The H-Dexchange reaction has been measured with the D2-H2O system, for Rhodobacter capsulatus JP91, which lacks the hupSL-encoded hydrogenase, and R. capsulatus BSE16, which lacks the HupUV proteins....Full Text Available
This article presents a humidification-dehumidification (H.D.) process suitable for desalination of sea- and brackish water. The work correlated performance characteristics of the combination of different components in such a loop. Water yield, energy requirement and design data are evaluated as functions of different parameters. The investigation covered water to air mass ratios ranging from 60 to 80, concentration ratios between 2 and 5, at a temperature difference of between 10 and 16 C, along the liquid for dehumidification. The results showed that 76% of energy consumed in the humidifier is recovered by condensation. Increase of the concentration ratio to 5 can reduce the make-up water and rejected brine by about 58% and 24% respectively. Cost calculations show that the H.D. process has significant potential as an alternative for small capacity desalination plants and permits to operate systems as small as 10 m[sup ...
This paper illustrates how the techniques developed by the authors for capital cost targeting of massexchange networks can be applied to determination of capital investment targets for reduction in effluent for existing systems involving massexchange. The results is an impact diagram which shows the relationship between effluent reduction and capital investment, indicating a region of limiting return on investment as well as the maximum possible reduction in effluent. (au)
The effect of varying pD(11-13,7) on the reaction of hydrogen with (Co/sup 11/(CN)/sub 5/)/sup 3/- in deuterium oxide has been studied by using infrared spectroscopy to determine the ratio of (Co/sup 111/(CN)/sub 5/X)/sup 3/- (X=H,D) in the solids precipitated from the steady state under hydrogen. The results show that the uptake of hydrogen does not liberate a free proton and that the rate of (Co/sup 111/(CN)/sub 5/H)/sup 3/- -D/sub 2/,0 exchange increases with pD but becomes pD independent at pD 7 greater than 13,5.
The effect of heat transfer is described from heat exchange tubes of a horizontal steam generator on the distribution of primary water to the individual tubes of the tube bundle. It is shown that in a broad interval of mass flow rates and lengths of heat exchange tubes, the simplified method of calcualtion, i.e., calculation of the distribution of primary water into heat exchange tubes neqlecting the changes of physical properties of water along the heat exchange tubes, will yield sufficiently accurate results.
The effect of heat transfer is described from heat exchange tubes of a horizontal steam generator on the distribution of primary water to the individual tubes of the tube bundle. It is shown that in a broad interval of mass flow rates and lengths of heat exchange tubes, the simplified method of calcualtion, i.e., calculation of the distribution of primary water into heat exchange tubes neqlecting the changes of physical properties of water along the heat exchange tubes, will yield sufficiently accurate results. (author).
We explore the structure of a new family gauge symmetry U(3) and show its experimental signatures to search for. U(3) gauge bosons obviate an unwelcome deviation of the charged lepton mass formula with the running masses from that with the pole masses. The current structure of this model leads to flavor number violations via exchange of extra gauge bosons. We obtain bounds on the masses of the gauge bosons from rare kaon decay searches and muonium-antimuonium oscillation searches. We propose attractive signatures at LHC and lepton colliders and discuss feasibility of their discovery.
The first successful observation of double analog states in "8"8Zr and "9"0Mo has been made by means of the (#pi#"+,#pi#"-) pion double charge exchange (DCX) reaction. The systematics of the (N - Z) and the A dependence of analog DCX, made possible by these observations, is discussed. (orig.).
The results of calculated and experimental investigation of interphase isotopic exchange efficiency in countercurrent columns are given when separation processes of isotope mixtures are taken place with use of liquid-solid systems. Effect of liquid phase flow on transfer unit height in ion exchange separation of boron, lithium, nitrogen isotopes is considered. 40 refs.; 5 figs.
Least-squares analyses were performed on a set of atomic masses using standard and generalized senaiempirical mass laws. Presumably because of errors in the assured form of the standand mass law, its least-squares coefficients can be determined at best to an accuracy of about 10%, and masses are predicted with an uncertainty of several Mev/c/sup 2/. The standard mass law was generalized by addition of shell effect and deformation terms. While the least-squares fitting of the generalized mass law is better than for the standard mass law, it is still not possible to predict atomic masses to an accuracy better than a few Mev/c/sup 2/. The nuclear deformations and the well depth . of the nuclear interaction obtained from the additional mass-law terms are in reasonable agreement ...
Fractionation of isotopes of the alkali metals and the alkaline earth metals in ion exchange chromatography of their chlorides was studied. The heavier isotopes of potassium and rubidium were found to be preferentially fractionated into the ion exchanger phase while the lighter isotopes of lithium, magnesium, calcium and strontium were enriched in the exchanger phase. This can be interpreted as a resultant of the relative significance of isotope effect upon dehydration and isotope effect accompanying the phase change of the hydrated metal ion. Found was no evidence of anomalous isotope effect attributable to the odd-even difference in mass number of isotopes. Based on the spectroscopic and solution chemical data (experimental and theoretical), the isotopic reduced partition function ratios of the hydrated alkaline metal ions and stretching force constants of metal ion-hydrating water bonds were ...
We derive the exchange currents of pseudoscalar, vector, and scalar mesons from Feynman diagrams, and use them to calculate the magnetic form factors of nucleon and ?(1232). The magnetic moments and electromagnetic radii are obtained by using those form factors and the parameters determined from the masses of nucleon and ?(1232). We find the magnetic moments and electromagnetic radii of nucleon and ?(1232) can be produced very well in the extended Goldstone-Boson-exchange model in which all of pseudoscalar, vector, and scalar meson nonet are included. The magnetic moments of ?(1232) are closer to experiment values and results from lattice calculation than the results obtained by the model without other mesons except for pion and sigma.
This paper reports that fluidelastic instability is the most important vibration excitation mechanism for heat exchanger tube bundles subjected to cross-flow. Most of the available data on this topic have been reviewed from the perspective of the designer. Uniform definitions of critical flow velocity for instability, damping, natural frequency and hydrodynamic mass were used. Nearly 300 data points were assembled. The authors found that only data from experiments where all tubes are free to vibrate are valid form a design point of view. In liquids, fluid damping is important and should be considered in the formulation of fluidelastic instability. From a practical design point of view, we conclude that fluidelastic instability may be expressed simply in term of dimensionless flow velocity and dimensionless mass-damping. There is no advantage in considering more sophisticated models at this time. Practical design guidelines ...
This paper advances hypotheses on the chemistry of the interaction of thorium and yttrium with organic-inorganic salts of molybdenum polyacids. On the basis of an analysis of the data of an adsorption experiment and the quantitative relationships that follow from the law of mass action, it is shown that thorium is absorbed by the solid phase by coprecipitation with the participation of complex formation, while the coprecipitation of yttrium with salts of polyacids is due to a reaction of ion exchange chemisorption.
The two-fluid model representation for calculations of two-phase flow characteristics in the FBR fuel pin bundles with liquid metal cooling is presented and analysed. Two conservation equations systems of the mass, momentum and energy have been written for each phase. Components accounted the mass-, momentum- and heat transfer throughout the interface occur in the macro-field equations after the averaging procedure realisation. The pattern map and correlations for two-fluid model in vertical liquid metal flows are presented. The description of processes interphase mass- and heat exchange and interphase friction is determined by the two-phase flow regime. The opportunity of the liquid metal two-phase flow regime definition is analysed. (author)
In this Brief Report, we consider dijet production at {gamma}{gamma} colliders as a probe of recently proposed, large extra-dimensional gravity models. The exchange of virtual, spin-2 graviton towers (Kaluza-Klein excitations) significantly modifies the cross section, as compared to the standard model predictions. We find that, in order to maximize the value of the effective scale that can be probed at a given center-of-mass energy, a very severe p{sub T} cut should be applied; in general, a p{sub T} equal to approximately 46% of the e{sup +}e{sup -} beam energy gives the highest reach. We find that we can probe the effective mass scale from about 2.7 TeV to 11.1 TeV, depending on the center-of-mass energy and assumptions about the model. (c) 2000 The American Physical Society.
In this Brief Report, we consider dijet production at #gamma##gamma# colliders as a probe of recently proposed, large extra-dimensional gravity models. The exchange of virtual, spin-2 graviton towers (Kaluza-Klein excitations) significantly modifies the cross section, as compared to the standard model predictions. We find that, in order to maximize the value of the effective scale that can be probed at a given center-of-mass energy, a very severe p_T cut should be applied; in general, a p_T equal to approximately 46% of the e"+e"- beam energy gives the highest reach. We find that we can probe the effective mass scale from about 2.7 TeV to 11.1 TeV, depending on the center-of-mass energy and assumptions about the model. (c) 2000 The American Physical Society
A procedure was developed for separating rubidium from irradiated aluminum encapsulated uranium. The separations procedure produces a final ultra-high purity RbCl product for subsequent high performance mass spectrometric analysis. The procedure involves first removing most of the macro-components and fission products by strong base anion exchange using, first, concentrated HCl, then oxalic acid media and second, selectively separating rubidium from alkaline-earth ions and other alkali-metal ions, including cesium, using Bio-Rex-40 cation-exchange resin. The resultant RbCl is then put through a final vacuum sublimation step. Ultra-pure reagents and specially clean glassware are used throughout the procedure to minimize contamination by naturally-occurring rubidium.
A procedure was developed for separating rubidium from irradiated aluminum encapsulated uranium. The separations procedure produces a final ultra-high purity RbCl product for subsequent high performance mass spectrometric analysis. The procedure involves first removing most of the macro-components and fission products by strong base anion exchange using, first, concentrated HCl, then oxalic acid media and second, selectively separating rubidium from alkaline-earth ions and other alkali-metal ions, including cesium, using Bio-Rex-40 cation-exchange resin. The resultant RbCl is then put through a final vacuum sublimation step. Ultra-pure reagents and specially clean glassware are used throughout the procedure to minimize contamination by naturally-occurring rubidium.
We investigate the semihard production of neutral pseudoscalar and tensor mesons in high-energy [gamma][gamma] collisions (M=P=[pi][sup 0], [eta], [eta]' or M=T=a[sub 2], f[sub 2], f[sub 2]'). We deal with the exclusive [gamma][gamma][yields]MM' or semi-exclusive [gamma][gamma][yields]MX reactions (X is the hadron jet with not too large mass). The considered transfer momenta are small in comparison with the photon energies and they are large in comparison with the confinement scale. The amplitudes of these processes are determined by the odderon exchange, i.e. three-gluon exchange in the lowest order of perturbative QCD. The cross sections are calculated in this approximation. The possibility of measurements at LEP and at future [gamma][gamma] colliders is discussed. (orig.).
At the quark level there are basically two types of contributions of R-parity violating supersymmetry (Rep SUSY) to neutrinoless double beta decay: the short-range contribution involving only heavy virtual superpartners and the long-range one with the virtual squark and neutrino. Hadronization of the effective operators, corresponding to these two types of contributions, may in general involve virtual pions in addition to close on-mass-shell nucleons. From the previous studies it is known that the short-range contribution is dominated by the pion exchange. In the present paper we show that this is also true for the long-range Rep SUSY contribution. Therefore, we conclude that the Rep SUSY contributes to the neutrinoless double beta decay dominantly via charged pion exchange between the decaying nucleons.
The object of the present study is to develop a high performance evaporator for automotive air conditioner. The experiment has been conducted on evaporative heat transfer coefficient inside a plate type heat exchanger with a sharp 180-degree turn flow. The test plates have different formed surface, cross-ribboned channel and elliptical-ribbed channel. Also experimental study has been performed to determine optimal design in elliptical-ribbed plate heat exchanger with different turn clearance. In addition to the above experiments, refrigerant behavior and surface temperature distribution in the plate heat exchanger were observed using color thermo viewer(infrared thermometer). In this experiment, working fluid was used R-12 and test conditions were as follows : (1) saturation pressure of 2,116 kg/cm{sup 2}, (2) mass fluxes of 40 to 70 kg/m{sup 2} s, (3) heat fluxes of 4,500 to 7,300 W/m{sup 2}, (4) inlet ...
This project dealt with use of condensing heat exchangers to recover water vapor from flue gas at coal-fired power plants. Pilot-scale heat transfer tests were performed to determine the relationship between flue gas moisture concentration, heat exchanger design and operating conditions, and water vapor condensation rate. The tests also determined the extent to which the condensation processes for water and acid vapors in flue gas can be made to occur separately in different heat transfer sections. The results showed flue gas water vapor condensed in the low temperature region of the heat exchanger system, with water capture efficiencies depending strongly on flue gas moisture content, cooling water inlet temperature, heat exchanger design and flue gas and cooling water flow rates. Sulfuric acid vapor condensed in both the high temperature and low temperature regions of the heat transfer apparatus, ...
Patients suffering from depression frequently display hyperactivity of the hypothalamic-pituitary-adrenal axis (HPA) resulting in elevated cortisol levels. One main symptom of this condition is anhedonia. There is evidence that exercise training can be used as a rehabilitative intervention in the treatment of depressive disorders. In this scenario, the aim of the present study was to assess the effect of an aerobic exercise training protocol on the depressive-like behavior, anhedonia, induced by repeated dexamethasone administration. The study was carried out on adult male Wistar rats randomly divided into four groups: the "control group" (C), "exercise group" (E), "dexamethasone group" (D) and the "dexamethasone plus exercise group" (DE). The exercise training consisted of swimming (1 h/d, 5 d/wk) for 3 weeks, with an overload of 5% of the rat body weight. Every day rats were injected with either dexamethasone (D/DE) or saline solution (C/E). Proper positive ...
This paper describes the comprehensive modeling method of fluid and heat flows in the hydrological system. Based upon the concept that the hydrological system is composed of the air-water 2-phase fluids, and the rock phase, various natural processes are modeled including surface/subsurface 2-phase mass transfer, heat exchanges between fluid phases, between fluid and solid phases, and sensible/latent heat exchanges on the ground surface. A field-oriented numerical simulator is developed, in which a set of governing equations is solved for different variables on the surface and in subsurface regions, respectively. Results of an experimental study are presented, in which transient formulation of heat exchange between fluid/solid phases is examined through matching of the observation and calculated performances. (author)
This paper describes the comprehensive modeling method of fluid and heat flows in the hydrological system. Based upon the concept that the hydrological system is composed of the air-water 2-phase fluids, and the rock phase, various natural processes are modeled including surface/subsurface 2-phase mass transfer, heat exchanges between fluid phases, between fluid and solid phases, and sensible/latent heat exchanges on the ground surface. A field-oriented numerical simulator is developed, in which a set of governing equations is solved for different variables on the surface and in subsurface regions, respectively. Results of an experimental study are presented, in which transient formulation of heat exchange between fluid/solid phases is examined through matching of the observation and calculated performances. (author)
Compact heat exchangers have traditionally found wide application in the transportation industry, where they are used as evaporators and condensers in vapor compression cycles for air conditioning and refrigeration. Such heat exchangers possess numerous attractive features including high thermal effectiveness, small size, low weight, design flexibility, and pure counterflow, and they can accommodate multiple streams. Today, there is a widespread interest in expanding the range of application of compact heat exchangers to include phase-change heat transfer in the process industries, among others. An overall objective of this effort is to provide the basis for establishing design technology in this area. In the present study, small channel flow boiling heat transfer was extended to a rectangular channel (4.06 {times} 1.70 mm) using refrigerant 12 (R-12). As with the circular tube studies, the flow channel wall was ...
The aim of this article was to investigate the interactions of metal cations in aqueous solutions with the biomass of the freshwater macroalga Vaucheria sp. This problem is important when elaborating new applications of biosorption, e.g. the production of mineral feed additives for livestock from the biomass of algae enriched with microelement ions. Potentiometric titration was applied as a quick and cheap screening test to search for new efficient biosorbents. It revealed a variety of functional groups capable of cation exchange on the macroalgal surface, including carboxyl, phosphate, hydroxyl or amino groups. Fourier transform infrared spectroscopy on natural and chromium-loaded Vaucheria sp. confirmed that carboxyl groups played a dominant role in the biosorption. The study also showed that Ca(II), Na(I), K(I), and Mg(II) ions were released from the biomass after biosorption of Cu(II), Mn(II), Zn(II), and Co(II) ions, indicating that ion ...
A means of determination of a ctive hydrogen of hydroxyl, carboxyl, sulfhydryl, amino, amido and sulfonamido groups by chemical ionization mass spectrometry using ammonia and trideuterioammonia as reagent gases is described. The method is based on exchange of active hydrogen for deuterium occurring during the chemical ionization process using trideuterioammonia, with comparison of m/z for ammonium adduct [M + NH1]+ and trideuterioammonium adduct [M--nH + nD + ND4]+, or of protonated molecular ion [M + H]+ and deuteronated molecular ion [M--nH + nD + D]+ yielding the number of active hydrogens. Applications have been made to several classes of biologically important compounds. PMID:427257
We propose a novel method for ultrasensitive isotope analysis that combines magnetic mass selection, resonant charge-exchange neutralization, and resonant laser ionizaion. Our method attains high isotopic abundance selectivity by means of continuous multistage separation of ions stored in a small ring. For the environmentally interesting case of /sup 90/Sr versus /sup 88/Sr we estimate that sensitivity better than 10/sup -15/ for a throughput of 10/sup 13/ atoms/sec and an efficiency (after the ion source) greater than 10% are readily achievable.
We revisit the case of a light neutralino LSP in the framework of the MSSM. We consider a model with eleven free parameters. We show that all scenarios where the annihilation of light neutralinos rely mainly on the exchange of a light pseudoscalar are excluded by direct detection searches and by Fermi measurements of the gamma-flux from dwarf spheroidal galaxies. On the other hand, we find scenarios with light sleptons that satisfy all collider and astroparticle physics constraints. In this case, the lower limit on the LSP mass is 12.6 GeV. We discuss how the parameter space of the model will be further probed by new physics searches at the LHC.
The effects of temperature and the use of macroreticular resins were studied in lithium isotope separation by an ion-exchange method. The isotope separation factors obtained decreased by increasing the temperature, and the factors for macroreticular resins were identical with those for the usual gel-type resins. However, the performance of isotope separation per unit band length in displacement chromatography was found to be improved by increasing the temperature and using macroreticular resins, because accelerating the interphase mass transfer caused the reduction of HETP (Height Equivalent to a Theoretical Plate).
Flow-induced vibration is an important concern to the designers of heat exchangers subjected to high flows of gases or liquids. Two-phase cross-flow occurs in industrial heat exchangers, such as nuclear steam generators, condensers, and boilers, etc. Under certain flow regimes and fluid velocities, the fluid forces result in tube vibration and damage due to fretting and fatigue. Prediction of these forces requires an understanding of the flow regimes found in heat exchanger tube bundles. Excessive vibrations under normal operating conditions can lead to tube failure. Relatively little information exists on two-phase vibration. This is not surprising as single-phase flow induced vibration; a simpler topic is not yet fully understood. Vibration in two-phase is much more complex because it depends upon two-phase flow regime, i.e. characteristics of two-phase mixture and involves an important consideration, which is the void ...
10%Pt/C catalysts were prepared by liquid reduction method. PTFE and Pt/ C catalysts were adhered to porous metal and hydrophobic Pt/C/PTFE catalysts were prepared. The structure and size of Pt crystal particles of Pt/C catalysts were analyzed by XRD, and their mean size was 3.1 nm. The dispersion state of Pt/C and PTFE was analyzed by SEM, and they had good dispersion mostly, but PTFE membrane could be observed on local parts of Pt/C/PTFE surface. Because of low hydrophobicity, Pt/C/ PTFE catalysts have low activity when the mass ratio of PTFE and Pt/C is 0.5: 1, and their catalytic activity increases markedly when the ratio is 1:1. When the ratio increases again, more Pt active sites would be covered by PTFE and interior diffusion effect would increase, which result in the decrease of catalytic activity of Pt/C/PTFE. By PTFE pretreatment of porous metal carrier, the activity of Pt/C/PTFE catalysts decreases when the mass ratio of PTFE and ...
At the Forschungszentrum Karlsruhe the HGF Strategy Fund project entitled 'Innovative Technology to Reduce Radiotoxicity' is performed which delivers an essential scientific contribution to the application oriented fundamental research for Accelerator Driven Systems (ADS). The addressed topics are in the areas of heavy liquid metal technology, thermalhydraulics and materials / corrosion. An ADS consists of three main components: an proton accelerator, a spallation target and a subcritical blanket. The strategic objective of an ADS is the transmutation of long-lived radioactive waste (plutonium, minor actinides and long-lived fission products) into short-lived isotopes or stable elements, thus closing the fuel cycle. The objective of one task of the HGF Strategy Fund Project is the numerical calculation of a closed spallation target module. In a consequent next step such a spallation target can be experimentally investigated at IKET and the numerical results can be validated. In this ...
Measurements of PEM fuel cell device performance were made with different gas inlet temperatures and relative humidity using a newly-designed test fixture. Significant improvement in device performance was observed when the fuel inlet temperature was increased above the operating temperature of the cell. These measurements were then correlated to a model to describe energy and mass transport processes. Proton exchange membrane (PEM), fuel cells--the focus of this study--use an ion conducting polymer, especially polyperfluorosulfonic acid materials. These polymer materials, when imbibed with water, exhibit solution-like properties, but because the anions are chemically bound to the polymeric structure, the electrolyte is contained. Importantly, product water removal is simplified, as electrolyte dilution is not a concern. However, the proton transport rate is a function of the polymer geometry, which is set, in part, by the polymer water ...
We study the three-nucleon force in chiral effective field theory with explicit {delta}-resonance degrees of freedom. We show that up to next-to-next-to-leading order, the only contribution to the isospin symmetric three-nucleon force involving the spin-3/2 degrees of freedom is given by the two-pion-exchange diagram with an intermediate delta, frequently called the Fujita-Miyazawa force. We also analyze the leading isospin-breaking corrections due to the delta. For that, we give the first quantitative analysis of the delta quartet mass splittings in chiral effective field theory including the leading electromagnetic corrections. The charge-symmetry breaking three-nucleon force due to an intermediate delta excitation is small, of the order of a few keV.
All measurements were made with the NBS high-pressure photoionization mass spectrometer. The fractional of C/sub 5/H/sub 10//sup +/ions in a cyclopentane-cyclohexane mixture were determined as a function of pressure in order to define the fraction of the ions which did charge exchange with cyclohexane; i.e. the fraction which remained cyclic after ionization. The data for mixtures of various compositions (2.5 to 10% cyclohexane) are summarized for measurements performed at 10.62 eV: (a) 292K, > 96% cyclic; 347 K, greater than or equal to 94% cyclic; 386 K, 84 +- 4% cyclic; and 412 K, 78 +- 6% cyclic; entropy, enthalpy, and activation energy were determined; 10.49 eV was obtained as the ionization potential of cyclopentane. 1 figure.
Heat transfer experiments were performed in the post-CHF two-phase flow regime in a vertical tube. The tube inside diameter was 7.75 mm, and the boiling fluid was R-113. The experiments were performed at steady state by means of liquid heating of the test tube. Wall superheats were maintained below 70 C for heat exchanger/steam generator application. The mass flux range of the data was 379-816 kg m{sup -2} s{sup -1}. The use of R-113 significantly extended the property range of the existing low wall-superheat data base. Experimental data are presented in tabular as well as graphical form, and the results were used with low wall-superheat data from other fluids to add generality to a predictive heat transfer correlation. (orig.)
For optimal performances, proton exchange membrane fuel cells require fine water and thermal management. Accurate modelling of the physical phenomena occurring in the fuel cell is a key issue to improve fuel cell technology. Here, an analytic steady state diphasic 2D model of heat and mass transfer is presented. Through this model, the aim of this work is to study the influence of local events on the global performances of a fuel cell. A part of the complete model is a microscopic representation of the coupling between water transport and charge transfers in the electrodes. The thickness of the liquid layer around the reactive agglomerates is deduced from the saturation. The evolution of the quantity of water within the catalyst layer is monitored and its influence on the global performanc...
We examine the virtual effects of Kaluza-Klein (KK) states on Higgs physics in universal extra dimension models. We study the partial widths {Lambda}{sub h{yields}gg}, {Lambda}{sub h{yields}{gamma}{gamma}}, and {Lambda}{sub h{yields}{gamma}Z}, which are relevant for Higgs production and detection in future collider experiments. These interactions occur at one loop in the Standard Model, as do the KK contributions. We find that the deviations induced by the KK exchanges can be significant; for one extra dimension, the gg {yields} h production rate is increased by 10% - 85% for the mass of the first KK state in the range 500 {approx}> m{sub 1} {approx}> 1500 GeV, a region untested by current direct search and precision measurement constraints. The h {yields} {gamma}{gamma} decay width is decreased by {approx}< 20% in the same mass range. For two or more universal extra dimensions the results are cutoff ...
Polynuclear aromatic sulphur heterocycles (PASHs) were isolated from a coal extract by two-step separation method using silica gel column chromatography and ligand exchanges thin layer chromatography (PdCl{sub 2}/SiO{sub 2}). The subfraction was examined by capillary column gas chromatography with flame ionization detector and flame photometric detector and gas chromatography - mass spectrometry. Identification was accomplished by comparison of chromatographic retention indices and mass spectra of compounds with those reported in the literature. It was found that the principal structures of the sulphur-containing fraction of Guiding coal extract have 3-4 aromatic rings. Dibenzothiophene, C{sub 1} - C{sub 3} alkylated dibenzothiophenes, benzonaphthothiophene and its alkylated derivatives were the main compounds. Only a few other polynuclear sulfur heterocycles were detected. No benzothiophene and its derivatives were ...
Donnan dialysis with ion-exchange membranes was studied under various kinds of experimental conditions using ions of different valences. The diffusion coefficients (D{sub d}) of various kinds of ions in the ion-exchange membrane were obtained by curve fitting an equation derived from the mass balance to three kinds of Donnan dialytic experiments. It was found that the value of D{sub d}/D{sub s} using D{sub d} of monovalent ions in Donnan dialysis with a set of monovalent feed ions and bivalent driving ions was 1/175, where D{sub s} represents a diffusion coefficient in solution. D{sub s} was calculated from the Nernst-Einstein equation substituted by the ionic conductance of ions at infinite dilution in water. Using D{sub d} of bivalent ions in Donnan dialysis with the same set led to a D{sub d}/D{sub s} value of 1/438. Moreover, using D{sub d} in Donnan dialysis with the same set, the value of D{sub d}/D{sub e} was kept ...
Two-phase flow patterns and frictional pressure gradients in flow in small, rectangular channels are being studies as part of a larger research program addressing phase-change heat transfer of pure refrigerants and refrigerant mixtures in plate-fin heat exchangers. Small rectangular flow channels were selected as representative of plain fin geometries. The particular channel reported herein has dimensions of 19.05 {times} 3.18 mm. Adiabatic flows of air/water mixtures, with the flow channel horizontal and the channel exit at near-atmospheric conditions, were utilized in the experiments. Analysis and interpretation of the pressure data relative to observed flow pattern transitions led to an objective method for determining the plug/bubble-to-slug flow transition. This method, together with visual observations, supplemented with photographic data, was used to develop a flow pattern man. A comparison of existing flow pattern maps for circular pipes, capillary tubes, ...
Nanocrystalline zeolites with discrete crystal sizes of less than 100 nm have different properties relative to zeolites with larger crystal sizes. Nanocrystalline zeolites have improved mass transfer properties and very large internal and external surface areas that can be exploited for many different applications. The additional external surface active sites and the improved mass transfer properties of nanocrystalline zeolites offer significant advantages for selective catalytic reduction (SCR) catalysis with ammonia as a reductant in coal-fired power plants relative to current zeolite based SCR catalysts. Nanocrystalline NaY was synthesized with a crystal size of 15-20 nm and was thoroughly characterized using x-ray diffraction, electron paramagnetic resonance spectroscopy, nitrogen adsorption isotherms and Fourier Transform Infrared (FT-IR) spectroscopy. Copper ions were exchanged into nanocrystalline NaY to increase the ...
The anodic reaction kinetics and interfacial mass transport of a direct polymer electrolyte membrane formic acid fuel cell have been investigated in an all solid-state electrochemical cell using a highly active nanostructured palladium-gold alloy microelectrode as an in situ probe. Well-defined 'S-shaped' steady-state cyclic voltammograms exhibiting current-rising region at lower overpotentials and limiting current region at higher overpotentials have been first obtained for the electrochemical oxidation of formic acid at varying temperature. The 'S-shaped' steady state polarization curves and chronoamperometric curves enable convenient measurements of the anodic reaction kinetics and interfacial mass transport of formic acid under real polymer electrolyte membrane conditions. It is encouragingly found that formic acid can be directly oxidized to CO2 with the first electron transfer being the likely rate-determining step and the formation of ...
... Reduce partner costs, save time, and overcome delays in data transmission. Data Exchanges States are currently submitting data to each other and to the EPA in the exchanges listed below. Data Exchanges are typically referred to by their acronyms, which are listed below. To find out more about EPA data exchanges, please follow the links to EPA Web sites. AQS - Air Quality Sub-system (...
