WorldWideScience
 
 
1

Developing of a New Atmospheric Ionizing Radiation (AIR) Model  

Science.gov (United States)

As a result of the research leading to the 1998 AIR workshop and the subsequent analysis, the neutron issues posed by Foelsche et al. and further analyzed by Hajnal have been adequately resolved. We are now engaged in developing a new atmospheric ionizing radiation (AIR) model for use in epidemiological studies and air transportation safety assessment. A team was formed to examine a promising code using the basic FLUKA software but with modifications to allow multiple charged ion breakup effects. A limited dataset of the ER-2 measurements and other cosmic ray data will be used to evaluate the use of this code.

Clem, John M.; deAngelis, Giovanni; Goldhagen, Paul; Wilson, John W.

2003-01-01

2

Macroscopic Model of Geomagnetic-Radiation from Air Showers, II  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The generic properties of the emission of coherent radiation from a moving charge distribution are discussed. The general structure of the charge and current distributions in an extensive air shower are derived. These are subsequently used to develop a very intuitive picture for the properties of the emitted radio pulse. Using this picture can be seen that the structure of the pulse is a direct reflection of the shower profile. At higher frequencies the emission is suppresse...

Scholten, Olaf; Vries, Krijn D.; Werner, Klaus

2010-01-01

3

Experimental study and improved modeling of high-temperature air radiation  

Science.gov (United States)

Spectral emission measurements were conducted in an atmospheric pressure air plasma. The thermodynamic state of the plasma was determined to be close to local thermodynamic equilibrium (LTE), and the temperature profile was measured. The spectrum emitted by the plasma over the range 2,000 to 8,000 A was recorded and calibrated. This spectrum comprises the major radiating molecular bands and atomic lines in air, and is therefore proposed as a benchmark to test radiative calculations. A comparison of these results with the predictions of the NEQAIR code induced several modeling improvements in the code. In particular, radiative transition probabilities and spectroscopic constants were updated, and additional band systems of NO (NO Delta, Epsilon, Beta prime and Gamma prime) were included. Since the C state from which the NO Delta transition originates is predissociated, a simplified collision-predissociation model for this state was added to the code. These changes are presented, and their effect discussed.

Laux, Christophe O.; Moreau, Stephane; Kruger, Charles H.

1992-01-01

4

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

5

Numerical Modelling of Air Streamer Discharge Radiation in the Second Positive and First Negative Systems of Molecular Nitrogen  

International Nuclear Information System (INIS)

Numerical modelling of radiation pulses of an air streamer discharge in the second positive and first negative systems of molecular nitrogen is performed, accounting for non-stationary processes of population and depopulation of the excited states. Temporal characteristics of radiation pulses are obtained in dependence upon a streamer intensity and spatial resolution of a spectral optical system. It is shown that spectral diagnostic methods based on steady state approximations are inapplicable to non-stationary and non-equilibrium streamer plasma. (author)

6

Air crew radiation exposure measurements  

International Nuclear Information System (INIS)

A research project to investigate the exposure of air crew to cosmic radiation in flight altitudes was carried out between 1997 and 1999. Because of the complexity of the radiation field and the huge energy range of the particles involved, tissue-equivalent proportional counters (TEPC) were used as reference instruments to measure the ambient dose equivalent rate. Various other instruments for radiation protection dosimetry could be calibrated against the TEPC in the cosmic radiation field at flight altitudes. It was found that the sum of a high-pressure ionization chamber and a rem counter can be used to determine the dose equivalent rate in aircraft with an uncertainty of less than 10% supposed that for the rem counter the proper calibration factor has been used. The results of the global dose equivalent rate monitoring are reported and concepts for the practical radiation protection work are discussed. (orig.)

7

Attenuation model of radiations in air close to tritium contaminated surfaces  

International Nuclear Information System (INIS)

In this paper we present a calculation model which establishes a relationship between the number of tritium atoms contaminating a surface and the counting rate in detector. The model depends on separation between detector and contaminated surface and may be applied to a PIN diode of Hamamatsu type series 1223. The model tries to take into account all possible factors that can contribute to the counting rate of the detector. Different detection geometries are considered. (authors)

8

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)

9

Influence of the Vibrational Dissociation Model on the Relaxation of the Excited States Calculated with the CORIA's Collisional-Radiative Model CoRaM-Air  

Science.gov (United States)

In relation with the problem of space vehicles re-entry into the earth atmosphere, we have developed a nonlin- ear electronic and vibrational specific time-dependent Collisional-Radiative (CR) model for air plasma working between 100 Pa and atmospheric pressure and between 2000 K and 20000 K for the translation temperatures. 13 species are considered: N2 , O2 , NO, N, O, Ar, N+ , 2 O+ , NO+ , N+ , O+ , Ar+ and electrons. This model takes 2 into account a total of 335 different states separated in excited electronic states and vibrational states of N2 , O2 and NO on their electronic ground state. Owing to the temperature levels involved, many elementary processes are considered. The CR model is partially validated by comparison with experimental results under atmospheric pressure. Time scales to reach the final steady state are derived. Two models of dissociation are tested with respect to the vibration- translation transfers. The excita- tion and vibrational temperature results are analyzed in a typicalHeaviside-like case at constant pressure and temperature.

Bultel, A.; Annaloro, J.; Schneider, I. F.; Benredjen, D.

2011-08-01

10

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

11

Nonequilibrium air radiation (Nequair) program: User's manual  

Science.gov (United States)

A supplement to the data relating to the calculation of nonequilibrium radiation in flight regimes of aeroassisted orbital transfer vehicles contains the listings of the computer code NEQAIR (Nonequilibrium Air Radiation), its primary input data, and explanation of the user-supplied input variables. The user-supplied input variables are the thermodynamic variables of air at a given point, i.e., number densities of various chemical species, translational temperatures of heavy particles and electrons, and vibrational temperature. These thermodynamic variables do not necessarily have to be in thermodynamic equilibrium. The code calculates emission and absorption characteristics of air under these given conditions.

Park, C.

1985-07-01

12

Monitoring radiation doses received by air crews  

Science.gov (United States)

Since 2000, Air Transport Companies in Europe have the legal obligation to monitor radiation doses received by each air crew member. The French Aviation Authorities have developed a system called SIEVERT, using effective dose calculation codes and neutron monitor observations. We present this typical Space Weather application and discuss the solution retained in the frame of this system to monitor galactic cosmic rays and GLE's, and corresponding doses.

Lantos, P.; Fuller, N.; Bottollier-Depois, J.-F.

2001-08-01

13

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

Science.gov (United States)

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

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

2013-01-01

14

Transport of initial radiations in air over ground  

International Nuclear Information System (INIS)

A time-dependent system of classification is normally used to divide the ionizing radiation from a nuclear explosion into two groups: initial and residual. The initial radiation is the ionizing radiation emitted within the first minute following the detonation of the weapon, and the residual radiation is the ionizing radiation emitted later. Transport calculations for the prompt and delayed radiations were performed separately and then combined at fixed ground locations to obtain the total neutron and gamma-ray fluence, together with their energy and angular distributions. Modeling of the air-over-ground transport for the delayed radiation is a more difficult task. For example, such complex effects as the rapid early-time decay of the fission products, the rise of the fireball, and the blast-enhanced transport of the delayed radiation must be considered. The blast wave from the explosion enhances the transport of the delayed radiations by removing most of the air between the fireball and the shock front. This work uses transport modeling procedures and source term data developed in studies by Science Applications International Corporation (SAIC). In their studies, the delayed neutron and gamma-ray fluences were estimated by means of a one-dimensional ANISN calculation that takes into account the air density profile at a fixed location on the ground at discrete time intervals after the explosion. The effects of ground scattering were then computed separately by means og were then computed separately by means of the VCS code. These transport modeling procedures were verified by applying them to weapon tests where time dependent gamma-ray measurements were made as a function of ground range. Many of the calculations and comparisons of this work involve the use of dosimetric parameter called kerma. Kerma equals the total kinetic energy of all the charged particles liberated by neutrons and gamma rays in a small volume of a given material divided by the mass of the material in that volume element

15

Sensitivity of contrail cirrus radiative forcing to air traffic scheduling  

Science.gov (United States)

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.

Newinger, Christina; Burkhardt, Ulrike

2012-05-01

16

Radiation control at open-air sediment fixation facility  

International Nuclear Information System (INIS)

For disposal of radioactive wastes at NPP A-1 it was necessary to built special facilities for their treatment. One of them is a facility for sediment fixation by its cementation that was designed and constructed by VUJE a.s. in 2004 -2005. A 3D model of this facility is shown. Except of technological parts of the facility , the system of radiation control plays an important role, too. Range of the radiation control system fulfils demands of the valid legislative documents, the technical design of the technology sediment fixation and the present state of objects VYZ Jaslovske Bohunice. The radiation control system has been designed for monitoring of radiological situation during normal operation as well as during radiation accidents. System of radiation control at fixation facility covers: (1) personnel radiation control; (2) radiation control of working area (semi servicing areas); (3) radiation control of gaseous releases; (4) radiation control of the facility technology, monitoring of the vicinity of the open-air facility; (5) informational system of radiation control. (authors)

17

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)

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.

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

1976-01-01

18

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)

19

Investigation of infra-red and nonequilibrium air radiation  

Science.gov (United States)

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

Kruger, Charles H.

1995-01-01

20

Solar radiation models - review  

Directory of Open Access Journals (Sweden)

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.

M. Jamil Ahmad, G.N. Tiwari

2010-05-01

 
 
 
 
21

Blackbody Radiation Spectrum Model  

Science.gov (United States)

The Blackbody Radiation Spectrum model shows six fixed-temperature curves between Tmin and Tmax and a red variable-temperature curve that can be adjusted using a slider. The wavelength is measured in nm (nanometer) and the intensity is measured in W.e-5 / (m2.nm). Users can adjust Tmin and Tmax to change the temperature range that is displayed. The Blackbody Radiation Spectrum was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double click the ejs_ntnu_BlackbodyRadiationSpectrum.jar file to run the program if Java is installed.

Hwang, Fu-Kwun

2009-08-22

22

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  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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. In contrast to previous comparison exercises, box-air-mass-factors (box-AMFs) for various 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...

Wagner, T.; Burrows, J. P.; Deutschmann, T.; Dix, B.; Von Friedeburg, C.; Frieß, U.; Hendrick, F.; Heue, K. -p; Irie, H.; Iwabuchi, H.; Kanaya, Y.; Keller, J.; Mclinden, C. A.; Oetjen, H.; Palazzi, E.

2006-01-01

23

New radiation limits and air crew exposure  

International Nuclear Information System (INIS)

Commercial aircraft have optimum cruising speed of 800 - 900 km/h and the cruising altitude near 13 km.The flight paths are assigned according to airway corridors and safety requirements.The relatively high dose-equivalent rates at cruising altitudes near 13 km (about 0.5-2 mSv/h, and the shielding effect of the atmosphere corresponds to about 2 M of water) can cause exposures greater than 5 mSv/y, for a crew with full-time flight (500-600 h/y).The radiation exposure of the crew in commercial air traffic has been studied for the associations of the crews and airline management and published, and regulatory authorities are slowly accepting the fact that there indeed is a problem which needs investigations and protective regulation

24

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.

25

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)

26

Regolith Radiative Transfer Model  

Science.gov (United States)

We are developing an improved regolith radiative transfer model (RRT) for multiple applications in planetary systems. Our immediate motivation for developing this particular RRT model is new data from Cassini at long IR wavelengths (100-500 microns). The first application will be to simulate the emissivity of the ring's grainy regoliths at far infrared wavelengths. The behavior of the emissivity at far IR is an important probe for determining the composition of the non-icy components of ring material.

Vahidinia, Sanaz

2006-09-01

27

Office of radiation and indoor air: Program description  

Energy Technology Data Exchange (ETDEWEB)

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.

1993-06-01

28

Frontiers in air quality modelling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Colette, A.; Bessagnet, B.; Meleux, F.; Roui?l, L.

2013-01-01

29

Assessment of cosmic radiation doses received by air crew  

International Nuclear Information System (INIS)

The radiation environment in the atmosphere at altitudes used in civil aviation is a result of the interactions of the primary cosmic radiation with the magnetosphere and the atmosphere of the earth. Because of these interactions, the intensity and composition of the radiation field varies both with altitude and wih latitude. There are also changes resulting from variations in the solar component of the cosmic radiation. Clearly the occupational exposure of air crew to cosmic radiation results in doses which may not be negligible for the point of view of radiation protection. The higher the flight altitudes and the longer the exposure, the greater will be the doses involved. (author). 6 figs

30

Frontiers in air quality modelling  

Directory of Open Access Journals (Sweden)

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.

A. Colette

2013-08-01

31

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

Science.gov (United States)

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

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

2006-06-15

32

Air quality dispersion models from energy sources  

International Nuclear Information System (INIS)

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

33

Coherent Cherenkov Radiation from Cosmic-Ray-Induced Air Showers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Very energetic cosmic rays entering the atmosphere of the Earth will create a plasma cloud moving with almost the speed of light. The magnetic field of the 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: due to 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 emis...

Vries, K. D.; Berg, A. M. Den; Scholten, O.; Werner, K.

2011-01-01

34

Modelling radiation spectrum of a discharge with two liquid non-metallic (tap-water) electrodes in air at atmospheric pressure  

International Nuclear Information System (INIS)

The emission spectra of a column of a direct-current discharge in open air which is performed between two tap-water electrodes (two tap-water flows) are studied in the 240-450 nm spectral range. A comparison of the values of spectral emissivities is made between experimental spectra and the calculated spectra. The emission spectrum calculation is made for four molecules, N2, O2, NO and OH that are present in air plasma. The first part of this paper focuses on building the spectra calculation; the required data are detailed. In the second part, rotational, vibrational and excitational temperatures are determined with the Boltzmann distribution assumed on the quantum states. For that purpose, a comparison of the modelled spectra and the experimental spectra is made in the different parts of the discharge column.

35

Radiation exposure due to cosmic radiation during air plane flights; Strahlenexposition durch Hoehenstrahlung beim Fliegen  

Energy Technology Data Exchange (ETDEWEB)

During air plane flight in high heights the people are increasingly exposed to cosmic radiation. Pilots and passengers are therefore occupational groups with the highest annual radiation dose. Due to the flight planning young air hostesses are commonly exposed to higher doses than middle aged stewardesses. Young pilots are usually exposed to lower annual doses, since they are usually fly within Europe, at lower flight heights and thus less cosmic radiation exposure.

Frasch, Gerhard [Bundesamt fuer Strahlenschutz, Oberschleissheim/Neuherberg (Germany). Beruflicher Strahlenschutz/Strahlenschutzregister

2012-07-01

36

Assessment of cosmic radiation doses received by air crew  

International Nuclear Information System (INIS)

Cosmic radiation in the atmosphere is such a complex mixture of radiation type that it is difficult to get a single instrument which is suitable for such measurements. Passive devices such as film badges and track etch detectors have also been used, but again present difficulties of interpretation and requirements of multiple devices to accommodate the different types of radiation encountered. In summary, air crew are the occupational group most highly exposed to radiation. The radiation doses experienced by them are sufficiently high as to require assessment on a regular basis and possible control by appropriate rostering. There appears little possibility of the dose limit for workers being exceeded, except possibly in the case of pregnant female crew. This category of air crew should be the subject of special controls aimed at ensuring that the dose limits for the foetus should not be exceeded

37

Coherent Cherenkov radiation from cosmic-ray-induced air showers.  

Science.gov (United States)

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. PMID:21902308

de Vries, K D; van den Berg, A M; Scholten, O; Werner, K

2011-08-01

38

Passive radiative cooling below ambient air temperature under direct sunlight.  

Science.gov (United States)

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

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

2014-11-26

39

Air Temperature estimation from Land Surface temperature and solar Radiation parameters  

Science.gov (United States)

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.

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

2013-04-01

40

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.)

 
 
 
 
41

Stochastic Modeling of Traffic Air Pollution  

DEFF Research Database (Denmark)

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.

Thoft-Christensen, Palle

2014-01-01

42

Nonequilibrium radiation of the shock wave in air in the vacuum ultraviolet region  

Science.gov (United States)

A numerical model of generation of the nonequilibrium molecular radiation in a vacuum ultraviolet spectral region (VUV radiation with a wavelength shorter than 200 nm) behind a shock wave in air in a range of varying its velocity of 4.5-9.5 km/s is developed. This numerical model is verified using the results of experiments in a shock tube for studying the photoionization effect before the shock-wave front in a wave-length range of 85-105 nm. Some features of nonequilibrium VUV radiation, particularly its generation a very thin high-temperature layer behind the shock-wave front, are established.

Gorelov, V. A.; Kireev, A. Yu.

2013-01-01

43

Air travel and radiation risks - review of current knowledge  

International Nuclear Information System (INIS)

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

44

Modelling of radio emission from cosmic ray air showers  

Science.gov (United States)

Cosmic rays entering the Earth's atmosphere induce extensive air showers consisting of up to billions of secondary particles. Among them, a multitude of electrons and positrons are generated. These get deflected in the Earth's magnetic field, creating time-varying transverse currents. Thereby, the air shower emits coherent radiation in the MHz frequency range measured by radio antenna arrays on the ground such as LOPES at the KIT. This detection method provides a possibility to study cosmic rays with energies above 1017 eV. At this time, the radio technique undergoes the change from prototype experiments to large scale application. Thus, a detailed understanding of the radio emission process is needed more than ever. Before starting this work, different models made conflicting predictions on the pulse shape and the amplitude of the radio signal. It turned out that a radiation component caused by the variation of the number of charged particles within the air shower was missed in several models. The Monte Carlo code REAS2 superposing the radiation of the individual air shower electrons and positrons was one of those. At this time, it was not known how to take the missing component into account. For REAS3, we developed and implemented the endpoint formalism, a universal approach, to calculate the radiation from each single particle. For the first time, we achieve a good agreement between REAS3 and MGMR, an independent and completely different simulation approach. In contrast to REAS3, MGMR is based on a macroscopic approach and on parametrisations of the air shower. We studied the differences in the underlying air shower models to explain the remaining deviations. For comparisons with LOPES data, we developed a new method which allows "top-down" simulations of air showers. From this, we developed an air shower selection criterion based on the number of muons measured with KASCADE to take shower-to-shower fluctuations for a single event analysis into account. With this method, we simulate for the first time the radio emission from an air shower directly comparable with the measured one. We validated with a comparison between REAS3 simulations and LOPES data that the understanding of the radio emission from air showers increased significantly. REAS3 is the first simulation predicting lateral slope parameters and electric fields as measured with LOPES without using any free parameters. Last but not least, we show the didactic quality of the endpoint formalism. This formalism can be used to calculate any radiation from accelerated charged particles, which allows an increased insight in the radiation phenomena of classical electrodynamics. Thus, the endpoint formalism provides a universal tool which is relevant for scientists in many different fields.

Ludwig, Marianne

2011-06-01

45

Two Dimensional Air Drop Model  

Science.gov (United States)

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.

Franciscouembre

2014-06-12

46

Is cosmic radiation exposure of air crew amenable to control?  

International Nuclear Information System (INIS)

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

47

Air pollution model for point source  

Directory of Open Access Journals (Sweden)

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

Jozef Ma?ala

2006-12-01

48

Air pollution model for point source  

International Nuclear Information System (INIS)

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

49

Air pollution model for point source  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Jozef Ma?ala; Viliam Carach

2006-01-01

50

Preclinical models in radiation oncology  

Directory of Open Access Journals (Sweden)

Full Text Available 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 employed in the discovery of molecular targets for tumor radiosensitization. Ultimately, any model system must be judged by its utility in developing more effective cancer therapies, which is in turn dependent on its ability to simulate the biology of tumors as they exist in situ. Although every model has its limitations, each has played a significant role in preclinical testing. Continued advances in preclinical models will allow for the identification and application of targets for radiation in the clinic.

Kahn Jenna

2012-12-01

51

Air Quality Response Modeling for Decision Support  

Science.gov (United States)

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 emis...

52

AIR QUALITY MODEL EVALUATION - FORECASTING AND RETROSPECTIVES  

Science.gov (United States)

This presentation discusses the CMAQ model evaluation framework, and presents results of evaluation of CMAQ's particulate matter estimates for PM2.5, and its components for 2005 air quality forecast predictions as well as retrospective modeling for 2001....

53

Radiative fluxes in the troposphere from upper air meteorological data in Saudi Arabia  

Energy Technology Data Exchange (ETDEWEB)

An attempt is made to use the empirical type of parameterization scheme for the calculations of solar radiative fluxes and atmospheric heating or cooling rates in the troposphere by using observed upper air meteorological data. This type of parameterization scheme is useful in calculating the upper air heating/cooling rate for use in planetary boundary layer modeling and in the evaluation of the surface heat budget equation. The results presented in this paper are based on the upper air data collected between 1300 to 1500 Local Standard Time (LST) in Dhahran for the year 1989. The diurnal variation of vertical profiles of radiative fluxes and heating/cooling rates is calculated by changing the solar zenith angle. The diurnal variation of annually averaged solar radiation fluxes reaching the ground is compared with the observed values of solar radiative flux at Dhahran. The calculated values are in excellent agreement with the observed values in the morning and evening times. The scheme used in this paper can be used for obtaining solar radiative fluxes and atmospheric heating or cooling rates above the earth's surface at places where only upper air meteorological data is available.

Rehman, S.; Husain, T.; Halawani, T.O. (King Fahd Univ. of Petroleum and Minerals, Dhahran (Saudi Arabia))

1992-07-01

54

Ab Initio Modeling of Molecular Radiation  

Science.gov (United States)

Radiative emission from excited states of atoms and molecules can comprise a significant fraction of the total heat flux experienced by spacecraft during atmospheric entry at hypersonic speeds. For spacecraft with ablating heat shields, some of this radiative flux can be absorbed by molecular constituents in the boundary layer that are formed by the ablation process. Ab initio quantum mechanical calculations are carried out to predict the strengths of these emission and absorption processes. This talk will describe the methods used in these calculations using, as examples, the 4th positive emission bands of CO and the 1g+ 1u+ absorption in C3. The results of these calculations are being used as input to NASA radiation modeling codes like NeqAir, HARA and HyperRad.

Jaffe, Richard; Schwenke, David

2014-01-01

55

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

56

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

57

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

58

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

Directory of Open Access Journals (Sweden)

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.

Supawan TIRAWANICHAKUL

2008-01-01

59

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)

60

Priliminary Modeling of Air Breakdown with the ICEPIC code  

CERN Document Server

Interest in air breakdown phenomena has recently been re-kindled with the advent of advanced virtual prototyping of radio frequency (RF) sources for use in high power microwave (HPM) weapons technology. Air breakdown phenomena are of interest because the formation of a plasma layer at the aperture of an RF source decreases the transmitted power to the target, and in some cases can cause significant reflection of RF radiation. Understanding the mechanisms behind the formation of such plasma layers will aid in the development of maximally effective sources. This paper begins with some of the basic theory behind air breakdown, and describes two independent approaches to modeling the formation of plasmas, the dielectric fluid model and the Particle in Cell (PIC) approach. Finally we present the results of preliminary studies in numerical modeling and simulation of breakdown.

