• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 9
  • 4
  • 4
  • 2
  • 1
  • Tagged with
  • 23
  • 23
  • 12
  • 9
  • 6
  • 4
  • 4
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Dosimetria de sup(222)Rn no ar em ambientes localizados acima e abaixo do nível do solo / Dosimetry of sup(222)Rn in the air in environments located above and below ground level

CAZULA, CAMILA D. 11 June 2015 (has links)
Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2015-06-11T17:49:32Z No. of bitstreams: 0 / Made available in DSpace on 2015-06-11T17:49:32Z (GMT). No. of bitstreams: 0 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A exposição da população em geral à radiação ionizante surge principalmente a partir de fontes naturais. A principal contribuição é decorrente da inalação do radônio (Rn-222), um gás que ocorre naturalmente (UNSCEAR, 2000). A concentração de Rn-222 num ambiente é controlada por fatores como a permeabilidade do solo e teor de água, a variabilidade meteorológica, características de construção da fundação e da pressão diferencial positivo habitual entre o solo e o ambiente interno. Estudos indicam que a concentração de radônio, apresenta uma variação significativa no subsolo, térreo e andares superiores das edificações. O objetivo deste estudo é determinar os níveis de radônio, nos subsolos, térreos e andares acima do nível do solo, em uma universidade na cidade de São Paulo e um edifício residencial na cidade de Peruíbe. As medidas de Rn-222 foram realizadas através do método passivo com detectores de traços nucleares de estado sólido (CR-39). Os ambientes estudados apresentam concentrações de Rn-222 bastante inferiores aos valores recomendados pela Comissão Internacional de Proteção Radiológica, publicados no documento de 2009, de 300 Bq/m3 para residências e 1000 Bq/m3 para locais de trabalho. No edifício residencial na cidade de Peruíbe, analisaram-se ainda, as concentrações de Ra-266, Th-232 e K-40 em materiais de construção utilizados na construção do edifício, por meio de espectrometria gama. A dose efetiva total para o morador devido à exposição externa foi de 0,8 mSv a-1, inferior ao limite de dose anual para público em geral de 1 mSv a-1. / Dissertação (Mestrado em Tecnologia Nuclear) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP / FAPESP:13/01841-9
12

A Study Of Central Florida Nonroad Voc And Nos Emissions And Potential Actions To Reduce Emissions

Radford, Michael 01 January 2009 (has links)
Ground-level ozone is harmful to the human respiratory system, as well as the environment. The national EPA 8-hour ozone standard for ground-level ozone was reduced from 85 parts per billion (ppb) to 75 ppb in 2008, and trends from previous years show that some of the counties in Central Florida could be in danger of violation. Violation means "non attainment" status; in which the county is ordered by EPA to develop specific implementation plans to reduce its emissions. The objective of this study was to compile an emissions inventory of volatile organic compounds (VOCs) and nitrogen oxides (NOx) from nonroad equipment in Osceola, Seminole, and Orange Counties (OSO) in Central Florida, and to develop possible action steps to reduce those emissions. This is important because VOC and NOx emissions are precursors to ground-level ozone. Thus, compiling emissions inventories is important to identify high VOC and NOx emitters. Mobile and point sources have long been the highest emitters of VOC and NOx and have therefore been targeted and monitored since the Clean Air Act of 1970, but the nonroad sources (such as construction and lawn equipment) have only been regulated since the 1990s. Using the NONROAD and NMIM modeling programs, the highest nonroad emitters of VOC for Central Florida were found to be lawn/garden equipment, and boating equipment, emitting a combined percentage of 77% of the total nonroad mobile source VOC. Construction equipment contributed 67% of the total nonroad mobile source emissions of NOx in Central Florida. The components of these categories were also analyzed to find the largest individual sources of VOC and NOx. Of the individual sources, lawn mowers and outboard boat engines were found to be the largest sources of VOCs. Of the NOx sources, all the construction equipment components had a relatively similar level of NOx emissions. Next, action steps were developed to reduce emissions, focusing on the high emitters, along with an estimated cost and feasibility for each measure. Of these steps, implementing a ban on leafblowers, and reducing use of lawn mowers, edgers, trimmers, etc. seemed to be the most effective for reducing VOCs. Although these are effective measures, the cost and feasibility of both pose challenges. The best action step for reducing NOx emissions in construction equipment seemed to be by simply reducing idling of equipment on job sites. This also poses challenges in feasibility and enforcement by management. Further, constant on/off cycles could result in decreasing the useful life of the older construction equipment. Finally, a survey was conducted with various construction managers and companies to find out the typical equipment and quantity needed for land clearing/grubbing, as well as the typical use, idling time, and total project time for each piece of equipment on a 10-acre site, under various conditions. The purpose of the study was to develop a rough estimate for the average amount of VOC and NOx emissions that will be produced per acre of land clearing activities, and to estimate the emissions reductions and cost savings if idling of the equipment was reduced.
13