The extent of exchange rate pass-through has been playing an increasingly pivotal role in the transmission of exchange rate shocks and adequate policy responses. We develop a model of exchange rate pass-through that allows the stochastic process of exchange rate to include the lagged values of the velocity of money. We show that the likelihood and extent of pass-through is sensitive to the lagged response.
In this paper, we describe our vectorized and parallelized adaptive mesh refinement (AMR) N-body code with shared time steps, and report its performance on a Fujitsu VPP5000 vector-parallel supercomputer. Our AMR N-body code puts hierarchical meshes recursively where higher resolution is required and the time step of all particles are the same. The parts which are the most difficult to vectorize are loops that access the mesh data and particle data. We vectorized such parts by changing the loop structure, so that the innermost loop steps through the cells instead of the particles in each cell, in other words, by changing the loop order from the depth-first order to the breadth-first order. Mass assignment is also vectorizable using this loop order exchange and splitting the loop into $2^{N_{dim}}$ loops, if the cloud-in-cell scheme is adopted. Here, $N_{dim}$ is the number of dimension. These vectorization schemes which eliminate the ...
This paper proposes a model to explain tritium release behavior of an irradiated Li_4SiO_4 sample made by Forschungszentrum Karlsruhe. The release curves were obtained in a series of experiments carried out using out-pile temperature programmed desorption techniques in the Kyoto University Reactor (KUR). Tritium release curves obtained for different purge gas compositions (N_2, N_2 + H_2, N_2 + H_2O) were compared for selection of suitable conditions to determine the apparent diffusivity of tritium in a crystal grain of Li_4SiO_4.In the model formation, some mass transfer steps in the bulk of the crystal grain and those on the surface of the grain were taken into account, which were diffusion of tritium in the grain, adsorption and desorption of water on the surface of the grain, two types of isotope exchange reactions, and water formation reaction by the addition of hydrogen to the purge gas.Diffusivities of tritium in the crystal grain of ...
The improvement of the ecological conditions at waste storing reservoirs is an important task of the restoration activity at Production Association (PA) ``Mayak`` (South Urals). The radionuclides mostly {sup 90}Sr, {sup 137}Cs, and chemical pollutants deposited in the reservoir water and in the bottom sediment are very dangerous sources for the contamination of Techa River below the reservoirs and the contamination of groundwater in the surrounding formations. The spreading of radioactive contaminants has both hydrogeological and the chemical features. The thermodynamic approach used to account for physical-chemical interactions between water and the bed rocks based on Gibbs free energy minimization of multicomponent system (H-O-Ca-Mg-K-Na-S-Cl-C-Sr) permitted the authors to calculate the corresponding ionic and complex species existing in the solutions, and to characterize the processes of precipitation and dissolution. The model takes into account the input and output surface and ...
"7Be produced by the interaction of cosmic rays with oxygen and nitrogen, predominantly in the stratosphere, has been used to identify and measure stratospheric ozone at the ground level. Simultaneous measurements at Whiteface Mountain, New York, in July 1975 show that the maximum "7Be concentrations are accompanied by increased ozone concentrations. Peaks in "7Be concentrations occurred on July 5-6, 11-12, 16-17, 23, and 27. Ozone peaks were observed on July 7-9, 11, 18, 24, and 27. Isentropic trajectory calculations also showed that the trajectories reaching Whiteface Mountain on July 11-12, 15-16, 23, and 27 had stratospheric origin. One-day delay in ozone peaks on July 7-9, 18, and 24 is attributed to increased tropospheric ozone production. The observed relationship between "7Be and ozone is used to deduce an upper limit of 37 ppb stratospheric ozone at Whiteface Mountain during July 1975. Thus, even during midsummer months, when stratospheric-tropospheric ...
An experimental campaign, aiming to investigate the perturbation effects induced by fixed obstacles on turbulence measurements in airflows at the air-sea interface, was carried out at the marine platform of the Italian Navy, located in the harbour of La Spezia (North Ligurian Sea, Italy) on 28., 29., and 30. June 1994. This study was prompted by the ever-growing interest in more reliable estimates of energy, mass, and momentum exchanges between water surfaces and atmosphere, whose measurements are severely limited by the geometrical constraints of floating or fixed platforms where they are installed. Two types of meteorological instruments have been used: fast response (20 and 21 Hz) ultrasonic anemometers and fluxmeters to measure turbulent momentum, sensible, and latent heat fluxes and slow-response sensors (less than 4 Hz and sampled at a rate of 10{sup 2} Hz) to measure average wind and temperature vertical profiles in the perturbed ...
This paper presents the new thermal hydraulic models describing the hydrodynamics of the solid fuel/steel chunks during an LMFBR hypothetical core-disruptive accident. These models, which account for two-way coupling between the solid and fluid phases, describe the mass, momentum, and energy exchanges which occur when the chunks are present at any axial location. They have been incorporated in LEVITATE, a code for the analysis of fuel and cladding dynamics under Loss-of-Flow (LOF) conditions. Their influence on fuel motion is presented in the context of the L6 TREAT experiment analysis. It is shown that the overall hydrodynamic behavior of the molten fuel and solid-fuel chunks is dependent on both the size of the chunks and the power level. At low and intermediate power levels the fuel motion is more dispersive when small chunks, rather than large ones, are present. At high power levels the situation is reversed. These effects are explained in ...
Scaling criteria for a natural-circulation loop are examined. The present state of knowledge of scaling to obtain similarity during single- and two-phase flow conditions in a closed loop are reviewed, and an alternative development of two-phase similarity parameters is presented. The loop scaling criteria are the results of analyses in which flow from one component to another is considered. In this work, boundary conditions for the closed loop are developed to obtain scaling criteria for leak flow, injection flow, and heat loss to ambient. The leak scaling criteria are specialized for modeling approaches using prototypic fluid at prototypic or reduced pressures. The derived scaling parameters are examined for their application to two existing scaled test facilities: the Multi-Loop Integral System Test (MIST) facility at Babcock and Wilcox, and the UMCP 2 x 4 facility at the University of Maryland College Park. The heat loss similarity analysis is performed in conjunction with ...
Air flow and the buoyancy-driven flow through a building`s horizontal openings was discussed. Horizontal openings occur in staircases, stairwells, ventilation shafts and chimneys. Mass and energy transfer through them have important implications regarding energy saving, thermal comfort, control of contaminants and micro-organisms and spread of fire and smoke. The analysis of the buoyancy-driven flow was attained using computational fluid dynamics (CFD). Use was made of the CFD code FLUENT which integrated the Navier-Stokes equations by a time-dependent, finite volume method. Good agreement was achieved between predicted and experimental measurements of flow rate. Results showed that flow patterns in horizontal openings were transient and unstable. The air exchange through the openings occurred in intermittent pulses. The flow rate through the opening increased with the temperature difference between zones in buildings and the size of the ...
A pretreatment flowsheet was tested for separating key radionuclide components from the sludge stored in one of the high level waste tanks (B-110) at the Hanford Site; this sludge resulted primarily from the bismuth phosphate process, which was one of the three major plutonium separation processes used at Handford. This test involved (1) washing with water, (2) caustic leaching, (3) acid dissolution, (4) separation of transuranic elements (TRUs) by extraction with octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide(CMPO), (5) separation of Sr by extraction with di-t-butylcyclohexano-18-crown-6, (6) separation of Cs from the acid-dissolved sludge solution by treatment with ammonium molybdophosphate (AMP), and (7) separation of Cs from the sludge wash and caustic leach solutions by ion exchange using a phenol-formaldehyde resin (CS-100). The results of the radionuclide separation steps indicated that the proposed flowsheet is a viable approach to pretreating ...
A calculation model was developed for the analysis of thermal and hydraulic processes in the PGV-1000 horizontal steam generator. The model makes it possible to examine the hydraulics of the primary medium, i.e., the distribution of flow velocities and mass flows in the exchanger tube system and hydraulic losses of the primary medium in the steam generator during its flow between the two connecting sites to the main circulation pipeline, spatial distribution of heat fluxes between the primary and secondary sides of the steam generator and the total transmitted thermal power, pressure on the secondary side of the generator, natural circulation of the working medium on the secondary side, and the mean circulation number, spatial distribution of the volume fraction of the steam component in the intertubular space, effect of the perforated sheet on the thermo-hydraulic processes in the steam generator, redistribution of the steam component in the ...
A new analysis is presented which links real volume fractions, relaxation rates, and intracompartmental exchange rates directly with apparent volume fractions and relaxation rates obtained from biexponential...Full Text Available
The chloromethylation reaction of an asphaltite and styrene graft copolymer followed by the amination of the chloromethylated products was optimized. New strongly basic anion exchangers with an exchange capacity of 2.5 mg-equiv/g and a mechanical strength of 93% were prepared.
A compact heat exchanger pedestal array for augmenting heat transfer in a machine is disclosed. The compact heat exchanger pedestal array includes a wall having first and second surfaces. The first surface faces a heated flow path and the second surface p...
...standards and implementation specifications for exchanging electronic health information. 170.205 Section 170.205 Public Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES HEALTH INFORMATION TECHNOLOGY HEALTH INFORMATION TECHNOLOGY...
In the present paper, experimental study of forced convection boiling were performed to investigate the post-CHF characteristics of a vertical annular channel with one heated rod and four spacer grids for new refrigerant R-134a. The experiments were conducted under outlet pressure of 11.6, 13, 16 and 20 bar, mass fluxes of 100-600 kg/m{sup 2}s, and inlet temperatures of 25-51 .deg. C. The parametric trend of the post-CHF data was well consistent with previous studies. The two phase flow regime in tube flow occurring downstream of the CHF has been called post-CHF, dispersed flow, liquid-deficient flow, mist flow and film boiling. This regime is characterized by a continuous vapor phase with discrete liquid drops and a non-wetted heated surface. This regime has a considerable importance in the areas of light water reactor(LWR) accident analysis and other film boiling applications. The post-CHF region occurs by design in heat exchangers operating ...
In the present paper, experimental study of forced convection boiling were performed to investigate the post-CHF characteristics of a vertical annular channel with one heated rod and four spacer grids for new refrigerant R-134a. The experiments were conducted under outlet pressure of 11.6, 13, 16 and 20 bar, mass fluxes of 100-600 kg/m2s, and inlet temperatures of 25-51 .deg. C. The parametric trend of the post-CHF data was well consistent with previous studies. The two phase flow regime in tube flow occurring downstream of the CHF has been called post-CHF, dispersed flow, liquid-deficient flow, mist flow and film boiling. This regime is characterized by a continuous vapor phase with discrete liquid drops and a non-wetted heated surface. This regime has a considerable importance in the areas of light water reactor(LWR) accident analysis and other film boiling applications. The post-CHF region occurs by design in heat exchangers operating in the ...
Isotherms have been measured for H(D){sub 2}(g) solution in crystalline Pd{sub 9}Si{sub 2} in the temperature range from 235 to 373 K. The solubilities are significant, e.g., at 1.0 MPa (298 K), (H/Pd) = 0.052 or Pd{sub 9}Si{sub 2}H{sub 0.47}, however, there is no indication of hydride phase formation even down to 235 K at 1.0 MPa. The thermodynamic values for hydrogen solutions at infinite dilution of hydrogen are {Delta}H{degrees}{sub H}= -11.9 kJ/mole {1/2}H{sub 2} and {Delta}S{degrees}{sub H} = -50 J/K mole {1/2}H{sub 2}. The former is more negative than for Pd-H{sub 2} and the latter is somewhat more positive; but generally the values are not that different from Pd-H{sub 2}. The isotope effect is similar to that found for Pd-H(D){sub 2}.
Although clinic environments are a primary location for exchanging information with clinicians, patients experience these spaces as harsh environments to access, use, exchange, and manage information....Full Text Available
The oxygen production of a photosynthetic gas exchanger containing Chlorella pyrenoidosa (1% packed cell volume) was measured when various concentrations of carbon dioxide were present...Full Text Available
The European Union (EU) market integration is leading to increasingly monopolistic electricity market infrastructures, which has opened a debate on the regulation of these so-called power exchanges. In this paper, we start by stating that there are two types of power exchanges in Europe, i.e. 'merchant' and 'cost-of-service regulated' power exchanges. We then discuss how regulation can be used to better align their incentives with the main power exchange tasks. We conclude that adopting the cost-of-service regulated model for all power exchanges in Europe could be counterproductive in the current context, but that regulation can help ensure that the benefits of the EU market integration materialize. Promising regulatory actions include tempering the reinforced market power of power exchanges, and quality-of-service regulation for the ongoing cooperation among ...
The presented paper describes the formulation of the fractional mass balances which are used to calculate the concentration and size distribution of char in the balance cells of a circulating fluidized bed boiler. In case of using the shrinking core model additionally the distribution of conversion of the char particles is calculated. Basically two reaction models (a shrinking particle and a shrinking core model) are available to describe the combustion process. The model considers all essential physico/chemical phenomena (primary fragmentation, attrition, mass transfer to gas phase) which have to be taken into account for the description of the combustion process. The model is part of an overall simulation program for circulating fluidized bed boilers. This engineering simulator has been developed to return the main performance parameters of such systems like temperature along the furnace height, size distribution of balanced solid components, ...
A series of first principles molecular dynamics and Monte Carlo simulations were carried out for liquid water to assess the validity and reproducibility of different sampling approaches. These simulations include Car-Parrinello molecular dynamics simulations using the program CPMD with different values of the fictitious electron mass in the microcanonical and canonical ensembles, Born-Oppenheimer molecular dynamics using the programs CPMD and CP2K in the microcanonical ensemble, and Metropolis Monte Carlo using CP2K in the canonical ensemble. With the exception of one simulation for 128 water molecules, all other simulations were carried out for systems consisting of 64 molecules. It is found that the structural and thermodynamic properties of these simulations are in excellent agreement with each other as long as adiabatic sampling is maintained in the Car-Parrinello molecular dynamics simulations either by choosing a sufficiently small fictitious ...
This paper deals with construction types of high temperature heat exchangers, their circulation loops and temperature differences. Most attention is given to gas dynamics, convective heat transfer, convection and radiant heat transfer interaction in high temperature heat exchangers. The ways of heat transfer augmentation and efficient heat exchanger construction are discussed.
This paper shows that a well designed transport system has an embedded exchange value by serving as a market for potential exchange between consumers. Under suitable conditions, one can improve the welfare of consumers in the system simply by allowing some exchange of goods between consumers during transportation without incurring additional transportation costs. We propose an explicit valuation formula to measure this exchange value for a given compatible transport system. This value is always nonnegative and bounded from above. Criteria based on transport structures, preferences and prices are provided to determine the existence of a positive exchange value. Finally, we study a new optimal transport problem with an objective taking into account of both transportation cost and exchange value.
The patent describes a method for repairing leakage-causing cracks and fissures in a cryogenic heat exchanger. It comprises: reducing the interior pressure of the heat exchanger to a level which does not exceed the external pressure upon the hear exchanger while maintaining the temperature of the heat exchanger at a low level relative to the ambient external temperature; applying a curable liquid filler composition to the surface of the heat exchanger proximal the leakage site for seepage into the cracks and fissures located at the leakage. The composition upon a relatively short period of cure at low temperature forming a solid material which fills the cracks and fissures; curing the filler composition; and, applying a sealant composition to the surface of the heat exchanger at the filled leakage site. The sealant composition having long-term sealing ...
A method is described of controlling an anodic protection system in a heat exchanger comprising: (a) installing at least one cathode within the heat exchanger, at least one cathode being aligned with the longitudinal axis of the heat exchanger and extending substantially along the length of the heat exchanger; (b) installing a first reference electrode within and at one end of the heat exchanger, the first reference electrode having a first controller having a set point for control and a power supply having an output creating an electrical potential between at least one cathode and the heat exchanger; (c) measuring the electrical potential of the heat exchanger with the first reference electrode; (d) operating the first controller in response to measurements made by the first reference electrode to change the output of the power supply; (e) ...
This document reports the results of testing of spent ion exchange media pretreatment technologies. Emphasis of the testing activities has been on screening pretreatment technologies, such as drying and emulsification, which are compatible with vitrification, cementation, and incineration. Ion exchange media tested for cementation and incineration pretreatment technologies were typical organic ion exchange resins and inorganic zeolites. The ion exchange medium tested for vitrification pretreatment technologies was inorganic zeolite. The results of testing activities are discussed in detail in this report.
We present evidence for the creation of an exchange spring in an antiferromagnet due to exchange coupling to a ferromagnet. X-ray magnetic linear dichroism spectroscopy on single crystal Co/NiO(001) shows that a partial domain wall is wound up at the surface of the antiferromagnet when the adjacent ferromagnet is rotated by a magnetic field. We determine the interface exchange stiffness and the antiferromagnetic domain wall energy from the field dependence of the direction of the antiferromagnetic axis, the antiferromagnetic pendant to a ferromagnetic hysteresis loop. The existence of a planar antiferromagnetic domain wall, proven by our measurement, is a key assumption of most exchange bias models.
The thermal-hydraulic performance in periodic frosting conditions is experimentally studied for the parallel-flow parallel-fin heat exchanger, henceforth referred to as a PF{sup 2} heat exchanger, a new style of heat exchanger that uses louvered bent fins on flat tubes to enhance water drainage when the flat tubes are horizontal. Typically, it takes a few frosting/defrosting cycles to come to repeatable conditions. The criterion for the initiation of defrost and a sufficiently long defrost period are determined for the test PF{sup 2} heat exchanger and test condition. The effects of blower operation on the pressure drop, frost accumulation, water retention, and capacity in time are compared under the conditions of 15 sequential frosting cycles. Pressure drop across the heat exchanger and overall heat transfer coefficient are quantified under frost conditions as functions of the air ...
The synthetic process of polyethylene cation exchange capillary via radiation grafting polystyrene by simultaneous irradiation with "6"0Co #gamma#-ray source and sulfonation with concentrated H_2SO_4 was studied. The effects of dose, dose rate, monomer concentration, solvents, temperature and crosslinking agents on the graft copolymerization of styrene with polyethylene capillary were illustrated. The relationship between the radiation grafting conditions and the properties of ion-exchange capillary were examined. A polyethylene cation exchange capillary with I.D. 0.8 mm, length 20 m, exchange capacity 0.7 Meq/g 60% capacity in 10 s (flow rate 20 ml/min) was prepared. No significant loss of copacity was found from this ion-exchange capillary after 200 adsorption/regeneration cycles.
For terrestrial animals and plants, a fundamental cost of living is water vapor lost to the atmosphere during exchange of metabolic gases. Here, by bringing together previously developed models for...Full Text Available
Cytosol proteins prepared from castor bean endosperm (4-day-old) seedlings stimulate the exchange of [3H]phosphatidylethanolamine between liposomes and mitochondria. The acceleration of the...Full Text Available
Plasma exchange (PE) is currently being used to treat a variety of disorders involving immune complexes, such as polyarteritis nodosa. This procedure removes endogenous toxic components that accumulate...Full Text Available
Background:The cardiac sodium–calcium exchanger (NCX1) is a key sarcolemmal protein for the maintenance of calcium homeostasis in the heart. Since heart failure...Full Text Available
Experience has shown that a list of tips provides designers and engineers with an effective guide in their areas of duties and concern. This list contains new and rare information on heat exchangers and heat recovery systems. The information presented can be used effectively with personal computers and pocket calculators and also conveniently translated into computer programs and nomographs.
The continued evolution of bacterial pathogens has major implications for both human and animal disease, but the exchange of genetic material between host-restricted pathogens is rarely considered....Full Text Available
We analyse the relation between the exchange algebra and the separation of the chiralities in classical Toda field theory. We show that there exists a conformally covariant Bloch wave basis such that the two chiralities commute. In terms of this basis we then reconstruct the periodic and local solution of Toda field theory. (orig.).
Severance of the ureter beyond the renal papilla causes a fall in urinary osmolality, which suggests that exchange of water or solute between urine and renal parenchyma normally occurs in the intact...Full Text Available
The effects of Escherichia coli endotoxin on lung mechanics, hemodynamics, gas exchange, and lung fluid and solute exchange were studied in 12 chronically instrumented unanesthetized sheep. A possible...Full Text Available
The flow distribution through a plate-fin heat exchanger is studied by using a computational fluid dynamics (CFD) code, FLUENT. The flow distribution through any heat exchanger affects its performance. In designing a heat exchanger, it is assumed that the fluid is uniformly distributed through the heat exchanger core. In practice, however, it is impossible to distribute fluid uniformly, because of an improper inlet configuration, imperfect design, and a complex heat transfer process. The CFD simulation of the flow distribution in the header of a conventional plate-fin heat exchanger is presented. It is found that the flow maldistribution is very serious in the y-direction of the header. A modified header is proposed and simulated using CFD. The modified header configuration has a more uniform flow distribution than the conventional header configuration. Hence, the efficiency of the ...
An anion-exchange column technique for extraction of antibiotics from serum proteins has been developed for use in the assay of cephapirin, cefotaxime, and cefoxitin by high-pressure liquid chromatography....Full Text Available
Compact heat exchangers are being increasingly considered for condensation applications in the process, cryogenic, aerospace, power and refrigeration industries. In this paper, different configurations available for condensation applications are analyzed and the current state-of-the-knowledge for the design of compact condensers is evaluated. The key technical issues for the design and development of compact heat exchangers for condensation applications are analyzed and major advantages are identified. The experimental data and performance prediction methods reported in the literature are analyzed to evaluate the present design capabilities for different compact heat-exchanger configurations. The design flexibility is evaluated for the development of new condensation applications, including integration with other process equipment.
Separation of lithium isotopes was investigated by chemical ion exchange with a hydrous manganese(IV) oxide ion exchanger using an elution chromatography. The capacity of manganese(IV) oxide ion exchanger was 0.5 meq/g. The heavier lithium isotope was enriched in the solution phase, while the lighter isotope was enriched in the ion exchanger phase. The separation factor was determined according to the method of Glueckauf from the elution curve and isotopic assays. The separation factor of {sup 6}Li{sup +} -{sup 7}Li{sup +} isotope pair fractionation was 1.018.
Four trypsin inhibitor homologs, the first known from Dendroaspis angusticeps venom, were characterized using a combination of gel filtration, cation exchange, reverse-phase liquid chromatography, Edman degradation and mass spectrometry. The four toxins comprise two 57 residue and two 59 residue isoforms. The long toxins possess a Lys-Gln N-terminal extension lacked by the short toxins. The only other structural difference is an Arg/His replacement at position 55. The long Arg55 variant is identical to trypsin inhibitor E from the venom of Dendroaspis polylepis. The name epsilon-dendrotoxin is suggested so as to follow the nomenclature of Benishin, C.G., Sorensen, R.G., Brown, W.E., Krueger, B.K., Blaustein, M.P., 1988. Four polypeptide components of green mamba venom selectively block certain potassium channels in rat brain synaptosomes. Mol. Pharmacol. 34, 152-159. Among snake venom protease inhibitors, the epsilon-dendrotoxins are ...
A numeric method for predicting mineral ash deposition in coal dust furnaces is presented which is based on a bidirectional working time coupling of thermodynamic calculation routines (ChemApp{sup TM}) with the commercial CFD code FLUENT{sup TM}. The deposition characteristics of particles and wall surfaces is assessed on the basis of evaluations of flow simulation parameters and results of thermodynamic calculations for the mineral matter contained in the fuel particles, taking into account the complete energy, momentum and massexchange history of the ash and the mineral conversion. The models enables calculations of the gaseous release of mineral components (e.g. alkaline substances and chlorine) from ash during combustion and its distribution inside a combustion chamber. The method and model are validated using experimental data. (orig.) [German] In der vorliegenden Arbeit wird ein numerisches Verfahren beschrieben, mit dem die ...
The isostructural #gamma#-#alpha# phase transition of Ce which occurs at 8 kbar has been studied by means of fully self-consistent (non-muffin-tin potential) linearized-augmented-plane-wave energy band calculations carried out for five different values of the lattice constant. In contradiction to the 4f electron promotional model of the transition, the results yield essentially one 4f electron to be occupied in each phase but with the 4f wave function somewhat less localized, and therefore more bandlike, in the ''collapsed'' #alpha# phase. A singly occupied 4f state is shown to be consistent with the available experimental data. These results strongly support the picture of a 4f localized bold-arrow-left-right itinerant transition at the #gamma#-#alpha# transition and conflict with the promotional model in which some fraction of 4f electrons are transferred to the sd conduction bands. The weaker bonding of the 4f electrons, compared to that of the 6s-5d valence electrons, accounts for ...
From the dried fruiting bodies of the mushroom Armillaria luteo-virens, a dimeric lectin with a molecular mass of 29.4 kDa has been isolated. The purification procedure involved (NH{sub 4}){sub 2}SO{sub 4} precipitation, ion exchange chromatography on DEAE-cellulose, CM-cellulose, and Q-Sepharose, and gel filtration by fast protein liquid chromatography on Superdex 75. The hemagglutinating activity of the lectin could not be inhibited by simple sugars but was inhibited by the polysaccharide inulin. The activity was stable up to 70 {sup o}C but was acid- and alkali-labile. Salts including FeCl{sub 3}, AlCl{sub 3}, and ZnCl{sub 2} inhibited the activity whereas MgCl{sub 2}, MnCl{sub 2}, and CaCl{sub 2} did not. The lectin stimulated mitogenic response of mouse splenocytes with the maximal response achieved by 1 {mu}M lectin. Proliferation of tumor cells including MBL2 cells, HeLa cells, and L1210 cells was inhibited by the lectin with an IC{sub ...
The physics and technology of this new Cerenkov detector are discussed, including materials studies, construction techniques, and resolution measurements. Sources of resolution error are individually identified and measured where possible. The results of all studied indicate that the measurement resolution is understood. This work has led to the adoption of a large scale ring imaging detector as part of a new high energy physics spectrometer, the SLD, at the Stanford Linear Accelerator Center. Results from an amplitude analysis of strange meson final states in K/sup /minus//p ..-->.. /ovr K/sub 0//..pi../sup /minus//p interactions are presented. The data derive from a 4 event/nb exposure of the LASS (large Aperture Superconducting Solenoid) spectrometer to an 11 GeV/c K/sup /minus// beam. The data sample consists of /approximately/100,000 vents distributed over the Dalitz plot of the channel. The process is observed to be dominated by the production and decay of natural spin-parity ...
Small circular and noncircular channels are representative of flow passages in compact evaporators and condensers. This paper describes results of an experimental study on heat transfer to the flow boiling of refrigerant- 12 in a small circular tube of diameter = 2.46 mm. The objective of the study was to assess the effect of channel size on the heat transfer coefficient and to obtain additional insights relative to the heat transfer mechanisms. The flow channel was made of brass and had an overall length of 0.9 m. The channel wall was electrically heated, and temperatures were measured on the channel wall and in the bulk fluid stream. Voltage taps were located at the same axial locations as the stream thermocouples to allow testing over an exit quality range of 0.21 to 0.94 and a large range of mass flux (63 to 832 kg/m{sup 2}s) and heat flux (2.5 to 59 kW/m{sup 2}). Saturation pressure was nearly constant, averaging 0.82 MPa for most of the testing; a few test ...
During the last two decades, the demand for higher heat transfers in the heat exchangers has kept increasing. These high heat transfer rates can be obtained by using two-phase flows, or heat transfer augmented surfaces, or in some cases, both. Thus, the boiling flows and the associated two-phase flow instabilities have been studied by many investigators. Most of the work in boiling flows has been concentrated on single channel upflow systems or on parallel channel systems with plain heat transfer surfaces. The boiling flow instabilities in multi-channel systems should be covered to a greater extent, studying the effects of various parameters, such as inlet and outlet restriction, mass flow rates, the property variations, heat transfer coefficients, equal and unequal heat inputs on the stability. Also, the mathematical modeling needs to be developed for the parallel channel system to take into account the above mentioned variables. The research ...
Using the PMR method the interaction of zirconium and hafnium tetrachlorides with tri.tet.butylphenyl ester of 1,2- naphthoquinonediazide (2)-5-sulfonic acid is studied. The formation of MCl/sub 4/xNQD complexes is established, the equilibrium constants and thermodynamic parameters of complexing reaction are determined. The presence of rapid ligand exchange, proceeding according to associative mechanism, is detected. The rate constants and activation energies of the exchange reaction are calculated.
Using the PMR method the interaction of zirconium and hafnium tetrachlorides with tri.tet.butylphenyl ester of 1,2- naphthoquinonediazide (2)-5-sulfonic acid is studied. The formation of MCl_4xNQD complexes is established, the equilibrium constants and thermodynamic parameters of complexing reaction are determined. The presence of rapid ligand exchange, proceeding according to associative mechanism, is detected. The rate constants and activation energies of the exchange reaction are calculated.
Classical molecular dynamics simulations are carried out to investigate the salvation shell exchange kinetics of potassium ion in bulk water, chloroform, and carbon tetrachloride. The reactive flux method is used to compute the dissociation rates. The influence of the solvent on the reaction rates and kinetic properties of this exchange process will be discussed. Comparison will be also be made to the prediction of the Grote-Hynes theory.
