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  • 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.
1

Caracterização das propriedades ópticas de partículas inaláveis na cidade de Cubatão - SP / Characterization of the optical properties inhalable particle in the city of Cubatão - SP

Araújo, Elaine Cristina 19 February 2019 (has links)
Os níveis de poluição do ar, tanto mundialmente, como no Brasil, principalmente em grandes metrópoles como São Paulo, dentre outras capitais e cidades brasileiras são altos e acima do que se é esperado para uma boa qualidade do ar. Uma das cidades brasileiras que ficou conhecida nacionalmente e até mundialmente pelos altos níveis de Poluentes foi Cubatão. Localizada no estado de São Paulo, a 57 km da capital do estado, Cubatão ainda tem altos níveis de Poluentes, entre eles o Material Particulado, o qual é um dos mais presentes. Dentre as classificações do material particulado estão as partículas inaláveis (MP10) e partículas inaláveis finas (MP2,5), estes são assim classificados de acordo com seus diâmetros aerodinâmicos. Tendo em vista os fatos citados acima, este trabalho propõe caracterizar as propriedades ópticas das partículas inaláveis na cidade de Cubatão - SP. Para tal foram utilizados dados de concentração das partículas inaláveis da Companhia Ambiental do Estado de São Paulo - CETESB e as informações a respeito de perfil espacial foram observadas pela técnica de sensoriamento remoto - Light Detection and Ranging - LIDAR por meio de campanhas realizadas em agosto de 2016. Também foram analisados dados de Aerosol Optical Depth - AOD extraídos da plataforma - Goddard Interactive Online Visualization And Analysis Infrastructure - GIOVANNI, a qual contém informações de satélites, que foram usadas para indicar o tamanho das partículas detectadas na região de Cubatão. Do mesmo modo verificou-se os dados do Expoente de Ångström que são distribuídos pela plataforma GIOVANNI. / The levels of air pollution, both globally and in Brazil, especially in large metropolises such as São Paulo, among other Brazilian cities and capitals are high and above what is expected for good air quality. One of the Brazilian cities that was known nationally and even worldwide by the high levels of Pollutants was Cubatão. This city is located in the state of São Paulo, 57 km from the state capital. Cubatão still has high levels of Pollutants, among them the Particulate Material, which is one of the most present. Among the classifications of the particulate material are inhalable particles (PM10) and fine inhalable particles (PM2.5), these are thus classified according to their aerodynamic diameters. In view of the facts mentioned above, this paper proposes to characterize the optical properties of inhalable particles in the city of Cubatão - SP. For this purpose, the inhalable particulate concentration data of the Environmental Company of the State of São Paulo - CETESB were used and the information regarding the spatial profile was observed by the remote sensing technique - Light Detection and Ranging - LIDAR through campaigns carried out in August, Aerosol Optical Depth - AOD data from the Goddard Interactive Online Visualization And Analysis Infrastructure (GIOVANNI) platform, which contains information from satellites, were used to indicate the size of the particles detected in the Cubatão region. In the same way the data of the Ångström exponent, distributed by GIOVANNI platform was verified.
2

Seasonality and sources of light-absorbing aerosols at Summit, Greenland

Hu, Jason 21 September 2015 (has links)
The Greenland ice sheet (GIS) is a key component of the warming Arctic climate, having the potential to dramatically influence sea level through melting. Light-absorbing aerosols are thought to be significant contributors to warming in the Arctic, because of their effect on the radiation balance through both aerosol absorption in the atmosphere as well as absorption in surface snow after particulate deposition. At this time it is not possible to estimate the impact of aerosol absorption on the radiation balance over Greenland due to the lack of in-situ measurements. Here, we present time series and estimates of key aerosol optical properties in order to better understand the seasonality and sources of aerosols over central Greenland, and compare their values with other Arctic sites. In-situ measurements made at Summit, Greenland from May 8, 2011 to December 31, 2014 include aerosol light absorption coefficient (σap) and light scattering coefficient (σsp); calculated parameters include absorption Ångström exponent (AAE), and single scattering albedo (ωo). The light absorption and scattering coefficients were found to be low in the winter and highest in the spring and summer. Spring-summer means of σap and σsp were 0.15 ± 0.15 Mm-1 and 2.35 ± 2.80 Mm-1, respectively. Mean AAE was 0.97 ± 0.29 in the spring and summer, indicating that black carbon (BC), and not dust and/or organic brown carbon (BrC), is the main aerosol light absorber. Mean ωo was 0.93 ± 0.03, which is similar to values measured at Barrow, Alaska, USA (0.94 ± 0.05) and Ny-Ålesund, Svalbard, Norway (0.95 ± 0.06). Summit exhibits ωo as low as Barrow and Ny-Ålesund although it is an isolated high-altitude site indicating the importance of aerosol light absorption over the most remote Arctic locations.
3