Effects of Orientation Change on Spatial Learning of Novel Environments on Younger and Older Adults

Fox, Michael J. January 2014 (has links)
No description available.
14

Uncertainty in Regional Air Quality Modeling

Digar, Antara 05 September 2012 (has links)
Effective pollution mitigation is the key to successful air quality management. Although states invest millions of dollars to predict future air quality, the regulatory modeling and analysis process to inform pollution control strategy remains uncertain. Traditionally deterministic ‘bright-line’ tests are applied to evaluate the sufficiency of a control strategy to attain an air quality standard. A critical part of regulatory attainment demonstration is the prediction of future pollutant levels using photochemical air quality models. However, because models are uncertain, they yield a false sense of precision that pollutant response to emission controls is perfectly known and may eventually mislead the selection of control policies. These uncertainties in turn affect the health impact assessment of air pollution control strategies. This thesis explores beyond the conventional practice of deterministic attainment demonstration and presents novel approaches to yield probabilistic representations of pollutant response to emission controls by accounting for uncertainties in regional air quality planning. Computationally-efficient methods are developed and validated to characterize uncertainty in the prediction of secondary pollutant (ozone and particulate matter) sensitivities to precursor emissions in the presence of uncertainties in model assumptions and input parameters. We also introduce impact factors that enable identification of model inputs and scenarios that strongly influence pollutant concentrations and sensitivity to precursor emissions. We demonstrate how these probabilistic approaches could be applied to determine the likelihood that any control measure will yield regulatory attainment, or could be extended to evaluate probabilistic health benefits of emission controls, considering uncertainties in both air quality models and epidemiological concentration–response relationships. Finally, ground-level observations for pollutant (ozone) and precursor concentrations (oxides of nitrogen) have been used to adjust probabilistic estimates of pollutant sensitivities based on the performance of simulations in reliably reproducing ambient measurements. Various observational metrics have been explored for better scientific understanding of how sensitivity estimates vary with measurement constraints. Future work could extend these methods to incorporate additional modeling uncertainties and alternate observational metrics, and explore the responsiveness of future air quality to project trends in emissions and climate change.
15

Priežemio ozono koncentracijos sklaida Kauno mieste ir jos ryšys su meteorologinėmis sąlygomis / Distribution of ground level ozone concentration in Kaunas ant its relationship with meteorogical parameters