The behavior of air flows in complex heat exchanger passages is reviewed with a focus on the heat transfer effects of boundary-layer development, turbulence, spanwise and streamwise vortices, and wake management. Each of these flow features is discussed for the plain, wavy, and interrupted passages found in contemporary compact heat exchanger designs. Results from the literature are used to help explain the role of these mechanisms in heat transfer enhancement strategies.
In order to evacuate the residual power in a nuclear reactor, a thermal valve system is presented for the modification of the heat exchange conditions at the pool exchanger level, which avoids the use of mechanical valves on the pipes. The system involves a vessel containing the exchanger, with openings at the upper end of the vessel and means for feeding the fluid at the lower end, and means for controlling the opening width.
The regional impacts of ozone on corn, wheat, soybean, and peanut crops are estimated by using dose-response functions to relate ambient maximum 7 h/d seasonal ozone concentrations to crop productivity data. Linear dose-response functions were developed from open-top field chamber studies. It was assumed that the limited number of cultivars and growing conditions available for the analysis were representative of major agricultural regions. Hourly ozone data were selected to represent rural concentrations and used to calculate maximum 7-h/d average values. Seasonal ozone averages for counties were extrapolated from approximately 300 monitoring sites. Results must be interpreted with knowledge of these assumptions and sources of uncertainty. Impacts are calculated for county units for the conterminous United States with maps showing patterns and tables summarizing the potential magnitude of ozone effects on selected crop yields. The assessment ...
As both computer and mobile phone reach nearly ubiquity in the U.S. market, the slow uptake of mobile video, in contrast to the thriving usage of PC-based video, warrants a deeper understanding of user-oriented factors contributing to the two diffusion paths. Unlike the majority of existing diffusion research practices, the dissertation examines the differences between mobile and PC video diffusion patterns through the lenses of user-oriented influences in the user-technology relationship. Built upon the established adoption user group classification, the research is informed by the Uses and Gratification theory, the Social Technical theory, and the Technical Affordance perspective. These synergistic theoretical arguments share the recognition of the role of user in the dynamic, usually socially intertwined user-technology interactions. The key research questions that the dissertation sets out to answer include: Does the importance of quality of viewing experience in adoption ...
A simple method is presented for the separation of lead-203 from copper-backed thallium cyclotron targets. The procedure involves cation-exchange chromatography in hydrochloric acid and hydrochloric acid-acetone mixtures. Further purification involves anion-exchange chromatography in nitric acid-hydrobromic acid mixtures. A cation-exchange column containing 3.0 g of resin can handle as much as 15 g of thallium and 160 mg of copper. An anion-exchange column containing 3.0 g of resin can separate lead from up to 200 mg of thallium and 10 mg of copper. Separations are extremely sharp and less than 0.1 ..mu..g of thallium and less than 0.1 ..mu..g of copper remain in the lead-203 fraction.
A simple method is presented for the separation of lead-203 from copper-backed thallium cyclotron targets. The procedure involves cation-exchange chromatography in hydrochloric acid and hydrochloric acid-acetone mixtures. Further purification involves anion-exchange chromatography in nitric acid-hydrobromic acid mixtures. A cation-exchange column containing 3.0 g of resin can handle as much as 15 g of thallium and 160 mg of copper. An anion-exchange column containing 3.0 g of resin can separate lead from up to 200 mg of thallium and 10 mg of copper. Separations are extremely sharp and less than 0.1 #mu#g of thallium and less than 0.1 #mu#g of copper remain in the lead-203 fraction. (author).
In this study, the use of the weakly basic anion exchange resins of phenol-formaldehyde (Amberlyst A 23), polyacrylate (Amberlite IRA 67) and polystyrene (Lewatit MonoPlus MP 62) matrices for removal of the reactive dye Remazol Black B (RBB) from aqueous solution and wastewater were investigated. RBB sorption on the anion exchangers was a time dependent process. Color reduction percentiles of 75.2, 33.9 and 25.1% in wastewater treatment were found after 216 h of phase contact time with Lewatit MonoPlus MP 62, Amberlyst A 23 and Amberlite IRA 67, respectively. Inorganic salts and anionic surfactant action influenced RBB uptake by the anion exchangers. The amounts of dye retained by the anion exchangers increased with a rise in temperature. The maximum sorption capacities calculated from the...
This paper employs a new approach in order to investigate the underlying relationship between stock markets and exchange rates. Current approaches suggest that the relative equity market performance of two countries is linked to their exchange rate. In contrast, this study proposes an alternative approach where one global variable - global equity market returns - is believed to have an effect on exchange rates, with the relative interest rate level of a currency determining the sign of the relationship. Our empirical findings suggest that exchange rates and global stock market returns are strongly linked. The value of currencies with higher interest rates is positively related with global equity returns, whereas the value of currencies with lower interest rates is negatively related with g...
In this paper, numerical simulation of a concentric tube heat exchanger is presented to determine the convective heat transfer coefficient and friction factor in a smooth tube. Increasing the convective heat transfer coefficient can increase heat transfer rate in a concentric tube heat exchanger from a given tubular surface area. This can be achieved by using heat transfer augmentation devices. This work constitutes the initial phase of the numerical simulation of heat transfer from tubes employing augmentation devices, such as twisted tapes, wire-coil inserts, for heat transfer enhancement. A computational fluid dynamics (CFD) simulation tool was developed with CFX software and the results obtained from the simulations are validated with the empirical correlations for a smooth tube heat exchanger. The difficulties associated with the simulation of a heat exchanger augmented with wire-coil inserts are ...
The performance of spherical Resorcinol-Formaldehyde ion-exchange resin for the removal of cesium from alkaline radioactive waste solutions has been investigated through computer modeling. Cesium adsorption isotherms were obtained by fitting experimental data using a thermodynamic framework. Results show that ion-exchange is an efficient method for cesium removal from highly alkaline radioactive waste solutions. On average, two 1300 liter columns operating in series are able to treat 690,000 liters of waste with an initial cesium concentration of 0.09 mM in 11 days achieving a decontamination factor of over 50,000. The study also tested the sensitivity of ion-exchange column performance to variations in flow rate, temperature and column dimensions. Modeling results can be used to optimize design of the ion exchange system.
The contribution of exchange processes (heavy stripping and substitution) into the amplitude of the 25-30 MeV #alpha#-particle elastic scattering by "1"2C and "4"0Ca nuclei is examined taking into account the distortion of plane waves of initial and finite particles. The eikonal approximation is used for accounting for distortions. The matrix elements of exchange processes are calculated. The results of calculations show that the Wronskian cutoff radii are close to those which have been obtained for calculation of exchange processes in the plane-wave approximation. The moduli of the values defining the contribution of exchange processes to the total S matrix are plotted. Also presented are Argand diagrams and angular distributions for both reactions. It has been established that the account for exchange processes improves the agreement of theoretical curves with the experiment in ...
A research was started aiming at evaluating the possible use of natural zeolites as exchange conditioners to improve and make durable the soil resilience against the adverse effects of the use of anomalous waters for irrigation purposes. This paper deals with a preliminary investigation on the comparative resilience of an Entisol with poor exchange properties and of a Neapolitan yellow tuff (NYT) sample against the adverse features of a dirty municipal sewage (DSW). Results showed that NYT treatment largely and significantly improved the poor soil exchange activity. In particular. NYT exchange sites selectively took up ammonium from DSW. As a consequence, ammonium was trapped, then protected against losses in the environment and, concurrently, exchangeable cations, such as K and Ca, were made free as plant nutrients. The results highlight the possible positive role of zeolitized ...
This chapter consists of some points including an introduction, the basic parts of mass spectroscope device, sample introduction into the inductively coupled plasma, pneumatic nebuliser, ultrasonic nebuliser, dry gas cloud system, laser ablation unit, inductively coupled plasma-ion source, extraction of ions from ion source, mass analysis, quad-polar mass spectrometer, dual assembly mass spectrometer, mass spectrometer by calculation of time of flight, ion interferences and the ability of resolution, ion counter, working conditions of inductively coupled plasma mass spectroscope device, efficiency of ion transportation in an inductively coupled plasma mass spectroscope device and applications of analysis using mass spectroscope of induced plasma including nuclear, industrial, geological, environmental and archaeological ...
A large double-focusing mass spectrometer was used to obtain new values for the masses of Sr/sup 86/, Sr/sup 88/, and Zr/sup 90/. Mass differences calculated from these values are found to be in better agreement with nuclear transmutation information than were previous mass spectroscopically derived values. (auth)
Results are presented of an empirical analysis of the global thermodynamical requirements of the winds in the outer atmospheres of a representative sample of red giant stars of low- and intermediate-mass range. Results indicate that the mass-loss rates in these stars are not strongly dependent on the actual physical processes driving the winds. It is suggested that nonlinear processes act to regulate wind energy fluxes. Possible mechanisms responsible for the chromospheric heating and the mass loss in the low- and intermediate-mass giant stars are discussed. 151 refs.
Atomization of liquid fuel in aircraft engines requires application of airblast atomizers, where the kerosene is supplied into the shear layer between two swirling airstreams. The transfer of this functional principle towards gaseous fuel, as illustrated in Fig. 1, yielded a strong influence of the swirl arrangement of the airflows on flame stability and homogeneity of the fuel/air-mixture. Compared to the co-swirl configuration the flow field of the counter-swirl arrangement exhibits a marked increase of the mass flow recirculated in the internal recirculation zone and a reduction of its length in axial direction. This is attributed to the faster decay of tangential velocity maxima in case of counter-rotating airflows. This generates a stronger positive axial pressure gradient dp/dx, thus enhancing the internal recirculation zone. Analysis of local turbulence quantities yields a restriction of turbulent exchange to smaller radial sections and ...
A theoretical derivation of the intershell mass--core mass relation of Paczynski is attempted. Formulae developed by Sugimoto and Fujimoto are extended to less massive (m/sub c/< or approx. =1) cores.
Three subbituminous coals of different rank demineralized in HCl and HF aqueous solutions were treated with several metal salt aqueous solutions to produce corresponding cation exchanged coals. In this treatment, the demineralized coals were exchanged by cations (K{sup +}, Na{sup +}, Mg{sup 2+}, Ca{sup 2+}, Fe{sup 3+} and Al{sup 3+}), which are known to be the major elements in coal minerals. The relations between the content and the kind of exchanged cations were investigated. For lower rank coals, such as Adaro and Black Thunder coals, almost linear relations between the content of exchanged cations and the decreasing amounts of pyridine soluble yields of the cation exchanged coals based on the values in the respective demineralized coals were found. From the differences of the gradients, it was confirmed that the noncovalent associations such as hydrogen bonds between pyridine ...
The obligations of organisations associated with policy formation and implementation of international mass public health programmes are explored. Lines of responsibility are considered to become unclear...Full Text Available
We discuss first the flavor mixing of the quarks, using the texture zero mass matrices. Then we study a similar model for the mass matrices of the leptons. We are able to relate the mass eigenvalues of the charged leptons and of the neutrinos to the mixing angles and can predict the masses of the neutrinos. We find a normal hierarchy - the masses are 0.004 eV, 0.01 eV and 0.05 eV. The atmospheric mixing angle is given by the mass ratios of the charged leptons and the neutrinos. we find about 40 degrees, consistent with the experiments. The mixing element, connecting the first neutrino wit the electron, is predicted to be 0.05. This prediction can soon be checked by the Daya Bay experiment.
Carbon dioxide is receiving renewed interest as an efficient and environmentally safe refrigerant in a number of applications, including mobile air conditioning and heat pump systems, and hot water heat pumps. Compact heat exchangers for CO{sub 2} systems are designed with small-diameter tubing. The purpose of this study is therefore to provide a better basis for understanding and predicting heat transfer and pressure drop during flow vaporization of CO{sub 2} in microchannels. The ''unusual'' properties of carbon dioxide give heat transfer and two-phase flow characteristics that are very different from those of conventional refrigerants. Examples of these differences are the much higher pressure, the resulting high vapour density, a very low surface tension, and a low liquid viscosity. High pressure and low surface tension has a major effect on nucleate boiling characteristics, and earlier test data have shown a clear dominance ...
The masses of the proton-rich nuclides {sup 85,86,87}Mo and {sup 87}Tc have been measured with the Penning trap mass spectrometer SHIPTRAP at GSI. The measured mass excesses of these nuclei deviate from the values of the Atomic Mass Evaluation 2003 by up to 1.6 MeV, indicating a systematic shift of the mass surface in this region compared to previous measurements. A local mass extrapolation based on the new results has been made for the mass range A=80-95. Measured and extrapolated mass values and the derived separation energies have been compared to theoretical mass models. Taking into account the new mass excess values, rp-process network calculations have been performed. Preliminary results show changes in the final abundances for A=86-92 by up to a factor of 30. Results of ...
The masses of the proton-rich nuclides "8"5","8"6","8"7Mo and "8"7Tc have been measured with the Penning trap mass spectrometer SHIPTRAP at GSI. The measured mass excesses of these nuclei deviate from the values of the Atomic Mass Evaluation 2003 by up to 1.6 MeV, indicating a systematic shift of the mass surface in this region compared to previous measurements. A local mass extrapolation based on the new results has been made for the mass range A=80-95. Measured and extrapolated mass values and the derived separation energies have been compared to theoretical mass models. Taking into account the new mass excess values, rp-process network calculations have been performed. Preliminary results show changes in the final abundances for A=86-92 by up to a factor of 30. Results of ...
The masses of proton rich nuclides in the vicinity of N=Z=43 were measured with the Penning trap mass spectrometer SHIPTRAP at GSI. These nuclei were produced in the fusion-evaporation reaction {sup 36}Ar+{sup 54}Fe at energies of 5.0 and 5.9 MeV/u and separated at the velocity filter SHIP. The data are of astrophysical interest since these nuclei are believed to be a part of the rp and {nu}p process paths. The masses of {sup 85}Mo and {sup 87}Tc were measured for the first time. The masses of another two nuclides, {sup 86,87}Mo, were determined for the first time in a direct mass measurement. For these nuclides the mass excess deviates from values of the 2003 Atomic Mass Evaluation by up to 1.5 MeV, indicating a systematic shift of the mass surface in this region of the nuclear chart. Additionally, the ...
The masses of proton rich nuclides in the vicinity of N=Z=43 were measured with the Penning trap mass spectrometer SHIPTRAP at GSI. These nuclei were produced in the fusion-evaporation reaction "3"6Ar+"5"4Fe at energies of 5.0 and 5.9 MeV/u and separated at the velocity filter SHIP. The data are of astrophysical interest since these nuclei are believed to be a part of the rp and #nu#p process paths. The masses of "8"5Mo and "8"7Tc were measured for the first time. The masses of another two nuclides, "8"6","8"7Mo, were determined for the first time in a direct mass measurement. For these nuclides the mass excess deviates from values of the 2003 Atomic Mass Evaluation by up to 1.5 MeV, indicating a systematic shift of the mass surface in this region of the nuclear chart. Additionally, the masses of ...
In ionic nanocrystals the cationic sub-lattice can be replaced with a different metal ion via a fast, simple, and reversible place-exchange, allowing post-synthetic modification of the composition of the nanocrystal, while preserving its size and shape. Here, we demonstrate for the first time that during such an exchange, the anionic framework of the crystal is preserved. When applied to nanoheterostructures, this phenomenon ensures that compositional interfaces within the heterostructure are conserved throughout the transformation. For instance, a morphology composed of a CdSe nanocrystal embedded in a CdS rod (CdSe/CdS) was exchanged to a PbSe/PbS nanorod via a Cu2Se/Cu2S structure. During every exchange cycle, the seed size and position within the nanorod were preserved, as evident by excitonic features, Z-contrast imaging, and elemental line-scans. Anionic framework conservation extends the domain ...
The leak before break (LBB) concept is difficult to apply to a structure with a thin tube that is immersed in a water environment. A heat exchanger in a nuclear power plant is such a structure. The present paper addresses an application of the LBB concept to a heat exchanger in a nuclear power plant. The minimum leaked coolant amount containing the radioactive material which can activate the radiation detector device installed near the heat exchanger is assumed. The postulated initial flaw size that cannot grow to the critical flaw size within the time period to activate the radiation detector is justified. In this case, the radiation detector can activate the warning signal caused by coolant leakage from initially postulated flaws of the heat exchanger. The nuclear plant can safely shutdown when this occurs. Since the postulated initial flaw size can not grow to the critical flaw size, the structural ...
The refrigerant two-phase flows in a distributor and a simulated plate heat exchanger with a single passage used in a compression-type refrigerator were visualized by real-time neutron radiography. For a distributor, the liquid fraction in the each tube was measured by some image processing method. On the other hand, for a plate heat exchanger, the two-dimensional distribution of void fraction was measured quantitatively by the umbra method. As a result, it was shown that the dynamic behaviors of refrigerant at the inlet of the section strongly affected on the performance, that is, a distribution performance of a distributor and a liquid distribution in a plate heat exchanger. (author)
We studied two-photon exchange for elastic electron-proton scattering at low Q{sup 2}. Compact approximate formulas for the amplitudes were obtained. Numerical calculations were done for Q{sup 2}{<=}0.1 GeV{sup 2} with several realistic form factor parametrizations, yielding similar results. They indicate that the corrections to the magnetic form factor can visibly affect the cross-section and proton radii. For low-Q{sup 2} electron-neutron scattering two-photon exchange corrections were shown to be negligibly small00.
In the course of this year six local exchange offices with alternative heating and hot water plants were started up in Switzerland. They are all of the same building type, designed for not more than 1000 telephone subscribers and for the same architectural conditions. However, the buildings are situated in different areas of the country and are thus subject to different environmental conditions. Solar collectors supplemented by electricity boilers are fitted to two of these objects. Heat pumps are operated in two other exchange offices while the last two are equipped with electric heating devices. For purposes of comparison two new test plants of the same size with oil heating devices are set up.
Vibrational dephasing in condensed phases is studied from both a theoretical and experimental standpoint. A theory is presented which describes the dynamics of motional or exchange processes in weakly perturbed systems. This general formalism, which has been previously used to describe motional narrowing in magnetic resonance, is applied to vibrational spectroscopy. The model treats the case of a high frequency vibration anharmonically coupled to a low-frequency vibration. Intermolecular exchange of low frequency vibrational quanta results in a temperature dependent broadening and frequency shift of the high frequency vibration. Analysis of experimental data by this model yields both the exchange rates and the anharmonic couplings.
The use of finely powdered ion exchange resins improve loading of specific ion exchange materials with better performance but as such these materials are not suitable for column operation. However, by proper selection of ion exchange support medium, it is possible to get better product. The radioactive solution can be treated by suspending this material, stirring and allowing to settle. The present method gives DF in the range of 70 - 80 even after repeated use as compared to DF in the range of 5 to 10 by single conventional chemical treatment process. (author)
An improved hybrid solar/combustion powered receiver of the type having an insulated housing with a front end and a rear end, a heat exchanger positioned adjacent the rear housing end for extracting heat energy out of the receiver, the insulated housing surrounding the heat exchanger and forming a receiver cavity, the housing also including an aperature having an aperture axis, the aperture located in the front housing end for admitting solar radiation to the cavity to impinge upon the heat exchanger, and a plurality of gas burners to provide combustion gases within the receiver.
A cooling system for rejecting waste heat consists of a cooling tower incorporating a plurality of coolant tubes provided with cooling fins and each having a plurality of cooling channels therein, means for directing a heat exchange fluid from the power plant through less than the total number of cooling channels to cool the heat exchange fluid under normal ambient temperature conditions, means for directing water through the remaining cooling channels whenever the ambient temperature rises above the temperature at which dry cooling of the heat exchange fluid is sufficient and means for cooling the water. 5 figs.
Tube failures due to excessive flow-induced vibration must be avoided to assure the reliable performance of heat exchangers. Such components must be thoroughly analysed for vibration at the design stage. Several flow-induced vibration mechanisms are possible. In this paper, particular attention is given to fluidelastic instability of tube bundles subjected to liquid and two-phase cross-flow. The performance of ten operating heat exchanger components is reviewed to validate our recommended vibration analysis guidelines. Both tube failure histories and satisfactory performances are considered. The results show that a fluidelastic instability constant K=3.3 is a reasonable design criterion. (auth).
We discuss elastic electron-deuteron (ed) scattering beyond the Born approximation. The reaction amplitude contains six generalized form factors, but only three linearly independent combinations of them (generalized charge, quadrupole, and magnetic form factors) contribute to the reaction cross section in second-order perturbation theory. We examine the two-photon exchange and find that it includes two types of diagrams, where two virtual photons are interacting with the same nucleon and where the photons are interacting with different nucleons. It is shown that the two-photon-exchange amplitude is strongly connected with the deuteron wave function at short distances.
This paper details the design, construction and testing of a bayonet tube heat exchanger for use in the process industry and potentially as part of an externally fired combined cycle. Detailed analysis of the system has been undertaken, in particular on the tube side. The data is reported in terms of temperature, pressure, heat gain and heat exchanger effectiveness, over a range of Reynolds numbers and shell side mixture ratios. Much of the heat gained by the tubes is in the annular flow of the bayonet tube. Overall the effectiveness of this system could exceed 70%. (Author)
The interaction between N-donor adsorbates such as ammonia and pyridine with Cu(II)-exchanged montmorillonite, beidellite, flourohectorite into smectite clays has been studied by electron spin resonance. Cu(II) cations exchanged into smectites coordinate five ammonia or pyridine molecules in beidellite, four ammonia of pyridine molecules in hydroxyhectorite. Thus, the Cu(II) cations bound to the interior surfaces of these smectite clays constitute strong Lewis acid sites. 26 refs., 7 figs., 1 tab.
Aims: I have analyzed a sample of seven nearby edge-on galaxies observed in the V and K'-band, in order to infer the properties of the dust distribution. Methods: A radiative transfer model, including scattering, have been used to decompose each image into a stellar disk, a bulge, and a dust disk. The parameters describing the distributions have been obtained through standard X^2 minimization techniques. Results: The dust disks fitted to the V-band images are consistent with previous work in literature: the radial scalelength of dust is larger than that for stars (h_d/h_s ~ 1.5); the dust disk has a smaller vertical scalelength than the stellar (z_d/z_s ~ 1/3); the dust disk is almost transparent when seen face-on (central, face-on, optical depth tau_0 =0.5-1.5). Faster radiative transfer models which neglect scattering can produce equivalent fits, with changes in the derived parameters within the accuracy of full fits including scattering. In the K'-band, no trace ...
We present a model of inflation in a supergravity framework in the Einstein frame where the Higgs field of the next to minimal supersymmetric standard model (NMSSM) plays the role of the inflaton. Previous attempts which assumed non-minimal coupling to gravity failed due to a tachyonic instability of the singlet field during inflation. A canonical K\\"{a}hler potential with \\textit{minimal coupling} to gravity can resolve the tachyonic instability but runs into the $\\eta$-problem. We suggest a model which is free of the $\\eta$-problem due to an additional coupling in the K\\"{a}hler potential which is allowed by the Standard Model gauge group. This induces directions in the potential which we call K-flat. For a certain value of the new coupling in the (N)MSSM, the K\\"{a}hler potential is special, because it can be associated with a certain shift symmetry for the Higgs doublets, a generalization of the shift symmetry for singlets in earlier models. We find that K-flat direction has ...
High surface ozone concentration is increasingly being recognized as a factor that negatively affects crop yields in Asia. However, little progress has been made in developing ozone-tolerant genotypes of rice-Asias major staple crop. This study aimed to identify possible tolerance mechanisms by characterizing two quantitative trait loci (QTLs) that were previously shown to influence visible leaf symptoms under ozone exposure (120 nl l-1, 7 hd-1, 13 d). Two chromosome segment substitution lines (SL15 and SL41) that carried introgressions of the QTLs OzT3 and OzT9, respectively, were exposed to ozone at 120 nl l-1 along with their parent Nipponbare. In accordance with the expected QTL effect, SL15 showed stronger visible symptoms of ozone damage than Nipponbare, whereas SL41 had fewer sympt...
Technologies producing high power negative ion beams have been highly developed in these years at JAERI for use in neutral beam injectors for heating the thermonuclear fusion plasmas. At present, it is possible to produce multi-ampere H-/D- ion beams quasi-continuously at energies more than a few hundred keV with a good beam optics of beamlet divergence of a few milli-radian. Based on these technologies, two R and D projects have been initiated; one is to develop a 22A/500keV/10s D- ion source for the neutral beam injector for JT-60U, and the other is to develop a 1A/1MeV/60s H- ion source to demonstrate high current negative ion acceleration up to the energy of 1MeV, the energy required for the neutral beam injector for International Thermonuclear Experimental Reactor (ITER). (author).
In this paper, for a given sequentially Yoneda-complete T_1 quasi-metric space (X,d), the domain theoretic models of the hyperspace K_0(X) of nonempty compact subsets of (X,d) are studied. To this end, the $\\omega$-Plotkin domain of the space of formal balls BX, denoted by CBX is considered. This domain is given as the chain completion of the set of all finite subsets of BX with respect to the Egli-Milner relation. Further, a map $\\phi:K_0(X)\\rightarrow CBX$ is established and proved that it is an embedding whenever K_0(X) is equipped with the Vietoris topology and respectively CBX with the Scott topology. Moreover, if any compact subset of (X,d) is d^{-1}-precompact, \\phi is an embedding with respect to the topology of Hausdorff quasi-metric H_d on K_0(X). Therefore, it is concluded that (CBX,\\sqsubseteq,\\phi) is an $\\omega$-computational model for the hyperspace K_0(X) endowed with the Vietoris and respectively the Hausdorff topology. Next, an algebraic ...
It is expected that the progressive increase of tropospheric trace gases such as CO{sub 2} and O{sub 3} will have a significant impact on agricultural production. The single and combined effects of CO{sub 2} enrichment and tropospheric O{sub 3} on grain quality characteristics in soft red winter wheat (Triticum aestivum L.) were examined in field studies using 3 m in diam. open-top chambers. Wheat cultivars {open_quotes}Massey{close_quotes} (1991) and {open_quotes}Saluda{close_quotes} (1992) were exposed to two CO{sub 2} concentrations (350 vs. 500 {mu}mol CO{sub 2} mol{sup {minus}1}; 12 hd{sup {minus}1}) in combination with two O{sub 3} regimes (charcoal-filtered air vs. ambient air + 40 {plus_minus} 20 nmol O{sub 3} mol{sup {minus}1}, 7 hd{sup {minus}1}; Monday to Friday) from late March until maturity in June. Grain quality characteristics investigated included: test weight, milling and baking ...
The primary determinants of pulmonary disease are environmental. The same thinness and delicacy of the air-blood barrier which allows rapid exchange of oxygen and carbon dioxide also reduce its effectiveness...Full Text Available
Reciprocity is one of the defining features of social exchange and social life, yet exchange theorists have tended to take it for granted. Drawing on work from a decade-long theoretical research program, I argue that reciprocity is structured and variable across different forms of exchange, that these variations in the structure of reciprocity have profound effects on the emergence of integrative bonds of trust and solidarity, and that these effects are explained and mediated by a set of risk- and conflict-based processes. I discuss the consequences of this work for organizational theories of embeddedness and the production of social capital through network ties. Finally, I ask how the structure of networks and the structure of reciprocity are related to one another, and explore possible implications of the structure of reciprocity for exchange theorists' assumptions about actor motivations. (Contains 3 ...
... The other standards in this group deal with heat exchangers, insulation, marking, valves, hydraulic cleanliness, storage of LPG, and centrifugal fire ...
This program deals with solid waste disposal with topics/services covering: Reusable Building Materials and Large Household Items Exchange, Beneficial Use Determination, Biosolids, Certification, Compost Facil...
A specific radiochemical procedure for indium determination in semiconductor-grade silicon, using an inorganic ion exchanger (cerium oxalate) is proposed.
We describe a 2 parameter family of polygon exchange transformations parameterized by points in a square. Whenever the two parameters are irrational, the polygon exchange has periodic orbits of arbitrarily large period. We show that for almost all parameters, the polygon exchange map has the property that almost every point is periodic. However, there is a dense set of irrational parameters for which this fails. By choosing parameters carefully, the measure of non-periodic points can be made arbitrarily close to full measure. These results are powered by a notion of renormalization which holds in a more general setting. Namely, we consider a renormalization of tilings arising from the Corner Percolation Model.
The behavior of Am, Cm, Bk, Cf, Es, and other actinides, as well as Zr, on anion and cation exchangers in aqueous and water-ethanol solutions of sulfuric acid as a function of the various components of the solution has been investigated. It has been discovered that the presence of ethanol in sulfuric acid solutions causes an increase in the distribution coefficients both on cation exchangers and on anion exchangers. The possibility of the use of ion exchangers for the preconcentration and separation of transplutonium elements from U, Np, Pu, Zr, and other elements which form strong complexes with sulfate ions over a broad range of concentrations of sulfuric acid has been demonstrated.
Recent Reviews in Carcinogenesis is a service of the International Cancer Research Data Bank (ICRDB) Program of the National Cancer Institute, intended to facilitate and promote the exchange of information between cancer scientists. It contains abstracts ...
