Continuous deionization of a dilute nickel solution

NARCIS (Netherlands)

Spoor, P.B.; Koene, L.; Veen, ter W.R.; Janssen, L.J.J.

2002-01-01

This paper describes the continuous removal of nickel ions from a dilute solution using a hybrid ion-exchange/electrodialysis process. Emphasis was placed on the ionic state of the bed during the process, and the mass balance of ions in the system. Much of this information was obtained by analysing

A NOVEL INTERPRETATION OF CONCENTRATION DEPENDENCE OF VISCOSITY OF DILUTE POLYMER SOLUTION

Institute of Scientific and Technical Information of China (English)

Yan Pan; Rong-shi Cheng

2000-01-01

The concentration dependence of the reduced viscosity of dilute polymer solution is interpreted in the light of a new concept of the self-association of polymer chains in dilute solution. The apparent self-association constant is defined as the molar association constant divided by the molar mass of individual polymer chain and is numerically interconvertible with the Huggins coefficient. The molar association constant is directly proportional to the effective hydrodynamic volume of the polymer chain in solution and is irrespective of the chain architecture. The effective hydrodynamic volume accounts for the non-spherical conformation of a short polymer chain in solution and is a product of a shape factor and hydrodynamic volume. The observed enhancement of Huggins coefficient for short chain and branched polymer is satisfactorily interpreted by the concept of self-association. The concept of self-association allows us to predict the existence of a boundary concentration Cs (dynamic contact concentration) which divides the dilute polymer solution into two regions.

High-throughput ab-initio dilute solute diffusion database.

Science.gov (United States)

Wu, Henry; Mayeshiba, Tam; Morgan, Dane

2016-07-19

We demonstrate automated generation of diffusion databases from high-throughput density functional theory (DFT) calculations. A total of more than 230 dilute solute diffusion systems in Mg, Al, Cu, Ni, Pd, and Pt host lattices have been determined using multi-frequency diffusion models. We apply a correction method for solute diffusion in alloys using experimental and simulated values of host self-diffusivity. We find good agreement with experimental solute diffusion data, obtaining a weighted activation barrier RMS error of 0.176 eV when excluding magnetic solutes in non-magnetic alloys. The compiled database is the largest collection of consistently calculated ab-initio solute diffusion data in the world.

Effect of alkali-earth ions on local structure of the LaAlO3-La0.67A0.33MnO3 (A = Ca, Sr, Ba) diluted solid solutions: 27Al NMR studies

International Nuclear Information System (INIS)

Charnaya, E.V.; Cheng Tien; Lee, M.K.; Sun, S.Y.; Chejina, N.V.

2007-01-01

27 Al Magic Angle Spinning (MAS) NMR studies are carried out for diluted alkali-earth metal doped lanthanum manganite solid solutions in the lanthanum aluminate (1-y)LaAlO 3 -yLa 0.67 A 0.33 MnO 3 (A = Ca, Sr, Ba) with y = 0, 2, 3, and 5 mol %. The spectra depend on the dopant species and show higher substitutional ordering for the Ba containing mixed crystals. Magnetically shifted lines are observed in all solid solutions and attributed to Al in the octahedral oxygen environment near manganese trivalent ions. Nonlinear dependences of their intensity are referred to the manganese-rich cluster formation. An additional MAS NMR line corresponding to aluminium at sites different from the octahedral site in pure LaAlO 3 is observed only in solutions doped with Ba. 3Q MAS NMR revealed that the broadening of this line is governed mainly by quadrupole coupling and allowed calculating the isotropic chemical shift [ru

Calorimetric study of interaction of barium hydroxide with diluted solutions of hydrofluoric acid

International Nuclear Information System (INIS)

Kurbanov, A.R.; Sharipov, D.Sh.

1993-01-01

Present article is devoted to calorimetric study of interaction of barium hydroxide with diluted solutions of hydrofluoric acid. The calorimetric study of interaction of barium hydroxide with diluted solutions of hydrofluoric acid was carried out in order to determine the thermal effects of reactions. The results of interaction of Ba(OH) 4 ·8H 2 O with 5, 10, and 20% solution of hydrofluoric acid were considered.

X-ray absorption spectroscopy of diluted system by undulator photon source and multi-element solid-state detector

CERN Document Server

Tanida, H

2001-01-01

In order to measure the extended X-ray absorption fine structure (EXAFS) spectrum of an ultra-diluted system, an optics and detector control system for a synchrotron radiation beamline is developed. The undulator gap width is continuously tuned to obtain the maximum X-ray photon flux during the energy scan for the EXAFS measurement. A piezoelectric translator optimizes the parallelism of the double crystal in a monochromator at each measurement point to compensate for mechanical errors of the monochromator, resulting in a smooth and intense X-ray photon flux during the measurement. For a detection of a weak fluorescence signal from diluted samples, a 19-element solid-state detector and digital signal processor are used. A K-edge EXAFS spectrum of iron in a myoglobin aqueous solution with a concentration of 5.58 parts per million was obtained by this system.

Dielectric relaxation studies of dilute solutions of amides

Energy Technology Data Exchange (ETDEWEB)

Malathi, M.; Sabesan, R.; Krishnan, S

2003-11-15

The dielectric constants and dielectric losses of formamide, acetamide, N-methyl acetamide, acetanilide and N,N-dimethyl acetamide in dilute solutions of 1,4-dioxan/benzene have been measured at 308 K using 9.37 GHz, dielectric relaxation set up. The relaxation time for the over all rotation {tau}{sub (1)} and that for the group rotation {tau}{sub (2)} of (the molecules were determined using Higasi's method. The activation energies for the processes of dielectric relaxation and viscous flow were determined by using Eyring's rate theory. From relaxation time behaviour of amides in non-polar solvent, solute-solvent and solute-solute type of molecular association is proposed.

A theoretical framework for modeling dilution enhancement of non-reactive solutes in heterogeneous porous media.

Science.gov (United States)

de Barros, F P J; Fiori, A; Boso, F; Bellin, A

2015-01-01

Spatial heterogeneity of the hydraulic properties of geological porous formations leads to erratically shaped solute clouds, thus increasing the edge area of the solute body and augmenting the dilution rate. In this study, we provide a theoretical framework to quantify dilution of a non-reactive solute within a steady state flow as affected by the spatial variability of the hydraulic conductivity. Embracing the Lagrangian concentration framework, we obtain explicit semi-analytical expressions for the dilution index as a function of the structural parameters of the random hydraulic conductivity field, under the assumptions of uniform-in-the-average flow, small injection source and weak-to-mild heterogeneity. Results show how the dilution enhancement of the solute cloud is strongly dependent on both the statistical anisotropy ratio and the heterogeneity level of the porous medium. The explicit semi-analytical solution also captures the temporal evolution of the dilution rate; for the early- and late-time limits, the proposed solution recovers previous results from the literature, while at intermediate times it reflects the increasing interplay between large-scale advection and local-scale dispersion. The performance of the theoretical framework is verified with high resolution numerical results and successfully tested against the Cape Cod field data. Copyright © 2015 Elsevier B.V. All rights reserved.

Procedures for accurately diluting and dispensing radioactive solutions

International Nuclear Information System (INIS)

1975-01-01

The technique currently used by various laboratories participating in international comparisons of radioactivity measurements are surveyed and recommendations for good laboratory practice established. Thus one describes, for instance, the preparation of solutions, dilution techniques, the use of 'pycnometers', weighing procedures (including buyoancy correction), etc. It should be possible to keep random and systematic uncertainties below 0.1% of the final result

Opalescence in monoclonal antibody solutions and its correlation with intermolecular interactions in dilute and concentrated solutions.

Science.gov (United States)

Raut, Ashlesha S; Kalonia, Devendra S

2015-04-01

Opalescence indicates physical instability of a formulation because of the presence of aggregates or liquid-liquid phase separation in solution and has been reported for monoclonal antibody (mAb) formulations. Increased solution opalescence can be attributed to attractive protein-protein interactions (PPIs). Techniques including light scattering, AUC, or membrane osmometry are routinely employed to measure PPIs in dilute solutions, whereas opalescence is seen at relatively higher concentrations, where both long- and short-range forces contribute to overall PPIs. The mAb molecule studied here shows a unique property of high opalescence because of liquid-liquid phase separation. In this study, opalescence measurements are correlated to PPIs measured in diluted and concentrated solutions using light scattering (kD ) and high-frequency rheology (G'), respectively. Charges on the molecules were calculated using zeta potential measurements. Results indicate that high opalescence and phase separation are a result of the attractive interactions in solution; however, the presence of attractive interactions do not always imply phase separation. Temperature dependence of opalescence suggests that thermodynamic contribution to opalescence is significant and Tcloud can be utilized as a potential tool to assess attractive interactions in solution. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

High temperature thermodynamics of H2 and D2 in titanium, and in dilute titanium oxygen solid solutions

International Nuclear Information System (INIS)

Dantzer, P.

1983-01-01

The Tian Calvet microcalorimetric method has been improved in order to determine ΔH-barsub(H)(D), the partial molar enthalpy of mixing of hydrogen (deuterium) in the Ti-H 2 (D 2 ) solid systems for compositions 0 2 solid solutions (y = (O/Ti)) at 745 K. The combined calorimetric and equilibrium method allows a precise evaluation of the partial molar entropies. The results of this study differ substantially from earlier published data. (author)

Electrochemical reduction of dilute chromate solutions on carbon felt electrodes

NARCIS (Netherlands)

Frenzel, Ines; Frenzel, I.; Holdik, Hans; Barmashenko, Vladimir; Stamatialis, Dimitrios; Wessling, Matthias

2006-01-01

Carbon felt is a potential material for electrochemical reduction of chromates. Very dilute solutions may be efficiently treated due to its large specific surface area and high porosity. In this work, the up-scaling of this technology is investigated using a new type of separated cell and

Electrochemical reduction of metal ions in dilute solution using hydrogen

NARCIS (Netherlands)

Portegies Zwart, I.; Wijnbelt, E.C.W.; Janssen, L.J.J.

1995-01-01

Reduction of metal ions in dilute solutions is of great interest for purification of waste waters and process liquids. A new electrochemical cell has been introduced. This cell - a GBC-cell - is a combination of a gasdiffusion electrode in direct contact with a packed bed of carbon particles.

Optical absorption of dilute solutions of metals in molten salts

Energy Technology Data Exchange (ETDEWEB)

Senatore, G.; Parrinello, M.; Tosi, M.P. (Trieste Univ. (Italy). Ist. di Fisica Teorica; Gruppo Nazionale di Struttura dell material del CNR, Trieste (Italy); International Centre for Theoretical Physics, Trieste (Italy))

1978-12-23

The theory of liquid structure for fluids of charged hard spheres is applied to an evaluation of the F-centre model for valence electrons in metal-molten salt solutions at high dilution. Minimization of the free energy yields the groundstate radius of the elctron bubble and hence the optical excitation energy in a Franck-Condon transition, the shift and broadening of the transition due to fluctuations in the bubble radius, the volume of mixing, and the activity of the salt in the solution.

Performance and techno-economic assessment of several solid-liquid separation technologies for processing dilute-acid pretreated corn stover.

Science.gov (United States)

Sievers, David A; Tao, Ling; Schell, Daniel J

2014-09-01

Solid-liquid separation of pretreated lignocellulosic biomass slurries is a critical unit operation employed in several different processes for production of fuels and chemicals. An effective separation process achieves good recovery of solute (sugars) and efficient dewatering of the biomass slurry. Dilute acid pretreated corn stover slurries were subjected to pressure and vacuum filtration and basket centrifugation to evaluate the technical and economic merits of these technologies. Experimental performance results were used to perform detailed process simulations and economic analysis using a 2000 tonne/day biorefinery model to determine differences between the various filtration methods and their process settings. The filtration processes were able to successfully separate pretreated slurries into liquor and solid fractions with estimated sugar recoveries of at least 95% using a cake washing process. A continuous vacuum belt filter produced the most favorable process economics. Copyright © 2014 Elsevier Ltd. All rights reserved.

Isotope dilution alpha spectrometry for the determination of plutonium concentration in irradiated fuel dissolver solution : IDAS and R-IDAS

International Nuclear Information System (INIS)

Ramaniah, M.V.; Jain, H.C.; Aggarwal, S.K.; Chitambar, S.A.; Kavimandan, V.D.; Almaula, A.I.; Shah, P.M.; Parab, A.R.; Sant, V.L.

1980-01-01

The report presents a new technique, Isotope Dilution Alpha Spectrometry (IDAS) and Reverse Isotope Dilution Alpha Spectrometry (R-IDAS) for determining the concentration of plutonium in the irradiated fuel dissolver solution. The method exploits sup(238)Pu in IDAS and sup(239)Pu in R-IDAS as a spike and provides an alternative method to Isotope Dilution Mass Spectrometry (IDMS) which requires enriched sup(242)Pu as a spike. Depending upon the burn-up of the fuel, sup(238)Pu or sup(239)Pu is used as a spike to change the sup(238)Pu/(sup(239)Pu+sup(240)Pu)α activity ratio in the sample by a factor of 10. This change is determined by α-spectrometry on electrodeposited sources using a solid state silicon surface barrier detector coupled to a multichannel analyser. The validity of a simple method based on the geometric progression (G.P.) decrease for the far tail of the spectrum to correct for the tail contribution of sup(238)Pu peak (5.50 MeV) to the low energy sup(239)Pu + sup(240)Pu peak (5.17 MeV) is established. Results for the plutonium concentration on different irradiated fuel dissolver solutions with burn-uo ranging from J,000 to 100,000 MWD/TU are presented and compared with those obtained by IDMS. The values obtained by IDAS or R-IDAS and IDMS agree within 0.5%. (auth.)

A Dilute-Limit Heat of Solution of 3d Transition Metals in Iron Studied with 57Fe Moessbauer Spectroscopy

International Nuclear Information System (INIS)

Chojcan, Jan

2004-01-01

The room-temperature 57 Fe Moessbauer spectra for binary iron-based solid solutions Fe 1-x D x with D=V, Cr, Mn and Co, were analysed in terms of binding energy E b between two D atoms in the Fe-D system. The extrapolated values of E b for x=0 were used for computation of the dilute-limit heat of solution of D metals in iron. The results were compared with those derived from calorimetric data concerning the heat of formation of the systems mentioned as well as with those resulting from the Miedema's model of alloys. The comparison shows that our Moessbauer spectroscopy findings are in a qualitative agreement with the available calorimetric data and they are at variance with corresponding Miedema's values for Fe-Mn and Fe-Co systems.

Ion separation from dilute electrolyte solutions by nanofiltration

International Nuclear Information System (INIS)

Garcia, Corazon M.

2000-03-01

Nanofiltration (NF) is a pressure-driven process which is considered potential for the separation of ionic species selectively from solutions containing mixture of electrolyte solutes. The lower operating pressure requirement of NF than reverse osmosis (RO) makes the earlier potentially economical. In the separation of ions, many authors believed that there are membranes with characteristic fixed surface charge and that the mechanism of separation of ions is by the differences in valences of the ions. In this study, experiments involving dilute single-solute and multiple-solute electrolyte solutions were performed using three different NF membranes. Permeate fluxes and ion rejections of the different species of ions in samples of permeate solutions were measured at varied conditions. The mechanism of separation in NF was determined based on the analysis of the trends and behavior of ion rejection relative to the solution temperature, pressure, type of solute, feed concentration and feed solution pH. The results of the experiments show that there is no evidence of the presence of fixed surface charge on the NF membranes. Ion separation was made possible by the combination of sieve effect and ion-hydration effect. Ions having higher hydration numbers showed higher ion rejection than those having lower hydration numbers. A method to determine the effective membrane pore size of NF membranes using hydrodynamic model was proposed. The proposed method is based on the assumptions that the membrane is neutral and that the separation is based on sieving effect. (Author)

Effect of temperature on the dilution enthalpies of α,ω-amino acids in aqueous solutions

International Nuclear Information System (INIS)

Romero, C.M.; Cadena, J.C.; Lamprecht, I.

2011-01-01

Highlights: → The dilution of 3-amino propanoic acid, 4-amino butanoic acid, 5-amino pentanoic acid, and 6-amino hexanoic acid in water is an exothermic process at T = (293.15, 298.15, 303.15, and 308.15) K. → The limiting experimental slopes of the enthalpies of dilution with respect to the molality change Δm, are negative suggesting that the solutes interact with water primarily through their alkyl groups. → The value of the pairwise coefficient is positive at the temperatures considered, and the magnitude increases linearly with the number of methylene groups. → The comparison between the pairwise interaction coefficients for α,ω-amino acids and α-amino acids shows that the change in the enthalpic interaction coefficient is related to the relative position of the polar groups. - Abstract: Dilution enthalpies of aqueous solutions of 3-amino propanoic acid, 4-amino butanoic acid, 5-amino pentanoic acid, and 6-amino hexanoic acid were determined at T = (293.15, 298.15, 303.15, and 308.15) K using an LKB flow microcalorimeter. The homotactic interaction coefficients were obtained according to the McMillan-Mayer theory from the experimental data. For all the systems studied, the dilution of α,ω-amino acids in water is an exothermic process; the pair coefficients have positive values which increases with chain length. The obtained values of the interaction coefficients are interpreted in terms of solute-solvent and solute-solute interactions and are used as indicative of hydrophobic behavior of the amino acid studied.

