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Assessment of the structure and variability ofWeddell Sea water masses in distinct ocean reanalysis products

Dotto, T S; Kerr, R; Mata, M M; Azaneu, M; Wainer, Ilana Elazari Klein Coaracy; Fahrbach, E; Rohardt, G
Fonte: Biblioteca Digital da Produção Intelectual da USP Publicador: Biblioteca Digital da Produção Intelectual da USP
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.32%
We assessed and evaluated the performance of five ocean reanalysis products in reproducing essential hydrographic properties and their associated temporal variability for the Weddell Sea, Antarctica. The products used in this assessment were ECMWF ORAS4 (European Centre for Medium-Range Weather Forecasts Ocean Reanalysis System 4), CFSR (Climate Forecast System Reanalysis), My- Ocean UR025.4 (University of Reading), ECCO2 (Estimating the Circulation and Climate of the Ocean, Phase II) and SODA (Simple Ocean Data Assimilation). The present study focuses on the Weddell Sea deep layer, which is composed of the following three main water masses: Warm Deep Water (WDW),Weddell Sea DeepWater (WSDW) andWeddell Sea Bottom Water (WSBW). The MyOcean UR025.4 product provided the most accurate representation of the structure and thermohaline properties of theWeddell Sea water masses when compared with observations. All the ocean reanalysis products analyzed exhibited limited capabilities in representing the surface water masses in the Weddell Sea. The CFSR and ECCO2 products were not able to represent deep water masses with a neutral density_28.40 kgm−3, which was considered the WSBW’s upper limit throughout the simulation period. The expected WDW warming was only reproduced by the SODA product...

Investigação numérica das massas de água do Mar de Ross usando o Regional Ocean Modeling System - ROMS; Numerical Investigation of the Ross Sea water masses using the Regional Ocean Modeling System - ROMS

Tonelli, Marcos Henrique Maruch
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 14/04/2014 PT
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56.26%
A formação de águas profundas na Antártica afeta diretamente o clima global, uma vez que este processo conecta os ramos superior e inferior da circulação termohalina global (MOC). Avaliar os impactos das mudanças climáticas nestes processos é importante para compreensão do transporte global de calor pelos oceanos e para realização de projeções climáticas. Aplicando a forçante interanual Coordinated Ocean-Ice Reference (CORE), foi realizada uma simulação de 60 anos (1948-2007) utilizando o ROMS com módulos de gelo marinho e plataforma de gelo ativos. Uma rodada preliminar de 100 anos foi realizada com forçante do ano normal CORE, para gerar campos estáveis de inicialização da rodada interanual. Para ambos os experimentos adotou-se uma grade circumpolar periódica com resolução variável, alcançando cerca de 5 km na borda sul. Para investigar as massas de água foi aplicada a Análise Multiparamétrica Ótima - OMP. As principais massas de água do Mar de Ross foram identificadas: Água de Superfície Antártica (AASW), Água Circumpolar Profunda (CDW), Água de Fundo Antártica (AABW) e Água de Plataforma (SW), posteriormente separadas em Água da Plataforma de Gelo (ISW) e Água de Plataforma de Alta Salinidade (HSSW). Os resultados são consistentes com observações prévias (Bergamasco...

Influence of sea water resistivity on MCSEM data

Luz,Edelson da Cruz; Régis,Cícero Roberto Teixeira
Fonte: Sociedade Brasileira de Geofísica Publicador: Sociedade Brasileira de Geofísica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2009 EN
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56.06%
The Marine Controlled Source ElectroMagnetic (MCSEM) method is a geophysical tool for the detection of resistive targets in the subsurface of the oceanic floor. In this work we model MCSEM data in one-dimensional environments, including variations in the resistivity of the ocean water, as horizontal layers of uniform resistivity. Such variations can arise from the influence of marine currents, temperature gradients or any other source of influence on the water salinity.We study the effect of such variations on the MCSEM data. Our results show that the interpretation can be strongly influenced, especially for normalized data. We see that changes in the water resistivity have a similar effect on the data as changes in the water depth, and that both affect the attenuation of the so called "air-wave".

