WorldWideScience

Sample records for salt structures migrating

  1. Reverse time migration of prism waves for salt flank delineation

    KAUST Repository

    Dai, Wei; Schuster, Gerard T.

    2013-01-01

    In this paper, we present a new reverse time migration method for imaging salt flanks with prism wave reflections. It consists of four steps: (1) migrating the seismic data with conventional RTM to give the RTM image; (2) using the RTM image as a reflectivity model to simulate source-side reflections with the Born approximation; (3) zero-lag correlation of the source-side reflection wavefields and receiver-side wavefields to produce the prism wave migration image; and (4) repeating steps 2 and 3 for the receiver-side reflections. An advantage of this method is that there is no need to pick the horizontal reflectors prior to migration of the prism waves. It also separately images the vertical structures at a different step to reduce crosstalk interference. The disadvantage of prism wave migration algorithm is that its computational cost is twice that of conventional RTM. The empirical results with a salt model suggest that prism wave migration can be an effective method for salt flank delineation in the absence of diving waves.

  2. Reverse time migration of prism waves for salt flank delineation

    KAUST Repository

    Dai, Wei

    2013-09-22

    In this paper, we present a new reverse time migration method for imaging salt flanks with prism wave reflections. It consists of four steps: (1) migrating the seismic data with conventional RTM to give the RTM image; (2) using the RTM image as a reflectivity model to simulate source-side reflections with the Born approximation; (3) zero-lag correlation of the source-side reflection wavefields and receiver-side wavefields to produce the prism wave migration image; and (4) repeating steps 2 and 3 for the receiver-side reflections. An advantage of this method is that there is no need to pick the horizontal reflectors prior to migration of the prism waves. It also separately images the vertical structures at a different step to reduce crosstalk interference. The disadvantage of prism wave migration algorithm is that its computational cost is twice that of conventional RTM. The empirical results with a salt model suggest that prism wave migration can be an effective method for salt flank delineation in the absence of diving waves.

  3. Migration of brine inclusions in salt

    International Nuclear Information System (INIS)

    Pigford, T.H.

    1982-01-01

    Theories of the migration of brine inclusions in salt are interpreted as simple physical processes, and theories by Russian and U.S. workers are shown to yield the same results. The migration theory is used to predict threshold temperature gradients below which migration of brine inclusions should not occur. The predicted threshold gradients are compared with the temperature gradients expected at the Waste Isolation Pilot Plant in New Mexico. The theory of a threshold gradient helps explain the existence of brine inclusions in natural salt deposits

  4. Pressure-driven brine migration in a salt repository

    International Nuclear Information System (INIS)

    Hwang, Y.; Chambre, P.L.; Pigford, T.H.; Lee, W.W.L.

    1989-01-01

    The traditional view is that salt is the ideal rock for isolation of nuclear waste because it is ''dry'' and probably ''impermeable.'' The existence of salt through geologic time is prima facie evidence of such properties. Experiments and experience at potential salt sites for geologic repositories have indicated that while porosity and permeability of salt are low, the salt may be saturated with brine. If this hypothesis is correct, then it is possible to have brine flow due to pressure differences within the salt. If there is pressure-driven brine migration in salt repositories then it is paramount to know the magnitude of such flow because inward brine flow would affect the corrosion rate of nuclear waste containers and outward brine flow might affect radionuclide transport rates. Brine exists in natural salt as inclusions in salt crystals and in grain boundaries. Brine inclusions in crystals move to nearby grain boundaries when subjected to a temperature gradient, because of temperature-dependent solubility of salt. Brine in grain boundaries moves under the influence of a pressure gradient. When salt is mined to create a waste repository, brine from grain boundaries will migrate into the rooms, tunnels and boreholes because these cavities are at atmospheric pressure. After a heat-emitting waste package is emplaced and backfilled, the heat will impose a temperature gradient in the surrounding salt that will cause inclusions in the nearby salt to migrate to grain boundaries within a few years, adding to the brine that was already present in the grain boundaries. The formulation of brine movement with salt as a thermoelastic porous medium, in the context of the continuum theory of mixtures, has been described. In this report we show the mathematical details and discuss the results predicted by this analysis

  5. Fluid migration studies in salt

    International Nuclear Information System (INIS)

    Shefelbine, H.C.; Raines, G.E.

    1980-01-01

    This discussion will be limited to the migration of water trapped in the rock salt under the influence of the heat field produced by nuclear waste. This is of concern because hypotheticl scenarios have been advanced in which this fluid movement allows radionuclides to escape to the biosphere. While portions of these scenarios are supported by observation, none of the complete scenarios has been demonstrated. The objectives of the present fluid migration studies are two-fold: 1. determine the character of the trapped fluid in terms of quantity, habitat and chemical constituents; and 2. define the mechanisms that cause the fluid to migrate toward heat sources. Based on the observations to date, fluid migration will not have a major impact on repository integrity. However, the above objectives will be pursued until the impacts, if any, can be quantified

  6. Thermal-gradient migration of brine inclusions in salt crystals

    International Nuclear Information System (INIS)

    Yagnik, S.K.

    1982-09-01

    It has been proposed that high-level nuclear waste be disposed in a geologic repository. Natural-salt deposits, which are being considered for this purpose, contain a small volume fraction of water in the form of brine inclusions distributed throughout the salt. Radioactive-decay heating of the nuclear wastes will impose a temperature gradient on the surrounding salt which mobilizes the brine inclusions. Inclusions filled completely with brine migrate up the temperature gradient and eventually accumulate brine near the buried waste forms. The brine may slowly corrode or degrade the waste forms which is undesirable. In this work, thermal gradient migration of both all-liquid and gas-liquid inclusions was experimentally studied in synthetic single crystals of NaCl and KCl using a hot-stage attachment to an optical microscope which was capable of imposing temperature gradients and axial compressive loads on the crystals. The migration velocities of the inclusions were found to be dependent on temperature, temperature gradient, and inclusion shape and size. The velocities were also dictated by the interfacial mass transfer resistance at brine/solid interface. This interfacial resistance depends on the dislocation density in the crystal, which in turn, depends on the axial compressive loading of the crystal. At low axial loads, the dependence between the velocity and temperature gradient is non-linear.At high axial loads, however, the interfacial resistance is reduced and the migration velocity depends linearly on the temperature gradient. All-liquid inclusions filled with mixed brines were also studied. For gas-liquid inclusions, three different gas phases (helium, air and argon) were compared. Migration studies were also conducted on single crystallites of natural salt as well as in polycrystalline natural salt samples. The behavior of the inclusions at large angle grain boundaries was observed. 35 figures, 3 tables

  7. Thermal gradient migration of brine inclusions in salt crystals

    International Nuclear Information System (INIS)

    Yagnik, S.K.

    1982-01-01

    Natural salt deposits, which are being considered for high-level nuclear wastes repositories, contain a small volume fraction of water in the form of brine inclusions distributed throughout the salt. Radioactive decay heating of the nuclear wastes will impose a temperature gradient on the surrounding salt which mobilizes the brine inclusions. Inclusions filled completely with brine (the all-liquid inclusions) migrate up the temperature gradient and eventually accumulate brine near the buried waste forms. The brine may slowly corrode or degrade the waste forms which is undesirable. In the present work, thermal gradient migration of both all-liquid and gas-liquid inclusions was experimentally studied in synthetic single crystals of NaCl and KCl using a hot-stage attachment to an optical microscope which was capable of imposing temperature gradients and axial compressive loads on the crystals. The migration velocities of the inclusions were found to be dependent on temperature, temperature gradient, and inclusion shape and size. The velocities were also dictated by the interfacial mass transfer resistance at brine/solid interface. This interfacial resistance depends on the dislocation density in the crystal, which in turn, depends on the axial compressive loading of the crystal. At low axial loads, the dependence between the velocity and temperature gradient is nonlinear. At high axial loads, however, the interfacial resistance is reduced and the migration velocity depends linearly on the temperature gradient. All-liquid inclusions filled with mixed brines were also studied. For gas-liquid inclusions, three different gas phases (helium, air and argon) were compared. Migration studies were also conducted on single crystallites of natural salt as well as in polycrystalline natural salt samples. The behavior of the inclusions at large angle grain boudaries was observed

  8. Modeling Coupled THM Processes and Brine Migration in Salt at High Temperatures

    International Nuclear Information System (INIS)

    Rutqvist, Jonny; Blanco-Martin, Laura; Molins, Sergi; Trebotich, David; Birkholzer, Jens

    2015-01-01

    In this report, we present FY2015 progress by Lawrence Berkeley National Laboratory (LBNL) related to modeling of coupled thermal-hydrological-mechanical-chemical (THMC) processes in salt and their effect on brine migration at high temperatures. This is a combined milestone report related to milestone Salt R&D Milestone ''Modeling Coupled THM Processes and Brine Migration in Salt at High Temperatures'' (M3FT-15LB0818012) and the Salt Field Testing Milestone (M3FT-15LB0819022) to support the overall objectives of the salt field test planning.

  9. Modeling Coupled THM Processes and Brine Migration in Salt at High Temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Rutqvist, Jonny [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Blanco-Martin, Laura [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Molins, Sergi [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Trebotich, David [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Birkholzer, Jens [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2015-09-01

    In this report, we present FY2015 progress by Lawrence Berkeley National Laboratory (LBNL) related to modeling of coupled thermal-hydrological-mechanical-chemical (THMC) processes in salt and their effect on brine migration at high temperatures. This is a combined milestone report related to milestone Salt R&D Milestone “Modeling Coupled THM Processes and Brine Migration in Salt at High Temperatures” (M3FT-15LB0818012) and the Salt Field Testing Milestone (M3FT-15LB0819022) to support the overall objectives of the salt field test planning.

  10. Pressure-induced brine migration in consolidated salt in a repository

    International Nuclear Information System (INIS)

    Hwang, Y.; Chambre, P.L.; Lee, W.W.L.; Pigford, T.H.

    1987-06-01

    This report describes a mathematical model for brine migration through intact salt near a radioactive waste package emplaced in salt. Solutions indicate limited movement following ten years emplacement

  11. Threshold temperature gradient effect on migration of brine inclusions in salt

    International Nuclear Information System (INIS)

    Pigford, T.H.

    1987-01-01

    Theories of the migration of brine inclusions in salt were interpreted as simple physical processes, and theories by Russian and US workers were shown to yield the same results. The migration theory was used to predict threshold temperature gradients below which migration of brine inclusions should not occur. The predicted threshold gradients were compared with the temperature gradients expected at the Waste Isolation Pilot Plant in New Mexico. The theory of threshold gradients helps explain the existence of brine inclusions in natural salt deposits

  12. Brine migration in salt and its implications in the geologic disposal of nuclear waste

    International Nuclear Information System (INIS)

    Jenks, G.H.; Claiborne, H.C.

    1981-12-01

    This report respresents a comprehensive review and analysis of available information relating to brine migration in salt surrounding radioactive waste in a salt repository. The topics covered relate to (1) the characteristics of salt formations and waste packages pertinent to considerations of rates, amounts, and effects of brine migration, (2) experimental and theoretical information on brine migration, and (3) means of designing to minimize any adverse effects of brine migration. Flooding, brine pockets, and other topics were not considered, since these features will presumably be eliminated by appropriate site selection and repository design. 115 references

  13. Study of thermal-gradient-induced migration of brine inclusions in salt. Final report

    International Nuclear Information System (INIS)

    Olander, D.R.

    1984-08-01

    Natural salt deposits, which are being considered for high-level waste disposal, contain a small volume fraction of water in the form of brine inclusions distributed throughout the salt. Radioactive decay heating of the nuclear wastes will impose a temperature gradient on the surrounding salt which mobilizes the brine inclusions. Inclusions filled completely with brine (the all-liquid inclusions) migrate up the temperature gradient and eventually accumulate brine near the buried waste forms. The brine may slowly corrode or degrade the waste forms, which is undesirable. Therefore it is important to consider the migration of brine inclusions in salt under imposed temperature gradients to properly evaluate the performance of a future salt repository for nuclear wastes. The migration velocities of the inclusions were found to be dependent on temperature, temperature gradient, and inclusion shape and size. The velocities were also dictated by the interfacial mass transfer resistance at brine/solid interface. This interfacial resistance depends on the dislocation density in the crystal, which in turn, depends on the axial compressive loading of the crystal. At low axial loads, the dependence between the velocity and temperature gradient is nonlinear. At high axial loads, the interfacial resistance is reduced and the migration velocity depends linearly on the temperature gradient. All-liquid inclusions filled with mixed brines were also studied. For gas-liquid inclusions, helium, air and argon were compared. Migration studies were also conducted on single crystallites of natural salt as well as in polycrystalline natural salt samples. The behavior of the inclusions at large-ange grain boundaries was observed

  14. Study of thermal-gradient-induced migration of brine inclusions in salt. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Olander, D.R.

    1984-08-01

    Natural salt deposits, which are being considered for high-level waste disposal, contain a small volume fraction of water in the form of brine inclusions distributed throughout the salt. Radioactive decay heating of the nuclear wastes will impose a temperature gradient on the surrounding salt which mobilizes the brine inclusions. Inclusions filled completely with brine (the all-liquid inclusions) migrate up the temperature gradient and eventually accumulate brine near the buried waste forms. The brine may slowly corrode or degrade the waste forms, which is undesirable. Therefore it is important to consider the migration of brine inclusions in salt under imposed temperature gradients to properly evaluate the performance of a future salt repository for nuclear wastes. The migration velocities of the inclusions were found to be dependent on temperature, temperature gradient, and inclusion shape and size. The velocities were also dictated by the interfacial mass transfer resistance at brine/solid interface. This interfacial resistance depends on the dislocation density in the crystal, which in turn, depends on the axial compressive loading of the crystal. At low axial loads, the dependence between the velocity and temperature gradient is nonlinear. At high axial loads, the interfacial resistance is reduced and the migration velocity depends linearly on the temperature gradient. All-liquid inclusions filled with mixed brines were also studied. For gas-liquid inclusions, helium, air and argon were compared. Migration studies were also conducted on single crystallites of natural salt as well as in polycrystalline natural salt samples. The behavior of the inclusions at large-ange grain boundaries was observed.

  15. Brine migration test - Asse salt mine, Federal Republic of Germany

    International Nuclear Information System (INIS)

    Rothfuchs, T.; Wieczorek, K.; Feddersen, H.K.; Staupendahl, G.; Coyle, A.J.; Kalia, H.; Eckert, J.

    1988-03-01

    This document is the final report on the Cooperative German-American 'Brine Migration Tests' that were performed at the Asse Salt Mine in the Federal Republic of Germany (FRG), the Office of Nuclear Waste Isolation (ONWI), Columbus, Ohio, and the Institut fuer Tieflagerung (IfT), Braunschweig, of the Gesellschaft fuer Strahlen- und Umweltforschung mbH Muenchen (GSF). Final test and equipment design as well as manufacturing and installation was carried out by Westinghouse Electric Corporation. The tests were designed to simulate a nuclear waste repository to measure the effects of heat and gamma radiation on brine migration, salt decrepitation, disassociation of brine, and gases collected. The thermal mechanical behavior of salt, such as room closure, stresses and changes of the properties of salt are measured and compared with predicted behavior. The performance of an array of candidate waste package materials, test equipment and procedures under repository conditions will be evaluated with a view towards future in-depth testing of potential repository sites. (orig./RB)

  16. Domal salt brine migration experiments at Avery Island, Louisiana

    International Nuclear Information System (INIS)

    Krause, W.B.; Gnirk, P.F.

    1981-01-01

    Three in-situ brine migration experiments were performed in domal salt in the Avery Island mine located in southwestern Louisiana. The primary measurements included temperature, moisture collection, and pre- and post-test permeability at the experimental sites. Experimental data are discussed and compared with calculations based on the single-crystal brine migration theory. Comparisons indicate reasonable agreement between experiment and theory

  17. Thermal gradient brine inclusion migration in salt study: gas-liquid inclusions, preliminary model

    International Nuclear Information System (INIS)

    Olander, D.R.; Machiels, A.J.

    1979-10-01

    Natural salt deposits contain small cubical inclusions of brine distributed through the salt. Temperature gradients, resulting from storing heat-generating wastes in the salt, can cause the inclusions to move through the salt. Prediction of the rate and amount of brine-inclusion migration is necessary for the evaluation of bedded or domed salts as possible media for waste repositories. Inclusions filled exclusively with liquid migrate up the temperature gradient towards the heat source. The solubility of salt in the brine inclusion increases with temperature. Consequently, salt dissolves into the inclusion across the hot surface and crystallizes out at the cold surface. Diffusion of salt within the liquid phase from the hot to the cold faces causes the inclusions to move in the opposite direction. In so doing, they change shape and eventually become rectangular parallelipipeds with a width (dimension perpendicular to the thermal gradient) much larger than the thickness (dimension in the direction of the thermal gradient). The inclusions may also contain a gas phase predominantly consisting of water vapor. These entities are termed two-phase or gas-liquid inclusions. The two-phase inclusions usually migrate down the temperature gradient away from the heat source remaining more-or-less cubical. A two-phase inclusion also forms when an all-liquid inclusion reaches the waste package; upon opening up at the salt-package interface, the brine partially evaporates and the inclusion reseals with some insoluble gas trapped inside. These gas-liquid inclusions proceed to move down the temperature gradient, in the opposite sense of the all-liquid inclusions. The gas-liquid inclusions phenomenon provides a pathway by which radionuclides leached from the wasteform by the brine can be transported away from the waste package and thus might have greater access to the biosphere

  18. Brine migration test report: Asse Salt Mine, Federal Republic of Germany: Technical report

    International Nuclear Information System (INIS)

    Coyle, A.J.; Eckert, J.; Kalia, H.

    1987-01-01

    This report presents a summary of Brine Migration Tests which were undertaken at the Asse mine of the Federal Republic of Germany (FRG) under a bilateral US/FRG agreement. This experiment simulates a nuclear waste repository at the 800-m (2624-ft) level of the Asse salt mine in the Federal Republic of Germany. This report describes the Asse salt mine, the test equipment, and the pretest properties of the salt in the mine and in the vicinity of the test area. Also included are selected test data (for the first 28 months of operation) on the following: brine migration rates, thermomechaical behavior of the salt (including room closure, stress reading, and thermal profiles), borehole gas pressures, and borehole gas analyses. In addition to field data, laboratory analyses of pretest salt properties are included in this report. The operational phase of these experiments was completed on October 4, 1985, with the commencement of cooldown and the start of posttest activities. 7 refs., 68 figs., 48 tabs

  19. Solubility and speciation of actinides in salt solutions and migration experiments of intermediate level waste in salt formations

    International Nuclear Information System (INIS)

    1986-01-01

    A comprehensive study into the solubility of the actinides americium and plutonium in concentrated salt solutions, the release of radionuclides from various forms of conditioned ILW and the migration behaviour of these nuclides through geological material specific to the Gorleben site in Lower Saxony is described. A detailed investigation into the characterization of four highly concentrated salt solutions in terms of their pH, Eh, inorganic carbon contents and their densities is given and a series of experiments investigating the solubility of standard americium(III) and plutonium(IV) hydroxides in these solutions is described. Transuranic mobility studies for solutions derived from the standard hydroxides through salt and sand have shown the presence of at least two types of species present of widely differing mobility; one migrating with approximately the same velocity as the solvent front and the other strongly retarded. Actinide mobility data are presented and discussed for leachates derived from the simulated ILW in cement and data are also presented for the migration of the fission products in leachates derived from real waste solidified in cement and bitumen. Relatively high plutonium mobilities were observed in the case of the former and in the case of the real waste leachates, cesium was found to be the least retarded. The sorption of ruthenium was found to be largely associated with the insoluble residues of the natural rock salt rather than the halite itself. (orig./RB)

  20. Brine Migration in Heated Salt: Lessons Learned from Field Experiments

    Science.gov (United States)

    Kuhlman, K. L.; Matteo, E. N.; Mills, M.

    2017-12-01

    We summarize several interesting brine migration related phenomena hinted at in field experiments from field testing related to salt radioactive waste repositories in Germany and the US. Past heater tests in salt have shown 1) thermal-hydrological-mechanical coupling is quite strong during both heating and cooling; 2) chemical composition of brine evolves during heating, and comprises a mix of several water sources; and 3) acid gas (HCl) generation has been observed during past heater tests and may have multiple mechanisms for formation. We present a heated brine migration test design, formulated with these complexities in mind. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia LLC, a wholly owned subsidiary of Honeywell International Inc. for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA0003525.

  1. State-of-the-art review of brine migration studies in salt. Technical memorandum report RSI-0075

    International Nuclear Information System (INIS)

    Gnirk, P.F.; Krause, W.B.; Fossum, A.F.

    1981-09-01

    This report provides a state-of-the-art review of brine migration studies in rock salt. Emphasis is placed on the review of literature relating to brine migration phenomena around nuclear waste canisters. This review includes experimental work which has been conducted in the laboratory and in the field. In addition to the literature review, some additional thoughts on brine migration are given and a series of laboratory experiments is proposed. The proposed laboratory experiments are designed to determine whether or not a relationship exists between brine migration and temperature, temperature gradient and stress in rock salt. 34 references, 9 figures, 3 tables

  2. Effects of temperature, temperature gradients, stress, and irradiation on migration of brine inclusions in a salt repository

    International Nuclear Information System (INIS)

    Jenks, G.H.

    1979-07-01

    Available experimental and theoretical information on brine migration in bedded salt are reviewed and analyzed. The effects of temperature, thermal gradients, stress, irradiation, and pressure in a salt repository are among the factors considered. The theoretical and experimental (with KCl) results of Anthony and Cline were used to correlate and explain the available data for rates of brine migration at temperatures up to 250 0 C in naturally occurring crystals of bedded salt from Lyons and Hutchinson, Kansas. Considerations of the effects of stressing crystals of bedded salt on the migratin properties of brine inclusions within the crystals led to the conclusion that the most probable effects are a small fractional increase in the solubility of the salt within the liquid and a concomitant and equal fractional increase in the rate of the thermal gradient-induced migration of the brine. The greatest uncertainty relative to the prediction of rates of migration of brine into a waste emplacement cavity in bedded salt is associated with questions concerning the effects of the grain boundaries (within the aggregates of single crystals which comprise a bedded salt deposit) on brine migration through the deposit. The results of some of the estimates of rates and total amounts of brine inflow to HLW and SURF waste packages emplaced in bedded salt were included to illustrate the inflow volumes which might occur in a repository. The results of the brine inflow estimates for 10-year-old HLW emplaced at 150 kW/acre indicated inflow rates starting at 0.7 liter/year and totaling 12 liters at 30 years after emplacement. The results of the estimates for 10-year-old PWR SURF emplaced at 60 kW/acre indicated a constant inflow of 0.035 liter/year for the first 35 years after emplacement

  3. Weather and eared grebe winter migration near the Great Salt Lake, Utah

    Science.gov (United States)

    Williams, Augusta A.; Laird, Neil F.

    2018-03-01

    This study provides insight from the use of weather radar observations to understand the characteristics of the eared grebe migration near the Great Salt Lake (GSL) and provides unique information on weather conditions connected to these migration events. Doppler weather radar measurements from the Salt Lake City, Utah WSR-88D radar site (KMTX), along with meteorological surface and rawinsonde data, were used to identify and examine 281 eared grebe migration events across 15 winters from 1997/1998 through 2011/2012. An average of about 19 migration events occurred each winter with considerable interannual variability, as well as large variance in the spatial area and number of birds departing the GSL during each event. The migration events typically occurred during clear sky conditions in the presence of surface high pressure and colder than average surface temperatures. Migration events began 55 min after sunset, on average across the winter seasons, and in one case we demonstrate that an extended, nonstop flight was initiated of the departing eared grebes to northern Mexico. Eared grebes leaving the GSL largely flew above the freezing level with a mean northerly tailwind at flight altitude of 3.1 m s-1 and a westerly, cross-flight wind of 5.0 m s-1 while having an average flight speed at cruising altitude of 16.9 m s-1, or 61 km h-1. In addition to determining the variability of meteorological conditions during migration events across the 15 winters, atmospheric conditions during the largest migration event observed are presented and discussed.

  4. Weather and eared grebe winter migration near the Great Salt Lake, Utah.

    Science.gov (United States)

    Williams, Augusta A; Laird, Neil F

    2018-03-01

    This study provides insight from the use of weather radar observations to understand the characteristics of the eared grebe migration near the Great Salt Lake (GSL) and provides unique information on weather conditions connected to these migration events. Doppler weather radar measurements from the Salt Lake City, Utah WSR-88D radar site (KMTX), along with meteorological surface and rawinsonde data, were used to identify and examine 281 eared grebe migration events across 15 winters from 1997/1998 through 2011/2012. An average of about 19 migration events occurred each winter with considerable interannual variability, as well as large variance in the spatial area and number of birds departing the GSL during each event. The migration events typically occurred during clear sky conditions in the presence of surface high pressure and colder than average surface temperatures. Migration events began 55 min after sunset, on average across the winter seasons, and in one case we demonstrate that an extended, nonstop flight was initiated of the departing eared grebes to northern Mexico. Eared grebes leaving the GSL largely flew above the freezing level with a mean northerly tailwind at flight altitude of 3.1 m s -1 and a westerly, cross-flight wind of 5.0 m s -1 while having an average flight speed at cruising altitude of 16.9 m s -1 , or 61 km h -1 . In addition to determining the variability of meteorological conditions during migration events across the 15 winters, atmospheric conditions during the largest migration event observed are presented and discussed.

  5. Thermal-gradient migration of brine inclusions in salt

    International Nuclear Information System (INIS)

    Yagnik, S.K.

    1982-02-01

    It has been proposed that the high level nuclear waste be buried deep underground in a suitable geologic formation. Natural salt deposits have been under active consideration as one of the geologic formations where a nuclear waste repository may be built in future. The salt deposits, however, are known to contain a small amount (about 0.5 vol.%) of water in the form of brine inclusions which are dispersed throughout the medium. The temperature gradients imposed by the heat generating nuclear waste will mobilize these brine inclusions. It is important to know the rate and the amount of brine accumulating at the waste packages to properly evaluate the performance of a nuclear waste repository. An extensive experimental investigation of the migration velocities of brine inclusions in synthetic single crystals of NaCl and in polycrystalline natural salt crystals has been conducted. The results show that in a salt repository the brine inclusions within a grain would move with the diffusion controlled velocities. The brine reaching a grain boundary may be swept across, if the thermal gradient is high enough. Grain boundaries in polycrystalline rock salt are apparently quite weak and open up due to drilling the hole for a waste canister and to the thermal stresses which accompany the thermal gradient produced by the heat generating waste. The enhanced porosity allows the water reaching the grain boundary to escape by a vapor transport process

  6. Modeling Coupled THMC Processes and Brine Migration in Salt at High Temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Rutqvist, Jonny; Blanco Martin, Laura; Mukhopadhyay, Sumit; Houseworth, Jim; Birkholzer, Jens

    2014-08-14

    In this report, we present FY2014 progress by Lawrence Berkeley National Laboratory (LBNL) related to modeling of coupled thermal-hydrological-mechanical-chemical (THMC) processes in salt and their effect on brine migration at high temperatures. LBNL’s work on the modeling of coupled THMC processes in salt was initiated in FY2012, focusing on exploring and demonstrating the capabilities of an existing LBNL modeling tool (TOUGH-FLAC) for simulating temperature-driven coupled flow and geomechanical processes in salt. This work includes development related to, and implementation of, essential capabilities, as well as testing the model against relevant information and published experimental data related to the fate and transport of water. we provide more details on the FY2014 work, first presenting updated tools and improvements made to the TOUGH-FLAC simulator, and the use of this updated tool in a new model simulation of long-term THM behavior within a generic repository in a salt formation. This is followed by the description of current benchmarking and validations efforts, including the TSDE experiment. We then present the current status in the development of constitutive relationships and the dual-continuum model for brine migration. We conclude with an outlook for FY2015, which will be much focused on model validation against field experiments and on the use of the model for the design studies related to a proposed heater experiment.

  7. Structure and thermodynamics of molten salts

    International Nuclear Information System (INIS)

    Papatheodorou, G.N.

    1983-01-01

    This chapter investigates single-component molten salts and multicomponent salt mixtures. Molten salts provide an important testing ground for theories of liquids, solutions, and plasmas. Topics considered include molten salts as liquids (the pair potential, the radial distribution function, methods of characterization), single salts (structure, thermodynamic correlations), and salt mixtures (the thermodynamics of mixing; spectroscopy and structure). Neutron and X-ray scattering techniques are used to determine the structure of molten metal halide salts. The corresponding-states theory is used to obtain thermodynamic correlations on single salts. Structural information on salt mixtures is obtained by using vibrational (Raman) and electronic absorption spectroscopy. Charge-symmetrical systems and charge-unsymmetrical systems are used to examine the thermodynamics of salt mixtures

  8. Mechanism of intragranular migration of brine inclusions in salt

    International Nuclear Information System (INIS)

    Machiels, A.J.; Yagnik, S.; Olander, D.R.; Kohli, R.

    1981-01-01

    The dislocation-controlled migration process is qualitatively consistent with all experiments designed to test the hypothesis. It also explains the very large scatter of the measured velocities of small inclusions in crystals of high perfection. Larger inclusions in natural salt crystals, on the other hand, are not limited by the number of dislocation intersections at the dissolving face and these inclusions appear to move at the rate predicted by liquid diffusion control

  9. Petrofabric changes in heated and irradiated salt from Project Salt Vault, Lyons, Kansas

    International Nuclear Information System (INIS)

    Holdoway, K.A.

    1972-01-01

    Rock salt was heated and irradiated in situ by implanted radioactive wastes during the Project Salt Vault experiment which was carried out at Lyons, Kansas, in the abandoned Carey Salt mine between 1965 and 1967. It was found that irradiation results in coloration of the salt, producing colors ranging from blue-black nearest the radiation source, to pale blue and purple farther from the source. Bleached areas are common in the radiation-colored salt, many representing trails produced by the migration of fluid inclusions towards the heat source. These visible trails are thought to have formed during the cooling down of the salt after the removal of the heaters and radiation sources. The distribution of primary structures in the salt suggests that little migration, if any, occurred during the course of the experiment. It is proposed that radiolysis of the brine within the inclusions may have led to the production of gases which impeded or prevented migration. Evidence of strain was observed in slip planes at 4 in. (10 cm) and between 5.5 and 10 in. (13.5 to 25.4 cm) from the array hole. Deformed bleached areas in the salt between the areas were slip planes are developed suggest that slight plastic deformation or flow may have occurred at 6 in. (15 cm) from the array hole. Differential thermal analysis shows that the maximum amount of stored energy also occurs at 6 in. (15 cm) from the array hole. This region may therefore represent the zone where the combined effect of stress and radiation was greatest

  10. Migrational polarization in high-current density molten salt electrochemical devices

    Energy Technology Data Exchange (ETDEWEB)

    Braunstein, J.; Vallet, C.E.

    1977-01-01

    Electrochemical flux equations based on the thermodynamics of irreversible processes have been derived in terms of experimental transport coefficients for binary molten salt mixtures analogous to those proposed for high temperature batteries and fuel cells. The equations and some numerical solutions indicate steady state composition gradients of significant magnitude. The effects of migrational separation must be considered along with other melt properties in the characterization of electrode behavior, melt composition, operating temperatures and differences of phase stability, wettability and other physicochemical properties at positive and negative electrodes of high current density devices with mixed electrolytes.

  11. Bile salts as semiochemicals in fish

    Science.gov (United States)

    Buchinger, Tyler J.; Li, Weiming; Johnson, Nicholas S.

    2014-01-01

    Bile salts are potent olfactory stimuli in fishes; however the biological functions driving such sensitivity remain poorly understood. We provide an integrative review of bile salts as semiochemicals in fish. First, we present characteristics of bile salt structure, metabolism, and function that are particularly relevant to chemical communication. Bile salts display a systematic pattern of structural variation across taxa, are efficiently synthesized, and are stable in the environment. Bile salts are released into the water via the intestine, urinary tract, or gills, and are highly water soluble. Second, we consider the potential role of bile salts as semiochemicals in the contexts of detecting nearby fish, foraging, assessing risk, migrating, and spawning. Lastly, we suggest future studies on bile salts as semiochemicals further characterize release into the environment, behavioral responses by receivers, and directly test the biological contexts underlying olfactory sensitivity.

  12. Geology of the north end of the Salt Valley Anticline, Grand County, Utah

    International Nuclear Information System (INIS)

    Gard, L.M. Jr.

    1976-01-01

    The geology and hydrology of a portion of the Salt Valley anticline lying north of Moab, Utah, that is being studied as a potential site for underground storage of nuclear waste in salt are discussed. Selection of this area was based on recommendations made in an earlier appraisal of the potential of Paradox basin salt deposits for such use. Salt Valley anticline, a northwest-trending diapiric structure, consists of Mesozoic sedimentary rocks arched over a thick core of salt of the Paradox Member of the Middle Pennsylvanian Hermosa Formation. Salt began to migrate to form and/or develop this structure shortly after it was deposited, probably in response to faulting. This migration caused upwelling of the salt creating a linear positive area. This positive area, in turn, caused increased deposition of sediments in adjacent areas which further enhanced salt migration. Not until late Jurassic time had flowage of the salt slowed sufficiently to allow sediments of the Morrison and younger formations to be deposited across the salt welt. A thick cap of insoluble residue was formed on top of the salt diapir as a result of salt dissolution through time. The crest of the anticline is breached; it collapsed in two stages during the Tertiary Period. The first stage was graben collapse during the early Tertiary; the second stage occurred after Miocene regional uplift had caused downcutting streams to breach the salt core resulting in further collapse. The axis of the anticline is a narrow generally flat-floored valley containing a few hills composed of downdropped Mesozoic rocks foundered in thecaprock. The caprock, which underlies thin alluvium in the valley, is composed of contorted gypsum, shale, sandstone, and limestone--the insoluble residue of the Paradox salt

  13. Mass transfer and transport in salt repositories

    International Nuclear Information System (INIS)

    Pigford, T.H.; Chambre, P.L.; Lee, W.W.L.

    1989-02-01

    Salt is a unique rock isolation of nuclear waste because it is ''dry'' and nearly impermeable. In this paper we summarize some mass-transfer and transport analyses of salt repositories. First we analyses brine migration. Heating by high-level waste can cause brine in grain boundaries to move due to pressure-gradients. We analyze brine migration treating salt as a thermoelastic solid and found that brine migration is transient and localized. We use previously developed techniques to estimate release rates from waste packages by diffusion. Interbeds exist in salt and may be conduits for radionuclide migration. We analyze steady-state migration due to brine flow in the interbed, as a function of the Peclet number. Then we analyze transient mass transfer, both into the interbed and directly to salt, due only to diffusion. Finally we compare mass transfer rates of a waste cylinder in granite facing a fracture and in salt facing an interbed. In all cases, numerical illustrations of the analytic solution are given. 10 refs., 4 figs., 3 tabs

  14. Mechanical modeling of the growth of salt structures

    Energy Technology Data Exchange (ETDEWEB)

    Alfaro, Ruben Alberto Mazariegos [Texas A & M Univ., College Station, TX (United States)

    1993-05-01

    A 2D numerical model for studying the morphology and history of salt structures by way of computer simulations is presented. The model is based on conservation laws for physical systems, a fluid marker equation to keep track of the salt/sediments interface, and two constitutive laws for rocksalt. When buoyancy alone is considered, the fluid-assisted diffusion model predicts evolution of salt structures 2.5 times faster than the power-law creep model. Both rheological laws predict strain rates of the order of 4.0 x 10-15 s-1 for similar structural maturity level of salt structures. Equivalent stresses and viscosities predicted by the fluid-assisted diffusion law are 102 times smaller than those predicted by the power-law creep rheology. Use of East Texas Basin sedimentation rates and power-law creep rheology indicate that differential loading is an effective mechanism to induce perturbations that amplify and evolve to mature salt structures, similar to those observed under natural geological conditions.

  15. Describing migration spatial structure

    NARCIS (Netherlands)

    Rogers, A; Willekens, F; Little, J; Raymer, J

    The age structure of a population is a fundamental concept in demography and is generally depicted in the form of an age pyramid. The spatial structure of an interregional system of origin-destination-specific migration streams is, however, a notion lacking a widely accepted definition. We offer a

  16. [The productive structure and migration].

    Science.gov (United States)

    Fernandez, M

    1980-01-01

    The author discusses the possibility of determining the proper approach to the study of migration, with a focus on the importance of global, structural, and historical analysis of the phenomenon. A general theoretical outline is presented that tends to show migration as an integral part of the process of social change. The sociological focus on modernization as a theoretical guide influencing the study of migration in Latin America is evaluated. The concept of overpopulation is explained in relation to the migratory process, with reference to capitalist and non-capitalist forms of production.

  17. How do salt withdrawal minibasins form? Insights from forward modelling, and implications for hydrocarbon migration

    Science.gov (United States)

    Peel, Frank J.

    2014-09-01

    Existing models for the initiation of salt withdrawal minibasins focus on the role of triggers that exist within the minibasin, either stratigraphic (e.g. differential deposition) or tectonic (extension, translation or contraction). Existing studies tend to focus on complex settings, such as continental margins, which contain many different potential triggering mechanisms. It can be difficult in these settings to identify which process is responsible for minibasin initiation, or the influence of individual factors on their subsequent development. Salt withdrawal minibasins also exist in simpler settings, without any obvious intrinsic trigger; the region of the North German Basin used by Trusheim (1960) in the classic definition of salt withdrawal geometries was of this nature. There is no overall basal or surface slope, no major lateral movement, and there is no depositional heterogeneity. Previously recognized trigger processes for minibasin initiation do not apply in this benign setting, suggesting that other, potentially more fundamental, influences may be at work. A simple forward-modelling approach shows how, in the absence of any other mechanism, a new minibasin can develop as the consequence of salt movement driven by its neighbour, and families of withdrawal minibasins can propagate across a region from a single seed point. This new mechanism may explain how some minibasins appear to initiate before the sediment density has exceeded that of the underlying salt. The forward modelling also indicates that some minibasins begin to invert to form turtle anticlines before the underlying salt has been evacuated, so that the timing of turtle formation may not be diagnostic of weld formation. This mechanism may also give rise to salt-cored turtles that have a lens of salt trapped beneath their cores. These new findings have implications for hydrocarbon migration and trapping.

  18. Ambazone-lipoic acid salt: Structural and thermal characterization

    Energy Technology Data Exchange (ETDEWEB)

    Kacso, Irina [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath street, 400293 Cluj-Napoca (Romania); Racz, Csaba-Pal; Santa, Szabolcs [Babes-Bolyai' University, Faculty of Chemistry, 11 Arany Janos street, Cluj-Napoca (Romania); Rus, Lucia [' Iuliu Hatieganu' University of Medicine and Pharmacy, Faculty of Pharmacy, 6 Louis Pasteur street, 400349 Cluj-Napoca (Romania); Dadarlat, Dorin; Borodi, Gheorghe [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath street, 400293 Cluj-Napoca (Romania); Bratu, Ioan, E-mail: ibratu@gmail.com [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath street, 400293 Cluj-Napoca (Romania)

    2012-12-20

    Highlights: Black-Right-Pointing-Pointer Salt of Ambazone with lipoic acid obtained by solvent-drop grinding. Black-Right-Pointing-Pointer Ambazone lipoate salt crystallizes in monoclinic system. Black-Right-Pointing-Pointer FTIR data suggest the deprotonation of the lipoic acid. Black-Right-Pointing-Pointer Thermal behaviour different of ambazone salt as compared to the starting compounds. - Abstract: A suitable method for increasing the solubility, dissolution rate and consequently the bioavailability of poor soluble acidic or basic drugs is their salt formation. The aim of this study is to investigate the structural and thermal properties of the compound obtained by solvent drop grinding (SDG) method at room temperature, starting from the 1:1 molar ratios of ambazone (AMB) and {alpha}-lipoic acid (LA). The structural characterization was performed with X-ray powder diffraction (XRPD) and infrared spectroscopy (FTIR). The thermal behaviour of the obtained compound (AMB{center_dot}LA) was investigated by differential scanning calorimetry (DSC) and thermogravimetry (TG). The photopyroelectric calorimetry, in front detection configuration (FPPE), was applied to measure and compare the room temperature values of one dynamic thermal parameter (thermal effusivity) for starting and resulting compounds. Both structural and supporting calorimetric techniques pointed out a salt structure for AMB{center_dot}LA compound as compared to those of the starting materials.

  19. Modification of doping front migration in electrochemical devices and application to organic electronics

    International Nuclear Information System (INIS)

    Nolte, Marius; Wan Xianglong; Kopp, Olga; Hermes, Ina; Panz, Jan; Rahmanian, Afsaneh; Knoll, Meinhard

    2011-01-01

    Research highlights: → In this paper we demonstrate several ways of tuning the doping front migration process in polymer electronic multilayer structures for the first time. By altering the migration layer thickness the migration velocity may be controlled and it is possible to switch between migration mechanisms. The mechanism of delamination produces rapid jumps in migration velocity, while the addition of 2-hydroxyethylcellulose (HEC) can inhibit this effect. In case of vapor activation the migration velocity may be influenced by the relative humidity or by varying the concentration of hygroscopic salts added to the migration layer. The migration mechanisms can be explained in terms of diffusion, capillary transport, and delamination. Tuning the migration process may be used to construct polymer electronic structures such as enhancement and depletion type pseudo transistors and electrical switches (ON-OFF and OFF-ON) with an improved switching time of several minutes. The doping front width is determined by microscopic optical absorption spectroscopy and can be controlled by the concentration of the doping solution. In case of low concentrations the electrochromic effect of the double front is observed. - Abstract: We demonstrate several methods of modifying the doping front migration process in multilayer structures, enabling control of migration velocity and switching between different migration mechanisms. Sharp jumps in migration velocity may be induced using a delamination effect. The influence of migration layer thickness and composition is examined. Migration velocity may also be influenced by exposing the system to a defined relative humidity or by varying the concentration of a hygroscopic salt in the migration layer. The migration mechanisms can be explained in terms of diffusion, capillary transport, and delamination. By tailoring the migration process a variety of polymer electronic structures such as pseudo transistors (enhancement and depletion

  20. Compatibility of molten salt and structural materials

    International Nuclear Information System (INIS)

    Kawakami, Masahiro

    1994-01-01

    As the important factors for considering the compatibility of fuel salt and coolant salt with structural materials in molten salt reactors, there are the moisture remaining in molten salt and the fluorine potential in molten salt. In this study, as for the metals which are the main components of corrosion resistant alloys, the corrosion by the moisture remaining in molten salt and the dependence of the corrosion on fluorine potential were examined. As the molten salts, an eutectic molten salt LiF-BeF 2 was mainly used, and LiF-KF was used in combination. As the metallic materials, Cr, Ni and Cu which are the main components of corrosion resistant and heat resistant alloys, Hastelloy and Monel, were used. In the experiment, the metal pieces were immersed in the molten salt, and by sampling the molten salt, the change with time lapse of the concentration of the dissolved metals was examined. Besides, the electrochemical measurement was carried out for Cr, of which the corrosion was remarkable, and the change with time lapse of the dissolved ions was examined. The experimental setup, the experimental method, and the results of the immersion test and the electrochemical test are reported. The experiment on the corrosion of metals depending on fluorine potential is also reported. (K.I.)

  1. A Dual-Continuum Model for Brine Migration in Salt Associated with Heat-Generating Nuclear Waste: Fully Coupled Thermal-Hydro-Mechanical Analysis

    Science.gov (United States)

    Hu, M.; Rutqvist, J.

    2017-12-01

    The disposal of heat-generating nuclear waste in salt host rock establishes a thermal gradient around the waste package that may cause brine inclusions in the salt grains to migrate toward the waste package. In this study, a dual-continuum model is developed to analyze such a phenomenon. This model is based on the Finite Volume Method (FVM), and it is fully thermal-hydro-mechanical (THM) coupled. For fluid flow, the dual-continuum model considers flow in the interconnected pore space and also in the salt grains. The mass balance of salt and water in these two continua is separately established, and their coupling is represented by flux associated with brine migration. Together with energy balance, such a system produces a coupled TH model with strongly nonlinear features. For mechanical analysis, a new formulation is developed based on the Voronoi tessellated mesh. By relating each cell to several connected triangles, first-order approximation is constructed. The coupling between thermal and mechanical fields is only considered in terms of thermal expansion. And the coupling between the hydraulic and mechanical fields in terms of pore-volume effects is consistent with Biot's theory. Therefore, a fully coupled THM model is developed. Several demonstration examples are provided to verify the model. Last the new model is applied to analyze coupled THM behavior and the results are compared with experimental data.

  2. Compatibility of molten salt and structural materials

    Energy Technology Data Exchange (ETDEWEB)

    Kawakami, Masahiro [Toyohashi Univ. of Technology, Aichi (Japan)

    1994-12-01

    As the important factors for considering the compatibility of fuel salt and coolant salt with structural materials in molten salt reactors, there are the moisture remaining in molten salt and the fluorine potential in molten salt. In this study, as for the metals which are the main components of corrosion resistant alloys, the corrosion by the moisture remaining in molten salt and the dependence of the corrosion on fluorine potential were examined. As the molten salts, an eutectic molten salt LiF-BeF{sub 2} was mainly used, and LiF-KF was used in combination. As the metallic materials, Cr, Ni and Cu which are the main components of corrosion resistant and heat resistant alloys, Hastelloy and Monel, were used. In the experiment, the metal pieces were immersed in the molten salt, and by sampling the molten salt, the change with time lapse of the concentration of the dissolved metals was examined. Besides, the electrochemical measurement was carried out for Cr, of which the corrosion was remarkable, and the change with time lapse of the dissolved ions was examined. The experimental setup, the experimental method, and the results of the immersion test and the electrochemical test are reported. The experiment on the corrosion of metals depending on fluorine potential is also reported. (K.I.).

  3. Migration rates of brine inclusions in single crystals of NaCl

    International Nuclear Information System (INIS)

    Chou, I.M.

    1982-01-01

    Rock-salt deposits have been considered as a possible medium for the permanent storage of high-level radioactive wastes and spent fuel. Brine inclusions present in natural salt can migrate toward the waste if the temperature and the temperature gradients in the vicinity of the radioactive waste are large enough. This migration is due to the dissolution of salt at the hot side of the salt-brine interface, ion diffusion through the brine droplet, and the precipitation of salt at the cold side of the salt brine interface. In order to quantify the problem, the migration rate of these brine inclusions must be estimated under various repository conditions. This paper estimates migration rates for all-liquid brine inclusions in single crystals of NaCl by utilizing recent data for brines and the model of Anthony and Cline [T.R. Anthony and H.E. Cline, J. Appl. Phys., 42, pp. 3380-387 (1971)]. The predictions are compared with experimentally measured migration rates. 4 figures, 6 tables

  4. Radioactive waste isolation in salt: geochemistry of brine in rock salt in temperature gradients and gamma-radiation fields - a selective annotated bibliography

    International Nuclear Information System (INIS)

    Hull, A.B.; Williams, L.B.

    1985-07-01

    Evaluation of the extensive research concerning brine geochemistry and transport is critically important to successful exploitation of a salt formation for isolating high-level radioactive waste. This annotated bibliography has been compiled from documents considered to provide classic background material on the interactions between brine and rock salt, as well as the most important results from more recent research. Each summary elucidates the information or data most pertinent to situations encountered in siting, constructing, and operating a mined repository in salt for high-level radioactive waste. The research topics covered include the basic geology, depositional environment, mineralogy, and structure of evaporite and domal salts, as well as fluid inclusions, brine chemistry, thermal and gamma-radiation effects, radionuclide migration, and thermodynamic properties of salts and brines. 4 figs., 6 tabs

  5. Radioactive waste isolation in salt: geochemistry of brine in rock salt in temperature gradients and gamma-radiation fields - a selective annotated bibliography

    Energy Technology Data Exchange (ETDEWEB)

    Hull, A.B.; Williams, L.B.

    1985-07-01

    Evaluation of the extensive research concerning brine geochemistry and transport is critically important to successful exploitation of a salt formation for isolating high-level radioactive waste. This annotated bibliography has been compiled from documents considered to provide classic background material on the interactions between brine and rock salt, as well as the most important results from more recent research. Each summary elucidates the information or data most pertinent to situations encountered in siting, constructing, and operating a mined repository in salt for high-level radioactive waste. The research topics covered include the basic geology, depositional environment, mineralogy, and structure of evaporite and domal salts, as well as fluid inclusions, brine chemistry, thermal and gamma-radiation effects, radionuclide migration, and thermodynamic properties of salts and brines. 4 figs., 6 tabs.

  6. Geology of the north end of the Salt Valley Anticline, Grand County, Utah

    Science.gov (United States)

    Gard, Leonard Meade

    1976-01-01

    This report describes the geology and hydrology of a portion of the Salt Valley anticline lying north of Moab, Utah, that is being studied as a potential site for underground storage of nuclear waste in salt. Selection of this area was based on recommendations made in an earlier appraisal of the potential of Paradox basin salt deposits for such use. Part of sec. 5, T. 23 S., R. 20 E. has been selected as a site for subsurface investigation as a potential repository for radioactive waste. This site has easy access to transportation, is on public land, is isolated from human habitation, is not visible from Arches National Park, and the salt body lies within about 800 feet (244 m) of the surface. Further exploration should include investigation of possible ground water in the caprock and physical exploration of the salt body to identify a thick bed of salt for use as a storage zone that can be isolated from the shaly interbeds that possibly contain quantities of hydrocarbons. Salt Valley anticline, a northwest-trending diapiric structure, consists of Mesozoic sedimentary rocks arched over a thick core of salt of the Paradox Member of the Middle Pennsylvanian Hermosa Formation. Salt began to migrate to form and/or develop this structure shortly after it was deposited, probably in response to faulting. This migration caused upwelling of the salt creating a linear positive area. This positive area, in turn, caused increased deposition of sediments in adjacent areas which further enhanced salt migration. Not until late Jurassic time had flowage of the salt slowed sufficiently to allow sediments of the Morrison and younger formations to be deposited across the salt welt. A thick cap of insoluble residue was formed on top of the salt diapir as a result of salt dissolution through time. The crest of the anticline is breached; it collapsed in two stages during the Tertiary Period. The first stage was graben collapse during the early Tertiary; the second stage occurred after

  7. Brine: a computer program to compute brine migration adjacent to a nuclear waste canister in a salt repository

    International Nuclear Information System (INIS)

    Duckworth, G.D.; Fuller, M.E.

    1980-01-01

    This report presents a mathematical model used to predict brine migration toward a nuclear waste canister in a bedded salt repository. The mathematical model is implemented in a computer program called BRINE. The program is written in FORTRAN and executes in the batch mode on a CDC 7600. A description of the program input requirements and output available is included. Samples of input and output are given

  8. High salt-induced excess reactive oxygen species production resulted in heart tube malformation during gastrulation.

    Science.gov (United States)

    Gao, Lin-Rui; Wang, Guang; Zhang, Jing; Li, Shuai; Chuai, Manli; Bao, Yongping; Hocher, Berthold; Yang, Xuesong

    2018-09-01

    An association has been proved between high salt consumption and cardiovascular mortality. In vertebrates, the heart is the first functional organ to be formed. However, it is not clear whether high-salt exposure has an adverse impact on cardiogenesis. Here we report high-salt exposure inhibited basement membrane breakdown by affecting RhoA, thus disturbing the expression of Slug/E-cadherin/N-cadherin/Laminin and interfering with mesoderm formation during the epithelial-mesenchymal transition(EMT). Furthermore, the DiI + cell migration trajectory in vivo and scratch wound assays in vitro indicated that high-salt exposure restricted cell migration of cardiac progenitors, which was caused by the weaker cytoskeleton structure and unaltered corresponding adhesion junctions at HH7. Besides, down-regulation of GATA4/5/6, Nkx2.5, TBX5, and Mef2c and up-regulation of Wnt3a/β-catenin caused aberrant cardiomyocyte differentiation at HH7 and HH10. High-salt exposure also inhibited cell proliferation and promoted apoptosis. Most importantly, our study revealed that excessive reactive oxygen species(ROS)generated by high salt disturbed the expression of cardiac-related genes, detrimentally affecting the above process including EMT, cell migration, differentiation, cell proliferation and apoptosis, which is the major cause of malformation of heart tubes. © 2018 Wiley Periodicals, Inc.

  9. Synthesis, structure, and properties of azatriangulenium salts

    DEFF Research Database (Denmark)

    Laursen, B.W.; Krebs, Frederik C

    2001-01-01

    amines and, by virtue of its stepwise and irreversible nature, provides a powerful tool for the preparation of a wide variety of new heterocyclic carbenium salts. Several derivatives of the three new oxygen- and/or nitrogen-bridged triangulenium salts, azadioxa- (6), diazaoxa- (7......), and triazatriangulenium (4), have been synthesized and their physicochemical properties have been investigated. Crystal structures for compounds 2 b-PF6: 2d-PF6, 4b-BF4, 4c-BF4, 6e-BF4, and 8 are reported. The different packing modes found for the triazatriagulenium salts are discussed in relation to the electrostatic...

  10. Corridors of crestal and radial faults linking salt diapirs in the Espírito Santo Basin, SE Brazil

    Science.gov (United States)

    Mattos, Nathalia H.; Alves, Tiago M.

    2018-03-01

    This work uses high-quality 3D seismic data to assess the geometry of fault families around salt diapirs in SE Brazil (Espírito Santo Basin). It aims at evaluating the timings of fault growth, and suggests the generation of corridors for fluid migration linking discrete salt diapirs. Three salt diapirs, one salt ridge, and five fault families were identified based on their geometry and relative locations. Displacement-length (D-x) plots, Throw-depth (T-z) data and structural maps indicate that faults consist of multiple segments that were reactivated by dip-linkage following a preferential NE-SW direction. This style of reactivation and linkage is distinct from other sectors of the Espírito Santo Basin where the preferential mode of reactivation is by upwards vertical propagation. Reactivation of faults above a Mid-Eocene unconformity is also scarce in the study area. Conversely, two halokinetic episodes dated as Cretaceous and Paleogene are interpreted below a Mid-Eocene unconformity. This work is important as it recognises the juxtaposition of permeable strata across faults as marking the generation of fault corridors linking adjacent salt structures. In such a setting, fault modelling shows that fluid will migrate towards the shallower salt structures along the fault corridors first identified in this work.

  11. Nuclear waste repository simulation experiments (brine migration), Asse Mine of the Federal Republic of Germany: Quarterly brine migration data report, October--December 1985

    International Nuclear Information System (INIS)

    Eckert, J.L.; Kalia, H.N.; Coyle, A.J.

    1988-03-01

    The tenth brine migration data report describes experiments simulating a nuclear waste repository at the 800-m (2624-ft) level of the Asse Salt Mine in the Federal Republic of Germany from May 1983 through December 1985. This report describes the test equipment, the Asse Salt Mine, and the pretest properties of the salt in the test gallery. This report includes test data for 31 months of operations on brine migration rates, borehole pressure, salt temperatures and thermomechanical behavior of the salt. 3 refs., 118 figs., 93 tabs

  12. Brine migration test for Asse Mine, Federal Republic of Germany: final test plan

    International Nuclear Information System (INIS)

    1983-07-01

    The United States and the Federal Republic of Germany (FRG) will conduct a brine migration test in the Asse Salt Mine in the FRG as part of the US/FRG Cooperative Radioactive Waste Management Agreement. Two sets of two tests each will be conducted to study both liquid inclusion migration and vapor migration in the two salt types chosen for the experiments: (1) pure salt, for its characteristics similar to the salt that might occur in potential US repositories, and (2) transitional salt, for its similarity to the salt that might occur in potential repositories in Germany

  13. Polymeric salt bridges for conducting electric current in microfluidic devices

    Science.gov (United States)

    Shepodd, Timothy J [Livermore, CA; Tichenor, Mark S [San Diego, CA; Artau, Alexander [Humacao, PR

    2009-11-17

    A "cast-in-place" monolithic microporous polymer salt bridge for conducting electrical current in microfluidic devices, and methods for manufacture thereof is disclosed. Polymeric salt bridges are formed in place in capillaries or microchannels. Formulations are prepared with monomer, suitable cross-linkers, solvent, and a thermal or radiation responsive initiator. The formulation is placed in a desired location and then suitable radiation such as UV light is used to polymerize the salt bridge within a desired structural location. Embodiments are provided wherein the polymeric salt bridges have sufficient porosity to allow ionic migration without bulk flow of solvents therethrough. The salt bridges form barriers that seal against fluid pressures in excess of 5000 pounds per square inch. The salt bridges can be formulated for carriage of suitable amperage at a desired voltage, and thus microfluidic devices using such salt bridges can be specifically constructed to meet selected analytical requirements.

  14. Fluid inclusions in salt: an annotated bibliography

    International Nuclear Information System (INIS)

    Isherwood, D.J.

    1979-01-01

    An annotated bibliography is presented which was compiled while searching the literature for information on fluid inclusions in salt for the Nuclear Regulatory Commission's study on the deep-geologic disposal of nuclear waste. The migration of fluid inclusions in a thermal gradient is a potential hazard to the safe disposal of nuclear waste in a salt repository. At the present time, a prediction as to whether this hazard precludes the use of salt for waste disposal can not be made. Limited data from the Salt-Vault in situ heater experiments in the early 1960's (Bradshaw and McClain, 1971) leave little doubt that fluid inclusions can migrate towards a heat source. In addition to the bibliography, there is a brief summary of the physical and chemical characteristics that together with the temperature of the waste will determine the chemical composition of the brine in contact with the waste canister, the rate of fluid migration, and the brine-canister-waste interactions

  15. Removal of uranium and salt from the Molten Salt Reactor Experiment

    International Nuclear Information System (INIS)

    Peretz, F.J.; Rushton, J.E.; Faulkner, R.L.; Walker, K.L.; Del Cul, G.D.

    1998-01-01

    In 1994, migration of 233 U was discovered to have occurred at the Molten Salt Reactor Experiment (MSRE) at Oak Ridge National Laboratory (ORNL). This paper describes the actions now underway to remove uranium from the off-gas piping and the charcoal bed, to remove and stabilize the salts, and to convert the uranium to a stable oxide for long-term storage

  16. Removal of uranium and salt from the Molten Salt Reactor Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Peretz, F.J.; Rushton, J.E.; Faulkner, R.L.; Walker, K.L.; Del Cul, G.D.

    1998-06-01

    In 1994, migration of {sup 233}U was discovered to have occurred at the Molten Salt Reactor Experiment (MSRE) at Oak Ridge National Laboratory (ORNL). This paper describes the actions now underway to remove uranium from the off-gas piping and the charcoal bed, to remove and stabilize the salts, and to convert the uranium to a stable oxide for long-term storage.

  17. Rheological stratification of the Hormuz Salt Formation in Iran - microstructural study of the dirty and pure rock salts from the Kuh-e-Namak (Dashti) salt diapir

    Science.gov (United States)

    Závada, Prokop; Desbois, Guillaume; Urai, Janos; Schulmann, Karel; Rahmati, Mahmoud; Lexa, Ondrej; Wollenberg, Uwe

    2014-05-01

    Significant viscosity contrasts displayed in flow structures of a mountain namakier (Kuh-e-Namak - Dashti), between 'weak' terrestrial debris bearing rock salt types and 'strong' pure rock salt types are questioned for deformation mechanisms using detailed quantitative microstructural study including crystallographic preferred orientation (CPO) mapping of halite grains. While the solid impurity rich ("dirty") rock salts contain disaggregated siltstone and dolomite interlayers, "clean" salts (debris free) reveal microscopic hematite and remnants of abundant fluid inclusions in non-recrystallized cores of porphyroclasts. Although flow in both, the recrystallized dirty and clean salt types is accommodated by combined mechanisms of pressure-solution creep (PS), grain boundary sliding (GBS) and dislocation creep accommodated grain boundary migration (GBM), their viscosity contrasts are explained by significantly slower rates of intergranular diffusion and piling up of dislocations at hematite inclusions in clean salt types. Porphyroclasts of clean salts deform by semi-brittle and plastic mechanisms with intra-crystalline damage being induced also by fluid inclusions that explode in the crystals at high fluid pressures. Boudins of clean salt types with coarse grained and original sedimentary microstructure suggest that clean rock salts are associated with dislocation creep dominated power law flow in the source layer and the diapiric stem. Rheological contrasts between both rock salt classes apply in general for the variegated and terrestrial debris rich ("dirty") Lower Hormuz and the "clean" rock salt forming the Upper Hormuz, respectively, and suggest that large strain rate gradients likely exist along horizons of mobilized salt types of different composition and microstructure.

  18. Mitochondrial membranes with mono- and divalent salt: Changes induced by salt ions on structure and dynamics

    NARCIS (Netherlands)

    Pöyry, S.; Róg, T.; Karttunen, M.E.J.; Vattulainen, I.

    2009-01-01

    We employ atomistic simulations to consider how mono- (NaCl) and divalent (CaCl2) salt affects properties of inner and outer membranes of mitochondria. We find that the influence of salt on structural properties is rather minute, only weakly affecting lipid packing, conformational ordering, and

  19. Capturing the age and spatial structures of migration

    NARCIS (Netherlands)

    Rogers, A; Raymer, J; Willekens, F

    In this paper we model the structures found in the level (generation) and allocation (distribution) components of age-specific and origin-destination-specific migration flows. For the examples, we examine the regional migration patterns in the USA for four periods: 1955-60, 1965-70, 1975-80, and

  20. Quarterly brine migration data report, May-September 1983: Nuclear Waste Repository simulation experiments (brine migration), Asse Mine of the Federal Republic of Germany

    International Nuclear Information System (INIS)

    Coyle, A.J.; Kalia, H.N.; Eckert, J.L.

    1987-04-01

    The first quarterly brine migration data report describes experiments simulating a nuclear waste repository at the 800-m (2624-ft) level of the Asse Salt Mine in the Federal Republic of Germany from May 1983 through September 1983. This report describes the test equipment, the Asse Salt Mine, and the pretest properties of the salt in the test gallery. This report also includes test data for the first 4 months of operations on brine migration rates, borehole pressure, salt temperatures, and thermomechanical behavior of the salt. The duration of the experiments will be approximately 2 years, ending in December 1985. 83 figs., 55 tabs

  1. Brine migration in hot-pressed polycrystalline sodium chloride

    International Nuclear Information System (INIS)

    Biggers, J.V.; Dayton, G.O.

    1982-12-01

    This report describes experiments designed to provide data on brine migration in polycrystalline salt. Polycrystalling samples of various grain sizes, density, and purity were prepared from several commercial-grade salts by hot-pressing. Three distinct experimental set-ups were used to place salt billets in an induced thermal gradient in contact with brine source. The test designs varied primarily in the way in which the thermal gradient was applied and monitored and the way in which brine migration was determined. All migration was in enclosed vessels which precluded visual observation of brine movement through the microstructure. Migration velocities were estimated either by the timed appearance of brine at the hot face of the sample, or by determination of the penetration distance of migration artifacts in the microstructure after tests of fixed duration. For various reasons both of these methods were subject to a large degree of error. Our results suggest, however, that the migration velocity in dense polycrystalline salt may be at least an order of magnitude greater than that suggested by single-crystal experiments. Microstructural analysis shows that brine prefers to migrate along paths of high crystalline activity such as grain and subgrain boundaries and is dispersed rather quickly in the microstructure. A series of tests were performed using various types of tracers in brine in order to flag migration paths and locate brine in the microstructure more decisively. These attempts failed and it appears that only the aqueous portion of the brine moves through the microstructure with the dissolved ions being lost and replaced rather quickly. This suggests the use of deuterium as a tracer in future work

  2. A systematic technique for the sequential restoration of salt structures

    Science.gov (United States)

    Rowan, Mark G.

    1993-12-01

    A method is described for the sequential restoration of cross sections in areas of salt tectonics where deformation is confined to the salt and higher layers. The subsurface geometry evolves with time through the interaction of various processes: sedimentation, compaction, isostatic adjustment, thermal subsidence (if present), faulting, and salt withdrawal/ diapirism. The technique systematically calculates and removes the effects of each of these processes during specified time intervals defined by the interpreted horizons. It makes no assumptions about salt kinematics and generally results in the area of the salt layer changing through time. The method is described for restoration of extensional terranes, but it is also suitable for areas of contractional salt tectonics with only minor modifications. After converting an interpreted seismic profile to depth, the top layer is stripped off and the underlying section is decompacted according to standard porosity-depth functions. A deep baseline, unaffected by compaction or deformation, is used to restore any isostatic compensation or thermal subsidence. Isostasy is calculated according to the Airy model, and differential sedimentary loading across a section is shown to be approximately balanced by changes in salt thickness so that the load is evenly distributed. After these processes have been reversed, the resulting geometry and the seismic data are used to create the sea-floor template for structural restoration. Fault offsets are removed and the layers down to the top salt are restored to this template, while the base salt remains fixed. The resulting space between the restored top salt and the fixed base salt defines the restored salt geometry. In addition, the difference between the sea-floor template and a fixed sea level provides a measure of the change in water depth (ignoring eustatic changes in sea level). The technique is applied to an interpreted seismic profile from the eastern Green Canyon/Ewing Bank

  3. Structural and physicochemical characterization of pyridine derivative salts of anti-inflammatory drugs

    Science.gov (United States)

    Nechipadappu, Sunil Kumar; Trivedi, Darshak R.

    2017-08-01

    Salts of common anti-inflammatory drugs mefenamic acid (MFA), tolfenamic acid (TFA) and naproxen (NPX) with various pyridine derivatives (4-amino pyridine (4AP), 4-dimethylaminopyridine (DMAP) and 2-amino pyridine (2AP)) were synthesized by crystal engineering approach based on the pKa values of API's and the salt former. All the salts were characterized systematically by various spectroscopic methods including FT-IR and 1H NMR and the crystal structure was determined by single-crystal X-ray diffraction techniques (SCXRD). DMAP salt of NPX and 2AP salts of MFA and TFA were not obtained in the salt screening experiments. All the molecular salts exhibited 1:1 molecular stoichiometry in the asymmetric unit and except NPX-2AP salt, all the molecular salts included a water molecule in the crystal lattice. Physicochemical and structural properties between drug-drug molecular salts of MFA-4AP, TFA-4AP and NPX-4AP have been evaluated and it was found that these molecular salts were found to be stable for a time period of six months at ambient condition and further hydration of molecular salts were not observed even at accelerated humid conditions (∼75% RH). It was found that 4AP salts of MFA and TFA and DMAP salts of MFA and TFA are isostructural.

  4. Structural testing of salt loaded HEPA filters for WIPP

    International Nuclear Information System (INIS)

    Smith, P.R.; Leslie, I.H.; Hensel, E.C.; Shultheis, T.M.; Walls, J.R.

    1993-01-01

    The ventilation studies of the Waste Isolation Pilot Plant described in this paper were performed by personnel from New Mexico State Univ. in collaboration with Sandia National Laboratories, Los Alamos National Laboratory and Westinghouse Corporation. High efficiency particulate air filters (0.61m by 0.61m by 0.3m) of the type in use at the Waste Isolation Pilot Plant were loaded with salt aerosol provided from that site. The structural strength of salt-loaded, high-efficiency filters was investigated at two humidity levels, high (75%RH) and low (13-14% RH), by subjecting the filters to pressure transients of the types expected from tornadoes. Filters loaded under the high humidity condition proved to have a greater structural strength than did the filters loaded under the low humidity conditions, when both types were subjected to tornado-like pressure pulses. This unexpected results was apparently due to the crystallization of salt upon the wire face guard of the HEPA filter loaded under the high humidity condition which kept salt from penetrating the filter medium while still providing a substantial pressure drop at the standard flow rate. Results are also presented for HEPA filters pre-conditioned at 100% RH before structural testing and for HEPA filters in series with pre-filters

  5. Rating Migration and Bond Valuation: Decomposing Rating Migration Matrices from Market Data via Default Probability Term Structures

    Directory of Open Access Journals (Sweden)

    Brian BARNARD

    2017-09-01

    Full Text Available The study builds on previous research that decomposes rating category default probability term structures from rating category interest rate term structures, and proposes a method to decompose rating migration matrices from market data, via decomposed default probability term structures. To investigate the power and accuracy of the proposed method, it was examined to what extent an existing, known rating migration matrix could again be surfaced by the method. Overall, the results are more than satisfactory, and the method promises to be accurate. Although not considered here, the main objective is the application of the method to market data. The outcome should be insightful in itself, and can be used to evaluate historical rating migration matrices commonly devised by rating agencies, and to form a better understanding of the default probability term structures embedded in market data.

  6. Purification of specific structured lipids by distillation: Effects on acyl migration

    DEFF Research Database (Denmark)

    Xu, Xuebing; Skands, A.; Adler-Nissen, Jens

    2001-01-01

    The cause and effects of acyl migration during the purification of specific structured lipids by distillation were studied in a conventional batch deodorizer with stripping steam. The mixture of specific structured lipids produced by lipase-catalyzed acidolysis between rapeseed oil and capric acid...... influenced the rate of acyl migration, and their combinations made the effect more severe. However, diacylglycerols were found to be the main reason for acyl migration. In the distillation of the specific structured lipid product mixture, distillation temperature and time were the main factors to determine...... the degree of acyl migration and the extent of separation of free fatty acids. The results indicate that more efficient separation technology should be used to improve the quality of the purified structured lipids. in order to reduce the distillation temperature, vacuum should be made as low as possible...

  7. Hydroxyl migration disorders the surface structure of hydroxyapatite nanoparticles

    Science.gov (United States)

    Cheng, Xiajie; Wu, Hong; Zhang, Li; Ma, Xingtao; Zhang, Xingdong; Yang, Mingli

    2017-09-01

    The surface structure of nano-hydroxyapatite (HAP) was investigated using a combined simulated annealing and molecular dynamics method. The stationary structures of nano-HAP with 4-7 nm in diameter and annealed under different temperatures were analyzed in terms of pair distribution function, structural factor, mean square displacement and atomic coordination number. The particles possess different structures from bulk crystal. A clear radial change in their atomic arrangements was noted. From core to surface the structures change from ordered to disordered. A three-shell model was proposed to describe the structure evolution of nano-HAP. Atoms in the core zone keep their arrangements as in crystal, while atoms in the surface shell are in short-range order and long-range disorder, adopting a typically amorphous structure. Atoms in the middle shell have small displacements and/or deflections but basically retain their original locations as in crystal. The disordered shell is about 1 nm in thickness, in agreement with experimental observations. The disordering mainly stems from hydroxyl migration during which hydroxyls move to the surface and bond with the exposed Ca ions, and their left vacancies bring about a rearrangement of nearby atoms. The disordering is to some extent different for particles unannealed under different temperatures, resulting from fewer number of migrated hydroxyls at lower temperatures. Particles with different sizes have similar surface structures, and their surface energy decreases with increasing size. Moreover, the surface energy is reduced by hydroxyl migration because the exposed Ca ions on the surface are ionically bonded with the migrated hydroxyls. Our calculations proposed a new structure model for nano-HAP, which indicates a surface structure with activities different from those without surface reorganization. This is particularly interesting because most bioactivities of biomaterials are dominated by their surface activity.

  8. Salt Damage and Rising Damp Treatment in Building Structures

    Directory of Open Access Journals (Sweden)

    J. M. P. Q. Delgado

    2016-01-01

    Full Text Available Salt damage can affect the service life of numerous building structures, both historical and contemporary, in a significant way. In this review, various damage mechanisms to porous building materials induced by salt action are analyzed. The importance of pretreatment investigations is discussed as well; in combination with the knowledge of salt and moisture transport mechanisms they can give useful indications regarding treatment options. The methods of salt damage treatment are assessed then, including both passive techniques based on environmental control, reduction of water transport, or conversion to less soluble salts and active procedures resulting in the removal of salts from deterioration zones. It is concluded that cellulose can still be considered as the favorite material presently used in desalination poultices but hydrophilic mineral wool can serve as its prospective alternative in future applications. Another important cause of building pathologies is the rising damp and, in this phenomenon, it is particularly severe considering the presence of salts in water. The treatment of rising damp in historic building walls is a very complex procedure and at Laboratory of Building Physics (LFC-FEUP a wall base hygroregulated ventilation system was developed and patented.

  9. Nuclear waste repository simulation experiments (brine migration), Asse Mine of the Federal of Germany: Quarterly brine migration data report, July-September 1984

    International Nuclear Information System (INIS)

    Coyle, A.J.; Kalia, H.N.; Eckert, J.L.

    1986-10-01

    The fifth brine migration data status report describes experiments simulating a nuclear waste repository at the 800-m (2624-ft) level of the Asse Salt Mine in the Federal Republic of Germany from May 1983 through September 1984. This report describes the test equipment, the Asse Salt Mine, and the pretest properties of the salt in the test gallery. This report also includes test data for the first 16 months of operations on brine migration rates, borehole pressure, salt temperatures, and thermomechanical behavior of the salt. Annual reports have been prepared for the years 1983 and 1984, describing the test activities on a yearly basis (Rothfuchs et al., 1984, 1986). The duration of the experiments will be approximately 2 years, ending in December 1985. 2 refs., 118 figs., 91 tabs

  10. Aspects on the gas generation and migration in repositories for high level waste in salt formations

    International Nuclear Information System (INIS)

    Ruebel, Andre; Buhmann, Dieter; Meleshyn, Artur; Moenig, Joerg; Spiessl, Sabine

    2013-07-01

    In a deep geological repository for high-level waste, gases may be produced during the post-closure phase by several processes. The generated gases can potentially affect safety relevant features and processes of the repository, like the barrier integrity, the transport of liquids and gases in the repository and the release of gaseous radionuclides from the repository into the biosphere. German long-term safety assessments for repositories for high-level waste in salt which were performed prior 2010 did not explicitly consider gas transport and the consequences from release of volatile radionuclides. Selected aspects of the generation and migration of gases in repositories for high-level waste in a salt formation are studied in this report from the viewpoint of the performance assessment. The knowledge on the availability of water in the repository, in particular the migration of salt rock internal fluids in the temperature field of the radioactive waste repository towards the emplacement drifts, was compiled and the amount of water was roughly estimated. Two other processes studied in this report are on the one hand the release of gaseous radionuclides from the repository and their potential impact in the biosphere and on the other hand the transport of gases along the drifts and shafts of the repository and their interaction with the fluid flow. The results presented show that there is some gas production expected to occur in the repository due to corrosion of container material from water disposed of with the backfill and inflowing from the host rock during the thermal phase. If not dedicated gas storage areas are foreseen in the repository concept, these gases might exceed the storage capacity for gases in the repository. Consequently, an outflow of gases from the repository could occur. If there are failed containers for spent fuel, radioactive gases might be released from the containers into the gas space of the backfill and subsequently transported together

  11. Expected brine movement at potential nuclear waste repository salt sites

    International Nuclear Information System (INIS)

    McCauley, V.S.; Raines, G.E.