Radionuclide solubility control by solid solutions

Energy Technology Data Exchange (ETDEWEB)

Brandt, F.; Klinkenberg, M.; Rozov, K.; Bosbach, D. [Forschungszentrum Juelich GmbH (Germany). Inst. of Energy and Climate Research - Nuclear Waste Management and Reactor Safety (IEK-6); Vinograd, V. [Frankfurt Univ. (Germany). Inst. of Geosciences

2015-07-01

The migration of radionuclides in the geosphere is to a large extend controlled by sorption processes onto minerals and colloids. On a molecular level, sorption phenomena involve surface complexation, ion exchange as well as solid solution formation. The formation of solid solutions leads to the structural incorporation of radionuclides in a host structure. Such solid solutions are ubiquitous in natural systems - most minerals in nature are atomistic mixtures of elements rather than pure compounds because their formation leads to a thermodynamically more stable situation compared to the formation of pure compounds. However, due to a lack of reliable data for the expected scenario at close-to equilibrium conditions, solid solution systems have so far not been considered in long-term safety assessments for nuclear waste repositories. In recent years, various solid-solution aqueous solution systems have been studied. Here we present state-of-the art results regarding the formation of (Ra,Ba)SO{sub 4} solid solutions. In some scenarios describing a waste repository system for spent nuclear fuel in crystalline rocks {sup 226}Ra dominates the radiological impact to the environment associated with the potential release of radionuclides from the repository in the future. The solubility of Ra in equilibrium with (Ra,Ba)SO{sub 4} is much lower than the one calculated with RaSO{sub 4} as solubility limiting phase. Especially, the available literature data for the interaction parameter W{sub BaRa}, which describes the non-ideality of the solid solution, vary by about one order of magnitude (Zhu, 2004; Curti et al., 2010). The final {sup 226}Ra concentration in this system is extremely sensitive to the amount of barite, the difference in the solubility products of the end-member phases, and the degree of non-ideality of the solid solution phase. Here, we have enhanced the fundamental understanding regarding (1) the thermodynamics of (Ra,Ba)SO{sub 4} solid solutions and (2) the

Radiation induced homogeneous precipitation in undersaturated solid-solutions

International Nuclear Information System (INIS)

Cauvin, Richard; Martin, Georges.

1978-01-01

The stability of various types of solid solutions under irradiation is studied. In this paper, observations made on AlZn solid solutions under 1 MeV electron irradiation are reported. Al-Zn was chosen as a prototype of solid solutions with a simple miscibility gap. It is shown that under appropriate irradiation conditions undersaturated AnZn solid solutions give rise to a homogeneous precipitation of coherent G.P. zones and of incoherent Zn precipitates the atomic volume of which is smaller than that of the matrix. We propose a more general treatment of solute concentration heterogeneities in solid solutions under irradiation and suggest how it might account for the nucleation of the observed phases. The growth of the observed precipitates is studied

End-Member Formulation of Solid Solutions and Reactive Transport

Energy Technology Data Exchange (ETDEWEB)

Lichtner, Peter C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2015-09-01

A model for incorporating solid solutions into reactive transport equations is presented based on an end-member representation. Reactive transport equations are solved directly for the composition and bulk concentration of the solid solution. Reactions of a solid solution with an aqueous solution are formulated in terms of an overall stoichiometric reaction corresponding to a time-varying composition and exchange reactions, equivalent to reaction end-members. Reaction rates are treated kinetically using a transition state rate law for the overall reaction and a pseudo-kinetic rate law for exchange reactions. The composition of the solid solution at the onset of precipitation is assumed to correspond to the least soluble composition, equivalent to the composition at equilibrium. The stoichiometric saturation determines if the solid solution is super-saturated with respect to the aqueous solution. The method is implemented for a simple prototype batch reactor using Mathematica for a binary solid solution. Finally, the sensitivity of the results on the kinetic rate constant for a binary solid solution is investigated for reaction of an initially stoichiometric solid phase with an undersaturated aqueous solution.

Study on radiation-induced deactivation and post-deactivation of some oxidoreductases in dilute aqueous solution and protective effect: Pt. 1

International Nuclear Information System (INIS)

Chen Yiqing; Ha Hongfei

1993-01-01

In this work the radiation-induced deactivation of catalase in dilute aqueous solution was reported. The effects of irradiation atmosphere, temperature and original concentration of catalase in dilute aqueous solutions on the deactivation of catalase were investigated. The protective effect by some additives (CH 3 CH 2 OH, HCOONa and EDTA) to radiation deactivation in dilute aqueous solutions was also studied. Remarkable protective effect by those additives was observed. The mechanism of radiation deactivation and protective effect have been discussed

On the attenuation of x-rays and gamma-rays in dilute solutions

DEFF Research Database (Denmark)

Gerward, Leif

1996-01-01

The theory of X-ray and gamma-ray attenuation in solutions is developed. The rule of mixture for the calculation of mass and linear attenuation coefficients is elaborated in the general case as well as in the limit of extreme dilution. The validity of the latter approximation is illustrated...... by the attenuation of 17.443 keV X-rays in aqueous solutions of NaCl. Copyright (C) 1996 Elsevier Science Ltd...

Effect of solute segregation on thermal creep in dilute nanocyrstalline Cu alloys

International Nuclear Information System (INIS)

Schäfer, Jonathan; Ashkenazy, Yinon; Albe, Karsten; Averback, Robert S

2012-01-01

Highlights: ► Segregating solutes lower the grain boundary free volume in nanocrystalline Cu. ► Lower free volume leads to reduced atomic mobility and higher creep resistance. ► Increase in creep resistance scales with atomic size of segregating solutes. ► Atomic processes in boundaries are similar to the ones in amorphous material. - Abstract: The effect of solute segregation on thermal creep in dilute nanocrystalline alloys (Cu–Nb, Cu–Fe, Cu–Zr) was studied at elevated temperatures using molecular dynamics simulations. A combined Monte-Carlo and molecular dynamics simulation technique was first used to equilibrate the distribution of segregating solutes. Then the creep rates of the diluted Cu samples were measured as functions of temperature, composition, load and accumulated strain. In Cu–Nb samples, the creep rates were observed to increase initially with strain, but then saturate at a value close to that obtained for alloys prepared by randomly locating the solute in the grain boundaries. This behavior is attributed to an increase in grain boundary volume and energy with added chemical disorder. At high temperatures, the apparent activation energy for creep was anomalously high, 3 eV, but only 0.3 eV at lower temperatures. This temperature dependence is found to correlate with atomic mobilities in bulk Cu–Nb glasses. Calculations of creep in nanocrystalline Cu alloys containing other solutes, Fe and Zr, show that the suppression of creep rate scales with their atomic volumes when dissolved in Cu.

Effective Microporosity for Enhanced Adsorption Capacity of Cr (VI) from Dilute Aqueous Solution: Isotherm and Kinetics

OpenAIRE

Lloyd Mukosha; Maurice S. Onyango; Aoyi Ochieng; John Siame

2017-01-01

The adsorbent pore structure significant to enhanced adsorption capacity of Cr (VI) from dilute aqueous solution is evaluated. As reference, low-cost micro-mesoporous activated carbon (AC) of high basicity, mesoporosity centred about 2.4 nm, and effective microporosity centred about 0.9 nm was tested for removal of Cr (VI) from dilute aqueous solution in batch mode. At pH 2 the low-cost AC exhibited highly improved Langmuir Cr (VI) capacity of 115 mg/g which was competitive to high performanc...

Superfluidity of a dilute 3He-4He solution

International Nuclear Information System (INIS)

Soda, Toshio

1993-01-01

The interaction between two 3 He atoms is calculated by taking into account the backflow effect of 3 He by the 4 He in the 3 He- 4 He mixture. The effect contributes solely to the P wave part of the interaction. The repulsive S wave part of the contact interaction contributes to the exchange interaction between the 3 He atoms, while the direct one phonon exchange interaction contributes both to the S and P wave attractive interactions. The overall contribution to the attractive interaction is dominated by the P wave part and the superfluidity in the P wave is more predominant than in the S wave for the 5 % dilute 3 He- 4 He solution, and vice versa for the 1.3 % solution. (author)

Method for Predicting Solubilities of Solids in Mixed Solvents

DEFF Research Database (Denmark)

Ellegaard, Martin Dela; Abildskov, Jens; O'Connell, J. P.

2009-01-01

A method is presented for predicting solubilities of solid solutes in mixed solvents, based on excess Henry's law constants. The basis is statistical mechanical fluctuation solution theory for composition derivatives of solute/solvent infinite dilution activity coefficients. Suitable approximatio...

Radiolysis of dilute aqueous solutions of cesium iodide

International Nuclear Information System (INIS)

Gorbovitskaya, T.I.; Galinkin, D.L.; Kants, L.K.; Tiliks, Yu.E.; Kotelkin, I.M.; Luzanova, L.M.

1993-01-01

Study of physical-chemical processes in the NPP containment by severe accident is carried out. Radiolysis of reactor cooling water containing iodine and cesium radionuclides penetrated therein in the course of accident is considered as of such processes. Role of ionizing radiation in the process of formation and release of ecologically hazardous volatile forms of radioiodine from reactor water into environment is studied. Experiments on radiolysis of CsI diluted water solutions are carried out. The data obtained were used for clarification of radiolysis mechanism for iodine-containing water system, enabling forecast of iodine behaviour in the course of the accident. 5 refs., 4 figs., 1 tab

Visualizing a dilute vortex liquid to solid phase transition in a Bi2Sr2CaCu2O8 single crystal

International Nuclear Information System (INIS)

Shaw, Gorky; Mandal, Pabitra; Banerjee, S S; Tamegai, T

2012-01-01

Using high-sensitivity magneto-optical imaging, we find evidence for a jump in local vortex density associated with a vortex liquid to vortex solid phase transition just above the lower critical field in a single crystal of Bi 2 Sr 2 CaCu 2 O 8 . We find that the regions of the sample where the jump in vortex density occurs are associated with low screening currents. In the field–temperature vortex phase diagram, we identify phase boundaries demarcating a dilute vortex liquid phase and the vortex solid phase. The phase diagram also identifies a coexistence regime of the dilute vortex liquid and solid phases and shows the effect of pinning on the vortex liquid to vortex solid phase transition line. We find that the phase boundary lines can be fitted to the theoretically predicted expression for the low-field portion of the phase boundary delineating a dilute vortex solid from a vortex liquid phase. We show that the same theoretical fit can be used to describe the pinning dependence of the low-field phase boundary lines provided that the dependence of the Lindemann number on pinning strength is considered. (paper)

Dynamics of dilute polymer solutions

International Nuclear Information System (INIS)

Nicholson, L.K.; Higgins, J.S.

1980-01-01

Neutrons scattered by nuclei undergoing slow motion e.g. the internal motion within polymer chains, lose or gain very small amounts of energy. It is therefore the quasi-elastic region of the neutron scattering spectrum which is of interest and in particular the time correlation function (or intermediate scattering law S(Q,t)) which is ideally required to define the motion. The neutron spin echo spectrometer (IN11) at the ILL facilitates the measurement of very small energy changes (down to 10 neV) on scattering from a sample, by changing and keeping track of neutron beam polarization non-parallel to the magnetic guide-field (1). The resultant neutron beam polarization, when normalized against a standard (totally elastic) scatterer is directly proportional to the cosine Fourier Transform of the scattering law S(Q,ω), which is to say the time correlation function is measured directly. Dilute solutions of deuterated polystyrene (PSD) and deuterated polytetrahydrofuran (PTDF) in carbon disulphide, and of their hydrogeneous counterparts (PSH and PTHF respectively) in deuterated benzene were investigated in the range 0.027 A -1 -1 , at 30 0 C. (orig./FKS)

Surface phase transitions in cu-based solid solutions

Science.gov (United States)

Zhevnenko, S. N.; Chernyshikhin, S. V.

2017-11-01

We have measured surface energy in two-component Cu-based systems in H2 + Ar gas atmosphere. The experiments on solid Cu [Ag] and Cu [Co] solutions show presence of phase transitions on the surfaces. Isotherms of the surface energy have singularities (the minimum in the case of copper solid solutions with silver and the maximum in the case of solid solutions with cobalt). In both cases, the surface phase transitions cause deficiency of surface miscibility: formation of a monolayer (multilayer) (Cu-Ag) or of nanoscale particles (Cu-Co). At the same time, according to the volume phase diagrams, the concentration and temperature of the surface phase transitions correspond to the solid solution within the volume. The method permits determining the rate of diffusional creep in addition to the surface energy. The temperature and concentration dependence of the solid solutions' viscosity coefficient supports the fact of the surface phase transitions and provides insights into the diffusion properties of the transforming surfaces.

Magnetic and electrical properties in BaNiS2-type solid solutions

International Nuclear Information System (INIS)

Irizawa, Akinori; Yoshimura, Kazuyoshi; Kosuge, Koji

2000-01-01

The magnetic and electrical properties are reported in the new solid solutions BaCo 1-x Cu x S 2 and BaNi 1-x Fe x S 2 . Both compounds show spin-glass-like behavior, although the type of spin frustrations is different with each other. BaCo 1-x Cu x S 2 shows a competition type spin-glass behavior with reentrant phenomenon from antiferromagnetic to spin-glass at low temperatures. BaNi 1-x Fe x S 2 shows a dilute type spin-glass behavior together with super-paramagnetic properties. The temperature variation of 57 Fe Moessbauer spectra in BaNi 0.8 Fe 0.2 S 2 is explicable in a framework of cluster-glass. (author)

Study of vibrational and magnetic excitations in NicMg1-cO solid solutions by Raman spectroscopy

International Nuclear Information System (INIS)

Cazzanelli, E; Kuzmin, A; Mariotto, G; Mironova-Ulmane, N

2003-01-01

The Raman scattering by phonons and magnons was studied for the first time in the polycrystalline solid solutions Ni c Mg 1-c O. The experimental Raman spectrum for c = 0.9 is similar to that of NiO and consists of six well resolved bands, whose origins are the disorder-induced one-phonon scattering (bands at 400 and 500 cm -1 ), two-phonon scattering (bands at 750, 900, and 1100 cm -1 ), and two-magnon scattering (the broad band at ∼ 1400 cm -1 ). We found that the dependence of the two-magnon band in solid solutions on the composition and temperature is consistent with their magnetic phase diagram. We also observed that the relative contribution of two-phonon scattering decreases strongly upon dilution with magnesium ions and disappears completely at c < 0.5. Such behaviour is explained in terms of a disorder-induced effect, which increases the probability of the one-phonon scattering processes

Phase stability in wear-induced supersaturated Al-Ti solid solution

Energy Technology Data Exchange (ETDEWEB)

Watanabe, Y.; Yokoyama, K. [Dept. of Functional Machinery Mechanics Shinshu Univ., Ueda (Japan); Hosoda, H. [Precision and Intelligence Lab., Tokyo Inst. of Tech., Nagatsuta, Midori-ku, Yokohama (Japan)

2002-07-01

Al-Ti supersaturated solid solutions were introduced by wear testing and the rapid quenching of an Al/Al{sub 3}Ti composite (part of an Al/Al{sub 3}Ti functionally graded material) that was fabricated using the centrifugal method. The phase stability of the supersaturated solid solution was studied through systematic annealing of the supersaturated solid solution. It was found that the Al-Ti supersaturated solid solution decomposed into Al and Al{sub 3}Ti intermetallic compound phases during the heat treatment. The Al-Ti supersaturated solid solutions fabricated were, therefore, not an equilibrium phase, and thus decomposed into the equilibrium phases during heat treatment. It was also found that heat treatment leads to a significant hardness increase for the Al-Ti supersaturated solid solution. Finally, it was concluded that formation of the wear-induced supersaturated solid solution layer was a result of severe plastic deformation. (orig.)

Solid solution hardening in face centered binary alloys: Gliding statistics of a dislocation in random solid solution by atomistic simulation

International Nuclear Information System (INIS)

Patinet, S.

2009-12-01

The glide of edge and screw dislocation in solid solution is modeled through atomistic simulations in two model alloys of Ni(Al) and Al(Mg) described within the embedded atom method. Our approach is based on the study of the elementary interaction between dislocations and solutes to derive solid solution hardening of face centered cubic binary alloys. We identify the physical origins of the intensity and range of the interaction between a dislocation and a solute atom. The thermally activated crossing of a solute atom by a dislocation is studied at the atomistic scale. We show that hardening of edge and screw segments are similar. We develop a line tension model that reproduces quantitatively the atomistic calculations of the flow stress. We identify the universality class to which the dislocation depinning transition in solid solution belongs. (author)

On-line double isotope dilution laser ablation inductively coupled plasma mass spectrometry for the quantitative analysis of solid materials.

Science.gov (United States)

Fernández, Beatriz; Rodríguez-González, Pablo; García Alonso, J Ignacio; Malherbe, Julien; García-Fonseca, Sergio; Pereiro, Rosario; Sanz-Medel, Alfredo

2014-12-03

We report on the determination of trace elements in solid samples by the combination of on-line double isotope dilution and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The proposed method requires the sequential analysis of the sample and a certified natural abundance standard by on-line IDMS using the same isotopically-enriched spike solution. In this way, the mass fraction of the analyte in the sample can be directly referred to the certified standard so the previous characterization of the spike solution is not required. To validate the procedure, Sr, Rb and Pb were determined in certified reference materials with different matrices, including silicate glasses (SRM 610, 612 and 614) and powdered samples (PACS-2, SRM 2710a, SRM 1944, SRM 2702 and SRM 2780). The analysis of powdered samples was carried out both by the preparation of pressed pellets and by lithium borate fusion. Experimental results for the analysis of powdered samples were in agreement with the certified values for all materials. Relative standard deviations in the range of 6-21% for pressed pellets and 3-21% for fused solids were obtained from n=3 independent measurements. Minimal sample preparation, data treatment and consumption of the isotopically-enriched isotopes are the main advantages of the method over previously reported approaches. Copyright © 2014 Elsevier B.V. All rights reserved.