We have investigated via SQUID magnetometry and polarised neutron reflectivity the exchange-bias effect in CoO/Co sputtered multilayers. In particular, we studied the magnetisation reversal and the time relaxation of the exchange-bias field close to the coercive field H{sub c1}. Neutron intensities of all four cross sections (I++, I+-, I-+, I-) were recorded at the position of the first multilayer Bragg peak while scanning the magnetic field. From such scans we infer that the magnetisation reversal for the ascending as well as for the descending branch of the magnetic hysteresis occurs not by in-plane rotation but through domain-wall movements. The exchange-bias field, H{sub EB}, is strongly affected by thermal fluctuations. H{sub EB} decreases, following an exponential decay function with a half-life time of about 580 s at T=240 K. (orig.)
This paper presents a set of heuristics useful for optimal design of heat-exchange networks and integrated heat and power systems. These heuristics consolidate other approaches reported in the literature in a formalism useful for design purposes.
RODbaffle heat exchanger is a kind of shell-and-tube heat exchanger with eminent performance. Because of the characteristics of tube bundle support structure, fluid flow on shellside is longitudinal and periodical, and fluid flow is of symmetry in landscape orientation. According to the fluid flow characteristics on shellside and ignoring the impact of inlet, outlet and shell wall, a periodic flow unit duct was taken as the simplified model of the shellside to perform numerical simulation by using CFD code, FLUENT. It was found that the both errors in magnitude of the main fluid velocities and heat transfer coefficients between results of simulation and that of experiment or correlations are less than 10%, and the errors of pressure drop between simulation and correlation are no more than 20%. The detailed characteristics and relation of fluid flow and heat transfer on shellside of the RODbaffle heat exchanger were analyzed ...
Multiple Reggeon exchange supplies subleading logarithms that may be used to restore unitarity to the Low-Nussinov Pomeron, provided it can be proven that the sum of Feynman diagrams to all orders gives rise to such multiple Regge exchanges. This question cannot be easily tackled in the usual way except for very low-order diagrams, on account of delicate cancellations present in the sum which necessitate individual Feynman diagrams to be computed to subleading orders. Moreover, it is not clear that sums of high-order Feynman diagrams with complicated crisscrossing of lines can lead to factorization implied by the multi-Regge scenario. Both of these difficulties can be overcome by using the recently developed non-Abelian cut diagrams. We are then able to show that the sum of s-channel-ladder diagrams to all orders does lead to such multiple Reggeon exchanges. copyright 1997 The American Physical Society.
... and (3) the exchange of information; materials or perspectives. In 1977, a conference of ... their peers), to products (e.g., curriculum materials, guidebooks, or videos). We will also take ...
Proton exchange membrane (PEM) fuel cells are energy sources that have the ... for H2 /02 PEM fuel cells because their catalysts have properties suitable for 0 ...
The invention concerns a device for the energy-saving heating of fuel in the supply pipe to an internal combustion engine to regain energy from the fuel itself, particularly but not exclusively for a Diesel engine. A part of the quantity of heat added to the fuel between the tank and the injection nozzles is given up by excess fuel not to the tank, but to the fuel lifted upstream of the injection pump. The device is characterised by the fact that it has a heat exchanger, which absorbs heat from the fuel at the level of the injection pump or upstream of it, and takes this to the fuel above the injection pump. The heat exchanger is preferably mounted upstream of a filter and close to it. A bridging pipe, which may be integrated in the heat exchanger, permits the heat exchanger to be short-circuited depending on the fuel temperature.
The mutualistic interaction of plants with arbuscular mycorrhizal (AM) fungi is characterized by an exchange of nutrients. The plant provides sugars in the form of hexoses to the heterotrophic fungus...Full Text Available
The local Yb3+ magnetic susceptibility tensor was recently measured in the frustrated pyrochlore compound Yb2Ti2O7 by means of in-field polarized neutron scattering in a single crystal. A very anisotropic effective exchange tensor was derived for the Yb3+ ion. Using this result, we reinterpret here the data for the powder susceptibility in Yb2Ti2O7. We show that, in the case of a well-isolated Kramers doublet with anisotropic g and exchange tensors, the inverse susceptibility for a powder sample does not strictly obey a Curie-Weiss law at low temperature. We discuss the consequences regarding the paramagnetic Curie temperature, usually taken as a measure of the exchange/dipolar interaction, and the exotic 'slow fluctuation' ground state of Yb2Ti2O7. (fast track communication)
To understand the evolution of giant stars, it is important to pin down the masses for Cepheids. The 7- to 10-day bump Cepheids imply lower than evolutionary mass (60%). Recent theoretical work, though, indicates that for Cepheids with periods of 15 to 16 days, the best understanding of the light curves results from using evolutionary masses.
The mass-energy spectra of the fragments of thermal fission of {sup 242m}Am are measured using the time-of-flight technique. The resulting mass-yield curve and peak-to-valley ratio agree with radiochemical data. The parameters of the kinetic energy distribution of the fragments are determined for the first time. Data on the fine structure of mass spectra in the region of cold fragmentation are presented. 15 refs., 4 figs.
We investigate the influence of the turbulence forcing on the mass distributions of gravitationally unstable cores by postprocessing data from simulations of non-selfgravitating isothermal supersonic turbulence with varying resolution. In one set of simulations solenoidal forcing is applied, while the second set uses purely compressive forcing to excite turbulent motions. From the resulting density field, we compute the mass distribution of gravitationally unstable cores by means of a clump-finding algorithm. Using the time-averaged probability density functions of the mass density, semi-analytic mass distributions are calculated from analytical theories. We apply stability criteria that are based on the Bonnor-Ebert mass resulting from the thermal pressure and from the sum of thermal and turbulent pressure. Although there are uncertainties in the application of the clump-finding ...
Acoustic metamaterials with negative effective mass below a cut-off frequency are studied. An equivalent mass-spring structure is firstly proposed for such metamaterials, the effective mass is found to follow the Drude model: being negative below a specific frequency. The peculiar behavior is then verified by transmission experiments operating in the low-frequency regime. Inspired by the mass-spring model, we investigate the two-dimensional elastic waveguide with clamped boundaries and attribute the bandgap occurring below a critical frequency to negative effective mass density. The finding helps us to design a new acoustic Drude metamaterial, which enables shearing and bending deformations, in contrast to the membrane-type ones. Both simulation and experimental results show that the proposed metamaterial exhibits negative effective mass below 1200 Hz, thus ...
The thesis deals with measurement of the mass of the W boson at LEP2, based on the direct reconstruction of its decay products in the hadronic channel. A set of procedures necessary for the extraction of the W mass from the experimental data collected with the DELPHI detector in 1997 was developed (search of optimal variables for the event selection, development of a special method of kinematical reconstruction). The measured value of the mass was interpreted in the framework of the Standard Model, allowing to constrain the mass of the Higgs boson. A substantial part of the work is devoted to systematic effects due to the interactions between the hadronic decay products of the W bosons (colour reconnection and Bose-Einstein correlations), which may significantly influence the measurement of their mass. (author) 53 refs., 104 figs., 33 tabs.
High purity Fe-50mass%Cr alloys containing (C+N) in the range of 30 to 500 mass ppm were prepared and their corrosion resistance was investigated. Pitting potential in a 3.5mass%NaCl solution at 343K rose with reducing (C+N) content. Alloys containing (C+N) at less than 100 mass ppm did not sustain pitting corrosion. However, alloys containing 500 mass ppm (C+N) corroded severely in 6%FeCl_3+1/20N HCl solutions. Heat treatment at 923K was recognized as influencing corrosion resistance due to precipitation of carbonitrides only in the case of the alloy containing 500 mass ppm (C+N). (orig.).
We present new results from accurate and fully general-relativistic simulations of the coalescence of unmagnetized binary neutron stars with various mass ratios. The evolution of the stars is followed through the inspiral phase, the merger and prompt collapse to a black hole, up until the appearance of a thick accretion disk, which is studied as it enters and remains in a regime of quasi-steady accretion. Although a simple ideal-fluid equation of state with \\Gamma=2 is used, this work presents a systematic study within a fully general relativistic framework of the properties of the resulting black-hole--torus system produced by the merger of unequal-mass binaries. More specifically, we show that: (1) The mass of the torus increases considerably with the mass asymmetry and equal-mass binaries do not produce significant tori if they have a total baryonic mass ...
A metamaterial that is composed of solid viscoelastic elements with controllable properties is proposed in this Letter. This enables an adaptable and general acoustic metamaterial to be practically realised. An array of masses with a single elastic connection to a supporting viscoelastic structure, such as one that is dynamically equivalent to an array of Helmholtz resonators, only provides a system with negative effective mass. A local active control scheme applied to each of these masses can emulate additional elastic connections to the supporting structure. An array of masses with a suitable local control scheme can provide both the negative effective stiffness and mass required for negative refraction. The tuneable feedback control parameters determine the characteristics of the region...
Nucleon and meson effective masses in the nonlinear relativistic mean-field theory introducing a nonlinear {omega}-{rho} and {sigma} coupling motivated by the quark-meson coupling model is explored. It is shown that, in contrast to the usual Walecka model, not only the effective nucleon mass m{sub eff,N} but also the effective {sigma},{rho} meson masses (m{sub eff{sigma}},m{sub eff,{rho}}) and the effective {omega} meson mass m{sub eff,{omega}} are nucleon density dependent. (author)
Nucleon and meson effective masses in the nonlinear relativistic mean-field theory introducing a nonlinear #omega#-#rho# and #sigma# coupling motivated by the quark-meson coupling model is explored. It is shown that, in contrast to the usual Walecka model, not only the effective nucleon mass m_e_f_f_,_N but also the effective #sigma#,#rho# meson masses (m_e_f_f_#sigma#,m_e_f_f_,_#rho#) and the effective #omega# meson mass m_e_f_f_,_#omega# are nucleon density dependent. (author)
Recent developments in the analysis of Mira atmosphere, the determination of the pulsation mode, the problem of mass loss, and the evolution of the Mira variables are covered. Model atmospheres for Mira variables, including the opacities of the molecules expected in very late M-type atmospheres are discussed. The pulsation constant for Omicron Ceti is evaluated using T(eff) = 2900 + or - 200 K, and it is concluded that Miras are fundamental mode pulsators. The importance of molecular opacity to the driving of mass loss is evaluated, and it is pointed out that the radiation pressure on molecules is not a major factor in driving mass loss from Mira. Mass loss is considered as a factor in the calculations of the periods for Mira variables. 30 refs.
The mass of the nucleon is studied in a chiral quark-diquark model. Both scalar and axial-vector diquarks are taken into account for the construction of the nucleon state. After the hadronization procedure is used to obtain an effective meson-baryon Lagrangian, the quark-diquark self-energy is calculated to generate the baryon kinetic term as well as determine the mass of the nucleon. It turns out that both the scalar and axial-vector parts of the self-energy are attractive for the mass of the nucleon. We investigate the range of parameters that can reproduce the mass of the nucleon.
Mass distribution in 28.5 MeV alpha particle induced fission of "2"3"2Th has been determined using gamma spectrometric technique. The chain yields of 24 different fission products covering both symmetric and asymmetric mass divisions were determined. The mass distribution was found to be asymmetric with peak positions at mass numbers 96 and 136 respectively while the peak to valley ratio was 3.86. The results are compared with the available literature on 14 MeV neutron induced fission of "2"3"5U. (orig.).
Mass distribution in 28.5 MeV alpha particle induced fission of {sup 232}Th has been determined using gamma spectrometric technique. The chain yields of 24 different fission products covering both symmetric and asymmetric mass divisions were determined. The mass distribution was found to be asymmetric with peak positions at mass numbers 96 and 136 respectively while the peak to valley ratio was 3.86. The results are compared with the available literature on 14 MeV neutron induced fission of {sup 235}U. (orig.).
Isotopic analyses of radioactive materials such as irradiated nuclear fuel are of major importance for the optimization of the nuclear fuel cycle and for safeguard aspects. Among the mass-spectrometric techniques available, inductively coupled plasma mass spectrometry (ICP-MS) and thermal ionization mass spectrometry are the most frequently applied methods for nuclear applications. Because of the low detection limits, the ability to analyze the isotopic composition of the elements and the applicability of the techniques for measuring stable as well as radioactive nuclides with similar sensitivity, both mass-spectrometric techniques are an excellent amendment to classical radioactivity counting methods. The paper describes selected applications of multicollector ICP-MS in combination with c...
The acoustic hyperlens can be realized by an alternating layered structure of water and fluid with negative mass density. Based on this alternating layered principle, we propose that an acoustic metamaterial consisting of three layers in water background can be designed to replace the fluid with negative mass density. The effective mass density and bulk modulus of the system which is composed of acoustic metamaterial and water are functions of the frequency. The effective mass density of such a system is close to the negative mass density of the fluid at a specific frequency; thus an acoustic metamaterial hyperlens can be achieved.
This paper describes various eddy current probes, and their performance, which were developed at the Chalk River Laboratories of Atomic Energy of Canada. Included are probes for detecting defects at tubesheet regions in heat exchanger tubes, defects at expansion-transition regions in finned tubes, and defects in ferromagnetic tubes. All of these probes can be used with conventional commercially available instruments. (author).
Thermogalvanic corrosion of St3 steel in a temperature range from 25 to 50{degrees}C with a 3.84{degrees}C/cm gradient was studied in a neutral media flow. It is shown that the thermogalvanic effect on the pitting corrosion of water-cooled heat exchangers is decisive but dual. Depending on the composition of the cooling medium, thermogalvanic corrosion may either enhance (0.5 M NaCl) or inhibit (tap water) pitting corrosion.
A simple and effective method is presented for the sizing and passage apportionment of multistream plate-fin heat exchangers. Methods for passage arrangement are discussed, and it is shown that a symmetric or mixed passage arrangement is more efficient than a segregated arrangement. A method for assessing the relative merits of various passage arrangements is presented. The use of the methods is illustrated through a worked example.
The heavy water reactor such as Wolsung No.1 and No.2 has a purification system to purify the reactor coolant. The control system regulates the coolant temperature to protect the ion exchanger. After the fuel exchanges of operating plant, the increase of the coolant pressure makes the purification temperature control difficult. In this paper, the controllability of the control dynamics of the purification system was analysed and the optimal parameters were proposed. To reduce the effects of the flow disturbance, the feedforward control structure was proposed and analysed.
Polarized epithelial cells develop and maintain distinct apical and basolateral surface domains despite a continuous flux of membranes between these domains. The Na+/H+exchanger...Full Text Available
The electrochromatographic behavior of 25 metal ions on zirconium tungstate-impregnated papers is described. Six background electrolytes were used. On the basis of the differential mobilities of metal ions which depend on the ion-exchange properties of zirconium tungstate and the nature of complex formation with the electrolytes, some important binary and ternary separations have been achieved.
Here the authors try to dissolve some commonly held misconceptions about the operation of eddy current probes used for inspecting heat exchanger tubes. With the help of computer model results, the authors demonstrate that, for optimized operation, absolute/differential probes should be operated with coil current flowing in phase with another. This month's feature should be of interest to researchers as well as for NDT field personnel.
RIN proteins serve as guanine nucleotide exchange factors for Rab5a. They are characterized by the presence of a RIN homology domain and a C-terminal Vps9 domain. Currently three family members have...Full Text Available
Determination of Cr, Fe, Cu, Zn and Pb in drinking water preconcentrated on a chelating ion exchanger of Czechoslovak production is described. The analytical system consisted of a radionuclide source "2"3"8Pu, a Si/Li semiconductor detector and a multichannel analyzer. Results are compared with trehshold limit values recommended for drinking water. (author) 9 refs.; 2 figs.
A method has been developed for the adsorption of Sc"I"I"I employing inorganic ion exchanger zirconium phosphosilicate by batch method. Effects of various parameters have been evaluated on the percentage adsorption of Sc"I"I"I. Separation of Sc"I"I"I from various other elements is standardized. (author)
The amplitudes for the pion-nucleon charge exchange reaction of the Karlsruhe-Helsinki and the George-Washington-University partial-wave analyses are compared with those of a Regge-cut model with the aim to explore the possibility to provide high-energy constraints for theoretical baryon resonance analyses in the energy region above 2 GeV. (orig.)
Using the method of unitary transformation in combination with chiral effective field theory we derive the pion exchange contributions to the two-nucleon electromagnetic current. A formal definition of the current operator in this scheme and the power counting is presented. We discuss the implications of additional unitary transformations that have to be present to ensure the renormalizability of the one-pion exchange current. Further, we give explicit and compact results for the current in coordinate-space.
The goal of this study was to identify and characterize the hypothesized apical cation/H+exchanger responsible for K+ and/or Na+ secretion in...Full Text Available
Calculating the local spectral densities at magnetic adatoms, we estimate the variation in the Yosida-Kondo resonance due to the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction and the direct exchange between adatoms in systems of magnetic trimers on metal surfaces. The results show that the RKKY interaction leads to the gradual variation in Kondo temperature, and the direct exchange can be the origin of the drastic variation. (author)
...] gueconwpa~05-05-05 How is Macro News Transmitted to Exchange Rates? (December 2003) by Martin D. D. Evans(Georgetown University and NBER) and Richard K. Lyons(U.C. Berkeley and NBER, Haas School of Business) [Downloadable!] gueconwpa~05-05-04 A New Micro Model of Exchange Rate Dynamics (March 2004) by Martin D. D. Evans(Georgetown University and ...
A passive heat exchange enhancement structure which operates by free convection includes a flat mounting portion having a plurality of integral fins bent outwardly from one side edge thereof. The mounting portion is securable around a stovepipe, to a flat surface or the like for transferring heat from the pipe through the fins to the surrounding air by rotation-enhanced free convection.
It is desirable to avoid vibration problems by following appropriate guidelines and specifications at the design stage. Accordingly, design specifications were developed to prevent tube failures due to vibration in nuclear steam generators and liquid heat exchangers. These specifications are outlined in this report. (author). 14 refs., 2 figs.
In this report, the quantitative relation between the height equivalent to a theoretical plate (HETP) and the size of ion exchange resin is studied by enriching lithium isotopes with high pressure ion exchange displacement chromatography. The dependence of HETP on the size of the resin can be expressed as H = C x (anti r)sup( ) in which = 2.4 and it is found that Snyder's equation is suitable for such a system of isotope separation as may be explained by the simple displacement mechanism.
We have used the unique spatial sensitivity of polarized neutron and soft x-ray beams in reflection geometry to measure the depth dependence of magnetization across the interface between a ferromagnet and antiferromagnet. The new uncompensated magnetization near the interface responds to applied field, while the uncompensated spins in the antiferromagnetic bulk are pinned, thus providing a means to establish exchange bias.
This heat exchanger is a critical step in the development of the Externally Fired Combined Cycle power system, a direct-coal combustion power plant (gas turbine). SiC is the only material with the needed resistance to creep, thermal shock, and oxidation; however a protective coating is needed. Ten candidate materials were identified: alumina-based materials, materials stable with SiO, and low expansion materials. An initial screening study should be performed.
A radiochemical method of separation of {sup 203}Hg from {sup 181}Hf is described. The method involves separation by Dowex 50W- X 8, 100-200 mesh, cation exchange resin using 1 M hydrochloric acid as the eluant. The chemical yield for the separation of mercury is > 85% and the decontamination factor is >10{sup 4}. The {sup 181}Hf can be eluted from the column by 4 M HCl.
Arf GTPases control vesicle formation from different intracellular membranes and are regulated by Arf guanine nucleotide exchange factors (GEFs). Outside of their conserved catalytic domains, known...Full Text Available
This patent describes a nuclear system comprising a containment airspace in which a nuclear reactor pressure vessel is disposed there being a reactor core within the pressure vessel. It comprises a heat exchanger elevated a distance above the pressure vessel; a pool of water surrounding the heat exchanger; means for venting the pool of water to an environment outside the containment; a heat exchanger entry conduit within the containment, the entry conduit having an open lower end communicating with the containment space, and an upper end connected to the heat exchanger, water-containing heated fluid present in the containment airspace incident a pressure vessel loss of coolant event entering and flowing through the entry conduit into the heat exchanger for cooling the fluid to convert water vapor therein to a condensate and separate non-condensable gasses therefrom; a gravity driven ...
Hybrid density functionals, which replaces a fraction of a density functional theory exchange with exact Hartree-Fock (HF) exchange, have been used to study the structural, magnetic, and electronic properties of ?-Pu. The fractions of exact Hartree-Fock exchange used were 25%, 40%, and 55%. Compared to the pure PBE functional, the lattice constants expanded with respect to the experimental value when the PBE-HF hybrid functionals were applied. For pure PBE and hybrids functionals with HF exchange amounts of 25% and 40%, the ground state structure was anti-ferromagnetic, while for 55% HF contribution the ground state was non-magnetic. The 5f electrons tend to exhibit slight delocalization or itinerancy for the pure PBE functional and well-defined localization for the hybrid functionals, with the degree of 5f electron localization increasing with the amount of HF exchange. Overall, ...
Radian received twelve sections of heat exchanger tubing from the Magma Electric Company's 10MW(e) East Mesa binary geothermal power plant. Three tube sections were received from each of four shell and tube heat exchangers (HX1, Hx6, HX8, and Hx10) of the isobutane vaporizer train. All samples were taken from the upper few rows of tubes. Two months later, four more tube sections were received. These four sections were taken from the lower rows of heat exchangers 1, 6 (two sections), and 10. Radian was requested to investigate the cause of severe pitting failure of these heat exchanger tubes. This report is part of a continuing DOE effort to gain insight into the service life of component materials employed in geothermal energy utilization.
It was previously reported that the tritium tracer method is useful for the quantitative consideration of hydrogen behavior in coal during coal liquefaction reaction. Tetralin is excellent hydrogen donating solvent, and is considered as one of the model compounds of coal. In this study, effects of H2S and H2O on the hydrogen exchange reaction between tetralin and gaseous hydrogen labeled by tritium were investigated. It was suggested that the conversion of tetralin and the hydrogen exchange reaction between gaseous hydrogen and tetralin proceed through the radical reaction mechanism with a tetralyl radical as an intermediate product. When H2S existed in this reaction, the hydrogen exchange yield increased drastically without changing the conversion yield. This suggested that the hydrogen exchange reaction proceeds even in the reaction where radical does not give any effect. In the case of H2O addition, ...
Hybrid density functionals, which replace a fraction of density functional theory (DFT) exchange with exact Hartree-Fock (HF) exchange, have been used to study the structural, magnetic, and electronic properties of ?-Pu. The fractions of exact Hartree-Fock exchange used were 25%, 40%, and 55%. Compared to the pure PBE functional, the lattice constants expanded with respect to the experimental value when the PBE-HF hybrid functionals were applied. For pure PBE and hybrid functionals with HF exchanges amounts of 25% and 40%, the ground state structure was anti-ferromagnetic, while for 55% HF contribution the ground state was non-magnetic. The 5f electrons tend to exhibit slight delocalization or itinerancy for the pure PBE functional and well-defined localization for the hybrid functionals, with the degree of 5f electron localization increasing with the amount of HF exchange. Overall, ...
Hybrid density functionals, which replace a fraction of density functional theory (DFT) exchange with exact Hartree-Fock (HF) exchange, have been used to study the structural, magnetic, and electronic properties of #delta#-Pu. The fraction of exact Hartree-Fock exchange used were 25%, 40%, and 55%. Compared to the pure PBE functional, the lattice constants expanded with respect to the experimental value when the PBE-HF hybrid functionals were applied. For pure PBE and hybrid functionals with HF exchanges amounts of 25% and 40%, the ground state structure was anti-ferromagnetic, while for 55% HF contribution the ground state was non-magnetic. The 5f electrons tend to exhibit slight delocalization of itinerancy for the pure PBE functional and well-defined localization for the hybrid functionals, with the degree of 5f electron localization increasing with the amount of HF exchange. ...
It is needless to say that one of the most important roles of the condensate demineralizer in Japanese boiling water reactors (BWR) is to eliminate such impurities during accidental occurrence of sea water leakage from condensate cooling system. Ion exchange resins packed in condensate demineralizer have also been expected to decrease crud, or corrosion products (CP) in condensate water in order to finally reduce activated corrosion products (ACP) in the reactor coolant loop. It is perceived that crud removal ability of a condensate demineralizer has been improved year by year. And we call this phenomenon as `Aging Effect`. Typical property changes of aged cation exchange resin consisted of an increase of water retention capacity and a change of surface texture. Based on these findings, we formulated a new concept and developed new gel type ion exchange resins for the better crud removal. The results from column tests using ...
A heat transfer (condenser) of a domestic freezer was tested in a vertical channel in order to study the influence of the chimney effect in the optimization of the heat transfer coefficient. The variation of the opening of the channel, position and the heating power of the heat exchanger in the heat transfer coefficient was considered. The influence of the surface emissivity on the heat transfer by thermal radiation was studied with the heat exchanger testes without paint and with black paint. The air velocity entering the channel was measured with a hot wire anemometer. In order to evaluate the chimney effect, the heat exchanger was testes in a open ambient. This situation simulates its operational conditions when installed on the freezer system. The variables collected in the experimental procedures was gathered in the form of dimensionless parameters as Nusselt, Rayleigh, Grashof and Prandtl numbers, and dimensional ...
Determining the type of matter that is inside a neutron star (NS) has been a long-standing goal of astrophysics. Despite this, most of the NS equations of state (EOS) that predict maximum masses in the range 1.4-2.8 solar masses are still viable. Most of the precise NS mass measurements that have been made to date show values close to 1.4 solar masses, but a reliable measurement of an over-massive NS would constrain the EOS possibilities. Here, we investigate how optical astrometry at the microarcsecond level can be used to map out the orbits of High-Mass X-ray Binaries (HMXBs), leading to tight constraints on NS masses. While previous studies by Unwin and co-workers and Tomsick and co-workers discuss the fact that the future Space Interferometry Mission should be capable of making such measurements, the current work describes detailed simulations for 6 HMXB ...
The paper reports on the results of hydrodynamical simulations of the late phase of the common envelope stage of a binary consisting of a 2-solar mass red giant and a 1-solar mass main-sequence companion. The numerical results demonstrate that sufficient energy is released from the orbit to eject the mass within the common envelope without requiring the main-sequence companion to spiral into the white dwarf core of the red giant star. At the end of the simulation the orbital decay time scale increases rapidly to more than 160 yr. The long decay time scale reflects the removal of mass from the common envelope and its subsequent spin-up to near corotation. The ratio of the orbital decay time scale to the mass-loss time scale from the common envelope increases to more than 700, and the mass contained within the common envelope decreases to about 0.01 solar ...
A two-dimensional (2D) lattice model with anisotropic resonant microstructures is found to provide an anisotropic band gap structure. A 2D continuum with anisotropic effective mass density is introduced to represent this lattice system. Two methods are proposed to derive the equivalent continuum. In the first method, the effective mass density of the equivalent continuum is obtained by matching the dispersion relations for harmonic waves propagating in the principal directions. The second approach employs an approximate estimation of the effective mass density by volume-averaging an effective mass that represents the resonant microstructure. For both equivalent continuum models, the effective mass density is frequency-dependent and may become negative in certain frequency ranges. Subsequen...
The mass asymmetry of fragments from nuclear fission of heavy nuclei is reviewed. While mass asymmetry is a common and well-known phenomenon for low-energy fission of the lighter actinides, more recent experiments have demonstrated that, for the heaviest actinides, the mass distribution switches to a symmetric one. On the other hand, it has been discovered that, though for fissioning nuclei with mass numbers A< or [approx]225 the mass distribution is basically symmetric, an asymmetric component is clearly to be identified for nuclei down to the Pb-region. In the absence of a generally accepted dynamical theory of fission, the above experimental findings are discussed in terms of static energy considerations. Triggered from the outset by the structure of the potential energy surface at the saddlepoint, the energy balance at the scission point between the available energy (Q-value) ...
The mass asymmetry of fragments from nuclear fission of heavy nuclei is reviewed. While mass asymmetry is a common and well-known phenomenon for low-energy fission of the lighter actinides, more recent experiments have demonstrated that, for the heaviest actinides, the mass distribution switches to a symmetric one. On the other hand, it has been discovered that, though for fissioning nuclei with mass numbers A< or #approx#225 the mass distribution is basically symmetric, an asymmetric component is clearly to be identified for nuclei down to the Pb-region. In the absence of a generally accepted dynamical theory of fission, the above experimental findings are discussed in terms of static energy considerations. Triggered from the outset by the structure of the potential energy surface at the saddlepoint, the energy balance at the scission point between the available energy (Q-value) ...
The thermal performance of an automotive radiator plays an important role in the performance of an automobile's cooling system and all other associated systems. For a number of years, this component has been given little attention with very little changing in its manufacturing cost, operation and geometry. As opposed to the old tubular heat exchanger configurations used in automotive radiators, plate heat exchangers currently form the backbone of today's process industry with their advanced performance reaching levels the designers of tubular heat exchangers can only dream of. The aluminium roll-bonding technique widely used in manufacturing the cooling compartments for domestic refrigeration units is one of the cheapest methods for heat exchanger manufacturing. Using this technique, it is possible to manufacture a wide range of heat exchanger configurations that ...
