WorldWideScience

Sample records for caesium isothermal migration

  1. Type I Migration in a Non-Isothermal Protoplanetary Disk

    CERN Document Server

    Jang-Condell, H; Jang-Condell, Hannah; Sasselov, Dimitar D.

    2004-01-01

    We calculate rates of Type I migration of protoplanets in a non-isothermal three-dimensional protoplanetary disk, building upon planet-disk models developed in previous work. We find that including the vertical thickness of the disk results in a decrease in the Type I migration rate by a factor of ~2 from a two-dimensional disk. The vertical temperature variation has only a modest effect on migration rates since the torques at the midplane are weighted heavily both because the density and the perturbing potential are maximized at the midplane. However, temperature perturbations resulting from shadowing and illumination at the disk's surface can decrease the migration rate by up to another factor of 2 for planets at the gap-opening threshold at distances where viscous heating is minimal. This would help to resolve the timescale mismatch between the standard core-accretion scenario for planet formation and the survival of planets, and could help explain some of the rich diversity of planetary systems already ob...

  2. Near-isothermal conditions in the middle and lower crust induced by melt migration.

    Science.gov (United States)

    Depine, Gabriela V; Andronicos, Christopher L; Phipps-Morgan, Jason

    2008-03-01

    The thermal structure of the crust strongly influences deformation, metamorphism and plutonism. Models for the geothermal gradient in stable crust predict a steady increase of temperature with depth. This thermal structure, however, is incompatible with observations from high-temperature metamorphic terranes exhumed in orogens. Global compilations of peak conditions in high-temperature metamorphic terranes define relatively narrow ranges of peak temperatures over a wide range in pressure, for both isothermal decompression and isobaric cooling paths. Here we develop simple one-dimensional thermal models that include the effects of melt migration. These models show that long-lived plutonism results in a quasi-steady-state geotherm with a rapid temperature increase in the upper crust and nearly isothermal conditions in the middle and lower crust. The models also predict that the upward advection of heat by melt generates granulite facies metamorphism, and widespread andalusite-sillimanite metamorphism in the upper crust. Once the quasi-steady-state thermal profile is reached, the middle and lower crust are greatly weakened due to high temperatures and anatectic conditions, thus setting the stage for gravitational collapse, exhumation and isothermal decompression after the onset of plutonism. Near-isothermal conditions in the middle and lower crust result from the thermal buffering effect of dehydration melting reactions that, in part, control the shape of the geotherm. PMID:18322532

  3. Migration of a surfactant-laden droplet in non-isothermal Poiseuille flow

    CERN Document Server

    Das, Sayan; Som, S K; Chakraborty, Suman

    2016-01-01

    The motion of a surfactant-laden viscous droplet in the presence of background non-isothermal Poiseuille flow is studied analytically and numerically. Specifically, the effect of interfacial Marangoni stress due to non-uniform distribution of surfactants and temperature at the droplet interface on the velocity and direction of motion of the droplet along the centerline of imposed Poiseuille flow is investigated in the presence of linearly varying temperature field. In the absence of thermal convection, fluid inertia and shape deformation, the interfacial transport of bulk-insoluble surfactants is governed by the surface Peclet number which represents the relative strength of the advective transport of surfactant over the diffusive transport. We obtain analytical solution for small and large values of the surface Peclet number. Numerical solution is obtained for arbitrary surface Peclet number, which compares well with the analytical solution. Depending on the direction of temperature gradient with respect to ...

  4. Sorption and migration of radiocaesium in natural zeolite-water systems

    International Nuclear Information System (INIS)

    The sorption properties for caesium and its migration in a system zeolite-aqueous solution were studied for natural zoelites from Zaloshka gorica. It was found that zeolites are rather efficient sorbents for caesium even in the presence of some other electrolytes. A correlation between the rate of migration of caesium in the system zeolite-water and the sorption intensity was established. Migration of caesium from a zeolite layer by diffusion is described. (author) 7 refs.; 2 figs,; 1 tab

  5. Human metabolism of caesium

    International Nuclear Information System (INIS)

    A study of the human biokinetics of caesium in two forms, i.) incorporated in foodstuff (137Cs in perch and mushrooms) and ii.) in ionic state (134Cs in aqueous solution) has been carried out at the department of Radiation Physics in Malmoe, starting in 2001. The results of the pilot study were published in 2004, and a continuation of that study has now been carried out by means of NKS funding (NKS-B Cskinetik). The aim is to, i.) investigate whether Scandinavian populations exhibit shorter biological half-time of radiocaesium than other populations; ii.) extend the biokinetic study to additional human subjects from the other Nordic countries. Results from the continued study further indicate a near complete absorption of radiocaesium in the gastro-intestinal tract, be it in ion state or contained in food matrix. So far, the literature survey of Nordic studies on biokinetics of Cs suggests that the biological half time is somewhat shorter among Scandinavian males (84 days vs. ICRP-value of 110 days), although females do not exhibit any significant difference (64 days vs ICRP value of 65 days). (au)

  6. Leakage of caesium braquitherapy sources

    International Nuclear Information System (INIS)

    In several Venezuelan public hospitals where cervix uteri tumours are treated by intracavitary radiotherapy, that use manual after loading Fletcher method, with Caesium 137 sources, the use of improper source holders, locally manufactured from pieces of drainage plastic tubing, which deteriorated and created a corrosive environment all around the sources, omission of manufacturer's recommendations regarding corrosion information, source storage, inspection and testing, violation of International Atomic Energy Agency Radiation Protection Procedures, and lack of proper regulatory control, resulted integrity damage to about sixty special form sources (ISO2919 C 63322), leakage of Cs-137 from a supposed insoluble refractory active content (caesium silicoaluminate), and contamination of applicators, floors and bedding. When the situation was detected by means removal contamination tests, after routine inspections, the sources were removed from the hospitals, decontaminated by means of immersion in 3% EDTA solution in ultrasonic bath, subjected to leaking assessment tests, and the ones that passed were placed in low cost stainless steel source holders, designed and built by the instituto Venezolano de Investigaciones Cientificas (IVIC) returned to the hospitals. The leaking sources were removed from use and considered radioactive waste. In order to avoid the occurrence of similar situations, all the importers of such sources are now required to send them to IVIC for testing and placement in proper source holders, before they are shipped to the hospitals. (author)

  7. The spatial distribution of caesium-137 over Northern Ireland from fallout from the Chernobyl nuclear accident

    OpenAIRE

    Rawlins, B. G.; Scheib, C.; Tyler, A.N.; Jones, D.; Webster, R; Young, M. E.

    2009-01-01

    The spatial distribution of caesium-137 (137Cs) across the land is of much interest because it can tell us about the redistribution of the radionuclide as a result of soil erosion, differential migration through the soil—or its complement, differential retention in the soil. Any such inferences from survey measurements depend on the assumption of a broadly even distribution from weapons testing fallout, and the substantial deposition of 137Cs in rain following the Chernobyl accide...

  8. Transfer of atmospheric caesium to agricultural products

    International Nuclear Information System (INIS)

    A huge quantity of radioactive rubble was generated by the Great East Japan Earthquake. The Japanese government is considering incineration processing of such rubble in waste incinerators which have suitable equipment, and the government is urged to manage appropriately the radiation exposure of residents living in the vicinity of incinerators by inhalation and ingestion of food. In this study, we developed a model describing plant uptake of atmospheric caesium by direct deposition and root-absorption via soil. Analysis using our model has suggested that wet deposition contributes to transfer to a plant most, when caesium exists in the atmosphere. (author)

  9. Structure of caesium disulfate at 120 and 273 K

    DEFF Research Database (Denmark)

    Ståhl, Kenny; Berg, Rolf W.; Eriksen, Kim Michael;

    2009-01-01

    The crystal structures of Cs2S2O7 at 120 and 273 K have been determined from X-ray single-crystal data. Caesium disulfate represents a new structure type with a uniquely high number of independent formula units at 120 K: In one part caesium ions form a tube surrounding the disulfate ions, [Cs8(S2...

  10. Determination of caesium-137 in fast-reactor coolant systems.

    Science.gov (United States)

    Oldham, G; Ware, A R; Sykes, D J

    1969-03-01

    A method for the separation of caesium by ion-exchange involving ammonium 12-molybdophosphate has been investigated, and found to be 100% efficient for aqueous solutions with high sodium and potassium concentrations. PMID:18960518

  11. Sorption of caesium and strontium onto calcium silicate hydrate in saline groundwater

    International Nuclear Information System (INIS)

    Full text of publication follows: In the concept for radioactive waste disposal in Japan, cement is a potential waste packaging and backfilling material and is expected to provide chemical containment. The sorption of radionuclides onto cement materials, which controls the aqueous concentrations of elements in the pore-water, is a very important parameter when considering the release of radionuclides from the near field of a cementitious radioactive waste repository. Many safety assessment calculations currently assume radionuclide retardation as linear sorption equilibrium and describe it with a distribution ratio (Rd value). In this study, the sorption mechanism is discussed by measuring the sorption isotherm of caesium, strontium (10-5 ∼ 10-2 mol dm-3) and sodium (10-4 ∼ 10-1 mol dm-3) onto Calcium Silicate Hydrate (C-S-H gel, Ca/Si 0.65 ∼ 1.2) at a liquid:solid ratio of 100:1, to support the assumption. In addition, the competitive sorption between caesium or strontium, and sodium is studied by sorption measurements using a range of sodium chloride concentration to simulate different ionic strengths in saline groundwater. The initial and equilibrated aqueous compositions were measured in the sorption experiments and it was found that caesium, strontium and sodium were sorbed by substitution for Ca in C-S-H phases by examining the mass balance. Based on the experimental results, we propose a modelling approach in which the ion-exchange model is employed and the presence of some calcium sites with different ion-exchange log K values in C-S-H is assumed by considering the composition and the structure of C-S-H. The modelling calculation results predict the measured Rd values well and also describe the competition of sorption of caesium or strontium, and sodium in the experiments. The log K values for sorption of each cation element decreased as Ca/Si ratio of C-S-H gel increased. This agrees with the trend that C-S-H gel is negatively charged at low Ca

  12. Influence of herbivory on caesium turnover in a forest ecosystem

    International Nuclear Information System (INIS)

    The effect of herbivory by bank vole (Clethrionomys glareolus) and moose (Alces alces) in relation to litterfall in a boreal forest is analysed. The main purpose is to estimate the relative importance of these processes for the transfer of caesium-137 to soil. Biomasses of litterfall and food consumption were selected from different forest biotopes. The analysis of the input and output of caesium-137 in the vole and moose populations is based on mass balance calculations for caesium-137 in steady state conditions. From this assessment, herbivory appears to be within an order of magnitude of litterfall. With due regard to the lower caesium level in litterfall than in living plant tissue, transfer of radioactive caesium by herbivory is seen to be even higher in comparison to that by litterfall, than apparent from the corresponding transfer of organic matter. In addition, the availability of caesium-137 from animal excrements is expected to be high and fast, which further emphasises the relative importance of herbivory in feed-back from vegetation to soil

  13. Note on Two Types of Contamination of Human Beings by Caesium-137

    International Nuclear Information System (INIS)

    The authors present an elimination curve for a case of occupational contamination by caesium-137. They also show how the caesium-137 body burden varied during 1963 in a group of persons who did not undergo occupational exposure. (author)

  14. Project Caesium - An ion exchange model for the prediction of distribution coefficients of caesium in bentonite

    International Nuclear Information System (INIS)

    A surface chemical model is established to thermodynamically describe caesium sorption on bentonite. Caesium sorption is studied on Wyoming bentonite MX-80 in solutions of NaCl, KCl, MgCl2, CaCl2, NaNO3 and Ca(NO3)2 of concentrations varying between 0.025M and 1M, as well as in the weakly saline Allard groundwater and the strongly saline Aespoe groundwater. Based on these experiments it is shown that the sorption behaviour of caesium on bentonite can be described, within the experimental and model uncertainties, in terms of a one-site ion exchange model. The ion exchange constant for the replacement of Na+ on montmorillonite by Cs+ is logKex degrees = 1.6. The model predictions compare well with sorption data published in the open literature on both Wyoming bentonite MX-80 and other types of bentonite. For the analysis of diffusion experiments in compacted bentonite, the apparent diffusivity of tritiated water, HTO, is used as an analogue to estimate the pore diffusivity of Cs+. Since insufficient information is available at present to estimate the porosity actually available for diffusion in compacted bentonite, it is assumed that the diffusion porosity can be approximated by using the value of the bulk porosity. Under these circumstances, the cation ex change capacity (CEC) found to be available for the diffusing species in compacted bentonite corresponds to about 12% of the total CEC of bentonite. It is recognised that the errors made in the estimation of the pore diffusivity and of the diffusion porosity are contained in the reduction factor of the CEC. A discussion of the factors affecting the diffusivities of radionuclides and the problem of establishing consistent sets of diffusivity data is given in the Appendix. 33 refs, 7 figs, 12 tabs

  15. Available area isotherm

    NARCIS (Netherlands)

    Bosma, JC; Wesselingh, JA

    2004-01-01

    A new isotherm is presented for adsorption of proteins, the available area isotherm. This isotherm has a steric basis, unlike the (steric) mass action model. The shape of the available area isotherm is determined only by geometric exclusion. With the new isotherm, experimental results can be fitted

  16. Distribution coefficients of caesium, chlorine, iodine, niobium, selenium and technetium on Olkiluoto soils

    International Nuclear Information System (INIS)

    Retention of caesium, chlorine, iodine, niobium, selenium and technetium was investigated on soil samples from Olkiluoto using laboratory batch sorption experiments. Distribution coefficients were measured for both dried and sieved and untreated (wet, not sieved) mineral soil and humus in aerobic and anaerobic conditions. Mineralogical composition of the samples was determined by XRD-analysis. Caesium was sorbed efficiently on mineral soil samples and less efficiently on humus. Sorption decreased with decreasing cation exchange capacity and clay fraction content. The effect of competing cations decreased in the order Cs+>NH4+>K+>Ca2+>Na+. Chlorine was not retained by mineral soil samples, and the sorption was weak on humus. The sorption of iodine was the strongest on humus and the weakest on the untreated mineral soil samples in the anaerobic conditions. In the mineral soil samples, the sorption decreased with decreasing organic matter content and increasing pH. The retention of niobium on soil samples was the most efficient among the studied elements. The retention was high regardless of the aeration conditions. Sorption on humus was smaller. Selenium was retained efficiently on humus. Sorption on mineral soil samples was stronger in aerobic conditions. Sorption increased with time. Technetium was sorbed well on humus and anaerobic, untreated mineral soil samples. Sorption increased with increasing organic matter content and decreasing redox potential. The results from the sorption experiments are used in the site specific radionuclide migration modelling. (orig.)

  17. Distribution coefficients of caesium, chlorine, iodine, niobium, selenium and technetium on Olkiluoto soils

    Energy Technology Data Exchange (ETDEWEB)

    Soederlund, M.; Lusa, M.; Virtanen, S.; Vaelimaa, I.; Hakanen, M.; Lehto, J. [Univ. of Helsinki, Lab. of Radiochemistry (Finland); Lahdenperae, A.-M. [Saanio and Riekkola Oy, Helsinki (Finland)

    2014-02-15

    Retention of caesium, chlorine, iodine, niobium, selenium and technetium was investigated on soil samples from Olkiluoto using laboratory batch sorption experiments. Distribution coefficients were measured for both dried and sieved and untreated (wet, not sieved) mineral soil and humus in aerobic and anaerobic conditions. Mineralogical composition of the samples was determined by XRD-analysis. Caesium was sorbed efficiently on mineral soil samples and less efficiently on humus. Sorption decreased with decreasing cation exchange capacity and clay fraction content. The effect of competing cations decreased in the order Cs{sup +}>NH{sub 4}{sup +}>K{sup +}>Ca{sup 2+}>Na{sup +}. Chlorine was not retained by mineral soil samples, and the sorption was weak on humus. The sorption of iodine was the strongest on humus and the weakest on the untreated mineral soil samples in the anaerobic conditions. In the mineral soil samples, the sorption decreased with decreasing organic matter content and increasing pH. The retention of niobium on soil samples was the most efficient among the studied elements. The retention was high regardless of the aeration conditions. Sorption on humus was smaller. Selenium was retained efficiently on humus. Sorption on mineral soil samples was stronger in aerobic conditions. Sorption increased with time. Technetium was sorbed well on humus and anaerobic, untreated mineral soil samples. Sorption increased with increasing organic matter content and decreasing redox potential. The results from the sorption experiments are used in the site specific radionuclide migration modelling. (orig.)

  18. Retention capacity of the calcium silicates hydrates (CSH) for caesium

    International Nuclear Information System (INIS)

    Alkalis are poorly trapped by cement and this constitutes one of the problem for the use of cement as nuclear waste matrix. Therefore we have studied the sorption of 137Cs on the CSH which are the major components of a Portland cement. CSH of different Ca/Si has been synthetised in suspension. Caesium chloride, which is highly soluble, was placed in a reactor with the CSH. To have a high precision for the caesium quantity fixed by the CSH, radioactive caesium was used as tracer. We observed that the maximum exchange capacity occurs at low Ca/Si ratio, when the structure is close to that of tobermorite. A Cs/Ca molar ratio around one could be obtained in this structure. (orig.)

  19. The utilization of caesium 137 in studying soil degradation

    International Nuclear Information System (INIS)

    The caesium 137 isotope is distributed in the atmosphere during nuclear explosions, and is absorbed in the upper horizons of the soil on reaching the ground. When it is incorporated in the fine fraction of the soil, caesium 137 measurement allows movements affecting cultivated lands (mass movements, runoff effects, wind action) and rate of soil degradation over half a century to be evaluated. Vegetal cover and techniques of soil utilization must be considered; this method has been tested on a watershed in the Parisian Basin. 5 figs., 26 refs

  20. Low Level Caesium Mapping in Latvia Anno 1996

    DEFF Research Database (Denmark)

    Aage, Helle Karina

    1999-01-01

    In Latvia the caesium-137 contamination from the Chernobyl accident and from the nuclear weapon tests in the 1960´es is very low. Conventional techniques for extracting information from the measured spectra cannot be used here. Therefore a new, sensitive technique - the pseudo concentration method...

  1. Low Level Caesium Mapping in Latvia Anno 1995

    DEFF Research Database (Denmark)

    Aage, Helle Karina

    1999-01-01

    In Latvia the caesium-137 contamination from the Chernobyl accident and from the nuclear weapon tests in the 1960´es is very low. Conventional techniques for extracting information from the measured spectra cannot be used here. Therefore a new, sensitive technique - the pseudo concentration method...

  2. The mechanisms of caesium uptake by plants

    International Nuclear Information System (INIS)

    Persistent radioactive isotopes of caesium (134Cs and 137Cs) in the environment are of concern because they impact on both health and commerce. They enter the terrestrial food chain through plants. Plant roots take up Cs+ from the soil solution. To reach the shoot via the xylem, Cs+ must cross the plasma membranes of root cells at least twice. This is catalysed by transport proteins. Since Cs is an alkali metal with chemical properties similar to potassium (K), it has been suggested that the same proteins that transport K+ also transport Cs+. However, the Cs:K ratio in the shoots of different plant species grown under identical conditions varies widely. Since different transport proteins have contrasting abilities to discriminate between Cs+ and K+, this varying Cs:K ratio suggests that a different complement of transport proteins operates in different plant species. In the plasma membrane of root cells inward-rectifying K+ channels (KIRCs), outward-rectifying cation channels (KORCs and NORCs), voltage-independent cation channels (VICCs) and voltage-dependent Ca2+ channels (HACCs and DACCs) are all permeable to Cs+ and K+. In addition, the 'high-affinity' K+/H+ symporters (KUPs) and 'low affinity' transporters, such as the wheat TaLCT1 protein, may also transport Cs+ and K+. The relative abundance and selectivity of these transport proteins in the root plasma membrane will determine the relative fluxes of Cs+ and K+ to the shoot. Theoretical models describing Cs+ fluxes across the plasma membrane of root cells predict that, under natural conditions, VICCs mediate most (30 to 90%) of the Cs+ influx, with KUPs mediating the remainder, Cs+ influx through KIRCs is negligible, and stelar KORCs load Cs+ into the xylem. These predictions are consistent with the identical pharmacology of VICCs and Cs+ uptake by plants, which are both partially inhibited by La3+, Ba2+ or Ca2+ at millimolar concentrations, and the phenotypes of Arabidopsis mutants lacking the dominant root

  3. Study of caesium adsorption on hydrated calcium-silicate-aluminate systems

    International Nuclear Information System (INIS)

    Immobilization of caesium in cementitious matrixes was studied in the present paper which is a key issue of handling radioactive caesium containig wastes for caesium does not form stabile compounds therefor it can not be readily immobilized. Model matrices were prepared to map up the calcium-silicate-aluminate system considering caesium immobilization, which were of different starting compositions. To caracterize Cs sorption, distribution ratios were determined. Based on the results obtained the model matrix compositions were prepared using industrial grade materials and their caesium retardation and trapping were examined by means of leaching and sorption experiments. In the light of the results obtained, it can be established that immobilization of caesium significantly depend on the starting composition of the used matrix. (orig.)

  4. Distribution of Caesium-137 in Samples Consisting of Soft Tissue, Bone and Bone Marrow

    International Nuclear Information System (INIS)

    The investigations which were performed up to now on the distribution of-caesium-137 in the human organism could not explain exactly the distribution of the radiocaesium between bone and bone marrow. That is why a reliable estimation of the radiation burden of the skeleton caused by the incorporation of atmospheric caesium-137 is not given in the literature. Therefore, the concentration of caesium-137 in compact bones as well as in bone marrow was determined. Furthermore, the concentration of caesium-137 in the soft tissue of the same individuals was measured. (author)

  5. Bichromatic State-insensitive Trapping of Caesium Atoms

    OpenAIRE

    Metbulut, M. M.; Renzoni, F.

    2015-01-01

    State-insensitive dipole trapping of multilevel atoms can be achieved by an appropriate choice of the wavelength of the trapping laser, so that the interaction with the different transitions results in equal AC Stark shifts for the ground and excited states of interest. However this approach is severely limited by the availability of coherent sources at the required wavelength and of appropriate power. This work investigates state-insensitive trapping of caesium atoms for which the required w...

  6. Interdigitated electrode array based sensors for environmental monitoring of caesium

    Energy Technology Data Exchange (ETDEWEB)

    Nickson, I D [John Tyndall Nuclear Research Institute and Centre for Materials Science, University of Central Lancashire, Preston PR1 2HE (United Kingdom); Boxall, C [Engineering Department, Lancaster University, Lancaster LA1 4YR (United Kingdom); Port, S N, E-mail: c.boxall@lancaster.ac.uk [DSTL, Salisbury, Wiltshire SP4 0JQ (United Kingdom)

    2010-03-15

    The requirement for on-line and in-situ monitoring of analytes in process and effluent streams and in ground waters has become increasingly more important in recent years. We therefore describe the development of the transduction element for a fully automated online instrument for the detection of caesium. The sensor layer for this instrument employs an Ion Selective Conductimetric Microsensor (ISCOM) as the detector. This is based upon a plasticized polymeric membrane incorporating a selective ionophore, overlaying two interdigitated microelectrode arrays. A direct relationship has been observed between the bulk conductance (as determined by the microelectrodes) of the ionophore loaded membrane and the concentration of the primary ions in solution. Caesium selective ISCOMs were prepared using an ion selective membrane containing the commercially available ionophore Calix [6]arene-hexaacetic acid hexaethyl ester, polyvinylchloride (PVC) and plasticiser Nitrophenylether (NPOE). The relative levels of membrane components have also been varied in order to further enhance the ISCOM response. We also present preliminary data concerning the caesium selectivity with respect to a range of possible interferents, including rubidium.

  7. Interdigitated electrode array based sensors for environmental monitoring of caesium

    Science.gov (United States)

    Nickson, I. D.; Boxall, C.; Port, S. N.

    2010-03-01

    The requirement for on-line and in-situ monitoring of analytes in process and effluent streams and in ground waters has become increasingly more important in recent years. We therefore describe the development of the transduction element for a fully automated online instrument for the detection of caesium. The sensor layer for this instrument employs an Ion Selective Conductimetric Microsensor (ISCOM) as the detector. This is based upon a plasticized polymeric membrane incorporating a selective ionophore, overlaying two interdigitated microelectrode arrays. A direct relationship has been observed between the bulk conductance (as determined by the microelectrodes) of the ionophore loaded membrane and the concentration of the primary ions in solution. Caesium selective ISCOMs were prepared using an ion selective membrane containing the commercially available ionophore Calix [6]arene-hexaacetic acid hexaethyl ester, polyvinylchloride (PVC) and plasticiser Nitrophenylether (NPOE). The relative levels of membrane components have also been varied in order to further enhance the ISCOM response. We also present preliminary data concerning the caesium selectivity with respect to a range of possible interferents, including rubidium.

  8. Chernobyl caesium distribution in two forest soils

    International Nuclear Information System (INIS)

    The Chernobyl nuclear accident on April 26, 1986 affected a considerable part of Europe, including the Romanian territory too. The soil acts as an integrator and the main part of the received radionuclides remains here. However, due to diffusion, leaching and runoff, activity of living organisms in soil, human activity and different other factors, the deposited radionuclides on the soil surface can be removed from the original deposition areas. Mainly, the transport of Cs-137 from soil to other environmental factors is intensively studied having in view the natural resource exploitation in radioactive contaminated areas, this radionuclide being one of the most important radioisotopes released by earlier nuclear weapon tests and nuclear accidents. Generally, migration rates of radionuclides in soil are evaluated by column and percolation experiments, in controlled conditions and using well-defined concentrations of the radionuclide. As part of the environment, the forests have been contaminated up to a depth of 30 cm by the radionuclides resulting from Chernobyl nuclear accident. As the forest is a source of radionuclides for intake and habitat for some critical groups and also a secondary source of contamination (resuspension, erosion), its radioecology became an increasing research topic. The depth distribution of radiocaesium was analysed in the brown-reddish forest type soil of two forests. The depth profile and the specific activity of each layer permit the assessment of total deposition, migration rate and diffusion coefficient for Cs-137 and Cs-134. The total deposition of Cs-137 is about 47 kBq/m2 for Magurele area and about 14 kBq/m2 for Naipu forest. The migration rate is more than 10 times higher in Naipu forest as compared to Magurele forest. The diffusion coefficients are similar, namely about 0.2 cm2/year. (authors)

  9. Chernobyl caesium distribution in two forest soils

    International Nuclear Information System (INIS)

    The Chernobyl nuclear accident on April 26, 1986, affected a considerable part of Europe, including the Romanian territory too. As part of the environment, the forests, covering up to 30 % area of Romania, were contaminated by the radionuclides resulting from Chernobyl nuclear accident. Being a source of radionuclides for intake and habitat for some critical groups and also a secondary source of contamination (resuspension, erosion), forest radioecology is an increasing research topic. The distribution of radiocaesium with depth was analysed in the brown-reddish forest type soil of two forests. The profile with depth and the specific activity of each layer permit the assessment of: total deposition, migration rate and diffusion coefficient for Cs-137 and also Cs-134. The total deposition of Cs-137 is about 47 kBq/m2 for Magurele area and about 14 kBq/m2 for Naipu forest. The migration rate is more than 10 times greater in Naipu forest as in Magurele forest. The diffusion coefficients are similar, about 0.2 cm2/an. (author)

  10. Development of electrokinetic remediation for caesium: A feasibility study of 2D electrode configuration system

    Science.gov (United States)

    Syah Putra, Rudy

    2016-02-01

    Agar matrix was artificially contaminated with caesium and subjected to rapid assessment of electrokinetic treatment on the basis of the 2D electrode configuration. The effect of caesium concentration on the process was investigated using different electrode configuration (i.e. rectangular, hexagonal and triangular). During treatment the in situ pH distribution, the current flow, and the potential distribution were monitored. At the end of the treatment, the caesium concentration distribution was measured. The results of these experiments showed that for caesium contamination, pH control is essential in order to create a suitable environment throughout the agar matrix to enable contaminant removal. It was found that the type of electrode configuration used to control the pH affected the rate of caesium accumulation. All of the electrode configurations tested was effective, but the highest caesium extraction was achieved when the hexagonal pattern was used to control the pH. After 72 h of treatment at 50 mA, the concentration of caesium decreased gradually from the second and first layer of agar matrix throughout the cell, suggesting that most of the caesium was concentrated on the cathode part.

  11. A modified version of the combined in-diffusion/abrasive peeling technique for measuring diffusion of strongly sorbing radionuclides in argillaceous rocks: A test study on the diffusion of caesium in Opalinus Clay

    International Nuclear Information System (INIS)

    A filter free diffusion set-up was developed for measuring the diffusion of strongly sorbing radionuclides in indurated argillaceous rocks such as Opalinus Clay (OPA) that normally disintegrate when contacted with a solution. Small bore cores drilled parallel to the bedding plane and embedded in epoxy resin were found to be stable and could be used for performing in-diffusion measurements. The method was tested with the diffusion of caesium, spiked with caesium-134, in Opalinus Clay. The profile of Cs in the clay sample was determined with a modified version of the abrasive peeling technique. The diffusion parameters obtained for caesium were in fair agreement with those determined earlier using the classical through-diffusion technique where stainless steel filters were used to confine the samples. - Highlights: • We developed a simple method to study diffusion of radionuclides in clay rocks. • We tested the method with diffusion of caesium in Opalinus Clay. • The obtained diffusion parameters are in agreement with previous studies. • The proposed technique forms a step forward for migration studies in clay rock

  12. Highly NO2 sensitive caesium doped graphene oxide conductometric sensors

    OpenAIRE

    Piloto, Carlo; Notarianni, Marco; Shafiei, Mahnaz; Taran, Elena; Galpaya, Dilini; Yan, Cheng; Motta, Nunzio

    2014-01-01

    Here we report on the synthesis of caesium doped graphene oxide (GO-Cs) and its application to the development of a novel NO2 gas sensor. The GO, synthesized by oxidation of graphite through chemical treatment, was doped with Cs by thermal solid-state reaction. The samples, dispersed in DI water by sonication, have been drop-casted on standard interdigitated Pt electrodes. The response of both pristine and Cs doped GO to NO2 at room temperature is studied by varying the gas concentration. The...

  13. High Performance Small Optically Pumped Caesium Beam Frequency Standard

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jian-Wei; YANG Dong-Hai

    2007-01-01

    An experiment of a high performance small optically pumped caesium (Cs) beam frequency standard is reported. An extended cavity diode laser works as the probing laser, of which the frequency is stabilized by the Zeeman modulation method. The running parameters of the frequency standard are dynamically optimized via digital servo electronics. The experimental setup improves the frequency stability up to 1.8 × 10-12 atτ= 1 s and about 1.0 × 10~13 at τ= 105 s (Allan deviation).

  14. Migration of 137Cs and 134Cs in different forest soil layers

    International Nuclear Information System (INIS)

    Caesium-134 and 137Cs measurements in about 250 samples from L-, Of-, Oh-, Ah- and B-horizons of a Bavarian forest from 1987 to 1994 are analysed with respect to migration by using a compartment model. The derived ecological half-lives are 2.8 years, 3.8 years, 4.4 years and 7.7 years, respectively. By using these results, caesium behaviour can be predicted for about 25 years. The resulting profile is similar to that found nowadays for weapons fallout caesium, migrating within about 25 years in the same forest. Therefore, the model is suitable for the estimation of future behaviour of radiocaesium in the forest investigated for a period of about 25 years after deposition. (Author)

  15. Caesium 137 in northern Swedish moose: The first year after the Chernobyl accident

    Energy Technology Data Exchange (ETDEWEB)

    Danell, K.; Nelin, P. (Swedish Univ. of Agricultural Science, Umeaa (Sweden). Dept. of Wildlife Ecology); Wickman, G. (Umeaa Univ. (Sweden). Radiation Physics Dept.)

    1989-01-01

    Levels of /sup 137/ caesium were monitored in northern Sweden during the first year after the Chernobyl accident (April 1986). Samples were collected from 3661 moose in an area where the deposited /sup 137/ caesium ranged from two to 60 kilo-becquerel per m/sup 2/. Concentrations of caesium in moose muscle correlated positively with the ground deposition of caesium. On average, the caesium levels found in moose after Chernobyl were about 470 Bq per kg fresh mass for calves and close to 300 for older animals. The average level in moose before the accident was 33 Bq per kg. Among moose older than one year, higher concentrations were found in females than in the males. There was a pronounced seasonal variation in the /sup 137/ caesium concentration found in moose. Within the investigation area the presence of caesium in moose resulted in a minor proportion of the hunters discarding the animals shot and/or terminating the hunt before the end of the season.

  16. Bichromatic State-insensitive Trapping of Caesium Atoms

    CERN Document Server

    Metbulut, M M

    2015-01-01

    State-insensitive dipole trapping of multilevel atoms can be achieved by an appropriate choice of the wavelength of the trapping laser, so that the interaction with the different transitions results in equal AC Stark shifts for the ground and excited states of interest. However this approach is severely limited by the availability of coherent sources at the required wavelength and of appropriate power. This work investigates state-insensitive trapping of caesium atoms for which the required wavelength of 935.6 nm is inconvenient in terms of experimental realization. Bichromatic state-insensitive trapping is proposed to overcome the lack of suitable laser sources. We first consider pairs of laser wavelengths in the ratio 1:2 and 1:3, as obtained via second- and third- harmonic generation. We found that the wavelength combinations 931.8-1863.6 nm and 927.5-2782.5 nm are suitable for state-insensitive trapping of caesium atoms. In addition, we examine bichromatic state-insensitive trapping produced by pairs of l...

  17. Bichromatic state-insensitive trapping of caesium atoms

    Science.gov (United States)

    Metbulut, M. M.; Renzoni, F.

    2015-12-01

    State-insensitive dipole trapping of multilevel atoms can be achieved by an appropriate choice of the wavelength of the trapping laser, so that the interaction with the different transitions results in equal AC Stark shifts for the ground and excited states of interest. However this approach is severely limited by the availability of coherent sources at the required wavelength and of appropriate power. This work investigates state-insensitive trapping of caesium atoms for which the required wavelength of 935.6 nm is inconvenient in terms of experimental realization. Bichromatic state-insensitive trapping is proposed to overcome the lack of suitable laser sources. We first consider pairs of laser wavelengths in the ratio 1:2 and 1:3, as obtained via second- and third- harmonic generation. We found that the wavelength combinations 931.8-1863.6 nm and 927.5-2782.5 nm are suitable for state-insensitive trapping of caesium atoms. In addition, we examine bichromatic state-insensitive trapping produced by pairs of laser wavelengths corresponding to currently available high power lasers. These wavelength pairs were found to be in the range of 585-588 nm and 623-629 for one laser and 1064-1080 nm for the other.

  18. Isothermal test as a WLR monitor for Cu interconnects

    Science.gov (United States)

    Marathe, Amit P.; Pham, Van; Chan, Jay; Weidner, Jorg-Oliver; Heinig, Volker; Thierbach, Steffi

    2000-08-01

    The need for higher interconnect current densities has been increasing rapidly for advanced integrated circuits. Cu interconnects have emerged as viable candidates to replace Aluminium due to the lower sheet resistivity and increased electro migration lifetime of Cu. Previously, we had reported the use of the isothermal test as a WLR monitor for detecting process defects such as voids in the Aluminium interconnects. This paper further extends the application of the isothermal test methodology for detecting and characterizing process defects in Cu interconnect technology. Package electro migration test are time consuming and may be impractical in detecting process defects in a timely manner. Isothermal test, on the other hand, can be effectively used as a fast WLR process monitor. This paper reports the influence of direction of test current as well as different types of test structures, such as a single level NIST structure and a via chain structure and a via chain structure, on the isothermal test results for Cu interconnects. The isothermal test data has been shown to be helpful in evaluating the location and severity of the process defects through a proper choice of test structures. Joule heating due to high current density is found to be the major driving force for the sensitivity of isothermal test failures. A good correlation is also seen with the package electro migration data. A simple wafer level isothermal test has thus been successfully demonstrated as a reliability tool for process monitoring in Cu VLSI interconnects.

  19. Modelling of radionuclide migration in forest ecosystems. A literature review

    International Nuclear Information System (INIS)

    The Chernobyl accident has clearly shown the long-term effects of a radioactive contamination of forest ecosystems. This report is based on a literature review of models which describe the migration of radionuclides, radioactive caesium in particular, in forest ecosystems. The report describes the particularities of the forest ecosystem, the time dynamics of the contamination, the transfer processes and factors influencing caesium migration. This provides a basis for a discussion of different approaches for modelling caesium migration in the forest. It is concluded that the studied dynamic models include the most relevant transfer processes both for the acute and the long-term phase after a radioactive deposition. However, most models are site specific and do not consider some of the factors responsible for the differences in radionuclide behaviour and distribution in different types of forests. Although model improvements are constrained by the availability of experimental data and by the lack of knowledge of the migration mechanisms some possible improvements are discussed. This report is part of the LANDSCAPE project. -An integrated approach to radionuclide flow in the semi-natural ecosystems underlying exposure pathways to man

  20. Modelling of radionuclide migration in forest ecosystems. A literature review

    Energy Technology Data Exchange (ETDEWEB)

    Avila, R.; Moberg, L.; Hubbard, L.

    1998-03-01

    The Chernobyl accident has clearly shown the long-term effects of a radioactive contamination of forest ecosystems. This report is based on a literature review of models which describe the migration of radionuclides, radioactive caesium in particular, in forest ecosystems. The report describes the particularities of the forest ecosystem, the time dynamics of the contamination, the transfer processes and factors influencing caesium migration. This provides a basis for a discussion of different approaches for modelling caesium migration in the forest. It is concluded that the studied dynamic models include the most relevant transfer processes both for the acute and the long-term phase after a radioactive deposition. However, most models are site specific and do not consider some of the factors responsible for the differences in radionuclide behaviour and distribution in different types of forests. Although model improvements are constrained by the availability of experimental data and by the lack of knowledge of the migration mechanisms some possible improvements are discussed. This report is part of the LANDSCAPE project. -An integrated approach to radionuclide flow in the semi-natural ecosystems underlying exposure pathways to man. 42 refs, 3 tabs, 9 figs.

  1. Crustaceous lichens sensitive monitor of caesium-137 radiation level in terrestrial environment

    Institute of Scientific and Technical Information of China (English)

    Du Chunguang; Zhao Ye; Zhang Jing; Xu Cuihua

    2005-01-01

    The activity of caesium-137 (Bq/kg) in the crustaceous lichens and other samples was determined to prove the feasibility that crustaceous lichens work as a sensitive biology monitor to record the caesium-137 (Bq/kg) radiation levels of terrestrial environment. The measurements were performed with GEM series HPGe (high-purity Germanium) coaxial detector system (ADCAM -100) made by EC & GORTEC Company in USA. It was found that the activity of caesium-137 (Bq/kg) in the crustaceous lichens was one order of magnitude higher than that found in surface soil,and was over three orders of magnitude higher than those found in the familiar biological samples. These results proved that crustaceous lichens may be one of the most sensitive biological monitors about the remote transmission and environmental radiation levels of caesium-137.

  2. Density functional theory metadynamics of silver, caesium and palladium diffusion at β-SiC grain boundaries

    Energy Technology Data Exchange (ETDEWEB)

    Rabone, Jeremy, E-mail: jeremy.rabone@ec.europa.eu [European Commission, Joint Research Centre, Institute for Transuranium Elements, D-76125 Karlsruhe (Germany); López-Honorato, Eddie [Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV), Unidad Saltillo, Industria Metalúrgica 1062, Parque Industrial, Ramos Arizpe 25900, Coahuila (Mexico)

    2015-03-15

    Highlights: • DFT metadynamics of diffusion of Pd, Ag and Cs on grain boundaries in β-SiC. • The calculated diffusion rates for Pd and Ag tally with experimental release rates. • A mechanism of release other than grain boundary diffusion seems likely for Cs. - Abstract: The use of silicon carbide in coated nuclear fuel particles relies on this materials impermeability towards fission products under normal operating conditions. Determining the underlying factors that control the rate at which radionuclides such as Silver-110m and Caesium-137 can cross the silicon carbide barrier layers, and at which fission products such as palladium could compromise or otherwise alter the nature of this layer, are of paramount importance for the safety of this fuel. To this end, DFT-based metadynamics simulations are applied to the atomic diffusion of silver, caesium and palladium along a Σ5 grain boundary and to palladium along a carbon-rich Σ3 grain boundary in cubic silicon carbide at 1500 K. For silver, the calculated diffusion coefficients lie in a similar range (7.04 × 10{sup −19}–3.69 × 10{sup −17} m{sup 2} s{sup −1}) as determined experimentally. For caesium, the calculated diffusion rates are very much slower (3.91 × 10{sup −23}–2.15 × 10{sup −21} m{sup 2} s{sup −1}) than found experimentally, suggesting a different mechanism to the simulation. Conversely, the calculated atomic diffusion of palladium is very much faster (7.96 × 10{sup −11}–7.26 × 10{sup −9} m{sup 2} s{sup −1}) than the observed penetration rate of palladium nodules. This points to the slow dissolution and rapid regrowth of palladium nodules as a possible ingress mechanism in addition to the previously suggested migration of entire nodules along grain boundaries. The diffusion rate of palladium along the Σ3 grain boundary was calculated to be slightly slower (2.38 × 10{sup −11}–8.24 × 10{sup −10} m{sup 2} s{sup −1}) than along the Σ5 grain boundary. Rather

  3. Caesium immobilization in hydrated calcium-silicate-aluminate systems

    International Nuclear Information System (INIS)

    A special field of application of cementitious materials in using cements for immobilization of low and medium level radioactive wastes. Clarification of mechanisms of binding is complicated by the multicomponent nature of the solidifying matrix. In the present work, interest is turned to one of the most difficult to confine, long half-life isotopes, the caesium isotope. The cement matrix for solidification of the radioactive waste can be considered, with simplification, as a CaO-SiO2-Al2O3-H2O system. The various compositions of hydrated cementitious assemblages were investigated with respect to their Cs sorption by measuring the Cs distribution ratios (Rd) therein. Trends in sorption properties were detected, and the section of the ternary phase diagram with the best performance was identified

  4. Observation of EIA in closed and open caesium atomic system

    Institute of Scientific and Technical Information of China (English)

    Zhao Jian-Ming; Zhao Yan-Ting; Huang Tao; Xiao Lian-Tuan; Jia Suo-Tang

    2005-01-01

    We present an experimental study on electromagnetically induced absorption (EIA) in the closed transition of a degenerate two-level Cs atomic system. The coupling and probe lasers coupled with the transition 6S1/2F=4 →6P3/2F'=5 of caesium atom. The signal of EIA was obtained and the frequency detuning and intensity effect of the pumping laser were experimentally investigated. The EIA signal in 6S1/2 F=4 → 6P3/2 F'=4 and 6S1/2 F=4 → 6P3/2F'=3 open transitions was also obtained. As the repumping laser couples with the transition of 6S1/2 F=3 → 6P3/2F'=4, the EIA signal is increased due to the hyperfine optical pumping.

  5. Caesium extraction by calixarene molecules: Some aspects of extraction kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Simon, N.; Tournois, B.; Volle, G

    2004-07-01

    In the framework of the environment Code (2000 studies were developed to recover long-lived fission products (F.P.) from acidic highly radioactive effluents issuing the reprocessing of spent fuels, to destroy them by transmutation or to encapsulate them into specific matrices. Efforts had been directed towards caesium, particularly {sup 135}Cs, which is one of the most harmful fission products because of its long half life (more than 2.10{sup 6} years) and its mobility in repository. The flow-sheet will be included in the general scheme of long-lived radionuclide partitioning. It was decided to define a process based on liquid-liquid extraction. Crown-calixarenes molecules were chosen for process development. To refine the flowsheet diagram, it is necessary to know the rate constants of the implied chemical reactions involved in the extraction. This paper describes the first determination of rate constant in the Cs extraction with crown calixarenes. (authors)

  6. Highly NO2 sensitive caesium doped graphene oxide conductometric sensors

    Directory of Open Access Journals (Sweden)

    Carlo Piloto

    2014-07-01

    Full Text Available Here we report on the synthesis of caesium doped graphene oxide (GO-Cs and its application to the development of a novel NO2 gas sensor. The GO, synthesized by oxidation of graphite through chemical treatment, was doped with Cs by thermal solid-state reaction. The samples, dispersed in DI water by sonication, have been drop-casted on standard interdigitated Pt electrodes. The response of both pristine and Cs doped GO to NO2 at room temperature is studied by varying the gas concentration. The developed GO-Cs sensor shows a higher response to NO2 than the pristine GO based sensor due to the oxygen functional groups. The detection limit measured with GO-Cs sensor is ≈90 ppb.

  7. Highly NO2 sensitive caesium doped graphene oxide conductometric sensors.

    Science.gov (United States)

    Piloto, Carlo; Notarianni, Marco; Shafiei, Mahnaz; Taran, Elena; Galpaya, Dilini; Yan, Cheng; Motta, Nunzio

    2014-01-01

    Here we report on the synthesis of caesium doped graphene oxide (GO-Cs) and its application to the development of a novel NO2 gas sensor. The GO, synthesized by oxidation of graphite through chemical treatment, was doped with Cs by thermal solid-state reaction. The samples, dispersed in DI water by sonication, have been drop-casted on standard interdigitated Pt electrodes. The response of both pristine and Cs doped GO to NO2 at room temperature is studied by varying the gas concentration. The developed GO-Cs sensor shows a higher response to NO2 than the pristine GO based sensor due to the oxygen functional groups. The detection limit measured with GO-Cs sensor is ≈90 ppb. PMID:25161842

  8. Influence of arbuscular mycorrhizal fungi and the expression of K+/Cs+ transporters on the accumulation of caesium by plants

    OpenAIRE

    Wiesel, Lea

    2011-01-01

    Radiocaesium (134Cs, 137Cs) is of environmental concern because of its incorporation into the food chain and prolonged emission of harmful radiation. Plants take up caesium via cation transporters which cannot discriminate between radioactive and stable caesium (133Cs). Around 80% of angiosperms live in symbiosis with arbuscular mycorrhizal (AM) fungi that deliver mineral nutrients to their hosts. Contrasting effects of AM fungi on caesium accumulation by plants have been reported. The ultima...

  9. The behaviour of fission product caesium in LMFBR primary circuits: experiments in a small stainless steel loop containing circulating sodium

    International Nuclear Information System (INIS)

    The available information which can be used to determine the likely behaviour of fission product caesium, released from defective fuel pins, in the primary circuit of a sodium-cooled fast reactor has been reviewed and assessed. For a relatively small number of fuel pin failures over a reactor lifetime 137Cs is potentially a predominant contributor to dose rates on out-of-core steel components if the adsorption of caesium on these components is sufficiently high. Shortcomings are identified in the existing data on caesium adsorption from liquid sodium onto austenitic steel surfaces. This has enabled the definition of those areas of work which are necessary before the behaviour of fission product caesium in the primary circuit, and the possible requirement of any alleviatory measures, can be predicted with precision and confidence. Experiments are described from which the mechanism of adsorption of caesium onto steel surfaces was elucidated, thereby enabling the prediction of the likely sorption behaviour of fission product caesium on components in the primary circuits of LMFBRs. The potential use of cold-trapping as a means of removing caesium from sodium was also investigated and found to be of no significant value; alternative methods for caesium removal are discussed. The development of methods for decontamination of steelwork which has become contaminated by caesium sorption onto chromium (III) oxides is described, although it is not clear that the levels of contamination which would arise by this mechanism under normal LMFBR operating conditions would necessitate such treatment. (author)

  10. Isothermal Gaseous Detonation Model

    Science.gov (United States)

    Prokhorov, E. S.

    2015-05-01

    We propose an isothermal gaseous detonation model taking into account the initial pressure of the explosive mixture that permits describing in a simplified form both the self-sustaining and the supercompressed and undercompressed detonation regimes. The exactness of this model has been estimated on the basis of a comparative analysis with the results of equilibrium calculations of the gas-dynamic parameters at the front of detonation waves.

  11. Uptake and retention of radio-caesium in earthworms cultured in soil contaminated by the Fukushima nuclear power plant accident.

    Science.gov (United States)

    Fujiwara, K; Takahashi, T; Nguyen, P; Kubota, Y; Gamou, S; Sakurai, S; Takahashi, S

    2015-01-01

    To understand the effects of radionuclides on non-human biota and the environment, it is essential to study the intake and metabolism of radio-isotopes in earthworms which are among the most important soil organisms, and Eisenia fetida, which were used in this study, are known to be sufficiently sensitive to chemicals and representative of common earthworms. In this study, we assessed the concentration ratios, uptake and retention, absorbed dose rate, and distribution of radio-caesium in earthworms. The concentration ratios of (137)Cs (i.e., the concentrations of radio-caesium in earthworms relative to those in dry soil) were higher early in the culturing period and decreased gradually over the experimental period. (137)Cs taken up by E. fetida was cleared rapidly after the worms were cultured in radio-caesium-free soil, suggesting that the metabolism of radio-caesium in earthworms is very rapid. Autoradiography demonstrated that the concentration of radio-caesium within the digestive tract was as high as that in the soil, while radio-caesium in the body tissue was lower than radio-caesium in the soil and was almost uniformly distributed among earthworm tissues. The highest absorbed dose rate of total exposure to radio-caesium ((137)Cs + (134)Cs) was calculated to be 1.9 × 10(3) (μGy/day) in the earthworms. PMID:25464049

  12. DECOMMISSIONING OF A CAESIUM-137 SEALED SOURCE PRODUCTION FACILITY

    Energy Technology Data Exchange (ETDEWEB)

    Murray, A.; Abbott, H.

    2003-02-27

    Amersham owns a former Caesium-137 sealed source production facility. They commissioned RWE NUKEM to carry out an Option Study to determine a strategy for the management of this facility and then the subsequent decommissioning of it. The decommissioning was carried out in two sequential phases. Firstly robotic decommissioning followed by a phase of manual decommissioning. This paper describes the remote equipment designed built and operated, the robotic and manual decommissioning operations performed, the Safety Management arrangements and summarizes the lessons learned. Using the equipment described the facility was dismantled and decontaminated robotically. Some 2300kg of Intermediate Level Waste containing in the order of 4000Ci were removed robotically from the facility. Ambient dose rates were reduced from 100's of R per hour {gamma} to 100's of mR per hour {gamma}. The Telerobotic System was then removed to allow man access to complete the decommissioning. Manual decommissioning reduced ambient dose rates further to less than 1mR per hour {gamma} and loose contamination levels to less than 0.25Bq/cm2. This allowed access to the facility without respiratory protection.

  13. Autler-Townes doublet in novel sub-Doppler spectra with caesium vapour cell

    Institute of Scientific and Technical Information of China (English)

    Wang Yan-Hua; Yang Jai-Jing; Du Zhi-Jing; Zhang Tian-Cai; Wang Jun-Min

    2006-01-01

    With a coupling laser locked to caesium 6S1/2 Fg=4-6P3/2Fe=5 cycling transition and a co-propagating probe laser scanned across 6S1/2Fg=4-6P3/2Fe=3, 4 and 5 transitions, a novel scheme for sub-Doppler spectra in Doppler-broadened V-type three-level system is demonstrated by detecting the transmission of the coupling laser through a caesium vapour cell. The Autler-Townes doublet in the sub-Doppler spectra of the coupling laser is clearly observed. The effects of coupling laser intensity on the splitting and linewidth of the Autleraking the multiple hyperfine levels of caesium atom into account, a brief analysis is presented.

  14. Clinical results in carcinoma of the cervix: radium compared to caesium using remote afterloading.

    Science.gov (United States)

    Jackson, S M; Fairey, R N; Kornelsen, R O; Young, M E; Wong, F L

    1989-05-01

    In 1979 the Cancer Control Agency of British Columbia changed from radium to remote controlled afterloaded caesium in the treatment of carcinoma of the cervix. In the 3 years prior to the change, 139 patients received radium as part of their treatment and in the 3 years after the change, 158 patients received caesium. Overall referral patterns, patient and cancer demographics, and treatment policies were stable throughout the 6-year period. Radiotherapy technique, dose, dose distribution and dose rate were comparable for both radium and caesium treated patients. The results of treatment in the two time periods showed no difference in survival, local tumour control or complications. The use of afterloading has not compromised treatment results and has allowed better nursing care for patients and protection from radiation for all staff. PMID:2752690

  15. Investigations on caesium 134 and 137 contamination of game hunted for food in Hessia

    International Nuclear Information System (INIS)

    The amount of caesium 134 and 137 in Hessian game hunted for food (556 animals) after the reactor accident at Chernobyl was investigated. Comparisons have been made before and after the accident. Although there was only a very low level of contamination, the contamination rate of different species varied; on average, the Red Deer showed the highest activity (130 Bq/kg). The level of caesium contamination was mostly influenced by the permanent habitat of the animals. The main influence was due to regional, geographical and meteorological conditions. The influence of age or sex could not be determined. The contamination rate was shown to decrease with time

  16. Kinetics of caesium and potassium absorption by roots of three grass pastures and competitive effects of potassium on caesium uptake in Cynodon sp.

    Science.gov (United States)

    Ayub, J. Juri; Valverde, L. Rubio; Garcia-Sanchez, M. J.; Fernandez, J. A.; Velasco, R. H.

    2008-08-01

    Caesium uptake by plant roots has been normally associated with the uptake of potassium as the potassium transport systems present in plants have also the capacity to transport caesium. Three grass species (Eragrostis curvula, Cynodon sp and Distichlis spicata) growing in seminatural grassland of central Argentina were selected to study their capability to incorporate Cs+ (and K+) using electrophysiological techniques. Although the 137Cs soil inventory ranged between 328-730 Bq m-2 in this region, no 137Cs activity was detected in these plants. However, all the species, submitted previously to K+ starvation, showed the uptake of both Cs+ and K+ when micromolar concentrations of these cations were present in the medium. The uptake showed saturation kinetics for both cations that could be fitted to the Michelis-Menten model. KM values were smaller for K+ than for Cs+, indicating a higher affinity for the first cation. The presence of increasing K+ concentrations in the assay medium inhibited Cs+ uptake in Cynodon sp., as expected if both cations are transported by the same transport systems. This effect is due to the competition of both ions for the union sites of the high affinity potassium transporters. In field situation, where soil concentration of Cs+ is smaller than K+ concentration, is then expectable that caesium activity in plants is not detectable. Nevertheless, the studied plants would have the capacity to incorporate caesium if its availability in soil solution increases. In addition, studies of Cs/K interaction can help us to understand the variability in transfer factors.

  17. The selectivity of zirconium phosphate for caesium in electrochemical ion exchange

    International Nuclear Information System (INIS)

    The properties of amorphous zirconium phosphate are investigated as an inorganic ion exchanger for use in liquid waste treatment by electrochemical ion exchange. Experiments to determine and increase the selectivity for caesium exchange over sodium are discussed, including various pulsed waveforms and studies with rotating membranes. Automation of a sampling system with pH and atomic absorption measurements is described. (author)

  18. Theoretical calculations of primary particle condensation for cadmium and caesium iodide vapours

    International Nuclear Information System (INIS)

    This report considers a model of aerosol nucleation from the vapour phase which has been developed by Buckle. The applicability of the model has been tested by considering the condensation of caesium iodide and cadmium vapours under a wide variety of pre-mixed flow conditions of interest to PWR severe accident studies. (U.K.)

  19. Caesium activity in nursing mothers and in the mother's milk one year after Chernobyl accident

    International Nuclear Information System (INIS)

    Linear correlation between Cs-137 concentration in mother's milk and the mother's Cs-137 whole body activity was obtained. A simple metabolic model is proposed to interpret measured data. Caesium activity in mother's milk was five times lower than in dairy products. (orig./HP)

  20. The use of bentonite and zeolite as caesium-binders in feed to reindeer - experiences from Sweden

    Directory of Open Access Journals (Sweden)

    Birgitta Åhman

    1990-09-01

    Full Text Available Feeding is used in Sweden to lower radiocaesium levels in reindeer before slaughter. In feeds used for this purpose, bentonite is added as a caesium-binder to prevent absorption of radiocaesium, since the animals usually have som access to contaminated pasture in their corrals. Bentonite is efficient as a caesium-binder but increases water consumption and excretion of urine. Zeolite has been used as a caesium-binder to reindeer in a few experiments. The effect, however, has been inferior to that of bentonite. It seems that zeolite, mixed in feeds, loose some of its effect as the feed is stored. The need of a caesium-binder is demonstrated by results from practical feeding of reindeer where radiocaesium levels have not decreased as expected when feed without bentonite has been used.