Nonequilibrium thermodynamics of dilute polymer solutions in flow.

Science.gov (United States)

Latinwo, Folarin; Hsiao, Kai-Wen; Schroeder, Charles M

2014-11-07

Modern materials processing applications and technologies often occur far from equilibrium. To this end, the processing of complex materials such as polymer melts and nanocomposites generally occurs under strong deformations and flows, conditions under which equilibrium thermodynamics does not apply. As a result, the ability to determine the nonequilibrium thermodynamic properties of polymeric materials from measurable quantities such as heat and work is a major challenge in the field. Here, we use work relations to show that nonequilibrium thermodynamic quantities such as free energy and entropy can be determined for dilute polymer solutions in flow. In this way, we determine the thermodynamic properties of DNA molecules in strong flows using a combination of simulations, kinetic theory, and single molecule experiments. We show that it is possible to calculate polymer relaxation timescales purely from polymer stretching dynamics in flow. We further observe a thermodynamic equivalence between nonequilibrium and equilibrium steady-states for polymeric systems. In this way, our results provide an improved understanding of the energetics of flowing polymer solutions.

Prediction of thermodynamic properties of solute elements in Si solutions using first-principles calculations

International Nuclear Information System (INIS)

Iwata, K.; Matsumiya, T.; Sawada, H.; Kawakami, K.

2003-01-01

The method is presented to predict the activity coefficients and the interaction parameters of the solute elements in infinite dilute Si solutions by the use of first-principles calculations based on density functional theory. In this method, the regular solution model is assumed. The calculated activity coefficients in solid Si are converted to those in molten Si by the use of the solid-liquid partition coefficients. Furthermore, the interaction parameters in solid Si solutions are calculated and compared with reported experimental values of those in liquid Si solutions. The results show that the calculated activity coefficients and interaction parameters of Al, Fe, Ti and Pb in Si solutions are in good agreement with the tendency of the experiments. However, the calculations have some quantitative discrepancy from the experiments. It is expected that consideration of the excess entropy would reduce this discrepancy

Dilute-solution Structure of Charged Arborescent Graft Polymer

International Nuclear Information System (INIS)

Yun, Seok; Briber, R.M.; Kee, R. Andrew; Gauthier, Mario

2006-01-01

The solutions of charged G1 arborescent polystyrene-graft-poly(2-vinylpyridine) copolymers in methanol-d4 and D 2 O were investigated over a dilute concentration range φ = 0.005-0.05 (φ: mass fraction) using small-angle neutron scattering (SANS). Upon addition of acid (HCl) arborescent graft polymers became charged and a peak appeared in SANS data. The interparticle distance (d exp ) calculated from a peak position corresponded to the expected value (d uni ) for a uniform particle distribution. This indicates the formation of liquid-like ordering due to long-range Coulombic repulsions. The smaller dielectric constant of methanol-d4 resulted in long-range electrostatic repulsions persisting to lower polymer concentration than in D 2 O. The slow mode scattering was observed by dynamic light scattering measurements for the same polymer solutions, indicating the presence of structural inhomogeneity in the solutions. Both the peak and slow mode disappeared by addition of NaCl or excess HCl into the solutions due to the screening of electrostatic interactions. The G1 polymer grafted with longer P2VP chains (M w ∼ 30,000 versus 5000 g mol) formed a gel on addition of HCl. This result reveals that molecular expansion is more significant for arborescent polymers with longer (M w ∼ 30,000) linear polyelectrolyte branches, resulting in gelation for φ > 0.01. Upon addition of NaCl or excess HCl a gel transformed back to a liquid resulted from the screening of electrostatic interactions.

Thermotransport in interstitial solid solutions

International Nuclear Information System (INIS)

Fogel'son, R.L.

1982-01-01

On the basis of literature data the problem of thermotransport of impurities (H, N, O, C) in interstitial solid solutions is considered. It is shown that from experimental data on the thermotransport an important parameter of dissolved atoms can be found which characterizes atom state in these solutions-enthalpy of transport

Superhard Rhenium/Tungsten Diboride Solid Solutions.

Science.gov (United States)

Lech, Andrew T; Turner, Christopher L; Lei, Jialin; Mohammadi, Reza; Tolbert, Sarah H; Kaner, Richard B

2016-11-02

Rhenium diboride (ReB 2 ), containing corrugated layers of covalently bonded boron, is a superhard metallic compound with a microhardness reaching as high as 40.5 GPa (under an applied load of 0.49 N). Tungsten diboride (WB 2 ), which takes a structural hybrid between that of ReB 2 and AlB 2 , where half of the boron layers are planar (as in AlB 2 ) and half are corrugated (as in ReB 2 ), has been shown not to be superhard. Here, we demonstrate that the ReB 2 -type structure can be maintained for solid solutions of tungsten in ReB 2 with tungsten content up to a surprisingly large limit of nearly 50 atom %. The lattice parameters for the solid solutions linearly increase along both the a- and c-axes with increasing tungsten content, as evaluated by powder X-ray and neutron diffraction. From micro- and nanoindentation hardness testing, all of the compositions within the range of 0-48 atom % W are superhard, and the bulk modulus of the 48 atom % solid solution is nearly identical to that of pure ReB 2 . These results further indicate that ReB 2 -structured compounds are superhard, as has been predicted from first-principles calculations, and may warrant further studies into additional solid solutions or ternary compounds taking this structure type.

Dilute solutions and phase behavior of polydisperse A-b-(A-co-B) diblock copolymers

Czech Academy of Sciences Publication Activity Database

Gromadzki, Daniel; Lokaj, Jan; Šlouf, Miroslav; Štěpánek, Petr

2009-01-01

Roč. 50, č. 11 (2009), s. 2451-2459 ISSN 0032-3861 Institutional research plan: CEZ:AV0Z40500505 Keywords : diblock copolymer * dilute solution properties * microphase separation Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.573, year: 2009

Thermal diffusivity of samarium-gadolinium zirconate solid solutions

International Nuclear Information System (INIS)

Pan, W.; Wan, C.L.; Xu, Q.; Wang, J.D.; Qu, Z.X.

2007-01-01

We synthesized samarium-gadolinium zirconate solid solutions and determined their thermal diffusivities, Young's moduli and thermal expansion coefficients, which are very important for their application in thermal barrier coatings. Samarium-gadolinium zirconate solid solutions have extremely low thermal diffusivity between 20 and 600 deg. C. The solid solutions have lower Young's moduli and higher thermal expansion coefficients than those of pure samarium and gadolinium zirconates. This combination of characteristics is promising for the application of samarium and gadolinium zirconates in gas turbines. The mechanism of phonon scattering by point defects is discussed

Theoretical-experimental study of the solvation enthalpy of acetone in dilute aqueous solution

International Nuclear Information System (INIS)

Arroyo, S. Tolosa; Martin, J.A. Sanson; Garcia, A. Hidalgo

2005-01-01

The present paper describes molecular dynamics simulations of aqueous solutions at infinite dilution with acetone as solute. Lennard-Jones with electrostatic term (12-6-1 potentials) were employed to describe the solute-solvent interactions. The Morokuma decomposition scheme of ab initio interaction energies at the SCF level and the ESIE charges on the solute atoms were used to reproduce the exchange and Coulomb electrostatic contributions of the solute-water interaction potential. Some extensions, such as including the dispersion component evaluated at MP2 level, were added to the traditional calculation procedures in order to improve the results of the solvation enthalpy. The results obtained with the EX-DIS-ES model were compared with the experimental calorimetry values, the observed agreement being acceptable

Solid state synthesis, crystal growth and optical properties of urea and p-chloronitrobenzene solid solution

Energy Technology Data Exchange (ETDEWEB)

Rai, R.N., E-mail: rn_rai@yahoo.co.in [Department of Chemistry, Centre of Advanced Study, Banaras Hindu University, Varanasi 221005 (India); Kant, Shiva; Reddi, R.S.B. [Department of Chemistry, Centre of Advanced Study, Banaras Hindu University, Varanasi 221005 (India); Ganesamoorthy, S. [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102, Tamilnadu (India); Gupta, P.K. [Laser Materials Development & Devices Division, Raja Ramanna Centre for Advanced Technology, Indore 452013 (India)

2016-01-15

Urea is an attractive material for frequency conversion of high power lasers to UV (for wavelength down to 190 nm), but its usage is hindered due to its hygroscopic nature, though there is no alternative organic NLO crystal which could be transparent up to 190 nm. The hygroscopic character of urea has been modified by making the solid solution (UCNB) of urea (U) and p-chloronitrobenzene (CNB). The formation of the solid solution of CNB in U is explained on the basis of phase diagram, powder XRD, FTIR, elemental analysis and single crystal XRD studies. The solubility of U, CNB and UCNB in ethanol solution is evaluated at different temperatures. Transparent single crystals of UCNB are grown from its saturated solution in ethanol. Optical properties e.g., second harmonic generation (SHG), refractive index and the band gap for UCNB crystal were measured and their values were compared with the parent compounds. Besides modification in hygroscopic nature, UCNB has also shown the higher SHG signal and mechanical hardness in comparison to urea crystal. - Highlights: • The hygroscopic character of urea was modified by making the solid solution • Solid solution formation is support by elemental, powder- and single crystal XRD • Crystal of solid solution has higher SHG signal and mechanical stability. • Refractive index and band gap of solid solution crystal have determined.

Reverse osmosis performance of cellulose acetate membranes in the separation of uranium from dilute solutions

International Nuclear Information System (INIS)

Sastri, V.S.; Ashbrook, A.W.

1976-01-01

Batch 316-type cellulose acetate membranes were characterized in terms of pure water permeability constant, solute transport parameter, and mass transfer coefficient with a reference system of aqueous sodium chloride solution. These membranes were used in the determination of reverse osmosis characteristics such as product rate and solute separation in the case of uranium sulfate solutions of different concentrations (100 to 8000 ppM) in the feed solutions. A long-term test extending over a week has been carried out with dilute uranium solutions. Reverse osmosis treatment of synthetic mine water sample showed satisfactory performance of the membranes in the separation of metal ions

SOLISOL-handling of solid solutions. Version 1.1

International Nuclear Information System (INIS)

Boerjesson, S.; Emren, A.

1992-09-01

SOLISOL is a C computer program designed to model geochemical reactions involving solid solutions. The program searches equilibrium concentrations of the components in the aqueous phase and the solid solution given by limited quantities of the solid solution components. The equilibrium code PHREEQE is used as a subprogram in SOLISOL. Subprograms external to PHREEQE extract information from PHREEQE results, take care of conserved properties, calculate solubilities and produce inputdata for PHREEQE. The essential idea in this process is to calculate solubilities for the components in terms of saturation indices, and give directions to PHREEQE on how to search for the equilibrium under those constraints. (au)

Diluting ferric carboxymaltose in sodium chloride infusion solution (0.9% w/v) in polypropylene bottles and bags: effects on chemical stability.

Science.gov (United States)

Philipp, Erik; Braitsch, Michaela; Bichsel, Tobias; Mühlebach, Stefan

2016-01-01

This study was designed to assess the physicochemical stability of colloidal ferric carboxymaltose solution (Ferinject) when diluted and stored in polypropylene (PP) bottles and bags for infusion. Two batches of ferric carboxymaltose solution (Ferinject) were diluted (500 mg, 200 mg and 100 mg iron in 100 mL saline) in PP bottles or bags under aseptic conditions. The diluted solutions were stored at 30°C and 75%±5% relative humidity (rH) for 72 h, and samples were withdrawn aseptically at preparation and after 24 h, 48 h and 72 h. Multiple parameters were used to test stability-related measures (pH, total iron and iron (II) content, molecular weight range determination, microbial contamination and particles count ≥10 μm). Overall, Ferinject diluted in 0.9% (w/v) NaCl solution and stored in PP bottles and bags was stable within the specifications for the complex and the acceptability limits set for all assays. In both containers, total iron content remained stable, within 10% of the theoretical iron content, and levels of iron (II) remained far below the threshold of acceptability. All preparations were free from sediments, particle numbers were acceptable and there was no microbial contamination. The molecular weight distribution and polydispersity index were also acceptable. Under the tested experimental conditions, colloidal ferric carboxymaltose solution (Ferinject) diluted in saline in PP infusion bottles or bags demonstrated physical and chemical stability for up to 72 h at 30°C and 75% rH. Because of the lack of additional clinical data, when using ferric carboxymaltose, physicians/pharmacists should refer to the dilution and storing recommendations given in the product's summary of product characteristics.

Gamma-radiolysis of some glycoproteins in dilute aqueous solutions

Energy Technology Data Exchange (ETDEWEB)

Nagrani, S

1981-01-01

A study has been made of the radiation-induced damage of some glycoproteins in dilute aqueous solutions. By use of specific radical scavengers, the roles of the individual free radicals, formed by ..gamma..-radiolysis, in causing damage has been assessed. The most effective radical in causing damage to human and porcine glycopolypeptide is the OH radical. The structure of the different blood group glycopolypeptides determines the sensitivity towards the free radical attack. The glycopolypeptide shows depolymerization and a characteristic absorption at approximately 270 nm due to the formation of additional products on irradiation. Chemical changes of the irradiated glycopolypeptide solutions revealed significant damage to the oligosaccharide chain and the polypeptide core of the glycopolypeptide. The radiation-induced inactivation of another glycoprotein, external yeast invertase, due to different radical species at pH 7.0 decreases in the following order: ea-barq > OH radical > (SCN) radical/sub 2//sup -/ > Br radical/sub 2//sup -/. The structure of this enzyme, accounts for the mechanism of enzyme inactivation and the relative damage of carbohydrate and amino acid residues. The irradiated enzyme solutions show significant changes in their electrophoretic behaviour on cellogel electrophoresis due to the formation of radiolysis products, which also show characteristic absorption maxima at approximately 275 nm. (author).

Laboratory studies of 2H evaporator scale dissolution in dilute nitric acid

International Nuclear Information System (INIS)

Oji, L.

2014-01-01

The rate of 2H evaporator scale solids dissolution in dilute nitric acid has been experimentally evaluated under laboratory conditions in the SRNL shielded cells. The 2H scale sample used for the dissolution study came from the bottom of the evaporator cone section and the wall section of the evaporator cone. The accumulation rate of aluminum and silicon, assumed to be the two principal elemental constituents of the 2H evaporator scale aluminosilicate mineral, were monitored in solution. Aluminum and silicon concentration changes, with heating time at a constant oven temperature of 90 deg C, were used to ascertain the extent of dissolution of the 2H evaporator scale mineral. The 2H evaporator scale solids, assumed to be composed of mostly aluminosilicate mineral, readily dissolves in 1.5 and 1.25 M dilute nitric acid solutions yielding principal elemental components of aluminum and silicon in solution. The 2H scale dissolution rate constant, based on aluminum accumulation in 1.5 and 1.25 M dilute nitric acid solution are, respectively, 9.21E-04 ± 6.39E-04 min -1 and 1.07E-03 ± 7.51E-05 min -1 . Silicon accumulation rate in solution does track the aluminum accumulation profile during the first few minutes of scale dissolution. It however diverges towards the end of the scale dissolution. This divergence therefore means the aluminum-to-silicon ratio in the first phase of the scale dissolution (non-steady state conditions) is different from the ratio towards the end of the scale dissolution. Possible causes of this change in silicon accumulation in solution as the scale dissolution progresses may include silicon precipitation from solution or the 2H evaporator scale is a heterogeneous mixture of aluminosilicate minerals with several impurities. The average half-life for the decomposition of the 2H evaporator scale mineral in 1.5 M nitric acid is 12.5 hours, while the half-life for the decomposition of the 2H evaporator scale in 1.25 M nitric acid is 10.8 hours

Phase separation in solution of worm-like micelles: a dilute ? spin-vector model

Science.gov (United States)

Panizza, Pascal; Cristobal, Galder; Curély, Jacques

1998-12-01

We show how the dilute 0953-8984/10/50/006/img2 spin vector model introduced originally by Wheeler and co-workers for describing the polymerization phenomenon in solutions of liquid sulphur and of living polymers may be conveniently adapted for studying phase separation in systems containing long flexible micelles. We draw an isomorphism between the coupling constant appearing in the exchange Hamiltonian and the surfactant energies in the micellar problem. We solve this problem within the mean-field approximation and compare the main results we have obtained with respect to polymer theory and previous theories of phase separation in micellar solutions. We show that the attractive interaction term 0953-8984/10/50/006/img3 between monomers renormalizes the aggregation energy and subsequently the corresponding size distribution. Under these conditions, we observe that the general aspect of the phase diagram in the 0953-8984/10/50/006/img4 plane (where 0953-8984/10/50/006/img5 is the surfactant concentration) is different from previous results. The spinodal line shows a re-entrant behaviour and, at low concentrations, we point out the possibility of specific nucleation phenomena related to the existence of a metastable transition line between a region composed of spherical micelles and another one corresponding to a dilute solution of long flexible micelles.

