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Sample records for air kerma index

  1. Evaluation of entrance surface air kerma from exposure index in computed radiography

    International Nuclear Information System (INIS)

    The aim of this study was to establish an indirect method to calculate the values of entrance surface air kerma in patients undergoing diagnostic examinations in X-ray systems with computed radiography based on the exposure index. The entrance surface air kerma values were compared with values obtained also indirectly based on measurements of X-ray tube output. The mean±standard deviation (1?) and third quartile for entrance surface air kerma calculated from the exposure index were 2.1±1.0 mGy and 3.0 mGy, respectively. For entrance surface air kerma based on measurements of the X-ray tube output, the mean±standard deviation (1?) and third quartile were respectively 3.1±1.9 mGy and 5.5 mGy. The observed values of entrance surface air kerma are smaller than the reference level adopted in Brazil (10 mGy). The results obtained with both methods were similar when taking into account the estimated uncertainties in the determination of air kerma values, although the reproducibility of the determinations based on the exposure index is better. - Highlights: • Indirect method to calculate entrance surface air kerma in computed radiography. • Method based on the exposure index for digital radiography. • Comparison with an indirect method based on measurements of X-ray tube output

  2. Image quality and volume computed tomography air kerma index (Cvol) evaluation in Recife

    International Nuclear Information System (INIS)

    The Computed Tomography (CT) is an important diagnostic imaging method, widely used. However, in spite of all the advantages and technologic advances within the CT scanners, the tomographic procedures result in high absorbed doses to patients. The main objective of this work was to perform a dosimetric study of CT scanners located at Recife and to evaluate the image quality on CT examinations in these equipment. The volume CT air kerma index (CVOL) and air kerma length product (PKL,CT) were estimated. These values were calculated using normalized weighted air kerma indexes in CT standard dosimetry phantoms (nCW), supplied by ImPACT group for several CT scanners, and the scan parameters of routine head, routine chest and hi-resolution chest CT exams performed at 20 institutions. The irradiation parameters of 15 adult patients for each CT procedure were registered at six participating centres, at which the phantom from the American College of Radiology (ACR) CT accreditation protocol was used for the image quality measurements. For routine head exams, the CVOL values varied between 12 and 58 mGy (at the posterior fossa) and 15 to 58 mGy (at the cerebrum) and the PKL,CT, from 150 to 750 mGy·cm. The CVOL values for routine chest procedures varied from 3 to 26 mGy and the PKL,CT, between 120 and 460 mGy·cm. In relation to Hi-resolution chest exams, CVOL values were from 1.0 to 2.7 mGy and the PKL,CT values varied between 24 and 67 mGy·cm. The image quality evaluations results showed that almost all scanners presented at least one inadequacy. One of the equipment presented faults at 70% of the tests. With regard to the image noise, only two scanners presented acceptable results. From these results, it is possible to conclude that the volume CT air kerma index values are lower than the European reference levels. However, the image quality of these CT scanners does not attend the ACR requirements, suggesting the need to implement quality assurance programs at the evaluated institutions. (author)

  3. Image quality and volume computed tomography air kerma index (C{sub vol}) evaluation in Recife; Avaliacao da qualidade de imagem e do indice volumetrico de Kerma ar em tomografia computadorizada (C{sub vol}) em Recife

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Marcos Ely Almeida

    2008-07-01

    The Computed Tomography (CT) is an important diagnostic imaging method, widely used. However, in spite of all the advantages and technologic advances within the CT scanners, the tomographic procedures result in high absorbed doses to patients. The main objective of this work was to perform a dosimetric study of CT scanners located at Recife and to evaluate the image quality on CT examinations in these equipment. The volume CT air kerma index (C{sub VOL}) and air kerma length product (P{sub KL,CT}) were estimated. These values were calculated using normalized weighted air kerma indexes in CT standard dosimetry phantoms ({sub n}C{sub W}), supplied by ImPACT group for several CT scanners, and the scan parameters of routine head, routine chest and hi-resolution chest CT exams performed at 20 institutions. The irradiation parameters of 15 adult patients for each CT procedure were registered at six participating centres, at which the phantom from the American College of Radiology (ACR) CT accreditation protocol was used for the image quality measurements. For routine head exams, the C{sub VOL} values varied between 12 and 58 mGy (at the posterior fossa) and 15 to 58 mGy (at the cerebrum) and the P{sub KL,CT}, from 150 to 750 mGy{center_dot}cm. The C{sub VOL} values for routine chest procedures varied from 3 to 26 mGy and the P{sub KL,CT}, between 120 and 460 mGy{center_dot}cm. In relation to Hi-resolution chest exams, C{sub VOL} values were from 1.0 to 2.7 mGy and the P{sub KL,CT} values varied between 24 and 67 mGy{center_dot}cm. The image quality evaluations results showed that almost all scanners presented at least one inadequacy. One of the equipment presented faults at 70% of the tests. With regard to the image noise, only two scanners presented acceptable results. From these results, it is possible to conclude that the volume CT air kerma index values are lower than the European reference levels. However, the image quality of these CT scanners does not attend the ACR requirements, suggesting the need to implement quality assurance programs at the evaluated institutions. (author)

  4. Recent developments and current status of air kerma standards

    International Nuclear Information System (INIS)

    Primary Standard Dosimetry Laboratories (PSDL) usually maintain air kerma standards for kilovoltage x-rays (10 kV to 300 kV) and for 137Cs- and 60Co-? radiation. Free-air ionisation chambers (FAC) and cavity ionisation chambers are used as primary air kerma standards for kilovoltage x-rays and for 137Cs- and 60Co-? radiation, respectively. The majority of the National Metrology Institutes (NMIs) signed the Mutual Recognition Arrangement (MRA) of national measurement standards and of calibration and measurement certificates issued by NMIs. The MRA has been available for signature since 14th October 1999. According to the MRA, the signatories participate in CIPM key comparisons executed by the Consultative Committees or the BIPM, leading to a key comparison reference value. The degree of equivalence of a national measurement standard is expressed quantitatively in terms of its deviation from the key comparison reference value and the uncertainty of this deviation. For air kerma standards the Consultative Committee for Ionising Radiation (CCRI(I)) currently maintains three types of key comparisons and a so-called supplementary comparison. The air kerma key comparisons are organised bilaterally and are carried out between the air kerma standards of the BIPM and the participating NMIs. The radiations used are low-energy (10 kV to 50 kV) and medium energy (100 kV to 250 kV) x-ray beams and 137Cs- and 60Co-? radiation. To be entitled to enter the key comparison database with respect to air kerma an NMI has to participate in a key comparison within a time period of 10 years. In keeping with the longstanding method of presenting the data, the CCRI(I) took the decision at its meeting in 1999 to use the BIPM determination of air kerma rate as the key comparison reference value. For this reason the BIPM air kerma standards are of special importance. Due to the fact that the air kerma key comparisons have been conducted on an ongoing basis since 1966 for low-energy x-rays and since 1975 for medium-energy x-rays and 60Co-? radiation the results represent an invaluable database which can be regarded as an indicator of the status of the air kerma standards operated worldwide. Consequently, this database and the reports of the NMIs to the CCRI(I) meetings which take place periodically every two years were used for the current status report as an essential source of information. Because different techniques are used to measure the air kerma rate of kilovoltage x-rays and 137Cs- and 60Co-? radiation this status report is divided in this two parts. Undoubtedly, the most important new development was the re-evaluation of several correction factors required for cavity ionization chamber standards. However, there were also interesting developments using Monte Carlo techniques and spectrometry for the determination of x-ray quality dependent correction factors of FACs

  5. Kerma determination in air on mamma by thermoluminescence; Determinacion de Kerma en aire en mama por termoluminiscencia

    Energy Technology Data Exchange (ETDEWEB)

    Palacios P, L. L.; Rivera M, T. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Av. Legaria 694, 11500 Mexico D. F. (Mexico)], e-mail: lpalaciop@ipn.mx

    2009-10-15

    In this work the experimental results of the entrance exposition are shown and Kerma in air [mGy] in mamma obtained by irradiation of accreditation phantom of American College of Radiology (ACR). The irradiations were realized in a conventional mammography equipment of Hospital Juarez in Mexico; the technique used during the irradiations was of automatic exposition; the thickness for the phantom ACR obtained by the technique were of 4.2 and 4.5 cm; the kilo voltage pick was of 24 kV{sub p}, the time and the milli amperage per second variable. The measuring of Kerma in air was obtained with thermoluminescent dosemeters of solid state, of nano particles of zirconium dioxide prepared by the precipitation method. The dosemeters were homogenized previously in low energies of X-rays that are those used for mammography. The thermoluminescent dosemeters of ZrO{sub 2} were calibrated by means of an ionization chamber for different expositions. The calibration curve is reported for the exposition and Kerma in air against thermoluminescent intensity obtained by reading of thermoluminescent dosemeters of ZrO{sub 2}, as well as the technique employee for the Kerma determination in air and entrance exposition in mamma. (Author)

  6. Recent developments and current status of air kerma standards

    International Nuclear Information System (INIS)

    The current status of air kerma standards for kilovoltage X rays and for 137Cs and 60Co gamma radiation maintained at primary standards dosimetry laboratories is reviewed using results of the bilateral key comparisons between the air kerma standards of the Bureau international des poids et mesures (BIPM) and those of national metrology institutes. Owing to the re-evaluation of kwall and kan, which are the correction factors for wall effects and axial beam non-uniformity for cavity ionization chambers, respectively, a significant increase of about 0.8% in the realization of the gray for air kerma in both 137Cs and 60Co fields is to be expected. A consistent set of free air chamber correction factors for electron loss, photon scatter, fluorescence and bremsstrahlung was calculated at the BIPM using state of the art Monte Carlo methods for all free air chamber standards in use worldwide. Consistent use of this set by all national metrology institutes would further improve the degree of equivalence of free air chamber standards. (author)

  7. Evaluation of entrance surface air kerma in pediatric chest radiography

    International Nuclear Information System (INIS)

    The objective of this study was to evaluate the entrance surface air kerma in pediatric chest radiography. An evaluation of 301 radiographical examinations in anterior–posterior (AP) and posterior–anterior (PA) (166 examinations) and lateral (LAT) (135 examinations) projections was performed. The analyses were performed on patients grouped by age; the groups included ages 0–1 y, 1–5 y, 5–10 y, and 10–15 y. The entrance surface air kerma was determined with DoseCal software (Radiological Protection Center of Saint George's Hospital, London) and thermoluminescent dosimeters. Two different exposure techniques were compared. The doses received by patients who had undergone LAT examinations were 40% higher, on average, those in AP/PA examinations because of the difference in tube voltage. A large high-dose “tail” was observed for children up to 5 y old. An increase in tube potential and corresponding decrease in current lead to a significant dose reduction. The difference between the average dose values for different age ranges was not practically observed, implying that the exposure techniques are still not optimal. Exposure doses received using the higher tube voltage and lower current-time product correspond to the international diagnostic reference levels. - Highlights: • The entrance surface air kerma of chest X-ray examinations in pediatric patients was estimated. • The data were analyzed for patients aged up to 15 y, stratified by age. • The doses of LAT examinations were 40% higher than of AP/PA because of kV used. • An increase in kV with a decrease in mAs leads to significant dose reduction

  8. Air kerma rates measurement in an interventional cardiology suite

    International Nuclear Information System (INIS)

    In Interventional Cardiology (IC), the assessment of the radiation that the physicians are exposed to is extremely important because the irradiation is not uniform and the received doses are substantially high. During the procedure, the radiation control is complex and there are several reasons for the high exposure levels. It is necessary to perform dosimetric assessments in different parts of the physicians' body and in different specific points of the examination room. By analyzing this information it is possible to determine the probable causes and to provide recommendations, aiming at optimizing the radiological protection. This work had the following objectives: to assess the exposition levels at representative points of critical anatomical regions of the physicians' body who perform IC examinations; to provide means to implement personal monitoring procedures; and to make them aware of the radiation risks. Measurements of air kerma rates were performed in 45 points around the examination table, along the room. Such measurements were made in the conditions frequently used in coronary angiography and coronary angioplasties procedures: adult patient phantom; RAO, LAO and AP incidences; fluoro and digital modes; 13cm and 17cm magnification modes; frequencies of 30f/s (fluoro) and 15 f/s (digital); typical field size used during examinations. Data were obtained at the lenses, chest, hands, gonads and knees levels. For AP incidence, the lowest contributions for scattered radiation and a more homogeneous distribution of radiation were observed. The highest air kerma rates were obtained during digital acquisition mode and for LAO incidence on interventional radiologists, anaesthesists and nurses. The most critical anatomical regions were the knees and gonads. Air kerma rates of about 7,8mGy/h were registered in some places. At physicians' hands position, rates of about 5mGy/h were reached. In several points and levels measured (workload ? 6 examinations/day), this air kerma rates would produce a higher dose than the annual limits. This work shows the need to implement additional protection devices; to elaborate safety guidelines; to train staff on radiological protection, and to implement the use of additional dosemeters attached to critical points. (author)

  9. Routine measurement of gamma ray air kerma rate in the environment

    International Nuclear Information System (INIS)

    This Note, issued by Her Majesty's Inspectorate of Pollution, provides technical guidance on the routine measurement of gamma ray air kerma rate in the environment. It includes a protocol for the measurement, interpretation and reporting of environmental gamma ray air kerma rates and appendices reviewing existing techniques, instruments, calibration facilities and the physics of such measurements. (UK)

  10. Comparison of the NIST and ENEA air kerma standards

    International Nuclear Information System (INIS)

    A comparison was made between the National Institute of Standards and Technology (NIST) and Ente per le Nuov Tecnologie l'Energia e l'Ambiente (ENEA) air kerma standards for medium energy x rays and 60Co gamma rays. The comparison took place at ENEA in June 1994. Two different transfer chambers from NIST were used for the comparison. The measurements were made at radiation qualities similar to those used at the Bureau International des Poids et Mesures (BIPM) (generating voltages of 100 kV, 135 kV, 180 kV and 250 kV, respectively) and with 60Co gamma radiation. The transfer chamber calibration factors obtained at the NIST and at the ENEA agreed with one another to 0.03% for 60Co gamma radiation and between 0.1% to 0.8% for the medium energy x-ray beam codes

  11. X-rays spectrum and air Kerma during a mammography study; Espectro de los rayos X y Kerma en aire durante un estudio mamografico

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez G, J. [Instituto Nacional de Estadistica Geografia e Informatica, Av. Heroes de Nacozari Sur 2301, Fracc. Jardines del Parque, 20276 Aguascalientes (Mexico); Hernandez V, R.; Hernandez D, V. M.; Vega C, H. R. [Unidad Academica de Estudios Nucleares, Universidad Autonoma de Zacatecas, Cipres 10, Fracc. La Penuela, 98068 Zacatecas (Mexico)], e-mail: fermineutron@yahoo.com

    2009-10-15

    In this calculation series was modeled the source of electrons, the target and the filter. Using thermoluminescent dosemeters of ZrO{sub 2}+PTFE the air Kerma was measured in five points located on a phantom made with acrylic and water when it was exposed to a X-rays beam produced by electrons of 24 KeV and 10 m A of current that produces a mammography. The air Kerma values at the entrance surface of the phantom were compared with values calculated by Monte Carlo methods. The air Kerma values measured indicate that approximately the five points receive the same air Kerma, what means that the beam is homogeneous, of the Monte Carlo calculations we find that the center receives a greater dose what implies that the beam is not uniform, the explanation of this fact is attributed to was used a simple model in the calculations, nevertheless, the air Kerma average measured at the entrance surface of the phantom was of 0.96 +{sub -} 0.03 m G, while the other obtained by the calculations was of 0.96 +{sub -} 0.06 mGy, to compare both do not exist significant differences. (author)

  12. Evaluation and test of 192Ir air kerma strength for afterloading systems

    International Nuclear Information System (INIS)

    Objective: To study the method of measuring air kerma strength of afterloading units with 192Ir source by using well type ionization chamber. Methods: The air kerma strength of 30 afterloading units with 192Ir source was measured using 2000A electrometer and 1000 plus well type ionization chamber, and apparent activity of the source was calculated with the air kerma strength and apparent activity conversion factor. The measured activity of the source was compared with the original value of the source provided by the manufacturer, and the relevant deviation should be within ±5%. Results: The air kerma strength of afterloading units with 192Ir sources was tested. The relevant deviation of the measured activity and the original value was within -0.1%-4.4%. Conclusions: The measurement method with a well type ionization chamber is convenient and highly accurate which can be used for the test of quality control in hospitals. (authors)

  13. X-rays spectrum and air Kerma during a mammography study

    International Nuclear Information System (INIS)

    In this calculation series was modeled the source of electrons, the target and the filter. Using thermoluminescent dosemeters of ZrO2+PTFE the air Kerma was measured in five points located on a phantom made with acrylic and water when it was exposed to a X-rays beam produced by electrons of 24 KeV and 10 m A of current that produces a mammography. The air Kerma values at the entrance surface of the phantom were compared with values calculated by Monte Carlo methods. The air Kerma values measured indicate that approximately the five points receive the same air Kerma, what means that the beam is homogeneous, of the Monte Carlo calculations we find that the center receives a greater dose what implies that the beam is not uniform, the explanation of this fact is attributed to was used a simple model in the calculations, nevertheless, the air Kerma average measured at the entrance surface of the phantom was of 0.96 +- 0.03 m G, while the other obtained by the calculations was of 0.96 +- 0.06 mGy, to compare both do not exist significant differences. (author)

  14. Attenuation effects on the kerma rates in air after cesium depositions on grasslands

    International Nuclear Information System (INIS)

    Since the reactor accident of Chernobyl, cesium depth profiles and nuclide-specific kerma rates in air have been determined for various grassland sites in south Bavaria and in Ukraine. The sites are described by soil characteristics, annual precipitation, distance from release point, mode of deposition, and activity per unit area. The effects of surface roughness and migration of cesium into the soil on the kerma rate in air over grasslands was determined by two methods. The kerma rates in air obtained by the evaluations of in situ gamma-ray spectrometry results and of measured activity distributions in the soil showed only negligible differences for the observation period of 6 years after deposition. for the sites in Ukraine the kerma rate in air per activity per unit area was found to be systematically 40% higher than in Bavaria. The results from Bavaria on the attenuation of the kerma rate and a data set, including experiences from the weapons test fallout, are analytically approximated as a function of time up to 25 years after deposition. (orig.)

  15. Evaluation of the air kerma rates stability used in diagnostic radiology calibration

    International Nuclear Information System (INIS)

    The objective of this work was to perform tests in order to evaluate the stability of the air kerma rates measured with the dosimetric reference system of the calibration laboratory of IPEN (LCI)). The diagnostic radiology reference system consists of a parallel plates ionization chamber with volume of 1cm3, PTW, model 77334, connected to a PTW electrometer, model UNIDOS, type 10001, and it is used a 14C as check source. This parallel plate ionization chamber can be also used for radiography and fluoroscopy modes measurements during the characterization of the diagnostic radiology beams. The air kerma rates obtained during the calibration measurements were are evaluated from 2005 to 2007. (author)

  16. X-Rays spectrum and air kerma during a mammography study;Espectro de los rayos X y kerma en aire durante un estudio mamografico

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez G, J. [Instituto Nacional de Estadistica Geografia e Informatica, Direccion General de Innovacion y Tecnologia de Informacion, Av. Heroes de Nacozari Sur No. 2301, Fracc. Jardines del Parque, 20276 Aguascalientes (Mexico); Hernandez V, R.; Chacon R, A.; Vega C, H. R., E-mail: ramirezgonzalezjaime@yahoo.com.m [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico)

    2009-10-15

    The X-rays spectrum produced in a mammography has been calculated by means of Monte Carlo methods. In this calculation series it is modeled the electrons source, the target and the filter. The spectra were calculated for an energy of the electrons of 28 keV and for targets of W, Mo and Rh. The calculations extended to analyze the effect that produces the filters inclusion in the spectra; the spectra of W-A1, Rh-Rh, Mo-Mo, Mo-Rh and Mo-Be were calculated this way. Using thermoluminescent dosemeters of ZrO{sub 2}+PTFE the air kerma was measured in five points located on a phantom made with acrylic and water when it is was exposed to a X-rays beam produced by electrons of 24 keV and 10 m A of current that it produces a mammography. The values of the air kerma on the entrance surface of the phantom were compared with the calculated values by means of Monte Carlo methods. The calculated spectra present a continuous component and another discreet and its form is similar to the reported spectra in the literature. The filters inclusion allows the elimination of the low energy photons that do not have utility in the obtaining of the mammography image and only they contribute to deposit a dose in the mamma. The values of the measured air kerma indicate that the five points receive the same air kerma approximately, what means that the beam is homogeneous, of the Monte Carlo calculations we find that the center receives a bigger dose which implies that the beam is not uniform, the explanation on this fact it is attributed to that a simple model was used in the calculations, nevertheless, the average of the air kerma measured on the entrance surface of the phantom was of 0.96 +- 0.03 m G, while the obtained by means of the calculations was of 0.96 +- 0.06 mGy, when comparing both significant differences do not exist. (Author)

  17. Seasonal variation of air kerma in the 'Vulcano Porto' area (Aeolian Islands, Italy)

    International Nuclear Information System (INIS)

    Air kerma was measured in the 'Vulcano Porto' area of the Vulcano Island, belonging to the Aeolian Islands, in the Mediterranean Sea. Measurements were carried out using thermoluminescence dosimeters. The relationship between observed dose values and source lithology has been assessed. Data show a seasonal variation due to weather conditions but also probably related to features of the soils, making the variation more evident

  18. Air kerma rate constants for gamma emitters used most often in practice

    International Nuclear Information System (INIS)

    It is often required to estimate the dose rate at a distance from radionuclides that are sources of X rays and gamma rays. Such calculations may be required for planning radiation protection measures in the vicinity of radioactive sources or patients containing radionuclides, calibrations of radiation instruments or for estimating the absorbed dose rate to patients receiving brachytherapy. The factor relating activity and air kerma rate is called air kerma rate constant - ?o-bar. In this paper, the results of recalculation of this quantity for unfiltered point sources of radionuclides in practice used most often are given. The calculations included corrections for internal conversion of X rays and gamma rays and detailed accounting of the generation of the K and L series X rays from internal conversion and electron capture. Particular air kerma rate constants were calculated for each discrete line in the photon spectrum of radionuclide with a yield per decay event >0.01% and the energy >20 keV. Since the energy structure of the photon spectra and accessible discrete numerical values of the mass energy-transfer coefficient for air are not the same, the cubic spline interpolation was used to obtained the coefficient, where the photon spectrum data are available. In the calculation, the latest gamma ray spectral data for all radionuclides and latest data for the mass energy-transfer coefficient for air are used. Air kerma rate constants for the following 35 radionuclides are calculated: 11C, 13N, 15O, 18F, 24Na, 42K, 43K, 51Cr, 52Fe, 59Fe, 57Co, 58Co, 60Co, 67Ga, 68Ga, 75Se, 99Mo, 99mTc, 111In, 113mIn, 123I, 125I, 131I, 127Xe, 133Xe, 137Cs, 152Eu, 154Eu, 170Tm, 182Ta, 192Ir, 197Hg, 198Au, 201Tl and 241Am. (authors)

  19. Evaluating air kerma at a medical cyclotron after refined shielding design using the TLD approach

    International Nuclear Information System (INIS)

    Cyclotrons are increasingly constructed at medical universities in Taiwan to produce nuclear medicine. However, their operation generates amounts of highly energetic photons from 18O(p, ?n)18F reactions. This reaction posed a health hazard to the public. Chung Shan University Hospital had to increase its 2-deoxy-2-[18F]-fluoro-D-glucose products in 2011 to 11.5 times that in 2004 and redesign the self-shielded (CTI) Radioisotope Delivery System (RDS)-111 to meet guild requirements regarding the production of positron emission tomography (PET). This study is the first to evaluate air kerma in a CTI RDS-111 cyclotron center with a thermoluminescent dosimeter (TLD). Air kerma of up to 17.0±2.8 mGy/mo indicated that heavy leakage of photons penetrated the PET/CT facility. The new L-shaped concrete shield and added d2 door can adequately protect the public. The minimum detectable limit of air kerma is discussed to demonstrate the reliability of the TLD approach. (author)

  20. X-Rays spectrum and air kerma during a mammography study

    International Nuclear Information System (INIS)

    The X-rays spectrum produced in a mammography has been calculated by means of Monte Carlo methods. In this calculation series it is modeled the electrons source, the target and the filter. The spectra were calculated for an energy of the electrons of 28 keV and for targets of W, Mo and Rh. The calculations extended to analyze the effect that produces the filters inclusion in the spectra; the spectra of W-A1, Rh-Rh, Mo-Mo, Mo-Rh and Mo-Be were calculated this way. Using thermoluminescent dosemeters of ZrO2+PTFE the air kerma was measured in five points located on a phantom made with acrylic and water when it is was exposed to a X-rays beam produced by electrons of 24 keV and 10 m A of current that it produces a mammography. The values of the air kerma on the entrance surface of the phantom were compared with the calculated values by means of Monte Carlo methods. The calculated spectra present a continuous component and another discreet and its form is similar to the reported spectra in the literature. The filters inclusion allows the elimination of the low energy photons that do not have utility in the obtaining of the mammography image and only they contribute to deposit a dose in the mamma. The values of the measured air kerma indicate that the five points receive the same air kerma approximately, what means that the beam is homogeneous, of the Monte Carlo calculations we find that the center receives a bigger dose which implies that the beam is not uniform, the explanation on this fact it is attributed to that a simple model was used in the calculations, nevertheless, the average of the air kerma measured on the entrance surface of the phantom was of 0.96 ± 0.03 m G, while the obtained by means of the calculations was of 0.96 ± 0.06 mGy, when comparing both significant differences do not exist. (Author)

  1. Calculated neutron air kerma strength conversion factors for a generically encapsulated Cf-252 brachytherapy source

    CERN Document Server

    Rivard, M J; D'Errico, F; Tsai, J S; Ulin, K; Engler, M J

    2002-01-01

    The sup 2 sup 5 sup 2 Cf neutron air kerma strength conversion factor (S sub K sub N /m sub C sub f) is a parameter needed to convert the radionuclide mass (mu g) provided by Oak Ridge National Laboratory into neutron air kerma strength required by modern clinical brachytherapy dosimetry formalisms indicated by Task Group No. 43 of the American Association of Physicists in Medicine (AAPM). The impact of currently used or proposed encapsulating materials for sup 2 sup 5 sup 2 Cf brachytherapy sources (Pt/Ir-10%, 316L stainless steel, nitinol, and Zircaloy-2) on S sub K sub N /m sub C sub f was calculated and results were fit to linear equations. Only for substantial encapsulation thicknesses, did S sub K sub N /m sub C sub f decrease, while the impact of source encapsulation composition is increasingly negligible as Z increases. These findings are explained on the basis of the non-relativistic kinematics governing the majority of sup 2 sup 5 sup 2 Cf neutron interactions. Neutron kerma and energy spectra resul...

  2. Diaphragm correction factors for free-air chamber standards for air kerma in x-rays

    International Nuclear Information System (INIS)

    At present, only a correction factor for photon transmission, kl, is systematically applied for the entrance diaphragm of free-air chamber standards for air kerma. In the present work, the Monte Carlo code PENELOPE is used to re-evaluate kl for the BIPM standards and new correction factors are calculated for photon scatter and for fluorescence production in the diaphragm. An additional effect arising from electrons emitted from the diaphragm is shown to be significant at the highest photon energies. The results for the radiation qualities used for international comparisons give a combined diaphragm correction factor kdia = 0.9980(3) for the BIPM medium-energy standard at 250 kV. This is significantly different from the factor kl = 0.9996(1) in use at present and it might be concluded that differences are likely to exist for all free-air chamber standards. The effect of using a conical taper at the downstream edge of the diaphragm is shown to be negligible for these radiation qualities.

  3. Effects of aluminum-copper alloy filtration on photon spectra, air kerma rate and image contrast

    Scientific Electronic Library Online (English)

    Andréa, Gonçalves; João Manuel Domingos de Almeida, Rollo; Marcelo, Gonçalves; Francisco, Haiter Neto; Frab Norberto, Bóscolo.

    2004-12-01

    Full Text Available Este estudo avaliou a redução da taxa de kerma no ar, o espectro de energia dos raios X e alterações na qualidade da imagem radiográfica. Comparações com várias espessuras do filtro de liga de alumínio-cobre em três diferentes porcentagens foram feitas com o filtro de alumínio. Os experimentos foram [...] feitos utilizando-se um aparelho de raios X odontológico convencional, obtendo radiografias com auxílio de um fantoma de segmento de mandíbula e de uma escala de densidade confeccionada com alumínio laminado. Dependendo da espessura da filtração da liga de alumínio-cobre, o feixe de raios X pôde ser endurecido em relação ao filtro de alumínio. O uso do filtro de liga de alumínio-cobre resultou em 8,40% a 47,33% de redução da taxa média de kerma no ar e indicou contraste da imagem radiográfica sem alteração, quando comparado com a filtração de alumínio, mostrando que os filtros de liga de alumínio-cobre tornam-se alternativas aceitáveis em relação aos filtros de alumínio. Abstract in english This study evaluated the performance of aluminum-copper alloy filtration, without the original aluminum filter, for dental radiography in terms of x-ray energy spectrum, air kerma rate and image quality. Comparisons of various thicknesses of aluminum-copper alloy in three different percentages were [...] made with aluminum filtration. Tests were conducted on an intra-oral dental x-ray machine and were made on mandible phantom and on step-wedge. Depending on the thickness of aluminum-copper alloy filtration, the beam could be hardened and filtrated. The use of the aluminum-copper alloy filter resulted in reductions in air kerma rate from 8.40% to 47.33%, and indicated the same image contrast when compared to aluminum filtration. Aluminum-copper alloy filtration may be considered a good alternative to aluminum filtration.

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

    International Nuclear Information System (INIS)

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

  5. Preliminary study on quality audit for air kerma strength determination of high dose rate brachytherapy sources

    International Nuclear Information System (INIS)

    Brachytherapy is one of the modes of treatment of cancerous cells. High dose rate (HDR) brachytherapy using high activity 192Ir source has become very popular for all brachytherapy applications worldwide. The accurate dose delivery to the patient depends on many dosimetric parameters. Air Kerma Strength is one of the clinical parameters which is recommended by many international bodies to specify the brachytherapy source strength and used in the TG-43 dosimetry formalism. Our study concludes that TLD based Quality Audit method can be used for postal audit of HDR brachytherapy sources strength verification

  6. Product kerma in the air-area and radiation dose in dental radiodiagnosis

    International Nuclear Information System (INIS)

    The main purpose of patient dosimetry in diagnostic radiology is to determine dosimetric quantities for the establishment and use of reference levels and comparative risk assessment. In recent publications the use of the air kerma-area product, PKA, has been suggested in dental radiology, as this quantity is more closely related to risk. The aim of this study was to perform a preliminary survey of PKA and effective dose in different types of dental examinations. The future perspective is a large-scale survey for the establishment and use of diagnostic reference levels in dentistry in Brazil. (author)

  7. Proposed specification for a primary standard of air kerma for 60Co, 137Cs and 192Ir ?-ray sources

    International Nuclear Information System (INIS)

    The three cavity chambers, the mean response of which constitutes the primary standard of air kerma for 60Co and 137Cs ?-rays in the United Kingdom, have been in continuous, almost daily, use at the National Physical Laboratory (NPL) since 1956. These chambers were initially designed for use with 2 MV X-rays at therapy level air kerma rates. However since 1978 they have also been used for protection level air kerma rates, initially, with X-rays generated at 1 MV and 2 MV and more recently with 60Co and 137Cs ?-rays. They have been used for therapy level air kerma calibrations with 60Co ?-rays since 1997 following the demise of the NPL 2 MV Van de Graaff generator. This report describes the proposals for a new primary standard and the methods that will be used to give a better performance than the present standard when used with air kerma rates from as high as 1 Gy min-1 down to 10 mGy hr-1. The design will also seek to ensure that the standard will be capable of providing traceable calibration for 192Ir high dose rate brachytherapy sources. (author)

  8. Air kerma and absorbed dose on the torso of a patient during a mammography study;Kerma en aire y dosis absorbida en el torso de una paciente durante un estudio mastografico

    Energy Technology Data Exchange (ETDEWEB)

    Hernadez O, M.; Duran M, H. A.; Pinedo S, A.; Gonzalez G, R.; Guerra M, J. A.; Salas L, M. A.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Rivera M, T. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Av. Legaria 694, 11500 Mexico D. F. (Mexico); Azorin N, J., E-mail: mar_h2o@hotmail.co [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Av. San Rafael Atlixco 186, 09340 Mexico D. F. (Mexico)

    2009-10-15

    Two dosimetric magnitudes, due to the dispersed radiation, have been determined during a mammography study. The magnitudes that were determined are the kerma at the entrance of the torso and the absorbed dose by the torso. This determination was made in a paraffin phantom and with thermoluminescent dosemeters. One of the important parameters in the radiological protection of a patient to which is practiced a mammography is the value of the media glandular dose. However, during the taking of the X-ray a radiation portion that impacts on the mammary gland it is dispersed toward the patient's torso. In this work thermoluminescent dosemeters of ZrO{sub 2} has been used to determine the kerma at the entrance of the torso like the absorbed dose. The dosemeters was placed on the surface of the torso phantom while to the mamma phantom was made the mammography. As mamma phantom was used glucose serum to 5%. Of the obtained results we find that 3% of the air kerma at the entrance of the mamma it corresponds at the air kerma that receives the torso and 3.2% of the media glandular dose it is the absorbed dose of the same one. Another important result is the percentage value of the air kerma on the entrance of the thyroid area during a mammography, due to the dispersed radiation, it is 4% of the kerma at the entrance of the mamma. The air kerma at the entrance of the thyroid is of 0.41 +-0.07 mGy, 10% of this value corresponds to the absorbed dose by the thyroid. Therefore, it is observed that the media glandular dose and the air kerma at the entrance of the mamma they influence on the dispersed radiation toward the torso. Also, the superior part of the torso has less attenuation capacity to the dispersed radiation that those located in the inferior part. Therefore, the thyroid receives the major quantity of air kerma at the entrance. (Author)

  9. Product kerma in the air-area and radiation dose in dental radiodiagnosis; Produto kerma ar-area e dose efetiva em radiodiagnostico odontologico

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Alessandro Martins da, E-mail: amcosta@usp.br [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Filosofia, Ciencias e Letras. Dept. de Fisica

    2014-07-01

    The main purpose of patient dosimetry in diagnostic radiology is to determine dosimetric quantities for the establishment and use of reference levels and comparative risk assessment. In recent publications the use of the air kerma-area product, PKA, has been suggested in dental radiology, as this quantity is more closely related to risk. The aim of this study was to perform a preliminary survey of PKA and effective dose in different types of dental examinations. The future perspective is a large-scale survey for the establishment and use of diagnostic reference levels in dentistry in Brazil. (author)

  10. Avaliação do kerma no ar na superfície de entrada e da qualidade da imagem em radiografias de tórax / Evaluation of entrance surface air kerma rate and clinical images quality in chest radiography

    Scientific Electronic Library Online (English)

    Angelo Bernardo Brasil de, Souza; Simone Kodlulovich, Dias; Fernando Mecca, Augusto; Winston Andrade, Marques.

    2009-10-01

    Full Text Available OBJETIVO: Avaliar os fatores de técnica utilizados durante exames de tórax póstero-anterior em pacientes-padrão e correlacioná-los aos valores de kerma no ar na superfície de entrada e à qualidade das imagens clínicas. MATERIAIS E MÉTODOS: O estudo foi realizado em três hospitais do Rio de Janeiro, [...] num total de cinco salas de raios X, com dez pacientes por sala. As imagens foram avaliadas pelos radiologistas dos serviços segundo o protocolo europeu. O kerma no ar na superfície de entrada foi estimado a partir da curva de rendimento do equipamento de raios X, que foi obtida utilizando câmara de ionização acoplada a um eletrômetro. Análise de variância foi realizada para verificar se a diferença entre os valores de kerma no ar na superfície de entrada é significativa. RESULTADOS: Os valores de kerma no ar na superfície de entrada variaram entre 0,05 e 0,26 mGy, com média 60% inferior ao nível de referência publicado na Portaria 453. Das imagens avaliadas, 98% atenderam acima de 65% dos critérios de qualidade. CONCLUSÃO: Para um padrão de qualidade da imagem, aceitável para o diagnóstico, verificou-se ampla variação do kerma no ar na superfície de entrada para pacientes-padrão. Isto demonstra a falta de padronização dos fatores de técnica e a existência de um potencial de redução do valor do kerma no ar na superfície de entrada. Abstract in english OBJECTIVE: To evaluate technical factors involved in posteroanterior chest radiography in standard patients, and correlating them with entrance surface air kerma rate and with the clinical images quality. MATERIALS AND METHODS: The present study was developed at three hospitals in Rio de Janeiro, Br [...] azil, involving a total of five x-ray rooms, with ten patients per room. The images were evaluated by the radiologists of the institutions, in accordance with the European protocol. The estimation of surface entrance air kerma rate was based on the x-ray equipment output curve obtained with an ionization chamber coupled with an electrometer. Variance analysis was performed to evaluate the significance of the difference between entrance surface air kerma rates. RESULTS: Entrance surface air kerma rates ranged between 0.05 and 0.26 mGy, with a mean value 60% lower than the reference level established by the Order (Portaria) 453. Among the images evaluated, 98% fulfilled > 65% of the images quality criteria. CONCLUSION: For a standard image quality that is acceptable for diagnosis purposes, a significant variation was observed in the entrance surface air kerma rate for standard patients, demonstrating the lack of technical factors standardization and a potential for decreasing the entrance surface air kerma rate.

  11. Air kerma strength calibration of 0.6 cc Farmer chamber for 192Ir HDR source

    International Nuclear Information System (INIS)

    One of the methods adopted by hospitals for the calibration of the HDR 192Ir source, in terms of Air Kerma Strength (AKS) is to use 0.6cc chamber at short source to chamber distances for measuring the air kerma rate at the chamber position and then compute the AKS using the appropriate correction factors. However, the 0.6 cc Farmer type chambers purchased by the users for the calibration of the HDR 192Ir source, are not generally provided with an HDR 192Ir calibration factor. With the result, many hospitals that have purchased the Farmer type chamber for the calibration of 192Ir HDR sources, use the 60Co calibration factor for this purpose. The use of 60Co calibration factor for the 192Ir HDR source would unnecessarily increase the uncertainty of the measured AKS. Again, because of the low chamber sensitivity, hospitals often use, source to chamber distances as small as a few cm for calibrating the 192Ir HDR source. In the absence of a rigid source-chamber positioning system, this can lead to several percent errors in AKS determination. Also, hospitals often don't take into account corrections for the room scatter or the fluence non-uniformity across the chamber, which further increase the uncertainty of the measured AKS

  12. Relationship between absorbed dose-rate in water and reference air kerma-rate for I-125 seeds

    International Nuclear Information System (INIS)

    To clinically utilize measured relative three-dimensional dose distribution about I-125 seeds in water, the absolute dose-rate in medium per source strength specification unit must be known at one point. Source strength is defined as air kerma-rate in free space along the transverse bisector of the source at a reference distance. The author has used the Monte Carlo method to calculate the dose-rate in water 1 cm from the source along its perpendicular bisector per unit reference air-kerma rate for model 6711, 6701, and 6702 seeds. The results indicate that published dose-rate constants overestimate this quantity by 10%-17%

  13. Kerma rate evaluation in the air in a room interventional cardiology; Avaliacao da taxa de Kerma no ar em uma sala de cardiologia intervencionista

    Energy Technology Data Exchange (ETDEWEB)

    Real, Jessica V.; Luz, Renata M. da, E-mail: jessica.real@pucrs.br, E-mail: renata.luz@pucrs.br [Hospital Sao Lucas (HSL/PUCRS), Porto Alegre, RS (Brazil); Fröhlich, Bruna D.; Silva, Ana Maria Marques da, E-mail: bruna.frohlich@acad.pucrs.br, E-mail: ana.marques@pucrs.br [Pontificia Universidade Catolica do Rio Grande do Sul (PUCRS), Porto Alegre, RS (Brazil)

    2014-07-01

    In recent years, the number of interventional cardiology procedures is increasing. However, due to the long time of fluoroscopy in these procedures, care teams can receive high doses of radiation. The radiation scattered by the patient is not uniform, and their assessment is of utmost importance. This study aimed to estimate and map the kerma rate in the air at the time of the gonads, in an interventional cardiology room, seeking to optimize the dose absorbed by individuals occupationally exposed to ionizing radiation. For data collection, the room was divided into quadrants of 1m{sup 2}, totaling 40 collection points. The simulator was positioned so that its entry surface was located in the interventional reference point. Were chosen the conditions that simulate angiography and angioplasty procedures performed in the service. The data were obtained for height of 1 meter, gonad region. The results obtained for kerma rates in air, in quadrants, show that higher measured values was in the vicinity of the X-ray tube. Has been found that the medical staff are more exposed, because of its location during the procedure, around the table. The law of the inverse square distance of the farthest points of the X-ray tube were verified.

  14. Effect of the diaphragm of free-air ionisation chamber for X-ray air-kerma measurements

    International Nuclear Information System (INIS)

    Free-air ionisation chambers are widely used at standards laboratories as primary standards for absolute measurements of air kerma in X-ray fields. The area of the diaphragm aperture of a free-air ionisation chambers is an important factor for absolute measurements because it defines the size of the X-ray beam incident on the free-air chamber. In this study, correction factors for the contribution of X rays transmitted through the diaphragm of a free-air ionisation chamber and those scattered from the surface of the diaphragm aperture are obtained by Monte Carlo simulation for two different sized free-air ionisation chambers and for various diaphragm aperture sizes, X-ray energies and source-to-chamber distances. (authors)

  15. Energy required to produce an ion pair in gas in the function of the measurement of kerma in air

    International Nuclear Information System (INIS)

    Average energy for producing an ion pair, mean W, was defined. So is its dependence on type of particles, relative partial pressure of the steam and relative humidity. Measurement methods were outlined. Energy W for different gases was presented in a Table, with an accent on the air. For the air, as the most interesting gas, the most recent determined value was given. Relationship between W, exposition X and air kerma K was explained (author)

  16. Sampling size in the verification of manufactured-supplied air kerma strengths

    International Nuclear Information System (INIS)

    Quality control mandate that the air kerma strengths (SK) of permanent seeds be verified, this is usually done by statistics inferred from 10% of the seeds. The goal of this paper is to proposed a new sampling method in which the number of seeds to be measured will be set beforehand according to an a priori statistical level of uncertainty. The results are based on the assumption that the SK has a normal distribution. To demonstrate this, the SK of each of the seeds measured was corrected to ensure that the average SK of its sample remained the same. In this process 2030 results were collected and analyzed using a normal plot. In our opinion, the number of seeds sampled should be determined beforehand according to an a priori level of statistical uncertainty

  17. The ratios of effective dose to entrance skin dose to the air kerma for some medical sources

    Energy Technology Data Exchange (ETDEWEB)

    Wise, K.N. [Australian Radiation Laboratory, Yallambie, VIC (Australia)

    1998-03-01

    Results are presented for the ratios of the effective dose to skin entrance dose and to air kerma for broad beams of radiation expected to be encountered by medical workers. These workers are monitored by the Personal Radiation Monitoring Service (PRMS) using thermoluminescent dosimeters worn at the front of the body to provide estimates of the entrance skin dose. Factors are given for converting estimates of entrance skin dose to effective dose as defined by the International Commission on Radiological Protection (ICRP 1991) for beams incident on the body by one of three modes-from the front of the subject, from the back of the subject or by rotation around the subject. Additional tables are also given to calculate effective dose for these beams from a measurement of air kerma free-in-air 4 figs., 9 tabs.

  18. Study and determination of the national dosimetric standards in terms of air kerma for X-rays radiation fields of low and medium-energies

    International Nuclear Information System (INIS)

    Progress in radiation protection and radiotherapy, and the increased needs in terms of accuracy lead national metrology institutes to improve the standard. For ionizing radiation, the standard is defined by an absolute instrument used for air kerma rate measurement. The aim of the thesis is to establish standards, in terms of air kerma for X-rays beams of low and medium-energies. This work enables to complement the standard beam range of the Laboratoire National Henri Becquerel (LNHB). Two free-air chambers have been developed, WK06 for medium-energy and WK07 for low-energy. The air-kerma rate is corrected by several correction factors. Some are determined experimentally; and the others by using Monte Carlo simulations. The uncertainty budget of the air-kerma rate at one standard deviation has been established. These dosimetric standards were compared with those of counterparts' laboratories and are consistent in terms of degree of equivalence. (author)

  19. Age-Dependent Dose in Organs per Unit Air Kerma Free-in-Air: Conversion Coefficients for Environmental Exposure

    International Nuclear Information System (INIS)

    Conversion coefficients from air kerma free-in-air to effective dose and dose in organs have been calculated for hermaphrodite 1, 5, 10, 15 year old children and adult anthropomorphic mathematical models. The 15 year old child phantom is also used as the adult female phantom. The irradiation geometry considered was the phantom standing on an almost infinite plane source, which is the geometry normally used for detector's calibration for environmental in situ measurements. The ADAM computer code has been modified to use the phantoms described by Cristy for the children phantoms, the adult male phantom is described in the ICRP Report 23. Thirty-six incident energies ranging from 10 keV to 10 MeV were selected for the incident radiation. (author)

  20. Product estimate of air kerma-area and the air kerma in the input surface of the skin of pediatric patients undergoing chest X-ray; Estimativa do produto kerma ar-area e do kerma ar na superficie de entrada da pele de pacientes pediatricos submetidos a radiografia de torax

    Energy Technology Data Exchange (ETDEWEB)

    Villa-Chan, Beatriz; Carvalho, Aline; Andrade, Marcos Ely A.; Barros, Vinicius S.M. de; Khoury, Helen J., E-mail: beatrizvillachan@gmail.com, E-mail: alinecx90@gmail.com, E-mail: marcos.ely@gmail.com, E-mail: vsmdbarros@gmail.com, E-mail: hjkhoury@gmail.com [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear

    2014-07-01

    The aim of this paper is to evaluate the entrance air kerma (Ka,e) and the product air kerma-area (Pka) for chest examinations performed with pediatric patients in a large public hospital of Recife. For this study 89 examinations of patient with ages from zero to 10 years old were evaluated. The results showed that the mean Ka,e values, for patients of 0-1 years old, 1-5 years old and 5-10 years old, were, respectively, 100 mGy, 120 mGy and 100 mGy. The Pka values for newborn patients range from 11,9 to 58,4 mGy.cm{sup 2}, for patients with 1 to 5 years old range from 17 to 192 mGy.cm{sup 2}, and from 30,4 to 136,2 mGy.cm{sup 2} for patients with ages from 5 to 10 years old. The differences in the Pka values are due the different dimensions of the radiation field. For the results its possible to conclude that the Pka values are high, in special for patients with ages from 1 to 5 years old, indicating that the collimation of the radiation field is not adequate. (author)

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

    An indirect comparison of the standards for air kerma of the D.I. Mendeleev Institute for Metrology (VNIIM), Russian Federation, and of the Bureau International des Poids et Mesures (BIPM) was carried out in the 60Co radiation beam of the BIPM in November 2009. The comparison result, based on the calibration coefficient for a transfer standard and expressed as a ratio of the VNIIM and the BIPM standards for air kerma, is 1.0008 with a combined standard uncertainty of 1.8 * 10-3. The degrees of equivalence between the VNIIM and the other participants in this BIPM.RI(I)-K1 key comparison have been calculated and the results are presented in the form of a matrix. A graphical presentation is also given. (authors)

  3. Comparison of the standards of air kerma of the LNMRI/IRD and the BIPM for 60Co ? rays

    International Nuclear Information System (INIS)

    A third comparison of the standards for air kerma of Laboratorio Nacional de Metrologia das Radiacoes Ionizantes/Institute de Radioprotecao e Dosimetria (LNMRI/IRD), Rio de Janeiro, Brazil and of the Bureau International des Poids et Mesures (BIPM) has been carried out in 60Co radiation. The comparison result is 1.0007 and demonstrates that the LNMRI/IRD and BIPM standards agree closely, as was the case for the previous comparisons in 1986 and 1996. (authors)

  4. Comparison of the standards of air kerma of the ENEA-INMRI and the BIPM for 60Co ? rays

    International Nuclear Information System (INIS)

    A new comparison of the standards for air kerma of the Istituto Nazionale di Metrologia delle Radiazioni Ionizzanti of the Ente per le Nuove Tecnologie, l'Energia e l'Ambiente, Italy (ENEA-INMRI) and of the Bureau International des Poids et Mesures (BIPM) has been carried out in 60Co radiation. The comparison result, expressed as a ratio of the ENEA and BIPM standards, is 1.0051 (0.0026). (authors)

  5. Comparison of the standards for air kerma of the NMIJ and the BIPM for 137Cs ? rays

    International Nuclear Information System (INIS)

    A first comparison of the standards of air kerma of the National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology (NMIJ/AIST) and of the Bureau International des Poids et Mesures (BIPM) has been carried out in 137Cs radiation. The comparison result is 1.0005 with a relative standard uncertainty of 2.8 x 10-3. This result indicates that the NMIJ and BIPM standards are in agreement within one standard uncertainty. (authors)

  6. Comparison of the standards for air kerma of the NMIJ and the BIPM for 60Co ? rays

    International Nuclear Information System (INIS)

    A first comparison of the standards for air kerma of the National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology (NMIJ/AIST) and of the Bureau International des Poids et Mesures (BIPM) has been carried out in 60Co radiation. It shows that the NMIJ and BIPM standards differ by 0.72 % with a relative standard uncertainty of 2.4 x 10-3. (authors)

  7. Entrance surface air kerma in x-ray systems for paediatric interventional cardiology: a national survey

    International Nuclear Information System (INIS)

    The aims of this work were to report the results of a national survey on entrance surface air kerma (ESAK) values for different phantom thicknesses and operation modes in paediatric interventional cardiology (IC) systems and to compare them with previous values. The national survey also offers suggested investigation levels (ILs) for ESAK in paediatric cardiac procedures. ESAK was measured on phantoms of 4-16 cm thickness of polymethyl methacrylate slabs. For low fluoroscopy mode (FM), ESAK rates ranged from 0.11 to 33.1 mGy min-1 and for high FM from 0.34 to 61.0 mGy min-1. For cine mode, values of ESAK per frame were from 1.9 to 78.2 ?Gy fr-1. The ILs were suggested as the third quartile of the values measured. This research showed lower ESAK values than in previous research, particularly for ESAK values in cine modes. This work represents a first step towards launching a national programme in paediatric dosimetry for IC procedures. (authors)

  8. Air kerma standardization for diagnostic radiology, and requirements proposal for calibration laboratories

    International Nuclear Information System (INIS)

    The demand for calibration services and quality control in diagnostic radiology has grown in the country since the publication of the governmental regulation 453, issued by the Ministry of Health in 1998. At that time, to produce results facing the new legislation, many laboratories used different standards and radiation qualities, some of which could be inadequate. The international standards neither supplied consistent radiation qualities and standardization for the different types of equipment available. This situation changed with the publication of the new edition of the IEC 61267 standard, published in 2005. A metrology network was created, but it is not yet accredited by the accreditation organism of the country, INMETRO. The objective of this work was to implement the standardization of the air kerma for the un attenuated qualities (RQR) of IEC 61267, and to develop a requirement proposal for instruments calibration laboratories. Results of interlaboratory comparisons demonstrate that the quantity is standardized and internationally traceable. A laboratory requirement proposal was finalized and it shall be submitted to INMETRO to be used as auxiliary normative document in laboratory accreditation. (author)

  9. Calculation of conversion factor of Kerma in the air for ambient dose equivalent in radiotherapy

    International Nuclear Information System (INIS)

    This work aims to estimate the average conversion factor of Kerma in air to H * (10) using photon beams coming from clinic linear accelerators, transmitted through concrete walls of a radiotherapic treatment room. The transmitted photon spectra by both 1 meter and 2 meters concrete walls, in an area of 40 x 40 cm2, were calculated when the primary beam impart in an angle of 0 deg. The (secondary) photon beams transmitted respectively by 0,5 meter, 1,0 meter, 1,0 meter and 2,0 meter concrete walls, after they scattered by an angle of 90 deg in a cylindric phantom inside the room, were also determined. Generally, 50 millions of histories were computed for each simulation made for the primary beam. For the 90 deg spread, the number of histories was 100 millions. The computational code used on this work was the MCNP4B. The most common clinic accelerators used on radiotheraphic treatments were used on this work CLINAC-4, CLINAC-6, CLINAC-18 and CLINAC-2500. From the spectra analysis obtained in this work, it was possible to dispose the conversion factor for realistic beams found in radiotherapeutic establishment. (author)

  10. Verification of air-kerma strength of 125I seed for permanent prostate implants in Japan

    International Nuclear Information System (INIS)

    To assure the physical quality of brachytherapy, we investigated the difference between measured and manufacturer's stated source strengths in a single model SourceTech Medical (STM) 1251 125I seed. A well-type ionization chamber with a single-seed holder was used to measure the source strength of 2412 125I seeds before implant in 34 patients. The air-kerma strength was 0.450 U for all cases. The mean source strength for each patient was measured and compared with the manufacturer's stated value. The deviation from the measured value was compared with the tolerance range of the American Association of Physicists in Medicine (AAPM) TG-56 report's recommendation. The measured source strength was higher than the manufacturer's stated value, with a median difference of 1% (range, -2% to 5%). Sixteen of the totals of 2412 seeds (0.7%) were more than 5% different from the manufacturer's stated value. The median standard deviation (SD) from the mean value was 2.2% (range, 1.1% to 2.5%) for all patients. This is the first report of a single-seed assay performed for the model STM1251 125I seed. In this study the manufacturer's stated strength agreed well with the measured value. Nevertheless, the advisability of performing a single-seed assay at every institution should be considered, by referring to the appropriate regulations; for example, those used in the United States. (author)

  11. NaI(Tl) scintillator detectors stripping procedure for air kerma measurements of diagnostic X-ray beams

    International Nuclear Information System (INIS)

    Air kerma is an essential quantity for the calibration of national standards used in diagnostic radiology and the measurement of operating parameters used in radiation protection. Its measurement within the appropriate limits of accuracy, uncertainty and reproducibility is important for the characterization and control of the radiation field for the dosimetry of the patients submitted to diagnostic radiology and, also, for the assessment of the system which produces radiological images. Only the incident beam must be considered for the calculation of the air kerma. Therefore, for energy spectrum, counts apart the total energy deposition in the detector must be subtracted. It is necessary to establish a procedure to sort out the different contributions to the original spectrum and remove the counts representing scattered photons in the detector’s materials, partial energy deposition due to the interactions in the detector active volume and, also, the escape peaks contributions. The main goal of this work is to present spectrum stripping procedure, using the MCNP Monte Carlo computer code, for NaI(Tl) scintillation detectors to calculate the air kerma due to an X-ray beam usually used in medical radiology. The comparison between the spectrum before stripping procedure against the reference value showed a discrepancy of more than 63%, while the comparison with the same spectrum after the stripping procedure showed a discrepancy of less than 0.2%

  12. Direct calibration of a reference standard against the air kerma strength primary standard, at 192Ir HDR energy

    International Nuclear Information System (INIS)

    The primary standard of low air kerma rate sources or beams, maintained at the Radiological Standards Laboratory (RSL) of the Bhabha Atomic Research Centre (BARC), is a 60 cm3 spherical graphite ionization chamber. A 192Ir HDR source was standardized at the hospital site in units of air kerma strength (AKS) using this primary standard. A 400 cm3 bakelite chamber, functioning as a reference standard at the RSL for a long period, at low air kerma rates (compared to external beam dose rates), was calibrated against the primary standard. It was seen that the primary standard and the reference standard, both being of low Z, showed roughly the same scatter response and yielded the same calibration factor for the 400 cm3 reference chamber, with or without room scatter. However, any likelihood of change in the reference chamber calibration factor would necessitate the re-transport of the primary standard to the hospital site for re-calibration. Frequent transport of the primary standard can affect the long-term stability of the primary standard, due to its movement or other extraneous causes. The calibration of the reference standard against the primary standard at the RSL, for an industrial type 192Ir source maintained at the laboratory, showed excellent agreement with the hospital calibration, making it possible to check the reference chamber calibration at RSL itself. Further calibration procedures have been developed to offer traceable calibration of the hospital well ionization chambers. (author)

  13. Determination of conversion factors from air kerma to operational dose equivalent quantities for low-energy X-ray spectra

    International Nuclear Information System (INIS)

    The conversion coefficients from air kerma to ICRU operational dose equivalent quantities for STUK's realisation of the X-radiation qualities N-15 to N-60 of the ISO narrow (N) spectrum series were determined by utilising X-ray spectrum measurements. The pulse-height spectra were measured using a planar high-purity germanium spectrometer and unfolded to fluence spectra using Monte Carlo generated data of the spectrometer response. To verify the measuring and unfolding method, the first and second half-value layers and the air kerma rate were calculated from the fluence spectra and compared with the values measured using an ionisation chamber. For each radiation quality, the spectrum was characterised by the parameters given in ISO 4037-1. The conversion coefficients from the air kerma to the ICRU operational quantities Hp(10), Hp(0.07), H'(0.07) and H*(10) were calculated using monoenergetic conversion coefficients at zero angle of incidence. The results are discussed with respect to ISO 4037-4, and compared with published results for low-energy X-ray spectra. (authors)

  14. Air kerma standardization for diagnostic radiology, and requirements proposal for calibration laboratories; Padronizacao da grandeza Kerma no ar para radiodiagnostico e proposta de requisitos para laboratorios de calibracao

    Energy Technology Data Exchange (ETDEWEB)

    Ramos, Manoel Mattos Oliveira

    2009-07-01

    The demand for calibration services and quality control in diagnostic radiology has grown in the country since the publication of the governmental regulation 453, issued by the Ministry of Health in 1998. At that time, to produce results facing the new legislation, many laboratories used different standards and radiation qualities, some of which could be inadequate. The international standards neither supplied consistent radiation qualities and standardization for the different types of equipment available. This situation changed with the publication of the new edition of the IEC 61267 standard, published in 2005. A metrology network was created, but it is not yet accredited by the accreditation organism of the country, INMETRO. The objective of this work was to implement the standardization of the air kerma for the un attenuated qualities (RQR) of IEC 61267, and to develop a requirement proposal for instruments calibration laboratories. Results of interlaboratory comparisons demonstrate that the quantity is standardized and internationally traceable. A laboratory requirement proposal was finalized and it shall be submitted to INMETRO to be used as auxiliary normative document in laboratory accreditation. (author)

  15. Conversion of Airborne Gamma ray Spectra to Ground Level Air Kerma Rates

    DEFF Research Database (Denmark)

    Bargholz, Kim; Korsbech, Uffe C C

    1997-01-01

    A new method for relating airborne gamma-ray spectra to dose rates and kerma rates at ground level is presented. Dependent on flying altitude 50 m to 125 m the method gives correct results for gamma energies above 250 keV respective 350 keV. At lower energies the method underestimate the dose or kerma rates; by having a large fraction of the ground level gamma-rays at energies below 350 keV special care should be taken at an interpretation of the results.