Fabrication of crystals from single metal atoms

Barry, Nicolas P.E., Pitto-Barry, Anaïs, Sanchez, A.M., Dove, A.P., Procter, R.J., Soldevila-Barreda, Joan J., Kirby, N., Hands-Portman, I., Smith, C.J., O'Reilly, R.K., Beanland, R., Sadler, P.J. 27 May 2014 (has links)
Yes / Metal nanocrystals offer new concepts for the design of nanodevices with a range of potential applications. Currently the formation of metal nanocrystals cannot be controlled at the level of individual atoms. Here we describe a new general method for the fabrication of multi-heteroatom-doped graphitic matrices decorated with very small, ångström-sized, three-dimensional (3D)-metal crystals of defined size. We irradiate boron-rich precious-metal-encapsulated self-spreading polymer micelles with electrons and produce, in real time, a doped graphitic support on which individual osmium atoms hop and migrate to form 3D-nanocrystals, as small as 15 Å in diameter, within 1 h. Crystal growth can be observed, quantified and controlled in real time. We also synthesize the first examples of mixed ruthenium–osmium 3D-nanocrystals. This technology not only allows the production of ångström-sized homo- and hetero-crystals, but also provides new experimental insight into the dynamics of nanocrystals and pathways for their assembly from single atoms. / We thank the Leverhulme Trust (Early Career Fellowship No. ECF-2013-414 to NPEB), the University of Warwick (Grant No. RDF 2013-14 to NPEB), the Swiss National Science Foundation (Grant No. PA00P2_145308 to NPEB and PBNEP2_142949 to APB), the ERC (Grant No. 247450 to PJS), EPSRC (EP/G004897/1 to RKOR, and EP/F034210/1 to PJS) and Science City (AWM/ERDF) for support. We thank the Wellcome Trust (Grant No. 055663/Z/98/Z) for funding the Electron Microscopy Facility, School of Life Sciences, University of Warwick. We also thank COST Action CM1105 for stimulating discussions, Thomas Wilks for supplying the micelle image for Figure 1, and the Australian Synchrotron and the University of Monash for allocation of time on the SAXS/ WAXS beamline and funding. The 2000FX Gatan Orius digital TEM camera used in this research was funded by Science City: Creating and Characterizing Next Generation Advanced Materials, with support from Advantage West Midlands and part funded by the European Regional Development Fund.
4

Kommunikation i byggprojektering : En studie över användandet av agila ärendehanteringsverktyg inom byggprojektering / Communication within construction planning

