WorldWideScience

Sample records for natural seawater influence

  1. Corrosion of low alloy steels in natural seawater. Influence of alloying elements and bacteria

    International Nuclear Information System (INIS)

    Dajoux Malard, Emilie

    2006-01-01

    Metallic infrastructures immersed in natural seawater are exposed to important corrosion phenomena, sometimes characterised as microbiologically influenced corrosion. The presence of alloying elements in low alloy steels could present a corrosion resistance improvement of the structures. In this context, tests are performed with commercial steel grades, from 0,05 wt pc Cr to 11,5 wt pc Cr. They consist in 'on site' immersion in natural seawater on the one hand, and in laboratory tests with immersion in media enriched with marine sulphide-producing bacteria on the other hand. Gravimetric, microbiological, electrochemical measurements and corrosion product analyses are carried out and show that corrosion phenomenon is composed of several stages. A preliminary step is the reduction of the corrosion kinetics and is correlated with the presence of sessile sulphide-producing bacteria and an important formation of sulphur-containing species. This phase is shorter when the alloying element content of the steel increases. This phase is probably followed by an increase of corrosion, appearing clearly after an 8-month immersion in natural seawater for some of the grade steels. Chromium and molybdenum show at the same time a beneficial influence to generalised corrosion resistance and a toxic effect on sulphide-producing bacteria. This multidisciplinary study reflects the complexity of the interactions between bacteria and steels; sulphide-producing bacteria seem to be involved in corrosion processes in natural seawater and complementary studies would have to clarify occurring mechanisms. (author) [fr

  2. Nature/culture/seawater.

    Science.gov (United States)

    Helmreich, Stefan

    2011-01-01

    Seawater has occupied an ambiguous place in anthropological categories of "nature" and "culture." Seawater as nature appears as potentiality of form and uncontainable flux; it moves faster than culture - with culture frequently figured through land-based metaphors - even as culture seeks to channel water's (nature's) flow. Seawater as culture manifests as a medium of pleasure, sustenance, travel, disaster. I argue that, although seawater's qualities in early anthropology were portrayed impressionistically, today technical, scientific descriptions of water's form prevail. For example, processes of globalization - which may also be called "oceanization" - are often described as "currents," "flows," and "circulations." Examining sea-set ethnography, maritime anthropologies, and contemporary social theory, I propose that seawater has operated as a “theory machine” for generating insights about human cultural organization. I develop this argument with ethnography from the Sargasso Sea and in the Sea Islands. I conclude with a critique of appeals to water's form in social theory.

  3. Influence of bacteria and bacterial activity on the evolution of the free corrosion potentials of stainless steels in natural seawater

    International Nuclear Information System (INIS)

    Dupont, I.

    1996-10-01

    The free corrosion potential of a stainless steel under seawater increases. This increase depends of a lot of parameters, among them is found in particular: the temperature, the presence of molecular oxygen and the microorganisms. The aim of this work is to describe the role of the sea bacteria and of their activities on the increase of this potential. Stainless steel test-pieces have been put in natural seawater at different temperatures and their corrosion potential determined. It has been shown that the potential increases at 20 C but not at 40 C. The marine bacteria, present in seawater and fixed on the test-pieces at 20 and 40 C have been quantified by epi-fluorescence microscopy. The number of bacteria fixed at these two temperatures are similar. A sample of bacteria has been cut off on test-pieces and in seawater at 20 and 40 C. Their phenotypic analysis has allowed to classify them by numerical taxonomy in different phenons and by their metabolic spectra, it has been possible to distinguish the bacteria fixed at 20 C and those fixed at 40 C. The presence of an important bio-film at 40 C in the absence of a change of potential shows that the fixation of bacteria on stainless steel, if it is necessary, is not a sufficient condition for the starting of this phenomenon. The addition of a microbial enzyme in sterile seawater, the glucose oxidase, catalyzing the oxygen reduction in presence of glucose leads to an increase of the potential. The formation of hydrogen peroxide and the decrease of the pH of the medium seem responsible of this phenomenon. All these results have led us to propose a mechanism clarifying the increase of the potential of stainless steel in natural seawater. (O.M.)

  4. Behaviour of stainless steel in natural seawater

    OpenAIRE

    Compere, Chantal; Le Bozec, Nathalie

    1997-01-01

    In this paper, investigations performed in natural and artificial seawater on stainless steels will be presented. They concerned studies on: biofilm formation, passive layers composition, electrochemical behaviour, localised corrosion and the evolution of these different parameters as a function of ageing time. According to literature surveys, the different aspects will be discussed. Some conclusions will be drawn concerning the actual knowledge on the behaviour of stainless steels in seawater.

  5. Influence of non-smooth surface on tribological properties of glass fiber-epoxy resin composite sliding against stainless steel under natural seawater lubrication

    Science.gov (United States)

    Wu, Shaofeng; Gao, Dianrong; Liang, Yingna; Chen, Bo

    2015-11-01

    With the development of bionics, the bionic non-smooth surfaces are introduced to the field of tribology. Although non-smooth surface has been studied widely, the studies of non-smooth surface under the natural seawater lubrication are still very fewer, especially experimental research. The influences of smooth and non-smooth surface on the frictional properties of the glass fiber-epoxy resin composite (GF/EPR) coupled with stainless steel 316L are investigated under natural seawater lubrication in this paper. The tested non-smooth surfaces include the surfaces with semi-spherical pits, the conical pits, the cone-cylinder combined pits, the cylindrical pits and through holes. The friction and wear tests are performed using a ring-on-disc test rig under 60 N load and 1000 r/min rotational speed. The tests results show that GF/EPR with bionic non-smooth surface has quite lower friction coefficient and better wear resistance than GF/EPR with smooth surface without pits. The average friction coefficient of GF/EPR with semi-spherical pits is 0.088, which shows the largest reduction is approximately 63.18% of GF/EPR with smooth surface. In addition, the wear debris on the worn surfaces of GF/EPR are observed by a confocal scanning laser microscope. It is shown that the primary wear mechanism is the abrasive wear. The research results provide some design parameters for non-smooth surface, and the experiment results can serve as a beneficial supplement to non-smooth surface study.

  6. Colloidal nature of radionuclides in seawater

    International Nuclear Information System (INIS)

    Feldman, I.

    1976-01-01

    There is considerable doubt that equilibrium calculations, i.e., employing solubility products and complex-ion stability constants, are valid for the submicro concentrations of radionuclides in seawater. The existence of radiocolloids should be expected in seawater. The great tendency of radiocolloids to adsorb onto finely-divided hydrous oxides makes their formation of significance in seawater, especially for artificial radionuclides. The subject of radiocolloid formation is reviewed in this chapter. It is shown that the 226 Ra/ 230 Th/U relationship found in seawater can be explained from the fact that the tendencies of these elements to form radiocolloids in seawater should decrease in order thorium > radium much greater than uranium. This explanation is much simpler than the prevailing oceanographic one. The theories for radiocolloid formation are discussed. The recent theory of Jones and Healy for the adsorption of hydrolyzable metal ions onto hydrous oxides is reviewed briefly, and its relevance to radiocolloid formation is pointed out

  7. Greening Drylands with Seawater Easily and Naturally.

    Science.gov (United States)

    Moustafa, Khaled

    2017-03-01

    The sun and sea are inexhaustible sources of energy and water that could be used to transform drylands into more viable ecosystems. A sustainable and cost-effective approach is proposed for greening drylands and restoring wildlife and biodiversity in deserts using seawater desert-houses (or movable seawater ponds) that could offer important environmental advantages. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Study of the oxygen reduction reaction on stainless steel materials in natural seawater. Influence of the bio-film on corrosion processes

    International Nuclear Information System (INIS)

    Le Bozec, N.

    2000-01-01

    Bio-film development on stainless steels immersed in natural seawater can have prejudicial consequences on the resistance of these materials to corrosion. The goal of the present study was to get more precise information on the corrosion processes, and especially on the oxygen reduction reaction. As the reaction is linked to the stainless steel surface state, the characterisation of the oxides films (composition, structure, thickness...) is essential to understand the mechanisms and the oxygen reduction kinetic. The first aim of the study has been to correlate the oxygen reduction processes with the characteristics of the oxides layer as a function of the alloy surface treatment (mechanical polishing, electrochemical passivation and pre-reduction, chemical treatment with some acids or with hydrogen peroxide). The second stage has consisted in following the evolution of the oxygen reduction processes and of the characteristics of the oxides layer with the aging of stainless steels in natural and artificial sea-waters. One major bio-film effect appears to be the production of hydrogen peroxide at a concentration level which induces modifications of the oxides layers and, consequently, of the evolution of the oxygen reduction kinetics as well as of the open circuit potential. Electrochemical techniques (voltammetric analysis at rotating disk and ring-disk electrodes, coulometry) combined with a surface analytical method by X-ray photoelectron spectroscopy have been used. The characterisation of the bio-film required the use of microscopy (scanning electronic microscopy, epi-fluorescence microscopy) and microbiological methods (cultures). The in-situ detection of hydrogen peroxide formed inside the bio-film has been performed with a micro-electrode and the results were confirmed with enzymatic methods. (author)

  9. Influence of seawater intrusion on microbial communities in groundwater.

    Science.gov (United States)

    Unno, Tatsuya; Kim, Jungman; Kim, Yumi; Nguyen, Son G; Guevarra, Robin B; Kim, Gee Pyo; Lee, Ji-Hoon; Sadowsky, Michael J

    2015-11-01

    Groundwater is the sole source of potable water on Jeju Island in the Republic of (South) Korea. Groundwater is also used for irrigation and industrial purposes, and it is severely impacted by seawater intrusion in coastal areas. Consequently, monitoring the intrusion of seawater into groundwater on Jeju is very important for health and environmental reasons. A number of studies have used hydrological models to predict the deterioration of groundwater quality caused by seawater intrusion. However, there is conflicting evidence of intrusion due to complicated environmental influences on groundwater quality. Here we investigated the use of next generation sequencing (NGS)-based microbial community analysis as a way to monitor groundwater quality and detect seawater intrusion. Pristine groundwater, groundwater from three coastal areas, and seawater were compared. Analysis of the distribution of bacterial species clearly indicated that the high and low salinity groundwater differed significantly with respect to microbial composition. While members of the family Parvularculaceae were only identified in high salinity water samples, a greater percentage of the phylum Actinobacteria was predominantly observed in pristine groundwater. In addition, we identified 48 shared operational taxonomic units (OTUs) with seawater, among which the high salinity groundwater sample shared a greater number of bacterial species with seawater (6.7%). In contrast, other groundwater samples shared less than 0.5%. Our results suggest that NGS-based microbial community analysis of groundwater may be a useful tool for monitoring groundwater quality and detect seawater intrusion. This technology may also provide additional insights in understanding hydrological dynamics. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Influence of glacial meltwater on global seawater δ234U

    Science.gov (United States)

    Arendt, Carli A.; Aciego, Sarah M.; Sims, Kenneth W. W.; Das, Sarah B.; Sheik, Cody; Stevenson, Emily I.

    2018-03-01

    We present the first published uranium-series measurements from modern Greenland Ice Sheet (GrIS) runoff and proximal seawater, and investigate the influence of glacial melt on global seawater δ234U over glacial-interglacial (g-ig) timescales. Climate reconstructions based on closed-system uranium-thorium (U/Th) dating of fossil corals assume U chemistry of seawater has remained stable over time despite notable fluctuations in major elemental compositions, concentrations, and isotopic compositions of global seawater on g-ig timescales. Deglacial processes increase weathering, significantly increasing U-series concentrations and changing the δ234U of glacial meltwater. Analyses of glacial discharge from GrIS outlet glaciers indicate that meltwater runoff has elevated U concentrations and differing 222Rn concentrations and δ234U compositions, likely due to variations in subglacial residence time. Locations with high δ234U have the potential to increase proximal seawater δ234U. To better understand the impact of bulk glacial melt on global seawater δ234U over time, we use a simple box model to scale these processes to periods of extreme deglaciation. We account for U fluxes from the GrIS, Antarctica, and large Northern Hemisphere Continental Ice Sheets, and assess sensitivity by varying melt volumes, duration and U flux input rates based on modern subglacial water U concentrations and compositions. All scenarios support the hypothesis that global seawater δ234U has varied by more than 1‰ through time as a function of predictable perturbations in continental U fluxes during g-ig periods.

  11. Microbiologically Influenced Corrosion in Copper and Nickel Seawater Piping Systems

    Science.gov (United States)

    1990-09-01

    Influenced Tipton, D. G. and Kain, R. M. 1980. Effect of temperature onCorosiope in Nuclear Power Plants atudy a Mical Gnuide the resistance to pitting of...Monel alloy 400 in seawater. In:Corrosion in Nuclear Power Plants anda Practical ie fr Proceedings of Corrosion 󈨔. Chicago, Illinois: National...Sons Ltd. 441 pp. Quimica . Verink, E.D. and Pourbaix, M. 1971. Use of electrochemical Pope, D. H., Duquette, D. J., Johannes, A. H., and Wayner

  12. Cathodic properties of different stainless steels in natural seawater

    International Nuclear Information System (INIS)

    Johnsen, R.; Bardal, E.

    1985-01-01

    The cathodic properties of a number of stainless steels, which were exposed to natural seawater flowing at 0 to 2.5 m/s and polarized to potentials from -300 to -950 mV SCE, have been studied. The current density development at constant potential and the free corrosion potential during the exposure time were recorded continuously. At the end of the exposure period, after approximately 28 to 36 days of exposure, polarization curves were determined. After one to three weeks of exposure, depending on the water velocity, microbiological activity on the surface caused an increase in the current density requirement of the specimen. An explanation for the mechanism behind the current density increase caused by slime production from marine bacteria may be increased exchange current density, i 0 . There was no measurable calcareous deposit on the stainless steel surfaces at the end of the exposure periods

  13. Comparative ecotoxicity of polystyrene nanoparticles in natural seawater and reconstituted seawater using the rotifer Brachionus plicatilis.

    Science.gov (United States)

    Manfra, L; Rotini, A; Bergami, E; Grassi, G; Faleri, C; Corsi, I

    2017-11-01

    The impact of nanoplastics using model polystyrene nanoparticles (PS NPs), anionic (PS-COOH) and cationic (PS-NH 2 ), has been investigated on the marine rotifer Brachionus plicatilis, a major component of marine zooplanktonic species. The role of different surface charges in affecting PS NP behaviour and toxicity has been considered in high ionic strength media. To this aim, the selected media were standardized reconstituted seawater (RSW) and natural sea water (NSW), the latter resembling more natural exposure scenarios. Hatched rotifer larvae were exposed for 24h and 48h to both PS NPs in the range of 0.5-50μg/ml using PS NP suspensions made in RSW and NSW. No effects on lethality upon exposure to anionic NPs were observed despite a clear gut retention was evident in all exposed rotifers. On the contrary, cationic NPs caused lethality to rotifer larvae but LC 50 values resulted lower in rotifers exposed in RSW (LC 50 =2.75±0.67µg/ml) compared to those exposed in NSW (LC 50 =6.62±0.87µg/ml). PS NPs showed similar pattern of aggregation in both high ionic strength media (RSW and NSW) but while anionic NPs resulted in large microscale aggregates (Z-average 1109 ± 128nm and 998±67nm respectively), cationic NP aggregates were still in nano-size forms (93.99 ± 11.22nm and 108.3 ± 12.79nm). Both PDI and Z-potential of PS NPs slightly differed in the two media suggesting a role of their different surface charges in affecting their behaviour and stability. Our findings confirm the role of surface charges in nanoplastic behaviour in salt water media and provide a first evidence of a different toxicity in rotifers using artificial media (RSW) compared to natural one (NSW). Such evidence poses the question on how to select the best medium in standardized ecotoxicity assays in order to properly assess their hazard to marine life in natural environmental scenarios. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Predatory bacteria as natural modulators of Vibrio parahaemolyticus and Vibrio vulnificus in seawater and oysters

    Science.gov (United States)

    This study shows that naturally occurring Vibrio predatory bacteria (VPB) exert a major role in controlling pathogenic vibrios in seawater and shellfish. The growth and persistence of Vibrio parahaemolyticus (Vp) and Vibrio vulnificus (Vv) were assessed in natural seawater and in the Eastern oyster...

  15. Cathodic protection of carbon steel in natural seawater: Effect of sunlight radiation

    Energy Technology Data Exchange (ETDEWEB)

    Benedetti, Alessandro [Istituto per l' Energetica e le Interfasi, IENI - CNR, Milano, via Roberto Cozzi 53 20125 Milano (Italy)], E-mail: alessandro.benedetti@cnr.it; Magagnin, Luca [Dip. Chimica, Materiali e Ing. Chimica G. Natta, Politecnico di Milano, via Mancinelli 7, 20131 Milano (Italy); Passaretti, Francesca [Istituto per l' Energetica e le Interfasi IENI - CNR, Lecco, c.so Promessi Sposi 29, 23900 Lecco (Italy); Chelossi, Elisabetta; Faimali, Marco [Istituto di Scienze Marine, ISMAR- CNR - Via De Marini 6, 16149, Genova (Italy); Montesperelli, Giampiero [Universita di Roma - Tor Vergata, Dipartimento di Scienze e Tecnologie Chimiche, Via della Ricerca Scientifica 00133, Roma (Italy)

    2009-11-01

    Cathodic protection of metals in seawater is known to be influenced by chemical-physical parameters affecting cathodic processes (oxygen discharge, hydrogen evolution and calcareous deposit precipitation). In shallow seawater, these parameters are influenced by sunlight photoperiod and photosynthetic activity. The results presented here represent the first step in studies dedicated to cathodic protection in shallow photic seawater. This paper reports on carbon steel protected at -850 mV vs. Ag/AgCl (oxygen limiting current regime) in the presence of sunlight radiation but in the absence of biological and photosynthetic activity, the role of which deserves future research. Comparison of results obtained by exposing electrochemical cells to daylight cycles in both biologically inactivated natural seawater and in NaCl 3.5 wt.% solutions showed that sunlight affects current densities and that calcareous deposit interfere with light-currents effects. Sunlight radiation and induced heating of the solution have been separated, highlighting results not otherwise obvious: (1) observed current waves concomitant with sunlight radiation depend fundamentally on solar radiation, (2) solar radiation can determine current enhancements from early to late phases of aragonite crystal growth, (3) a three-day-old CaCO{sub 3} layer reduces but does not eliminate the amplitude of the current waves. Theoretical calculations for oxygen limiting currents and additional field tests showed that sunlight, rather than bulk solution heating, is the main cause of daily current enhancements. This was confirmed by polarizations performed at -850 and -1000 mV vs. Ag/AgCl (constant bulk temperature), during which the electrode was irradiated with artificial lighting. This test also confirmed O{sub 2} discharge to be the cathodic process involved. A mechanism of radiation conversion to heat in the oxygen diffusion layer region is proposed.

  16. Experimental study of composition and influence factors on fouling of stainless steel and copper in seawater

    International Nuclear Information System (INIS)

    Yang, Dazhang; Liu, Jianhua; E, Xiaoxue; Jiang, Linlin

    2016-01-01

    Highlights: • An increase of seawater temperature deteriorates the fouling and corrosion. • The main compositions of crystals are Mg(OH) 2 , Al(OH) 3 and their complex compounds. • The images of the seawater fouling on stainless steel and copper were shown in the paper. • A higher heat flux and A higher Reynolds number are prone to crystallization fouling accumulation in seawater. - Abstract: Metals and alloys are easily fouled in marine environment. It is a big problem for heat exchangers using cooling seawater in power plants or ships. In the paper, a seawater-fouling dynamic test device was built to investigate the composition and influence factors on fouling of stainless steel and copper in the cooling seawater system. Moreover, the static trials were performed to study the fouling and corrosion of stainless steel and copper in marine environment. The experimental results show that the seawater fouling of stainless steel is crystallization fouling, and the main elements of fouling are magnesium and aluminum. In addition, the results show that the seawater fouling of copper is corrosion fouling. In the dynamic experiments, the effects of heat flux and Reynolds number on stainless steel fouling were studied. The results show that higher heat flux and higher Reynolds number of seawater lead to the accumulation of seawater fouling.

  17. Recovery of uranium from seawater. 14. System arrangements for the recovery of uranium from seawater by spherical amidoxime chelating resins utilizing natural seawater motions

    International Nuclear Information System (INIS)

    Egawa, Hiroaki; Kabay, Nalan; Shuto, Taketomi; Jyo, Akinori

    1993-01-01

    In order to evaluate performances of lightly cross-linked highly porous amidoxime resins in uranium-adsorption systems utilizing natural seawater motions, uranium uptake by the resins from seawater was studied by different approaches, such as simulated sea current exposure tests, towing trials, and/or mooring trials. In general, the efficiency of uranium uptake became higher with a decrease in the thickness of packing layers, indicating important roles of fluidization of the resin particles. On the basis of these fundamental data, mooring tests in the natural sea current were designed and conducted. By mooring flat adsorption beds (base area 260 cm 2 , height 3.0 cm) packed with 780 ml of the resin for 40 h, promising uranium uptake as high as 44 mg/kg of resin (9.9 mg/l of resin) was achieved under sea conditions in which the velocity of sea currents and the vertical velocity of waves were 5.5-49.7 cm/s and 3.4-27 cm/s, respectively

  18. Sunlight-enhanced calcareous deposition on cathodic stainless steel in natural seawater

    Digital Repository Service at National Institute of Oceanography (India)

    Eashwar, M.; SathishKumar, P.; Ravishankar, R.; Subramanian, G.

    In replicate series of experiments in natural seawater, one in full darkness and the other in a 1:1 diurnal cycle with as little as 5 percent of natural solar illumination, sunlight promoted calcareous deposition on cathodic stainless steel surfaces...

  19. On the influence of adsorber performance on plant design for the extraction of uranium from seawater

    International Nuclear Information System (INIS)

    Koske, P.H.; Ohlrogge, K.

    1983-01-01

    Based on simple seawater and dissolved uranium balances the influence of specific adsorber parameters on size and design of production plants with fluidized adsorber beds for the extraction of uranium from seawater is discussed. Besides a critical review of two recently published plant designs in the USA and Japan experimentally determined adsorber data for a polyamidoxim (PAO) granulate are presented together with an evaluation of their influence on the key plant parameters. (orig.) [de

  20. Facile Preparation of Porous WO3 Film for Photoelectrochemical Splitting of Natural Seawater

    Science.gov (United States)

    Shi, Yonghong; Li, Yuangang; Wei, Xiaoliang; Feng, Juan; Li, Huajing; Zhou, Wanyi

    2017-12-01

    Sunlight-driven natural seawater splitting provides a promising way for large-scale conversion and storage of solar energy. Here, we develop a facile and low-cost method via a deposition-annealing technique to fabricate porous WO3 film and demonstrate its application as a photoanode for natural seawater splitting. The WO3 film yields a photocurrent density of 1.95 mA cm-2 and possesses excellent stability at 1.23 V (versus RHE), under the illumination of 100 mW cm-2 (AM 1.5G). The photoelectrochemical performance is ascribed to the large surface area and good permeation of the electrolyte into the porous film. Furthermore, the photocurrent density remains almost the same during 3 h continuous light irradiation. The evolution of chlorine gas from seawater splitting was determined with qualitative and quantitative analyses, with a Faradic efficiency of about 56%.

  1. Study of Henna (Lawsonia inermis) as Natural Corrosion Inhibitor for Aluminum Alloy in Seawater

    International Nuclear Information System (INIS)

    Nik, W B Wan; Zulkifli, F; Sulaiman, O; Samo, K B; Rosliza, R

    2012-01-01

    Commercial henna (Lawsonia inermis) was investigated to inhibit the corrosion of aluminum alloy through immersion in seawater. The aluminum alloy (5083) was prepared in size of 25mm × 25mm × 3mm. The immersion test was conducted in seawater with different concentration of henna, 100ppm, 300ppm, 500ppm for duration of 60 days. Four characterizations were performed in this study which was weight loss study, Fourier Transform Infrared (FTIR), Electrochemical Impedance Spectroscopy (EIS) and adsorption isotherm. The results indicated that henna has major constituents of lawsone which contributed to the chemisorptions or adsorption process by forming an isolation layers on the aluminum alloy surface which follows the Langmuir adsorption isotherm. It was found that the protection layer attached on metal was not permanent and precipitation occurred as the time increases. The highest inhibition efficiency was found at 88% (500ppm). This research found that henna is an excellent natural inhibitor for aluminum alloy in seawater.

  2. Influence of fuel costs on seawater desalination options

    International Nuclear Information System (INIS)

    Methnani, Mabrouk

    2007-01-01

    Reference estimates of seawater desalination costs for recent mega projects are all quoted in the range of US$0.50/m 3 . This however does not reflect the recent trends of escalating fossil fuel costs. In order to analyze the effect of these trends, a recently updated version of the IAEA Desalination Economic Evaluation Program, DEEP-3, has been used to compare fossil and nuclear seawater desalination options, under varied fuel cost and interest rate scenarios. Results presented for a gas combined-cycle and a modular high-temperature gas-cooled reactor design, show clear cost advantages for the latter, for both Multi-Effect Distillation (MED) and Reverse Osmosis (RO). Water production cost estimates for the Brayton cycle nuclear option are hardly affected by fuel costs, while combined cycle seawater desalination costs show an increase of more than 40% when fuel costs are doubled. For all cases run, the nuclear desalination costs are lower and if the current trend in fossil fuel prices continues as predicted by pessimist scenarios and the carbon tax carried by greenhouse emissions is enforced in the future, the cost advantage for nuclear desalination will be even more pronounced. Increasing the interest rate from 5 to 8% has a smaller effect than fuel cost variations. It translates into a water cost increase in the range of 10-20%, with the nuclear option being the more sensitive. (author)

  3. Natural modulators of Vibrios in seawater and shellfish

    Science.gov (United States)

    Naturally occurring marine bacteria, Vibrio parahaemolyticus and V. vulnificus, are major threats to the safety of molluscan shellfish in the US and elsewhere. Illnesses range from mild gastrointestinal upset to septicemia and death. In studies on the uptake and persistence of V. parahaemolyticus ...

  4. Temperature Dependence of Uranium and Vanadium Adsorption on Amidoxime-Based Adsorbents in Natural Seawater

    Energy Technology Data Exchange (ETDEWEB)

    Kuo, Li-Jung [Marine Sciences Laboratory, Pacific Northwest National Laboratory, Sequim WA 98382 USA; Gill, Gary A. [Marine Sciences Laboratory, Pacific Northwest National Laboratory, Sequim WA 98382 USA; Tsouris, Costas [Oak Ridge National Laboratory, Oak Ridge TN 37831 USA; Rao, Linfeng [Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley CA 94720 USA; Pan, Horng-Bin [Department of Chemistry, University of Idaho, Moscow ID 83844 USA; Wai, Chien M. [Department of Chemistry, University of Idaho, Moscow ID 83844 USA; Janke, Christopher J. [Oak Ridge National Laboratory, Oak Ridge TN 37831 USA; Strivens, Jonathan E. [Marine Sciences Laboratory, Pacific Northwest National Laboratory, Sequim WA 98382 USA; Wood, Jordana R. [Marine Sciences Laboratory, Pacific Northwest National Laboratory, Sequim WA 98382 USA; Schlafer, Nicholas [Marine Sciences Laboratory, Pacific Northwest National Laboratory, Sequim WA 98382 USA; D' Alessandro, Evan K. [Rosensteil School of Marine and Atmospheric Chemistry, University of Miami, Miami FL 33149 USA

    2018-01-16

    The apparent enthalpy and entropy of the complexation of uranium (VI) and vanadium (V) with amidoxime ligands grafted onto polyethylene fiber was determined using time series measurements of adsorption capacities in natural seawater at three different temperatures. The complexation of uranium was highly endothermic, while the complexation of vanadium showed minimal temperature sensitivity. Amidoxime-based polymeric adsorbents exhibit significantly increased uranium adsorption capacities and selectivity in warmer waters.

  5. Physiological responses of coccolithophores to abrupt exposure of naturally low pH deep seawater.

    Science.gov (United States)

    Iglesias-Rodriguez, Maria Debora; Jones, Bethan M; Blanco-Ameijeiras, Sonia; Greaves, Mervyn; Huete-Ortega, Maria; Lebrato, Mario

    2017-01-01

    Upwelling is the process by which deep, cold, relatively high-CO2, nutrient-rich seawater rises to the sunlit surface of the ocean. This seasonal process has fueled geoengineering initiatives to fertilize the surface ocean with deep seawater to enhance productivity and thus promote the drawdown of CO2. Coccolithophores, which inhabit many upwelling regions naturally 'fertilized' by deep seawater, have been investigated in the laboratory in the context of ocean acidification to determine the extent to which nutrients and CO2 impact their physiology, but few data exist in the field except from mesocosms. Here, we used the Porcupine Abyssal Plain (north Atlantic Ocean) Observatory to retrieve seawater from depths with elevated CO2 and nutrients, mimicking geoengineering approaches. We tested the effects of abrupt natural deep seawater fertilization on the physiology and biogeochemistry of two strains of Emiliania huxleyi of known physiology. None of the strains tested underwent cell divisions when incubated in waters obtained from seawater from ~1,000 m (pH = 7.9; CO2 ~560 p.p.m.; 14-17 μM nitrate) and ~4,800 m (pH = 7.9; CO2 ~600 p.p.m.; 21 μM nitrate). Emiliania huxleyi strain CCMP 88E showed no differences in growth rate or in cellular content or production rates of particulate organic (POC) and inorganic (PIC) carbon and cellular particulate organic nitrogen (PON) between treatments using water from 1,000 m and 4,800 m. However, despite the N:P ratio of seawater being comparable in water from ~1,000 and ~4,800 m, the PON production rates were three times lower in one incubation using water from ~1,000 m compared to values observed in water from ~4,800 m. Thus, the POC:PON ratios were threefold higher in cells that were incubated in ~1,000 m seawater. The heavily calcified strain NZEH exhibited lower growth rates and PIC production rates when incubated in water from ~4,800 m compared to ~1,000 m, while cellular PIC, POC and PON were higher in water from 4,800 m

  6. Feasibilty study of renewable energy powered seawater desalination technology using natural vacuum technique

    Energy Technology Data Exchange (ETDEWEB)

    Ayhan, Teoman; Al Madani, Hussain [Mechanical Engineering Department, College of Engineering, University of Bahrain, P.O. box 32038, Isatown 32036 (Bahrain)

    2010-02-15

    With an ever-increasing population and rapid growth of industrialization, there is great demand for fresh water. Desalination has been a key proponent to meet the future challenges due to decreasing availability of fresh water. However, desalination uses significant amount of energy, today mostly from fossil fuels. It is, therefore, reasonable to rely on renewable energy sources such as solar energy, wind energy, ocean thermal energy, waste heat from the industry and other renewable sources. The present study deals with the energy-efficient seawater desalination system utilizing renewable energy sources and natural vacuum technique. A new desalination technology named Natural Vacuum Desalination is proposed. The novel desalination technique achieve remarkable energy efficiency through the evaporation of seawater under vacuum and will be described in sufficient detail to demonstrate that it requires much less electric energy compared to any conventional desalination plant of fresh water production of similar capacity. The discussion will highlight the main operative and maintenance features of the proposed natural vacuum seawater desalination technology which seems to have promising techno-economic potential providing also advantageous coupling with renewable energy sources. (author)

  7. Role of iron species in the photo-transformation of phenol in artificial and natural seawater

    International Nuclear Information System (INIS)

    Calza, Paola; Massolino, Cristina; Pelizzetti, Ezio; Minero, Claudio

    2012-01-01

    The role played by iron oxides (goethite and akaganeite) and iron(II)/(III) species as photo-sensitizers toward the transformation of organic matter was examined in saline water using phenol as a model molecule. The study was carried out in NaCl 0.7 M solution at pH 8, artificial (ASW) and natural (NSW) seawater, in a device simulating solar light spectrum and intensity. Under illumination phenol decomposition occurs in all the investigated cases. Conversely, dark experiments show that no reaction takes place, implying that phenol transformation is a light- activated process. Following the addition of Fe(II) ions to aerated solutions, Fe(II) is easily oxidized to Fe(III) and hydrogen peroxide is formed. Regardless of the addition of Fe(II) or Fe(III) ions, photo-activated degradation is mediated by Fe(III) species. Several (and different) hydroxylated and halogenated intermediates were identified. In ASW, akaganeite promotes the formation of ortho and para chloro derivatives (2- and 4-chlorophenol, 2,4-dichlorophenol and 2,4,6-trichlorophenol), while goethite induces the formation of 3-chlorophenol and bromophenols. Conversely, Fe(II) or Fe(III) addition causes the formation of 3- and 4-chlorophenol and 2,3- or 3,4-dichlorophenol. 4-Bromophenol was only identified when irradiating Fe(II) spiked solutions. Natural seawater sampled in the Gulf of Trieste, Italy, has been spiked with phenol and irradiated. Phenol photo-induced transformation in NSW mediated by natural photosensitizers occurs and leads to the formation of numerous halophenols, condensed products and nitrophenols. When NSW is spiked with phenol and iron oxides, Fe(II) or Fe(III), halophenols production is enhanced. A close analogy exists between Fe(III), Fe(II)/goethite in ASW and NSW products. Different halophenols production in the natural seawater samples depends on Fe(II)/goethite (above all for 3-chlorophenol, 2,3-dichlorophenol and 4-bromophenol formation) and on Fe(III) colloidal species (3

  8. Trace elements release from volcanic ash to seawater. Natural concentrations in Central Mediterranean sea

    Science.gov (United States)

    Randazzo, L. A.; Censi, P.; Saiano, F.; Zuddas, P.; Aricò, P.; Mazzola, S.

    2009-04-01

    Distributions and concentrations of many minor and trace elements in epicontinental basins, as Mediterranean Sea, are mainly driven to atmospheric fallout from surroundings. This mechanism supplies an estimated yearly flux of about 1000 kg km-2 of terrigenous matter of different nature on the whole Mediterranean basin. Dissolution of these materials and processes occurring at solid-liquid interface along the water column drive the distributions of many trace elements as V, Cr, Mn, Co, Cu, and Pb with contents ranging from pmol l-1 (Co, Cd, Pb) to nmol l-1 scale in Mediterranean seawater, with some local differences in the basin. The unwinding of an oceanographic cruise in the coastal waters of Ionian Sea during the Etna's eruptive activity in summer 2001 led to the almost unique chance to test the effects of large delivery of volcanic ash to a coastal sea water system through the analyses of distribution of selected trace elements along several seawater columns. The collection of these waters and their analyses about V, Cr, Mn, Co, Cu, and Pb contents evidenced trace element concentrations were always higher (about 1 order of magnitude at least) than those measured concentrations in the recent past in Mediterranean seawater, apart from Pb. Progressive increase of concentrations of some elements with depth, sometimes changing in a "conservative" behaviour without any clear reason and the observed higher concentrations required an investigation about interaction processes occurring at solid-liquid interface between volcanic ash and seawater along water columns. This investigation involving kinetic evaluation of trace element leaching to seawater, was carried out during a 6 months time period under laboratory conditions. X-ray investigations, SEM-EDS observations and analyses on freshly-erupted volcanic ash evidenced formation of alteration clay minerals onto glass fraction surfaces. Chemical analyses carried out on coexisting liquid phase demonstrated that trace

  9. Electrochemical evaluation of the influence of pseudomonas sp on aluminium brass in seawater

    International Nuclear Information System (INIS)

    Frontini, Maria Alejandra; Rosso de Sanchez, Susana

    2004-01-01

    The development of a biofilm on metallic surfaces generates serious problems for the acceleration of corrosive processes. The control of the development of the biological film is important because its formation, among other effects, causes fouling of the surface where it has developed, producing differential aeration cells and aggressive metabolites. The influence of surface films was studied by applying electrochemical techniques in artificial seawater with and without bacteria, under different immersion times. Since the pitting potential (Epic) defines the metals' ability to resist pitting corrosion, a measure of susceptibility to pitting in aggressive solutions is considered. The pitting potential was studied in the systems being studied as well as the influence of seawater + ClO - ion biocides on the systems, since the biocides used was sodium hypochlorite (NaCIO). The material used was aluminum brass and a wild bacterial strain was used, which was isolated from the tubes by a heat exchanger from a thermoelectric plant (CW)

  10. Solar driven production of toxic halogenated and nitroaromatic compounds in natural seawater

    Energy Technology Data Exchange (ETDEWEB)

    Calza, Paola [Dipartimento di Chimica Analitica, Universita di Torino, via P. Giuria 5, 10125 Torino (Italy)], E-mail: paola.calza@unito.it; Massolino, Cristina; Pelizzetti, Ezio; Minero, Claudio [Dipartimento di Chimica Analitica, Universita di Torino, via P. Giuria 5, 10125 Torino (Italy)

    2008-07-15

    Natural seawater (NSW) sampled in March and June 2007 in the Gulf of Trieste, Italy, has been spiked with phenol and irradiated in a device simulating solar light spectrum and intensity. Opposite to the case of artificial seawater, for which phenol is slightly degraded by direct photolysis, in NSW the phenol degradation mediated by natural photosensitizers occurs, forming several secondary pollutants, including hydroxyderivatives (1,4-benzoquinone, resorcinol), three chlorophenol isomers, 2,3-dichlorophenol, 2- and 4-bromophenol, 2- and 4-nitrophenol, and several condensed products (2 and 4-phenoxyphenol, 2,2'-, 4,4'- and 2,4-bisphenol). These compounds are toxic to bacteria and other living organisms. Ecotoxicologic effect has been evaluated by using the Vibrio Fischeri luminescent bacteria assay. This technique uses marine organisms, and it is therefore well suited for the study on marine samples. A correlation exists between the intermediates evolution and the toxicity profile, as the largest toxicity is observed when compounds with the lower EC50 (halophenols, phenoxyphenols) are formed at higher concentration.

  11. Enzymatic effect of a bio-film on corrosion of stainless steels immersed in natural seawater

    International Nuclear Information System (INIS)

    L'Hostis, V.

    2002-09-01

    Immersion of stainless steels in natural seawater leads to an ennoblement of their free corrosion potential (Ecor) with time. This evolution is linked to colonization of surface by bacteria, forming a bio-film. Literature synthesis has showed common points between proposed mechanisms, like a modification of cathodic reactions, and importance of hydrogen peroxide, but also differences, as acidity inside bio-films, or chemical composition of the passive layer, or enzymes present inside bio-films. The aim of the study was to precise these hypothesis, and finally mechanisms which leads to increase of Ecor. Experiments with addition of enzymes (glucose oxidase) have been performed and have lead to reproduce the electrochemical behaviour of stainless steels in natural seawater, including the cathodic behaviour. Study of composition of passive film and its semi-conducting properties, analysed respectively by XPS and Mott-Schottky plots, has lead to precise roles of hydrogen peroxide and oxidases. Moreover, study of donor densities of passive film has pointed out the effect of gluconic acid for evolution of cathodic reaction. This enzymatic mechanism has been applied and verified on crevice corrosion, and has been extended to other metallic materials, and other enzymes. (author)

  12. Solar driven production of toxic halogenated and nitroaromatic compounds in natural seawater

    International Nuclear Information System (INIS)

    Calza, Paola; Massolino, Cristina; Pelizzetti, Ezio; Minero, Claudio

    2008-01-01

    Natural seawater (NSW) sampled in March and June 2007 in the Gulf of Trieste, Italy, has been spiked with phenol and irradiated in a device simulating solar light spectrum and intensity. Opposite to the case of artificial seawater, for which phenol is slightly degraded by direct photolysis, in NSW the phenol degradation mediated by natural photosensitizers occurs, forming several secondary pollutants, including hydroxyderivatives (1,4-benzoquinone, resorcinol), three chlorophenol isomers, 2,3-dichlorophenol, 2- and 4-bromophenol, 2- and 4-nitrophenol, and several condensed products (2 and 4-phenoxyphenol, 2,2'-, 4,4'- and 2,4-bisphenol). These compounds are toxic to bacteria and other living organisms. Ecotoxicologic effect has been evaluated by using the Vibrio Fischeri luminescent bacteria assay. This technique uses marine organisms, and it is therefore well suited for the study on marine samples. A correlation exists between the intermediates evolution and the toxicity profile, as the largest toxicity is observed when compounds with the lower EC50 (halophenols, phenoxyphenols) are formed at higher concentration

  13. Study of the oxygen reduction reaction on stainless steel materials in natural seawater. Influence of the bio-film on corrosion processes; Reaction de reduction de l'oxygene sur les aciers inoxydables en eau de mer naturelle. Influence du biofilm sur les processus de corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Le Bozec, N

    2000-01-15

    Bio-film development on stainless steels immersed in natural seawater can have prejudicial consequences on the resistance of these materials to corrosion. The goal of the present study was to get more precise information on the corrosion processes, and especially on the oxygen reduction reaction. As the reaction is linked to the stainless steel surface state, the characterisation of the oxides films (composition, structure, thickness...) is essential to understand the mechanisms and the oxygen reduction kinetic. The first aim of the study has been to correlate the oxygen reduction processes with the characteristics of the oxides layer as a function of the alloy surface treatment (mechanical polishing, electrochemical passivation and pre-reduction, chemical treatment with some acids or with hydrogen peroxide). The second stage has consisted in following the evolution of the oxygen reduction processes and of the characteristics of the oxides layer with the aging of stainless steels in natural and artificial sea-waters. One major bio-film effect appears to be the production of hydrogen peroxide at a concentration level which induces modifications of the oxides layers and, consequently, of the evolution of the oxygen reduction kinetics as well as of the open circuit potential. Electrochemical techniques (voltammetric analysis at rotating disk and ring-disk electrodes, coulometry) combined with a surface analytical method by X-ray photoelectron spectroscopy have been used. The characterisation of the bio-film required the use of microscopy (scanning electronic microscopy, epi-fluorescence microscopy) and microbiological methods (cultures). The in-situ detection of hydrogen peroxide formed inside the bio-film has been performed with a micro-electrode and the results were confirmed with enzymatic methods. (author)

  14. Study of the oxygen reduction reaction on stainless steel materials in natural seawater. Influence of the bio-film on corrosion processes; Reaction de reduction de l'oxygene sur les aciers inoxydables en eau de mer naturelle. Influence du biofilm sur les processus de corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Le Bozec, N

    2000-01-15

    Bio-film development on stainless steels immersed in natural seawater can have prejudicial consequences on the resistance of these materials to corrosion. The goal of the present study was to get more precise information on the corrosion processes, and especially on the oxygen reduction reaction. As the reaction is linked to the stainless steel surface state, the characterisation of the oxides films (composition, structure, thickness...) is essential to understand the mechanisms and the oxygen reduction kinetic. The first aim of the study has been to correlate the oxygen reduction processes with the characteristics of the oxides layer as a function of the alloy surface treatment (mechanical polishing, electrochemical passivation and pre-reduction, chemical treatment with some acids or with hydrogen peroxide). The second stage has consisted in following the evolution of the oxygen reduction processes and of the characteristics of the oxides layer with the aging of stainless steels in natural and artificial sea-waters. One major bio-film effect appears to be the production of hydrogen peroxide at a concentration level which induces modifications of the oxides layers and, consequently, of the evolution of the oxygen reduction kinetics as well as of the open circuit potential. Electrochemical techniques (voltammetric analysis at rotating disk and ring-disk electrodes, coulometry) combined with a surface analytical method by X-ray photoelectron spectroscopy have been used. The characterisation of the bio-film required the use of microscopy (scanning electronic microscopy, epi-fluorescence microscopy) and microbiological methods (cultures). The in-situ detection of hydrogen peroxide formed inside the bio-film has been performed with a micro-electrode and the results were confirmed with enzymatic methods. (author)

  15. Galvanic interactions of HE15 /MDN138 & HE15 /MDN250 alloys in natural seawater

    Science.gov (United States)

    Parthiban, G. T.; Subramanian, G.; Muthuraman, K.; Ramakrishna Rao, P.

    2017-06-01

    HE15 is a heat treatable high strength alloy with excellent machinability find wide applications in aerospace and defence industries. In view of their excellent mechanical properties, workability, machinability, heat treatment characteristics and good resistance to general and stress corrosion cracking, MDN138 & MDN250 have been widely used in petrochemical, nuclear and aerospace industries. The galvanic corrosion behaviour of the metal combinations HE15 /MDN138 and HE15 /MDN250, with 1:1 area ratio, has been studied in natural seawater using the open well facility of CECRI's Offshore Platform at Tuticorin for a year. The open circuit potentials of MDN138, MDN250 and HE15 of the individual metal, the galvanic potential and galvanic current of the couples HE15 /MDN138 and HE15 /MDN250 were periodically monitored throughout the study period. The calcareous deposits on MDN138 and MDN250 in galvanic contact with HE15 were analyzed using XRD. The electrochemical behaviors of MDN138, MDN250 and HE15 in seawater have been studied using an electrochemical work station. The surface characteristics of MDN138 and MDN250 in galvanic contact with HE15 have been examined with scanning electron microscope. The results of the study reveal that HE15 offered required amount of protection to MDN138 & MDN250.

  16. Natural Radionuclides and Heavy Metals Pollution in Seawater at Kuala Langat Coastal Area

    International Nuclear Information System (INIS)

    Sabarina Md Yunus; Zaini Hamzah; Ab Khalik Hj Wood; Ahmad Saat

    2015-01-01

    Rapid industrial developments along the Langat river basin play an important role in contributing to the increases of pollution loading at Kuala Langat coastal area. The major pollutant sources in this area may be originating from human activities such as industrial discharge, domestic sewage, construction, agriculture and pig farming near the tributaries that affects the water quality. In addition, Langat and Semenyih rivers flow through the mining and ex-mining area, which is related to the source of natural radionuclides contamination. Heavy metals in the aquatic environment and more likely to enter the food chain. This study is focusing to the levels of radionuclides and heavy metals in seawater. The samples were collected using appropriate water sampler, which is then acidified until pH 2 and filtered using cellulose acetate 0.45 μm. The concentration of these radionuclides and heavy metals were determined using Inductive Coupled Plasma Mass Spectrometer (ICPMS) after dilution. In general, the radionuclides and heavy metals concentrations are lower than Malaysia Marine Water Quality Standard (MMWQS) except for few locations where the concentration levels above the standards. The higher concentration of pollutant in the seawater may have a toxic effect on sensitive plants and living organisms. The results of pollution levels of these radionuclides and heavy metals were also compared with other studies. (author)

  17. Evolution of oxygen reduction current and biofilm on stainless steels cathodically polarised in natural aerated seawater

    Energy Technology Data Exchange (ETDEWEB)

    Faimali, Marco [ISMAR-CNR, Via De Marini 6, 16149 Genoa (Italy)], E-mail: marco.faimali@ismar.cnr.it; Chelossi, Elisabetta; Garaventa, Francesca; Corra, Christian; Greco, Giuliano; Mollica, Alfonso [ISMAR-CNR, Via De Marini 6, 16149 Genoa (Italy)

    2008-12-01

    The aim of a series of works recently performed at ISMAR was to provide new useful information for a better understanding of the mechanisms by which bacteria settlement causes corrosion on Stainless Steels (SS) and similar active-passive alloys exposed to seawater. In this work, the evolutions of cathodic current, bacteria population, and electronic structure of the passive layer were investigated on SS samples polarised at fixed potentials during their exposure to natural seawater. It was found that, during the first phase of biofilm growth, cathodic current increase is proportional to the number of settled bacteria at each fixed potential. However, the proportionality factor between settled bacteria and cathodic current depends on imposed potential. In particular, the proportionality factor strongly decreases when the potential is increased above a critical value close to -150 mV Ag/AgCl. This effect seems to be correlated with the electronic structure of the passive layer. Indeed, the outer part of the passive layer on tested SS was found to behave like a conductor at potentials more active than -150 mV Ag/AgCl, and like an n-type semiconductor at more noble potentials.

  18. Evolution of oxygen reduction current and biofilm on stainless steels cathodically polarised in natural aerated seawater

    International Nuclear Information System (INIS)

    Faimali, Marco; Chelossi, Elisabetta; Garaventa, Francesca; Corra, Christian; Greco, Giuliano; Mollica, Alfonso

    2008-01-01

    The aim of a series of works recently performed at ISMAR was to provide new useful information for a better understanding of the mechanisms by which bacteria settlement causes corrosion on Stainless Steels (SS) and similar active-passive alloys exposed to seawater. In this work, the evolutions of cathodic current, bacteria population, and electronic structure of the passive layer were investigated on SS samples polarised at fixed potentials during their exposure to natural seawater. It was found that, during the first phase of biofilm growth, cathodic current increase is proportional to the number of settled bacteria at each fixed potential. However, the proportionality factor between settled bacteria and cathodic current depends on imposed potential. In particular, the proportionality factor strongly decreases when the potential is increased above a critical value close to -150 mV Ag/AgCl. This effect seems to be correlated with the electronic structure of the passive layer. Indeed, the outer part of the passive layer on tested SS was found to behave like a conductor at potentials more active than -150 mV Ag/AgCl, and like an n-type semiconductor at more noble potentials

  19. Radiation influence on heterogenous processes in stainless steel contact with sea-water

    International Nuclear Information System (INIS)

    Agayev, T.N.; Garibov, A.A.; Velibekova, G.Z.; Aliyev, A.Q.; Aliyev, S.M.

    2005-01-01

    Full text: Austenitic stainless steel (s.s.) with Cr content 16 %, Ni - 15 % is widely used in nuclear reactors as construction material, for fuel cladding production and also is used in oil and gas production and transportation. They possess comparatively large section of slow neutron capture and as a result high corrosion resistance. In real exploitation condition of nuclear reactors s.s. are exposed to ionizing radiation influence in contact of different media. That's why during their corrosion and destruction processes the surface defect formation processes and further heterogenous processes with their participation are of great importance. The research results of mechanism during radiation-heterogenous processes in nuclear reactor stainless steel contact with sea-water under the influence of γ-radiation in temperature interval 300-1074 K are represented in the given work. Radiolytic processes in water are comprehensively studied and therefore it was taken as model system for dating the surface defects and secondary electrons emitted from metal. The same model system was applied also in sea-water radiolysis processes. It's been established that radiation processes in s.s. lead to molecular hydrogen yield increase and at T=300 K up to 6.5 molec./100 eV. With the temperature increase molecular hydrogen yield increase up to 25.3 molec./100 eV at T≤773 K. During the further temperature increase up to 1073 K radiation constituent of radiation-thermal process in comparison with thermal becomes unnoticeable and W T (H 2 )≅W p (H 2 ). The kinetics of oxide phase formation of investigated sample surface in the result of thermal and radiation-thermal processes in their contact with sea-water has been studied. At that it's been shown that radiation leads to protective oxidation process rate increase and promotes the beginning of stainless steel destruction oxidation in contact with sea-water. At T≥573 K insoluble oxide phase is formed on metal surface that promotes

  20. Crevice corrosion propagation on alloy 625 and alloy C276 in natural seawater

    International Nuclear Information System (INIS)

    McCafferty, E.; Bogar, F.D.; Thomas, E.D. II; Creegan, C.A.; Lucas, K.E.; Kaznoff, A.I.

    1997-01-01

    Chemical composition of the aqueous solution within crevices on two different Ni-Cr-Mo-Fe alloys immersed in natural seawater was determined using a semiquantitative thin-layer chromatographic method. Active crevices were found to contain concentrated amounts of dissolved Ni 2+ , Cr 3+ , Mo 3+ , and Fe 2+ ions. Propagation of crevice corrosion for the two alloys was determined from anodic polarization curves in model crevice solutions based upon stoichiometric dissolution or selective dissolution of alloy components. Both alloys 625 (UNS N06625) and C276 (UNS N10276) underwent crevice corrosion in the model crevice electrolytes. For the model crevice solution based upon selective dissolution of alloy constituents, the anodic dissolution rate for alloy 625 was higher than that for alloy C276. This trend was reversed for the model crevice solution based upon uniform dissolution of alloy constituents

  1. [Natural factors influencing sleep].

    Science.gov (United States)

    Jurkowski, Marek K; Bobek-Billewicz, Barbara

    2007-01-01

    Sleep is a universal phenomenon of human and animal lives, although the importance of sleep for homeo-stasis is still unknown. Sleep disturbances influence many behavioral and physiologic processes, leading to health complications including death. On the other hand, sleep improvement can beneficially influence the course of healing of many disorders and can be a prognostic of health recovery. The factors influencing sleep have different biological and chemical origins. They are classical hormones, hypothalamic releasing and inhibitory hormones, neuropeptides, peptides and others as cytokines, prostaglandins, oleamid, adenosine, nitric oxide. These factors regulate most physiologic processes and are likely elements integrating sleep with physiology and physiology with sleep in health and disorders.

  2. Influence of solution chemistry on the boron content in inorganic calcite grown in artificial seawater

    Science.gov (United States)

    Uchikawa, Joji; Harper, Dustin T.; Penman, Donald E.; Zachos, James C.; Zeebe, Richard E.

    2017-12-01

    The ratio of boron to calcium (B/Ca) in marine biogenic carbonates has been proposed as a proxy for properties of seawater carbonate chemistry. Applying this proxy to planktic foraminifera residing in the surface seawater largely in equilibrium with the atmosphere may provide a valuable handle on past atmospheric CO2 concentrations. However, precise controls on B/Ca in planktic foraminifera remain enigmatic because it has been shown to depend on multiple physicochemical seawater properties. To help establish a firm inorganic basis for interpreting the B/Ca records, we examined the effect of a suite of chemical parameters ([Ca2+], pH, [DIC], salinity and [PO43-]) on B/Ca in inorganic calcite precipitated in artificial seawater. These parameters were primarily varied individually while keeping all others constant, but we also tested the influence of pH and [DIC] at a constant calcite precipitation rate (R) by concurrent [Ca2+] adjustments. In the simple [Ca2+], pH and [DIC] experiments, both R and B/Ca increased with these parameters. In the pH-[Ca2+] and [DIC]-[Ca2+] experiments at constant R, on the other hand, B/Ca was invariant at different pH and decreased with [DIC], respectively. These patterns agree with the behavior of solution [BTotal/DIC] ratio such that, at a fixed [BTotal], it is independent of pH but decreases with [DIC]. Based on these results, R and [BTotal/DIC] ratio appear to be the primary controls on B/Ca in inorganic calcite, suggesting that both B(OH)4- and B(OH)3 are possibly involved in B incorporation. Moreover, B/Ca modestly increased with salinity and [PO43-]. Inorganic calcite precipitated at higher R and in the presence of oxyanions such as SO42- and PO43- in growth solutions often undergoes surface roughening due to formation of crystallographic defects, vacancies and, occasionally, amorphous/hydrous CaCO3. These non-lattice sites may provide additional space for B, particularly B(OH)3. Consequently, besides the macroscopic influence of

  3. Role of H2O2 in the photo-transformation of phenol in artificial and natural seawater

    International Nuclear Information System (INIS)

    Calza, Paola; Campra, Laura; Pelizzetti, Ezio; Minero, Claudio

    2012-01-01

    In previous works, it was observed that phenol photo-induced transformation in natural seawater (NSW) mediated by natural photosensitizers occurs and leads to the formation of numerous hydroxylated, condensed, halogenated and nitroderivatives. Irradiation of NSW added with phenol and iron species had provided the enhanced formation of several halophenols, suggesting a central role played by iron species on the phenol halogenation in marine water. In this paper, we focus on hydrogen peroxide, another key photosensitizer, and its interaction with iron species. The ability of Fe(II)/Fe(III) and H 2 O 2 species to act as photo-sensitizers towards the transformation of organic compounds in seawater was investigated under simulated solar radiation. Light activation is necessary to induce the transformation of phenol, as no degradation occurs in the dark when either H 2 O 2 or iron/H 2 O 2 are initially added to artificial seawater (ASW). Fe(II) is easily transformed into Fe(III), assessing that a Fenton reaction (dark, Fe(II)/H 2 O 2 ) does not take place in marine environment, in favour of a photo-activated reaction involving Fe(III) and H 2 O 2 . When NSW is spiked with H 2 O 2 and Fe(III), halophenols' and nitrophenols' concentration decreases and completely disappears at high hydrogen peroxide concentration. Since Fe(II) and Fe(III) in spiked seawater induce an enhanced formation of haloderivatives, an excess of hydrogen peroxide act as scavenger towards the photo-produced chloro/bromo radicals, so hindering halogenation process in seawater. Hence, even if hydrogen peroxide efficiently induces the ·OH radical formation, and could then promote the phenol phototransformation, nevertheless it is negligibly involved in the production of the intermediates formed during phenol photolysis in seawater, whose formation is necessarily linked to other photosensitizer species. - Highlights: ► Hydrogen peroxide-mediated solar-driven transformations of pollutant in seawater are

  4. Inorganic speciation of dissolved elements in seawater: the influence of pH on concentration ratios

    Directory of Open Access Journals (Sweden)

    Byrne Robert H

    2002-01-01

    Full Text Available Assessments of inorganic elemental speciation in seawater span the past four decades. Experimentation, compilation and critical review of equilibrium data over the past forty years have, in particular, considerably improved our understanding of cation hydrolysis and the complexation of cations by carbonate ions in solution. Through experimental investigations and critical evaluation it is now known that more than forty elements have seawater speciation schemes that are strongly influenced by pH. In the present work, the speciation of the elements in seawater is summarized in a manner that highlights the significance of pH variations. For elements that have pH-dependent species concentration ratios, this work summarizes equilibrium data (S = 35, t = 25°C that can be used to assess regions of dominance and relative species concentrations. Concentration ratios of complex species are expressed in the form log[A]/[B] = pH - C where brackets denote species concentrations in solution, A and B are species important at higher (A and lower (B solution pH, and C is a constant dependent on salinity, temperature and pressure. In the case of equilibria involving complex oxy-anions (MOx(OHy or hydroxy complexes (M(OHn, C is written as pKn = -log Kn or pKn* = -log Kn* respectively, where Kn and Kn* are equilibrium constants. For equilibria involving carbonate complexation, the constant C is written as pQ = -log(K2lKn [HCO3-] where K2l is the HCO3 - dissociation constant, Kn is a cation complexation constant and [HCO3-] is approximated as 1.9 × 10-3 molar. Equilibrium data expressed in this manner clearly show dominant species transitions, ranges of dominance, and relative concentrations at any pH.

  5. Effects of triclosan on bacterial community composition and 'Vibrio' populations in natural seawater microcosms

    Directory of Open Access Journals (Sweden)

    Keri Ann Lydon

    2017-05-01

    Full Text Available Pharmaceuticals and personal care products, including antimicrobials, can be found at trace levels in treated wastewater effluent. Impacts of chemical contaminants on coastal aquatic microbial community structure and pathogen abundance are unknown despite the potential for selection through antimicrobial resistance. In particular, 'Vibrio', a marine bacterial genus that includes several human pathogens, displays resistance to the ubiquitous antimicrobial compound triclosan. Here we demonstrated through use of natural seawater microcosms that triclosan (at a concentration of ~5 ppm can induce a significant 'Vibrio' growth response (68–1,700 fold increases in comparison with no treatment controls for three distinct coastal ecosystems: Looe Key Reef (Florida Keys National Marine Sanctuary, Doctors Arm Canal (Big Pine Key, FL, and Clam Bank Landing (North Inlet Estuary, Georgetown, SC. Additionally, microbial community analysis by 16 S rRNA gene sequencing for Looe Key Reef showed distinct changes in microbial community structure with exposure to 5 ppm triclosan, with increases observed in the relative abundance of 'Vibrio'naceae (17-fold, Pseudoalteromonadaceae (65-fold, Alteromonadaceae (108-fold, Colwelliaceae (430-fold, and Oceanospirillaceae (1,494-fold. While the triclosan doses tested were above concentrations typically observed in coastal surface waters, results identify bacterial families that are potentially resistant to triclosan and/or adapted to use triclosan as a carbon source. The results further suggest the potential for selection of 'Vibrio' in coastal environments, especially sediments, where triclosan may accumulate at high levels.

  6. Influences of Scavenging and Removal of Surfactants by Bubble Processing on Primary Marine Aerosol Production from North Atlantic Seawater

    Science.gov (United States)

    Duplessis, P.; Chang, R.; Frossard, A. A.; Keene, W. C.; Maben, J. R.; Long, M. S.; Beaupre, S. R.; Kieber, D. J.; Kinsey, J. D.; Zhu, Y.; Lu, X.; Bisgrove, J.

    2017-12-01

    Primary marine aerosol particles (PMA) are produced by bursting bubbles from breaking waves at the air-sea interface and significantly modulate atmospheric chemical transformations and cloud properties. Surfactants in bulk seawater rapidly (seconds) adsorb onto fresh bubble surfaces forming organic films that influence size, rise velocity, bursting behavior, and associated PMA emissions. During a cruise on the R/V Endeavor in September and October 2016, PMA production from biologically productive and oligotrophic seawater was investigated at four stations in the western North Atlantic Ocean. PMA were produced in a high-capacity generator via turbulent mixing of seawater and clean air in a Venturi nozzle. When the flow of fresh seawater through the generator was turned off, surfactant depletion via bubble processing resulted in greater PMA mass production efficiencies per unit air detrained but had no consistent influence on number production efficiencies. The greater (factor of 3) production efficiencies of organic matter associated with PMA generated with the Venturi relative to those generated with frits during previous campaigns contributed to a faster depletion of surfactants from the seawater reservoir and corresponding divergence in response.

  7. A screening method for the isolation of polyhydroxyalkanoate-producing purple non-sulfur photosynthetic bacteria from natural seawater

    Directory of Open Access Journals (Sweden)

    Mieko Higuchi-Takeuchi

    2016-09-01

    Full Text Available Polyhydroxyalkanoates (PHAs are a family of biopolyesters accumulated by a variety of microorganisms as carbon and energy storage under starvation conditions. We focused on marine purple non-sulfur photosynthetic bacteria as host microorganisms for PHA production and developed a method for their isolation from natural seawater. To identify novel PHA-producing marine purple non-sulfur photosynthetic bacteria, natural seawaters were cultured in nutrient-rich medium for purple non-sulfur photosynthetic bacteria, and twelve pink- or red-pigmented colonies were picked up. Gas chromatography mass spectrometry analysis revealed that four isolates synthesized PHA at levels ranging from 0.5 to 24.4 wt% of cell dry weight. The 16S ribosomal RNA sequence analysis revealed that one isolate (HM2 showed 100% identity to marine purple non-sulfur photosynthetic bacteria. In conclusion, we have demonstrated in this study that PHA-producing marine purple non-sulfur photosynthetic bacteria can be isolated from natural seawater under nutrient-rich conditions.

  8. Temporal Stability of the Microbial Community in Sewage-Polluted Seawater Exposed to Natural Sunlight Cycles and Marine Microbiota

    Science.gov (United States)

    Sassoubre, Lauren M.; Yamahara, Kevan M.

    2015-01-01

    Billions of gallons of untreated wastewater enter the coastal ocean each year. Once sewage microorganisms are in the marine environment, they are exposed to environmental stressors, such as sunlight and predation. Previous research has investigated the fate of individual sewage microorganisms in seawater but not the entire sewage microbial community. The present study used next-generation sequencing (NGS) to examine how the microbial community in sewage-impacted seawater changes over 48 h when exposed to natural sunlight cycles and marine microbiota. We compared the results from microcosms composed of unfiltered seawater (containing naturally occurring marine microbiota) and filtered seawater (containing no marine microbiota) to investigate the effect of marine microbiota. We also compared the results from microcosms that were exposed to natural sunlight cycles with those from microcosms kept in the dark to investigate the effect of sunlight. The microbial community composition and the relative abundance of operational taxonomic units (OTUs) changed over 48 h in all microcosms. Exposure to sunlight had a significant effect on both community composition and OTU abundance. The effect of marine microbiota, however, was minimal. The proportion of sewage-derived microorganisms present in the microcosms decreased rapidly within 48 h, and the decrease was the most pronounced in the presence of both sunlight and marine microbiota, where the proportion decreased from 85% to 3% of the total microbial community. The results from this study demonstrate the strong effect that sunlight has on microbial community composition, as measured by NGS, and the importance of considering temporal effects in future applications of NGS to identify microbial pollution sources. PMID:25576619

  9. Effects of copper and titanium on the corrosion behavior of newly fabricated nanocrystalline aluminum in natural seawater

    International Nuclear Information System (INIS)

    Sherif, El-Sayed M.; Ammar, Hany Rizk; Khalil, Khalil Abdelrazek

    2014-01-01

    Graphical abstract: - Highlights: • We fabricated nanocrystalline Al and some of its alloys by mechanical alloying method. • The corrosion behavior of the fabricated materials in natural seawater was reported. • We found that Al suffers both uniform and localized corrosion in the seawater. • The presence of Cu significantly decreased the corrosion of Al. • The addition of Ti to the Al–Cu alloy presented more protection to Al against corrosion. - Abstract: Fabrication of a newly nanocrystalline Al and two of its alloys, namely Al–10%Cu; and Al–10%Cu–5%Ti has been carried out using mechanical alloying (MA) technique. The corrosion behavior of these materials in aerated stagnant Arabian Gulf seawater (AGSW) at room temperature has been reported. Cyclic potentiodynamic polarization (CPP), chronoamperometric current-time (CCT) and electrochemical impedance spectroscopy (EIS) measurements along with scanning electron microscopy (SEM) and X-ray energy dispersive (EDX) investigations were employed to report the corrosion behavior of the fabricated materials. All results indicated that Al suffers both uniform and localized corrosion in the AGSW test solution. The presence of 10%Cu decreases the corrosion current density, the anodic and cathodic currents and corrosion rate and increases the corrosion resistance of Al. The addition of 5%Ti to the Al–10%Cu alloy produced further decreases in the corrosion parameters. Measurements together confirmed that the corrosion of the fabricated materials in AGSW decreases in the order Al > Al–10%Cu > Al–10%Cu–5%Ti

  10. Effects of copper and titanium on the corrosion behavior of newly fabricated nanocrystalline aluminum in natural seawater

    Energy Technology Data Exchange (ETDEWEB)

    Sherif, El-Sayed M., E-mail: esherif@ksu.edu.sa [Mechanical Engineering Department, College of Engineering, King Saud University, P.O. Box 800, Al-Riyadh 11421 (Saudi Arabia); Electrochemistry and Corrosion Laboratory, Department of Physical Chemistry, National Research Centre , (NRC), Dokki, 12622, Cairo 8 (Egypt); Ammar, Hany Rizk [Metallurgical and Materials Engineering Department, Faculty of Petroleum and Mining Engineering, Suez University, Suez (Egypt); Khalil, Khalil Abdelrazek [Metallurgical and Materials Engineering Department, Faculty of Petroleum and Mining Engineering, Suez University, Suez (Egypt); Mechanical Design and Materials Department, Faculty of Energy Engineering, Aswan University, Aswan (Egypt)

    2014-05-01

    Graphical abstract: - Highlights: • We fabricated nanocrystalline Al and some of its alloys by mechanical alloying method. • The corrosion behavior of the fabricated materials in natural seawater was reported. • We found that Al suffers both uniform and localized corrosion in the seawater. • The presence of Cu significantly decreased the corrosion of Al. • The addition of Ti to the Al–Cu alloy presented more protection to Al against corrosion. - Abstract: Fabrication of a newly nanocrystalline Al and two of its alloys, namely Al–10%Cu; and Al–10%Cu–5%Ti has been carried out using mechanical alloying (MA) technique. The corrosion behavior of these materials in aerated stagnant Arabian Gulf seawater (AGSW) at room temperature has been reported. Cyclic potentiodynamic polarization (CPP), chronoamperometric current-time (CCT) and electrochemical impedance spectroscopy (EIS) measurements along with scanning electron microscopy (SEM) and X-ray energy dispersive (EDX) investigations were employed to report the corrosion behavior of the fabricated materials. All results indicated that Al suffers both uniform and localized corrosion in the AGSW test solution. The presence of 10%Cu decreases the corrosion current density, the anodic and cathodic currents and corrosion rate and increases the corrosion resistance of Al. The addition of 5%Ti to the Al–10%Cu alloy produced further decreases in the corrosion parameters. Measurements together confirmed that the corrosion of the fabricated materials in AGSW decreases in the order Al > Al–10%Cu > Al–10%Cu–5%Ti.

  11. Analysis of a natural draught tower in the circulation seawater system of nuclear power plant of Laguna Verde

    International Nuclear Information System (INIS)

    Tijerina S, F.; Vargas A, A.

    2009-10-01

    The analysis of a natural draught tower in open circuit for the cooling system of seawater circulation on the nuclear power plant of Laguna Verde, it is based on conditions of 2027 MWt and 2317 MWt, where the flows of circulation water system hardly vary and whose purpose will be, to cool the seawater circulation. The circulation water system is used as heat drain in main condenser of turbo generator to condense the nuclear vapor. The annual average temperature in the seawater at present is of 26 C to the entrance to circulation water system and it is vary in accordance with the time of year. The mean temperature of leaving of circulation water system to the sea is of 41 C. Having a cooling tower to reduce the entrance temperature to the circulation water system, it improves the efficiency of thermal transfer in condenser, it improves the vacuum in condenser giving more operative margin to avoid condenser losses by air entrances and nuclear power plant shutdowns, as well as for to improve the efficiency of operative balance of nuclear power plant, also it prevents the impact in thermal transfer efficiency in condenser by the climatic change. (Author)

  12. Simultaneous effects of environmental factors on motile Aeromonas dynamics in an urban effluent and in the natural seawater.

    Science.gov (United States)

    Maalej, Sami; Mahjoubi, Amira; Elazri, Chafai; Dukan, Sam

    2003-07-01

    Seasonal dynamics of motile Aeromonas in a treated urban effluent and in natural seawater along the Sfax coast (Mediterranean sea, Tunisia) were measured over a year concurrently with seven environmental factors, and compared with those of faecal coliforms. Counts for Aeromonas from a standard plate count method, ranged from 1.48 x 10(5)CFU.100 ml(-1) to 2.2 x 10(8)CFU.100 ml(-1) in the effluent and from 7.9 x 10(3)CFU.100 ml(-1) to undetectable level in the surface marine waters. Contrary to faecal coliforms, the Aeromonas dynamics exhibited a seasonal distribution in seawater which was inverse of the seasonal distribution in the sewage: From the end of November 1998 to April 1999 (cold period), Aeromonas counts increased in the treated effluent, while it decreased very rapidly in seawater. From May to October (warm period), Aeromonas abundance decreased in the effluent but showed an increasing fluctuating trend in the marine waters with a maximum in late summer/early autumn when the temperatures were around 22-23 degrees C. Multiple correlation and regression analyses suggest, by the coefficient of determination (R(2)), that 42% of variance in Aeromonas number changes in the treated effluent, may be explained by only turbidity, radiation and Aeromonas density in the previous sample, while 37% of variance in marine ecosystem were explained by radiance and conductivity. Furthermore, the t statistics and their p values and the coefficient of partial determination (r(2)) indicated that radiance contributed the most (r(2)=0.3184, t=-3.2, p=0.0041) to the dynamics of motile Aeromonas in seawater, when combined with conductivity. The models relevant for changes in faecal coliforms abundance incorporated turbidity, radiance in the effluent and conductivity, pH, radiance, turbidity in coastal marine environment. These models explain 66% and 73% of the observed cell number fluctuation, with turbidity (r(2)=0.529, t=5.08, p=0.0001) and conductivity (r(2)=0.5407, t=4.97, p=0

  13. An Investigation of Anaerobic Processes in Fuel/Natural Seawater Environments

    Science.gov (United States)

    2012-02-08

    separated esters and glycerin. Biodiesel contains no sulfur. In the United States the term "biodiesel" is standardized as fatty acid methyl ester ( FAME ...crude oil remaining. Biodiesel is produced from vegetable oils by converting the triglyceride oils to methyl (or ethyl) esters with a process known...water from the environment. Microbial growth in seawater can be limited by nutrients, including carbon. Biodiesel methyl esters are quite sparingly

  14. Influence of Fracture Width on Sealability in High-Strength and Ultra-Low-Permeability Concrete in Seawater

    OpenAIRE

    Fukuda, Daisuke; Nara, Yoshitaka; Hayashi, Daisuke; Ogawa, Hideo; Kaneko, Katsuhiko

    2013-01-01

    For cementitious composites and materials, the sealing of fractures can occur in water by the precipitation of calcium compounds. In this study, the sealing behavior in a macro-fractured high-strength and ultra-low-permeability concrete (HSULPC) specimen was investigated in simulated seawater using micro-focus X-ray computed tomography (CT). In particular, the influence of fracture width (0.10 and 0.25 mm) on fracture sealing was investigated. Precipitation occurred mainly at the outermost pa...

  15. The corrosion behaviour of stainless steels in natural seawater: results of an european collaborative project

    Energy Technology Data Exchange (ETDEWEB)

    Scotto, V.; Mollica, A. [Institut de Recherches de la Siderurgie Francaise (IRSID), 78 - Saint-Germain-en-Laye (France); Feron, D. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Direction des Technologies Avancees; Rogne, T.; Steinsmo, U. [Stiftelsen for Industriell og Teknisk Forskning (SINTEF), Trondheim (Norway); Compere, C.; Festy, D.; Audouard, J.P.; Taxen, C.; Thierry, D.