Optimization of experimental parameters in the determination of zinc in sea water by adsorptive stripping voltammetry

Arancibia,V.; Zúñiga,M.; Zúñiga,M. C.; Segura,R.; Esteban,M.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2010 EN
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66.25%
A procedure for the determination of zinc in sea water by square wave adsorptive stripping voltammetry (SWAdSV) using 8-hydroxyquinoline (oxine) as an adsorbing and complexing agent has been optimized. First, a univariate study of the Zn-Ox complex peak current as a function of pH was carried out choosing values at which adequate currents were obtained. Then, selection of the experimental conditions was made using a multivariate experimental design. Variables like pH, oxine concentration (Cox), adsorption time (t ads) and adsorption potential (Eads) were optimized. The first optimization step was a 2(4) factorial design with 16 measurements made choosing high and low levels, and three measurements at the central point (Zn(II) 10.0 μg L-1). Analysis of variance showed that pH and Cox were the most significant factors, while t ads and Eads were not significant and were kept constant in later measurements. Next, to find the optimum values for pH and Cox a 2² + star factorial design was used. The best experimental parameters were pH = 6.0; Cox = 25 μmol L-1; t ads = 10 s and Eads = -0.70 V. Under these conditions the peak current was proportional to the concentration of zinc over the 0.1-48.0 μg L-1 range, with a detection limit of 0.05 μg L-1. Reproducibility for 5.0 μg mL-1 Zn(II) solution was 1.9 % (n = 16). The method was validated using spiked synthetic sea water (ASTM D665)...

Production of bioemulsifiers by Yarrowia lipolytica in sea water using diesel oil as the carbon source

Souza,F. A. S. D.; Salgueiro,A. A.; Albuquerque,C. D. C.
Fonte: Brazilian Society of Chemical Engineering Publicador: Brazilian Society of Chemical Engineering
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2012 EN
Relevância na Pesquisa
66.06%
The objective of this work was to investigate, on a flask scale, the production of bioemulsifiers by Yarrowia lipolytica in the presence of sea water, supplemented with nitrogen and phosphate sources, using diesel oil as substrate. A full 2(4) factorial design was conducted to investigate the effects and interactions of the nutrient concentrations (diesel oil, urea, ammonium sulfate and monobasic potassium phosphate) on the response variables: emulsification activity and surface tension of the cell-free cultures. High emulsification activities (> 5,4 UEA) were determined after 168 h in all the experiments. The interactions among diesel oil, urea and monobasic potassium phosphate favored the emulsification with statistical significance. A correlation between the increase of emulsification activity and the reduction of surface tension was not identified.

Yeasts isolated from sand and sea water in beaches of Olinda, Pernambuco state, Brazil

Loureiro,Silvia Tereza Azedo; Cavalcanti,Maria Auxiliadora de Queiroz; Neves,Rejane Pereira; Passavante,José Zanon de Oliveira
Fonte: Sociedade Brasileira de Microbiologia Publicador: Sociedade Brasileira de Microbiologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2005 EN
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56.02%
The aim of this work was to isolate and identify yeasts from sand and sea water collected in two beaches of Olinda, Pernambuco state, Brazil. Thirty two samples of both sand and water in both beaches were obtained in the dry (December 2000 and February 2001) and rainy (June and July 2001) seasons. Two hundred and ninety two strains of yeast were obtained, and they belonged to four genera and 31 species. Candida was the most prevalent genus. Candida catenulata, C. fenica, C. sake, Brettanomyces bruxelenses and Rhodotorula mucilaginosa were the most commonly found species in both beaches Bairro Novo and Casa Caiada.