Roland Sandblad, Maria, Nilsson, Johannes January 2018 (has links)
Byggbranschen är en konservativ bransch som länge har setts som motsträvig och traditionell. Detta har resulterat i en långsam utveckling av kommunikationsmönster och former för ledning och samverkan i branschen. En god kommunikation är en förutsättning för lyckade byggprojekt, varför det är av stort intresse att säkerställa en sådan. Denna rapport undersöker hur projekteringsbranschens kommunikation ser ut i dag och hur denna kan förbättras med hjälp av nätverksbaserade agila projektlednings- och kommunikationssystem. Den utreder även hur de i dag tillgängliga systemen anses fungera och dessa kan utveckla kommunikationen inom byggprojektering. Detta görs genom att studera hur användare av det agila projektlednings- och kommunikationssystemet Jira upplever att det fungerar och används. För att undersöka detta användes en kvalitativ metod i form av intervjuer med projektledare, BIM-samordnare och konsulter vid projekten. Denna intervjustudie kompletterades med en kvantitativ undersökning med ett internetbaserat formulär. Båda dessa studier är baserade på en inledande litteraturstudie. Genom att jämföra och analysera de två studierna har slutsatser dragits kring dagens och framtidens kommunikation. De visar att det finns en positiv inställning hos respondenterna till att använda nätverksbaserade kommunikationssystem hos respondenterna. Man kan se att kommunikationen inom byggprojektering kan förbättras och effektiviseras med hjälp av den typ av nätverksbaserade kommunikationssystem som behandlas i rapporten. Baserat på dessa resultat samt tidigare forskning kan man dra slutsatsen att detta nya kommunikationssätt kan leda till en sänkning av både kostnad och tidsåtgång vid byggprojekt. Utöver dessa frågeställningar och slutsatser har studien resulterat i ett antal rekommendationer för det företag som arbetet har skrivits för, Plan B AB. Dessa rekommendationer bildar ett underlag för en ytterligare utveckling av den Jira som används i deras nuvarande projekt vid Ångströmlaboratoriet. / The construction industry is a conservative industry that has for a long time been seen as recalcitrant and traditional, which has resulted in a slow development in business communication systems. This report covers how communication in project planning looks like today. The report also sheds light on opinions this branch of industry has of agile project leading- and communication systems. The study that was performed provided information on how the users view Jira, the agile project leading and communication system, and how it operates. To examine this a qualitative investigation was done in the form of interviews with project leaders, coordinators and consultants. To achieve a somewhat wider response group a survey was conducted through an Internet based questionnaire. The purpose of the study was to identify how coworkers in a Jirabased project feel about the program’s usefulness, if it helps or hinders productivity, if there are any possible features that need improving, and what the users think about the work environment of Jira. The result of the study was a positive opinion of both Jira as a software program and the overall change in project communication opportunities. The study also provided ideas on how to adapt Jira to the project planning branch of the construction industry. In addition, the study also resulted in suggestions on how the company can improve their usage of Jira in the case study for the thesis.
5

Long-Term Variation Study of Fine-Mode Particle Size and Regional Characteristics Using AERONET Data

Shin, Juseon, Sim, Juhyeon, Dehkhoda, Naghmeh, Joo, Sohee, Kim, Taegyeong, Kim, Gahyeong, Müller, Detlef, Tesche, Matthias, Shin, Sung-Kyun, Shin, Dongho, Noh, Youngmin 11 March 2024 (has links)
To identify the long-term trend of particle size variation, we analyzed aerosol optical depth (AOD, τ) separated as dust (τD) and coarse-(τPC) and fine-pollution particles (τPF) depending on emission sources and size. Ångström exponent values are also identified separately as total and fine-mode particles (αT and αPF). We checked these trends in various ways; (1) first-order linear regression analysis of the annual average values, (2) percent variation using the slope of linear regression method, and (3) a reliability analysis using the Mann–Kendall (MK) test. We selected 17 AERONET sun/sky radiometer sites classified into six regions, i.e., Europe, North Africa, the Middle East, India, Southeast Asia, and Northeast Asia. Although there were regional differences, τ decreased in Europe and Asian regions and increased in the Middle East, India, and North Africa. Values of τPC and τPF, show that aerosol loading caused by non-dust aerosols decreased in Europe and Asia and increased in India. In particular, τPF considerably decreased in Europe and Northeast Asia (95% confidential levels in MK-test), and τPC decreased in Northeast Asia (Z-values for Seoul and Osaka are −2.955 and −2.306, respectively, statistically significant if |z| ≥ 1.96). The decrease in τPC seems to be because of the reduction of primary and anthropogenic emissions from regulation by air quality policies. The meaningful result in this paper is that the particle size became smaller, as seen by values of αT that decreased by −3.30 to −30.47% in Europe, North Africa, and the Middle East because αT provides information on the particle size. Particle size on average became smaller over India and Asian regions considered in our study due to the decrease in coarse particles. In particular, an increase of αPF in most areas shows the probability that the average particle size of fine-mode aerosols became smaller in recent years. We presumed the cause of the increase in αT is because relatively large-sized fine-mode particles were eliminated due to air quality policies.

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