    1996-12-31

    One of the goals of the European collaborative Project `Marine Bio-film on Stainless steels: effects, monitoring and prevention`, started in 1992 and partially funded by the European Communities in the framework of the Marine Science and Technologies Program, was to give some conclusive and general remarks regarding the possible link, outlined in literature, between aerobic bio-film settlement and both the increased risk of localized corrosion onset and the propagation rate of ongoing localized corrosion on Stainless Steels. For this purpose several SS types of European production (austenitic and duplex), in form of tubes and plates, with and without artificial crevices preformed on their surfaces, have been exposed to flowing and quite seawater (flow rate from 0 to 1.5 m/s), at different marine stations (respectively located in the Mediterranean Sea, in the Eastern Atlantic, in the North and Baltic Seas) and the tests were repeated during each season of the year when seawater temperatures ranged from 6 up to 28 deg C. During each exposure, the SS free corrosion potentials were recorded. (authors).

  16. The influence of dissolved petroleum hydrocarbon residues on natural phytoplankton biomass

    Digital Repository Service at National Institute of Oceanography (India)

    Shailaja, M.S.

    on phytoplankton biomass varies depending on the nature rather than the quantity of petroleum hydrocarbons present. Culture studies with unialgal Nitzschia sp. in seawater collected from selected stations in the study area as well as in artificial seawater spiked...

  17. Filtration–UV irradiation as an option for mitigating the risk of microbiologically influenced corrosion of subsea construction alloys in seawater

    International Nuclear Information System (INIS)

    Machuca, Laura L.; Jeffrey, Robert; Bailey, Stuart I.; Gubner, Rolf; Watkin, Elizabeth L.J.; Ginige, Maneesha P.; Kaksonen, Anna H.; Heidersbach, Krista

    2014-01-01

    Highlights: •Biofilms ennobled E corr of offshore construction alloys in natural seawater. •Filtration–UV irradiation delayed biofilm growth and activity on alloys. •Localized corrosion in seawater was lowered by the use of filtration–UV irradiation. •Biofilm community composition was affected by both substratum and seawater treatment. •Filtration–UV irradiation can be an ecofriendly practice for protection against MIC. -- Abstract: The effect of filtration–UV irradiation of seawater on the biofilm activity on several offshore structural alloys was evaluated in a continuous flow system over 90 days. Biofilms ennobled the electrode potential by +400 to 500 mV within a few days of exposure to raw untreated seawater. Filtration–UV irradiation of the seawater delayed the ennoblement of the steels for up to 40 days and lowered localized corrosion rates in susceptible alloys. Ennobling biofilms were composed of microbial cells, diatoms and extracellular polymeric substances and the bacterial community in biofilms was affected by both the alloy composition and seawater treatment

  18. Influence of Chlorination and Choice of Materials on Fouling in Cooling Water System under Brackish Seawater Conditions

    Directory of Open Access Journals (Sweden)

    Pauliina Rajala

    2016-06-01

    Full Text Available Cooling systems remove heat from components and industrial equipment. Water cooling, employing natural waters, is typically used for cooling large industrial facilities, such as power plants, factories or refineries. Due to moderate temperatures, cooling water cycles are susceptible to biofouling, inorganic fouling and scaling, which may reduce heat transfer and enhance corrosion. Hypochlorite treatment or antifouling coatings are used to prevent biological fouling in these systems. In this research, we examine biofouling and materials’ degradation in a brackish seawater environment using a range of test materials, both uncoated and coated. The fouling and corrosion resistance of titanium alloy (Ti-6Al-4V, super austenitic stainless steel (254SMO and epoxy-coated carbon steel (Intershield Inerta160 were studied in the absence and presence of hypochlorite. Our results demonstrate that biological fouling is intensive in cooling systems using brackish seawater in sub-arctic areas. The microfouling comprised a vast diversity of bacteria, archaea, fungi, algae and protozoa. Chlorination was effective against biological fouling: up to a 10–1000-fold decrease in bacterial and archaeal numbers was detected. Chlorination also changed the diversity of the biofilm-forming community. Nevertheless, our results also suggest that chlorination enhances cracking of the epoxy coating.

  19. Influence of Chlorination and Choice of Materials on Fouling in Cooling Water System under Brackish Seawater Conditions.

    Science.gov (United States)

    Rajala, Pauliina; Bomberg, Malin; Huttunen-Saarivirta, Elina; Priha, Outi; Tausa, Mikko; Carpén, Leena

    2016-06-15

    Cooling systems remove heat from components and industrial equipment. Water cooling, employing natural waters, is typically used for cooling large industrial facilities, such as power plants, factories or refineries. Due to moderate temperatures, cooling water cycles are susceptible to biofouling, inorganic fouling and scaling, which may reduce heat transfer and enhance corrosion. Hypochlorite treatment or antifouling coatings are used to prevent biological fouling in these systems. In this research, we examine biofouling and materials' degradation in a brackish seawater environment using a range of test materials, both uncoated and coated. The fouling and corrosion resistance of titanium alloy (Ti-6Al-4V), super austenitic stainless steel (254SMO) and epoxy-coated carbon steel (Intershield Inerta160) were studied in the absence and presence of hypochlorite. Our results demonstrate that biological fouling is intensive in cooling systems using brackish seawater in sub-arctic areas. The microfouling comprised a vast diversity of bacteria, archaea, fungi, algae and protozoa. Chlorination was effective against biological fouling: up to a 10-1000-fold decrease in bacterial and archaeal numbers was detected. Chlorination also changed the diversity of the biofilm-forming community. Nevertheless, our results also suggest that chlorination enhances cracking of the epoxy coating.

  20. Influence of Fracture Width on Sealability in High-Strength and Ultra-Low-Permeability Concrete in Seawater

    Directory of Open Access Journals (Sweden)

    Katsuhiko Kaneko

    2013-06-01

    Full Text Available For cementitious composites and materials, the sealing of fractures can occur in water by the precipitation of calcium compounds. In this study, the sealing behavior in a macro-fractured high-strength and ultra-low-permeability concrete (HSULPC specimen was investigated in simulated seawater using micro-focus X-ray computed tomography (CT. In particular, the influence of fracture width (0.10 and 0.25 mm on fracture sealing was investigated. Precipitation occurred mainly at the outermost parts of the fractured surface of the specimen for both fracture widths. While significant sealing was observed for the fracture width of 0.10 mm, sealing was not attained for the fracture width of 0.25 mm within the observation period (49 days. Examination of the sealed regions on the macro-fracture was performed using a three-dimensional image registration technique and applying image subtraction between the CT images of the HSULPC specimen before and after maintaining the specimen in simulated seawater. The temporal change of the sealing deposits for the fracture width of 0.10 mm was much larger than that for the fracture width of 0.25 mm. Therefore, it is concluded that the sealability of the fracture in the HSULPC is affected by the fracture width.

  1. Influence of Fracture Width on Sealability in High-Strength and Ultra-Low-Permeability Concrete in Seawater.

    Science.gov (United States)

    Fukuda, Daisuke; Nara, Yoshitaka; Hayashi, Daisuke; Ogawa, Hideo; Kaneko, Katsuhiko

    2013-06-25

    For cementitious composites and materials, the sealing of fractures can occur in water by the precipitation of calcium compounds. In this study, the sealing behavior in a macro-fractured high-strength and ultra-low-permeability concrete (HSULPC) specimen was investigated in simulated seawater using micro-focus X-ray computed tomography (CT). In particular, the influence of fracture width (0.10 and 0.25 mm) on fracture sealing was investigated. Precipitation occurred mainly at the outermost parts of the fractured surface of the specimen for both fracture widths. While significant sealing was observed for the fracture width of 0.10 mm, sealing was not attained for the fracture width of 0.25 mm within the observation period (49 days). Examination of the sealed regions on the macro-fracture was performed using a three-dimensional image registration technique and applying image subtraction between the CT images of the HSULPC specimen before and after maintaining the specimen in simulated seawater. The temporal change of the sealing deposits for the fracture width of 0.10 mm was much larger than that for the fracture width of 0.25 mm. Therefore, it is concluded that the sealability of the fracture in the HSULPC is affected by the fracture width.

  2. Influence of sulfide concentration on the corrosion behavior of pure copper in synthetic seawater

    International Nuclear Information System (INIS)

    Taniguchi, Naoki; Kawasaki, Manabu

    2008-01-01

    Corrosion rate and stress corrosion cracking (SCC) behavior of pure copper under anaerobic conditions were studied by immersion tests and slow strain rate tests (SSRT) in synthetic seawater containing Na 2 S. The corrosion rate was increased with sulfide concentration both in simple saline solution and in bentnite-sand mixture. The results of SSRT showed that copper was susceptible to intergranular attack; selective dissolution at lower sulfide concentration (less than 0.005 M) and SCC at higher sulfide concentration (0.01 M). It was expected that if the sulfide concentration in groundwater is less than 0.001 M, pure copper is possible to exhibit superior corrosion resistance under anaerobic condition evident by very low corrosion rates and immunity to SCC. In such a low sulfide environment, copper overpack has the potential to achieve super-long lifetimes exceeding several tens of thousands years according to long-term simulations of corrosion based on diffusion of sulfide in buffer material

  3. Morpho-physiological response of Acacia auriculiformis as influenced by seawater induced salinity stress

    Energy Technology Data Exchange (ETDEWEB)

    Haque, A.; Rahman, M.; Nihad, S.A.I.; Howlader, R.A.; Akand, M.H.

    2016-07-01

    Aim of the study: To evaluate the morpho-physiological changes of Acacia auriculiformis in response to seawater induced salinity stress along with its tolerance limit. Area of study: Bangabandhu Sheikh Mujibur Rahman Agricultural University, Bangladesh. Material and methods: Three saline treatments (4, 8, 12 dS m-1) were applied to six-month aged Acacia auriculiformis seedlings from January 2014 to June 2014 and the tap water was used as control treatment. To observe salinity effects, the following parameters were measured by using various established techniques: plant height and leaf number, plant biomass, shoot and root distribution as well as shoot and root density, water uptake capacity (WUC), water saturation deficit (WSD) and water retention capacity (WRC), exudation rate, and cell membrane stability. Main results: Diluted seawater caused a notable reduction in shoot and root distribution in addition to shoot and root density, though plant height, leaf number and plant biomass were found to be decreased to some extent compared to control plants. Water status of the plant also altered when plants were subjected to salinity stress. Nevertheless, membrane stability revealed good findings towards salinity tolerance. Research highlights: Considering the above facts, despite salinity exerts some negative effects on overall plant performance, interestingly the percent reduction value doesn’t exceed 50% as compared to control plants, and the plants were successful to tolerate salinity stress till the end of the experiment (150 days) through adopting some tolerance mechanisms. Abbreviations used: BSMRAU (Bangabandhu Sheikh Mujibur Rahman Agricultural University); RCBD (randomized complete block design); DATI (days after treatment imposition); RWC (relative water content); WUC (water uptake capacity); WSD (water saturation deficit); WRC (water retention capacity); FW (fresh weight); DW (dry weight); TW (turgid weight); ROS (reactive oxygen species). (Author)

  4. Influence of flow velocity on biofilm growth in a tubular heat exchanger-condenser cooled by seawater.

    Science.gov (United States)

    Trueba, Alfredo; García, Sergio; Otero, Félix M; Vega, Luis M; Madariaga, Ernesto

    2015-01-01

    The influence of flow velocity (FV) on the heat transfer process in tubes made from AISI 316L stainless steel in a heat exchanger-condenser cooled by seawater was evaluated based on the characteristics of the resulting biofilm that adhered to the internal surface of the tubes at velocities of 1, 1.2, 1.6, and 3 m s(-1). The results demonstrated that at a higher FV, despite being more compact and consistent, the biofilm was thinner with a lower concentration of solids, and smoother, which favoured the heat transfer process within the equipment. However, higher velocities increase the initial cost of the refrigerating water-pumping equipment and its energy consumption cost to compensate for the greater pressure drops produced in the tube. The velocity of 1.6 m s(-1) represented the equilibrium between the advantages and disadvantages of the variables analysed for the test conditions in this study.

  5. Potentiodynamic study of Al-Mg alloy with superhydrophobic coating in photobiologically active/not active natural seawater.

    Science.gov (United States)

    Benedetti, Alessandro; Cirisano, Francesca; Delucchi, Marina; Faimali, Marco; Ferrari, Michele

    2016-01-01

    Superhydrophobic coating technology is regarded as an attractive possibility for the protection of materials in a sea environment. DC techniques are a useful tool to characterize metals' behavior in seawater in the presence/absence of coatings and/or corrosion inhibitors. In this work, investigations concerning Al-5%Mg alloy with and without a sprayed superhydrophobic coating were carried out with potentiodynamic scans in photobiologically active and not active seawater (3 weeks of immersion). In not photobiologically active seawater, the presence of the superhydrophobic coating did not prevent pitting corrosion. With time, the coating underwent local exfoliations, but intact areas still preserved superhydrophobicity. In photobiologically active seawater, on samples without the superhydrophobic coating (controls) pitting was inhibited, probably due to the adsorption of organic compounds produced by the photobiological activity. After 3 weeks of immersion, the surface of the coating became hydrophilic due to diatom coverage. As suggested by intermediate observations, the surface below the diatom layer is suspected of having lost its superhydrophobicity due to early stages of biofouling processes (organic molecule adsorption and diatom attachment/gliding). Polarization curves also revealed that the metal below the coating underwent corrosion inhibiting phenomena as observed in controls, likely due to the permeation of organic molecules through the coating. Hence, the initial biofouling stages (days) occurring in photobiologically active seawater can both accelerate the loss of superhydrophobicity of coatings and promote corrosion inhibition on the underlying metal. Finally, time durability of superhydrophobic surfaces in real seawater still remains the main challenge for applications, where the early stages of immersion are demonstrated to be of crucial importance. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Microbially influenced corrosion: studies on enterobacteria isolated from seawater environment and influence of toxic metals on bacterial biofilm and bio-corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Bermond-Tilly, D.; Pineau, S.; Dupont-Morral, I. [Corrodys, 50 - Equeurdreville (France); Janvier, M.; Grimont, P.A.D. [Institut Pasteur, Unite BBPE, 75 - Paris (France)

    2004-07-01

    Full text of publication follows: The most widely involved bacteria in Microbially Induced Corrosion (MIC usually called bio-corrosion) are sulfate/thiosulfate-reducing bacteria. The sulfate-reducing bacteria (SRB) are major contributors to the anaerobic bio-corrosion of steel. However, corrosion process of pipelines (or off shores platforms) was found to be associated with many other bacteria. These bacteria are able to produce sulfides from the reduction of thiosulfate in anaerobic conditions. By this way, a thiosulfate-reducing non sulfate-reducing bacteria, Dethiosulfovibrio peptidovorans, showed a significant corrosive activity similar to or higher than that recorded for SRB involved in bio-corrosion, (Magot et al., 1997). Furthermore, a bacteria, Citrobacter amalonaticus, which belongs to the family of the Enterobacteriaceae, is involved in severe pitting corrosion process (Angeles Chavez et al., 2002). Recently, some bacteria (Citrobacter freundii, Proteus mirabilis and Klebsiella planticola characterized as belonging to the family of Enterobacteriaceae) were isolated from biofilm developed on carbon steel coupons immersed in natural seawater. The latter bacteria were also associated in severe pitting corrosion process on carbon steel coupons (Bermond-Tilly et al., 2003). Biofilm forms a protective layer, reducing the exposure of the metal surface to the external environment. However, bacteria included in the biofilm could also cause localized corrosion by consuming cathodic hydrogen from the steel or by producing corrosive metabolic end products and by the Extracellular Polymeric Substances (EPS) production. Thus, EPS can also play an important role in the corrosion of the metals (e.g. can complex metal ions). However, sulfate/thiosulfate-reducing bacteria and some Enterobacteria are highly efficient to bioremediation by precipitation of toxic metals from wastewater as metal sulfides. Recently it was shown that toxic metal may be involved in the formation

  7. Determination of arsenate in natural pH seawater using a manganese-coated gold microwire electrode

    Energy Technology Data Exchange (ETDEWEB)

    Gibbon-Walsh, Kristoff [Department of Earth and Ocean Sciences, University of Liverpool, Liverpool L69 3GP (United Kingdom); Salauen, Pascal, E-mail: Salaun@liv.ac.uk [Department of Earth and Ocean Sciences, University of Liverpool, Liverpool L69 3GP (United Kingdom); Berg, Constant M.G. van den, E-mail: Vandenberg@liv.ac.uk [Department of Earth and Ocean Sciences, University of Liverpool, Liverpool L69 3GP (United Kingdom)

    2012-01-13

    Highlights: Black-Right-Pointing-Pointer Determination of arsenic(V) in water of neutral pH. Black-Right-Pointing-Pointer An unusual redox couple of elemental Mn/As{sup V} reduces As{sup V} to As{sup III}. Black-Right-Pointing-Pointer Novel manganese coated gold microwire electrode. - Abstract: Direct electrochemical determination of arsenate (As{sup V}) in neutral pH waters is considered impossible due to electro-inactivity of As{sup V}. As{sup III} on the other hand is readily plated as As{sup 0} on a gold electrode and quantified by anodic stripping voltammetry (ASV). We found that the reduction of As{sup V} to As{sup III} was mediated by elemental Mn on the electrode surface in a novel redox couple in which 2 electrons are exchanged causing the Mn to be oxidised to Mn{sup II}. Advantage is taken of this redox couple to enable for the first time the electrochemical determination of As{sup V} in natural waters of neutral pH including seawater by ASV using a manganese-coated gold microwire electrode. Thereto Mn is added to excess ({approx}1 {mu}M Mn) to the water leading to a Mn coating during the deposition of As on the electrode at a deposition potential of -1.3 V. Deposition of As{sup 0} from dissolved As{sup V} caused elemental Mn to be re-oxidised to Mn{sup II} in a 1:1 molar ratio providing evidence for the reaction mechanism. The deposited As{sup V} is subsequently quantified using an ASV scan. As{sup III} interferes and should be quantified separately at a more positive deposition potential of -0.9 V. Combined inorganic As is quantified after oxidation of As{sup III} to As{sup V} using hypochlorite. The microwire electrode was vibrated during the deposition step to improve the sensitivity. The detection limit was 0.2 nM As{sup V} using a deposition time of 180 s.

  8. Seawater bicarbonate removal during hydrothermal circulation

    Science.gov (United States)

    Proskurowski, G. K.; Seewald, J.; Sylva, S. P.; Reeves, E.; Lilley, M. D.

    2013-12-01

    High temperature fluids sampled at hydrothermal vents represent a complex alteration product of water-rock reactions on a multi-component mixture of source fluids. Sources to high-temperature hydrothermal samples include the 'original' seawater present in the recharge limb of circulation, magmatically influenced fluids added at depth as well as any seawater entrained during sampling. High-temperature hydrothermal fluids are typically enriched in magmatic volatiles, with CO2 the dominant species, characterized by concentrations of 10's-100's of mmol/kg (1, 2). Typically, the high concentration of CO2 relative to background seawater bicarbonate concentrations (~2.3 mmol/kg) obscures a full analysis of the fate of seawater bicarbonate during high-temperature hydrothermal circulation. Here we present data from a suite of samples collected over the past 15 years from high-temperature hydrothermal vents at 9N, Endeavour, Lau Basin, and the MAR that have endmember CO2 concentrations less than 10 mmol/kg. Using stable and radiocarbon isotope measurements these samples provide a unique opportunity to examine the balance between 'original' seawater bicarbonate and CO2 added from magmatic sources. Multiple lines of evidence from multiple hydrothermal settings consistently points to the removal of ~80% of the 'original' 2.3 mmol/kg seawater bicarbonate. Assuming that this removal occurs in the low-temperature, 'recharge' limb of hydrothermal circulation, this removal process is widely occurring and has important contributions to the global carbon cycle over geologic time. 1. Lilley MD, Butterfield DA, Lupton JE, & Olson EJ (2003) Magmatic events can produce rapid changes in hydrothermal vent chemistry. Nature 422(6934):878-881. 2. Seewald J, Cruse A, & Saccocia P (2003) Aqueous volatiles in hydrothermal fluids from the Main Endeavour Field, northern Juan de Fuca Ridge: temporal variability following earthquake activity. Earth and Planetary Science Letters 216(4):575-590.

  9. Establishing Natural Nootropics: Recent Molecular Enhancement Influenced by Natural Nootropic.

    Science.gov (United States)

    Suliman, Noor Azuin; Mat Taib, Che Norma; Mohd Moklas, Mohamad Aris; Adenan, Mohd Ilham; Hidayat Baharuldin, Mohamad Taufik; Basir, Rusliza

    2016-01-01

    Nootropics or smart drugs are well-known compounds or supplements that enhance the cognitive performance. They work by increasing the mental function such as memory, creativity, motivation, and attention. Recent researches were focused on establishing a new potential nootropic derived from synthetic and natural products. The influence of nootropic in the brain has been studied widely. The nootropic affects the brain performances through number of mechanisms or pathways, for example, dopaminergic pathway. Previous researches have reported the influence of nootropics on treating memory disorders, such as Alzheimer's, Parkinson's, and Huntington's diseases. Those disorders are observed to impair the same pathways of the nootropics. Thus, recent established nootropics are designed sensitively and effectively towards the pathways. Natural nootropics such as Ginkgo biloba have been widely studied to support the beneficial effects of the compounds. Present review is concentrated on the main pathways, namely, dopaminergic and cholinergic system, and the involvement of amyloid precursor protein and secondary messenger in improving the cognitive performance.

  10. Establishing Natural Nootropics: Recent Molecular Enhancement Influenced by Natural Nootropic

    OpenAIRE

    Noor Azuin Suliman; Che Norma Mat Taib; Mohamad Aris Mohd Moklas; Mohd Ilham Adenan; Mohamad Taufik Hidayat Baharuldin; Rusliza Basir

    2016-01-01

    Nootropics or smart drugs are well-known compounds or supplements that enhance the cognitive performance. They work by increasing the mental function such as memory, creativity, motivation, and attention. Recent researches were focused on establishing a new potential nootropic derived from synthetic and natural products. The influence of nootropic in the brain has been studied widely. The nootropic affects the brain performances through number of mechanisms or pathways, for example, dopaminer...

  11. The nature of Mesoarchaean seawater and continental weathering in 2.85 Ga banded iron formation, Slave craton, NW Canada

    Science.gov (United States)

    Haugaard, Rasmus; Ootes, Luke; Creaser, Robert A.; Konhauser, Kurt O.

    2016-12-01

    Banded iron formations (BIF) have been extensively used as proxies to infer the chemical composition of ancient bulk seawater. However, their proximity to ancient crust suggests that they might also be used to reveal the composition of emergent continental landmass at the time of their deposition. Here we use the combination of geochemistry and Sm-Nd isotopes on a layer-by-layer basis to interpret the relative contributions of hydrothermal, hydrogenous and terrestrial input to one of the oldest documented Superior-type BIF in the world. The ∼2.85 Ga Central Slave Cover Group BIF is deposited within a rift basin related to a continental margin and is found associated with basement gneisses, as well as shoreline and shallow-shelf type facies, such as fuchsitic quartzite and pebble-to-cobble conglomerate, that confirm a near-shore depositional setting for the BIF. The BIF ranges from a pure chemical oxide (magnetite)-silicate (grunerite + actinolite) sediment with low Al2O3 (aged BIF. High-resolution geochemistry shows that there is more silica (19.4 wt.% SiO2) in the iron bands than iron (8.7 wt.% Fe2O3) in the silica bands, implying that dissolved Fe2+ came to the BIF site in pulses and that silica likely represents background deposition. Consistently radiogenic εNd(t) values for the iron bands (average +1.7) show that the dissolved REY in the source water during ferric iron precipitation was provided by submarine hydrothermal fluids with relatively uniform 143Nd/144Nd. The silica bands, by contrast, reveal high variation in seawater 143Nd/144Nd as evident from the bimodal εNd(t) distribution with one segment exhibiting negative εNd(t) values averaging -1.1 and another with positive εNd(t) values averaging +2.5. This suggests input of dissolved REY into the upper seawater from weathering of isotopically different crustal components in the source region. Collectively, we speculate that the low REY in the upper seawater and the overall low Ni content implies a

  12. Corrosion of mild steel, copper and brass in crude oil / seawater mixture

    Digital Repository Service at National Institute of Oceanography (India)

    PrabhaDevi, S.; Sawant, S.S.; Wagh, A.B.

    Mild steel, copper and brass coupons were introduced in natural seawater containing varying amount of crude oil. Mild steel showed higher rate of corrosion in seawater containing oil and lower corrosion rate in natural as well as artificial seawater...

  13. Effect of natural phosphate to remove silver interference in the detection of mercury(II in aquatic algae and seawater samples

    Directory of Open Access Journals (Sweden)

    S. Lahrich

    2016-03-01

    Full Text Available A silver particles impregnated onto natural phosphate (Ag/NP was synthesized using reaction in solid state. The obtained powder was characterized by X-ray diffraction (XRD analysis and scanning electron microscopy (SEM. The (Ag/NP was used as modifier of carbon paste electrode (CPE to determine mercury by square wave voltammetry. The calibration graph obtained is linear from 1.0 × 10−8 mol·L−1 to 1.0 × 10−5 mol·L−1 at preconcentration time of 5 min, percentage loading of 7%, with correlation coefficient of 0.993. The limits of detection (DL,3σ and quantification (QL,10σ were 5.8 × 10−9 mol·L−1 and 19.56 × 10−9 mol·L−1 respectively. The repeatability of the method expressed as relative standard deviation (R.S.D. is 2.1% (n = 8. The proposed method was successfully applied to determine mercury(II in aquatic algae and seawater samples. Keywords: Natural phosphate, Square wave voltammetry, Silver, Mercury, Aquatic algae, Seawater

  14. An investigation of microbial diversity in crude oil & seawater injection systems and microbiologically influenced corrosion (MIC) of linepipe steels under different exposure conditions

    Science.gov (United States)

    AlAbbas, Faisal Mohammed

    During oil and gas operations, pipeline networks are subjected to different corrosion deterioration mechanisms that result from the interaction between the fluid process and the linepipe steel. Among these mechanisms is microbiologically influenced corrosion (MIC) that results from accelerated deterioration caused by different indigenous microorganisms that naturally reside in the hydrocarbon and associated seawater injection systems. The focus of this research is to obtain comprehensive understanding of MIC. This work has explored the most essential elements (identifications, implications and mitigations) required to fully understand MIC. Advanced molecular-based techniques, including sequencing of 16S rRNA genes via 454 pyrosequencing methodologies, were deployed to provide in-depth understanding of the microbial diversity associated with crude oil and seawater injection systems and their relevant impact on MIC. Key microbes including sulfate reducing bacteria (SRB) and iron reducing bacteria (IRB) were cultivated from sour oil well field samples. The microbes' phylotypes were identified in the laboratory to gain more thorough understanding of how they impact microbial corrosion. Electrochemical and advanced surface analytical techniques were used for corrosion evaluations of linepipe carbon steels (API 5L X52 and X80) under different exposure conditions. On the identification front, 454 pyrosequencing of both 16S rRNA genes indicated that the microbial communities in the corrosion products obtained from the sour oil pipeline, sweet crude pipeline and seawater pipeline were dominated by bacteria, though archaeal sequences (predominately Methanobacteriaceae and Methanomicrobiaceae) were also identified in the sweet and sour crude oil samples, respectively. The dominant bacterial phylotypes in the sour crude sample included members of the Thermoanaerobacterales, Synergistales, and Syntrophobacterales. In the sweet crude sample, the dominant phylotypes included

  15. Establishing Natural Nootropics: Recent Molecular Enhancement Influenced by Natural Nootropic

    Directory of Open Access Journals (Sweden)

    Noor Azuin Suliman

    2016-01-01

    Full Text Available Nootropics or smart drugs are well-known compounds or supplements that enhance the cognitive performance. They work by increasing the mental function such as memory, creativity, motivation, and attention. Recent researches were focused on establishing a new potential nootropic derived from synthetic and natural products. The influence of nootropic in the brain has been studied widely. The nootropic affects the brain performances through number of mechanisms or pathways, for example, dopaminergic pathway. Previous researches have reported the influence of nootropics on treating memory disorders, such as Alzheimer’s, Parkinson’s, and Huntington’s diseases. Those disorders are observed to impair the same pathways of the nootropics. Thus, recent established nootropics are designed sensitively and effectively towards the pathways. Natural nootropics such as Ginkgo biloba have been widely studied to support the beneficial effects of the compounds. Present review is concentrated on the main pathways, namely, dopaminergic and cholinergic system, and the involvement of amyloid precursor protein and secondary messenger in improving the cognitive performance.

  16. Surface chemical characteristics of coal fly ash particles after interaction with seawater under natural deep sea conditions

    International Nuclear Information System (INIS)

    Brami, Y.; Shemesh, A.; Cohen, H.; Herut, B.

    1999-01-01

    The surface chemical characteristics of coal fly ash (CFA) before and after interaction with Mediterranean deep seawater was studied by X-ray photoelectron spectroscopy (XPS). Significantly lower values of Si, Ca, and S and higher values of Mg and Cl were found in the retrieved CFA as compared to fresh CFA. It is suggested that hydrolysis of the oxide matrixes results in an alkaline environment which rapidly leads to several chemical reactions. The two most important are (a) dissolution of the amorphous silicate and the calcium phases and (b) precipitation of Mg(OH) 2 -brucite. A depth profile of the retrieved CFA was measured by both line-shape analysis of the XPS spectra and by consecutive cycle of sputtering. The thickness of the brucite layer is estimated to be 1.3 nm

  17. In vitro photooxidation of a crude Iranian petroleum maltenic fraction as a film over seawater in natural simulated conditions and identification of photoproducts

    International Nuclear Information System (INIS)

    Nahri-Niknafs, B.; Ghotbesharif, S.J.; Taghvaei, S.; Rustayian, A.H.

    2004-01-01

    Photooxidation is a transformation pathway for oil spilled in the marine environment. Most crude oils spilled at sea spread rapidly to form slicks over a large surface areas. Oil entering the seas can have a harmful impact on marine ecosystems and on the commercial and recreation resources of coastal areas. The spilled oil undergoes physical changes such as dispersion, photooxidation, evaporation, and dissolution. These changes are accompanied by changes in density, viscosity and interfacial tension. It is important to understand the effect petroleum photooxidation and degradation in order to determine the fate of the spilled oil in a marine environment. This study presents a reliable method for examining the nature of the photoproducts and the composition of the residual hydrocarbons on an oil film over seawater. In this study, the maltenic fraction of Iranian oil was exposed to sunlight as a film of oil over seawater. The authors examined the effect of ultraviolet illumination of gas chromatography-mass spectrometry and Fourier Transform Infrared analytical methods. The study revealed that the saturated hydrocarbons were resistant, but the aromatic hydrocarbons were found to be sensitive to photochemical degradation. The sensitivity of aromatic compounds to photooxidation was increased by increasing the size and alkyl substitution. 14 refs., 2 tabs., 1 fig

  18. Analysis of a natural draught tower in the circulation seawater system of nuclear power plant of Laguna Verde; Analisis de una torre de tiro natural en el sistema de agua de circulacion de mar de la central nucleoelectrica Laguna Verde

    Energy Technology Data Exchange (ETDEWEB)

    Tijerina S, F.; Vargas A, A. [Comision Federal de Electricidad, Central Nucleoelectrica Laguna Verde, Subgerencia de Ingenieria, Carretera Veracruz-Medellin Km. 7.5, Veracruz (Mexico)], e-mail: francisco.tijerina@cfe.gob.mx

    2009-10-15

    The analysis of a natural draught tower in open circuit for the cooling system of seawater circulation on the nuclear power plant of Laguna Verde, it is based on conditions of 2027 MWt and 2317 MWt, where the flows of circulation water system hardly vary and whose purpose will be, to cool the seawater circulation. The circulation water system is used as heat drain in main condenser of turbo generator to condense the nuclear vapor. The annual average temperature in the seawater at present is of 26 C to the entrance to circulation water system and it is vary in accordance with the time of year. The mean temperature of leaving of circulation water system to the sea is of 41 C. Having a cooling tower to reduce the entrance temperature to the circulation water system, it improves the efficiency of thermal transfer in condenser, it improves the vacuum in condenser giving more operative margin to avoid condenser losses by air entrances and nuclear power plant shutdowns, as well as for to improve the efficiency of operative balance of nuclear power plant, also it prevents the impact in thermal transfer efficiency in condenser by the climatic change. (Author)

  19. Mimicking Seawater For Culturing Marine Bacteria

    DEFF Research Database (Denmark)

    Rygaard, Anita Mac; Sonnenschein, Eva; Gram, Lone

    2015-01-01

    Only about 1% of marine bacteria have been brought into culture using traditional techniques. The purpose of this study was to investigate if mimicking the natural bacterial environment can increase culturability.We used marine substrates containing defined algal polymers or gellan gum as solidif......Only about 1% of marine bacteria have been brought into culture using traditional techniques. The purpose of this study was to investigate if mimicking the natural bacterial environment can increase culturability.We used marine substrates containing defined algal polymers or gellan gum...... as solidifying agents, and enumerated bacteria from seawater and algal exudates. We tested if culturability could be influenced by addition of quorum sensing signals (AHLs). All plates were incubated at 15°C. Bacterial counts (CFU/g) from algal exudates from brown algae were highest on media containing algal...... polymers. In general, bacteria isolated from algal exudates preferred more rich media than bacteria isolated from seawater. Overall, culturability ranged from 0.01 to 0.8% as compared to total cell count. Substitution of agar with gellan gum increased the culturability of seawater bacteria approximately...

  20. Effect of aging time and aging temperature on fatigue and fracture behavior of 6063 aluminum alloy under seawater influence

    International Nuclear Information System (INIS)

    Siddiqui, R.A.; Abdul-Wahab, S.A.; Pervez, T.

    2008-01-01

    This paper describes experimentally the effect of seawater corrosion, aging time, and aging temperature on the fatigue resistance property of 6063 aluminum alloy. The 6063 aluminum alloy that was used for the study was heat treated and soaked in seawater for different intervals of time between 2 and 30 weeks. It was found that the maximum fatigue resistance property in the 6063 aluminum alloy was observed when aged between 7 and 9 h and heat treated at temperatures between 160 o C and 200 o C. Generally at constant load, the results indicated that the number of cycles to fail the 6063 aluminum alloy decreased with increasing the soaking time in seawater. Moreover, fracture surfaces were considered and studied under a scanning electron microscope (SEM). The results showed that the brittle fracture pattern tended to occur with the increase in aging time and temperature. The fatigue striations were observed very clearly at low and peak aging temperature. The increase in the fatigue resistance property with aging time was linked with the vacancies assisted diffusion mechanism and also by the hindering of dislocation movement by impure atoms

  1. Natural polyphenols: Influence on membrane transporters

    Directory of Open Access Journals (Sweden)

    Saad Abdulrahman Hussain

    2016-03-01

    Full Text Available Accumulated evidences have focused on the use of natural polyphenolic compounds as nutraceuticals, since they showed a wide range of bioactivities and exhibited protection against variety of age related disorders. Polyphenols have variable potencies to interact, and hence alter the activities of various transporter proteins, many of them classified as ATP-Binding Cassette transporters, like multidrug resistance protein (MDRP, and p-glycoprotein (P-gp. Some of the efflux transporters are generally linked with anticancer and antiviral drug resistance; in this context, polyphenols may be beneficial in modulating drug resistance by increasing the efficacy of anticancer and antiviral drugs. Additionally, these effects were implicated to explain the influence of dietary polyphenols on drug efficacy as result of food-drug interactions. However, limited data are available about the influence of these components on uptake transporters. Therefore, the objective of this article is to review the potential efficacies of polyphenols in modulating the functional integrity of uptake transporter proteins, including those terminated the effect of neurotransmitters, and their possible influence in neuropharmacology. [J Complement Med Res 2016; 5(1.000: 97-104

  2. Chlorine-36 in seawater

    International Nuclear Information System (INIS)

    Argento, David C.; Stone, John O.; Keith Fifield, L.; Tims, Stephen G.

    2010-01-01

    Natural cosmogenic 36 Cl found in seawater originates from spallation of atmospheric 40 Ar, capture of secondary cosmic-ray neutrons by dissolved 35 Cl, and river runoff which contains 36 Cl produced in situ over the surface of the continents. The long residence time of chloride in the ocean and long half-life of 36 Cl compared to the oceanic mixing time should result in a homogenous 36 Cl/Cl ratio throughout the ocean. Production by neutron capture in the course of nuclear weapons testing should be insignificant averaged over the oceans as a whole, but may have led to regions of elevated 36 Cl concentration. Previous attempts to measure the 36 Cl/Cl ratio of seawater have been hindered by interferences, contamination, or insufficient analytic sensitivity. Here we report preliminary measurements on seawater samples, which demonstrate that the 36 Cl/Cl ratio is 0.5 ± 0.3 x 10 -15 , in reasonable agreement with calculated contributions from the sources listed above.

  3. Natural Radium Isotopes in Particulate and Dissolved Phases of Seawater and Rainwater at the West Coast Peninsular Malaysia Caused by Coal-Fired Power Plant

    Directory of Open Access Journals (Sweden)

    Nik Azlin Nik Ariffin

    2010-07-01

    Full Text Available The concentration levels of natural radium isotopes such as 226Ra and 228Ra were measured in the atmospheric samples including rainwater, total suspended solids (TSSrw and marine environment samples collected around the Kapar coal-fired power plant from September 2006 to February 2008. Activity concentration of 228Ra and 226Ra in rainwater showed the higher concentrations compared to the seawater. The mean activities of 226Ra and 228Ra in rainwater at Kapar were 20.45±4.50 mBq/L and 74.82±25.38 mBq/L, respectively. Meanwhile the levels in total suspended solids (TSSrw of rainwater showed 226.99±52.57 Bq/kg for 226Ra and 439.92±186.17 Bq/kg for 228Ra. The measurements of radium isotopes concentration in rainwater at coal-fired power plant in Kapar are found in relation to their sources and application as tracers in lower atmosphere. The mean value of pH in rainwater during this study is pH 5.51 slightly acidic as lowest value for the standard of clean rainwater. Radium in seawater also strong adsorption onto total suspended solids with the distribution coefficient, Kd values of 228Ra and 226Ra ranged from 0.054 × 104 to 163.90 × 104 L/g and between 0.49 × 104 to 191.54 × 104 L/g, respectively.

  4. Natural language metaphors covertly influence reasoning.

    Directory of Open Access Journals (Sweden)

    Paul H Thibodeau

    Full Text Available Metaphors pervade discussions of social issues like climate change, the economy, and crime. We ask how natural language metaphors shape the way people reason about such social issues. In previous work, we showed that describing crime metaphorically as a beast or a virus, led people to generate different solutions to a city's crime problem. In the current series of studies, instead of asking people to generate a solution on their own, we provided them with a selection of possible solutions and asked them to choose the best ones. We found that metaphors influenced people's reasoning even when they had a set of options available to compare and select among. These findings suggest that metaphors can influence not just what solution comes to mind first, but also which solution people think is best, even when given the opportunity to explicitly compare alternatives. Further, we tested whether participants were aware of the metaphor. We found that very few participants thought the metaphor played an important part in their decision. Further, participants who had no explicit memory of the metaphor were just as much affected by the metaphor as participants who were able to remember the metaphorical frame. These findings suggest that metaphors can act covertly in reasoning. Finally, we examined the role of political affiliation on reasoning about crime. The results confirm our previous findings that Republicans are more likely to generate enforcement and punishment solutions for dealing with crime, and are less swayed by metaphor than are Democrats or Independents.

  5. Biodegradation of n-alkanes on oil-seawater interfaces at different temperatures and microbial communities associated with the degradation.

    Science.gov (United States)

    Lofthus, Synnøve; Netzer, Roman; Lewin, Anna S; Heggeset, Tonje M B; Haugen, Tone; Brakstad, Odd Gunnar

    2018-04-01

    Oil biodegradation studies have mainly focused on microbial processes in dispersions, not specifically on the interfaces between the oil and the seawater in the dispersions. In this study, a hydrophobic adsorbent system, consisting of Fluortex fabrics, was used to investigate biodegradation of n-alkanes and microbial communities on oil-seawater interfaces in natural non-amended seawater. The study was performed over a temperature range from 0 to 20 °C, to determine how temperature affected biodegradation at the oil-seawater interfaces. Biodegradation of n-alkanes were influenced both by seawater temperature and chain-length. Biotransformation rates of n-alkanes decreased by reduced seawater temperature. Low rate coefficients at a seawater temperature of 0 °C were probably associated with changes in physical-chemical properties of alkanes. The primary bacterial colonization of the interfaces was predominated by the family Oceanospirillaceae at all temperatures, demonstrating the wide temperature range of these hydrocarbonoclastic bacteria. The mesophilic genus Oleibacter was predominant at the seawater temperature of 20 °C, and the psychrophilic genus Oleispira at 5 and 0 °C. Upon completion of n-alkane biotransformation, other oil-degrading and heterotrophic bacteria became abundant, including Piscirickettsiaceae (Cycloclasticus), Colwelliaceae (Colwellia), Altermonadaceae (Altermonas), and Rhodobacteraceae. This is one of a few studies that describe the biodegradation of oil, and the microbial communities associated with the degradation, directly at the oil-seawater interfaces over a large temperature interval.

  6. Sorption isolation of strontium from seawater

    International Nuclear Information System (INIS)

    Avramenko, V.A.; Zheleznov, V.V.; Kaplun, E.V.; Sokol'nitskaya, T.A.; Yukhkam, A.A.

    2001-01-01

    Sorption isolation of strontium from seawater is considered and prospects of use of selective adsorbents for purification of seawater or liquid radioactive wastes mixed with seawater from 90 Sr are discussed. Comparative analysis of sorptive properties of adsorbents of different nature is done. It is shown that sorption-reagent materials developed by authors can to afford effective separation of 90 Sr from seawater. Possible mechanism of strontium sorption by these adsorbents is considered. The prospect of their use for purification of liquid radioactive wastes from strontium is shown [ru

  7. Feasibility analysis of the Primary Loop of Pool-Type Natural Circulating Nuclear Reactor Dedicated to Seawater Desalination

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Woonho; Jeong, Yong Hoon [KAIST, Daejeon (Korea, Republic of)

    2016-05-15

    In this study, the feasibility of natural circulation was evaluated for the reference plant AHR400 (Advanced Heating Reactor 400MWth). AHR400 is a pool-type desalination-dedicated nuclear reactor. As a consequence, AHR400 has low operating pressure and temperature which provides large safety margin. Removal of the reactor coolant pump from the AHR400 will enforce integrity of the reactor vessel and passive safety feature. Therefore, the study also tried to find out optimized primary loop design to achieve total natural circulation of the coolant. Natural circulation capacity of the primary loop of the desalination dedicated nuclear reactor AHR400 was evaluated. It was concluded that to remove RCP from the AHR400 and operates the reactor only by natural circulation of the coolant is impossible. Decreased core power as half make removal of RCP possible with 15m central height difference between the core and IHXs. Furthermore, validation and modification of pressure loss coefficients by small-scaled natural circulation experiment at a pool-type reactor would provide more accurate results.

  8. Chemical effect on ozone deposition over seawater

    Science.gov (United States)

    Surface layer resistance plays an important role in determining ozone deposition velocity over seawater. Recent studies suggest that surface layer resistance over sea-water is influenced by wind-speed and chemical interaction at the air-water interface. Here, we investigate the e...

  9. 14C labelling of algal pigments to estimate the contribution of different taxa to primary production in natural seawater

    NARCIS (Netherlands)

    Gieskes, Winfried W.C.; Kraaij, Gijs W; Buma, Anita

    1993-01-01

    Several attempts have been made in the past to measure taxon-specific growth rates in natural phytoplankton populations in order to evaluate the conditions leading to success of individual taxa, to estimate the specific role of the various taxonomic components of algae in the food web and in

  10. Materials resistant to seawater

    International Nuclear Information System (INIS)

    Lunde, L.

    1986-03-01

    The report is a summary of the topics discussed at a two-day seminar at Institute for Energy Technology, Kjeller in August 1985. Experience with seawater corrosion in Nordic power reactor plants was discussed. There was also input from Danish experience with seawater corrosion in coal fired power plants. The following topics were dealt with: Experience in seawater cooling system materials, chlorination of seawater systems, and accelerated laboratory tests for stainless steels

  11. Perchlorate in seawater

    Energy Technology Data Exchange (ETDEWEB)

    Martinelango, P. Kalyani [Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061 (United States); Tian Kang [Institute of Environmental and Human Health, Texas Tech University, Lubbock, TX 79409 (United States); Dasgupta, Purnendu K. [Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061 (United States)]. E-mail: Sandyd@ttu.edu

    2006-05-10

    There has been no reliable published data on the presence of perchlorate in seawater. Seaweeds are among the most important plant life in the ocean and are good sources of iodine and have been widely used as food and nutritional supplement. Perchlorate is known to inhibit the transport of iodide by the sodium iodide symporter (NIS), present e.g., in the thyroid and mammary glands. With perchlorate being increasingly detected in drinking water, milk and various other foods, increasing the iodide intake through inexpensive natural supplements may be an attractive solution for maintaining iodine assimilation. We report here measurable concentrations of perchlorate in several samples of seawater (detectable in about half the samples analyzed). We also report the iodide and perchlorate concentrations of 11 different species of seaweed and the corresponding bioconcentration factors (BCF) for perchlorate and iodide, relative to the seawater from which they were harvested. All seaweed samples came from the same region, off the coast of Northeastern Maine. Concentrations of iodide and perchlorate in four seawater samples collected from the region near harvest time were 30 {+-} 11 and 0.16 {+-} 0.084 {mu}g l{sup -1}, respectively. Concentrations of both iodide and perchlorate varied over a wide range for different seaweed species; iodide ranging from 16 to 3134 mg kg{sup -1} and perchlorate from 0.077 to 3.2 mg kg{sup -1}. The Laminaria species had the highest iodide concentration; Laminaria digitata is the seaweed species most commonly used in the kelp tablets sold in health food stores. Our sample of L. digitata contained 3134 {+-} 15 mg iodide/kg dry weight. The BCF varied widely for different species, with Laminaria species concentrating iodide preferentially over perchlorate. The iodide BCF (BCF{sub i}) to perchlorate BCF (BCF{sub p}) quotient ranged from 0.66 to 53; L. digitata and L. saccarina having a BCF{sub i}/BCF{sub p} value of 45 and 53, respectively, far

  12. Perchlorate in seawater

    International Nuclear Information System (INIS)

    Martinelango, P. Kalyani; Tian Kang; Dasgupta, Purnendu K.

    2006-01-01

    There has been no reliable published data on the presence of perchlorate in seawater. Seaweeds are among the most important plant life in the ocean and are good sources of iodine and have been widely used as food and nutritional supplement. Perchlorate is known to inhibit the transport of iodide by the sodium iodide symporter (NIS), present e.g., in the thyroid and mammary glands. With perchlorate being increasingly detected in drinking water, milk and various other foods, increasing the iodide intake through inexpensive natural supplements may be an attractive solution for maintaining iodine assimilation. We report here measurable concentrations of perchlorate in several samples of seawater (detectable in about half the samples analyzed). We also report the iodide and perchlorate concentrations of 11 different species of seaweed and the corresponding bioconcentration factors (BCF) for perchlorate and iodide, relative to the seawater from which they were harvested. All seaweed samples came from the same region, off the coast of Northeastern Maine. Concentrations of iodide and perchlorate in four seawater samples collected from the region near harvest time were 30 ± 11 and 0.16 ± 0.084 μg l -1 , respectively. Concentrations of both iodide and perchlorate varied over a wide range for different seaweed species; iodide ranging from 16 to 3134 mg kg -1 and perchlorate from 0.077 to 3.2 mg kg -1 . The Laminaria species had the highest iodide concentration; Laminaria digitata is the seaweed species most commonly used in the kelp tablets sold in health food stores. Our sample of L. digitata contained 3134 ± 15 mg iodide/kg dry weight. The BCF varied widely for different species, with Laminaria species concentrating iodide preferentially over perchlorate. The iodide BCF (BCF i ) to perchlorate BCF (BCF p ) quotient ranged from 0.66 to 53; L. digitata and L. saccarina having a BCF i /BCF p value of 45 and 53, respectively, far greater than a simple anion exchange process

  13. Corrosion in seawater systems

    International Nuclear Information System (INIS)

    Henrikson, S.

    1988-01-01

    Highly alloyed stainless steels have been exposed to natural chlorinated and chlorine-free seawater at 35 deg. C. Simulated tube-tubesheet joints, weld joints and galvanic couples with titanium, 90/10 CuNi and NiAl bronze were tested and evaluated for corrosion. The corrosion rates of various anode materials - zinc, aluminium and soft iron - were also determined. Finally the risk of hydrogen embrittlement of tubes of ferritic stainless steels and titanium as a consequence of cathodic protection was studied. An attempt was also made to explain the cracking mechanism of the ferritic steels by means of transmission electron microscopy. One important conclusion of the project is that chlorinated seawater is considerably more corrosive to stainless steels than chlorine-free water, whereas chlorination reduces the rate of galvanic corrosion of copper materials coupled to stainless steels. Hydrogen embrittlement of ferritic stainless steels and titanium as a consequence of cathodic protection of carbon steel or cast iron in the same structure can be avoided by strict potentiostatic control of the applied potential. (author)

  14. State of radionuclides in seawater. Comparison of natural stable and artificial radioactive isotope s of mercury and zinc in natural waters of the arid zone of the USSR

    International Nuclear Information System (INIS)

    Rakhmatov, U; Khikmatov, K; Kist, A.A.; Kulmatov, R.A.; Teshabaev, S.T.; Volkov, A.A.

    1986-01-01

    This paper studies the state of stable and artificial radioactive isotopes of merury and zinc in natural waters of the arid zone of the USSR by radioactivity and radiochemical methods. Convergent results have been obtained for the dissolved forms of mercury and zinc in natural waters of the arid zone in a comparison of the results of radioactivation analysis and laboratory simulation using the radionuclides mercury-203 and zinc-65

  15. Calcification in a marginal sea – influence of seawater [Ca2+] and carbonate chemistry on bivalve shell formation

    Directory of Open Access Journals (Sweden)

    J. Thomsen

    2018-03-01

    Full Text Available In estuarine coastal systems such as the Baltic Sea, mussels suffer from low salinity which limits their distribution. Anthropogenic climate change is expected to cause further desalination which will lead to local extinctions of mussels in the low saline areas. It is commonly accepted that mussel distribution is limited by osmotic stress. However, along the salinity gradient, environmental conditions for biomineralization are successively becoming more adverse as a result of reduced [Ca2+] and dissolved inorganic carbon (CT availability. In larvae, calcification is an essential process starting during early development with formation of the prodissoconch I (PD I shell, which is completed under optimal conditions within 2 days. Experimental manipulations of seawater [Ca2+] start to impair PD I formation in Mytilus larvae at concentrations below 3 mM, which corresponds to conditions present in the Baltic at salinities below 8 g kg−1. In addition, lowering dissolved inorganic carbon to critical concentrations (< 1 mM similarly affected PD I size, which was well correlated with calculated ΩAragonite and [Ca2+][HCO3−] ∕ [H+] in all treatments. Comparing results for larvae from the western Baltic with a population from the central Baltic revealed a significantly higher tolerance of PD I formation to lowered [Ca2+] and [Ca2+][HCO3−] ∕ [H+] in the low saline adapted population. This may result from genetic adaptation to the more adverse environmental conditions prevailing in the low saline areas of the Baltic. The combined effects of lowered [Ca2+] and adverse carbonate chemistry represent major limiting factors for bivalve calcification and can thereby contribute to distribution limits of mussels in the Baltic Sea.

  16. Calcification in a marginal sea - influence of seawater [Ca2+] and carbonate chemistry on bivalve shell formation

    Science.gov (United States)

    Thomsen, Jörn; Ramesh, Kirti; Sanders, Trystan; Bleich, Markus; Melzner, Frank

    2018-03-01

    In estuarine coastal systems such as the Baltic Sea, mussels suffer from low salinity which limits their distribution. Anthropogenic climate change is expected to cause further desalination which will lead to local extinctions of mussels in the low saline areas. It is commonly accepted that mussel distribution is limited by osmotic stress. However, along the salinity gradient, environmental conditions for biomineralization are successively becoming more adverse as a result of reduced [Ca2+] and dissolved inorganic carbon (CT) availability. In larvae, calcification is an essential process starting during early development with formation of the prodissoconch I (PD I) shell, which is completed under optimal conditions within 2 days. Experimental manipulations of seawater [Ca2+] start to impair PD I formation in Mytilus larvae at concentrations below 3 mM, which corresponds to conditions present in the Baltic at salinities below 8 g kg-1. In addition, lowering dissolved inorganic carbon to critical concentrations (< 1 mM) similarly affected PD I size, which was well correlated with calculated ΩAragonite and [Ca2+][HCO3-] / [H+] in all treatments. Comparing results for larvae from the western Baltic with a population from the central Baltic revealed a significantly higher tolerance of PD I formation to lowered [Ca2+] and [Ca2+][HCO3-] / [H+] in the low saline adapted population. This may result from genetic adaptation to the more adverse environmental conditions prevailing in the low saline areas of the Baltic. The combined effects of lowered [Ca2+] and adverse carbonate chemistry represent major limiting factors for bivalve calcification and can thereby contribute to distribution limits of mussels in the Baltic Sea.

  17. Influence of weather conditions on natural radioactivity

    International Nuclear Information System (INIS)

    Simion, Florin; Simion, Elena; Cuculeanu, Vasile; Mihalcea, Ion

    2011-01-01

    This paper presents the dependence of the natural radioactivity on atmospheric weather conditions: air temperature, atmospheric pressure, wind speed, atmospherical precipitations and relative humidity. The values used in the paper were taken from the environmental radioactivity monitoring in Botosani city, Romania, as measured by the Environmental Radioactivity Surveillance Station. Daily global measurements of atmospheric deposition beta and atmospheric aerosols as well were carried out, including the indirect determination of radon and thoron, and the absorbed gamma dose rate in air, as well. Sampling and measurement frequency depended on the type of sample analyzed as follows: atmospheric deposition were taken daily, atmospheric aerosols were collected 4 times/day, with a sampling interval of 5 hours while the air absorbed dose rate was determined at a hourly rate. The coefficient of multiple correlation between the type of analysis and weather conditions, was determined. By using multiple linear regression it was highlighted the natural radioactivity dependence on the atmospheric conditions and meteorological parameters by a mathematical expression that can be used to determine missing values in a time series of measured data. By predicting the measured values our procedure can be considered as a validation process of the measurement accuracy

  18. The influence of Desulfovibrio vulgaris on the efficiency of imidazoline as a corrosion inhibitor on low-carbon steel in seawater

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Rodriguez, Carlos A. [Facultad de Quimica UNAM, Ciudad Universitaria, C.P. 04510 Mexico, D.F. (Mexico)], E-mail: gorc74@yahoo.com; Rodriguez-Gomez, Francisco J.; Genesca-Llongueras, Joan [Facultad de Quimica UNAM, Ciudad Universitaria, C.P. 04510 Mexico, D.F. (Mexico)

    2008-12-01

    The action of Desulfovibrio vulgaris (Dv) during a corrosion process has been reported in literature, but the influence of imidazoline in the formation of biofilms is not clear, as well as the effect of bacteria on the efficiency of the corrosion inhibitors. The aim of this work is to determine the behavior of bacteria in the presence of imidazoline. Therefore, the growth of Dv, isolated and characterized from a morphological point of view, was monitored during 21 days, during which synthetic seawater was used as the culture medium, according to the ASTM D665-98 standard. Electrochemical noise (EN) was employed to establish the corrosion type generated by the microorganism on an AISI 1018 steel cylinder. The attack was observed using scanning electron microscopy (SEM). In order to evaluate the efficiency of the corrosion inhibitor, Tafel extrapolation was used; the optimum concentration of the inhibitor was used in the presence of sulphate-reducing bacteria (SRB). In general, two forms of corrosion were observed: localized corrosion (in the LAG phase) and mixed corrosion (in the LOG phase)

  19. The influence of Desulfovibrio vulgaris on the efficiency of imidazoline as a corrosion inhibitor on low-carbon steel in seawater

    International Nuclear Information System (INIS)

    Gonzalez-Rodriguez, Carlos A.; Rodriguez-Gomez, Francisco J.; Genesca-Llongueras, Joan

    2008-01-01

    The action of Desulfovibrio vulgaris (Dv) during a corrosion process has been reported in literature, but the influence of imidazoline in the formation of biofilms is not clear, as well as the effect of bacteria on the efficiency of the corrosion inhibitors. The aim of this work is to determine the behavior of bacteria in the presence of imidazoline. Therefore, the growth of Dv, isolated and characterized from a morphological point of view, was monitored during 21 days, during which synthetic seawater was used as the culture medium, according to the ASTM D665-98 standard. Electrochemical noise (EN) was employed to establish the corrosion type generated by the microorganism on an AISI 1018 steel cylinder. The attack was observed using scanning electron microscopy (SEM). In order to evaluate the efficiency of the corrosion inhibitor, Tafel extrapolation was used; the optimum concentration of the inhibitor was used in the presence of sulphate-reducing bacteria (SRB). In general, two forms of corrosion were observed: localized corrosion (in the LAG phase) and mixed corrosion (in the LOG phase)

  20. Use of Tritium and Helium to Define Groundwater Flow Conditions in a Coastal Aquifer Influenced by Seawater Intrusion: Everglades National Park

    Science.gov (United States)

    Price, R. M.; Top, Z.; Happell, J. D.; Swart, P. K.

    2002-05-01

    The concentrations of tritium (3H) and helium isotopes (3He, 4He) were used as tracers of groundwater flow in Everglades National Park, South Florida (USA). Both fresh and brackish groundwaters were collected from 47 wells completed at depths ranging from 2 m to 73 m within the Surficial Aquifer System (SAS). Ages as determined by 3H/3He techniques indicate that groundwater within the upper 28 m originated after the nuclear era (within the last 42 yr) and below 28 m before then with evidence of some mixing at the interface. Inter-annual variation of the 3H/3He ages within the upper 28 m was significant throughout the three year investigation, suggesting varying hydrologic conditions. The age of the shallow groundwater in the southern regions of ENP (Rocky Glades and Taylor Slough) tended to be younger following times of high water level when the dominant direction of groundwater flow water was to the southeast. In the same region, significantly older groundwater was observed following times of low water levels and a shift in the groundwater flow direction toward the southwest. Near the canals, the reverse occurred with the ages of shallow groundwater tending to be younger following times of low water levels, suggesting a greater influence of recharge water from the canals to the surrounding aquifer. Although water levels and the direction of hydrologic gradients vary greatly within a 3-month time period, the average age of the shallow (Aquifer suggesting a preferential flow path to the deeper formation. An increase in 4He with depth suggests that radiogenic 4He produced in the underlying Hawthorn Group is dispersed into the SAS. Higher Δ 4He values in brackish groundwaters compared to fresh waters from similar depths indicate an enhanced vertical transport of 4He in the seawater mixing zone. Seawater intrudes at distances of 6 to 28 km at shallow depths (Florida Bay and the Gulf of Mexico over an approximately 6 to 28 km wide strip that parallels the coastline.

  1. Development of pre-concentration procedure for the determination of Hg isotope ratios in seawater samples

    International Nuclear Information System (INIS)

    Štrok, Marko; Hintelmann, Holger; Dimock, Brian

    2014-01-01

    Highlights: • The method for the quantitative pre-concentration of Hg from seawater was developed. • First report of Hg isotope ratios in seawater is presented. • A unique mass independent 200 Hg isotope fractionation was observed. • This fractionation has unique potential to distinguish anthropogenic and natural Hg. - Abstract: Hg concentrations in seawater are usually too low to allow direct (without pre-concentration and removal of salt matrix) measurement of its isotope ratios with multicollector-inductively coupled plasma mass spectrometry (MC-ICP-MS). Therefore, a new method for the pre-concentration of Hg from large volumes of seawater was developed. The final method allows for relatively fast (about 2.5 L h −1 ) and quantitative pre-concentration of Hg from seawater samples with an average Hg recovery of 98 ± 6%. Using this newly developed method we determined Hg isotope ratios in seawater. Reference seawater samples were compared to samples potentially impacted by anthropogenic activity. The results show negative mass dependent fractionation relative to the NIST 3133 Hg standard with δ 202 Hg values in the range from −0.50‰ to −1.50‰. In addition, positive mass independent fractionation of 200 Hg was observed for samples from reference sites, while impacted sites did not show significant Δ 200 Hg values. Although the influence of the impacted sediments is limited to the seawater and particulate matter in very close proximity to the sediment, this observation may raise the possibility of using Δ 200 Hg to distinguish between samples from impacted and reference sites

  2. Atmospheric Aerosol Emissions Related to the Mediterranean Seawater Biogeochemistry

    Science.gov (United States)

    Sellegri, K.; Schwier, A.; Rose, C.; Gazeau, F. P. H.; Guieu, C.; D'anna, B.; Ebling, A. M.; Pey, J.; Marchand, N.; Charriere, B.; Sempéré, R.; Mas, S.

    2016-02-01

    Marine aerosols contribute significantly to the global aerosol load and consequently has an important impact on the Earth's climate. Different factors influence the way they are produced at the air/seawater interface. The sea state (whitecap coverage, temperature, etc. ) influence the size and concentration of primarily produced particles but also biogeochemical characteristics of the seawater influence both the physical and chemical primary fluxes to the atmosphere. An additional aerosol source of marine aerosol to the atmosphere is the formation of new particles by gaz-to-particle conversion, i.e. nucleation. How the seawater and surface microlayer biogeochemical compositions influences the aerosol emissions is still a large debate. In order to study marine emissions, one approach is to use semi-controlled environments such as mesocosms. Within the MedSea and SAM projects, we characterize the primary Sea Spray Aerosol (SSA) during mesocosms experiments performed during different seasons in the Mediteranean Sea. Mesocosms were either left unchanged as control or enriched by addition of nutriments in order to create different levels of phytoplanctonic activities. The mesocosms waters were daily analyzed for their chemical and biological composition (DOC, CDOM, TEP, Chl-a, virus, bacteria, phytoplankton and zooplankton concentrations). SSA production by bubble bursting was daily simulated in a dedicated set-up. The size segregated SSA number fluxes, cloud condensation nuclei (CCN) properties, and chemical composition were determined as a function of the seawater characteristics. We show that the SSA organic content was clearly correlated to the seawater Chl-a level, provided that the mesocosm was not enriched to create an artificial phytoplanctonic bloom. In our experiments, the enrichment of the seawater with natural surface microlayer did not impact the SSA organic content nor its CCN properties. At last, nucleation of secondary particles were observed to occur in

  3. Influence of Magnesium Ions in the Seawater Environment on the Improvement of the Corrosion Resistance of Low-Chromium-Alloy Steel.

    Science.gov (United States)

    Song, Sol-Ji; Kim, Jung-Gu

    2018-01-20

    This study examined the synergic effect of alloying the element Cr and the environmental element Mg 2+ ions on the corrosion property of a low-alloy steel in seawater at 60 °C, by means of electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) tests and weight-loss tests. The Mg 2+ ions in seawater played an important role in lowering the electron transfer of the rust layer in the Cr-containing steel. The corrosion resistance of the Cr-containing steel is superior to that of blank steel in Mg 2+ ions containing seawater. XPS and XRD results indicated that the formation of MgFe₂O₄ and a mixed layer (Cr oxide + FeCr₂O₄ + MgCr₂O₄) improved the corrosion resistance of the low-alloy steel in the seawater.

  4. Influence of Magnesium Ions in the Seawater Environment on the Improvement of the Corrosion Resistance of Low-Chromium-Alloy Steel

    Directory of Open Access Journals (Sweden)

    Sol-Ji Song

    2018-01-01

    Full Text Available This study examined the synergic effect of alloying the element Cr and the environmental element Mg2+ ions on the corrosion property of a low-alloy steel in seawater at 60 °C, by means of electrochemical impedance spectroscopy (EIS, linear polarization resistance (LPR tests and weight-loss tests. The Mg2+ ions in seawater played an important role in lowering the electron transfer of the rust layer in the Cr-containing steel. The corrosion resistance of the Cr-containing steel is superior to that of blank steel in Mg2+ ions containing seawater. XPS and XRD results indicated that the formation of MgFe2O4 and a mixed layer (Cr oxide + FeCr2O4 + MgCr2O4 improved the corrosion resistance of the low-alloy steel in the seawater.

  5. Seawater predesalination with electrodialysis

    NARCIS (Netherlands)

    Galama, A.H.; Saakes, M.; Bruning, H.; Rijnaarts, H.H.M.; Post, J.W.

    2014-01-01

    The suitability of ED for seawater desalination was investigated and we quantified the energy losses that play a role in electrodialysis. The combination of electrodialysis (ED) and brackish water reverse osmosis (BWRO) is presented as an alternative desalination strategy for seawater reverse

  6. Impact of seawater [Ca

    NARCIS (Netherlands)

    Mewes, A.; Langer, G.; Thoms, S.; Nehrke, G.; Reichart, G.J.; de Nooijer, L.J.; Bijma, J.

    2015-01-01

    Mg / Ca ratios in foraminiferal tests are routinely used as paleotemperature proxies, but on long timescales, they also hold the potential to reconstruct past seawater Mg / Ca. The impact of both temperature and seawater Mg / Ca on Mg incorporation in Foraminifera has been quantified by a number of

  7. Real-time corrosion monitoring of steel influenced by microbial activity (SRB) under controlled seawater injection conditions

    Energy Technology Data Exchange (ETDEWEB)

    Kane, Russell D. [InterCorr International, Inc., 14503 Bammel N. Houston Road, Suite 300, Houston, TX 77019 (United States); Campbell, Scott [Commercial Microbiology Inc., 10400 Westoffice Drive Suite 107, Houston, TX 77042 (United States)

    2004-07-01

    An experimental study of microbiologically influenced corrosion (MIC) was conducted involving online, real-time monitoring of a bio-film loop under controlled conditions simulating oil field water handling and injection. Bio-film growth, MIC and biocide efficacy were monitored using an automated, multi-technique monitoring system including linear polarization resistance, electrochemical noise and harmonic distortion analysis. This data was correlated with conventional off-line methods to differentiate conditions of varying MIC activity in real-time to facilitate quick assessment and operator intervention. (authors)

  8. Degradation of riverine dissolved organic matter by seawater bacteria

    NARCIS (Netherlands)

    Rochelle-Newall, E.J.; Pizay, M-D.; Middelburg, J.J.; Boschker, H.T.S.; Gattuso, J.P.

    2004-01-01

    The functional response of a seawater bacterial community transplanted into freshwater dissolved organic matter (DOM) was investigated together with the response of natural populations of bacteria to size-fractioned natural source water. Seawater bacteria were incubated over a period of 8 d in

  9. Butterfly valves for seawater

    International Nuclear Information System (INIS)

    Yamanaka, Katsuto

    1991-01-01

    Recently in thermal and nuclear power stations and chemical plants which have become large capacity, large quantity of cooling water is required, and mostly seawater is utilized. In these cooling water systems, considering thermal efficiency and economy, the pipings become complex, and various control functions are demanded. For the purpose, the installation of shut-off valves and control valves for pipings is necessary. The various types of valves have been employed, and in particular, butterfly valves have many merits in their function, size, structure, operation, maintenance, usable period, price and so on. The corrosion behavior of seawater is complicated due to the pollution of seawater, therefore, the environment of the valves used for seawater became severe. The structure and the features of the butterfly valves for seawater, the change of the structure of the butterfly valves for seawater and the checkup of the butterfly valves for seawater are reported. The corrosion of metallic materials is complicatedly different due to the locating condition of plants, the state of pipings and the condition of use. The corrosion countermeasures for butterfly valves must be examined from the synthetic viewpoints. (K.I.)

  10. Improving the ecological relevance of toxicity tests on scleractinian corals: Influence of season, life stage, and seawater temperature

    Science.gov (United States)

    Hedouin, Laetitia; Wolf, Ruth E.; Phillips, Jeff; Gates, Ruth D.

    2016-01-01

    Metal pollutants in marine systems are broadly acknowledged as deleterious: however, very little data exist for tropical scleractinian corals. We address this gap by investigating how life-history stage, season and thermal stress influence the toxicity of copper (Cu) and lead (Pb) in the coral Pocillopora damicornis. Our results show that under ambient temperature, adults and larvae appear to tolerate exposure to unusually high levels of copper (96 h-LC50 ranging from 167 to 251 μg Cu L−1) and lead (from 477 to 742 μg Pb L−1). Our work also highlights that warmer conditions (seasonal and experimentally manipulated) reduce the tolerance of adults and larvae to Cu toxicity. Despite a similar trend observed for the response of larvae to Pb toxicity to experimentally induced increase in temperature, surprisingly adults were more resistant in warmer condition to Pb toxicity. In the summer adults were less resistant to Cu toxicity (96 h-LC50 = 175 μg L−1) than in the winter (251 μg L−1). An opposite trend was observed for the Pb toxicity on adults between summer and winter (96 h-LC50 of 742 vs 471 μg L−1, respectively). Larvae displayed a slightly higher sensitivity to Cu and Pb than adults. An experimentally induced 3 °C increase in temperature above ambient decreased larval resistance to Cu and Pb toxicity by 23–30% (96 h-LC50 of 167 vs 129 μg Cu L−1 and 681 vs 462 μg Pb L−1).

  11. Influence of sulfate-reducing bacteria on the corrosion of steel in seawater: laboratory and in situ study

    International Nuclear Information System (INIS)

    Benbouzid-Rollet, N.

    1993-01-01

    A fouling reactor was designed to study, the influence of a mixed bio-film on AISI 316 L stainless steel. The bio-film was formed on the steel surface by the fermentative bacterium Vibrio natriegens. The sulfate-reducing bacterium Desulfovibrio vulgaris was then introduced in the reactor and colonized the surface, constituting approximately 5 % of the total population. The settlement of an anaerobic bacterium in the bio-film shows in it the existence of anaerobic micro-niches. Stainless steel electrochemical behavior was analyzed using open circuit potential and potentiodynamic polarization curves. Growth of the bio-film does not induce corrosion, but seems to change the cathodic oxygen reduction kinetics, diminishing the corrosion hazard. This effect increases when D. vulgaris grows in the bio-film. An ennobling of the open circuit potential was observed, similar to field cases already described. A case of drilling corrosion of carbon steel in a harbour area showed the characteristics of anaerobic corrosion related to sulfate-reducing bacteria. The total cultivatable SRB population was quantified and metabolic types were enumerated using specific electron donors. A maximum cell density of 1,1 x 10 8 cells/ cm 2 was estimated, revealing a very important growth of SRB on surfaces. Population structure was different in corroded and non-corroded areas. In corroded area, SRB utilizing benzoate and propionate were more abundant. A strain belonging to the sporulating genus Desulfotomaculum was isolated using these substrates, suggesting a partial aeration in the area of hole appearance. However, in vitro corrosion assays showed that the bacterial population sampled in this area induced a consequent weight loss of steel coupons, in the absence of oxygen. This was observed only with a diversified population, similar to that present in situ. It could not be reproduced with a mixed culture of two purified strains. (author)

  12. SRB seawater corrosion project

    Science.gov (United States)

    Bozack, M. J.

    1991-01-01

    The corrosion behavior of 2219 aluminum when exposed to seawater was characterized. Controlled corrosion experiments at three different temperatures (30, 60 and 100 C) and two different environments (seawater and 3.5 percent salt solution) were designed to elucidate the initial stages in the corrosion process. It was found that 2219 aluminum is an active catalytic surface for growth of Al2O3, NaCl, and MgO. Formation of Al2O3 is favored at lower temperatures, while MgO is favored at higher temperatures. Visible corrosion products are formed within 30 minutes after seawater exposure. Corrosion characteristics in 3.5 percent salt solution are different than corrosion in seawater. Techniques utilized were: (1) scanning electron microscopy, (2) energy dispersive x-ray spectroscopy, and (3) Auger electron spectroscopy.

  13. Uranium from seawater

    International Nuclear Information System (INIS)

    Gregg, D.; Folkendt, M.

    1982-01-01

    A novel process for recovering uranium from seawater is proposed and some of the critical technical parameters are evaluated. The process, in summary, consists of two different options for contacting adsorbant pellets with seawater without pumping the seawater. It is expected that this will reduce the mass handling requirements, compared to pumped seawater systems, by a factor of approximately 10 5 , which should also result in a large reduction in initial capital investment. Activated carbon, possibly in combination with a small amount of dissolved titanium hydroxide, is expected to be the preferred adsorbant material instead of the commonly assumed titanium hydroxide alone. The activated carbon, after exposure to seawater, can be stripped of uranium with an appropriate eluant (probably an acid) or can be burned for its heating value (possible in a power plant) leaving the uranium further enriched in its ash. The uranium, representing about 1% of the ash, is then a rich ore and would be recovered in a conventional manner. Experimental results have indicated that activated carbon, acting alone, is not adequately effective in adsorbing the uranium from seawater. We measured partition coefficients (concentration ratios) of approximately 10 3 in seawater instead of the reported values of 10 5 . However, preliminary tests carried out in fresh water show considerable promise for an extraction system that uses a combination of dissolved titanium hydroxide (in minute amounts) which forms an insoluble compound with the uranyl ion, and the insoluble compound then being sorbed out on activated carbon. Such a system showed partition coefficients in excess of 10 5 in fresh water. However, the system was not tested in seawater

  14. The role of humic and fulvic acids in the phototransformation of phenolic compounds in seawater

    International Nuclear Information System (INIS)

    Calza, P.; Vione, D.; Minero, C.