Šiuipys, Nerijus 10 August 2009 (has links)
Viena didžiausių problemų, atsirandančių dėl oro taršos miestų ore, yra tarša, sukelta fotocheminių oksidantų, tarp jų, ir priežemio ozono. Darbo tikslas: nustatyti priežemio ozono koncentracijos sklaidą Kauno mieste ir jos ryšį su meteorologinėmis sąlygomis. Tyrimai buvo vykdomi 2006 - 2009 metais. Darbo objektas - Kauno miestas. Visoje miesto teritorijoje priežemio ozono koncentracija buvo matuota 10 skirtingų matavimo vietų. Ozono koncentracijai nustatyti buvo naudotas „Aeroqual 300 Series” ozono matuoklis. Priežemio ozono koncentracija buvo matuota vidudienį nuo 12 iki 14 ir vakare nuo 17 iki 19 valandos. Kiekvienoje vietoje buvo atlikta nuo 4 - 6 matavimų, kiekvieno sezono metu. Tyrimų metu nustatyta, kad priežemio ozono koncentracijos pasiskirstymas kiekvieno sezono metu yra skirtingas. Didžiausia vidutinė sezoninė priežemio ozono koncentracija buvo nustatyta pavasario - vasaros sezonų metu (72 g/m3), o mažiausia žiemos sezono metu (7 g/m3). 2009 m. pavasario sezono metu Vileikos g., prie GMF nustatyta didžiausia vienkartinė priežemio ozono koncentracija (128 g/m3). Buvo vertintas priežemio ozono koncentracijos ryšys su meteorologinėmis sąlygomis ir azoto oksidų (NOx) koncentracija. Gauti rezultatai parodė, statistiškai reikšmingą teigiamą ryšį tarp ozono koncentracijos ir temperatūros (r = 0,73; p = 0,00) ir NO2 koncentracijos (r = 0,48; p = 0,03). Tai rodo, kad didėjant temperatūrai ir NO2 koncentracijai, didėja ir priežemio ozono koncentracija. Tarp priežemio... [toliau žr. visą tekstą] / One of the major problems resulting from air pollution of the urban area, is the pollution caused by photochemical oxidants, among their, ground level ozone. The aim of this work was to assess distribution of ground level ozone concentration in Kaunas and its relationship to meteorological situation. Measurements was carried out in 2006 - 2009. Object of work has been selected Kaunas city. Throughout the city area ground level ozone concentration was measured by a sampling scheme for the 10 different measurement points. For determinate of ground level ozone concentration, we used ozone quality monitor „Aeroqual 300 Series“. Ground level ozone concentration was measured at midday from 12 to 14 and in the evening from 17 to 19 hours. Each site was carried out from 4 - 6 measurements. Study rezults revealed, that ground level ozone concentration distribution of each season is different. The maximum average ozone concentration was found in spring - summer season (72 g/m3), and the lowest in winter season (7 g/m3). The higher ground level ozone concentration episode (128 g/m3) was stated in spring season in 2009 year. Relationship between ground level ozone concentration and meteorological situations and nitrogen oxides (NOx) concentration was evaluated. The results showed statistically significant positive relationship between ozone concentration and temperature (r = 0,73; p = 0,00) and NO2 concentration (r = 0,48; p = 0,03). Between ground level ozone concentration and wind... [to full text]
16

Artificial radionuclides and their interaction with aerosol particles in the Ignalina NPP and its environment / Dirbtiniai radionuklidai ir jų sąveika su aerozolio dalelėmis Ignalinos AE ir jos aplinkoje