  16. Study and determination of the national dosimetric standards in terms of air kerma for X-rays radiation fields of low and medium-energies; Etude et realisation des references dosimetriques nationales en termes de kerma dans l'air pour les faisceaux de rayons X de basses et moyennes energies

    Energy Technology Data Exchange (ETDEWEB)

    Ksouri, W

    2008-12-15

    Progress in radiation protection and radiotherapy, and the increased needs in terms of accuracy lead national metrology institutes to improve the standard. For ionizing radiation, the standard is defined by an absolute instrument used for air kerma rate measurement. The aim of the thesis is to establish standards, in terms of air kerma for X-rays beams of low and medium-energies. This work enables to complement the standard beam range of the Laboratoire National Henri Becquerel (LNHB). Two free-air chambers have been developed, WK06 for medium-energy and WK07 for low-energy. The air-kerma rate is corrected by several correction factors. Some are determined experimentally; and the others by using Monte Carlo simulations. The uncertainty budget of the air-kerma rate at one standard deviation has been established. These dosimetric standards were compared with those of counterparts' laboratories and are consistent in terms of degree of equivalence. (author)

  17. Distribution of kerma rate in the air inside of hemodynamic room for typical projections of interventionist cardiology procedures

    International Nuclear Information System (INIS)

    The evaluation of dose to physicians involved in Interventional Cardiology (IC) is an extreme important matter due to the high and non-uniform distribution of dose values. The radiation control during each procedure is complex and the reasons for the high exposures have many different causes. Many international recommendations have already been written aiming the radiation protection optimization in IC. In Brazil, there is not any special orientation for the protection of those occupational persons, nor a specific legislation. The purpose of this work is to evaluate the air kerma rate at critical anatomic regions of the occupationally exposed staff that carry out IC procedures, in representative incidences in order to give subsidies for individual monitoring procedures implementation and to give more information about their radiation protection. The air kerma rate has been measured in the often used condition in the two more common IC procedures namely angiography and coronary angioplasty, using an adult patient simulator irradiated under RAO, LAO and AP projections for fluoro and digital acquisition modes. The measurements have been made in 45 points around the examination table at 5 different representatives heights of: eyes lens, thorax, hands, gonads and knees. AP projection shows the smaller scattered radiation contributions and a more homogeneous exposure distribution. The digital acquisition mode gives air kerma rates about 4 times higher than fluoro mode for LAO projection in the position occupied by the interventionist doctor, the anesthetist and the nursing staff. The most critical anatomic regions are: knees and gonads (without protection). On the physician hands position, values as high as 5 mGy/h have been measured, which can overpass, depending on the number of procedures done, the individual occupational annual limit. Therefore, in IC it is necessary to implement additional protection tools, elaborate safety guides (based on international experiences and recommendations) and establish a permanent radiation protection training programs. (author)

  18. Comparison of the standards of air kerma of the ENEA-INMRI and the BIPM for 137Cs gamma rays

    International Nuclear Information System (INIS)

    A comparison of the standards of air kerma of the Istituto Nazionale di Metrologia delle Radiazioni Ionizzanti of the Ente per le Nuove Tecnologie, l'Energia e l'Ambiente, Italy (ENEA-INMRI) and of the Bureau International des Poids et Mesures (BIPM) was carried out in 137Cs radiation in 1998. The comparison result, updated for changes in the standards in 2003 and 2009, is 0.9927 (0.0067) and demonstrates that the ENEA-INMRI and BIPM standards are in agreement within the uncertainties. (authors)

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

    International Nuclear Information System (INIS)

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

  20. Measurement of conversion coefficients between air Kerma and personal dose equivalent and backscatter factors for diagnostic X-ray beams

    International Nuclear Information System (INIS)

    Two sets of quantities are import in radiological protection: the protection and operational quantities. Both sets can be related to basic physical quantities such as kerma through conversion coefficients. For diagnostic x-ray beams the conversion coefficients and backscatter factors have not been determined yet, those parameters are need for calibrating dosimeters that will be used to determine the personal dose equivalent or the entrance skin dose. Conversion coefficients between air kerma and personal dose equivalent and backscatter factors were experimentally determined for the diagnostic x-ray qualities RQR and RQA recommended by the International Electrotechnical Commission (IEC). The air kerma in the phantom and the mean energy of the spectrum were measured for such purpose. Harshaw LiF-100H thermoluminescent dosemeters (TLD) were used for measurements after being calibrated against an 180 cm3 Radcal Corporation ionization chamber traceable to a reference laboratory. A 300 mm x 300 mm x 150 mm polymethylmethacrylate (PMMA) slab phantom was used for deep-dose measurements. Tl dosemeters were placed in the central axis of the x-ray beam at 5, 10, 15, 25 and 35 mm depth in the phantom upstream the beam direction Another required parameter for determining the conversion coefficients from was the mean energy of the x-ray spectrum. The spectroscopy of x-ray beams was done with a CdTe semiconductor detector that was calibrated with 133 Ba, 241 Am and 57 Co radiation sources. Measurements of the x-ray spectra were carried out for all RQR and RQA IEC qualities. Corrections due to the detector intrinsic efficiency, total energy absorption, escape fraction of the characteristic x-rays, Compton effect and attenuation in the detector were done aiming an the accurate determination of the mean energy. Measured x-ray spectra were corrected with the stripping method by using these response functions. The typical combined standard uncertainties of conversion coefficients and backscatter factors were 12% and 6% respectively. (author)

  1. Comparison of the standards for air kerma of the VNIIM and the BIPM for 60Co gamma radiation

    Science.gov (United States)

    Kessler, C.; Allisy-Roberts, P. J.; Oborin, A. V.; Villevalde, A. Y.

    2011-01-01

    An indirect comparison of the standards for air kerma of the D I Mendeleyev Institute for Metrology (VNIIM), Russian Federation, and of the Bureau International des Poids et Mesures (BIPM) was carried out in the 60Co radiation beam of the BIPM in November 2009. The comparison result, based on the calibration coefficient for a transfer standard and expressed as a ratio of the VNIIM and the BIPM standards for air kerma, is 1.0008 with a combined standard uncertainty of 1.8 × 10-3. The degrees of equivalence between the VNIIM and the other participants in this BIPM.RI(I)-K1 key comparison have been calculated and the results are presented in the form of a matrix. A graphical presentation is also given. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI Section I, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

  2. European inter-comparison of Monte Carlo codes users for the uncertainty calculation of the kerma in air beside a caesium-137 source

    International Nuclear Information System (INIS)

    Within the frame of the CONRAD European project (Coordination Network for Radiation Dosimetry), and more precisely within a work group paying attention to uncertainty assessment in computational dosimetry and aiming at comparing different approaches, the authors report the simulation of an irradiator containing a caesium 137 source to calculate the kerma in air as well as its uncertainty due to different parameters. They present the problem geometry, recall the studied issues (kerma uncertainty, influence of capsule source, influence of the collimator, influence of the air volume surrounding the source). They indicate the codes which have been used (MNCP, Fluka, Penelope, etc.) and discuss the obtained results for the first issue

  3. Comparison BIPM.RI(I)-K8 of high dose-rate Ir-192 brachytherapy standards for reference air kerma rate of the VSL and the BIPM

    DEFF Research Database (Denmark)

    Alvarez, J.T.; De Pooter, J.A.

    2014-01-01

    An indirect comparison of the standards for reference air kerma rate for 192Ir high dose rate brachytherapy sources of the Dutch Metrology Institute (VSL), The Netherlands, and of the Bureau International des Poids et Mesures (BIPM) was carried out at the VSL in November 2009. The comparison result, based on the calibration coefficients for a transfer standard and expressed as a ratio of the VSL and the BIPM standards for reference air kerma rate, is 0.9873 with a combined standard uncertainty of 0.0061.

  4. Assessment of protocols in cone-beam CT with symmetric and asymmetric beams usingeffective dose and air kerma-area product.

    Science.gov (United States)

    Batista, Wilson Otto; Soares, Maria Rosangela; de Oliveira, Marcus V L; Maia, Ana F; Caldas, Linda V E

    2015-06-01

    This study aims to evaluate and compare protocols with similar purposes in a cone beam CT scanner using thermoluminescent dosimeter (TLD) and the air kerma-area product (PKA) as the kerma index. The measurements were performed on two protocols used to obtain an image of the maxilla-mandible using the equipment GENDEX GXCB 500: Protocol [GX1] extended diameter and asymmetric beam (14cm×8.5cm-maxilla/mandible) and protocol [GX2] symmetrical beam (8.5cm×8.5cm-maxillary/mandible). LiF dosimeters inserted into a female anthropomorphic phantom were used. For both protocols, the value of PKA was evaluated using a PTW Diamentor E2 meter and the multimeter Radcal Rapidose system. The results obtained for the effective dose/PKA were separated by protocol image. [GX1]: 44.5µSv/478mGycm(2); [GX2]: 54.8µSv/507mGycm(2). Although the ratio of the diameters (14cm/8.5cm)=1.65, the ratio of effective dose values (44.5µSv/54.8µSv)=0.81, that is, the effective dose of the protocol with extended diameter is 19% smaller. The PKA values reveal very similar results between the two protocols. For the cases where the scanner uses an asymmetric beam to obtain images with large diameters that cover the entire face, there are advantages from the point of view of reducing the exposure of patients when compared to the use of symmetrical beam and/or to FOV images with a smaller diameter. PMID:25620114

  5. Dosimetric characteristics, air-kerma strength calibration and verification of Monte Carlo simulation for a new ytterbium-169 brachytherapy source

    International Nuclear Information System (INIS)

    Ytterbium-169 (169Yb) is a promising new isotope for brachytherapy with a half life of 32 days and an average photon energy of 93 KeV. It has an Ir-192-equivalent dose distribution in water but a much smaller half-value layer in lead (0.2 mm), affording improved radiation protection and customized shielding of dose-limiting anatomic structures. The goals of this study are to: (a) experimentally validate Monte Carlo photon transport dose-rate calculations for this energy range, (b) to develop a secondary air-kerma strength standard for 169Yb, and (c) to present essential treatment planning data including the transverse-axis dose-rate distribution and dose correction factors for a number of local shielding materials. Several interstitial 169Yb sources (type 6) and an experimental high dose-rate source were made available for this study. Monte Carlo photon-transport (MCPT) simulations, based upon validated geometric models of source structure, were used to calculate dose rates in water. To verify MCPT predictions, the transverse-axis dose distribution in homogeneous water medium was measured using a silicon-diode detector. For use in designing shielded applicators, heterogeneity correction factors (HCF) arising from small cylindrical heterogeneities of lead, aluminum, titanium, steel and air were measured in a water medium. Finally, to provide a sound experimental basis for comparing experimental and theoretical dose-rate distributions, the air-kerma strength of the sources was measured using a calibrated ion chamber. To eliminate the influence of measurement artifacts on the comparison of theory and measurement, simulated detector readings were compared directly to measured diode readings. The final data are presented in the format endorsed by the Interstitial Collaborative Working Group. 33 refs., 8 figs., 3 tabs

  6. Calculation of the correction factors for the primary standard of kerma in the air at the LNMRI-IRD, Rio de Janeiro, Brazil

    International Nuclear Information System (INIS)

    In order to determine the primary standardization in terms of kerma in the air, a graphite ionization chamber is used for calculation some correction factors. A program was elaborated, using the Monte Carlo Penelope for simulate the CC01-110 at the LNMRI/IRD, Rio de Janeiro, Brazil

  7. Distribution of kerma rate in the air inside of hemodynamic room for typical projections of interventionist cardiology procedures; Distribuicao da taxa de kerma no ar em uma sala de hemodinamica para projecoes tipicas de procedimentos de cardiologia intervencionista

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, Mirtha Elizabet Gamarra

    2008-07-01

    The evaluation of dose to physicians involved in Interventional Cardiology (IC) is an extreme important matter due to the high and non-uniform distribution of dose values. The radiation control during each procedure is complex and the reasons for the high exposures have many different causes. Many international recommendations have already been written aiming the radiation protection optimization in IC. In Brazil, there is not any special orientation for the protection of those occupational persons, nor a specific legislation. The purpose of this work is to evaluate the air kerma rate at critical anatomic regions of the occupationally exposed staff that carry out IC procedures, in representative incidences in order to give subsidies for individual monitoring procedures implementation and to give more information about their radiation protection. The air kerma rate has been measured in the often used condition in the two more common IC procedures namely angiography and coronary angioplasty, using an adult patient simulator irradiated under RAO, LAO and AP projections for fluoro and digital acquisition modes. The measurements have been made in 45 points around the examination table at 5 different representatives heights of: eyes lens, thorax, hands, gonads and knees. AP projection shows the smaller scattered radiation contributions and a more homogeneous exposure distribution. The digital acquisition mode gives air kerma rates about 4 times higher than fluoro mode for LAO projection in the position occupied by the interventionist doctor, the anesthetist and the nursing staff. The most critical anatomic regions are: knees and gonads (without protection). On the physician hands position, values as high as 5 mGy/h have been measured, which can overpass, depending on the number of procedures done, the individual occupational annual limit. Therefore, in IC it is necessary to implement additional protection tools, elaborate safety guides (based on international experiences and recommendations) and establish a permanent radiation protection training programs. (author)

  8. Development of a primary standard in terms of reference air kerma rate for 125I brachytherapy seeds

    International Nuclear Information System (INIS)

    The LNE-LNHB is currently developing the French primary standard in low dose rate brachytherapy. The method is based on a free-in-air ionization chamber for 125I seeds. Such sealed radioactive sources are used for treatment of ophthalmic and prostatic cancers. Low dose rate brachytherapy seeds are of small size, about 0.8 mm in diameter and 4.5 mm in length, cylindrically shaped and of complex internal design. This causes an anisotropy of emission in both planes, longitudinal and transverse. The reference air kerma rate is theoretically defined in this latter plane at a point positioned in a small volume of air at a one meter distance from the source center, the source and the air volume being surrounded by vacuum. To overcome the difficulties linked to a transversal anisotropic emission and to an expected low signal-to-noise ratio, a circular ring-shaped free-in-air ionization chamber has been designed. The 125I source seed is placed at the center of this ring detector in a tube of a low attenuated material. This paper presents an extended characterization of the circular ring-shaped free-in-air ionisation chamber. This one deals with the signal-to-noise ratio optimization, the detection volume assessment (taking into account the electric field distribution within it) and the sensitivity of the measurement linked to the source positioning. Furthermore, the correction factors to apply to the measurement results are described and their estimation using Monte Carlo codes of particle transport are presented for the Bebig iodine seed sources, referenced I125 S16

  9. Attenuation factors in terms of air kerma to ambient dose equivalent and effective dose for diagnostic X rays rooms

    International Nuclear Information System (INIS)

    In the present study, the attenuation of the quantities fluence and air kerma free-in-air by various layers of lead was compared with that of the quantities effective dose, E, and ambient dose equivalent, H*(d). This work aims to calculate the attenuation factors from 50 kV, 125 kV and 150 kV of X ray beams used for medical diagnostic, after transmission through barriers of lead. The X ray qualities used were those recommended by the Birch and Marshall for primary diagnostic X rays. Several lead layers were irradiated with a 50 cm x 50 cm field of primary X ray spectra. The transmitted spectra were calculated to obtain the attenuation factors for beams found in radiodiagnostic services. The calculations were done using the MCNPX Monte Carlo code and voxel model MAX. The values obtained were compared with data derived from the literature. In addition, attenuation factors for X ray qualities after penetration of lead layers were studied to get data which might be of interest in shielding of diagnostic rooms. (author)

  10. Key comparison BIPM.RI(I)-K5 of the air-kerma standards of the PTB, Germany and the BIPM in 137Cs gamma radiation

    Science.gov (United States)

    Kessler, C.; Burns, D. T.; Büermann, L.

    2014-01-01

    A direct comparison of the standards for air kerma of the Physikalisch-Technische Bundesanstalt (PTB), Germany and of the Bureau International des Poids et Mesures (BIPM) was carried out in the 137Cs radiation beam of the BIPM in March 2014. The comparison result, evaluated as a ratio of the PTB and the BIPM standards for air kerma, is 1.0024 with a combined standard uncertainty of 2.7 × 10-3. The results are analysed and presented in terms of degrees of equivalence for entry in the BIPM key comparison database. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  11. Key comparison BIPM.RI(I)-K1 of the air-kerma standards of the PTB, Germany and the BIPM in 60Co gamma radiation

    Science.gov (United States)

    Kessler, C.; Burns, D. T.; Büermann, L.

    2014-01-01

    A direct comparison of the standards for air kerma of the Physikalisch-Technische Bundesanstalt (PTB), Germany and of the Bureau International des Poids et Mesures (BIPM) was carried out in the 60Co radiation beam of the BIPM in March 2014. The comparison result, evaluated as a ratio of the PTB and the BIPM standards for air kerma, is 1.0036 with a combined standard uncertainty of 1.7 × 10-3. The results are analysed and presented in terms of degrees of equivalence for entry in the BIPM key comparison database. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  12. Comparison BIPM.RI(I)-K8 of high dose-rate Ir-192 brachytherapy standards for reference air kerma rate of the PTB and the BIPM

    Science.gov (United States)

    Kessler, C.; Allisy-Roberts, P. J.; Selbach, H. J.

    2015-01-01

    An indirect comparison of the standards for reference air kerma rate (RAKR) for 192Ir high dose rate (HDR) brachytherapy sources of the Physikalisch-Technische Bundesanstalt (PTB), Germany, and of the Bureau International des Poids et Mesures (BIPM) was carried out at the PTB in September 2011. The comparison result, based on the calibration coefficients for a transfer standard and expressed as a ratio of the PTB and the BIPM standards for reference air kerma rate, is 1.0003 with a combined standard uncertainty of 0.0099. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  13. Key comparison BIPM.RI(I)-K2 of the air-kerma standards of the NMIJ, Japan and the BIPM in low-energy x-rays

    International Nuclear Information System (INIS)

    A key comparison has been made between the air-kerma standards of the NMIJ and the BIPM in the low-energy x-ray range. The results show the standards to be in agreement at the level of the standard uncertainty for the comparison of 3.0 parts in 103. The results are analysed and presented in terms of degrees of equivalence, suitable for entry in the BIPM key comparison database. (authors)

  14. Comparison of the air-kerma standards of the ENEA-INMRI and the BIPM in the low-energy X-ray range

    International Nuclear Information System (INIS)

    A direct comparison has been made between the air-kerma standards of the ENEA-INMRI and the BIPM in the low-energy x-ray range. The results show the standards to be in agreement to around 0.35 % at reference beam qualities up to 50 kV. Measurements were also made at the 80 kV quality in order to estimate the electron-loss correction for the ENEA standard at this quality. (authors)

  15. Key comparison BIPM.RI(I)-K7 of the air-kerma standards of the BEV, Austria and the BIPM in mammography x-rays

    International Nuclear Information System (INIS)

    A first key comparison has been made between the air-kerma standards of the BEV and the BIPM in mammography x-ray beams. The results show the standards to be in agreement at the level of the combined standard uncertainty of 3.4 parts in 103. The results are analysed and presented in terms of degrees of equivalence for entry in the BIPM key comparison database. (authors)

  16. Key comparison BIPM.RI(I)-K2 of the air-kerma standards of the BEV, Austria and the BIPM in low-energy x-rays

    International Nuclear Information System (INIS)

    A key comparison has been made between the air-kerma standards of the BEV and the BIPM in the low-energy x-ray range. The results show the standards to be in agreement at the level of the combined standard uncertainty of 4.7 parts in 103. The results are analysed and presented in terms of degrees of equivalence, suitable for entry in the BIPM key comparison database. (authors)

  17. Key comparison BIPM.RI(I)-K3 of the air-kerma standards of the BEV, Austria and the BIPM in medium-energy x-rays

    International Nuclear Information System (INIS)

    A key comparison has been made between the air-kerma standards of the BEV, Austria and the BIPM in the medium-energy x-ray range. The results show the standards to be in general agreement at the level of the expanded uncertainty (k = 2) of the comparison of 6.4 parts in 103. The results are analysed and presented in terms of degrees of equivalence, suitable for entry in the BIPM key comparison database. (authors)

  18. Measuring instruments of the Physikalisch-Technische Bundesanstalt for realization of the units of the dosimetric quantities standard ion dose, photon-equivalent dose and air-kerma

    International Nuclear Information System (INIS)

    The realization of the units of the dosimetric quantities exposure, air-kerma and photon-equivalent dose is an important task of the Physikalisch-Technische Bundesanstalt. The report describes the measuring instruments and other technical equipment as well as the determination of the numerous corrections needed. All data and correction factors required for the realization of the units mentioned above are given in many diagrams and tables. (orig.)

  19. Monte Carlo aided room scatter studies in the primary air kerma strength standardization of a remote afterloading 192Ir HDR source

    International Nuclear Information System (INIS)

    Corrections for room scatter, [ksc(d, H)]RM, were derived using Monte Carlo methods for rooms of various sizes, including the brachytherapy treatment room, in which primary air kerma strength standardization of a remote afterloading microSelectron 192Ir HDR source was carried out, using a 60 cm3 spherical graphite ion chamber. It was observed that for a given source-to-floor height, H, the air kerma rate due to room scatter was found to be decreasing with increase in source-to-detector distance, d, whereas it is assumed to be constant in the experimental determination (multiple-distance method) of the air kerma strength (AKS). Irrespective of the room size considered in the present study and when H=100 cm, the assumption of 'constant room scatter' for d=50, 75 and 100 cm resulted in overestimation of the AKS by about 1%. However, when d was in the range 13-25 cm, it was only 0.20%. The room scatter correction for the shadow cone method was also computed and the result showed that no additional correction was required on account of forward scatter from the cone. Further, at larger d (50-100 cm), the number of low-energy photons (40-200 keV) relative to the total number of photons was found to be very significant, which may be useful to revisit the Spencer-Attix cavity theory. (author)

  20. Fluence non-uniformity effects in air kerma determination around brachytherapy sources

    International Nuclear Information System (INIS)

    In ionization chamber dosimetry close to brachytherapy sources, the non-uniform photon fluence in the vicinity of the air cavity of the ionization chamber must be corrected for. In this paper, experimentally determined relative non-uniformity correction factors are determined for a TW23331 chamber and a number of Farmer-type chambers. It is concluded that the 'anisotropic' theory of Bielajew agrees better with the experimental results than the 'isotropic' theory of Kondo and Randolph. The experiments show that neither the material choice nor the radius of the central electrode have any significant effect on the non-uniformity correction factors. Experiments on the wall-material dependence in the non-uniformity correction factor, which is predicted by the anisotropic theory, were inconclusive. Parameters for the Farmer-type chambers for calculation of theoretical non-uniformity correction factors are given. Data to derive anisotropic fluence non-uniformity correction factors are given in tabular form. An error n the Kondo and Randolph equations is reported and the corrected equations presented. (author)

  1. 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

  2. Revised comparison of the standards for air kerma of the ENEA-INMRI and the BIPM for 60Co gamma rays

    International Nuclear Information System (INIS)

    In 1998 a comparison of the standards of air kerma of the Istituto Nazionale di Metrologia delle Radiazioni Ionizzanti of the Ente per le Nuove Tecnologie, l'Energia e l'Ambiente, Italy (ENEA-INMRI) and of the Bureau International des Poids et Mesures (BIPM) was carried out in 60Co radiation. The comparison result, declared in 2003, is 1.0044 (0.0026) and demonstrates that the ENEA-INMRI and BIPM standards are in agreement within the expanded uncertainty (k = 2). (authors)

  3. Comparison of the air-kerma standards of the NPL and the BIPM in the low and medium-energy X-ray ranges

    International Nuclear Information System (INIS)

    The air-kerma standards of the NPL and the BIPM have been compared in the low- and medium-energy x-ray ranges. The results for the low-energy comparison show the standards to be in agreement at the level of one standard uncertainty. At medium energies a slight trend with radiation quality is evident, with agreement at the level of one standard uncertainty for 100 kV rising to over two standard uncertainties for 250 kV. In relation to previous comparisons, the good stability of the standards over a period of twenty years is demonstrated. (authors)

  4. Comparison of the air kerma standards of the NIST and the BIPM in the low-energy X-ray range

    International Nuclear Information System (INIS)

    A direct comparison has been made between the air-kerma standards of the NIST and the BIPM in the low-energy x-ray range. The results show the standards to be in agreement to around 0.5 % at reference beam qualities up to 50 kV and at 100 kV. Agreement at the 80 kV quality is less satisfactory, which may be attributed to an incorrect value for the electron-loss correction for the NIST standard at this quality. (authors)

  5. Proposed specification for a primary standard of air kerma for sup 6 sup 0 Co, sup 1 sup 3 sup 7 Cs and sup 1 sup 9 sup 2 Ir gamma-ray sources

    CERN Document Server

    Angliss, R; Nutbrown, R

    2001-01-01

    The three cavity chambers, the mean response of which constitutes the primary standard of air kerma for sup 6 sup 0 Co and sup 1 sup 3 sup 7 Cs gamma-rays in the United Kingdom, have been in continuous, almost daily, use at the National Physical Laboratory (NPL) since 1956. These chambers were initially designed for use with 2 MV X-rays at therapy level air kerma rates. However since 1978 they have also been used for protection level air kerma rates, initially, with X-rays generated at 1 MV and 2 MV and more recently with sup 6 sup 0 Co and sup 1 sup 3 sup 7 Cs gamma-rays. They have been used for therapy level air kerma calibrations with sup 6 sup 0 Co gamma-rays since 1997 following the demise of the NPL 2 MV Van de Graaff generator. This report describes the proposals for a new primary standard and the methods that will be used to give a better performance than the present standard when used with air kerma rates from as high as 1 Gy min sup - sup 1 down to 10 mGy hr sup - sup 1. The design will also seek to...

  6. Construction of a laboratory for the implantation of primary standardization of the magnitude kerma in the air for the X-ray beams used in mammography; Construcao de um laboratorio para a implantacao da padronizacao primaria da grandeza kerma no ar para os feixes de raios X empregados em mamografia

    Energy Technology Data Exchange (ETDEWEB)

    Cardozo, W.L.; Magalhes, L.A.A.M.F.; Peixoto, J.G.P., E-mail: wagnerlc@ird.gov.b [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Lab. Nacional de Metrologia das Radiacoes Ionizantes (LNMRI)

    2009-07-01

    Aiming to diminish the uncertainty in each phase of the metrological chain, and the uncertainty in dosimetry processed at the X-ray beam applied in the mammography, is necessary that the LNMRI/IRD to develop a reference primary standard for the absolute form to the magnitude kerma in the air

  7. Calculation of the correction factors for the primary standard of kerma in the air at the LNMRI-IRD, Rio de Janeiro, Brazil; Calculo de fatores de correcao para o padrao primario em kerma no ar do LNMRI-IRD, Rio de Janeiro, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Cosme Norival Mello da, E-mail: cosme@ird.gov.b [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Lab. Nacional de Metrologia das Radiacoes Ionizantes (LNMRI)

    2009-07-01

    In order to determine the primary standardization in terms of kerma in the air, a graphite ionization chamber is used for calculation some correction factors. A program was elaborated, using the Monte Carlo Penelope for simulate the CC01-110 at the LNMRI/IRD, Rio de Janeiro, Brazil

  8. Kerma in the air at entry surface in thorax pediatric examinations at public hospital in Parana, Brazil; Kerma no ar na superficie de entrada em exames pediatricos de torax em hospital publico no Parana, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Amanda; Porto, Lorena; Bunick, Ana; Paschuk, Sergei; Denyak, Valeriy, E-mail: schelin@utfpr.edu.b [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil); Schelin, Hugo; Tilly, Joao, E-mail: joao.tilly@derax.com.b [DERAX Desenvolvimento Radiologico, Curitiba, PR (Brazil); Khoury, Helen, E-mail: hjkhoury@gmail.co [Universidade Federal de Pernambuco (DOIN/UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear. Grupo de Dosimetria e Instrumentacao Nuclear; Ferreira, Jose [Universidade Estadual do Oeste do Parana (UNIOESTE), Cascavel, PR (Brazil)

    2011-07-01

    This work consisted in the evaluation of the entrance skin air kerma (ESAK) in pediatric chest x-ray examinations. A study of 186 exams in anterior-posterior, posterior-anterior and lateral projections was carried out for patients with ages ranging from 0 to 15 years. The ESAK was measured with the DoseCal software and Li-Fl thermoluminescent dosimeters. The results were compared with measurements done recently at the same place and with the reference dose values established by the European Community. It was observed that the optimization of the technique and the routine changes suggested in the previous study were not maintained. The charge (mAs) and the ESAK values found in the present study were much higher than the previous one, and the voltage (kVp) values found was lower. The results suggest that the implementation of the Quality Assurance Program could adequate these parameters to the established levels and keep the pediatric examinations more uniform. (author)

  9. Calculation of conversion factor of Kerma in the air for ambient dose equivalent in radiotherapy; Calculo dos fatores de conversao de Kerma no ar para equivalente de dose ambiental em radioterapia

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Marco Antonio Frota

    2000-03-01

    This work aims to estimate the average conversion factor of Kerma in air to H {sup *} (10) using photon beams coming from clinic linear accelerators, transmitted through concrete walls of a radiotherapic treatment room. The transmitted photon spectra by both 1 meter and 2 meters concrete walls, in an area of 40 x 40 cm{sup 2}, were calculated when the primary beam impart in an angle of 0 deg. The (secondary) photon beams transmitted respectively by 0,5 meter, 1,0 meter, 1,0 meter and 2,0 meter concrete walls, after they scattered by an angle of 90 deg in a cylindric phantom inside the room, were also determined. Generally, 50 millions of histories were computed for each simulation made for the primary beam. For the 90 deg spread, the number of histories was 100 millions. The computational code used on this work was the MCNP4B. The most common clinic accelerators used on radiotheraphic treatments were used on this work CLINAC-4, CLINAC-6, CLINAC-18 and CLINAC-2500. From the spectra analysis obtained in this work, it was possible to dispose the conversion factor for realistic beams found in radiotherapeutic establishment. (author)

  10. Estimation of mean-glandular dose from monitoring breast entrance skin air kerma using a high sensitivity metal oxide semiconductor field effect transistor (MOSFET) dosimeter system in mammography

    International Nuclear Information System (INIS)

    Estimation of mean-glandular dose (MGD) has been investigated in recent years due to the potential risks of radiation-induced carcinogenesis associated with the mammographic examination for diagnostic radiology. In this study, a new technique for immediate readout of breast entrance skin air kerma (BESAK) using high sensitivity MOSFET dosimeter after mammographic projection was introduced and a formula for the prediction of tube output with exposure records was developed. A series of appropriate conversion factors was applied to the MGD determination from the BESAK. The study results showed that signal response of the high sensitivity MOSFET exhibited excellent linearity within mammographic dose ranges, and that the energy dependence was less than 3% for each anode/filter combination at the tube potentials 25-30 kV. Good agreement was observed between the BESAK and the tube exposure output measurement for breasts thicker than 30 mm. In addition, the air kerma estimated from our prediction formula provided sufficient accuracy for thinner breasts. The average MGD from 120 Asian females was 1.5 mGy, comparable to other studies. Our results suggest that the high sensitivity MOSFET dosimeter system is a good candidate for immediately readout of BESAK after mammographic procedures

  11. Comparisons of the standards for air kerma of the PTB and the BIPM for 60Co and 137Cs gamma radiation

    International Nuclear Information System (INIS)

    Direct comparisons of the standards for air kerma of the Physikalisch-Technische Bundesanstalt (PTB, Germany) and of the Bureau International des Poids et Mesures (BIPM) were carried out in the 60Co and 137 Cs radiation beams of the BIPM in 2000. The results, expressed as ratios of the PTB and the BIPM standards for air kerma, indicate a relative difference in 60Co of 9.9 x 10-3 with a combined standard uncertainty of 1.8 x 10-3, and in 137Cs of 6.4 x 10-3 with a combined standard uncertainty of 2.8 x 10-3. The earlier comparisons in 60Co ? rays made in 1971 (direct) and 1989 (indirect) resulted in an agreement of the two standards within 2 x 10-3. The differences obtained now are due to the application of new correction factors for wall effects and point source non-uniformity of the beam, kwall and kpn, for the PTB standards, which were calculated using Monte Carlo methods. (authors)

  12. Intercomparison of absorbed dose to water and air-kerma based dosimetry protocols for photon and electron beams

    International Nuclear Information System (INIS)

    Full text: During the last three decades the International Atomic Energy Agency (IAEA), the American Association of Physicists in Medicine (AAPM) and organizations from various countries have published Codes of Practice (CoP) and dosimetry protocols for the calibration of high-energy photon and electron beams. They are based on the air-kerma or exposure calibration factor of an ionization chamber in a 60Co gamma ray beam and formalism for the determination of absorbed dose to water in reference conditions. In recent years, the IAEA (IAEA TRS-398) and the AAPM (AAPM TG-51) have published new external beam dosimetry protocols that are based on the use of an ionization chamber calibrated in terms of absorbed dose to water in a standards laboratory's reference quality beam. These two new protocols follow those by the German Standard DIN, the British IPSM and the IAEA CoP for plane-parallel chambers, which have discussed and implemented the procedures for the determination of absorbed dose-to-water based on standards of absorbed dose-to-water. Since the publication of these protocols and CoPs, many comparisons, theoretical as well as experimental, between them have been published in the literature providing valuable information about the sources of similarities and discrepancies that exist among them. For example, the differences in the basic data for photon and electron beams included in the various IAEA CoPs are very small for the second edition of TRS-277 for photons, TRS-381 for electrons and TRS-398. In these cases the data changes posed by the adoption of TRS-398 are within about ±0.3% for the most commonly used energies. When implementing TRS-398 in these cases, the main difference will arise from the transition from Kair to Dw standards. For example, experimental comparison of absorbed doses between TRS-398 and TRS-277 for photons show an average difference of about 0.3% for most commonly used energies with a maximum difference of about 1% at a TPR20,10 value of 0.80; for electrons a maximum difference of about 1% is observed between TRS-398 and TRS-381 and about 1.8% between TRS-398 and TRS277 for energies ranging from 6-18 MeV. The comparison of TRS-398 with TG-51 reveals that photon beam dosimetry agrees within about ±0.3% for most commonly used energies. For electron beam dosimetry, comparison of TRS-398 with TG-51 reveals agreement within about ±0.4% for cylindrical chambers for energies above 10 MeV approximately; however, for plane-parallel chambers, differences of almost up to 2% is observed between the two protocols. On the other hand, the agreement for these chambers when cross-calibration procedures are used is excellent. This talk will provide a comprehensive review of intercomparisons of all these protocols. The reasons for the discrepancies between theory and experiments will be discussed terms of the combined effect of small data differences and the influence of ND,w/NK for the various chamber types. (author)

  13. KERMA ratios in pediatric CT dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Huda, Walter [Medical University of South Carolina (MUSC), Department of Radiology and Radiological Science, Charleston, SC (United States); Ogden, Kent M.; Lavallee, Robert L.; Roskopf, Marsha L.; Scalzetti, Ernest M. [SUNY Upstate Medical University, Department of Radiology, Syracuse, NY (United States)

    2012-05-15

    Patient organ doses may be estimated from CTDI values. More accurate estimates may be obtained by measuring KERMA (Kinetic Energy Released in Matter) in anthropomorphic phantoms and referencing these values to free-in-air X-ray intensity. To measure KERMA ratios (R{sub K}) in pediatric phantoms at CT. CT scans produce an air KERMA K in a phantom and an air KERMA K{sub CT} at isocenter. KERMA ratios (R{sub K}) are defined as (K/K{sub CT}), measured using TLD chips in phantoms representing newborns to 10-year-olds. R{sub K} in the newborn is approximately constant. For the other phantoms, there is a peak R{sub K} value in the neck. The median R{sub K} values for the GE scanner at 120 kV were 0.92, 0.83, 0.77 and 0.76 for newborns, 1-year-olds, 5-year-olds and 10-year-olds, respectively. Organ R{sub K} values were 0.91 {+-} 0.04, 0.84 {+-} 0.07, 0.74 {+-} 0.09 and 0.72 {+-} 0.10 in newborns, 1-year-olds, 5-year-olds and 10-year-olds, respectively. At 120 kV, a Siemens Sensation 16 scanner had R{sub K} values 5% higher than those of the GE LightSpeed Ultra. KERMA ratios may be combined with air KERMA measurements at the isocenter to estimate organ doses in pediatric CT patients. (orig.)

  14. Intercomparison of {sup 192}Ir brachytherapy source measurement in UK hospitals, 1997[Iridium; Low dose rate; LDR; Air kerma rate; AKR

    Energy Technology Data Exchange (ETDEWEB)

    Jerome, S.; Ciocanel, M.; Bass, G. [and others

    1997-11-01

    An exercise to intercompare the measurement of {sup 192}Ir brachytherapy sources has been completed and the results indicate that participants were able to measure the air kerma rate (AKR) of the sources with reasonable accuracy. However, it is noted that; (a) 60% of the results can be unequivocally accepted, 11% are rejected as being definitely discrepant; (b) there is a general low bias on the results; (c) there appears to be no particular instrument bias; (d) there needs to be a fuller consideration of measurement uncertainties by the users; (e) there was a wide range of reference data used; and, (f) calibration of the instrumentation relies in many cases, on manufacturer supplied data. It is recommended that the exercise is repeated in the near future, and that the use of thick ('hairpin') wires is included in the next exercise. (author)

  15. Determination of the Kwall correction factor for a cylindrical ionization chamber to measure air-kerma in 60Co gamma beams

    International Nuclear Information System (INIS)

    The factor Kwall to correct for photon attenuation and scatter in the wall of ionization chambers for 60Co air-kerma measurement has been traditionally determined by a procedure based on a linear extrapolation of the chamber current to zero wall thickness. Monte Carlo calculations by Rogers and Bielajew (1990 Phys. Med. Biol. 35 1065-78) provided evidence, mostly for chambers of cylindrical and spherical geometry, of appreciable deviations between the calculated values of Kwall and those obtained by the traditional extrapolation procedure. In the present work an experimental method other than the traditional extrapolation procedure was used to determine the Kwall factor. In this method the dependence of the ionization current in a cylindrical chamber was analysed as a function of an effective wall thickness in place of the physical (radial) wall thickness traditionally considered in this type of measurement. To this end the chamber wall was ideally divided into distinct regions and for each region an effective thickness to which the chamber current correlates was determined. A Monte Carlo calculation of attenuation and scatter effects in the different regions of the chamber wall was also made to compare calculation to measurement results. The Kwall values experimentally determined in this work agree within 0.2% with the Monte Carlo calculation. The agreement between these independent methods and the appreciable deviation (up to about 1%) between the results of both these methods and those obtained by the traditional extrapolation procedure support the conclusion that the two independent methods providing comparable results are correct and the traditional extrapolation procedure is likely to be wrong. The numerical results of the present study refer to a cylindrical cavity chamber like that adopted as the Italian national air-kerma standard at INMRI-ENEA (Italy). The method used in this study applies, however, to any other chamber of the same type. (author)

  16. Reference dosimetry at the Australian Synchrotron's imaging and medical beamline using free-air ionization chamber measurements and theoretical predictions of air kerma rate and half value layer

    Energy Technology Data Exchange (ETDEWEB)

    Crosbie, Jeffrey C.; Rogers, Peter A. W. [Department of Obstetrics and Gynaecology, University of Melbourne, The Royal Women' s Hospital, Parkville, Victoria 3052 (Australia); Stevenson, Andrew W. [CSIRO Materials Science and Engineering, Clayton, Victoria 3169 (Australia); Hall, Christopher J. [Imaging and Medical Beamline, Australian Synchrotron, Clayton, Victoria 3168 (Australia); Lye, Jessica E. [Australian Radiation Protection and Nuclear Safety Agency, Yallambie, Victoria 3085 (Australia); Nordstroem, Terese [KTH Royal Institute of Technology, Stockholm SE-100 44 (Sweden); Midgley, Stewart M. [School of Physics, Monash University, Clayton, Victoria 3800 (Australia); Lewis, Robert A. [Department of Medical Imaging and Radiation Sciences, Monash University, Clayton, Victoria 3800 (Australia)

    2013-06-15

    Purpose: Novel, preclinical radiotherapy modalities are being developed at synchrotrons around the world, most notably stereotactic synchrotron radiation therapy and microbeam radiotherapy at the European Synchrotron Radiation Facility in Grenoble, France. The imaging and medical beamline (IMBL) at the Australian Synchrotron has recently become available for preclinical radiotherapy and imaging research with clinical trials, a distinct possibility in the coming years. The aim of this present study was to accurately characterize the synchrotron-generated x-ray beam for the purposes of air kerma-based absolute dosimetry. Methods: The authors used a theoretical model of the energy spectrum from the wiggler source and validated this model by comparing the transmission through copper absorbers (0.1-3.0 mm) against real measurements conducted at the beamline. The authors used a low energy free air ionization chamber (LEFAC) from the Australian Radiation Protection and Nuclear Safety Agency and a commercially available free air chamber (ADC-105) for the measurements. The dimensions of these two chambers are different from one another requiring careful consideration of correction factors. Results: Measured and calculated half value layer (HVL) and air kerma rates differed by less than 3% for the LEFAC when the ion chamber readings were corrected for electron energy loss and ion recombination. The agreement between measured and predicted air kerma rates was less satisfactory for the ADC-105 chamber, however. The LEFAC and ADC measurements produced a first half value layer of 0.405 {+-} 0.015 and 0.412 {+-} 0.016 mm Cu, respectively, compared to the theoretical prediction of 0.427 {+-} 0.012 mm Cu. The theoretical model based upon a spectrum calculator derived a mean beam energy of 61.4 keV with a first half value layer of approximately 30 mm in water. Conclusions: The authors showed in this study their ability to verify the predicted air kerma rate and x-ray attenuation curve on the IMBL using a simple experimental method, namely, HVL measurements. The HVL measurements strongly supports the x-ray beam spectrum, which in turn has a profound effect on x-ray dosimetry.

  17. Poster — Thur Eve — 24: Commissioning and preliminary measurements using an Attix-style free air ionization chamber for air kerma measurements on the BioMedical Imaging and Therapy beamlines at the Canadian Light Source

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, D [Department of Oncology, University of Alberta, Edmonton, AB (Canada); McEwen, M; Shen, H [Ionizing Radiation Standards, National Research Council of Canada, Ottawa, ON (Canada); Siegbahn, EA [Department of Medical Physics, Stockholm University, Stockholm (Sweden); Fallone, BG; Warkentin, B [Department of Oncology, University of Alberta, Edmonton, AB (Canada); Department of Medical Physics, Cross Cancer Institute, Edmonton, AB (Canada)

    2014-08-15

    Synchrotron facilities, including the Canadian Light Source (CLS), provide opportunities for the development of novel imaging and therapy applications. A vital step progressing these applications toward clinical trials is the availability of accurate dosimetry. In this study, a refurbished Attix-style (cylindrical) free air chamber (FAC) is tested and used for preliminary air kerma measurements on the two BioMedical Imaging and Therapy (BMIT) beamlines at the CLS. The FAC consists of a telescoping chamber that relies on a difference measurement of collected charge in expanded and collapsed configurations. At the National Research Council's X-ray facility, a Victoreen Model 480 FAC was benchmarked against two primary standard FACs. The results indicated an absolute accuracy at the 0.5% level for energies between 60 and 150 kVp. A series of measurements were conducted on the small, non-uniform X-ray beams of the 05B1-1 (?8 – 100 keV) and 05ID-2 (?20 – 200 keV) beamlines for a variety of energies, filtrations and beam sizes. For the 05B1-1 beam with 1.1 mm of Cu filtration, recombination corrections of less than 5 % could only be achieved for field sizes no greater than 0.5 mm × 0.6 mm (corresponding to an air kerma rate of ? 57 Gy/min). Ionic recombination thus presents a significant challenge to obtaining accurate air kerma rate measurements using this FAC in these high intensity beams. Future work includes measurements using a smaller aperture to sample a smaller and thus more uniform beam area, as well as experimental and Monte Carlo-based investigation of correction factors.

  18. Poster — Thur Eve — 24: Commissioning and preliminary measurements using an Attix-style free air ionization chamber for air kerma measurements on the BioMedical Imaging and Therapy beamlines at the Canadian Light Source

    International Nuclear Information System (INIS)

    Synchrotron facilities, including the Canadian Light Source (CLS), provide opportunities for the development of novel imaging and therapy applications. A vital step progressing these applications toward clinical trials is the availability of accurate dosimetry. In this study, a refurbished Attix-style (cylindrical) free air chamber (FAC) is tested and used for preliminary air kerma measurements on the two BioMedical Imaging and Therapy (BMIT) beamlines at the CLS. The FAC consists of a telescoping chamber that relies on a difference measurement of collected charge in expanded and collapsed configurations. At the National Research Council's X-ray facility, a Victoreen Model 480 FAC was benchmarked against two primary standard FACs. The results indicated an absolute accuracy at the 0.5% level for energies between 60 and 150 kVp. A series of measurements were conducted on the small, non-uniform X-ray beams of the 05B1-1 (?8 – 100 keV) and 05ID-2 (?20 – 200 keV) beamlines for a variety of energies, filtrations and beam sizes. For the 05B1-1 beam with 1.1 mm of Cu filtration, recombination corrections of less than 5 % could only be achieved for field sizes no greater than 0.5 mm × 0.6 mm (corresponding to an air kerma rate of ? 57 Gy/min). Ionic recombination thus presents a significant challenge to obtaining accurate air kerma rate measurements using this FAC in these high intensity beams. Future work includes measurements using a smaller aperture to sample a smaller and thus more uniform beam area, as well as experimental and Monte Carlo-based investigation of correction factors

  19. Control letters and uncertainties of the kerma patterns in air, dose absorbed in water and dose absorbed in air of the LSCD

    International Nuclear Information System (INIS)

    With the purpose of characterizing the component of uncertainty of long term of the patron ionization chambers of the LSCD, for the magnitudes: speed of kerma in air ??·, dose speed absorbed in water D?·, and speed absorbed dose in air D?·, it use the technique of letters of control l-MR/S. This statistical technique it estimates the component of uncertainty of short term by means of the deviation standard inside groups ?? and that of long term by means of the standard deviation among groups ??, being this it finishes an estimator of the stability of the patterns.The letters of control l-MR/S it construct for: i) ??·, in radiation field of 60Co for patterns: primary CC01 series 131, secondary NE 2611 series 176, secondary PTW TN30031 series 578 and Third PTW W30001 series 365. ii) D?),en radiation field of 60Co for patterns: primary CC01 series 131, Secondary PTW TN30031 series 578 and tertiary PTW W30001 series 365. iii) I-MR/S with extrapolation chamber PTW primary pattern, measurement realizes in secondary patron fields of 90Sr-90Y. The expanded uncertainty U it is calculated of agreement with the Guide of the ISO/BIPM being observed the following thing: a. In some the cases ??, is the component of the U that more contributed to this. Therefore, it is necessary to settle down technical of sampling in those mensurations that allow to reduce the value of ??. For example with sizes of subgroup ?? 30 data, or with a number of subgroups ??. That which is achieved automating the mensuration processes. b.The component of the temperature is also one of those that but they contribute to the U, of there the necessity of: to recover the tracking for this magnitude of it influences and to increase the precision in the determinations of the temperature to diminish their influence in the U. c. The percentage difference of the magnitudes dosemeters carried out by it patterns are consistent with U certain. However, it is necessary to diminish the uncertainty in the physical factors different to ?? and ?? for the one case of the primary patterns; because these they should be those of smaller value of U. d. In the case of the secondary patterns and tertiary for the realization of the??· is necessary to determine the corrections explicitly for recombination and polarization; and to analyze their contribution in the U. e. It is necessary to recover the tracking for the mensurations of the humidity. f. It is recommended to continue the control mensurations for each pattern, taking its the least a measure every fifteen days, that it corresponds at two measured for month and 24 at the year. g. The operation of the air conditioned perturb the measurement for such as it recommends not to use it, and alone to leave in balance the chamber with the air of the engine room. (Author)

  20. Neutron kerma factors, and water equivalence of some tissue substitutes

    International Nuclear Information System (INIS)

    The kerma factors and kerma relative to air and water of 24 compounds used as tissue substitutes were calculated for neutron energy from 2.53 x 10-8 up to 29 MeV. The kerma ratio of the tissue substitutes relative to air and water were calculated by the ratio of kerma factors of the tissue substitute to air and water respectively. The water equivalence of the selected tissue substitutes was observed above neutron energies 100 eV. Kerma ratio relative to the air for Poly-vinylidene fluoride and Teflon are found to be nearest to unity in very low energy (up to 1 eV) and above 63 eV respectively. It was found that the natural rubber as a water equivalent tissue substitute compound. The results of the kerma factors in our investigation shows a very good agreement with those published in ICRU-44. We found that at higher neutron energies, the kerma factors and kerma ratios of the selected tissue substitute compounds are approximately same, but differences are large for energies below 100 eV. (Author)

  1. Estudo comparativo da qualidade da imagem e do kerma, de entrada e de saída, em simulador de tórax utilizando sistemas analógico e digitalizado CR de aquisição de imagens / Comparative study of image quality and entrance and exit air kerma measurements on chest phantom utilizing analog and CR digital imaging systems

    Scientific Electronic Library Online (English)

    Renata Matos da, Luz; Gabriela, Hoff.

    2010-02-01

    Full Text Available OBJETIVO: O processo de migração de sistemas analógicos para digitalizados, para aplicações diagnósticas, requer cuidados específicos, a fim de manter a qualidade das imagens e minimizar a dose no paciente. Este trabalho tem como objetivo analisar e comparar a qualidade da imagem e o kerma num simul [...] ador não antropomórfico de tórax gerados por sistemas analógicos e digitalizados CR. MATERIAIS E MÉTODOS: Foram analisados a qualidade da imagem e o kerma, de entrada e saída, no simulador para dois equipamentos de raios X diferentes (Siemens e Emic), com diferentes sistemas de retificação de onda (12 pulsos e alta frequência). Ambos os sistemas (analógico e digitalizado) estavam sendo utilizados no mesmo local. Foram geradas imagens em filme e em image plates. RESULTADOS: Foi observado aumento na tensão e/ou na carga transportada pelo tubo de raios X quando houve a migração para o sistema CR, para manutenção das características diagnósticas da imagem. Isto resultou em aumento de kerma coletado. CONCLUSÃO: As maiores diferenças determinadas (aumento de dose e redução da qualidade da imagem) foram observadas no equipamento com retificação de onda de 12 pulsos e transdutor de imagem CR (image plates). Abstract in english OBJECTIVE: The process of migration from analog to digital imaging system requires specific attention to preserve images quality and minimizing the dose to the patients. The present study was aimed at analyzing and comparing images quality and entrance and exist air kerma measurements in a non-anthr [...] opomorphic chest phantom with analog and CR digital imaging systems. MATERIALS AND METHODS: Two different X-ray units (Siemens and Emic) with different wave rectification systems (12-pulse and high-frequency) were utilized in a single institution along the process of migration from analog to CR digital imaging system. Images were acquired on films and image plates. RESULTS: An increase on the X-ray tube peak voltage and/or load was observed in the migration from analog to CR digital system to preserve the diagnostic quality of the image. As a result, an increase in the air kerma rate was observed. CONCLUSION: The greatest differences (increase in dose and decrease in image quality) were observed with the 12-pulse wave rectification system with the CR image transducer (imaging plates).

  2. Estudo comparativo da qualidade da imagem e do kerma, de entrada e de saída, em simulador de tórax utilizando sistemas analógico e digitalizado CR de aquisição de imagens Comparative study of image quality and entrance and exit air kerma measurements on chest phantom utilizing analog and CR digital imaging systems

    Directory of Open Access Journals (Sweden)

    Renata Matos da Luz

    2010-02-01

    Full Text Available OBJETIVO: O processo de migração de sistemas analógicos para digitalizados, para aplicações diagnósticas, requer cuidados específicos, a fim de manter a qualidade das imagens e minimizar a dose no paciente. Este trabalho tem como objetivo analisar e comparar a qualidade da imagem e o kerma num simulador não antropomórfico de tórax gerados por sistemas analógicos e digitalizados CR. MATERIAIS E MÉTODOS: Foram analisados a qualidade da imagem e o kerma, de entrada e saída, no simulador para dois equipamentos de raios X diferentes (Siemens e Emic, com diferentes sistemas de retificação de onda (12 pulsos e alta frequência. Ambos os sistemas (analógico e digitalizado estavam sendo utilizados no mesmo local. Foram geradas imagens em filme e em image plates. RESULTADOS: Foi observado aumento na tensão e/ou na carga transportada pelo tubo de raios X quando houve a migração para o sistema CR, para manutenção das características diagnósticas da imagem. Isto resultou em aumento de kerma coletado. CONCLUSÃO: As maiores diferenças determinadas (aumento de dose e redução da qualidade da imagem foram observadas no equipamento com retificação de onda de 12 pulsos e transdutor de imagem CR (image plates.OBJECTIVE: The process of migration from analog to digital imaging system requires specific attention to preserve images quality and minimizing the dose to the patients. The present study was aimed at analyzing and comparing images quality and entrance and exist air kerma measurements in a non-anthropomorphic chest phantom with analog and CR digital imaging systems. MATERIALS AND METHODS: Two different X-ray units (Siemens and Emic with different wave rectification systems (12-pulse and high-frequency were utilized in a single institution along the process of migration from analog to CR digital imaging system. Images were acquired on films and image plates. RESULTS: An increase on the X-ray tube peak voltage and/or load was observed in the migration from analog to CR digital system to preserve the diagnostic quality of the image. As a result, an increase in the air kerma rate was observed. CONCLUSION: The greatest differences (increase in dose and decrease in image quality were observed with the 12-pulse wave rectification system with the CR image transducer (imaging plates.