The 177 underground storage tanks at the DOE's Hanford Site contain an estimated 180 million tons of high-level radioactive wastes. It is desirable to remove and concentrate the highly radioactive fraction of the tank wastes for vitrification. Resorcinol-formaldehyde (R-F) resin, an organic ion-exchange resin with high selectivity and capacity for the cesium ion, which is a candidate ion-exchange material for use in remediation of tank wastes. The report includes information on the structure/function analysis of R-F resin and the synthetic factors that affect performance of the resin. CS-100, a commercially available phenol-formaldehyde (P-F) resin, and currently the baseline ion-exchanger for removal of cesium ion at Hanford, is compared with the R-F resin. The primary structural unit of the R-F resin was determined to consist of a 1,2,3,4-tetrasubstituted resorcinol ring unit while CS-100, was composed mainly of a ...
As the last step of urinary acidification, the inner medullary collecting duct (IMCD) is thought to secrete protons into the tubular lumens by means of a H(+)-translocating adenosinetriphosphatase (H(+)-ATPase). However, recent studies have also shown the existence of Na(+)-H+ exchange activity in IMCD cells. Although the physiological function of the antiporter in IMCD cells is unknown, activation of Na(+)-H+ exchange in other cell-culture systems has been suggested to be closely associated with the process of cell growth. Thus presence of Na(+)-H+ exchange may relate to the growth phase of these cells. To examine intracellular pH (pHi) regulation in growing IMCD cells, we studied proton transport by Na(+)-dependent and Na(+)-independent mechanisms by microfluorimetry using the pHi-sensitive dye 2',7'-bis(carboxyethyl)-5,6-carboxyfluorescein acetoxymethyl ester (BCECF/AM). Actively growing cells, defined ...
Several low-mass models with an inhomogeneous radiative core and a convective envelope are investigated, the entire core or its upper portion being treated as a zone of neutral stability. Mixing by convective overshoot will then give rise to unstable structure.
The scaling of reproductive parameters to body size is important for understanding ecological and evolutionary patterns. Here, we derived allometric relationships for the number and mass of seeds, eggs...Full Text Available
We calculate the light `glueball' mass spectrum in N_f=2 lattice QCD using a fermion action that is non--perturbatively O(a) improved. We work at lattice spacings a~0.1 fm and with quark masses that range down to about half the strange quark mass. We find the statistical errors to be moderate and under control on relatively small ensembles. We compare our mass spectrum to that of quenched QCD at the same value of a. Whilst the tensor mass is the same (within errors), the scalar mass is significantly lighter in the dynamical lattice theory, by a factor of ~0.84 +/- 0.03. We discuss what the observed m_q dependence of this suppression tells us about the dynamics of glueballs in QCD. We also calculate the masses of flux tubes that wind around the spatial torus, and extract the string tension from these. As we decrease the quark ...
This paper describes a system for fast mass spectrometric characterization of high-temperature outgassing measurements and measuring the total quantity of gas evolved for boron nitride. 2 references, 1 figure, 2 tables.
BackgroundMass treatment to trachoma endemic communities is a critical part of the World Health Organization SAFE strategy. However, non-participation may not be at random, affecting...Full Text Available
Mass Balance and Present-day Antarctic Rebound and Gravity Change. Erik R. Ivins , Eric Rignot, Xiaoping Wu, Carol A. Raymond (JPLKaltech, 300-233,4800 Oak ...
We have developed a method for dissecting single neurons from the nematode Ascaris suum, in order to determine their peptide content by mass spectrometry (MS). In this paper,...Full Text Available
Three-flavor lattice QCD simulations and two-loop perturbation theory are used to make the most precise determination to date of the strange-, up-, and down-quark masses, $m_s$, $m_u$, and $m_d$, respectively. Perturbative matching is required in order to connect the lattice-regularized bare- quark masses to the masses as defined in the \\msbar scheme, and this is done here for the first time at next-to-next-to leading (or two-loop) order. The bare-quark masses required as input come from simulations by the MILC collaboration of a highly-efficient formalism (using so-called ``staggered'' quarks), with three flavors of light quarks in the Dirac sea; these simulations were previously analyzed in a joint study by the HPQCD and MILC collaborations, using degenerate $u$ and $d$ quarks, with masses as low as $m_s/8$, and two values of the lattice spacing, with chiral ...
The first cell lineage specification in mouse embryo development is the formation of trophectoderm (TE) and inner cell mass (ICM) of the blastocyst. This article is to review and discuss the...Full Text Available
A liquid chromatography/tandem mass spectrometric (LC/MS/MS) assay was developed for the quantitative determination of salirasib (S-trans, trans-farnesylthiosalicylic acid,...Full Text Available
Improved NMR detection of mass limited samples can be obtained by taking advantage of the mass sensitivity of microcoil NMR, while throughput issues can be addressed using multiple, parallel...Full Text Available
Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MS) has been explored widely for DNA sequencing. The major requirement for this method is that the DNA sequencing fragments...Full Text Available
Charge reduction electrospray mass spectrometry (CREMS) reduces the charge states of electrospray-generated ions, which concentrates the ions from a protein into fewer peaks spread over a larger...Full Text Available
The binding mode of telomestatin to G-quadruplex DNA has been investigated using electrospray mass spectrometry, by detecting the intact complexes formed in ammonium acetate. The mass measurements show...Full Text Available
The diagnostic accuracy of computed tomography (CT) in several patterns of thoracic and abdominal fatty masses, has been examined. In selected cases our findings overlap the features of the recent literature. The possibility of surgical therapy in peculiar cases of adipose deposits, commonly esteemed benign, is considered.
Discrete masses are commonly detected during mammographic screening and most such lesions are benign. For lesions without pathognomonically benign imaging features that are still regarded likely to...Full Text Available
Validation of body-mass relationships requires a careful statistical analysis of data of normal weight individuals. BMI (ratio between body mass and square of body height) and BSI values (ratio between...Full Text Available
The validation parameters for pharmaceutical analyses were examined for the accelerator mass spectrometry measurement of 14C/C ratio, independent of chemical separation procedures....Full Text Available
Derivations are made for the mass and the mass-turnover time scale of an accretion disk as a function of the accretion rate, the observed disk radius, the non-viscous disk radius, and two parameters. These parameters depend on the effectiveness of viscosity and tidal angular momentum loss. Application is made to DQ Herculis.
Advanced developments in computer technologies offer exciting opportunities for new distribution tools and applications in various fields of physics. The convenient and reliable exchange of data is clearly an important component of such applications. Therefore, in 2003, the A+M Data Unit initiated within the collaborative efforts of the DCN (Data Centre Network) a new standard for atomic, molecular and particle surface interaction data exchange (AM'PSI) based on XML (eXtensible Markup Language). A working group composed of staff from the IAEA, NIST, ORNL and Observatoire Paris-Meudon meets biannually to discuss progress made on the XML schema, and to foresee new developments and actions to be taken to promote this standard for AM/PSI data exchange. (author)
A solar energy desalination process utilizing solar radiation directly for the evaporation of salt water is described. Ambient air takes on water vapor as the air passes through an evaporative medium. It is then directed between a saline water-covered, solar absorbing surface and a solar collecting housing. The resulting heated and moisture-saturated air is cooled in a heat exchange means where condensation of fresh water occurs. Simultaneously, cool salt water is utilized as the cooling water in the heat exchange means, and takes on the heat of condensation given up by the condensing vapor. The heated salt water from the heat exchange means is partially directed over the solar absorbing surface, and at least a portion of it is also directed to wet the evaporative medium. Several optional sub-processes are described for operation of the system during periods of reduced insolation, and an alternative process is described for ...
A simple tube-in-tube heat exchanger system for thermal energy storage employing stearic acid as PCM has been investigated. The performance and heat transfer characteristics of such a system were studied. Phase transition temperature range and times were measured and the speed of the phase transition front was computed. The melting front was found to move in the radial direction inward as well as in the axial direction from the top toward the bottom of the phase change material PCM tube. The speed of the melting front is enhanced by a convection heat transfer mechanism in the melted PCM. The heat transfer rate and, consequently, phase transition time can be altered by changing the water inlet temperature to the heat exchanger. In addition, a faster phase transition is realized by placing the heat exchanger in a horizontal position rather than a vertical one. (Author)
In the field of international human resource management, studies have seldom examined organizational justice, social exchange, and psychological contract together as important factors in influencing the expatriate adjustment process. The purpose of this research is to fill the research gap by examining these factors and their relationships with expatriate adjustment. The researcher conducted a survey of Taiwanese business expatriates during the first quarter of 2007, collecting 219 valid samples for analysis. A hierarchical regression model was used to test the research framework hypotheses, which showed that expatriates' perception of organizational justice has a positive influence both on their perceptions of social exchange and on their psychological contract fulfillment. Expatriates' p...
Bismuth radioisotopes, produced by 50-MeV proton bombardment of a lead target in a cyclotron, are separated from the lead target material by ion-exchange chromatography on a column containing 5.0 ml of Chelex 100. After a decay period of 24 hr, the /sup 203/Pb formed in situ is eluted from the column and then separated from /sup 200/Tl and /sup 201/Tl on a second ion-exchange column containing 0.5 ml of Chelex 100. Separations are sharp and carrier-free /sup 203/Pb is obtained.
Active Process Water (APW) System, provided as unitized closed loop system in Tarapur Atomic Power Project Units-3 and 4, serves to remove heat from various heat exchangers. One of the important loads served by APW system is shutdown cooling heat exchangers and if APW shutdown is taken then reactor cannot be maintained in cold shutdown condition. It is estimated that after 7 days of reactor shutdown, if about 20% of the normal cooling flow to shutdown cooling heat exchangers is provided then along with keeping PHT in cold shutdown state, reactor components, moderator, end shield water, calandria vault water and calandria vault concrete temperature can be maintained within technical specification limits for extended duration. (author)
Theoretical investigations of fatty acids as a phase change material (PCM) for energy storage system have been conducted in this study. The selected fatty acids were capric acid, lauric acid, myristic acid, palmitic acid and stearic acid. For the two-dimensional simulation model based on the enthalpy approach, calculations have been made for the melt fraction with conduction only. Glass, stainless steel, tin, aluminium mixed, aluminium and copper were used as heat exchanger materials in the numerical calculations. Theoretical results show that capric acid was found good compatibility with latent heat storage system. The large value of thermal conductivity of heat exchanger materials did not make significant contribution on the melt fraction. (author)
Single stage separation factors ..cap alpha.. have been determined for /sup 6/Li and /sup 7/Li between lithium ions in methanol and complexed ions with a cryptand (2 sub(B), 2, 1) polymer. The /sup 6/Li was concentrated in the cryptand. The separation factors were compared with the values of other chemical exchange systems. The maximum enrichment factor obtained was epsilon = 0.047 +- 0.002. The figure is one of the greatest in the chemical exchange reactions without valence change and almost 10 times larger than the values of ion exchangers. The variation in ..cap alpha.. depending on the chemical species was small in the non-aqueous system. High enrichment of lithium isotopes was expected to be achievable by means of the chromatographic application of the cryptand (2 sub(B), 2, 1).
A technique is proposed to generate electron beam with ultralow transverse emittance through laser assisted transverse-to-longitudinal emittance exchange. In the scheme a laser operating in the TEM10 mode is used to interact with the electron beam in a dispersive region and to initiate the emittance exchange. It is shown that with the proposed technique one can significantly downsize an x-ray free electron laser (FEL), which may greatly extend the availability of these light sources. A hard x-ray FEL operating at 1.5 {angstrom} with a saturation length within 30 meters using a 3.8 GeV electron beam is shown to be practically feasible.
An aliphatic thiol ligand of CuInS2/ZnS core/shell quantum dots is replaced with a hydroxyl-terminated thiol ligand by utilizing `on-off state' of ligands during growth stage of the quantum dots. After the ligand-exchange, negligible differences were observed on both photoluminescence spectrum and luminescent quantum efficiency. The reason for the high retention of luminescent efficiency comes from no local agglomeration and no surface deterioration of QDs. It is also observed that 70% of initial ligands are exchanged by the replacing ligand, determined by FT-IR and 1H NMR. The proposed method provides the quantum dots with an excellent dispersibility in polar solvents, supported by identical luminescence decay characteristics of the QDs.
Liquid radioactive waste treatment method of using evaporator was widely used from Kori 1 to Uljin 3 and 4, but a liquid radioactive waste treatment equipment that uses an ion exchange method instead of an evaporator was adopted aiming to minimize amount of radioactive waste and radiation exposure. However, the same equipment was introduced and applied for the first time in Korea and had experienced difficulties in securing credibility for the equipment and handling of liquid radioactive waste with inadequate data about performance and experience in operation and maintenance. In this study, examination, application and effect analysis was performed on the optimization measure for handling liquid radioactive waste of Yonggwang Nuclear Power Unit 5 and 6(YGN 5 and 6) that applies an ion exchange method
The effect of water shortage on growth and gas exchange of maize grown on sandy soil (SS) and clay soil was studied. The lower soil water content in the SS during vegetative growth stages did not affect plant height, above-ground biomass, and leaf area index (LAI). LAI reduction was observed on the SS during the reproductive stage due to early leaf senescence. Canopy and leaf gas exchanges, measured by eddy correlation technique and by a portable photosynthetic system, respectively, were affected by water stress and a greater reduction in net photosynthetic rate (A N) and stomatal conductance (g s) was observed on SS. Chlorophyll and carotenoids content was not affected by water shortage in either condition. Results support two main conclusions: (1) leaf photosynthetic capacity was unaffec...
As the main forestry species in the Canary Islands (Spain), Pinus canariensis is frequently used in afforestation programs. Several nursery techniques are commonly employed to modify its morphology and physiology with the aim of improving post-planting survival and growth. In this work, we studied how fertilization and light regime treatments applied during the nursery period modify biomass allocation patterns and produce effects in gas exchange and root hydraulic conductance. Seedlings were grown for a 6-month period in the nursery under two light regimes (full sunlight and 40% PAR reduction), and three fertilization levels were applied in each light regime. Morphology, biomass allocation patterns, leaf gas exchange and hydraulic conductance of the whole root system were evaluated. Fertil...
The CKK-70 400/200 NN telephone exchange in the Nowa Ruda mine in Lower Silesia was used with the JAUL-CAMAC linear subscriber system. The CKK-70 telephone exchanges were supplied without a system for identification of calling subscribers at the ground surface. A modified identification system developed by the Nowa Ruda mine for identifying calling subscribers is evaluated. Its design is shown in 2 schemes and operation is discussed. The identification system was tested over 6 years. Tests showed it to be reliable and uncomplicated. The modified system for identification of calling subscribers adapted for conditions of underground coal mines has been tested in other mines (1 Maj, Piast, Knurow and Staszic). Recommendations for use of the modified system are made.
A Process for yellow cake production from local Euxenite was developed in Bench Scale by using sulphuric acid digestion with simultaneously ion-exchange and solvent extraction purification steps. Uranium was then precipitated as uranium diuranate by ammonia solution. Equipment used in this process includes : digestion vessels, columnar ion-exchange, solvent extraction and precipitation units Ore feed to the process could be adjusted up to 2 kilogram per day (8 hours operation) with yellow cake product purity meet the requirement of Usaec standard of about 10-50 gram per day. Included in this experiment are the leaching characteristics of the ore, the design and construction of continuous columnar 4-cycle ion exchange unit, determination of the extraction and stripping stages of a gravity flow mixer-settler and the design and construction of continuous yellow cake precipitation unit with large grain size and high density ...
The evolution of these new ion-exchange resins hinges upon an understanding of the chemistry of actinide metal complexes as they exist in solution and when interacting with the cationic sites. Molecular modeling of electrostatic interactions between the metal complex and the cationic substrate is used to help visualize uptake mechanisms and, eventually, to predict optimized coordination sites. Thus, these new materials integrate the fields of ion-specific chelation and ion-exchange technology. Synthesized resins contain cationic sites designed to facilitate the uptake of plutonium nitrato complexes from high-nitrate solutions, and they exhibit distribution coefficients that are up to 10 times higher than those observed for commercial resins. Additionally, some new resins show surprisingly large Kd`s for anionic complexes of Am(III) and U(VI).
The magnetic three spin-1/2 model for nanometer-scale molecular cluster V15 is analyzed with the emphasis on the origin of the mixing of different spin levels in the resonance fields that is generally important for the problem of single molecular magnets. The zero-field splitting in the ground quadruplet (two Formula Not Shown levels) is shown to depend mainly on the normal component of AS exchange meanwhile the zero-field splitting in the excited Formula Not Shown multiplet is a second order effect with respect to in-plane components of AS exchange. The normal component of the AS exchange is shown to lead to the exact crossing of the magnetic sublevels at the arbitrary direction of the field. The positions of two crossing/anticrossing points in the ground manifold depend mainly on the iso...
A process for separation of actinides and technetium from reprocessing high level liquid waste has been developed, the CTH-process. The main parts are three consecutive solvent extraction cycles followed by an optional step for sorption on inorganic ion exchangers. The first extraction cycle removes and recovers uranium, neptunium, and plutonium by extraction with HDEHP. The second extraction cycle separates technetium and nitric acid from the waste using TBP. In the third extraction cycle Am and Cm are separated from the waste using HDEHP. The actinide free waste is then passed through inorganic ion exchangers to remove most of remaining radionuclides. The process has been tested on an authenic HLLW solution. A decontamination factor > 10/sup 5/ for alpha emitters was measured for the solvent extraction process and the sorption on inorganic ion exchangers gave a decontamination factor > 3x10/sup 4/ for beta emitters.
The evaluation of the bactericidal effect of different silver-containing materials where silver is available as Ag^+ (silver nitrate and different silver-exchanged zeolites), as metallic Ag^0 (commercial silver nanoparticles) or as oxide (silver (I) oxide) was carried out in order to elucidate the importance of the bioavailability of silver (i.e., as free ions, metallic particles, combination of them, clusters, complexes, partially soluble or insoluble salts, etc.) on its bactericidal action. For the different materials tested, their bactericidal effect is ordered in the following sequence: AgNO"3>Ag-ZSM-5>Ag"2O>commercial silver-exchanged zeolite (granular)>commercial silver-exchanged zeolite (pellets)>Ag nanoparticles. In general, as the content of bioavailable ionic silver increases, th...
The competitive adsorption of nitrate, chloride and carbonate in layered double hydroxides (LHD) with the general formula Formula Not Shown was investigated. Both normal ion exchange by exposure to a solution containing different anions, as well as addition of calcined material to solution thereby exploiting the memory effect of LDHs was studied. Changes in the interlayer anion changed the interlayer spacing of the LDH. The order of preference of intercalation was Formula Not Shown . When multiple anions were present in the exchange solution, LDHs with several distinct interlayer spacing were produced indicating that LDHs with different anions in the interlayer existed at the same time. However for extended exchange times (14days) where high concentrations of carbonate anion were present, ...
Formulae are obtained for the angular correlation function of inelastically scattered ..cap alpha.. particles and ..gamma.. quanta of a pure EL multipolarity, which are emitted by an excited nucleus, in the case of exchange processes, if distortions are introduced into the eikonal approximation. The matrix element of the exchange processes is considered as a coherent sum of contributions from two mechanisms: replacement and stripping of a heavy particle. Concrete calculations are performed for the reaction /sup 12/C(..cap alpha.., ..cap alpha..'..gamma..)/sup 12/C. The obtained results show that the developed formalism enables one to get an agreement between the theoretical angular correlation functions with the experimental data at reasonable values of the calculation parameters.
Anion-exchange chromatography of element 105, dubnium (Db), produced in the {sup 248}Cm({sup 19}F, 5n){sup 262}Db reaction is investigated together with the homologues Nb and Ta, and the pseudo-homologue Pa in 13.9 M hydrofluoric acid (HF) solution. The distribution coefficient (K{sub d}) of Db on an anion-exchange resin is successfully determined by running cycles of 1702 chromatographic column separations. The result clearly indicates that the adsorption of Db on the resin is significantly different from that of the homologues and that the adsorption of anionic fluoro complexes of these elements decreases in the sequence of Ta{approx}Nb>Db{>=}Pa. (orig.)
Anion-exchange chromatography of element 105, dubnium (Db), produced in the "2"4"8Cm("1"9F, 5n)"2"6"2Db reaction is investigated together with the homologues Nb and Ta, and the pseudo-homologue Pa in 13.9 M hydrofluoric acid (HF) solution. The distribution coefficient (K_d) of Db on an anion-exchange resin is successfully determined by running cycles of 1702 chromatographic column separations. The result clearly indicates that the adsorption of Db on the resin is significantly different from that of the homologues and that the adsorption of anionic fluoro complexes of these elements decreases in the sequence of Ta#approx#Nb>Db#>=#Pa. (orig.)
After presenting a general account of the observed global properties of single stars of low, intermediate, and high mass, together with their theoretical Hertzsprung-Russell diagram evolution, attention is given to the observed properties of various evolved close binaries and to an assessment of the value of comparisons between observation and crude theory in characterizing the physics of mass transfer within interacting binary systems. Detailed consideration is then undertaken of such topics as stellar evolution in globular clusters, interior star changes due to nucleosynthesis and mixing, asymptotic giant branch stars of intermediate mass, the response of white dwarfs in binary systems to mass accretion, and scenarios for binary star evolution tending toward close white dwarf pairs.
We investigate several varying-mass dark-matter particle models in the framework of phantom cosmology. We examine whether there exist late-time cosmological solutions, corresponding to an accelerating universe and possessing dark energy and dark matter densities of the same order. Imposing exponential or power-law potentials and exponential or power-law mass dependence, we conclude that the coincidence problem cannot be solved or even alleviated. Thus, if dark energy is attributed to the phantom paradigm, varying-mass dark matter models cannot fulfill the basic requirement that led to their construction.
Energy level schemes are derived from gamma spectroscopy of several medium-mass deformed nuclei by studying the decay or proton and #alpha# nuclear spectroscopic data. Some new isomeric studies are established among which is the 31 y "1"7"8Hf isomeric state for which Isup(#pi#), K was determined to be 16"+, 16. A four quasi-particle configuration was assigned to this state at 2447.5 +- 2.5 KeV. Atomic masses have been calculated from various measurements and, on the basis of mass formulae extrapolated to neighboring mass regions.
The mass distribution of the Sombrero Galaxy, NGC 4594, is calculated in order to investigate the suspicion that the rotational velocity of the galactic gas does not measure the circular velocity in the galaxy. It is shown that the H II rotation velocities are much less than circular in the central 35 arcsec of the galaxy, and that the suspicion is correct. Thus, the H II rotation velocities cannot be used to measure the mass distribution. The absorption-line rotation curve is used to derive the mass distribution, and it is found that the M/L ratio is nearly constant. It is concluded that the visible matter is self-gravitating at least in the central 180 arcsec. 44 references.
The measurements of the nuclear decay of actinide isotopes and the evaluation of the radioactive properties of nuclide with the mass 242 is discussed in this paper.
Using the finite-range regularisation (FRR) of chiral effective field theory, the chiral extrapolation formula for the vector meson mass is derived for the case of partially-quenched QCD. We re-analyse the dynamical fermion QCD data for the vector meson mass from the CP-PACS collaboration. A global fit, including finite lattice spacing effects, of all 16 of their ensembles is performed. We study the FRR method together with a naive polynomial approach and find excellent agreement ~1% with the experimental value of M_rho from the former approach. These results are extended to the case of the nucleon mass.
... analyzer section for angle resolved measurements, and a thin film evaporator with a quartz crystal microbalance to measure the mass deposition. ...
The method of spectral disentangling has now created the opportunity for studying the chemical composition in previously inaccessible components of binary and multiple stars. This in turn makes it possible to trace their chemical evolution, a vital aspect in understanding the evolution of stellar systems. We review different ways to reconstruct individual spectra from eclipsing and non-eclipsing systems, and then concentrate on some recent applications to detached binaries with high-mass and intermediate-mass stars, and Algol-type mass-transfer systems.
Isospin-breaking effects in the baryonic sector are studied in the framework of a medium-modified Skyrme model. The neutron-proton mass difference in infinite, asymmetric nuclear matter is discussed. In order to describe the influence of the nuclear environment on the skyrmions, we include energy-dependent charged and neutral pion optical potentials in the s- and p-wave channels. The present approach predicts that the neutron-proton mass difference is mainly dictated by its strong part and that it strongly decreases in neutron matter. (orig.)
In our previous theoretical analyses, solubility-limited mass transfer from waste solids applies if a species is at a constant elemental concentration in liquid at the waste surface. For an element with isotopes that decay appreciably during the time of interest, a solubility boundary condition results in a time-dependent boundary concentration of each isotope. Here we present mass-transfer equations that include the effects of isotopic decay boundary conditions. 9 refs., 1 fig.
The influence of rigid-body and differential rotation and of a fine-scale chaotic magnetic field and a poloidal magnetic field on the minimum mass of a main-sequence star is investigated. It is shown that rotation and a magnetic field with an energy equal to 10--20% of the star's gravitational energy increase the minimum mass of a main-sequence star by 1.5--2 times.
Analytical solutions are derived for a flow in a semi-infinite vertical porous medium with heat and mass transfer. When the temperature and mass concentration are uniform a constant pressure is possible and sustains a fully developed flow. Thereafter there is a small perturbation on the wall temperature and concentration and the subsequent two-dimensional problem is tackled for a large Prandtl number, free convection parameters and small Reynolds number. The heat transfer rate at the wall is discussed quantitatively.
The "texture zero mass matrices" for the quarks and leptons describe very well the flavor mixing of the quarks and leptons. We can calculate the angles of the unitarity triangle. We expect the angle alpha of the unitarity triangle to be 90 degrees. The masses of the neutrinos can be calculated - they are very small, the largest neutrino mass is 0.05 eV. We calculated the matrix element of the mixing matrix, relevant for the reactor mixing angle. It can be measured in the near future in the DAYA BAY experiment.
are you exchanging data or metadata through specific agreements with a defined number of partners? or are you intending to make data or metadata available in a more "open" environment, with the expectation that it may be used by a potentially unlimited number of services? ...
the exchange of experience and ideas in the social, political and economic areas. ...the fast-changing, high-risk and short-term nature of these network relationships is seen to conflict with the slow ...incremental process of change characteristic of the German social-market model.
According to the author Austria has a specific interest in the fields of information exchange, mutual assistance, and liability. The problem of proximity to the border has become insignificant after Chernobyl. Austria aspires to get rights of participation following the model of the Netherlands. (CW).
The structure of the skin in the epauletted fruit bat (Epomophorus wahlbergi) wing and body trunk was studied with a view to understanding possible adaptations for gas metabolism and...Full Text Available
Alzheimer's disease (AD) is the most common form of dementia in the elderly. Although traditionally considered a disease of neurofibrillary tangles and amyloid plaques, structural and functional changes...Full Text Available
Superconductivity in A-15 compounds is examined in terms of electron pairing induced by exchange of acoustic plasmons. The electronic band structure of Nb_3Sn, V_3Si, and similar materials favor transition temperatures of Tsub(c)approximately20 K. (Auth.).
Gas exchange between the plant and the environment is severely hampered when plants are submerged, leading to oxygen and energy deficits. A straightforward way to reduce these shortages of oxygen and...Full Text Available
The melting unit, consisting of a water-cooled cupola furnace, afterburner, heat exchanger, air preheater, consumes most of the supplied energy in the rockwool process. The report maps the energy flows and defines factors of merit according to thermodynam...
This year, the VGB Conference 'Steam Turbines and Operation of Steam Turbines 2008' will take place at the Deutsches Haus in Flensburg. By offering the possibility for exchanging experience, this conference aims to also ensure steam turbine operation with high availability and high efficiency in the future. The changing situation of the market and the responses on the parts of the manufacturers and the operators, as well as the responses of the entire service section to this, show that such an exchange of experience is of utmost importance. This year, the conference will focus on the following topics: - reviews - damage - further developing testing methods - monitoring steam turbines - modernising old steam turbines - new products - new developments in the condenser pipe sector. As in previous years, our Co-operation partners will present themselves at a technical exhibition which will be part of the conference. During ...
Taste cells use multiple signaling mechanisms to generate appropriate cellular responses to discrete taste stimuli. Some taste stimuli activate G protein coupled receptors (GPCRs) that cause calcium...Full Text Available
The performance of a 6 kW proton exchange membrane (PEM) electrolyzer was modeled using a semiempirical equation. Total cell voltage was represented as a sum of the Nernst voltage, activation overpotential and ohmic overpotential. A temperature and pressure dependent Nernst potential, derived from thermodynamic principles, was used to model the 20 cell PEM electrolyzer stack. The importance of including the temperature dependence of various model components is clearly demonstrated. The reversible potential without the pressure effect decreases with increasing temperature in a linear fashion. The exchange current densities at both the electrodes and the membrane conductivity were the coefficients of the semiempirical equation. An experimental system designed around a 6 kW PEM electrolyzer was used to obtain the current-voltage characteristics at different stack temperatures. A nonlinear curve fitting method was employed to determine the equation ...