    1987-08-01

    The BRINEMIG brine migration code predicts rates and quantities of brine migration to a waste package emplaced in a high-level nuclear waste repository in salt. The BRINEMIG code is an explicit time-marching finite-difference code that solves a mass balance equation and uses the Jenks equation to predict velocities of brine migration. Predictions were made for the seven potentially acceptable salt sites under consideration as locations for the first US high-level nuclear waste repository. Predicted total quantities of accumulated brine were on the order of 1 m 3 brine per waste package or less. Less brine accumulation is expected at domal salt sites because of the lower initial moisture contents relative to bedded salt sites. Less total accumulation of brine is predicted for spent fuel than for commercial high-level waste because of the lower temperatures generated by spent fuel. 11 refs., 36 figs., 29 tabs

  12. Salt-occluded zeolite waste forms: Crystal structures and transformability

    International Nuclear Information System (INIS)

    Richardson, J.W. Jr.

    1996-01-01

    Neutron diffraction studies of salt-occluded zeolite and zeolite/glass composite samples, simulating nuclear waste forms loaded with fission products, have revealed complex structures, with cations assuming the dual roles of charge compensation and occlusion (cluster formation). These clusters roughly fill the 6--8 angstrom diameter pores of the zeolites. Samples are prepared by equilibrating zeolite-A with complex molten Li, K, Cs, Sr, Ba, Y chloride salts, with compositions representative of anticipated waste systems. Samples prepared using zeolite 4A (which contains exclusively sodium cations) as starting material are observed to transform to sodalite, a denser aluminosilicate framework structure, while those prepared using zeolite 5A (sodium and calcium ions) more readily retain the zeolite-A structure. Because the sodalite framework pores are much smaller than those of zeolite-A, clusters are smaller and more rigorously confined, with a correspondingly lower capacity for waste containment. Details of the sodalite structures resulting from transformation of zeolite-A depend upon the precise composition of the original mixture. The enhanced resistance of salt-occluded zeolites prepared from zeolite 5A to sodalite transformation is thought to be related to differences in the complex chloride clusters present in these zeolite mixtures. Data relating processing conditions to resulting zeolite composition and structure can be used in the selection of processing parameters which lead to optimal waste forms

  13. Imaging of salt structure; Gan`enso kozo no imaging

    Energy Technology Data Exchange (ETDEWEB)

    Akama, K; Saeki, T [Japan National Corp., Tokyo (Japan). Technology Research Center; Matsuoka, T [Japan Petroleum Exploration Corp., Tokyo (Japan)

    1996-10-01

    Due to the improvement of algorithm and the advancement of calculation performance, the imaging by depth migration before stacking is being put into practice from the viewpoint of both calculation cost and accuracy. A lot of imaging examples have been already reported from the survey areas with complicated velocity structures, such as the North Sea and the Gulf of Mexico. Effectiveness of the method has been confirmed. For imaging techniques in Japan National Oil Corporation and Japan Petroleum Exploration Co., Ltd., high-speed depth migration before stacking and high efficiency velocity structure estimation technique have been investigated. This paper describes necessary care to be taken when using depth focusing analysis (DFA) for correcting a velocity model, as an interim stage of case study. The results of depth migration before stacking using dip moveout (DMO) velocity were further inferior to the section obtained by the migration after tracking. Tendency of velocity errors was distinctly deviated with the variation of depth and horizontal position. It was not suitable for modifying the velocity model using DFA. 4 refs., 4 figs.

  14. Features of geologic structure of 'Lira' object territory and possible radionuclide migration pathways

    International Nuclear Information System (INIS)

    Belyashov, D.N.; Mokhov, V.A.; Melent'ev, M.I.; Kislyj, B.I.

    1999-01-01

    In the upper part of Karachaganak salt couple on the Lira object there are 6 artificially created chambers designed for gas condensate store at the depth 850-900 m. The chambers were created with help of underground nuclear explosions. At present a general assessment of radionuclide migration pathways from underground points of an explosion on the surrounding territories in the Lira vicinage is done. On the basis of analysis of geological and hydrogeological data by the Lira area the 4 stratigraphical and hypsometric level of possible radionuclide migration pathways could be marked out. The first of these levels related with Upper Permian saliferous sediments and it covers depths about 1 km up to couple roofing. Here the radionuclide migration will take part by tectonic breaks and fractured reservoirs, activated by energies of conducted explosions. Higher stratigraphic and hypsometric levels have been related with sediments of trias, Jurassic and partially of Cretaceous (second level), pliocene and pliocene-under Quaternary age (third level) and Quaternary sediments of Ural, Ilek and Berezovka rivers terraces (fourth level) where it is possible considerable lateral radionuclide migration in the northern and southern directions toward the couple's framing carvings

  15. Mechanical structure and problem of thorium molten salt reactor

    International Nuclear Information System (INIS)

    Kamei, Takashi

    2011-01-01

    After Fukushima Daiichi accident, there became great interest in Thorium Molten Salt Reactor (MSR) for the safety as station blackout leading to auto drainage of molten salts with freeze valve. This article described mechanical structure of MSR and problems of materials and pipes. Material corrosion problem by molten salts would be solved using modified Hastelloy N with Ti and Nb added, which should be confirmed by operation of an experimental reactor. Trends in international activities of MSR were also referred including China declaring MSR development in January 2011 to solve thorium contamination issues at rare earth production and India rich in thorium resources. (T. Tanaka)

  16. Impact of solid second phases on deformation mechanisms of naturally deformed salt rocks (Kuh-e-Namak, Dashti, Iran) and rheological stratification of the Hormuz Salt Formation

    Science.gov (United States)

    Závada, P.; Desbois, G.; Urai, J. L.; Schulmann, K.; Rahmati, M.; Lexa, O.; Wollenberg, U.

    2015-05-01

    Viscosity contrasts displayed in flow structures of a mountain namakier (Kuh-e-Namak - Dashti), between 'weak' second phase bearing rock salt and 'strong' pure rock salt types are studied for deformation mechanisms using detailed quantitative microstructural study. While the solid inclusions rich ("dirty") rock salts contain disaggregated siltstone and dolomite interlayers, "clean" salts reveal microscopic hematite and remnants of abundant fluid inclusions in non-recrystallized cores of porphyroclasts. Although the flow in both, the recrystallized "dirty" and "clean" salt types is accommodated by combined mechanisms of pressure-solution creep (PS), grain boundary sliding (GBS), transgranular microcracking and dislocation creep accommodated grain boundary migration (GBM), their viscosity contrasts observed in the field outcrops are explained by: 1) enhanced ductility of "dirty" salts due to increased diffusion rates along the solid inclusion-halite contacts than along halite-halite contacts, and 2) slow rates of intergranular diffusion due to dissolved iron and inhibited dislocation creep due to hematite inclusions for "clean" salt types Rheological contrasts inferred by microstructural analysis between both salt rock classes apply in general for the "dirty" salt forming Lower Hormuz and the "clean" salt forming the Upper Hormuz of the Hormuz Formation and imply strain rate gradients or decoupling along horizons of mobilized salt types of different composition and microstructure.

  17. Ion diffusion related to structure in molten salts

    International Nuclear Information System (INIS)

    Tosi, M.P.

    1996-08-01

    A model first developed by Zwanzig to derive transport coefficients in cold dense fluids directly from the Green-Kubo time correlation formulae allows one to relate macroscopic diffusion coefficients to the local fluid structure. Applications to various ionic diffusion processes in molten salts are reviewed. Consequences of partial structural quenching are also discussed. (author). 28 refs, 3 tabs

  18. Modeling internal deformation of salt structures targeted for radioactive waste disposal

    International Nuclear Information System (INIS)

    Chemia, Zurab

    2008-01-01

    This thesis uses results of systematic numerical models to argue that externally inactive salt structures, which are potential targets for radioactive waste disposal, might be internally active due to the presence of dense layers or blocks within a salt layer. The three papers that support this thesis use the Gorleben salt diapir (NW Germany), which was targeted as a future final repository for high-grade radioactive waste, as a general guideline. The first two papers present systematic studies of the parameters that control the development of a salt diapir and how it entrains a dense anhydrite layer. Results from these numerical models show that the entrainment of a dense anhydrite layer within a salt diapir depends on four parameters: sedimentation rate, viscosity of salt, perturbation width and the stratigraphic location of the dense layer. The combined effect of these four parameters, which has a direct impact on the rate of salt supply (volume/area of the salt that is supplied to the diapir with time), shape a diapir and the mode of entrainment. Salt diapirs down-built with sedimentary units of high viscosity can potentially grow with an embedded anhydrite layer and deplete their source layer (salt supply ceases). However, when salt supply decreases dramatically or ceases entirely, the entrained anhydrite layer/segments start to sink within the diapir. In inactive diapirs, sinking of the entrained anhydrite layer is inevitable and strongly depends on the rheology of the salt, which is in direct contact with the anhydrite layer. During the post-depositional stage, if the effective viscosity of salt falls below the threshold value of around 10 18 -10 19 Pa s, the mobility of anhydrite blocks might influence any repository within the diapir. However, the internal deformation of the salt diapir by the descending blocks decreases with increase in effective viscosity of salt. The results presented in this thesis suggest that it is highly likely that salt structures

  19. A model describing water and salt migration in concrete during wetting/drying cycles

    NARCIS (Netherlands)

    Arends, T.; Taher, A.; van der Zanden, A.J.J.; Brouwers, H.J.H.; Bilek, V.; Kersner, Z.

    2014-01-01

    In order to predict the life span of concrete structures, models describing the migration of chloride are needed. In this paper, a start is made with a simple, theoretical model describing water and chloride transport in a concrete sample. First, transport of water in concrete is considered with

  20. In situ brine migration experiments at the Avery Island salt mine

    International Nuclear Information System (INIS)

    Krause, W.B.; Van Sambeek, L.L.; Stickney, R.G.

    1980-01-01

    An in situ brine movement study was conducted at the Avery Island Salt Mine of the International Salt Company in southwestern Louisiana. The objective of the in situ experiments was to relate field measurements to previously determined laboratory and analytical results for the purpose of determining the rate and amount of brine movement through dome salt when subjected to heating. The heating in the experiments was provided by electrical heaters emplaced in the salt mine floor. An understanding of thermally induced brine movement is essential from the standpoint of identifying conditions which may influence the physical integrity of the nuclear waste canisters or impede the functional performance of the waste package system in a nuclear waste repository in geologic salt. 28 refs

  1. Fluid and ionic transport properties of deformed salt rock

    International Nuclear Information System (INIS)

    Peach, C.J.; Spiers, C.J.; Tankink, A.J.; Zwart, H.J.

    1987-01-01

    This is a final report on work done on the transport properties of salt during the period 1 January 1984 to 30 June 1985. This work was directed largely at the measurement of creep-induced permeability in salt rock, at determining the permeability persistence/decay characteristics of creep-dilated salt rock under hydrostatic conditions, and at ion migration/retention experiments on both deformed and undeformed material. The permeability work was carried out using both gas (argon) and brine, and involved the design and construction of corresponding permeametry systems for use in conjunction with dilatometric triaxial testing apparatus. Ion migration/retention studies involved the use of contaminant species such as Sr 2+ , Cs + , Fe 3+ and TcO 4

  2. Application of Post-stack migration to seismic data associated with fault structures

    Science.gov (United States)

    Koduru, Anitha; Mohanty, P. R.

    2015-06-01

    In hydrocarbon exploration, wave-equation migration techniques play an important role in imaging the complex geological structures. Usually, post-stack migration scheme is applied to the seismic data to improve the resolution with restoration of dipping reflectors to their true position. As a result, the migrated time sections are interpretable in terms of subsurface features. As a numerical study, three fault models are considered for the present study. First of all, synthetic time sections are generated corresponding to three models. Later, post stack migration schemes such as Gazdag(PS), Phase-shift with turning rays and reverse time migration (T-K) domain techniques are applied in order to judge the imaging accuracy, preservation of true amplitude and computational speed. All the three post stack time migrated sections delineate the structure with their throw.However, the reverse time migrations (T-K) clearly delineate the reflectors in restoring the throw properly with minimum computational time. In order to test the validity the numerical results, similar exercise has been undertaken using field seismic data of KG basin, India. The results indicates that the field migrated sections are imaged. But, the reverse time migration (T-K ) provides the best subsurface image with restoration of reflectors and collapse of diffracted events with least computational time. Gazdag (PS) and Phase-Shift with turning migrated section shows the reduction of amplitude whereas, the reverse time migration preserved the amplitude fully.

  3. Estimating Rheological Parameters of Anhydrite from Folded Evaporite sequences: Implications for Internal Dynamics of Salt Structure

    Science.gov (United States)

    Adamuszek, Marta; Dabrowski, Marcin; Schmalholz, Stefan M.; Urai, Janos L.; Raith, Alexander

    2015-04-01

    Salt structures have been identified as a potential target for hydrocarbon, CO2, or radioactive waste storage. The most suitable locations for magazines are considered in the thick and relatively homogeneous rock salt layers. However, salt structures often consist of the evaporite sequence including rock salt intercalated with other rock types e.g.: anhydrite, gypsum, potassium and magnesium salt, calcite, dolomite, or shale. The presence of such heterogeneities causes a serious disturbance in the structure management. Detailed analysis of the internal architecture and internal dynamics of the salt structure are crucial for evaluating them as suitable repositories and also their long-term stability. The goal of this study is to analyse the influence of the presence of anhydrite layers on the internal dynamics of salt structures. Anhydrite is a common rock in evaporite sequences. Its physical and mechanical properties strongly differ from the properties of rock salt. The density of anhydrite is much higher than the density of salt, thus anhydrite is likely to sink in salt causing the disturbance of the surrounding structures. This suggestion was the starting point to the discussion about the long-term stability of the magazines in salt structures [1]. However, the other important parameter that has to be taken into account is the viscosity of anhydrite. The high viscosity ratio between salt and anhydrite can restrain the layer from sinking. The rheological behaviour of anhydrite has been studied in laboratory experiments [2], but the results only provide information about the short-term behaviour. The long-term behaviour can be best predicted using indirect methods e.g. based on the analysis of natural structures that developed over geological time scale. One of the most promising are fold structures, the shape of which is very sensitive to the rheological parameters of the deforming materials. Folds can develop in mechanically stratified materials during layer

  4. Impact on breeding rate of different Molten Salt reactor core structures

    International Nuclear Information System (INIS)

    Wang Haiwei; Mei Longwei; Cai Xiangzhou; Chen Jingen; Guo Wei; Jiang Dazhen

    2013-01-01

    Background: Molten Salt Reactor (MSR) has several advantages over the other Generation IV reactor. Referred to the French CNRS research and compared to the fast reactor, super epithermal neutron spectrum reactor type is slightly lower and beading rate reaches 1.002. Purpose: The aim is to explore the best conversion zone layout scheme in the super epithermal neutron spectrum reactor. This study can make nuclear fuel as one way to solve the energy problems of mankind in future. Methods: Firstly, SCALE program is used for molten salt reactor graphite channel, molten salt core structure, control rods, graphite reflector and layer cladding structure. And the SMART modules are used to record the important actinides isotopes and their related reaction values of each reaction channel. Secondly, the thorium-uranium conversion rate is calculated. Finally, the better molten salt reactor core optimum layout scheme is studied comparing with various beading rates. Results: Breading zone layout scheme has an important influence on the breading rate of MSR. Central graphite channels in the core can get higher neutron flux irradiation. And more 233 Th can convert to 233 Pa, which then undergoes beta decay to become 233 U. The graphite in the breading zone gets much lower neutron flux irradiation, so the life span of this graphite can be much longer than that of others. Because neutron flux irradiation in the uranium molten salt graphite has nearly 10 times higher than the graphite in the breading zone, it has great impact on the thorium-uranium conversion rates. For the super epithermal neutron spectrum molten salt reactors, double salt design cannot get higher thorium-uranium conversion rates. The single molten salt can get the same thorium-uranium conversion rate, meanwhile it can greatly extend the life of graphite in the core. Conclusions: From the analysis of calculation results, Blanket breeding area in different locations in the core can change the breeding rates of thorium

  5. International cross-border migration in the South-East Baltic: factors, structure, consequences

    Directory of Open Access Journals (Sweden)

    Yemelyanova Larisa

    2010-12-01

    Full Text Available This article presents the results of an integrated research encompassing both the study of migration processes in the South-East Baltic (volume, structure, directions and the analysis of factors affecting migration mobility of the population as well as the assessment of migration influence on the socioeconomic development of three border territories.

  6. Morphology and anatomical structure of the larval salt gland of ...

    African Journals Online (AJOL)

    Ezedom Theresa

    2013-10-09

    Oct 9, 2013 ... the morphology and fine structure of the ion transporting epithelium ... The general structure of the salt gland of nauplii cultured at 180 g/L disappeared. ...... Wu G, Zhang H, Sun J, Liu F, Ge X, Chen WH, Yu, J, Wang W (2011).

  7. The possibilities of least-squares migration of internally scattered seismic energy

    KAUST Repository

    Aldawood, Ali

    2015-05-26

    Approximate images of the earth’s subsurface structures are usually obtained by migrating surface seismic data. Least-squares migration, under the single-scattering assumption, is used as an iterative linearized inversion scheme to suppress migration artifacts, deconvolve the source signature, mitigate the acquisition fingerprint, and enhance the spatial resolution of migrated images. The problem with least-squares migration of primaries, however, is that it may not be able to enhance events that are mainly illuminated by internal multiples, such as vertical and nearly vertical faults or salt flanks. To alleviate this problem, we adopted a linearized inversion framework to migrate internally scattered energy. We apply the least-squares migration of first-order internal multiples to image subsurface vertical fault planes. Tests on synthetic data demonstrated the ability of the proposed method to resolve vertical fault planes, which are poorly illuminated by the least-squares migration of primaries only. The proposed scheme is robust in the presence of white Gaussian observational noise and in the case of imaging the fault planes using inaccurate migration velocities. Our results suggested that the proposed least-squares imaging, under the double-scattering assumption, still retrieved the vertical fault planes when imaging the scattered data despite a slight defocusing of these events due to the presence of noise or velocity errors.

  8. The possibilities of least-squares migration of internally scattered seismic energy

    KAUST Repository

    Aldawood, Ali; Hoteit, Ibrahim; Zuberi, Mohammad; Turkiyyah, George; Alkhalifah, Tariq Ali

    2015-01-01

    Approximate images of the earth’s subsurface structures are usually obtained by migrating surface seismic data. Least-squares migration, under the single-scattering assumption, is used as an iterative linearized inversion scheme to suppress migration artifacts, deconvolve the source signature, mitigate the acquisition fingerprint, and enhance the spatial resolution of migrated images. The problem with least-squares migration of primaries, however, is that it may not be able to enhance events that are mainly illuminated by internal multiples, such as vertical and nearly vertical faults or salt flanks. To alleviate this problem, we adopted a linearized inversion framework to migrate internally scattered energy. We apply the least-squares migration of first-order internal multiples to image subsurface vertical fault planes. Tests on synthetic data demonstrated the ability of the proposed method to resolve vertical fault planes, which are poorly illuminated by the least-squares migration of primaries only. The proposed scheme is robust in the presence of white Gaussian observational noise and in the case of imaging the fault planes using inaccurate migration velocities. Our results suggested that the proposed least-squares imaging, under the double-scattering assumption, still retrieved the vertical fault planes when imaging the scattered data despite a slight defocusing of these events due to the presence of noise or velocity errors.

  9. Salt effect on physiological, biochemical and anatomical structures ...

    African Journals Online (AJOL)

    In this study, we evaluated the salt concentration effect on plant growth, mineral composition, antioxidant responses and anatomical structure of two varieties of Origanum majorana after exposure to NaCl treatment. Our results show an inclusive behaviour of the two varieties, since the majority of sodium was exported and ...

  10. A study on the structure of thorium salt solutions

    International Nuclear Information System (INIS)

    Magini, M.; Cabrini, A.; Di Bartolomeo, A.

    1975-01-01

    The structure of highly hydrolyzed thorium salt solutions has been investigated by large and small angle X-ray scattering techniques. The diffraction data obtained with large angle measurements show the presence in solution of microcrystalline particles with the thorium oxide structure. Particles larger than those were discovered by small angle measurements. A possible shape of these colloidal particles has been discussed

  11. The effect of migration on family structures in sub-Saharan Africa.

    Science.gov (United States)

    Okoth-ogendo, H W

    1989-06-01

    This paper assesses the effect of migration or family structures in sub-Saharan Africa, especially the effect of emigration on the reproduction, production, and social stability of the family in areas of origin in the predominantly agrarian communities of East and Southern Africa. Migration in precolonial Africa usually occurred for 1 of the following reasons: 1) the search by communities for new habitats and opportunities; 2) as a community response to droughts, floods, environmental degradation, and similar disasters; and 3) as a result of internecine wars, civil strife, and general hostilities. Thus, because of the collective nature of early migrations, the family unit maintained a much greater degree of social cohesion. The effects of the rise of the modern state in Africa on migration include 1) spatial limits of collective migration were frozen, 2) the colonial boundaries did not always correspond to cultural divisions, 3) both migration within colonial boundaries and individual migration became dominant, and 4) cyclical migration began. The end of colonialism resulted in 1) difficulties in creating strong and internally coherent nation states because of the uncertainty of national borders and 2) more cyclical migrants. The effects of migration on reproduction in the family during the colonial period include 17 extremely low fertility rates, 2) widespread domestic instability, and 3) exacerbation of moral decadence. Contemporary patterns of emigration have been far less disruptive, due in part to increased personal mobility and migration of the complete reproductive unit. The effects of migration on production include 1) depletion of labor for production; 2) women had to assume production functions, together with all their other responsibilities; and 3) very little cash or goods were available for remittance to areas of origin. Production and productivity among rural African families will continue to suffer as long as plantations, mines, and urban centers

  12. Mitochondrial membranes with mono- and divalent salt: changes induced by salt ions on structure and dynamics

    DEFF Research Database (Denmark)

    Pöyry, Sanja; Róg, Tomasz; Karttunen, Mikko

    2009-01-01

    We employ atomistic simulations to consider how mono- (NaCl) and divalent (CaCl(2)) salt affects properties of inner and outer membranes of mitochondria. We find that the influence of salt on structural properties is rather minute, only weakly affecting lipid packing, conformational ordering......, and membrane electrostatic potential. The changes induced by salt are more prominent in dynamical properties related to ion binding and formation of ion-lipid complexes and lipid aggregates, as rotational diffusion of lipids is slowed down by ions, especially in the case of CaCl(2). In the same spirit, lateral...... diffusion of lipids is slowed down rather considerably for increasing concentration of CaCl(2). Both findings for dynamic properties can be traced to the binding of ions with lipid head groups and the related changes in interaction patterns in the headgroup region, where the binding of Na(+) and Ca(2+) ions...

  13. Evaluation of aluminum migration into foodstuffs from aluminium cookware

    Directory of Open Access Journals (Sweden)

    M Radi

    2014-05-01

    Full Text Available Nowadays, the existence of aluminum in human diet as a food contaminant has attracted the concerns of many researchers. It seems that the cooking pans are common sources of aluminum exposure through foodstuffs in Iran. The aim of this study was to evaluate the migration of aluminum from cooking containers into foodstuffs. For this purpose, solutions with different concentrations of citric acid, sodium chloride, fat, protein and sugar were prepared and migration of aluminum into these solutions was measured using atomic absorption spectrometry. Results showed that salt and citric acid concentrations could enhance aluminum migration; whereas, acid concentration was more effective than salt due to its corrosive effect. The intensity of heat processing and the duration of heat treatment had direct relation with aluminum migration. The aluminum content of cooked foods in aluminum cooking pans was also significantly more than control samples.

  14. Agent-Based Modeling of China's Rural-Urban Migration and Social Network Structure.

    Science.gov (United States)

    Fu, Zhaohao; Hao, Lingxin

    2018-01-15

    We analyze China's rural-urban migration and endogenous social network structures using agent-based modeling. The agents from census micro data are located in their rural origin with an empirical-estimated prior propensity to move. The population-scale social network is a hybrid one, combining observed family ties and locations of the origin with a parameter space calibrated from census, survey and aggregate data and sampled using a stepwise Latin Hypercube Sampling method. At monthly intervals, some agents migrate and these migratory acts change the social network by turning within-nonmigrant connections to between-migrant-nonmigrant connections, turning local connections to nonlocal connections, and adding among-migrant connections. In turn, the changing social network structure updates migratory propensities of those well-connected nonmigrants who become more likely to move. These two processes iterate over time. Using a core-periphery method developed from the k -core decomposition method, we identify and quantify the network structural changes and map these changes with the migration acceleration patterns. We conclude that network structural changes are essential for explaining migration acceleration observed in China during the 1995-2000 period.

  15. Agent-based modeling of China's rural-urban migration and social network structure

    Science.gov (United States)

    Fu, Zhaohao; Hao, Lingxin

    2018-01-01

    We analyze China's rural-urban migration and endogenous social network structures using agent-based modeling. The agents from census micro data are located in their rural origin with an empirical-estimated prior propensity to move. The population-scale social network is a hybrid one, combining observed family ties and locations of the origin with a parameter space calibrated from census, survey and aggregate data and sampled using a stepwise Latin Hypercube Sampling method. At monthly intervals, some agents migrate and these migratory acts change the social network by turning within-nonmigrant connections to between-migrant-nonmigrant connections, turning local connections to nonlocal connections, and adding among-migrant connections. In turn, the changing social network structure updates migratory propensities of those well-connected nonmigrants who become more likely to move. These two processes iterate over time. Using a core-periphery method developed from the k-core decomposition method, we identify and quantify the network structural changes and map these changes with the migration acceleration patterns. We conclude that network structural changes are essential for explaining migration acceleration observed in China during the 1995-2000 period.

  16. The structure of salt marsh soil mesofauna food webs - The prevalence of disturbance.

    Science.gov (United States)

    Haynert, Kristin; Kiggen, Mirijam; Klarner, Bernhard; Maraun, Mark; Scheu, Stefan

    2017-01-01

    Mesofauna taxa fill key trophic positions in soil food webs, even in terrestrial-marine boundary habitats characterized by frequent natural disturbances. Salt marshes represent such boundary habitats, characterized by frequent inundations increasing from the terrestrial upper to the marine pioneer zone. Despite the high abundance of soil mesofauna in salt marshes and their important function by facilitating energy and carbon flows, the structure, trophic ecology and habitat-related diet shifts of mesofauna species in natural salt marsh habitats is virtually unknown. Therefore, we investigated the effects of natural disturbance (inundation frequency) on community structure, food web complexity and resource use of soil mesofauna using stable isotope analysis (15N, 13C) in three salt marsh zones. In this intertidal habitat, the pioneer zone is exposed to inundations twice a day, but lower and upper salt marshes are less frequently inundated based on shore height. The mesofauna comprised 86 species / taxa dominated by Collembola, Oribatida and Mesostigmata. Shifts in environmental disturbances influenced the structure of food webs, diversity and density declined strongly from the land to the sea pointing to the importance of increasing levels of inundation frequency. Accordingly, the reduced diversity and density was associated by a simplification of the food web in the pioneer zone as compared to the less inundated lower and upper salt marsh with a higher number of trophic levels. Strong variations in δ15N signatures demonstrated that mesofauna species are feeding at multiple trophic levels. Primary decomposers were low and most mesofauna species functioned as secondary decomposers or predators including second order predators or scavengers. The results document that major decomposer taxa, such as Collembola and Oribatida, are more diverse than previously assumed and predominantly dwell on autochthonous resources of the respective salt marsh zone. The results further

  17. Chemical modeling of nuclear waste repositories in the salt repository project

    International Nuclear Information System (INIS)

    Jansen, G.; Raines, G.E.; Kircher, J.F.; Hubbard, N.

    1985-01-01

    Salt deposits contain small amounts of water as brine in fluid inclusions in halite and in hydrous minerals, e.g., clays, kieserite (MgSO 4 . H 2 O) and carnallite (KMgCl 3 . 6H 2 O). For the candidate salt deposits, the total amounts of water as volume % brine are: Palo Duro Basin, Texas, approximately 1.8; Paradox Basin, Utah, approximately 5.0 for the carnallite-marker zone, and less than approximately 0.5 below this zone; Gulf Coast salt domes, less than 0.15. For the Palo Duro and Paradox salt, the brines are Mg-rich (approximately 20,000 mg/L to approximately 100,000 mg/L) and sometimes Ca-rich (up to about 20,000 mg/L) NaCl brines. Brine migration calculations have been made using calculations of the time-variant thermal gradient around the waste packages and conservatively high brine volumes in the salt (5.0 volume % for the Texas and Utah sites and 0.5 volume % for the Gulf Coast) as input data. The maximum amounts of brine that eventually migrate to each waste package are about 1.0m 3 (for 5.0 volume % brine) and 0.2m 3 (for 0.5 volume % brine). With current conceptual designs for waste package overpacks (10 to 15 cm thick low-carbon steel), the waste package is not breached by uniform corrosion within 10,000 years. In brines this material thus far shows only uniform corrosion. For the expected conditions, where the brine is provided solely by brine migration, the brine is consumed by reaction with the iron of the overpack nearly as fast as it migrates to the waste package. Therefore, for the expected conditions, data about corrosion rates, radiolysis, etc., are not important. However, it is essential that accurate volumes of in-migrating brine can be calculated

  18. Structural transition in aqueous lipid/bile salt [DPPC/NaDC] supramolecular aggregates: SANS and DLS study

    International Nuclear Information System (INIS)

    Kiselev, M.A.; Janich, M.; Hildebrand, A.; Strunz, P.; Neubert, R.H.H.; Lombardo, D.

    2013-01-01

    Highlights: • Self-assembly in model DPPC lipids and NaDC bile salt by SANS and DLS experiments. • Bile salt creates structural interference against cohesive tendency of DPPC bilayers. • NaDC steric interactions cause transition toward different supramolecular structures. - Abstract: Small angle neutron scattering (SANS) and dynamic light scattering (DLS) were used to study different aggregation states in sodium deoxycholate (NaDC)-phosphatidylcholine systems at T = 60 °C. Size and shape of the aggregates investigated as a function of the NaDC bile salt concentration (at the constant DPPC concentration of 6 mM) indicate a strong dependence of the size and morphology of the generated aggregates on the relative amount of NaDC bile salt. More specifically large occupied area of the bile salt induces a steric interaction which promotes the transition toward a variety of supramolecular structures ranging from ellipsoidal vesicles, ribbon-like structures, up to final spherical mixed micelles at the large amount of bile salt of 10 mM NaDC. The findings of the obtained results give important insight for understanding the formation of different topologies in aqueous lipid–bile salt mixtures as well as stimulate new routes for liposome reconstitution–solubilisation processes suitable for technological applications

  19. Drilling in salt formations; Perfuracao em formacoes salinas

    Energy Technology Data Exchange (ETDEWEB)

    Falcao, Jose Luiz [PETROBRAS, Rio de Janeiro, RJ (Brazil). E e P Engenharia de Producao. Gerencia de Perfuracao e Operacoes Especiais], e-mail: jfalcao@petrobras.com.br; Poiate Junior, Edgard [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas da Petrobras (CENPES). Gerencia de Metodos Cientificos], e-mail: poiate@petrobras.com.br; Costa, Alvaro Maia da [PETROBRAS, Rio de Janeiro, RJ (Brazil). Diretoria de Exploracao e Producao], e-mail: amcta@petrobras.com.br; Alves, Ivan Antonio Silva [PETROBRAS, Rio de Janeiro, RJ (Brazil). E e P Exploracao. Gerencia de Operacoes em Pocos], e-mail: ialves@petrobras.com.br; Eston, Sergio Medici de [Universidade de Sao Paulo (USP), SP (Brazil). Engenharia de Minas e Petroleo], e-mail: e-mail: sergio.eston@poli.usp.br

    2007-12-15

    This paper is a collection of experiences of service companies, operators and PETROBRAS in the drilling of salt rocks in petroleum prospecting. From the exploratory point of view, the presence of these rocks in the area increases the chances of success. By their characteristics, these sediments can deform, dissolve and migrate, creating preferential flow paths and generating stratigraphic structures and traps ideal for the accumulation of hydrocarbons. This has been a well known fact since the beginning of the petroleum industry. In addition to these factors, the salts are almost perfect seals for the accumulations under them. Their presence in sedimentary basins have an important economical significance, not only in the exploratory interpretation phase, but also in the drilling of wells, as they present mechanical characteristics distinct from siliclastic and carbonatic rocks. However, from the operational point of view, the drilling of some of these salt rocks is associated with a large number of well stability problems (in the short term) and the integrity of wellbore liners (in the long term), when compared to other lithologies. (author)

  20. Growth of Ag micro/nanoparticles using stress migration from multilayered metallic structure

    International Nuclear Information System (INIS)

    Lu, Yebo; Li, Yuan; Saka, Masumi

    2015-01-01

    Highlights: • A multilayered metallic structure was proposed to fabricate Ag micro/nanoparticles via stress migration. • Both ductile Pt and brittle TiN films can be used as the passivation layer by providing pathways for atomic migration. • The diameter of the formed Ag particle can be controlled using different material for passivation layer and changing the heating temperature. - Abstract: A multilayered metallic structure, consisting of Cu foil and subsequently deposited Ag thin film covered with a passivation layer, was proposed to fabricate Ag micro/nanoparticles by stress migration. With employing a ductile Pt or brittle TiN thin film as passivation, Ag micro/nanoparticles were successfully fabricated by annealing the corresponding multilayered structure. The relationship between characteristics (average diameter, number and volume) of the formed Ag micro/nanoparticles and the annealing temperature was discussed. On this basis, the growth mechanism was developed, which indicates that the dimension of Ag particles was mainly dominated by the different pathways for the migration of diffused Ag atoms in the passivation layers of Pt and TiN and the annealing temperature

  1. STRUCTURAL ECONOMIC CHANGE AND INTERNATIONAL MIGRATION FROM MEXICO AND POLAND

    Science.gov (United States)

    Massey, Douglas S.; Kalter, Frank; Pren, Karen A.

    2010-01-01

    In this article we use uniquely comparable data sets from two very different settings to examine how exogenous economic transformations affect the likelihood and selectivity of international out-migration. Specifically, we use data from the Mexican Migration Project to construct event history files predicting first U.S. trips from seven communities in the state of Veracruz, which until recently sent very few migrants abroad. Similarly, using data from the Polish Migration Project, we derive comparable event history files predicting first trips to Germany from four Polish communities, which also sent few migrants abroad before the 1980s. Our analyses suggest that the onset of structural adjustment in both places had a significant effect in raising the probability of international migration, even when controlling for a set of standard variables specified by other theories to influence migration propensity, such as the size of the binational income gap and various indicators of human and social capital. PMID:21765550

  2. Salt briquette: the form of salt monopoly in madura, 1883-1911

    Science.gov (United States)

    Wisnu; Alrianingrum, S.; Artono; Liana, C.

    2018-01-01

    This study describes the history of the salt monopoly in Indonesia because it is associated with the issue of salt crisis lately, widely reported in various media. This study tried to find answers to the relationship between monopoly and crisis events through the study of history. Monopoly policy by the government of the colonial period is actually an industrial modernization effort, but it turned out another impact. Although the colonial government wanted to issue a policy that ends strengthens the position of the government in the industry, but ultimately backfire and disasters in the salt industry at the time. This article discusses only the focus of the salt monopoly in Madura as a selection of events, arguing the island as a center of salt in Indonesia. The method used in this study using a review of history. Therefore, their explanations using historical sources. Methodologically through the process of collecting historical sources, criticize these sources, synthesize and interpret the analysis in an array of historical writing. In conclusion, although the salt monopoly policy gives a great advantage to the colonial government, but the overall population of Madura remains in a poor state. It is evident that the Madurese to migrate Madurese to various areas outside the island of Madura, to fix the economy.

  3. Effects of Artificial Ligaments with Different Porous Structures on the Migration of BMSCs

    Directory of Open Access Journals (Sweden)

    Chun-Hui Wang

    2015-01-01

    Full Text Available Polyethylene terephthalate- (PET- based artificial ligaments (PET-ALs are commonly used in anterior cruciate ligament (ACL reconstruction surgery. The effects of different porous structures on the migration of bone marrow mesenchymal stem cells (BMSCs on artificial ligaments and the underlying mechanisms are unclear. In this study, a cell migration model was utilized to observe the migration of BMSCs on PET-ALs with different porous structures. A rabbit extra-articular graft-to-bone healing model was applied to investigate the in vivo effects of four types of PET-ALs, and a mechanical test and histological observation were performed at 4 weeks and 12 weeks. The BMSC migration area of the 5A group was significantly larger than that of the other three groups. The migration of BMSCs in the 5A group was abolished by blocking the RhoA/ROCK signaling pathway with Y27632. The in vivo study demonstrated that implantation of 5A significantly improved osseointegration. Our study explicitly demonstrates that the migration ability of BMSCs can be regulated by varying the porous structures of the artificial ligaments and suggests that this regulation is related to the RhoA/ROCK signaling pathway. Artificial ligaments prepared using a proper knitting method and line density may exhibit improved biocompatibility and clinical performance.

  4. Insular Celtic population structure and genomic footprints of migration.

    Directory of Open Access Journals (Sweden)

    Ross P Byrne

    2018-01-01

    Full Text Available Previous studies of the genetic landscape of Ireland have suggested homogeneity, with population substructure undetectable using single-marker methods. Here we have harnessed the haplotype-based method fineSTRUCTURE in an Irish genome-wide SNP dataset, identifying 23 discrete genetic clusters which segregate with geographical provenance. Cluster diversity is pronounced in the west of Ireland but reduced in the east where older structure has been eroded by historical migrations. Accordingly, when populations from the neighbouring island of Britain are included, a west-east cline of Celtic-British ancestry is revealed along with a particularly striking correlation between haplotypes and geography across both islands. A strong relationship is revealed between subsets of Northern Irish and Scottish populations, where discordant genetic and geographic affinities reflect major migrations in recent centuries. Additionally, Irish genetic proximity of all Scottish samples likely reflects older strata of communication across the narrowest inter-island crossing. Using GLOBETROTTER we detected Irish admixture signals from Britain and Europe and estimated dates for events consistent with the historical migrations of the Norse-Vikings, the Anglo-Normans and the British Plantations. The influence of the former is greater than previously estimated from Y chromosome haplotypes. In all, we paint a new picture of the genetic landscape of Ireland, revealing structure which should be considered in the design of studies examining rare genetic variation and its association with traits.

  5. Application of Post-stack migration to seismic data associated with fault structures

    OpenAIRE

    Koduru Anitha; Mohanty P. R

    2015-01-01

    In hydrocarbon exploration, wave-equation migration techniques play an important role in imaging the complex geological structures. Usually, post-stack migration scheme is applied to the seismic data to improve the resolution with restoration of dipping reflectors to their true position. As a result, the migrated time sections are interpretable in terms of subsurface features. As a numerical study, three fault models are considered for the present study. First of all, ...

  6. Magnetic coupling at perovskite and rock-salt structured interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Matvejeff, M., E-mail: mikko.matvejeff@picosun.com [Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, 277-8581 Chiba (Japan); Department of Chemistry, Aalto University, Kemistintie 1, 02150 Espoo (Finland); Ahvenniemi, E. [Department of Chemistry, Aalto University, Kemistintie 1, 02150 Espoo (Finland); Takahashi, R.; Lippmaa, M. [Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, 277-8581 Chiba (Japan)

    2015-10-05

    We study magnetic coupling between hole-doped manganite layers separated by either a perovskite or a rock-salt barrier of variable thickness. Both the type and the quality of the interface have a strong impact on the minimum critical barrier thickness where the manganite layers become magnetically decoupled. A rock-salt barrier layer only 1 unit cell (0.5 nm) thick remains insulating and is able to magnetically de-couple the electrode layers. The technique can therefore be used for developing high-performance planar oxide electronic devices such as magnetic tunnel junctions and quantum well structures that depend on magnetically and electronically sharp heterointerfaces.

  7. Formation and development of salt crusts on soil surfaces

    KAUST Repository

    Dai, Sheng; Shin, Hosung; Santamarina, Carlos

    2015-01-01

    The salt concentration gradually increases at the soil free surface when the evaporation rate exceeds the diffusive counter transport. Eventually, salt precipitates and crystals form a porous sodium chloride crust with a porosity of 0.43 ± 0.14. After detaching from soils, the salt crust still experiences water condensation and salt deliquescence at the bottom, brine transport across the crust driven by the humidity gradient, and continued air-side precipitation. This transport mechanism allows salt crust migration away from the soil surface at a rate of 5 μm/h forming salt domes above soil surfaces. The surface characteristics of mineral substrates and the evaporation rate affect the morphology and the crystal size of precipitated salt. In particular, substrate hydrophobicity and low evaporation rate suppress salt spreading.

  8. Formation and development of salt crusts on soil surfaces

    KAUST Repository

    Dai, Sheng

    2015-12-14

    The salt concentration gradually increases at the soil free surface when the evaporation rate exceeds the diffusive counter transport. Eventually, salt precipitates and crystals form a porous sodium chloride crust with a porosity of 0.43 ± 0.14. After detaching from soils, the salt crust still experiences water condensation and salt deliquescence at the bottom, brine transport across the crust driven by the humidity gradient, and continued air-side precipitation. This transport mechanism allows salt crust migration away from the soil surface at a rate of 5 μm/h forming salt domes above soil surfaces. The surface characteristics of mineral substrates and the evaporation rate affect the morphology and the crystal size of precipitated salt. In particular, substrate hydrophobicity and low evaporation rate suppress salt spreading.

  9. Petroleum migration pathways and charge concentration: A three-dimensional model

    Energy Technology Data Exchange (ETDEWEB)

    Hindle, A.D. [Anadarko Algeria Corp., Middlesex (United Kingdom)

    1997-09-01

    Petroleum migration pathways through a basin are determined by the three-dimensional distribution of discontinuous sealing surfaces, which are usually parallel to bedding. The petroleum migrates below the sealing surface, taking the structurally most advantageous route. The three-dimensional distribution of migration pathways within the petroleum system can be modeled on a personal computer using a program based on the parameters discussed in this paper. Application of the model to the Paris and Williston basins demonstrates that a good correlation between predicted pathways and discovered accumulations can be made using simple models. Pathways form a dense network overlying generating areas in the central parts of basins. Toward the basin margins these routes commonly become increasingly focused into discrete pathways by the sealing-surface morphologies. Eventually, these pathways may reach the surface as seepages. It is important to integrate surface outcrops of migration routes (surface seepages) into migration modeling. Deflection of the pathways from the structurally most advantageous route below the sealing surface may be caused by lateral sealing barriers due to faces variation in the carrier rock below the seal, fault juxtaposition, or cross-formational seals such as salt intrusions. Deflection of pathways also occurs where there are hydrodynamic conditions in response to topography-driven groundwater flow. Zones of vertical migration are associated with facies changes along the horizon of the sealing surface into a nonsealing facies, or juxtaposition to nonsealing strata by faults. Vertical migration from either normally or abnormally pressured strata is most likely to occur into normally or lesser pressured strata at intrabasinal highs where hydrocarbons can be stored and transferred at times of temporary seal rupture.

  10. The salt stock of the Jura bassin in Ostholstein. A seismologic re-interpretation; Der Salzstock des ostholsteinischen Juratroges. Eine seismische Re-Interpretation

    Energy Technology Data Exchange (ETDEWEB)

    Brink, H.J.; Baykulov, M.; Gajewski, D.; Yoon, Mi-Kyung [Hamburg Univ. (Germany). Inst. fuer Geophysik

    2008-10-23

    The developing age of the Permian salt stocks in Schleswig-Holstein (Federal Republic of Germany) reaches from the Trias over the Jura up to the Tertiary period. In the context of the DGMK project 577-1, the reflection-rich salt dome in the East Holstein Jura was investigated seismically by means of the CRS method and speed tomography. These measurements enable the interpretation of a structural style with a substantial tectonically compressive component. Magnetotelluric measurements point to potential natural gas source rocks. The drift of the Permian salt contributes to the contact support of new red sandstone on the pre-salinar layers. Migration ways are opened which contributed to a filling of structurally high new red sandstone reservoirs in small depths.

  11. Novel ordered structures in the mixture of water/organic solvent/salts investigated by neutron scattering

    International Nuclear Information System (INIS)

    Sadakane, Koichiro

    2013-01-01

    The effect of an antagonistic salt on the phase behavior and nanoscale structure of a mixture of water/organic solvent was investigated by visual inspection, optical microscope, and small-angle neutron scattering (SANS). The addition of the antagonistic salt, namely sodium tetraphenylborate (NaBPh 4 ), induces the shrinking of the two-phase region in contrast to the case in which a normal (hydrophilic) salt is added. Below the phase separation point, the SANS profiles cannot be described by the Ornstein-Zernike function owing to the existence of a long-range periodic structure. With increasing salt concentration, the critical exponents change from the values of 3D-Ising and approach those of 2D-Ising. Furthermore, an ordered phase with multilamellar (onion) structures was confirmed in an off-critical mixture of D 2 O and 3-methylpyridine containing 85 mM of a NaBPh 4 although no surfactants or polymers are contained. (author)

  12. Two Voriconazole salts: Syntheses, crystal structures, solubility and bioactivities

    Science.gov (United States)

    Tang, Gui-Mei; Wang, Yong-Tao

    2018-01-01

    Two Voriconazole salts, namely, (H2FZ)2+·2(Cl-) (1) and (HFZ)+·NO3- (2) (FZ = (2R,3S)-2-(2,4-difluorophenyl)-3-(5-fluoro-4-pyrimidiny)-1-(1H-1,2,4-triazol-1-yl)-2-butanol) have been obtained through the reaction of Voriconazole, hydrochloric acid and nitrate acid, respectively. They were structurally characterized by FT-IR, elemental analyses (EA), single crystal X-ray diffraction, and thermogravimetric analysis (TGA). A variety of hydrogen bonds (Osbnd H⋯N, Nsbnd H⋯Cl/O, Csbnd H⋯N/OF/Cl) were observed in the compounds 1 and 2, through which a 3D supramolecular architecture is generated. Both two salts 1 and 2 show the promising bioactivities against Aspergillus species (Aspergillus niger, Aspergillus terreus, Aspergillus fumigatus and Aspergillus flavus) and Candida ones (Candida albicans, Candida krusei, Candida glabrata and Cryptococcus neoformans), which is obviously more excellent than that of FZ. Additionally, the solubility of two salts is considerably higher than that of the drug Voriconazole.

  13. Balancing sub- and supra-salt strain in salt-influenced rifts: Implications for extension estimates

    Science.gov (United States)

    Coleman, Alexander J.; Jackson, Christopher A.-L.; Duffy, Oliver B.

    2017-09-01

    The structural style of salt-influenced rifts may differ from those formed in predominantly brittle crust. Salt can decouple sub- and supra-salt strain, causing sub-salt faults to be geometrically decoupled from, but kinematically coupled to and responsible for, supra-salt forced folding. Salt-influenced rifts thus contain more folds than their brittle counterparts, an observation often ignored in extension estimates. Fundamental to determining whether sub- and supra-salt structures are kinematically coherent, and the relative contributions of thin- (i.e. gravity-driven) and thick-skinned (i.e. whole-plate stretching) deformation to accommodating rift-related strain, is our ability to measure extension at both structural levels. We here use published physical models of salt-influenced extension to show that line-length estimates yield more accurate values of sub- and supra-salt extension compared to fault-heave, before applying these methods to seismic data from the Halten Terrace, offshore Norway. We show that, given the abundance of ductile deformation in salt-influenced rifts, significant amounts of extension may be ignored, leading to the erroneous interpretations of thin-skinned, gravity-gliding. If a system is kinematically coherent, supra-salt structures can help predict the occurrence and kinematics of sub-salt faults that may be poorly imaged and otherwise poorly constrained.

  14. Salt marsh-mangrove ecotones: using structural gradients to investigate the effects of woody plant encroachment on plant-soil interactions and ecosystem carbon pools

    Science.gov (United States)

    Yando, Erik S.; Osland, Michael J.; Willis, Jonathan M; Day, Richard H.; Krauss, Ken W.; Hester, Mark W.

    2016-01-01

    Changing winter climate extremes are expected to result in the poleward migration of mangrove forests at the expense of salt marshes. Although mangroves and marshes are both highly valued ecosystems, the ecological implications of mangrove expansion have not been fully investigated.

  15. The connection between migration and regional structure in Finland around 1990 - a GIS viewpoint

    Directory of Open Access Journals (Sweden)

    Jarkko Kauppinen

    2000-01-01

    Full Text Available The connection between migration and regional structure in Finland in the early 19905 is discussed on the basis of Geographic Irformation Systems (GIS data from Statistics Finland, compiled for map coordinate grid cells of 1 x 1 km. The results indicate that data of this kind enable a more detailed typology to be drawn up for migration. At the regional level, this allows the defining of places of "passing through '' which gain population from other local government districts but lose population through migration within their own district. The connection between migration and regional structure is manifested in the fact that flows both between and within local government districts mainly involve the more urbanised population centres and areas with: high levels of unemployment.

  16. Temporal genetic population structure and interannual variation in migration behavior of Pacific Lamprey Entosphenus tridentatus

    Science.gov (United States)

    Clemens, Benjamin J.; Wyss, Lance A.; McCoun, Rebecca; Courter, Ian; Schwabe, Lawrence; Peery, Christopher; Schreck, Carl B.; Spice, Erin K.; Docker, Margaret F.

    2017-01-01

    Studies using neutral loci suggest that Pacific lamprey, Entosphenus tridentatus, lack strong spatial genetic population structure. However, it is unknown whether temporal genetic population structure exists. We tested whether adult Pacific lamprey: (1) show temporal genetic population structure; and (2) migrate different distances between years. We non-lethally sampled lamprey for DNA in 2009 and 2010 and used eight microsatellite loci to test for genetic population structure. We used telemetry to record the migration behaviors of these fish. Lamprey were assignable to three moderately differentiated genetic clusters (FST = 0.16–0.24 for all pairwise comparisons): one cluster was composed of individuals from 2009, and the other two contained individuals from 2010. The FST value between years was 0.13 and between genetic clusters within 2010 was 0.20. A total of 372 (72.5%) fish were detected multiple times during their migrations. Most fish (69.9%) remained in the mainstem Willamette River; the remaining 30.1% migrated into tributaries. Eighty-two lamprey exhibited multiple back-and-forth movements among tributaries and the mainstem, which may indicate searching behaviors. All migration distances were significantly greater in 2010, when the amplitude of river discharge was greater. Our data suggest genetic structuring between and within years that may reflect different cohorts.

  17. Brine flow in heated geologic salt.

    Energy Technology Data Exchange (ETDEWEB)

    Kuhlman, Kristopher L.; Malama, Bwalya

    2013-03-01

    This report is a summary of the physical processes, primary governing equations, solution approaches, and historic testing related to brine migration in geologic salt. Although most information presented in this report is not new, we synthesize a large amount of material scattered across dozens of laboratory reports, journal papers, conference proceedings, and textbooks. We present a mathematical description of the governing brine flow mechanisms in geologic salt. We outline the general coupled thermal, multi-phase hydrologic, and mechanical processes. We derive these processes governing equations, which can be used to predict brine flow. These equations are valid under a wide variety of conditions applicable to radioactive waste disposal in rooms and boreholes excavated into geologic salt.

  18. Effect of basement structure and salt tectonics on deformation styles along strike: An example from the Kuqa fold-thrust belt, West China

    Science.gov (United States)

    Neng, Yuan; Xie, Huiwen; Yin, Hongwei; Li, Yong; Wang, Wei

    2018-04-01

    The Kuqa fold-thrust belt (KFTB) has a complex thrust-system geometry and comprises basement-involved thrusts, décollement thrusts, triangle zones, strike-slip faults, transpressional faults, and pop-up structures. These structures, combined with the effects of Paleogene salt tectonics and Paleozoic basement uplift form a complex structural zone trending E-W. Interpretation and comprehensive analysis of recent high-quality seismic data, field observations, boreholes, and gravity data covering the KFTB has been performed to understand the characteristics and mechanisms of the deformation styles along strike. Regional sections, fold-thrust system maps of the surface and the sub-salt layer, salt and basement structure distribution maps have been created, and a comprehensive analysis of thrust systems performed. The results indicate that the thrust-fold system in Paleogene salt range can be divided into five segments from east to west: the Kela-3, Keshen, Dabei, Bozi, and Awate segments. In the easternmost and westernmost parts of the Paleogene salt range, strike-slip faulting and basement-involved thrusting are the dominant deformation styles, as basement uplift and the limits of the Cenozoic evaporite deposit are the main controls on deformation. Salt-core detachment fold-thrust systems coincide with areas of salt tectonics, and pop-up, imbricate, and duplex structures are associated with the main thrust faults in the sub-salt layer. Distribution maps of thrust systems, basement structures, and salt tectonics show that Paleozoic basement uplift controlled the Paleozoic foreland basin morphology and the distribution of Cenozoic salt in the KFTB, and thus had a strong influence on the segmented structural deformation and evolution of the fold-thrust belt. Three types of transfer zone are identified, based on the characteristics of the salt layer and basement uplift, and the effects of these zones on the fault systems are evaluated. Basement uplift and the boundary of

  19. Structure and agency in development-induced forced migration: the case of Brazil's Belo Monte Dam.

    Science.gov (United States)

    Randell, Heather

    2016-03-01

    This paper examines how structure and agency interact to shape forced migration outcomes. Specifically, I ask how structural factors such as compensation policies as well as social, financial, and human capital may either foster or constrain migration aspirations and capabilities. I use longitudinal, semi-structured interview data to study forced migration among farmers displaced by the Belo Monte Dam in the Brazilian Amazon. Results from baseline interviews indicate that nearly all community members aspired to purchase rural land in the region and maintain livelihoods as cacao farmers or cattle ranchers. Constraints limiting the ability to attain aspirations included strict requirements on land titles for properties, delays in receiving compensation, rising land prices, and the lack of power to negotiate for better compensation. Despite these constraints, most migrants succeeded in attaining aspirations, as they were able to mobilize resources such as social networks, financial capital, skills, and knowledge. These findings highlight the importance of considering the relationship between structure and agency within forced migration research. I conclude by discussing how the findings may inform resettlement policies for future cases of development- or environment-induced forced migration.

  20. Geologic appraisal of Paradox basin salt deposits for water emplacement

    Science.gov (United States)

    Hite, Robert J.; Lohman, Stanley William

    1973-01-01

    Thick salt deposits of Middle Pennsylvanian age are present in an area of 12,000 square miles in the Paradox basin of southeast Utah and southwest Colorado. The deposits are in the Paradox Member of the Hermosa Formation. The greatest thickness of this evaporite sequence is in a troughlike depression adjacent to the Uncompahgre uplift on the northeast side of the basin.The salt deposits consist of a cyclical sequence of thick halite units separated by thin units of black shale, dolomite, and anhydrite. Many halite units are several hundred feet thick and locally contain economically valuable potash deposits.Over much of the Paradox basin the salt deposits occur at depths of more than 5,000 feet. Only in a series of salt anticlines located along the northeastern side of the basin do the salt deposits rise to relatively shallow depths. The salt anticlines can be divided geographically and structurally into five major systems. Each system consists of a long undulating welt of thickened salt over which younger rocks are arched in anticlinal form. Locally there are areas along the axes of the anticlines where the Paradox Member was never covered by younger sediments. This allowed large-scale migration of Paradox strata toward and up through these holes in the sediment cover forming diapiric anticlines.The central or salt-bearing cores of the anticlines range in thickness from about 2,500 to 14,000 feet. Structure in the central core of the salt anticlines is the result of both regional-compression and flowage of the Paradox Member into the anticlines from adjacent synclines. Structure in the central cores of the salt anticlines ranges from relatively undeformed beds to complexly folded and faulted masses, in which stratigraphic continuity is undemonstrable.The presence of thick cap rock .over many of the salt anticlines is evidence of removal of large volumes of halite by groundwater. Available geologic and hydrologic information suggests that this is a relatively slow

  1. The Spatial Structure of Planform Migration - Curvature Relation of Meandering Rivers

    Science.gov (United States)

    Guneralp, I.; Rhoads, B. L.

    2005-12-01

    Planform dynamics of meandering rivers have been of fundamental interest to fluvial geomorphologists and engineers because of the intriguing complexity of these dynamics, the role of planform change in floodplain development and landscape evolution, and the economic and social consequences of bank erosion and channel migration. Improved understanding of the complex spatial structure of planform change and capacity to predict these changes are important for effective stream management, engineering and restoration. The planform characteristics of a meandering river channel are integral to its planform dynamics. Active meandering rivers continually change their positions and shapes as a consequence of hydraulic forces exerted on the channel banks and bed, but as the banks and bed change through sediment transport, so do the hydraulic forces. Thus far, this complex feedback between form and process is incompletely understood, despite the fact that the characteristics and the dynamics of meandering rivers have been studied extensively. Current theoretical models aimed at predicting planform dynamics relate rates of meander migration to local and upstream planform curvature where weighting of the influence of curvature on migration rate decays exponentially over distance. This theoretical relation, however, has not been rigorously evaluated empirically. Furthermore, although models based on exponential-weighting of curvature effects yield fairly realistic predictions of meander migration, such models are incapable of reproducing complex forms of bend development, such as double heading or compound looping. This study presents the development of a new methodology based on parametric cubic spline interpolation for the characterization of channel planform and the planform curvature of meandering rivers. The use of continuous mathematical functions overcomes the reliance on bend-averaged values or piece-wise discrete approximations of planform curvature - a major limitation

  2. Relationship between mechanical properties and crystal structure in cocrystals and salt of paracetamol.

    Science.gov (United States)

    Ahmed, Hamzah; Shimpi, Manishkumar R; Velaga, Sitaram P

    2017-01-01

    Objectives were to study mechanical properties of various solid forms of paracetamol and relate to their crystal structures. Paracetamol form I (PRA), its cocrystals with oxalic acid (PRA-OXA) and 4,4-bipyridine (PRA-BPY) and hydrochloride salt (PRA-HCL) were selected. Cocrystals and salt were scaled-up using rational crystallization methods. The resulting materials were subjected to different solid-state characterizations. The powders were sieved and 90-360 µm sieve fraction was considered. These powders were examined by scanning electron microscopy (SEM) and densities were determined. Tablets were made at applied pressures of 35-180 MPa under controlled conditions and the tablet height, diameter and hardness were measured. Tensile strength and porosity of the tablets were estimated using well known models. Crystal structures of these systems were visualized and slip planes were identified. Cocrystal and salt of PRA were physically pure. Sieved powders had comparable morphologies and particle size. The apparent and theoretical densities of powders were similar, but no clear trends were observed. The tensile strengths of these compacts were increased with increasing pressure whereas tabletability decreased in the order oxalic acid > PRA-HCL ≈ PRA-OXA > BPY > PRA-BPY. Tablet tensile strength decreases exponentially with increasing porosity with the exception of PRY-BPY and BPY. Slip plane prediction based on attachment energies may not be independently considered. However, it was possible to explain the improved mechanical properties of powders based on the crystal structure. Cocrystallization and salt formation have introduced structural features that are responsible for improved tableting properties of PRA.

  3. Suppression of acyl migration in enzymatic production of structured lipids through temperature programming

    DEFF Research Database (Denmark)

    Yang, Tiankui; Fruekilde, Maj-Britt; Xu, Xuebing

    2005-01-01

    Acyl migration in the glycerol backbone often leads to the increase of by-products in the enzymatic production of specific structured lipids. Acyl migration is a thermodynamic process and is very difficult to stop fully in actual reactions. The objective of this study was to investigate...

  4. Structure, Ion Transport, and Rheology of Nanoparticle Salts

    KAUST Repository

    Wen, Yu Ho

    2014-07-08

    Above a critical surface chemistry-dependent particle loading associated with nanoscale interparticle spacing, ligand-ligand interactions-both electrostatic and steric-come into play and govern the structure and dynamics of charged oligomer-functionalized nanoparticle suspensions. We report in particular on the structure, ion transport, and rheology of suspensions of nanoparticle salts created by cofunctionalization of silica particles with tethered sulfonate salts and oligomers. Dispersion of the hairy ionic particles into medium and high dielectric constant liquids yields electrolytes with unique structure and transport properties. We find that electrostatic repulsion imparted by ion dissociation can be tuned to control the dispersion state and rheology through counterion size (i.e., Li+, Na+, and K+) and dielectric properties of the dispersing medium. Analysis of small-angle X-ray scattering (SAXS) structure factors and the mechanical modulus shows that when the interparticle spacing approaches nanometer dimensions, weakly entangled anchored ligands experience strong and long-lived topological constraints analogous to those normally found in well-entangled polymeric fluids. This finding provides insight into the molecular origins of the surprisingly similar rubbery plateau moduli observed in hairy nanoparticle suspensions and entangled polymers of the same chemistry as the tethered ligands. Additionally, we find that a time-composition superposition (TCS) principle exists for the suspensions, which can be used to substantially extend the observation time over which dynamics are observed in jammed, soft glassy suspensions. Application of TCS reveals dynamical similarities between the suspensions and entangled solutions of linear polymer chains; i.e., a hairy particle trapped in a cage appears to exhibit analogous dynamics to a long polymer chain confined to a tube. © 2014 American Chemical Society.

  5. Structural, micro-structural and kinematic analyses of channel flow in the Karmostaj salt diapir in the Zagros foreland folded belt, Fars province, Iran

    Science.gov (United States)

    Sarkarinejad, Khalil; Sarshar, Maryam Asadi; Adineh, Sadegh

    2018-02-01

    One of the main characteristic of the Zagros foreland fold-and-thrust belt and the Zagros foreland folded belt are wide distributions of surface extrusion from the Hormuz salt diapirs. This study examines the structure and kinematic of channel flow in the Karmostaj salt diapir in the southwestern part of the Zagros foreland folded belt. This diapir has reached the surface as a result of the channel flow mechanism and has extruded in the southern limb of the Kuh-Gach anticline which is an asymmetric décollement fold with convergence to the south. Structural and microstructural studies and quantitative finite strain (Rs) and kinematic vorticity number (Wk) analyses were carried out within this salt diapir and its namakier. This was in order to investigate the structural evolution in the salt diapiric system, the characteristics and mechanism of the salt flow and the distribution of flow regimes within the salt diapir and interaction of regional tectonics and salt diaprism. The extruded salt has developed a flow foliation sub-parallel to the remnant bedding recorded by different colors, a variety of internal folds including symmetrical and asymmetrical folds and interference fold patterns, shear zones, and boudins. These structures were used to analyze mechanisms and history of diapiric flow and extrusion. The microstructures, reveal various deformation mechanisms in various parts of salt diapir. The measurements of finite strain show that Rs values in the margin of salt diapir are higher than within its namakier which is consistent with the results of structural studies. Mean kinematic vorticity number (Wm) measured in steady state deformation of diapir and namakier is Wm = 0.45-0.48 ± 0.13. The estimated mean finite deformation (Wm) values indicate that 67.8% pure shear and 32.2% simple shear deformation were involved; the implications of which are discussed. The vorticity of flow indicates that in the early stage of growth, Poiseuille flow was the dominate

  6. Evaluation of the Influence of Salt Treatment on the Structure of ...

    African Journals Online (AJOL)

    Evaluation of the Influence of Salt Treatment on the Structure of Pyrolyzed ... Studies to characterize the activated carbon were conducted at ambient conditions. ... as iodine number and porosity; and minimum values for parameters like pH and ...

  7. Structural and thermal development of the Atlantic margin offshore Essaouira (Morocco) - evidence of salt extrusion and implications for hydrocarbon exploration

    Science.gov (United States)

    Neumaier, Martin; Littke, Raf; Kleine, Adrian; Schnabel, Michael; Reichert, Christian

    2013-04-01

    Along the east-west regional seismic line BGR11-202 (MIRROR campaign, 2011), several distinct salt diapirs and related structures can be identified close to the present day coast line. The subsalt structure is only very poorly imaged. Further offshore, rotated fault blocks are overlain by Mesozoic and Cenozoic sediments. Towards the west, the evidence for past volcanic activity is increasing (necks, dykes, and sills). The magnetic anomaly S1 is roughly situated west of the most western identifiable salt structure. The aim of our study is to describe and verify possible salt tectonic and related thermal models and the evolution of the petroleum systems. One salt structure in particular shows clear evidence of salt extrusion in the past. We explain the potential scenario of the salt diapir development and extrusion in a series of structurally restored sections: After deposition, probably within the syn-rift Liassic half grabens (not imaged), the salt quickly became instable due to differential loading, assisted by growing density contrast with the overburden. It forced its way up using weak zones—which could have been the active normal faults—while the overburden collapsed into the previously occupied space (salt withdrawal). Even though the salt was constantly rising, it did not reach the surface due to constant burial. Only once the sedimentation rate decreased—during the late Cretaceous and early Paleogene—the salt extruded and crept down the continental slope onto the hiatus unconformity. With the extrusion, the salt partly dissolved in contact with the ocean water, and a cap rock formed. The related paleorelief was buried by the detritical sediments provided by the Atlas orogenesis. At present day, these paleoreliefs still have a bathymetric expression, as they are providing an unstable underground and trigger normal faulting and local resedimentation. Also remobilization of the salt, even though strengthened by the cap rock, might be possible locally

  8. De-icing salt contamination reduces urban tree performance in structural soil cells.

    Science.gov (United States)

    Ordóñez-Barona, Camilo; Sabetski, Vadim; Millward, Andrew A; Steenberg, James

    2018-03-01

    Salts used for de-icing roads and sidewalks in northern climates can have a significant impact on water quality and vegetation. Sub-surface engineering systems, such as structural soil cells, can regulate water runoff and pollutants, and provide the necessary soil volume and irrigation to grow trees. However, the ability of such systems to manage de-icing salt contamination, and the impact of this contamination on the trees growing in them, have not been evaluated. We report on an field investigation of de-icing salt contamination in structural cells in two street-revitalization projects in Toronto, Canada, and the impact of this contamination on tree performance. We analyzed soil chemistry and collected tree attributes; these data were examined together to understand the effect of salinity on tree mortality rates and foliar condition. Data collected from continuous soil salinity loggers from April to June for one of the two sites were used to determine whether there was a long-term accumulation of salts in the soils. Results for both sites indicate that both sites displayed high salinity and alkalinity, with levels elevated beyond those suggested before those reported to cause negative tree effects. For one site, trees that were alive and trees that had a better foliar condition had significantly lower levels of soil salinity and alkalinity than other trees. High salinity and alkalinity in the soil were also associated with lower nutrient levels for both sites. Although tests for salinity accumulation in the soils of one site were negative, a longer monitoring of the soil conditions within the soil cells is warranted. Despite structural cells being increasingly utilized for their dual role in storm-water management and tree establishment, there may be a considerable trade-off between storm-water management and urban-forest function in northern climates where de-icing salt application continues to be commonplace. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Crystal structures of seven molecular salts derived from benzylamine and organic acidic components

    Science.gov (United States)

    Wen, Xianhong; Jin, Xiunan; Lv, Chengcai; Jin, Shouwen; Zheng, Xiuqing; Liu, Bin; Wang, Daqi; Guo, Ming; Xu, Weiqiang

    2017-07-01

    Cocrystallization of the commonly available organic amine, benzylamine, with a series of organic acids gave a total of seven molecular salts with the compositions: (benzylamine): (p-toluenesulfonic acid) (1) [(HL)+ · (tsa-)], (benzylamine): (o-nitrobenzoic acid) (2) [(HL+) · (onba)-], (benzylamine): (3,4-methylenedioxybenzoic acid) (3) [(HL+) · (mdba-)], (benzylamine): (mandelic acid) (4) [(HL+) · (mda-)], (benzylamine): (5-bromosalicylic acid)2(5) [(HL+) · (bsac-) · (Hbsac)], (benzylamine): (m-phthalic acid) (6) [(HL+) · (Hmpta-)], and (benzylamine)2: (trimesic acid) (7) [(HL+)2 · (Htma2-)]. The seven salts have been characterised by X-ray diffraction technique, IR, and elemental analysis, and the melting points of all the salts were also reported. And their structural and supramolecular aspects are fully analyzed. The result reveals that among the seven investigated crystals the NH2 groups in the benzylamine moieties are protonated when the organic acids are deprotonated, and the crystal packing is interpreted in terms of the strong charge-assisted Nsbnd H⋯O hydrogen bond formation between the ammonium and the deprotonated acidic groups. Except the Nsbnd H⋯O hydrogen bond, the Osbnd H⋯O hydrogen bonds (charge assisted or neutral) were also found at the salts 4-7. Further analysis of the crystal packing of the salts indicated that a different family of additional CHsbnd O/CH2sbnd O, CHsbnd π/CH2sbnd π, Osbnd O, and Osbnd Cπ associations contribute to the stabilization and expansion of the total high-dimensional (2D-3D) framework structures. For the coexistence of the various weak nonbonding interactions these structures adopted homo or hetero supramolecular synthons or both. Some classical supramolecular synthons, such as R42(8), R43(10) and R44(12), usually observed in organic solids of organic acids with amine, were again shown to be involved in constructing most of these hydrogen bonding networks.

  10. Migration and the Transformation of Multiethnic Population Structure in the Kaliningrad Region of the Post-Soviet Era

    Directory of Open Access Journals (Sweden)

    Zimovina E. P.

    2014-06-01

    Full Text Available This paper analyses the migration processes and their influence on the transformation of multiethnic population structure in the Kaliningrad region. The author uses official statistics (current statistics and census data, as well as interviews with the representatives of ethnic cultural associations as information sources. Special attention is paid to the migration features associated with different ethnic groups. The author identifies major reasons behind the incoming and outgoing movement of population. In the post-Soviet period the Kaliningrad region has experienced positive net migration. This active migration into the region has contributed to the development of “migration networks” and established a new basis for further population increase through migration. The article describes changes in the regional multiethnic population structure and identifies key factors behind them. It is concluded that migration has played the decisive role in the process of multiethnic population structure transformation in the Kaliningrad region in the post-Soviet period. The author views migration as a serious test for both the migrants and the receiving society. On the one hand, migrants have to adapt to a different national, cultural, and linguistic environment and look for the ways of successful integration into the receiving society. On the other hand, the receiving society also faces a serious transformation as a result of the changing population size and structure, the emergence of new elements in culture, rules of behaviour, and the development of new attitudes.

  11. Role of thermodynamic, kinetic and structural factors in the recrystallization behavior of amorphous erythromycin salts

    Energy Technology Data Exchange (ETDEWEB)

    Nanakwani, Kapil; Modi, Sameer R.; Kumar, Lokesh; Bansal, Arvind K., E-mail: akbansal@niper.ac.in

    2014-04-01

    Graphical abstract: - Highlights: • Crystallization kinetics of amorphous erythromycin salts was assessed. • Contribution of thermodynamic, kinetic and structural factors was evaluated. • Role of counterions on physical stability of amorphous salts was investigated. • Implications of the study: In rationalizing stabilization approach for amorphous form. - Abstract: Amorphous form has become an important drug delivery strategy for poorly water soluble drugs. However, amorphous form has inherent physical instability due to its tendency to recrystallize to stable crystalline form. In the present study, amorphous forms of erythromycin free base (ED) and its salts namely, stearate (ES), phosphate (EP) and thiocyanate (ET) were generated by in situ melt quenching and evaluated for their crystallization tendency. Salts were characterized for kinetic, thermodynamic and structural factors to understand crystallization behavior. Kinetics of crystallization followed the order as ES > EP > ET > ED. Fragility and molecular mobility does not completely explain these findings. However, configurational entropy (S{sub conf}), indicative of entropic barrier to crystallization, followed the order as ET > EP > ES > ED. Lower crystallization tendency of ED can be explained by its lower thermodynamic driving force for crystallization (H{sub conf}). This correlated well with different structural parameters for the counter ions.