  3. Air kerma to personal dose equivalent conversion factors for ICRU and ISO recommended slab phantoms for photons from 20 keV to 1 MeV

    International Nuclear Information System (INIS)

    The present report summarizes the studies carried out at ENEA-AMB-PRO-IRP (Institute for Radiation Protection) that were addressed to the determination of air kerma to personal dose equivalent conversion coefficients for two practical phantoms as proposed by ICRU (International Commission for Radiation Units and Measurements) and by ISO (International Standard Organization) for photon personal dosimeters' calibration procedure. The analyses, developed using the MCNP Monte Carlo code, were mainly aimed at establishing which of the two proposed phantoms better approximates the ICRU theoretical one. Furthermore a complete tabulation of the conversion coefficients is supplied for monoenergetic photon beams from 20 keV to 1 MeV as well as for the two ISO X-ray reference series Wide Spectrum and Narrow Spectrum. The study has been performed in the framework of the CEC Contract F13P-CT92-0064 'The Measurement of the Spectral and Angular Distribution of External Radiations in Workplace and Implications for Personal Dosimetry

  4. Implementation of the method air-kerma product area in KAP camera calibration with reference qualities of X-ray series at the SSDL RQR of Mexico

    International Nuclear Information System (INIS)

    The X-Ray machines, at a reference laboratory for the instrument calibration in diagnostic radiology, should compliance with the ISO requirements. Sometimes there is not available as much laboratories as needed in Latin American countries. So this project shows the KAP ionization chamber implementation method using the TRS-457 radiation quality from the IAEA at the SSDL of Mexico. The KAP instruments calibration method consists in doing a substitution comparison using a standard reference with traceability to a primary laboratory and a transmission-monitoring chamber that measures the number of photons of the X-ray primary beam. A KAP chamber calibration requires a special array that consists in collocating the chamber in two different positions of its calibration process. Then, with air kerma-area product coefficient together with a corrected electrometer measure at referential conditions, the patient dosimetry magnitudes are calculated. The dosimetry necessity at hospitals always will be in function of possessing a highly reliable calibration coefficient chamber for making these measures. That dosimetry results will help in reducing the total or partial irradiation emitted to the human body of the patient. This is how stochastic risks will be lessened due to diagnostic studies. The purpose of this project is to have a synergy with calibration for making known that the SSDL of Mexico has the technical capacity to act as a link between primary standard dosimetry laboratories and the ionizing radiation equipment users who require that their KAP chamber have traceability from the primary standard to the user. (author)

  5. Comparison between absorbed dose to water standards established by water calorimetry at the LNE-LNHB and by application of international air-kerma based protocols for kilovoltage medium energy x-rays

    International Nuclear Information System (INIS)

    Nowadays, the absorbed dose to water for kilovoltage x-ray beams is determined from standards in terms of air-kerma by application of international dosimetry protocols. New standards in terms of absorbed dose to water has just been established for these beams at the LNE-LNHB, using water calorimetry, at a depth of 2 cm in water in accordance with protocols. The aim of this study is to compare these new standards in terms of absorbed dose to water, to the dose values calculated from the application of four international protocols based on air-kerma standards (IAEA TRS-277, AAPM TG-61, IPEMB and NCS-10). The acceleration potentials of the six beams studied are between 80 and 300 kV with half-value layers between 3.01 mm of aluminum and 3.40 mm of copper. A difference between the two methods smaller than 2.1% was reported. The standard uncertainty of water calorimetry being below 0.8%, and the one associated with the values from protocols being around 2.5%, the results are in good agreement. The calibration coefficients of some ionization chambers in terms of absorbed dose to water, established by application of calorimetry and air-kerma based dosimetry protocols, were also compared. The best agreement with the calibration coefficients established by water calorimetry was found for those established with the AAPM TG-61 protocol. (paper)

  6. Microionization chamber air-kerma calibration coefficients as a function of photon energy for x-ray spectra in the range of 20-250 kVp relative to {sup 60}Co

    Energy Technology Data Exchange (ETDEWEB)

    Snow, J. R.; Micka, J. A.; DeWerd, L. A. [Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin 53705 (United States)

    2013-04-15

    Purpose: To investigate the applicability of a wide range of microionization chambers for reference dosimetry measurements in low- and medium-energy x-ray beams. Methods: Measurements were performed with six cylindrical microchamber models, as well as one scanning chamber and two Farmer-type chambers for comparison purposes. Air-kerma calibration coefficients were determined at the University of Wisconsin Accredited Dosimetry Calibration Laboratory for each chamber for a range of low- and medium-energy x-ray beams (20-250 kVp), with effective energies ranging from 11.5 keV to 145 keV, and a {sup 60}Co beam. A low-Z proof-of-concept microchamber was developed and calibrated with and without a high-Z silver epoxy on the collecting electrode. Results: All chambers composed of low-Z materials (Z{<=} 13), including the Farmer-type chambers, the scanning chamber, and the PTW TN31014 and the proof-of-concept microchambers, exhibited air-kerma calibration coefficients with little dependence on the quality of the beam. These chambers typically exhibited variations in calibration coefficients of less than 3% with the beam quality, for medium energy beams. However, variations in air-kerma calibration coefficients of greater than 50% were measured over the range of medium-energy x-ray beams for each of the microchambers containing high-Z collecting electrodes (Z > 13). For these high-Z chambers, which include the Exradin A14SL and A16 chambers, the PTW TN31006 chamber, the IBA CC01 chamber, and the proof-of-concept chamber containing silver, the average variation in air-kerma calibration coefficients between any two calibration beams was nearly 25% over the entire range of beam qualities investigated. Conclusions: Due to the strong energy dependence observed with microchambers containing high-Z components, these chambers may not be suitable dosimeters for kilovoltage x-ray applications, as they do not meet the TG-61 requirements. It is recommended that only microchambers containing low-Z materials (Z{<=} 13) be considered for air-kerma calibrations for reference dosimetry in low- and medium-energy x-ray beams.

  7. Microionization chamber air-kerma calibration coefficients as a function of photon energy for x-ray spectra in the range of 20–250 kVp relative to 60Co

    International Nuclear Information System (INIS)

    Purpose: To investigate the applicability of a wide range of microionization chambers for reference dosimetry measurements in low- and medium-energy x-ray beams. Methods: Measurements were performed with six cylindrical microchamber models, as well as one scanning chamber and two Farmer-type chambers for comparison purposes. Air-kerma calibration coefficients were determined at the University of Wisconsin Accredited Dosimetry Calibration Laboratory for each chamber for a range of low- and medium-energy x-ray beams (20–250 kVp), with effective energies ranging from 11.5 keV to 145 keV, and a 60Co beam. A low-Z proof-of-concept microchamber was developed and calibrated with and without a high-Z silver epoxy on the collecting electrode. Results: All chambers composed of low-Z materials (Z? 13), including the Farmer-type chambers, the scanning chamber, and the PTW TN31014 and the proof-of-concept microchambers, exhibited air-kerma calibration coefficients with little dependence on the quality of the beam. These chambers typically exhibited variations in calibration coefficients of less than 3% with the beam quality, for medium energy beams. However, variations in air-kerma calibration coefficients of greater than 50% were measured over the range of medium-energy x-ray beams for each of the microchambers containing high-Z collecting electrodes (Z > 13). For these high-Z chambers, which include the Exradin A14SL and A16 chambers, the PTW TN31006 chamber, the IBA CC01 chamber, and the proof-of-concept chamber containing silver, the average variation in air-kerma calibration coefficients between any two calibration beams was nearly 25% over the entire range of beam qualities investigated. Conclusions: Due to the strong energy dependence observed with microchambers containing high-Z components, these chambers may not be suitable dosimeters for kilovoltage x-ray applications, as they do not meet the TG-61 requirements. It is recommended that only microchambers containing low-Z materials (Z? 13) be considered for air-kerma calibrations for reference dosimetry in low- and medium-energy x-ray beams.

  8. The calculation of wall and non-uniformity correction factors for the BIPM air-kerma standard for 60Co using the Monte Carlo code PENELOPE

    International Nuclear Information System (INIS)

    Traditionally, the correction factor kwall for attenuation and scatter in the walls of cavity ionization chamber primary standards has been evaluated experimentally using an extrapolation method. During the past decade, there have been a number of Monte Carlo calculations of kwall indicating that for certain ionization chamber types the extrapolation method may not be valid. In particular, values for kwall have been proposed that, if adopted by each laboratory concerned, would have a significant effect on the results of international comparisons of air-kerma primary standards. The calculations have also proposed new values for the axial component kan of the point-source uniformity correction. Central to the results of international comparisons is the BIPM air-kerma standard. Unlike most others, the BIPM standard is of the parallel-plate design for which the extrapolation method for evaluating kwall should be valid. The value in use at present is kwall=1.0026 (standard uncertainty 0.0008). Rogers and Treurniet calculated the value kwall=1.0014 for the BIPM standard, which is in moderate agreement with the value in use (no overall uncertainty was given). However, they also calculated kan=1.0024 (statistical uncertainty 0.0003) which is very different from the value kan=0.9964 (0.0007) in use at present for the BIPM standard. A new 60Co facility has recently been installed at the BIPM and the opportunity was taken to re-evaluate the correction factors for the BIPM standard in this new beam. Given that almost all of the Monte Carlo work to date has used the EGS Monte Carlo code, it was decided to use the code PENELOPE. The new source, container, head and collimating jaws were simulated in detail with more that fifty components being modelled, as shown. This model was used to create a phase-space file in the plane 90 cm from the source. The normalized distribution of photon number with energy is shown, where the various sources of scattered photons are identified. This phase-space file was used to calculate kwall for the BIPM standard using the technique of photon regeneration. At the point of each photon interaction in the chamber wall, a new photon is generated with the same energy and direction as the incoming photon. The deposition of energy in the air cavity by regenerated photons effectively corrects for attenuation in the wall. At the same time, any outgoing scattered photon is tagged so that a correction for the energy deposition due to scattered photons may be evaluated. The result of these calculations is kwall=1.0017 (statistical uncertainty 0.0001), which is in good agreement with previous results. The overall uncertainties remain to be evaluated. For the calculation of kan, a modified technique was used which makes use of the full phase-space information rather than assuming, as is usual, that the beam is well approximated by a point source. When using the same model for the BIPM standard as used previously, the result kan=1.0032 (statistical uncertainty 0.0005) agrees reasonably well with previous results (the small difference may be due to the use of a point source rather than the realistic angular distribution). However, there is evidence that these new values are an artefact of the method and model and that the true non-uniformity correction is much closer to unity. Before implementing any new kan value for the BIPM standard, a more detailed study will be undertaken to explain the large difference between the new and existing values

  9. Ferramenta computacional para avaliação de kerma no ar em aplicações de radioproteção em áreas de internação de pacientes: proposição de um método simples para avaliação experimental / Computational toolkit for evaluating air kerma with the purpose of radiation protection of hospital inpatients: proposal of a simple experimental evaluation method

    Scientific Electronic Library Online (English)

    Gabriela, Hoff; José Rodrigo Mendes, Andrade; Andréia Caroline Fischer da Silveira, Fischer; Alexandre, Bacelar.

    2012-04-01

    Full Text Available OBJETIVO: Apresentar uma ferramenta de análise de dados que pode ser utilizada para proteção de pacientes e trabalhadores em áreas de uso de equipamentos móveis. MATERIAIS E MÉTODOS: Foi desenvolvida uma ferramenta, em planilha ativa Excel®, que utiliza medidas de exposição para gerar um banco de da [...] dos de fatores de forma e calcular o kerma no ar ao entorno de um leito. O banco de dados inicial foi coletado com três equipamentos móveis. Um espalhador não antropomórfico foi utilizado, sendo realizadas medidas de exposição em uma malha de (4,2 × 4,2) m², ao passo de 0,3 m. RESULTADOS: A ferramenta calcula o kerma no ar (associado à exposição de pacientes expostos e ao equivalente de dose ambiente) à radiação secundária. Para distâncias inferiores a 60,0 cm, valores acima do limite máximo de equivalente de dose ambiente definido para área livre (0,5 mSv/ano) foram verificados. Os dados coletados a 2,1 m foram sempre inferiores a 12% do referido limite. CONCLUSÃO: A ferramenta é capaz de auxiliar na proteção radiológica de pacientes e trabalhadores, quando associada à coleta de dados adequada, pois possibilita a determinação de áreas livres ao entorno de leitos em áreas onde equipamentos móveis geradores de radiação X são utilizados. Abstract in english OBJECTIVE: To present a data analysis toolkit that may be utilized with the purpose of radiation protection of hospital inpatients and workers in areas where mobile apparatuses are used. MATERIALS AND METHODS: An Excel® ActiveSheet was utilized to develop a computational toolkit with exposure measur [...] ements to generate a database of shape factors and to calculate the air kerma around hospital beds. The initial database included data collected with three mobile apparatuses. A non-anthropomorphic phantom was utilized and exposure measurements were performed on a (4.2 × 4.2) m² mesh-grid at 0.3 m steps. RESULTS: The toolkit calculates the air kerma (associated with patients' radiation exposure and with ambient equivalent dose) under secondary radiation. For distances lower than 60.0 cm, values above the maximum ambient equivalent dose threshold defined for radiation free areas (0.5 mSv/year) were verified. Data collected at 2.1 m have always presented values lower than 12% of that threshold. CONCLUSION: The toolkit can aid in the radiological protection of patients and workers, provided it is combined with appropriate data collection, since it allows the determination of radiation free areas around beds in rooms where mobile X-ray apparatuses are utilized.

  10. Control letters and uncertainties of the kerma patterns in air, dose absorbed in water and dose absorbed in air of the LSCD; Cartas de control e incertidumbres de los patrones de kerma en aire, dosis absorbida en agua y dosis absorbida en aire del LSCD

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez R, M.T.; Tovar M, V.M.; Cejudo A, J. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2005-12-15

    With the purpose of characterizing the component of uncertainty of long term of the patron ionization chambers of the LSCD, for the magnitudes: speed of kerma in air {kappa}{sub {alpha}}{sub {center_dot}}, dose speed absorbed in water D{alpha}{sub {center_dot}}, and speed absorbed dose in air D{alpha}{sub {center_dot}}, it use the technique of letters of control l-MR/S. This statistical technique it estimates the component of uncertainty of short term by means of the deviation standard inside groups {sigma}{sub {omega}} and that of long term by means of the standard deviation among groups {sigma}{sub {beta}}, being this it finishes an estimator of the stability of the patterns.The letters of control l-MR/S it construct for: i) {kappa}{sub {alpha}}{sub {center_dot}}, in radiation field of {sup 60}Co for patterns: primary CC01 series 131, secondary NE 2611 series 176, secondary PTW TN30031 series 578 and Third PTW W30001 series 365. ii) D{alpha}),en radiation field of {sup 60}Co for patterns: primary CC01 series 131, Secondary PTW TN30031 series 578 and tertiary PTW W30001 series 365. iii) I-MR/S with extrapolation chamber PTW primary pattern, measurement realizes in secondary patron fields of {sup 90}Sr-{sup 90}Y. The expanded uncertainty U it is calculated of agreement with the Guide of the ISO/BIPM being observed the following thing: a. In some the cases {sigma}{sub {beta}}, is the component of the U that more contributed to this. Therefore, it is necessary to settle down technical of sampling in those mensurations that allow to reduce the value of {sigma}{sub {beta}}. For example with sizes of subgroup {eta}{sub {approx}} 30 data, or with a number of subgroups {kappa}{sub {>=}}. That which is achieved automating the mensuration processes. b.The component of the temperature is also one of those that but they contribute to the U, of there the necessity of: to recover the tracking for this magnitude of it influences and to increase the precision in the determinations of the temperature to diminish their influence in the U. c. The percentage difference of the magnitudes dosemeters carried out by it patterns are consistent with U certain. However, it is necessary to diminish the uncertainty in the physical factors different to {kappa}{sub {tau}} and {sigma}{sub {beta}} for the one case of the primary patterns; because these they should be those of smaller value of U. d. In the case of the secondary patterns and tertiary for the realization of the{kappa}{sub {alpha}}{sub {center_dot}} is necessary to determine the corrections explicitly for recombination and polarization; and to analyze their contribution in the U. e. It is necessary to recover the tracking for the mensurations of the humidity. f. It is recommended to continue the control mensurations for each pattern, taking it{sup s} the least a measure every fifteen days, that it corresponds at two measured for month and 24 at the year. g. The operation of the air conditioned perturb the measurement for such as it recommends not to use it, and alone to leave in balance the chamber with the air of the engine room. (Author)

  11. SOILRAD. A computer program to calculate air kerma, ambient dose rate and effective dose rate due to photons emitted by radionuclides distributed in soil on the soil-air surface

    International Nuclear Information System (INIS)

    In several research projects on environmental radiation there is a need for an automated system to calculate, for instance, the kerma in air or ambient dose rate that results from photons emitted by radionuclides in soil or on the soil surface. Some applications are migration of fallout radionuclides in soil, calculation of the shielding effect of soil due to landfill and the calculation of dose rate due to the naturally occurring radionuclides in soil. In the framework of an investigation aimed at determining the natural radiation background using the National Radioactivity Monitoring network (NRM), a computer application was developed for this purpose. In this report the underlying calculation method is described. An already existing method was adapted and expanded. Besides a description of this method, the structure of the SOILRAD program is illustrated and instructions for use are given. Comparison of the first results to data published elsewhere confirms the usefulness of the program. 13 figs., 4 tabs., 20 refs., 3 appendices

  12. Kinematic kerma factors

    International Nuclear Information System (INIS)

    The HEATR module of NJOY computes heat production by energy-balance (usually); that is, it assumes that the energy available for charged-particle emission and nuclear recoil can be obtained from the available energy (E + Q) minus the energy carried away by neutrons (E/sub n/) and the energy carried away by photons (anti E/sub ?/). If there are errors in either anti E/sub n/ or anti E /sub ?/, the local heating will be incorrect. In a large enough system, this heating error will be exactly compensated for by photon energy deposition, and the correct result for total heating will be obtained. However, in very small systems where most of the photons escape, the local heating can have very large errors resulting from a lack of energy conservation in the nuclear data evaluation. Accurate values for this local heating can be computed for some reactions by kinematics (radiative capture, elastic and inelastic neutron scattering). Reactions that emit charged particles are more difficult because the ENDF/B files do not contain the required particle spectra or angular distributions. Nevertheless, it is possible to establish an upper limit for the kinematic kerma factor by assuming that such reactions emit no photons. The HEATR module has been modified to add kinematic kerma factors computed in this way to the NJOY calculational path. This means that they are available for either multigroup or Monte Carlo processing

  13. Key comparison BIPM.RI(I)-K2 of the air-kerma standards of the ENEA-INMRI, Italy and the BIPM in low-energy x-rays

    International Nuclear Information System (INIS)

    A key comparison has been made between the air-kerma standards of the ENEA-INMRI, Italy and the BIPM in the low-energy x-ray range. The results show the standards to be in agreement at the level of the standard uncertainty for the comparison of 1.9 parts in 103. No significant trend with radiation quality is observed. The results are analysed and presented in terms of degrees of equivalence, suitable for entry in the BIPM key comparison database. (authors)

  14. Final report on APMP.RI(I)-K1: APMP/TCRI key comparison report of measurement of air kerma for 60Co gamma-rays

    Science.gov (United States)

    Chun, K. J.; Butler, D. J.; Webb, D.; Mahant, A. K.; Meghzifene, A.; Lee, J. H.; Hah, S. H.; Kadni, T. B.; Zhang, Y.; Kurosawa, T.; Msimang, Z. L. M.; Caseria, E. S.

    2013-01-01

    The APMP.RI(I)-K1 key comparison of the measurement standards of air kerma for 60Co gamma-rays was undertaken by the APMP/TCRI Dosimetry Working Group between 2004 and 2006, coordinated by the Korean Research Institute of Standards and Science (KRISS). In total, 10 institutes took part in the comparison, among which 7 were APMP member laboratories. Three Farmer-type commercial cavity chambers were used as transfer chambers and circulated among the participants. All the participants carried out their measurements according to the guidelines for the comparison established by the KRISS with the cooperation of the ARPANSA. For each transfer chamber, an NMI calibration coefficient was obtained and a ratio derived by dividing by the average result from the linking laboratories, ARPANSA and NMIJ. The APMP comparison reference value for each chamber was calculated as the mean of the NMI-determined calibration coefficients divided by the average result from the linking laboratories. The results showed that the maximum difference between the APMP linked ratio of a participating NMI and the APMP reference value was 1.76%. The measured ratios of the calibration coefficient RNMI, BIPM between the participating NMI and the BIPM via the link laboratories for the transfer chambers were obtained. The maximum expanded uncertainty of RNMI, BIPM for any participating laboratory was 2.0%. The degree of equivalence of each participating laboratory with respect to the key comparison reference value was also evaluated. The expanded uncertainty of the difference between the results ranged from 0.5% to 1.2%. The pair-wise degree of equivalence between each pair of laboratories was also obtained and the largest difference of the expanded uncertainty of the difference for any pair-wise degree of equivalence was within the expanded uncertainty of the measurement for the pair of laboratories. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  15. Implementation of the method air-kerma product area in KAP camera calibration with reference qualities of X-ray series at the SSDL RQR of Mexico; Implementacion del metodo producto kerma en aire-area en la calibracion de camaras KAP con calidades de referencia de rayos X de la serie RQR en el LSCD de Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Cejudo, Jesus; Tovar, Victor M., E-mail: jesus.cejudo@ini.gob.mx, E-mail: victor.tovar@inin.gob.mx [lnstituto Nacional de lnvestigaciones Nucleares (DMRI/LSDC/lNlN), Ocoyoacac (Mexico). Centro Nuclear Dr. Nabor Carrillo Flores. Laboratorio Secundario de Calibracion Dosimetrica

    2013-10-01

    The X-Ray machines, at a reference laboratory for the instrument calibration in diagnostic radiology, should compliance with the ISO requirements. Sometimes there is not available as much laboratories as needed in Latin American countries. So this project shows the KAP ionization chamber implementation method using the TRS-457 radiation quality from the IAEA at the SSDL of Mexico. The KAP instruments calibration method consists in doing a substitution comparison using a standard reference with traceability to a primary laboratory and a transmission-monitoring chamber that measures the number of photons of the X-ray primary beam. A KAP chamber calibration requires a special array that consists in collocating the chamber in two different positions of its calibration process. Then, with air kerma-area product coefficient together with a corrected electrometer measure at referential conditions, the patient dosimetry magnitudes are calculated. The dosimetry necessity at hospitals always will be in function of possessing a highly reliable calibration coefficient chamber for making these measures. That dosimetry results will help in reducing the total or partial irradiation emitted to the human body of the patient. This is how stochastic risks will be lessened due to diagnostic studies. The purpose of this project is to have a synergy with calibration for making known that the SSDL of Mexico has the technical capacity to act as a link between primary standard dosimetry laboratories and the ionizing radiation equipment users who require that their KAP chamber have traceability from the primary standard to the user. (author)

  16. Measurement of conversion coefficients between air Kerma and personal dose equivalent and backscatter factors for diagnostic X-ray beams; Determinacao experimental dos coeficientes de conversao de Kerma no ar para o equivalente de dose pessoal, Hp(d), e fatores de retroespalhamento em feixes de raios-x diagnostico

    Energy Technology Data Exchange (ETDEWEB)

    Rosado, Paulo Henrique Goncalves

    2008-07-01

    Two sets of quantities are import in radiological protection: the protection and operational quantities. Both sets can be related to basic physical quantities such as kerma through conversion coefficients. For diagnostic x-ray beams the conversion coefficients and backscatter factors have not been determined yet, those parameters are need for calibrating dosimeters that will be used to determine the personal dose equivalent or the entrance skin dose. Conversion coefficients between air kerma and personal dose equivalent and backscatter factors were experimentally determined for the diagnostic x-ray qualities RQR and RQA recommended by the International Electrotechnical Commission (IEC). The air kerma in the phantom and the mean energy of the spectrum were measured for such purpose. Harshaw LiF-100H thermoluminescent dosemeters (TLD) were used for measurements after being calibrated against an 180 cm{sup 3} Radcal Corporation ionization chamber traceable to a reference laboratory. A 300 mm x 300 mm x 150 mm polymethylmethacrylate (PMMA) slab phantom was used for deep-dose measurements. Tl dosemeters were placed in the central axis of the x-ray beam at 5, 10, 15, 25 and 35 mm depth in the phantom upstream the beam direction Another required parameter for determining the conversion coefficients from was the mean energy of the x-ray spectrum. The spectroscopy of x-ray beams was done with a CdTe semiconductor detector that was calibrated with {sup 133} Ba, {sup 241} Am and {sup 57} Co radiation sources. Measurements of the x-ray spectra were carried out for all RQR and RQA IEC qualities. Corrections due to the detector intrinsic efficiency, total energy absorption, escape fraction of the characteristic x-rays, Compton effect and attenuation in the detector were done aiming an the accurate determination of the mean energy. Measured x-ray spectra were corrected with the stripping method by using these response functions. The typical combined standard uncertainties of conversion coefficients and backscatter factors were 12% and 6% respectively. (author)

  17. Air quality complex index estimation of air pollution situations

    International Nuclear Information System (INIS)

    To improve the regional system for assessment and management of the ambient air quality in the North-East Estonian region of oil shale mining and processing, as well as natural areas, the corresponding Air Quality Complex Index (AQI) has been elaborated. This method enables to generalize a large number of measured numerical values of concentrations of pollutants in case of multicomponential pollution fields and makes the results more easily understandable. The AQI is suitable for the real-time monitoring as well as for prediction of air quality values and pollution situations by calculated data. (author)

  18. CDC WONDER: Daily Air Temperatures and Heat Index

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Daily Air Temperature and Heat Index data available on CDC WONDER are county-level daily average air temperatures and heat index measures spanning the years...

  19. SOIL{sub R}AD. A computer program to calculate air kerma, ambient dose rate and effective dose rate due to photons emitted by radionuclides distributed in soil on the soil-air surface

    Energy Technology Data Exchange (ETDEWEB)

    Blaauboer, R.O.

    1995-07-01

    In several research projects on environmental radiation there is a need for an automated system to calculate, for instance, the kerma in air or ambient dose rate that results from photons emitted by radionuclides in soil or on the soil surface. Some applications are migration of fallout radionuclides in soil, calculation of the shielding effect of soil due to landfill and the calculation of dose rate due to the naturally occurring radionuclides in soil. In the framework of an investigation aimed at determining the natural radiation background using the National Radioactivity Monitoring network (NRM), a computer application was developed for this purpose. In this report the underlying calculation method is described. An already existing method was adapted and expanded. Besides a description of this method, the structure of the SOIL{sub R}AD program is illustrated and instructions for use are given. Comparison of the first results to data published elsewhere confirms the usefulness of the program. 13 figs., 4 tabs., 20 refs., 3 appendices.

  20. Key Comparison APMP.RI(I)-K2 of air kerma standards for the CCRI reference radiation qualities for low-energy x-rays, including a supplementary comparison for the ISO 4037 narrow spectrum series

    International Nuclear Information System (INIS)

    An indirect comparison was performed between nine national standards for air kerma for the CCRI radiation qualities from 10 kV to 50 kV (APMP.RI(I)-K2) and for the ISO 4037 narrow spectrum series (15 kV and 40 kV). Among the nine institutes that participated in the comparison, seven institutes were APMP member laboratories. Three commercially available thin window parallel plate ionization chambers were used as transfer instruments and circulated among the participants. The pilot laboratory, the NMIJ/AIST, served also as the link to the corresponding BIPM.RI(I)-K2 comparison. The results show general agreement within the combined uncertainties, although certain results for Nuclear Malaysia, the BARC and the OAP show larger differences. (authors)

  1. Neutron KERMA factors of Human Tissues

    OpenAIRE

    Martin-Martin, A.; J.L. Gutierrez-Villanueva; Barquero, R.; Manzanares-Acuña, E.; H. R. Vega-Carrillo

    2007-01-01

    A program to calculate the neutron KERMA in human tissues has been developed. The program was developed in Mathcad and contains the neutron kerma factors of those elements that are present in different human tissues. Having the elemental composition of any human tissue the neutron kerma can be easily calculated. The program was tested using the elemental composition of tumor tissues such as sarcoma, melanoma, carcinoma and adenoid cystic. Neutron kerma for adipose and muscle tissue for normal...

  2. Calculation of neutron kerma in tissues

    International Nuclear Information System (INIS)

    Neutron kerma of normal and tumor tissues has been calculated using the tissues elemental concentration. A program developed in Math cad contains the kerma factors of C, H, O, N, Na, Mg, P, S, Cl, K, etc. that are in normal and tumor human tissues. Having the elemental composition of any human tissue the neutron kerma can be calculated. The program was tested using the elemental composition of tumor tissues such as sarcoma, melanoma, carcinoma and adenoid cystic, also neutron kerma for adipose and muscle tissue for normal adult was calculated. The results are in agreement with those published in literature. The neutron kerma for water was also calculated because in some dosimetric calculations water is used to describe normal and tumor tissues. From this comparison was found that at larger energies kerma factors are approximately the same, but energies less than 100 eV the differences are large. (Author)

  3. A new method for calculation of an air quality index

    Energy Technology Data Exchange (ETDEWEB)

    Ilvessalo, P. [Finnish Meteorological Inst., Helsinki (Finland). Air Quality Dept.

    1995-12-31

    Air quality measurement programs in Finnish towns have expanded during the last few years. As a result of this it is more and more difficult to make use of all the measured concentration data. Citizens of Finnish towns are nowadays taking more of an interest in the air quality of their surroundings. The need to describe air quality in a simplified form has increased. Air quality indices permit the presentation of air quality data in such a way that prevailing conditions are more easily understandable than when using concentration data as such. Using an air quality index always means that some of the information about concentrations of contaminants in the air will be lost. How much information is possible to extract from a single index number depends on the calculation method. A new method for the calculation of an air quality index has been developed. This index always indicates the overstepping of an air quality guideline level. The calculation of this air quality index is performed using the concentrations of all the contaminants measured. The index gives information both about the prevailing air quality and also the short-term trend. It can also warn about the expected exceeding of guidelines due to one or several contaminants. The new index is especially suitable for the real-time monitoring and notification of air quality values. The behaviour of the index was studied using material from a measurement period in the spring of 1994 in Kaepylae, Helsinki. Material from a pre-operational period in the town of Oulu was also available. (author)

  4. Comparison of air kerma-length product measurements between the PTB and the IAEA for x-radiation qualities used in computed tomography (EURAMET.RI(I)-S12, EURAMET project #1327)

    Science.gov (United States)

    Csete, István; Büermann, Ludwig; Alikhani, Babak; Gomola, Igor

    2015-01-01

    A comparison of air kerma-length product determinations for standard radiation qualities defined for use in computed tomography was performed between the PTB and the IAEA as EURAMET project #1327, registered in the KCDB as the EURAMET.RI(I)-S12 comparison. A pencil type reference-class ionization chamber of the IAEA and the three RQT beam qualities established according to the IEC standard 61627:2005 were selected for the comparison. The calibration coefficients for the transfer chamber in terms of Gycm/C at the PTB and the IAEA using the partial irradiation method recommended in the IAEA TRS 457 were determined. The results show the calibration coefficients of both laboratories were in a very good agreement of about 0.2 % well within the estimated relative standard uncertainty of the comparison of about 0.8 %. Residual correction due to the additional aperture required for partial irradiation of pencil chambers and feasibility of the full irradiation method were also studied. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  5. Comparison of air kerma-length product measurements between the PTB and the IAEA for x-radiation qualities used in computed tomography (EURAMET.RI(I)-S12, EURAMET project 1327)

    International Nuclear Information System (INIS)

    A comparison of air kerma-length product determinations for standard radiation qualities defined for use in computed tomography (CT) was performed between the PTB and the IAEA as EURAMET project 1327, registered in the KCDB as the EURAMET.RI(I)-S12 comparison. A pencil type reference-class ionization chamber of the IAEA and the three RQT beam qualities established according to the IEC standard 61627:2005 were selected for the comparison. The calibration coefficients for the transfer chamber in terms of Gy cm/C at the PTB and the IAEA using the partial irradiation method recommended in the IAEA TRS 457 were determined. The results show the calibration coefficients of both laboratories were in a very good agreement of about 0.2 % well within the estimated relative standard uncertainty of the comparison of about 0.8 %. Residual correction due to the additional aperture required for partial irradiation of pencil chambers and feasibility of the full irradiation method were also studied. (authors)

  6. KERMA received in neck by woman subject to mammography survey

    International Nuclear Information System (INIS)

    This paper provides information about the Air KERMA received in the neck by women subjected to mammography surveys. In this investigation we demonstrated that the protection given in mammography units is insufficient because the neck protector is only made up of plastic, in consequence the neck receives unnecessary doses. We used for the radiological survey an Electrometer RADCAL, model: 9060, serial 99-1724 and an Ionization Chamber 180 cc. RADCAL, model: 10X5-60, serial: 18304.We carried out 15 Quality Control inspections in different mammography units used for screening breast cancer from different manufacturers and these QC inspections included radiological surveys. These inspections were made in a two year period. The ionization chamber was placed around the thyroid protector (left, front and right) and the Air KERMA was measured under clinical condition. We found inadequate protection in the thyroid protector. The Air KERMA around the thyroid protector was between 40 and 80 mGy/min. This investigation demonstrates that is impossible to postpone the need to demand mammography manufacturer to modify and reinforce the thyroid protector, and we urge all International Radiological Protection Association to take steps to insure the well being of our patients and to pursuit manufacturers to meet security standards required in order to reduce the exposure of the patient's neck. (author)

  7. In-patient to isocenter KERMA ratios in CT

    Energy Technology Data Exchange (ETDEWEB)

    Huda, Walter; Ogden, Kent M.; Lavallee, Robert L.; Roskopf, Marsha L.; Scalzetti, Ernest M. [Department of Radiology and Radiological Science, Medical University of South Carolina (MUSC), 96 Jonathan Lucas Street (MSC 323), Charleston, South Carolina 29425-3230 (United States); Department of Radiology, SUNY Upstate Medical University, 750 E Adams Street, Syracuse, New York 13210 (United States)

    2011-10-15

    Purpose: To estimate in-patient KERMA for specific organs in computed tomography (CT) scanning using ratios to isocenter free-in-air KERMA obtained using a Rando phantom.Method: A CT scan of an anthropomorphic phantom results in an air KERMA K at a selected phantom location and air kerma K{sub CT} at the CT scanner isocenter when the scan is repeated in the absence of the phantom. The authors define the KERMA ratio (R{sub K}) as K/ K{sub CT}, which were experimentally determined in a Male Rando Phantom using lithium fluoride chips (TLD-100). R{sub K} values were obtained for a total of 400 individual point locations, as well as for 25 individual organs of interest in CT dosimetry. CT examinations of Rando were performed on a GE LightSpeed Ultra scanner operated at 80 kV, 120 kV, and 140 kV, as well as a Siemens Sensation 16 operated at 120 kV. Results: At 120 kV, median R{sub K} values for the GE and Siemens scanners were 0.60 and 0.64, respectively. The 10th percentile R{sub K} values ranged from 0.34 at 80 kV to 0.54 at 140 kV, and the 90th percentile R{sub K} values ranged from 0.64 at 80 kV to 0.78 at 140 kV. The average R{sub K} for the 25 Rando organs at 120 kV was 0.61 {+-} 0.08. Average R{sub K} values in the head, chest, and abdomen showed little variation. Relative to R{sub K} values in the head, chest, and abdomen obtained at 120 kV, R{sub K} values were about 12% lower in the pelvis and about 58% higher in the cervical spine region. Average R{sub K} values were about 6% higher on the Siemens Sensation 16 scanner than the GE LightSpeed Ultra. Reducing the x-ray tube voltage from 120 kV to 80 kV resulted in an average reduction in R{sub K} value of 34%, whereas increasing the x-ray tube voltage to 140 kV increased the average R{sub K} value by 9%. Conclusions: In-patient to isocenter relative KERMA values in Rando phantom can be used to estimate organ doses in similar sized adults undergoing CT examinations from easily measured air KERMA values at the isocenter (free in air). Conversion from in-patient air KERMA values to tissue dose would require the use of energy-appropriate conversion factors.

  8. Comparison of the air-kerma standards of the ENEA-INMRI and the BIPM in the medium-energy X-ray range

    International Nuclear Information System (INIS)

    An indirect comparison has been made between the air erma standards of the ENEA-INMRI and the BIPM in the medium-energy x-ray range. The results show the standards to be in general agreement within the stated uncertainty, although there is evidence of a trend in the results at different radiation qualities. (authors)

  9. Experimental comparison among the laboratories accredited within the framework of the European Co-operation for Accreditation on the calibration of a radiation protection dosimeters in the terms of the quantity air Kerma

    International Nuclear Information System (INIS)

    The European co-operation for Accreditation (EA) formalises the collaboration of the Accreditation Bodies of the Member States of the European Union and the European Free Trade Association covering all conformity assessment activities. This collaboration is based on a Memorandum of Understanding dated the 27 November 1997 and aims at developing and maintain Multilateral Agreements (MLAs) within EA and with non-members accreditation bodies. MLAs Signatories guarantee uniformity of accreditation by continuous and rigorous evaluation. Based on mutual confidence, the MLAs recognise the equivalence of the accreditation systems administered by EA Members and of certificates and reports issued by bodies accredited under these systems. A basic element of the program to establish and maintain mutual confidence among calibration services is the participation of the accredited laboratories in experimental interlaboratory comparisons (ILC) organised by EA members or other international organisations. The aim of these ILC is to verify the technical equivalence of calibration services within the EA. The ILC which it is dealt with in the present work was recently carried out over a period of two years, ending in May 2002. It interested the laboratories accredited in the ionising radiation field for calibration of dosimeters at radiation protection levels in terms of the quantity air kerma (Kair) due to 60Co and 137Cs gamma radiation. The ILC was planned by the EA expert group on Ionising radiation and radioactivity and approved by the EA General Assembly in December 1999 with the title Calibration of a Radiation Protection Dosimeter under the code IR3. The need of this comparison also resulted from an inquiry carried out in 1998 by the expert group among the different Accreditation Bodies members of EA and associated to EA. The organization of the ILC was carried out according to the EA rules by the Italian Accreditation Body in the ionising radiation field, the SIT-ENEA , in cooperation with the Italian National Metrology Institute in the ionising radiation field, the ENEA-INMRI, as the reference laboratory

  10. The air pollution index system in Hong Kong

    Energy Technology Data Exchange (ETDEWEB)

    Lee, F.Y.P.; Gervat, G.P. [Hong Kong Government, Wanchai (Hong Kong). Environmental Protection Dept.

    1995-12-31

    The Hong Kong Environmental Protection Department (EPD) is currently operating an air quality monitoring network in the territory. There are nine monitoring stations, each with air quality monitoring equipment, meteorological instruments and a data logger. Five minute averaged data are transmitted through telephone lines to the central computer at the EPD Air Laboratory and are also stored in the data logger on site, as backup. At present, the EPD releases its air quality measurements to the public via monthly and special press releases, and annual reports. However, as public awareness of air pollution problems has increased, there has been an urgent need for timely and simpler information about air pollution levels. The development and operation of an Air Pollution Index (API) system has addressed that need. This presentation discusses the API computation, the information and advice released to the general public and how they can access the API information. Some API results are also presented. (author)

  11. The use of air quality index (AQI) in environmental management

    International Nuclear Information System (INIS)

    The air quality index (AQI) is considered a global air quality index in a particular moment or day and in a specific monitoring station. The AQI is to be interpreted as a guiding air quality index for the general public. Specialists should take into account other factors when studying the pollution levels. The behaviour of air pollution is studied by using the AQI in two monitoring points in Regla, where the main pollutants are measured: SO2, NO2 and total suspended particulates. It was founded that particulates and NO2 are the pollutants that contribute most to the air quality deterioration, which occurs with greater frequency-days in the categories Poor and Bad, and show an increase in the categories Terrible and Critical. The necessary recommendations for the reduction of air pollution are given. The use of this AQI for assessing air pollution in settlements is recommended as a good tool for environmental information and management. A visual scale is proposed to improve and facilitate the public's understanding

  12. Hold Your Breath. A New Index of Air Quality

    Energy Technology Data Exchange (ETDEWEB)

    Buehn, A. [Utrecht School of Economics, Utrecht University, Utrecht (Netherlands); Reza Farzanega, M. [Dresden University of Technology and ZEW Mannheim, Mannheim (Germany)

    2011-12-15

    Environmental quality and climate change have long attracted attention in policy debates. Recently, air quality has emerged on the policy agenda. We calculate a new index of air quality using CO2 and SO2 emissions per capita as indicators and provide a ranking for 122 countries from 1985 to 2005.The empirical analysis supports the EKC hypothesis (Environmental Kuznets Curve) and shows a significant influence of determinants such as energy efficiency, industrial production, electricity produced from coal sources, and urbanization on air quality. According to our index, Luxemburg, Norway, Iceland, Switzerland, and Japan are among the top 5 countries in terms of air quality performance. The Democratic Republic of Congo, Eritrea, Ethiopia, Togo, and Nepal performed worst in 2005.

  13. Hold Your Breath. A New Index of Air Quality

    International Nuclear Information System (INIS)

    Environmental quality and climate change have long attracted attention in policy debates. Recently, air quality has emerged on the policy agenda. We calculate a new index of air quality using CO2 and SO2 emissions per capita as indicators and provide a ranking for 122 countries from 1985 to 2005.The empirical analysis supports the EKC hypothesis (Environmental Kuznets Curve) and shows a significant influence of determinants such as energy efficiency, industrial production, electricity produced from coal sources, and urbanization on air quality. According to our index, Luxemburg, Norway, Iceland, Switzerland, and Japan are among the top 5 countries in terms of air quality performance. The Democratic Republic of Congo, Eritrea, Ethiopia, Togo, and Nepal performed worst in 2005.

  14. Comparison of conversion coefficients for equivalent dose in terms of air kerma using a sitting and standing female adult voxel simulators exposure to photons in antero-posterior irradiation geometry

    International Nuclear Information System (INIS)

    Due to the difficulty in implementing invasive techniques for calculations of dose for some exposure scenarios, computational simulators have been created to represent as realistically as possible the structures of the human body and through radiation transport simulations to obtain conversion coefficients (CCs) to estimate dose. In most published papers simulators are implemented in the standing posture and this may not describe a real scenario of exposure. In this work we developed exposure scenarios in the Visual Monte Carlo (VMC) code using a female simulator in standing and sitting postures. The simulator was irradiated in the antero-posterior (AP) geometry by a plane source of monoenergetic photons with energy from 10 keV to 2 MeV. The conversion coefficients for equivalent dose in terms of air kerma (HT/Kair) were calculated for both scenarios and compared. The results show that the percentage difference of CCs for the organs of the head and thorax was not significant (less than 5%) since the anatomic position of the organs is the same in both postures. The percentage difference is more significant to the ovaries (71% for photon energy of 20 keV), to the bladder (39% at 60 keV) and to the uterus (37% at 100 keV) due to different processes of radiation interactions in the legs of the simulator when its posture is changed. For organs and tissues that are distributed throughout the entire body, such as bone (21% at 100 keV) and muscle (30% at 80 keV) the percentage difference of CCs reflects a reduction of interaction of photons with the legs of the simulator. Therefore, the calculation of conversion coefficients using simulators in the sitting posture is relevant for a more accurate dose estimation in real exposures to radiation. - Highlights: ? Scenarios of external photon exposures were performed in VMC code. ? The FAX simulator was irradiated in sitting and standing postures. ? The irradiation geometry used was the antero-posterior (AP). ? The conversion coefficients for sitting and standing postures were compared. ? Photoelectric and Compton effects were the main processes of energy deposition

  15. Comparison of conversion coefficients for equivalent dose in terms of air kerma for photons using a male adult voxel simulator in sitting and standing posture with geometry of irradiation antero-posterior

    International Nuclear Information System (INIS)

    The dose conversion coefficient (DCC) is important to quantify and assess effective doses associated with medical, professional and public exposures. The calculation of DCCs using anthropomorphic simulators and radiation transport codes is justified since in-vivo measurement of effective dose is extremely difficult and not practical for occupational dosimetry. DCCs have been published by the ICRP using simulators in a standing posture, which is not always applicable to all exposure scenarios, providing an inaccurate dose estimation. The aim of this work was to calculate DCCs for equivalent dose in terms of air kerma (H/Kair) using the Visual Monte Carlo (VMC) code and the VOXTISS8 adult male voxel simulator in sitting and standing postures. In both postures, the simulator was irradiated by a plane source of monoenergetic photons in antero-posterior (AP) geometry. The photon energy ranged from 15 keV to 2 MeV. The DCCs for both postures were compared and the DCCs for the standing simulator were higher. For certain organs, the difference of DCCs were more significant, as in gonads (48% higher), bladder (16% higher) and colon (11% higher). As these organs are positioned in the abdominal region, the posture of the anthropomorphic simulator modifies the form in which the radiation is transported and how the energy is deposited. It was also noted that the average percentage difference of conversion coefficients was 33% for the bone marrow, 11% for the skin, 13% for the bone surface and 31% for the muscle. For other organs, the percentage difference of the DCCs for both postures was not relevant (less than 5%) due to no anatomical changes in the organs of the head, chest and upper abdomen. We can conclude that is important to obtain DCCs using different postures from those present in the scientific literature. - Highlights: • Scenarios of external photon exposures were performed in VMC code. • The VOXTISS8 simulator was irradiated in standing and sitting postures. • The irradiation geometry used was the antero-posterior (AP). • The DCCs for standing and sitting postures were compared. • Significant differences between the DCCs in both postures were observed

  16. Hold your breath: A new index of air quality

    OpenAIRE

    Buehn, Andreas; Farzanegan, Mohammad Reza

    2012-01-01

    Environmental quality and climate change have long attracted attention in policy debates. Recently, air quality has emerged on the policy agenda. We calculate a new index of air quality using CO2 and SO2 emissions per capita as indicators and provide a ranking for 122 countries from 1985 to 2005. The empirical analysis supports the EKC hypothesis and shows a significant influence of determinants such as energy efficiency, industrial production, electricity produced from coal sources, and urba...

  17. Seasonal ARIMA for Forecasting Air Pollution Index: A Case Study

    OpenAIRE

    Muhammad H. Lee; Nur H.A. Rahman; Suhartono; Mohd T. Latif; Maria E. Nor; Nur A.B. Kamisan

    2012-01-01

    Problem statement: Both developed and developing countries are the major reason that affects the world environment quality. In that case, without limit or warning, this pollution may affect human health, agricultural, forest species and ecosystems. Therefore, the aim of this study was to determine the monthly and seasonal variations of Air Pollution Index (API) at all monitoring stations in Johor. Approach: In this study, time series models will be discussed to analyze future air quality and ...

  18. Alberta's air quality index : facts at your fingertip

    International Nuclear Information System (INIS)

    Alberta Environment measures the airborne concentrations of carbon dioxide, fine particulate matter, nitrogen dioxide, ozone and sulphur dioxide on a continuous basis at air quality monitoring stations in Edmonton, Calgary, Red Deer and Beaverlodge. Every hour, the readings are converted to an Air Quality Index (AQI) number to report on Alberta's outdoor air quality as either good, fair, poor or very poor. The categories relate to guidelines under Alberta's Environmental Protection and Enhancement Act and reflect the maximum acceptable levels specified by the National Ambient Air Quality Objectives. Current air quality conditions are available to the public through Alberta Environment's web site or by phoning a toll free number. Both Edmonton and Calgary report good air quality at least 90 per cent of the time. Occasionally, air quality in the two cities may reach the fair category, but it is seldom poor. Fair, poor or very poor air quality occurs with strong temperature inversion and light winds. Under these conditions, air pollutants, usually from automobiles, are trapped in a layer of stagnant air. Fair and poor air quality can also be caused by summer heat when photochemical smog forms by chemical reactions with oxides of nitrogen and volatile hydrocarbons. 1 ref., 1 tab., 1 fig

  19. Neutron kerma coefficient: Reference tissue for tumours

    International Nuclear Information System (INIS)

    Neutron kerma coefficients were calculated in different media: 4 malignant tumours, 5 normal tissues and 3 tissue substitute in the range 11 eV-29 MeV. The objective was to identify which is the material that better reproduces the behavior of these tumours and tissues. These tissues have clinical interest in interstitial brachytherapy applications with fast neutron source (Cf-252). The small differences of elemental composition among these tissues produce variation in the neutron kerma coefficients. The results show that the neutron kerma coefficients for malignant tumours are smaller than soft tissue from 6% to 9%. Also, the muscle is the tissue that best represents the dosimetric behavior for the tumours and tissues analyzed in this paper for neutron energies >1 keV, where this coefficients show minor variation.

  20. Seasonal ARIMA for Forecasting Air Pollution Index: A Case Study

    Directory of Open Access Journals (Sweden)

    Muhammad H. Lee

    2012-01-01

    Full Text Available Problem statement: Both developed and developing countries are the major reason that affects the world environment quality. In that case, without limit or warning, this pollution may affect human health, agricultural, forest species and ecosystems. Therefore, the aim of this study was to determine the monthly and seasonal variations of Air Pollution Index (API at all monitoring stations in Johor. Approach: In this study, time series models will be discussed to analyze future air quality and used in modeling and forecasting monthly future air quality in Malaysia. A Box-Jenkins ARIMA approach was applied in order to analyze the API values in Johor. Results: In all this three stations, high values recorded at sekolah menengah pasir gudang dua (CA0001. This situation indicates that the most polluted area in Johor located in Pasir Gudang. This condition appears to be the reason that Pasir Gudang is the most developed area especially in industrial activities. Conclusion: Time series model used in forecasting is an important tool in monitoring and controlling the air quality condition. It is useful to take quick action before the situations worsen in the long run. In that case, better model performance is crucial to achieve good air quality forecasting. Moreover, the pollutants must in consideration in analysis air pollution data.

  1. An innovative approach for determination of air quality health index.

    Science.gov (United States)

    Gorai, Amit Kumar; Kanchan; Upadhyay, Abhishek; Tuluri, Francis; Goyal, Pramila; Tchounwou, Paul B

    2015-11-15

    Fuzzy-analytical hierarchical process (F-AHP) can be extended to determine fuzzy air quality health index (FAQHI) for deducing health risk associated with local air pollution levels, and subjective parameters. The present work aims at determining FAQHI by considering five air pollutant parameters (SO2, NO2, O3, CO, and PM10) and three subjective parameters (population sensitivity, population density and location sensitivity). Each of the individual pollutants has varying impacts. Hence the combined health effects associated with the pollutants were estimated by aggregating the pollutants with different weights. Global weights for each evaluation alternatives were determined using fuzzy-AHP method. The developed model was applied to determine FAQHI in Howrah City, India from daily-observed concentrations of air pollutants over the three-year period between 2009 and 2011. The FAQHI values obtained through this method in Howrah City range from 1 to 3. Since the permissible value of FAQHI (as calculated for NAAQS) for residential areas is 1.78, higher index values are of public health concern to the exposed individuals. During the period of study, the observed FAQHI values were found to be higher than 1.78 in most of the day in the months of January to March, and October to December. However, the index values were below the recommended limit during rest of the months. In conclusion, FAQHI in Howrah city was above permissible limit in winter months and within acceptable values in summer and rainy months. Diurnal variations of FAQHI showed a similar trend during the three-year period of assessment. PMID:26186464

  2. The Air Quality Health Index and Asthma Morbidity: A Population-Based Study

    OpenAIRE

    To, Teresa; Shen, Shixin; Atenafu, Eshetu G.; Guan, Jun; McLimont, Susan; Stocks, Brian; Licskai, Christopher

    2012-01-01

    Background: Exposure to air pollution has been linked to the exacerbation of respiratory diseases. The Air Quality Health Index (AQHI), developed in Canada, is a new health risk scale for reporting air quality and advising risk reduction actions.

  3. Neutron kerma coefficients of compounds for shielding and dosimetry

    International Nuclear Information System (INIS)

    Highlights: • Neutron kerma coefficients of compounds were calculated. • Kerma coefficients are lowest in intermediate energy (10 eV–10 keV). • Kerma coefficients are large for compounds containing large low-Z elements. • Resonance in kerma coefficients is observed for the oxygen containing compounds. • At larger energies kerma coefficients are approximately the same. - Abstract: Alloys, concretes, glasses, neutron shielding material, polymers, nuclear track detectors, are being used for shielding and dosimetry applications. The neutron kerma coefficients of eighteen compounds have been calculated for neutrons energy less than 30 MeV; these compounds are used as shielding and dosimetric materials. The kerma coefficients are found lowest for all the compounds in intermediate energy (10 eV < E < 10 keV). The neutron kerma coefficients are higher for the compounds containing large weight fraction of low-Z elements. A resonance in neutron kerma coefficient is observed for the large amount of oxygen containing compounds. It is found that at high energies kerma coefficients are approximately same, but very large differences for energy less than 100 eV

  4. Survivor dosimetry. Part A. Fluence-to-kerma conversion coefficients

    International Nuclear Information System (INIS)

    An important step in the dosimetry evaluation is to relate the radiation passing through a unit volume of a material of interest (fluence) to the energy release (kerma) in the material, which determines the absorbed dose. The fluence-to-kerma conversion coefficients or 'kerma coefficients' used in the Dosimetry System 1986 (DS86) are taken from Kerr (1982). These kerma coefficients are based on body tissue compositions for Reference Man from the International Commission on Radiological Protection (1975) and Kerr (1982), the mass energy-absorption coefficients for photons from Hubbell (1982), and the elemental kerma coefficients for neutrons from Caswell et al. (1980). Hence, the kerma coefficients used in DS86 are approximately 20 years old. In order to provide an updated set of kerma coefficients for use in the Dosimetry System 2002 (DS02), a new evaluation has been completed. This new evaluation considered recently suggested changes in the composition of soft tissues of the body in ICRU Report 44 (International Commission on Radiation Units and Measurements 1989), the mass energy-absorption coefficients for photons by Hubbell and Seltzer (1996), and the elemental kerma coefficients for neutrons in ICRU Report 63 (International Commission on Radiation Units and Measurements 2000). The new DS02 kerma coefficients for soft tissue are presented as both point-wise data for use in Monte Carlo radiation transport calculations and multigroup data for use in discrete ordinates radiation transport calculations. (author)

  5. Preparation and determination of kerma for Iridium 192 sources of low dose rate for brachytherapy

    International Nuclear Information System (INIS)

    The practice of Brachytherapy with Iridium-192 sources of low dose rate (0.4 - 0.8 Gy/h) is a technique used in the treatment of diverse illnesses. in this work the preparation, quality control and calibration are presented in terms of kerma in air of Iridium-192 using as target these recycled Iridium-Platinum wires. The targets were obtained as decayed sources of different radio therapeutical centers in the country and they were characterized by Scanning electron microscopy in order to determine their chemical composition. Subsequently it was developed an experimental design to establish the effect of neutron flux, geometrical array and irradiation time over the activity and percentage of the sources homogeneity. The homogeneity was determined by auto radiography and by Gamma spectroscopy. Once the optimal irradiation conditions were established, it is determined the apparent activity and kerma in air using a well type ionization chamber with traceability to a primary laboratory. Iridium-192 sources were obtained with an average homogeneity 96 %, apparent activity 282.129 ± 0.531 M Bq and kerma in air 0.03200 ± 0.00006 m Gy m/h A. (Author)

  6. Kerma factors in interaction of neutrons with boron carbide

    International Nuclear Information System (INIS)

    Heat generation in neutron interactions with boron carbide B10; B11 and 12C is calculated. Kerma-factors (kerma-kinetic energy released in materials) were calculated for neutron energies between 10-4 eV and 15 MeV. No major simplifying assumptions are introduced, and the accuracy of the calculated kerma-factors depends only on availability and accuracy of the basic nuclear data. The ENDF/B-4 data and recent experimental information are used for the calculation of kerma-factors. Plots of these kerma-factors are presented in units of eVxb/atom and wtxsec/(cmxn) as a function of neutron energy

  7. Can the Air Pollution Index be used to communicate the health risks of air pollution?

    Science.gov (United States)

    Li, Li; Lin, Guo-Zhen; Liu, Hua-Zhang; Guo, Yuming; Ou, Chun-Quan; Chen, Ping-Yan

    2015-10-01

    The validity of using the Air Pollution Index (API) to assess health impacts of air pollution and potential modification by individual characteristics on air pollution effects remain uncertain. We applied distributed lag non-linear models (DLNMs) to assess associations of daily API, specific pollution indices for PM10, SO2, NO2 and the weighted combined API (APIw) with mortality during 2003-2011 in Guangzhou, China. An increase of 10 in API was associated with a 0.88% (95% confidence interval (CI): 0.50, 1.27%) increase of non-accidental mortality at lag 0-2 days. Harvesting effects appeared after 2 days' exposure. The effect estimate of API over lag 0-15 days was statistically significant and similar with those of pollutant-specific indices and APIw. Stronger associations between API and mortality were observed in the elderly, females and residents with low educational attainment. In conclusion, the API can be used to communicate health risks of air pollution. PMID:26057478

  8. Tolerance Levels of Roadside Trees to Air Pollutants Based on Relative Growth Rate and Air Pollution Tolerance Index

    OpenAIRE

    SULISTIJORINI; ZAINAL ALIM MAS’UD; NIZAR NASRULLAH; AHMAD BEY; SOEKISMAN TJITROSEMITO

    2008-01-01

    Motor vehicles release carbon monoxide, nitrogen dioxide, sulphur dioxide, and particulate matters to the air as pollutants. Vegetation can absorb these pollutants through gas exchange processes. The objective of this study was to examine the combination of the relative growth rate (RGR) and physiological responses in determining tolerance levels of plant species to air pollutants. Physiological responses were calculated as air pollution tolerance index (APTI). Eight roadside tree species wer...

  9. Vessel heave, and index for air bubble attenuation corrections

    OpenAIRE

    Ona, Egil

    1991-01-01

    The possible use of vessel heave as a correction indicator for air bubble attenuation of acoustic signals from hull mounted transducers is investigated. Vessel heave was monitored along with the echo energy from the air bubble layer close to the transducer surface. Initial comparisons under different weather conditions are presented.

  10. Air refractivity index in optical region: formulas and measurement in CZ.

    Czech Academy of Sciences Publication Activity Database

    Pešice, Petr; Fišer, Ond?ej; Chládová, Zuzana; Brázda, Vladimír

    Portsmouth : University of Portsmouth, 2012, COST IC0802/1-COST IC0802/7. [MCM 7. Portsmouth (GB), 16.04.2012-18.04.2012] R&D Projects: GA MŠk OC09027 Institutional support: RVO:68378289 Keywords : Refractivity index * structure index * free-space optics * temperature * humidity * air pressure Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  11. A comparative study for air pollution tolerance index of some terrestrial plant species

    Directory of Open Access Journals (Sweden)

    R.N. Lohe

    2015-09-01

    Full Text Available Although water and land pollution are very dangerous, air pollution has its own peculiarities due to its transboundary dispersion of pollutants over the entire world. In any well planned urban set up, industrial pollution takes a back seat and vehicular emissions take precedence as the major cause of urban air pollution. In the present study, Air pollution tolerance index was calculated for various plant species growing at two sites Nagal village at Sahastradhara Road and the Clock Tower (the experimental site of Dehradun city, India. The leaf samples were collected from 7 commonly present tree species. The results showed significant effects of various air pollutants on the vegetation in terms of four biochemical parameters analysed. Four physiological and biochemical parameters, which are leaf relative water content, Ascorbic acid content, total leaf chlorophyll content and leaf extract pH were used to compute the air pollution tolerance index values. Statistically significant difference was observed between control and experimental group for Ascorbic acid, t(6=-4.848,p=.003. Paired t test for air pollution tolerance index between the two groups showed a statistically significant difference, t (6 = -4.548, p=.004. On the basis of air pollution tolerance index values for above mentioned seven tree species, Eucalyptus globus exhibited the highest degree of tolerance at all the sites followed by Ficus religiosa > Mangifera indica > Polyalthia longifolia > Phyllanthus emblica > Citrus limon > Lantana camara.