Rožkov, Andrej 28 December 2009 (has links)
Investigations on the determination of 137Cs sources in the Ignalina NPP environment air and the evaluation of changes of the long-term trend of 137Cs activity concentrations in the Ignalina NPP ground-level air were carried out in this dissertation. Radionuclide activity concentrations in the air and deposition were measured in the Ignalina NPP impact zone in 2004-2009. Results show, that in recent years annual 137Cs activity concentrations in the ground-level air in the Ignalina NPP region change with the half-time of 30 years. Observed episodic increases in 137Cs activity concentrations in the air correlate well with air mass transport trajectories that intersect territories, polluted with 137Cs after the accident at the Chernobyl NPP. The growth of radioactive aerosol particles in the oversaturated water vapour of the operating RBMK reactor has been investigated. In the one contour nuclear power plant coolant water steam, noble gas radionuclides decay into alkaline and earth-alkali metals, which become condensation nuclei and due to the absorption of water molecules in several minutes grow into radioactive aerosol particles. The classical method of the radionuclide activity determination in aerosol particle samples, collected on filters, was supplemented with experiments on the leaching of aerosol particles using the distilled water and measurements of radionuclide activities in samples before and after the experiment. Results show that the quantity of 137Cs and 60Сo in... [to full text] / Disertacijoje nustatyti 137Cs patekimo į Ignalinos AE aplinkos orą šaltiniai ir įvertinti ilgamečiai 137Cs aktyvumo koncentracijų ore pokyčiai. Radionuklidų aktyvumo koncentracijos ore ir iškritose matuotos nuo 2004 iki 2009 metų Ignalinos AE poveikio zonoje. Gauta, kad metinės 137Cs aktyvumo koncentracijos pažemio ore pastaraisiais metais kinta su 30 metų mažėjimo pusiau trukme. Stebėta, kad šuoliški 137Cs aktyvumo koncentracijų pažemio ore padidėjimai koreliuoja su oro masių pernašos trajektorijomis, kertančiomis teritorijas, užterštas po avarijos Černobylio AE. Nustatytas radioaktyvių aerozolio dalelių augimas prisotintuose vandens garuose veikiančio RBMK reaktoriaus kondensatoriuje. Vieno kontūro atominės elektrinės aušinamame vandens gare inertinių dujų radionuklidai, skildami virsta šarminių ir žemės šarminių metalų elementais, tampa aerozolio gamybos centrais, absorbuoja vandens molekules ir per keliolika minučių ant jų, kaip kondensacijos branduolių, išauga radioaktyvios aerozolio dalelės. Klasikinis radionuklidų aktyvumo aerozolio dalelių, surinktų filtrais, bandiniuose nustatymas papildytas išplovimo distiliuotu vandeniu eksperimentais, matuojant radionuklidų aktyvumą bandiniuose iki ir po eksperimento. Gauta, kad 137Cs ir 60Сo dalis aerozolio dalelių, surinktų veikiančio reaktoriaus ventiliaciniame ore, tirpioje frakcijoje buvo 74 17 %, atitinkamai, o neveikiančio reaktoriaus ventiliaciniame ore 22 % ir 67  5 %. 60Co aktyvumo koncentracijos AE fakele... [toliau žr. visą tekstą]
17

Dirbtiniai radionuklidai ir jų sąveika su aerozolio dalelėmis Ignalinos AE ir jos aplinkoje / Artificial radionuclides and their interaction with aerosol particles in the Ignalina NPP and its environment

Rožkov, Andrej 28 December 2009 (has links)
Disertacijoje nustatyti 137Cs patekimo į Ignalinos AE aplinkos orą šaltiniai ir įvertinti ilgamečiai 137Cs aktyvumo koncentracijų ore pokyčiai. Radionuklidų aktyvumo koncentracijos ore ir iškritose matuotos nuo 2004 iki 2009 metų Ignalinos AE poveikio zonoje. Gauta, kad metinės 137Cs aktyvumo koncentracijos pažemio ore pastaraisiais metais kinta su 30 metų mažėjimo pusiau trukme. Stebėta, kad šuoliški 137Cs aktyvumo koncentracijų pažemio ore padidėjimai koreliuoja su oro masių pernašos trajektorijomis, kertančiomis teritorijas, užterštas po avarijos Černobylio AE. Nustatytas radioaktyvių aerozolio dalelių augimas prisotintuose vandens garuose veikiančio RBMK reaktoriaus kondensatoriuje. Vieno kontūro atominės elektrinės aušinamame vandens gare inertinių dujų radionuklidai, skildami virsta šarminių ir žemės šarminių metalų elementais, tampa aerozolio gamybos centrais, absorbuoja vandens molekules ir per keliolika minučių ant jų, kaip kondensacijos branduolių, išauga radioaktyvios aerozolio dalelės. Klasikinis radionuklidų aktyvumo aerozolio dalelių, surinktų filtrais, bandiniuose nustatymas papildytas išplovimo distiliuotu vandeniu eksperimentais, matuojant radionuklidų aktyvumą bandiniuose iki ir po eksperimento. Gauta, kad 137Cs ir 60Сo dalis aerozolio dalelių, surinktų veikiančio reaktoriaus ventiliaciniame ore, tirpioje frakcijoje buvo 74  22 % ir 67  17 %, atitinkamai, o neveikiančio reaktoriaus ventiliaciniame ore – 24  5 % ir 20  5 %. 60Co aktyvumo koncentracijos AE... [toliau žr. visą tekstą] / Investigations on the determination of 137Cs sources in the Ignalina NPP environment air and the evaluation of changes of the long-term trend of 137Cs activity concentrations in the Ignalina NPP ground-level air were carried out in this dissertation. Radionuclide activity concentrations in the air and deposition were measured in the Ignalina NPP impact zone in 2004-2009. Results show, that in recent years annual 137Cs activity concentrations in the ground-level air in the Ignalina NPP region change with the half-time of 30 years. Observed episodic increases in 137Cs activity concentrations in the air correlate well with air mass transport trajectories that intersect territories, polluted with 137Cs after the accident at the Chernobyl NPP. The growth of radioactive aerosol particles in the oversaturated water vapour of the operating RBMK reactor has been investigated. In the one contour nuclear power plant coolant water steam, noble gas radionuclides decay into alkaline and earth-alkali metals, which become condensation nuclei and due to the absorption of water molecules in several minutes grow into radioactive aerosol particles. The classical method of the radionuclide activity determination in aerosol particle samples, collected on filters, was supplemented with experiments on the leaching of aerosol particles using the distilled water and measurements of radionuclide activities in samples before and after the experiment. Results show that the quantity of 137Cs and 60Сo in... [to full text]
18