L'infiltration d'une dilution ideale des solutions avec epineph rine au ...

African Journals Online (AJOL)

L'auteur rapporte un procédé simplifié de dilution d'une solution anesthésique avec épinéphrine passant d'une concentration de 1/100 000 à 1/800 000 pour rechercher une hémostase locale effective sans compromettre dans l'immédiat la vitalité de la vascularisation périphérique des lambeaux cutanés levés. The author ...

Phase Behaviour and Miscibility Studies of Collagen/Silk Fibroin Macromolecular System in Dilute Solutions and Solid State.

Science.gov (United States)

Ghaeli, Ima; de Moraes, Mariana A; Beppu, Marisa M; Lewandowska, Katarzyna; Sionkowska, Alina; Ferreira-da-Silva, Frederico; Ferraz, Maria P; Monteiro, Fernando J

2017-08-18

Miscibility is an important issue in biopolymer blends for analysis of the behavior of polymer pairs through the detection of phase separation and improvement of the mechanical and physical properties of the blend. This study presents the formulation of a stable and one-phase mixture of collagen and regenerated silk fibroin (RSF), with the highest miscibility ratio between these two macromolecules, through inducing electrostatic interactions, using salt ions. For this aim, a ternary phase diagram was experimentally built for the mixtures, based on observations of phase behavior of blend solutions with various ratios. The miscibility behavior of the blend solutions in the miscible zones of the phase diagram was confirmed quantitatively by viscosimetric measurements. Assessing the effects of biopolymer mixing ratio and salt ions, before and after dialysis of blend solutions, revealed the importance of ion-specific interactions in the formation of coacervate-based materials containing collagen and RSF blends that can be used in pharmaceutical, drug delivery, and biomedical applications. Moreover, the conformational change of silk fibroin from random coil to beta sheet, in solution and in the final solid films, was detected by circular dichroism (CD) and Fourier transform infrared spectroscopy (FTIR), respectively. Scanning electron microscopy (SEM) exhibited alterations of surface morphology for the biocomposite films with different ratios. Surface contact angle measurement illustrated different hydrophobic properties for the blended film surfaces. Differential scanning calorimetry (DSC) showed that the formation of the beta sheet structure of silk fibroin enhances the thermal stability of the final blend films. Therefore, the novel method presented in this study resulted in the formation of biocomposite films whose physico-chemical properties can be tuned by silk fibroin conformational changes by applying different component mixing ratios.

An assessment of the dilution required to mitigate Hanford tank 241-SY-101

International Nuclear Information System (INIS)

Hudson, J.D.; Bredt, P.R.; Felmy, A.R.; Stewart, C.W.; Tingey, J.M.; Trent, D.S.; Barney, G.S.; Herting, D.L.; Larrick, A.P.; Reynolds, D.A.

1995-02-01

A group of experts from PNL and WHC convened November 2 and 3, 1994, to screen the current state of knowledge about dilution and reach a consensus on the minimum dilution ratio that will achieve passive mitigation of Tank 241-SY-101 wastes and the dilution ratio that would satisfy the given cross-site transfer criteria with reasonable assurance. The panel evaluated the effects of dilution on the parameters important in gas generation, retention, and release and reached the following conclusions, which are deduced from the existing body of data, experience, and analyses: (1) Dissolution of solids is the single most important aspect of mitigation by dilution. We are confident that diluting until nitrates, nitrites, and aluminum salts are dissolved will mitigate Hanford flammable gas tanks; (2) Sufficient solids dissolution can be achieved in Tank 241-SY-101 at a dilution ratio of 1:1, which will result in a average specific gravity of approximately 1.35. It is likely that a 0.5:1 dilution will also mitigate 241-SY-101, but the current uncertainty is too high to recommend this dilution ratio; (3) The recommended dilution requires a diluent with at least 2 molar free hydroxide, because aluminum probably precipitates at lower hydroxide concentrations. The transfer criteria for Tank 241-SY-101 waste were also evaluated. These criteria have been specified as solids content ≤30% (volume), viscosity ≤30% cP and density <1.5 g/mL. (1) Solids content is the limiting criterion if it is defined as volume fraction of settled solids. A 1:1 dilution will satisfy this criterion at nominal premixing conditions in Tank 241-SY-101; however, analysis of Window E core samples suggests that up to 1.5:1 might be required. If the solids content is interpreted simply as solids volume fraction no further dilution is necessary, because Tank 241-SY-101 waste (excluding the crust) is already below 30%; (2) Bulk density is the next limiting criterion and is met at 0.4:1 dilution

Enthalpy of dilution and volumetric properties of N-glycylglycine in aqueous xylitol solutions at T = 298.15 K

Energy Technology Data Exchange (ETDEWEB)

Liu Min, E-mail: panpanliumin@163.co [College of Chemistry and Chemical Engineering, Liao Cheng University, Liaocheng, Shandong 252059 (China); Wang Lili; Li Guangqian; Dong Lina; Sun Dezhi [College of Chemistry and Chemical Engineering, Liao Cheng University, Liaocheng, Shandong 252059 (China); Zhu Lanying [College of Life Science and Bioengineering, Liao Cheng University, Liaocheng, Shandong 252059 (China); Di Youying [College of Chemistry and Chemical Engineering, Liao Cheng University, Liaocheng, Shandong 252059 (China)

2011-06-15

Highlights: Enthalpies of dilution of N-glycylglycine in aqueous xylitol solutions were determined at 298.15 K. The homogeneous enthalpic interaction coefficients were calculated. Apparent molar volumes of the ternary systems were calculated from the data of densities. Limiting partial molar volumes and limiting partial molar volumes of transfer were deduced. - Abstract: The enthalpy of dilution of N-glycylglycine ({Delta}{sub dil}H{sub m}) in aqueous xylitol solutions has been determined by means of flow-mix isothermal microcalorimetry at the temperature of 298.15 K. The homogeneous enthalpic interaction coefficients (h{sub 2}, h{sub 3}, and h{sub 4}) which characterize the interactions of examined N-glycylglycine in aqueous xylitol solutions have been calculated according to the excess enthalpy concept based on the values of dilution enthalpy. It has been found that the enthalpic pair interaction coefficients (h{sub 2}) in the systems investigated are negative and become less negative as the molality of xylitol increases. Values of the density ({rho}) of the ternary homogeneous systems were also measured with a quartz vibrating-tube densimeter at the temperature of 298.15 K. The values of the apparent molar volume (V{sub {phi}}) of the ternary systems were calculated from the data of density, which have been used to deduce limiting partial molar volumes of N-glycylglycine (V{sub {phi}}{sup o}) and limiting partial molar volumes of transfer ({Delta}{sub trs}V{sub {phi}}{sup o}) from water to aqueous xylitol solutions at different concentrations. The results have been discussed based on solute-solute interactions and solvation effects.

Enthalpy of dilution and volumetric properties of N-glycylglycine in aqueous xylitol solutions at T = 298.15 K

International Nuclear Information System (INIS)

Liu Min; Wang Lili; Li Guangqian; Dong Lina; Sun Dezhi; Zhu Lanying; Di Youying

2011-01-01

Highlights: → Enthalpies of dilution of N-glycylglycine in aqueous xylitol solutions were determined at 298.15 K. → The homogeneous enthalpic interaction coefficients were calculated. → Apparent molar volumes of the ternary systems were calculated from the data of densities. → Limiting partial molar volumes and limiting partial molar volumes of transfer were deduced. - Abstract: The enthalpy of dilution of N-glycylglycine (Δ dil H m ) in aqueous xylitol solutions has been determined by means of flow-mix isothermal microcalorimetry at the temperature of 298.15 K. The homogeneous enthalpic interaction coefficients (h 2 , h 3 , and h 4 ) which characterize the interactions of examined N-glycylglycine in aqueous xylitol solutions have been calculated according to the excess enthalpy concept based on the values of dilution enthalpy. It has been found that the enthalpic pair interaction coefficients (h 2 ) in the systems investigated are negative and become less negative as the molality of xylitol increases. Values of the density (ρ) of the ternary homogeneous systems were also measured with a quartz vibrating-tube densimeter at the temperature of 298.15 K. The values of the apparent molar volume (V φ ) of the ternary systems were calculated from the data of density, which have been used to deduce limiting partial molar volumes of N-glycylglycine (V φ o ) and limiting partial molar volumes of transfer (Δ trs V φ o ) from water to aqueous xylitol solutions at different concentrations. The results have been discussed based on solute-solute interactions and solvation effects.

Stern potential and Debye length measurements in dilute ionic solutions with electrostatic force microscopy.

Science.gov (United States)

Kumar, Bharat; Crittenden, Scott R

2013-11-01

We demonstrate the ability to measure Stern potential and Debye length in dilute ionic solution with atomic force microscopy. We develop an analytic expression for the second harmonic force component of the capacitive force in an ionic solution from the linearized Poisson-Boltzmann equation. This allows us to calibrate the AFM tip potential and, further, obtain the Stern potential of sample surfaces. In addition, the measured capacitive force is independent of van der Waals and double layer forces, thus providing a more accurate measure of Debye length.

Hot 56Mn reactions in permanganate solutions: a quasi solution state study [Paper No. NC-6

International Nuclear Information System (INIS)

Dedgaonkar, V.G.; Mitra, S.

1982-01-01

Neutron activation of aqueous solutions of transition metal and ammonium permanganates over the concentration range 1-10 -3 M has been performed. Retentions for concentrated solutions were much higher than the solid state values, and upon dilution, a limiting value of approx. 4 per cent was attained. Activation of 1-10 -1 M permanganate quasi solutions containing either alumina or a polystyrene cation exchanger allowed continuous extraction of the recoil species before their recombination. (author)

Studies of Electrolytic Conductivity of Some Polyelectrolyte Solutions: Importance of the Dielectric Friction Effect at High Dilution

Directory of Open Access Journals (Sweden)

Anis Ghazouani

2013-01-01

Full Text Available We present a general description of conductivity behavior of highly charged strong polyelectrolytes in dilute aqueous solutions taking into account the translational dielectric friction on the moving polyions modeled as chains of charged spheres successively bounded and surrounded by solvent molecules. A general formal limiting expression of the equivalent conductivity of these polyelectrolytes is presented in order to distinguish between two concentration regimes and to evaluate the relative interdependence between the ionic condensation effect and the dielectric friction effect, in the range of very dilute solutions for which the stretched conformation is favored. This approach is illustrated by the limiting behaviors of three polyelectrolytes (sodium heparinate, sodium chondroitin sulfate, and sodium polystyrene sulphonate characterized by different chain lengths and by different discontinuous charge distributions.

Dermal absorption of a dilute aqueous solution of malathion

Directory of Open Access Journals (Sweden)

Scharf John

2008-01-01

Full Text Available Malathion is an organophosphate pesticide commonly used on field crops, fruit trees, livestock, agriculture, and for mosquito and medfly control. Aerial applications can result in solubilized malathion in swimming pools and other recreational waters that may come into contact with human skin. To evaluate the human skin absorption of malathion for the assessment of risk associated with human exposures to aqueous solutions, human volunteers were selected and exposed to aqueous solutions of malathion. Participants submerged their arms and hands in twenty liters of dilute malathion solution in either a stagnant or stirred state. The "disappearance method" was applied by measuring malathion concentrations in the water before and after human exposure for various periods of time. No measurable skin absorption was detected in 42% of the participants; the remaining 58% of participants measured minimal absorbed doses of malathion. Analyzing these results through the Hazard Index model for recreational swimmer and bather exposure levels typically measured in contaminated swimming pools and surface waters after bait application indicated that these exposures are an order of magnitude less than a minimal dose known to result in a measurable change in acetylcholinesterase activity. It is concluded that exposure to aqueous malathion in recreational waters following aerial bait applications is not appreciably absorbed, does not result in an effective dose, and therefore is not a public health hazard.

Stern potential and Debye length measurements in dilute ionic solutions with electrostatic force microscopy

International Nuclear Information System (INIS)

Kumar, Bharat; Crittenden, Scott R

2013-01-01

We demonstrate the ability to measure Stern potential and Debye length in dilute ionic solution with atomic force microscopy. We develop an analytic expression for the second harmonic force component of the capacitive force in an ionic solution from the linearized Poisson–Boltzmann equation. This allows us to calibrate the AFM tip potential and, further, obtain the Stern potential of sample surfaces. In addition, the measured capacitive force is independent of van der Waals and double layer forces, thus providing a more accurate measure of Debye length. (paper)

Fabrication and Application of (1-x) NaCl+xKCl Solid Solution

International Nuclear Information System (INIS)

Kyi Kyi Lwin

2011-12-01

(1-X)NaCl+xKCl solid solution are prepared by the starting materials NaCl (0.9, 0.95) in equal molar ratio. The solid solutions are heat-treated at various temperature and XRD analyses are carried out for the solid solutions to examine the crystalline phase, crystallographic orientation and lattice parameters. The electrical properties of the solutions are determined by using the conductometer. The solid solutions are utilized as crystal oscillator and outcoming frequencies, capacitances and dielectric constants are also investigated.

Solubility and hydrolysis of Np(V) in dilute to concentrated alkaline NaCl solutions. Formation of Na-Np(V)-OH solid phases at 22 C

Energy Technology Data Exchange (ETDEWEB)

Petrov, Vladimir G. [Lomonosov Moscow State Univ. (Russian Federation). Dept. of Chemistry; Fellhauer, David; Gaona, Xavier; Dardenne, Kathy; Rothe, Joerg; Altmaier, Marcus [Karlsruhe Institute of Technology (Germany). Inst. for Nuclear Waste Disposal; Kalmykov, Stepan N. [Lomonosov Moscow State Univ. (Russian Federation). Dept. of Chemistry; NRC Kurchatov Institute, Moscow (Russian Federation)

2017-03-01

The solubility of Np(V) was investigated at T=22±2 C in alkaline NaCl solutions of different ionic strength (0.1-5.0 M). The solid phases controlling the solubility at different -log{sub 10} m{sub H{sup +}}(pH{sub m}) and NaCl concentration were characterized by XRD, quantitative chemical analysis, SEM-EDS and XAFS (both XANES and EXAFS). Aqueous phases in equilibrium with Np(V) solids were investigated for selected samples within 8.9≤pH{sub m}≤10.3 by UV-vis/NIR absorption spectroscopy. In 0.1 M NaCl, the experimental solubility of the initial greenish NpO{sub 2}OH(am) solid phase is in good agreement with previous results obtained in NaClO{sub 4} solutions, and is consistent with model calculations for fresh NpO{sub 2}OH(am) using the thermodynamic data selection in NEA-TDB. Below pH{sub m}∝11.5 and for all NaCl concentrations studied, Np concentration in equilibrium with the solid phase remained constant during the timeframe of this study (∝2 years). This observation is in contrast to the aging of the initial NpO{sub 2}OH(am) into a more crystalline modification with the same stoichiometry, NpO{sub 2}OH(am, aged), as reported in previous studies for concentrated NaClO{sub 4} and NaCl. Instead, the greenish NpO{sub 2}OH(am) transforms into a white solid phase in those systems with [NaCl]≥1.0 M and pH{sub m}≥11.5, and into two different pinkish phases above pH{sub m}∝13.2. The solid phase transformation is accompanied by a drop in Np solubility of 0.5-2 log{sub 10}-units (depending upon NaCl concentration). XANES analyses of green, white and pink phases confirm the predominance of Np(V) in all cases. Quantitative chemical analysis shows the incorporation of Na{sup +} in the original NpO{sub 2}OH(am) material, with Na:Np ≤ 0.3 for the greenish solids and 0.8 ≤ Na:Np ≤ 1.6 for the white and pinkish phases. XRD data confirms the amorphous character of the greenish phase, whereas white and pink solids show well-defined but discrepant XRD patterns

The thermodynamics and kinetics of interstitial solid solutions

International Nuclear Information System (INIS)

Silva, J.R.G. da.

1976-04-01

Studies of hydrogen metal systems where the hidrogen is disolved in a solid solution are presented. Particular items of interest are: the thermodynamics of the hydrogen-iron system; the solubility of hidrogen in super pure iron single crytals; the thermodinamic functions of hydrogen in solid solutions of Nb, Ta and V; and the solubility of hydrogen in α-manganese. The diffusion of carbon and nitrogen in BCC iron is also studied

Prediction of activity coefficients at infinite dilution for organic solutes in ionic liquids by artificial neural network

Energy Technology Data Exchange (ETDEWEB)

Nami, Faezeh [Department of Chemistry, Shahid Beheshti University, G.C., Evin-Tehran 1983963113 (Iran, Islamic Republic of); Deyhimi, Farzad, E-mail: f-deyhimi@sbu.ac.i [Department of Chemistry, Shahid Beheshti University, G.C., Evin-Tehran 1983963113 (Iran, Islamic Republic of)

2011-01-15

To our knowledge, this work illustrates for the first time the ability of artificial neural network (ANN) to predict activity coefficients at infinite dilution for organic solutes in ionic liquids (ILs). Activity coefficient at infinite dilution ({gamma}{sup {infinity}}) is a useful parameter which can be used for the selection of effective solvent in the separation processes. Using a multi-layer feed-forward network with Levenberg-Marquardt optimization algorithm, the resulting ANN model generated activity coefficient at infinite dilution data over a temperature range of 298 to 363 K. The unavailable input data concerning softness (S) of organic compounds (solutes) and dipole moment ({mu}) of ionic liquids were calculated using GAMESS suites of quantum chemistry programs. The resulting ANN model and its validation are based on the investigation of up to 24 structurally different organic compounds (alkanes, alkenes, alkynes, cycloalkanes, aromatics, and alcohols) in 16 common imidazolium-based ionic liquids, at different temperatures within the range of 298 to 363 K (i.e. a total number of 914 {gamma}{sub Solute}{sup {infinity}}for each IL data point). The results show a satisfactory agreement between the predicted ANN and experimental data, where, the root mean square error (RMSE) and the determination coefficient (R{sup 2}) of the designed neural network were found to be 0.103, 0.996 for training data and 0.128, 0.994 for testing data, respectively.