  12. Structure and agency in development-induced forced migration: the case of Brazil’s Belo Monte Dam

    Science.gov (United States)

    2017-01-01

    This paper examines how structure and agency interact to shape forced migration outcomes. Specifically, I ask how structural factors such as compensation policies as well as social, financial, and human capital may either foster or constrain migration aspirations and capabilities. I use longitudinal, semi-structured interview data to study forced migration among farmers displaced by the Belo Monte Dam in the Brazilian Amazon. Results from baseline interviews indicate that nearly all community members aspired to purchase rural land in the region and maintain livelihoods as cacao farmers or cattle ranchers. Constraints limiting the ability to attain aspirations included strict requirements on land titles for properties, delays in receiving compensation, rising land prices, and the lack of power to negotiate for better compensation. Despite these constraints, most migrants succeeded in attaining aspirations, as they were able to mobilize resources such as social networks, financial capital, skills, and knowledge. These findings highlight the importance of considering the relationship between structure and agency within forced migration research. I conclude by discussing how the findings may inform resettlement policies for future cases of development- or environment-induced forced migration. PMID:28298745

  13. Program management plan for the Molten Salt Reactor Experiment Remediation Project at Oak Ridge National Laboratory, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    1996-09-01

    The primary mission of the Molten Salt Reactor Experiment (MSRE) Remediation Project is to effectively implement the risk-reduction strategies and technical plans to stabilize and prevent further migration of uranium within the MSRE facility, remove the uranium and fuel salts from the system, and dispose of the fuel and flush salts by storage in appropriate depositories to bring the facility to a surveillance and maintenance condition before decontamination and decommissioning. This Project Management Plan (PMP) for the MSRE Remediation Project details project purpose; technical objectives, milestones, and cost objectives; work plan; work breakdown structure (WBS); schedule; management organization and responsibilities; project management performance measurement planning, and control; conduct of operations; configuration management; environmental, safety, and health compliance; quality assurance; operational readiness reviews; and training

  14. Program management plan for the Molten Salt Reactor Experiment Remediation Project at Oak Ridge National Laboratory, Oak Ridge, Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-09-01

    The primary mission of the Molten Salt Reactor Experiment (MSRE) Remediation Project is to effectively implement the risk-reduction strategies and technical plans to stabilize and prevent further migration of uranium within the MSRE facility, remove the uranium and fuel salts from the system, and dispose of the fuel and flush salts by storage in appropriate depositories to bring the facility to a surveillance and maintenance condition before decontamination and decommissioning. This Project Management Plan (PMP) for the MSRE Remediation Project details project purpose; technical objectives, milestones, and cost objectives; work plan; work breakdown structure (WBS); schedule; management organization and responsibilities; project management performance measurement planning, and control; conduct of operations; configuration management; environmental, safety, and health compliance; quality assurance; operational readiness reviews; and training.

  15. Depth migration and de-migration for 3-D migration velocity analysis; Migration profondeur et demigration pour l'analyse de vitesse de migration 3D

    Energy Technology Data Exchange (ETDEWEB)

    Assouline, F.

    2001-07-01

    3-D seismic imaging of complex geologic structures requires the use of pre-stack imaging techniques, the post-stack ones being unsuitable in that case. Indeed, pre-stack depth migration is a technique which allows to image accurately complex structures provided that we have at our disposal a subsurface velocity model accurate enough. The determination of this velocity model is thus a key element for seismic imaging, and to this end, migration velocity analysis methods have met considerable interest. The SMART method is a specific migration velocity analysis method: the singularity of this method is that it does not rely on any restrictive assumptions on the complexity of the velocity model to determine. The SMART method uses a detour through the pre-stack depth migrated domain for extracting multi-offset kinematic information hardly accessible in the time domain. Once achieved the interpretation of the pre-stack depth migrated seismic data, a kinematic de-migration technique of the interpreted events enables to obtain a consistent kinematic database (i.e. reflection travel-times). Then, the inversion of these travel-times, by means of reflection tomography, allows the determination of an accurate velocity model. To be able to really image geologic structures for which the 3-D feature is predominant, we have studied the implementation of migration velocity analysis in 3-D in the context of the SMART method, and more generally, we have developed techniques allowing to overcome the intrinsic difficulties in the 3-D aspects of seismic imaging. Indeed, although formally the SMART method can be directly applied to the case of 3-D complex structures, the feasibility of its implementation requires to choose well the imaging domain. Once this choice done, it is also necessary to conceive a method allowing, via the associated de-migration, to obtain the reflection travel-times. We first consider the offset domain which constitutes, still today, the strategy most usually used

  16. Rock salt as a medium for long-term isolation of radioactive wastes - a reassessment

    International Nuclear Information System (INIS)

    Chaturvedi, L.

    1985-01-01

    Rock salt has been regarded as a suitable medium for the permanent disposal of high and medium level radioactive wastes since the National Academy of Sciences recommended it in 1957. As a result of detained site-specific studies conducted for the Waste Isolation Pilot Plant (WIPP) project in New Mexico, however, several potential problems which are unique to bedded salt deposits have emerged. These include 1) the need to delineate the extent and rate of past dissolution and projections for the future, 2) the origin and significance of brines often found underlying the salt beds, 3) the rate and volume of migration of brine from the salt crystals towards the heat producing waste canisters, 4) the creep rates and implications for retrievability, and 5) the existence of potash and oil and gas resources with implications of human intrusion in the future. These questions will also be faced for sites in salt domes with added complications due to more complex structure and hydrology. The experience at WIPP shows that the site characterization process for high level waste repositories in bedded or dome salt should aim at identifying the important issues of site suitability early in the process and a clear program should be established to address these issues

  17. An Investigation into the Effects of Temperature Gradient on the Soil Water–Salt Transfer with Evaporation

    Directory of Open Access Journals (Sweden)

    Rong Ren

    2017-06-01

    Full Text Available Temperature gradients exist in the field under brackish water irrigation conditions, especially in northern semi–arid areas of China. Although there are many investigators dedicated to studying the mechanism of brackish water irrigation and the effect of brackish water irrigation on crops, there are fewer investigations of the effects of temperature gradient on the water–salt transport. Based on the combination of a physical experiment and a mathematical model, this study was conducted to: (a build a physical model and observe the redistribution of soil water–heat–salt transfer; (b develop a mathematical model focused on the influence of a temperature gradient on soil water and salt redistribution based on the physical model and validate the proposed model using the measured data; and (c analyze the effects of the temperature gradient on the soil water–salt transport by comparing the proposed model with the traditional water–salt model in which the effects of temperature gradient on the soil water–salt transfer are neglected. Results show that the soil temperature gradient has a definite influence on the soil water–salt migration. Moreover, the effect of temperature gradient on salt migration was greater than that of water movement.

  18. Human deoxyhaemoglobin-2,3-diphosphoglycerate complex low-salt structure at 2.5 A resolution.

    Science.gov (United States)

    Richard, V; Dodson, G G; Mauguen, Y

    1993-09-20

    The haemoglobin-2,3-diphosphoglycerate complex structure has been solved at 2.5 A resolution using crystals grown from low-salt solutions. The results show some important differences with the precedent haemoglobin-2,3-diphosphoglycerate high-salt structure solved by Arnone. First, we observe a loss of symmetry in the binding site, secondly both of the lysine residues 82 beta interact with 2,3-diphosphoglycerate at the same time, each making two contacts. This level of interaction is in agreement with the functional behaviour of natural haemoglobin mutants with mutations at the 2,3-diphosphoglycerate binding site.

  19. Morphology and anatomical structure of the larval salt gland of ...

    African Journals Online (AJOL)

    The general structure of the salt gland of nauplii cultured at 180 g/L disappeared. Semiquantitative APH-1 mRNA analysis indicated that the gene was expressed in all tested salinities. The expression did not change remarkably between 25 and 40 g/L salinities. As salinity increased, the gene was up regulated at 70 g/L and ...

  20. Salt supply to and significance of asymmetric salt diapirs

    DEFF Research Database (Denmark)

    Koyi, H.; Burliga, S.; Chemia, Zurab

    2012-01-01

    Salt diapirs can be asymmetric both internally and externally reflecting their evolution history. As such, this asymmetry bear a significant amount of information about the differential loading (± lateral forces) and in turn the salt supply that have shaped the diapir. In two dimensions......, In this study we compare results of analogue and numerical models of diapirs with two natural salt diapris (Klodawa and Gorleben diapirs) to explain their salt supply and asymmetric evolution. In a NW-SE section, the Gorleben salt diapir possesses an asymmetric external geometry represented by a large...... southeastern overhang due to salt extrusion during Middle Cretaceous followed by its burial in Tertiary. This external asymmetry is also reflected in the internal configuration of the diapir which shows different rates of salt flow on the two halves of the structure. The asymmetric external and internal...

  1. A Study on the Coupled Model of Hydrothermal-Salt for Saturated Freezing Salinized Soil

    Directory of Open Access Journals (Sweden)

    Xudong Zhang

    2017-01-01

    Full Text Available Water and heat interact in the process of freezing for the saturated soil. And for the salinized soil, water, heat, and salt interact in the freezing process, because salinized soil has soluble salt. In this paper, a one-dimensional mathematical coupled model of hydraulic-thermal-salt is established. In the model, Darcy’s law, law of conservation of energy, and law of conservation of mass are applied to derive the equations. Consider that a saturated salinized soil column is subjected to the condition of freezing to model the moisture migration and salt transport. Both experiment and numerical simulation under the same condition are developed in the soil column. Then the moisture content and salt content between simulation and experiment are compared. The result indicates that simulation matches well with the experiment data, and after 96 hours, the temperature distribution becomes stable, freezing front reaches a stable position, and a lot of unfrozen water has time to migrate. Besides, the excess salt precipitates when the concentration is greater than the solubility, and the precipitation is distributed discontinuously. These results can provide reference for engineering geology and environmental engineering in cold region and saline soil area.

  2. Halide salts and their structural properties in presence of secondary amine based molecule: A combined experimental and theoretical analysis

    Science.gov (United States)

    Ghosh, Pritam; Hazra, Abhijit; Ghosh, Meenakshi; Chandra Murmu, Naresh; Banerjee, Priyabrata

    2018-04-01

    Biologically relevant halide salts and its solution state structural properties are always been significant. In general, exposure of halide salts into polar solution medium results in solvation which in turn separates the cationic and anionic part of the salt. However, the conventional behaviour of salts might alter in presence of any secondary amine based compound, i.e.; moderately strong Lewis acid. In its consequence, to investigate the effect of secondary amine based compound in the salt solution, novel (E)-2-(4-bromobenzylidene)-1-(perfluorophenyl) hydrazine has been synthesized and used as secondary amine source. The secondary amine compound interestingly shows a drastic color change upon exposure to fluoride salts owing to hydrogen bonding interaction. Several experimental methods, e.g.; SCXRD, UV-Vis, FT-IR, ESI-MS and DLS together with modern DFT (i.e.; DFT-D3) have been performed to explore the structural properties of the halide salts upon exposure to secondary amine based compound. The effect of counter cation of the fluoride salt in binding with secondary amine source has also been investigated.

  3. SUPPRESSING DIFFRACTION EFFECT USING KIRCHHOFF PRE-STACK TIME MIGRATION ON 2D SEISMIC MULTICHANNEL DATA AT FLORES SEA

    Directory of Open Access Journals (Sweden)

    Tumpal Benhard Nainggolan

    2017-07-01

    Full Text Available 2D seismic multichannel survey has been carried out by Marine Geological Institute of Indonesia to interpret imaging and sub-surface geological information in the Flores Sea. Seismic data processing starts from pre-processing until migration stage. Migration is an important stage in the seismic processing, because at this stage the effects of diffraction and oblique reflectors caused by fault, salt domes, wedging, etc. will be repositioned to the actual points. One example of diffraction effects can be seen on the seismic section of a conventional stacking that have not migrated, i.e. resulting in an apparent bowtie reflector. Geologists find difficulties in interpreting geological information from diffracted seismic section, so it needs further processing to overcome the effects. By using Kirchhoff method and carried out during the Pre-Stack Time Migration (PSTM, this method turns out to produce migrated seismic section which is much better than conventional stacked one. This is due to the Kirchhoff method suppressed the identified diffraction effects, so that the geologist can interpret geological structure of the resulting migrated seismic section of the Flores Sea.

  4. Acemetacin cocrystals and salts: structure solution from powder X-ray data and form selection of the piperazine salt

    Directory of Open Access Journals (Sweden)

    Palash Sanphui

    2014-03-01

    Full Text Available Acemetacin (ACM is a non-steroidal anti-inflammatory drug (NSAID, which causes reduced gastric damage compared with indomethacin. However, acemetacin has a tendency to form a less soluble hydrate in the aqueous medium. We noted difficulties in the preparation of cocrystals and salts of acemetacin by mechanochemical methods, because this drug tends to form a hydrate during any kind of solution-based processing. With the objective to discover a solid form of acemetacin that is stable in the aqueous medium, binary adducts were prepared by the melt method to avoid hydration. The coformers/salt formers reported are pyridine carboxamides [nicotinamide (NAM, isonicotinamide (INA, and picolinamide (PAM], caprolactam (CPR, p-aminobenzoic acid (PABA, and piperazine (PPZ. The structures of an ACM–INA cocrystal and a binary adduct ACM–PABA were solved using single-crystal X-ray diffraction. Other ACM cocrystals, ACM–PAM and ACM–CPR, and the piperazine salt ACM–PPZ were solved from high-resolution powder X-ray diffraction data. The ACM–INA cocrystal is sustained by the acid...pyridine heterosynthon and N—H...O catemer hydrogen bonds involving the amide group. The acid...amide heterosynthon is present in the ACM–PAM cocrystal, while ACM–CPR contains carboxamide dimers of caprolactam along with acid–carbonyl (ACM hydrogen bonds. The cocrystals ACM–INA, ACM–PAM and ACM–CPR are three-dimensional isostructural. The carboxyl...carboxyl synthon in ACM–PABA posed difficulty in assigning the position of the H atom, which may indicate proton disorder. In terms of stability, the salts were found to be relatively stable in pH 7 buffer medium over 24 h, but the cocrystals dissociated to give ACM hydrate during the same time period. The ACM–PPZ salt and ACM–nicotinamide cocrystal dissolve five times faster than the stable hydrate form, whereas the ACM–PABA adduct has 2.5 times faster dissolution rate. The pharmaceutically acceptable

  5. Acemetacin cocrystals and salts: structure solution from powder X-ray data and form selection of the piperazine salt.

    Science.gov (United States)

    Sanphui, Palash; Bolla, Geetha; Nangia, Ashwini; Chernyshev, Vladimir

    2014-03-01

    Acemetacin (ACM) is a non-steroidal anti-inflammatory drug (NSAID), which causes reduced gastric damage compared with indomethacin. However, acemetacin has a tendency to form a less soluble hydrate in the aqueous medium. We noted difficulties in the preparation of cocrystals and salts of acemetacin by mechanochemical methods, because this drug tends to form a hydrate during any kind of solution-based processing. With the objective to discover a solid form of acemetacin that is stable in the aqueous medium, binary adducts were prepared by the melt method to avoid hydration. The coformers/salt formers reported are pyridine carboxamides [nicotinamide (NAM), isonicotinamide (INA), and picolinamide (PAM)], caprolactam (CPR), p-aminobenzoic acid (PABA), and piperazine (PPZ). The structures of an ACM-INA cocrystal and a binary adduct ACM-PABA were solved using single-crystal X-ray diffraction. Other ACM cocrystals, ACM-PAM and ACM-CPR, and the piperazine salt ACM-PPZ were solved from high-resolution powder X-ray diffraction data. The ACM-INA cocrystal is sustained by the acid⋯pyridine heterosynthon and N-H⋯O catemer hydrogen bonds involving the amide group. The acid⋯amide heterosynthon is present in the ACM-PAM cocrystal, while ACM-CPR contains carboxamide dimers of caprolactam along with acid-carbonyl (ACM) hydrogen bonds. The cocrystals ACM-INA, ACM-PAM and ACM-CPR are three-dimensional isostructural. The carboxyl⋯carboxyl synthon in ACM-PABA posed difficulty in assigning the position of the H atom, which may indicate proton disorder. In terms of stability, the salts were found to be relatively stable in pH 7 buffer medium over 24 h, but the cocrystals dissociated to give ACM hydrate during the same time period. The ACM-PPZ salt and ACM-nicotinamide cocrystal dissolve five times faster than the stable hydrate form, whereas the ACM-PABA adduct has 2.5 times faster dissolution rate. The pharmaceutically acceptable piperazine salt of acemetacin exhibits superior

  6. A Study on Salt Attack Protection of Structural and Finishing Materials in Power Plant Structures

    Energy Technology Data Exchange (ETDEWEB)

    Kim, W.B.; Kweon, K.J.; Suh, Y.P.; Nah, H.S.; Lee, K.J.; Park, D.S.; Jo, Y.K. [Korea Electric Power Research Institute, Taejeon (Korea, Republic of)

    1997-12-31

    This is a final report written by both KEPRI and KICT as a co-operative research titled {sup A} study on Salt Protection of Structural and Finishings in Power Plant Structures{sup .} This study presented the methods to prevent the chloride-induced corrosion of power plant structures through collection and analysis of research datum relating to design, construction and maintenance for the prevention of structural and finishing materials, thru material performance tests for anti-corrosion under many kinds of chloride-induced corrosion environments. As a result, this study proposed the guidelines for design, construction and maintenance of power plant structures due to chloride-induced corrosion. (author). 257 refs., 111 figs., 86 tabs.

  7. A Study on Salt Attack Protection of Structural and Finishing Materials in Power Plant Structures

    Energy Technology Data Exchange (ETDEWEB)

    Kim, W B; Kweon, K J; Suh, Y P; Nah, H S; Lee, K J; Park, D S; Jo, Y K [Korea Electric Power Research Institute, Taejeon (Korea, Republic of)

    1998-12-31

    This is a final report written by both KEPRI and KICT as a co-operative research titled {sup A} study on Salt Protection of Structural and Finishings in Power Plant Structures{sup .} This study presented the methods to prevent the chloride-induced corrosion of power plant structures through collection and analysis of research datum relating to design, construction and maintenance for the prevention of structural and finishing materials, thru material performance tests for anti-corrosion under many kinds of chloride-induced corrosion environments. As a result, this study proposed the guidelines for design, construction and maintenance of power plant structures due to chloride-induced corrosion. (author). 257 refs., 111 figs., 86 tabs.

  8. Romanian experience with rock salt characterisation methods and the implications for disposal of spent nuclear fuel

    International Nuclear Information System (INIS)

    Diaconu, Daniela; Balan, Valeriu; Mirion, Ilie

    2001-01-01

    The disposal in deep geological formations as rock salt, granite or clay seems to be now the most appropriate solution for final storage of the spent fuel. At this moment, rock salt is one of the Romanian options for spent fuel disposal, but the final decision will be made only after a performance assessment of this geological formation, having as input data the specific characteristics of the salt rock. In order to provide the data requested by the safety assessment programs, the Institute for Nuclear Research - Pitesti developed complex and modern methodologies for thermodynamic parameter determination as well as studies on salt convergence and radionuclide migration. The methodologies pursued to determine those thermal properties specific for spent fuel disposal as dilatation coefficient, heat conductivity and specific heat. The convergence and migration studies pursued a better understanding of these processes, very important in the disposal safety. The paper is a review of those studies and presents the methodologies and the main results obtained on salt samples from Slanic Prahova Salt Mine. (authors)

  9. Structural study of salt forms of amides; paracetamol, benzamide and piperine

    Science.gov (United States)

    Kennedy, Alan R.; King, Nathan L. C.; Oswald, Iain D. H.; Rollo, David G.; Spiteri, Rebecca; Walls, Aiden

    2018-02-01

    Single crystal x-ray diffraction has been used to investigate the structures of six complexes containing O-atom protonated cations derived from the pharmaceutically relevant amides benzamide (BEN), paracetamol (PAR) and piperine (PIP). The structures of the salt forms [PAR(H)][SO3C6H4Cl], [BEN(H)][O3SC6H4Cl] and [BEN(H)][Br]·H2O are reported along with those of the hemi-halide salt forms [PAR(H)][I3]. PAR, [PIP(H)][I3]·PIP and [PIP(H)][I3]0·5[I]0.5. PIP. The structure of the cocrystal BEN. HOOCCH2Cl is also presented for comparison. The geometry of the amide group is found to systematically change upon protonation, with the Cdbnd O distance increasing and the Csbnd N distance decreasing. The hemi-halide species all feature strongly hydrogen bonded amide(H)/amide pairs. The amide group Cdbnd O and Csbnd N distances for both elements of each such pair are intermediate between those found for simple neutral amide and protonated amide forms. It was found that crystallising paracetamol from aqueous solutions containing Ba2+ ions gave orthorhombic paracetamol.

  10. Structure of tungsten electrodeposited from oxide chloride-fluoride molten salts

    International Nuclear Information System (INIS)

    Pavlovskij, V.A.; Reznichenko, V.A.

    1998-01-01

    Investigation results on the influence of electrolysis parameters and electrolyte composition on tungsten cathode deposit structure are presented. The electrolysis was performed in NaCl-NaF-WO 3 molten salts using tungsten and tungsten coated molybdenum cathodes. Morphological and metallographic studies of tungsten crystals were carrier out. Tungsten deposits were obtained in the form of crystalline conglomerates, sponge and high dispersity powder

  11. Introducing improved structural properties and salt dependence into a coarse-grained model of DNA

    Energy Technology Data Exchange (ETDEWEB)

    Snodin, Benedict E. K., E-mail: benedict.snodin@chem.ox.ac.uk; Mosayebi, Majid; Schreck, John S.; Romano, Flavio; Doye, Jonathan P. K., E-mail: jonathan.doye@chem.ox.ac.uk [Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ (United Kingdom); Randisi, Ferdinando [Life Sciences Interface Doctoral Training Center, South Parks Road, Oxford OX1 3QU (United Kingdom); Rudolf Peierls Centre for Theoretical Physics, 1 Keble Road, Oxford OX1 3NP (United Kingdom); Šulc, Petr [Center for Studies in Physics and Biology, The Rockefeller University, 1230 York Avenue, New York, New York 10065 (United States); Ouldridge, Thomas E. [Department of Mathematics, Imperial College, 180 Queen’s Gate, London SW7 2AZ (United Kingdom); Tsukanov, Roman; Nir, Eyal [Department of Chemistry and the Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer Sheva (Israel); Louis, Ard A. [Rudolf Peierls Centre for Theoretical Physics, 1 Keble Road, Oxford OX1 3NP (United Kingdom)

    2015-06-21

    We introduce an extended version of oxDNA, a coarse-grained model of deoxyribonucleic acid (DNA) designed to capture the thermodynamic, structural, and mechanical properties of single- and double-stranded DNA. By including explicit major and minor grooves and by slightly modifying the coaxial stacking and backbone-backbone interactions, we improve the ability of the model to treat large (kilobase-pair) structures, such as DNA origami, which are sensitive to these geometric features. Further, we extend the model, which was previously parameterised to just one salt concentration ([Na{sup +}] = 0.5M), so that it can be used for a range of salt concentrations including those corresponding to physiological conditions. Finally, we use new experimental data to parameterise the oxDNA potential so that consecutive adenine bases stack with a different strength to consecutive thymine bases, a feature which allows a more accurate treatment of systems where the flexibility of single-stranded regions is important. We illustrate the new possibilities opened up by the updated model, oxDNA2, by presenting results from simulations of the structure of large DNA objects and by using the model to investigate some salt-dependent properties of DNA.

  12. Introducing improved structural properties and salt dependence into a coarse-grained model of DNA

    International Nuclear Information System (INIS)

    Snodin, Benedict E. K.; Mosayebi, Majid; Schreck, John S.; Romano, Flavio; Doye, Jonathan P. K.; Randisi, Ferdinando; Šulc, Petr; Ouldridge, Thomas E.; Tsukanov, Roman; Nir, Eyal; Louis, Ard A.

    2015-01-01

    We introduce an extended version of oxDNA, a coarse-grained model of deoxyribonucleic acid (DNA) designed to capture the thermodynamic, structural, and mechanical properties of single- and double-stranded DNA. By including explicit major and minor grooves and by slightly modifying the coaxial stacking and backbone-backbone interactions, we improve the ability of the model to treat large (kilobase-pair) structures, such as DNA origami, which are sensitive to these geometric features. Further, we extend the model, which was previously parameterised to just one salt concentration ([Na + ] = 0.5M), so that it can be used for a range of salt concentrations including those corresponding to physiological conditions. Finally, we use new experimental data to parameterise the oxDNA potential so that consecutive adenine bases stack with a different strength to consecutive thymine bases, a feature which allows a more accurate treatment of systems where the flexibility of single-stranded regions is important. We illustrate the new possibilities opened up by the updated model, oxDNA2, by presenting results from simulations of the structure of large DNA objects and by using the model to investigate some salt-dependent properties of DNA

  13. Containment of solidified liquid hazardous waste in domal salt

    International Nuclear Information System (INIS)

    Domenico, P.A.; Lerman, A.

    1992-01-01

    In recent years, the solidification of hazardous liquid waste has become a viable option in waste management. The solidification process results in an increased volume but more stable waste form that must be disposed of or stored in a dry environment. An environment of choice in south central Texas is domal salt. The salt dome currently under investigation has a water content of 0.002 percent by weight and a permeability less than one nanodarcy. A question that must be addressed is whether a salt dome has a particular set of attributes that will prevent the release of contaminants to the environment. From a regulatory perspective, a ''no migration'' petition must be approved by the U.S.E.P.A. for the containment facility. By ''no migration'' it is implied that the waste must be contained for 10,000 years. A demonstration that this condition will be met will require model calculations and such models must be based on the physical and chemical characteristics of the waste form and the geologic environment. In particular, the models must address the rate of brine infiltration into the caverns, providing information on how fast an immobile solid waste form could convert to a more mobile liquid state. Additionally, the potential for migration by both diffusion and advection is of concern. Lastly, given a partially saturated cavern, the question of how far gaseous waste will be transported over the 10,000 year containment period must also be addressed. Results indicate that the containment capabilities of domal salt are exceptional. A nominal volume of brine will seep into the cavern and most voids between the injected solidified waste pellets will remain unsaturated. Very small quantities of hazardous constituents will be leached from the waste pellets

  14. Tidal events and salt-marsh structure influence black mangrove (Avicennia germinans) recruitment across an ecotone.

    Science.gov (United States)

    Peterson, Jennifer M; Bell, Susan S

    2012-07-01

    Field experiments were conducted at a black mangrove-salt-marsh ecotone in southwest Florida (U.S.A.) to investigate retention of propagules of the black mangrove, Avicennia germinans, by salt-marsh plants as a mechanism of facilitation operating on recruitment success at landward boundaries. Buoyant A. germinans propagules are dispersed by tides, and stranding is required for establishment; therefore, processes that enable stranding should facilitate mangrove recruitment. We expected the physical structure of salt-marsh vegetation to define propagule retention capacity, and we predicted that salt-marsh plants with distinct growth forms would differentially retain propagules. Experimental monoculture plots (1 m2) of salt-marsh plants with different growth forms (Sporobolus virginicus [grass], Sesuvium portulacastrum [succulent forb], and Batis maritima [succulent scrub]) were created, and A. germinans propagules were emplaced into these plots and monitored over time. For comparison, propagules were also placed into natural polyculture plots (1 m2). Polyculture plots contained at least two of the salt-marsh plant taxa selected for monoculture treatments, and S. virginicus was always present within these polyculture plots. Natural polyculture plots retained 59.3% +/- 11.0% (mean +/- SE) of emplaced propagules. Monocultures varied in their propagule retention capacities with plots of S. virginicus retaining on average 65.7% +/- 11.5% of transplanted propagules compared to 7.2% +/- 1.8% by B. maritima and 5.0% +/- 1.9% by S. portulacastrum. Plots containing S. virginicus retained a significantly greater percentage of emplaced propagules relative to the two succulent salt-marsh taxa. Furthermore, propagule entrapment, across all treatments, was strongly correlated with salt-marsh structure (r2 = 0.6253, P = 0.00001), which was estimated using an indirect quantitative metric (lateral obstruction) calculated from digital images of plots. Overall, our findings imply that

  15. Juridical structures: refugees and migration.

    Science.gov (United States)

    Veiter, T

    1988-01-01

    The juridical problems in regard to the concepts of refugee, expulsion, and migration are complicated. If one speaks about migration in Europe, one must 1st distinguish between Eastern and Western Europe. In the communist states of Eastern Europe the refugee problem does not exist officially, with the only existing refugee problem in Yugoslavia, which has signed and ratified the Geneva Refugee Convention of 1951. In the other East European states the right to asylum exists, but refugees are granted asylum only if they are persecuted in their country of origin for their communist ideas and activities. In speaking of migration, one must distinguish between migration, forced migration, mass migration, emigration, immigration, the shift of populations, and refugees. In the communist countries of Eastern Europe the right to emigration is not respected, although certain exceptions, as in Poland or Yugoslavia do exist. Generally, in the communist states emigration is not allowed and illegal emigration is punished as "Flight from the Republic." With a few exceptions, political and other persecutions are no longer so typical within Europe. In the last decades, the refugee problem has changed to other continents: Afghanistan/Pakistan, Iran, Sri Lanka, East Timor, Lebanon, Palestine, Sudan, Tchad, Ethiopia, Eritrea, and Angola. The refugee problem in Europe consists mainly in the large afflux of refugees coming from places with other cultural (and religious) attributes. The Islamic immigrants declare themselves regularly as political refugees and hope to be acknowledged as such by the receiving state. The fear of the governments and populations of the receiving countries is that it would not be possible to assimilate such aliens who do not belong to the Christian culture of Europe. Formerly, refugees came mostly from the Christian countries of Eastern Europe with the same race identity and the same religion. For years now, more and more foreign workers are a kind of migrant

  16. Structure of eight molecular salts assembled from noncovalent bonding between carboxylic acids, imidazole, and benzimidazole

    Science.gov (United States)

    Jin, Shouwen; Zhang, Huan; Liu, Hui; Wen, Xianhong; Li, Minghui; Wang, Daqi

    2015-09-01

    Eight organic salts of imidazole/benzimidazole have been prepared with carboxylic acids as 2-methyl-2-phenoxypropanoic acid, α-ketoglutaric acid, 5-nitrosalicylic acid, isophthalic acid, 4-nitro-phthalic acid, and 3,5-dinitrosalicylic acid. The eight crystalline forms reported are proton-transfer compounds of which the crystals and compounds were characterized by X-ray diffraction analysis, IR, mp, and elemental analysis. These structures adopted hetero supramolecular synthons, with the most common R22(7) motif observed at salts 2, 3, 5, 6 and 8. Analysis of the crystal packing of 1-8 suggests that there are extensive strong Nsbnd H⋯O, and Osbnd H⋯O hydrogen bonds (charge assisted or neutral) between acid and imidazolyl components in all of the salts. Except the classical hydrogen bonding interactions, the secondary propagating interactions also play important roles in structure extension. This variety, coupled with the varying geometries and number of acidic groups of the acids utilized, has led to the creation of eight supramolecular arrays with 1D-3D structure. The role of weak and strong noncovalent interactions in the crystal packing is analyzed. The results presented herein indicate that the strength and directionality of the Nsbnd H⋯O, and Osbnd H⋯O hydrogen bonds between acids and imidazole/benzimidazole are sufficient to bring about the formation of organic salts.

  17. Structure and ionic conductivity of block copolymer electrolytes over a wide salt concentration range

    Science.gov (United States)

    Chintapalli, Mahati; Le, Thao; Venkatesan, Naveen; Thelen, Jacob; Rojas, Adriana; Balsara, Nitash

    Block copolymer electrolytes are promising materials for safe, long-lasting lithium batteries because of their favorable mechanical and ion transport properties. The morphology, phase behavior, and ionic conductivity of a block copolymer electrolyte, SEO mixed with LiTFSI was studied over a wide, previously unexplored salt concentration range using small angle X-ray scattering, differential scanning calorimetry and ac impedance spectroscopy, respectively. SEO exhibits a maximum in ionic conductivity at twice the salt concentration that PEO, the homopolymer analog of the ion-containing block, does. This finding is contrary to prior studies that examined a more limited range of salt concentrations. In SEO, the phase behavior of the PEO block and LiTFSI closely resembles the phase behavior of homopolymer PEO and LiTFSI. The grain size of the block copolymer morphology was found to decrease with increasing salt concentration, and the ionic conductivity of SEO correlates with decreasing grain size. Structural effects impact the ionic conductivity-salt concentration relationship in block copolymer electrolytes. SEO: polystyrene-block-poly(ethylene oxide); also PS-PEO LiTFSI: lithium bis(trifluoromethanesulfonyl imide

  18. Estimates of future inundation of salt marshes in response to sea-level rise in and around Acadia National Park, Maine

    Science.gov (United States)

    Nielsen, Martha G.; Dudley, Robert W.

    2013-01-01

    Salt marshes are ecosystems that provide many important ecological functions in the Gulf of Maine. The U.S. Geological Survey investigated salt marshes in and around Acadia National Park from Penobscot Bay to the Schoodic Peninsula to map the potential for landward migration of marshes using a static inundation model of a sea-level rise scenario of 60 centimeters (cm; 2 feet). The resulting inundation contours can be used by resource managers to proactively adapt to sea-level rise by identifying and targeting low-lying coastal areas adjacent to salt marshes for conservation or further investigation, and to identify risks to infrastructure in the coastal zone. For this study, the mapping of static inundation was based on digital elevation models derived from light detection and ranging (LiDAR) topographic data collected in October 2010. Land-surveyed control points were used to evaluate the accuracy of the LiDAR data in the study area, yielding a root mean square error of 11.3 cm. An independent accuracy assessment of the LiDAR data specific to salt-marsh land surfaces indicated a root mean square error of 13.3 cm and 95-percent confidence interval of ± 26.0 cm. LiDAR-derived digital elevation models and digital color aerial photography, taken during low tide conditions in 2008, with a pixel resolution of 0.5 meters, were used to identify the highest elevation of the land surface at each salt marsh in the study area. Inundation contours for 60-cm of sea-level rise were delineated above the highest marsh elevation for each marsh. Confidence interval contours (95-percent,± 26.0 cm) were delineated above and below the 60-cm inundation contours, and artificial structures, such as roads and bridges, that may present barriers to salt-marsh migration were mapped. This study delineated 114 salt marshes totaling 340 hectares (ha), ranging in size from 0.11 ha (marshes less than 0.2 ha were mapped only if they were on Acadia National Park property) to 52 ha, with a median

  19. Hydrogen impurity in SrTiO3: structure, electronic properties and migration

    International Nuclear Information System (INIS)

    Villamagua, Luis; Barreto, Rafael; Procel, Luis Miguel; Stashans, Arvids

    2007-01-01

    The present paper reports a computational investigation of the geometry and electronic structure as well as the migration of a hydrogen impurity in the cubic SrTiO 3 crystal. The study is done using an approach based on the Hartree-Fock theory and developed for periodic systems. It is found that the H impurity forms the so-called OH group at the equilibrium. Analysis of electron density within the defective region implies the enhancement in covalent chemical bonding. A possible defect migration has been also investigated

  20. Phylodynamics with Migration: A Computational Framework to Quantify Population Structure from Genomic Data.

    Science.gov (United States)

    Kühnert, Denise; Stadler, Tanja; Vaughan, Timothy G; Drummond, Alexei J

    2016-08-01

    When viruses spread, outbreaks can be spawned in previously unaffected regions. Depending on the time and mode of introduction, each regional outbreak can have its own epidemic dynamics. The migration and phylodynamic processes are often intertwined and need to be taken into account when analyzing temporally and spatially structured virus data. In this article, we present a fully probabilistic approach for the joint reconstruction of phylodynamic history in structured populations (such as geographic structure) based on a multitype birth-death process. This approach can be used to quantify the spread of a pathogen in a structured population. Changes in epidemic dynamics through time within subpopulations are incorporated through piecewise constant changes in transmission parameters.We analyze a global human influenza H3N2 virus data set from a geographically structured host population to demonstrate how seasonal dynamics can be inferred simultaneously with the phylogeny and migration process. Our results suggest that the main migration path among the northern, tropical, and southern region represented in the sample analyzed here is the one leading from the tropics to the northern region. Furthermore, the time-dependent transmission dynamics between and within two HIV risk groups, heterosexuals and injecting drug users, in the Latvian HIV epidemic are investigated. Our analyses confirm that the Latvian HIV epidemic peaking around 2001 was mainly driven by the injecting drug user risk group. © The Author 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  1. Influence of a solvent on thermodynamics of electrolytic dissociation of simple and complex rare earth salts

    Energy Technology Data Exchange (ETDEWEB)

    Gorodyskij, A.V.; Fialkov, Yu.Ya.; Chernyj, D.B. (AN Ukrainskoj SSR, Kiev. Inst. Obshchej i Neorganicheskoj Khimii; Kievskij Politekhnicheskij Inst. (Ukrainian SSR))

    1982-03-01

    Influence of the double mixed solvent on thermodynamic characteristics of ionic migration of lanthanum, neodymium, europium and dysprosium chlorides as well as their phenanthroline complexes is considered. Decrease of lambdasub(c) of simple and complex rare earth salts in the lanthanum, neodymium-europium-dysprosium series as explained by increase of solvation degree, associated with lanthanum compression. It is shown that increase of methanol or propanol content results in exothermicity decrease of the ionic migration process. The temperature constituents of enthalpy and entropy of dissociation of the simple and complex rare earth salts are presented.

  2. Protective role of salt in catalysis and maintaining structure of halophilic proteins against denaturation

    Science.gov (United States)

    Sinha, Rajeshwari; Khare, Sunil K.

    2014-01-01

    Search for new industrial enzymes having novel properties continues to be a desirable pursuit in enzyme research. The halophilic organisms inhabiting under saline/ hypersaline conditions are considered as promising source of useful enzymes. Their enzymes are structurally adapted to perform efficient catalysis under saline environment wherein n0n-halophilic enzymes often lose their structure and activity. Haloenzymes have been documented to be polyextremophilic and withstand high temperature, pH, organic solvents, and chaotropic agents. However, this stability is modulated by salt. Although vast amount of information have been generated on salt mediated protection and structure function relationship in halophilic proteins, their clear understanding and correct perspective still remain incoherent. Furthermore, understanding their protein architecture may give better clue for engineering stable enzymes which can withstand harsh industrial conditions. The article encompasses the current level of understanding about haloadaptations and analyzes structural basis of their enzyme stability against classical denaturants. PMID:24782853

  3. Multi-source least-squares reverse time migration

    KAUST Repository

    Dai, Wei

    2012-06-15

    Least-squares migration has been shown to improve image quality compared to the conventional migration method, but its computational cost is often too high to be practical. In this paper, we develop two numerical schemes to implement least-squares migration with the reverse time migration method and the blended source processing technique to increase computation efficiency. By iterative migration of supergathers, which consist in a sum of many phase-encoded shots, the image quality is enhanced and the crosstalk noise associated with the encoded shots is reduced. Numerical tests on 2D HESS VTI data show that the multisource least-squares reverse time migration (LSRTM) algorithm suppresses migration artefacts, balances the amplitudes, improves image resolution and reduces crosstalk noise associated with the blended shot gathers. For this example, the multisource LSRTM is about three times faster than the conventional RTM method. For the 3D example of the SEG/EAGE salt model, with a comparable computational cost, multisource LSRTM produces images with more accurate amplitudes, better spatial resolution and fewer migration artefacts compared to conventional RTM. The empirical results suggest that multisource LSRTM can produce more accurate reflectivity images than conventional RTM does with a similar or less computational cost. The caveat is that the LSRTM image is sensitive to large errors in the migration velocity model. © 2012 European Association of Geoscientists & Engineers.

  4. Multi-source least-squares reverse time migration

    KAUST Repository

    Dai, Wei; Fowler, Paul J.; Schuster, Gerard T.

    2012-01-01

    Least-squares migration has been shown to improve image quality compared to the conventional migration method, but its computational cost is often too high to be practical. In this paper, we develop two numerical schemes to implement least-squares migration with the reverse time migration method and the blended source processing technique to increase computation efficiency. By iterative migration of supergathers, which consist in a sum of many phase-encoded shots, the image quality is enhanced and the crosstalk noise associated with the encoded shots is reduced. Numerical tests on 2D HESS VTI data show that the multisource least-squares reverse time migration (LSRTM) algorithm suppresses migration artefacts, balances the amplitudes, improves image resolution and reduces crosstalk noise associated with the blended shot gathers. For this example, the multisource LSRTM is about three times faster than the conventional RTM method. For the 3D example of the SEG/EAGE salt model, with a comparable computational cost, multisource LSRTM produces images with more accurate amplitudes, better spatial resolution and fewer migration artefacts compared to conventional RTM. The empirical results suggest that multisource LSRTM can produce more accurate reflectivity images than conventional RTM does with a similar or less computational cost. The caveat is that the LSRTM image is sensitive to large errors in the migration velocity model. © 2012 European Association of Geoscientists & Engineers.

  5. Solution, thermal and optical properties of bis(pyridinium salt)s as ionic liquids

    International Nuclear Information System (INIS)

    Jo, Tae Soo; Koh, Jung Jae; Han, Haesook; Bhowmik, Pradip K.

    2013-01-01

    Bis(pyridinium salt)s containing different alkyl chain lengths and various organic counterions were prepared by the ring-transmutation reaction of bis(pyrylium tosylate) with aliphatic amines in dimethyl sulfoxide at 130–135 °C for 18 h and their tosylate counterions were exchanged to other anions such as triflimide, methyl orange, and dioctyl sulfosuccinate by the metathesis reaction in a common organic solvent. Their chemical structures were established by using 1 H, 19 F, and 13 C NMR spectra. The thermal properties of bis(pyridinium salt)s were studied by DSC and TGA measurements. Some of the dicationic salts provided low melting points below 100 °C and some of them displayed amorphous properties. Polarized optical microscopy studies revealed the crystal structures prior to melting temperatures in some cases. Their optical properties were examined by using UV–Vis and photoluminescent spectrometers; and they emitted blue light both in the solution and solid states regardless of their microstructures, counterions, and the polarity of organic solvents. However, most of these salts exhibited hypsochromic shifts in their emission peaks in the solid state when compared with those of their solution spectra. Due to unique properties of methyl orange anion as a pH indicator, two of the salts showed different color change in varying concentrations of triflic acid in common organic solvents, demonstrating their potential use as an acid sensor in methanol, acetonitrile and acetone. Highlights: ► Luminescent dicationic salts were synthesized by ring-transmutation and metathesis reactions. ► Thermal and optical properties of dicationic salts are affected by the size of anion structures. ► Due to the methyl orange counterions, some dicationic salts showed pH- sensing property

  6. Numerical estimation of structural integrity of salt cavern wells.

    NARCIS (Netherlands)

    Orlic, B.; Thienen-Visser, K. van; Schreppers, G.J.

    2016-01-01

    Finite element analyses were performed to estimate axial deformation of cavern wells due to gas storage operations in solution-mined salt caverns. Caverns shrink over time due to salt creep and the cavern roof subsides potentially threatening well integrity. Cavern deformation, deformation of salt

  7. Dissolution of the Upper Seven Rivers and Salado salt in the interior Palo Duro Basin, Texas: Revision: Topical report

    International Nuclear Information System (INIS)

    DeConto, R.T.; Murphy, P.J.

    1987-09-01

    The Upper Seven Rivers and Salado Formations contain the uppermost salts within the interior Palo Duro Basin, Stratigraphic and structural evidence based on geophysical well logs indicate that both dissolution and facies change have influenced the thickness of these uppermost salts. The magnitude of vertical salt loss due to dissolution is interminable at this time because original salt thickness is unknown. Gradual thinning of the Upper Seven Rivers Formation is recognized from south to north across the Palo Duro Basin. Anhydrites within the formation pinch out toward the basin margins, indicating that section loss is in part depositionally controlled. Additionally, informal subdivision of the Upper Seven Rivers Formation suggests that salt dissolution has occurred in the uppermost salt. A northeast-trending zone of thin Upper Seven Rivers Formation in portions of Deaf Smith, Randall, Castro, and Parmer Counties is possibly related to Tertiary dissolution. In New Mexico, local thinning of the Upper Seven Rivers Formation may be associated with faulting. Triassic erosion on uplifted fault blocks has affected the Upper Permian section. The Salado salt margin is located within the interior Palo Duro Basin. Geophysical well logs and core evidence indicate that the salt margin has migrated basinward as a result of dissolution. Permian dissolution probably contributed to some salt loss. 106 refs., 31 figs., 2 tabs

  8. Changes in ethnic structure of population in the light of recent trends of migration and natural reproduction

    Directory of Open Access Journals (Sweden)

    Novotný Ladislav

    2015-01-01

    Full Text Available The paper aims to assess the impact of migration and natural reproduction of population to the changes in ethnic structure of population by the case study of three multi-ethnic functional urban regions in Slovakia. All three regions are located at the Slovak-Hungarian ethnic border and are characterized by larger proportion of Slovaks and lower proportion of Hungarians in the core than in the ring. The regions were chosen also with intent to provide a sample with various processes of spatial redistribution of population taking place, which are described in the paper. The ethnic structure at the levels of whole regions, their basic components - cores and rings - is introduced briefly. The analyses of changes in the ethnic structure and its relationships with the natural reproduction and migration of population provides interesting results. It was proved that the migration is a driving force in changes of ethnic structure in analysed regions, even though the patterns of natural reproduction behaviors between ethnic Slovaks and Hungarians are traditionally different. Since the most intensive process of spatial redistribution of population is the decentralization from the cores to the rings of the regions driven by migration, the ethnic structure of the rings tends to approximate to that in the cores.

  9. Molten salt breeder reactor

    International Nuclear Information System (INIS)

    1977-01-01

    MSBR Study Group formed in October 1974 has studied molten salt breeder reactor and its various aspects. Usage of a molten salt fuel, extremely interesting as reactor chemistry, is a great feature to MSBR; there is no need for separate fuel making, reprocessing, waste storage facilities. The group studied the following, and these results are presented: molten salt technology, molten salt fuel chemistry and reprocessing, reactor characteristics, economy, reactor structural materials, etc. (Mori, K.)

  10. Lattice stability of metastable AlN and wurtzite-to-rock-salt structural transformation by CALPHAD modeling

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yanhui, E-mail: yanhui.z@hotmail.com [Karlsruhe Institute of Technology (KIT), Institute for Applied Materials-Applied Materials Physics (IAM-AWP), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); High-performance Ceramics Division, Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 110016, Shenyang (China); Franke, Peter; Li, Dajian; Seifert, Hans Jürgen [Karlsruhe Institute of Technology (KIT), Institute for Applied Materials-Applied Materials Physics (IAM-AWP), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)

    2016-12-01

    Reliable lattice stability of cubic AlN with rock-salt structure (rs-AlN) is the prerequisite of accurate thermodynamic modeling of cubic (M, Al)N solid solutions (M = Ti, Zr, Cr etc.). In order to derive the Gibbs energy of metastable rs-AlN, and then its lattice stability, we did the pressure-temperature (P-T) assessment of AlN phases by equations-of-state modeling. Meanwhile, the molar volumes and the heat capacities of wurtzite and rock-salt AlN, as well as the wurtzite-to-rock-salt structural transition at high P&T were successfully incorporated in CALPHAD-type database by integrating thermodynamic data from experiments and ab-initio calculations. These results promise subsequent investigations on phase stabilities and transitions of solid solutions with AlN component and the development of novel multicomponent coatings. - Highlights: • Phase stability investigation for novel multi-component metastable coatings. • Structural transition at high temperature and high pressure. • Integrating thermodynamic data from ab-initio calculations and experiments. • Thermal expansion, isothermal compressibility and heat capacity of w-AlN and rs-AlN.

  11. Meisoindigo, but not its core chemical structure indirubin, inhibits zebrafish interstitial leukocyte chemotactic migration.

    Science.gov (United States)

    Ye, Baixin; Xiong, Xiaoxing; Deng, Xu; Gu, Lijuan; Wang, Qiongyu; Zeng, Zhi; Gao, Xiang; Gao, Qingping; Wang, Yueying

    2017-12-01

    Inflammatory disease is a big threat to human health. Leukocyte chemotactic migration is required for efficient inflammatory response. Inhibition of leukocyte chemotactic migration to the inflammatory site has been shown to provide therapeutic targets for treating inflammatory diseases. Our study was designed to discover effective and safe compounds that can inhibit leukocyte chemotactic migration, thus providing possible novel therapeutic strategy for treating inflammatory diseases. In this study, we used transgenic zebrafish model (Tg:zlyz-EGFP line) to visualize the process of leukocyte chemotactic migration. Then, we used this model to screen the hit compound and evaluate its biological activity on leukocyte chemotactic migration. Furthermore, western blot analysis was performed to evaluate the effect of the hit compound on the AKT or ERK-mediated pathway, which plays an important role in leukocyte chemotactic migration. In this study, using zebrafish-based chemical screening, we identified that the hit compound meisoindigo (25 μM, 50 μM, 75 μM) can significantly inhibit zebrafish leukocyte chemotactic migration in a dose-dependent manner (p = 0.01, p = 0.0006, p migration (p = 0.43). Furthermore, our results unexpectedly showed that indirubin, the core structure of meisoindigo, had no significant effect on zebrafish leukocyte chemotactic migration (p = 0.6001). Additionally, our results revealed that meisoindigo exerts no effect on the Akt or Erk-mediated signalling pathway. Our results suggest that meisoindigo, but not indirubin, is effective for inhibiting leukocyte chemotactic migration, thus providing a potential therapeutic agent for treating inflammatory diseases.

  12. Mass transfer in a salt repository

    International Nuclear Information System (INIS)

    Pigford, T.H.; Chambre, P.L.

    1985-05-01

    To meet regulatory requirements for radioactive waste in a salt repository it is necessary to predict the rates of corrosion of the waste container, the release rates of radionuclides from the waste package, and the cumulative release of radionuclides into the accessible environment. The mechanisms that may control these rates and an approach to predicting these rates from mass-transfer theory are described. This new mechanistic approach is suggested by three premises: (a) a brine inclusion originally in a salt crystal moves along grain boundaries after thermal-induced migration out of the crystal, (b) brine moves along a grain boundary under the influence of a pressure gradient, and (c) salt surrounding a heat-generating waste package will soon creep and consolidate as a monolithic medium surrounding and in contact with the waste package. After consolidation there may be very little migration of intergranular and intragranular brine to the waste package. The corrosion rate of the waste container may then be limited by the rate at which brine reaches the container and may be calculable from mass-transfer theory, and the rate at which dissolved radionuclides leave the waste package may be limited by molecular diffusion in intragranular brine and may be calculable from mass-transfer theory. If porous nonsalt interbeds intersect the waste-package borehole, the release rate of dissolved radionuclides to interbed brine may also be calculable from mass-transfer theory. The logic of these conclusions is described, as an aid in formulating the calculations that are to be made

  13. Analog modeling and kinematic restoration of inverted hangingwall synclinal basins developed above syn-kinematic salt: Application to the Lusitanian and Parentis basins

    Science.gov (United States)

    Roma, Maria; Vidal-Royo, Oskar; McClay, Ken; Ferrer, Oriol; Muñoz, Josep Anton

    2017-04-01

    The formation of hagingwall syncline basins is basically constrained by the geometry of the basement-involved fault, but also by salt distribution . The formation of such basins is common around the Iberian Peninsula (e.g. Lusitanian, Parentis, Basque-Cantabian, Cameros and Organyà basins) where Upper Triassic (Keuper) salt governed their polyphasic Mesozoic extension and their subsequent Alpine inversion. In this scenario, a precise interpretation of the sub-salt faults geometry and a reconstruction of the initial salt thickness are key to understand the kinematic evolution of such basins. Using an experimental approach (sandbox models) and these Mesozoic basins as natural analogues, the aim of this work is to: 1) investigate the main parameters that controlled the formation and evolution of hagingwall syncline basins analyzing the role of syn-kinematic salt during extension and subsequent inversion; and 2) quantify the deformation and salt mobilization based on restoration of analog model cross sections. The experimental results demonstrate that premature welds are developed by salt deflation with consequent upward propagation of the basal fault in salt-bearing rift systems with a large amount of extension,. In contrast, thicker salt inhibits the upward fault propagation, which results into a further salt migration and development of a hagingwall syncline basins flanked by salt walls. The inherited extensional architecture as well as salt continuity dramatically controlled subsequent inversion. Shortening initially produced the folding and the uplift of the synclinal basins. Minor reverse faults form as a consequence of overtightening of welded diapir stems. However, no trace of reverse faulting is found around diapirs stems, as ductile unit is still available for extrusion, squeezing and accommodation of shortening. Restoration of the sandbox models has demonstrated that this is a powerful tool to unravel the complex structures in the models and this may

  14. Nuclear waste repository simulation experiments. Asse salt mine: Annual report 1984

    International Nuclear Information System (INIS)

    Rothfuchs, T.; Feddersen, H.K.; Schwarzianeck, P.; Staupendahl, G.; Coyle, A.J.; Kalia, H.; Eckert, J.

    1985-01-01

    This is the Second Annual Report (1984) which describes experiments simulating a nuclear waste repository at the 800 meter-level of the Asse Salt Mine in the Federal Republic of Germany. The report describes the Asse Salt Mine, the test equipment, and the pretest properties of the salt in the mine and in the vicinity of the test area. Also included are test data for the first sixteen months of operation on the following: brine migration rates, thermal mechanical behavior of the salt (including room closure, stress readings and thermal profiles) and borehole gas pressures. In addition to field data laboratory analyses of results are also included in this report. The duration of the experiment will be two years, ending in December 1985. (orig.)

  15. Brine migration test performed in the older Halite Na2β formation at the Asse salt mine. Temperature-test field No4(TTF4)

    International Nuclear Information System (INIS)

    Rothfuchs, T.; Schwarzianek, P.; Feddersen, H.

    1984-01-01

    A so-called brine migration test was performed in the Older Halite Na2β formation at the Asse salt mine. The test was designed to investigate the rate of thermally induced brine or crystalline water release into a heated borehole. The heat source simulates heat-producing high level radioactive waste. As a heat source a heater of 5,4 m length and 200 mm diameter was used in a 15 m deep vertical borehole. The initial heater power was 9000 Watt. Due to corrosion the heater power decreased during the experiment. The following measuring results were obtained: maximum salt temperature on heating day 137 = 280 0 C; average temperature gradient at the borehole wall on heating day 137 = 49 0 C/7,5 cm; accumulated water release on heating day 688 = 3386 g; pH-value of the condensate in the cool trap = 3; analysis of the borehole atmosphere: - no Cl 2 , SO 2 , HCl, H 2 S; - O 2 max 4%, CO max 0,3%, CO 2 max 12% and CH 4 max 1,3%. In addition to the investigation of the borehole atmosphere measurements of the local principle stresses and of the rock deformations were performed

  16. Ice crystallization in ultrafine water-salt aerosols: nucleation, ice-solution equilibrium, and internal structure.

    Science.gov (United States)

    Hudait, Arpa; Molinero, Valeria

    2014-06-04

    Atmospheric aerosols have a strong influence on Earth's climate. Elucidating the physical state and internal structure of atmospheric aqueous aerosols is essential to predict their gas and water uptake, and the locus and rate of atmospherically important heterogeneous reactions. Ultrafine aerosols with sizes between 3 and 15 nm have been detected in large numbers in the troposphere and tropopause. Nanoscopic aerosols arising from bubble bursting of natural and artificial seawater have been identified in laboratory and field experiments. The internal structure and phase state of these aerosols, however, cannot yet be determined in experiments. Here we use molecular simulations to investigate the phase behavior and internal structure of liquid, vitrified, and crystallized water-salt ultrafine aerosols with radii from 2.5 to 9.5 nm and with up to 10% moles of ions. We find that both ice crystallization and vitrification of the nanodroplets lead to demixing of pure water from the solutions. Vitrification of aqueous nanodroplets yields nanodomains of pure low-density amorphous ice in coexistence with vitrified solute rich aqueous glass. The melting temperature of ice in the aerosols decreases monotonically with an increase of solute fraction and decrease of radius. The simulations reveal that nucleation of ice occurs homogeneously at the subsurface of the water-salt nanoparticles. Subsequent ice growth yields phase-segregated, internally mixed, aerosols with two phases in equilibrium: a concentrated water-salt amorphous mixture and a spherical cap-like ice nanophase. The surface of the crystallized aerosols is heterogeneous, with ice and solution exposed to the vapor. Free energy calculations indicate that as the concentration of salt in the particles, the advance of the crystallization, or the size of the particles increase, the stability of the spherical cap structure increases with respect to the alternative structure in which a core of ice is fully surrounded by

  17. Synthesis, structural, solubility and anticancer activity studies of salts using nucleobases and sulfonic acids coformer

    Science.gov (United States)

    Singh, Neetu; Singh, Udai P.; Nikhil, Kumar; Roy, Partha; Singh, Hariji

    2017-10-01

    The reactions of natural and unnatural nucleobases (cytosine (Cyt), adenine (Ade), 5-aminouracil (AU) and caffeine (Caff)) with sulfonic acids coformer (1,5-naphthalenedisulfonic acid, NDSA; 5-sulfosalicylic acid, SSA) resulted in the formation of salts viz. [NDSA.Cyt] (1), [NDSA.Ade] (2), [NDSA.AU] (3), [NDSA.Caff] (4), [SSA.Cyt] (5), [SSA.Ade] (6), [SSA.AU] (7), and [SSA.Caff] (8). The structural analysis revealed that salts 1, 4, 6 and 7 have intermolecular interactions between adjacent nucleobases which form two different homodimer shown in R22 (8) motif and assembled via complementary Nsbnd H⋯O and Nsbnd H⋯N interactions. However, in all other salts an intermediate supramolecular synthon pattern was observed between nucleobases and sulfonic acids. The lattice energy was also calculated by DFT to investigate whether salts were thermodynamically more stable than its coformer. The same was further confirmed by differential scanning calorimetry-thermogravimetric (DSC-TG) analysis. The anticancer activity study of individual nucleobases and their NDSA salts were also performed on human breast (MCF-7) and lung (A 549) cancer cell. The salts formation of nucleobases with sulfonic acids improved their solubility, thereby demonstrating up to 8-fold increase in solubility of nucleobases.

  18. A first-principles study of half-metallic ferromagnetism in binary alkaline-earth nitrides with rock-salt structure

    International Nuclear Information System (INIS)

    Gao, G.Y.; Yao, K.L.; Liu, Z.L.; Zhang, J.; Min, Y.; Fan, S.W.

    2008-01-01

    In this Letter, using the first-principles full-potential linearized augmented plane-wave (FP-LAPW) method, we extend the electronic structure and magnetism studies on zinc-blende structure of II-V compounds MX (M=Ca,Sr,Ba; X=N,P,As) [M. Sieberer, J. Redinger, S. Khmelevskyi, P. Mohn, Phys. Rev. B 73 (2006) 024404] to the rock-salt structure. It is found that, in the nine compounds, only alkaline-earth nitrides CaN, SrN and BaN exhibit ferromagnetic half-metallic character with a magnetic moment of 1.00μ B per formula unit. Furthermore, compared with the zinc-blende structure of CaN, SrN and BaN, the rock-salt structure has lower energy, which makes them more promising candidates of possible growth of half-metallic films on suitable substrates

  19. Salt bridges: geometrically specific, designable interactions.

    Science.gov (United States)

    Donald, Jason E; Kulp, Daniel W; DeGrado, William F

    2011-03-01

    Salt bridges occur frequently in proteins, providing conformational specificity and contributing to molecular recognition and catalysis. We present a comprehensive analysis of these interactions in protein structures by surveying a large database of protein structures. Salt bridges between Asp or Glu and His, Arg, or Lys display extremely well-defined geometric preferences. Several previously observed preferences are confirmed, and others that were previously unrecognized are discovered. Salt bridges are explored for their preferences for different separations in sequence and in space, geometric preferences within proteins and at protein-protein interfaces, co-operativity in networked salt bridges, inclusion within metal-binding sites, preference for acidic electrons, apparent conformational side chain entropy reduction on formation, and degree of burial. Salt bridges occur far more frequently between residues at close than distant sequence separations, but, at close distances, there remain strong preferences for salt bridges at specific separations. Specific types of complex salt bridges, involving three or more members, are also discovered. As we observe a strong relationship between the propensity to form a salt bridge and the placement of salt-bridging residues in protein sequences, we discuss the role that salt bridges might play in kinetically influencing protein folding and thermodynamically stabilizing the native conformation. We also develop a quantitative method to select appropriate crystal structure resolution and B-factor cutoffs. Detailed knowledge of these geometric and sequence dependences should aid de novo design and prediction algorithms. Copyright © 2010 Wiley-Liss, Inc.

  20. Sequestration of CO2 in salt caverns

    International Nuclear Information System (INIS)

    Dusseault, M.B.; Rothenburg, L.; Bachu, S.

    2002-01-01

    The greenhouse effect is thought to be greatly affected by anthropogenic and naturally generated gases, such as carbon dioxide. The reduction of greenhouse gas emissions in the atmosphere could be effected through the permanent storage of carbon dioxide in dissolved salt caverns. A large number of suitable salt deposits are located in Alberta, especially the Lotsberg Salt of east-central Alberta. A major advantage of this deposit is its proximity to present and future point sources of carbon dioxide associated with fossil fuel development projects. Using the perspective of the long term fate of the stored carbon dioxide, the authors presented the characteristics of the Lotsberg Salt and the overlying strata. A high level of security against leakage and migration of the gas back to the biosphere is ensured by several features discussed in the paper. The authors propose a procedure that would be applicable for the creation, testing, and filling of a salt cavern. Achieving a long term prediction of the behavior of the cavern during slow closure, coupled to the pressure and volume behavior of the gas within the cavern represents the critical factor. The authors came up with an acceptable prediction by using a semi-analytical model. The use of salt caverns for the permanent sequestration of carbon dioxide has not yet faced technical obstacles that would prevent it. The authors argue that sequestration of carbon dioxide in salt caverns represents an environmentally acceptable option in Alberta. 11 refs., 3 figs

  1. Multisource least-squares reverse-time migration with structure-oriented filtering

    Science.gov (United States)

    Fan, Jing-Wen; Li, Zhen-Chun; Zhang, Kai; Zhang, Min; Liu, Xue-Tong

    2016-09-01

    The technology of simultaneous-source acquisition of seismic data excited by several sources can significantly improve the data collection efficiency. However, direct imaging of simultaneous-source data or blended data may introduce crosstalk noise and affect the imaging quality. To address this problem, we introduce a structure-oriented filtering operator as preconditioner into the multisource least-squares reverse-time migration (LSRTM). The structure-oriented filtering operator is a nonstationary filter along structural trends that suppresses crosstalk noise while maintaining structural information. The proposed method uses the conjugate-gradient method to minimize the mismatch between predicted and observed data, while effectively attenuating the interference noise caused by exciting several sources simultaneously. Numerical experiments using synthetic data suggest that the proposed method can suppress the crosstalk noise and produce highly accurate images.

  2. Hydrogen impurity in SrTiO{sub 3}: structure, electronic properties and migration

    Energy Technology Data Exchange (ETDEWEB)

    Villamagua, Luis [Grupo de Fisica de Cristales, Escuela de Electronica y Telecomunicaciones, Universidad Tecnica Particular de Loja, Apartado 11-01-608, Loja (Ecuador); Barreto, Rafael [Facultad de IngenierIa Civil, Escuela Politecnica Nacional, Apartado 14-01-2759, Quito (Ecuador); Procel, Luis Miguel [Departamento de Quimica, Colegio Politecnico, Universidad San Francisco de Quito, Apartado 17-12-841, Quito (Ecuador); Stashans, Arvids [Grupo de Fisica de Cristales, Escuela de Electronica y Telecomunicaciones, Universidad Tecnica Particular de Loja, Apartado 11-01-608, Loja (Ecuador)

    2007-03-15

    The present paper reports a computational investigation of the geometry and electronic structure as well as the migration of a hydrogen impurity in the cubic SrTiO{sub 3} crystal. The study is done using an approach based on the Hartree-Fock theory and developed for periodic systems. It is found that the H impurity forms the so-called OH group at the equilibrium. Analysis of electron density within the defective region implies the enhancement in covalent chemical bonding. A possible defect migration has been also investigated.

  3. Formation of an Anti-Core–Shell Structure in Layered Oxide Cathodes for Li-Ion Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hanlei [Materials; amp, Department; NorthEast; Omenya, Fredrick [NorthEast; Whittingham, M. Stanley [NorthEast; Wang, Chongmin [Environmental; Zhou, Guangwen [Materials; amp, Department; NorthEast

    2017-10-20

    The layered → rock-salt phase transformation in the layered dioxide cathodes for Li-ion batteries is believed to result in a “core-shell” structure of the primary particles, in which the core region maintains as the layered phase while the surface region undergoes the phase transformation to the rock-salt phase. Using transmission electron microscopy, here we demonstrate the formation of an “anti-core-shell” structure in cycled primary particles with a formula of LiNi0.80Co0.15Al0.05O2, in which the surface and subsurface regions remain as the layered structure while the rock-salt phase forms as domains in the bulk with a thin layer of the spinel phase between the rock-salt core and the skin of the layered phase. Formation of this anti-core-shell structure is attributed to the oxygen loss at the surface that drives the migration of oxygen from the bulk to the surface, thereby resulting in localized areas of significantly reduced oxygen levels in the bulk of the particle, which subsequently undergoes the phase transformation to the rock-salt domains. The formation of the anti-core-shell rock-salt domains is responsible for the reduced capacity, discharge voltage and ionic conductivity in cycled cathode.

  4. Origin of salt giants in abyssal serpentinite systems

    Science.gov (United States)

    Scribano, Vittorio; Carbone, Serafina; Manuella, Fabio C.; Hovland, Martin; Rueslåtten, Håkon; Johnsen, Hans-K.

    2017-10-01

    Worldwide marine salt deposits ranging over the entire geological record are generally considered climate-related evaporites, derived from the precipitation of salts (mainly chlorides and sulfates) from saturated solutions driven by solar evaporation of seawater. This explanation may be realistic for a salt thickness ≤100 m, being therefore inadequate for thicker (>1 km) deposits. Moreover, sub-seafloor salt deposits in deep marine basins are difficult to reconcile with a surface evaporation model. Marine geology reports on abyssal serpentinite systems provide an alternative explanation for some salt deposits. Seawater-driven serpentinization consumes water and increases the salinity of the associated aqueous brines. Brines can be trapped in fractures and cavities in serpentinites and the surrounding `country' rocks. Successive thermal dehydration of buried serpentinites can mobilize and accumulate the brines, forming highly saline hydrothermal solutions. These can migrate upwards and erupt onto the seafloor as saline geysers, which may form salt-saturated water pools, as are currently observed in numerous deeps in the Red Sea and elsewhere. The drainage of deep-seated saline brines to seafloor may be a long-lasting, effective process, mainly occurring in areas characterized by strong tectonic stresses and/or igneous intrusions. Alternatively, brines could be slowly expelled from fractured serpentinites by buoyancy gradients and, hence, separated salts/brines could intrude vertically into surrounding rocks, forming salt diapirs. Serpentinization is an ubiquitous, exothermic, long-lasting process which can modify large volumes of oceanic lithosphere over geological times. Therefore, buried salt deposits in many areas of the world can be reasonably related to serpentinites.

  5. Corrosion of candidate iron-base waste package structural barrier materials in moist salt environments

    International Nuclear Information System (INIS)

    Westerman, R.E.; Pitman, S.G.

    1984-11-01

    Mild steels are considered to be strong candidates for waste package structural barrier (e.g., overpack) applications in salt repositories. Corrosion rates of these materials determined in autoclave tests utilizing a simulated intrusion brine based on Permian Basin core samples are low, generally <25 μm (1 mil) per year. When the steels are exposed to moist salts containing simulated inclusion brines, the corrosion rates are found to increase significantly. The magnesium in the inclusion brine component of the environment is believed to be responsible for the increased corrosion rates. 1 reference, 4 figures, 2 tables

  6. Structural and theoretical investigations of 3,4,5-triamino-1,2,4-triazolium salts

    Energy Technology Data Exchange (ETDEWEB)

    Drake, Gregory W. [Propulsion Research Laboratory XD22, Marshall Space Flight Center, AL 35812 (United States); Hawkins, Tommy W.; Hall, Leslie A.; Boatz, Jerry A.; Brand, Adam J. [AFRL/PRSP Space and Missile Propulsion Division, 10 East Saturn Boulevard, Edwards AFB, CA 93524 (United States)

    2005-10-01

    Reactions using the high nitrogen heterocycle 3,4,5-triamino-1,2,4-triazole (guanazine) with strong acids (HNO{sub 3}, HClO{sub 4}, and ''HN(NO{sub 2}){sub 2}'') resulted in a family of highly stable salts. All of the salts were characterized using spectroscopic as well as single crystal X-ray diffraction studies. The X-ray structures were compared to that obtained from theoretical calculations (MP2/6-311+G(d, p) level). Initial safety testing (impact, friction) was carried out on all of the new materials. (Abstract Copyright [2005], Wiley Periodicals, Inc.)

  7. Microbiological investigation of soil samples of the caprock above the Gorleben salt dome

    International Nuclear Information System (INIS)

    Kutzner, H.J.; Sonnen, H.; Bachmann, F.

    1993-01-01

    Microorganisms constitute an essential part of the soil structure. Through their activities a large number of processes in the soil are caused: decomposition (mineralization) and conversion (humate formation) of organic substances; formation of biomass (reproduction); oxidation and reduction of various elements or compounds, and thus generation of a geomicrobiological cycle of nitrogen, sulphur, iron, manganese and other elements; and, at the same time, by means of oxidation/reduction processes they cause modifications of the solubility of metals (precipitation or mobility increase). Therefore, an influence exerted by microorganisms, as an integral part of the caprock, on radionuclide migration cannot be excluded. The investigations performed served to look into the question to which extent microorganisms occur in the profile of the caprock above the Gorleben salt dome; which geomicrobiological activities are to be expected there due to their physiological properties, and whether their influence on radionuclide migration seems to be realistic. (orig./DG) [de

  8. Mechanical stratification of autochthonous salt: Implications from basin-scale numerical models of rifted margin salt tectonics

    Science.gov (United States)

    Ings, Steven; Albertz, Markus

    2014-05-01

    Deformation of salt and sediments owing to the flow of weak evaporites is a common phenomenon in sedimentary basins worldwide, and the resulting structures and thermal regimes have a significant impact on hydrocarbon exploration. Evaporite sequences ('salt') of significant thickness (e.g., >1km) are typically deposited in many cycles of seawater inundation and evaporation in restricted basins resulting in layered autochthonous evaporite packages. However, analogue and numerical models of salt tectonics typically treat salt as a homogeneous viscous material, often with properties of halite, the weakest evaporite. In this study, we present results of two-dimensional plane-strain numerical experiments designed to illustrate the effects of variable evaporite viscosity and embedded frictional-plastic ('brittle') sediment layers on the style of salt flow and associated deformation of the sedimentary overburden. Evaporite viscosity is a first-order control on salt flow rate and the style of overburden deformation. Near-complete evacuation of low-viscosity salt occurs beneath expulsion basins, whereas significant salt is trapped when viscosity is high. Embedded frictional-plastic sediment layers (with finite yield strength) partition salt flow and develop transient contractional structures (folds, thrust faults, and folded faults) in a seaward salt-squeeze flow regime. Multiple internal sediment layers reduce the overall seaward salt flow during sediment aggradation, leaving more salt behind to be re-mobilized during subsequent progradation. This produces more seaward extensive allochthonous salt sheets. If there is a density difference between the embedded layers and the surrounding salt, then the embedded layers 'fractionate' during deformation and either float to the surface or sink to the bottom (depending on density), creating a thick zone of pure halite. Such a process of 'buoyancy fractionation' may partially explain the apparent paradox of layered salt in

  9. Evaluation of mapping results of the textural features of the Gorleben-Bank within the Gorleben salt dome, Germany

    International Nuclear Information System (INIS)

    Kuehnlenz, Tatjana; Hammer, Joerg; Mingerzahn, Gerhard; Sassnowski, Marco; Kutowski, Joachim

    2014-01-01

    The ''Gorleben-Bank'' (z3OSM) is a marker horizon within the ''Orangesalz'' (z3OS) of the ''Leine-Folge'' (z3) in the Gorleben salt dome. In some areas the Gorleben-Bank and/or the surrounding rocks contain brines and gases. The occurrence of brines and gases could be hazardous for a repository. Therefore it is important to analyse the lithological and structural characteristics of the Gorleben-Bank. As part of the project ''Continuation of exploration of the Gorleben salt dome'', all exposures of the Gorleben-Bank in drifts, shafts and exploration boreholes were documented and incorporated within a database. Analogous to Baeuerle (2000), seven zones were identified within the Gorleben-Bank from bottom to top. The total thickness of the Gorleben-Bank and the thickness of the zones relevant for migration and storage of brines and gases were considered in this paper. The fissures and the zone of secondary mineralisation of the Gorleben-Bank (Zone IV), generated during the halotectonic processes, as well as brines in the Gorleben-Bank and its surrounding rocks, were analysed regarding their genesis and spatial distribution in the salt dome. These analyses allow conclusions about deformation behaviour of the Gorleben-Bank and its potential for storage of solutions and migration capability for brines and gases. With the program GEOravis some database contents e.g. the thickness of the Gorleben-Bank or location of brine adits were visualised in 3D space for better spatial understanding.

  10. The structure of salt bridges between Arg(+) and Glu(-) in peptides investigated with 2D-IR spectroscopy: Evidence for two distinct hydrogen-bond geometries.

    Science.gov (United States)

    Huerta-Viga, Adriana; Amirjalayer, Saeed; Domingos, Sérgio R; Meuzelaar, Heleen; Rupenyan, Alisa; Woutersen, Sander

    2015-06-07

    Salt bridges play an important role in protein folding and in supramolecular chemistry, but they are difficult to detect and characterize in solution. Here, we investigate salt bridges between glutamate (Glu(-)) and arginine (Arg(+)) using two-dimensional infrared (2D-IR) spectroscopy. The 2D-IR spectrum of a salt-bridged dimer shows cross peaks between the vibrational modes of Glu(-) and Arg(+), which provide a sensitive structural probe of Glu(-)⋯Arg(+) salt bridges. We use this probe to investigate a β-turn locked by a salt bridge, an α-helical peptide whose structure is stabilized by salt bridges, and a coiled coil that is stabilized by intra- and intermolecular salt bridges. We detect a bidentate salt bridge in the β-turn, a monodentate one in the α-helical peptide, and both salt-bridge geometries in the coiled coil. To our knowledge, this is the first time 2D-IR has been used to probe tertiary side chain interactions in peptides, and our results show that 2D-IR spectroscopy is a powerful method for investigating salt bridges in solution.