Evaluation of Factors Affecting Survival of Escherichia coli in Sea Water: V. Studies with Heat- and Filter-sterilized Sea Water1

Carlucci, A. F.; Scarpino, P. V.; Pramer, David
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /09/1961 EN
Relevância na Pesquisa
46.28%
The bactericidal action of sea water was measured as the difference in survival of cells of Escherichia coli in untreated and autoclaved portions of water samples. The beneficial effect of sterilization by heat on the survival of E. coli in sea water varied with season and was most marked during summer months, however, the magnitude of the effect differed greatly from sample to sample. The more obvious and commonly suggested explanations for the bactericidal action of sea water were tested experimentally. The pH and salinity of sea water were changed by autoclaving, but the direction of the former was detrimental rather than beneficial and the significance of the latter was not clarified. The survival of cells of E. coli in filtered portions of some water samples was greater than that in untreated portions and equal to that in autoclaved portions, indicating that predators and competitors removed by filtration had contributed significantly to the rapid death of the bacterium in the untreated water. However, in the majority of samples tested, survival of E. coli in autoclaved water was considerably greater than survival in filtered water.

THE CONCENTRATION EFFECT WITH VALONIA: POTENTIAL DIFFERENCES WITH CONCENTRATED AND DILUTED SEA WATER

Damon, E. B.; Osterhout, W. J. V.
Fonte: The Rockefeller University Press Publicador: The Rockefeller University Press
Tipo: Artigo de Revista Científica
Publicado em 20/03/1930 EN
Relevância na Pesquisa
46.34%
The P.D. between the interior of a cell of Valonia macrophysa and concentrated or diluted sea water applied externally is given by the empirical equation: See PDF for Equation where P.D.s.w. is the value observed when the external solution is sea water. The sign is that of the interior of the cell. In the chain: sea water, concn.1 | Valonia | sea water, concn.2 therefore, the more concentrated solution is positive in the external circuit to the more dilute solution. This holds for the concentration range 1.5 sea water to 0.2 sea water, when the dilute solutions are made isotonic with sea water by the addition of a suitable non-electrolyte (such as glycerol). Prolonged exposure to these solutions, or brief exposure to very concentrated or very dilute sea water, or to hypotonic solutions, produces in the cell secondary changes which are made evident by the reversal of the sign of the P.D. These changes are to a certain extent reversible, but if allowed to proceed too far they become irreversible, involving permanent injury to the cell. The concentration effect with sea water is shown to be practically the concentration effect for NaCl, the part played by the other salts in sea water being relatively small.

STIMULATION OF FUNDULUS BY HYDROCHLORIC AND FATTY ACIDS IN FRESH WATER, AND BY FATTY ACIDS, MINERAL ACIDS, AND THE SODIUM SALTS OF MINERAL ACIDS IN SEA WATER

Allison, J. B.; Cole, William H.
Fonte: The Rockefeller University Press Publicador: The Rockefeller University Press
Tipo: Artigo de Revista Científica
Publicado em 20/07/1934 EN
Relevância na Pesquisa
46.34%
1. Fundulus heteroclitus was found to be a reliable experimental animal for studies on chemical stimulation in either fresh or sea water. 2. The response of Fundulus to hydrochloric, acetic, propionic, butyric, valeric, and caproic acids was determined in fresh water, while the same acids plus sulfuric and nitric, as well as the sodium salts of the mineral acids, were tested in sea water. 3. Stimulation of Fundulus by hydrochloric acid in fresh water is correlated with the effective hydrogen ion concentration. Stimulation by the n-aliphatic acids in the same environment is correlated with two factors, the effective hydrogen ion concentration and the potential of the non-polar group in the molecule. However, as the number of CH2 groups increases the stimulating effect increases by smaller and smaller amounts, approaching a maximum value. 4. Stimulation of Fundulus by hydrochloric, sulfuric, and nitric acids in sea water is correlated with the forces of primary valence which in turn are correlated with the change in hydrogen ion concentration of the sea water. The n-aliphatic acids increase in stimulating efficiency in sea water as the length of the carbon chain increases, but a limiting value is not reached as soon as in fresh water. 5. Only a slight difference in stimulation by hydrochloric acid is found in sea water and in fresh water. However...