  12. Preparation and determination of kerma for Iridium 192 sources of low dose rate for brachytherapy; Preparacion y determinacion del kerma de fuentes de iridio-192 de baja tasa de dosis para braquiterapia

    Energy Technology Data Exchange (ETDEWEB)

    Tendilla, J.I.; Tovar M, V.; Mitsoura, E.; Aguilar H, F.; Alanis M, J. [Instituto Nacional de Investigaciones Nucleares, C.P. 52045-1, Salazar, Esrado de Mexico, D.F. (Mexico)

    2000-07-01

    The practice of Brachytherapy with Iridium-192 sources of low dose rate (0.4 - 0.8 Gy/h) is a technique used in the treatment of diverse illnesses. in this work the preparation, quality control and calibration are presented in terms of kerma in air of Iridium-192 using as target these recycled Iridium-Platinum wires. The targets were obtained as decayed sources of different radio therapeutical centers in the country and they were characterized by Scanning electron microscopy in order to determine their chemical composition. Subsequently it was developed an experimental design to establish the effect of neutron flux, geometrical array and irradiation time over the activity and percentage of the sources homogeneity. The homogeneity was determined by auto radiography and by Gamma spectroscopy. Once the optimal irradiation conditions were established, it is determined the apparent activity and kerma in air using a well type ionization chamber with traceability to a primary laboratory. Iridium-192 sources were obtained with an average homogeneity 96 %, apparent activity 282.129 {+-} 0.531 M Bq and kerma in air 0.03200 {+-} 0.00006 m Gy m/h A. (Author)

  13. Impact of fine particulate fluctuation and other variables on Beijing's air quality index.

    Science.gov (United States)

    Chen, Bo; Lu, Shaowei; Li, Shaoning; Wang, Bing

    2015-04-01

    We analyzed fluctuation in Beijing's air quality over 328 days, based on air quality grades and air quality data from 35 atmospheric monitoring stations. Our results show the air over Beijing is subject to pollution 152 days of the year, or 46.34%. Among all pollutants, fine particulates, solid or liquid, 2.5 ?m or less in size (PM2.5), appeared most frequently as the primary pollutant: 249 days, or 76% of the sample year (328 days). Nitrogen dioxide (NO2) and coarse particulates (PM10) cause the least pollution, appearing only 7 and 3 days, or 2 and 1% of the sample year, respectively. In Beijing, fine particulates like PM2.5 vary seasonally: 154.54?±?18.60 in winter?>?145.22?±?18.61 in spring?>?140.16?±?20.76 in autumn?>?122.37?±?13.42 in summer. Air quality is best in August and worst in December, while various districts in Beijing experience different air quality. To be specific, from south to north and from west to east, air quality tends to improve. Meteorological elements have a constraining effect on air pollutants, which means there is a linear correlation between the air quality index and humidity, rainfall, wind speed, and temperature. Under a typical pollution scenario, the higher the air quality index (AQI) value, the lower the wind speed and the greater the relative humidity; the lower the AQI value, the higher the wind speed and lower the relative humidity. Analysis of influencing factors reveals that the air pollution is mainly particulate matter produced by burning coal, vehicle emissions, volatile oils and gas, fast development of food services, emissions from the surrounding region, and natural dust clouds formed in arid areas to the northwest. Topography affects the distribution of meteorological conditions, in turn varying air quality over the region from one location to another. Human activities also exercise impact on urban air quality with dual functions. PMID:25563832

  14. Fundamental relationships between linear energy transfer, absorbed dose, kerma, and exposure. Application to changes of mediums

    International Nuclear Information System (INIS)

    After briefly defining the quantities used in dosimetry and presenting them with a view to their simple adaptation to health physics problems, the authors establish simple mathematical relationships to express the absorbed dose, kerma and exposure in the case of electrons and photons, and also relationships between these various quantities considered in air. They then proceed to study the variations in these quantities at the interface between the air and the soft tissues of the organism and in depth in the tissues. They give the numerical values of the discontinuities liable to appear at the interface and the values obtained, relative to air, after electronic equilibrium is established in depth in the tissues. An example of application to dosimetry is also given in the case of an aluminium-walled ionization chamber. To conclude, the conditions to be fulfilled in order to make a direct measurement of the absorbed dose in the tissues are presented and discussed. (authors)

  15. Arima and integrated arfima models for forecasting air pollution index in Shah Alam, Selangor

    International Nuclear Information System (INIS)

    Air pollution is one of the major issues that has been affecting human health, agricultural crops, forest species and ecosystems. Since 1980, Malaysia has had a series of haze episodes and the worst ever was reported in 1997. As a result, the government has established the Malaysia Air Quality Guidelines, the Air Pollution Index (API) and Haze Action Plan, to improve the air quality. The API was introduced as an index system for classifying and reporting the ambient air quality in Malaysia. The API for a given period is calculated based on the sub-index value (sub-API) for all the five air pollutants, namely sulphur dioxide (SO2), nitrogen dioxide (NO2), ozone (O3), carbon monoxide (CO) and particulate matter below 10 micron size (PM10). The forecast of air pollution can be used for air pollution assessment and management. It can serve as information and warning to the public in cases of high air pollution levels and for policy management of many different chemical compounds. Hence, the objective of this project is to fit and illustrate the use of time series models in forecasting the API in Shah Alam, Selangor. The data used in this study consists of 70 monthly observations of API (from March 1998 to December 2003) published in the Annual Reports of the Department of Environment, Selangor. The time series models that were being considered were the Integrated Autoregressive Moving Average (ARIMA) and the Integrated Long Memory Model (ARFIMA) models. The lowest MAE, RMSE and MAPE values were used as the model selection criteria. Between these two models considered, the integrated ARFIMA model appears to be the better model as it has the lowest MAPE value. However, the actual value of May 2003 falls outside the 95% forecast interval, probably due to emissions from mobile sources (i.e., motor vehicles), industrial emissions, burning of solid wastes and forest fires. (author)

  16. The spatial- time distribution of vertical gradient of refraction index of air in territory of Mongolia

    International Nuclear Information System (INIS)

    The results of calculation of the vertical gradient of refraction index of air in 2-300 m layer of troposphere by 3 year (1987-1989) data of 8 meteorological stations in the Mongolia is been showed. Year course and integral distribution of g of this stations are described. 4 figs, 2 tables. (J.U)

  17. Frequency measurement of refraction index of air for high-resolution laser interferometry.

    Czech Academy of Sciences Publication Activity Database

    ?íp, Ond?ej; Petr?, František; Matoušek, V.; Lazar, Josef

    Bellingham : SPIE, 2004, s. 273-277. ISBN 0-8194-5380-3. ISSN 0277-786X. [Optical Micro- and Nanometrology in Manufacturing Technology. Strasbourg (FR), 29.04.2004-30.04.2004] R&D Projects: GA AV ?R(CZ) IAB2065001 Keywords : index of refraction of air * high-resolution laser interferometry * Edlen formula Subject RIV: BH - Optics, Masers, Lasers

  18. Calibration of Kerma Area Product Meters with a Patient Dose Calibrator

    International Nuclear Information System (INIS)

    Kerma area product (KAP) meters used in X ray imaging for monitoring patient exposure were calibrated using different reference meters. Typically, the reference KAP value is the product of the air kerma and the X ray field size. In the tandem method, the reference value is measured with another KAP meter; in this study, a large KAP meter of novel type, the patient dose calibrator (PDC), was used for this purpose. The properties of the PDC meter were studied and the use of the meter as a reference meter was reviewed throughout the whole train of events from calibration in a secondary standard dosimetry laboratory to using the meter in clinical situations. Compared to conventional KAP meters, the advantages of the PDC are the lower energy dependence of response and the possibility to use larger field sizes. In laboratory measurements, the properties of the PDC meter were proved suitable to be used as a reference meter. The uncertainty related to the differences in X ray tube output used in calibration at the laboratory and in measurements at the clinic is highlighted. The calibration coefficients for field KAP meters calibrated by the PDC meter and by other meters were congruent on the average within 4%. Clinical measurements emphasized the need for in situ calibration of clinical KAP meters. Particularly in the under-couch situation, the calibration should be performed with the couch in the beam. (author)

  19. Development of a calibration methodology and tests of kerma area product meters; Desenvolvimento de uma metodologia de calibracao e testes de medidores de produto Kerma-Area

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Nathalia Almeida

    2013-07-01

    The quantity kerma area product (PKA) is important to establish reference levels in diagnostic radiology exams. This quantity can be obtained using a PKA meter. The use of such meters is essential to evaluate the radiation dose in radiological procedures and is a good indicator to make sure that the dose limit to the patient's skin doesn't exceed. Sometimes, these meters come fixed to X radiation equipment, which makes its calibration difficult. In this work, it was developed a methodology for calibration of PKA meters. The instrument used for this purpose was the Patient Dose Calibrator (PDC). It was developed to be used as a reference to check the calibration of PKA and air kerma meters that are used for dosimetry in patients and to verify the consistency and behavior of systems of automatic exposure control. Because it is a new equipment, which, in Brazil, is not yet used as reference equipment for calibration, it was also performed the quality control of this equipment with characterization tests, the calibration and an evaluation of the energy dependence. After the tests, it was proved that the PDC can be used as a reference instrument and that the calibration must be performed in situ, so that the characteristics of each X-ray equipment, where the PKA meters are used, are considered. The calibration was then performed with portable PKA meters and in an interventional radiology equipment that has a PKA meter fixed. The results were good and it was proved the need for calibration of these meters and the importance of in situ calibration with a reference meter. (author)

  20. Effects of Age, Gender and Body Mass Index on Reaction to Air Condition

    OpenAIRE

    Nkwam C. Uwaoma; Anthony Nkwocha

    2011-01-01

    Abstract: This study investigated the effect of age, gender, and body mass index (BMI) on reaction to air condition. Forty eight undergraduates (21 males and 27 females) randomly selected from Imo State University, Owerri, Nigeria within the age range of 17-30 years participated in the study. 26 of them were of normal weight (BMI 24). They were exposed to an air conditioned room for two hours and then their reaction to cold measured using Response to Cold questionnaire. Employing t-test and A...

  1. Analysis and evolution of air quality monitoring networks using combined statistical information indexes

    Directory of Open Access Journals (Sweden)

    Axel Osses

    2013-10-01

    Full Text Available In this work, we present combined statistical indexes for evaluating air quality monitoring networks based on concepts derived from the information theory and Kullback–Liebler divergence. More precisely, we introduce: (1 the standard measure of complementary mutual information or ‘specificity’ index; (2 a new measure of information gain or ‘representativity’ index; (3 the information gaps associated with the evolution of a network and (4 the normalised information distance used in clustering analysis. All these information concepts are illustrated by applying them to 14 yr of data collected by the air quality monitoring network in Santiago de Chile (33.5 S, 70.5 W, 500 m a.s.l.. We find that downtown stations, located in a relatively flat area of the Santiago basin, generally show high ‘representativity’ and low ‘specificity’, whereas the contrary is found for a station located in a canyon to the east of the basin, consistently with known emission and circulation patterns of Santiago. We also show interesting applications of information gain to the analysis of the evolution of a network, where the choice of background information is also discussed, and of mutual information distance to the classifications of stations. Our analyses show that information as those presented here should of course be used in a complementary way when addressing the analysis of an air quality network for planning and evaluation purposes.

  2. Tolerance Levels of Roadside Trees to Air Pollutants Based on Relative Growth Rate and Air Pollution Tolerance Index

    Directory of Open Access Journals (Sweden)

    SULISTIJORINI

    2008-09-01

    Full Text Available Motor vehicles release carbon monoxide, nitrogen dioxide, sulphur dioxide, and particulate matters to the air as pollutants. Vegetation can absorb these pollutants through gas exchange processes. The objective of this study was to examine the combination of the relative growth rate (RGR and physiological responses in determining tolerance levels of plant species to air pollutants. Physiological responses were calculated as air pollution tolerance index (APTI. Eight roadside tree species were placed at polluted (Jagorawi highway and unpolluted (Sindangbarang field area. Growth and physiological parameters of the trees were recorded, including plant height, leaf area, total ascorbate, total chlorophyll, leaf-extract pH, and relative water content. Scoring criteria for the combination of RGR and APTI method was given based on means of the two areas based on two-sample t test. Based on the total score of RGR and APTI, Lagerstroemia speciosa was categorized as a tolerant species; and Pterocarpus indicus, Delonix regia, Swietenia macrophylla were categorized as moderately tolerant species. Gmelina arborea, Cinnamomum burmanii, and Mimusops elengi were categorized as intermediate tolerant species. Lagerstroemia speciosa could be potentially used as roadside tree. The combination of RGR and APTI value was better to determinate tolerance level of plant to air pollutant than merely APTI method.

  3. Air trapping on computed tomography images of healthy individuals: effects of respiration and body mass index

    Energy Technology Data Exchange (ETDEWEB)

    Hashimoto, M.; Tate, E.; Watarai, J.; Sasaki, M

    2006-10-15

    Aim: To evaluate the relationships of changes in the lung area during respiration and of individual body mass index (BMI) to air trapping on expiratory computed tomography (CT) in young non-smoking adults of either gender. Methods: The volunteers were 10 women and 10 men (mean age 25.7 years) who were healthy lifelong non-smokers. We obtained both end-inspiratory and end-expiratory CT images at three levels: the upper, middle and lower lung. The ratio of cross-sectional lung area upon expiration to cross-sectional lung area upon inspiration (lung area ratio) was determined for each lung at each of the three levels. In cases showing air trapping, we calculated the percentage of area of air in relation to the total lung area in each section. BMI was calculated for each participant. Results: Air trapping was present in dependent areas of the lungs of 6 women and 5 men. The mean percentage of area of air trapped was statistically greater for men (9.8 {+-} 9.2%) than for women (4.9 {+-} 5.2%). The mean lung area ratio was 0.52 {+-} 0 14 among volunteers with air trapping (66 sections) and 0.69 {+-} 0.12 among those without air trapping (54 sections) (p < 0.001). At each lung level, the mean lung area ratio was greater in individuals with air trapping than in those without. Mean BMI was also greater in these people (p = 0.009). Conclusion: Change in the respiratory lung area and BMI contribute to development of air trapping.

  4. Air trapping on computed tomography images of healthy individuals: effects of respiration and body mass index

    International Nuclear Information System (INIS)

    Aim: To evaluate the relationships of changes in the lung area during respiration and of individual body mass index (BMI) to air trapping on expiratory computed tomography (CT) in young non-smoking adults of either gender. Methods: The volunteers were 10 women and 10 men (mean age 25.7 years) who were healthy lifelong non-smokers. We obtained both end-inspiratory and end-expiratory CT images at three levels: the upper, middle and lower lung. The ratio of cross-sectional lung area upon expiration to cross-sectional lung area upon inspiration (lung area ratio) was determined for each lung at each of the three levels. In cases showing air trapping, we calculated the percentage of area of air in relation to the total lung area in each section. BMI was calculated for each participant. Results: Air trapping was present in dependent areas of the lungs of 6 women and 5 men. The mean percentage of area of air trapped was statistically greater for men (9.8 ± 9.2%) than for women (4.9 ± 5.2%). The mean lung area ratio was 0.52 ± 0 14 among volunteers with air trapping (66 sections) and 0.69 ± 0.12 among those without air trapping (54 sections) (p < 0.001). At each lung level, the mean lung area ratio was greater in individuals with air trapping than in those without. Mean BMI was also greater in these people (p = 0.009). Conclusion: Change in the respiratory lung area and BMI contribute to development of air trapping

  5. Comparison of the Revised Air Quality Index with the PSI and AQI indices

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Wan-Li; Chen, Yu-Song; Chang, Shiang-Hung [Dept of Environmental Science and Engineering, Tunghai University, Taichung 407 (China); Zhang, Junfeng [Division of Environmental and Occupational Health, University of Medicine and Dentistry of New Jersey, NJ 08854 (United States); Lyons, T.J. [Environmental Science, Murdoch University, Murdoch, WA 6150 (Australia); Pai, Joy-Lynn [Sunway Environmental Technology Co., Ltd., Taipei 104 (China)

    2007-09-01

    Air pollution indices are commonly used to indicate the level of severity of air pollution to the public. The Pollution Standards Index (PSI) was initially established in response to a dramatic increase in the number of people suffering respiratory irritation due to the deteriorating air quality. The PSI was subsequently revised and implemented by the USEPA in 1999, and became known as the Air Quality Index (AQI) that includes data relating to particle suspension, PM{sub 2.5}, and a selective options of either 8-hour or 1-hour ozone concentration during increased O{sub 3} periods. Yet, the costs of launching a network of PM{sub 2.5} monitoring stations are prohibitively high for many countries to implement the AQI from the PSI system in the foreseeable future. Therefore, the purpose of this research is to discuss the optimal method of assessing air quality using the latest developed Revised AQI (RAQI), a system that serves as an alternative to the PSI and AQI systems. The feasibility, effectiveness, and the differences between RAQI, AQI, and PSI in their applications to several air pollution conditions are also studied in this research. The results show that southern Taiwan's suspended particulates have significantly greater impact on PM{sub 2.5}/PM{sub 10} ratios than in central and northern metropolitan areas, and that the ratios are higher in Taiwan as a whole compared to many other countries. We also found that the RAQI shows more significant results compared to the PSI and AQI as it has a wider coverage of the range of pollutant concentration levels. (author)

  6. Experimental hydrogen kerma factors for incident neutron energies from 25 to 75 MeV

    International Nuclear Information System (INIS)

    Hydrogen kerma factors and their uncertainties are deduced on an experimental basis, starting from our previously measured differential cross sections completed with available data from the literature, in the incident neutron energy range 25 to 75 MeV. The deduced experimental kerma factors are compared with theoretical predictions. A simple to use parametrization of the hydrogen kerma factor values in the incident neutron energy range 0.3 to 100 MeV is also proposed. (author)

  7. The air quality health index and emergency department visits for urticaria in Windsor, Canada.

    Science.gov (United States)

    Kousha, Termeh; Valacchi, Giuseppe

    2015-01-01

    Ambient air pollution exposure has been associated with several health conditions, limited not only to respiratory and cardiovascular systems but also to cutaneous tissues. However, few epidemiological studies examined pollution exposure on skin problems. Basically, the common mechanism by which pollution may affect skin physiology is by induction of oxidative stress and inflammation. Urticaria is among the skin pathologies that have been associated with pollution. Based on the combined effects of three ambient air pollutants, ozone (O?), nitrogen dioxide (NO?), and fine particulate matter (PM) with a median aerodynamic diameter of less than 2.5 ?m (PM(2.5)), on mortality, the Air Quality Health Index (AQHI) in Canada was developed. The aim of this study was to examine the associations of short-term changes in AQHI with emergency department (ED) visits for urticaria in Windsor-area hospitals in Canada. Diagnosed ED visits were retrieved from the National Ambulatory Care Reporting System (NACRS). A time-stratified case-crossover design was applied to 2905 ED visits (males = 1215; females = 1690) for urticaria from April 2004 through December 2010. Odds ratios (OR) and their corresponding 95% confidence intervals (95%CI) for ED visits associated with increase by one unit of risk index were calculated employing conditional logistic regression. Positive and significant results were observed between AQHI levels and OR for ED visits for urticaria in Windsor for lags 2 and 3 days. A distributed lag nonlinear model technique was applied to daily counts of ED visits for lags 0 to 10 and significant results were obtained from lag 2 to lag 5 and for lag 9. These findings demonstrated associations between ambient air pollution and urticarial confirming that air pollution affects skin conditions. PMID:25849769

  8. Competency Index for Air Conditioning and Refrigeration Programs in Missouri. A Crosswalk of Selected Instructional Materials against Missouri's Competency Profile.

    Science.gov (United States)

    Missouri Univ., Columbia. Instructional Materials Lab.

    This index was developed to help air conditioning and refrigeration instructors in Missouri use existing instructional materials and keep track of student progress on the VAMS system. The list was compiled by a committee of instructors who selected appropriate references and identified areas that pertained to Missouri competencies. The index lists…

  9. Compressed Air Energy Storage System Control and Performance Assessment Using Energy Harvested Index

    Directory of Open Access Journals (Sweden)

    Hanif SedighNejad

    2014-01-01

    Full Text Available In this paper a new concept for control and performance assessment of compressed air energy storage (CAES systems in a hybrid energy system is introduced. The proposed criterion, based on the concept of energy harvest index (HEI, measures the capability of a storage system to capture renewable energy. The overall efficiency of the CAES system and optimum control and design from the technical and economic point of view is presented. A possible application of this idea is an isolated community with significant wind energy resource. A case study reveals the usefulness of the proposed criterion in design, control and implementation of a small CAES system in a hybrid power system (HPM for an isolated community. Energy harvested index and its effectiveness in increasing the wind penetration rate in the total energy production is discussed.

  10. Development of a calibration methodology and tests of kerma area product meters

    International Nuclear Information System (INIS)

    The quantity kerma area product (PKA) is important to establish reference levels in diagnostic radiology exams. This quantity can be obtained using a PKA meter. The use of such meters is essential to evaluate the radiation dose in radiological procedures and is a good indicator to make sure that the dose limit to the patient's skin doesn't exceed. Sometimes, these meters come fixed to X radiation equipment, which makes its calibration difficult. In this work, it was developed a methodology for calibration of PKA meters. The instrument used for this purpose was the Patient Dose Calibrator (PDC). It was developed to be used as a reference to check the calibration of PKA and air kerma meters that are used for dosimetry in patients and to verify the consistency and behavior of systems of automatic exposure control. Because it is a new equipment, which, in Brazil, is not yet used as reference equipment for calibration, it was also performed the quality control of this equipment with characterization tests, the calibration and an evaluation of the energy dependence. After the tests, it was proved that the PDC can be used as a reference instrument and that the calibration must be performed in situ, so that the characteristics of each X-ray equipment, where the PKA meters are used, are considered. The calibration was then performed with portable PKA meters and in an interventional radiology equipment that has a PKA meter fixed. The results were good and it was proved the need for calibration of these meters and the importance of in situ calibration with a reference meter. (author)

  11. Kerma-factors in neutron interactions with lithium hydride

    International Nuclear Information System (INIS)

    Models to calculate heat generation in a substance have been developed for all kinds of neutron reactions in any energy range. The calculational model for kerma-factors is based on a precise solution of kinematic equations. The calculated kerma-factors for 6Li, 7Li, 1H (in terms of eVxb/atom) and for LiH with natural Li (in Wxs/cmxneutr) in the energy range from 10-4 to 107 eV are presented. In neutron interactions with 6Li the major contributions to heat generation were assumed to be from the 6Li(n,t)He reaction; with 7Li - from the reactions of elastic scattering, inelastic scattering on the level E=0.478 MeV, (n,n't) and (n,?); with hydrogen the main contribution is made from the reactions of elastic scattering and capture. Data of the ENDF/B-4 library and latest experimental results were used in the calculations. It is pointed out that the accuracy of the calculations depends only on the availability and accuracy of corresponding nuclear data

  12. A method to determine the water kerma in a phantom for X-rays with energies up to 40 keV

    International Nuclear Information System (INIS)

    In brachytherapy, as in any form of radiation therapy, accurate dosimetry in terms of absorbed dose to water is required. The output of brachytherapy sources has, up to now, been specified as the reference air kerma rate at 1 m distance. For this reason, the Physikalisch-Technische Bundesanstalt is developing a primary standard to determine the absorbed dose to water at the point of measurement within a water phantom. A candidate for the standard to be newly established is a water-equivalent parallel-plate ionization chamber with continuously adjustable electrode spacing, forming an extrapolation chamber in a phantom of water-equivalent material. In this work, a method is introduced to determine the absorbed dose to water with an extrapolation chamber in a phantom of water-equivalent material. Thereby, a conversion factor C(xi+1, xi) is applied to the difference of the ionization charges measured at two different plate separations xi and xi+1. In contrast to already described methods, the applied method is based on fundamental dosimetric relations without the use of a wall-less chamber approximation. It will be shown that by using the wall-less chamber approximation, a term contributing to the absorbed dose to water is overlooked. This term is given by the net energy fluence of the secondary electrons at the surface of the measuring volume. The introduced method is verified experimentally by a comparison with water kerma values obtained from air kerma measurements free in air and applying a conversion factor to water kerma obtained by Monte Carlo (MC) calculations for the conditions of the experiment. Evidence is produced showing that the new model significantly increases the consistency of experimental and MC results. (author)

  13. Using Social Media to Detect Outdoor Air Pollution and Monitor Air Quality Index (AQI): A Geo-Targeted Spatiotemporal Analysis Framework with Sina Weibo (Chinese Twitter).

    Science.gov (United States)

    Jiang, Wei; Wang, Yandong; Tsou, Ming-Hsiang; Fu, Xiaokang

    2015-01-01

    Outdoor air pollution is a serious problem in many developing countries today. This study focuses on monitoring the dynamic changes of air quality effectively in large cities by analyzing the spatiotemporal trends in geo-targeted social media messages with comprehensive big data filtering procedures. We introduce a new social media analytic framework to (1) investigate the relationship between air pollution topics posted in Sina Weibo (Chinese Twitter) and the daily Air Quality Index (AQI) published by China's Ministry of Environmental Protection; and (2) monitor the dynamics of air quality index by using social media messages. Correlation analysis was used to compare the connections between discussion trends in social media messages and the temporal changes in the AQI during 2012. We categorized relevant messages into three types, retweets, mobile app messages, and original individual messages finding that original individual messages had the highest correlation to the Air Quality Index. Based on this correlation analysis, individual messages were used to monitor the AQI in 2013. Our study indicates that the filtered social media messages are strongly correlated to the AQI and can be used to monitor the air quality dynamics to some extent. PMID:26505756

  14. Using Social Media to Detect Outdoor Air Pollution and Monitor Air Quality Index (AQI): A Geo-Targeted Spatiotemporal Analysis Framework with Sina Weibo (Chinese Twitter)

    Science.gov (United States)

    Tsou, Ming-Hsiang; Fu, Xiaokang

    2015-01-01

    Outdoor air pollution is a serious problem in many developing countries today. This study focuses on monitoring the dynamic changes of air quality effectively in large cities by analyzing the spatiotemporal trends in geo-targeted social media messages with comprehensive big data filtering procedures. We introduce a new social media analytic framework to (1) investigate the relationship between air pollution topics posted in Sina Weibo (Chinese Twitter) and the daily Air Quality Index (AQI) published by China’s Ministry of Environmental Protection; and (2) monitor the dynamics of air quality index by using social media messages. Correlation analysis was used to compare the connections between discussion trends in social media messages and the temporal changes in the AQI during 2012. We categorized relevant messages into three types, retweets, mobile app messages, and original individual messages finding that original individual messages had the highest correlation to the Air Quality Index. Based on this correlation analysis, individual messages were used to monitor the AQI in 2013. Our study indicates that the filtered social media messages are strongly correlated to the AQI and can be used to monitor the air quality dynamics to some extent. PMID:26505756

  15. Evaluation of air pollution tolerance index of selected plant species along roadsides in Thiruvananthapuram, Kerala.

    Science.gov (United States)

    Jyothi, S Jissy; Jaya, D S

    2010-05-01

    To develop the usefulness of plants as bioindicators requires an appropriate selection of plant species which entail an utmost importance for a particular situation. In the present study a periodic evaluation of air pollution tolerance index [APTI] of selected tree species such as Polyalthia longifolia, (Sonner) Thw., Alstonia scholaris, R. Br., Mangifera indica, L., and shrubs Clerodendron infortunatum, L., Eupatorium odoratum, L., and Hyptis suaveolens, (L.) Poit., growing adjacent to the National Highway-47 passing through Thiruvananthapuram District which lies on the south-west coast of India, was carried out with a view to find out the air pollution tolerance as well as sensitivity of the plant species during different seasons. Among the trees in the roadside areas studied, Polyalthia longifolia, (Sonner) Thw., expressed highest APTI values and proved to be a tolerant variety and the others as sensitive species to air pollutants. In the case of shrubs, Clerodendron infortunatum, L., exhibited highest APTI values (7.34) and found to be more tolerant compared to the other two shrub species studied. PMID:21047015

  16. The ambient air quality accounts for the Nova Scotia Genuine Progress Index

    International Nuclear Information System (INIS)

    The Nova Scotia Genuine Progress Index (GPI) is a measure of sustainable development which provides a complete and accurate picture of our well-being as a society. The GPI assigns explicit values to environmental quality, population health, livelihood security, equity, free time, and educational attainment. The Nova Scotia GPI includes 22 social, economic and environmental components, including ambient air quality. This report investigates Nova Scotia's ambient air concentrations and emissions of carbon monoxide (CO), total particulate matter (PM), sulphur dioxide (SO2), nitrogen oxides (NOx), and volatile organic compounds (VOC). The costs of damages caused by the these key air pollutants are also examined. Exposure to these pollutants results in negative impacts on human health, damage to materials, agricultural crops and changes in forest productivity. From 1979 to 1996, national ambient concentrations of each of these pollutants decreased significantly. However, the national average concentration of ground-level ozone increased by 34 per cent during the same time period. In Nova Scotia, concentrations of CO, PM and SO2 have declined dramatically since 1979, but the trends for NO2 and ground-level ozone do not show significant declines. On a per capita basis, SOx emissions from electric power generation in the province are more than 8 times the Canadian average. The province also had higher per capita emissions of CO, PM, SOx and VOCs than all reporting OECD countries. Electric power generation is the greatest source of fuel combustion emissions in the province, followed by industrial and transportation sources. This report also described some individual actions that can be taken to reduce air pollutant emissions. 174 refs., 37 tabs., 60 figs

  17. Indexed

    CERN Document Server

    Hagy, Jessica

    2008-01-01

    Jessica Hagy is a different kind of thinker. She has an astonishing talent for visualizing relationships, capturing in pictures what is difficult for most of us to express in words. At indexed.blogspot.com, she posts charts, graphs, and Venn diagrams drawn on index cards that reveal in a simple and intuitive way the large and small truths of modern life. Praised throughout the blogosphere as “brilliant,” “incredibly creative,” and “comic genius,” Jessica turns her incisive, deadpan sense of humor on everything from office politics to relationships to religion. With new material along with some of Jessica’s greatest hits, this utterly unique book will thrill readers who demand humor that makes them both laugh and think.

  18. Air cavity-based Fabry-Perot interferometer sensor fabricated using a sawing technique for refractive index measurement

    Science.gov (United States)

    Jung, Eun Joo; Lee, Woo-Jin; Kim, Myoung Jin; Hwang, Sung Hwan; Rho, Byung Sup

    2014-01-01

    We have demonstrated a refractive index sensor based on a fiber optic Fabry-Perot (FP) interferometer with an open air cavity fabricated using a one-step mechanical sawing technique. The sensor head consists of a short FP cavity near the fiber patch cord tip, which was assembled by joining a ceramic ferrule and a single-mode fiber together. Owing to the open air cavity in the sensor head, various liquid samples with different refractive index can fill in-line air cavity, which makes the device usable as a refractometer. Moreover, due to the sensor head encircled with the robust ceramic ferrule, the device is attractive for sensing measurement in harsh environments. The sensor was tested in different refractive index solutions. The experimental result shows that the attenuation peak wavelength of the sensor is shifted toward a shorter wavelength with increasing refractive index, and the refractive index sensitivity is ˜92.5 nm/refractive index unit (RIU) and 73.75 dB/RIU. The proposed sensor can be used as an in-line refractometer for many potential applications in the sensing field.

  19. Proceedings of the 20th DOE/NRC nuclear air cleaning conference: An index to the 1st--20th AEC/ERDA/DOE and DOE/NRC nuclear air cleaning conferences

    International Nuclear Information System (INIS)

    This document contains a cumulative index to the first through twentieth AEC, ERDA, DOE, and DOE/NRC Nuclear Air Cleaning Conferences and incorporates corrections of errors appearing in prior intermediate indexes

  20. Applicability of the Environmental Relative Moldiness Index for Quantification of Residential Mold Contamination in an Air Pollution Health Effects Study

    OpenAIRE

    Ali Kamal; Janet Burke; Stephen Vesper; Stuart Batterman; Alan Vette; Christopher Godwin; Marina Chavez-Camarena; Gary Norris

    2014-01-01

    The Near-Road Exposures and Effects of Urban Air Pollutants Study (NEXUS) investigated the impact of exposure to traffic-related air pollution on the respiratory health of asthmatic children in Detroit, Michigan. Since indoor mold exposure may also contribute to asthma, floor dust samples were collected in participants homes (n = 112) to assess mold contamination using the Environmental Relative Moldiness Index (ERMI). The repeatability of the ERMI over time, as well as ERMI differences betwe...

  1. Assessment of air pollution tolerance index of some trees in Moradabad city, India.

    Science.gov (United States)

    Tripathi, Anamika; Tiwari, P B; Mahima; Singh, Dharmveer

    2009-07-01

    To see the relative tolerance of the plant species, ten different plant species i.e. Ficus rumphii, Pongamia pinnata, Alstonia scholaris, Holoptelea integrifolia, Saraca indica, Pithecolobium dulcis, Cassia simea, Bauhinia variegata, Azadirachta indica and Grewelia robusta was taken from residential (SI), industrial (SII) and commercial (SIII) area of the city as this florais very much common to the Brass city and is planted on the roadside. The quality of air with respect to SPM, SO2 and NO2 has been also assessed on respective sites to see its effect on biochemical parameters of the leaves i.e. pH, total water content, chlorophyll and ascorbic acid and evaluate the (air pollution tolerance index (APTI) of various plants. It was concluded that Pongamia pinnata 15.8, Pithecolobium dulcis 34.8, Holoptelea integrifolia 55.8 and Saraca indica 52.0 have very high APTI value over control so these are considered as high tolerant tree species, Ficus rumphii 35.7, Azadirachta indica 30.5 and Grewelia robusta 34.3 have slightlymoreAPTI value over control so these are considered as moderately tolerant tree species and Alstonia scholaris 21.5, Cassia simea 6.09 and Bauhinia variegata 18.22 have lessAPTI value than control, so these are sensitive species respectively. One way ANOVA finds the obtained values to be highly significant (p < 0.001) at the industrial site. Thus present findings show that Brass and allied industries are the prominent sources responsible for the elevated level of air pollutants at the industrial site. PMID:20120494

  2. Estimation of Anticipated Performance Index and Air Pollution Tolerance Index and of vegetation around the marble industrial areas of Potwar region: bioindicators of plant pollution response.

    Science.gov (United States)

    Noor, Mehwish Jamil; Sultana, Shazia; Fatima, Sonia; Ahmad, Mushtaq; Zafar, Muhammad; Sarfraz, Maliha; Balkhyour, Masour A; Safi, Sher Zaman; Ashraf, Muhammad Aqeel

    2015-06-01

    Mitigating industrial air pollution is a big challenge, in such scenario screening of plants as a bio monitor is extremely significant. It requires proper selection and screening of sensitive and tolerant plant species which are bio indicator and sink for air pollution. The present study was designed to evaluate the Air Pollution Tolerance Index (APTI) and Anticipated Performance Index (API) of the common flora. Fifteen common plant species from among trees, herb and shrubs i.e. Chenopodium album (Chenopodiaceae), Parthenium hysterophorus (Asteraceae), Amaranthus viridis (Amaranthaceae), Lantana camara (Verbenaceaea), Ziziphus nummulari (Rhamnaceae), Silibum merianum (Asteraceae), Cannabis sativa (Cannabinaceae), Calatropis procera (Asclepediaceae), Ricinus communis (Euphorbiaceae), Melia azadirachta (Meliaceae), Psidium guajava (Myrtaceae), Eucalyptus globules (Myrtaceae), Broussonetia papyrifera (Moraceae), Withania somnifera (Solanaceae) and Sapium sabiferum (Euphorbiaceae) were selected growing frequently in vicinity of Marble industries in Potwar region. APTI and API of selected plant species were analyzed by determining important biochemical parameter i.e. total chlorophyll, ascorbic acid, relative water content and pH etc. Furthermore the selected vegetation was studied for physiological, economic, morphological and biological characteristics. The soil of studied sites was analyzed. It was found that most the selected plant species are sensitive to air pollution. However B. papyrifera, E. globulus and R. communis shows the highest API and therefore recommended for plantation in marble dust pollution stress area. PMID:25503327

  3. Exploring EKC, trends of growth patterns and air pollutants concentration level in Malaysia: A Nemerow Index Approach

    Science.gov (United States)

    Bekhet, Hussain A.; >Tahira Yasmin,

    2013-06-01

    The present study examines an Environmental Kuznets Curve (EKC) hypothesis by analyzing annual data of air pollutants concentartion and per capita GDP as economic indicator over the (1996-2010) period in Malaysia. Nemerow Index Approach (I) used to generate a measures of air pollution. The results show that ambient air quality indicators supports the EKC hypothesis which stated that pollution levels increase as a country develops, but begin to decrease as rising incomes pass beyond a turning poin. Also, the I result is justifying that most pollutants are showing value less than 1.

  4. Exploring EKC, trends of growth patterns and air pollutants concentration level in Malaysia: A Nemerow Index Approach

    International Nuclear Information System (INIS)

    The present study examines an Environmental Kuznets Curve (EKC) hypothesis by analyzing annual data of air pollutants concentartion and per capita GDP as economic indicator over the (1996–2010) period in Malaysia. Nemerow Index Approach (I) used to generate a measures of air pollution. The results show that ambient air quality indicators supports the EKC hypothesis which stated that pollution levels increase as a country develops, but begin to decrease as rising incomes pass beyond a turning poin. Also, the I result is justifying that most pollutants are showing value less than 1.

  5. Effect of Scintillometer Height on Structure Parameter of the Refractive Index of Air Measurements

    Science.gov (United States)

    Gowda, P. H.; Howell, T. A.; Hartogensis, O.; Basu, S.; Scanlon, B. R.

    2009-12-01

    Scintillometers measure amount of scintillations by emitting a beam of light over a horizontal path and expresses as the atmospheric turbulence structure parameter as the refractive index of air (Cn2). Cn2 represents the turbulent strength of the atmosphere and describes the ability of the atmosphere to transport heat and humidity. The main objective of this study was to evaluate the effect of scintillometer height on Cn2 measurements and on the estimation of latent heat fluxes. The study was conducted during the 2009 summer growing season in the USDA-ARS Conservation and Production Research Laboratory (CPRL) at Bushland [350 11' N, 1020 06' W; 1,170 m elevation MSL], Texas. Field experiment consisted of two steps: (1) cross-calibration of scintillometers and (2) measurement of Cn2 at different heights. In the first step, three large aperture scintillometers (LAS) were deployed across two large lysimeter fields with bare soil surfaces. During the 3-week cross-calibration period, all three scintillometers were installed at a 2-m height with a path length of 420 m. Cn2 was monitored at a 1-min interval and averaged for 15-min periods. Cn2 measurements were synchronized with weather station and weighing lysimeter measurements. After the cross-calibration period, scintillometers were installed at 2-, 2.5- and 3-m heights, and Cn2 measurements were continued for another 3-week period. In addition to the Cn2 measurements, net radiation (Rn) and soil heat fluxes (G) were measured in both lysimeter fields. Cn2 values were corrected for inner scale dependence before cross calibration and estimation of sensible heat fluxes. Measurements of wind speed, air temperature, and relative humidity were used with Cn2 data to derive sensible heat fluxes. Latent heat fluxes were estimated as a residual from the energy balance and compared with lysimeter data. Results of cross calibration and effects of scintillometer height on the estimation of latent heat fluxes were reported and discussed.

  6. Daily index of air pollution level; Indice giornaliero della qualita` dell`aria IGQA

    Energy Technology Data Exchange (ETDEWEB)

    Albergamo, C.; Cagnetti, P.; Mammarella, M. C.; Tondo, A. [ENEA, Centro Ricerche Casaccia, Rome (Italy). Dipt. Ambiente

    1997-05-01

    A daily evaluation of pollution level in urban area is the starting point to carry out any proper analysis of pollution data. In this paper an algorithm is stated in order to provide both a method to evaluate pollution level and a direct interpretation of resulting values according to the present law. Hour data, which is taken from surveying points, is previously transformed to daily data and then normalised to standard values. Afterwards, one value per pollutant is obtained as an index of the daily situation for the whole area. The operational choices in the algorithm are made with respect to the present law. The algorithm has been carried out by SAS language as a part of the project called A.T.M.O.S.F.E.R.A. (a decision-support-system developed by ENEA) to give a useful and intuitive instrument to spot critical situations for air pollution. The last part of the paper is an application to Rome data, from January 1992 to December 1996.

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

    International Nuclear Information System (INIS)

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

  8. Development of a health-based air quality index for Canada : public opinion research 2004-05 : final report

    International Nuclear Information System (INIS)

    Canadians rely on an air quality indexes (AQIs) to inform them about air pollution conditions in their communities. However, there is no AQI common to all of Canada, and there is a lack of consistency in the way in which air quality is calculated and reported, as well as in the use of health-based messages. This paper reported findings of a public opinion research survey conducted to gauge Canadians' awareness, perceptions and behavioural responses to air quality, air pollution and AQIs. The aim of the study was to guide the development of health messages to more effectively communicate the AQI to Canadians with respect to the health risks associated with poor air quality. Telephone surveys were conducted immediately following a poor air quality episode to measure the public's awareness and response to these events, as well as residents' general awareness and use of AQIs. A separate research project was then conducted which consisted of in-depth qualitative interviews with 28 individuals recruited from the general population. A comprehensive national telephone survey was then conducted following the summer 2004 'smog season', which focused on the public's awareness of air pollution and AQIs. Results from the first 2 phases of the research were then presented at a workshop comprised of health and environmental communities specializing in air issues in Canada. Focus groups were then held to test public reaction to new AQI communications concepts derived from the research. Results indicated that Canadians widely identify air pollution as a significant environmental problem. However, the information from AQIs had a limited impact in terms of prompting actions to reduce personal exposure. A new type of national AQI for Canada was developed that conveyed information on air quality conditions and their significance. Key features include a 0 to 10 point unbounded scale showing current air quality conditions; a forecast of future conditions; standardized information covering health risks; targeted information for groups most at risk; and recommended activities

  9. Humidity dependence in kerma area product meter used in diagnostic X ray examinations

    International Nuclear Information System (INIS)

    The air-kerma area product, PKA, is a dosimetric quantity that can be directly related to the patient dose and used for risk assessment associated with different x-ray examinations. PKA has the unit Gym2 and can be directly measured by use of a Kerma Area Product (KAP) meter placed in the radiation beam. PKA is the recommended quantity for use in the establishment of diagnostic reference levels (DRLs) for conventional x-ray examinations and is also a good indicator for when threshold doses for deterministic effects are reached in interventional x-ray procedures. Most modern x-ray equipment provides the operator with the total PKA from the examination or procedure. This PKA is either obtained from PKA measurements from a built-in KAP meter or calculated from exposure parameters. To get a reliable estimate of DRLs and the patient dose, it is essential that the PKA measurement is correct. Thus all environmental influences on the KAP meter should be taken into account. These influences can either be corrected for or included in the measurement uncertainty. These have to be considered both in the calibration of the KAP-meters, in the use of the KAP meters and in the determination of DRLs. A KAP meter is an electrometer and a plane parallel ion chamber with an active area of typical 15 cm X 15 cm. The KAP meter usually consist of three plastic plates (PMMA) which is coated with a conducting layer made of indium oxide doped with tin (In2O3:Sn). This coating is used due to its transparency to light. The air layers between the plates (sensitive volume) are open to the air. Thus the readings from the KAP meter have to be corrected for air pressure and temperature as for other ion chambers. It has been assumed that the humidity dependence of the KAP meter is so small that no correction has been necessary. This work will show that KAP meter with PMMA plastic plates coated with In2O3:Sn shows a humidity dependence so large that corrections should be considered. The measurements were performed by carefully controlling the humidity in the laboratory. Between each measurement the humidity was changed with steps of 5 to 10 %RH in the range 20-60 %RH. The measurements were performed two days after the humidity change, so the humidity inside the chamber could stabilise. The setup was as for a substitution calibration with the KAP meter 100 cm from the x- ray source and exposed to a beam limited by a aperture of 5 cm X 5 cm at 95 cm as described in TRS-457. A Capintec PR-30 was used as a monitor chamber. This chamber is made of C-552 and has small humidity dependence. Two KAP-chambers were tested. Both chambers showed the same humidity dependence. The humidity dependence for the chambers was (0.24 ± 0.10) % pr. %RH (k=2). The transmission factor of the chambers showed no humidity dependence. One of the chambers were tested at five different qualities from 40 kV to 150 kV (RQR2, RQR5, RQR8, RQR9, RQR 10). The humidity dependence was the same for all qualities. In an environment with no humidity control the humidity can typically vary from 20 %RH to 80 %RH. According to the results this can lead to about 14 % change in the KAP reading. This is a larger effect than recommended for KAP meters, ± 3.0 %, in the IEC 60580 standard. The observed humidity dependence means that great care have to be take when calibrating and using KAP meter for dose measurements. The humidity effect is not fully understood but it seems that the conducting layer on the PMMA is the origin of the effect

  10. Determination of mass attenuation coefficients, effective atomic and electron numbers, mean free paths and kermas for PbO, barite and some boron ores

    Science.gov (United States)

    Un, A.; Sahin, Y.

    2011-07-01

    The total mass attenuation coefficients, ? m, for PbO, barite, colemanite, tincal and ulexite were determined at 80.1, 302.9, 356.0, 661.7 and 1250.0 keV photon energies by using NaI (Tl) scintillation detector. Effective atomic number, Z eff, effective electron number, N eff, total atomic cross-section, ? t, total electronic cross-section, ? e, mean free path, mfp, and kerma relative to air were determined experimentally and theoretically. The theoretical mass attenuation coefficients were estimated using mixture rule. The calculated values were compared with the experimental values for all samples.

  11. Determination of mass attenuation coefficients, effective atomic and electron numbers, mean free paths and kermas for PbO, barite and some boron ores

    International Nuclear Information System (INIS)

    The total mass attenuation coefficients, ?m, for PbO, barite, colemanite, tincal and ulexite were determined at 80.1, 302.9, 356.0, 661.7 and 1250.0 keV photon energies by using NaI (Tl) scintillation detector. Effective atomic number, Zeff, effective electron number, Neff, total atomic cross-section, ?t, total electronic cross-section, ?e, mean free path, mfp, and kerma relative to air were determined experimentally and theoretically. The theoretical mass attenuation coefficients were estimated using mixture rule. The calculated values were compared with the experimental values for all samples.

  12. Automatic unit for measuring refractive index of air based on Ciddor equation and its verification using direct interferometric measurement method.

    Czech Academy of Sciences Publication Activity Database

    Hucl, Václav; ?ížek, Martin; Hrabina, Jan; Mikel, B?etislav; ?e?ucha, Šimon; Buchta, Zden?k; Jedli?ka, Petr; Lešundák, Adam; Oulehla, Jind?ich; Mr?a, Libor; Šarbort, Martin; Šmíd, Radek; Lazar, Josef; ?íp, Ond?ej

    Bellingham : SPIE, 2013, 878837:1-9. ISBN 978-0-8194-9604-1. [Optical Measurement Systems for Industrial Inspection /8./. Munich (DE), 13.05.2013-16.05.2013] R&D Projects: GA ?R GAP102/10/1813; GA ?R GPP102/11/P819 Institutional support: RVO:68081731 Keywords : refractive index of air * precise measurement * laser interferometer Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  13. Position sensing with suppression of the drift of the refractive index of air for high resolution interferometry.

    Czech Academy of Sciences Publication Activity Database

    Holá, Miroslava; Buchta, Zden?k; ?íp, Ond?ej; Lazar, Josef

    Piscataway : IEEE, 2014. ISBN 978-1-4673-5225-3. [URSI General Assembly and Scientific Symposium (URSI GASS) 2014 /31./. Beijing (CN), 16.08.2014-23.08.2014] R&D Projects: GA TA ?R TA02010711; GA TA ?R TE01020233; GA MŠk(CZ) LO1212; GA MŠk ED0017/01/01 Institutional support: RVO:68081731 Keywords : refractive index of air * interferometry * Edlen formula Subject RIV: BH - Optics, Masers, Lasers

  14. High-accuracy correction of air refractive index by using two-color heterodyne interferometry of optical frequency combs

    International Nuclear Information System (INIS)

    High-accuracy two-color heterodyne interferometry based on fundamental and second harmonic of frequency combs for air refractive index correction is developed. A monitor interferometer as well as a probe interferometer is constructed to compensate the phase noises and drifts, which are caused by introducing the acousto-optic modulators for heterodyne interferometer, to realize high-accuracy measurement of optical distance. A relative stability of 10?10 to the total length for 500 s is achieved in the measurement of an optical path length difference between two wavelengths. In long-term measurements, the interferometric measurement results and the calculations from empirical equation of air refractive indices are in good agreement with a standard deviation of 4.1 × 10?10 throughout the 10 h period. By applying the two-color method, high-accuracy correction of air refractive index with an uncertainty of 8.9 × 10?8 is achieved during 10 h continuous measurements while the total refractive index changes with a range of 2.0 × 10?6. (paper)

  15. 40 CFR Appendix G to Part 58 - Uniform Air Quality Index (AQI) and Daily Reporting

    Science.gov (United States)

    2010-07-01

    ...of public access, or by any other means, including a recorded phone message, a public Internet site, or facsimile transmission...index value as the AQI for O3 . ER27MR08.001 Where: Ip = the index value for pollutantp Cp = the truncated...

  16. A Satellite-Based Multi-Pollutant Index of Global Air Quality

    Science.gov (United States)

    Cooper, Mathew J.; Martin, Randall V.; vanDonkelaar, Aaron; Lamsal, Lok; Brauer, Michael; Brook, Jeffrey R.

    2012-01-01

    Air pollution is a major health hazard that is responsible formillions of annual excess deaths worldwide. Simpleindicators are useful for comparative studies and to asses strends over time. The development of global indicators hasbeen impeded by the lack of ground-based observations in vast regions of the world. Recognition is growing of the need for amultipollutant approach to air quality to better represent human exposure. Here we introduce the prospect of amultipollutant air quality indicator based on observations from satellite remote sensing.

  17. How the consumer confidence index could increase air travel demand forecast accuracy?

    OpenAIRE

    Teyssier, Narjesse

    2012-01-01

    Because of the complex nature of the air transportation industry with continuous changes in the environment, the past records of air traffic forecasters, either using trend extrapolation or causal models or even more sophisticated methods have not produced accurate results. In recent years, the trend has been to develop air travel demand forecasts based on econometric equations, which specify a relationship between passenger traffic and a number of traditional key economic variables. However ...

  18. Energy absorption buildup factors, exposure buildup factors and Kerma for optically stimulated luminescence materials and their tissue equivalence for radiation dosimetry

    International Nuclear Information System (INIS)

    Optically stimulated luminescence (OSL) materials are sensitive dosimetric materials used for precise and accurate dose measurement for low-energy ionizing radiation. Low dose measurement capability with improved sensitivity makes these dosimeters very useful for diagnostic imaging, personnel monitoring and environmental radiation dosimetry. Gamma ray energy absorption buildup factors and exposure build factors were computed for OSL materials using the five-parameter Geometric Progression (G-P) fitting method in the energy range 0.015–15 MeV for penetration depths up to 40 mean free path. The computed energy absorption buildup factor and exposure buildup factor values were studied as a function of penetration depth and incident photon energy. Effective atomic numbers and Kerma relative to air of the selected OSL materials and tissue equivalence were computed and compared with that of water, PMMA and ICRU standard tissues. The buildup factors and kerma relative to air were found dependent upon effective atomic numbers. Buildup factors determined in the present work should be useful in radiation dosimetry, medical diagnostics and therapy, space dosimetry, accident dosimetry and personnel monitoring. - Highlights: • EABF and EBF values of OSL materials have been calculated using G-P fitting method. • Zeff of OSL materials was observed higher than water, PMMA and standard ICRU tissues. • EABF, EBF and Ka were found Zeff dependent. • Ka of BeO roughly independent upon photon energies. • We found BeO the most promising OSL material for clinical and medical dosimetry

  19. Review of the research and application of KERMA factor and DPA cross section

    International Nuclear Information System (INIS)

    The data for recoil atom spectra, KERMA factor and displacement cross sections from neutron-induced reactions are calling increasing interest for applications to the study of radiation damage, calculation of heat generation in reactor, neutron therapy and biological research. PKA spectra sub-working group was recently established in Japanese Nuclear Data Committee as a part of developing JENDL Special Purpose Data Files. Current status of the data and various features of application of the KERMA-related problems were reviewed and discussed at the first meeting of the sub-working group. Present report is a compilation of the items presented at the meeting, covering a brief review of the existing research and the data, method of calculation, the KERMA factor data in neutron therapy, the deduction of KERMA factor of C-12 from neutron reaction measurement and analysis, the data base for radiation damage, the damage simulation calculation, and the method of storaging the evaluated data in ENDF/B-VI format. (author)

  20. The role of air pollution in the relationship between a heat stress index and human mortality in Toronto

    International Nuclear Information System (INIS)

    In this study we considered confounding from air pollutants and chronological variables in the relation between humidex, a summer temperature and humidity index, and nonaccidental mortality, from 1980-1996 in Toronto, Canada. Changes in the risk of death by age group, gender, and combined cardiac-respiratory cause of death were estimated for both 1 deg. C and 50-95th percentile increases in humidex using a generalized additive linear model. With air pollution terms in the models, relative risk (RR) point estimates narrowly exceeded 1.0 for all groups. Humidex effects were most apparent for females (RR=1.006, 95% CI=1.004-1.008 per 1 deg. C humidex and RR=1.089, 95% CI=1.058-1.121 for 50th to 95th percentile humidex). When air pollution was omitted from the model, RR in the 50-95th percentile analysis increased less than 1.71% for all groups except females, for which RR decreased 1.42%. Differences in RR per 1 deg. C humidex were all less than 0.12%. Confidence intervals narrowed slightly for all groups investigated. Heat stress has a statistically significant, yet minimal impact on Toronto populations, and air pollution does appear to have a small, but consistent confounding effect on humidex effect estimates

  1. PLAM - a meteorological pollution index for air quality and its applications in fog-haze forecasts in north China

    Science.gov (United States)

    Yang, Y.; Wang, J.; Gong, S.; Zhang, X.; Wang, H.; Wang, Y.; Wang, J.; Li, D.; Guo, J.

    2015-03-01

    Using surface meteorological observation and high resolution emission data, this paper discusses the application of PLAM/h Index (Parameter Linking Air-quality to Meteorological conditions/haze) in the prediction of large-scale low visibility and fog-haze events. Based on the two-dimensional probability density function diagnosis model for emissions, the study extends the diagnosis and prediction of the meteorological pollution index PLAM to the regional visibility fog-haze intensity. The results show that combining the influence of regular meteorological conditions and emission factors together in the PLAM/h parameterization scheme is very effective in improving the diagnostic identification ability of the fog-haze weather in North China. The correlation coefficients for four seasons (spring, summer, autumn and winter) between PLAM/h and visibility observation are 0.76, 0.80, 0.96 and 0.86 respectively and all their significance levels exceed 0.001, showing the ability of PLAM/h to predict the seasonal changes and differences of fog-haze weather in the North China region. The high-value correlation zones are respectively located in Jing-Jin-Ji (Beijing, Tianjin, Hebei), Bohai Bay rim and the southern Hebei-northern Henan, indicating that the PLAM/h index has relations with the distribution of frequent heavy fog-haze weather in North China and the distribution of emission high-value zone. Comparatively analyzing the heavy fog-haze events and large-scale fine weather processes in winter and summer, it is found that PLAM/h index 24 h forecast is highly correlated to the visibility observation. Therefore, PLAM/h index has better capability of doing identification, analysis and forecasting.

  2. PLAM – a meteorological pollution index for air quality and its applications in fog-haze forecasts in north China

    Directory of Open Access Journals (Sweden)

    Y. Yang

    2015-03-01

    Full Text Available Using surface meteorological observation and high resolution emission data, this paper discusses the application of PLAM/h Index (Parameter Linking Air-quality to Meteorological conditions/haze in the prediction of large-scale low visibility and fog-haze events. Based on the two-dimensional probability density function diagnosis model for emissions, the study extends the diagnosis and prediction of the meteorological pollution index PLAM to the regional visibility fog-haze intensity. The results show that combining the influence of regular meteorological conditions and emission factors together in the PLAM/h parameterization scheme is very effective in improving the diagnostic identification ability of the fog-haze weather in North China. The correlation coefficients for four seasons (spring, summer, autumn and winter between PLAM/h and visibility observation are 0.76, 0.80, 0.96 and 0.86 respectively and all their significance levels exceed 0.001, showing the ability of PLAM/h to predict the seasonal changes and differences of fog-haze weather in the North China region. The high-value correlation zones are respectively located in Jing-Jin-Ji (Beijing, Tianjin, Hebei, Bohai Bay rim and the southern Hebei-northern Henan, indicating that the PLAM/h index has relations with the distribution of frequent heavy fog-haze weather in North China and the distribution of emission high-value zone. Comparatively analyzing the heavy fog-haze events and large-scale fine weather processes in winter and summer, it is found that PLAM/h index 24 h forecast is highly correlated to the visibility observation. Therefore, PLAM/h index has better capability of doing identification, analysis and forecasting.

  3. Evaluation of the Chinese New Air Quality Index (GB3095-2012) : Based on Comparison with the US AQI System and the WHO AQGs

    OpenAIRE

    Gao, Fanyu

    2013-01-01

    The “PM2.5 issue” was the tipping point for China’s clean air movement last year and the incentive for implementation of the new Air Quality Index (GB3095-2012). It is necessary to carry out an evaluation of the Chinese new AQI system based on comparison with developed countries and improve the system afterwards. The study evaluates the Chinese new Air Quality Index through comparison with the EPA AQI system and with the WHO AQGs as reference. The six mutual indicators have been selected, ...

  4. Interferometry with direct compensation of fluctuations of refractive index of air.

    Czech Academy of Sciences Publication Activity Database

    Lazar, Josef; ?ížek, Martin; Hrabina, Jan; Buchta, Zden?k

    Paris : LNE, 2011, s. 66-68. [Workshop on Metrological Atomic Force Microscope Instrumentation. Trappes (FR), 07.02.2011-09.02.2011] Institutional research plan: CEZ:AV0Z20650511 Keywords : nanometrology * interferometry * refractive index Subject RIV: BH - Optics, Masers, Lasers

  5. Air

    Science.gov (United States)

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

  6. Association between indoor air pollutant exposure and blood pressure and heart rate in subjects according to body mass index.