  11. Spectroscopic and structural studies on some divalent metal salt of p-aminobenzoic acid (ABA(MG)) tetracyanonickelate complexes

    International Nuclear Information System (INIS)

    Atalay, Y.

    2004-01-01

    Infrared spectra of MLNi (CN) 4 [ M=Mn, Fe, Co, Ni, Zn or Cd and LDivalent metal salt of p- Aminobenzoic Acid or ABA (Mg) ] are reported. Their structure consists of polymeric layers of [M-Ni(CN) 4 ] α with the divalent metal salt of p-aminobenzoic acid [ABA(Mg)] molecules bound directly to the metal (M). These spectra were comparewith powder the Xray diffraction pattern of complexes. It is show that proposed structures for these complexes derived from Mattson 1000 FTIR spectra are consistent with the X-ray powder diffraction measurements and elemental analysis result

  12. Separation and Fixation of Toxic Components in Salt Brines Using a Water-Based Process

    International Nuclear Information System (INIS)

    Franks, Carrie J.; Quach, Anh P.; Birnie, Dunbar P.; Ela, Wendell P.; Saez, Avelino E.; Zelinski, Brian J.; Smith, Harry D.; Smith, Gary Lynn L.

    2004-01-01

    Efforts to implement new water quality standards, increase water reuse and reclamation, and minimize the cost of waste storage motivate the development of new processes for stabilizing waste water residuals that minimize waste volume, water content and the long-term environmental risk from related by products. This work explores the use of an aqueous-based emulsion process to create an epoxy/rubber matrix for separating and encapsulating waste components from salt laden, arsenic contaminated, amorphous iron hydrate sludges. Such sludges are generated from conventional water purification precipitation/adsorption processes, used to convert aqueous brine streams to semi-solid waste streams, such as ion exchange/membrane separation, and from other precipitative heavy metal removal operations. In this study, epoxy and polystyrene butadiene (PSB) rubber emulsions are mixed together and then combined with a surrogate sludge. The surrogate sludge consists of amorphous iron hydrate with 1 part arsenic fixed to the surface of the hydrate per 10 parts iron mixed with sodium nitrate and chloride salts and water. The resulting emulsion is cured and dried at 80 C to remove water. Microstructure characterization by electron microscopy confirms that the epoxy/PSB matrix surrounds and encapsulates the arsenic laden amorphous iron hydrate phase while allowing the salt to migrate to internal and external surfaces of the sample. Salt extraction studies indicate that the porous nature of the resulting matrix promotes the separation and removal of as much as 90% of the original salt content in only one hours time. Long term leaching studies based on the use of the infinite slab diffusion model reveal no evidence of iron migration or, by inference, arsenic migration, and demonstrate that the diffusion coefficients of the unextracted salt yield leachability indices within regulations for non-hazardous landfill disposal. Because salt is the most mobile species, it is inferred that arsenic

  13. Japanese migration in contemporary Japan: economic segmentation and interprefectural migration.

    Science.gov (United States)

    Fukurai, H

    1991-01-01

    This paper examines the economic segmentation model in explaining 1985-86 Japanese interregional migration. The analysis takes advantage of statistical graphic techniques to illustrate the following substantive issues of interregional migration: (1) to examine whether economic segmentation significantly influences Japanese regional migration and (2) to explain socioeconomic characteristics of prefectures for both in- and out-migration. Analytic techniques include a latent structural equation (LISREL) methodology and statistical residual mapping. The residual dispersion patterns, for instance, suggest the extent to which socioeconomic and geopolitical variables explain migration differences by showing unique clusters of unexplained residuals. The analysis further points out that extraneous factors such as high residential land values, significant commuting populations, and regional-specific cultures and traditions need to be incorporated in the economic segmentation model in order to assess the extent of the model's reliability in explaining the pattern of interprefectural migration.

  14. Migration decisions, agrarian structure, and gender: the case of Ecuador.

    Science.gov (United States)

    Bravo-ureta, B E; Quiroga, R E; Brea, J A

    1996-07-01

    This article briefly reviews the literature on migration in Latin America and examines migration decision making in Ecuador. Aggregate data are obtained from the 1974 census of agriculture and population for cantones. Individual level data are obtained from the 1982 census of population. Migration refers to all census persons who recorded differences in their present and previous place of residence during 1974-82. Migration is modeled as dependent upon gender, age, education, marital status, income at origin and at destination, and population pressure or agrarian reform. Logistic model findings indicate that migration decisions are influenced by individual characteristics of migrants and contextual variables. Migration varied by gender. The results confirm Todaro's hypothesis that the probability of migrating is related to income differences between place of destination and origin, but only for males. Findings suggest that females migrate for primary reasons other than economic ones. The probability of migration was greater with increased levels of education. The decision to migrate was affected by quality of life differences, such as literacy rates and levels of urbanization. The probability of migration was reduced by the effects of land reform. Population pressure had a significant effect in increasing migration. The effects of land reform differ from findings in Mexico by William E. Cole and Richard D. Sanders. Land reforms were initiated in 1964 in Ecuador, but by 1974 there was still considerable inequality in land distribution and increased population pressure. Traditional haciendas were modernized, and peasants increased their dependency on non-farm income.

  15. Least-squares migration of multisource data with a deblurring filter

    KAUST Repository

    Dai, Wei; Wang, Xin; Schuster, Gerard T.

    2011-01-01

    Least-squares migration (LSM) has been shown to be able to produce high-quality migration images, but its computational cost is considered to be too high for practical imaging. We have developed a multisource least-squares migration algorithm (MLSM) to increase the computational efficiency by using the blended sources processing technique. To expedite convergence, a multisource deblurring filter is used as a preconditioner to reduce the data residual. This MLSM algorithm is applicable with Kirchhoff migration, wave-equation migration, or reverse time migration, and the gain in computational efficiency depends on the choice of migration method. Numerical results with Kirchhoff LSM on the 2D SEG/EAGE salt model show that an accurate image is obtained by migrating a supergather of 320 phase-encoded shots. When the encoding functions are the same for every iteration, the input/output cost of MLSM is reduced by 320 times. Empirical results show that the crosstalk noise introduced by blended sources is more effectively reduced when the encoding functions are changed at every iteration. The analysis of signal-to-noise ratio (S/N) suggests that not too many iterations are needed to enhance the S/N to an acceptable level. Therefore, when implemented with wave-equation migration or reverse time migration methods, the MLSM algorithm can be more efficient than the conventional migration method. © 2011 Society of Exploration Geophysicists.

  16. Least-squares migration of multisource data with a deblurring filter

    KAUST Repository

    Dai, Wei

    2011-09-01

    Least-squares migration (LSM) has been shown to be able to produce high-quality migration images, but its computational cost is considered to be too high for practical imaging. We have developed a multisource least-squares migration algorithm (MLSM) to increase the computational efficiency by using the blended sources processing technique. To expedite convergence, a multisource deblurring filter is used as a preconditioner to reduce the data residual. This MLSM algorithm is applicable with Kirchhoff migration, wave-equation migration, or reverse time migration, and the gain in computational efficiency depends on the choice of migration method. Numerical results with Kirchhoff LSM on the 2D SEG/EAGE salt model show that an accurate image is obtained by migrating a supergather of 320 phase-encoded shots. When the encoding functions are the same for every iteration, the input/output cost of MLSM is reduced by 320 times. Empirical results show that the crosstalk noise introduced by blended sources is more effectively reduced when the encoding functions are changed at every iteration. The analysis of signal-to-noise ratio (S/N) suggests that not too many iterations are needed to enhance the S/N to an acceptable level. Therefore, when implemented with wave-equation migration or reverse time migration methods, the MLSM algorithm can be more efficient than the conventional migration method. © 2011 Society of Exploration Geophysicists.

  17. Nitrogen-rich salts of 5,5‧-bistetrazole-1,1‧-diolate: Syntheses, structures and properties

    Science.gov (United States)

    Yang, Ting; Zhang, Jian-Guo; Zhang, Zhi-Bin; Gozin, Michael

    2018-03-01

    A series of new nitrogen-rich energetic salts containing 1H,1‧H-[5,5‧-bitetrazole]-1,1‧-diol (BTO) anion and ethane-1,2-diaminium (1), 1-amino-1H-1,2,3-triazol-3-ium (2), 4-amino-4H-1,2,4-triazol-1-ium (3) and 4,5-diamino-4H-1,2,4-triazol-1-ium (4) cations were synthesized by direct salt formation or by metathesis strategy. The structures of energetic salts 1-4 were comprehensively characterized by elemental analysis, mass spectrometry, IR and NMR spectroscopies and by X-ray crystallography. DSC and TGA methods were used to study thermal properties of these salts. Additionally, the non-isothermal kinetic parameters and thermodynamic parameters were calculated by utilizing the Kissinger's and Ozawa-Doyle's methods. The enthalpies of formation for all target compounds in this study were calculated, and their sensitivity to mechanical impact and friction was tested according to BAM guidelines. We found these new energetic salts exhibit good thermal stability and have typical decomposition temperatures above 230 °C, except for the salt 2. All our salts have highly-positive enthalpies of formation (311.1-473.6 kJ mol-1) and are insensitive to impact and friction stimuli (>40 J, 120 N). With a high nitrogen-rich content, high enthalpy of formation, good thermostability and very low sensitivity to impact, some of these new salts may have a potential for application in the field of environmentally friendly insensitive energetic materials.

  18. Multisource least-squares migration of marine streamer and land data with frequency-division encoding

    KAUST Repository

    Huang, Yunsong; Schuster, Gerard T.

    2012-01-01

    Multisource migration of phase-encoded supergathers has shown great promise in reducing the computational cost of conventional migration. The accompanying crosstalk noise, in addition to the migration footprint, can be reduced by least-squares inversion. But the application of this approach to marine streamer data is hampered by the mismatch between the limited number of live traces/shot recorded in the field and the pervasive number of traces generated by the finite-difference modelling method. This leads to a strong mismatch in the misfit function and results in strong artefacts (crosstalk) in the multisource least-squares migration image. To eliminate this noise, we present a frequency-division multiplexing (FDM) strategy with iterative least-squares migration (ILSM) of supergathers. The key idea is, at each ILSM iteration, to assign a unique frequency band to each shot gather. In this case there is no overlap in the crosstalk spectrum of each migrated shot gather m(x, ω i), so the spectral crosstalk product m(x, ω i)m(x, ω j) =δ i, j is zero, unless i=j. Our results in applying this method to 2D marine data for a SEG/EAGE salt model show better resolved images than standard migration computed at about 1/10 th of the cost. Similar results are achieved after applying this method to synthetic data for a 3D SEG/EAGE salt model, except the acquisition geometry is similar to that of a marine OBS survey. Here, the speedup of this method over conventional migration is more than 10. We conclude that multisource migration for a marine geometry can be successfully achieved by a frequency-division encoding strategy, as long as crosstalk-prone sources are segregated in their spectral content. This is both the strength and the potential limitation of this method. © 2012 European Association of Geoscientists & Engineers.

  19. Multisource least-squares migration of marine streamer and land data with frequency-division encoding

    KAUST Repository

    Huang, Yunsong

    2012-05-22

    Multisource migration of phase-encoded supergathers has shown great promise in reducing the computational cost of conventional migration. The accompanying crosstalk noise, in addition to the migration footprint, can be reduced by least-squares inversion. But the application of this approach to marine streamer data is hampered by the mismatch between the limited number of live traces/shot recorded in the field and the pervasive number of traces generated by the finite-difference modelling method. This leads to a strong mismatch in the misfit function and results in strong artefacts (crosstalk) in the multisource least-squares migration image. To eliminate this noise, we present a frequency-division multiplexing (FDM) strategy with iterative least-squares migration (ILSM) of supergathers. The key idea is, at each ILSM iteration, to assign a unique frequency band to each shot gather. In this case there is no overlap in the crosstalk spectrum of each migrated shot gather m(x, ω i), so the spectral crosstalk product m(x, ω i)m(x, ω j) =δ i, j is zero, unless i=j. Our results in applying this method to 2D marine data for a SEG/EAGE salt model show better resolved images than standard migration computed at about 1/10 th of the cost. Similar results are achieved after applying this method to synthetic data for a 3D SEG/EAGE salt model, except the acquisition geometry is similar to that of a marine OBS survey. Here, the speedup of this method over conventional migration is more than 10. We conclude that multisource migration for a marine geometry can be successfully achieved by a frequency-division encoding strategy, as long as crosstalk-prone sources are segregated in their spectral content. This is both the strength and the potential limitation of this method. © 2012 European Association of Geoscientists & Engineers.

  20. Salt tectonics in Santos Basin, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Quirk, David G.; Nielsen, Malene; Raven, Madeleine [Maersk Oil and Gas, Copenhagen (Denmark); Menezes, Paulo [Maersk Oil and Gas, Rio de Janeiro, RJ (Brazil)

    2008-07-01

    From Albian to end Cretaceous times, the inboard part of the Santos Basin in Brazil was affected by extension as salt flowed basinwards under the effect of gravity. Salt rollers, flip-flop salt diapirs and the famous Albian Gap were all formed by this process. Outboard of these extensional structures, contraction was taken up in a wide zone of thickened salt where salt collected. The overburden was carried on top of the salt as it flowed down-dip, with up to 40 km of translation recorded in Albian strata. (author)

  1. Nuclear waste repository simulation experiments, Asse Salt Mine, Federal Republic of Germany. Annual report, 1983

    International Nuclear Information System (INIS)

    Rothfuchs, T.; Luebker, D.; Coyle, A.; Kalia, H.

    1984-10-01

    This is the First Annual report (1983) which describes experiments simulating a nuclear waste respository at the 800-meter level of the Asse Salt Mine in the Federal Republic of Germany. The report describes the test equipment, the Asse Salt Mine, the pretest properties of the salt in the test gallery, and the mine proper. Also included are test data for the first six months of operations on brine migration rates, room closure rates, extensometer readings, stress measurements, and thermal mechanical behavior of the salt. The duration of the experiments will be two years, ending in December 1985. 3 references, 34 figures, 13 tables

  2. Thermal responses in underground experiments in a dome salt formation

    International Nuclear Information System (INIS)

    Llewellyn, G.H.

    1977-01-01

    To provide design information for a radwaste repository in dome salt, in-situ experiments with nonradioactive heat sources are planned. Three such experiments using electrical heat sources are scheduled to be carried out in a salt dome. The purpose of these experiments is to acquire rock mechanics data to ascertain the structural deformation due to the thermal load imposed, to study brine migration and corrosion, and to provide thermal data. A data acquisition system is provided with these experiments to monitor temperatues, heat fluxes, stresses, and ground displacement. A thermal analysis was made on models of each of these experiments. The objective of the analysis is to verify the capability of making accurate transient temperature predictions by the use of computer modeling techniques. Another purpose is to measure in-situ thermal conductivity and compare the results with measurements taken from core samples. The HEATING5 computer program was used to predict transient temperatures around the experiments for periods up to 2 years using two-dimensional and three-dimensional heat transfer models. The results of analysis are presented with the associated boundary conditions used in the individual models

  3. The utility of petroleum seismic exploration data in delineating structural features within salt anticlines

    Science.gov (United States)

    Stockton, S.L.; Balch, Alfred H.

    1978-01-01

    The Salt Valley anticline, in the Paradox Basin of southeastern Utah, is under investigation for use as a location for storage of solid nuclear waste. Delineation of thin, nonsalt interbeds within the upper reaches of the salt body is extremely important because the nature and character of any such fluid- or gas-saturated horizons would be critical to the mode of emplacement of wastes into the structure. Analysis of 50 km of conventional seismic-reflection data, in the vicinity of the anticline, indicates that mapping of thin beds at shallow depths may well be possible using a specially designed adaptation of state-of-the-art seismic oil-exploration procedures. Computer ray-trace modeling of thin beds in salt reveals that the frequency and spatial resolution required to map the details of interbeds at shallow depths (less than 750 m) may be on the order of 500 Hz, with surface-spread lengths of less than 350 m. Consideration should be given to the burial of sources and receivers in order to attenuate surface noise and to record the desired high frequencies. Correlation of the seismic-reflection data with available well data and surface geology reveals the complex, structurally initiated diapir, whose upward flow was maintained by rapid contemporaneous deposition of continental clastic sediments on its flanks. Severe collapse faulting near the crests of these structures has distorted the seismic response. Evidence exists, however, that intrasalt thin beds of anhydrite, dolomite, and black shale are mappable on seismic record sections either as short, discontinuous reflected events or as amplitude anomalies that result from focusing of the reflected seismic energy by the thin beds; computer modeling of the folded interbeds confirms both of these as possible causes of seismic response from within the salt diapir. Prediction of the seismic signatures of the interbeds can be made from computer-model studies. Petroleum seismic-reflection data are unsatisfactory for

  4. Structural evidence for solvent-stabilisation by aspartic acid as a mechanism for halophilic protein stability in high salt concentrations.

    Science.gov (United States)

    Lenton, Samuel; Walsh, Danielle L; Rhys, Natasha H; Soper, Alan K; Dougan, Lorna

    2016-07-21

    Halophilic organisms have adapted to survive in high salt environments, where mesophilic organisms would perish. One of the biggest challenges faced by halophilic proteins is the ability to maintain both the structure and function at molar concentrations of salt. A distinct adaptation of halophilic proteins, compared to mesophilic homologues, is the abundance of aspartic acid on the protein surface. Mutagenesis and crystallographic studies of halophilic proteins suggest an important role for solvent interactions with the surface aspartic acid residues. This interaction, between the regions of the acidic protein surface and the solvent, is thought to maintain a hydration layer around the protein at molar salt concentrations thereby allowing halophilic proteins to retain their functional state. Here we present neutron diffraction data of the monomeric zwitterionic form of aspartic acid solutions at physiological pH in 0.25 M and 2.5 M concentration of potassium chloride, to mimic mesophilic and halophilic-like environmental conditions. We have used isotopic substitution in combination with empirical potential structure refinement to extract atomic-scale information from the data. Our study provides structural insights that support the hypothesis that carboxyl groups on acidic residues bind water more tightly under high salt conditions, in support of the residue-ion interaction model of halophilic protein stabilisation. Furthermore our data show that in the presence of high salt the self-association between the zwitterionic form of aspartic acid molecules is reduced, suggesting a possible mechanism through which protein aggregation is prevented.

  5. Interfacial Mechanism in Lithium-Sulfur Batteries: How Salts Mediate the Structure Evolution and Dynamics.

    Science.gov (United States)

    Lang, Shuang-Yan; Xiao, Rui-Juan; Gu, Lin; Guo, Yu-Guo; Wen, Rui; Wan, Li-Jun

    2018-06-08

    Lithium-sulfur batteries possess favorable potential for energy-storage applications due to their high specific capacity and the low cost of sulfur. Intensive understanding of the interfacial mechanism, especially the polysulfide formation and transformation under complex electrochemical environment, is crucial for the build-up of advanced batteries. Here we report the direct visualization of interfacial evolution and dynamic transformation of the sulfides mediated by the lithium salts via real-time atomic force microscopy monitoring inside a working battery. The observations indicate that the lithium salts influence the structures and processes of sulfide deposition/decomposition during discharge/charge. Moreover, the distinct ion interaction and diffusion in electrolytes manipulate the interfacial reactions determining the kinetics of the sulfide transformation. Our findings provide deep insights into surface dynamics of lithium-sulfur reactions revealing the salt-mediated mechanisms at nanoscale, which contribute to the profound understanding of the interfacial processes for the optimized design of lithium-sulfur batteries.

  6. Migration of northern yellowstone elk: Implications of spatial structuring

    Science.gov (United States)

    White, P.J.; Proffitt, K.M.; Mech, L.D.; Evans, S.B.; Cunningham, J.A.; Hamlin, K.L.

    2010-01-01

    Migration can enhance survival and recruitment of mammals by increasing access to higher-quality forage or reducing predation risk, or both. We used telemetry locations collected from 140 adult female elk during 20002003 and 20072008 to identify factors influencing the migration of northern Yellowstone elk. Elk wintered in 2 semidistinct herd segments and migrated 10140 km to at least 12 summer areas in Yellowstone National Park (YNP) and nearby areas of Montana. Spring migrations were delayed after winters with increased snow pack, with earlier migration in years with earlier vegetation green-up. Elk wintering at lower elevations outside YNP migrated an average of 13 days earlier than elk at higher elevations. The timing of autumn migrations varied annually, but elk left their summer ranges at about the same time regardless of elevation, wolf numbers, or distance to their wintering areas. Elk monitored for multiple years typically returned to the same summer (96 fidelity, n 52) and winter (61 fidelity, n 41) ranges. Elk that wintered at lower elevations in or near the northwestern portion of the park tended to summer in the western part of YNP (56), and elk that wintered at higher elevations spent summer primarily in the eastern and northern parts of the park (82). Elk did not grossly modify their migration timing, routes, or use areas after wolf restoration. Elk mortality was low during summer and migration (8 of 225 elk-summers). However, spatial segregation and differential mortality and recruitment between herd segments on the northern winter range apparently contributed to a higher proportion of the elk population wintering outside the northwestern portion of YNP and summering in the western portion of the park. This change could shift wolf spatial dynamics more outside YNP and increase the risk of transmission of brucellosis from elk to cattle north of the park. ?? 2010 American Society of Mammalogists.

  7. Effect of water in salt repositories. Final report

    International Nuclear Information System (INIS)

    Baes, C.F. Jr.; Gilpatrick, L.O.; Kitts, F.G.; Bronstein, H.R.; Shor, A.J.

    1983-09-01

    Additional results confirm that during most of the consolidation of polycrystalline salt in brine, the previously proposed rate expression applies. The final consolidation, however, proceeds at a lower rate than predicted. The presence of clay hastens the consolidation process but does not greatly affect the previously observed relationship between permeability and void fraction. Studies of the migration of brine within polycrystalline salt specimens under stress indicate that the principal effect is the exclusion of brine as a result of consolidation, a process that evidently can proceed to completion. No clear effect of a temperature gradient could be identified. A previously reported linear increase with time of the reciprocal permeability of salt-crystal interfaces to brine was confirmed, though the rate of increase appears more nearly proportional to the product of sigma ΔP rather than sigma ΔP 2 (sigma is the uniaxial stress normal to the interface and ΔP is the hydraulic pressure drop). The new results suggest that a limiting permeability may be reached. A model for the permeability of salt-crystal interfaces to brine is developed that is reasonably consistent with the present results and may be used to predict the permeability of bedded salt. More measurements are needed, however, to choose between two limiting forms of the model

  8. Effect of water in salt repositories. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Baes, C.F. Jr.; Gilpatrick, L.O.; Kitts, F.G.; Bronstein, H.R.; Shor, A.J.

    1983-09-01

    Additional results confirm that during most of the consolidation of polycrystalline salt in brine, the previously proposed rate expression applies. The final consolidation, however, proceeds at a lower rate than predicted. The presence of clay hastens the consolidation process but does not greatly affect the previously observed relationship between permeability and void fraction. Studies of the migration of brine within polycrystalline salt specimens under stress indicate that the principal effect is the exclusion of brine as a result of consolidation, a process that evidently can proceed to completion. No clear effect of a temperature gradient could be identified. A previously reported linear increase with time of the reciprocal permeability of salt-crystal interfaces to brine was confirmed, though the rate of increase appears more nearly proportional to the product of sigma ..delta..P rather than sigma ..delta..P/sup 2/ (sigma is the uniaxial stress normal to the interface and ..delta..P is the hydraulic pressure drop). The new results suggest that a limiting permeability may be reached. A model for the permeability of salt-crystal interfaces to brine is developed that is reasonably consistent with the present results and may be used to predict the permeability of bedded salt. More measurements are needed, however, to choose between two limiting forms of the model.

  9. Structure and Function of a Novel ATPase that Interacts with Holliday Junction Resolvase Hjc and Promotes Branch Migration.

    Science.gov (United States)

    Zhai, Binyuan; DuPrez, Kevin; Doukov, Tzanko I; Li, Huan; Huang, Mengting; Shang, Guijun; Ni, Jinfeng; Gu, Lichuan; Shen, Yulong; Fan, Li

    2017-04-07

    Holliday junction (HJ) is a hallmark intermediate in DNA recombination and must be processed by dissolution (for double HJ) or resolution to ensure genome stability. Although HJ resolvases have been identified in all domains of life, there is a long-standing effort to search in prokaryotes and eukarya for proteins promoting HJ migration. Here, we report the structural and functional characterization of a novel ATPase, Sulfolobus islandicusPilT N-terminal-domain-containing ATPase (SisPINA), encoded by the gene adjacent to the resolvase Hjc coding gene. PINA is conserved in archaea and vital for S. islandicus viability. Purified SisPINA forms hexameric rings in the crystalline state and in solution, similar to the HJ migration helicase RuvB in Gram-negative bacteria. Structural analysis suggests that ATP binding and hydrolysis cause conformational changes in SisPINA to drive branch migration. Further studies reveal that SisPINA interacts with SisHjc and coordinates HJ migration and cleavage. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. The origin of sea salt in snow on Arctic sea ice and in coastal regions

    Directory of Open Access Journals (Sweden)

    F. Domine

    2004-01-01

    Full Text Available Snow, through its trace constituents, can have a major impact on lower tropospheric chemistry, as evidenced by ozone depletion events (ODEs in oceanic polar areas. These ODEs are caused by the chemistry of bromine compounds that originate from sea salt bromide. Bromide may be supplied to the snow surface by upward migration from sea ice, by frost flowers being wind-blown to the snow surface, or by wind-transported aerosol generated by sea spray. We investigate here the relative importance of these processes by analyzing ions in snow near Alert and Ny-Ålesund (Canadian and European high Arctic in winter and spring. Vertical ionic profiles in the snowpack on sea ice are measured to test upward migration of sea salt ions and to seek evidence for ion fractionation processes. Time series of the ionic composition of surface snow layers are investigated to quantify wind-transported ions. Upward migration of unfractionated sea salt to heights of at least 17cm was observed in winter snow, leading to Cl- concentration of several hundred µM. Upward migration thus has the potential to supply ions to surface snow layers. Time series show that wind can deposit aerosols to the top few cm of the snow, leading also to Cl- concentrations of several hundred µM, so that both diffusion from sea ice and wind transport can significantly contribute ions to snow. At Ny-Ålesund, sea salt transported by wind was unfractionated, implying that it comes from sea spray rather than frost flowers. Estimations based on our results suggest that the marine snowpack contains about 10 times more Na+ than the frost flowers, so that both the marine snowpack and frost flowers need to be considered as sea salt sources. Our data suggest that ozone depletion chemistry can significantly enhance the Br- content of snow. We speculate that this can also take place in coastal regions and contribute to propagate ODEs inland. Finally, we stress the need to measure snow physical parameters

  11. Mineralogical aspects of fluid migration in the Salt Block II experiment

    International Nuclear Information System (INIS)

    Lambert, S.J.

    1980-05-01

    A block of evaporite rock containing the mineral assemblage halite (88%) - polyhalite (8%) - sylvite (4%) was machined into a cylinder one meter in diameter and one meter high, and was fitted with an axial heater, thermocouples and an off-gas collection system. After about 100 days of heating, identification of mineral efflorescences at the heater hole (carnallite and bischofite) showed that a significant portion of the 111 grams of water recovered (out of around 8500 grams available in the rock) migrated as a liquid, not as a vapor. A microscopic examination of rock slices from within 15 cm of the heater hole (where the temperature was 100 to 200 0 C, and the gradient was 3 to 15 0 C/cm) revealed that: (1) fluid inclusions had migrated, but rarely across grain boundaries; (2) fluid inclusions had not been mobilized at distances greater than about 15 cm from the heater hole; and (3) intergranular liquid had been conspicuously mobilized within 15 cm of the heater hole

  12. Characterization of swollen structure of high-density polyelectrolyte brushes in salt solution by neutron reflectivity

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Motoyasu; Takahara, Atsushi [Institute for Materials Chemistry and Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Terayama, Yuki [Graduate School of Engineering, Kyushu University (Japan); Hino, Masahiro [Reactor Research Institute, Kyoto University (Japan); Ishihara, Kazuhiko, E-mail: takahara@cstf.kyushu-u.ac.j [Graduate School of Engineering, University of Tokyo (Japan)

    2009-08-01

    Zwitterionic and cationic polyelectrolyte brushes on quartz substrate were prepared by surface-initiated atom transfer radical polymerization of 2-(methacryloyloxy)ethyl phosphorylcholine (MPC) and 2-(methacryloyloxy)ethyltrimethylammonium chloride (METAC), respectively. The effects of ionic strength on brush structure and surface properties of densely grafted polyelectrolyte brushes were analysed by neutron reflectivity (NR) measurements. NR at poly(METAC)/D{sub 2}O and poly(MPC)/D{sub 2}O interface revealed that the grafted polymer chains were fairly extended from the substrate surface, while the thickness reduction of poly(METAC) brush was observed in 5.6 M NaCl/D{sub 2}O solution due to the screening of the repulsive interaction between polycations by hydrated salt ions. Interestingly, no structural change was observed in poly(MPC) brush even in a salt solution probably due to the unique interaction properties of phosphorylcholine units.

  13. Fibers and cylinders of cryptomelane-hollandite in Permian bedded salt, Palo Duro Basin, Texas

    International Nuclear Information System (INIS)

    Belkin, H.E.; Libelo, E.L.

    1987-01-01

    Fibers and thin-walled, hollow cylinders of cryptomelane-hollandite have been found in both the chevron and the clear salt from various drill cores in Permian bedded salt from the Palo Duro Basin, Texas. The authors have found fibers or cylinders from only the lower San Andres Formation units 4 and 5, the upper San Andres Formation, and the Salado-Transill salt. The fibers are inorganic, light to dark reddish brown, pleochroic, highly birefringent, filamentary single crystals, < 1 to ∼ 5 μm in diameter, with length-to-diameter ratios of at least 20:1. The fibers can be straight and/or curved, can bifurcate, can form loops, waves or spirals, and can be isolated or in parallel groups. Detailed petrographic analyses show no evidence for recrystallization or deformation of the enclosing salt after fiber formation. Although the authors observations do not provide a definitive explanation for fiber origin, they suggest that the fibers grew in situ by a solid-state diffusional process at low temperatures. The cylinders are pleochroic, highly birefringent, light to dark reddish brown, hollow, thin-walled, open-ended right cylinders, having a 1- to 2-μm wall thickness and variable lengths and diameters. There also appear to be single crystals of cryptomelane-hollandite, but these are found almost entirely in fluid inclusions in the chevron and clear salt. Their presence in the primary halite suggests that they were formed contemporaneously with the chevron structure and were accidentally trapped in the fluid inclusions. The observation of cylinders partially or completely enclosed by salt stratigraphically above large fluid inclusions suggests that natural downward fluid-inclusion migration has occurred, in response to the geothermal gradient

  14. How social structure changes in Chinese global cities: Synthesizing globalization, migration and institutional factors in Beijing

    NARCIS (Netherlands)

    Shi, Q.; Liu, T.; Musterd, S.; Cao, G.

    2017-01-01

    Recent studies on the social structural change in global cities have recognized globalization, migration, and institutional factors as three main forces underlying this process. However, effects of these factors have rarely been synthetically examined and the social structure of emerging Chinese

  15. Salt Tolerance in Soybean

    Institute of Scientific and Technical Information of China (English)

    Tsui-Hung Phang; Guihua Shao; Hon-Ming Lam

    2008-01-01

    Soybean is an Important cash crop and its productivity is significantly hampered by salt stress. High salt Imposes negative impacts on growth, nodulation, agronomy traits, seed quality and quantity, and thus reduces the yield of soybean. To cope with salt stress, soybean has developed several tolerance mechanisms, including: (I) maintenance of ion homeostasis; (ii) adjustment in response to osmotic stress; (iii) restoration of osmotic balance; and (iv) other metabolic and structural adaptations. The regulatory network for abiotic stress responses in higher plants has been studied extensively in model plants such as Arabidopsis thaliana. Some homologous components involved in salt stress responses have been identified in soybean. In this review, we tried to integrate the relevant works on soybean and proposes a working model to descdbe Its salt stress responses at the molecular level.

  16. Ionic diffusion and salt dissociation conditions of lithium liquid crystal electrolytes.

    Science.gov (United States)

    Saito, Yuria; Hirai, Kenichi; Murata, Shuuhei; Kishii, Yutaka; Kii, Keisuke; Yoshio, Masafumi; Kato, Takashi

    2005-06-16

    Salt dissociation conditions and dynamic properties of ionic species in liquid crystal electrolytes of lithium were investigated by a combination of NMR spectra and diffusion coefficient estimations using the pulsed gradient spin-echo NMR techniques. Activation energies of diffusion (Ea) of ionic species changed with the phase transition of the electrolyte. That is, Ea of the nematic phase was lower than that of the isotropic phase. This indicates that the aligned liquid crystal molecules prepared efficient conduction pathways for migration of ionic species. The dissociation degree of the salt was lower compared with those of the conventional electrolyte solutions and polymer gel electrolytes. This is attributed to the low concentration of polar sites, which attract the dissolved salt and promote salt dissociation, on the liquid crystal molecules. Furthermore, motional restriction of the molecules due to high viscosity and molecular oriented configuration in the nematic phase caused inefficient attraction of the sites for the salt. With a decreased dissolved salt concentration of the liquid crystal electrolyte, salt dissociation proceeded, and two diffusion components attributed to the ion and ion pair were detected independently. This means that the exchange rate between the ion and the ion pair is fairly slow once the salt is dissociated in the liquid crystal electrolytes due to the low motility of the medium molecules that initiate salt dissociation.

  17. Elucidating the Solvation Structure and Dynamics of Lithium Polysulfides Resulting from Competitive Salt and Solvent Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Rajput, Nav Nidhi; Murugesan, Vijayakumar; Shin, Yongwoo; Han, Kee Sung; Lau, Kah Chun; Chen, Junzheng; Liu, Jun; Curtiss, Larry A.; Mueller, Karl T.; Persson, Kristin A.

    2017-04-10

    Fundamental molecular level understanding of functional properties of liquid solutions provides an important basis for designing optimized electrolytes for numerous applica-tions. In particular, exhaustive knowledge of solvation structure, stability and transport properties is critical for developing stable electrolytes for fast charging and high energy density next-generation energy storage systems. Here we report the correlation between solubility, solvation structure and translational dynamics of a lithium salt (Li-TFSI) and polysulfides species using well-benchmarked classical molecular dynamics simulations combined with nuclear magnetic resonance (NMR). It is observed that the polysulfide chain length has a significant effect on the ion-ion and ion-solvent interaction as well as on the diffusion coefficient of the ionic species in solution. In particular, extensive cluster formation is observed in lower order poly-sulfides (Sx2-; x≤4), whereas the longer polysulfides (Sx2-; x>4) show high solubility and slow dynamics in the solu-tion. It is observed that optimal solvent/salt ratio is essen-tial to control the solubility and conductivity as the addi-tion of Li salt increases the solubility but decreases the mo-bility of the ionic species. This work provides a coupled theoretical and experimental study of bulk solvation struc-ture and transport properties of multi-component electro-lyte systems, yielding design metrics for developing optimal electrolytes with improved stability and solubility.

  18. Thermomigration of fluid inclusions in rock salt. Implications for the disposal of nuclear wastes

    International Nuclear Information System (INIS)

    Noack, W.; Runge, K.

    1984-01-01

    A mathematical model has been suggested to predict the time-dependent accumulation of brine at nuclear waste packages emplaced in a rock salt repository owing to thermomigration of brine inclusions. The model is based mainly on a description of the migration rate as a function of the temperature, temperature gradient, inclusion size and gas/liquid ratio of inclusions. Other factors are treated merely as disturbing quantities with respect to the migration rate. (author)

  19. Synthesis of complex oxides with garnet structure by spray drying of an aqueous salt solution

    Science.gov (United States)

    Makeenko, A. V.; Larionova, T. V.; Klimova-Korsmik, O. G.; Starykh, R. V.; Galkin, V. V.; Tolochko, O. V.

    2017-04-01

    The use of spray drying to obtain powders of complex oxides with a garnet structure has demonstrated. The processes occurring during heating of the synthesized oxide-salt product, leading to the formation of a material with a garnet structure, have been investigated using DTA, TGA, XPS, and XRD. It has been shown that a single-phase garnet structure of system (Y x Gd(3- x))3Al5O12 can be synthesized over the entire range of compositions.

  20. Evaluation of mapping results of the textural features of the Gorleben-Bank within the Gorleben salt dome, Germany

    Energy Technology Data Exchange (ETDEWEB)

    Kuehnlenz, Tatjana; Hammer, Joerg; Mingerzahn, Gerhard [Bundesanstalt fuer Geowissenschaften und Rohstoffe, Hannover (Germany); Sassnowski, Marco; Kutowski, Joachim [Deutsche Gesellschaft zum Bau und Betrieb von Endlagern fuer Abfallstoffe mbH, Peine (Germany)

    2014-07-01

    The ''Gorleben-Bank'' (z3OSM) is a marker horizon within the ''Orangesalz'' (z3OS) of the ''Leine-Folge'' (z3) in the Gorleben salt dome. In some areas the Gorleben-Bank and/or the surrounding rocks contain brines and gases. The occurrence of brines and gases could be hazardous for a repository. Therefore it is important to analyse the lithological and structural characteristics of the Gorleben-Bank. As part of the project ''Continuation of exploration of the Gorleben salt dome'', all exposures of the Gorleben-Bank in drifts, shafts and exploration boreholes were documented and incorporated within a database. Analogous to Baeuerle (2000), seven zones were identified within the Gorleben-Bank from bottom to top. The total thickness of the Gorleben-Bank and the thickness of the zones relevant for migration and storage of brines and gases were considered in this paper. The fissures and the zone of secondary mineralisation of the Gorleben-Bank (Zone IV), generated during the halotectonic processes, as well as brines in the Gorleben-Bank and its surrounding rocks, were analysed regarding their genesis and spatial distribution in the salt dome. These analyses allow conclusions about deformation behaviour of the Gorleben-Bank and its potential for storage of solutions and migration capability for brines and gases. With the program GEOravis some database contents e.g. the thickness of the Gorleben-Bank or location of brine adits were visualised in 3D space for better spatial understanding.

  1. Molecular dynamics simulations of the structure and single-particle dynamics of mixtures of divalent salts and ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Gómez-González, Víctor; Docampo-Álvarez, Borja; Gallego, Luis J.; Varela, Luis M., E-mail: luismiguel.varela@usc.es [Grupo de Nanomateriais e Materia Branda, Departamento de Física da Materia Condensada, Universidade de Santiago de Compostela, Campus Vida s/n, E-15782 Santiago de Compostela (Spain); Cabeza, Oscar [Facultade de Ciencias, Universidade da Coruña, Campus A Zapateira s/n, E-15008 A Coruña (Spain); Fedorov, Maxim [Department of Physics, Scottish University Physics Alliance (SUPA), University of Strathclyde, John Anderson Bldg., 107 Rottenrow East, Glasgow G4 0NG (United Kingdom); Lynden-Bell, Ruth M. [Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW (United Kingdom)

    2015-09-28

    We report a molecular dynamics study of the structure and single-particle dynamics of mixtures of a protic (ethylammonium nitrate) and an aprotic (1-butyl-3-methylimidazolium hexaflurophosphate [BMIM][PF{sub 6}]) room-temperature ionic liquids doped with magnesium and calcium salts with a common anion at 298.15 K and 1 atm. The solvation of these divalent cations in dense ionic environments is analyzed by means of apparent molar volumes of the mixtures, radial distribution functions, and coordination numbers. For the protic mixtures, the effect of salt concentration on the network of hydrogen bonds is also considered. Moreover, single-particle dynamics of the salt cations is studied by means of their velocity autocorrelation functions and vibrational densities of states, explicitly analyzing the influence of salt concentration, and cation charge and mass on these magnitudes. The effect of the valency of the salt cation on these properties is considered comparing the results with those for the corresponding mixtures with lithium salts. We found that the main structural and dynamic features of the local solvation of divalent cations in ionic liquids are similar to those of monovalent salts, with cations being localized in the polar nanoregions of the bulk mixture coordinated in monodentate and bidentate coordination modes by the [NO{sub 3}]{sup −} and [PF{sub 6}]{sup −} anions. However, stronger electrostatic correlations of these polar nanoregions than in mixtures with salts with monovalent cations are found. The vibrational modes of the ionic liquid (IL) are seen to be scarcely affected by the addition of the salt, and the effect of mass and charge on the vibrational densities of states of the dissolved cations is reported. Cation mass is seen to exert a deeper influence than charge on the low-frequency vibrational spectra, giving a red shift of the vibrational modes and a virtual suppression of the higher energy vibrational modes for the heavier Ca{sup 2

  2. Molecular dynamics simulations of the structure and single-particle dynamics of mixtures of divalent salts and ionic liquids

    International Nuclear Information System (INIS)

    Gómez-González, Víctor; Docampo-Álvarez, Borja; Gallego, Luis J.; Varela, Luis M.; Cabeza, Oscar; Fedorov, Maxim; Lynden-Bell, Ruth M.

    2015-01-01

    We report a molecular dynamics study of the structure and single-particle dynamics of mixtures of a protic (ethylammonium nitrate) and an aprotic (1-butyl-3-methylimidazolium hexaflurophosphate [BMIM][PF 6 ]) room-temperature ionic liquids doped with magnesium and calcium salts with a common anion at 298.15 K and 1 atm. The solvation of these divalent cations in dense ionic environments is analyzed by means of apparent molar volumes of the mixtures, radial distribution functions, and coordination numbers. For the protic mixtures, the effect of salt concentration on the network of hydrogen bonds is also considered. Moreover, single-particle dynamics of the salt cations is studied by means of their velocity autocorrelation functions and vibrational densities of states, explicitly analyzing the influence of salt concentration, and cation charge and mass on these magnitudes. The effect of the valency of the salt cation on these properties is considered comparing the results with those for the corresponding mixtures with lithium salts. We found that the main structural and dynamic features of the local solvation of divalent cations in ionic liquids are similar to those of monovalent salts, with cations being localized in the polar nanoregions of the bulk mixture coordinated in monodentate and bidentate coordination modes by the [NO 3 ] − and [PF 6 ] − anions. However, stronger electrostatic correlations of these polar nanoregions than in mixtures with salts with monovalent cations are found. The vibrational modes of the ionic liquid (IL) are seen to be scarcely affected by the addition of the salt, and the effect of mass and charge on the vibrational densities of states of the dissolved cations is reported. Cation mass is seen to exert a deeper influence than charge on the low-frequency vibrational spectra, giving a red shift of the vibrational modes and a virtual suppression of the higher energy vibrational modes for the heavier Ca 2+ cations. No qualitative

  3. Production of structured lipids: acyl migration during enzymatic interesterification and downstream processing

    DEFF Research Database (Denmark)

    Xu, Xuebing

    1997-01-01

    Production of structured lipids by lipase-catalyzed interesterification attracts great interests recently. Structured lipids are defined, in this article, as triacylglycerols which contain both medium or short chain fatty acids and long chain fatty acids, each groups locating specifically in the sn......-2 position or sn-1,3 positions of glycerol backbone. These kinds of lipids are reported to be promising for both enteral and parenteral nutrition. However, acyl migration occurs in the reaction stage and downstream purification process. This side-reaction causes by-products which are harmful...

  4. Gas anti-solvent precipitation assisted salt leaching for generation of micro- and nano-porous wall in bio-polymeric 3D scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    Flaibani, Marina; Elvassore, Nicola, E-mail: nicola.elvassore@unipd.it

    2012-08-01

    The mass transport through biocompatible and biodegradable polymeric 3D porous scaffolds may be depleted by non-porous impermeable internal walls. As consequence the concentration of metabolites and growth factors within the scaffold may be heterogeneous leading to different cell fate depending on spatial cell location, and in some cases it may compromise cell survival. In this work, we fabricated polymeric scaffolds with micro- and nano-scale porosity by developing a new technique that couples two conventional scaffold production methods: solvent casting-salt leaching and gas antisolvent precipitation. 10-15 w/w solutions of a hyaluronic benzyl esters (HYAFF11) and poly-(lactic acid) (PLA) were used to fill packed beds of 0.177-0.425 mm NaCl crystals. The polymer precipitation in micro and nano-porous structures between the salt crystals was induced by high-pressure gas, then its flushing extracted the residual solvent. The salt was removed by water-wash. Morphological analysis by scanning electron microscopy showed a uniform porosity ({approx} 70%) and a high interconnectivity between porous. The polymeric walls were porous themselves counting for 30% of the total porosity. This wall porosity did not lead to a remarkable change in compressive modulus, deformation, and rupture pressure. Scaffold biocompatibility was tested with murine muscle cell line C2C12 for 4 and 7 days. Viability analysis and histology showed that micro- and nano-porous scaffolds are biocompatible and suitable for 3D cell culture promoting cell adhesion on the polymeric wall and allowing their proliferation in layers. Micro- and nano-scale porosities enhance cell migration and growth in the inner part of the scaffold. - Highlights: Black-Right-Pointing-Pointer Gas anti-solvent precipitation and salt leaching for scaffold fabrication. Black-Right-Pointing-Pointer Hyaluronic benzyl esters (HYAFF11) and poly-(lactic acid) (PLA) sponges. Black-Right-Pointing-Pointer Gas anti-solvent precipitation

  5. Gas anti-solvent precipitation assisted salt leaching for generation of micro- and nano-porous wall in bio-polymeric 3D scaffolds

    International Nuclear Information System (INIS)

    Flaibani, Marina; Elvassore, Nicola

    2012-01-01

    The mass transport through biocompatible and biodegradable polymeric 3D porous scaffolds may be depleted by non-porous impermeable internal walls. As consequence the concentration of metabolites and growth factors within the scaffold may be heterogeneous leading to different cell fate depending on spatial cell location, and in some cases it may compromise cell survival. In this work, we fabricated polymeric scaffolds with micro- and nano-scale porosity by developing a new technique that couples two conventional scaffold production methods: solvent casting-salt leaching and gas antisolvent precipitation. 10–15 w/w solutions of a hyaluronic benzyl esters (HYAFF11) and poly-(lactic acid) (PLA) were used to fill packed beds of 0.177–0.425 mm NaCl crystals. The polymer precipitation in micro and nano-porous structures between the salt crystals was induced by high-pressure gas, then its flushing extracted the residual solvent. The salt was removed by water-wash. Morphological analysis by scanning electron microscopy showed a uniform porosity (∼ 70%) and a high interconnectivity between porous. The polymeric walls were porous themselves counting for 30% of the total porosity. This wall porosity did not lead to a remarkable change in compressive modulus, deformation, and rupture pressure. Scaffold biocompatibility was tested with murine muscle cell line C2C12 for 4 and 7 days. Viability analysis and histology showed that micro- and nano-porous scaffolds are biocompatible and suitable for 3D cell culture promoting cell adhesion on the polymeric wall and allowing their proliferation in layers. Micro- and nano-scale porosities enhance cell migration and growth in the inner part of the scaffold. - Highlights: ► Gas anti-solvent precipitation and salt leaching for scaffold fabrication. ► Hyaluronic benzyl esters (HYAFF11) and poly-(lactic acid) (PLA) sponges. ► Gas anti-solvent precipitation induces nano-porous structures. ► Scaffolds are biocompatible and

  6. Batch Kd measurements of nuclides to estimate migration potential at the proposed Waste Isolation Pilot Plant in New Mexico

    International Nuclear Information System (INIS)

    Serne, R.J.; Rai, D.; Mason, M.J.; Molecke, M.A.

    1977-01-01

    Laboratory measurements to determine the sorption distribution coefficients, Kd, of radionuclides present in, and potentially leached from, radioactive wastes, in contact with representative geologic media, have been conducted. The nuclides studied include Cs, Sr, Tc, Ru, Sb, Ce, Eu, Pu, Np, Cm, Am, U, and Pa. The crushed rock materials used were from the vicinity of the Waste Isolation Pilot Plant, a project to isolate radioactive wastes in a bedded salt facility, near Carlsbad, New Mexico. Solutions used consist of salt brine and groundwater, specific to the WIPP site, plus distilled water, for laboratory intercomparisons. The batch Kd data reported, plus data from sorption and migration measurements being conducted or planned elsewhere, will be used to evaluate the potential for radionuclide migration from the bedded salt WIPP facility. The data can be used for transport modeling and for safety assessment determinations

  7. Capitalist development and internal migration in Nigeria.

    Science.gov (United States)

    Akor, R I; Mou, D

    1986-12-01

    The authors analyze internal migration trends in Nigeria by examining individual household strategies and how they have adapted to structural changes brought about by colonial rule and capitalist development. The first section of this article describes the structural changes that started the process of labor migration. The second section deals with post-independence industrialization and the consequent rural-urban migration. The final section analyzes the consequences of these migration patterns for urban growth and rural productivity.

  8. Tandem dinucleophilic cyclization of cyclohexane-1,3-diones with pyridinium salts

    Directory of Open Access Journals (Sweden)

    Mostafa Kiamehr

    2013-06-01

    Full Text Available The cyclization of cyclohexane-1,3-diones with various substituted pyridinium salts afforded functionalized 8-oxa-10-aza-tricyclo[7.3.1.02,7]trideca-2(7,11-dienes. The reaction proceeds by regioselective attack of the central carbon atom of the 1,3-dicarbonyl unit to 4-position of the pyridinium salt and subsequent cyclization by base-assisted proton migration and nucleophilic addition of the oxygen atom to the 2-position, as was elucidated by DFT computations. Fairly extensive screening of bases and additives revealed that the presence of potassium cations is essential for formation of the product.

  9. Asse salt mine nuclear waste repository simulation experiments

    International Nuclear Information System (INIS)

    Coyle, A.J.

    1983-01-01

    The field tests underway in Asse, Federal Republic of Germany are dicected toward the development of test plans, techniques and equipment to be used in Exploratory Shafts or At Depth Test Facilities confirmation tests. These simulated repository tests will also provide information which address the following issues: brine migration (liquid and vapor); radiation effects of gamma rays; gas generation caused by radiation and corrosion; accelerated corrosion and leaching; altered properties of salt (the effects of heat, radiation and brine); and the effects of heat and radiation on test assemblies, instruments, and various materials exposed to repository conditions. This paper is a status of the first 82 days of operation of the Asse Brine Migration Tests, which were initiated on May 25, 1983. 6 references

  10. Salt bridge as a gatekeeper against partial unfolding.

    Science.gov (United States)

    Hinzman, Mark W; Essex, Morgan E; Park, Chiwook

    2016-05-01

    Salt bridges are frequently observed in protein structures. Because the energetic contribution of salt bridges is strongly dependent on the environmental context, salt bridges are believed to contribute to the structural specificity rather than the stability. To test the role of salt bridges in enhancing structural specificity, we investigated the contribution of a salt bridge to the energetics of native-state partial unfolding in a cysteine-free version of Escherichia coli ribonuclease H (RNase H*). Thermolysin cleaves a protruding loop of RNase H(*) through transient partial unfolding under native conditions. Lys86 and Asp108 in RNase H(*) form a partially buried salt bridge that tethers the protruding loop. Investigation of the global stability of K86Q/D108N RNase H(*) showed that the salt bridge does not significantly contribute to the global stability. However, K86Q/D108N RNase H(*) is greatly more susceptible to proteolysis by thermolysin than wild-type RNase H(*) is. The free energy for partial unfolding determined by native-state proteolysis indicates that the salt bridge significantly increases the energy for partial unfolding by destabilizing the partially unfolded form. Double mutant cycles with single and double mutations of the salt bridge suggest that the partially unfolded form is destabilized due to a significant decrease in the interaction energy between Lys86 and Asp108 upon partial unfolding. This study demonstrates that, even in the case that a salt bridge does not contribute to the global stability, the salt bridge may function as a gatekeeper against partial unfolding that disturbs the optimal geometry of the salt bridge. © 2016 The Protein Society.

  11. Using the characteristics of the structure of the upper Frasnian salt bearing formation in prospecting for oil deposits in the Pripyat depression

    Energy Technology Data Exchange (ETDEWEB)

    Yeroshina, D.M.; Kislik, V.Z.; Sinichka, A.M.; Vysotskiy, E.A.

    1984-01-01

    The possibility is shown of using the structure of the upper Frasnian salt bearing formation to establish ancient depressions and uplifts. A gradual wedge out of the lower strata of rock salt towards the domes of the ancient uplifts occurs. It is recommended that several reflecting levels be built up in the base of the salt bearing formation to record the behavior of these strata.

  12. Involvement of bacterial migration in the development of complex multicellular structures in Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Klausen, Mikkel; Aaes-Jorgensen, A.; Molin, Søren

    2003-01-01

    development, we have performed an investigation with time-lapse confocal laser scanning microscopy of biofilms formed by various combinations of colour-coded P. aeruginosa wild type and motility mutants. We show that mushroom-shaped multicellular structures in P. aeruginosa biofilms can form in a sequential...... process involving a non-motile bacterial subpopulation and a migrating bacterial subpopulation. The non-motile bacteria form the mushroom stalks by growth in certain foci of the biofilm. The migrating bacteria form the mushroom caps by climbing the stalks and aggregating on the tops in a process which...

  13. Response of Soil Fungi Community Structure to Salt Vegetation Succession in the Yellow River Delta.

    Science.gov (United States)

    Wang, Yan-Yun; Guo, Du-Fa

    2016-10-01

    High-throughput sequencing technology was used to reveal the composition and distribution of fungal community structure in the Yellow River Delta under bare land and four kinds of halophyte vegetation (saline seepweed, Angiospermae, Imperata and Apocynum venetum [A. venetum]). The results showed that the soil quality continuously improved with the succession of salt vegetation types. The soil fungi richness of mild-salt communities (Imperata and A. venetum) was relatively higher, with Shannon index values of 5.21 and 5.84, respectively. The soil fungi richness of severe-salt-tolerant communities (saline seepweed, Angiospermae) was relatively lower, with Shannon index values of 4.64 and 4.66, respectively. The UniFrac metric values ranged from 0.48 to 0.67 when the vegetation was in different succession stages. A total of 60,174 valid sequences were obtained for the five vegetation types, and they were classified into Ascomycota, Basidiomycota, Chytridiomycota, Glomeromycota and Mucoromycotina. Ascomycota had the greatest advantage among plant communities of Imperata and A. venetum, as indicated by relative abundances of 2.69 and 69.97 %, respectively. Basidiomycota had the greatest advantage among mild-salt communities of saline seepweed and Angiospermae, with relative abundances of 9.43 and 6.64 %, respectively. Soil physical and chemical properties were correlated with the distribution of the fungi, and Mucor was significantly correlated with soil moisture (r = 0.985; P Soil quality, salt vegetation and soil fungi were influenced by each other.

  14. Superconductivity of Rock-Salt Structure LaO Epitaxial Thin Film.

    Science.gov (United States)

    Kaminaga, Kenichi; Oka, Daichi; Hasegawa, Tetsuya; Fukumura, Tomoteru

    2018-06-06

    We report a superconducting transition in a LaO epitaxial thin film with the superconducting transition onset temperature ( T c ) at around 5 K. This T c is higher than those of other lanthanum monochalcogenides and opposite to their chemical trend: T c = 0.84, 1.02, and 1.48 K for LaX (X = S, Se, Te), respectively. The carrier control resulted in a dome-shaped T c as a function of electron carrier density. In addition, the T c was significantly sensitive to epitaxial strain in spite of the highly symmetric crystal structure. This rock-salt superconducting LaO could be a building block to design novel superlattice superconductors.

  15. Synthetic seismic monitoring using reverse-time migration and Kirchhoff migration for CO2 sequestration in Korea

    Science.gov (United States)

    Kim, W.; Kim, Y.; Min, D.; Oh, J.; Huh, C.; Kang, S.

    2012-12-01

    During last two decades, CO2 sequestration in the subsurface has been extensively studied and progressed as a direct tool to reduce CO2 emission. Commercial projects such as Sleipner, In Salah and Weyburn that inject more than one million tons of CO2 per year are operated actively as well as test projects such as Ketzin to study the behavior of CO2 and the monitoring techniques. Korea also began the CCS (CO2 capture and storage) project. One of the prospects for CO2 sequestration in Korea is the southwestern continental margin of Ulleung basin. To monitor the behavior of CO2 underground for the evaluation of stability and safety, several geophysical monitoring techniques should be applied. Among various geophysical monitoring techniques, seismic survey is considered as the most effective tool. To verify CO2 migration in the subsurface more effectively, seismic numerical simulation is an essential process. Furthermore, the efficiency of the seismic migration techniques should be investigated for various cases because numerical seismic simulation and migration test help us accurately interpret CO2 migration. In this study, we apply the reverse-time migration and Kirchhoff migration to synthetic seismic monitoring data generated for the simplified model based on the geological structures of Ulleung basin in Korea. Synthetic seismic monitoring data are generated for various cases of CO2 migration in the subsurface. From the seismic migration images, we can investigate CO2 diffusion patterns indirectly. From seismic monitoring simulation, it is noted that while the reverse-time migration generates clear subsurface images when subsurface structures are steeply dipping, Kirchhoff migration has an advantage in imaging horizontal-layered structures such as depositional sediments appearing in the continental shelf. The reverse-time migration and Kirchhoff migration present reliable subsurface images for the potential site characterized by stratigraphical traps. In case of

  16. Effects of gaseous radioactive nuclides on the design and operation of repositories for spent LWR fuel in rock salt

    International Nuclear Information System (INIS)

    Jenks, G.H.

    1979-12-01

    Information relating to the identities and amounts of gaseous radionuclides present in spent LWR fuel and to their release from canistered spent fuel under plausible storage and disposal conditions was assembled, reviewed, and analyzed. Information was also reviewed and analyzed on several other subjects that relate to the integrity of the carbon steel canister in which the spent fuel is to be encapsulated and to the expected rates of transfer of gaseous radionuclides through crushed salt backfill within a disposal room in a reference repository in rock salt. The advantages and disadvantages were considered for several different canister-backfill materials, and recommendations were made regarding preferred materials. Other recommendations relate to encapsulation procedures and specifications and to needs for additional experimental studies. The objective of this work was to provide reference information, conclusions, and recommendations that could be used to establish design and operating conditions and procedures for a bedded salt repository for spent LWR fuel and that could also be used to help evaluate the safety of the repository. The results of this work will also generally apply to spent fuel repositories in domal salt. However, because the domal salt may have little or no brine inclusions within it, there may be little or no possibility that brine will migrate into open spaces around an emplaced canister. Addordingly, some of the concerns that result from the possible occurrence of brine migration in bedded salt may be of no importance in domal salt

  17. 3D Gravity Modeling of Complex Salt Features in the Southern Gulf of Mexico

    Directory of Open Access Journals (Sweden)

    Mauricio Nava-Flores

    2016-01-01

    Full Text Available We present a three-dimensional (3D gravity modeling and inversion approach and its application to complex geological settings characterized by several allochthonous salt bodies embedded in terrigenous sediments. Synthetic gravity data were computed for 3D forward modeling of salt bodies interpreted from Prestack Depth Migration (PSDM seismic images. Density contrasts for the salt bodies surrounded by sedimentary units are derived from density-compaction curves for the northern Gulf of Mexico’s oil exploration surveys. By integrating results from different shape- and depth-source estimation algorithms, we built an initial model for the gravity anomaly inversion. We then applied a numerically optimized 3D simulated annealing gravity inversion method. The inverted 3D density model successfully retrieves the synthetic salt body ensemble. Results highlight the significance of integrating high-resolution potential field data for salt and subsalt imaging in oil exploration.

  18. Crystal structure of bile salt hydrolase from Lactobacillus salivarius.

    Science.gov (United States)

    Xu, Fuzhou; Guo, Fangfang; Hu, Xiao Jian; Lin, Jun

    2016-05-01

    Bile salt hydrolase (BSH) is a gut-bacterial enzyme that negatively influences host fat digestion and energy harvesting. The BSH enzyme activity functions as a gateway reaction in the small intestine by the deconjugation of glycine-conjugated or taurine-conjugated bile acids. Extensive gut-microbiota studies have suggested that BSH is a key mechanistic microbiome target for the development of novel non-antibiotic food additives to improve animal feed production and for the design of new measures to control obesity in humans. However, research on BSH is still in its infancy, particularly in terms of the structural basis of BSH function, which has hampered the development of BSH-based strategies for improving human and animal health. As an initial step towards the structure-function analysis of BSH, C-terminally His-tagged BSH from Lactobacillus salivarius NRRL B-30514 was crystallized in this study. The 1.90 Å resolution crystal structure of L. salivarius BSH was determined by molecular replacement using the structure of Clostridium perfringens BSH as a starting model. It revealed this BSH to be a member of the N-terminal nucleophile hydrolase superfamily. Crystals of apo BSH belonged to space group P21212, with unit-cell parameters a = 90.79, b = 87.35, c = 86.76 Å (PDB entry 5hke). Two BSH molecules packed perfectly as a dimer in one asymmetric unit. Comparative structural analysis of L. salivarius BSH also identified potential residues that contribute to catalysis and substrate specificity.

  19. Nuclear waste repository simulation experiments, Asse salt mine, Federal Republic of Germany. Annual report 1984

    International Nuclear Information System (INIS)

    Rothfuchs, T.; Feddersen, H.K.; Schwarzianeck, P.; Staupendahl, G.; Coyle, A.J.; Eckert, J.; Kalia, H.

    1986-07-01

    This is the second joint annual report (1984) on experiments simulating a nuclear waste repository at the 800-m (2624-ft) level of the Asse salt mine in the Federal Republic of Germany. This report describes the Asse salt mine, the test equipment, and the pretest properties of the salt in the mine and in the vicinity of the test area. Also included are test data for the first 19 months of operation on the following: brine migration rates, thermal mechanical behavior of the salt (including room closure, stress reading, and thermal profiles), and borehole gas pressures. In addition to field data, laboratory analyses of results are included in this report. The duration of the experiment will be 2 years, ending in December 1985

  20. AMS fabric and structural record along a strain gradient in an extrusive salt diapir (Kuh-e-Namak, Dashti, Iran)

    Science.gov (United States)

    Zavada, Prokop; Schulmann, Karel; Lexa, Ondrej; Machek, Matej; Roxerova, Zuzana; Kusbach, Vladimir

    2016-04-01

    The AMS record and the halite fabrics on meso- and micro-scale were studied in detail on a well exposed salt extrusive body in Iran. In the Kuh-e-Namak (Dashti) mountain salt diapir, the deformation structures in colored salt are displayed along longitudinal profiles across the dome and two glaciers that extend from the NE and SW edge of the dome. The profiles from the dome to the frontal parts of the glaciers reveal a continuous strain gradient associated with transposition of the domal salt fabrics by axial fold cleavage development during flow of rock salt over the ridges in the channel. The extruded salt belongs to the Hormuz sequence of Neo-Proterozoic to Early Cambrian age. From central dome towards especially the northern namakier, structural record revealed zonation from; 1) gravitational collapse related recumbent isoclinal folds in the dome, 2) flat normal shears at the edge of the dome, 3) collapsed vertical layering into flat lying transpositional fabric at the toe of the dome, 4) penetrative fold cleavage transposition of earlier fabrics above the topographical ridge in the base of the flow, locally displaying strong transversal constrictional fabrics, 5) banded mylonites with isoclinal rootless folds in subhorizontally banded frontal and marginal domain of the glacier. The AMS fabric in the rock salt is generated primarily by hematite dispersed in the recrystallized halite. The AMS exhibits three main types of fabric symmetry from clustered all directions (K1,K2,K3, orthogonal fabric) to clustered K1 directions with girdle forming K2,K3 axes and clustered K3 directions with girdle of K1 and K2 directions. The AMS fabric clearly reflects the macroscopic fabric transpositions along the entire investigated strain gradient in the rock salt. Magnetic fabrics reveal continuous trends from bimodal to semi-girdle distribution of foliations in folded and cleavage present regions, to magnetic lineation clustering perpendicular to flow in completely refolded

  1. Performance analysis of conceptual waste package designs in salt repositories

    International Nuclear Information System (INIS)

    Jansen, G. Jr.; Raines, G.E.; Kircher, J.F.

    1984-01-01

    A performance analysis of commercial high-level waste and spent fuel conceptual package designs in reference repositories in three salt formations was conducted with the WAPPA waste package code. Expected conditions for temperature, stress, brine composition, radiation level, and brine flow rate were used as boundary conditions to compute expected corrosion of a thick-walled overpack of 1025 wrought steel. In all salt formations corrosion by low Mg salt-dissolution brines typical of intrusion scenarios was too slow to cause the package to fail for thousands of years after burial. In high Mg brines judged typical of thermally migrating brines in bedded salt formations, corrosion rates which would otherwise have caused the packages to fail within a few hundred years were limited by brine availability. All of the brine reaching the package was consumed by reaction with the iron in the overpack, thus preventing further corrosion. Uniform brine distribution over the package surface was an important factor in predicting long package lifetimes for the high Mg brines. 14 references, 15 figures

  2. Halocinèse précoce associée au rifting jurassique dans l'Atlas central de Tunisie (région de Majoura El Hfay)

    Science.gov (United States)

    Tanfous Amri, Dorra; Bédir, Mourad; Soussi, Mohamed; Azaiez, Hajer; Zitouni, Lahoussine; Hédi Inoubli, M.; Ben Boubaker, Kamel

    2005-05-01

    Seismic and sequence stratigraphy analyses, petroleum-well control and surface data studies of the Majoura-El Hfay region in the Central Atlas of Tunisia had led to identify and calibrate Jurassic seismic horizons. Seismic stratigraphic sections, seismic tectonics analyses, isochron and isopach mapping of Jurassic sequences show a differentiated structuring of platform and depocentre blocks limited by deep-seated NE-SW, north-south east-west and NW-SE faults intruded by Upper Triassic salt. The early salt migration seems to have started by the platform fracturing during the Lower Liassic rifting event. These movements are fossilized by thickness variations of Jurassic horizons, aggrading and retrograding onlap and toplap structures between subsiding rim-syncline gutters and high platform flanks intruded by salt pillows and domes. The salt migration is also attested by Middle and Upper Jurassic space depocentre migrations. Around the Majoura-El Hfay study blocks bounded by master faults, Triassic salt have pierced the Cretaceous and Tertiary sedimentary cover in a salt diapir extrusion and salt wall structures. To cite this article: D. Tanfous Amri et al., C. R. Geoscience 337 (2005).

  3. Imaging of salt structure. 2; Gan`enso kozo no imaging. 2

    Energy Technology Data Exchange (ETDEWEB)

    Akama, K; Saeki, T [Japan National Oil Corp., Tokyo (Japan). Technology Research Center; Matsuoka, T [Japan Petroleum Exploration Corp., Tokyo (Japan)

    1997-05-27

    With respect to a velocity model structuring method using depth focusing analysis (DFA) as a depth image processing technology used for elastic wave exploration, its practicability was discussed. First, synthetic data were used to extract problems in the DFA. The problems were extracted by using a model with constant velocity as an initial model, deciding on the sequential structures from the higher order, and estimating velocity and depth of each layer by using a model fitting type method. In its application to field data, characteristic records include those for rock salt beds distributed in a sheet form and the folding structure associated with the growth thereof, as acquired in offshore seismic exploration carried out in the eastern part of Gulf of Mexico. The conclusion is that the DFA is a method that can derive a velocity model with required accuracy by using a minimum number of repetition even against relatively complex structures. Particularly, the quick convergence from the initial model with a constant velocity until a certain accuracy is reached is a noteworthy advantage. 3 refs., 6 figs.

  4. Numerical Modeling Tools for the Prediction of Solution Migration Applicable to Mining Site

    International Nuclear Information System (INIS)

    Martell, M.; Vaughn, P.

    1999-01-01

    Mining has always had an important influence on cultures and traditions of communities around the globe and throughout history. Today, because mining legislation places heavy emphasis on environmental protection, there is great interest in having a comprehensive understanding of ancient mining and mining sites. Multi-disciplinary approaches (i.e., Pb isotopes as tracers) are being used to explore the distribution of metals in natural environments. Another successful approach is to model solution migration numerically. A proven method to simulate solution migration in natural rock salt has been applied to project through time for 10,000 years the system performance and solution concentrations surrounding a proposed nuclear waste repository. This capability is readily adaptable to simulate solution migration around mining

  5. Structural, morphological and catalytic characterization of neutral Ag salt of 12-tungstophosphoric acid: Influence of preparation conditions

    Energy Technology Data Exchange (ETDEWEB)

    Holclajtner-Antunović, Ivanka; Bajuk-Bogdanović, Danica [Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, 11158 Belgrade (Serbia); Popa, Alexandru [Institute of Chemistry Timişoara, Bl. Mihail Viteazul 24, 300223 Timişoara (Romania); Nedić Vasiljević, Bojana [Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, 11158 Belgrade (Serbia); Krstić, Jugoslav [Institute of Chemistry, Technology and Metallurgy, University of Belgrade, Njegoševa 12, 11001 Belgrade (Serbia); Mentus, Slavko [Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, 11158 Belgrade (Serbia); Uskoković-Marković, Snežana, E-mail: snezaum@pharmacy.bg.ac.rs [Faculty of Pharmacy, University of Belgrade, Vojvode Stepe 450, 11221 Belgrade (Serbia)

    2015-02-15

    Graphical abstract: - Highlights: • Preparation conditions influence to self-assembly of nanocrystallites of Ag{sub 3}PW{sub 12}O{sub 40}. • Ag{sub 3}PW{sub 12}O{sub 40} obtained by filtration is microporous, Ag{sub 3}PW{sub 12}O{sub 40} obtained by evaporation is non-porous. • Thermal properties of Ag{sub 3}PW{sub 12}O{sub 40}, H{sub 3}PW{sub 12}O{sub 40} and its soluble salts are similar. - Abstract: The objective of this study is the structural and morphological characterization of the Ag{sub 3}PW{sub 12}O{sub 40} salts (AgWPA) of 12-tungstophosphoric acid (WPA) obtained under different preparation conditions and testing of their acid catalytic activity in dehydration of ethanol. The structure, morphology and physicochemical characteristics were determined by Fourier transform infrared (FT-IR) and Raman spectroscopy, X-ray diffraction (XRD), nitrogen physisorption at −196 °C, scanning electron microscopy (SEM) and differential thermal (DTA) and thermogravimetric analysis (TGA). It is shown that the preparation process has a significant influence on the morphological properties of the obtained materials which may be explained by the supposed mechanism of the formation of nanocrystallite′s aggregates with more or less epitaxial connection. Neutral AgWPA obtained by filtration from supernatant forms porous aggregates of a symmetric dodecahedral shape, having average sizes about 2 μm. This sample shows higher specific area in comparison with the salt obtained by evaporation due to the higher micropore volume, while mesopore volumes are the same for both salts. Thus conversion of ethanol and selectivities of the main products, ethylene and diethyl ether, are almost the same and constant for both prepared salts, while their values are changed over the reaction time for the parent WPA acid.

  6. Winter climate change and coastal wetland foundation species: salt marshes vs. mangrove forests in the southeastern United States.

    Science.gov (United States)

    Osland, Michael J; Enwright, Nicholas; Day, Richard H; Doyle, Thomas W

    2013-05-01

    We live in an era of unprecedented ecological change in which ecologists and natural resource managers are increasingly challenged to anticipate and prepare for the ecological effects of future global change. In this study, we investigated the potential effect of winter climate change upon salt marsh and mangrove forest foundation species in the southeastern United States. Our research addresses the following three questions: (1) What is the relationship between winter climate and the presence and abundance of mangrove forests relative to salt marshes; (2) How vulnerable are salt marshes to winter climate change-induced mangrove forest range expansion; and (3) What is the potential future distribution and relative abundance of mangrove forests under alternative winter climate change scenarios? We developed simple winter climate-based models to predict mangrove forest distribution and relative abundance using observed winter temperature data (1970-2000) and mangrove forest and salt marsh habitat data. Our results identify winter climate thresholds for salt marsh-mangrove forest interactions and highlight coastal areas in the southeastern United States (e.g., Texas, Louisiana, and parts of Florida) where relatively small changes in the intensity and frequency of extreme winter events could cause relatively dramatic landscape-scale ecosystem structural and functional change in the form of poleward mangrove forest migration and salt marsh displacement. The ecological implications of these marsh-to-mangrove forest conversions are poorly understood, but would likely include changes for associated fish and wildlife populations and for the supply of some ecosystem goods and services. © 2012 Blackwell Publishing Ltd.

  7. Diclofenac Salts. V. Examples of Polymorphism among Diclofenac Salts with Alkyl-hydroxy Amines Studied by DSC and HSM

    Directory of Open Access Journals (Sweden)

    Adamo Fini

    2010-04-01

    Full Text Available Nine diclofenac salts prepared with alkyl-hydroxy amines were analyzed for their properties to form polymorphs by DSC and HSM techniques. Thermograms of the forms prepared from water or acetone are different in most cases, suggesting frequent examples of polymorphism among these salts. Polymorph transition can be better highlighted when analysis is carried out by thermo-microscopy, which in most cases made it possible to observe the processes of melting of the metastable form and re-crystallization of the stable one. Solubility values were qualitatively related to the crystal structure of the salts and the molecular structure of the cation.

  8. The Innovative Structure Solution for Preventing Salt Intrusion and Retaining Freshwater In Mekong Delta VietNam

    NARCIS (Netherlands)

    Hong, S.T.; Vrijling, J.K.; Stive, M.J.F.

    2013-01-01

    In the Mekong Delta Vietnam, the construction of sluices with the purpose of retaining fresh water and preventing salt water intrusion potentially plays a very important role. However, the structures constructed in small rivers according to local or traditional technology revealed many disadvantages

  9. Using of clay-salt slimes of 'Belaruskali' factory as a sorbents of radionuclide

    International Nuclear Information System (INIS)

    Maskalchuk, L.