Schulz, A E; Cartwright, K L; Mardahl, P J; Peterkin, R E; Bruner, N; Genoni, T; Hughes, T P; Welch, D

2004-01-01

 
 
 
 
61

Heating, ventilation and air conditioning system modelling  

Energy Technology Data Exchange (ETDEWEB)

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)

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

2011-03-15

62

Radiation doses arising from the air transport of radioactive materials  

International Nuclear Information System (INIS)

There is a compelling need for the transport of radioactive material by air because of the requirement by hospitals throughout the world for urgent delivery for medical purposes. Many countries have no radionuclide-producing capabilities and depend on imports: a range of such products is supplied from the United Kingdom. Many of these are short lived, which explains the need for urgent delivery. The only satisfactory method of delivery on a particular day to a particular destination is often by the use of scheduled passenger air service. The International Civil Aviation Organization's Technical Instructions for the Safe Transport of Dangerous Goods by Air (ICAO 1987-1988), prescribe the detailed requirements applicable to the international transport of dangerous goods by air. Radioactive materials are required to be separated from persons and from undeveloped photographic films or plates: minimum distances as a function of the total sum of transport indexes are given in the Instructions. A study, which included the measurement and assessment of the radiation doses resulting from the transport of radioactive materials by air from the UK, has been performed by the National Radiological Protection Board (NRPB) on behalf of the Civil Aviation Authority (CAA) and the Department of Transport (DTp)

63

Impact of Asian Dust on Global Surface Air Quality and Radiation Budget  

Science.gov (United States)

Dust originating from Asian deserts and desertification areas can be transported regionally and globally to affect surface air quality, visibility, and radiation budget not only at immediate downwind locations (e.g., eastern Asia) but also regions far away from the sources (e.g., North America). Deposition of Asian dust to the North Pacific Ocean basin influences the ocean productivity. In this study, we will use the Goddard Chemistry Aerosol Radiation and Transport (GOCART) model, remote sensing data form satellite and from the ground-based network, and in-situ data from aircraft and surface observations to address the following questions: - What are the effects of Asian dust on the surface air quality and visibility over Asia and North America? - What are the seasonal and spatial variations of dust deposition to the North Pacific Ocean? How does the Asian dust affect surface radiation budget?

Chin, Mian; Diehl, Thomas; Yu, Hongbin; Ginoux, Paul

2006-01-01

64

Surface Flux Modeling for Air Quality Applications  

Directory of Open Access Journals (Sweden)

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.

Limei Ran

2011-08-01

65

Effect of ionizing radiation on moist air systems  

International Nuclear Information System (INIS)

The radiation chemistry of nitrogen/oxygen/water systems is reviewed. General radiolytic effects in dry nitrogen/oxygen systems are relatively well characterized. Irradiation results in the formation of steady state concentrations of ozone, nitrous oxide and nitrogen dioxide. In closed systems, the concentration observed depends on the total dose, temperature and initial gas composition. Only three studies have been published that focus on the radiation chemistry of nitrogen/oxygen/water homogeneous gas systems. Mixed phase work that is relevant to the gaseous system is also summarized. The presence of water vapor results in the formation of nitric acid and significantly changes the chemistry observed in dry air systems. Mechanistic evidence from the studies reviewed are summarized and discussed in relation to characterizing the gas phase during the containment period of a repository in tuff

66

Mathematical Models for Room Air Distribution  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Nielsen, Peter V.

1982-01-01

67

Mathematical Models for Room Air Distribution - Addendum  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Nielsen, Peter V.

1982-01-01

68

Mathematical Models for Room Air Distribution - Addendum  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Nielsen, Peter V.

2013-01-01

69

Mathematical Models for Room Air Distribution  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Nielsen, Peter V.

2013-01-01

70

Bayesian model comparison of solar radiation models  

Energy Technology Data Exchange (ETDEWEB)

In this paper, we propose a new statistical method: the Bayesian Model Comparison (BMC) method for selecting an adequate hourly diffuse fraction correlation. Six models are investigated and compared according to the BMC method. The selection of the best model is based on a Bayesian criterion called the Deviance Information Criterion (DIC). In this article, we demonstrate the usefulness of the DIC criterion in the model selection process and we issue a caution regarding the selection of a model with standard statistical methods. The aim of this paper is also to introduce the DIC to the solar radiation modeling community. (orig.)

Lauret, Philippe; Riviere, Carine [Lab. de Physique du Batiment et des Systemes, Saint-Denis (France)

2008-07-01

71

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)

72

Adaptive Grid Use in Air Quality Modeling  

Directory of Open Access Journals (Sweden)

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.

Mehmet Talat Odman

2011-09-01

73

An air quality model for Central Mexico  

International Nuclear Information System (INIS)

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

74

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)

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.

T. Wagner

2007-01-01

75

Collimator scatter in modeling radiation beam profiles.  

Science.gov (United States)

In computer dose calculations using scatter-air ratio sector summation algorithms, the primary dose from the target to points away from the central axis of a beam is computed using an exponential intensity model of the source and a transmission parameter for the collimator. This model works well inside the beam and near edges but is inaccurate outside the beam at distances of more than 1-2 cm from beam edges. We have modified the standard beam profile model to include a dose contribution representing photon radiation scattered from the collimators. Collimator edges are treated mathematically as line sources and an adjustable parameter is introduced which represents the activity per unit length of the collimator edges. Dose from the collimator edges is assumed to decrease purely geometrically as the inverse of the square of the distance and no modification is made for tissue attenuation. With these assumptions, the total collimator scatter dose to a point is most accurately computed by a line integral over the edges of the beam outline. This modification fits naturally into the standard scatter-air ratio sector summation computer algorithm but adds significantly to dose computation time. Some approximations eliminate the line integration and lead to a collimator scatter term which is proportional to field perimeter and independent of off-axis distance. The modified dose model was tested by comparing measured dose profiles with computed ones using x-ray beams from Philips (6 and 15 MV) and Varian (4 and 6 MV) accelerators. There was significant improvement in fit compared to the standard beam model for points outside the radiation beam. PMID:2385199

Rosen, I I; Loyd, M D; Lane, R G

1990-01-01

76

Quantitative evaluating the energy field of pulsed x radiation backscattered in air  

International Nuclear Information System (INIS)

Air background (fraction of radiation, backscattered in air) taken into account when conducting measurements using the devices with operating principle based on the dependence of backscattered ?-quanta flux density reo.istered in the given time interval (strobe) on the measured parameters is evaluated. It is shown that the energy of ?-quanta backscattered in an air layer energy of pulsed x radiation background in a strobe is defined not only by initial radiation energy and collimation angle but by the strobe location on time axis in relation to the radiated pulse as well i.e. by air layer location in space

77

Slot Region Radiation Environment Models  

Science.gov (United States)

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

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

2013-04-01

78

Meteorological Processes Affecting Air Quality ? Research and Model Development Needs  

Science.gov (United States)

Meteorology modeling is an important component of air quality modeling systems that defines the physical and dynamical environment for atmospheric chemistry. The meteorology models used for air quality applications are based on numerical weather prediction models that were devel...

79

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

80

Experimental determination of isodose curves in the air for beta radiation and Bremsstrahlung  

International Nuclear Information System (INIS)

The values of absorbed radiation doses in the air were determined aiming to obtain the isodose curves, for beta radiation and for Bremsstrahlung radiation of a 85Kr source, in several distances. Mamography films and a scintillator detector were used. The method was efficient for determining the radiation field and can be used for industrial and medical sources. (E.G.)

 
 
 
 
81

Air Quality Response Modeling for Decision Support  

Directory of Open Access Journals (Sweden)

Full Text Available 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 modeling remains complicated by the challenge of validating sensitivity results against observable data. This manuscript reviews the state of the science of atmospheric response modeling as well as efforts to characterize the accuracy and uncertainty of sensitivity results.

Sergey L. Napelenok

2011-08-01

82

Air quality modeling in Warsaw Metropolitan Area  

Directory of Open Access Journals (Sweden)

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.

Piotr Holnicki

2013-04-01

83

Air quality modeling for emergency response applications  

International Nuclear Information System (INIS)

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

84

COMPUTATIONAL MODELING ISSUES IN NEXT GENERATION AIR QUALITY MODELS  

Science.gov (United States)

EPA's Atmospheric Research and Exposure Assessment Laboratory is leading a major effort to advance urban/regional multi-pollutant air quality modeling through development of a third-generation modeling system, Models-3. he Models-3 system is being developed within a high-performa...

85

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

International Nuclear Information System (INIS)

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

86

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-06-15

87

Dosimetry methods for the measurement of the radiation exposure of civil air crew  

International Nuclear Information System (INIS)

Civil air crew are exposed in the course of their work, to elevated levels of natural background radiation, namely secondary cosmic radiation of galactic and solar origin. Recent re-evaluations of the risk associated with radiation exposure in general and neutron radiation in particular, the trend towards higher cruising altitudes for sub-sonic aircraft, and proposals to include exposures in jet aircraft to natural sources of radiation as part of occupational exposure, have been factors in focusing attention on the radiation exposure of civil air crew. This paper considers the dosimetry methods available in order to assess the options for the monitoring and control of exposure. (author)

88

Assessing Climate Impacts on Air Pollution from Models and Measurements  

Science.gov (United States)

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.

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

2011-12-01

89

Radiation protection requirements on exhaust air installations of low-energy particle accelerators  

International Nuclear Information System (INIS)

During operation of accelerators the air of irradiation rooms, gets activated by neutrons. The radioactive gases and aerosols contribute to the radiation exposure of persons in the neighbourhood. Recommendations are given how emissions and therefore the radiation burden can be minimized. The recommendations are applied to the exhaust air installations of a compact-cyclotron and a mini-cyclotron. 8 figs. (Author)

90

Stochastic Modeling of Indoor Air Temperature  

Science.gov (United States)

Temperature is one of the main parameters describing thermal comfort and indoor air quality. In this paper we propose an approach, based on a modification of the continuous time random walk, to model the indoor air temperature. We perform a statistical analysis of the recorded time series, that allows us to point out the main statistical properties of the recorded variable. The obtained conclusions about the nature of the process lead to a continuous time random walk, that in contrast to the classical approach, models time dependence of the jumps distribution. Moreover, we show that the waiting times can be modeled by a tempered stable distribution, which yields a subdiffusive behavior in short times and diffusive behavior in longer times. Finally, by conducting a simulation study we illustrate possible applications of the presented approach in the thermal comfort monitoring and forecasting.

Janczura, Joanna; Maciejewska, Monika; Szczurek, Andrzej; Wy?oma?ska, Agnieszka

2013-09-01

91

A Model to Estimate Global Radiation in Complex Terrain  

Science.gov (United States)

Global radiation is an important parameter necessary for most ecological models. However, in situ data barely meets the needs of modelling mountainous ecosystems since most field stations are located in flat areas. Consequently, it is usually necessary to extrapolate radiation measurements obtained from an adjacent flat area to the complex terrain of concern. The distribution of radiation in complex terrain depends upon two factors: the local atmospheric conditions, which determine the radiation potentially available to a supposed flat surface in a given location, and the topographic effects on this possible radiation. The latter have been included in detail in most radiation models for complex terrain, but the former are often only simply treated as constant or estimated by over-simplified empirical algorithms. In this paper we propose a novel model that uses a parametric atmospheric model to calculate the potential radiation for a supposed flat surface in a given location, and then account for topographic effects. Direct radiation, diffuse radiation and reflected radiation are calculated separately in the model due to the distinctive characteristics of and the effects by topography. Based on the parametric model, this paper has investigated the relationship between radiation transmittance, clearness indices and altitude under a series of water vapour content and turbidity conditions. This combines three ratios, R b, R d, and R r, defined as the direct radiation, diffuse radiation and reflected radiation received by the arbitrary surface, respectively, to their counterparts in the horizontal surface, to estimate the global radiation for any given location. The model has been validated with data from measurements in National Park Berchtesgaden, Germany, where six measurement sites with various altitudes and topographic characteristics have been deployed. The r 2 of modelled and measured hourly global radiation are greater than 0.90 in all six sites, with RMSE varies from 16 to 100 W m-2. Sensitivity analysis revealed that the model was not sensitive to change in water vapour content, which suggests the possibility to use an exponential algorithm of water vapour content when there is no in situ water vapour content information in complex terrains. The NRMSE was only reduced by 0.04, on average, in five of the six sites when water vapour content information was calculated from the in situ air temperature and relative humidity measurements.

Wang, Quan; Tenhunen, Wang John; Schmidt, Markus; Kolcun, Olimpia

2006-05-01

92

An air spark glow phase model  

International Nuclear Information System (INIS)

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

93

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.

94

Badminton Projectile Motion: Modeling Air Resistance  

Science.gov (United States)

Badminton Projectile Motion uses the Tracker video analysis tool to analyze the motion of a badminton birdie (or shuttlecock) and then to model the motion to include air resistance. The motion of the birdie is already tracked in the video. Students compare the motion to a model of projectile motion without air resistance and then they modify it to include quadratic drag. The zip file contains the activity handout, two videos and associated Tracker files. The videos included come from the Doane College video library at http://physics.doane.edu/physicsvideolibrary/default.html#projectile and YouTube http://www.youtube.com/watch?v=NzKdQKoNbL To open the Tracker file, download and run Tracker from http://www.cabrillo.edu/~dbrown/tracker/. Tracker is free.

Cox, Anne

2012-06-22

95

ATR, Radiation Transport Models in Atmosphere at Various Altitudes  

International Nuclear Information System (INIS)

1 - Description of problem or function: ATR is a user-oriented code for calculating quickly and simply radiation environment problems at all altitudes in the atmosphere. The code is based on parametric models of a comprehensive data base of air transport results which were generated using discrete ordinates transport techniques for infinite homogeneous air. The effects of air-ground interface and non-uniform air density are treated as perturbation corrections on homogeneous air results. ATR includes parametric models for neutrons and secondary gamma rays as a function of space, energy and source- target angle out to angles of 550 g/cm2 of air. ATR contains parameterizations of infinite medium air transport of neutrons and secondary gamma rays and correction factors for the air-ground interface and high altitude exponential air. It responds to a series of user-oriented commands which specify the source, geometry and print options to output a variety of useful air transport information, including energy-angle dependent fluence, dose, current, and isodose ranges. 2 - Method of solution: The version 3 differs from earlier versions in that version 3 contains the parameterization of the new neutron and secondary gamma rays data base that was calculated using the latest DNA approved cross sections for air. Other improvements to the ATR code include: parameterization and inclusion into ATR of new air- over-ground correction factors, low energy x-rays calculations, factors, low energy x-rays calculations, new fission source, and new convenience options. 3 - Restrictions on the complexity of the problem: ATR takes approximately 36,000 decimal words of storage. This can be lessened by overlaying different parts of the code

96

Overview of atmospheric ionizing radiation (AIR) research: SST-present  

Science.gov (United States)

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 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 lowering of ICRP-recommended exposure limits (1990) 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. Published by Elsevier Ltd on behalf of COSPAR.

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

2003-01-01

97

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

98

Radiative transfer in LTE air plasmas for temperatures up to 15,000 K  

International Nuclear Information System (INIS)

Radiative transfer in local thermodynamic and chemical equilibrium N2-O2 plasmas is analyzed in this study using a line-by-line approach. The contributions of line absorption by atoms, ions and of continuous absorption by atoms, ions and molecules to the absorption coefficient of heated air are calculated. These data combined to our previous work on the contribution of molecular electronic systems to heated air radiation (J. Quant. Spectrosc. Radiat. Transfer 72 (2002) 503) lead to a reliable and exhaustive spectroscopic data base for radiative transfer in air plasmas and for temperatures up to 15,000 K. Line-by-line radiative transfer calculations are carried out for a simple planar geometry with prescribed temperature profiles. The spectral distribution of radiative fluxes and volumetric powers is analyzed and the relative contributions of continuum and line radiation are discussed

99

Natural gamma radiation in air versus soil nature in Portugal  

International Nuclear Information System (INIS)

In this work in situ gamma spectrometry is used to correlate natural gamma radiation doses to the predominant type of soils in Portugal. Natural terrestrial gamma radiation has its origin on cosmogenic and primordial nuclides (the uranium and thorium series and 40K). The importance of these nuclides in each type of soil is a consequence of soil formation from the different original rocks. Mechanical, chemical and biochemical processes determine the concentration of the primordial radionuclides present in each type of soil. Former studies of natural gamma radiation provided data on the dose rate in air 1 meter above ground for all administrative regions of Portuguese mainland and allowed the making of the radiological map of Portugal. Some of these points were selected for the present study, representing high, intermediate and low dose rate regions. The characterization of each selected point was performed by the identification of the primordial radionuclides present in the soil, their relative contribution to the dose and final evaluation of the total dose. The relative contributions of 232Th and 238U series and 40K to the dose were calculated after the analysis of the data obtained by in situ gamma spectrometry and yielded: for intrusive rocks 45 ± 7%, 25 ± 6% and 30 ± 5%, respectively for the thorium and uranium series and potassium; for sedimentary rocks 32 ± 5%, 22 ± 4% and 46 ± 5% and for metamorphic rocks 42 ± 8%, 22 ± 9% and 36 ± 13%. The relative contribution to the dose rate was determined and yielded: for intrusive rocks 67 ± 29 nGy.h-1, 37 ± 14 nGy.h-1 and 43 ± 14 nGy.h-1, respectively for the thorium and uranium series and potassium; for sedimentary rocks 12 ± 5 nGy.h-1, 8 ± 2 nGy.h-1 and 17 ± 6 nGy.h-1 and for metamorphic rocks 46 ± 36 nGy.h-1, 25 ± 20 nGy.h-1 and 31 ± 11 nGy.h-1. The ranges of the measured data and the contributions to the total dose rate for each type of soil are mentioned on the full paper. (author)

100

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)

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.

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

2014-01-20

 
 
 
 
101

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

Science.gov (United States)

...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...

2010-01-01

102

Phenomenological model of nuclear primary air showers  

Science.gov (United States)

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

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

1976-01-01

103

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

Directory of Open Access Journals (Sweden)

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.

S. Kloster

2008-11-01

104

A dispersion modelling system for urban air pollution  

Energy Technology Data Exchange (ETDEWEB)

An Urban Dispersion Modelling system UDM-FMI, developed at the Finnish Meteorological Institute is described in the report. The modelling system includes a multiple source Gaussian plume model and a meteorological pre-processing model. The dispersion model is an integrated urban scale model, taking into account of all source categories (point, line, area and volume sources). It includes a treatment of chemical transformation (for NO{sub 2}) wet and dry deposition (for SO{sub 2}) plume rise, downwash phenomena and dispersion of inert particles. The model allows also for the influence of a finite mixing height. The model structure is mainly based on the state-of-the-art methodology. The system also computes statistical parameters from the time series, which can be compared to air quality guidelines. The relevant meteorological parameters for the dispersion model are evaluated using data produced by a meteorological pre-processor. The model is based mainly on the energy budget method. Results of national investigations have been used for evaluating climate-dependent parameters. The model utilises the synoptic meteorological observations, radiation records and aerological sounding observations. The model results include the hourly time series of the relevant atmospheric turbulence 51 refs.

Karppinen, A.; Kukkonen, J.; Nordlund, G.; Rantakrans, E.; Valkama, I.

1998-10-01

105

Effects of radiation and compression on propagating spherical flames of methane/air mixtures near the lean flammability limit  

Energy Technology Data Exchange (ETDEWEB)

Large discrepancies between the laminar flame speeds and Markstein lengths measured in experiments and those predicted by simulations for ultra-lean methane/air mixtures bring a great concern for kinetic mechanism validation. In order to quantitatively explain these discrepancies, a computational study is performed for propagating spherical flames of lean methane/air mixtures in different spherical chambers using different radiation models. The emphasis is focused on the effects of radiation and compression. It is found that the spherical flame propagation speed is greatly reduced by the coupling between thermal effect (change of flame temperature or unburned gas temperature) and flow effect (inward flow of burned gas) induced by radiation and/or compression. As a result, for methane/air mixtures near the lean flammability limit, the radiation and compression cause large amounts of under-prediction of the laminar flame speeds and Markstein lengths extracted from propagating spherical flames. Since radiation and compression both exist in the experiments on ultra-lean methane/air mixtures reported in the literature, the measured laminar flame speeds and Markstein lengths are much lower than results from simulation and thus cannot be used for kinetic mechanism validation. (author)

Chen, Zheng [State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Aerospace Engineering, College of Engineering, Peking University, Beijing 100871 (China)

2010-12-15

106

PAT-2 (Plutonium Air Transportable Model 2)  

International Nuclear Information System (INIS)

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

107

Modelling, interpolation and stochastic simulation in space and time of global solar radiation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Global solar radiation data used as daily inputs for most cropping systems and water budget models are frequently available from only a few weather stations and over short periods of time. To overcome this limitation, the Campbell–Donatelli model relates daily maximum and minimum air temperatures to solar radiation. In this study, calibrated values of model site specific parameters and efficiencies of radiation estimates are reported for 29 stations in northern Italy. Their average root mea...

Bechini, L.; Ducco, G.; Donatelli, M.; Stein, A.

2000-01-01

108

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  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 exerc...

Wagner, T.; Burrows, J. P.; Deutschmann, T.; Dix, B.; Von Friedeburg, C.; Frieß, U.; Hendrick, F.; -p Heue, K.; Irie, H.; Iwabuchi, H.; Kanaya, Y.; Keller, J.; Mclinden, C. A.; Oetjen, H.; Palazzi, E.

2007-01-01

109

Biological models in epidemiology: radiation carcinogenesis  

International Nuclear Information System (INIS)

This chapter investigates the cancer risk to man from ionizing radiation with regard to 1) the relative sensitivities of various tissues to the carcinogenic effects of ionizing radiation, 2) the influence of sex, age at exposure, hormonal status and other host factors at the time of exposure, and the influence of cancer risk factors other than radiation, on the carcinogenic response to radiation, 3) the distribution over time following exposure of the excess cancer risk from radiation, and 4) the influence of various dimensions of exposure, including dose, radiation quality (linear energy transfer, or LET), and fractionation and protraction of dose. Discusses radiobiological theory and studies of the Japanese A-bomb survivors. Concludes that in the field of radiation carcinogenesis, the application of biological models to epidemiological data is successful to the extent that such models suggest simple hypotheses that are testable using the data available. Emphasizes the dependence of radiobiological theory on epidemiological observations in the study of radiation carcinogenesis

110

Experiences in evaluating regional air quality models  

Science.gov (United States)

Any area of the world concerned with the health and welfare of its people and the viability of its ecological system must eventually address the question of the control of air pollution. This is true in developed countries as well as countries that are undergoing a considerable degree of industrialization. The control or limitation of the emissions of a pollutant can be very costly. To avoid ineffective or unnecessary control, the nature of the problem must be fully understood and the relationship between source emissions and ambient concentrations must be established. Mathematical models, while admittedly containing large uncertainties, can be used to examine alternatives of emission restrictions for achieving safe ambient concentrations. The focus of this paper is to summarize our experiences with modeling regional air quality in the United States and Western Europe. The following modeling experiences have been used: future SO 2 and sulfate distributions and projected acidic deposition as related to coal development in the northern Great Plains in the U.S.; analysis of regional ozone and sulfate episodes in the northeastern U.S.; analysis of the regional ozone problem in western Europe in support of alternative emission control strategies; analysis of distributions of toxic chemicals in the Southeast Ohio River Valley in support of the design of a monitoring network human exposure. Collectively, these prior modeling analyses can be invaluable in examining a similar problem in other parts of the world as well, such as the Pacific rim in Asia.