THE COMPOSITION OF FLUIDS AND SERA OF SOME MARINE ANIMALS AND OF THE SEA WATER IN WHICH THEY LIVE

Cole, William H.
Fonte: The Rockefeller University Press Publicador: The Rockefeller University Press
Tipo: Artigo de Revista Científica
Publicado em 20/05/1940 EN
Relevância na Pesquisa
46.28%
1. The electrolyte composition, the pH, and freezing points of the fluids of several invertebrates and one primitive chordate are reported. 2. Fluids of the worms, echinoderms, and the clam Venus were isotonic with sea water; fluids of the Arthropoda were hypertonic to sea water. 3. The pH of all fluids was below that of sea water. In the Arthropoda and Myxine less individual variation in pH appeared than in the echinoderms and worms. 4. Ratios of ionic concentrations in the fluid to those in the sea water indicated (1) uniform distribution of ions between the internal and external media for the echinoderms and Venus, (2) differential distribution of potassium and magnesium in the worms; (3) differential distribution of sulfate, magnesium, potassium, and calcium in the Arthropoda; and (4) differential distribution of calcium, magnesium, and sulfate in Myxine. 5. The unequal distribution of ions implies the expenditure of energy against a concentration gradient across the absorbing or excreting membranes, a capacity frequently overlooked in the invertebrates. 6. The sera of the Arthropoda from diluted sea water showed higher concentrations of sodium, potassium, calcium, and chloride ions relative to the respective concentrations in the external medium than in normal sea water...

Modeling Caspian Sea water level oscillations under different scenarios of increasing atmospheric carbon dioxide concentrations

Roshan, GholamReza; Moghbel, Masumeh; Grab, Stefan
Fonte: BioMed Central Publicador: BioMed Central
Tipo: Artigo de Revista Científica
Publicado em 12/12/2012 EN
Relevância na Pesquisa
46.29%
The rapid rise of Caspian Sea water level (about 2.25 meters since 1978) has caused much concern to all five surrounding countries, primarily because flooding has destroyed or damaged buildings and other engineering structures, roads, beaches and farm lands in the coastal zone. Given that climate, and more specifically climate change, is a primary factor influencing oscillations in Caspian Sea water levels, the effect of different climate change scenarios on future Caspian Sea levels was simulated. Variations in environmental parameters such as temperature, precipitation, evaporation, atmospheric carbon dioxide and water level oscillations of the Caspian sea and surrounding regions, are considered for both past (1951-2006) and future (2025-2100) time frames. The output of the UKHADGEM general circulation model and five alternative scenarios including A1CAI, BIASF, BIMES WRE450 and WRE750 were extracted using the MAGICC SCENGEN Model software (version 5.3). The results suggest that the mean temperature of the Caspian Sea region (Bandar-E-Anzali monitoring site) has increased by ca. 0.17°C per decade under the impacts of atmospheric carbon dioxide changes (r=0.21). The Caspian Sea water level has increased by ca. +36cm per decade (r=0.82) between the years 1951-2006. Mean results from all modeled scenarios indicate that the temperature will increase by ca. 3.64°C and precipitation will decrease by ca. 10% (182 mm) over the Caspian Sea...

Evolution of the Irminger Current anticyclones in the Labrador Sea from hydrographic data

Rykova, Tatiana
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 143 p.
ENG
Relevância na Pesquisa
46.28%
The continuous supply of heat and fresh water from the boundaries to the interior of the Labrador Sea plays an important role for the dynamics of the region and in particular, for the Labrador Sea Water formation. Thus, it is necessary to understand the factors governing the exchange of properties between the boundary and interior. A significant fraction of heat and fresh water, needed to balance the annual heat loss and to contribute to the seasonal freshening of the Labrador Sea, is thought to be provided by coherent long-lived anticyclonic eddies shed by the Irminger Current. The population, some properties, rates and direction of propagation of these anomalies are known but the evolution and the mechanism of their decay are still far from obvious. In this work I investigated their water mass properties and evolution under the strong wintertime forcing using hydrographic data from 1990-2004 and a 1-dimensional mixed layer model. There were 50 eddies found in the hydrographic data record, 48 of which were identified as anticyclones. Vertical structure of the eddies was investigated, leading to the categorization of all the anticyclones into three classes: 12 - with a fresh surface layer and no mixed layer, 18 - without a fresh layer and at least one mixed layer...