Prediction of activity coefficients at infinite dilution for organic solutes in ionic liquids by artificial neural network

International Nuclear Information System (INIS)

Nami, Faezeh; Deyhimi, Farzad

2011-01-01

To our knowledge, this work illustrates for the first time the ability of artificial neural network (ANN) to predict activity coefficients at infinite dilution for organic solutes in ionic liquids (ILs). Activity coefficient at infinite dilution (γ ∞ ) is a useful parameter which can be used for the selection of effective solvent in the separation processes. Using a multi-layer feed-forward network with Levenberg-Marquardt optimization algorithm, the resulting ANN model generated activity coefficient at infinite dilution data over a temperature range of 298 to 363 K. The unavailable input data concerning softness (S) of organic compounds (solutes) and dipole moment (μ) of ionic liquids were calculated using GAMESS suites of quantum chemistry programs. The resulting ANN model and its validation are based on the investigation of up to 24 structurally different organic compounds (alkanes, alkenes, alkynes, cycloalkanes, aromatics, and alcohols) in 16 common imidazolium-based ionic liquids, at different temperatures within the range of 298 to 363 K (i.e. a total number of 914 γ Solute ∞ for each IL data point). The results show a satisfactory agreement between the predicted ANN and experimental data, where, the root mean square error (RMSE) and the determination coefficient (R 2 ) of the designed neural network were found to be 0.103, 0.996 for training data and 0.128, 0.994 for testing data, respectively.

Separation of glycols from dilute aqueous solutions via complexation with boronic acids

Energy Technology Data Exchange (ETDEWEB)

Randel, L.A.; King, C.J.

1991-07-01

This work examines methods of separating low molecular weight glycols from dilute aqueous solution. Extraction into conventional solvents is generally not economical, since, in the literature reviewed, distribution ratios for the two- to four-carbon glycols are all less than one. Distribution ratios can be increased, however, by incorporating into the organic phase an extracting agent that will complex with the solute of interest. The extracting agent investigated in this work is 3-nitrophenylboronic acid (NPBA). NPBA, a boric acid derivative, reversibly complexes with many glycols. The literature on complexation of borate and related compounds with glycols, including mechanistic data, measurement techniques, and applications to separation processes, provides information valuable for designing experiments with NPBA and is reviewed herein. 88 refs., 15 figs., 24 tabs.

Determinação do coeficiente de atividade na diluição infinita (g¥ através da micro-extração em fase sólida (SPME Determination of activity coefficients at infinite dilution through solid phase microextraction (SPME

Directory of Open Access Journals (Sweden)

Douglas B. Fonseca

2007-01-01

Full Text Available In this study a new approach, solid phase micro extraction (SPME, is used in the evaluation of the infinite dilution activity coefficient of the solute in a given solvent. It is the purpose of the current work to demonstrate a different approach to obtain the data needed for studying the solution thermodynamics of binary liquid mixtures as well as for designing multi-component separations. The solutes investigated at the temperature 298.15 K were toluene, ethyl benzene and xylene in the solvent methanol.

Increase in Ice Nucleation Efficiency of Feldspars, Kaolinite and Mica in Dilute NH3 and NH4+-containing Solutions

Science.gov (United States)

Kumar, A.; Marcolli, C.; Luo, B.; Krieger, U. K.; Peter, T.

2017-12-01

Semivolatile species present in the atmosphere are prone to adhere to mineral dust particle surfaces during long range transport, and could potentially change the particle surface properties and its ice nucleation (IN) efficiency. Immersion freezing experiments were performed with microcline (K-feldspar), known to be highly IN active, suspended in aqueous solutions of ammonia, (NH4)2SO4, NH4HSO4, NH4NO3, NH4Cl, Na2SO4, H2SO4, K2SO4 and KCl to investigate the effect of solutes on the IN efficiency. Freezing of emulsified droplets investigated with a differential scanning calorimeter (DSC) showed that the heterogeneous ice nucleation temperatures deviate from the water activity-based IN theory, describing heterogeneous ice nucleation temperatures as a function of solution water activity by a constant offset with respect to the ice melting point curve (Zobrist et al. 2008). IN temperatures enhanced up to 4.5 K were observed for very dilute NH3 and NH4+-containing solutions while a decrease was observed as the concentration was further increased. For all solutes with cations other than NH4+, the IN efficiency decreased. An increase of the IN efficiency in very dilute NH3 and NH4+-containing solutions followed by a decrease with increasing concentration was also observed for sanidine (K-feldspar) and andesine (Na/Ca-feldspar). This is an important indication towards specific chemical interactions between solutes and the feldspar surface which is not captured by the water activity-based IN theory. A similar trend is present but less pronounced in case of kaolinite and mica, while quartz is barely affected. We hypothesize that the hydrogen bonding of NH3 molecules with surface -OH groups could be the reason for the enhanced freezing temperatures in dilute ammonia and ammonium containing solutions as they could form an ice-like overlayer providing hydrogen bonding groups for ice to nucleate on top of it. This implies to possibilities of enhanced IN efficiency, especially

Heterogeneous Ferroelectric Solid Solutions Phases and Domain States

CERN Document Server

Topolov, Vitaly

2012-01-01

The book deals with perovskite-type ferroelectric solid solutions for modern materials science and applications, solving problems of complicated heterophase/domain structures near the morphotropic phase boundary and applications to various systems with morphotropic phases. In this book domain state–interface diagrams are presented for the interpretation of heterophase states in perovskite-type ferroelectric solid solutions. It allows to describe the stress relief in the presence of polydomain phases, the behavior of unit-cell parameters of coexisting phases and the effect of external electric fields. The novelty of the book consists in (i) the first systematization of data about heterophase states and their evolution in ferroelectric solid solutions (ii) the general interpretation of heterophase and domain structures at changing temperature, composition or electric field (iii) the complete analysis of interconnection domain structures, unit-cell parameters changes, heterophase structures and stress relief.

Dilution physics modeling: Dissolution/precipitation chemistry

International Nuclear Information System (INIS)

Onishi, Y.; Reid, H.C.; Trent, D.S.

1995-09-01

This report documents progress made to date on integrating dilution/precipitation chemistry and new physical models into the TEMPEST thermal-hydraulics computer code. Implementation of dissolution/precipitation chemistry models is necessary for predicting nonhomogeneous, time-dependent, physical/chemical behavior of tank wastes with and without a variety of possible engineered remediation and mitigation activities. Such behavior includes chemical reactions, gas retention, solids resuspension, solids dissolution and generation, solids settling/rising, and convective motion of physical and chemical species. Thus this model development is important from the standpoint of predicting the consequences of various engineered activities, such as mitigation by dilution, retrieval, or pretreatment, that can affect safe operations. The integration of a dissolution/precipitation chemistry module allows the various phase species concentrations to enter into the physical calculations that affect the TEMPEST hydrodynamic flow calculations. The yield strength model of non-Newtonian sludge correlates yield to a power function of solids concentration. Likewise, shear stress is concentration-dependent, and the dissolution/precipitation chemistry calculations develop the species concentration evolution that produces fluid flow resistance changes. Dilution of waste with pure water, molar concentrations of sodium hydroxide, and other chemical streams can be analyzed for the reactive species changes and hydrodynamic flow characteristics

[Effect of 60Co gamma-irradiation on dilute aqueous solutions of surfactants].

Science.gov (United States)

Sawai, T; Shimokowa, T; Miki, Y; Oseko, K; Sawai, T

1978-01-01

Present work deals with the effects of gamma irradiation from 60Co gamma-ray source upon aqueous solutions of three kinds of surfactants. When dilute aqueous solutions of sodium dodecyl sulfate (SDS, anionic), cethyl trimethyl ammonium chloride (CTAC, cationic), and polyoxyethylene lauryl ether (POE, non-ionic) were irradiated with gamma-rays at a room remperature, the residual concentration, products, surface tension, and forming power were examined by colorimetric method, IR spectrophotometric method, gaschromatography, Ross-Miles method, and Traube's stalagnometer etc.. These surfactants were decomposed by the irradiation and thus the surface tension increased and the forming power, on the contrary, decreased with dose. Radiation chemical yields (G-value) of the degradation were about 1 for the solutions of SDS and CTAC, and about 0.3 for the POE solution. From the experimental results, it was found that following chemical reactions seem to occur followed by the radiolysis of water; a) bond cleavage of ester for SDS, of CN for CTAC, and of oxyethylene for POE, b) hydrogen abstraction from the surfactants, c) production of CO bond in the presence of dissolved oxygen.

Structural analysis and magnetic properties of solid solutions of Co–Cr system obtained by mechanical alloying

International Nuclear Information System (INIS)

Betancourt-Cantera, J.A.; Sánchez-De Jesús, F.; Bolarín-Miró, A.M.; Betancourt, I.; Torres-Villaseñor, G.

2014-01-01

In this paper, a systematic study on the structural and magnetic properties of Co 100−x Cr x alloys (0 1−x Cr x (0 2 /kg) for the Co 90 Cr 10 , which decreases with the increasing of the Cr content up to x=80, as a consequence of the dilution effect of the magnetic moment which is caused by the Cr content and by the competition between ferromagnetic and antiferromagnetic exchange interactions. The coercivity increases up to 34 kA/m (435 Oe) for Co 40 Cr 60 . For Cr rich compositions, it is observed an important decrease reaching 21 kA/m (272 Oe) for Co 10 Cr 90, it is related to the grain size and the structural change. Besides, the magnetic anisotropy constant was determined for each composition. Magnetic thermogravimetric analysis allowed to obtain Curie temperatures corresponding to the formation of hcp-Co(Cr) and fcc-Co(Cr) solid solutions. - Highlights: • Mechanical alloying (MA) induces the formation of solid solutions of Co–Cr system in non-equilibrium. • We report the crystal structure and the magnetic behavior of Co–Cr alloys produced by MA. • MA improves the magnetic properties of Co–Cr system

Synthesis of (U,Zr)C solid solutions under exothermic conditions

International Nuclear Information System (INIS)

Wang, L.L.; Moore, H.G.; Gladson, J.W.

1993-01-01

The reactions of forming (U,Zr)C solid solutions from their elemental components or similarly less stable reactants such as UC 2 are strongly exothermic due to the high stability of these solid solutions. A simple approach of utilizing this heat of formation energy to assist the solid solution reaction process is to intimately mix the less stable reactant powders and then pressed them into a compact. The compact is then heated to the ignition temperature of the reaction. The feasibility of this reaction method to synthesize (U,Zr)C solid solutions has been demonstrated in this study. The preliminary results also show that both the initial composition and the heating rate have a significant effect on the nature of the reaction process. As expected the degree of powder mixing was also found to affect the completeness of the reaction

Activity coefficients at infinite dilution of organic solutes in 1-hexyl-3-methylimidazolium trifluoroacetate and influence of interfacial adsorption using gas–liquid chromatography

International Nuclear Information System (INIS)

Jiang, Lin-Kun; Wang, Li-Sheng; Du, Chao-Jun; Wang, Xue-Yuan

2014-01-01

Highlights: • Activity coefficients at infinite dilution of organic solutes in [HMIM][TFA] were determined. • The contribution of interfacial adsorption to the retention mechanism was estimated. • The partial molar excess enthalpies and the solubility parameters of [HMIM][TFA] were calculated. -- Abstract: Activity coefficients at infinite dilution for a series of organic solutes in the ionic liquid 1-hexyl-3-methylimidazolium trifluoroacetate ([HMIM][TFA]) have been determined by gas–liquid chromatography at the temperature range from (303.15 to 363.15) K. The contribution of interfacial adsorption to the retention mechanism was estimated by changing the loading of ionic liquid in stationary phase. The partial molar excess enthalpies at infinite dilution and the solubility parameters of ionic liquid were also calculated from the experimental values of activity coefficients at infinite dilution

Activity coefficients at infinite dilution measurements for organic solutes and water in the ionic liquid 1-ethyl-3-methylimidazolium tetracyanoborate

International Nuclear Information System (INIS)

Domanska, Urszula; Krolikowska, Marta; Acree, William E.; Baker, Gary A.

2011-01-01

Research highlights: → Measurements of activity coefficients at infinite dilution using GLC. → 36 organic solvents and water in the ionic liquid 1-ethyl-3-methylimidazolium tetracyanoborate, [EMIM][TCB]. → Possible entrainer for different separation processes. → The partial molar excess thermodynamic functions at infinite dilution were calculated. - Abstract: The activity coefficients at infinite dilution, γ 13 ∞ , for 36 solutes, including alkanes, cycloalkanes, alkenes, alkynes, aromatic hydrocarbons, alcohols, thiophene, tetrahydrofuran, ethers, acetone, and water, in the ionic liquid 1-ethyl-3-methylimidazolium tetracyanoborate, [EMIM][TCB], were determined by gas-liquid chromatography at temperatures from 298.15 K to 358.15 K. These values are compared to those previously published for selected solutes in the same ionic liquid. The values of the partial molar excess Gibbs free energy ΔG 1 E,∞ , enthalpy ΔH 1 E,∞ , and entropy ΔS 1 E,∞ at infinite dilution were calculated from the experimental γ 13 ∞ values obtained over the temperature range. Three gas-liquid partition coefficients, K L were calculated for all solutes and the Abraham solvation parameter model is discussed. The values of the selectivity for different separation problems were calculated from γ 13 ∞ and compared to literature values for N-methyl-2-pyrrolidinone (NMP), sulfolane, 1-decyl-3-methylimidazolium tetracyanoborate, [DMIM][TCB], and additional ionic liquids.

Study of vibrational and magnetic excitations in Ni sub c Mg sub 1 sub - sub c O solid solutions by Raman spectroscopy

CERN Document Server

Cazzanelli, E; Mariotto, G; Mironova-Ulmane, N

2003-01-01

The Raman scattering by phonons and magnons was studied for the first time in the polycrystalline solid solutions Ni sub c Mg sub 1 sub - sub c O. The experimental Raman spectrum for c = 0.9 is similar to that of NiO and consists of six well resolved bands, whose origins are the disorder-induced one-phonon scattering (bands at 400 and 500 cm sup - sup 1), two-phonon scattering (bands at 750, 900, and 1100 cm sup - sup 1), and two-magnon scattering (the broad band at approx 1400 cm sup - sup 1). We found that the dependence of the two-magnon band in solid solutions on the composition and temperature is consistent with their magnetic phase diagram. We also observed that the relative contribution of two-phonon scattering decreases strongly upon dilution with magnesium ions and disappears completely at c < 0.5. Such behaviour is explained in terms of a disorder-induced effect, which increases the probability of the one-phonon scattering processes.

The calcium oxide influence on formation of manganese, calcium pyrovanadate solid solutions

International Nuclear Information System (INIS)

Vatolin, N.A.; Volkova, P.I.; Sapozhnikova, T.V.; Ovchinnikova, L.A.

1988-01-01

The X-ray graphic, derivatographic, microscopic and chemical methods are used to study solid solutions of manganese, calcium pyrovanadates containing 1-10 mass% CaO and the products of interaction of reprocessing charges of vanadium-containing converter slags intended for he formation of manganese and calcium pyrovanadates with additions of calcium oxide within 10-90 mass%. It is established that in the case of 1-6 mass% CaO content in manganese pyrovanadate solid interstitial solutions appear, while at 6-20 mass% CaO - solid substitution solutions form. The results of calculating elementary cell parameters as well as melting temperatures and pyrovanadate solid solution solubility depending on CaO content are presented. The best solubility of introduction solid solutions during vanadium extraction according to the lime technology is found

X-Ray Characterization of Non-Equilibrium Solid Solutions

International Nuclear Information System (INIS)

Brown, A.; Rosdahl, Oe.

1975-01-01

The Rudman approach to composition line broadening in X-ray diffraction patterns, originally designed for the study of diffusion in alloys, is seen to provide a basis for characterizing inhomogeneous solid solutions. Limitations, imposed on this treatment when the cell dimensions of the primary components differ by less than 0.1 A, are attributable to experimental effects such as instrument broadening. These limitations can be overcome by a rigorous numerical treatment of the measured data. Thus, separate elimination of the Kα 2 radiation component followed by iterative deconvolution are advocated for the recovery of the intrinsic broadening. This course of action is made possible chiefly through the availability of large, fast memory computers and primary data recorded in the form of a step scan on punched paper tape. The characteristics of inhomogeneous solid solutions made available by the above treatment are the identity of closely similar, solid solution phases, the frequency distribution curve for a chosen component, and the degree of homogeneity of the X-ray sample

Quantitation of (R)- and (S)-linalool in beer using solid phase microextraction (SPME) in combination with a stable isotope dilution assay (SIDA).

