  13. Comparison of the standards for air kerma of the ENEA-INMRI and the BIPM for 60Co gamma radiation

    International Nuclear Information System (INIS)

    A comparison of the standards of air kerma of the Istituto Nazionale di Metrologia delle Radiazioni Ionizzanti of the Ente per le Nuove Tecnologie, l'Energia e l'Ambiente, Italy (ENEA-INMRI) and of the Bureau International des Poids et Mesures (BIPM) has been carried out in 60Co radiation. The comparison result, declared in 2002, is 1.0103 (0.0026). The difference between the ENEA-INMRI and BIPM standards is consistent with the various changes that have been introduced since the previous comparisons that were in agreement within the comparison uncertainties. (authors)

  14. Investigation of a spatial distribution function of Cherenkov radiation of extensive air showers at a Samarkand State Univirsity device

    International Nuclear Information System (INIS)

    The spatial distribution function (SDF) of the Cherenkov radiation of extensive air showers (EAS) in the primary energy range of 1014-1016 eV is studied using the Samarkand device designed for the investigation of EAS. The SDF are presented for two shower groups in a particle number and for zenith angles of theta 6 and for the second group N is equal to 2.23x105. The shower maximum depth is found. The magnitude of 580+-50 gxcm-2 is obtained for the first group and 400+-50 gxcm-2 is obtained for the second group

  15. Air quality over Europe: modelling gaseous and particulate pollutants

    Directory of Open Access Journals (Sweden)

    E. Tagaris

    2013-09-01

    Full Text Available Air quality over Europe using Models-3 (i.e., CMAQ, MM5, SMOKE modelling system is performed for winter (i.e., January 2006 and summer (i.e., July 2006 months with the 2006 TNO gridded anthropogenic emissions database. Higher ozone mixing ratios are predicted in southern Europe while higher NO2 levels are simulated over western Europe. Elevated SO2 values are simulated over eastern Europe and higher PM2.5 concentrations over eastern and western Europe. Regional average results suggest that NO2 and PM2.5 are underpredicted, SO2 is overpredicted, while Max8hrO3 is overpredicted for low mixing ratios and is underpredicted for the higher mixing ratios. However, in a number of countries observed and predicted values are in good agreement for the pollutants examined here. Speciated PM2.5 components suggest that NO3 is dominant during winter over western Europe and in a few eastern countries due to the high NO2 mixing ratios. During summer NO3 is dominant only in regions with elevated NH3 emissions. For the rest of the domain SO4 is dominant. Low OC concentrations are simulated mainly due to the uncertain representation of SOA formation.

  16. Dynamic Model of the BIO-Plex Air Revitalization System

    Science.gov (United States)

    Finn, Cory; Meyers, Karen; Duffield, Bruce; Luna, Bernadette (Technical Monitor)

    2000-01-01

    The BIO-Plex facility will need to support a variety of life support system designs and operation strategies. These systems will be tested and evaluated in the BIO-Plex facility. An important goal of the life support program is to identify designs that best meet all size and performance constraints for a variety of possible future missions. Integrated human testing is a necessary step in reaching this goal. System modeling and analysis will also play an important role in this endeavor. Currently, simulation studies are being used to estimate air revitalization buffer and storage requirements in order to develop the infrastructure requirements of the BIO-Plex facility. Simulation studies are also being used to verify that the envisioned operation strategy will be able to meet all performance criteria. In this paper, a simulation study is presented for a nominal BIO-Plex scenario with a high-level of crop growth. A general description of the dynamic mass flow model is provided, along with some simulation results. The paper also discusses sizing and operations issues and describes plans for future simulation studies.