    Science.gov (United States)

    Jung, Chien-Cheng; Su, Huey-Jen; Liang, Hsiu-Hao

    2016-01-01

    This study investigates the effects of high body mass index (BMI) of subjects on individual who exhibited high cardiovascular disease indexes with blood pressure (BP) and heart rate (HR) when exposed to high levels of indoor air pollutants. We collected 115 office workers, and measured their systolic blood pressure (SBP), diastolic blood pressure (DBP) and HR at the end of the workday. The subjects were divided into three groups according to BMI: 18-24 (normal weight), 24-27 (overweight) and >27 (obese). This study also measured the levels of carbon dioxide (CO2), total volatile organic compounds (TVOC), particulate matter with an aerodynamic diameter less than 2.5?m (PM2.5), as well as the bacteria and fungi in the subjects' work-places. The pollutant effects were divided by median. Two-way analysis of variance (ANOVA) was used to analyze the health effects of indoor air pollution exposure according to BMI. Our study showed that higher levels of SBP, DBP and HR occurred in subjects who were overweight or obese as compared to those with normal weight. Moreover, there was higher level of SBP in subjects who were overweight or obese when they were exposed to higher levels of TVOC and fungi (p<0.05). We also found higher value for DBP and HR with increasing BMI to be associated with exposure to higher TVOC levels. This study suggests that individuals with higher BMI have higher cardiovascular disease risk when they are exposed to poor indoor air quality (IAQ), and specifically in terms of TVOC. PMID:26363400

  7. Measurement of the nonlinear refractive index of air constituents at mid-infrared wavelengths

    CERN Document Server

    Zahedpour, S; Milchberg, H M

    2015-01-01

    We measure the nonlinear refractive index coefficients in N$_2$, O$_2$ and Ar from visible through mid-infrared wavelengths (\\lambda = 0.4 - 2.4 {\\mu}m). The wavelengths investigated correspond to transparency windows in the atmosphere. Good agreement is found with theoretical models of $\\chi^{(3)}$. Our results are essential for accurately simulating the propagation of ultrashort mid-IR pulses in the atmosphere.

  8. Air Pollution Tolerance Index (APTI) of some tree species growing near rail roads of Madurai, Tamil Nadu (India).

    Science.gov (United States)

    Thambavani, D Sarala; Kamala, C

    2010-10-01

    Biological monitoring and assessment studies due to urban--rail road pollutants were carried out using Air Pollution Tolerance Index (APTI) of plants. Four plant (leaf) parameters--namely ascorbic acid, total chlorophyll, relative water content and leaf extract pH were combined together in a formulation signifying the APTI of plants. APTI was calculated for five different species such as Azadirachta indica, Delonix regia, Ficus religiosa, Pongamia pinnata and Polyalthia longifolia growing in two different areas, i.e. control area and along the railway track of Madurai, Tamil Nadu (India). The control site was selected in the college campus. None of the four plant parameters indicated a consistent response to pollutants. In the present study, Delonix regia and Pongamia pinnata lost the tolerance towards air pollutants and became more sensitive, but Azadirachta indica, Ficus religiosa, and Polyalthia longifolia indicated high APTI values over control area and hence considered as tolerant species. The APTI of plants showed a marked gradation as the pollutant load decreased from rail road to control area. The APTI can be used as a good indicator of impact of the air pollution on plants. PMID:22312796

  9. Precision positioning with suppression of the influence of refractive index of air.

    Czech Academy of Sciences Publication Activity Database

    Holá, Miroslava; Hrabina, Jan; Oulehla, Jind?ich; ?ížek, Martin; Mikel, B?etislav; ?e?ucha, Šimon; Buchta, Zden?k; ?íp, Ond?ej; Lazar, Josef

    Bellingham : SPIE, 2013, 878831:1-7. ISBN 978-0-8194-9604-1. [Optical Measurement Systems for Industrial Inspection /8./. Munich (DE), 13.05.2013-16.05.2013] R&D Projects: GA ?R GA102/09/1276; GA ?R GPP102/11/P820; GA TA ?R TA02010711; GA TA ?R TE01020233; GA MŠk ED0017/01/01 Institutional support: RVO:68081731 Keywords : nanometrology * refractometry * interferometry * refractive index * nanoscale Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  10. Studies on mass attenuation coefficient, mass energy absorption coefficient and kerma of some vitamins

    International Nuclear Information System (INIS)

    Highlights: ? Kerma is essential for nuclear medicine, diagnostics and radiation dosimeter. ? The values of ?m and ?e/? depends on the photon energy and chemical content of vitamins. ? New experiments should be performed to study physical parameters of biomolecules. -- Abstract: The mass attenuation coefficients for some vitamins (retinol, beta-carotene, thiamine, riboflavin, niacinamide, pantothenic acid, pyridoxine, biotin, folic acid, cyanocobalamin, ascorbic acid, cholecalciferol, alpha-tocopherol, ketamine, hesperidin) were determined experimentally and theoretically at 356.61, 661.66, 1250 and 1408.01 keV photon energies by using a NaI(Tl) scintillation detector. Also, the mass energy absorption coefficients and kerma have been calculated. The calculated values were compared with the semi-empirical values for vitamins.

  11. A simple device for the measurement of kerma based on commercial PIN photo diodes.

    Czech Academy of Sciences Publication Activity Database

    Kushpil, Vasilij; Kushpil, Svetlana; Hu?a, Zden?k

    Cedex : EDP Sciences, 2012, s. 1-9. ISBN 978-88-7438-069-5. ISSN 2100-014X. [International Conference on Environmental Radioactivity - New Frontiers and Developments. ?ím (IT), 25.10.2010-27.10.2010] R&D Projects: GA MŠk LC07048 Institutional support: RVO:61389005 Keywords : PIN diode * kerma measurement Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders

  12. High NDVI and Potential Canopy Photosynthesis of South American Subtropical Forests despite Seasonal Changes in Leaf Area Index and Air Temperature

    OpenAIRE

    Piedad M. Cristiano; Nora Madanes; Paula I. Campanello; Débora di Francescantonio; Sabrina A. Rodríguez; Yong-Jiang Zhang; Laureano Oliva Carrasco; Guillermo Goldstein

    2014-01-01

    The canopy photosynthesis and carbon balance of the subtropical forests are not well studied compared to temperate and tropical forest ecosystems. The main objective of this study was to assess the seasonal dynamics of Normalized Difference Vegetation Index (NDVI) and potential canopy photosynthesis in relation to seasonal changes in leaf area index (LAI), chlorophyll concentration, and air temperatures of NE Argentina subtropical forests throughout the year. We included in the analysis sever...

  13. Status of Obesity in Terms of Body Mass Index among Indian Air Force Personnel

    OpenAIRE

    L Robert Varte; Majumdar, D; Shweta Rawat; Inderjeet Singh

    2011-01-01

    Introduction: This paper investigates the prevalence of obesity (BMI >30 kg/m2) among five geographical groups of Indian Air Force personnel of different age. Purpose of study: To observe the status of obesity among IAF and see whether there is age-wise and regional difference in obesity among the different geographical groups. Results: Gradual increase in mean BMI is seen as age of the population increases. There is an overall marked increase in BMI level among all the three age groups for a...

  14. Studies on effective atomic number, electron density and kerma for some fatty acids and carbohydrates

    DEFF Research Database (Denmark)

    Manohara, S.R.; Hanagodimath, S.M.

    2008-01-01

    The effective atomic number, Z(eff), the effective electron density, N-el, and kerma have been calculated for some fatty acids and carbohydrates for photon interaction in the extended energy range from 1 keV to 100 GeV using an accurate database of photon-interaction cross sections and the WinXCom program. The significant variation of Z(eff) and N-el is due to the variations in the dominance of different interaction processes in different energy regions. The maximum values of Z(eff) and N-el are found in the low-energy range, where photoelectric absorption is the main interaction process. The minimum values of Z(eff) and N-el are found at intermediate energies, typically 0.05 MeV kerma than fatty acids in the low-energy region, where photoelectric absorption dominates. In contrast, fatty acids have a larger kerma than carbohydrates in the MeV range, where Compton scattering is the main interaction process.

  15. Spectral index of high-energy cosmic rays by the Compton-Getting effect at solar time frame with the Tibet air shower array

    International Nuclear Information System (INIS)

    We report on the spectral index of cosmic rays around 10 TeV energy region obtained by observation of the Compton-Getting anisotropy due to the terrestrial orbital motion around the Sun with the Tibet III air shower array during the period from 1999 to 2005. The spectral index has turned out to be 2.99±0.54, which is consistent with 2.74 by the direct energy spectrum measurement. This method is a new approach to measure the spectral index and is complementary to the conventional energy spectrum measurement

  16. Air ion and pollution index variation for indoor and outdoor atmosphere at rural station Ramanandnagar (17° 4?N, 74° 25?) India

    Indian Academy of Sciences (India)

    S D Pawar

    2013-02-01

    In the present study, the observation of indoor air ion concentration at a rural site has been carried out for the first time. These indoor observations are compared with outdoor air ion concentration. Net charge can be introduced into the atmosphere by processes such as combustion, rainfall and ultraviolet radiation. As compared to indoors, average air ions of both the polarities at outdoors are higher. Moreover, the air ion concentrations, experience large fluctuations during daytime, as compared to nighttime values. Positive and negative air ion concentrations are lower and uniform throughout the night both for indoor and outdoor conditions. Pollution index is more or less unity for outdoors in all-the-time period, which is good for human health. Due to limited sources of air ions indoors, it is observed that pollution index decreases from 00:00–02:00 hours and minimum is reached during 12:00–14:00 hours for indoors. During 00:00–02:00 hours, the indoor pollution index is 1.55, which is very harmful to human health.

  17. Determination of mass attenuation coefficients, effective atomic and electron numbers, mean free paths and kermas for PbO, barite and some boron ores

    Energy Technology Data Exchange (ETDEWEB)

    Un, A., E-mail: ademun25@yahoo.com [Agri Ibrahim Cecen University, Faculty of Arts and Sciences, Department of Physics, 04100 Agri (Turkey); Sahin, Y. [Atatuerk University, Faculty of Sciences, Department of Physics, 25240 Erzurum (Turkey)

    2011-07-01

    The total mass attenuation coefficients, {mu}{sub m}, for PbO, barite, colemanite, tincal and ulexite were determined at 80.1, 302.9, 356.0, 661.7 and 1250.0 keV photon energies by using NaI (Tl) scintillation detector. Effective atomic number, Z{sub eff}, effective electron number, N{sub eff}, total atomic cross-section, {sigma}{sub t}, total electronic cross-section, {sigma}{sub e}, mean free path, mfp, and kerma relative to air were determined experimentally and theoretically. The theoretical mass attenuation coefficients were estimated using mixture rule. The calculated values were compared with the experimental values for all samples.

  18. Improving Neural Network Prediction Accuracy for PM10 Individual Air Quality Index Pollution Levels.

    Science.gov (United States)

    Feng, Qi; Wu, Shengjun; Du, Yun; Xue, Huaiping; Xiao, Fei; Ban, Xuan; Li, Xiaodong

    2013-12-01

    Fugitive dust deriving from construction sites is a serious local source of particulate matter (PM) that leads to air pollution in cities undergoing rapid urbanization in China. In spite of this fact, no study has yet been published relating to prediction of high levels of PM with diameters neural network models (multilayer perceptron, Elman, and support vector machine) in predicting daily PM10 IAQI one day in advance. To obtain acceptable forecasting accuracy, measured time series data were decomposed into wavelet representations and wavelet coefficients were predicted. Effectiveness of these forecasters were tested using a time series recorded between January 1, 2005, and December 31, 2011, at six monitoring stations situated within the urban area of the city of Wuhan, China. Experimental trials showed that the improved models provided low root mean square error values and mean absolute error values in comparison to the original models. In addition, these improved models resulted in higher values of coefficients of determination and AHPC (the accuracy rate of high PM10 IAQI caused by nearby construction activity) compared to the original models when predicting high PM10 IAQI levels attributable to fugitive dust from nearby construction sites. PMID:24381481

  19. Spatial and temporal analysis of Air Pollution Index and its timescale-dependent relationship with meteorological factors in Guangzhou, China, 2001–2011

    International Nuclear Information System (INIS)

    There is an increasing interest in spatial and temporal variation of air pollution and its association with weather conditions. We presented the spatial and temporal variation of Air Pollution Index (API) and examined the associations between API and meteorological factors during 2001–2011 in Guangzhou, China. A Seasonal-Trend Decomposition Procedure Based on Loess (STL) was used to decompose API. Wavelet analyses were performed to examine the relationships between API and several meteorological factors. Air quality has improved since 2005. APIs were highly correlated among five monitoring stations, and there were substantial temporal variations. Timescale-dependent relationships were found between API and a variety of meteorological factors. Temperature, relative humidity, precipitation and wind speed were negatively correlated with API, while diurnal temperature range and atmospheric pressure were positively correlated with API in the annual cycle. Our findings should be taken into account when determining air quality forecasts and pollution control measures. - Highlights: • Air pollution is still serious in Guangzhou, China. • Air Pollution Index was associated with a variety of meteorological parameters. • The temporal relationships were timescale-dependent. • The findings should be taken into account in air quality forecasts and pollution control. - Spatial and temporal variation of API and its timescale-dependent relationship with meteorological factors in Guangzhou were demonstrated

  20. Use of Segregation Indices, Townsend Index, and Air Toxics Data to Assess Lifetime Cancer Risk Disparities in Metropolitan Charleston, South Carolina, USA

    Directory of Open Access Journals (Sweden)

    LaShanta J. Rice

    2014-05-01

    Full Text Available Background: Studies have demonstrated a relationship between segregation and level of education, occupational opportunities, and risk behaviors, yet a paucity of research has elucidated the association between racial residential segregation, socioeconomic deprivation, and lifetime cancer risk. Objectives: We examined estimated lifetime cancer risk from air toxics by racial composition, segregation, and deprivation in census tracts in Metropolitan Charleston. Methods: Segregation indices were used to measure the distribution of groups of people from different races within neighborhoods. The Townsend Index was used to measure economic deprivation in the study area. Poisson multivariate regressions were applied to assess the association of lifetime cancer risk with segregation indices and Townsend Index along with several sociodemographic measures. Results: Lifetime cancer risk from all pollution sources was 28 persons/million for half of the census tracts in Metropolitan Charleston. Isolation Index and Townsend Index both showed significant correlation with lifetime cancer risk from different sources. This significance still holds after adjusting for other sociodemographic measures in a Poisson regression, and these two indices have stronger effect on lifetime cancer risk compared to the effects of sociodemographic measures. Conclusions: We found that material deprivation, measured by the Townsend Index and segregation measured by the Isolation index, introduced high impact on lifetime cancer risk by air toxics at the census tract level.

  1. The photon fluence non-uniformity correction for air kerma near Cs-137 brachytherapy sources

    Science.gov (United States)

    Rodríguez, M. L.; de Almeida, C. E.

    2004-05-01

    The use of brachytherapy sources in radiation oncology requires their proper calibration to guarantee the correctness of the dose delivered to the treatment volume of a patient. One of the elements to take into account in the dose calculation formalism is the non-uniformity of the photon fluence due to the beam divergence that causes a steep dose gradient near the source. The correction factors for this phenomenon have been usually evaluated by the two theories available, both of which were conceived only for point sources. This work presents the Monte Carlo assessment of the non-uniformity correction factors for a Cs-137 linear source and a Farmer-type ionization chamber. The results have clearly demonstrated that for linear sources there are some important differences among the values obtained from different calculation models, especially at short distances from the source. The use of experimental values for each specific source geometry is recommended in order to assess the non-uniformity factors for linear sources in clinical situations that require special dose calculations or when the correctness of treatment planning software is verified during the acceptance tests.

  2. Doses monitoring in radiology: calibration of air kerma-area product (PKA meters

    Directory of Open Access Journals (Sweden)

    Ricardo Andrade Terini

    2013-12-01

    Full Text Available Objective The authors have sought to study the calibration of a clinical PKA meter (Diamentor E2 and a calibrator for clinical meters (PDC in the Laboratory of Ionizing Radiation Metrology at Instituto de Energia e Ambiente - Universidade de São Paulo. Materials and Methods Different qualities of both incident and transmitted beams were utilized in conditions similar to a clinical setting, analyzing the influence from the reference dosimeter, from the distance between meters, from the filtration and from the average beam energy. Calibrations were performed directly against a standard 30 cm3 cylindrical chamber or a parallel-plate monitor chamber, and indirectly against the PDC meter. Results The lowest energy dependence was observed for transmitted beams. The cross calibration between the Diamentor E2 and the PDC meters, and the PDC presented the greatest propagation of uncertainties. Conclusion The calibration coefficient of the PDC meter showed to be more stable with voltage, while the Diamentor E2 calibration coefficient was more variable. On the other hand, the PDC meter presented greater uncertainty in readings (5.0% than with the use of the monitor chamber (3.5% as a reference.

  3. Calibration of dosimeters used in diagnostic radiology in terms of air kerma rate

    International Nuclear Information System (INIS)

    This study was performed to determine IEC reference radiation beam quality for calibrating dosimeters used in diagnostic radiology. Additional filtration required to establish certain IEC quality was estimated from beam transmission measurements using Al absorbers. The experiment was carried out using medical x-ray equipment at Neelain Medical Center, Khartoum. The required added filtration thickness required to establish RQA quality was estimated according to the the method described in the IEC standard. The required filtration was estimated for each of radiation quality (40, 60, 80, 100, 120,) kV. Result showed the maximum deviation of 2.3%, for the half value-layers, which complied with the standard requirement of 3%, the additional filtration required for the RQA qualities was found to as follows: 1.2 mmAL (RQA2, 40 kV), 11.0 mmAL (RQA3, 60 kV), 20.7 mmAL ( RQA4, 80 kV), 29.5 mmAL (RQA5, 100 kV) and 33.0 mmAL (AQA6, 120 kV), those qualities recommended to be applied to calibration of the diagnostic radiology measurements instruments in Sudan.(Author)

  4. Verification of traceability and backscattering in surface entrance air kerma measurements with detector type ionizing chamber

    International Nuclear Information System (INIS)

    Measurements of doses in radiology services by ionizing chambers are easier than those made by TLD, however the protocols for measurements differ regarding the calibration. The objectives were to verify the traceability in the measures of ESAK corrected by the inverse square law, due to the difference in position between the source and IC and the influence of the backscattered radiation in bringing the detector to the table. Was defined a procedure practiced by the radiological services and designed experimental arrangements for the same technique. Was noted that the approximation of the detector to the table generated a significant backscattered. (author)

  5. Doses monitoring in radiology: calibration of air kerma-area product (PKA) meters / Monitoração de doses em radiologia: a calibração de medidores do produto kerma-área (PKA)

    Scientific Electronic Library Online (English)

    Ricardo Andrade, Terini; Maria Carolina de Santana, Campelo; Jose Neres de, Almeida Jr.; Silvio Bruni, Herdade; Marco Aurelio Guedes, Pereira.

    2013-12-01

    Full Text Available Objective The authors have sought to study the calibration of a clinical PKA meter (Diamentor E2) and a calibrator for clinical meters (PDC) in the Laboratory of Ionizing Radiation Metrology at Instituto de Energia e Ambiente - Universidade de São Paulo. Materials and Methods Different qualities [...] of both incident and transmitted beams were utilized in conditions similar to a clinical setting, analyzing the influence from the reference dosimeter, from the distance between meters, from the filtration and from the average beam energy. Calibrations were performed directly against a standard 30 cm3 cylindrical chamber or a parallel-plate monitor chamber, and indirectly against the PDC meter. Results The lowest energy dependence was observed for transmitted beams. The cross calibration between the Diamentor E2 and the PDC meters, and the PDC presented the greatest propagation of uncertainties. Conclusion The calibration coefficient of the PDC meter showed to be more stable with voltage, while the Diamentor E2 calibration coefficient was more variable. On the other hand, the PDC meter presented greater uncertainty in readings (5.0%) than with the use of the monitor chamber (3.5%) as a reference.

  6. Importance of the neutrons kerma coefficient in the planning of Brachytherapy treatments with Cf-252 sources

    International Nuclear Information System (INIS)

    The Cf-252 is a fast neutrons emitting radioisotope by spontaneous fission that can be used as sealed source in medicine applications, industry and research. Commercially its offer sources of different sizes, compact and with a fast neutrons emission of the order of 106 n/s-?g and an energy spectra that presents respectively maxim and average energy in 2.1 MeV and 0.7 MeV. In medicine new applications are being developed for the treatment of patient with hypoxic and voluminous tumors, where the therapy with photons has not given positive results, as well as for the protocols of therapy treatment by boron neutron capture, where very small sources of Cf-252 will be used with the interstitial brachytherapy technique of high and low dose rate. In this work an analysis of how the small differences that exist in the elementary composition of 4 wicked tumors, 4 ICRU healthy tissues and 3 substitute materials of ICRU tissue used in dosimetry are presented, its generate changes in the neutrons kerma coefficient in function of the energy and consequently in the absorbed dose in the interval of 11 eV to 29 MeV. These differences can produce maximum variations of the neutron kerma coefficients ratio for En > 1 keV of the one: 15% tumor/ICRU guest healthy tissue, 12% ICRU tumor/muscle, 12% ICRU healthy tissues ICRU/ICRU muscle, 22% substitutes tissue/tumor and 22% ICRU substitutes tissue/muscle. Also, it was found that the average value of the neutrons kerma coefficient for the 4 wicked tumors is from 6% to 7% smaller that the average value for the soft tissue in the interval energy of interest for therapy with fast neutrons with En > 1 MeV. These results have a special importance during the planning process of brachytherapy treatments with sources of 252Cf, to optimize and to individualize the patients treatments. (Author)

  7. The variability in kerma output and radiation quality of medical diagnostic x-ray units

    International Nuclear Information System (INIS)

    The use of diagnostic x-ray tubes results in an increased roughness of the anode surface. This effect of tube ageing increases the inherent filtration of the x-ray tube, hereby reducing kerma output and changing radiation quality. To study this effect, used rotating anodes were collected; the surface profiles and surface roughness of 8 focal tracks were determined. The surface profiles were then used to calculate x-ray spectra using a computer code. The results indicate that an increased roughness induces an additional filtration in the tungsten anode. The roughest surface (Ra=5.22 ?m) yields a mean additional absorber thickness in direction of the x-ray beam of about 18 ?m with a corresponding loss in kerma output of about 30 % at 70 kV. The effects on mean photon energy and HVL are rather small but highest around 70 kV and lowest at 140 kV. This is due to the K-edge in the attenuation coefficients of tungsten at 69.5 keV. To study the influence of tube ageing on beam quality with clinical x-ray units, kerma measurements were made for 19 samples as to determine attenuation curves. A fit method for the determination of total filtration including the effects of anode surface deterioration was devised. The thicknesses of the tungsten layers obtained using this method vary from 2.43 ?m to 11.89 ?m with an associated surface roughness Ra from 1.5 to 4.5 ?m corresponding very well to the thicknesses of the additional absorbing layers determined for rough anodes. A determination of additional filtration in terms of an equivalent aluminium filter gave thicknesses from 0.34 to 1.72 mm aluminium. The results showed that the effects of tube ageing on the x-rays could be described by an additional filtration of aluminium. (author)

  8. Effective atomic number, electron density and kerma of gamma radiation for oxides of lanthanides

    Indian Academy of Sciences (India)

    R S Niranjan; B Rudraswamy; N Dhananjaya

    2012-03-01

    An attempt has been made to estimate the effective atomic number, electron density (0.001 to 10$^5$ MeV) and kerma (0.001 to 20 MeV) of gamma radiation for a wide range of oxides of lanthanides using mass attenuation coef?cient from WinXCom and mass energy absorption coef?cient from Hubbell and Seltzer. The values of these parameters have been found to change with energy for different oxides of lanthanides. The lanthanide oxides ?nd remarkable applications in the ?eld of medicine, biology, nuclear engineering and space technology. Nano-oxides of lanthanide ?nd applications in display and lighting industry.

  9. The smart electronic unit for precise measurement of refractive index of air in a nano-positioning stage for scanning probe microscopy (SPM).

    Czech Academy of Sciences Publication Activity Database

    Hucl, Václav; ?ížek, Martin; Buchta, Zden?k; Mikel, B?etislav; Lazar, Josef; ?íp, Ond?ej

    Ostrava : TANGER Ltd, 2012, s. 817-821. ISBN 978-80-87294-32-1. [NANOCON 2012. International Conference /4./. Brno (CZ), 23.10.2012-25.10.2012] R&D Projects: GA MPO FR-TI2/705; GA MPO FR-TI1/241; GA ?R GAP102/10/1813 Institutional support: RVO:68081731 Keywords : refractive index of air * precise measurement * laser interferometer Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  10. Scattering study at free air ionization chamber diaphragm

    International Nuclear Information System (INIS)

    The maim of this work consisted in the assessment of the correction factor for air kerma, due to scattered radiation in the diaphragm of the free-air ionization chamber model 481. LNMRl measurements were made to acquire x-ray spectra corresponding to the Qualities RQR-M, described in IEC 61627 standards (2005). These spectra were used as input data in the MC simulations. The operational range of energy spectra provide up to 35 keV. This energy range is typically used in diagnostic radiology, although there is not primary standard for air kerma. The determination of this factor is a fundamental process in the primary standardization of the air kerma. These factors were obtained by computer simulation using the Penelope code. The results are kRQR-M1=0,9946, kRQR-M2=0,9932, kRQR-M3=0,9978 and kRQR-M4=0,9885; with uncertainties of 0,007 and coverage factor equal to 2. lt can be concluded that, with respect to the diaphragm, the chamber can be used in the primary standard of air kerma. (author)

  11. Tissue kerma vs distance relationships for initial nuclear radiation from the atomic devices detonated over Hiroshima and Nagasaki

    International Nuclear Information System (INIS)

    Initial nuclear radiation is comprised of prompt neutrons and prompt primary gammas from an exploding nuclear device, prompt secondary gammas produced by neutron interactions in the environment, and delayed neutrons and delayed fission-product gammas from the fireball formed after the nuclear device explodes. These various components must all be considered in establishing tissue kerma vs distance relationships which describe the decrease of initial nuclear radiation with distance in Hiroshima and in Nagasaki. The tissue kerma at ground evel from delayed fission-product gammas and delayed neutrons was investigated using the NUIDEA code developed by Science Applications, Inc. This code incorporates very detailed models which can take into account such features as the rise of the fireball, the rapid radioactive decay of fission products in it, and the perturbation of the atmosphere by the explosion. Tissue kerma vs distance relationships obtained by summing results of these current state-of-the-art calculations will be discussed. Our results clearly show that the prompt secondary gammas and delayed fission-product gammas are the dominant components of total tissue kerma from initial nuclear radiation in the cases of the atomic (or pure-fission) devices detonated over Hiroshima and Nagasaki

  12. Human Use Index (Future)

    Data.gov (United States)

    U.S. Environmental Protection Agency — Human land uses may have major impacts on ecosystems, affecting biodiversity, habitat, air and water quality. The human use index (also known as U-index) is the...

  13. Human Use Index

    Data.gov (United States)

    U.S. Environmental Protection Agency — Human land uses may have major impacts on ecosystems, affecting biodiversity, habitat, air and water quality. The human use index (also known as U-index) is the...

  14. Evaluation of skin entry kerma in radiological examinations at the Hospital de Clinicas, Parana, Brazil

    International Nuclear Information System (INIS)

    This paper evaluates the skin entry dose of pediatric and adults patients when submitted to radiological examinations at the Hospital de Clinicas do Parana, Brazil, as part integrate of the data assessment of International Atomic Energy Agency (IAEA) for Latin America. It was performed measurements of dose for evaluation of skin entry kerma in pediatric patients in thorax AP/PA examinations, adults of thorax in AP/PA, cranio caudal mammography and median lateral and patients of computerized tomography in examination of head, thorax and abdomen. The obtained data demonstrate the necessity of verification of diagnostic analysis standards. The great value amplitudes demonstrate the incompatibility of examination executions with those recommended by the literature. The dose values presented partially inside the range recommended and the other over the expected for the due examination when compared with the literature

  15. Evaluation of Kerma rate in the skin entrance in interventional procedures guided by fluoroscopy

    International Nuclear Information System (INIS)

    Interventional therapeutic procedures guided by fluoroscopy are responsible for delayed exposure to radiation of professionals and patients. The technology employed on generation of the pulsed fluoroscopy can be an important tool of protection used for reducing the exposure time. It generates constant width and varied frequency pulse or width pulse or varied frequency for a constant frequency. The typical doses into the skin and its relationship with the quality of the images in the various technical and operational conditions should be known by the professionals so that they can optimize them. Generated radiation doses were evaluated using the Toshiba Infinitix equipment used in invasive cardiology procedures and electrophysiological studies through the Kerma rate at the entrance of the patient's skin measured throughout the year of 2004. With these information shall be set out the criteria for the decision of the technical-operational conditions that allow minimizing of dose

  16. Applicability of the Environmental Relative Moldiness Index for Quantification of Residential Mold Contamination in an Air Pollution Health Effects Study

    Science.gov (United States)

    As part of the Near-Road Exposures and Effects of Urban Air Pollutants Study (NEXUS) investigating the respiratory health impacts of traffic-related air pollutants on asthmatic children in Detroit, Michigan, residential dust samples were collected to quantify mold exposure. Sett...

  17. 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.)

  18. Application of the quality index methodology for dosimetric verification of build-up effect beyond air-tissue interface in treatment planning system algorithms

    International Nuclear Information System (INIS)

    We have designed a simple benchmark test for the user of a treatment planning system to check the calculation algorithm's ability to model the build up effect beyond an air/tissue interface. The expected result is expressed as an inhomogeneity correction factor CF derived from measurements and from Monte Carlo calculations for a full range of photon beam qualities. The linear regression lines obtained from plotting CF as a function of beam quality index form the basis for a quantitative check of the algorithm performance

  19. Uncontrolled combustion of shredded tires in a landfill - Part 2: Population exposure, public health response, and an air quality index for urban fires

    Science.gov (United States)

    Singh, Ashish; Spak, Scott N.; Stone, Elizabeth A.; Downard, Jared; Bullard, Robert L.; Pooley, Mark; Kostle, Pamela A.; Mainprize, Matthew W.; Wichman, Michael D.; Peters, Thomas M.; Beardsley, Douglas; Stanier, Charles O.

    2015-03-01

    The Iowa City Landfill in eastern Iowa, United States, experienced a fire lasting 18 days in 2012, in which a drainage layer of over 1 million shredded tires burned, generating smoke that impacted the surrounding metropolitan area of 130,000 people. This emergency required air monitoring, risk assessment, dispersion modeling, and public notification. This paper quantifies the impact of the fire on local air quality and proposes a monitoring approach and an air quality index (AQI) for use in future tire fires and other urban fires. Individual fire pollutants are ranked for acute and cancer relative risks using hazard ratios, with the highest acute hazard ratios attributed to SO2, particulate matter, and aldehydes. Using a dispersion model in conjunction with the new AQI, we estimate that smoke concentrations reached unhealthy outdoor levels for sensitive groups out to distances of 3.1 km and 18 km at 24-h and 1-h average times, respectively. Modeled and measured concentrations of PM2.5 from smoke and other compounds such as VOCs and benzo[a]pyrene are presented at a range of distances and averaging times, and the corresponding cancer risks are discussed. Through reflection on the air quality response to the event, consideration of cancer and acute risks, and comparison to other tire fires, we recommend that all landfills with shredded tire liners plan for hazmat fire emergencies. A companion paper presents emission factors and detailed smoke characterization.

  20. Patient Specific Kerma Area Product as an Exposure Estimator in Computed Tomography: The Concept and Typical Values

    International Nuclear Information System (INIS)

    Monitoring of exposure levels in computed tomography is important from the radiation safety point of view. In this paper, the concept suggested by Huda of using the patient specific kerma area product as an exposure estimator is extended by providing both a rigorous definition of this quantity and a method for its evaluation. The method was demonstrated on an axial scan of the standard CT dosimetry head phantom taken with a Siemens Somatom Open CT scanner. The resulting patient specific kerma area product was 0.25 Gy cm2 for the X ray tube voltage of 120 kV, tube current of 100 mA, scanning time of 1 s, and beam width at the isocentre of 1.2 cm. To implement this method, the CT scanner must be equipped with a KAP meter, and the calculation procedure must be added to the scanner's software. Alternatively, the patient specific kerma area product can be calculated by the CT scanner without using a KAP meter. In this case, however, the extra safety feature provided by the direct monitoring of the X ray beam by the KAP meter is lost. (author)

  1. ZZ KAOS/LIB-V, Kerma Factors, Nuclear Response Function Library for Fission, Fusion

    International Nuclear Information System (INIS)

    Description of program or function: Format: FIDO; Number of groups: 174 neutron groups; Nuclides: H, He, Li, Be, B, C, N, O, F, Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Hf, Ta, W, Pb, Bi, Th, Pa, U, Np, Pu, Am. Origin: ENDF/B-V, JENDL-2; Weighting spectrum: VITAMIN-E weighting function. The library includes neutron kerma factors, gas production, tritium breeding cross sections, and all important reaction cross sections for a large number of materials of interest in fission and fusion systems. The library was generated with the KAOS-V code (PSR-306) employing basic nuclear data from ENDF/B-V. Auxiliary nuclear data bases, such as the Japanese library JENDL-2, were used as a source of isotopic cross sections when these data are not provided in ENDF/B-V files for a natural element. KAOS/LIB-V employs the VITAMIN-E weighting function and energy group structure of 174 neutron groups. The library is designed for fusion and fission applications

  2. Comments on 'Direct determination of kerma for a d(48.5)+Be therapy beam'

    International Nuclear Information System (INIS)

    In their paper, the authors comment on the differences between their results and ours, which we obtained in a p(62 MeV)+Be beam using Al and Al2O3 with a single anode wire. However, rather than focusing, as they did, on the differences between these two sets of measurements, it would, perhaps, be more appropriate to highlight the similarities, since these are, to the best of my knowledge, the only two published datasets for this kind of oxygen and carbon in fast neutron therapy beams. Comparing their figure 4 with our figure 8, both sets of measurements show an increased proton dose component for oxygen compared with carbon (at approximately 100 keV ?m and 100 MeV cm2g). Both sets of measurements also show a greater proportion of high LET events for oxygen compared with carbon, and the higher LET of the heavy recoil edge in the oxygen measurement is also evident in both cases. The main difference between the two sets of measurements, as Binns et al point out, lies in the relative magnitude of the alpha component: for both oxygen and carbon their alpha to proton ratio is greater than ours. However, it is the similarity in shape of the two datasets which provides validation of the experimental routes used to determine elemental kerma in neutron therapy beams. Letter-to-the-editor

  3. Assessing the use of the Air Quality Health Index by vulnerable populations in a 'low-risk' region: A pilot study.

    Science.gov (United States)

    Spurr, K; Pendergast, N; MacDonald, S

    2014-01-01

    Several studies have shown a relationship between exposure to outdoor air pollution and adverse health effects, and that people with specific chronic diseases appear to be particularly vulnerable. An important opportunity exists for respiratory therapists to inform at-risk clients, especially those with lung disease, about outdoor air pollution and its role in self-management. The Air Quality Health Index (AQHI), a national program led by Health Canada and Environment Canada, is intended to inform individuals about the level of health risk associated with air pollution in Canadian communities, and to provide a tool to manage those risks. The main purpose of the present study was to assess the use of the AQHI by vulnerable populations in a 'low-risk' (AQHI ?3) region. The specific objectives were: to develop and evaluate an AQHI education strategy; to investigate whether awareness of the AQHI impacts self-management in vulnerable populations in low-risk regions; and to identify enabling factors and/or barriers concerning use of the AQHI by both health care professionals and their patients. A pilot study was conducted using a small convenience sample of clients/patients and educators at respiratory clinics across Nova Scotia. A short educational activity on the utility and application of the AQHI was incorporated into their regular disease management plans and surveys were administered pre- and posteducational intervention. Twenty-one clients from three respiratory clinics consented to participate in the study and received the AQHI education program. Using a Wilcoxon signed-rank test with paired data, five of six survey questions had statistically significant changes in response to pre- and posteducation. Some common themes that emerged from qualitative data collected included: limited access to the Internet; lack of its reporting in the media; confusion with other indexes; and relevancy of the AQHI in Nova Scotia, a 'low-risk' region. An AQHI educational program improved knowledge and use of the AQHI reported by respiratory clinic patients. Respiratory educators reported the AQHI education program was relatively simple to implement into their chronic disease education plan. A larger-scale study involving participants residing in a moderate- or high-risk region is recommended. PMID:26078611

  4. Geomagnetic activity related NOx enhancements and polar surface air temperature variability in a chemistry climate model: modulation of the NAM index

    Directory of Open Access Journals (Sweden)

    P. Jöckel

    2010-12-01

    Full Text Available The atmospheric chemistry general circulation model ECHAM5/MESSy is used to simulate polar surface air temperature effects of geomagnetic activity variations. A transient model simulation was performed for the years 1960–2004 and is shown to develop polar surface air temperature patterns that depend on geomagnetic activity strength, similar to previous studies. In order to eliminate influencing factors such as sea surface temperatures (SST or UV variations, two nine-year long simulations were carried out, with strong and weak geomagnetic activity, respectively, while all other boundary conditions were held to year 2000 levels. Statistically significant temperature effects that were observed in previous reanalysis and model results are also obtained from this set of simulations, suggesting that such patterns are indeed related to geomagnetic activity. In the model, strong geomagnetic activity and the associated NOx enhancements lead to polar stratospheric ozone loss. Compared with the simulation with weak geomagnetic activity, the ozone loss causes a decrease in ozone radiative cooling and thus a temperature increase in the polar winter mesosphere. Similar to previous studies, a cooling is found below the stratopause, which other authors have attributed to a decrease in the mean meridional circulation. In the polar stratosphere this leads to a more stable vortex. A strong (weak Northern Hemisphere vortex is known to be associated with a positive (negative Northern Annular Mode (NAM index; our simulations exhibit a positive NAM index for strong geomagnetic activity, and a negative NAM for weak geomagnetic activity. Such NAM anomalies have been shown to propagate to the surface, and this is also seen in the model simulations. NAM anomalies are known to lead to specific surface temperature anomalies: a positive NAM is associated with warmer than average northern Eurasia and colder than average eastern North Atlantic. This is also the case in our simulation. Our simulations suggest a link between geomagnetic activity, ozone loss, stratospheric cooling, the NAM, and surface temperature variability.

  5. High NDVI and Potential Canopy Photosynthesis of South American Subtropical Forests despite Seasonal Changes in Leaf Area Index and Air Temperature

    Directory of Open Access Journals (Sweden)

    Piedad M. Cristiano

    2014-02-01

    Full Text Available The canopy photosynthesis and carbon balance of the subtropical forests are not well studied compared to temperate and tropical forest ecosystems. The main objective of this study was to assess the seasonal dynamics of Normalized Difference Vegetation Index (NDVI and potential canopy photosynthesis in relation to seasonal changes in leaf area index (LAI, chlorophyll concentration, and air temperatures of NE Argentina subtropical forests throughout the year. We included in the analysis several tree plantations (Pinus, Eucalyptus and Araucaria species that are known to have high productivity. Field studies in native forests and tree plantations were conducted; stem growth rates, LAI and leaf chlorophyll concentration were measured. MODIS satellite-derived LAI (1 km SIN Grid and NDVI (250m SIN Grid from February 2000 to 2012 were used as a proxy of seasonal dynamics of potential photosynthetic activity at the stand level. The remote sensing LAI of the subtropical forests decreased every year from 6 to 5 during the cold season, similar to field LAI measurements, when temperatures were 10 °C lower than during the summer. The yearly maximum NDVI values were observed during a few months in autumn and spring (March through May and November, respectively because high and low air temperatures may have a small detrimental effect on photosynthetic activity during both the warm and the cold seasons. Leaf chlorophyll concentration was higher during the cold season than the warm season which may have a compensatory effect on the seasonal variation of the NDVI values. The NDVI of the subtropical forest stands remained high and fairly constant throughout the year (the intra-annual coefficient of variation was 1.9%, and were comparable to the values of high-yield tree plantations. These results suggest that the humid subtropical forests in NE Argentina potentially could maintain high canopy photosynthetic activity throughout the year and thus this ecosystem may be a large carbon sink.

  6. Spatial Correlations of Anomaly Time Series of AIRS Version-6 Land Surface Skin Temperatures with the Nino-4 Index

    Science.gov (United States)

    Susskind, Joel; Lee, Jae N.; Iredell, Lena

    2013-01-01

    The AIRS Science Team Version-6 data set is a valuable resource for meteorological studies. Quality Controlled earth's surface skin temperatures are produced on a 45 km x 45 km spatial scale under most cloud cover conditions. The same retrieval algorithm is used for all surface types under all conditions. This study used eleven years of AIRS monthly mean surface skin temperature and cloud cover products to show that land surface skin temperatures have decreased significantly in some areas and increased significantly in other areas over the period September 2002 through August 2013. These changes occurred primarily at 1:30 PM but not at 1:30 AM. Cooling land areas contained corresponding increases in cloud cover over this time period, with the reverse being true for warming land areas. The cloud cover anomaly patterns for a given month are affected significantly by El Nino/La Nina activity, and anomalies in cloud cover are a driving force behind anomalies in land surface skin temperature.

  7. Relationship between maternal pre-pregnancy body mass index, gestational weight gain and childhood fatness at 6-7 years by air displacement plethysmography.

    Science.gov (United States)

    Castillo, Helen; Santos, Iná S; Matijasevich, Alicia

    2015-10-01

    This study aims to investigate the effect of maternal pre-pregnancy body mass index (BMI) and gestational weight gain (GWG) on offspring body composition. In this prospective cohort study, offspring body composition at 6 years of age was obtained through air displacement plethysmography. Linear regression was used to obtain crude and adjusted coefficients. Information regarding offspring body composition and maternal pre-pregnancy BMI was available for 3156 children and on offspring body composition and GWG for 3129 children. There was a direct association of maternal pre-pregnancy BMI and GWG with offspring's fat mass (FM), fat-free mass (FFM), fat mass index (FMI), fat-free mass index (FFMI) and body fat percent (BF%) in crude and adjusted analyses. After adjustment for co-variables, for each kg?m(-2) of maternal pre-pregnancy BMI increase, there was a mean increment of 0.13?kg in the offspring FFM, 0.06?kg?m(-2) in FFMI, 0.11?kg in FM, 0.07?kg?m(-2) in FMI and 0.18% in BF%. For each kilogram of maternal GWG increase, there was a mean increment of 0.08?kg in offspring's FM, 0.05?kg?m(-2) in FMI, 0.04?kg in FFM, 0.01?kg?m(-2) in FFMI and 0.18 % in BF%. Mothers with a higher pre-pregnancy BMI or GWG tend to have children with greater adiposity at age 6 years. Fetal overnutrition is more likely among mothers with greater BMI during pregnancy; as a consequence, it can accelerate the childhood obesity epidemic. PMID:25850519

  8. Patient-specific kerma-area product as an exposure estimator in computed tomography: The concept and typical values

    International Nuclear Information System (INIS)

    The concept of the patient-specific kerma-area product (PSKAP) as an exposure estimator in computed tomography (CT) was suggested, but no detailed information on how to evaluate this quantity in practice was given. We extend the idea by proposing (i) a rigorous definition of PSKAP, and (ii) a method for its evaluation by a CT scanner. To demonstrate the performance of the method, we used the Siemens Somatom Open CT scanner to obtain PSKAP values (here denoted as PPSKA) for the standard CT dosimetry head phantom

  9. Calibration methodology application of kerma area product meters in situ: Preliminary results

    International Nuclear Information System (INIS)

    The kerma-area product (KAP) is a useful quantity to establish the reference levels of conventional X-ray examinations. It can be obtained by measurements carried out with a KAP meter on a plane parallel transmission ionization chamber mounted on the X-ray system. A KAP meter can be calibrated in laboratory or in situ, where it is used. It is important to use one reference KAP meter in order to obtain reliable quantity of doses on the patient. The Patient Dose Calibrator (PDC) is a new equipment from Radcal that measures KAP. It was manufactured following the IEC 60580 recommendations, an international standard for KAP meters. This study had the aim to calibrate KAP meters using the PDC in situ. Previous studies and the quality control program of the PDC have shown that it has good function in characterization tests of dosimeters with ionization chamber and it also has low energy dependence. Three types of KAP meters were calibrated in four different diagnostic X-ray equipments. The voltages used in the two first calibrations were 50 kV, 70 kV, 100 kV and 120 kV. The other two used 50 kV, 70 kV and 90 kV. This was related to the equipments limitations. The field sizes used for the calibration were 10 cm, 20 cm and 30 cm. The calibrations were done in three different cities with the purpose to analyze the reproducibility of the PDC. The results gave the calibration coefficient for each KAP meter and showed that the PDC can be used as a reference instrument to calibrate clinical KAP meters. - Highlights: • The Patient Dose Calibrator (PDC) is a new equipment from Radcal that measures KAP. • This study aimed the calibration of KAP meters in situ using the PDC as a reference. • The method used for the calibration of the KAP meters was the tandem method. • This instrument calculates the dose that the patient receives during an X-ray examination. • The calibration procedure is important to correct the measurements performed with KAP meters

  10. Air pollution reduction with respect to the conversion of biomass into electricity and heat. Emission and cost indexes

    International Nuclear Information System (INIS)

    Although biomass conversion is considered to be a CO2-free method of producing electricity and heat other emissions have to be taken into account: SO2, NOx, HCl, HF, Hg, Cd, dusts, etc. The aim of the study on the title subject is to support the Dutch Ministry of Housing, Planning and Environment (VROM) in the determination of feasible emission standards for bioconversion installations. The Centre for Energy conservation and clean technology (CE) compiled information on the costs for flue gas purification for different degrees of purification. Because of the fact that the composition of flue gases strongly depends on the biomass flow and the applied conversion technique, both biomass flows and conversion techniques must be distinguished. The following biomass conversion techniques were studied: large-scale combustion of wood wastes and sludges, large-scale gasification of wood wastes, cocombustion of wood wastes and sludges, small-scale combustion of wood wastes and chicken manure, small-scale gasification of wood wastes, and fermentation of wastes from vegetables, fruits and gardens. For each combination it is determined what the emissions are in case of a minimal flue gas purification, what the emissions are and how much additional costs are involved in case the regulations in the BLA (decree on air pollution of waste incineration) are taken into account, and what the emissions are and how much additional costs are involved for a number of levels in between the two fore-mentioned cases. refs

  11. Scattering study at free air ionization chamber diaphragm; Estudo do espalhamento no diafragma da camara de ionizacao de ar livre

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Alexandre Lo Bianco dos

    2011-07-01

    The maim of this work consisted in the assessment of the correction factor for air kerma, due to scattered radiation in the diaphragm of the free-air ionization chamber model 481. LNMRl measurements were made to acquire x-ray spectra corresponding to the Qualities RQR-M, described in IEC 61627 standards (2005). These spectra were used as input data in the MC simulations. The operational range of energy spectra provide up to 35 keV. This energy range is typically used in diagnostic radiology, although there is not primary standard for air kerma. The determination of this factor is a fundamental process in the primary standardization of the air kerma. These factors were obtained by computer simulation using the Penelope code. The results are k{sub RQR-M1}=0,9946, k{sub RQR} {sub -M2}=0,9932, k{sub RQR-M3}=0,9978 and k{sub RQR-M4}=0,9885; with uncertainties of 0,007 and coverage factor equal to 2. lt can be concluded that, with respect to the diaphragm, the chamber can be used in the primary standard of air kerma. (author)

  12. 2014 Environmental Performance Index (EPI)

    Data.gov (United States)

    National Aeronautics and Space Administration — The 2014 Environmental Performance Index (EPI) ranks 178 countries on 20 performance indicators in the following 9 policy categories: health impacts, air quality,...

  13. Importance of the neutrons kerma coefficient in the planning of Brachytherapy treatments with Cf-252 sources; Importancia del coeficiente de kerma de neutrones en la planeacion de tratamientos de Braquiterapia con fuentes de Cf-252

    Energy Technology Data Exchange (ETDEWEB)

    Paredes G, L.; Balcazar G, M. [ININ, 52045 Ocoyocac, Estado de Mexico (Mexico); Azorin N, J. [Universidad Autonoma Metropolitana, 09000 Mexico D.F. (Mexico); Francois L, J.L. [UNAM, 04500 Mexico D.F. (Mexico)]. e-mail: lpg@nuclear.inin.mx

    2006-07-01

    The Cf-252 is a fast neutrons emitting radioisotope by spontaneous fission that can be used as sealed source in medicine applications, industry and research. Commercially its offer sources of different sizes, compact and with a fast neutrons emission of the order of 10{sup 6} n/s-{mu}g and an energy spectra that presents respectively maxim and average energy in 2.1 MeV and 0.7 MeV. In medicine new applications are being developed for the treatment of patient with hypoxic and voluminous tumors, where the therapy with photons has not given positive results, as well as for the protocols of therapy treatment by boron neutron capture, where very small sources of Cf-252 will be used with the interstitial brachytherapy technique of high and low dose rate. In this work an analysis of how the small differences that exist in the elementary composition of 4 wicked tumors, 4 ICRU healthy tissues and 3 substitute materials of ICRU tissue used in dosimetry are presented, its generate changes in the neutrons kerma coefficient in function of the energy and consequently in the absorbed dose in the interval of 11 eV to 29 MeV. These differences can produce maximum variations of the neutron kerma coefficients ratio for E{sub n} > 1 keV of the one: 15% tumor/ICRU guest healthy tissue, 12% ICRU tumor/muscle, 12% ICRU healthy tissues ICRU/ICRU muscle, 22% substitutes tissue/tumor and 22% ICRU substitutes tissue/muscle. Also, it was found that the average value of the neutrons kerma coefficient for the 4 wicked tumors is from 6% to 7% smaller that the average value for the soft tissue in the interval energy of interest for therapy with fast neutrons with E{sub n} > 1 MeV. These results have a special importance during the planning process of brachytherapy treatments with sources of {sup 252}Cf, to optimize and to individualize the patients treatments. (Author)

  14. Fully-automated estimation of actual to potential evapotranspiration in the Everglades using Landsat and air temperature data as inputs to the Vegetation Index-Temperature Trapezoid method

    Science.gov (United States)

    Yagci, A. L.; Jones, J. W.

    2014-12-01

    While the greater Everglades contains a vast wetland, evapotranspiration (ET) is a major source of water "loss" from the system. Like other ecosystems, the Everglades is vulnerable to drought. Everglades restoration science and resource management requires information on the spatial and temporal distribution of ET. We developed a fully-automated ET model using the Vegetation Index-Temperature Trapezoid concept. The model was tested and evaluated against in-situ ET observations collected at the Shark River Slough Mangrove Forest eddy-covariance tower in Everglades National Park (Sitename / FLUXNET ID: Florida Everglades Shark River Slough Mangrove Forest / US-Skr). It uses Landsat Surface Reflectance Climate Data from Landsat 5, and Landsat 5 thermal and air temperature data from the Daily Gridded Surface Dataset to output the ratio of actual evapotranspiration (AET) and potential evapotranspiration (PET). When multiplied with a PET estimate, this output can be used to estimate ET at high spatial resolution. Furthermore, it can be used to downscale coarse resolution ET and PET products. Two example outputs covering the agricultural lands north of the major Everglades wetlands extracted from two different dates are shown below along with a National Land Cover Database image from 2011. The irrigated and non-irrigated farms are easily distinguishable from the background (i.e., natural land covers). Open water retained the highest AET/PET ratio. Wetlands had a higher AET/PET ratio than farmlands. The main challenge in this study area is prolonged cloudiness during the growing season.

  15. Evaluation of skin entry kerma in radiological examinations at the Hospital de Clinicas, Parana, Brazil; Avaliacao de kerma de entrada na pele em exames radiologicos no Hospital de Clinicas do Parana, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Porto, Lorena E.; Schelin, Hugo R.; Santos, Amanda C. dos; Bunick, Ana Paula; Paschuk, Sergei; Denyak, Valeriy [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil); Tilly Junior, Joao G. [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Hospital de Clinicas; Khoury, Helen J., E-mail: khoury@ufpe.b [Universidade Federal de Pernambuco (UFPE/DEN), Recife, PE (Brazil). Dept. de Energia Nuclear

    2011-10-26

    This paper evaluates the skin entry dose of pediatric and adults patients when submitted to radiological examinations at the Hospital de Clinicas do Parana, Brazil, as part integrate of the data assessment of International Atomic Energy Agency (IAEA) for Latin America. It was performed measurements of dose for evaluation of skin entry kerma in pediatric patients in thorax AP/PA examinations, adults of thorax in AP/PA, cranio caudal mammography and median lateral and patients of computerized tomography in examination of head, thorax and abdomen. The obtained data demonstrate the necessity of verification of diagnostic analysis standards. The great value amplitudes demonstrate the incompatibility of examination executions with those recommended by the literature. The dose values presented partially inside the range recommended and the other over the expected for the due examination when compared with the literature

  16. Cavity's theory of Bragg-Gray applied to ionization free-air chamber

    International Nuclear Information System (INIS)

    Ionization's chambers are kinds of dosimeters more useful to measurements such as required in radiotherapy. Are detectors of non pulse type (mean effect) and gaseous, calibrate in Kerma, unit Gray (Gy).The objective of this work is to relate the physical theory existing and the construction shape of the primary standard, that is the ionization of free-air chamber with variable volume, manufactured by Victoreen Instruments, used to measure magnitude air Kerma performed by the 'Laboratorio Nacional de Metrologia das Radiacoes Ionizantes' from Instituto de Radioprotecao e Dosimetria - LNMRI-IRD. For in such a way, will be done an evaluation of the chamber capability, and the sensibility of radiations of low energy, range from 20 kV to 80 kV, in the qualities of mammography not attenuate, mammography attenuate, diagnostic, therapy e protection through the construction's acquaintance, dimensions of pieces components and operational tests. Concerning the chamber's construction, the mechanical set consists of two cylinders of aluminium concentrically that moves axially between itself, objectifying the variation of internal volume (variable volume). The practical application of the Bragg-Gray cavity's theory can be applied to the chamber, where the reasons of the absorbed dose in different means to the same fluency is equal to the reason of stopping powers of two means. >From the definition of Kerma we can obtain the adsorbed dose and existing particles in (CPE), the absorbed dose is equal to the Kerma's collision. (author)

  17. Index Bioclimatic "Wind-Chill"

    Directory of Open Access Journals (Sweden)

    Teodoreanu Elena

    2015-05-01

    Full Text Available This paper presents an important bioclimatic index which shows the influence of wind on the human body thermoregulation. When the air temperature is high, the wind increases thermal comfort. But more important for the body is the wind when the air temperature is low. When the air temperature is lower and wind speed higher, the human body is threatening to freeze faster. Cold wind index is used in Canada, USA, Russia (temperature "equivalent" to the facial skin etc., in the weather forecast every day in the cold season. The index can be used and for bioclimatic regionalization, in the form of skin temperature index.

  18. Determination of mass attenuation coefficients, effective atomic numbers, effective electron numbers and kermas for Earth and Martian soils

    Energy Technology Data Exchange (ETDEWEB)

    Un, A., E-mail: ademun25@yahoo.com [Agr Latin-Small-Letter-Dotless-I Ibrahim Cecen University, Faculty of Arts and Sciences, Department of Physics, 04100 Agr Latin-Small-Letter-Dotless-I (Turkey); Sahin, Y. [Atatuerk University, Faculty of Sciences, Department of Physics, 25240 Erzurum (Turkey)

    2012-10-01

    Highlights: Black-Right-Pointing-Pointer The present work have been expected to be lead to extraterrestrial research. Black-Right-Pointing-Pointer Our work have thrown light on the radiation physics and the applications. Black-Right-Pointing-Pointer The data which are used to shielding application are not available in the literature. - Abstract: Total mass attenuation coefficients, effective atomic numbers, effective electron numbers and kerma values for Earth and Martian soils are calculated in the energy range from 1 keV to 100 GeV. The values of mass attenuation and absorption coefficients used in calculations are taken from the WinXCOM program and correct data base. Contributions of different scatterings on the total mass attenuation coefficients of the soils are presented. In addition, the obtained results for Martian soils are compared with the results for Earth soils. The similarities of Earth and Martian soils are also investigated.

  19. Use of an index to reflect the aggregate burden of long-term exposure to criteria air pollutants in the United States.

    OpenAIRE

    Kyle, Amy D.; Woodruff, Tracey J.; Buffler, Patricia A; Davis, Devra L

    2002-01-01

    Air pollution control in the United States for five common pollutants--particulate matter, ground-level ozone, sulfur dioxide, nitrogen dioxide, and carbon monoxide--is based partly on the attainment of ambient air quality standards that represent a level of air pollution regarded as safe. Regulatory and health agencies often focus on whether standards for short periods are attained; the number of days that standards are exceeded is used to track progress. Efforts to explain air pollution to ...

  20. Evaluated cross section libraries and kerma factors for neutrons up to 100 MeV on 16O and 14N

    International Nuclear Information System (INIS)

    We present evaluations of the interaction of 20 to 100 MeV neutrons with oxygen and nitrogen nuclei, which follows on from our previous work on carbon. Our aim is to accurately represent integrated cross sections, inclusive emission spectra, and kerma factors, in a data library which can be used in radiation transport calculations. We apply the FKK-GNASH nuclear model code, which includes Hauser-Feshbach, preequilibrium, and direct reaction mechanisms, and use experimental measurements to optimize the calculations. We determine total, elastic, and nonelastic cross sections, angle-energy correlated emission spectra, for light ejectiles with A?4 and gamma-rays, and average energy depositions. Our results for charged-particle emission spectra agree well with the measurements of Subramanian et al.. We compare kerma factors derived from our evaluated cross sections with experimental data, providing an integral benchmarking of our work. The evaluated data libraries are available as electronic files

  1. Calculation and evaluation of cross-sections and kerma factors for neutrons up to 100 MeV on {sup 16}O and {sup 14}N

    Energy Technology Data Exchange (ETDEWEB)

    Chadwick, M.B. [California Univ., Livermor, CA (United States). Lawrence Livermore National Lab.; Young, P.G.