Science.gov (United States)

Steinhaus, Martin; Fritsch, Helge T; Schieberle, Peter

2003-11-19

A stable isotope dilution assay (SIDA) was developed for the quantitation of both linalool enantiomers using synthesized [2H(2)]R/S-linalool as the internal standard. For enrichment of the target compound from beer, a solid phase microextraction method (SPME) was developed. In comparison to the more time-consuming extraction/distillation cleanup of the beer samples, the results obtained by SPME/SIDA were very similar, even under nonequilibration conditions. Analysis of five different types of beer showed significant differences in the linalool concentrations, which were clearly correlated with the intensity of the hoppy aroma note as evaluated by a sensory panel. In addition, significant differences in the R/S ratios were measured in the beers. The SPME/SIDA yielded exact data independently from headspace sampling parameters, such as exposure time or ionic strength of the solution.

First-principles calculations of the structural and thermodynamic properties of bcc, fcc and hcp solid solutions in the Al-TM (TM = Ti, Zr and Hf) systems: A comparison of cluster expansion and supercell methods

International Nuclear Information System (INIS)

Ghosh, G.; Walle, A. van de; Asta, M.

2008-01-01

The thermodynamic properties of solid solutions with body-centered cubic (bcc), face-centered cubic (fcc) and hexagonal close-packed (hcp) structures in the Al-TM (TM = Ti, Zr and Hf) systems are calculated from first-principles using cluster expansion (CE), Monte-Carlo simulation and supercell methods. The 32-atom special quasirandom structure (SQS) supercells are employed to compute properties at 25, 50 and 75 at.% TM compositions, and 64-atom supercells have been employed to compute properties of alloys in the dilute concentration limit (one solute and 63 solvent atoms). In general, the energy of mixing (Δ m E) calculated by CE and dilute supercells agree very well. In the concentrated region, the Δ m E values calculated by CE and SQS methods also agree well in many cases; however, noteworthy discrepancies are found in some cases, which we argue originate from inherent elastic and dynamic instabilities of the relevant parent lattice structures. The importance of short-range order on the calculated values of Δ m E for hcp Al-Ti alloys is demonstrated. We also present calculated results for the composition dependence of the atomic volumes in random solid solutions with bcc, fcc and hcp structures. The properties of solid solutions reported here may be integrated within the CALPHAD formalism to develop reliable thermodynamic databases in order to facilitate: (i) calculations of stable and metastable phase diagrams of binary and multicomponent systems, (ii) alloy design, and (iii) processing of Al-TM-based alloys

Comparative solution and solid-phase glycosylations toward a disaccharide library

DEFF Research Database (Denmark)

Agoston, K.; Kröger, Lars; Agoston, Agnes

2009-01-01

A comparative study on solution-phase and solid-phase oligosaccharide synthesis was performed. A 16-member library containing all regioisomers of Glc-Glc, Glc-Gal, Gal-Glc, and Gal-Gal disaccharides was synthesized both in solution and on solid phase. The various reaction conditions for different...

Conductivity and thermopower studies of bis-tetramethyltetraselenafulvalenium hexafluorophosphide, bis-tetramethyltetrathiafulvalenium hexafluorophosphide, and their solid solutions, (TMTSF1-xTMTTFx)2PF6

DEFF Research Database (Denmark)

Mortensen, Kell; Engler, E. M.

1984-01-01

The conductivity σ and the thermoelectric power S have been studied experimentally on the organic conductors bis-tetramethyltetraselenafulvalenium hexafluorophosphide [(TMTSF)2PF6] and bis-tetramethyltetrathiafulvalenium hexafluorophosphide [(TMTTF)2PF6] and their solid solutions: (TMTSF1-xTMTTFx)2......PF6. Dramatic effects are seen in σ already when dilute concentrations of TMTTF molecules are introduced in the TMTSF chains, and for x=0.1, σ shows generally activated behavior. The thermopower, on the contrary, remains basically unaffected for x at least as large as 0.25. These unusual findings...

On calculation of lattice parameters of refractory metal solid solutions

International Nuclear Information System (INIS)

Barsukov, A.D.; Zhuravleva, A.D.; Pedos, A.A.

1995-01-01

Technique for calculating lattice periods of solid solutions is suggested. Experimental and calculation values of lattice periods of some solid solutions on the basis of refractory metals (V-Cr, Nb-Zr, Mo-W and other) are presented. Calculation error was correlated with experimental one. 7 refs.; 2 tabs

Evaluation of a cell-biopolymer sorbent for uptake of strontium from dilute solutions

International Nuclear Information System (INIS)

Watson, J.S.; Scott, C.D.; Faison, B.D.

1990-01-01

Immobilization of Micrococcus luteus within beads of bone gelatin results in a material which is able to adsorb significant quantities of strontium from dilute aqueous solutions analogous to some nuclear industry wastewaters. The mechanism appears to be principally an ion-exchange phenomenon. Both the bone gelatin and the microbial cells contribute to strontium removal; the principal contribution from the cells appears to be sorption onto cell wall material. This particular biosorbent may not be an immediate replacement for conventional ion-exchange materials currently used to remove strontium from wastewaters. However, the study does indicate that relatively inexpensive biological materials can be incorporated into particulate forms such as gel beads and used for the removal of dissolved metal ions from aqueous solution

Non‐diluted seawater enhances nasal ciliary beat frequency and wound repair speed compared to diluted seawater and normal saline

Science.gov (United States)

Bonnomet, Arnaud; Luczka, Emilie; Coraux, Christelle

2016-01-01

Background The regulation of mucociliary clearance is a key part of the defense mechanisms developed by the airway epithelium. If a high aggregate quality of evidence shows the clinical effectiveness of nasal irrigation, there is a lack of studies showing the intrinsic role of the different irrigation solutions allowing such results. This study investigated the impact of solutions with different pH and ionic compositions, eg, normal saline, non‐diluted seawater and diluted seawater, on nasal mucosa functional parameters. Methods For this randomized, controlled, blinded, in vitro study, we used airway epithelial cells obtained from 13 nasal polyps explants to measure ciliary beat frequency (CBF) and epithelial wound repair speed (WRS) in response to 3 isotonic nasal irrigation solutions: (1) normal saline 0.9%; (2) non‐diluted seawater (Physiomer®); and (3) 30% diluted seawater (Stérimar). The results were compared to control (cell culture medium). Results Non‐diluted seawater enhanced the CBF and the WRS when compared to diluted seawater and to normal saline. When compared to the control, it significantly enhanced CBF and slightly, though nonsignificantly, improved the WRS. Interestingly, normal saline markedly reduced the number of epithelial cells and ciliated cells when compared to the control condition. Conclusion Our results suggest that the physicochemical features of the nasal wash solution is important because it determines the optimal conditions to enhance CBF and epithelial WRS thus preserving the respiratory mucosa in pathological conditions. Non‐diluted seawater obtains the best results on CBF and WRS vs normal saline showing a deleterious effect on epithelial cell function. PMID:27101776

Precipitation of Nd-Ca carbonate solid solution at 25 degrees C

International Nuclear Information System (INIS)

Carroll, S.A.

1993-01-01

The formation of a Nd-Ca carbonate solid solution was studied by monitoring the reactions of calcite with aqueous Nd, orthorhombic NdOHCO 3 (s) with aqueous Ca, and calcite with hexagonal Nd-carbonate solid phase as a function of time at 25 degrees C and controlled pCO 2 (g). All experiments reached steady state after 200 h of reaction. The dominant mechanism controlling the formation of the solid solution was precipitation of a Nd-Ca carbonate phase from the bulk solution as individual crystals or at the orthorhombic NdOHCO 3 (s)-solution interface. The lack of Nd adsorption or solid solution at the calcite-solution interface suggests that the solid solution was orthorhombic and may be modeled as a mixture of orthorhombic NdOHCO 3 (s) and aragonite. Orthorhombic NdOHCO 3 (s) was determined to be the stable Nd-carbonate phase in the Nd-CO 2 -H 2 O system at pCO 2 (g) 0.1 atmospheres at 25 degrees C. The equilibrium constant corrected to zero ionic strength for orthorhombic NdOHCO 3 (s) solubility is 10 10.41(±0.29) for the following: NdOHCO 3 (s) + 3H + = Nd 3+ + CO 2 (g) + H 2 O. Results are discussed in relation to radioactive waste disposal by burial, and specifically in relation to americium chemistry

Features of solid solutions composition in magnesium with yttrium alloys

International Nuclear Information System (INIS)

Drits, M.E.; Rokhlin, L.L.; Tarytina, I.E.

1983-01-01

Additional data on features of yttrium solid solutions composition in magnesium in the course of their decomposition investigation in the case of aging are obtianed. The investigation has been carried out on the base of a binary magnesium-yttrium alloy the composition of which has been close to maximum solubility (at eutectic temperature) and magnesium-yttrium alloys additionally doped with zinc. It is shown that higher yttrium solubility in solid magnesium than it has been expected, issueing from the difference in atomic radii of these metals indicates electron yttrium-magnesium atoms interaction. In oversaturated magnesium-yttrium solid solutions at earlier decomposition stages Mg 3 Cd type ordering is observed. At aging temperatures up to 250 deg C and long exposures corresponding to highest strengthening in oversaturated magnesium yttrium solid solutions a rhombic crystal lattice phase with three symmetric orientations is formed

Effect of 60Co gamma-ray irradiation on dilute aqueous solutions of surfactants

International Nuclear Information System (INIS)

Sawai, Teruko; Shimokawa, Toshinari; Miki, Yasushi; Oseko, Koichi; Sawai, Takeshi

1978-01-01

Present work deals with the effects of gamma irradiation from 60 Co γ-ray source upon aqueous solutions of three kinds of surfactants. When dilute aqueous solutions of sodium dodecyl sulfate (SDS, anionic), cethyl trimethyl ammonium chloride (CTAC, cationic), and polyoxyethylene lauryl ether (POE, non-ionic) were irradiated with γ-rays at a room temperature, the residual concentration, products, surface tension, and forming power were examined by colorimetric method, IR spectrophotometric method, gaschromatography, Ross-Miles method, and Traube's stalagmometer etc. These surfactants were decomposed by the irradiation and thus the surface tension increased and the forming power, on the contrary, decreased with dose. Radiation chemical yields (G-value) of the degradation were about 1 for the solutions of SDS and CTAC, and about 0.3 for the POE solution. From the experimental results, it was found that following chemical reactions seem to occur followed by the radiolysis of water: a) bond cleavage of ester for SDS, of CN for CTAC, and of oxyethylene for POE, b) hydrogen abstraction from the surfactants, c) production of CO bond in the presence of dissolved oxygen. (auth.)

Theory of the high-frequency limiting viscosity of a dilute polymer solution. Pt. 2

Energy Technology Data Exchange (ETDEWEB)

Doi, M; Nakajima, H; Wada, Y

1976-06-01

High-frequency limiting viscosities of dilute polymer solutions are calculated on the basis of the author's previous theory for (1) necklace model of a chain with constant bond length and bond angle under a hindering rotational potential, and (2) broken rod model consisting of N rods with equal length connected by universal joints. Exact treatment is possible for a once-broken rod model, but the Monte Carlo method is used in the other calculations.

Precipitation in Al–Mg solid solution prepared by solidification under high pressure

International Nuclear Information System (INIS)

Jie, J.C.; Wang, H.W.; Zou, C.M.; Wei, Z.J.; Li, T.J.

2014-01-01

The precipitation in Al–Mg solid solution containing 21.6 at.% Mg prepared by solidification under 2 GPa was investigated. The results show that the γ-Al 12 Mg 17 phase is formed and the β′ phase cannot be observed in the solid solution during ageing process. The precipitation of γ and β phases takes place in a non-uniform manner during heating process, i.e. the γ and β phases are first formed in the interdendritic region, which is caused by the inhomogeneous distribution of Mg atoms in the solid solution solidified under high pressure. Peak splitting of X-ray diffraction patterns of Al(Mg) solid solution appears, and then disappears when the samples are aged at 423 K for different times, due to the non-uniform precipitation in Al–Mg solid solution. The direct transformation from the γ to β phase is observed after ageing at 423 K for 24 h. It is considered that the β phase is formed through a peritectoid reaction of α + γ → β which needs the diffusion of Mg atoms across the interface of α/γ phases. - Highlights: • The γ phase is formed and the β′ phase is be observed in Al(Mg) solid solution. • Peak splitting of XRD pattern of Al(Mg) solid solution appears during aged at 150 °C. • The β phase is formed through a peritectoid reaction of α + γ → β

X-Ray Characterization of Non-Equilibrium Solid Solutions

Energy Technology Data Exchange (ETDEWEB)

Brown, A; Rosdahl, Oe

1975-07-01

The Rudman approach to composition line broadening in X-ray diffraction patterns, originally designed for the study of diffusion in alloys, is seen to provide a basis for characterizing inhomogeneous solid solutions. Limitations, imposed on this treatment when the cell dimensions of the primary components differ by less than 0.1 A, are attributable to experimental effects such as instrument broadening. These limitations can be overcome by a rigorous numerical treatment of the measured data. Thus, separate elimination of the Kalpha{sub 2} radiation component followed by iterative deconvolution are advocated for the recovery of the intrinsic broadening. This course of action is made possible chiefly through the availability of large, fast memory computers and primary data recorded in the form of a step scan on punched paper tape. The characteristics of inhomogeneous solid solutions made available by the above treatment are the identity of closely similar, solid solution phases, the frequency distribution curve for a chosen component, and the degree of homogeneity of the X-ray sample

Centrifugal extractor for liquid-liquid extraction with solid particles in suspension and installation using several extractors

International Nuclear Information System (INIS)

Bathellier, A.; Germain, M.; Lamotte, C.; Pasquiou, J.Y.

1986-01-01

The design claimed avoid clogging the extractor by solids which are collected in a conical decantation chamber. Application is made to the separation of the aqueous nitric solution, the organic phase of TBP diluted by an aliphatic hydrocarbon and heavy solid particles during spent fuel reprocessing [fr

Thermodynamics of dilute 3He-4He solid solutions with hcp structure

Science.gov (United States)

Chishko, K. A.

2018-02-01

To interpret the anomalies in heat capacity CV(T) and temperature-dependent pressure P(T) of solid hexagonal close-packed (hcp) 4He we exploit the model of hcp crystalline polytype with specific lattice degrees of freedom and describe the thermodynamics of impurity-free 4He solid as superposition of phononic and polytypic contributions. The hcp-based polytype is a stack of 2D basal atomic monolayers on triangular lattice packed with arbitrary long (up to infinity) spatial period along the hexagonal c axis perpendicular to the basal planes. It is a crystal with perfect ordering along the layers, but without microscopic translational symmetry in perpendicular direction (which remains, nevertheless, the rotational crystallographic axis of third order, so that the polytype can be considered as semidisordered system). Each atom of the hcp polytype has twelve crystallographic neighbors in both first and second coordination spheres at any arbitrary packing order. It is shown that the crystal of such structure behaves as anisotropic elastic medium with specific dispersion law of phonon excitations along c axis. The free energy and the heat capacity consist of two terms: one of them is a normal contribution [with CV(T) ˜ T3] from phonon excitations in an anisotropic lattice of hexagonal symmetry, and another term (an "excessive" heat) is a contribution resulted by packing entropy from quasi-one-dimensional system of 2D basal planes on triangular lattice stacked randomly along c axis without braking the closest pack between neighboring atomic layers. The excessive part of the free energy has been treated within 1D quasi-Ising (lattice gas) model using the transfer matrix approach. This model makes us possible to interpret successfully the thermodynamic anomaly (heat capacity peak in hcp 4He) observed experimentally.

Thermodynamics of oxygen in solid solution in vanadium and niobium--vanadium alloys

International Nuclear Information System (INIS)

Steckel, G.L.

1977-01-01

A thermodynamic study was made of the vanadium-oxygen and niobium-vanadium-oxygen systems utilizing the solid state galvanic cell technique. Investigations were made with a ThO 2 /Y 2 O 3 electrolyte over the temperature ranges 700 to 1200 0 C (973 to 1473 K) for the binary system and 650 to 1150 0 C (923 to 1423 K) for the ternary system. The activity of oxygen in vanadium obeys Henry's law for the temperatures of this investigation for concentrations up to 3.2 at. percent oxygen. For higher concentrations the activity coefficient shows positive deviations from Henry's law. The terminal solubility of oxygen in vanadium was determined. The activity of oxygen in Nb--V alloys obeys Henry's law for the temperatures of this study for oxygen concentrations less than approximately 2 at. percent. For certain Nb/V ratios Henry's law is obeyed for concentrations as high as 6.5 at. percent oxygen. First order entropy and enthalpy interaction coefficients have been determined to describe the effect on the oxygen activity of niobium additions to vanadium-rich alloys with dilute oxygen concentrations. Niobium causes relatively small decreases in the oxygen activity of V-rich alloys and increases the oxygen solubility limit. Vanadium additions to Nb-rich alloys also increases the oxygen solubility and causes substantial decreases in the dilute solution oxygen activities. The change in the thermodynamic properties when molecular oxygen dissolves in vanadium and niobium--vanadium alloys and the equilibrium oxygen pressure over the binary and ternary systems were also determined

Non-diluted seawater enhances nasal ciliary beat frequency and wound repair speed compared to diluted seawater and normal saline.