  1. Availability of caesium radionuclides to plants - classification of soils and role of mycorrhiza

    Energy Technology Data Exchange (ETDEWEB)

    Drissner, J.; Buermann, W.; Enslin, F.; Heider, R.; Klemt, E.; Miller, R.; Schick, G.; Zibold, G. [Fachhochschule Ravensburg-Weingarten, D-88241 Weingarten (Germany)

    1998-10-01

    At different locations in spruce stands spread rather homogeneously over southern Baden-Wuerttemberg, samples of soil and plants were taken and the vertical distribution of the caesium radionuclides in the soil was studied. As a direct measure of the bioavailability, the aggregated transfer factor, T{sub ag}, was determined for fern, bilberry, raspberry, blackberry, and clover. The T{sub ag} (in m2 kg{sup -1}) is defined by the specific caesium activity (in Bq kg{sup -1}) of the dry mass of the plants, divided by the total inventory (in Bq m{sup -2}) of the soil. It varies between 0{center_dot}5 and 0{center_dot}001 m2kg{sup -1}, being highest for fern and lowest for blackberry or clover at all sampling sites. Most decisive for the value of the T{sub ag} are kind of humus deposit, thickness and pH value of the humus layers. Also important are the soil properties, whereas geology has only a minor influence on T{sub ag}. At different sampling sites in spruce forests, the T{sub ag} can vary by two orders of magnitude for one plant species. Caesium desorption experiments were performed. We could not find a dependence of the transfer of caesium to the plant on the desorbability of caesium from the soil, which implies a more complex transport mechanism than simple ion exchange in the soil solution. It is suggested that the transport of caesium is mediated by mycorrhiza fungi. Therefore, we studied the density of mycorrhiza hyphae in the O{sub f}, O{sub h} and A{sub h} soil horizons of two sites differing in T{sub ag} by a factor of 10. The densities of mycorrhiza hyphae in the O{sub h} and A{sub h} soil horizons each differ by a factor of 2 for the two sites. Yet, the effect of the hyphae density on radiocaesium uptake has to be a subject of further investigation. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  2. New ion selective materials. Application to the selective extraction of caesium

    International Nuclear Information System (INIS)

    This research thesis addresses the synthesis and assessment of ion selective materials. The first part reports the development of a general method of assessment of ion selective materials. In the second part, the author describes different methods used to insolubilize macro-cycles on hydrophilic polymers. The obtained polyurethanes are synthesised. These hydrophilic polymers display interesting complexing properties and selectivities with respect to cations of alkali metals. Then the author addresses the improvement of selectivity with respect to caesium of ion exchange resorcinol-formaldehyde resins. Different factors affecting selectivity are identified, and the concept of molecular print is used to study the improvement of selectivity. The effect of macro-cyclic structures on phenolic resins with respect to caesium is highlighted

  3. Joint monitoring of hydrosedimentological events and transport of caesium 137 in a small basin

    Energy Technology Data Exchange (ETDEWEB)

    Preti, F.; Lubello, C.; Becchi, I. (Florence Univ. (Italy). Dept. of Civil Engineering)

    1993-01-01

    Research was carried out to analyse the transport of Caesium 137 in a small calcareous watershed (3.6 Km[sup 2]) of the Tuscan Appennines (Central Italy). The presence of the radionuclide 137 Cs, adsorbed by the soil, is due to the nuclear tests in the 1960s-70s and to the Chernobyl disaster in 1986. For representation of the transport dynamics of 137 Cs a distributed parameters model has been developed, in order to consider the variability of the physical characteristics of the area. The results of the simulation, compared with the concentrations of Caesium measured by a devised experimental method in the lake-sediments of a hill catchment placed in the closing section of the basin, showed an excellent agreement. (author).

  4. Psychosocial aspects of the victims of the accident with caesium-137 in Goiania (1987-1994)

    International Nuclear Information System (INIS)

    In September of 1987 two men took possession of and violated a source containing Caesium-137, which caused the Radiological Accident of Goiania. Besides the direct victims, a significant part of the community of Goiania was directly involved with this accident. The psychosocial impact in the social groups involved in this radiological accident - the population as a whole, immediate neighbours of contaminated sites, professionals and the victims themselves - gave rise to specific behaviour and attitudes which will be discussed in this paper. (author)

  5. Inferring ecological separation from regional differences in radioactive caesium in harbour porpoises Phocoena phocoena

    OpenAIRE

    Tolley, Krystal A; Heldal, Hilde Elise

    2002-01-01

    Geographic variation in the level of radioactive caesium-137 (Cs-137) was examined from the axial muscle of 36 harbour porpoises Phocoena phocoena obtained as bycatch from 5 locations along the coast of Norway, ranging from southern (North Sea) to northern (Barents Sea) Norway. Levels of Cs-137 in seawater and sediments have been found to differ along the coast of Norway due to distance from point sources, such as the Sellafield nuclear fuel reprocessing plant in Cumbria, UK (discharging into...

  6. Body concentration of caesium-137 in patients from Western Isles of Scotland.

    OpenAIRE

    Isles, C G; Robertson, I.; MacLeod, J A; Preston, T; East, B W; Hole, D J; Lever, A. F.

    1991-01-01

    OBJECTIVES--To compare caesium-137 concentrations in patients from the Western Isles Health Board, Glasgow area, and other parts of the Scottish mainland, and to investigate the source of 137Cs in patients from the Western Isles. DESIGN--Study of hypertensive patients having electrolyte concentrations measured, including 137Cs. Interview by questionnaire of island subjects about intake of foods likely to contain radiocaesium and the source of these foods. Measurement of 137Cs and 134Cs in foo...

  7. Caesium 137 in meat from reindeer and grouses from Svaldbard 1980

    Energy Technology Data Exchange (ETDEWEB)

    Kjos-Hanssen, B.; Rennesund, J.S. (Forsvarets Forskningsinstitutt, Kjeller (Norway))

    1981-01-01

    Concentration of Caesium 137 in meat from Spitsbergen (Svalbard) and mainland Norway reindeer has been measured. It appears that the concentration values for Spitsbergen are of the order of 1 per cent of corresponding values for the mainland. It is suggested that low precipitation rates and a different reindeer diet contributes to the low Cs 137 concentration values in Svaldbard. The concentration of Cs 137 in Svaldbard grouse did not exceed the detection limit of the measurements (approximately 10 pCi/kg).

  8. (Caesium 137 in meat from reindeer and grouse from Svalbard 1980 (author's transl))

    Energy Technology Data Exchange (ETDEWEB)

    Kjos-Hanssen, B.; Rennesund, J.S.

    Concentration of Caesium 137 in meat from Spitsbergen (Svalbard) and mainland Norway reindeer has been measured. It appears that the concentration values for Spitsbergen are of the order of 1 per cent of corresponding values for the mainland. It is suggested that low precipitation rates and a different reindeer diet contributes to the low Cs 137 concentration values in Svalbard. The concentration of Cs 137 in Svalbard grouse did not exceed the detection limit of the measurements (infinity 10 pCi/kg).

  9. Return migration.

    Science.gov (United States)

    Gmelch, G

    1980-01-01

    The author reviews the findings of the growing literature on return migration. Topics covered include typologies of return migrants, reasons for return, adaptation and readjustment of returnees, and the impact of return migration on the migrants' home societies. The focus of the study is on international return migration, migration to Northern Europe and northeastern North America, and return migration to the southern and eastern fringes of Europe and the Caribbean

  10. Isothermal and Near Isothermal Processing of Titanium Alloys

    Directory of Open Access Journals (Sweden)

    T. Raghu

    2011-01-01

    Full Text Available Isothermal and near isothermal forging are specialized metal processing techniques which are used for producing critical aeroengine components out of advanced materials such as titanium alloys. The process can be used to produce net / near net shape components leading to optimum utilization of materials. As titanium alloys are highly sensitive to temperature and strain rate, these processes help to deform them under slow and controlled strain rates.  Further, these processes can be combined with other conventional and non conventional metal forming processes to refine the microstructure. For example, multiaxial isothermal forging coupled with pack rolling can be used to produce thin sheets out of titanium alloys with submicron grain size. The refined structure exhibits superplastic characteristics at low temperatures and high strain rates. This lower temperature superplastic characteristic can be exploited to establish technologies for producing various components. The paper throws light on the capabilities of isothermal forging process and its variants.Defence Science Journal, 2011, 61(1, pp.72-80, DOI:http://dx.doi.org/10.14429/dsj.61.321

  11. Experimental study on the possibilities of direct transfer of caesium 137 from sediment to the carps (Cyprinus carpio L. )

    Energy Technology Data Exchange (ETDEWEB)

    Lambrechts, A.; Foulquier, L.

    1983-06-01

    The exchanges of caesium 137 with the Rhone river water and deposits and its direct transfer from water and deposits to the carp are studied. The sediments have a high retention capacity for radiocaesium associated with fine particles and certain clays (illite). Caesium desorption from sediment to water is always very weak (less than 5% of the initial activity of the sediments; it varies with the agitation and salinity of the water. The transfer of caesium from the water to the carps is characterized by a regular increase of activity in the fish. After 63 days of experimentation, equilibrium has not been reached, the carp have retained only 1% of the water activity, and their concentration factor is about 4. The transfer of caesium from sediment to the fish is weak but regular. After 79 days of experimentation, equilibrium has not been reached. Less than 1% of the sediments activity is found in the fish; the transfer factor is about 10/sup -3/. Because of the high content of caesium 137 in sediments, the activity of the carp is increased and the concentration factor, calculated in relation to the surface water, is greater than 60.

  12. Comparison of caesium 137 and 134 activity in sheep remaining on upland areas contaminated by Chernobyl fallout with those removed to less active lowland pasture

    Energy Technology Data Exchange (ETDEWEB)

    Howard, B.J.; Beresford, N.A.; Burrow, L.; Shaw, P.V.; Curtis, E.J.C.

    Caesium contamination of vegetation in some upland areas of the United Kingdom after the Chernobyl accident remained persistently higher than many anticipated. Consequently, some sheep continued to graze vegetation containing sufficiently high caesium activity to maintain tissue activity above the limits adopted for slaughter in the United Kingdom (1,000 Bq kg/sup -1/ fresh weight). In this study the caesium activity in lambs remaining on affected upland areas has been compared with that of lambs removed to a lowland site. The former lost very little caesium activity from the end of July to mid-September owing to the persistently high caesium activity of the pasture. The transfer coefficient to lamb muscle (0.79 day kg/sup -1/) was 6 times higher than that previously estimated from lowland field studies. Lambs removed to much less contaminated lowland pasture rapidly lost their Cs activity with an initial biological half life of 10 days.

  13. BINDING ISOTHERMS SURFACTANT-PROTEINS

    OpenAIRE

    Elena Irina Moater; Cristiana Radulescu; Ionica Ionita

    2011-01-01

    The interactions between surfactants and proteins shows some similarities with interactions between surfactants and polymers, but the hydrophobic amphoteric nature of proteins and their secondary and tertiary structure components make them different from conventional polymer systems. Many studies from the past about surfactant - proteins bonding used the dialysis techniques. Other techniques used to determine the binding isotherm, included ultrafiltration, ultracentrifugation, potentiometry, ...

  14. Patients blood serum ferritin concentrations changes associated with Caesium-137 incorporation

    International Nuclear Information System (INIS)

    The results of radioimmune study of ferritin and carcinoembryonic antigen in 60 persons: 35 those who took part in liquidation of the Chernobyl accident and incorporated 25.9-70.4 MBq of Cesium-137,25 residents of Rivno Region with 7.4-203.5 MBq of the radionuclide in the organism are reported. The increased concentration of ferritin and carcinoembryonic antigen in blood serum was noted to be determined more often in the residents of the areas polluted with Caesium-137 than in liquidators. The tumor markers levels depended to some extent on bad habits (smoking, alcohol) and existing chronic diseases of the alimentary system

  15. Absorption spectroscopy of cold caesium atoms confined in a magneto-optical trap

    Institute of Scientific and Technical Information of China (English)

    Yan Shu-Bin; Liu Tao; Geng Tao; Zhang Tian-Cai; Peng Kun-Chi; Wang Jun-Min

    2004-01-01

    Absorption spectra of cold caesium atoms confined in a magneto-optical trap are measured around D2 line at 852nm with a weak probe beam. Absorption reduction dip due to electromagnetically induced transparency (EIT)effect induced by the cooling/trapping field in a V-type three-level system and a gain peak near the cycling transition are clearly observed. Several mechanisms mixed with EIT effect in a normal V-type three-level system are briefly discussed. A simple theoretical analysis based on a dressed-state model is presented for interpretation of the absorption spectra.

  16. Orofacial manifestations from accidental exposure to caesium 137 in Goiania, Brazil.

    Science.gov (United States)

    Gomes, M A; Wascheck, C de C; Scully, C; Almeida, O de P; Bozzo, L

    1990-08-01

    The accidental close exposure of over 200 adults and children to a caesium-137 (137Cs) source in Goiania, Brazil in 1987 produced significant short-term morbidity in about 50 patients, and four deaths within a few weeks. Some 57% of those maximally exposed to radiation, developed orofacial lesions, notably purpura, spontaneous bleeding, ulcers and/or acute candidiasis. These lesions were probably mainly the consequences of depression of bone marrow elements by the radionuclide. Though the oral lesions that may follow iatrogenic exposure to ionizing radiation are well recognized this appears to be the first report on the oral sequelae of a serious radiation accident.

  17. The fate of caesium-137 in a soil environment controlled by immobilization on clay minerals

    OpenAIRE

    NAKAO, Atsushi; Funakawa, Shinya; Tsukada, Hirofumi; Kosaki, Takashi

    2012-01-01

    Caesium-137 (137Cs), with its high release rate and long half life, is the most important longterm contributor to environmental contamination of all the radionuclides released by the accident at the Fukushima Dai-ichi nuclear power plant in March 2011. There have been many surveys of the fate of 137Cs in terrestrial environments, especially after the atmospheric nuclear tests of the 1950s and 60s and the Chernobyl accident in 1986. Previous surveys revealed that most of the 137Cs deposited on...

  18. Isolation and identification of cobalt and caesium resistant bacteria from a nuclear fuel storage pond.

    OpenAIRE

    Dekker, L.; Osborne, T. H.; Santini, J. M.

    2014-01-01

    One of the issues facing the nuclear power industry is how to store spent nuclear fuel which is contaminated with radionuclides produced during nuclear fission, including caesium ((134) Cs(+) , (135) Cs(+) and (137) Cs(+) ) and cobalt ((60) Co(2+) ). In this study we have isolated Co(2+) and Cs(+) resistant bacteria from water collected from a nuclear fuel storage pond. The most resistant Cs(+) and Co(2+) isolates grew in the presence of 500 mM CsCl and 3 mM CoCl2 . Strain Cs67-2 is resistant...

  19. Poly[μ3-aqua-aqua-μ5-(4-nitro­benzoato)-caesium

    OpenAIRE

    Graham Smith

    2013-01-01

    In the structure of the title complex, [Cs(C7H4NO2)(H2O)2]n, the caesium salt of 4-nitrobenzoic acid, the irregular CsO9 coordination sphere comprises three bridging nitro O-atom donors, a bidentate carboxylate O,O′-chelate interaction, a triple-bridging water molecule and a monodentate water molecule. A three-dimensional framework polymer is generated, within which there are water–carboxylate O—H...O and water–water O—H...O hydrogen-bonding interactions.

  20. Animated molecular dynamics simulations of hydrated caesium-smectite interlayers

    Directory of Open Access Journals (Sweden)

    Sposito Garrison

    2002-09-01

    Full Text Available Computer animation of center of mass coordinates obtained from 800 ps molecular dynamics simulations of Cs-smectite hydrates (1/3 and 2/3 water monolayers provided information concerning the structure and dynamics of the interlayer region that could not be obtained through traditional simulation analysis methods. Cs+ formed inner sphere complexes with the mineral surface, and could be seen to jump from one attracting location near a layer charge site to the next, while water molecules were observed to migrate from the hydration shell of one ion to that of another. Neighboring ions maintained a partial hydration shell by sharing water molecules, such that a single water molecule hydrated two ions simultaneously for hundreds of picoseconds. Cs-montmorillonite hydrates featured the largest extent of this sharing interaction, because interlayer ions were able to inhabit positions near surface cavities as well as at their edges, close to oxygen triads. The greater positional freedom of Cs+ within the montmorillonite interlayer, a result of structural hydroxyl orientation and low tetrahedral charge, promoted the optimization of distances between cations and water molecules required for water sharing. Preference of Cs+ for locations near oxygen triads was observed within interlayer beidellite and hectorite. Water molecules also could be seen to interact directly with the mineral surface, entering its surface cavities to approach attracting charge sites and structural hydroxyls. With increasing water content, water molecules exhibited increased frequency and duration of both cavity habitation and water sharing interactions. Competition between Cs+ and water molecules for surface sites was evident. These important cooperative and competitive features of interlayer molecular behavior were uniquely revealed by animation of an otherwise highly complex simulation output.

  1. Venus: an isothermal lower atmosphere?

    Science.gov (United States)

    Gale, W; Liwshitz, M; Sinclair, A C

    1969-05-30

    Use of Earth-based microwave data in extrapolating the atmospheric profile of Venus below the region probed by Mariner V and Venera 4 reveals an isothermal layer at 670 degrees +/- 20 degrees K that extends to an altitude of 7 +/- 2 kilometers. This model gives a value of 6054.8 kilometers for the radius of Venus, and agreement with brightness spectrum, radar cross sections, and results of microwave interferometry.

  2. Adsorption isotherm special study. Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1993-05-01

    The study was designed to identify methods to determine adsorption applicable to Uranium Mill Tailings Remedial Action (UMTRA) Project sites, and to determine how changes in aquifer conditions affect metal adsorption, resulting retardation factors, and estimated contaminant migration rates. EPA and ASTM procedures were used to estimate sediment sorption of U, As, and Mo under varying groundwater geochemical conditions. Aquifer matrix materials from three distinct locations at the DOE UMTRA Project site in Rifle, CO, were used as the adsorbents under different pH conditions; these conditions stimulated geochemical environments under the tailings, near the tailings, and downgradient from the tailings. Grain size, total surface area, bulk and clay mineralogy, and petrography of the sediments were characterized. U and Mo yielded linear isotherms, while As had nonlinear ones. U and Mo were adsorbed strongly on sediments acidified to levels similar to tailings leachate. Changes in pH had much less effect on As adsorption. Mo was adsorbed very little at pH 7-7.3, U was weakly sorbed, and As was moderately sorbed. Velocities were estimated for metal transport at different pHs. Results show that the aquifer materials must be characterized to estimate metal transport velocities in aquifers and to develop groundwater restoration strategies for the UMTRA project.

  3. Factors influencing caesium-137 levels in moose (Alces alces) and small game in Northern Sweden

    International Nuclear Information System (INIS)

    In the third annual hunting season after the Chernobyl accident the concentration of Cs-137 in meat of northern Swedish moose was significantly higher than in the first one (1986). In September 1986 the mean Cs concentration was 500 Bq/kg in calves but in September 1988 it has risen 1300 Bq/kg. This increase was only temporary and a rapid decline occured after September and by December 1988 the concentration of Cs was the same as in late 1986. Adult moose showed the same increase during the hunt 1988 but to a lower magnitude. Typical food plants of moose such as bilberry (Vaccinum myrtillus) and birch (Betula pubescens) showed, contradictory to expected by the level in moose, a decline of concentration caesium from 1986 to 1988. A probable explanation to the dramatically increased concentration of Cs in moose is a change in diet selection during 1988. Small mammals such as voles and lemmings showed a variation in concentration of caesium-137 which was more dependent on other factors than on their body size. This emphasize the necessity to study diet selection by herbivores in detail in order to predict uptake and changes in environmental contaminants. (orig.)

  4. Hydroxyapatite supported caesium carbonate as a new recyclable solid base catalyst for the Knoevenagel condensation in water

    Directory of Open Access Journals (Sweden)

    Monika Gupta

    2009-11-01

    Full Text Available The Knoevenagel condensation between aromatic aldehydes and malononitrile, ethyl cyanoacetate or malonic acid with hydroxyapatite supported caesium carbonate in water is described. HAP–Cs2CO3 was found to be a highly active, stable and recyclable catalyst under the reaction conditions.

  5. Hydroxyapatite supported caesium carbonate as a new recyclable solid base catalyst for the Knoevenagel condensation in water

    OpenAIRE

    Monika Gupta; Rajive Gupta; Medha Anand

    2009-01-01

    The Knoevenagel condensation between aromatic aldehydes and malononitrile, ethyl cyanoacetate or malonic acid with hydroxyapatite supported caesium carbonate in water is described. HAP–Cs2CO3 was found to be a highly active, stable and recyclable catalyst under the reaction conditions.

  6. Effects of sorption behaviour on contaminant migration

    International Nuclear Information System (INIS)

    The effects of sorption behaviour on contaminant migration in groundwater systems are varied. Retardation of migration and dispersive effects can vary widely and contaminant concentration profiles can take a number of different shapes. This report examines the nature of some of these effects, especially those due to sorption behaviours that are dependent on the concentration of the contaminant in the groundwater. The effects are calculated using, in most cases, analytical solutions to the chemical equations imbedded in a simple reaction-cell or box-model transport algorithm. The hydrogeological parameters are held constant, and radioactive decay and hydrodynamic dispersion are excluded. A general discussion of the role of sorption equations in transport modelling is followed by presentation of migration results for a number of models of sorption behaviour varying from linear isotherms, Langmuir, Freundlich and ion-exchange isotherms, to precipitation reactions and multiple-site sorption reactions. The results are compared and general conclusions are drawn about the various migration behaviours calculated. The conclusions are that equilibrium sorption of trace contaminants can be modelled with linear isotherms (constant distribution coefficients or constant retardation factors) but the evaluation and extrapolation of the distribution coefficient are not easy. Nonlinear isotherms lead to unsymmetrical migration fronts. A comparison of Freundlich and linear isotherms is made. Sorption/desorption kinetic factors can be significant on the time scale of laboratory experiments and can cause large dispersive effects. Slow but important reactions can be missed altogether. Precipitation or mineralization behaviour cannot be modelled with constant distribution coefficients. Also, mineralization reactions can be kinetically slow even on the geological time scale. 89 refs

  7. Isothermal Shock Wave in Magnetogasdynamics

    Directory of Open Access Journals (Sweden)

    B. G. Verma

    1983-01-01

    Full Text Available The problem of propagation of a plane isothermal discontinuity (shock wave in a homogeneous semi-infinite body of a perfect gas, in the presence of amagnetic field have been solved. It has been shown that under certain definiteconditions, the density p at the wave front may be arbitrarily high for a singlecompression pulse. A certain class of solutions of the present problem for a nonhomogeneous semi-infinite body have been derived. Such solutions are expected to be of great importance in compression problems of plasma.

  8. Isothermal Shock Wave in Magnetogasdynamics

    OpenAIRE

    B. G. Verma; J. P. Vishwakarma; Vishnu Sharan

    1983-01-01

    The problem of propagation of a plane isothermal discontinuity (shock) wave in a homogeneous semi-infinite body of a perfect gas, in the presence of amagnetic field have been solved. It has been shown that under certain definiteconditions, the density p at the wave front may be arbitrarily high for a singlecompression pulse. A certain class of solutions of the present problem for a nonhomogeneous semi-infinite body have been derived. Such solutions are expected to be of great importance in co...

  9. Biosorption isotherm for uranium recovery

    International Nuclear Information System (INIS)

    An analysis of the biological sorption of uranium on mycelia of Penicillium C-1 is provided. From an isotherm test, a rough estimate of the biomass, required for removal of uranium to a certain level can be attained. The process presents a new approach towards water pollution control and resource recovery. The biosorption method may find its greatest application in solutions of low uranium concentration (100 ppM to 300 ppM) such as in waste mine water or very lean leach solutions

  10. Specific features of 137Cs migration and accumulation in chernozem soils of forest ecosystems in the zone contaminated due to the Chornobyl accident

    International Nuclear Information System (INIS)

    A number of factors influencing 137Cs fate and biological availability in chernozem soils under the forest vegetation were assessed for various climatic zones. The migration rates of 137Cs in the profile of chernozem soils were shown to depend primary on forest litter composition and structure. In the absence of forest litter the soil mineralogical composition and humus content become the most influential factors of caesium mobility

  11. Caesium-137 as Indicator of Present Mass-Movement and Erosion Processes

    Science.gov (United States)

    Supper, R.; Baron, I.; Winkler, E.; Motschka, K.; Jaritz, W.; Moser, G.; Carman, M.

    2012-04-01

    After the Chernobyl atomic accident in April 1986, notable parts of Eastern, Northern and Central Europe were contaminated by Caesium-137 (137Cs). This radioactive isotope with 30.17 years half-life is completely of anthropogenic origin. After the accident it was transported through the atmosphere for long distances and contaminated the soil surface variably in the vast areas. Although much of the 137Cs content has already decayed, notable amounts can still be detected. The Department of Geophysics of the Geological Survey of Austria conducted in 2009 an airborne multi-sensor geophysical survey over three prominent landslides in Austria and Slovenia as a test study for the application of airborne geophysics for landslide investigations. Besides elelectromagnetic (subsurface resistivity) and passive microwave (soil moisture) measurements, a gamma ray survey was done; natural radioactive isotopes such as Potassium, Thorium, and Uranium were mapped. This paper deals only with the Caesium-137 distribution. The Gschliefgraben test site (N Austria) is a complex of active and dormant earthflows, landslides and rockfalls in a 4 km long valley at the foot of Northern Calcareous Alps within Ultrahelvetic and Rhenodanubian flysch rocks. The last major reactivation occurred in 2007 and 2008. Also the Sibratsgfäll test site (W Austria) is a complex of shallow and deep-seated landslides and earthflows in sedimentary rocks of the Helvetic Zone, Liebenstein Nappe, Feuerstätte Zone and the Rhenodanubian Flysch. Here the major recent reactivation occurred in May 1999 affecting the villages of Sibratsgfäll and Rindberg. The Stoze landslide (NW Slovenia) occurred in November 2000 and is situated in dolomitic to clayey and marly Upper Triassic rocks, in Quaternary glacial moraine sediments and slope debris. The Caesium-137 maps were compared to landslide inventory maps, airborne laser-scan DTMs and up-to-date orthophotos. In all of the test sites, the 137Cs minima correlated well

  12. Room temperature isotherms for Mo and Ni

    International Nuclear Information System (INIS)

    Isotherms at room temperature for Mo and Ni are proposed. They are of three types: BIRCH, KEANE and BORN-MIE. The adjustable constants appearing in these isotherms have been determined from experimental quantities at zero pressure. An evaluation of the limit of (δBT/δP)T as P #-> # ∞, where BT is the isothermal bulk modulus, has been also used. These three isotherms obtained for Mo and Ni are compared with isotherms derived from shock-wave data according to the PRIETO's model. There is a good agreement between these and these derived from shock-wave data. The three isotherms proposed for Mo and Ni can be considered as valid until pressures of several BTo, where BTo is the bulk modulus BT at P = o

  13. Monitoring of caesium-137 in food plants and muscle from moose, red deer and wild reindeer in 2010

    International Nuclear Information System (INIS)

    The monitoring of Cs-137 fall-out from the Chernobyl accident in 1986, started the same year. Several plants and wild reindeer in natural ecosystems in Nord-Rondane have been followed annually ever since. Four more wild reindeer ranges were included in 2001: Setesdal-Ryfylkeheiene, Hardangervidda, Nord-Ottadalen, Snoehetta and Nord-Rondane. From 2007 Forollhogna was also included. On fixed plots in Nord-Rondane and Snoehetta some of the reindeer forage plants, including both higher plants and fruticose lichens, have been sampled and analyzed annually since 1986. This was also done in 2010. In addition plants and lichens were sampled at five locations along an altitudinal gradient at Soendre Knutshoe, and at 7-8 locations along an east-west gradient from Kollaflata to Skarhoe in the Jora valley continuing along the Aursjoe to Torbudalen. All these locations were sampled annually between 1987-1990, but they have not been sampled since. In 2010 samples from red deer and moose was also collected from eight different regions located within the following counties: Oppland, Telemark, Vest-Agder, Rogaland, Sogn and Fjordane, Nord-Troendelag, Nordland and Troms. Red deer were sampled in four regions and moose in six. Both species were sampled in Oppland. In 2010 76, 49 and 61 samples were collected from wild reindeer, red deer and moose respectively. All measures of caesium levels were performed on dried samples. For the 596 samples of plants and lichen the results refer to caesium-levels in dried samples. For the meat samples, results refer to caesium-137 levels in raw meat. Due to large variation in measured levels of caesium within species and sampling area, we give median values instead of mean values.The highest caesium levels in wild reindeer were found in Snoehetta (1010 Bq/kg) and Nord-Rondane (2686 Bq/kg). The levels found in the other areas were considerably lower. The highest caesium levels in both red deer (Sel, 677 Bq/kg) and moose (Vaaga, 365 Bq/kg) were found

  14. Modeling of Experimental Adsorption Isotherm Data

    OpenAIRE

    Xunjun Chen

    2015-01-01

    Adsorption is considered to be one of the most effective technologies widely used in global environmental protection areas. Modeling of experimental adsorption isotherm data is an essential way for predicting the mechanisms of adsorption, which will lead to an improvement in the area of adsorption science. In this paper, we employed three isotherm models, namely: Langmuir, Freundlich, and Dubinin-Radushkevich to correlate four sets of experimental adsorption isotherm data, which were obtained...

  15. Caesium carbonate as a highly efficient catalyst for the synthesis of macrocyclicdiamides

    Directory of Open Access Journals (Sweden)

    Esmael Rostami

    2014-07-01

    Full Text Available In this research work, we report the synthesis of macrocyclicdiamides from the reaction of diesters and aliphatic diamines in the presence of caesium carbonate. It has been demonstrated that among the carbonate of alkali metals (Li2CO3, Na2CO3, K2CO3 and CS2CO3, CS2CO3 appears to be the best catalyst for macrocyclization. Diesters with different substitution patterns on the aromatic ring reacted smoothly with diamines under optimal conditions, affording the corresponding macrocycles in high yields. Introducing a rigid group (e.g., sulfone on the substrate led to somewhat decreased yield. Various substrates proved to be suitable for this macrocyclization reaction, especially, the flexible ones.

  16. Synthetic crystalline calcium silicate hydrate (I): cation exchange and caesium selectivity

    International Nuclear Information System (INIS)

    Solid crystalline calcium silicate hydrate (I) synthesized from equimolar amounts of Ca and Si under hydrothermal conditions at 120 oC shows cation exchange properties towards divalent metal cations such as Ni, Cu, Cd, or Hg. It also exhibits caesium selectivity in the presence of Na+. The exchange capacity and selectivity of the solid can be increased by 10 and 28 %, respectively, upon substitution of 0.01 mol of the Ca2+ in its structure by Na+. The ability of metal cation uptake by the solid was found to obey the order Ni2+ > Hg2+ > Cu2+ > Cd2+. The different affinities of calcium silicate hydrate (I) towards these ions can be used for their separation from solutions and also in nuclear waste treatment. The mechanism of the exchange reaction is discussed. (author)

  17. Enhanced Raman sideband cooling of caesium atoms in a vapour-loaded magneto-optical trap

    CERN Document Server

    Li, Y; Feng, G; Nute, J; Piano, S; Hackermuller, L; Ma, J; Xiao, L; Jia, S

    2015-01-01

    We report enhanced three-dimensional degenerated Raman sideband cooling (3D DRSC) of caesium (Cs) atoms in a standard single-cell vapour-loading magneto-optical trap. Our improved scheme involves using a separate repumping laser and optimized lattice detuning. We load $1.5 \\times 10^7$ atoms into the Raman lattice with a detuning of -15.5 GHz (to the ground F = 3 state). Enhanced 3D DRSC is used to cool them from 60 $\\mu$K to 1.7 $\\mu$K within 12 ms and the number of obtained atoms is about $1.2 \\times 10^7$. A theoretical model is proposed to simulate the measured number of trapped atoms. The result shows good agreement with the experimental data. The technique paves the way for loading a large number of ultracold Cs atoms into a crossed dipole trap and efficient evaporative cooling in a single-cell system.

  18. Experimental observation of pump-probe spectra of caesium D2 line with a vapour cell

    Institute of Scientific and Technical Information of China (English)

    Wang Yan-Hua; Yang Hai-Jing; Zhang Tian-Cai; Wang Jun-Min

    2005-01-01

    Pump-probe spectra of caesium D2 line are experimentally investigated in a Cs atomic vapour cell with copropagating orthogonal linearly-polarized pump and probe laser beams. Absorption-reduction dips duo to electromagnetically induced transparency (EIT) in multi-A-type Zeeman sublevels of 6 S1/2 F=3-6 P3/2 F'=2 hyperfine transition and absorption-enhanced peaks due to electromagnetically induced absorption (EIA) in 6 S1/2 F=4-6 P3/2 F'=5 hyperfine transition are demonstrated. With detuned pump beam abnormal sign-reversed signals inside the EIT dip and the EIA peak are clearly observed.

  19. Observation of four-wave mixing in caesium atoms using a noncycling transition

    Institute of Scientific and Technical Information of China (English)

    Wang Li-Rong; Ma Jie; Zhao Jian-Ming; Xiao Lian-Tuan; Jia Suo-Tang

    2006-01-01

    In this paper the generation of four-wave mixing (FWM) signal using a noncycling transition of caesium atoms is investigated when the pumping laser is locked to the transition 6S1/2F = 4 → 6P3/2F' = 4, and meanwhile the probe frequency is scanned across the 6S1/2F = 4 → 6P3/2 transition. The efficiency of the four-wave mixing signal as a function of the intensity of the pumping beams and the detuning of the pumping beams is also studied. In order to increase the detection efficiency, a repumping laser which is resonant with 6S1/2F = 3 → 6P3/2F' = 4 transition is used. A theoretical model is also introduced, and the theoretical results are in qualitative agreement with experimental ones.

  20. Caesium Radionuclide Uptake from Wet Soil to Kangkung Plant (Ipomoea sp)

    International Nuclear Information System (INIS)

    Caesium radionuclide transfer from soil to kangkung plant (Ipomoea sp) generally consumed by people had been examined to obtain transfer factor value for internal radiation dose assessment via soil-plant-human pathway. The kangkung plants were cultivated on watered soil medium containing 134Cs with concentration of about 80 Bq/g, and the 134Cs uptake by plants, i.e root, stem, and leaves, were measured using gamma spectrometer. The 134Cs plant uptake was expressed as transfer factor, i.e. ratio of plant 134Cs concentration to 134Cs concentration on soil medium. From this research it was obtained transfer factor value of 134C from soil to plant is 0.07, and the transfer factor for root, stem, and leaves are 0.34 ; 0.05 ; 0,03 respectively, after 45 days cultivation. The transfer factor values are less than one, indicate that kangkung plant do not accumulate Cs radionuclide from soil. (author)

  1. Five years hospital experience with the Amersham caesium 137 manual afterloading system

    Energy Technology Data Exchange (ETDEWEB)

    Bateman, T.J.; Davy, T.J.; Skeggs, D.B.L. (Royal Free Hospital, London (UK))

    1983-06-01

    The Amersham caesium 137 manual afterloading system for treatment of cancer of the uterine cervix and endometrium has been in use at the Royal Free Hospital for more than five years. The system uses permanently loaded flexible source pencils in combination with standard packs of disposable plastic applicators. Both sources and applicators have proved trouble-free in use. The sources are transported in special containers designed and built at the Royal Free Hospital and are inserted and removed on the ward by nursing staff. A set of sources is used in theatre for rectal and bladder dose measurements when the applicators are inserted. Staff radiation doses are low. The system is mainly used to produce pear-shaped dose distributions similar to those of the Manchester system, but simple cylindrical distributions are possible using symmetrically loaded source pencils.

  2. Medical migration.

    Science.gov (United States)

    Loefler, I J

    2001-10-01

    The issue of professional migration, however emotional it may have become, ought not to be regarded in moralizing terms. The history of western medicine is the history of migrating physicians. A doctor who moves from a locality to another to take up a new assignment there cannot be said to have "abandoned his patients". This emotional bond has become the victim of specialization and of depersonalization of medical services and not of medical migration, brain drain or otherwise. The primary reason for medical migration is not financial; the desire to migrate usually begins with the desire to learn. Professionals crave in the first line for professional satisfaction. The migration of medical manpower cannot be stopped with administrative measures and will not be stopped by exhortations and appeals, moralization and condemnations. Brain drain is a global phenomenon and has always been so. A country which loses its professionals, its doctors, should examine the social relationships within the profession and should investigate whether the opportunities for deriving professional satisfaction from everyday work exist or whether these have been thwarted by the hierarchy, conservatism, cronyism and the general lack of comprehension of what good medical care is about. PMID:11593497

  3. Migration chemistry

    International Nuclear Information System (INIS)

    Migration chemistry, the influence of chemical -, biochemical - and physico-chemical reactions on the migration behaviour of pollutants in the environment, is an interplay between the actual natur of the pollutant and the characteristics of the environment, such as pH, redox conditions and organic matter content. The wide selection of possible pollutants in combination with varying geological media, as well as the operation of different chemical -, biochemical - and physico-chemical reactions compleactes the prediction of the influence of these processes on the mobility of pollutants. The report summarizes a wide range of potential pollutants in the terrestrial environment as well as a variety of chemical -, biochemical - and physico-chemical reactions, which can be expected to influence the migration behaviour, comprising diffusion, dispersion, convection, sorption/desorption, precipitation/dissolution, transformations/degradations, biochemical reactions and complex formation. The latter comprises the complexation of metal ions as well as non-polar organics to naturally occurring organic macromolecules. The influence of the single types of processes on the migration process is elucidated based on theoretical studies. The influence of chemical -, biochemical - and physico-chemical reactions on the migration behaviour is unambiguous, as the processes apparently control the transport of pollutants in the terrestrial environment. As the simple, conventional KD concept breaks down, it is suggested that the migration process should be described in terms of the alternative concepts chemical dispersion, average-elution-time and effective retention. (AB) (134 refs.)

  4. Evaluation of sorption data with a view to nonlinear sorption models of nuclide migration in overlying rock strata; Auswertung von Sorptionsdaten hinsichtlich nichtlinearer Sorptionsmodelle fuer die Nuklidausbreitung im Deckgebirge

    Energy Technology Data Exchange (ETDEWEB)

    Noseck, U.

    1996-09-01

    So far, only the linear sorption model and the K{sub d} concept were used for modelling radionuclide migration in overlying rock strata. However, for some of the safety-relevant elements (Ni, U, Pb, Cs), sorption experiments on overlying rock sediments also suggested that the sorption coefficients may be influenced by the element concentrations. This nonlinear sorption behaviour may affect the results of long-term safety analyses for some nuclides. For this reason, both the K{sub d} values as well as parameters for the nonlinear sorption isotherms of Freundlich and Langmuir were determined from the available experimental data for the four above-mentioned elements. The parameters were determined exemplarily for five different aquiferous strata of the Gorleben overlying rock. In order to find out how the results of migration calculations will be influenced by the description of retention by nonlinear sorption isotherms as compared with the K{sub d} concept, comparative calculations were carried out for a complete ultimate storage system, assuming the sorption characteristics obtained for each sediment layer as retention characteristics of the overlying rock. The calculations were carried out using the one-dimensional transport program CHET2. (orig./DG) [Deutsch] In Modellrechnungen zur Radionuklidausbreitung im Deckgebirge wurde bisher ausschliesslich der lineare Sorptionsansatz und damit das K{sub d}-Konzept verwendet. Fuer einen Teil der sicherheitsrelevanten Elemente, wie etwa Nickel, Uran, Blei und Caesium, wurde in Sorptionsexperimenten an Deckgebirgssedimenten eine Abhaengigkeit der Sorptionskoeffizienten von der Elementkonzentration festgestellt. Ein solches nichtlineares Sorptionsverhalten kann gegenueber der linearen Sorption fuer einzelne Nuklide die Ergebnisse von Langzeitsicherheitsanalysen beeinflussen. Aus den vorliegenden experimentellen Daten wurden deshalb fuer die vier genannten Elemente zum einen K{sub d}-Werte, zum anderen Parameter fuer die

  5. [Internal migration].

    Science.gov (United States)

    Borisovna, L

    1991-06-01

    Very few studies have been conducted that truly permit explanation of internal migration and it repercussions on social and economic structure. It is clear however that a profound knowledge of the determinants and consequences of internal migration will be required as a basis for economic policy decisions that advance the goal of improving the level of living of the population. the basic supposition of most studies of the relationship of population and development is that socioeconomic development conditions demographic dynamics. The process of development in Mexico, which can be characterized by great heterogeneity, consequently produces great regional disparities. At the national level various studies have estimated the volume of internal migration in Mexico, but they have usually been limited to interstate migration because the main source of data, the census, is classified by states. But given the great heterogeneity within states in all the elements related to internal migration, it is clear that studies of internal migration within states are also needed. Such studies are almost nonexistent because of their technical difficulty. National level studies show that interstate migration increased significantly between 1940-80. The proportion of Mexicans living outside their states of birth increased by 558% in those years, compared to the 342% increase in the total Mexican population. Although Puebla has a high rate of increase, migration has kept it below Mexico's national growth rate. Migration between Puebla and other states and within Puebla has led to an increasing unevenness of spatial distribution. Between 1970-80, 57 of Puebla's municipios had growth rates above the state average of 2.8%/year, 6 had growth rates equal to the average, and 129 had growth rates that were below the average but not negative. 25 states with negative growth rates that were considered strongly expulsive. In 1980, 51.7% of the population was concentrated in the 57 municipios

  6. Uptake and retention of radio-caesium in earthworms cultured in soil contaminated by the Fukushima nuclear power plant accident.

    OpenAIRE

    Fujiwara, K.; T. Takahashi; P. Nguyen; Kubota, Y.; Gamou, S; Sakurai, S; Takahashi, S

    2015-01-01

    To understand the effects of radionuclides on non-human biota and the environment, it is essential to study the intake and metabolism of radio-isotopes in earthworms which are among the most important soil organisms, and Eisenia fetida, which were used in this study, are known to be sufficiently sensitive to chemicals and representative of common earthworms. In this study, we assessed the concentration ratios, uptake and retention, absorbed dose rate, and distribution of radio-caesium in eart...

  7. Isothermal air ingress validation experiments

    International Nuclear Information System (INIS)

    Idaho National Laboratory carried out air ingress experiments as part of validating computational fluid dynamics (CFD) calculations. An isothermal test loop was designed and set to understand the stratified-flow phenomenon, which is important as the initial air flow into the lower plenum of the very high temperature gas cooled reactor (VHTR) when a large break loss-of-coolant accident occurs. The unique flow characteristics were focused on the VHTR air-ingress accident, in particular, the flow visualization of the stratified flow in the inlet pipe to the vessel lower plenum of the General Atomic's Gas Turbine-Modular Helium Reactor (GT-MHR). Brine and sucrose were used as heavy fluids, and water was used to represent a light fluid, which mimics a counter current flow due to the density difference between the stimulant fluids. The density ratios were changed between 0.87 and 0.98. This experiment clearly showed that a stratified flow between simulant fluids was established even for very small density differences. The CFD calculations were compared with experimental data. A grid sensitivity study on CFD models was also performed using the Richardson extrapolation and the grid convergence index method for the numerical accuracy of CFD calculations . As a result, the calculated current speed showed very good agreement with the experimental data, indicating that the current CFD methods are suitable for predicting density gradient stratified flow phenomena in the air-ingress accident. (author)

  8. ISOTHERMAL AIR INGRESS VALIDATION EXPERIMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Chang H Oh; Eung S Kim

    2011-09-01

    Idaho National Laboratory carried out air ingress experiments as part of validating computational fluid dynamics (CFD) calculations. An isothermal test loop was designed and set to understand the stratified-flow phenomenon, which is important as the initial air flow into the lower plenum of the very high temperature gas cooled reactor (VHTR) when a large break loss-of-coolant accident occurs. The unique flow characteristics were focused on the VHTR air-ingress accident, in particular, the flow visualization of the stratified flow in the inlet pipe to the vessel lower plenum of the General Atomic’s Gas Turbine-Modular Helium Reactor (GT-MHR). Brine and sucrose were used as heavy fluids, and water was used to represent a light fluid, which mimics a counter current flow due to the density difference between the stimulant fluids. The density ratios were changed between 0.87 and 0.98. This experiment clearly showed that a stratified flow between simulant fluids was established even for very small density differences. The CFD calculations were compared with experimental data. A grid sensitivity study on CFD models was also performed using the Richardson extrapolation and the grid convergence index method for the numerical accuracy of CFD calculations . As a result, the calculated current speed showed very good agreement with the experimental data, indicating that the current CFD methods are suitable for predicting density gradient stratified flow phenomena in the air-ingress accident.

  9. The non-isothermal rheology of low viscosity magmas.

    Science.gov (United States)

    Kolzenburg, Stephan; Giordano, Daniele; Dingwell, Donald B.

    2016-04-01

    Accurate prediction of the run-out distance of lava flows, as well as the understanding of magma migration in shallow dyke systems is hampered by an incomplete understanding of the transient, sub-liquidus rheology of crystallizing melts. This sets significant limits to physical property based modelling of lava flow (especially flow width, length and advancement rate) and magma migration behaviour and the resulting accuracy of volcanic hazard assessment The importance of the dynamic rheology of a lava / magma on its emplacement style becomes especially apparent in towards later stages of flow and dyke emplacement, where the melt builds increasing resistance to flow, entering rheologic regimes that determine the halting of lava flows and sealing of dykes. Thermal gradients between the interior of a melt body and the contact with air or the substratum govern these rheologic transitions that give origin to flow directing or impeding features like levees, tubes and chilled margins. Besides the critical importance of non-isothermal and sub-liquidus processes for the understanding of natural systems, accurate rheologic data at these conditions are scarce and studies capturing the transient rheological evolution of lavas at conditions encountered during emplacement virtually absent. We describe the rheologic evolution of a series of natural, re-melted lava samples during transient and non-equilibrium crystallization conditions characteristic of lava flows and shallow magmatic systems in nature. The sample suite spans from foidites to basalts; the dominant compositions producing low viscosity lava flows. Our data show that all melts undergo one or more change zones in effective viscosity when subjected to sub liquidus temperatures. The apparent viscosity of the liquid-crystal suspension increases drastically from the theoretical temperature-viscosity relationship of a pure liquid once cooled below the liquidus temperature. We find that: 1) Both cooling rate and shear rate

  10. Adsorption from Experimental Isotherms of Supercritical Gases

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A mathematical method was proposed for the determination of absolute adsorption from experimental isotherms. The method is based on the numerical equality of the absolute and the excess adsorption when either the gas phase density or the amount adsorbed is not quite considerable. The initial part of the experimental isotherms, which represents the absolute adsorption, became linear with some mathematical manipulations. The linear isotherms were reliably formulated. As consequence, either the volume or the density of the supercritical adsorbate could be determined by a non-empirical way. This method was illustrated by the adsorption data of supercritical hydrogen and methane on a superactivated carbon in large ranges of temperature and pressure.

  11. Applicability of Different Isothermal EOS at Nanomaterials

    OpenAIRE

    Deepika P. Joshi; Anjali Senger

    2013-01-01

    The present study explains the behaviour of nanomaterials such as AlN, CdSe, Ge, WC, and Ni- and Fe-filled-MWCNTs under high pressure. Among the number of isothermal EOSs available, we prefer only two parameter-based isothermal equations (i.e., Murnaghan equation, usual Tait's equation, Suzuki equation and Shanker equation). The present work shows the theoretical study of thermo-elastic properties especially relative compression (V/V0), isothermal bulk modulus (KP/K0), and compressibility (αP...

  12. Monarch Migration.

    Science.gov (United States)

    Williamson, Brad; Taylor, Orley

    1996-01-01

    Describes the Monarch Watch program that tracks the migration of the monarch butterfly. Presents activities that introduce students to research and international collaboration between students and researchers. Familiarizes students with monarchs, stimulates their interest, and helps them generate questions that can lead to good research projects.…

  13. Vortex migration in protoplanetary disks

    CERN Document Server

    Paardekooper, S -J; Papaloizou, J C B

    2010-01-01

    We consider the radial migration of vortices in two-dimensional isothermal gaseous disks. We find that a vortex core, orbiting at the local gas velocity, induces velocity perturbations that propagate away from the vortex as density waves. The resulting spiral wave pattern is reminiscent of an embedded planet. There are two main causes for asymmetries in these wakes: geometrical effects tend to favor the outer wave, while a radial vortensity gradient leads to an asymmetric vortex core, which favors the wave at the side that has the lowest density. In the case of asymmetric waves, which we always find except for a disk of constant pressure, there is a net exchange of angular momentum between the vortex and the surrounding disk, which leads to orbital migration of the vortex. Numerical hydrodynamical simulations show that this migration can be very rapid, on a time scale of a few thousand orbits, for vortices with a size comparable to the scale height of the disk. We discuss the possible effects of vortex migrat...

  14. Adsorption Isotherms and Surface Reaction Kinetics

    Science.gov (United States)

    Lobo, L. S.; Bernardo, C. A.

    1974-01-01

    Explains an error that occurs in calculating the conditions for a maximum value of a rate expression for a bimolecular reaction. The rate expression is derived using the Langmuir adsorption isotherm to relate gas pressures and corresponding surface coverages. (GS)

  15. Isothermal calorimeter for reactor radiation dosimetry

    International Nuclear Information System (INIS)

    An isothermal calorimeter with thermistors for measuring absorbed dose rates from 104-5-6.105 rad/h in reactor experimental holes has been designed. A kinetics method for determining the equilibrium temperature difference has been developed, and its application in isothermal calorimetry proved. The expected accuracy in measurements within ± 2-5% has been proved by measurements carried out in the reactor. Some data obtained by measurements in the reactor RA are presented (author)

  16. [The importance of gamma irradiations with caesium-137 for Hyalomma anatolicum anatolicum (Metastigmata, Ixodidae) control].

    Science.gov (United States)

    Karaer, Zafer; Kar, Sirri; Düzgün, Ali; Güven, Esin; Pekmezci, Zafer; Emre, Zişan

    2006-01-01

    In this study, male ticks belonging to the Hyalomma anatolicum anatolicum species were subjected to gamma radiation doses of 5, 10, 15, 20 and 50 Gy, emitted by a gamma-ray source of Caesium 137. In females that fed with these male ticks, proportional to the increase in radiation dose, the period of feeding was found to shorten. A decrease was demonstrated in the number of engorged female ticks, engorgement weights, number of laying ticks and number of eggs. The hatching period of larvae from eggs was found to increase despite the decrease in the number of hatched larvae. Moreover no larvae were observed to hatch from any of the eggs of female ticks treated with a radiation dose of 50 Gy. Similarly, proportional to the applied dose of radiation, rates of viability and activity were observed to decrease in male ticks. In conclusion, taking into consideration the feeding periods and fertility rates of female ticks as indicators of male activity, this study has demonstrated that in combating with H. anatolicum anatolicum, radiation may be successful and a radiation dose of 10 Gy is most favorable.

  17. Radiative heat transfer in plasma of pulsed high pressure caesium discharge

    Science.gov (United States)

    Lapshin, V. F.

    2016-01-01

    Two-temperature many component gas dynamic model is used for the analysis of features of radiative heat transfer in pulsed high pressure caesium discharge plasma. It is shown that at a sufficiently high pressure the radial optical thickness of arc column is close to unit (τR (λ) ∼ 1) in most part of spectrum. In this case radiative heat transfer has not local character. In these conditions the photons which are emitted in any point of plasma volume are absorbed in other point remote from an emission point on considerable distance. As a result, the most part of the electric energy put in the discharge mainly near its axis is almost instantly redistributed on all volume of discharge column. In such discharge radial profiles of temperature are smooth. In case of low pressure, when discharge plasma is optically transparent for own radiation in the most part of a spectrum (τR(λ) << 1), the emission of radiation without reabsorption takes place. Radiative heat transfer in plasma has local character and profiles of temperature have considerable gradient.

  18. A dynamic model of caesium transport in lakes and their catchments

    International Nuclear Information System (INIS)

    A mathematical model has been developed to predict radiocaesium concentrations over time within individual compartments of the lake and its catchment. The lake has been divided into five compartments; catchment, lake water (epilimnion and hypolimnion during stratification), lake sediment and fish. Radiocaesium enters the lake via contaminated rainfall and catchment runoff. A proportion of this radiocaesium absorbs onto suspended solids in the lake. This proportion is represented by a distribution coefficient. Sedimentation of the suspended solids occurs at a rate defined by the areal removal coefficient and results in increased caesium concentrations in the sediment. The ingestion of radiocaesium by either water column or benthic feeding fish is described by transfer functions. The model has been tested against data collected from Esthwaite water and Windermere shortly after the Chernobyl reactor accident from May 1986 to December 1987. The model simulates observed radiocaesium concentrations in Esthwaite lake water and sediment and also in lake water, sediment and fish in Windermere. The model could form the basis of a valuable management tool for the water industry should a major airborne pollution event occur again. (author)

  19. ON THE ISOTHERMALITY OF SOLAR PLASMAS

    International Nuclear Information System (INIS)

    Recent measurements have shown that the quiet unstructured solar corona observed at the solar limb is close to isothermal, at a temperature that does not appear to change over wide areas or with time. Some individual active region loop structures have also been found to be nearly isothermal both along their axis and across their cross section. Even a complex active region observed at the solar limb has been found to be composed of three distinct isothermal plasmas. If confirmed, these results would pose formidable challenges to the current theoretical understanding of the thermal structure and heating of the solar corona. For example, no current theoretical model can explain the excess densities and lifetimes of many observed loops if the loops are in fact isothermal. All of these measurements are based on the so-called emission measure (EM) diagnostic technique that is applied to a set of optically thin lines under the assumption of isothermal plasma. It provides simultaneous measurement of both the temperature and EM. In this work, we develop a new method to quantify the uncertainties in the technique and to rigorously assess its ability to discriminate between isothermal and multithermal plasmas. We define a formal measure of the uncertainty in the EM diagnostic technique that can easily be applied to real data. We here apply it to synthetic data based on a variety of assumed plasma thermal distributions and develop a method to quantitatively assess the degree of multithermality of a plasma.

  20. Unified water isotherms for clayey porous materials

    Science.gov (United States)

    Revil, A.; Lu, N.

    2013-09-01

    We provide a unified model for the soil-water retention function, including the effect of bound and capillary waters for all types of soils, including clayey media. The model combines a CEC-normalized isotherm describing the sorption of the bound water (and the filling of the trapped porosity) and the van Genuchten model to describe the capillary water sorption retention but ignore capillary condensation. For the CEC-normalized isotherm, we tested both the BET and Freundlich isotherms, and we found that the Freundlich is more suitable than the BET isotherm in fitting the data. It is also easier to combine the Freundlich isotherm with the van Genuchten model. The new model accounts for (1) the different types of clay minerals, (2) the different types of ions sorbed in the Stern layer and on the basal planes of 2:1 clays, and (3) the pore size distribution. The model is validated with different data sets, including mixtures of kaolinite and bentonite. The model parameters include two exponents (the pore size exponent of the van Genuchten model and the exponent of the Freundlich isotherm), the capillary entry pressure, and two critical water contents. The first critical water content is the water content at saturation (porosity), and the second is the maximum water content associated with adsorption forces, including the trapped nonbound water.

  1. Gideon's Migration

    OpenAIRE

    Eagly, Ingrid

    2013-01-01

    For the past fifty years, immigration law has resisted integration of Gideon v.Wainwright’s legacy of appointed counsel for the poor. Today, however, this resistance has given way to Gideon’s migration. At the level of everyday practice, criminal defense attorneys appointed pursuant to Gideon now advise clients on the immigration consequences of convictions, negotiate “immigration safe” plea bargains, defend clients charged with immigration crimes, and, in some model programs, even represent ...

  2. In-vivo estimates for the uptake of caesium-137 by cattle grazing contaminated pasture around the Esk and Irt estuaries, Cumbria, U.K

    International Nuclear Information System (INIS)

    Sea water contaminated with diluted radioactive effluent from the Windscale nuclear complex in Cumbria periodically floods low-lying grazing pasture around the estuaries of the rivers Esk, Irt and Mite near Ravenglass. During 1979, an experiment was carried out to measure the transfer of caesium-137 from grass to muscle in cows grazing these pastures. Grass samples were taken and in vivo external gamma-ray measurements were made on cattle. A very low transfer coefficient was found, less than 9 x 10-4 days kg-1 with a best estimate of 4 x 10-4 days kg-1, compared with a more usual value of around 3 x 10-2 days kg-1. The low transfer seems to occur because the bulk of the caesium-137 on the grass is bound to resuspended estuarine surface sediment deposited during flooding. In this form, the caesium-137 is only poorly adsorbed across the gut of the grazing cattle. (orig.)