    1997-03-01

    We present evaluations of the interaction of neutrons with energies between 20 and 100 MeV with oxygen and nitrogen nuclei, which follows on from our previous work on carbon. Our aim is to accurately represent integrated cross sections, inclusive emission spectra, and kerma factors, in a data library which can be used in radiation transport calculations. We apply the FKK-GNASH nuclear model code, which includes Hauser-Feshbach, preequilibrium, and direct reaction mechanisms, and use experimental measurements to optimize the calculations. We determine total, elastic, and nonelastic cross sections, angle-energy correlated emission spectra for light ejectiles with A {<=} 4 and gamma-rays, and average energy depositions. Our results for charged-particle emission spectra agree well with the measurements of Subramanian et al. We compare kerma factors derived from our evaluated cross sections with experimental data, providing an integral benchmarking of our work. (author). 52 refs.

  2. The tree BVOC index

    International Nuclear Information System (INIS)

    Urban trees can produce a number of benefits, among them improved air quality. Biogenic volatile organic compounds (BVOCs) emitted by some species are ozone precursors. Modifying future tree planting to favor lower-emitting species can reduce these emissions and aid air management districts in meeting federally mandated emissions reductions for these compounds. Changes in BVOC emissions are calculated as the result of transitioning to a lower-emitting species mix in future planting. A simplified method for calculating the emissions reduction and a Tree BVOC index based on the calculated reduction is described. An example illustrates the use of the index as a tool for implementation and monitoring of a tree program designed to reduce BVOC emissions as a control measure being developed as part of the State Implementation Plan (SIP) for the Sacramento Federal Nonattainment Area. - Highlights: ? A Tree BVOC index based on reduced emissions from low emitting trees is described. ? An example illustrates use of the index as an implementation and monitoring tool. ? This index could be useful for including urban trees in air quality mitigation plans. - A tree BVOC index is presented that calculates reduced BVOC emissions from planting lower-emitting urban tree species that has potential application for SIP compliance.

  3. Doses monitoring in radiology: calibration of air kerma-area product (P{sub KA}) meters; Monitoracao de doses em radiologia: a calibracao de medidores do produto kerma-area (P{sub KA})

    Energy Technology Data Exchange (ETDEWEB)

    Terini, Ricardo Andrade; Campelo, Maria Carolina de Santana; Almeida Junior, Jose Neres de, E-mail: rterini@pucsp.br [Pontificia Universidade Catolica de Sao Paulo (PUC-SP), SP (Brazil); Herdade, Silvio Bruni; Pereira, Marco Aurelio Guedes [Universidade de Sao Paulo (IEE/USP), SP (Brazil). Instituto de Energia e Ambiente

    2013-11-15

    Materials and methods: different qualities of both incident and transmitted beams were utilized in conditions similar to a clinical setting, analyzing the influence from the reference dosimeter, from the distance between meters, from the filtration and from the average beam energy. Calibrations were performed directly against a standard 30 cm{sup 3} cylindrical chamber or a parallel-plate monitor chamber, and indirectly against the PDC meter. Results: the lowest energy dependence was observed for transmitted beams. The cross calibration between the Diamentor E2 and the PDC meters, and the PDC presented the greatest propagation of uncertainties. Conclusion: the calibration coefficient of the PDC meter showed to be more stable with voltage, while the Diamentor E2 calibration coefficient was more variable. On the other hand, the PDC meter presented greater uncertainty in readings (5.0%) than with the use of the monitor chamber (3.5%) as a reference. (author)

  4. Indexing books

    CERN Document Server

    Mulvany, Nancy C

    2009-01-01

    Since 1994, Nancy Mulvany's Indexing Books has been the gold standard for thousands of professional indexers, editors, and authors. This long-awaited second edition, expanded and completely updated, will be equally revered.Like its predecessor, this edition of Indexing Books offers comprehensive, reliable treatment of indexing principles and practices relevant to authors and indexers alike. In addition to practical advice, the book presents a big-picture perspective on the nature and purpose of indexes and their role in published works. New to this edition are discus

  5. Evaluated cross-section libraries and kerma factors for neutrons up to 100 MeV on 12C

    International Nuclear Information System (INIS)

    A program is being carried out at Lawrence Livermore National Laboratory to develop high-energy evaluated nuclear data libraries for use in Monte Carlo simulations of cancer radiation therapy. In this report we describe evaluated cross sections and kerma factors for neutrons with incident energies up to 100 MeV on 12C. The aim of this effort is to incorporate advanced nuclear physics modeling methods, with new experimental measurements, to generate cross section libraries needed for an accurate simulation of dose deposition in fast neutron therapy. The evaluated libraries are based mainly on nuclear model calculations, benchmarked to experimental measurements where they exist. We use the GNASH code system, which includes Hauser-Feshbach, preequilibrium, and direct reaction mechanisms. The libraries tabulate elastic and nonelastic cross sections, angle-energy correlated production spectra for light ejectiles with A?and kinetic energies given to light ejectiles and heavy recoil fragments. The major steps involved in this effort are: (1) development and validation of nuclear models for incident energies up to 100 MeV; (2) collation of experimental measurements, including new results from Louvain-la-Nueve and Los Alamos; (3) extension of the Livermore ENDL formats for representing high-energy data; (4) calculation and evaluation of nuclear data; and (5) validation of the libraries. We describe the evaluations in detail, with particular emphasis on our new high-energy modeling developments. Our evaluations agree well with experimental measurements of integrated and differential cross sections. We compare our results with the recent ENDF/B-VI evaluation which extends up to 32 MeV

  6. Detection and estimation trends linked to air quality and mortality on French Riviera over the 1990-2005 period to develop a prediction model of an aggregate risk index

    Science.gov (United States)

    Sicard, P.; Mangin, A.; Hebel, P.; Lesne, O.; Malléa, P.

    2009-04-01

    There is a profound relation between human health and well being from the one side and air pollution levels from the other. Air quality in South of France and more specifically in Nice, is known to be bad, especially in summer. The main objectives are to establish correlations between air pollution, exposure of people and reactivity of these people to this aggression, to validate a risk index built from air quality and pollen data in the area of Nice and to construct a prediction model of this sanitary index. The spatial extent of the experiment will be mainly the territory of "Alpes Maritimes". All the tasks are performed in collaboration with the "Heath-Environment Network" of the "Centre Hospitalier Universitaire" of Nice. The development of an adequate tool for observation (health index and/or indices per pathology) to understand impacts of pollution levels in an area is of utmost importance. These indexes should take into account the possible adverse effects associated with the coexistence of all the pollutants and environmental parameters. This tool must be able to inform the citizens about the levels of pollution in an adequate and understandable way but also to be used by relevant authorities to take a series of predetermined measures to protect the health of the population. This paper describes the first step to construct a prediction model of this sanitary index with a confidence interval 99% (and 95%): detection and estimation trends observed in concentrations of pollutants, emissions and mortality over the 1990-2005 period in the "Alpes Maritimes" area. The non-parametric Mann-Kendall test has been developed for detecting and estimating monotonic trends in the time series and applied in our study at annual values of pollutants air concentrations. An important objective of many environmental monitoring programs is to detect changes or trends in pollution levels over time. Over the period 1990-2005, concerning the emissions of the main pollutants, we obtained significant decreasing trends. Between 1994 and 2005, from the SO2 concentrations, decreasing trends of 1.2 %.year-1 (urban stations) and of 5.4 %.year-1 (traffic stations) were calculated. Over the same period, we obtained a decreasing trend of 1.3 %.year-1 for the NO2 concentrations (urban stations) and of 3.1 %.year-1 for the traffic stations. In addition, a decreasing trend of 0.5 %.year-1 was calculated for the suburban stations over the 1998-2005 period. Globally, the concentration of the major pollutants showed a clear downward trend and those main reductions have reflected the reduction policy of the emissions over twenty years. By considering the ozone mean values in urban areas over the 1997-2005 period, an increasing of 3.0 %.year-1 was obtained with annual averages and 3.9 %.year-1 with median values. Over the 1990-2005 period, we obtained significant decreasing trends concerning the "ischemic heart diseases" (- 1.20 %.year-1) and "asthma" (- 4.03 %.year-1) categories. No significant sex-related difference was identified for these groups. An annual change rate of + 0.31 %.year-1 for the "airway diseases" and of + 2.50%.year-1 for the "unknown causes" were identified. For these categories, we noted a sex-related difference. In fact, we obtained for males a decreasing trend contrary to females.

  7. Evaluation of cross sections and calculation of kerma factors for neutrons up to 80 MeV on {sup 12}C

    Energy Technology Data Exchange (ETDEWEB)

    Harada, M.; Watanabe, Y. [Kyushu Univ., Fukuoka (Japan); Chiba, S.; Fukahori, T.

    1997-03-01

    We have evaluated the cross sections for neutrons with incident energies from 20 to 80 MeV on {sup 12}C for the JENDL high-energy file. The total cross sections were determined by a generalized least-squares method with available experimental data. The cross sections of elastic and inelastic scattering to the first 2{sup +} were evaluated with the theoretical calculations. The optical potentials necessary for these calculations were derived using a microscopic approach by Jeukenne-Lejeune-Mahaux. For the evaluation of double differential emission cross sections (DDXs), we have developed a code system SCINFUL/DDX in which total 35 reactions including the 3-body simultaneous breakup process (n+{sup 12}C {yields} n+{alpha}+{sup 8}Be) can be taken into consideration in terms of a Monte Carlo method, and have calculated the DDXs of all light-emissions (A{<=}4) and heavier reaction products. The results for protons, deuterons, and alphas showed overall good agreement with experimental data. The code is also applicable for calculations of total and partial kerma factors. Total kerma factors calculated for energies from 20 to 80 MeV were compared with the measurements and the other latest evaluations from the viewpoints of medical application and nuclear heating estimation. (author)

  8. Characterization of a free-air ionization chamber in direct X-ray beams as used in mammography; Caracterizacao de uma camara de ionizacao de ar-livre em feixes diretos de raios X utilizados em mamografia

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Mateus Hilario de

    2014-08-01

    At this work stability and characterization tests were undertaken on a Victoreen free-air ionization chamber, model 481. The tests were realized using direct X-ray beams as a contribution for its establishment as a primary standard system of the quantity air kerma. The characterization tests were: saturation curve, ion collection efficiency, polarity effect, response linearity with the air kerma rate and response linearity with the chamber volume variation. The ion collection efficiency allowed the determination of the ion recombination factor. Most of the test results showed agreement with the limits established by international standards. Furthermore, the air attenuation factors for the mammography beams with aluminum and molybdenum filters were obtained. The factors for photon transmission and scattering at the diaphragm edges were also determined for mammography beams with aluminum filter and for the standard beam with molybdenum filter. (author)

  9. AP Index

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Planetary Amplitude index - Bartels 1951. The a-index ranges from 0 to 400 and represents a K-value converted to a linear scale in gammas (nanoTeslas)--a scale that...

  10. Intelligent indexing

    International Nuclear Information System (INIS)

    In this paper we discuss the relevance of artificial intelligence to the automatic indexing of natural language text. We describe the use of domain-specific semantically-based thesauruses and address the problem of creating adequate knowledge bases for intelligent indexing systems. We also discuss the relevance of the Hilbert space ?2 to the compact representation of documents and to the definition of the similarity of natural language texts. (author). 17 refs., 2 figs

  11. Preliminary results on characterization tests of a free-air chamber

    International Nuclear Information System (INIS)

    Free-air chambers are widely used in radiation metrology laboratories as primary standards for air kerma in the range of low and medium x-ray energies. There are two types of free-air ionization chambers: the parallel-plate type and the cylindrical type. The first one is used as primary standard at laboratories as the NIST, BIPM and NPL. The cylindrical type, on the other hand, is used in the standard calibration laboratories of Germany, Italy and Taiwan. In 1961, Attix proposed a design of a cylindrical free-air ionization chamber with a variable length presenting some advantages over the fixed-length design. The Instituto de Pesquisas Energeticas e Nucleares (IPEN) has a Victoreen chamber, model 481, based on this design for x-ray energies up 50 keV. The objective of this study is to investigate the possibility of using this chamber as a primary standard of air kerma in the Calibration Laboratory of IPEN. In this work are presented the preliminary results of the characterization tests of the free-air ionization chamber: leakage current, stability of response, saturation curve, collection efficiency, response linearity and response linearity with the cylinder displacement. (author)

  12. Louisiana ESI: INDEX (Index Polygons)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing the boundaries of all the hardcopy cartographic products produced as part of the Environmental Sensitivity Index...

  13. Virginia ESI: INDEX (Index Polygons)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing the boundaries of all hardcopy cartographic products produced as part of the Environmental Sensitivity Index...

  14. Estimation of entrance dose on chest radiographs according to the exposure index on Computerized Radiology System: preliminary results

    International Nuclear Information System (INIS)

    Digital radiology has improved image quality in radiographs in comparison to screen/film systems though the visual control of the quantity of radiation involved on these exams became more demanding due to the low perception of over and underexposed images. Therefore, this study aims to analyze the exposure index (EI) from chest examinations and relate them to the entrance skin dose. Indices from 29 patients and kerma entrance dose were correlated. A correlation coefficient equal to 0,6881 was calculated. EI and entrance dose are correlated positive and moderately, indicating the relevance to deepen the subject. (author)

  15. A comparison of in-air and in-water calibration of a dosimetry system used for radiation dose assessment in cancer therapy

    OpenAIRE

    Arshed Waheed; Mahmood Khalid; Qazi Ikramullah; Ullah Asad; Akhter Perveen; Ahmad Salman Syed; Jamil Zeeshan

    2010-01-01

    An accurate calibration of the therapy level radiation dosimetry system has a pivotal role in the accuracy of dose delivery to cancer patients. The two methods used for obtaining a tissue equivalent calibration of the system: air kerma calibration and its conversion to a tissue equivalent value (absorbed dose to water) and direct calibration of the system in a water phantom, have been compared for identical irradiation geometry. It was found that the deviation between the two methods remained...

  16. Indexing mechanisms

    International Nuclear Information System (INIS)

    It is stated that the indexing mechanism described can be used in a nuclear reactor fuel element inspection rig. It comprises a tubular body adapted to house a canister containing a number of fuel elements located longtitudinally, and has two chucks spaced apart for displacing the fuel elements longitudinally in a stepwise manner, together with a plunger mechanism for displacing them successively into the chucks. A measuring unit is located between the chucks for measuring the diameter of the fuel elements at intervals about their circumferences, and a secondary indexing mechanism is provided for rotating the measuring unit in a stepwise manner. (U.K.)

  17. Rib index

    OpenAIRE

    Grivas, Theodoros B

    2014-01-01

    This article analyzes the double rib contour sign (DRCS) and the rib index (RI). The analyzed topics are 1. the history of presentations – publication of DRCS-RI, 2. the study source origin: school screening for idiopathic scoliosis (IS), 3. what the DRCS and the RI are– Description, 4. the quantification of the DRCS – RI, 5. a reliability study for RI 6. how much the rib index is affected by the distance between the radiation source and the irradiated individual, 7. the implications on IS ae...

  18. Conception and realization of a parallel-plate free-air ionization chamber for the absolute dosimetry of an ultrasoft X-ray beam

    Energy Technology Data Exchange (ETDEWEB)

    Groetz, J.-E., E-mail: jegroetz@univ-fcomte.fr; Mavon, C.; Fromm, M. [Laboratoire Chrono-Environnement, UMR CNRS 6249, Université de Franche-Comté, 16 route de Gray, 25030 Besançon Cedex (France); Ounoughi, N. [Laboratoire Chrono-Environnement, UMR CNRS 6249, Université de Franche-Comté, 16 route de Gray, 25030 Besançon Cedex (France); Laboratoire de Physique des Rayonnements et Applications, Université de Jijel, B.P. 98 Ouled Aissa, Jijel 18000 (Algeria); Belafrites, A. [Laboratoire de Physique des Rayonnements et Applications, Université de Jijel, B.P. 98 Ouled Aissa, Jijel 18000 (Algeria)

    2014-08-15

    We report the design of a millimeter-sized parallel plate free-air ionization chamber (IC) aimed at determining the absolute air kerma rate of an ultra-soft X-ray beam (E = 1.5 keV). The size of the IC was determined so that the measurement volume satisfies the condition of charged-particle equilibrium. The correction factors necessary to properly measure the absolute kerma using the IC have been established. Particular attention was given to the determination of the effective mean energy for the 1.5 keV photons using the PENELOPE code. Other correction factors were determined by means of computer simulation (COMSOL™and FLUKA). Measurements of air kerma rates under specific operating parameters of the lab-bench X-ray source have been performed at various distances from that source and compared to Monte Carlo calculations. We show that the developed ionization chamber makes it possible to determine accurate photon fluence rates in routine work and will constitute substantial time-savings for future radiobiological experiments based on the use of ultra-soft X-rays.

  19. Calculation of conversion coefficients Hp(3)/K air using the PENELOPE Monte Carlo code and comparison with MCNP calculation results

    International Nuclear Information System (INIS)

    The authors report calculations performed using the MNCP and PENELOPE codes to determine the Hp(3)/K air conversion coefficient which allows the Hp(3) dose equivalent to be determined from the measured value of the kerma in the air. They report the definition of the phantom, a 20 cm diameter and 20 cm high cylinder which is considered as representative of a head. Calculations are performed for an energy range corresponding to interventional radiology or cardiology (20 keV-110 keV). Results obtained with both codes are compared

  20. Determination of the air attenuation and electronic loss for the free air concentric cylinders ionization chamber

    International Nuclear Information System (INIS)

    Along the latest years, the LNMRI has been proceeding a continuous research work with a concentric cylinders type free air ionizing chamber (VICTOREEN, model 481), aiming to establish it as a new national standard, and, as a consequence, replace the worldwide accepted secondary standard, calibrated by PTB. Taking into account that the absolute determination of kerma in air with a free air ionizing chamber implies the acquirement of a number of correction factors. The main objective of the present work comprises the determination of the two factors, specifically, electronic loss (ke) and air attenuation (ka). The correction factors were obtained through mammography qualities reference spectrum, using Monte Carlo simulation method. The Penelope code was used in the simulation procedures. Simulations took place in two stages, the acquirement of specters related to the qualities of interest (mammography) with the x ray tube (Pantak, model HF160 e Panalytical, model XRF window), and the free-air ionization chamber. The data were compared to those related to the BIPM chamber, to electronic loss were not detected. The comparison between air attenuation factors was obtained data bellow 0.13%. (author)

  1. Are exposure index values consistent in clinical practice? A multi-manufacturer investigation

    International Nuclear Information System (INIS)

    The advent of digital radiography poses the risk of unnoticed increases in patient dose. Manufacturers have responded to this by offering an exposure index (EI) value to the clinician. Whilst the EI value is a measure of the air kerma at the detector surface, it has been recommended by international agencies as a method of monitoring radiation dose to the patient. Recent studies by the group have shown that EI values are being used in clinical practice to monitor radiation dose and assess image quality. This study aims to compare the clinical consistency of the EI value in computed radiography (CR) and direct digital radiography (DR) systems. An anthropomorphic phantom was used to simulate four common radiographic examinations: skull, pelvis, chest and hand. These examinations were chosen as they provide contrasting exposure parameters, image detail and radiation dose measurements. Four manufacturers were used for comparison: Agfa Gaevert CR, Carestream CR, Philips Digital Diagnost DR and Siemens DR. For each examination, the phantom was placed in the optimal position and exposure parameters were chosen in accordance with European guidelines and clinical practice. Multiple exposures were taken and the EI recorded. All exposure parameters and clinical conditions remained constant throughout. For both DR systems, the EI values remained consistent throughout. No significant change was noted in any examination. In both CR systems, there were noteworthy fluctuations in the EI values for all examinations. The largest for the Agfa system was a variation of 1.88-2.21 for the skull examination. This represents to the clinician a doubling of detector dose, despite all exposure parameters remaining constant. In the Kodak system, the largest fluctuation was seen for the chest examination where the EI ranged from 2560 to 2660, representing approximately an increase of 30% in radiation dose, despite consistent parameters. The fluctuations seen with the CR systems are most likely due to image processing delay, replacing of the imaging plate and calibration factors. Fluctuations in EI values may result in confusion to the clinician and unnecessary repeat examinations. The reliability of EI values as a feedback mechanism for CR is also questionable. (authors)

  2. Spatial variability of air dry bulb temperature and black globe humidity index in a broiler house during the heating phase / Variabilidade espacial de variáveis ambientais em um galpão avícola durante a fase de aquecimento

    Scientific Electronic Library Online (English)

    Patrícia F., Ponciano; Tadayuki, Yanagi Junior; Gabriel A. E S., Ferraz; João D., Scalon; Leonardo, Schiassi.

    2013-06-01

    Full Text Available A temperatura de bulbo seco do ar (t bs) bem como o índice de temperatura do globo negro e umidade (ITGU) exercem grande influência no desenvolvimento de frangos de corte durante a fase de aquecimento. Sendo assim, o objetivo deste trabalho foi analisar a estrutura e a magnitude da variabilidade esp [...] acial da t bs e ITGU, utilizando ferramentas da geoestatística por meio de análise de semivariograma e, ainda, a produção de mapas de isolinhas por meio de interpolação por krigagem. O experimento foi conduzido na mesorregião oeste de Minas Gerais, na primavera de 2010, em um galpão comercial com sistema de aquecimento constituído de duas fornalhas de aquecimento indireto do ar, durante os primeiros 14 dias de vida das aves. Os dados foram registrados em intervalos de cinco minutos, no período das 8 às 10 horas. As variáveis foram avaliadas por semivariograma ajustado pelo método da máxima verossimilhança restrita (REML), testando-se os modelos esférico e exponencial. Os mapas de krigagem foram produzidos baseados no melhor método de ajuste do semivariograma. As técnicas da geoestatística possibilitaram caracterizar a variabilidade da t bs e ITGU, permitindo a observação da dependência espacial. Além disso, com a utilização da geoestatística e dos mapas de distribuição, pode-se identificar falhas no sistema de aquecimento, em regiões do galpão que poderiam vir a prejudicar o desenvolvimento dos pintinhos. Abstract in english The air dry-bulb temperature (t db),as well as the black globe humidity index (BGHI), exert great influence on the development of broiler chickens during their heating phase. Therefore, the aim of this study was to analyze the structure and the magnitude of the t db and BGHI spatial variability, usi [...] ng geostatistics tools such as semivariogram analysis and also producing kriging maps. The experiment was conducted in the west mesoregion of the states of Minas Gerais in 2010, in a commercial broiler house with heating system consisting of two furnaces that heat the air indirectly, in the firsts 14 days of the birds' life. The data were registered at intervals of five minutes in the period from 8 a.m. to 10 a.m. The variables were evaluated by variograms fitted by residual maximum likelihood (REML) testing the Spherical and Exponential models. Kriging maps were generated based on the best model used to fit the variogram. It was possible to characterize the variability of the t db and BGHI, which allowed observing the spatial dependence by using geostatistics techniques. In addition, the use of geostatistics and distribution maps made possible to identify problems in the heating system in regions inside the broiler house that may harm the development of chicks.

  3. Determining Weight for Multicriteria Indexes

    Directory of Open Access Journals (Sweden)

    Abdul Aziz Jemain

    2004-06-01

    Full Text Available This paper discusses methods determining weight for each criterion used in the development of an index representing social indicators. Examples to show computing for weights are also given. Data for percent of household in all districts in the country, obtained from 1991 census, of that owned defined facilities such as car, radio, television, telephone, washing machine, and air-condition are used as example how such weights were computed

  4. Determining Weight for Multicriteria Indexes

    OpenAIRE

    Abdul Aziz Jemain

    2004-01-01

    This paper discusses methods determining weight for each criterion used in the development of an index representing social indicators. Examples to show computing for weights are also given. Data for percent of household in all districts in the country, obtained from 1991 census, of that owned defined facilities such as car, radio, television, telephone, washing machine, and air-condition are used as example how such weights were computed

  5. Estimating the Mean Annual Surface Air Temperature at Armagh Observatory, Northern Ireland, and the Global Land-Ocean Temperature Index for Sunspot Cycle 24, the Current Ongoing Sunspot Cycle

    Science.gov (United States)

    Wilson, Robert M.

    2013-01-01

    As noted by Gray et al., Sir William Herschel was the first to suggest a possible close connection between the Sun and the Earth’s climate. The Sun, being the source of energy that impacts and drives the Earth’s climate system, displays a variety of changes over both short and long term time scales, the most obvious examples being the somewhat regular waxing and waning of sunspots with time (i.e., the sunspot cycle (SC)), first described by Samuel Heinrich Schwabe, a German apothecary and amateur astronomer who observed the Sun from Dessau, Germany, and the now well established variation of the Sun’s irradiance over the SC. Other factors related to the SC have been linked to changes in climate as well. Some of these other factors include the role of cosmic rays and the solar wind (i.e., the geomagnetic cycle) on climate, as well as the apparent close association between trends in global and northern hemispheric temperature and the length of the SC, although some investigators have described the inferred association between climate and, in particular, SC length as now being weak. More recently, Solheim et al. have reported on the relation between SC length and the average temperature in the same and immediately following SC for a number of meteorological stations in Norway and in the North Atlantic region. They noted that while they found no significant trend (correlation) between SC length and the average temperature when measured for the same cycle, in contrast, they found a significant negative trend when SC length was compared with the following cycle’s average temperature. From this observation, they suggested that average northern hemispheric temperature during the present ongoing SC (SC24) will be lower by about 0.9 °C than was seen in SC23 (spanning 1996–2007, based on yearly averages of sunspot number (SSN), and onset for SC24 occurring in 2008). The purpose of this Technical Publication (TP) is to examine the annual variations of the Armagh surface air temperature (ASAT) and the Global Land-Ocean Temperature Index (GLOTI) in relation to SSN and the SC in order to determine their likely values during SC24. Hence, it may provide insight as to whether solar forcing of global temperature is now lessening as a contributor to global warming, thereby indicating a possible cooling in the near term immediate future that potentially could ameliorate the effect of increased anthropogenic warming.

  6. ZZ DLC-14 AIR, Group Constant Library of Secondary Gamma Transport in Air for ANISN Calculation

    International Nuclear Information System (INIS)

    1 - Nature of physical problem solved: Format: ANISN, DOT, MORSE (FIDO format); Number of groups: 22 neutron / 18 gamma-ray; Nuclides: air; Origin: ENDF/B for neutron cross sections, DLC-4/HPIC for gamma-ray and DLC-12/POPLIB for secondary gamma-ray production. Weighting spectrum: 1/E for neutron cross sections. The basic idea behind the distribution of this ANISN input data is to allow potential users to repeat the ANISN calculations reported in ref. (1). It is felt that it will be more economical to repeat the calculations rather than to distribute the results of the Straker-Gritzner (1) calculations. However, the cross section part of the data can actually be used in DOT or MORSE or any transport code which will accept input cross section in the FIDO format. 2 - Method of solution: The sample input data for ANISN are for a P5, S16 calculation of the transport of neutrons and secondary gamma-rays from a 12.2 to 15 MeV point neutron source in an infinite air medium. The source is actually uniformly distributed in the first interval (500 cm radius) of a spherical medium of air with radius 3005 meters. The problem is set up for calculating various 'detector responses' by means of the 'activity' option available with ANISN. This is accomplished by providing a cross section table for a 'material' which has detector responses in certain table positions. Then the inclusion of appropriate input data for 22$ and 23$ arrays causes the group fluxes to be multiplied by the group response function values to give the desired answer. The neutron detector responses calculated by this sample problem are Henderson tissue dose, Snyder-Neufeld dose, tissue kerma, and air kerma. The gamma-ray response functions calculated are Henderson tissue dose and air kerma. The neutron cross sections were first reduced from point data from ENDF/B to a 104 fine group structure with a modified version of CSP, assuming a 1/E weighting factor. The gamma-ray data were reduced from point data from DLC-4/HPIC to an 18 group structure using MUG. The POPOP-4 code was used to convert secondary gamma-ray production data from DLC-12/POPLIB to neutron-to-gamma-ray group transfer cross sections. The coupled set (104 neutron, 18 gamma-ray groups) was then collapsed to 22 neutron and 18 gamma-ray groups with ANISN, using as the weighting function the spectrum from a spatially uniform source of 14 MeV neutrons in an infinite air medium with a density of 1.11 mg/cc. The resulting data are coupled macroscopic multigroup, P5 expansion cross sections for air punched on cards and suitable for input to the ANISN code

  7. Air quality indices : a review

    International Nuclear Information System (INIS)

    Pollution Probe presents some background information that will help in the development of a national Air Quality Index (AQI) in Canada. This report examines the issues that should be addressed in revising the national Index of the Quality of Air (IQUA) or creating a new national Air Quality Index. The IQUA was devised in 1976 and provides Canadians with real-time information on the state of community air quality by including major pollutants and their synergies. It is currently being used for air quality management plans and air quality alert systems. At the same time that the IQUA was devised, the United States Environmental Protection Agency (US EPA) produced a parallel air quality index known as the Pollution Standard Index (PSI) which incorporated 5 criteria pollutants (particulate matter, sulphur dioxide, carbon monoxide, nitrogen oxide and ground level ozone) for which national health-based standards were devised. In 1999, the US EPA renamed their index the Air Quality Index (AQI) and made revisions to the primary health-based national ambient air quality standards for ground-level ozone and particulate matter. Separate values for PM2.5 and PM10 were incorporated and mandatory reporting was required for metropolitan areas with populations of 350,000 or more. Similarly, the IQUA has undergone major developments that affect the validity of the index, including: rejection by the Working Group on Air Quality Objectives and Guidelines of the previous maximum desirable and maximum acceptable air quality criteria, recognition that standards for many of the contaminants are outdated, developing more sensitive instrumentation for real-time monitoring of contaminants. This report also describes the use of the national short term Air Quality Index by provincial, territorial and local authorities in Canada. Pollution Probe recommends setting up a mechanism to review and revise IQUA on a regular basis that would incorporate governments, the medical profession, special public interest groups, as well as environmental and industrial interest groups. It also recommends that new ways should be developed to facilitate a comparison between IQUA and AQI readings with those for AQI in the United States, especially in border communities. 7 tabs

  8. EJSCREEN Indexes 2015 Public

    Data.gov (United States)

    U.S. Environmental Protection Agency — There is an EJ Index for each environmental indicator. There are eight EJ Indexes in EJSCREEN reflecting the 8 environmental indicators. The EJ Index names are:...

  9. EJSCREEN Indexes 2015 Internal

    Data.gov (United States)

    U.S. Environmental Protection Agency — There is an EJ Index for each environmental indicator. There are 12 EJ Indexes in EJSCREEN reflecting the 12 environmental indicators. The EJ Index names are:...

  10. Refractive index of plant cell walls

    Science.gov (United States)

    Gausman, H. W.; Allen, W. A.; Escobar, D. E.

    1974-01-01

    Air was replaced with media of higher refractive indices by vacuum infiltration in leaves of cucumber, blackeye pea, tomato, and string bean plants, and reflectance of noninfiltrated and infiltrated leaves was spectrophotometrically measured. Infiltrated leaves reflected less light than noninfiltrated leaves over the 500-2500-nm wavelength interval because cell wall-air interfaces were partly eliminated. Minimal reflectance should occur when the average refractive index of plant cell walls was matched by the infiltrating fluid. Although refractive indices that resulted in minimal reflectance differed among the four plant genera, an average value of 1.425 approximates the refractive index of plant cell walls for the four plant genera.

  11. Estimation of entrance dose on chest radiographs according to the exposure index on Computerized Radiology System: preliminary results; Estimativa de dose de entrada a partir do indice de exposicao em sistema CR: resultados preliminares

    Energy Technology Data Exchange (ETDEWEB)

    Donomai, Luana Kaoru; Jornada, Tiago da Silva; Daros, Kellen Adriana Curci, E-mail: luana.donomai@gmail.com, E-mail: tiagosjornada@gmail.com, E-mail: daros.kellen@unifesp.br [Universidade Federal de Sao Paulo (UNIFESP), Sao Paulo, SP (Brazil)

    2014-07-01

    Digital radiology has improved image quality in radiographs in comparison to screen/film systems though the visual control of the quantity of radiation involved on these exams became more demanding due to the low perception of over and underexposed images. Therefore, this study aims to analyze the exposure index (EI) from chest examinations and relate them to the entrance skin dose. Indices from 29 patients and kerma entrance dose were correlated. A correlation coefficient equal to 0,6881 was calculated. EI and entrance dose are correlated positive and moderately, indicating the relevance to deepen the subject. (author)

  12. Characterization of the new free-air primary standard for low-energy X-rays at CMI

    International Nuclear Information System (INIS)

    In 2011 a decision was made by Czech Metrology Institute to build a free-air ionization chamber (FAC) intended to be used as a primary standard of air kerma rate for low-energy X-rays (photon energy below 50 keV, including mammography X-ray qualities) in order to replace the currently used secondary ionization chamber and to decrease the uncertainty of air kerma reference value. In the period 2011–2012, the FAC has been designed, manufactured and put into operation. Its performance was tested using a calibrated secondary chamber and then by an informal comparison with a national primary standard of BEV (Austria). Physical characteristics of the FAC are described and individual correction factors are discussed focusing on computational methods utilized in their estimation. Summary of the correction factors with the uncertainty budget is presented. - Highlights: • A new primary standard for low-energy X-ray beam constructed at CMI. • Correction factors calculated by MCNPX simulations. • The chamber performance tested by an informal comparison with BEV (Austria). • The chamber considered ready for key comparison and standardization of X-ray beams

  13. CHEMICAL AND BIOLOGICAL AIR POLLUTANTS, AS PARAMETERS OF COMPLEX AIR QUALITY INDICES

    OpenAIRE

    TEKLA EÖTVÖS; LÁSZLÓ MAKRA

    2007-01-01

    Human health is essentially influenced by air quality. Atmospheric air in residential areas contains many pollutants. The monitoring and the plain publishing of the measured values are important both for the authorities and the public. Air quality is often characterized by constructing air quality indices, and these indices are used to inform the public. The construction of an advanced air quality index is usually done by averaging the measured data usually in time and space; hereby important...

  14. SOIL-RAD - A computer program to calculate air kerma, ambient dose rate and effective dose rate due to photons emitted by radionuclides distributed in soil or on the soil-air surface

    OpenAIRE

    Blaauboer RO

    2012-01-01

    In verschillende onderzoeken is er behoefte aan een geautomatiseerde methode voor het bepalen van de dosis ten gevolge van externe bestraling door radionucliden in en op de bodem. Hierbij kan gedacht worden aan migratie van fallout in de bodem, berekenen van de afschermende werking van de bodem bij het opbrengen van een afdeklaag over een laag ertsafval en het dosistempo door de natuurlijke aanwezigheid van radionucliden. In het kader van een onderzoek naar het gebruik...

  15. Supersymmetry and index theory

    International Nuclear Information System (INIS)

    The author presents information mainly concerned with the fact that many of the ingredients and results in index theory have very simple analogs in supersymmetric quantum mechanical systems so that using elementary quantum mechanics one can obtain new proofs of the Atiyah-Singer index theorem and related results. Simple ideas on index theorems and characteristic classes are reviewed; simple results on fermion functional integrals are outlined; supersymmetric quantum mechanical systems which appear naturally in dealing with index problems are analyzed; proof of the classical index theorem is presented; the character valued index theorem is derived; and applications of the methods developed here for the computation of anomalies are presented

  16. Simulation of Iodine-125 seeds photon spectra in the air by using the Monte Carlo method

    International Nuclear Information System (INIS)

    Viewing the characteristics of the construction of I-125 seed sources, the low energy of the I-125 photons spectra and the large anisotropy of these photons energy fluence, this paper presents a study of those parameters and their influence on the dose calculations during the sources implant, and also the results of the simulation by using the EGS4 Monte Carlo code for the IMC.6711 I-125 seed photon model, produced by the Amersham Healthcare and Instituto de Pesquisas Energeticas da Comissao Nacional de Energia Nuclear. The intensity of the kerma in the air has been calculated based on the photon fluencies for distances ranging from the source surface to 5 cm in air

  17. UV Index Widget

    Data.gov (United States)

    U.S. Environmental Protection Agency — The UV Index Widget displays the ultraviolet (UV) Index providing a daily forecast of the expected risk of overexposure to the sun for a user-specified area of...

  18. Fundamental data on environmental gamma-ray fields in the air due to sources in the ground

    International Nuclear Information System (INIS)

    This report documents the extensive results of calculations of gamma-ray fields due to sources distributed in the ground. Air kerma per unit source density at 12 heights up to 300 m above the ground was calculated using a Monte Carlo method for monoenergetic plane sources in and on the ground and for natural radionuclides uniformly distributed in the ground. In case of plane sources, calculations were performed for 18 photon energies from 10 keV to 5 MeV and for 22 source depths expressed in mass per unit area ranging from 0 to 200 g/cm2. For natural nuclides, the whole lines compiled in a recent nuclear data file were taken into account. With respect to kerma in air and fluence of primary photon, the whole calculated results are shown in this report. For double-differential gamma-ray fields, several heights and source depths were selected to demonstrate the features. The calculated data for different soil compositions in energy range up to 100 keV were also shown to give the measure of the effect of soil compositions. (author)

  19. Air Pollution

    Science.gov (United States)

    ... forms air pollution, it's also called smog. Some air pollutants are poisonous. Inhaling them can increase the chance you'll have health problems. People with heart or lung disease, older adults and children are at greater risk from air pollution. Air pollution isn't just outside - the ...

  20. Glycemic Index and Diabetes

    Science.gov (United States)

    ... Text Size: A A A Listen En Español Glycemic Index and Diabetes The glycemic index, or GI, measures how a carbohydrate-containing food ... of Carbohydrates Carbohydrate Counting Make Your Carbs Count Glycemic Index and Diabetes Sugar and Desserts Sugar Alcohols Low- ...

  1. Clean Air Markets - Quick Facts and Trends

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Quick Facts and Trends module is part of a suite of Clean Air Markets-related tools that are accessible at http://camddataandmaps.epa.gov/gdm/index.cfm. The...

  2. Stamping Forming Quality Index

    Directory of Open Access Journals (Sweden)

    Yanping Zheng

    2013-01-01

    Full Text Available The study proposes that stamping forming quality index should include defect quality index and thickness variation uniformity quality index and different types of stamping parts focus on different defect quality index .Moreover, the fracture and wrinkle quality index can be demonstrated by the distance between the major strain of the simulation unit and the critical curve of the fracture and wrinkle trend in FLD, while thickness variation uniformity quality index can be expressed by variance of sheet metal thinning rate. It takes the automobile back plate reinforcement as the example, select stamping quality index as optimization objectives and constraint conditions based on numerical simulation technology, then apply the technical means that contain with orthogonal test design, neural network and genetic algorithm to optimize the process variables. The result indicates that the method of this study is feasible and effective and has application value in engineering.

  3. EJSCREEN Supplementary Indexes 2015 Internal

    Data.gov (United States)

    U.S. Environmental Protection Agency — There are 60 supplementary EJ Indexes in EJSCREEN that are divided into 5 categories: EJ Index with supplementary demographic index, Supplementary EJ Index 1 with...

  4. A Tourism Conditions Index

    OpenAIRE

    Chang, Chia-lin; Hsu, Hui-Kuang; McAleer, Michael

    2014-01-01

    This paper uses monthly data from April 2005 to August 2013 for Taiwan to propose a novel tourism indicator, namely the Tourism Conditions Index (TCI). TCI accounts for the spillover weights based on the Granger causality test and estimates of the multivariate BEKK model for four TCI indicators to predict specific tourism and economic environmental indicators for Taiwan. The foundation of the TCI is the Financial Conditions Index (FCI), which is derived from the Monetary Conditions Index (MCI...

  5. Monitoring of Air Polution by Using Fuzzy Logic

    OpenAIRE

    Dr. Gopal Upadhyaya,; Mr. Nilesh Dashore

    2010-01-01

    The Air Quality Index is a simple and generalized way to describe the air quality in China, Hong Kong, Malaysia and now in India. Indian Air Quality Index (IND-AQI) is mainly a health related index with the descriptor words: “Good (0- 100)”, “Moderate (101-200 )”, “Poor (201-300)”, “Very Poor (301-400)”, “Severe (401-500)”. State Environment Protection Agency (SEPA ) is responsible for measuring the level of air pollution in China . In China the AQI is based on the level of 5 atmospheric poll...

  6. Supplement: Commodity Index Report

    Data.gov (United States)

    Commodity Futures Trading Commission — Shows index traders in selected agricultural markets. These traders are drawn from the noncommercial and commercial categories. The noncommercial category includes...

  7. Computaional Complexity Analysis on Water Quality Index

    OpenAIRE

    Anni Prabakaran & Dr. B. Poorna

    2012-01-01

    The computational algorithms are used to determine the features and applications from large data sets in real time environment. The computational applications are also used in environmental computing to evaluate the degree of air, water and sound pollutions and measures of prevention. The computational process of water quality index (WQI) is determined through analysis of water quality attributes. Though existing methods produced WQI with certain water quality attributes according to the natu...

  8. A Ventilation Index for Tropical Cyclones

    OpenAIRE

    Tang, Brian; Emanuel, Kerry Andrew

    2012-01-01

    An important environmental control of both tropical cyclone intensity and genesis is vertical wind shear. One hypothesized pathway by which vertical shear affects tropical cyclones is midlevel ventilation—or the flux of low-entropy air into the center of the tropical cyclone. Based on a theoretical framework, a ventilation index is introduced that is equal to the environmental vertical wind shear multiplied by the nondimensional midlevel entropy deficit divided by the potential intensity. The...

  9. Concurrency Control for Adaptive Indexing

    CERN Document Server

    Graefe, Goetz; Idreos, Stratos; Kuno, Harumi; Manegold, Stefan

    2012-01-01

    Adaptive indexing initializes and optimizes indexes incrementally, as a side effect of query processing. The goal is to achieve the benefits of indexes while hiding or minimizing the costs of index creation. However, index-optimizing side effects seem to turn read-only queries into update transactions that might, for example, create lock contention. This paper studies concurrency control in the context of adaptive indexing. We show that the design and implementation of adaptive indexing rigorously separates index structures from index contents; this relaxes the constraints and requirements during adaptive indexing compared to those of traditional index updates. Our design adapts to the fact that an adaptive index is refined continuously, and exploits any concurrency opportunities in a dynamic way. A detailed experimental analysis demonstrates that (a) adaptive indexing maintains its adaptive properties even when running concurrent queries, (b) adaptive indexing can exploit the opportunity for parallelism due ...

  10. Dow's chemical exposure index guide

    International Nuclear Information System (INIS)

    A number of events in the 1970's and 1980's impacted the course of process safety. Incidents such as Flixborough, Seveso, Three-Mile Island, and Bhopal are well known throughout industry and are recognized as examples of major disasters. Even though events leading up to these disasters were completely different they had one common element between them: a substance was released from a manufacturing unit, became airborne and presented a hazard of such magnitude as to place the safety of both employees and the surrounding public in jeopardy. As a result, industry became increasingly concerned regarding potential loss, in human and economic terms, as plants and equipment grew in size. The Flixborough incident raised the level of concern for process safety, particularly in terms of the hazards presented by fire and explosion. Seveso and Three-Mile Island emphasized the need to consider far-field exposure. The Bhopal incident created an urgent need to recognize and understand the expected downwind impact of potential releases of acutely toxic substances to the air. In order to meet this need, the Dow Chemical Company, a recognized leader in the area of safety and loss prevention, presented a Chemical Exposure Index in 1986. AIChE has recently published an updated version entitled Dow's Chemical Exposure Index Guide. 7 refs., 5 figs

  11. UV Index estimation from global radiation and total ozone observations in Azores.

    OpenAIRE

    Carvalho, Fernanda; Henriques, Diamantino; Fialho, Paulo

    2007-01-01

    The UV Index (UVI) is a public-oriented meteorological kind of information about the damaging ultraviolet radiation at the ground (Vaniceck et al., 1999). Its use begins to be so popular as temperatures highs, wind chill, fire risk index, air quality index and other meteorological indexes and parameters. A UVI scale was already defined by WHO (WHO, 2002) in order to provide a correspondence between UVI levels and protective measures to avoid damaging effects on humans. However, UVI is usually...

  12. Variation of transmittance spectra of porous antireflection coatings with index profile

    International Nuclear Information System (INIS)

    Transmittance spectra were calculated for single-layer coatings with the homogeneous refractive index, index profiles that increase monotonically with distance into the coating, and index profiles that rise in discrete steps. The calculations predict that large transmittance at tuned wavelengths can be obtained using any of these coating designs and known, porous silica coating materials. The spectral bandwidth of transmittance maxima increases when the index profile is altered from homogeneous to any profile whose index increases monotonically with thickness in the coating. Bandwidth is greatest for the linear-ramp coating whose index rises linearly from that of air to that of the substrate

  13. Synchrotron emission in air

    Science.gov (United States)

    Rafat, M. Z.; Melrose, D. B.

    2015-05-01

    A conventional astrophysical treatment of synchrotron emission is modified to include the refractive index of air, written as n = 1 + 1/(2? 02), with ?0 ? 1. The angular distribution of emission by an electron with Lorentz factor ? is broadened, from a range of |? - ?| ? 1/? in vacuo (? = emission angle, ? = pitch angle) to |? - ?| ? max{1/?, 1/?0} in air. The emission spectrum in air is almost unchanged from that in vacuo at sufficiently low frequencies and it is modified by extending to higher frequencies with increasing ?/?0 1. We interpret the enhanced high-frequency emission as Cerenkov-like, and attribute it to the formation of caustic surfaces that sweep across the observer; we use a geometric model based on Huygens construction to support this interpretation. The geometric model predicts that the so-called Cerenkov ring present at high frequencies may be circular, elliptical, or crescent shaped. In the astrophysical treatment of synchrotron emission, the dependence on azimuthal angle is lost in the expression for emissivity. A motivation for this investigation is the application to extensive air showers, and for this purpose the loss of azimuthal dependence is a limitation. We comment on methods to overcome this limitation. We show that when an observer can see emission from inside the Cerenkov cone, emission from outside the Cerenkov cone, on either side of it, arrives simultaneously; there are three emission times for a given observation time.

  14. National Death Index

    Data.gov (United States)

    U.S. Department of Health & Human Services — The National Death Index (NDI) is a centralized database of death record information on file in state vital statistics offices. Working with these state offices,...

  15. Regional Snowfall Index (RSI)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA's National Climatic Data Center is now producing the Regional Snowfall Index (RSI) for significant snowstorms that impact the eastern two thirds of the U.S....

  16. Arizona - Social Vulnerability Index

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Social Vulnerability Index is derived from the 2000 US Census data. The fields included are percent minority, median household income, age (under 18 and over...

  17. Vegetation Drought Response Index

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — VegDRI, short for Vegetation Drought Response Index, is a drought-monitoring tool developed by scientists at EROS in collaboration with the National Drought...

  18. Air lock

    International Nuclear Information System (INIS)

    The patent refers to an air lock system preferably for nuclear stations for the transport of heavy loads by means of a trolley on rails. For opening and closing of the air lock parts of the rails are removed, e.g. by a second rail system perpendicular to the main rails. (P.K.)

  19. Lattice Index Coding

    OpenAIRE

    Natarajan, Lakshmi; Hong, Yi; Viterbo, Emanuele

    2014-01-01

    The index coding problem involves a sender with K messages to be transmitted across a broadcast channel, and a set of receivers each of which demands a subset of the K messages while having prior knowledge of a different subset as side information. We consider the specific case of noisy index coding where the broadcast channel is Gaussian and every receiver demands all the messages from the source. Instances of this communication problem arise in wireless relay networks, sen...

  20. A Study on the Use of a Statistical Analysis Model to Monitor Air Pollution Status in an Air Quality Total Quantity Control District

    OpenAIRE

    Shu-Lung Kuo; Edward Ming-Yang Wu

    2013-01-01

    The air quality in Taiwan, at present, is determined by a pollution standard index (PSI) that is applied to areas of possible serious air pollution and Air Quality Total Quantity Control Districts (AQTQCD). Many studies, both in Taiwan and in other countries have examined the characteristics and levels of air pollution with PSI. This study uses air quality data collected from eight automatic air quality monitoring stations in an AQTQCD in central Taiwan and discusses the correlation between a...

  1. Recommended concentration limits of indoor air pollution indicators for requirement of acceptable indoor air quality

    Directory of Open Access Journals (Sweden)

    Wang J., Zhang X.

    2010-07-01

    Full Text Available Object and goals of indoor air pollution control with ventilation may influence improvement of indoor air quality, building energy consumption and even carbon emissions. Indicators of indoor air pollution caused by occupants-related sources and building-related sources were chosen based on sources emitting characteristics, pollutants composition, indicator choosing principles and indoor air pollution situation in China. Then the recommended concentration limits of indicators were given for unadapted and adapted persons according to logarithmic index evaluation method, combined with percentage of dissatisfaction and joint effect of indoor air pollution caused by these two kinds of sources.

  2. 2005 Environmental Sustainability Index (ESI)

    Data.gov (United States)

    National Aeronautics and Space Administration — The 2005 Environmental Sustainability Index (ESI) is a measure of overall progress towards environmental sustainability, developed for 146 countries. The index...

  3. Introduction of a Cooling-Fan Efficiency Index

    DEFF Research Database (Denmark)

    Schiavon, S.; Melikov, Arsen Krikor

    2009-01-01

    In a warm environment, air movement with elevated velocity is a well-known cooling strategy. The local air movement is typically generated by cooling fans (e.g., ceiling fan, table fans, etc.). Appearance, power input, and price are the main parameters considered today when purchasing cooling fans, while cooling capacity and efficiency of energy use are unknown. To address this knowledge gap, this paper introduces the cooling-fan efficiency (CFE) index, defined as the ratio between the cooling effect (measured with a thermal manikin) generated by the device and its power consumption. The index was determined for a ceiling fan, a desk fan, standing fan, and a tower fan in a real office at three room air temperatures and at different fan speed levels. The results reveal that the index is sensitive enough to identify differences in the performance of the cooling devices. A standard method for testing fan cooling effect and an index for determining fan efficiency, such as the CFE index proposed in this study, need to be developed. The cooling fans generate a nonuniform velocity field around occupants, which cannot be described with a single air-velociry value. Therefore, it is not clear how to apply in practice the recommended elevated velocities in warm environments presented in the present standards. The standards need to be revised.

  4. Neural computing thermal comfort index for HVAC systems

    International Nuclear Information System (INIS)

    The primary purpose of a heating, ventilating and air conditioning (HVAC) system within a building is to make occupants comfortable. Without real time determination of human thermal comfort, it is not feasible for the HVAC system to yield controlled conditions of the air for human comfort all the time. This paper presents a practical approach to determine human thermal comfort quantitatively via neural computing. The neural network model allows real time determination of the thermal comfort index, where it is not practical to compute the conventional predicted mean vote (PMV) index itself in real time. The feed forward neural network model is proposed as an explicit function of the relation of the PMV index to accessible variables, i.e. the air temperature, wet bulb temperature, globe temperature, air velocity, clothing insulation and human activity. An experiment in an air conditioned office room was done to demonstrate the effectiveness of the proposed methodology. The results show good agreement between the thermal comfort index calculated from the neural network model in real time and those calculated from the conventional PMV model

  5. Graded Index Microstructured Polymer Optical Fibers for Terahertz Applications

    OpenAIRE

    Ma, Tian; Markov, Andrey; Wang, Lili; Skorobogatiy, Maksim

    2014-01-01

    Graded index microstructured polymer optical fiber incorporating a specially designed air-hole array featuring variable air-hole diameters and inter-hole separation is proposed, fabricated and characterized in view of the fiber potential applications in low-loss, low-dispersion terahertz guidance. The proposed fiber features simultaneously low chromatic and intermodal dispersions, as well as low loss in the terahertz spectral range. We then experimentally demonstrate that pr...

  6. New share index to track progress of environmental industry

    International Nuclear Information System (INIS)

    This article discusses the work of the environmental finance house Imax Capital in persuading investors to invest in environmental industries. The development of the ET-50 Index by Impax Capital Asset Management to track progress of the environmental industry is reported, and the categories of the ET-50 including alternative energy generators and equipment providers, air and water pollution control, soil and site remediation, recycling and waste management, and environmental engineering and consulting are considered. The performance of the ET-50 Index, and the work of Impax and RER in the development of a dedicated renewable energy share index by are discussed

  7. Determination of the air attenuation and electronic loss for the free air concentric cylinders ionization chamber; Determinacao da atenuacao do ar e perda eletronica para a camara de ionizacao de ar livre de cilindros concentricos

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Hebert Pinto Silveira de

    2010-07-01

    Along the latest years, the LNMRI has been proceeding a continuous research work with a concentric cylinders type free air ionizing chamber (VICTOREEN, model 481), aiming to establish it as a new national standard, and, as a consequence, replace the worldwide accepted secondary standard, calibrated by PTB. Taking into account that the absolute determination of kerma in air with a free air ionizing chamber implies the acquirement of a number of correction factors. The main objective of the present work comprises the determination of the two factors, specifically, electronic loss (k{sub e}) and air attenuation (k{sub a}). The correction factors were obtained through mammography qualities reference spectrum, using Monte Carlo simulation method. The Penelope code was used in the simulation procedures. Simulations took place in two stages, the acquirement of specters related to the qualities of interest (mammography) with the x ray tube (Pantak, model HF160 e Panalytical, model XRF window), and the free-air ionization chamber. The data were compared to those related to the BIPM chamber, to electronic loss were not detected. The comparison between air attenuation factors was obtained data bellow 0.13%. (author)

  8. Air Abrasion

    Science.gov (United States)

    ... information you need from the Academy of General Dentistry Monday, October 12, 2015 About | Contact InfoBites Quick ... general dentist, who has been trained in restorative dentistry techniques, will perform any procedures that use air- ...

  9. Upgrading the Wiener index

    Directory of Open Access Journals (Sweden)

    PABLO PERUZZO

    2002-10-01

    Full Text Available The Wiener index W is the oldest molecular-graph-based structure-descriptor. It is defined as the sum of the distances of all pairs of vertices of the molecular graph G, where the distance is the number of edges in the shortest path connecting the respective vertices, and where G is the hydrogen-depleted molecular graph. This seemingly very simple topological index could be "upgraded" (a by using as the distance the sum of the bond lengths along the shortest path, or (b by using the Euclidean distance between the respective pairs of atoms. Each of these "upgraded" Wiener indices could be computed either (a for the hydrogen-depleted or (b for the hydrogen-filled molecular graph. We provide examples showing that none of the modifications (aa, (ab, (ba, (bb yields better results than the ordinary Wiener index, and that there is a very good linear correlation between W and its "upgraded" variants.

  10. Sustainability index for Taipei

    International Nuclear Information System (INIS)

    Sustainability indicators are an effective means of determining whether a city is moving towards sustainable development (SD). After considering the characteristics of Taipei, Taiwan, discussions with experts, scholars and government departments and an exhaustive literature review, this study selected 51 sustainability indicators corresponding to the socio-economic characteristic of Taipei City. Such indicators should be regarded as a basis for assessing SD in Taipei City. The 51 indicators are classified into economic, social, environmental and institutional dimensions. Furthermore, statistical data is adopted to identify the trend of SD from 1994 to 2004. Moreover, the sustainability index is calculated for the four dimensions and for Taipei as a whole. Analysis results demonstrate that social and environmental indicators are moving towards SD, while economic and institutional dimensions are performing relatively poorly. However, since 2002, the economic sustainability index has gradually moved towards SD. Overall, the Taipei sustainability index indicates a gradual trend towards sustainable development during the past 11 years

  11. Air Pollution and Cardiovascular System

    Directory of Open Access Journals (Sweden)

    Ejder Kardesoglu

    2011-02-01

    Full Text Available Air pollution is one of the environmental problems that threaten the public health. The air is a gas mixture. Air pollution is defined as the existence in the amount of pollutants harmful to humans and other organisms in the atmosphere as a result of the natural or human activity thereby changing to the gas rates in the air. The negative effects of pollution-causing particles on the health are closely related to the chemical structure of particles, whether causing a fibrotic reaction, whether having an amorphous shape and the aerodynamic diameters of particles. The particles larger than 10 microns in aerodynamic diameter can not reach up to the alveoli, and can be removed by mucociliary system. If the particles are smaller than 10 microns, these particles can reach to the alveoli, and are closely associated with the cardiovascular mortality and morbidity. The concentration of these particles (PM10 is used as an indicator of pollution, and creates the basis for air quality index. Air pollution has several negative effects such as blood pressure changes, atherosclerosis, endothelial dysfunction, autonomic dysfunction, inflammation, oxidative stress etc. In this review, the effects of air pollution on the cardiovascular system will be examined, and the importance of this issue will be emphasized. [TAF Prev Med Bull 2011; 10(1.000: 97-106

  12. Structure and Implementation of Multiuser Collaborative in Duty Cycling Control of Central Air Conditioning

    OpenAIRE

    Chen, Cheng

    2014-01-01

    Proposed optimization model of duty cycling control in central air conditioning based on human comfort index. The human comfort index is incorporated into the process of duty cycling control in central air conditioning, and we found that the range of reducing air conditioning load is affected by temperature and humidity parameters. When ensure the premise of human comfort, there exists a maximum volume of reducing air conditioning load. The changing of indoor and outdoor temperature determine...

  13. A comparison of in-air and in-water calibration of a dosimetry system used for radiation dose assessment in cancer therapy

    Directory of Open Access Journals (Sweden)

    Arshed Waheed

    2010-01-01

    Full Text Available An accurate calibration of the therapy level radiation dosimetry system has a pivotal role in the accuracy of dose delivery to cancer patients. The two methods used for obtaining a tissue equivalent calibration of the system: air kerma calibration and its conversion to a tissue equivalent value (absorbed dose to water and direct calibration of the system in a water phantom, have been compared for identical irradiation geometry. It was found that the deviation between the two methods remained within a range of 0% to ±1.7% for the PTW UNIDOS dosimetry system. This means that although the recommended method is in-water calibration, under exceptional circumstances, in-air calibration may be used as well.