    2014-01-01

    Humic substances (HS) are known to act as photosensitizers toward the transformation of pollutants in the surface layer of natural waters. This study focused on the role played by HS toward the transformation of xenobiotics in seawater, with the purpose of assessing the prevailing degradation routes. Phenol was chosen as model xenobiotic and its transformation was investigated under simulated sunlight in the presence of terrestrial or marine humic and fulvic acids, in pure water at pH 8, artificial seawater (ASW) or natural seawater (NSW). The following parameters were determined: (1) the phenol degradation rate; (2) the variation in HS concentration with irradiation time; (3) the production of transformation products; (4) the influence of iron species on the transformation process. Faster transformation of phenol was observed with humic acids (HA) compared to fulvic acids (SRFA), and transformation induced by both HA and SRFA was faster in ASW than that in pure water. These observations can be explained by assuming an interplay between different competing and sometimes opposite processes, including the competition between chloride, bromide and dissolved oxygen for reaction with HS triplet states. The analysis of intermediates formed in the different matrices under study showed the formation of several hydroxylated (hydroquinone, 1,4-benzoquinone, resorcinol) and condensed compounds (2,2′-bisphenol, 4,4′-bisphenol, 4-phenoxyphenol). Although 1,4-benzoquinone was the main transformation product, formation of condensed molecules was significant with both HA and SRFA. Experiments on natural seawater spiked with HS confirmed the favored formation of condensed products, suggesting a key role of humic matter in dimerization reactions occurring in saline water. - Highlights: • Phenol transformation in seawater can be photosensitized by humic substances. • Dimeric species are peculiar intermediates formed in the process. • Phenol degradation occurred faster with

  15. The role of humic and fulvic acids in the phototransformation of phenolic compounds in seawater

    Energy Technology Data Exchange (ETDEWEB)

    Calza, P., E-mail: paola.calza@unito.it; Vione, D.; Minero, C.

    2014-09-15

    Humic substances (HS) are known to act as photosensitizers toward the transformation of pollutants in the surface layer of natural waters. This study focused on the role played by HS toward the transformation of xenobiotics in seawater, with the purpose of assessing the prevailing degradation routes. Phenol was chosen as model xenobiotic and its transformation was investigated under simulated sunlight in the presence of terrestrial or marine humic and fulvic acids, in pure water at pH 8, artificial seawater (ASW) or natural seawater (NSW). The following parameters were determined: (1) the phenol degradation rate; (2) the variation in HS concentration with irradiation time; (3) the production of transformation products; (4) the influence of iron species on the transformation process. Faster transformation of phenol was observed with humic acids (HA) compared to fulvic acids (SRFA), and transformation induced by both HA and SRFA was faster in ASW than that in pure water. These observations can be explained by assuming an interplay between different competing and sometimes opposite processes, including the competition between chloride, bromide and dissolved oxygen for reaction with HS triplet states. The analysis of intermediates formed in the different matrices under study showed the formation of several hydroxylated (hydroquinone, 1,4-benzoquinone, resorcinol) and condensed compounds (2,2′-bisphenol, 4,4′-bisphenol, 4-phenoxyphenol). Although 1,4-benzoquinone was the main transformation product, formation of condensed molecules was significant with both HA and SRFA. Experiments on natural seawater spiked with HS confirmed the favored formation of condensed products, suggesting a key role of humic matter in dimerization reactions occurring in saline water. - Highlights: • Phenol transformation in seawater can be photosensitized by humic substances. • Dimeric species are peculiar intermediates formed in the process. • Phenol degradation occurred faster with

  16. Corrosion and Protection of Metal in the Seawater Desalination

    Science.gov (United States)

    Hou, Xiangyu; Gao, Lili; Cui, Zhendong; Yin, Jianhua

    2018-01-01

    Seawater desalination develops rapid for it can solve water scarcity efficiently. However, corrosion problem in the seawater desalination system is more serious than that in normal water. So, it is important to pay attention to the corrosion and protection of metal in seawater desalination. The corrosion characteristics and corrosion types of metal in the seawater desalination system are introduced in this paper; In addition, corrosion protect methods and main influencing factors are stated, the latest new technologies about anti-corrosion with quantum energy assisted and magnetic inhibitor are presented.

  17. Investigation of adsorbers for the extracting of uranium from seawater

    International Nuclear Information System (INIS)

    Witte, E.G.; Astheimer, L.; Schenk, H.J.; Schwochau, K.

    1979-01-01

    Organic ion exchangers have been tested with respect to their efficiency uranium from seawater. A complexing polymer resin which combines fast uptake of uranium with high selectivity is found to be able to accumulate uranium from natural seawater by a factor of 2.6 x 10 5 . (orig.) 891 HK/orig. 892 MKO [de

  18. INFLUENCE OF GREAT HYDRAULIC WORKS UPON NATURE AND MANKIND

    Directory of Open Access Journals (Sweden)

    Mircea O. POPOVICIU

    2011-11-01

    Full Text Available The great hydraulic works represent heavy environmental modifications and influence both humans (during the construction and the utilization and nature. The present paper compares these influences for two such works the Suez Canal and the Panama Canal. Both are relatively recent, have the same purpose (the increase of the East-West trade and were initiated by Ferdinand de Lesseps. The possibility of realization was analyzed long time before the beginning of the work. Both works are sources of huge incomes and created endless disputes between the great powers. The forecast level increase of the planetary ocean will affect differently these works.

  19. Do changes in natural gas futures prices influence changes in natural gas spot prices?

    International Nuclear Information System (INIS)

    Herbert, J.H.

    1993-01-01

    Data on natural gas futures and spot markets are examined to determine if variability in price on futures markets influences variability in price on spot markets. Using econometric techniques, it is found that changes in futures contract prices do not precede changes in spot market prices. (Author)

  20. Radiolytic removal of trihalomethane in chlorinated seawater

    International Nuclear Information System (INIS)

    Rajamohan, R.; Rajesh, Puspalata; Venugopalan, V.P.; Rangarajan, S.; Natesan, Usha

    2015-01-01

    Biofouling is one of the major operational problems in seawater cooling systems. It is controlled by application of chlorine based biocides in the range of 0.5-2.0 mg L -1 . The bromide in seawater reacts with the added chlorine and forms hypobromous acid. The brominated residual biocides react with natural organic matter present in the seawater, resulting in the formation of trihalomethanes (THM) such as bromoform (CHBr 3 ), dibromochloromethane (CHBr 2 Cl) bromodichloromethane (CHBrCl 2 ). Though THMs represent a small fraction of the added chlorine, they are relatively more persistent than residual chlorine, and hence pose a potential hazard to marine life because of their reported mutagenicity. There have been few reports on removal of THMs from chlorinated seawater. In this work, the efficacy of gamma irradiation technique for the removal of THMs from chlorine-dosed seawater was investigated. Experiments were carried out using seawater collected from Kalpakkam. Irradiation study was conducted in chlorinated (1, 3, and 5 mg L -1 of Cl 2 ) seawater by applying various dosages (0.4-5.0 kGy) of gamma radiation using a 60 Co Gamma Chamber 5000. Bromoform showed a faster rate of degradation as compared to other halocarbons like bromodichloromethane and dibromochloromethane. This shows the change in total THM concentration with variation in the radiation dose and initial Cl 2 dosing. When the percentage degradation of all the three trihalomethane species was compared with applied doses, it was found that the maximum reduction occurred at a dose of 2.5 kGy. The reduction was almost similar for all the three doses (1, 3, 5 ppm of Cl 2 ) used for chlorination. With a further increase in radiation dose to 5.0 kGy, a slight increase in reduction was observed

  1. Technical note: Examining ozone deposition over seawater

    Science.gov (United States)

    Surface layer resistance plays an important role in determining ozone deposition velocity over sea-water and can be influenced by chemical interactions at the air-water interface. Here, we examine the effect of chemical interactions of iodide, dimethylsulfide, dissolved organic c...

  2. Modification of Optical Properties of Seawater Exposed to Oil Contaminants Based on Excitation-Emission Spectra

    Science.gov (United States)

    Baszanowska, E.; Otremba, Z.

    2015-10-01

    The optical behaviour of seawater exposed to a residual amount of oil pollution is presented and a comparison of the fluorescence spectra of oil dissolved in both n-hexane and seawater is discussed based on excitation-emission spectra. Crude oil extracted from the southern part of the Baltic Sea was used to characterise petroleum properties after contact with seawater. The wavelength-independent fluorescence maximum for natural seawater and seawater artificially polluted with oil were determined. Moreover, the specific excitation-emission peaks for natural seawater and polluted water were analysed to identify the natural organic matter composition. It was found that fluorescence spectra identification is a promising method to detect even an extremely low concentration of petroleum residues directly in the seawater. In addition, alien substances disturbing the fluorescence signatures of natural organic substances in a marine environment is also discussed.

  3. The extent of the influence and flux estimation of volatile mercury from the aeration pool in a typical coal-fired power plant equipped with a seawater flue gas desulfurization system

    International Nuclear Information System (INIS)

    Sun, Lumin; Feng, Lifeng; Yuan, Dongxing; Lin, Shanshan; Huang, Shuyuan; Gao, Liangming; Zhu, Yong

    2013-01-01

    Before being discharged, the waste seawater from the flue gas desulfurization system of coal-fired power plants contains a large amount of mercury, and is treated in aeration pools. During this aeration process, part of the mercury enters the atmosphere, but only very limited impact studies concerning this have been carried out. Taking a typical Xiamen power plant as an example, the present study targeted the elemental mercury emitted from the aeration pool. Concentrations of dissolved gaseous mercury as high as 1.14 ± 0.17 ng·L −1 were observed in the surface waste seawater in the aeration pool, and gaseous elemental mercury (GEM) as high as 10.94 ± 1.89 ng·m −3 was found in the air above the pool. To investigate the area affected by this GEM through air transfer, the total mercury in the dust and topsoil samples around the aeration pool were analyzed. Much higher values were found compared to those at a reference site. Environmental factors other than solar radiation had limited influence on the concentrations of the mercury species in the pool. A simulation device was built in our laboratory to study the flux of mercury from the aeration pool into the air. The results showed that more than 0.59 kg of mercury was released from the aeration pool every year, occupying 0.3% of the total mercury in the waste seawater. The transfer of mercury from water to air during the aeration pool and its environmental influence should not be ignored. - Highlights: ► High concentration of volatile mercury was observed in the aeration pool. ► More than 0.3% of total discharged Hg emitted from the pool into the air. ► Higher aeration rate resulted in more mercury emitted into the air. ► The dust and topsoil around the pool were polluted with the mercury

  4. Natural selection on floral morphology can be influenced by climate.

    Science.gov (United States)

    Campbell, Diane R; Powers, John M

    2015-06-07

    Climate has the potential to influence evolution, but how it influences the strength or direction of natural selection is largely unknown. We quantified the strength of selection on four floral traits of the subalpine herb Ipomopsis sp. in 10 years that differed in precipitation, causing extreme temporal variation in the date of snowmelt in the Colorado Rocky Mountains. The chosen floral traits were under selection by hummingbird and hawkmoth pollinators, with hawkmoth abundance highly variable across years. Selection for flower length showed environmental sensitivity, with stronger selection in years with later snowmelt, as higher water resources can allow translation of pollination success into fitness based on seed production. Selection on corolla width also varied across years, favouring narrower corolla tubes in two unusual years with hawkmoths, and wider corollas in another late snowmelt year. Our results illustrate how changes in climate could alter natural selection even when the primary selective agent is not directly influenced. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  5. Recovery of lithium from seawater

    International Nuclear Information System (INIS)

    Ooi, Kenta; Miyai, Yoshitaka; Katoh, Shunsaku; Abe, Mitsuo.

    1989-01-01

    Lithium has been used for air conditioners, aluminum refining, ceramics, organic metal compounds, batteries and many other uses. Besides, attention is paid as the aluminum-lithium alloys as aircraft materials, and the raw materials for large capacity batteries and nuclear fusion reactors for the future. The amount of lithium resources has been estimated as 14 million tons, and is relatively abundant, but when the future increase of demand is considered, it is not necessarily sufficient. Japan lacks lithium resources, and the stable ensuring of the resources has become an important problem. Seawater contains lithium by 170 μg/l, and its total amount reaches 230 billion tons. The process of recovering lithium from seawater, geothermal water and natural gas brine has been actively researched since 10 years ago centering around Japan. At present, the search for the adsorbent that effectively collects lithium is the main subject. Also the recovery by coprecipitation has been investigated basically. The inorganic adsorbent for lithium is classified into aluminum type, compound antimonic acid type, layered compound type, ion sieve oxide type and others. Their lithium adsorption performance and adsorption mechanism are different remarkably, therefore, these of each group are described. (K.I.) 70 refs

  6. An Evaluation of Carbon Steel Corrosion Under Stagnant Seawater Conditions

    National Research Council Canada - National Science Library

    Lee, Jason

    2004-01-01

    Corrosion, of 1020 carbon steel coupons in, natural seawater over a six-month period was more aggressive under stagnant anaerobic conditions than stagnant aerobic conditions as measured by weight loss...

  7. Negative response of photosynthesis to natural and projected high seawater temperatures estimated by pulse amplitude modulation fluorometry in a temperate coral.

    Science.gov (United States)

    Caroselli, Erik; Falini, Giuseppe; Goffredo, Stefano; Dubinsky, Zvy; Levy, Oren

    2015-01-01

    Balanophyllia europaea is a shallow water solitary zooxanthellate coral, endemic to the Mediterranean Sea. Extensive field studies across a latitudinal temperature gradient highlight detrimental effects of rising temperatures on its growth, demography, and skeletal characteristics, suggesting that depression of photosynthesis at high temperatures might cause these negative effects. Here we test this hypothesis by analyzing, by means of pulse amplitude modulation fluorometry, the photosynthetic efficiency of B. europaea specimens exposed in aquaria to the annual range of temperatures experienced in the field (13, 18, and 28°C), and two extreme temperatures expected for 2100 as a consequence of global warming (29 and 32°C). The indicators of photosynthetic performance analyzed (maximum and effective quantum yield) showed that maximum efficiency was reached at 20.0-21.6°C, slightly higher than the annual mean temperature in the field (18°C). Photosynthetic efficiency decreased from 20.0 to 13°C and even more strongly from 21.6 to 32°C. An unusual form of bleaching was observed, with a maximum zooxanthellae density at 18°C that strongly decreased from 18 to 32°C. Chlorophyll a concentration per zooxanthellae cell showed an opposite trend as it was minimal at 18°C and increased from 18 to 32°C. Since the areal chlorophyll concentration is the product of the zooxanthellae density and its cellular content, these trends resulted in a homogeneous chlorophyll concentration per coral surface across temperature treatments. This confirms that B. europaea photosynthesis is progressively depressed at temperatures >21.6°C, supporting previous hypotheses raised by the studies on growth and demography of this species. This study also confirms the threats posed to this species by the ongoing seawater warming.

  8. Negative response of photosynthesis to natural and projected high seawater temperatures estimated by pulse amplitude modulation fluorometry in a temperate coral

    Directory of Open Access Journals (Sweden)

    Erik eCaroselli

    2015-11-01

    Full Text Available Balanophyllia europaea is a shallow water solitary zooxanthellate coral, endemic to the Mediterranean Sea. Extensive field studies across a latitudinal temperature gradient highlight detrimental effects of rising temperatures on its growth, demography and skeletal characteristics, suggesting that depression of photosynthesis at high temperatures might cause these negative effects. Here we test this hypothesis by analyzing, by means of pulse amplitude modulation fluorometry, the photosynthetic efficiency of B. europaea specimens exposed in aquaria to the annual range of temperatures experienced in the field (13°C, 18°C, and 28°C, and two extreme temperatures expected for 2100 as a consequence of global warming (29°C and 32°C. The indicators of photosynthetic performance analyzed (maximum and effective quantum yield showed that maximum efficiency was reached at 20.0-21.6°C, slightly higher than the annual mean temperature in the field (18°C. Photosynthetic efficiency decreased from 20.0°C to 13°C and even more strongly from 21.6°C to 32°C. An unusual form of bleaching was observed, with a maximum zooxanthellae density at 18°C that strongly decreased from 18°C to 32°C. Chlorophyll a concentration per zooxanthellae cell showed an opposite trend as it was minimal at 18°C and increased from 18°C to 32°C. Since the areal chlorophyll concentration is the product of the zooxanthellae density and its cellular content, these trends resulted in a homogeneous chlorophyll concentration per coral surface across temperature treatments. This confirms that B. europaea photosynthesis is progressively depressed at temperatures >21.6°C, supporting previous hypotheses raised by the studies on growth and demography of this species. This study also confirms the threats posed to this species by the ongoing seawater warming.

  9. Hydraulic conductivity of some bentonites in artificial seawater

    International Nuclear Information System (INIS)

    Komine, Hideo; Murakami, Satoshi; Yasuhara, Kazuya

    2011-01-01

    A high-level radioactive waste disposal facility might be built in a coastal area in Japan from the viewpoint of feasible transportation of waste. Therefore, it is important to investigate the effects of seawater on a bentonite-based buffer. This study investigated the influence of seawater on hydraulic conductivity of three common sodium-types of bentonite and one calcium-type bentonite by the laboratory experiments. >From the results of laboratory experiment, this study discussed the influence of seawater on hydraulic conductivity of bentonites from the viewpoints of kinds of bentonite such as exchangeable-cation type and montmorillonite content and dry density of bentonite-based buffer. (author)

  10. Nucleation from seawater emissions during mesocosm experiments

    Science.gov (United States)

    Rose, Clémence; Culot, Anais; Pey, Jorge; Schwier, Allison; Mas, Sébastien; Charriere, Bruno; Sempéré, Richard; Marchand, Nicolas; D'Anna, Barbara; Sellegri, Karine

    2015-04-01

    Nucleation and new particle formation in the marine atmosphere is usually associated to the presence of macroalgea emerged at low tides in coastal areas, while these processes were very rarely detected away from coastlines. In the present study, we evidence the formation of new particles from the 1 nm size above the seawater surface in the absence of any macroalgea population. Within the SAM project (Sources of marine Aerosol in the Mediterranean),seawater mesocosms experiments were deployed in May 2013 at the STARESO in western Corsica, with the goal of investigating the relationship between marine aerosol emissions and the seawater biogeochemical properties. Three mesocosms imprisoned 3,3 m3 of seawater each and their emerged part was flushed with aerosol-filtered natural air. One of these mesocosms was left unchanged as control and the two others were enriched by addition of nitrates and phosphates respecting Redfield ratio (N:P = 16) in order to create different levels of phytoplanctonic activities. We followed both water and air characteristics of three mesocosms during a period of three weeks by using online water and atmospheric probes as well as seawater daily samples for chemical and biological analysis. Secondary new particle formation was followed on-line in the emerged parts of the mesocosms, using a SMPS for the size distribution above 6 nm and a Particle Size Magnifyer (PSM) for the number of cluster particles between 1 and 6 nm. We will present how the cluster formation rates and early growth rates relate to the gaz-phase emissions from the seawater and to its biogeochemical properties. Aknowledgemnts: The authors want to acknowledge the financial support of the ANR "Source of marine Aerosol in the Mediterranean" (SAM), and the support of MISTRAL CHARMEX and MERMEX programs.

  11. Uranium from seawater

    International Nuclear Information System (INIS)

    1974-12-01

    The report concerns the possibilities of extracting uranium from seawater using either 'tidal' and 'pumped' schemes. It was decided to undertake an initial exercise on the pumped scheme. It was to take into account not only the direct energy requirements, but also the indirect energy inputs needed to produce the capital equipment, operating materials, etc. The report begins with a discussion of the technique of energy accounting, and the merits and limitations of the two principal approaches are compared. These are: 'Process Analysis' (or 'Energy Cost of Materials') and 'Input-Output Analysis' (or 'Energy Cost of Money'). A comparison is made between the energy cost of the tidal and pumped schemes, by both methods of analysis. A 'Best Estimate' is compiled calling on both methods, and this indicates that on an energy cost basis the pumped scheme is three times as expensive as the tidal scheme. Intermediate schemes are feasible, however. There is some evidence that the energy cost of an ore refining process with an initial concentration of 0.007% would be of the same order as that of the pumped seawater scheme. The energy cost of generating electricity using seawater uranium in an SGHWR is compared with the present UK generating system as a whole. (U.K.)

  12. Proteolytic enzymes in seawater: contribution of prokaryotes and protists

    Science.gov (United States)

    Obayashi, Y.; Suzuki, S.

    2016-02-01

    Proteolytic enzyme is one of the major catalysts of microbial processing of organic matter in biogeochemical cycle. Here we summarize some of our studies about proteases in seawater, including 1) distribution of protease activities in coastal and oceanic seawater, 2) responses of microbial community and protease activities in seawater to organic matter amending, and 3) possible contribution of heterotrophic protists besides prokaryotes to proteases in seawater, to clarify cleared facts and remaining questions. Activities of aminopeptidases, trypsin-type and chymotrypsin-type proteases were detected from both coastal and oceanic seawater by using MCA-substrate assay. Significant activities were detected from not only particulate (cell-associated) fraction but also dissolved fraction of seawater, especially for trypsin-type and chymotrypsin-type proteases. Hydrolytic enzymes in seawater have been commonly thought to be mainly derived from heterotrophic prokaryotes; however, it was difficult to determine actual source organisms of dissolved enzymes in natural seawater. Our experiment with addition of dissolved protein to subtropical oligotrophic Pacific water showed drastically enhancement of the protease activities especially aminopeptidases in seawater, and the prokaryotic community structure simultaneously changed to be dominant of Bacteroidetes, indicating that heterotrophic bacteria were actually one of the sources of proteases in seawater. Another microcosm experiment with free-living marine heterotrophic ciliate Paranophrys marina together with an associated bacterium showed that extracellular trypsin-type activity was mainly attributed to the ciliate. The protist seemed to work in organic matter digestion in addition to be a grazer. From the results, we propose a system of organic matter digestion by prokaryotes and protists in aquatic environments, although their actual contribution in natural environments should be estimated in future studies.

  13. Removal of tributyltin from contaminated seawater by combinations of photolytic and TiO2 mediated photocatalytic processes

    DEFF Research Database (Denmark)

    Muff, Jens; Simonsen, Morten Enggrob; Søgaard, Erik Gydesen

    2017-01-01

    Harbour sediment contaminated with tributyltin (TBT) is a worldwide problem and treatment of TBT contaminated seawater is an issue during dredging operations. This study presents results from photolytic and photocatalytic treatment experiments where the influence of the seawater matrix, different...

  14. Emotional faces influence evaluation of natural and transformed food.

    Science.gov (United States)

    Manippa, Valerio; Padulo, Caterina; Brancucci, Alfredo

    2018-07-01

    Previous evidence showed the presence of a straight relationship between feeding behavior and emotions. Despite that, no studies have focused on the influence of emotional faces on food processing. In our study, participants were presented with 72 couples of visual stimuli composed of a neutral, happy, or disgusted faces (5000 ms duration in Experiment 1, adaptation; 150 ms in Experiment 2, priming) followed by a food stimulus (1500 ms). Food stimuli were grouped in pleasant foods, further divided in natural and transformed, and unpleasant rotten foods. The task consisted in judging the food valence (as 'pleasant' or 'unpleasant') by keypress. Results showed a different pattern of response based on the transformation level of food. In general, the evaluation of natural foods was more rapid compared with transformed foods, maybe for their simplicity and healthier perception. In addition, transformed foods yielded incongruent responses with respect to the preceding emotional face, whereas natural foods yielded congruent responses with respect to it. These effects were independent of the duration of the emotional face (i.e., adaptation or priming paradigm) and may depend on pleasant food stimuli salience.

  15. Investigating the Crevice Corrosion Behavior of Coated Stainless Steel in Seawater

    National Research Council Canada - National Science Library

    Kain, Robert

    2000-01-01

    .... austenitic stainless steel. Testing in natural seawater has demonstrated that coatings can protect susceptible stainless steel from barnacle related crevice corrosion and localized corrosion at weldments...

  16. Past seawater experience enhances seawater adaptability in medaka, Oryzias latipes.

    Science.gov (United States)

    Miyanishi, Hiroshi; Inokuchi, Mayu; Nobata, Shigenori; Kaneko, Toyoji

    2016-01-01

    During the course of evolution, fishes have acquired adaptability to various salinity environments, and acquirement of seawater (SW) adaptability has played important roles in fish evolution and diversity. However, little is known about how saline environments influence the acquirement of SW adaptability. The Japanese medaka Oryzias latipes is a euryhaline species that usually inhabits freshwater (FW), but is also adaptable to full-strength SW when transferred through diluted SW. In the present study, we examined how past SW experience affects hyposmoregulatory ability in Japanese medaka. For the preparation of SW-experienced fish, FW medaka were acclimated to SW after pre-acclimation to 1/2 SW, and the SW-acclimated fish were transferred back to FW. The SW-experienced fish and control FW fish (SW-inexperienced fish) were transferred directly to SW. Whereas control FW fish did not survive direct transfer to SW, 1/4 of SW-experienced fish adapted successfully to SW. Although there were no significant differences in blood osmolality and plasma Na(+) and Cl(-) concentrations between SW-experienced and control FW medaka in FW, increments in these parameters following SW transfer were lower in SW-experienced fish than in control FW fish. The gene expression of SW-type Na(+), K(+)-ATPase (NKA) in the gills of SW-experienced medaka increased more quickly after direct SW transfer compared with the expression in control FW fish. Prior to SW transfer, the density of NKA-immunoreactive ionocytes in the gills was higher in SW-experienced fish than in control FW fish. Ionocytes expressing CFTR Cl(-) channel at the apical membrane and those forming multicellular complexes, both of which were characteristic of SW-type ionocytes, were also increased in SW-experienced fish. These results indicate that past SW experience enhances the capacity of Na(+) and Cl(-) secretion in ionocytes and thus hypoosmoregulatory ability of Japanese medaka, suggesting the presence of epigenetic

  17. The influence of color on emotional perception of natural scenes.

    Science.gov (United States)

    Codispoti, Maurizio; De Cesarei, Andrea; Ferrari, Vera

    2012-01-01

    Is color a critical factor when processing the emotional content of natural scenes? Under challenging perceptual conditions, such as when pictures are briefly presented, color might facilitate scene segmentation and/or function as a semantic cue via association with scene-relevant concepts (e.g., red and blood/injury). To clarify the influence of color on affective picture perception, we compared the late positive potentials (LPP) to color versus grayscale pictures, presented for very brief (24 ms) and longer (6 s) exposure durations. Results indicated that removing color information had no effect on the affective modulation of the LPP, regardless of exposure duration. These findings imply that the recognition of the emotional content of scenes, even when presented very briefly, does not critically rely on color information. Copyright © 2011 Society for Psychophysiological Research.

  18. Seawater and marine sidements

    International Nuclear Information System (INIS)

    Eicke, H.F.

    1985-01-01

    The Deutsches Hydrographisches Institut (DHI) is responsible for monitoring the radioactive substances (such as Cs-137, Cs-134, Sr-90, H-3, Pu-239, Pu-240) in the seawater and marine sediments along the Federal German seacoasts, of the fishing grounds of the Federal German offshore fishery industry, and of marine currents moving towards these fishing grounds. The DHI has been carrying out this task since 1965, activities being placed under the responsibility of the DHI Department for Marine Radioactivity, which since 1960 is a directing centre within the Government's system for environmental radioactivity monitoring. (orig./DG) [de

  19. The Influence of Familiarity on Affective Responses to Natural Scenes

    Science.gov (United States)

    Sanabria Z., Jorge C.; Cho, Youngil; Yamanaka, Toshimasa

    This kansei study explored how familiarity with image-word combinations influences affective states. Stimuli were obtained from Japanese print advertisements (ads), and consisted of images (e.g., natural-scene backgrounds) and their corresponding headlines (advertising copy). Initially, a group of subjects evaluated their level of familiarity with images and headlines independently, and stimuli were filtered based on the results. In the main experiment, a different group of subjects rated their pleasure and arousal to, and familiarity with, image-headline combinations. The Self-Assessment Manikin (SAM) scale was used to evaluate pleasure and arousal, and a bipolar scale was used to evaluate familiarity. The results showed a high correlation between familiarity and pleasure, but low correlation between familiarity and arousal. The characteristics of the stimuli, and their effect on the variables of pleasure, arousal and familiarity, were explored through ANOVA. It is suggested that, in the case of natural-scene ads, familiarity with image-headline combinations may increase the pleasure response to the ads, and that certain components in the images (e.g., water) may increase arousal levels.

  20. The fractal nature materials microstructure influence on electrochemical energy sources

    Directory of Open Access Journals (Sweden)

    Mitić V.V.

    2015-01-01

    Full Text Available With increasing of the world energy crisis, research for new, renewable and alternative energy sources are in growth. The focus is on research areas, sometimes of minor importance and applications, where the different synthesis methods and microstructure properties optimization, performed significant improvement of output materials’ and components’ electro-physical properties, which is important for higher energy efficiency and in the electricity production (batteries and battery systems, fuel cells and hydrogen energy contribution. Also, the storage tanks capacity improvement, for the energy produced on such way, which is one of the most important development issues in the energy sphere, represents a very promising research and application area. Having in mind, the results achieved in the electrochemical energy sources field, especially electrolyte development, these energy sources, materials fractal nature optimization analysis contribution, have been investigated. Based on materials fractal structure research field, particularly electronic materials, we have performed microstructure influence parameters research in electrochemistry area. We have investigated the Ho2O3 concentration influence (from 0.01wt% to 1wt% and sintering temperature (from 1320°C to 1380°C, as consolidation parameters, and thus, also open the electrochemical function fractalization door and in the basic thermodynamic parameters the fractal correction introduced. The fractal dimension dependence on additive concentration is also investigated. [Projekat Ministarstva nauke Republike Srbije, br. 172057: Directed synthesis, structure and properties of multifunctional materials

  1. Influence of diabetes on the pharmacokinetic behavior of natural polyphenols.

    Science.gov (United States)

    Xiao, Jianbo; Högger, Petra

    2014-01-01

    The development of food fortified with polyphenols and polyphenol-rich foods represents a novel approach to prevent or attenuate type 2 diabetes. It has been reported that type 2 diabetes may affect the pharmacokinetics of various drugs in several animal models. There is powerful evidence linking dietary polyphenols consumption with the risk factors defining type 2 diabetes, even if some opposite results occurred. This mini-review summarizes important advances on diabetes-associated changes in pharmacokinetics of natural polyphenols. The pharmacokinetic behavior between drugs and dietary polyphenols probably may be different due to (i) Ingested dose/amount per day. The dietary polyphenol intake per day is much higher than that of clinical drugs; (ii) Complexity of the components. Clinical drugs are well-characterized and typically small molecules. However, the polyphenols in diet are unimaginably complex; (iii) Interaction with food proteins. Although the effects of food proteins on the bioavailability of polyphenols are still not examined in much detail, direct binding interactions of polyphenols to proteins always occur; (iv) The most common polyphenols in the human diet have a low intrinsic activity and are poorly absorbed from the intestine, highly metabolized, or rapidly eliminated. Although there is very limited information available so far, it is proposed that type 2 diabetes influences the pharmacokinetic behavior of dietary polyphenols including: i) competition of glucose with polyphenols regarding binding to plasma proteins; ii) weakened non-covalent interaction affinities of plasma proteins for natural polyphenols due to protein glycation in type II diabetes; iii) the enhanced clearance of polyphenols in type 2 diabetes. An understanding of diabetes-associated changes in absorption, distribution, metabolism, elimination and bioactivities of natural polyphenols as well as the mechanism of the variability should lead to the improvement of the benefits of

  2. INFLUENCE OF NATURAL ADDITIVES ON PROTEIN COMPLEX OF BREAD

    Directory of Open Access Journals (Sweden)

    Dana Urminská

    2010-11-01

    Full Text Available The study focuses on researching the influence of natural additives on certain technological characteristics of mixtures used for bread production, more particularly the influence of N substances in used raw material on selected qualitative parameters of bread. The blends for bread production to be analysed were prepared by mixing wheat flour with an addition of oat, buckwheat, lentil and chickpea wholegrain flour in different portions (10, 20, 30, 40 and 50 %. The experiment showed that the addition of natural additives worsened the protein complex of the blends used in bread production (worsening also qualitative parameters known as product volume. The loaves prepared with an addition of buckwheat, oat, lentil and chickpea were evaluated to be of a lesser quality from a technological viewpoint when compared with pure wheat loaves. The lower content of gluten forming proteins and the generally changed protein composition of blends due to additives caused a lower percentage of wet gluten content, its lower extensibility and swelling capacity. The sedimentation value (Zeleny index decreased proportionally with the increase of addition until the level was unsatisfactory for raw material intended for bakery purposes. The N content in experimental loaves was higher than in the reference loaves and it increased according to the selected additive and its portion in the blend (more with the addition of lentil and chickpea, less in case of buckwheat and oat which is considered as positive from a nutritional point of view. But from the technological point of view the additives did not show any positive influence and caused a lower loaf bread volume. The most significant decrease of the loaf bread volume was found with the addition of 50 % of buckwheat (- 45.6 %. Better results were obtained with a lower portion of the additive: loaf with an addition of 30 % of chickpea (volume decreased by 12.8 % > loaf with an addition of 30 % of lentil (volume

  3. Effect of natural phosphate to remove silver interference in the detection of mercury(II) in aquatic algae and seawater samples

    OpenAIRE

    S. Lahrich; H. Hammani; W. Boumya; A. Loudiki; El Bouabi; R. Elmoubarki; A. Farahi; M. Achak; M. Bakasse; M.A. El Mhammedi

    2016-01-01

    A silver particles impregnated onto natural phosphate (Ag/NP) was synthesized using reaction in solid state. The obtained powder was characterized by X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). The (Ag/NP) was used as modifier of carbon paste electrode (CPE) to determine mercury by square wave voltammetry. The calibration graph obtained is linear from 1.0 × 10−8 mol·L−1 to 1.0 × 10−5 mol·L−1 at preconcentration time of 5 min, percentage loading of 7%, with correla...

  4. Effect of different seawater Mg

    NARCIS (Netherlands)

    Mewes, A.; Langer, G.; de Nooijer, L.J.; Bijma, J.; Reichart, G.J.

    2014-01-01

    Magnesium, incorporated in foraminiferal calcite (Mg/CaCC), is used intensively to reconstruct past seawater temperatures but, in addition to temperature, the Mg/CaCC of foraminiferal tests also depends on the ratio of Mg and Ca in seawater (Mg/CaSW). The physiological mechanisms responsible for

  5. Perceived naturalness and evoked disgust influence acceptance of cultured meat.

    Science.gov (United States)

    Siegrist, Michael; Sütterlin, Bernadette; Hartmann, Christina

    2018-05-01

    Cultured meat could be a more environment- and animal-friendly alternative to conventional meat. However, in addition to the technological challenges, the lack of consumer acceptance could be a major barrier to the introduction of cultured meat. Therefore, it seems wise to take into account consumer concerns at an early stage of product development. In this regard, we conducted two experiments that examined the impact of perceived naturalness and disgust on consumer acceptance of cultured meat. The results of Experiment 1 suggest the participants' low level of acceptance of cultured meat because it is perceived as unnatural. Moreover, informing participants about the production of cultured meat and its benefits has the paradoxical effect of increasing the acceptance of traditional meat. Experiment 2 shows that how cultured meat is described influences the participants' perception. Thus, it is important to explain cultured meat in a nontechnical way that emphasizes the final product, not the production method, to increase acceptance of this novel food. Copyright © 2018 Elsevier Ltd. All rights reserved.

  6. Fuel Production from Seawater and Fuel Cells Using Seawater.

    Science.gov (United States)

    Fukuzumi, Shunichi; Lee, Yong-Min; Nam, Wonwoo

    2017-11-23

    Seawater is the most abundant resource on our planet and fuel production from seawater has the notable advantage that it would not compete with growing demands for pure water. This Review focuses on the production of fuels from seawater and their direct use in fuel cells. Electrolysis of seawater under appropriate conditions affords hydrogen and dioxygen with 100 % faradaic efficiency without oxidation of chloride. Photoelectrocatalytic production of hydrogen from seawater provides a promising way to produce hydrogen with low cost and high efficiency. Microbial solar cells (MSCs) that use biofilms produced in seawater can generate electricity from sunlight without additional fuel because the products of photosynthesis can be utilized as electrode reactants, whereas the electrode products can be utilized as photosynthetic reactants. Another important source for hydrogen is hydrogen sulfide, which is abundantly found in Black Sea deep water. Hydrogen produced by electrolysis of Black Sea deep water can also be used in hydrogen fuel cells. Production of a fuel and its direct use in a fuel cell has been made possible for the first time by a combination of photocatalytic production of hydrogen peroxide from seawater and dioxygen in the air and its direct use in one-compartment hydrogen peroxide fuel cells to obtain electric power. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Uranium extraction from seawater

    International Nuclear Information System (INIS)

    Bals, H.G.

    1976-03-01

    After an introduction to the physics and chemistry of the sea and an estimation of the chances for the absorption of uranium from rivers, the material-sepecific characteristics of the adsorber technology are decribed in detail. Then, the methods used for gaining uranium form seawater are described with special regard to the tidal and the so-called serial (sequency) method. Whether all methods described can be realised is an economic problem since very high quantitics of water are necessary because of the low contents of uranium. A positive energy balance (gained energy/lost energy) is not definitely ensured yet for the production methods used. The development measures to be taken to obtain a positive energy balance are briefly described, and the research programme of the UEBG is mentioned. (UA) [de

  8. Evaluation of durability of SSCs injected with seawater

    International Nuclear Information System (INIS)

    2012-01-01

    At the units 1 to 4 in the Fukushima Daiichi Nuclear Power Plant, seawater was injected into reactor pressure vessels and spent fuel pools in order to cool down nuclear fuel is after the disaster of the 2011 off the Pacific Coast of Tohoku Earthquake and Tsunami. Therefore, for fuel cladding tubes exposed to seawater and piping items to pour seawater into a nuclear reactor, it was necessary to evaluate structural integrity under the seawater environment. And then, JNES carried out the safety research of 'Evaluation of Durability of SSCs injected with Seawater' in FY2011. The contents and the results obtained from the search are as follows; (1) For the pipes and nuclear reactor containment vessels, corrosion tests under high temperature seawater at 50degC and 80degC were carried out for the carbon steel that corrosion resistance was less. The data of relationship between a dipping time upto 1,500h and a corrosion rate were obtained as parameters at chloride ion (CI - ) content and the temperature of the seawater. As the results, the corrosion rate was almost 0.1 mm/y for the carbon steel SGV480. No significant influence of CT - content and the temperature of the seawater was confirmed. (2) Corrosion tests were carried out to obtain the relations of time and corrosion under different CI - content conditions for the simulated fuel rod specimens in seawater at 90degC for durations upto 1,200h. As the results, very little corrosion was observed on Zry-2 cladding tube. Brown rust was slightly appeared on the nut made of stainless steel and the lower tie plate made of cast stainless steel. Thinning and corrosion pit were not observed. (author)

  9. Impediment to Symbiosis Establishment between Giant Clams and Symbiodinium Algae Due to Sterilization of Seawater

    Science.gov (United States)

    Kurihara, Takeo; Yamada, Hideaki; Inoue, Ken; Iwai, Kenji; Hatta, Masayuki

    2013-01-01

    To survive the juvenile stage, giant clam juveniles need to establish a symbiotic relationship with the microalgae Symbiodinium occurring in the environment. The percentage of giant clam juveniles succeeding in symbiosis establishment (“symbiosis rate”) is often low, which is problematic for seed producers. We investigated how and why symbiosis rates vary, depending on whether giant clam seeds are continuously reared in UV treated or non treated seawater. Results repeatedly demonstrated that symbiosis rates were lower for UV treated seawater than for non treated seawater. Symbiosis rates were also lower for autoclaved seawater and 0.2-µm filtered seawater than for non treated seawater. The decreased symbiosis rates in various sterilized seawater suggest the possibility that some factors helping symbiosis establishment in natural seawater are weakened owing to sterilization. The possible factors include vitality of giant clam seeds, since additional experiments revealed that survival rates of seeds reared alone without Symbiodinium were lower in sterilized seawater than in non treated seawater. In conclusion, UV treatment of seawater was found to lead to decreased symbiosis rates, which is due possibly to some adverse effects common to the various sterilization techniques and relates to the vitality of the giant clam seeds. PMID:23613802

  10. Impediment to symbiosis establishment between giant clams and Symbiodinium algae due to sterilization of seawater.

    Science.gov (United States)

    Kurihara, Takeo; Yamada, Hideaki; Inoue, Ken; Iwai, Kenji; Hatta, Masayuki

    2013-01-01

    To survive the juvenile stage, giant clam juveniles need to establish a symbiotic relationship with the microalgae Symbiodinium occurring in the environment. The percentage of giant clam juveniles succeeding in symbiosis establishment ("symbiosis rate") is often low, which is problematic for seed producers. We investigated how and why symbiosis rates vary, depending on whether giant clam seeds are continuously reared in UV treated or non treated seawater. Results repeatedly demonstrated that symbiosis rates were lower for UV treated seawater than for non treated seawater. Symbiosis rates were also lower for autoclaved seawater and 0.2-µm filtered seawater than for non treated seawater. The decreased symbiosis rates in various sterilized seawater suggest the possibility that some factors helping symbiosis establishment in natural seawater are weakened owing to sterilization. The possible factors include vitality of giant clam seeds, since additional experiments revealed that survival rates of seeds reared alone without Symbiodinium were lower in sterilized seawater than in non treated seawater. In conclusion, UV treatment of seawater was found to lead to decreased symbiosis rates, which is due possibly to some adverse effects common to the various sterilization techniques and relates to the vitality of the giant clam seeds.

  11. Influence of different natural physical fields on biological processes

    Science.gov (United States)

    Mashinsky, A. L.

    2001-01-01

    In space flight conditions gravity, magnetic, and electrical fields as well as ionizing radiation change both in size, and in direction. This causes disruptions in the conduct of some physical processes, chemical reactions, and metabolism in living organisms. In these conditions organisms of different phylogenetic level change their metabolic reactions undergo changes such as disturbances in ionic exchange both in lower and in higher plants, changes in cell morphology for example, gyrosity in Proteus ( Proteus vulgaris), spatial disorientation in coleoptiles of Wheat ( Triticum aestivum) and Pea ( Pisum sativum) seedlings, mutational changes in Crepis ( Crepis capillaris) and Arabidopsis ( Arabidopsis thaliana) seedling. It has been found that even in the absence of gravity, gravireceptors determining spatial orientation in higher plants under terrestrial conditions are formed in the course of ontogenesis. Under weightlessness this system does not function and spatial orientation is determined by the light flux gradient or by the action of some other factors. Peculiarities of the formation of the gravireceptor apparatus in higher plants, amphibians, fish, and birds under space flight conditions have been observed. It has been found that the system in which responses were accompanied by phase transition have proven to be gravity-sensitive under microgravity conditions. Such reactions include also the process of photosynthesis which is the main energy production process in plants. In view of the established effects of microgravity and different natural physical fields on biological processes, it has been shown that these processes change due to the absence of initially rigid determination. The established biological effect of physical fields influence on biological processes in organisms is the starting point for elucidating the role of gravity and evolutionary development of various organisms on Earth.

  12. Sexual and Natural Selection Both Influence Male Genital Evolution

    OpenAIRE

    House, Clarissa M.; Lewis, Zenobia; Hodgson, Dave J.; Wedell, Nina; Sharma, Manmohan D.; Hunt, John; Hosken, David J.

    2013-01-01

    Rapid and divergent evolution of male genital morphology is a conspicuous and general pattern across internally fertilizing animals. Rapid genital evolution is thought to be the result of sexual selection, and the role of natural selection in genital evolution remains controversial. However, natural and sexual selection are believed to act antagonistically on male genital form. We conducted an experimental evolution study to investigate the combined effects of natural and sexual selection on ...

  13. Uranium recovery from seawater

    International Nuclear Information System (INIS)

    Bitte, J.; Fremery, M.I.; Kellner, A.; Schroeer, K.; Knippenberg, W.

    1984-09-01

    The present publication describes the development work of a process to recover uranium from seawater and the proposition of a commercial demonstration plant. The essential components of this process are verified in the laboratory scale as well as in some field tests. A detailed engineering design for a model plant in a semi-technical scale to allow field tests in the marine environment is also presented. These field tests are expected to produce more realistic data on the technical and economical feasibility of the proposed technology. Production cost estimates based on state-of-the-art technology lie around 250 Dollar/1b U 3 O 8 . However, the effect of a corresponding uranium price increase on electricity costs are comparable to cost increases in coal operated power plants caused by the desulfurisation of coal. Further reductions of the production costs in the range below 150 Dollar/1b U 3 O 8 seem possible through special research efforts in the area of sorber development and concept design. (orig.) [de

  14. Net Community Metabolism and Seawater Carbonate Chemistry Scale Non-intuitively with Coral Cover

    Directory of Open Access Journals (Sweden)

    Heather N. Page

    2017-05-01

    highlight the need to consider the natural complexity of reefs and additional biological and physical factors that influence seawater carbonate chemistry on larger spatial and longer temporal scales. Coordinated efforts combining various research approaches (e.g., experiments, field studies, and models will be required to better understand how benthic metabolism integrates across functional, spatial, and temporal scales, and for making predictions on how coral reefs will respond to climate change.

  15. Rapid and gradual modes of aerosol trace metal dissolution in seawater

    Directory of Open Access Journals (Sweden)

    Katherine Rose Marie Mackey

    2015-01-01

    Full Text Available Atmospheric deposition is a major source of trace metals in marine surface waters and supplies vital micronutrients to phytoplankton, yet measured aerosol trace metal solubility values are operationally defined and there are relatively few multi-element studies on aerosol-metal solubility in seawater. Here we measure the solubility of aluminum (Al, cadmium (Cd, cobalt (Co, copper (Cu, iron (Fe, manganese (Mn, nickel (Ni, lead (Pb, and zinc (Zn from natural aerosol samples in seawater over a 7 day period to (1 evaluate the role of extraction time in trace metal dissolution behavior and (2 explore how the individual dissolution patterns could influence biota. Dissolution behavior occurs over a continuum ranging from rapid dissolution, in which the majority of soluble metal dissolved immediately upon seawater exposure (Cd and Co in our samples, to gradual dissolution, where metals dissolved slowly over time (Zn, Mn, Cu, and Al in our samples. Additionally, dissolution affected by interactions with particles was observed in which a decline in soluble metal concentration over time occurred (Fe and Pb in our samples. Natural variability in aerosol chemistry between samples can cause metals to display different dissolution kinetics in different samples, and this was particularly evident for Ni, for which samples showed a broad range of dissolution rates. The elemental molar ratio of metals in the bulk aerosols was 23,189Fe: 22,651Al: 445Mn: 348Zn: 71Cu: 48Ni: 23Pb: 9Co: 1Cd, whereas the seawater soluble molar ratio after 7 days of leaching was 11Fe: 620Al: 205Mn: 240Zn: 20Cu: 14Ni: 9Pb: 2Co: 1Cd. The different kinetics and ratios of aerosol metal dissolution have implications for phytoplankton nutrition, and highlight the need for unified extraction protocols that simulate aerosol metal dissolution in the surface ocean.

  16. Neodymium isotopic variations in seawater

    International Nuclear Information System (INIS)

    Piepgras, D.J.; Wasserburg, G.J.

    1980-01-01

    New data for the direct measurement of the isotopic composition of neodymium in Atlantic Ocean seawater are compared with previous measurements of Pacific Ocean seawater and ferromanganese sediments from major ocean basins. Data for Atlantic seawater are in excellent agreement with Nd isotopic measurements made on Atlantic ferromanganese sediments and are distinctly different from the observed compositions of Pacific samples. These results clearly demonstrate the existence of distinctive differences in the isotopic composition of Nd in the waters of the major ocean basins and are characteristic of the ocean basin sampled. The average epsilonsub(N)sub(d)(0) values for the major oceans as determined by data from seawater and ferromanganese sediments are as follows: Atlantic Ocean, epsilonsub(N)sub(d)(0) approx. equal to - 12 +- 2; Indian Ocean, epsilonsub(N)sub(d)(0) approx. equal to - 8 +- 2; Pacific Ocean, epsilonsub(N)sub(d)(0) approx. equal to -3 +- 2. These values are considerably less than epsilonsub(N)sub(d)(0) value sources with oceanic mantle affinities indicating that the REE in the oceans are dominated by continental sources. The difference in the absolute abundance of 143 Nd between the Pacific and Atlantic Oceans corresponds to approx. 10 6 atoms 143 Nd per gram of seawater. The correspondence between the 143 Nd/ 144 Nd in seawater and in the associated sediments suggests the possible application of this approach to paleo-oceanography. (orig./HAE)

  17. Improvement of seawater booster pump outlet check valve

    International Nuclear Information System (INIS)

    Li Xuning; Du Yansong; Huang Huimin

    2010-01-01

    Conventional island seawater booster pump set of QNPC 310 MWe unit are very important in the whole circulating cooling system, and the integrate function of seawater booster pump outlet check valve is the foundation of steady operation of the seawater booster pump set. The article mainly introduce that through the analyses to the reason to the problem that the seawater booster pump outlet check valve of QNPC 310 MWe unit appeared in past years by our team, and considering the influence of operation condition and circumstance, the team improve the seawater booster pump outlet check valve from swing check valve to shuttle check valve which operate more appropriately in the system. By the test of continuous practice, we make further modification to the inner structure of shuttle check valve contrapuntally, and therefore we solve the problem in seawater booster pump outlet check valve fundamentally which has troubled the security of system operation in past years, so we realize the aim of technical improvement and ensure that the system operate in safety and stability. (authors)

  18. Calcium extraction from brine water and seawater using oxalic acid

    Science.gov (United States)

    Natasha, Nadia Chrisayu; Lalasari, Latifa Hanum

    2017-01-01

    Calcium can be extracted not only from rocks but also from natural liquor such as seawater and brine water. In order to extract the calcium from seawater and brine water, oxalic acid was used in this research. Effect of variations of the volume of the oxalic acid at a constant concentration in seawater and brine water to produce calcium was investigated. The concentration of oxalic acid was 100 g/l and the variations of its volume were 2 ml, 4 ml, 6 ml, 8 ml, 10 ml, 20 ml, 30 ml, 40 ml, and 50 ml. The used seawater and brine water were firstly evaporated from 100 ml into 50 ml and then the oxalic acid was added into them with mixing to produce the calcium precipitates. The precipitates were analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM) and the filtrates were analyzed by inductively coupled plasma-optical emission spectrometry (ICP-OES). The SEM analysis showed that the precipitates from brine water were consisted of only calcium compound while from seawater sodium one was also found along with calcium compound. The XRD analysis showed that the calcium was present in the form of calcium oxalate for both seawater and brine water. The ICP-OES analysis of the filtrate from seawater precipitation showed that the its calcium content was decreased from 826.20 ppm to 0.04 ppm while from brine water, it decreased from 170.06 ppm to 1.96 ppm. These results showed that both seawater and brine water have the potential to be a raw material for calcium production.

  19. Influence of Stockpile Angle in Natural Drying of Laterite Ore

    Directory of Open Access Journals (Sweden)

    Yoalbys Retirado-Mediaceja

    2016-10-01

    Full Text Available Natural drying is performed at Cuban nickel plants by depositing bulk ore in the open. The ore is currently being stockpiled without much consideration for the impact of the drying surface angle on the process power behavior. Simulations were carried out in this investigation, which prove that an increased triangular stockpile angle considerably reduces natural drying efficiency. A 45 sexagesimal degree angle to the horizontal plane results in exposure of a large volume of ore to natural drying and guarantees adequate energy performance.

  20. Rate of mass deposition of scaling compounds from seawater on the outer surface of heat exchangers in MED evaporators

    Energy Technology Data Exchange (ETDEWEB)

    Omar, W. [Department of Natural Resources and Chemical Engineering, Tafila Technical University, Tafila (Jordan); Ulrich, J. [FB Ingenieurwissenschaften, Institut fuer Verfahrenstechnik/TVT, Martin-Luther-Universitaet Halle-Wittenberg, Halle (Germany)

    2006-08-15

    The scaling problem in Multi Effect Distillation (MED) evaporators is investigated by the experimental measurement of the deposition rate under different operating conditions. The measurements are conducted in a batch vessel containing artificial seawater, which is allowed to contact the outer surface of a hot pipe under controlled temperature, salinity and pH. The rate of mass deposition is higher at elevated temperature. The salinity of the seawater also influences the scaling process - an increase in salinity from 47-59 g/L leads to an increase of 75.6 % in the deposition rate. Decreasing the pH value of seawater to 2.01 results in a complete inhibition of scaling, whereas the severity of the scaling increases in neutral and basic mediums. Polyacrylic acid is tested as an antifoulant and it was found that its presence in seawater reduces the scaling process. The nature of the heat transfer surface material also plays an important role in the scaling process. It is found experimentally that the rate of scaling is higher in the case of a Cu-Ni alloy as the surface material of the tube rather than stainless steel. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  1. Factors affecting seawater-based pretreatment of lignocellulosic date palm residues

    DEFF Research Database (Denmark)

    Fang, Chuanji; Thomsen, Mette Hedegaard; Frankaer, Christian Grundahl

    2017-01-01

    Seawater-based pretreatment of lignocellulosic biomass is an innovative process at research stage. With respect to process optimization, factors affecting seawater-based pretreatment of lignocellulosic date palm residues were studied for the first time in this paper. Pretreatment temperature (180...... °C–210 °C), salinity of seawater (0 ppt–50 ppt), and catalysts (H2SO4, Na2CO3, and NaOH) were investigated. The results showed that pretreatment temperature exerted the largest influence on seawater-based pretreatment in terms of the enzymatic digestibility and fermentability of pretreated solids...

  2. One-dimensional self-sealing ability of bentonites in artificial seawater

    International Nuclear Information System (INIS)

    Komine, Hideo; Yasuhara, Kazuya; Murakami, Satoshi

    2009-01-01

    A high-level radioactive waste disposal facility might be built in a coastal area in Japan from the viewpoint of feasible transportation of waste. Therefore, it is important to investigate the effects of seawater on a bentonite-based buffer. This study investigated the influence of seawater on self-sealing ability of three common sodium-types of bentonite by the laboratory experiment and chemical analysis. From the results of laboratory experiment, suitable specifications were defined for a bentonite-based buffer that can withstand the effects of seawater. Furthermore, mechanism on filtration of seawater components in highly compacted bentonite was discussed by the results of chemical analysis. (author)

  3. Incidence of Vibrio cholerae and related vibrios in a coastal lagoon and seawater influenced by lake discharges along an annual cycle.

    Science.gov (United States)

    Garay, E; Arnau, A; Amaro, C

    1985-08-01

    Most probable numbers of Vibrio cholerae and related vibrios were determined in Albufera Lake, Valencia, Spain, and in coastal waters under the influence of the lake discharges over the course of an annual cycle. The influence of temperature, kind of water, and characteristics of the different sampling sites on the numbers of vibrios recovered was evaluated. Maximum recovery of vibrios reached 10(3)/ml in both types of waters analyzed. V. cholerae numbers reached 10(3)/ml in the lake and 10(2) in one of the coastal sites. Frequently during the warm season, all vibrios isolated were identified as V. cholerae. Occasionally, no V. cholerae was recovered. The recovery of vibrios was significantly influenced by the temperature of the water and the type of water analyzed. Most of the V. cholerae isolates were included in Heiberg groups I and II, and nearly 50% of the strains used chitin as sole carbon source. Indole was not produced by 100% of the strains. All strains tested were non-O1 serovars.

  4. Role of bacteria in marine barite precipitation : A case study using Mediterranean seawater

    NARCIS (Netherlands)

    Torres-Crespo, N.; Martínez-Ruiz, F.; González-Muñoz, M. T.; Bedmar, E. J.; De Lange, G. J.; Jroundi, F.

    2015-01-01

    Marine bacteria isolated from natural seawater were used to test their capacity to promote barite precipitation under laboratory conditions. Seawater samples were collected in the western and eastern Mediterranean at 250. m and 200. m depths, respectively, since marine barite formation is thought to

  5. XAS and TRLIF spectroscopy of uranium and neptunium in seawater.

    Science.gov (United States)

    Maloubier, Melody; Solari, Pier Lorenzo; Moisy, Philippe; Monfort, Marguerite; Den Auwer, Christophe; Moulin, Christophe

    2015-03-28

    Seawater contains radionuclides at environmental levels; some are naturally present and others come from anthropogenic nuclear activity. In this report, the molecular speciation in seawater of uranium(VI) and neptunium(V) at a concentration of 5 × 10(-5) M has been investigated for the first time using a combination of two spectroscopic techniques: Time-resolved laser-induced fluorescence (TRLIF) for U and extended X-ray absorption fine structure (EXAFS) for U and Np at the LIII edge. In parallel, the theoretical speciation of uranium and neptunium in seawater at the same concentration is also discussed and compared to spectroscopic data. The uranium complex was identified as the neutral carbonato calcic complex UO2(CO3)3Ca2, which has been previously described in other natural systems. In the case of neptunium, the complex identified is mainly a carbonato complex whose exact stoichiometry is more difficult to assess. The knowledge of the actinide molecular speciation and reactivity in seawater is of fundamental interest in the particular case of uranium recovery and more generally regarding the actinide life cycle within the biosphere in the case of accidental release. This is the first report of actinide direct speciation in seawater medium that can complement inventory data.

  6. Sr isotope stratigraphy of some Rupelian carbonated laminites from the Limagne Basin: influence of seawater in the rift of the French Massif central?

    International Nuclear Information System (INIS)

    Briot, D.; Poidevin, J.L.

    1998-01-01

    87 Sr/ 86 Sr ratios of biogenic and abiotic calcites Upper Rupelian sediments in the Limagne rift (French Massif Central) define a smooth and regular negative correlation with time interrupted by repetitive sharp peaks; the progressive drop in isotopic ratio can be explained by the geological evolution of the river basin through time. Negative peaks are explained by synsedimentary volcanism, repeated marine incursions, or leaching of ancient evaporites. Comparison with available paleontologic data does not favour the volcanic explanation, but rather the influence of Rupelian marine waters. (authors)

  7. Recovery of uranium from seawater

    International Nuclear Information System (INIS)

    Hirotsu, Takahiro; Takagi, Norio; Katoh, Shunsaku

    1995-01-01

    Present status of the development of chelating adsorbents for the recovery of uranium from seawater is outlined with emphasis on the research by the author. Uranium is estimated to exist as stable tri (carbonate) uranylate (6) ion in seawater in a very low concentration. The adsorbent for uranium from seawater in a very low concentration. The adsorbent for uranium from seawater should have high selectivity and affinity for uranium around pH 8. The required characteristics for uranium adsorbent are examined. Various chelating adsorbents have been proposed for the uranium adsorbent and their structures are discussed. Amidoxime type adsorbents have the highest adsorbing power for uranium among the adsorbents hitherto developed and fibrous amidoxime adsorbents are most promising for the practical application. Synthesis, structure and suitable shape of the amidoxime adsorbents are discussed. Uranium adsorption behavior and the amount of saturated adsorption are examined theoretically based on the complexation of an amidoxime monomer and the formula for the adsorption equiliburium is derived. The adsorption and recovery process for uranium from seawater is composed of adsorption, desorption, separation and concentration and finally, uranium is recovered as the yellow cake. A floating body mooring system is proposed by Nobukawa. (T.H.)

  8. The Influence of Argumentation on Understanding Nature of Science

    Science.gov (United States)

    Boran, Gül Hanim; Bag, Hüseyin

    2016-01-01

    The aim in conducting this study is to explore the effects of argumentation on pre-service science teachers' views of the nature of science. This study used a qualitative case study and conducted with 20 pre-service science teachers. Data sources include an open-ended questionnaire and audio-taped interviews. According to pretest and posttest…

  9. On the Influence of Naturalism on American Literature

    Science.gov (United States)

    Zhang, Xiaofen

    2010-01-01

    Naturalism was first proposed and formulated by French novelist Emile Zola, and it was introduced to America by American novelist Frank Norris. It is a new and harsher realism. It is a theory in literature emphasizing scientific observation of life without idealism or avoidance of the ugly. American literature naturalists dismissed the validity of…

  10. The influence of Algae on the natural environment

    NARCIS (Netherlands)

    Baas Becking, L.G.M.

    1958-01-01

    In the development of the various scientific disciplines certain contacts have been established between neighbouring sciences, while other endeavour still proceeds almost on its own. The study of the influence of the environment on chemical reactions has given us a large part of physical chemistry,

  11. Seawater desalination with nuclear power

    International Nuclear Information System (INIS)

    2005-01-01

    Nuclear power helps reduce costs for energy-intensive processes such as seawater desalination. A new generation of innovative small and medium nuclear power plants could co-generate electricity and potable water from seawater, both safely and at competitive prices in today's market. The IAEA provides technical support to Member States facing water shortage problems, on assessing the viability of nuclear power in seawater desalination. The support, usually channelled through national Technical Cooperation (TC) projects, can take several forms, ranging from educational training and technical advice on feasibility studies to design and safety review of demonstration projects. The IAEA offers a software tool (DEEP) that can be used to evaluate the economics of the different desalination and heat source configurations, including nuclear and fossil options

  12. Do natural science experiments influence public attitudes towards environmental problems?

    International Nuclear Information System (INIS)

    Wallner, A.; Hunziker, M.; Kienast, F.

    2003-01-01

    We investigated the significance of risk assessment studies in the public discussion on CO 2 emissions. Politicians and representatives from the public were interviewed by using the social-science technique of qualitative in-depth interviews. Three different types of attitudes towards natural science were found among politicians. Depending on which attitude a politician holds, risk assessment studies can have an impact on his/her readiness to support environmental policy measures. Regarding lay people, key factors affecting the acceptance of environmental policy measures are knowledge of environmental problems, their impacts on ecosystems or human health as well as direct personal perception of those impacts. Since direct perception is not always possible in everyday life, natural science experiments might be a means for successfully mediating this lacking perception. (author)

  13. Kinetics of Inorganic Calcite Dissolution in Seawater under Pressure

    Science.gov (United States)

    Dong, S.; Subhas, A.; Rollins, N.; Berelson, W.; Adkins, J. F.

    2016-02-01

    While understanding calcium carbonate dissolution is vital in constructing global carbon cycles and predicting the effect of seawater acidification as a result of increasing atmospheric CO2, there is still a major debate over the basic formulation of a dissolution rate law. The kinetics of calcium carbonate dissolution are typically described by the equation: Rate=k(1-Ω)n, while Ω=[Ca2+][CO32-]/Ksp. In this study, 13C-labeled calcite is dissolved in unlabeled seawater and the evolving d13C composition of the fluid is traced over time to establish dissolution rate. Instead of changing ion concentration to obtain varying Ω (as in our previous study; Subhas et al. 2015), we changed Ksp by conducting experiments under different pressures (described in theory as ∂lnKsp/∂P=-ΔV/RT, where ΔV is partial molal volume). This involved the construction of a pressure vessel that could hold our sample bag and provide aliquots while remaining pressurized. Pressure experiments were conducted between 0-2000PSI. Results support the conclusion in our previous study that near-equilibrium dissolution rates are highly nonlinear, but give a disparate relationship between undersaturation and dissolution rate if Ω is calculated assuming the specific ΔV embedded in CO2SYS. A revised ΔV from -37cm3 to -65cm3 would make the dissolution formulation equation agree, but clearly appears unreasonable. Our results are explained by a pressure effect on carbonate dissolution kinetics over and above the influence of pressure on Ω. If this is a phenomenon that occurs in nature, then we would predict that dissolution should be occurring shallower in the water column (as sometimes observed) than indicated by standard Ω calculations.

  14. Paleogene Seawater Osmium Isotope Records

    Science.gov (United States)

    Rolewicz, Z.; Thomas, D. J.; Marcantonio, F.

    2012-12-01

    Paleoceanographic reconstructions of the Late Cretaceous and early Cenozoic require enhanced geographic coverage, particularly in the Pacific, in order to better constrain meridional variations in environmental conditions. The challenge with the existing inventory of Pacific deep-sea cores is that they consist almost exclusively of pelagic clay with little existing age control. Pelagic clay sequences are useful for reconstructions of dust accumulation and water mass composition, but accurate correlation of these records to other sites requires improved age control. Recent work indicates that seawater Os isotope analyses provide useful age control for red clay sequences. The residence time of Os in seawater is relatively long compared to oceanic mixing, therefore the global seawater 187Os/188Os composition is practically homogeneous. A growing body of Late Cretaceous and Cenozoic data has constrained the evolution of the seawater Os isotopic composition and this curve is now a viable stratigraphic tool, employed in dating layers of Fe-Mn crusts (e.g., Klemm et al., 2005). Ravizza (2007) also demonstrated that the seawater Os isotopic composition can be extracted reliably from pelagic red clay sediments by analyzing the leached oxide minerals. The drawback to using seawater Os isotope stratigraphy to date Paleogene age sediments is that the compilation of existing data has some significant temporal gaps, notably between ~38 and 55 Ma. To improve the temporal resolution of the seawater Os isotope curve, we present new data from Ocean Drilling Program (ODP) Site 865 in the equatorial Pacific. Site 865 has excellent biostratigraphic age control over the interval ~38-55Ma. Preliminary data indicate an increase in the seawater composition from 0.427 at 53.4 Ma to 0.499 by 43 Ma, consistent with the apparent trend in the few existing data points. We also analyzed the Os isotopic composition recorded by oxide minerals at Integrated Ocean Drilling Program (IODP) Site U1370

  15. Neodymium isotopic variations in seawater

    Science.gov (United States)

    Piepgras, D. J.; Wasserburg, G. J.

    1980-01-01

    Direct measurement of the isotopic composition of Nd in the Atlantic agree with the Nd content in ferromanganese sediments and differ from the observed amounts in the Pacific samples. These data indicate the existence of distinctive differences in the isotopic composition of Nd in the waters of major oceans; the average values determined from seawater and ferromanganese sediments are considerably lower than in sources with oceanic mantle affinities showing that the REE in the oceans is dominated by continental sources. The Nd isotopic variations in seawater are applied to relate the residence time of Nd and mixing rates between the oceans.

  16. Influence of electrolyte nature on steel membrane hydrogen permeability

    International Nuclear Information System (INIS)

    Lisovskij, A.P.; Nazarov, A.P.; Mikhajlovskij, Yu.N.

    1993-01-01

    Effect of electrolyte nature on hydrogen absorption of carbonic steel membrane at its cathode polarization is studied. Electrolyte buffering by anions of subdissociated acids is shown to increase hydrogen flow though the membrane in acid electrolytes. Mechanisms covering dissociation of proton-bearing anion in the electrolyte near-the-electron layer or dissociative adsorption on steel surface are suggested. Effect of proton-bearing bases forming stable complex compounds with iron, is studied. Activation of anode process of iron solution is shown to increase the rate of hydrogen penetration

  17. Influence of natural and recombinant interferons on development of antiviral condition and activity of natural killers

    International Nuclear Information System (INIS)

    Kuznetsov, V.P.; Avdeev, G.I.; Vyadro, M.M.; Leikin, Yu.D.; Frolova, I.S.

    1986-01-01

    For the purpose of a preliminary estimate of the therapeutic potential of domestic recombinant alpha 2 -component of human leukocytic interferon (rl) in vitro tests, the authors studied its ability to induce development of antiviral condition in diploid culture of human embryo fibroblasts and to activate the cytolytic effect of natural killers in relation to tumor cells, of the K-562 leukemia line and cells of lung adenocarcinoma. The authors used a medicinal form of rL which was derived by expression of a reconstructed gene in Escherichia coli cells. Part of the tests were conducted with an analogous preparation synthesized using another producer, Pseudomonas sp). The biological effect of both preparations was the same. For comparison, a natural preparation was used in all tests: human leukocytic interferon for injection, II(le). The authors studied activity of natural killers in a fraction of mononuclears isolated from blood of essentially healthy donors and from cancer patients. Cells were incubated for 2 h with various concentrations of interferons, then combined in a ratio of 25-50:1 with target cells labeled with 51 Cr. Cytotoxic reaction was conducted for 4 (4-CTR) or 18 h (18-CTR) at 37 0 C. Natural killers could thus be divided into two subpopulations: killer (4-CTR) and cytotoxic (18-CTR) cells. In preliminary tests, both preparations possessed the ability to active natural killers. The effective concentration for rL was within the limits of 1000-2000 IU/ml, and 50-200 Iu/ml for Le. The data on activation of natural killers in 16 oncological patients (primarily with lung cancer), the authors established that both rL and Le induced activation of natural killers in the overwhelming majority of cases in relation to K-562 target cells and adenocarcinomas of the lung

  18. Analytical approximations to seawater optical phase functions of scattering

    Science.gov (United States)

    Haltrin, Vladimir I.

    2004-11-01

    This paper proposes a number of analytical approximations to the classic and recently measured seawater light scattering phase functions. The three types of analytical phase functions are derived: individual representations for 15 Petzold, 41 Mankovsky, and 91 Gulf of Mexico phase functions; collective fits to Petzold phase functions; and analytical representations that take into account dependencies between inherent optical properties of seawater. The proposed phase functions may be used for problems of radiative transfer, remote sensing, visibility and image propagation in natural waters of various turbidity.

  19. Influence of land-use dynamics on natural hazard risk

    Science.gov (United States)

    Piazza, Giacomo; Thaler, Thomas; Fuchs, Sven

    2016-04-01

    In the recent past the magnitude and frequency of natural hazard events has increased notably worldwide, along with global GDP. A higher number of elements are exposed to natural events, therefore the risk is higher. Both estimated losses and understanding about natural hazards have increased during the past decades, which is contradictory as we may logically think. Risk is increasing, due to climate change and societal change: more severe hazards are happening due to changing climatic patterns and conditions, while society is concentrating assets and people in punctual places leading to a higher exposure. Increasing surface of settled area and the concentration of highly valuable assets (e.g. technology) in exposed areas lead to higher probability of losses. Human use of land resources, namely landuse, is the product of human needs and biophysical characteristics of the land. Landuse involves arrangements, activities and inputs people undertake in a certain land cover type to produce, change or maintain it. These changes are due to many reasons, or driving factors: socio-economical, environmental, accessibility to land, land-tenure, etc. The change of those factors may cause many effects and impacts, at various levels and at different time spans. The relation between driving factors and impacts is not straight. It is although a complex interrelation that turns around two central questions: (1) what drives landuse changes and why and (2) what are the impacts on the environment and on the human society of these changes, regarding to natural hazards. The aim of this paper is to analyse the spatio-temporal environmental changes referring to exposure as well as to test the possibilities and limitations of the land use change model Dyna-CLUEs in a mountain region taking parts of the Republic of Austria as an example, and simulating the future landuse dynamics until 2030. We selected an area composed by eighteen municipalities in the Ill-Walgau in the Austrian federal

  20. Seawater-cultured Botryococcus braunii for efficient hydrocarbon extraction.

    Directory of Open Access Journals (Sweden)

    Kenichi Furuhashi

    Full Text Available As a potential source of biofuel, the green colonial microalga Botryococcus braunii produces large amounts of hydrocarbons that are accumulated in the extracellular matrix. Generally, pretreatment such as drying or heating of wet algae is needed for sufficient recoveries of hydrocarbons from B. braunii using organic solvents. In this study, the Showa strain of B. braunii was cultured in media derived from the modified Chu13 medium by supplying artificial seawater, natural seawater, or NaCl. After a certain period of culture in the media with an osmotic pressure corresponding to 1/4-seawater, hydrocarbon recovery rates exceeding 90% were obtained by simply mixing intact wet algae with n-hexane without any pretreatments and the results using the present culture conditions indicate the potential for hydrocarbon milking.Seawater was used for efficient hydrocarbon extraction from Botryococcus braunii. The alga was cultured in media prepared with seawater or NaCl. Hydrocarbon recovery rate exceeding 90% was obtained without any pretreatment.

  1. Faraday's Law and Seawater Motion

    Science.gov (United States)

    De Luca, R.

    2010-01-01

    Using Faraday's law, one can illustrate how an electromotive force generator, directly utilizing seawater motion, works. The conceptual device proposed is rather simple in its components and can be built in any high school or college laboratory. The description of the way in which the device generates an electromotive force can be instructive not…

  2. Methane-oxidizing seawater microbial communities from an Arctic shelf

    Science.gov (United States)

    Uhlig, Christiane; Kirkpatrick, John B.; D'Hondt, Steven; Loose, Brice

    2018-06-01

    Marine microbial communities can consume dissolved methane before it can escape to the atmosphere and contribute to global warming. Seawater over the shallow Arctic shelf is characterized by excess methane compared to atmospheric equilibrium. This methane originates in sediment, permafrost, and hydrate. Particularly high concentrations are found beneath sea ice. We studied the structure and methane oxidation potential of the microbial communities from seawater collected close to Utqiagvik, Alaska, in April 2016. The in situ methane concentrations were 16.3 ± 7.2 nmol L-1, approximately 4.8 times oversaturated relative to atmospheric equilibrium. The group of methane-oxidizing bacteria (MOB) in the natural seawater and incubated seawater was > 97 % dominated by Methylococcales (γ-Proteobacteria). Incubations of seawater under a range of methane concentrations led to loss of diversity in the bacterial community. The abundance of MOB was low with maximal fractions of 2.5 % at 200 times elevated methane concentration, while sequence reads of non-MOB methylotrophs were 4 times more abundant than MOB in most incubations. The abundances of MOB as well as non-MOB methylotroph sequences correlated tightly with the rate constant (kox) for methane oxidation, indicating that non-MOB methylotrophs might be coupled to MOB and involved in community methane oxidation. In sea ice, where methane concentrations of 82 ± 35.8 nmol kg-1 were found, Methylobacterium (α-Proteobacteria) was the dominant MOB with a relative abundance of 80 %. Total MOB abundances were very low in sea ice, with maximal fractions found at the ice-snow interface (0.1 %), while non-MOB methylotrophs were present in abundances similar to natural seawater communities. The dissimilarities in MOB taxa, methane concentrations, and stable isotope ratios between the sea ice and water column point toward different methane dynamics in the two environments.