  3. In-vivo estimates for the uptake of caesium-137 by cattle grazing contaminated pasture around the ESK and IRT estuaries, Cumbria, U.K.

    Science.gov (United States)

    Sumerling, T J

    1981-12-01

    Sea water contaminated with diluted radioactive effluent from the Windscale nuclear complex in Cumbria periodically floods low-lying grazing pasture around the estuaries of the rivers Esk, Irt and Mite near Ravenglass. During 1979, an experiment was carried out to measure the transfer of caesium-137 from grass to muscle in cows grazing these pastures. Grass samples were taken in a vivo external gamma-ray measurements were made on cattle. A very low transfer coefficient was found, less than 9 X 10-4 days kg-1 with a best estimate of 4 X 10-4 days kg-1, compared with a more usual value of around 3 X 10-2 days kg-1. The low transfer seems to occur because the bulk of the caesium-137 on the grass is bound to resuspended estuarine surface sediment deposited during flooding. In this form, the caesium-137 is only poorly absorbed across the gut of the grazing cattle. PMID:7336201

  4. The influence of caesium-137 distribution in Poland's north-eastern ecosystem on effective dose 10 years after the Chernobyl disaster

    International Nuclear Information System (INIS)

    A comparison is presented of particular methods of exposure in the first year after the Chernobyl disaster and ten years later. This comparison shows that the population exposure due to the presence of radiocaesium in the environment results from the presence of caesium contained in the soil, which provides 68% of the dose (as compared to 32% in 1987) while the influence of diet has been reduced to 32% (from 68%). The exposure from caesium-137 contained in the air has dropped from 14% to 0. The effective dose from caesium has been 50 times smaller than that from environmental sources of the natural radiation estimated for the region under study to be 1.61 mSv.y-1. (author)

  5. Setting up the drying regimes based on the theory of moisture migration during drying

    Science.gov (United States)

    Vasić, M.; Radojević, Z.

    2016-08-01

    Drying is energy intensive process which has important effect on the quality of the clay tiles that are dried commercially. Chamber and tunnel dryers are constantly improving. Better technical equipment and operational strategies have lead to higher quality of the dried clay products. The moisture migration during isothermal drying process can be visually traced on the curve that represents the relationship between variable effective moisture diffusivity (MR) with time (t). Proposed non isothermal drying regimes were consisted from several isothermal segments. For the first time, the choice of isothermal segments specification and its duration was not specified by experience or by trial-and-error method. It was detected from the isothermal curves Deff - MR in accordance with the theory of moisture migration during drying. Proposed drying regimes were tested. Clay roofing tiles were dried without cracks. Dried clay roofing tiles has satisfied all requirements defined in EN 1304 norm related to the shape regularity and mechanical properties.

  6. A preference for migration

    OpenAIRE

    Stark, Oded

    2007-01-01

    At least to some extent migration behavior is the outcome of a preference for migration. The pattern of migration as an outcome of a preference for migration depends on two key factors: imitation technology and migration feasibility. We show that these factors jointly determine the outcome of a preference for migration and we provide examples that illustrate how the prevalence and transmission of a migration-forming preference yield distinct migration patterns. In particular, the imitation of...

  7. Measurements of Caesium-137 in Finnish Lapps in 1962-1964 by a Mobile Whole-Body Counter

    International Nuclear Information System (INIS)

    The construction, calibration and use in-field investigations of a mobile whole-body counter of the type developed by K. Lidén et al, in Sweden are described. The lead shield of the present system (2 t) is located)in-the middle of a covered heavy truck. The subject is surrounded by a 4-cm thick lead coffin, the Nal(Tl) crystal (5 an-diam. x 3 in) being protected from the other directions than the coffin by 8 cm of lead. The instrumentation consists of a 512-channel analyser, printer, x, y-recorder, and stabilizer, which are kept in shock- and dust-proof boxes during transport. The truck is provided with a thermostated heating system and contains two dressing cubicles. The system was calibrated for caesium-137 by two methods: (1) By administering per os a precisely known amount (200 to 300 nc) caesium-137 to several subjects and determining the counting efficiency after 3 to 6 d. The excreted portion of caesium-137 was determined by collecting and analysing the faeces and urine. (2) By counting a plastic phantom filled with 70.kg of a solution containing 1552 nc caesium-137. The first method gave a 4,6% higher efficiency than the second. The efficiency obtained by the first method was adopted as, the true calibration. This was also checked by three inter-calibration measurements with two other whole-body counting laboratories. The agreement was good (within 1 to 4%). For potassium a preliminary calibration was made by the use of the phantom. The efficiency is 2.51 cpm/nc caesium-137 (0.60- 0.72 MeV, 20 channels), and 0.145 cpm/g K (1.38- 1.55 MeV, 30 channels). When the truck is parked on rock, the corresponding background counts with a 70 kg sugar phantom-are 77 cpm and, 58 cpm, respectively. On sandy soil the background is about half of that on rock. With this mobile counter three field investigations were carried out in Finnish Lapland. In May 1962 218 Lapps statistically representative groups from the three Finnish Lapp countries, Inari, Karesuanto and Utsjoki

  8. Radioactive caesium in Boreal forest landscapes - Dynamics and transport in food webs. Summary of research 1986-1996

    Energy Technology Data Exchange (ETDEWEB)

    Bergman, R.; Nylen, T.; Palo, T

    1998-12-01

    The need for - but also the paucity of - radioecological knowledge concerning the boreal forest became particularly apparent after the nuclear power plant accident in Chernobyl in April 1986. As a consequence several new projects were initiated in the Nordic countries with particular focus on the behaviour of radioactivecaesium in terrestrial and aquatic systems characteristic for the Fenno-Scandinavian landscapes. Among these new projects a multi-disciplinary co-operation in Umeaa between scientists at the Swedish University of Agricultural Sciences, and the Defence Research Establishment emerged. Initially this joint work focused mainly on descriptions of the dynamic changes of the content of radioactive caesium in soil-plant and animal communities in the county of Vaesterbotten. Most of the studies have been performed at the Vindeln experimental forest, 60 km NW of Umeaa. Plants of key interest were: bilberry (Vaccinium myrtillus), birch (Betula spp.), and pine (Pinus sylvestris), and among the animals: the moose (Alces alces) and a small rodent, the forest vole (Clethrionomus glareolus). Gradually over the past ten years the research has entered the stage where the specific causes of the caesium behaviour have been addressed - partly by the help of models developed for simulating forest ecosystems, partly by complementary field experiments. This paper reviews our main findings on this theme concerning the behaviour of radioactive caesium in boreal landscapes and significant pathways to man, as has become apparent from the radioecological co-operation dating from about ten years back. A list of the publications arising from these studies since 1986 is also presented in this report.

  9. THREE-YEAR RETENTION OF RADIOACTIVE CAESIUM IN THE BODY OF TEPCO WORKERS INVOLVED IN THE FUKUSHIMA DAIICHI NUCLEAR POWER STATION ACCIDENT.

    Science.gov (United States)

    Nakano, T; Tani, K; Kim, E; Kurihara, O; Sakai, K; Akashi, M

    2016-09-01

    Direct measurements of seven highly exposed workers at the Tokyo Electric Power Company Fukushima Daiichi Nuclear Power Station accident have been performed continuously since June 2011. Caesium clearance in the monitored workers is in agreement with the biokinetic models proposed by the International Commission on Radiological Protection. After 500 d from the initial measurement, however, the caesium clearance slowed. It was thought to be unlikely that additional Cs intake had occurred after the initial intake, as activity in foods was kept low. And, the contribution from the detector over the chest was enhanced with time. This indicates that insoluble Cs particles were inhaled and a long metabolic rate showed.

  10. The utilization of caesium 137 in studying soil degradation; L`utilisation du cesium 137 pour la connaissance de la degradation des sols

    Energy Technology Data Exchange (ETDEWEB)

    Wicherek, S.; Veyret, Y. [Centre de Biogeographie-Ecologie, 92 - Saint -Cloud (France); Bernard, C. [Ministere de l`Agriculture, des Pecheries et de l`Alimentation, Quebec (Canada)

    1994-12-31

    The caesium 137 isotope is distributed in the atmosphere during nuclear explosions, and is absorbed in the upper horizons of the soil on reaching the ground. When it is incorporated in the fine fraction of the soil, caesium 137 measurement allows movements affecting cultivated lands (mass movements, runoff effects, wind action) and rate of soil degradation over half a century to be evaluated. Vegetal cover and techniques of soil utilization must be considered; this method has been tested on a watershed in the Parisian Basin. 5 figs., 26 refs.

  11. Isothermal and non-isothermal torrefaction characteristics and kinetics of microalga Scenedesmus obliquus CNW-N.

    Science.gov (United States)

    Chen, Wei-Hsin; Wu, Zih-Ying; Chang, Jo-Shu

    2014-03-01

    Isothermal and non-isothermal torrefaction characteristics and kinetics of microalga Scenedesmus obliquus (S. obliquus) CNW-N are studied using thermogravimetric analysis. The pyrolysis of S. obliquus CNW-N with increasing temperature is characterized by four-stage decomposition. Depending on the torrefaction temperature, light, mild, and severe torrefaction from the weight loss and the maximum decomposition rate of the microalga can be classified. Under the same average temperature and torrefaction duration, non-isothermal torrefaction gives more severe pretreatment than the isothermal one. Increasing the heating rate of non-isothermal torrefaction also intensifies the pretreatment severity. Therefore, microalgae can be torrefied via non-isothermal torrefaction in a shorter time under the same pretreatment extent. The atomic H/C ratio in the microalga decreases with increasing torrefaction severity, whereas the atomic O/C ratio rises. The analysis suggests that the activation energy of isothermal torrefaction is 57.52×10(3)Jmol(-1), while it is between 40.14×10(3) and 88.41×10(3)Jmol(-1) for non-isothermal torrefaction.

  12. Modeling of Experimental Adsorption Isotherm Data

    Directory of Open Access Journals (Sweden)

    Xunjun Chen

    2015-01-01

    Full Text Available Adsorption is considered to be one of the most effective technologies widely used in global environmental protection areas. Modeling of experimental adsorption isotherm data is an essential way for predicting the mechanisms of adsorption, which will lead to an improvement in the area of adsorption science. In this paper, we employed three isotherm models, namely: Langmuir, Freundlich, and Dubinin-Radushkevich to correlate four sets of experimental adsorption isotherm data, which were obtained by batch tests in lab. The linearized and non-linearized isotherm models were compared and discussed. In order to determine the best fit isotherm model, the correlation coefficient (r2 and standard errors (S.E. for each parameter were used to evaluate the data. The modeling results showed that non-linear Langmuir model could fit the data better than others, with relatively higher r2 values and smaller S.E. The linear Langmuir model had the highest value of r2, however, the maximum adsorption capacities estimated from linear Langmuir model were deviated from the experimental data.

  13. Low dose rate caesium-137 implant time of intracavitary brachytherapy source of a selected oncology center in Ghana

    OpenAIRE

    John Owusu Banahene; Emmanuel Ofori Darko; Baffour Awuah

    2015-01-01

    Background: The treatment time taken for a radioactive source is found to be very important in intracavitary brachytherapy treatment. The duration of the treatment time depends on the prescribed dose requested to a reference point and the calculated dose rate to the same point. The duration of the treatment time of source is found to depend on the tumour stage. In this work, the treatment time of implant has been calculated for a Caesium-137 low dose rate brachytherapy source at an oncology f...

  14. Poly[μ-aqua-μ5-[2-(2,3,6-tri­chloro­phenyl)acetato]-caesium

    OpenAIRE

    Graham Smith

    2013-01-01

    In the structure of the title complex, [Cs(C8H4Cl3O2)(H2O)]n, the caesium salt of the commercial herbicide fenac [(2,3,6-trichlorophenyl)acetic acid], the irregular eight-coordination about Cs+ comprises a bidentate O:Cl-chelate interaction involving a carboxylate-O atom and an ortho-related ring-substituted Cl atom, which is also bridging, a triple-bridging carboxylate-O atom and a bridging water molecule. A two-dimensional polymer is generated, lying parallel to (100), within which there ar...

  15. First performance results of PTB's atomic caesium fountain and a study of contributions to its frequency instability.

    Science.gov (United States)

    Weyers, S; Bauch, A; Hubner, U; Schroder, R; Tamm, C

    2000-01-01

    At the Physikalisch-Technische Bundesanstalt (PTB), an atomic caesium fountain was constructed. Ramsey fringes with a full width at half maximum (FWHM) of 0.86 Hz were obtained by launching the atoms to a height of 83 cm above the cooling region (40 cm above the microwave cavity center). A first measurement of the homogeneity of the magnetic flux density yields 0.33 nT (rms), only 0.16% of the mean value of 0.205 muT used in normal operation. The inherent elementary noise contributions of the fountain and of a thermal beam atomic clock are compared in some detail.

  16. Caesium-137 soil sampling and inventory variability in reference locations: A literature survey

    Science.gov (United States)

    Sutherland, Ross A.

    1996-01-01

    Soil sampling design, the number of samples collected and the lateral variation of caesium-137 (137Cs) in uneroded reference locations were extracted from previously published work. The focus was on published work which used 137Cs reference inventory (Bq m-2) for qualitative or quantitative estimation of sediment redistribution (SRD) within the landscape. The objective of this study was to address one of the methodological concerns facing the 137Cs technique - that is, the lack of a rigorous statistical treatment of reference locations. The limited attention paid to the reference location is not justified as true estimates of SRD are based on the assumption of an unbiased, independent, random probability sample estimate, commonly the arithmetic mean. Results from the literature survey indicated that only 11% of the reference locations sampled for 137Cs expressly stated that a probability sampling design was used (transect or systematic-aligned grid). The remaining locations were generally sampled using a non-probability based design, more commonly known as haphazard sampling. Of the 75 reference study areas identified only 40 provided enough information to determine the dispersion around the mean, and from this the coefficient of variation (CV) was calculated for all available data. The median CV was 19·3%, with 95% confidence limits of 13·0-23.4%, indicating that approximately 11 random, independent samples would generally be necessary to adequately quantify the reference 137Cs area activity with an allowable error of 10% at 90% confidence. Further analysis indicated that only one-third of the studies sampled a sufficient number of 137Cs reference locations. This value would actually be lower as sampling frameworks were based on non-probability sampling procedures. For 137Cs reference locations it is recommended that a probability sampling design be utilized, preferably the systematic-aligned grid method, and as a minimum first-order estimate about 11 samples

  17. Caesium removal from fuel pond water using a composite ion exchanger containing nickel hexacyanoferrate

    International Nuclear Information System (INIS)

    Spent fuel elements from the Bohunice A1 reactor were stored in a pond. To limit corrosion of the cladding, they were held within thimbles which contained a corrosion inhibiting solution of potassium chromate (Chrompik). This proved to be not effective enough, fuel pins did fail, releasing significant amounts of radioactive caesium and also, due to hydrogen gas pressurisation, significant amounts of contaminated Chrompik were released into the pond together with approximately 100 TBq of Cs-137. This paper presents the work undertaken to remove this Cs-137 as part of the first phase of decommissioning the pond. The design is based on a skid mounted unit, comprising a shielded mechanical filter unit and a shielded ion exchange (IX) column unit, with interconnecting pipework and valves. The IX column is housed within a lead shielded overpack and connections to it are made by self-sealing quick release couplings. The IX column is of upward flow design and filled with a composite ion exchanger containing Nickel Hexacyanoferrate (II). The IX column packages may be stored within their own shielding once spent. Two operational runs have been completed, removing 25 TBq of Cs137 in each run. With a fresh column, the Decontamination Factor (DF) for Cs-137 uptake was initially over 5000. The DF then fell slowly over the first 1000 bed volumes to 3500, where it remained for most of the run. The run was terminated when calculations indicated that the column packing had absorbed the specified maximum loading of 25 TBq of Cs137. At this point the DF was 1500

  18. Applicability of Different Isothermal EOS at Nanomaterials

    Directory of Open Access Journals (Sweden)

    Deepika P. Joshi

    2013-01-01

    Full Text Available The present study explains the behaviour of nanomaterials such as AlN, CdSe, Ge, WC, and Ni- and Fe-filled-MWCNTs under high pressure. Among the number of isothermal EOSs available, we prefer only two parameter-based isothermal equations (i.e., Murnaghan equation, usual Tait's equation, Suzuki equation and Shanker equation. The present work shows the theoretical study of thermo-elastic properties especially relative compression (V/V0, isothermal bulk modulus (KP/K0, and compressibility (αP/α0 of nanomaterials. After comparing all formulations with available experimental data, we conclude that pressure dependence of relative compression (V/V0 for the nanomaterials, are in good agreement for all the equations at lower pressure range. At higher pressure range, Suzuki and Shanker formulations show some deviation from experimental values.

  19. Higher order Godunov schemes for isothermal hydrodynamics

    Science.gov (United States)

    Balsara, Dinshaw S.

    1994-01-01

    In this paper we construct higher order Godunov schemes for isothermal flow. Isothermal hydrodynamics serves as a good representation for several systems of astrophysical interest. The schemes designed here have second-order accuracy in space and time and some are third-order accurate for advection. Moreover, several ingredients of these schemes are essential components of even higher order. The methods designed here have excellent ability to represent smooth flow yet capture shocks with high resolution. Several test problems are presented. The algorithms presented here are compared with other algorithms having a comparable formal order of accuracy.

  20. The Use of Caesium-137 Measurements for Assessing Soil Erosion and Sedimentation in the Riva Basin (Istanbul, NW Turkey)

    International Nuclear Information System (INIS)

    The paper summarizes the findings of an assessment of soil redistribution in the Riva basin, upstream of the Omerli reservoir, based on use of the fallout radionuclide Caesium-137. This reservoir is located at the eastern side of Istanbul, Turkey, and is the main provider for water to Istanbul. In the Riva basin, soil erosion and associated sediment deposition and potential mass movements are natural landscape forming processes. However, these processes are being accelerated by human intervention, creating a serious threat for sustainable intensification of the agricultural production, watershed management and the conservation of the local natural resources. To determine soil redistribution rates and patterns using the fallout radionuclide approach, samples were collected from an uncultivated flat reference sites and the cultivated sloping farmland (two transects). According to the results of gamma spectroscopy measurements of Caesium-137 and the outputs from the proportional model and simplified mass balance model for both transects, erosion rates varied between -2.4 t ha-1 a-1 and -36.0 t ha-1 a-1 and deposition rates between +1.7 t ha-1 a-1 and +10.5 t ha-1 a-1. (author)

  1. The burden of cesium 137 in forest clerks; Die Belastung mit Caesium 137 bei Beschaeftigten der Forstverwaltung

    Energy Technology Data Exchange (ETDEWEB)

    Piechotowski, I.; Jaroni, J. [Landesgesundheitsamt Baden-Wuerttemberg, Stuttgart (Germany); Link, B. [Arbeits- und Sozialministerium des Landes Baden-Wuerttemberg, Stuttgart (Germany); Groezinger, O. [Ministerium fuer Umwelt und Verkehr des Landes Baden-Wuerttemberg, Stuttgart (Germany)

    2000-07-01

    In 47 forest clerks from the regions Ortenau and Oberschwaben in south-west Germany the incorporation of cesium 137 and potassium 40 was measured in autumn 1994. Soil burden as well as burden of nutrition with cesium 137 are different in these regions for geological reasons and as a result of the nuclear accident of Chernobyl. Caused by low content of clay in Oberschwaben, the transfer of cesium to plants is assisted. Heavy rainfall after the nuclear accident led to an additional increase of burden. The median of the concentration of cesium 137 was 1.4 Bq/kg body weight. The median for potassium 40 was 58 Bq/kg body weight. For cesium 137 regional differences were observed. For persons from Oberschwaben the median for cesium 137 was with 2.8 Bq/kg body weight clearly higher than for persons from Ortenau with 0,6 Bq/kg body weight. Concerning nutrition habits, the clearest difference was found comparing persons who had ate a minimum of four portions of deer from the surroundings within the last four weeks with persons who had ate less than four portions of deer from the surroundings within the last four weeks. The difference was greater in Oberschwaben than in Ortenau. The effective dose of cesium 137 calculated on the basis of the incorporation is very low compared to natural radiation. This is also valid for persons from Oberschwaben. (orig.) [German] Im Herbst 1994 wurde bei insgesamt 47 Bediensteten der Forstverwaltung aus den Regionen Ortenaukreis und Oberschwaben die Inkorportation an Caesium 137 und Kalium 40 gemessen. Sowohl die Bodenbelastung als auch die Belastung von Nahrungsmitteln mit Caesium 137 unterscheiden sich in diesen Gebieten bedingt durch geologische Besonderheiten und in Folge des Reaktorunfalls von Tschernobyl. Aufgrund eines geringen Anteils an Tonerden wird in Oberschwaben der Caesiumtransfer in Pflanzen beguenstigt, eine zusaetzliche Erhoehung der Belastung erfolgte durch starke Niederschlaege nach dem Reaktorunfall. Die Konzentration fuer

  2. Performance Characteristics of an Isothermal Freeze Valve

    Energy Technology Data Exchange (ETDEWEB)

    Hailey, A.E.

    2001-08-22

    This document discusses performance characteristics of an isothermal freeze valve. A freeze valve has been specified for draining the DWPF melter at the end of its lifetime. Two freeze valve designs have been evaluated on the Small Cylindrical Melter-2 (SCM-2). In order to size the DWPF freeze valve, the basic principles governing freeze valve behavior need to be identified and understood.

  3. Isothermal Titration Calorimetry in the Student Laboratory

    Science.gov (United States)

    Wadso, Lars; Li, Yujing; Li, Xi

    2011-01-01

    Isothermal titration calorimetry (ITC) is the measurement of the heat produced by the stepwise addition of one substance to another. It is a common experimental technique, for example, in pharmaceutical science, to measure equilibrium constants and reaction enthalpies. We describe a stirring device and an injection pump that can be used with a…

  4. Analysis of the kinetic behaviour of iodine and caesium isotopes in the primary circuit of LWR's during severe fuel damage accidents

    International Nuclear Information System (INIS)

    This State of the Art report deals with the chemical behaviour of caesium and iodine in the primary system, focusing particularly on kinetic chemical aspects. In case of a postulated severe accident in a nuclear reactor, cesium and iodine fission products are among the major contributors to health harm because of their high volatility and radiotoxicity. The extent of the release of such fission products to the environment depends on the effectiveness of transport through different structures in the reactor coolant system and within the reactor building. The release from fuel has been briefly studied; only those aspects concerning to iodine and caesium chemical forms when released have been reviewed; nevertheless the emphasis has been put on the transport of such elements and their species through the primary system. Some thermochemical equilibrium studies, applied to primary circuit conditions in LWR's, have been analyzed. The revision of the few kinetic studies existing on this matter has shown that kinetic behaviour of iodine and caesium isotopes in the primary circuit is an aspect poorly studied, despite the fact that kinetic aspects could have great importance on the chemical species formed under certain conditions. Other phenomena affecting iodine and caesium transport, besides chemical reactions, such as interactions with surfaces, aerosols or other chemical species have also been examined from available information on diverse experiments

  5. Regional variation of caesium-137 in minke whales ¤Balaenoptera acutorostrata¤ from West Greenland, the Northeast Atlantic and the North Sea

    DEFF Research Database (Denmark)

    Born, E.W.; Dahlgaard, H.; Riget, F.F.;

    2002-01-01

    Levels of radioactive caesium (Cs-137) were determined in minke whales (Balaenoptera acutorostrata) from West Greenland, the Northeast Atlantic region and the North Sea. The sample consisted of muscle tissue from 135 minke whales caught in 1998 in 7 different areas: West Greenland, n = 44; East G...

  6. EU Migration Policy

    OpenAIRE

    Kleinschmidt, Harald

    2004-01-01

    I shall confine myself in this paper to international migration as migration across international borders.I do so despite the fact that,still today,international migration accounts only for a small share of migration at large.Likewise,I shall deal widh voluntary migration and shall thus exclude,deportation ...

  7. Studies of nuclear-waste migration in geologic media. Annual report, October 1977-September 1978

    International Nuclear Information System (INIS)

    The first phenomenon studied is incomplete water-nuclide-rock reaction because of slow reaction kinetics. A kinetic factor derived from the experimental results for strontium migration through glauconite (a hydrous silicate) was expressed in terms of the linear flow rate of solution and can be used to predict migration due to solution flow at rates of 0 to about 12 cm/min (60 km/y). Continuous-flow infiltration experiments with americium in fissures gave results that are predicted by a migration model that includes kinetic factors measured in experiments with static fluids. The results suggest that kinetic factors are as important as equilibrium adsorption parameters in predicting nuclide migration. The second phenomenon studied was the amount of adsorbed nuclide not being proportional to the nuclide concentration in solution (nonlinear adsorption isotherm). For cesium adsorption on limestone, a nonlinear isotherm was found to occur in the range of initial cesium concentrations from about 10-3 to 10-9M. This adsorption property was confirmed by results of column-infiltration experiments in which cesium migration through oolitic limestone was found to be sensitive to the amount of cesium in solution. The existence of a nonlinear isotherm precludes the use of a single partition value (K/sub D/) to describe cesium migration in limestone at cesium concentrations above about 10-9M. Therefore, the effects of nonlinear isotherms are germane to nuclide migration. 24 figures, 6 tables

  8. Coronal Loops: Evolving Beyond the Isothermal Approximation

    Science.gov (United States)

    Schmelz, J. T.; Cirtain, J. W.; Allen, J. D.

    2002-05-01

    Are coronal loops isothermal? A controversy over this question has arisen recently because different investigators using different techniques have obtained very different answers. Analysis of SOHO-EIT and TRACE data using narrowband filter ratios to obtain temperature maps has produced several key publications that suggest that coronal loops may be isothermal. We have constructed a multi-thermal distribution for several pixels along a relatively isolated coronal loop on the southwest limb of the solar disk using spectral line data from SOHO-CDS taken on 1998 Apr 20. These distributions are clearly inconsistent with isothermal plasma along either the line of sight or the length of the loop, and suggested rather that the temperature increases from the footpoints to the loop top. We speculated originally that these differences could be attributed to pixel size -- CDS pixels are larger, and more `contaminating' material would be expected along the line of sight. To test this idea, we used CDS iron line ratios from our data set to mimic the isothermal results from the narrowband filter instruments. These ratios indicated that the temperature gradient along the loop was flat, despite the fact that a more complete analysis of the same data showed this result to be false! The CDS pixel size was not the cause of the discrepancy; rather, the problem lies with the isothermal approximation used in EIT and TRACE analysis. These results should serve as a strong warning to anyone using this simplistic method to obtain temperature. This warning is echoed on the EIT web page: ``Danger! Enter at your own risk!'' In other words, values for temperature may be found, but they may have nothing to do with physical reality. Solar physics research at the University of Memphis is supported by NASA grant NAG5-9783. This research was funded in part by the NASA/TRACE MODA grant for Montana State University.

  9. Combined Use of Caesium-137 Methodology and Conventional Erosion Measurements in the Mistelbach Watershed (Austria)

    International Nuclear Information System (INIS)

    Over the past thirty years, many studies identified water erosion worldwide as one of the major causes of soil degradation on arable land. However, in order to develop appropriate soil conservation strategies more quantitative long term assessments of the soil erosion process are still needed. Therefore, in the present study, the magnitude of erosion and sedimentation was quantified using Fallout RadioNuclides (FRN) in combination with conventional runoff plots measurements in a small agricultural watershed under conventional and conservation cropping practices at Mistelbach located in Austria. A preliminary test of the use of the FRN Caesium-137 (137Cs) was successfully implemented in the Mistelbach watershed. A valid reference site - a small forest within the watershed - was identified and characterized (texture and physicochemical parameters). In this undisturbed area, a classical exponential depth distribution of 137Cs activity was found with 90% of the 137Cs in the first 15 cm; no 137Cs was detected below 20 cm. Seventy six (76) samples were collected on integrated grids basis. The reference value was 1954±91 Bq m-2 (mean ± 95% confidence interval) with a coefficient of variation of 20.4%. Two one meter soil profiles were also collected in the sedimentation area and analysed using the 137Cs method combined with the conversion model Mass Balance Model 2 (MBM 2). Using the 137Cs data, the sedimentation rates down slope of the field containing the runoff plots were estimated to be 26 t-1 ha-1 a-1 using the 137Cs depth distribution profile and at 20 t-1 ha-1 a-1 using the MBM 2. In the lowest part of the watershed sedimentation rates of up to 51 t-1 ha-1 a-1 were estimated through the 137Cs depth distribution profile. These results were linked to long term erosion measurements (1994-2006) from runoff plots just up-slope from the sedimentation area. The average soil erosion reached 29 t ha-1 a-1 from the conventional tilled plot, 4 t ha-1 a-1 from the

  10. Sediment Budgets and Source Determinations Using Fallout Caesium-137 in a Semiarid Rangeland Watershed, Arizona, USA

    International Nuclear Information System (INIS)

    Analysis of soil redistribution patterns and sediment sources in semiarid and arid watersheds provides information for understanding watershed sediment budgets and for implementing management practices to improve rangeland conditions and reduce sediment loads in streams. The purpose of this research was to develop sediment budgets and to identify potential sediment sources using 137Caesium (137Cs) and other soil properties in a series of small semiarid subwatersheds on the USDA ARS Walnut Gulch Experimental Watershed near Tombstone, Arizona, USA. Soils were sampled in a grid pattern on two small subwatersheds and along transects associated with soils and geomorphology on six larger subwatersheds. Soil samples were analyzed for 137Cs and selected physical and chemical properties (i.e. bulk density, rocks, particle size, soil organic carbon). Suspended sediment samples collected at flume sites on the Walnut Gulch Experimental Watershed were also analyzed for the same properties. Sediment budgets measured using 137Cs inventories for a small shrub and a small grass subwatersheds found eroding areas in these watersheds were losing 5.6 and 3.2 t ha-1 a-1, respectively; however, a sediment budget for each of the small subwatersheds, including depositional areas, found net soil loss to be 4.3 t ha-1 a-1 from the shrub watershed and near zero t ha-1 a-1 from the grass subwatershed. The suspended sediments collected at the flumes of the larger subwatersheds were enriched in silt, clay, and 40K, but not for 137Cs. Using multivariate mixing models to determine sediment source indicated that the shrub dominated subwatersheds were contributing most of the suspended sediments measured at the outlet flume of the Walnut Gulch Experimental Watershed. Both methodologies (sediment budgets and sediment source analyses) indicate that shrub dominated systems provide more suspended sediments to the stream systems. These studies also suggest that sediment yields measured at the outlet of a

  11. Neuronal Migration Disorders

    Science.gov (United States)

    ... Enhancing Diversity Find People About NINDS NINDS Neuronal Migration Disorders Information Page Table of Contents (click to ... being done? Clinical Trials Organizations What are Neuronal Migration Disorders? Neuronal migration disorders (NMDs) are a group ...

  12. Research on Protocol Migration

    Institute of Scientific and Technical Information of China (English)

    汪芸; 顾冠群; 等

    1996-01-01

    This paper elaborates the concept and model of protocol migration in network interconnection.Migration strategies and principles are discussed and several cases are studied in detail which show the basic procedure and techniques used in protocol migration.

  13. Migration of birds

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report covers the migration of birds. Topics covered include why birds migrate, when birds migrate, speed, altitude, courses, distance, major flyways and...

  14. Internationalization and migration pressure.

    Science.gov (United States)

    Kultalahti, O

    1994-01-01

    The author first develops the concept of migration pressure, which is defined as the growth in the number of people wishing to migrate and the barriers preventing them from so doing. Both macro- and micro-level factors affecting migration pressure are identified. Historical trends in migration pressure in Finland are then discussed. The author then applies this concept to the analysis of current Finnish migration trends. The primary focus is on international migration.

  15. Isothermal blast wave model of supernova remnants

    Science.gov (United States)

    Solinger, A.; Buff, J.; Rappaport, S.

    1975-01-01

    The validity of the 'adiabatic' assumption in supernova-remnant calculations is examined, and the alternative extreme of an isothermal blast wave is explored. It is concluded that, because of thermal conductivity, the large temperature gradients predicted by the adiabatic model probably are not maintained in nature. Self-similar solutions to the hydrodynamic equations for an isothermal blast wave have been found and studied. These solutions are then used to determine the relationship between X-ray observations and inferred parameters of supernova remnants. A comparison of the present results with those for the adiabatic model indicates differences which are less than present observational uncertainties. It is concluded that most parameters of supernova remnants inferred from X-ray measurements are relatively insensitive to the specifics of the blast-wave model.

  16. Isothermal calorimetry on enzymatic biodiesel production

    DEFF Research Database (Denmark)

    Fjerbæk, Lene

    2008-01-01

    information about effects taking place when using lipases immobilized on an inert carrier for transesterification of a triglyceride and an alcohol as for biodiesel production. The biodiesel is produced by rapeseed oil and methanol as well as ethanol and a commercial biocatalyst Novozym 435 from Novozymes...... containing a Candida Antarctica B lipase immobilized on an acrylic resin. The reaction investigated is characterized by immiscible liquids (oil, methanol, glycerol and biodiesel) and enzymes imm. on an inert carrier during reaction, which allows several effects to take place that during normal reaction...... conditions can not be elucidated. These effects have been observed with isothermal calorimetry bringing forth new information about the reaction of enzymes catalyzing transesterification. Enzymatic biodiesel production has until now not been investigated with isothermal microcalorimetry, but the results...

  17. Fast migration of low-mass planets in radiative discs

    Science.gov (United States)

    Pierens, A.

    2015-12-01

    Low-mass planets are known to undergo Type I migration and this process must have played a key role during the evolution of planetary systems. Analytical formulae for the disc torque have been derived assuming that the planet evolves on a fixed circular orbit. However, recent work has shown that in isothermal discs, a migrating protoplanet may also experience dynamical corotation torques that scale with the planet drift rate. The aim of this study is to examine whether dynamical corotation torques can also affect the migration of low-mass planets in non-isothermal discs. We performed 2D radiative hydrodynamical simulations to examine the orbital evolution outcome of migrating protoplanets as a function of disc mass. We find that a protoplanet can enter a fast migration regime when it migrates in the direction set by the entropy-related horseshoe drag and when the Toomre stability parameter is less than a threshold value below which the horseshoe region contracts into a tadpole-like region. In that case, an underdense trapped region appears near the planet, with an entropy excess compared to the ambient disc. If the viscosity and thermal diffusivity are small enough so that the entropy excess is conserved during migration, the planet then experiences strong corotation torques arising from the material flowing across the planet orbit. During fast migration, we observe that a protoplanet can pass through the zero-torque line predicted by static torques. We also find that fast migration may help in disrupting the mean-motion resonances that are formed by convergent migration of embryos.

  18. A Short Note on Non-isothermal Diffusion Models

    Directory of Open Access Journals (Sweden)

    T. Ficker

    2003-01-01

    Full Text Available Asymptotic behaviour of the DIAL and DRAL non-isothermal models, derived previously for the diffusion of water vapour through a porous building structure, is studied under the assumption that the initially non-isothermal structure becomes purely isothermal.

  19. Temperature effects for isothermal polymer crystallization kinetics

    OpenAIRE

    Yang, Jiao; McCoy, Benjamin J; Madras, Giridhar

    2005-01-01

    We adopt the cluster size distribution model to investigate the effect of temperature on homogeneous nucleation and crystal growth for isothermal polymer crystallization. The model includes the temperature effects of interfacial energy, nucleation rate, growth and dissociation rate coefficients, and equilibrium solubility. The time dependencies of polymer concentration, number and size of crystals, and crystallinity (in Avrami plots) are presented for different temperatures. The denucleation ...

  20. Analysis of Cooperativity by Isothermal Titration Calorimetry

    OpenAIRE

    Alan Brown

    2009-01-01

    Cooperative binding pervades Nature. This review discusses the use of isothermal titration calorimetry (ITC) in the identification and characterisation of cooperativity in biological interactions. ITC has broad scope in the analysis of cooperativity as it determines binding stiochiometries, affinities and thermodynamic parameters, including enthalpy and entropy in a single experiment. Examples from the literature are used to demonstrate the applicability of ITC in the characterisation of coop...

  1. ISOTHERMAL PYROLYSIS OF KRAFT PULP MILL SLUDGE

    OpenAIRE

    Syamsudin Syamsudin; Herri Susanto; Subagjo Subagjo

    2014-01-01

    Kraft pulp mill sludge cake composed of rejected wood fibers and activated sludge microorganisms. With a heating value about 14 MJ/kg (dried basis), this type of biomass had a potential as an alternative energy source. Unfortunately, it had an ash content of 27.6% and a moisture content of 80%. For reducing moisture content with minimum energy consumption, a combination of mechanical dewatering and thermal drying was studied previously. Meanwhile, experiments on isothermal pyrolysis had been ...

  2. Quasistatic isothermal evolution of shape memory alloys

    OpenAIRE

    Frigeri, Sergio; Krejčí, Pavel; Stefanelli, Ulisse

    2011-01-01

    This paper focuses on a three-dimensional phenomenological model for the isothermal evolution of a polycrystalline shape memory alloy. The model, originally proposed by Auricchio, Taylor, and Lubliner in 1997, is thermodynamically consistent and reproduces the crucial martensitic reorientation effect as well as the tension-compression asymmetric behavior of the material. We prove the existence of a weak solution of the corresponding quasistatic evolution problem by passing to the limit within...

  3. Improved electron collection in fullerene via caesium iodide or carbonate by means of annealing in inverted organic solar cells

    Directory of Open Access Journals (Sweden)

    El Jouad Zouhair

    2014-05-01

    Full Text Available Inverted organic photovoltaic cells (IOPVCs, based on the planar heterojunction C60/CuPc, were grown using MoO3 as anode buffer layer and CsI or Cs2CO3 as cathode buffer layer (CBL, the cathode being an ITO coated glass. Work functions, Φf, of treated cathode were estimated using the cyclic voltammetry method. It is shown that Φf of ITO covered with a Cs compounds is decreased. This decrease is amplified by the annealing. It is shown that the thermal deposition under vacuum of the CBL induces a partial decomposition of the caesium compounds. In parallel, the formation of a compound with the In of ITO is put in evidence. This reaction is amplified by annealing, which allows obtaining IOPVCs with improved efficiency. The optimum annealing conditions is 150 °C for 5 min.

  4. The effect of organics on the sorption of strontium, caesium, iodine, neptunium, uranium and europium by glacial sand

    International Nuclear Information System (INIS)

    This study has been undertaken within the Commission of the European Communities MIRAGE II program on the determination of radionuclides in the geosphere. Preliminary batch sorption experiments have been carried out to study the behaviour of strontium, caesium, iodine, europium and uranium in a glacial sand-groundwater system. The effect of (i) the presence or absence of natural organic material and (ii) the addition of increasing quantities of EDTA or acetate on the distribution ratios was determined. In some cases speciation modelling was used as an aid to designing the experiments and interpreting the results. The aim of this work was to select suitable tracers for use in field experiments at Drigg. Cumbria and the results are intended to aid the design of future experiments rather than to provide a complete analysis of the radionuclide-organic interactions. 11 tabs., 49 refs

  5. Gigahertz optical memory with up to 20 dB gain via molecular quenching in caesium vapour

    CERN Document Server

    Thomas, S E; Kaczmarek, K T; Qiu, C; Brecht, B; Feizpour, A; Ledingham, P M; Walmsley, I A; Nunn, J; Saunders, D J

    2016-01-01

    Raman interactions in alkali vapours are used in applications such as atomic clocks, optical signal processing, generation of squeezed light and Raman quantum memories for temporal multiplexing. To achieve a strong interaction the alkali ensemble needs both a large optical depth and a high level of spin-polarisation. We implement a technique known as quenching using a molecular buffer gas which allows near-perfect spin-polarisation of over 99.5% in caesium vapour at high optical depths of up to $\\sim 10^5$; a factor of 4 higher than can be achieved without quenching. We use this system to explore efficient light storage with high gain in a GHz bandwidth Raman memory.

  6. Ultra-high and persistent optical depths of caesium in Kagom\\'e-type hollow-core photonic crystal fibres

    CERN Document Server

    Kaczmarek, Krzysztof T; Sprague, Michael R; Kolthammer, W Steven; Feizpour, Amir; Ledingham, Patrick M; Brecht, Benjamin; Poem, Eilon; Abdolvand, Amir; Russell, Philip St J; Walmsley, Ian A; Nunn, Joshua

    2015-01-01

    Alkali-filled hollow-core fibres are a promising medium for investigating light-matter interactions, especially at the single-photon level, due to the tight confinement of light and high optical depths achievable by light-induced atomic desorption. However, until now these large alkali vapour densities could only be generated for seconds at most once per day, severely limiting the practicality of the technology. Here we report the generation of highest observed transient ($>10^5$ for minutes) and highest observed persistent (>2000 for hours) optical depths of alkali vapours in hollow-core fibres to date, using a caesium-filled Kagom\\'e-type hollow-core photonic crystal fibre. Our results pave the way to light-matter interaction experiments in confined geometries requiring long operation times and large atomic number densities, such as single-photon-level light-matter interaction experiments and fundamental investigations of hot dense atomic gases.

  7. Solvothermal Synthesis of Caesium Tungsten Bronze in the Presence of Various Organic Acids and Its NIR Absorption Properties

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Chongshen; Yin, Shu; Sato, Tsugio [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai (Japan); Adachi, Kenji; Chonan, Takeshi, E-mail: bigguop@mail.tagen.tohoku.ac.jp [Ichikawa Research Laboratory, Sumitomo Metal Mining Co., Ltd (Japan)

    2011-10-29

    Nanoparticles of caesium tungsten bronze were successfully synthesized by solvothermal reactions in ethanol with the introduction of different organic fatty acids with various carbon numbers of 1 to 5. Compared to the sample prepared in pure ethanol, the samples obtained by mixed solvent of ethanol and fatty acids showed higher production yield, smaller particle size, more uniform particles size distribution and higher Cs/W atomic ratio. In addition, all of samples obtained using acids-ethanol mixed solvent exhibited higher visible light transmittance and greater NIR absorption performance, indicating the potential application for smart window and heat-ray shielding materials. The addition of acetic acid showed the best performance to facilitate the formation of well dispersed Cs{sub x}WO{sub 3} regular nanorods, leading to its excellent optical properties.

  8. Fast migration of low-mass planets in radiative discs

    CERN Document Server

    Pierens, Arnaud

    2015-01-01

    Low-mass planets are known to undergo Type I migration and this process must have played a key role during the evolution of planetary systems. Analytical formulae for the disc torque have been derived assuming that the planet evolves on a fixed circular orbit. However, recent work has shown that in isothermal discs, a migrating protoplanet may also experience dynamical corotation torques that scale with the planet drift rate. The aim of this study is to examine whether dynamical corotation torques can also affect the migration of low-mass planets in non-isothermal discs. We performed 2D radiative hydrodynamical simulations to examine the orbital evolution outcome of migrating protoplanets as a function of disc mass. We find that a protoplanet can enter a fast migration regime when it migrates in the direction set by the entropy-related horseshoe drag and when the Toomre stability parameter is less than a threshold value below which the horseshoe region contracts into a tadpole-like region. In that case, an un...

  9. An isothermal equation of state for solids

    International Nuclear Information System (INIS)

    An isothermal equation of state (EOS) for solids, recently suggested by the authors in the realistic form, V/V0=f(P), with relative volume as the dependent and the pressure as the independent variable, was shown to have an advantage for some close-packed materials in that it allows B'∞=(∂Bs/∂P)s(P→∞) to be fitted, and this is where the usual standard equations fail. In the present study, our EOS is applied to a number of inorganic as well as organic solids, including alloys, glasses, rubbers and plastics; varying widely in their bonding and structural characteristics, as well as in their bulk modulus values. A very good agreement is observed between the data and fits. The results obtained are compared with those from two well-known equations, expressible in the realistic form, proposed by Murnaghan and Luban. Further, the results are also compared with those from the widely used two- and three-parameter EOSs, expressible in the unrealistic form only, P=f(V/V0), proposed by Birch--and also with those from the EOS model of Keane in which B'∞ is explicitly expressed as an equation of state parameter. The results obtained from our model compare well to these EOSs. Our EOS, in general, yields the smallest mean-squared deviations between data and fits. The values of B'∞calculated from our EOS are compared with those from Keane's model. Further, we have studied the variation of B'∞with temperature using the experimental isotherms of Mo and W at 10 different temperatures ranging from 100 to 1000 K, and observed that the values of B'∞ yielded by our model and that of Keane vary, as expected, within a narrow range. Furthermore, our EOS is applied to study the stability of the fit parameters with variation in the pressure ranges with reference to the isothermal compression data on Mo and W--and also to study the variation of isothermal bulk modulus with pressure, with reference to the ultrasonic data on NaCl and noted a very good agreement with experiment

  10. Studies of nuclear waste migration in geologic media. Annual report, October 1978-September 1979

    Energy Technology Data Exchange (ETDEWEB)

    Seitz, M. G.; Rickert, P. G.; Couture, R. A.; Williams, J.; Meldgin, N.; Fried, S. M.; Friedman, A. M.; Steindler, M. J.

    1980-01-01

    Experimental results obtained this year confirm the results obtained in previous years - that nuclides migrating by fluid flow in rock often exhibit complex behavior not predicted by simple chromatographic-type models. A phenomenon found previously to lead to complex behavior for leached radionuclides is that the amount of adsorbed nuclide was not proportional to the nuclide concentration in solution (nonlinear adsorption isotherm). For cesium adsorption on limestone and on basalt, nonlinear isotherms were found this year to occur in the range of cesium concentrations in the groundwater of about 10/sup -3/ to 10/sup -9/M. Because cesium concentrations in this range can readily be attained by the leaching of solid waste by groundwater, the effects of nonlinear isotherms are germane to nuclide migration. This dependence of cesium migration on the leached concentration of cesium emphasizes the importance of treating the leaching and migration processes simultaneously such as is done in the leach-migration experiments performed in this work. The existence of nonlinear isotherms precludes the use of a single partition coefficient (K/sub d/) to describe cesium migration at an arbitrary cesium concentration above 10/sup -9/M. Nonetheless, nonlinear isotherms can be studied experimentally (e.g., to give K/sub d/ as a function of concentration) and effects of nonlinear adsorption can be predicted quantitatively. Comparison of results from column and batch tests indicate that, in addition to nonlinear adsorption, kinetic effects need to be considered in predicting nuclide migration from the partition coefficients measured in batch tests. Results of batch experiments of 2 weeks or longer duration pertained to migration expected only at the very lowest (< 50 m/y) groundwater flow rates of interest.

  11. Studies of nuclear waste migration in geologic media. Annual report, October 1978-September 1979

    International Nuclear Information System (INIS)

    Experimental results obtained this year confirm the results obtained in previous years - that nuclides migrating by fluid flow in rock often exhibit complex behavior not predicted by simple chromatographic-type models. A phenomenon found previously to lead to complex behavior for leached radionuclides is that the amount of adsorbed nuclide was not proportional to the nuclide concentration in solution (nonlinear adsorption isotherm). For cesium adsorption on limestone and on basalt, nonlinear isotherms were found this year to occur in the range of cesium concentrations in the groundwater of about 10-3 to 10-9M. Because cesium concentrations in this range can readily be attained by the leaching of solid waste by groundwater, the effects of nonlinear isotherms are germane to nuclide migration. This dependence of cesium migration on the leached concentration of cesium emphasizes the importance of treating the leaching and migration processes simultaneously such as is done in the leach-migration experiments performed in this work. The existence of nonlinear isotherms precludes the use of a single partition coefficient (K/sub d/) to describe cesium migration at an arbitrary cesium concentration above 10-9M. Nonetheless, nonlinear isotherms can be studied experimentally (e.g., to give K/sub d/ as a function of concentration) and effects of nonlinear adsorption can be predicted quantitatively. Comparison of results from column and batch tests indicate that, in addition to nonlinear adsorption, kinetic effects need to be considered in predicting nuclide migration from the partition coefficients measured in batch tests. Results of batch experiments of 2 weeks or longer duration pertained to migration expected only at the very lowest (< 50 m/y) groundwater flow rates of interest

  12. Migration and trade

    OpenAIRE

    Peter H. Egger; Ehrlich, Maximilian von; Nelson, Douglas R.

    2011-01-01

    Theoretical and empirical research in economics suggests that bilateral migration triggers bilateral trade through a number of channels. This paper assesses the functional form of the impact of migration on trade flows in a quasi-experimental setting. We provide evidence that the relationship is not log-linear. In particular, at small levels of migration (stocks) the elasticity of trade to migration is quite high, and it declines to zero at about 4,000 immigrants. If migration stocks exceed s...

  13. Adsorption isotherm of non-azeotropic solution onto porous adsorbents

    Science.gov (United States)

    Bono, A.; Ramlan, N. A.; Anisuzzaman, S. M.; Chu, C. M.; Farm, Y. Y.

    2016-06-01

    Adsorption isotherm is essential component in the understanding of the adsorption process. Several methods of the measurements, analysis and interpretation of adsorption from solution have been reported in the literature. Most of the measurements of adsorption isotherm from solution were involved the measurement of excess isotherm conducted at low region of sorbates concentration. Direct interpretation of excess adsorption isotherm as adsorption isotherm is always been practice. Therefore, in this work a study on the measurement of the adsorption isotherm from solution of non-azeotropic organic solvent mixture onto porous adsorbents for whole range of liquid concentration was conducted. The study included the measurement of excess adsorption isotherm using conventional technique. Theoretical analysis and interpretation of adsorption isotherm from the excess isotherm were conducted using Pseudo Ideal Adsorption, Gibbs Dividing Plane Model and Langmuir-Fruendlich binary isotherm model. For organic solvents, acetone and propanol were chosen as the adsorbates due to the non-azeotropic properties in the mixture. Activated carbon and silicalite were chosen as adsorbents due to the different in their porosity such as macro porous and micro porous structure. The result of the study has revealed that the adsorption isotherm of non-azeotropic mixture onto activated carbon and silicalite can be interpreted as monolayer type of adsorption.

  14. Artificial neural network modeling of phase volume fraction of Ti alloy under isothermal and non-isothermal hot forging conditions

    International Nuclear Information System (INIS)

    An artificial neural network (ANN) model was applied to simulate the phase volume fraction of titanium alloy under isothermal and non-isothermal hot forging condition. For isothermal hot forging process, equilibrium phase volume fraction at specific temperature was predicted. For this purpose, chemical composition of six alloy elements (i.e. AI, Y, Fe, 0, N, and C) and specimen temperature were chosen as input parameter. After that, phase volume fraction under non-isothermal condition was simulated again. Input parameters consist of initial phase volume fraction, equilibrium phase volume fraction at specific temperature, cooling rate, and temperature.The ANN model was coupled with the FE simulation in order to predict the variation of phase volume fraction during non-isothermal forging. Ti-6AI-4Y alloy was forged under isothermal and non-isothermal condition and then, the resulting microstructures were compared with simulated data

  15. Stability properties of an isothermal accretion disk

    International Nuclear Information System (INIS)

    A local stability analysis of an isothermal, transonic accretion disk around a non-rotating black hole is used to infer the time-dependent behaviour of linear perturbations. The three modes in the problem are one viscous Lightman-Eardley mode, which is always stable, and two acoustic modes, which are always overstable. If the growth rate is required to be greater than the escape rate, then the acoustic modes become stable in the outer region, and unstable in the innermost region, if the viscosity parameter α is greater than 0.5. (orig.)

  16. Magnetostatic atmospheres: A family of isothermal solutions

    International Nuclear Information System (INIS)

    Most models of large scale solar magnetic fields assume either that the fields are potential or that they are force free. We present a new, analytic, two parameter family of magnetic fields in equilibrium with isothermal plasma in a gravitational field. We discuss these models from the viewpoint of the insight into the balance of magnetic pressure gradient, and gravitational forces that they provide. We show that substantial deviations from the potential field configuration are obtained for plasma β of order unity, and we emphasize the variety of possible relationships between isobars and magnetic fieldlines. (orig.)

  17. Isothermal Gravitational Segregation: Algorithms and Specifications

    DEFF Research Database (Denmark)

    Halldórsson, Snorri; Stenby, Erling Halfdan

    2000-01-01

    New algorithms for calculating the isothermal equilibrium state of reservoir fluids under the influence of gravity are presented. Two types of specifications are considered: the specification of pressure and composition at a reference depth; and the specification of the total overall content...... of the reservoir, along with the reservoir geometry. It is shown how both types of calculations can be performed in an efficient and robust manner using volume-based thermodynamics. The new method makes it possible to evaluate the influence of reservoir geometry and gravity segregation on the hydrocarbon reserves...

  18. Isothermal calorimetry of enzymatic biodiesel reaction

    DEFF Research Database (Denmark)

    Fjerbæk Søtoft, Lene; Westh, Peter; Christensen, Knud Villy;

    2010-01-01

      Isothermal calorimetry ITC has been used to investigate enzymatic biodiesel production. The transesterification of rapeseed oil with methanol and ethanol was catalyzed by the immobilized lipase Novozym 435 at 40°C. The ITC-experiments clearly demonstrate the possibilities of investigating complex...... and composition change in the system, the heat of reaction at 40°C for the two systems has been determined to -9.8 ± 0.9 kJ/mole biodiesel formed from rapeseed oil and methanol, and - 9.3 ± 0.7 kJ/mole when rapeseed oil and ethanol is used....

  19. ISOTHERMAL PYROLYSIS OF KRAFT PULP MILL SLUDGE

    Directory of Open Access Journals (Sweden)

    Syamsudin Syamsudin

    2014-12-01

    Full Text Available Kraft pulp mill sludge cake composed of rejected wood fibers and activated sludge microorganisms. With a heating value about 14 MJ/kg (dried basis, this type of biomass had a potential as an alternative energy source. Unfortunately, it had an ash content of 27.6% and a moisture content of 80%. For reducing moisture content with minimum energy consumption, a combination of mechanical dewatering and thermal drying was studied previously. Meanwhile, experiments on isothermal pyrolysis had been carried out for further improvement on ultimate and proximate analysis of solid fuel. Final mass of char obtained from pyrolysis at 500oC was not significantly different from that of 700oC, so pyrolysis was considered to be optimum at 500oC. A char obtained from pyrolysis at temperature of 500oC had a pore surface area of 77.049 m2/g (highest among other temperatures. Kinetic of isothermal pyrolysis was well represented with a first order modified volumetric model with a frequency factor of 0.782 1/s and an activation of 34.050 kJ/mol.

  20. Return migration to Italy and labour migration.

    Science.gov (United States)

    Calvaruso, C

    1983-01-01

    The problems caused by large-scale return migration to Italy in recent years are considered. The importance of the additional skills and capital acquired by these migrants while abroad is stressed. Extensive data on the volume of return migration in the 1970s are included.

  1. Investigation of non-isothermal and isothermal gasification process of coal char using different kinetic model

    Institute of Scientific and Technical Information of China (English)

    Wang Guangwei; Zhang Jianliang; Shao Jiugang; Li Kejiang; Zuo Haibin

    2015-01-01

    Isothermal and non-isothermal gasification kinetics of coal char were investigated by using thermogravi-metric analysis (TGA) in CO2 atmosphere, and the experimental data were interpreted with the aids of random pore model (RPM), unreacted shrinking core model (URCM) and volume model (VM). With the increase of heating rate, gasification curve moves into high temperature zone and peak rate of gasification increases;with the increase of gasification temperature, gasification rate increases and the total time of gasification is shortened. The increase of both heating rate and gasification temperature could improve gasification process of coal char. Kinetics analysis indicates that experimental data agree better with the RPM than with the other two models. The apparent activation energy of non-isothermal and isother-mal gasification of coal char using RPM is 193.9 kJ/mol and 212.6 kJ/mol respectively, which are in accor-dance with reported data. Gasification process of coal char under different heating rates and different temperatures are predicted by the RPM derived in this study, and it is found that the RPM predicts the reaction process satisfactorily.