    2010-01-01

    Document available in extended abstract form only. The effective sorbents for decrease of radionuclide migration in soil and prevention of pollution risk of soil and underground water by radionuclide, according to available practical experience on minimization of consequences of the Chernobyl NPP accident, are: clay minerals of layered structure of type 2:1, potash fertilizers for 137 Cs and potassium rocks for 90 Sr. The analysis of literary data shows, those there two base kinds of industrial waste are formed at sylvinite ore processing almost at all potassium plants of the world: - Solid halite rejects material - Liquid waste in the form of clay-salt slimes. There is about 9 % of halite waste from annual formation using in Belarus, clay-salt slimes (CSS) are not used in general and all the volume goes to slime storage. Clay-salt slimes are the waste products of potassium production being formed in the course of sylvinite ore conversion at processing plants of the Industrial centre 'Belaruskali'. Up to the present moment about 80 millions of tones of clay-salt slimes have been accumulated in Soligorsk industrial zone, and their annual formation makes up about 2.0-2.5 millions of tones. The volume of industrial waste collected in Republic of Belarus allows considering CSS as a possible source of low-cost raw material for reception of products with different functions. On the other hand by estimation of national and international experts such quantity of industrial waste, especially liquid, represents ecological danger. Taking into account this circumstance the situation with industrial waste disposal in Soligorsk industrial area of Belarus which was estimated by international experts as critical one and it needs the cardinal measures for further environment pollution prevention. There is considerable volume of liquid radioactive waste is formed at the Nuclear Power Plant operation. Modern tendencies of radioactive waste disposal are directed on

  10. Comparative Study on the Nutritional Value of Pidan and Salted Duck Egg.

    Science.gov (United States)

    Ganesan, P; Kaewmanee, T; Benjakul, S; Baharin, B S

    2014-01-01

    Pidan and salted duck eggs are of nutritional rich alternative duck egg products which are predominantly consumed in China, Thailand, South Korea and other Chinese migrated countries. Both eggs are rich in proteins, lipids, unsaturated fatty acids and minerals. A Pidan whole egg contains 13.1% of protein, 10.7% of fat, 2.25% of carbohydrate and 2.3% of ash, whereas the salted duck egg contains 14% of protein, 16.6% of fat, 4.1% of carbohydrate and 7.5% of ash. The fresh duck egg contains a range of 9.30-11.80% of protein, 11.40-13.52% of fat, 1.50-1.74% of sugar and 1.10-1.17% of ash. Proteins, lipids, and ash contents are found to be greatly enhanced during the pickling and salting process of pidan and salted duck eggs. However, the alkaline induced aggregation of pidan leads to degradation and subsequent generation of free peptides and amino acids. Very few amino acids are found to be lost during the pickling and storage. However, no such losses of amino acids are reported in salted duck eggs during the salting process of 14 d. Phospholipids and cholesterol contents are lower in pidan oil and salted duck egg yolk oil. Thus, the pidan and salted duck eggs are nutritionally rich alternatives of duck egg products which will benefit the human health during consumption.

  11. Molten salt corrosion behavior of structural materials in LiCl-KCl-UCl3 by thermogravimetric study

    Science.gov (United States)

    Rao, Ch Jagadeeswara; Ningshen, S.; Mallika, C.; Mudali, U. Kamachi

    2018-04-01

    The corrosion resistance of structural materials has been recognized as a key issue in the various unit operations such as salt purification, electrorefining, cathode processing and injection casting in the pyrochemical reprocessing of spent metallic nuclear fuels. In the present work, the corrosion behavior of the candidate materials of stainless steel (SS) 410, 2.25Cr-1Mo and 9Cr-1Mo steels was investigated in molten LiCl-KCl-UCl3 salt by thermogravimetric analysis under inert and reactive atmospheres at 500 and 600 °C, for 6 h duration. Insignificant weight gain (less than 1 mg/cm2) in the inert atmosphere and marginal weight gain (maximum 5 mg/cm2) in the reactive atmosphere were observed at both the temperatures. Chromium depletion rates and formation of Cr-rich corrosion products increased with increasing temperature of exposure in both inert and reactive atmospheres as evidenced by SEM and EDS analysis. The corrosion attack by LiCl-KCl-UCl3 molten salt, under reactive atmosphere for 6 h duration was more in the case of SS410 than 9Cr-1Mo steel followed by 2.25Cr-1Mo steel at 500 °C and the corrosion attack at 600 °C followed the order: 9Cr-1Mo steel >2.25Cr-1Mo steel > SS410. Outward diffusion of the minor alloying element, Mo was observed in 9Cr-1Mo and 2.25Cr-1Mo steels at both temperatures under reactive atmosphere. Laser Raman spectral analysis of the molten salt corrosion tested alloys under a reactive atmosphere at 500 and 600 °C for 6 h revealed the formation of unprotected Fe3O4 and α-as well as γ-Fe2O3. The results of the present study facilitate the selection of structural materials for applications in the corrosive molten salt environment at high temperatures.

  12. Structure based classification for bile salt export pump (BSEP) inhibitors using comparative structural modeling of human BSEP

    Science.gov (United States)

    Jain, Sankalp; Grandits, Melanie; Richter, Lars; Ecker, Gerhard F.

    2017-06-01

    The bile salt export pump (BSEP) actively transports conjugated monovalent bile acids from the hepatocytes into the bile. This facilitates the formation of micelles and promotes digestion and absorption of dietary fat. Inhibition of BSEP leads to decreased bile flow and accumulation of cytotoxic bile salts in the liver. A number of compounds have been identified to interact with BSEP, which results in drug-induced cholestasis or liver injury. Therefore, in silico approaches for flagging compounds as potential BSEP inhibitors would be of high value in the early stage of the drug discovery pipeline. Up to now, due to the lack of a high-resolution X-ray structure of BSEP, in silico based identification of BSEP inhibitors focused on ligand-based approaches. In this study, we provide a homology model for BSEP, developed using the corrected mouse P-glycoprotein structure (PDB ID: 4M1M). Subsequently, the model was used for docking-based classification of a set of 1212 compounds (405 BSEP inhibitors, 807 non-inhibitors). Using the scoring function ChemScore, a prediction accuracy of 81% on the training set and 73% on two external test sets could be obtained. In addition, the applicability domain of the models was assessed based on Euclidean distance. Further, analysis of the protein-ligand interaction fingerprints revealed certain functional group-amino acid residue interactions that could play a key role for ligand binding. Though ligand-based models, due to their high speed and accuracy, remain the method of choice for classification of BSEP inhibitors, structure-assisted docking models demonstrate reasonably good prediction accuracies while additionally providing information about putative protein-ligand interactions.

  13. Prestack depth migration

    International Nuclear Information System (INIS)

    Postma, R.W.

    1991-01-01

    Two lines form the southern North Sea, with known velocity inhomogeneities in the overburden, have been pre-stack depth migrated. The pre-stack depth migrations are compared with conventional processing, one with severe distortions and one with subtle distortions on the conventionally processed sections. The line with subtle distortions is also compared with post-stack depth migration. The results on both lines were very successful. Both have already influenced drilling decisions, and have caused a modification of structural interpretation in the respective areas. Wells have been drilled on each of the lines, and well tops confirm the results. In fact, conventional processing led to incorrect locations for the wells, both of which were dry holes. The depth migrated sections indicate the incorrect placement, and on one line reveals a much better drilling location. This paper reports that even though processing costs are high for pre-stack depth migration, appropriate use can save millions of dollars in dry-hole expense

  14. What Does Global Migration Network Say about Recent Changes in the World System Structure?

    Science.gov (United States)

    Zinkina, Julia; Korotayev, Andrey

    2014-01-01

    Purpose: The aim of this paper is to investigate whether the structure of the international migration system has remained stable through the recent turbulent changes in the world system. Design/methodology/approach: The methodology draws on the social network analysis framework--but with some noteworthy limitations stipulated by the specifics of…

  15. Numerical investigation of road salt impact on an urban wellfield.

    Science.gov (United States)

    Bester, M L; Frind, E O; Molson, J W; Rudolph, D L

    2006-01-01

    The impact of road salt on a wellfield in a complex glacial moraine aquifer system is studied by numerical simulation. The moraine underlies an extensive urban and industrial landscape, which draws its water supply from >20 wellfields, several of which are approaching or have exceeded the drinking water limit for chloride. The study investigates the mechanisms of road salt infiltration, storage, and transport in the subsurface and assesses the effectiveness of mitigation measures designed to reduce the impact. The three-dimensional transport model accounts for increases in salt loading, as well as growth of the urbanized area and road network over the past 50 years. The simulations, which focus on one impacted wellfield, show chloride plumes originating mainly at arterial roads and migrating through aquitard windows into the water supply aquifers. The results suggest that the aquifer system contains a large and heterogeneously distributed mass of chloride and that concentrations in the aquifer can be substantially higher than the concentrations in the well water. Future impact scenarios indicate that although the system responds rapidly to reductions in salt loading, the residual chloride mass may take decades to flush out, even if road salting were discontinued. The implications with respect to urban wellfields in typical snow-belt areas are discussed.

  16. Thermodynamics and structure of inclusion compounds of tauro- and glyco-conjugated bile salts and beta-cyclodextrin

    DEFF Research Database (Denmark)

    Holm, Rene; Shi, Wei; Andersen Hartvig, Rune

    2009-01-01

    The interaction between natural beta-cyclodextrin and bile salts common in rat, dog and man, taurocholate, tauro-beta-muricholate, taurodeoxycholate, taurochenodeoxycholate, glycocholate, glycodeoxycholate and glycochenodeoxycholate, was studied using isothermal titration calorimetry, and the str......The interaction between natural beta-cyclodextrin and bile salts common in rat, dog and man, taurocholate, tauro-beta-muricholate, taurodeoxycholate, taurochenodeoxycholate, glycocholate, glycodeoxycholate and glycochenodeoxycholate, was studied using isothermal titration calorimetry......, and the structural differences in the interaction were investigated by H-1-ROESY NMR and molecular modeling. The beta-cyclodextrin was selected based upon its frequent use in preformulation and drug formulation as oral excipients for the solubilization of drug substances with low aqueous solubility. All...

  17. Molten salt reactor type

    International Nuclear Information System (INIS)

    1977-01-01

    This document is one of the three parts of a first volume devoted to the compilations of American data on the molten salt reactor concept. Emphasize is put essentially on the fuel salt of the primary circuit inside which fission reactions occur. The reasons why the (LiF-BeF 2 -ThF 4 -UF 4 ) salt was chosen for the M.S.B.R. concept are examined; the physical, physicochemical and chemical properties of this salt are discussed with its interactions with the structural materials and its evolution in time. An important part of this volume is devoted to the continuous reprocessing of the active salt, the project designers having deemed advisable to take advantage at best from the availability of a continuous purification, in a thermal breeding. The problem of tritium formation and distribution inside the reactor is also envisaged and the fundamentals of the chemistry of the secondary coolant salt are given. The solutions proposed are: the hydrogen scavenging of the primary circuit, a reduction in metal permeability by an oxyde layer deposition on the side in contact with the vapor, and tritium absorption through an isotope exchange with the hydroxifluoroborate [fr

  18. Habitat structure modified by an invasive grass enhances inundation withstanding in a salt-marsh wolf spider

    OpenAIRE

    Pétillon, J.; Lambeets, K.; Montaigne, W.; Maelfait, J.-P.; Bonte, D.

    2010-01-01

    Vegetation and underground structures are known to influence flood avoidance and flood resistance in invertebrates. In bimonthly-flooded European salt marshes, recent invasions by the nitrophilous grass Elymus athericus strongly modified usual habitat structure, notably by the production of a deep litter layer. Consequently, invaded habitats provide more interstitial spaces that may act as a refuge during flood events. By using both controlled and field designs, we tested whether invaded habi...

  19. Internal deformation in layered Zechstein-III K-Mg salts. Structures formed by complex deformation and high contrasts in viscosity observed in drill cores.

    Science.gov (United States)

    Raith, Alexander; Urai, Janos L.

    2016-04-01

    During the evaporation of a massive salt body, alternations of interrupted and full evaporation sequences can form a complex layering of different lithologies. Viscosity contrasts of up to five orders of magnitude between these different lithologies are possible in this environment. During the late stage of an evaporation cycle potassium and magnesium (K-Mg) salts are precipitated. These K-Mg salts are of economic interest but also a known drilling hazard due to their very low viscosity. How up to 200m thick layers of these evaporites affect salt deformation at different scales is not well known. A better understanding of salt tectonics with extreme mechanical stratification is needed for better exploration and production of potassium-magnesium salts and to predict the internal structure of potential nuclear waste repositories in salt. To gain a better understanding of the internal deformation of these layers we analyzed K-Mg salt rich drill cores out of the Zechstein III-1b subunit from the Veendam Pillow 10 km southeast of Groningen, near the city Veendam in the NE Netherlands. The study area has a complex geological history with multiple tectonic phases of extension and compression forming internal deformation in the pillow but also conserving most of the original layering. Beside halite the most common minerals in the ZIII-1b are carnallite, kieserite, anhydrite and bischofite alternating in thin layers of simple composition. Seismic interpretation revealed that the internal structure of the Veendam Pillow shows areas, in which the K-Mg salt rich ZIII 1b layer is much thicker than elsewhere, as a result of salt deformation. The internal structure of the ZIII-1b on the other hand, remains unknown. The core analysis shows a strong strain concentration in the weaker Bischofite (MgCl2*6H20) and Carnallite (KMgCl3*6H20) rich layers producing tectonic breccias and highly strained layers completely overprinting the original layering. Layers formed by alternating beds

  20. Electronic Structure of the Metastable Epitaxial Rock-Salt SnSe {111} Topological Crystalline Insulator

    Directory of Open Access Journals (Sweden)

    Wencan Jin

    2017-10-01

    Full Text Available Topological crystalline insulators have been recently predicted and observed in rock-salt structure SnSe {111} thin films. Previous studies have suggested that the Se-terminated surface of this thin film with hydrogen passivation has a reduced surface energy and is thus a preferred configuration. In this paper, synchrotron-based angle-resolved photoemission spectroscopy, along with density functional theory calculations, is used to demonstrate that a rock-salt SnSe {111} thin film epitaxially grown on Bi_{2}Se_{3} has a stable Sn-terminated surface. These observations are supported by low-energy electron diffraction (LEED intensity-voltage measurements and dynamical LEED calculations, which further show that the Sn-terminated SnSe {111} thin film has undergone a surface structural relaxation of the interlayer spacing between the Sn and Se atomic planes. In sharp contrast to the Se-terminated counterpart, the observed Dirac surface state in the Sn-terminated SnSe {111} thin film is shown to yield a high Fermi velocity, 0.50×10^{6}  m/s, which suggests a potential mechanism of engineering the Dirac surface state of topological materials by tuning the surface configuration.

  1. Assessing the Potential for Inland Migration of a Northeastern Salt Marsh

    Science.gov (United States)

    Farron, S.; FitzGerald, D.; Hughes, Z. J.

    2017-12-01

    It is often assumed that as sea level rises, salt marshes will expand inland. If the slope of the upland is relatively flat and sufficient sediment is available, marshes should be able to spread horizontally and grow vertically in order to maintain their areal extent. However, in cases where marshes are backed by steeper slopes, or sediment supply is limited, rising sea level will produce minimal gains along the landward edge insufficient to offset potential losses along the seaward edge. This study uses future sea level rise scenarios to project areal losses for the Great Marsh in Massachusetts, the largest continuous salt marsh in New England. Land area covered by salt marsh is defined by surface elevation. Annual sediment input to the system is estimated based on the areal extent of high and low marsh, historical accretion rates for each, and known organic/inorganic ratios. Unlike other studies, sediment availability is considered to be finite, and future accretion rates are limited based on the assumption that the system is presently receiving the maximum sediment input available. The Great Marsh is dominated by high marsh; as sea level rises, it will convert to low marsh, vastly altering the ecological and sedimentological dynamics of the system. If it is assumed that former high marsh areas will build vertically at the increased rate associated with low marsh, then much of the total marsh area will be maintained. However, this may be an unrealistic assumption due to the low levels of suspended sediment within the Great Marsh system. Modeling the evolution of the Great Marsh by assuming that the current accretion rate is the maximum possible for this system reveals much greater losses than models assuming an unlimited sediment supply would predict (17% less marsh by 2115). In addition, uplands surrounding the Great Marsh have been shaped by glaciation, leaving numerous drumlins and other glacial landforms. Compared to the flat backbarrier, the surrounding

  2. Salt dissolution and collapse at the Wink Sink in West Texas

    International Nuclear Information System (INIS)

    Johnson, K.S.

    1986-06-01

    The Wink Sink, in Winkler County, Texas, is a collapse feature that formed in June 1980 when an underground dissolution cavity migrated upward by successive roof failures until it breached the land surface. The original cavity developed in the Permian Salado Formation salt beds more than 1300 feet below ground level. Natural dissolution of salt occurred in the vicinity of the Wink Sink in several episodes that began as early as Salado time and recurred in later Permian, Triassic, and Cenozoic time. Although natural dissolution cavity and resultant collapse were influenced by petroleum production activity in the immediate area. Drilling, completion, and plugging procedures used on an abandoned oil well at the site of the sink appear to have created a conduit that enabled water to circulate down the borehole and dissolve the salt. When the dissolution cavity became large enough, the roof failed and the overlying rocks collapsed into the cavity. Similar collapse features exist where underground salt beds have been intentionally dissolved during solution mining or accidentally dissolved as a result of petroleum production activities

  3. Salt composition of groundwater and reclaimed solonetzes in the Baraba Lowland

    Science.gov (United States)

    Semendyaeva, N. V.; Elizarov, N. V.

    2017-10-01

    Solonetzes of experimental trials established in 1981 and 1986 in the Baraba Lowland were examined. It was found that gypsum-based ameliorants improve the soil and lead to a decrease in the content of soluble salts in the soil profile. Exchange processes between cations of the soil adsorption complex and calcium of gypsum were particularly intensive in the first years after gypsum application. This resulted in a sharp rise in the content of soluble salts that migrated down the soil profile to the groundwater. In the following years, the reclaimed solonetzes were desalinized under the conditions of relatively stable groundwater level. On the 30th year after single gypsum application, the groundwater level sharply rose (to 50 cm), and the soil was subjected to the secondary salinization; the contents of bicarbonates, carbonates, and sodium in the soils increased. Spring leaching caused some desalinization, but the content of soluble salts in the upper soil meter increased again in the fall. A close correlation between the salt compositions of the groundwater and the reclaimed solonetzes was revealed.

  4. Effects of nanoparticle heating on the structure of a concentrated aqueous salt solution.

    Science.gov (United States)

    Sindt, Julien O; Alexander, Andrew J; Camp, Philip J

    2017-12-07

    The effects of a rapidly heated nanoparticle on the structure of a concentrated aqueous salt solution are studied using molecular dynamics simulations. A diamond-like nanoparticle of radius 20 Å is immersed in a sodium-chloride solution at 20% above the experimental saturation concentration and equilibrated at T = 293 K and P = 1 atm. The nanoparticle is then rapidly heated to several thousand degrees Kelvin, and the system is held under isobaric-isoenthalpic conditions. It is observed that after 2-3 ns, the salt ions are depleted far more than water molecules from a proximal zone 15-25 Å from the nanoparticle surface. This leads to a transient reduction in molality in the proximal zone and an increase in ion clustering in the distal zone. At longer times, ions begin to diffuse back into the proximal zone. It is speculated that the formation of proximal and distal zones, and the increase in ion clustering, plays a role in the mechanism of nonphotochemical laser-induced nucleation.

  5. Effects of nanoparticle heating on the structure of a concentrated aqueous salt solution

    Science.gov (United States)

    Sindt, Julien O.; Alexander, Andrew J.; Camp, Philip J.

    2017-12-01

    The effects of a rapidly heated nanoparticle on the structure of a concentrated aqueous salt solution are studied using molecular dynamics simulations. A diamond-like nanoparticle of radius 20 Å is immersed in a sodium-chloride solution at 20% above the experimental saturation concentration and equilibrated at T = 293 K and P = 1 atm. The nanoparticle is then rapidly heated to several thousand degrees Kelvin, and the system is held under isobaric-isoenthalpic conditions. It is observed that after 2-3 ns, the salt ions are depleted far more than water molecules from a proximal zone 15-25 Å from the nanoparticle surface. This leads to a transient reduction in molality in the proximal zone and an increase in ion clustering in the distal zone. At longer times, ions begin to diffuse back into the proximal zone. It is speculated that the formation of proximal and distal zones, and the increase in ion clustering, plays a role in the mechanism of nonphotochemical laser-induced nucleation.

  6. Salinity Alters the Polyisoprenoid Alcohol Content and Composition of Both Salt-Secreting and Non–Salt-Secreting Mangrove Seedlings

    Directory of Open Access Journals (Sweden)

    Mohammad Basyuni

    2017-10-01

    Full Text Available The effects of salinity on the polyisoprenoid alcohol content and composition of the salt-secreting mangrove species Avicennia marina and Sonneratia alba and the non–salt-secreting species Bruguiera gymnorrhiza and Kandelia obovata were studied. The seedlings of mangroves were grown for 5 months under 0% and 3% salt concentrations. The occurrence, content, and distribution of four mangrove seedlings were analyzed by two-dimensional thin layer chromatography. The structural groups of the polyprenols and dolichols in the leaves and roots were classified into two types (I and II. In type I, dolichols predominated over polyprenols (more than 90%, whereas in type II, the occurrence of both polyprenols and dolichols was observed. Polyprenols were not detected in the leaves of A. marina and B. gymnorrhiza under 0% salt (control, but were detected in small amounts in K. obovata leaves; however, significant amounts were found in the 3% salinity group. This finding in A. marina, B. gymnorrhiza, and K. obovata leaves implies a change to the structural group: under 0% salt concentrations, the groups are classified as type I, but become type II under 3% salt concentrations. The occurrence of ficaprenol (C50–55 was found only in the leaves of the non–salt-secreting species B. gymnorrhiza and K. obovata under 3% salinity and not in the salt-secreting species A. marina or S. alba. It is noteworthy that the polyisoprenoid type in the roots of the four species showed no change under salinity; the two salt-secreting species A. marina and S. alba contained type I under 0% and 3% salt concentrations. On the other hand, type II polyisoprenoids were identified in the non–salt-secreting species B. gymnorrhiza and K. obovata under 0% and 3% salinity conditions. This finding suggested that polyisoprenoids play a protective role against salinity in the mangrove leaves of both salt-secreting and non–salt-secreting species.

  7. Ultrasonic testing of a sealing construction made of salt concrete in an underground disposal facility for radioactive waste

    Energy Technology Data Exchange (ETDEWEB)

    Krause, Martin; Effner, Ute Antonie; Milmann, Boris; Voelker, Christoph; Wiggenhauser, Herbert [Federal Institute for Materials Research and Testing (BAM), Berlin (Germany); Mauke, Ralf [The Federal Office for Radiation Protection, Salzgitter (Germany)

    2015-07-01

    For the closure of radioactive waste disposal facilities engineered barriers- so called ''drift seals'' are used. The purpose of these barriers is to constrain the possible infiltration of brine and to prevent the migration of radionuclides into the biosphere. In a rock salt mine a large scale in-situ experiment of a sealing construction made of salt concrete was set up to prove the technical feasibility and operability of such barriers. In order to investigate the integrity of this structure, non-destructive ultrasonic measurements were carried out. Therefore two different methods were applied at the front side of the test-barrier: 1 Reflection measurements from boreholes 2 Ultrasonic imaging by means of scanning ultrasonic echo methods This extended abstract is a short version of an article to be published in a special edition of ASCE Journal that will briefly describe the sealing construction, the application of the non-destructive ultrasonic measurement methods and their adaptation to the onsite conditions -as well as parts of the obtained results. From this a concept for the systematic investigation of possible contribution of ultrasonic methods for quality assurance of sealing structures may be deduced.

  8. Analysis of the temperature field around salt diapirs

    DEFF Research Database (Denmark)

    Jensen, Peter Klint

    1990-01-01

    heat flux should be higher over 3D structures. On the other hand the areal extent of the temperature anomaly around the salt structures is less in the 3D case. Calculation examples indicate that low temperature geothermal energy exploitation of the formations around the top of a salt diapir can...

  9. HRTEM and neutron diffraction study of LixMo5O17: From the ribbon (x=5) structure to the rock salt (x=12) structure

    International Nuclear Information System (INIS)

    Lebedev, O.I.; Caignaert, V.; Raveau, B.; Pop, N.; Gozzo, F.; Van Tendeloo, G.; Pralong, V.

    2011-01-01

    Structure determination of the fully intercalated phase Li 12 Mo 5 O 17 and of the deintercalated oxide Li 5 Mo 5 O 17 has been carried out by electron microscopy and neutron powder diffraction. The reversible topotactic transformation between the ordered rock salt structure of the former and the ribbon structure of the latter (closely related to that of Li 4 Mo 5 O 17 ) is explained on the following basis: both structures can be described as strips built up as an assembly of infinite ribbons of MoO 6 octahedra that are five octahedra thick, and that differ by slight displacements of the octahedral ribbons. We show that the electrochemical behavior of the Li x Mo 5 O 17 system is based on two sorts of Li + sites; those that are located within the strips between the ribbons, and those that are located at the border of the strips. The high rate of Li intercalation in this oxide and its reversibility are discussed in terms of its peculiar structure. -- Graphical abstract: Structure determination of the fully intercalated phase Li 12 Mo 5 O 17 and of the deintercalated oxide Li 5 Mo 5 O 17 has been carried out by electron microscopy and neutron powder diffraction. The reversible topotactic transformation between the ordered rock salt structure of the former and the ribbon structure of the latter is explained on the following basis: both structures can be described as strips built up as an assembly of infinite ribbons of MoO 6 octahedra that are five octahedra thick, and that differ by slight displacements of the octahedral ribbons. We show that the electrochemical behavior of the Li x Mo 5 O 17 system is based on two sorts of Li + sites; those that are located within the strips between the ribbons, and those that are located at the border of the strips. The high rate of Li intercalation in this oxide and its reversibility are discussed in terms of its peculiar structure. Research highlights: → Electron microscopy and neutron powder diffraction structure determination

  10. [Community structure and diversity of culturable moderate halophilic bacteria isolated from Qrhan salt lake on Qinghai-Tibet Plateau].

    Science.gov (United States)

    Shen, Shuo

    2017-04-04

    I studied the community structure and diversity of culturable moderate halophilic bacteria isolated from Qrhan Salt Lake. I isolated and cultured the moderate halophilic bacteria on different selective media. After the 16S rRNA gene sequences was amplified and measured, I constructed the phylogenic tree, analyzed the community structure and calculated the diversity indexes according to the 16S rRNA gene information. A total of 421 moderate halophilic bacteria were isolated from water and mud samples in Qrhan Salt Lake. The 16S rRNA gene information showed that 4 potential novel species belonged to the family Bacillaceae. Eighty-three model strains belonged to 3 phylurms 6 families 16 genus. Among them, Bacillus sp., Oceanobacillus sp. and Halomonas sp. were dominant species. Diversity analysis showed that the diversity of strains isolated from water sample was higher than that from mud sample, but the dominance degree of strains isolated from mud sample was higher than that from water sample. The genetic diversity of moderate halophilic bacteria isolated from Qrhan Salt Lake was abundant. Also, there were dominant and novel species of culturable moderate halophilic bacteria in this lake.

  11. Salicylic Acid Alleviates the Adverse Effects of Salt Stress on Dianthus superbus (Caryophyllaceae) by Activating Photosynthesis, Protecting Morphological Structure, and Enhancing the Antioxidant System

    Science.gov (United States)

    Ma, Xiaohua; Zheng, Jian; Zhang, Xule; Hu, Qingdi; Qian, Renjuan

    2017-01-01

    Salt stress critically affects the physiological processes and morphological structure of plants, resulting in reduced plant growth. Salicylic acid (SA) is an important signal molecule that mitigates the adverse effects of salt stress on plants. Large pink Dianthus superbus L. (Caryophyllaceae) usually exhibit salt-tolerant traits under natural conditions. To further clarify the salt-tolerance level of D. superbus and the regulating mechanism of exogenous SA on the growth of D. superbus under different salt stresses, we conducted a pot experiment to examine the biomass, photosynthetic parameters, stomatal structure, chloroplast ultrastructure, reactive oxygen species (ROS) concentrations, and antioxidant activities of D. superbus young shoots under 0.3, 0.6, and 0.9% NaCl conditions, with and without 0.5 mM SA. D. superbus exhibited reduced growth rate, decreased net photosynthetic rate (Pn), increased relative electric conductivity (REC) and malondialdehyde (MDA) contents, and poorly developed stomata and chloroplasts under 0.6 and 0.9% salt stress. However, exogenously SA effectively improved the growth, photosynthesis, antioxidant enzyme activity, and stoma and chloroplast development of D. superbus. However, when the plants were grown under severe salt stress (0.9% NaCl condition), there was no significant difference in the plant growth and physiological responses between SA-treated and non-SA-treated plants. Therefore, our research suggests that exogenous SA can effectively counteract the adverse effect of moderate salt stress on D. superbus growth and development. PMID:28484476

  12. Salicylic Acid Alleviates the Adverse Effects of Salt Stress on Dianthus superbus (Caryophyllaceae by Activating Photosynthesis, Protecting Morphological Structure, and Enhancing the Antioxidant System

    Directory of Open Access Journals (Sweden)

    Xiaohua Ma

    2017-04-01

    Full Text Available Salt stress critically affects the physiological processes and morphological structure of plants, resulting in reduced plant growth. Salicylic acid (SA is an important signal molecule that mitigates the adverse effects of salt stress on plants. Large pink Dianthus superbus L. (Caryophyllaceae usually exhibit salt-tolerant traits under natural conditions. To further clarify the salt-tolerance level of D. superbus and the regulating mechanism of exogenous SA on the growth of D. superbus under different salt stresses, we conducted a pot experiment to examine the biomass, photosynthetic parameters, stomatal structure, chloroplast ultrastructure, reactive oxygen species (ROS concentrations, and antioxidant activities of D. superbus young shoots under 0.3, 0.6, and 0.9% NaCl conditions, with and without 0.5 mM SA. D. superbus exhibited reduced growth rate, decreased net photosynthetic rate (Pn, increased relative electric conductivity (REC and malondialdehyde (MDA contents, and poorly developed stomata and chloroplasts under 0.6 and 0.9% salt stress. However, exogenously SA effectively improved the growth, photosynthesis, antioxidant enzyme activity, and stoma and chloroplast development of D. superbus. However, when the plants were grown under severe salt stress (0.9% NaCl condition, there was no significant difference in the plant growth and physiological responses between SA-treated and non-SA-treated plants. Therefore, our research suggests that exogenous SA can effectively counteract the adverse effect of moderate salt stress on D. superbus growth and development.

  13. Protonation of inorganic 5-Fluorocytosine salts

    Science.gov (United States)

    Souza, Matheus S.; da Silva, Cecília C. P.; Almeida, Leonardo R.; Diniz, Luan F.; Andrade, Marcelo B.; Ellena, Javier

    2018-06-01

    5-Fluorocytosine (5-FC) has been widely used for the treatment of fungal infections and recently was found to exert an extraordinary antineoplastic activity in gene directed prodrug therapy. However, despite of its intense use, 5-FC exhibits tabletability issues due its physical instability in humid environments, leading to transition from the anhydrous to monohydrate phase. By considering that salt formation is an interesting strategy to overcome this problem, in this paper crystal engineering approach was applied to the supramolecular synthesis of new 5-FC salts with sulfuric, hydrobromic and methanesulfonic inorganic acids. A total of four structures were obtained, namely 5-FC sulfate monohydrate (1:1:1), 5-FC hydrogen sulfate (1:1), 5-FC mesylate (1:1) and 5-FC hydrobromide (1:1), the last one being a polymorphic form of a structure already reported in the literature. These novel salts were structurally characterized by single crystal X-ray diffraction and its supramolecular organization were analyses by Hirshfeld surface analysis. The vibrational behavior was evaluated by Raman spectroscopy and it was found to be consistent with the crystal structures.

  14. De‐blending reverse‐time migration

    KAUST Repository

    Fei, Tong W.; Luo, Yi; Schuster, Gerard T.

    2010-01-01

    Reverse‐time migration (RTM), based on the full two‐way wave equation, has gained interest and become a popular imaging tool for complex structures in the last few years. The method is well‐known for its ability to better image the steeply dipping and overturned structures than the migration methods based on the one‐way wave equation extrapolation. However, the RTM image often contains low frequency and back‐scattering noise, and the imaging quality is sensitive to the migration velocity. In order to improve the RTM imaging quality and make the RTM image less sensitive to the velocity model, we developed an RTM de‐blending technique which separates upgoing and downgoing source and receiver wavefields, and then use them to construct final RTM images. Test results show that decomposed images obtained from only the downgoing source and receiver wavefields are less sensitive to velocity. It removes unwanted noise and migration artifacts from conventional RTM, and the imaging quality is greatly improved compared with a conventional RTM image.

  15. De‐blending reverse‐time migration

    KAUST Repository

    Fei, Tong W.

    2010-10-17

    Reverse‐time migration (RTM), based on the full two‐way wave equation, has gained interest and become a popular imaging tool for complex structures in the last few years. The method is well‐known for its ability to better image the steeply dipping and overturned structures than the migration methods based on the one‐way wave equation extrapolation. However, the RTM image often contains low frequency and back‐scattering noise, and the imaging quality is sensitive to the migration velocity. In order to improve the RTM imaging quality and make the RTM image less sensitive to the velocity model, we developed an RTM de‐blending technique which separates upgoing and downgoing source and receiver wavefields, and then use them to construct final RTM images. Test results show that decomposed images obtained from only the downgoing source and receiver wavefields are less sensitive to velocity. It removes unwanted noise and migration artifacts from conventional RTM, and the imaging quality is greatly improved compared with a conventional RTM image.

  16. Structural-equation models of migration: an example from the Upper Midwest USA.

    Science.gov (United States)

    Cadwallader, M

    1985-01-01

    "To date, most migration models have been specified in terms of a single equation, whereby a set of regional characteristics are used to predict migration rates for various kinds of spatial units. These models are inadequate in at least two respects. First, they omit any causal links between the explanatory variables, thus ignoring indirect effects between these variables and migration. Second, they ignore the possibility of reciprocal causation, or feedback effects, between migration and the explanatory variables...." The author uses data for State Economic Areas to construct a path model and simultaneous-equation model to identify both indirect and feedback effects on migration in the Upper Midwestern United States. "On the basis of the path model, it is suggested that the direct effects of many variables on migration are at least partially offset by the indirect effects, whereas the simultaneous-equation model emphasizes the reciprocal relationship between income and migration." excerpt

  17. Structural Characterization of Emeraldine-Salt Polyaniline/Gold Nanoparticles Complexes

    Directory of Open Access Journals (Sweden)

    E. A. Sanches

    2011-01-01

    Full Text Available Gold nanoparticles (Au NPs stabilized with polyamidoamine dendrimers (Au-PAMAM or sodium citrate (Au-CITRATE were synthesized and complexed with polyaniline emeraldine-salt form (ES-PANI. The complexes were characterized using structural and morphological techniques, including X-Ray Diffraction (XRD, Scanning Electron Microscopy (SEM, Zeta Potential analyses, and Fourier-Transformed Infrared spectroscopy (FTIR. When the Au-CITRATE NPs are added to the polymeric solution, the formation of a precipitate is clearly observed. The precipitate exhibited a different morphology from that found for ES-PANI and Au-CITRATE NPs, suggesting the formation of ES-PANI coating over the surface of Au-CITRATE NPs. On the other hand, when the Au-PAMAM NPs are incorporated into the ES-PANI solution, none interaction was observed, probably due to the repulsive electrostatic interactions, being the organization of the ES-PANI chains unaffected by the presence of the Au-PAMAM NPs.

  18. Production of specific-structured lipids by enzymatic interesterification: elucidation of acyl migration by response surface design

    DEFF Research Database (Denmark)

    Xu, Xuebing; Skands, Anja; Høy, Carl-Erik

    1998-01-01

    Production of specific-structured lipids (SSL) by lipase-catalyzed interesterification has been attracting more and more attention recently. However, it was found that acyl migration occurs during the reaction and causes the production of by-products. In this paper, the elucidation of acyl...

  19. Design of the algorithm of photons migration in the multilayer skin structure

    Science.gov (United States)

    Bulykina, Anastasiia B.; Ryzhova, Victoria A.; Korotaev, Valery V.; Samokhin, Nikita Y.

    2017-06-01

    Design of approaches and methods of the oncological diseases diagnostics has special significance. It allows determining any kind of tumors at early stages. The development of optical and laser technologies provided increase of a number of methods allowing making diagnostic studies of oncological diseases. A promising area of biomedical diagnostics is the development of automated nondestructive testing systems for the study of the skin polarizing properties based on backscattered radiation detection. Specification of the examined tissue polarizing properties allows studying of structural properties change influenced by various pathologies. Consequently, measurement and analysis of the polarizing properties of the scattered optical radiation for the development of methods for diagnosis and imaging of skin in vivo appear relevant. The purpose of this research is to design the algorithm of photons migration in the multilayer skin structure. In this research, the algorithm of photons migration in the multilayer skin structure was designed. It is based on the use of the Monte Carlo method. Implemented Monte Carlo method appears as a tracking the paths of photons experiencing random discrete direction changes before they are released from the analyzed area or decrease their intensity to negligible levels. Modeling algorithm consists of the medium and the source characteristics generation, a photon generating considering spatial coordinates of the polar and azimuthal angles, the photon weight reduction calculating due to specular and diffuse reflection, the photon mean free path definition, the photon motion direction angle definition as a result of random scattering with a Henyey-Greenstein phase function, the medium's absorption calculation. Biological tissue is modeled as a homogeneous scattering sheet characterized by absorption, a scattering and anisotropy coefficients.

  20. Free energy landscape of a minimalist salt bridge model.

    Science.gov (United States)

    Li, Xubin; Lv, Chao; Corbett, Karen M; Zheng, Lianqing; Wu, Dongsheng; Yang, Wei

    2016-01-01

    Salt bridges are essential to protein stability and dynamics. Despite the importance, there has been scarce of detailed discussion on how salt bridge partners interact with each other in distinct solvent exposed environments. In this study, employing a recent generalized orthogonal space tempering (gOST) method, we enabled efficient molecular dynamics simulation of repetitive breaking and reforming of salt bridge structures within a minimalist salt-bridge model, the Asp-Arg dipeptide and thereby were able to map its detailed free energy landscape in aqueous solution. Free energy surface analysis shows that although individually-solvated states are more favorable, salt-bridge states still occupy a noticeable portion of the overall population. Notably, the competing forces, e.g. intercharge attractions that drive the formation of salt bridges and solvation forces that pull the charged groups away from each other, are energetically comparable. As the result, the salt bridge stability is highly tunable by local environments; for instance when local water molecules are perturbed to interact more strongly with each other, the population of the salt-bridge states is likely to increase. Our results reveal the critical role of local solvent structures in modulating salt-bridge partner interactions and imply the importance of water fluctuations on conformational dynamics that involves solvent accessible salt bridge formations. © 2015 The Protein Society.

  1. Modeling of brine migration in halite

    International Nuclear Information System (INIS)

    Cheung, H.; Fuller, M.E.; Gaffney, E.S.

    1979-01-01

    When canisters containing radwastes are emplaced in a repository the heat produced by the decaying radwaste will cause moderate thermal gradients to develop which will cause the brine present in a halite medium (salt deposits) to accumulate around the canister. Four different models of the migration process have been reviewed to determine their suitability as a working model. One model predicts that inclusions smaller than 0.1 mm dimension probably will not migrate. The other models do not consider size as a factor. Thermal diffusion (Soret effect) is considered insignificant in three models, while in the fourth model it is added to the concentration diffusion term. The following conclusions can be made: Temperature is the most significant parameter in all models and must be known as a function of time, and distance from the canister. All four models predict about the same migration velocity for it is a given set of conditions; for 100 0 C and 1 0 C/cm thermal gradient, it is 3.0, 4.8, 5.6 and 6.4 mm/y. Diffusion of ions through the brine inclusions is the rate controlling mechanism. The difference between the thermal gradients in the liquid and in the solid should always be considered and is a function of droplet shape. The model based upon work by Nernst is easiest to use, but it predicts the lowest migration rate. The maximum volume of pure brine accumulated at the canister surface would be less than 20-40 liters in 50 years, for a canister initial thermal power of 3.5 kW.Bitterns would migrate proportionately less volume. A computer code, BRINE, was developed to make these calculations by means of any of the four models

  2. Geosphere migration studies as support for the comparison of candidate sites for disposal of radioactive waste in rock-salt

    International Nuclear Information System (INIS)

    Glasbergen, P.; Hassanizadeh, S.M.; Noordijk, H.; Sauter, F.

    1988-01-01

    The Dutch research program on the geological disposal of radioactive waste was designed to supply a basis for the selection of combinations of three factors, i.e., type of rock-salt formation, site, and disposal technique, satisfying radiological standards and other criteria for final disposal. The potential sites have been grouped according to the type of rock-salt formation (e.g. bedded salt and salt domes) and two classes of depth below the surface of the ground. Values for geohydrological parameters were obtained by extrapolation of data from existing boreholes and analysis of the sedimentary environment. A three-dimensional model of groundwater flow and contaminant transport, called METROPOL, has been developed. To investigate the effect of high salinity on nuclide transport properly, a theoretical experimental study was carried out. Use of a thermodynamic approach showed that terms related to salt mass fraction have to be added to Darcy's and Fick's laws. An experimental study to investigate effects of these modifications is in progress. 8 refs.; 8 figs.; 1 table

  3. Crystal structure of indoline alkaloids kopsinilam, kopsinine, and the salts of the latter

    DEFF Research Database (Denmark)

    Adizov, Sh. M.; Tashkhodzhaev, B.; Kunafiev, R. Zh.

    2016-01-01

    N1 in the bases and the salts. Tetrahedral hybridization of the atom N1 in indoline alkaloids favors the formation of their double salts, what is unlikely for indole and indolinine alkaloids. In the halogen double salts there is an intramolecular Н bond between one of the protons of the NH2 group......Indoline alkaloids kopsinilam and kopsinine extracted from the plant Vinca erecta have been studied by X-ray crystallography; mono and double salts of the latter alkaloid also have been examined. Experimentally determined positions of Н atoms suggest sp3 hybridization of the indoline nitrogen atom...... and the oxygen of the methoxycarbonyl group, that is absent in the mono salts and pure bases....

  4. Evolution of cooperation among game players with non-uniform migration scopes

    International Nuclear Information System (INIS)

    Zhang, Chunyan; Zhang, Jianlei; Xie, Guangming

    2014-01-01

    In social dilemmas, cooperation among randomly interacting individuals is often hard to achieve. The situation changes if migration takes place, where game structure jointly evolves with the migration from adverse neighborhoods. Here we introduce a framework combining migration with the individual heterogeneity of migration scopes. When faced with a gloomy outlook, some players prefer vacant sites within their adjacent neighborhoods, while others may migrate within the whole network, provided the sites are empty. Thus, we can make a thorough inquiry of the sustainability of cooperation in a spatially distributed population divided by these two groups, and all possible mixtures between them. Our main result is that small-scope migration and suitable population density can gear up high cooperation levels in the midst of dense populations structured by scale-free networks, while large-scope migration and sparsity favor the cooperator clustering among lattice-structured populations. In this sense, the conditions for the emergence of cooperation are prevailingly created by the spatial reciprocity, and migration also has enough potential to help cooperation to prevail in suitable combination of game parameters in dynamics (e.g., population density, the type of interaction structure and also the migration scope)

  5. Structural violence and the state: HIV and labour migration from Pakistan to the Persian Gulf.

    Science.gov (United States)

    Qureshi, Ayaz

    2013-01-01

    This paper examines the biopolitics of HIV and labour migration from Pakistan (a country classified by UNAIDS as at 'high risk' of a generalised epidemic) to the countries of the Gulf Cooperation Council (GCC). The remittances by the labour migrants in the Gulf are an invaluable source of foreign exchange for Pakistan and a large number of households are entirely dependent upon them. At the same time, the National AIDS Control Programme regards Gulf migrants as a key risk factor for an HIV epidemic. The majority of HIV positive people in clinics comprise Gulf returnee migrants and their family members. This paper suggests that in the process of migrating, prospective migrants are subjected to structural violence that increases their HIV vulnerabilities. In this process, they are subjected to regimes of medical inspection, reduced to their certifiable labour power, inscribed with nationalist ideologies identifying HIV as a disease that strikes 'the other', and exposed to exploitation that increases their vulnerabilities. After migration, they are made to undergo compulsory periodic medical examinations in the GCC and, if found to be HIV positive, they are forcibly deported without papers, proper diagnosis or healthcare - only to return as 'failed subjects'. Taking a disaggregated view of the state, the paper argues that, in order to be effective, debates on structural violence and the HIV epidemic must make explicit the role of the state in producing migrants' vulnerabilities.

  6. Synthesis, growth, structural, optical and thermal properties of a new organic salt crystal: 3-nitroanilinium trichloroacetate

    Science.gov (United States)

    Selvakumar, E.; Chandramohan, A.; Anandha Babu, G.; Ramasamy, P.

    2014-09-01

    A new organic non-linear optical salt 3-nitroanilinium trichloroacetate has been synthesized and single crystals grown by slow solvent evaporation solution growth technique at room temperature using methanol as the solvent. The 1H and 13C Nuclear magnetic resonance spectra were recorded to establish the molecular structure of the title salt. The crystal structure of the title crystal has been determined by single crystal X-ray diffraction analysis and it belongs to monoclinic crystal system with non-centrosymmetric space group P21. Fourier transform infrared spectral study has been carried out to confirm the presence of various functional groups. The optical transmittance spectrum was recorded in the range 200-2500 nm, to find the optical transmittance window and lower cut off wavelength. The thermo gravimetric and differential thermal analyses were carried out to establish the thermal stability of the title crystal. The second harmonic generation in the title crystal was confirmed by the modified Kurtz-Perry powder test employing the Nd: YAG laser as the source for infrared radiation.

  7. Separation of calcium isotopes by counter-current electromigration in molten salts (1962); Separation des isotopes du calcium par electro-migration a contre-courant en sels fondus (1962)

    Energy Technology Data Exchange (ETDEWEB)

    Menes, F; Dirian, G; Roth, E [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1962-07-01

    The method of counter-current electromigration in molten salts has been applied to calcium bromide with an alkali metal bromide added to the cathode compartment. Enrichments on calcium-46 greater than a factor of two were obtained at the anode. The mass effect was found to be about 0.06. An estimation of the cost of energy for a process based on this method has been made. (authors) [French] La methode d'electro-migration a contre-courant en sels fondus a ete appliquee au bromure de calcium additionne dans le compartiment cathodique d'un bromure alcalin. On a pu ainsi obtenir avec surete des enrichissements anodiques superieurs a 2 sur l'isotope 46, determiner l'effet de masse (environ 0,06) et faire une estimation sommaire du cout energetique d'un procede base sur cette methode. (auteurs)

  8. Stratigraphic response of salt marshes to slow rates of sea-level change

    Science.gov (United States)

    Daly, J.; Bell, T.

    2006-12-01

    Conventional models of salt-marsh development show an idealized spatial relationship between salt-marsh floral and foraminiferal zones, where the landward margin of the marsh gradually migrates inland in response to sea-level rise. This model predicts that transgression will result in persistent and possibly expanded salt marshes at the surface, depending on a variety of factors including sediment supply, hydrologic conditions, tidal range, and rate of sea-level rise. However, in areas with abundant sediment supply and slow rates of sea- level rise, the extent of back-barrier salt marshes may decline over time as the barrier-spits mature. Sea level around the northeast coast of Newfoundland is rising at a very slow rate during the late Holocene (flora. These transitions are interpreted to reflect the progradation of the spit, decreased tidal exchange in the back-barrier, and increased influence of freshwater streams discharging into the back-barrier setting. Decreased marine influence on the back-barrier environment leads to a floral and faunal shift associated with a regressive stratigraphy in an area experiencing sea-level rise. For studies of Holocene sea-level change requiring salt-marsh stratigraphic records, it is necessary to account for changing micro-environments to locate sites appropriate for study; salt marshes may play an important role in defining the record, but may not exist at the surface to guide investigation.

  9. Globalization of international migration: Social challenges and policy implication

    Directory of Open Access Journals (Sweden)

    I A Aleshkovski

    2017-12-01

    Full Text Available In the second half of the XX century, the humankind witnessed the insurmountable and irreversible power of globalization processes, which influence all spheres of social life and establish a global system of interdependency between countries and nations. Globalization within impetuous changes in global political, social and economic systems has determined dramatic shifts in the international migration processes that lead to the new stage of migration history. In nowadays globalized world, international migration has become a reality for almost all corners of the globe. The author considers features of the recent trends of international migration: the unprecedented growth of the international migration flows; the widening geography of international migration that involves nearly all countries of the world; qualitative changes in the structure of international migration flows; the key role of economic migration; the permanent growth and structural intricateness of irregular migration; the increasing scale and geographical widening of forced migration; the growing importance of international migration for the demographic development of the world, countries of both origin and destination. All these trends combined prove that the international migration patterns have become more complex. The author analyzes the legal framework of the international migration processes, and gives recommendations on the ways to improve the control and regulation of migration processes. Specific issues related to the social challenges of international migration are also discussed in the article.

  10. The Transformative Forces of Migration: Refugees and the Re-Configuration of Migration Societies

    Directory of Open Access Journals (Sweden)

    Ulrike Hamann

    2018-03-01

    Full Text Available In this thematic issue, we attempt to show how migrations transform societies at the local and micro level by focusing on how migrants and refugees navigate within different migration regimes. We pay particular attention to the specific formation of the migration regimes that these countries adopt, which structure the conditions of the economic, racialised, gendered, and sexualized violence and exploitation during migration processes. This interactive process of social transformation shapes individual experiences while also being shaped by them. We aim to contribute to the most recent and challenging question of what kind of political and social changes can be observed and how to frame these changes theoretically if we look at local levels while focusing on struggles for recognition, rights, and urban space. We bring in a cross-country comparative perspective, ranging from Canada, Chile, Spain, Sweden, Turkey, and to Germany in order to lay out similarities and differences in each case, within which our authors analyse these transformative forces of migration.

  11. Salt geologic evaluation of the impact of cryogenic fissures and halokinetic deformation processes on the integrity of the geological barrier of the salt dome Gorleben

    International Nuclear Information System (INIS)

    Hammer, Joerg; Fleig, Stephanie; Mingerzahn, Gerhard

    2012-07-01

    In several salt domes of the area close to Hannover fissures were observed that might be caused by thermally induced fissure formation due to cold periods (cryogenic fissures). Comprehensive substantial-structural analyses are performed as an example for the salt dome Bokeloh with respect to genesis and transferability to the salt dome Gorleben. Based on recent structure-geological, mineralogical-geochemical and micro-paleontological studies and thermo-mechanical modeling a solely thermally induced fissure formation due to cold periods is unlikely for the salt dome Bokeloh. There is a direct relation between the genesis of the salt dome Bokeloh, its regional tectonic site and the fissure formation. Due to the completely different genesis and another regional-tectonic situation the existence of cryogenic fissures is excluded for the salt dome Gorleben. The salt-geologic and experimental studies on the deformation of anhydrite layers in salt domes are summarized and evaluated with respect to the long-term consequences for a potential final repository for high-level heat-generating radioactive waste in the salt dome Gorleben. The studies confirm the older BGR studies that anhydrite layers do not represent hydraulic potential ling-distance liquid paths.

  12. Partial diel migration: A facultative migration underpinned by long-term inter-individual variation.

    Science.gov (United States)

    Harrison, Philip M; Gutowsky, Lee F G; Martins, Eduardo G; Patterson, David A; Cooke, Steven J; Power, Michael

    2017-09-01

    The variations in migration that comprise partial diel migrations, putatively occur entirely as a consequence of behavioural flexibility. However, seasonal partial migrations are increasingly recognised to be mediated by a combination of reversible plasticity in response to environmental variation and individual variation due to genetic and environmental effects. Here, we test the hypothesis that while partial diel migration heterogeneity occurs primarily due to short-term within-individual flexibility in behaviour, long-term individual differences in migratory behaviour also underpin this migration variation. Specifically, we use a hierarchical behavioural reaction norm approach to partition within- and among-individual variation in depth use and diel plasticity in depth use, across short- and long-term time-scales, in a group of 47 burbot (Lota lota) tagged with depth-sensing acoustic telemetry transmitters. We found that within-individual variation at the among-dates-within-seasons and among-seasons scale, explained the dominant proportion of phenotypic variation. However, individuals also repeatedly differed in their expression of migration behaviour over the 2 year study duration. These results reveal that diel migration variation occurs primarily due to short-term within-individual flexibility in depth use and diel migration behaviour. However, repeatable individual differences also played a key role in mediating partial diel migration. These findings represent a significant advancement of our understanding of the mechanisms generating the important, yet poorly understood phenomena of partial diel migration. Moreover, given the pervasive occurrence of diel migrations across aquatic taxa, these findings indicate that individual differences have an important, yet previously unacknowledged role in structuring the temporal and vertical dynamics of aquatic ecosystems. © 2017 The Authors. Journal of Animal Ecology © 2017 British Ecological Society.

  13. Networks and Selection in International Migration to Spain

    DEFF Research Database (Denmark)

    Neubecker, Nina; Smolka, Marcel; Steinbacher, Anne

    This paper provides new evidence on migrant networks as determinants of the scale and skill structure of migration, using aggregate data from a recent migration boom to Spain. We develop a three-level nested multinomial logit migration model. Our model accommodates varying degrees of similarity...

  14. The influence of raw material, added emulsifying salt and spray drying on cheese powder structure and hydration properties

    DEFF Research Database (Denmark)

    Felix da Silva, Denise; Larsen, Flemming Hofmann; Hougaard, Anni Bygvrå

    2017-01-01

    The present work has evaluated how raw material, addition of emulsifying salts (ES) and drying technology affect particle characteristics, structure, and hydration of cheese powders. In this context the spray drying technology induced the strongest effect on morphology and swelling of cheese powder...

  15. HAW simulation experiments with cobalt-60 radiation sources in the Asse salt mine

    International Nuclear Information System (INIS)

    Rothfuchs, T.; Wieczorek, K.; Feddersen, H.K.

    1986-01-01

    The report describes the experimental work and the measured data of the joint German-American project for the HAW simulation experiment with cobalt-60 radiation sources in the Asse salt mine, covering the period up to the end of the third quarter 1986. The experiment is intended to yield information on the synergistic effects of heat and ionizing radiation on the salt rock under representative waste repository conditions. The investigations aim at the migration, release, and radiolytic decomposition of the water and gas components in the rock salt, and at the thermally induced strain and deformation processes. In addition, corrosion tests are planned to be made on various container test materials, and analyses of salt rock core samples for assessing the effect of heat and radiation on the rock. The report in hand presents all data obtained during the experiment. The results of the subsequent evaluation and verification studies will be presented in another report, the programme being given in an annex to the report in hand. (orig./RB) [de

  16. Mixed sodium nickel-manganese sulfates: Crystal structure relationships between hydrates and anhydrous salts

    Energy Technology Data Exchange (ETDEWEB)

    Marinova, Delyana M.; Zhecheva, Ekaterina N.; Kukeva, Rositsa R.; Markov, Pavel V. [Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Nihtianova, Diana D. [Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Institute of Mineralogy and Crystallography, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Stoyanova, Radostina K., E-mail: radstoy@svr.igic.bas.bg [Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria)

    2017-06-15

    The present contribution provides new structural and spectroscopic data on the formation of solid solutions between hydrated and dehydrated sulfate salts of sodium-nickel and sodium-manganese in a whole concentration range: Na{sub 2}Ni{sub 1−x}Mn{sub x}(SO{sub 4}){sub 2}·yH{sub 2}O, 0≤ x≤1.0. Using powder XRD, electron paramagnetic resonance spectroscopy (EPR), IR and Raman spectroscopy it has been found that double sodium-nickel and sodium-manganese salts form solid solutions Na{sub 2}Ni{sub 1−x}Mn{sub x}(SO{sub 4}){sub 2}·4H{sub 2}O with a blödite-type of structure within a broad concentration range of 0≤x≤0.49, while the manganese rich compositions Na{sub 2}Ni{sub 1−x}Mn{sub x}(SO{sub 4}){sub 2}·2H{sub 2}O (0.97≤x≤1.0) crystallize in the kröhnkite-type of structure. The Ni-based blödites Na{sub 2}Ni{sub 1−x}Mn{sub x}(SO{sub 4}){sub 2}·4H{sub 2}O dehydrate between 140 and 260 °C into anhydrous salts Na{sub 2}Ni{sub 1−x}Mn{sub x}(SO{sub 4}){sub 2}, 0≤ x≤0.44, with a structure where Ni{sub 1−x}Mn{sub x}O{sub 6} octahedra are bridged into pairs by edge- and corner sharing SO{sub 4}{sup 2−} groups. Both TEM and EPR methods show that the Ni{sup 2+} and Mn{sup 2+} ions are homogenously distributed over three crystallographic positions of the large monoclinic cell. The dehydration of the kröhnkite phase Na{sub 2}Ni{sub 1−x}Mn{sub x}(SO{sub 4}){sub 2}·2H{sub 2}O yields the alluaudite phase Na{sub 2+δ}Mn{sub 2-δ/2}(SO{sub 4}){sub 3}, where the Na-to-Mn ratio decreases and all Ni{sup 2+} dopants are released from the structure. The process of the dehydration is discussed in terms of structural aspects taking into account the distortion degree of the Ni,MnO{sub 6} and SO{sub 4} polyhedra. - Graphical abstract: Thermal dehydration of the blödite phase Na{sub 2}Ni{sub 1−x}Mn{sub x}(SO{sub 4}){sub 2}·4H{sub 2}O (0≤ x≤0.49) yields nickel-manganese sulfates Na{sub 2}Ni{sub 1−x}Mn{sub x}(SO{sub 4}){sub 2} (0≤ x≤0.44) with

  17. Strong Migration Limit for Games in Structured Populations: Applications to Dominance Hierarchy and Set Structure

    Directory of Open Access Journals (Sweden)

    Dhaker Kroumi

    2015-09-01

    Full Text Available In this paper, we deduce a condition for a strategy S1 to be more abundant on average at equilibrium under weak selection than another strategy S2 in a population structured into a finite number of colonies of fixed proportions as the population size tends to infinity. It is assumed that one individual reproduces at a time with some probability depending on the payoff received in pairwise interactions within colonies and between colonies and that the offspring replaces one individual chosen at random in the colony into which the offspring migrates. It is shown that an expected weighted average equilibrium frequency of S1 under weak symmetric strategy mutation between S1 and S2 is increased by weak selection if an expected weighted payoff of S1 near neutrality exceeds the corresponding expected weighted payoff of S2. The weights are given in terms of reproductive values of individuals in the different colonies in the neutral model. This condition for S1 to be favoured by weak selection is obtained from a strong migration limit of the genealogical process under neutrality for a sample of individuals, which is proven using a two-time scale argument. The condition is applied to games between individuals in colonies with linear or cyclic dominance and between individuals belonging to groups represented by subsets of a given set.

  18. Control of molten salt corrosion of fusion structural materials by metallic beryllium

    International Nuclear Information System (INIS)

    Calderoni, P.; Sharpe, P.; Nishimura, H.; Terai, T.

    2009-01-01

    A series of tests have been performed between 2001 and 2006 at the Safety and Tritium Applied Research facility of the Idaho National Laboratory to demonstrate chemical compatibility between the molten salt flibe (2LiF + BeF 2 in moles) and fusion structural materials once suitable fluoride potential control methods are established. The tests adopted metallic beryllium contact as main fluoride potential control, and the results have been published in recent years. A further step was to expose two specimens of low activation ferritic/martensitic steel 9Cr-2W to static corrosion tests that include an active corrosion agent (hydrofluoric gas) in controlled conditions at 530 deg. C, and the results of the tests are presented in this paper. The results confirmed the expected correlation of the HF recovery with the concentration of metallic impurities dissolved in the salt because of specimen corrosion. The metals concentration dropped to levels close to the detectable limit when the beryllium rod was inserted and increased once the content of excess beryllium in the system had been consumed by HF reduction and specimen corrosion progressed. Metallographic analysis of the samples after 500 h exposure in reactive conditions showed evidence of the formation of unstable chromium oxide layers on the specimen's surface.

  19. Mechanism of growth, composition and structure of oxide films formed on ferrous alloys in molten salt electrolytes - a review

    International Nuclear Information System (INIS)

    Tzvetkoff, Tz.; Kolchakov, J.

    2004-01-01

    The growth kinetics, chemical composition and structure of scales formed during corrosion of Fe and its alloys in molten salts are reviewed. Special attention is paid to the effect of the composition of the molten salt mixture and the gas atmosphere on the stability and protective ability of corrosion layers. First, the thermodynamical background of the corrosion and oxidation of Fe-base engineering materials in molten salt media is briefly commented. A concise review of the growth kinetics of passivating oxide films is also presented. These two introductory chapters serve as a guide for the extensive survey of the growth mechanism, nature and properties of oxide and related scales on ferrous alloys in a range of molten electrolytes - chlorides, nitrates, sulphates, carbonates, hydroxides and mixtures thereof in gas atmospheres containing O 2 , CO 2 , SO 2 , SO 3 and HCl

  20. Supramolecular Assembly of Complementary Cyanine Salt J-Aggregates

    KAUST Repository

    Li, Zhong’ an; Mukhopadhyay, Sukrit; Jang, Sei-Hum; Bredas, Jean-Luc; Jen, Alex K.-Y.

    2015-01-01

    An understanding of structure–property relationships in cyanine dyes is critical for their design and application. Anionic and cationic cyanines can be organized into complementary cyanine salts, offering potential building blocks to modulate their intra/intermolecular interactions in the solid state. Here, we demonstrate how the structures of these complementary salts can be tuned to achieve highly ordered J-type supramolecular aggregate structures of heptamethine dyes in crystalline solids.

  1. Supramolecular Assembly of Complementary Cyanine Salt J-Aggregates

    KAUST Repository

    Li, Zhong’an

    2015-09-09

    An understanding of structure–property relationships in cyanine dyes is critical for their design and application. Anionic and cationic cyanines can be organized into complementary cyanine salts, offering potential building blocks to modulate their intra/intermolecular interactions in the solid state. Here, we demonstrate how the structures of these complementary salts can be tuned to achieve highly ordered J-type supramolecular aggregate structures of heptamethine dyes in crystalline solids.

  2. A new shape design method of salt cavern used as underground gas storage

    International Nuclear Information System (INIS)

    Wang, Tongtao; Yan, Xiangzhen; Yang, Henglin; Yang, Xiujuan; Jiang, Tingting; Zhao, Shuai

    2013-01-01

    Graphical abstract: Safety factor contours of four salt cavern gas storages after running 10 years. Highlights: ► We propose a new model to design the shape of salt cavern gas storage. ► The concepts of slope instability and pressure arch are introduced into the shape design. ► The max. gas pressure determines the shapes and dimensions of cavern lower structure. ► The min. gas pressure decides the shapes and dimensions of cavern upper structure. - Abstract: A new model used to design the shape and dimension of salt cavern gas storage is proposed in the paper. In the new model, the cavern is divided into two parts, namely the lower and upper structures, to design. The concepts of slope instability and pressure arch are introduced into the shape design of the lower and upper structures respectively. Calculating models are established according to the concepts. Field salt cavern gas storage in China is simulated as examples, and its shape and dimension are proposed. The effects of gas pressure, friction angle and cohesion of rock salt on the cavern stability are discussed. Moreover, the volume convergence, displacement, plastic volume rate, safety factor, and effective strain are compared with that of three other existing shapes salt caverns to validate the performance of newly proposed cavern. The results show that the max. gas pressure determines the shape and dimension of cavern lower structure, while the min. gas pressure decides that of cavern upper structure. With the increase of friction angle and cohesion of rock salt, the stability of salt cavern is increased. The newly proposed salt cavern gas storage has more notable advantages than the existing shapes of salt cavern in volume convergence, displacement, plastic volume rate, safety factor, and effective strain under the same conditions

  3. Population structure, migration, and diversifying selection in the Netherlands

    Science.gov (United States)

    Abdellaoui, Abdel; Hottenga, Jouke-Jan; Knijff, Peter de; Nivard, Michel G; Xiao, Xiangjun; Scheet, Paul; Brooks, Andrew; Ehli, Erik A; Hu, Yueshan; Davies, Gareth E; Hudziak, James J; Sullivan, Patrick F; van Beijsterveldt, Toos; Willemsen, Gonneke; de Geus, Eco J; Penninx, Brenda W J H; Boomsma, Dorret I

    2013-01-01

    Genetic variation in a population can be summarized through principal component analysis (PCA) on genome-wide data. PCs derived from such analyses are valuable for genetic association studies, where they can correct for population stratification. We investigated how to capture the genetic population structure in a well-characterized sample from the Netherlands and in a worldwide data set and examined whether (1) removing long-range linkage disequilibrium (LD) regions and LD-based SNP pruning significantly improves correlations between PCs and geography and (2) whether genetic differentiation may have been influenced by migration and/or selection. In the Netherlands, three PCs showed significant correlations with geography, distinguishing between: (1) North and South; (2) East and West; and (3) the middle-band and the rest of the country. The third PC only emerged with minimized LD, which also significantly increased correlations with geography for the other two PCs. In addition to geography, the Dutch North–South PC showed correlations with genome-wide homozygosity (r=0.245), which may reflect a serial-founder effect due to northwards migration, and also with height (♂: r=0.142, ♀: r=0.153). The divergence between subpopulations identified by PCs is partly driven by selection pressures. The first three PCs showed significant signals for diversifying selection (545 SNPs - the majority within 184 genes). The strongest signal was observed between North and South for the functional SNP in HERC2 that determines human blue/brown eye color. Thus, this study demonstrates how to increase ancestry signals in a relatively homogeneous population and how those signals can reveal evolutionary history. PMID:23531865

  4. Indonesia's migration transition.

    Science.gov (United States)

    Hugo, G

    1995-01-01

    This article describes population movements in Indonesia in the context of rapid and marked social and economic change. Foreign investment in Indonesia is increasing, and global mass media is available to many households. Agriculture is being commercialized, and structural shifts are occurring in the economy. Educational levels are increasing, and women's role and status are shifting. Population migration has increased over the decades, both short and long distance, permanent and temporary, legal and illegal, and migration to and between urban areas. This article focuses specifically on rural-to-urban migration and international migration. Population settlements are dense in the agriculturally rich inner areas of Java, Bali, and Madura. Although the rate of growth of the gross domestic product was 6.8% annually during 1969-94, the World Bank ranked Indonesia as a low-income economy in 1992 because of the large population size. Income per capita is US $670. Indonesia is becoming a large exporter of labor to the Middle East, particularly women. The predominance of women as overseas contract workers is changing women's role and status in the family and is controversial due to the cases of mistreatment. Malaysia's high economic growth rate of over 8% per year means an additional 1.3 million foreign workers and technicians are needed. During the 1980s urban growth increased at a very rapid rate. Urban growth tended to occur along corridors and major transportation routes around urban areas. It is posited that most of the urban growth is due to rural-to-urban migration. Data limitations prevent an exact determination of the extent of rural-to-urban migration. More women are estimated to be involved in movements to cities during the 1980s compared to the 1970s. Recruiters and middlemen have played an important role in rural-to-urban migration and international migration.

  5. Charge ordered insulating phases of DODHT salts with octahedral anions and a new radical salt, β''-(DODHT)2TaF6

    Science.gov (United States)

    Nishikawa, H.; Oshio, H.; Higa, M.; Kondo, R.; Kagoshima, S.; Nakao, A.; Sawa, H.; Yasuzuka, S.; Murata, K.

    2008-10-01

    Physical properties of isostructural β''-(DODHT)2X [DODHT = (l,4-dioxane-2,3-diyldithio)dihydrotetrathiafulvalene; X = PF6, AsF6, and SbF6] at ambient pressure have been compared. The insulating phase of β''-(DODHT)2PF6 salt has already been revealed to be a charge ordering (CO) state by X-ray diffraction study and magnetic behavior. CO in this salt was also confirmed by the observation of satellite reflections in oscillation photograph using synchrotron radiation. Transport property of β''-(DODHT)2SbF6 salt was reinvestigated up to the pressure of 3.7 GPa applied by a cubic anvil apparatus. Although the SbF6 salt turned to be metallic above 2.0 GPa, no superconductivity was observed. In order to examine the anion size dependence of DODHT salts with octahedral anions, we prepared a new DODHT salt, β''-(DODHT)2TaF6, which has the larger counter anion compared with the previous salts. Crystal structure of this salt was isostructural to the other DODHT salts. The electrical and magnetic properties of this salt were similar to those of β''-(DODHT)2SbF6 salt.

  6. Effect of Elevated Salt Concentrations on the Aerobic Granular Sludge Process : Linking Microbial Activity with Microbial Community Structure

    NARCIS (Netherlands)

    Bassin, J.P.; Pronk, M.; Muyzer, G.; Kleerebezem, R.; Dezotti, M.; Van Loosdrecht, M.C.M.

    2011-01-01

    The long- and short-term effects of salt on biological nitrogen and phosphorus removal processes were studied in an aerobic granular sludge reactor. The microbial community structure was investigated by PCR-denaturing gradient gel electrophoresis (DGGE) on 16S rRNA and amoA genes. PCR products

  7. Vitrification in the presence of salts

    International Nuclear Information System (INIS)

    Marra, J.C.; Andrews, M.K.; Schumacher, R.F.

    1994-01-01

    Glass is an advantageous material for the immobilization of nuclear wastes because of the simplicity of processing and its unique ability to accept a wide variety of waste elements into its network structure. Unfortunately, some anionic species which are present in the nuclear waste streams have only limited solubility in oxide glasses. This can result in either vitrification concerns or it can affect the integrity, of the final vitrified waste form. The presence of immiscible salts can also corrode metals and refractories in the vitrification unit as well as degrade components in the off-gas system. The presence of a molten salt layer on the melt may alter the batch melting rate and increase operational safety concerns. These safety concerns relate to the interaction of the molten salt and the melter cooling fluids. Some preliminary data from ongoing experimental efforts examining the solubility of molten salts in glasses and the interaction of salts with melter component materials is included

  8. Migration Rate Of Tidal Meanders: Inferences From The Venice Lagoon

    Science.gov (United States)

    Finotello, A.; D'Alpaos, A.; Ghinassi, M.; Lanzoni, S.; Marani, M.; Rinaldo, A.

    2015-12-01

    Meandering channels are ubiquitous features of tidal landscapes. However, despite their fundamental role on the eco-morphodynamic evolution of these landscapes, tidal meanders have received less attention when compared to their fluvial counterparts. Improving current understanding of tidal meander migration, a largely-examined topic in fluvial landscapes, is a key step to highlight analogies and differences between tidal and fluvial cases. The migration of about 400 meander bends, belonging to 40 salt-marsh channels in the Northern Venice Lagoon (Italy), from 1968 to nowadays, has been investigated by means of both a classical method in fluvial frameworks and new procedure. Similarities with fluvial meanders occur, although important difference also emerge. Meanders cutting through the San Felice marsh follow the relationship between cartesian length and channel width, typical of meanders developed within different settings. However, meander migration rates proved to be smaller than those characterizing fluvial meanders. Indeed, the analysis of meander migration suggests a mean migration rate of about 0.10 m/year, consistent with the few data available in the literature. As for the fluvial case, the maximum-potential migration rate (i.e. the envelope curve of the relationship between migration rate and bend radius, both divided by channel width) reaches a maximum for radius-over-width ratio included between 2 and 3, regardless of the considered method. Nevertheless, the new-proposed method allows us to provide a more objective and continuous characterization. By using this new procedure, the channel curvature has finally been Fourier-analyzed, confirming the importance of even harmonics along the curvature spectrum. A correlation between migration rates and dominant harmonics seems to drive the evolution of tidal meanders and might represent a key-feature to distinguish them from their fluvial counterparts.

  9. Physicians' Migration: Perceptions of Pakistani Medical Students.

    Science.gov (United States)

    Hossain, Nazli; Shah, Nusrat; Shah, Tahira; Lateef, Sidra Binte

    2016-08-01

    To study the perceptions of medical students about factors responsible for physicians'migration. Cross-sectional survey. Dow Medical College and Civil Hospital, Karachi, from April to May 2015. Aself-administered structured questionnaire was used including demographic details, attitudes about push and pull factors of migration, and reasons for migrating or not migrating abroad. Final year students and interns were included. Likert scale from 1 to 4 (1=strongly disagree to 4=strongly agree) was used to assess attitudes. Data was analyzed by SPSS version 16. Atotal of 240 medical students, mostly females (n=181, 75%) (60% final year and 40% interns), participated in the study. Majority wished to go abroad (n=127; 54%) with United States being the favourite destination (n=80; 66.1%) and internal medicine fields being the preferred choice for specialization (n=126; 54%). The major pull factors were better quality of postgraduate education abroad (n=110; 48.2%) and economic prospects (80; 35.2%); while the push factors were a weak healthcare system (n=219; 94.3%), inadequate salary structure (n=205; 88.3%), insecurity (n=219; 93.9%) and increasing religious intolerance in Pakistan (n=183; 78.5%). This survey highlights the continuing trend of physician migration from Pakistan owing to an interplay of various push and pull factors. Majority of our medical students wish to migrate, mainly due to low salaries, poor job structure, and insecurity. Urgent interventions are required to reverse this trend of medical brain-drain.

  10. Liking, salt taste perception and use of table salt when consuming reduced-salt chicken stews in light of South Africa's new salt regulations.