Liu, Mei-Kao; Greenfield, Stanley M.

111

Air Pollution Data for Model Evaluation and Application  

Science.gov (United States)

One objective of designing an air pollution monitoring network is to obtain data for evaluating air quality models that are used in the air quality management process and scientific discovery.1.2 A common use is to relate emissions to air quality, including assessing ...

112

77 FR 4808 - Conference on Air Quality Modeling  

Science.gov (United States)

...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...

2012-01-31

113

The direct and inverse problems of an air-saturated poroelastic cylinder submitted to acoustic radiation  

Directory of Open Access Journals (Sweden)

Full Text Available A wave-fluid saturated poroelastic structure interaction model based on the modified Biot theory (MBT and plane-wave decomposition using orthogonal cylindrical functions is developed. The model is employed to recover from real data acquired in an anechoic chamber, the poromechanical properties of a soft cellular melamine cylinder submitted to an audible acoustic radiation. The inverse problem of acoustic diffraction is solved by constructing the objective functional given by the total square of the difference between predictions from the MBT interaction model and diffracted field data from experiment. The faculty of retrieval of the intrinsic poromechanical parameters from the diffracted acoustic fields, indicate that a wave initially propagating in a light fluid (air medium, is able to carry in the absence of mechanical excitation of the specimen, information on the macroscopic mechanical properties which depend on the microstructural and intrinsic properties of the solid phase.

Erick Ogam

2011-09-01

114

A numerical model for multigroup radiation hydrodynamics  

CERN Document Server

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...

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

2011-01-01

115

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

116

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

International Nuclear Information System (INIS)

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

117

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

International Nuclear Information System (INIS)

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

118

Mutiple simultaneous event model for radiation carcinogenesis  

International Nuclear Information System (INIS)

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

119

Combined effects of air temperature, wind, and radiation on the resting metabolism of avian raptors  

International Nuclear Information System (INIS)

American kestrels, Falco sparverius; red-tailed hawks, Buteo jamaicensis; and golden eagles, Aquila chrysaetos, were perched in a wind tunnel and subjected to various combinations of air temperature, wind, and radiation. Oxygen consumption was measured under the various combinations of environmental variables, and multiple regression equations were developed to predict resting metabolism as a function of body mass, air temperature, wind speed, and radiation load

120

The impact of micromachined ultrasonic radiators on the efficiency of transducers in air.  

Science.gov (United States)

The use of micromachined thin-film ultrasonic radiators to improve the efficiency of conventional in-air acoustic transducers is investigated. We conduct a theoretical investigation of the parameters that determine the efficiency of thin-film transducers, using a lumped parameter model, and show that the efficiency can be improved by choosing a radiating plate thickness that can be realized by micromachining. We also identified the problems that should be overcome to design and fabricate a micromachined ultrasonic transducer with the theoretically predicted efficiency. Based on the lumped parameter model, we showed that the problems can be resolved via an appropriate design scheme. A piezoelectric micromachined ultrasonic transducer is designed and fabricated to demonstrate the impact of the proposed design method. Test results for the fabricated radiator indicated that it provided an electroacoustic efficiency of 58.4%, up to 300% greater than either the unit previously fabricated by the authors or conventional unimorph ultrasonic transducers. An array of the proposed transducers was also designed, fabricated, and tested as a source transducer for a parametric array, since transducer efficiency is important for practical applications of a parametric array. The test results for the proposed transducer demonstrate its potential for improving the practicality of parametric array sources, such as parametric loudspeakers and directional ultrasonic ranging sensors. PMID:23541961

Je, Yub; Lee, Haksue; Moon, Wonkyu

2013-08-01

 
 
 
 
121

GREEN RIVER AIR QUALITY MODEL DEVELOPMENT. VALMET - A VALLEY AIR POLLUTION MODEL  

Science.gov (United States)

Following a thorough analysis of meteorological data obtained from deep valleys of western Colorado, a modular air pollution model has been developed to simulate the transport and diffusion of pollutants released from an elevated point source in a well-defined mountain valley dur...

122

AIR QUALITY MODELING FOR THE TWENTY-FIRST CENTURY  

Science.gov (United States)

This presentation describes recent and evolving advances in the science of numerical air quality simulation modeling. Emphasis is placed on new developments in particulate matter modeling and atmospheric chemistry, diagnostic modeling tools, and integrated modeling systems. New...

123

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

Directory of Open Access Journals (Sweden)

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.

S. Kloster

2008-03-01

124

Fluorescence in damp air and comments on the radiative life time  

CERN Document Server

Photon yields in damp air excited by an electron using a Sr90 $\\beta$ source are compared withthose in dry air. Water vapors considerably reduce the yields, however, a further study is needed to evaluate the effects on the energy estimation of ultrahigh-energy cosmic rays. The relation of fluorescence efficiency to the life time of de-excitation by radiation is discussed.

Sakaki, N; Nagano, M; Watanabe, Y

2005-01-01

125

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

International Nuclear Information System (INIS)

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

126

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

Science.gov (United States)

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

Mukai, Sonoyo; Nakata, Makiko

2014-01-01

127

Solving vertical transport and chemistry in air pollution models  

International Nuclear Information System (INIS)

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

128

Comparison of absorbed radiation doses in barium and air enema reduction of intussusception: a phantom study  

International Nuclear Information System (INIS)

Objective. We assessed the relative radiation load in patients undergoing hydrostatic and pneumatic reduction of childhood intussusception. Materials and methods. In a phantom study we simulated two situations occurring during reduction of intussusception. The absorbed radiation dose was measured at several positions in the phantom using either barium sulphate (BaSO4) or air in the simulated reduction, combined with either automatic exposure control (AEC) or constant exposure rate (CER) at fluoroscopy. From these values the mean absorbed dose was calculated for different depth compartments within the phantom. Results. In the barium study the mean absorbed dose averaged over the total irradiated volume was 14-23 % lower when CER was used instead of AEC; in the air study the dose was 35-43 % lower when AEC was used instead of CER. The combination of air and AEC provided the lowest mean absorbed dose in the tissue. The barium enema created a low-radiation zone, which might be utilized for protecting radiation sensitive tissue. Conclusion. The use of BaSO4 or air in reduction of intussusception requires the proper combination with CER and AEC, respectively, to minimize the radiation load to the patient; the lowest radiation load is obtained by using air and AEC. (orig.). With 1 fig., 3 tabs

129

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

Directory of Open Access Journals (Sweden)

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.

Smith Jim T

2007-04-01

130

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.

131

Economic Modeling of Compressed Air Energy Storage  

Directory of Open Access Journals (Sweden)

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.

Rui Bo

2013-04-01

132

Daily total global solar radiation modeling from several meteorological data  

Science.gov (United States)

This paper investigates the modeling of the daily total global solar radiation in Adana city of Turkey using multi-linear regression (MLR), multi-nonlinear regression (MNLR) and feed-forward artificial neural network (ANN) methods. Several daily meteorological data, i.e., measured sunshine duration, air temperature and wind speed and date of the year, i.e., monthly and daily, were used as independent variables to the MLR, MNLR and ANN models. In order to determine the relationship between the total global solar radiation and other meteorological data, and also to obtain the best independent variables, the MLR and MNLR analyses were performed with the "Stepwise" method in the Statistical Packages for the Social Sciences (SPSS) program. Thus, various models consisting of the combination of the independent variables were constructed and the best input structure was investigated. The performances of all models in the training and testing data sets were compared with the measured daily global solar radiation values. The obtained results indicated that the ANN method was better than the other methods in modeling daily total global solar radiation. For the ANN model, mean absolute error (MAE), mean absolute percentage error (MAPE), correlation coefficient ( R) and coefficient of determination ( R 2) for the training/testing data set were found to be 0.89/1.00 MJ/m2 day, 7.88/9.23%, 0.9824/0.9751, and 0.9651/0.9508, respectively.

Bilgili, Mehmet; Ozgoren, Muammer

2011-05-01

133

Modeling of air flow through a narrow crack  

International Nuclear Information System (INIS)

Radon transport in dwellings is governed to a significant extent by pressure differences and properties of transport pathways. A model of air flow through narrow cracks was created in order to facilitate prediction of air velocity and air flow. Theoretical calculations, based on numerical solution of a system of differential equations, were compared with measurements carried out on a window crack. (P.A.)

134

Estimating global solar radiation using artificial neural network and air temperature data in a semi-arid environment  

Energy Technology Data Exchange (ETDEWEB)

Global solar radiation (GSR) data are desirable for many areas of research and applications in various engineering fields. However, GSR is not as readily available as air temperature data. Artificial neural networks (ANNs) are effective tools to model nonlinear systems and require fewer inputs. The objective of this study was to test an artificial neural network (ANN) for estimating the global solar radiation (GSR) as a function of air temperature data in a semi-arid environment. The ANNs (multilayer perceptron type) were trained to estimate GSR as a function of the maximum and minimum air temperature and extraterrestrial radiation. The data used in the network training were obtained from a historical series (1994-2001) of daily climatic data collected in weather station of Ahwaz located in Khuzestan plain in the southwest of Iran. The empirical Hargreaves and Samani equation (HS) is also considered for the comparison. The HS equation calibrated by applying the same data used for neural network training. Two historical series (2002-2003) were utilized to test the network and for comparison between the ANN and calibrated HS method. The study demonstrated that modelling of daily GSR through the use of the ANN technique gave better estimates than the HS equation. RMSE and R{sup 2} for the comparison between observed and estimated GSR for the tested data using the proposed ANN model are 2.534 MJ m{sup -2} day{sup -1} and 0.889 respectively. (author)

Rahimikhoob, Ali [Irrigation and Drainage Engineering Department, College of Abouraihan, University of Tehran (Iran)

2010-09-15

135

Radiation protection: Measurement, modelling, documentation. Proceedings  

International Nuclear Information System (INIS)

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

136

Validation of spectral gas radiation models under oxyfuel conditions  

Energy Technology Data Exchange (ETDEWEB)

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.

Becher, Johann Valentin

2013-05-15

137

NCAQ panel examines uses and limitations of air quality models  

International Nuclear Information System (INIS)

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

138

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

139

Modeling activities in air traffic control systems: antecedents and consequences of a mid-air collision.  

Science.gov (United States)

In this article we present a model of some functions and activities of the Brazilian Air traffic Control System (ATS) in the period in which occurred a mid-air collision between flight GLO1907, a commercial aircraft Boeing 737-800, and flight N600XL, an executive jet EMBRAER E-145, to investigate key resilience characteristics of the ATM. Modeling in some detail activities during the collision and related them to overall behavior and antecedents that stress the organization uncover some drift into failure mechanisms that erode safety defenses provided by the Air Navigation Service Provider (ANSP), enabling a mid-air collision to be happen. PMID:22316728

de Carvalho, Paulo Victor R; Ferreira, Bemildo

2012-01-01

140

Handbook of anatomical models for radiation dosimetry  

CERN Document Server

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.

Eckerman, Keith F

2010-01-01

 
 
 
 
141

Comparison and application study on cosmic radiation dose calculation received by air crew  

International Nuclear Information System (INIS)

Objective: To facilitate evaluation on Cosmic radiation dose received by flight crew by developing a convenient and effective measuring method. Methods: In comparison with several commonly used evaluating methods, this research employs CARI-6 software issued by FAA (Federal Aviation Administration) to measure Cosmic radiation dose for flight crew members exposed to. Results: Compared with other methods, CARI-6 is capable of providing reliable calculating results on radiation dose and applicable to all flight crew of different airlines. Conclusion: Cosmic radiation received by flight crew is on the list of occupational radiation. For a smooth running of Standards for controlling exposure to cosmic radiation of air crew, CARI software may be a widely applied tool in radiation close estimation of for flight crew. (authors)

142

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

Energy Technology Data Exchange (ETDEWEB)

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 (r{sup 2} = 0.89). Electron beams were also imaged. For a fixed exposure time (100 s), air scintillation was proportional to dose rate (r{sup 2} = 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.

Fahimian, Benjamin; Türkcan, Silvan; Kapp, Daniel S.; Pratx, Guillem, E-mail: pratx@stanford.edu [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California 94305 (United States); Ceballos, Andrew [Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States)

2014-01-15

143

Determination of daily solar ultraviolet radiation using statistical models and artificial neural networks  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this study, two different methodologies are used to develop two models for estimating daily solar UV radiation. The first is based on traditional statistical techniques whereas the second is based on artificial neural network methods. Both models use daily solar global broadband radiation as the only measured input. The statistical model is derived from a relationship between the daily UV and the global clearness indices but modulated by the relative optical air mass. The inputs to the neu...

Barbero, F. J.; Lo?pez, G.; Batlles, F. J.

2006-01-01

144

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

International Nuclear Information System (INIS)

The ICRP report recommends to include air crew members among occupationally exposed persons. Many theoretical and experimental studies have been realized since 1991, and several international bodies have taken part in discussion of the topic. Most of these results are based on studies and analysis realized in the laboratory of the authors. (author). 4 refs., 2 tabs

145

On the biological significance of radiation exposure in air transport  

International Nuclear Information System (INIS)

The environmental radiation load is significantly increased at higher altitudes. Unlike terrestrial situations, there is also a sizeable fraction of densely ionising particles, mainly neutrons but also accelerated ions. This paper addresses the question of the biological significance of this radiation field in view of recent recommendations of the International Commission for Radiological Protection (ICRP). It focuses on two aspects: the dose rate dependence of mutation induction with sparsely ionising radiation and mutation induction with heavy ions. Experiments with mammalian cells in culture are summarised and their results compared with the ICRP recommendations. It is concluded that the recently introduced 'dose and dose rate effectiveness factor' has to be viewed with some caution while the new 'quality factor' seems to be essentially in line with the results of cellular investigations. (author)

146

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Chervenkov, Hristo

2013-01-01

147

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)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese 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.

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

148

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.)

149

Updating Ontario's air dispersion models : a discussion paper  

International Nuclear Information System (INIS)

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

150

AIR QUALITY SIMULATION MODEL PERFORMANCE FOR ONE-HOUR AVERAGES  

Science.gov (United States)

If a one-hour standard for sulfur dioxide were promulgated, air quality dispersion modeling in the vicinity of major point sources would be an important air quality management tool. Would currently available dispersion models be suitable for use in demonstrating attainment of suc...

151

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

Science.gov (United States)

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.

Gulati, P.; Prakash, R.; Pal, U. N.; Kumar, M.; Vyas, V.

2014-07-01

152

What is Air? A Standard Model for Combustion Simulations  

International Nuclear Information System (INIS)

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

153

FORECASTING AIR QUALITY WITH U.S. EPA'S COMMUNITY MULTISCALE AIR QUALITY (CMAQ) MODEL  

Science.gov (United States)

This project encompasses a new major application of the U.S. Environmental Protection Agency's (U.S. EPA) Community Multiscale Air Quality (CMAQ) model to real-time air quality forecasting of near-surface ozone and particulate matter (PM2.5). ...

154

Bayesian Analysis of a Reduced-Form Air Quality Model  

Science.gov (United States)

Numerical air quality models are being used for assessing emission control strategies for improving ambient pollution levels across the globe. This paper applies probabilistic modeling to evaluate the effectiveness of emission reduction scenarios aimed at lowering ground-level oz...

155

Optical observations of acoustical radiation force effects on individual air bubbles  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Previous studies dealing with contrast agent microbubbles have demonstrated that ultrasound (US) can significantly influence the movement of microbubbles. In this paper, we investigated the influence of the acoustic radiation force on individual air bubbles using high-speed photography. We emphasize the effects of the US parameters (pulse length, acoustic pressure) on different bubble patterns and their consequences on the translational motion of the bubbles. A stream of uniform air bubble...

Palanchon, Peggy; Tortoli, Piero; Bouakaz, Ayache; Versluis, Michel; Jong, Nico

2005-01-01

156

Modeling transient radiation effects in power MOSFETS  

International Nuclear Information System (INIS)

Using standard device specifications and simple assumptions, the transient radiation response of VDMOS MOSFETs can be modeled in a standard circuit analysis program. The device model consists of a body diode, a parasitic bipolar transistor, and elements to simulate high-current reduced breakdown. The attached photocurrent model emulates response to any pulse shape and accounts for bias-dependent depletion regions. The model can be optimized to best fit available test data

157

Impact of street geometry on downward longwave radiation and air temperature in an urban environment  

Energy Technology Data Exchange (ETDEWEB)

A study on urban geometry has been carried out with regard to urban climate in a medium-sized central European city. Thereby the interrelation between the sky view factor (SVF, the portion of visible sky seen by an observer), downward longwave radiation and air temperature was analysed to get a closer look to the interaction of horizon obstructions, thermal radiation from urban surfaces and the urban heat island. Downward longwave flux and air temperature were measured by car traverses through the city of Krefeld, Germany, during clear and calm summer nights in 2003. The traverse included sections with buildings as well as sections with vegetation. Correlation of longwave radiation and SVF was close and negative with a coefficient of determination R{sup 2} = 0.91, but urban heat island intensities (UHI, calculated from air temperature differences) along the route were weakly correlated with the SVF (0.07 {<=} R{sup 2} {<=} 0.39). With buildings, UHI increased with a reduced SVF, but no tendency was found below trees. This was probably a main result from local topographic effects (cold air accumulation). The study indicates that a nocturnal urban heat island on a microscale is not only affected by horizon obstructions, but also by the spatially variable thermal properties of materials. Moreover, advection diminishes site specific air temperature differences even during low winds. On the other hand, longwave radiation strongly depends on geometric factors and can be predicted well with the SVF. (orig.)

Blankenstein, S.; Kuttler, W. [Dept. of Applied Climatology and Landscape Ecology, Univ. of Duisburg-Essen, Essen (Germany)

2004-10-01

158

Dark Radiation Confronting LHC in Z' Models  

CERN Document Server

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.

Solaguren-Beascoa, A

2012-01-01

159

Data assimilation for air quality models  

DEFF Research Database (Denmark)

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.

Silver, Jeremy David

2014-01-01

160

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

 
 
 
 
161

Strong terahertz radiation from air plasmas generated by an aperture-limited Gaussian pump laser beam  

International Nuclear Information System (INIS)

Terahertz radiation generated by focusing the fundamental laser pulse and its second harmonic into ambient air strongly saturates with increasing pump laser energy. We demonstrate a simple method to control the Gaussian pump laser beam to improve the output of terahertz radiation with an adjustable aperture. With the optimal aperture-limited pump laser beams, the terahertz wave amplitudes can be enhanced by more than eight times depending on the pump laser parameters than those of aperture-free cases

162

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)

163

AIRFLY: Measurement of the Air Fluorescence Radiation Induced by Electrons  

Energy Technology Data Exchange (ETDEWEB)

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.

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

164

Transport worker radiation exposures handling air shipments of radioactive materials  

International Nuclear Information System (INIS)

Due to the continuing increase in the use of radioactive materials in nuclear medicine and industry there has been a corresponding rise in radioactive material (ram) package shipments via air carriers. Utilizing sensitive thermoluminescent dosimeters which were worn for 6-8 week periods annual transport worker dose estimates were made at several locations within New York State. The estimated doses as a function of transport index on the package label were as follows: freight forwarder servicing New York City Airports handled 31,000 TI units/y and 15 persons wore badges with whole body badge readings: 0.24, 0.60, 0.76, 0.78, 0.83, 0.99 and 1.69 rem/y; for a population dose of 0.36 man-rem/y, ring badges with positive results, 0.71, 1.03 and 1.11 rem/y; 5 air carriers at Buffalo Airport handled 5800 TJ units/y and 41 persons were monitored with 13 positive results: 2 at 0.24, 3 at 0.30, 0.25, 0.31, 2 at 0.37, 0.42, 0.48, 0.60, and 1.55 rem/y for a population dose of 0.14 man-rem/y, ring badge positive results: 0.24 and 6.01 rem/y; 4 freight forwarders at Buffalo Airport handled 3800 TI units/y and 52 persons were monitored with 3 positive results: 0.30, 0.36 and 0.67 rem/y for a population dose fo 0.201 man-rem/y, ring badge positive results: 0.31 and 0.42 rem/y; 4 air carriers and 3 freight forwarders at Rochester Airport handled 170 TI units/y and 19 persons wore badges and none gave an exposure above minimum detectable during monitored period. The annual population d monitored period. The annual population dose per TI were as follows: for New York City freight forwarder, 0.000012 man-rem/TI-y; for Buffalo Airport air carriers, 0.000024 man-rem/TI-y; for Buffalo Airport freight forwarder, 0.0000055 man-rem/TI-y

165

Air quality modelling using the Met Office Unified Model: model description and initial evaluation  

Directory of Open Access Journals (Sweden)

Full Text Available The on-line air quality model AQUM (Air Quality in the Unified Model is a limited-area forecast configuration of the Met Office Unified Model which uses the UKCA (UK Chemistry and Aerosols sub-model. AQUM has been developed with two aims: as an operational system to deliver regional air quality forecasts and as a modelling system to enable air quality studies to be conducted to inform policy decisions relating to emissions controls. This paper presents a description of the model and the methods used to evaluate the performance of the forecast system. Results are presented of evaluation studies conducted for a year-long period of operational forecast trials and several past cases of poor air quality episodes. To place the model performance in context we compare AQUM ozone forecasts with those of another forecasting system, the MACC ensemble, for a 5-month period. The results demonstrate that AQUM has a large dynamic range of modelled ozone levels and has a good level of responsiveness to elevated ozone episode conditions – a characteristic which is essential for forecasting poor air quality episodes. An analysis of the variation of model skill with forecast lead-time is presented and the insights this provides to the relative sources of error in air quality modelling are discussed.

N. H. Savage

2012-10-01

166

40 CFR Appendix W to Part 51 - Guideline on Air Quality Models  

Science.gov (United States)

...Air & Waste Management Association...NATO/CCMS International Technical...Review. Journal of the Air...downwash model. Journal of the Air & Waste Management Association...Receptor Model. Journal of the Air & Waste Management...

2010-07-01

167

Predictive modeling of a radiative shock system  

Energy Technology Data Exchange (ETDEWEB)

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.

Holloway, James Paul, E-mail: hagar@umich.edu [Department of Nuclear Engineering, University of Michigan, Ann Arbor, MI 48109 (United States); Bingham, Derek [Statistics and Actuarial Science, Simon Fraser University, Burnaby, BC, V5A 1S6 (Canada); Chou, Chuan-Chih; Doss, Forrest; Paul Drake, R.; Fryxell, Bruce; Grosskopf, Michael; Holst, Bart van der [Atmospheric Oceanic and Space Sciences, University of Michigan, Ann Arbor, MI 48109 (United States); Mallick, Bani K. [Department of Statistics, Texas A and M University, College Station, TX 77843-3143 (United States); McClarren, Ryan [Institute for Applied Mathematics and Computational Science, Texas A and M University, College Station, TX 77843-3133 (United States); Mukherjee, Ashin; Nair, Vijay [Department of Statistics, University of Michigan, Ann Arbor, MI 48109 (United States); Powell, Kenneth G. [Department of Aerospace Engineering, University of Michigan, Ann Arbor, MI 48109 (United States); Ryu, D. [Department of Statistics, Texas A and M University, College Station, TX 77843-3143 (United States); Sokolov, Igor; Toth, Gabor [Atmospheric Oceanic and Space Sciences, University of Michigan, Ann Arbor, MI 48109 (United States); Zhang Zhanyang [Department of Statistics, University of Michigan, Ann Arbor, MI 48109 (United States)

2011-09-15

168

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.