  2. On migration of primary/peritectic interface during interrupted directional solidification of Sn-Ni peritectic alloy

    Science.gov (United States)

    Peng, Peng; Li, Xinzhong; Li, Jiangong; Su, Yanqing; Guo, Jingjie; Fu, Hengzhi

    2016-04-01

    The migration of the primary/peritectic interface in local isothermal condition is observed in dendritic structure of Sn–Ni peritectic alloy after experiencing interrupted directional solidification. It was observed that this migration of primary Ni3Sn2/peritectic Ni3Sn4 interface towards the primary Ni3Sn2 phase was accompanied by migration of liquid film located at this interface. The migration velocity of this interface was confirmed to be much faster than that of peritectic transformation, so this migration was mostly caused by superheating of primary Ni3Sn2 phase below TP, leading to nucleation and migration of liquid film at this interface. This migration can be classified as a kind of liquid film migration (LFM), and the migration velocity at the horizontal direction has been confirmed to be much faster than that along the direction of temperature gradient. Analytical prediction has shown that the migration of liquid film could be divided into two stages depending on whether primary phase exists below TP. If the isothermal annealing time is not long enough, both the liquid film and the primary/peritectic interface migrate towards the primary phase until the superheated primary phase has all been dissolved. Then, this migration process towards higher temperature is controlled by temperature gradient zone melting (TGZM).

  3. Population, migration and urbanization.

    Science.gov (United States)

    1982-06-01

    Despite recent estimates that natural increase is becoming a more important component of urban growth than rural urban transfer (excess of inmigrants over outmigrants), the share of migration in the total population growth has been consistently increasing in both developed and developing countries. From a demographic perspective, the migration process involves 3 elements: an area of origin which the mover leaves and where he or she is considered an outmigrant; the destination or place of inmigration; and the period over which migration is measured. The 2 basic types of migration are internal and international. Internal migration consists of rural to urban migration, urban to urban migration, rural to rural migration, and urban to rural migration. Among these 4 types of migration various patterns or processes are followed. Migration may be direct when the migrant moves directly from the village to the city and stays there permanently. It can be circular migration, meaning that the migrant moves to the city when it is not planting season and returns to the village when he is needed on the farm. In stage migration the migrant makes a series of moves, each to a city closer to the largest or fastest growing city. Temporary migration may be 1 time or cyclical. The most dominant pattern of internal migration is rural urban. The contribution of migration to urbanization is evident. For example, the rapid urbanization and increase in urban growth from 1960-70 in the Republic of Korea can be attributed to net migration. In Asia the largest component of the population movement consists of individuals and groups moving from 1 rural location to another. Recently, because urban centers could no longer absorb the growing number of migrants from other places, there has been increased interest in the urban to rural population redistribution. This reverse migration also has come about due to slower rates of employment growth in the urban centers and improved economic opportunities

  4. Migration, Remittances and Growth

    OpenAIRE

    Nurgul Ukueva

    2011-01-01

    This paper analyzes the effect of migration and remittances on a small, open, migrant-sending country in the context of an endogenous growth model with technology transfers. The paper demonstrates that, due to a dynamic feedback effect from economic conditions to migration and from migration to economic development in an economy exposed to migration, initial conditions can determine its long-run steady state, leading to the rise of vicious or virtues circles of development. Countries with a l...

  5. Calculation of Thermodynamic Parameters for Freundlich and Temkin Isotherm Models

    Institute of Scientific and Technical Information of China (English)

    ZHANGZENGQIANG; ZHANGYIPING; 等

    1999-01-01

    Derivation of the Freundlich and Temkin isotherm models from the kinetic adsorption/desorption equations was carried out to calculate their thermodynamic equilibrium constants.The calculation formulase of three thermodynamic parameters,the standard molar Gibbs free energy change,the standard molar enthalpy change and the standard molar entropy change,of isothermal adsorption processes for Freundlich and Temkin isotherm models were deduced according to the relationship between the thermodynamic equilibrium constants and the temperature.

  6. Pyrolysis of petroleum pitches. 1. Non-isothermal kinetics

    OpenAIRE

    Okyay, Firuze; Yürüm, Yuda; Yurum, Yuda

    2012-01-01

    The chemical composition and reactivity of petroleum pitches under non-isothermal thermogravimetric conditions were studied. Thermogravimetry (TG) was used to study pyrolysis of petroleum pitches. Non-isothermal thermogravimetric data were used to evaluate the kinetics of the pyrolysis of this carbonaceous material. The paper reports application of Ozawa–Flynn–Wall model to deal with non-isothermal TG data for the evaluation of the activation energy corresponding to the pyrolysis of two diffe...

  7. Statistical Design in Isothermal Aging of Polyimide Resins

    Science.gov (United States)

    Sutter, James K.; Jobe, Marcus; Crane, Elizabeth A.

    1995-01-01

    Recent developments in research on polyimides for high temperature applications have led to the synthesis of many new polymers. Among the criteria that determines their thermal oxidative stability, isothermal aging is one of the most important. Isothermal aging studies require that many experimental factors are controlled to provide accurate results. In this article we describe a statistical plan that compares the isothermal stability of several polyimide resins, while minimizing the variations inherent in high-temperature aging studies.

  8. Adsorption isotherms for benzene on diatomites from China

    Institute of Scientific and Technical Information of China (English)

    YANG, Yu-Xianga; WU, Jie-Da; JIANG, Zhong-Liang; HUANG, Meng-Jian; CHEN, Rong-San; DAI, An-Bang

    2000-01-01

    In this paper, benzene adsorption isotherm and their hysteresis on two important local diatomites were determined at 25℃, ani their silicon hydroxyl group (SiOH) nunber was determined, their properties were reported, and the relationship between surface structure, surface SiOH number per nm2and adsorption isotherm with hysteresis was discussed. The specific surface was also calculated from the isotherms, and pore-size distribution was determined.

  9. Migration and Adult Education

    Science.gov (United States)

    Gois, William

    2007-01-01

    The objective of this paper is to highlight the role of adult education as a tool in addressing labour migration issues, specifically those concerning the protection of migrant workers' rights and the transformation of the impact of migration into positive holistic developmental gains. The view of labour migration as a means to forge the economic…

  10. On Marriage and Migration

    OpenAIRE

    Stark, Oded

    1988-01-01

    Marriage, migration and related phenomena such as marital stability, fertility and investment in human capital may be better explained by studying marriage and migration jointly. We thus proceed in this paper to explore the role of migration in obtaining joint labour-market and marriage-market equilibrium. This facilitates identification of several novel and testable hypotheses.

  11. Isothermal aging of three polyurethane elastomers

    Energy Technology Data Exchange (ETDEWEB)

    Guess, T.R.

    1996-05-01

    Two polyurethane systems, EN-7 and L-100, have a long history as encapsulants and coatings in Sandia programs. These materials contain significant amounts of toluene diisocyanate (TDI), a suspect human carcinogen. As part of efforts to reduce the use of hazardous materials in the workplace, PET-90A, a polyurethane with less than 0.1% free TDI, was identified as a candidate for new applications and as a replacement for the more hazardous polyurethanes in selected programs. This report documents the results of a two-year accelerated aging study of PET-90A, EN-7, and L-100 polyurethane elastomers to characterize the effect of 135{degrees}F isothermal aging on selected physical, electrical, mechanical and thermal properties. In general, there was very little change in properties over the two year period for the three elastomers. The largest changes occurred in EN-7, which is the polyurethane with the longest service history in Sandia applications.

  12. A family of lowered isothermal models

    CERN Document Server

    Gieles, Mark

    2015-01-01

    We present a family of self-consistent, spherical, lowered isothermal models, consisting of one or more mass components, with parameterised prescriptions for the energy truncation and for the amount of radially biased pressure anisotropy. The models are particularly suited to describe the phase-space density of stars in tidally limited, mass-segregated star clusters in all stages of their life-cycle. The models extend a family of isotropic, single-mass models by Gomez-Leyton and Velazquez, of which the well-known Woolley, King and Wilson (in the non-rotating and isotropic limit) models are members. We derive analytic expressions for the density and velocity dispersion components in terms of potential and radius, and introduce a fast model solver in PYTHON (LIMEPY), that can be used for data fitting or for generating discrete samples.

  13. A family of lowered isothermal models

    Science.gov (United States)

    Gieles, Mark; Zocchi, Alice

    2015-11-01

    We present a family of self-consistent, spherical, lowered isothermal models, consisting of one or more mass components, with parametrized prescriptions for the energy truncation and for the amount of radially biased pressure anisotropy. The models are particularly suited to describe the phase-space density of stars in tidally limited, mass-segregated star clusters in all stages of their life-cycle. The models extend a family of isotropic, single-mass models by Gomez-Leyton and Velazquez, of which the well-known Woolley, King and Wilson (in the non-rotating and isotropic limit) models are members. We derive analytic expressions for the density and velocity dispersion components in terms of potential and radius, and introduce a fast model solver in PYTHON (LIMEPY), that can be used for data fitting or for generating discrete samples.

  14. Isothermal Titration Calorimetry to Characterize Enzymatic Reactions.

    Science.gov (United States)

    Mazzei, Luca; Ciurli, Stefano; Zambelli, Barbara

    2016-01-01

    Isothermal titration calorimetry (ITC) is a technique that measures the heat released or absorbed during a chemical reaction as an intrinsic probe to characterize any chemical process that involves heat changes spontaneously occurring during the reaction. The general features of this method to determine the kinetic and thermodynamic parameters of enzymatic reactions (kcat, KM, ΔH) are described and discussed here together with some detailed applications to specific cases. ITC does not require any modification or labeling of the system under analysis, can be performed in solution, and needs only small amounts of enzyme. These properties make ITC an invaluable, powerful, and unique tool to extend the knowledge of enzyme kinetics to drug discovery.

  15. Isothermal Titration Calorimetry of Chiral Polymeric Nanoparticles.

    Science.gov (United States)

    Werber, Liora; Preiss, Laura C; Landfester, Katharina; Muñoz-Espí, Rafael; Mastai, Yitzhak

    2015-09-01

    Chiral polymeric nanoparticles are of prime importance, mainly due to their enantioselective potential, for many applications such as catalysis and chiral separation in chromatography. In this article we report on the preparation of chiral polymeric nanoparticles by miniemulsion polymerization. In addition, we describe the use of isothermal titration calorimetry (ITC) to measure the chiral interactions and the energetics of the adsorption of enantiomers from aqueous solutions onto chiral polymeric nanoparticles. The characterization of chirality in nano-systems is a very challenging task; here, we demonstrate that ITC can be used to accurately determine the thermodynamic parameters associated with the chiral interactions of nanoparticles. The use of ITC to measure the energetics of chiral interactions and recognition at the surfaces of chiral nanoparticles can be applied to other nanoscale chiral systems and can provide further insight into the chiral discrimination processes of nanomaterials.

  16. Non-isothermal effects on Be disks

    CERN Document Server

    Vieira, Rodrigo G; Bjorkman, Jon E

    2016-01-01

    In the last decade, the viscous decretion disk model has emerged as the new paradigm for Be star disks. In this contribution, we propose a simple analytical model to estimate the continuum infrared excess arising from these circumstellar disks, in the light of the currently accepted scenario. We demonstrate that the disk can be satisfactorily described by a two component system: an inner optically thick region, which we call the pseudo-photosphere, and a diffuse outer part. In particular, a direct connexion between the disk brightness profile and the thermal structure is derived, and then confronted to realistic numerical simulations. This result quantifies how the non-isothermality of the disk ultimately affects both infrared measured fluxes and visibilities.

  17. Isothermal vapour flow in extremely dry soils

    Science.gov (United States)

    Todman, L. C.; Ireson, A. M.; Butler, A. P.; Templeton, M. R.

    2012-04-01

    In dry soils hydraulic connectivity within the liquid water phase decreases and vapour flow becomes a significant transport mechanism for water. The temperature or solute concentration of the liquid phase affects the vapour pressure of the surrounding air, thus temperature or solute gradients can drive vapour flows. However, in extremely dry soils where water is retained by adsorptive forces rather than capillarity, vapour flows can also occur. In such soils tiny changes in water content significantly affect the equilibrium vapour pressure in the soil, and hence small differences in water content can initiate vapour pressure gradients. In many field conditions this effect may be negligible compared to vapour flows driven by other factors. However, flows of this type are particularly significant in a new type of subsurface irrigation system which uses pervaporation, via a polymer tubing, as the mechanism for water supply. In this system, water enters the soil in vapour phase. Experiments were performed in laboratory conditions using marine sand that had previously been oven dried and cooled. This dry sand was used to represent the desert conditions in which this irrigation system is intended for use. Experimental results show that isothermal vapour flows can significantly affect the performance of such irrigation systems due to the rapid transport of water through the soil via the vapour phase. When the irrigation pipe was buried at a depth of 10cm a vapour flow from the soil surface was observed in less than 2 hours. These flows therefore affect the loss of mass into the atmosphere and thus must be considered when evaluating the availability of water for the irrigated crop. The experiments also provide a rare opportunity to observe isothermal vapour flows initiating from a subsurface source. Such experiments allow the significance of these flows to be quantified and potentially applied to other areas of arid zone hydrology.

  18. Patterns of migration in Tanzania.

    OpenAIRE

    Bernstein, H

    1981-01-01

    ILO pub-wep pub. Working paper identifying internal migration patterns and employment implications in Tanzania - discusses reasons for migration, types (seasonal workers, permanent, etc.), Migration within rural areas or urban areas, rural migration, land settlement trends, etc. References.)

  19. Can inter-cultivar variation in caesium and strontium uptake reduce contamination of forage grasses? - Can inter-cultivar variation in caesium and strontium accumulation by forage grasses be used to reduce contamination of cows' milk in radiologically contaminated areas?

    Energy Technology Data Exchange (ETDEWEB)

    Penrose, B. [NERC Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Lancaster, LA1 4AP (United Kingdom); School of Biosciences, University of Nottingham, Sutton Bonington Campus, Leicestershire, LE12 5RD (United Kingdom); Beresford, N. [NERC Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Lancaster, LA1 4AP (United Kingdom); Broadley, M.; Crout, N.M.J.; King, J.; Young, S. [School of Biosciences, University of Nottingham, Sutton Bonington Campus, Leicestershire, LE12 5RD (United Kingdom); Lovatt, A. [Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, Gogerddan, Aberystwyth, Ceredigion, SY23 3E E (United Kingdom); Thomson, R. [Science and Advice for Scottish Agriculture (SASA), Roddinglaw Road, Edinburgh, EH12 9FJ (United Kingdom)

    2014-07-01

    Radiocaesium and radiostrontium primarily enter the food chain via plant root uptake, including indirectly via animal fodders. Inter-species variation in caesium and strontium accumulation in plants has previously been reported to be over two orders of magnitude. This variation could be exploited to select crops with relatively low uptake to reduce transfer of these radionuclides to consumers in contaminated areas. Exploiting intra-species (i.e. inter-cultivar) variation in caesium and strontium uptake has not yet been evaluated as a remediation strategy as sufficient data have not been available. As cows' milk has been one of the main contributors to human dose following the Chernobyl and Mayak accidents, we have chosen to focus on elucidating the extent and nature of inter-cultivar variation in caesium and strontium uptake in forage grasses. A total of 412 cultivars from four species of forage grass; perennial ryegrass (Lolium perenne; 284 cultivars), Italian ryegrass (Lolium multiflorum; 17 cultivars), hybrid ryegrass (Lolium hybridum; 101 cultivars) and tall fescue (Festuca arundinacea; 10 cultivars) were sampled from 20 sets of experimental plots in Aberystwyth (Wales, UK) and Edinburgh (Scotland, UK). Fifty-nine cultivars were grown in both locations. At least three replicates of the same cultivar were grown in each set of plots. Vegetation samples from 2208 plots were collected both in spring 2013 (May-June) and summer 2013 (August-September). The samples were oven-dried and milled then analysed for elemental composition using inductively coupled plasma mass spectrometry (ICP-MS). Stable caesium and strontium were measured as a proxy measurement for radiocaesium and radiostrontium concentrations. Concentrations of chemical analogues of caesium and strontium (potassium and calcium) and a number of other elements were measured. Soil samples from the experimental plots were also collected, dried, milled and analysed using ICP-MS. This paper will present

  20. RBE values for colo-rectal injury after caesium 137 gamma-ray and neutron irradiation. 1. Single doses

    Energy Technology Data Exchange (ETDEWEB)

    Terry, N.H.A.; Denekamp, J.; Maughan, R.L. (Mount Vernon Hospital, Northwood (UK). Gray Lab.)

    1983-04-01

    Colo-rectal damage in mice has been assessed after caesium ..gamma.. irradiation and 3 MeV neutrons given as single doses. Several assays were used, including body weight changes, faecal deformity and lethality. Dose response curves were constructed for each assay at times ranging from 10 days to 16 months after irradiation. An initial loss of weight at 10-20 days was presumably related to epithelial denudation, but a dose-dependent weight reduction (compared with controls) persisted over the animals' life span. Mice died progressively after localised pelvic ..gamma.. irradiation; there was no sharp demarcation between an early and late phase of lethal injury. Death resulted from intestinal stricture or stenosis. The time course for lethality was qualitatively different after neutron irradiation, with little progression of damage between 5 and 11 months. Faecal deformity was detectable as a higher proportion of small pellets when the rectum became constricted by fibrosis. No significant faecal deformity was observed before 6 months after which time dose response curves could be obtained. The RBE for early damage (assessed at 1-3 months) was 2.2-2.7, falling to 1.7-1.9 for late damage (determined at 10-15 months) over the range of neutron doses of 7.5-12 Gy.

  1. [Radiotherapy for carcinoma of the cervix by intermittent sessions with deferred loading using Cobalt 60 or Caesium 137 (author's transl)].

    Science.gov (United States)

    Swyngedauw, J

    1976-11-01

    Fractioning in gynaecological radiotherapy is a tolerance factor which may usefully be exploited in after loading. The advantage of fractioning is that it makes it possible to considerably increase the output of the projection apparatus (Curietron) and to avoid protection of the rooms : the patient retains the applicator in situ during the hospital stay and her bed is simply taken into the protected application room. With a source of 1 to 1.5 curie of cobalt, the author proposes twice-daily sessions of around ten minutes for ten days. Treatment may easily be given in the cobaltotherapy chamber. Using Caesium, it is necessary to protect only one room with a virtually two-fold increase in output since 10 to 12 hour treatments, either by day or by night, may be given. This very supple schedule makes it possible to modify dose and tolerance in relation to clinical conditions and the method of treatment (combined radiotherapy and surgery or radiotherapy alone). As far as axial vaginal source introducer is concerned, it is of prove, effectiveness as well as being easy to use. After describing the applicator, the source-carrier and the isodoses, the authors reviews the different methods of application, relying upon two previous studies of the influence of fractioning and protraction on tolerance (J. SWYNGEDAUW, 1975 and 1976).

  2. Determining soil redistribution in Dian Lake catchment by combined use of caesium-137 and selected chemical properties

    Institute of Scientific and Technical Information of China (English)

    Zhang Mingli; Yang Hao; Xu Congan; Wang Yihong

    2009-01-01

    Recent development in the use of the environmental radionuclide caesium-137 for documenting rates and patterns of soil redistribution on the cultivated or uncultivated land and estimating rates of sediment deposition on floodplains represents an important advance that overcomes many of the limitations' of the conventional techniques commonly applied in such investigations.A study on soil redistribution (including soil erosion and deposition) was carried out in the Dian Lake catchment,Yunnan Province,using 137Cs and selected chemical properties.The average soil erosion rate was 1,280.2 t km-2yr-1.Soil erosion rate occurring on different parts of the slope was significantly different on different parts of the slope,increasing from the top,the bottom to the middle slope.The average soil erosion rate is also different with the land use type and that of the cultivated land (1,672.8 t km-2 yr-1) is higher than of the uncultivated land (1,161.2 t km-2yr-1).The result shows that landform,slope gradient and land use type are key factors that influence the size of soil erosion.In addition,we also find the SOC and TN contents and amount of the soil erosion to be correlated in the soil.With the soil erosion occurring,there are land degradation and the local eco-environmental problems,such as water eutrophication in Dian Lake

  3. Change of the radionuclide content of landscapes contamination in the small catchment at the Bryansk-Belarus caesium spot

    International Nuclear Information System (INIS)

    The results of the joint Russian-Belarus RFBR-BelRFBR project no. 02-05-81011 will be shown. Information on the spatial redistribution of 137Cs within small catchment and through the connected landscapes is an important background for estimating consequences of the Chernobyl contamination. 137Cs can be used as a tracer for study the direction and intensity of geo-chemical processes in landscapes of small catchment. The experimental data on the modern radionuclide content of soil and plant contamination have been received at the expeditions of 2000-2004 in the regions situated on distances 50, 150 and 250 km from the Chernobyl NPP on territories of Belarus and Russia. Some small catchment in the Dnieper basin have been studied (Braginka, Sozh and Moskovka rivers). The content of 137Cs, 90Sr, 239+240Pu and 241Am in soils will be presented. The modern variability of contamination levels in each of connected landscapes will be compared with the variability estimated immediately after the Chernobyl accident. The high spatial fixation of Caesium spots by the Polessye landscapes will be shown. (author)

  4. Spatial distribution of caesium-137 in soil cover of background terrestrial ecosystems, Central European Russia

    Energy Technology Data Exchange (ETDEWEB)

    Paramonova, Tatiana A. [Radioecology and Ecotoxicology Department of Soil Science Faculty, Moscow State Lomonosov University, 119234 Moscow (Russian Federation); Shamshurina, Evgenia N. [Laboratory of soil erosion and fluvial processes of Geography Faculty, Moscow State Lomonosov University, 119234 Moscow (Russian Federation)

    2014-07-01

    ¹³⁷Cs - the main long-living anthropogenic radionuclide - arrived in mass at Russian terrestrial ecosystems after nuclear tests in the atmosphere in 1960-yy. and after Chernobyl accident in 1986 y., but in spite of a long period since these events soil cover contamination by ¹³⁷Cs is considered as extremely resistant due to its firmly fixation by soil solid matter and a long half-life of the radionuclide. Wide-scale investigation in maximal diversity of natural, semi-natural and anthropogenic landscapes of Central European Russia (more than 400 soils samples from Vologda, Yaroslavl, Ivanovo, Tver regions which are representative for the southern taiga zone) demonstrates that modern average specific activity of ¹³⁷Cs in the upper 15-cm layer of soil is 11±3 Bq/kg (contamination density 0.05±0.01 Ci/km²), that is fully ecologically acceptable. It is important that the average concentrations of ¹³⁷Cs in the soil cover of individual regions are close to each other. The most likely these average values are approximate assessment of background radioactive contamination of soils in central European Russia outside of the immediate Chernobyl trace. At the same time approximately 3% of soils are characterized by elevated ¹³⁷Cs content - 62-98 Bq/kg (0.24-0.43 Ci/km²), that indicates the presence of low radioactive spots on the territory and may be considered as local Chernobyl fallout. All of them attribute with forest soils which are commonly characterized by considerably more high accumulation of ¹³⁷Cs (18±5 Bq/kg, 0.06±0.01 Ci/km²) due to advanced absorbing surface of trees. Agricultural lands (plagued or under meadows) and soils of industrial plots with scarce vegetation contain only 6±2 Bq/kg (0.03±0.01 Ci/km²) of ¹³⁷Cs. About 84-92% of ¹³⁷Cs are concentrated in the upper 15-cm layer of natural soils or in Ap horizon of plagued soils, thus vertical migration of radionuclide is very slow in spite of ~30 years after Chernobyl

  5. The accretion of migrating giant planets

    CERN Document Server

    Dürmann, Christoph

    2016-01-01

    Most studies concerning the growth and evolution of massive planets focus either on their accretion or their migration only. In this work we study both processes concurrently to investigate how they might mutually affect each other. We modeled a 2-dimensional disk with a steady accretion flow onto the central star and embed a Jupiter mass planet at 5.2 au. The disk is locally isothermal and viscosity is modeled using a constant $\\alpha$. The planet is held on a fixed orbit for a few hundred orbits to allow the disk to adapt and carve a gap. After this period, the planet is released and free to move according to the gravitational interaction with the gas disk. The mass accretion onto the planet is modeled by removing a fraction of gas from the inner Hill sphere, and the removed mass and momentum can be added to the planet. Our results show that a fast migrating planet is able to accrete more gas than a slower migrating planet. Utilizing a tracer fluid we analyzed the origin of the accreted gas which comes pred...

  6. Isothermal Dilatometric Study of Sintering in Kaolin

    Science.gov (United States)

    Ondruška, Ján; Trník, Anton; Keppert, Martin; Medved', Igor; Vozár, Libor

    2014-10-01

    Solid-state sintering for kaolin samples was studied by dilatometric measurements in the isothermal regime in the temperature range from 600 °C to 1100 °C. The relative expansion was measured for a period of 10h. For the temperatures up to 850 °C, we observed only a small shrinkage (less than 0.5 %), most of which took place within the first 3h of the measurements. For the temperatures above 850 °C, a significant shrinkage occurred for the whole measured time interval and reached up to 2.7 %. Anomalous behavior—a decrease in the shrinkage with the temperature—was observed in the range from 700 °C to 850 °C. The dilatometric measurements are supplemented by porosity distribution measurements. The standard spherical-grains microscopic model was applied to determine that for the initial stages of the sintering process, grain boundary diffusion was the dominant mechanism at lower temperatures (600 °C to 850 °C), whereas lattice diffusion was dominant at higher temperatures (900 °C, 1050 °C, and 1100 °C).

  7. Unemployment, migration, and growth

    OpenAIRE

    Valerie R. Bencivenga; Bruce D. Smith

    1995-01-01

    Economic development is typically accompanied by a very pronounced migration of labor from rural to urban employment. This migration, in turn, is often associated with large scale urban underemployment. Both factors appear to play a very prominent role in the process of development. We consider a model in which rural-urban migration and urban underemployment are integrated into an otherwise conventional neoclassical growth model. Unemployment arises not from any exogenous rigidities, but from...

  8. Many Faces of Migrations

    OpenAIRE

    Milica Antić Gaber; Marko Krevs

    2013-01-01

    Temporary or permanent, local or international, voluntary or forced, legal or illegal, registered or unregistered migrations of individuals, whole communities or individual groups are an important factor in constructing and modifying (modern) societies. The extent of international migrations is truly immense. At the time of the preparation of this publication more than 200 million people have been involved in migrations in a single year according to the United Nations. Furthermore, three time...

  9. TYPES OF MODERN MIGRATION

    OpenAIRE

    KAITMAZOVA KARINA RUSLANOVNA; CABERTI ALINA NODAROVNA

    2016-01-01

    The detailed classification of migration is analyzed, also a conclusion is drawn according to the fact that migration contributes to the development of the population of countries and regions, appearing to be a driving force and an important factor of globalization in the XXI century. Russia, also as other countries, strongly depends on migration: future of the Russian Federation depends on the fact how socially-spiritual community of Russian people will change, and also culture and values of...

  10. Malaysia and forced migration

    OpenAIRE

    Arzura Idris

    2012-01-01

    This paper analyzes the phenomenon of “forced migration” in Malaysia. It examines the nature of forced migration, the challenges faced by Malaysia, the policy responses and their impact on the country and upon the forced migrants. It considers forced migration as an event hosting multifaceted issues related and relevant to forced migrants and suggests that Malaysia has been preoccupied with the issue of forced migration movements. This is largely seen in various responses invoked from Malaysi...

  11. Regional Redistribution and Migration

    DEFF Research Database (Denmark)

    Manasse, Paolo; Schultz, Christian

    We study a model with free migration between a rich and a poor region. Since there is congestion, the rich region has an incentive to give the poor region a transfer in order to reduce immigration. Faced with free migration, the rich region voluntarily chooses a transfer, which turns out...... to be equal to that a social planner would choose. Provided migration occurs in equilibrium, this conclusion holds even in the presence of moderate mobility costs. However, large migration costs will lead to suboptimal transfers in the market solution...

  12. Caesium 137: Properties and biological effects resulting of an internal contamination;Cesium 137: proprietes et effets biologiques apres contamination interne

    Energy Technology Data Exchange (ETDEWEB)

    Lestaevel, P.; Racine, R.; Bensoussan, H.; Rouas, C.; Gueguen, Y.; Dublineau, I.; Bertho, J.M.; Gourmelon, P.; Jourdain, J.R.; Souidi, M. [Institut de Radioprotection et de Surete Nucleaire, IRSN, laboratoire de radiotoxicologie experimentale, direction de la radioprotection de l' homme, 92 - Fontenay-aux-Roses (France)

    2010-02-15

    Caesium-137 ({sup 137}Cs) is a radionuclide present in the environment mainly as the result of the atmospheric nuclear weapons testing and accidents arising in nuclear power plants like the Chernobyl accident in 1986. Nowadays, the health consequences resulting from a chronic exposure to this radionuclide remain unknown. After absorption, the caesium is distributed relatively homogeneously within the body, with a more important load in children than in adults. The toxicity of {sup 137}Cs is mainly due to its radiological properties. A high dose of {sup 137}Cs is responsible for a medullar dystrophy, disorders of the reproductive function, and effects on liver and renal functions. Disorders of bone mineralization and brain damages were also described in human beings. At lowest dose, {sup 137}Cs induces disturbances of wakefulness-sleep cycle, but not accompanied with behavioural disorders. The cardiovascular system was also perturbed. Biological effects of {sup 137}Cs on the metabolisms of the vitamin D, cholesterol and steroid hormones were described, but do not lead to clinical symptoms. In human beings, {sup 137}Cs leads to an immune deficiency, congenital and foetal deformations, an increased of thyroid cancer, as well as neurological disorders. It seems that children are more sensitive to the toxic effects of caesium than the adults. At present, the only effective treatment for the decorporation of the ingested {sup 137}Cs is the Prussian Blue (Radiogardase). The use of pectin to de-corporate the ingested {sup 137}Cs, in children notably, is sometimes proposed, but its administration still remains an open question. To conclude, the available scientific data suggest that {sup 137}Cs could affect a number of physiological and metabolic functions and consequently, could participate in the health risks associated to the presence of other contaminants in the environment. (authors)

  13. Contribution to the use in analysis of ammonium phosphomolybdate- separation of radio-caesium in solution; Contribution a l'utilisation analytique du phosphomolybdate d'ammonium - separation du radiocesium en solution

    Energy Technology Data Exchange (ETDEWEB)

    Scheidhauer, J.; Chabidon, M.; Ordinaire, L. [Commissariat a l' Energie Atomique, Centre de Production de Plutonium, Marcoule (France). Centre d' Etudes Nucleaires

    1964-07-01

    The use in analysis of ammonium phosphomolybdate has been studied for the separation of barium from caesium 137. The cases have been studied of small and medium-sized volumes, and of large volumes of about 100 litres. (authors) [French] L'utilisation analytique du phosphomolybdate d'ammonium est etudiee pour la separation du 137 caesium-baryum. Les cas des petits et moyens volumes et des grands volumes de l'ordre de 100 litres sont abordes successivement. (auteurs)

  14. Desorption behaviour of artificial radionuclides sorbed on to estuarine silt: (1) Caesium-137 and ruthenium-106, (2) Zirconium-95 and niobium-95

    International Nuclear Information System (INIS)

    A series of desorption tests was carried out on silt contaminated with radioactive waste from the Sellafield (formerly Windscale) fuel reprocessing plant. The aim of the desorptions was to attempt to elucidate the chemical form in which certain radionuclides were held by the sediments. The first part of the study indicated that caesium was held, in the main, on inaccessible ion-exchange sites and that ruthenium appeared to be partially adsorbed and partially held by anion-exchange sites. The second part of the study indicated that zirconium and niobium were sorbed chemically or physically in the form of complex hydrous oxides. (author)

  15. Poly[(μ6-4-amino-3,5,6-trichloro­pyridine-2-carboxyl­ato)aqua­caesium

    OpenAIRE

    Smith, Graham

    2012-01-01

    In the structure of the title complex, [Cs(C6H2Cl3N2O2)(H2O)] n , the caesium salt of the commercial herbicide picloram, the Cs+ cation lies on a crystallographic mirror plane, which also contains the coordinating water mol­ecule and all non-H atoms of the 4-amino-3,5,6-trichloro­picolinate anion except the carboxyl­ate O-atom donors. The irregular CsCl4O5 coordination polyhedron comprises chlorine donors from the ortho-related ring substituents of the picloramate ligand in a bidentate chelat...

  16. Spectral anomalies of the effect of light-induced drift of caesium atoms caused by the velocity dependence of transport collision frequencies

    International Nuclear Information System (INIS)

    The spectral features of the light-induced drift (LID) velocity of caesium atoms in inert buffer gases are studied theoretically. A strong temperature dependence of the spectral LID line shape of Cs atoms in Ar or Kr atmosphere in the vicinity of T ∼ 1000 K is predicted. It is shown that the anomalous LID of Cs atoms in binary buffer mixtures of two different inert gases can be observed at virtually any (including ambient) temperature, depending on the content of the components in these mixtures. The results obtained make it possible to precisely test the interatomic interaction potentials in the experiments on the anomalous LID. (quantum optics)

  17. Phase field modeling of dendritic coarsening during isothermal

    Directory of Open Access Journals (Sweden)

    Zhang Yutuo

    2011-08-01

    Full Text Available Dendritic coarsening in Al-2mol%Si alloy during isothermal solidification at 880K was investigated by phase field modeling. Three coarsening mechanisms operate in the alloy: (a melting of small dendrite arms; (b coalescence of dendrites near the tips leading to the entrapment of liquid droplets; (c smoothing of dendrites. Dendrite melting is found to be dominant in the stage of dendritic growth, whereas coalescence of dendrites and smoothing of dendrites are dominant during isothermal holding. The simulated results provide a better understanding of dendrite coarsening during isothermal solidification.

  18. Modeling and Prediction of Soil Water Vapor Sorption Isotherms

    DEFF Research Database (Denmark)

    Arthur, Emmanuel; Tuller, Markus; Moldrup, Per;

    2015-01-01

    Soil water vapor sorption isotherms describe the relationship between water activity (aw) and moisture content along adsorption and desorption paths. The isotherms are important for modeling numerous soil processes and are also used to estimate several soil (specific surface area, clay content.......93) for a wide range of soils; and (ii) develop and test regression models for estimating the isotherms from clay content. Preliminary results show reasonable fits of the majority of the investigated empirical and theoretical models to the measured data although some models were not capable to fit both sorption...

  19. Total Correlation Function Integrals and Isothermal Compressibilities from Molecular Simulations

    DEFF Research Database (Denmark)

    Wedberg, Rasmus; Peters, Günther H.j.; Abildskov, Jens

    2008-01-01

    Generation of thermodynamic data, here compressed liquid density and isothermal compressibility data, using molecular dynamics simulations is investigated. Five normal alkane systems are simulated at three different state points. We compare two main approaches to isothermal compressibilities: (1...... approximately the same amount of time. This suggests that computation of total correlation function integrals is a route to isothermal compressibility, as accurate and fast as well-established benchmark techniques. A crucial step is the integration of the radial distribution function. To obtain sensible results...

  20. Isothermal sintering kinetics of UOsub(2+x)

    International Nuclear Information System (INIS)

    The isothermal sintering kinetics of UOsub(2+x) were studied by measuring the densification rate in an optical dilatometer developed for this purpose. The sintering was conducted at constant temperature by using thin UOsub(2+x) compacts with a constant nonstoichiometry. The oxygen partial pressure in the sintering atmosphere was continuously measured by a stabilized ZrO2 solid electrolyte cell, particular attention being paid to the starting conditions of the ideal sintering. An empirical densification rate equation that describes the sintering kinetics within a large range was verified: density range 52 - 83% of the theoretical density, temperature range 1000 degC - 1550 degC, nonstoichiometry range Psub(O2)=10sup(-15.3)-10sup(-8.4)Pa, at 1100 degC, sintering time 12 s - 281 h. The effect of temperature on the sintering rate was compatible with the values reported in the literature for the effect of temperature on the uranium self-diffusion, the determined activation energy being 432 +- 13 kJ/mole. It was also noted that the uranium self-diffusion is suitable as the dominating factor in the sintering kinetics of UOsub(2+x). The rise in temperature from 1000 degC to 1550 degC increased the densification rate constant k 40-fold, and the change in oxygen partial pressure from Psub(O2)=10sup(-15.3) to Psub(O2)=10sup(-8.4) Pa at 1100 degC 4-fold. At 800 degC and at composition UOsub(2.1) a sintering rate was measured that corresponds to the sintering rate of a stoichiometric compact at 1320 degC. With the method applied in the present study and the verified empirical equation, the effect of the various factors on the sintering of the uranium dioxide compacts used as fuel elements can be studied accurately. (author)

  1. Isothermal reduction of titanomagnetite concentrates containing coal

    Institute of Scientific and Technical Information of China (English)

    Tu Hu; Xue-wei Lü; Chen-guang Bai; Gui-bao Qiu

    2014-01-01

    The isothermal reduction of the Panzhihua titanomagnetite concentrates (PTC) briquette containing coal under argon atmosphere was investigated by thermogravimetry in an electric resistance furnace within the temperature range of 1250-1350°C. The samples reduced in argon at 1350°C for different time were examined by X-ray diffraction (XRD) analysis. Model-fitting and model-free methods were used to evaluate the apparent activation energy of the reduction reaction. It is found that the reduction rate is very fast at the early stage, and then, at a later stage, the reduction rate becomes slow and decreases gradually to the end of the reduction. It is also observed that the reduction of PTC by coal depends greatly on the temperature. At high temperatures, the reduction degree reaches high values faster and the final value achieved is higher than at low temperatures. The final phase composition of the reduced PTC-coal briquette consists in iron and fer-rous-pseudobrookite (FeTi2O5), while Fe2.75Ti0.25O4, Fe2.5Ti0.5O4, Fe2.25Ti0.75O4, ilmenite (FeTiO3) and wustite (FeO) are intermediate products. The reaction rate is controlled by the phase boundary reaction for reduction degree less than 0.2 with an apparent activation energy of about 68 kJ·mol-1 and by three-dimensional diffusion for reduction degree greater than 0.75 with an apparent activation energy of about 134 kJ·mol-1. For the reduction degree in the range of 0.2-0.75, the reaction rate is under mixed control, and the activation energy increases with the increase of the reduction degree.

  2. A new approach to predicting environmental transfer of radionuclides to wildlife: A demonstration for freshwater fish and caesium

    International Nuclear Information System (INIS)

    The application of the concentration ratio (CR) to predict radionuclide activity concentrations in wildlife from those in soil or water has become the widely accepted approach for environmental assessments. Recently both the ICRP and IAEA have produced compilations of CR values for application in environmental assessment. However, the CR approach has many limitations, most notably, that the transfer of most radionuclides is largely determined by site-specific factors (e.g. water or soil chemistry). Furthermore, there are few, if any, CR values for many radionuclide-organism combinations. In this paper, we propose an alternative approach and, as an example, demonstrate and test this for caesium and freshwater fish. Using a Residual Maximum Likelihood (REML) mixed-model regression we analysed a dataset comprising 597 entries for 53 freshwater fish species from 67 sites. The REML analysis generated a mean value for each species on a common scale after REML adjustment taking account of the effect of the inter-site variation. Using an independent dataset, we subsequently test the hypothesis that the REML model outputs can be used to predict radionuclide, in this case radiocaesium, activity concentrations in unknown species from the results of a species which has been sampled at a specific site. The outputs of the REML analysis accurately predicted 137Cs activity concentrations in different species of fish from 27 Finnish lakes; these data had not been used in our initial analyses. We recommend that this alternative approach be further investigated for other radionuclides and ecosystems. - Highlights: • An alternative approach to estimating radionuclide transfer to wildlife is presented. • Analysed a dataset comprising 53 freshwater fish species collected from 67 sites. • Residual Maximum Likelihood mixed model regression is used. • Model output takes account of the effect of inter-site variation. • Successfully predicted 137Cs concentrations in different fish

  3. International Migration of Couples

    DEFF Research Database (Denmark)

    Munk, Martin D.; Junge, Martin; Poutvaara, Panu

    2016-01-01

    We develop a theoretical model regarding the migration of dual-earner couples and test it in the context of international migration. Our model predicts that the probability that a couple emigrates increases with the income of the primary earner, whereas the income of the secondary earner may affect...

  4. Samtidskunst og migration

    DEFF Research Database (Denmark)

    Petersen, Anne Ring

    2010-01-01

    "Samtidskunst og migration. En oversigt over faglitteraturen" er en forskningsoversigt der gør status over hvad der hidtil er skrevet inden for det kunsthistoriske område om vor tids billedkunst og migration som politisk, socialt og kulturelt fænomen, primært i forbindelse med immigration til...

  5. International Migration of Couples

    DEFF Research Database (Denmark)

    Junge, Martin; Munk, Martin D.; Poutvaara, Panu

    2016-01-01

    Migrant self-selection is important to both origin and destination countries. We develop a theoretical model regarding the migration of dual-earner couples and test it in the context of international migration, using population-wide administrative data from Denmark. Our model predicts...

  6. Migration in Burkina Faso

    NARCIS (Netherlands)

    Wouterse, F.S.

    2007-01-01

    Migration plays an important role in development and as a strategy for poverty reduction. A recent World Bank investigation finds a significant positive relationship between international migration and poverty reduction at the country level (Adams and Page 2003). Burkina Faso, whose conditions for a

  7. Migrating Art History

    DEFF Research Database (Denmark)

    Ørum, Tania

    2012-01-01

    Review of Hiroko Ikegami, The Great Migrator. Robert Rauschenberg and the Global Rise of American Art. Cambridge Mass., The MIT Press, 2010. 277 pages. ISBN 978-0-262-01425-0.......Review of Hiroko Ikegami, The Great Migrator. Robert Rauschenberg and the Global Rise of American Art. Cambridge Mass., The MIT Press, 2010. 277 pages. ISBN 978-0-262-01425-0....

  8. Malaysia and forced migration

    Directory of Open Access Journals (Sweden)

    Arzura Idris

    2012-06-01

    Full Text Available This paper analyzes the phenomenon of “forced migration” in Malaysia. It examines the nature of forced migration, the challenges faced by Malaysia, the policy responses and their impact on the country and upon the forced migrants. It considers forced migration as an event hosting multifaceted issues related and relevant to forced migrants and suggests that Malaysia has been preoccupied with the issue of forced migration movements. This is largely seen in various responses invoked from Malaysia due to “south-south forced migration movements.” These responses are, however, inadequate in terms of commitment to the international refugee regime. While Malaysia did respond to economic and migration challenges, the paper asserts that such efforts are futile if she ignores issues critical to forced migrants.

  9. Migration of health workers.

    Science.gov (United States)

    Buchan, James

    2008-01-01

    The discussion and debate stimulated by these papers focused across a range of issues but there were four main areas of questioning: "measuring" and monitoring migration (issues related to comparability, completeness and accuracy of data sets on human resources); the impact of migration of health workers on health systems; the motivations of individual health workers to migrate (the "push" and "pull" factors) and the effect of policies designed either to reduce migration (e.g "self ufficiency") or to stimulate it (e.g active international recruitment). It was recognised that there was a critical need to examine migratory flows within the broader context of all health care labour market dynamics within a country, that increasing migration of health workers was an inevitable consequence of globalisation, and that there was a critical need to improve monitoring so as to better inform policy formulation and policy testing in this area. PMID:18561695

  10. World Migration Degree Global migration flows in directed networks

    CERN Document Server

    Porat, Idan

    2015-01-01

    In this article we analyze the global flow of migrants from 206 source countries to 145 destination countries (2006-2010) and focus on the differences in the migration network pattern between destination and source counters as represented by its degree and weight distribution. Degree represents the connectivity of a country to the global migration network, and plays an important role in defining migration processes and characteristics. Global analysis of migration degree distribution offers a strong potential contribution to understanding of migration as a global phenomenon. In regard to immigration, we found that it is possible to classify destination countries into three classes: global migration hubs with high connectivity and high migration rate; local migration hubs with low connectivity and high migration rate; and local migration hubs with opposite strategy of high connectivity and low migration rate. The different migration strategies of destination countries are emerging from similar and homogenies p...

  11. The density variance - Mach number relation in isothermal and non-isothermal adiabatic turbulence

    CERN Document Server

    Nolan, Chris A; Sutherland, Ralph S

    2015-01-01

    The density variance - Mach number relation of the turbulent interstellar medium is relevant for theoretical models of the star formation rate, efficiency, and the initial mass function of stars. Here we use high-resolution hydrodynamical simulations with grid resolutions of up to 1024^3 cells to model compressible turbulence in a regime similar to the observed interstellar medium. We use Fyris Alpha, a shock-capturing code employing a high-order Godunov scheme to track large density variations induced by shocks. We investigate the robustness of the standard relation between the logarithmic density variance (sigma_s^2) and the sonic Mach number (M) of isothermal interstellar turbulence, in the non-isothermal regime. Specifically, we test ideal gases with diatomic molecular (gamma = 7/5) and monatomic (gamma = 5/3) adiabatic indices. A periodic cube of gas is stirred with purely solenoidal forcing at low wavenumbers, leading to a fully-developed turbulent medium. We find that as the gas heats in adiabatic comp...

  12. Comparison of multifractal parameters form adsorption isotherms, desorption isotherms and mercury intrusion curves

    Science.gov (United States)

    Paz-Ferreiro, Jorge; Mon, Rodolfo; Vidal Vázquez, Eva

    2013-04-01

    The soil pore space is composed of a continuum of pores extremely variable in size, which range from equivalent diameter sizes smaller than nanometers to an upper limit of the order of centimeters. So, it is quite typical for soil pore space to display a size range of more than a factor of 106 in scale. Nitrogen sorption and mercury injection provide pores size distributions in the range from about 0.1 to 0.001 μm and 150 to 0.005 μm, respectively. The aims of this study were to evaluate the scaling properties of nitrogen adsorption isotherms (NAI), nitrogen desorption isotherms (NDI) and mercury intrusion porosimetry (MIP) curves of agricultural soils from "La Pampa húmeda", in the north of Buenos Aires and south of Santa Fé provinces, Argentina. Both NAIs, NDIs and MIPs exhibited multifractal behavior but its scaling properties were different so that the multifractality index, assessed by the width of the generalized dimension and the singularity spectra ranked as follows: NAI > NDI > MIP. Also, parameterization by the Hurst exponent indicates NAIs were less persistent than NDIs and in turn, these were less persistent than MIPs. The multfractal approach was useful to characterize the heterogeneity of various domains of the soil nano- micro- and mesopore system at the scale of small aggregates.

  13. On marriage and migration.

    Science.gov (United States)

    Stark, O

    1988-09-01

    Marriage, migration, and related phenomena such as marital stability, fertility, and investment in human capital may be better explained by studying marriage and migration jointly. This paper examines the role of migration in obtaining joint labor market and marriage market equilibrium. When broadly interpreted, marriage and migration share a number of common features. Both involve search and its resolution (pairing of mates in the former and matching of labor and firms in the latter). In both cases, success in finding a partner is sensitive to the availability of partners and to the distribution of their endowments and traits. Almost always, and along with separation and divorce, marriage mandates spatial relocation which may translate into migration. Both involve a movement that is associated with adjustment costs from 1 state into another. The decisions to enter marriage and undertake employment or the decisions to divorce and quit a job depend on exogenous parameters, some of which are determined by the marriage market and the labor market. Since both marriage and divorce take place in the context of broadly defined markets, they may and often are analyzed applying market concepts, theorems, and solutions. Yet the authors could not pinpoint 1 single, systematic attempt that checks through the interactions between marriage and migration, so this paper attempts to rectify this state of research. Essentially, this paper 1) discusses individual decision making pending possible migration prior to or following marriage, 2) examines whether it is easier for a married couple or a single person to migrate, and 3) considers whether marriage dissolution could cause migration when marriage is the only reason that has kept a spouse from moving. This integrated research agenda for both marriage and migration can delineate interesting new implications to examine.

  14. Improved Isotherm Data for Adsorption of Methane on Activated Carbons

    KAUST Repository

    Loh, Wai Soong

    2010-08-12

    This article presents the adsorption isotherms of methane onto two different types of activated carbons, namely, Maxsorb III and ACF (A-20) at temperatures from (5 to 75) °C and pressures up to 2.5 MPa. The volumetric technique has been employed to measure the adsorption isotherms. The experimental results presented herein demonstrate the improved accuracy of the uptake values compared with previous measurement techniques for similar adsorbate-adsorbent combinations. The results are analyzed with various adsorption isotherm models. The heat of adsorption, which is concentration and temperature dependent, has been calculated from the measured isotherm data. Henry\\'s law coefficients for these adsorbent-methane pairs are also evaluated at various temperatures. © 2010 American Chemical Society.

  15. The Calculation of Adsorption Isotherms from Chromatographic Peak Shapes

    Science.gov (United States)

    Neumann, M. G.

    1976-01-01

    Discusses the relationship between adsorption isotherms and elution peak shapes in gas chromatography, and describes a laboratory experiment which involves the adsorption of hexane, cyclohexane, and benzene on alumina at different temperatures. (MLH)

  16. Refrigeration Carnot-type cycle based on isothermal vapour compression

    Energy Technology Data Exchange (ETDEWEB)

    Meunier, F. [Laboratoire du Froid EA 21, Cnam-IFFI, 292 rue Saint-Martin (France)

    2006-01-01

    A refrigeration Carnot-type cycle based on isothermal compression and two reversible expansions is proposed. Although ideal, this cycle is close to a realistic one which could be designed with existing hardware. (author)

  17. ISOTHERMAL AND THERMOMECHANICAL FATIGUE OF A NICKEL-BASE SUPERALLOY

    OpenAIRE

    Carlos Carvalho Engler-Pinto Júnior; Dirceu Spinelli

    2014-01-01

    Thermal gradients arising during transient regimes of start-up and shutdown operations produce a complex thermal and mechanical fatigue loading which limits the life of turbine blades and other engine components operating at high temperatures. More accurate and reliable assessment under non-isothermal fatigue becomes therefore mandatory. This paper investigates the nickel base superalloy CM 247LC-DS under isothermal low cycle fatigue (LCF) and thermomechanical fatigue (TMF). Test ...

  18. A Study of Isothermal Curing of PMI Using DMA

    OpenAIRE

    Jing Zhang; Rui Ye; Jun Zou; Jijun Tang; Hongliang Wang

    2015-01-01

    The isothermal curing of polymethacrylimide (PMI) is studied through the use of dynamic mechanical analysis (DMA). Based on the growth rate of measured dynamic mechanical property, the relative conversion is defined to investigate the evolution of storage modulus E′ at different curing temperatures. Hsich’s nonequilibrium thermodynamic fluctuation theory, Avrami equation, and isoconversional methods are used to analyze isothermal cure kinetics of PMI. The results show that there are different...

  19. Non-isothermal Crystallization Kinetics of Poly(L-lactide)

    OpenAIRE

    Li, Suming

    2010-01-01

    International audience The non-isothermal crystallization kinetics of poly(L-lactide) (PLLA) in comparison with a polylactide stereocopolymer (PLA98) containing 98% L-lactyl and 2% D-lactyl units were investigated using differential scanning calorimetry to examine the effect of the configurational structure. Avrami, Ozawa and Liu models were applied to describe the crystallization process. The Avrami analysis exhibited two stages in non-isothermal crystallization, while the Ozawa and Liu m...

  20. Isothermal Calorimetry for Biological Applications in Food Science and Technology

    OpenAIRE

    Wadsö, Lars; Gomez, Federico

    2009-01-01

    All physical, chemical and biological processes produce heat and isothermal calorimetry is a general measurement technique to study all kinds of processes by the heat they produce. This paper gives several examples of studies of biological processes in the food area using isothermal calorimetry. It is for example shown how different unit operations influence respiration of vegetable tissue, how the kinetics of a fermentation process can be studied, and how spoilage processes can be followed f...

  1. On The Strategies Towards Isothermal Gas Compression And Expansion

    OpenAIRE

    Heidari, Mahbod; Lemofouet, Sylvain; Rufer, Alfred

    2014-01-01

    Isothermal compression/expansion is regarded as the most promising process in many applications and many researchers and inventors have tried different methods to achieve this goal. The current article first studies the gradual roadmap from adiabatic towards isothermal process from thermodynamics and heat transfer point of view. Different strategies are investigated to achieve this goal by evaluating different possibilities; the bottleneck of the problem is then identified and then increment ...

  2. An Isothermal Steam Expander for an Industrial Steam Supplying System

    Directory of Open Access Journals (Sweden)

    Chen-Kuang Lin

    2015-01-01

    Full Text Available Steam is an essential medium used in the industrial process. To ensure steam quality, small and middle scale boilers are often adopted. However, because a higher steam pressure (compared to the necessary steam pressure is generated, the boiler’s steam pressure will be reduced via a pressure regulator before the steam is directed through the process. Unfortunately, pressure is somewhat wasted during the reducing process. Therefore, in order to promote energy efficiency, a pressure regulator is replaced by a steam expander. With this steam expander, the pressure will be transformed into mechanical energy and extracted during the expansion process. A new type of isothermal steam expander for an industrial steam supplying system will be presented in the paper. The isothermal steam expander will improve the energy efficiency of a traditional steam expander by replacing the isentropic process with an isothermal expansion process. With this, steam condensation will decrease, energy will increase, and steam quality will be improved. Moreover, the mathematical model of the isothermal steam expander will be established by using the Schmidt theory, the same principle used to analyze Stirling engines. Consequently, by verifying the correctness of the theoretical model for the isothermal steam expander using experimental data, a prototype of 100 c.c. isothermal steam expander is constructed.

  3. High Temperature Behavior of Isothermally Compressed M50 Steel

    Institute of Scientific and Technical Information of China (English)

    Li-xing SUN; Miao-quan LI

    2015-01-01

    The isothermal compression of M50 steel is carried out on a Gleeble-3500 thermo-mechanical simulator in temperature range of 1 223—1 423 K and strain rates range of 10—70 s—1. The results show that the carbides play a signiifcant role in the lfow be-havior and microstructure evolution during isothermal compression of M50 steel. The average apparent activation energy for defor-mation in isothermal compression of M50 steel is (281.1±42.6) kJ∙mol—1 at the strains of 0.4—0.8. The dynamic recrystallization of austenite grains occurs in isothermal compression of M50 steel at 1 363 K and 1 393 K, enhancing with the increase of strain rate and/or strain. The volume fraction of the carbides decreases with the increase of deformation temperature during isothermal com-pression of M50 steel and the ifne carbides inhibit the dynamic recrystallization of austenite grain. With the occurrence of dynamic recrystallization, the austenite grains are reifned, leading to a minor increase in the lfow stress and apparent activation energy for deformation in isothermal compression of M50 steel. The austenite grains begin to coarsen at 1 423 K and dynamic recrystalliza-tion is limited. Hot working of M50 steel should not be performed above 1 393 K in order to achieve good workability.

  4. EFFICIENCY OF PROTECTIVE MEASURES TO REDUCE INTERNAL DOSE FROM CAESIUM RADIONUCLIDES FOR THE INHABITANTS OF RADIOACTIVE CONTAMINATION AREA IN THE FIRST YEARS AFTER THE CHERNOBYL ACCIDENT

    Directory of Open Access Journals (Sweden)

    I. G. Travnikova

    2012-01-01

    Full Text Available In the paper, we use the data on the content of caesium radionuclides in foodstuffs and in Bryansk region adult inhabitant’s body, on their food ration and its changes during the first years after the Chernobyl accident, and on the measures to protect the population from internal exposure. We calculate dynamics of 137Cs intake in the body and its contents therein, while maintaining a traditional diet and while replacing food products for radiationfree ones. The results show that the actual 137Cs content in the body is usually below the one calculated on the basis of the food ration. It was found out that individual 137Cs contents in the body correlate with the rate of meat, dairy and natural food products consumption and with factors of protection from internal exposure. The efficiency of the protective measures to reduce the intake and the content of caesium radionuclides in the body of inhabitants, as well as the average effective dose in the first years after the accident has been quantitatively assessed.

  5. Isothermal and non-isothermal crystallization kinetics of PVA + ionic liquid [BDMIM][BF4]-based polymeric films

    Science.gov (United States)

    Saroj, A. L.; Chaurasia, S. K.; Kataria, Shalu; Singh, R. K.

    2016-06-01

    The effect of ionic liquid (IL), 1-butyl-2,3-dimethylimidazolium tetrafluoroborate [BDMIM][BF4], on crystallization behavior of poly(vinyl alcohol) (PVA) has been studied by isothermal and non-isothermal differential scanning calorimetry techniques. The PVA + IL based polymer electrolyte films have been prepared using solution casting technique. To describe the isothermal and non-isothermal crystallization kinetics, several kinetic equations have been employed on PVA + IL based films. There is strong dependence of the peak crystallization temperature (Tc), relative degree of crystallity (Xt), half-time of crystallization (t1/2), crystallization rate constants (Avrami Kt and Tobin AT), and Avrami (n) and Tobin (nT) exponents on the cooling rate and IL loading.

  6. Migration, Skills and Productivity

    OpenAIRE

    Robert Hierländer; Peter Huber; Anna Iara; Michael Landesmann; Klaus Nowotny; Mary O'Mahony; Fei Peng; Catherine Robinson; Robert Stehrer

    2010-01-01

    The literature on international migration has repeatedly emphasized that the extent and structure of migration has an important impact on the competitiveness of regions and countries. This report provides an overview of the extent and the potential effects of high-skill migration to the EU27. It shows how many high-skilled migrants live in the EU, where these migrants come from, and how the European Union is positioned in the international competition for talent. Second, we examine how high-s...

