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 hidrográficas dos rios Guapi-Macacu e Caceribu.

O presente estudo refere-se ao levantamento dos solos da bacia hidrográfica dos rios Guapi-Macacu e Caceribu, Estado do Rio de Janeiro, que abrange uma área aproximada de 2.072 km2, realizado em nível de reconhecimento de alta intensidade de acordo com as normas preconizadas pela Embrapa Solos, com a utilização de geotecnologias e técnicas de mapeamento digital. Consiste na caracterização dos solos visando contribuir para o planejamento do uso e ocupação das terras de forma racional e sustentável. Como material básico, utilizou-se cartas topográfica 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 satélite Landsat 5 de 2011 e imagens Alos de 2007. Os resultados apresentados neste relatório técnico, além de permitir uma visão geral sobre as principais características ambientais da área, contém todos os critérios utilizados para distinção e classificação dos solos e uma descrição das principais classes de solos da bacia estudada, cuja distribuição espacial é representada em um mapa na escala 1:50.000. Este mapa é constituído por 51 unidades de mapeamento, que compõem uma legenda de identificação dos solos, individualizados até o quinto nível categórico, seguido das fases de vegetação, relevo e, para solos pouco evoluídos, substrato geológico. As principais classes de solos identificadas foram: Argissolos Amarelos, Argissolos Vermelho e Argissolos Vermelho- Amarelos; Latossolos Amarelos, Latossolos Vermelhos e Latossolos Vermelho-Amarelos; Cambissolos Háplicos, Neossolos Litólicos e Neossolos Regolíticos; Luvissolos Crômicos; e Nitossolos Háplicos, que predominam nas áreas de relevo degradacionais, enquanto nas áreas de relevo de agradação (baixadas) ocorrem os Gleissolos Tiomórficos, Gleissolos Sálicos, Gleissolos Melânicos e Gleissolos Háplicos; Neossolos Flúvicos; Planossolos Háplicos; e Organossolos.bitstream/item/160857/1/BPD-257-Levantamento-Reconh-BH-Guapi-Macacu.pd

Measurement of the inclusive and fiducial tt ¯ production cross-sections in the lepton+jets channel in pp collisions at s √ =8 TeV with the ATLAS detector

The inclusive and fiducial tt ¯ production cross-sections are measured in the lepton+jets channel using 20.2 fb −1 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 ¯ cross-section is measured with a precision of 5.7% to be σ inc (tt ¯ ) = 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 σ fid (tt ¯ ) = 48.8 ± 0.1 (stat.) ± 2.0 (syst.) ± 0.9 (lumi.) pb with a precision of 4.5%