169

Frequency response model for thermal radiation microsensors  

International Nuclear Information System (INIS)

An analytical model is developed to determine the frequency response of thermal radiation microsensors with cantilever, bridge or membrane thermally isolated structures. In the microsensors, the domains of modelling are marked out. These domains are divided into the equivalent regions with homogeneous parameters. For each region, the non-steady-state heat conduction equation is obtained that is solved by means of the time Fourier transform. The heat flux densities between the regions are determined using adjoint boundary conditions in the frequency domain. The analytical expressions for the frequency response of the microsensors are obtained. The model is applied to the concrete thermal radiation microsensors, for which the modulus and argument of the frequency response and the time dependence of the output voltage for the step input radiation are determined

170

Coherent scattering of monochromatic RF radiation by ionization electrons of an extensive air shower  

International Nuclear Information System (INIS)

The possibility of detecting extensive air showers by recording and analyzing the radio pulse produced by the reradiation of a wave moving toward the cascade disk is considered. The coherent amplification of the scattered radiation in the direction of motion of the shower is shown to be due to a relativistic effect. An example of a real facility and its peculiarities are discussed

171

The radiation effect of high density polyethylene films in the air  

International Nuclear Information System (INIS)

The radiation effect of high density polyethylene films in the air was studied. The gel content and infrared spectra indicated the competition between cross-linking and oxidation degradation continuously after electron beam irradiation. A preliminary explanation of these results was given

172

The variability of radiative balance elements and air temperature on the Asian region of Russia  

Directory of Open Access Journals (Sweden)

Full Text Available The variability of spatial-temporal distribution of temperature and radiative and heat balances components is investigated for the Asian territory of Russia (45–80° N, 60–180° E using JRA-25, NCEP/DOE AMIP reanalysis data and observational data for the period of current global warming 1979–2008. It is shown that since the beginning of 90s of XX century the increase of back earth-atmosphere short-wave radiation is observed. Such tendency is in conformity with the cloud cover dynamics and downward short-wave radiation at the surface. Annual averaged radiative balance values at the top are negative; it is consistent with negative annual averaged air temperature, averaged over territory. The downward trend of radiative balance is the most obvious after the beginning of 90s of XX century.

E. V. Kharyutkina

2011-05-01

173

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

Science.gov (United States)

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.

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

2014-10-01

174

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)

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.

B. Zhang

2014-10-01

175

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

Science.gov (United States)

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.

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

2014-10-01

176

Modeling the exit velocity of a compressed air cannon  

Science.gov (United States)

The use of compressed air cannons in an undergraduate laboratory provides a way to illustrate the connection between diverse physics concepts, such as conservation of momentum, the work-kinetic energy theorem, gas expansion, air drag, and elementary Newtonian mechanics. However, it is not clear whether the expansion of the gas in the cannon is an adiabatic or an isothermal process. We built an air cannon that utilizes a diaphragm valve to release the pressurized gas and found that neither process accurately predicts the exit velocity of our projectile. We discuss a model based on the flow of air through the valve, which is in much better agreement with our data.

Rohrbach, Z. J.; Buresh, T. R.; Madsen, M. J.

2012-01-01

177

Decoupled predictions of radiative heating in air using a particle simulation method  

Science.gov (United States)

A particle simulation technique with decoupled radiation is used to estimate the radiative emission along the stagnation streamline and the radiative heating at the stagnation point of a blunt-nosed vehicle entering the earth's atmosphere at hypersonic speed. The direct simulation Monte Carlo (DSMC) method is used to compute the fluid mechanics of the weakly ionized flow. The radiative emission is computed using the NEQAIR computer code with the radiation decoupled from the flowfield solution. It is concluded that the new models make it possible to decrease the predicted total radiative heating at the stagnation point of the vehicle by a factor of 15. A comparison of the DSMC approach with a continuum flow model shows that the total predicted radiative heating estimates agree within a factor of 2.

Boyd, Iain D.; Whiting, Ellis E.

1992-01-01

178

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

1990-08-01

179

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

International Nuclear Information System (INIS)

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

180

Status of Galileo interim radiation electron model  

Science.gov (United States)

Measurements of the high energy, omni-directional electron environment by the Galileo spacecraft Energetic Particle Detector (EDP) were used to develop a new model of Jupiter's trapped electron radiation in the jovian equatorial plane for the range 8 to 16 Jupiter radii.

Garrett, H. B.; Jun, I.; Ratliff, J. M.; Evans, R. W.; Clough, G. A.; McEntire, R. W.

2003-01-01

 
 
 
 
181

A radiative transfer model for surface radiation budget studies  

Science.gov (United States)

A high resolution spectral radiative transfer model of the troposphere for computing downwelling radiance and flux density at the surface in the 5-200 micron region has been developed. The model is fast and accurate and takes into consideration all major and minor constituents active in this region, namely, water vapor, carbon dioxide, ozone, nitrous oxide, and methane. It uses the quasi-random band model of absorption for computing atmospheric transmittances due to various bands. Continuum absorption by water vapor in the 8-14 micron region has also been taken into account. The model has been used to examine the sensitivity of downwelling flux to variations of surface water vapor pressure (or surface relative humidity), water vapor scale-height and concentrations of other gaseous constituents of the atmosphere. In addition, sensitivity to changes in a number of cloud parameters, namely, fractional cloud cover, cloud height, and high-cloud emissivity, has also been examined. Results obtained with the present model compare well with those from the empirical and semi-empirical correlations. The present work demonstrates, for the first time, the feasibility of using a high-resolution narrow-band model for computing this flux for a meteorological application.

Gupta, S. K.

1983-01-01

182

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...

183

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

International Nuclear Information System (INIS)

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

184

Technical Note: The air quality modeling system Polyphemus  

Directory of Open Access Journals (Sweden)

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.

V. Mallet

2007-10-01

185

Technical Note: The air quality modeling system Polyphemus  

Directory of Open Access Journals (Sweden)

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.

V. Mallet

2007-05-01

186

Evaluation of models for assessing compliance with environmental radiation regulations  

International Nuclear Information System (INIS)

The use of environmental transport and dosimetry models to predict the consequences of radionuclide releases from nuclear facilities is discussed. It is pointed out that many input parameters, and hence the predictions, of these models have a high degree of variability. The determination of the uncertainties of the predictions of these models is essential for assessing the adequacy of their use to ensure compliance with radiation protection standards. Estimation of the depletion of an airborne plume via dry deposition and the subsequent transfer of materials from air to ground were studied because values of deposition velocity as applied in assessment models are often misinterpretations of the values obtained from field studies. A sensitivity analysis revealed that at distances where most maximum individual exposures would likely occur as a result of routine releases from a nuclear installation, the plume depletion model commonly used is virtually insensitive to variations in deposition velocity. This is not true, however, for the estimation of deposition, which is a linear function of deposition velocity. Therefore, any variation in the value of the deposition velocity will bring about a like variation in the estimated deposition onto vegetation or ground. The uncertainty associated with the calculation of dose to an infant's thyroid as a consequence of the transport of elemental 131I via the grass-cow-milk pathway was studied as a function of air concentration. Probabilities were determined from a statistical analysis of reported values for deposition velocity, vegetation retention, and the grass-to-milk transfer coefficient

187

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

Directory of Open Access Journals (Sweden)

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

Allen Joseph G

2008-08-01

188

An improved method for correction of air temperature measured using different radiation shields  

Science.gov (United States)

The variation of air temperature measurement errors using two different radiation shields (DTR502B Vaisala, Finland, and HYTFZ01, Huayun Tongda Satcom, China) was studied. Datasets were collected in the field at the Daxing weather station in Beijing from June 2011 to May 2012. Most air temperature values obtained with these two commonly used radiation shields were lower than the reference records obtained with the new Fiber Reinforced Polymers (FRP) Stevenson screen. In most cases, the air temperature errors when using the two devices were smaller on overcast and rainy days than on sunny days; and smaller when using the imported rather than the Chinese shield. The measured errors changed sharply at sunrise and sunset, and reached maxima at noon. Their diurnal variation characteristics were, naturally, related to changes in solar radiation. The relationships between the record errors, global radiation, and wind speed were nonlinear. An improved correction method was proposed based on the approach described by Nakamura and Mahrt (2005) (NM05), in which the impact of the solar zenith angle (SZA) on the temperature error is considered and extreme errors due to changes in SZA can be corrected effectively. Measurement errors were reduced significantly after correction by either method for both shields. The error reduction rate using the improved correction method for the Chinese and imported shields were 3.3% and 40.4% higher than those using the NM05 method, respectively.

Cheng, Xinghong; Su, Debin; Li, Deping; Chen, Lu; Xu, Wenjing; Yang, Meilin; Li, Yongcheng; Yue, Zhizhong; Wang, Zijing

2014-11-01

189

Measurement of cosmic radiation dose to air crew connecting for a typical polar route flight  

International Nuclear Information System (INIS)

In order to compare cosmic radiation dose for air crew including pilot and flight attendant between polar route flight and non-polar route flight, a typical polar flight route that is from Beijing to New York was selected and compared with non-polar route. Optically stimulated luminescence dosimeter and track etch detector CR-39 were worn as personal dosimeters to measure the cosmic radiation dose to air crew. The mean annual effective dose for air crew from polar route and non-polar route was (5.79 ± 0.92) mSv/year and (2.14 ± 0.64) mSv/year, respectively. The effective dose per 1,000 flight hours for air crew was (3.10 ± 0.27) mSv/1,000 h and (2.21 ± 0.46) mSv/1,000 h, respectively. The result is analyzed by using SPSS 15.0 statistical software. There was significant difference between the two groups for both mean annual effective dose (t = 30.25, P < 0.05) and the effective dose per 1,000 flight hours (t = 7.60, P < 0.05). The dose to pilot was higher than that of flight attendant for both polar route and non-polar route, and there was significant difference between them, for polar route (t = 7.96, P < 0.05), for non-polar route (t = 4.70, P < 0.05). The effective dose from cosmic radiation to air crew of polar route was higher than that of non-polar route, however, it did not exceed 20 mSv/year, which is the limit on cosmic radiation exposure set by many countries in the world. (author)

190

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

International Nuclear Information System (INIS)

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

191

Dispersion modeling of air pollutants in the atmosphere: a review  

Science.gov (United States)

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.

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

2014-09-01

192

COMPLEX/PFM AIR QUALITY MODEL, USER'S GUIDE  

Science.gov (United States)

A user's guide has been assembled to describe the purpose, design, and operation of the COMPLEX/PFM air quality modeling system. The system combines the features of the Potential Flow Model (PFM) with those of the EPA COMPLEX I and Complex II models to produce a potential flow co...

193

Radiative torques: analytical model and basic properties  

Science.gov (United States)

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.

Lazarian, A.; Hoang, Thiem

2007-07-01

194

40 CFR Appendix W to Part 51 - Guideline on Air Quality Models  

Science.gov (United States)

...difference, and measures of correlation...uncertainty in air pollution regulatory decisions...Guidelines on Air Quality Models...Measurements at Aluminum Reduction Plants. APCA...Mobile Source Air Quality Simulation...Application of Air Pollution...

2010-07-01

195

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

196

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

International Nuclear Information System (INIS)

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

197

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

International Nuclear Information System (INIS)

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

198

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)

199

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.

200

Problems with models of the radiation belts  

International Nuclear Information System (INIS)

The current standard models of the radiation-belt environment have many shortcomings, not the least of which is their extreme age. Most of the data used for them were acquired in the 1960's and early 1970's. Problems with the present models, and the ways in which data from more recent missions are being or can be used to create new models with improved functionality, are described. The phenomenology of the radiation belts, the effects on space systems, and geomagnetic coordinates and modeling are discussed. Errors found in present models, their functional limitations, and problems with their implementation and use are detailed. New modeling must address problems at low altitudes with the south Atlantic anomaly, east-west asymmetries and solar cycle variations and at high altitudes with the highly dynamic electron environment. The important issues in space environment modeling from the point of view of usability and relationship with effects evaluation are presented. New sources of data are discussed. Future requirements in the data, models, and analysis tools areas are presented

 
 
 
 
201

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

202

Review of air quality modeling techniques. Volume 8  

International Nuclear Information System (INIS)

Air transport and diffusion models which are applicable to the assessment of the environmental effects of nuclear, geothermal, and fossil-fuel electric generation are reviewed. The general classification of models and model inputs are discussed. A detailed examination of the statistical, Gaussian plume, Gaussian puff, one-box and species-conservation-of-mass models is given. Representative models are discussed with attention given to the assumptions, input data requirement, advantages, disadvantages and applicability of each

203

Dark Radiation in LARGE Volume Models  

CERN Document Server

We consider reheating driven by volume modulus decays in the LARGE Volume Scenario. Such reheating always generates non-zero dark radiation through the decays to the axion partner, while the only competitive visible sector decays are Higgs pairs via the Giudice-Masiero term. In the framework of sequestered models where the cosmological moduli problem is absent, the simplest model with a shift-symmetric Higgs sector generates 1.56 < N_{eff} - N_{eff,SM} < 1.74. For more general cases, the known experimental bounds on N_{eff} strongly constrain the parameters and matter content of the models.

Cicoli, Michele; Quevedo, Fernando

2012-01-01

204

Spectral modeling of radiation in combustion systems  

Science.gov (United States)

Radiation calculations are important in combustion due to the high temperatures encountered but has not been studied in sufficient detail in the case of turbulent flames. Radiation calculations for such problems require accurate, robust, and computationally efficient models for the solution of radiative transfer equation (RTE), and spectral properties of radiation. One more layer of complexity is added in predicting the overall heat transfer in turbulent combustion systems due to nonlinear interactions between turbulent fluctuations and radiation. The present work is aimed at the development of finite volume-based high-accuracy thermal radiation modeling, including spectral radiation properties in order to accurately capture turbulence-radiation interactions (TRI) and predict heat transfer in turbulent combustion systems correctly and efficiently. The turbulent fluctuations of temperature and chemical species concentrations have strong effects on spectral radiative intensities, and TRI create a closure problem when the governing partial differential equations are averaged. Recently, several approaches have been proposed to take TRI into account. Among these attempts the most promising approaches are the probability density function (PDF) methods, which can treat nonlinear coupling between turbulence and radiative emission exactly, i.e., "emission TRI". The basic idea of the PDF method is to treat physical variables as random variables and to solve the PDF transport equation stochastically. The actual reacting flow field is represented by a large number of discrete stochastic particles each carrying their own random variable values and evolving with time. The mean value of any function of those random variables, such as the chemical source term, can be evaluated exactly by taking the ensemble average of particles. The local emission term belongs to this class and thus, can be evaluated directly and exactly from particle ensembles. However, the local absorption term involves interactions between the local particle and energy emitted by all other particles and, hence, cannot be obtained from particle ensembles directly. To close the nonlinear coupling between turbulence and absorption, i.e., "absorption TRI", an optically thin fluctuation approximation can be applied to virtually all combustion problems and obtain acceptable accuracy. In the present study a composition-PDF method is applied, in which only the temperature and the species concentrations are treated as random variables. A closely coupled hybrid finite-volume/Monte Carlo scheme is adopted, in which the Monte Carlo method is used to solve the composition-PDF for chemical reactions and the finite volume method is used to solve for the flow field and radiation. Spherical harmonics method-based finite volume solvers (P-1 and P-3) are developed using the data structures of the high fidelity open-source code flow software OpenFOAM. Spectral radiative properties of the participating medium are modeled using full-spectrum k-distribution methods. Advancements of basic k-distribution methods are performed for nongray nonhomogeneous gas- and particulate-phase (soot, fuel droplets, ash, etc.) participating media using multi-scale and multi-group based approaches. These methods achieve close-to benchmark line-by-line (LBL) accuracy in strongly inhomogeneous media at a tiny fraction of LBL's computational cost. A portable spectral module is developed, which includes all the basic to advanced k-distribution methods along with the precompiled accurate and compact k-distribution databases. The P-1 /P-3 RTE solver coupled with the spectral module is used in conjunction with the combined Reynolds-averaged Navier-Stokes (RANS) and composition-PDF-based turbulence-chemistry solver to investigate TRI in multiphase turbulent combustion systems. The combustion solvers developed in this study is employed to simulate several turbulent jet flames, such as Sandia Flame D, and artificial nonsooting and sooting flames derived from Flame D. The effects of combustion chemi

Pal, Gopalendu

205

Models for the Development of Radiation Countermeasures  

Directory of Open Access Journals (Sweden)

Full Text Available Appropriate models are essential for making the transition from scientific discoveries to meaningful applications of the knowledge for human use. Acute as well as delayed effects of ionising radiation to the biological systems develop hierarchically starting from damage to the vital macromolecules up to the disturbances caused at the whole organism level. In vitro models like bacteria, yeast, various mammalian cells cultured as monolayers (2-D and spheroids (3-D as well as cells with specific genetic alterations have provided insight into the complex relationships between damage induction and various signal transduction pathways, allowing identification of molecular and sub-cellular targets vital to the fate of irradiated cells. On the other hand, in vivo models (multicellular whole organisms, ranging from simple worms to non-human primates, have been gainfully employed to evaluate efficacy as well as toxicity of potential countermeasure agents (molecules, combinations and formulated preparations facilitating their deployment in human subjects. This review provides a brief account of the efforts with various in vitro and in vivo models for understanding the biological basis of radiation damage as well as the development of radiation countermeasures, viz., protectors, mitigators and therapeutics.

Indracanti Prem Kumar

2011-03-01

206

Radiative torques: Analytical Model and Basic Properties  

CERN Document Server

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...

Lazarian, Alex

2007-01-01

207

Air Leakage of U.S. Homes: Model Prediction  

Energy Technology Data Exchange (ETDEWEB)

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

Sherman, Max H.; McWilliams, Jennifer A.

2007-01-01

208

Biologically based multistage modeling of radiation effects  

Energy Technology Data Exchange (ETDEWEB)

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

William Hazelton; Suresh Moolgavkar; E. Georg Luebeck

2005-08-30

209

Modeling ambient air quality in the Detroit-Windsor airshed  

Science.gov (United States)

The spatial variability of airborne contaminants in an international airshed was investigated using geostatistics and air dispersion modeling. Analyses were conducted on contaminant species measured in Detroit and Windsor over a two-week period during September 2008. Ordinary kriging with anisotropy and cokriging of measurements with different scales of support were expected to improve estimates generated with autocorrelated ordinary kriging models. Available emissions and meteorological data were also integrated into an air dispersion model to test the feasibility of predicting spatial variability using emissions inventories and traffic estimates for two of the sampled air pollutants, benzene and nitrogen dioxide (NO2). Results showed no improvement for models incorporating anisotropy. Cokriging improved correlation coefficients and reduced residual statistics for some pollutant concentration estimates compared to ordinary kriging. This suggests that, under favorable conditions, secondary data can be used to increase the spatial resolution of concentration estimates while improving model agreement with field measurements.

Molaroni, Shannon M.

210

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)

211

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

Science.gov (United States)

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

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

2014-09-01

212

Modeling air temperature changes in Northern Asia  

Science.gov (United States)

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.

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

2014-11-01

213

Modeling of sound radiation by a beam  

Directory of Open Access Journals (Sweden)

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.

?.?. Zaporozhets

2005-03-01

214

Air-quality modelling in the Lake Baikal region.  

Science.gov (United States)

In this paper, we assess the status of the air quality in the Lake Baikal region which is strongly influenced by the presence of anthropogenic pollution sources. We combined the local data, with global databases, remote sensing imagery and modelling tools. This approach allows to inventorise the air-polluting sources and to quantify the air-quality concentration levels in the Lake Baikal region to a reasonable level, despite the fact that local data are scarcely available. In the simulations, we focus on the month of July 2003, as for this period, validation data are available for a number of ground-based measurement stations within the Lake Baikal region. PMID:19496003

Van de Vel, Karen; Mensink, Clemens; De Ridder, Koen; Deutsch, Felix; Maes, Joachim; Vliegen, Jo; Aloyan, Artash; Yermakov, Alexander; Arutyunyan, Vardan; Khodzher, Tamara; Mijling, Bas

2010-06-01

215

Studies on curing effect of phosphite monomer by EB radiation in the air  

International Nuclear Information System (INIS)

A new type phosphite active monomer was synthesized. The resisting oxygen inhibition effect of this monomer and the effects of irradiation dose and concentration of phosphite active monomer on curing were studied. At the same time, curing results were analysed, through gel content and IR spectrum. The excellent resisting oxygen inhibition result of this phosphite active monomer was shown by experiments. EB radiation curing in the air was successfully carried out by the phosphite active monomer. (author)

216

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

International Nuclear Information System (INIS)

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

217

Modelling the emission of pesticides from covered structures to air  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Emissions of plant protection products (PPP) from covered structures to the air outside were estimated to support the European Food Safety Authority (EFSA) in the development of guidance on risk assessments for protected crops. Such emissions are mainly caused by loss of volatilised PPPs through the vents in the covered structures. The newly developed VEGA model (Ventilated Emissions from Greenhouse to Air) describes the fate of PPPs after a spray application inside covered structures. Simula...

Holterman, H. J.; Sapounas, A.; Beulke, S.; Os, E. A.; Glass, C. R.

2012-01-01

218

Atmospheric transmittance model for photosynthetically active radiation  

Energy Technology Data Exchange (ETDEWEB)

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.

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

219

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)

220

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

DEFF Research Database (Denmark)

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.

Delfs, Jens Olaf; Wang, Wenqing

2013-01-01

 
 
 
 
221

Modeling air entrainment in plunging jet using 3DYNAFS  

CERN Document Server

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

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

2011-01-01

222

75 FR 56487 - Airworthiness Directives; Erickson Air-Crane Incorporated Model S-64F Helicopters  

Science.gov (United States)

...2120-AA64 Airworthiness Directives; Erickson Air-Crane Incorporated Model S-64F Helicopters AGENCY...airworthiness directive (AD) for Erickson Air-Crane Incorporated (Erickson Air-Crane) Model S- 64F helicopters. The AD would...

2010-09-16

223

76 FR 66617 - Airworthiness Directives; Erickson Air-Crane Incorporated Model S-64F Helicopters  

Science.gov (United States)

...2120-AA64 Airworthiness Directives; Erickson Air-Crane Incorporated Model S-64F Helicopters AGENCY: Federal...airworthiness directive (AD) for the Erickson Air-Crane (Erickson Air-Crane) Model S-64F helicopters. The amendment...

2011-10-27

224

40 CFR Appendix W to Part 51 - Guideline on Air Quality Models  

Science.gov (United States)

...downwash model. Journal of the Air & Waste Management Association ...Receptor Model. Journal of the Air & Waste Management Association ...April 4-6, 2001, Newport, RI, Air & Waste Management Association....