  3. Comparative influence of dose rate and radiation nature, on lethality after big mammals irradiation

    International Nuclear Information System (INIS)

    Destombe, C.; Le Fleche, Ph.; Grasseau, A.; Reynal, A.

    1997-01-01

    For the same dose and the 30 days lethality as biological criterion, the dose rate influence is more important than the radiation nature on the results of an big mammals total body irradiation. (authors)

  4. Naturally occurring and radiation-induced tumors in SPF mice, and genetic influence in radiation leukemogenesis

    International Nuclear Information System (INIS)

    Kasuga, T.

    1979-01-01

    The data obtained so far in this study point to a strong genetic influence not only on the types and incidence of naturally occurring and radiation-induced tumors but also on radiation leukemogenesis. (Auth.)

  5. Influence of natural and synthetic histone deacetylase inhibitors on chromatin.

    Science.gov (United States)

    Licciardi, Paul V; Kwa, Faith A A; Ververis, Katherine; Di Costanzo, Natasha; Balcerczyk, Aneta; Tang, Mimi L; El-Osta, Assam; Karagiannis, Tom C

    2012-07-15

    Histone deacetylase inhibitors (HDACIs) have emerged as a new class of anticancer therapeutics. The hydroxamic acid, suberoylanilide hydroxamic acid (Vorinostat, Zolinza™), and the cyclic peptide, depsipeptide (Romidepsin, Istodax™), were approved by the U.S. Food and Drug Administration (FDA) for the treatment of cutaneous T-cell lymphoma in 2006 and 2009, respectively. At least 15 HDACIs are currently undergoing clinical trials either alone or in combination with other therapeutic modalities for the treatment of numerous hematological and solid malignancies. The potential utility of HDACIs has been extended to nononcologic applications, including autoimmune disorders, inflammation, diseases of the central nervous system, and malaria. Given the promise of HDACIs, there is growing interest in the potential of dietary compounds that possess HDAC inhibition activity. This review is focused on the identification of and recent findings with HDACIs from dietary, medicinal plant, and microbial sources. We discuss the mechanisms of action and clinical potential of natural HDACIs. Apart from identification of further HDACI compounds from dietary sources, further research will be aimed at understanding the effects on gene regulation on lifetime exposure to these compounds. Another important issue that requires clarification.

  6. Hydrochemical and isotopic characteristics of estuarial seawater and river water of Bailanghe in Laizhou Bay, China

    Science.gov (United States)

    Yang, Qiaofeng; Xu, Suning; Wang, Ruijiu; Li, Wenpeng; Wang, Zhiyi; Mei, Junjun; Ding, Zhilei; Yang, Peijie; Yu, Liangju; Lv, Tieying; Bai, Gang; Kang, Wei

    2016-04-01

    In the study of seawater intrusion, seawater is usually taken as an end-member that mixes with other source(s). However, compared to standard seawater, the coastal seawater particularly that near the estuary, can be strongly influenced by the rivers into the sea and by coastal human activities. Their composition can be thus continuously changed and redistributed with space and time. Therefore, before investigating seawater intrusion in a certain area, it is essentially important to determine the features of the estuarine seawater (e.g. the mixture percentage between standard seawater and river water). In this study, we aimed to gain a clear situation of the seawater intrusion in Laizhou Bay, Southern Bohai, China. The issue aforementioned was investigated by comparing the stable isotopic and hydrochemical composition of the marine and river water collected in this area. Samples investigated include 5 surface water samples collected at the downstream of the Bailanghe and 7 seawater samples near the estuary of Laizhou Bay. Inert tracers (δD, δ18O, Cl, Br) and reaction tracers (Na, Mg, SO4, HCO3, Ca, NO3) are particularly analyzed. The major results are as follows: 1) All the river water samples fall below the Global Meteoric Water Line in the δD - δ18O diagram, reflecting evaporation of the upstream reservoir water. The seawater samples fall on the mixing line of standard seawater and the river water in the stable isotopic diagram. 2) The Cl-δ18O diagram indicates widespread dissolution of evaporate into the river, while high concentration of Ca and HCO3-, as well as the SO42- - Cl relation of the river water samples reflect the dissolution of CO2 , carbonate and sulfate in the atmosphere and on the ground. 3) The Br/Cl ratios of seawater samples are closed to the marine ratios. This together with the plots of major ions vs. Cl suggest that the seawater samples are originated from the mixture of standard seawater and river water. Therefore, when referring to the

  7. Microbial control of seawater by microfiltration

    Directory of Open Access Journals (Sweden)

    Wilmer Soler T

    2010-08-01

    Full Text Available Recent scientific literature presents seawater as a potential aid to solve a variety of health diseases in animals and human beings because by means of its mineral and trace elements content. In Colombia, Nicaragua and Spain it is collected in a natural way from de shore and drunk; however, this can represent a health risk because of the problems related to chemical and microbiological contamination. Microbial control of seawater allows the improvement of its microbiological quality. Objective: to compare the efficiency of three microbial control methods: microfiltration, solar exposition and quarantine. Methodology: 30 samples were collected in 20-liter high density polyethylene containers in three different places in the Colombian Atlantic coast. Results: 15 samples out of 30 showed the presence of bacteria such as E. coli and halophiles bacteria like Vibrio and Aeromonas. Microfiltration through ceramic filters of 0.5 µm produces disinfection in 100% of the samples but the quarantine for five months and solar disinfection are effective in 66 and 21% respectively. The latter requires certain weather conditions to achieve disinfection and it only allows managing small quantities of water. Dicussion: Considering chemical contamination in some places which cannot be controlled through disinfection methods, the collection of water offshore in clean places is suggested and then microfiltration treatment should be performed.

  8. Natural and Anthropogenic Influences on Atmospheric Aerosol Variability

    Energy Technology Data Exchange (ETDEWEB)

    Asmi, A.

    2012-07-01

    Aerosol particles are everywhere in the atmosphere. They are a key factor in many important processes in the atmosphere, including cloud formation, scattering of incoming solar radiation and air chemistry. The aerosol particles have relatively short lifetimes in lower atmosphere, typically from days to weeks, and thus they have a high spatial and temporal variability. This thesis concentrates on the extent and reasons of sub-micron aerosol particle variability in the lower atmosphere, using both global atmospheric models and analysis of observational data. Aerosol number size distributions in the lower atmosphere are affected strongly by the new particle formation. Perhaps more importantly, a strong influence new particle formation is also evident in the cloud condensation nuclei (CCN) concentrations, suggesting a major role of the sulphuric acid driven new particle formation in the climate system. In this thesis, the sub-micron aerosol number size distributions in the European regional background air were characterized for the first time from consistent, homogenized and comparable datasets. Some recent studies have suggested that differences in aerosol emissions between weekdays could also affect the weather via aerosol-cloud interactions. In this thesis, the weekday-to-weekday variation of CCN sized aerosol number concentrations in Europe were found to be much smaller than expected from earlier studies, based on particle mass measurements. This result suggests that a lack of week-day variability in meteorology is not necessarily a sign of weak aerosol-cloud interactions. An analysis of statistically significant trends in past decades of measured aerosol number concentrations from Europe, North America, Pacific islands and Antarctica generally show decreases in concentrations. The analysis of these changes show that a potential explanation for the decreasing trends is the general reduction of anthropogenic emissions, especially SO{sub 2}, although a combination of

  9. State of art and tendency of uranium extraction from seawater abroad

    International Nuclear Information System (INIS)

    Zhang Jinrui

    1995-01-01

    The amount of the natural resources in land is becoming smaller and smaller, and the people places hopes on the oceans. This paper describes and discusses the new achievements in the research of uranium extraction from seawater abroad

  10. Photolysis of 2,4,6-trinitrotoluene in seawater and estuary water: Impact of pH, temperature, salinity, and dissolved organic matter

    International Nuclear Information System (INIS)

    Luning Prak, Dianne J.; Breuer, James E.T.; Rios, Evelyn A.; Jedlicka, Erin E.; O'Sullivan, Daniel W.

    2017-01-01

    The influence of salinity, pH, temperature, and dissolved organic matter on the photolysis rate of 2,4,6-trinitrotoluene (TNT) in marine, estuary, and laboratory-prepared waters was studied using a Suntest CPS +® solar simulator equipped with optical filters. TNT degradation rates were determined using HPLC analysis, and products were identified using LC/MS. Minimal or no TNT photolysis occurred under a 395-nm long pass filter, but under a 295-nm filter, first-order TNT degradation rate constants and apparent quantum yields increased with increasing salinity in both natural and artificial seawater. TNT rate constants increased slightly with increasing temperature (10 to 32 °C) but did not change significantly with pH (6.4 to 8.1). The addition of dissolved organic matter (up to 5 mg/L) to ultrapure water, artificial seawater, and natural seawater increased the TNT photolysis rate constant. Products formed by TNT photolysis in natural seawater were determined to be 2,4,6-trinitrobenzaldehyde, 1,3,5-trinitrobenzene, 2,4,6-trinitrobenzoic acid, and 2-amino-4,6-dinitrobenzoic acid. - Highlights: • 2,4,6-trinitrotoluene (TNT) was photolyzed in marine, estuary, & laboratory waters. • TNT photolysis rates increased with increasing salinity & dissolved organic matter. • Temperature and pH had minimal impact on TNT photolysis in marine waters. • In seawater, TNT photolysis produced 1,3,5-trinitrobenzene & trinitrobenzaldehyde. • Polar products were 2,4,6-trinobenzoic acid & 2-amino-4,6-dinitrobenzoic acid.

  11. Symbiotic Role of the Viable but Nonculturable State of Vibrio fischeri in Hawaiian Coastal Seawater.

    Science.gov (United States)

    Lee, K; Ruby, E G

    1995-01-01

    To achieve functional bioluminescence, the developing light organ of newly hatched juveniles of the Hawaiian squid Euprymna scolopes must become colonized by luminous, symbiosis-competent Vibrio fischeri present in the ambient seawater. This benign infection occurs rapidly in animals placed in seawater from the host's natural habitat. Therefore, it was surprising that colony hybridization studies with a V. fischeri-specific luxA gene probe indicated the presence of only about 2 CFU of V. fischeri per ml of this infective seawater. To examine this paradox, we estimated the total concentration of V. fischeri cells present in seawater from the host's habitat in two additional ways. In the first approach, the total bacterial assemblage in samples of seawater was collected on polycarbonate membrane filters and used as a source of both a crude cell lysate and purified DNA. These preparations were then assayed by quantitative DNA-DNA hybridization with the luxA gene probe. The results suggested the presence of between 200 and 400 cells of V. fischeri per ml of natural seawater, a concentration more than 100 times that revealed by colony hybridization. In the second approach, we amplified V. fischeri-specific luxA sequences from microliter volumes of natural seawater by PCR. Most-probable-number analyses of the frequency of positive PCR results from cell lysates in these small volumes gave an estimate of the concentration of V. fischeri luxA gene targets of between 130 and 1,680 copies per ml. From these measurements, we conclude that in their natural seawater environment, the majority of V. fischeri cells become nonculturable while remaining viable and symbiotically infective. Experimental studies indicated that V. fischeri cells suspended in natural Hawaiian seawater enter such a state within a few days.

  12. Chemoreception of the Seagrass Posidonia Oceanica by Benthic Invertebrates is Altered by Seawater Acidification.

    Science.gov (United States)

    Zupo, Valerio; Maibam, Chingoileima; Buia, Maria Cristina; Gambi, Maria Cristina; Patti, Francesco Paolo; Scipione, Maria Beatrice; Lorenti, Maurizio; Fink, Patrick

    2015-08-01

    Several plants and invertebrates interact and communicate by means of volatile organic compounds (VOCs). These compounds may play the role of infochemicals, being able to carry complex information to selected species, thus mediating inter- or intra-specific communications. Volatile organic compounds derived from the wounding of marine diatoms, for example, carry information for several benthic and planktonic invertebrates. Although the ecological importance of VOCs has been demonstrated, both in terrestrial plants and in marine microalgae, their role as infochemicals has not been demonstrated in seagrasses. In addition, benthic communities, even the most complex and resilient, as those associated to seagrass meadows, are affected by ocean acidification at various levels. Therefore, the acidification of oceans could produce interference in the way seagrass-associated invertebrates recognize and choose their specific environments. We simulated the wounding of Posidonia oceanica leaves collected at two sites (a control site at normal pH, and a naturally acidified site) off the Island of Ischia (Gulf of Naples, Italy). We extracted the VOCs and tested a set of 13 species of associated invertebrates for their specific chemotactic responses in order to determine if: a) seagrasses produce VOCs playing the role of infochemicals, and b) their effects can be altered by seawater pH. Our results indicate that several invertebrates recognize the odor of wounded P. oceanica leaves, especially those strictly associated to the leaf stratum of the seagrass. Their chemotactic reactions may be modulated by the seawater pH, thus impairing the chemical communications in seagrass-associated communities in acidified conditions. In fact, 54% of the tested species exhibited a changed behavioral response in acidified waters (pH 7.7). Furthermore, the differences observed in the abundance of invertebrates, in natural vs. acidified field conditions, are in agreement with these behavioral

  13. Fast concentration of dissolved forms of cesium radioisotopes from large seawater samples

    International Nuclear Information System (INIS)

    Jan Kamenik; Henrieta Dulaiova; Ferdinand Sebesta; Kamila St'astna; Czech Technical University, Prague

    2013-01-01

    The method developed for cesium concentration from large freshwater samples was tested and adapted for analysis of cesium radionuclides in seawater. Concentration of dissolved forms of cesium in large seawater samples (about 100 L) was performed using composite absorbers AMP-PAN and KNiFC-PAN with ammonium molybdophosphate and potassium–nickel hexacyanoferrate(II) as active components, respectively, and polyacrylonitrile as a binding polymer. A specially designed chromatography column with bed volume (BV) 25 mL allowed fast flow rates of seawater (up to 1,200 BV h -1 ). The recovery yields were determined by ICP-MS analysis of stable cesium added to seawater sample. Both absorbers proved usability for cesium concentration from large seawater samples. KNiFC-PAN material was slightly more effective in cesium concentration from acidified seawater (recovery yield around 93 % for 700 BV h -1 ). This material showed similar efficiency in cesium concentration also from natural seawater. The activity concentrations of 137 Cs determined in seawater from the central Pacific Ocean were 1.5 ± 0.1 and 1.4 ± 0.1 Bq m -3 for an offshore (January 2012) and a coastal (February 2012) locality, respectively, 134 Cs activities were below detection limit ( -3 ). (author)

  14. Seawater sulfate reduction and sulfur isotope fractionation in basaltic systems: interaction of seawater with fayalite and magnetite at 200-3500C

    International Nuclear Information System (INIS)

    Shanks, W.C. III; Bischoff, J.L.; Rosenbauer, R.J.

    1981-01-01

    Sulfate reduction during seawater reaction with fayalite and with magnetite was rapid at 350 0 C, producing equilibrium assemblages of talc-pyrite-hematite-magnetite at low water/rock ratios and talc-pyrite-hematite-anhydrite at higher water/rock ratios. At 250 0 C, seawater reacting with fayalite produced detectable amounts of dissolved H 2 S. At 200 0 C, dissolved H 2 S was not detected, even after 219 days. Reaction stoichiometry indicates that sulfate reduction requires large amounts of H + , which, in subseafloor hydrothermal systems is provided by Mg metasomatism. Seawater contains sufficient Mg to supply all the H + necessary for quantitative reduction of seawater sulfate. Systematics of sulfur isotopes in the 250 and 350 0 C experiments indicate that isotopic equilibrium is reached and can be modeled as a Rayleigh distillation process. Isotopic composition of hydrothermally produced H 2 S in natural systems is strongly dependent upon the seawater/basalt ratio in the geothermal system, which controls the relative sulfide contributions from the two important sulfur sources, seawater sulfate and sulfide phases in basalt. Anhydrite precipitation during geothermal heating severely limits sulfate ingress into high temperature interaction zones. Quantitative sulfate reduction can thus be accomplished without producing strongly oxidized rocks and resultant sulfide sulfur isotope values represent a mixture of seawater and basaltic sulfur. (author)

  15. Seawater mesocosm experiments in the Arctic uncover differential transfer of marine bacteria to aerosols.

    Science.gov (United States)

    Fahlgren, Camilla; Gómez-Consarnau, Laura; Zábori, Julia; Lindh, Markus V; Krejci, Radovan; Mårtensson, E Monica; Nilsson, Douglas; Pinhassi, Jarone

    2015-06-01

    Biogenic aerosols critically control atmospheric processes. However, although bacteria constitute major portions of living matter in seawater, bacterial aerosolization from oceanic surface layers remains poorly understood. We analysed bacterial diversity in seawater and experimentally generated aerosols from three Kongsfjorden sites, Svalbard. Construction of 16S rRNA gene clone libraries from paired seawater and aerosol samples resulted in 1294 sequences clustering into 149 bacterial and 34 phytoplankton operational taxonomic units (OTUs). Bacterial communities in aerosols differed greatly from corresponding seawater communities in three out of four experiments. Dominant populations of both seawater and aerosols were Flavobacteriia, Alphaproteobacteria and Gammaproteobacteria. Across the entire dataset, most OTUs from seawater could also be found in aerosols; in each experiment, however, several OTUs were either selectively enriched in aerosols or little aerosolized. Notably, a SAR11 clade OTU was consistently abundant in the seawater, but was recorded in significantly lower proportions in aerosols. A strikingly high proportion of colony-forming bacteria were pigmented in aerosols compared with seawater, suggesting that selection during aerosolization contributes to explaining elevated proportions of pigmented bacteria frequently observed in atmospheric samples. Our findings imply that atmospheric processes could be considerably influenced by spatiotemporal variations in the aerosolization efficiency of different marine bacteria. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  16. Antibiotic resistance in Escherichia coli strains isolated from Antarctic bird feces, water from inside a wastewater treatment plant, and seawater samples collected in the Antarctic Treaty area

    Science.gov (United States)

    Rabbia, Virginia; Bello-Toledo, Helia; Jiménez, Sebastián; Quezada, Mario; Domínguez, Mariana; Vergara, Luis; Gómez-Fuentes, Claudio; Calisto-Ulloa, Nancy; González-Acuña, Daniel; López, Juana; González-Rocha, Gerardo

    2016-06-01

    Antibiotic resistance is a problem of global concern and is frequently associated with human activity. Studying antibiotic resistance in bacteria isolated from pristine environments, such as Antarctica, extends our understanding of these fragile ecosystems. Escherichia coli strains, important fecal indicator bacteria, were isolated on the Fildes Peninsula (which has the strongest human influence in Antarctica), from seawater, bird droppings, and water samples from inside a local wastewater treatment plant. The strains were subjected to molecular typing with pulsed-field gel electrophoresis to determine their genetic relationships, and tested for antibiotic susceptibility with disk diffusion tests for several antibiotic families: β-lactams, quinolones, aminoglycosides, tetracyclines, phenicols, and trimethoprim-sulfonamide. The highest E. coli count in seawater samples was 2400 cfu/100 mL. Only strains isolated from seawater and the wastewater treatment plant showed any genetic relatedness between groups. Strains of both these groups were resistant to β-lactams, aminoglycosides, tetracycline, and trimethoprim-sulfonamide.In contrast, strains from bird feces were susceptible to all the antibiotics tested. We conclude that naturally occurring antibiotic resistance in E. coli strains isolated from Antarctic bird feces is rare and the bacterial antibiotic resistance found in seawater is probably associated with discharged treated wastewater originating from Fildes Peninsula treatment plants.

  17. Determination of picomolar beryllium levels in seawater with inductively coupled plasma mass spectrometry following silica-gel preconcentration

    Energy Technology Data Exchange (ETDEWEB)

    Tazoe, Hirofumi, E-mail: tazoe@cc.hirosaki-u.ac.jp [Department of Radiation Chemistry, Institute of Radiation Emergency Mediation, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori 036-8564 (Japan); College of Humanities and Sciences, Nihon University, 3-25-40, Sakurajosui, Setagaya-ku, Tokyo 156-8550 (Japan); Yamagata, Takeyasu [College of Humanities and Sciences, Nihon University, 3-25-40, Sakurajosui, Setagaya-ku, Tokyo 156-8550 (Japan); Obata, Hajime [Atmosphere and Ocean Research Institute, The Tokyo University, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8564 (Japan); Nagai, Hisao [College of Humanities and Sciences, Nihon University, 3-25-40, Sakurajosui, Setagaya-ku, Tokyo 156-8550 (Japan)

    2014-12-10

    Highlights: • We developesd the simplest and robust SPE method for ultra low picomolar level beryllium in seawater. • Just silica gel column can quantitatively adsorb beryllium in neutral pH condition containing natural seawater. • EDTA solution can eliminate seawater matrixes retaining Be in the column, which optimize to ICP-MS detemination. • Accurate and precise Be data have been obtained for natural seawater from North Pacific Ocean. - Abstract: A robust and rapid method for the determination of natural levels of beryllium (Be) in seawater was developed to facilitate mapping Be concentrations in the ocean. A solid-phase extraction method using a silica gel column was applied for preconcentration and purification of Be in seawater prior to determination of Be concentrations with inductively coupled plasma mass spectrometry (ICP-MS). Be was quantitatively adsorbed onto silica gel from solutions with pH values ranging from 6.3 to 9, including natural seawater. The chelating agent ethylenediamine tetraacetic acid was used to remove other ions in the seawater matrix (Na, Mg, and Ca) that interfere with the ICP-MS analysis. The reproducibility of the method was 3% based on triplicate analyses of natural seawater samples, and the detection limit was 0.4 pmol kg{sup −1} for 250 mL of seawater, which is sufficient for the analysis of seawater in the open ocean. The method was then used to determine the vertical profile of Be in the eastern North Pacific Ocean, which was found to be a recycled-type profile in which the Be concentration increased with depth from the surface (7.2 pmol kg{sup −1} at <200 m) to deep water (29.2 pmol kg{sup −1} from 3500 m to the bottom)

  18. Determination of picomolar beryllium levels in seawater with inductively coupled plasma mass spectrometry following silica-gel preconcentration

    International Nuclear Information System (INIS)

    Tazoe, Hirofumi; Yamagata, Takeyasu; Obata, Hajime; Nagai, Hisao

    2014-01-01

    Highlights: • We developesd the simplest and robust SPE method for ultra low picomolar level beryllium in seawater. • Just silica gel column can quantitatively adsorb beryllium in neutral pH condition containing natural seawater. • EDTA solution can eliminate seawater matrixes retaining Be in the column, which optimize to ICP-MS detemination. • Accurate and precise Be data have been obtained for natural seawater from North Pacific Ocean. - Abstract: A robust and rapid method for the determination of natural levels of beryllium (Be) in seawater was developed to facilitate mapping Be concentrations in the ocean. A solid-phase extraction method using a silica gel column was applied for preconcentration and purification of Be in seawater prior to determination of Be concentrations with inductively coupled plasma mass spectrometry (ICP-MS). Be was quantitatively adsorbed onto silica gel from solutions with pH values ranging from 6.3 to 9, including natural seawater. The chelating agent ethylenediamine tetraacetic acid was used to remove other ions in the seawater matrix (Na, Mg, and Ca) that interfere with the ICP-MS analysis. The reproducibility of the method was 3% based on triplicate analyses of natural seawater samples, and the detection limit was 0.4 pmol kg −1 for 250 mL of seawater, which is sufficient for the analysis of seawater in the open ocean. The method was then used to determine the vertical profile of Be in the eastern North Pacific Ocean, which was found to be a recycled-type profile in which the Be concentration increased with depth from the surface (7.2 pmol kg −1 at <200 m) to deep water (29.2 pmol kg −1 from 3500 m to the bottom)

  19. Freeze desalination of seawater using LNG cold energy

    KAUST Repository

    Chang, Jian; Zuo, Jian; Lu, Kang-Jia; Chung, Neal Tai-Shung

    2016-01-01

    With the aid of cold energy from regasification of liquefied natural gas (LNG), freeze desalination (FD) is an emerging technology for seawater desalination because of its low energy characteristics and insensitivities to fouling problems. This work aims to investigate the major operating parameters of FD such as coolant temperature, freezing duration, supercooling, seeding, agitation, crystallizer material and subsequent washing procedure on ice production and water quality. It was found that the optimal freezing duration per batch was 1 h for an iron crystallizer and 1.5 h for a glass crystallizer. The optimal coolant temperature should be around −8 °C. The optimal amount of washing water to clean the raw ice was about 50 wt% of the raw ice. Over 50 wt% of the feed could be recovered as raw ice within 1 h, which means an overall ice recovery rate of higher than 25% (of the original seawater), considering the consumption of washing water. Both artificial and real seawater were tested under the optimized conditions. The total dissolved solid in the product ice was around 300 ppm, which met the World Health Organization (WHO) potable water salinity standard of 500 ppm. Therefore, the process parameters optimized in this study can be directly used for the freeze desalination of seawater.

  20. Freeze desalination of seawater using LNG cold energy

    KAUST Repository

    Chang, Jian

    2016-06-23

    With the aid of cold energy from regasification of liquefied natural gas (LNG), freeze desalination (FD) is an emerging technology for seawater desalination because of its low energy characteristics and insensitivities to fouling problems. This work aims to investigate the major operating parameters of FD such as coolant temperature, freezing duration, supercooling, seeding, agitation, crystallizer material and subsequent washing procedure on ice production and water quality. It was found that the optimal freezing duration per batch was 1 h for an iron crystallizer and 1.5 h for a glass crystallizer. The optimal coolant temperature should be around −8 °C. The optimal amount of washing water to clean the raw ice was about 50 wt% of the raw ice. Over 50 wt% of the feed could be recovered as raw ice within 1 h, which means an overall ice recovery rate of higher than 25% (of the original seawater), considering the consumption of washing water. Both artificial and real seawater were tested under the optimized conditions. The total dissolved solid in the product ice was around 300 ppm, which met the World Health Organization (WHO) potable water salinity standard of 500 ppm. Therefore, the process parameters optimized in this study can be directly used for the freeze desalination of seawater.

  1. Physiological indices of seawater readiness in postspawning steelhead kelts

    Science.gov (United States)

    Buelow, Jessica; Moffitt, Christine M.

    2015-01-01

    Management goals to improve the recovery of steelhead (Oncorhynchus mykiss) stocks at risk of extinction include increasing the proportion of postspawning fish that survive and spawn again. To be successful, postspawning steelhead (kelts) migrating downstream to the ocean must prepare physiologically and physically for a seawater transition. We sampled blood, gill filaments, and evaluated the external condition of migrating kelts from an ESA-listed population in the Snake/Columbia River system over two consecutive years to evaluate their physiological readiness for transition to seawater. We chose attributes often considered as measures of preparation for seawater in juveniles, including gill Na+,K+ ATPase activity, plasma electrolytes and hormones to consider factors related to external condition, size and sex. We found kelts in good external condition had plasma profiles similar to downstream-migrating smolts. In addition, we found more than 80% of kelts ranked in good external condition had smolt-like body silvering. We compared measures from migrating kelts with samples obtained from hatchery fish at the time of spawning to confirm that Na+, K+ ATPase activity in kelts was significantly elevated over spawning fish. We found significant differences in gill Na+, K+ ATPase activity in migrating kelts between the years of sampling, but little indication of influence of fish condition. We conclude that the postspawning steelhead sampled exhibited a suite of behaviours, condition and physiology characteristic of fish prepared for successful transition to a seawater environment.

  2. Rapid determination of 90Sr in seawater

    International Nuclear Information System (INIS)

    Pavlotskaya, F.I.; Moskin, A.I.

    1994-01-01

    A method for determining 90 Sr in seawater that is based on direct isolation and radiochemical purification of daughter 90 Y is proposed. The analysis time is 6-8 h. The chemical yield of the Y-carrier during the 90 Sr determination from 35 liters of seawater varies in the range 37-69%. The analysis uncertainty is 90 Sr from seawater and subsequent isolation of 90 Y

  3. Influence of anthropogenic transformation of Danube–Dniester interfluve on natural foci of tularaemia

    Directory of Open Access Journals (Sweden)

    I. T. Rusev

    2011-04-01

    Full Text Available The paper is devoted to the problem of occurrence of bacteria Francisella tularensis in steppe coastal zone of the Black Sea west part in the second half of XX century. The key factor decreasing the activity of tularaemia natural foci is anthropogenic influence. Resumed activity of natural foci appeared after implementation of big irrigation and drainage construction in former USSR – building of the Danube-Dniester-Dnepr irrigation system resulted in forming new environmental conditions as well as corridors for tularaemia distribution. The practical recommendation is to implement the eco-epizootological monitoring and to collect data for developing practical management of the natural foci of disease.

  4. Herbicide Persistence in Seawater Simulation Experiments.

    Directory of Open Access Journals (Sweden)

    Philip Mercurio

    Full Text Available Herbicides are detected year-round in marine waters, including those of the World Heritage listed Great Barrier Reef (GBR. The few previous studies that have investigated herbicide persistence in seawater generally reported half-lives in the order of months, and several studies were too short to detect significant degradation. Here we investigated the persistence of eight herbicides commonly detected in the GBR or its catchments in standard OECD simulation flask experiments, but with the aim to mimic natural conditions similar to those found on the GBR (i.e., relatively low herbicide concentrations, typical temperatures, light and microbial communities. Very little degradation was recorded over the standard 60 d period (Experiment 1 so a second experiment was extended to 365 d. Half-lives of PSII herbicides ametryn, atrazine, diuron, hexazinone and tebuthiuron were consistently greater than a year, indicating high persistence. The detection of atrazine and diuron metabolites and longer persistence in mercuric chloride-treated seawater confirmed that biodegradation contributed to the breakdown of herbicides. The shortest half-life recorded was 88 d for growth-regulating herbicide 2,4-D at 31°C in the dark, while the fatty acid-inhibitor metolachlor exhibited a minimum half-life of 281 d. The presence of moderate light and elevated temperatures affected the persistence of most of the herbicides; however, the scale and direction of the differences were not predictable and were likely due to changes in microbial community composition. The persistence estimates here represent some of the first appropriate data for application in risk assessments for herbicide exposure in tropical marine systems. The long persistence of herbicides identified in the present study helps explain detection of herbicides in nearshore waters of the GBR year round. Little degradation of these herbicides would be expected during the wet season with runoff and associated

  5. Herbicide Persistence in Seawater Simulation Experiments

    Science.gov (United States)

    Mercurio, Philip; Mueller, Jochen F.; Eaglesham, Geoff; Flores, Florita; Negri, Andrew P.

    2015-01-01

    Herbicides are detected year-round in marine waters, including those of the World Heritage listed Great Barrier Reef (GBR). The few previous studies that have investigated herbicide persistence in seawater generally reported half-lives in the order of months, and several studies were too short to detect significant degradation. Here we investigated the persistence of eight herbicides commonly detected in the GBR or its catchments in standard OECD simulation flask experiments, but with the aim to mimic natural conditions similar to those found on the GBR (i.e., relatively low herbicide concentrations, typical temperatures, light and microbial communities). Very little degradation was recorded over the standard 60 d period (Experiment 1) so a second experiment was extended to 365 d. Half-lives of PSII herbicides ametryn, atrazine, diuron, hexazinone and tebuthiuron were consistently greater than a year, indicating high persistence. The detection of atrazine and diuron metabolites and longer persistence in mercuric chloride-treated seawater confirmed that biodegradation contributed to the breakdown of herbicides. The shortest half-life recorded was 88 d for growth-regulating herbicide 2,4-D at 31°C in the dark, while the fatty acid-inhibitor metolachlor exhibited a minimum half-life of 281 d. The presence of moderate light and elevated temperatures affected the persistence of most of the herbicides; however, the scale and direction of the differences were not predictable and were likely due to changes in microbial community composition. The persistence estimates here represent some of the first appropriate data for application in risk assessments for herbicide exposure in tropical marine systems. The long persistence of herbicides identified in the present study helps explain detection of herbicides in nearshore waters of the GBR year round. Little degradation of these herbicides would be expected during the wet season with runoff and associated flood plumes

  6. Kinetics of ikaite precipitation and dissolution in seawater-derived brines at sub-zero temperatures to 265 K

    Science.gov (United States)

    Papadimitriou, Stathys; Kennedy, Hilary; Kennedy, Paul; Thomas, David N.

    2014-09-01

    The kinetics of calcium carbonate hexahydrate (ikaite) precipitation and dissolution were investigated in seawater and seawater-derived brines at sub-zero temperatures using the constant addition experimental technique. The steady state rate of these two processes was found to be a function of the deviation of the solution from equilibrium with respect to ikaite and conformed to the same empirical rate law as the anhydrous CaCO3 polymorphs, calcite and aragonite. In addition to the saturation state of the brine with respect to ikaite, the salinity of the brine and the temperature of the reaction evidently exerted some control on the ikaite precipitation kinetics, while the dissolution kinetics of the polymorph were not noticeably influenced by these two parameters. The experimental salinity and temperature conditions were equivalent to those at thermal equilibrium between brine and ice in the sea ice cover of polar seas. Simple modelling of the CO2 system by extrapolation of the oceanic equivalent to sea ice brines showed that the physical concentration of seawater ions and the changes in ikaite solubility as a function of salinity and temperature, both inherent in the sea ice system, would be insufficient to drive the emergent brines to ikaite supersaturation and precipitation in sea ice down to -8 °C. The loss of dissolved inorganic carbon to the gas phase of sea ice and to sympagic autotrophs are two independent mechanisms which, in nature, could prompt the brine CO2 system towards ikaite supersaturation and precipitation. Under these conditions, the steady state precipitation rate of ikaite was found to be fast enough for rapid formation within short time scales (days to weeks) in sea ice. The observed ikaite dissolution kinetics were also found conducive to short turn-over time scales of a few hours to a few days in corrosive solutions, such as surface seawater.

  7. Investigation on the effect of seawater to hydraulic property and wetting process of bentonite

    International Nuclear Information System (INIS)

    Hasegawa, Takuma

    2004-01-01

    On high-level waste disposal, bentonite is one of the most promising material for buffer and backfill material. The hydraulic properties and wetting process of bentonite are important not only for barrier performance assessment but also for prediction of waste disposal environment, such as resaturation time and thermal distribution. In Japan, we should consider the effect of seawater for bentonite, because radioactive waste will be disposed of in coastal area and in marine sediment where seawater remained. However, it is not enough to understand the effect of seawater. Therefore, experimental study was conducted to investigate the effect of seawater on the hydraulic conductivity and wetting process of bentonite. The effect of seawater on hydraulic conductivity is significant for Na-bentonite, the hydraulic conductivity of Na-bentonite in seawater is one order to magnitude higher than that in distilled water. On the other hand, the hydraulic conductivity of Ca-bentonite is not influenced by seawater. The hydraulic conductivity of bentonite decreases as effective montmorillonite density increases. The effective montmorillonite density is ratio between the weight of montmorillonite and volume of porosity and montmorillonite. The hydraulic conductivity of bentonite is close related to swelling property since the hydraulic conductivity decrease as the swelling pressure increase. Wetting process of compacted bentonite could be evaluated by diffusion phenomena since infiltration rate and change of saturation rate and represented by diffusion equation. The effect of seawater on water diffusivity is significant for Na-type bentonite with low effective montmorillonite density. Except for that condition, the water diffusivity of bentonite is almost constant and is not influenced by effective montmorillonite density and seawater. (author)

  8. The Influence of Documentary Films on 8th Grade Students' Views about Nature of Science

    Science.gov (United States)

    Seckin Kapucu, Munise; Cakmakci, Gultekin; Aydogdu, Cemil

    2015-01-01

    This quasi-experimental study aims to investigate the documentary films' influence on 8th grade students' nature of science views. The study's participants were 113 8th grade students from two different schools taught by two different teachers. The study was completed over a 6-week period, during which topics related to "Cell Division and…

  9. Exploring the Influence of Nature Relatedness and Perceived Science Knowledge on Proenvironmental Behavior

    Science.gov (United States)

    Obery, Amanda; Bangert, Arthur

    2017-01-01

    This study was undertaken to investigate the factors influencing proenvironmental behavior of individuals residing in the Northern Rocky Mountains (N = 267). Measures of relatedness to nature and perceived science knowledge were collected through a convenience sample approach using multiple avenues such as city email lists, organizational…

  10. The Nature and Correlates of Sibling Influence in Two-Parent African American Families

    Science.gov (United States)

    Whiteman, Shawn D.; Becerra Bernard, Julia M.; McHale, Susan M.

    2010-01-01

    Guided by research and theory on sibling similarities and differences, this study explored the nature and correlates of 2 processes of sibling influence--social learning and sibling differentiation--during adolescence. Participants included 2 adolescent-age siblings (M = 16.29 years for older siblings and M = 12.59 years for younger siblings,…

  11. Sulfide Production and Corrosion in Seawater During Exposure to FAME Alternative Fuel

    Science.gov (United States)

    2012-06-01

    transporting fatty acid methyl ester ( FAME ] alternative diesel fuel in contact with natural seawater under anaerobic conditions. Coastal Key West...Glycerol Fatty Acid Methyl Ester Exposure Chamber Anaerobic Chamber - bal. N2,10% H2, 0.1% C02 - maintain pH ~8 Polarization Resistance (Rp...and Corrosion in Seawater During Exposure to FAME Alternative Fuel Jason 5. Lee Richard I. Ray BrendaJ. Little Naval Research Laboratory Stennis

  12. Relative importance of natural and anthropogenic factors influencing karst rocky desertification

    Science.gov (United States)

    Xu, Erqi; Zhang, Hongqi

    2017-04-01

    As the most severe ecological issue in southwest China, karst rocky desertification (KRD) has both threatened and constrained regional sustainable development. Comprehensively understanding the relationship between the evolution of KRD and relevant driving data would provide more information to combat KRD in such complex karst environments. Past studies have been limited in quantifying the relative importance of driving factors influencing fine-scale KRD evolution, and have also lacked insight into their interactive impacts. To address these issues, we have used geographical information system techniques and a geographical detector model to explore the spatial consistency of driving factors and their interactions in relation to the evolution of KRD. Changshun County in China was selected as a representative area for the study. Nine relevant driving factors, including both natural and anthropogenic factors, were studied in regard to their relationships with KRD transformation between 2000 and 2010. Our results demonstrate the relative importance of driving data in influencing the improvement and deterioration of KRD. Lithology, soil type and road influence are identified as the leading factors. Interestingly, to our study at least, there is no significant difference between the impacts of natural and anthropogenic factors influencing KRD improvement, and even natural factors have a higher impact on KRD deterioration. Factors were found to enhance the influence of each other for KRD transformation. In particular, the results show a non-linearly enhanced effect between driving factors, which significantly aggravates KRD. New information found in our study helps to effectively control and restore areas afflicted by KRD.

  13. A field study of physico-chemical states of artificial radionuclides in seawater

    International Nuclear Information System (INIS)

    Nagaya, Yutaka; Nakamura, Kiyoshi

    1974-01-01

    The physico-chemical states of artificial radionuclides, 90 Sr, 137 Cs and 144 Ce in seawater were investigated by radiochemical analysis of filtered and unfiltered seawater. The difference of radionuclide concentrations between unfiltered and filtered seawaters was defined as the ''particulate form'' radioisotope and its ''particle ratio'' was discussed. Practically no particulate 90 Sr, greater than 0.22 μ in size, was observed in both coastal and open seawaters, but some of 137 Cs seemed to be insoluble in some circumstances, especially in coastal waters. A considerable amount of 144 Ce was found to be particulate. An estimation of the radionuclides in particulate form was made for Kashima-nada seawaters collected in 1970 to 1972, and it was shown that the possible occurrence of particulate radionuclides, greater than 0.22 μ in size, were 1% or less for 90 Sr and 6% for 137 Cs. In the coastal water, 80% of 144 Ce were seemed to be in particulate form, but in the open seawater only a few %. The influences of suspended materials to 137 Cs and 144 Ce concentration levels in seawater were not negligible and further investigations are desirable. (auth.)

  14. Primary biodegradation of petroleum hydrocarbons in seawater

    Energy Technology Data Exchange (ETDEWEB)

    Comber, M.I.H.; Den Haan, K.H.; Djemel, N.; Eadsforth, C.V.; King, D.; Paumen, M.L.; Parkerton, T.; Dmytrasz, B.

    2012-12-15

    This report describes primary biodegradation experiments performed to determine the persistence of higher molecular weight petroleum hydrocarbons in seawater. Results from the biodegradation experiments show that the majority of tested petroleum hydrocarbons have half-lives in seawater less than 60 days.

  15. Rapid determination of actinides in seawater samples

    International Nuclear Information System (INIS)

    Maxwell, S.L.; Culligan, B.K.; Hutchison, J.B.; Utsey, R.C.; McAlister, D.R.

    2014-01-01

    A new rapid method for the determination of actinides in seawater samples has been developed at the Savannah River National Laboratory. The actinides can be measured by alpha spectrometry or inductively-coupled plasma mass spectrometry. The new method employs novel pre-concentration steps to collect the actinide isotopes quickly from 80 L or more of seawater. Actinides are co-precipitated using an iron hydroxide co-precipitation step enhanced with Ti +3 reductant, followed by lanthanum fluoride co-precipitation. Stacked TEVA Resin and TRU Resin cartridges are used to rapidly separate Pu, U, and Np isotopes from seawater samples. TEVA Resin and DGA Resin were used to separate and measure Pu, Am and Cm isotopes in seawater volumes up to 80 L. This robust method is ideal for emergency seawater samples following a radiological incident. It can also be used, however, for the routine analysis of seawater samples for oceanographic studies to enhance efficiency and productivity. In contrast, many current methods to determine actinides in seawater can take 1-2 weeks and provide chemical yields of ∼30-60 %. This new sample preparation method can be performed in 4-8 h with tracer yields of ∼85-95 %. By employing a rapid, robust sample preparation method with high chemical yields, less seawater is needed to achieve lower or comparable detection limits for actinide isotopes with less time and effort. (author)

  16. The Influence of Safety, Efficacy, and Medical Condition Severity on Natural versus Synthetic Drug Preference.

    Science.gov (United States)

    Meier, Brian P; Lappas, Courtney M

    2016-11-01

    Research indicates that there is a preference for natural v. synthetic products, but the influence of this preference on drug choice in the medical domain is largely unknown. We present 5 studies in which participants were asked to consider a hypothetical situation in which they had a medical issue requiring pharmacological therapy. Participants ( N = 1223) were asked to select a natural, plant-derived, or synthetic drug. In studies 1a and 1b, approximately 79% of participants selected the natural v. synthetic drug, even though the safety and efficacy of the drugs were identical. Furthermore, participants rated the natural drug as safer than the synthetic drug, and as that difference increased, the odds of choosing the natural over synthetic drug increased. In studies 2 and 3, approximately 20% of participants selected the natural drug even when they were informed that it was less safe (study 2) or less effective (study 3) than the synthetic drug. Finally, in study 4, approximately 65% of participants chose a natural over synthetic drug regardless of the severity of a specific medical condition (mild v. severe hypertension), and this choice was predicted by perceived safety and efficacy differences. Overall, these data indicate that there is a bias for natural over synthetic drugs. This bias could have implications for drug choice and usage. © The Author(s) 2015.

  17. Sustainable and safe energy supply with seawater uranium fueled HTGR and its economy

    International Nuclear Information System (INIS)

    Fukaya, Y.; Goto, M.

    2017-01-01

    Highlights: • We discussed uranium resources with an energy security perspective. • We concluded seawater uranium is preferable for sustainability and energy security. • We evaluated electricity generation cost of seawater uranium fueled HTGR. • We concluded electricity generation with seawater uranium is reasonable. - Abstract: Sustainable and safe energy supply with High Temperature Gas-cooled Reactor (HTGR) fueled by uranium from seawater have been investigated and discussed. From the view point of safety feature of self-regulation with thermal reactor of HTGR, the uranium resources should be inexhaustible. The seawater uranium is expected to be alternative resources to conventional resources because it exists so much in seawater as a solute. It is said that 4.5 billion tons of uranium is dissolved in the seawater, which corresponds to a consumption of approximately 72 thousand years. Moreover, a thousand times of the amount of 4.5 trillion tU of uranium, which corresponds to the consumption of 72 million years, also is included in the rock on the surface of the sea floor, and that is also recoverable as seawater uranium because uranium in seawater is in an equilibrium state with that. In other words, the uranium from seawater is almost inexhaustible natural resource. However, the recovery cost with current technology is still expensive compared with that of conventional uranium. Then, we assessed the effect of increase in uranium purchase cost on the entire electricity generation cost. In this study, the economy of electricity generation of cost of a commercial HTGR was evaluated with conventional uranium and seawater uranium. Compared with ordinary LWR using conventional uranium, HTGR can generate electricity cheaply because of small volume of simple direct gas turbine system compared with water and steam systems of LWR, rationalization by modularizing, and high thermal efficiency, even if fueled by seawater uranium. It is concluded that the HTGR

  18. Development of radioactive seawater monitors, 1

    International Nuclear Information System (INIS)

    Fukushima, Masanori

    1989-01-01

    Applicability of some adsorptive materials to monitoring of radioactive seawater is generalized. Studied techniques that allow utilization of adsorptive materials in monitoring radioactive seawater are the substitute methods using sampled seawater or indicator plants such as gulfweed and the method using adsorptive materials for continuous monitoring of underwater radioactivity, the method using them for field measurement of under water radioactivity from a boat, and the method using an adsorptive material moored underwater for integration monitoring of underwater radioactivity. Selected adsorptive materials that were judged suitable for monitoring radioactive seawater is the one composed of some kind of adsorptive compound (manganese dioxide or ferrocyan cobalt potassium) fixed to crylic cellulose. This adsorptive material permits selective scavenging radioactive Cs, Mn, Co, Zn, Ce, Fe, Ru, Ra Th, Pu and Am from seawater. (aurhor)

  19. Mercury isotope signatures of seawater discharged from a coal-fired power plant equipped with a seawater flue gas desulfurization system.

    Science.gov (United States)

    Lin, Haiying; Peng, Jingji; Yuan, Dongxing; Lu, Bingyan; Lin, Kunning; Huang, Shuyuan

    2016-07-01

    Seawater flue gas desulfurization (SFGD) systems are commonly used to remove acidic SO2 from the flue gas with alkaline seawater in many coastal coal-fired power plants in China. However, large amount of mercury (Hg) originated from coal is also transferred into seawater during the desulfurization (De-SO2) process. This research investigated Hg isotopes in seawater discharged from a coastal plant equipped with a SFGD system for the first time. Suspended particles of inorganic minerals, carbon residuals and sulfides are enriched in heavy Hg isotopes during the De-SO2 process. δ(202)Hg of particulate mercury (PHg) gradually decreased from -0.30‰ to -1.53‰ in study sea area as the distance from the point of discharge increased. The results revealed that physical mixing of contaminated De-SO2 seawater and uncontaminated fresh seawater caused a change in isotopic composition of PHg isotopes in the discharging area; and suggested that both De-SO2 seawater and local background contributed to PHg. The impacted sea area predicted with isotopic tracing technique was much larger than that resulted from a simple comparison of pollutant concentration. It was the first attempt to apply mercury isotopic composition signatures with two-component mixing model to trace the mercury pollution and its influence in seawater. The results could be beneficial to the coal-fired plants with SFGD systems to assess and control Hg pollution in sea area. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. How daylight influences high-order chromatic descriptors in natural images.

    Science.gov (United States)

    Ojeda, Juan; Nieves, Juan Luis; Romero, Javier

    2017-07-01

    Despite the global and local daylight changes naturally occurring in natural scenes, the human visual system usually adapts quite well to those changes, developing a stable color perception. Nevertheless, the influence of daylight in modeling natural image statistics is not fully understood and has received little attention. The aim of this work was to analyze the influence of daylight changes in different high-order chromatic descriptors (i.e., color volume, color gamut, and number of discernible colors) derived from 350 color images, which were rendered under 108 natural illuminants with Correlated Color Temperatures (CCT) from 2735 to 25,889 K. Results suggest that chromatic and luminance information is almost constant and does not depend on the CCT of the illuminant for values above 14,000 K. Nevertheless, differences between the red-green and blue-yellow image components were found below that CCT, with most of the statistical descriptors analyzed showing local extremes in the range 2950 K-6300 K. Uniform regions and areas of the images attracting observers' attention were also considered in this analysis and were characterized by their patchiness index and their saliency maps. Meanwhile, the results of the patchiness index do not show a clear dependence on CCT, and it is remarkable that a significant reduction in the number of discernible colors (58% on average) was found when the images were masked with their corresponding saliency maps. Our results suggest that chromatic diversity, as defined in terms of the discernible colors, can be strongly reduced when an observer scans a natural scene. These findings support the idea that a reduction in the number of discernible colors will guide visual saliency and attention. Whatever the modeling is mediating the neural representation of natural images, natural image statistics, it is clear that natural image statistics should take into account those local maxima and minima depending on the daylight illumination and

  1. Automated nutrient analyses in seawater

    Energy Technology Data Exchange (ETDEWEB)

    Whitledge, T.E.; Malloy, S.C.; Patton, C.J.; Wirick, C.D.

    1981-02-01

    This manual was assembled for use as a guide for analyzing the nutrient content of seawater samples collected in the marine coastal zone of the Northeast United States and the Bering Sea. Some modifications (changes in dilution or sample pump tube sizes) may be necessary to achieve optimum measurements in very pronounced oligotrophic, eutrophic or brackish areas. Information is presented under the following section headings: theory and mechanics of automated analysis; continuous flow system description; operation of autoanalyzer system; cookbook of current nutrient methods; automated analyzer and data analysis software; computer interfacing and hardware modifications; and trouble shooting. The three appendixes are entitled: references and additional reading; manifold components and chemicals; and software listings. (JGB)

  2. Why do local communities support or oppose seawater desalination?

    Science.gov (United States)

    Mirza Ordshahi, B.; Heck, N.; Faraola, S.; Paytan, A.; Haddad, B.; Potts, D. C.

    2016-12-01

    Freshwater shortages have become a global problem due to increasing water consumption and environmental changes which are reducing the reliability of traditional water resources. One option to address water shortages in coastal areas is the use of seawater desalination. Desalination technology is particularly valued for the production of high quality drinking water and consistent production. However, seawater desalination is controversial due to potential environmental, economic, and societal impacts and lack of public support for this water supply method. Compared to alternative potable water production methods, such as water recycling, little is known about public attitudes towards seawater desalination and factors that shape local support or rejection. Our research addresses this gap and explores variables that influence support for proposed desalination plants in the Monterey Bay region, where multiple facilities have been proposed in recent years. Data was collected via a questionnaire-based survey among a random sample of coastal residents and marine stakeholders between June-July, 2016. Findings of the study identify the influence of socio-demographic variables, knowledge about desalination, engagement in marine activities, perception of the environmental context, and the existence of a National Marine Sanctuary on local support. Research outcome provide novel insights into public attitudes towards desalination and enhances our understanding of why communities might support or reject this water supply technology.

  3. Cytoplasmic genetic variation and extensive cytonuclear interactions influence natural variation in the metabolome

    DEFF Research Database (Denmark)

    Joseph, Bindu; Corwin, Jason A.; Li, Baohua

    2013-01-01

    Understanding genome to phenotype linkages has been greatly enabled by genomic sequencing. However, most genome analysis is typically confined to the nuclear genome. We conducted a metabolomic QTL analysis on a reciprocal RIL population structured to examine how variation in the organelle genomes...... was a central hub in the epistatic network controlling the plant metabolome. This epistatic influence manifested such that the cytoplasmic background could alter or hide pairwise epistasis between nuclear loci. Thus, cytoplasmic genetic variation plays a central role in controlling natural variation...... in metabolomic networks. This suggests that cytoplasmic genomes must be included in any future analysis of natural variation....

  4. Bicarbonate Elution of Uranium from Amidoxime-Based Polymer Adsorbents for Sequestering Uranium from Seawater

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Horng-Bin [Department of Chemistry, University of Idaho, Moscow, Idaho 83844 USA; Wai, Chien M. [Department of Chemistry, University of Idaho, Moscow, Idaho 83844 USA; Kuo, Li-Jung [Pacific Northwest National Laboratory, Marine Sciences Laboratory, Sequim, Washington 98382 USA; Gill, Gary [Pacific Northwest National Laboratory, Marine Sciences Laboratory, Sequim, Washington 98382 USA; Tian, Guoxin [Lawrence Berkeley National Laboratory, Berkeley, California 94720 USA; Rao, Linfeng [Lawrence Berkeley National Laboratory, Berkeley, California 94720 USA; Das, Sadananda [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 USA; Mayes, Richard T. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 USA; Janke, Christopher J. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 USA

    2017-05-02

    Uranium adsorbed on amidoxime-based polyethylene fibers in simulated seawater can be quantitatively eluted using 3 M KHCO3 at 40°C. Thermodynamic calculations are in agreement with the experimental observation that at high bicarbonate concentrations (3 M) uranyl ions bound to amidoxime molecules are converted to uranyl tris-carbonato complex in the aqueous solution. The elution process is basically the reverse reaction of the uranium adsorption process which occurs at a very low bicarbonate concentration (~10-3 M) in seawater. In real seawater experiments, the bicarbonate elution is followed by a NaOH treatment to remove natural organic matter adsorbed on the polymer adsorbent. Using the sequential bicarbonate and NaOH elution, the adsorbent is reusable after rinsing with deionized water and the recycled adsorbent shows no loss of uranium loading capacity based on real seawater experiments.

  5. The status quo and the prospect of extraction of resources in seawater

    International Nuclear Information System (INIS)

    Katoh, Shunsaku

    1991-01-01

    Sea is the natural storage, and the enormous quantity of river water which contains the large amount of ions and compositions flows into sea, accordingly it has been calculated that seawater is replaced with new water in about 4 x 10 4 years. Sea is always agitated by tidal current, therefore, the composition of seawater is nearly uniform in most sea areas. Almost all elements existing in nature are dissolved in seawater, and the state of dissolution of main elements and their concentration are shown. The total quantity of seawater is as enormous as 1.35 x 10 9 km 3 , accordingly even in the trace elements in seawater, the total dissolved amount is enormous. For Japan which lacks resources, it is the important subject to develop the technology of effectively utilizing the resources in sea. The methods of obtaining sodium chloride, magnesium, bromine and potassium, which are the main components of seawater, are briefly explained. As the extraction of trace components, gold and silver, uranium, lithium, boron, strontium, vanadium, molybdenum, yttrium and heavy water are taken up. The optimal system must be built including the development of high performance adsorbents. (K.I.)

  6. The influence of calcium magnesium, and sodium on the spectrographic analysis of natural waters

    International Nuclear Information System (INIS)

    Diaz Guerra, J. P.; Capdevilla, C.

    1969-01-01

    The influences of 1000 μg/ml of calcium and sodium and 300 μg/ml of magnesium, on the spectrographic determination of Al, Ba, Cr, Fe, Li , Mn, Ni, Pb, Sr and Ti, minor constituents in natural waters, have been studied, In order to eliminate them, the elements Ga, In, La, Ti and Zn, as well as a mixture containing 30 % Tl-70 % In, have been tested as spectrochemical buffers. (Author) 7 refs

  7. Three-dimensional numerical simulation of natural convection under the influence of magnetic fields

    International Nuclear Information System (INIS)

    Moessner, R.

    1996-04-01

    This report deals with the influence of strong magnetic fields on three-dimensional natural convection. First the dimensionless basic equations are derived in cartesian coordinates. This equations are solved numerically in rectangular domains with a Finite-Difference-Method. The following calculations investigate the flow in an electrically insulated cube which is heated and cooled at side walls. It is possible to perform systematic computations for the variation of the direction of the magnetic field and thermal boundary conditions. (orig.)

  8. Preparation of Pt deposited nanotubular TiO2 as cathodes for enhanced photoelectrochemical hydrogen production using seawater electrolytes

    International Nuclear Information System (INIS)

    Nam, Wonsik; Oh, Seichang; Joo, Hyunku; Yoon, Jaekyung

    2011-01-01

    The purpose of this study was to develop effective cathodes to increase the production of hydrogen and use the seawater, an abundant resource in the earth as the electrolyte in photoelectrochemical systems. In order to fabricate the Pt/TiO 2 cathodes, various contents of the Pt precursor (0-0.4 wt%) deposited by the electrodeposition method were used. On the basis of the hydrogen evolution rate, 0.2 wt% Pt/TiO 2 was observed to exhibit the best performance among the various Pt/TiO 2 cathodes with the natural seawater and two concentrated seawater electrolytes obtained from single (nanofiltration) and combined membrane (nanofiltration and reverse osmosis) processes. The surface characterizations exhibited that crystal structures and morphological properties of Pt and TiO 2 found the results of XRD pattern and SEM/TEM images, respectively. - Graphical abstract: On the basis of photoelectrochemical hydrogen production, 0.2 wt% Pt/TiO 2 was observed to exhibit the best performance among the various Pt/TIO 2 cathodes with natural seawater. In comparison of hydrogen evolution rate with various seawater electrolytes, 0.2 wt% Pt/TiO 2 was found to show the better performance as cathode with the concentrated seawater electrolytes obtained from membrane. Highlights: → Pt deposited TiO 2 electrodes are used as cathode in PEC H 2 production. → Natural and concentrated seawater by membranes are used as electrolytes in PEC. → Pt/TiO 2 shows a good performance as cathode with seawater electrolytes. → H 2 evolution rate increases with more concentrated seawater electrolyte. → Highly saline seawater is useful resource for H 2 production.

  9. CONSIDERATIONS REGARDING THE INFLUENCE OF LEGAL COMMUNICATION FROM THE PERSPECTIVE OF NATURAL LAW

    Directory of Open Access Journals (Sweden)

    Claudiu Ramon D. BUTCULESCU

    2016-05-01

    Full Text Available This article addresses the issue of legal communication within natural law. Law has an important role, in relation to civilization and legal culture and one of the means through which law influences both culture and civilization is legal communication. The patterns of legal communication should be analyzed from the perspective of all important schools of legal thought: natural law, legal positivism, historical school of law etc. In this paper, the perception of law, through legal communication, within natural law is discussed and analyzed, from the principles and statements of Aristotle to the writings of St. Bernard of Clairvaux, St. Thomas Aquinas and later to the theories of Hugo Grotius. This study also aims to prove that the difference between legal communication within the major schools of legal thought does not regard the essence of communication or the various principles of law, but merely the perception of law, which varies from one school of thought to another.

  10. Present status of uranium extraction from seawater

    International Nuclear Information System (INIS)

    Kusakabe, Katsuki; Morooka, Shigeharu

    1993-01-01

    For the research on the extraction of uranium from seawater, various processes have been examined, but the most promising process is adsorption. Its key point is the performance of the adsorbent. The system as compact as possible, in which a large quantity of seawater effectively contacts with the adsorbent, must be constructed economically. As the inorganic adsorbent, titanium oxide is the best, but organic amidoxime is superior to it. The present state of the development of the adsorbent, the rate of adsorption of the adsorbenbt, the seawater uranium adsorption system and the experiment in Imari Bay are reported. (K.I.)

  11. Transformation processes influencing physico-chemical forms of radionuclides and trace elements in natural water systems

    International Nuclear Information System (INIS)

    Salbu, B.; Riise, G.; Oughton, D.H.

    1995-01-01

    In order to assess short and long term consequences of radionuclides and trace elements introduced to aquatic systems, knowledge on source terms, key factors and key processes influencing the speciation is essential. The mobility, bioavailability and subsequent transfer into food chains depend on the physico-chemical forms on radionuclides and trace metals. In addition, transformation processes and especially the interaction with natural organic matter (NOM) influences the distribution pattern. Furthermore, the prevailing climate conditions, e.g. episodic events and temperature are vital for fluxes and for the kinetics of the transformation processes. In the present work processes in catchments and processes associated with acidification, episodic events, climate conditions (temperature) and mixing zone phenomena influencing the speciation of radionuclides and trace metals are highlighted. These processes should be highly relevant for assessing far field consequences of radionuclides potentially released from disposal sites. (authors). 21 refs., 8 figs., 1 tab

  12. Hysteretic behavior in seawater intrusion in response to discontinuous drought periods

    Science.gov (United States)

    Salandin, P.; Darvini, G.

    2017-12-01

    The seawater intrusion (SWI) represents a relevant problem for communities living in many coastal regions and in small islands, where the amount of fresh water available for human consumption or irrigation purposes depends on the equilibrium between the natural groundwater recharge from precipitations and the surrounding sea. This issue is exacerbated by climate changes, and, as a consequence, the reduction of natural groundwater recharge and the decrease the seaward flows of fresh water rather than sea level rise, as recently demonstrated by Ketabchi et al. (2016), leads to magnify the seawater intrusion into coastal aquifers. The temporal fluctuation of the fresh water table level are a natural consequence of the interaction of the aquifer with a water body or due to the seasonal replenishment of the water table. The severe and prolonged drought phenomena as that observed in last years in some areas of the Mediterranean, as over the central western Mediterranean basin, Italy and Spain, where a decreasing trend in total precipitation was detected (Alpert et al., 2002) in addition to the rise in temperature, enlarges the variation of the freshwater flux and can magnify the progression of the saline wedge. In the present study we demonstrate that the presence of varying boundary constraints or forcing factors may lead to hysteretic behavior in saltwater intrusion, showing dependence of the saline wedge on historic conditions. Therefore, the dynamic behavior of SWI may depend on both the present and past forcing conditions. To this aim different transient simulations supported by evidences deduced from a physical model are carried out to assess the presence of the hysteretic effects in the SWI phenomenon and to evaluate its influence in the management of the coastal aquifers for both the rational exploitation and the corrected management of water resources. About 70% of the world's population dwells in coastal zones. Therefore the optimal exploitation of fresh

  13. Influence of natural zeolite and nitrification inhibitor on organics degradation and nitrogen transformation during sludge composting.

    Science.gov (United States)

    Zhang, Junya; Sui, Qianwen; Li, Kun; Chen, Meixue; Tong, Juan; Qi, Lu; Wei, Yuansong

    2016-01-01

    Sludge composting is one of the most widely used treatments for sewage sludge resource utilization. Natural zeolite and nitrification inhibitor (NI) are widely used during composting and land application for nitrogen conservation, respectively. Three composting reactors (A--the control, B--natural zeolite addition, and C--3,4-dimethylpyrazole phosphate (DMPP) addition) were established to investigate the influence of NI and natural zeolite addition on organics degradation and nitrogen transformation during sludge composting conducted at the lab scale. The results showed that, in comparison with the control, natural zeolite addition accelerated organics degradation and the maturity of sludge compost was higher, while the DMPP addition slowed down the degradation of organic matters. Meanwhile, the nitrogen transformation functional genes including those responses for nitrification (amoA and nxrA) and denitrification (narG, nirS, nirK, and nosZ) were quantified through quantitative PCR (qPCR) to investigate the effects of natural zeolites and DMPP addition on nitrogen transformation. Although no significant difference in the abundance of nitrogen transformation functional genes was observed between treatments, addition of both natural zeolite and DMPP increases the final total nitrogen content by 48.6% and 23.1%, respectively. The ability of natural zeolite for nitrogen conservation was due to the absorption of NH3 by compost, and nitrogen conservation by DMPP was achieved by the source reduction of denitrification. Besides, it was assumed that the addition of natural zeolite and DMPP may affect the activity of these genes instead of the abundance.

  14. Marshes on the Move: Testing effects of seawater intrusion on ...

    Science.gov (United States)

    The Northeastern United States is a hotspot for sea level rise (SLR), subjecting coastal salt marshes to erosive loss, shifts in vegetation communities, and altered biogeochemistry due to seawater intrusion. Salt marsh plant community zonation is driven by tradeoffs in stress tolerance and interspecific interactions. As seawater inundates progressively higher marsh elevations, shifts in marsh vegetation communities landward may herald salt marsh “migration”, which could allow continuity of marsh function and ecosystem service provision. To elucidate possible effects of seawater intrusion on marsh-upland edge plant communities, a space-for-time approach was replicated at two Rhode Island salt marshes. At each site, peat blocks (0.5 m x 0.5 m x 0.5 m, n=6) with intact upland-marsh edge vegetation were transplanted downslope into the regularly-inundated mid-marsh. Procedural controls (n=3) were established at each elevation by removing and replacing peat blocks, and natural controls (n=3) consisted of undisturbed plots. During peak productivity, each plot was assessed for species composition, percent cover and average height. Results demonstrate stunting of marsh-upland edge vegetation in response to increased inundation, and the beginnings of colonization of the transplanted plots by salt marsh species. The extent of colonization differed between the two sites, suggesting that site-specific factors govern vegetation responses to increased inundation.

  15. The Geologic History of Seawater

    Science.gov (United States)

    Holland, H. D.

    2003-12-01

    Aristotle proposed that the saltness of the sea was due to the effect of sunlight on water. Robert Boyle took strong exception to this view and - in the manner of the Royal Society - laid out a program of research in the opening paragraph of his Observations and Experiments about the Saltness of the Sea (1674) (Figure 1): (20K)Figure 1. Title page of Robert Boyle's Tracts consisting of Observations about the Saltness of the Sea and other essays (1674). The Cause of the Saltness of the Sea appears by Aristotle's Writings to have busied the Curiosity of Naturalists before his time; since which, his Authority, perhaps much more than his Reasons, did for divers Ages make the Schools and the generality of Naturalists of his Opinion, till towards the end of the last Century, and the beginning of ours, some Learned Men took the boldness to question the common Opinion; since when the Controversie has been kept on foot, and, for ought I know, will be so, as long as ‘tis argued on both sides but by Dialectical Arguments, which may be probable on both sides, but are not convincing on either. Wherefore I shall here briefly deliver some particulars about the Saltness of the Sea, obtained by my own trials, where I was able; and where I was not, by the best Relations I could procure, especially from Navigators.Boyle measured and compiled a considerable set of data for variations in the saltness of surface seawater. He also designed an improved piece of equipment for sampling seawater at depth, but the depths at which it was used were modest: 30 m with his own instrument, 80 m with another, similar sampler. However, the younger John Winthrop (1606-1676), an early member of the Royal Society, an important Governor of Connecticut, and a benefactor of Harvard College, was asked to collect seawater from the bottom of the Atlantic Ocean during his crossing from England to New England in the spring of 1663. The minutes of the Royal Society's meeting on July 20, 1663, give the

  16. Seawater circulating system in an aquaculture laboratory

    Digital Repository Service at National Institute of Oceanography (India)

    Chatterji, A.; Ingole, B.S.; Parulekar, A.H.

    The note gives an account, for the first time in India, of an Aquaculture Laboratory with open type seawater circulating system developed at the National Institute of Oceanography, Goa, India. Besides describing the details of the system...

  17. Seawater Immersion of GEM II Propellant

    National Research Council Canada - National Science Library

    Merrill, Calude

    1999-01-01

    ... (% AP lost/week aged in seawater) and intercepts that depend on sample size. Friction and impact data on dried aged propellant samples showed no increased burning hazard compared with propellant not exposed to water...

  18. Uranium preconcentration from seawater using adsorptive membranes

    International Nuclear Information System (INIS)

    Das, Sadananda; Pandey, A.K.; Manchanda, V.K.; Athawale, A.A.

    2009-01-01

    Uranium recovery from bio-aggressive but lean feed like seawater is a challenging problem as it requires in situ preconcentration of uranium in presence of huge excess of competing ions with fast sorption kinetics. In our laboratory, widely used amidoxime membrane (AO-membrane) was evaluated for uranium sorption under seawater conditions. This study indicated that AO-membrane was inherently slow because of the complexation chemistry involved in transfer of U(VI) from (UO 2 (CO 3 ) 3 ) 4 - to AO sites in membrane. In order to search better options, several chemical compositions of membrane were scanned for their efficacy for uranium preconcentration from seawater, and concluded that EGMP-membrane offers several advantages over AO-membrane. In this paper, the comparison of EGMP-membrane with AO-membrane for uranium sorption under seawater conditions has been reviewed. (author)

  19. Influence of emulsion nature on radiation response of β-carotene in an aqueous medium

    International Nuclear Information System (INIS)

    Bhushan, B.; Tobback, P.; Snauwaert, F.; Maes, E.

    1978-01-01

    The radiation response of β-carotene was followed in lipid solvents and in aqueous preparations. The nature of the solvent was found to have a marked influence on the response of β-carotene to γ-radiation. In aqueous emulsions radiation destruction of β-carotene was far less than that observed in solutions. Oil in water (O/W) emulsions of petroleum ether offered maximum protection to β-carotene against radiation damage. This observation was attributed to the multiphase nature of the emulsion since a transparent aqueous preparation was observed to offer no protection upon irradiation. Solubility of crystalline β-carotene in water was found to increase with the emulsifier concentration. Irradiation revealed that the extent of β-carotene destruction was dose dependent and increased with the solubility of β-carotene in water. In the presence of a free radical scavenger DPPH β-carotene exhibited varied radiation response depending upon the nature of solvents used. Thus, in transparent aqueous preparations the protection afforded by added DPPH to β-carotene was almost complete, while its influence was insignificant in O/W emulsions. The significance of these observations in radiation processing of foods is discussed. (author)

  20. Extraction of uranium from seawater: chemical process and plant design feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, M.H.; Frame, J.M.; Dudey, N.D.; Kiel, G.R.; Mesec, V.; Woodfield, F.W.; Binney, S.E.; Jante, M.R.; Anderson, R.C.; Clark, G.T.

    1979-02-01

    A major assessment was made of the uranium resources in seawater. Several concepts for moving seawater to recover the uranium were investigated, including pumping the seawater and using natural ocean currents or tides directly. The optimal site chosen was on the southeastern Puerto Rico coast, with the south U.S. Atlantic coast as an alternate. The various processes for extracting uranium from seawater were reviewed, with the adsorption process being the most promising at the present time. Of the possible adsorbents, hydrous titanium oxide was found to have the best properties. A uranium extraction plant was conceptually designed. Of the possible methods for contacting the seawater with the adsorbent, a continuous fluidized bed concept was chosen as most practical for a pumped system. A plant recovering 500 tonnes of U/sub 3/O/sub 8/ per year requires 5900 cubic meters per second of seawater to be pumped through the adsorbent beds for a 70% overall recovery efficiency. Total cost of the plant was estimated to be about $6.2 billion. A computer model for the process was used for parametric sensitivity studies and economic projections. Several design case variations were developed. Other topics addressed were the impact of co-product recovery, environmental considerations, etc.

  1. Extraction of uranium from seawater: chemical process and plant design feasibility study

    International Nuclear Information System (INIS)

    Campbell, M.H.; Frame, J.M.; Dudey, N.D.; Kiel, G.R.; Mesec, V.; Woodfield, F.W.; Binney, S.E.; Jante, M.R.; Anderson, R.C.; Clark, G.T.

    1979-02-01

    A major assessment was made of the uranium resources in seawater. Several concepts for moving seawater to recover the uranium were investigated, including pumping the seawater and using natural ocean currents or tides directly. The optimal site chosen was on the southeastern Puerto Rico coast, with the south U.S. Atlantic coast as an alternate. The various processes for extracting uranium from seawater were reviewed, with the adsorption process being the most promising at the present time. Of the possible adsorbents, hydrous titanium oxide was found to have the best properties. A uranium extraction plant was conceptually designed. Of the possible methods for contacting the seawater with the adsorbent, a continuous fluidized bed concept was chosen as most practical for a pumped system. A plant recovering 500 tonnes of U 3 O 8 per year requires 5900 cubic meters per second of seawater to be pumped through the adsorbent beds for a 70% overall recovery efficiency. Total cost of the plant was estimated to be about $6.2 billion. A computer model for the process was used for parametric sensitivity studies and economic projections. Several design case variations were developed. Other topics addressed were the impact of co-product recovery, environmental considerations, etc

  2. Responses of an Agricultural Soil Microbiome to Flooding with Seawater after Managed Coastal Realignment

    Directory of Open Access Journals (Sweden)

    Kamilla S. Sjøgaard

    2018-01-01

    Full Text Available Coastal areas have become more prone to flooding with seawater due to climate-change-induced sea-level rise and intensified storm surges. One way to cope with this issue is by “managed coastal realignment”, where low-lying coastal areas are no longer protected and instead flooded with seawater. How flooding with seawater impacts soil microbiomes and the biogeochemical cycling of elements is poorly understood. To address this, we conducted a microcosm experiment using soil cores collected at the nature restoration project site Gyldensteen Strand (Denmark, which were flooded with seawater and monitored over six months. Throughout the experiment, biogeochemical analyses, microbial community fingerprinting and the quantification of marker genes documented clear shifts in microbiome composition and activity. The flooding with seawater initially resulted in accelerated heterotrophic activity that entailed high ammonium production and net removal of nitrogen from the system, also demonstrated by a concurrent increase in the abundances of marker genes for ammonium oxidation and denitrification. Due to the depletion of labile soil organic matter, microbial activity decreased after approximately four months. The event of flooding caused the largest shifts in microbiome composition with the availability of labile organic matter subsequently being the most important driver for the succession in microbiome composition in soils flooded with seawater.