Science.gov (United States)

Bonnomet, Arnaud; Luczka, Emilie; Coraux, Christelle; de Gabory, Ludovic

2016-10-01

The regulation of mucociliary clearance is a key part of the defense mechanisms developed by the airway epithelium. If a high aggregate quality of evidence shows the clinical effectiveness of nasal irrigation, there is a lack of studies showing the intrinsic role of the different irrigation solutions allowing such results. This study investigated the impact of solutions with different pH and ionic compositions, eg, normal saline, non-diluted seawater and diluted seawater, on nasal mucosa functional parameters. For this randomized, controlled, blinded, in vitro study, we used airway epithelial cells obtained from 13 nasal polyps explants to measure ciliary beat frequency (CBF) and epithelial wound repair speed (WRS) in response to 3 isotonic nasal irrigation solutions: (1) normal saline 0.9%; (2) non-diluted seawater (Physiomer®); and (3) 30% diluted seawater (Stérimar). The results were compared to control (cell culture medium). Non-diluted seawater enhanced the CBF and the WRS when compared to diluted seawater and to normal saline. When compared to the control, it significantly enhanced CBF and slightly, though nonsignificantly, improved the WRS. Interestingly, normal saline markedly reduced the number of epithelial cells and ciliated cells when compared to the control condition. Our results suggest that the physicochemical features of the nasal wash solution is important because it determines the optimal conditions to enhance CBF and epithelial WRS thus preserving the respiratory mucosa in pathological conditions. Non-diluted seawater obtains the best results on CBF and WRS vs normal saline showing a deleterious effect on epithelial cell function. © 2016 The Authors International Forum of Allergy & Rhinology, published by ARSAAOA, LLC.

Plutonium determination by isotope dilution

International Nuclear Information System (INIS)

Lucas, M.

1980-01-01

The principle is to add to a known amount of the analysed solution a known amount of a spike solution consisting of plutonium 242. The isotopic composition of the resulting mixture is then determined by surface ionization mass spectrometry, and the plutonium concentration in the solution is deduced, from this measurement. For irradiated fuels neutronic studies or for fissile materials balance measurements, requiring the knowledge of the ratio U/Pu or of concentration both uranium and plutonium, it is better to use the double spike isotope dilution method, with a spike solution of known 233 U- 242 Pu ratio. Using this method, the ratio of uranium to plutonium concentration in the irradiated fuel solution can be determined without any accurate measurement of the mixed amounts of sample and spike solutions. For fissile material balance measurements, the uranium concentration is determined by using single isotope dilution, and the plutonium concentration is deduced from the ratio Pu/U and U concentration. The main advantages of isotope dilution are its selectivity, accuracy and very high sensitivity. The recent improvements made to surface ionization mass spectrometers have considerably increased the precision of the measurements; a relative precision of about 0.2% to 0.3% is obtained currently, but it could be reduced to 0.1%, in the future, with a careful control of the experimental procedures. The detection limite is around 0.1 ppb [fr

Modelling solid solutions with cluster expansion, special quasirandom structures, and thermodynamic approaches

Science.gov (United States)

Saltas, V.; Horlait, D.; Sgourou, E. N.; Vallianatos, F.; Chroneos, A.

2017-12-01

Modelling solid solutions is fundamental in understanding the properties of numerous materials which are important for a range of applications in various fields including nanoelectronics and energy materials such as fuel cells, nuclear materials, and batteries, as the systematic understanding throughout the composition range of solid solutions for a range of conditions can be challenging from an experimental viewpoint. The main motivation of this review is to contribute to the discussion in the community of the applicability of methods that constitute the investigation of solid solutions computationally tractable. This is important as computational modelling is required to calculate numerous defect properties and to act synergistically with experiment to understand these materials. This review will examine in detail two examples: silicon germanium alloys and MAX phase solid solutions. Silicon germanium alloys are technologically important in nanoelectronic devices and are also relevant considering the recent advances in ternary and quaternary groups IV and III-V semiconductor alloys. MAX phase solid solutions display a palette of ceramic and metallic properties and it is anticipated that via their tuning they can have applications ranging from nuclear to aerospace industries as well as being precursors for particular MXenes. In the final part, a brief summary assesses the limitations and possibilities of the methodologies discussed, whereas there is discussion on the future directions and examples of solid solution systems that should prove fruitful to consider.

Temperature dependence of the mechanical properties of equiatomic solid solution alloys with face-centered cubic crystal structures

International Nuclear Information System (INIS)

Wu, Z.; Bei, H.; Pharr, G.M.; George, E.P.

2014-01-01

Compared to decades-old theories of strengthening in dilute solid solutions, the mechanical behavior of concentrated solid solutions is relatively poorly understood. A special subset of these materials includes alloys in which the constituent elements are present in equal atomic proportions, including the high-entropy alloys of recent interest. A unique characteristic of equiatomic alloys is the absence of “solvent” and “solute” atoms, resulting in a breakdown of the textbook picture of dislocations moving through a solvent lattice and encountering discrete solute obstacles. To clarify the mechanical behavior of this interesting new class of materials, we investigate here a family of equiatomic binary, ternary and quaternary alloys based on the elements Fe, Ni, Co, Cr and Mn that were previously shown to be single-phase face-centered cubic (fcc) solid solutions. The alloys were arc-melted, drop-cast, homogenized, cold-rolled and recrystallized to produce equiaxed microstructures with comparable grain sizes. Tensile tests were performed at an engineering strain rate of 10 −3 s −1 at temperatures in the range 77–673 K. Unalloyed fcc Ni was processed similarly and tested for comparison. The flow stresses depend to varying degrees on temperature, with some (e.g. NiCoCr, NiCoCrMn and FeNiCoCr) exhibiting yield and ultimate strengths that increase strongly with decreasing temperature, while others (e.g. NiCo and Ni) exhibit very weak temperature dependencies. To better understand this behavior, the temperature dependencies of the yield strength and strain hardening were analyzed separately. Lattice friction appears to be the predominant component of the temperature-dependent yield stress, possibly because the Peierls barrier height decreases with increasing temperature due to a thermally induced increase of dislocation width. In the early stages of plastic flow (5–13% strain, depending on material), the temperature dependence of strain hardening is due

State of atoms and interatomic interactions in complex perovskite-like oxides. Communication XVIII. Magnetic dilution in the LaCrO3-LaGaO3 system

International Nuclear Information System (INIS)

Chezhina, N.V.; Zolotukhina, N.V.; Bodritskaya, Eh.V.

2005-01-01

Solid solutions LaCr x Ga 1-x O 3 (0.01 ≤ x ≤ 0.10) were synthesized using the ceramic technique and characterized by X-ray powder diffraction and chemical analysis. Magnetic susceptibility of dilute solid solutions of lanthanum chromate in lanthanum gallate was studied in the temperature range 77-400 K. The calculated antiferromagnetic exchange parameter and distribution of chromium atoms over the diamagnetic matrix gave evidence for enhanced chromium aggregation and weakened magnetic exchange in lanthanum gallate compared to lanthanum aluminate [ru

Dilute solution properties of canary seed (Phalaris canariensis) starch in comparison to wheat starch.

Science.gov (United States)

Irani, Mahdi; Razavi, Seyed M A; Abdel-Aal, El-Sayed M; Hucl, Pierre; Patterson, Carol Ann

2016-06-01

Dilute solution properties of an unknown starch are important to understand its performance and applications in food and non-food industries. In this paper, rheological and molecular properties (intrinsic viscosity, molecular weight, shape factor, voluminosity, conformation and coil overlap parameters) of the starches from two hairless canary seed varieties (CO5041 & CDC Maria) developed for food use were evaluated in the dilute regime (Starch dispersions in DMSO (0.5g/dl)) and compared with wheat starch (WS). The results showed that Higiro model is the best among five applied models for intrinsic viscosity determination of canary seed starch (CSS) and WS on the basis of coefficient of determination (R(2)) and root mean square error (RMSE). WS sample showed higher intrinsic viscosity value (1.670dl/g) in comparison to CSS samples (1.325-1.397dl/g). Berry number and the slope of master curve demonstrated that CSS and WS samples were in dilute domain without entanglement occurrence. The shape factor suggested spherical and ellipsoidal structure for CO5041 starch and ellipsoidal for CDC Maria starch and WS. The molecular weight, coil radius and coil volume of CSSs were smaller than WS. The behavior and molecular characterization of canary seed starch showed its unique properties compared with wheat starch. Copyright © 2016 Elsevier B.V. All rights reserved.

Turbulent solutal convection and surface patterning in solid dissolution

International Nuclear Information System (INIS)

Sullivan, T.S.; Liu, Y.; Ecke, R.E.

1996-01-01

We describe experiments in which crystals of NaCl, KBr, and KCl are dissolved from below by aqueous solutions containing concentrations of the respective salts from zero concentration to near saturation. The solution near the solid-liquid interface is gravitationally unstable, producing turbulent hydrodynamic motion similar to thermal convection from a single surface cooled from above. The coupling of the fluid flow with the solid dissolution produces irregular patterns at the solid-liquid interface with a distribution of horizontal length scales. The dissolution mass flux and the pattern length scales are compared with a turbulent boundary layer model. Remarkable agreement is found, showing that the fluid motion controls both the dissolution rate and the interface patterning. copyright 1996 The American Physical Society

Magnetic susceptibilities of Ca/sub y/U/sub 1-y/O/sub 2+x/ solid solutions

International Nuclear Information System (INIS)

Hinatsu, Y.; Fujino, T.

1988-01-01

Magnetic susceptibilities of Ca/sub y/U/sub 1-y/O/sub 2+x/ solid solutions with fluorite structure were measured from 4.2 K to room temperature. An antiferromagnetic transition was observed for all the solid solutions examined in this study (y ≤ 0.33). The Neel temperature of the oxygen-hypostoichiometric solid solutions (x 2 solid solutions, but different from that of (U,Th)O 2 solid solutions. The effective magnetic moment decreased with increasing calcium concentration, which indicates the oxidation of uranium in the solid solutions. From the analysis of the magnetic susceptibility data, it was found that the oxidation state of uranium was either tetravalent or pentavalent. The Neel temperature of the hyperstoichiometric solid solutions (x > 0) did not change appreciably with calcium concentrations. From the comparison of the magnetic susceptibility data of the hypostoichiometric solid solutions with those of the hyperstoichiometric solid solutions, the effect of oxygen vacancies is more significant than that of interstitial oxygens on the decrease of magnetic interactions between uranium ions

Study on radiation-induced deactivation and post-deactivation of some oxide-reductase in dilute aqueous solutions and protective effects: Pt. 2

International Nuclear Information System (INIS)

Ha Hongfei; Chen Yiqing

1993-01-01

The post-deactivation of irradiated catalase in dilute aqueous solution was found and investigated. Post-deactivation of irradiated catalase means that the catalase in dilute aqueous solution could not only be deactivated during γ-irradiation, but it has also been deactivated continuously for some time after the irradiated samples were taken out of the radiation field. No reports about this phenomenon in literature were searched up to now. The effects of absorbed dose, initial catalase concentration in solutions, atmosphere, temperature and additive on post-deactivation of catalase were investigated. H 2 O 2 produced by water radiolysis may attend the post-deactivation reaction in some way. Oxygen in enzyme samples in necessitous for the post-deactivation. 1 x 10 -4 to 5 x 10 -3 mol/L of CH 3 CH 2 OH, HCOONa and EDTA could control the post-deactivation efficiently

Thermal expansion studies on uranium-neodymium mixed oxide solid solutions

International Nuclear Information System (INIS)

Panneerselvam, G.; Venkata Krishnan, R.; Antony, M.P.; Nagarajan, K.

2012-01-01

Uranium-Neodymium mixed oxides solid solutions (U 1-y Nd y ) O 2 (y=0.2-0.95) were prepared by combustion synthesis using citric acid as fuel. Structural characterization and computation of lattice parameter was carried out from room temperature X-ray diffraction measurements. Single-phase fluorite structure was observed up to y=0.80. For solid solutions with y>0.80 additional Nd 2 O 3 lines were visible

Reaction paths and equilibrium end-points in solid-solution aqueous-solution systems

Science.gov (United States)

Glynn, P.D.; Reardon, E.J.; Plummer, Niel; Busenberg, E.

1990-01-01

Equations are presented describing equilibrium in binary solid-solution aqueous-solution (SSAS) systems after a dissolution, precipitation, or recrystallization process, as a function of the composition and relative proportion of the initial phases. Equilibrium phase diagrams incorporating the concept of stoichiometric saturation are used to interpret possible reaction paths and to demonstrate relations between stoichiometric saturation, primary saturation, and thermodynamic equilibrium states. The concept of stoichiometric saturation is found useful in interpreting and putting limits on dissolution pathways, but there currently is no basis for possible application of this concept to the prediction and/ or understanding of precipitation processes. Previously published dissolution experiments for (Ba, Sr)SO4 and (Sr, Ca)C??O3orth. solids are interpreted using equilibrium phase diagrams. These studies show that stoichiometric saturation can control, or at least influence, initial congruent dissolution pathways. The results for (Sr, Ca)CO3orth. solids reveal that stoichiometric saturation can also control the initial stages of incongruent dissolution, despite the intrinsic instability of some of the initial solids. In contrast, recrystallisation experiments in the highly soluble KCl-KBr-H2O system demonstrate equilibrium. The excess free energy of mixing calculated for K(Cl, Br) solids is closely modeled by the relation GE = ??KBr??KClRT[a0 + a1(2??KBr-1)], where a0 is 1.40 ?? 0.02, a1, is -0.08 ?? 0.03 at 25??C, and ??KBr and ??KCl are the mole fractions of KBr and KCl in the solids. The phase diagram constructed using this fit reveals an alyotropic maximum located at ??KBr = 0.676 and at a total solubility product, ???? = [K+]([Cl-] + [Br-]) = 15.35. ?? 1990.

The cathodic reduction of dioxygen on uranium oxide in dilute alkaline aqueous solution

International Nuclear Information System (INIS)

Hocking, W.H.; Betteridge, J.S.; Shoesmith, D.W.

1991-09-01

The cathodic reduction of dioxygen on uranium oxide in dilute alkaline aqueous solutions has been investigated within the context of a program to develop a comprehensive model to predict the behaviour of used CANDU (Canada Deuterium Uranium) nuclear fuel under disposal-vault conditions. Two different kinds of ceramic UO 2 were studied: reactor-grade CANDU fuel with normal p-type electrical conductivity and low-resistance material that exhibits n-type photoelectrochemical behaviour. The transport of electroactive species in solution was controlled by varying the rotation rate of rotating disc electrodes (RDE) and rotating ring-disc electrodes (RRDE). Steady-state polarization measurements were made using the current-interrupt method to compensate for the potential drop caused by ohmic resistance. Any release of peroxide to solution from the UO 2 (disc) surface could be monitored by oxidizing it at the Au ring of an RRDE. The existing theory for the cathodic 0 2 -reduction process as applied to RDE and RRDE experiments has been reviewed as a starting point for the interpretation of the results obtained in our work. (37 figs., 2 tabs., 170 refs.)

Thermodynamic characteristics of systems with solid solutions composed of crystal hydrates of lanthanide and yttrium chlorides, at 250C. III. Systems of Roozeboom's type IV, with restricted solid solutions

International Nuclear Information System (INIS)

Sokolova, N.P.

1983-01-01

The values of the activity, the activity coefficients, the free energy of mixing and the excess free energy of mixing have been calculated for CeCl 3 -LnCl 3 -H 2 O systems (where Ln identical with Sm, Gd, Dy, Ho, Er, Y) containing solid solutions of types IV and IVa. It is shown that the stability of the solid solutions decreases with increasing difference between the radii of the cations of cerium and the second lanthanide, which enter into the composition of the components of the solid solutions. The factors determining the composition of a liquid solution corresponding to the eutonic point are specified

Structural analysis and magnetic properties of solid solutions of Co–Cr system obtained by mechanical alloying

Energy Technology Data Exchange (ETDEWEB)

Betancourt-Cantera, J.A. [Área Académica de Ciencias de la Tierra y Materiales, UAEH Carr., Pachuca-Tulancingo Km. 4.5, Pachuca, Hidalgo 42184 (Mexico); Sánchez-De Jesús, F., E-mail: fsanchez@uaeh.edu.mx [Área Académica de Ciencias de la Tierra y Materiales, UAEH Carr., Pachuca-Tulancingo Km. 4.5, Pachuca, Hidalgo 42184 (Mexico); Bolarín-Miró, A.M. [Área Académica de Ciencias de la Tierra y Materiales, UAEH Carr., Pachuca-Tulancingo Km. 4.5, Pachuca, Hidalgo 42184 (Mexico); Betancourt, I.; Torres-Villaseñor, G. [Departamento de Materiales Metálicos y Cerámicos, Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, México D.F. 04510 (Mexico)

2014-03-15

In this paper, a systematic study on the structural and magnetic properties of Co{sub 100−x}Cr{sub x} alloys (0solid solutions based on Co-hcp, Co-fcc and Cr-bcc structures were obtained. The saturation polarization indicated a maximum value of 1.17 T (144 Am{sup 2}/kg) for the Co{sub 90}Cr{sub 10}, which decreases with the increasing of the Cr content up to x=80, as a consequence of the dilution effect of the magnetic moment which is caused by the Cr content and by the competition between ferromagnetic and antiferromagnetic exchange interactions. The coercivity increases up to 34 kA/m (435 Oe) for Co{sub 40}Cr{sub 60}. For Cr rich compositions, it is observed an important decrease reaching 21 kA/m (272 Oe) for Co{sub 10}Cr{sub 90,} it is related to the grain size and the structural change. Besides, the magnetic anisotropy constant was determined for each composition. Magnetic thermogravimetric analysis allowed to obtain Curie temperatures corresponding to the formation of hcp-Co(Cr) and fcc-Co(Cr) solid solutions. - Highlights: • Mechanical alloying (MA) induces the formation of solid solutions of Co–Cr system in non-equilibrium. • We report the crystal structure and the magnetic behavior of Co–Cr alloys produced by MA. • MA improves the magnetic properties of Co–Cr system.