2010-07-01

225

AN INDOOR AIR QUALITY MODEL FOR PARTICULATE MATTER  

Science.gov (United States)

Thye paper discusses an indoor air quality (IAQ) model for particulate matter (PM). The standard for PM < 2.5 micrometers in aerodynamic diameter (PM 2.5) proposed by the U.S. EPA has produced considerable interest in indoor exposures to PM. IAQ models provide a useful tool for...

226

A PHOTOCHEMICAL BOX MODEL FOR URBAN AIR QUALITY SIMULATION  

Science.gov (United States)

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

227

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

Directory of Open Access Journals (Sweden)

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.

A. Gallice

2011-10-01

228

Assessing The Policy Relevance of Regional Air Quality Models  

Science.gov (United States)

This work presents a framework for discussing the policy relevance of models, and regional air quality models in particular. We define four criteria: 1) The scientific status of the model; 2) Its ability to address primary environmental concerns; 3) The position of modeled environmental issues on the political agenda; and 4) The role of scientific input into the policy process. This framework is applied to current work simulating the transport of nitric acid in Asia with the ATMOS-N model, to past studies on air pollution transport in Europe with the EMEP model, and to future applications of the United States Environmental Protection Agency (US EPA) Models-3. The Lagrangian EMEP model provided critical input to the development of the 1994 Oslo and 1999 Gothenburg Protocols to the Convention on Long-Range Transbound- ary Air Pollution, as well as to the development of EU directives, via its role as a component of the RAINS integrated assessment model. Our work simulating reactive nitrogen in Asia follows the European example in part, with the choice of ATMOS-N, a regional Lagrangian model to calculate source-receptor relationships for the RAINS- Asia integrated assessment model. However, given differences between ATMOS-N and the EMEP model, as well as differences between the scientific and political cli- mates facing Europe ten years ago and Asia today, the role of these two models in the policy process is very different. We characterize the different aspects of policy relevance between these models using our framework, and consider how the current generation US EPA air quality model compares, in light of its Eulerian structure, dif- ferent objectives, and the policy context of the US.

Holloway, T.

229

Radiation monitoring of air crew and estimation of radiation exposure of solar events: ACREM results  

International Nuclear Information System (INIS)

Different dose assessment methods were discussed and were evaluated by several international research groups. The basic concept of the TEPC (tissue equivalent proportional counter) as well as experimental results in well defined calibration fields and in-flight measurement indicate that it represents an appropriate H*(10)-reference dosimeter. Several active conventional photon as well as neutron detector instruments have been prepared and characterised for in-flight measurements during the ACREM project. Comparison of in-flight measurements with numerical calculations of the cosmic ray transport through the atmosphere have been carried out. Cosmic-ray intensities vary over an approximate, predictable situation of eleven-year cycle. However, spontaneous events on the sun can lead to unforeseen, high, additional radiation exposure. Appropriate methods to determine their radiation exposure have been worked out during the ACREM project. (orig.)

230

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

Directory of Open Access Journals (Sweden)

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%.

N. Stuber

2007-06-01

231

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

232

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

233

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

234

Mathematical model of an air-filled alpha stirling refrigerator  

Science.gov (United States)

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.

McFarlane, Patrick; Semperlotti, Fabio; Sen, Mihir

2013-10-01

235

A Hybrid Neural Network Prediction Model of Air Ticket Sales  

Directory of Open Access Journals (Sweden)

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.

Han-Chen Huang

2013-11-01

236

Radiative equilibrium model of Titan's atmosphere  

Science.gov (United States)

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.

Samuelson, R. E.

1983-01-01

237

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.

238

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

International Nuclear Information System (INIS)

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

239

Modeling the Environmental Impact of Air Traffic Operations  

Science.gov (United States)

There is increased interest to understand and mitigate the impacts of air traffic on the climate, since greenhouse gases, nitrogen oxides, and contrails generated by air traffic can have adverse impacts on the climate. The models described in this presentation are useful for quantifying these impacts and for studying alternative environmentally aware operational concepts. These models have been developed by leveraging and building upon existing simulation and optimization techniques developed for the design of efficient traffic flow management strategies. Specific enhancements to the existing simulation and optimization techniques include new models that simulate aircraft fuel flow, emissions and contrails. To ensure that these new models are beneficial to the larger climate research community, the outputs of these new models are compatible with existing global climate modeling tools like the FAA's Aviation Environmental Design Tool.

Chen, Neil

2011-01-01

240

An Analytical Air Pollution Model with Time Dependent Eddy Diffusivity  

Directory of Open Access Journals (Sweden)

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.

Tiziano Tirabassi

2013-07-01

 
 
 
 
241

Two dimensional model for coherent synchrotron radiation  

Science.gov (United States)

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

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

2013-01-01

242

Modelling non-isothermal flow and air leakage in a steel reheating furnace  

Energy Technology Data Exchange (ETDEWEB)

This progress report will give a brief summary on the modeling of the steel reheating furnace at Rautaruukki Oy carried out in Spring 1997 (January - June), after the basic 3-D flow model for the industrial scale steel reheating fumace in 1996. The current report includes the following modelling tasks: (1) Improving the convergence of the basic flow models, (2) Non-isothermal flow model with convective heat transfer, (3) Non-isothermal flow models for air leakage at charge and discharge doors, (4) Preliminary radiative heat transfer models. A reliable gas flow pattern is very important for the modelling of the fumace heat transfer. Gas flow in principle dominates the heat transfer characteristics and the temperature distribution in the fumace. The previous 3-D gas model was preliminary, and the main objectives were to construct the basic flow model, test the model workability, and obtain approximate flow pattern. Air leakage into the reheating fumace takes place in the charge and discharge doors of the fumace during operation. It not only brings local and overall cooling in the fumace, but also may cause extra oxidation to the steel slab surfaces and thus increase surface scaling. Therefore, it is important to known how the leakage air is mixed with the combustion gases and where the air travels in the fumace. Radiative heat transfer plays very important role in the total heat transfer to the slabs in the fumace. Radiation heat transfer modeling is the final goal in this project. A lot of efforts have been made for improving the convergence in the computation, in order to obtain more reliable gas flow pattern and mixing behaviour. The model is very difficult to converge due to the high velocity difference from 3 sets of gas burners. Different scales of relaxation factors were tested, but no efficient factors were found. EXPERT system as well as the local relaxation near the burner regions could not give reasonable improvements in convergence. In addition to the on-line relaxation parameter changes, a new automatic relaxation tool SARAH provided in PHOENICS 2.2 was also used to speed the convergence. It gave some help, but did not solve the convergence problem completely. One useful hint proved from the SARAH test is that the relaxation factors for velocity components should be much higher than the ones suggested by the menu system, and much higher than the factors EXPERT gives. This helped the later manual tests which gave finally a reasonable set of factors. In the current report, good convergence were reached in all the models, with the optimised relaxation factors. Air leaked into the furnace at about room temperature with different thermophysical properties, especially the density and viscosity. This non-isothermal mixing with hot gases cannot be realistically modeled unless heat transfer is taken into account. Before the full radiation models are established, convective heat transfer was considered in the air leakage models. In the convective heat transfer models, the non-isothermal mixing behaviour of air with hot gases can almost be represented, because the total cooling due to radiative heat transfer in the furnace is not very high. At the same time, a convective heat transfer model was made, in order to check the flow pattern change due to heat transfer. In the models with convective heat transfer, a through model debugging was carried out in order to get correct and complete wall boundary conditions. After the air leakage tests, a complete radiative heat transfer model was constructed. In this model, complete wall temperature and radiation boundary conditions were established. Detailed division of slab upper/lower surfaces as well as for other solid surfaces with different temperatures were made. In the beginning, conflict of GRND3 non-equilibrium wall functions with the six-flux model was encountered. It always overflew during the model ending stage for result file writing. Debugging of different wall radiation patches and covals didn`t give any explanation. Checking carefully the result files, it was found th

Yang Yongxiang; Jokilaakso, A.

1997-12-31

243

Modeling Air Stripping of Ammonia in an Agitated Vessel  

Energy Technology Data Exchange (ETDEWEB)

A model has been developed to predict the rate of removal of ammonia (NH{sub 3}) from solution in a sparged agitated vessel. The model is first-order with respect to liquid-phase concentration of NH{sub 3}. The rate constant for the first-order equation is a function of parameters related to the vessel/impeller characteristics, the air/liquid properties as well as the process conditions. However, the vessel/impeller characteristics, the air/liquid properties, and the process conditions reduce the rate constant dependence to only three parameters, namely, the air sparge rate, the liquid volume or batch size, and the Henry's law constant of NH{sub 3} for the liquid or solution. Thus, the rate of removal is not mass-transfer limited. High air sparge rates, high temperatures, and low liquid volumes or batch sizes increase the rate of removal of NH{sub 3} from solution. The Henry's law constant effect is somewhat reflected in the temperature since Henry's law constant increases with increasing temperature. Data obtained from actual air stripping operation agree fairly well with the model predictions.

Kofi, Adu-Wusu; Martino, Christopher J.; Wilmarth, William R.; Bennett, William M.; Peters, Robert s.

2005-11-29

244

A 331 WIMPy dark radiation model  

Energy Technology Data Exchange (ETDEWEB)

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

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

2014-03-15

245

A 331 WIMPy dark radiation model  

International Nuclear Information System (INIS)

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

246

A 331 WIMPy Dark Radiation Model  

CERN Document Server

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

Kelso, Chris; Profumo, Stefano; Queiroz, Farinaldo S; da Silva, P S Rodrigues

2013-01-01

247

Radiation damage in graphite - A new model  

International Nuclear Information System (INIS)

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

248

LANL*: Radiation belt drift shell modeling  

Science.gov (United States)

LANL* calculates the magnetic drift invariant L*, used for modeling radiation belt dynamics and other space weather applications, six orders of magnitude (~ one million times) faster than convectional approaches that require global numerical field lines tracing and integration. It is based on a modern machine learning technique (feed-forward artificial neural network) by supervising a large data pool obtained from the IRBEM library, which is the traditional source for numerically calculating the L* values. The pool consists of about 100,000 samples randomly distributed within the magnetosphere (r: [1.03, 11.5] Re) and within a whole solar cycle from 1/1/1994 to 1/1/2005. There are seven LANL* models, each corresponding to its underlying magnetic field configuration that is used to create the data sample pool. This model has applications to real-time radiation belt forecasting, analysis of data sets involving tens of satellite-years of observations, and other problems in space weather.

Yu, Yiqun; Koller, Josef

2014-09-01

249

Measurement and Modeling of Particle Radiation in Coal Flames  

DEFF Research Database (Denmark)

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.

Ba?ckstro?m, Daniel; Johansson, Robert

2014-01-01

250

The Dutch standard on the description of air pollution models  

International Nuclear Information System (INIS)

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

251

Parametric model for the Saturn radiation field  

International Nuclear Information System (INIS)

The angular momentum of a magnetized rotating ring system is shown to be responsible for the lack of significant synchrotron radiation (beyond 1.6 Rs), even though the large magnetic field is 11.3 gauss. A corollary is evolved which says that large ring rotational energy is a manifestation of little nonthermal radiation. This observation is virtually independent of the magnitude of the magnetic field. The model generates an induced electric field capable of accelerating electrons and protons to relativistic energies (approximately 0.9 GeV) and ejecting them from the ring plane. The electric field is necessary to create a magnetosphere coupled to the magnetic field. This leads to nonthermal radiation and ring momentum loss. This mechanism is considered part of a dynamic exchange with the conductive dust particles and charged particles of the Saturn environment; that is, the rings are a visible link with the magnetosphere and satellite system. Spatial quantization is proposed as a mechanism for the evolution of the single but true ring separation called the Cassini Division

252

Modeling the radiation response of Chlamydomonas reinhardi  

International Nuclear Information System (INIS)

To pursue our goal of establishing quantitative relations between initial physical events produced by ionizing radiation and the subsequent biological effects in cells, we have been developing and testing theoretical models for two kinds of cells, the mammalian Chinese hamster ovary (CHO) cell and the green alga, Chlamydomonas reinhardi. The hamster cell studies are beginning to produce results and will be discussed below. The C. reinhardt studies have been in progress for some time and illustrate the normal scientific cycle of framing, testing, and revising hypotheses

253

Biological models in epidemiology: radiation carcinogenesis  

International Nuclear Information System (INIS)

The status of ionizing radiation as one of the common environmental causes of cancer is introduced. Relying on the considerable body of theoretical and experimental radiobiology to provide a theoretical framework and the basic scientific principle of consistency or results among different populations, differently exposed, the validity of objections is considered. First radiobiological theory and then the studies of the Japanese A-Bomb survivors are presented, the latter in detail with tables of measurements. Final discussion suggests applications and future study needed and eventually refined estimates of risk when new models are applied to epidemiological data

254

Guidelines for air quality dispersion models critical review and recommendations  

Energy Technology Data Exchange (ETDEWEB)

The need for guidelines for air quality dispersion models for regulatory purposes has long been recognized by the British Columbia Ministry of Water, Land and Air Protection. A critical review of the most recent draft guidelines was performed by SENES Consultants Limited, to evaluate their approach, completeness and content, as well as to provide a direction for revisions and completion of a final guideline document. Specifically, the authors reviewed how technical information is gathered and compared approaches used by other jurisdictions. They incorporated operational realities based on the historical application of models in British Columbia and presented options and recommendations for the development of the guidelines. It was found that although information was provided, in many instances no specific guidance was offered. The lack of an overall modelling philosophy for regulatory applications in British Columbia was recognized as the main weakness of the draft document. Two options were examined: a tiered modelling approach following United States Environmental Protection Agency (USEPA) guidance; and a British Columbia appropriate modelling approach based on a non-steady state Gaussian puff model developed by the Sigma Research Corporation for the California Air Resources Board (CALPUFF) model. It was recommended that specific guidelines be limited to technical aspects regarding which models should be used and under what circumstances. 14 refs., 2 tabs., 11 figs.

Hrebenyk, B.W.; Young, J.W.S.; Radonjic, Z.R. [SENES Consultants Ltd., Vancouver, BC (Canada)

2003-05-08

255

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

Science.gov (United States)

An appropriate method for evaluating the air quality of a certain area is to contrast the actual air pollution levels to the critical ones, prescribed in the legislative standards. The application of numerical simulation models for assessing the real air quality status is allowed by the legislation of the European Community (EC). This approach is preferable, especially when the area of interest is relatively big and/or the network of measurement stations is sparse, and the available observational data are scarce, respectively. Such method is very efficient for similar assessment studies due to continuous spatio-temporal coverage of the obtained results. In the study the values of the concentration of the harmful substances sulphur dioxide, (SO2), nitrogen dioxide (NO2), particulate matter - coarse (PM10) and fine (PM2.5) fraction, ozone (O3), carbon monoxide (CO) and ammonia (NH3) in the surface layer obtained from modelling simulations with resolution 10 km on hourly bases are taken to calculate the necessary statistical quantities which are used for comparison with the corresponding critical levels, prescribed in the EC directives. For part of them (PM2.5, CO and NH3) this is done for first time with such resolution. The computational grid covers Bulgaria entirely and some surrounding territories and the calculations are made for every year in the period 1991-2000. The averaged over the whole time slice results can be treated as representative for the air quality situation of the last decade of the former century. PMID:23556142

Chervenkov, Hristo

2013-12-01

256

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

Directory of Open Access Journals (Sweden)

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.

A Majnoni-Heris

2009-01-01

257

Validation of a 3-D hemispheric nested air pollution model  

Directory of Open Access Journals (Sweden)

Full Text Available Several air pollution transport models have been developed at the National Environmental Research Institute in Denmark over the last decade (DREAM, DEHM, ACDEP and DEOM. A new 3-D nested Eulerian transport-chemistry model: REGIonal high resolutioN Air pollution model (REGINA is based on modules and parameterisations from these models as well as new methods.

The model covers the majority of the Northern Hemisphere with currently one nest implemented. The horizontal resolution in the mother domain is 150 km × 150 km, and the nesting factor is three. A chemical scheme (originally 51 species has been extended with a detailed description of the ammonia chemistry and implemented in the model. The mesoscale numerical weather prediction model MM5v2 is used as meteorological driver for the model. The concentrations of air pollutants, such as sulphur and nitrogen in various forms, have been calculated, applying zero nesting and one nest. The model setup is currently being validated by comparing calculated values of concentrations to measurements from approximately 100 stations included in the European Monitoring and Evalutation Programme (EMEP.

The present paper describes the physical processes and parameterisations of the model together with the modifications of the chemical scheme. Validation of the model calculations by comparison to EMEP measurements for a summer and a winter month is shown and discussed. Furthermore, results from a sensitivity study of the model performance with respect to resolution in emission and meteorology input data is presented. Finally the future prospects of the model are discussed.

The overall validation shows that the model performs well with respect to correlation for both monthly and daily mean values.

L. M. Frohn

2003-07-01

258

MODEL PENGELOLAAN AIR BERSIH DESA DI BANTUL YOGYAKARTA  

Directory of Open Access Journals (Sweden)

Full Text Available AbstrakArtikel ini bertujuan mendeskripsikan model pengelolaan air minum desa dan permasalah yang dihadapinya. Penelitian dilakukan di wilayah Pucung Desa Wukirsari Bantul Yogyakarta. Permasalahan yang dikaji adalah bagaimana pengelolaan  ditinjau dari aspek kelembagaan, ketersediaan air, jumlah pengguna, kebutuhan air bersih, pedoman yang mengatur dan manajemen keuangannya. Jenis penelitian survai dengan pendekatan deskriptif kualitatif dan kuantitatif. Subyek penelitian kepala keluarga. Hasil penelitian Pengelolaan Air Bersih (PAB Pucung dikelola berbasis masyarakat (tipe C, namun belum melibatkan pelanggan dalam pengelolaannya. Ketersediaan air sangat cukup, tetapi kebutuhan pelanggan belum terpenuhi secara maksimal. Apabila PAB Pucung dapat beroperasi secara efektif dan efisien masyarakat Pucung tidak akan kekurangan air bersih karena dalam satu bulan masih tersedia 13.445 m3, yang setara  dengan pemenuhan kebutuhan air bersih rata–rata 259 jiwa/bulan.AbstractThis article aims to describe a village water management model and the problems it faces. The study was conducted in the area of ??Bantul, Yogyakarta, to be exactly in Wukirsari village. The article studies water management in the aspect of institutional management, water availability, number of users, the need for clean water, and guidelines governing financial management. The results of the study reveals that the water is managed by the community (type C, and do not involve the customer in its management. Though water is abundant, the management does not meet customer needs to the fullest. If PAB Pucung can operate effectively and efficiently Pucung people will not lack of clean water because of lack of clean water is still available in a month 13 445 m3, which is equivalent to a clean water supply on average 259 people/month.© 2013 Universitas Negeri Semarang

Hardjono -

2014-02-01

259

AQMEII: A New International Initiative on Air Quality Model Evaluation  

Science.gov (United States)

We provide a conceptual view of the process of evaluating regional-scale three-dimensional numerical photochemical air quality modeling system, based on an examination of existing approached to the evaluation of such systems as they are currently used in a variety of application....

260

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...

 
 
 
 
261

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)

262

Four-dimensional evaluation of regional air quality models  

Directory of Open Access Journals (Sweden)

Full Text Available The evaluation of regional air quality models is a challenging task, not only for the intrinsic complexity of the topic but also in view of the difficulties in finding sufficiently abundant, harmonized and time/space-well-distributed measurement data. This study, conducted in the framework of AQMEII (Air Quality Model Evaluation International Initiative, evaluates 4-D model predictions obtained from 15 modelling groups and relating to the air quality of the full year of 2006 over the North American and European continents. The modelled variables are ozone, CO, wind speed and direction, temperature, and relative humidity. Model evaluation is supported by the high quality in-flight measurements collected by instrumented commercial aircrafts in the context of the MOZAIC programme. The models are evaluated at five selected domains positioned around major airports, four in North America (Portland, Philadelphia, Atlanta, Dallas and one in Europe (Frankfurt. Due to the extraordinary scale of the exercise (number of models and variables, spatial and temporal extent, this study is primarily aimed at illustrating the potential for using MOZAIC data for regional-scale evaluation and the capabilities of models to simulate concentration and meteorological fields in the vertical rather than just at the ground. We apply various approaches, metrics, and methods to analyze this complex dataset. Results of the investigation indicate that, while the observed meteorological fields are modelled with some success, modelling CO in and above the boundary layer remains a challenge and modelling ozone also has room for significant improvement. We note, however, that the high sensitivity of models to height, season, location, and metric makes the results rather difficult to interpret and to generalize. With this work, though, we set the stage for future process-oriented and in-depth diagnostic analyses.

E. Solazzo

2013-01-01

263

Direct radiative effect of the Russian wildfires and their impact on air temperature and atmospheric dynamics during August 2010  

Science.gov (United States)

The present study aims at investigating the shortwave aerosol direct radiative forcing (ADRF) and its feedback on air temperature and atmospheric dynamics during a major fire event that occurred in Russia during August 2010. The methodology is based on an off-line coupling between the CHIMERE chemistry-transport and the Weather Research and Forecasting (WRF) models. First, simulations for the period 5-12 August 2010 have been evaluated by using AERONET and satellite measurements of the POLarization and Directionality of the Earth's Reflectance (POLDER) and the Cloud-Aerosol LIdar with Orthogonal Polarization (CALIOP) sensors. During this period, elevated POLDER AOT are found over a large part of Eastern Europe with values above 2 (at 550 nm) in the aerosol plume. According to CALIOP observations, particles remain confined within the first five kilometres of the atmospheric layer. Comparisons with satellite measurements show the ability of CHIMERE to reproduce the regional and vertical distribution of aerosols during their transport from the source region. Over Moscow, AERONET measurements indicate an important increase of AOT (340 nm) from 0.7 on 5 August to 2-4 between 6 and 10 August when the aerosol plume is advected over the city. Particles are mainly observed in the fine size mode (radius in the range 0.2-0.4 ?m) and are characterized by elevated SSA (0.95-0.96 between 440 and 1020 nm). Also, comparisons of simulations with AERONET measurements show that aerosol physical-optical properties (size distribution, AOT, SSA) have been well simulated over Moscow in term of intensity and/or spectral dependence. Secondly, modelled aerosol optical properties have been used as input in the radiative transfer code of WRF to evaluate their direct radiative impact. Simulations indicate a significant reduction of solar radiation at the ground (up to 80-150 W m-2 in diurnal-averaged) over a large part of Eastern Europe due to the presence of the aerosol plume. This ADRF causes an important reduction of the near-surface air temperature between 0.2 and 2.6°C at a regional scale. Moscow has been also affected by the aerosol plume, especially between 6 and 10 August. During this period, aerosol causes a significant reduction of surface shortwave radiation (up to 70-84 W m-2 in diurnal-averaged) with a moderate part (20-30%) due to solar absorption within the aerosol layer. The resulting feedbacks lead to a cooling of the air up to 1.6°C at the surface and 0.1°C at an altitude of 1500-2000 m (in diurnal-averaged), that contribute to stabilize the atmospheric boundary layer (ABL). Indeed, a reduction of the ABL height of 13 to 65% have been simulated during daytime in presence of aerosols. This decrease is the result of a lower air entrainment as the vertical wind speed in the ABL is shown to be reduced by 5 to 80% (at midday) when the feedback of the ADRF is taken into account. In turn, CHIMERE simulations driven by the WRF meteorological fields including this ADRF feedback result in a large increase in the modeled near-surface PM10 concentrations (up to 99%) due to their lower vertical dilution in the ABL, which tend to reduce model biases with the ground PM10 values observed over Moscow during this specific period.