  17. Radiation dose modeling using IGRIP and Deneb/ERGO

    International Nuclear Information System (INIS)

    The Radiological Environment Modeling System (REMS) quantifies dose to humans in radiation environments using the IGRIP (Interactive Graphical Robot Instruction Program) and Deneb/ERGO (Ergonomics) simulation software products. These commercially available products are augmented with custom C code to provide the radiation exposure information to and collect the radiation dose information from the workcell simulations. The emphasis of this paper is on the IGRIP and Deneb/ERGO parts of REMS, since that represents the extension to existing capabilities developed by the authors. Through the use of any radiation transport code or measured data, a radiation exposure input database may be formulated. User-specified IGRIP simulations utilize these database files to compute and accumulate dose to human devices (Deneb's ERGO human) during simulated operations around radiation sources. Timing, distances, shielding, and human activity may be modeled accurately in the simulations. The accumulated dose is recorded in output files, and the user is able to process and view this output. REMS was developed because the proposed reduction in the yearly radiation exposure limit will preclude or require changes in many of the manual operations currently being utilized in the Weapons Complex. This is particularly relevant in the area of dismantlement activities at the Pantex Plant in Amarillo, TX. Therefore, a capability was needed to be able to quantify the dose associated with certain manual processes so that the benefits of automation could be identified and understood

  18. Individual particle analysis of coarse air suspended particulate material by synchrotron radiation X-ray micro fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Silvana; Melo Junior, Ariston [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Civil, Arquitetura e Urbanismo. Dept. de Recursos Hidricos]. E-mail: silvana@fec.unicamp.br; Perez, Carlos Alberto [Laboratorio Nacional de Luz Sincrotron (LNLS), Campinas, SP (Brazil)]. E-mail: perez@lnls.br; Vives, Ana Elisa S. de [Universidade Metodista de Piracicaba (UNIMEP), Santa Barbara D' Oeste, SP (Brazil). Faculdade de Engenharia, Arquitetura e Urbanismo]. E-mail: aesvives@unimep.br; Nascimento Filho, Virgilio F. [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil). Lab. de Instrumentacao Nuclear]. E-mail: virgilio@cena.usp.br

    2005-07-01

    The purpose of this work is evaluate the size of individual particles present in the air suspended particulate material collected in Campinas, Sao Paulo State, and analyze quantitatively the particles using the synchrotron radiation X-ray micro fluorescence ({mu}-SRXRF) associated with the fundamental parameter method to correct attenuation/absorption effects by the matrix. The particles analyzed have size between 50-10 {mu}m and to perform the spatial distribution a white beam of synchrotron radiation condensed by a conical capillary (13 {mu}m diameter) was used. For the quantitative analysis punctual measures in thin films standards in Mylar subtract were performed. The elements detected were Si, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ba and Pb. (author)

  19. Individual particle analysis of coarse air suspended particulate material by synchrotron radiation X-ray micro fluorescence

    International Nuclear Information System (INIS)

    The purpose of this work is evaluate the size of individual particles present in the air suspended particulate material collected in Campinas, Sao Paulo State, and analyze quantitatively the particles using the synchrotron radiation X-ray micro fluorescence (?-SRXRF) associated with the fundamental parameter method to correct attenuation/absorption effects by the matrix. The particles analyzed have size between 50-10 ?m and to perform the spatial distribution a white beam of synchrotron radiation condensed by a conical capillary (13 ?m diameter) was used. For the quantitative analysis punctual measures in thin films standards in Mylar subtract were performed. The elements detected were Si, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ba and Pb. (author)

  20. Risk assessment of intake of foods and soil, and air radiation dose after Fukushima Daiichi nuclear disaster

    International Nuclear Information System (INIS)

    Risk assessment of soil contaminated with radionuclides, due to the accident of Fukushima nuclear power plant after the earthquake on March 11, 2011, was carried out by considering consumption of the contaminated food. The exposure routes were set as food intake, ingestion and inhalation of soil particles, and external radiation from the ground. As a result, exposures by ingestion, and inhalation of soil particles were negligible, and exposure by food intake and external exposure from the ground were comparatively large. This study shows air dose by the accident should be under 0.2 ?Sv/hour in order to control the radiation dose with consumption of food under 1 ?Sv/year. (author)

