224 research outputs found
Radiation-cooled Dew Water Condensers Studied by Computational Fluid Dynamic (CFD)
Harvesting condensed atmospheric vapour as dew water can be an alternative or
complementary potable water resource in specific arid or insular areas. Such
radiation-cooled condensing devices use already existing flat surfaces (roofs)
or innovative structures with more complex shapes to enhance the dew yield. The
Computational Fluid Dynamic - CFD - software PHOENICS has been programmed and
applied to such radiation cooled condensers. For this purpose, the sky
radiation is previously integrated and averaged for each structure. The
radiative balance is then included in the CFD simulation tool to compare the
efficiency of the different structures under various meteorological parameters,
for complex or simple shapes and at various scales. It has been used to precise
different structures before construction. (1) a 7.32 m^2 funnel shape was
studied; a 30 degree tilted angle (60 degree cone half-angle) was computed to
be the best compromise for funnel cooling. Compared to a 1 m^2 flat condenser,
the cooling efficiency was expected to be improved by 40%. Seventeen months
measurements in outdoor tests presented a 138 % increased dew yield as compared
to the 1 m^2 flat condenser. (2) The simulation results for 5 various condenser
shapes were also compared with experimental measurement on corresponding pilots
systems: 0.16 m^2 flat planar condenser, 1 m^2 and 30 degree tilted planar
condenser, 30 m^2 and 30 degree tilted planar condenser, 255 m^2 multi ridges,
a preliminary construction of a large scale dew plant being implemented in the
Kutch area (Gujarat, India)
Fog and Dew Collection Projects in Croatia
The present paper discusses the fog and dew water collection in Croatia.
Zavizan, the highest meteorological station in Croatia(1594m) is chosen for
collecting of fog water with a standard fog collector (SFC). The highest daily
collection rate was 27.8 L / m2. The highest daily collection rate in days
without rain was 19.1 l/m2. Dew is also a noticeable source of water,
especially during the drier summer season. Dew condensers in Croatia have been
installed on the Adriatic coast (Zadar) and islands Vis and Bisevo. We report
and discuss the data collected since 2003. In the small Bisevo island, a
special roof has been designed to improve the formation and collection of dew
on a house. Data from April 2005 will be presented and discussed.Comment: accessible sur
http://balwois.mpl.ird.fr/balwois/administration/full_paper/ffp-587.pd
Fog and Dew as Potable Water Resources: Maximizing Harvesting Potential and Water Quality Concerns
Fog and dew are often viewed as economic nuisances causing significant financial losses in the transportation industry and agricultural sector. However, they are also critical components of the hydrological cycle, especially in water scarce environments. Water scarcity is one of the major threats to mankind in the 21st century, and this can be due to development pressures, pollution, and/or expanding populations. In water scarce environments, fog and dew represent potentially exploitable ancillary water resources that could ameliorate the water scarce situation, if efficiently harvested. However, two important issues are often overlooked in relation to fog and dew harvesting and potability. First, current fog and dew harvesting technologies are low yielding with great potential for improvements. Second and more importantly, the potability of these water resources is often based on simple analyses that often omit trace metal and biological analyses. The few studies that report trace metal or biological measurements suggest elevated trace metal concentrations or biological contamination that could be of concern to public health. We discuss the potential for fog and dew harvesting technologies and the need for trace metal and biological analyses of these waters before use
Set optimization - a rather short introduction
Recent developments in set optimization are surveyed and extended including
various set relations as well as fundamental constructions of a convex analysis
for set- and vector-valued functions, and duality for set optimization
problems. Extensive sections with bibliographical comments summarize the state
of the art. Applications to vector optimization and financial risk measures are
discussed along with algorithmic approaches to set optimization problems
Levantamento de reconhecimento de alta intensidade dos solos das bacias hidrogrĂĄficas dos rios Guapi-Macacu e Caceribu.
O presente estudo refere-se ao levantamento dos solos da bacia hidrogrĂĄfica dos rios Guapi-Macacu e Caceribu, Estado do Rio de Janeiro, que abrange uma ĂĄrea aproximada de 2.072 km2, realizado em nĂvel de reconhecimento de alta intensidade de acordo com as normas preconizadas pela Embrapa Solos, com a utilização de geotecnologias e tĂ©cnicas de mapeamento digital. Consiste na caracterização dos solos visando contribuir para o planejamento do uso e ocupação das terras de forma racional e sustentĂĄvel. Como material bĂĄsico, utilizou-se cartas topogrĂĄfica do IBGE na escala de 1:50.000, que foram empregadas para geração de um modelo digital de elevação (MDE), tendo ainda o apoio de imagens do sensor TM do satĂ©lite Landsat 5 de 2011 e imagens Alos de 2007. Os resultados apresentados neste relatĂłrio tĂ©cnico, alĂ©m de permitir uma visĂŁo geral sobre as principais caracterĂsticas ambientais da ĂĄrea, contĂ©m todos os critĂ©rios utilizados para distinção e classificação dos solos e uma descrição das principais classes de solos da bacia estudada, cuja distribuição espacial Ă© representada em um mapa na escala 1:50.000. Este mapa Ă© constituĂdo por 51 unidades de mapeamento, que compĂ”em uma legenda de identificação dos solos, individualizados atĂ© o quinto nĂvel categĂłrico, seguido das fases de vegetação, relevo e, para solos pouco evoluĂdos, substrato geolĂłgico. As principais classes de solos identificadas foram: Argissolos Amarelos, Argissolos Vermelho e Argissolos Vermelho- Amarelos; Latossolos Amarelos, Latossolos Vermelhos e Latossolos Vermelho-Amarelos; Cambissolos HĂĄplicos, Neossolos LitĂłlicos e Neossolos RegolĂticos; Luvissolos CrĂŽmicos; e Nitossolos HĂĄplicos, que predominam nas ĂĄreas de relevo degradacionais, enquanto nas ĂĄreas de relevo de agradação (baixadas) ocorrem os Gleissolos TiomĂłrficos, Gleissolos SĂĄlicos, Gleissolos MelĂąnicos e Gleissolos HĂĄplicos; Neossolos FlĂșvicos; Planossolos HĂĄplicos; e Organossolos.bitstream/item/160857/1/BPD-257-Levantamento-Reconh-BH-Guapi-Macacu.pd
Measurement of the inclusive and fiducial tt ÂŻ production cross-sections in the lepton+jets channel in pp collisions at s â =8 TeV with the ATLAS detector
The inclusive and fiducial tt ÂŻ production cross-sections are measured in the lepton+jets channel using 20.2 fb â1 of proton-proton collision data at a centre-of-mass energy of 8 TeV recorded with the ATLAS detector at the LHC. Major systematic uncertainties due to the modelling of the jet energy scale and b -tagging efficiency are constrained by separating selected events into three disjoint regions. In order to reduce systematic uncertainties in the most important background, the W+jets process is modelled using Z+jets events in a data-driven approach. The inclusive tt ÂŻ cross-section is measured with a precision of 5.7% to be Ï inc (tt ÂŻ ) = 248.3 ± 0.7 (stat.) ± 13.4 (syst.) ± 4.7 (lumi.) pb, assuming a top-quark mass of 172.5 GeV. The result is in agreement with the Standard Model prediction. The cross-section is also measured in a phase space close to that of the selected data. The fiducial cross-section is Ï fid (tt ÂŻ ) = 48.8 ± 0.1 (stat.) ± 2.0 (syst.) ± 0.9 (lumi.) pb with a precision of 4.5%
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