Péré, J. C.; Bessagnet, B.; Mallet, M.; Waquet, F.; Chiapello, I.; Minvielle, F.; Pont, V.; Menut, L.

2013-06-01

264

Direct radiative effect of the Russian wildfires and its impact on air temperature and atmospheric dynamics during August 2010  

Science.gov (United States)

In this study, we investigate the shortwave aerosol direct radiative forcing (ADRF) and its feedback on air temperature and atmospheric dynamics during a major fire event that occurred in Russia during August 2010. The methodology is based on an offline coupling between the CHIMERE chemistry-transport and the Weather Research and Forecasting (WRF) models. First, simulations for the period 5-12 August 2010 have been evaluated by using AERONET (AErosol RObotic NETwork) and satellite measurements of the POLarization and Directionality of the Earth's Reflectance (POLDER) and the Cloud-Aerosol LIdar with Orthogonal Polarization (CALIOP) sensors. During this period, elevated POLDER aerosol optical thickness (AOT) is found over a large part of eastern Europe, with values above 2 (at 550 nm) in the aerosol plume. According to CALIOP observations, particles remain confined to the first five kilometres of the atmospheric layer. Comparisons with satellite measurements show the ability of CHIMERE to reproduce the regional and vertical distribution of aerosols during their transport from the source region. Over Moscow, AERONET measurements indicate an important increase of AOT (340 nm) from 0.7 on 5 August to 2-4 between 6 and 10 August when the aerosol plume was advected over the city. Particles are mainly observed in the fine size mode (radius in the range 0.2-0.4 ?m) and are characterized by elevated single-scattering albedo (SSA) (0.95-0.96 between 440 and 1020 nm). Comparisons of simulations with AERONET measurements show that aerosol physical-optical properties (size distribution, AOT, SSA) have been well simulated over Moscow in terms of intensity and/or spectral dependence. Secondly, modelled aerosol optical properties have been used as input in the radiative transfer code of WRF to evaluate their direct radiative impact. Simulations indicate a significant reduction of solar radiation at the ground (up to 80-150 W m-2 in diurnal averages over a large part of eastern Europe due to the presence of the aerosol plume. This ADRF causes an important reduction of the near-surface air temperature between 0.2 and 2.6° on a regional scale. Moscow has been affected by the aerosol plume, especially between 6 and 10 August. During this period, aerosol causes a significant reduction of surface shortwave radiation (up to 70-84 W m-2 in diurnal averages) with a moderate part (20-30%) due to solar absorption within the aerosol layer. The resulting feedbacks lead to a cooling of the air up to 1.6° at the surface and 0.1° at an altitude of 1500-2000 m (in diurnal averages), that contribute to stabilize the atmospheric boundary layer (ABL). Indeed, a reduction of the ABL height of 13 to 65% has been simulated during daytime in presence of aerosols. This decrease is the result of a lower air entrainment as the vertical wind speed in the ABL is shown to be reduced by 5 to 80% (at midday) when the feedback of the ADRF is taken into account. However, the ADRF is shown to have a lower impact on the horizontal wind speed, suggesting that the dilution of particles would be mainly affected by the weakening of the ABL development and associated vertical entrainment. Indeed, CHIMERE simulations driven by the WRF meteorological fields including this ADRF feedback result in a large increase in the modelled near-surface PM10 concentrations (up to 99%). This is due to their lower vertical dilution in the ABL, which tend to reduce model biases with the ground PM10 values observed over Moscow during this specific period.

Péré, J. C.; Bessagnet, B.; Mallet, M.; Waquet, F.; Chiapello, I.; Minvielle, F.; Pont, V.; Menut, L.

2014-02-01

265

Modeling three-dimensional Monte Carlo radiative transfer for analysis of cloud-resolving radiation budget  

Science.gov (United States)

Clouds have greenhouse effects that prevent cooling of surface and lower atmosphere by absorbing terrestrial radiation, along with cooling effects by blocking the solar radiation. Those effects play an important role in determining the Earth's radiation budget which varies regionally and seasonally. Especially, complex geometry and inhomogeneity in clouds affect significantly on the radiative energy distribution of solar radiation and terrestrial radiation. Modeling of clouds and three-dimensional radiative processes are key issues for reliable simulations of cloud-resolving radiation budget. In this study, three-dimensional atmospheric radiative transfer model has been developed for the purpose of evaluating cloud-resolving radiation budget. For the radiation budget evaluation, many broadband calculations covering solar and terrestrial radiations in complex geometry and inhomogeneous cloud system are required. In addition, multiple-scattering and absorption effects should be taken into account properly to radiative transfer process. Those requirements to radiative transfer calculation tend to make it complicated and time-consuming scheme. Monte Carlo method has been employed in this study, because the method is easily applicable to complex three-dimensional system and suitable to broadband calculation rather than explicit analytical radiative transfer scheme. Especially, the method of dependent sampling has been employed in order to calculate more than one wavelength at the same time. The method is applicable to both solar and terrestrial radiative transfer, and enables efficient broadband calculations of radiative flux and heating rate. Performance, validation and application of the Monte Carlo radiative transfer model developed in this study will be presented and discussed from the point of analysis of cloud-resolving radiation budget.

Ota, Y.

2012-12-01

266

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

Science.gov (United States)

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

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

1994-01-01

267

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)

268

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

269

Radiation creep model, considering dislocation slip and climb an obstacle  

International Nuclear Information System (INIS)

A generalized model of radiation creep based on edge dislocation slip and climb is described. A formula is deduced. It helps to obtain, as an individual case, expressions for radiation creep velocity, presented by the known before SIPA, SIAD, Gittus-Mansur, slip-climb models. Dependences of radiation creep on temperature, stress, radiation dose are calculated; comparison with the corresponding experimental data for reactor steels is carried out

270

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

271

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

272

Radiation transfer through a model sunspot  

Science.gov (United States)

A cylindrically symmetric model for a sunspot atmosphere using the similarity principle of Schlueter and Temesvary for the magnetic field configuration is presented. The equations of magnetostatic equilibrium are used, augmented by a radial Evershed flow. The LTE radiative transfer equations for the Stokes vector were solved under a variety of conditions for a ray emerging from a typical penumbral point. The contribution from isolated lines to the broadband circular polarization in sunspot penumbrae is evaluated using a more realistic model sunspot atmosphere than has hitherto been considered. Results indicate that the inclusion of a velocity field along the magnetic field vector is unable to give a net circular polarization of sufficient magnitude, although the variation with the angle between the line-of-sight and the magnetic field vector is in qualitative agreement with observations. The corresponding results for the net linear polarization are satisfactory.

Landman, D. A.; Finn, G. D.

1979-01-01

273

Controlling indoor air pollution from tobacco smoke: models and measurements  

Energy Technology Data Exchange (ETDEWEB)

The effects of smoking rate, ventilation, surface deposition, and air cleaning on the indoor concentrations of respirable particulate matter and carbon monoxide generated by cigarette smoke are examined. A general mass balance model is presented which has been extended to include the concept of ventilation efficiency. Following a review of the source and removal terms associated with respirable particles and carbon monoxide, model predictions to various health guidelines are compared. 20 references, 1 figure.

Offermann, F.J.; Girman, J.R.; Sextro, R.G.

1984-07-01

274

Modeling of air pollution from the power plant ash dumps  

Science.gov (United States)

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.

Aleksic, Nenad M.; Bala?, Nedeljko

275

Spatial distribution of emissions to air – the SPREAD model  

DEFF Research Database (Denmark)

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.

Plejdrup, Marlene Schmidt; Gyldenkærne, Steen

2011-01-01

276

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)

277

Heat transfer in Rockwool modelling and method of measurement. Modelling radiative heat transfer in fibrous materials  

Energy Technology Data Exchange (ETDEWEB)

Fibrous materials are some of the most widely used materials for thermal insulation. In this project the focus of interest has been on fibrous materials for building application. Interest in improving the thermal properties of insulation materials is increasing as legislation is being tightened to reduce the overall energy consumption. A knowledge of the individual heat transfer mechanisms - whereby heat is transferred within a particular material is an essential tool to improve continuously the thermal properties of the material. Heat is transferred in fibrous materials by four different transfer mechanisms: conduction through air, conduction through fibres, thermal radiation and convection. In a particular temperature range the conduction through air can be regarded as a constant, and conduction through fibres is an insignificant part of the total heat transfer. Radiation, however, constitutes 25-40% of the total heat transfer in light fibrous materials. In Denmark and a number of other countries convection in fibrous materials is considered as non-existent when calculating heat transmission as well as when designing building structures. Two heat transfer mechanisms have been the focus of the current project: radiation heat transfer and convection. The radiation analysis serves to develop a model that can be used in further work to gain a wider knowledge of the way in which the morphology of the fibrous material, i.e. fibre diameter distribution, fibre orientation distribution etc., influences the radiation heat transfer under different conditions. The convection investigation serves to examine whether considering convection as non-existent is a fair assumption to use in present and future building structures. The assumption applied in practically is that convection makes a notable difference only in very thick insulation, at external temperatures below -20 deg. C, and at very low densities. For lager thickness dimensions the resulting heat transfer through the fibrous material will be relatively small, which means that a relatively small increase in heat loss by convection may counterbalance part of the savings achieved by increasing the thickness. (au) 39 refs.

Dyrboel, Susanne

1998-05-01

278

40 CFR Appendix W to Part 51 - Guideline on Air Quality Models  

Science.gov (United States)

...Guideline on Air Quality Models Preface a. Industry and control...seriousness of potential air quality violations...correlation, frequency distribution, spatial extent...used to make an air pollution control...e., the design...

2010-07-01

279

40 CFR Appendix W to Part 51 - Guideline on Air Quality Models  

Science.gov (United States)

...that air quality control agencies...emission control requirements...Conference on Air Quality Modeling...deduce the statistical significance...potential air quality violations...about the statistical values should...pollution control decision....

2010-07-01

280

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2004-07-01

 
 
 
 
281

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

282

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)

283

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

Science.gov (United States)

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.

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

2014-10-01

284

Indicators to support the dynamic evaluation of air quality models  

Science.gov (United States)

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

Thunis, P.; Clappier, A.

2014-12-01

285

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

Directory of Open Access Journals (Sweden)

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.

Finnikov K.A.

2010-11-01

286

40 CFR Appendix W to Part 51 - Guideline on Air Quality Models  

Science.gov (United States)

...Quality Assurance for Air Pollution Measurement Systems...R-94/038d. Office of Air Quality Planning & Standards...490-9198 (automated request line) 96. Bowen, B...of a Solar Radiation/Delta-T (SRDT) Method for...R-93-055. Office of Air Quality Planning &...

2010-07-01

287

Testing theoretical models of magnetic damping using an air track  

CERN Document Server

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...

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

2007-01-01

288

Caenorhabditis elegans: a model to monitor bacterial air quality  

Directory of Open Access Journals (Sweden)

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.

Duclairoir Poc Cécile

2011-11-01

289

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

290

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.

291

Measurement and modelling of neon radiation profiles in radiating boundary discharges in ASDEX upgrade  

International Nuclear Information System (INIS)

The radiation and transport characteristics of ASDEX Upgrade discharges with a neon driven radiative mantle are modelled using a 1-D radial impurity transport code that has been coupled to a simple divertor model describing particle recycling and pumping. The code is well suited to describe the measured impurity line radiation, total, soft X-ray and bremsstrahlung radiation in regions of the plasma which are not dominated by two dimensional effects. The recycling and pumping behaviour of neon as well as the bulk transport of neon for radiative boundary scenarios are discussed. (orig.)

292

Measurement and modelling of neon radiation profiles in radiating boundary discharges in ASDEX Upgrade  

International Nuclear Information System (INIS)

The radiation and transport characteristics of ASDEX Upgrade discharges with a neon-driven radiative mantle are modelled using a one-dimensional radial impurity transport code that has been coupled to a simple divertor model describing particle recycling and pumping. The code is well suited to describing the measured impurity line radiation, total, soft x-ray and bremsstrahlung radiation in regions of the plasma that are not dominated by two-dimensional effects. The recycling and pumping behaviour of neon as well as the bulk transport of neon for radiative boundary scenarios are discussed. (Author)

293

Monitoring with a space-weather application the radiation doses received by air crews  

Science.gov (United States)

To fulfil new requirements of the European Community concerning monitoring of effective doses received by air crews, the French Aviation Authority has developed an operational system called SIEVERT. The SIEVERT system is analysed as an example of Space Weather application. Operational models will be used. As input to the models, the system needs monitoring of solar modulation of galactic cosmic rays and of solar flares. The French neutron monitors will be used for this purpose.

Lantos, P.

2002-03-01

294

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 precipitation explained 59% of the variation in the mean DOC concentration (F3,17= 8.29, p= 0.0013. Solar radiation and winter precipitation were correlated, negatively, while summer precipitation was correlated, positively, with DOC concentration. Because these relationships were based on only 21 years of data (1978 to 1998, the significance of the parameters in the regression model was evaluated with a randomisation test. This re-analysis indicated that summer precipitation did not contribute significantly to the regression model ( prand= 0.183. The final multiple regression explained 50% of the variation in DOC (F2,18 = 9.33, prand= 0.002 based on solar radiation and winter precipitation. These results suggest that solar radiation and winter precipitation have a significant role in determining long-term DOC concentration in boreal lakes. Keywords: dissolved-organic-carbon, lakes, climate, solar-radiation, precipitation, acid-precipitation, Precambrian-Shield-Ontario

J. J. Hudson

2003-01-01

295

Quantum statistical proposal for non-equilibrium shock layer radiation modeling  

Science.gov (United States)

The current objectives of the United States space program have instigated a renewed interest in the study of spacecraft atmospheric entry. This thesis introduces the concepts of radiative heating and the various mechanisms responsible for radiation emission and absorption. The three primary categories of radiation known as bound-bound, bound-free and free-free transitions are discussed in conjunction with the reaction rates and probabilities. Radiation models coupled with continuum and rarefied flowfield simulations are considered and common approximations are analyzed with respect to their varying degree of accuracy and efficiency. Select models are employed in an effort to compare theoretical radiative spectra and heat flux with experimental data at the same conditions collected from the Fire II and Apollo 4 flight tests. The basic concepts and configurations of shock tube facilities are presented in addition to the current issues and challenges associated with ground-based radiation testing. The main purpose of this thesis is to demonstrate the necessity for a novel approach to modeling radiation mechanisms in order to more accurately predict the integrated radiative heat flux incident on a spacecraft during lunar and Mars return trajectories. First, a sensitivity study is conducted for various input parameters into a computational fluid dynamics simulation and radiation model. The details of quantum statistical mechanics are outlined and exhibited in the form of radiation properties for both diatomic and atomic air species. Lastly, it is shown that plasma effects exist within hypersonic shock layers and may lead to important physical phenomena that substantially influence radiation mechanisms.

Calvert, Nathan D.

296

Radiation transport in earth for neutron and gamma ray point sources above an air-ground interface  

International Nuclear Information System (INIS)

Two-dimensional discrete ordinates methods were used to calculate the instantaneous dose rate in silicon and neutron and gamma ray fluences as a function of depth in earth from point sources at various heights (1.0, 61.3, and 731.5 meters) above an air--ground interface. The radiation incident on the earth's surface was transported through an earth-only and an earth--concrete model containing 0.9 meters of borated concrete beginning 0.5 meters below the earth's surface to obtain fluence distributions to a depth of 3.0 meters. The inclusion of borated concrete did not significantly reduce the total instantaneous dose rate in silicon and, in all cases, the secondary gamma ray fluence and corresponding dose are substantially larger than the primary neutron fluence and corresponding dose for depths greater than 0.6 meter. 4 figures, 4 tables

297

Model sensitivity and uncertainty analysis using roadside air quality measurements  

Energy Technology Data Exchange (ETDEWEB)

Most of the air quality modelling work has been so far oriented towards deterministic simulations of ambient pollutant concentrations. This traditional approach, which is based on the use of one selected model and one data set of discrete input values, does not reflect the uncertainties due to errors in model formulation and input data. Given the complexities of urban environments and the inherent limitations of mathematical modelling, it is unlikely that a single model based on routinely available meteorological and emission data will give satisfactory short-term predictions. In this study, different methods involving the use of more than one dispersion model, in association with different emission simulation methodologies and meteorological data sets, were explored for predicting best CO and benzene estimates, and related confidence bounds. The different approaches were tested using experimental data obtained during intensive monitoring campaigns in busy street canyons in Paris, France. Three relative simple dispersion models (STREET, OSPM and AEOLIUS) that are likely to be used for regulatory purposes were selected for this application. A sensitivity analysis was conducted in order to identify internal model parameters that might significantly affect results. Finally, a probabilistic methodology for assessing urban air quality was proposed. (author)

Vardoulakis, S. [Parc Technologie ALATA, Verneuil-en-Halatte (France). INERIS; University of Greenwich, London (United Kingdom). School of Computing and Mathematical Sciences; Fisher, B.E.A. [Environment Agency, Reading (United Kingdom). National Centre for Risk Analysis and Options; Gonzalez-Flesca, N. [Parc Technologie ALATA, Verneuil-en-Halatte (France). INERIS; Pericleous, K. [University of Greenwich, London (United Kingdom). School of Computing and Mathematical Sciences

2002-05-01

298

A simplified calibrated model for estimating daily global solar radiation in Madinah, Saudi Arabia  

Science.gov (United States)

Solar radiation is the most important parameter in defining the energy budget at the surface thereby influencing the hydroclimate. Several empirical models based on air temperature are developed and used in several decision-making needs such as agriculture and energy sector. However, a calibration against direct observations is a priori for implementing such models. A calibrated model is developed for Saudi Arabia (Madinah) based on observations during 2007-2011. The model is used to estimate daily solar radiation and results show a correlation coefficient of 0.94. The calibrated model outperforms the uncalibrated model available for this location. To increase the confidence, the calibrated model is also compared with a simple artificial neural network.

Benghanem, M.; Mellit, A.

2014-01-01

299

ANN-based modelling and estimation of daily global solar radiation data: A case study  

International Nuclear Information System (INIS)

In this paper, an artificial neural network (ANN) models for estimating and modelling of daily global solar radiation have been developed. The data used in this work are the global irradiation HG, diffuse irradiation HD, air temperature T and relative humidity Hu. These data are available from 1998 to 2002 at the National Renewable Energy Laboratory (NREL) website. We have developed six ANN-models by using different combination as inputs: the air temperature, relative humidity, sunshine duration and the day of year. For each model, the output is the daily global solar radiation. Firstly, a set of 4 x 365 points (4 years) has been used for training each networks, while a set of 365 points (1 year) has been used for testing and validating the ANN-models. It was found that the model using sunshine duration and air temperature as inputs, gives good accurate results since the correlation coefficient is 97.65%. A comparative study between developed ANN-models and conventional regression models is presented in this study.

300

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

International Nuclear Information System (INIS)

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

 
 
 
 
301

Heat radiation vs air drying to remove interfacial water from self-etch adhesives.  

Science.gov (United States)

The clinician's quest for time-saving and technique-insensitive technology has led to the development of simplified self-etch adhesives that are predominantly water or solvent based. Several studies have shown that conventional air-drying procedures are incapable of eliminating all the residual water in the adhesive and that it may even cause collapse of the underlying collagen matrix. We hypothesized that heat from a light source may be effective in removing water from these adhesives. The aim of this study was, therefore, to evaluate the effectiveness of heat vs conventional air drying in eliminating water droplets from self-etch adhesive. A self-etch adhesive was applied to bur-cut dentin surfaces, which were then allotted to one of two treatment procedures for eliminating residual water from the adhesive: conventional air drying or the experimental heat application. Specimens were then prepared and analyzed using SEM. Specimens in the experimental group showed no evidence of water treeing within the adhesive layer. Thus, it was concluded that heat radiation was an effective method to remove residual water from simplified adhesives. PMID:18445933

Mathews, Irene Elza; Arathi, G; Balagopal, S

2008-01-01

302

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

Science.gov (United States)

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

Kim, Y. J.; Noh, Y. M.; Song, C. H.; Yoon, S. C.; Han, J. S.

2009-03-01

303

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

Energy Technology Data Exchange (ETDEWEB)

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)

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

304

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

International Nuclear Information System (INIS)

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

305

Heat radiation vs air drying to remove interfacial water from self-etch adhesives  

Directory of Open Access Journals (Sweden)

Full Text Available The clinician?s quest for time-saving and technique-insensitive technology has led to the development of simplified self-etch adhesives that are predominantly water or solvent based. Several studies have shown that conventional air-drying procedures are incapable of eliminating all the residual water in the adhesive and that it may even cause collapse of the underlying collagen matrix. We hypothesized that heat from a light source may be effective in removing water from these adhesives. The aim of this study was, therefore, to evaluate the effectiveness of heat vs conventional air drying in eliminating water droplets from self-etch adhesive. A self-etch adhesive was applied to bur-cut dentin surfaces, which were then allotted to one of two treatment procedures for eliminating residual water from the adhesive: conventional air drying or the experimental heat application. Specimens were then prepared and analyzed using SEM. Specimens in the experimental group showed no evidence of water treeing within the adhesive layer. Thus, it was concluded that heat radiation was an effective method to remove residual water from simplified adhesives.

Mathews Irene

2008-01-01

306

Estimation of Global Solar Radiation in Rwanda Using Empirical Models  

Directory of Open Access Journals (Sweden)

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

B. Safari

2009-01-01

307

An analytical air pollution model: development and evaluation  

Energy Technology Data Exchange (ETDEWEB)

An analytical air quality dispersion model based on a discretization of the planetary boundary layer in N sublayers is presented. In each sublayer the diffusion-advection equation is solved by the Laplace transform techniques, considering an average value for the vertical exchange coefficient and the wind speed. This approach allows us to conjugate the advantages of the dispersion models based on analytical solutions and the more realistic wind and eddy diffusivity profiles related to a progress in the understanding of the planetary boundary layer structure. The model`s performances have been evaluated using the well-known Copenhagen dataset as well as the analytical model evaluating ground level concentrations from elevated sources (Tirabassi and Rizza, 1994). Then, the application of the statistical evaluation procedure (Hanna, 1989) over the outcoming results has shown that the proposed analytical dispersion model produces a good fitting of the observational data. (orig.) 13 refs.

Vilhena de, M.T.; Moreira, D.M. [Univ. Federale de Rio Grande do Sul, Porto Alegre (Brazil); Rizza, U.; Degrazia, G.A.; Mangia, C.; Tirabassi, T.