Strategic Environmental Assessment : Improving Water Resources Governance and Decision Making - Case Studies

Hirji, Rafik; Davis, Richard
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
EN_US
Relevância na Pesquisa
46.28%
The overall goal of this report is to help water resources and environment professionals within the Bank and client countries use strategic environmental assessment (SEA) to effectively implement the principles of integrated water resources management (IWRM). The report contains four elements: (1) a review of SEA support for IWRM; (2) an analysis of 10 case studies and four water policies; (3) an in-depth pilot study of water sector reform in a developing country; and (4) a framework for enhancing the use of SEAs in integrated water resources management. This SEA provides important lessons on the usage of SEA rather than on the technical aspects of conducting them. It illustrates how an environmental instrument can be used to further development and poverty alleviation as well as environmental protection by putting its findings and recommendations in terms that are meaningful to politicians and senior decision makers. This includes use of economic and financial arguments and linkages to national goals such as poverty reduction and millennium development goals (MDGs). It also illustrates the importance of building support among a wider constituency than just the lead agency and working patiently over a number of years to implement reforms. The influence of an SEA can be felt a number of years as opportunities arise to implement components of a reform program. Finally...

Fatigue crack initiation and growth on a steel in the very high cycle regime with sea water corrosion

PALIN-LUC, Thierry; PÉREZ-MORA, Ruben; BATHIAS, Claude; DOMINGUEZ, Gonzalo; PARIS, Paul C.; ARANA, Jose Luis
Fonte: Elsevier Publicador: Elsevier
EN
Relevância na Pesquisa
66.14%
The authors acknowledge Arts et Métiers ParisTech and Foundation Arts et Métiers for the financial support of P.C. Paris’ stay at LAMEFIP. They acknowledge Vicinay Cadenas S.A. for its financial support, and both the PCP France-Mexique and the CONACYT for their financial support too.; This paper is devoted to the effect of corrosion on the gigacycle fatigue strength of a martensitic–bainitic hot rolled steel used for manufacturing offshore mooring chains for petroleum platforms. Smooth specimens were tested under fully reversed tension between 1E6 and 1E10 cycles in three testing conditions and environments: (i) in air, (ii) in air after precorrosion and (iii) in air under real time artificial sea water flow. The fatigue strength at greater than 108 cycles is reduced by a factor more than five compared with non-corroded specimens. Fatigue cracks initiate at corrosion pits due to pre-corrosion, if any, or pits resulting from corrosion in real time during the cyclic loading. It is shown that under sea water flow, the fatigue life in the gigacycle regime is mainly governed by the corrosion process. Furthermore, the calculation of the mode I stress intensity factor at hemispherical surface defects (pits) combined with the Paris–Hertzberg–Mc Clintock crack growth rate model shows that fatigue crack initiation regime represents most of the fatigue life.; PCP France Mexique...