  14. Fourth Indexing Course

    Directory of Open Access Journals (Sweden)

    Director DESIDOC

    1982-04-01

    Full Text Available The fourth training course in 'Indexing' was organised by DESIDOC at Metcalfe House, Delhi from 24 Feb to 6 Mar 1982. The course was intended for information personnel of DRDO Labs/Estts located in the north zone. The curriculum covered various aspects of indexing techniques and systems including computer processing. Besides the lectures and practical assignments, audiovisual demonstration on NTIS services was also screened. Visits to DRDO Computer Centre to familiarise the participants with the working of the computer, and INSDOC/National Science Library were also arranged.

  15. Indexing Moving Points

    DEFF Research Database (Denmark)

    Agarwal, Pankaj K.; Arge, Lars Allan; Erickson, Jeff

    2003-01-01

    We propose three indexing schemes for storing a set S of N points in the plane, each moving along a linear trajectory, so that any query of the following form can be answered quickly: Given a rectangle R and a real value t, report all K points of S that lie inside R at time t. We first present an indexing structure that, for any given constant >0, uses O(N/B) disk blocks and answers a query in O((N/B)1/2+ +K/B) I/Os, where B is the block size. It can also report all the points of S that lie insi...

  16. Harary index - Twelve years later

    OpenAIRE

    Lu?i?, Bono; Mili?evi?, Ante; Nikoli?, Sonja; Nenad TRINAJSTI?

    2002-01-01

    A modification of the Harary index, denoted by H and introduced twelve years ago, is proposed. Unlike the original index, this index, called the modified Harary index and denoted by (m)H, consists of two parts: the first relates to greater contributions of outer bonds and the second to smaller contributions of inner bonds of an alkane, which is in accordance with the chemists' intuition. The Wiener index W Harary index and modified Harary index are compared in the structure-property modeling ...

  17. An Admissions Accountability Index

    Science.gov (United States)

    Brailey, Lester G.; Jacobs, Les

    1974-01-01

    CUNY's comprehensive data base and its geographic and educational parameters make possible the computation of an Admissions Accountability Index built on an input-output (hours-applications) ratio. It helps staff determine which high schools need and deserve more time and service, and helps high-school advisers compare their results with similar…

  18. Graded-index magnonics

    Science.gov (United States)

    Davies, C. S.; Kruglyak, V. V.

    2015-10-01

    The wave solutions of the Landau-Lifshitz equation (spin waves) are characterized by some of the most complex and peculiar dispersion relations among all waves. For example, the spin-wave ("magnonic") dispersion can range from the parabolic law (typical for a quantum-mechanical electron) at short wavelengths to the nonanalytical linear type (typical for light and acoustic phonons) at long wavelengths. Moreover, the long-wavelength magnonic dispersion has a gap and is inherently anisotropic, being naturally negative for a range of relative orientations between the effective field and the spin-wave wave vector. Nonuniformities in the effective field and magnetization configurations enable the guiding and steering of spin waves in a deliberate manner and therefore represent landscapes of graded refractive index (graded magnonic index). By analogy to the fields of graded-index photonics and transformation optics, the studies of spin waves in graded magnonic landscapes can be united under the umbrella of the graded-index magnonics theme and are reviewed here with focus on the challenges and opportunities ahead of this exciting research direction.

  19. Glycemic Index Values Database

    Science.gov (United States)

    NCI has developed a listing of Glycemic Index (GI) values for individual foods. Food codes from the USDA Continuing Survey of Food Intakes of Individuals (CSFII) are used as a reference. This file provides GI values for those foods consumed by adults and queried on the DHQ or other FFQs used at NCI.

  20. Well Being Index

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Gallup-Healthways Well-Being Index is the first-ever daily assessment of U.S. residents' health and well-being. By interviewing at least 1,000 U.S. adults every...

  1. Scientific Journal Indexing

    Directory of Open Access Journals (Sweden)

    Getulio Teixeira Batista

    2007-08-01

    Full Text Available It is quite impressive the visibility of online publishing compared to offline. Lawrence (2001 computed the percentage increase across 1,494 venues containing at least five offline and five online articles. Results shown an average of 336% more citations to online articles compared to offline articles published in the same venue. If articles published in the same venue are of similar quality, then they concluded that online articles are more highly cited because of their easier access. Thomson Scientific, traditionally concerned with printed journals, announced on November 28, 2005, the launch of Web Citation Index™, the multidisciplinary citation index of scholarly content from institutional and subject-based repositories (http://scientific.thomson. com/press/2005/8298416/. The Web Citation Index from the abstracting and indexing (A&I connects together pre-print articles, institutional repositories and open access (OA journals (Chillingworth, 2005. Basically all research funds are government granted funds, tax payer’s supported and therefore, results should be made freely available to the community. Free online availability facilitates access to research findings, maximizes interaction among research groups, and optimizes efforts and research funds efficiency. Therefore, Ambi-Água is committed to provide free access to its articles. An important aspect of Ambi-Água is the publication and management system of this journal. It uses the Electronic System for Journal Publishing (SEER - http://www.ibict.br/secao.php?cat=SEER. This system was translated and customized by the Brazilian Institute for Science and Technology Information (IBICT based on the software developed by the Public Knowledge Project (Open Journal Systems of the British Columbia University (http://pkp.sfu.ca/ojs/. The big advantage of using this system is that it is compatible with the OAI-PMH protocol for metadata harvesting what greatly promotes published articles visibility. Currently, there are 687 conformably registered repositories in OAI. The Public Knowledge Project – Open Archives Harvester2. lists Ambi-Água: http://pkp.sfu.ca/harvester2/demo/index.php/browse/ index/677. At the OAI base the URL of Ambi-Água is http://www.agro.unitau.br/ seer/index.php/ambi-agua/oai?verb=Identify. Therefore, all Service Providers are automatically capable of harvesting metadata from Ambi-Água articles.

  2. Air surveillance

    Energy Technology Data Exchange (ETDEWEB)

    Patton, G.W.

    1995-06-01

    This section of the 1994 Hanford Site Environmental Report summarizes the air surveillance and monitoring programs currently in operation at that Hanford Site. Atmospheric releases of pollutants from Hanford to the surrounding region are a potential source of human exposure. For that reason, both radioactive and nonradioactive materials in air are monitored at a number of locations. The influence of Hanford emissions on local radionuclide concentrations was evaluated by comparing concentrations measured at distant locations within the region to concentrations measured at the Site perimeter. This section discusses sample collection, analytical methods, and the results of the Hanford air surveillance program. A complete listing of all analytical results summarized in this section is reported separately by Bisping (1995).

  3. Air Quality of Beijing and Impacts of the New Ambient Air Quality Standard

    Directory of Open Access Journals (Sweden)

    Wei Chen

    2015-08-01

    Full Text Available Beijing has been publishing daily reports on its air quality since 2000, and while the air pollution index (API shows that the air quality has improved greatly since 2000, this is not the perception of Beijing’s residents. The new national ambient air quality standard (NAAQS-2012, which includes the monitoring of PM2.5, has posed stricter standards for evaluating air quality. With the new national standard, the air quality in Beijing is calculated using both NAAQS-2012 and the previous standard. The annual attainment rate has dropped from 75.5% to 50.7%. The spatial analysis of air quality shows that only a background station could attain the national standard, while urban and suburban stations exceed the national standard. Among the six pollutants included in the NAAQS-2012, PM2.5 is the major contributor to the air quality index (AQI comparing with the five other pollutants. The results indicate that under previous NAAQS without PM2.5 monitoring, the air quality has improved greatly in the past decade.  By considering PM2.5, the air quality attainment has dropped greatly. Furthermore, a great effort is needed for local government to bring down the PM2.5 concentration.

  4. Air refractive index measurement using low-coherence interferometry.

    Czech Academy of Sciences Publication Activity Database

    Pikálek, Tomáš; Buchta, Zden?k

    2015-01-01

    Ro?. 54, ?. 16 (2015), s. 5024-5020. ISSN 1559-128X R&D Projects: GA MŠk ED0017/01/01; GA MŠk(CZ) LO1212; GA ?R GB14-36681G Institutional support: RVO:68081731 Keywords : updated edlen equantion * frequency combs * laser * refractometry Subject RIV: BH - Optics, Masers, Laser s Impact factor: 1.784, year: 2014

  5. City Noise-Air : an environmental quality index for cities

    OpenAIRE

    Silva, Lígia Torres; Mendes, José F. G.

    2012-01-01

    Global population growth has led to an increase of the number of people living in urban areas. As a consequence, stresses on space, ecosystems, infrastructures, facilities and personal lifestyles have been enhanced. Problems related to the quality of life in cities are increasingly relevant, especially with regard to environmental issues. Domestic and industrial sources and, primarily, motorised traffic are responsible for pollutant emissions and noise that decisively affect life ...

  6. Air pollution

    International Nuclear Information System (INIS)

    The air pollution results from the combustion of petroleum products, natural gas, coal, wastes and transports. Some compounds are considered as particularly pollutants: the carbon monoxide, the nitrogen oxides, the tropospheric ozone and the sulfur dioxides. Their environmental and biological effects are described. The present political guide lines concerns the combustion plants, the ozone, the wastes incineration and the vehicles emissions. The aim is at some future date to control the air quality, to reduce the volatile organic compounds emissions and to limit the sulfur rate of some petroleum products. (O.L.)

  7. Variación espacial de la exposición a contaminación atmosférica en la ciudad de Valencia y su relación con un índice de privación / The spatial distribution of population exposure to outdoor air pollution in Valencia (Spain) and its association with a privation index

    Scientific Electronic Library Online (English)

    Marisa, Estarlich; Carmen, Iñiguez; Ana, Esplugues; Enrique, Mantilla; Òscar, Zurriaga; Andreu, Nolasco; Ferran, Ballester.

    2013-04-01

    Full Text Available Objetivo: Evaluar la variación espacial de la exposición a dióxido de nitrógeno (NO2) en la ciudad de Valencia y su relación con la privación socioeconómica y la edad. Métodos: La población por sección censal (SC) procede del Instituto Nacional de Estadística. Los niveles de NO2 se midieron en 100 p [...] untos del área de estudio, mediante captadores pasivos, en tres campañas entre 2002 y 2004. Se utilizó regresión por usos del suelo (LUR) para obtener el mapa de los niveles de NO2. Las predicciones del LUR se compararon con las proporcionadas por: a) el captador más cercano de la red de vigilancia, b) el captador pasivo más cercano, c) el conjunto de captadores en un entorno y d) kriging. Se asignaron niveles de contaminación para cada SC. Se analizó la relación entre los niveles de NO2, un índice de privación con cinco categorías y la edad (>65 años). Resultados: El modelo LUR resultó el método más preciso. Más del 99% de la población superó los niveles de seguridad propuestos por la Organización Mundial de la Salud. Se encontró una relación inversa entre los niveles de NO2 y el índice de privación (? = -2,01?g/m³ en el quintil de mayor privación respecto al de menor, IC95%: -3,07 a -0,95), y una relación directa con la edad (? = 0,12?g/m³ por incremento en unidad porcentual de población >65 años, IC95%: 0,08 a 0,16). Conclusiones: El método permitió obtener mapas de contaminación y describir la relación entre niveles de NO2 y características sociodemográficas. Abstract in english Objective: To evaluate spatial variation in exposure to nitrogen dioxide (NO2) air pollution in the city of Valencia, Spain, and its association with socioeconomic deprivation and age. Methods: Census tract population data were obtained from the National Statistics Institute of Spain. Outdoor NO2 wa [...] s monitored in 100 sites in the study area, through the use of passive samplers, in three campaigns between 2002 and April 2004. Land use regression (LUR) was used to obtain a map of NO2 levels. The LUR predictions were compared with the NO2 level obtained by: a) the nearest sampler of the monitoring network, b) the nearest passive sampler, c) the mean distance-weighted levels of the samplers in the neighborhood, and d) the NO2 level obtained by using Kriging. For each census tract, the NO2 levels were obtained. The association of NO2 air pollution exposure with population age (>65 years) and the 5-category deprivation index was analyzed. Results: The LUR models showed less error than the other prediction methods. The safety levels proposed by the World Health Organization were exceeded in more than 99% of the population. An inverse relationship was found between NO2 levels and the deprivation index (? = -2.01?g/m³ in the most deprived quintile compared with lower deprivation, 95%CI: -3.07; -0.95) and a direct relationship was found with age (? = 0.12?g/m³ per unit increase in percentage of the population > 65 years, 95%CI: 0.08; 0.16). Conclusions: The method allowed pollution maps to be obtained and the association between NO2 levels and sociodemographic characteristics to be described.

  8. Inhalation dose due to presence of 131I in air above septic tank system of an endocrinology hospital

    International Nuclear Information System (INIS)

    We present here measurements of the 131I concentration for both: Gaseous and aerosol fraction of 131I in the air above the septic tank containing wastes from medical application of this isotope. Aerosols were collected using air filters, whereas gaseous forms of iodine were trapped in KI impregnated charcoal double layer cartridge. Besides an active method (pumping of the air through system of filters) an attempt for using a passive method (charcoal traps) for monitoring of radio-iodine is described. For better characterisation of a site the external kerma was determined by means of G - M and TLD techniques as well as the activity kept in the septic tank was measured by gamma spectrometry. Results show that the activity of the aerosol fraction can be neglected compared to that of the gaseous fraction. He measured activity of air is low, on the level of 1 Bq m-3, even during simulated failure of the ventilation system. Estimated inhalation dose for the serviceman of septic tanks is low (?10%) compared with external dose obtained by such person due to gamma radiation from the tank (on the level ?500 nSv h-1). Therefore, the concept of passive monitoring of the iodine in air was abandoned. Also estimated is the efficiency of 131I reduction by a charcoal filter of the ventilation system and 131I input to the environment by the ventilation chimney. (authors)

  9. Air pollution

    International Nuclear Information System (INIS)

    Air pollution has accompanied and developed with the industrial age, since its beginnings. This very complete review furnishes the toxicological data available for the principal pollutants and assesses the epidemiologic studies thus far conducted. It also describes European regulations and international commitments for the reduction of emissions. (author)

  10. Towards Cryptocurrency Index

    OpenAIRE

    Trimborn, Simon

    2015-01-01

    In dieser Thesis wird ein Marktindex konstruiert, wobei neu entwickelte Methoden für solch eine Aufgabe verwendet werden. Die Entscheidung über die Anzahl der Indexteilnehmer wird mithilfe des AIC und BIC Kriteriums getroffen und die Liquiditätsregel wird auf Grundlage der BIS Umfrage ermittelt. Dieser neu entwickelte Index, CRIX, wird dann benutzt, um den Kryptowährungsmarkt gegen Bitcoins und andere Märkte zu vergleichen. Es wurde herausgefunden, dass dieser Markt wesentlich risikoreicher i...

  11. Beyond body mass index.

    OpenAIRE

    Prentice, AM; Jebb, SA

    2001-01-01

    Body mass index (BMI) is the cornerstone of the current classification system for obesity and its advantages are widely exploited across disciplines ranging from international surveillance to individual patient assessment. However, like all anthropometric measurements, it is only a surrogate measure of body fatness. Obesity is defined as an excess accumulation of body fat, and it is the amount of this excess fat that correlates with ill-health. We propose therefore that much greater attention...

  12. Refractive index based measurements

    DEFF Research Database (Denmark)

    SØrensen, Henrik SchiØtt Technical University of Denmark,

    In a method for performing a refractive index based measurement of a property of a fluid such as chemical composition or temperature, a chirp in the local spatial frequency of interference fringes of an interference pattern is reduced by mathematical manipulation of the recorded light intensity in the interference pattern or by the physical positioning and arrangement of a detector used for capturing the interference pattern.

  13. Perfectly Secure Index Coding

    OpenAIRE

    Mojahedian, Mohammad Mahdi; Gohari, Amin; Aref, Mohammad Reza

    2015-01-01

    In this paper, we investigate the index coding problem in the presence of an eavesdropper. Messages are to be sent from one transmitter to a number of legitimate receivers who have side information about the messages, and share a set of secret keys with the transmitter. We assume perfect secrecy, meaning that the eavesdropper should not be able to retrieve any information about the message set. This problem is a generalization of the Shannon's cipher system. We study the min...

  14. Indexing Cost Sensitive Prediction

    OpenAIRE

    Battle, Leilani; Benson, Edward; Parameswaran, Aditya; Wu, Eugene

    2014-01-01

    Predictive models are often used for real-time decision making. However, typical machine learning techniques ignore feature evaluation cost, and focus solely on the accuracy of the machine learning models obtained utilizing all the features available. We develop algorithms and indexes to support cost-sensitive prediction, i.e., making decisions using machine learning models taking feature evaluation cost into account. Given an item and a online computation cost (i.e., time) ...

  15. Indexical Hybrid Tense Logic

    DEFF Research Database (Denmark)

    Blackburn, Patrick Rowan; Jørgensen, Klaus Frovin

    2012-01-01

    In this paper we explore the logic of now, yesterday, today and tomorrow by combining the semantic approach to indexicality pioneered by Hans Kamp [9] and refined by David Kaplan [10] with hybrid tense logic. We first introduce a special now nominal (our @now corresponds to Kamp’s original now operator N) and prove completeness results for both logical and contextual validity. We then add propositional constants to handle yesterday, today and tomorrow; our system correctly treats sentences like ...

  16. Refractive index based measurements

    DEFF Research Database (Denmark)

    In a method for performing a refractive index based measurement of a property of a fluid such as chemical composition or temperature by observing an apparent angular shift in an interference fringe pattern produced by back or forward scattering interferometry, ambiguities in the measurement caused by the apparent shift being consistent with one of a number of numerical possibilities for the real shift which differ by 2n are resolved by combining measurements performed on the same sample using li...

  17. Influence of local air velocity from air conditioner evaluated by salivary and skin biomarkers

    Energy Technology Data Exchange (ETDEWEB)

    Yamaguchi, Masaki; Takahashi, Takayuki; Yoshino, Yuichiro; Sasaki, Makoto [Graduate School of Engineering, Iwate University, 4-3-5 Ueda, Morioka 020-8551 (Japan); Nishimiya, Hajime [Asahi Kasei Homes Corporation, R and D Laboratories, 2-1 Samejima, Fuji, Shizuoka 416-8501 (Japan)

    2010-11-15

    The purpose of this paper is to reveal both the psychosomatic and the physical effects of local air velocity from an air conditioner using biomarkers which can be collected noninvasively. Salivary {alpha}-amylase activity (SAA) and salivary cortisol were used as the indexes of psychosomatic effects. The total protein (TP) collected from stratum corneum was used as an index of the physical condition of dry skin. A continuous experiment over a 5 days period in summer was conducted using 8 healthy young male adults for 2-types of airflow conditioners, a whole ceiling-type air conditioner (without local air velocity) and a normal-type air conditioner (with local air velocity). The subjects felt cool, windy, dry and uncomfortable when under the normal-type air conditioner as determined in a subjective evaluation. The SAA under the normal-type air conditioner fluctuated more widely than with the whole ceiling-type air conditioner. The level of salivary cortisol decreased more in a day under the normal-type air conditioner than with the whole ceiling-type air conditioner. These results showed that reducing local air velocity may provide more healthy psychosomatic conditions over the long-term. Moreover, the TP of a drying-exposed skin area showed a significant change during this experiment whereas the TP of drying-protected area was relatively unchanged. It was indicated that one week's exposure to local air velocity conditions possibly influences the drying of facial skin. Thus, air movement at low velocity can be provides more comfortable conditions not only psychosomatically but also physically. (author)

  18. Index of Sequences

    CERN Document Server

    Gao, Weidong; Peng, Jiangtao; Plyley, Chris; Wang, Guoqing

    2009-01-01

    Let $Z_n$ denote the cyclic group of $n$ elements. For every $x\\in Z_n$, we denote by $|x|_n$ the smallest positive integer in the residual class $x$. Let $S=(a_1, ..., a_k)$ be a sequence of elements in $Z_n$. We say that $S$ has index $n$ if there is an integer $m$ co-prime to $n$ such that $\\sum_{i=1}^k|ma_i|_n=n$. In this paper, we prove that a sequence of $n$ elements in $Z_n$ with repetition at least $\\frac{n}{2}$ contains a subsequence with index $n$, and if $n=p$ is a prime the restriction of repetition can be relaxed to $\\frac{p-2}{10}$. On the other hand, for every $n=4k+2\\geq 22$, we give a sequence of length $n+\\lfloor \\frac{n}{4}\\rfloor-5$ and with repetition $\\frac{n}{2}-1$ which contains no subsequence with index $n$. This disproves a conjecture given twenty years ago by Lemke and Kleitman.

  19. 2001 Environmental Sustainability Index (ESI)

    Data.gov (United States)

    National Aeronautics and Space Administration — The 2001 Environmental Sustainability Index (ESI) utilizes a refined methodology based on the 2000 Pilot ESI effort, to construct an index covering 122 countries...

  20. VARIABILITY OF THE THERMAL CONTINENTALITY INDEX IN CENTRAL EUROPE

    Directory of Open Access Journals (Sweden)

    CIARANEK1 DOMINIKA

    2014-03-01

    Full Text Available The paper presents the spatial and temporal variability of thermal continentality in Central Europe. Gorczy?ski’s and Johansson-Ringleb’s formulae were used to derive the continentality index. The study also looked at the annual patterns of air temperature amplitude (A, a component of both of these formulae, and D; the difference between the average temperatures of autumn (Sep.-Nov. and spring (Mar.-May. Records of six weather stations representing the climate of Central Europe were included in the study covering the period 1775-2012 (Potsdam, Drezden, Prague, Vienna, Krakow, Debrecen. The highest continentality index was found in Debrecen and the lowest in Potsdam. The continentality index fluctuated with time with two pronounced dips at the turn of the 19th century and in the second half of the 20th century. The highest continentality index values were recorded during the 1930s and 1940s.

  1. Lies, Damn Lies, and Indexes.

    Science.gov (United States)

    Lance, Keith Curry; Cox, Marti A.

    2000-01-01

    Offers a methodological critique of Thomas Hennen's American Public Library Rating Index as well as a response by Hennen. Discusses statistics; indexes; correlations; variables; weighting; and how public libraries should be assessed, and Hennen defends his work and suggests it should be called a scorecard rather than an index. (LRW)

  2. EXFOR-INDEX. Index to EXFOR Neutron Data 1985

    International Nuclear Information System (INIS)

    This document summarizes the contents and documentation of the Index File to EXFOR Neutron Data (X4INDEX). This library is a sequential file of relevant index records extracted from an online Data Index data base at NDS. The data base is updated regularly, and each copy of the EXFOR Neutron Data Index is extracted directly from the current data base file. The second file of the EXFOR Neutron Data Index library is a copy of the relevant EXFOR dictionaries. This file is copied directly from the EXFOR Dictionary master file. The entire Index or selective retrievals from it can be obtained on magnetic tape free of charge from the IAEA Nuclear Data Section. (author)

  3. Research on Translation of Index ?-Net based on Index ?-Calculus

    Directory of Open Access Journals (Sweden)

    Hui Kang

    2013-03-01

    Full Text Available In terms of the definitions and features of index ?-calculus, a new kind of index ?-net is proposed in this paper, which can reflect the system actions of index ?-calculus system. This article presents definitions of Index ?-calculus places, transitions and arcs. Meanwhile, the conditions to activate a transition and the effects on the tokens of its successor place are given as well. We try not to disturb the nature of petri net while defining index ?-nets and expound the structural congruence relationship between them which verifies the semantic correctness of index ?-nets. Finally, a simplified model of index ?-nets is built, and a complete procedure about how the internal channel can be exposed to the external system is offered according to the model.

  4. Air quality

    International Nuclear Information System (INIS)

    The anthropic pollution sources are essentially industrial or bound to transport. A phenomenon of these last twenty years is the decreasing of the industrial pollution and the increasing of pollution coming from automobiles. Emissions of furans and dioxines coming from municipal wastes are measured. A special attention is mentioned for polycyclic aromatic hydrocarbons coming from incomplete combustions. A last aspect of air pollution is studied with the effect on man, ecosystems and materials, by modeling or direct measurements. (N.C.)

  5. 17th DOE nuclear air cleaning conference: proceedings. Volume 2

    International Nuclear Information System (INIS)

    Volume 2 contains papers presented at the following sessions: adsorption; noble gas treatment; personnel education and training; filtration and filter testing; measurement and instrumentation; air cleaning equipment response to accident related stress; containment venting air cleaning; and an open end session. Twenty-eight papers were indexed separately for inclusion in the Energy Data Base. Ten papers had been entered earlier

  6. 17th DOE nuclear air cleaning conference: proceedings. Volume 2

    Energy Technology Data Exchange (ETDEWEB)

    First, M.W. (ed.)

    1983-02-01

    Volume 2 contains papers presented at the following sessions: adsorption; noble gas treatment; personnel education and training; filtration and filter testing; measurement and instrumentation; air cleaning equipment response to accident related stress; containment venting air cleaning; and an open end session. Twenty-eight papers were indexed separately for inclusion in the Energy Data Base. Ten papers had been entered earlier.

  7. 30 CFR 7.89 - Test to determine the particulate index.

    Science.gov (United States)

    2010-07-01

    ...i-Subscript denoting an individual mode, i=1, . . . n PI—Particulate Index (cfm) (ii) When calculating ambient...10.71)) Where: Ha =humidity of the intake air, g water per kg dry air Ha =(6.220 * Ra * pa )/(pB...

  8. Negative refractive index metamaterials

    Directory of Open Access Journals (Sweden)

    Willie J. Padilla

    2006-07-01

    Full Text Available Engineered materials composed of designed inclusions can exhibit exotic and unique electromagnetic properties not inherent in the individual constituent components. These artificially structured composites, known as metamaterials, have the potential to fill critical voids in the electromagnetic spectrum where material response is limited and enable the construction of novel devices. Recently, metamaterials that display negative refractive index – a property not found in any known naturally occurring material – have drawn significant scientific interest, underscoring the remarkable potential of metamaterials to facilitate new developments in electromagnetism.

  9. Review of Cohesion in Indexing

    Directory of Open Access Journals (Sweden)

    Hasan Ashrafi Rizi

    2007-07-01

    Full Text Available Indexers often disagree on judging terms that best reflect the content of a document. Difference of opinion highlights one of the characteristics of indexing which is indexing cohesion. Also known as consistency, little study of the subject matter has been undertaken in the past few years. However, its importance has been recently acknowledged in effective information retrieval and expansion of access points to the document content. The present paper investigates cohesion in indexing. In addition of presenting the definitions offered by experts, it takes note of the factors influencing indexing cohesion. Methods for measuring cohesion are offered.

  10. Growth Index after Planck

    CERN Document Server

    Xu, Lixin

    2013-01-01

    To investigate the possible deviation from the standard $\\Lambda$CDM model and the Einstein's gravity theory in the dynamical perspectives, the growth index $\\gamma_L$ was proposed. Recently, thanks to the measurement of the cosmic growth rate via the redshift-space distortion, one can understand the evolution of density contrast through $f\\sigma_8(z)$, where $f(z)=d\\ln \\delta/d \\ln a$ is the growth rate of matter and $\\sigma_8(z)$ is the rms amplitude of the density contrast $\\delta$ at the comoving $8h^{-1}$ Mpc scale. In this paper, we use the red-shift space distortion data points to investigate the growth index on the bases of the Einstein's gravity theory and a modified gravity theory under the assumption $f=\\Omega_m(a)^{\\gamma_L}$. To fix the background evolution, the cosmic observational data points from the type Ia supernovae SNLS3, cosmic microwave background radiation from {\\it Planck} and baryon acoustic oscillation are used. Via the Markov Chain Monte Carlo method, the $\\gamma_L$ values were obta...

  11. Visceral Adiposity Index

    Science.gov (United States)

    Amato, Marco C.; Giordano, Carla; Galia, Massimo; Criscimanna, Angela; Vitabile, Salvatore; Midiri, Massimo; Galluzzo, Aldo

    2010-01-01

    OBJECTIVE To individuate a novel sex-specific index, based on waist circumference, BMI, triglycerides, and HDL cholesterol, indirectly expressing visceral fat function. RESEARCH DESIGN AND METHODS Visceral adiposity index (VAI) was first modeled on 315 nonobese healthy subjects. Using two multiple logistic regression models, VAI was retrospectively validated in 1,498 primary care patients in comparison to classical cardio- and cerebrovascular risk factors. RESULTS All components of metabolic syndrome increased significantly across VAI quintiles. VAI was independently associated with both cardiovascular (odd ratio [OR] 2.45; 95% CI 1.52–3.95; P < 0.001) and cerebrovascular (1.63; 1.06–2.50; P = 0.025) events. VAI also showed significant inverse correlation with insulin sensitivity during euglycemic-hyperinsulinemic clamp in a subgroup of patients (Rs = ?0.721; P < 0.001). By contrast, no correlations were found for waist circumference and BMI. CONCLUSIONS Our study suggests VAI is a valuable indicator of “visceral adipose function” and insulin sensitivity, and its increase is strongly associated with cardiometabolic risk. PMID:20067971

  12. A New Comparison of the "Current Index to Journals in Education" and the "Education Index": A Deep Analysis of Indexing.

    Science.gov (United States)

    Brown, M. Suzanne; Edwards, Jana S.; LaSee-Willemssen, Jeneen

    1999-01-01

    This article compares "Current Index to Journals in Education" (CIJE) with "Education Index" by article type and reveals pronounced differences in indexing practices. Implications for educational and interdisciplinary research, reference services, index selection, and library instruction are discussed. (Author)

  13. R9 Air Districts

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Region 9 Air Districts layer is a compilation of polygons representing the California Air Pollution Control and Air Quality Management Districts, Arizona Air...

  14. AirData

    Data.gov (United States)

    U.S. Environmental Protection Agency — The AirData site provides access to yearly summaries of United States air pollution data, taken from EPA's air pollution databases. AirData has information about...

  15. California Air Basins

    Data.gov (United States)

    California Department of Resources — Air ResourcesCalifornia Air Resources BoardThe following datasets are from the California Air Resources Board: * arb_california_airbasins - California Air BasinsThe...

  16. Dynamical measurement of refractive index distribution using digital holographic interferometry based on total internal reflection.

    Science.gov (United States)

    Zhang, Jiwei; Di, Jianglei; Li, Ying; Xi, Teli; Zhao, Jianlin

    2015-10-19

    We present a method for dynamically measuring the refractive index distribution in a large range based on the combination of digital holographic interferometry and total internal reflection. A series of holograms, carrying the index information of mixed liquids adhered on a total reflection prism surface, are recorded with CCD during the diffusion process. Phase shift differences of the reflected light are reconstructed exploiting the principle of double-exposure holographic interferometry. According to the relationship between the reflection phase shift difference and the liquid index, two dimensional index distributions can be directly figured out, assuming that the index of air near the prism surface is constant. The proposed method can also be applied to measure the index of solid media and monitor the index variation during some chemical reaction processes. PMID:26480394

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

    OpenAIRE

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

    2012-01-01

    Stagnant atmospheric conditions can lead to hazardous air quality by allowing ozone and particulate matter to accumulate and persist in the near-surface environment. By changing atmospheric circulation and precipitation patterns, global warming could alter the meteorological factors that regulate air stagnation frequency. We analyze the response of the National Climatic Data Center (NCDC) Air Stagnation Index (ASI) to anthropogenically enhanced radiative forcing using global climate model pro...

  18. Disparities in exposure to air pollution during pregnancy.

    OpenAIRE

    Woodruff, Tracey J.; Parker, Jennifer D; Kyle, Amy D.; Schoendorf, Kenneth C.

    2003-01-01

    Previous research shows poorer birth outcomes for racial and ethnic minorities and for persons with low socioeconomic status (SES). We evaluated whether mothers in groups at higher risk for poor birth outcomes live in areas of higher air pollution and whether higher exposure to air pollution contributes to poor birth outcomes. An index representing long-term exposure to criteria air pollutants was matched with birth certificate data at the county level for the United States in 1998-1999. We u...

  19. INTRA URBAN AIR TEMPERATURE DISTRIBUTIONS IN HISTORIC URBAN CENTER

    OpenAIRE

    Elmira Jamei; Dilshan Remaz Ossen

    2012-01-01

    The study investigates the urban heat island effect in Malaysian historic town Malacca through seven mobile traverses, as carried out on 10 December 2011. It aims to identify the intra-urban air temperature differences between heritage core zone, new development area and outskirts of the city. Air temperature variations were also analyzed across three different zones; namely the outskirts, the heritage site and the city center district. Heat index values were then calculated based on air temp...

  20. Generalizations of Wiener polarity index and terminal Wiener index

    CERN Document Server

    Ilic, Aleksandar

    2011-01-01

    In theoretical chemistry, distance-based molecular structure descriptors are used for modeling physical, pharmacologic, biological and other properties of chemical compounds. We introduce a generalized Wiener polarity index $W_k (G)$ as the number of unordered pairs of vertices $\\{u, v\\}$ of $G$ such that the shortest distance $d (u, v)$ between $u$ and $v$ is $k$. For $k = 3$, we get standard Wiener polarity index. Furthermore, we generalize the terminal Wiener index $TW_k (G)$ as the sum of distances between all pairs of vertices of degree $k$. For $k = 1$, we get standard terminal Wiener index. In this paper we describe a linear time algorithm for computing these indices for trees and partial cubes, and characterize extremal trees maximizing the generalized Wiener polarity index and generalized terminal Wiener index among all trees of given order $n$.

  1. Relationship between Phenological Stages and Cumulative Air Temperature in Spring Time at Namsan

    OpenAIRE

    Min, Byeong Mee; Dong Hoon Yi; Sang Jin Jeong

    2007-01-01

    To certify predictability for the times of phenological stages from cumulative air temperature inspringtime, the first times of budding, leafing, flower budding, flowering and deflowering for 14 woody plants weremonitored and air temperature was measured from 2005 to 2006 at Namsan. Year day index (YDI) andNuttonson's Index (Tn) were calculated from daily mean air temperature. Of the 14 woody species, mean coefficientof variation was 0.04 in Robinia pseudo-acacia and 0.09 in Alnus hirsuta. Ho...

  2. Acute management of vascular air embolism

    Directory of Open Access Journals (Sweden)

    Shaikh Nissar

    2009-01-01

    Full Text Available Vascular air embolism (VAE is known since early nineteenth century. It is the entrainment of air or gas from operative field or other communications into the venous or arterial vasculature. Exact incidence of VAE is difficult to estimate. High risk surgeries for VAE are sitting position and posterior fossa neurosurgeries, cesarean section, laparoscopic, orthopedic, surgeries invasive procedures, pulmonary overpressure syndrome, and decompression syndrome. Risk factors for VAE are operative site 5 cm? above the heart, creation of pressure gradient which will facilitate entry of air into the circulation, orogenital sex during pregnancy, rapid ascent in scuba (self contained underwater breathing apparatus divers and barotrauma or chest trauma. Large bolus of air can lead to right ventricular air lock and immediate fatality. In up to 35% patient, the foramen ovale is patent which can cause paradoxical arterial air embolism. VAE affects cardiovascular, pulmonary and central nervous system. High index of clinical suspicion is must to diagnose VAE. The transesophgeal echocardiography is the most sensitive device which will detect smallest amount of air in the circulation. Treatment of VAE is to prevent further entrainment of air, reduce the volume of air entrained and haemodynamic support. Mortality of VAE ranges from 48 to 80%. VAE can be prevented significantly by proper positioning during surgery, optimal hydration, avoiding use of nitrous oxide, meticulous care during insertion, removal of central venous catheter, proper guidance, and training of scuba divers.

  3. Inline fiber interference-based refractive-index sensor

    Science.gov (United States)

    Gong, Zhenfeng; Zhang, Xinpu; Liu, Yun; Liu, Zigeng; Yu, Qingxu; Peng, Wei

    2014-11-01

    We report two fiber multiple-mode interferometers formed in photonic crystal fiber (PCF). The interference between the core and the cladding modes of a PCF is utilized. We use two methods to form a coupling point, and the cladding modes are excited from the fundamental core mode. One method is blowing compressed gas into the air holes and discharging at the coupling point; the air holes will expand due to gas expansion in the discharge process. Similarly, the other is discharging at the coupling point after the air is exhausted from the air holes, and the holes will contract during the process. By making another coupling point at a different location along the fiber, the proposed PCF interferometers are implemented. Experimental results show that the sensitivities of the two devices can achieve 1.54 and 1.45 nm for a 0.01 refractive index change.

  4. 2012 Environmental Performance Index and Pilot Trend Environmental Performance Index

    Data.gov (United States)

    National Aeronautics and Space Administration — The 2012 Environmental Performance Index (EPI) ranks 132 countries on 22 performance indicators in the following 10 policy categories: environmental burden of...

  5. Beyond KERMA - neutron data for biomedical applications

    International Nuclear Information System (INIS)

    Presently, many new applications of fast neutrons are emerging or under development, like dose effects due to cosmic-ray neutrons for airplane crew, fast-neutron cancer therapy, studies of electronic failures induced by cosmic-ray neutrons, and accelerator-driven incineration of nuclear waste and energy production technologies. All these areas would benefit from improved neutron dosimetry. In this paper, the present rapid progress on measurements of double-differential neutron-induced nuclear reaction data are described. With such data at hand, the full response of, in principle, any system, including human tissue, can be calculated in detail. This could potentially revolutionise our understanding of biological effects in tissue due to fast neutrons. (author)

  6. Life quality index revisited

    DEFF Research Database (Denmark)

    Ditlevsen, Ove Dalager

    2004-01-01

    The derivation of the life quality index (LQI) is revisited for a revision. This revision takes into account the unpaid but necessary work time needed to stay alive in clean and healthy conditions to be fit for effective wealth producing work and to enjoyable free time. Dimension analysis consistency problems with the standard power function expression of the LQI are pointed out. It is emphasized that the combination coefficient in the convex differential combination between the relative differential of the gross domestic product per capita and the relative differential of the expected life at birth should not vary between countries. Finally the distributional assumptions are relaxed as compared to the assumptions made in an earlier work by the author. These assumptions concern the calculation of the life expectancy change due to the removal of an accident source. Moreover a simple public acceptance criterion is compared to the LQI criterion. (C) 2004 Elsevier Ltd. All rights reserved.

  7. Indexing contamination surveys

    International Nuclear Information System (INIS)

    The responsibility for safely managing the Tank Farms at Hanford belongs to Lockheed Martin Hanford Corporation which is part of the six company Project Hanford Management Team led by Fluor Daniel Hanford, Inc.. These Tank Farm Facilities contain numerous outdoor contamination areas which are surveyed at a periodicity consistent with the potential radiological conditions, occupancy, and risk of changes in radiological conditions. This document describes the survey documentation and data tracking method devised to track the results of contamination surveys this process is referred to as indexing. The indexing process takes a representative data set as an indicator for the contamination status of the facility. The data are further manipulated into a single value that can be tracked and trended using standard statistical methodology. To report meaningful data, the routine contamination surveys must be performed in a manner that allows the survey method and the data collection process to be recreated. Three key criteria are necessary to accomplish this goal: Accurate maps, consistent documentation, and consistent consolidation of data meeting these criteria provides data of sufficient quality to be tracked. Tracking of survey data is accomplished by converting the individual survey results into a weighted value, corrected for the actual number of survey points. This information can be compared over time using standard statistical analysis to identify trends. At the Tank Farms, the need to track and trend the facility's radiological status presents unique challenges. Many of these Tank Farm facilities date back to the second world war. The Tank Farm Facilities are exposed to weather extremes, plant and animal intrusion, as well as all of the normal challenges associated with handling radiological waste streams. Routine radiological surveys did not provide a radiological status adequate for continuing comparisons

  8. Aeronautical Engineering: 1983 cumulative index

    Science.gov (United States)

    1984-01-01

    This bibliography is a cumulative index to the abstracts contained in NASA SP-7037 (158) through NASA SP-7037 (169) of Aeronautical Engineering: A Continuing Bibliography. NASA SP-7037 and its supplements have been compiled through the cooperative efforts of the American Institute of Aeronautics and Astronautics (AIAA) and the National Aeronautics and Space Administration (NASA). This cumulative index includes subject, personal author, corporate source, contract, report number, and accession number indexes.

  9. Equiseparability on Terminal Wiener Index

    DEFF Research Database (Denmark)

    Deng, Xiaotie; Zhang, Jie

    2012-01-01

    The aim of this work is to explore the properties of the terminal Wiener index, which was recently proposed by Gutman et al. (2004) [3], and to show the fact that there exist pairs of trees and chemical trees which cannot be distinguished by using it. We give some general methods for constructing equiseparable pairs and compare the methods with the case for the Wiener index. More specifically, we show that the terminal Wiener index is degenerate to some extent.

  10. An Index of Loss Aversion

    OpenAIRE

    Köbberling, V.; Wakker, P.P.

    2005-01-01

    To a considerable extent, risk aversion as it is commonly observed is caused by loss aversion. Several indexes of loss aversion have been proposed in the literature. The one proposed in this paper leads to a clear decomposition of risk attitude into three distinct components: basic utility, probability weighting, and loss aversion. The index is independent of the unit of payment. The main theorem shows how the indexes of different decision makers can be compared through observ...

  11. Filter indexing for spectrophotometer system

    International Nuclear Information System (INIS)

    A spectrophotometer system has an optical system for transmitting a beam from a source at select wavelengths onto a detector. A plurality of filters are positioned in a tray. A stepper mechanism indexes the tray along a path. A microcomputer controls the stepper mechanism and the optical system. The wavelength is successively changed over a range, the tray is indexed to move a select filter into the beam at a predetermined wavelength and the changing is discontinued during indexing

  12. 2008 Environmental Performance Index (EPI)

    Data.gov (United States)

    National Aeronautics and Space Administration — The 2008 Environmental Performance Index (EPI) centers on two broad environmental protection objectives: (1) reducing environmental stresses on human health, and...

  13. 2002 Environmental Sustainability Index (ESI)

    Data.gov (United States)

    National Aeronautics and Space Administration — The 2002 Environmental Sustainability Index (ESI) measures overall progress toward environmental sustainability for 142 countries based on environmental systems,...

  14. 2010 Environmental Performance Index (EPI)

    Data.gov (United States)

    National Aeronautics and Space Administration — The 2010 Environmental Performance Index (EPI) ranks 163 countries on environmental performance based on twenty-five indicators grouped within ten core policy...

  15. Graded Index Microstructured Polymer Optical Fibers for Terahertz Applications

    CERN Document Server

    Ma, Tian; Wang, Lili; Skorobogatiy, Maksim

    2014-01-01

    Graded index microstructured polymer optical fiber incorporating a specially designed air-hole array featuring variable air-hole diameters and inter-hole separation is proposed, fabricated and characterized in view of the fiber potential applications in low-loss, low-dispersion terahertz guidance. The proposed fiber features simultaneously low chromatic and intermodal dispersions, as well as low loss in the terahertz spectral range. We then experimentally demonstrate that proposed fibers exhibit smaller pulse distortion, larger bandwidth and more reliable excitation when compared to the porous fibers of comparable geometry.

  16. Ion recombination in parallel-plate free-air ionization chambers for synchrotron radiation

    International Nuclear Information System (INIS)

    The saturation characteristics of two sizes of parallel-plate free-air ionization chambers were investigated for synchrotron radiation at bending-magnet, wiggler and undulator beamlines of SPring-8. The gaps of the electrodes were 4.2 and 85 mm. The monoenergetic photon energies ranged from 10 to 115.56 keV and the air kerma rates from 0.2 mGy s-1 to 150 kGy s-1. Ion recombination at the high dose rate was found to be smaller than that predicted by Boag's expression, which was based on volume recombination, and the difference increased with an applied electric field. In the high dose rate region, the reciprocal of the current was linear to the reciprocal of the electric field near saturation, which represented the occurrence of initial recombination and diffusion loss. At the low electric field and the low dose rate, the reciprocal of the current was linear to the reciprocal of the square of the electric field. The reduction of total ion recombination was attributed to the shift of the contribution from volume recombination to initial recombination and diffusion loss

  17. The Economic Value of Air Quality Forecasting

    Science.gov (United States)

    Anderson-Sumo, Tasha

    Both long-term and daily air quality forecasts provide an essential component to human health and impact costs. According the American Lung Association, the estimated current annual cost of air pollution related illness in the United States, adjusted for inflation (3% per year), is approximately $152 billion. Many of the risks such as hospital visits and morality are associated with poor air quality days (where the Air Quality Index is greater than 100). Groups such as sensitive groups become more susceptible to the resulting conditions and more accurate forecasts would help to take more appropriate precautions. This research focuses on evaluating the utility of air quality forecasting in terms of its potential impacts by building on air quality forecasting and economical metrics. Our analysis includes data collected during the summertime ozone seasons between 2010 and 2012 from air quality models for the Washington, DC/Baltimore, MD region. The metrics that are relevant to our analysis include: (1) The number of times that a high ozone or particulate matter (PM) episode is correctly forecasted, (2) the number of times that high ozone or PM episode is forecasted when it does not occur and (3) the number of times when the air quality forecast predicts a cleaner air episode when the air was observed to have high ozone or PM. Our collection of data included available air quality model forecasts of ozone and particulate matter data from the U.S. Environmental Protection Agency (EPA)'s AIRNOW as well as observational data of ozone and particulate matter from Clean Air Partners. We evaluated the performance of the air quality forecasts with that of the observational data and found that the forecast models perform well for the Baltimore/Washington region and the time interval observed. We estimate the potential amount for the Baltimore/Washington region accrues to a savings of up to 5,905 lives and 5.9 billion dollars per year. This total assumes perfect compliance with bad air quality warning and forecast air quality forecasts. There is a difficulty presented with evaluating the economic utility of the forecasts. All may not comply and even with a low compliance rate of 5% and 72% as the average probability of detection of poor air quality days by the air quality models, we estimate that the forecasting program saves 412 lives or 412 million dollars per year for the region. The totals we found are great or greater than other typical yearly meteorological hazard programs such as tornado or hurricane forecasting and it is clear that the economic value of air quality forecasting in the Baltimore/Washington region is vital.

  18. Applied Parallel Metadata Indexing

    Energy Technology Data Exchange (ETDEWEB)

    Jacobi, Michael R [Los Alamos National Laboratory

    2012-08-01

    The GPFS Archive is parallel archive is a parallel archive used by hundreds of users in the Turquoise collaboration network. It houses 4+ petabytes of data in more than 170 million files. Currently, users must navigate the file system to retrieve their data, requiring them to remember file paths and names. A better solution might allow users to tag data with meaningful labels and searach the archive using standard and user-defined metadata, while maintaining security. last summer, I developed the backend to a tool that adheres to these design goals. The backend works by importing GPFS metadata into a MongoDB cluster, which is then indexed on each attribute. This summer, the author implemented security and developed the user interfae for the search tool. To meet security requirements, each database table is associated with a single user, which only stores records that the user may read, and requires a set of credentials to access. The interface to the search tool is implemented using FUSE (Filesystem in USErspace). FUSE is an intermediate layer that intercepts file system calls and allows the developer to redefine how those calls behave. In the case of this tool, FUSE interfaces with MongoDB to issue queries and populate output. A FUSE implementation is desirable because it allows users to interact with the search tool using commands they are already familiar with. These security and interface additions are essential for a usable product.

  19. Ankle Brachial Index

    Energy Technology Data Exchange (ETDEWEB)

    Wikstroem, J.; Hansen, T.; Johansson, L.; Lind, L.; Ahlstroem, H. (Dept. of Radiology and Dept. of Medical Sciences, Uppsala Univ. Hospital, Uppsala (SE))

    2008-03-15

    Background: Whole-body magnetic resonance angiography (WBMRA) permits noninvasive vascular assessment, which can be utilized in epidemiological studies. Purpose: To assess the relation between a low ankle brachial index (ABI) and high-grade stenoses in the pelvic and leg arteries in the elderly. Material and Methods: WBMRA was performed in a population sample of 306 subjects aged 70 years. The arteries below the aortic bifurcation were graded after the most severe stenosis according to one of three grades: 0-49% stenosis, 50-99% stenosis, or occlusion. ABI was calculated for each side. Results: There were assessable WBMRA and ABI examinations in 268 (right side), 265 (left side), and 258 cases (both sides). At least one >=50% stenosis was found in 19% (right side), 23% (left side), and 28% (on at least one side) of the cases. The corresponding prevalences for ABI <0.9 were 4.5%, 4.2%, and 6.6%. An ABI cut-off value of 0.9 resulted in a sensitivity, specificity, and positive and negative predictive value of 20%, 99%, 83%, and 84% on the right side, and 15%, 99%, 82%, and 80% on the left side, respectively, for the presence of a >= 50% stenosis in the pelvic or leg arteries. Conclusion: An ABI <0.9 underestimates the prevalence of peripheral arterial occlusive disease in the general elderly population

  20. ATMOSPHERIC AIR QUALITY IN CALARASI TOWN

    Directory of Open Access Journals (Sweden)

    Cecilia NEAGU

    2013-01-01

    Full Text Available The present paper seeks to highlight the appearance of air pollution in Calarasi region on the basis of the annual reports of the environment in recent years and of the integrated air quality management for C?l?ra?i (data are presented about current and future emissions and concentrations of pollutants I tried to mark out the impurity of the atmospheric air from this area.Emission data interpretation was made on the basis of the inventory of emissions of pollutants in the air made for fixed and mobile sources in Calarasi town in recent years using the program Corinvent and Corinair emission factors, and imissions data were used to monitor the air quality monitoring network air quality. The index of the quality of the air showed the highest values in winter.There have been occasional instances of the limit provided by law for particulate matter PM10, Calarasi, or being the intense traffic, the topoclimate in summer periods with high temperatures and deficient pluviometric regime, but also because housing fuel winter warming solid. There major problems of environmental pollution of air quality in Calarasi town that falls within the limits imposed by the legislation in force. This is due especially to the fact that many industrial centres have been closed.

  1. Study of the sensitivity of gas sensing by use of index-guiding photonic crystal fibers.

    Science.gov (United States)

    Li, Shu-Guang; Liu, Si-Ying; Song, Zhao-Yuan; Han, Yin; Cheng, Tong-Lei; Zhou, Gui-Yao; Hou, Lan-Tian

    2007-08-01

    We demonstrate an absorption transmission spectrum of CH(4) in a 16.9 cm long index-guiding photonic crystal fiber (PCF) fabricated in our laboratory. One of the main factors to improve the sensitivity is to increase the fraction of power in PCF cladding air holes. We study the fraction of power in PCF cladding air holes as a function of the index-guiding PCF parameters. We found that a PCF with small spacing and a large air-filling ratio has a higher fraction of power in its cladding air holes. At the same time the mode area in this PCF is small and would generate strong nonlinear effects in the fiber. If we use a PCF in which the core is formed by missing seven air holes, it is immediately obvious that the PCF used as a sensor has higher sensitivity and a larger mode area. PMID:17676130

  2. VISCOSITY INDEX OF RAPESEED OIL

    Directory of Open Access Journals (Sweden)

    IOANA STANCIU

    2011-09-01

    Full Text Available In this paper were determined viscosity index of rapeseed oil using two methods. Viscosity index is calculated from the measured viscosity at 40 and 1000C using ASTM D 2270 and method graphically using ASTM D 341. The viscosity-temperature coefficient of rapeseed oil was calculated from the measured viscosity at 40 and 1000C.

  3. Maslov index for Hamiltonian systems

    Directory of Open Access Journals (Sweden)

    Alessandro Portaluri

    2008-01-01

    Full Text Available The aim of this article is to give an explicit formula for computing the Maslov index of the fundamental solutions of linear autonomous Hamiltonian systems in terms of the Conley-Zehnder index and the map time one flow.

  4. Indexing by Latent Semantic Analysis.

    Science.gov (United States)

    Deerwester, Scott; And Others

    1990-01-01

    Describes a new method for automatic indexing and retrieval called latent semantic indexing (LSI). Problems with matching query words with document words in term-based information retrieval systems are discussed, semantic structure is examined, singular value decomposition (SVD) is explained, and the mathematics underlying the SVD model is…

  5. Normalized-Difference Snow Index (NDSI)

    Science.gov (United States)

    Hall, Dorothy K.; Riggs, George A.

    2010-01-01

    The Normalized-Difference Snow Index (NDSI) has a long history. 'The use of ratioing visible (VIS) and near-infrared (NIR) or short-wave infrared (SWIR) channels to separate snow and clouds was documented in the literature beginning in the mid-1970s. A considerable amount of work on this subject was conducted at, and published by, the Air Force Geophysics Laboratory (AFGL). The objective of the AFGL work was to discriminate snow cover from cloud cover using an automated algorithm to improve global cloud analyses. Later, automated methods that relied on the VIS/NIR ratio were refined substantially using satellite data In this section we provide a brief history of the use of the NDSI for mapping snow cover.

  6. Metal-Air Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jiguang; Bruce, Peter G.; Zhang, Gregory

    2011-08-01

    Metal-air batteries have much higher specific energies than most currently available primary and rechargeable batteries. Recent advances in electrode materials and electrolytes, as well as new designs on metal-air batteries, have attracted intensive effort in recent years, especially in the development of lithium-air batteries. The general principle in metal-air batteries will be reviewed in this chapter. The materials, preparation methods, and performances of metal-air batteries will be discussed. Two main metal-air batteries, Zn-air and Li-air batteries will be discussed in detail. Other type of metal-air batteries will also be described.

  7. Measurement of low level ionization current in a new standard free air chamber derived from a 125I brachytherapy source

    International Nuclear Information System (INIS)

    In Japan, the number of I-125 brachytherapy case is rapidly increasing after they were approved as medical equipment by modification to relevant domestic laws in 2003. Presently, more than 100 hospitals provide the brachytherapy. It means that the demand for I-125 seed sources grow sharply. These leads that concern for quality assurance in practical clinic is raised up. It is our motivation to establish a primary standard for an I-125 brachytherapy source. In NMIJ, we have assembled a new free air chamber in order to measure reference air kerma rate (RAKR) which is defined in ICRU report 72. In order to gather enough ionization current in limited size of free air chamber, a technique which changes separation distance between voltage and collecting electrode have been developed in National Institute of Science and Technology. The two electrodes are made from thin aluminized film. They are perpendicular to beam line through an aperture from an I-125 brachytherapy source. In this technique, the secondary electron equilibrium state are maintained by canceling perturbation around these electrodes by subtracting obtained current at small volume from one at large volume. The collecting area between the two electrodes are surrounded by a cylindrical half voltage electrode. It prevent escaping of ionization charge from the collecting area. We applied this method to our chamber as a primary standard

  8. Air movement and perceived air quality

    DEFF Research Database (Denmark)

    Melikov, Arsen Krikor; Kaczmarczyk, J.

    2012-01-01

    The impact of air movement on perceived air quality (PAQ) and sick building syndrome (SBS) symptoms was studied. In total, 124 human subjects participated in four series of experiments performed in climate chambers at different combinations of room air temperature (20, 23, 26 and 28 °C), relative humidity (30, 40 and 70%) and pollution level (low and high). Most of the experiments were performed with and without facially applied airflow at elevated velocity. The importance of the use of recirculated room air and clean, cool and dry outdoor air was studied. The exposures ranged from 60. min to 235. min. Acceptability of PAQ and freshness of the air improved when air movement was applied. The elevated air movement diminished the negative impact of increased air temperature, relative humidity and pollution level on PAQ. The degree of improvement depended on the pollution level, the temperature and the humidity of the room air. At a low humidity level of 30% an increased velocity could compensate for the decreasein perceived air quality due to an elevated temperature ranging from 20 °C to 26 °C. In a room with 26 °C, increased air movement was also able to compensate for an increase in humidity from 30% to 60%, but not to 70%. The elevated velocity of recirculated polluted room air did not decrease the intensity of SBS symptoms, but movement of clean, cool and dry air did so. Energy-saving strategy of improving occupants' comfort in rooms by moving room air at high velocity and maintaining room temperature high at reduced supply of outdoor air or by a decrease of indoor air enthalpy should be cautiously implemented in buildings because the pollution level may still cause negative health effects. © 2011 Elsevier Ltd.

  9. Dow`s chemical exposure index guide

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, J.T.; Mundt, A. [Dow Chemical Co. Corp., Freeport, TX (United States)

    1995-07-01

    A number of events in the 1970`s and 1980`s impacted the course of process safety. Incidents such as Flixborough, Seveso, Three-Mile Island, and Bhopal are well known throughout industry and are recognized as examples of major disasters. Even though events leading up to these disasters were completely different they had one common element between them: a substance was released from a manufacturing unit, became airborne and presented a hazard of such magnitude as to place the safety of both employees and the surrounding public in jeopardy. As a result, industry became increasingly concerned regarding potential loss, in human and economic terms, as plants and equipment grew in size. The Flixborough incident raised the level of concern for process safety, particularly in terms of the hazards presented by fire and explosion. Seveso and Three-Mile Island emphasized the need to consider far-field exposure. The Bhopal incident created an urgent need to recognize and understand the expected downwind impact of potential releases of acutely toxic substances to the air. In order to meet this need, the Dow Chemical Company, a recognized leader in the area of safety and loss prevention, presented a Chemical Exposure Index in 1986. AIChE has recently published an updated version entitled Dow`s Chemical Exposure Index Guide. 7 refs., 5 figs.

  10. Indoor Air Quality

    Science.gov (United States)

    ... protect yourself and your family. Learn more Air Quality at Work Workers should breathe easy while on the job, but worksites with poor air quality put employees at risk. Healthy air is essential ...

  11. Air Travel and Diabetes

    Science.gov (United States)

    ... Size: A A A Listen Air Travel and Diabetes We continue to advocate for the rights travelers ... to people with diabetes. Explore: Air Travel and Diabetes Fact Sheet: Air Travel and Diabetes This fact ...