  7. Impacts of planet migration models on planetary populations. Effects of saturation, cooling and stellar irradiation

    CERN Document Server

    Dittkrist, K -M; Klahr, H; Alibert, Y; Henning, T

    2014-01-01

    Context: Several recent studies have found that planet migration in adiabatic discs differs significantly from migration in isothermal discs. Depending on the thermodynamic conditions, i.e., the effectiveness of radiative cooling, and the radial surface density profile, planets migrate inward or outward. Clearly, this will influence the semimajor axis - mass distribution of planets as predicted by population synthesis simulations. Aims: Our goal is to study the global effects of radiative cooling, viscous torque desaturation and gap opening as well as stellar irradiation on the tidal migration of a synthetic planet population. Methods: We combine results from several analytical studies and 3D hydrodynamic simulations in a new semi-analytical migration model for the application in our planet population synthesis calculations. Results: We find a good agreement of our model with torques obtained in a 3D radiative hydrodynamic simulations. We find three convergence zones in a typical disc, towards which planets m...

  8. Kinetics and thermodynamics of interaction between sulfonamide antibiotics and humic acids: Surface plasmon resonance and isothermal titration microcalorimetry analysis.

    Science.gov (United States)

    Xu, Juan; Yu, Han-Qing; Sheng, Guo-Ping

    2016-01-25

    The presence of sulfonamide antibiotics in the environments has been recognized as a crucial issue. Their migration and transformation in the environment is determined by natural organic matters that widely exist in natural water and soil. In this study, the kinetics and thermodynamics of interactions between humic acids (HA) and sulfamethazine (SMZ) were investigated by employing surface plasmon resonance (SPR) combined with isothermal titration microcalorimetry (ITC) technologies. Results show that SMZ could be effectively bound with HA. The binding strength could be enhanced by increasing ionic strength and decreasing temperature. High pH was not favorable for the interaction. Hydrogen bond and electrostatic interaction may play important roles in driving the binding process, with auxiliary contribution from hydrophobic interaction. The results implied that HA existed in the environment may have a significant influence on the migration and transformation of organic pollutants through the binding process.

  9. Migration og etnicitet

    DEFF Research Database (Denmark)

    Christiansen, Connie Carøe

    2004-01-01

    Migration og etnicitet er aktuelle og forbundne fænomener, idet migration øger berøringsfladerne mellem befolkningsgrupper. Etniciteter formes i takt med at grænser drages imellem disse grupper. Imod moderniserings-teoriernes forventning forsvandt etnicitet ikke som en traditionel eller oprindelig...... måde at skabe tilhørsforhold på; globalt set fremstår vor tid istedet som en "migrationens tidsalder", der tilsyneladende også er en tidsalder, hvor kulturelle særtræk, i form af etnicitet, udgør vigtige linjer, hvorefter grupper skilller sig ud fra hinanden. Både migration og etnicitet bringer fokus...... den finder sted i modtagerlandet, men nyere perspektiver på migration, som begreber om medborgerskab, transnationalisme og diaspora er eksponenter for, søger udover den nationalstatslige ramme og inddrager konsekvenserne af migrationen for afsenderlande....

  10. 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. PMID:12347370

  11. Migration and malaria.

    Science.gov (United States)

    Jitthai, Nigoon

    2013-01-01

    Migration is an important global issue as poorly managed migration can result in a diversity of problems, including an increase in the transmission of diseases such as malaria. There is evidence to suggest that malaria is no longer a forest-dependent disease and may largely be affected by population movements, mostly to agricultural areas. While internal and transnational migration has different legal implications in most countries, both types of migration occur for the same reasons; economic and/ or safety. Although migration in itself is not a definitive risk for malaria, several factors can put, migrants and local communities alike, in vulnerable situations. In particular, infrastructure and rural development, deforestation for logging and economic farming, political movements, and natural disasters are some of the major factors that push and pull people in and out of malaria-endemic areas. Therefore, understanding the changing socio-environmental situation as well as population movements and their associated risks for malaria infection, is critical for malaria control, containment, and elimination. Efforts to address these issues should include advocacy, mapping exercises and expanded/ strengthened surveillance to also include migrant health information systems. Malaria related information, prevention measures, and early diagnosis and appropriate treatment should be made easily accessible for migrants regardless of their migration status; not only to ensure that they are equipped with appropriate knowledge and devices to protect themselves, but also to ensure that they are properly diagnosed and treated, to prevent further transmission, and to ensure that they are captured by the surveillance system. PMID:24159832

  12. Caesium absorption by barley - influence of its retention by the soil - competitive action of potassium; Absorption du cesium par l'orge - influence de sa retention dans le sol - action competitive du potassium

    Energy Technology Data Exchange (ETDEWEB)

    Ferron-Trosseau, F. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1964-06-01

    We have studied, in various culture media, how the absorption of caesium by barley varies with its concentration, and how this absorption can be in competition with a similar alkali cation-potassium. We have also considered the caesium distribution in the ground in particular radio-active caesium, between the soil and solution, as a function of the amount of caesium. From our work it is clear that barley behaves very differently according to whether the caesium is in a nutritive solution or is in the soil: for a nutritive solution, the fraction of caesium (radioactive and stable) absorbed by barley remains practically constant in the presence of increasing amounts (relatively small) of stable caesium; in soil, the fraction of the radio-active caesium absorbed increases as the stable caesium content (fairly low) of the soil increases, in relationship with a rapidly decreasing selectivity of the soil for Cs{sup +}. The difference between these results is thus explained by the very pronounced selectivity of the illitic soil studied for Cs{sup +}, as long as the proportion of Cs remains low, about as low as that of most natural soils. Furthermore, the K{sup +} ion is in competition with the Cs{sup +} ion, for absorption by barley in a culture medium in a nutritive solution or in soil, only when the potassium concentrations are relatively low, of the order of the nutritive maximum. This shows that the addition of potassium to a medium already rich in this element does not reduce the absorption of caesium by barley. The choice of experimental conditions close to natural conditions (nutritive media strong in calcium) and the examination of the distribution of radioactive caesium between the soil, the soil solution and the plant in the presence of very low doses of stable caesium make these results interesting from the 'atomic health' point of view; it should be expected that a definite contamination risk exists for plants cultivated on synthetic media and for

  13. The granulometrical fractions of soil, distributions of caesium-137 on its and the fastening of soil surface contaminated by radionuclides at locations of the 'Azgir test site'

    International Nuclear Information System (INIS)

    products of chain reaction in the moment of UGNE; radioactive ejections from spaces after explosions; contamination of locations during the break-down of spaces and a fulfilment of technological operations of different purposes; a burial of radioactive wastes in trenches in the limits of locations; local traces of atmospherical falls - out from radioactive clouds, formed as a result of the Chernobyl Catastrophe (traces were discovered during aero-gamma-spectro metrical surveys, carried out in the beginning of 1990). Accordingly to a change of granulometric composition there was taken place and a redistribution of caesium-137, the main part of which was concentrated in the fraction of 0.063 mm and was in limits of from 79.5% up to 92.2%. An efficiency of an action of polymeric composition, introduced into soil for fastening and binding of radionuclides in surface soil layer, can be estimated by data of measurements of caesium-137 distribution in granulometric fractions of soil samples, sieved and divided into 6 dimension components: 1.25 mm; 0.7 mm; 0.4 mm; 0.1 mm; 0.063 mm and <0.063 mm. Further, in indicated probes, by the method of wet sieving, there was also determined the granulometric composition by 6 above-mentioned fraction and the additional seventh fraction ('clay'), extracted during the wet sieving of soil samples. Then, in each obtained fraction there was measured the specific activity of caesium-137. In order to study the real distribution of caesium-137 on granulometric fractions there were measured specific activities of caesium-137 in all fractions, extracted after wet sieving and analogous to those, which were obtained during dry sieving, and in the fraction 'clay', formed during the process of wash-out of soil probes by water. The use of wet sieving had led to the redistribution of caesium-137 content in fractions, which was fixed by the method of dry sieving, where caesium-137 was mainly in fractions : 0.1 mm; 0.4 mm; 0.7 mm and 1.25 mm. In the same

  14. Single time point isothermal drug stability experiments at constant humidity.

    Science.gov (United States)

    Tao, Jian-Lin; Zhan, Xian-Cheng; Li, Lin-Li; Lin, Bing; Jiang, Lu

    2009-03-01

    A single time point isothermal drug stability experiments at constant humidity is introduced. In the new method, kinetic parameters related to both moisture and temperature were obtained by a single pair of experiments: these related to moisture by one with a group of testing humidities and a fixed temperature, those related to temperature by the other with a group of testing temperatures and a constant humidity. By a simulation, the estimates for the kinetic parameters (E(a), m, A) obtained by the proposed method and the reported programmed humidifying and heating method were statistically evaluated and were compared with those obtained by the isothermal measurements at constant humidity. Results indicated that under the same experimental conditions, the estimates obtained by the proposed method were significantly more precise than those obtained by the reported programmed humidifying and heating method. The estimates obtained by the isothermal method at constant humidity were somewhat more precise than those obtained by the proposed method. However, the experimental period needed by the isothermal method at constant humidity was greatly longer than that needed by the proposed method. The stability of dicloxacillin sodium, as a solid state model, was investigated by the single time point isothermal drug stability experiments at constant humidity. The results indicated that the kinetic parameters obtained by the proposed method were comparable to those from the reported. PMID:19252391

  15. Isothermal martensite formation at sub-zero temperatures

    DEFF Research Database (Denmark)

    Stojko, Allan; Hansen, Mikkel Fougt; Slycke, Jan;

    2010-01-01

    Sub-zero treatment of steels with an Mf below zero degrees Celsius relies (partly) on a continuation of the martensite formation. The present work reports on the observation of isothermal martensite formation in the sub-zero temperature regime for two steels: AISI 1070 and AISI 52100. Samples wer...... with a continuation of the martensitic transformation. On prolonged isothermal holding a volume reduction was observed for AISI 52100, but not for AISI 1070. A mechanism is proposed that explains the occurrence of isothermal martensite formation.......Sub-zero treatment of steels with an Mf below zero degrees Celsius relies (partly) on a continuation of the martensite formation. The present work reports on the observation of isothermal martensite formation in the sub-zero temperature regime for two steels: AISI 1070 and AISI 52100. Samples were...... austenitized and quenched in oil and thereafter investigated with vibrating sample agnetometry, which allows a quantitative assessment of the fraction of retained austenite as a function of the subzero temperature and time. Isothermal martensite formation was observed on interrupting the continuous cooling (5...

  16. Binding Isotherms and Time Courses Readily from Magnetic Resonance.

    Science.gov (United States)

    Xu, Jia; Van Doren, Steven R

    2016-08-16

    Evidence is presented that binding isotherms, simple or biphasic, can be extracted directly from noninterpreted, complex 2D NMR spectra using principal component analysis (PCA) to reveal the largest trend(s) across the series. This approach renders peak picking unnecessary for tracking population changes. In 1:1 binding, the first principal component captures the binding isotherm from NMR-detected titrations in fast, slow, and even intermediate and mixed exchange regimes, as illustrated for phospholigand associations with proteins. Although the sigmoidal shifts and line broadening of intermediate exchange distorts binding isotherms constructed conventionally, applying PCA directly to these spectra along with Pareto scaling overcomes the distortion. Applying PCA to time-domain NMR data also yields binding isotherms from titrations in fast or slow exchange. The algorithm readily extracts from magnetic resonance imaging movie time courses such as breathing and heart rate in chest imaging. Similarly, two-step binding processes detected by NMR are easily captured by principal components 1 and 2. PCA obviates the customary focus on specific peaks or regions of images. Applying it directly to a series of complex data will easily delineate binding isotherms, equilibrium shifts, and time courses of reactions or fluctuations. PMID:27458657

  17. Managing Migration: The Brazilian Case

    OpenAIRE

    Eduardo L. G. Rios-Neto

    2005-01-01

    The objective of this paper is to present the Brazilian migration experience and its relationship with migration management. The article is divided into three parts. First, it reviews some basic facts regarding Brazilian immigration and emigration processes. Second, it focuses on some policy and legal issues related to migration. Finally, it addresses five issues regarding migration management in Brazil.

  18. TOWARD MIGRATION TRANSITION IN ROMANIA

    OpenAIRE

    Cristian Incaltarau

    2012-01-01

    Most studies regarding the contribution of migration to development are limited to an isolated analysis of the economic effects of migration. But the migration process is in turn influenced by other processes. So a wider framework including migration and other processes of development would be more appropriate. The experience of South European and East Asian countries have shown us that, during development, countries can change their migration profile from emigration to immigration. The prese...

  19. Non-isothermal Moisture Transport Through Insulation Materials

    DEFF Research Database (Denmark)

    Peuhkuri, Ruut Hannele; Rode, Carsten; Hansen, Kurt Kielsgaard

    2008-01-01

    conclusions and therefore the question about existence of the type of transport forms driven by the non-isothermal effects remains open. Rather surprisingly, all the materials, including the almost non-hygroscopic materials (e.g. rock wool) and very hygroscopic materials (e.g. cellulose insulation) showed......An experimental investigation was conducted in order to draw some conclusions on the magnitude of moisture transport due to temperature gradient on a range of porous light-weight building materials. A special constructed non-isothermal set-up allowed the creation of a temperature gradient of 10K...... and given humidity gradient over the sample. The resulting moisture ux as well as the hygrothermal states around and within the material were monitored. The hypothesis of relative humidity being a driving force for non-isothermal moisture transport already in the hygroscopic range could not be confirmed...

  20. Determination of Differential Enthalpy and Isotherm by Adsorption Calorimetry

    Directory of Open Access Journals (Sweden)

    V. Garcia-Cuello

    2008-01-01

    Full Text Available An adsorption microcalorimeter for the simultaneous determination of the differential heat of adsorption and the adsorption isotherm for gas-solid systems are designed, built, and tested. For this purpose, a Calvet heat-conducting microcalorimeter is developed and is connected to a gas volumetric unit built in stainless steel to record adsorption isotherms. The microcalorimeter is electrically calibrated to establish its sensitivity and reproducibility, obtaining K=154.34±0.23 WV−1. The adsorption microcalorimeter is used to obtain adsorption isotherms and the corresponding differential heats for the adsorption of CO2 on a reference solid, such as a NaZSM-5 type zeolite. Results for the behavior of this system are compared with those obtained with commercial equipment and with other studies in the literature.

  1. Migration = cloning; aliasiing

    DEFF Research Database (Denmark)

    Hüttel, Hans; Kleist, Josva; Nestmann, Uwe;

    1999-01-01

    In Obliq, a lexically scoped, distributed, object-oriented programming language, object migration was suggested as the creation of a copy of an object’s state at the target site, followed by turning the object itself into an alias, also called surrogate, for the remote copy. We consider the creat......In Obliq, a lexically scoped, distributed, object-oriented programming language, object migration was suggested as the creation of a copy of an object’s state at the target site, followed by turning the object itself into an alias, also called surrogate, for the remote copy. We consider...... the creation of object surrogates as an abstraction of the abovementioned style of migration. We introduce Øjeblik, a distribution-free subset of Obliq, and provide three different configuration-style semantics, which only differ in the respective aliasing model. We show that two of the semantics, one of which...... matches Obliq’s implementation, render migration unsafe, while our new proposal for a third semantics is provably safe. Our work suggests a straightforward repair of Obliq’s aliasing model such that it allows programs to safely migrate objects....

  2. Isothermal Gas assisted displacement of a polystyrene melt

    DEFF Research Database (Denmark)

    Eriksson, Torbjörn Gerhard; Rasmussen, Henrik K.

    2007-01-01

    Isothermal gas displacements of a polystyrene melt (shaped as circular cylinder with a radius of 2.5mm) placed inside a circular steel annulus were performed. A flow valve ensures a constant flow rate and rotational symmetric flow during the displacement. The experiments show an increase in the s......Isothermal gas displacements of a polystyrene melt (shaped as circular cylinder with a radius of 2.5mm) placed inside a circular steel annulus were performed. A flow valve ensures a constant flow rate and rotational symmetric flow during the displacement. The experiments show an increase...

  3. Interpretation of Quasi-Isothermal Thermogravimetric Weight Curves

    DEFF Research Database (Denmark)

    Sørensen, Ole Toft

    1979-01-01

    Quasi-isothermal analysis (QIA) is a very useful technique. Compared to conventional non-isothermal thermogravimetry, close-lying reactions can easily be separated by use of this method and kinetic data can be obtained for each intermediate reaction in a single run. This paper discusses the shape...... of the weight and temperature curves expected in QIA for different controlling mechanisms, and a method is given for calculating the activation energies from these curves. As an example, the QIA curves obtained in thermal decomposition of ammonium-uranyl carbonate (AUC) are analysed and the kinetics of some...

  4. Effects of Schwarzschild Geometry on Isothermal Plasma Wave Dispersion

    CERN Document Server

    Sharif, M

    2007-01-01

    The behavior of isothermal plasma waves has been analyzed near the Schwarzschild horizon. We consider a non-rotating background with non-magnetized and magnetized plasmas. The general relativistic magnetohydrodynamical equations for the Schwarzschild planar analogue spacetime with an isothermal state of the plasma are formulated. The perturbed form of these equations is linearized and Fourier analyzed by introducing simple harmonic waves. The determinant of these equations in each case leads to a complex dispersion relation, which gives complex values of the wave number. This has been used to discuss the nature of the waves and their characteristics near the horizon.

  5. Dilatometric Investigation on Isothermal Transformation after Hot Deformation

    Institute of Scientific and Technical Information of China (English)

    CHEN Ying; CHEN Qi-an

    2003-01-01

    The DAFT (deformation assistant ferrite transformation) of austenite and reverse DIFT (deformation induced ferrite transformation) during isothermal holding after deformation were investigated by means of hot deformation simulator with laser dilatometer. It is found that the reverse DIFT can occur in a wide temperature region, from the temperature above Ae3 to below A r3. However, during the isothermal holding, the reverse DIFT and DAFT of austenite take place, and therefore, the volume variation during holding time may be the combined effect of both phase transformations mentioned above. Nevertheless, the total volume and then the phase volume fraction change slowly, especially at lower holding temperature.

  6. En fornemmelse for migration

    DEFF Research Database (Denmark)

    Schütze, Laura Maria

    Afhandlingen undersøger, hvordan sted, museets rolle som aktør og religion er relevante for produktionen af migration på Immigrantmuseet (2012) og i Københavns Museums udstilling At blive københavner (2010). Afhandlingen er baseret på udstillingsanalyse samt interview med relevant museumsfagligt......, anvendes som virkemidler til at nuancere migration og distancere udstillingen fra den offentlige debat om indvandring. Afhandlingen peger på, at produktionen af den nyere danske historie på museum er præget af et fravær af religion. Det skyldes, at de museumsfaglige praksisser og traditioner afspejler en...... identiteter, som vi tager for givet: nationer, byer, kvinder - såvel som migration og religion. Afhandlingen argumenterer følgelig for, at museernes produktion af (materiel) religion er et særdeles relevant, men kun ringe udforsket, genstandsfelt for religionssociologien....

  7. Monitoring of caesium-137 in food plants and muscle from moose, red deer and wild reindeer in 2010.; Overvaaking av cesium-137 i beitevekster og kjoett av elg, hjort og villrein i 2010.

    Energy Technology Data Exchange (ETDEWEB)

    Veiberg, Vebjoern; Gaare, Eldar; Stokke, Sigbjoern; Solberg, Erling J.; Skuterud, Lavrans

    2011-07-01

    The monitoring of Cs-137 fall-out from the Chernobyl accident in 1986, started the same year. Several plants and wild reindeer in natural ecosystems in Nord-Rondane have been followed annually ever since. Four more wild reindeer ranges were included in 2001: Setesdal-Ryfylkeheiene, Hardangervidda, Nord-Ottadalen, Snoehetta and Nord-Rondane. From 2007 Forollhogna was also included. On fixed plots in Nord-Rondane and Snoehetta some of the reindeer forage plants, including both higher plants and fruticose lichens, have been sampled and analyzed annually since 1986. This was also done in 2010. In addition plants and lichens were sampled at five locations along an altitudinal gradient at Soendre Knutshoe, and at 7-8 locations along an east-west gradient from Kollaflata to Skarhoe in the Jora valley continuing along the Aursjoe to Torbudalen. All these locations were sampled annually between 1987-1990, but they have not been sampled since. In 2010 samples from red deer and moose was also collected from eight different regions located within the following counties: Oppland, Telemark, Vest-Agder, Rogaland, Sogn and Fjordane, Nord-Troendelag, Nordland and Troms. Red deer were sampled in four regions and moose in six. Both species were sampled in Oppland. In 2010 76, 49 and 61 samples were collected from wild reindeer, red deer and moose respectively. All measures of caesium levels were performed on dried samples. For the 596 samples of plants and lichen the results refer to caesium-levels in dried samples. For the meat samples, results refer to caesium-137 levels in raw meat. Due to large variation in measured levels of caesium within species and sampling area, we give median values instead of mean values.The highest caesium levels in wild reindeer were found in Snoehetta (1010 Bq/kg) and Nord-Rondane (2686 Bq/kg). The levels found in the other areas were considerably lower. The highest caesium levels in both red deer (Sel, 677 Bq/kg) and moose (Vaaga, 365 Bq/kg) were found

  8. THE CONTENT OF CAESIUM-137 IN THE RIVERSIDE AND WATER VEGETATION VETKA AND CHECHERSK DISTRICTS OF THE GOMEL REGION OF BELARUS

    Directory of Open Access Journals (Sweden)

    N. M. Dajneko

    2014-01-01

    Full Text Available The content of radiocaesium was studied in 58 plant samples in 2 districts with only 12 (20,6% exceeding the allowable level which equals 370 Bk/kg. In Vetka district the highest specific activity of caesium-137 (Bk/kg was demonstrated by Equisetum arvense and Comarum palustre among the medium-sized euhydrophytes in  the  second  object,  which  3,7  and  5,2  times  exceeds  the  standard.   Ceratophyllum  demersum  has  the  highest accumulation coefficient. In Chechesk district medium-sized euhydrophytes Juncus effusus and Sium latifolium in the second object exceed the standard 7,8–2,2 times. Stratiotes aloides demonstrates the highest accumulation coefficient.

  9. Is Migration Feminized?

    OpenAIRE

    Toksöz, Gülay

    2012-01-01

    In the context of Turkey’s accession to the EU, the issue of potential migration from Turkey and its impact upon European labor markets became one of the concerns of the EU, considering Turkey’s growing population and young labor force. In 2011, half a century after the bi-lateral agreement between Turkey and Germany on labor recruitment in 1961, migration plays a key role in relations of Turkey with the EU and will even increase its significance – not necessarily for the next fifty years bu...

  10. International Migration of Couples

    DEFF Research Database (Denmark)

    Munk, Martin D.; Junge, Martin; Poutvaara, Panu

    2016-01-01

    Migrant self-selection is important to both origin and destination countries. We develop a theoretical model regarding the migration of dual-earner couples and test it in the context of international migration, using population-wide administrative data from Denmark. Our model predicts...... that the probability that a couple emigrates increases with the primary earner’s income, whereas the secondary earner’s income may drive the decision in either direction. The results are consistent with our model. We find that primary earners in couples are more strongly self-selected with respect to income than...... singles. This novel result counters the intuition that family ties weaken self-selection....

  11. What's driving migration?

    Science.gov (United States)

    Kane, H

    1995-01-01

    During the 1990s investment in prevention of international or internal migration declined, and crisis intervention increased. The budgets of the UN High Commissioner for Refugees and the UN Development Program remained about the same. The operating assumption is that war, persecution, famine, and environmental and social disintegration are inevitable. Future efforts should be directed to stabilizing populations through investment in sanitation, public health, preventive medicine, land tenure, environmental protection, and literacy. Forces pushing migration are likely to increase in the future. Forces include depletion of natural resources, income disparities, population pressure, and political disruption. The causes of migration are not constant. In the past, migration occurred during conquests, settlement, intermarriage, or religious conversion and was a collective movement. Current migration involves mass movement of individuals and the struggle to survive. There is new pressure to leave poor squatter settlements and the scarcities in land, water, and food. The slave trade between the 1500s and the 1800s linked continents, and only 2-3 million voluntarily crossed national borders. Involuntary migration began in the early 1800s when European feudal systems were in a decline, and people sought freedom. Official refugees, who satisfy the strict 1951 UN definition, increased from 15 million in 1980 to 23 million in 1990 but remained a small proportion of international migrants. Much of the mass movement occurs between developing countries. Migration to developed countries is accompanied by growing intolerance, which is misinformed. China practices a form of "population transfer" in Tibet in order to dilute Tibetan nationalism. Colonization of countries is a new less expensive form of control over territory. Eviction of minorities is another popular strategy in Iraq. Public works projects supported by foreign aid displace millions annually. War and civil conflicts

  12. Migrating for a Profession

    DEFF Research Database (Denmark)

    Olwig, Karen Fog

    2015-01-01

    Youths from the Global South migrating for further education often face various forms of discrimination. This Caribbean case study discusses how conditions in the home country can provide a foundation for educational migration that helps the migrants overcome such obstacles and even develop...... a strong sense of agency and self-empowerment. In the post-WWII period, numerous Caribbean women trained in nursing at British hospitals that have been described as marred by race and gender related inequality and associated forms of exploitation. Yet, the nurses interviewed about this training emphasised...

  13. Migration, klima og sundhed

    DEFF Research Database (Denmark)

    Tellier, Siri; Carballo, Manuel

    2009-01-01

    Many tentative connections have been postulated between migration and climate. This article points to rural-urban migration, particularly into low elevation urban slums prone to flooding as an issue needing urgent attention by health professionals. It also notes the no-man's land in which...... environmental refugees find themselves and the consequences this may have. Finally, it points to the urgent need to reform health systems in both developing and developed countries to adapt to rapidly changing disease patterns and to become more responsive to them. Udgivelsesdato: 2009-Oct-26...

  14. Making Migration Meaningful

    DEFF Research Database (Denmark)

    Benwell, Ann Fenger

    2013-01-01

    . The article focuses on changing patterns of mobility in the Mongolian ‘age of the market’ and its effects on population groups. Internal and international migration has continually risen as individuals and families have moved to places of opportunity. Connections are believed to be maintained during periods...... of absence by migrant family members, as both men and women are culturally permitted to be separate from their families. Migration is understood to contribute to prosperity, and separations contribute to generate growth and hishig (good fortune) for the good of the family. However, such mobility is also...

  15. Unix Application Migration Guide

    CERN Document Server

    Microsoft. Redmond

    2003-01-01

    Drawing on the experience of Microsoft consultants working in the field, as well as external organizations that have migrated from UNIX to Microsoft® Windows®, this guide offers practical, prescriptive guidance on the issues you are likely to face when porting existing UNIX applications to the Windows operating system environment. Senior IT decision makers, network managers, and operations managers will get real-world guidance and best practices on planning and implementation issues to understand the different methods through which migration or co-existence can be accomplished. Also detailing

  16. [Migration, climate and health].

    Science.gov (United States)

    Tellier, Siri; Carballo, Manuel; Calballo, Manuel

    2009-10-26

    Many tentative connections have been postulated between migration and climate. This article points to rural-urban migration, particularly into low elevation urban slums prone to flooding as an issue needing urgent attention by health professionals. It also notes the no-man's land in which environmental refugees find themselves and the consequences this may have. Finally, it points to the urgent need to reform health systems in both developing and developed countries to adapt to rapidly changing disease patterns and to become more responsive to them. PMID:19857400

  17. Migration strategies of insects.

    Science.gov (United States)

    Dingle, H

    1972-03-24

    Physiological and ecological results from a variety of species are consistent with what seem to be valid general statements concerning insect migration. These are as follows: (i)During migration locomotory functions are enhanced and vegetative functions such as feeding and reproduction are suppressed. (ii) Migration usually occurs prereproductively in the life of the adult insect (the oogenesis-flight syndrome). (iii)Since migrant individuals are usually prereproductive, their reproductive values, and hence colonizing abilities, are at or near maximum. (iv) Migrants usually reside in temporary habitats. (v)Migrants have a high potential for population increase, r, which is also advantageous for colonizers. (vi)Both the physiological and ecological parameters of migration are modifiable by environmental factors (that is, phenotypically modifiable)to suit the prevailing conditions. Taken together, these criteria establish a comprehensive theory and adumbrate the basic strategy for migrant insects. This basic strategy is modified to suit the ecological requirements of individual species. Comparative studies of these modifications are of considerable theoretical and practical interest, the more so since most economically important insects are migrants. No satisfactory general statements can as yet be made with respect to the genotype and migration. Certainly we expect colonizing populiations to possess genotypes favoring a high r, but genotypic variation in r depends on the heritabilities of life table statistics, and such measurements are yet to be made (10, 53). The fact that flight duration can be increased by appropriate selection in Oncopeltus fasciatus, and the demonstration of additive genetic variance for this trait in Lygaeus kalmii, suggest that heritability studies of migratory behavior would also be worth pursuing. Most interesting of course, will be possible genetic correlations between migration and life history parameters. Also, migration often

  18. Low dose rate caesium-137 implant time of intracavitary brachytherapy source of a selected oncology center in Ghana

    Directory of Open Access Journals (Sweden)

    John Owusu Banahene

    2015-01-01

    Full Text Available Background: The treatment time taken for a radioactive source is found to be very important in intracavitary brachytherapy treatment. The duration of the treatment time depends on the prescribed dose requested to a reference point and the calculated dose rate to the same point. The duration of the treatment time of source is found to depend on the tumour stage. In this work, the treatment time of implant has been calculated for a Caesium-137 low dose rate brachytherapy source at an oncology facility in Ghana. Objective: The objective was to determine how the treatment time of tumours depends on the dose rate to the reference point prescribed by the Oncologists and the dose rate determined by the dosimetrists at the facility. Materials and Method: Depending upon the stage of the cancer, the Oncologist determines the type of treatment modality, source configuration for the cancer patient and positions of both tandem and ovoids in the cervix. Depending also on the tumour stage, two orthogonal radiographic X-ray films are taken using a simulator machine. The treatment machine used in the study is AMRA-Curietron. The maximum activity of the source was 259GBq. It has five channels which is a manual remote afterloader. In clinical practice, the treatment time t is very short(only some few days for such low dose rate brachytherapy source like Cs-137 which lasts only for some few days in comparison with the half life of the Cs-137 source. The mathematical equation for the calculation of treatment time is written as t=D/D. Hence t is the treatment time of the radioactive source of patients undergoing intracavitary brachytherapy treatment, D is prescribed dose to a reference point and D is the dose rate to the same reference point. Results: The calculated treatment time of the Cs-137 brachytherapy source for different source arrangements or channels used in clinical practice at the brachytherapy Centre have been determined. Also provided, are the

  19. Migration scenarii in extrasolar systems

    Directory of Open Access Journals (Sweden)

    Crida A.

    2011-02-01

    Full Text Available In this review talk, I present the theory of type I migration of small mass planets, and its latest developments that open the possibility of outward migration in the inner part of a protoplanetary disk. I also review the type II migration of giant planets, and mention the runaway, type III. Then, we focus on the migration of pairs of planets in resonance. The eccentricity of the planets raise, and possibly their mutual inclination as well. Also, the migration rate can be changed, and directed outward if the outer planet is the lighter. Last, we present a synthetic scenario of migration for the giant planets of our Solar System.

  20. Friction factor for isothermal and nonisothermal flow through porous media

    Science.gov (United States)

    Koh, J. C.; Dutton, J. L.; Benson, B. A.; Fortini, A.

    1977-01-01

    Measurements were performed to determine the pressure drops for gaseous flow through porous materials of different microstructures, porosities, and thickness under isothermal and nonisothermal conditions at various temperature levels. Results were satisfactorily correlated by a simple equation relating the friction factor to the Reynolds number and porosities.

  1. Isothermal Titration Calorimetry Can Provide Critical Thinking Opportunities

    Science.gov (United States)

    Moore, Dale E.; Goode, David R.; Seney, Caryn S.; Boatwright, Jennifer M.

    2016-01-01

    College chemistry faculties might not have considered including isothermal titration calorimetry (ITC) in their majors' curriculum because experimental data from this instrumental method are often analyzed via automation (software). However, the software-based data analysis can be replaced with a spreadsheet-based analysis that is readily…

  2. ISOTHERMAL AND THERMOMECHANICAL FATIGUE OF A NICKEL-BASE SUPERALLOY

    Directory of Open Access Journals (Sweden)

    Carlos Carvalho Engler-Pinto Júnior

    2014-06-01

    Full Text Available Thermal gradients arising during transient regimes of start-up and shutdown operations produce a complex thermal and mechanical fatigue loading which limits the life of turbine blades and other engine components operating at high temperatures. More accurate and reliable assessment under non-isothermal fatigue becomes therefore mandatory. This paper investigates the nickel base superalloy CM 247LC-DS under isothermal low cycle fatigue (LCF and thermomechanical fatigue (TMF. Test temperatures range from 600°C to 1,000°C. The behavior of the alloy is strongly affected by the temperature variation, especially in the 800°C-1,000°C range. The Ramberg-Osgood equation fits very well the observed isothermal behavior for the whole temperature range. The simplified non-isothermal stress-strain model based on linear plasticity proposed to represent the thermo-mechanical fatigue behavior was able to reproduce the observed behavior for both in-phase and out-of-phase TMF cycling.

  3. Isothermal martensite formation at sub-zero temperatures

    DEFF Research Database (Denmark)

    Stojko, Allan; Hansen, Mikkel Fougt; Slycke, Jan;

    2012-01-01

    Sub-zero treatment of steels with an Mf below 0°C relies (partly) on a continuation of the martensite formation. The present work reports on the observation of isothermal martensite formation in the sub-zero temperature regime for two steels: AISI 1070 and AISI 52100. Samples were austenitized, q...... with a continuation of the martensitic transformation. On prolonged isothermal holding, a volume reduction was observed for AISI 52100, but not for AISI 1070. Copyright © 2011 by ASTM International.......Sub-zero treatment of steels with an Mf below 0°C relies (partly) on a continuation of the martensite formation. The present work reports on the observation of isothermal martensite formation in the sub-zero temperature regime for two steels: AISI 1070 and AISI 52100. Samples were austenitized......, quenched in oil, and thereafter investigated with vibrating sample magnetometry, which allows a quantitative assessment of the fraction of retained austenite as a function of the sub-zero temperature and time. Isothermal martensite formation was observed on interrupting the continuous cooling (5 K...

  4. Isothermal martensite formation at sub-zero temperatures

    DEFF Research Database (Denmark)

    Stojko, Allan; Hansen, Mikkel Fougt; Slycke, Jan;

    2011-01-01

    Sub-zero treatment of steels with an M1 below 0°C relies (partly) on a continuation of the martensite formation. The present work reports on the observation of isothermal martensite formation in the sub-zero temperature regime for two steels: AISI 1070 and AISI 52100. Samples were austenitized, q...... with a continuation of the martensitic transformation. On prolonged isothermal holding, a volume reduction was observed for AISI 52100, but not for AISI 1070. Copyright © 2011.......Sub-zero treatment of steels with an M1 below 0°C relies (partly) on a continuation of the martensite formation. The present work reports on the observation of isothermal martensite formation in the sub-zero temperature regime for two steels: AISI 1070 and AISI 52100. Samples were austenitized......, quenched in oil, and thereafter investigated with vibrating sample magnetometry, which allows a quantitative assessment of the fraction of retained austenite as a function of the sub-zero temperature and time. Isothermal martensite formation was observed on interrupting the continuous cooling (5 K...

  5. Derivation of the Freundlich Adsorption Isotherm from Kinetics

    Science.gov (United States)

    Skopp, Joseph

    2009-01-01

    The Freundlich adsorption isotherm is a useful description of adsorption phenomena. It is frequently presented as an empirical equation with little theoretical basis. In fact, a variety of derivations exist. Here a new derivation is presented using the concepts of fractal reaction kinetics. This derivation provides an alternative basis for…

  6. Fall armyworm migration patterns.

    Science.gov (United States)

    Fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), infestations in most of North America arise from annual migrations of populations that overwinter in southern Texas and Florida. Cytochrome Oxidase I haplotype profiles within the fall armyworm corn-strain, the subgroup tha...

  7. Digitizing migration heritage

    DEFF Research Database (Denmark)

    Marselis, Randi

    2011-01-01

    Museums are increasingly digitizing their collections and making them available to the public on-line. Creating such digital resources may become means for social inclusion. For museums that acknowledge migration history and cultures of ethnic minority groups as important subjects in multiethnic...

  8. Migration as Adventure

    DEFF Research Database (Denmark)

    Olwig, Karen Fog

    2016-01-01

    Narratives of adventure constitute a well-established convention of describing travel experiences, yet the significance of this narrative genre in individuals’ accounts of their migration and life abroad has been little investigated. Drawing on Simmel and Bakhtin, among others, this article...

  9. Migration and Africa

    DEFF Research Database (Denmark)

    Zoppi, Marco

    2014-01-01

    European powers imposed the nation-state on Africa through colonialism. But even after African independencies, mainstream discourses and government policies have amplified the idea that sedentariness and the state are the only acceptable mode of modernity. Migration is portrayed as a menace...

  10. Migrating the Light

    DEFF Research Database (Denmark)

    Sørensen, Bent

    The migration of Blaga’s universalist, even centralist poems from Romanian of the first third of the 20th C. into American of the first fifth of the 21st C. illustrates the uses of Pierre Joris’s nomadic methods. My translations of Blaga read well for a teenage audience whose only exposure...

  11. Practical Data Migration

    CERN Document Server

    Morris, Johny

    2012-01-01

    This book is for executives and practitioners tasked with the movement of data from old systems to a new repository. It uses a series of steps guaranteed to get the reader from an empty new system to one that is working and backed by the user population. Using this proven methodology will vastly increase the chances of a successful migration.

  12. Dispersal and migration

    Directory of Open Access Journals (Sweden)

    Schwarz, C.

    2004-06-01

    Full Text Available Ringing of birds unveiled many aspects of avian migration and dispersal movements. However, there is even much more to be explored by the use of ringing and other marks. Dispersal is crucial in understanding the initial phase of migration in migrating birds as it is to understand patterns and processes of distribution and gene flow. So far, the analysis of migration was largely based on analysing spatial and temporal patters of recoveries of ringed birds. However, there are considerable biases and pitfalls in using recoveries due to spatial and temporal variation in reporting probabilities. Novel methods are required for future studies separating the confounding effects of spatial and temporal heterogeneity of recovery data and heterogeneity of the landscape as well. These novel approaches should aim a more intensive and novel use of the existing recovery data by taking advantage of, for instance, dynamic and multistate modeling, should elaborate schemes for future studies, and should also include other marks that allow a more rapid data collection, like telemetry, geolocation and global positioning systems, and chemical and molecular markers. The latter appear to be very useful in the delineating origin of birds and connectivity between breeding and non–breeding grounds. Many studies of migration are purely descriptive. However, King and Brooks (King & Brooks, 2004 examine if movement patterns of dolphins change after the introduction of a gillnet ban. Bayesian methods are an interesting approach to this problem as they provide a meaningful measure of the probability that such a change occurred rather than simple yes/no response that is often the result of classical statistical methods. However, the key difficulty of a general implementation of Bayesian methods is the complexity of the modelling —there is no general userfriendly package that is easily accessible to most scientists. Drake and Alisauskas (Drake & Alisauskas, 2004 examine the

  13. Migration and Narration

    Directory of Open Access Journals (Sweden)

    Brigitte Boenisch-Brednich

    2002-05-01

    Full Text Available The following article aims to work out the main narrative techniques of “telling migration”. The conclusions drawn on the subject of migration and narration are based on a one-year field work study, combining participant observation with interviewing. This study took place in New Zealand concentrating on German immigrants between 1936 and 1996. The main source for my analysis given in this paper is provided by 102 people I interviewed. The texts of these biographically-focussed interviews allowed me to work not only on an ethnographical history of migration but also to gain insights into peoples’ experiences, and over and above that, to learn what kind of stories and techniques of storytelling emigration creates. The book focuses on a comparatively wide time frame of sixty years (Boenisch- Brednich 2001. This makes it possible to analyse very different periods of migration and groups of migrants, contrasting social categories as well as exploring differences in education, milieu, age and gender. Furthermore, it becomes obvious that although all migrants were leaving Germany and arriving in New Zealand, they experienced what were in effect very different countries through time – different Germanys, different New Zealands. To work out the changing reasons for migrating (work migration, refuge, global lifestyle, etc. inside western societies is a major theme the book is aiming for. A second approach is to investigate migration from the perspective of focussing on everyday life, an investigation on the basis of personal experiences, such as “work, housing, food, celebrations, social life”. A special focus is set on the analysing of “mental narratives” as key stories, examples, comparatives etc. The central questions of this project were: What kind of strategies do people use to cope with a major changes in their biography, as constituted by emigration? What does integration really mean and how does it work for different groups? What

  14. Migration Turnover Rates in Mountain States Counties

    OpenAIRE

    Israelsen, William J.; Israelsen, L. Dwight; Israelsen, Ryan D.

    2006-01-01

    Studies of migration typically examine migration between countries, or, in the United States, migration between states. Recently, there have been several studies done on the determinants of migration at the county level. The current study introduces a new concept into the migration literature: the migration turnover rate (MTR). The migration turnover rate is similar to an employee turnover rate in that it measures the turnover through in-migration and out-migration of the population of an are...

  15. Migration Turnover Rates in United States Counties

    OpenAIRE

    Israelsen, L. Dwight; Israelsen, Ryan D.; Israelsen, William J.

    2006-01-01

    Studies of migration typically examine migration between countries, or, in the United States, migration between states. Recently, there have been several studies done on the determinants of migration at the county level. The current study introduces a new concept into the migration literature: the migration turnover rate (MTR). The migration turnover rate is similar to an employee turnover rate in that it measures the turnover through in-migration and out-migration of the population of an are...

  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 International Organization for Migration in Global Migration Governance

    OpenAIRE

    Poulsen, Sofie Havn; Andersen, Lise

    2011-01-01

    This project focuses on the IOM, the notion of global governance of migration and the interaction between these two. The point of departure has been an attempt to grasp the current global approach to migration and comprehend whether, or to what degree, there is governance of migration issues taking place at a global level.

  18. Modelling granite migration by mesoscale pervasive flow

    Science.gov (United States)

    Leitch, A. M.; Weinberg, R. F.

    2002-06-01

    Mesoscale pervasive magma migration leads to granite injection complexes, common in hot crustal terranes. Pervasive migration is limited by magma freezing when intruding cold country rock. Here, we explore numerically the feedback mechanism between magma intrusion and heating of the country rock, which allows younger intrusive batches to reach increasingly shallower/cooler levels. This process relies on the higher solidus temperature of a rock compared to that of its melt, once melt is segregated. We define the 'free-ride layer' as the region above the melt source, where magma may freely migrate because rock temperature is above melt solidus. The top of the free-ride layer, which corresponds to the melt solidus ( TS) isotherm, is at the 'limiting depth', zS. After magma passes through the free-ride layer, the magma 'front' is always at the limiting depth. We modeled the thickening and heating of the crust above the source as melt at its liquidus ( TL) intrudes it pervasively from below. We found that: (a) magma quickly warms crust below zS to about TL, forming a step in temperature at zS; (b) the front ( zS) moves up through the crust as more magma is intruded; (c) as magma is emplaced at the front, a mingled layer of about half magma half crust forms below it, so that the total rise of the front corresponds approximately to half of the thickness of magma added to the free-ride layer; (d) the rate of rise of the front depends on the temperature difference between crust and TL, and slows down as the magma front rises; (e) for most reasonable intrusion rates and volumes, the crust above zS feels little influence of the intrusion, because the diffusion time scale is much smaller than the rise rate of the front. In summary, pervasive migration is an efficient way of heating the lower to middle crust, and can result in an injection complex several kilometers thick, consisting of about half magma and half original crust.

  19. CHARACTERISTICS OF MIGRATION IN ROMANIA

    Directory of Open Access Journals (Sweden)

    Daniela DĂNĂCICĂ

    2010-06-01

    Full Text Available The aim of this research is to study the patterns of migration in Romania. Labor migration in Romania has seen major growth after 1989. Permanent migration rapidly increased in the early years after the revolution, decreasing rapidly thereafter, due to difficulties of obtaining long term residence and work permit in the host countries. However, temporary migration has been found to evolve very dynamically, requiring economic analysis of potential externalities, whether positive or the negative of this phenomenon.

  20. CHARACTERISTICS OF MIGRATION IN ROMANIA

    OpenAIRE

    Daniela DĂNĂCICĂ

    2010-01-01

    The aim of this research is to study the patterns of migration in Romania. Labor migration in Romania has seen major growth after 1989. Permanent migration rapidly increased in the early years after the revolution, decreasing rapidly thereafter, due to difficulties of obtaining long term residence and work permit in the host countries. However, temporary migration has been found to evolve very dynamically, requiring economic analysis of potential externalities, whet...

  1. Trade, Aid, Remittances and Migration

    OpenAIRE

    Akkoyunlu, Sule

    2009-01-01

    I investigated whether migration is interrelated with trade, aid and remittances so that any policies that consider trade, aid and remittances also affect the decision to migrate. We developed and estimated an empirical model of Turkish migration to Germany and tested the model for the 1969-2004, using the cointegration technique. A single cointegrating vector is found among the gross migration inflows and the following explanatory variables: the relative income ratio between Germany and Turk...

  2. Altruism and International Labour Migration

    OpenAIRE

    Damien Gaumont; Alice Mesnard

    1999-01-01

    This paper investigates the effect of altruism on the pattern of labour migration in a two-country overlapping generations model. We show that differences in degrees of altruism across countries lead to bilateral migration flows. Starting from the autarkic steady-state equilibrium, restrictions on labour migration are relaxed. In temporary post-migration equilibrium factor prices are equal across countries. We then characterize the unique stable steady-state equilibrium: both countries are po...

  3. The definition of illegal migration

    OpenAIRE

    DZHANSARAYEVA RIMA YERENATOVNA; MALIKOVA SHOLPAN BALTABEKOVNA

    2015-01-01

    The article analyzes the definitions of illegal migration. In theory, there is no consensus on the concept of illegal immigration. In the scientific revolution applied the concept of “illegal migration”, “illegal immigration”, “migration of the crime” and “criminal migration”. Crime and illegal migration, although they have common features, are different concepts. For the concept of illegal immigration is characterized by violation of migration laws. For the concept of mandatory criminal migr...

  4. Halting Migration: Numerical Calculations of Corotation Torques in the Weakly Nonlinear Regime

    CERN Document Server

    Duffell, Paul C

    2014-01-01

    Planets in their formative years can migrate due to the influence of gravitational torques in the protoplanetary disk they inhabit. For low-mass planets in an isothermal disk, it is known that there is a strong negative torque on the planet due to its linear perturbation to the disk, causing fast inward migration. The current investigation demonstrates that in these same isothermal disks, for intermediate-mass planets, there is a strong positive nonlinear corotation torque due to the effects of gas being pulled through a gap on horseshoe orbits. For intermediate-mass planets, this positive torque can partially or completely cancel the linear (Type I) torque, leading to slower or outward migration, even in an isothermal disk. The effect is most significant for Super-Earth and Sub-Jovian planets, during the transition from a low-mass linear perturber to a non-linear gap-opening planet, when the planet has opened a so-called 'partial gap'. In this study, numerical calculations of planet-disk interactions calcula...

  5. Religion, migration og integration

    DEFF Research Database (Denmark)

    Borup, Jørn

    2010-01-01

    Sammenhængen mellem religion og integration har de sidste år været genstand for debat. Artiklen kommer ind på begreber og sammenhænge relateret til området (migration, diaspora, assimilation, etnicitet, kultur) og ser på religionens mulige rolle som negativ eller positiv ressource i integrationss......Sammenhængen mellem religion og integration har de sidste år været genstand for debat. Artiklen kommer ind på begreber og sammenhænge relateret til området (migration, diaspora, assimilation, etnicitet, kultur) og ser på religionens mulige rolle som negativ eller positiv ressource i...

  6. Correlation of adsorption isotherms of hydrogen isotopes on mordenite adsorbents using reactive vacancy solution theory

    Energy Technology Data Exchange (ETDEWEB)

    Munakata, K.; Nakamura, A. [Faculty of Engineering and Ressource Science, Akita University, Akita-shi, Akita (Japan); Kawamura, Y. [Japan Atomic Energy Agency -JAEA, Tokai, Ibaraki (Japan)

    2015-03-15

    The authors have applied the isotherm equations derived from the reactive vacancy solution theory (RVST) to correlation of experimental and highly non-ideal adsorption isotherms of hydrogen and deuterium on a mordenite adsorbent, and have examined the ability of the isotherm equations to match this correlation. Several isotherm equations such as Langmuir, Freundlich, Toth, Vacancy Solution Theory and so forth were also tested, but they did not work. For the Langmuir-Freundlich equation tests have indicated that its 'ability to correlate' of the adsorption isotherms is not satisfactory. For the multi-site Langmuir-Freundlich (MSLF) equation the correlation of the isotherms appears to be somewhat improved but remains unsatisfactory. The results show that the isotherm equations derived from RVST can better correlate the experimental isotherms.

  7. Migration with fiscal externalities.

    Science.gov (United States)

    Hercowitz, Z; Pines, D

    1991-11-01

    "This paper analyses the distribution of a country's population among regions when migration involves fiscal externalities. The main question addressed is whether a decentralized decision making [by] regional governments can produce an optimal population distribution...or a centralized intervention is indispensable, as argued before in the literature.... It turns out that, while with costless mobility the fiscal externality is fully internalized by voluntary interregional transfers, with costly mobility, centrally coordinated transfers still remain indispensable for achieving the socially optimal allocation."

  8. Enforcement and illegal migration

    OpenAIRE

    Orrenius, Pia

    2014-01-01

    Border enforcement of immigration laws attempts to raise the costs of illegal immigration, while interior enforcement also lowers the benefits. Border and interior enforcement therefore reduce the net benefits of illegal immigration and should lower the probability that an individual will decide to migrate. While some empirical studies find that border and interior enforcement serve as significant deterrents to illegal immigration, immigration enforcement is costly and carries significant uni...

  9. Managing the Mass Migration

    Institute of Scientific and Technical Information of China (English)

    Lan Xinzhen

    2012-01-01

    Big crowds and foul air on the train,frighteningly long queues and fierce clashes at the station...these are common scenes during China's Spring Festival travel rush.The annual travel peak is known as the world's biggest human migration.This year's stampede is still ongoing.Lasting over 40 days,people began retuming to their hometowns on January 8 and the final stragglers will make their way back to the cities by February 16.

  10. MIGRATION AND POLITICAL ASYLUM

    OpenAIRE

    LUPSA FLORENTINA

    2014-01-01

    Migration is an important topic on the public agenda, as well as in the area of effervescent political debate and public policies, and has been so especially in this past decade, in the national and European plane. The recorded evolutions may easily exemplify the way in which liberal democracies function and the process of European construction, implicitly the process of change in the immigration policy, degree of adaptability and opening to change, the controversial character and the difficu...

  11. Halting Planetary Migration

    OpenAIRE

    Lecar, M.; Sasselov, D. D.

    1999-01-01

    When Jupiter's Roche Lobe radius exceeded the scale height of the protoplanetary disk, Jupiter opened a gap in the disk. When the gap was wide enough, tidal torques from the disk interior and exterior to Jupiter were suppressed and migration continued on the accretion time scale. In the 'minimum solar nebula' about two Jupiter masses of gas remained between Jupiter and Saturn and about five Jupiter masses between Jupiter and Uranus. Unless all but a Jupiter mass of the outer disk was removed,...

  12. Syrian Crisis and Migration

    OpenAIRE

    Pinar Yazgan; Deniz Eroglu Utku; Ibrahim Sirkeci

    2015-01-01

    With the growing insurrections in Syria in 2011, an exodus in large numbers have emerged. The turmoil and violence have caused mass migration to destinations both within the region and beyond. The current "refugee crisis" has escalated sharply and its impact is widening from neighbouring countries toward Europe. Today, the Syrian crisis is the major cause for an increase in displacement and the resultant dire humanitarian situation in the region. Since the conflict shows no signs of abating i...

  13. Conservation physiology of animal migration.

    Science.gov (United States)

    Lennox, Robert J; Chapman, Jacqueline M; Souliere, Christopher M; Tudorache, Christian; Wikelski, Martin; Metcalfe, Julian D; Cooke, Steven J

    2016-01-01

    Migration is a widespread phenomenon among many taxa. This complex behaviour enables animals to exploit many temporally productive and spatially discrete habitats to accrue various fitness benefits (e.g. growth, reproduction, predator avoidance). Human activities and global environmental change represent potential threats to migrating animals (from individuals to species), and research is underway to understand mechanisms that control migration and how migration responds to modern challenges. Focusing on behavioural and physiological aspects of migration can help to provide better understanding, management and conservation of migratory populations. Here, we highlight different physiological, behavioural and biomechanical aspects of animal migration that will help us to understand how migratory animals interact with current and future anthropogenic threats. We are in the early stages of a changing planet, and our understanding of how physiology is linked to the persistence of migratory animals is still developing; therefore, we regard the following questions as being central to the conservation physiology of animal migrations. Will climate change influence the energetic costs of migration? Will shifting temperatures change the annual clocks of migrating animals? Will anthropogenic influences have an effect on orientation during migration? Will increased anthropogenic alteration of migration stopover sites/migration corridors affect the stress physiology of migrating animals? Can physiological knowledge be used to identify strategies for facilitating the movement of animals? Our synthesis reveals that given the inherent challenges of migration, additional stressors derived from altered environments (e.g. climate change, physical habitat alteration, light pollution) or interaction with human infrastructure (e.g. wind or hydrokinetic turbines, dams) or activities (e.g. fisheries) could lead to long-term changes to migratory phenotypes. However, uncertainty remains

  14. Conservation physiology of animal migration.

    Science.gov (United States)

    Lennox, Robert J; Chapman, Jacqueline M; Souliere, Christopher M; Tudorache, Christian; Wikelski, Martin; Metcalfe, Julian D; Cooke, Steven J

    2016-01-01

    Migration is a widespread phenomenon among many taxa. This complex behaviour enables animals to exploit many temporally productive and spatially discrete habitats to accrue various fitness benefits (e.g. growth, reproduction, predator avoidance). Human activities and global environmental change represent potential threats to migrating animals (from individuals to species), and research is underway to understand mechanisms that control migration and how migration responds to modern challenges. Focusing on behavioural and physiological aspects of migration can help to provide better understanding, management and conservation of migratory populations. Here, we highlight different physiological, behavioural and biomechanical aspects of animal migration that will help us to understand how migratory animals interact with current and future anthropogenic threats. We are in the early stages of a changing planet, and our understanding of how physiology is linked to the persistence of migratory animals is still developing; therefore, we regard the following questions as being central to the conservation physiology of animal migrations. Will climate change influence the energetic costs of migration? Will shifting temperatures change the annual clocks of migrating animals? Will anthropogenic influences have an effect on orientation during migration? Will increased anthropogenic alteration of migration stopover sites/migration corridors affect the stress physiology of migrating animals? Can physiological knowledge be used to identify strategies for facilitating the movement of animals? Our synthesis reveals that given the inherent challenges of migration, additional stressors derived from altered environments (e.g. climate change, physical habitat alteration, light pollution) or interaction with human infrastructure (e.g. wind or hydrokinetic turbines, dams) or activities (e.g. fisheries) could lead to long-term changes to migratory phenotypes. However, uncertainty remains

  15. Many Faces of Migrations

    Directory of Open Access Journals (Sweden)

    Milica Antić Gaber

    2013-12-01

    We believe that in the present thematic issue we have succeeded in capturing an important part of the modern European research dynamic in the field of migration. In addition to well-known scholars in this field several young authors at the beginning their research careers have been shortlisted for the publication. We are glad of their success as it bodes a vibrancy of this research area in the future. At the same time, we were pleased to receive responses to the invitation from representatives of so many disciplines, and that the number of papers received significantly exceeded the maximum volume of the journal. Recognising and understanding of the many faces of migration are important steps towards the comprehensive knowledge needed to successfully meet the challenges of migration issues today and even more so in the future. It is therefore of utmost importance that researchers find ways of transferring their academic knowledge into practice – to all levels of education, the media, the wider public and, of course, the decision makers in local, national and international institutions. The call also applies to all authors in this issue of the journal.