BIOELECTRIC POTENTIALS IN VALONIA : THE EFFECT OF SUBSTITUTING KCl FOR NaCl IN ARTIFICIAL SEA WATER

Damon, E. B.
Fonte: The Rockefeller University Press Publicador: The Rockefeller University Press
Tipo: Artigo de Revista Científica
Publicado em 20/11/1932 EN
Relevância na Pesquisa
46.34%
The P.D. across the protoplasm of Valonia macrophysa has been studied while the cells were exposed to artificial solutions resembling sea water in which the concentration of KCl was varied from 0 to 0.500 mol per liter. The P.D. across the protoplasm is decreased by lowering and increased by raising the concentration of KCl in the external solution. Changes in P.D. with time when the cell is treated with KCl-rich sea water resemble those observed with cells exposed to Valonia sap. Varying the reaction of natural sea water from pH 5 to pH 10 has no appreciable effect on the P.D. across Valonia protoplasm. Similarly, varying the pH of KCl-rich sea water within these limits does not alter the height of the first maximum in the P.D.-time curve. The subsequent behavior of the P.D., however, is considerably affected by the pH of the KCl-rich sea water. These changes in the shape of the P.D.-time curve have been interpreted as indicating that potassium enters Valonia protoplasm more rapidly from alkaline than from acidified KCl-rich sea water. This conclusion is discussed in relation to certain theories which have been proposed to explain the accumulation of KCl in Valonia sap. The initial rise in P.D. when a Valonia cell is transferred from natural sea water to KCl-rich sea water has been correlated with the concentrations of KCl in the sea waters. It is assumed that the observed P.D. change represents a diffusion potential in the external surface layer of the protoplasm...

Estimation of the Adriatic sea water turnover time using fallout 90Sr as a radioactive tracer

Franic, Z.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 25/10/2004
Relevância na Pesquisa
46.32%
Systematic, long term measurements, starting in 1963, of 90Sr activity concentrations in sea water have been performed at four locations (cities of Rovinj, Rijeka, Split and Dubrovnik) along the Croatian coast of the Adriatic sea. In addition, fallout samples were collected in the city of Zadar. 90Sr activity concentrations are in good correlation with the fallout activity, the coefficient of correlation being 0.72. After the nuclear moratorium on atmospheric nuclear bomb tests in 1960s, 90Sr activity concentrations in sea water exponentially dropped from 14.8 +/- 2.4 Bq/m3 in 1963 to 2.0 +/- 0.3 Bq/m3 in 2003. In the same period, the total annual 90Sr land surface deposit in Zadar fell by three orders of magnitude, from 713.3 Bq/m2 in 1963 to 0.4 Bq/m2 in 2003. Using strontium sea water and fallout data, a mathematical model was developed to describe the rate of change of 90Sr activity concentrations in the Adriatic sea water and estimate its mean residence time in the Adriatic. By fitting the experimental data to a theoretically predicted curve, the mean residence time of 90Sr in the Adriatic sea water was estimated to be approximately 3.4 +/- 0.4 years, standard deviation being calculated by Monte Carlo simulations. As in physical oceanography 90Sr can be used as effective radioactive tracer of water mass transport...

Exploring integrated kinetic energy of polar mesoscale storms to estimate sea ice formation and salt fluxes in the Weddell Sea

Bernstein, Elizabeth Rachel
Fonte: University of Delaware Publicador: University of Delaware
Tipo: Tese de Doutorado
Relevância na Pesquisa
46.34%
Geiger, Cathleen A.; This dissertation examines the relationship between polar cyclones and sea ice cover. Through this research, an archive of polar cyclones is created. The archive contains storms for the time period 01 January 1979 through 31 August 2014 for the Weddell Sea, a region east of the Antarctic Peninsula extending to where the Southern Ocean and Indian Ocean meet. The four defined properties of polar cyclones used in this work are: high wind speeds, low pressures, short duration, and small spatial scales. The storm strength is expressed specifically through the maximum wind speed and minimum sea level pressure. The archive additionally includes characteristics of individual storms including the storm date, duration, strength, and size which are analyzed and compared to changes in sea ice cover during each storm. Subsequently, this research quantifies linkages between polar cyclones and sea ice by computing each storm's integrated kinetic energy as a measure of the size, duration, and wind speeds. Specific linkages include the surface energy balance, sea ice growth rate, and the quantity of brine rejected to the top of the water column. The results show that the area of open water is the biggest contributor to sea ice growth and brine production through new ice formation. The ejected brine from the ice increases the density of sea water in the nearby upper ocean layers which contribute to the destabilization of the water column. Subsequently...