  1. Air traffic conflict resolution via light propagation modeling

    OpenAIRE

    Dougui, Nour Elhouda; Delahaye, Daniel; Mongeau, Marcel; Puechmorel, Stéphane

    2010-01-01

    The analysis of air traffic growth expects a doubling in the flights number over the next 20 years. The Air Traffic Management (ATM) will therefore have to absorb this additional burden and to increase the airspace capacity, while ensuring at least equivalent standards of safety. The European project SESAR was initiated to propose solutions to this problem. It relies on a new concept of air traffic control, known as 4D (3D + time) trajectory planning, which consists in exploiting the new Flig...

  2. The problem of multicollinearity in horizontal solar radiation estimation models and a new model for Turkey

    International Nuclear Information System (INIS)

    Highlights: • Impacts of multicollinearity on solar radiation estimation models are discussed. • Accuracy of existing empirical models for Turkey is evaluated. • A new non-linear model for the estimation of average daily horizontal global solar radiation is proposed. • Estimation and prediction performance of the proposed and existing models are compared. - Abstract: Due to the considerable decrease in energy resources and increasing energy demand, solar energy is an appealing field of investment and research. There are various modelling strategies and particular models for the estimation of the amount of solar radiation reaching at a particular point over the Earth. In this article, global solar radiation estimation models are taken into account. To emphasize severity of multicollinearity problem in solar radiation estimation models, some of the models developed for Turkey are revisited. It is observed that these models have been identified as accurate under certain multicollinearity structures, and when the multicollinearity is eliminated, the accuracy of these models is controversial. Thus, a reliable model that does not suffer from multicollinearity and gives precise estimates of global solar radiation for the whole region of Turkey is necessary. A new nonlinear model for the estimation of average daily horizontal solar radiation is proposed making use of the genetic programming technique. There is no multicollinearity problem in the new model, and its estimation accuracy is better than the revisited models in terms of numerous statistical performance measures. According to the proposed model, temperature, precipitation, altitude, longitude, and monthly average daily extraterrestrial horizontal solar radiation have significant effect on the average daily global horizontal solar radiation. Relative humidity and soil temperature are not included in the model due to their high correlation with precipitation and temperature, respectively. While altitude has the highest relative impact on the average daily horizontal solar radiation, impact of temperature is greater than that of both longitude and precipitation

  3. A model code for the radiative theta pinch

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S., E-mail: leesing@optusnet.com.au [INTI International University, 71800 Nilai (Malaysia); Institute for Plasma Focus Studies, 32 Oakpark Drive, Chadstone 3148 Australia (Australia); Physics Department, University of Malaya, Kuala Lumpur (Malaysia); Saw, S. H. [INTI International University, 71800 Nilai (Malaysia); Institute for Plasma Focus Studies, 32 Oakpark Drive, Chadstone 3148 Australia (Australia); Lee, P. C. K. [Nanyang Technological University, National Institute of Education, Singapore 637616 (Singapore); Akel, M. [Department of Physics, Atomic Energy Commission, Damascus, P. O. Box 6091, Damascus (Syrian Arab Republic); Damideh, V. [INTI International University, 71800 Nilai (Malaysia); Khattak, N. A. D. [Department of Physics, Gomal University, Dera Ismail Khan (Pakistan); Mongkolnavin, R.; Paosawatyanyong, B. [Department of Physics, Faculty of Science, Chulalongkorn University, Bangkok 10140 (Thailand)

    2014-07-15

    A model for the theta pinch is presented with three modelled phases of radial inward shock phase, reflected shock phase, and a final pinch phase. The governing equations for the phases are derived incorporating thermodynamics and radiation and radiation-coupled dynamics in the pinch phase. A code is written incorporating correction for the effects of transit delay of small disturbing speeds and the effects of plasma self-absorption on the radiation. Two model parameters are incorporated into the model, the coupling coefficient f between the primary loop current and the induced plasma current and the mass swept up factor f{sub m}. These values are taken from experiments carried out in the Chulalongkorn theta pinch.