    Science.gov (United States)

    De Kock, H L; Zandstra, E H; Sayed, N; Wentzel-Viljoen, E

    2016-01-01

    This study investigated the impact of salt reduction on liking, salt taste perception, and use of table salt when consuming chicken stew in light of South Africa's new salt recommendations. In total, 432 South-African consumers (aged 35.2 ± 12.3 years) consumed a full portion of a chicken stew meal once at a central location. Four stock cube powders varying in salt content were used to prepare chicken stews: 1) no reduction - 2013 Na level; regular salt level as currently available on the South African market (24473 mg Na/100 g), 2) salt reduction smaller than 2016 level, i.e. 10%-reduced (22025 mg Na/100 g), 3) 2016 salt level, as per regulatory prescriptions (18000 mg Na/100 g), 4) 2019 salt level, as per regulatory prescriptions (13000 mg Na/100 g). Consumers were randomly allocated to consume one of the four meals. Liking, salt taste perception, and use of table salt and pepper were measured. Chicken stews prepared with reduced-salt stock powders were equally well-liked as chicken stews with the current salt level. Moreover, a gradual reduction of the salt in the chicken stews resulted in a reduced salt intake, up to an average of 19% for the total group compared to the benchmark 2013 Na level stew. However, 19% of consumers compensated by adding salt back to full compensation in some cases. More salt was added with increased reductions of salt in the meals, even to the point of full compensation. Further investigation into the impacts of nutrition communication and education about salt reduction on salt taste perception and use is needed. This research provides new consumer insights on salt use and emphasises the need for consumer-focused behaviour change approaches, in addition to reformulation of products. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Development of High Throughput Salt Separation System with Integrated Liquid Salt Separation - Salt Distillation Assembly

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Sangwoon; Park, K. M.; Kim, J. G.; Jeong, J. H.; Lee, S. J.; Park, S. B.; Kim, S. S.

    2013-01-15

    The capacity of a salt distiller should be sufficiently large to reach the throughput of uranium electro-refining process. In this study, an assembly composing a liquid separation sieve and a distillation crucible was developed for the sequential operation of a liquid salt separation and a vacuum distillation in the same tower. The feasibility of the sequential salt separation was examined by the rotation test of the sieve-crucible assembly and sequential operation of a liquid salt separation and a vacuum distillation. The adhered salt in the uranium deposits was removed successfully. The salt content in the deposits was below 0.1 wt% after the sequential operation of the liquid salt separation - salt distillation. From the results of this study, it could be concluded that efficient salt separation can be realized by the sequential operation of liquid salt separation and vacuum distillation in one distillation tower since the operation procedures are simplified and no extra operation of cooling and reheating is necessary.

  12. Measurement of europium (III)/europium (II) couple in fluoride molten salt for redox control in a molten salt reactor concept

    Science.gov (United States)

    Guo, Shaoqiang; Shay, Nikolas; Wang, Yafei; Zhou, Wentao; Zhang, Jinsuo

    2017-12-01

    The fluoride molten salt such as FLiNaK and FLiBe is one of the coolant candidates for the next generation nuclear reactor concepts, for example, the fluoride salt cooled high temperature reactor (FHR). For mitigating corrosion of structural materials in molten fluoride salt, the redox condition of the salts needs to be monitored and controlled. This study investigates the feasibility of applying the Eu3+/Eu2+ couple for redox control. Cyclic voltammetry measurements of the Eu3+/Eu2+ couple were able to obtain the concentrations ratio of Eu3+/Eu2+ in the melt. Additionally, the formal standard potential of Eu3+/Eu2+ was characterized over the FHR's operating temperatures allowing for the application of the Nernst equation to establish a Eu3+/Eu2+ concentration ratio below 0.05 to prevent corrosion of candidate structural materials. A platinum quasi-reference electrode with potential calibrated by potassium reduction potential is shown as reliable for the redox potential measurement. These results show that the Eu3+/Eu2+ couple is a feasible redox buffering agent to control the redox condition in molten fluoride salts.

  13. Least-squares reverse time migration of multiples

    KAUST Repository

    Zhang, Dongliang

    2013-12-06

    The theory of least-squares reverse time migration of multiples (RTMM) is presented. In this method, least squares migration (LSM) is used to image free-surface multiples where the recorded traces are used as the time histories of the virtual sources at the hydrophones and the surface-related multiples are the observed data. For a single source, the entire free-surface becomes an extended virtual source where the downgoing free-surface multiples more fully illuminate the subsurface compared to the primaries. Since each recorded trace is treated as the time history of a virtual source, knowledge of the source wavelet is not required and the ringy time series for each source is automatically deconvolved. If the multiples can be perfectly separated from the primaries, numerical tests on synthetic data for the Sigsbee2B and Marmousi2 models show that least-squares reverse time migration of multiples (LSRTMM) can significantly improve the image quality compared to RTMM or standard reverse time migration (RTM) of primaries. However, if there is imperfect separation and the multiples are strongly interfering with the primaries then LSRTMM images show no significant advantage over the primary migration images. In some cases, they can be of worse quality. Applying LSRTMM to Gulf of Mexico data shows higher signal-to-noise imaging of the salt bottom and top compared to standard RTM images. This is likely attributed to the fact that the target body is just below the sea bed so that the deep water multiples do not have strong interference with the primaries. Migrating a sparsely sampled version of the Marmousi2 ocean bottom seismic data shows that LSM of primaries and LSRTMM provides significantly better imaging than standard RTM. A potential liability of LSRTMM is that multiples require several round trips between the reflector and the free surface, so that high frequencies in the multiples suffer greater attenuation compared to the primary reflections. This can lead to lower

  14. Sea Salt vs. Table Salt: What's the Difference?

    Science.gov (United States)

    ... and healthy eating What's the difference between sea salt and table salt? Answers from Katherine Zeratsky, R.D., L.D. The main differences between sea salt and table salt are in their taste, texture ...

  15. Electronic structure and O vacancy formation/migration in La0.825(Mg/Ca/Ba)0.125CoO3

    KAUST Repository

    Omotayo Akande, Salawu

    2016-05-05

    The effect of A-site hole doping (Mg2+, Ca2+ or Ba2+) on the electronic and magnetic properties as well as the O vacancy formation and migration in perovskite LaCoO3 is studied using first-principles calculations. All three dopants are found to facilitate O vacancy formation. Substitution of La3+ with Ba2+/Mg2+ yields the lowest O vacancy formation energy for low/intermediate spin Co, implying that not only the structure but also the spin state of Co is a key parameter. Only for low spin Co the ionic radius is correlated with the O migration barrier. Enhanced migration for intermediate spin Co is ascribed to the availability of additional space at the transition state. © CopyrightEPLA, 2016.

  16. Migration of Water Pulse Through Fractured Porous Media

    International Nuclear Information System (INIS)

    Finsterle, S.; Fabryka-Martin, J. T.; Wang, J. S. Y.

    2001-01-01

    Contaminant transport from waste-disposal sites is strongly affected by the presence of fractures and the degree of fracture-matrix interaction. Characterization of potential contaminant plumes at such sites is difficult, both experimentally and numerically. Simulations of water flow through fractured rock were performed to examine the penetration depth of a large pulse of water entering such a system. Construction water traced with lithium bromide was released during the excavation of a tunnel at Yucca Mountain, Nevada, which is located in an unsaturated fractured tuff formation. Modeling of construction-water migration is qualitatively compared with bromide-to-chloride (Br/CI) ratio data for pore-water salts extracted from drillcores. The influences of local heterogeneities in the fracture network and variations in hydrogeologic parameters were examined by sensitivity analyses and Monte Carlo simulations. The simulation results are qualitatively consistent with the observed Br/CI signals, although these data may only indicate a minimum penetration depth, and water may have migrated further through the fracture network

  17. Women Moving Within Borders: Gender and Internal Migration ...

    African Journals Online (AJOL)

    Internal migration is an inherent part of the processes of development and structural transformation in any region. In Africa, while the focus is often on international migration, internal migration is far more significant for development in terms of the numbers of people moving and their poverty reduction potential and well-being ...

  18. Migration of accreting giant planets

    Science.gov (United States)

    Robert, C.; Crida, A.; Lega, E.; Méheut, H.

    2017-09-01

    Giant planets forming in protoplanetary disks migrate relative to their host star. By repelling the gas in their vicinity, they form gaps in the disk's structure. If they are effectively locked in their gap, it follows that their migration rate is governed by the accretion of the disk itself onto the star, in a so-called type II fashion. Recent results showed however that a locking mechanism was still lacking, and was required to understand how giant planets may survive their disk. We propose that planetary accretion may play this part, and help reach this slow migration regime.

  19. Migration signatures across the decades: Net migration by age in U.S. counties, 1950-2010

    Directory of Open Access Journals (Sweden)

    Richelle L. Winkler

    2015-05-01

    Full Text Available Background: Migration is the primary population redistribution process in the United States. Selective migration by age, race/ethnic group, and spatial location governs population integration, affects community and economic development, contributes to land use change, and structures service needs. Objective: Delineate historical net migration patterns by age, race/ethnic, and rural-urban dimensions for United States counties. Methods: Net migration rates by age for all US counties are aggregated from 1950−2010, summarized by rural-urban location and compared to explore differential race/ethnic patterns of age-specific net migration over time. Results: We identify distinct age-specific net migration 'signatures' that are consistent over time within county types, but different by rural-urban location and race/ethnic group. There is evidence of moderate population deconcentration and diminished racial segregation between 1990 and 2010. This includes a net outflow of Blacks from large urban core counties to suburban and smaller metropolitan counties, continued Hispanic deconcentration, and a slowdown in White counterurbanization. Conclusions: This paper contributes to a fuller understanding of the complex patterns of migration that have redistributed the U.S. population over the past six decades. It documents the variability in county age-specific net migration patterns both temporally and spatially, as well as the longitudinal consistency in migration signatures among county types and race/ethnic groups.

  20. Raman mapping in the elucidation of solid salt eutectic and near eutectic structures

    DEFF Research Database (Denmark)

    Berg, Rolf W.; Kerridge, D. H.

    2002-01-01

    The distribution of the different components of solidified eutectic or near-eutectic salt mixtures (eutectics) was examined by use of Raman microscope mapping of the structures formed when these melts were slowly cooled. Seven binary and one ternary system were investigated. In most cases...... and the composition. When unidirectional cooling was applied it was possible for the system (KCl-Na2SO4, 60:40 mol/mol) to observe lamellar arrangements of the component phases, in an arrangement closely similar to what is frequently found among metallic or ceramic eutectics. Each area, conglomerate or lamellar, did...

  1. A neutron diffraction study on deuterated Rochelle salt structure at - 195degC paraelectric phase

    International Nuclear Information System (INIS)

    Iwata, Yutaka; Mitani, Shigeshi; Fukui, Susumu; Shibuya, Iwao

    1989-01-01

    Neutron diffraction study on the low temperature paraelectric phase of Rochelle salt was performed using deuterated single crystal specimen. Large anisotropic thermal motions of atoms are found to be prevailing in the lower paraelectric phase. This indicates the disordering of atoms and the analysis by two-site split-atom method showed that a split atom model holds equally well with an ordinary non-split model. By connecting split positions selectively, a disordered paraelectric structure, which is composed of half-occupied units, was obtained. These units can be regarded as ones in the ferroelectric phase according to a deduction from an order-disorder phase transition scheme. A possibility of existence of the 'local disorder' of O(5)-H group in the tartrate molecule was examined by Fourier method and a result proved to be negative. Present disordered model gives better understanding to the phase transition scheme of Rochelle salt than the local disorder model case. (author)

  2. Salt-bridging effects on short amphiphilic helical structure and introducing sequence-based short beta-turn motifs.

    Science.gov (United States)

    Guarracino, Danielle A; Gentile, Kayla; Grossman, Alec; Li, Evan; Refai, Nader; Mohnot, Joy; King, Daniel

    2018-02-01

    Determining the minimal sequence necessary to induce protein folding is beneficial in understanding the role of protein-protein interactions in biological systems, as their three-dimensional structures often dictate their activity. Proteins are generally comprised of discrete secondary structures, from α-helices to β-turns and larger β-sheets, each of which is influenced by its primary structure. Manipulating the sequence of short, moderately helical peptides can help elucidate the influences on folding. We created two new scaffolds based on a modestly helical eight-residue peptide, PT3, we previously published. Using circular dichroism (CD) spectroscopy and changing the possible salt-bridging residues to new combinations of Lys, Arg, Glu, and Asp, we found that our most helical improvements came from the Arg-Glu combination, whereas the Lys-Asp was not significantly different from the Lys-Glu of the parent scaffold, PT3. The marked 3 10 -helical contributions in PT3 were lessened in the Arg-Glu-containing peptide with the beginning of cooperative unfolding seen through a thermal denaturation. However, a unique and unexpected signature was seen for the denaturation of the Lys-Asp peptide which could help elucidate the stages of folding between the 3 10 and α-helix. In addition, we developed a short six-residue peptide with β-turn/sheet CD signature, again to help study minimal sequences needed for folding. Overall, the results indicate that improvements made to short peptide scaffolds by fine-tuning the salt-bridging residues can enhance scaffold structure. Likewise, with the results from the new, short β-turn motif, these can help impact future peptidomimetic designs in creating biologically useful, short, structured β-sheet-forming peptides.

  3. Self-selection and intermunicipal migration in Canada.

    Science.gov (United States)

    Islam, M N; Choudhury, S A

    1991-02-01

    "This paper investigates individual intermunicipal migration behaviour in Canada within the context of a human capital model that adjusts for the migrant's selectivity in computing expected income gains. In addition to the typical regional determinants of migration, housing and labour market characteristics are found to influence intermunicipal migration significantly, the effects differing with age. Structural coefficients remained more or less stable during the decade 1971-1981. It is shown that the failure to adjust income gains for selectivity bias results in an underestimation of the migration-impacts of income gains and municipal-specific factors." excerpt

  4. Molten salt reactors. Synthesis of studies realized between 1973 and 1983. Carbon-materials file

    International Nuclear Information System (INIS)

    1983-03-01

    The study of a molten salt fueled reactor requires a thorough examination of carbon containing materials for moderator, reflectors and structural materials. Are examined: texture, structure, physical and mechanical properties, chemical purity, neutron irradiation, salt-graphite and salt-lead interactions for different types of graphite. [fr

  5. U.S. Department of Energy approaches to the assessment of radionuclide migration for the geologic repository program

    International Nuclear Information System (INIS)

    Luik, A.E. van; Apted, M.J.

    1988-01-01

    Potential radionuclide migration in geologic repositories is being addressed by the U.S. Department of Energy's Office of Civilian Radioactive Waste Management through its Office of Geologic Repositories (OGR). A diversity of geohydrologic settings is being investigated: unsaturated tuff, saturated basalt, and bedded salt. A number of approaches to assessing potential migration are being considered. Mass transfer is prominent among near-field approaches. For far-field analysis of migration in the geosphere, detailed characterizations of potential repository sites will lead to site-specific models describing radionuclide migration for a variety of postulated release scenarios. Finite-element and finite-difference codes are being used and developed to solve the mathematical equations pertinent to far-field assessments. Computational approaches presently in use generally require distribution coefficients to estimate the retardation of specific radionuclides with respect to the transport rate of water. 26 refs

  6. Dynamics of prolonged salt movement in the Glückstadt Graben (NW Germany) driven by tectonic and sedimentary processes

    Science.gov (United States)

    Warsitzka, Michael; Kley, Jonas; Jähne-Klingberg, Fabian; Kukowski, Nina

    2017-01-01

    The formation of salt structures exerted a major influence on the evolution of subsidence and sedimentation patterns in the Glückstadt Graben, which is part of the Central European Basin System and comprises a post-Permian sediment thickness of up to 11 km. Driven by regional tectonics and differential loading, large salt diapirs, salt walls and salt pillows developed. The resulting salt flow significantly influenced sediment distribution in the peripheral sinks adjacent to the salt structures and overprinted the regional subsidence patterns. In this study, we investigate the geometric and temporal evolution of salt structures and subsidence patterns in the central Glückstadt Graben. Along a key geological cross section, the post-Permian strata were sequentially decompacted and restored in order to reconstruct the subsidence history of minibasins between the salt structures. The structural restoration reveals that subsidence of peripheral sinks and salt structure growth were initiated in Early to Middle Triassic time. From the Late Triassic to the Middle Jurassic, salt movement and salt structure growth never ceased, but were faster during periods of crustal extension. Following a phase from Late Jurassic to the end of the early Late Cretaceous, in which minor salt flow occurred, salt movement was renewed, particularly in the marginal parts of the Glückstadt Graben. Subsidence rates and tectonic subsidence derived from backstripping of 1D profiles reveal that especially the Early Triassic and Middle Keuper times were periods of regional extension. Three specific types of salt structures and adjacent peripheral sinks could be identified: (1) Graben centre salt walls possessing deep secondary peripheral sinks on the sides facing away from the basin centre, (2) platform salt walls, whose main peripheral sinks switched multiple times from one side of the salt wall to the other, and (3) Graben edge pillows, which show only one peripheral sink facing the basin centre.

  7. Molten salt breeder reactor

    International Nuclear Information System (INIS)

    Furukawa, Kazuo; Tsukada, Kineo; Nakahara, Yasuaki; Oomichi, Toshihiko; Oono, Hideo.

    1982-01-01

    Purpose: To simplify the structure, as well as improve the technical reliability and safety by the elimination of a proton beam entering window. Constitution: The nuclear reactor container main body is made of Hastelloy N and provided at the inner surface with two layers of graphite shields except for openings. An aperture was formed in the upper surface of the container, through which protons accelerated by a linear accelerator are directly entered to the liquid surface of molten salts such as 7LiF-BeF 2 -ThF 4 , 7LiF-NaF-ThF 4 , 7LiF-Rb-UF 4 , NaF-KF-UF 4 and the like. The heated molten salts are introduced by way of a pipeway into a heat exchanger where the heat is transferred to coolant salts and electric generation is conducted by way of heated steams. (Furukawa, Y.)

  8. Structural analysis of salt cavities formed by solution mining: I. Method of analysis and preliminary results for spherical cavities

    International Nuclear Information System (INIS)

    Fossum, A.F.

    1976-01-01

    The primary objective of this effort is an analysis of the structural stability of cavities formed by solution mining in salt domes. In particular, the effects of depth (i.e. initial state of in situ stress), shape, volume (i.e. physical dimensions of the cavity), and sequence of salt excavation/fluid evacuation on the timewise structural stability of a cavity are of interest. It is anticipated that an assessment can be made of the interrelation between depth, cavern size, and cavern shape or of the practical limits therewith. In general, the cavity shape is assumed to be axisymmetric and the salt is assumed to exhibit nonlinear creep behavior. The primary emphasis is placed on the methodology of the finite element analysis, and the results of preliminary calculations for a spherically shaped cavity. It is common practice for engineers to apply elasticity theory to the behavior of rock in order to obtain near field stresses and displacements around an underground excavation in an effort to assess structural stability. Rock masses, particularly at depth, may be subjected to a rather complex state of initial stress, and may be nonhomogeneous and anisotropic. If one also includes complex geometrical excavation shape, the use of analytical techniques as an analysis tool is practically impossible. Thus, it is almost a necessity that approximate solution techniques be employed. In this regard, the finite element method is ideal as it can handle complex geometries and nonlinear material behavior with relative ease. An unusual feature of the present study is the incorporation into the finite element code of a procedure for handling the gradual creation or excavation of an underground cavity. During the excavation sequence, the salt is permitted to exhibit nonlinear stress-strain-time dependence. The bulk of this report will be devoted to a description of the analysis procedures, together with a preliminary calculation for a spherically shaped cavity

  9. On the isomers of pyridine-4-carboxaldoxime and its nitrate salt, X-ray crystal structure and quantum chemical calculations

    Science.gov (United States)

    Soliman, Saied M.; Albering, Jörg; Abu-Youssef, Morsy A. M.

    2017-07-01

    The reaction between nitric acid and pyridine-4-carboxaldoxime (P4A) afford the corresponding pyridinum nitrate salt (P4AN). Its X-ray structure is measured and compared with the related P4A salts. The DFT/B3LYP results showed that both the P4A and P4AN favored the Syn-I form which has the lowest energy among the other possible isomers. Transition state calculations predicted that the Syn-I form is the thermodynamically and kinetically most stable form. The X-ray solid state structure of the new nitrate salt (P4AN) indicated that the labile proton favored the N-atom of the pyridine ring. DFT studies showed that the same is true for its solution in polar solvents. In contrast, the pyridinium cation is not favored either in the gas phase or solution of P4AN in nonpolar solvent. In these cases, the proton favored to bond with one O-atom from the nitrate group. Second order interaction energies and Mayer bond order values revealed these results. The bond order of the Nsbnd H bond is higher in polar solvents as well as at the experimental structure than either in the gas phase or non polar solvents. The topology parameters obtained from the atoms in molecules (AIM) analysis were used to describe the nature of the Nsbnd H and Osbnd H bonds. The bond critical points (BCP) were found to be close to the H-atoms in case of stronger interaction.

  10. Least-squares Migration and Full Waveform Inversion with Multisource Frequency Selection

    KAUST Repository

    Huang, Yunsong

    2013-09-01

    Multisource Least-Squares Migration (LSM) of phase-encoded supergathers has shown great promise in reducing the computational cost of conventional migration. But for the marine acquisition geometry this approach faces the challenge of erroneous misfit due to the mismatch between the limited number of live traces/shot recorded in the field and the pervasive number of traces generated by the finite-difference modeling method. To tackle this mismatch problem, I present a frequency selection strategy with LSM of supergathers. The key idea is, at each LSM iteration, to assign a unique frequency band to each shot gather, so that the spectral overlap among those shots—and therefore their crosstallk—is zero. Consequently, each receiver can unambiguously identify and then discount the superfluous sources—those that are not associated with the receiver in marine acquisition. To compare with standard migration, I apply the proposed method to 2D SEG/EAGE salt model and obtain better resolved images computed at about 1/8 the cost; results for 3D SEG/EAGE salt model, with Ocean Bottom Seismometer (OBS) survey, show a speedup of 40×. This strategy is next extended to multisource Full Waveform Inversion (FWI) of supergathers for marine streamer data, with the same advantages of computational efficiency and storage savings. In the Finite-Difference Time-Domain (FDTD) method, to mitigate spectral leakage due to delayed onsets of sine waves detected at receivers, I double the simulation time and retain only the second half of the simulated records. To compare with standard FWI, I apply the proposed method to 2D velocity model of SEG/EAGE salt and to Gulf Of Mexico (GOM) field data, and obtain a speedup of about 4× and 8×. Formulas are then derived for the resolution limits of various constituent wavepaths pertaining to FWI: diving waves, primary reflections, diffractions, and multiple reflections. They suggest that inverting multiples can provide some low and intermediate

  11. Crystal and molecular structures of sixteen charge-assisted hydrogen bond-mediated diisopropylammonium salts from different carboxylic acids

    Science.gov (United States)

    Lin, Zhihao; Hu, Kaikai; Jin, Shouwen; Ding, Aihua; Wang, Yining; Dong, Lingfeng; Gao, Xingjun; Wang, Daqi

    2017-10-01

    salts were also reported. And their structural and supramolecular aspects are fully analyzed. The result reveals that among the sixteen investigated crystals the NH groups in the diisopropylamine are protonated when the carboxylic acids are deprotonated, and the crystal packing is interpreted in terms of the strong charge-assisted Nsbnd H⋯O hydrogen bond formation between the ammonium and the deprotonated COOH groups. Except the Nsbnd H⋯O hydrogen bond, the Osbnd H⋯O hydrogen bonds (charge assisted or neutral) were also found at the salts 6, 8, 9, 10, 12, 13, 14, 15, and 16. Further analysis of the crystal packing of the salts indicated that a different family of additional CHsbnd O/CH2sbnd O/CH3sbnd O, CH-π/CH3-π, CH3-Cπ, N-π, and π-π associations contribute to the stabilization and expansion of the total structures. For the coexistence of the various weak interactions these structures adopted homo or hetero supramolecular synthons or both.

  12. Theories of international labor migration: an overview.

    Science.gov (United States)

    Stahl, C W

    1995-01-01

    "Emigration pressures are primarily the result of increasing inequalities between countries which, in turn, are the result of factors internal to less developed countries and their relations with developed countries. Both micro (neoclassical) and macrostructural theories of migration are reviewed. It is argued that the neoclassical theory of migration is often unjustly criticized and is sufficiently robust to incorporate those structural considerations which are at the core of macrostructural theories. Moreover, the neoclassical theory, with slight modification, can incorporate the ¿new economics of migration.' The major empirical problem confronting models of international labor migration is that migration flows are constrained by immigration policy. This policy, in turn, is influenced by various special interest groups. The direction and form of migration flows is conditioned by contemporary and historical relationships between source and destination countries." excerpt

  13. Anisotropic depth migration: reducing lateral-position uncertainty of subsurface structures in the Alberta foothills

    Energy Technology Data Exchange (ETDEWEB)

    Vestrum, R.W.; Lawton, D.C.

    1999-01-01

    Seismic velocity anisotropy causes lateral-positioning errors on seismic images, and the use of anisotropic depth migration corrects this lateral mispositioning of subsurface targets. The assumption of isotropic seismic velocities implies that traditional depth migration corrects only for positioning errors caused by lateral velocity heterogeneity, and mispositioning due to seismic anisotropy remained uncorrected on depth-migrated sections. Also, isotropic depth migration was only applied in cases in which significant lateral velocity changes occurred, and lateral mispositioning due to seismic anisotropy remained uncorrected on time-migrated sections. If seismic is to accurately image the subsurface, then there is a need for reconsidering the assumptions made in depth imaging as well as a need to reconsider at what point depth migration applies to seismic data. Now that it is possible to correct for seismic anisotropy as well as lateral velocity heterogeneity, anisotropic depth migration potentially can be used to improve seismic imaging and positioning in areas in which traditional depth migration did not apply. 5 refs.

  14. Anisotropic depth migration: reducing lateral-position uncertainty of subsurface structures in the Alberta foothills

    Energy Technology Data Exchange (ETDEWEB)

    Vestrum, R.W.; Lawton, D.C.

    1999-11-01

    Seismic velocity anisotropy causes lateral-positioning errors on seismic images, and the use of anisotropic depth migration corrects this lateral mispositioning of subsurface targets. The assumption of isotropic seismic velocities implies that traditional depth migration corrects only for positioning errors caused by lateral velocity heterogeneity, and mispositioning due to seismic anisotropy remained uncorrected on depth-migrated sections. Also, isotropic depth migration was only applied in cases in which significant lateral velocity changes occurred, and lateral mispositioning due to seismic anisotropy remained uncorrected on time-migrated sections. If seismic is to accurately image the subsurface, then there is a need for reconsidering the assumptions made in depth imaging as well as a need to reconsider at what point depth migration applies to seismic data. Now that it is possible to correct for seismic anisotropy as well as lateral velocity heterogeneity, anisotropic depth migration potentially can be used to improve seismic imaging and positioning in areas in which traditional depth migration did not apply. 5 refs.

  15. Migration in a segmented labour market.

    Science.gov (United States)

    Gordon, I

    1995-01-01

    "Current research in migration is moving on from neo-classical and behavioural perspectives to a more structural approach relating to wider processes, issues of power and the particular role of employers. Within this programme a key issue for investigation is the interaction between spatial mobility and the structuring of labour markets. This paper focuses on the significance of labour market segmentation--in terms both of job stability and gender--for migration, both theoretically and through an empirical analysis of data from the UK Labour Force Survey on sponsored and unsponsored moves." excerpt

  16. Mass transport in bedded salt and salt interbeds

    International Nuclear Information System (INIS)

    Hwang, Y.; Pigford, T.H.; Chambre, P.L.; Lee, W.W.L.

    1989-08-01

    Salt is the proposed host rock for geologic repositories of nuclear waste in several nations because it is nearly dry and probably impermeable. Although experiments and experience at potential salt sites indicate that salt may contain brine, the low porosity, creep, and permeability of salt make it still a good choice for geologic isolation. In this paper we summarize several mass-transfer and transport analyses of salt repositories. The mathematical details are given in our technical reports

  17. Return Migration as Failure or Success?: The Determinants of Return Migration Intentions Among Moroccan Migrants in Europe.

    Science.gov (United States)

    de Haas, Hein; Fokkema, Tineke; Fihri, Mohamed Fassi

    Different migration theories generate competing hypotheses with regard to determinants of return migration. While neoclassical migration theory associates migration to the failure to integrate at the destination, the new economics of labour migration sees return migration as the logical stage after migrants have earned sufficient assets and knowledge and to invest in their origin countries. The projected return is then likely to be postponed for sustained or indefinite periods if integration is unsuccessful. So, from an indication or result of integration failure return is rather seen as a measure of success. Drawing on recent survey data ( N  = 2,832), this article tests these hypotheses by examining the main determinants of return intention among Moroccan migrants across Europe. The results indicate that structural integration through labour market participation, education and the maintenance of economic and social ties with receiving countries do not significantly affect return intentions. At the same time, investments and social ties to Morocco are positively related, and socio-cultural integration in receiving countries is negatively related to return migration intentions. The mixed results corroborate the idea that there is no uniform process of (return) migration and that competing theories might therefore be partly complementary.

  18. Role of Silver Salts Lattice Energy on Conductivity Drops in Chitosan Based Solid Electrolyte: Structural, Morphological and Electrical Characteristics

    Science.gov (United States)

    Aziz, Shujahadeen B.; Abdullah, Omed Gh.; Hussein, Sarkawt A.

    2018-03-01

    The influence of anion type on silver ion reduction and drop in direct current (DC) conductivity was investigated experimentally. The structural, optical, morphological and electrical properties of the samples were investigated using x-ray diffraction (XRD), ultraviolet-visible (UV-Vis), optical micrographs (OM) and impedance spectroscopy. The XRD results reveal significant disruption in the crystalline structure of chitosan (CS) for different concentrations of silver nitrate (AgNt) salt. The localized surface resonance plasmonic (LSRP) peaks that were observed for CS:AgNt samples, along with the white silver specs detected by OM technique confirm the formation of Ag nanoparticles. The appearance of obvious dark regions in the CS:AgNt system reveals the existence of a large percentage of amorphous domains. The nonexistence of spherulitic texture confirms the amorphous nature of the samples. The second semicircle in an impedance plot can be attributed to an Ag nanoparticle grain boundary. The established relationships between dielectric constant and carrier concentration and the behavior of dielectric constant versus salt concentration were used to explain the phenomenon of ion-ion association. The continuous increase of DC conductivity was noticed at high temperatures, which was then explained on the basis of lattice energy of silver salts. The influences of anion size on the rate of silver ion reductions are also interpreted.

  19. Ionic structure of solutions of alkali metals and molten salts

    International Nuclear Information System (INIS)

    Chabrier, G.; Senatore, G.; Tosi, M.P.

    1982-02-01

    Neutron diffraction patterns from K-KCl and Rb-RbBr liquid solutions at various compositions are examined in an ionic-mixture model which neglects screening and aggregation due to the metallic electrons. The main feature of the observed diffraction patterns for wave number k above roughly 1A -1 are accounted for by the model. The approach to the metal-rich end of the phase diagram is analyzed in detail from different viewpoints in the K-KCl system. Short-range correlations of the potassium ions are described in this region by a metallic radius deduced from properties of the pure liquid metal, but a simple expanded-metal model must be supplemented by the assumption that considerable disorder is introduced in its structure by the halogen ions. Features of short-range ordering in the salt-rich region that are implied by a shoulder on the high-k side of the main peak in the diffraction pattern are also commented upon. (author)

  20. Geochemical investigation of UMTRAP designated site at Salt Lake City, Utah

    International Nuclear Information System (INIS)

    Markos, G.; Bush, K.J.

    1983-09-01

    This report is the result of a geochemical investigation of the former uranium mill and tailings site at Salt Lake City, Utah. This is one in a series of site specific geochemical investigations performed on the inactive uranium mill tailings included in the Uranium Mill Tailings Remedial Action Project. The objectives of the investigation are to characterize the geochemistry, to determine the contaminant distribution resulting from the former milling activities and tailings, and to infer chemical pathways and transport mechanisms from the contaminant distribution. The results will be used to model contaminant migration and to develop criteria for long-term containment media such as a cover system which is impermeable to contaminant migration. This report assumes a familiarity with the hydrologic conditions of the site and the geochemical concepts underlying the investigation. The results reported are based on a one-time sampling of waters and solid material from the background, the area adjacent to the site, and the site. The solid samples were water extracted to remove easily soluble salts and acid extracted to remove carbonates and hydroxides. The water extracts and solid samples were anlyzed for the major and trace elements. The report includes the methods of sampling, sample processing, analysis, and data interpretation. Four major conclusions are: (1) sediments in the ditches and creeks adjacent to the site contain tailings, however, the waters were generally not contaminated; (2) tailings are mixed with the soils within a meter below the tailings in some locations, however, water-soluble contaminants decrease to below background levels within 30 cm below the tailings; (3) there has not been significant acid seepage into the soils below the tailings; and (4) salt crusts on the tailings contain trace elements, with the elements that form chloride complexes having the greatest accumulation

  1. Examination of Below-Ground Structure and Soil Respiration Rates of Stable and Deteriorating Salt Marshes in Jamaica Bay (NY)

    Science.gov (United States)

    CAT scan imaging is currently being used to examine below-ground peat and root structure in cores collected from salt marshes of Jamaica Bay, part of the Gateway National Recreation Area (NY). CAT scans or Computer-Aided Tomography scans use X-ray equipment to produce multiple i...

  2. Artificial coastal lagoons at solar salt-working sites: A network of habitats for specialised, protected and alien biodiversity

    Science.gov (United States)

    Herbert, Roger J. H.; Broderick, Lee G.; Ross, Kathryn; Moody, Chris; Cruz, Tamira; Clarke, Leo; Stillman, Richard A.

    2018-04-01

    There are concerns that novel structures might displace protected species, facilitate the spread of non-indigenous species, or modify native habitats. It is also predicted that ocean warming and the associated effects of climate change will significantly increase biodiversity loss within coastal regions. Resilience is to a large extent influenced by the magnitude of dispersal and level of connectivity within and between populations. Therefore it is important to investigate the distribution and ecological significance of novel and artificial habitats, the presence of protected and alien species and potential vectors of propagule dispersal. The legacy of solar salt-making in tropical and warm temperate regions is regionally extensive areas of artificial hypersaline ponds, canals and ditches. Yet the broad-scale contribution of salt-working to a network of benthic biodiversity has not been fully established. Artisanal, abandoned and historic salt-working sites were investigated along the Atlantic coast of Europe between southern England (50°N) and Andalucía, Spain (36°N). Natural lagoons are scarce along this macrotidal coast and are vulnerable to environmental change; however it is suspected that avian propagule dispersal is important in maintaining population connectivity. During bird migration periods, benthic cores were collected for infauna from 70 waterbodies across 21 salt-working sites in 5 coastal regions. Bird ringing data were used to investigate potential avian connectivity between locations. Lagoonal specialist species, some of international conservation importance, were recorded across all regions in the storage reservoirs and evaporation ponds of continental salinas, yet few non-indigenous species were observed. Potential avian propagule transport and connectivity within and between extant salt-working sites is high and these artificial habitats are likely to contribute significantly to a network of coastal lagoon biodiversity in Europe.

  3. A way to limit the corrosion in the Molten Salt Reactor concept: the salt redox potential control

    International Nuclear Information System (INIS)

    Gibilaro, M.; Massot, L.; Chamelot, P.

    2015-01-01

    The possibility of controlling the salt redox potential thanks to a redox buffer in the Molten Salt Fast Reactor was investigated, the goal was to limit the oxidation of the reactor structural material. Tests were performed in LiF-CaF 2 at 850 °C on two different redox couples to fix the salt potential, Eu(III)/Eu(II) and U(IV)/U(III), where the first one was used as inactive system to validate the methodology to be applied on the uranium system. A metallic reducing agent (Gd plate for Eu, and U plate for U system) was inserted in the salt, leading to a spontaneous reaction: Eu(III) and U(IV) were then reduced. Eu(III) was fully converted into Eu(II) with metallic Gd, validating the approach. On the U system, the U(IV)/U(III) ratio has to be set between 10 and 100 to limit the core material oxidation: addition of metallic U decreased the concentration ratio from the infinite to 1, showing the feasibility of the salt redox potential control with the U system

  4. Deracemization of Axially Chiral Nicotinamides by Dynamic Salt Formation with Enantiopure Dibenzoyltartaric Acid (DBTA

    Directory of Open Access Journals (Sweden)

    Fumitoshi Yagishita

    2013-11-01

    Full Text Available Dynamic atroposelective resolution of chiral salts derived from oily racemic nicotinamides and enantiopure dibenzoyltartaric acid (DBTA was achieved by crystallization. The absolute structures of the axial chiral nicotinamides were determined by X-ray structural analysis. The chirality could be controlled by the selection of enantiopure DBTA as a chiral auxiliary. The axial chirality generated by dynamic salt formation was retained for a long period after dissolving the chiral salt in solution even after removal of the chiral acid. The rate of racemization of nicotinamides could be controlled based on the temperature and solvent properties, and that of the salts was prolonged compared to free nicotinamides, as the molecular structure of the pyridinium ion in the salts was different from that of acid-free nicotinamides.

  5. Soluble salts: their incidence on the protection of metallic structures by paint coatings

    International Nuclear Information System (INIS)

    Morcillo, M.

    2003-01-01

    The presence of soluble salts at the metal/paint interface is known to have a detrimental effect on the integrity of most paint systems. Though this is a long-standing problem, it has recently come to receive greater attention from the protective coatings industry. In the paper the following points are reviewed: degradation mechanisms of the metal/paint system, the role of the metallic substrate, the nature, origin and detection os soluble salts, expected levels of soluble salts in practice, critical thresholds of soluble salts and risk levels for premature failures, role of the type and thickness of paint systems and exposure conditions, and prevention measures. The author presents an overview of the subject, making reference to the related research that has been carried out by him and his co-workers over the last 16 years. (Author) 58 refs

  6. An economic analysis of migration in Mexico.

    Science.gov (United States)

    Greenwood, M J; Ladman, J R

    1978-07-01

    This paper analyzes internal migration in Mexico over the 1960-70 period. A model of the determinants of migration is specified and estimated for aggregated interstate migration flows. Results show that distance serves as a significant deterrent to migration, that higher destination earning levels are attractive to migrants, and that regions with high unemployment rates experience lower rates of inmigration. An unanticipated finding is that regions with higher earning levels have greater rates of outmigration. The data are disaggregated to examine separate migration relationships for each state. The results are that distance is a lesser deterrent for those migrants with more accessible alternatives, that higher earning levels reduce the deterring effects of distance, and that regions with higher earning levels have lower associated elasticities of migration. It is concluded that economic factors have played a crucial role in internal migration and thus in the changing occupational and geographic structure of the Mexican labor force.

  7. Gender and Internal Migration dynamics in Ghana

    African Journals Online (AJOL)

    Agribotix GCS 068

    Internal migration is an inherent part of the processes of development and structural ... to rural-urban migrants by Government policies and strategies to enhance the ... Several studies globally indicate that migration is a driver of growth and an .... More recent approaches of networks theories and transnational approaches to ...

  8. 4D modeling of salt-sediment interactions during diapir evolution

    Energy Technology Data Exchange (ETDEWEB)

    Callot, J.P.; Rondon, D.; Letouzey, J. [IFP, Rueil Malmaison (France); Krajewski, P. [Gaz de France-PEG, Lingen (Germany); Rigollet, C. [Gaz de France, St. Denis la Plaine (France)

    2007-09-13

    We performed sand/silicon models imaged with X-ray tomography and reconstructed by 3D geomodelling for the study of (1) the interaction between host rock and salt diapir during diapir growth, and (2) the evolution of intra salt brittle rocks during diapir ascent. X-ray tomography is a non destructive imaging technique which allows us to follow the 4D evolution of the analogue model. Salt is modelled by Newtonian silicone putty and the internal rock layer, as well as the sedimentary host rock, by a granular Mohr-Coulomb material, generally coryndon. The analogue models are then compared to natural examples, the evolution of which is obtained through 3D restoration of the structures. (1) A 4D evolutionary scenario for a salt diapir development was originally proposed by Trusheim (1960) and discussed later on by Vendeville (1999) among others (Ge et al., 1997; Zirngast et al., 1996). This scenario is reproduced through analogue models to test the relative importance of (1) extensional tectonics, (2) sediment progradations, and (3) source layer depletion and rim-syncline touchdown, in the evolution of a diapir. The comparison of our results with the restored natural analogue shows that the main parameter remains (1) the rim-syncline touchdown and (2) the unloading of the diapir due to erosion. The latter accounts for a drop in strength necessary to allow for the flank rotation and down building of the diapir. Extensional stresses and sediment progradations will also amplify the halokinesis. (2) Salt diapirs from the Middle East or in Southern Permian Basin petroleum province show exotic blocks at outcrop and in salt mines, known as 'stringers' in subsurface data, usually composed of anhydrite, dolomite, marls or carbonates. These stringers, which constitute major structures inside the salt diapir, can reach a few km in size and originate from pre-existing brittle rock layers embedded in the salt layer. Stringers of the Ara carbonate within the Precambrian

  9. Metallic conductivity in a disordered charge-transfer salt derived from cis-BET-TTF

    Energy Technology Data Exchange (ETDEWEB)

    Rovira, C. [Inst. de Ciencia de Materials de Barcelona (CSIC) (Spain); Tarres, J. [Inst. de Ciencia de Materials de Barcelona (CSIC) (Spain); Ribera, E. [Inst. de Ciencia de Materials de Barcelona (CSIC) (Spain); Veciana, J. [Inst. de Ciencia de Materials de Barcelona (CSIC) (Spain); Canadell, E. [Inst. de Ciencia de Materials de Barcelona (CSIC) (Spain); Molins, E. [Inst. de Ciencia de Materials de Barcelona (CSIC) (Spain); Mas, M. [Inst. de Ciencia de Materials de Barcelona (CSIC) (Spain); Laukhin, V. [Inst. de Ciencia de Materials de Barcelona (CSIC) (Spain)]|[Rossijskaya Akademiya Nauk, Chernogolovka (Russian Federation). Inst. Khimicheskoj Fiziki; Doublet, M.L. [Lab. de Structure et Dynamique (CNRS), Univ. de Montpellier 2 (France); Cowan, D.O. [Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Chemistry; Yang, S. [Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Chemistry

    1997-02-28

    The first example of a metallic charge-transfer salt derived from cis-bis(ethylenethio)-tetrathiafulvalene (BET-TTF) is reported. (BET-TTF){sub 2}SCN and (BET-TTF)SCN salts were obtained by electrocrystallization starting from trans-BET-TTF. X-ray crystal structure of the mixed-valence salt revealed that trans-cis isomerization occurs upon one electron oxidation. In spite of the structural disorder in both BET-TTF and the counterion, 2:1 salt is metallic down to 60 K and then resistance increases slowly down to 4 K. (orig.)

  10. Pre-migration Trauma Exposure and Psychological Distress for Asian American Immigrants: Linking the Pre- and Post-migration Contexts.

    Science.gov (United States)

    Li, Miao; Anderson, James G

    2016-08-01

    Drawing on the life course perspective and the assumptive world theory, this paper examines whether pre-migration trauma exposure is associated with psychological distress through post-migration perceived discrimination for Asian American immigrants. The study is based on cross-sectional data from the National Latino and Asian American Study (N = 1639). Structural equation model is used to estimate the relationship between pre-migration trauma, post-migration perceived discrimination, and psychological distress. Additional models are estimated to explore possible variations across ethnic groups as well as across different types of pre-migration trauma experience. Pre-migration trauma exposure is associated with higher levels of psychological distress, both directly and indirectly through higher level of perceived discrimination, even after controlling for demographic/acculturative factors and post-migration trauma exposure. This pattern holds for the following sub-types of pre-migration trauma: political trauma, crime victimization, physical violence, accidental trauma, and relational trauma. Multi-group analyses show that this pattern holds for all Asian immigrant subgroups except the Vietnamese. Studies of immigrant mental health primarily focus on post-migration stressors. Few studies have considered the link between pre- and post-migration contexts in assessing mental health outcomes. The study illustrates the usefulness of bridging the pre- and post-migration context in identifying the mental health risks along the immigrant life course.

  11. 21 CFR 100.155 - Salt and iodized salt.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Salt and iodized salt. 100.155 Section 100.155 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION GENERAL Specific Administrative Rulings and Decisions § 100.155 Salt and iodized salt. (a) For the purposes of this section, the...

  12. Simulation of salt behavior using in situ response

    International Nuclear Information System (INIS)

    Li, W.T.

    1986-01-01

    The time-dependent nonlinear structural behavior in a salt formation around the openings can be obtained by either performing computational analysis of measuring in situ responses. However, analysis using laboratory test data may often deviate from the actual in situ conditions and geomechanical instruments can provide information only up to the time when the measurements were taken. A method has been suggested for simulating the salt behavior by utilizing the steady-state portion of in situ response history. Governing equations for computational analysis were normalized to the creep constant, the equations were solved, and the analytical response history was then computed in terms of normalized time. By synchronizing the response history obtained from the analysis to the one measured at the site, the creep constant was determined. Then the structural response of the salt was computed. This paper presents an improved method for simulating the salt behavior. In this method, the governing equations are normalized to the creep function, which represents the transient and the steady-state creep behavior. Both the transient and the steady-state portions of in situ response history are used in determining the creep function. Finally, a nonlinear mapping process relating the normalized and real time domains determines the behavior of the salt

  13. Plasticity of cell migration: a multiscale tuning model.

    NARCIS (Netherlands)

    Friedl, P.H.A.; Wolf, K. van der

    2010-01-01

    Cell migration underlies tissue formation, maintenance, and regeneration as well as pathological conditions such as cancer invasion. Structural and molecular determinants of both tissue environment and cell behavior define whether cells migrate individually (through amoeboid or mesenchymal modes) or

  14. Toxicity of road salt to Nova Scotia amphibians

    International Nuclear Information System (INIS)

    Collins, Sara J.; Russell, Ronald W.

    2009-01-01

    The deposition of chemical pollutants into roadside wetlands from runoff is a current environmental concern. In northern latitudes, a major pollutant in runoff water is salt (NaCl), used as de-icing agents. In this study, 26 roadside ponds were surveyed for amphibian species richness and chloride concentration. Acute toxicity tests (LC 50 ) were performed on five locally common amphibian species using a range of environmentally significant NaCl concentrations. Field surveys indicated that spotted salamanders (Ambystoma maculatum) and wood frogs (Rana sylvatica) did not occupy high chloride ponds. American toads (Bufo americanus) showed no pond preference based on chloride concentration. Acute toxicity tests showed spotted salamanders and wood frogs were most sensitive to chloride, and American toads were the least. Spring peepers (Pseudacris crucifer) and green frogs (Rana clamitans) showed intermediate sensitivities. We concluded that chloride concentrations in ponds due to application of de-icing salts, influenced community structure by excluding salt intolerant species. - Salt toxicity is presented as a mechanism affecting the distribution of amphibians and structure of amphibian communities in roadside wetlands

  15. Search efficiency of biased migration towards stationary or moving targets in heterogeneously structured environments

    Science.gov (United States)

    Azimzade, Youness; Mashaghi, Alireza

    2017-12-01

    Efficient search acts as a strong selective force in biological systems ranging from cellular populations to predator-prey systems. The search processes commonly involve finding a stationary or mobile target within a heterogeneously structured environment where obstacles limit migration. An open generic question is whether random or directionally biased motions or a combination of both provide an optimal search efficiency and how that depends on the motility and density of targets and obstacles. To address this question, we develop a simple model that involves a random walker searching for its targets in a heterogeneous medium of bond percolation square lattice and used mean first passage time (〈T 〉 ) as an indication of average search time. Our analysis reveals a dual effect of directional bias on the minimum value of 〈T 〉 . For a homogeneous medium, directionality always decreases 〈T 〉 and a pure directional migration (a ballistic motion) serves as the optimized strategy, while for a heterogeneous environment, we find that the optimized strategy involves a combination of directed and random migrations. The relative contribution of these modes is determined by the density of obstacles and motility of targets. Existence of randomness and motility of targets add to the efficiency of search. Our study reveals generic and simple rules that govern search efficiency. Our findings might find application in a number of areas including immunology, cell biology, ecology, and robotics.

  16. Statistical characteristics of dynamics for population migration driven by the economic interests

    Science.gov (United States)

    Huo, Jie; Wang, Xu-Ming; Zhao, Ning; Hao, Rui

    2016-06-01

    Population migration typically occurs under some constraints, which can deeply affect the structure of a society and some other related aspects. Therefore, it is critical to investigate the characteristics of population migration. Data from the China Statistical Yearbook indicate that the regional gross domestic product per capita relates to the population size via a linear or power-law relation. In addition, the distribution of population migration sizes or relative migration strength introduced here is dominated by a shifted power-law relation. To reveal the mechanism that creates the aforementioned distributions, a dynamic model is proposed based on the population migration rule that migration is facilitated by higher financial gains and abated by fewer employment opportunities at the destination, considering the migration cost as a function of the migration distance. The calculated results indicate that the distribution of the relative migration strength is governed by a shifted power-law relation, and that the distribution of migration distances is dominated by a truncated power-law relation. These results suggest the use of a power-law to fit a distribution may be not always suitable. Additionally, from the modeling framework, one can infer that it is the randomness and determinacy that jointly create the scaling characteristics of the distributions. The calculation also demonstrates that the network formed by active nodes, representing the immigration and emigration regions, usually evolves from an ordered state with a non-uniform structure to a disordered state with a uniform structure, which is evidenced by the increasing structural entropy.

  17. Towards an integrated model of international migration

    Directory of Open Access Journals (Sweden)

    Douglas S. MASSEY

    2012-12-01

    Full Text Available Demographers have yet to develop a suitable integrated model of international migration and consequently have been very poor at forecasting immigration. This paper outlines the basic elements of an integrated model and surveys recent history to suggest the key challenges to model construction. A comprehensive theory must explain the structural forces that create a supply of people prone to migrate internationally, the structural origins of labour demand in receiving countries, the motivations of those who respond to these forces by choosing to migrate internationally, the growth and structure of transnational networks that arise to support international movement, the behaviour states in response to immigrant flows, and the influence of state actions on the behaviour of migrants. Recent history suggests that a good model needs to respect the salience of markets, recognize the circularity of migrant flows, appreciate the power of feedback effects, and be alert unanticipated consequences of policy actions.

  18. Study on the phosphate reaction characteristics of lanthanide chlorides in molten salt with operating conditions

    International Nuclear Information System (INIS)

    Lee, Tae-Kyo; Hwang, Taek-Sung; Cho, Yung-Zun; Eun, Hee-Chul; Park, Hwan-Seo; Park, Geun-Il; Son, Sung-Mo

    2013-01-01

    A minimization of waste salt is one of the most important issues for the optimization of pyroprocessing. The separation of fission products in waste salts and the reuse of purified waste salt are promising strategies for minimizing the waste salt amounts. The phosphate precipitation of lanthanide is currently being considered for eutectic (LiCl–KCl) waste salt purification. In this research, the effects of molten salt temperature (400–550°C) and reaction time (max. 180 min) upon conversion into the phosphate of lanthanides was investigated using 1 and 3 kg of eutectic salt. The conversion efficiency of lanthanides to molten salt-insoluble precipitates and phosphates was increased with an increase in molten salt temperature and operating time until it attained a specific temperature and time. K 3 PO 4 as a precipitant was more favorable than Li 3 PO 4 in terms of reactivity. To obtain over a 99% overall conversion efficiency, about 30 min was required in the case of using K 3 PO 4 at 450°C, but about 120 min in the case of using Li 3 PO 4 at 550°C. The lanthanide precipitates formed by a reaction with phosphate were a mixture of monoclinic structures, usually representing a polyhedron structure, and a tetragonal structure, representing a platelet structure. (author)

  19. Hydrogeological research at the site of the Asse salt mine

    International Nuclear Information System (INIS)

    Batsche, H.; Rauert, W.; Klarr, K.

    1980-01-01

    In connection with the storage of radioactive wastes in the abandoned Asse salt mine near Brunswick (Federal Republic of Germany), the hydrogeology of the ridge of hills of Asse has been investigated. In order to obtain as detailed information as possible on the hydrogeological conditions, a long-term investigation programme has been set up and many methods of investigation have been used. Hydrogeological boring operations resulted in important scientific findings regarding, for example, the course of the salt table and the main anhydrite which towers up above the salt table into the overlying collapsed rocks. Hydrochemical data showed the hydraulic effect of transverse faults. Isotopic hydrological measurements permitted distinction between the flow behaviour of the groundwater in different aquifers. The origin of the salt springs at the northwest end of the structure can be explained. Some additional pumping and labelling tests are expected to yield quantitative results concerning hydraulic interrelationships recognized to date. The very complex hydrogeological structure of the ridge of hills of Asse is the result of the multiple succession of permeable and impermeable layers on the flanks of the structure, and, furthermore, is possibly due to the fact that in some individual faults groundwater may seep through normally impermeable layers as well as via waterways at the salt table. (author)

  20. Experiments and Modeling in Support of Generic Salt Repository Science

    International Nuclear Information System (INIS)

    Bourret, Suzanne Michelle; Stauffer, Philip H.; Weaver, Douglas James; Caporuscio, Florie Andre; Otto, Shawn; Boukhalfa, Hakim; Jordan, Amy B.; Chu, Shaoping; Zyvoloski, George Anthony; Johnson, Peter Jacob

    2017-01-01

    Salt is an attractive material for the disposition of heat generating nuclear waste (HGNW) because of its self-sealing, viscoplastic, and reconsolidation properties (Hansen and Leigh, 2012). The rate at which salt consolidates and the properties of the consolidated salt depend on the composition of the salt, including its content in accessory minerals and moisture, and the temperature under which consolidation occurs. Physicochemical processes, such as mineral hydration/dehydration salt dissolution and precipitation play a significant role in defining the rate of salt structure changes. Understanding the behavior of these complex processes is paramount when considering safe design for disposal of heat-generating nuclear waste (HGNW) in salt formations, so experimentation and modeling is underway to characterize these processes. This report presents experiments and simulations in support of the DOE-NE Used Fuel Disposition Campaign (UFDC) for development of drift-scale, in-situ field testing of HGNW in salt formations.

  1. Experiments and Modeling in Support of Generic Salt Repository Science

    Energy Technology Data Exchange (ETDEWEB)

    Bourret, Suzanne Michelle [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Stauffer, Philip H. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Weaver, Douglas James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Caporuscio, Florie Andre [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Otto, Shawn [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Boukhalfa, Hakim [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Jordan, Amy B. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Chu, Shaoping [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Zyvoloski, George Anthony [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Johnson, Peter Jacob [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-01-19

    Salt is an attractive material for the disposition of heat generating nuclear waste (HGNW) because of its self-sealing, viscoplastic, and reconsolidation properties (Hansen and Leigh, 2012). The rate at which salt consolidates and the properties of the consolidated salt depend on the composition of the salt, including its content in accessory minerals and moisture, and the temperature under which consolidation occurs. Physicochemical processes, such as mineral hydration/dehydration salt dissolution and precipitation play a significant role in defining the rate of salt structure changes. Understanding the behavior of these complex processes is paramount when considering safe design for disposal of heat-generating nuclear waste (HGNW) in salt formations, so experimentation and modeling is underway to characterize these processes. This report presents experiments and simulations in support of the DOE-NE Used Fuel Disposition Campaign (UFDC) for development of drift-scale, in-situ field testing of HGNW in salt formations.

  2. Eastern migrations vs western welfare states - (unbiased fears

    Directory of Open Access Journals (Sweden)

    Josifidis Kosta

    2013-01-01

    Full Text Available This inquiry considers some effects of migration on the labour markets and the welfare systems found in the EU-15, and from the perspectives of sustainability of the current welfare state regimes. Our inquiry aims to determine whether and to what extent different approaches in regulation of migration flows between the new and old member states are compatible with related economic and demographic findings. Within this context, our research considers regulations affecting migration flows. Our findings suggest that some effects of migration from the EU8+2 on the labour markets and social protection systems found in the EU-15, both with respect to level and structure, do indeed generate effects on migration, especially considering whether migration is based upon economic or welfare decisions. In addition, our inquiry considers perspectives upon restrictive versus liberal migration policies.

  3. Corrosion behaviour of selected high-level waste packaging materials under gamma irradiation and in-situ disposal conditions in rock salt

    International Nuclear Information System (INIS)

    Smailos, E.; Schwarzkopf, W.; Koester, R.

    1988-07-01

    Corrosion studies performed until now on a number of materials have shown that unalloyed steels, Hastelloy C4 and Ti 99.8-Pd are the most promising materials for a long-term resistant packaging to be used in high-level waste (HLW) canister disposal in rock salt formations. To characterize their corrosion behaviour in more detail, additional studies have been performed. The influence has been examined which is exerted by the gamma dose rate (1 Gy/h to 100 Gy/h) on the corrosion of three preselected steels and Hastelloy C4 at 90 0 C in a salt brine (Q-brine) rich in MgCl 2 , i.e., conditions relevant to accident scenarios in a repository. In addition, in-situ corrosion experiments have been carried out in the Asse salt mine at elevated temperatures (120 0 C to 210 0 C) in the absence and in the presence of a gamma radiation field of 3 x 10 2 Gy/h, within the framework of the German/US Brine Migration Test. Under the test conditions the gamma radiation did not exert a significant influence on the corrosion of the steels investigated, whereas Hastelloy C4, exposed to dose rates of 10 Gy/h and 100 Gy/h, underwent pitting and crevice corrosion (20 μm/a at the maximum).The low amounts of migrated salt brine (140 ml after 900 days) in the in-situ- experiment did not produce noticeable corrosion of the materials. (orig./RB) [de

  4. Labour migration and rural development in Egypt. A study of return migration in six villages.

    Science.gov (United States)

    Reichert, C

    1993-01-01

    An analysis of the impact of labor migration on social change in 6 rural villages (Shanawan and Kafr Shanawan north of Cairo, Kafr Yusuf and Tambul el Kubra near Simbalaween, and Abu Girg and Bani Walims in Minya governate) in Egypt was conducted in 1987-88. Since the 1991 Gulf war, the political environment, the labor markets, and the structure of migration opportunities have changed. An estimated 5% of rural households might have been directly affected by migrants' departure from Kuwait and Iraq. Data collection involved a household census survey of 8620 households, of which 2483 were migrants, including 1765 return migrants. A sample of return migrant (639) was interviewed about their migration experiences. Participant observation was also conducted among migrants and nonmigrants, and case studies were developed. Villages were demographically and socioeconomically very different; migration ranged from 18.5-434.2%. Structural change was measured on a scale of 1 to 6 in terms of population size, literacy of household heads, share of agricultural occupations, share of new red brick houses, and availability of infrastructural or institutional facilities. The probability of having a household with a migrant member increased with the rural character of the village. Landholdings or other major household variables were unrelated to migration. Rural outmigration was almost exclusively male, the average age was 29.6 years, and the average stay was 2.6 years. Migration destination was specific to individuals but affected by occupation and family or village resources. Professionals were overrepresented in Saudi Arabia, and farm and unskilled laborers or the unemployed were overrepresented in Iraq. Remittances from international migration have contributed along with the economic reforms of Sadat to new, private initiatives from all strata in rural society. 74.3% of returnees stated that improvement in income and living standards was the motivation for migration; many motives

  5. The association of estimated salt intake with blood pressure in a Viet Nam national survey.

    Directory of Open Access Journals (Sweden)

    Paul N Jensen

    Full Text Available To evaluate the association of salt consumption with blood pressure in Viet Nam, a developing country with a high level of salt consumption.Analysis of a nationally representative sample of Vietnamese adults 25-65 years of age who were surveyed using the World Health Organization STEPwise approach to Surveillance protocol. Participants who reported acute illness, pregnancy, or current use of antihypertensive medications were excluded. Daily salt consumption was estimated from fasting mid-morning spot urine samples. Associations of salt consumption with systolic blood pressure and prevalent hypertension were assessed using adjusted linear and generalized linear models. Interaction terms were tested to assess differences by age, smoking, alcohol consumption, and rural/urban status.The analysis included 2,333 participants (mean age: 37 years, 46% male, 33% urban. The average estimated salt consumption was 10g/day. No associations of salt consumption with blood pressure or prevalent hypertension were observed at a national scale in men or women. The associations did not differ in subgroups defined by age, smoking, or alcohol consumption; however, associations differed between urban and rural participants (p-value for interaction of urban/rural status with salt consumption, p = 0.02, suggesting that higher salt consumption may be associated with higher systolic blood pressure in urban residents but lower systolic blood pressure in rural residents.Although there was no evidence of an association at a national level, associations of salt consumption with blood pressure differed between urban and rural residents in Viet Nam. The reasons for this differential association are not clear, and given the large rate of rural to urban migration experienced in Viet Nam, this topic warrants further investigation.

  6. The association of estimated salt intake with blood pressure in a Viet Nam national survey.

    Science.gov (United States)

    Jensen, Paul N; Bao, Tran Quoc; Huong, Tran Thi Thanh; Heckbert, Susan R; Fitzpatrick, Annette L; LoGerfo, James P; Ngoc, Truong Le Van; Mokdad, Ali H

    2018-01-01

    To evaluate the association of salt consumption with blood pressure in Viet Nam, a developing country with a high level of salt consumption. Analysis of a nationally representative sample of Vietnamese adults 25-65 years of age who were surveyed using the World Health Organization STEPwise approach to Surveillance protocol. Participants who reported acute illness, pregnancy, or current use of antihypertensive medications were excluded. Daily salt consumption was estimated from fasting mid-morning spot urine samples. Associations of salt consumption with systolic blood pressure and prevalent hypertension were assessed using adjusted linear and generalized linear models. Interaction terms were tested to assess differences by age, smoking, alcohol consumption, and rural/urban status. The analysis included 2,333 participants (mean age: 37 years, 46% male, 33% urban). The average estimated salt consumption was 10g/day. No associations of salt consumption with blood pressure or prevalent hypertension were observed at a national scale in men or women. The associations did not differ in subgroups defined by age, smoking, or alcohol consumption; however, associations differed between urban and rural participants (p-value for interaction of urban/rural status with salt consumption, p = 0.02), suggesting that higher salt consumption may be associated with higher systolic blood pressure in urban residents but lower systolic blood pressure in rural residents. Although there was no evidence of an association at a national level, associations of salt consumption with blood pressure differed between urban and rural residents in Viet Nam. The reasons for this differential association are not clear, and given the large rate of rural to urban migration experienced in Viet Nam, this topic warrants further investigation.

  7. Some aspects of the development of NW-German salt domes

    International Nuclear Information System (INIS)

    Jaritz, W.

    1980-01-01

    Aspects of the development of salt structures that may be of some importance to the safety of a final disposal site for radioactive waste are salt ascent and salt dissolution at the surface. The geological history of the salt domes is described in terms of the dissolution of the salt at the dome surface. In many cases it can be distinguished whether dissolution was caused by the ascent of the salt into strata containing groundwater by diapirism or by epeirogenic uplift or both. The salt domes of Wesendorf, Heide, and Marne are used as examples in a discussion of the transition from dissolution to the deposition of a cover of impermeable sediments. Moreover, the development of the Gorleben salt dome is described. The author's studies show the average rate of uplift of the NW-German salt domes in the diapiric stage to have ranged from a little less than 0.1 to about 0.5 mm per year. For salt domes in later stages, the rate of uplift is several hundredths of a millimeter per year at most. (orig.) [de

  8. The migration game in habitat network: the case of tuna

    DEFF Research Database (Denmark)

    Mariani, Patrizio; Krivan, Vlastimil; MacKenzie, Brian

    2016-01-01

    migration in direction of increasing fitness should lead to the ideal free distribution (IFD) which is the evolutionary stable strategy of the habitat selection game. We introduce a migration game which focuses on migrating dynamics leading to the IFD for age-structured populations and in time varying...

  9. Atomic Resolution Structural and Chemical Imaging Revealing the Sequential Migration of Ni, Co, and Mn upon the Battery Cycling of Layered Cathode

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Pengfei; Zheng, Jianming; Zhang, Ji-Guang; Wang, Chongmin

    2017-05-11

    Layered lithium transition metal oxides (LTMO) are promising candidate cathode materials for next generation high energy density lithium ion battery. The challenge for using this category of cathode is the capacity and voltage fading, which is believed to be associated with the layered structure disordering, a process that is initiated from the surface or solid-electrolyte interface and facilitated by transition metal (TM) reduction and oxygen vacancy formation. However, the atomic level dynamic mechanism of such a layered structure disordering is still not fully clear. In this work, utilizing atomic resolution electron energy loss spectroscopy (EELS), we map, for the first time at atomic scale, the spatial evolution of Ni, Co and Mn in a cycled LiNi1/3M1/3Co1/3O2 layered cathode. In combination with atomic level structural imaging, we discovered the direct correlation of TM ions migration behavior with lattice disordering, featuring the residing of TM ions in the tetrahedral site and a sequential migration of Ni, Co, and Mn upon the increased lattice disordering of the layered structure. This work highlights that Ni ions, though acting as the dominant redox species in many LTMO, are labile to migrate to cause lattice disordering upon battery cycling; while the Mn ions are more stable as compared with Ni and Co and can act as pillar to stabilize layered structure. Direct visualization of the behavior of TM ions during the battery cycling provides insight for designing of cathode with structural stability and correspondingly a superior performance.

  10. Polydimethylsiloxane-polymethacrylate block copolymers tethering quaternary ammonium salt groups for antimicrobial coating

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Xiaoshuai; Li, Yancai; Zhou, Fang; Ren, Lixia; Zhao, Yunhui, E-mail: zhaoyunhui@tju.edu.cn; Yuan, Xiaoyan

    2015-02-15

    Highlights: • A series of PDMS-b-QPDMAEMA block copolymers were synthesized via RAFT polymerization. • The composition and morphology of the copolymer films strongly depended on the content of QPDMAEMA. • Migration of QPDMAEMA blocks toward surface was promoted when contacting with water. • Heterogeneous film surfaces with higher N{sup +} content exhibited more obvious antimicrobial activity. - Abstract: Block copolymers PDMS-b-PDMAEMA were synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization involving N,N-dimethylaminoethyl methacrylate (DMAEMA) by using poly(dimethylsiloxane) (PDMS) macro-chain transfer agent. And, the tertiary amino groups in PDMAEMA were quaternized with n-octyliodide to provide quaternary ammonium salts (QPDMAEMA). The well-defined copolymers generated composition variation and morphology evolvement on film surfaces, which were characterized by X-ray photoelectron spectroscopy, atomic force microscopy, and contact angle measurements. The results indicated that the enrichment of QPDMAEMA brought about lower elemental ratios of Si/N on the film surfaces. The surface morphologies evolved with the variations of QPDMAEMA content, and the variation trend of film roughness was exactly opposite to that of water contact angle hysteresis. With regard to structure-antimicrobial relationships, the copolymer films had more evident antimicrobial activity against Gram-positive, Bacillus subtilis, and the surfaces with heterogeneous morphology and higher N{sup +} content presented better antimicrobial activity. The functionalized copolymers based PDMS and quaternary ammonium salts materials have the potential applications as antimicrobial coatings.

  11. Salt effects on ionization equilibria of histidines in myoglobin.

    Science.gov (United States)

    Kao, Y H; Fitch, C A; Bhattacharya, S; Sarkisian, C J; Lecomte, J T; García-Moreno E, B

    2000-09-01

    The salt dependence of histidine pK(a) values in sperm whale and horse myoglobin and in histidine-containing peptides was measured by (1)H-NMR spectroscopy. Structure-based pK(a) calculations were performed with continuum methods to test their ability to capture the effects of solution conditions on pK(a) values. The measured pK(a) of most histidines, whether in the protein or in model compounds, increased by 0.3 pH units or more between 0.02 M and 1.5 M NaCl. In myoglobin two histidines (His(48) and His(36)) exhibited a shallower dependence than the average, and one (His(113)) showed a steeper dependence. The (1)H-NMR data suggested that the salt dependence of histidine pK(a) values in the protein was determined primarily by the preferential stabilization of the charged form of histidine with increasing salt concentrations rather than by screening of electrostatic interactions. The magnitude and salt dependence of interactions between ionizable groups were exaggerated in pK(a) calculations with the finite-difference Poisson-Boltzmann method applied to a static structure, even when the protein interior was treated with arbitrarily high dielectric constants. Improvements in continuum methods for calculating salt effects on pK(a) values will require explicit consideration of the salt dependence of model compound pK(a) values used for reference in the calculations.

  12. Febuxostat-Minoxidil Salt Solvates: Crystal Structures, Characterization, Interconversion and Solubility Performance

    Directory of Open Access Journals (Sweden)

    Li-Yang Li

    2018-02-01

    Full Text Available Three febuxostat-minoxidil salt solvates with acetone (ACE, tetrahydrofuran (THF and isopropanol (IPA are synthesized by solvent-assisted grinding and characterized by infrared (IR, nuclear magnetic resonance (1H-NMR, single crystal and powder X-ray diffraction (PXRD, thermogravimetry (TG and differential scanning calorimetry (DSC. These febuxostat-minoxidil salt solvates feature isostructural with the same stoichiometries (1:1:1 molecule ratio. The proton transfers from the carboxylic group of febuxostat (FEB to imino N atom of minoxidil (MIN, which forms the motif with combined R 2 2 (9 R 4 2 (8 R 2 2 (9 graph set in the three solvates. The solvents occupy the different positions related to the motif, which results in the apparent differences in PXRD patterns before/after desolvation although they are isostructures. The FEB-MIN·THF was more thermostable than FEB-MIN·ACE and FEB-MIN·IPA relative to solvent removal from DSC patterns, which is different from the results from the solvent-exchange experiments in chemical kinetics. All three salt solvates exhibit increased equilibrium solubility compared to FEB in aqueous medium.

  13. Migration, Gender and Social Justice : Connecting Research and ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Migration, Gender and Social Justice : Connecting Research and Practice Networks. Gender equality in migration as a policy objective requires an understanding of the intersections between different power structures (gender, class, ethnicity and age) and how they produce different experiences with regard to identity ...

  14. Multisource Least-squares Reverse Time Migration

    KAUST Repository

    Dai, Wei

    2012-12-01

    Least-squares migration has been shown to be able to produce high quality migration images, but its computational cost is considered to be too high for practical imaging. In this dissertation, a multisource least-squares reverse time migration algorithm (LSRTM) is proposed to increase by up to 10 times the computational efficiency by utilizing the blended sources processing technique. There are three main chapters in this dissertation. In Chapter 2, the multisource LSRTM algorithm is implemented with random time-shift and random source polarity encoding functions. Numerical tests on the 2D HESS VTI data show that the multisource LSRTM algorithm suppresses migration artifacts, balances the amplitudes, improves image resolution, and reduces crosstalk noise associated with the blended shot gathers. For this example, multisource LSRTM is about three times faster than the conventional RTM method. For the 3D example of the SEG/EAGE salt model, with comparable computational cost, multisource LSRTM produces images with more accurate amplitudes, better spatial resolution, and fewer migration artifacts compared to conventional RTM. The empirical results suggest that the multisource LSRTM can produce more accurate reflectivity images than conventional RTM does with similar or less computational cost. The caveat is that LSRTM image is sensitive to large errors in the migration velocity model. In Chapter 3, the multisource LSRTM algorithm is implemented with frequency selection encoding strategy and applied to marine streamer data, for which traditional random encoding functions are not applicable. The frequency-selection encoding functions are delta functions in the frequency domain, so that all the encoded shots have unique non-overlapping frequency content. Therefore, the receivers can distinguish the wavefield from each shot according to the frequencies. With the frequency-selection encoding method, the computational efficiency of LSRTM is increased so that its cost is

  15. Boric Ester-Type Molten Salt via Dehydrocoupling Reaction

    Directory of Open Access Journals (Sweden)

    Noriyoshi Matsumi

    2014-11-01

    Full Text Available Novel boric ester-type molten salt was prepared using 1-(2-hydroxyethyl-3-methylimidazolium chloride as a key starting material. After an ion exchange reaction of 1-(2-hydroxyethyl-3-methylimidazolium chloride with lithium (bis-(trifluoromethanesulfonyl imide (LiNTf2, the resulting 1-(2-hydroxyethyl-3-methylimidazolium NTf2 was reacted with 9-borabicyclo[3.3.1]nonane (9-BBN to give the desired boric ester-type molten salt in a moderate yield. The structure of the boric ester-type molten salt was supported by 1H-, 13C-, 11B- and 19F-NMR spectra. In the presence of two different kinds of lithium salts, the matrices showed an ionic conductivity in the range of 1.1 × 10−4–1.6 × 10−5 S cm−1 at 51 °C. This was higher than other organoboron molten salts ever reported.

  16. Kink structures induced in nickel-based single crystal superalloys by high-Z element migration

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Fei; Zhang, Jianxin [Key Laboratory for Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Mao, Shengcheng [Institute of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing 100124 (China); Jiang, Ying [Center of Electron Microscopy and State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Feng, Qiang [National Center for Materials Service Safety, University of Science and Technology Beijing, Beijing 100083 (China); State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Shen, Zhenju; Li, Jixue; Zhang, Ze [Center of Electron Microscopy and State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Han, Xiaodong [Institute of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing 100124 (China)

    2015-01-05

    Highlights: • Innovative kink structures generate at the γ/γ′ interfaces in the crept superalloy. • Clusters of heavy elements congregate at the apex of the kinks. • Dislocation core absorbs hexagonal structural high-Z elements. - Abstract: Here, we investigate a new type of kink structure that is found at γ/γ′ interfaces in nickel-based single crystal superalloys. We studied these structures at the atomic and elemental level using aberration corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). The core of the dislocation absorbs high-Z elements (i.e., Co and Re) that adopt hexagonal arrangements, and it extrudes elements (i.e., Ni and Al) that adopt face centered cubic (fcc) structures. High-Z elements (i.e., Ta and W) and Cr, which is a low-Z element, are stabilized in body centered cubic (bcc) arrangements; Cr tends to behave like Re. High-Z elements, which migrate and adopt a hexagonal structure, induce kink formation at γ/γ′ interfaces. This process must be analyzed to fully understand the kinetics and dynamics of creep in nickel-based single crystal superalloys.