  12. Louisiana ESI: LG_INDEX (Large Index Polygons)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing the boundaries of all the hardcopy cartographic products produced as part of the Environmental Sensitivity Index...

  13. Louisiana ESI: SM_INDEX (Small Index Polygons)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing the boundaries of all the hardcopy cartographic products produced as part of the Environmental Sensitivity Index...

  14. Guam and the Northern Mariana Islands ESI: INDEX (Index Polygons)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing the boundaries of all hardcopy cartographic products produced as part of the Environmental Sensitivity Index...

  15. Bristol Bay, Alaska Subarea ESI: INDEX (Index Polygons)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing the boundaries of all the hardcopy cartographic products produced as part of the Environmental Sensitivity Index...

  16. Impact coverage of the success-index

    OpenAIRE

    Egghe, Leo

    2014-01-01

    We show mathematically that the success-index can be any of the following impact indices, dependent on the value of the threshold used in the definition of the success-index: Hirsch-index (h-index), g-index, generalized Wu- and Kosmulski-indices, the average.

  17. Effect of Preventive Maintenance on Performance of Air Heater in a Power Plant

    International Nuclear Information System (INIS)

    Air heater used in power plant helps increase the thermal efficiency of the boiler by recovering the heat from the boiler flue gas and thus preventing the loss of useful heat. This study investigates the effect of preventive maintenance on the performance of the air heater in a power plant. Performance indexes for the air heater are calculated to observe the changes in the performance and operation status of the air heater before and after preventive maintenance. The major performance indexes considered are temperature efficiency of the flue gas side, air leakage rate, heat recovery rate, heat transmission rate, and heat capacity ratio. The performance of the air heater is evaluated before and after preventive maintenance; our results show that all the above mentioned performance indexes are improved after the maintenance

  18. Air Quality System (AQS)

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Air Quality System (AQS) database contains measurements of air pollutant concentrations from throughout the United States and its territories. The measurements...

  19. Estimation of rice situation index in Japan using remotely sensed and meteorological data

    International Nuclear Information System (INIS)

    This research aims to develop a remote sensing method for monitoring rice production in Japan. A photosynthesis-based crop production index CPI for rice is proposed that takes into consideration the solar radiation, the effective air temperature, and normalized vegetation index NDVI as a factor representing vegetation biomass. The CPI index incorporates temperature influences such as the effect of temperature on photosynthesis by grain plant leaves, low-temperature effects of sterility, cool summer damage due to delayed growth, and high-temperature injury. These latter factors are significant at around the heading period of rice. The CPI index for rice was modeled at ten monitoring sites in the Kanto, Tohoku, and Hokkaido districts, which occasionally tend to suffer poor harvests as a result of low temperatures. The photosynthesis-based crop production index CPI proposed here can predict the crop situation index of rice by using NDVI, solar radiation at meteorological observatories and air temperature at AMeDAS sites. The method is based on routine observation data, allowing automated monitoring of rice situation index at arbitrary sites in Japan. However, it is possible to further refine the estimation formula for the rice situation index for early monitoring

  20. On the anodic aluminium oxide refractive index of nanoporous templates

    Science.gov (United States)

    Hierro-Rodriguez, A.; Rocha-Rodrigues, P.; Valdés-Bango, F.; Alameda, J. M.; Jorge, P. A. S.; Santos, J. L.; Araujo, J. P.; Teixeira, J. M.; Guerreiro, A.

    2015-11-01

    In the present study, we have determined the intrinsic refractive index of anodic aluminium oxide, which is originated by the formation of nanoporous alumina templates. Different templates have been fabricated by the conventional two-step anodization procedure in oxalic acid. Their porosities were modified by chemical wet etching allowing the tuning of their effective refractive indexes (air-filled nanopores??+??anodic aluminium oxide). By standard spectroscopic light transmission measurements, the effective refractive index for each different template was extracted in the VIS-NIR region. The determination of the intrinsic anodic aluminium oxide refractive index was performed by using the Maxwell-Garnett homogenization theory. The results are coincident for all the fabricated samples. The obtained refractive index (~1.55) is quite lower (~22%) than the commonly used Al2O3 handbook value (~1.75), showing that the amorphous nature of the anodic oxide structure strongly conditions its optical properties. This difference is critical for the correct design and modeling of optical plasmonic metamaterials based on anodic aluminium oxide nanoporous templates.

  1. ? dependence of the Witten index

    International Nuclear Information System (INIS)

    The ?-dependence of the regularized Witten index is commented in supersymmetric quantum mechanics focusing on the problem of periodic boundary conditions and the normalization of the corresponding eigenstates. (Author)

  2. Energy Index For Aircraft Maneuvers

    Science.gov (United States)

    Chidester, Thomas R. (Inventor); Lynch, Robert E. (Inventor); Lawrence, Robert E. (Inventor); Amidan, Brett G. (Inventor); Ferryman, Thomas A. (Inventor); Drew, Douglas A. (Inventor); Ainsworth, Robert J. (Inventor); Prothero, Gary L. (Inventor); Romanowski, Tomothy P. (Inventor); Bloch, Laurent (Inventor)

    2006-01-01

    Method and system for analyzing, separately or in combination, kinetic energy and potential energy and/or their time derivatives, measured or estimated or computed, for an aircraft in approach phase or in takeoff phase, to determine if the aircraft is or will be put in an anomalous configuration in order to join a stable approach path or takeoff path. A 3 reference value of kinetic energy andor potential energy (or time derivatives thereof) is provided, and a comparison index .for the estimated energy and reference energy is computed and compared with a normal range of index values for a corresponding aircraft maneuver. If the computed energy index lies outside the normal index range, this phase of the aircraft is identified as anomalous, non-normal or potentially unstable.

  3. French Basic Course. Grammatical Index.

    Science.gov (United States)

    Defense Language Inst., Monterey, CA.

    This index is intended for use with Volumes 1 through 8 of the French Basic Course. It facilitates the finding of grammatical references in those volumes. The items are cross-referenced and arranged in alphabetical order. (Author/AMH)

  4. Introduction to indexing and abstracting

    CERN Document Server

    Cleveland, Ana

    2013-01-01

    Successful information access in the digital information age requires robust systems of indexing and abstracting. This book provides a complete introduction to the subject that covers the many recent changes in the field.

  5. Region 9 - Social Vulnerability Index

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Social Vulnerability Index is derived from the 2000 US Census data. The fields included are percent minority, median household income, age (under 18 and over...

  6. Energetic consumption levels and human development indexes

    International Nuclear Information System (INIS)

    The article overviews the energetic consumption levels and human development indexes. The human development indexes are described based on the United Nations Development Programme. A comparison between the energetic consumption levels and human development indexes is also presented

  7. Water analysis. Beta radioactivity indexes

    International Nuclear Information System (INIS)

    Beta radiation emission of an aqueous sample is compared to ? radiation emission of a calibrated source (90Sr + 90Y in radioactive equilibrium). Two conventional values, called beta radioactivity index of the soluble fraction and beta radioactivity index of the insoluble fraction, are determined. Particles of low energy, volatile products, absorption and retrodiffusion are not taken into account. The method is applicable to rainwater, surface waters and ground water, containing in solution from 0 to 500 mg of matter

  8. The 'Antidirector Rights Index' Revisited

    OpenAIRE

    Spamann, Holger

    2010-01-01

    The “antidirector rights index” has been used as a measure of shareholder protection in over a hundred articles since it was introduced by La Porta et al. (“Law and Finance.” 1998, Journal of Political Economy 106:1113–55). A thorough reexamination of the legal data, however, leads to corrections for thirty-three of the forty-six countries analyzed. The correlation between corrected and original values is only 0.53. Consequently, many empirical results established using the original index may...

  9. Movie indexing via event detection

    OpenAIRE

    Lehane, Bart; O'Connor, Noel E

    2006-01-01

    The past number of years has seen a large increase in the number of movies, and therefore movie databases, created. As movies are typically quite long, locating relevant clips in these databases is quite difficult unless a well defined index is in place. As movies are creatively made, creating automatic indexing algorithms is a challenging task. However, there are a number of underlying film grammar principles that are universally followed. By detecting and examining the use of these principl...

  10. PC index and magnetic substorms

    Science.gov (United States)

    Troshichev, Oleg; Janzhura, Alexander; Sormakov, Dmitry; Podorozhkina, Nataly

    PC index is regarded as a proxy of the solar wind energy that entered into the magnetosphere as distinct from the AL and Dst indices, which are regarded as characteristics of the energy that realize in the magnetosphere in form of substorm and magnetic storms. This conclusion is based on results of analysis of relationships between the polar cap magnetic activity (PC-index) and parameters of the solar wind, on the one hand, relationships between changes of PC and development of magnetospheric substorms (AL-index) and magnetic storms (Dst-index), on the other hand. This paper describes in detail the following main results which demonstrate a strong connection between the behavior of PC and development of magnetic disturbances in the auroral zone: (1) magnetic substorms are preceded by the ?? index growth (isolated and extended substorms) or long period of stationary PC (postponed substorms), (2) the substorm sudden onsets are definitely related to such PC signatures as leap and reverse, which are indicative of sharp increase of the PC growth rate, (3) substorms generally start to develop when the PC index exceeds the threshold level ~ 1.5±0.5 mV/m, irrespective of the substorm growth phase duration and type of substorm, (4) linear dependency of AL values on PC is typical of all substorm events irrespective of type and intensity of substorm.

  11. Trajectory Indexing Using Movement Constraints

    DEFF Research Database (Denmark)

    Pfoser, D.; Jensen, Christian SØndergaard

    2005-01-01

    With the proliferation of mobile computing, the ability to index efficiently the movements of mobile objects becomes important. Objects are typically seen as moving in two-dimensional (x,y) space, which means that their movements across time may be embedded in the three-dimensional (x,y,t) space. Further, the movements are typically represented as trajectories, sequences of connected line segments. In certain cases, movement is restricted; specifically, in this paper, we aim at exploiting that movements occur in transportation networks to reduce the dimensionality of the data. Briefly, the idea is to reduce movements to occur in one spatial dimension. As a consequence, the movement occurs in two-dimensional (x,t) space. The advantages of considering such lower-dimensional trajectories are that the overall size of the data is reduced and that lower-dimensional data is to be indexed. Since off-the-shelf database management systems typically do not offer higher-dimensional indexing, this reduction in dimensionality allows us to use existing DBMSes to store and index trajectories. Moreover, we argue that, given the right circumstances, indexing these dimensionality-reduced trajectories can be more efficient than using a three-dimensional index. A decisive factor here is the fractal dimension of the network.the lower, the more efficient is the proposed approach. This hypothesis is verified by an experimental study that incorporates trajectories stemming from real and synthetic road networks. Udgivelsesdato: JUN

  12. Indexes to Nuclear Regulatory Commission Issuances

    International Nuclear Information System (INIS)

    Digests and indexes for issuances of the Commission (CLI), the Atomic Safety and licensing Board Panel (LBP), the Administrative Law Judges (ALJ) the Directors' Decisions (DD), and the Decisions on Petitions for Rulemaking (DPRM) are presented in this document. These digests and indexes are intended to serve as a guide to the issuances. Information elements are displayed in one or more of five separate formats arranged as follows: Case Name Index; Headers and Digests; Legal Citations Index; Subject Index; and Facility Index

  13. Indexing from thesauri to the semantic web

    CERN Document Server

    de Keyser, Piet

    2012-01-01

    Indexing consists of both novel and more traditional techniques. Cutting-edge indexing techniques, such as automatic indexing, ontologies, and topic maps, were developed independently of older techniques such as thesauri, but it is now recognized that these older methods also hold expertise. Indexing describes various traditional and novel indexing techniques, giving information professionals and students of library and information sciences a broad and comprehensible introduction to indexing. This title consists of twelve chapters: an Introduction to subject readings and theasauri; Automatic i

  14. A STUDY ON VARIATION IN BIOCHEMICAL ASPECTS OF DIFFERENT TREE SPECIES WITH TOLERANCE AND PERFORMANCE INDEX

    OpenAIRE

    MEHA BORA; NAMITA JOSHI

    2014-01-01

    The present study was undertaken to evaluate the variation between biochemical characteristics and air pollution tolerance index (APTI) of 6 different plant species. The results of the present study indicate that APTI was significantly correlated with total chlorophyll, ascorbic acid, leaf pH for all species and are the most significant and determining factors on which the tolerance depends. The order of tolerance index of plant species is as follows Saraca indica (13.71), Azadira...

  15. 7 CFR 5.1 - Parity index and index of prices received by farmers.

    Science.gov (United States)

    2010-01-01

    ...Parity index and index of prices received by farmers. 5.1 Section 5.1 Agriculture...Parity index and index of prices received by farmers. (a) The parity index and...shall be the index of prices paid by farmers, interest, taxes, and farm wage...

  16. Patient dose measurement and dose reduction in chest radiography

    OpenAIRE

    Milatovi? Aleksandra A.; Spasi?-Joki? Vesna M.; Jovanovi? Slobodan I.

    2014-01-01

    Investigations presented in this paper represent the first estimation of patient doses in chest radiography in Montenegro. In the initial stage of our study, we measured the entrance surface air kerma and kerma area product for chest radiography in five major health institutions in the country. A total of 214 patients were observed. We reported the mean value, minimum and third quartile values, as well as maximum values of surface air kerma and kerma area p...

  17. Venture Capital Industry Index Portfolio Analysis

    Directory of Open Access Journals (Sweden)

    Dagang Yang

    2013-05-01

    Full Text Available This paper using index analysis method, knowledge of venture capital as well as index funds investment ideas, successively set up the Markowitz model and the single index model of index investing. Markowitz model for the calculation of the risk of workload is too big and single-index model although accuracy is slightly lower, but can certainly be very well used in practice. Therefore, We use index invest to invest in Shanghai 10 index securities with the single-index model , and apply lingo software to figure out the venture capital portfolio which have different yields.

  18. Air filtration and indoor air quality

    DEFF Research Database (Denmark)

    Bekö, Gabriel

    2006-01-01

    Demands for better indoor air quality are increasing, since we spend most of our time indoors and we are more and more aware of indoor air pollution. Field studies in different parts of the world have documented that high percentage of occupants in many offices and buildings find the indoor air quality (IAQ) unacceptable and suffer from Sick Building Syndrome (SBS) symptoms (e.g. respiratory, headache, fatigue, etc.). In addition, prevalence of asthma and other respiratory and allergic diseases have increased during the past decades. The effect is most likely related to the environment. Without decent ventilation and air cleaning/air filtration, high indoor air quality cannot be accomplished. The need for effective air filtration has increased with increasing evidence on the hazardous effects of fine particles. Moreover, the air contains gaseous pollutants, removal of which requires various air cleaning techniques. Supply air filter is one of the key components in the ventilation system. Studies have shown that used ventilation filters themselves can be a significant source of indoor air pollution with consequent impact on perceived air quality, sick building syndrome symptoms and performance. Usually, increasing the ventilation rate improves the air quality, however in the case of used ventilation filters the benefits from increasing the airflow are smaller than usual. Moreover, the ever-increasing pressure drop of bag filters tends to raise energy costs of ventilation systems. These contradictions should motivate manufacturers and researchers to develop new efficient filtration techniques and/or improve the existing ones. Development of low polluting filtration techniques, which are at the same time easy and inexpensive to maintain is the way forward in the future.

  19. Assessment of air quality around a coal mine using ORAQI indices

    Energy Technology Data Exchange (ETDEWEB)

    Chandra, S.M.; Rao, G.A. [Regional Engineering College, Warangal (India). Dept. of Civil Engineering

    2004-07-01

    Air-quality deterioration due to large-scale coal mining, transportation, and small-scale utilization activities in the Manuguru coal belt area of Andhra Pradesh has become a matter of concern. Two opencast mines, three underground mines and a coal-handling plant have environmental impacts on the ambient atmosphere. Hence, it is necessary to assess the air quality of the study area using air quality data. Overall, air quality is obtained from the ORAQI (Oak Ridge Air Quality index). Results of the study indicate that the overall air quality represented by the indicies is relatively inferior in summer and superior in the post-monsoon season. 7 refs., 1 tab.

  20. Improving the Performance of Temperature Index Snowmelt Model of SWAT by Using MODIS Land Surface Temperature Data

    OpenAIRE

    Yan Yang; Takeo Onishi; Ken Hiramatsu

    2014-01-01

    Simulation results of the widely used temperature index snowmelt model are greatly influenced by input air temperature data. Spatially sparse air temperature data remain the main factor inducing uncertainties and errors in that model, which limits its applications. Thus, to solve this problem, we created new air temperature data using linear regression relationships that can be formulated based on MODIS land surface temperature data. The Soil Water Assessment Tool model, which includes an imp...

  1. State of the air report 2007 in British Columbia

    International Nuclear Information System (INIS)

    This report provided details of local and regional air quality measurements and provided updates on information related to climate change in British Columbia (BC). A description of the new air quality health index pilot for users in BC was provided. The report was created by the BC Lung Association and various municipal, regional, provincial, and federal air quality protection agencies in order to develop a better understanding of issues that affect air quality. The report provided details of common air pollutants in BC, as well as details of pollution levels from various monitoring sites in the province. Ground-level ozone measurements were presented, as well as ambient levels of nitrogen dioxide (NO2) and sulphur dioxide (SO2). Details of the Quesnel airshed management plan were outlined. Updates on locomotive emissions and woodburning stove emissions in the province were provided. New methods of disposing agricultural plastics were discussed. Recent air pollution bylaws, regulations, and program management plans were also outlined. 17 figs

  2. Air movement and perceived air quality

    DEFF Research Database (Denmark)

    Melikov, Arsen Krikor; Kaczmarczyk, J.

    2012-01-01

    The impact of air movement on perceived air quality (PAQ) and sick building syndrome (SBS) symptoms was studied. In total, 124 human subjects participated in four series of experiments performed in climate chambers at different combinations of room air temperature (20, 23, 26 and 28 °C), relative humidity (30, 40 and 70%) and pollution level (low and high). Most of the experiments were performed with and without facially applied airflow at elevated velocity. The importance of the use of recircul...

  3. Air filtration and indoor air quality

    DEFF Research Database (Denmark)

    Bekö, Gabriel

    2006-01-01

    Demands for better indoor air quality are increasing, since we spend most of our time indoors and we are more and more aware of indoor air pollution. Field studies in different parts of the world have documented that high percentage of occupants in many offices and buildings find the indoor air quality (IAQ) unacceptable and suffer from Sick Building Syndrome (SBS) symptoms (e.g. respiratory, headache, fatigue, etc.). In addition, prevalence of asthma and other respiratory and allergic diseases ...

  4. Air movement and perceived air quality

    OpenAIRE

    Melikov, Arsen Krikor; J. Kaczmarczyk

    2011-01-01

    The impact of air movement on perceived air quality (PAQ) and sick building syndrome (SBS) symptoms was studied. In total, 124 human subjects participated in four series of experiments performed in climate chambers at different combinations of room air temperature (20, 23, 26 and 28 °C), relative humidity (30, 40 and 70%) and pollution level (low and high). Most of the experiments were performed with and without facially applied airflow at elevated velocity. The importance of the use of recir...

  5. Understanding air release through air valves

    OpenAIRE

    MARIA DEL MAR CARLOS ALBEROLA; Arregui de la Cruz, Francisco; Cabrera Marcet, Enrique; Palau C.V.

    2011-01-01

    Water transients with entrapped air can originate large pressure peaks that can severely damage distribution networks. Entrapped air can have a damping or amplifying effect on these undesirable pressure peaks. Unfortunately, the complexity of the phenomenon too often makes it difficult to obtain a fully reliable prediction about when air pockets will mitigate or accentuate water transients. Furthermore, the value of some of the parameters involved in the conventional numerical models cannot b...

  6. Terahertz Wave Guiding by Femtosecond Laser Filament in Air

    OpenAIRE

    Zhao, Jiayu; Zhang, Yizhu; Wang, Zhi; Chu, Wei; ZENG, BIN; Cheng, Ya; Xu, Zhizhan; Liu, Weiwei

    2013-01-01

    Femtosecond laser filament generates strong terahertz (THz) pulse in air. In this paper, THz pulse waveform generated by femtosecond laser filament has been experimentally investigated as a function of the length of the filament. Superluminal propagation of THz pulse has been uncovered, indicating that the filament creates a THz waveguide in air. Numerical simulation has confirmed that the waveguide is formed because of the radially non-uniform refractive index distribution ...

  7. DIDA: Distributed Indexing Dispatched Alignment.

    Science.gov (United States)

    Mohamadi, Hamid; Vandervalk, Benjamin P; Raymond, Anthony; Jackman, Shaun D; Chu, Justin; Breshears, Clay P; Birol, Inanc

    2015-01-01

    One essential application in bioinformatics that is affected by the high-throughput sequencing data deluge is the sequence alignment problem, where nucleotide or amino acid sequences are queried against targets to find regions of close similarity. When queries are too many and/or targets are too large, the alignment process becomes computationally challenging. This is usually addressed by preprocessing techniques, where the queries and/or targets are indexed for easy access while searching for matches. When the target is static, such as in an established reference genome, the cost of indexing is amortized by reusing the generated index. However, when the targets are non-static, such as contigs in the intermediate steps of a de novo assembly process, a new index must be computed for each run. To address such scalability problems, we present DIDA, a novel framework that distributes the indexing and alignment tasks into smaller subtasks over a cluster of compute nodes. It provides a workflow beyond the common practice of embarrassingly parallel implementations. DIDA is a cost-effective, scalable and modular framework for the sequence alignment problem in terms of memory usage and runtime. It can be employed in large-scale alignments to draft genomes and intermediate stages of de novo assembly runs. The DIDA source code, sample files and user manual are available through http://www.bcgsc.ca/platform/bioinfo/software/dida. The software is released under the British Columbia Cancer Agency License (BCCA), and is free for academic use. PMID:25923767

  8. Review of air pollution and health impacts in Malaysia

    International Nuclear Information System (INIS)

    In the early days of abundant resources and minimal development pressures, little attention was paid to growing environmental concerns in Malaysia. The haze episodes in Southeast Asia in 1983, 1984, 1991, 1994, and 1997 imposed threats to the environmental management of Malaysia and increased awareness of the environment. As a consequence, the government established Malaysian Air Quality Guidelines, the Air Pollution Index, and the Haze Action Plan to improve air quality. Air quality monitoring is part of the initial strategy in the pollution prevention program in Malaysia. Review of air pollution in Malaysia is based on the reports of the air quality monitoring in several large cities in Malaysia, which cover air pollutants such as Carbon monoxide (CO), Sulphur Dioxide (SO2), Nitrogen Dioxide (NO2), Ozone (O3), and Suspended Particulate Matter (SPM). The results of the monitoring indicate that Suspended Particulate Matter (SPM) and Nitrogen Dioxide (NO2) are the predominant pollutants. Other pollutants such as CO, Ox, SO2, and Pb are also observed in several big cities in Malaysia. The air pollution comes mainly from land transportation, industrial emissions, and open burning sources. Among them, land transportation contributes the most to air pollution. This paper reviews the results of the ambient air quality monitoring and studies related to air pollution and health impacts

  9. Review of air pollution and health impacts in Malaysia.

    Science.gov (United States)

    Afroz, Rafia; Hassan, Mohd Nasir; Ibrahim, Noor Akma

    2003-06-01

    In the early days of abundant resources and minimal development pressures, little attention was paid to growing environmental concerns in Malaysia. The haze episodes in Southeast Asia in 1983, 1984, 1991, 1994, and 1997 imposed threats to the environmental management of Malaysia and increased awareness of the environment. As a consequence, the government established Malaysian Air Quality Guidelines, the Air Pollution Index, and the Haze Action Plan to improve air quality. Air quality monitoring is part of the initial strategy in the pollution prevention program in Malaysia. Review of air pollution in Malaysia is based on the reports of the air quality monitoring in several large cities in Malaysia, which cover air pollutants such as Carbon monoxide (CO), Sulphur Dioxide (SO2), Nitrogen Dioxide (NO2), Ozone (O3), and Suspended Particulate Matter (SPM). The results of the monitoring indicate that Suspended Particulate Matter (SPM) and Nitrogen Dioxide (NO2) are the predominant pollutants. Other pollutants such as CO, O(x), SO2, and Pb are also observed in several big cities in Malaysia. The air pollution comes mainly from land transportation, industrial emissions, and open burning sources. Among them, land transportation contributes the most to air pollution. This paper reviews the results of the ambient air quality monitoring and studies related to air pollution and health impacts. PMID:12854685

  10. EXPERIMENTAL INVESTIGATION ON ROOM AIR FLOW PATTERN & THERMAL COMFORT QUANTIFICATION

    Directory of Open Access Journals (Sweden)

    Yogesh S. Fulpagare

    2013-08-01

    Full Text Available It is well known that indoor environment is an important factor not only for occupants’ comfort as a whole, but also for their health and productivity. Air distribution achieves the acceptable levels of temperature, humidity, cleanliness and air motion in the occupied zone of conditioned area. All this is done in such a manner that the occupant does not experience any draft. Airflow and transport phenomena play an important role in air quality, thermal comfort and energy consumption in buildings. Air movement is one of the six main variables determining human thermal comfort. The present work focuses on the room air flow pattern in terms of temperature and velocity along with thermal comfort quantification by varying clothing index. Room air flow pattern in the two test rooms, University conference hall and RAC (Refrigeration and Air Conditioning Lab are studied under four conditions; natural, only fan, only AC, fan with AC. Effect of air conditioner position on the room air flow pattern is also studied. Thermal comfort is quantified using standard ASHRAE sensational equation based on the feelings of the four B. Tech students at various clothing index and exposure period. The contour of the flow patterns are plotted using ORIGIN 6.1 software.It is advisable to operate the ceiling fan at moderate speed with air conditioner to get the uniform flow pattern with respect to temperature and velocity which leads to saving in energy. Air flow pattern depends on the location of the air conditioner. Thermal comfort depends on the clothing resistance and activity level.

  11. Sparse single-index model

    CERN Document Server

    Alquier, Pierre

    2011-01-01

    The single-index model is known to offer a flexible way to model a variety of high-dimensional real-world phenomena. However, despite its relative implicity, this dimension reduction scheme is faced with severe complications as soon as the underlying dimension becomes larger than the number of observations ("p larger than n" paradigm). To circumvent this difficulty, we consider the single-index model estimation problem from a sparsity perspective using a PAC-Bayesian approach. On the theoretical side, we offer a sharp oracle inequality, which is more powerful than the best known oracle inequality for other common procedures of single-index recovery. The proposed method is implemented by means of the reversible jump Markov chain Monte Carlo technique and its performance is compared with that of standard procedures.

  12. Socializing the h-index

    CERN Document Server

    Cormode, Graham; Muthukrishnan, S; Thompson, Brian

    2012-01-01

    A variety of bibliometric measures have been proposed to quantify the impact of researchers and their work. The h-index is a notable and widely-used example which aims to improve over simple metrics such as raw counts of papers or citations. However, a limitation of this measure is that it considers authors in isolation and does not account for contributions through a collaborative team. To address this, we propose a natural variant that we dub the Social h-index. The idea is to redistribute the h-index score to reflect an individual's impact on the research community. In addition to describing this new measure, we provide examples, discuss its properties, and contrast with other measures.

  13. Connective eccentric index of some graph operations

    OpenAIRE

    Nilanjan De; Pal, Anita; Nayeem, Sk. Md. Abu

    2014-01-01

    The connective eccentric index of a graph is a topological index involving degrees and eccentricities of vertices of the graph. In this paper, we have studied the connective eccentric index for double graph and double cover. Also we give the connective eccentric index for some graph operations such as joins, symmetric difference, disjunction and splice of graphs.

  14. Event Index - a LHCb Event Search System

    CERN Document Server

    Ustyuzhanin, Andrey; Kazeev, Nikita; Redkin, Artem

    2015-01-01

    LHC experiments generate up to $10^{12}$ events per year. This paper describes Event Index - an event search system. Event Index's primary function is quickly selecting subsets of events from a combination of conditions, such as the estimated decay channel or stripping lines output. Event Index is essentially Apache Lucene optimized for read-only indexes distributed over independent shards on independent nodes.

  15. Index Simulation Feasibility and Automatic Document Classification.

    Science.gov (United States)

    Fried, J.B.; And Others

    The objectives of this research were to investigage (1) the feasibility of an index simulator, and (2) the use of a sequential analysis model for the automatic classification of documents. Index simulation was studied in general for various types of indexes, and in depth for the simulation of an inverted coordinate index to a document collection…

  16. A Modified Consumer Price Index

    OpenAIRE

    Xiangrong Li; Gonglin Yuan

    2010-01-01

    It is well known that the Consumer Price Index (CPI), as a Laspeyrestype index, attempts to measure the average change in the prices paid by urban consumers for a fixed market of goods and services, and new samples for most item categories are routinely introduced over time to keep the CPI sample representative of consumer spending patterns. The CPI normally overstates the true rate of increase of the cost of living. In this paper, our main objective is to propose a new measurement in the CPI...

  17. FM-index for dummies

    OpenAIRE

    Grabowski, Szymon; Raniszewski, Marcin; Deorowicz, Sebastian

    2015-01-01

    The FM-index is a celebrated compressed data structure for full-text pattern searching. After the first wave of interest in its theoretical developments, we can observe a surge of interest in practical FM-index variants in the last few years. These enhancements are often related to a bit-vector representation, augmented with an efficient rank-handling data structure. In this work, we propose a new, cache-friendly, implementation of the rank primitive and advocate for a very ...

  18. Fundamentals of database indexing and searching

    CERN Document Server

    Bhattacharya, Arnab

    2014-01-01

    Fundamentals of Database Indexing and Searching presents well-known database searching and indexing techniques. It focuses on similarity search queries, showing how to use distance functions to measure the notion of dissimilarity.After defining database queries and similarity search queries, the book organizes the most common and representative index structures according to their characteristics. The author first describes low-dimensional index structures, memory-based index structures, and hierarchical disk-based index structures. He then outlines useful distance measures and index structures

  19. Regulatory and technical reports (abstract index journal)

    International Nuclear Information System (INIS)

    This compilation consists of bibliographic data and abstracts for the formal regulatory and technical reports issued by the US Nuclear Regulatory Commission staff and its contractors. There are four types of reports included: staff reports, conference reports, contractor reports, and international agreement reports. In addition to the main citations with abstracts, the following are also included: Secondary report number index; Personal author index; Subject index; NRC originating organization indices for staff reports and international agreement reports; NRC contract sponsor index; Contractor index; International organization index; and Licensed facility index

  20. Acoustic cloaking by a near-zero-index phononic crystal

    KAUST Repository

    Zheng, Li-Yang

    2014-04-21

    Zero-refractive-index materials may lead to promising applications in various fields. Here, we design and fabricate a near Zero-Refractive-Index (ZRI) material using a phononic crystal (PC) composed of a square array of densely packed square iron rods in air. The dispersion relation exhibits a nearly flat band across the Brillouin zone at the reduced frequency f? =?0.5443c/a, which is due to Fabry-Perot (FP) resonance. By using a retrieval method, we find that both the effective mass density and the reciprocal of the effective bulk modulus are close to zero at frequencies near the flat band. We also propose an equivalent tube network model to explain the mechanisms of the near ZRI effect. This FP-resonance-induced near ZRI material offers intriguing wave manipulation properties. We demonstrate both numerically and experimentally its ability to shield a scattering obstacle and guide acoustic waves through a bent structure.

  1. Research on Index for Assessment of Mine Ventilation Capability

    Directory of Open Access Journals (Sweden)

    Zhou Dongyi

    2015-04-01

    Full Text Available In order to perfect the current index equivalent orifice for assessment of coal mine ventilation capability checking, we put forward a new evaluation methodology to accomplish this aim based on existing research and the present practical conditions in China. In addition, indexes for calculating reasonable values of equivalent orifice for all kinds of mine ventilation systems are given. The new way is more reasonable and scientific by example. Equivalent orifice equation is analyzed and then it can be found that for the mines with different ventilation systems the calculation methods of total equivalent orifice and total windage are different. Equivalent orifice calculation needs the total amount of the return air in the mine; total windage is calculated according to the specific form of ventilation.

  2. An Ocean-Based Potential Intensity Index for Tropical Cyclones

    Science.gov (United States)

    Lin, I. I.; Black, P. G.; Price, J. F.; Yang, C.; Chen, S. S.; Chi, N.; Harr, P.; Lien, C.; D'Asaro, E. A.; Wu, C.

    2012-12-01

    Improvement in tropical cyclones' intensity prediction is an important ongoing effort. Cooling of the ocean by storm mixing reduces storm intensity by reducing the air-sea enthalpy flux. Here, we modify the widely used Sea Surface Temperature Potential Intensity (SST_PI) index by including information from the upper subsurface ocean to form a new Ocean Cooling Potential Intensity index, OC_PI. Applied to a 14-year (1998-2011) Western Pacific typhoon archive, the correlation coefficient between the predicted maximum intensity and the observed peak intensity increased from 0.08 to 0.31. For the sub group of slow-moving TCs that has the strongest interaction with subsurface ocean, r2 increases to 0.56. OC_PI thus contributes to the improvement on the existing PI through incorporation of ocean's subsurface information.

  3. Transportation environment data bank index

    International Nuclear Information System (INIS)

    In an effort to determine the environmental intensities to which shipping containers will be exposed, a ''Data Bank'' of environmental information has been established by Sandia Laboratories, Division 1542, for the ERDA Division of Waste Management and Transportation. This document is an index which can be used to request data of interest. (U.S.)

  4. Transportation environment data bank index

    International Nuclear Information System (INIS)

    In an effort to determine the environment intensities to which shipping containers will be exposed, a ''Data Bank'' of environmental information has been established by Sandia Laboratories, Division 1285 for the ERDA Division of Environmental Control Technology. This document is an index which can be used to request data of interest

  5. Index to AEC Information Booklets

    Energy Technology Data Exchange (ETDEWEB)

    None

    1978-01-01

    The U. S. Atomic Energy Commission publishes a series of information booklets for the general public. These booklets explain many aspects of nuclear science. Because these booklets cover such a variety of scientific fields, this index was prepared to help the reader find quickly those booklets that contain the information he needs.

  6. Second Training Course in Indexing

    Directory of Open Access Journals (Sweden)

    Director DESIDOC

    1981-07-01

    Full Text Available The Second Training Course in Indexing was held at DMRL, Hyderabad from 29 Dec 1980 to 8 Jan 1981. The Course was intended for information personnel of the DRDO Labs/Estts located in and around Hyderabad. Twelve trainees drawn from Technical Information Centres of DMRL, DRDL, DLRL, RTO (Dte of Aero, and NSTL participated in the Course.

  7. Automatic indexing, compiling and classification

    International Nuclear Information System (INIS)

    A review of the principles of automatic indexing, is followed by a comparison and summing-up of work by the authors and by a Soviet staff from the Moscou INFORM-ELECTRO Institute. The mathematical and linguistic problems of the automatic building of thesaurus and automatic classification are examined

  8. Mining and Indexing Graph Databases

    Science.gov (United States)

    Yuan, Dayu

    2013-01-01

    Graphs are widely used to model structures and relationships of objects in various scientific and commercial fields. Chemical molecules, proteins, malware system-call dependencies and three-dimensional mechanical parts are all modeled as graphs. In this dissertation, we propose to mine and index those graph data to enable fast and scalable search.…

  9. Transportation Environment Data Bank index

    Energy Technology Data Exchange (ETDEWEB)

    Davidson, C.A.; Foley, J.T.

    1976-11-01

    In an effort to determine the environment intensities to which energy materials in transit will be exposed, a ''Data Bank'' of environmental information has been established by Sandia Laboratories, Division 1285 for the ERDA Division of Environmental Control Technology. This document is an index which can be used to request data of interest.

  10. An index of fiscal democracy

    OpenAIRE

    Streeck, Wolfgang; Mertens, Daniel

    2010-01-01

    Over the past four decades, the accumulation of policy legacies and public debt has led to a decline in fiscal flexibility in Germany and the United States. By applying an index of fiscal democracy to Germany, the paper illustrates the associated shrinkage of democratic control over budget priorities and compares the developments in both countries.

  11. 1988 Bulletin compilation and index

    International Nuclear Information System (INIS)

    This document is published to provide current information about the national program for managing spent fuel and high-level radioactive waste. This document is a compilation of issues from the 1988 calendar year. A table of contents and one index have been provided to assist in finding information

  12. 1988 Bulletin compilation and index

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1989-02-01

    This document is published to provide current information about the national program for managing spent fuel and high-level radioactive waste. This document is a compilation of issues from the 1988 calendar year. A table of contents and one index have been provided to assist in finding information.

  13. An automatic bibliography indexing programme

    Directory of Open Access Journals (Sweden)

    J. W. Morris

    1974-12-01

    Full Text Available A relatively simple FORTRAN IV programme, designed for a small computer, for author and key-word indexes to bibliographic records is described, and examples of output are given. It is com­pared with some other systems. Suggested improvements to the programme are given.

  14. Transportation Environment Data Bank index

    International Nuclear Information System (INIS)

    In an effort to determine the environment intensities to which energy materials in transit will be exposed, a ''Data Bank'' of environmental information has been established by Sandia Laboratories, Division 1285 for the ERDA Division of Environmental Control Technology. This document is an index which can be used to request data of interest

  15. Human development index: a critique.

    Science.gov (United States)

    Chowdhury, O H

    1991-09-01

    This discussion focuses on the advantages and disadvantages of constructing a summary measure of the multidimensional and dynamic concept of development. 2 indexes are referred to: the UN Development Programme; human development index (HDI) and the Physical Quality of Life Index (PQLI). PQLI weights equally life expectancy at 1 year, infant mortality, and literacy, regardless of the correlation of variables and the arbitrariness of the weights. PQLI also is assumed to measure the quantity of life, not the quality. HDI measures quantity and quality and includes life expectancy, literacy, and real GDP/capita, and may include a measure of human freedom. Objectivity is a major problem with any index. Assignment of weights is an example of arbitrariness without justification and the index is sensitive the weights assigned. There is a paradox between defending weights on the 1 hand and, if robustness of the index is assumed and components are correlated, then any single component could suffice. A more serious criticism of the HDI is the weighting of each rank order of the country by 1/3 and summing the weighted ranking of the 3 indicators. The flaw here is the problem of application of ratio scales on ordinal magnitudes. The rank correlation coefficient between real GDP/capita and life expectancy, real GDP/capita and literacy; and literacy and life expectancy are .90, .80, and .89, respectively. HDI is also correlated with GDP/capita (.87). Composite indexes are not sensitive to variability in components or the imbalance in components, e.g., a country with low means but high literacy. The goal should continue to be to develop a conceptually and methodologically acceptable summary measure. It is suggested that a necessary component is economic development. Countries may be ranked according to their level of economic development in order to measure their achievements in human development. A weighted distribution of income/capita is a better indicator of the economic well being of a country because it reflects the maldistribution of income. Access to available government goods and services by income groups should also be taken into account. Purchasing power parity should replace income/capita in nominal prices for international comparisons due to the presence of nontradable goods and services and distortions from exchange rate anomalies, tariffs, and taxes. Thus, a replacement for HDI is purchasing power parity adjusted real income/capita weighted by the distribution of income which uses the Gini Coefficients. PMID:12317337

  16. ?????? ????????? ??????? airBaltic

    Index Scriptorium Estoniae

    2011-01-01

    Läti valitsus peab lähiajal otsustama lennufirma airBaltic likiviidsuse küsimuse. Bookinghouse'i valdav firma JSC Interno Partners teatas, et lennufirma Air Baltic segane finantsseis sunnib neid ettevõtte piletimüügi peatama

  17. Air Quality Facilities

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — Facilities with operating permits for Title V of the Federal Clean Air Act, as well as facilities required to submit an air emissions inventory, and other...

  18. AirCompare

    Data.gov (United States)

    U.S. Environmental Protection Agency — AirCompare contains air quality information that allows a user to compare conditions in different localities over time and compare conditions in the same location...

  19. Nuclear air cleaning

    International Nuclear Information System (INIS)

    This report briefly describes the history of the use of high- efficiency particulate air filters for air cleaning at nuclear installations in the United States and discusses future uses of such filters

  20. Indoor Air Pollution

    Science.gov (United States)

    We usually think of air pollution as being outdoors, but the air in your house or office could also be polluted. Sources of indoor pollution include Mold and pollen Tobacco smoke Household products ...

  1. Air Pollution Health Threats

    Medline Plus

    Full Text Available ... Videos & Tools You Are Here: Home ? Latest Health News ? Air Pollution Health Threats URL of this page: https://www.nlm.nih.gov/medlineplus/videos/news/Pollution_Health_091715.html Air Pollution Health Threats ...

  2. Evaluation of CT dose and image quality in Recife, Brazil

    International Nuclear Information System (INIS)

    The objective of this work was to perform a dosimetry study of six CT scanners located in Recife, Brazil, and to evaluate the image quality of these equipments. In this work, the volume CT air kerma index (CVOL) and the air kerma length product (PKL,CT) were estimated. These quantities were calculated using normalized weighted air kerma ind ices in CT standard dosimetry phantoms (nCW), supplied by the ImPACT group for several CT scanners, and the scanning parameters of 15 adult examinations of the head, chest, abdomen and abdomen and pelvis of each institution. The image quality tests were performed using the phantom and accreditation protocol from the American College of Radiology (ACR). The results showed a wide variation of air kerma values for the six evaluated institutions. The CVOL values for head scans varied between 11 and 59 mGy and the PKL,CT, from 49 to 545 mGy.cm. The chest examinations presented CVOL values varying from 6 to 15 mGy, and PKL,CT values between 120 and 466 mGy.cm. For abdominal scans, the estimated CVOL values varied between 5 and 14 mGy, and the PKL,CT values varied from 96 to 425 mGy.cm. The wide variation of air kerma between different centres is related to the type of scanner and also to the scanning protocol. The results also showed that, although the CVOL and PKL,CT values are compatible to the European reference levels, the image quality did not attend all ACR CT accreditation requirements. (author)

  3. Evaluation of CT dose and image quality in Recife, Brazil

    International Nuclear Information System (INIS)

    The objective of this work was to perform a dosimetry study of six CT scanners located in Recife, Brazil, and to evaluate the image quality of these equipments. In this work, the volume CT air kerma index (CVOL) and the air kerma length product (PKL,CT) were estimated. These quantities were calculated using normalized weighted air kerma ind ices in CT standard dosimetry phantoms (nCW), supplied by the ImPACT group for several CT scanners, and the scanning parameters of 15 adult examinations of the head, chest, abdomen and abdomen and pelvis of each institution. The image quality tests were performed using the phantom and accreditation protocol from the American College of Radiology (ACR). The results showed a wide variation of air kerma values for the six evaluated institutions. The CVOL values for head scans varied between 11 and 59 mGy and the PKL,CT, from 49 to 545 mGy.cm The chest examinations presented CVOL values varying from 6 to 15 mGy, and PKL,CT values between 120 and 466 mGy.cm. For abdominal scans, the estimated CVOL values varied between 5 and 14 mGy, and the PKL,CT values varied from 96 to 425 mGy.cm. The wide variation of air kerma between different centres is related to the type of scanner and also to the scanning protocol. The results also showed that, although the CVOL and PKL,CT values are compatible to the European reference levels, the image quality did not attend all ACR CT accreditation requirements. (author)

  4. An approach to represent a combined exposure to air pollution

    Directory of Open Access Journals (Sweden)

    Mieczyslaw Szyszkowicz

    2015-10-01

    Full Text Available Objectives: The objective of this study was to present a technique for estimating the effect of ambient air pollution mix on health outcomes. Material and Methods: We created a technique of indexing air pollution mix as a cause of the increased odds of health problems. As an illustrative example, we analyzed the impact of pollution on the frequency of emergency department (ED visits due to colitis among young patients (age < 15 years, N = 11 110. Our technique involves 2 steps. First, we considered 6 ambient air pollutants (carbon monoxide, nitrogen dioxide, sulphur dioxide, ozone, and 2 measures of particulate matter treating each pollutant as a single exposure. Odds ratios (ORs for ED visits associated with a standard increase (interquartile range – IQR in the pollutants levels were calculated using the case-crossover technique. The ORs and their 95% confidence intervals (95% CIs were also found for lagged exposures (for lags 1–9 days. Second, we defined a Health Air Study Index (HASI to represent the combined impact of the 6 air pollutants. Results: We obtained positive and statistically significant results for individual air pollutants and among them the following estimations: OR = 1.06 (95% CI: 1.02–1.1, NO2 lag 3, IQR = 12.8 ppb, OR = 1.04 (95% CI: 1.01–1.07, SO2 lag 4, IQR = 2.3 ppb, OR = 1.04 (95% CI: 1–1.06, PM lag 3, IQR = 6.2 ?g/m3. Among the re-calculated ORs with the HASI values as an exposure, the highest estimated value was OR = 1.37 (95% CI: 1.12–1.68, for 1 unit of the HASI, lag 3. Conclusions: The proposed index (HASI allows to confirm the pattern of associations for lags obtained for individual air pollutants. In the presented example the used index (HASI indicates the strongest relation with the exposure lagged by 3 days.

  5. Experimental technique of calibration of symmetrical air pollution models

    Indian Academy of Sciences (India)

    P Kumar

    2005-10-01

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

  6. Indoor air quality

    DEFF Research Database (Denmark)

    Jensen, Trine Susanne; Recevska, Ieva

    2009-01-01

     The objective of the 35th specific agreement is to provide support to the EEA activities in Environment and Health (E&H) on the topic of indoor air quality. The specific objectives have been to provide an overview of indoor air related projects in EU and indoor air related policies as well as idenfiying "good practices" to reduce health impact of indoor air exposure and suggest areas for future improvements.

  7. Air-quality atlas

    International Nuclear Information System (INIS)

    An atlas with maps that show the nation's air quality monitoring network and how air quality varies across the country is presented in the pamphlet. The atlas focuses on air concentrations that are direct measurements of pollutant concentrations at monitoring sites throughout the country. Pollutant emission values are based on best engineering estimates of the total tonnage of these pollutants released into the air annually

  8. Characterizing multi-pollutant air pollution in China: Comparison of three air quality indices.

    Science.gov (United States)

    Hu, Jianlin; Ying, Qi; Wang, Yungang; Zhang, Hongliang

    2015-11-01

    Multi-pollutant air pollution (i.e., several pollutants reaching very high concentrations simultaneously) frequently occurs in many regions across China. Air quality index (AQI) is used worldwide to inform the public about levels of air pollution and associated health risks. The current AQI approach used in China is based on the maximum value of individual pollutants, and does not consider the combined health effects of exposure to multiple pollutants. In this study, two novel alternative indices--aggregate air quality index (AAQI) and health-risk based air quality index (HAQI)--were calculated based on data collected in six megacities of China (Beijing, Shanghai, Guangzhou, Shjiazhuang, Xi'an, and Wuhan) during 2013 to 2014. Both AAQI and HAQI take into account the combined health effects of various pollutants, and the HAQI considers the exposure (or concentration)-response relationships of pollutants. AAQI and HAQI were compared to AQI to examine the effectiveness of the current AQI in characterizing multi-pollutant air pollution in China. The AAQI and HAQI values are higher than the AQI on days when two or more pollutants simultaneously exceed the Chinese Ambient Air Quality Standards (CAAQS) 24-hour Grade II standards. The results of the comparison of the classification of risk categories based on the three indices indicate that the current AQI approach underestimates the severity of health risk associated with exposure to multi-pollutant air pollution. For the AQI-based risk category of 'unhealthy', 96% and 80% of the days would be 'very unhealthy' or 'hazardous' if based on AAQI and HAQI, respectively; and for the AQI-based risk category of 'very unhealthy', 67% and 75% of the days would be 'hazardous' if based on AAQI and HAQI, respectively. The results suggest that the general public, especially sensitive population groups such as children and the elderly, should take more stringent actions than those currently suggested based on the AQI approach during high air pollution events. Sensitivity studies were conducted to examine the assumptions used in the AAQI and HAQI approaches. Results show that AAQI is sensitive to the choice of pollutant irrelevant constant. HAQI is sensitive to the choice of both threshold values and pollutants included in total risk calculation. PMID:26197060

  9. Regional Air Quality Forecasting for the Czech Republic.

    Czech Academy of Sciences Publication Activity Database

    Corbet, L; Vl?ek, O.; Eben, Kryštof; Liczki, Jitka; Benešová, N.; Modlík, M.

    Aarhus University, 2013, s. 1-5. [HARMO 15. Madrid (ES), 06.05.2013-09.05.2013] Institutional support: RVO:67985807 Keywords : air quality forecast * CTM * emissions * verification Subject RIV: DG - Athmosphere Sciences, Meteorology http://www.harmo.org/Conferences/Proceedings/_Madrid/topicIndex.asp?topicID=0

  10. Air-compatible Broadband Angular Selective Material Systems

    OpenAIRE

    Shen, Yichen; Hsu, Chia-Wei; Joannopoulos, John D.; Solja?i?, Marin

    2015-01-01

    An optical broadband angular selective filter achieved by stacking of one-dimensional photonic crystals has promising potential in various applications. In this report, we demonstrate the first experimental realization of an optical broadband angular selective filter capable of operation in air, in contrast to our previous demonstration in index matching liquid.

  11. Indoor Air Quality Manual.

    Science.gov (United States)

    Baldwin Union Free School District, NY.

    This manual identifies ways to improve a school's indoor air quality (IAQ) and discusses practical actions that can be carried out by school staff in managing air quality. The manual includes discussions of the many sources contributing to school indoor air pollution and the preventive planning for each including renovation and repair work,…

  12. Air Sensor Guidebook

    Science.gov (United States)

    This Air Sensor Guidebook has been developed by the U.S. EPA to assist those interested in potentially using lower cost air quality sensor technologies for air quality measurements. Its development was in direct response to a request for such a document following a recent scienti...

  13. Air Pollution Training Programs.

    Science.gov (United States)

    Public Health Service (DHEW), Rockville, MD.

    This catalog lists the universities, both supported and not supported by the Division of Air Pollution, which offer graduate programs in the field of air pollution. The catalog briefly describes the programs and their entrance requirements, the requirements, qualifications and terms of special fellowships offered by the Division of Air Pollution.…

  14. Silicon photonic crystal nanostructures for refractive index sensing

    DEFF Research Database (Denmark)

    Dorfner, Dominic; Hürlimann, T.; Zabel, T.; Frandsen, Lars Hagedorn; Abstreiter, G.; Finley, J.J.

    2008-01-01

    The authors present the fabrication and optical investigation of Silicon on Insulator photonic crystal drop-filters for use as refractive index sensors. Two types of defect nanocavities (L3 and H1-r) are embedded between two W1 photonic crystal waveguides to evanescently route light at the cavity mode frequency between input and output waveguides. Optical characterization of the structures in air and various liquids demonstrate detectivities in excess of n=n = 0:018 and n=n = 0:006 for the H1-r ...

  15. High-index-contrast subwavelength grating VCSEL

    DEFF Research Database (Denmark)

    Gilet, Philippe; Olivier, Nicolas

    2010-01-01

    In this article, we report our results on 980nm high-index-contrast subwavelength grating (HCG) VCSELs for optical interconnection applications. In our structure, a thin undoped HCG layer replaces a thick p-type Bragg mirror. The HCG mirror can feasibly achieve polarization-selective reflectivities close to 100%. The investigated structure consists of a HCG mirror with an underneath /4-thick oxide gap, four p-type GaAlAs/GaAs pairs for current spreading, three InGaAs/GaAs quantum wells, and an n-type GaAlAs/GaAs Bragg mirror. The HCG structure was defined by e-beam lithography and dry etching. The current oxide aperture and the oxide gap underneath the HCG were simultaneously formed by the selective wet oxidation process. Compared to air-gap high contrast grating mirrors demonstrated elsewhere, our grating mirrors are particular since they are supported by thinner /4 aluminium oxide layer, and thus are mechanically robust and thinner than usual designs. Sub-milliamp threshold currents and single-transverse-mode operation was obtained. A hero device exhibited maximum singlemode output power of more than 4 mW at room temperature and 1 mw at 70°C, which are the highest values ever reported from the HCG structures. These results build a bridge between a standard VCSEL and a hybrid laser on silicon, making them of potential use for the realization of silicon photonics.

  16. Refractive index determination in length measurement by two-colour interferometry

    International Nuclear Information System (INIS)

    A well-known method for compensation of the refractive index of air for length measurements based on the speed of light is a measurement with two different wavelengths and using the dispersion relation. No measurement of temperature, pressure and CO2 content of the air is necessary. However, this method is valid only for dry air and is practically not used. For moist air the partial pressure of water vapour has to be known as the only air parameter for the compensation of the refractive index. In practice it is not possible to measure the partial pressure of water vapour in air directly. Standard hygrometers indicate the relative humidity. To get the partial pressure the temperature has to be known. Experiments were performed with this modified compensation method where the air pressure and the humidity are measured conventionally. A homodyne interferometer was set up with a frequency doubled Nd:YVO4 laser with the wavelengths 1064 nm and 532 nm. The effective temperature in the measurement path is derived from the length results for both wavelengths. Our experiments indicate a length-dependent measurement uncertainty of below 1.2 × 10?7L for distances up to 30 m

  17. 1060-nm Tunable Monolithic High Index Contrast Subwavelength Grating VCSEL

    DEFF Research Database (Denmark)

    Ansbæk, Thor; Chung, Il-Sug

    2013-01-01

    We present the first tunable vertical-cavity surface-emitting laser (VCSEL) where the top distributed Bragg reflector has been completely substituted by an air-cladded high-index-contrast subwavelength grating (HCG) mirror. In this way, an extended cavity design can be realized by reducing the reflection at the semiconductor #x2013;air interface using an anti-reflective coating (ARC). We demonstrate how the ARC can be integrated in a monolithic structure by oxidizing AlGaAs with high Al-content. The HCG VCSEL has the potential to achieve polarization stable single-mode output with high tuning efficiency. The HCG VCSEL shows a total tuning range of 16 nm around an emission wavelength of 1060 nm with 1-mW output power.

  18. AIR QUALITY IMPACTS OF LIQUEFIED NATURAL GAS IN THE SOUTH COAST AIR BASIN OF CALIFORNIA

    Energy Technology Data Exchange (ETDEWEB)

    Carerras-Sospedra, Marc; Brouwer, Jack; Dabdub, Donald; Lunden, Melissa; Singer, Brett

    2011-07-01

    The effects of liquefied natural gas (LNG) on pollutant emission inventories and air quality in the South Coast Air Basin of California were evaluated using recent LNG emission measurements by Lawrence Berkeley National Laboratory and the Southern California Gas Company (SoCalGas), and with a state-of-the-art air quality model. Pollutant emissions can be affected by LNG owing to differences in composition and physical properties, including the Wobbe index, a measure of energy delivery rate. This analysis uses LNG distribution scenarios developed by modeling Southern California gas flows, including supplies from the LNG receiving terminal in Baja California, Mexico. Based on these scenarios, the projected penetratino of LNG in the South Coast Air Basin is expected to be limited. In addition, the increased Wobbe index of delivered gas (resulting from mixtures of LNG and conventional gas supplies) is expected to cause increases smaller than 0.05 percent in overall (area-wide) emissions of nitrogen oxides (NOx). BAsed on the photochemical state of the South Coast Air Basin, any increase in NOx is expected to cause an increase in the highest local ozone concentrations, and this is reflected in model results. However, the magnitude of the increase is well below the generally accepted accuracy of the model and would not be discernible with the existing monitoring network. Modeling of hypothetical scenarios indicates that discernible changes to ambient ozone and particulate matter concentrations would occur only at LNG distribution rates that are not achievable with current or planned infrastructure and with Wobbe index vlaues that exceed current gas quality tariffs. Results of these hypothetical scenarios are presented for consideration of any proposed substantial expansion of LNG supply infrastructure in Southern California.

  19. Index

    Directory of Open Access Journals (Sweden)

    Antonio Juan Sánchez

    2013-08-01

    Full Text Available The Advances in Distributed Computing and Artificial Intelligence Journal (ADCAIJ is an open access journal that publishes articles which contribute new results associated with distributed computing and artificial intelligence,and their application in different areas.The artificial intelligence is changing our society. Its application in distributed environments, such as the Internet, electronic commerce, mobile communications, wireless devices, distributed computing and so on, is increasing and becoming and element of high added value and economic potential in industry and research. These technologies are changing constantly as a result of the large research and technical effort being undertaken in both universities and businesses. The exchange of ideas between scientists and technicians from both academic and business areas is essential to facilitate the development of systems that meet the demands of today's society.We would like to thank all the contributing authors for their hard and highly valuable work. Their work has helped to contribute to the success of this special issue. Finally, the Editors wish to thank Scientific Committee of Advances in Distributed Computing and Artificial Intelligence Journal for the collaboration of this special issue, that notably contributes to improve the quality of the journal. We hope the reader will share our joy and find this special issue very useful.

  20. Index

    Directory of Open Access Journals (Sweden)

    Antonio Juan SÁNCHEZ

    2013-05-01

    Full Text Available The Advances in Distributed Computing and Artificial Intelligence Journal (ADCAIJ is an open access journal that publishes articles which contribute new results associated with distributed computing and artificial intelligence,and their application in different areas. The artificial intelligence is changing our society. Its application in distributed environments, such as the Internet, electronic commerce, mobile communications, wireless devices, distributed computing and so on, is increasing and becoming and element of high added value and economic potential in industry and research. These technologies are changing constantly as a result of the large research and technical effort being undertaken in both universities and businesses. The exchange of ideas between scientists and technicians from both academic and business areas is essential to facilitate the development of systems that meet the demands of today's society. We would like to thank all the contributing authors for their hard and highly valuable work. Their work has helped to contribute to the success of this special issue. Finally, the Editors wish to thank Scientific Committee of Advances in Distributed Computing and Artificial Intelligence Journal for the collaboration of this special issue, that notably contributes to improve the quality of the journal. We hope the reader will share our joy and find this special issue very useful.