  4. A model code for the radiative theta pinch

    International Nuclear Information System (INIS)

    A model for the theta pinch is presented with three modelled phases of radial inward shock phase, reflected shock phase, and a final pinch phase. The governing equations for the phases are derived incorporating thermodynamics and radiation and radiation-coupled dynamics in the pinch phase. A code is written incorporating correction for the effects of transit delay of small disturbing speeds and the effects of plasma self-absorption on the radiation. Two model parameters are incorporated into the model, the coupling coefficient f between the primary loop current and the induced plasma current and the mass swept up factor fm. These values are taken from experiments carried out in the Chulalongkorn theta pinch

  5. Saturable repair models of radiation action in mammalian cells

    International Nuclear Information System (INIS)

    Most quantitative models of radiation action in mammalian cells make the implicit assumption that all relevant repair processes proceed in a dose-independent manner. Thus it is implicitly assumed that the repair processes (1) follow totally unsaturated kinetics, (2) are not themselves inactivated by the radiation, and (3) are not enhanced by the presence of radiation damage. Contradiction of any of these three assumptions could have important theoretical and practical implications. The possible relevance of (1) and (2) in mammalian cells is discussed by considering a selection of saturable repair (and related) models. Repair inactivation is improbable, but repair saturation provides a ready explanation of common radiobiological phenomena without the need for the existence of sublethal damage. Furthermore, such models can explain additional phenomena which appear as contradictions to some sublethal damage models. Recent experiments by Wheeler and Wierowski have demonstrated the existence of dose-dependent repair of DNA damage in mammalian cells

  6. Different radiation impedance models for finite porous materials

    DEFF Research Database (Denmark)

    Nolan, Melanie; Jeong, Cheol-Ho

    2015-01-01

    The Sabine absorption coefficients of finite absorbers are measured in a reverberation chamber according to the international standard ISO 354. They vary with the specimen size essentially due to diffraction at the specimen edges, which can be seen as the radiation impedance differing from the infinite case. Thus, in order to predict the Sabine absorption coefficients of finite porous samples, one can incorporate models of the radiation impedance. In this study, different radiation impedance models are compared with two experimental examples. Thomasson’s model is compared to Rhazi’s method when coupled to the transfer matrix method (TMM). These methods are found to yield comparable results when predicting the Sabine absorption coefficients of finite porous materials. Discrepancies with measurement results can essentially be explained by the unbalance between grazing and non-grazing sound field in the reverberation chamber. A better agreement is found when incorporating the modal decomposition method to the models.

  7. Pitfalls in radiation modeling of Z-pinch plasmas

    International Nuclear Information System (INIS)

    Over the last three decades there has been a quantum jump in the production of x-rays from pulsed power driven Z-pinch plasmas. Total radiative yields have gone from a few kilojoules to almost two megajoules. This increase occurred as a result of higher current drivers coupled with improvements in our understanding of the issues most relevant to good load design. Critical analyses of experimental data have led to a better understanding of the load dynamics, which includes all phases of load evolution extending from the cold start to the final collapsed phase and the emission of the x-ray pulse. A Z pinch is a deceptively simple device that has a very complex plasma dynamics. It can be a platform for demonstrating a variety of textbook plasma instabilities. However, its primary application in the present context is as an intense source of x-ray radiation. Therefore it is attractive both as a direct source of x-rays and for creating hohlraum conditions for plasma fusion experiments. After a few historical comments are offered on how radiation has been treated in modeling Z pinches, some of the methodologies and models that are employed in this endeavor are discussed. These include both nonLTE and LTE ionization dynamic models and escape probability radiation transport and LTE radiation diffusion models. To illustrate their use, comparisons are made between experimental data from a stainless steel wire array pinch implosion and 1-D MHD calculations that employ these mode-D MHD calculations that employ these models. The consequences that stem from the compromises and trade-offs that result from the different approximations used in these models are addressed. We will explore the role that radiation plays in the dynamic evolution of a Z-pinch and demonstrate the need for as near a self-consistent radiation-hydrodynamics treatment as possible