  16. Design of a high current extraction/strypping system using extraction and stripping isotherms

    OpenAIRE

    Danovska, Milena; Karanfilov, Dejan; Golomeova, Mirjana; Krstev, Boris; Zendelska, Afrodita

    2015-01-01

    The isotherms define the capacity of some extragent for its capability to extract required metal (in this case copper). They are used to evaluate how the system extraction/stripping works, or expected to work. The construction of extraction isotherm consists of the following stages: preparation of laboratory extragent, the organic phase is brought into contact with the electrolyte, optimization of the extraction equilibrium isotherm. Similarly, construct and stripping isotherm: or...

  17. Migrations in Slovenian geography textbooks

    Directory of Open Access Journals (Sweden)

    Jurij Senegačnik

    2013-12-01

    Full Text Available In Slovenia, the migrations are treated in almost all geographical textbooks for different levels of education. In the textbooks for the elementary school from the sixth to ninth grade, students acquire knowledge of the migrations by the inductive approach. Difficulty level of treatment and quantity of information are increasing by the age level. In the grammar school program a trail of gaining knowledge on migration is deductive. Most attention is dedicated to migrations in general geography textbooks. The textbooks for vocational and technical school programs deal with migrations to a lesser extent and with different approaches.

  18. Migration process in Russia in 2010

    OpenAIRE

    Lilia Karachurina

    2011-01-01

    This paper deals with a scope of issues related to migration process taking place in the Russian Federation. The author focuses on the issues of labor migration and domestic migration. New legislative initiatives in the area of migration were reviewed.

  19. Migration Processes in Russia in 2011

    OpenAIRE

    Lilia Karachurina

    2012-01-01

    This paper deals with a scope of issues related to migration process taking place in the Russian Federation. The author focuses on the issues of labor migration and domestic migration. New legislative initiatives in the area of migration were reviewed.

  20. Entropy variation in isothermal fluid flow considering real gas effects

    Directory of Open Access Journals (Sweden)

    Maurício Guimarães da Silva

    2011-01-01

    Full Text Available The present paper concerns on the estimative of the pressure loss and entropy variation in an isothermal fluid flow, considering real gas effects. The 1D formulation is based on the isothermal compressibility module and on the thermal expansion coefficient in order to be applicable for both gas and liquid as pure substances. It is emphasized on the simple methodology description, which establishes a relationship between the formulation adopted for ideal gas and another considering real gas effects. A computational procedure has been developed, which can be used to determine the flow properties in duct with a variable area, where real gas behavior is significant. In order to obtain quantitative results, three virial coefficients for Helium equation of state are employed to determine the percentage difference in pressure and entropy obtained from different formulations. Results are presented graphically in the form of real gas correction factors, which can be applied to perfect gas calculations.

  1. Equilibrium Sequences and Gravitational Instability of Rotating Isothermal Rings

    CERN Document Server

    Kim, Woong-Tae

    2016-01-01

    Nuclear rings at centers of barred galaxies exhibit strong star formation activities. They are thought to undergo gravitational instability when sufficiently massive. We approximate them as rigidly-rotating isothermal objects and investigate their gravitational instability. Using a self-consistent field method, we first construct their equilibrium sequences specified by two parameters: alpha corresponding to the thermal energy relative to gravitational potential energy, and R_B measuring the ellipticity or ring thickness. Unlike in the incompressible case, not all values of R_B yield an isothermal equilibrium, and the range of R_B for such equilibria shrinks with decreasing alpha. The density distributions in the meridional plane are steeper for smaller alpha, and well approximated by those of infinite cylinders for slender rings. We also calculate the dispersion relations of nonaxisymmetric modes in rigidly-rotating slender rings with angular frequency Omega_0 and central density rho_max. Rings with smaller ...

  2. Resolving vortices with an isothermal HLLC Riemann solver

    CERN Document Server

    Jung, Manuel; Duschl, Wolfgang J

    2015-01-01

    The importance of contact discontinuities in 2D isothermal flows has rarely been discussed, since most Riemann solvers are derived for 1D Euler equations. We present a new contact resolving approximate Riemann solver for the isothermal Euler equations and show its performance for several one- and two-dimensional test problems. The new solver extends the well-known HLL solver, while retaining its computational simplicity. The significant gain in resolution of vortices is displayed by a simulation of the K\\'arm\\'an vortex street. We discuss the loss of Galilean invariance and its implications for the resolution of contact discontinuities, which is experienced by all modern numerical schemes for hydrodynamics in non-moving grids.

  3. Self-similar solutions to isothermal shock problems

    CERN Document Server

    Deschner, Stephan C; Duschl, Wolfgang J

    2016-01-01

    We investigate exact solutions for isothermal shock problems in different one-dimensional geometries. These solutions are given as analytical expressions if possible, or are computed using standard numerical methods for solving ordinary differential equations. We test the numerical solutions against the analytical expressions to verify the correctness of all numerical algorithms. We use similarity methods to derive a system of ordinary differential equations (ODE) yielding exact solutions for power law density distributions as initial conditions. Further, the system of ODEs accounts for implosion problems (IP) as well as explosion problems (EP) by changing the initial or boundary conditions, respectively. Taking genuinely isothermal approximations into account leads to additional insights of EPs in contrast to earlier models. We neglect a constant initial energy contribution but introduce a parameter to adjust the initial mass distribution of the system. Moreover, we show that due to this parameter a constant...

  4. Non-isothermal Decomposition Kinetics of K(AHDNE)

    Institute of Scientific and Technical Information of China (English)

    L(U) Lei; XU Kang-zhen; QIU Qian-qian; WANG Gang; SONG Ji-rong; ZHAO Feng-qi

    2012-01-01

    The thermal behavior and non-isothermal decomposition kinetics of 1-amino-1-hydrazino-2,2-dinitroethylene potassium salt[K(AHDNE)] were studied under the non-isothermal conditions by different scanning calorimeter(DSC) method.The thermal behavior of K(AHDNE) presents three exothermic decomposition processes.The kinetic equation of the first thermal decomposition reaction obtained is da/dT=(101963/β)3(1-α)[-ln(1-α)]2/3exp(-1.862× 105/RT).The self-accelerating decomposition temperature(TSADT) and critical temperature of thermal explosion(Tb) of K(AHDNE) are 162.5 and 171.4 ℃,respectively.K(AHDNE) has higher thermal stability than AHDNE.

  5. Multifractal characteristics of Nitrogen adsorption isotherms from tropical soils

    Science.gov (United States)

    Vidal Vázquez, Eva; Paz Ferreiro, Jorge

    2010-05-01

    One of the primary methods used to characterize a wide range of porous materials, including soils, are gas adsorption isotherms. An adsorption isotherm is a function relating the amount of adsorbed gas or vapour to the respective equilibrium pressure, during pressure increase at constant temperature. Adsorption data allow easily estimates of specific surface area and also can provide a characterization of pore surface heterogeneity. Most of the properties and the reactivity of soil colloids are influenced by their specific surface area and by parameters describing the surface heterogeneity. For a restricted scale range, linearity between applied pressure and volume of adsorbate holds, which is the basis for current estimations of specific surface area. However, adsorption isotherms contain also non-linear segments of pressure versus volume so that evidence of multifractal scale has been demonstrated. The aim of this study was to analyze the multifractal behaviour of nitrogen adsorption isotherms from a set of tropical soils. Samples were collected form 54 horizons belonging to 19 soil profiles in the state of Minas Gerais, Brazil. The most frequent soil type was Oxisol, according to the Soil Survey Staff, equivalent to Latossolo in the Brazilian soil classification system. Nitrogen adsorption isotherms at standard 77 K were measured using a Thermo Finnigan Sorptomatic 1990 gas sorption analyzer (Thermo Scientific, Waltham, MA). From the raw data a distributions of mass along a support was obtained to perform multifractal analysis. The probability distribution was constructed by dividing the values of the measure in a given segment by the sum of the measure in the whole scale range. The box-counting method was employed to perform multifractal analysis. All the analyzed N2 adsorption isotherms behave like a multifractal system. The singularity spectra, f(α), showed asymmetric concave down parabolic shapes, with a greater tendency toward the left side, where moments

  6. Relation between Tolman length and isothermal compressibility for simple liquids

    Institute of Scientific and Technical Information of China (English)

    Wang Xiao-Song; Zhu Ru-Zeng

    2013-01-01

    The Tolman length δ0 of a liquid with a plane surface has attracted increasing theoretical attention in recent years,but the expression of Tolman length in terms of observable quantities is still not very clear.In 2001,Bartell gave a simple expression of Tolman length δ0 in terms of isothermal compressibility.However,this expression predicts that Tolman length is always negative,which is contrary to the results of molecular dynamics simulations (MDS) for simple liquids.In this paper,this contradiction is analyzed and the reason for the discrepancy in the sign is found.In addition,we introduce a new expression of Tolman length in terms of isothermal compressibility for simple fluids not near the critical points under some weak restrictions.The Tolman length of simple liquids calculated by using this formula is consistent with that obtained using MDS regarding the sign.

  7. Non-isothermal spreading of liquid drops on horizontal plates

    International Nuclear Information System (INIS)

    A viscous-liquid drop spreads on a smooth horizontal surface, which is uniformly heated or cooled. Lubrication theory is used to study thin drops subject to capillary, thermocapillary and gravity forces, and a variety of contact-angle-versus-speed conditions. It is found for isothermal drops that gravity is very important at large times and determines the power law for unlimited spreading. Predictions compare well with the experimental data on isothermal spreading for both two-dimensional and axisymmetric configurations. It is found that heating (cooling) retards (augments) the spreading process. When the advancing contact angle is zero, heating will cause the drop to spread only finitely far. For positive advancing contact angles, sufficient cooling will cause unlimited spreading. Thus, the heat transfer serves as a sentitive control on the spreading. (orig.)

  8. Non-Isothermal Desolvation Kinetics of Erythromycin A Acetone Solvate

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The desolvation of erythromycin acetone solvate was investigated under non-isothermal conditions by a thermogravimetric analyzer. This paper emphasized the kinetic analysis of non-isothermal TG-DTA data by Achar method and Coats-Redfern method to fit various solid-state reaction models, and to achieve kinetic parameters of desolvation. The mechanism of thermal desolvation was evaluated using the kinetic compensation effect. The results show that kinetics of desolvation of erythromycin acetone solvate was compatible with the mechanism of a two-dimensional diffusion controlled and was best expressed by Valensi equation. Corresponding to the integral method and the differential method, the activation energy of desolvation of erythromycin acetone solvate was estimated to be 51.26-57.11 kJ/mol, and the pre-exponential factor was 8.077 × 106 s-1-4.326 × 107 s-1,respectively.

  9. Application of isothermal current deep level transient spectroscopy to solar cells

    Science.gov (United States)

    Rancour, D. P.; Pierret, R. F.; Lundstrom, M. S.; Melloch, M. R.

    1989-03-01

    The utility of isothermal current deep level transient spectroscopy (DLTS) techniques in directly probing solar cells is described and illustrated. A modified approach to processing the isothermal DLTS data is also presented. Specifically, it is pointed out that properly normalized isothermal data, whether derived from a current or capacitance transient, should conform to a single, temperature-independent curve.

  10. Monitoring assembly of ribonucleoprotein complexes by isothermal titration calorimetry

    OpenAIRE

    Recht, Michael I.; Ryder, Sean P.; Williamson, James R.

    2008-01-01

    Isothermal titration calorimetry (ITC) is a useful technique to study RNA-protein interactions, as it provides the only method by which the thermodynamic parameters of free energy, enthalpy, and entropy can be directly determined. This chapter presents a general procedure for studying RNA-protein interactions using ITC, and gives specific examples for monitoring the binding of Caenorhabditis elegans GLD-1 STAR domain to TGE RNA and the binding of Aquifex aeolicus S6:S18 ribosomal protein hete...

  11. Isothermal pumping analysis for high-altitude tethered balloons

    OpenAIRE

    Kuo, Kirsty A.; Hunt, Hugh E.M.

    2015-01-01

    High-altitude tethered balloons have potential applications in communications, surveillance, meteorological observations and climate engineering. To maintain balloon buoyancy, power fuel cells and perturb atmospheric conditions, fluids could be pumped from ground level to altitude using the tether as a hose. This paper examines the pumping requirements of such a delivery system. Cases considered include delivery of hydrogen, sulfur dioxide (SO2) and powders as fluid-based slurries. Isothermal...

  12. Unsteady Heat Transfer From a Non Isothermal Rotating Disc

    Directory of Open Access Journals (Sweden)

    Bal Krishan

    1967-01-01

    Full Text Available An analytic solution of the energy equation is obtained for a non-isothermal disc rotating in an incompressible fluid at rest neglecting the viscous dissipation. Initially the disc and the fluid are at a common temperature. Without altering the velocity, the disc temperature is then changed and maintained at temperature varying according to the power law of radial distance. Expressions for temperature distribution in the fluid for large and small times have been evaluated.

  13. Isothermal Crystallization Kinetics of Palm Oil with Additives

    OpenAIRE

    Su, N.; Li, Y. M.; X.P. Bai; Zhang, Y.Z.; Liu, H. X.; Li, J.Q.; Jie, P

    2015-01-01

    This study investigates the isothermal crystallization kinetics of palm oil with additives by Differential Scanning Calorimetry (DSC). The induction time of nucleation and crystallization are obtained by simulating the crystal process using the Gompertz model. The equilibrium melting temperature is obtained via the Hoffman-Weeks methods. The Gibbs free energy of nucleation was calculated by using the Fisher-Turnbull equation and the equilibrium melting temperature. The results indicate that t...

  14. Simplified models for estimating isothermal operating characteristics of food extruders.

    Science.gov (United States)

    Levine, L; Rockwood, J

    1985-09-01

    A model of isothermal food extruder performance is described. Inferences about alternative extruder screw designs and their performance are drawn from the model. The model suggests that thread depth or diameter compression screws are superior in performance to a pitch compression screw. The advantage gained from using diameter compression screws is paid for with significantly higher rates of energy dissipation. The use of the model to characterize screws having both a compression zone and metering zone is described.

  15. Isothermal glass transitions in supercooled and overcompressed liquids

    Science.gov (United States)

    Alba-Simionesco, C.

    1994-02-01

    We report the first calorimetric characterization of isothermal glass transitions obtained by changing the pressure at constant temperature. This isothermal glass transition is described in the case of m-fluoroaniline, a so-called fragile liquid. The method employed is based on Maxwell's equations and involves measurement of the heat of compression of a sample enclosed in a hydrostatic pressure cell under isothermal and reversible conditions. A discontinuity of the thermodynamic quantity αV, where α is the expansivity and V is the molar volume, defines the glass transition pressure Pg at which ergodicity is broken on the time scale of the experiments (300-1000 s) which depends on the pressure step employed. The step in αV is found initially to decrease rapidly with increasing pressure. The slope (∂Pg/∂T)τ seems smaller than that determined by the usual isobaric methods, implying some distinction in the degrees of freedom involved and associated differences in defining the values of Tg. Because of the high sensitivity and stability of the calorimeter, we can also observe annealing effects in the overcompressed glass at a pressure above Pg; the slow dynamic processes associated are called entropic relaxation because it is the entropy which is measured directly. An approximate relaxation function and a model for the compression data are discussed. Keeping in mind the overall pattern of ``strong and fragile'' liquid behavior, isothermal pressure variations appear to offer a useful tool to connect these extremes and may constrain the glass transition of a molecular liquid in a particular range of the P-T diagram. The concept of Kauzmann pressure PK is introduced, but it is noted that PK must become less well defined the further from ambient pressure it lies due to the decrease in ΔαV which is observed with increasing pressure.

  16. Sorption Isotherms and Probability Theory of Complex Systems

    OpenAIRE

    Brouers, F.

    2013-01-01

    We show that most of the empirical or semi-empirical isotherms proposed to extend the Langmuir formula to sorption (adsorption, chimisorption and biosorption) on heterogeneous surfaces in the gaseous and liquid phase belong to the family and subfamily of the Burr_{XII} cumulative distribution functions. As a consequence they obey relatively simple differential equations which describe birth and death phenomena resulting from mesoscopic and microscopic physicochemical processes. Using the prob...

  17. Can Hydrostatic Cores Form Within Isothermal Molecular Clouds?

    OpenAIRE

    Vazquez-Semadeni, Enrique; Shadmehri, Mohsen; Ballesteros-Paredes, Javier

    2002-01-01

    Under the assumptions that molecular clouds are nearly spatially and temporally isothermal and that the density peaks (``cores'') within them are formed by turbulent fluctuations, we argue that cores cannot reach a hydrostatic (or magneto-static) state as a consequence of their formation process. In the non-magnetic case, stabilization requires a Bonnor-Ebert truncation at a finite radius, which is not feasible for a single-temperature flow, unless it amounts to a shock, which is clearly a dy...

  18. Rapid compressions in a captive bubble apparatus are isothermal

    OpenAIRE

    Yan, Wenfei; Hall, Stephen B.

    2003-01-01

    Captive bubbles are commonly used to determine how interfacial films of pulmonary surfactant respond to changes in surface area, achieved by varying hydrostatic pressure. Although assumed to be isothermal, the gas phase temperature (Tg) would increase by >100°C during compression from 1 to 3 atm if the process were adiabatic. To determine the actual change in temperature, we monitored pressure (P) and volume (V) during compressions lasting 10 min after the compression when the two phases shou...

  19. Micromechanisms of thermomechanical fatigue: A comparison with isothermal fatigue

    Science.gov (United States)

    Bill, R. C.

    1986-01-01

    Thermomechanical Fatigue (TMF) experiments were conducted on Mar-M 200, B-1900, and PWA-1480 (single crystals) over temperature ranges representative of gas turbine airfoil environments. The results were examined from both a phenomenological basis and a micromechanical basis. Depending on constituents present in the superalloy system, certain micromechanisms dominated the crack initiation process and significantly influenced the TMF lives as well as sensitivity of the material to the type TMF cycle imposed. For instance, high temperature cracking around grain boundary carbides in Mar-M 200 resulted in short in-phase TMF lives compared to either out-of-phase or isothermal lives. In single crystal PWA-1480, the type of coating applied was seen to be the controlling factor in determining sensitivity to the type of TMF cycle imposed. Micromechanisms of deformation were observed over the temperature range of interest to the TMF cycles, and provided some insight as to the differences between TMF damage mechanisms and isothermal damage mechanisms. Finally, the applicability of various life prediction models to TMF results was reviewed. Current life prediction models based on isothermal data must be modified before being generally applied to TMF.

  20. DuPont IsoTherming clean fuel technology

    Energy Technology Data Exchange (ETDEWEB)

    Levinski, E. [E.I. DuPont Co., Wilmington, DE (United States)

    2009-07-01

    This poster described a hydroprocessing technology that DuPont has acquired from Process Dynamics, Inc. The IsoTherming clean fuel technology significantly reduces sulphur in motor fuels. The technology provides petroleum refiners the solution for meeting ultra low sulphur diesel requirements, at much lower costs than conventional technologies. IsoTherming hydroprocessing operates in a kinetically limited mode, with no mass transfer limitation. Hydrogen is delivered to the reactor in the liquid phase as soluble hydrogen, allowing for much higher space velocities than conventional hydrotreating reactors. Treated diesel is recycled back to the inlet of the reactor, generating less heat and more hydrogen into the reactor. The process results in a more isothermal reactor operation that allows for better yields, fewer light ends and greater catalyst life. The technology reduces coking, because the process provides enough hydrogen in the solution when cracking reactions take place. As a result, the process yields longer catalyst life. Other advantages for refiners include lower total investment; reduced equipment delivery lead times; reduced maintenance and operating costs; and configuration flexibility. tabs., figs.

  1. Isothermal dust models of Herschel-ATLAS galaxies

    CERN Document Server

    Smith, D J B; Jarvis, M J; Maddox, S J; Dunne, L; Bonfield, D G; Eales, S; Serjeant, S; Thompson, M A; Baes, M; Clements, D L; Cooray, A; De Zotti, G; Gonzàlez-Nuevo, J; van der Werf, P; Virdee, J; Bourne, N; Dariush, A; Hopwood, R; Ibar, E; Valiante, E

    2013-01-01

    We use galaxies from the Herschel-ATLAS survey, and a suite of ancillary simulations based on an isothermal dust model, to study our ability to determine the effective dust temperature, luminosity and emissivity index of 250um selected galaxies in the local Universe (z < 0.5). As well as simple far-infrared SED fitting of individual galaxies based on chi^2 minimisation, we attempt to derive the best global isothermal properties of 13,826 galaxies with reliable optical counterparts and spectroscopic redshifts. Using our simulations, we highlight the fact that applying traditional SED fitting techniques to noisy observational data in the Herschel Space Observatory bands introduces artificial anti-correlation between derived values of dust temperature and emissivity index. This is true even for galaxies with the most robust detections in our sample, making the results hard to interpret. We apply a method to determine the best-fit global values of isothermal effective temperature and emissivity index for z <...

  2. Disjoining pressure isotherms of water-in-bitumen emulsion films.

    Science.gov (United States)

    Taylor, Shawn D; Czarnecki, Jan; Masliyah, Jacob

    2002-08-01

    In the oil sands industry, undesirable water-in-oil emulsions are often formed during the bitumen recovery process where water is used to liberate bitumen from sand grains. Nearly all of the water is removed except for a small percentage (approximately 1 to 2%), which remains in the solvent-diluted bitumen as micrometer-sized droplets. Knowledge of the colloidal forces that stabilized these water droplets would help to increase our understanding of how these emulsions are stabilized. In this study, the thin liquid film-pressure balance technique has been used to measure isotherms of disjoining pressure in water/toluene-diluted bitumen/water films at five different toluene-bitumen mass ratios. Even though a broad range of mass ratios was studied, only two isotherms are obtained, indicating a possible change in the molecular orientation of surfactant molecules at the bitumen/water interfaces. At low toluene-bitumen mass ratios, the film stability appears to be due to a strong, short-range steric repulsion created by a surfactant bilayer. Similar isotherms were obtained for water/toluene-diluted asphaltene/water films, indicating that the surface active material at the interface probably originated from the asphaltene fraction of the bitumen. However, unlike the bitumen films, films of toluene-diluted asphaltenes often formed very rigid interfaces similar to the "protective skin" described by other researcher. PMID:16290773

  3. Study of adsorption isotherms of green coconut pulp

    Directory of Open Access Journals (Sweden)

    Fábia Carolina Gonçalves Lavoyer

    2013-03-01

    Full Text Available Brazil is considered one of the largest producers and consumers of tropical fruits. Green coconut (Cocos nucifera L. stands out not only for its production and consumption, but also for the high amount of waste produced by coconut water industry and in natura consumption. Therefore, there is a need for utilization of this by-product. This study aims to study the adsorption isotherms of green coconut pulp and determine its isosteric heat of sorption. The adsorption isotherms at temperatures of 30, 40, 50, 60, and 70 °C were analyzed, and they exhibit type III behavior, typical of sugar rich foods. The experimental results of equilibrium moisture content were correlated by models present in the literature. The Guggenheim, Anderson and De Boer (GAB model proved particularly good overall agreement with the experimental data. The heat of sorption determined from the adsorption isotherms increased with the decrease in moisture content. The heat of sorption is considered as indicative of intermolecular attractive forces between the sorption sites and water vapor, which is an important factor to predict the shelf life of dried products.

  4. Giant Planet Formation: A First Classification of Isothermal Protoplanetary Equilibria

    CERN Document Server

    Pecnik, B

    2005-01-01

    We present a model for the equilibrium of solid planetary cores embedded in a gaseous nebula. From this model we are able to extract an idealized roadmap of all hydrostatic states of the isothermal protoplanets. The complete classification of the isothermal protoplanetary equilibria should improve the understanding of the general problem of giant planet formation, within the framework of the nucleated instability hypothesis. We approximate the protoplanet as a spherically symmetric, isothermal, self-gravitating classical ideal gas envelope in equilibrium, around a rigid body of given mass and density, with the gaseous envelope required to fill the Hill-sphere. Starting only with a core of given mass and an envelope gas density at the core surface, the equilibria are calculated without prescribing the total protoplanetary mass or nebula density. The static critical core masses of the protoplanets for the typical orbits of 1, 5.2, and 30 AU, around a parent star of 1 solar mass are found to be 0.1524, 0.0948, a...

  5. Non-isothermal Crystallization Kinetics of Kaolin Modified Polyester

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ruixin; GU Mingbo; CHEN Guoqiang

    2011-01-01

    Fiber-class modified kaolin and PET have been blended in the twin-screw and granulated to chips containing 4 wt% of kaolin.Non-isothermal crystallization process of kaolin modified polyester was investigated using a differential scanning calorimetry (DSC),and the addition of kaolin enhances either the melting temperature (Tm) or the crystallization temperature (Tc).The morphology of kaolin modified polyester,the melt of which is cooled at different cooling rate,was observed by scanning electron microscope (SEM).The relationship between Tc and cooling rate F was studied.Semi-crystalline phase t1/2 makes an exponential decline with increasing F,and the higher the cooling rate,the shorter the time of crystallization completion.Non-isothermal crystallization kinetics parameters and the activation energy were calculated,indicating that the higher rate of cooling needs the higher relative crystallinity in the unit crystallization time,the crystallization rate increased while speeding up the temperature reduction,and the activation energy AE was calculated to be -204.1566 kJ/mol for the non-isothermal crystallization processes by the Kissinger's methods.

  6. Isothermal α″ formation in β metastable titanium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Aeby-Gautier, E., E-mail: Elisabeth.Gautier@mines.inpl-nancy.fr [Institut Jean Lamour, UMR CNRS Nancy Université, UPVM 7198, Nancy (France); Settefrati, A. [Institut Jean Lamour, UMR CNRS Nancy Université, UPVM 7198, Nancy (France); Airbus Operations, Materials and Processes, Toulouse (France); Bruneseaux, F. [Institut Jean Lamour, UMR CNRS Nancy Université, UPVM 7198, Nancy (France); Appolaire, B. [Laboratoire d’Etudes des Microstructures ONERA – CNRS Chatillon (France); Denand, B.; Dehmas, M.; Geandier, G.; Boulet, P. [Institut Jean Lamour, UMR CNRS Nancy Université, UPVM 7198, Nancy (France)

    2013-11-15

    Highlights: ► Isothermal kinetics of orthorhombic α″ formation is characterized by HEXRD. ► Cell parameters of parent and product phases are obtained. ► Partitioning of solutes during the transformation and the ageing is discussed. -- Abstract: Thanks to time resolved high energy X-ray diffraction, isothermal decomposition of β metastable phase was studied, directly after solution treatment in the β temperature range, for temperatures ranging from 300 to 450 °C for two beta metastable alloys (Ti 17 and Ti 5553). The formation of an orthorhombic α″ phase is clearly identified at the beginning of the transformation whatever the alloy studied. If transformation occurs at the higher temperature an evolution of α″ is observed toward the hexagonal α phase. The phase amounts and the mean cell parameters of each phase were quantified by the Rietveld refinement method. The obtained cell parameters evolutions and the orthorhombicity of α″ are discussed. Moreover, the orthorhombicity of α″ compared to that obtained for stress induced martensite may indicate a slight partitioning of solutes in isothermal α″.

  7. Gravitational lensing properties of an isothermal universal halo profile

    Institute of Scientific and Technical Information of China (English)

    Xin-Zhong Er

    2013-01-01

    N-body simulations predict that dark matter halos with different mass scales are described by a universal model,the Navarro-Frenk-White (NFW) density profiles.As a consequence of baryonic cooling effects,these halos will become more concentrated,and similar to an isothermal sphere over a large range in radii (~ 300 h-1 kpc).The singular isothermal sphere (SIS) model however has to be truncated artificially at large radii since it extends to infinity.We model a massive galaxy halo as a combination of an isothermal sphere and an NFW density profile.We give an approximation for the mass concentration at different baryon fractions and present exact expressions for the weak lensing shear and flexion for such a halo.We compare the lensing properties with the SIS and NFW profiles.We find that the combined profile can generate higher order lensing signals at small radii and is more efficient in generating strong lensing events.In order to distinguish such a halo profile from the SIS or NFW profiles,one needs to combine strong and weak lensing constraints for small and large radii.

  8. Adsorption Isotherms of Phenol and 4-Chlorophenol on Petroleum Asphaltenes Adsorption du phénol et du 4-chlorophénol sur les asphaltènes pétroliers

    Directory of Open Access Journals (Sweden)

    Jaoui M.

    2006-11-01

    Full Text Available The adsorption isotherms for phenol and 4-chlorophenol from water onto asphaltenes flocculated in bulk and asphaltenes deposited on silica were established by frontal analysis chromatography at 293, 298, 303, and 308 K. The adsorption was more important with asphaltenes flocculated in bulk and corresponded to a Freundlich isotherm mechanism. The high adsorbed amount of phenols suggests possible migration of phenols through the loose asphaltene structure. Isotherms observed with the silica coated by asphaltenes showed that adsorption occurs in two stages corresponding probably to two different organizations of solute molecules at the surface. Les isothermes d'adsorption du phénol et du 4-chlorophénol en solution dans l'eau sur des asphaltènes floculés en masse et sur des asphaltènes déposés sur de la silice ont été déterminés par analyse chromatographique frontale à 293, 298, 303 et 308 K. L'adsorption sur des asphaltènes floculés en masse était la plus importante avec des isothermes correspondant à un mécanisme de Freundlich. La quantité élevée de phénols adsorbés suggère une migration possible des molécules du phénol à travers la structure peu compacte des asphaltènes. Les isothermes observés dans le cas de silice tapissée d'asphaltènes ont montré que l'adsorption se produit en deux étapes correspondant probablement à deux organisations différentes des molécules de soluté à la surface.

  9. Terrestrial Planet Formation in the Presence of Migrating Super-Earths

    Science.gov (United States)

    Izidoro, André; Morbidelli, Alessandro; Raymond, Sean N.

    2014-11-01

    Super-Earths with orbital periods less than 100 days are extremely abundant around Sun-like stars. It is unlikely that these planets formed at their current locations. Rather, they likely formed at large distances from the star and subsequently migrated inward. In this work we use N-body simulations to study the effect of super-Earths on the accretion of rocky planets. In our simulations, one or more super-Earths migrates inward through a disk of Moon-size to Mars-size protoplanetary embryos and much smaller planetesimals embedded in a gaseous disk. In order to qualitatively cover possible scenarios of type-I migration for super-Earths, we have performed simulations considering many different migration speeds and configurations for these bodies. Fast-migrating super-Earths, where super-Earth’s migration is comparable to the traditional type-I isothermal regime (τmig˜0.01-0.1 Myr), only have a modest effect on the protoplanetary embryos and planetesimals. Sufficient material survives to form rocky, Earth-like planets on orbits exterior to the super-Earths'. In contrast, slowly-migrating super-Earths shepherd rocky material interior to their orbits and strongly deplete the terrestrial planet-forming zone. In this situation any Earth-sized planets in the habitable zone are extremely volatile-rich and are therefore probably not Earth-like.

  10. A simple isothermal DNA amplification method to screen black flies for Onchocerca volvulus infection.

    Science.gov (United States)

    Alhassan, Andy; Makepeace, Benjamin L; LaCourse, Elwyn James; Osei-Atweneboana, Mike Y; Carlow, Clotilde K S

    2014-01-01

    Onchocerciasis is a debilitating neglected tropical disease caused by infection with the filarial parasite Onchocerca volvulus. Adult worms live in subcutaneous tissues and produce large numbers of microfilariae that migrate to the skin and eyes. The disease is spread by black flies of the genus Simulium following ingestion of microfilariae that develop into infective stage larvae in the insect. Currently, transmission is monitored by capture and dissection of black flies and microscopic examination of parasites, or using the polymerase chain reaction to determine the presence of parasite DNA in pools of black flies. In this study we identified a new DNA biomarker, encoding O. volvulus glutathione S-transferase 1a (OvGST1a), to detect O. volvulus infection in vector black flies. We developed an OvGST1a-based loop-mediated isothermal amplification (LAMP) assay where amplification of specific target DNA is detectable using turbidity or by a hydroxy naphthol blue color change. The results indicated that the assay is sensitive and rapid, capable of detecting DNA equivalent to less than one microfilaria within 60 minutes. The test is highly specific for the human parasite, as no cross-reaction was detected using DNA from the closely related and sympatric cattle parasite Onchocerca ochengi. The test has the potential to be developed further as a field tool for use in the surveillance of transmission before and after implementation of mass drug administration programs for onchocerciasis.

  11. A simple isothermal DNA amplification method to screen black flies for Onchocerca volvulus infection.

    Directory of Open Access Journals (Sweden)

    Andy Alhassan

    Full Text Available Onchocerciasis is a debilitating neglected tropical disease caused by infection with the filarial parasite Onchocerca volvulus. Adult worms live in subcutaneous tissues and produce large numbers of microfilariae that migrate to the skin and eyes. The disease is spread by black flies of the genus Simulium following ingestion of microfilariae that develop into infective stage larvae in the insect. Currently, transmission is monitored by capture and dissection of black flies and microscopic examination of parasites, or using the polymerase chain reaction to determine the presence of parasite DNA in pools of black flies. In this study we identified a new DNA biomarker, encoding O. volvulus glutathione S-transferase 1a (OvGST1a, to detect O. volvulus infection in vector black flies. We developed an OvGST1a-based loop-mediated isothermal amplification (LAMP assay where amplification of specific target DNA is detectable using turbidity or by a hydroxy naphthol blue color change. The results indicated that the assay is sensitive and rapid, capable of detecting DNA equivalent to less than one microfilaria within 60 minutes. The test is highly specific for the human parasite, as no cross-reaction was detected using DNA from the closely related and sympatric cattle parasite Onchocerca ochengi. The test has the potential to be developed further as a field tool for use in the surveillance of transmission before and after implementation of mass drug administration programs for onchocerciasis.

  12. A simple isothermal DNA amplification method to screen black flies for Onchocerca volvulus infection.

    Science.gov (United States)

    Alhassan, Andy; Makepeace, Benjamin L; LaCourse, Elwyn James; Osei-Atweneboana, Mike Y; Carlow, Clotilde K S

    2014-01-01

    Onchocerciasis is a debilitating neglected tropical disease caused by infection with the filarial parasite Onchocerca volvulus. Adult worms live in subcutaneous tissues and produce large numbers of microfilariae that migrate to the skin and eyes. The disease is spread by black flies of the genus Simulium following ingestion of microfilariae that develop into infective stage larvae in the insect. Currently, transmission is monitored by capture and dissection of black flies and microscopic examination of parasites, or using the polymerase chain reaction to determine the presence of parasite DNA in pools of black flies. In this study we identified a new DNA biomarker, encoding O. volvulus glutathione S-transferase 1a (OvGST1a), to detect O. volvulus infection in vector black flies. We developed an OvGST1a-based loop-mediated isothermal amplification (LAMP) assay where amplification of specific target DNA is detectable using turbidity or by a hydroxy naphthol blue color change. The results indicated that the assay is sensitive and rapid, capable of detecting DNA equivalent to less than one microfilaria within 60 minutes. The test is highly specific for the human parasite, as no cross-reaction was detected using DNA from the closely related and sympatric cattle parasite Onchocerca ochengi. The test has the potential to be developed further as a field tool for use in the surveillance of transmission before and after implementation of mass drug administration programs for onchocerciasis. PMID:25299656

  13. ILO - International Migration Programme.

    Science.gov (United States)

    Boudraa, Miriam

    2011-01-01

    In a wide International Context characterised not only by the economical development but also by the social, cultural, political and individual development, we witness more and more to a exchange between the developed and the developing countries, which can be translated especially in the migration of the work force. In theory, all countries are either countries of origin either countries of transit or destination, and they are all responsible for the rights of migrant workers by promoting the rights, by monitoring and by preventing the abusive conditions. The process of migration of the workforce can be divided into three stages: the first coincides with the period prior to departure, the second is represented by the aftermath of the departure and the period of stay in the country of destination, the third stage corresponds to the return in the country of origin. The workers must be protected throughout this process by the international organizations that perform the catalytic role of communication and exchange between countries, for the only purpose of protecting the rights of immigrant and/or immigrants workers. The responsibility for the protection of workers is divided among the various players in the International Labour Organisation. Every country has to apply measures according to the international standards regarding workers' rights, standards that guide the various countries in the formulation and implementation of their policies and legislation. These standards are suggested by International Conventions, the ILO Conventions and other international instruments such as the human rights instrument. There has been a big step forward once the ILO Fundamental Conventions and Conventions on Migrant Workers where implemented and this implementation represented the use of the Guidelines "ILO Multilateral Framework on Labour Migration". PMID:22073693

  14. ILO - International Migration Programme.

    Science.gov (United States)

    Boudraa, Miriam

    2011-01-01

    In a wide International Context characterised not only by the economical development but also by the social, cultural, political and individual development, we witness more and more to a exchange between the developed and the developing countries, which can be translated especially in the migration of the work force. In theory, all countries are either countries of origin either countries of transit or destination, and they are all responsible for the rights of migrant workers by promoting the rights, by monitoring and by preventing the abusive conditions. The process of migration of the workforce can be divided into three stages: the first coincides with the period prior to departure, the second is represented by the aftermath of the departure and the period of stay in the country of destination, the third stage corresponds to the return in the country of origin. The workers must be protected throughout this process by the international organizations that perform the catalytic role of communication and exchange between countries, for the only purpose of protecting the rights of immigrant and/or immigrants workers. The responsibility for the protection of workers is divided among the various players in the International Labour Organisation. Every country has to apply measures according to the international standards regarding workers' rights, standards that guide the various countries in the formulation and implementation of their policies and legislation. These standards are suggested by International Conventions, the ILO Conventions and other international instruments such as the human rights instrument. There has been a big step forward once the ILO Fundamental Conventions and Conventions on Migrant Workers where implemented and this implementation represented the use of the Guidelines "ILO Multilateral Framework on Labour Migration".

  15. Population, desertification, and migration.

    Science.gov (United States)

    Westing, A H

    1994-01-01

    When an imbalance develops between population numbers and the carrying capacity of the land, the persons thereby displaced are referred to as environmental refugees. The utilization of the land beyond sustainability leads to land degradation and ultimately, desertification. The social and political impacts of long-term environmental migration can be distinguished: a) at the site of origin of the displaced persons by the residual population; b) at rural sites of destination within the nation between the new arrivals and preestablished populations; c) in the cities within the nation; d) in the nonindustrialized foreign countries; and e) in the industrialized foreign countries. In the event that an area which had previously been devoted to pastoralism is converted to agriculture, the displaced pastoralists might respond through armed rebellion. In some instances, the disenchanted urban squatters become a politically restive and even a destabilizing force, as occurred in Sudan in the 1980s, especially in Khartoum and Port Sudan. The foreign countries to which many of the displaced persons are migrating are subjected to increasing levels of migrant-induced economic, cultural, and political strains. The growing problems associated with south-to-north migration across the Mediterranean Sea have recently led France, Italy, Portugal, and Spain to enter into a consultative arrangement with Algeria, Libya, Mauritania, Morocco, and Tunisia. All foreign aid to the nonindustrialized countries that attempts to ameliorate the problem of desertification must adopt integrated approaches that: a) address population issues; b) support environmental education; c) provide for the protection of biodiversity; d) encourage participatory forms of local and national government; e) provide opportunities for income generation outside the livestock sector; and f) foster political security and facilitate ecogeographical (subregional) cooperation.

  16. Turkish migration in Europe: EU accession and migration flows

    OpenAIRE

    Wadim Strielkowski; Ondřej Glazar

    2014-01-01

    This paper analyses the impact of Turkey's potential EU membership on emigration from Turkey to the European Union. We apply panel data estimators using the data on emigration from EU15 countries into Germany and the Netherlands in order to construct possible future scenarios of Turkish migration to the EU. Three scenarios of migration, pessimistic, realistic and optimistic (depending on the fears related to the expected impact of Turkish migration on the EU labour markets), are drawn and fut...

  17. The migration flux: Understanding international immigration through internal migration

    OpenAIRE

    Rickard Sandell

    2011-01-01

    This paper introduces the idea that the network structure that emerges from a foreign-born population's internal migration process changes the conditions for international immigration. The idea is tested by using data from the period between 1998 and 2008 about virtually all internal and international migration events in Spain. The findings show that internal migration changes the intensity and the quality content of immigrant social capital transfers, with both positive and negative ramifica...

  18. Effects of fluvial processes in different order river valleys on redistribution and storage of particle-bound radioactive caesium-137 in area of significant Chernobyl fallout and impact on linked rivers with lower contamination levels

    Science.gov (United States)

    Belyaev, Vladimir; Golosov, Valentin; Shamshurina, Evgeniya; Ivanov, Maxim; Ivanova, Nadezhda; Bezukhov, Dmitry; Onda, Yuichi; Wakiyama, Yoshifumi; Evrard, Olivier

    2015-04-01

    Detailed investigations of the post-fallout fate of radionuclide contamination represent an important task in terms of environmental quality assessment. In addition, particle-bound radionuclides such as the most widespread anthropogenic isotope caesium-137 can be used as tracers for quantitative assessment of different sediment redistribution processes. In landscapes of humid plains with agriculture-dominated land use the post-fallout redistribution of caesium-137 is primarily associated with fluvial activity of various scales in cascade systems starting from soil erosion on cultivated hillslopes through gully and small dry valley network into different order perennial streams and rivers. Our investigations in the so-called Plavsk hotspot (area of very high Chernobyl caesium-137 contamination within the Plava River basin, Tula Region, Central European Russia) has been continuing for more than 15 years by now, while the time passed since the Chernobyl disaster and associated radioactive fallout (1986) is almost 29 years. Detailed information on the fluvial sediment and associated caesium-137 redistribution has been obtained for case study sites of different size from individual cultivated slopes and small catchments of different size (2-180 km2) to the entire Plava River basin scale (1856 km2). It has been shown that most of the contaminated sediment over the time passed since the fallout has remained stored within the small dry valleys of the 1-4 Hortonian order and local reservoirs (>70%), while only about 5% reached the 5-6 order valleys (main tributaries of the Plava River) and storage of the Plava floodplain itself represents as low as 0.3% of the basin-scale total sediment production from eroded cultivated hillslopes. Nevertheless, it has been shown that contaminated sediment yield from the Plava River basin exerts significant influence on less polluted downstream-linked river system. Recent progress of the investigations involved sampling of 7 detailed depth

  19. Migration of liquid phase from the primary/peritectic interface in a temperature gradient

    Science.gov (United States)

    Peng, Peng; Li, XinZhong; Su, YanQing; Guo, JingJie

    2016-07-01

    The migration of the liquid droplets from the primary α/peritectic β interface at the peritectic temperature TP has been observed and analyzed in a Sn-Ni peritectic alloy. During the isothermal annealing stage of the interrupted directional solidification, a concentration gradient is established across the liquid droplets along the direction of the temperature gradient due to the temperature gradient zone melting. Simultaneous remelting/resolidification at the top/bottom of the liquid droplets by this concentration gradient have been confirmed to lead to migration of these droplets towards higher temperatures. The dependence of the migration distance of the liquid droplets on isothermal annealing time has been well predicted. Furthermore, since the lengths of the liquid droplet are not uniform along the direction of the temperature gradient, the remelting/resolidification rates which are dependent on the local morphology of liquid droplet are different at different local positions of the liquid droplets. It has been demonstrated that the morphology of the liquid droplet was also influenced by the morphologies of the liquid phase themselves. Therefore, the morphology of the liquid droplet itself changes from spherical to some kinds of irregular shapes during its migration.

  20. Network migration for printers

    CERN Multimedia

    2016-01-01

    Further to the recent General Purpose (office) Network reorganisation (as announced in the Bulletin - see here), please note that the majority of print devices will be automatically migrated to the new network IP address range on Tuesday 27 September.   This change should be transparent for these devices and therefore end-users, provided you have installed the printers from the Print Service website. A small number of devices will require manual intervention from the Printer Support team in order to migrate correctly. These devices will not change their IP address until the manual intervention, which will be carried out before Monday 3rd October. However, if you have mistakenly connected directly to the printer’s IP address, then your printing will be affected – please uninstall the printer (for help, see: KB3785), and re-install it from the Print Service website (or follow instructions for visitor machines). Please do this as soon as possible in order to avoid printing issues, t...

  1. Palaearctic-African Bird Migration

    DEFF Research Database (Denmark)

    Iwajomo, Soladoye Babatola

    Bird migration has attracted a lot of interests over past centuries and the methods used for studying this phenomenon has greatly improved in terms of availability, dimension, scale and precision. In spite of the advancements, relatively more is known about the spring migration of trans......-Saharan migrants than autumn migration. Information about the behavior and interactions of migrants during the nonbreeding season in sub-Saharan Africa is also scarce for many species. Furthermore, very little is known about intra-African migration. This thesis summarizes my research on the autumn migration...... of birds from Europe to Africa and opens up the possibility of studying intra-African migration. I have used long-term, standardized autumn ringing data from southeast Sweden to investigate patterns in biometrics, phenology and population trends as inferred from annual trapping totals. In addition, I...

  2. Modelling Turkish Migration to Germany

    OpenAIRE

    Akkoyunlu, Sule; Siliverstovs, Boriss

    2006-01-01

    This study develops a time series model of Turkish migration to Germany for the period 1963-2004 using the cointegration technique. A single cointegrating relation between the migration flow variable and the relative income ratio between Germany and Turkey, the unemployment rates in Germany and Turkey, and the trade variable, that captures intensity of bilateral economic cooperation, is found. By including the trade variable in the empirical migration function we investigate whether trade and...

  3. Migration and the Demographic Shift

    OpenAIRE

    Zaiceva, Anzelika; Zimmermann, Klaus F.

    2014-01-01

    This chapter connects population aging with international migration. After documenting the trends for both, we review the supply-push and demand-pull determinants of migration, focusing particularly on the role of age and aging. We subsequently discuss the literature concerning the implications of migration in the context of aging for labor markets, health and public budgets including the political economy context. Although immigration is sometimes suggested as a solution for the aging proble...

  4. The challenges of managing migration

    Energy Technology Data Exchange (ETDEWEB)

    Tacoli, Cecilia

    2005-10-15

    Migration and urbanisation are driven by economic growth and social change, but also by deepening inequalities. Managing migration should not be equated with curbing it, as this inevitably reduces migrants' rights. But managing population movement whilst respecting the rights of migrants and nonmigrants, supporting the contribution of migration to poverty reduction and economic growth in sending and receiving areas and reducing the human and material costs of movement means that fundamental challenges need to be addressed.

  5. Gender and Migration: Overview Report

    OpenAIRE

    Jolly, Susie; Reeves, Hazel; Piper, Nicola

    2005-01-01

    Abstract. Over the past four decades total numbers of international migrants have more than doubled but the percentage of the world population migrating has remained fairly constant. There are now 175 million international migrants worldwide or approximately 3.5 per cent of the global population – about half of whom are women, despite the common misconception that men are the migrants. This Overview Report on Gender and Migration takes a broad approach to migration – it looks at the gender dy...

  6. Sensitivity of the modelled deposition of Caesium-137 from the Fukushima Dai-ichi nuclear power plant to the wet deposition parameterisation in NAME

    International Nuclear Information System (INIS)

    This paper describes an investigation into the impact of different meteorological data sets and different wet scavenging coefficients on the model predictions of radionuclide deposits following the accident at the Fukushima Dai-ichi nuclear power plant in March 2011. Three separate operational meteorological data sets, the UK Met Office global meteorology, the ECMWF global meteorology and the Japan Meteorological Agency (JMA) mesoscale meteorology as well as radar rainfall analyses from JMA were all used as inputs to the UK Met Office's dispersion model NAME (the Numerical Atmospheric-dispersion Modelling Environment). The model predictions of Caesium-137 deposits based on these meteorological models all showed good agreement with observations of deposits made in eastern Japan with correlation coefficients ranging from 0.44 to 0.80. Unexpectedly the NAME run using radar rainfall data had a lower correlation coefficient (R = 0.66), when compared to observations, than the run using the JMA mesoscale model rainfall (R = 0.76) or the run using ECMWF met data (R = 0.80). Additionally the impact of modifying the wet scavenging coefficients used in the parameterisation of wet deposition was investigated. The results showed that modifying the scavenging parameters had a similar impact to modifying the driving meteorology on the rank calculated from comparing the modelled and observed deposition

  7. [Comparison of the ability to fertilize females by Hyalomma anatolicum anatolicum males irradiated with gamma radiation from caesium 137 with non-irradiated males].

    Science.gov (United States)

    Karaer, Zafer; Kar, Sirri; Düzgün, Ali; Güven, Esin; Cakmak, Ayşe; Emre, Zişan; Nalbantoğlu, Serpil; Saribaş, Taner; Akçay, Aytaç

    2009-01-01

    In this study, Hyalomma anatolicum anatolicum male ticks were subjected to gamma radiation with a dose of 10 Gy emitted by a gamma-ray source of Caesium 137. Female ticks were divided into 3 groups and placed in rabbit ears to feed. In the first group, the females fed with normal and irradiated males, in the second group females fed only with irradiated males and in last group females fed with normal males. Biological parameters such as the feeding period, weights, period of time from dropping until egg-laying began, the number of eggs and the number of larva hatching from eggs were recorded. With the results of statistical analysis it was found that the average egg laying period of females in the second group was clearly less (22.77 days) than other groups and the difference between these groups was statistically important (P < 0.05). After evaluation of numbers of larva, also there was a statistically important difference between the groups and the average number of larva was clearly higher (2519.30) in third group than other groups. In conclusion, in this study it was found that irradiated males could not compete with normal males in mating with females and because of this they couldn't affect the feeding and reproductivity of females.

  8. Sensitivity of the modelled deposition of Caesium-137 from the Fukushima Dai-ichi nuclear power plant to the wet deposition parameterisation in NAME.

    Science.gov (United States)

    Leadbetter, Susan J; Hort, Matthew C; Jones, Andrew R; Webster, Helen N; Draxler, Roland R

    2015-01-01

    This paper describes an investigation into the impact of different meteorological data sets and different wet scavenging coefficients on the model predictions of radionuclide deposits following the accident at the Fukushima Dai-ichi nuclear power plant in March 2011. Three separate operational meteorological data sets, the UK Met Office global meteorology, the ECMWF global meteorology and the Japan Meteorological Agency (JMA) mesoscale meteorology as well as radar rainfall analyses from JMA were all used as inputs to the UK Met Office's dispersion model NAME (the Numerical Atmospheric-dispersion Modelling Environment). The model predictions of Caesium-137 deposits based on these meteorological models all showed good agreement with observations of deposits made in eastern Japan with correlation coefficients ranging from 0.44 to 0.80. Unexpectedly the NAME run using radar rainfall data had a lower correlation coefficient (R = 0.66), when compared to observations, than the run using the JMA mesoscale model rainfall (R = 0.76) or the run using ECMWF met data (R = 0.80). Additionally the impact of modifying the wet scavenging coefficients used in the parameterisation of wet deposition was investigated. The results showed that modifying the scavenging parameters had a similar impact to modifying the driving meteorology on the rank calculated from comparing the modelled and observed deposition. PMID:24745690

  9. Microhydration of caesium compounds: Cs, CsOH, CsI and Cs₂I₂ complexes with one to three H₂O molecules of nuclear safety interest.

    Science.gov (United States)

    Sudolská, Mária; Cantrel, Laurent; Cernušák, Ivan

    2014-04-01

    Structure and thermodynamic properties (standard enthalpies of formation and Gibbs free energies) of hydrated caesium species of nuclear safety interest, Cs, CsOH, CsI and its dimer Cs₂I₂, with one up to three water molecules, are calculated to assess their possible existence in severe accident occurring to a pressurized water reactor. The calculations were performed using the coupled cluster theory including single, double and non-iterative triple substitutions (CCSD(T)) in conjunction with the basis sets (ANO-RCC) developed for scalar relativistic calculations. The second-order spin-free Douglas-Kroll-Hess Hamiltonian was used to account for the scalar relativistic effects. Thermodynamic properties obtained by these correlated ab initio calculations (entropies and thermal capacities at constant pressure as a function of temperature) are used in nuclear accident simulations using ASTEC/SOPHAEROS software. Interaction energies, standard enthalpies and Gibbs free energies of successive water molecules addition determine the ordering of the complexes. CsOH forms the most hydrated stable complexes followed by CsI, Cs₂I₂, and Cs. CsOH still exists in steam atmosphere even at quite high temperature, up to around 1100 K.

  10. Accumulation of potassium, rubidium and caesium (133Cs and 137Cs) in various fractions of soil and fungi in a Swedish forest

    International Nuclear Information System (INIS)

    Radiocaesium (137Cs) was widely deposited over large areas of forest in Sweden as a result of the Chernobyl accident in 1986 and many people in Sweden eat wild fungi and game obtained from these contaminated forests. In terms of radioisotope accumulation in the food chain, it is well known that fungal sporocarps efficiently accumulate radiocaesium (137Cs), as well as the alkali metals potassium (K), rubidium (Rb) and caesium (Cs). The fungi then enhance uptake of these elements into host plants. This study compared the accumulation of these three alkali metals in bulk soil, rhizosphere, soil-root interface, fungal mycelium and sporocarps of mycorrhizal fungi in a Swedish forest. The soil-root interface was found to be distinctly enriched in K and Rb compared with the bulk soil. Potassium concentrations increased in the order: bulk soil 137Cs could be prevented by providing additional Rb or K at contaminated sites. The levels of K, Rb, and Cs found in sporocarps were at least one order of magnitude higher than those in fungal mycelium. These results provide new insights into the use of transfer factors or concentration ratios. The final step, the transfer of alkali metals from fungal mycelium to sporocarps, raised some specific questions about possible mechanisms.

  11. The Migration of Highly Skilled Asian Workers

    OpenAIRE

    Horáková, Jana

    2012-01-01

    This thesis is focused on migration of highly skilled workforce. The aim of this work to show current migration flows of highly skilled workers and particularly flows of highly skilled Asian migrants. First chapter explains migration terms and examines highly skilled migration causes through migration theories. Second chapter studies international migration flows and their long-term development. Last chapter is focused on migration flows of highly skilled Asians to OECD countries and within A...

  12. Microstructure evolution and deformation mechanisms of the electroslag refined-continuous directionally solidified (ESR-CDS®) superalloy Rene88DT during isothermal compression

    International Nuclear Information System (INIS)

    The microstructure evolution and deformation mechanisms of alloy Rene88DT prepared by ESR-CDS® during isothermal compression have been investigated by optical microscopy (OM), electron back scattered diffraction (EBSD) and transmission electron microscopy (TEM). The results showed that two cycles of dynamic recrystallization (DRX) occurred during the compressive deformation of the sample at super-solvus temperature with total true strain of 1.2, and this led to a near completely recrystallized fine-grained microstructure. For samples deformed at sub-solvus temperature, only one cycle of DRX occurred during compression with total true strain of 1.2, resulting in a partial recrystallized microstructure, and large misorientation formed in the un-recrystallized coarse grains. DRX is mainly initiated at the columnar grain boundaries or stimulated by the carbide particles within the grains. The main DRX mechanisms are grain boundary bulging and migration, second phase particles stimulation, sub-grain coarsening and migration

  13. Microstructure evolution and deformation mechanisms of the electroslag refined-continuous directionally solidified (ESR-CDS{sup ®}) superalloy Rene88DT during isothermal compression

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Rui [Superalloys Department, Central Iron & Steel Research Institute, Beijing 100081 (China); Li, Fulin, E-mail: lifulin1016@sina.com [Superalloys Department, Central Iron & Steel Research Institute, Beijing 100081 (China); Yin, Fajie; Feng, Di; Tian, Zhiling [Superalloys Department, Central Iron & Steel Research Institute, Beijing 100081 (China); Chang, Litao [School of Materials Science and Engineering, Xi' an University of Technology, Xi' an 710048 (China)

    2015-06-25

    The microstructure evolution and deformation mechanisms of alloy Rene88DT prepared by ESR-CDS{sup ®} during isothermal compression have been investigated by optical microscopy (OM), electron back scattered diffraction (EBSD) and transmission electron microscopy (TEM). The results showed that two cycles of dynamic recrystallization (DRX) occurred during the compressive deformation of the sample at super-solvus temperature with total true strain of 1.2, and this led to a near completely recrystallized fine-grained microstructure. For samples deformed at sub-solvus temperature, only one cycle of DRX occurred during compression with total true strain of 1.2, resulting in a partial recrystallized microstructure, and large misorientation formed in the un-recrystallized coarse grains. DRX is mainly initiated at the columnar grain boundaries or stimulated by the carbide particles within the grains. The main DRX mechanisms are grain boundary bulging and migration, second phase particles stimulation, sub-grain coarsening and migration.