Systém pro určování nadzemní výšky letajících objektů / System for Identifying Above Ground Level of Flying Objects

Boba, Peter January 2016 (has links)
This master's thesis deals with design and development of a system for measuring altitude (height above ground level) of flying objects. It describes theoretical background related to altitude measurements in avionics as well as various techniques of altitude measuring. The measurement is conducted by HMD (Height measuring device) - embedded system which uses barometric pressure sensor to measure altitude. The main part of this thesis is dedicated to ground unit - a server running custom set of applications. Using this server and radio link, it is possible to send control commands to HMD, receive data, and propagate data into web application. Furthermore server acts as a data storage and is able to process and analyse data. The thesis also discusses the precision of the measurement and the data output. System was tested and used during several glider aerobatics competitions.
19

Development of Risk Assessment Framework and Policy Recommendation for Improving Social Resilience / 社会的レジリエンスを改善するためのリスク評価フレームワークの開発と政策的提言

Fujita, Moe 23 March 2022 (has links)
学位プログラム名: 京都大学大学院思修館 / 京都大学 / 新制・課程博士 / 博士(総合学術) / 甲第24056号 / 総総博第25号 / 新制||総総||4(附属図書館) / 京都大学大学院総合生存学館総合生存学専攻 / (主査)教授 山敷 庸亮, 教授 寶 馨, 教授 池田 裕一, 佐藤 達彦 / 学位規則第4条第1項該当 / Doctor of Philosophy / Kyoto University / DFAM
20

Lygiavertės dozės galios kaitos pažemio ore šalia Lietuvos magistralių tyrimas / Equivalent dose rate variation research in the ground air by the Lithuanian highways

Gaponovienė, Kristina Živilė 16 June 2005 (has links)
This research deals with equivalent dose rate (EDR) in the ground level air caused by gamma radiation. Weighting factor for gamma radiation is equal one, so EDR in the ground air is identical absorbed ionic radiation dose. Highways A6 Kaunas-Zarasai and A11 Panevėžys-Šiauliai-Palanga were investigated. In this research the main parameters determining the level of equivalent dose rate in the ground air by the Lithuanian highways have been defined and analyzed. The objective of this research is to measure EDR in the ground air by the Lithuanian highways and compare to adequate average regional and with reference to modulation values evaluate variation reasons. In the expeditions EDR in the ground air was measured in winter and in summer. Samples of soil and asphalt were examined with gamma spectrometer and analyze presented. There was determined the dependence of EDR in the ground air from soil composition, floral or snow cover and distance to the asphalt cover. Cosmic radiation impact on EDR formation is equal to all locations. Natural origin radionuclides in soil gamma radiation have the main influence to EDR formation in the ground air. Modeling program VISIPLAN was used to define impact of radionuclides radiation in asphalt cover to EDR formation in the roadside zone. Modeling program InterRAS was used to define EDR in the ground air formation from gamma radiation of radionuclide in soil.

Page generated in 0.0204 seconds