Using a unique high-frequency futures dataset, we characterize the response of U.S., German and British stock, bond and foreign exchange markets to real-time U.S. macroeconomic news. We find that news produces conditional mean jumps; hence high-frequency stock, bond and exchange rate dynamics are linked to fundamentals. Equity markets, moreover, react differently to news depending on the stage of the business cycle, which explains the low correlation between stock and bond returns when averaged over the cycle. Hence our results qualify earlier work suggesting that bond markets react most strongly to macroeconomic news; in particular, when conditioning on the state of the economy, the equity and foreign exchange markets appear equally responsive. Finally, we also document important contemporaneous links across all markets and countries, even after controlling for the effects of macroeconomic news.
RasGRF1 is a Ras-guanine nucleotide exchange factor implicated in a variety of physiological processes including learning and memory and glucose homeostasis. To determine the role of RASGRF1 in aging,...Full Text Available
The following subjects are dealt with: physics of indoor air flow, flow in individual rooms, exchange of air and pollution between individual building zones and with the outside world, thermal coupling with the building shell, thermal comfort and air quality, evaluation of the ventilation. figs., tabs., refs.
This conference was held December 4--8, 1994 in Asilomar, California. The purpose of this meeting was to provide a forum for exchange of state-of-the-art information concerning the prediction of protein structure. Attention if focused on the following: comparative modeling; sequence to fold assignment; and ab initio folding.
The selective catalytic reduction of nitric oxide by methane over copper ion-exchanged natural zeolites was investigated in a packed-bed tubular reactor. The catalytic activity of Cu-N and Cu-H-N catalysts was confirmed as NO, CH{sub 4}, and O{sub 2} displayed very little reaction in the absence of any catalyst and zeolite without ion exchange was totally inactive. A maximum NO conversion of 33% at 650 C for Cu-N-66 was achieved with 2% NO and 1% CH{sub 4} and a contact time of 0.9 g s/cm{sup 3}, but the introduction of 2% O{sub 2} reduced the NO conversion to only 12%. Ion exchange for the H-form prior to copper ion exchange was essential for oxygen to promote catalytic activity over the temperature range 250--650 C, with a maximum conversion of 30% at 450 C with O{sub 2} present. The direct reduction of NO by methane was ruled out as a possible reaction pathway.
The deposition of platinum on various carbon blacks was carried out by forming active functional groups on the surface of the carbon support, and exchanging these active groups with different platinum complexes. Using H{sub 2}PtCl{sub 6} solution, an impregnation rather than an exchange takes place. However, using divalent platinum complexes [Pt(NH{sub 3}){sub 4}]{sup 2+}, a fast exchange takes place which leads to extremely small platinum particles highly dispersed on the surface of carbon black. A comparison of the catalytic activities of platinum supported on various carbon blacks was also carried out. The performances of PEFC (Polymer Electrolyte Fuel Cell) based on the process of the ion exchange are reported. (authors) 3 refs.
Antibodies of the IgM type present in rabbit anti-epiglycanin antiserum were purified by (NH4)2SO4 precipitation and by ion-exchange, affinity and gel-filtration chromatography. After papain treatment...Full Text Available
Electric cars can be recharged via charging stations, battery exchange, or induction cable lanes in asphalted roads. The users' wishes remain unexplored, so a number of technologies are competing in this sector.
Mitochondria must uptake some phospholipids from the endoplasmic reticulum (ER) for the biogenesis of their membranes. They convert one of these lipids, phosphatidylserine, to phosphatidylethanolamine,...Full Text Available
In-vitro experiments using 203Pb were performed to identify lead-binding components in human haemoglobin. Sephadex A-50 ion-exchange chromatography of haemolysate showed that different types of haemoglobin...Full Text Available
This textbook contains the following main topics: Heat conductivity, convection, condensation and evaporation, radiation heat transfer and heat exchangers. It includes the physical foundations for all these aspects and many examples. (orig.)
Total thermal resistance of ground heat exchanger (GHE) is comprised of that of the soil and inside the borehole. The thermal resistance of soil can be calculated using the linear source theory and cylindrical source theory, while that inside the borehole is more complicated due to the integrated resistance of fluid convection, and the conduction through pipe and grout. Present study evaluates heat exchange rate per depth of GHE by calculating the total thermal resistance, and compares different methods to analyze their similarities and differences for engineering applications. The effects of seven separate factors, running time, shank spacing, depth of borehole, velocity in the pipe, thermal conductivity of grout, inlet temperature and soil type, on the thermal resistance and heat exchange rate are analyzed. Experimental data from several real geothermal heat pump (GHP) applications in Shanghai are used to validate the ...
BackgroundPerfluorocarbons (PFC) are used to improve gas exchange in diseased lungs. PFC have been shown to affect various cell types. Thus, effects on alveolar type II (ATII) cells...Full Text Available
Ligand exchange of hydrated metal complexes is common in chemical and biological systems. Using the ultrafast T-jump, we examined this process, specifically the transformation of aqua cobalt (II) complexes...Full Text Available
Liquid Phase Catalytic Exchange (LPCE)- Cryogenic Distillation(CD) process was studied which could be available for an optimal tritium removal process of pressurized heavy water reactor system at Wolsung nuclear power plant in the near future. Based upon ...
The dental pulp consists of loose connective tissue encased in rigid dentinal walls. Because of its topography the tissue has low interstitial compliance and limited capacity to expand during fluid...Full Text Available
A controlled bidirectional quantum secret direct communication scheme is proposed by using a Greenberger-Horne-Zeilinger (GHZ) state. In the scheme, two users can exchange their secret messages simultaneously with a set of devices under the control of a third party. The security of the scheme is analysed and confirmed.
Carbohydrate/citrate cometabolism in Lactococcus lactis results in the formation of the flavor compound acetoin. Resting cells of strain IL1403(pFL3) rapidly consumed citrate while...Full Text Available
The aim of the present study was to describe the physicochemical characteristics of streptococcal T antigen. T protein isolated from Streptococcus pyogenes type 12 (R53/1077, Colindale) and purified...Full Text Available
A pigment-dispersing hormone (PDH) from eyestalks of the fiddler crab Uca pugilator has been purified by gel filtration, ion-exchange chromatography, partition chromatography, and reversed-phase...Full Text Available
A series of cation exchange membranes was produced by impregnating and coating both sides of a quartz web with a Nafion solution (1100 EW, 10%wt in water). Inert filler particles (SiO_2, ZrO_2 or TiO_2; 5-20%wt) were incorporated into the aqueous Nafion solution to produce robust, composite membranes. Ion-exchange capacity/equivalent weight, water take-up, thickness change on hydration and ionic and electrical conductivity were measured in 1 mol dm"-"3 sulfuric acid at 298 K. The TiO_2 filler significantly impacted on these properties, producing higher water take-up and increased conductivity. Such membranes may be beneficial for proton exchange membrane (PEM) fuel cell operation at low humidification. The PEM fuel cell performance of the composite membranes containing SiO_2 fillers was examined in a Ballard Mark 5E unit cell. While the use of composite membranes offers a cost reduction, the unit cell performance was ...
Bench-scale batch equilibration tests have been conducted with supernatants from two underground tanks at the Melton Valley Storage Tank (MVST) Facility at Oak Ridge National Laboratory (ORNL) to determine the effectiveness of selected ion exchangers in removing cesium, strontium, and technetium. Seven sorbents were evaluated for cesium removal, nine for strontium removal, and four for technetium removal. The results indicate that granular potassium cobalt hexacyanoferrate was the most effective of the exchangers evaluated for removing cesium from the supernatants. The powdered forms of sodium titanate (NaTiO) and cystalline silicotitanate (CST) were superior in removing the strontium; however, for the sorbents of suitable particle size for column use, titanium monohydrogen phosphate (TiHP {phi}), sodium titanate/polyacrylonitrile (NaTiO-PAN), and titanium monohydrogen phosphate/polyacrylonitrile (TiP-PAN) gave the best results and were about ...
Simultaneously extracted metals (SEM) and acid volatile sulfide (AVS) show the potential for toxicity on the basis of their ratio. Accordingly, the authors spiked cadmium in a range for which Cd/AVS ratios were from 0.2 to 10 in the sediment with its weight about 8 kg in each batch. Dialysis samplers with a cation ion-exchange resin (Dowex 50W-X4) collection were used in a laboratory for the determination of free cadmium concentrations in pore water of the collected sediment. When equilibrium was reached among cadmium in pore water, sediment, and ion-exchange resin, cadmium exchanged onto resin phase was regenerated with 1 N hydrochloric acid (OPTIMA grade) and determined using an atomic absorption spectrophotometer (Zeeman 5000) with a graphite furnace accessory. Cadmium determined using the dialysis sampler is considered as free cadmium which is related to the metal bioavailability toward aquatic biota. The developed ...
Crockford, G. W., Crowder, M., and Prestidge, S. P. (1972).Brit. J. industr. Med.,29, 378-386. A trace gas technique for measuring clothing microclimate...Full Text Available
The near-threshold enhancement in the ppbar invariant mass spectrum from the B^+ -> K^+ ppbar decay reported recently by the BaBar Collaboration is studied within the J\\"ulich NNbar model. We illustrate that the invariant mass dependence of the ppbar spectrum close to the threshold can be reproduced by the final state interactions. This explanation is in line with our previous analysis of the ppbar invariant mass spectrum from the J/Psi -> gamma ppbar decay measured by the BES Collaboration. We also comment on a structure found recently in the pi^+ pi^- eta' mass spectrum of the radiative J/Psi decay by the BES Collaboration. In particular we argue that one should be rather cautions in bringing this structure in connection with the enhancement found in the ppbar invariant mass spectrum or with the existence of NNbar bound states.
We address the deviations of the scaling relations of elliptical galaxies from the expectations based on the virial theorem and homology, including the "tilt" of the "fundamental plane" and the steep decline of density with mass. We show that such tilts result from dissipative major mergers once the gas fraction available for dissipation declines with progenitor mass, and derive the scaling properties of the progenitors. We use hydrodynamical simulations to quantify the effects of major mergers with different gas fractions on the structural properties of galaxies. The tilts are driven by the differential shrinkage of the effective stellar radius as a function of dissipation in the merger, while the correlated smaller enhancements in internal velocity and stellar mass keep the slope of the velocity-stellar mass relation near V \\pr M_*^{1/4}. The progenitors match a straightforward model of disc ...
The Los Alamos Nuclear Material Accounting and Safeguards System (MASS) is a near-real-time accountability system for bulk materials, discrete items, and material undergoing dynamic processing. MASS has evolved from an eighty-column card based process control system to a very sophisticated computer system. The security of the MASS computer system is provide through various access controls. There are two kinds of access control to be addressed. They are physical access control to the hardware which make up the system, and access control to the software. There are many features which provide a measure of security to the hardware that will be discussed. Access to the software is controlled by a security password. Access to various transaction activities in the system is controlled through the level of MASS user privilege. Details of MASS user privilege will be discussed.
The authors search Z{prime} bosons in dielectron events produced in p{bar p} collisions at {radical}s = 1.96 TeV, using a 0.45 fb{sup -1} dataset accumulated with the CDF II detector at the Fermilab Tevatron. To identify the Z{prime} {yields} e{sup +}e{sup -} signal, both the dielectron invariant mass distribution and the angular distribution of the electron pair are used. No evidence of a signal is found, and 95% confidence level lower limits are set on the Z{prime} mass for several models. Limits are also placed on the mass and gauge coupling of a generic Z{prime}, as well as on the contact interaction mass scales for different helicity structure scenarios.
The difficulty and unstability of the parameter estimation of mass action model for radioimmunoassay are the major obstacles to its application in routine work. A unique robust curve fitting method for the mass action model was introduced. large numbers of simulated data were generated with Monte Carlo method to compare the accuracy and robustness of the robust fitting and the least squre fitting (Marquardt method) of the mass action model. The results demonstrated that the new robusst method significantly increased the accuracy and reliability of data processing with the mass action model. It also markedly reduced the influence of outliers in the fitting of RIA data, and it was always 'convergent'. This robust method could also be applied to other mathematical models which can be transformed into high degree equations and no initial estimates are needed for curve fitting.
A study of elliptical flow is carried out for different mass asymmetries of colliding nuclei using the reactions of Formula Not Shown ( Formula Not Shown ), Formula Not Shown ( Formula Not Shown ) and Formula Not Shown ( Formula Not Shown ). The present reactions are simulated at incident energies between 50 and 250 MeV/nucleon within the framework of isospin-dependent quantum molecular dynamics model. For the present analysis, total mass of colliding pairs is kept fixed and mass asymmetry is varied between 0.3 and 0.7. The elliptical flow shows a transition from in-plane to out-of-plane in the mid rapidity region with incident energy. The transition energy is found to increase with the mass asymmetry for light charged particles. A good agreement is obtained with experimental measurements.
Abstract A large number of massive stars are known to rotate rapidly, resulting in a significant distortion and variation in surface temperature from the pole to the equator. Radiatively driven mass-loss is temperature-dependent, so rapid rotation produces a variation in the mass-loss and angular momentum loss rates across the surface of the star, which is expected to affect the evolution of rapidly rotating massive stars. In this work, we use zero-age main-sequence (ZAMS) stellar models to investigate the two-dimensional effects of rotation on stellar mass-loss, using two common prescriptions for radiatively driven mass-loss. The associated loss of angular momentum from these models is also considered. Using 2D stellar models, which give the variation in surface parameters as a function o...
Mass transfer to a wall of a horizontal rectangular channel reactor was investigated by the limiting current technique for Reynolds numbers ranging from 200 to 32000. Overall mass transfer coefficients at various mass transfer surface angles were obtained while the reactor was operated under isothermal and non-isothermal conditions. Dimensionless correlations were developed for isothermal flows from 25 to 55{sup o}C and for non-isothermal flows with applied temperature differences up to 30{sup o}C. In the laminar flow range natural convection dominated, but under turbulent conditions combined natural and forced convection prevailed. Mass transfer was approximately doubled under optimum selection of channel surface rotation, temperature gradient and flow rate. (author)
Mass transfer to a wall of a horizontal rectangular channel reactor was investigated by the limiting current technique for Reynolds numbers ranging from 200 to 32000. Overall mass transfer coefficients at various mass transfer surface angles were obtained while the reactor was operated under isothermal and non-isothermal conditions. Dimensionless correlations were developed for isothermal flows from 25 to 55"oC and for non-isothermal flows with applied temperature differences up to 30"oC. In the laminar flow range natural convection dominated, but under turbulent conditions combined natural and forced convection prevailed. Mass transfer was approximately doubled under optimum selection of channel surface rotation, temperature gradient and flow rate. (author)
Changes in mass density of amorphous Pd{sub 80}Si{sub 20} were monitored in situ during irradiation with He{sup 2+} and H{sup +} ions at temperatures below 100 K and during subsequent thermal treatment. The mass density decreased with increasing ion fluence and exponentially approached a saturation value of -1.2%, corresponding to a recombination volume of 190 atomic volumes. The initial swelling rate was 2.3 atomic volumes/displaced atom. The mass density of the irradiated material increased during subsequent thermal treatment, and the irradiation-induced decrease of the mass density recovered completely at room temperature.
An experimental and theoretical study of heat and mass transfer analogy and a comparison of that to a binary liquid mixture evaporation is presented. Common organic solvents, ethanol and n-heptane, were used to form an alcohol - hydrocarbon mixture. Studies were carried out in a horizontal rectangular channel having air flow velocities of 0.2 - 0.9 m/s. Heat transfer coefficients were measured with a copper plate resistor and mass transfer coefficients with a square pool. The heat and mass transfer analogy is presented for a system having two evaporating compounds with a fixed value of air flow and verified by measuring and comparing mass transfer coefficients for distilled water with air flow velocities of 0.2 - 0.9 m/s. An illustrative example of the use of the theory for industrial ventilation is presented. (author)
We consider typeIIA supergravity solution of D2-branes and D3-branes localized within D6-branes in the near-core region of D6-branes. With these solutions we can calculate the spectrum of the glueball mass in QCD3 and QCD4. The equation of motion describing the dilaton has the same eigenvalues and the same glueball masses in QCD3 and QCD4. Glueball mass spectrum is the same in the near core region of D6-branes of their M-theory counterpart is KK monopole. We conclude that the glueball mass spectrum is the same in QCD3 and QCD4 by considering the `near-core' limit of D6-branes of which M-theory counterpart (KK monopole background) becomes an ALE space with an $A_{N-1}$ singularity times 7 dimensional Minkowski space $M^{(6,1)}$.
This paper discusses the results of the absorption-line spectroscopy carried out with the Canada-France-Hawaii Telescope on the prototypical Sa galaxy NGC 4594 (the Sombrero galaxy). Two conclusions were derived concerning this galaxy. First, at the values of r less than 10 arcsec, there is a well-defined nuclear disk of stars which is not obviously connected to the main disk at larger radii. Second, the mass-to-light ratio, M/L(V), of the galaxy rises abruptly at r values less than 1 arcsec to values of M/L(V) greater than 50, which is at least 10 times as large as the mass-to-light ratios at r values above 2 arcsec. This implies the presence of a central dark mass of a magnitude between 10 to the 8.5th and 10 to the 9.5th solar masses. 54 references.
A new technique has been developed for the measurement of steam mass flowrate, water mass flowrate and total enthalpy of two-phase fluids produced from geothermal wells. The method involves precisely metered injection of liquid and vapor phase tracers into the two-phase production pipeline and concurrent sampling of each phase downstream of the injection point. Subsequent chemical analysis of the steam and water samples for tracer content enables the calculation of mass flowrate for each phase given the known mass injection rates of tracer. This technique has now been used extensively at the Coso geothermal project, owned and operated by California Energy Company. Initial validation of the method was performed at the Roosevelt Hot Springs geothermal project on wells producing to individual production separators equipped with orificeplate flowmeters for each phase.
The electroweak radiative correction, which turned out to be marginal within the standard electroweak model having the minimal Higgs sector in view of the present experimental information, fits well the experiment when the Higgs sector is extended to have two Higgs doublets. We predict the range where the charged and CP odd Higgs boson masses would lie, taking the two CP even neutral Higgs boson masses to be degenerate which makes the analysis in multiparameter space feasible. It is shown that the mass of neutral Higgs doublet boson can arbitrarily be large consistently with the $W$ mass, if the charged Higgs boson is present and it's mass lies in some appropriate ranges.
We have obtained radial velocities for 69 stars in the globular cluster M2 (NGC 7089). M2's rotation axis is, within sizeable uncertainties, perpendicular to the major axis determined by the flattening. The ratio of rotational to random kinetic energy agrees with that predicted from the ellipticity assuming an oblate figure and an isotropic velocity-dispersion tensor. We have fitted King-Michie models to determine M2's mass, the exponent of an assumed power-law mass function, and the anisotropy radius. The most significant sources of uncertainty in the modeling are the velocity dispersion, the distance, and the mass-luminosity relation for the cluster stars. The models favor mass functions similar to or shallower than the Salpeter initial-mass function and a moderate amount of velocity anisotropy.
We compare the metallicities of stars with radial velocity planets to the metallicity of a sample of field dwarfs. We confirm recent work indicating that the stars-with-planet sample as a whole is iron rich. However, the lowest mass stars tend to be iron poor, with several having [Fe/H]0.48) that contributes to but does not explain the mass-metallicity trend in the stars-with-planets sample. We use Monte Carlo models to show that adding an average of 6.5 Earth masses of iron to each star can explain both the mass-metallicity and the age-metallicity relations of the stars-with-planets sample. However, for at least one star, HD 38529, there is good evidence that the bulk metallicity is high. We conclude that the observed metallicities and metallicity trends are the result of the interaction of three effects; accretion of about 6 Earth masses of iron rich material, selection effects, ...
The batchwise preparation of molecular sieves for methanol conversion shows some inconsistency in catalytic stability. This is a result mainly of the change of SiO/SUB/2/Al/SUB/2O/SUB/3 in ion exchange to an H-type sieve. The dealumination during ion exchange depends upon crystal size and structural factors, which can be characterised by the cyclohexane adsorption of the raw molecular sieve. A high SiO/SUB/2/Al/SUB/2O/SUB/3 H-molecular sieve can be prepared from a molecular sieve of high adsorption capacity, this leading to a catalyst of higher stability. (4 refs.)
Six kinds of diamino-dithiol compounds are labelled with "9"9Tc"m by ligands exchange reaction. Their ligands exchange percentage is over 95%. The biodistribution of one of these compounds in mice shows 0.88% brain uptake after two minutes and 0.28% after 15 minutes respectively. Although the brain uptake is lower for this compound, it has longer retention in brain. So, the experiment results are valuable to the design of new brain imaging agent in the future.
Zirconium phosphate was one of the earliest inorganic ion-exchange suggested for removing strontium and cesium from aqueous nuclear waste. This paper studied ionic exchange to remove Cs-137 and Sr-90 by using different cationic of zirconium phosphate. In this case the parameters studied were the effect of temperature and ion concentration to percent up take and distribution coefficients. It is also conducted the study on column experiments to determine the breakthrough curves for Cs-137 and Sr-90. The result showed the potential of use of zirconium phosphate in radioactive waste treatment. (author)
Separations of metal ions on the basis of Donnan dialysis across anion-exchange membranes should be possible if the receiver electrolyte composition favors the formation of selected anionic complexes of the sample metal ions. Moreover, such a separation has the possibility of being better suited from some applications than batch or column experiments with anion-exchange resins. The above hypothesis are tested on the platinum-group metal ions, Pt(IV), Rh(III), Pd(II), Ir(III), and Ir(IV). 13 references, 4 tables.
Recovery of uranium by ion-exchange processes from impure acid leach liquors is described, which produce a concentrated and pure eluate employing 10% sulphuric acid elution. In situations where resin is loaded to 45 g/ltr or more the acid consumption at ambient temperature is less than 4 kg of H_2SO_4 per kilogram of U_3O_8. Precipitation with an alkali such as ammonia or magnesia produces a yellow cake of high purity. (author).
Late 1994, the Geothermal Heat Pump Consortium (GHPC) was launched as a non-profit collaborative effort between the United States Department of Energy, US electric utilities and the GeoExchange (geothermal heat pump) industry to make ''geothermal heat pumps'' a significant component of the HVAC industry and avoid 1.5 million metric tons of carbon equivalent per year. The goal was to create a self-sustainable GeoExchange market. This report offers a summary of some of the lessons learned and an overview of some of the programs major accomplishments.
Parameters of permanent magnets result from the combination of intrinsic properties such as saturation magnetization, magnetic exchange, and magnetocrystalline energy, as well as microstructural parameters such as phase structure, grain size, and orientation. Reduction of grain size into nanocrystalline regime (#approx# 50 nm) leads to the enhanced remanence which derives from ferromagnetic exchange coupling between highly refined grains. In this study the fundamental phenomena, quantities, and structure parameters, which define nanophase permanent magnets are presented and discussed. The theoretical considerations are confronted with experimental data for nanocrystalline Sm-Fe-N type permanent magnets. (author)
Staff exchanges, such as the one described in this report, are intended to facilitate communication and collaboration among scientists and engineers at DOE laboratories, in US industry, and academia. During the past 5 years, PNL has developed prototype instrumentation to automate the data collection required for electrochemical determination of corrosion rates and behavior of materials in various electrically conductive environments. The last version is labeled the Sentry 100 prototype corrosion data scanner. Applications include these in the pulp and paper industry and at hazardous waste sites.
The report is divided into three sections. The first section contains a general introduction to ion exchange resins used in various processes, the second section describes characteristic properties of the polymer materials and the inter relation between them. This will, in turn, be useful to interpret the data obtained from the various tests carried out on the resins in the laboratory. In the third section of the report, are given the details of each method used for a particular test to be carried out on a routine basis. Each method describes the principle involved, the reagents and apparatus used in the experiment, the actual procedure and calculations and recording of the data. 3 refs. (author).
A comprehensive presentation is made of state-of-the-art configurations and design methodologies for heat transfer devices applicable to industrial processes, automotive systems, air conditioning/refrigeration, cryogenics, and petrochemicals refining. Attention is given to topics in heat exchanger mechanical design, single-phase convection processes, thermal design, two-phase exchanger thermal design, heat-transfer augmentation, and rheological effects. Computerized analysis and design methodologies are presented for the range of heat transfer systems, as well as advanced methods for optimization and performance projection.
A laser-induced plasma of alkali atoms was studied with a view to efficient recovery of isotope ions, with small charge exchange losses. The electron temperature was measured by the double-probe method for several kinds of excitation schemes, which gave the relationship between temperature and the energy given to ions by laser photons. A charge exchange process between lithium isotopes was also studied in an electromagnetic field. It was shown that optimum electrostatic and magnetic field strength exist which maximise the 'separative power'.
This report summarizes the electricity exchanges between the US and Mexico and Canada during calendar year 1983. The construction, operation and maintenance of any electric transmission facility which crosses an international border of the United States requires a Presidential Permit. These permits have been granted by the Department of Energy (DOE) since its formation in 1977. Between 1953 and 1977, these permits were issued by the former Federal Power Commission. Prior to 1953, they were issued by the President of the United States. Presidential Permits require that an annual report be filed by the permit holder detailing all transactions with the foreign country.
The high temperature gas-cooled test reactor HTR-10 achieved the first criticality in last December in Institute of Nuclear Energy Technology of Tsinghua University in Beijing. Fuji Electric and Nissho Iwai have a cooperative information exchange agreement on the commercialization of the HTGRs with INET, and held an information exchange meeting in last March in INET. INET has started a study on the modification of the HTR-10 to couple with gas turbine system and a pre-feasibility study on the commercial HTGR under the cooperation with China State Power Company. The experiences and abilities of INET in the field of the HTGR and the aggressive plan for commercialization of the HTGR in China are summarized and discussed. (author)
I formulate a model in which money coexists with equity shares on a risky aggregate endowment. Agents can use equity as a means of payment, so shocks to equity prices translate into aggregate liquidity shocks that disrupt the mechanism of exchange. I characterize a family of optimal monetary policies and find that the resulting equity prices are independent of monetary considerations. I also study a perturbation of the family of optimal policies that targets a positive constant nominal interest rate and find that in this case the real equity return includes a liquidity return that depends on monetary considerations.
Theoretical prediction of nuclear masses is analyzed as a pattern recognition problem on the N-Z plane. A global pattern is observed by plotting the differences between measured masses and Liquid Drop Model (LDM) predictions. After unfolding the data by removing the smooth LDM mass contributions, the remaining microscopic effects have proved difficult to model, although they display a striking pattern. These deviations carry information related to shell closures, nuc]ear deformation and the residual nuclear interactions. In the present work the more than 2000 known nuclear masses are studied as an array in the N-Z plane viewed through a mask, behind which the approximately 7000 unknown unstable nuclei that can exist between the proton and neutron drip lines are hidden. We show here that employing a Fourier transform deconvolution method these by masses can be predicted with similar ...
Theoretical prediction of nuclear masses is analyzed as a pattern recognition problem on the N-Z plane. A global pattern is observed by plotting the differences between measured masses and Liquid Drop Model (LDM) predictions. After unfolding the data by removing the smooth LDM mass contributions, the remaining microscopic effects have proved difficult to model, although they display a striking pattern. These deviations carry information related to shell closures, nuc]ear deformation and the residual nuclear interactions. In the present work the more than 2000 known nuclear masses are studied as an array in the N-Z plane viewed through a mask, behind which the approximately 7000 unknown unstable nuclei that can exist between the proton and neutron drip lines are hidden. We show here that employing a Fourier transform deconvolution method these by masses can be predicted with similar ...
We calculate the masses of the resonances D{sub s0}{sup *}(2317) and D{sub s1}(2460) as well as their bottom partners as bound states of a kaon and a D{sup (*)} - and B{sup (*)} -meson, respectively, in unitarized chiral perturbation theory at next-to-leading order. After fixing the parameters in the D{sub s0}{sup *}(2317) channel, the calculated mass for the D{sub s1}(2460) is found in excellent agreement with experiment. The masses for the analogous states with a bottom quark are predicted to be M{sub B{sup *}{sub s0}}=(5696{+-}40) MeV and M{sub B{sub s1}}=(5742{+-}40) MeV in reasonable agreement with previous analyses. In particular, we predict M{sub B{sub s1}}-M{sub B{sub s0}}{sup *}=46{+-}1 MeV. We also explore the dependence of the states on the pion and kaon masses. We argue that the kaon mass dependence of a kaonic bound state should be almost linear with slope about unity. ...
Crystalline Pd_9Si_2 possesses an orthorhombic structure (Pnma) that is characterized by augmented triangular prismatic coordination of the silicon atoms such as that which occurs in several metal-rich transition-metal silicides. Recent neutron diffraction results for deuterium solution in this crystalline phase have indicated that deuterium occupies only one type of interstice, i.e., a Pd-defined pyramidal site in a four-fold position situated on a quadrilateral face of an empty triangular prism. The vibrational dynamics of both H and D located at this site were investigated by neutron vibrational spectroscopy. The low-temperature density of states (DOS) of H in Pd_9Si_2H_0_._2_5 indicates three well-defined optic vibrations located at 49.4, 67.2 and 75.5 meV. The lowest-energy feature is assigned to the normal-mode vibration perpendicular to the pyramidal base and the two higher-energy features are assigned to the two orthogonal normal-mode vibrations parallel to this base. The ...