  3. Differential utility of the Bacteroidales DNA and RNA markers in the tiered approach for microbial source tracking in subtropical seawater.

    Science.gov (United States)

    Liu, Rulong; Cheng, Ken H F; Wong, Klaine; Cheng, Samuel C S; Lau, Stanley C K

    2015-07-01

    Source tracking of fecal pollution is an emerging component in water quality monitoring. It may be implemented in a tiered approach involving Escherichia coli and/or Enterococcus spp. as the standard fecal indicator bacteria (FIB) and the 16S rRNA gene markers of Bacteroidales as source identifiers. The relative population dynamics of the source identifiers and the FIB may strongly influence the implementation of such approach. Currently, the relative performance of DNA and RNA as detection targets of Bacteroidales markers in the tiered approach is not known. We compared the decay of the DNA and RNA of the total (AllBac) and ruminant specific (CF128) Bacteroidales markers with those of the FIB in seawater spiked with cattle feces. Four treatments of light and oxygen availability simulating the subtropical seawater of Hong Kong were tested. All Bacteroidales markers decayed significantly slower than the FIB in all treatments. Nonetheless, the concentrations of the DNA and RNA markers and E. coli correlated significantly in normoxic seawater independent of light availability, and in hypoxic seawater only under light. In hypoxic seawater without light, the concentrations of RNA but not DNA markers correlated with that of E. coli. Generally, the correlations between Enterococcus spp. and Bacteroidales were insignificant. These results suggest that either DNA or RNA markers may complement E. coli in the tiered approach for normoxic or hypoxic seawater under light. When light is absent, either DNA or RNA markers may serve for normoxic seawater, but only the RNA markers are suitable for hypoxic seawater.

  4. Development of pre-concentration procedure for the determination of Hg isotope ratios in seawater samples.

    Science.gov (United States)

    Štrok, Marko; Hintelmann, Holger; Dimock, Brian

    2014-12-03

    Hg concentrations in seawater are usually too low to allow direct (without pre-concentration and removal of salt matrix) measurement of its isotope ratios with multicollector-inductively coupled plasma mass spectrometry (MC-ICP-MS). Therefore, a new method for the pre-concentration of Hg from large volumes of seawater was developed. The final method allows for relatively fast (about 2.5Lh(-1)) and quantitative pre-concentration of Hg from seawater samples with an average Hg recovery of 98±6%. Using this newly developed method we determined Hg isotope ratios in seawater. Reference seawater samples were compared to samples potentially impacted by anthropogenic activity. The results show negative mass dependent fractionation relative to the NIST 3133 Hg standard with δ(202)Hg values in the range from -0.50‰ to -1.50‰. In addition, positive mass independent fractionation of (200)Hg was observed for samples from reference sites, while impacted sites did not show significant Δ(200)Hg values. Although the influence of the impacted sediments is limited to the seawater and particulate matter in very close proximity to the sediment, this observation may raise the possibility of using Δ(200)Hg to distinguish between samples from impacted and reference sites. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Substrate Use of Pseudovibrio sp. Growing in Ultra-Oligotrophic Seawater

    Science.gov (United States)

    Schwedt, Anne; Seidel, Michael; Dittmar, Thorsten; Simon, Meinhard; Bondarev, Vladimir; Romano, Stefano; Lavik, Gaute; Schulz-Vogt, Heide N.

    2015-01-01

    Marine planktonic bacteria often live in habitats with extremely low concentrations of dissolved organic matter (DOM). To study the use of trace amounts of DOM by the facultatively oligotrophic Pseudovibrio sp. FO-BEG1, we investigated the composition of artificial and natural seawater before and after growth. We determined the concentrations of dissolved organic carbon (DOC), total dissolved nitrogen (TDN), free and hydrolysable amino acids, and the molecular composition of DOM by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR-MS). The DOC concentration of the artificial seawater we used for cultivation was 4.4 μmol C L-1, which was eight times lower compared to the natural oligotrophic seawater we used for parallel experiments (36 μmol C L -1). During the three-week duration of the experiment, cell numbers increased from 40 cells mL-1 to 2x104 cells mL -1 in artificial and to 3x105 cells mL -1 in natural seawater. No nitrogen fixation and minor CO2 fixation (seawater, using unexpected organic compounds to fuel their energy, carbon and nitrogen requirements. PMID:25826215

  6. Geochemical processes at a fresh/seawater interface in a shallow sandy aquifer

    DEFF Research Database (Denmark)

    Andersen, Martin Søgaard; Iversen, Vibeke Margrethe Nyvang; Postma, Diederik Jan

    2001-01-01

    Chemical processes in a natural fresh-/seawater mixing zone were studied in a shallow sandy aquifer. The dominant redox-processes are sulfate reduction and methanogenesis. Methanogenesis produces CO2, which causes calcite dissolution. The produced calcium induces ion exchange with sodium. The fin...... result of these interactions between different types of geochemical processes is an anoxic groundwater enriched in bicarbonate and sodium.......Chemical processes in a natural fresh-/seawater mixing zone were studied in a shallow sandy aquifer. The dominant redox-processes are sulfate reduction and methanogenesis. Methanogenesis produces CO2, which causes calcite dissolution. The produced calcium induces ion exchange with sodium. The final...

  7. Influences of air pollutants on polymeric materials. Natural weathering of polymers

    Energy Technology Data Exchange (ETDEWEB)

    Reichert, T.F.R. [Fraunhofer-Institut fuer Chemische Technologie, Pfinztal-Berghausen (Germany)

    1995-12-31

    Polymeric materials are affected during their entire service life by a number of environmental influences. These originate from both man made and natural sources. Such environmental influences include solar radiation, temperature, humidity and air pollutant effects. They all act together, some independently and some synergistically, to influence material properties, as well as functionality, service life, quality and reliability of the poly materials and systems. The main degradation process is chain scission with loss of molecular weight and oxidation, followed by fading of colours and loss of gloss and mechanical strength. Due to the large number of different types of polymers there are many types of degradation processes and it is difficult to generalise about the effects of the environment on organic materials. Materials, as opposed to organisms, have no self-repair mechanism which allows them to tolerate a certain level of stress. In principle, therefore, it is not possible to define critical levels for the effects of pollutants on materials below which no deterioration occurs. Material deterioration by weathering is normally a very slow process lasting some or more years. Therefore attempts have been made to produce deterioration in short-term experiments by using high stress levels. The limits for the high stress levels are given by the comparability of the obtained damage from artificially accelerated weathering with these from real natural weathering. To investigate the damage caused by air pollutants on polymeric materials, samples were natural weathered with some light exposed and some dark stored samples in different climatic and polluted areas of Germany. The weathering stations are closed to the continuously measuring stations for air quality

  8. Influences of air pollutants on polymeric materials. Natural weathering of polymers

    Energy Technology Data Exchange (ETDEWEB)

    Reichert, T F.R. [Fraunhofer-Institut fuer Chemische Technologie, Pfinztal-Berghausen (Germany)

    1996-12-31

    Polymeric materials are affected during their entire service life by a number of environmental influences. These originate from both man made and natural sources. Such environmental influences include solar radiation, temperature, humidity and air pollutant effects. They all act together, some independently and some synergistically, to influence material properties, as well as functionality, service life, quality and reliability of the poly materials and systems. The main degradation process is chain scission with loss of molecular weight and oxidation, followed by fading of colours and loss of gloss and mechanical strength. Due to the large number of different types of polymers there are many types of degradation processes and it is difficult to generalise about the effects of the environment on organic materials. Materials, as opposed to organisms, have no self-repair mechanism which allows them to tolerate a certain level of stress. In principle, therefore, it is not possible to define critical levels for the effects of pollutants on materials below which no deterioration occurs. Material deterioration by weathering is normally a very slow process lasting some or more years. Therefore attempts have been made to produce deterioration in short-term experiments by using high stress levels. The limits for the high stress levels are given by the comparability of the obtained damage from artificially accelerated weathering with these from real natural weathering. To investigate the damage caused by air pollutants on polymeric materials, samples were natural weathered with some light exposed and some dark stored samples in different climatic and polluted areas of Germany. The weathering stations are closed to the continuously measuring stations for air quality

  9. Influence of the oxyanion nature of the electrolyte on the corrosion/passivation behaviour of nickel

    International Nuclear Information System (INIS)

    Trompette, J.L.; Massot, L.; Vergnes, H.

    2013-01-01

    Highlights: •Influence of oxyanion nature on the passivation of nickel. •Constitutive atoms of oxyanion incorporated into the passive film. •Evidence of direct bonding between N and Ni surface. -- Abstract: The electrochemical behaviour of nickel in the presence of various electrolyte solutions at 0.1 mol/L concentration exhibits a distinction according to the oxyanion nature of the investigated anions. Passivity is achieved with oxyanions whereas it fails with anions not containing oxygen. SIMS and XPS measurements performed from isotopic and non isotopic KNO 3 electrolytes indicate that the oxygen and nitrogen atoms from nitrate oxyanions are incorporated into the passive film during anodic polarization and with evidence of a direct bonding between nitrogen and nickel surface

  10. Exploring the Influence of Nature Relatedness and Perceived Science Knowledge on Proenvironmental Behavior

    Directory of Open Access Journals (Sweden)

    Amanda Obery

    2017-01-01

    Full Text Available This study was undertaken to investigate the factors influencing proenvironmental behavior of individuals residing in the Northern Rocky Mountains (N = 267. Measures of relatedness to nature and perceived science knowledge were collected through a convenience sample approach using multiple avenues such as city email lists, organizational newsletters, and social media channels. Analysis of the data was conducted using both partial least squares and covariance based structural equation modeling to explore the relationships between the constructs. Additionally, qualitative definitions of proenvironmental behavior were investigated in order to address potential gaps between self-reported and observed behaviors. Quantitative findings show a renewed positive connection between science education, nature relatedness, and proenvironmental behaviors. Furthermore, qualitative findings suggest positive relationships between how publicly people are willing to share their passion for the outdoors and their willingness to engage in proenvironmental behaviors.

  11. The influence of gamma irradiation on natural dyeing properties of cotton and flax fabrics

    Science.gov (United States)

    Chirila, Laura; Popescu, Alina; Cutrubinis, Mihalis; Stanculescu, Ioana; Moise, Valentin Ioan

    2018-04-01

    Fabrics made of 100% cotton and 100% flax respectively were exposed at ambient temperature to gamma radiation doses, from 5 to 40 kGy, using a Co-60 research irradiator. After the irradiation treatment the fabrics were subjected to dyeing process with Itodye Nat Pomegranate commercial natural dye. The influence of gamma irradiation treatment on the physical-mechanical properties, dyeing and surface morphology of natural fibres were investigated. Gamma ray treatment of 40 kGy was the most effective in the case of fabrics made from 100% cotton, enhancing the colour strength as evidenced by K/S value. The results obtained from the mechanical properties of fabrics made of 100% flax indicated that the dose of 40 kGy leads to a decrease of tensile strength up of to 41.5%. Infrared spectroscopy was used to monitor chemical and structural changes in cellulosic fibres induced during processing. Crystallinity indices calculated from various bands ratio showed insignificant variations for cotton and small variations in the case of flax. The surface morphology of irradiated cotton fabrics did not show significant changes even at the highest dose of 40 kGy, while the low doses applied on flax fabrics led to an appearance of small changes of surface morphology. The gamma irradiation increased the uptake of natural dyes on natural cellulosic fibres.

  12. Influence of forest management systems on natural resource use and provision of ecosystem services in Tanzania.

    Science.gov (United States)

    Strauch, Ayron M; Rurai, Masegeri T; Almedom, Astier M

    2016-09-15

    Social, religious and economic facets of rural livelihoods in Sub-Saharan Africa are heavily dependent on natural resources, but improper resource management, drought, and social instability frequently lead to their unsustainable exploitation. In rural Tanzania, natural resources are often governed locally by informal systems of traditional resource management (TRM), defined as cultural practices developed within the context of social and religious institutions over hundreds of years. However, following independence from colonial rule, centralized governments began to exercise jurisdictional control over natural resources. Following decades of mismanagement that resulted in lost ecosystem services, communities demanded change. To improve resource protection and participation in management among stakeholders, the Tanzanian government began to decentralize management programs in the early 2000s. We investigated these two differing management approaches (traditional and decentralized government) in Sonjo communities, to examine local perceptions of resource governance, management influences on forest use, and their consequences for forest and water resources. While 97% of households understood the regulations governing traditionally-managed forests, this was true for only 39% of households for government-managed forests, leading to differences in forest use. Traditional management practices resulted in improved forest condition and surface water quality. This research provides an essential case study demonstrating the importance of TRM in shaping decision frameworks for natural resource planning and management. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. The influence of shale gas mining activities on the natural environment in Poland

    Science.gov (United States)

    Pyssa, Justyna

    2017-10-01

    In the paper the main threats to the environment arising from works related to the exploration of gas from unconventional sources have been discussed. The influence of exploration works on the atmosphere (the emission of gases to the atmosphere as a result of fuel combustion, the emission of noise by drilling equipment) has been explained. Threats to the hydrological balance associated with the intake of water for performing the process of fracturing have been discussed. Legal regulations connected with waste management, water resource management and protected areas (Nature 2000) have been presented.

  14. The influence of radiolytic sensitizers in natural rubber latex vulcanization induced by ionizing radiation

    International Nuclear Information System (INIS)

    Guedes, S.M.L.; Souza, A. de

    1991-01-01

    This work made on radiation vulcanization of natural rubber latex process by gamma rays from 60 Co source and electron beam of 1.5 MeV, 25 m A by Dynamitron, instead of classic process using sulfur. The experiment was carried out to study the influence of sensitizers (C Cl 4 and n-butyl acrylate) and was reported the vulcanization dose for each sensitizers, related to maximum tensile strength. The results show the possibility to introduce the volatile sensitizer (n-butyl acrylate) instead of C Cl 4 (toxic) in industry applications. (author)

  15. Temporal variability of fish larvae assemblages: influence of natural and anthropogenic disturbances

    Directory of Open Access Journals (Sweden)

    David A. Reynalte-Tataje

    Full Text Available Natural and induced disturbances greatly influence the temporal distribution of ichthyoplankton abundance. This study assesses and compares the temporal variability of fish larvae assemblages in controlled and free environments to determine the influence of environment variables on the main taxa in these systems. The study was conducted at the Chapecó (without dam impact and Ligeiro (with dam impact river mouths, which are located in the upper Uruguay River. Samples were made between October 2001 and March 2004 during three reproductive periods. The larvae assemblages were composed of small and medium-sized Characiformes and Siluriformes. The variation in the distribution of larvae was mainly temporal (>85%. When the three reproductive periods were compared, it was observed in the second period, characterized by a larger water flow and a lower temperature, that there was a reduction in abundance, a lower number of taxa, an absence of stages in post-flexion and a high dissimilarity in larvae assemblage structure. In general, the environmental variables of water flow and temperature most influenced the distribution of egg and larvae abundance. In the studied area, a smaller temporal variability was observed in the structure of larvae assemblages at the sampling sites in the Chapecó River mouth than in in the Ligeiro River mouth under the influence of dams.

  16. Recovery of uranium from seawater using amidoxime hollow fibers

    International Nuclear Information System (INIS)

    Saito, K.; Uezu, K.; Hori, T.; Furusaki, S.; Sugo, T.; Okamoto, J.

    1988-01-01

    A novel amidoxime-group-containing adsorbent of hollow-fiber form (AO-H fiber) was prepared by radiation-induced graft polymerization of acrylonitrile onto a polyethylene hollow fiber, followed by chemical conversion of the produced cyano group to an amidoxime group. Distribution of the amidoxime group was uniform throughout hollow-fiber membrane. The fixed-bed adsorption column, 30 cm in length and charged with the bundle of AO-H fibers, was found to adsorb uranium from natural seawater at a sufficiently high rate: 0.66 mg uranium per g of adsorbent in 25 days

  17. Development of sorbers for the recovery of uranium from seawater. Part 2. The accumulation of uranium from seawater by resins containing amidoxime and imidoxime functional groups

    International Nuclear Information System (INIS)

    Astheimer, L.; Schenk, H.J.; Witte, E.G.; Schwochau, K.

    1983-01-01

    Hydroxylamine derivatives of cross-linked poly(acrylonitriles), so-called poly(acrylamidoxime) resins, are suitable for the accumulation of uranium from natural seawater of pH = 8.1 to 8.3. Depending on the method of manufacture, these sorbers yield excellent uranium loadings up to some thousand ppM which roughly equals the average uranium content of actually explored uranium ores. The rate of uranium uptake, which is 5 to 30 ppM/d at room temperature, increases with increasing temperature of seawater. Uranium can be eluted by 1 M HCl with an elution efficiency of more than 90%. Owing to a certain instability of the uranium binding groups in acid eluants, the uranium uptake decreases with increasing number of sorption-elution cycles. Hydroxylamine derivatives of poly(acrylonitrile) are shown to contain simultaneously at least two kinds of functional groups: open-chain amidoxime groups which are stable and cyclic imidoxime groups which are unstable in 1 M HCl. Experimental evidence is presented that the uptake of uranium from natural seawater is closely related to the presence of cyclic imidoxime configurations in the polyacrylic lattice. Polystyrene and poly(glycidylmethacrylate)-based amidoxime and imide dioxime resins are less effective in extracting uranium from natural seawater. 10 figures, 4 tables

  18. Variable response of three Trifolium repens ecotypes to soil flooding by seawater.

    Science.gov (United States)

    White, Anissia C; Colmer, Timothy D; Cawthray, Greg R; Hanley, Mick E

    2014-08-01

    Despite concerns about the impact of rising sea levels and storm surge events on coastal ecosystems, there is remarkably little information on the response of terrestrial coastal plant species to seawater inundation. The aim of this study was to elucidate responses of a glycophyte (white clover, Trifolium repens) to short-duration soil flooding by seawater and recovery following leaching of salts. Using plants cultivated from parent ecotypes collected from a natural soil salinity gradient, the impact of short-duration seawater soil flooding (8 or 24 h) on short-term changes in leaf salt ion and organic solute concentrations was examined, together with longer term impacts on plant growth (stolon elongation) and flowering. There was substantial Cl(-) and Na(+) accumulation in leaves, especially for plants subjected to 24 h soil flooding with seawater, but no consistent variation linked to parent plant provenance. Proline and sucrose concentrations also increased in plants following seawater flooding of the soil. Plant growth and flowering were reduced by longer soil immersion times (seawater flooding followed by drainage and freshwater inputs), but plants originating from more saline soil responded less negatively than those from lower salinity soil. The accumulation of proline and sucrose indicates a potential for solute accumulation as a response to the osmotic imbalance caused by salt ions, while variation in growth and flowering responses between ecotypes points to a natural adaptive capacity for tolerance of short-duration seawater soil flooding in T. repens. Consequently, it is suggested that selection for tolerant ecotypes is possible should the predicted increase in frequency of storm surge flooding events occur. © The Author 2014. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  19. Influence of heat treatment on physicochemical and rheological characteristics of natural yogurts

    Directory of Open Access Journals (Sweden)

    Juliana Aparecida Célia

    2017-08-01

    Full Text Available The aim of this study was to assess the influence of heat treatment on physicochemical and rheological characteristics of natural yogurts, as well as the influence of lyophilization process on natural yogurts after reconstitution. In the first experiment, three yogurt treatments were processed, as follows: Treatment 1, yogurt produced with raw refrigerated milk; Treatment 2, yogurt produced with refrigerated pasteurized milk; and Treatment 3, yogurt produced with UHT (ultra-high temperature milk, in addition to analyses of fat, protein, moisture, titratable acidity, and pH. The shelf life of yogurts at 1, 8, 15, 22, and 29 days of storage, as well as pH, acidity, syneresis, viscosity, viable lactic bacteria, and total coliforms were also assessed. In the second experiment, yogurts were submitted to lyophilization process, performed by scanning electron microscopy analysis and subsequently in those reconstituted, in addition to being assessed the physicochemical, rheological, and viable lactic bacteria characteristics. The results found in the first experiment showed that heat treatment was positive for viscosity, syneresis, and lactic bacteria, being viable until the 15th day of storage only for yogurts submitted to heat treatment. In the second experiment, lyophilization preserved the physicochemical characteristics of yogurts, but the number of initial lactic bacteria was different, also negatively affecting yogurt viscosity.

  20. Dissolution of basaltic glass in seawater: Mechanism and rate

    International Nuclear Information System (INIS)

    Crovisier, J.L.; Honnorez, J.; Eberhart, J.P.

    1987-01-01

    Basaltic glasses are considered as natural analogues for nuclear waste glasses. Thermodynamic computer codes used to evaluate long term behavior of both nuclear waste and basaltic glasses require the knowledge of the dissolution mechanism of the glass network. The paper presents the results of a series of experiments designed to study the structure and chemical composition of alteration layers formed on the surface of artificial tholeiitic glass altered in artificial seawater. Experiments were performed at 60 degree C, 1 bar and 350 bars in non-renewed conditions. A natural sample from Palagonia (Sicily) has been studied by electron microscopy and comparison between natural and experimental palagonitic layers is made. The behavior of dissolved silica during experiments, and both the structure and the chemical composition of the palagonitic layers, indicate that they form by precipitation of secondary minerals from solution after a total breakdown of the glassy network, i.e., congruent dissolution of the glass. Hence the dissolution equation necessary for thermodynamic modelling of basaltic glass dissolution in seawater at low temperature must be written as a simple stoichiometric process. These experiments indicate that the transformation of glass to palagonitic material is not isovolumetric. Hence it is preferable to use Fe or Ti as conservative elements for chemical budget calculations

  1. Development of an Assessment Procedure for Seawater Intrusion Mitigation

    Science.gov (United States)

    Hsi Ting, F.; Yih Chi, T.

    2017-12-01

    The Pingtung Plain is one of the areas with extremely plentiful groundwater resources in Taiwan. Due to that the application of the water resource is restricted by significant variation of precipitation between wet and dry seasons, groundwater must be used as a recharge source to implement the insufficient surface water resource during dry seasons. In recent years, the coastal aquaculture rises, and the over withdrawn of groundwater by private well results in fast drop of groundwater level. Then it causes imbalance of groundwater supply and leads to serious seawater intrusion in the coastal areas. The purpose of this study is to develop an integrated numerical model of groundwater resources and seawater intrusion. Soil and Water Assessment Tool (SWAT), MODFLOW and MT3D models were applied to analyze the variation of the groundwater levels and salinity concentration to investigate the correlation of parameters, which are used to the model applications in order to disposal saltwater intrusion. The data of groundwater levels, pumping capacity and hydrogeological data to were collected to build an integrated numerical model. Firstly, we will collect the information of layered aquifer and the data of hydrological parameters to build the groundwater numerical model at Pingtung Plain, and identify the amount of the groundwater which flow into the sea. In order to deal with the future climate change conditions or extreme weather conditions, we will consider the recharge with groundwater model to improve the seawater intrusion problem. The integrated numerical model which describes that seawater intrusion to deep confined aquifers and shallow unsaturated aquifers. Secondly, we will use the above model to investigate the weights influenced by different factors to the amount area of seawater intrusion, and predict the salinity concentration distribution of evaluation at coastal area of Pingtung Plain. Finally, we will simulate groundwater recharge/ injection at the coastal

  2. Microbial Degradation Behavior in Seawater of Polyester Blends Containing Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate (PHBHHx

    Directory of Open Access Journals (Sweden)

    Hitoshi Sashiwa

    2018-01-01

    Full Text Available The microbial degradation behavior of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate (PHBHHx and its compound with several polyesters such as poly(butylene adipate-co-telephtharate (PBAT, poly(butylene succinate (PBS, and polylactic acid (PLA in seawater was tested by a biological oxygen demand (BOD method. PHBHHx showed excellent biodegradation in seawater in this study. In addition, the biodegradation rate of several blends was much influenced by the weight ratio of PHBHHx in their blends and decreased in accordance with the decrement of PHBHHX ratio. The surface morphology of the sheet was important factor for controlling the biodegradation rate of PHBHHx-containing blends in seawater.

  3. [The effect of hypertonic seawater and isotonic seawater for nasal mucosa of allergic rhinitis mice model].

    Science.gov (United States)

    Deng, Zhifeng; Xu, Yu; Ou, Jin; Xiang, Rong; Tao, Zezhang

    2014-12-01

    To study the effect of hypertonic seawater and isotonic seawater for nasal mucosa of allergic rhinitis mice model, and explore the possible mechanism of nasal irrigation with seawater in treatment of allergic rhinitis. We used Der pl to make allergic rhinitis model of BALB/c mice, and divided them into three groups randomly. Nasal irrigation with hypertonic seawater (HS) or isotonic seawater (IS) in the treatment group 1-14 days after modeling, and black control (BC) group was given no treatment after modeling. Normal control (NC) group was given no treatment, the number of rubs and sneezings in each group were counted in 30 min after the last nasal irrigation. Mice were then killed 24 h after the last therapy. The noses of mice from each group were removed and fixed, then the slices were stained with hematoxylin and eosin, the others were observed by transmission electron microscope. Mice with hypertonic seawater and isotonic seawater were significantly improved in rubs and sneezings compared to the black control group (P 0. 05); Ciliated columnar epithelium cells in mucosal tissues of HS group and IS group were arranged trimly, better than that in the black control group. Morphology and microstructure in nasal mucosal of HS group was closer to the normal group than in IS group. The injury of nasal mucosa ciliated epithelium was significantly improved by nasal irrigation with hypertonic seawater and isotonic seawater, and the former is better than the latter, the mechanism of nasal irrigation with seawater in treatment of allergic rhinitis may rely on repairing the injured nasal mucosa ciliated epithelium, thereby the symptoms of nasal was reduced.

  4. Initial steps in the microbially influenced corrosion (MIC) of metallic surfaces in a natural marine environment

    International Nuclear Information System (INIS)

    Esteso, M.A.; Estrella, C.N.; Dolores de la Rosa, M.; Martinez-Trujillo, R.; Rosales, B.M.; Podesta, J.J.

    1992-01-01

    Immersion of various metal samples in polluted seawater from Tenerife Harbor was followed by microbial attachment as an intermediate step in fouling development. The purpose of this research was to determine the initial steps in MIC by identifying the different microbial species attached to the respective metal or alloy. Image analysis was used to determine the morphologic changes in the metal surfaces. The corrosion products were determined by X-ray diffraction. The open circuit potentials were measured periodically and their variation with time used to assess the electrochemical behavior in the aforementioned marine environment

  5. The Lagoon of Venice : the result of both natural factors and human influence

    Directory of Open Access Journals (Sweden)

    Oscar RAVERA

    2000-02-01

    Full Text Available This paper aims to present a picture of the lagoon of Venice and analyze the combined effects of natural factors and human influence on this fragile ecotone. The structure, functioning and evolution of the lagoon are illustrated. Under natural conditions, the solid load from the tributaries would transform the lagoon into dry land or, if the violence of the sea exceeded the solid load from the watershed, the lagoon would evolve into a marine bay. This natural succession has been hindered by the works undertaken by the Republic of Venice uninterruptedly through the centuries, because the lagoon environment was essential to the life and power of Venice. The effects of human activities from the beginning of the Venetian Republic to the present are described. In addition, the influence of socio-economic development on the lagoon area and, particularly, the impact of intensive agriculture and industrialization are discussed. A possible effect of eutrophication was the dramatic proliferation of the opportunistic macroalga Ulva rigida, which for about a decade played an important role in the physical, chemical and biological characteristics of the lagoon. At present, the most crucial problems of Venice and its lagoon are: the lowering of the level of the city in relation to that of the sea, the continuous decline in the number of inhabitants, the increasing frequency of the “high water” phenomenon, air and water pollution, and the increased erosion and salinity of the lagoon. The recent measures taken and those still to be applied for conserving and recovering Venice and its lagoon and, particularly, the works for preventing the risk of high water are compared. There is an evident need for a new type of socio-economic development in symbiosis with the environment and tradition of Venice.

  6. Natural variation in sensory-motor white matter organization influences manifestations of Huntington's disease.

    Science.gov (United States)

    Orth, Michael; Gregory, Sarah; Scahill, Rachael I; Mayer, Isabella Sm; Minkova, Lora; Klöppel, Stefan; Seunarine, Kiran K; Boyd, Lara; Borowsky, Beth; Reilmann, Ralf; Bernhard Landwehrmeyer, G; Leavitt, Blair R; Roos, Raymund Ac; Durr, Alexandra; Rees, Geraint; Rothwell, John C; Langbehn, Douglas; Tabrizi, Sarah J

    2016-12-01

    While the HTT CAG-repeat expansion mutation causing Huntington's disease (HD) is highly correlated with the rate of pathogenesis leading to disease onset, considerable variance in age-at-onset remains unexplained. Therefore, other factors must influence the pathogenic process. We asked whether these factors were related to natural biological variation in the sensory-motor system. In 243 participants (96 premanifest and 35 manifest HD; 112 controls), sensory-motor structural MRI, tractography, resting-state fMRI, electrophysiology (including SEP amplitudes), motor score ratings, and grip force as sensory-motor performance were measured. Following individual modality analyses, we used principal component analysis (PCA) to identify patterns associated with sensory-motor performance, and manifest versus premanifest HD discrimination. We did not detect longitudinal differences over 12 months. PCA showed a pattern of loss of caudate, grey and white matter volume, cortical thickness in premotor and sensory cortex, and disturbed diffusivity in sensory-motor white matter tracts that was connected to CAG repeat length. Two further major principal components appeared in controls and HD individuals indicating that they represent natural biological variation unconnected to the HD mutation. One of these components did not influence HD while the other non-CAG-driven component of axial versus radial diffusivity contrast in white matter tracts were associated with sensory-motor performance and manifest HD. The first component reflects the expected CAG expansion effects on HD pathogenesis. One non-CAG-driven component reveals an independent influence on pathogenesis of biological variation in white matter tracts and merits further investigation to delineate the underlying mechanism and the potential it offers for disease modification. Hum Brain Mapp 37:4615-4628, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  7. Influence of natural mobile organic matter on europium retention on Bure clay rock

    International Nuclear Information System (INIS)

    Vu-Do, Laurence

    2013-01-01

    Bure clay rock (CR) was chosen as host rock for the French high and intermediate level long lived radioactive waste repository. This choice is mostly explained by the retention ability of the Callovo-Oxfordian rock (COx). Bure clay rock contains natural organic matter (OM) that could have an influence on radionuclide retention. The aim of this work is to assess the influence of natural mobile OM on the retention of Eu on clay rock. Eu was chosen as a chemical model for trivalent actinides contained in vitrified waste. Three organic molecules were studied: suberic, sorbic and tiglic acids, small organic acids identified in COx pore water. All the experiments were carried out in an environment recreating COx water (pH=7.5; I=0.1 mol/L; PCO 2 =10 -2 bar).Clay rock sample characterization showed that the sample used in this work was similar to those previously extracted from the area of interest and that it was necessary to maintain pH at 7.5 to avoid altering the clay rock. The Eu-OM system study indicated that organic acids had no influence on Eu speciation in COx water. The Eu-CR system experimental study confirmed that retention implied sorption on CR (C(Eu)≤6.10 -6 mol/L) and precipitation in COx water (C(Eu)≥6.10 -6 mol/L). Distribution coefficient Rd (quantifying sorption) was estimated at 170 ± 30 L/g. This high value is consistent with literature values obtained on clay rocks. The ternary Eu-OM-CR system study showed a slight increase of sorption in the presence of organic matter. This synergistic effect is very satisfactory in terms of storage security: the presence of small organic acids in clay rock does not question retention properties with respect to europium and trivalent actinides. (author)

  8. Influence of some packaging materials and of natural tocopherols on the sensory properties of breakfast cereals.

    Science.gov (United States)

    Paradiso, Vito M; Caponio, Francesco; Summo, Carmine; Gomes, Tommaso

    2014-04-01

    The combined effect of natural antioxidants and packaging materials on the quality decay of breakfast cereals during storage was evaluated. Corn flakes were produced on industrial scale, using different packages and adding natural tocopherols to the ingredients, and stored for 1 year. The samples were then submitted to sensory analysis and HS-solid phase microextraction/gas chromatography/mass spectrometry (SPME/GC/MS) analysis. The packaging had a significant influence on the sensory profile of the aged product: metallized polypropylene gave the highest levels of oxidation compounds and sensory defects. The sensory profile was improved using polypropylene and especially high-density polyethylene. Natural tocopherols reduced the sensory decay of the flakes and the oxidative evolution of the volatile profile. They gave the most remarkable improvement in polypropylene (either metallized or not) packs. Polypropylene showed a barrier effect on the scalping of volatiles outside of the pack. This led to higher levels of oxidation volatiles and faster rates of the further oxidative processes involving the volatiles.

  9. Human and natural influences on the changing thermal structure of the atmosphere.

    Science.gov (United States)

    Santer, Benjamin D; Painter, Jeffrey F; Bonfils, Céline; Mears, Carl A; Solomon, Susan; Wigley, Tom M L; Gleckler, Peter J; Schmidt, Gavin A; Doutriaux, Charles; Gillett, Nathan P; Taylor, Karl E; Thorne, Peter W; Wentz, Frank J

    2013-10-22

    Since the late 1970s, satellite-based instruments have monitored global changes in atmospheric temperature. These measurements reveal multidecadal tropospheric warming and stratospheric cooling, punctuated by short-term volcanic signals of reverse sign. Similar long- and short-term temperature signals occur in model simulations driven by human-caused changes in atmospheric composition and natural variations in volcanic aerosols. Most previous comparisons of modeled and observed atmospheric temperature changes have used results from individual models and individual observational records. In contrast, we rely on a large multimodel archive and multiple observational datasets. We show that a human-caused latitude/altitude pattern of atmospheric temperature change can be identified with high statistical confidence in satellite data. Results are robust to current uncertainties in models and observations. Virtually all previous research in this area has attempted to discriminate an anthropogenic signal from internal variability. Here, we present evidence that a human-caused signal can also be identified relative to the larger "total" natural variability arising from sources internal to the climate system, solar irradiance changes, and volcanic forcing. Consistent signal identification occurs because both internal and total natural variability (as simulated by state-of-the-art models) cannot produce sustained global-scale tropospheric warming and stratospheric cooling. Our results provide clear evidence for a discernible human influence on the thermal structure of the atmosphere.

  10. Action adaptation during natural unfolding social scenes influences action recognition and inferences made about actor beliefs.

    Science.gov (United States)

    Keefe, Bruce D; Wincenciak, Joanna; Jellema, Tjeerd; Ward, James W; Barraclough, Nick E

    2016-07-01

    When observing another individual's actions, we can both recognize their actions and infer their beliefs concerning the physical and social environment. The extent to which visual adaptation influences action recognition and conceptually later stages of processing involved in deriving the belief state of the actor remains unknown. To explore this we used virtual reality (life-size photorealistic actors presented in stereoscopic three dimensions) to see how visual adaptation influences the perception of individuals in naturally unfolding social scenes at increasingly higher levels of action understanding. We presented scenes in which one actor picked up boxes (of varying number and weight), after which a second actor picked up a single box. Adaptation to the first actor's behavior systematically changed perception of the second actor. Aftereffects increased with the duration of the first actor's behavior, declined exponentially over time, and were independent of view direction. Inferences about the second actor's expectation of box weight were also distorted by adaptation to the first actor. Distortions in action recognition and actor expectations did not, however, extend across different actions, indicating that adaptation is not acting at an action-independent abstract level but rather at an action-dependent level. We conclude that although adaptation influences more complex inferences about belief states of individuals, this is likely to be a result of adaptation at an earlier action recognition stage rather than adaptation operating at a higher, more abstract level in mentalizing or simulation systems.

  11. Connecting Students to Nature--How Intensity of Nature Experience and Student Age Influence the Success of Outdoor Education Programs

    Science.gov (United States)

    Braun, Tina; Dierkes, Paul

    2017-01-01

    Nature connectedness counts as a crucial predictor of pro-environmental behavior. For counteracting today's environmental issues a successful re-connection of individuals to nature is necessary. Besides the promotion of knowledge transfer the aim of the educational program presented in this study is to connect students to their environment. This…

  12. Seawater-Soluble Pigments and Their Potential Use in Self-Polishing Antifouling Paints: Simulation-based Screening Tool

    DEFF Research Database (Denmark)

    Kiil, Søren; Dam-Johansen, Kim; Erik Weinell, Claus

    2002-01-01

    This work concerns the on-going development of efficient and environmentally friendly antifouling paints for biofouling control on large ocean-going ships. It is illustrated how a detailed mathematical model for a self-polishing antifouling paint exposed to seawater can be used as a product...... solubility and seawater diffusivity of dissolved pigment species have a significant influence on the polishing and leaching behaviour of a typical self-polishing paint system. The pigment size distribution, on the other hand, only has a minor influence on the paint-seawater interaction. Simulations also...... indicate that only compounds which are effective against biofouling at very low seawater concentrations are useful as active antifouling paint ingredients. The need for model verification and exploration of practical issues, subsequent a given pigment has been found of interest, is discussed. The model...

  13. Sea-level rise impacts on seawater intrusion in coastal aquifers: Review and integration

    Science.gov (United States)

    Ketabchi, Hamed; Mahmoodzadeh, Davood; Ataie-Ashtiani, Behzad; Simmons, Craig T.

    2016-04-01

    Sea-level rise (SLR) influences groundwater hydraulics and in particular seawater intrusion (SWI) in many coastal aquifers. The quantification of the combined and relative impacts of influential factors on SWI has not previously been considered in coastal aquifers. In the present study, a systematic review of the available literature on this topic is first provided. Then, the potential remaining challenges are scrutinized. Open questions on the effects of more realistic complexities such as gradual SLR, parameter uncertainties, and the associated influences in decision-making models are issues requiring further investigation. We assess and quantify the seawater toe location under the impacts of SLR in combination with recharge rate variations, land-surface inundation (LSI) due to SLR, aquifer bed slope variation, and changing landward boundary conditions (LWBCs). This is the first study to include all of these factors in a single analysis framework. Both analytical and numerical models are used for these sensitivity assessments. It is demonstrated that (1) LSI caused by SLR has a significant incremental impact on the seawater toe location, especially in the flatter coasts and the flux-controlled (FC) LWBCs, however this impact is less than the reported orders of magnitude differences which were estimated using only analytical solutions; (2) LWBCs significantly influence the SLR impacts under almost all conditions considered in this study; (3) The main controlling factors of seawater toe location are the magnitudes of fresh groundwater discharge to sea and recharge rate. Regional freshwater flux entering from the landward boundary and the groundwater hydraulic gradient are the major contributors of fresh groundwater discharge to sea for both FC and head-controlled (HC) systems, respectively; (4) A larger response of the aquifer and larger seawater toe location changes are demonstrable for a larger ratio of the aquifer thickness to the aquifer length particularly in

  14. Extracting Minerals from Seawater: An Energy Analysis

    Directory of Open Access Journals (Sweden)

    Ugo Bardi

    2010-04-01

    Full Text Available The concept of recovering minerals from seawater has been proposed as a way of counteracting the gradual depletion of conventional mineral ores. Seawater contains large amounts of dissolved ions and the four most concentrated metal ones (Na, Mg, Ca, K are being commercially extracted today. However, all the other metal ions exist at much lower concentrations. This paper reports an estimate of the feasibility of the extraction of these metal ions on the basis of the energy needed. In most cases, the result is that extraction in amounts comparable to the present production from land mines would be impossible because of the very large amount of energy needed. This conclusion holds also for uranium as fuel for the present generation of nuclear fission plants. Nevertheless, in a few cases, mainly lithium, extraction from seawater could provide amounts of metals sufficient for closing the cycle of metal use in the economy, provided that an increased level of recycling can be attained.

  15. Pasteurization: A reliable method for preservation of nutrient in seawater samples for inter-laboratory and field applications

    OpenAIRE

    Daniel, Anne; Kerouel, Roger; Aminot, Alain

    2012-01-01

    Following previous work, the production of reference material for nutrients in seawater, using pasteurization as a preservation method, was carried out seven times between 2006 and 2010 in the framework of inter-laboratory exercises. The preparation of samples from natural seawater allowed to become depleted in nutrients then spiked, bottled and pasteurized, is described. Five main nutrients are involved in this study: ammonium, nitrite, nitrate, phosphate and silicate. Bottles are in glass f...

  16. Influence of Student Beliefs about Nature of School Mathematics on Their Achievement at Secondary Level in Kerala

    Science.gov (United States)

    Gafoor, Kunnathodi Abdul; Sarabi, M. K.

    2016-01-01

    This study probes students' beliefs about nature of mathematics, difficulty in learning mathematics sourcing from these and their influence on achievement in mathematics. Questionnaire survey on 458, 9th standard students randomly selected from schools of Malappuram district elicited data on nature of school mathematics and difficulty arising out…

  17. Influence of forest and rangeland management on anadromous fish habitat in Western North America: impacts of natural events.

    Science.gov (United States)

    Douglas N. Swanston

    1980-01-01

    Natural events affecting vegetative cover and the hydrology and stability of a stream and its parent watershed are key factors influencing the quality of anadromous fish habitat. High intensity storms, drought, soil mass movement, and fire have the greatest impacts. Wind, stream icing, and the influence of insects and disease are important locally...

  18. SOLUBILITIES AND PHYSICAL PROPERTIES OF SATURATED SOLUTIONS IN THE COPPER SULFATE + SULFURIC ACID + SEAWATER SYSTEM AT DIFFERENT TEMPERATURES

    OpenAIRE

    Justel, F. J.; Claros, M.; Taboada, M. E.

    2015-01-01

    Abstract In Chile, the most important economic activity is mining, concentrated in the north of the country. This is a desert region with limited water resources; therefore, the mining sector requires research and identification of alternative sources of water. One alternative is seawater, which can be a substitute of the limited fresh water resources in the region. This work determines the influence of seawater on the solid-liquid equilibrium for acid solutions of copper sulfate at different...

  19. Does the nature of science influence college students' learning of biological evolution?

    Science.gov (United States)

    Butler, Wilbert, Jr.

    This quasi-experimental, mixed-methods study assessed the influence of the nature of science (NOS) instruction on college students' learning of biological evolution. In this research, conducted in two introductory biology courses, in each course the same instruction was employed, with one important exception: in the experimental section students were involved in an explicit, reflective treatment of the nature of science (Explicit, reflective NOS), in the traditional treatment section, NOS was implicitly addressed (traditional treatment). In both sections, NOS aspects of science addressed included is tentative, empirically based, subjective, inferential, and based on relationship between scientific theories and laws. Students understanding of evolution, acceptance of evolution, and understanding of the nature of science were assessed before, during and after instruction. Data collection entailed qualitative and quantitative methods including Concept Inventory for Natural Selection (CINS), Measure of Acceptance of the Theory of Evolution (MATE) survey, Views of nature of Science (VNOS-B survey), as well as interviews, classroom observations, and journal writing to address understand students' views of science and understanding and acceptance of evolution. The quantitative data were analyzed via inferential statistics and the qualitative data were analyzed using grounded theory. The data analysis allowed for the construction and support for four assertions: Assertion 1: Students engaged in explicit and reflective NOS specific instruction significantly improved their understanding of the nature of science concepts. Alternatively, students engaged in instruction using an implicit approach to the nature of science did not improve their understanding of the nature of science to the same degree. The VNOS-B results indicated that students in the explicit, reflective NOS class showed the better understanding of the NOS after the course than students in the implicit NOS class

  20. Influences of Antagonistic Views of Nature on Understanding of Humanity : In the Case of Rousseau and Nietzsche

    OpenAIRE

    宮島, 光志

    2003-01-01

    The aim of this study lies in considering, in the case of Rousseau and Nietzsche, how strongly the antagonistic views of nature influenced the understanding of humanity (human nature). Both Rousseau and Nietzsche criticized the modern European civilization and sought to recover the "nature" in human beings. However, at least, Nietzsche didn't assume that Rousseau was his forerunner. On the contrary, he criticized Rousseau as the greatest enemy. The reason for it can be explained from the diff...

  1. The nuclear energy in the seawater desalination

    International Nuclear Information System (INIS)

    Moreno A, J.; Flores E, R.M.

    2004-01-01

    In general, the hydric resources of diverse regions of the world are insufficient for to satisfy the necessities of their inhabitants. Among the different technologies that are applied for the desalination of seawater are the distillation processes, the use of membranes and in particular recently in development the use of the nuclear energy (Nuclear Desalination; System to produce drinkable water starting from seawater in a complex integrated in that as much the nuclear reactor as the desalination system are in a common location, the facilities and pertinent services are shared, and the nuclear reactor produces the energy that is used for the desalination process). (Author)

  2. Biofouling control of industrial seawater cooling towers

    KAUST Repository

    Albloushi, Mohammed

    2017-11-01

    The use of seawater in cooling towers for industrial applications has much merit in the Gulf Cooperation Council countries due to the scarcity and availability of fresh water. Seawater make-up in cooling towers is deemed the most feasible because of its unlimited supply in coastal areas. Such latent-heat removal with seawater in cooling towers is several folds more efficient than sensible heat extraction via heat exchangers. Operational challenges such as scaling, corrosion, and biofouling are a major challenge in conventional cooling towers, where the latter is also a major issue in seawater cooling towers. Biofouling can significantly hamper the efficiency of cooling towers. The most popular methods used in cooling treatment to control biofouling are disinfection by chlorination. However, the disadvantages of chlorination are formation of harmful disinfection byproducts in the presence of high organic loading and safety concerns in the storage of chlorine gas. In this study, the research focuses on biofouling control in seawater cooling towers by investigating two different approaches. The first strategy addresses the use of alternative oxidants (i.e. ozone micro-bubbles and chlorine dioxide) in treatment of cooling towers. The second strategy investigates removing nutrients in seawater using granular activated carbon filter column and ultrafiltration to prevent the growth of microorganisms. Laboratory bench-scale tests in terms of temperature, cycle of concentration, dosage, etc. indicated that, at lower oxidant dosages (total residual oxidant (TRO) equivalent = 0.1 mg/l Cl2), chlorine dioxide had a better disinfection effect than chlorine and ozone. The performance of oxidizing biocides at pilot scale, operating at assorted conditions, showed that for the disinfectants tested, ozone could remove 95 % bioactivity of total number of bacteria and algae followed by chlorine dioxide at 85%, while conventional chlorine dosing only gave 60% reduction in bioactivities

  3. Flux patterns and membrane fouling propensity during desalination of seawater by forward osmosis

    KAUST Repository

    Li, Zhenyu; Yangali-Quintanilla, Victor; Valladares Linares, Rodrigo; Li, Qingyu; Zhan, Tong; Amy, Gary L.

    2012-01-01

    The membrane fouling propensity of natural seawater during forward osmosis was studied. Seawater from the Red Sea was used as the feed in a forward osmosis process while a 2. M sodium chloride solution was used as the draw solution. The process was conducted in a semi-batch mode under two crossflow velocities, 16.7. cm/s and 4.2. cm/s. For the first time reported, silica scaling was found to be the dominant inorganic fouling (scaling) on the surface of membrane active layer during seawater forward osmosis. Polymerization of dissolved silica was the major mechanism for the formation of silica scaling. After ten batches of seawater forward osmosis, the membrane surface was covered by a fouling layer of assorted polymerized silica clusters and natural organic matter, especially biopolymers. Moreover, the absorbed biopolymers also provided bacterial attachment sites. The accumulated organic fouling could be partially removed by water flushing while the polymerized silica was difficult to remove. The rate of flux decline was about 53% with a crossflow velocity of 16.7. cm/s while reaching more than 70% with a crossflow velocity of 4.2. cm/s. Both concentration polarization and fouling played roles in the decrease of flux. The salt rejection was stable at about 98% during seawater forward osmosis. In addition, an almost complete rejection of natural organic matter was attained. The results from this study are valuable for the design and development of a successful protocol for a pretreatment process before seawater forward osmosis and a cleaning method for fouled membranes. © 2011 Elsevier Ltd.

  4. Seawater-sediment interaction at elevated temperatures and pressures: implications for the near field chemical environment

    International Nuclear Information System (INIS)

    Seyfried, W.E. Jr.; Thornton, E.C.; Janecky, D.R.

    1981-01-01

    Results of four experiments are reported which document chemical exchange and mineralogic modification during seawater-sediment interaction at 200 0 to 300 0 C, 500 bars. Sediments used for this study are from MPG-1 (central North Pacific). Experimental conditions (T, P, W/R) were chosen to be reasonably analogous to conditions which will characterize the near field environment; that is a zone within approximately 1 m of the buried waste canister. In general, the major element chemistry of seawater was similarly modified in all experiments. The aqueous concentrations of Ca, Mg, Sr, and SO 4 decreased and SiO 2 /sub (aq)/, Na, K, and ΣCO 2 increased relative to values in seawater prior to reaction with sediments. pH decreased and remained distinctly acid. Con comitantly significant concentrations of heavy metals entered seawater from the sediments during reaction. Dissolution of Mn-rich phases profoundly affected alteration processes. For example, reaction of MnO 2 components of the smectite-rich sediment (Pacific smectite) with seawater created an unusually oxidizing milieu (fO 2 = 10 -7 74 ), and resulted in dissolution of significant quantities of Au from the reaction cell. Although illite-quartz-Fe-chlorite (sediment B)-seawater interaction also created a relatively oxidizing environment, this environment was not capable of oxidizing Au. Thus, in this regard (oxidation potential) sediment mineralogy exerts a strong influence. Mineralogic modification of sediment B at 200 0 and 300 0 C was minor and characterized by partial dissolution of illite and exchange of Fe for Mg in chlorite. In contrast the smectite-rich sediment, which, prior to reaction with seawater contained a poorly crystalline smectite phase, clinoptilolite, and amorphous material, recrystallized totally to a well defined smectite mineral. Anhydrite was abundantly present amongst the alteration products of all experiments

  5. Fatigue crack growth in welded joints in seawater

    Energy Technology Data Exchange (ETDEWEB)

    Lambert, S.B.

    1988-01-01

    A pipe-to-plate specimen has been developed to study the influence of seawater on the fatigue behaviour of welded tubular joints. DC potential drop techniques have been used to detect fatigue crack initiation, and to monitor the subsequent growth of fatigue cracks. Results for three specimens, tested in air are compared with similar data for tubular and T-plate joints. These comparisons indicate that the pipe/plate is a reasonable model of a tubular joint. Testing was performed on a further six specimens in artificial seawater; two each with free corrosion, optimum cathodic protection, and cathodic overprotection. Fatigue life reduction factors compared with corresponding tests in air were 1.8 and 2.8 for free corrosion, 1.7 and 1.1 with cathodic protection, and 4.2 and 3.3 with cathodic over-protection. These fatigue life reduction factors were comparable to results on T-plate specimens, and were strongly dependent on crack shape development. Linear elastic fracture mechanics techniques appear suitable for the calculation of fatigue crack propagation life. Three approximate solution techniques for crack tip stress intensity factors show reasonable agreement with experimentally derived values. It is recommended that forcing functions be used to model crack aspect ratio development in welded joints. Such forcing functions are influenced by the initial stress distribution and the environment. 207 refs., 192 figs., 22 tabs.

  6. Experimental study of the influence of atmospheric conditions on the performance of natural draft dry cooling towers

    International Nuclear Information System (INIS)

    Markoczy, G.; Staempfli, E.

    1977-08-01

    The heat dissipation of cooling towers is influenced by atmospheric conditions. In order to establish these influences EIR conducted measurements on a natural draft dry cooling tower. During two measuring campaigns with a duration of total 10 weeks the performance of the cooling tower, the ambient air temperatures, the wind velocities and directions as well as air temperature at the top of the tower and in front of the heat exchangers were continuously measured and registered. The results achieved enable the quantitative description of the influence of the ambient air temperature, wind and temperature inversion on the performance of natural draft dry cooling towers. (Auth.)

  7. Impacts of seawater rise on seawater intrusion in the Nile Delta Aquifer, Egypt.

    Science.gov (United States)

    Sefelnasr, Ahmed; Sherif, Mohsen

    2014-01-01

    Several investigations have recently considered the possible impacts of climate change and seawater level rise on seawater intrusion in coastal aquifers. All have revealed the severity of the problem and the significance of the landward movement of the dispersion zone under the condition of seawater level rise. Most of the studies did not consider the possible effects of the seawater rise on the inland movement of the shoreline and the associate changes in the boundary conditions at the seaside and the domain geometry. Such effects become more evident in flat, low land, coastal alluvial plans where large areas might be submerged with seawater under a relatively small increase in the seawater level. None of the studies combined the effect of increased groundwater pumping, due to the possible decline in precipitation and shortage in surface water resources, with the expected landward shift of the shore line. In this article, the possible effects of seawater level rise in the Mediterranean Sea on the seawater intrusion problem in the Nile Delta Aquifer are investigated using FEFLOW. The simulations are conducted in horizontal view while considering the effect of the shoreline landward shift using digital elevation models. In addition to the basic run (current conditions), six different scenarios are considered. Scenarios one, two, and three assume a 0.5 m seawater rise while the total pumping is reduced by 50%, maintained as per the current conditions and doubled, respectively. Scenarios four, five, and six assume a 1.0 m seawater rise and the total pumping is changed as in the first three scenarios. The shoreline is moved to account for the seawater rise and hence the study domain and the seaside boundary are modified accordingly. It is concluded that, large areas in the coastal zone of the Nile Delta will be submerged by seawater and the coast line will shift landward by several kilometers in the eastern and western sides of the Delta. Scenario six represents

  8. Evaluation of the leaching behavior of incineration bottom ash using seawater: A comparison with standard leaching tests.

    Science.gov (United States)

    Lin, Wenlin Yvonne; Heng, Kim Soon; Nguyen, Minh Quan; Ho, Jin Rui Ivan; Mohamed Noh, Omar Ahmad Bin; Zhou, Xue Dong; Liu, Alec; Ren, Fei; Wang, Jing-Yuan

    2017-04-01

    Batch and column tests were conducted on untreated incineration bottom ash (IBA) samples from two incineration plants in Singapore, using seawater as the leachant. The main objective of this study was to investigate the change in the leaching behavior of certain elements (i.e. As, Cd, Cr, Cu, Ni, Pb, Sb, Se and Zn) when IBA comes into contact with seawater. Such an investigation using seawater as leachant was not commonly carried out when investigating leaching behavior in IBA. The leaching tests were then carried out on the same IBA samples using DI water, as a comparison. Lower level of leaching was observed for Pb and Zn when seawater was used as the leachant. Cr and Sb showed significant cumulative release at Liquid-to-Solids (L/S) ratio 5 in the seawater column leaching. The influence of Dissolved Organic Carbon (DOC) on Cu leaching seems to decrease after L/S 2 when using seawater in the column test. Although the leaching behavior of IBA was affected when seawater was used, for the column test, there was no significant difference during the initial release when compared to DI water. The initial L/S fractions collected were important as the low L/S ratios represent the pore water concentration and the maximum output in an actual application. The results from this study would be useful for the future study on using IBA in marine applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Mathematical modelling of a self-polishing antifouling paint exposed to seawater: A parameter study

    DEFF Research Database (Denmark)

    Kiil, Søren; Pedersen, M. S.; Dam-Johansen, Kim

    2002-01-01

    , and to suggest ways of controlling biocide release rates. A case study with an antifouling paint based on the well-known tributyltin self-polishing copolymer system showed that the rate of paint polishing was influenced, to various degrees, by the following parameters: seawater pH and concentration of Na...

  10. Effects of seawater components on radiolysis of water at elevated temperature

    International Nuclear Information System (INIS)

    Wada, Yoichi; Tachibana, Masahiko; Ishida, Kazushige; Ota, Nobuyuki; Shigenaka, Naoto; Inagaki, Hiromitsu; Noda, Hiroshi

    2014-01-01

    Effects of seawater components on radiolysis of water at elevated temperature have been studied with a radiolysis model in order to evaluate influence on integrity of materials used in an ABWR. In 2011, seawater flowed into a wide part of the nuclear power plant system of the Hamaoka Nuclear Power Station Reactor No. 5 owned by Chubu Electric Power Co., Inc. after condenser tubes broke during the plant shutdown operation. The reactor water temperature was 250°C and its maximum Cl − concentration was ca. 450 ppm when seawater was mixed with reactor water. In order to clarify effects of the sea water components on radiolysis of water at elevated temperature, a radiolysis model calculation was conducted with Hitachi's radiolysis analysis code 'SIMFONY'. For the calculation, the temperature range was set from 50 to 250°C with 50°C increments and the gamma dose rate was set at 60 Gys −1 to see the effect of gamma irradiation from fuels under shutdown conditions. Concentrations of radiolytic species were calculated for 10 5 s. Dilution ratio of seawater was changed to see the effects of concentration of seawater components. Reaction rate constants of the Cl − , Br − , HCO 3 − , and SO 4 2− systems were considered. The main radiolytic species were predicted to be hydrogen and oxygen. Hydrogen peroxide of low concentration was produced in seawater-mixed water at elevated temperatures. Compared with these main products, concentrations of radiolytic products originating from chloride ion and other seawater components were found to be rather low. The dominant product among them was ClO 3 − and its concentration was found to be below 0.01ppm at 10 5 s. Then, during the plant shutdown operation, the harmful influence from radiolytic species originating from seawater components on integrity of fuel materials must be smaller than that of chloride ion which is the main ionic species in seawater. (author)

  11. Application of electrochemical impedance spectroscopy to monitor seawater fouling on stainless steels and copper alloys

    International Nuclear Information System (INIS)

    Feron, D.

    1991-01-01

    Electrochemical impedance spectroscopy may be applied to detect and to follow seawater fouling. Experiments have been conducted with natural seawater flowing inside tube-electrodes at temperatures between 30 deg C and 85 deg C. With stainless steel tubes, mineral and organic foulings have been followed; a linear relationship between the dry weight of the organic fouling and its electrical resistance, has been observed. On copper alloy tubes, only mineral deposits have occurred and so have been detected by impedance spectroscopy. (Author). 5 refs., 6 figs

  12. Influence of natural and synthetic carotenoids on the color of egg yolk

    Directory of Open Access Journals (Sweden)

    Fernanda Papa Spada

    2016-06-01

    Full Text Available ABSTRACT Carotenoids are incorporated into the diet of laying hens in order to modify the yolk color. A natural source of carotenoids in tropical countries is annatto, which could be used in the diets of hens. This study aimed to evaluate the addition of natural (annatto and synthetic carotenoids to the diet of laying hens (commercial and alternative and their effects on yolk color and consumer sensory perception of fresh and stored eggs obtained from two different preparations (boiled and fried. Physicochemical analysis of proximate composition, thiobarbituric acid reactive substances (TBARS, emulsion activity and instrumental color were performed. Cooking caused significant alterations to the moisture in the preparations and this may have directly affected the color intensity, influencing factors related to egg appearance. In this study, 85 % of the panelists indicated that yolk color is an important attribute of the product’s quality. There was no antioxidant effect of the carotenoids in raw eggs. Synthetic additives should be better dosed to obtain the desired effect. Storage did not alter the proximate composition of the eggs.

  13. The Influence of Exposure to Natural Disasters on Depression and PTSD Symptoms among Firefighters.

    Science.gov (United States)

    Pennington, Michelle L; Carpenter, Thomas P; Synett, Samantha J; Torres, Victoria A; Teague, Jennifer; Morissette, Sandra B; Knight, Jeffrey; Kamholz, Barbara W; Keane, Terence M; Zimering, Rose T; Gulliver, Suzy B

    2018-02-01

    Introduction Firefighters represent an important population for understanding the consequences of exposure to potentially traumatic stressors. Hypothesis/Problem The researchers were interested in the effects of pre-employment disaster exposure on firefighter recruits' depression and posttraumatic stress disorder (PTSD) symptoms during the first three years of fire service and hypothesized that: (1) disaster-exposed firefighters would have greater depression and PTSD symptoms than non-exposed overall; and (2) depression and PTSD symptoms would worsen over years in fire service in exposed firefighters, but not in their unexposed counterparts. In a baseline interview, 35 male firefighter recruits from seven US cities reported lifetime exposure to natural disaster. These disaster-exposed male firefighter recruits were matched on age, city, and education with non-exposed recruits. A generalized linear mixed model revealed a significant exposure×time interaction (e coef =1.04; Pdisaster exposure only. This pattern persisted after controlling for social support from colleagues (e coefficient=1.05; Pdisaster exposure only, even after controlling for social support. Posttraumatic stress disorder symptoms did not vary between exposure groups. Pennington ML , Carpenter TP , Synett SJ , Torres VA , Teague J , Morissette SB , Knight J , Kamholz BW , Keane TM , Zimering RT , Gulliver SB . The influence of exposure to natural disasters on depression and PTSD symptoms among firefighters. Prehosp Disaster Med. 2018;33(1):102-108.

  14. Influences of buoyancy and thermal boundary conditions on heat transfer with naturally-induced flow

    International Nuclear Information System (INIS)

    Jackson, J.D.; Li, J.

    2002-01-01

    A fundamental study is reported of heat transfer from a vertical heated tube to air which is induced naturally upwards through it by the action of buoyancy. Measurements of local heat transfer coefficient were made using a specially designed computer-controlled power supply and measurement system for conditions of uniform wall temperature and uniform wall heat flux. The effectiveness of heat transfer proved to be much lower than for conditions of forced convection. It was found that the results could be correlated satisfactorily when presented in terms of dimensionless parameters similar to those used for free convection heat transfer from vertical surfaces provided that the heat transfer coefficients were evaluated using local fluid bulk temperature calculated utilising the measured values of flow rate induced through the system. Additional experiments were performed' with pumped flow. These covered the entire mixed convection region. It was found that the data for naturally-induced flow mapped onto the pumped flow data when presented in terms of Nusselt number ratio (mixed to forced) and buoyancy parameter. Computational simulations of the experiments were performed using an advanced computer code which incorporated a buoyancy-influenced, variable property, developing wall shear flow formulation and a low Reynolds number k-ε turbulence model. These reproduced observed behaviour quite well. (author)

  15. Influence of natural sorbents in immobilization of radioactive waste in cement

    International Nuclear Information System (INIS)

    Plecas, I.; Dimovic, S.

    2006-01-01

    Leach characteristics of 137 Cs and 60 Co radionuclides from spent mix bead ion exchange resins and both ordinary Portland cement and cement mixed with two kind of natural sorbents, (bentonite and clinoptilolite) have been studied using International Atomic Energy's (IAEA) standard leach method. A study is undertaken to determine the waste immobilization performance of low-level wastes in cement-natural sorbents mixtures. The solidification matrix was a standard Portland cement mixed with 290-350 (kg/m 3 ) spent mix bead exchange resins, with or without 1-10 % of bentonite or/and clinoptilolite The leaching rates from the cement-bentonite matrix as 60 Co: (1.20-9.72)x10 -5 (cm/d) and for 137 Cs: (1.00-9.22)x10 -4 (cm/d), after 300 days were measured. From the leaching data the apparent diffusivity of cobalt and cesium in cement bentonite or/and clinoptilolite matrix with a waste load of 350 (kg/m 3 ) spent mix bead exchange resins was measured as 60 Co: (1.0-5.9)x10 -6 (cm 2 /d) and for 137 Cs: (0.48-2.4)x10 -4 (cm 2 /d) after 300 days. The compressive strength of these samples is determined following the ASTM standards. These results are part of a 30-year mortar and concrete testing project which will influence the design of radioactive waste management for a future Serbian radioactive waste disposal center. (author)

  16. Regulatory frameworks for Natural Gas DSM in Canada : exploring design options, influences and characteristics of success

    International Nuclear Information System (INIS)

    Simon, J.

    2005-11-01

    There are 6 natural gas distribution companies in Canada with formal, ratepayer-funded demand side management (DSM) programs. However, the general characteristics and regulatory environment of these companies varies greatly. With the exception of Enbridge Gas and Union Gas, each company is located in a different province, which means that companies face different energy regulations and energy efficiency policies. An introduction to DSM and its regulation in Canada was presented, as well as an overview of common models in Canada, and the general considerations involved in designing a regulatory framework were discussed. Regulatory design options for natural gas demand-side management regulatory frameworks were evaluated. The major factors that influence the frameworks were analyzed, and the characteristics of a successful DSM program were outlined. The research methodology for this paper consisted of telephone interviews with policy-makers, regulators, non-governmental organizations and regulatory affairs personnel from local distribution companies. Results indicated the importance of a clear policy framework that provides direction for DSM designers. The common elements for a successful regulatory framework were considered to be a systems approach to the definition of DSM; clear regulatory rules; a long-term predictable source and level of DSM funding that reflected the maturity of the DSM market; an alignment of government energy policies and DSM regulatory frameworks; and recognition and capturing of the broad range of DSM benefits

  17. Understanding Factors That Influence Stakeholder Trust of Natural Resource Science and Institutions

    Science.gov (United States)

    Gray, Steven; Shwom, Rachael; Jordan, Rebecca

    2012-03-01

    Building trust between resource users and natural resource institutions is essential when creating conservation policies that rely on stakeholders to be effective. Trust can enable the public and agencies to engage in cooperative behaviors toward shared goals and address shared problems. Despite the increasing attention that trust has received recently in the environmental management literature, the influence that individual cognitive and behavioral factors may play in influencing levels of trust in resource management institutions, and their associated scientific assessments, remains unclear. This paper uses the case of fisheries management in the northeast to explore the relationships between an individual's knowledge of the resource, perceptions of resource health, and participatory experience on levels of trust. Using survey data collected from 244 avid recreational anglers in the Northeast U.S., we test these relationships using structural equation modeling. Results indicate that participation in fisheries management is associated with increased trust across all aspects of fisheries management. In addition, higher ratings of resource health by anglers are associated with higher levels of trust of state and regional institutions, but not federal institutions or scientific methods.

  18. Influence of dams on sediment continuity: A study case of a natural metallic contamination.

    Science.gov (United States)

    Frémion, Franck; Bordas, François; Mourier, Brice; Lenain, Jean-François; Kestens, Tim; Courtin-Nomade, Alexandra

    2016-03-15

    Sediments play an important role on the quality of aquatic ecosystems, notably in the reservoir areas where they can either be a sink or a source of contaminants, depending on the management and hydrological conditions. The physicochemical properties of 25 surface sediments samples of a reservoir catchment (Vaussaire, Cantal, France) were studied. Results show a strong influence of dam presence, notably on the grain size and organic matter (OM) contents. The concentrations of trace metals and metalloids (As, Cd, Cr, Cu, Ni, Pb and Zn) were also measured and compared with worldwide reservoir concentrations and international sediment quality guideline levels in order to assess the intensity of the metallic contamination. Cr and Ni are the trace elements presenting the significantly highest values at the catchment scale. Enrichment Factors (EF), calculated using both local and national backgrounds, show that metals have mainly a natural origin, explaining especially the Cr and Ni values, linked with the composition of parental rocks. Unexpectedly, all the observed metal concentrations are lower in the reservoir than upstream and downstream, which might be related to the high fresh OM inputs in the reservoir, diluting the global metallic contamination. Multivariate statistical analyses, carried out in order to identify the relationship between the studied metals and sediment characteristics, tend to support this hypothesis, confirming the unusually low influence of such poorly-degraded OM on trace element accumulation in the reservoir. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Decadal changes in the structure of Cymodocea nodosa seagrass meadows: Natural vs. human influences

    Science.gov (United States)

    Tuya, Fernando; Ribeiro-Leite, Luís; Arto-Cuesta, Noelia; Coca, Josep; Haroun, Ricardo; Espino, Fernando

    2014-01-01

    Seagrass meadows are deteriorating worldwide. However, numerous declines are still unreported, which avoid accurate evaluations of seagrass global trends. This is particularly relevant for the western African coast and nearby oceanic archipelagos in the eastern Atlantic. The seagrass Cymodocea nodosa is an 'ecological engineer' on shallow soft bottoms of the Canary Islands. A comparative decadal study was conducted in 21 C. nodosa seagrass meadows at Gran Canaria Island to compare the structure (shoot density, leaf length and cover) between 2003 and 2012. Overall, 11 meadows exhibited a severe regression, while 10 remained relatively stable. During this period, natural influences (sea surface temperature, Chlorophyll-a concentration and PAR light, as well as the number of storm episodes detaching seagrasses) had a low predictive power on temporal patterns in seagrass structure. In contrast, proximity from a range of human-mediated influences (e.g. the number of outfalls and ports) seem to be related to the loss of seagrass; the rate of seagrass erosion between 2003 and 2012 was significantly predicted by the number of human-mediated impacts around each meadow. This result highlights promoting management actions to conserve meadows of C. nodosa at the study region through efficient management of local impacts.

  20. Soil and vegetation influence in plants natural radionuclides uptake at a uranium mining site

    Science.gov (United States)

    Charro, E.; Moyano, A.

    2017-12-01

    The main objective of this work is to investigate the uptake of several radionuclides by the vegetation characteristic of a dehesa ecosystem in uranium mining-impacted soils in Central-West of Spain. The activity concentration for 238U, 226Ra, 210Pb, 232Th, and 224Ra was measured in soil and vegetation samples using a Canberra n-type HPGe gamma-ray spectrometer. Transfer factors of natural radionuclides in different tissues (leaves, branches, twigs, and others) of native plants were evaluated. From these data, the influence of the mine, the physicochemical parameters of the soils and the type of vegetation were analyzed in order to explain the accumulation of radionuclides in the vegetation. A preferential uptake of 210Pb and 226Ra by plants, particularly by trees of the Quercus species (Quercus pyrenaica and Quercus ilex rotundifolia), has been observed, being the transfer factors for 226Ra and 210Pb in these tree species higher than those for other plants (like Pinus pinaster, Rubur ulmifolius and Populus sp.). The analysis of radionuclide contents and transfer factors in the vegetation showed no evidence of influence of the radionuclide concentration in soils, although it could be explained in terms of the type of plants and, in particular, of the tree's species, with special attention to the tree's rate of growth, being higher in slow growing species.

  1. Eastern naturalness versus western artificiality: Rimsky Korsakov's influence on Manoles Kalomoires' early operas

    Directory of Open Access Journals (Sweden)

    Romanou Aikaterini

    2005-01-01

    Full Text Available In this article the writer investigates the relations between perceptions of the East and the West in nineteenth century Greece, their connection to national identity, to the language question and to political tendencies. The composer Manoles Kalomoires was influenced by a group of progressive intellectuals striving to liberate Greek literature and language from its dependence on Ancient Greek legacy, a dependence motivated by Western idealists (who saw in the Greek Revolution of 1821 a renaissance of Ancient Greece. Most were educated in the West, but promoted an oriental image of Greeks. Kalomoires' musical expression of this image was inspired by Rimsky-Korsakov's Sheherazade and the Golden Cockerel. In 1909-910 he wrote an unfinished opera, Mavrianos and the King, on the model of the Golden Cockerel. He later used this music in his best known opera, The Mother's Ring (1917. In the present article the similarities in the three works are for the first time shown. An essential influence from Rimsky-Korsakov's work is the contrast between the world of freedom, nature and fantasy and that of oppression.

  2. Child and adolescent fast-food choice and the influence of calorie labeling: a natural experiment.

    Science.gov (United States)

    Elbel, B; Gyamfi, J; Kersh, R

    2011-04-01

    Obesity is an enormous public health problem and children have been particularly highlighted for intervention. Of notable concern is the fast-food consumption of children . However, we know very little about how children or their parents make fast-food choices, including how they respond to mandatory calorie labeling. We examined children's and adolescents' fast-food choice and the influence of calorie labels in low-income communities in New York City (NYC) and in a comparison city (Newark, NJ). Natural experiment: Survey and receipt data were collected from low-income areas in NYC, and Newark, NJ (as a comparison city), before and after mandatory labeling began in NYC. Study restaurants included four of the largest chains located in NYC and Newark: McDonald's, Burger King, Wendy's and Kentucky Fried Chicken. A total of 349 children and adolescents aged 1-17 years, who visited the restaurants with their parents (69%) or alone (31%) before or after labeling was introduced. In total, 90% were from racial or ethnic minority groups. We found no statistically significant differences in calories purchased before and after labeling; many adolescents reported noticing calorie labels after their introduction (57% in NYC) and a few considered the information when ordering (9%). Approximately 35% of adolescents ate fast food six or more times per week and 72% of adolescents reported that taste was the most important factor in their meal selection. Adolescents in our sample reported that parents have some influence on their meal selection. Adolescents in low-income communities notice calorie information at similar rates as adults, although they report being slightly less responsive to it than adults. We did not find evidence that labeling influenced adolescent food choice or parental food choices for children in this population.