  14. New Exact Solutions for Isothermal Magnetostatic Atmosphere Equations

    Directory of Open Access Journals (Sweden)

    Mohamed Tawfik ATTIA

    2014-12-01

    Full Text Available Here, an extended, (G'/G-expansion method with a computerized symbolic computation is used for constructing the exact travelling wave solutions for isothermal magnetostatic atmospheres equations. These equations depend on arbitrary functions that must be specified with choices of the different choice of the different arbitrary functions. The proposed method has been successfully used to obtain some exact travelling wave solutions for the Liouville and sinh-Poisson equations. The obtained travelling wave solutions are expressed by hyperbolic, triangular and exponential function. The solutions obtained via the propose method have many potential applications in physics.

  15. Isothermal crystallization kinetic modeling of poly(etherketoneketone) (PEKK)

    Science.gov (United States)

    Choupin, T.; Paris, C.; Cinquin, J.; Fayolle, B.; Régnier, G.

    2016-05-01

    Isothermal melt and cold crystallization kinetics of poly(etherketoneketone) (PEKK) have been investigated by differential scanning calorimetry. A modified Avrami model has been used to describe the two-stage crystallization of PEKK. The primary crystallization stage is assumed to be a two dimensional nucleation growth with an Avrami exponent of 2 whereas the secondary stage is assumed to be a one dimensional nucleation growth with an Avrami exponent of 1. The evolution of the crystallization constant rates depending on temperature has been modeled with the Hoffman and Lauritzen growth equation. The activation energy of nucleation constants Kg for both crystallizations are presented.

  16. Isothermal Melt Crystallization Kinetics of PP/organoclay Blends

    Directory of Open Access Journals (Sweden)

    Wang Kunyan

    2016-01-01

    Full Text Available Polystyrene (PP/organoclay (OMMT blends were prepared by co-rotating twin-screw extruder. The effects of OMMT on isothermal crystallization behaviors of blends was studied by differential scanning calorimetry (DSC. Using Avrami equation analysis the crystallization kinetics of materials. The analysis result shows that the OMMT act as effective nucleating agents, accelerating the crystallization of PP, then lead the rate of crystallization increased. Avrami exponent n is between 2.04~3.57, which indicating that PP/OMMT blends crystallization process might correspond to a two-dimensional or three-dimensional growth process. The activation enerigies for isotheraml crystallization were determined by the Arrhenius equation.

  17. The density variance -- Mach number relation in supersonic, isothermal turbulence

    OpenAIRE

    Price, Daniel J.; Federrath, Christoph; Brunt, Christopher M.

    2010-01-01

    We examine the relation between the density variance and the mean-square Mach number in supersonic, isothermal turbulence, assumed in several recent analytic models of the star formation process. From a series of calculations of supersonic, hydrodynamic turbulence driven using purely solenoidal Fourier modes, we find that the `standard' relationship between the variance in the log of density and the Mach number squared, i.e., sigma^2_(ln rho/rhobar)=ln (1+b^2 M^2), with b = 1/3 is a good fit ...

  18. Isothermal plasma waves in a gravitomagnetic planar analog

    International Nuclear Information System (INIS)

    We investigate the wave properties of the Kerr black hole with isothermal plasma using 3+1 ADM formalism. The corresponding Fourier-analyzed perturbed GRMHD equations are used to obtain the dispersion relations. These relations lead to the real values of the components of the wave vector k which are used to evaluate quantities such as phase and group velocities etc. These have been discussed graphically in the neighborhood of the pair production region. The results obtained verify the conclusion of Mackay et al according to which rotation of a black hole is required for negative phase velocity propagation

  19. Isothermal, isobaric, elevated temperature, high-pressure, flow calorimeter

    Science.gov (United States)

    Christensen, J. J.; Hansen, L. D.; Izatt, R. M.; Eatough, D. J.; Hart, R. M.

    1981-08-01

    An isothermal, isobaric, flow calorimeter suitable for measuring either endothermic or exothermic heats of mixing from 273 to 423 K and from 0.1 to 40.5 MPa is described. Energy effects from 0.15 to 30 J/min can be measured to an accuracy of ±0.5% for standard test systems at a constant temperature through the use of an automatically controlled heater and a constant cooling Peltier device. The calorimeter was tested by measuring the heat of mixing of water-ethanol at 383 K and 1 MPa and was found to produce data in good agreement with published literature values.

  20. Isothermal Titration Calorimetry: Assisted Crystallization of RNA-Ligand Complexes.

    Science.gov (United States)

    Da Veiga, Cyrielle; Mezher, Joelle; Dumas, Philippe; Ennifar, Eric

    2016-01-01

    The success rate of nucleic acids/ligands co-crystallization can be significantly improved by performing preliminary biophysical analyses. Among suitable biophysical approaches, isothermal titration calorimetry (ITC) is certainly a method of choice. ITC can be used in a wide range of experimental conditions to monitor in real time the formation of the RNA- or DNA-ligand complex, with the advantage of providing in addition the complete binding profile of the interaction. Following the ITC experiment, the complex is ready to be concentrated for crystallization trials. This chapter describes a detailed experimental protocol for using ITC as a tool for monitoring RNA/small molecule binding, followed by co-crystallization.

  1. Modeling Cavitation in ICE Pistons Made with Isothermal Forging

    Directory of Open Access Journals (Sweden)

    V.V. Astanin

    2014-07-01

    Full Text Available Possible causes for cavitations in parts made with an Al-Si eutectic alloy AK12D (AlSi12 were explored with mathematical and physical modeling with involved acoustic emission. Pores were formed from micro-cracks, which appear during the early stages of a deformation process, with the help of micro-stresses appearing at phase boundaries (Al/Si interface due to thermal expansion. At the design stage of isothermal forgings of such products it is recommended to provide a scheme of the deformed shape, which is under uniform compression, to compensate for the inter-phase stresses.

  2. Non-isothermal plasticity model for cyclic behaviour of soils.

    OpenAIRE

    Laloui, L.; Cekerevac, C.

    2008-01-01

    On the one hand, it has been observed that liquefaction- induced shear deformation of soils accumulates in a cycle- by-cycle pattern. On the other hand, it is known that heating could induce plastic hardening. This study deals with the constitutive modelling of the effect that heat may have on the cyclic mechanical properties of cohesive soils, a relatively new area of interest in soil mechanics. In this paper, after a presentation of the thermo-mechanical framework, a non-isothermal pl...

  3. Modeling of the Adiabatic and Isothermal Methanation Process

    Science.gov (United States)

    Porubova, Jekaterina; Bazbauers, Gatis; Markova, Darja

    2011-01-01

    Increased use of biomass offers one of the ways to reduce anthropogenic impact on the environment. Using various biomass conversion processes, it is possible to obtain different types of fuels: • solid, e.g. bio-carbon; • liquid, e.g. biodiesel and ethanol; • gaseous, e.g. biomethane. Biomethane can be used in the transport and energy sector, and the total methane production efficiency can reach 65%. By modeling adiabatic and isothermal methanation processes, the most effective one from the methane production point of view is defined. Influence of the process parameters on the overall efficiency of the methane production is determined.

  4. The oxidation kinetics of zircaloy - 4 under isothermal conditions

    International Nuclear Information System (INIS)

    The oxidation kinetics of zircaloy-4 tubes was studied by means of isothermal tests in the temperature interval 5000C to 9000C. Dry oxygen and water steam, were used as oxidant agents. The results show that the oxidation kinetics law exhibits a behaviour from cubic to parabolic in the range of the time and temperatures of the experiment. Dry oxygen shows a stronger oxidation effect than water steam. A special mechanical test to study the embrittlement effect in the small samples of zircaloy tubes was used. (Author)

  5. Generalized isothermal models with strange equation of state

    Indian Academy of Sciences (India)

    S D Maharaj; S Thirukkanesh

    2009-03-01

    We consider the linear equation of state for matter distributions that may be applied to strange stars with quark matter. In our general approach the compact relativistic body allows for anisotropic pressures in the presence of the electromagnetic field. New exact solutions are found to the Einstein–Maxwell system. A particular case is shown to be regular at the stellar centre. In the isotropic limit we regain the general relativistic isothermal Universe. We show that the mass corresponds to the values obtained previously for quark stars when anisotropy and charge are present.

  6. RuO2 Non-isothermal Thermometry

    Science.gov (United States)

    Ventura, Guglielmo; Giomi, Silvia

    2016-08-01

    The use of a RuO2 resistor in non-isothermal measuring setup is proposed. A calculation is presented to explain the principle for a resistor obeying variable-range-hopping theory and the results are compared to measurements in the range of 11.2-30 mK for a commercial resistor. The thermometer, which measures the electron temperature, does not show overheating effects at 11.2 mK with a measuring power of 10^{-12} W.

  7. Patterns of East to West migration in the context of European migration systems possibilities and limits of migration control

    OpenAIRE

    Irina Molodikova

    2008-01-01

    This paper gives an overview of the main migration trends of the CIS (Commonwealth of Independent States) migration system in the context of the development of EU migration and migration control and seeks to explain the peculiarities of the CIS migration system’s development.

  8. Migration and women's health.

    Science.gov (United States)

    Adanu, Richard M K; Johnson, Timothy R B

    2009-08-01

    Women have been migrating at similar rates to men for the past 40 years, and comprised about half of all migrants in 2005. Women and children are most affected by displacement as a result of wars and human trafficking. In some cases, the health of female migrants is improved via integration into better health systems in the host country. More often, however, the health of female migrants is affected negatively. Women are doubly disadvantaged because they are discriminated against as women and as migrants. Female migrants are also highly vulnerable to acts of sexual abuse, rape, and violence. This is especially true for women in refugee camps, whose reproductive health needs are often overlooked. To improve the health of female migrants it is important to develop and implement policies that recognize and insist on the respect of the rights of migrants. PMID:19539929

  9. Kirchhoff migration without phases

    Science.gov (United States)

    Bardsley, Patrick; Guevara Vasquez, Fernando

    2016-10-01

    We present a simple, frequency domain, preprocessing step to Kirchhoff migration that allows the method to image scatterers when the wave field phase information is lost at the receivers, and only intensities are measured. The resulting imaging method does not require knowing the phases of the probing field or manipulating the phase of the wave field at the receivers. In a regime where the scattered field is small compared to the probing field, the problem of recovering the full-waveform scattered field from intensity data can be formulated as an embarrassingly simple least-squares problem. Although this only recovers the projection (on a known subspace) of the full-waveform scattered field, we show that, for high frequencies, this projection gives Kirchhoff images asymptotically identical to the images obtained with full waveform data. Our method can also be used when the source is modulated by a Gaussian process and autocorrelations are measured at an array of receivers.

  10. Nightly Test system migration

    CERN Document Server

    Win-Lime, Kevin

    2013-01-01

    The summer student program allows students to participate to the Cern adventure. They can follow several interesting lectures about particle science and participate to the experiment work. As a summer student, I had worked for LHCb experiment. LHCb uses a lot of software to analyze its data. All this software is organized in packages and projects. They are built and tested during the night using an automated system and the results are displayed on a web interface. Actually, LHCb is changing this system. It is looking for a replacement candidate. So I was charged to unify some internal interfaces to permit a swift migration. In this document, I will describe shortly the system used by LHCb, then I will explain what I have done in detail.

  11. Kirchhoff migration without phases

    CERN Document Server

    Bardsley, Patrick

    2016-01-01

    We present a simple, frequency domain, preprocessing step to Kirchhoff migration that allows the method to image scatterers when the wave field phase information is lost at the receivers, and only intensities are measured. The resulting imaging method does not require knowing the phases of the probing field or manipulating the phase of the wave field at the receivers. In a regime where the scattered field is small compared to the probing field, the problem of recovering the full-waveform scattered field from intensity data can be formulated as an embarrassingly simple least-squares problem. Although this only recovers the projection (on a known subspace) of the full-waveform scattered field, we show that, for high frequencies, this projection gives Kirchhoff images asymptotically identical to the images obtained with full waveform data. Our method can also be used when the source is modulated by a Gaussian process and autocorrelations are measured at an array of receivers.

  12. Fluid Flow and Mixing in Non-Isothermal Water Model of Continuous Casting Tundish

    Institute of Scientific and Technical Information of China (English)

    Mehdi ALIZADEH; Hossein EDRIS; Ali SHAFYEI

    2008-01-01

    Fluid flow and mixing of molten steel in a twin-slab-strand continuous casting tundish were investigated using a mixing model under non-isothermal conditions. This model led to a set of ordinary differential equations that were solved with a Runge-Kutta algorithm. Steady state water modeling was carried out under non-isothermal conditions. Experimental data obtained from the water model were used to calibrate the mixing model. Owing to the presence of a mixed convection in the non-isothermal conditions, a channelizing flow would be created in the fluid inside the tundish. A mixing model was designed that was capable of predicting RTD (residence time distribution) curves for different cases in non-isothermal conditions. The relationship between RTD parameters and the Tu (tundish Richardson number) was obtained for various cases under non-isothermal conditions. The results show that the RTD parameters were completely different under isothermal and non-isothermal conditions. The comparison of the RTD curves between the isothermal and non-isothermal conditions presents that the extent of mixing in the tundish in nonisothermal conditions is lower than the mixing extent in isothermal conditions.

  13. 3D Finite Element Analysis of Spider Non-isothermal Forging Process

    Science.gov (United States)

    Niu, Ling; Wei, Wei; Wei, Kun Xia; Alexandrov, Igor V.; Hu, Jing

    2016-06-01

    The differences of effective stress, effective strain, velocity field, and the load-time curves between the spider isothermal and non-isothermal forging processes are investigated by making full use of 3D FEA, and verified by the production experiment of spider forging. Effective stress is mainly concentrated on the pin, and becomes lower closer to the front of the pin. The maximum effective strain in the non-isothermal forging is lower than that in the isothermal. The great majority of strain in the non-isothermal forging process is 1.76, which is larger than the strain of 1.31 in the isothermal forging. The maximum load required in the isothermal forging is higher than that in the non-isothermal. The maximum experimental load and deformation temperature in the spider production are in good agreement with those in the non-isothermal FEA. The results indicate that the non-isothermal 3D FEA results can guide the design of the spider forging process.

  14. Migration in birds and fishes

    NARCIS (Netherlands)

    Verwey, J.

    1949-01-01

    Our knowledge concerning the periodical movements in animals called migrations is chiefly based on observations on birds. By and by, however, a number of facts concerning migration in other animal groups have been assembled and it seems worth while to compare them with those known for birds. There i

  15. Migrating foreign body from hypopharynx

    DEFF Research Database (Denmark)

    Mowinckel, Marius Storm; Charabi, Birgitte Wittenborg

    2014-01-01

    In this case report we present a 20-month-old girl with a migrating foreign body, a "smiley" sticker, that migrated from hypopharynx to surrounding tissue and created an abscess with a fistula, one year after ingestion. The foreign body was removed without difficulty under general anaesthesia, and...

  16. Ocean dynamic processes causing spatially heterogeneous distribution of sedimentary caesium-137 massively released from the Fukushima Daiichi Nuclear Power Plant

    Science.gov (United States)

    Higashi, H.; Morino, Y.; Furuichi, N.; Ohara, T.

    2015-12-01

    Massive amounts of anthropogenic radiocaesium 137Cs that were released into the environment by the Fukushima Daiichi Nuclear Power Plant accident in March 2011 are widely known to have extensively migrated to Pacific Ocean sediment off of eastern Japan. Several recent reports have stated that the sedimentary 137Cs is now stable with a remarkably heterogeneous distribution. The present study elucidates ocean dynamic processes causing this heterogeneous sedimentary 137Cs distribution in and around the shelf off Fukushima and adjacent prefectures. We performed a numerical simulation of oceanic 137Cs behaviour for about 10 months after the accident, using a comprehensive dynamic model involving advection-diffusion transport in seawater, adsorption and desorption to and from particulate matter, sedimentation and suspension on and from the bottom, and vertical diffusion transport in the sediment. A notable simulated result was that the sedimentary 137Cs significantly accumulated in a swath just offshore of the shelf break (along the 50-100 m isobath) as in recent observations, although the seabed in the entire simulation domain was assumed to have ideal properties such as identical bulk density, uniform porosity, and aggregation of particles with a single grain diameter. This result indicated that the heterogeneous sedimentary 137Cs distribution was not necessarily a result of the spatial distribution of 137Cs sediment adsorptivity. The present simulation suggests that the shape of the swath is mainly associated with spatiotemporal variation between bottom shear stress in the shallow shelf (< 50 m depths) and that offshore of the shelf break. In a large part of the shallow shelf, the simulation indicated that strong bottom friction suspending particulate matter from the seabed frequently occurred via a periodic spring tide about every 2 weeks and via occasional strong wind. The sedimentary 137Cs thereby could hardly stay on the surface of the seabed with the result that

  17. A New Potential-Density Pair for Isothermal Star Clusters

    CERN Document Server

    Stone, Nicholas C

    2015-01-01

    We present a new potential-density pair designed to model nearly isothermal star clusters (and similar self-gravitating systems) with a central core and an outer turnover radius, beyond which density falls off as $r^{-4}$. In the intermediate zone, the profile is similar to that of an isothermal sphere (density $\\rho \\propto r^{-2}$), somewhat less steep than the King 1962 profile, and with the advantage that many dynamical quantities can be written in a simple closed form. We derive analytic expressions for the cluster binding energy, central velocity dispersion, and escape velocity, and apply these to create toy models for cluster core collapse and evaporation. We rederive classical results for evaporating, collapsing, and quasi-equilibrium (heated) clusters, and fit our projected surface brightness profiles to observed globular and open clusters. We find that the quality of the fit is generally at least as good as that for the surface brightness profiles of King 1962. This model can be used for convenient ...

  18. Thermistor based, low velocity isothermal, air flow sensor

    International Nuclear Information System (INIS)

    The semiconductor thermistor technology is applied as a flow sensor to measure low isothermal air velocities (<2 ms−1). The sensor is subjected to heating and cooling cycles controlled by a multifunctional timer. In the heating stage, the alternating current of a main AC power supply source guarantees a uniform thermistor temperature distribution. The conditioning circuit assures an adequate increase of the sensors temperature and avoids the thermal disturbance of the flow. The power supply interruption reduces the consumption from the source and extends the sensors life time. In the cooling stage, the resistance variation of the flow sensor is recorded by the measuring chain. The resistive sensor parameters proposed vary significantly and feature a high sensitivity to the flow velocity. With the aid of a computer, the data transfer, storage and analysis provides a great advantage over the traditional local anemometer readings. The data acquisition chain has a good repeatability and low standard uncertainties. The proposed method measures isothermal air mean velocities from 0.1 ms−1 to 2 ms−1 with a standard uncertainty error less than 4%. (paper)

  19. Estimating Uranium Partition Coefficients from Laboratory Adsorption Isotherms

    International Nuclear Information System (INIS)

    An estimated 330 metric tons of uranium have been buried in the radioactive waste Subsurface Disposal Area (SDA) at the Idaho National Engineering and Environmental Laboratory (INEEL). An assessment of uranium transport parameters is being performed to decrease the uncertainty in risk and dose predictions derived from computer simulations of uranium fate and transport to the underlying Snake River Plain Aquifer. Uranium adsorption isotherms have been measured in the laboratory and fit with a Freundlich isotherm. The Freundlich n parameter was statistically identical for 14 sediment samples. The Freundlich Kf for seven samples, where material properties have been measured, is correlated to sediment surface area. Based on these empirical observations, a model has been derived for adsorption of uranium on INEEL sedimentary materials using surface complexation theory. The model was then used to predict the range of adsorption conditions to be expected at the SDA. Adsorption in the deep vadose zone is predicted to be stronger than in near-surface sediments because the total dissolved carbonate decreases with depth

  20. Isothermal titration calorimetry: A thermodynamic interpretation of measurements

    International Nuclear Information System (INIS)

    Highlights: ► Literature review shows that many ITC utilizations are based on empirical rules. ► A proper and rigorous thermodynamic interpretation of heats of titration is proposed. ► Heats of titration are independent of the cell type using infinitesimal titrations. ► Heats of interaction between solutes require only two different titration runs. - Abstract: Isothermal titration calorimeters have been developed and in use since the 1960s and the number of applications based on empirical rules to use them steadily increases. In this paper a rigorous study of the physical interpretation of the titration heat and the thermodynamic framework underlying isothermal titration calorimetry are proposed. For infinitesimal titrations, the titration heat is independent of the cell type employed, and the interpretation of the titration heat depends on the titrant composition and on the experiment type. Moreover, for the study of the interaction between two solutes in solution, only a combination of two experiments is necessary, and the result is interpreted as the partial enthalpy of interaction at infinite dilution of the solute contained in the titrant solution.

  1. Equivalent dose determination using a quartz isothermal TL signal

    DEFF Research Database (Denmark)

    Vandenberghe, D.A.G.; Jain, Mayank; Murray, A.S.

    2009-01-01

    We report on further developments in the use of an isothermal thermoluminescence (ITL) signal for determining the equivalent dose (De) in unheated sedimentary quartz. In order to minimise sensitivity change during the first measurement, the ITL signal is measured at 270 °C following a preheat at ...... the same age range as the OSL signal, and it appears especially advantageous for application to quartz samples for which the OSL signal saturates below 500 Gy.......We report on further developments in the use of an isothermal thermoluminescence (ITL) signal for determining the equivalent dose (De) in unheated sedimentary quartz. In order to minimise sensitivity change during the first measurement, the ITL signal is measured at 270 °C following a preheat...... signal can be fully reset by sunlight, and grows with dose over at least the same range as the OSL signal. A single-aliquot regenerative-dose (SAR) protocol can be used with this ITL signal. Dose recovery experiments confirm the suitability of the measurement protocol; the De values are in acceptable...

  2. Characterization of protein-protein interactions by isothermal titration calorimetry.

    Science.gov (United States)

    Velazquez-Campoy, Adrian; Leavitt, Stephanie A; Freire, Ernesto

    2015-01-01

    The analysis of protein-protein interactions has attracted the attention of many researchers from both a fundamental point of view and a practical point of view. From a fundamental point of view, the development of an understanding of the signaling events triggered by the interaction of two or more proteins provides key information to elucidate the functioning of many cell processes. From a practical point of view, understanding protein-protein interactions at a quantitative level provides the foundation for the development of antagonists or agonists of those interactions. Isothermal Titration Calorimetry (ITC) is the only technique with the capability of measuring not only binding affinity but the enthalpic and entropic components that define affinity. Over the years, isothermal titration calorimeters have evolved in sensitivity and accuracy. Today, TA Instruments and MicroCal market instruments with the performance required to evaluate protein-protein interactions. In this methods paper, we describe general procedures to analyze heterodimeric (porcine pancreatic trypsin binding to soybean trypsin inhibitor) and homodimeric (bovine pancreatic α-chymotrypsin) protein associations by ITC.

  3. Application and use of isothermal calorimetry in pharmaceutical development.

    Science.gov (United States)

    O'Neill, Michael A A; Gaisford, Simon

    2011-09-30

    There are many steps involved in developing a drug candidate into a formulated medicine and many involve analysis of chemical interaction or physical change. Calorimetry is particularly suited to such analyses as it offers the capacity to observe and quantify both chemical and physical changes in virtually any sample. Differential scanning calorimetry (DSC) is ubiquitous in pharmaceutical development, but the related technique of isothermal calorimetry (IC) is complementary and can be used to investigate a range of processes not amenable to analysis by DSC. Typically, IC is used for longer-term stability indicating or excipient compatibility assays because both the temperature and relative humidity (RH) in the sample ampoule can be controlled. However, instrument design and configuration, such as titration, gas perfusion or ampoule-breaking (solution) calorimetry, allow quantification of more specific values, such as binding enthalpies, heats of solution and quantification of amorphous content. As ever, instrument selection, experiment design and sample preparation are critical to ensuring the relevance of any data recorded. This article reviews the use of isothermal, titration, gas-perfusion and solution calorimetry in the context of pharmaceutical development, with a focus on instrument and experimental design factors, highlighted with examples from the recent literature.

  4. A microfabrication-based approach to quantitative isothermal titration calorimetry.

    Science.gov (United States)

    Wang, Bin; Jia, Yuan; Lin, Qiao

    2016-04-15

    Isothermal titration calorimetry (ITC) directly measures heat evolved in a chemical reaction to determine equilibrium binding properties of biomolecular systems. Conventional ITC instruments are expensive, use complicated design and construction, and require long analysis times. Microfabricated calorimetric devices are promising, although they have yet to allow accurate, quantitative ITC measurements of biochemical reactions. This paper presents a microfabrication-based approach to integrated, quantitative ITC characterization of biomolecular interactions. The approach integrates microfabricated differential calorimetric sensors with microfluidic titration. Biomolecules and reagents are introduced at each of a series of molar ratios, mixed, and allowed to react. The reaction thermal power is differentially measured, and used to determine the thermodynamic profile of the biomolecular interactions. Implemented in a microdevice featuring thermally isolated, well-defined reaction volumes with minimized fluid evaporation as well as highly sensitive thermoelectric sensing, the approach enables accurate and quantitative ITC measurements of protein-ligand interactions under different isothermal conditions. Using the approach, we demonstrate ITC characterization of the binding of 18-Crown-6 with barium chloride, and the binding of ribonuclease A with cytidine 2'-monophosphate within reaction volumes of approximately 0.7 µL and at concentrations down to 2mM. For each binding system, the ITC measurements were completed with considerably reduced analysis times and material consumption, and yielded a complete thermodynamic profile of the molecular interaction in agreement with published data. This demonstrates the potential usefulness of our approach for biomolecular characterization in biomedical applications.

  5. Isothermal Kinetics of Catalyzed Air Oxidation of Diesel Soot

    Directory of Open Access Journals (Sweden)

    R. Prasad

    2011-01-01

    Full Text Available To comply with the stringent emission regulations on soot, diesel vehicles manufacturers more and more commonly use diesel particulate filters (DPF. These systems need to be regenerated periodically by burning soot that has been accumulated during the loading of the DPF. Design of the DPF requires rate of soot oxidation. This paper describes the kinetics of catalytic oxidation of diesel soot with air under isothermal conditions. Kinetics data were collected in a specially designed mini-semi-batch reactor. Under the high air flow rate assuming pseudo first order reaction the activation energy of soot oxidation was found to be, Ea = 160 kJ/ mol. ©2010 BCREC UNDIP. All rights reserved(Received: 14th June 2010, Revised: 18th July 2010, Accepted: 9th August 2010[How to Cite: R. Prasad, V.R. Bella. (2010. Isothermal Kinetics of Catalyzed Air Oxidation of Diesel Soot. Bulletin of Chemical Reaction Engineering and Catalysis, 5(2: 95-101. doi:10.9767/bcrec.5.2.796.95-101][DOI:http://dx.doi.org/10.9767/bcrec.5.2.796.95-101 || or local:  http://ejournal.undip.ac.id/index.php/bcrec/article/view/796]Cited by in: ACS 1 |

  6. Loop-mediated isothermal amplification of single pollen grains

    Institute of Scientific and Technical Information of China (English)

    Ali Bektaş; Ignacio Chapela

    2014-01-01

    The polymerase chain reaction (PCR) has been a reliable and fruitful method for many applications in ecology. Nevertheless, unavoidable technical and instrumental require-ments of PCR have limited its widespread application in field situations. The recent development of isothermal DNA amplifica-tion methods provides an alternative to PCR, which circumvents key limitations of PCR for direct amplification in the field. Being able to analyze DNA in the pol en cloud of an ecosystem would provide very useful ecological information, yet would require a field-enabled, high-throughput method for this potential to be realized. Here, we demonstrate the applicability of the loop-mediated DNA amplification method (LAMP), an isothermal DNA amplification technique, to be used in pol en analysis. We demonstrate that LAMP can provide a reliable method to identify species from the pol en cloud, and that it can amplify successful y with sensitivity down to single pol en grains, thus opening the possibility of field-based, high-throughput analysis.

  7. Software Engineering Challenges of Migration Projects

    OpenAIRE

    Geetha, S.; Dr.Alagaramy

    2012-01-01

    Organisations often face the challenges of migration from legacy systems to new target systems. Such migration efforts represent a complex engineering problem. This paper describes migration planning, identifies influencing factors, outlines a set of migration planning activities and offers a set of guidelines for the migration planning

  8. Data Migration for Ontology Evolution

    Institute of Scientific and Technical Information of China (English)

    赵彦; 张雷; 林晨曦; 张卓; 俞勇

    2004-01-01

    Ontology is the conceptual backbone that provides meaning to data on the semantic web. However, ontology is not a static resource and may evolve over time, which often leaves the meaning of data in an undefined or inconsistent state. It is thus very important to have a method to preserve the data and its meaning when ontology changes. This paper proposed a general method that solves the problem using data migration. It analyzed some of the issues in the method including separation of ontology and data, migration specification, migration result and migration algorithm. The paper also instantiates the general mothod in RDF(S) as an example. The RDF(S) example itself is a simple but complete method for migrating RDF data when RDFS ontology changes.

  9. Nonequilibrium steady state of biochemical cycle kinetics under non-isothermal conditions

    CERN Document Server

    Jin, Xiao

    2016-01-01

    Nonequilibrium steady state of isothermal biochemical cycle kinetics has been extensively studied, but much less investigated under non-isothermal conditions. However, once the heat exchange between subsystems is rather slow, the isothermal assumption of the whole system meets great challenge, which is indeed the case inside many kinds of living organisms. Here we generalize the nonequilibrium steady-state theory of isothermal biochemical cycle kinetics, in the master-equation models, to the situation in which the temperatures of subsystems can be far from uniform. We first obtain a new thermodynamic relation between the chemical reaction rates and thermodynamic potentials under such a non-isothermal circumstances, which immediately implies simply applying the isothermal transition-state rate formula for each chemical reaction in terms of only the reactants' temperature, is not thermodynamically consistent. Therefore, we mathematically derive several revised reaction-rate formulas which not only obey the new ...

  10. On the Helmholtz Potential metric: The Isotherm Length-Work Theorem

    OpenAIRE

    Santoro, Manuel

    2004-01-01

    In this paper we introduce the Isotherm Length-Work theorem using the Helmholtz potential metric and the virial expansion of pressure in inverse power of molar volume. The theorem tells us what length of a thermodynamical system described by equation of state through virial expansion along isotherms actually is with such a metric. We also give explicit solutions for thermodynamic length along isotherms in the case of first, second and third order expansion.

  11. The World Economy and Contemporary Migration.

    Science.gov (United States)

    Chaney, Elsa M.

    1979-01-01

    This article discusses international migration as an economic and political concern, comments on recent literature dealing with social aspects of migration, and introduces the articles which follow in this special journal issue dedicated to Caribbean migration to New York. (MC)

  12. The Dynamics of Health and Return Migration

    OpenAIRE

    2011-01-01

    In the final article in a six-part PLoS Medicine; series on Migration & Health, Anita Davies and colleagues from the International Organization for Migration (IOM) discuss the specific health risks and policy needs associated with return migration

  13. Psychosocial Aspects of Migration

    Directory of Open Access Journals (Sweden)

    Ayla Tuzcu

    2014-02-01

    Full Text Available The incident of migration that occurs as a result of the mobility of individuals between various regions and is considered a social change process brings along various factors. Among these factors, the most important one is the culture of the new society where the immigrant begins to live and the process of adaptation with this culture. Individuals from different cultures are required to live together, cope with differences and overcome the difficulties. The process of adaptation to the new lifestyle might cause the individual to have some feelings such as loneliness, socially isolation, being alienated, being regretful and self-depreciation, and consequently experience a greater stress. Being unable to cope with stress efficiently creates risks in individuals in terms of health problems such as anxiety and depression. Healthcare professionals are required to evaluate life styles, difficulties and coping levels of immigrants in order to protect and develop their mental health. [Psikiyatride Guncel Yaklasimlar - Current Approaches in Psychiatry 2014; 6(1.000: 56-66

  14. Basic neutronics. Neutrons migration

    International Nuclear Information System (INIS)

    This article presents the basic neutronics necessary for the understanding of the operation of the different types of nuclear reactors: 1 - introduction to neutronics: principle of fission chain reactions, fast neutron reactors and thermal neutron reactors, capture, neutron status, variations with the reactor lattices; 2 - Boltzmann equation: neutrons population, neutrons migration, characterization of neutrons population and reactions, integral form of the Boltzmann equation, integral-differential form, equivalence between the two forms; 3 - reactor kinetics: fast neutrons and delayed neutrons, kinetic equations in punctual model, Nordheim equation, reactivity jumps, reactivity ramp; 4 - diffusion equation: local neutron status, Fick's law, diffusion equation, initial, boundary and interface conditions, nuclei in infinite and homogenous medium, some examples of solutions, developments in Eigenmodes; 5 - one-group theory: equation of the 'one-group - diffusion' theory, critical condition of the naked and homogenous reactor, critical condition of a reactor with reflectors, generalizations; 6 - neutrons moderation: different moderation mechanisms, elastic shock laws, moderation equation, some examples of solutions; 7 - resonance absorption of neutrons: advantage of the discontinuous moderation character, advantage of an heterogenous disposition, classical formula of the anti-trap factor in homogenous and heterogenous situation; 8 - neutrons thermalization: notions of thermalization mechanisms, thermalization equation, Maxwell spectrum, real spectrum, classical formula of the thermal utilisation factor, classical formula of the reproduction factor, moderation optimum. (J.S.)

  15. Musei del migration heritage

    Directory of Open Access Journals (Sweden)

    Patrizia Dragoni

    2015-01-01

    Since the second half of the 1960s of the 20th century, a profound cultural innovation was accompanied to the radical change in the social, political and economic climate. The anthropological notion of culture as opposed to idealistic vision, the unusual and strong interest in material culture, the enunciation of the concept of cultural property by the Franceschini Commission, the luck of the Public History bring a change of the disciplinary statutes of historical sciences, which begin to attend to social history, focusing on the spontaneous sources of information and initiating experiences of oral history. To all this a remarkable transformation of the themes and of the social function of museums is added. This paper illustrates, in relation to this more general context, the foundation and the dissemination of museums dedicated to the history of migration in Italy and in the world, enunciates their possible social utility for the integration of present migrants in Italy and illustrates, by way of example, the museum recently opened in Recanati.

  16. Neuritin 1 promotes neuronal migration.

    Science.gov (United States)

    Zito, Arianna; Cartelli, Daniele; Cappelletti, Graziella; Cariboni, Anna; Andrews, William; Parnavelas, John; Poletti, Angelo; Galbiati, Mariarita

    2014-01-01

    Neuritin 1 (Nrn1 or cpg15-1) is an activity-dependent protein involved in synaptic plasticity during brain development, a process that relies upon neuronal migration. By analyzing Nrn1 expression, we found that it is highly expressed in a mouse model of migrating immortalized neurons (GN11 cells), but not in a mouse model of non-migrating neurons (GT1-7 cells). We thus hypothesized that Nrn1 might control neuronal migration. By using complementary assays, as Boyden's microchemotaxis, scratch-wounding and live cell imaging, we found that GN11 cell migration is enhanced when Nrn1 is overexpressed and decreased when Nrn1 is silenced. The effects of Nrn1 in promoting neuronal migration have been then confirmed ex vivo, on rat cortical interneurons, by Boyden chamber assays and focal electroporation of acute embryonic brain slices. Furthermore, we found that Nrn1 level modulation affects GN11 cell morphology. The process is also paralleled by Nrn1-induced α-tubulin post-translational modifications, a well-recognized marker of microtubule stability. Altogether, the data demonstrate a novel function of Nrn1 in promoting migration of neuronal cells and indicate that Nrn1 levels impact on microtubule stability. PMID:23212301

  17. A modified Langmuir-Freundlich isotherm model for simulating pH-dependent adsorption effects

    Science.gov (United States)

    Jeppu, Gautham P.; Clement, T. Prabhakar

    2012-03-01

    Analytical isotherm equations such as Langmuir and Freundlich isotherms are widely used for modeling adsorption data. However, these isotherms are primarily useful for simulating data collected at a fixed pH value and cannot be easily adapted to simulate pH-dependent adsorption effects. Therefore, most adsorption studies currently use numerical surface-complexation models (SCMs), which are more complex and time consuming than traditional analytical isotherm models. In this work, we propose a new analytical isotherm model, identified as the modified Langmuir-Freundlich (MLF) isotherm, which can be used to simulate pH-dependent adsorption. The MLF isotherm uses a linear correlation between pH and affinity coefficient values. We validated the proposed MLF isotherm by predicting arsenic adsorption onto two different types of sorbents: pure goethite and goethite-coated sand. The MLF model gave good predictions for both experimental and surface complexation-model predicted datasets for these two sorbents. The proposed analytical isotherm framework can help reduce modeling complexity, model development time, and computational efforts. One of the limitations of the proposed method is that it is currently valid only for single-component systems. Furthermore, the model requires a system-specific pH. vs. affinity coefficient relation. Despite these limitations, the approach provides a promising analytical framework for simulating pH-dependent adsorption effects.

  18. Tracing sediment sources in the Williams River catchment using caesium-137 and heavy metals: towards an assessment of the relative importance of surface erosion and gully erosion

    International Nuclear Information System (INIS)

    Recent sediment sourcing in the 1175km2 Williams River catchment near Newcastle, NSW, has involved the use of caesium-137 (137Cs) and heavy metals to identify zones of erosion and estimate erosion rates. Sediment sources to the Williams River include sheet erosion from forested and grazed lands, stream channels (especially banks), gullies and roads. The fallout environmental radioisotope 137Cs was used to assess the erosion status of five vegetated slopes using soil sampling along transects. The net loss or gain of 137Cs at each sampling point was compared with the 137Cs level at a reference site at the slope crest. Net soil loss at each point was calculated from an Australian regression model relating net soil loss from runoff-erosion plots to 137Cs deficit in soils (n=34; r=0.84). Net soil gain was calculated using the regression model in reverse mode. A weighted net soil loss (or gain) was then calculated for each slope transect. Results showed low net soil loss, ranging from zero to 0.64 t ha-1 yr1, suggesting that slopes were not major contributors of sediment to the Williams River. A small sub-catchment south of Wirragulla Hill, typical of the lower Williams region, was selected for more detailed tracing of sediment sources. The catchment contains gullies, sheet-erosion exposed sub-soil, grassland and one unsealed road. Heavy metals and 137Cs have been used to fingerprint the sources, and these measurements will be compared with suspended sediment collected from drainage water in the creek. Only preliminary results have been obtained for this component of the study. The paper will assess these two approaches for the identification of sediment sources and discuss practical applications in water resources management

  19. Migration and the Wage Curve:

    DEFF Research Database (Denmark)

    Brücker, Herbert; Jahn, Elke J.

      Based on a wage curve approach we examine the labor market effects of migration in Germany. The wage curve relies on the assumption that wages respond to a change in the unemployment rate, albeit imperfectly. This allows one to derive the wage and employment effects of migration simultaneously in...... with a vocational degree. The wage and employment effects of migration are moderate: a 1 percent increase in the German labor force through immigration increases the aggregate unemployment rate by less than 0.1 percentage points and reduces average wages by less 0.1 percent. While native workers...

  20. Migration aspirations in Ukraine: Human rights violations as migration drivers

    OpenAIRE

    Borshchevska, Yuliya

    2014-01-01

    Ukraine is ranked highly among emigration countries and in particular among countries supplying labor migrants to the EU and Russia. The slumping economy and deteriorating political situation with an increasing number of authoritarian traits logically evoke the question of how non-economic motivation factors impact migration aspirations in Ukraine. The worsening human rights situation in the country is, in a way, seen as a separate matter and is not always associated with migration. This arti...

  1. Moisture ingress into electronics enclosures under isothermal conditions

    DEFF Research Database (Denmark)

    Staliulionis, Zygimantas; Jabbaribehnam, Mirmasoud; Hattel, Jesper Henri

    2016-01-01

    The number of electronics used in outdoor environment is constantly growing. The humidity causes about 19 % of all electronics failures and, especially, moisture increases these problems due to the ongoing process of miniaturization and lower power consumption of electronic components. Moisture...... loads are still not understood well by design engineers, therefore this field has become one of the bottlenecks in the electronics system design. The objective of this paper is to model moisture ingress into an electronics enclosure under isothermal conditions. The moisture diffusion model is based...... on a 1D quasi-steady state (QSS) approximation for Fick's second law. This QSS approach is also described with an electrical analogy which gives a fast tool in modelling of the moisture response. The same QSS method is applied to ambient water vapour variations. The obtained results are compared...

  2. Isothermal corrosion Fe3Si alloy in liquid zinc

    Institute of Scientific and Technical Information of China (English)

    Wen jun Wang; Junping Lin; Yanli Wang; Guoliang Chen

    2007-01-01

    The isothermal corrosion testing,microscopic examination and the performance of Fe3Si alloy as materials of construction for bath hardware in continuous hot-dipping lines were studied.The corrosion of Fe3Si alloy in molten zinc was controlled by attacking the grain boundaries preferentially.Aluminum reacted with iron of Fe3Si alloy firstly while the samples were immersed in molten zinc,although aluminum contents in the molten zinc were very low.The phase of reaction product was thought to be Fe2Al5.The corrosion rate of the Fe3Si alloy in molten zinc was determined to be approximately 2.9×10-3 mm/h,therefore the liquid zinc corrosion resistance of Fe3Si alloy was very weak.

  3. Phosphorus isothermal adsorption characteristics of mulch of bioretention

    Directory of Open Access Journals (Sweden)

    Mei Ying

    2012-01-01

    Full Text Available This study aims to identify mulch of bioretention which has high phosphorus sorption capacity. The phosphorus adsorption characteristics of five types of mulch of bioretention are studied by three isothermal adsorption experiments. Results show that the Langmuir eqution is suitable for describing absorption characteristics of five types of mulch. The positive values of Gibbs free energy for phosphorus indicate that the phosphorus biosorption by five mulches is a non-spontaneous process, and the values of mean sorption free energy of mulch are less than 8 kJ/mol, which proves that the adsorption process can be dominated by physical forces. The vermiculite is the better mulch of bioretention based on high phosphorus removal capacity.

  4. Isothermal DNA amplification strategies for duplex microorganism detection.

    Science.gov (United States)

    Santiago-Felipe, Sara; Tortajada-Genaro, Luis Antonio; Morais, Sergi; Puchades, Rosa; Maquieira, Ángel

    2015-05-01

    A valid solution for micro-analytical systems is the selection of a compatible amplification reaction with a simple, highly-integrated efficient design that allows the detection of multiple genomic targets. Two approaches under isothermal conditions are presented: recombinase polymerase amplification (RPA) and multiple displacement amplification (MDA). Both methods were applied to a duplex assay specific for Salmonella spp. and Cronobacter spp., with excellent amplification yields (0.2-8.6 · 10(8) fold). The proposed approaches were successfully compared to conventional PCR and tested for the milk sample analysis as a microarray format on a compact disc (support and driver). Satisfactory results were obtained in terms of resistance to inhibition, selectivity, sensitivity (10(1)-10(2)CFU/mL) and reproducibility (below 12.5%). The methods studied are efficient and cost-effective, with a high potential to automate microorganisms detection by integrated analytical systems working at a constant low temperature.

  5. Adsorption isotherm of uranyl ions by fish scales of corvina

    International Nuclear Information System (INIS)

    Fish scale is by-product of fishery. The scales are mainly formed by hydroxyapatite and collagen forming a kind of natural composite with a large specific surface area that intensifies the adsorption process. In this paper the potential of adsorption of scales of Corvina fish for uranyl ions from nitric solutions was studied. The scales were washed several times with faucet water, sun-dried, triturated and sieved. Equilibrium and kinetic studies in adsorption of uranyl ions in batch systems were carried out at room temperature. Equilibrium time was reached at 5 min for 0.1 g L-1 uranyl solution with removal efficiency over 82%, and at 1 min of contact was observed about 60% of removal. The equilibrium isotherm was obtained and the Langmuir model fitted best. These preliminary results are very promising, showing great perspectives of application of the fish scales as biosorbent for uranyl ions in radioactive wastewater treatment processes with a sustainable technology. (author)

  6. Simulation of non-isothermal transient flow in gas pipeline

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira Junior, Luis Carlos; Soares, Matheus; Lima, Enrique Luis; Pinto, Jose Carlos [Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Quimica; Muniz, Cyro; Pires, Clarissa Cortes; Rochocz, Geraldo [ChemTech, Rio de Janeiro, RJ (Brazil)

    2009-07-01

    Modeling of gas pipeline usually considers that the gas flow is isothermal (or adiabatic) and that pressure changes occur instantaneously (quasi steady state approach). However, these assumptions are not valid in many important transient applications (changes of inlet and outlet flows/pressures, starting and stopping of compressors, changes of controller set points, among others). Besides, the gas properties are likely to depend simultaneously on the pipe position and on the operation time. For this reason, a mathematical model is presented and implemented in this paper in order to describe the gas flow in pipeline when pressure and temperature transients cannot be neglected. The model is used afterwards as a tool for reconciliation of available measured data. (author)

  7. Isothermal titration calorimetry of ion-coupled membrane transporters.

    Science.gov (United States)

    Boudker, Olga; Oh, SeCheol

    2015-04-01

    Binding of ligands, ranging from proteins to ions, to membrane proteins is associated with absorption or release of heat that can be detected by isothermal titration calorimetry (ITC). Such measurements not only provide binding affinities but also afford direct access to thermodynamic parameters of binding--enthalpy, entropy and heat capacity. These parameters can be interpreted in a structural context, allow discrimination between different binding mechanisms and guide drug design. In this review, we introduce advantages and limitations of ITC as a methodology to study molecular interactions of membrane proteins. We further describe case studies where ITC was used to analyze thermodynamic linkage between ions and substrates in ion-coupled transporters. Similar type of linkage analysis will likely be applicable to a wide range of transporters, channels, and receptors.

  8. Applications of isothermal titration calorimetry in protein science

    Institute of Scientific and Technical Information of China (English)

    Yi Liang

    2008-01-01

    During the past decade,isothermal titration calorimetry (ITC)has developed from a specialist method for understanding molecular interactions and other biological processes within cells to a more robust,widely used method.Nowadays,ITC is used to investigate all types of protein interactions,including protein-protein interactions,protein-DNA/RNA interactions,protein-small molecule interactions and enzyme kinetics;it provides a direct route to the complete thermodynamic characterization of protein interactions.This review concentrates on the new applications of ITC in protein folding and misfolding,its traditional application in protein interactions,and an overview of what can be achieved in the field of protein science using this method and what developments are likely to occur in the near future.Also,this review discusses some new developments of ITC method in protein science,such as the reverse titration of ITC and the displacement method of ITC.

  9. Isothermal titration calorimetry of membrane proteins - progress and challenges.

    Science.gov (United States)

    Rajarathnam, Krishna; Rösgen, Jörg

    2014-01-01

    Integral membrane proteins, including G protein-coupled receptors (GPCR) and ion channels, mediate diverse biological functions that are crucial to all aspects of life. The knowledge of the molecular mechanisms, and in particular, the thermodynamic basis of the binding interactions of the extracellular ligands and intracellular effector proteins is essential to understand the workings of these remarkable nanomachines. In this review, we describe how isothermal titration calorimetry (ITC) can be effectively used to gain valuable insights into the thermodynamic signatures (enthalpy, entropy, affinity, and stoichiometry), which would be most useful for drug discovery studies, considering that more than 30% of the current drugs target membrane proteins. This article is part of a Special Issue entitled: Structural and biophysical characterisation of membrane protein-ligand binding.

  10. Moisture ingress into electronics enclosures under isothermal conditions

    Science.gov (United States)

    Staliulionis, Ž.; Jabbari, M.; Hattel, J. H.

    2016-06-01

    The number of electronics used in outdoor environment is constantly growing. The humidity causes about 19 % of all electronics failures and, especially, moisture increases these problems due to the ongoing process of miniaturization and lower power consumption of electronic components. Moisture loads are still not understood well by design engineers, therefore this field has become one of the bottlenecks in the electronics system design. The objective of this paper is to model moisture ingress into an electronics enclosure under isothermal conditions. The moisture diffusion model is based on a 1D quasi-steady state (QSS) approximation for Fick's second law. This QSS approach is also described with an electrical analogy which gives a fast tool in modelling of the moisture response. The same QSS method is applied to ambient water vapour variations. The obtained results are compared to an analytical solution and very good agreement is found.

  11. Study on Non- Isothermal Decomposition Kinetics of Ephedrini Hydrochloridum

    Institute of Scientific and Technical Information of China (English)

    Tang Wan-jun; Chen Dong-hua; Sheng Yu-fang

    2003-01-01

    The thermal decomposition processes of ephed-rini hydrochloridum and its kinetics are studied by TG-DTG techniques. A combined method, which includes Achar meth-od, Coats-Redfern method, and Ozawa method, is put for-ward for determining kinetic model under non-isothermal con-ditions. By applying the combined method, it is determined that the thermal decomposition of ephedrini hydrochloridum is subjected to cylindrical symmetric diffusion. And the reaction function is f(α) = 2(1 - α)1/2, apparent activation energy(115. 26±3.55) kJ @ mol-1 , pre-exponential factor 4. 62 ×108 s-1. Results show that the combined method is feasible and simple.

  12. Isothermal Crystallization Kinetics of Palm Oil with Additives

    Directory of Open Access Journals (Sweden)

    N. Su

    2015-04-01

    Full Text Available This study investigates the isothermal crystallization kinetics of palm oil with additives by Differential Scanning Calorimetry (DSC. The induction time of nucleation and crystallization are obtained by simulating the crystal process using the Gompertz model. The equilibrium melting temperature is obtained via the Hoffman-Weeks methods. The Gibbs free energy of nucleation was calculated by using the Fisher-Turnbull equation and the equilibrium melting temperature. The results indicate that the span 85 has an inhibition effect on nucleation and crystallization kinetics of palm oil. The span 85 can raise the equilibrium melting temperature of palm oil. The span 85 can obviously delay the induction time of nucleation and crystallization at 0.01 and 0.1% level. Although span 85 at 0.05% concentration level also can delay the induction time, it exhibits an effect of promoting nucleation. However, the crystal is uncomplicated in the system containing additives compared to the pure palm oil.

  13. Novel investigation of enzymatic biodiesel reaction by isothermal calorimetry

    DEFF Research Database (Denmark)

    Søtoft, Lene Fjerbaek; Westh, Peter; Christensen, Knud V.;

    2010-01-01

    Isothermal calorimetry (ITC) was used to investigate solvent-free enzymatic biodiesel production. The transesterification of rapeseed oil with methanol and ethanol was catalyzed by immobilized lipase Novozym 435 at 40 °C. The aim of the study was to determine reaction enthalpy for the enzymatic...... transesterification and to elucidate the mass transfer and energetic processes taking place. Based on the measured enthalpy and composition change in the system, the heat of reaction at 40 °C for the two systems was determined as −9.8 ± 0.9 kJ/mole biodiesel formed from rapeseed oil and methanol, and −9.3 ± 0.7 k...

  14. Isothermal equation of state of a lithium fluoride single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Kim, K.Y.

    1975-01-01

    An isothermal equation of state of a LiF single crystal was determined from length change measurements of the specimen as a function of hydrostatic pressure up to approximately 7 kbars at 28 to 41/sup 0/C. The length change was measured with an accuracy of approximately 500 A by using a Fabry Perot type He--Ne laser interferometer for a 1-m long specimen at temperatures constant to less than 0.002/sup 0/C. Several two- and three-parameter equations of state were used in analyzing the measured pressure-volume data. The computer fit for each equation of state determines not only the value of its parameters but also the standard deviations associated with them and one dependent variable, either pressure or volume. With the parameters determined, the equations of state are extrapolated to approximately 5 megabars in order to see discrepancies. Using the Born model of ionic solids, two equations of state were derived both from a power law potential and from an exponential form for the repulsive energy of alkali metal halides and used to fit the pressure-volume data of a LiF single crystal. They are also extrapolated to approximately 5 megabars. The Birch's two-parameter equation and the Grover, Getting, and Kennedy equation are indistinguishable from the two equations of state derived from the Born model for pressures approximately equal to or less than 800 kbars within +-20 kbars. The above four equations of state also fit closely the Pagannone and Drickamer static compression data, the Christian shock wave data, and the Kormer et al. shock wave data. The isothermal bulk modulus and its first pressure derivative at atmospheric pressure and 28.83/sup 0/C are 664.5 +- 0.5 kbars and 5.40 +- 0.18, respectively, in close agreement with those values ultrasonically measured by R. A. Miller and C. S. Smith. (auth)

  15. Precision retrieval of non-isothermal exo-atmospheres

    Science.gov (United States)

    Waldmann, Ingo Peter; Rocchetto, Marco

    2015-12-01

    Spectroscopy of extrasolar planets is as fast moving as it is new. When trying to characterise the atmospheres of these foreign worlds, we are faced with three challenges: 1) The correct treatment of atmospheric opacities at high temperatures, 2) Low signal-to-noise of the observed data, and 3) Large, degenerate parameter spaces. To advance in the interpretation of exoplanetary atmospheres, one must address these challenges in one coherent framework. This is particularly true for emission spectroscopy, where the need for non-isothermal temperature-pressure profiles significantly increases degeneracies in low signal-to-noise data. In the light of these challenges, we developed a novel, bayesian atmospheric retrieval suite, Tau-REx (Waldmann et al. 2015a,b). Tau-REx is a full line-by-line emission/transmission spectroscopy retrieval code based on the most complete hot line-lists from the ExoMol project. For emission spectroscopy, the correct retrieval of the atmosphere’s thermal gradient is extremely challenging with sparse and/or low SNR data. Tau-REx implements a novel two-stage retrieval algorithm which allows the code to iteratively adapt its retrieval complexity to the likelihood surface of the observed data. This way we achieve a very high retrieval accuracy and robustness to low SNR data. Using nested-sampling in conjunction with large scale cluster computing, Tau-REx integrates the full Bayesian Evidence, which allows for precise model selection of the exoplanet’s chemistry and thermal dynamics. Precision and statistical rigour is paramount in the measurement of quantities such as the carbon-oxygen ratio of planets which allow insights into the formation history of these exotic worlds. In this conference I will discuss the intricacies of retrieving the thermal emission of non-isothermal atmospheres and what can be learned from data of current and future facilities.

  16. Liouvillian integrability of gravitating static isothermal fluid spheres

    Energy Technology Data Exchange (ETDEWEB)

    Iacono, Roberto, E-mail: roberto.iacono@enea.it [ENEA-C. R. Casaccia, Via Anguillarese 301, 00123 Roma (Italy); Llibre, Jaume, E-mail: jllibre@mat.uab.cat [Departament de Matemàtiques, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Catalonia (Spain)

    2014-10-01

    We examine the integrability properties of the Einstein field equations for static, spherically symmetric fluid spheres, complemented with an isothermal equation of state, ρ = np. In this case, Einstein's equations can be reduced to a nonlinear, autonomous second order ordinary differential equation (ODE) for m/R (m is the mass inside the radius R) that has been solved analytically only for n = -1 and n = -3, yielding the cosmological solutions by De Sitter and Einstein, respectively, and for n = -5, case for which the solution can be derived from the De Sitter's one using a symmetry of Einstein's equations. The solutions for these three cases are of Liouvillian type, since they can be expressed in terms of elementary functions. Here, we address the question of whether Liouvillian solutions can be obtained for other values of n. To do so, we transform the second order equation into an equivalent autonomous Lotka–Volterra quadratic polynomial differential system in R² and characterize the Liouvillian integrability of this system using Darboux theory. We find that the Lotka–Volterra system possesses Liouvillian first integrals for n = -1, -3, -5, which descend from the existence of invariant algebraic curves of degree one, and for n = -6, a new solvable case, associated to an invariant algebraic curve of higher degree (second). For any other value of n, eventual first integrals of the Lotka–Volterra system, and consequently of the second order ODE for the mass function must be non-Liouvillian. This makes the existence of other solutions of the isothermal fluid sphere problem with a Liouvillian metric quite unlikely.