Cross sections for some electro- and photoinduced spallation reactions on {sup 27}Al and {sup 51}V are measured in the energy region 130 MeV to 580 MeV with the activation method. Comparisons are made with calculations based on the Dalitz formalism for virtual photon spectra, and Monte Carlo calculations based on a cascade evaporation model, respectively. By use of Bremsstrahlung with end-point energies from threshold to 750 MeV, the yields for photo- production of{pi}{sup -}leading to ground and isomeric states in {sup 197}Hg are measured with the activation method. The activity from the Hg-isotopes were measured after a chemical separation of Hg from the target material. The yields and isomeric ratios are compared with impulse approximation calculations. For the photoproduction of {sup 195m}Hg and {sup 192}Hg from {sup 197}Au, the yields were measured. The experimental mean cross sections are compared with data from other experiments and with cascade evaporation calculations. Cross ...
Penning trap mass spectrometry is presented as a complementary tool to nuclear spectroscopy experiments for the study of nuclear structure in the vicinity of N=40, Z=28. High-precision mass measurements of the "6"3"-"6"6Fe and "6"4"-"6"7Co isotopes have been carried out with the Low Energy Beam and Ion Trap (LEBIT) Penning trap mass spectrometer. The newly obtained mass values for "6"6Fe and "6"7Co are presented, together with the previously reported LEBIT mass measurements in this region. In the case of "6"5Fe the existence of a new isomer is reported, and an isomer recently discovered by decay spectroscopy in "6"7Co is confirmed. Relative mass uncertainties as low as 4x10"-"8 are obtained. All mass values are found to be in good agreement with previous experimental results with the exception of "6"4Co, where a 5#sigma# deviation is ...
The object and the purpose of the present work was to develop, to assemble and to start running a new TOF (time of flight) mass spectrometer for imaging SNMS analytic which is optimized for the analysis of highly molecular secondary ions. The most important purpose was the characterization of the TOF mass spectrometer. The obtained mass spectra of indium, tantalum and silver clusters reflect the excellent properties of the TOF mass spectrometer for the detection of large clusters with good detection efficiency up to masses of 16000 amu. The possibility of the deflection of selected saturated atom and cluster peaks serves for further improvement of the detection efficiency for large molecules. The accessible mass resolution was determined to be of the order of m/{delta}m=1000 in the high mass region. Numerous measurements were carried out to ...
The rate of the oxygen-exchange reaction in an aqueous solution of a heterocyclic oxygen compound, 2,4,6-trimethylpyrylium perchlorate, was quantitated. The /sup 18/O isotope effect in /sup 13/C NMR spectroscopy affords a direct, continuous, and relatively simple analysis of the reaction and was used to obtain data on the incorporation of /sup 18/O from solvent H/sub 2//sup 18/O into the pyrylium salt. Due to the low solubility of this salt in aqueous solutions, 2,4,6-trimethyl(2-/sup 13/C)pyrylium perchlorate and 2,4,6-trimethyl(2,6-/sup 13/C/sub 2/)pyrylium perchlorate were synthesized to facilitate the acquisition of the data on an NTC-200 spectrometer operating at 50.31 MHz. Upon incorporation of /sup 18/O into the pyrylium salt, the /sup 13/C NMR signal of the directly bonded carbon atom is shifted upfield 0.038 ppm. A /sup 13/C isotope effect is also detected in the doubly /sup 13/C-enriched pyrylium salt where the /sup 13/C NMR signal for /sup 13/C-O-/sup ...
We consider the most general supersymmetric model with minimal particle content and an additional discrete Z_3 symmetry (instead of R-parity), which allows lepton number violating terms and results in non-zero Majorana neutrino masses. We investigate whether the currently measured values for lepton masses and mixing can be reproduced. We set up a framework in which Lagrangian parameters can be initialised without recourse to assumptions concerning trilinear or bilinear superpotential terms, CP-conservation or intergenerational mixing and analyse in detail the one loop corrections to the neutrino masses. We present scenarios in which the experimental data are reproduced and show the effect varying lepton number violating couplings has on the predicted atmospheric and solar mass^2 differences. We find that with bilinear lepton number violating couplings in the superpotential of the order 1 MeV the ...
The recent development of matrix-assisted UV laser desorption (LD) mass spectrometry has made possible the ionization and detection of extremely large molecules (with molecular weights exceeding 100,000 Daltons). This technique has generated enormous interest in the biological community for the direct examination of large peptides and oligonucleotides. Although this matrix-assisted ionization method has been developed and used almost exclusively with time-of-flight (TOF) mass spectrometers, research is currently in progress to demonstrate this technique with trapped ion mass spectrometers, such as Fourier transform ion cyclotron resonance mass spectrometry (FTMS). The potential capabilities of FTMS for wide mass range, high resolution measurement, and ion trapping experiments suggest that this instrumental technique should be useful for the detailed structural characterization of ...
The properties of the mass-metallicity relation among dwarf spheroidal galaxies are discussed in terms of a model which assumes that the internal chemical evolution of the dwarf spheroidals was promoted by supernova activity. The model can be used to explain the observed dwarf spheroidal mass-metallicity relation assuming the present mass of these systems M sub s is proportional to their initial masses M as M sub s varies according to a power-law index of exp 7/4. It is inferred from the power-law dependence of M on the proto-cloud radius that the most massive dwarf spheroids were formed from the densest clouds. The observed slope of the mass-metallicity relation for dwarf spheroidal galaxies is found to be significantly different from theoretical estimates of this slope for elliptical galaxies. It is suggested that the difference may imply that spheroidal dwarfs and elliptical ...
Mass density of a composite is generally taken as the volume-averaged value of components' densities. Moreover, the same volume-averaged mass density is usually used to calculate the wave speed in the long-wavelength limit, i.e., where the wavelength is much larger than the size of the inhomogeneities. In this paper, we show via rigorous derivation that the dynamic mass density used in the calculation of (long-wavelength) wave speed can differ significantly from the static volume-averaged value. This recognition is shown to yield an excellent account of some recent experimental data, as well as to make possible the realization of acoustic metamaterials. Physical reason for the difference between two mass densities is attributed to the relative motion between the components. That is, the implicit assumption-that all components in a composite must move uniformly in the long-wavelength limit-can ...
We study the evolution of the cold gas content of galaxies by splitting the interstellar medium into its atomic and molecular hydrogen components, using the galaxy formation model GALFORM in the LCDM framework. We calculate the molecular-to-atomic hydrogen mass ratio, H2/HI, in each galaxy using two different approaches; the pressure-based empirical relation of Blitz & Rosolowsky and the theoretical model of Krumholz, McKeee & Tumlinson, and apply them to consistently calculate the star formation rates of galaxies. We find that the model based on the Blitz & Rosolowsky law predicts an HI mass function, CO(1-0) luminosity function, correlations between the H2/HI ratio and stellar and cold gas mass, and infrared-CO luminosity relation in good agreement with local and high redshift observations. The HI mass function evolves weakly with redshift, with the number density of high ...
We have developed a new method for calculating common envelope (CE) events based on explicit consideration of the donor star's structural response to adiabatic mass loss. In contrast to existing CE prescriptions, which specify a priori the donor's remnant mass, we determine this quantity self-consistently and find that it depends on binary and CE parameters. This aspect of our model is particularly important to realistic modeling for upper main-sequence star donors without strongly degenerate cores (and hence without a clear core/envelope boundary). We illustrate the central features of our method by considering CE events involving 10 M_s_u_n donors on or before their red giant branch. For such donors, the remnant core mass can be as much as 30% larger than the star's He-core mass. Applied across a population of such binaries, our methodology results in a significantly broader remnant ...
Most of the presently identified exoplanets have masses similar to that of Jupiter and therefore are assumed to be gaseous objects. With the ever-increasing interest in discovering lower-mass planets, several of the so-called super-Earths (i.e., with masses in the interval 1 M_earth < M < 10 M_earth), which are predicted to be rocky, have already been found. Here we report the possible discovery of a planet around the M-type star GJ 436 with a minimum mass of 4.8+/-0.6 M_earth and a true mass of ~5 M_earth, which makes it the least massive planet around a main-sequence star found to date. In contrast with other discoveries, the planet is identified from its perturbations on an inner Neptune-mass transiting planet (GJ 436b), by pumping eccentricity and producing secular variations in the orbital inclination. Analysis of published radial velocity ...
We consider non-relativistic systems in quantum mechanics interacting through the Coulomb potential, and discuss the existence of bound states which are stable against spontaneous dissociation into smaller atoms or ions. We review the studies that have been made of specific mass configurations and also the properties of the domain of stability in the space of masses or inverse masses. These rigorous results are supplemented by numerical investigations using accurate variational methods. A section is devoted to systems of three arbitrary charges and another to molecules in a world with two space-dimensions.
Mass distributions of fragments in the low-energy fission of nuclei from "1"8"7Ir to "2"1"3At have been analysed. This analysis has shown that shell effects in symmetric-mode fragment mass yields from the fission of pre-actinide nuclei could be described if one assumes the existence of two strongly deformed neutron shells in the arising fragments with neutron numbers N_1#approx#52 and N_2#approx#68. A new method has been proposed for quantitatively describing the mass distributions of the symmetric fission mode for pre-actinides with A#approx#180-220. (orig.)
Investigations were conducted at Los Alamos National Laboratory to quantify the extent of migration of depleted uranium away from firing sites. Extensive sampling of air particles, soil, sediment, and water was conducted to establish the magnitude of uranium contamination throughout one watershed. The uranium source term was estimated, and mass balance calculations were performed to compare the percentage of migrated uranium with original expenditures. Mass balance calculations can be powerful in identification of the extent of waste migration and used as an aid in planning future waste investigations.
Geochemical model is a kind of concept model which describes geochemical processes by means of chemical reaction equations and mathematical formula, and the software based on the concept model are called geochemical modeling code. Geochemical modeling codes can be divided into three categories: mass equilibrium, mass transfer and mass transport code. The major functions of geochemical codes include the calculation of forms of occurrence of elements, the prediction of direction of various geochemical reaction, the dissolution and precipitation of elements, the pH and Eh value, the rate and path of geochemical reaction in aqueous solution.
By using a model independent Monte Carlo approach, we study the possible structure of charged and neutral lepton mass matrices, under the assumption of an U(2) horizontal symmetry (additional to the usual Standard Model ones) involving the light fermion generations. We assume the most general Majorana mass matrix for neutrinos. We update the results of our previous similar study, by inserting in the analysis the recent KamLAND data, that contributed to find a final solution to the Solar neutrino problem. The introduction of the new experimental data reduce the allowed regions in the nine dimensional space parameters, and show that our procedure gives stable solutions.
The masses of 16 neutron-rich nuclei in the mass range from 35 to 45 have been measured using a direct time of flight technique following the fragmentation of a {sup 48}Ca beam at 60 MeV/nucleon. The masses of {sup 35,36}Mg, {sup 38}Al, {sup 39,40}Si, {sup 42,43}P and {sup 43,44}S are reported for the first time. Preliminary analysis shows that the N=28 shell closure persists, even if weakened by the large neutron excess.
The masses of 16 neutron-rich nuclei in the mass range from 35 to 45 have been measured using a direct time of flight technique following the fragmentation of a "4"8Ca beam at 60 MeV/nucleon. The masses of "3"5","3"6Mg, "3"8Al, "3"9","4"0Si, "4"2","4"3P and "4"3","4"4S are reported for the first time. Preliminary analysis shows that the N=28 shell closure persists, even if weakened by the large neutron excess.
This paper discusses the mass spectrometric system that has been developed at the ICPP (Idaho Chemical Processing Plant) to meet the multiple constraints of U accountability, high sample load, and plant process control. The measurement system must produce high-quality accountability results while maintaining high sample throughput and reasonable turnaround time. The mass spectrometric system that has evolved to meet these demands includes extensive operator training, routine quality control checks, and continuing review of performance. 7 refs.
We present the efficient technique to extract the signal of the intermediate mass Higgs boson from the backgrounds at future {gamma}{gamma} colliders. For a clear Higgs detection, it is important to fit the original electron accelerator energy depending on the Higgs mass, to set the polarization of the photon beams and to apply the efficient b quark tagging method. we demonstrate the extraction of information of Higgs parameters and the new physics from the observable physical quantities. It is clearly shown that a future {gamma}{gamma} collider will have a rich potential for study on the new physics, as well as the Higgs physics. (author).
We present the efficient technique to extract the signal of the intermediate mass Higgs boson from the backgrounds at future #gamma##gamma# colliders. For a clear Higgs detection, it is important to fit the original electron accelerator energy depending on the Higgs mass, to set the polarization of the photon beams and to apply the efficient b quark tagging method. we demonstrate the extraction of information of Higgs parameters and the new physics from the observable physical quantities. It is clearly shown that a future #gamma##gamma# collider will have a rich potential for study on the new physics, as well as the Higgs physics. (author).
We discuss the inclusive production of D{sup *{+-}} mesons in {gamma}p collisions at DESY HERA, based on a calculation at next-to-leading order in the general-mass variable-flavor-number scheme. In this approach, MS subtraction is applied in such a way that large logarithmic corrections are resummed in universal parton distribution and fragmentation functions and finite mass terms are taken into account. We present detailed numerical results for a comparison with data obtained at HERA and discuss various sources of theoretical uncertainties. (orig.)
Analytical solutions are derived for a flow in a semi-infinite vertical porous medium with heat and mass transfer. When the temperature and mass concentration are uniform a constant pressure is possible and sustains a fully developed flow. Thereafter there is a small perturbation on the wall temperature and concentration and the subsequent two-dimensional problem is tackled for a large Prandtl number, free convection parameters and small Reynolds number. The heat transfer rate at the wall is discussed quantitatively. (author). 4 refs.
In order to improve the capacity and service life of cathodes, the effect of carboxy-methyl cellulose, soot, silica gel and fibres was examined. Structural tests and electrical and electro-chemical measurements are used for this. The additives can affect crystallization in the manufacturing stage of the electrodes and can increase the storage capacity for water and the electronic conductivity. They act to stabilize the mass in cyclic operation. Soot additive has little effect on the properties of the electrode, but the other substances increase the service life or the use of the mass. (LU).
We show that specially designed two-dimensional arrangements of full elastic cylinders embedded in a nonviscous fluid or gas define (in the homogenization limit) a new class of acoustic metamaterials characterized by a dynamical effective mass density that is anisotropic. Here, analytic expressions for the dynamical mass density and the effective sound velocity tensors are derived in the long wavelength limit. Both show an explicit dependence on the lattice filling fraction, the elastic properties of cylinders relative to the background, their positions in the unit cell, and their multiple scattering interactions. Several examples of these metamaterials are reported and discussed.
The humidification?dehumidification process is an interesting technique that has been adapted for water desalination. Previous works experimentally investigated desalination processes in the shell and tube columns, where the humidification and dehumidification were thermally coupled and simultaneously performed at the tube and shell sides, respectively. In this work, a comprehensive steady-state mathematical model was developed for such a humidification?dehumidification desalination process by taking into account the heat and mass balances on both sides of the desalting column, the mass transfer rate at the humidification side, and the heat transfer rate between the dehumidification side and humidification side. Meanwhile, the mass transfer coefficient at the humidification side and the to...
Following the Chernobyl nuclear disaster, a considerable amount of effort and resources were allocated worldwide to designing and developing coherent and comprehensive decision support systems for nuclear or radiological emergency management. They range from simple radiological consequence assessment tools to more advanced systems, incorporating the assessment of countermeasures and their effectiveness. Furthermore, many of these systems have been tailored to answer to national emergency preparedness requirements and in some cases such as the R.O.D.O.S. and A.R.G.O.S. systems they have been successfully deployed in a number of countries. Thus, computer based decision support systems for nuclear emergencies are nowadays a reality in Europe, the US and Japan; however, there was a lack of an adequate information and data exchange mechanism that enabled them to function properly and serve the purpose that triggered their development. Within the EURATOM 5. Framework ...
Present and potential future changes to the global environment have important implications for marine pollution and for the air-sea exchange of both anthropogenic and natural substances. This report addresses three issues related to the potential impact of global change on the air-sea exchange of chemicals: Global change and the air-sea transfer of the nutrients nitrogen and iron. Global change and the air-sea exchange of gases. Oceanic responses to radiative and oxidative changes in the atmosphere. The deposition of atmospheric anthropogenic nitrogen has probably increased biological productivity in coastal regions along many continental margins. Atmospheric deposition of new nitrogen may also have increased productivity somewhat in mid-ocean regions. The projected future increases of nitrogen oxide emissions from Asia, Africa and South America will provide significant increases in the rate of deposition of oxidized ...
Nitric acid leaching from the weak base anion (WBA) exchanger had been evaluated and based on this a 5% mixture of nitric acid loaded weak base anion exchanger with fresh weak base anion exchanger (NLWBA) at the bottom of the ion exchange column has been devised to maintain an outlet pH in the range of 5.0 to 5.5 during Gd removal from the moderator system of TAPP - 3 and 4. A three layered bed had been constituted wherein strong acid cation (SAC) exchanger is placed as the top layer while a mixed bed of SAC and WBA or pure WBA is used as the middle layer and the 5% NLWBA was used as the bottom most layer. This bed configuration would result in an iso-pH regime in the moderator system during the Gd removal along with quantitative removal of Gd. Two three-layer bed columns were prepared at TAPS - 3 and 4 in July 07. The resin was loaded in batches and after preparing the column, the ...
Active Process Water (APW) system is provided as a unitized system in TAPP-3 and 4. Maintenance on APW system requires shutdown of this system. As shut down heat exchangers are fed by APW system; during APW system shutdown cold shutdown state cannot be maintained. Therefore safety analysis is done to optimize the duration of reactor shutdown (which means low decay heat) after which APW shutdown can be taken with minimum water supply to the shutdown heat exchangers. Based on this analysis, it is proposed in technical specification that APW system shutdown can be taken after 7 days of reactor shutdown with shutdown heat exchangers supplied with about 20 % of normal APW flow. With this configuration, PHTS, moderator, end shield, calandria vault water temperature can be maintained within limits. A design provision is made at TAPP-3 and 4 to interconnect APW system of both units in such a way that one unit in addition to its own ...
In relation to coal gasification and combustion under high pressure as highly efficient coal utilization, the effect of total pressure and sintering on the SO2 capture ability of Ca-ion exchanged coal and other desulfurizing agents were studied. In experiment, specimens were filled into a small pressurized reactor to heat them under high-pressure N2 atmosphere. After the completion of combustion reaction of char at 850{degree}C, SO2, CO2 and CO gases were measured at an outlet while flowing SO2/N2. As the experimental result, all of the S content in Ca-ion exchanged coal was not absorbed by Ca content in coal during pyrolysis and combustion, resulting in discharge of 36% of the S content. Since Ca-ion exchanged coal is fast in combustion reaction, most of the S content was desulfurized by coal ash. The ash content yielded from Ca-ion exchanged coal was more excellent in SO2 capture ability than ...
We have successfully incorporated high surface area particles of titanate ion exchange materials (monosodium titanate and crystalline silicotitanate) with acceptable particle size distribution into porous and inert support membrane fibrils consisting of polytetrafluoroethylene (Teflon(reg_sign)), polyethylene and cellulose materials. The resulting membrane sheets, under laboratory conditions, were used to evaluate the removal of surrogate radioactive materials for cesium-137 and strontium-90 from high caustic nuclear waste simulants. These membrane supports met the nominal requirement for nonchemical interaction with the embedded ion exchange materials and were porous enough to allow sufficient liquid flow. Some of this 47-mm size stamped out prototype titanium impregnated ion exchange membrane discs was found to remove more than 96% of dissolved cesium-133 and strontium-88 from a caustic nuclear waste salt simulants. Since ...
Chiral symmetry in QCD can be simultaneously in Wigner and Goldstone modes, depending on the part of the spectrum examined. The transition regime between both, exploiting for example the onset of parity doubling in the high baryon spectrum, can be used to probe the running quark mass in the mid-IR power-law regime. In passing we also argue that three-quark states naturally group into same-flavor quartets, split into two parity doublets, all splittings decreasing high in the spectrum. We propose that a measurement of masses of high-partial wave Delta* resonances should be sufficient to unambiguously establish the approximate degeneracy and see the quark mass running. We test these concepts with the first computation of the spectrum of high-J excited baryons in a chiral-invariant quark model.
Chest computed tomography (CT) was valuable in detecting extrinsic tracheal compression by mediastinal masses in two pediatric patients. This prompted an independent evaluation by CT of 14 children with masses involving the middle mediastinum and possible intrathoracic tracheal narrowing. Computer programs permit precise calculation of tracheal cross-sectional areas. Any apparent decrease in tracheal area may be compared with CT-derived data in normal children. Chest CT not only demonstrates the presence of extrinsic airway compression in pediatric patients with mediastinal masses, but also is capable of precisely measuring the extent of this narrowing. This method identifies children at potential risk for respiratory compromise and may aid in subsequent therapy.
We investigate the solar neutrino problem in the scenario of three generation neutrino oscillation hypothesis, taking into account other phenomenological constraints to the neutrino mixing and mass parameters.
The Bragg-curve detector of the parallel plate ionization chamber type generates a signal that is a distorted replica of the original Bragg-curve. In result of this distortion, the signal peak height is not only a function of the atomic number of the heavy ion, as it is often stated, but also of the particle mass. This mass effect was studied with the aid of computer simulation, and it was found to be dependent on the Frisch grid to anode gap width and on the detector gas. The charge resolution of the detector is affected very significantly by this mass dependence of the signal peak height. Therefore, a careful selection of the detector gas and the grid to anode gap width is necessary, if good charge resolution over a wide range of heavy ions is required. (orig.).
A theory for the mass transfer process was developed. It was assumed that the largest convective motions in the flow control the rate of mass transfer. Measurements of mass transfer coefficients for the absorption of oxygen by water films were made for concurrent flows in a horizontal rectangular channel, and for concurrent and free-falling downflow in a one-inch pipe. The measured values of the Sherwood number for concurrent flows were up to three times as great as would be predicted from this relation. This increase in Sherwood number was correlated with a dimensionless group similar to a Martinelli parameter which is characteristic of two phase flows. An explanation for this effect is given in terms of the way that the scales of the convective motions are related to bulk flow parameters.
IntroductionThe outbreak of cholera in Zimbabwe intensified interest in the control and prevention of cholera. While there is agreement that safe water, sanitation, and personal...Full Text Available
15 to 75% of the gun barrel diameter. Similarly, model masses typically vary from 0.01 to 100 .... taining acceptable levels of gun barrel erosion. The ...
The Nobel lecture of Chandrasekhar is printed in which he describes the basic processes that determine the life history of a star with particular emphasis on the roles of stellar mass and radiation pressure. (AIP)
We report a 55-year-old woman with coccydynia due to a sacral mass. The histological diagnosis was haemangioma. The MRI findings and the unusual location of this lesion are discussed. (orig.)
We study the renormalization group running of the tri-bimaximal mixing predicted by the two typical $S_4$ flavor models at leading order. Although the textures of the mass matrices are completely different, the evolution of neutrino mass and mixing parameters is found to display approximately the same pattern. For both normal hierarchy and inverted hierarchy spectrum, the quantum corrections to both atmospheric and reactor neutrino mixing angles are so small that can be neglected. The evolution of solar mixing angle $\\theta_{12}$ depends on $\\tan\\beta$ and mass spectrum, the deviation from its tri-bimaximal value could be large. Taking into account the renormalization group running effect, the neutrino spectrum is constrained by experimental data on $\\theta_{12}$ and the inverted hierarchy spectrum is disfavored for large $\\tan\\beta$. The evolution of light neutrino masses is approximately ...
sive star evolution based on our new calculations of this pulsational instability, where the initial mass of SNe progenitors increases according to the ...
... mass of gray gas by thermal radiation; An experimental study of the turbulent wake behind a cone at M = 5; Heat transfer augmentation by steady ...
We complete the effective potential calculation of the two-loop, top/bottom Yukawa corrections to the Higgs boson masses in the Minimal Supersymmetric Standard Model, by computing the O(at^2 + at*ab + ab^2) contributions for arbitrary values of the bottom Yukawa coupling. We also compute the corrections to the minimization conditions of the effective potential at the same perturbative order. Our results extend the existing O(at^2) calculation, and are relevant in regions of the parameter space corresponding to tan(beta) >> 1. We extend to the Yukawa corrections a convenient renormalization scheme, previously proposed for the O(ab*as) corrections, that avoids unphysically large threshold effects associated with the bottom mass and absorbs the bulk of the corrections into the one-loop expression. For large values of tan(beta), the new contributions can account for a variation of several GeV in the lightest Higgs boson ...
The disrupted magnetic braking theory for the period gap of cataclysmic variable systems is used to study the binary evolution of low-mass main-sequence-like stars with white dwarf companions. The model is able to reproduce the observed location and width of the gap provided that the average mass transfer rates above the upper edge of the gap are greater than about 1.9 x 10 to the -9th solar masses/yr. For the case of angular momentum loss by magnetic braking, the slope of the mass transfer rate with respect to orbital period is shown to range from 3.4 to 3.7. For the evolutionary sequences considered, the He-3 abundance at the surface of the secondary exceeds 0.0015 after the complete mixing phase, resulting in modifications in the nuclear burning development of nova explosions. 31 refs.
The available nuclear structure information for all nuclei with mass number A=242 is presented. Various decay and reaction data are evaluated. Adopted data, levels, spin and parity assignments are given.
Detailed level and decay schemes are presented for the nuclei of the A = 101 mass chain. The level properties obtained from decay and reaction experiments are shown in the drawings. Experimental methods, references, and comments are given in the text.
Detailed level and decay schemes are presented for the nuclei of the A = 101 mass chain. The level properties obtained from decay and reaction experiments are shown in the drawings. Experimental methods, references, and comments are given in the text.
NEWTON's first law prohibits the coupling of free tachyons to ordinary matter, if it is interpreted as selection rule interdicting emission without change of the rest-mass of the emitting system.
... and regional land, sea, air, and space-based systems, and ... means of delivery of weapons where such ... a separable and divisible part of the weapon. ...
coupled heat/mass transfer Stefan problem. Taking the diffusion coefficient of Bi as a free parameter, the best fit was observed for the published value, ...
The Bragg-curve detector of the parallel plate ionization chamber type generates a signal that is a distorted replica of the original Bragg-curve. In result of this distortion, the signal peak height is not only a function of the atomic number of the heavy ion, as it is often stated, but also of the particle mass. This mass effect was studied with the aid of computer simulation, and it was found to be dependent on the Frisch grid to anode gap width and on the detector gas. The charge resolution of the detector is affected very significantly by this mass dependence of the signal peak height. Therefore, a careful selection of the detector gas and the grid to anode gap width is necessary, if good charge resolution over a wide range of heavy ions is required.
Commercial rolled magnesium sheets of alloys AZ31 (Mg-3 mass%Al-1 mass%Zn) and ZE10 (Mg-1 mass% Zn-<1 mass% Rare Earths) in O-temper condition were used for blanking experiments near room temperature. A serrated fracture surface can be observed in case of AZ31 but not in case of ZE10. During the shearing process of the AZ31 sheet, many micro cracks parallel to the sheet plane are generated in the shearing zone. These micro cracks lead to the formation of loose particles during the shearing operation, which interfere with further processing of the part and incur additional costs by increasing the scrap rate. It is found that the strong basal texture of this alloy is an important reason for the generation of such serrated cracks. In this paper a new method of selective texture modification i...
The UW-Penning Trap Mass Spectrometer (PTMs) is ideally suited for high precision measurements of atomic masses throughout the periodic table upon using highly-stripped ions. However, at the present time, this device has been applied extensively to the light elements ("1H, "2H, "3H, "3He, "4He, "1"2C, "1"3C, "1"4N, "1"6O) due to their fundamental importance. Atomic masses follow immediately from a comparison with some multiply-charged carbon ion, after correcting for the lost electrons and their corresponding binding energies. For instance, the most recent C"5"+/C"6"+ comparison yielded a discrepancy of -0.30(33) ppb, limited only by the magnetic field instability for a 40-h run. The initial emphasis on hydrogen has now produced a 1-ppb value for the proton's atomic mass and similar work with deuterium has yielded a 2.5-ppb value for the neutron's atomic mass. However, the most ...
Development of the Technology and Control of Electron-Beam Welding Procedure and Production of Full Scale Sector of Endcap CMS Hadron Calorimeter. Preparation for Mass Production.
Many methods have been proposed for the determination of the corrosion current density from polarization curves; the two most commonly used ones are the three-point method and the curve-fitting method. The basis of these methods is a polarization equation that was derived for the complete absence of mass-transport effect or considers the cathodic partial reaction to be under complete mass-transport control. The mixed-control case has been much less investigated, even though this case may quite frequently reflect practical situations. A completely generalized polarization equation is proposed that can be used as a basis for curve-fitting data evaluation under any conditions. This equation was used to determine the error caused by the neglect of mass-transport effect in conventional data evaluation.