  8. Linear No-Threshold Model VS. Radiation Hormesis

    OpenAIRE

    Doss, Mohan

    2013-01-01

    The atomic bomb survivor cancer mortality data have been used in the past to justify the use of the linear no-threshold (LNT) model for estimating the carcinogenic effects of low dose radiation. An analysis of the recently updated atomic bomb survivor cancer mortality dose-response data shows that the data no longer support the LNT model but are consistent with a radiation hormesis model when a correction is applied for a likely bias in the baseline cancer mortality rate. If the validity of t...

  9. A Minimal Model of Majoronic Dark Radiation and Dark Matter

    OpenAIRE

    Chang, We-fu; Ng, John N.

    2014-01-01

    We extend the singlet Majoron model of dark radiation by adding another singlet scalar of unit lepton charge. The spontaneous breaking of global $U(1)_L$ connects dark radiation with neutrino mass generation via the type-I seesaw mechanism. The model naturally has a stable scalar dark matter field. It also predicts the existence of a light scalar of mass less than 1 GeV that mixes with the Standard Model Higgs boson. We perform a numerical analysis of the parameters of the m...

  10. MCNP model for the many KE-Basin radiation sources

    Energy Technology Data Exchange (ETDEWEB)

    Rittmann, P.D.

    1997-05-21

    This document presents a model for the location and strength of radiation sources in the accessible areas of KE-Basin which agrees well with data taken on a regular grid in September of 1996. This modelling work was requested to support dose rate reduction efforts in KE-Basin. Anticipated fuel removal activities require lower dose rates to minimize annual dose to workers. With this model, the effects of component cleanup or removal can be estimated in advance to evaluate their effectiveness. In addition, the sources contributing most to the radiation fields in a given location can be identified and dealt with.

  11. MCNP model for the many KE-Basin radiation sources

    International Nuclear Information System (INIS)

    This document presents a model for the location and strength of radiation sources in the accessible areas of KE-Basin which agrees well with data taken on a regular grid in September of 1996. This modelling work was requested to support dose rate reduction efforts in KE-Basin. Anticipated fuel removal activities require lower dose rates to minimize annual dose to workers. With this model, the effects of component cleanup or removal can be estimated in advance to evaluate their effectiveness. In addition, the sources contributing most to the radiation fields in a given location can be identified and dealt with

  12. Modelling radiation damage to ESA's Gaia satellite CCDs

    OpenAIRE

    Seabroke, George; Holland, Andrew; Cropper, Mark

    2008-01-01

    The Gaia satellite is a high-precision astrometry, photometry and spectroscopic ESA cornerstone mission, currently scheduled for launch in late 2011. Its primary science drivers are the composition, formation and evolution of the Galaxy. Gaia will not achieve its scientific requirements without detailed calibration and correction for radiation damage. Microscopic models of Gaia's CCDs are being developed to simulate the effect of radiation damage, charge trapping, which causes charge transfer...

  13. Minimal Radiative Neutrino Mass Mechanism for Inverse Seesaw Models

    CERN Document Server

    Dev, P S Bhupal

    2012-01-01

    We study a minimal one-loop radiative mechanism for generating small Majorana neutrino masses in inverse seesaw extensions of the Standard Model with two singlet fermions per family. The new feature of this radiative mechanism is that the one-loop induced left-handed neutrino mass matrix is directly proportional to the Majorana mass matrix of the right-handed neutrinos. This is a very economical scenario without necessitating the existence of non-standard scalar or gauge fields.