1998-08-01

308

A simplified model for air dehumidification with liquid desiccant  

Energy Technology Data Exchange (ETDEWEB)

This paper describes a relatively simple model for the preliminary design of an air dehumidification process occurring in a packed bed using liquid desiccant through dimensionless vapor pressure and temperature difference ratios. An expression is derived using the aforementioned ratios 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, with very good agreement. The effects of the cooling water inlet temperature and the desiccant-to-water heat exchanger effectiveness on the performance of the dehumidifier are also studied and the results are presented in this paper. (author)

Gandhidasan, P. [King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia). Department of Mechanical Engineering

2004-04-01

309

Seine estuary modelling and AirSWOT measurements validation  

Science.gov (United States)

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

Chevalier, Laetitia; Lyard, Florent; Laignel, Benoit

2013-04-01

310

Alpha and gamma radiation effects on air-water systems at high gas/liquid ratios  

International Nuclear Information System (INIS)

Radiolysis tests were conducted on air-water systems to examine the effects of radiation on liquid phase chemistry under high gas/liquid volume (G/L) ratios that are characteristic of an unsaturated nuclear waste repository setting. Test parameters included temperatures of 25, 90, and 200 degrees C; gamma vs. alpha radiation; dose rates of ?3500 and 50,000 rad/h; and G/L ratios of 10 and 100. Formate, oxalate, and total organic carbon contents increased during irradiation of the air-water systems in gamma and alpha tests at low-dose rate (?3500 rad/h). Increases in organic components were not observed for tests run at 200 degrees C or high-dose rates (50,000 rad/h). In the tests where increases in organics occurred, the formate and oxalate were preferentially enriched in solutions that were rinsed from the test vessel walls. Nitrate (NO3-) is the dominant anion produced during the radiolysis reactions. Significant nitrite (NO2-) also occurs in some high-dose rate tests, with the reduced form of nitrogen possibly resulting from reactions with the test vessels. These results indicate that nitrogen acids are being produced and concentrated in the limited quantities of solution present in the tests. Nitrate + nitrite production varied inversely with temperature, with the lowest quantities being detected for the higher temperature tests. The G(NO3- + NO2-) values for the 25, 90, and 200 degrees C experiments with gamma radiation are 3.2 ± 0.7, 1.3 ± 1.0, and 0.4 ± 0.3, respectively. Thus, the elevated temperatures expected early in the life of a repository may counteract pH decreases resulting from nitrogen acid production. Little variation was observed in G values as a function of dose rate or gas/liquid ratio

311

A simple model for biological effects of mixed radiations  

International Nuclear Information System (INIS)

A simple model is being developed for biological effects of mixed radiations based on the following two assumptions: 1) There exists a stage in the chain of radiation inactivation events when lesions produced by different radiations become identical, and hence additive, to produce the end-point observed. 2) The process that leads to the above additive lesion stage is relatively slow such that fast sequential irradiations can be considered equivalent to simultaneous irradiations. A linear dose isobologoram relationship can be derived from the above assumptions and can be shown to be able to explain many of the mixed radiation results published in the literature for a large variety of radiations of different LET. However, the model is strictly for mixed radiations only. The additive lesion concept is actually compatible with many of the standard radiation inactivation models

312

Improving ammonia emissions in air quality modelling for France  

Science.gov (United States)

We have implemented a new module to improve the representation of ammonia emissions from agricultural activities in France with the objective to evaluate the impact of such emissions on the formation of particulate matter modelled with the air quality model CHIMERE. A novel method has been set up for the part of ammonia emissions originating from mineral fertilizer spreading. They are calculated using the one dimensional 1D mechanistic model “VOLT'AIR” which has been coupled with data on agricultural practices, meteorology and soil properties obtained at high spatial resolution (cantonal level). These emissions display high spatiotemporal variations depending on soil pH, rates and dates of fertilization and meteorological variables, especially soil temperature. The emissions from other agricultural sources (animal housing, manure storage and organic manure spreading) are calculated using the national spatialised inventory (INS) recently developed in France. The comparison of the total ammonia emissions estimated with the new approach VOLT'AIR_INS with the standard emissions provided by EMEP (European Monitoring and Evaluation Programme) used currently in the CHIMERE model shows significant differences in the spatiotemporal distributions. The implementation of new ammonia emissions in the CHIMERE model has a limited impact on ammonium nitrate aerosol concentrations which only increase at most by 10% on the average for the considered spring period but this impact can be more significant for specific pollution episodes. The comparison of modelled PM10 (particulate matter with aerodynamic diameter smaller than 10 ?m) and ammonium nitrate aerosol with observations shows that the use of the new ammonia emission method slightly improves the spatiotemporal correlation in certain regions and reduces the negative bias on average by 1 ?g m-3. The formation of ammonium nitrate aerosol depends not only on ammonia concentrations but also on nitric acid availability, which is often a limiting factor in rural regions in France, and on meteorological conditions. The presented approach of ammonia emission calculation seems suitable for use in chemistry-transport models.

Hamaoui-Laguel, Lynda; Meleux, Frédérik; Beekmann, Matthias; Bessagnet, Bertrand; Génermont, Sophie; Cellier, Pierre; Létinois, Laurent

2014-08-01

313

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

Science.gov (United States)

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

314

The radiation disorder model of phase stability  

International Nuclear Information System (INIS)

A detailed theory is presented for radiation induced order-disorder phase transformations. Both radiation enhanced ordering and radiation induced disordering are described and the temperature and radiation rate dependent balance between them is obtained. The theory is applied to the case of Cu3Au. The free energy of partially or completely disordered phases is then calculated so that radiation modified phase diagrams can be determined. Such diagrams are presented for Ti-Co, Nb-Rh and Ti-Ru systems. Several experimental observations of phase instabilities are explained on the basis of the theory. (orig.)

315

Experimental analysis of airtightness and estimation of building air infiltration using two different single zone air infiltration models  

Directory of Open Access Journals (Sweden)

Full Text Available Building air leakage can contribute significantly to the energy consumption of a building. This paper presents the airtightness performance of a campus building located in Ontario, Canada. The air leakage rate through the building envelope was measured under stilted depressurization conditions following the ASTM E-779 standardized test method. With this test derived empirical leakage flow co-efficient and leakage flow exponent measures, the air infiltration rate for the building under varying wind and outside temperature conditions was calculated using two different single zone air infiltration models – the Lawrence Berkeley Laboratory model and the Alberta Air Infiltration model thus also allowing for a comparison of the results between the two mathematical models.

Tijo Joseph, Animesh Dutta

2014-01-01

316

CFD model of air movement in ventilated facade: comparison between natural and forced air flow  

Energy Technology Data Exchange (ETDEWEB)

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

Mora Perez, Miguel; Lopez Patino, Gonzalo; Lopez Jimenez, P. Amparo [Hydraulic and Environmental Engineering Department, Universitat Politècnica de Valencia (Spain)

2013-07-01

317

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)

Full Text Available SciELO Colombia | Language: Spanish Abstract in spanish 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.

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

2011-02-01

318

Numerical analysis of radiation effects in a metallic foam by means of the radiative conductivity model  

International Nuclear Information System (INIS)

The aim of this work is the evaluation of the radiation contribution to the steady-state heat transfer in metallic foams by means of the radiative conductivity model. Because of the complexity of the structure, reference is made to a simplified physical radiative model, where the elementary cell of the foams is treated as a cubic cell. The contribution of the radiation heat transfer is investigated on a local basis. The local radiative conductivity has been used to evaluate the influence of radiative heat transfer in a two dimensional conductive-convective-radiative problem involving a forced fluid flow within a heated channel filled with a metallic foam. The effect of the solid emissivity and the foam porosity is pointed out for different foams.

319

The air quality forecast in Beijing with Community Multi-scale Air Quality Modeling (CMAQ) System: model evaluation and improvement  

Science.gov (United States)

The MM5-SMOKE-CMAQ model system, which is developed by the United States Environmental Protection Agency(U.S. EPA) as the Models-3 system, has been used for the daily air quality forecast in the Beijing Municipal Environmental Monitoring Center(Beijing MEMC), as a part of the Ensemble Air Quality Forecast System for Beijing(EMS-Beijing) since the Olympic Games year 2008. In this study, we collect the daily forecast results of the CMAQ model in the whole year 2010 for the model evaluation. The results show that the model play a good model performance in most days but underestimate obviously in some air pollution episode. A typical air pollution episode from 11st - 20th January 2010 was chosen, which the air pollution index(API) of particulate matter (PM10) observed by Beijing MEMC reaches to 180 while the prediction of PM10-API is about 100. Taking in account all stations in Beijing, including urban and suburban stations, three numerical methods are used for model improvement: firstly, enhance the inner domain with 4km grids, the coverage from only Beijing to the area including its surrounding cities; secondly, update the Beijing stationary area emission inventory, from statistical county-level to village-town level, that would provide more detail spatial informance for area emissions; thirdly, add some industrial points emission in Beijing's surrounding cities, the latter two are both the improvement of emission. As the result, the peak of the nine national standard stations averaged PM10-API, which is simulated by CMAQ as daily hindcast PM10-API, reach to 160 and much near to the observation. The new results show better model performance, which the correlation coefficent is 0.93 in national standard stations average and 0.84 in all stations, the relative error is 15.7% in national standard stations averaged and 27% in all stations. The time series of 9 national standard in Beijing urban The scatter diagram of all stations in Beijing, the red is the forecast and the blue is new result.

Wu, Q.

2013-12-01

320

Modeling of external radiation from the transport of radionuclides across a canyon  

International Nuclear Information System (INIS)

The Los Alamos Meson Physics Facility (LAMPF) is an 800-million electron volt, l mA intensity linear proton accelerator used for studying subatomic particles at relativistic velocities. Routine operation of the accelerator results in the formation of short-lived air activation products, primarily in the beam stop section of LAMPF. This study presents the results of monitoring and modeling external radiation levels from LAMPF emissions at three locations during 1984. Measured radiation exposures are presented for all three locations during a 49-day period. Hourly radiation levels are calculated for all sites and compared with the prevalent wind patterns during the study period. Predicted daily levels are compared with measured values at all of the sites. Accuracy of the model is compared for day and night conditions. Annual model predictions are also compared with TLD measurements

 
 
 
 
321

Higgs inflation in a radiative seesaw model  

Energy Technology Data Exchange (ETDEWEB)

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 Z{sub 2}-odd isospin doublet scalar field and Z{sub 2}-odd right-handed neutrinos. We study the possibility that the Higgs boson as well as neutral components of the Z{sub 2}-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.

Kanemura, Shinya, E-mail: kanemu@sci.u-toyama.ac.jp; Matsui, Toshinori, E-mail: matsui@jodo.sci.u-toyama.ac.jp; Nabeshima, Takehiro, E-mail: nabe@jodo.sci.u-toyama.ac.jp

2013-06-10

322

Higgs inflation in a radiative seesaw model  

CERN Document Server

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 Ma in order to explain neutrino masses and dark matter by introducing a $Z_2$-odd isospin doublet scalar field and $Z_2$-odd right-handed neutrinos. We study the possibility that the Higgs boson as well as neutral components of the $Z_2$-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.

Kanemura, Shinya; Nabeshima, Takehiro

2012-01-01

323

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

324

Radiative Symmetry Breaking in Brane Models  

CERN Document Server

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 $\\tan\\beta$ and $m_A$. 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.

Antoniadis, Ignatios; Quirós, Mariano

2000-01-01

325

Atmospheric radiative transfer modeling: a summary of the AER codes  

Energy Technology Data Exchange (ETDEWEB)

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{sub L}W and RRTM{sub S}W; the Monochromatic Radiative Transfer Model (MonoRTM); the MT{sub C}KD 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.

Clough, S.A. [Atmospheric and Environmental Research (AER) Inc., 131 Hartwell Avenue, Lexington, MA 02421-3126 (United States); Shephard, M.W. [Atmospheric and Environmental Research (AER) Inc., 131 Hartwell Avenue, Lexington, MA 02421-3126 (United States)]. E-mail: mshephar@aer.com; Mlawer, E.J. [Atmospheric and Environmental Research (AER) Inc., 131 Hartwell Avenue, Lexington, MA 02421-3126 (United States); Delamere, J.S. [Atmospheric and Environmental Research (AER) Inc., 131 Hartwell Avenue, Lexington, MA 02421-3126 (United States); Iacono, M.J. [Atmospheric and Environmental Research (AER) Inc., 131 Hartwell Avenue, Lexington, MA 02421-3126 (United States); Cady-Pereira, K. [Atmospheric and Environmental Research (AER) Inc., 131 Hartwell Avenue, Lexington, MA 02421-3126 (United States); Boukabara, S. [Atmospheric and Environmental Research (AER) Inc., 131 Hartwell Avenue, Lexington, MA 02421-3126 (United States); Brown, P.D. [Atmospheric and Environmental Research (AER) Inc., 131 Hartwell Avenue, Lexington, MA 02421-3126 (United States)

2005-03-01

326

A Multi-layer Radiation Model for Urban Neighbourhoods with Trees  

Science.gov (United States)

A neighbourhood-scale multi-layer urban canopy model of shortwave and longwave radiation exchange that explicitly includes the radiative effects of tall vegetation (trees) is presented. Tree foliage is permitted both between and above buildings, and mutual shading, emission and reflection between buildings and trees are included. The basic geometry is a two-dimensional canyon with leaf area density profiles and probabilistic variation of building height. Furthermore, the model accounts for three-dimensional path lengths through the foliage. Ray tracing determines the receipt of direct shortwave irradiance by building and foliage elements. View factors for longwave and shortwave diffuse radiation exchange are computed once at the start of the simulation using a Monte Carlo ray tracing approach; for subsequent model timesteps, matrix inversion rapidly solves infinite reflections and interception of emitted longwave between all elements. The model is designed to simulate any combination of shortwave and longwave radiation frequency bands, and to be portable to any neighbourhood-scale urban canopy geometry based on the urban canyon. Additionally, the model is sufficiently flexible to represent forest and forest-clearing scenarios. Model sensitivity tests demonstrate the model is robust and computationally feasible, and highlight the importance of vertical resolution to the performance of urban canopy radiation models. Full model evaluation is limited by the paucity of within-canyon radiation measurements in urban neighbourhoods with trees. Where appropriate model components are tested against analytic relations and results from an independent urban radiation transfer model. Furthermore, system response tests demonstrate the ability of the model to realistically distribute shortwave radiation among urban elements as a function of built form, solar angle and tree foliage height, density and clumping. Separate modelling of photosynthetically-active and near-infrared shortwave bands is shown to be important in some cases. Increased canyon height-to-width ratio and/or tree cover diminishes the net longwave radiation loss of individual canyon elements (e.g., floor, walls), but, notably, has little effect on the net longwave loss of the whole urban canopy. When combined with parametrizations for the impacts of trees on airflow and hydrological processes in the urban surface layer, the new radiation model extends the applicability of urban canopy models and permits more robust assessment of trees as tools to manage urban climate, air quality, human comfort and building energy loads.

Krayenhoff, E. S.; Christen, A.; Martilli, A.; Oke, T. R.

2014-04-01

327

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)

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.

Underwood, Lauren; Ryan, Robert E.

2007-01-01

328

Discrete-Choice Models and Their Application to Air Transportation  

Directory of Open Access Journals (Sweden)

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

Marina Ciarlini

2008-01-01

329

40 CFR Appendix W to Part 51 - Guideline on Air Quality Models  

Science.gov (United States)

...Dispersion Modeling: A Critical Review. Journal of the Air Pollution Control Association...and Boundary Layer Characterization. Journal of Applied Meteorology , 44(5...plume rise and building downwash model. Journal of the Air & Waste Management...

2010-07-01

330

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...

331

Sunspot Modeling: From Simplified Models to Radiative MHD Simulations  

Directory of Open Access Journals (Sweden)

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.

Rolf Schlichenmaier

2011-09-01

332

3D Atmospheric Radiative Transfer for Cloud System-Resolving Models: Forward Modelling and Observations  

Energy Technology Data Exchange (ETDEWEB)

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.

Howard Barker; Jason Cole

2012-05-17

333

Modelling of Radiation Heat Transfer in Reacting Hot Gas Flows  

Science.gov (United States)

In this work the interaction between a turbulent flow including chemical reactions and radiation transport is investigated. As a first step, the state-of-the art radiation models P1 based on the moment method and Discrete Transfer Model (DTM) based on the discrete ordinate method are used in conjunction with the CFD code ANSYS CFX. The absorbing and emitting medium (water vapor) is modeled by Weighted Sum of Gray Gases. For the chemical reactions the standard Eddy dissipation model combined with the two equation turbulence model k-epsilon is employed. A demonstration experiment is identified which delivers temperature distribution, species concentration and radiative intensity distribution in the investigated combustion enclosure. The simulation results are compared with the experiment and reveals that the P1 model predicts the location of the maximal radiation intensity unphysically. On the other hand the DTM model does better but over predicts the maximum value of the radiation intensity. This radiation sensitivity study is a first step on the way to identify a suitable radiation transport and spectral model in order to implement both in an existing 3D Navier-Stokes Code. Including radiation heat transfer we intend to investigate the influence on the overall energy balance in a hydrogen/oxygen rocket combustion chamber.

Thellmann, A.; Mundt, C.

2009-01-01

334

Testing theoretical models of magnetic damping using an air track  

Energy Technology Data Exchange (ETDEWEB)

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.

Vidaurre, Ana; Riera, Jaime; Monsoriu, Juan A; Gimenez, Marcos H [Department of Applied Physics, Polytechnic University of Valencia, E-46022 Valencia (Spain)], E-mail: vidaurre@fis.upv.es

2008-03-12

335

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

336

Methodology for modeling the microbial contamination of air filters.  

Science.gov (United States)

In this paper, we propose a theoretical model to simulate microbial growth on contaminated air filters and entrainment of bioaerosols from the filters to an indoor environment. Air filter filtration and antimicrobial efficiencies, and effects of dust particles on these efficiencies, were evaluated. The number of bioaerosols downstream of the filter could be characterized according to three phases: initial, transitional, and stationary. In the initial phase, the number was determined by filtration efficiency, the concentration of dust particles entering the filter, and the flow rate. During the transitional phase, the number of bioaerosols gradually increased up to the stationary phase, at which point no further increase was observed. The antimicrobial efficiency and flow rate were the dominant parameters affecting the number of bioaerosols downstream of the filter in the transitional and stationary phase, respectively. It was found that the nutrient fraction of dust particles entering the filter caused a significant change in the number of bioaerosols in both the transitional and stationary phases. The proposed model would be a solution for predicting the air filter life cycle in terms of microbiological activity by simulating the microbial contamination of the filter. PMID:24523908

Joe, Yun Haeng; Yoon, Ki Young; Hwang, Jungho

2014-01-01

337

On the role of ventilation and air clean-up in the radiation safety ensurance for NPPs with WWER-1000  

International Nuclear Information System (INIS)

The main radiation hygiene principles are considered for ventilation of NPPs with WWER-1000 with airtight shell as well as the design solutions for the ventilation and air clean-up systems of the reactor premises. On the basis of the major gas and aerosol radiation release sources assessment and experience of Novo Voronezh NPP 5-th unit operation the efficiency of the ventilation and air clean-up systems design has been demonstrated from the viewpoint of the personnel safety and impact on the environment

338

A Mars Dust Model with Interactive Dynamics, Radiation and Microphysics  

Science.gov (United States)

Radiatively active dust particles suspended in the martian atmosphere impact atmospheric thermodynamics and circulation. We show results from the NCAR Community Atmosphere Model for Mars coupled with CARMA to create a fully interactive dust model.

Hartwick, V. L.; Toon, O. B.

2014-07-01

339

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)

340

The dynamic test modeling of the air-operated valve  

International Nuclear Information System (INIS)

The prediction of AOV(Air-Operated Valve) performance is normally evaluated by the allowable operating thrust/torque margin for the opening and closing strokes. However, it is not easy to carry out the dynamic test measurement for all the valves in the nuclear power plant due to the safety and operating conditions. The analysis of the available and required thrust/torque for the valve is considered as the alternate method to turn around this obstacle. This paper discusses the dynamic modeling and the simulation for the diaphragm type air operated globe valve. The pressure difference is assumed as two kinds of variation - linear and curved shape- when the valve is opened or closed. SIMULINK in MATLAB was used for the simulation and the results show good agreement with the actual test done by previous research

 
 
 
 
341

Computer modelling of radiation-induced bystander effect  

International Nuclear Information System (INIS)

Radiation-induced genomic instability and bystander effects are now well established consequences of exposure of living cells to ionising radiation. It has been observed that cells not directly hit by radiation tracks may still exhibit radiation effects. We present a quantitative modelling of the radiation-induced bystander effect based on a diffusion model of spreading the bystander signal. The model assumes the bystander factor to be a protein of low molecular weight, given out by the hit cell, diffusing in the medium and reacting with non-hit cells. The model calculations successfully predict the results of cell survival in an irradiated conditioned medium. The model predicts the shape of dose-effect relationship for cell survival and oncogenic transformation induced by broad-beam and micro-beam irradiation by alpha-particles. (author)

342

Comparison of photochemical mechanisms for air quality modeling  

Science.gov (United States)

Photochemical mechanisms are a critical module of air quality models. In the past 20 years, several mechanisms have been developed to study the chemistry of the troposphere. This work compares several state-of-the-science photochemical mechanisms (including LCC, CBM-IV, RADM2, EMEP, RACM, SAPRC99, and CACM which have never been compared before in other studies). Concise descriptions of the chemical schemes are included. The main difference among existing mechanisms is the lumping technique used to classify organic compounds into surrogate groups. First, box model calculations are conducted to highlight the features that lead to differences in the modeled behaviors of photochemical pollutants and their precursors. Results indicate that most chemical schemes yield similar ozone concentrations. Nevertheless, there are significant discrepancies, mainly in predicted concentration of HNO 3, HO 2 and total PAN among model simulations. Finally, the sources of the discrepancy are identified.

Jimenez, Pedro; Baldasano, Jose M.; Dabdub, Donald

343

76 FR 62605 - Airworthiness Directives; Viking Air Limited Model DHC-3 (Otter) Airplanes With Supplemental Type...  

Science.gov (United States)

...Directives; Viking Air Limited Model DHC-3 (Otter) Airplanes With Supplemental Type Certificate...applies to Viking Air Limited Model DHC-3 (Otter) airplanes equipped with a Honeywell TPE331...for Viking Air Limited Model DHC-3 (Otter) airplanes equipped with a Honeywell...