... assets, particularly against ballistic missiles with weapons of mass ... more con- ventional missile and gun weapon systems. ... Similarly, space-based ...
BACKGROUND: Cuba's response to the human immunodeficiency virus (HIV) epidemic has been to conduct mass testing of the population to ascertain seroprevalence, to enforce mandatory relative quarantine...Full Text Available
This is the first text and reference book to be devoted completely to the very important and timely subject of heat transfer augmentation. This book is of equal appeal to both researchers and designers of heat transfer equipment.
Accelerator Mass Spectrometry (AMS) is the analytical technique of choice for the detection of long-lived radionuclides which cannot be practically analysed with decay counting or conventional mass spectrometry. The main use of AMS has been in the analysis of radiocarbon and other cosmogenic radionuclides for archaeological, geological and environmental applications. In addition, AMS has been recently applied in biomedicine to study exposure of human tissues to chemicals and biomolecules at attomole levels. There is also a world-wide effort to analyse rare nuclides of heavier masses, such as long-lived actinides, with important applications in safeguards and nuclear waste disposal. The use of AMS is limited by the expensive accelerator technology required and there are several attempts to develop smaller and cheaper AMS spectrometers. 5 refs.
Apr 23, 2009 ... Wolf-Rayet stars have over 20 times the mass of the Sun and are thought to be in a brief, pre-supernova phase of massive star evolution. ...
We describe a method of determining the system parameters in non-eclipsing interacting binaries. We find that the extent to which an observer sees the shape of the Roche-lobe of the secondary star governs the amount of distortion of the absorption line profiles. The width and degree of asymmetry of the phase-resolved absorption line profiles show a characteristic shape, which depends primarily on the binary inclination and gravity darkening exponent. We show that, in principle, by obtaining high spectral and time resolution spectra of quiescent cataclysmic variables or low mass X-ray binaries in which the mass-losing star is visible, fitting the shape of absorption line profiles will allow one to determine not only the mass function of the binary, but also the binary inclination and hence the mass of the binary components.
In this model, without dark matter, the flat rotation curves of galaxies and the mass-to-light ratios of clusters of galaxies are described quantitatively. The hypothesis is that the agent of gravitational...Full Text Available
BackgroundAdnexal masses are not uncommon in patients with breast cancer. Breast cancer and ovarian malignancies are known to be associated. In patients with breast cancer and co-existing...Full Text Available
This report summarises nearly 20 biosphere reports and gives a synthesis of the work performed within the SR-Site Biosphere project, i.e. the biosphere part of SR-Site. SR-Site Biosphere provides the main project with dose conversion factors (LDFs), given a unit release rate, for calculation of human doses under different release scenarios, and assesses if a potential release from the repository would have detrimental effects on the environment. The intention of this report is to give sufficient details for an overview of methods, results and major conclusions, with references to the biosphere reports where methods, data and results are presented and discussed in detail. The philosophy of the biosphere assessment was to make estimations of the radiological risk for humans and the environment as realistic as possible, based on the knowledge of present-day conditions at Forsmark and the past and expected future development of the site. This was achieved by using the best available ...
Full text of publication follows: Different to the very simple class of homogeneous non-equilibrium models (HEM) an one dimensional thermal-hydraulic theoretical drift-flux based and thus non-homogeneous coolant channel model and, as a result, an in itself complete thermal-hydraulic coolant channel module CCM have been established allowing to simulate in a very general way the steady state and transient behaviour of the most important parameters of a single- or two-phase fluid flowing within any type of heated or non-heated coolant channel (with an eventually varying cross flow area). To avoid mathematical discontinuities at the transition from single- to two-phase flow the coolant channel will, in its general form, be split into different regions, i.e. be looked as a basic channel (BC) which can consist of a number of different flow regimes and can, accordingly, be subdivided into a number of sub-channels (SC-s). All of them belong, obviously, to only two types of SC-s, a SC with an ...
Iron concentration control in feedwater is one of the most important subjects in water chemistry. Especially for the BWR plants without 100% flow volume of hollow fiber filter (HFF), rather high iron concentration in feedwater is one of the big issues as this causes relatively high radiation dose rate in drywell area. Cation exchange resins especially used in the plants with partial flow rate of HFF are expected to have the important role of capturing iron in feedwater. For this purpose, we have investigated the effective method for using iron absorption characteristics of cation exchange resin. The Cation-Over Layer method (COL) in condensate demineralizers (CD) effectively utilizes these characteristics. In order to demonstrate a performance of the cation overlay method, we had applied this method for three CD vessels at Fukushima Daiichi NPP Unit 3 for testing purpose. The result of this actual plant test indicated that the iron ...
Indirect evaporative air coolers that use air-to-air plate-type heat exchangers show good promise (compared with compression air-conditioning systems) of extending the energy savings from arid, low-humidity areas to more widespread climatic conditions. However, no systematic experiment had been done concerning the effect of the wettability of aluminum plates on the effectiveness of the indirect evaporative cooling system. In this study, a testing apparatus was built where only one secondary channel and two primary channels were used so that different surfaces could be easily tested to determine the system`s effectiveness and the heat transfer coefficient. The advantage of this experimental apparatus is that plates of the heat exchanger can be easily changed in the test section instead of fabricating a complete heat exchanger for each test. A dynamic contact analyzer was used to quantitatively measure the wetting properties ...
The new frustrated square-lattice system, Pb{sub 2}VO(PO{sub 4}){sub 2}, has been investigated using polarised neutron scattering. From these studies, made on powdered samples, we have determined the nature of the exchange interactions and the magnetic ordering for this novel quantum magnet. Quantum order from disorder occurs at low temperature, and the ground state observed below the Neel temperature T {sub N}{approx}3.7 K is a collinear antiferromagnet. At room temperature there are no magnetic correlations and it is possible to model the scattering with the V{sup 4+} magnetic form factor. However, at T{approx}20 K, a temperature well into the paramagnetic phase, magnetic correlations are observed, and these spin correlations have been modelled using a high-temperature series expansion. Ferromagnetic nearest-neighbour exchange J {sub 1}{approx}-2 K and antiferromagnetic next-nearest-neighbour exchange J {sub 2}{approx}6.5 ...
The performance of larger than bench scale ion exchange systems is evaluated by using solutions containing trace amounts of "1"3"7Cs, "8"5Kr, and "1"3"1I, and large amounts of either NaCl or Na_2HPO_4, H_3BO_3, and LiOH. The significant finding in this study is that the empirical rules of ionic selectivity of strong acid cation and strong base anion resins were followed by all ionic species, even though concentrations of some macrocomponents were nearly 10"6 times those of trace components. Other results of possible importance are the correlation between the instantaneous decontamination factor (DF) and the efficiency of column exchange capacity utilization, and the concept of time average decontamination factor (anti DF). The plot of anti DF vs. feed throughput will serve as a guide in determining when the feed should be discontinued in order to achieve a desired anti DF. Both of these correlations are derived from the breakthrough curves.
The efficiency of the synthesized zeolite NaY from rice husk ash (RHA) in the removal of Cr(III) from aqueous solution was studied. Zeolite NaY was synthesized from RHA via seeding technique and the identification of its structure was done by X-ray Diffraction (XRD) technique and the elemental analysis was carried out by X-ray Fluorescence (XRF). The physicochemical properties which were related to the use of the zeolite NaY as a sorbent was also investigated. The synthesized zeolite NaY has higher cation exchange capacity (CEC) than the commercial zeolite NaY due to the higher amount of sodium content in the synthesized as well as the lower ratio of silica to alumina. The synthesized zeolite NaY together with the commercial one as comparison was used in the sorption of the Cr(III) in aqueous solution by batch sorption experiments. The kinetic study showed that the Cr(III) uptake by both zeolites were based on the pseudo second order model. Synthesized zeolite NaY ...
RADIANT{trademark} is manufactured by United States Surgical Corporation, Vascular Therapies Division, (formerly Progressive Angioplasty Systems). The system comprises a liquid {beta}-radiation source, a shielded isolation/transfer device (ISAT), modified over-the-wire or rapid exchange delivery balloons, and accessory kits. The liquid {beta}-source is Rhenium-188 in the form of sodium perrhenate (NaReO{sub 4}), Rhenium-188 is primarily a {beta}-emitter with a physical half-life of 17.0 hours. The maximum energy of the {beta}-particles is 2.1 MeV. The source is produced daily in the nuclear pharmacy hot lab by eluting a Tungsten-188/Rhenium-188 generator manufactured by Oak Ridge National Laboratory (ORNL). Using anion exchange columns and Millipore filters the effluent is concentrated to approximately 100 mCi/ml, calibrated, and loaded into the (ISAT) which is subsequently transported to the cardiac catheterization laboratory. The delivery ...
Thin PTFE membranes were prepared by coating the PTFE dispersion onto the aluminum films. Thus the thin crosslinked PTFE (RX-PTFE) membranes were obtained by means of electron beam irradiation above the melting temperature of PTFE under oxygen-free atmosphere. The RX-PTFE membranes were pre-irradiated and grafted by styrene with or without divinylbenzene (DVB) in liquid phase. The existence of DVB accelerated the initial grafting rate. The styrene grafted RX-PTFE membranes are white colored, on the other hand, the styrene/DVB grafted RX-PTFE membranes are colorless. The proton exchange membranes (PEMs) were obtained by sulfonating the grafted membranes using chlorosulfonic acid. The ion exchange capacity (IEC) values of the PEMs ranging from 1.5 to 2.8 meq/g were obtained. The PEMs made from the styrene/DVB grafted membranes showed higher chemical stability than those of the styrene grafted membranes under oxidative circumstance.
The service conditions for high-temperature heat-exchangers with helium coolant of HTGRs and requirements imposed on materials for their production are discussed. The choice of nickel-base alloys with solid-solution hardening for long-term service at high temperatures is grounded. Results of study on properties and structure of types Ni-25Cr-5W-5Mo and Ni-20Cr-20W alloy in the temperature range of 900 deg. - 1,000 deg. C are given. The ageing of Ni-25Cr-5W-5Mo alloy at 900 deg. - 950 deg. C results in decreased corrosion-mechanical properties and is caused by the change of structural metal stability. Alloy with 20% tungsten retains a high stability of both structure and properties after prolonged exposure in helium at above temperatures. The alloy has also increased resistance to delayed fracture and low-cycle fatigue at high temperatures. The developed alloy of type Ni-20Cr-20W with microalloying is recommended for production of tubes for HTGR high-temperature ...
Amphiphilic block copolymers are synthesized by sulfonation of poly(styrene-b-methyl methacrylate) (PS-b-PMMA) using acetyl sulfate, and are blended with poly(vinylidene fluoride) (PVDF) to prepare a new proton exchange membrane, in which PMMA is miscible with PVDF. The morphology and the transport properties of the membranes are investigated as functions of the degree of sulfonation as well as the blend ratio. Notable transition of phase-separated morphology is observed as the PVDF content of the blend is increased. Both the proton conductivity and the ion-exchange capacity (IEC) of the membrane increase with increasing the degree of sulfonation of PS-b-PMMA, and they are also enhanced as the phase-separated domains of blend membrane are well-ordered. Unlike the Nafion membrane, the proton conductivity of the blend membrane increases up to 90 C, indicating the blend membrane shows better thermal stability than the Nafion membrane. (author)
Heat exchangers for high and ultrahigh temperatures are a need and a precondition to realise high efficient fossil fired power plants based on the so-called Externally Fired Combined Cycle (EFCC) or the Indirect Fired Gas Turbines (IFGT). The main target of both processes is to increase the thermal efficiency of existing power plants by approximately 25% resulting in the same decrease in fuel consumption and, therefore, in the same reduction of CO{sub 2} formation. The main activities of the MPA University of Stuttgart in this project is focused on the characterisation and qualification of the structural material of the ultrahigh temperature heat exchanger (UHTHE) necessary in the above mentioned processes. The influence of the temperature and load on the material behaviour have been analysed by means of tensile tests and creep tests. The effectiveness of different coating systems and the interaction between coating system and basic material ...
Five cycles of loading, elution, and regeneration were performed to remove technetium from a Hanford waste sample retrieved from Tank 241-AW-101 using SuperLig 639 resin. The waste sample was diluted to 4.95 M Na plus and then was processed to remove 137Cs through dual ion exchange columns each containing 15 mL of SuperLig 644. To remove 99Tc, the cesium decontaminated solution was processed downwards through two ion exchange columns, each containing 12 mL of SuperLig 639 resin. The columns, designated as lead and lag, each had an inside diameter of 1.45 cm and a height of 30 cm. The columns were loaded in series, but were eluted and then regenerated separately. The average technetium loading for the cycles was 250 BV at 10 percent breakthrough. There was no significant difference in the loading performances among the five cycles. The percent removal of 99Tc was greater than 99.94 percent and the average decontamination factor (DF) was ...
An ion exchange unit has been manufactured for WSRC by British Nuclear Fuels, Ltd. This unit consists of three columns, ancillary valving, pumps, lines, and computer controls. It has been delivered to TNX for use in testing a cesium-specific ion exchange resin, developed at WSRC as a potential second generation process for the decontamination of Defense Waste Processing Facility (DWPF) supernate. This resin also has Department of Energy applications at both Oak Ridge and Hanford. Oak Ridge is interested in decontaminating the Melton Valley storage tank supernate, while Hanford is interested in decontaminating the 101-AW and 101-SY supernate streams. Another potential developmental interest is the Savannah River Site (SRS) DWPF recycle stream. The three primary waste streams of interest are the Oak Ridge, Hanford, and SRS, SWPF supernate streams. For these three waste streams, the cesium decontamination factor (DF) will be measured for a ...
Abstract The synthesis, crystal structure and magnetic characterisation by magnetisation and inelastic neutron scattering (INS) of a mixed-valent Mn10 supertetrahedral aggregate [MnIII6MnII4(4-O)4(3-N3)3(3-Br)(Hmpt)6(Br)]Br0.7(N3)0.3-2-MeOH-3-MeCN (1) (H3mpt=3-methylpentan-1,3,5-triol) is reported. The magnetic core of the molecule can be described as an octahedron of six S=2 MnIII ions with four faces, each capped by a S=5/2 MnII ion such as to form the supertetrahedron. Unlike most related complexes, the molecular symmetry is slightly reduced from approximately Td to C3. The magnetic data reveal a total spin of S=22 in the ground state due to ferromagnetic exchange couplings within the molecule. The combined INS and magnetic data permits the accurate determination of the exchange couplin...
Recent nuclear power plants require high purity water to protect nuclear reactors or steam generators from SCC and maintain in good condition. In this connection, it is especially important to minimize sulfate, which is a corrosive chemical originated from oxidative degradation of cation exchange resins during operation. Recently, uniform particle size (UPS) strong acid cation gel resin with 14% cross-linkage, which has excellent stability against oxidization, has been applied to several condensate purification systems. For further improvement of water quality, some methods for changing the configuration of condensate demineralizer's resin bed have been examined. For example, these methods correspond to anion under layer and cation over layer. We have tested these methods by cold column tests. Furthermore, we have developed the newly anion exchange resin having higher efficiency and capacity for absorbing leachables from cation ...
Heat transfer enhancement in a heat exchanger tube by installing a baffle is reported. The effect of baffle size and orientation on the heat transfer enhancement was studied in detail. Three different baffle arrangements were considered. The results show that for the vertical baffle, an increase in the baffle height causes a substantial increase in the Nusselt number but the pressure loss is also very significant. For the inclined baffles, the results show that the Nusselt number enhancement is almost independent of the baffle inclination angle, with the maximum and average Nusselt number 120% and 70% higher than that for the case of no baffle, respectively. For a given baffle geometry, the Nusselt number enhancement is increased by more than a factor of two as the Reynolds number decreased from 20,000 to 5000. Simulations were conducted by introducing another baffle to enhance heat transfer. The results show that the average Nusselt number for the two baffles case ...
The Geothermal Heat Pump (GHP) concept was originally developed in the 1940`s. Recently, because of increasing energy costs, utility interest, and the development of simple and durable ground source heat exchangers, GHP`s have gained international attention as a proven means of energy conservation and electrical peak power demand reduction. GHP systems require installation of a buried heat exchanger to utilize the nearly constant ground temperature making them more efficient than conventional air source heat pumps. However, the high installation cost for both residential and commercial applications is a major obstacle to their market penetration. Sandia National Laboratories (SNL) through its sponsors, the Department of Energy (DOE), and the Department of Defense (DOD), has embarked on a research program to find ways to reduce GHP installation costs and improve performance, thereby increasing their market penetration. The major elements of the ...
A gas-fired boiler plant comprises a burner bed extending over a flat surface and heat exchanger pipes arranged above the burner bed, parallel to the said surface. The heat exchanger tubes comprise pipes equipped with a pluraltiy of flat ribs which extend substantially radially from the said pipes and which are provided in space arrangement over the length of the said heat exchanger pipes. The ribs are provided with bent-off portions. The hot flue gases rising from the burner bed flow through the gaps formed between the said ribs and pipes. In order to improve both the convective heat transmission and the utilization of the radiant heat, the bent-over edges are inclined, at least partly, relative to the surface of said burner bed, the arrangement being selected in a manner to ensure that bent-over portions point towards the burner bed and the rising flue gased are guided around the pipes along a roughly semi-circular path.
This paper describes the field performance of air conditioning with an energy pile system, which was applied to the pile foundations of an actual building for the purpose of reducing the cost of the underground heat exchanger. First, the building for both office and residential use, for which a space heating and cooling system using friction piles was installed, was built in Sapporo in December 2000. Second, three tests were carried out to specify the design of a heat exchanger inside the pile, and a U-tube type underground heat exchanger was adopted from the viewpoint of energy efficiency and installation costs. Long-term space heating operation measurements indicated that the seasonal average temperatures of brine returning from the underground and pile surfaces were 2.4 and 6.7 deg C, respectively. The average coefficient of performance for space heating was quite high at 3.9, and the seasonal primary energy reduction ...
A detailed study of adsorption of automobile exhaust hydrocarbons in Ag{sup +}-exchanged zeolites under cold-start conditions (room temperature and in the presence of water) was carried out with FT-IR spectroscopy, using toluene and propylene as probes. The results show that exchanged Ag{sup +} in zeolites is unique for trapping olefin and aromatic hydrocarbons due to its resistance to water adsorption. In contrast, exchanged Cu{sup 2+} in zeolites, which has good hydrocarbon trapping properties under dry conditions, does not trap hydrocarbons under wet conditions. Here, solvation of Cu{sup 2+} screens the interactions of the cation with adsorbed hydrocarbons. The results also show that, in addition to the nature of the cation, the structure of the zeolite also plays a role in hydrocarbon trapping. Aging at high temperatures, with water vapor (=10%) and SO{sub 2} (=15ppm), leads to a decrease of the trapping centers in the ...
Rotationally resolved spectra of kinetic energy releases epsilon-c in predissociations of H/sub 2/, after dissociative charge exchange of H/sub 2/ /sup +/ with Cs atoms, are obtained. The experiments are performed with natural and with pure parahydrogen. The predissociations with epsilon-c<1.9 eV constitute less than 5% of the total amount of dissociations to HXchemically bondH at a beam energy of 5 keV. All strong rotational peaks observed could be attributed to n = 3 Rydberg states which predissociate to H(1s)+H(2l). Vibrational-rotational series are observed of the d /sup 3/Pi/sub u//sup +/, D /sup 1/Pi/sub u//sup +/, and J /sup 1/..delta../sub g//sup +/ states. Predissociation by barrier tunneling is reported of v = 4 levels of the h /sup 3/..sigma../sub g//sup +/ state and of v = 4 and 5 levels of the i /sup 3/Pi/sub g/ state. Selectivity of the charge-exchange process for different n = 3 states, or even for different parity states, is ...
A mathematical model is described for determining the level profile along the length of heat exchange tubes in a horizontal steam generator, and for determining the conditions in the steam cushion under the perforated sheet. The water level area is divided in the model into 36 partial elements; for analysis of the conditions under the level, the steam-water space is divided into four areas. The results of the calculations were compared with measurement results for the steam generator rated values. Very good agreement was found. The results show that, among others, the supply water distribution very much affects the conditions in the area of the steam cushion and of the bubble vacuum. Also, the average steam load of the inner bundle tubes is significantly higher than that of the outer bundles. It was also shown that permanent steam generator operation with exposed top tube rows may occur even in some permissible operating conditions. This is mainly due to the fact ...
To carry out studies on the radon behavior under controlled and stable conditions it was designed and constructed a system that consists of two parts: a container of mineral rich in Uranium and an experimentation chamber with radon united one to the other one by a step valve. The container of uranium mineral approximately contains 800 gr of uranium with a law of 0.28%; the radon gas emanated by the mineral is contained tightly by the container. When the valve opens up the radon gas it spreads to the radon experimental chamber; this contains 3 accesses that allow to install different types of detectors. The versatility of the system is exemplified with two experiments: 1. With the radon experimental chamber and an associated spectroscopic system, the radon and two of its decay products are identified. 2. The design of the system allows to couple the mineral container to other experimental geometries to demonstrate this fact it was coupled and proved a new automatic ...
Metabolic carbon labelling experiments enable a large amount of extracellular fluxes and intracellular carbon isotope enrichments to be measured. Since the relation between the measured quantities and the unknown intracellular metabolic fluxes is given by bilinear balance equations, flux determination from this data set requires the numerical solution of a nonlinear inverse problem. To this end, a general algorithm for flux estimation from metabolic carbon labelling experiments based on the least squares approach is developed in this contribution and complemented by appropriate tools for statistical analysis. The linearization technique usually applied for the computation of nonlinear confidence regions is shown to be inappropriate in the case of large exchange fluxes. For this reason a sophisticated compactification transformation technique for nonlinear statistical analysis is developed. Statistical analysis is then performed by computing appropriate statistical ...
One option in establishing advanced technology for disposing of high-level radioactive waste (HLW) is to remove TRU elements from HLW and then transform them into short-lived radionuclides. Tertiary pyridine-type anion exchange resin was investigated as a separation medium for spent fuel reprocessing using a HCl solution. Distribution coefficients of typical elements, along with uranium, were measured in the pyridine resin--HCl solution system, where HCl concentration was varied from 1 to 9 M. The results reveal: elements of the alkali metal, alkaline earth and lanthanide groups are not adsorbed, the adsorption patterns of the transition metals differ according to HCl concentration, and uranium is adsorbed in the high HCl concentration region. Furthermore, the present report describes the experimental results obtained for the adsorption behaviour of uranium, americium, curium and various lanthanide elements on tertiary pyridine-type anion ...
We present an abundance analysis based on high-resolution spectra of 10 stars selected to span the full range in metallicity in the Ursa Minor (UMi) dwarf spheroidal (dSph) galaxy. We find that [Fe/H] for the sample stars ranges from -1.35 to -3.10 dex. Combining our sample with previously published work for a total of 16 luminous UMi giants, we establish the trends of abundance ratios [X/Fe] as functions of [Fe/H] for 15 elements. In key cases, particularly for the #alpha#-elements, these trends resemble those for stars in the outer part of the Galactic halo, especially at the lowest metallicities probed. The neutron-capture elements show an r-process distribution over the full range of Fe metallicity reached in this dSph galaxy. This suggests that the duration of star formation in the UMi dSph was shorter than in other dSph galaxies. The derived ages for a larger sample of UMi stars with more uncertain metallicities also suggest a population dominated by uniformly old (#approx#13 ...
The development of attenuated response ({open_quotes}tolerance{close_quotes}) to daily ozone (O{sub 3}) exposures in the laboratory is well established in healthy adult volunteers. However, the capability of asthmatics to develop tolerance during multiday ozone exposures in unclear. We exposed 10 adult volunteers with mild asthma to 0.4 ppm O{sub 3} in filtered air for 3 h/d on 5 consecutive d. Two similar filtered-air exposures during the preceding week served as controls. Follow-up O{sub 3} exposures were performed 4 and 7 d after the most recent consecutive exposure. All exposures were performed in an environmental chamber at 31 {degrees}C and 35% relative humidity. The subjects performed moderate exercise (mean ventilation rate of 32 l/min) for 15 min of each half-hour. Responses were measured with spirometry and symptom evaluations before and after each exposure, and a bronchial reactivity test (methacholine challenge) was conducted after each exposure. All ...
A method, based on anion exchange chromatography, is presented for the isolation of "1"3"9Ce after production by a proton-induced nuclear reaction on a thick praseodymium target. After bombardment the target is dissolved in nitric acid and "1"3"9Ce oxidised to the Ce(IV) oxidation state with bromic acid. "1"3"9Ce is then separated form the praseodymium by anion exchange chromatography on a Ag MP-1 resin column in a nitric acid - bromic acid mixture. "1"3"9Ce is sorbed onto the resin column and praseodymium eluted with the acid mixture. The bromic acid is washed out of the column with nitric acid and "1"3"9Ce finally eluted with dilute nitric acid containing sulphur dioxide.
Bisaminoethanethiol (BAT) ligands with various gem-dimethyl and amide groups were prepared, and the corresponding neutral Tc-99m complexes were prepared and evaluated for their relative stabilities by ligand-exchange reactions. It was demonstrated that technetium complexes containing gem-dimethyl substituents have higher lipophilicities, whereas those with an amide group possess greater stability, which enhances ligand-exchange reaction. The most interesting observation was that the brain uptake in rats is not determined only by lipophilicity. Apparently, Tc-99m complexes with an amide functional group display lower brain uptakes in rats compared to those without an amide group. The brain uptake was strongly influenced by substituents on the BAT ligand. These factors are critically important and should be taken into consideration when designing Tc-99m-labeled agents for CNS receptor imaging.
Gas nitridation has shown excellent promise to form dense, electrically conductive and corrosion-resistant Cr-nitride surface layers on Ni-Cr base alloys for use as proton exchange membrane fuel cell (PEMFC) bipolar plates. Due to the high cost of nickel, Fe-base bipolar plate alloys are needed to meet the cost targets for many PEMFC applications. Unfortunately, nitridation of Fe-base stainless steel alloys typically leads to internal Cr-nitride precipitation rather than the desired protective surface nitride layer formation, due to the high permeability of nitrogen in these alloys. This paper reports the finding that it is possible to form a continuous, protective Cr-nitride (CrN and Cr2N) surface layer through nitridation of Fe-base stainless steel alloys. The key to form a protective Cr...
The interlayer exchange coupling between Co/Pt perpendicular-to-plane magnetized layers across a thin IrMn spacer layer was experimentally studied. In contrast to earlier studies on interlayer coupling through antiferromagnetic NiO, which revealed an oscillatory coupling behavior as a function of NiO thickness, a ferromagnetic coupling was observed here in the range of IrMn thickness between 0.6 and 1.5nm and antiferromagnetic between 1.5 and 2.5nm. The antiferromagnetic coupling is attributed to an orange peel magnetostatic mechanism whereas the ferromagnetic coupling is attributed to an out-of-plane polarization of the antiferromagnetic IrMn layer induced by the interfacial exchange interaction with the adjacent out-of-plane ferromagnetic layers. Measurements of hysteresis loops versus t...
An energy saving self-powered industrial dehumidifier for use in a building having a tap water conduit leading from a source of supply to utilization points is described comprising: a dehumidifying apparatus positioned in a stream of air to be dehumidified in the building. The dehumidifying apparatus comprising conduit means for diverting at least a portion of a relatively continuously moving stream of tap water from the tap water conduit through a heat exchanger positioned in a stream of air and returning the diverted portion to the tap water stream upstream of the utilization points. Water vapor in the stream of air will condense onto the heat exchanger when the tap water has a temperature below a dew point temperature of the air stream, thereby dehumidifying the air stream.
ABSTRACT Drought is an important seedling mortality agent in dry and moist tropical forests, and more severe and frequent droughts are predicted in the future. The effect of drought on leaf gas exchange and seedling survival was tested in a dry-down experiment with four tree species from dry and moist forests in Bolivia. Seedlings were droughted and wilting stage and gas exchange were monitored. Drought led to a gradual reduction of photosynthesis and stomatal conductance over time, whereas respiration and photosynthetic water-use efficiency initially increased with drought and then declined. Seedlings gradually went through the different wilting stages, until they eventually died, but the trajectory differed for the four species. The strong relationship between wilting stage and photosynt...
Shaped activated charcoal is modified by 02 and N2 processing for producing coal compounds with higher acidic or basic properties. Nitrated activated charcoal has properties of a weak anionite with a substantially increased ion exchange capacity with an increase in the concentration of the hydrogen ions in the electrolyte and adsorbs iodine ions well from aqueous solutions at a pH of less than 5. A layer of nitrated charcoal is a very effective sorbent in the process of dynamic sorption of iodine anions from acetic solutions of KI. It is also established that the sorption of iodine ions in the activated charcoal modified by 02 occurs in accordance with an ion exchange mechanism (and possibly, selective sorption). This refutes literature data which ascribe the determining participation in the process to the reaction of oxidation of iodides on the surface (Pv) of the coal into free I2.