  14. Scattering in infrared radiative transfer: A comparison between the spectrally averaging model JURASSIC and the line-by-line model KOPRA

    International Nuclear Information System (INIS)

    The viability of a spectrally averaging model to perform radiative transfer calculations in the infrared including scattering by atmospheric particles is examined for the application of infrared limb remote sensing measurements. Here we focus on the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) aboard the European Space Agency's Envisat. Various spectra for clear air and cloudy conditions were simulated with a spectrally averaging radiative transfer model and a line-by-line radiative transfer model for three atmospheric window regions (825–830, 946–951, 1224–1228 cm?1) and compared to each other. The results are rated in terms of the MIPAS noise equivalent spectral radiance (NESR). The clear air simulations generally agree within one NESR. The cloud simulations neglecting the scattering source term agree within two NESR. The differences between the cloud simulations including the scattering source term are generally below three and always below four NESR. We conclude that the spectrally averaging approach is well suited for fast and accurate infrared radiative transfer simulations including scattering by clouds. We found that the main source for the differences between the cloud simulations of both models is the cloud edge sampling. Furthermore we reasoned that this model comparison for clouds is also valid for atmospheric aerosol in general. -- Highlights: •We simulate atmospheric radiative transfer in the infrared. •The simulations include single scattering on cloud particles. •We compare the results of a line-by-line model with a spectrally averaging model. •For clear air as well as cloudy conditions both models agree well. •We found that the most crucial aspect of the simulations is the cloud sampling

  15. Quasi-steady-state model of a counter flow air-to-air heat exchanger with phase change

    DEFF Research Database (Denmark)

    Rose, JØrgen; Nielsen, Toke Rammer

    2008-01-01

    Using mechanical ventilation with highly efficient heat-recovery in northern European or arctic climates is a very efficient way of reducing the energy use for heating in buildings. However, it also presents a series of problems concerning condensation and frost formation in the heat-exchanger. Developing highly efficient heat-exchangers and strategies to avoid/remove frost formation implies the use of detailed models to predict and evaluate different heat-exchanger designs and strategies. This paper presents a quasi-steady-state model of a counter-flow air-to-air heat-exchanger that takes into account the effects of condensation and frost formation. The model is developed as an Excel spreadsheet, and specific results are compared with laboratory measurements. As an example, the model is used to determine the most energy-efficient control strategy for a specific heat-exchanger under northern European and arctic climate conditions. (C) 2007 Elsevier Ltd. All rights reserved.

  16. Existing air sparging model and literature review for the development of an air sparging optimization decision tool

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-08-01

    The objectives of this Report are two-fold: (1) to provide overviews of the state-of-the-art and state-of-the-practice with respect to air sparging technology, air sparging models and related or augmentation technologies (e.g., soil vapor extraction); and (2) to provide the basis for the development of the conceptual Decision Tool. The Project Team conducted an exhaustive review of available literature. The complete listing of the documents, numbering several hundred and reviewed as a part of this task, is included in Appendix A. Even with the large amount of material written regarding the development and application of air sparging, there still are significant gaps in the technical community`s understanding of the remediation technology. The results of the literature review are provided in Section 2. In Section 3, an overview of seventeen conceptual, theoretical, mathematical and empirical models is presented. Detailed descriptions of each of the models reviewed is provided in Appendix B. Included in Appendix D is a copy of the questionnaire used to compile information about the models. The remaining sections of the document reflect the analysis and synthesis of the information gleaned during the literature and model reviews. The results of these efforts provide the basis for development of the decision tree and conceptual decision tool for determining applicability and optimization of air sparging. The preliminary decision tree and accompanying information provided in Section 6 describe a three-tiered approach for determining air sparging applicability: comparison with established scenarios; calculation of conceptual design parameters; and the conducting of pilot-scale studies to confirm applicability. The final two sections of this document provide listings of the key success factors which will be used for evaluating the utility of the Decision Tool and descriptions of potential applications for Decision Tool use.