  17. Preliminary investigation results as applied to utilization of Ukrainian salt formations for disposal of high-level radioactive waste

    International Nuclear Information System (INIS)

    Shekhunova, S.B.; Khrushchov, D.P.; Petrichenko, O.I.

    1994-01-01

    The salt-bearing formations have been investigated in five regions of Ukraine. Upper Devonian and Lower Permian evaporite formations in Dnieper-Donets Depression and in the NW part of Donets basin are considered to be promising for disposal of high-level radioactive waste (HLRW). Rock salt occurs there either as bedded salts or as salt pillows and salt diapirs. Preliminary studies have resulted in selection of several candidate sites that show promise for construction of a subsurface pilot lab. Ten salt domes and two sites in bedded salts have been proposed for further exploration. Based on microstructural studies it is possible to separate the body of a salt structure and to locate within its limits the rock salt structure and to locate within its limits the rock salt blocks of different genesis, i.e.: (a) blocks characteristic of initial undisturbed sedimentary structure; (b) flow zones; (c) sliding planes; (d) bodies of loose or uncompacted rock salt. Ultramicrochemical examination of inclusions in halite have shown that they are composed of more than 40 minerals. It is emphasized that to assess suitability of a structure for construction of subsurface lab, and also the potential construction depth intervals, account should be taken of the results of ultra microchemical and microstructural data

  18. Evolution of cooperation among game players with non-uniform migration scopes

    NARCIS (Netherlands)

    Zhang, Chunyan; Zhang, Jianlei; Xie, Guangming

    In social dilemmas, cooperation among randomly interacting individuals is often hard to achieve. The situation changes if migration takes place, where game structure jointly evolves with the migration from adverse neighborhoods. Here we introduce a framework combining migration with the individual

  19. Thin- and thick-skinned salt tectonics in the Netherlands: a quantitative approach

    NARCIS (Netherlands)

    Veen, J.H. ten; Gessel, S.F. van; Dulk, M. den

    2012-01-01

    The Zechstein salt in the Dutch part of the North Sea Basin played a key role in the generation of successful petroleum plays. This is not only because of its sealing capacity, but also because the salt occurs in structures that provide lateral and vertical traps. The structural styles of areas with

  20. A personality theory of U.S. migration geography.

    Science.gov (United States)

    Stetzer, F C

    1985-01-01

    "Neoclassical models of migration fail to account adequately for individual differences in propensity to migrate, rates of emigration from states and cities, and the generally high rates of population circulation common in the United States. This article proposes that migration propensity is related to an individual's personality. Using the facts that personality traits are generationally regenerative, both through inheritance and culture, and that the United States was settled in a series of migration waves from east to west, this theory predicts a spatial structuring of emigration rates which closely correspond to actual rates for states and major cities." excerpt

  1. DEFINING HUMAN MIGRATION – A POLICY MAKERS PERSPECTIVE

    Directory of Open Access Journals (Sweden)

    Paul-Panfil IVAN

    2015-06-01

    Full Text Available Migration is a global phenomenon gradually increased in scope, impact and complexity. Practically all countries are simultaneously countries of destination, origin and transit for migrants. Traditionally migration flows are complemented by new changes generated by economic, demographic, political or social conditions, and these trends affect both the size and structure of the migrant population and also economies and societies. Of course this has sparked international interest from various NGOs and by the European Union and the United Nations. This paper aims to present the vision of international organizations concerned with migration and how they define migration and its typologies.

  2. Intimate partner violence and forced migration during pregnancy: Structural constraints to women's agency.

    Science.gov (United States)

    Turan, Janet M; Hatcher, Abigail M; Romito, Patrizia; Mangone, Emily; Durojaiye, Modupeoluwa; Odero, Merab; Camlin, Carol S

    2016-01-01

    Little is known about migration during pregnancy related to intimate partner violence (IPV). In this paper, we examine issues of agency in relation to pregnant women's migrations in a high HIV prevalence area of Kenya. We qualitatively explored forced migration among pregnant women, using data from in-depth interviews, focus groups and IPV screening forms. To quantitatively examine migration during pregnancy, we analysed data from a prospective study of 614 pregnant women. The qualitative data revealed that women had varied responses to violence in pregnancy, with some being able to leave the marital home voluntarily as a strategy to escape violence. Others were 'sent packing' from their marital homes when they dared to exercise autonomy, in some cases related to HIV status. Quantitative analyses revealed that pregnant women who migrated were more educated, less likely to be living with a partner and had fewer children than other women. Migration among pregnant women in Kenya illustrates the complexity of understanding women's agency in the context of IPV. The findings indicate that there is not a dichotomy between 'victim' and 'agent', but rather a complex dynamic between and within pregnant women, who may sequentially or simultaneously experience aspects of victimhood and/or agentic response.

  3. Mental health of newly arrived Burmese refugees in Australia: contributions of pre-migration and post-migration experience.

    Science.gov (United States)

    Schweitzer, Robert D; Brough, Mark; Vromans, Lyn; Asic-Kobe, Mary

    2011-04-01

    This study documents the mental health status of people from Burmese refugee backgrounds recently arrived in Australia, then examines the contributions of gender, pre-migration and post-migration factors in predicting mental health. Structured interviews, including a demographic questionnaire, the Harvard Trauma Questionnaire, the Post-migration Living Difficulties Checklist and Hopkins Symptom Checklist assessed pre-migration trauma, post-migration living difficulties, depression, anxiety, somatization and traumatization symptoms in a sample of 70 adults across five Burmese ethnic groups. Substantial proportions of participants reported psychological distress in symptomatic ranges including: post-traumatic stress disorder (9%), anxiety (20%) and depression (36%), as well as significant symptoms of somatization (37%). Participants reported multiple and severe pre-migration traumas. Post-migration living difficulties of greatest concern included communication problems and worry about family not in Australia. Gender did not predict mental health. Level of exposure to traumatic events and post-migration living difficulties each made unique and relatively equal contributions to traumatization symptoms. Post-migration living difficulties made unique contributions to depression, anxiety and somatization symptoms. While exposure to traumatic events impacted on participants' mental well-being, post-migration living difficulties had greater salience in predicting mental health outcomes of people from Burmese refugee backgrounds. Reported rates of post-traumatic stress disorder symptoms were consistent with a large review of adults across seven western countries. High levels of somatization point to a nuanced expression of distress. Findings have implications for service provision in terms of implementing appropriate interventions to effectively meet the needs of this newly arrived group in Australia.

  4. Urban squatting and migration in Peninsular Malaysia.

    Science.gov (United States)

    Johnstone, M

    1983-01-01

    "This article examines some of the links between the phenomena of urban migration and squatter settlements in the Third World city. This will be done by demonstrating that both are outcomes of fundamental social and political forces that have operated on these societies. Migration and squatting are placed in a context of the historical processes that led to the uneven development of Malaysia. The article offers some explanation for the origin of the inequalities observed in spatial structures--in this case urban housing--by focusing on one of the contributory factors, namely migration." excerpt

  5. Improved Design and Fabrication of Hydrated-Salt Pills

    Science.gov (United States)

    Shirron, Peter J.; DiPirro, Michael J.; Canavan, Edgar R.

    2011-01-01

    A high-performance design, and fabrication and growth processes to implement the design, have been devised for encapsulating a hydrated salt in a container that both protects the salt and provides thermal conductance between the salt and the environment surrounding the container. The unitary salt/container structure is known in the art as a salt pill. In the original application of the present design and processes, the salt is, more specifically, a hydrated paramagnetic salt, for use as a refrigerant in a very-low-temperature adiabatic demagnetization refrigerator (ADR). The design and process can also be applied, with modifications, to other hydrated salts. Hydrated paramagnetic salts have long been used in ADRs because they have the desired magnetic properties at low temperatures. They also have some properties, disadvantageous for ADRs, that dictate the kind of enclosures in which they must be housed: Being hydrated, they lose water if exposed to less than 100-percent relative humidity. Because any dehydration compromises their magnetic properties, salts used in ADRs must be sealed in hermetic containers. Because they have relatively poor thermal conductivities in the temperature range of interest (<0.1 K), integral thermal buses are needed as means of efficiently transferring heat to and from the salts during refrigeration cycles. A thermal bus is typically made from a high-thermal-conductivity met al (such as copper or gold), and the salt is configured to make intimate thermal contact with the metal. Commonly in current practice (and in the present design), the thermal bus includes a matrix of wires or rods, and the salt is grown onto this matrix. The density and spacing of the conductors depend on the heat fluxes that must be accommodated during operation.

  6. Genetic structuring and migration patterns of Atlantic bigeye tuna, Thunnus obesus (Lowe, 1839

    Directory of Open Access Journals (Sweden)

    Beerli Peter

    2008-09-01

    Full Text Available Abstract Background Large pelagic fishes are generally thought to have little population genetic structuring based on their cosmopolitan distribution, large population sizes and high dispersal capacities. However, gene flow can be influenced by ecological (e.g. homing behaviour and physical (e.g. present-day ocean currents, past changes in sea temperature and levels factors. In this regard, Atlantic bigeye tuna shows an interesting genetic structuring pattern with two highly divergent mitochondrial clades (Clades I and II, which are assumed to have been originated during the last Pleistocene glacial maxima. We assess genetic structure patterns of Atlantic bigeye tuna at the nuclear level, and compare them with mitochondrial evidence. Results We examined allele size variation of nine microsatellite loci in 380 individuals from the Gulf of Guinea, Canary, Azores, Canada, Indian Ocean, and Pacific Ocean. To investigate temporal stability of genetic structure, three Atlantic Ocean sites were re-sampled a second year. Hierarchical AMOVA tests, RST pairwise comparisons, isolation by distance (Mantel tests, Bayesian clustering analyses, and coalescence-based migration rate inferences supported unrestricted gene flow within the Atlantic Ocean at the nuclear level, and therefore interbreeding between individuals belonging to both mitochondrial clades. Moreover, departures from HWE in several loci were inferred for the samples of Guinea, and attributed to a Wahlund effect supporting the role of this region as a spawning and nursery area. Our microsatellite data supported a single worldwide panmictic unit for bigeye tunas. Despite the strong Agulhas Current, immigration rates seem to be higher from the Atlantic Ocean into the Indo-Pacific Ocean, but the actual number of individuals moving per generation is relatively low compared to the large population sizes inhabiting each ocean basin. Conclusion Lack of congruence between mt and nuclear evidences, which

  7. Genetic structuring and migration patterns of Atlantic bigeye tuna, Thunnus obesus (Lowe, 1839).

    Science.gov (United States)

    Gonzalez, Elena G; Beerli, Peter; Zardoya, Rafael

    2008-09-17

    Large pelagic fishes are generally thought to have little population genetic structuring based on their cosmopolitan distribution, large population sizes and high dispersal capacities. However, gene flow can be influenced by ecological (e.g. homing behaviour) and physical (e.g. present-day ocean currents, past changes in sea temperature and levels) factors. In this regard, Atlantic bigeye tuna shows an interesting genetic structuring pattern with two highly divergent mitochondrial clades (Clades I and II), which are assumed to have been originated during the last Pleistocene glacial maxima. We assess genetic structure patterns of Atlantic bigeye tuna at the nuclear level, and compare them with mitochondrial evidence. We examined allele size variation of nine microsatellite loci in 380 individuals from the Gulf of Guinea, Canary, Azores, Canada, Indian Ocean, and Pacific Ocean. To investigate temporal stability of genetic structure, three Atlantic Ocean sites were re-sampled a second year. Hierarchical AMOVA tests, RST pairwise comparisons, isolation by distance (Mantel) tests, Bayesian clustering analyses, and coalescence-based migration rate inferences supported unrestricted gene flow within the Atlantic Ocean at the nuclear level, and therefore interbreeding between individuals belonging to both mitochondrial clades. Moreover, departures from HWE in several loci were inferred for the samples of Guinea, and attributed to a Wahlund effect supporting the role of this region as a spawning and nursery area. Our microsatellite data supported a single worldwide panmictic unit for bigeye tunas. Despite the strong Agulhas Current, immigration rates seem to be higher from the Atlantic Ocean into the Indo-Pacific Ocean, but the actual number of individuals moving per generation is relatively low compared to the large population sizes inhabiting each ocean basin. Lack of congruence between mt and nuclear evidences, which is also found in other species, most likely reflects

  8. Salt-assisted and salt-suppressed sol-gel transitions of methylcellulose in water.

    Science.gov (United States)

    Xu, Y; Wang, C; Tam, K C; Li, L

    2004-02-03

    The effects of various salts on the sol-gel transition of aqueous methylcellulose (MC) solutions have been studied systematically by means of a micro differential scanning calorimeter. It was found that the heating process was endothermic while the cooling process was exothermic for both MC solutions with and without salts. The addition of salts did not change the patterns of gelation and degelation of MC. However, the salts could shift the sol-gel transition and the gel-sol transition to lower or higher temperatures from a pure MC solution, depending on the salt type. These opposite effects were termed the salt-assisted and salt-suppressed sol-gel transitions. Either the salt-assisted transition or the salt-suppressed sol-gel transition was a function of salt concentration. In addition, each salt was found to have its own concentration limit for producing a stable aqueous solution of MC at a given concentration of MC, which was related to the anionic charge density of the salt. Cations were proved to have weaker effects than anions. The "salt-out strength", defined as the salt effect per mole of anion, was obtained for each anion studied. The thermodynamic mechanisms involved in the salt-assisted and salt-suppressed sol-gel transitions are discussed.

  9. Enrichment of fission products in ionic salt bath by countercurrent electromigration

    International Nuclear Information System (INIS)

    Matsuura, Haruaki; Takagi, Ryuzo; Okada, Isao; Fujita, Reiko.

    1997-01-01

    We have proposed to apply a countercurrent electromigration method to enrichment of fission products in ionic melts. In the test runs, for this purpose, we have enriched Cs, Sr and Gd from their dilute melts. All of Cs, Sr and Gd were much concentrated at the area near the anode in the migration tubes. Gd and Sr were more concentrated than Cs. It was found that the electromigration method can be applied to the salt bath refleshing process after an electrorefining process, which removes fission products of multivalent cations. (author)

  10. Environmental Constraints Guide Migration of Malaria Parasites during Transmission

    Science.gov (United States)

    Hellmann, Janina Kristin; Münter, Sylvia; Kudryashev, Mikhail; Schulz, Simon; Heiss, Kirsten; Müller, Ann-Kristin; Matuschewski, Kai; Spatz, Joachim P.; Schwarz, Ulrich S.; Frischknecht, Friedrich

    2011-01-01

    Migrating cells are guided in complex environments mainly by chemotaxis or structural cues presented by the surrounding tissue. During transmission of malaria, parasite motility in the skin is important for Plasmodium sporozoites to reach the blood circulation. Here we show that sporozoite migration varies in different skin environments the parasite encounters at the arbitrary sites of the mosquito bite. In order to systematically examine how sporozoite migration depends on the structure of the environment, we studied it in micro-fabricated obstacle arrays. The trajectories observed in vivo and in vitro closely resemble each other suggesting that structural constraints can be sufficient to guide Plasmodium sporozoites in complex environments. Sporozoite speed in different environments is optimized for migration and correlates with persistence length and dispersal. However, this correlation breaks down in mutant sporozoites that show adhesion impairment due to the lack of TRAP-like protein (TLP) on their surfaces. This may explain their delay in infecting the host. The flexibility of sporozoite adaption to different environments and a favorable speed for optimal dispersal ensures efficient host switching during malaria transmission. PMID:21698220

  11. International Elderly Migration in Hungary

    Directory of Open Access Journals (Sweden)

    Sándor Illés

    2006-06-01

    Full Text Available The paper examines international elderly migration (IEM related to Hungary. Little effort has been made to investigate this increasingly important element of human migration in Central and Eastern Europe. The general objective of this study is to contribute to filling this gap. IEM is investigated using register-based data on migration flows, stocks and citizenship statistics. The analysis focuses on the time series but the paper also considers the historical context and the recent patterns of IEM. The aim of the research was fourfold. Firstly, we tried to establish when IEM related to Hungary began. Secondly, we detected the accelerating character of this phenomenon. Thirdly, we were able to identify the main macrofactors influencing the level of IEM. Fourthly, the main result of the study was that it allowed exploration of a Hungarian peculiarity. “Pension seeking” is one very distinctive feature of IEM and is in many ways a legacy of the state socialism period. Therefore, its emergence on such a large scale is the result of the transformation period. We suppose that pension-hunting type migration will be temporary in nature. Conclusions about the motivational structure of IEM are discussed with reference to policy implications in the light of the ageing population structure in Hungary.

  12. High Spatial resolution remote sensing for salt marsh change detection on Fire Island National Seashore

    Science.gov (United States)

    Campbell, A.; Wang, Y.

    2017-12-01

    Salt marshes are under increasing pressure due to anthropogenic stressors including sea level rise, nutrient enrichment, herbivory and disturbances. Salt marsh losses risk the important ecosystem services they provide including biodiversity, water filtration, wave attenuation, and carbon sequestration. This study determines salt marsh change on Fire Island National Seashore, a barrier island along the south shore of Long Island, New York. Object-based image analysis was used to classifying Worldview-2, high resolution satellite, and topobathymetric LiDAR. The site was impacted by Hurricane Sandy in October of 2012 causing a breach in the Barrier Island and extensive overwash. In situ training data from vegetation plots were used to train the Random Forest classifier. The object-based Worldview-2 classification achieved an overall classification accuracy of 92.75. Salt marsh change for the study site was determined by comparing the 2015 classification with a 1997 classification. The study found a shift from high marsh to low marsh and a reduction in Phragmites on Fire Island. Vegetation losses were observed along the edge of the marsh and in the marsh interior. The analysis agreed with many of the trends found throughout the region including the reduction of high marsh and decline of salt marsh. The reduction in Phragmites could be due to the species shrinking niche between rising seas and dune vegetation on barrier islands. The complex management issues facing salt marsh across the United States including sea level rise and eutrophication necessitate very high resolution classification and change detection of salt marsh to inform management decisions such as restoration, salt marsh migration, and nutrient inputs.

  13. Structural and electronic properties of TiX (X=N, As) in rock salt and zinc blende phase: A DFT study

    Energy Technology Data Exchange (ETDEWEB)

    Verma, U. P.; Nayak, V. [School of Studies in Phyics, jiwaji University, Gwalior-474011 (India)

    2016-05-23

    Quantum mechanical first principle calculations have been performed to study the electronic and structural properties of TiN and TiAs in zinc blende (ZB) and rock salt (RS) structures. The full-potential linearized augmented plane wave (FP-LAPW) method has been used within the framework of density functional theory (DFT). The exchange correlation functional has been solved employing generalized gradient approximation (GGA). Our predicted results for lattice constants are in good agreement with the earlier findings. The electronic band structures of TiX are metallic in both the phases.

  14. Where Does Road Salt Go - a Static Salt Model

    Science.gov (United States)

    Yu, C. W.; Liu, F.; Moriarty, V. W.

    2017-12-01

    Each winter, more than 15 million tons of road salt is applied in the United States for the de-icing purpose. Considerable amount of chloride in road salt flows into streams/drainage systems with the snow melt runoff and spring storms, and eventually goes into ecologically sensitive low-lying areas in the watershed, such as ponds and lakes. In many watersheds in the northern part of US, the chloride level in the water body has increased significantly in the past decades, and continues an upward trend. The environmental and ecological impact of the elevated chloride level can no longer be ignored. However although there are many studies on the biological impact of elevated chloride levels, there are few investigations on how the spatially distributed road salt application affects various parts of the watershed. In this presentation, we propose a static road salt model as a first-order metric to address spacial distribution of salt loading. Derived from the Topological Wetness Index (TWI) in many hydrological models, this static salt model provides a spatial impact as- sessment of road salt applications. To demonstrate the effectiveness of the static model, National Elevation Dataset (NED) of ten-meter resolution of Lake George watershed in New York State is used to generate the TWI, which is used to compute a spatially dis- tributed "salt-loading coefficient" of the whole watershed. Spatially varying salt applica- tion rate is then aggregated, using the salt-loading coefficients as weights, to provide salt loading assessments of streams in the watershed. Time-aggregated data from five CTD (conductivity-temperature-depth) sensors in selected streams are used for calibration. The model outputs and the sensor data demonstrate a strong linear correlation, with the R value of 0.97. The investigation shows that the static modeling approach may provide an effective method for the understanding the input and transport of road salt to within watersheds.

  15. Incorporating future change into current conservation planning: Evaluating tidal saline wetland migration along the U.S. Gulf of Mexico coast under alternative sea-level rise and urbanization scenarios

    Science.gov (United States)

    Enwright, Nicholas M.; Griffith, Kereen T.; Osland, Michael J.

    2015-11-02

    In this study, the U.S. Geological Survey, in cooperation with the U.S. Fish and Wildlife Service, quantified the potential for landward migration of tidal saline wetlands along the U.S. Gulf of Mexico coast under alternative future sea-level rise and urbanization scenarios. Our analyses focused exclusively on tidal saline wetlands (that is, mangrove forests, salt marshes, and salt flats), and we combined these diverse tidal saline wetland ecosystems into a single grouping, “tidal saline wetland.” Collectively, our approach and findings can provide useful information for scientists and environmental planners working to develop future-focused adaptation strategies for conserving coastal landscapes and the ecosystem goods and services provided by tidal saline wetlands. The primary product of this work is a public dataset that identifies locations where landward migration of tidal saline wetlands is expected to occur under alternative future sea-level rise and urbanization scenarios. In addition to identifying areas where landward migration of tidal saline wetlands is possible because of the absence of barriers, these data also identify locations where landward migration of these wetlands could be prevented by barriers associated with current urbanization, future urbanization, and levees.

  16. Resolving ultrafast exciton migration in organic solids at the nanoscale

    Science.gov (United States)

    Ginsberg, Naomi

    The migration of Frenkel excitons, tightly-bound electron-hole pairs, in photosynthesis and in organic semiconducting films is critical to the efficiency of natural and artificial light harvesting. While these materials exhibit a high degree of structural heterogeneity on the nanoscale, traditional measurements of exciton migration lengths are performed on bulk samples. Since both the characteristic length scales of structural heterogeneity and the reported bulk diffusion lengths are smaller than the optical diffraction limit, we adapt far-field super-resolution fluorescence imaging to uncover the correlations between the structural and energetic landscapes that the excitons explore. By combining the ultrafast super-resolved measurements with exciton hopping simulations we furthermore specify the nature (in addition to the extent) of exciton migration as a function of the intrinsic and ensemble chromophore energy scales that determine a spatio-energetic landscape for migration. In collaboration with: Samuel Penwell, Lucas Ginsberg, University of California, Berkeley and Rodrigo Noriega University of Utah.

  17. Graphite and carbonaceous materials in a molten salt nuclear reactor

    International Nuclear Information System (INIS)

    Rousseau, Ginette; Lecocq, Alfred; Hery, Michel.

    1982-09-01

    A project for a molten salt 1000 MWe reactor is studied by EDF-CEA teams. The design provides for a chromesco 3 vessel housing graphite structures in which the salt circulates. The salt (Th, U, Be and Li fluorides) is cooled by direct contact with lead. The graphites and carbonated materials, inert with respect to lead and the fuel salt, are being considered not only as moderators, but as reflectors and in the construction of the sections where the heat exchange takes place. On the basis of the problems raised in the operation of the reactor, a study programme on French experimental materials (Le Carbone Lorraine, SERS, SEP) has been defined. Hence, depending on the function or functions that the material is to ensure in the structure, the criteria of choice which follow will have to be examined: behaviour under irradiation, insertion of a fluid in the material, thermal properties required, mechanical properties required, utilization [fr

  18. Bile salt receptor complex activates a pathogenic type III secretion system

    Science.gov (United States)

    Li, Peng; Rivera-Cancel, Giomar; Kinch, Lisa N; Salomon, Dor; Tomchick, Diana R; Grishin, Nick V; Orth, Kim

    2016-01-01

    Bile is an important component of the human gastrointestinal tract with an essential role in food absorption and antimicrobial activities. Enteric bacterial pathogens have developed strategies to sense bile as an environmental cue to regulate virulence genes during infection. We discovered that Vibrio parahaemolyticus VtrC, along with VtrA and VtrB, are required for activating the virulence type III secretion system 2 in response to bile salts. The VtrA/VtrC complex activates VtrB in the presence of bile salts. The crystal structure of the periplasmic domains of the VtrA/VtrC heterodimer reveals a β-barrel with a hydrophobic inner chamber. A co-crystal structure of VtrA/VtrC with bile salt, along with biophysical and mutational analysis, demonstrates that the hydrophobic chamber binds bile salts and activates the virulence network. As part of a family of conserved signaling receptors, VtrA/VtrC provides structural and functional insights into the evolutionarily conserved mechanism used by bacteria to sense their environment. DOI: http://dx.doi.org/10.7554/eLife.15718.001 PMID:27377244

  19. Bile salt receptor complex activates a pathogenic type III secretion system

    Energy Technology Data Exchange (ETDEWEB)

    Li, Peng; Rivera-Cancel, Giomar; Kinch, Lisa N.; Salomon, Dor; Tomchick, Diana R.; Grishin, Nick V.; Orth, Kim

    2016-07-05

    Bile is an important component of the human gastrointestinal tract with an essential role in food absorption and antimicrobial activities. Enteric bacterial pathogens have developed strategies to sense bile as an environmental cue to regulate virulence genes during infection. We discovered thatVibrio parahaemolyticusVtrC, along with VtrA and VtrB, are required for activating the virulence type III secretion system 2 in response to bile salts. The VtrA/VtrC complex activates VtrB in the presence of bile salts. The crystal structure of the periplasmic domains of the VtrA/VtrC heterodimer reveals a β-barrel with a hydrophobic inner chamber. A co-crystal structure of VtrA/VtrC with bile salt, along with biophysical and mutational analysis, demonstrates that the hydrophobic chamber binds bile salts and activates the virulence network. As part of a family of conserved signaling receptors, VtrA/VtrC provides structural and functional insights into the evolutionarily conserved mechanism used by bacteria to sense their environment.

  20. Effects of Hofmeister salt series on gluten network formation: Part I. Cation series.

    Science.gov (United States)

    Tuhumury, H C D; Small, D M; Day, L

    2016-12-01

    Different cationic salts were used to investigate the effects of the Hofmeister salt series on gluten network formation. The effects of cationic salts on wheat flour dough mixing properties, the rheological and the chemical properties of the gluten extracted from the dough with different respective salts, were investigated. The specific influence of different cationic salts on the gluten structure formation during dough mixing, compared to the sodium ion, were determined. The effects of different cations on dough and gluten of different flours mostly followed the Hofmeister series (NH4(+), K(+), Na(+), Mg(2+) and Ca(2+)). The impacts of cations on gluten structure and dough rheology at levels tested were relatively small. Therefore, the replacement of sodium from a technological standpoint is possible, particularly by monovalent cations such as NH4(+), or K(+). However the levels of replacement need to take into account sensory attributes of the cationic salts. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Molten salt fueled reactors with a fast salt draining

    International Nuclear Information System (INIS)

    Ventre, Edmond; Blum, J.M.

    1976-01-01

    This invention relates to a molten salt nuclear reactor which comprises a new arrangement for shutting it down in complete safety. This nuclear reactor has a molten salt primary circuit comprising, in particular, the core of this reactor. It includes a leak tight vessel the capacity of which is appreciably greater than that of the molten salt volume of the circuit and placed so that the level of the molten salt, when all the molten salt of the circuit is contained in this vessel, is less than that of the base of the core. There are facilities for establishing and maintaining an inert gas pressure in the vessel above the molten salt, for releasing the compressed gas and for connecting the vessel to the primary circuit entering this vessel at a lower level than that of the molten salt and enabling molten salt to enter or leave the vessel according to the pressure of the inert gas. The particular advantage of this reactor is that it can be shut down safely since the draining of the primary circuit no longer results from a 'positive action' but from the suppression of an arrangement essential for the operation of the reactor consisting of the build-up of the said inert gas pressure in the said vessel [fr

  2. Counterion influence on chemical shifts in strychnine salts

    Energy Technology Data Exchange (ETDEWEB)

    Metaxas, Athena E.; Cort, John R.

    2013-05-01

    The highly toxic plant alkaloid strychnine is often isolated in the form of the anion salt of its protonated tertiary amine. Here we characterize the relative influence of different counterions on 1H and 13C chemical shifts in several strychnine salts in D2O, methanol-d4 (CD3OD) and chloroform-d (CDCl3) solvents. In organic solvents, but not in water, substantial variation in chemical shifts of protons near the tertiary amine was observed among different salts. These secondary shifts reveal differences in the way each anion influences electronic structure within the protonated amine. The distributions of secondary shifts allow salts to be easily distinguished from each other as well as from the free base form. The observed effects are much greater in organic solvents than in water. Slight concentration-dependence in chemical shifts of some protons near the amine was observed for two salts in CDCl3, but this effect is small compared to the influence of the counterion. Distinct chemical shifts in different salt forms of the same compound may be useful as chemical forensic signatures for source attribution and sample matching of alkaloids such as strychnine and possibly other organic acid and base salts.

  3. Molten salt oxidation of organic hazardous waste with high salt content.

    Science.gov (United States)

    Lin, Chengqian; Chi, Yong; Jin, Yuqi; Jiang, Xuguang; Buekens, Alfons; Zhang, Qi; Chen, Jian

    2018-02-01

    Organic hazardous waste often contains some salt, owing to the widespread use of alkali salts during industrial manufacturing processes. These salts cause complications during the treatment of this type of waste. Molten salt oxidation is a flameless, robust thermal process, with inherent capability of destroying the organic constituents of wastes, while retaining the inorganic ingredients in the molten salt. In the present study, molten salt oxidation is employed for treating a typical organic hazardous waste with a high content of alkali salts. The hazardous waste derives from the production of thiotriazinone. Molten salt oxidation experiments have been conducted using a lab-scale molten salt oxidation reactor, and the emissions of CO, NO, SO 2 , HCl and dioxins are studied. Impacts are investigated from the composition of the molten salts, the types of feeding tube, the temperature of molten carbonates and the air factor. Results show that the waste can be oxidised effectively in a molten salt bath. Temperature of molten carbonates plays the most important role. With the temperature rising from 600 °C to 750 °C, the oxidation efficiency increases from 91.1% to 98.3%. Compared with the temperature, air factor has but a minor effect, as well as the composition of the molten salts and the type of feeding tube. The molten carbonates retain chlorine with an efficiency higher than 99.9% and the emissions of dioxins are below 8 pg TEQ g -1 sample. The present study shows that molten salt oxidation is a promising alternative for the disposal of organic hazardous wastes containing a high salt content.

  4. Application of Electron Structure Calculations to the Migration of Oxygen through a Perovskite Membrane

    Science.gov (United States)

    Wood, Douglas A.

    The focus of this thesis is the application of electron structure calculations, particularly density functional theory, to the analysis of the process by which oxygen is able to migrate through a perovskite crystal. This property creates the possibility of using perovskite membranes to separate oxygen from air. This could be applied to the generation of syngas directly from natural gas without the need for a separate air separation unit. A perovskite has the nominal formula ABO3 where A is a rare earth type cation and B is a transition type cation. The structure consists of the B cations arranged in a cube with the A cation in the center. The oxygen ions are located at the midpoint of each B-B cube edge and form an octahedron centered on each B cation. Any real perovskite crystal will contain a certain fraction of vacancies at the oxygen sites. Oxygen migrates through the crystal by jumping from a neighboring site to the vacancy. The permeability of the crystal is thus a function of the concentration of vacancies and the activation energy of the jump from a neighboring site to the vacancy. These properties can be modified by adding dopants for the A and B cations. The literature contains a substantial amount of experimental work on the effect of such dopants. The overall migration process can be divided into components (i) the concentration of oxygen vacancies, (ii) the activation energy for a neighboring on-site oxygen atom to jump to the vacant site, (iii) the concentration of surface vacancies, and (iv) the processes by which oxygen ions transfer back and forth between the perovskite surface and the contiguous vapor space. Using SrTiO3 and LaCoO3 as model compounds, DFT calculations have been used to (i) calculate various properties of the perovskite crystal, (ii) estimate the activation energy of a jump between an occupied oxygen site and an adjacent vacant oxygen site, (iii) predict the effects of various dopants at the A and B site and (iv) analyze the

  5. Candidate molten salt investigation for an accelerator driven subcritical core

    International Nuclear Information System (INIS)

    Sooby, E.; Baty, A.; Beneš, O.; McIntyre, P.; Pogue, N.; Salanne, M.; Sattarov, A.

    2013-01-01

    Highlights: • Developing accelerator driven subcritical fission to destroy transuranics in SNF. • The core is a vessel containing a molten mixture of NaCl and transuranic chlorides. • Molecular dynamics used to calculate the thermophysical properties of the salt. • Density and molecular structure for actinide salts reported here. • The neutronics of ADS fission in molten salt are presented. -- Abstract: We report a design for accelerator-driven subcritical fission in a molten salt core (ADSMS) that utilizes a fuel salt composed of NaCl and transuranic (TRU) chlorides. The ADSMS core is designed for fast neutronics (28% of neutrons >1 MeV) to optimize TRU destruction. The choice of a NaCl-based salt offers benefits for corrosion, operating temperature, and actinide solubility as compared with LiF-based fuel salts. A molecular dynamics (MD) code has been used to estimate properties of the molten salt system which are important for ADSMS design but have never been measured experimentally. Results from the MD studies are reported. Experimental measurements of fuel salt properties and studies of corrosion and radiation damage on candidate metals for the core vessel are anticipated

  6. Candidate molten salt investigation for an accelerator driven subcritical core

    Energy Technology Data Exchange (ETDEWEB)

    Sooby, E., E-mail: soobyes@tamu.edu [Texas A and M University, Accelerator Research Laboratory, 3380 University Dr. East, College Station, TX 77845 (United States); Baty, A. [Texas A and M University, Accelerator Research Laboratory, 3380 University Dr. East, College Station, TX 77845 (United States); Beneš, O. [European Commission, DG Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, 76125 Karlsruhe (Germany); McIntyre, P.; Pogue, N. [Texas A and M University, Accelerator Research Laboratory, 3380 University Dr. East, College Station, TX 77845 (United States); Salanne, M. [Université Pierre et Marie Curie, CNRS, Laboratoire PECSA, F-75005 Paris (France); Sattarov, A. [Texas A and M University, Accelerator Research Laboratory, 3380 University Dr. East, College Station, TX 77845 (United States)

    2013-09-15

    Highlights: • Developing accelerator driven subcritical fission to destroy transuranics in SNF. • The core is a vessel containing a molten mixture of NaCl and transuranic chlorides. • Molecular dynamics used to calculate the thermophysical properties of the salt. • Density and molecular structure for actinide salts reported here. • The neutronics of ADS fission in molten salt are presented. -- Abstract: We report a design for accelerator-driven subcritical fission in a molten salt core (ADSMS) that utilizes a fuel salt composed of NaCl and transuranic (TRU) chlorides. The ADSMS core is designed for fast neutronics (28% of neutrons >1 MeV) to optimize TRU destruction. The choice of a NaCl-based salt offers benefits for corrosion, operating temperature, and actinide solubility as compared with LiF-based fuel salts. A molecular dynamics (MD) code has been used to estimate properties of the molten salt system which are important for ADSMS design but have never been measured experimentally. Results from the MD studies are reported. Experimental measurements of fuel salt properties and studies of corrosion and radiation damage on candidate metals for the core vessel are anticipated.

  7. Permanent Disposal of Nuclear Waste in Salt

    Science.gov (United States)

    Hansen, F. D.

    2016-12-01

    Salt formations hold promise for eternal removal of nuclear waste from our biosphere. Germany and the United States have ample salt formations for this purpose, ranging from flat-bedded formations to geologically mature dome structures. Both nations are revisiting nuclear waste disposal options, accompanied by extensive collaboration on applied salt repository research, design, and operation. Salt formations provide isolation while geotechnical barriers reestablish impermeability after waste is placed in the geology. Between excavation and closure, physical, mechanical, thermal, chemical, and hydrological processes ensue. Salt response over a range of stress and temperature has been characterized for decades. Research practices employ refined test techniques and controls, which improve parameter assessment for features of the constitutive models. Extraordinary computational capabilities require exacting understanding of laboratory measurements and objective interpretation of modeling results. A repository for heat-generative nuclear waste provides an engineering challenge beyond common experience. Long-term evolution of the underground setting is precluded from direct observation or measurement. Therefore, analogues and modeling predictions are necessary to establish enduring safety functions. A strong case for granular salt reconsolidation and a focused research agenda support salt repository concepts that include safety-by-design. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. Author: F. D. Hansen, Sandia National Laboratories

  8. Effects of brine migration on waste storage systems. Final report

    International Nuclear Information System (INIS)

    Gaffney, E.S.; Nickell, R.E.

    1979-01-01

    Processes which can lead to mobilization of brine adjacent to spent fuel or nuclear waste canisters and some of the thermomechanical consequences have been investigated. Velocities as high as 4 x 10 -7 m s -1 (13 m y -1 ) are calculated at the salt/canister boundary. As much as 40 liters of pure NaCl brine could accumulate around each canister during a 10-year storage period. Accumulations of bittern brines would probably be less, in the range of 2 to 5 liters. With 0.5% water, NaCl brine accumulation over a 10-year storage cycle around a spent fuel canister producing 0.6 kW of heat is expected to be less than 1 liter for centimeter-size inclusions and less than 0.5 liter for millimeter-size inclusions. For bittern brines, about 25 years would be required to accumulate 0.4 liter. The most serious mechanical consequence of brine migration would be the increased mobility of the waste canister due to pressure solution. In pressure solution enhanced deformation, the existence of a thin film of fluid either between grains or between media (such as between a canister and the salt) provides a pathway by which the salt can be redistributed leading to a marked increase in strain rates in wet rock relative to dry rock. In salt, intergranular water will probably form discontinuous layers rather than films so that they would dominate pressure solution. A mathematical model of pressure solution indicates that pressure solution will not lead to appreciable canister motions except possibly in fine grained rocks (less than 10 -4 m). In fine grained salts, details of the contact surface between the canister and the salt bed may lead to large pressure solution motions. A numerical model indicates that heat transfer in the brine layer surrounding a spent fuel canister is not conduction dominated but has a significant convective component

  9. Migration and the Problem of Old Age People in Nepal

    Directory of Open Access Journals (Sweden)

    Tika Ram Gautam

    2008-10-01

    Full Text Available Current trends of migration in Nepal imply that the extensive out-migration of young people from rural areas, to foreign and internal urban centres, coincides with a rise in the problem of older couples in rural areas. This article examines the impact of migration on living condition and internal feelings of old age couples by drawing on the results of sociological and demographic field studies in Kandebash Village Development Committee (VDC comprising multiethnic communities of western Nepal. The methodology for identifying older people is, social survey followed by direct interview with semi-structured questionnaire, examining variations by socio-economic strata and family structures. Comparative analysis indicates considerable heterogeneity in past and present migration patterns, both within and between countries. Economically higher status families are commonly able to reinforce their position by making better use of emigration opportunities. These families are migrating permanently to urban centers within country. Migrants from economically middle and lower status families are continuing temporary migration to foreign countries. Temporary migration, both within and between countries, is making old age couples alone in rural villages. The migrants' financial and material contributions are a nominal support. The old age lonely couples are facing many problems such as feeling loneliness, helplessness, frustration, increased household and social burdening.Key words: Migration, emigration, immigration, old age couple, rural migration, NepalDOI = 10.3126/dsaj.v2i0.1361Dhaulagiri Journal of Sociology and Anthropology Vol.2 pp.145-160

  10. Structure of human milk bile salt activated lipase

    International Nuclear Information System (INIS)

    Baba, T.; Downs, D.; Jackson, K.W.; Tang, J.; Wang, Chi-Sun

    1991-01-01

    The structure and some functional sites of human milk bile salt activated lipase (BAL) were studied by cDNA cloning and chemical analysis of the enzyme. Eighteen cDNA clones of human BAL were identified from lactating human breast cDNA libraries in λgt11 and λgt10 with antibody and synthetic oligonucleotides as probes. The sequence of four clones was sufficient to construct a 3018-bp BAL cDNA structure. This sequence codes for an open reading frame of 742 amino acid residues. There is a putative signal sequence of 20 residues which is followed by the amino-terminal sequence of BAL, and the mature BAL contains 722 amino acid residues. The cDNA sequence also contains a 678-base 5'-untranslated sequence, a 97-base 3'-untranslated region, and a 14-base poly(A) tail. The sequence of a 1.8-kbp insert of clone G10-4A differs from that of the other cDNA in that it contains a deletion of 198 bases (1966-2163) corresponding to 66 amino acid residues. By use of BAL cDAN as probe, it was found that the major molecular species of BAL mRNA in human mammary gland HBL-100 cells had a size of 2.9 kb and two minor species had sizes of 3.8 and 5.1 kb by Northern blot analyses. These chemical studies established that the active site of human milk BAL is located at serine-194, the N-glycosylation site is present at asparagine-187, the O-glycosylation region is in the 16 repeating units near the C-terminus, and the heparin binding domain is in the N-terminal region. The authors have also determined the location of disulfide bridges as Cys64-Cys80 and Cys246-Cys257. The cyanogen bromide cleavage and the partial sequencing of CNBr peptides also confirmed the location of methionines in the polypeptide chain as well as the deduced cDNA sequence of BAL

  11. Automated sensitivity analysis of the radionuclide migration code UCB-NE-10.2

    International Nuclear Information System (INIS)

    Pin, F.G.; Worley, B.A.; Oblow, E.M.; Wright, R.Q.; Harper, W.V.

    1985-01-01

    The Salt Repository Project (SRP) of the U.S. Department of Energy is performing ongoing performance assessment analyses for the eventual licensing of an underground high-level nuclear waste repository in salt. As part of these studies, sensitivity and uncertainty analyses play a major role in the identification of important parameters, and in the identification of specific data needs for site characterization. Oak Ridge National Laboratory has supported the SRP in this effort resulting in thee development of an automated procedure for performing large scale sensitivity analysis using computer calculus. GRESS, GRadient Enhanced Software System, is a pre-compiler that can process FORTRAN computer codes and add derivative taking capabilities to the normal calculated results. The GRESS code is described and applied to the code UCB-NE-10.2 which simulates the migration through a sorption medium of the radionuclide members of a decay chain

  12. Study of constraints in using household NaCl salt for retrospective dosimetry

    Science.gov (United States)

    Elashmawy, M.

    2018-05-01

    Thermoluminescence (TL) characteristics of 5 different household NaCl salts and one analytical salt were determined to investigate the possible factors that affect the reliability of using household salt for retrospective dosimetry. Salts' TL sensitivities were found to be particle-size dependent and approached saturation at the largest size, whereas for salts that have the same particle size, the TL sensitivity depended on their origin. TL dependence on the particle size interprets significant variations in TL response reported in the literature for the same salt patch. The first TL readout indicated that all salts have similar glow curves with one distinctive peak. Typical second TL readout at two different doses showed a dramatic decrease in TL sensitivity associated with a significant change in the glow curve structure possessing two prominent peaks. Glow curve deconvolution (GCD) of the first TL readout for all salts yielded 6 individual glow peaks of first-order kinetics, whereas in GCD of second TL readouts, 5 individual glow peaks of second-order kinetics were obtained. Similarities in the glow curve structures of the first and second TL readouts suggest that additives such as KIO3 and MgCO3 have no effect on the TL process. Fading effect was evaluated for the salt of highest TL sensitivity, and it was found that the integral TL intensity decreased gradually and lost 40% of its initial value over 2 weeks, after which it remained constant. Results conclude that a household salt cannot be used for retrospective dosimetry without considering certain constraints such as the salt's origin and particle size. Furthermore, preparedness for radiological accidents and accurate dose reconstructions require that most of the commonly distributed household salt brands should be calibrated in advance and stored in a repository to be recalled in case of accidents.

  13. Challenging issues in the study of fiscally-induced migration.

    Science.gov (United States)

    Winer, S L

    1986-01-01

    This paper reviews Shaw's book, INTERMETROPOLITAN MIGRATION IN CANADA, which provides new evidence concerning the link between fiscal structure and internal migration. Shaw bases his work on a valuable new migration series he has put together from census data: intermetropolitan flows from 1956-1981. The existence of censua data at 5-year intervals permits Shaw enough data to estimate migration equations separately for the periods before and after 1971. A comparison of the role of fiscal variables before and after 1971 is interesting because unemployment insurance, equalization payments, and provincial natural resource revenues probably became more important in determining regional differences in incomes after 1971 than in the 20 years prior to that. Shaw suspects that migration behavior has become less sensitive to traditional market variables such as wage differentials and more sensitive to other factors, including quality of life indicators since 1950. The author thinks that Shaw's conclusion cannot rest comfortably on estimating equations that omit fiscal variables. The overall role of wage differentials in determining observed migration patterns is the product of the coefficient on wage variables and the actual evolution of wages over the estimation period. Another problem with the methodology used to contrast pre- and post-1971 migration equations is the apparent neglect of statistical testing for shifts in coefficients on the traditional economic variables and for shifts in the coefficients on the fiscal variables. The strongest of the useful results from the study concern the role of unemployment insurance. The evidence that these have an influence on internal migration is now compelling. Shaw's book adds substantial weight to the view that variation in fiscal structure plays a significant role in determining internal migration patterns.

  14. SSR-based association mapping of salt tolerance in cotton (Gossypium hirsutum L.).

    Science.gov (United States)

    Zhao, Y L; Wang, H M; Shao, B X; Chen, W; Guo, Z J; Gong, H Y; Sang, X H; Wang, J J; Ye, W W

    2016-05-25

    The identification of simple sequence repeat (SSR) markers associated with salt tolerance in cotton contributes to molecular assisted selection (MAS), which can improve the efficiency of traditional breeding. In this study, 134 samples of upland cotton cultivars were selected. The seedling emergence rates were tested under 0.3% NaCl stress. A total of 74 SSR markers were used to scan the genomes of these samples. To identify SSR markers associated with salt tolerance, an association analysis was performed between salt tolerance and SSR markers using TASSEL 2.1, based on the analysis of genetic structure using Structure 2.3.4. The results showed that the seedling emergence rates of 134 cultivars were significantly different, and 27 salt-sensitive and 10 salt-tolerant cultivars were identified. A total of 148 loci were found in 74 SSR markers involving 246 allelic variations, which ranged from 2 to 7 with an average of 3.32 per SSR marker. The gene diversity ranged from 0.0295 to 0.4959, with the average being 0.2897. The polymorphic information content ranged from0.0290 to 0.3729, with the average being 0.2381. This natural population was classified into two subgroups by Structure 2.3.4, containing 89 and 45 samples, respectively. Finally, eight SSR sites associated with salt tolerance ware found through an association analysis, with the rate of explanation ranging from 2.91 to 7.82% and an average of 4.32%. These results provide reference data for the use MAS for salt tolerance in cotton.

  15. Mediterranean salt giants beyond the evaporite model: The Sicily perspective

    Science.gov (United States)

    Carmelo Manuella, Fabio; Scribano, Vittorio; Carbone, Serafina; Hovland, Martin; Johnsen, Hans-Konrad; Rueslåtten, Håkon

    2017-04-01

    Mediterranean salt giants, occurring both in sub-seafloor and in onshore settings (the "Gessoso Solfifera Group"), are traditionally explained by repeated cycles of desiccation and replenishment of the entire basin. However, such hypotheses are strongly biased by mass balance calculations and geodynamic considerations. In addition, any hypothesis without full desiccation, still based on the evaporite model, should consider that seawater brines start to precipitate halite when 2/3 of the seawater has evaporated, and hence the level of the basin cannot be the same as the adjacent ocean. On the other hand, hydrothermal venting of hot saline brines onto the seafloor can precipitate salt in a deep marine basin if a layer of heavy brine exists along the seafloor. This process, likely related to sub-surface boiling or supercritical out-salting (Hovland et al., 2006), is consistent with geological evidence in the Red Sea "Deeps" (Hovland et al., 2015). Although supercritical out-salting and phase separation can sufficiently explain the formation of several marine salt deposits, even in deep marine settings, the Mediterranean salt giant formations can also be explained by the serpentinization model (Scribano et al., 2016). Serpentinization of abyssal peridotites does not involve seawater salts, and large quantities of saline brines accumulate in pores and fractures of the sub-seafloor serpentinites. If these rocks undergo thermal dehydration, for example, due to igneous intrusions, brines and salt slurries can migrate upwards as hydrothermal plumes, eventually venting at the seafloor, giving rise to giant salt deposits over time. These hydrothermal processes can take place in a temporal sequence, as it occurred in the "Caltanissetta Basin" (Sicily). There, salt accumulation associated with serpentinization started during Triassic times (and even earlier), and venting of heavy brines onto the seafloor eventually occurred in the Messinian via the hydrothermal plume mechanism

  16. Integrated geophysical study of the Triassic salt bodies' geometry and evolution in central Tunisia

    Science.gov (United States)

    Azaiez, Hajer; Amri, Dorra Tanfous; Gabtni, Hakim; Bedir, Mourad; Soussi, Mohamed

    2008-01-01

    A comprehensive study, integrating gravity, magnetic and seismic reflection data, has been used to resolve the complex Triassic salt body geometry and evolution in central Tunisia. Regional seismic lines across the study area show a detachment level in the Upper Triassic evaporites, associated with chaotic seismic facies below the Souinia, Majoura, and Mezzouna structures. The Jurassic and Lower Cretaceous seismic horizons display pinching-outs and onlapping around these structures. A stack-velocity section confirms the existence of a high-velocity body beneath the Souinia Mountain. Regional gravity and magnetic profiles in this area were elaborated from ETAP (the Tunisian Firm of Petroleum Activities) measure stations. These profiles were plotted following the same layout from the west (Souinia) to the east (Mezzouna), across the Majoura and Kharrouba mountains. They highlight associated gravity and magnetic negative anomalies. These gravity and magnetic data coupled to the reflection seismic data demonstrate that, in the Souinia, Majoura, and El Hafey zones, the Triassic salt reaches a salt pillow and a salt-dome stage, without piercing the cover. These stages are expressed by moderately low gravity anomalies. On the other hand, in the Mezzouna area (part of the North-South Axis), the Triassic salt had pierced its cover during the Upper Cretaceous and the Tertiary, reaching a more advanced stage as a salt diapir and salt wall. These stages express important low gravity and magnetic anomalies. These results confirm the model of Tanfous et al. (2005) of halokinetic movements by fault intrusions inducing, from the west to the east, structures at different stages of salt pillow, salt dome, and salt diapir.

  17. Sparse least-squares reverse time migration using seislets

    KAUST Repository

    Dutta, Gaurav

    2015-08-19

    We propose sparse least-squares reverse time migration (LSRTM) using seislets as a basis for the reflectivity distribution. This basis is used along with a dip-constrained preconditioner that emphasizes image updates only along prominent dips during the iterations. These dips can be estimated from the standard migration image or from the gradient using plane-wave destruction filters or structural tensors. Numerical tests on synthetic datasets demonstrate the benefits of this method for mitigation of aliasing artifacts and crosstalk noise in multisource least-squares migration.

  18. Salt-induced aggregation of stiff polyelectrolytes

    International Nuclear Information System (INIS)

    Fazli, Hossein; Mohammadinejad, Sarah; Golestanian, Ramin

    2009-01-01

    Molecular dynamics simulation techniques are used to study the process of aggregation of highly charged stiff polyelectrolytes due to the presence of multivalent salt. The dominant kinetic mode of aggregation is found to be the case of one end of one polyelectrolyte meeting others at right angles, and the kinetic pathway to bundle formation is found to be similar to that of flocculation dynamics of colloids as described by Smoluchowski. The aggregation process is found to favor the formation of finite bundles of 10-11 filaments at long times. Comparing the distribution of the cluster sizes with the Smoluchowski formula suggests that the energy barrier for the aggregation process is negligible. Also, the formation of long-lived metastable structures with similarities to the raft-like structures of actin filaments is observed within a range of salt concentration.

  19. Entropy measures of collective cell migration

    Science.gov (United States)

    Whitby, Ariadne; Parrinello, Simona; Faisal, Aldo

    2015-03-01

    Collective cell migration is a critical process during tissue formation and repair. To this end there is a need to develop tools to quantitatively measure the dynamics of collective cell migration obtained from microscopy data. Drawing on statistical physics we use entropy of velocity fields derived from dense optic flow to quantitatively measure collective migration. Using peripheral nerve repair after injury as experimental system, we study how Schwann cells, guided by fibroblasts, migrate in cord-like structures across the cut, paving a highway for neurons. This process of emergence of organised behaviour is key for successful repair, yet the emergence of leader cells and transition from a random to ordered state is not understood. We find fibroblasts induce correlated directionality in migrating Schwann cells as measured by a decrease in the entropy of motion vector. We show our method is robust with respect to image resolution in time and space, giving a principled assessment of how various molecular mechanisms affect macroscopic features of collective cell migration. Finally, the generality of our method allows us to process both simulated cell movement and microscopic data, enabling principled fitting and comparison of in silico to in vitro. ICCS, Imperial College London & MRC Clinical Sciences Centre.

  20. Properties of organic salt superconductors

    International Nuclear Information System (INIS)

    Whangbo, M.H.; Jung, D.; Evain, M.; Williams, J.M.; Beno, M.A.; Schultz, A.J.

    1989-01-01

    Structural and electronic properties of the β- and κ-phase superconducting salts of organic donor molecules are compared. Importance of donor... donor and donor...anion interactions involving the C-H bonds in setting the lattice softness, the electron-phonon coupling constant, and the superconducting transitions temperature are discussed

  1. Nonequimolar Mixture of Organic Acids and Bases: An Exception to the Rule of Thumb for Salt or Cocrystal.

    Science.gov (United States)

    Pratik, Saied Md; Datta, Ayan

    2016-08-04

    Formation of salt and/or cocrystal from organic acid-base mixtures has significant consequences in the pharmaceutical industry and its related intellectual property rights (IPR). On the basis of calculations using periodic dispersion corrected DFT (DFT-D2) on formic acid-pyridine adduct, we have demonstrated that an equimolar stoichiometric ratio (1:1) exists as a neutral cocrystal. On the other hand, the nonequimolar stoichiometry (4:1) readily forms an ionic salt. While the former result is in agreement with the ΔpKa rule between the base and the acid, the latter is not. Calculations reveal that, within the equimolar manifold (n:n; n = 1-4), the mixture exists as a hydrogen bonded complex in a cocrystal-like environment. However, the nonequimolar mixture in a ratio of 5:1 and above readily forms salt-like structures. Because of the cooperative nature of hydrogen bonding, the strength of the O-H···N hydrogen bond increases and eventually transforms into O(-)···H-N(+) (complete proton transfer) as the ratio of formic acid increases and forms salt as experimentally observed. Clearly, an enhanced polarization of formic acid on aggregation increases its acidity and, hence, facilitates its transfer to pyridine. Motion of the proton from formic acid to pyridine is shown to follow a relay mechanism wherein the proton that is far away from pyridine is ionized and is subsequently transferred to pyridine via hopping across the neutral formic acid molecules (Grotthuss type pathway). The dynamic nature of protons in the condensed phase is also evident for cocrystals as the barrier of intramolecular proton migration in formic acid (leading to tautomerism), ΔH(⧧)tautomer = 17.1 kcal/mol in the presence of pyridine is half of that in free formic acid (cf. ΔH(⧧)tautomer = 34.2 kcal/mol). We show that an acid-base reaction can be altered in the solid state to selectively form a cocrystal or salt depending on the strength and nature of aggregation.

  2. A basic study on fluoride-based molten salt electrolysis technology

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Il Soon [Seoul National University, Seoul (Korea); Kim, Kwang Bum [Yonsei University, Seoul (Korea); Park, Byung Gi [Seoul National University, Seoul (Korea)

    2001-04-01

    The objective of this project is to study on the physicochemical properties of fluoride molten salt, to develop numerical model for simulation of molten salt electrolysis, and to establish experimental technique of fluoride molten salt. Physicochemical data of fluoride molten salt are investigated and summarized. The numerical model, designated as REFIN is developed with diffusion-layer theory and electrochemical reaction kinetics. REFIN is benchmarked with published experimental data. REFIN has a capability to simulate multicomponent electrochemical system at transient conditions. Experimental device is developed to measure electrochemical properties of structural material for fluoride molten salt. Ni electrode is measured with cyclic voltammogram in the conditions of 600 .deg. C LiF-BeF{sub 2} and 700 .deg. C LiF-BeF{sub 2}. 74 refs., 23 figs., 57 tabs. (Author)

  3. Charge ordered insulating phases of DODHT salts with octahedral anions and a new radical salt, {beta}''-(DODHT){sub 2}TaF{sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Nishikawa, H; Oshio, H; Yasuzuka, S [Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571 (Japan); Higa, M; Kondo, R; Kagoshima, S [Department of Basic Science, University of Tokyo, Tokyo 153-8902 (Japan); Nakao, A; Sawa, H [Photon Factory, Institute of Material Structure Science, High Energy Accelerator Research Organization, Tsukuba, Ibaraki 305-0801 (Japan); Murata, K [Graduate School of Science, Osaka City University, Osaka 558-8585 (Japan)], E-mail: nishikaw@chem.tsukuba.ac.jp

    2008-10-15

    Physical properties of isostructural {beta}''-(DODHT){sub 2}X [DODHT = (l,4-dioxane-2,3-diyldithio)dihydrotetrathiafulvalene; X = PF{sub 6}, AsF{sub 6}, and SbF{sub 6}] at ambient pressure have been compared. The insulating phase of {beta}''-(DODHT){sub 2}PF{sub 6} salt has already been revealed to be a charge ordering (CO) state by X-ray diffraction study and magnetic behavior. CO in this salt was also confirmed by the observation of satellite reflections in oscillation photograph using synchrotron radiation. Transport property of {beta}''-(DODHT){sub 2}SbF{sub 6} salt was reinvestigated up to the pressure of 3.7 GPa applied by a cubic anvil apparatus. Although the SbF{sub 6} salt turned to be metallic above 2.0 GPa, no superconductivity was observed. In order to examine the anion size dependence of DODHT salts with octahedral anions, we prepared a new DODHT salt, {beta}''-(DODHT){sub 2}TaF{sub 6}, which has the larger counter anion compared with the previous salts. Crystal structure of this salt was isostructural to the other DODHT salts. The electrical and magnetic properties of this salt were similar to those of {beta}''-(DODHT){sub 2}SbF{sub 6} salt.

  4. Impact of environmental factors on the migration of Pu, Am, Np and Tc in geological systems

    International Nuclear Information System (INIS)

    Prins, M.; Pennders, R.M.J.; Frissel, M.J.

    1986-01-01

    The aim of this study is to provide geochemical data to be included in a model under construction to describe the migration of radionuclides through the geosphere. A large series of distribution coefficients was determined by batch and column experiments. The radionuclides were: Americium-241, Plutonium-238, 239 and 240, Neptunium-237 and Technetium-99. Geological materials were glauconite containing sand and materials from near Gorleben (Federal Republic of Germany). THe main variables of which the impact was studied were: pH, redox potential (Eh), salt concentration and contact time. Also the influence of textural composition, CEC, organic matter content and ionic composition of the associated ground waters on the sorption of the radionuclides was studied. From the data of the batch, column and microcosm studies it can be concluded that the migration of Pu, Am, Np and Tc will be strongly delayed due to adsorption of these nuclides on geological material. In anaerobic systems at low pH values Pu and Am will migrate faster than Np. For aerobic conditions, but also for anaerobic conditions at high pH, Np will migrate faster than Pu and Am. Tc may migrate in aerobic systems; it will become less mobile if reduction occurs. As far as modelling is concerned, without a rather detailed knowledge of the local redox potential and pH, a fair estimate of the migration is not possible

  5. Composition of fluid inclusions in Permian salt beds, Palo Duro Basin, Texas, U.S.A.

    Science.gov (United States)

    Roedder, E.; d'Angelo, W. M.; Dorrzapf, A.F.; Aruscavage, P. J.

    1987-01-01

    Several methods have been developed and used to extract and chemically analyze the two major types of fluid inclusions in bedded salt from the Palo Duro Basin, Texas. Data on the ratio K: Ca: Mg were obtained on a few of the clouds of tiny inclusions in "chevron" salt, representing the brines from which the salt originally crystallized. Much more complete quantitative data (Na, K, Ca, Mg, Sr, Cl, SO4 and Br) were obtained on ??? 120 individual "large" (mostly ???500 ??m on an edge, i.e., ??? ??? 1.6 ?? 10-4 g) inclusions in recrystallized salt. These latter fluids have a wide range of compositions, even in a given piece of core, indicating that fluids of grossly different composition were present in these salt beds during the several (?) stages of recrystallization. The analytical results indicating very large inter-and intra-sample chemical variation verify the conclusion reached earlier, from petrography and microthermometry, that the inclusion fluids in salt and their solutes are generally polygenetic. The diversity in composition stems from the combination of a variety of sources for the fluids (Permian sea, meteoric, and groundwater, as well as later migrating ground-, formation, or meteoric waters of unknown age), and a variety of subsequent geochemical processes of dissolution, precipitation and rock-water interaction. The compositional data are frequently ambiguous but do provide constraints and may eventually yield a coherent history of the events that produced these beds. Such an understanding of the past history of the evaporite sequence of the Palo Duro Basin should help in predicting the future role of the fluids in the salt if a nuclear waste repository is sited there. ?? 1987.

  6. Migration: The Present State, Problems and Perspectives of Research Paradigms

    Directory of Open Access Journals (Sweden)

    Silva Mežnarić

    2003-12-01

    Full Text Available Two prevailing paradigms in contemporary international migration research – migration as unpredictable explosion and migration as mainly predictable long cycles movement – are put into question. Both paradigms are not valid in explaining latest development in international migration field. They are too robust for reality which is satiated with novel developments in the field of volume, directions, labour markets and structure of migration flows, both voluntary and involuntary. Individual independent migrant as decision maker is coming to the fore. Therefore the reassessment of theoretical and conceptual apparatus of migration is imminent. As to the methods, mathematically supported sociological models of contemporary migration could be needed. On the basis of “new intuition”, the principles of simplicity, parsimony, and universality could lead to a theoretical innovation.

  7. Durability performance of submerged concrete structures - phase 2 : [summary].

    Science.gov (United States)

    2015-10-01

    Thousands of Florida bridges have steel-reinforced concrete piling foundations standing : in salt water. Over time, chloride ions in the water can migrate through the concrete to : attack the steel inside. The Florida Department of Transportation (FD...

  8. Mesoscale Simulations of Pore Migration in a Nuclear Fuel

    International Nuclear Information System (INIS)

    Radhakrishnan, Balasubramaniam; Gorti, Sarma B.

    2010-01-01

    The evolution of pore and grain structure in a nuclear fuel environment is strongly influenced by the local temperature, and the temperature gradient. The evolution of pore and grain structure in an externally imposed temperature gradient is simulated for a hypothetical material using a Potts model approach that allows for porosity migration by mechanisms similar to surface, grain boundary and volume diffusion, as well as the interaction of migrating pores with stationary grain boundaries. First, the migration of a single pore in a single crystal in the presence of the temperature gradient is simulated. Next, the interaction of a pore moving in a temperature gradient with a grain boundary that is perpendicular to the pore migration direction is simulated in order to capture the force exerted by the pore on the grain boundary. The simulations reproduce the expected variation of pore velocity with pore size as well as the variation of the grain boundary force with pore size.

  9. LIFE Materails: Molten-Salt Fuels Volume 8

    Energy Technology Data Exchange (ETDEWEB)

    Moir, R; Brown, N; Caro, A; Farmer, J; Halsey, W; Kaufman, L; Kramer, K; Latkowski, J; Powers, J; Shaw, H; Turchi, P

    2008-12-11

    The goals of the Laser Inertial Fusion Fission Energy (LIFE) is to use fusion neutrons to fission materials with no enrichment and minimum processing and have greatly reduced wastes that are not of interest to making weapons. Fusion yields expected to be achieved in NIF a few times per day are called for with a high reliable shot rate of about 15 per second. We have found that the version of LIFE using TRISO fuel discussed in other volumes of this series can be modified by replacing the molten-flibe-cooled TRISO fuel zone with a molten salt in which the same actinides present in the TRISO particles are dissolved in the molten salt. Molten salts have the advantage that they are not subject to radiation damage, and hence overcome the radiation damage effects that may limit the lifetime of solid fuels such as TRISO-containing pebbles. This molten salt is pumped through the LIFE blanket, out to a heat exchanger and back into the blanket. To mitigate corrosion, steel structures in contact with the molten salt would be plated with tungsten or nickel. The salt will be processed during operation to remove certain fission products (volatile and noble and semi-noble fission products), impurities and corrosion products. In this way neutron absorbers (fission products) are removed and neutronics performance of the molten salt is somewhat better than that of the TRISO fuel case owing to the reduced parasitic absorption. In addition, the production of Pu and rare-earth elements (REE) causes these elements to build up in the salt, and leads to a requirement for a process to remove the REE during operation to insure that the solubility of a mixed (Pu,REE)F3 solid solution is not exceeded anywhere in the molten salt system. Removal of the REE will further enhance the neutronics performance. With molten salt fuels, the plant would need to be safeguarded because materials of interest for weapons are produced and could potentially be removed.

  10. LIFE Materails: Molten-Salt Fuels Volume 8

    International Nuclear Information System (INIS)

    Moir, R.; Brown, N.; Caro, A.; Farmer, J.; Halsey, W.; Kaufman, L.; Kramer, K.; Latkowski, J.; Powers, J.; Shaw, H.; Turchi, P.

    2008-01-01

    The goals of the Laser Inertial Fusion Fission Energy (LIFE) is to use fusion neutrons to fission materials with no enrichment and minimum processing and have greatly reduced wastes that are not of interest to making weapons. Fusion yields expected to be achieved in NIF a few times per day are called for with a high reliable shot rate of about 15 per second. We have found that the version of LIFE using TRISO fuel discussed in other volumes of this series can be modified by replacing the molten-flibe-cooled TRISO fuel zone with a molten salt in which the same actinides present in the TRISO particles are dissolved in the molten salt. Molten salts have the advantage that they are not subject to radiation damage, and hence overcome the radiation damage effects that may limit the lifetime of solid fuels such as TRISO-containing pebbles. This molten salt is pumped through the LIFE blanket, out to a heat exchanger and back into the blanket. To mitigate corrosion, steel structures in contact with the molten salt would be plated with tungsten or nickel. The salt will be processed during operation to remove certain fission products (volatile and noble and semi-noble fission products), impurities and corrosion products. In this way neutron absorbers (fission products) are removed and neutronics performance of the molten salt is somewhat better than that of the TRISO fuel case owing to the reduced parasitic absorption. In addition, the production of Pu and rare-earth elements (REE) causes these elements to build up in the salt, and leads to a requirement for a process to remove the REE during operation to insure that the solubility of a mixed (Pu,REE)F3 solid solution is not exceeded anywhere in the molten salt system. Removal of the REE will further enhance the neutronics performance. With molten salt fuels, the plant would need to be safeguarded because materials of interest for weapons are produced and could potentially be removed.

  11. Return Migration among Elderly, Chronically Ill Bosnian Refugees

    DEFF Research Database (Denmark)

    Handlos, Line Neerup; Olwig, Karen Fog; Bygbjerg, Ib Christian

    2015-01-01

    Elderly migrants constitute a considerable share of global return migration; nevertheless, literature on the health aspects of the return migration among these migrants is still scarce. This study explores the significance of return migration among elderly, chronically ill Bosnian refugees from...... Denmark and the role of health issues in their decision to return. It is based on semi-structured interviews with 33 elderly, chronically ill Bosnian refugees who have moved back to Bosnia and Herzegovina, and 10 elderly, chronically ill Bosnian refugees who have remained in Denmark. The interviews show...

  12. Salt brickwork as long-term sealing in salt formations

    International Nuclear Information System (INIS)

    Walter, F.; Yaramanci, U.

    1993-01-01

    Radioactive wastes can be disposed of in deep salt formations. Rock salt is a suitable geologic medium because of its unique characteristics. Open boreholes, shafts and drifts are created to provide physical access to the repository. Long-term seals must be emplaced in these potential pathways to prevent radioactive release into the biosphere. The sealing materials must be mechanically and, most important, geochemically stable within the host rock. Salt bricks made from compressed salt-powder are understood to be the first choice long-term sealing material. Seals built of salt bricks will be ductile. Large sealing systems are built by combining the individual bricks with mortar. Raw materials for mortar are fine-grained halite powder and ground saliferous clay. This provides for the good adhesive strength of the mortar to the bricks and the high shear-strength of the mortar itself. To test the interaction of rock salt with an emplaced long-term seal, experiments will be carried out in situ, in the Asse salt mine in Germany. Simple borehole sealing experiments will be performed in horizontal holes and a complicated drift sealing experiment is planned, to demonstrate the technology of sealing a standard size drift or shaft inside a disturbed rock mass. Especially, the mechanical stability of the sealing system has to be demonstrated

  13. Intimate Partner Violence and Forced Migration during Pregnancy: Structural Constraints to Women’s Agency

    Science.gov (United States)

    Turan, Janet M.; Hatcher, Abigail M.; Romito, Patrizia; Mangone, Emily; Durojaiye, Modupeoluwa; Odero, Merab; Camlin, Carol S.

    2015-01-01

    Little is known about migration during pregnancy related to intimate partner violence (IPV). In this paper, we examine issues of agency in relation to pregnant women’s migrations in a high HIV prevalence area of Kenya. We qualitatively explored forced migration among pregnant women, using data from in-depth interviews, focus groups, and IPV screening forms. To quantitatively examine migration during pregnancy, we analyzed data from a prospective study of 614 pregnant women. The qualitative data revealed that women had varied responses to violence in pregnancy, with some being able to leave the marital home voluntarily as a strategy to escape violence. Others were ‘sent packing’ from their marital homes when they dared to exercise autonomy, in some cases related to HIV status. Quantitative analyses revealed that pregnant women who migrated were more educated, less likely to be living with a partner, and had fewer children than other women. Migration among pregnant women in Kenya illustrates the complexity of understanding women’s agency in the context of IPV. The findings indicate that there is not a dichotomy between “victim” and “agent”, but rather a complex dynamic between and within pregnant women, who may sequentially or simultaneously experience aspects of victimhood and/or agentic response. PMID:25996287

  14. Migration from a terrestrial network to a satellite network - Risks/constraints/payoffs

    Science.gov (United States)

    Homon, K. A.

    The migration method is regarded as a straightforward approach to a customer's requirements while addressing the known constraints. The migration plan organizes, controls, and communicates the extensive number of tasks, schedules, technical details, and node-by-node conversion details using the selected migration method as its cornerstone. It is noted that a successful migration plan must also provide the flexibility and robustness necessary to handle the unforeseen changes that will occur over the three- to four-year migration period. A baseline network provides a solid structural underpinning for the migration plan.

  15. Backfill barriers for nuclear waste repositories in salt

    Energy Technology Data Exchange (ETDEWEB)

    Nowak, E J; Odoj, R; Merz, E [eds.

    1981-06-01

    Backfill materials were evaluated for containment of radionuclides, chemical modification of brine, and sensitivity to hydrothermal conditions. Experimental conditions were relevant to nuclear waste isolation in bedded salt. They were based on geologic conditions at the site of the Waste Isolation Pilot Plant (WIPP) in southeastern New Mexico, USA. Conclusions are: backfill mixtures surrounding the waste form and canister can provide a neutral or slightly acidic, potentially reducing environment, prevent convective aqueous flow, and act as an effective radionuclide migration barrier; bentonite is likely to remain hydrothermally stable but potentially sensitive to waste package interactions which could alter the pH, the ratio of dissolved ions, or the sorption properties of radionuclide species; effects of irradiation from high level waste should be investigated.

  16. Forecasting the space-time stability of radioactive waste isolation in salt formations

    International Nuclear Information System (INIS)

    Anderson, E.B.; Karelin, A.I.; Krivokhatsiy, A.S.; Savonenkov, V.G.

    1992-01-01

    The possibilities to use salt formations for radioactive waste isolation are realized by creating shaft-type underground repositories in these rocks in Germany and the USA. The burial safety of low- and intermediate-level wastes for several hundred years have been substantiated for the sites chosen. Specialists of different countries presented positive properties of rock salt as a medium for isolation of radionuclides. A rich experience in building subsurface structures for different purposes in salts is accumulated in our country. Detailed investigations of salt formation have shown that far from all the saliferous areas and structures may be used for constructing burial sites. One of the reasons for this limitation is a sharp difference of individual deposits by their compositions, structures, the character of deposition and the conditions of formation. The geological criteria of safety acquire special significance in connection with the necessity to isolate radionuclides having the half-loves more than 1000 years. The time intervals required for stable isolation make up millions of years and cover great cycles of the evolution of the Earth surface and biosphere

  17. Structural differences between the avian and human H7N9 hemagglutinin proteins are attributable to modifications in salt bridge formation: a computational study with implications in viral evolution.