  3. Influence of mineralogical and heavy metal composition on natural radionuclide concentrations in the river sediments

    Energy Technology Data Exchange (ETDEWEB)

    Suresh, G., E-mail: gsureshphy_1983@yahoo.co.in [Department of Physics Thiruvalluvar College of Engg and Tech, Ponnur hills, Vandavasi, Tamilnadu 604 505 (India); Ramasamy, V. [Department of Physics, Annamalai University, Tamilnadu (India); Meenakshisundaram, V. [Health and Safety Division, IGCAR, Kalpakkam, Tamilnadu (India); Venkatachalapathy, R. [CAS in Marine Biology, Faculty of Marine Sciences, Annamalai University, Tamilnadu (India); Ponnusamy, V. [Department of Physics, MIT Campus, Anna University Chennai, Tamilnadu (India)

    2011-10-15

    The natural radiation level has been determined for the sediment samples of the Ponnaiyar River with an aim of evaluating the radiation hazard. The mineralogical characterizations of the sediments have been carried out using the Fourier Transform Infrared (FTIR) spectroscopic technique. The relative distribution of major minerals is determined by calculating extinction coefficient. The concentration and spatial distribution of heavy metals (Pb, Cr, Cu, Zn and Ni) have been studied to understand the heavy metal contamination and its level of toxicity. To evaluate the potential toxicity, heavy metal concentrations are compared with different toxicological and geological reference values. The comparison results suggest that the present metals create an adverse effect on the aquatic ecosystems associated with this river. To assess the sediment contamination due to the studied heavy metals, the Pollution Load Index (PLI) is calculated. Multivariate Statistical analyses (Pearson Correlation, Cluster and Factor analysis) were carried out between the parameters obtained from radioactivity, mineralogical and geochemical analysis to know the existing relations. Obtained results showed that the effect of mineralogy on level of radioactivity should be significant. However, mineralogy effect on heavy metal composition in the sediments should be limited, indicating that other factors such as vicinity of the pollution sources are more important. Also, the influence of mineralogical characterization on level of radioactivity is significant, whereas the influence of the heavy metal composition on level of radioactivity should be limited. - Highlights: >Sediments radioactivity, mineralogical and heavy metal characterization have been analyzed. > Absorbed dose rate, PLI and kaolinite increase towards the river mouth. > Influence of minerals and heavy metals on level of radioactivity is assessed.

  4. Influence of mineralogical and heavy metal composition on natural radionuclide concentrations in the river sediments

    International Nuclear Information System (INIS)

    Suresh, G.; Ramasamy, V.; Meenakshisundaram, V.; Venkatachalapathy, R.; Ponnusamy, V.

    2011-01-01

    The natural radiation level has been determined for the sediment samples of the Ponnaiyar River with an aim of evaluating the radiation hazard. The mineralogical characterizations of the sediments have been carried out using the Fourier Transform Infrared (FTIR) spectroscopic technique. The relative distribution of major minerals is determined by calculating extinction coefficient. The concentration and spatial distribution of heavy metals (Pb, Cr, Cu, Zn and Ni) have been studied to understand the heavy metal contamination and its level of toxicity. To evaluate the potential toxicity, heavy metal concentrations are compared with different toxicological and geological reference values. The comparison results suggest that the present metals create an adverse effect on the aquatic ecosystems associated with this river. To assess the sediment contamination due to the studied heavy metals, the Pollution Load Index (PLI) is calculated. Multivariate Statistical analyses (Pearson Correlation, Cluster and Factor analysis) were carried out between the parameters obtained from radioactivity, mineralogical and geochemical analysis to know the existing relations. Obtained results showed that the effect of mineralogy on level of radioactivity should be significant. However, mineralogy effect on heavy metal composition in the sediments should be limited, indicating that other factors such as vicinity of the pollution sources are more important. Also, the influence of mineralogical characterization on level of radioactivity is significant, whereas the influence of the heavy metal composition on level of radioactivity should be limited. - Highlights: →Sediments radioactivity, mineralogical and heavy metal characterization have been analyzed. → Absorbed dose rate, PLI and kaolinite increase towards the river mouth. → Influence of minerals and heavy metals on level of radioactivity is assessed.

  5. Child and adolescent fast-food choice and the influence of calorie labeling: a natural experiment

    Science.gov (United States)

    Elbel, B; Gyamfi, J; Kersh, R

    2013-01-01

    Objective Obesity is an enormous public health problem and children have been particularly highlighted for intervention. Of notable concern is the fast-food consumption of children. However, we know very little about how children or their parents make fast-food choices, including how they respond to mandatory calorie labeling. We examined children’s and adolescents’ fast-food choice and the influence of calorie labels in low-income communities in New York City (NYC) and in a comparison city (Newark, NJ). Design Natural experiment: Survey and receipt data were collected from low-income areas in NYC, and Newark, NJ (as a comparison city), before and after mandatory labeling began in NYC. Study restaurants included four of the largest chains located in NYC and Newark: McDonald’s, Burger King, Wendy’s and Kentucky Fried Chicken. Subjects A total of 349 children and adolescents aged 1–17 years who visited the restaurants with their parents (69%) or alone (31%) before or after labeling was introduced. In total, 90% were from racial or ethnic minority groups. Results We found no statistically significant differences in calories purchased before and after labeling; many adolescents reported noticing calorie labels after their introduction (57% in NYC) and a few considered the information when ordering (9%). Approximately 35% of adolescents ate fast food six or more times per week and 72% of adolescents reported that taste was the most important factor in their meal selection. Adolescents in our sample reported that parents have some influence on their meal selection. Conclusions Adolescents in low-income communities notice calorie information at similar rates as adults, although they report being slightly less responsive to it than adults. We did not find evidence that labeling influenced adolescent food choice or parental food choices for children in this population. PMID:21326209

  6. Simulation of seawater intrusion in coastal aquifers: Some typical ...

    Indian Academy of Sciences (India)

    Springer Verlag Heidelberg #4 2048 1996 Dec 15 10:16:45

    Seawater intrusion; coastal aquifers; density-dependent flow and ... The seawater intrusion mechanism in coastal aquifers generally causes the occurrence of ... (4) The dynamic viscosity of the fluid does not change with respect to salinity and.

  7. Biologically mediated dissolution of volcanic glass in seawater

    NARCIS (Netherlands)

    Staudigel, H; Yayanos, A; Chastain, R; Davies, G.T.; Verdurmen, E.A Th; Schiffmann, P; Bourcier, R; de Baar, H.J.W.

    1998-01-01

    We studied the effects of biological mediation on the dissolution of basaltic glass in seawater. Experiments with typical seawater microbial populations were contrasted with a sterile control, and reactions were monitored chemically and isotopically. Biologically mediated experiments produce twice

  8. Stabilization of arsenic and lead by magnesium oxide (MgO) in different seawater concentrations.

    Science.gov (United States)

    Kameda, Kentaro; Hashimoto, Yohey; Ok, Yong Sik

    2018-02-01

    Ongoing sea level rise will have a major impact on mobility and migration of contaminants by changing a number of natural phenomena that alter geochemistry and hydrology of subsurface environment. In-situ immobilization techniques may be a promising remediation strategy for mitigating contaminant mobility induced by sea level rise. This study investigated the reaction mechanisms of magnesium oxide (MgO) with aqueous Pb and As under freshwater and seawater using XAFS spectroscopy. Initial concentrations of Pb and As in freshwater strongly controlled the characteristics of the reaction product of MgO. Our study revealed that i) the removal of aqueous Pb and As by MgO was increased by the elevation of seawater concentration, and ii) the removal of As was attributed primarily to (inner-sphere) surface adsorption on MgO, independent on seawater concentrations, and iii) the retention mechanism of Pb was dependent on seawater concentrations where formations of Pb oxides and adsorption on the MgO surface were predominant in solutions with low and high salinity, respectively. The release of As fixed with MgO significantly increased in seawater compared to freshwater, although the amount of As desorbed accounted for <0.2% of total As. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Survival behaviour and virulence of the fish pathogen Vibrio ordalii in seawater microcosms.

    Science.gov (United States)

    Ruiz, Pamela; Poblete-Morales, Matías; Irgang, Rute; Toranzo, Alicia E; Avendaño-Herrera, Ruben

    2016-06-15

    Vibrio ordalii, the causative agent of atypical vibriosis, is a Gram-negative, motile, rod-shaped bacterium that severely affects the salmonid aquaculture industry. V. ordalii has been biochemically, antigenically and genetically characterized. However, studies on the survival behaviour of this bacterium in aquatic environments are scarce, and there is no information regarding its disease transmission and infectious abilities outside of the fish host or regarding water as a possible reservoir. The present study investigated the survival behaviour of V. ordalii Vo-LM-06 and Vo-LM-18 in sterile and non-sterile seawater microcosms. After a year in sterile seawater without nutrients, 1% of both V. ordalii strains survived (~10(3) colony-forming units ml(-1)), and long-term maintenance did not affect bacterial biochemical or genetic properties. Additionally, V. ordalii maintained for 60 d in sterile seawater remained infective in rainbow trout Oncorhynchus mykiss. However, after 2 d of natural seawater exposure, this bacterium became non-culturable, indicating that autochthonous microbiota may play an important role in survival. Recuperation assays that added fresh medium to non-sterile microcosms did not favour V. ordalii recovery on solid media. Our results contribute towards a better understanding of V. ordalii survival behaviour in seawater ecosystems.

  10. Construction of the seawater 87Sr/86Sr curve for the Cenozoic and Cretaceous: supporting data

    International Nuclear Information System (INIS)

    Koepnick, R.B.; Burke, W.H.; Denison, R.E.; Hetherington, E.A.; Nelson, H.F.; Otto, J.B.; Waite, L.E.

    1985-01-01

    We present the data used to construct the Cenozoic and Cretaceous portion of the Phanerozoic curve of seawater 87 Sr/ 86 Sr that had been given in summary form by W.H. Burke and coworkers. All Cenozoic samples (128) and 22 Cretaceous samples are foram-nannofossil oozes and limestones from DSDP cores distributed among 13 sites in the Atlantic, Pacific and Indian Oceans, and the Caribbean Sea. Non-DSDP Cretaceous samples (126) include limestone, anhydrite and phosphate samples from North America, Europe and Asia. Determination of the 87 Sr/ 86 Sr value of seawater at particular times in the past is based on comparison of ratios derived from coeval marine samples from widely separated geographic areas. The general configuration of the Cenozoic and Cretaceous curve appears to be strongly influenced by the history of plate interactions and sea-floor spreading. Specific rises and falls in the 87 Sr/ 86 Sr of seawater, however, may be caused by a variety of factors such as variation in lithologic composition of the crust exposed to weathering, configuration and topographic relief of continents, volcanic activity, rate of sea-floor spreading, extent of continental inundation by epeiric seas, and variations in both climate and paleo-oceanographic conditions. Many or all of these factors are probably related to global tectonic processes, yet their combined effect on the temporal variation of seawater 87 Sr/ 86 Sr can complicate a direct plate-tectonic interpretation for portions of the seawater curve. (Auth.)

  11. An exploratory study on seawater-catalysed urine phosphorus recovery (SUPR).

    Science.gov (United States)

    Dai, Ji; Tang, Wen-Tao; Zheng, Yi-Se; Mackey, Hamish R; Chui, Ho Kwong; van Loosdrecht, Mark C M; Chen, Guang-Hao

    2014-12-01

    Phosphorus (P) is a crucial and non-renewable resource, while it is excessively discharged via sewage, significant amounts originating from human urine. Recovery of P from source-separated urine presents an opportunity not only to recover this precious resource but also to improve downstream sewage treatment works. This paper proposes a simple and economic method to recover urine derived P by using seawater as a low-cost precipitant to form struvite, as Hong Kong has practised seawater toilet flushing as an alternative water resource since 1958. Chemical reactions, process conditions and precipitate composition for P precipitation in urine have been investigated to develop this new urine P recovery approach. This study concluded that ureolysis extent in a urine-seawater mixture determines the reaction pH that in turn influences the P recovery efficiency significantly; 98% of urine P can precipitate with seawater within 10 min when 40-75% of the urea in urine is ureolysed; the urine to seawater ratio alters the composition of the precipitates. The P content in the precipitates was found to be more than 9% when the urine fraction was 40% or higher. Magnesium ammonium phosphate (MAP) was confirmed to be the predominant component of the precipitates. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Innovative Elution Processes for Recovering Uranium from Seawater

    International Nuclear Information System (INIS)

    Wai, Chien; Tian, Guoxin; Janke, Christopher

    2014-01-01

    Utilizing amidoxime-based polymer sorbents for extraction of uranium from seawater has attracted considerable interest in recent years. Uranium collected in the sorbent is recovered typically by elution with an acid. One drawback of acid elution is deterioration of the sorbent which is a significant factor that limits the economic competitiveness of the amidoxime-based sorbent systems for sequestering uranium from seawater. Developing innovative elution processes to improve efficiency and to minimize loss of sorbent capacity become essential in order to make this technology economically feasible for large-scale industrial applications. This project has evaluated several elution processes including acid elution, carbonate elution, and supercritical fluid elution for recovering uranium from amidoxime-based polymer sorbents. The elution efficiency, durability and sorbent regeneration for repeated uranium adsorption- desorption cycles in simulated seawater have been studied. Spectroscopic techniques are used to evaluate chemical nature of the sorbent before and after elution. A sodium carbonate-hydrogen peroxide elution process for effective removal of uranium from amidoxime-based sorbent is developed. The cause of this sodium carbonate and hydrogen peroxide synergistic leaching of uranium from amidoxime-based sorbent is attributed to the formation of an extremely stable uranyl peroxo-carbonato complex. The efficiency of uranium elution by the carbonate-hydrogen peroxide method is comparable to that of the hydrochloric acid elution but damage to the sorbent material is much less for the former. The carbonate- hydrogen peroxide elution also does not need any elaborate step to regenerate the sorbent as those required for hydrochloric acid leaching. Several CO2-soluble ligands have been tested for extraction of uranium from the sorbent in supercritical fluid carbon dioxide. A mixture of hexafluoroacetylacetone and tri-n-butylphosphate shows the best result but uranium

  13. Innovative Elution Processes for Recovering Uranium from Seawater

    Energy Technology Data Exchange (ETDEWEB)

    Wai, Chien [Univ. of Idaho, Moscow, ID (United States); Tian, Guoxin [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Janke, Christopher [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2014-05-29

    Utilizing amidoxime-based polymer sorbents for extraction of uranium from seawater has attracted considerable interest in recent years. Uranium collected in the sorbent is recovered typically by elution with an acid. One drawback of acid elution is deterioration of the sorbent which is a significant factor that limits the economic competitiveness of the amidoxime-based sorbent systems for sequestering uranium from seawater. Developing innovative elution processes to improve efficiency and to minimize loss of sorbent capacity become essential in order to make this technology economically feasible for large-scale industrial applications. This project has evaluated several elution processes including acid elution, carbonate elution, and supercritical fluid elution for recovering uranium from amidoxime-based polymer sorbents. The elution efficiency, durability and sorbent regeneration for repeated uranium adsorption- desorption cycles in simulated seawater have been studied. Spectroscopic techniques are used to evaluate chemical nature of the sorbent before and after elution. A sodium carbonate-hydrogen peroxide elution process for effective removal of uranium from amidoxime-based sorbent is developed. The cause of this sodium carbonate and hydrogen peroxide synergistic leaching of uranium from amidoxime-based sorbent is attributed to the formation of an extremely stable uranyl peroxo-carbonato complex. The efficiency of uranium elution by the carbonate-hydrogen peroxide method is comparable to that of the hydrochloric acid elution but damage to the sorbent material is much less for the former. The carbonate- hydrogen peroxide elution also does not need any elaborate step to regenerate the sorbent as those required for hydrochloric acid leaching. Several CO2-soluble ligands have been tested for extraction of uranium from the sorbent in supercritical fluid carbon dioxide. A mixture of hexafluoroacetylacetone and tri-n-butylphosphate shows the best result but uranium

  14. Concentration of uranium in seawater by flotation

    International Nuclear Information System (INIS)

    Nozaki, Toru; Yamashita, Hiroshi

    1986-01-01

    A method has been developed for the concentration of uranium in seawater by precipitation flotation-carbonate extraction-ion flotation. Uranium in seawater was coprecipitated with hydrated iron (III) oxide by adjusting the pH to 5.5 after addition of 1.0 x 10 -3 mol/l of iron (III) and agitating for 1 hr, and the precipitate was floated with 1.0 x 10 -5 mol/l of sodium oleate and 5.0 x 10 -5 mol/l of sodium lauryl sulfate by bubbling nitrogen through the seawater for 15 min. Uranium was extracted from the precipitate scum at the yield of 89 % with 100 ml of 1.8 % of ammonium carbonate solution by agitating for 2 hr, and floated with 1.2 x 10 -3 mol/l of cetylpyridinium chloride by bubbling nitrogen through the extract diluted 5-fold for 30 min in the recovery of about 100 %. The fairly selective recovery of uranium was obtained from 4 l of seawater at the yield of 87 % throughout the entire process. (author)

  15. Biofouling control of industrial seawater cooling towers

    KAUST Repository

    Al-Bloushi, Mohammed

    2017-01-01

    In this study, the research focuses on biofouling control in seawater cooling towers by investigating two different approaches. The first strategy addresses the use of alternative oxidants (i.e. ozone micro-bubbles and chlorine dioxide) in treatment of cooling towers. The second strategy investigates removing nutrients in seawater using granular activated carbon filter column and ultrafiltration to prevent the growth of microorganisms. Laboratory bench-scale tests in terms of temperature, cycle of concentration, dosage, etc. indicated that, at lower oxidant dosages (total residual oxidant (TRO) equivalent = 0.1 mg/l Cl2), chlorine dioxide had a better disinfection effect than chlorine and ozone. The performance of oxidizing biocides at pilot scale, operating at assorted conditions, showed that for the disinfectants tested, ozone could remove 95 % bioactivity of total number of bacteria and algae followed by chlorine dioxide at 85%, while conventional chlorine dosing only gave 60% reduction in bioactivities. Test results of GAC bio-filter showed that around 70 % removal of total organic carbon in the seawater feed was achieved and was effective in keeping the microbial growth to a minimum. The measured results from this study enable designers of seawater cooling towers to manage the biofouling problems when such cooling towers are extrapolated to a pilot scale.

  16. Durability of high performance concrete in seawater

    International Nuclear Information System (INIS)

    Amjad Hussain Memon; Salihuddin Radin Sumadi; Rabitah Handan

    2000-01-01

    This paper presents a report on the effects of blended cements on the durability of high performance concrete (HPC) in seawater. In this research the effect of seawater was investigated. The specimens were initially subjected to water curing for seven days inside the laboratory at room temperature, followed by seawater curing exposed to tidal zone until testing. In this study three levels of cement replacement (0%, 30% and 70%) were used. The combined use of chemical and mineral admixtures has resulted in a new generation of concrete called HPC. The HPC has been identified as one of the most important advanced materials necessary in the effort to build a nation's infrastructure. HPC opens new opportunities in the utilization of the industrial by-products (mineral admixtures) in the construction industry. As a matter of fact permeability is considered as one of the fundamental properties governing the durability of concrete in the marine environment. Results of this investigation indicated that the oxygen permeability values for the blended cement concretes at the age of one year are reduced by a factor of about 2 as compared to OPC control mix concrete. Therefore both blended cement concretes are expected to withstand in the seawater exposed to tidal zone without serious deterioration. (Author)

  17. A Survey of Tritium in Irish Seawater

    International Nuclear Information System (INIS)

    Currivan, L.; Kelleher, K.; McGinnity, P.; Wong, J.; McMahon, C.

    2013-07-01

    This report provides a comprehensive record of the study and measurements of tritium in Irish seawater undertaken by the Radiological Protection Institute of Ireland RPII. The majority of the samples analysed were found to have tritium concentrations below the limit of detection and a conservative assessment of radiation dose arising showed a negligible impact to the public. Tritium is discharged in large quantities from various nuclear facilities, and mostly in liquid form. For this reason it is included in the list of radioactive substances of interest to the OSPAR (Oslo-Paris) Convention to protect the marine environment of the North-East Atlantic. To fulfil its role within OSPAR, to provide technical support to the Irish Government, RPII carried out a project to determine the levels of tritium in seawater from around the Irish coast to supplement its routine marine monitoring programme. A total of 85 seawater samples were collected over a three year period and analysed at the RPII's laboratory. Given that the operational discharges for tritium from the nuclear fuel reprocessing plant at Sellafield, UK, are expected to increase due to current and planned decommissioning activities RPII will continue to monitor tritium levels in seawater around the Irish coast, including the Irish Sea, as part of its routine marine monitoring programme

  18. The Influence of Explicit Nature of Science and Argumentation Instruction on Preservice Primary Teachers' Views of Nature of Science

    Science.gov (United States)

    McDonald, Christine V.

    2010-01-01

    There exists a general consensus in the science education literature around the goal of enhancing learners' views of nature of science (NOS). An extensive body of research in the field has highlighted the effectiveness of explicit NOS instructional approaches in improving learners' NOS views. Emerging research has suggested that engaging learners…

  19. Operational problems related to the preparation of the seawater soluble fraction of crude oil.

    Science.gov (United States)

    Ziolli, Roberta L; Jardim, Wilson F

    2002-02-01

    Owing to the importance of dissolution and weathering processes following oil spills, this work focused on the operational (quantitative) aspects related to the dissolution of petroleum-derived products, as well as the influence of solar light on both dissolution and the photoproduction of hydrogen peroxide. Four Brazilian crude oil samples were used to study the transfer process of organic compounds from the crude oil film to the aqueous phase (natural seawater) over a period of up to 45 days. Dissolved organic carbon (DOC), measured by non-dispersive infrared spectroscopy followed by high temperature catalytic combustion, was used to follow the partitioning between the two phases. Aqueous DOC values increased as a function of time (up to 15 days) until equilibrium was reached at concentrations ranging from 5 to 45 mg C L(-1). The final DOC concentration as well as the rate of dissolution depends on the nature of the crude oil. When exposed to sunlight, the dissolution was enhanced by up to 67.3%, and inorganic peroxides were generated in the concentration range from 4.5 up to 8.0 micromol L(-1) after 7.3 h irradiation. These results indicate that there is a need for a standard procedure for the production of the WSF in order to generate a more reliable tool to assess the impact of oil spills on the marine environment.

  20. Influence of solar activity and environment on 10Be in recent natural archives

    International Nuclear Information System (INIS)

    Berggren, Ann-Marie

    2009-01-01

    Understanding the link between the Sun and climate is vital in the current incidence of global climate change, and 10 Be in natural archives constitutes an excellent tracer for this purpose. As cosmic rays enter the atmosphere, cosmogenic isotopes like 10 Be and 14 C are formed. Variations in solar activity modulate the amount of incoming cosmic rays, and thereby cosmogenic isotope production. Atmospherically produced 10 Be enters natural archives such as sediments and glaciers by wet and dry deposition within about a year of production. 10 Be from natural archives therefore provides information on past solar activity, and because these archives also contain climate information, solar activity and climate can be linked. One remaining question is to what degree 10 Be in natural archives reflects production, and to what extent the local and regional environment overprints the production signal. To explore this, 10 Be was measured at annual resolution over the last 600 years in a Greenland ice core. Measurement potentials for these samples benefited from the development of a new laboratory method of co-precipitating 10 Be with niobium. To diversify geographic location and archive media type, a pioneer study of measuring 10 Be with annual resolution in varved lake sediments from Finland was conducted, with samples from the entire 20th century. Pathways of 10 Be into lake sediments are more complex than into glacial ice, inferring that contemporary atmospheric conditions may not be recorded. Here, it is shown for the first time that tracing the 11-year solar cycle through lake sediment 10 Be variations is possible. Results also show that on an annual basis, 10 Be deposition in ice and sediment archives is affected by local environmental conditions. On a slightly longer timescale, however, diverse 10 Be records exhibit similar trends and a negative correlation with solar activity. Cyclic variability of 10 Be deposition persisted throughout past grand solar minima, when

  1. natural

    Directory of Open Access Journals (Sweden)

    Elías Gómez Macías

    2006-01-01

    Full Text Available Partiendo de óxido de magnesio comercial se preparó una suspensión acuosa, la cual se secó y calcinó para conferirle estabilidad térmica. El material, tanto fresco como usado, se caracterizó mediante DRX, área superficial BET y SEM-EPMA. El catalizador mostró una matriz de MgO tipo periclasa con CaO en la superficie. Las pruebas de actividad catalítica se efectuaron en lecho fijo empacado con partículas obtenidas mediante prensado, trituración y clasificación del material. El flujo de reactivos consistió en mezclas gas natural-aire por debajo del límite inferior de inflamabilidad. Para diferentes flujos y temperaturas de entrada de la mezcla reactiva, se midieron las concentraciones de CH4, CO2 y CO en los gases de combustión con un analizador de gases tipo infrarrojo no dispersivo (NDIR. Para alcanzar conversión total de metano se requirió aumentar la temperatura de entrada al lecho a medida que se incrementó el flujo de gases reaccionantes. Los resultados obtenidos permiten desarrollar un sistema de combustión catalítica de bajo costo con un material térmicamente estable, que promueva la alta eficiencia en la combustión de gas natural y elimine los problemas de estabilidad, seguridad y de impacto ambiental negativo inherentes a los procesos de combustión térmica convencional.

  2. Influence of natural organic matter fouling and osmotic backwash on pressure retarded osmosis energy production from natural salinity gradients.

    Science.gov (United States)

    Yip, Ngai Yin; Elimelech, Menachem

    2013-01-01

    Pressure retarded osmosis (PRO) has the potential to produce clean, renewable energy from natural salinity gradients. However, membrane fouling can lead to diminished water flux productivity, thus reducing the extractable energy. This study investigates organic fouling and osmotic backwash cleaning in PRO and the resulting impact on projected power generation. Fabricated thin-film composite membranes were fouled with model river water containing natural organic matter. The water permeation carried foulants from the feed river water into the membrane porous support layer and caused severe water flux decline of ∼46%. Analysis of the water flux behavior revealed three phases in membrane support layer fouling. Initial foulants of the first fouling phase quickly adsorbed at the active-support layer interface and caused a significantly greater increase in hydraulic resistance than the subsequent second and third phase foulants. The water permeability of the fouled membranes was lowered by ∼39%, causing ∼26% decrease in projected power density. A brief, chemical-free osmotic backwash was demonstrated to be effective in removing foulants from the porous support layer, achieving ∼44% recovery in projected power density. The substantial performance recovery after cleaning was attributed to the partial restoration of the membrane water permeability. This study shows that membrane fouling detrimentally impacts energy production, and highlights the potential strategies to mitigate fouling in PRO power generation with natural salinity gradients.

  3. Behaviour of palladium(II), platinum(IV), and rhodium(III) in artificial and natural waters: Influence of reactor surface and geochemistry on metal recovery

    Energy Technology Data Exchange (ETDEWEB)

    Cobelo-Garcia, Antonio [School of Earth, Ocean and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom)]. E-mail: antonio.cobelo-garcia@plymouth.ac.uk; Turner, Andrew [School of Earth, Ocean and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom); Millward, Geoffrey E. [School of Earth, Ocean and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom); Couceiro, Fay [School of Earth, Ocean and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom)

    2007-03-07

    The recovery of dissolved platinum group elements (PGE: Pd(II), Pt(IV) and Rh(III)) added to Milli-Q[reg] water, artificial freshwater and seawater and filtered natural waters has been studied, as a function of pH and PGE concentration, in containers of varying synthetic composition. The least adsorptive and/or precipitative loss was obtained for borosilicate glass under most of the conditions employed, whereas the greatest loss was obtained for low-density polyethylene. Of the polymeric materials tested, the adsorptive and/or precipitative loss of PGE was lowest for fluorinated ethylene propylene (Teflon[reg]). The loss of Pd(II) in freshwater was significant due to its affinity for surface adsorption and its relatively low solubility. The presence of natural dissolved organic matter increases the recovery of Pd(II) but enhances the loss of Pt(IV). The loss of Rh(III) in seawater was significant and was mainly due to precipitation, whereas Pd(II) recovery was enhanced, compared to freshwater, because of its complexation with chloride. The results have important implications regarding protocols employed for sample preservation and controlled laboratory experiments used in the study of the speciation and biogeochemical behaviour of PGE.

  4. Influence of extensive compressed natural gas (CNG) usage on air quality

    Science.gov (United States)

    Suthawaree, Jeeranut; Sikder, Helena Akhter; Jones, Charlotte Emily; Kato, Shungo; Kunimi, Hitoshi; Mohammed Hamidul Kabir, Abu Naser; Kajii, Yoshizumi

    2012-07-01

    Compressed Natural Gas (CNG) is an inexpensive, indigenous energy resource which currently accounts for the majority of automobile and domestic energy consumption in Bangladesh. This extensive CNG usage, particularly within the capital city, Dhaka, heavily influences the atmospheric composition (and hence air quality), yet to date measurements of trace gases in regions dominated by CNG emissions are relatively limited. Here we report continuous observations of the atmospherically important trace gases O3, CO, SO2, NOx and volatile organic compounds (VOC), in ambient air in Dhaka City, Bangladesh, during May 2011. The average mixing ratios of O3, CO, SO2, and NOx for the measurement period were 18.9, 520.9, 7.6 and 21.5 ppbv, respectively. The ratios of CO to NO reveal that emissions from gasoline and CNG-fuelled vehicles were dominant during the daytime (slope of ˜26), while in contrast, owing to restrictions imposed on diesel fuelled vehicles entering Dhaka City, emissions from these vehicles only became significant during the night (slope of ˜10). The total VOC mixing ratio in Dhaka was ˜5-10 times higher than the levels reported in more developed Asian cities such as Tokyo and Bangkok, which consequently gives rise to a higher ozone formation potential (OFP). However, the most abundant VOC in Dhaka were the relatively long-lived ethane and propane (with mean mixing ratios of ˜115 and ˜30 ppbv, respectively), and as a consequence, the ozone formation potential per ppb carbon (ppbC) was lower in Dhaka than in Tokyo and Bangkok. Thus the atmospheric composition of air influenced by extensive CNG combustion may be characterized by high VOC mixing ratios, yet mixing ratios of the photochemical pollutant ozone do not drastically exceed the levels typical of Asian cities with considerably lower VOC levels.

  5. The Oral Microbiome of Denture Wearers Is Influenced by Levels of Natural Dentition

    Science.gov (United States)

    O’Donnell, Lindsay E.; Robertson, Douglas; Nile, Christopher J.; Cross, Laura J.; Riggio, Marcello; Sherriff, Andrea; Bradshaw, David; Lambert, Margaret; Malcolm, Jennifer; Buijs, Mark J.; Zaura, Egija; Crielaard, Wim; Brandt, Bernd W.; Ramage, Gordon

    2015-01-01

    Objectives The composition of dental plaque has been well defined, whereas currently there is limited understanding of the composition of denture plaque and how it directly influences denture related stomatitis (DS). The aims of this study were to compare the microbiomes of denture wearers, and to understand the implications of these towards inter-kingdom and host-pathogen interactions within the oral cavity. Methods Swab samples were obtained from 123 participants wearing either a complete or partial denture; the bacterial composition of each sample was determined using bar-coded illumina MiSeq sequencing of the bacterial hypervariable V4 region of 16S rDNA. Sequencing data processing was undertaken using QIIME, clustered in Operational Taxonomic Units (OTUs) and assigned to taxonomy. The dentures were sonicated to remove the microbial flora residing on the prosthesis, sonicate was then cultured using diagnostic colorex Candida media. Samples of unstimulated saliva were obtained and antimicrobial peptides (AMP) levels were measured by ELISA. Results We have shown that dental and denture plaques are significantly distinct both in composition and diversity and that the oral microbiome composition of a denture wearer is variable and is influenced by the location within the mouth. Dentures and mucosa were predominantly made up of Bacilli and Actinobacteria. Moreover, the presence of natural teeth has a significant impact on the overall microbial composition, when compared to the fully edentulous. Furthermore, increasing levels of Candida spp. positively correlate with Lactobacillus spp. AMPs were quantified, though showed no specific correlations. Conclusions This is the first study to provide a detailed understanding of the oral microbiome of denture wearers and has provided evidence that DS development is more complex than simply a candidal infection. Both fungal and bacterial kingdoms clearly play a role in defining the progression of DS, though we were unable to

  6. Major factors influencing the generation of natural gas hydrate in porous media

    Directory of Open Access Journals (Sweden)

    V.N. Khlebnikov

    2017-11-01

    Full Text Available Current researches related to natural gas hydrate mainly focus on its physical and chemical properties, as well as the approaches to the production (decomposition of hydrate. Physical modeling of the flow process in hydrate deposits is critical to the study on the exploitation or decomposition of hydrate. However, investigation of the dynamic hydrate process by virtue of porous media like sand-packed tubes which are widely used in petroleum production research is rarely reported in literature. In this paper, physical simulation of methane hydrate generation process was conducted using river sand-packed tubes in the core displacement apparatus. During the simulation, the influences of parameters such as reservoir temperature, methane pressure and reservoir model properties on the process of hydrate generation were investigated. The following results are revealed. First, the use of ice-melted water as the immobile water in the reservoir model can significantly enhance the rate of methane hydrate generation. Second, the process driving force in porous media (i.e., extents to which the experimental pressure or temperature deviating those corresponding to the hydrate phase equilibrium plays a key role in the generation of methane hydrate. Third, the induction period of methane hydrate generation almost does not change with temperature or pressure when the methane pressure is above 1.4 folds of the hydrate phase equilibrium pressure or the laboratory temperature is lower than the phase equilibrium temperature by 3 °C or more. Fourth, the parameters such as permeability, water saturation and wettability don't have much influence on the generation of methane hydrate.

  7. Epiphytic lichen diversity in central European oak forests: Assessment of the effects of natural environmental factors and human influences

    International Nuclear Information System (INIS)

    Svoboda, David; Peksa, Ondrej; Vesela, Jana

    2010-01-01

    We investigated lichen diversity in temperate oak forests using standardized protocols. Forty-eight sites were sampled in the Czech Republic, Slovakia and Hungary. The effects of natural environmental predictors and human influences on lichen diversity (lichen diversity value, species richness) were analysed by means of correlation tests. We found that lichen diversity responded differently to environmental predictors between two regions with different human impact. In the industrial region, air pollution was the strongest factor. In the agricultural to highly forested regions, lichen diversity was strongly influenced by forest age and forest fragmentation. We found that several natural factors can in some cases obscure the effect of human influences. Thus, factors of naturality gradient must be considered (both statistically and interpretively) when studying human impact on lichen diversity. - We detected the different responses of lichens to ecological predictors in polluted and unpolluted areas.

  8. The Scope of Our Affective Influences: When and How Naturally Occurring Positive, Negative, and Neutral Affects Alter Judgment.

    Science.gov (United States)

    Gasper, Karen; Danube, Cinnamon L

    2016-03-01

    To determine how naturally arising affect alters judgment, we examined whether (a) affective states exert a specific, rather than a general, influence on valenced-specific judgments; (b) neutral affect is associated with increased neutral judgments, independent of positive, negative, and ambivalent affects, and whether neutral judgments are associated with behavioral disengagement; and (c) the informational value of naturally arising states may be difficult to alter via salience and relevance manipulations. The results support several conclusions: (a) Affective states exerted a judgment-specific effect-positive affect was most strongly associated with positive judgments, negative affect with negative judgments, and neutral affect with neutral judgments. (b) Neutral affect influenced judgments, taking into account positive, negative, and ambivalent affects; and neutral judgments predicted behavioral disengagement. (c) With the exception of negative affect, naturally arising affective states typically influenced judgments regardless of their salience and relevance. © 2016 by the Society for Personality and Social Psychology, Inc.

  9. Substrate use of Pseudovibrio sp. growing in ultra-oligotrophic seawater.

    Directory of Open Access Journals (Sweden)

    Anne Schwedt

    Full Text Available Marine planktonic bacteria often live in habitats with extremely low concentrations of dissolved organic matter (DOM. To study the use of trace amounts of DOM by the facultatively oligotrophic Pseudovibrio sp. FO-BEG1, we investigated the composition of artificial and natural seawater before and after growth. We determined the concentrations of dissolved organic carbon (DOC, total dissolved nitrogen (TDN, free and hydrolysable amino acids, and the molecular composition of DOM by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR-MS. The DOC concentration of the artificial seawater we used for cultivation was 4.4 μmol C L(-1, which was eight times lower compared to the natural oligotrophic seawater we used for parallel experiments (36 μmol C L(-1. During the three-week duration of the experiment, cell numbers increased from 40 cells mL(-1 to 2x10(4 cells mL(-1 in artificial and to 3x10(5 cells mL(-1 in natural seawater. No nitrogen fixation and minor CO2 fixation (< 1% of cellular carbon was observed. Our data show that in both media, amino acids were not the main substrate for growth. Instead, FT-ICR-MS analysis revealed usage of a variety of different dissolved organic molecules, belonging to a wide range of chemical compound groups, also containing nitrogen. The present study shows that marine heterotrophic bacteria are able to proliferate with even lower DOC concentrations than available in natural ultra-oligotrophic seawater, using unexpected organic compounds to fuel their energy, carbon and nitrogen requirements.

  10. Potential Effects of Desalinated Seawater on Arteriosclerosis in Rats.

    Science.gov (United States)

    Duan, Lian; Zhang, Li Xia; Zhang, Shao Ping; Kong, Jian; Zhi, Hong; Zhang, Ming; Lu, Kai; Zhang, Hong Wei

    2017-10-01

    To evaluate the potential risk of arteriosclerosis caused by desalinated seawater, Wistar rats were provided desalinated seawater over a 1-year period, and blood samples were collected at 0, 90, 180, and 360 days. Blood calcium, magnesium, and arteriosclerosis-related indicators were investigated. Female rats treated with desalinated seawater for 180 days showed lower magnesium levels than the control rats (P seawater for 360 days (P seawater, and no increase in risk of arteriosclerosis was observed. Copyright © 2017 The Editorial Board of Biomedical and Environmental Sciences. Published by China CDC. All rights reserved.

  11. Natural regeneration on seismic lines influences movement behaviour of wolves and grizzly bears.

    Science.gov (United States)

    Finnegan, Laura; Pigeon, Karine E; Cranston, Jerome; Hebblewhite, Mark; Musiani, Marco; Neufeld, Lalenia; Schmiegelow, Fiona; Duval, Julie; Stenhouse, Gordon B

    2018-01-01

    Across the boreal forest of Canada, habitat disturbance is the ultimate cause of caribou (Rangifer tarandus caribou) declines. Habitat restoration is a focus of caribou recovery efforts, with a goal to finding ways to reduce predator use of disturbances, and caribou-predator encounters. One of the most pervasive disturbances within caribou ranges in Alberta, Canada are seismic lines cleared for energy exploration. Seismic lines facilitate predator movement, and although vegetation on some seismic lines is regenerating, it remains unknown whether vegetation regrowth is sufficient to alter predator response. We used Light Detection and Ranging (LiDAR) data, and GPS locations, to understand how vegetation and other attributes of seismic lines influence movements of two predators, wolves (Canis lupus) and grizzly bears (Ursus arctos). During winter, wolves moved towards seismic lines regardless of vegetation height, while during spring wolves moved towards seismic lines with higher vegetation. During summer, wolves moved towards seismic lines with lower vegetation and also moved faster near seismic lines with vegetation grizzly bears during spring and summer, but there was no relationship between vegetation height and grizzly bear movement rates. These results suggest that wolves use seismic lines for travel during summer, but during winter wolf movements relative to seismic lines could be influenced by factors additional to movement efficiency; potentially enhanced access to areas frequented by ungulate prey. Grizzly bears may be using seismic lines for movement, but could also be using seismic lines as a source of vegetative food or ungulate prey. To reduce wolf movement rate, restoration could focus on seismic lines with vegetation <1 m in height. However our results revealed that seismic lines continue to influence wolf movement behaviour decades after they were built, and even at later stages of regeneration. Therefore it remains unknown at what stage of natural

  12. A numerical study on the influence of slope and curvature on smoke flow in special section tunnel with natural ventilation

    Science.gov (United States)

    Wang, Wenzhou; Zhou, Xianping; Liu, Zhigang; Liu, Ya; Liu, Wanfu; Hong, Li

    2017-09-01

    In this study, a special section tunnel model was established by using FDS (Fire Dynamics Simulator). The influences of lope and curvature on smoke flow under natural ventilation have been studied. The results showed that under the condition of natural ventilation, the slope has some influences on the smoke flow in special section tunnel. The smoke spreading speed is accelerated along the upstream direction and decrease along the downstream direction due to buoyancy effect of slope. The steeper the tunnel, the more obvious the buoyancy effect. The curvature has little effect on the flow of flue gas.

  13. Influence of Uranium on Bacterial Communities: A Comparison of Natural Uranium-Rich Soils with Controls

    Science.gov (United States)

    Mondani, Laure; Benzerara, Karim; Carrière, Marie; Christen, Richard; Mamindy-Pajany, Yannick; Février, Laureline; Marmier, Nicolas; Achouak, Wafa; Nardoux, Pascal; Berthomieu, Catherine; Chapon, Virginie

    2011-01-01

    This study investigated the influence of uranium on the indigenous bacterial community structure in natural soils with high uranium content. Radioactive soil samples exhibiting 0.26% - 25.5% U in mass were analyzed and compared with nearby control soils containing trace uranium. EXAFS and XRD analyses of soils revealed the presence of U(VI) and uranium-phosphate mineral phases, identified as sabugalite and meta-autunite. A comparative analysis of bacterial community fingerprints using denaturing gradient gel electrophoresis (DGGE) revealed the presence of a complex population in both control and uranium-rich samples. However, bacterial communities inhabiting uraniferous soils exhibited specific fingerprints that were remarkably stable over time, in contrast to populations from nearby control samples. Representatives of Acidobacteria, Proteobacteria, and seven others phyla were detected in DGGE bands specific to uraniferous samples. In particular, sequences related to iron-reducing bacteria such as Geobacter and Geothrix were identified concomitantly with iron-oxidizing species such as Gallionella and Sideroxydans. All together, our results demonstrate that uranium exerts a permanent high pressure on soil bacterial communities and suggest the existence of a uranium redox cycle mediated by bacteria in the soil. PMID:21998695

  14. The influence of global warming on natural disasters and their public health outcomes.

    Science.gov (United States)

    Diaz, James H

    2007-01-01

    With a documented increase in average global surface temperatures of 0.6 degrees C since 1975, Earth now appears to be warming due to a variety of climatic effects, most notably the cascading effects of greenhouse gas emissions resulting from human activities. There remains, however, no universal agreement on how rapidly, regionally, or asymmetrically the planet will warm or on the true impact of global warming on natural disasters and public health outcomes. Most reports to date of the public health impact of global warming have been anecdotal and retrospective in design and have focused on the increase in heat-stroke deaths following heat waves and on outbreaks of airborne and arthropod-borne diseases following tropical rains and flooding that resulted from fluctuations in ocean temperatures. The effects of global warming on rainfall and drought, tropical cyclone and tsunami activity, and tectonic and volcanic activity will have far-reaching public health effects not only on environmentally associated disease outbreaks but also on global food supplies and population movements. As a result of these and other recognized associations between climate change and public health consequences, many of which have been confounded by deficiencies in public health infrastructure and scientific debates over whether climate changes are spawned by atmospheric cycles or anthropogenic influences, the active responses to progressive climate change must include combinations of economic, environmental, legal, regulatory, and, most importantly, public health measures.

  15. Influence of natural organic matter on the speciation of radionuclides in a geochemistry context

    International Nuclear Information System (INIS)

    Marang, L.

    2007-09-01

    The principal aim of this work is the study of the influence of natural organic matter, in particularly humic substances (HS), on the speciation of radionuclides (RN). The studied radionuclides are cobalt (II), europium (III) and uranium (VI). It has been shown that mobility and bioavailability of a metal are related to its speciation. The NICA-Donnan model describes metal ion binding to NOM: it accounts for NOM chemical heterogeneity, competition during binding and ionic strength effects. However the model has been calibrated with a limited number of experimental data for the RN. Indeed there is only a few speciation technique available for the study of the interactions RN-HS. Within the framework of this study, we have developed and optimised speciation technique (Flux Donnan Membrane Technique and the use of an un-solubilized humic acid) in order to acquire new experimental data, we have also studied the effect of the competition on RN speciation and finally we have tested the model capacity to predict the RN behavior in laboratory or in situ. (author)

  16. Influence of natural organic matter on the speciation of radionuclides in a geochemistry context

    International Nuclear Information System (INIS)

    Marang, L.

    2007-09-01

    The principal aim of this work is the study of the influence of natural organic matter, in particularly humic substances (HS), on the speciation of radionuclides (RN). The studied radionuclides are cobalt (II), europium (III) and uranium (VI). It has been shown that mobility and bioavailability of a metal are related to its speciation. The NICA-Donnan model describes metal ion binding to NOM: it accounts for NOM chemical heterogeneity, competition during binding and ionic strength effects. However the model has been calibrated with a limited number of experimental data for the RN. Indeed there is only a few speciation techniques available for the study of the interactions RN-HS. Within the framework of this study, we have developed and optimised speciation technique (Flux Donnan Membrane Technique and the use of an insolubilized humic acid) in order to acquire new experimental data, we have also studied the effect of the competition on RN speciation and finally we have tested the model capacity to predict the RN behavior in laboratory or in situ. (author)

  17. INFLUENCE OF THE NATURAL ILLUMINATION LEVEL ON THE INDOOR GROWTH AND DEVELOPMENT OF PETUNIA HYBRIDA

    Directory of Open Access Journals (Sweden)

    B. Lixandru

    2004-01-01

    Full Text Available In a room with a natural illumination index (NII of 4.79, for 70 days, the influence of three illumination levels on the growth and development process of petunias from the Petunia hybrida species was studied. After rising, plants were placed in three zones of the room with different illumination levels: zone A (683 lx – situated on the window’s sill, zone B (113 lx – situated on the floor, at the base of the parapet, and zone C (376 lx – situated in the center of the room, on a table, at 80 cm from the floor. After two weeks from the pricking out, plants were transplanted in glass pots of 200 ml. At 2, 15, 30, 50 and 70 days the maximum length of the stem, branching level and leaf number were determined. At the end of the experiment and 10 days of room temperature drying, root, stem, leaf and flower biomass quantity was determined. Our results evidence the negative effect of the low illumination level (113 lx and 376 lx on the growth and development process of petunias from the Petunia hybrida species. Being a light and warmth loving plant, P. hybrida may be grown only at well-illuminated windows, with a level of minimum 1000 lx.

  18. Shielding effect of building to natural radiation and its influence to population dose evaluation

    International Nuclear Information System (INIS)

    Nakamura, Takashi; Itoh, Kazuo; Yoshimura, Toshiaki.

    1980-01-01

    This work investigated the shielding effect of the building which is indispensable for the accurate evaluation of the population dose of external exposure from natural radiation. At first, the attenuation coefficients of various building materials were measured and found to agree with the calculated values within 10% errors. The shielding factors of these materials were calculated from the calculated attenuation coefficients and buildup factors. The shielding factors of the wall, window, roof and floor were calculated separately by settling the model houses and combining the shielding factors of the building materials used, and then the shielding factor of the whole building was obtained by use of the opening fraction of the wall and the fractions of the wall, roof and floor areas to the total floor area. The influence of the shielding effect of the building is well represented by the occupancy factor which is the ratio of the group doses including that shielding effect to those excluding it. The occupancy factor lies between 0.9 and 1.0 for four specified districts, Tokyo, Osaka, Ibaraki and Nagano. (author)

  19. Understanding Marine Biocorrosion: Experiments with Artificial and Natural Seawater

    Science.gov (United States)

    2015-11-04

    ester biodiesel . Hamilton ( 2003 ) reviewed the data of others and offered a model for microbiologically infl uenced corrosion. He concluded that...investigators have proposed an alternative electron transport mechanism for SRB infl uenced corrosion of ferrous alloys. Venzlaff et al . ( 2013...However, Lee et al . ( 2010a; 2012 ; 2014 ) subsequently demonstrated that addition of readily biodegradable fatty acid methyl ester biodiesel to

  20. New insight into the ternary complexes of uranyl carbonate in seawater.

    Science.gov (United States)

    Beccia, M R; Matara-Aho, M; Reeves, B; Roques, J; Solari, P L; Monfort, M; Moulin, C; Den Auwer, C

    2017-11-01

    Uranium is naturally present in seawater at trace levels and may in some cases be present at higher concentrations, due to anthropogenic nuclear activities. Understanding uranium speciation in seawater is thus essential for predicting and controlling its behavior in this specific environmental compartment and consequently, its possible impact on living organisms. The carbonato calcic complex Ca 2 UO 2 (CO 3 ) 3 was previously identified as the main uranium species in natural seawater, together with CaUO 2 (CO 3 ) 3 2- . In this work, we further investigate the role of the alkaline earth cation in the structure of the ternary uranyl-carbonate complexes. For this purpose, artificial seawater, free of Mg 2+ and Ca 2+ , using Sr 2+ as a spectroscopic probe was prepared. Combining TRLIF and EXAFS spectroscopy, together with DFT and theoretical thermodynamic calculations, evidence for the presence of Sr alkaline earth counter ion in the complex structure can be asserted. Furthermore, data suggest that when Ca 2+ is replaced by Sr 2+ , SrUO 2 (CO 3 ) 3 2- is the main complex in solution and it occurs with the presence of at least one monodentate carbonate in the uranyl coordination sphere. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Towards a quality-controlled and accessible Pitzer model for seawater and related systems

    Directory of Open Access Journals (Sweden)

    David Turner

    2016-09-01

    Full Text Available We elaborate the need for a quality-controlled chemical speciation model for seawater and related natural waters, work which forms the major focus of SCOR Working Group 145. Model development is based on Pitzer equations for the seawater electrolyte and trace components. These equations can be used to calculate activities of dissolved ions and molecules and, in combination with thermodynamic equilibrium constants, chemical speciation. The major tasks to be addressed are ensuring internal consistency of the Pitzer model parameters (expressing the interactions between pairs and triplets of species, which ultimately determines the calculated activities, assessing uncertainties, and identifying important data gaps that should be addressed by new measurements. It is recognised that natural organic matter plays an important role in many aquatic ecosystems, and options for including this material in a Pitzer-based model are discussed. The process of model development begins with the core components which include the seawater electrolyte and the weak acids controlling pH. This core model can then be expanded by incorporating additional chemical components, changing the standard seawater composition and/or broadening the range of temperature and pressure, without compromising its validity. Seven important areas of application are identified: open ocean acidification; micro-nutrient biogeochemistry and geochemical tracers; micro-nutrient behaviour in laboratory studies; water quality in coastal and estuarine waters; cycling of nutrients and trace metals in pore waters; chemical equilibria in hydrothermal systems; brines and salt lakes.

  2. Recovery of uranium from sea-water

    International Nuclear Information System (INIS)

    Llewelyn, G.I.W.

    1976-01-01

    The possibility of extraction of uranium from sea-water on a sufficiently large scale to contribute significantly to national UK requirements is placed in perspective. It seems unlikely that there are sites around the UK coast where this could be achieved, and insufficient work has been done to be confident that sites exist anywhere to enable uranium extraction to be carried out on a large scale. Process techniques have been developed on a small scale, but extensive further research work would be necessary to reduce appreciably the present uncertainties. It would be unwise to expect uranium from sea-water to contribute significant amounts to the world's uranium demand for thermal reactors on an acceptable timescale. (author)

  3. Radiochemical determination of cesium-137 in seawater

    International Nuclear Information System (INIS)

    Cunha, I.I.L.; Munita, C.S.; Paiva, R.P.

    1990-01-01

    Seawater samples were collected from the Atlantic Ocean, in the vicinity of Ubatuba (Sao Paulo State - Brazil), acidified to pH 1 and stored in polyethylene containers. Cesium was precipitated with ammonium phospho molybdate (AMP), synthesized in our laboratory. The elements potassium and rubidium present in the seawater are also coprecipitated by AMP and adequate decontamination of the cesium is made by preparing a column by mixing Cs-137 AMP precipitate and asbestos. The interfering elements were eluted with 1.0 M ammonium nitrate solution whereas cesium was eluted with 1.0 M sodium hydroxide solution. Cesium was reprecipitated by acidifying the solution with concentrated hydrochloric acid. The overall chemical yield of cesium was of 75%. (author)

  4. Process for enriching uranium from seawater

    International Nuclear Information System (INIS)

    Heitkamp, D.; Inden, P.

    1982-01-01

    In selective elutriation of uranium deposited on titanium oxide hydrate by carbonate solution, only uranium should be dissolved from the absorption material forming carbonate compounds, without the deposited ballast ions, above all of magnesium, calcium and sodium being elutriated. The uranium elutriation according to the invention is therefore carried out in the presence of these ballast ions in the same concentrations as those in seawater. The carbonate concentration can only be raised as far as the solubility product of the basic magnesium carbonate permits, so that magnesium remains in the solution, as well as carbonate, in the concentration present in seawater. One must accept the absence of calcium ions in the elutriation solution, as their solubility product with carbonate is considerably less than that for magnesium. (orig./PW) [de

  5. Surfactant induced complex formation and their effects on the interfacial properties of seawater.

    Science.gov (United States)

    Guzmán, Eduardo; Santini, Eva; Benedetti, Alessandro; Ravera, Francesca; Ferrari, Michele; Liggieri, Libero

    2014-11-01

    The effect of a cationic surfactant, hexadecyltrimethylammonium bromide (CTAB), on the interfacial properties of seawater has been studied by dynamic and equilibrium surface tension and by dilational rheology essays. Important modifications of the surface tension and dilational rheology response have been observed already at the very low CTAB concentrations, where the effects due to the high ionic strength are negligible. The comparison with the effects of CTAB in different seawater models, or in natural seawater fractions, points out the establishment of strong interactions between the surfactant molecules and the lipophilic fraction of organic material dispersed/dissolved in seawater, affecting the interfacial activity of the molecules. Considering the biochemical richness of seawater, these results can be explained assuming interaction mechanisms and adsorption schemes similar to those speculated for protein and other macromolecules in the presence of surfactants, which in fact show similar features. Thus already at the low concentrations the surfactant molecules form highly surface-active complexes with part of the organic fraction of seawater. At the larger surfactant concentrations these complexes compete for adsorption with an excess of free CTAB molecules which, according to the thermodynamic conditions, are most favoured to occupy the liquid interface. The results of this study underline the important role of the sea organic content in enhancing the surface-activity of surfactants, which is relevant for a deeper understand of the direct and indirect effects of these types of pollutants on the physico-chemical environment in the sea coastal areas and develop mitigation strategies. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Design Criteria, Operating Conditions, and Nickel-Iron Hydroxide Catalyst Materials for Selective Seawater Electrolysis.

    Science.gov (United States)

    Dionigi, Fabio; Reier, Tobias; Pawolek, Zarina; Gliech, Manuel; Strasser, Peter

    2016-05-10

    Seawater is an abundant water resource on our planet and its direct electrolysis has the advantage that it would not compete with activities demanding fresh water. Oxygen selectivity is challenging when performing seawater electrolysis owing to competing chloride oxidation reactions. In this work we propose a design criterion based on thermodynamic and kinetic considerations that identifies alkaline conditions as preferable to obtain high selectivity for the oxygen evolution reaction. The criterion states that catalysts sustaining the desired operating current with an overpotential seawater-mimicking electrolyte. The catalyst was synthesized by a solvothermal method and the activity, surface redox chemistry, and stability were tested electrochemically in alkaline and near-neutral conditions (borate buffer at pH 9.2) and under both fresh seawater conditions. The Tafel slope at low current densities is not influenced by pH or presence of chloride. On the other hand, the addition of chloride ions has an influence in the temporal evolution of the nickel reduction peak and on both the activity and stability at high current densities at pH 9.2. Faradaic efficiency close to 100 % under the operating conditions predicted by our design criteria was proven using in situ electrochemical mass spectrometry. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Hydrogen evolution in enzymatic photoelectrochemical cell using modified seawater electrolytes produced by membrane desalination process

    Energy Technology Data Exchange (ETDEWEB)

    Joo, Hyunku; Yoon, Jaekyung [Hydrogen Energy Research Center, New and Renewable Energy Research Division, Korea Institute of Energy Research, 71-2 Jang-dong, Yuseong-gu, Daejeon 305-343 (Korea); Bae, Sanghyun [Department of Environmental Engineering, Yonsei University, 234 Maeji-ri, Hungub-myun, Wonju, Gangwon-do 220-710 (Korea); Kim, Chunghwan; Kim, Suhan [Korea Institute of Water and Environment, K-Water, 462-1 Jeonmin-dong, Yuseong-gu, Daejeon 305-730 (Korea)

    2009-09-15

    In the near future, potential water shortages are expected to occur all over the world and this problem will have a significant influence on the availability of water for water-splitting processes, such as photocatalysis and electrolysis, as well as for drinking water. For this reason, it has been suggested that seawater could be used as an alternative for the various water industries including hydrogen production. Seawater contains a large amount of dissolved ion components, thus allowing it to be used as an electrolyte in photoelectrochemical (PEC) systems for producing hydrogen. Especially, the concentrate (retentate) stream shows higher salinity than the seawater fed to the membrane desalination process, because purified water (fresh water) is produced as the permeate stream and the waste brine is more concentrated than the original seawater. In this study, we investigated the hydrogen evolution rate in a photoelectrochemical system, including the preparation and characterization of an anodized tubular TiO{sub 2} electrode (ATTE) as both the photoanode and the cathode with the assistance of an immobilized hydrogenase enzyme and an external bias (solar cell), and the use of various qualities of seawater produced by membrane desalination processes as the electrolyte. The results showed that the rate of hydrogen evolution obtained using the nanofiltration (NF) retentate in the PEC system is ca. 105 {mu}mol/cm{sup 2} h, showing that this is an effective seawater electrolyte for hydrogen production, the optimum amount of enzyme immobilized on the cathode is ca. 3.66 units per geometrical unit area (1 cm x 1 cm), and the optimum external external bias supplied by the solar cell is 2.0 V. (author)

  8. Does natural disaster influence people's risk preference and trust? An experiment from cyclone prone coast of Bangladesh

    DEFF Research Database (Denmark)

    Ahsan, Dewan

    2014-01-01

    Natural catastrophic events may have enormous negative effects on economic growth. People affected by the disaster might be risk averse because of anxiety about the future uncertainty of economic returns. The purpose of this empirical study is to highlight the effect of natural disasters...... (specifically coastal cyclonic storm surges) on individuals' risk preference and level of trust. This study also aims to disentangle risk propensity from trust. It reveals that natural disasters can significantly reduce people's risk-taking attitudes, whereas the catastrophic events have no influence...... on trusting behavior. The study suggests that risk attitudes are significantly negatively correlated with trust....

  9. Uncertainties in Climatological Seawater Density Calculations

    Science.gov (United States)

    Dai, Hao; Zhang, Xining

    2018-03-01

    In most applications, with seawater conductivity, temperature, and pressure data measured in situ by various observation instruments e.g., Conductivity-Temperature-Depth instruments (CTD), the density which has strong ties to ocean dynamics and so on is computed according to equations of state for seawater. This paper, based on density computational formulae in the Thermodynamic Equation of Seawater 2010 (TEOS-10), follows the Guide of the expression of Uncertainty in Measurement (GUM) and assesses the main sources of uncertainties. By virtue of climatological decades-average temperature/Practical Salinity/pressure data sets in the global ocean provided by the National Oceanic and Atmospheric Administration (NOAA), correlation coefficients between uncertainty sources are determined and the combined standard uncertainties uc>(ρ>) in seawater density calculations are evaluated. For grid points in the world ocean with 0.25° resolution, the standard deviations of uc>(ρ>) in vertical profiles cover the magnitude order of 10-4 kg m-3. The uc>(ρ>) means in vertical profiles of the Baltic Sea are about 0.028kg m-3 due to the larger scatter of Absolute Salinity anomaly. The distribution of the uc>(ρ>) means in vertical profiles of the world ocean except for the Baltic Sea, which covers the range of >(0.004,0.01>) kg m-3, is related to the correlation coefficient r>(SA,p>) between Absolute Salinity SA and pressure p. The results in the paper are based on sensors' measuring uncertainties of high accuracy CTD. Larger uncertainties in density calculations may arise if connected with lower sensors' specifications. This work may provide valuable uncertainty information required for reliability considerations of ocean circulation and global climate models.

  10. Effect of Greenhouse Gases Dissolved in Seawater.

    Science.gov (United States)

    Matsunaga, Shigeki

    2015-12-30

    A molecular dynamics simulation has been performed on the greenhouse gases carbon dioxide and methane dissolved in a sodium chloride aqueous solution, as a simple model of seawater. A carbon dioxide molecule is also treated as a hydrogen carbonate ion. The structure, coordination number, diffusion coefficient, shear viscosity, specific heat, and thermal conductivity of the solutions have been discussed. The anomalous behaviors of these properties, especially the negative pressure dependence of thermal conductivity, have been observed in the higher-pressure region.

  11. Drinking water in Cuba and seawater desalination

    International Nuclear Information System (INIS)

    Meneses-Ruiz, E.; Turtos-Carbonell, L.M.; Oviedo-Rivero, I.

    2004-01-01

    The lack of drinking water has become a problem at world level because, in many places, supplies are very limited and, in other places, their reserves have been drained. At the present time there are estimated to be around two thousand million people that don't have drinking water for several reasons, such as drought, contamination and the presence of saline waters not suitable for human consumption. Because of the human need for water, they have always taken residence in areas where the supply was guaranteed, sometimes impeding the exploitation of other areas that can be economically very interesting. However, this resource is usually very close and in abundance in the form of seawater but its salinity makes it unusable for many basic requirements. Humanity has been forced, therefore, to take into consideration the possibilities of the economic treatment of seawater. Cuba has regions where the supplies of drinking water are scarce and others where the lack of this resource limits economic exploitation. The present work is approached with regard to the situation of hydro resources in Cuba, it includes: a description of the main hydrographic basins of the country; the contamination levels of the waters and the measures for mitigation; analysis of the supplies and demand for drinking water and its quality; regulatory aspects. The state of seawater desalination in Cuba is also included and the possibility of its realisation using nuclear energy and the advantages that this would bring is evaluated. (author)

  12. 60Co levels in the seawater regions

    International Nuclear Information System (INIS)

    Yoshioka, Mitsuo

    1983-01-01

    In order to assess the contribution from nuclear power facilities to the 60 Co levels in seawater regions, it is essential to grasp the background values of 60 Co. The following matters are described: 60 Co sources and the respective inputs; nuclear test fallout and nuclear power plants; the 60 Co levels in overseas countries; the 60 Co levels in Japan; the 60 Co levels from nuclear power plants in Fukui prefecture. In the seawater regions around Japan, there have been numerous instances of 60 Co detection; several pCi/kg of dry earth in sea bottom earth and about 1 pCi/kg of raw material in marine life can be considered as the background levels due to nuclear test fallout and nuclear-powered submarines. In the seawater regions of Fukui prefecture, the 60 Co levels appreciably exceeded the above background due to the nuclear power plants, which are insignificant concerning the radiation exposure of the local people. (Mori, K.)

  13. Influence of Natural Organic Matter on Attachment Kinetics of Salmonella Typhimurium

    Science.gov (United States)

    Chowdhury, I.; Zorlu, O.; Hill, J. E.; Walker, S. L.

    2011-12-01

    Salmonella enterica serovar Typhimurium is one of the most common and virulent bacterial pathogens, usually found in food and water. This waterborne pathogen has been attributed to causing gastroenteritis and typhoid fever, leading to 16 million cases and over half a million deaths worldwide each year. Natural organic matter (NOM) is ubiquitous in environment and previous work has shown NOM to enhance the stability and transport of bacteria cells; hence NOM will certainly interact with Salmonella and affect its transport in environment. The objective of this study was to investigate the influence of NOM (Suwannee River humic acid standard II, SRHA) on the attachment kinetics of a model Salmonella (Salmonella enterica serovar Typhimurium SA5983) to glass. The transport study was conducted in a parallel plate flow chamber using fluorescent microscope to visualize the bacterial cells, which were tagged with green fluorescent protein (GFP). The solution pH was unadjusted, and the flow rate through parallel plate channel was 0.1 mL/min to simulate groundwater conditions. Parameters varied in this study were NOM presence, ion valence (K+, Ca2+) as well as cell growth phase (mid-exponential and late-exponential growth phases). These parameters were chosen because ion valence may alter the NOM conformation and capacity for bridging, as well growth phase impacts the cellular surface chemistry. Extensive characterization of the bacterial cells was conducted including measurements of electrophoretic mobility, hydrophobicity, acidity, surface charge density and extracellular polymeric substance content. Additionally, electrokintic characterization was conducted for the glass. Preliminary results demonstrated the sensitivity of cell attachment to ionic valence and cell growth phase. Also the addition of NOM reduced the attachment of the Salmonella cells significantly under all of these conditions. Without NOM, attachment efficiencies (α) in KCl were similar at both growth

  14. The influence of natural pozzolana mineralogical composition in the properties of blended cement

    Directory of Open Access Journals (Sweden)

    Gener Rizo, M.

    2002-09-01

    Full Text Available The pozzolana activity is the main property of the active additions but, in order to select them, we have to consider - between other factors- its mineralogical composition with a great influence, not only in the active component, but also in other cement properties. In the present work we have studied 4 different Cuban natural pozzolanes, characterized with the help of X ray diffraction and with thermic and chemical analysis. The pozzolanic activity was also evaluated through a chemical and physicomechanic method. Some cements were prepared with different contents of each one of the pozzolanics, and analysed their physicomechanic and chemical properties. Finally, we found that the pozzolanics mineralogical composition has a great influence in the pozzolanic activity and in the properties of mixed cements. Also we found that it 5 possible to obtain the best resistances in the time and the smaller needs of water when the vitreous phase prevail in the additions.

    La actividad puzolánica es la propiedad fundamental de las adiciones activas, pero para la selección de la misma se debe considerar, entre otros factores, su composición mineralógica, que influye no sólo en los constituyentes activos, sino también en muchas propiedades de los cementos. En el presente trabajo, como material puzolánico se estudiaron 4 puzolanas naturales cubanas, las cuales fueron caracterizadas mediante difracción de Rayos X, análisis térmico y análisis químico; se evaluó, además, la actividad puzolánica mediante un método químico y otro físico-mecánico. Se prepararon cementos con diferentes contenidos de cada una de las puzolanas y se analizaron sus propiedades químicas y físico-mecánicas. Se concluye que la composición mineralógica de las puzolanas influye de forma determinante en la actividad puzolánica y en las propiedades de los cementos mezclados; que los mejores desarrollos de resistencias en el tiempo y los menores requerimientos

  15. Numerical analysis of the performance of a venturi-shaped roof for natural ventilation : influence of building width

    NARCIS (Netherlands)

    Hooff, van T.A.J.; Blocken, B.J.E.; Aanen, L.; Bronsema, B.

    2012-01-01

    A numerical analysis with Computational Fluid Dynamics (CFD) is performed to investigate the influence of building width on the performance of a venturi-shaped roof (called Ventec roof) for natural ventilation. The specific roof configuration is intended to create an underpressure in the narrowest

  16. Natural recovery and leaf water potential after fire influenced by salvage logging and induced drought stress

    Directory of Open Access Journals (Sweden)

    D. Moya

    2013-01-01

    Full Text Available Salvage logging is one of the most common emergency actions in the short-term management after a fire. Several studies have been carried out and some obtained positive results which incite to carry it out but other, found negative effects on seedling establishment and regeneration. In addition, climatic changes will have large impacts on vegetation productivity and resilience since the regional models for south-eastern Spain predicts a rainfall decrease of about 20% and temperature increase of 4.5 ºC. Our aim was to determine how short-term forest management and induced drought affect the ecosystem recovery in Aleppo pine stands naturally recovered after a fire.In summer 2009, a mid-high severity fire burned 968 ha of Aleppo pine (Pinus halepensis Mill. forest in south-eastern Spain. Six months later, a salvage logging was carried out. The Aleppo pine recruitment was negligible. During summer 2010, twelve square plots (2m x 2m were set in the three scenarios: control, salvaged and drought induced. The surface cover and soil water availability for three dominant understory species were recorded in four field campaigns: Spring-2010, Fall-2010, Spring-2011 and Fall-2011.The season, management and the target species showed significant differences in growing and water stress. In general, Esparto grass showed lower water stress, mainly in Fall, a higher increase of total coverage. Both effects were showing their highest values in non-salvaged areas and no drought. Changes in leaf water potential and soil water content after the drought season influence the survival and development of individuals.Our results indicate that soil water content and ecosystem response can be modified by short-term silvicultural treatments. Therefore, management after fire could cause opposite effects to those initially foreseen, since they depend on fire severity, and type of ecosystem management response. So, their application must be evaluated and assessed before

  17. Corrosion fatigue of high strength fastener materials in seawater

    Science.gov (United States)

    Tipton, D. G.

    1983-12-01

    Environmental effects which significantly reduce the fatigue life of metals are discussed. Corrosion fatigue is a major concern in the engineering application of high strength fasteners in marine environments. The corrosion fatigue failure of an AISI 41L4O high strength steel blade to hub attachment bolt at the MOD-OA 200 kW wind turbine generator was investigated. The reduction of fatigue strength of AISI 41L4O in marine environments and to obtain similar corrosion fatigue data for candidate replacement materials was studied. The AISI 4140, PH 13-8Mo stainless steel, alloy 718 and alloy MP-35N were tested in axial fatigue at a frequency of 20 Hz in dry air and natural seawater. The fatigue data are fitted by regression equations to allow determination of fatigue strength for a given number of cycles to failure.

  18. Ontogeny of salinity tolerance and evidence for seawater-entry preparation in juvenile green sturgeon, Acipenser medirostris.

    Science.gov (United States)

    Allen, Peter J; McEnroe, Maryann; Forostyan, Tetyana; Cole, Stephanie; Nicholl, Mary M; Hodge, Brian; Cech, Joseph J

    2011-12-01

    We measured the ontogeny of salinity tolerance and the preparatory hypo-osmoregulatory physiological changes for seawater entry in green sturgeon (Acipenser medirostris), an anadromous species occurring along the Pacific Coast of North America. Salinity tolerance was measured every 2 weeks starting in 40-day post-hatch (dph) juveniles and was repeated until 100% survival at 34‰ was achieved. Fish were subjected to step increases in salinity (5‰ 12 h(-1)) that culminated in a 72-h exposure to a target salinity, and treatment groups (0, 15, 20, 25, 30, 34‰; and abrupt exposure to 34‰) were adjusted as fish developed. After 100% survival was achieved (134 dph), a second experiment tested two sizes of fish for 28-day seawater (33‰) tolerance, and gill and gastrointestinal tract tissues were sampled. Their salinity tolerance increased and plasma osmolality decreased with increasing size and age, and electron microscopy revealed three types of mitochondria-rich cells: one in fresh water and two in seawater. In addition, fish held on a natural photoperiod in fresh water at 19°C showed peaks in cortisol, thyroid hormones and gill and pyloric ceca Na(+), K(+)-ATPase activities at body sizes associated with seawater tolerance. Therefore, salinity tolerance in green sturgeon increases during ontogeny (e.g., as these juveniles may move down estuaries to the ocean) with increases in body size. Also, physiological and morphological changes associated with seawater readiness increased in freshwater-reared juveniles and peaked at their seawater-tolerant ages and body sizes. Their seawater-ready body size also matched that described for swimming performance decreases, presumably associated with downstream movements. Therefore, juvenile green sturgeon develop structures and physiological changes appropriate for seawater entry while growing in fresh water, indicating that hypo-osmoregulatory changes may proceed by multiple routes in sturgeons.

  19. Thermodynamical research of using solar energy for desalination of seawater

    Directory of Open Access Journals (Sweden)

    Arsović Marjan R.

    2015-01-01

    Full Text Available Many regions of the world face the problem of saline water. Water desalination processes, which require significant energy consumption, are a common solution to produce drinking water. This study evaluated the influence of the following process operational parameters on the energy consumption of seawater RO systems: water salinity, permeate recovery ratio, membrane performance and feed water temperature. Optimal operational conditions for the theoretical minimum energy consumption were determined with experiments by varying water qualities and operational parameters. In order to further reduce energy consumption a RO system was integrated with a PV solar system and a pilot PVRO system was built and tested. The results obtained from this study indicated that even though a Solar PV system incurs a huge initial capital investment, it will yield significant benefits in the long run of the RO operational period.

  20. Seawater Polluted with Highly Concentrated Polycyclic Aromatic Hydrocarbons Suppresses Osteoblastic Activity in the Scales of Goldfish, Carassius auratus.

    Science.gov (United States)

    Suzuki, Nobuo; Sato, Masayuki; Nassar, Hossam F; Abdel-Gawad, Fagr Kh; Bassem, Samah M; Yachiguchi, Koji; Tabuchi, Yoshiaki; Endo, Masato; Sekiguchi, Toshio; Urata, Makoto; Hattori, Atsuhiko; Mishima, Hiroyuki; Shimasaki, Youhei; Oshima, Yuji; Hong, Chun-Sang; Makino, Fumiya; Tang, Ning; Toriba, Akira; Hayakawa, Kazuichi

    2016-08-01

    We have developed an original in vitro bioassay using teleost scale, that has osteoclasts, osteoblasts, and bone matrix as each marker: alkaline phosphatase (ALP) for osteoblasts and tartrate-resistant acid phosphatase (TRAP) for osteoclasts. Using this scale in vitro bioassay, we examined the effects of seawater polluted with highly concentrated polycyclic aromatic hydrocarbons (PAHs) and nitro-polycyclic aromatic hydrocarbons (NPAHs) on osteoblastic and osteoclastic activities in the present study. Polluted seawater was collected from two sites (the Alexandria site on the Mediterranean Sea and the Suez Canal site on the Red Sea). Total levels of PAHs in the seawater from the Alexandria and Suez Canal sites were 1364.59 and 992.56 ng/l, respectively. We were able to detect NPAHs in both seawater samples. Total levels of NPAHs were detected in the seawater of the Alexandria site (12.749 ng/l) and the Suez Canal site (3.914 ng/l). Each sample of polluted seawater was added to culture medium at dilution rates of 50, 100, and 500, and incubated with the goldfish scales for 6 hrs. Thereafter, ALP and TRAP activities were measured. ALP activity was significantly suppressed by both polluted seawater samples diluted at least 500 times, but TRAP activity did not change. In addition, mRNA expressions of osteoblastic markers (ALP, osteocalcin, and the receptor activator of the NF-κB ligand) decreased significantly, as did the ALP enzyme activity. In fact, ALP activity decreased on treatment with PAHs and NPAHs. We conclude that seawater polluted with highly concentrated PAHs and NPAHs influences bone metabolism in teleosts.