  17. Liouvillian integrability of gravitating static isothermal fluid spheres

    Science.gov (United States)

    Iacono, Roberto; Llibre, Jaume

    2014-10-01

    We examine the integrability properties of the Einstein field equations for static, spherically symmetric fluid spheres, complemented with an isothermal equation of state, ρ = np. In this case, Einstein's equations can be reduced to a nonlinear, autonomous second order ordinary differential equation (ODE) for m/R (m is the mass inside the radius R) that has been solved analytically only for n = -1 and n = -3, yielding the cosmological solutions by De Sitter and Einstein, respectively, and for n = -5, case for which the solution can be derived from the De Sitter's one using a symmetry of Einstein's equations. The solutions for these three cases are of Liouvillian type, since they can be expressed in terms of elementary functions. Here, we address the question of whether Liouvillian solutions can be obtained for other values of n. To do so, we transform the second order equation into an equivalent autonomous Lotka-Volterra quadratic polynomial differential system in {R}^2, and characterize the Liouvillian integrability of this system using Darboux theory. We find that the Lotka-Volterra system possesses Liouvillian first integrals for n = -1, -3, -5, which descend from the existence of invariant algebraic curves of degree one, and for n = -6, a new solvable case, associated to an invariant algebraic curve of higher degree (second). For any other value of n, eventual first integrals of the Lotka-Volterra system, and consequently of the second order ODE for the mass function must be non-Liouvillian. This makes the existence of other solutions of the isothermal fluid sphere problem with a Liouvillian metric quite unlikely.

  18. A study of the water vapor sorption isotherms of hardened cement pastes: Possible pore structure changes at low relative humidity and the impact of temperature on isotherms

    DEFF Research Database (Denmark)

    Wu, Min; Johannesson, Björn; Geiker, Mette Rica

    2014-01-01

    Using water vapor sorption isotherms measured by the “dynamic vapor sorption” (DVS) method, a resaturation study was conducted to investigate possible pore structure changes of hardened cement paste samples caused by the drying at low relative humidity during desorption measurements. The results...... indicate that either the relatively short term drying does not cause any microstructure changes or the pore structure of the hardened cement paste samples can be restored during the absorption process. Additionally, the temperature dependency of sorption isotherms was investigated using both hardened...... cement paste samples and a model material MCM-41. The pronounced impact of temperature on desorption isotherms of cement based materials as reported in literature was not found in this investigation. The results suggest that the differences between the sorption isotherms measured at different...

  19. Interregional migration flows in Indonesia

    NARCIS (Netherlands)

    Wajdi, N.; van Wissen, L.J.G.; Mulder, C.H.

    2015-01-01

    Population Census and Intercensal Population Survey data permit description of the origin–destination patterns that characterize interregional migration flows in Indonesia. Application of the framework of population redistribution proposed by Long (1985) results in indications of over-urbanization,

  20. Labour market frictions and migration

    NARCIS (Netherlands)

    Cremers, Jan

    2016-01-01

    The 4th contribution to the series INT-AR papers is dedicated to the methods of assessing labour market frictions. The paper provides a (brief) international comparison of the role of labour migration in solving these frictions.

  1. [International migration: backgrounds and developments].

    Science.gov (United States)

    De Beer, J

    1997-03-01

    "Net migration [in the Netherlands] has fluctuated strongly during the past decades. In 1983 net migration (including net administrative corrections) was almost zero. In the early 1990s net migration rose to almost 50 thousand per year. In 1994 net migration dropped sharply to a level of 20 thousand, followed by a further decrease in 1995. In 1996 there was a moderate increase. One cause of the strong decline in immigration in the mid-1990s may be the increasingly strict immigration policy. Another explanation of fluctuations in immigration is the business cycle. A regression analysis for the period 1973-1995 shows that there is a negative relationship between immigration of non-Dutch nationals and the unemployment rate in the Netherlands and a positive relationship between emigration and the unemployment rate." (EXCERPT) PMID:12321085

  2. The migration of university graduates

    DEFF Research Database (Denmark)

    Drejer, Ina; Holm, Jacob Rubæk; Nielsen, Kristian

    Several studies have documented that highly educated citizens contribute to regional economic performance (Moretti, 2013; Faggian and McCann,2009b; Sterlacchini 2008). Moreover, Åstebro et al. (2012) emphasize the importance of promoting start-up by recent university graduates. Thus, the retention...... in university as well as migration after graduation using the terminology of Faggian and McCann (2009a). Graduates’ migration is mainly studied in relation to first employment. The analysis also includes the migration of university graduates who become entrepreneurs. The different migration patterns...... are combined with measures of performance for wage-earners, expressed as level and growth rate of hourly wages, and for entrepreneurs, expressed as firm survival and growth in sales and employees....

  3. Homeward bound: Yemeni return migration.

    Science.gov (United States)

    Colton, N A

    1993-01-01

    The author discusses the return migration of Yemenis from Saudi Arabia during the period 1970-1989. "Through the use of original, empirical data collected in Yemen, this article sheds light on who these returning migrants are, where they have come from, and what sort of future awaits them.... The survey conducted on return migration was administered in the winter and spring of 1989 in a region of North Yemen called al-Hujariyya."

  4. Tackling the European Migration Problems

    OpenAIRE

    Zimmermann, Klaus F.

    1995-01-01

    A fortress Europe immigration policy is currently observed throughout the European Union. The European migration problem seems to be that, in the face of high and persistent unemployment rates, additional immigration implies further unemployment. This might not be true if immigration helps to erode institutional constraints and enhances labor market flexibility, a point that is seen of particular virtue in the European setting. The paper also argues that past European migration, although limi...

  5. Migrations, public goods and taxes

    OpenAIRE

    Jaskold Gabszewicz, Jean; Gvetadze, Salome; Zanaj, Skerdilajda

    2011-01-01

    This paper examines how and why people migrate between two re- gions with asymmetric size. The agglomeration force comes from the scale economies in the provision of local public goods, whereas the disper- sion force comes from congestion in consumption of public goods. Public goods considered resemble club goods (or public goods with congestion) and people are heterogeneous in their migration costs. We find that the large countries can be destination of migrants for sufficiently high provisi...

  6. Simple rules guide dragonfly migration

    OpenAIRE

    Wikelski, Martin; Moskowitz, David; Adelman, James S.; Cochran, Jim; Wilcove, David S; May, Michael L

    2006-01-01

    Every year billions of butterflies, dragonflies, moths and other insects migrate across continents, and considerable progress has been made in understanding population-level migratory phenomena. However, little is known about destinations and strategies of individual insects. We attached miniaturized radio transmitters (ca 300 mg) to the thoraxes of 14 individual dragonflies (common green darners, Anax junius) and followed them during their autumn migration for up to 12 days, using receiver-e...

  7. County Amenities and Net Migration

    OpenAIRE

    Rupasingha, Anil; Goetz, Stephan J.

    2004-01-01

    U.S. county-level net migration data and a general spatial model are used to examine the effects of various amenities on migration decisions. Results suggest that higher county cancer risks and the presence of superfund sites in a county, or a higher ranking on the Environmental Protection Agency's hazard ranking system, reduce the relative attractiveness of a county to prospective migrants, while natural amenities on balance attract migrants, ceteris paribus. The results also reveal spatial ...

  8. SSI, labor supply, and migration

    OpenAIRE

    Neumark, David; Powers, Elizabeth T.

    2005-01-01

    The Supplemental Security Income (SSI) program in the United States creates incentives for potential aged recipients to reduce labor supply prior to becoming eligible, and our past research finds that older men likely to be eligible for SSI at age 65 reduce their labor supply in the years immediately before the age of eligibility. However, given the dramatic supplementation of SSI benefits in some states, a migration response to these benefits cannot be dismissed, and migration that is associ...

  9. Thermal migration of iron implanted in aluminium at high doses

    International Nuclear Information System (INIS)

    The anneal behaviour of the Fe-Al metastable system produced by implantation of Fe+ ions at 30 keV has been reported. The implant concentrations between 18-42 at percent have been chosen, in order to exceed the normal solid solubility of Fe in Al by about three orders of magnitude. Isothermal annealing has been done under vacuum (55 x 10-6 Torr) at 400deg C and 570 deg C. The iron depth profiles have been determined, by Rutherford backscattering of 2 MeV He+ ions. It has been found that 1) as annealing proceeds, all specimens show rapid enhanced diffusion initially (upto about 30 m), followed by a much slower diffusion as iron ions migrate inwards (2) at implant concentrations 23 at percent, double peaks appear in iron depth profiles, followed by rapid migration of diffused iron towards surface and (3) at still higher anneal times, the out-diffused iron moves inward again. This kind of out-diffusion behaviour in a metallic system has not been reported earlier in the literature. Also, the presence of Fe4Al13 has been identified as terminal phase, using x-ray diffraction techniques. (K.B.)

  10. Negative Saturation Approach for Non-Isothermal Compositional Two-Phase Flow Simulations

    NARCIS (Netherlands)

    Salimi, H.; Wolf, K.-H.; Bruining, J.

    2011-01-01

    This article deals with developing a solution approach, called the non-isothermal negative saturation (NegSat) solution approach. The NegSat solution approach solves efficiently any non-isothermal compositional flow problem that involves phase disappearance, phase appearance, and phase transition. T

  11. Prediction of Pure Component Adsorption Equilibria Using an Adsorption Isotherm Equation Based on Vacancy Solution Theory

    DEFF Research Database (Denmark)

    Marcussen, Lis; Aasberg-Petersen, K.; Krøll, Annette Elisabeth

    2000-01-01

    An adsorption isotherm equation for nonideal pure component adsorption based on vacancy solution theory and the Non-Random-Two-Liquid (NRTL) equation is found to be useful for predicting pure component adsorption equilibria at a variety of conditions. The isotherm equation is evaluated successfully...... adsorption systems, spreading pressure and isosteric heat of adsorption are also calculated....

  12. Evaluation of sugar sorption isotherm measurement by frontal analysis under industrial processing conditions

    NARCIS (Netherlands)

    Vente, Johan A.; Bosch, Hans; Haan, de André B.; Bussmann, Paul J.T.

    2005-01-01

    This paper evaluates frontal analysis for routine sugar isotherm measurements at industrial conditions, that is concentrations up to 400 kg/m3 and a temperature of 60 °C. Sugar isotherms for a gel type cation-exchange resin loaded with metal ions were measured in a HPLC set-up equipped with a UV det

  13. A Sixth-Form Teaching Unit on the Langmuir Adsorption Isotherm

    Science.gov (United States)

    Walkley, G. H.

    1973-01-01

    Presents a teaching unit on the Langmuir absorption isotherm suitable for advanced secondary school chemistry classes. Describes the experimental investigation of the isothermal adsorption of sulfur dioxide on charcoal, and discusses the derivation of the Langmuir equation and some applications. (JR)

  14. Revisiting Isotherm Analyses Using R: Comparison of Linear, Non-linear, and Bayesian Techniques

    Science.gov (United States)

    Extensive adsorption isotherm data exist for an array of chemicals of concern on a variety of engineered and natural sorbents. Several isotherm models exist that can accurately describe these data from which the resultant fitting parameters may subsequently be used in numerical ...

  15. Blowup of Smooth Solutions to the Navier-Stokes Equations for Compressible Isothermal Fluids

    CERN Document Server

    Dapeng, Du; Kaijun, Zhang

    2011-01-01

    It is shown that the one-dimensional or two-dimensional radially symmetric isothermal compressible Navier-Stokes system has no non-trivial global smooth solutions if the initial density is compactly supported. This result is a generalization of Xin's work \\cite{Xin98} to the isothermal case.

  16. One New Method of Nucleic Acid Amplification-Loop-mediated Isothermal Amplification of DNA

    Institute of Scientific and Technical Information of China (English)

    Xue-en FANG; Jian LI; Qin CHEN

    2008-01-01

    Loop-mediated isothermal amplification (LAMP) is a novel nucleic acid amplification method, which amplifies DNA with high specificity, sensitivity, rapidity and efficiency under isothermal conditions using a set of four specially designed primers and a Bst DNA polymerase with strand displacement activity. The basic principle, characteristics, development of LAMP and its applications are summarized in this article.

  17. Towards a new understanding of migration timing

    NARCIS (Netherlands)

    Kölzsch, Andrea; Muskens, Gerard; Kruckenberg, Helmut; Glazov, Peter; Weinzierl, Rolf; Nolet, Bart A.; Wikelski, Martin

    2016-01-01

    According to migration theory and several empirical studies, long-distance migrants are more time-limited during spring migration and should therefore migrate faster in spring than in autumn. Competition for the best breeding sites is supposed to be the main driver, but timing of migration is oft

  18. Distance and Intrastate College Student Migration

    Science.gov (United States)

    Alm, James; Winters, John V.

    2009-01-01

    Most studies of student migration focus on "interstate" migration of college students, largely because the aggregate data typically used are limited in geographic specificity to states. However, interstate migration is only a small part of the total student migration. Public institutions generally get most of their students from within their…

  19. Evaluation of theoretical and empirical water vapor sorption isotherm models for soils

    DEFF Research Database (Denmark)

    Arthur, Emmanuel; Tuller, Markus; Moldrup, Per;

    2016-01-01

    .93 for 207 soils, widely varying in texture and organic carbon content. In addition the potential applicability of the models for prediction of sorption isotherms from known clay content was investigated. While in general all investigated models described measured adsorption and desorption isotherms...... and clay content and subsequent model application for prediction of measured isotherms showed promise for the majority of investigated soils. Only for soils with distinct kaolinitic and smectitic clay mineralogy predicted isotherms did not closely match the measurements.......The mathematical characterization of water vapor sorption isotherms of soils is crucial for modeling processes such as volatilization of pesticides and diffusive and convective water vapor transport. Although numerous physically-based and empirical models were previously proposed to describe...

  20. International migration: a global challenge.

    Science.gov (United States)

    Martin, P; Widgren, J

    1996-04-01

    Trends in international migration are presented in this multiregional analysis. Seven of the world's wealthiest countries have about 33% of the world's migrant population, but under 16% of the total world population. Population growth in these countries is substantially affected by the migrant population. The migration challenge is external and internal. The external challenge is to balance the need for foreign labor and the commitment to human rights for those migrants seeking economic opportunity and political freedom. The internal challenge is to assure the social adjustment of immigrants and their children and to integrate them into society as citizens and future leaders. Why people cross national borders and how migration flows are likely to evolve over the next decades are explained. This report also presents some ways that countries can manage migration or reduce the pressures which force people to migrate. It is recommended that receiving nations control immigration by accelerating global economic growth and reducing wars and human rights violations. This report examines the impact of immigration on international trade, aid, and direct intervention policies. Although migration is one of the most important international economic issues, it is not coordinated by an international group. The European experience indicates that it is not easy to secure international cooperation on issues that affect national sovereignty. It is suggested that countries desiring control of their borders should remember that most people never cross national borders to live or work in another country, that 50% of the world's migrants move among developing countries, and that countries can shift from being emigration to immigration countries. The author suggests that sustained reductions in migration pressure are a better alternative than the "quick fixes" that may invite the very much feared mass and unpredictable movements.

  1. Seasonal survival probabilities suggest low migration mortality in migrating bats.

    Directory of Open Access Journals (Sweden)

    Simone Giavi

    Full Text Available Migration is adaptive if survival benefits are larger than costs of residency. Many aspects of bat migration ecology such as migratory costs, stopover site use and fidelity are largely unknown. Since many migrating bats are endangered, such information is urgently needed to promote conservation. We selected the migrating Leisler's bat (Nyctalus leisleri as model species and collected capture-recapture data in southern Switzerland year round during 6 years. We estimated seasonal survival and site fidelity with Cormack-Jolly-Seber models that accounted for the presence of transients fitted with Bayesian methods and assessed differences between sexes and seasons. Activity peaked in autumn and spring, whereas very few individuals were caught during summer. We hypothesize that the study site is a migratory stopover site used during fall and spring migration for most individuals, but there is also evidence for wintering. Additionally, we found strong clues for mating during fall. Summer survival that included two major migratory journeys was identical to winter survival in males and slightly higher in females, suggesting that the migratory journeys did not bear significant costs in terms of survival. Transience probability was in both seasons higher in males than in females. Our results suggest that, similarly to birds, Leisler's bat also use stopover sites during migration with high site fidelity. In contrast to most birds, the stopover site was also used for mating and migratory costs in terms of survival seemed to be low. Transients' analyses highlighted strong individual variation in site use which makes particularly challenging the study and modelling of their populations as well as their conservation.

  2. MIGRATION IN SIKKIM: FACTS OR FRICTIONS

    OpenAIRE

    Gyaltsen Tsh. Bhutia; Srivastava, R.K.

    2014-01-01

    Today's migrations become one of the important issues in the globe. The increasing influx of migration and the illegal migration has become a great challenge to the policy maker for both the sending and destination economy. The impact of migration on both the economy has genuine issue to be discusses, analysis and closely study. Therefore, this study reveal to quantify the migration population in Sikkim, to assess the impact on the socio-economy fabrics and to suggest the reme...

  3. LABOR MIGRATION IN RUSSIA - PROBLEM OR PROSPECT?

    OpenAIRE

    POMOZGOV ANATOLY IVANOVICH; KISIEV ZAUR EDUARDOVICH

    2016-01-01

    The article shows that international labor migration is an important part of the internationalization process of international economic life. So, the migration processes of the population should be carefully monitored and analyzed in order to develop effective state migration policy. Population mass migration became one of the characteristic phenomena of the second part of XX century world society life. Labor power international migration from this time appears to be the important part of int...

  4. Migration and the Option Value of Waiting

    OpenAIRE

    Burda, Michael C.

    1995-01-01

    Migration is an investment: it involves fixed, unrecoverable costs and uncertain future returns. If migration can be postponed, the option value of doing so may have positive value. Migration may not occur for a range of individuals who would otherwise migrate on a net present valur basis. This paper models the migration decision using ideas developed by Pindyck (1991) and Dixit (1992). Th option value of waiting is related to the interest rate, fixed costs, and especially uncertainty governi...

  5. Migration and sustainability - compatible or contradictory?

    DEFF Research Database (Denmark)

    Røpke, Inge

    2006-01-01

    When the migration issue is discussed in a sustainability perspective, two questions are vital: 1) What is the relationship between migration and the global population growth? 2) What is the relationship between migration and consumption growth, and how does migration influence the distribution...... of consumption possibilities both between and within industrialized and developing countries? Based on responses to these questions, it is argued that reasonably managed migration will be compatible with sustainable development....

  6. STAR: a simple TAL effector assembly reaction using isothermal assembly.

    Science.gov (United States)

    Gogolok, Sabine; Garcia-Diaz, Claudia; Pollard, Steven M

    2016-01-01

    Transcription activator-like effectors (TALEs) contain modular programmable DNA binding domains. Fusing TALEs with effector domains creates synthetic transcription factors (TALE-TFs) or nucleases (TALENs), enabling precise gene manipulations. The construction of TALEs remains challenging due to their repetitive sequences. Here we report a simple TALE assembly reaction (STAR) that enables individual laboratories to generate multiple TALEs in a facile manner. STAR uses an isothermal assembly ('Gibson assembly') that is labour- and cost-effective, accessible, rapid and scalable. A small 68-part fragment library is employed, and the specific TALE repeat sequence is generated within ~8 hours. Sequence-verified TALENs or TALE-TF plasmids targeting 17 bp target sequences can be produced within three days, without the need for stepwise intermediate plasmid production. We demonstrate the utility of STAR through production of functional TALE-TFs capable of activating human SOX2 expression. STAR addresses some of the shortcomings of existing Golden Gate or solid-phase assembly protocols and enables routine production of TALE-TFs that will complement emerging CRISPR/Cas9-based reagents across diverse applications in mammalian stem cell and synthetic biology. PMID:27615025

  7. Generalized linear isotherm regularity equation of state applied to metals

    Directory of Open Access Journals (Sweden)

    H. Sun

    2012-03-01

    Full Text Available A three-parameter equation of state (EOS without physically incorrect oscillations is proposed based on the generalized Lennard-Jones (GLJ potential and the approach in developing linear isotherm regularity (LIR EOS of Parsafar and Mason [J. Phys. Chem., 1994, 49, 3049]. The proposed (GLIR EOS can include the LIR EOS therein as a special case. The three-parameter GLIR, Parsafar and Mason (PM [Phys. Rev. B, 1994, 49, 3049], Shanker, Singh and Kushwah (SSK [Physica B, 1997, 229, 419], Parsafar, Spohr and Patey (PSP [J. Phys. Chem. B, 2009, 113, 11980], and reformulated PM and SSK EOSs are applied to 30 metallic solids within wide pressure ranges. It is shown that the PM, PMR and PSP EOSs for most solids, and the SSK and SSKR EOSs for several solids, have physically incorrect turning points, and pressure becomes negative at high enough pressure. The GLIR EOS is capable not only of overcoming the problem existing in other five EOSs where the pressure becomes negative at high pressure, but also gives results superior to other EOSs

  8. STAR: a simple TAL effector assembly reaction using isothermal assembly

    Science.gov (United States)

    Gogolok, Sabine; Garcia-Diaz, Claudia; Pollard, Steven M.

    2016-01-01

    Transcription activator-like effectors (TALEs) contain modular programmable DNA binding domains. Fusing TALEs with effector domains creates synthetic transcription factors (TALE-TFs) or nucleases (TALENs), enabling precise gene manipulations. The construction of TALEs remains challenging due to their repetitive sequences. Here we report a simple TALE assembly reaction (STAR) that enables individual laboratories to generate multiple TALEs in a facile manner. STAR uses an isothermal assembly (‘Gibson assembly’) that is labour- and cost-effective, accessible, rapid and scalable. A small 68-part fragment library is employed, and the specific TALE repeat sequence is generated within ~8 hours. Sequence-verified TALENs or TALE-TF plasmids targeting 17 bp target sequences can be produced within three days, without the need for stepwise intermediate plasmid production. We demonstrate the utility of STAR through production of functional TALE-TFs capable of activating human SOX2 expression. STAR addresses some of the shortcomings of existing Golden Gate or solid-phase assembly protocols and enables routine production of TALE-TFs that will complement emerging CRISPR/Cas9-based reagents across diverse applications in mammalian stem cell and synthetic biology. PMID:27615025

  9. Binding Isotherms and Cooperative Effects for Metal-DNA Complexes

    CERN Document Server

    Gelagutashvili, Eteri

    2008-01-01

    The stoichiometric binding constants of Nickel(II), Cobalt(II), Manganese(II), Silver(I), Zinc(II) ions with DNA, from Spirulina platensis were determined from their binding isotherms by equilibrium dialysis and atomic absorption spectroscopy. It was shown, that the nature of these ions interaction with DNA, from S .platensis is different. For Cobalt(II), Zinc(II) ions were observed cooperative effects and existence of two different types of the binding sites. Nickel(II)_, Silver(I) -DNA complexes shows independent and identical binding sites and Manganese(II)_ negative cooperative interaction. The logarithm of binding constants for Cobalt (II)_, Nickel (II)_, Manganese (II)_, Zinc (II)_, Silver (I) - DNA, from S. platensis in 3 mM Na(I) are 5.11; 5.18; 4.77; 5.05; 5.42; respectively. The linear correlation of logarithm of binding constants (for complexes of metal-DNA from S. platensis) and the covalent index of Pauling are observed.

  10. Diagnosis of brugian filariasis by loop-mediated isothermal amplification.

    Directory of Open Access Journals (Sweden)

    Catherine B Poole

    Full Text Available In this study we developed and evaluated a Brugia Hha I repeat loop-mediated isothermal amplification (LAMP assay for the rapid detection of Brugia genomic DNA. Amplification was detected using turbidity or fluorescence as readouts. Reactions generated a turbidity threshold value or a clear visual positive within 30 minutes using purified genomic DNA equivalent to one microfilaria. Similar results were obtained using DNA isolated from blood samples containing B. malayi microfilariae. Amplification was specific to B. malayi and B. timori, as no turbidity was observed using DNA from the related filarial parasites Wuchereria bancrofti, Onchocerca volvulus or Dirofilaria immitis, or from human or mosquito. Furthermore, the assay was most robust using a new strand-displacing DNA polymerase termed Bst 2.0 compared to wild-type Bst DNA polymerase, large fragment. The results indicate that the Brugia Hha I repeat LAMP assay is rapid, sensitive and Brugia-specific with the potential to be developed further as a field tool for diagnosis and mapping of brugian filariasis.

  11. Diagnosis of brugian filariasis by loop-mediated isothermal amplification.

    Science.gov (United States)

    Poole, Catherine B; Tanner, Nathan A; Zhang, Yinhua; Evans, Thomas C; Carlow, Clotilde K S

    2012-01-01

    In this study we developed and evaluated a Brugia Hha I repeat loop-mediated isothermal amplification (LAMP) assay for the rapid detection of Brugia genomic DNA. Amplification was detected using turbidity or fluorescence as readouts. Reactions generated a turbidity threshold value or a clear visual positive within 30 minutes using purified genomic DNA equivalent to one microfilaria. Similar results were obtained using DNA isolated from blood samples containing B. malayi microfilariae. Amplification was specific to B. malayi and B. timori, as no turbidity was observed using DNA from the related filarial parasites Wuchereria bancrofti, Onchocerca volvulus or Dirofilaria immitis, or from human or mosquito. Furthermore, the assay was most robust using a new strand-displacing DNA polymerase termed Bst 2.0 compared to wild-type Bst DNA polymerase, large fragment. The results indicate that the Brugia Hha I repeat LAMP assay is rapid, sensitive and Brugia-specific with the potential to be developed further as a field tool for diagnosis and mapping of brugian filariasis.

  12. Characterization of membrane protein interactions by isothermal titration calorimetry.

    Science.gov (United States)

    Situ, Alan J; Schmidt, Thomas; Mazumder, Parichita; Ulmer, Tobias S

    2014-10-23

    Understanding the structure, folding, and interaction of membrane proteins requires experimental tools to quantify the association of transmembrane (TM) helices. Here, we introduce isothermal titration calorimetry (ITC) to measure integrin αIIbβ3 TM complex affinity, to study the consequences of helix-helix preorientation in lipid bilayers, and to examine protein-induced lipid reorganization. Phospholipid bicelles served as membrane mimics. The association of αIIbβ3 proceeded with a free energy change of -4.61±0.04kcal/mol at bicelle conditions where the sampling of random helix-helix orientations leads to complex formation. At bicelle conditions that approach a true bilayer structure in effect, an entropy saving of >1kcal/mol was obtained from helix-helix preorientation. The magnitudes of enthalpy and entropy changes increased distinctly with bicelle dimensions, indicating long-range changes in bicelle lipid properties upon αIIbβ3 TM association. NMR spectroscopy confirmed ITC affinity measurements and revealed αIIbβ3 association and dissociation rates of 4500±100s(-1) and 2.1±0.1s(-1), respectively. Thus, ITC is able to provide comprehensive insight into the interaction of membrane proteins.

  13. Enzyme kinetics determined by single-injection isothermal titration calorimetry.

    Science.gov (United States)

    Transtrum, Mark K; Hansen, Lee D; Quinn, Colette

    2015-04-01

    The purposes of this paper are (a) to examine the effect of calorimeter time constant (τ) on heat rate data from a single enzyme injection into substrate in an isothermal titration calorimeter (ITC), (b) to provide information that can be used to predict the optimum experimental conditions for determining the rate constant (k2), Michaelis constant (KM), and enthalpy change of the reaction (ΔRH), and (c) to describe methods for evaluating these parameters. We find that KM, k2 and ΔRH can be accurately estimated without correcting for the calorimeter time constant, τ, if (k2E/KM), where E is the total active enzyme concentration, is between 0.1/τ and 1/τ and the reaction goes to at least 99% completion. If experimental conditions are outside this domain and no correction is made for τ, errors in the inferred parameters quickly become unreasonable. A method for fitting single-injection data to the Michaelis-Menten or Briggs-Haldane model to simultaneously evaluate KM, k2, ΔRH, and τ is described and validated with experimental data. All four of these parameters can be accurately inferred provided the reaction time constant (k2E/KM) is larger than 1/τ and the data include enzyme saturated conditions.

  14. Measuring the Kinetics of Molecular Association by Isothermal Titration Calorimetry.

    Science.gov (United States)

    Vander Meulen, Kirk A; Horowitz, Scott; Trievel, Raymond C; Butcher, Samuel E

    2016-01-01

    The real-time power response inherent in an isothermal titration calorimetry (ITC) experiment provides an opportunity to directly analyze association kinetics, which, together with the conventional measurement of thermodynamic quantities, can provide an incredibly rich description of molecular binding in a single experiment. Here, we detail our application of this method, in which interactions occurring with relaxation times ranging from slightly below the instrument response time constant (12.5 s in this case) to as large as 600 s can be fully detailed in terms of both the thermodynamics and kinetics. In a binding titration scenario, in the most general case an injection can reveal an association rate constant (kon). Under more restrictive conditions, the instrument time constant-corrected power decay following each injection is simply an exponential decay described by a composite rate constant (kobs), from which both kon and the dissociation rate constant (koff) can be extracted. The data also support the viability of this exponential approach, for kon only, for a slightly larger set of conditions. Using a bimolecular RNA folding model and a protein-ligand interaction, we demonstrate and have internally validated this approach to experiment design, data processing, and error analysis. An updated guide to thermodynamic and kinetic regimes accessible by ITC is provided.

  15. Measuring Multivalent Binding Interactions by Isothermal Titration Calorimetry.

    Science.gov (United States)

    Dam, Tarun K; Talaga, Melanie L; Fan, Ni; Brewer, Curtis F

    2016-01-01

    Multivalent glycoconjugate-protein interactions are central to many important biological processes. Isothermal titration calorimetry (ITC) can potentially reveal the molecular and thermodynamic basis of such interactions. However, calorimetric investigation of multivalency is challenging. Binding of multivalent glycoconjugates to proteins (lectins) often leads to a stoichiometry-dependent precipitation process due to noncovalent cross-linking between the reactants. Precipitation during ITC titration severely affects the quality of the baseline as well as the signals. Hence, the resulting thermodynamic data are not dependable. We have made some modifications to address this problem and successfully studied multivalent glycoconjugate binding to lectins. We have also modified the Hill plot equation to analyze high quality ITC raw data obtained from multivalent binding. As described in this chapter, ITC-driven thermodynamic parameters and Hill plot analysis of ITC raw data can provide valuable information about the molecular mechanism of multivalent lectin-glycoconjugate interactions. The methods described herein revealed (i) the importance of functional valence of multivalent glycoconjugates, (ii) that favorable entropic effects contribute to the enhanced affinities associated with multivalent binding, (iii) that with the progression of lectin binding, the microscopic affinities of the glycan epitopes of a multivalent glycoconjugate decrease (negative cooperativity), (iv) that lectin binding to multivalent glycoconjugates, especially to mucins, involves internal diffusion jumps, (bind and jump) and (v) that scaffolds of glycoconjugates influence their entropy of binding.

  16. Immobilization of Acetobacter aceti on cellulose ion exchangers: adsorption isotherms

    Energy Technology Data Exchange (ETDEWEB)

    Bar, R.; Gainer, J.L.; Kirwan, D.J.

    1986-08-01

    The adsorptive behavior of cells of Acetobacter aceti, ATCC 23746, on DEAE-, TEAE-, and DEHPAE-cellulose ion exchangers in a modified Hoyer's medium at 30 degrees Centigrade was investigated. The maximum observed adsorption capacities varied from 46 to 64 mg dry wt/g resin. The Langmuir isotherm form was used to fit the data, since the cells formed a monolayer on the resin and exhibited saturation. The equilibrium constant in the Langmuir expression was qualitatively correlated with the surface charge density of the resin. The adsorption was also ''normalized'' by considering the ionic capacities of the resins. The exceptionally high normalized adsorption capacity of ECTEOLA-cellulose, 261 mg dry/meq, may be explained by an interaction between the cell wall and the polyglyceryl chains of the exchanging groups in addition to the electrostatic effects. The effect of pH on the bacterial adsorption capacity of ECTEOLA-, TEAE-, and phosphate-cellulose resins was studied and the pH of the bacteria was estimated to be 3.0. 17 references.

  17. Novel investigation of enzymatic biodiesel reaction by isothermal calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Sotoft, Lene Fjerbaek, E-mail: lfj@kbm.sdu.dk [Institute of Chemical Engineering, Biotechnology and Environmental Technology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M (Denmark); Westh, Peter [Department of Life Science and Chemistry, Roskilde University, PO Box 260, DK-4000 Roskilde (Denmark); Christensen, Knud V.; Norddahl, Birgir [Institute of Chemical Engineering, Biotechnology and Environmental Technology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M (Denmark)

    2010-03-30

    Isothermal calorimetry (ITC) was used to investigate solvent-free enzymatic biodiesel production. The transesterification of rapeseed oil with methanol and ethanol was catalyzed by immobilized lipase Novozym 435 at 40 {sup o}C. The aim of the study was to determine reaction enthalpy for the enzymatic transesterification and to elucidate the mass transfer and energetic processes taking place. Based on the measured enthalpy and composition change in the system, the heat of reaction at 40 {sup o}C for the two systems was determined as -9.8 {+-} 0.9 kJ/mole biodiesel formed from rapeseed oil and methanol, and -9.3 {+-} 0.7 kJ/mole when rapeseed oil and ethanol was used. Simple Michaelis-Menten kinetics was not an appropriate choice for describing the kinetics of this heterogeneous system. The experiments demonstrated the possibility of investigating complex reaction mixtures using ITC. Although it is possible to determine thermodynamic properties such as reaction enthalpy and reaction rate, the difficulty in actually measuring the true non-mass-transfer-limited reaction kinetics is exposed by the high time resolution of ITC.

  18. Formation of prestellar cores via non-isothermal gas fragmentation

    CERN Document Server

    Anathpindika, S

    2015-01-01

    Sheet-like clouds are common in turbulent gas and perhaps form via collisions between turbulent gas flows. Having examined the evolution of an isothermal shocked slab in an earlier contribution, in this work we follow the evolution of a sheet-like cloud confined by (thermal)pressure and gas in it is allowed to cool. The extant purpose of this endeavour is to study the early phases of core-formation. The observed evolution of this cloud supports the conjecture that molecular clouds themselves are three-phase media (comprising viz. a stable cold and warm medium, and a third thermally unstable medium), though it appears, clouds may evolve in this manner irrespective of whether they are gravitationally bound. We report, this sheet fragments initially due to the growth of the thermal instability and some fragments are elongated, filament-like. Subsequently, relatively large fragments become gravitationally unstable and sub-fragment into smaller cores. The formation of cores appears to be a three stage process : fi...

  19. Non-Isothermal Crystallization of PET/PLA Blends

    Science.gov (United States)

    Chen, Huipeng; Pyda, Marek; Cebe, Peggy

    2011-03-01

    Binary blends of poly(ethylene terephthalate) with poly(lactic acid), PET/PLA, were studied by differential scanning calorimetry. The solution cast blends were miscible in the melt over the entire composition range. We report the non-isothermal crystallization of: a.) PET, with and without presence of PLA crystals, and b.) PLA, with and without presence of PET crystals. PET can crystallize in all blends, regardless of whether PLA is amorphous or crystalline, and crystallinity of PET decreases as PLA content increases. PLA crystallization is strongly affected by the mobility of the PET. When PET is wholly amorphous, PLA can crystallize weakly even in 70/30 blends. When PET is crystalline, PLA cannot crystallize when its own content is below 0.90. The different behaviors may be related to the tendency of each polymer to form constrained chains, i.e., to form rigid amorphous fraction, RAF. PET is capable of forming a large amount of RAF, whereas relatively smaller amount of RAF forms in PLA. Like the crystals, rigid amorphous fraction of one component may inhibit growth of crystals of the other blend partner. Supported by the National Science Foundation, Polymers Program of the Division of Materials Research under DMR-0602473 and the MRI Program under DMR-0520655.

  20. Non-isothermal crystallization of PET/PLA blends

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Huipeng [Department of Physics and Astronomy, Tufts University, 4 Colby Street, Medford, MA 02155 (United States); Pyda, Marek [Department of Chemistry, The University of Technology, Rzeszow, 35959 Rzeszow (Poland); Cebe, Peggy, E-mail: peggy.cebe@tufts.edu [Department of Physics and Astronomy, Tufts University, 4 Colby Street, Medford, MA 02155 (United States)

    2009-08-10

    Binary blends of poly(ethylene terephthalate) with poly(lactic acid), PET/PLA, were studied by differential scanning calorimetry and X-ray scattering. The PET/PLA blends, prepared by solution casting, were found to be miscible in the melt over the entire composition range. Both quenched amorphous and semicrystalline blends exhibit a single, composition dependent glass transition temperature. We report the non-isothermal crystallization of (a) PET, with and without the presence of PLA crystals and (b) PLA, with and without the presence of PET crystals. PET can crystallize in all blends, regardless of whether PLA is amorphous or crystalline, and degree of crystallinity of PET decreases as PLA content increases. In contrast, PLA crystallization is strongly affected by the mobility of the PET fraction. When PET is wholly amorphous, PLA can crystallize even in 70/30 blends, albeit weakly. But when PET is crystalline, PLA cannot crystallize when its own content drops below 0.90. These different behaviors may possibly be related to the tendency of each polymer to form constrained chains, i.e., to form the rigid amorphous fraction, or RAF. PET is capable of forming a large amount of RAF, whereas relatively smaller amount of RAF forms in PLA. Like the crystals, the rigid amorphous fraction of one polymer component may inhibit the growth of crystals of the other blend partner.

  1. Kinetics and isotherms of Neutral Red adsorption on peanut husk

    Institute of Scientific and Technical Information of China (English)

    HAN Runping; HAN Pan; CAI Zhaohui; ZHAO Zhenhui; TANG Mingsheng

    2008-01-01

    Adsorption of Neutral Red (NR) onto peanut husk in aqueous solutions was investigated at 295 K. Experiments were carded out as function of pH, adsorbent dosage, contact time, and initial concentration. The equilibrium adsorption data were analyzed by Langmuir, Freundlich, Temkin, Dubinin-Radushkevich, and Toth isotherm models. The results indicated that the Toth and Langmuir models provided the best correlation of the experimental data. The adsorption capacity of peanut husk for the removal of NR was determined with the Langmuir and found to be 37.5 mg/g at 295 K. The adsorption kinetic data were modeled using the pseudo-first order, pseudo-second order, and intra-particle diffusion kinetic equations. It was seen that the pseudo-first order and pseudo-second order kinetic equations could describe the adsorption kinetics. The intraparticle diffusion model was also used to express the adsorption process at the two-step stage. It was implied that peanut husk may be suitable as adsorbent material for adsorption of NR from aqueous solutions.

  2. Diagnosis of brugian filariasis by loop-mediated isothermal amplification.

    Science.gov (United States)

    Poole, Catherine B; Tanner, Nathan A; Zhang, Yinhua; Evans, Thomas C; Carlow, Clotilde K S

    2012-01-01

    In this study we developed and evaluated a Brugia Hha I repeat loop-mediated isothermal amplification (LAMP) assay for the rapid detection of Brugia genomic DNA. Amplification was detected using turbidity or fluorescence as readouts. Reactions generated a turbidity threshold value or a clear visual positive within 30 minutes using purified genomic DNA equivalent to one microfilaria. Similar results were obtained using DNA isolated from blood samples containing B. malayi microfilariae. Amplification was specific to B. malayi and B. timori, as no turbidity was observed using DNA from the related filarial parasites Wuchereria bancrofti, Onchocerca volvulus or Dirofilaria immitis, or from human or mosquito. Furthermore, the assay was most robust using a new strand-displacing DNA polymerase termed Bst 2.0 compared to wild-type Bst DNA polymerase, large fragment. The results indicate that the Brugia Hha I repeat LAMP assay is rapid, sensitive and Brugia-specific with the potential to be developed further as a field tool for diagnosis and mapping of brugian filariasis. PMID:23272258

  3. STAR: a simple TAL effector assembly reaction using isothermal assembly.

    Science.gov (United States)

    Gogolok, Sabine; Garcia-Diaz, Claudia; Pollard, Steven M

    2016-09-12

    Transcription activator-like effectors (TALEs) contain modular programmable DNA binding domains. Fusing TALEs with effector domains creates synthetic transcription factors (TALE-TFs) or nucleases (TALENs), enabling precise gene manipulations. The construction of TALEs remains challenging due to their repetitive sequences. Here we report a simple TALE assembly reaction (STAR) that enables individual laboratories to generate multiple TALEs in a facile manner. STAR uses an isothermal assembly ('Gibson assembly') that is labour- and cost-effective, accessible, rapid and scalable. A small 68-part fragment library is employed, and the specific TALE repeat sequence is generated within ~8 hours. Sequence-verified TALENs or TALE-TF plasmids targeting 17 bp target sequences can be produced within three days, without the need for stepwise intermediate plasmid production. We demonstrate the utility of STAR through production of functional TALE-TFs capable of activating human SOX2 expression. STAR addresses some of the shortcomings of existing Golden Gate or solid-phase assembly protocols and enables routine production of TALE-TFs that will complement emerging CRISPR/Cas9-based reagents across diverse applications in mammalian stem cell and synthetic biology.

  4. Isothermal and isochronal annealing experiments on irradiated commercial power VDMOSFETs

    International Nuclear Information System (INIS)

    The paper presents results of isothermal and isochronal annealing experiments on several types of gamma-ray irradiated commercial N- and P-channel power VDMOSFETs. Transistors were characterized for their threshold voltage shift and densities of radiation-induced oxide-trap charge and interface traps. The results show that the temperature enhances interface trap formation and oxide-trap charge decay rates, but also contributes to the passivation of interface traps. The study demonstrates that formation and passivation of interface traps are simultaneous processes. At certain conditions (lower temperature and/or positive bias) interface-trap formation dominates. Oppositely, at other conditions (higher temperature and/or negative bias) passivation is predominant. However at some conditions there is a complex interplay between formation and passivation of interface traps, resulting in interface traps increase followed by decrease at later annealing times. No model for interface trap post-irradiation behavior can explain this effect better than the recently proposed H-W model

  5. Isothermal heat measurements of TBP-nitric acid solutions

    International Nuclear Information System (INIS)

    Net heats of reaction were measured in an isothermal calorimeter for TBP/HNO3 solutions at ambient pressure and temperatures above 100 degrees C. Carbon and nitrogen balances were performed giving the reaction stoichiometry. Rate expressions were derived and rate constants determined for both the single and two phase systems which included mass lost from the reacting system by evaporation. This mathematical model was fit to the experimental data (including the measured net heat and off-gas rate) gathered over a wide range of conditions. The oxidation rate constant was determined to be 5.4E-4 min-1 at 110 degrees C for an open open-quotes ventedclose quotes system as compared to >1E-3min-1 in a closed system. The heat released per unit material oxidized was also reduced due to a decrease in dissolved oxidants and an inefficient reduction of HNO3. Oxidation in the organic phase was found to be first order in nitric acid and pseudo-zero order in butylnitrate and water

  6. Mise au point d'un nouvel appareil de "distillation isotherme" Disterm Development of Distherm, a New Isothermal Distillation Apparatus

    Directory of Open Access Journals (Sweden)

    Mouton M.

    2006-11-01

    Full Text Available Les études analytiques de distillats pétroliers d'intervalles d'ébullition élevés doivent être réalisées sur des produits préparés dans des conditions de distillation extrêmement douces, de manière à conserver intactes toutes les espèces chimiques initialement contenues dans le pétrole brut en l'état. Pour répondre à cet objectif, le Comité de Distillation du GEC (Groupe d'Études Concertées sur l'analyse des fractions lourdes du pétrole, réunissant Compagnie Francaise de Raffinage (CFR, Société Nationale Elf Aquitaine (SNEA et Institut Français du Pétrole (IFP a mis au point un schéma de préparation spécial de ces distillats, faisant appel à des techniques de distillation continue, de type « isotherme» et « moléculaire ». Dans ce cadre, le Comité de Distillation du GEC a été amené à développer un nouvel appareillage de distillation x isotherme », permettant de réduire, sans craquage, tout pétrole brut jusqu'à une température maximale comprise entre 350 et 380 °C. On décrit dans cet article ce nouvel ensemble de distillation, ainsi que ses conditions opératoires de fonctionnement. On y donne aussi un aperçu de la précision de la méthode de distillation réalisable avec cet appareil, ainsi que de la qualité de fractionnement obtenu.Enfin, à l'aide de quelques exemples particuliers, on montre que le domaine d'application de l'appareil peut être étendu à des produits autres que des pétroles bruts. Analytical examinations of high-boiling-range petroleum distillates must be made with products prepared under extremely mild distillation conditions so as ta maintain intact all the chemical species initially present in the original crude oil.

  7. Rural migration and health care

    DEFF Research Database (Denmark)

    Svendsen, Gunnar Lind Haase; Jensen, Marit Vatn

    This literature study focuses on possible links between access to health services and migration in rural areas. Why do people move to or from rural areas or why do they stay? What determines where people settle? And, in this context, do local health care services play an important or minor role......, or no role at all? First, the paper reports on key findings from rural migration studies, in order to shed light on two migration trends: urbanization and counter-urbanization. Then we take a closer look on settlement preferences in rural areas, including the impact of health care facilities. Finally, we end...... up with a more deepgoing review of the relatively small number of studies, which explicitly deal with settlement preferences related to access to health care....

  8. Neurobiology of Monarch Butterfly Migration.

    Science.gov (United States)

    Reppert, Steven M; Guerra, Patrick A; Merlin, Christine

    2016-01-01

    Studies of the migration of the eastern North American monarch butterfly (Danaus plexippus) have revealed mechanisms behind its navigation. The main orientation mechanism uses a time-compensated sun compass during both the migration south and the remigration north. Daylight cues, such as the sun itself and polarized light, are processed through both eyes and integrated through intricate circuitry in the brain's central complex, the presumed site of the sun compass. Monarch circadian clocks have a distinct molecular mechanism, and those that reside in the antennae provide time compensation. Recent evidence shows that migrants can also use a light-dependent inclination magnetic compass for orientation in the absence of directional daylight cues. The monarch genome has been sequenced, and genetic strategies using nuclease-based technologies have been developed to edit specific genes. The monarch butterfly has emerged as a model system to study the neural, molecular, and genetic basis of long-distance animal migration. PMID:26473314

  9. Brownian Motion in Planetary Migration

    CERN Document Server

    Murray-Clay, R A; Murray-Clay, Ruth A.; Chiang, Eugene I.

    2006-01-01

    A residual planetesimal disk of mass 10-100 Earth masses remained in the outer solar system following the birth of the giant planets, as implied by the existence of the Oort cloud, coagulation requirements for Pluto, and inefficiencies in planet formation. Upon gravitationally scattering planetesimal debris, planets migrate. Orbital migration can lead to resonance capture, as evidenced here in the Kuiper and asteroid belts, and abroad in extra-solar systems. Finite sizes of planetesimals render migration stochastic ("noisy"). At fixed disk mass, larger (fewer) planetesimals generate more noise. Extreme noise defeats resonance capture. We employ order-of-magnitude physics to construct an analytic theory for how a planet's orbital semi-major axis fluctuates in response to random planetesimal scatterings. To retain a body in resonance, the planet's semi-major axis must not random walk a distance greater than the resonant libration width. We translate this criterion into an analytic formula for the retention effi...

  10. The International-Migration Network

    CERN Document Server

    Fagiolo, Giorgio

    2012-01-01

    This paper studies international migration from a complex-network perspective. We define the international-migration network (IMN) as the weighted-directed graph where nodes are world countries and links account for the stock of migrants originated in a given country and living in another country at a given point in time. We characterize the binary and weighted architecture of the network and its evolution over time in the period 1960-2000. We find that the IMN is organized around a modular structure characterized by a small-world pattern displaying disassortativity and high clustering, with power-law distributed weighted-network statistics. We also show that a parsimonious gravity model of migration can account for most of observed IMN topological structure. Overall, our results suggest that socio-economic, geographical and political factors are more important than local-network properties in shaping the structure of the IMN.

  11. Evaluation of theoretical and empirical water vapor sorption isotherm models for soils

    Science.gov (United States)

    Arthur, Emmanuel; Tuller, Markus; Moldrup, Per; de Jonge, Lis W.

    2016-01-01

    The mathematical characterization of water vapor sorption isotherms of soils is crucial for modeling processes such as volatilization of pesticides and diffusive and convective water vapor transport. Although numerous physically based and empirical models were previously proposed to describe sorption isotherms of building materials, food, and other industrial products, knowledge about the applicability of these functions for soils is noticeably lacking. We present an evaluation of nine models for characterizing adsorption/desorption isotherms for a water activity range from 0.03 to 0.93 based on measured data of 207 soils with widely varying textures, organic carbon contents, and clay mineralogy. In addition, the potential applicability of the models for prediction of sorption isotherms from known clay content was investigated. While in general, all investigated models described measured adsorption and desorption isotherms reasonably well, distinct differences were observed between physical and empirical models and due to the different degrees of freedom of the model equations. There were also considerable differences in model performance for adsorption and desorption data. While regression analysis relating model parameters and clay content and subsequent model application for prediction of measured isotherms showed promise for the majority of investigated soils, for soils with distinct kaolinitic and smectitic clay mineralogy predicted isotherms did not closely match the measurements.

  12. Retirement migration and military retirement

    International Nuclear Information System (INIS)

    This report addresses questions relevant to a socioeconomic assessment system for southern Nevada. They point to an understanding of the magnitude of impacts which may occur if the Yucca Mountain Project were to affect the decision-making process which leads these groups to migrate to southern Nevada. This is an important but somewhat elusive topic lacking in standard data sources. However, the topic may be addressed and analyzed systematically. This report presents the results of efforts to develop a data base and begin development of a model to address the migration, income and expenditure dimensions of these groups. 1 fig., 62 tabs

  13. Rural migration in southern Nevada

    International Nuclear Information System (INIS)

    This study reviews the history of migration in two rural counties in Southern Nevada. It is part of a larger study about the impact of a proposed high-level nuclear waste repository on, in and out-migration patterns in the state. The historical record suggests a boom and bust economic cycle has predominated in the region for the past century creating conditions that should be taken into account, by decision makers, when ascertaining the long-term impacts of the proposed repository

  14. Women’s football migration

    DEFF Research Database (Denmark)

    Agergaard, Sine

    What is intriguing about women’s football as a cultural phenomenon is that unlike men’s football the finances and media interest for the game are sparse. Nevertheless we have found that migration of female football players is growing steadily and women’s football is becoming global in nature....... The question is then what drives this globalization process? According to our study of women’s football migration into Scandinavia, one of the centers of women’s football, transnational networks play a crucial role in mobilizing global migratory moves. Using the concept of friends-of-friends networks from Bale...

  15. COMPARATIVE STUDY OF LINEARIZED AND NON-LINEARIZED MODIFIED LANGMUIR ISOTHERM MODELS ON ADSORPTION OF ASPHALTENE ONTO MINERAL SURFACES

    OpenAIRE

    Mohammadi, M; AMERI SHAHRABI M.J.; Sedighi, M.

    2012-01-01

    In this paper, the Langmuir isotherm, originally derived for the adsorption of asphaltene extracted from shale oil and dissolved in toluene on Kaolin, Smectite, Fluorite and Hematite, was modified to fit the adsorption isotherm. The modified Langmuir isotherm parameters obtained from the four linear equations using the linear method differed. The aim of the proposed modification is based on the fact that direct application of the Langmuir isotherm often leads to poor data fitting. In the pres...

  16. [International migration in the Americas: intraregional migration grows].

    Science.gov (United States)

    Zlotnik, H

    1992-01-01

    The principal destinations for intraregional migrants in South America in recent decades have been Argentina, Brazil, and Venezuela, while in North America the U.S. has exerted a growing attraction since 1965. Intraregional migration in Latin America has been irregular and difficult to quantify, and reliable statistics on migratory flows are nonexistent. Census data indicate that most migration to Argentina and Brazil occurred before 1960, while most migration to Venezuela occurred during the 1970s. Between 1960 and 1980, the proportion of migrants from other Latin American countries showed a tendency to increase, despite decreases in the overall level of immigration. The effect of the economic crisis of the 1980s on immigration from Latin American countries will become more apparent as census data for the 1990s become available. Selectivity according to country of origin is an important characteristic of intraregional migration in South America. The U.S. has, however, been the principal destination of Latin American migrants for the past three decades. Between 1965 and 1991 the U.S. granted resident status to more than 7.4 million persons of Latin American and Caribbean origin, and they constituted 47% of immigrants during those years. The great majority of the Latin American immigrants in the U.S. are Mexican. The 3.5 million Mexicans admitted to the U.S. as immigrants between 1965 and 1991 accounted for 22% of all immigrants during this period. PMID:12158068

  17. Migrations et relations internationales Migration and international relations. The pitfalls of managing international migration multilaterally

    Directory of Open Access Journals (Sweden)

    Hélène Thiollet

    2010-12-01

    Full Text Available Les migrations internationales sont aujourd’hui un des enjeux majeurs de la gouvernance globale. Elles restent pourtant l’objet de politiques régaliennes où dominent les accords bilatéraux sans que s’impose un régime de gestion multilatéral. Les migrations sont une des pierres d’achoppement du multilatéralisme et leur gestion est revendiquée par les États comme une dimension inaliénable de leur souveraineté (économique, territoriale…. Les institutions multilatérales tentent de proposer des modalités de gouvernance multilatérale des migrations comme phénomène social global. À l’Onu, le Haut commissariat aux réfugiés (Hcr s’occupe des réfugiés et l’Organisation internationale du travail (Oit des migrants en leur qualité de travailleurs. La Banque mondiale et le Fmi sont particulièrement actifs sur la question des migrations et des transferts financiers qui les accompagnent alors que l’Unicef s’intéresse aux conséquences sociales de la mobilité sur les familles dans les pays d’origine ou d’accueil. L’Organisation internationale des migrations travaille quant à elle en marge de l’Onu. L’Onu n’est pas parvenu à imposer la Convention sur les droits des migrants de 1990 et ne parvient pas à faire émerger une ligne d’action collective dans l’arène multilatérale sur la question migratoire. Pourtant, dans la sphère onusienne et au-delà, les organisations internationales négocient l’émergence d’une agence spécialisée dans les migrations. À partir de la stratégie historique du Hcr dans le champ multilatéral et d’une innovation juridique récente – le concept de « migrations mixtes » –, on décrit une des tentatives de gestion juridique de la mobilité forcée et volontaire. En 2006, le concept émerge avec l’expérience des migrations sub-sahariennes à travers la Méditerranée. On s’intéresse ici à son utilisation dans le cas de migrations depuis la corne de

  18. The Role of Remittances in Migration Decision: Evidence from Turkish Migration

    OpenAIRE

    Akkoyunlu, Sule; Siliverstovs, Boriss

    2007-01-01

    In this study we analyse the impact of workers' remittances on the decision to migrate by means of cointegration analysis. In traditional migration theories, especially in human capital models, the decision to migrate is based upon comparison of expected future incomes in the sending and the receiving countries adjusted for the cost of migration. By contrast, the new economics of labour migration suggests that the migration decision is made jointly by the migrant and his family. One important...

  19. [Family reunification, family-formation migration, and return migration of Turks and Moroccans].

    Science.gov (United States)

    De Beer, J; Kuijper, H; Noordam, R

    1991-01-01

    The authors analyze migration patterns to the Netherlands from Turkey and Morocco for the period 1977-1989. Three distinct phases emerge: labor migration, family-reunification migration, and family-formation migration. The rise in migration from Turkey and Morocco during the second half of the 1980s is attributed to family-formation migration, which is defined as a member of the second generation marrying a partner from the country of origin. (SUMMARY IN ENG)

  20. Non-isothermal dispersed phase of particles in turbulent flow

    Science.gov (United States)

    Pandya, R. V. R.; Mashayek, F.

    2003-01-01

    In this paper we consider, for modelling and simulation, a non-isothermal turbulent flow laden with non-evaporating spherical particles which exchange heat with the surrounding fluid and do not collide with each other during the course of their journey under the influence of the stochastic fluid drag force. In the modelling part of this study, a closed kinetic or probability density function (p.d.f.) equation is derived which describes the distribution of position x, velocity v, and temperature [theta] of the particles in the flow domain at time t. The p.d.f. equation represents the transport of the ensemble-average (denoted by [left angle bracket] [right angle bracket]) phase-space density [left angle bracket]W(x, v, [theta], t)[right angle bracket]. The process of ensemble averaging generates unknown terms, namely the phase-space diffusion current j = [beta]v[left angle bracket]u[prime prime or minute]W[right angle bracket] and the phase-space heat current h = [beta][theta][left angle bracket]t[prime prime or minute]W[right angle bracket], which pose closure problems in the kinetic equation. Here, u[prime prime or minute] and t[prime prime or minute] are the fluctuating parts of the velocity and temperature, respectively, of the fluid in the vicinity of the particle, and [beta]v and [beta][theta] are inverse of the time constants for the particle velocity and temperature, respectively. The closure problems are first solved for the case of homogeneous turbulence with uniform mean velocity and temperature for the fluid phase by using Kraichnan’s Lagrangian history direct interaction (LHDI) approximation method and then the method is generalized to the case of inhomogeneous flows. Another method, which is due to Van Kampen, is used to solve the closure problems, resulting in a closed kinetic equation identical to the equation obtained by the LHDI method. Then, the closed equation is shown to be compatible with the transformation constraint that is proposed by