  17. Mechanistic models for cancer development after short time radiation exposure

    International Nuclear Information System (INIS)

    In this work two biological based models were developed. First the single-hit model for solid tumors (SHM-S) and second the single-hit model for leukemia (SHM-L). These models are a further development of the Armitage-Doll model for the special case of a short time radiation exposure. The basis of the models is the multistage process of carcinogeneses. The single-hit models provide simultaneously the age-dependent cancer-rate of spontaneous and radiation induced tumors as well as the dose-effect relationships at any age after exposure. The SHM-S leads to a biological based dose-effect relationship, which is similar to the relative risk model suggested by the ICRP 60. The SHM-S describes the increased mortality rate of the bomb survivors more accurate than the relative risk model. The SHM-L results in an additive dose-effect relationship. It is shown that only small differences in the derivation of the two models lead to the two dose-effect relationships. Beside the radiation exposure the new models consider the decrease of the cancer mortality rate at higher ages (age>75) which can be traced back mainly to three causes: competitive causes of death, reduction of cell proliferation and reduction of risk groups. The single-hit models also consider children cancer, the different rates of incidence and mortality, influence of the immune system and the cell-killing effect. (author)

  18. Model-independent radiative corrections to ?-??+K- decay

    International Nuclear Information System (INIS)

    We follow Sirlin's procedure to compute the radiative corrections to the decay ?-??+K-. We work up to first order in the fine structure constant ? and split these corrections into model-independent and model-dependent parts. The former is calculated explicitly and the latter is shown to be absorbed into the so-called decay amplitudes or form factors.

  19. GASPAR-II, Radiation Exposure to Man from Air Releases of Reactor Effluents

    International Nuclear Information System (INIS)

    1 - Description of program or function: GASPAR implements the air release dose models of the NRC Regulatory Guide 1.109 for noble gases (semi-infinite plume only) and the radioiodine and particulate emissions. GASPAR computes both population (ALARA-As Low As Reasonably Achievable and NEPA-National Environmental Policy Act) and individual doses. Site data, meteorological data, radionuclide release source terms, and location meteorological data for selected individuals are specified as input data. The site data includes population data and milk, meat, and vegetation production. The meteorological data includes dispersion X/Q, X/Q decayed, X/Q decayed and depleted, and deposition. Population doses, individual doses, and cost benefit tables are calculated. 2 - Method of solution: There are two basic types of calculations, the population dose calculation and the individual dose calculation; however, both may be combined in a single GASPAR execution. There are usually several source terms corresponding to several release points. As the dose is computed for each source term it is accumulated so that the dose printed for the first source term is the actual dose for that term. For all subsequent source terms the dose printed is the accumulated dose with the dose printed for the last source term, the grand total for the problem. For the cost benefit table, individual source term doses are generated. Seven pathways by which the nuclides travel to man are considered. These are pltravel to man are considered. These are plume, ground, inhalation, vegetation, cows' milk, goats' milk, and meat. For the individual dose calculations, man is subdivided into the four age groups of infant (0 to 1 year), child (1-11 years), teenager (12-18 years) and adult (over 18 years). Each of these calculations take into account eight body organs - T. body, G.I. track, bone, liver, kidney, thyroid, lung, and skin. 3 - Restrictions on the complexity of the problem: None noted

  20. Analytical approach to the modeling of radiation effects in tissue

    International Nuclear Information System (INIS)

    This paper reports the application of reactor physics calculational methods to the analysis of the interaction of radiation with tissue with the objective of developing a radiation effects model that is equivalent to the reactor point kinetics equations in mathematical rigor and utility. A primary motivation for this effort is that concerns about exposure to low levels of radiation have caused enormous expense to the nuclear industry in terms of both lack of public acceptance and regulation of activities involving minor amounts of radioactivity. These concerns might be alleviated if there were a rigorous yet mathematically tractable model of the effects of radiation on tissue. Our understanding of such effects is derived by extrapolation from high-level exposures. These extrapolations involve statistical considerations that are not readily understood by the public. Regulators also have difficulty in that existing mathematical models of the biological effects of radiation do little to promote understanding by the nonspecialist. There are two approaches. At one extreme are simple calculational methods that combine the definition of dose with information on the range of the radiation. For example, for charged particles, all of the energy is deposited locally