  1. Monitoring the Impact of Anthropogenic and Natural Influences on the Environment of Mesoamerica

    Science.gov (United States)

    Hardin, D.; Graves, S.; Sever, T.; Irwin, D.

    2005-12-01

    Mesoamerica - composed of the seven Central American countries and the five southernmost states of Mexico - is one of the richest biological regions in the world. The region is home to approximately eight percent of the planet's biodiversity. There are 14 biosphere reserves, eight world heritage sites and 589 protected areas. The human population, of over 45 million people consists of more than 50 ethnic groups. This rich biological and cultural diversity is threatened by human influence and natural disasters. Illegal logging and slash and burn agriculture are major contributors to extensive deforestation. Earthquakes, volcanoes, drought, and severe storms threaten the region. Of particular note is the massive destruction and loss of life resulting from hurricane Mitch in 1998. An international effort is underway to preserve the remaining forested regions, with its biodiversity, and to promote sustained development throughout the region. In 2002 the National Aeronautics and Space Administration (NASA) joined with the World Bank and the United States Agency for International Development (USAID) to work with the Central American Commission for Environment and Development (CCAD), to develop an advanced decision support system for Mesoamerica known as SERVIR. (SERVIR is a Spanish acronym meaning to serve.) The partners are contributing expertise in space-based observation with information management technologies and intimate knowledge of local ecosystems to create a system for use by scientists, educators, and policy makers to monitor and forecast ecological changes, respond to natural disasters, and better understand both natural and human induced effects. NASA/Marshall Space Flight Center and the University of Alabama in Huntsville (UAH) are concentrating on the preparation of data products and Information Technology applications that will integrate information from the entire region into a coherent information system that is easy to access and utilize. Already

  2. Perturbations of modeling and forecast of karachi coastal region seawater

    International Nuclear Information System (INIS)

    Hussain, M.A.; Abbas, S.; Ansari, M.R.K.; Zaffar, A.

    2013-01-01

    Global warming is now a stark reality affecting the humanity in many hazardous ways. Continuous floods in Pakistan in past two years are an eye opener in this regard. A great loss of property, agriculture and life as a result of these floods suggests for an intelligent monitoring of the future projections of climate change and global warming. This is necessary because the harmful impacts of natural hazards can be coped and alleviated with a good planning in advance. This monitoring demands for enhanced forecasting capabilities, use of better analytical techniques and a clear determination and study of the controlling factors. Karachi is a coastal city which is also the industrial hub of Pakistan. Moreover, it is among one of the largest metropolitans of the world. So expectedly is most suitable for the study of high level of complex natural and anthropogenic activities. It is peculiar in the sense that it has two summer seasons, a situation scarcely observable on the globe. Here, summer season seawater temperature fluctuations are studied with the help of Seasonal Autoregressive Integrated Moving Average (SARIMA) models and short- and long-term forecasts are made. Our short-term forecasts determine months for the summer wise temperature extremes. It appears that the months of May, June, July and August are the months of extreme temperature for the first summer and October is the month of extreme temperature for the second summer. The long-term forecasts predict that 2014, 2016, 2018, and 2019 will be the years of warm summers. The analysis appearing here would be useful for coastal-urban planners in emphasizing the impact of seawater extreme temperatures on urban industrial activities, etc. (author)

  3. Separated influence of crude oil prices on regional natural gas import prices

    International Nuclear Information System (INIS)

    Ji, Qiang; Geng, Jiang-Bo; Fan, Ying

    2014-01-01

    This paper analyses the impact of global economic activity and international crude oil prices on natural gas import prices in three major natural gas markets using the panel cointegration model. It also investigates the shock impacts of the volatility and the increase and decrease of oil prices on regional natural gas import prices. The results show that both global economic activity and international crude oil prices have significant long-term positive effects on regional natural gas import prices. The volatility of international crude oil prices has a negative impact on regional natural gas import prices. The shock impact is weak in North America, lags in Europe and is most significant in Asia, which is mainly determined by different regional policies for price formation. In addition, the response of natural gas import prices to increases and decreases in international crude oil prices shows an asymmetrical mechanism, of which the decrease impact is relatively stronger. - Highlights: • Impacts of world economy and oil prices on regional natural gas prices are analysed • North American natural gas prices are mainly affected by world economy • Asian and European natural gas prices are mainly affected by oil prices • The volatility of oil prices has a negative impact on regional natural gas prices • The response of natural gas import prices to oil prices up and down shows asymmetry

  4. Seawater movement in the Japan Sea inferred from 14C measurement in seawater

    International Nuclear Information System (INIS)

    Otosaka, Shigeyoshi; Tanaka, Takayuki; Togawa, Orihiko; Amano, Hikaru; Aramaki, Takafumi

    2008-01-01

    Research Group for Environmental Science, JAEA has carried out oceanographic observations in the Japan Sea since 1997 to clarify the biogeochemical cycle in the Japan Sea. More than 3,000 seawater samples for measurement of radiocarbon were collected during the observations, and radiocarbon in the seawater samples was measured at AMS facility in JAEA Mutsu. In this paper, formation and circulation of water mass in the northern Japan Sea were discussed using analysis of radiocarbon and hydrographic data (e.g. salinity, temperature, nutrients). (author)

  5. Characteristics of Urban Natural Areas Influencing Winter Bird Use in Southern Ontario, Canada

    Science.gov (United States)

    Smith, Paul G. R.

    2007-03-01

    Characteristics of urban natural areas and surrounding landscapes were identified that best explain winter bird use for 28 urban natural areas in southern Ontario, Canada. The research confirms for winter birds the importance of area (size) and natural vegetation, rather than managed, horticultural parkland, within urban natural areas as well as percent urban land use and natural habitat in surrounding landscapes. Alien bird density and percent ground feeding species increased with percent surrounding urban land use. Higher percent forest cover was associated with higher percentages of forest, bark feeding, small (species. Natural area size (ha) was related to higher species richness, lower evenness and higher percentages of insectivorous, forest interior, area-sensitive, upper canopy, bark feeding, and non-resident species. Higher number of habitat types within natural areas and percent natural habitat in surrounding landscapes were also associated with higher species richness. Common, resident bird species dominated small areas (20 ha start to support some area-sensitive species. Areas similar to rural forests had >25% insectivores, >25% forest interior species, >25% small species, and species. Indicator species separated urban natural areas from rural habitats and ordination placed urban natural areas along a gradient between urban development and undisturbed, rural forests. More attention is needed on issues of winter bird conservation in urban landscapes.

  6. Methodological Considerations and Comparisons of Measurement Results for Extracellular Proteolytic Enzyme Activities in Seawater

    Directory of Open Access Journals (Sweden)

    Yumiko Obayashi

    2017-10-01

    Full Text Available Microbial extracellular hydrolytic enzymes that degrade organic matter in aquatic ecosystems play key roles in the biogeochemical carbon cycle. To provide linkages between hydrolytic enzyme activities and genomic or metabolomic studies in aquatic environments, reliable measurements are required for many samples at one time. Extracellular proteases are one of the most important classes of enzymes in aquatic microbial ecosystems, and protease activities in seawater are commonly measured using fluorogenic model substrates. Here, we examined several concerns for measurements of extracellular protease activities (aminopeptidases, and trypsin-type, and chymotrypsin-type activities in seawater. Using a fluorometric microplate reader with low protein binding, 96-well microplates produced reliable enzymatic activity readings, while use of regular polystyrene microplates produced readings that showed significant underestimation, especially for trypsin-type proteases. From the results of kinetic experiments, this underestimation was thought to be attributable to the adsorption of both enzymes and substrates onto the microplate. We also examined solvent type and concentration in the working solution of oligopeptide-analog fluorogenic substrates using dimethyl sulfoxide (DMSO and 2-methoxyethanol (MTXE. The results showed that both 2% (final concentration of solvent in the mixture of seawater sample and substrate working solution DMSO and 2% MTXE provide similarly reliable data for most of the tested substrates, except for some substrates which did not dissolve completely in these assay conditions. Sample containers are also important to maintain the level of enzyme activity in natural seawater samples. In a small polypropylene containers (e.g., standard 50-mL centrifugal tube, protease activities in seawater sample rapidly decreased, and it caused underestimation of natural activities, especially for trypsin-type and chymotrypsin-type proteases. In

  7. A fuzzy multicriteria categorization of the GALDIT method to assess seawater intrusion vulnerability of coastal aquifers.

    Science.gov (United States)

    Kazakis, Nerantzis; Spiliotis, Mike; Voudouris, Konstantinos; Pliakas, Fotios-Konstantinos; Papadopoulos, Basil

    2018-04-15

    Groundwater constitutes the primary source of fresh water for >1.2 billion people living in coastal zones. However, the threat of seawater intrusion is widespread in coastal aquifers mainly due to overexploitation of groundwater. In the present study, a modified fuzzy multicriteria categorization into non-ordered categories method was developed in order to modify the standard GALDIT method and assess seawater intrusion vulnerability in a coastal aquifer of northern Greece. The method is based on six parameters: groundwater occurrence, aquifer hydraulic conductivity, groundwater level, distance from the shore, impact of the existing status of seawater intrusion, and aquifer thickness. Initially, the original method was applied and revealed a zone of high vulnerability running parallel to the coastline and covering an area of 8.6km 2 . The modified GALDIT-F method achieved higher discretization of vulnerability zones which is essential to build a rational management plan to prevent seawater intrusion. The GALDIT-F approach also distinguished an area of the aquifer that is influenced by geothermal fluids. In total, twenty-five categories were produced corresponding to different vulnerability degrees according to the initial method (High, Moderate, Low) as well as the area influenced by geothermal fluids. Finally, a road map was developed in order to adapt management strategies to GALDIT-F categories and prevent and mitigate seawater intrusion. The proposed management strategies of the coastal aquifer include managed aquifer recharge (MAR) implementation, reallocation of existing wells, optimization of pumping rates during the hydrological year, and a detailed monitoring plan. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Conceptual design on uranium recovery plant from seawater

    International Nuclear Information System (INIS)

    Kato, Toshiaki; Okugawa, Katsumi; Sugihara, Yutaka; Matsumura, Tsuyoshi

    1999-01-01

    Uranium containing in seawater is extremely low concentration, which is about 3 mg (3 ppb) per 1 ton of seawater. Recently, a report on development of a more effective collector of uranium in seawater (a radiation graft polymerization product of amidoxime onto polyethylene fiber) was issued by Japan Atomic Energy Research Institute. In this paper, an outline design of a uranium recovery plant from seawater was conducted on a base of the collector. As a result of cost estimation, the collection cost of seawater uranium using this method was much higher than that of uranium mine on land and described in the Red Book for mineral uranium cost. In order to make the seawater uranium cost comparable to the on-land uranium cost, it is necessary to establish comprehensive efforts in future technical development, such as development in absorption property of uranium with the collector, resolution method using less HCl, and so forth. (G.K.)

  9. Influence of natural and anthropogenic factors on the dynamics of CO2 emissions from chernozems soil

    Science.gov (United States)

    Syabruk, Olesia

    2017-04-01

    Twentieth century marked a significant expansion of agricultural production. Soil erosion caused by human activity, conversion of forests and grasslands to cropland, desertification, burning nutrient residues, drainage, excessive cultivation led to intense oxidation of soil carbon to the atmosphere and allocation of additional amounts of CO2. According to the UN Intergovernmental Panel on Climate Change, agriculture is one of the main sources of greenhouse gases emissions to the atmosphere. The thesis reveals main patterns of the impact of natural and anthropogenic factors on CO2 emissions in the chernozems typical and podzolized in a Left-bank Forest-Steppe of Ukraine, seasonal and annual dynamics. New provisions for conducting monitoring CO2 emissions from soil were developed by combining observations in natural and controlled conditions, which allows isolating the impact of hydrological, thermal and trophic factors. During the research, the methods for operational monitoring of emission of carbon losses were improved, using a portable infrared gas analyzer, which allows receiving information directly in the field. It was determined that the volumes of emission losses of carbon chernozems typical and podzolized Left-bank Forest-Steppe of Ukraine during the growing season are 480-910 kg/ha and can vary depending on the soil treatment ±( 4,0 - 6,0) % and fertilizer systems ± (3,8 - 7,1) %. The significant impact of long application of various fertilizer systems and soil treatment on the intensity of carbon dioxide emissions was investigated. It was found that most emission occurs in organic- mineral fertilizers systems with direct seeding. The seasonal dynamics of the potential capacity of the soil to produce CO2 were researched. Under identical conditions of humidity and temperature it has maximum in June and July and the gradual extinction of the autumn. It was determined that the intensity of the CO2 emission from the surface of chernozem fluctuates daily from

  10. The distribution of indoor radon in Transylvania (Romania) - influence of the natural and anthropogenic factors

    Science.gov (United States)

    Cucos Dinu, Alexandra; Baciu, Calin; Dicu, Tiberius; Papp, Botond; Moldovan, Mircea; Bety Burghele, Denissa; Tenter, Ancuta; Szacsvai, Kinga

    2017-04-01

    Exposure to radon in homes and workplaces is now recognized as the most important natural factor in causing lung cancer. Radon activity is usually higher in buildings than in the outside atmosphere, as it may be released from building materials and soil beneath the constructions, and the concentration builds-up indoor, due to the low air renewal rates. Indoor radon levels can vary from one to multiple orders of magnitude over time and space, as it depends on several natural and anthropogenic factors, such us the radon concentration in soil under the construction, the weather conditions, the degree of containment in the areas where individuals are exposed, building materials, outside air, tap water and even city gas, the architecture, equipment (chimney, mechanical ventilation systems, etc.), the environmental parameters of the building (temperature, pressure, etc.), and on the occupants' lifestyle. The study presents the distribution of indoor radon in Transylvania, Romania, together with the measurements of radon in soil and soil water. Indoor radon measurements were performed by using CR-39 track detectors exposed for 3 months on ground-floor level of dwellings, according to the NRPB Measurement Protocol. Radon concentrations in soil and water were measured using the LUK3C device. A complete map was plotted at the date, based on 3300 indoor radon measurements, covering an area of about 42% of the Romanian territory. The indoor radon concentrations ranged from 5 to 3287 Bq m-3, with an updated preliminary arithmetic mean of 179 Bq m-3, and a geometric mean of 122 Bq m-3. In about 11% of the investigated grid cells the indoor radon concentrations exceed the threshold of 300 Bq m-3. The soil gas radon concentration varies from 0.8 to 169 kBq m-3, with a geometric mean of 26 kBq m-3. For water samples, the results show radon concentrations within the range of 0.3 - 352.2 kBq m-3, with a geometric mean of 7.7 Bq L-1. A weak correlation between the three sets of values

  11. Determination of strontium-90 from direct separation of yttrium-90 by solid phase extraction using DGA Resin for seawater monitoring.

    Science.gov (United States)

    Tazoe, Hirofumi; Obata, Hajime; Yamagata, Takeyasu; Karube, Zin'ichi; Nagai, Hisao; Yamada, Masatoshi

    2016-05-15

    It is important for public safety to monitor strontium-90 in aquatic environments in the vicinity of nuclear related facilities. Strontium-90 concentrations in seawater exceeding the background level have been observed in accidents of nuclear facilities. However, the analytical procedure for measuring strontium-90 in seawater is highly demanding. Here we show a simple and high throughput analytical technique for the determination of strontium-90 in seawater samples using a direct yttrium-90 separation. The DGA Resin is used to determine the abundance of strontium-90 by detecting yttrium-90 decay (beta-emission) in secular equilibrium. The DGA Resin can selectively collect yttrium-90 and remove naturally occurring radionuclides such as (40)K, (210)Pb, (214)Bi, (238)U, and (232)Th and anthropogenic radionuclides such as (140)Ba, and (140)La. Through a sample separation procedure, a high chemical yield of yttrium-90 was achieved at 95.5±2.3%. The result of IAEA-443 certified seawater analysis (107.7±3.4 mBq kg(-1)) was in good agreement with the certified value (110±5 mBq kg(-1)). By developed method, we can finish analyzing 8 samples per day after achieving secular equilibrium, which is a reasonably fast throughput in actual seawater monitoring. By processing 3 L of seawater sample and applying a counting time of 20 h, minimum detectable activity can be as low as 1.5 mBq kg(-1), which could be applied to monitoring for the contaminated marine environment. Reproducibility was found to be 3.4% according to 10 independent analyses of natural seawater samples from the vicinity of the Fukushima Daiichi Nuclear Power Plant in September 2013. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Seawater intrusion mapping using electrical resistivity tomography and hydrochemical data. An application in the coastal area of eastern Thermaikos Gulf, Greece.

    Science.gov (United States)

    Kazakis, N; Pavlou, A; Vargemezis, G; Voudouris, K S; Soulios, G; Pliakas, F; Tsokas, G

    2016-02-01

    The aim of this study was to determine the extent and geometrical characteristics of seawater intrusion in the coastal aquifer of the eastern Thermaikos Gulf, Greece. Hydrochemical data and geoelectrical measurements were combined and supplemented to determine the hydrochemical regime of the study site in regard to seawater phenomena. Chemical analysis of groundwater was performed in 126 boreholes and fifteen electrical resistivity tomographies (ERT) were measured, whereas in two sites the ERT measurements were repeated following the wet season. The Cl(-) concentrations recorded reached 2240 mg/L indicating seawater intrusion which was also verified by ionic ratios. The ionic ratios were overlapped and a seawater intrusion map (SWIM) was produced. A significant part of the coastal aquifer (up to 150 km(2)) is influenced by seawater intrusion. The areas with the most intensive salinization are located between Nea Kallikratia-Epanomi and Aggelochori-Peraia. According to the ERTs, in the influenced areas the salinization of the aquifer exceeds 1 km toward the mainland and its depth reaches 200 m. In the area surrounding Thessaloniki airport, the ERTs revealed salinization of the upper aquifer to depths of up to 40 m, whereas the lower aquifer is uninfluenced. This abnormal distribution of seawater intrusion demonstrates the value of geoelectrical methods in the study of seawater intrusion especially in areas with limited available hydrochemical data. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Efficient purification and concentration of viruses from a large body of high turbidity seawater.

    Science.gov (United States)

    Sun, Guowei; Xiao, Jinzhou; Wang, Hongming; Gong, Chaowen; Pan, Yingjie; Yan, Shuling; Wang, Yongjie

    2014-01-01

    Marine viruses are the most abundant entities in the ocean and play crucial roles in the marine ecological system. However, understanding of viral diversity on large scale depends on efficient and reliable viral purification and concentration techniques. Here, we report on developing an efficient method to purify and concentrate viruses from large body of high turbidity seawater. The developed method characterizes with high viral recovery efficiency, high concentration factor, high viral particle densities and high-throughput, and is reliable for viral concentration from high turbidity seawater. Recovered viral particles were used directly for subsequent analysis by epifluorescence microscopy, transmission electron microscopy and metagenomic sequencing. Three points are essential for this method:•The sampled seawater (>150 L) was initially divided into two parts, water fraction and settled matter fraction, after natural sedimentation.•Both viruses in the water fraction concentrated by tangential flow filtration (TFF) and viruses isolated from the settled matter fraction were considered as the whole viral community in high turbidity seawater.•The viral concentrates were re-concentrated by using centrifugal filter device in order to obtain high density of viral particles.

  14. Sulphide production and corrosion in seawaters during exposure to FAME diesel.

    Science.gov (United States)

    Lee, Jason S; Ray, Richard I; Little, Brenda J; Duncan, Kathleen E; Oldham, Athenia L; Davidova, Irene A; Suflita, Joseph M

    2012-01-01

    Experiments were designed to evaluate the corrosion-related consequences of storing/transporting fatty acid methyl ester (FAME) alternative diesel fuel in contact with natural seawater. Coastal Key West, FL (KW), and Persian Gulf (PG) seawaters, representing an oligotrophic and a more organic- and inorganic mineral-rich environment, respectively, were used in 60 day incubations with unprotected carbon steel. The original microflora of the two seawaters were similar with respect to major taxonomic groups but with markedly different species. After exposure to FAME diesel, the microflora of the waters changed substantially, with Clostridiales (Firmicutes) becoming dominant in both. Despite low numbers of sulphate-reducing bacteria in the original waters and after FAME diesel exposure, sulphide levels and corrosion increased markedly due to microbial sulphide production. Corrosion morphology was in the form of isolated pits surrounded by an intact, passive surface with the deepest pits associated with the fuel/seawater interface in the KW exposure. In the presence of FAME diesel, the highest corrosion rates measured by linear polarization occurred in the KW exposure correlating with significantly higher concentrations of sulphur and chlorine (presumed sulphide and chloride, respectively) in the corrosion products.

  15. Seawater desalination with solar-energy-integrated vacuum membrane distillation system

    Directory of Open Access Journals (Sweden)

    Fang Wang

    2017-03-01

    Full Text Available This study designed and tested a novel type of solar-energy-integrated vacuum membrane distillation (VMD system for seawater desalination under actual environmental conditions in Wuhan, China. The system consists of eight parts: a seawater tank, solar collector, solar cooker, inclined VMD evaporator, circulating water vacuum pump, heat exchanger, fresh water tank, and brine tank. Natural seawater was used as feed and a hydrophobic hollow-fiber membrane module was used to improve seawater desalination. The experiment was conducted during a typical summer day. Results showed that when the highest ambient temperature was 33 °C, the maximum value of the average solar intensity was 1,080 W/m2. The system was able to generate 36 kg (per m2 membrane module distilled fresh water during 1 day (7:00 am until 6:00 pm, the retention rate was between 99.67 and 99.987%, and electrical conductivity was between 0.00276 and 0.0673 mS/cm. The average salt rejection was over 90%. The proposed VMD system shows favorable potential application in desalination of brackish waters or high-salt wastewater treatment, as well.

  16. Predicting and measurement of pH of seawater reverse osmosis concentrates

    KAUST Repository

    Waly, Tarek

    2011-10-01

    The pH of seawater reverse osmosis plants (SWRO) is the most influential parameter in determining the degree of supersaturation of CaCO3 in the concentrate stream. For this, the results of pH measurements of the concentrate of a seawater reverse osmosis pilot plant were compared with pH calculations based on the CO2-HCO3 --CO3 2- system equilibrium equations. Results were compared with two commercial software programs from membrane suppliers and also the software package Phreeqc. Results suggest that the real concentrate pH is lower than that of the feed and that none of the used programs was able to predict correctly real pH values. In addition, the effect of incorporating the acidity constant calculated for NaCl medium or seawater medium showed a great influence on the concentrate pH determination. The HCO3 - and CO3 2- equilibrium equation using acidity constants developed for seawater medium was the only method able to predict correctly the concentrate pH. The outcome of this study indicated that the saturation level of the concentrate was lower than previously anticipated. This was confirmed by shutting down the acid and the antiscalants dosing without any signs of scaling over a period of 12 months. © 2011 Elsevier B.V.

  17. The Degradation of Mechanical Properties in Halloysite Nanoclay-Polyester Nanocomposites Exposed in Seawater Environment

    Directory of Open Access Journals (Sweden)

    Mohd Shahneel Saharudin

    2016-01-01

    Full Text Available Polyester based polymers are extensively used in aggressive marine environments; however, inadequate data is available on the effects of the seawater on the polyester based nanocomposites mechanical properties. This paper reports the effect of seawater absorption on the mechanical properties degradation of halloysite nanoclay-polyester nanocomposites. Results confirmed that the addition of halloysite nanoclay into polyester matrix was found to increase seawater uptake and reduce mechanical properties compared to monolithic polyester. The maximum decreases in microhardness, tensile and flexural properties, and impact toughness were observed in case of 1 wt% nanoclay. The microhardness decreased from 107 HV to 41.7 HV (61% decrease. Young’s modulus decreased from 0.6 GPa to 0.4 GPa (33% decrease. The flexural modulus decreased from 0.6 GPa to 0.34 GPa (43% decrease. The impact toughness dropped from 0.71 kJ/m2 to 0.48 kJ/m2 (32% decrease. Interestingly, the fracture toughness KIC increased with the addition of halloysite nanoclay due to the plasticization effect of the resin matrix. SEM images revealed the significant reduction in mechanical properties in case of 1 wt% reinforcement which is attributed to the degradation of the nanoclay-matrix interface influenced by seawater absorption and agglomeration of halloysite nanoclay.

  18. Simultaneous Extraction of Lithium and Hydrogen from Seawater

    Science.gov (United States)

    2011-08-22

    N00014-10-M-0234 20126083 0001AD Dr. Pyoungho Choi University of Central Florida/Florida Solar Energy Center 1679 Clearlake Road Cocoa FL 32922-5703...South America (Bolivia and Chile), Australia, and China. There have been debates as to whether the lithium supplies would meet the surging demand...extract the lithium in seawater should be developed [1]. Seawater is also the ultimate source of hydrogen. The production of hydrogen from seawater is

  19. Distributed Memory Parallel Computing with SEAWAT

    Science.gov (United States)

    Verkaik, J.; Huizer, S.; van Engelen, J.; Oude Essink, G.; Ram, R.; Vuik, K.

    2017-12-01

    Fresh groundwater reserves in coastal aquifers are threatened by sea-level rise, extreme weather conditions, increasing urbanization and associated groundwater extraction rates. To counteract these threats, accurate high-resolution numerical models are required to optimize the management of these precious reserves. The major model drawbacks are long run times and large memory requirements, limiting the predictive power of these models. Distributed memory parallel computing is an efficient technique for reducing run times and memory requirements, where the problem is divided over multiple processor cores. A new Parallel Krylov Solver (PKS) for SEAWAT is presented. PKS has recently been applied to MODFLOW and includes Conjugate Gradient (CG) and Biconjugate Gradient Stabilized (BiCGSTAB) linear accelerators. Both accelerators are preconditioned by an overlapping additive Schwarz preconditioner in a way that: a) subdomains are partitioned using Recursive Coordinate Bisection (RCB) load balancing, b) each subdomain uses local memory only and communicates with other subdomains by Message Passing Interface (MPI) within the linear accelerator, c) it is fully integrated in SEAWAT. Within SEAWAT, the PKS-CG solver replaces the Preconditioned Conjugate Gradient (PCG) solver for solving the variable-density groundwater flow equation and the PKS-BiCGSTAB solver replaces the Generalized Conjugate Gradient (GCG) solver for solving the advection-diffusion equation. PKS supports the third-order Total Variation Diminishing (TVD) scheme for computing advection. Benchmarks were performed on the Dutch national supercomputer (https://userinfo.surfsara.nl/systems/cartesius) using up to 128 cores, for a synthetic 3D Henry model (100 million cells) and the real-life Sand Engine model ( 10 million cells). The Sand Engine model was used to investigate the potential effect of the long-term morphological evolution of a large sand replenishment and climate change on fresh groundwater resources

  20. The influence of wind direction on natural ventilation: application to a large semi-enclosed stadium

    NARCIS (Netherlands)

    Hooff, van T.A.J.; Blocken, B.J.E.

    2009-01-01

    Natural ventilation is still a commonly applied way in building engineering to ensure a healthy and comfortable indoor climate. In this paper CFD simulations of the natural ventilation of a large semi-enclosed stadium in the Netherlands during the summer are described. Simulations are performed to

  1. Institutional influences on the provision of after-school nature programs

    Science.gov (United States)

    James D. Absher; Anne S. Fege; Leanne Jacobson

    2015-01-01

    This study examines the institutional factors that affect organizations' decisions to offer after-school nature programs. Data are from interviews of 31 staff and administrators of after-school programs in San Diego, CA. Results show support for the importance of nature education experiences in general, and that such activities are more likely to be offered if...

  2. The influence of prices formation system for natural gas over the sector development

    International Nuclear Information System (INIS)

    Drummond, P.H.

    1988-01-01

    An analysis of the existing methodologies concerning natural gas valorization in developing countries is presented. The characteristics of natural gas production, transport and distribution in Brazil, with the purpose of suggesting a pricing policy which could effectively permit its development on a national basis is also described. (author)

  3. Influence of pH, Temperature and Sample Size on Natural and Enforced Syneresis of Precipitated Silica

    Directory of Open Access Journals (Sweden)

    Sebastian Wilhelm

    2015-12-01

    Full Text Available The production of silica is performed by mixing an inorganic, silicate-based precursor and an acid. Monomeric silicic acid forms and polymerizes to amorphous silica particles. Both further polymerization and agglomeration of the particles lead to a gel network. Since polymerization continues after gelation, the gel network consolidates. This rather slow process is known as “natural syneresis” and strongly influences the product properties (e.g., agglomerate size, porosity or internal surface. “Enforced syneresis” is the superposition of natural syneresis with a mechanical, external force. Enforced syneresis may be used either for analytical or preparative purposes. Hereby, two open key aspects are of particular interest. On the one hand, the question arises whether natural and enforced syneresis are analogous processes with respect to their dependence on the process parameters: pH, temperature and sample size. On the other hand, a method is desirable that allows for correlating natural and enforced syneresis behavior. We can show that the pH-, temperature- and sample size-dependency of natural and enforced syneresis are indeed analogous. It is possible to predict natural syneresis using a correlative model. We found that our model predicts maximum volume shrinkages between 19% and 30% in comparison to measured values of 20% for natural syneresis.

  4. Temporal Patterns in Seawater Quality from Dredging in Tropical Environments.

    Directory of Open Access Journals (Sweden)

    Ross Jones

    Full Text Available Maintenance and capital dredging represents a potential risk to tropical environments, especially in turbidity-sensitive environments such as coral reefs. There is little detailed, published observational time-series data that quantifies how dredging affects seawater quality conditions temporally and spatially. This information is needed to test realistic exposure scenarios to better understand the seawater-quality implications of dredging and ultimately to better predict and manage impacts of future projects. Using data from three recent major capital dredging programs in North Western Australia, the extent and duration of natural (baseline and dredging-related turbidity events are described over periods ranging from hours to weeks. Very close to dredging i.e. <500 m distance, a characteristic features of these particular case studies was high temporal variability. Over several hours suspended sediment concentrations (SSCs can range from 100-500 mg L-1. Less turbid conditions (10-80 mg L-1 can persist over several days but over longer periods (weeks to months averages were <10 mg L-1. During turbidity events all benthic light was sometimes extinguished, even in the shallow reefal environment, however a much more common feature was very low light 'caliginous' or daytime twilight periods. Compared to pre-dredging conditions, dredging increased the intensity, duration and frequency of the turbidity events by 10-, 5- and 3-fold respectively (at sites <500 m from dredging. However, when averaged across the entire dredging period of 80-180 weeks, turbidity values only increased by 2-3 fold above pre-dredging levels. Similarly, the upper percentile values (e.g., P99, P95 of seawater quality parameters can be highly elevated over short periods, but converge to values only marginally above baseline states over longer periods. Dredging in these studies altered the overall probability density distribution, increasing the frequency of extreme values. As

  5. Research into the effects of seawater velocity variation on migration imaging in deep-water geology

    Directory of Open Access Journals (Sweden)

    Hui Sun

    2016-07-01

    Full Text Available This paper aims at the problem that in deep water the migration quality is poor, and starts with the influence that velocity model accuracy has on migration, studying influence that variable seawater velocity makes on migration effect. At first, variable seawater velocity influenced by temperature, pressure and salinity is defined to replace the true seawater velocity. Then variable seawater velocity’s influence on interface migration location, layer sickness and migration energy focusing degree are analyzed in theory. And finally a deep water layered medium model containing variable seawater velocity, a syncline wedge shape model and a complex seafloor velocity model are constructed. By changing the seawater velocity of each model and comparing migration results of constant seawater-velocity model and variable seawater-velocity model, we can draw the conclusion: Under the condition of deep water, variable seawater-velocity’s impact on the quality of seismic migration is significant, which not only can change the location of geologic body migration result, but also can influence the resolution of geologic interface in the migration section and maybe can cause migration illusion.   Investigación de los efectos de la variación en la velocidad del agua marina sobre las imágenes de migración en la geología de aguas profundas Resumen Este artículo se enfoca en el problema de la baja calidad de la migración en aguas profundas. Se analiza la influencia que tiene el modelo de precisión de velocidad en la migración y se estudia el impacto que la variación de velocidad del agua marina tiene en el efecto de movimiento. En primera instancia, se define la variación de la velocidad del agua marina afectada por la temperatura, la presión y la salinidad para reemplazar la velocidad del agua marina actual. Luego se analiza la teoría de la influencia de la velocidad del agua marina sobre la interfaz de la ubicación de migración, el grosor de

  6. Sample preparation and electrochemical data of Co3O4 working electrode for seawater splitting

    Directory of Open Access Journals (Sweden)

    Malkeshkumar Patel

    2017-10-01

    Full Text Available In this data article, we presented the electrochemical data of the working electrode made of Co3O4 semi-transparent film. Electrochemically stable, porous nature of Kirkendall-diffusion grown Co3O4 films were applied to generate hydrogen from the seawater splitting (Patel et al., 2017 [1]. The data presented in this article includes the photograph of prepared samples, polarization curves for water oxidation and Tafel plot, linear sweep voltammetry measurements under the pulsed light condition in 0.1 M Na2S2O3 electrolyte, and transient photoresponses with natural sea water. Moreover, seawater splitting using the Co3O4 working electrode is demonstrated.

  7. Effect of Greenhouse Gases Dissolved in Seawater

    Directory of Open Access Journals (Sweden)

    Shigeki Matsunaga

    2015-12-01

    Full Text Available A molecular dynamics simulation has been performed on the greenhouse gases carbon dioxide and methane dissolved in a sodium chloride aqueous solution, as a simple model of seawater. A carbon dioxide molecule is also treated as a hydrogen carbonate ion. The structure, coordination number, diffusion coefficient, shear viscosity, specific heat, and thermal conductivity of the solutions have been discussed. The anomalous behaviors of these properties, especially the negative pressure dependence of thermal conductivity, have been observed in the higher-pressure region.

  8. Mortality of fecal bacteria in seawater

    International Nuclear Information System (INIS)

    Garcia-Lara, J.; Menon, P.; Servais, P.; Billen, G.

    1991-01-01

    The authors propose a method for determining the mortality rate for allochthonous bacteria released in aquatic environments without interference due to the loss of culturability in specific culture media. This method consists of following the disappearance of radioactivity from the trichloracetic acid-insoluble fraction in water samples to which [ 3 H]thymidine-prelabeled allochthonous bacteria have been added. In coastal seawater, they found that the actual rate of disappearance of fecal bacteria was 1 order of magnitude lower than the rate of loss of culturability on specific media. Minor adaptation of the procedure may facilitate assessment of the effect of protozoan grazing and bacteriophage lysis on the overall bacterial mortality rate

  9. Enhancement of Extraction of Uranium from Seawater

    Energy Technology Data Exchange (ETDEWEB)

    Al-Sheikhly, Mohamad [Univ. of Maryland, College Park, MD (United States); Dietz, Travis [Univ. of Maryland, College Park, MD (United States); Tsinas, Zois [Univ. of Maryland, College Park, MD (United States); Tomaszewski, Claire [Univ. of Maryland, College Park, MD (United States); Pazos, Ileana M. [Univ. of Maryland, College Park, MD (United States); Nigliazzo, Olga [The Catholic Univ. of America, Washington, DC (United States); Li, Weixing [The Catholic Univ. of America, Washington, DC (United States); Adel-Hadadi, Mohamad [Univ. of Maryland, College Park, MD (United States); Barkatt, Aaron [Univ. of Palermo (Italy)

    2016-04-01

    Even at a concentration of 3 μg/L, the world’s oceans contain a thousand times more uranium than currently know terrestrial sources. In order to take advantage of this stockpile, methods and materials must be developed to extract it efficiently, a difficult task considering the very low concentration of the element and the competition for extraction by other atoms in seawater such as sodium, calcium, and vanadium. The majority of current research on methods to extract uranium from seawater are vertical explorations of the grafting of amidoxime ligand, which was originally discovered and promoted by Japanese studies in the late 1980s. Our study expands on this research horizontally by exploring the effectiveness of novel uranium extraction ligands grafted to the surface of polymer substrates using radiation. Through this expansion, a greater understanding of uranium binding chemistry and radiation grafting effects on polymers has been obtained. While amidoxime-functionalized fabrics have been shown to have the greatest extraction efficiency so far, they suffer from an extensive chemical processing step which involves treatment with powerful basic solutions. Not only does this add to the chemical waste produced in the extraction process and add to the method’s complexity, but it also significantly impacts the regenerability of the amidoxime fabric. The approach of this project has been to utilize alternative, commercially available monomers capable of extracting uranium and containing a carbon-carbon double bond to allow it to be grafted using radiation, specifically phosphate, oxalate, and azo monomers. The use of commercially available monomers and radiation grafting with electron beam or gamma irradiation will allow for an easily scalable fabrication process once the technology has been optimized. The need to develop a cheap and reliable method for extracting uranium from seawater is extremely valuable to energy independence and will extend the quantity of

  10. Determination of radioactive strontium in seawater

    International Nuclear Information System (INIS)

    Grahek, Zeljko; Rozmaric Macefat, Martina

    2005-01-01

    This paper describes the procedures of isolating strontium and yttrium from seawater that enable the determination of 89,90 Sr. In one procedure, strontium is directly isolated from seawater on the column filled with Sr resin by binding of strontium to the resin from 3 M HNO 3 in a seawater, and successive elution with HNO 3 . In others, strontium is precipitated from seawater with (NH 4 ) 2 CO 3 , followed by isolation on a Sr column or an anion exchange column. It is shown that strontium precipitation is optimal with concentration of 0.3 M (NH 4 ) 2 CO 3 at pH = 11. In these conditions, 100% Y, 78% Sr, 80% Ca and 50% Mg are precipitated. Strontium is bound on to Sr column from 5 to 8 M HNO 3 , separated from other elements by elution with 3 M HNO 3 and 0.05 M HNO 3 . Strontium and yttrium are bound on to anion exchange column from alcoholic solutions of nitric acid. The optimum mixture of alcohols for sample binding is a mixture of ethanol and methanol with the volume ratio 1:3. Strontium and yttrium are separated from Mg, Ca, K, and other elements by elution with 0.25 M HNO 3 in the mixture of ethanol and methanol. After the separation, yttrium and strontium are eluted from the column with water or methanol. In the procedure of direct isolation from 1 l of the sample, the average recovery of 50% was obtained. In the remaining two procedures, the strontium recovery was about 60% for the Sr column and 65% for anion exchange column. Recovery of yttrium is about 70% for the anion exchange column. It turned out that the procedure with the Sr resin (direct isolation and isolation after precipitation) is simpler and faster in the phase of the isolation on the column in comparison with the procedure with the anion exchanger. The procedure with the anion exchanger, however, enables the simultaneous isolation of yttrium and strontium and rapid determination of 89,90 Sr. These procedures were tested by determination of 89,90 Sr on liquid scintillation counter and Cherenkov

  11. Enhancement of Extraction of Uranium from Seawater

    International Nuclear Information System (INIS)

    Al-Sheikhly, Mohamad; Dietz, Travis; Tsinas, Zois; Tomaszewski, Claire; Pazos, Ileana M.; Nigliazzo, Olga; Li, Weixing; Adel-Hadadi, Mohamad; Barkatt, Aaron

    2016-01-01

    Even at a concentration of 3 @@g/L, the world@@@s oceans contain a thousand times more uranium than currently know terrestrial sources. In order to take advantage of this stockpile, methods and materials must be developed to extract it efficiently, a difficult task considering the very low concentration of the element and the competition for extraction by other atoms in seawater such as sodium, calcium, and vanadium. The majority of current research on methods to extract uranium from seawater are vertical explorations of the grafting of amidoxime ligand, which was originally discovered and promoted by Japanese studies in the late 1980s. Our study expands on this research horizontally by exploring the effectiveness of novel uranium extraction ligands grafted to the surface of polymer substrates using radiation. Through this expansion, a greater understanding of uranium binding chemistry and radiation grafting effects on polymers has been obtained. While amidoxime-functionalized fabrics have been shown to have the greatest extraction efficiency so far, they suffer from an extensive chemical processing step which involves treatment with powerful basic solutions. Not only does this add to the chemical waste produced in the extraction process and add to the method@@@s complexity, but it also significantly impacts the regenerability of the amidoxime fabric. The approach of this project has been to utilize alternative, commercially available monomers capable of extracting uranium and containing a carbon-carbon double bond to allow it to be grafted using radiation, specifically phosphate, oxalate, and azo monomers. The use of commercially available monomers and radiation grafting with electron beam or gamma irradiation will allow for an easily scalable fabrication process once the technology has been optimized. The need to develop a cheap and reliable method for extracting uranium from seawater is extremely valuable to energy independence and will extend the quantity of

  12. Use of a two-step ultrafiltration procedure to concentrate viral hemorrhagic septicemia virus (VHSV) in seawater.

    Science.gov (United States)

    Kim, Soo-Jin; Kim, Jong-Oh; Kim, Wi-Sik; Oh, Myung-Joo

    2015-11-01

    Viral hemorrhagic septicemia virus (VHSV) has been reported to be stable in both fresh as well as seawater, suggesting that VHSV exists in natural aquatic environments and might have an effect on the wild and cultured fish. However, VHSV is below the detectable limits of laboratory tests in natural seawater. In this study, a two-step ultrafiltration (UF) procedure was used to concentration of VHSV in seawater, providing samples that were tested for infectivity by cell culture and the presence of VHSV by quantitative reverse transcriptase PCR (qRT-PCR) methods. Overall, VHSV was approximately concentrated 100-1000 times in 1, 5 and 10 L, seawater volumes respectively: from 2.81×10(6) to 6.53×10(7)/mL and 10(3.3) to 10(3.8)TCID50/mL prior to the UF procedure, to 3.78×10(8), 1.16 × 10(11), and 9.12 × 10(10)/mL after the procedure. This is the first report of concentrating VHSV using an UF method that was specifically designed for seawater samples. In addition, the two-step UF procedure appears to be compatible with viral cell culture and qRT-PCR methods. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. The influence and analysis of natural crosswind on cooling characteristics of the high level water collecting natural draft wet cooling tower

    Science.gov (United States)

    Ma, Libin; Ren, Jianxing

    2018-01-01

    Large capacity and super large capacity thermal power is becoming the main force of energy and power industry in our country. The performance of cooling tower is related to the water temperature of circulating water, which has an important influence on the efficiency of power plant. The natural draft counter flow wet cooling tower is the most widely used cooling tower type at present, and the high cooling tower is a new cooling tower based on the natural ventilation counter flow wet cooling tower. In this paper, for high cooling tower, the application background of high cooling tower is briefly explained, and then the structure principle of conventional cooling tower and high cooling tower are introduced, and the difference between them is simply compared. Then, the influence of crosswind on cooling performance of high cooling tower under different wind speeds is introduced in detail. Through analysis and research, wind speed, wind cooling had little impact on the performance of high cooling tower; wind velocity, wind will destroy the tower inside and outside air flow, reducing the cooling performance of high cooling tower; Wind speed, high cooling performance of cooling tower has increased, but still lower than the wind speed.

  14. RESEARCH OF MICROWAVE DRYING OF NATURAL ZEOLITE GRANULES AND ITS INFLUENCE ON THE TECHNOLOGICAL PROPERTIES

    Directory of Open Access Journals (Sweden)

    Rybachuk V.D.

    2016-06-01

    . The results of experimental studies have shown a significant impact of intensity microwave radiation on the rate of drying material. With an increase in power from 119 watts to 700 watts time spent on drying decreased more than twice. Changing the speed of drying material took place in two periods. In the first period (humidity of 0,29-0,05 g.w./g.d.m. free moisture located mainly on the surface of the granules is removed in the first period, in the second period (0,04-0,05 g.w./g.d.m. moisture from the inner pores of the material is removed. Type of drying does not significantly affect the distribution of particle size. Different amounts of microwave radiation also not significantly affect the size and rheological properties of the granules. The last one was confirmed by values of Carr`s index and coefficient of Hausner. Both indicators showed that all series of obtained granules have very good flowability. Study of the influence of specific humidity values on the mechanical strength of granules and tablets obtained on the basis showed that its most optimal level, which can be recommended both for granules and for tablets, is based on their range of 0,03-0,05 g.w./g.d.m. Knowing the limits of specific humidity allows to choose optimal modes of power microwave radiation for drying a natural zeolite granules. Conclusion. The effect of microwave radiation on the dynamics of natural zeolite pellets drying on the value of their technological properties. Optimal levels of specific humidity for granules and tablets, providing the best technological properties, is 0,03-0,05 g.w./g.d.m. On the basis of data obtained, the reasonable duration of the process of drying, depending on the power of the microwave radiation, is 3-14 minutes.

  15. Mechanisms of Corrosion of Copper-Nickel Alloys in Sulfide-Polluted Seawater

    Science.gov (United States)

    1981-02-01

    anaerobic bacteria, which convert the natural sulfate content of the seawater into sulfides. Also, the putrefaction of organic compounds containing...corrosion rate bozause the Cu2 0 growth3 292 probably follows a parabolic rate law. The corrosion behavior at high oxygen concentrations (> 7.0 g/m ) is...determined using the rotating ring disk electrode method or SRI’s recently developed rotating cylinder- collector electrode.3 In these methods, the

  16. Influence of reactor design on the establishment of natural circulation in pool-type LMFBR

    International Nuclear Information System (INIS)

    Durham, M.E.

    1976-01-01

    The general principles involved in establishing natural circulation in a pool-type liquid metal cooled fast breeder reactor following loss of a.c. supplies are elucidated and the effects of design features by use of the computer code MELANI are quantified. It is shown that natural circulation can provide a feasible means of emergency core cooling in addition to that provided by pony motors. The choice of primary pump rundown time has a significant effect in controlling peak core outlet temperatures in the hypothetical case of natural circulation alone being the core heat removal process. (author)

  17. Review on influences of colloids on geologic disposal of high level radioactive waste. For better understanding of natural colloidal materials

    International Nuclear Information System (INIS)

    Kanai, Yutaka; Suzuki, Masaya; Kamioka, Hikari; Yoshida, Takahiro; Suko, Takeshi

    2007-01-01

    Although the influences of colloidal materials on radionuclide transport in geological media are pointed out, their behaviors in natural environment have not yet been well elucidated and therefore their influences on the geologic disposal of high-level radioactive waste (HLW) are not fully estimated quantitatively. This paper reviewed the studies on natural colloids, especially focused on inorganic, organic and biological colloids, and discussed the future works to be carried out. Much attention should be paid to the sampling and analysis. Excellent techniques for in-situ observation, concentration without changing the state of colloid, standard procedure for analysis, are necessary to be developed. More research studies on the behaviors of colloids are required in not only far- and near-fields but also items on effects of the environments and its evolution. (author)

  18. The strontium isotopic composition of seawater, and seawater-oceanic crust interaction

    International Nuclear Information System (INIS)

    Spooner, E.T.C.

    1976-01-01

    The 87 Sr/ 86 Sr ratio of seawater strontium (0.7091) is less than the 87 Sr/ 86 Sr ratio of dissolved strontium delivered to the oceans by continental run-off (approximately 0.716). Isotope exchange with strontium isotopically lighter oceanic crust during hydrothermal convection within spreading oceanic ridges can explain this observation. In quantitative terms, the current 87 Sr/ 86 Sr ratio of seawater (0.7091) may be maintained by balancing the continental run-off flux of strontium (0.59 x 10 12 g/yr) against a hydrothermal recirculation flux of 3.6 x 10 12 g/yr, during which the 87 Sr/ 86 Sr ratio of seawater drops by 0.0011. A concomitant mean increase in the 87 Sr/ 86 Sr ratio of the upper 4.5 km of oceanic crust of 0.0010 (0.7029-0.7039) should be produced. This required 87 Sr enrichment has been observed in hydrothermally metamorphosed ophiolitic rocks from the Troodos Massif, Cyprus. The post-Upper Cretaceous increase in the strontium isotopic composition of seawater (approximately 0.7075-0.7091) covaries smoothly with inferred increase in land area. This suggests that during this period the main factor which has caused variability in the 87 Sr/ 86 Sr ratio of seawater strontium could have been variation in the magnitude of the continental run-off flux caused by variation in land area. Variations in land area may themselves have been partly a consequence of variations in global mean sea-floor spreading rate. (Auth.)

  19. Environmental setting and natural factors and human influences affecting water quality in the White River Basin, Indiana

    Science.gov (United States)

    Schnoebelen, Douglas J.; Fenelon, Joseph M.; Baker, Nancy T.; Martin, Jeffrey D.; Bayless, E. Randall; Jacques, David V.; Crawford, Charles G.

    1999-01-01

    The White River Basin drains 11,349 square miles of central and southern Indiana and is one of 59 Study Units selected for water-quality assessment as part of the U.S. Geological Survey's National WaterQuality Assessment Program. Defining the environmental setting of the basin and identifying the natural factors and human influences that affect water quality are important parts of the assessment.

  20. Post-Mesozoic Rapid Increase of Seawater Mg/Ca due to Enhanced Mantle-Seawater Interaction

    OpenAIRE

    Marco Ligi; Enrico Bonatti; Marco Cuffaro; Daniele Brunelli

    2013-01-01

    The seawater Mg/Ca ratio increased significantly from ~ 80?Ma to present, as suggested by studies of carbonate veins in oceanic basalts and of fluid inclusions in halite. We show here that reactions of mantle-derived peridotites with seawater along slow spreading mid-ocean ridges contributed to the post-Cretaceous Mg/Ca increase. These reactions can release to modern seawater up to 20% of the yearly Mg river input. However, no significant peridotite-seawater interaction and Mg-release to the ...

  1. Study of natural convection heat transfer characteristics. (1) Influence of ventilation duct height

    International Nuclear Information System (INIS)

    Wakamatsu, Mitsuo; Iwaki, Chikako; Ikeda, Tatsumi; Morooka, Shinichi; Ikeda, Hiroshi; Nakada, Kotaro; Masaki, Yoshikazu

    2008-01-01

    Natural cooling system has been investigated in waste storage. It is important to evaluate the flow by natural draft enough to removal the decay heat from the waste. In this study, we carried out the fundamental experiment of ventilation duct height effect for natural convection on vertical cylindrical heater in atmospheric air. The scale of test facility is about 4m height with single heater. The heating value is varied in the range of 33-110W, where Rayleigh number is over 10 10 . Natural convection flow rate were calculated by measured velocity with thermo anemometer in the inlet duct. The temperature of the cylindrical heater wall and fluid were measured with thermocouples. It was found that the heat transfer coefficient difference between long duct and short duct is small in this experiment. (author)

  2. Natural fluctuations in nearshore turbidity and the relative influences of beach renourishment

    OpenAIRE

    Dompe, Philip E.

    1993-01-01

    Turbidity is a measure of the clarity of water. Turbidity depends upon the scattering and absorption of light by suspended particles. The focus of this study was to obtain quantitative measurements of turbidity in the nearshore zone, along with measurements of associated wave parameters and currents occurring naturally and during a beach nourishment project. The objectives were to make quantitative and qualitative comparisons between natural events and those induced by the dred...

  3. The influence of temperature and reaction time in the degradation of natural rubber latex

    International Nuclear Information System (INIS)

    Siti Zaleha Isa; Rosiyah Yahya; Aziz Hassan; Mohd Tahir

    2007-01-01

    Liquid natural rubber (LNR /LENR) should be considered as a new material instead of a new type of rubber though they have the same configuration as the rubber used. In this work, thermal degradation of natural rubber latex was carried out to obtain LNR/LENR by varying the reaction time at different temperatures. The degraded polymers were characterized structurally using FTIR and NMR spectroscopies and the average molecular weights were determined by membrane-osmometry and viscometry. (author)

  4. Seawater intrusion mapping using electrical resistivity tomography and hydrochemical data. An application in the coastal area of eastern Thermaikos Gulf, Greece

    International Nuclear Information System (INIS)

    Kazakis, N.; Pavlou, A.; Vargemezis, G.; Voudouris, K.S.; Soulios, G.; Pliakas, F.; Tsokas, G.

    2016-01-01

    The aim of this study was to determine the extent and geometrical characteristics of seawater intrusion in the coastal aquifer of the eastern Thermaikos Gulf, Greece. Hydrochemical data and geoelectrical measurements were combined and supplemented to determine the hydrochemical regime of the study site in regard to seawater phenomena. Chemical analysis of groundwater was performed in 126 boreholes and fifteen electrical resistivity tomographies (ERT) were measured, whereas in two sites the ERT measurements were repeated following the wet season. The Cl"− concentrations recorded reached 2240 mg/L indicating seawater intrusion which was also verified by ionic ratios. The ionic ratios were overlapped and a seawater intrusion map (SWIM) was produced. A significant part of the coastal aquifer (up to 150 km"2) is influenced by seawater intrusion. The areas with the most intensive salinization are located between Nea Kallikratia–Epanomi and Aggelochori–Peraia. According to the ERTs, in the influenced areas the salinization of the aquifer exceeds 1 km toward the mainland and its depth reaches 200 m. In the area surrounding Thessaloniki airport, the ERTs revealed salinization of the upper aquifer to depths of up to 40 m, whereas the lower aquifer is uninfluenced. This abnormal distribution of seawater intrusion demonstrates the value of geoelectrical methods in the study of seawater intrusion especially in areas with limited available hydrochemical data. - Highlights: • ERTs determined the geometrical characteristics of the saline aquifer. • An abnormal distribution of seawater intrusion was recorded. • Four ionic ratios overlapped and a seawater intrusion map was produced. • Cl"− concentrations increased significantly from 2005 to 2010 by up to 1800 mg/L.

  5. Seawater intrusion mapping using electrical resistivity tomography and hydrochemical data. An application in the coastal area of eastern Thermaikos Gulf, Greece

    Energy Technology Data Exchange (ETDEWEB)

    Kazakis, N., E-mail: kazanera@yahoo.com [Aristotle University of Thessaloniki, Department of Geology, Lab. of Engineering Geology & Hydrogeology, 54124 Thessaloniki (Greece); Pavlou, A. [Aristotle University of Thessaloniki, Department of Geology, Lab. of Engineering Geology & Hydrogeology, 54124 Thessaloniki (Greece); Vargemezis, G. [Aristotle University of Thessaloniki, Department of Geology, Lab. of Applied Geophysics, 54124 Thessaloniki (Greece); Voudouris, K.S.; Soulios, G. [Aristotle University of Thessaloniki, Department of Geology, Lab. of Engineering Geology & Hydrogeology, 54124 Thessaloniki (Greece); Pliakas, F. [Democritus University of Thrace, Department of Civil Engineering, Xanthi 67100 (Greece); Tsokas, G. [Aristotle University of Thessaloniki, Department of Geology, Lab. of Applied Geophysics, 54124 Thessaloniki (Greece)

    2016-02-01

    The aim of this study was to determine the extent and geometrical characteristics of seawater intrusion in the coastal aquifer of the eastern Thermaikos Gulf, Greece. Hydrochemical data and geoelectrical measurements were combined and supplemented to determine the hydrochemical regime of the study site in regard to seawater phenomena. Chemical analysis of groundwater was performed in 126 boreholes and fifteen electrical resistivity tomographies (ERT) were measured, whereas in two sites the ERT measurements were repeated following the wet season. The Cl{sup −} concentrations recorded reached 2240 mg/L indicating seawater intrusion which was also verified by ionic ratios. The ionic ratios were overlapped and a seawater intrusion map (SWIM) was produced. A significant part of the coastal aquifer (up to 150 km{sup 2}) is influenced by seawater intrusion. The areas with the most intensive salinization are located between Nea Kallikratia–Epanomi and Aggelochori–Peraia. According to the ERTs, in the influenced areas the salinization of the aquifer exceeds 1 km toward the mainland and its depth reaches 200 m. In the area surrounding Thessaloniki airport, the ERTs revealed salinization of the upper aquifer to depths of up to 40 m, whereas the lower aquifer is uninfluenced. This abnormal distribution of seawater intrusion demonstrates the value of geoelectrical methods in the study of seawater intrusion especially in areas with limited available hydrochemical data. - Highlights: • ERTs determined the geometrical characteristics of the saline aquifer. • An abnormal distribution of seawater intrusion was recorded. • Four ionic ratios overlapped and a seawater intrusion map was produced. • Cl{sup −} concentrations increased significantly from 2005 to 2010 by up to 1800 mg/L.

  6. Corrosion of barrier materials in seawater environments

    International Nuclear Information System (INIS)

    Heiser, J.H.; Soo, P.

    1995-07-01

    A brief review has been carried out on the performance of barrier materials for low-level radioactive wastes in seawater environments. The environments include those for shallower coastal waters as well as the deep ocean (down to 3800 m). The review is mainly focused on metallic materials since they are the most common for seawater service and they have the largest data base. Information from the literature is usually pertinent to shallower coastal locations, but there is a valuable source of corrosion data obtained from several studies of metallic specimens exposed to ocean-bed conditions. In addition, the corrosion of carbon steel barriers has been evaluated for actual waste containers that were retrieved from previously-used disposal sites in the Atlantic and Pacific Oceans. Of the metallic materials studied, carbon steel showed the least corrosion resistance. Failure by non-uniform attack in a typical waste container could occur in as little as 25 y in some ocean environments ' Penetration by local attack, such as pitting and crevice corrosion resistance was also observed for more expensive materials such as low-alloy steels, stainless steels, titanium alloys, zirconium alloys, copper alloys, nickel alloys, aluminum alloys, and lead alloys

  7. Desalination of seawater: a nuclear solution

    International Nuclear Information System (INIS)

    Basta, H.

    2003-01-01

    1,4 milliard human beings do not benefit of sufficient clean water supply. The desalting of seawater is a valid and tested solution in terms of technology but the 2 physical processes involved, evaporation and reverse osmosis are energy-greedy. Only rich countries like Kuwait or Saudi-Arabia can afford producing massive volumes of fresh water from seawater. Today the total world capacity of desalting reaches 30 milliard m 3 a day with 10.000 operating units, half of which installed in middle-east countries. The use of nuclear energy is a solution to lower costs. In Aktau (Kazakhstan) a BN-350 fast reactor has been producing a 135 MW electrical output and 80.000 m 3 of fresh water a day for 27 years. In Japan about 10 desalting units have been coupled to nuclear power plants. A company (Eskom) based in South-Africa is developing a new concept of high temperature reactor: the PBMR (pebble bed modular reactor). The suitability of this reactor has been assessed for desalting and it appears that its main assets are its size: 165 MW electrical output (400 MW thermal output) and its Brayton cycle. Other characteristics such as the coolant (helium), the type of fuel (8% enriched uranium encapsulated in carbon), the low design and maintenance costs, the short building time (2 years) are important when considering issues like nuclear safety, non-proliferation and profitability. (A.C.)

  8. On the classification of seawater intrusion

    Science.gov (United States)

    Werner, Adrian D.

    2017-08-01

    Seawater intrusion (SWI) arising from aquifer depletion is often classified as ;active; or ;passive;, depending on whether seawater moves in the same direction as groundwater flow or not. However, recent studies have demonstrated that alternative forms of active SWI show distinctly different characteristics, to the degree that the term ;active SWI; may be misleading without additional qualification. In response, this article proposes to modify hydrogeology lexicon by defining and characterizing three classes of SWI, namely passive SWI, passive-active SWI and active SWI. The threshold parameter combinations for the onset of each form of SWI are developed using sharp-interface, steady-state analytical solutions. Numerical simulation is then applied to a hypothetical case study to test the developed theory and to provide additional insights into dispersive SWI behavior. The results indicate that the three classes of SWI are readily predictable, with the exception of active SWI occurring in the presence of distributed recharge. The key characteristics of each SWI class are described to distinguish their most defining features. For example, active SWI occurring in aquifers receiving distributed recharge only creates watertable salinization downstream of the groundwater mound and only where dispersion effects are significant. The revised classification of SWI proposed in this article, along with the analysis of thresholds and SWI characteristics, provides coastal aquifer custodians with an improved basis upon which to expect salinization mechanisms to impact freshwater availability following aquifer depletion.

  9. Influence de la nature et du dosage en fibres sur le comportement ...

    African Journals Online (AJOL)

    Influence of fiber type and volume contents on the physical and mechanical behaviour of ... obtained compared to reference concrete. ... Key-Words: sandcrete - granulated slag- polypropylene fibers - metallic fibers- mechanical behavior.

  10. Influence of Natural Honey on Biochemical and Hematological Variables in AIDS: A case study

    Directory of Open Access Journals (Sweden)

    Noori S. Al-Waili

    2006-01-01

    Full Text Available Honey lowers prostaglandins and elevates nitric oxide (NO in various biological fluids in normal persons. NO and prostaglandin play a role in pathogenesis of AIDS. The study was designed to assess the effect of natural honey on prostaglandins and NO levels, blood indices and biochemical tests in a 40 year-old woman with AIDS. This presentation is a case story of a 40 year-old women with a long history of AIDS treated with 80g of natural honey. Plasma and urinary prostaglandin F2 alpha and thromboxane B2 levels, plasma, urine and saliva content of NO-end product (total nitrite and hematological tests were estimated before and 3 hours after oral consumption of 80g of natural honey. These variables, in addition to biochemical tests, were re-estimated after 21 days of daily consumption of 80g of natural honey. Results showed that prostaglandins level compared with normal subjects were elevated in patient with AIDS. Natural honey decreased prostaglandins levels, and elevated NO-end product, percentage of lymphocytes, platelet count, and serum protein, albumin and copper levels. It might be concluded that natural honey decreased prostaglandins level, elevated NO production and improved hematological and biochemical tests in a patient with a long history of AIDS.

  11. Patterns and Limitations of Urban Human Mobility Resilience under the Influence of Multiple Types of Natural Disaster.

    Science.gov (United States)

    Wang, Qi; Taylor, John E

    2016-01-01

    Natural disasters pose serious threats to large urban areas, therefore understanding and predicting human movements is critical for evaluating a population's vulnerability and resilience and developing plans for disaster evacuation, response and relief. However, only limited research has been conducted into the effect of natural disasters on human mobility. This study examines how natural disasters influence human mobility patterns in urban populations using individuals' movement data collected from Twitter. We selected fifteen destructive cases across five types of natural disaster and analyzed the human movement data before, during, and after each event, comparing the perturbed and steady state movement data. The results suggest that the power-law can describe human mobility in most cases and that human mobility patterns observed in steady states are often correlated with those in perturbed states, highlighting their inherent resilience. However, the quantitative analysis shows that this resilience has its limits and can fail in more powerful natural disasters. The findings from this study will deepen our understanding of the interaction between urban dwellers and civil infrastructure, improve our ability to predict human movement patterns during natural disasters, and facilitate contingency planning by policymakers.

  12. Determination of the side-reaction coefficient of desferrioxamine B in trace-metal-free seawater

    Directory of Open Access Journals (Sweden)

    Johan Schijf

    2016-07-01

    Full Text Available Electrochemical techniques like adsorptive cathodic stripping voltammetry with competitive ligand equilibration (ACSV-CLE can determine total concentrations of marine organic ligands and their conditional binding constants for specific metals, but cannot identify them. Individual organic ligands, isolated from microbial cultures or biosynthesized through genomics, can be structurally characterized via NMR and tandem MS analysis, but this is tedious and time-consuming. A complementary approach is to compare known properties of natural ligands, particularly their conditional binding constants, with those of model organic ligands, measured under suitable conditions. Such comparisons cannot be meaningfully interpreted unless the side-reaction coefficient (SRC of the model ligand in seawater is thoroughly evaluated.We conducted series of potentiometric titrations, in non-coordinating medium at seawater ionic strength (0.7 M NaClO4 over a range of metal:ligand molar ratios, to study complexation of the siderophore desferrioxamine B (DFOB with Mg and Ca, for which it has the highest affinity among the major seasalt cations. From similar titrations of acetohydroxamic acid in the absence and presence of methanesulfonate (mesylate, it was determined that Mg and Ca binding to this common DFOB counter-ion is not strong enough to interfere with the DFOB titrations. Stability constants were measured for all DFOB complexes with Mg and Ca including, for the first time, the bidentate complexes. No evidence was found for Mg and Ca coordination with the DFOB terminal amine. From the improved DFOB speciation, we calculated five SRCs for each of the five (deprotonated forms of DFOB in trace-metal-free seawater, yet we also present a more convenient definition of a single SRC that allows adjustment of all DFOB stability constants to seawater conditions, no matter which of these forms is selected as the 'component' (reference species. An example of Cd speciation in

  13. Flux dependency of particulate/colloidal fouling in seawater reverse osmosis systems

    KAUST Repository

    Salinas Rodríguez, S. G.

    2012-01-01

    Fouling is the main operational problem in seawater reverse osmosis systems (SWRO). Particulate fouling is traditionally measured through the silt density index (SDI) and through the modified fouling index (MFI). In recent years, ultrafiltration membranes were used successfully at constant flux-MFI-UF-to measure particulate/colloidal fouling potential and tested in sea water applications. Furthermore, constant flux operation allows predicting the rate of fouling in RO systems. The objectives of this study are: (1) to measure the flux effect in MFI-UF with different membranes (100, 30 and 10 kDa) for raw seawater and pre-treated water before reverse osmosis in three different locations; (2) to study the particulate and colloidal fouling potential of seawater in reverse osmosis systems; (3) to project the increase in pressure due to cake resistance in reverse osmosis systems. In this research, flat ultrafiltration membranes (100, 50, 30 and 10 kDa) are used in a con- stant flux filtration mode to test and compare real seawaters from various locations (North and Mediterranean Sea) and from various full scale facilities including different pre-treatments (i.e., ultrafiltration and coagulation + dual media filtration). The operated fluxes range from 350 down to values close to real RO operation, 15l(m2h)-1. After each filtration test, the MFI-UF is calculated to assess the particulate fouling potential. The obtained results showed that: (1) the particulate and colloidal fouling potential is directly proportional to the applied flux during filtration. This proportionality is related to the compression of the cake deposit occurring at high flux values; (2) the higher the flux, the higher the required pressure, the less porous the cake and therefore the higher the specific cake resistance; (3) particulate and colloidal fouling potential of seawater is site specific and is influenced by pre-treatment. © 2012 Desalination Publications. All rights reserved.

  14. The influence of school-based natural mentoring relationships on school attachment and subsequent adolescent risk behaviors.

    Science.gov (United States)

    Black, David S; Grenard, Jerry L; Sussman, Steve; Rohrbach, Louise A

    2010-10-01

    A relatively new area of research suggests that naturally occurring mentoring relationships may influence the development of adolescents by protecting against risk behaviors. Few studies have explored how these relationships function to reduce risk behavior among youth, especially in the school context. Based on previous research and theory, we proposed and tested a mediation model, which hypothesized that school attachment mediated the longitudinal association between school-based natural mentoring relationships and risk behaviors, including eight indicators of substance use and violence. Students (N = 3320) from 65 high schools across eight states completed a self-report questionnaire at baseline and 1-year follow-up. The sample was comprised of youth with an average age of 14.8 years and an almost equal percentage of females (53%) and males from various ethnic backgrounds. Tests for mediation were conducted in Mplus using path analysis with full information maximum likelihood procedures and models adjusted for demographic covariates and baseline level of the dependent variable. Results suggested that natural mentoring relationships had a protective indirect influence on all eight risk behaviors through its positive association on the school attachment mediator. Implications are discussed for strengthening the association between school-based natural mentoring and school attachment to prevent risk behaviors among youth.

  15. Change and Stability in Active and Passive Social Influence Dynamics during Natural Drinking Events: A Longitudinal Measurement-Burst Study

    Science.gov (United States)

    Cullum, Jerry; O’Grady, Megan; Armeli, Stephen; Tennen, Howard

    2011-01-01

    We examined the link between social norms and active social influences occurring during natural social drinking contexts. Across 4 yearly measurement-bursts, college students (N = 523) reported daily for 30-day periods on drinking norms, drinking offers, how many drinks they accepted, and personal drinking levels during social drinking events. In contexts where drinking norms were higher, students were more likely to both receive and comply with drinking offers. These acute social influences were highly stable throughout college, but affected men and women differently across time: Women received more drinking offers than men, especially at the beginning of college and when norms were higher, but men complied with more drinking offers per occasion. These effects were not attributable to between-person differences in social drinking motives or drinking levels, nor to within-person patterns of situation-selection. The present work suggests that context-specific drinking norms catalyze active social influence attempts, and further promote compliance drinking. PMID:22661826

  16. Manganese in the shell of the bivalve Mytilus edulis: Seawater Mn or physiological control?

    Science.gov (United States)

    Freitas, Pedro S.; Clarke, Leon J.; Kennedy, Hilary; Richardson, Christopher A.

    2016-12-01

    Manganese in the shell calcite of marine bivalves has been suggested to reflect ambient seawater Mn concentrations, thus providing a high-resolution archive of past seawater Mn concentrations. However, a quantitative relationship between seawater Mn and shell Mn/Ca ratios, as well as clear understanding of which process(es) control(s) shell Mn/Ca, are still lacking. Blue mussels, Mytilus edulis, were grown in a one-year duration field experiment in the Menai Strait, U.K., to study the relationship between seawater particulate and dissolved Mn2+ concentrations and shell calcite Mn/Ca ratios. Shell Mn/Ca showed a well-defined intra-annual double-peak, with maximum values during early spring and early summer and low values during autumn and winter. Seawater particulate Mn peaked during winter and autumn, with a series of smaller peaks during spring and summer, whereas dissolved Mn2+ exhibited a marked single maximum during late-spring to early-summer, being low during the remainder of the year. Consequently, neither seawater particulate Mn nor dissolved Mn2+ concentrations explain the intra-annual variation of shell Mn/Ca ratios. A physiological control on shell Mn/Ca ratios is evident from the strong similarity and timing of the double-peaked intra-annual variations of Mn/Ca and shell growth rate (SGR), the latter corresponding to periods of increased metabolic activity (as indicated by respiration rate). It is thus likely that in M. edulis SGR influences shell Mn/Ca by altering the concentration or activity of Mn2+ within the extra-pallial fluid (EPF), by changing the flux of Mn into or the proportion of protein bound Mn within the EPF. By linking shell Mn/Ca ratios to the endogenous and environmental factors that determine growth and metabolic activity, this study helps to explain the lack of a consistent relationship between shell Mn/Ca in marine bivalve shell calcite and seawater particulate and dissolved Mn2+ concentrations. The use of Mn content from M. edulis

  17. Biological fate of cobalt-60 released during the corrosion of neutron-activated stanless steel in seawater

    International Nuclear Information System (INIS)

    Young, J.S.

    1982-03-01

    Passing seawater over radioactive Type 347 stainless steel in a sediment/seawater laboratory system and exposing marine animals to this environment provided information on the bioaccumulation of 60 Co from radioactive structural material. Exposure of marine organisms to radioactive corrosion products and directly to radioactive stainless steel in seawater simulated some of the possible conditions which could arise from the deposition of radioactive stainless steel on the ocean floor. Detectable levels of 60 Co in marine animals were not observed on a short term basis (5 weeks). Longterm (13 months) exposure of marine animals in a sediment/seawater system resulted in 60 Co bioaccumulation. The specific activity of 60 Co in the organisms was as much as one million times less than that initially present in the radioactive stainless steel. This was due to the dilution of 60 Co by stable cobalt in the seawater, sediments and organisms. As expected the 60 Co specific activity of the organisms never increased above that of the radioactive source. This is because 60 Co is chemicaly indistinguishable from stable Co. Increasing 60 Co concentration factors with decreasing 60 Co concentrations in the seawater and sediment media coupled with relatively constant 60 Co specific activities suggest a possible homeostatic control of cobalt concentrations in certain marine organisms. The evidence indicates that the marine animals derived more of the accumulated 60 Co from the sediments and interstitial water than from seawater. Cobalt-60 concentration factors were generally found to be lower than published cobalt concentration factors due to the predominantly insoluble nature of the corrosion products. Baseline information is provided on trace element concentrations in deep-sea organisms. Stable Co and twenty other elements were measured in abyssal invertebrates and a fish

  18. Designing Effective Natural Hazards Preparedness Communications: Factors that Influence Perceptions and Action

    Science.gov (United States)

    Wong-Parodi, G.; Fischhoff, B.

    2012-12-01

    Even though most people believe that natural hazards preparation is important for mitigating damage to their homes and basic survival in the aftermath of a disaster, few actually disaster-proof their homes, create plans, or obtain supplies recommended by agencies such as the Federal Emergency Management Agency. Several observational studies suggest that socio-demographic characteristics such as income and psychological characteristics such as self-efficacy affect whether or not an individual takes action to prepare for a natural hazard. These studies, however, only suggest that these characteristics may play a role. There has been little research that systematically investigates how these characteristics play a role in people's perceptions of recommended preparatory activities and decisions to perform them. Therefore, in Study 1, we explore people's perceptions of natural hazards preparedness measures on four dimensions: time, cost, helpfulness, and sense of preparedness. We further investigate if these responses vary by the socio-demographic and psychological characteristics of self-efficacy, knowledge, and income level. In Study 2, we experimentally test whether people's sense of self-efficacy, as it relates to natural hazards, can be manipulated through exposure to an "easy-and-effective" versus a "hard-and-effective" set of preparation measures. Our findings have implications for the design of natural hazards communication materials for the general public.