    Science.gov (United States)

    Cueno, Marni E; Imai, Kenichi; Tamura, Muneaki; Ochiai, Kuniyasu

    2013-01-01

    Influenza A hemagglutinin (HA) is a homotrimeric glycoprotein composed of a fibrous globular stem supporting a globular head containing three sialic acid binding sites responsible for infection. The H7N9 strain has consistently infected an avian host, however, the novel 2013 strain is now capable of infecting a human host which would imply that the HA in both strains structurally differ. A better understanding of the structural differences between the avian and human H7N9 strains may shed light into viral evolution and transmissibility. In this study, we elucidated the structural differences between the avian and human H7N9 strains. Throughout the study, we generated HA homology models, verified the quality of each model, superimposed HA homology models to determine structural differences, and, likewise, elucidated the probable cause for these structural differences. We detected two different types of structural differences between the novel H7N9 human and representative avian strains, wherein, one type (Pattern-1) showed three non-overlapping regions while the other type (Pattern-2) showed only one non-overlapping region. In addition, we found that superimposed HA homology models exhibiting Pattern-1 contain three non-overlapping regions designated as: Region-1 (S1571-A1601); Region-3 (R2621-S2651); and Region-4 (S2701-D2811), whereas, superimposed HA homology models showing Pattern-2 only contain one non-overlapping region designated as Region-2 (S1371-S1451). We attributed the two patterns we observed to either the presence of salt bridges involving the E1141 residue or absence of the R1411:D771 salt bridge. Interestingly, comparison between the human H7N7 and H7N9 HA homology models showed high structural similarity. We propose that the putative absence of the R1411:D771 salt bridge coupled with the putative presence of the E1141:R2621 and E1141:K2641 salt bridges found in the 2013 H7N9 HA homology model is associated to human-type receptor binding. This

  18. Structural differences between the avian and human H7N9 hemagglutinin proteins are attributable to modifications in salt bridge formation: a computational study with implications in viral evolution.

    Directory of Open Access Journals (Sweden)

    Marni E Cueno

    Full Text Available Influenza A hemagglutinin (HA is a homotrimeric glycoprotein composed of a fibrous globular stem supporting a globular head containing three sialic acid binding sites responsible for infection. The H7N9 strain has consistently infected an avian host, however, the novel 2013 strain is now capable of infecting a human host which would imply that the HA in both strains structurally differ. A better understanding of the structural differences between the avian and human H7N9 strains may shed light into viral evolution and transmissibility. In this study, we elucidated the structural differences between the avian and human H7N9 strains. Throughout the study, we generated HA homology models, verified the quality of each model, superimposed HA homology models to determine structural differences, and, likewise, elucidated the probable cause for these structural differences. We detected two different types of structural differences between the novel H7N9 human and representative avian strains, wherein, one type (Pattern-1 showed three non-overlapping regions while the other type (Pattern-2 showed only one non-overlapping region. In addition, we found that superimposed HA homology models exhibiting Pattern-1 contain three non-overlapping regions designated as: Region-1 (S1571-A1601; Region-3 (R2621-S2651; and Region-4 (S2701-D2811, whereas, superimposed HA homology models showing Pattern-2 only contain one non-overlapping region designated as Region-2 (S1371-S1451. We attributed the two patterns we observed to either the presence of salt bridges involving the E1141 residue or absence of the R1411:D771 salt bridge. Interestingly, comparison between the human H7N7 and H7N9 HA homology models showed high structural similarity. We propose that the putative absence of the R1411:D771 salt bridge coupled with the putative presence of the E1141:R2621 and E1141:K2641 salt bridges found in the 2013 H7N9 HA homology model is associated to human-type receptor binding

  19. Move alone or together: The roles of household structure and characteristics in migration in Indonesia

    NARCIS (Netherlands)

    Pardede, Elda

    2016-01-01

    The role of family in migration decision-making is presumed to be more pronounced in developing countries. By perceiving migration of one or more household members as a result of family strategy, some under-explored issues on migration in Indonesia are assessed in this study, namely: to what extent

  20. 3D cancer cell migration in a confined matrix

    Science.gov (United States)

    Alobaidi, Amani; Sun, Bo

    Cancer cell migration is widely studied in 2D motion, which does not mimic the invasion processes in vivo. More recently, 3D cell migration studies have been performed. The ability of cancer cells to migrate within the extracellular matrix depends on the physical and biochemical features of the extracellular matrix. We present a model of cell motility in confined matrix geometry. The aim of the study is to study cancer migration in collagen matrix, as a soft tissue, to investigate their motility within the confined and surrounding collagen environment. Different collagen concentrations have been used to show the ability of these cancer cells to move through such a complex structure by measuring Cancer cell migration velocity as well as the displacement. Graduate student physics department.

  1. Salt Induced Decay of Masonry and Electrokinetic Repair

    DEFF Research Database (Denmark)

    Ottosen, Lisbeth M.; Rörig-Dalgaard, Inge

    in brick depending on its water content and salts may be precipitated on the outer wall or concentrated under paint layers covering the surface of the brick. Different types of damage may appear in masonry walls due to these concentrating phenomena. Bricks themselves can be destroyed and the mortar can...... of bricks without increased salt content is very low compared to soils in general. Furthermore in a masonry wall there are boundaries with different chemistry (e.g. pH) that the ions must pass, brick-mortar boundaries. From initial experiments with electrokinetic removal of Ca2+ ions from bricks good......Salt induced decay of bricks is caused when salts exert internal pressures, which exceed the strength of the stone. The presence of aqueous electrolyte solutions in the capillary pores of brick materials can under changing climate conditions cause deterioration of wall structures. Ions move...

  2. The structure and behavior of salts in kraft recovery boilers

    Energy Technology Data Exchange (ETDEWEB)

    Backman, R.; Badoi, R.D.; Enestam, S. [Aabo Akademi Univ., Turku (Finland). Combustion Chemistry Research Group

    1997-10-01

    The melting behavior in the salt system (Na,K)(CO{sub 3},SO{sub 4},S,Cl,OH) is investigated by laboratory methods to enhance and further develop a chemical model for salt mixtures with compositions relevant for recovery boilers. The model, based on both literature data and experimental work can be used as (a) submodel in models for the over-all chemistry in recovery boilers and to estimate (b) deposit formation on heat transfer surfaces (fouling), (c) the melting properties of the fly ash, and (d) the smelt bed in recovery boilers. Experimental techniques used are thermal analysis, high temperature microscopy` and scanning electron microscopy. The model is implemented in a global calculation model which can handle both gas phases and condensed phases in the recovery boiler. The model gives a detailed description of the chemical reactions involved in the fume and dust formation in different locations of the flue gas channel in the boiler. (orig.)

  3. Viscosities of oxalic acid and its salts in water and binary aqueous ...

    Indian Academy of Sciences (India)

    Unknown

    Viscosities; oxalic acid and its salts; water + THF mixtures; structure-breakers. 1. Introduction ... has found its application in the organic syntheses as manifested from ... water. In other words, these results indicate that oxalic acid and its salts mix ...

  4. Rethinking the role of edaphic condition in halophyte vegetation degradation on salt marshes due to coastal defense structure

    Science.gov (United States)

    Xie, Tian; Cui, Baoshan; Bai, Junhong; Li, Shanze; Zhang, Shuyan

    2018-02-01

    Determining how human disturbance affects plant community persistence and species conservation is one of the most pressing ecological challenges. The large-scale disturbance form defense structures usually have a long-term and potential effect on phytocommunity in coastal saltmarshes. Coastal defense structures usually remove the effect of tidal wave on tidal salt marshes. As a consequence, edaphic factors such as the salinity and moisture contents are disturbed by tidal action blocking. However, few previous studies have explicitly addressed the response of halophyte species persistence and dynamics to the changing edaphic conditions. The understanding of the response of species composition in seed banks and aboveground vegetation to the stress is important to identify ecological effect of coastal defense structures and provide usefully insight into restoration. Here, we conducted a field study to distinguish the density, species composition and relationships of seed bank with aboveground vegetation between tidal flat wetlands with and without coastal defense structures. We also addressed the role of edaphic condition in vegetation degradation caused by coastal defense structures in combination with field monitor and greenhouse experiments. Our results showed the density of the seed bank and aboveground vegetation in the tidal flat without coastal defense structures was significantly lower than the surrounded flat with coastal defense structures. A total of 14 species were founded in the surrounded flat seed bank and 11 species in the tidal flat, but three species were only recorded in aboveground vegetation of the tidal flat which was much lower than 24 aboveground species in the surrounded flat. The absent of species in aboveground vegetation contributed to low germination rate which depend on the edaphic condition. The germination of seeds in the seed bank were inhabited by high soil salinity in the tidal flat and low soil moisture in the surrounded flat. Our

  5. In-Situ TEM Study of Interface Sliding and Migration in an Ultrafine Lamellar Structure

    Energy Technology Data Exchange (ETDEWEB)

    Hsiung, L M

    2005-12-06

    The instability of interfaces in an ultrafine TiAl-({gamma})/Ti{sub 3}Al-({alpha}{sub 2}) lamellar structure by straining at room temperature has been investigated using in-situ straining techniques performed in a transmission electron microscope. The purpose of this study is to obtain experimental evidence to support the creep mechanisms based upon the interface sliding in association with a cooperative movement of interfacial dislocations previously proposed to interpret the nearly linear creep behavior observed from ultrafine lamellar TiAl alloys. The results have revealed that both the sliding and migration of lamellar interfaces can take place simultaneously as a result of the cooperative movement of interfacial dislocations.

  6. Corrosion resistant structural materials for use in lithium fluoride molten salts and thermonuclear device using it

    International Nuclear Information System (INIS)

    Kawamura, Kazutaka; Takagi, Ryuzo.

    1987-01-01

    Purpose: To provide blanket materials for thermo nuclear devices and structural materials for containers with less MHD effect and good heat exchanging efficiency. Constitution: LiF-PbF 2 is used as the liquid blanket material for moderating the MHD effect. That is, the lithium compound, in the form of a fluoride, can be made easily liquefiable being and PbF 2 is added for lowering the melting point. The reason of using the fluoride is that fluorine material is less activated by the adsorption of neutrons. Copper, phosphor bronze, nickel or nickel-based alloy, e.g., Monel metal is used as corrosion resistant structural material to LiF-PbF 2 molten salts. Use of copper as the low activating structural material can provide an excellent effect also in view of the maintenance and, further, a series of processes for purifying, separating injecting and recoverying tritium can be conducted safely and stationarily without contaminating the circumferences. (Kamimura, M.)

  7. Migration from relational to NoSQL database

    Science.gov (United States)

    Ghotiya, Sunita; Mandal, Juhi; Kandasamy, Saravanakumar

    2017-11-01

    Data generated by various real time applications, social networking sites and sensor devices is of very huge amount and unstructured, which makes it difficult for Relational database management systems to handle the data. Data is very precious component of any application and needs to be analysed after arranging it in some structure. Relational databases are only able to deal with structured data, so there is need of NoSQL Database management System which can deal with semi -structured data also. Relational database provides the easiest way to manage the data but as the use of NoSQL is increasing it is becoming necessary to migrate the data from Relational to NoSQL databases. Various frameworks has been proposed previously which provides mechanisms for migration of data stored at warehouses in SQL, middle layer solutions which can provide facility of data to be stored in NoSQL databases to handle data which is not structured. This paper provides a literature review of some of the recent approaches proposed by various researchers to migrate data from relational to NoSQL databases. Some researchers proposed mechanisms for the co-existence of NoSQL and Relational databases together. This paper provides a summary of mechanisms which can be used for mapping data stored in Relational databases to NoSQL databases. Various techniques for data transformation and middle layer solutions are summarised in the paper.

  8. SUBJECTIVITIES OF SURVIVAL: CONCEPTUALISING JUST RESPONSES TO DISPLACEMENT, CROSS-BORDER MIGRATION AND STRUCTURAL VIOLENCE IN SOUTH AFRICA

    Directory of Open Access Journals (Sweden)

    Holscher, Dorothee

    2016-07-01

    Full Text Available This article considers the implications for social work of displacement, migration and structural violence in urban South Africa. To this end, I explore the life stories of five cross-border migrants. I find that all five form part of South Africa’s larger pool of surplus populations but face additional, citizenship-based forms of exclusion. Even though generally self-reliant, all of them experienced cumulative agency constraints and felt vulnerable. Against this background, I propose that current, refugee-centred services should be expanded and that interventions should be carefully balanced to attend to structural issues, inter-group conflict and the range of vulnerabilities articulated by cross-border migrants.

  9. Geothermal studies of seven interior salt domes

    International Nuclear Information System (INIS)

    1983-06-01

    This report defines and compares the geothermal environments of eight selected Gulf Coast salt domes. The thermal regimes in and around Gulf Coast salt domes are not well documented. The data base used for this study is an accumulation of bottom-hole temperature readings from oil and gas exploration wells and temperature logs run for the National Waste Terminal Storage (NWTS) program. The bottom-hole tempreatures were corrected in order to estimate the actual geothermal environments. Prior thermal studies and models indicate temperatures in and around salt domes are elevated above the norm by 1 0 F to 25 0 F. Using existing geothermal data and accepted theory, geothermal gradients for the selected domes and surrounding sediments were estimated. This study concludes that salt domes within a given basin have similar geothermal gradients, but that the basins differ in average geothermal gradients. This relationship is probably controlled by deep basement structural trends. No evidence of residual heat of emplacement was found associated with any of the selected domes

  10. Preliminary study on lithium-salt aqueous solution blanket

    International Nuclear Information System (INIS)

    Yoshida, Hiroshi; Naruse, Yuji; Yamaoka, Mitsuaki; Ohara, Atsushi; Ono, Kiyoshi; Kobayashi, Shigetada.

    1992-06-01

    Aqueous solution blanket using lithium salts such as LiNO 3 and LiOH have been studied in the US-TIBER program and ITER conceptual design activity. In the JAERI/LANL collaboration program for the joint operation of TSTA (Tritium Systems Test Assembly), preliminary design work of blanket tritium system for lithium ceramic blanket, aqueous solution blanket and liquid metal blanket, have been performed to investigate technical feasibility of tritium demonstration tests using the TSTA. Detail study of the aqueous solution blanket concept have not been performed in the Japanese fusion program, so that this study was carried out to investigate features of its concept and to evaluated its technical problems. The following are the major items studied in the present work: (i) Neutronics of tritium breeding ratio and shielding performance Lithium concentration, Li-60 enrichment, beryllium or lead, composition of structural material/beryllium/solution, heavy water, different lithium-salts (ii) Physicochemical properties of salts Solubility, corrosion characteristics and compatibility with structural materials, radiolysis (iii) Estimation of radiolysis in ITER aqueous solution blanket. (author)

  11. Quantifying drag on wellbore casings in moving salt sheets

    Science.gov (United States)

    Weijermars, R.; Jackson, M. P. A.; Dooley, T. P.

    2014-08-01

    Frontier hydrocarbon development projects in the deepwater slopes of the Gulf of Mexico Basin, Santos Basin and Lower Congo Basin all require wells to cross ductile layers of autochthonous or allochthonous salt moving at peak rates of 100 mm yr-1. The Couette-Poiseuille number is introduced here to help pinpoint the depth of shear stress reversal in such salt layers. For any well-planned through salt, the probable range of creep forces of moving salt needs to be taken into account when designing safety margins and load-factor tolerance of the well casing. Drag forces increase with wellbore diameter, but more significantly with effective viscosity and speed of the creeping salt layer. The potential drag forces on cased wellbores in moving salt sheets are estimated analytically using a range of salt viscosities (1015-1019 Pa s) and creep rates (0-10 mm yr-1). Drag on perfectly rigid casing of infinite strength may reach up to 13 Giga Newton per meter wellbore length in salt having a viscosity of 1019 Pa s. Well designers may delay stress accumulations due to salt drag when flexible casing accommodates some of the early displacement and strain. However, all creeping salt could displace, fracture and disconnect well casing, eventually. The shear strength of typical heavy duty well casing (about 1000 MPa) can be reached due to drag by moving salt. Internal flow of salt will then fracture the casing near salt entry and exit points, but the structural damage is likely to remain unnoticed early in the well-life when the horizontal shift of the wellbore is still negligibly small (at less than 1 cm yr-1). Disruption of casing and production flow lines within the anticipated service lifetime of a well remains a significant risk factor within distinct zones of low-viscosity salt which may reach ultrafast creep rates of 100 mm yr-1.

  12. Void migration, coalescence and swelling in fusion materials

    International Nuclear Information System (INIS)

    Cottrell, G.A.

    2003-01-01

    A recent analysis of the migration of voids and bubbles, produced in neutron irradiated fusion materials, is outlined. The migration, brought about by thermal hopping of atoms on the surface of a void, is normally a random Brownian motion but, in a temperature gradient, can be slightly biassed up the gradient. Two effects of such migrations are the transport of voids and trapped transmutation helium atoms to grain boundaries, where embrittlement may result; and the coalescence of migrating voids, which reduces the number of non-dislocation sites available for the capture of knock-on point defects and thereby enables the dislocation bias process to maintain void swelling. A selection of candidate fusion power plant armour and structural metals have been analysed. The metals most resistant to void migration and its effects are tungsten and molybdenum. Steel and beryllium are least so and vanadium is intermediate

  13. Comparative miRomics of Salt-Tolerant and Salt-Sensitive Rice

    Directory of Open Access Journals (Sweden)

    Goswami Kavita

    2017-06-01

    Full Text Available Increase in soil salt causes osmotic and ionic stress to plants, which inhibits their growth and productivity. Rice production is also hampered by salinity and the effect of salt is most severe at the seedling and reproductive stages. Salainity tolerance is a quantitative property controlled by multiple genes coding for signaling molecules, ion transporters, metabolic enzymes and transcription regulators. MicroRNAs are key modulators of gene-expression that act at the post-transcriptional level by translation repression or transcript cleavage. They also play an important role in regulating plant’s response to salt-stress. In this work we adopted the approach of comparative and integrated data-mining to understand the miRNA-mediated regulation of salt-stress in rice. We profiled and compared the miRNA regulations using natural varieties and transgenic lines with contrasting behaviors in response to salt-stress. The information obtained from sRNAseq, RNAseq and degradome datasets was integrated to identify the salt-deregulated miRNAs, their targets and the associated metabolic pathways. The analysis revealed the modulation of many biological pathways, which are involved in salt-tolerance and play an important role in plant phenotype and physiology. The end modifications of the miRNAs were also studied in our analysis and isomiRs having a dynamic role in salt-tolerance mechanism were identified.

  14. International migration in Asia and the Pacific: trends, problems, and recommendations.

    Science.gov (United States)

    Alberto Diaz, C

    1986-01-01

    Like other parts of the world, the Asia and Pacific region has experienced mass movements of the population within and across countries. This report presents the issues and problems discussed, and the recommendations given at the Expert Group Meeting on International Migration in Asia and the Pacific, held in 1984 in Manila. The 9 issues discussed include: 1) available data on international migration are often inconsistent, incomplete, and inadequate for a thorough analysis of the migration situation; 2) the conventional economic theory of migration, and the modern view are different, but related; 3) are internal and international migration 2 distinct phenomena, or are they simply opposite ends of a continuum ranging from short-distance moves within a country to long-distance moves across national boundaries?; 4) permanent migration from Asia and the Pacific to the US, Canada, Australia, and New Zealand has risen sharply over the the past few years; 5) international migration could have considerable effects on the size, composition, growth, and structure of the populations of both sending and receiving countries; 6) temporary labor migration to the Middle East increased rapidly in the recent past; 7) temporary labor migration has benefits and costs to the home country and to the returning workers and their families; 8) refugee movements within and from Asia have had significant repercussions, not only in the lives of the migrants themselves, but also in the national policies and social structures of the asylum countries; and 9) international migration, if properly controlled and organized, could work for the benefit of every country involved.

  15. Assessment of brine migration risks along vertical pathways due to CO2 injection

    Science.gov (United States)

    Kissinger, Alexander; Class, Holger

    2015-04-01

    Global climate change, shortage of resources and the growing usage of renewable energy sources has lead to a growing demand for the utilization of subsurface systems. Among these competing uses are Carbon Capture and Storage (CCS), geothermal energy, nuclear waste disposal, 'renewable' methane or hydrogen storage as well as the ongoing production of fossil resources like oil, gas and coal. Additionally, these technologies may also create conflicts with essential public interests such as water supply. For example, the injection of CO2 into the subsurface causes an increase in pressure reaching far beyond the actual radius of influence of the CO2 plume, potentially leading to large amounts of displaced salt water. In this work we focus on the large scale impacts of CO2 storage on brine migration but the methodology and the obtained results may also apply to other fields like waste water disposal, where large amounts of fluid are injected into the subsurface. In contrast to modeling on the reservoir scale the spatial scale required for this work is much larger in both vertical and lateral direction, as the regional hydrogeology has to be considered. Structures such as fault zones, hydrogeological windows in the Rupelian clay or salt domes are considered as potential pathways for displaced fluids into shallow systems and their influence has to be taken into account. We put the focus of our investigations on the latter type of scenario, since there is still a poor understanding of the role that salt diapirs would play in CO2 storage projects. As there is hardly any field data available on this scale, we compare different levels of model complexity in order to identify the relevant processes for brine displacement and simplify the modeling process wherever possible, for example brine injection vs. CO2 injection, simplified geometries vs. the complex formation geometry and the role of salt induced density differences on flow. Further we investigate the impact of the

  16. A low-risk aqueous lithium salt blanket for engineering test reactors

    International Nuclear Information System (INIS)

    Gierszewski, P.

    1986-09-01

    A simple blanket concept is proposed based on 1-3 wt.% lithium dissolved as a salt in low temperature (80 degrees C) and low pressure (0.1 MPa) water. This concept can provide, for example, a 0.5 tritium breeding ratio with 60% steel structure and 70% coverage. The use of neutron multipliers, other structural materials (especially zirconium alloys), higher coverage and higher lithium salt concentrations allows tritium breeding ratios over unity if necessary. Other advantages of this concept include the simple shield-like geometry, substantial structural volume for mechanical strength, excellent heat transfer ability of water coolant, efficient neutron and gamma shielding through the combination of high-Z structure and low-Z water, and conventional tritium recovery and control technology. This concept could initially provide the shielding needs for an engineering test reactor and later, by the addition of lithium salt and tritium recovery systems, also provide tritium breeding. This staged operation and liquid breeder/coolant allows control over the tritium inventory in the device without machine disassembly. 14 refs

  17. Seventy years of continuous encroachment substantially increases 'blue carbon' capacity as mangroves replace intertidal salt marshes.

    Science.gov (United States)

    Kelleway, Jeffrey J; Saintilan, Neil; Macreadie, Peter I; Skilbeck, Charles G; Zawadzki, Atun; Ralph, Peter J

    2016-03-01

    Shifts in ecosystem structure have been observed over recent decades as woody plants encroach upon grasslands and wetlands globally. The migration of mangrove forests into salt marsh ecosystems is one such shift which could have important implications for global 'blue carbon' stocks. To date, attempts to quantify changes in ecosystem function are essentially constrained to climate-mediated pulses (30 years or less) of encroachment occurring at the thermal limits of mangroves. In this study, we track the continuous, lateral encroachment of mangroves into two south-eastern Australian salt marshes over a period of 70 years and quantify corresponding changes in biomass and belowground C stores. Substantial increases in biomass and belowground C stores have resulted as mangroves replaced salt marsh at both marine and estuarine sites. After 30 years, aboveground biomass was significantly higher than salt marsh, with biomass continuing to increase with mangrove age. Biomass increased at the mesohaline river site by 130 ± 18 Mg biomass km(-2)  yr(-1) (mean ± SE), a 2.5 times higher rate than the marine embayment site (52 ± 10 Mg biomass km(-2) yr(-1) ), suggesting local constraints on biomass production. At both sites, and across all vegetation categories, belowground C considerably outweighed aboveground biomass stocks, with belowground C stocks increasing at up to 230 ± 62 Mg C km(-2) yr(-1) (± SE) as mangrove forests developed. Over the past 70 years, we estimate mangrove encroachment may have already enhanced intertidal biomass by up to 283 097 Mg and belowground C stocks by over 500 000 Mg in the state of New South Wales alone. Under changing climatic conditions and rising sea levels, global blue carbon storage may be enhanced as mangrove encroachment becomes more widespread, thereby countering global warming. © 2015 John Wiley & Sons Ltd.

  18. Cooking without salt

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000760.htm Cooking without salt To use the sharing features on ... other dishes to add zest. Try Salt-free Cooking Explore cooking with salt substitutes. Add a splash ...

  19. The effect of radial migration on galactic disks

    International Nuclear Information System (INIS)

    Vera-Ciro, Carlos; D'Onghia, Elena; Navarro, Julio; Abadi, Mario

    2014-01-01

    We study the radial migration of stars driven by recurring multi-arm spiral features in an exponential disk embedded in a dark matter halo. The spiral perturbations redistribute angular momentum within the disk and lead to substantial radial displacements of individual stars, in a manner that largely preserves the circularity of their orbits and that results, after 5 Gyr (∼40 full rotations at the disk scale length), in little radial heating and no appreciable changes to the vertical or radial structure of the disk. Our results clarify a number of issues related to the spatial distribution and kinematics of migrators. In particular, we find that migrators are a heavily biased subset of stars with preferentially low vertical velocity dispersions. This 'provenance bias' for migrators is not surprising in hindsight, for stars with small vertical excursions spend more time near the disk plane, and thus respond more readily to non-axisymmetric perturbations. We also find that the vertical velocity dispersion of outward migrators always decreases, whereas the opposite holds for inward migrators. To first order, newly arrived migrators simply replace stars that have migrated off to other radii, thus inheriting the vertical bias of the latter. Extreme migrators might therefore be recognized, if present, by the unexpectedly small amplitude of their vertical excursions. Our results show that migration, understood as changes in angular momentum that preserve circularity, can strongly affect the thin disk, but cast doubts on models that envision the Galactic thick disk as a relic of radial migration.

  20. Potash in a salt mushroom at Hormoz Island, Hormoz Strait, Iran

    DEFF Research Database (Denmark)

    Talbot, Christopher; Aftabi, Pedram; Chemia, Zurab

    2009-01-01

    marine erosion removed any salt mountains from a sub-group of near-shore Zagros diapirs and exposed their deeper structural levels. Even though these diapirs are still active, their potash deposits are likely more tractable to safe exploitation than in a salt mountain — as we make clear here for Hormoz...

  1. Controlled Release Kinetics in Hydroxy Double Salts: Effect of Host Anion Structure

    Directory of Open Access Journals (Sweden)

    Stephen Majoni

    2014-01-01

    Full Text Available Nanodimensional layered metal hydroxides such as layered double hydroxides (LDHs and hydroxy double salts (HDSs can undergo anion exchange reactions releasing intercalated anions. Because of this, these metal hydroxides have found applications in controlled release delivery of bioactive species such as drugs and pesticides. In this work, isomers of hydroxycinnamate were used as model compounds to systematically explore the effects of anion structure on the rate and extent of anion release in HDSs. Following intercalation and subsequent release of the isomers, it has been demonstrated that the nature and position of substituent groups on intercalated anions have profound effects on the rate and extent of release. The extent of release was correlated with the magnitude of dipole moments while the rate of reaction showed strong dependence on the extent of hydrogen bonding within the layers. The orthoisomer showed a more sustained and complete release as compared to the other isomers.

  2. Mechanical and Thermophysical Properties of Cubic Rock-Salt AlN Under High Pressure

    Science.gov (United States)

    Lebga, Noudjoud; Daoud, Salah; Sun, Xiao-Wei; Bioud, Nadhira; Latreche, Abdelhakim

    2018-03-01

    Density functional theory, density functional perturbation theory, and the Debye model have been used to investigate the structural, elastic, sound velocity, and thermodynamic properties of AlN with cubic rock-salt structure under high pressure, yielding the equilibrium structural parameters, equation of state, and elastic constants of this interesting material. The isotropic shear modulus, Pugh ratio, and Poisson's ratio were also investigated carefully. In addition, the longitudinal, transverse, and average elastic wave velocities, phonon contribution to the thermal conductivity, and interesting thermodynamic properties were predicted and analyzed in detail. The results demonstrate that the behavior of the elastic wave velocities under increasing hydrostatic pressure explains the hardening of the corresponding phonons. Based on the elastic stability criteria under pressure, it is found that AlN with cubic rock-salt structure is mechanically stable, even at pressures up to 100 GPa. Analysis of the Pugh ratio and Poisson's ratio revealed that AlN with cubic rock-salt structure behaves in brittle manner.

  3. Synthesis, growth, structural, optical, thermal, electrical and mechanical properties of hydrogen bonded organic salt crystal: Triethylammonium-3, 5-dinitrosalicylate

    Science.gov (United States)

    Rajkumar, Madhu; Chandramohan, Angannan

    2017-04-01

    Triethylammonium-3, 5-dinitrosalicylate, an organic salt was synthesized and single crystals grown by slow solvent evaporation solution growth technique using methanol as a solvent. The presence of various functional groups and mode of vibrations has been confirmed by FT-IR spectroscopic technique. The UV-vis-NIR Spectrum was recorded in the range 200-1200 nm to find optical transmittance window and lower cut off wavelength of the title crystal. The formation of the salt and the molecular structure was confirmed by NMR spectroscopic technique. Crystal system, crystalline nature, cell parameters and hydrogen bonding interactions of the grown crystal were determined by single crystal x-ray diffraction analysis. The thermal characteristics of grown crystal were analyzed by thermo gravimetric and differential thermal analyses. Dielectric studies were carried out to study the distribution of charges within the crystal. The mechanical properties of the title crystal were studied by Vicker's microhardness technique.

  4. Salt Tolerance

    OpenAIRE

    Xiong, Liming; Zhu, Jian-Kang

    2002-01-01

    Studying salt stress is an important means to the understanding of plant ion homeostasis and osmo-balance. Salt stress research also benefits agriculture because soil salinity significantly limits plant productivity on agricultural lands. Decades of physiological and molecular studies have generated a large body of literature regarding potential salt tolerance determinants. Recent advances in applying molecular genetic analysis and genomics tools in the model plant Arabidopsis thaliana are sh...

  5. Association analysis of salt tolerance in cowpea (Vigna unguiculata (L.) Walp) at germination and seedling stages.

    Science.gov (United States)

    Ravelombola, Waltram; Shi, Ainong; Weng, Yuejin; Mou, Beiquan; Motes, Dennis; Clark, John; Chen, Pengyin; Srivastava, Vibha; Qin, Jun; Dong, Lingdi; Yang, Wei; Bhattarai, Gehendra; Sugihara, Yuichi

    2018-01-01

    This is the first report on association analysis of salt tolerance and identification of SNP markers associated with salt tolerance in cowpea. Cowpea (Vigna unguiculata (L.) Walp) is one of the most important cultivated legumes in Africa. The worldwide annual production in cowpea dry seed is 5.4 million metric tons. However, cowpea is unfavorably affected by salinity stress at germination and seedling stages, which is exacerbated by the effects of climate change. The lack of knowledge on the genetic underlying salt tolerance in cowpea limits the establishment of a breeding strategy for developing salt-tolerant cowpea cultivars. The objectives of this study were to conduct association mapping for salt tolerance at germination and seedling stages and to identify SNP markers associated with salt tolerance in cowpea. We analyzed the salt tolerance index of 116 and 155 cowpea accessions at germination and seedling stages, respectively. A total of 1049 SNPs postulated from genotyping-by-sequencing were used for association analysis. Population structure was inferred using Structure 2.3.4; K optimal was determined using Structure Harvester. TASSEL 5, GAPIT, and FarmCPU involving three models such as single marker regression, general linear model, and mixed linear model were used for the association study. Substantial variation in salt tolerance index for germination rate, plant height reduction, fresh and dry shoot biomass reduction, foliar leaf injury, and inhibition of the first trifoliate leaf was observed. The cowpea accessions were structured into two subpopulations. Three SNPs, Scaffold87490_622, Scaffold87490_630, and C35017374_128 were highly associated with salt tolerance at germination stage. Seven SNPs, Scaffold93827_270, Scaffold68489_600, Scaffold87490_633, Scaffold87490_640, Scaffold82042_3387, C35069468_1916, and Scaffold93942_1089 were found to be associated with salt tolerance at seedling stage. The SNP markers were consistent across the three models and

  6. Structural Evolution of central part of the Tuzgolu (Salt Lake) Basin, Central Anatolia, Turkey

    Science.gov (United States)

    Ada, M.; Cemen, I.; Çaptuğ, A.; Demirci, M.; Engin, C.

    2017-12-01

    The Tuzgolu Basin in Central Anatolia, Turkey, covers low-relief areas located between the Pontide Mountains to the North and Tauride Mountains to the South. The basin started to form as a rift basin during the Late Maastrichtian. The main Tuzgolu-Aksaray fault zone on the eastern margin of the basin and the northwest trending Yeniceoba and Cihanbeyli fault zones on the western margin of the basin were probably developed during that time. The basin has also experienced westward extension in response to westward escape of the Anatolian plate since Late Miocene. Several geologic studies have been conducted in the Tuz Gölü (Salt Lake) Basin and surrounding areas to determine structural and tectono-stratigraphic development of the basin. However, there are still many questions regarding the structural evolution of the basin. The main purpose of this study is to investigate the structural evolution of the central Tuzgolu Basin based on the structural interpretation of available 2-D seismic reflection profiles, well log analysis and construction of structural cross sections. The cross-sections will be based on depth converted seismic lines to determine structural geometry of the faults and folds. A preliminary Petrel project has been prepared using available seismic profiles. Our preliminary structural interpretations suggest that a well-developed rollover anticline was developed with respect to the westward extension in Central Anatolia. The rollover anticline is faulted in its crest area by both down-to-the west and down-to-the east normal faults. The geometry of the main boundary fault at depth still remains in question. We anticipate that this question will be resolved based on depth converted structural cross-sections and their restoration.

  7. Leachate migration from a solid waste disposal facility near Biscayne National Park, South Florida

    International Nuclear Information System (INIS)

    Waller, B.G.; Labowski, J.L.

    1987-01-01

    Leachate from the Dade County Solid Waste Disposal Facility (SWDF) is migrating to the east (seaward) and to the south from the currently active disposal cell. Water levels and ground-water flow directions are strongly influenced by water-management practices, especially in the Black Creek Canal and structure S-21 to the north of the SWDF. Ground-water flow is initially to the south, from Black Creek Canal, and then to the east through the disposal area. The SWDF is constructed over the salt-intruded part of the highly transmissive Biscayne aquifer and because of this, chloride ion concentrations and specific conductance levels could not be used as indicators of leachate concentrations. Water-quality indicators used to identify leachate migration were primarily ammonium, organic nitrogen, phenols, and chemical oxygen demand with cadmium, chromium, and lead used as auxiliary indicator constituents. Leachate was detected in multi-depth wells located 75 meters to the south and 20 meters to the east of the active cell. Concentrations of water-quality indicators had mean concentrations generally 2 to 10 times higher than baseline conditions. Leachate was not detected in any of the other ground-water, canal water, or Biscayne Bay sampling sites. Primary controls over leachate movement in the SWDF are water-management practices in the Black Creek and Gould Canals, configuration and integrity of the liner beneath the active cell, and low hydraulic gradients in the landfill area

  8. Interdependence of macrophage migration and ventral nerve cord development in Drosophila embryos.

    Science.gov (United States)

    Evans, Iwan R; Hu, Nan; Skaer, Helen; Wood, Will

    2010-05-01

    During embryonic development, Drosophila macrophages (haemocytes) undergo a series of stereotypical migrations to disperse throughout the embryo. One major migratory route is along the ventral nerve cord (VNC), where haemocytes are required for the correct development of this tissue. We show, for the first time, that a reciprocal relationship exists between haemocytes and the VNC and that defects in nerve cord development prevent haemocyte migration along this structure. Using live imaging, we demonstrate that the axonal guidance cue Slit and its receptor Robo are both required for haemocyte migration, but signalling is not autonomously required in haemocytes. We show that the failure of haemocyte migration along the VNC in slit mutants is not due to a lack of chemotactic signals within this structure, but rather to a failure in its detachment from the overlying epithelium, creating a physical barrier to haemocyte migration. This block of haemocyte migration in turn disrupts the formation of the dorsoventral channels within the VNC, further highlighting the importance of haemocyte migration for correct neural development. This study illustrates the important role played by the three-dimensional environment in directing cell migration in vivo and reveals an intriguing interplay between the developing nervous system and the blood cells within the fly, demonstrating that their development is both closely coupled and interdependent.

  9. Geological Feasibility of Underground Oil Storage in Jintan Salt Mine of China

    Directory of Open Access Journals (Sweden)

    Xilin Shi

    2017-01-01

    Full Text Available A number of large underground oil storage spaces will be constructed in deep salt mines in China in the coming years. According to the general geological survey, the first salt cavern oil storage base of China is planned to be built in Jintan salt mine. In this research, the geological feasibility of the salt mine for oil storage is identified in detail as follows. (1 The characteristics of regional structure, strata sediment, and impermeable layer distribution of Jintan salt mine were evaluated and analyzed. (2 The tightness of cap rock was evaluated in reviews of macroscopic geology and microscopic measuring. (3 According to the geological characteristics of Jintan salt mine, the specific targeted formation for building underground oil storage was chosen, and the sealing of nonsalt interlayers was evaluated. (4 Based on the sonar measuring results of the salt caverns, the characteristics of solution mining salt caverns were analyzed. In addition, the preferred way of underground oil storage construction was determined. (5 Finally, the results of closed well observation in solution mining salt caverns were assessed. The research results indicated that Jintan salt mine has the basic geological conditions for building large-scale underground oil storage.

  10. Structural insights into the adaptation of proliferating cell nuclear antigen (PCNA) from Haloferax volcanii to a high-salt environment

    International Nuclear Information System (INIS)

    Morgunova, Ekaterina; Gray, Fiona C.; MacNeill, Stuart A.; Ladenstein, Rudolf

    2009-01-01

    The crystal structure of PCNA from the halophilic archaeon H. volcanii reveals specific features of the charge distribution on the protein surface that reflect adaptation to a high-salt environment and suggests a different type of interaction with DNA in halophilic PCNAs. The sliding clamp proliferating cell nuclear antigen (PCNA) plays vital roles in many aspects of DNA replication and repair in eukaryotic cells and in archaea. Realising the full potential of archaea as a model for PCNA function requires a combination of biochemical and genetic approaches. In order to provide a platform for subsequent reverse genetic analysis, PCNA from the halophilic archaeon Haloferax volcanii was subjected to crystallographic analysis. The gene was cloned and expressed in Escherichia coli and the protein was purified by affinity chromatography and crystallized by the vapour-diffusion technique. The structure was determined by molecular replacement and refined at 3.5 Å resolution to a final R factor of 23.7% (R free = 25%). PCNA from H. volcanii was found to be homotrimeric and to resemble other homotrimeric PCNA clamps but with several differences that appear to be associated with adaptation of the protein to the high intracellular salt concentrations found in H. volcanii cells

  11. Sea salt

    OpenAIRE

    Galvis-Sánchez, Andrea C.; Lopes, João Almeida; Delgadillo, Ivone; Rangel, António O. S. S.

    2013-01-01

    The geographical indication (GI) status links a product with the territory and with the biodiversity involved. Besides, the specific knowledge and cultural practices of a human group that permit transforming a resource into a useful good is protected under a GI designation. Traditional sea salt is a hand-harvested product originating exclusively from salt marshes from specific geographical regions. Once salt is harvested, no washing, artificial drying or addition of anti-caking agents are all...

  12. Evaluation of the effect of salts on chemical, structural, textural, sensory and heating properties of cheese: Contribution of conventional methods and spectral ones.

    Science.gov (United States)

    Loudiyi, M; Aït-Kaddour, A

    2018-03-21

    Chemical composition, sensory characteristics, textural and functional properties are among the most important characteristics, which directly relates to the global quality of cheese and to consumer acceptability. A number of factors including milk composition, processing conditions and salt content, influences these properties. The past decades many investigations were performed on the possibilities to reduce salt content of cheese due to its adverse health effects, the current lifestyle and the awareness of the consumers for nutrition quality products. Due to the multiple potential effects of reducing NaCl (simple reduction or substitution) on cheese attributes, it is of utmost importance to identify and understand those effects in order to control the global quality and safety of the final product. In the present review a collection of the different results and conclusions drawn after studying the effect of salts by conventional (e.g. wet chemistry) and instrumental (e.g. spectral) methods on chemical, structural, textural, sensory and heating properties of cheese are presented.

  13. Submarine Salt Karst Terrains

    Directory of Open Access Journals (Sweden)

    Nico Augustin

    2016-06-01

    Full Text Available Karst terrains that develop in bodies of rock salt (taken as mainly of halite, NaCl are special not only for developing in one of the most soluble of all rocks, but also for developing in one of the weakest rocks. Salt is so weak that many surface-piercing salt diapirs extrude slow fountains of salt that that gravity spread downslope over deserts on land and over sea floors. Salt fountains in the deserts of Iran are usually so dry that they flow at only a few cm/yr but the few rain storms a decade so soak and weaken them that they surge at dm/day for a few days. We illustrate the only case where the rates at which different parts of one of the many tens of subaerial salt karst terrains in Iran flows downslope constrains the rates at which its subaerial salt karst terrains form. Normal seawater is only 10% saturated in NaCl. It should therefore be sufficiently aggressive to erode karst terrains into exposures of salt on the thousands of known submarine salt extrusions that have flowed or are still flowing over the floors of hundreds of submarine basins worldwide. However, we know of no attempt to constrain the processes that form submarine salt karst terrains on any of these of submarine salt extrusions. As on land, many potential submarine karst terrains are cloaked by clastic and pelagic sediments that are often hundreds of m thick. Nevertheless, detailed geophysical and bathymetric surveys have already mapped likely submarine salt karst terrains in at least the Gulf of Mexico, and the Red Sea. New images of these two areas are offered as clear evidence of submarine salt dissolution due to sinking or rising aggressive fluids. We suggest that repeated 3D surveys of distinctive features (± fixed seismic reflectors of such terrains could measure any downslope salt flow and thus offer an exceptional opportunity to constrain the rates at which submarine salt karst terrains develop. Such rates are of interest to all salt tectonicians and the many

  14. Analysis of structure-tectonic pattern within the 'Degelen' massif conformably to conditions of radionuclide migration in ground water

    International Nuclear Information System (INIS)

    Gorbunova, Eh.M.; Ivanchenko, G.N.; Godunova, L.D.

    2005-01-01

    Major orientation of radiation monitoring on the Semipalatinsk test site lies in direction of common regularities for formation and distribution of radioactive contamination. Zones, within the 'Degelen' technical area. of hydrogeological active faults are patly subjected to impact of underground explosions. Data of computer-aided decryption of a stellite image by means of program package LESSA allow specification of para-genesis structures standing as probabilistic pathways of radionuclide migration. (author)

  15. Vertically migrating swimmers generate aggregation-scale eddies in a stratified column.

    Science.gov (United States)

    Houghton, Isabel A; Koseff, Jeffrey R; Monismith, Stephen G; Dabiri, John O

    2018-04-01

    Biologically generated turbulence has been proposed as an important contributor to nutrient transport and ocean mixing 1-3 . However, to produce non-negligible transport and mixing, such turbulence must produce eddies at scales comparable to the length scales of stratification in the ocean. It has previously been argued that biologically generated turbulence is limited to the scale of the individual animals involved 4 , which would make turbulence created by highly abundant centimetre-scale zooplankton such as krill irrelevant to ocean mixing. Their small size notwithstanding, zooplankton form dense aggregations tens of metres in vertical extent as they undergo diurnal vertical migration over hundreds of metres 3,5,6 . This behaviour potentially introduces additional length scales-such as the scale of the aggregation-that are of relevance to animal interactions with the surrounding water column. Here we show that the collective vertical migration of centimetre-scale swimmers-as represented by the brine shrimp Artemia salina-generates aggregation-scale eddies that mix a stable density stratification, resulting in an effective turbulent diffusivity up to three orders of magnitude larger than the molecular diffusivity of salt. These observed large-scale mixing eddies are the result of flow in the wakes of the individual organisms coalescing to form a large-scale downward jet during upward swimming, even in the presence of a strong density stratification relative to typical values observed in the ocean. The results illustrate the potential for marine zooplankton to considerably alter the physical and biogeochemical structure of the water column, with potentially widespread effects owing to their high abundance in climatically important regions of the ocean 7 .

  16. Solution Behavior and Activity of a Halophilic Esterase under High Salt Concentration

    Science.gov (United States)

    Rao, Lang; Zhao, Xiubo; Pan, Fang; Li, Yin; Xue, Yanfen; Ma, Yanhe; Lu, Jian R.

    2009-01-01

    Background Halophiles are extremophiles that thrive in environments with very high concentrations of salt. Although the salt reliance and physiology of these extremophiles have been widely investigated, the molecular working mechanisms of their enzymes under salty conditions have been little explored. Methodology/Principal Findings A halophilic esterolytic enzyme LipC derived from archeaon Haloarcula marismortui was overexpressed from Escherichia coli BL21. The purified enzyme showed a range of hydrolytic activity towards the substrates of p-nitrophenyl esters with different alkyl chains (n = 2−16), with the highest activity being observed for p-nitrophenyl acetate, consistent with the basic character of an esterase. The optimal esterase activities were found to be at pH 9.5 and [NaCl] = 3.4 M or [KCl] = 3.0 M and at around 45°C. Interestingly, the hydrolysis activity showed a clear reversibility against changes in salt concentration. At the ambient temperature of 22°C, enzyme systems working under the optimal salt concentrations were very stable against time. Increase in temperature increased the activity but reduced its stability. Circular dichroism (CD), dynamic light scattering (DLS) and small angle neutron scattering (SANS) were deployed to determine the physical states of LipC in solution. As the salt concentration increased, DLS revealed substantial increase in aggregate sizes, but CD measurements revealed the maximal retention of the α-helical structure at the salt concentration matching the optimal activity. These observations were supported by SANS analysis that revealed the highest proportion of unimers and dimers around the optimal salt concentration, although the coexistent larger aggregates showed a trend of increasing size with salt concentration, consistent with the DLS data. Conclusions/Significance The solution α-helical structure and activity relation also matched the highest proportion of enzyme unimers and dimers. Given that

  17. Synthesis and structure-activity relationship of di-(3, 8-diazabicyclo[3.2.1]octane) diquaternary ammonium salts as unique analgesics.

    Science.gov (United States)

    Liu, Hong; Cheng, Tie-Ming; Zhang, Hong-Mei; Li, Run-Tao

    2003-11-01

    Based on the structure characteristics of the lead compounds, 1, 1' octanedioyl-4, 4'-dimethyl-4, 4'-dibenzyl dipiperazinium dibromide (2) and 3, 8-disubstituted-3, 8-diazabicyclo [3.2.1]octanes (DBO), di-(3, 8-diazabicyclo [3.2.1]octane) diquaternary ammonium salts 3 a-c were designed and synthesized through a highly practical procedure. Target compounds 3 a-c and the hydrochloride salts of their precursors 10 a-c were evaluated for their in vivo analgesic and sedative activities. Interestingly, the introduction of an endoethylenic bridge in the piperazine of lead compound 2 causes loss of the analgesic activity and increases the toxicity dramatically. This result shows that the flexible conformation of piperazine in compound 2 is favorable for interaction with the receptor, and the quaternization of compounds 10 a-c is the main reason for the toxicity increase.

  18. Protein thermal stability enhancement by designing salt bridges: a combined computational and experimental study.

    Directory of Open Access Journals (Sweden)

    Chi-Wen Lee

    Full Text Available Protein thermal stability is an important factor considered in medical and industrial applications. Many structural characteristics related to protein thermal stability have been elucidated, and increasing salt bridges is considered as one of the most efficient strategies to increase protein thermal stability. However, the accurate simulation of salt bridges remains difficult. In this study, a novel method for salt-bridge design was proposed based on the statistical analysis of 10,556 surface salt bridges on 6,493 X-ray protein structures. These salt bridges were first categorized based on pairing residues, secondary structure locations, and Cα-Cα distances. Pairing preferences generalized from statistical analysis were used to construct a salt-bridge pair index and utilized in a weighted electrostatic attraction model to find the effective pairings for designing salt bridges. The model was also coupled with B-factor, weighted contact number, relative solvent accessibility, and conservation prescreening to determine the residues appropriate for the thermal adaptive design of salt bridges. According to our method, eight putative salt-bridges were designed on a mesophilic β-glucosidase and 24 variants were constructed to verify the predictions. Six putative salt-bridges leaded to the increase of the enzyme thermal stability. A significant increase in melting temperature of 8.8, 4.8, 3.7, 1.3, 1.2, and 0.7°C of the putative salt-bridges N437K-D49, E96R-D28, E96K-D28, S440K-E70, T231K-D388, and Q277E-D282 was detected, respectively. Reversing the polarity of T231K-D388 to T231D-D388K resulted in a further increase in melting temperatures by 3.6°C, which may be caused by the transformation of an intra-subunit electrostatic interaction into an inter-subunit one depending on the local environment. The combination of the thermostable variants (N437K, E96R, T231D and D388K generated a melting temperature increase of 15.7°C. Thus, this study

  19. Effects of growth rate on structural property and adatom migration behaviors for growth of GaInNAs/GaAs (001) by molecular beam epitaxy

    Science.gov (United States)

    Li, Jingling; Gao, Peng; Zhang, Shuguang; Wen, Lei; Gao, Fangliang; Li, Guoqiang

    2018-03-01

    We have investigated the structural properties and the growth mode of GaInNAs films prepared at different growth rates (Rg) by molecular beam epitaxy. The crystalline structure is studied by high resolution X-ray diffraction, and the evolution of GaInNAs film surface morphologies is studied by atomic force microscopy. It is found that both the crystallinity and the surface roughness are improved by increasing Rg, and the change in the growth mode is attributed to the adatom migration behaviors particularly for In atoms, which is verified by elemental analysis. In addition, we have presented some theoretical calculation results related to the N adsorption energy to show the unique N migration behavior, which is instructive to interpret the growth mechanism of GaInNAs films.

  20. Actinide removal from molten salts by chemical oxidation and salt distillation

    Energy Technology Data Exchange (ETDEWEB)

    McNeese, J.A.; Garcia, E.; Dole, V.R. [Los Alamos National Laboratory, NM (United States)] [and others

    1995-10-01

    Actinide removal from molten salts can be accomplished by a two step process where the actinide is first oxidized to the oxide using a chemical oxidant such as calcium carbonate or sodium carbonate. After the actinide is precipitated as an oxide the molten salt is distilled away from the actinide oxides leaving a oxide powder heel and an actinide free distilled salt that can be recycled back into the processing stream. This paper discusses the chemistry of the oxidation process and the physical conditions required to accomplish a salt distillation. Possible application of an analogous process sequence for a proposed accelerator driven transmutation molten salt process is also discussed.

  1. Actinide removal from molten salts by chemical oxidation and salt distillation

    International Nuclear Information System (INIS)

    McNeese, James A.; Garcia, Eduardo; Dole, Vonda R.; Griego, Walter J.

    1995-01-01

    Actinide removal from molten salts can be accomplished by a two step process where the actinide is first oxidized to the oxide using a chemical oxidant such as calcium carbonate or sodium carbonate. After the actinide is precipitated as an oxide the molten salt is distilled away from the actinide oxides leaving a oxide powder heel and an actinide free distilled salt that can be recycled back into the processing stream. This paper discusses the chemistry of the oxidation process and the physical conditions required to accomplish a salt distillation. Possible application of an analogous process sequence for a proposed accelerator driven transmutation molten salt process is also discussed

  2. Salt consumption and the effect of salt on mineral metabolism in horses.

    Science.gov (United States)

    Schryver, H F; Parker, M T; Daniluk, P D; Pagan, K I; Williams, J; Soderholm, L V; Hintz, H F

    1987-04-01

    The voluntary salt consumption of mature unexercised horses was measured weekly for up to 45 weeks. Voluntary intake among horses was quite variable ranging from 19 to 143 g of salt per day and was inversely related to total salt intake (salt in feeds plus voluntary intake). Mean daily voluntary salt consumption was 53 g. Season of the year did not influence voluntary intake. In preference tests which evaluated every two choice combination of 0.2% and 4% NaCl in test diets fed daily for four days, ponies generally preferred diets containing the lower amount of salt. In similar preference studies which used NaHCO3 as a sodium source, ponies always preferred the diet containing the lower level of NaHCO3. Metabolism studies employing diets containing 1, 3 or 5% NaCl showed that urinary excretion was the major excretory pathway for sodium and chloride. Fecal excretion, intestinal absorption and retention of sodium were not affected by level of salt intake. Urinary calcium excretion was unaffected by salt intake but calcium and phosphorus absorption and retention were enhanced when ponies were fed diets containing 3 or 5% sodium chloride. Magnesium and copper metabolism were unaffected by salt intake. Horses voluntarily consume relatively large amounts of sodium chloride but it is likely that not all voluntary consumption is related to the salt requirement of the horse. Habit and taste preference could also be involved. Salt consumption at the levels used in these studies does not appear to be detrimental to the metabolism of other minerals in the horse.

  3. Crystal structure of (2R-1-[(methylsulfonyloxy]propan-2-aminium chloride: a chiral molecular salt

    Directory of Open Access Journals (Sweden)

    H. R. Rajegowda

    2015-10-01

    Full Text Available In the title chiral molecular salt, C4H12NO3S+·Cl−, the cation is protonated at the N atom, producing [RNH3]+, where R is CH3SO2OCH2C(HCH3. The N atom in the cation is sp3-hybridized. In the crystal, cations and anions are connected by strong N—H...Cl hydrogen bonds to generate edge-shared 12-membered rings of the form {...Cl...HNH}3. This pattern of hydrogen bonding gives rise to zigzag supramolecular layers in the ab plane. The layers are connected into a three-dimensional architecture by C—H...O hydrogen bonds. The structure was refined as an inversion twin.

  4. Automated sensitivity analysis of the radionuclide migration code UCBNE10.2

    International Nuclear Information System (INIS)

    Pin, F.G.; Worley, B.A.; Oblow, E.M.; Wright, R.Q.; Harper, W.V.

    1985-01-01

    The Salt Repository Project (SRP) of the US Department of Energy is performing ongoing performance assessment analyses for the eventual licensing of an underground high-level nuclear waste repository in salt. As part of these studies, sensitivity and uncertainty analysis play a major role in the identification of important parameters, and in the identification of specific data needs for site characterization. Oak Ridge National Laboratory has supported the SRP in this effort resulting in the development of an automated procedure for performing large-scale sensitivity analysis using computer calculus. GRESS, Gradient Enhanced Software System, is a pre-compiler that can process FORTRAN computer codes and add derivative taking capabilities to the normal calculated results. The GRESS code is described and applied to the code UCB-NE-10.2 which simulates the migration through an adsorptive medium of the radionuclide members of a decay chain. Conclusions are drawn relative to the applicability of GRESS for more general large-scale modeling sensitivity studies, and the role of such techniques in the overall SRP sensitivity/uncertainty program is detailed. 6 refs., 2 figs., 3 tabs

  5. Collective cell migration: Implications for wound healing and cancer invasion

    Directory of Open Access Journals (Sweden)

    Li Li

    2013-07-01

    Full Text Available During embryonic morphogenesis, wound repair and cancer invasion, cells often migrate collectively via tight cell-cell junctions, a process named collective migration. During such migration, cells move as coherent groups, large cell sheets, strands or tubes rather than individually. One unexpected finding regarding collective cell migration is that being a "multicellular structure" enables cells to better respond to chemical and physical cues, when compared with isolated cells. This is important because epithelial cells heal wounds via the migration of large sheets of cells with tight intercellular connections. Recent studies have gained some mechanistic insights that will benefit the clinical understanding of wound healing in general. In this review, we will briefly introduce the role of collective cell migration in wound healing, regeneration and cancer invasion and discuss its underlying mechanisms as well as implications for wound healing.

  6. Thiobarbiturate and barbiturate salts of pefloxacin drug: Growth, structure, thermal stability and IR-spectra

    Science.gov (United States)

    Golovnev, Nicolay N.; Molokeev, Maxim S.; Lesnikov, Maxim K.; Sterkhova, Irina V.; Atuchin, Victor V.

    2017-12-01

    Three new salts of pefloxacin (PefH) with thiobarbituric (H2tba) and barbituric (H2ba) acids, pefloxacinium 2-thiobarbiturate trihydrate, PefH2(Htba)·3H2O (1), pefloxacinium 2-thiobarbiturate, PefH2(Htba) (2) and bis(pefloxacinium barbiturate) hydrate, (PefH2)2(Hba)2·2.56H2O (3) are synthesized and structurally characterized by the X-ray single-crystal diffraction. The structures of 1-3 contain intramolecular hydrogen bonds Csbnd H⋯F, Osbnd H⋯O. Intermolecular hydrogen bonds Nsbnd H⋯O and Osbnd H⋯O form a 2D plane network in 1. In 2 and 3, intermolecular hydrogen bonds Nsbnd H⋯O form the infinite chains. In 1-3, the Htba- and Hba- ions are connected with PefH2+ only by one intermolecular hydrogen bond Nsbnd H⋯O. In 2 and 3, two Htba- and Hba- ions are connected by two hydrogen bonds Nsbnd H⋯O. These pairs form infinite chains. All three structures are stabilized by the π-π interactions of the head-to-tail type between PefH2+ ions. Compounds 2 and 3 are characterized by powder XRD, TG-DSC and FT-IR.

  7. Correlative STED and Atomic Force Microscopy on Live Astrocytes Reveals Plasticity of Cytoskeletal Structure and Membrane Physical Properties during Polarized Migration

    Directory of Open Access Journals (Sweden)

    Nathalie Rouach

    2017-04-01

    Full Text Available The plasticity of the cytoskeleton architecture and membrane properties is important for the establishment of cell polarity, adhesion and migration. Here, we present a method which combines stimulated emission depletion (STED super-resolution imaging and atomic force microscopy (AFM to correlate cytoskeletal structural information with membrane physical properties in live astrocytes. Using STED compatible dyes for live cell imaging of the cytoskeleton, and simultaneously mapping the cell surface topology with AFM, we obtain unprecedented detail of highly organized networks of actin and microtubules in astrocytes. Combining mechanical data from AFM with optical imaging of actin and tubulin further reveals links between cytoskeleton organization and membrane properties. Using this methodology we illustrate that scratch-induced migration induces cytoskeleton remodeling. The latter is caused by a polarization of actin and microtubule elements within astroglial cell processes, which correlates strongly with changes in cell stiffness. The method opens new avenues for the dynamic probing of the membrane structural and functional plasticity of living brain cells. It is a powerful tool for providing new insights into mechanisms of cell structural remodeling during physiological or pathological processes, such as brain development or tumorigenesis.

  8. How biophysical interactions associated with sub- and mesoscale structures and migration behavior affect planktonic larvae of the spiny lobster in the Juan Fernández Ridge: A modeling approach

    Science.gov (United States)

    Medel, Carolina; Parada, Carolina; Morales, Carmen E.; Pizarro, Oscar; Ernst, Billy; Conejero, Carlos

    2018-03-01

    The Juan Fernández Ridge (JFR) is a chain of topographical elevations in the eastern South Pacific (∼33-35°S, 76-81.5°W). Rich in endemic marine species, this ridge is frequently affected by the arrival of mesoscale eddies originating in the coastal upwelling zone off central-southern Chile. The impacts of these interactions on the structure and dynamics of the JFR pelagic system have, however, not been addressed yet. The present model-based study is focused on the coupled influence of mesoscale-submesoscale processes and biological behavior (i.e., diel vertical migration) on the horizontal distribution of planktonic larvae of the spiny lobster (Jasus frontalis) around the JFR waters. Two case studies were selected from a hydrodynamic Regional Ocean Modeling System to characterize mesoscale and submesoscale structures and an Individual-based model (IBM) to simulate diel vertical migration (DVM) and its impact on the horizontal distribution and the patchiness level. DVM behavior of these larvae has not been clearly characterized, therefore, three types of vertical mechanisms were assessed on the IBM: (1) no migration (LG), (2) a short migration (0-50 m depth, DVM1), and (3) a long migration (10-200 m depth, DVM2). The influence of physical properties (eddy kinetic energy, stretching deformation and divergence) on larval aggregation within meso and submesoscale features was quantified. The patchiness index assessed for mesoscale and submesoscale structures showed higher values in the mesoscale than in the submesoscale. However, submesoscale structures revealed a higher accumulation of particles by unit of area. Both vertical migration mechanisms produced larger patchiness indices compared to the no migration experiment. DVM2 was the one that showed by far the largest aggregation of almost all the aggregation zones. Larval concentrations were highest in the submesoscale structures; these zones were characterized by low eddy kinetic energy, negative stretching

  9. Thermal phase behaviour of N-alkyl-N-methylpyrrolidinium and piperidinium bis(trifluoromethanesulfonyl)imide salts

    International Nuclear Information System (INIS)

    Henderson, W A; Jr, V G Young; Pearson, W; Passerini, S; Long, H C De; Trulove, P C

    2006-01-01

    The phases, ion crystal packing and thermal properties of the N-alkyl-N-methylpyrrolidinium and piperidinium bis(trifluoromethanesulfonyl)imide (PYR 1R TFSI and PIP 1R TFSI (subscript R = 1 for methyl and 2 for ethyl), respectively) salts are compared using powder and single-crystal x-ray diffraction (XRD) and differential scanning calorimetry (DSC). The crystal structure of PIP 12 TFSI has been determined at 123 K. The salt crystallizes in the triclinic space group P1-bar with Z 8. Structural data are also reported for PYR 11 TFSI at 153 K and PIP 12 TFSI at 223 K. PIP 11 TFSI has identical ion crystal packing to the analogous pyrrolidinium salt PYR 11 TFSI. Since increasing the cation alkyl chain length to propyl or butyl (R = 3 or 4) reduces the melting point of the salts below room temperature, this study may provide valuable insight into why these pyrrolidinium and piperidinium salts form room-temperature ionic liquids

  10. Determination of the environmental effect for the sea salt aerosols corrosion (3)

    International Nuclear Information System (INIS)

    Nakayasu, Fumio; Umehara, Toshihiro; Kato, Akitoshi; Taniguchi, Akihide

    2009-01-01

    Fukui Prefecture presently hosts 15 reactor units, including PWRs, BWR, FBR (Monjyu) and Japanese ATR (Fugen), all of which are located along the Japan Sea. Under such a circumstange, corrosion due to sea salt aerosols is one of the major factors causing ageing degradation of nuclear power plants facilities. Many scientists have been engaged in research on the corrosion of structures due to sea salt aerosols. In pursuing sea salt aerosol-induced corrosion research, it was necessary to perform corrosion tests under a certain set of environmental conditions since corrosion of structures is highly sensitive to environmental factors. In this respect, we installed the outdoor exposure test facilities along the sea coast in Awara-city and inland in Fukui-city, Fukui Prefecture of Japan. The amounts of sea salt aerosol tend to be lower in the summer season and higher in the winter season. The difference between seasons is expected to relate to the wind speed, the sunshine time, the rain amount and others. We tried to use the multivariate analysis for finding some relations between sea salt aerosol amounts and environment factor. We found the clear relations. (author)

  11. Molten salt reactors

    International Nuclear Information System (INIS)

    Bouchter, J.C.; Dufour, P.; Guidez, J.; Simon, N.; Renault, C.

    2014-01-01

    Molten salt reactors are one of the 6 concepts retained for the 4. generation of nuclear reactors. The principle of this reactor is very innovative: the nuclear fuel is dissolved in the coolant which allows the online reprocessing of the fuel and the online recovery of the fission products. A small prototype: the Molten Salt Reactor Experiment (MSRE - 8 MWt) was operating a few years in the sixties in the USA. The passage towards a fast reactor by the suppression of the graphite moderator leads to the concept of Molten Salt Fast Reactor (MSFR) which is presently studied through different European projects such as MOST, ALISIA and EVOL. Worldwide the main topics of research are: the adequate materials resisting to the high level of corrosiveness of the molten salts, fuel salt reprocessing, the 3-side coupling between neutron transport, thermohydraulics and thermo-chemistry, the management of the changing chemical composition of the salt, the enrichment of lithium with Li 7 in the case of the use of lithium fluoride salt and the use of MSFR using U 233 fuel (thorium cycle). The last part of the article presents a preliminary safety analysis of the MSFR. (A.C.)

  12. Deposition of niobium plate on niobium-titanium from molten salts

    International Nuclear Information System (INIS)

    Matychenko, Eh.S.; Shevyrev, A.A.; Stolyarova, L.A.; Sukhorzhevskaya, S.L.

    1993-01-01

    A possibility of using Nb-Ti alloys (50 and 34 mas.% of Ti) as substrates for deposition of niobium coating of chloride-fluoride and fluoride molten salts is studied. Corrosion behaviour of alloys indicates in the electrolytic bath within 970-1070 K interval, coating structure and state of coating-substrate boundary are investigated. Chloride-fluoride molten salt usefullness for making products with niobium coatings is shown

  13. Overall and specific migration from multilayer high barrier food contact materials - kinetic study of cyclic polyester oligomers migration.

    Science.gov (United States)

    Úbeda, Sara; Aznar, Margarita; Vera, Paula; Nerín, Cristina; Henríquez, Luis; Taborda, Laura; Restrepo, Claudia

    2017-10-01

    Most multilayer high barrier materials used in food packaging have a polyurethane adhesive layer in their structures. In order to assess the safety of these materials, it is important to determine the compounds intentionally added to the adhesives (IAS) as well as those non-intentionally added substances (NIAS). During the manufacture of polyurethane adhesives, some by-products can be formed, such as cyclic polyester oligomers coming from the reaction between dicarboxylic acids and glycols. Since these compounds are not listed in the Regulation 10/2011/EU, they should not be found in migration above 0.01 mg/kg of simulant. In this study two flexible multilayer packaging materials were used and migration was evaluated in simulant A (ethanol 10% v/v), simulant B (acetic acid 3% w/v) and simulant ethanol 95% v/v during 10 days at 60ºC. Identification and quantification of non-volatile compounds was carried out by UPLC-MS-QTOF. Most of migrants were oligomers such as cyclic polyesters and caprolactam oligomers. Overall migration and specific migration of adipic acid-diethylene glycol and phthalic acid-diethylene glycol were monitored over time and analysed by UPLC-MS-TQ. In most cases, ethanol 95% v/v was the simulant with the highest concentration values. Overall migration kinetics followed a similar pattern than specific migration kinetics.

  14. A history of salt.

    Science.gov (United States)

    Cirillo, M; Capasso, G; Di Leo, V A; De Santo, N G

    1994-01-01

    The medical history of salt begins in ancient times and is closely related to different aspects of human history. Salt may be extracted from sea water, mineral deposits, surface encrustations, saline lakes and brine springs. In many inland areas, wood was used as a fuel source for evaporation of brine and this practice led to major deafforestation in central Europe. Salt played a central role in the economies of many regions, and is often reflected in place names. Salt was also used as a basis for population censuses and taxation, and salt monopolies were practised in many states. Salt was sometimes implicated in the outbreak of conflict, e.g. the French Revolution and the Indian War of Independence. Salt has also been invested with many cultural and religious meanings, from the ancient Egyptians to the Middle Ages. Man's innate appetite for salt may be related to his evolution from predominantly vegetarian anthropoids, and it is noteworthy that those people who live mainly on protein and milk or who drink salty water do not generally salt their food, whereas those who live mainly on vegetables, rice and cereals use much more salt. Medicinal use tended to emphasize the positive aspects of salt, e.g. prevention of putrefaction, reduction of tissue swelling, treatment of diarrhea. Evidence was also available to ancient peoples of its relationship to fertility, particularly in domestic animals. The history of salt thus represents a unique example for studying the impact of a widely used dietary substance on different important aspects of man's life, including medical philosophy.

  15. Normal and abnormal neuronal migration in the developing cerebral cortex.

    Science.gov (United States)

    Sun, Xue-Zhi; Takahashi, Sentaro; Cui, Chun; Zhang, Rui; Sakata-Haga, Hiromi; Sawada, Kazuhiko; Fukui, Yoshihiro

    2002-08-01

    Neuronal migration is the critical cellular process which initiates histogenesis of cerebral cortex. Migration involves a series of complex cell interactions and transformation. After completing their final mitosis, neurons migrate from the ventricular zone into the cortical plate, and then establish neuronal lamina and settle onto the outermost layer, forming an "inside-out" gradient of maturation. This process is guided by radial glial fibers, requires proper receptors, ligands, other unknown extracellular factors, and local signaling to stop neuronal migration. This process is also highly sensitive to various physical, chemical and biological agents as well as to genetic mutations. Any disturbance of the normal process may result in neuronal migration disorder. Such neuronal migration disorder is believed as major cause of both gross brain malformation and more special cerebral structural and functional abnormalities in experimental animals and in humans. An increasing number of instructive studies on experimental models and several genetic model systems of neuronal migration disorder have established the foundation of cortex formation and provided deeper insights into the genetic and molecular mechanisms underlying normal and abnormal neuronal migration.

  16. Globalization, Migration and Development

    Directory of Open Access Journals (Sweden)

    George, Susan

    2002-01-01

    Full Text Available EnglishMigration may become the most important branch of demography in the earlydecades of the new millennium in a rapidly globalizing world. This paper discusses the causes, costsand benefits of international migration to countries of the South and North, and key issues of commonconcern. International migration is as old as national boundaries, though its nature, volume,direction, causes and consequences have changed. The causes of migration are rooted in the rate ofpopulation growth and the proportion of youth in the population, their education and training,employment opportunities, income differentials in society, communication and transportationfacilities, political freedom and human rights and level of urbanization. Migration benefits the Souththrough remittances of migrants, improves the economic welfare of the population (particularly womenof South countries generally, increases investment, and leads to structural changes in the economy.However, emigration from the South has costs too, be they social or caused by factors such as braindrain. The North also benefits by migration through enhancement of economic growth, development ofnatural resources, improved employment prospects, social development and through exposure toimmigrants' new cultures and lifestyles. Migration also has costs to the North such as of immigrantintegration, a certain amount of destabilization of the economy, illegal immigration, and socialproblems of discrimination and exploitation. Issues common to both North and South include impact onprivate investment, trade, international cooperation, and sustainable development. Both North andSouth face a dilemma in seeking an appropriate balance between importing South's labour or itsproducts and exporting capital and technology from the North.FrenchLa migration est sans doute devenue la partie la plus importante de la démographie des premières décennies du nouveau millénaire dans un monde qui change rapidement. Ce

  17. The role of salt bridges on the temperature adaptation of aqualysin I, a thermostable subtilisin-like proteinase.

    Science.gov (United States)

    Jónsdóttir, Lilja B; Ellertsson, Brynjar Ö; Invernizzi, Gaetano; Magnúsdóttir, Manuela; Thorbjarnardóttir, Sigríður H; Papaleo, Elena; Kristjánsson, Magnús M

    2014-12-01

    Differences in salt bridges are believed to be a structural hallmark of homologous enzymes from differently temperature-adapted organisms. Nevertheless, the role of salt bridges on structural stability is still controversial. While it is clear that most buried salt bridges can have a functional or structural role, the same cannot be firmly stated for ion pairs that are exposed on the protein surface. Salt bridges, found in X-ray structures, may not be stably formed in solution as a result of high flexibility or high desolvation penalty. More studies are thus needed to clarify the picture on salt bridges and temperature adaptation. We contribute here to this scenario by combining atomistic simulations and experimental mutagenesis of eight mutant variants of aqualysin I, a thermophilic subtilisin-like proteinase, in which the residues involved in salt bridges and not conserved in a psychrophilic homolog were systematically mutated. We evaluated the effects of those mutations on thermal stability and on the kinetic parameters. Overall, we show here that only few key charged residues involved in salt bridges really contribute to the enzyme thermal stability. This is especially true when they are organized in networks, as here attested by the D17N mutation, which has the most remarkable effect on stability. Other mutations had smaller effects on the properties of the enzyme indicating that most of the isolated salt bridges are not a distinctive trait related to the enhanced thermal stability of the thermophilic subtilase. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Towards understanding international migration determinants today: Theoretical perspective

    Directory of Open Access Journals (Sweden)

    Predojević-Despić Jelena

    2010-01-01

    Full Text Available In times of global migration flows and ever increasing mobility of the workforce in the world, the necessity for constant deepening of theoretical knowledge is imposed as a basis for understanding main determinants of this phenomenon, and with an aim of directing the focus of migration researches towards more efficient overcoming of challenges and making use of the advantages which international migrations could bring both to origin, destination and transit countries. The main goal of this paper is to give a critical review on the development of the economic migrations theory, to state the main similarities and differences between various approaches and to point out to the main drawbacks and problems which the theoretical perspective is facing when studying the determinants of contemporary international labor migrations. The focus of the study refers to voluntary labor migrations with reference to migrations of the highly educated population, while the stress is on economic theories, although some of them are closely connected to sociological, geographical and anthropological theories. The development of the theory on international migrations has been started by micro theoretical models, namely, through the conceptualization of theories which place the individual in the focal point of research, who estimates the positive, namely negative sides of moving from one location to another. Economic models on the micro theoretical level cede more space to models of macro structure which research the social and economic structure within and between countries. There are many theoretical models which offer possible answers to the question on what are the main determinants of international migrations on the macro analytical level. Although every one of them tries to give an answer to the same question, they use different concepts, assumptions and frameworks of research. The reasons which bring about the initiation of international migrations can be

  19. Economic Integration, Opportunity Structure and Migration in Papua New Guinea

    NARCIS (Netherlands)

    D. Townsend (Don)

    1980-01-01

    textabstractThat migration is a result of perceived inequality has been positively established by comprehensive national studies (Herrick 1965; Caldwell 1969; Pryor 1975; Guarnaut 1977) and by two or three thousand village-based or local studies (Connell 1976). But whereas the mainstream of

  20. Results of and prospects for studies on molten salt nuclear reactors

    International Nuclear Information System (INIS)

    Hery, M.; Lecocq, A.

    1983-04-01

    This paper reviews the various studies performed in France by the EDF and CEA teams in the field of molten salt nuclear reactors. These studies include graphite moderating systems, feasibility of a 625 MWth core, lead cooling, structural materials, salts tritium diffusion and corrosion. The experience gained allows eventual development prospects of this system to appraised [fr