2011-10-11

344

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

345

A method for natural background gamma radiation measurement using air-equivalent scintillation detector  

International Nuclear Information System (INIS)

A method and a complete set of instruments are developed for measuring natural bachground gamma radiations using air-equivalent scintillation detectors - polystyrol with addition of silver activied zinx sulfide with effective atomic number 7.64. The detector is completed with a scintillation head, type VA-S-968, and one-channel analyser, type 20026. The callibrating coefficient relative to 226Ra is average 5.0x1014kg.A-1 x min-1. During measurement lasting 20 min, a 10 per cent alteration in the gamma background is registered with statistical error less than 20 per cent. The experimentally estimated registration efficacy dependence on the gamma quanta energy does not exceed +- 17 per cent. The counting statistics lends itself to further improvement by measurement time prolongation. (author)

346

Radiation safety of the helicopter air crow-liquidators of the Chernobyl NPP accident  

International Nuclear Information System (INIS)

Three aspects of the radiation safety of the helicopter air crew who took part in the elimination of the Chernobyl NPP accident after-effects during the period from the 27-th of April to July 1986 were considered: dosimetry, physical protection and radioprotector use. 1125 subjects from the flight and engineer personnel were irradiated: 6%-2.5 mSv and more, 32%-2.1-2.5 mSv and about 60% - up to 2.0 mSv. It is stated that the use of physical protection (local screening of a pilot seat and use of special antiradiation belts) makes irradiation doe 2-3 times less. In the intense conditions of flight activity the pilots preferred the radioprotector adrenaline to cystamin. Alimentary aids in the earlier and later periods after the accident influenced favourably somatic and psychic states. 16 refs.; 1 tab

347

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

348

Computer modelling of statistical properties of SASE FEL radiation  

International Nuclear Information System (INIS)

The paper describes an approach to computer modelling of statistical properties of the radiation from self amplified spontaneous emission free electron laser (SASE FEL). The present approach allows one to calculate the following statistical properties of the SASE FEL radiation: time and spectral field correlation functions, distribution of the fluctuations of the instantaneous radiation power, distribution of the energy in the electron bunch, distribution of the radiation energy after monochromator installed at the FEL amplifier exit and the radiation spectrum. All numerical results presented in the paper have been calculated for the 70 nm SASE FEL at the TESLA Test Facility being under construction at DESY

349

Comparisons of the radiation protection standards for air kerma of the NIST and the BIPM for 60Co and 137Cs gamma radiation  

International Nuclear Information System (INIS)

An indirect comparison of the standards for air kerma of the National Institute of Standards and Technology (NIST), USA, and of the Bureau International des Poids et Mesures (BIPM) was carried out in the 60Co and 137Cs radiation protection-level beams of the BIPM in September 2011. The comparison results, based on the calibration coefficient for two transfer standards and expressed as a ratio of the NIST and the BIPM standards for air kerma, are 1.0023 with a combined standard uncertainty of 3.2 * 10-3 in 60Co, and 0.9990 with a combined standard uncertainty of 3.5 * 10-3 in 137Cs. The result in the 60Co beam for radiation protection agrees within the uncertainties with the result of the comparison carried out at the same time in the CIS Bio 60Co beam for radiotherapy-level air kerma. (authors)

350

Subgrid-scale model for radiative transfer in turbulent participating media  

International Nuclear Information System (INIS)

The simulation of turbulent flows of radiating gases, taking into account all turbulence length scales with an accurate radiation transport solver, is computationally prohibitive for high Reynolds or Rayleigh numbers. This is particularly the case when the small structures are not optically thin. We develop in this paper a radiative transfer subgrid model suitable for the coupling with direct numerical simulations of turbulent radiating fluid flows. Owing to the linearity of the Radiative Transfer Equation (RTE), the emission source term is spatially filtered to define large-scale and subgrid-scale radiation intensities. The large-scale or filtered intensity is computed with a standard ray tracing method on a coarse grid, and the subgrid intensity is obtained analytically (in Fourier space) from the Fourier transform of the subgrid emission source term. A huge saving of computational time is obtained in comparison with direct ray tracing applied on the fine mesh. Model accuracy is checked for three 3D fluctuating temperature fields. The first field is stochastically generated and allows us to discuss the effects of the filtering level and of the optical thicknesses of the whole medium, of the integral length scale, and of the cutoff wave length. The second and third cases correspond respectively to turbulent natural convection of humid air in a cubical box, and to the flow of hot combustion products inside a channel. In all cases, the achieved accuracy on radiative powers and wall fluxes is about a few percents

351

Subgrid-scale model for radiative transfer in turbulent participating media  

Science.gov (United States)

The simulation of turbulent flows of radiating gases, taking into account all turbulence length scales with an accurate radiation transport solver, is computationally prohibitive for high Reynolds or Rayleigh numbers. This is particularly the case when the small structures are not optically thin. We develop in this paper a radiative transfer subgrid model suitable for the coupling with direct numerical simulations of turbulent radiating fluid flows. Owing to the linearity of the Radiative Transfer Equation (RTE), the emission source term is spatially filtered to define large-scale and subgrid-scale radiation intensities. The large-scale or filtered intensity is computed with a standard ray tracing method on a coarse grid, and the subgrid intensity is obtained analytically (in Fourier space) from the Fourier transform of the subgrid emission source term. A huge saving of computational time is obtained in comparison with direct ray tracing applied on the fine mesh. Model accuracy is checked for three 3D fluctuating temperature fields. The first field is stochastically generated and allows us to discuss the effects of the filtering level and of the optical thicknesses of the whole medium, of the integral length scale, and of the cutoff wave length. The second and third cases correspond respectively to turbulent natural convection of humid air in a cubical box, and to the flow of hot combustion products inside a channel. In all cases, the achieved accuracy on radiative powers and wall fluxes is about a few percents.

Soucasse, L.; Rivière, Ph.; Soufiani, A.

2014-01-01

352

Testing models of new physics with UHE air shower observations  

CERN Document Server

Several air shower observatories have established that the number of muons produced in UHE air showers is significantly larger than that predicted by models. We argue that the only solution to this muon deficit, compatible with the observed Xmax distributions, is to reduce the transfer of energy from the hadronic shower into the EM shower, by reducing the production or decay of pi0s. We present four different models of new physics, each with a theoretical rationale, which can accomplish this. One has a pure proton composition and three have mixed composition. Two entail new particle physics and suppress pi0 production or decay above LHC energies. The other two are less radical but nonetheless require significant modifications to existing hadron production models -- in one the changes are only above LHC energies and in the other the changes extend to much lower energies. We show that the models have distinctively different predictions for the correlation between the number of muons at ground and Xmax in hybrid...

Allen, Jeffrey

2013-01-01

353

Urban air pollution modelling and measurements of boundary layer height  

Science.gov (United States)

An urban field trial has been undertaken with the aim of assessing the performance of the boundary layer height (BLH) determination of two models: the Met Office Unified Model (UM) and a Gaussian-type plume model, ADMS. Pulsed Doppler lidar data were used to measure mixing layer height and cloud base heights for a variety of meteorological conditions over a 3 week period in July 2003. In this work, the daily growth and decay of the BLH from the lidar data and model simulations for 5 days are compared. The results show that although the UM can do a good job of reproducing the boundary layer growth, there are occasions where the BLH is overestimated by 30-100%. Within dispersion models it is the BLH that effectively limits the height to which pollution disperses, so these results have very important implications for pollution dispersion modelling. The results show that correct development of the boundary layer in the UM is critically dependant on morning cloud cover. The ADMS model is used routinely by local authorities in the UK for local air-quality forecasting. The ADMS model was run under three settings; an 'urban' roughness, a 'rural' roughness and a 'transition' roughness. In all cases, the 'urban' setting over estimated the BLH and is clearly a poor predictor of urban BLH. The 'transition' setting, which distinguishes between the meteorological data input site and the dispersion modelling site, gave the best results under the well mixed conditions of the trial.

Davies, F.; Middleton, D. R.; Bozier, K. E.

354

LINKING ETA MODEL WITH THE COMMUNITY MULTISCALE AIR QUALITY (CMAQ) MODELING SYSTEM: OZONE BOUNDARY CONDITIONS  

Science.gov (United States)

A prototype surface ozone concentration forecasting model system for the Eastern U.S. has been developed. The model system is consisting of a regional meteorological and a regional air quality model. It demonstrated a strong prediction dependence on its ozone boundary conditions....

355

Environmental Radiation Effects on Mammals A Dynamical Modeling Approach  

CERN Document Server

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...

Smirnova, Olga A

2010-01-01

356

Research on Dependable Ionizing Radiation Protection based on Model i*  

Directory of Open Access Journals (Sweden)

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.

Tan Hai

2013-07-01

357

The variability of radiative balance elements and air temperature over the Asian region of Russia  

Directory of Open Access Journals (Sweden)

Full Text Available The variability of spatial-temporal distribution of temperature and heat balance elements is investigated for the Asian territory of Russia (45–80° N, 60–180° E using JRA-25, NCEP/DOE AMIP-II reanalysis data and observational data for the period of global warming 1979–2008. It is shown that temperature trend over the territory is 1.4 °C for the period under study according to reanalysis data. Since the beginning of 90s of 20th century the increase of back earth-atmosphere shortwave radiation is observed. Such tendency is in conformity with the cloud cover distribution and downward shortwave radiation at the surface. Regression model describing temperature variability with variability of heat balance elements was presented. We conclude that possible applications for the model include the convenient estimate of temperature variability according to reanalysis data.

E. V. Kharyutkina

2012-03-01

358

Gamma radiation exposure of air crew in Tehran-Bandarabbas flights  

International Nuclear Information System (INIS)

Different researches have been performed on natural exposure of cosmic rays and their effects on the human health. Monitoring of cosmic derived gamma ray exposure of air crews and passengers is the subject of the current study. In this paper, the control able variations of the cosmic ray flux in the atmosphere and the cosmic radiation exposure at flight altitudes will be discussed. For this study, the exposure rates to gamma ray, in an energy range of 50 keV-1.5 MeV, for the Tehran-Bandarabbas air flights have been measured. The results show that the maximum dose rate at 3000 ft (about 9 km) is 15-20 times higher than on the ground base. Also, the dose rate for this pathway is about 1.87?Sv/h which for 500 hours flights per year it is estimatal to be 935?Sv. This number is less than human permissible dose rate of 1 mSv/year.

359

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

360

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

Science.gov (United States)

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.

Guttikunda, Sarath K.; Jawahar, Puja

2012-12-01

 
 
 
 
361

X-ray radiation from the volume discharge in atmospheric-pressure air  

Science.gov (United States)

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.

Bratchikov, V. B.; Gagarinov, K. A.; Kostyrya, I. D.; Tarasenko, V. F.; Tkachev, A. N.; Yakovlenko, S. I.

2007-07-01

362

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

Directory of Open Access Journals (Sweden)

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.

Manoj J. Gundalia

2013-11-01

363

Quality criteria for air pollution models, standardisation and model development in the Netherlands  

International Nuclear Information System (INIS)

Based on standards of EPA and IEEE, quality criteria have been formulated which address the development of air pollution models, the transformation towards user-friendly software and ''after-sales'' service. A Dutch standard on the description of air pollution models is being finalized. The standard formulates minimal requirements on the theoretical and practical description of models. This paper provides a survey of the quality criteria and it summarizes the standard. Further, the current practice of model development at RIVM is discussed. (au) (24 refs.)

364

Evaluation of radiation scheme using offline code and global model  

Science.gov (United States)

Radiation is an important physical process in the atmosphere which determines horizontal and vertical thermal state through the absorption, reflection, and emission of solar and terrestrial radiation. Also, interactions between radiation, clouds, aerosols, and surface occur too complicatedly to understand. Representing these processes in the numerical weather prediction model or climate model is very challenging and numerous efforts have been made. In this study, the performance of Rapid Radiative Transfer Model for General Circulation Models (RRTMG) developed for the Global Forecasting System (GFS) and Community Earth System Model (CESM) were evaluated through the offline independently. Also, both RRTMG models were implemented to the Korea Institute of Atmospheric Systems' experimental 3D global model to assess their characteristics and performances, which will provide the basis of the development of better radiation parameterization scheme. Fluxes and atmospheric heating/cooling rates from each radiation scheme were compared and the differences were analyzed. The different treatments of clouds and surface properties caused the differences between two schemes. The possibilities of development of faster, more realistic, and more accurate radiation parameterization scheme were explored based on the comparison of model results.

LEE, J.; Jin, E.

2013-12-01

365

Cloud-precipitation-radiation-dynamics interaction in global climate models: A snow and radiation interaction sensitivity experiment  

Science.gov (United States)

global climate models (GCMs) often consider radiation interactions only with small-particle/suspended cloud mass, ignoring large-particle/falling and convective core cloud mass. We characterize the radiation and atmospheric circulation impacts of frozen precipitating hydrometeors (i.e., snow), using the National Center for Atmospheric Research coupled GCM, by conducting sensitivity experiments that turn off the radiation interaction with snow. The changes associated with the exclusion of precipitating hydrometeors exhibit a number differences consistent with biases in CMIP3 and CMIP5 (Coupled Model Intercomparison Project Phase 3 and Phase 5), including more outgoing longwave flux at the top of atmosphere and downward shortwave flux at the surface in the heavily precipitating regions. Neglecting the radiation interaction of snow increases the net radiative cooling near the cloud top with the resulting increased instability triggering more convection in the heavily precipitating regions of the tropics. In addition, the increased differential vertical heating leads to a weakening of the low-level mean flow and an apparent low-level eastward advection from the warm pool resulting in moisture convergence south of the Intertropical Convergence Zone and north of the South Pacific Convergence Zone (SPCZ). This westerly bias, with effective warm and moist air transport, might be a contributing factor in the model's northeastward overextension of the SPCZ and the concomitant changes in sea surface temperatures, upward motion, and precipitation. Broader dynamical impacts include a stronger local meridional overturning circulation over the middle and east Pacific and commensurate changes in low and upper level winds, large-scale ascending motion, with a notable similarity to the systematic bias in this region in CMIP5 upper level zonal winds.

Li, J.-L. F.; Lee, W.-L.; Waliser, D. E.; David Neelin, J.; Stachnik, Justin P.; Lee, Tong

2014-04-01

366

Modelling of the Through-air Bonding Process  

Directory of Open Access Journals (Sweden)

Full Text Available A computational fluid dynamics (CFD modelling ofthe through-air bonding process of nonwoven fabricproduction is reported in this article. In the throughairprocess, hot air is passed through the fibrous webto heat and melt polymer fibers. Molten polymersubsequently flows to the point of contact betweenany two fibers to produce a bond. Two differentmodelling strategies are adapted to produce acomprehensive understanding of the through-airbonding process. In macroscale modelling, a CFDmodel is developed treating the whole web as aporous media in order to investigate the effect ofprocess parameters. Results reveal that the timerequired to heat and melt the fibers decreases with theincreasing porosity of the web and the velocity of hotair. The CFD modelling technique is then used toanalyze the bonding process at a more fundamentallevel by considering the bonding of individual fibersat microscale. The effects of the fiber diameter,bonding temperature and contact angle between twofibers on the bonding time are investigated. Resultsshow that the time required to bond fibers is weaklyrelated to bonding temperature and fiber diameter.Fiber orientation angle, on the other hand, hassignificant effect on the progression of bondformation.

M. Hossain

2009-06-01

367

Spatial and energy distributions of skyshine neutron and gamma radiation from nuclear reactors on the ground-air boundary  

International Nuclear Information System (INIS)

A set of measurements on skyshine radiation was conducted at two special research reactors. A broad range of detectors was used in the measurements to record neutron and gamma radiations. Dosimetric and radiometric field measurements of the neutrons and gamma quanta of the radiation scattered in the air were performed at distances of 50 to 1000 m from the reactor during different weather conditions. The neutron spectra in the energy range of 1 eV to 10 MeV and the gamma quanta spectra in the range of 0.1-10 MeV were measured. (author)

368

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

CERN Document Server

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 ...

Métral, Claudine; Karatzas, Kostas

2012-01-01

369

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.)

370

Model air-supported drum-type homopolar generator  

International Nuclear Information System (INIS)

A single cylinder, drum-type homopolar generator has been designed and built for the purpose of developing a simple air support system for thin cylinder rotors operated at high surface velocities and significant radial drum growth. The model has an aluminum cylinder which is 0.32 cm thick, 25 cm in diameter, and 12.7 cm long. It is designed to operate at a peak current of 2500 A and to store a total of 40 kJ with a surface velocity of 305 m/sec

371

Model air-supported drum-type homopolar generator  

Energy Technology Data Exchange (ETDEWEB)

A single cylinder, drum-type homopolar generator has been designed and built for the purpose of developing a simple air support system for thin cylinder rotors operated at high surface velocities and significant radial drum growth. The model has an aluminum cylinder which is 0.32 cm thick, 25 cm in diameter, and 12.7 cm long. It is designed to operate at a peak current of 2500 A and to store a total of 40 kJ with a surface velocity of 305 m/sec.

Kustom, R. L.; Fuja, R. E.; Wehrle, R. B.; Smith, R. P.; Kovarik, T. J.

1977-01-01

372

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

Directory of Open Access Journals (Sweden)

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.

Vlad Isakov

2014-08-01

373

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

Science.gov (United States)

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. PMID:25166917

Isakov, Vlad; Arunachalam, Saravanan; Batterman, Stuart; Bereznicki, Sarah; Burke, Janet; Dionisio, Kathie; Garcia, Val; Heist, David; Perry, Steve; Snyder, Michelle; Vette, Alan

2014-01-01

374

Quantifying urban street configuration for improvements in air pollution models  

Science.gov (United States)

In many built-up urban areas, tall buildings along narrow streets obstruct the free flow of air, resulting in higher pollution levels. Input data to account for street configuration in models are difficult to obtain for large numbers of streets. We describe an approach to calculate indicators of this "urban canyon effect" using 3-dimensional building data and evaluated whether these indicators improved spatially resolved land use regression (LUR) models.Concentrations of NO2 and NOx were available from 132 sites in the Netherlands. We calculated four indicators for canyon effects at each site: (1) the maximum aspect ratio (building height/width of the street) between buildings on opposite sides of the street, (2) the mean building angle, which is the angle between the horizontal street level and the line of sight to the top of surrounding buildings, (3) median building angle and (4) "SkyView Factor" (SVF), a measure of the total fraction of visible sky. Basic LUR models were computed for both pollutants using common predictors such as household density, land-use and nearby traffic intensity. We added each of the four canyon indicators to the basic LUR models and evaluated whether they improved the model.The calculated aspect ratio agreed well (R2 = 0.49) with aspect ratios calculated from field observations. Explained variance (R2) of the basic LUR models without canyon indicators was 80% for NO2 and 76% for NOx, and increased to 82% and 78% respectively if SVF was included. Despite this small increase in R2, contrasts in SVF (10th-90th percentile) resulted in substantial concentration differences of 5.56 ?g m-3 in NO2 and 10.9 ?g m-3 in NOx.We demonstrated a GIS based approach to quantify the obstruction of free air flow by buildings, applicable for large numbers of streets. Canyon indicators could be valuable to consider in air pollution models, especially in areas with low- and high-rise canyons.

Eeftens, Marloes; Beekhuizen, Johan; Beelen, Rob; Wang, Meng; Vermeulen, Roel; Brunekreef, Bert; Huss, Anke; Hoek, Gerard

2013-06-01

375

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

376

Modeling Air Traffic Management Technologies with a Queuing Network Model of the National Airspace System  

Science.gov (United States)

This report describes an integrated model of air traffic management (ATM) tools under development in two National Aeronautics and Space Administration (NASA) programs -Terminal Area Productivity (TAP) and Advanced Air Transport Technologies (AATT). The model is made by adjusting parameters of LMINET, a queuing network model of the National Airspace System (NAS), which the Logistics Management Institute (LMI) developed for NASA. Operating LMINET with models of various combinations of TAP and AATT will give quantitative information about the effects of the tools on operations of the NAS. The costs of delays under different scenarios are calculated. An extension of Air Carrier Investment Model (ACIM) under ASAC developed by the Institute for NASA maps the technologies' impacts on NASA operations into cross-comparable benefits estimates for technologies and sets of technologies.

Long, Dou; Lee, David; Johnson, Jesse; Gaier, Eric; Kostiuk, Peter

1999-01-01

377

A kinetic model of radiating electrons  

Energy Technology Data Exchange (ETDEWEB)

A kinetic theory is developed to describe radiating electrons whose motion is governed by the Lorentz-Dirac equation. This gives rise to a generalized Vlasov equation coupled to an equation for the evolution of the physical submanifold of phase space. The pathological solutions of the 1-particle theory may be removed by expanding the latter equation in powers of {tau}:=q{sup 2}/6{pi}m. The radiation-induced change in entropy is explored and its physical origin is discussed. As a simple demonstration of the theory, the radiative damping rate of longitudinal plasma waves is calculated.

Noble, A.; Jaroszynski, D. A. [SUPA and University of Strathclyde, Glasgow G4 0NG (United Kingdom); Burton, D. A.; Gratus, J. [Department of Physics, Lancaster University, Lancaster LA1 4YB, United Kingdom and The Cockcroft Institute of Accelerator Science and Technology, Daresbury Science and Innovation Campus, Daresbury, Warrington WA4 4AD (United Kingdom)

2013-04-15

378

Modeling Clinical Radiation Responses in the IMRT Era  

Science.gov (United States)

The purpose of this review is to highlight the critical issues of radiobiological models, particularly as they apply to clinical radiation therapy. Developing models of radiation responses has a long history that continues to the present time. Many different models have been proposed, but in the field of radiation oncology, the linear-quadratic (LQ) model has had the most impact on the design of treatment protocols. Questions have been raised as to the value of the LQ model given that the biological assumption underlying it has been challenged by molecular analyses of cell and tissue responses to radiation. There are also questions as to use of the LQ model for hypofractionation, especially for high dose treatments using a single fraction. While the LQ model might over-estimate the effects of large radiation dose fractions, there is insufficient information to fully justify the adoption of alternative models. However, there is increasing evidence in the literature that non-targeted and other indirect effects of radiation sometimes produce substantial deviations from LQ-like dose-response curves. As preclinical and clinical hypofractionation studies accumulate, new or refined dose-response models that incorporate high-dose/fraction non-targeted and indirect effects may be required, but for now the LQ model remains a simple, useful tool to guide the design of treatment protocols.

Schwartz, J. L.; Murray, D.; Stewart, R. D.; Phillips, M. H.

2014-03-01

379

Modeling of Space Radiation Exposure Estimation Program for Pilots, Crew and Passengers on Commercial Flights  

Science.gov (United States)

There has been a rapid increase of the concern on the space radiation effect on pilots, crew and passengers at the commercial aircraft altitude (~ 10 km) recently. It is because domestic airline companies, Korean Air and Asiana Airlines have just begun operating the polar routes over the North Pole since 2006 and 2009 respectively. CARI-6 and CARI-6M are commonly used space radiation estimation programs which are provided officially by the U.S. federal aviation administration (FAA). In this paper, the route doses and the annual radiation doses for Korean pilots and cabin crew were estimated by using CARI-6M based on 2012 flight records. Also the modeling concept was developed for our own space radiation estimation program which is composed of GEANT4 and NRLMSIS00 models. The GEANT4 model is used to trace the incident particle transports in the atmosphere and the NRLMSIS00 model is used to get the background atmospheric densities of various neutral atoms at the aircraft altitude. Also presented are the results of simple integration tests of those models and the plan to include the space weather variations through the solar proton event (SPE) prediction model such as UMASEP and the galactic cosmic ray (GCR) prediction model such as Badhwar-O¡¯Neill 2010.

Hwang, Junga; Dokgo, Kyunghwan; Choi, Enjin; Park, Jong-Sun; Kim, Kyung-Chan; Kim, Hang-Pyo

2014-03-01

380

G temperature dependencies and the spur diffusion model of radiation chemistry  

International Nuclear Information System (INIS)

The effect of temperature (700F to 3500F) on the radiation-induced chemical change in acidic aqueous solutions was studied. Air saturated Fricke, deaerated Fricke, and air saturated ceric-cerous dosimeters were the solutions studied. The purposes of the study were to (1) develop experimental techniques necessary to give accurate, reproducible G(P) values, and (2) measure the effect of temperature on the primary radical and molecular yields. The primary molecular yields, G/sub H2/ and G/sub H2O2/ both increased with temperature. The value for G/sub OH/ was independent of temperature, and G/sub H/ decreased with temperature increases. The observed values were consistent with the spur diffusion model of radiation chemistry if the initial electron spur radius decreases with increasing temperature, with all other parameters constant. (DP)