  19. Ocean Acidification: Investigation and Presentation of the Effects of Elevated Carbon Dioxide Levels on Seawater Chemistry and Calcareous Organisms

    Science.gov (United States)

    Buth, Jeffrey M.

    2016-01-01

    Ocean acidification refers to the process by which seawater absorbs carbon dioxide from the atmosphere, producing aqueous carbonic acid. Acidic conditions increase the solubility of calcium carbonate, threatening corals and other calcareous organisms that depend on it for protective structures. The global nature of ocean acidification and the…

  20. A normalised seawater strontium isotope curve. Possible implications for Neoproterozoic-Cambrian weathering rates and the further oxygenation of the Earth

    International Nuclear Information System (INIS)

    Shields, G.A.

    2007-01-01

    The strontium isotope composition of seawater is strongly influenced on geological time scales by changes in the rates of continental weathering relative to ocean crust alteration. However, the potential of the seawater 87 Sr/ 86 Sr curve to trace globally integrated chemical weathering rates has not been fully realised because ocean 87 Sr/ 86 Sr is also influenced by the isotopic evolution of Sr sources to the ocean. A preliminary attempt is made here to normalise the seawater 87 Sr/ 86 Sr curve to plausible trends in the 87 Sr/ 86 Sr ratios of the three major Sr sources: carbonate dissolution, silicate weathering and submarine hydrothermal exchange. The normalised curve highlights the Neoproterozoic-Phanerozoic transition as a period of exceptionally high continental influence, indicating that this interval was characterised by a transient increase in global weathering rates and/or by the weathering of unusually radiogenic crustal rocks. Close correlation between the normalised 87 Sr/ 86 Sr curve, a published seawater δ 34 S curve and atmospheric pCO 2 models is used here to argue that elevated chemical weathering rates were a major contributing factor to the steep rise in seawater 87 Sr/ 86 Sr from 650 Ma to 500 Ma. Elevated weathering rates during the Neoproterozoic-Cambrian interval led to increased nutrient availability, organic burial and to the further oxygenation of Earth's surface environment. Use of normalised seawater 87 Sr/ 86 Sr curves will, it is hoped, help to improve future geochemical models of Earth System dynamics. (orig.)

  1. Influence of natural or organophilic bentonite for flammable of the poly(ethylene-co-vinyl acetate)

    International Nuclear Information System (INIS)

    Heyder, Eduardo T.; Kloss, Juliana R.; Morita, Reinaldo Y.; Barbosa, Ronilson V.

    2015-01-01

    The manufacture polymeric applied in electrical sector in general use additives which act as flame retardants, for example, some borates, phosphates, and halogenated hydroxides. An alternative material for this purpose frequently reported in the literature because the flame resistance or flame retardancy is organoclay. Thus, the objective of this study is to evaluate the flammability of mixtures of EVA/natural bentonite and EVA/organoclay containing modifier as a species free of quaternary ammonium ions. The natural bentonite and organoclay were characterized by X-ray diffraction and scanning electron microscopy and materials were evaluated by X-ray diffraction and the flammability test. Regarding the combustion rate values, there was a reduction of flame propagation in EVA/natural bentonite (3.0%), showing that in this case the clay without modifier acted as a physical barrier and promoted retardant action of flame. (author)

  2. The influence of the natural environment on the radiological consequences of a nuclear accident

    International Nuclear Information System (INIS)

    Grauby, A.

    1989-01-01

    Much work has been done in the agri-food field on the evaluation of the health implications of a nuclear accident. Much less has been done on environmental dynamics. Research on the behaviour of radioactive deposits from the Chernobyl accident, however, has revealed the importance of natural conditions for the transfer of radionuclides in the environment. In particular, two phases have been observed. In the first, which lasts until a point of equilibrium is reached in the environment, radionuclides follow the water cycle. The second phase unfolds following the incorporation of ruthenium and cesium in soil and sediment. Certain environmental factors (natural ecosystems, relief, etc.) and the different meteorological conditions (climate and season) should be investigated in more detail. Better understanding of the effect of natural conditions could be used to predict, in time and space, any specific risks arising during nuclear accidents whether located near or far [fr

  3. Comparative Inactivation of Murine Norovirus, Human Adenovirus, and Human JC Polyomavirus by Chlorine in Seawater

    Science.gov (United States)

    de Abreu Corrêa, Adriana; Carratala, Anna; Barardi, Celia Regina Monte; Calvo, Miquel; Bofill-Mas, Sílvia

    2012-01-01

    Viruses excreted by humans affect the commercial and recreational use of coastal water. Shellfish produced in contaminated waters have been linked to many episodes and outbreaks of viral gastroenteritis, as well as other food-borne diseases worldwide. The risk can be reduced by appropriate treatment following harvesting and by depuration. The kinetics of inactivation of murine norovirus 1 and human adenovirus 2 in natural and artificial seawater by free available chlorine was studied by quantifying genomic copies (GC) using quantitative PCR and infectious viral particles (PFU). Human JC polyomavirus Mad4 kinetics were evaluated by quantitative PCR. DNase or RNase were used to eliminate free genomes and assess potential viral infectivity when molecular detection was performed. At 30 min of assay, human adenovirus 2 showed 2.6- and 2.7-log10 GC reductions and a 2.3- and 2.4-log10 PFU reductions in natural and artificial seawater, respectively, and infectious viral particles were still observed at the end of the assay. When DNase was used prior to the nucleic acid extraction the kinetic of inactivation obtained by quantitative PCR was statistically equivalent to the one observed by infectivity assays. For murine norovirus 1, 2.5, and 3.5-log10 GC reductions were observed in natural and artificial seawater, respectively, while no viruses remained infectious after 30 min of contact with chlorine. Regarding JC polyomavirus Mad4, 1.5- and 1.1-log10 GC reductions were observed after 30 min of contact time. No infectivity assays were conducted for this virus. The results obtained provide data that might be applicable to seawater used in shellfish depuration. PMID:22773637

  4. Detection of the Light Organ Symbiont, Vibrio fischeri, in Hawaiian Seawater by Using lux Gene Probes.

    Science.gov (United States)

    Lee, K H; Ruby, E G

    1992-03-01

    Symbiotic bacteria that inhabit the light-emitting organ of the Hawaiian squid Euprymna scolopes are distinctive from typical Vibrio fischeri organisms in that they are not visibly luminous when grown in laboratory culture. Therefore, the abundance of these bacteria in seawater samples cannot be estimated simply by identifying them among luminous colonies that arise on nutrient agar plates. Instead, we have used luxR and polymerase chain reaction generated luxA gene probes to identify both luminous and non-visibly luminous V. fischeri colonies by DNA-DNA hybridization. The probes were specific, hybridizing at least 50 to 100 times more strongly to immobilized DNAs from V. fischeri strains than to those of pure cultures of other related species. Thus, even non-visibly luminous V. fischeri colonies could be identified among colonies obtained from natural seawater samples by their probe-positive reaction. Bacteria in seawater samples, obtained either within or distant from squid habitats, were collected on membrane filters and incubated until colonies appeared. The filters were then observed for visibly luminous V. fischeri colonies and hybridized with the lux gene probes to determine the number of total V. fischeri colonies (both luminous and non-visibly luminous). We detected no significant differences in the abundance of luminous V. fischeri CFU in any of the water samples observed (seawater collected from within the natural habitats of the squids. A number of criteria were used to confirm that these probe-positive strains were indistinguishable from symbiotic V. fischeri. Therefore, the luxA and luxR gene probes were species specific and gave a reliable estimate of the number of culturable V. fischeri colonies in natural water samples.

  5. Determination of trace elements in seawater using Mg-scavenger as preconcentration agent, and neutron activation analysis

    International Nuclear Information System (INIS)

    Andersen, B.

    1986-01-01

    In order to determine trace elements in seawater, a preconsentration method based on coprecipitation on Mg(OH) 2 is presented. Different parameters influencing the carrying effects have been investigated using model solutions and radioactive tracers. The deposit and solution are separated by filtration. Filter with deposit is stored in quarts ampules for later determination of trace elements by means of neutron activation analysis

  6. Contribution of Seawater Surfactants to Generated Primary Marine Aerosol Particles

    Science.gov (United States)

    Frossard, A. A.; Gerard, V.; Duplessis, P.; Kinsey, J. D.; Lu, X.; Zhu, Y.; Bisgrove, J.; Maben, J. R.; Long, M. S.; Chang, R.; Beaupre, S. R.; Kieber, D. J.; Keene, W. C.; Noziere, B.; Cohen, R. C.

    2017-12-01

    Surfactants account for minor fractions of total organic carbon in the ocean but may have major impacts on the surface tension of bursting bubbles at the sea surface that drive the production of primary marine aerosol particles (PMA). Surfactants associated with marine aerosol may also significantly reduce the surface tension of water thereby increasing the potential for cloud droplet activation and growth. During September and October 2016, PMA were produced from bursting bubbles in seawater using a high capacity generator at two biologically productive and two oligotrophic stations in the western North Atlantic, as part of a cruise on the R/V Endeavor. Surfactants were extracted from paired PMA and seawater samples, and their ionic compositions, total concentrations, and critical micelle concentrations (CMC) were quantified and compared for the four hydrographic stations. Higher surfactant concentrations were determined in the aerosol produced from biologically productive seawater compared to oligotrophic seawater, and the surfactants extracted from productive seawater were stronger (had lower CMCs) than those in the oligotrophic seawater. Surfactants associated with PMA and seawater in productive regions also varied over diel cycles, whereas those in the oligotrophic regions did not. This work demonstrates a direct link between surfactants in seawater and those in PMA.

  7. Coagulation and ultrafiltration in seawater reverse osmosis pretreatment

    NARCIS (Netherlands)

    Tabatabai, S.A.A.

    2014-01-01

    Seawater desalination is a globally expanding coastal industry with an installed capacity of over 80 million m3/day. Algal blooms pose a challenge to the operation of seawater reverse osmosis (SWRO) membranes and pre-treatment systems due to high concentrations of algal cells and algal organic

  8. Progress in recovery technology for uranium from seawater

    International Nuclear Information System (INIS)

    Sugo, Takanobu; Saito, Kyoichi.

    1994-01-01

    By the facts that the research group in Japan improved the performance of amidoxime resin which is the adsorbent for collecting seawater uranium, proposed the method of mooring floating bodies utilizing sea current and waves as the adsorption system, and further, verified the results of laboratory basic experiment by marine experiment, the technology of collecting seawater uranium has progressed. After the oil crisis, various countries started the research on seawater uranium, but only Japan has continued the systematic study up to now. In this report, the research on seawater uranium collection carried out so far is summarized, and the characteristics of the adsorbent which was synthesized by radiation graft polymerization and the results of the uranium collection test using coastal seawater are reported. In seawater of 1 m 3 , the uranium of 3.3 mg is dissolved in the form of uranyl tricarbonate complex ions. In the total quantity of seawater, the dissolved uranium amounts to about 4.6 billion tons, about 1000 times of the uranium resources on land. The research on seawater uranium collection and the performance of uranium adsorption of synthesized amidoxime fibers are reported. (K.I.)

  9. Biodegradation of phenanthrene in artificial seawater by using free ...

    African Journals Online (AJOL)

    and related aromatic compounds. This paper reports the domestication of strain Sphingomonas sp. GY2B in artificial seawater (AS) and the immobilization of the strain onto rice straw. Results showed that adding 85% artificial seawater had very low impact on the growth and phenanthrene degradation ability of strain GY2B ...

  10. Sulfate was a trace constituent of Archean seawater

    DEFF Research Database (Denmark)

    Crowe, Sean Andrew; Paris, Guillaume; Katsev, Sergei

    2014-01-01

    In the low-oxygen Archean world (>2400 million years ago), seawater sulfate concentrations were much lower than today, yet open questions frustrate the translation of modern measurements of sulfur isotope fractionations into estimates of Archean seawater sulfate concentrations. In the water column...

  11. Modelling of a transmembrane evaporation module for desalination of seawater

    NARCIS (Netherlands)

    Guijt, C.M.; Racz, I.G.; van Heuven, Jan Willem; Reith, T.; de Haan, A.B.

    1999-01-01

    Transmembrane evaporation (often called membrane distillation) carried out in a countercurrent flow module, in which incoming cold seawater is heated by the condensing product water flow, is a promising technology for low-cost seawater desalination. This paper presents a model for preliminary design

  12. Assessing Wild Bee Biodiversity in Cranberry Agroenvironments: Influence of Natural Habitats.

    Science.gov (United States)

    Gervais, Amélie; Fournier, Valérie; Sheffield, Cory S; Chagnon, Madeleine

    2017-08-01

    The conservation of bee populations for pollination in agricultural landscapes has attracted a lot of recent research interest, especially for crop industries undergoing expansion to meet increased production demands. In Canada, much growth has been occurring with commercial cranberry production, a field crop which is largely dependent on bee pollination. Wild bee pollinators could be negatively impacted by losses of natural habitat surrounding cranberry fields to accommodate increased production, but growers have little insight on how to manage their lands to maximize the presence of wild bees. Here, we described a 2-yr study where bee diversity and species composition were investigated to better understand the dynamic between natural habitat and cranberry fields. Bees were sampled using pan-traps and hand netting both within cranberry fields and in one of the three adjacent natural habitat types once a week during the crop flowering period. We found that bee community composition among cranberry fields did not differ based on the respective adjacent habitat type, but fields bordered by meadows were marginally less diverse than fields bordered by forest. As one would expect, field and natural habitat communities differed in terms of species composition and species richness. There was no evidence that one type of natural habitat was more favorable for the bees than another. Future agrobiodiversity studies should simultaneously examine bee diversity comprised in both crop fields and adjacent natural environments to better understand the species dynamics essential to the preservation of pollination services. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  13. The influence of an estimated energy saving due to natural ventilation on the Mexican energy system

    DEFF Research Database (Denmark)

    Oropeza-Perez, Ivan; Østergaard, Poul Alberg

    2014-01-01

    This article shows the impacts of the extensive use of NV (natural ventilation) in the Mexican residential sector on the Mexican energy system. By integrating a thermal-airflow simulation programme with an energy systems analysis model, the impact on the Mexican energy system of replacing air...... conditioning, in particular, with natural ventilation to cool residential buildings is determined. It is shown that when, as in Mexico, there is a relatively simple connection between supply and electricity demand, NV creates savings which could be used to reduce either the fossil-fuel-based generation...

  14. The Influence of Disciplines on the Knowledge of Science: A Study of the Nature of Science

    Directory of Open Access Journals (Sweden)

    B. Akarsu

    2010-06-01

    Full Text Available At least four factors affect pupils’ understanding of the nature of science: teachers’ specialization in different science areas (physics, chemistry, and biology, gender issues, teaching experience in elementary school environments, and the perspectives of acquiring necessary knowledge. This study is the introduction part of a research project which will be initiated soon. Four elementary science teachers participated in the study. The results reveal that participants’ views of the aspects of nature of science are not solely diverged, based on their major disciplines, but there exist significant distinctions according to gender differences.

  15. Analysis of seawater flow through optical fiber

    Science.gov (United States)

    Fernández López, Sheila; Carrera Ramírez, Jesús; Rodriguez Sinobar, Leonor; Benitez, Javier; Rossi, Riccardo; Laresse de Tetto, Antonia

    2015-04-01

    The relation between sea and coastal aquifer is very important to the human populations living in coastal areas. The interrelation involves the submarine ground water discharge of relatively fresh water to the sea and the intrusion of sea water into the aquifer, which impairs the quality of ground water. The main process in seawater intrusion is managed by fluid-density effects which control the displacement of saline water. The underlain salinity acts as the restoring force, while hydrodynamic dispersion and convection lead to a mixing and vertical displacement of the brine. Because of this, a good definition of this saltwater-freshwater interface is needed what is intimately joined to the study of the movements (velocity fields) of fresh and salt water. As it is well known, the flow of salt water studied in seawater intrusion in stationary state, is nearly null or very low. However, in the rest of cases, this flux can be very important, so it is necessary its study to a better comprehension of this process. One possible manner of carry out this analysis is through the data from optical fiber. So, to research the distribution and velocity of the fresh and saltwater in the aquifer, a fiber optic system (OF) has been installed in Argentona (Baix Maresme, Catalonia). The main objective is to obtain the distributed temperature measurements (OF-DTS) and made progress in the interpretation of the dynamic processes of water. For some applications, the optical fiber acts as a passive temperature sensor but in our case, the technique Heated Active Fiber Optic will be used. This is based on the thermal response of the ground as a heat emission source is introduced. The thermal properties of the soil, dependent variables of soil water content, will make a specific temperature distribution around the cable. From the analyzed data we will deduce the velocity field, the real objective of our problem. To simulate this phenomenon and the coupled transport and flow problem

  16. Lawrence Livermore Laboratory concept for uranium recovery from seawater

    International Nuclear Information System (INIS)

    Gregg, D.; Wang, F.

    1980-01-01

    The Lawrence Livermore Laboratory concept for uranium recovery from seawater involves the following process steps: (1) produce activated carbon via a coal gasification plant; (2) contact activated carbon sorbent with seawater using a settling process (no pumping of seawater); (3) vacuum activated carbon from sea floor; (4) gasify or burn activated carbon (further concentrating the uranium in the ash); (5) extract the uranium from the rich ash ore by conventional techniques. The process advantages are: (1) eliminates seawater pumping, the need for an illuent, and the need for a fresh water wash; (2) should result in much lower capital investment and regional process energy. Major process issues are: (1) uranium loading on activated carbon; (2) activated carbon modifications required to improve the sorbtion performance; (3) activated carbon particle size needed to meet system requirements; (4) minimization of sorbent losses when contacted with seawater

  17. Inhibition of Sodium Benzoate on Stainless Steel in Tropical Seawater

    International Nuclear Information System (INIS)

    Seoh, S. Y.; Senin, H. B.; Nik, W. N. Wan; Amin, M. M.

    2007-01-01

    The inhibition of sodium benzoate for stainless steel controlling corrosion was studied in seawater at room temperature. Three sets of sample have been immersed in seawater containing sodium benzoate with the concentrations of 0.3M, 0.6M and 1.0M respectively. One set of sample has been immersed in seawater without adding any sodium benzoate. It was found that the highest corrosion rate was observed for the stainless steel with no inhibitor was added to the seawater. As the concentration of sodium benzoate being increased, the corrosion rate is decreases. Results show that by the addition of 1.0M of sodium benzoate in seawater samples, it giving ≥ 90% efficiencies

  18. Influences of Teleological and Lamarckian Thinking on Student Understanding of Natural Selection

    Science.gov (United States)

    Stover, Shawn K.; Mabry, Michelle L.

    2007-01-01

    Previous research has demonstrated creationist, Lamarckian, and teleological reasoning in high school and college students. These lines of thinking conflict with the Darwinian notion of natural selection, which serves as the primary catalyst for biological evolution. The current study assessed evolutionary conceptions in non-science majors,…

  19. Stand structure influences nekton community composition and provides protection from natural disturbance in Micronesian mangroves

    Science.gov (United States)

    Richard A. MacKenzie; Nicole Cormier

    2012-01-01

    Structurally complex mangrove roots are thought to provide foraging habitat, predation refugia, and typhoon protection for resident fish, shrimp, and crabs. The spatially compact nature of Micronesian mangroves results in model ecosystems to test these ideas. Tidal creek nekton assemblages were compared among mangrove forests impacted by Typhoon Sudal and differing in...

  20. Heat and mass transfer during cooling and storage of agricultural products as influenced by natural convection

    NARCIS (Netherlands)

    Beukema, K.J.

    1980-01-01

    Three different models of bulk-stored agricultural products with air flow through the bulk, predicting the temperature profiles or the velocity of natural convection, are developed. The temperature distribution in a cylindrical container with insulated walls and open top and bottom, filled

  1. Natural control in cabbage root fly populations and influence of chemicals

    NARCIS (Netherlands)

    Abu Yaman, I.K.

    1960-01-01

    To facilitate studies on the natural and chemical control of Hylemya (Erioischia) brassicae (Bch.) in Holland, the bionomics and abundance of the Anthomyiid were investigated in 1959-9 in fields in which cauliflower was grown. The numbers of eggs and larvae were estimated by scrutiny of

  2. Influence of wind direction and urban surroundings on natural ventilation of a large football stadium

    NARCIS (Netherlands)

    Hooff, van T.A.J.; Blocken, B.J.E.

    2011-01-01

    In this paper, CFD simulations of the natural ventilation of a large semi-enclosed stadium in the Netherlands during summer conditions are described. The simulations are performed to assess the air exchange rate for eight wind directions. The CFD model consists of both the complex stadium geometry

  3. The sedimentary dynamics in natural and human-influenced delta channel belts

    NARCIS (Netherlands)

    Hobo, N.

    2015-01-01

    This study investigates the increased anthropogenic influence on the within-channel belt sedimentary dynamics in the Rhine delta. To make this investigation, the sedimentary dynamics within the life-cycle of a single channel belt were reconstructed for three key periods of increasing human impact,

  4. FOUNDATION AND DESCRIPTION OF INFORMATIONAL AND PSYCHOLOGICAL DESTRUCTIVE NATURE INFLUENCES DYNAMICS MODEL IN SOCIAL NETWORKS

    Directory of Open Access Journals (Sweden)

    V. A. Minaev

    2016-10-01

    Full Text Available The article provides a definition of information and psychological technologies and the main channels of information and psychological influences (IPI on social groups. A detailed analysis of the modeling human behavior experience, including the work of Soviet, Russian and foreign scientists is given. It is concluded that mathematical models of information-psychological dynamics influence on the current stage of psychological science development perspective only in relation to mass consciousness. Due to the complexity and poor knowledge of processes occurring in the human psyche and determined his personal peculiarities, the creation of adequate mathematical models of IPI in the individual consciousness is impossible, but for the expert prediction and assessment of the IPI dynamics on a particular member of a social group should use existing proven scientific tests and technique. It has been shown that a significant improvement in the predictability of mathematical models expected in the transition to a dynamic model in the state space. Given verbal and formal description of the model, leading to a form of non-linear differential equation describing the diffusion of innovations. The models take into account of the mass media influence on society, interpersonal information exchange, the effect of forgetting influence. It was emphasized that similar modified mathematical model has given good results in its application to the description of the electoral processes in Russia and spread of ideas of the "Arabian Spring" through social networks.

  5. The oral microbiome of denture wearers is influenced by levels of natural dentition

    NARCIS (Netherlands)

    O'Donnell, L.E.; Robertson, D.; Nile, C.J.; Cross, L.J.; Riggio, M.; Sherriff, A.; Bradshaw, D.; Lambert, M.; Malcolm, J.; Buijs, M.J.; Zaura, E.; Crielaard, W.; Brandt, B.W.; Ramage, G.

    2015-01-01

    Objectives The composition of dental plaque has been well defined, whereas currently there is limited understanding of the composition of denture plaque and how it directly influences denture related stomatitis (DS). The aims of this study were to compare the microbiomes of denture wearers, and to

  6. The Changing Nature of Power, Control, and Influence in Sibling Relationships

    Science.gov (United States)

    Campione-Barr, Nicole

    2017-01-01

    The sibling relationship is unique in that it transforms across development from hierarchical in early childhood, to egalitarian by adulthood. The present article reviews the previous theorizing and research literature regarding how and why power, control, and therefore sibling influence, change over the course of the first couple of decades, and…

  7. Determination of Uranium and Thorium in Drinking and Seawater

    International Nuclear Information System (INIS)

    Rozmaric Macefat, M.; Gojmerac Ivsic, A.; Grahek, Z.; Barisic, D.

    2008-01-01

    Uranium and thorium are the first members of natural radioactive chain which makes their determination in natural materials interesting from geochemical and radioecological aspect. They are quantitatively determined as elements by spectrophotometric method and/or their radioisotopes by alpha spectrometry and ICP-MS. It is necessary to develop inexpensive, rapid and sensitive methods for the routine researches because of continuous monitoring of the radioactivity level. Development of a new method for the isolation of uranium and thorium from liquid samples and subsequent spectrophotometric determination is described in this paper. It is possible to isolate uranium and thorium from drinking and seawater using extraction chromatography or ion exchange chromatography. Uranium and thorium can be strongly bound on the TRU extraction chromatographic resin from 3 mol dm -3 HNO 3 (chemical recovery is 100 percent) and separated from other interfering elements (sodium, potassium, calcium, strontium etc). Their mutual separation is possible by using anion exchanger Amberlite CG-400 (NO 3 - form). From alcoholic solutions of nitric acid thorium can be strongly bound on the anion exchanger while uranium is much more weakly bound which enables its separation from thorium. After the separation, uranium and thorium are determined by spectrophotometric method with arsenazo III at 652 nm and 662 nm respectively. Developed method enables selection of the optimal mode of isolation for the given purposes.(author)

  8. Corrosion and protection of aluminum alloys in seawater

    Energy Technology Data Exchange (ETDEWEB)

    Nisancioglu Kemal [Department of Materials Technology, Norwegian University of Science and Technology, N-7491 Trondheim (Norway)

    2004-07-01

    The paper deals with pitting and uniform corrosion and effectiveness of cathodic protection in reducing these corrosion forms. In stagnant waters or presence of low flow rates, pitting may occur. However, pitting corrosion, driven by the Fe-rich cathodic intermetallic compounds, is often of superficial nature. The pits tend to passivate as a result of etching or passivation of the intermetallics with time. Cathodic protection is an effective way of preventing pitting. It also requires low current densities since the cathodic area, defined by the Fe-rich intermetallics, is small in contrast to steel, which is uniformly accessible to the cathodic reaction. Although thermodynamic calculations suggest possible instability of the oxide in slightly alkaline solutions, such as seawater, protective nature of the oxide in practice is attributed to the presence of alloying elements such as Mg and Mn. Thus, the passivity of both the aluminum matrix alloy (the anode) and the intermetallics (cathodes) have to be considered in evaluating the corrosion and protection of aluminum alloys. With increasing flow rate, the possibility of pitting corrosion reduces with increase in the rate of uniform corrosion, which is controlled by the flow dependent chemical dissolution of the oxide. Cathodic protection does not stop this phenomenon, and coatings have to be used. (authors)

  9. Determining subnanomolar iron concentrations in oceanic seawater using a siderophore-modified film analyzed by infrared spectroscopy.

    Science.gov (United States)

    Roy, Eric G; Jiang, Cuihong; Wells, Mark L; Tripp, Carl

    2008-06-15

    Iron is a bioactive trace element in seawater that regulates photosynthetic carbon dioxide drawdown and export from surface waters by phytoplankton in upward of 40% of the world's oceans. While autonomous sensor arrays are beginning to provide high-resolution data on temporal and spatial scales for some key oceanographic parameters, current analytical methods for iron are not amenable to autonomous platforms because of the need for user involvement and wet chemistry-based approaches. As a result, very large gaps remain in our understanding of iron distribution and chemistry in seawater. Here we present a straightforward nanostructure-based method to measure dissolved iron in natural seawater. The device comprises an iron-specific chelating biomolecule, desferrioxamine B (DFB), covalently immobilized on a mesoporous silica film. Changes in infrared spectral signatures of the immobilized DFB upon Fe(III) complexation provide an accurate and precise measure of iron on the surface of a chip exposed to seawater. The current system has a detection limit of approximately 50 pM for a 1-L sample at pH 1.7 and was used to measure dissolved iron in subarctic Pacific waters without interference from other elements in seawater. This technology provides a major step toward obtaining accurate iron measurements on autonomous research platforms.

  10. Seawater cultivation of freshwater cyanobacterium Synechocystis sp. PCC 6803 drastically alters amino acid composition and glycogen metabolism

    Directory of Open Access Journals (Sweden)

    Hiroko eIijima

    2015-04-01

    Full Text Available Water use assessment is important for bioproduction using cyanobacteria. For eco-friendly reasons, seawater should preferably be used for cyanobacteria cultivation instead of freshwater. In this study, we demonstrated that the freshwater unicellular cyanobacterium Synechocystis sp. PCC 6803 could be grown in a medium based on seawater. The Synechocystis wild-type strain grew well in an artificial seawater (ASW medium supplemented with nitrogen and phosphorus sources. The addition of HEPES buffer improved cell growth overall, although the growth in ASW medium was inferior to that in the synthetic BG-11 medium. The levels of proteins involved in sugar metabolism changed depending on the culture conditions. The biosynthesis of several amino acids including aspartate, glutamine, glycine, proline, ornithine, and lysine, was highly up-regulated by cultivation in ASW. Two types of natural seawater (NSW were also made available for the cultivation of Synechocystis cells, with supplementation of both nitrogen and phosphorus sources. These results revealed the potential use of seawater for the cultivation of freshwater cyanobacteria, which would help to reduce freshwater consumption during biorefinery using cyanobacteria.

  11. An Earth-Abundant Catalyst-Based Seawater Photoelectrolysis System with 17.9% Solar-to-Hydrogen Efficiency.

    Science.gov (United States)

    Hsu, Shao-Hui; Miao, Jianwei; Zhang, Liping; Gao, Jiajian; Wang, Hongming; Tao, Huabing; Hung, Sung-Fu; Vasileff, Anthony; Qiao, Shi Zhang; Liu, Bin

    2018-05-01

    The implementation of water splitting systems, powered by sustainable energy resources, appears to be an attractive strategy for producing high-purity H 2 in the absence of the release of carbon dioxide (CO 2 ). However, the high cost, impractical operating conditions, and unsatisfactory efficiency and stability of conventional methods restrain their large-scale development. Seawater covers 70% of the Earth's surface and is one of the most abundant natural resources on the planet. New research is looking into the possibility of using seawater to produce hydrogen through electrolysis and will provide remarkable insight into sustainable H 2 production, if successful. Here, guided by density functional theory (DFT) calculations to predict the selectivity of gas-evolving catalysts, a seawater-splitting device equipped with affordable state-of-the-art electrocatalysts composed of earth-abundant elements (Fe, Co, Ni, and Mo) is demonstrated. This device shows excellent durability and specific selectivity toward the oxygen evolution reaction in seawater with near 100% Faradaic efficiency for the production of H 2 and O 2 . Powered by a single commercial III-V triple-junction photovoltaic cell, the integrated system achieves spontaneous and efficient generation of high-purity H 2 and O 2 from seawater at neutral pH with a remarkable 17.9% solar-to-hydrogen efficiency. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Application of micro-solid-phase extraction for the on-site extraction of heterocyclic aromatic amines in seawater.

    Science.gov (United States)

    Basheer, Chanbasha

    2018-04-01

    An efficient on-site extraction technique to determine carcinogenic heterocyclic aromatic amines in seawater has been reported. A micro-solid-phase extraction device placed inside a portable battery-operated pump was used for the on-site extraction of seawater samples. Before on-site applications, parameters that influence the extraction efficiency (extraction time, type of sorbent materials, suitable desorption solvent, desorption time, and sample volume) were investigated and optimized in the laboratory. The developed method was then used for the on-site sampling of heterocyclic aromatic amines determination in seawater samples close to distillation plant. Once the on-site extraction completed, the small extraction device with the analytes was brought back to the laboratory for analysis using high-performance liquid chromatography with fluorescence detection. Based on the optimized conditions, the calibration curves were linear over the concentration range of 0.05-20 μg/L with correlation coefficients up to 0.996. The limits of detection were 0.004-0.026 μg/L, and the reproducibility values were between 1.3 and 7.5%. To evaluate the extraction efficiency, a comparison was made with conventional solid-phase extraction and it was applied to various fortified real seawater samples. The average relative recoveries obtained from the spiked seawater samples varied in the range 79.9-95.2%. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Genome-wide transcriptional responses of Alteromonas naphthalenivorans SN2 to contaminated seawater and marine tidal flat sediment.

    Science.gov (United States)

    Jin, Hyun Mi; Jeong, Hye Im; Kim, Kyung Hyun; Hahn, Yoonsoo; Madsen, Eugene L; Jeon, Che Ok

    2016-02-18

    A genome-wide transcriptional analysis of Alteromonas naphthalenivorans SN2 was performed to investigate its ecophysiological behavior in contaminated tidal flats and seawater. The experimental design mimicked these habitats that either added naphthalene or pyruvate; tidal flat-naphthalene (TF-N), tidal flat-pyruvate (TF-P), seawater-naphthalene (SW-N), and seawater-pyruvate (SW-P). The transcriptional profiles clustered by habitat (TF-N/TF-P and SW-N/SW-P), rather than carbon source, suggesting that the former may exert a greater influence on genome-wide expression in strain SN2 than the latter. Metabolic mapping of cDNA reads from strain SN2 based on KEGG pathway showed that metabolic and regulatory genes associated with energy metabolism, translation, and cell motility were highly expressed in all four test conditions, probably highlighting the copiotrophic properties of strain SN2 as an opportunistic marine r-strategist. Differential gene expression analysis revealed that strain SN2 displayed specific cellular responses to environmental variables (tidal flat, seawater, naphthalene, and pyruvate) and exhibited certain ecological fitness traits -- its notable PAH degradation capability in seasonally cold tidal flat might be reflected in elevated expression of stress response and chaperone proteins, while fast growth in nitrogen-deficient and aerobic seawater probably correlated with high expression of glutamine synthetase, enzymes utilizing nitrite/nitrate, and those involved in the removal of reactive oxygen species.

  14. Desorption of radioactive cesium by seawater from the suspended particles in river water.

    Science.gov (United States)

    Onodera, Masaki; Kirishima, Akira; Nagao, Seiya; Takamiya, Kouichi; Ohtsuki, Tsutomu; Akiyama, Daisuke; Sato, Nobuaki

    2017-10-01

    In 2011, the accident at the Fukushima-Daiichi nuclear power plant dispersed radioactive cesium throughout the environment, contaminating the land, rivers, and sea. Suspended particles containing clay minerals are the transportation medium for radioactive cesium from rivers to the ocean because cesium is strongly adsorbed between the layers of clay minerals, forming inner sphere complexes. In this study, the adsorption and desorption behaviors of radioactive cesium from suspended clay particles in river water have been investigated. The radioactive cesium adsorption and desorption experiments were performed with two kinds of suspended particulate using a batch method with 137 Cs tracers. In the cesium adsorption treatment performed before the desorption experiments, simulated river water having a total cesium concentration ([ 133+137 Cs + ] total ) of 1.3 nM (10 -9  mol/L) was used. The desorption experiments were mainly conducted at a solid-to-liquid ratio of 0.17 g/L. The desorption agents were natural seawater collected at 10 km north of the Fukushima-Daiichi nuclear power plant, artificial seawater, solutions of NaCl, KCl, NH 4 Cl, and 133 CsCl, and ultrapure water. The desorption behavior, which depends on the preloaded cesium concentration in the suspended particles, was also investigated. Based on the cesium desorption experiments using suspended particles, which contained about 1000 ng/g loaded cesium, the order of cesium desorption ratios for each desorption agent was determined as 1 M NaCl (80%) > 470 mM NaCl (65%) > 1 M KCl (30%) ≈ seawater (natural seawater and Daigo artificial seawater) > 1 M NH 4 Cl (20%) > 1 M 133 CsCl (15%) ≫ ultrapure water (2%). Moreover, an interesting result was obtained: The desorption ratio in the 470 mM NaCl solution was much higher than that in seawater, even though the Na + concentrations were identical. These results indicate that the cesium desorption mechanism is not a simple ion exchange reaction

  15. SOLUBILITIES AND PHYSICAL PROPERTIES OF SATURATED SOLUTIONS IN THE COPPER SULFATE + SULFURIC ACID + SEAWATER SYSTEM AT DIFFERENT TEMPERATURES

    Directory of Open Access Journals (Sweden)

    F. J. Justel

    2015-09-01

    Full Text Available AbstractIn Chile, the most important economic activity is mining, concentrated in the north of the country. This is a desert region with limited water resources; therefore, the mining sector requires research and identification of alternative sources of water. One alternative is seawater, which can be a substitute of the limited fresh water resources in the region. This work determines the influence of seawater on the solid-liquid equilibrium for acid solutions of copper sulfate at different temperatures (293.15 to 318.15 K, and its effect on physical properties (density, viscosity, and solubility. Knowledge of these properties and solubility data are useful in the leaching process and in the design of copper sulfate pentahydrate crystallization plants from the leaching process using seawater by means of the addition of sulfuric acid.

  16. Post-Mesozoic Rapid Increase of Seawater Mg/Ca due to Enhanced Mantle-Seawater Interaction

    Science.gov (United States)

    Ligi, Marco; Bonatti, Enrico; Cuffaro, Marco; Brunelli, Daniele

    2013-01-01

    The seawater Mg/Ca ratio increased significantly from ~ 80 Ma to present, as suggested by studies of carbonate veins in oceanic basalts and of fluid inclusions in halite. We show here that reactions of mantle-derived peridotites with seawater along slow spreading mid-ocean ridges contributed to the post-Cretaceous Mg/Ca increase. These reactions can release to modern seawater up to 20% of the yearly Mg river input. However, no significant peridotite-seawater interaction and Mg-release to the ocean occur in fast spreading, East Pacific Rise-type ridges. The Mesozoic Pangean superocean implies a hot fast spreading ridge system. This prevented peridotite-seawater interaction and Mg release to the Mesozoic ocean, but favored hydrothermal Mg capture and Ca release by the basaltic crust, resulting in a low seawater Mg/Ca ratio. Continent dispersal and development of slow spreading ridges allowed Mg release to the ocean by peridotite-seawater reactions, contributing to the increase of the Mg/Ca ratio of post-Mesozoic seawater. PMID:24067442

  17. Evaluation of seawater corrosion of SSCs

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-08-15

    In the unit 1 to unit 4 of the Fukushima Daiichi Nuclear Power Plant, seawater was injected in reactor pressure vessels and spent fuel pools in order to cool nuclear fuel after the disaster of the 2011 off the Pacific coast of Tohoku Earthquake and Tsunami. In fiscal 2012, overall plan of this project has been developed in consideration of corrosion events that might be assumed reactor pressure vessels, spent fuel pools and primary containment vessels of Fukushima Daiichi Nuclear Power Station that was designated to be as the 'Specified Nuclear Power Facilities'. In this project, crevice corrosion susceptibility of stainless steel, galvanic corrosion of aluminum alloy, and uniform corrosion of carbon steel piping will be evaluated. (author)

  18. Energy Implications of Seawater Desalination (Invited)

    Science.gov (United States)

    Cooley, H.; Heberger, M. G.

    2013-12-01

    Freshwater has traditionally come from rivers, lakes, streams, and groundwater aquifers. As demand increases and climate change alters the location and timing of water supply, these traditional sources are becoming unavailable, more difficult, or increasingly expensive to develop. As a result, many communities are switching to alternative sources of water. Interest in pursuing seawater desalination is high in many coastal communities. In California, for example, 17 plants are proposed for development along the California coast and two in Mexico. Water managers are pursing desalination because is a local supply that can help diversify the water supply portfolio. Additionally, it is a reliable supply, which can be especially valuable during a drought. But removing the salt from seawater is an energy-intensive process that consumes more energy per gallon than most other water supply and treatment options. These energy requirements are key factors that will impact the extent and success of desalination in California. Energy requirements for seawater desalination average about 4.0 kWh per cubic meter (m3) of water produced. By comparison, the least energy-intensive options of local sources of groundwater and surface water require 0 - 0.90 kWh per m3; wastewater reuse, depending on treatment levels, may require from 0.26 - 2.2 kWh per m3. Beyond the electricity required for the desalination facility itself, producing any new source of water, including through desalination, increases the amount of energy required to deliver and use the water produced as well as collect, treat, and dispose of the wastewater generated. Energy is the largest single variable cost for a desalination plant, varying from one-third to more than one-half the cost of produced water. Building a desalination plant may reduce a water utility's exposure to water reliability risks at the added expense of an increase in exposure to energy price risk. In dependent on hydropower, electricity prices tend to

  19. Energy balance for uranium recovery from seawater

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, E.; Lindner, H. [The University of Texas, 1 University Station C2200, Austin, TX 78712 (United States)

    2013-07-01

    The energy return on investment (EROI) of an energy resource is the ratio of the energy it ultimately produces to the energy used to recover it. EROI is a key viability measure for a new recovery technology, particularly in its early stages of development when financial cost assessment would be premature or highly uncertain. This paper estimates the EROI of uranium recovery from seawater via a braid adsorbent technology. In this paper, the energy cost of obtaining uranium from seawater is assessed by breaking the production chain into three processes: adsorbent production, adsorbent deployment and mooring, and uranium elution and purification. Both direct and embodied energy inputs are considered. Direct energy is the energy used by the processes themselves, while embodied energy is used to fabricate their material, equipment or chemical inputs. If the uranium is used in a once-through fuel cycle, the braid adsorbent technology EROI ranges from 12 to 27, depending on still-uncertain performance and system design parameters. It is highly sensitive to the adsorbent capacity in grams of U captured per kg of adsorbent as well as to potential economies in chemical use. This compares to an EROI of ca. 300 for contemporary terrestrial mining. It is important to note that these figures only consider the mineral extraction step in the fuel cycle. At a reference performance level of 2.76 g U recovered per kg adsorbent immersed, the largest energy consumers are the chemicals used in adsorbent production (63%), anchor chain mooring system fabrication and operations (17%), and unit processes in the adsorbent production step (12%). (authors)

  20. Seawater pumping as an electricity storage solution for photovoltaic energy systems

    International Nuclear Information System (INIS)

    Manfrida, Giampaolo; Secchi, Riccardo

    2014-01-01

    The stochastic nature of several renewable energy sources has raised the problem of designing and building storage facilities, which can help the electricity grid to sustain larger and larger contribution of renewable energy. Seawater pumped electricity storage is proposed as a good option for PV (Photovoltaic) or solar thermal power plants, located in suitable places close to the coast line. Solar radiation has a natural daily cycle, and storage reservoirs of limited capacity can substantially reduce the load to the electricity grid. Different modes of pump operation (fixed or variable speed) are considered, the preliminary sizing of the PV field and seawater reservoir is performed, and the results are comparatively assessed over a year-long simulated operation. The results show that PV pumped storage, even if not profitable in the present situation of the renewable energy Italian electricity market, is effective in decreasing the load on the transmission grid, and would possibly be attractive in the future, also in the light of developing off-grid applications. - Highlights: • A grid-connected seawater pumping system using photovoltaic power is proposed and its performance analyzed. • Year-round simulations are run with different sizes of photovoltaic field and reservoir. • An analysis is run about the profitability of the storage system, examining performance indexes and the cost of plant. • The system proposed appears near to attract the interest of the market

  1. Standard practice for exposing and evaluating metals and alloys in surface seawater

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2000-01-01

    1.1 This practice covers conditions for the exposure of metals, alloys, and other materials in natural surface seawater such as those typically found in bays, harbors, channels, and so forth, as contrasted with deep ocean testing. This practice covers full immersion, tidal zone and related splash, and spray zone exposures. 1.2 This practice sets forth general procedures that should be followed in conducting seawater exposure tests so that meaningful comparisons may be made from one location to another. 1.3 This practice identifies recommended procedures for evaluating the effects of natural surface seawater on the materials exposed. 1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regula...

  2. EQCM Study of Influence of Anion Nature on Electrochemical Reduction of Bismuth Sulfide in Nickel Plating Solution

    Directory of Open Access Journals (Sweden)

    Loreta TAMAŠAUSKAITĖ-TAMAŠIŪNAITĖ

    2011-03-01

    Full Text Available The influence of anion nature on the reduction of bismuth sulfide film deposited on gold using the successive ionic layer adsorption and reaction method in solutions containing Ni2+ ions has been investigated by electrochemical quartz crystal microbalance combined with cyclic voltammetry and X-ray photoelectron spectroscopy. It has been determined that the reduction of bismuth sulfide film in the nickel plating solution depends on the anion nature: larger cathodic current and mass changes (Dƒ are observed in the solution containing acetate anion as compared to those in the solution containing sulfate anion. As the reduction of bismuth sulfide film in the background solutions depends on the nature of anion, it influences the cathodic reduction of Ni2+ ions prior to OPD of Ni. A greater current and mass change (Dƒ is conditioned by simultaneously occurring reduction of bismuth sulfide film when the film is reduced in the acetate nickel plating electrolyte in contrast to that in the sulfate one.http://dx.doi.org/10.5755/j01.ms.17.1.244

  3. Genetic composition of social groups influences male aggressive behaviour and fitness in natural genotypes of Drosophila melanogaster.

    Science.gov (United States)

    Saltz, Julia B

    2013-11-22

    Indirect genetic effects (IGEs) describe how an individual's behaviour-which is influenced by his or her genotype-can affect the behaviours of interacting individuals. IGE research has focused on dyads. However, insights from social networks research, and other studies of group behaviour, suggest that dyadic interactions are affected by the behaviour of other individuals in the group. To extend IGE inferences to groups of three or more, IGEs must be considered from a group perspective. Here, I introduce the 'focal interaction' approach to study IGEs in groups. I illustrate the utility of this approach by studying aggression among natural genotypes of Drosophila melanogaster. I chose two natural genotypes as 'focal interactants': the behavioural interaction between them was the 'focal interaction'. One male from each focal interactant genotype was present in every group, and I varied the genotype of the third male-the 'treatment male'. Genetic variation in the treatment male's aggressive behaviour influenced the focal interaction, demonstrating that IGEs in groups are not a straightforward extension of IGEs measured in dyads. Further, the focal interaction influenced male mating success, illustrating the role of IGEs in behavioural evolution. These results represent the first manipulative evidence for IGEs at the group level.

  4. Numerical Study of Natural Supercavitation Influenced by Rheological Properties of Turbulent Drag-Reducing Additives

    Directory of Open Access Journals (Sweden)

    Chen-Xing Jiang

    2014-08-01

    Full Text Available Natural supercavitations in water and turbulent drag-reducing solution were numerically simulated using unsteady Reynolds averaged Navier-Stokes (RANS scheme with mixture-multiphase model. The Cross viscosity equation was adopted to represent the fluid property of aqueous solution of drag-reducing additives. The characteristics of natural supercavity configuration and overall resistance of the navigating body were presented, respectively. The numerical simulation results indicated that, at the same cavitation number, the length and diameter of supercavity in drag-reducing solution are larger than those in water, and the drag coefficient of navigating body in solution is smaller than that in water; the surface tension plays an important role in incepting and maintaining the cavity. Turbulent drag-reducing additives have the potential in enhancement of supercavitation, drag reduction, and decrease of turbulent vortex structures. Numerical simulation results are consistent with the available experimental data.

  5. Effects of seawater pCO2 and temperature on calcification and productivity in the coral genus Porites spp.: an exploration of potential interaction mechanisms

    Science.gov (United States)

    Cole, C.; Finch, A. A.; Hintz, C.; Hintz, K.; Allison, N.

    2018-06-01

    Understanding how rising seawater pCO2 and temperatures impact coral aragonite accretion is essential for predicting the future of reef ecosystems. Here, we report 2 long-term (10-11 month) studies assessing the effects of temperature (25 and 28 °C) and both high and low seawater pCO2 (180-750 μatm) on the calcification, photosynthesis and respiration of individual massive Porites spp. genotypes. Calcification rates were highly variable between genotypes, but high seawater pCO2 reduced calcification significantly in 4 of 7 genotypes cultured at 25 °C but in only 1 of 4 genotypes cultured at 28 °C. Increasing seawater temperature enhanced calcification in almost all corals, but the magnitude of this effect was seawater pCO2 dependent. The 3 °C temperature increase enhanced calcification rate on average by 3% at 180 μatm, by 35% at 260 μatm and by > 300% at 750 μatm. The rate increase at high seawater pCO2 exceeds that observed in inorganic aragonites. Responses of gross/net photosynthesis and respiration to temperature and seawater pCO2 varied between genotypes, but rates of all these processes were reduced at the higher seawater temperature. Increases in seawater temperature, below the thermal stress threshold, may mitigate against ocean acidification in this coral genus, but this moderation is not mediated by an increase in net photosynthesis. The response of coral calcification to temperature cannot be explained by symbiont productivity or by thermodynamic and kinetic influences on aragonite formation.

  6. High Precision Seawater Sr/Ca Measurements in the Florida Keys by Inductively Coupled Plasma Atomic Emission Spectrometry: Analytical Method and Implications for Coral Paleothermometry

    Science.gov (United States)

    Khare, A.; Kilbourne, K. H.; Schijf, J.

    2017-12-01

    Standard methods of reconstructing past sea surface temperatures (SSTs) with coral skeletal Sr/Ca ratios assume the seawater Sr/Ca ratio is constant. However, there is little data to support this assumption, in part because analytical techniques capable of determining seawater Sr/Ca with sufficient accuracy and precision are expensive and time consuming. We demonstrate a method to measure seawater Sr/Ca using inductively coupled plasma atomic emission spectrometry where we employ an intensity ratio calibration routine that reduces the self- matrix effects of calcium and cancels out the matrix effects that are common to both calcium and strontium. A seawater standard solution cross-calibrated with multiple instruments is used to correct for long-term instrument drift and any remnant matrix effects. The resulting method produces accurate seawater Sr/Ca determinations rapidly, inexpensively, and with a precision better than 0.2%. This method will make it easier for coral paleoclimatologists to quantify potentially problematic fluctuations in seawater Sr/Ca at their study locations. We apply our method to test for variability in surface seawater Sr/Ca along the Florida Keys Reef Tract. We are collecting winter and summer samples for two years in a grid with eleven nearshore to offshore transects across the reef, as well as continuous samples collected by osmotic pumps at four locations adjacent to our grid. Our initial analysis of the grid samples indicates a trend of decreasing Sr/Ca values offshore potentially due to a decreasing groundwater influence. The values differ by as much as 0.05 mmol/mol which could lead to an error of 1°C in mean SST reconstructions. Future work involves continued sampling in the Florida Keys to test for seasonal and interannual variability in seawater Sr/Ca, as well as collecting data from small reefs in the Virgin Islands to test the stability of seawater Sr/Ca under different geologic, hydrologic and hydrographic environments.

  7. Enhanced Indirect Somatic Embryogenesis of Date Palm Using Low Levels of Seawater.

    Science.gov (United States)

    Taha, Rania A

    2017-01-01

    Date palm tolerates salinity, drought, and high temperatures. Arid and semiarid zones, especially the Middle East region, need a huge number of date palms for cultivation. To meet this demand, tissue culture techniques have great potential for mass production of plantlets, especially using the indirect embryogenesis technique; any improvement of these techniques is a worthy objective. Low levels of salinity can enhance growth and development of tolerant plants. A low level of seawater, a natural source of salinity, reduces the time required for micropropagation processes of date palm cv. Malkaby when added to MS medium. Medium containing seawater at 500 ppm total dissolved solid (TDS) (12.2 mL/L) improves callus proliferation, whereas 1500 ppm (36.59 mL/L) enhances plant regeneration including multiplication of secondary embryos, embryo germination, and rooting.

  8. Pre-treatment of desalination feed seawater by Jordanian Tripoli, Pozzolana and Feldspar: batch experiments

    Directory of Open Access Journals (Sweden)

    AIMAN E. AL-RAWAJFEH

    2011-06-01

    Full Text Available In this research, composites of layered double hydroxide (LDH with three Jordanian natural raw materials: Tripoli (T, Pozzolana (P and Feldspar (F were prepared by co-precipitation and have been used for feed seawater pre-treatment. The data reveals that percent adsorption decreased with increase in initial concentration, but the actual amount of adsorbed ions per unit mass of LDH/T-P-F increased with increase in metal ion concentrations. The values of ΔG were negative and within 21 to 26 kJ/mol, while the values of and ΔS were positive, with ΔH within the range of 0.1 to 25 kJ/mol. The values of ΔH, ΔS and ΔG indicate the favorability of physisorption and show that the LDH/T-P-F composites have a considerable potential as adsorbents for the removal of ions from seawater.

  9. Anthropogenic and natural influence on disease prevalence at the humanlivestockwildlife interface in the Serengeti ecosystem, Tanzania

    OpenAIRE

    Fyumagwa, Robert Dominikus

    2012-01-01

    Anthropogenic activities in ecosystems interfere with natural processes and cause habitat fragmentation and loss. Habitat fragmentation and loss restrict wildlife movement between populations consequently reducing the gene flow and genetic diversity. Increased human encroachment on wildlife habitat compromises immunity and disturbs host-pathogen relationships resulting in disease outbreaks in naïve populations. Tick-borne and infectious diseases are considered a major threat to the health of ...

  10. Influence of the altitude on the burning velocity of the natural gas

    International Nuclear Information System (INIS)

    Arrieta, Andres Amell; Garcia Posada, Jorge Mario; Quilindo Valencia, Arvey; Henao Vallejo, Diego Alberto

    2004-01-01

    By the increasing use of natural gas in cities of Latin America located to high altitude, is necessary to study the effect of the altitude on the combustion, for example the burning velocity. This work is an experimental study of as it changes to the burning velocity with the altitude, being made test in sites with altitude of 40, 550, 1.020, 1.550, 2.040 and 2.550 meters. The result was that the variations are slight

  11. Influence of Natural, Synthetic Polymers and Fillers on sustained release matrix tablets of Pregabalin

    OpenAIRE

    Vijaya Durga. K; Ashok Kumar. P; Suresh V Kulkarni

    2013-01-01

    The objective of the present study was to develop sustained release matrix tablets of Pregabalin for the treatment of neuropathic pain and epilepsy. The tablets were prepared by wet granulation and formulated using drug with Hydrophilic, hydrophobic, synthetic, natural polymers and 4 different fillers were used. The effect of Polymer concentration, combination and fillers on drug release rate was analyzed for the formulations F-1 to F-17. The tablets were subjected to physicochemical studies,...

  12. Survival of Poliovirus in Flowing Turbid Seawater Treated with Ultraviolet Light

    Science.gov (United States)

    Hill, W. F.; Hamblet, F. E.; Akin, E. W.

    1967-01-01

    The effectiveness of a model ultraviolet (UV) radiation unit for treating flowing turbid seawater contaminated with poliovirus was determined. At a turbidity of 70 ppm, the observed survival ratios ranged from 1.9 × 10-3 (99.81% reduction) to 1.5 × 10-4 (99.98% reduction) at flow rates ranging from 25 to 15 liters/min; no virus was recovered at flow rates of 10 and 5 liters/min. At a turbidity of 240 ppm, the observed survival ratios ranged from 3.2 × 10-2 (96.80% reduction) to 2.1 × 10-4 (99.98% reduction) at flow rates ranging from 25 to 5 liters/min. As expected, turbidity had an adverse influence on the effectiveness of UV radiation; however, by adjusting the flow rate of the seawater through the treatment unit, adequate disinfection was shown to be predictable. Images Fig. 1 PMID:4291955

  13. Peer Influence, Genetic Propensity, and Binge Drinking: A Natural Experiment and a Replication.

    Science.gov (United States)

    Guo, Guang; Li, Yi; Wang, Hongyu; Cai, Tianji; Duncan, Greg J

    2015-11-01

    The authors draw data from the College Roommate Study (ROOM) and the National Longitudinal Study of Adolescent Health to investigate gene-environment interaction effects on youth binge drinking. In ROOM, the environmental influence was measured by the precollege drinking behavior of randomly assigned roommates. Random assignment safeguards against friend selection and removes the threat of gene-environment correlation that makes gene-environment interaction effects difficult to interpret. On average, being randomly assigned a drinking peer as opposed to a nondrinking peer increased college binge drinking by 0.5-1.0 episodes per month, or 20%-40% the average amount of binge drinking. However, this peer influence was found only among youths with a medium level of genetic propensity for alcohol use; those with either a low or high genetic propensity were not influenced by peer drinking. A replication of the findings is provided in data drawn from Add Health. The study shows that gene-environment interaction analysis can uncover social-contextual effects likely to be missed by traditional sociological approaches.

  14. Electrochemical formation of green rusts in deaerated seawater-like solutions

    Energy Technology Data Exchange (ETDEWEB)

    Refait, Ph., E-mail: prefait@univ-lr.fr [Laboratoire d' etude des materiaux en milieux agressifs (LEMMA), EA 3167, Universite de La Rochelle, Bat. Marie Curie, Av. Michel Crepeau, F-17 042 La Rochelle Cedex 01 (France); Fed. de Recherche en Environnement et Developpement Durable, FR CNRS 3097 (France); Nguyen, D.D. [Laboratoire d' etude des materiaux en milieux agressifs (LEMMA), EA 3167, Universite de La Rochelle, Bat. Marie Curie, Av. Michel Crepeau, F-17 042 La Rochelle Cedex 01 (France); Hue University' s College of Education, Hue (Viet Nam); Jeannin, M. [Laboratoire d' etude des materiaux en milieux agressifs (LEMMA), EA 3167, Universite de La Rochelle, Bat. Marie Curie, Av. Michel Crepeau, F-17 042 La Rochelle Cedex 01 (France); Fed. de Recherche en Environnement et Developpement Durable, FR CNRS 3097 (France); Sable, S. [Littoral, Environnement et Societe (LiENSs), UMR 6250, CNRS-Univ. La Rochelle, Bat. Marie Curie, Av. Michel Crepeau, F-17 042 La Rochelle Cedex 01 (France); Fed. de Recherche en Environnement et Developpement Durable, FR CNRS 3097 (France); Langumier, M. [Laboratoire d' etude des materiaux en milieux agressifs (LEMMA), EA 3167, Universite de La Rochelle, Bat. Marie Curie, Av. Michel Crepeau, F-17 042 La Rochelle Cedex 01 (France); Littoral, Environnement et Societe (LiENSs), UMR 6250, CNRS-Univ. La Rochelle, Bat. Marie Curie, Av. Michel Crepeau, F-17 042 La Rochelle Cedex 01 (France); Fed. de Recherche en Environnement et Developpement Durable, FR CNRS 3097 (France); Sabot, R. [Laboratoire d' etude des materiaux en milieux agressifs (LEMMA), EA 3167, Universite de La Rochelle, Bat. Marie Curie, Av. Michel Crepeau, F-17 042 La Rochelle Cedex 01 (France); Fed. de Recherche en Environnement et Developpement Durable, FR CNRS 3097 (France)

    2011-07-15

    Highlights: > Sulphated green rust could be electro-generated on carbon steel in anoxic seawater-like electrolytes. > Rust layers grown during 11 years on carbon steel in natural seawater were thoroughly characterised by {mu}-Raman spectroscopy. > The mechanism of marine corrosion of carbon steel in anoxic conditions could be specified. - Abstract: Carbon steel electrodes were polarised at a potential {approx}150 mV higher than the open circuit potential, in a deaerated seawater-like electrolyte (0.5 mol dm{sup -3} NaCl, 0.03 mol dm{sup -3} Na{sub 2}SO{sub 4}, 0.003 mol dm{sup -3} NaHCO{sub 3}). X-ray diffraction and {mu}-Raman analysis demonstrated that a layer mainly composed of GR(SO{sub 4}{sup 2-}) had grown on the steel surface. GR(SO{sub 4}{sup 2-}) was accompanied by traces of GR(CO{sub 3}{sup 2-}). Similar experiments performed in a solution composed of 0.3 mol dm{sup -3} of Na{sub 2}SO{sub 4} and 0.03 mol dm{sup -3} of NaHCO{sub 3} led to the same result. The nature of the GR forming on steel is thus mainly linked to the sulphate to carbonate concentration ratio. Finally, carbon steel coupons immersed for 11 years in the harbour of La Rochelle (Atlantic coast) were removed from seawater for analysis. The inner part of the rust layer proved to be mainly composed of magnetite, GR(SO{sub 4}{sup 2-}) and iron sulphide FeS. This definitively confirms that GR(SO{sub 4}{sup 2-}), as Fe{sub 3}O{sub 4} and FeS, can form from steel in O{sub 2}-depleted environments.

  15. Analysis of Influence of Heat Insulation on the Thermal Regime of Storage Tanks with Liquefied Natural Gas

    Science.gov (United States)

    Maksimov, Vyacheslav I.; Nagornova, Tatiana A.; Glazyrin, Viktor P.; Shestakov, Igor A.

    2016-02-01

    Is numerically investigated the process of convective heat transfer in the reservoirs of liquefied natural gas (LNG). The regimes of natural convection in a closed rectangular region with different intensity of heat exchange at the external borders are investigated. Is solved the time-dependent system of energy and Navier-Stokes equations in the dimensionless variables "vorticity - the stream function". Are obtained distributions of the hydrodynamic parameters and temperatures, that characterize basic regularities of the processes. The special features of the formation of circulation flows are isolated and the analysis of the temperature distribution in the solution region is carried out. Is shown the influence of geometric characteristics and intensity of heat exchange on the outer boundaries of reservoir on the temperature field in the LNG storage.

  16. Analysis of Influence of Heat Insulation on the Thermal Regime of Storage Tanks with Liquefied Natural Gas

    Directory of Open Access Journals (Sweden)

    Maksimov Vyacheslav I.

    2016-01-01

    Full Text Available Is numerically investigated the process of convective heat transfer in the reservoirs of liquefied natural gas (LNG. The regimes of natural convection in a closed rectangular region with different intensity of heat exchange at the external borders are investigated. Is solved the time-dependent system of energy and Navier-Stokes equations in the dimensionless variables “vorticity – the stream function”. Are obtained distributions of the hydrodynamic parameters and temperatures, that characterize basic regularities of the processes. The special features of the formation of circulation flows are isolated and the analysis of the temperature distribution in the solution region is carried out. Is shown the influence of geometric characteristics and intensity of heat exchange on the outer boundaries of reservoir on the temperature field in the LNG storage.

  17. The Influence of Repeated Teaching and Reflection on Preservice Teachers' Views of Inquiry and Nature of Science

    Science.gov (United States)

    Lotter, Christine; Singer, Jonathan; Godley, Jenice

    2009-12-01

    This study describes the influence of a secondary science methods program on secondary science preservice teachers’ views and enactment of nature of science and inquiry-based instructional practices. Built into the structure of this program were three cycles of practice teaching and reflection in which the preservice teachers focused on key pedagogical ideas in classroom settings with middle and high school students. The nine secondary preservice teachers improved both their understanding and enactment of inquiry and nature of science throughout the program period. This study provides evidence of the importance of incorporating multiple low-stakes practicum experiences that are closely tied to methods course goals that are highly scaffolded through both methods instructor and cooperating teacher support and tied to analytic self-reflection.

  18. Influence of environmental variables on the structure and composition of soil bacterial communities in natural and constructed wetlands.

    Science.gov (United States)

    Arroyo, Paula; Sáenz de Miera, Luis E; Ansola, Gemma

    2015-02-15

    Bacteria are key players in wetland ecosystems, however many essential aspects regarding the ecology of wetland bacterial communities remain unknown. The present study characterizes soil bacterial communities from natural and constructed wetlands through the pyrosequencing of 16S rDNA genes in order to evaluate the influence of wetland variables on bacterial community composition and structure. The results show that the composition of soil bacterial communities was significantly associated with the wetland type (natural or constructed wetland), the type of environment (lagoon, Typha or Salix) and three continuous parameters (SOM, COD and TKN). However, no clear associations were observed with soil pH. Bacterial diversity values were significantly lower in the constructed wetland with the highest inlet nutrient concentrations. The abundances of particular metabolic groups were also related to wetland characteristics. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. The Influence of Urban Natural and Built Environments on Physiological and Psychological Measures of Stress— A Pilot Study

    Directory of Open Access Journals (Sweden)

    Kurt Beil

    2013-03-01

    Full Text Available Environments shape health and well-being, yet little research has investigated how different real-world environmental settings influence the well-known determinant of health known as stress. Using a cross-over experimental design; this pilot study investigated the effect of four urban environments on physiological and psychological stress measures. Participants (N = 15 were exposed on separate days to one of the four settings for 20 min. These settings were designated as Very Natural; Mostly Natural; Mostly Built and Very Built. Visitation order to the four settings was individually randomized. Salivary cortisol and alpha-amylase; as well as self-report measures of stress; were collected before and after exposure to each setting. Gender was included as a variable in analysis; and additional data about environmental self-identity, pre-existing stress, and perceived restorativeness of settings were collected as measures of covariance. Differences between environmental settings showed greater benefit from exposure to natural settings relative to built settings; as measured by pre-to-post changes in salivary amylase and self-reported stress; differences were more significant for females than for males. Inclusion of covariates in a regression analysis demonstrated significant predictive value of perceived restorativeness on these stress measures, suggesting some potential level of mediation. These data suggest that exposure to natural environments may warrant further investigation as a health promotion method for reducing stress.

  20. Influences of High-Level Features, Gaze, and Scene Transitions on the Reliability of BOLD Responses to Natural Movie Stimuli

    Science.gov (United States)

    Lu, Kun-Han; Hung, Shao-Chin; Wen, Haiguang; Marussich, Lauren; Liu, Zhongming

    2016-01-01

    Complex, sustained, dynamic, and naturalistic visual stimulation can evoke distributed brain activities that are highly reproducible within and across individuals. However, the precise origins of such reproducible responses remain incompletely understood. Here, we employed concurrent functional magnetic resonance imaging (fMRI) and eye tracking to investigate the experimental and behavioral factors that influence fMRI activity and its intra- and inter-subject reproducibility during repeated movie stimuli. We found that widely distributed and highly reproducible fMRI responses were attributed primarily to the high-level natural content in the movie. In the absence of such natural content, low-level visual features alone in a spatiotemporally scrambled control stimulus evoked significantly reduced degree and extent of reproducible responses, which were mostly confined to the primary visual cortex (V1). We also found that the varying gaze behavior affected the cortical response at the peripheral part of V1 and in the oculomotor network, with minor effects on the response reproducibility over the extrastriate visual areas. Lastly, scene transitions in the movie stimulus due to film editing partly caused the reproducible fMRI responses at widespread cortical areas, especially along the ventral visual pathway. Therefore, the naturalistic nature of a movie stimulus is necessary for driving highly reliable visual activations. In a movie-stimulation paradigm, scene transitions and individuals’ gaze behavior should be taken as potential confounding factors in order to properly interpret cortical activity that supports natural vision. PMID:27564573

  1. Experimental investigation of the influence of natural convection and end-effects on Rayleigh streaming in a thermoacoustic engine.

    Science.gov (United States)

    Ramadan, Islam A; Bailliet, Hélène; Valière, Jean-Christophe

    2018-01-01

    The influence of both the natural convection and end-effects on Rayleigh streaming pattern in a simple standing-wave thermoacoustic engine is investigated experimentally at different acoustic levels. The axial mean velocity inside the engine is measured using both Laser Doppler Velocimetry and Particle Image Velocimetry. The mean flow patterns are categorized in three different regions referred to as "cold streaming" region, "hot streaming" region, and "end-effects" region. In the cold streaming region, the dominant phenomenon is Rayleigh streaming and the mean velocity measurements correspond well with the theoretical expectations of Rayleigh streaming at low acoustic levels. At higher acoustic levels, the measurements deviate from the theoretical expectations which complies with the literature. In the hot streaming region, temperature measurements reveal that the non-uniformity of the resonator wall temperature is the origin of natural convection flow. Velocity measurements show that natural convection flow superimposes on the Rayleigh streaming flow so that the measured mean velocity deviates from the theoretical expectations of Rayleigh streaming. In the last region, the measured mean velocity is very different from Rayleigh streaming due to the combined effects of both the flow disturbances generated near the extremity of the stack and the natural convection flow.

  2. Influence of daylight on the fate of silver and zinc oxide nanoparticles in natural aquatic environments

    International Nuclear Information System (INIS)

    Odzak, Niksa; Kistler, David; Sigg, Laura

    2017-01-01

    Nanoparticles, such as silver (Ag-NP) and zinc oxide (ZnO-NP), are increasingly used in many consumer products. These nanoparticles (NPs) will likely be exposed to the aquatic environment (rain, river, lake water) and to light (visible and UV) in the products where they are applied, or after those products are discharged. Dissolution of Ag-NP and ZnO-NP is an important process because the dissolved Ag + and Zn 2+ are readily available and toxic for aquatic organisms. The objective of this study was to investigate the role of daylight (UV and visible) for the fate of engineered Ag-NP and ZnO-NPs in different types of natural waters. Ag-NP and ZnO-NP were exposed to rainwater, river Rhine, and lake waters (Greifen, Lucerne, Cristallina, Gruère) under different light conditions (no light, UV 300–400 nm and visible light 400–700 nm) for up to 8 days. Stronger agglomeration of Ag-NP was observed in the waters with higher ionic strength in comparison to those with lower ionic strength. Visible light tended to increase the dissolution of Ag-NP under most natural water conditions in comparison to dark conditions, whereas UV-light led to decreased dissolved Ag + after longer exposure time. These effects illustrate the dynamic interactions of Ag-NP with light, which may lead both to increased oxidation and to increased reduction of Ag + by organic compounds under UV-light. In the case of ZnO-NP, agglomeration occurred at higher ionic strength, but the effects of pH were predominant for dissolution, which occurred up to concentrations close to the solubility limit of ZnO(s) at pH around 8.2 and to nearly complete dissolution of ZnO-NP at lower pH (pH 4.8–6.5), with both visible and UV-light facilitating dissolution. This study thus shows that light conditions play an important role in the dissolution processes of nanoparticles. - Highlights: • Effects of visible and UV-light on dissolution of silver and zinc oxide nanoparticles were examined. • Natural waters

  3. Influence of Natural Zeolite on Performance of Laying Hens and Egg Quality

    OpenAIRE

    ÖZTÜRK, Ergin; ERENER, Güray; SARICA, Musa

    2014-01-01

    This experiment was conducted to study the effects of natural zeolite on the performance of laying hens. One hundred and eighty 37-week-old Babcock B-300 hens were fed with a diet containing 0, 20, 40, 60 and 80 g clinoptilolite/kg in an experiment consisting of 36 hens per treatment during a 4x28 days experimental period. All feeding programs were isocaloric and isonitrogenous. Hens were put at random into 5 treatment groups (12 replicates and 36 hens per treatment). No significant dietar...

  4. INFLUENCE OF NATURAL IMMUNOMODULATORS ON PROTEIN FRACTIONS AND CORTISOL CONTENT IN RABBIT BLOOD UNDER STRESS

    Directory of Open Access Journals (Sweden)

    Grabovskyi S.

    2015-08-01

    Full Text Available The results of determination of protein fractions, cortisol content in blood of rabbits, which further added to the feed of natural origin biologically active substances are presented in the article. As an antistressors and immunomodulators in pre-slaughter period are using of spleen extract biologically active substances were obtained with ultrasound application. The purpose of research — determination of changes of protein fractions, cortisol content in rabbits blood before slaughter and their correction of natural origin biologically active substances (spleen extract. Object and research methods. The experiment was conducted on 15 rabbits with standard diet. Three groups of rabbits five month of age (5 rabbits each was formed for research. The spleen extract were using as an biologically active substances to the feed rabbits in pre-slaughter period (five days before slaughter. The extracts were applied to feed by aerosol method (70 °alcohol solution of spleen extract volume of 1.4 ml per rabbit (group I. The rabbits (group II received to the feed in the same way of 70 °alcohol solution in the same volume. The control group rabbits received the standard feed in the same volume. The feed eating by rabbits was exercised daily. The rabbits ate food completely. The rabbits slaughter was carried out in the morning. The blood plasma protein fractions separation was carried out by horizontal electrophoresis in polyacrylamide gel (PAAG. Mathematical treatment of the research results worked statistically using the software package Statistica 6.0 and Microsoft Excel for Windows XP. Probability differences was assessed by Student t-test and results considered likely at P ≤ 0.05. Results and discussion. We measured the ratio of blood plasma protein fractions of rabbits, which in addition to the feed fed of natural origin biologically active substances. As a result of research was found that aerosol introduction of the spleen extract to the rabbits

  5. Physico-chemical behavior of radionuclides in seawater

    International Nuclear Information System (INIS)

    Kimura, Yuichiro; Ogawa, Yoshihiro; Honda, Yoshihide; Katsurayama, Kosuke.

    1980-01-01

    To elucidate the physico-chemical states of radionuclides in seawater in relation to uptake by the marine biosphere, the physicochemical behavior of radiocobalt, radioruthenium and radiocerium in seawater was investigated by electrodialysis, high-voltage paper electrophoresis, and also by paper chromatography for nitrosylruthenium complexes. Most of the radiocobalt in seawater behaved as dialytic cations. However, these cationic species were not necessarily simple divalent, because their electrophoretic bands were rather diffuse and showed two peaks temporarily. The electroneutral form also increased with aging in seawater. The radioruthenium in seawater showed relatively a number of well-defined species which could be readily classified into anionic, cationic, electroneutral, colloidal or particulate, non-dialytic and more or less adsorbable species. The radioruthenium in the chloro and nitratonitrosylruthenium complexes occurred mainly electroneutral and anionic species, while nitro and binuclear oxygen-bridged nitratonitrosylruthenium complexes showed dominant anionic species. The hydrolysis of higher nitro and nitratonitrosylruthenium complexes to lower ones was demonstrated with aging in seawater by paper chromatography. The radiocerium in seawater showed initially cationic species. However, the electroneutral and anionic species were revealed with aging by electrodialysis. The radiocerium were strongly adsorbed on filter paper at the starting band in paper electrophoresis, presumably because of the formation of strongly adsorbable or insoluble hydrolytic species or particle formation. (author)

  6. Influence of dilution and nature of the interaction on surface and interface magnetism

    International Nuclear Information System (INIS)

    Tsallis, C.

    1986-01-01

    The recent theoretical effort of the Rio de Janeiro/CBPF group on surface magnetism is tutorially reviewed. Within a real space renormalization group framework, we analyse the influence of factors such as the number of states per spin (q-state Potts m