Certified Reference Material for Radionuclides in Seawater IAEA-381 (Irish Sea Water)

Povinec, P; Badie, C; Baeza, A; Barci-Funel, G; Bergan, T D; Bojanowski, R.; Burnett, W; Eikenberg, J; Fifield, L Keith; Serradell, V.; Gastaud, J.; Goroncy, I.; Herrmann, J.; Hotchkis, Michael A; Ikaheimonen, T K; Jakobson, E.; Kalimbadjan, J.; La Rosa,
Fonte: Akademiai Kiado Publicador: Akademiai Kiado
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
66.1%
A certified reference material (CRM) for radionuclides in seawater, IAEA-381 (Irish Sea Water), is described and the results of certification are presented. The material has been certified for nine radionuclides (40K, 90Sr, 137Cs, 237Np, 238Pu, 239Pu, 240Pu, 239.240Pu and 241Am). Information on massic activities with the corresponding 95% confidence intervals are given for eight radionuclides (3H, 125Sb, 234U, 235U, 236U, 238U, 241Pu and 244Cm). Less reported radionuclides include 60Co, 99Tc, and 242Pu. The CRM may be used for quality assurance/quality control of the analysis of radionuclides in environmental water samples, for the development and validation of analytical methods and for training purposes. The material is available from the IAEA in 5 kg units.

The Effect of Eclipta Alba Leaves Extract on the Corrosion Inhibition Process of Carbon Steel in Sea Water

Johnsirani,V.; Sathiyabama,J.; Rajendran,S.; Christyc,S.M. Lydia; Jeyasundari,J.
Fonte: Sociedade Portuguesa de Electroquímica Publicador: Sociedade Portuguesa de Electroquímica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2013 EN
Relevância na Pesquisa
66.14%
The inhibition efficiency [IE] of an aqueous extract of eclipta alba leaves in controlling corrosion of carbon steel in sea water [Thondi, Tamil Nadu, India] has been evaluated by weight loss method. The weight loss study reveals that the formulation consisting of 6 mL of EAE (Eclipta Alba extract) and 25 ppm of Zn2+ has 92% inhibition efficiency in controlling corrosion of carbon steel in sea water. Polarization study reveals that EAE and Zn2+ system functions as a mixed type inhibitor. AC impedance spectra reveal that a protective film is formed on the metal surface. The nature of the metal surface has been analysed by FTIR spectra and AFM analysis.

Water services with independent providers in peri-urban Maputo: Challenges and opportunities for long-term development

Matsinhe,Nelson P; Juízo,Dinis; Rietveld,LC; Persson,Kenneth M
Fonte: Water SA Publicador: Water SA
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2008 EN
Relevância na Pesquisa
56.1%
Water service delivery to most residents of peri-urban areas of greater Maputo depends largely on alternative service providers, mostly in the form of small-scale independent providers (SSIPs). This paper discusses the present and long-term challenges facing SSIPs in supplying quality water of sufficient quantity in peri-urban Maputo and possible human health risks associated with the consumption of water provided by SSIPs. Extensive water sampling and analyses were conducted to evaluate the physicochemical and bacteriological quality of water provided by independent providers and the associated human health risks. Borehole pumping tests, the results of which were interpreted using the graphical method of Jacob, were used to evaluate the regional aquifer potential, the long-term impacts of its exploitation and the aquifer vulnerability to external contamination. From the results of borehole pumping tests it was concluded that the present yields are in average 33% lower than estimated safe yields and that larger than present yields therefore can be exploited. The aquifer vulnerability to external contamination (e.g. by E. coli and nitrates) is low, mainly because of low hydraulic loads and the existence of a rather thick (10 to 30 m) sandy unsaturated stratum where bacteria die-off and biological denitrification probably occurs. However...