Solid lipid nanoparticles suspension versus commercial solutions for dermal delivery of minoxidil.

Science.gov (United States)

Padois, Karine; Cantiéni, Céline; Bertholle, Valérie; Bardel, Claire; Pirot, Fabrice; Falson, Françoise

2011-09-15

Solid lipid nanoparticles have been reported as possible carrier for skin drug delivery. Solid lipid nanoparticles are produced from biocompatible and biodegradable lipids. Solid lipid nanoparticles made of semi-synthetic triglycerides stabilized with a mixture of polysorbate and sorbitan oleate were loaded with 5% of minoxidil. The prepared systems were characterized for particle size, pH and drug content. Ex vivo skin penetration studies were performed using Franz-type glass diffusion cells and pig ear skin. Ex vivo skin corrosion studies were realized with a method derived from the Corrositex(®) test. Solid lipid nanoparticles suspensions were compared to commercial solutions in terms of skin penetration and skin corrosion. Solid lipid nanoparticles suspensions have been shown as efficient as commercial solutions for skin penetration; and were non-corrosive while commercial solutions presented a corrosive potential. Solid lipid nanoparticles suspensions would constitute a promising formulation for hair loss treatment. Copyright © 2011 Elsevier B.V. All rights reserved.

1H NMR quantification in very dilute toxin solutions: application to anatoxin-a analysis.

Science.gov (United States)

Dagnino, Denise; Schripsema, Jan

2005-08-01

A complete procedure is described for the extraction, detection and quantification of anatoxin-a in biological samples. Anatoxin-a is extracted from biomass by a routine acid base extraction. The extract is analysed by GC-MS, without the need of derivatization, with a detection limit of 0.5 ng. A method was developed for the accurate quantification of anatoxin-a in the standard solution to be used for the calibration of the GC analysis. 1H NMR allowed the accurate quantification of microgram quantities of anatoxin-a. The accurate quantification of compounds in standard solutions is rarely discussed, but for compounds like anatoxin-a (toxins with prices in the range of a million dollar a gram), of which generally only milligram quantities or less are available, this factor in the quantitative analysis is certainly not trivial. The method that was developed can easily be adapted for the accurate quantification of other toxins in very dilute solutions.

Physical and chemical stability of reconstituted and diluted dexrazoxane infusion solutions.

Science.gov (United States)

Zhang, Yan-Ping; Myers, Alan L; Trinh, Van A; Kawedia, Jitesh D; Kramer, Mark A; Benjamin, Robert S; Tran, Hai T

2014-02-01

Dexrazoxane is used clinically to prevent anthracycline-associated cardiotoxicity. Hydrolysis of dexrazoxane prior to reaching the cardiac membranes severely hampers its mode of action; therefore, degradation during the preparation and administration of intravenous dexrazoxane admixtures demands special attention. Moreover, the ongoing national shortage of one dexrazoxane formulation in the United States has forced pharmacies to dispense other commercially available dexrazoxane products. However, the manufacturers' limited stability data restrict the flexibility of dexrazoxane usage in clinical practice. The aims of this study are to determine the physical and chemical stability of reconstituted and diluted solutions of two commercially available dexrazoxane formulations. The stability of two dexrazoxane products, brand and generic name, in reconstituted and intravenous solutions stored at room temperature without light protection in polyvinyl chloride bags was determined. The concentrations of dexrazoxane were measured at predetermined time points up to 24 h using a validated reversed phase high-performance liquid chromatography with ultraviolet detection assay. Brand (B-) and generic (G-) dexrazoxane products, reconstituted in either sterile water or 0.167 M sodium lactate (final concentration of 10 mg/mL), were found stable for at least to 8 h. Infusion solutions of B-dexrazoxane, prepared according to each manufacturer's directions, were stable for at least 24 h and 8 h at 1 mg/mL and 3 mg/mL, respectively. Infusion solutions of G-dexrazoxane, prepared in either 5% dextrose or 0.9% sodium chloride following the manufacturer's guidelines, were also stable for at least 24 h and 8 h at 1 mg/mL and 3 mg/mL, respectively. All tested solutions were found physically stable up to 24 h at room temperature. The stability of dexrazoxane infusion solutions reported herein permits advance preparation of dexrazoxane intravenous admixtures, facilitating

Low temperature kinetics of In-Cd solid solution decomposition

Czech Academy of Sciences Publication Activity Database

Pal-Val, P.P.; Pal-Val, L.N.; Ostapovets, A.A.; Vaněk, Přemysl

2008-01-01

Roč. 137, - (2008), s. 35-42 ISSN 1012-0394 Institutional research plan: CEZ:AV0Z10100520 Keywords : low temperatures * In-based alloys * solid solutions * isothermal structure instability * Young's modulus * electrical resistivity * phase diagrams Subject RIV: BM - Solid Matter Physics ; Magnetism http://www.scientific.net/3-908451-53-1/35/

Static and dynamic light scattering studies on dilute polyrotaxane solutions

International Nuclear Information System (INIS)

Kume, Tetsuya; Sakai, Yasuhiro; Mayumi, Koichi; Kidowaki, Masatoshi; Yokoyama, Hideaki; Ito, Kohzo; Araki, Jun

2009-01-01

Static and dynamic light scattering measurements were performed for dilute polyrotaxane solutions in different types of solvent systems, i.e. dimethylacetamide (DMAc) or dimethylformamide (DMF) containing 1-6 wt% lithium chloride (LiCl), 1 M aqueous sodium hydroxide (NaOH) and dimethylsulfoxide (DMSO). No aggregation of the polyrotaxane in DMF/LiCl was confirmed in the present study. Radius of gyration of the dissolved polyrotaxane was largest in NaOHaq., followed by values in amide solvents/LiCl and that in DMSO, and was probably dominated not by Coulombic repulsion but by the mutual affinity between solvent and polyrotaxane. Ratio of radius of gyration to hydrodynamic radius suggested the flexible random-coiled conformation in DMSO and relatively more extended, semi-flexible ones in amide solvents/LiCl and NaOHaq. The obtained values of second virial coefficient and weight average molecular weight seemed to be affected by a potential change in differential refractive index increments, caused by selective macrocationization or ionization.

Static and dynamic light scattering studies on dilute polyrotaxane solutions

Science.gov (United States)

Kume, Tetsuya; Araki, Jun; Sakai, Yasuhiro; Mayumi, Koichi; Kidowaki, Masatoshi; Yokoyama, Hideaki; Ito, Kohzo

2009-08-01

Static and dynamic light scattering measurements were performed for dilute polyrotaxane solutions in different types of solvent systems, i.e. dimethylacetamide (DMAc) or dimethylformamide (DMF) containing 1-6 wt% lithium chloride (LiCl), 1 M aqueous sodium hydroxide (NaOH) and dimethylsulfoxide (DMSO). No aggregation of the polyrotaxane in DMF/LiCl was confirmed in the present study. Radius of gyration of the dissolved polyrotaxane was largest in NaOHaq., followed by values in amide solvents/LiCl and that in DMSO, and was probably dominated not by Coulombic repulsion but by the mutual affinity between solvent and polyrotaxane. Ratio of radius of gyration to hydrodynamic radius suggested the flexible random-coiled conformation in DMSO and relatively more extended, semi-flexible ones in amide solvents/LiCl and NaOHaq. The obtained values of second virial coefficient and weight average molecular weight seemed to be affected by a potential change in differential refractive index increments, caused by selective macrocationization or ionization.

Dislocation cross-slip in fcc solid solution alloys

International Nuclear Information System (INIS)

Nöhring, Wolfram Georg; Curtin, W.A.

2017-01-01

Cross-slip is a fundamental process of screw dislocation motion and plays an important role in the evolution of work hardening and dislocation structuring in metals. Cross-slip has been widely studied in pure FCC metals but rarely in FCC solid solutions. Here, the cross-slip transition path in solid solutions is calculated using atomistic methods for three representative systems of Ni-Al, Cu-Ni and Al-Mg over a range of solute concentrations. Studies using both true random alloys and their corresponding average-alloy counterparts allow for the independent assessment of the roles of (i) fluctuations in the spatial solute distribution in the true random alloy randomness and (ii) average alloy properties such as stacking fault energy. The results show that the solute fluctuations dominate the activation energy barrier, i.e. there are large sample-to-sample variations around the average activation barrier. The variations in activation barrier correlate linearly with the energy difference between the initial and final states. The distribution of this energy difference can be computed analytically in terms of the solute/dislocation interaction energies. Thus, the distribution of cross-slip activation energies can be accurately determined from a parameter-free analytic model. The implications of the statistical distribution of activation energies on the rate of cross-slip in real alloys are then identified.

Phase segregation in cerium-lanthanum solid solutions

NARCIS (Netherlands)

Belliere, V.; Joorst, G; Stephan, O; de Groot, FMF; Weckhuysen, BM

2006-01-01

Electron energy-loss spectroscopy (EELS) in combination with scanning transmission electron microscopy ( STEM) reveals that the La enrichment at the surface of cerium-lanthanum solid solutions is an averaged effect and that segregation occurs in a mixed oxide phase. This separation occurs within a

Geochemical and numerical modelling of interactions between solid solutions and an aqueous solution. Extension of a reactive transport computer code called Archimede and application to reservoirs diagenesis; Modelisation geochimique et numerique des interactions entre des solutions solides et une solution aqueuse: extension du logiciel de reaction-transport archimede et application a la diagenese des reservoirs

Energy Technology Data Exchange (ETDEWEB)

Nourtier-Mazauric, E.

2003-03-15

This thesis presents a thermodynamic and kinetic model of interactions between a fluid and ideal solid solutions represented by several end-members. The reaction between a solid solution and the aqueous solution results from the competition between the stoichiometric dissolution of the initial solid solution and the co-precipitation of the least soluble solid solution in the fluid at considered time. This model was implemented in ARCHIMEDE, a computer code of reactive transport in porous media, then applied to various examples. In the case of binary solid solutions, a graphical method allowed to determine the compositions of the precipitating solid solutions, with the aid of the end-member chemical potentials. The obtained program could be used to notably model the diagenesis of clayey or carbonated oil reservoirs, or the ground pollutant dispersion. (author)

A conductance study of guanidinium chloride, thiocyanate, sulfate, and carbonate in dilute aqueous solutions: ion-association and carbonate hydrolysis effects.

Science.gov (United States)

Hunger, Johannes; Neueder, Roland; Buchner, Richard; Apelblat, Alexander

2013-01-17

We study the conductance of dilute aqueous solutions for a series of guandinium salts at 298.15 K. The experimental molar conductivities were analyzed within the framework of the Quint-Viallard theory in combination with Debye-Hückel activity coefficients. From this analysis, we find no evidence for significant ion association in aqueous solutions of guanidinium chloride (GdmCl) and guanidinium thiocyanate (GdmSCN), and the molar conductivity of these electrolytes can be modeled assuming a complete dissociation. The limiting ionic conductivity of the guanidinium ion (Gdm(+)) is accurately determined to λ(Gdm(+)) = 51.45 ± 0.10 S cm(2) mol(-1). For the bivalent salts guanidinium sulfate (Gdm(2)SO(4)) and guanidinium carbonate (Gdm(2)CO(3)), the molar conductivities show small deviations from ideal (fully dissociated electrolyte) behavior, which are related to weak ion association in solution. Furthermore, for solutions of Gdm(2)CO(3), the hydrolysis of the carbonate anion leads to distinctively increased molar conductivities at high dilutions. The observed ion association is rather weak for all studied electrolytes and cannot explain the different protein denaturing activities of the studied guanidinium salts, as has been proposed previously.

Synthesis, characterization and thermal expansion studies on thorium-praseodymium mixed oxide solid solutions

International Nuclear Information System (INIS)

Panneerselvam, G.; Antony, M.P.; Srinivasan, T.G.; Vasudeva Rao, P.R.

2010-01-01

Full text: Thorium-praseodymium mixed oxide solid solutions containing 15, 25, 40 and 55 mole percent of praseodymia were synthesized by mixing the solutions of thorium nitrate in water and praseodymium oxide (Pr 6 O 11 ) in conc. HNO 3 . Subsequently, their hydroxides were co-precipitated by the addition of aqueous ammonia. Further the precipitate was dried at 50 deg C, calcined at 600 deg C for 4 hours and sintered at 1200 deg C for 6 h in air. X-ray diffraction measurements were performed for phase identification and lattice parameter derivation. Single-phase fluorite structure was observed for all the compositions. Bulk and theoretical densities of solid solutions were also determined by immersion and X-ray techniques. Thermal expansion coefficients and percentage linear thermal expansion of the solid solutions were determined using high temperature X-ray diffraction technique in the temperature range 300 to 1700 K for the first time. The room temperature lattice constants estimated for above compositions are 0.5578, 0.5565, 0.5545 and 0.5526 nm, respectively. The mean linear thermal expansion coefficients for the solid solutions are 15.48 x 10 -6 K -1 , 18.35 x 10 -6 K -1 , 22.65 x 10 -6 K -1 and 26.95 x 10 -6 K -1 , respectively. The percentage linear thermal expansions in this temperature range are 1.68, 1.89, 2.21 and 2.51 respectively. It is seen that the solid solutions are stable up to 1700 K. It is also seen that the effect and nature of the dopant are the important parameters influencing the thermal expansion of the ThO 2 . The lattice parameter of the solid solutions exhibited a decreasing trend with respect to praseodymia addition. The percentage linear thermal expansion of the solid solutions increases steadily with increasing temperature

All-proportional solid-solution Rh–Pd–Pt alloy nanoparticles by femtosecond laser irradiation of aqueous solution with surfactant

Energy Technology Data Exchange (ETDEWEB)

Sarker, Md. Samiul Islam, E-mail: samiul-phy@ru.ac.bd; Nakamura, Takahiro; Sato, Shunichi [Tohoku University, Institute of Multidisciplinary Research for Advanced Materials (Japan)

2015-06-15

Formation of Rh–Pd–Pt solid-solution alloy nanoparticles (NPs) by femtosecond laser irradiation of aqueous solution in the presence of polyvinylpyrrolidone (PVP) or citrate as a stabilizer was studied. It was found that the addition of surfactant (PVP or citrate) significantly contributed to reduce the mean size of the particles to 3 nm for PVP and 10 nm for citrate, which was much smaller than that of the particles fabricated without any surfactants (20 nm), and improved the dispersion state as well as the colloidal stability. The solid-solution formation of the Rh–Pd–Pt alloy NPs was confirmed by the XRD results that the diffraction pattern was a single peak, which was found between the positions corresponding to each pure Rh, Pd, and Pt NPs. Moreover, all the elements were homogeneously distributed in every particle by STEM-EDS elemental mapping, strongly indicating the formation of homogeneous solid-solution alloy. Although the Rh–Pd–Pt alloy NPs fabricated with PVP was found to be Pt rich by EDS observation, the composition of NPs fabricated with citrate almost exactly preserved the feeding ratio of ions in the mixed solution. To our best knowledge, these results demonstrated for the first time, the formation of all-proportional solid-solution Rh–Pd–Pt alloy NPs with well size control.

Ab initio identified design principles of solid-solution strengthening in Al

International Nuclear Information System (INIS)

Ma Duancheng; Friák, Martin; Pezold, Johann von; Raabe, Dierk; Neugebauer, Jörg

2013-01-01

Solid-solution strengthening in six Al–X binary systems is investigated using first-principle methods. The volumetric mismatch parameter and the solubility enthalpy per solute were calculated. We derive three rules for designing solid-solution strengthened alloys: (i) the solubility enthalpy per solute is related to the volumetric mismatch by a power law; (ii) for each annealing temperature, there exists an optimal solute–volume mismatch to achieve maximum strength; and (iii) the strengthening potential of high volumetric mismatch solutes is severely limited by their low solubility. Our results thus show that the thermodynamic properties of the system (here Al–X alloys) set clear upper bounds to the achievable strengthening effects owing to the reduced solubility with increasing volume mismatch. (paper)

Thermodynamic properties of solid solutions in the system Ag2S–Ag2Se

International Nuclear Information System (INIS)

Pal’yanova, G.A.; Chudnenko, K.V.; Zhuravkova, T.V.

2014-01-01

We have summarized experimental data on the phase diagram of the system Ag 2 S–Ag 2 Se. Standard thermodynamic functions of four solid solutions in this system have been calculated using the model of regular and subregular solutions: a restricted fcc solid solution γ-Ag 2 S-Ag 2 S 1−x Se x (x 2 S–Ag 2 Se, monoclinic solid solution (α) from Ag 2 S to Ag 2 S 0.4 Se 0.6 , and orthorhombic solid solution (α) from Ag 2 S 0.3 Se 0.7 to the Ag 2 Se. G mix and S mix have been evaluated using the subregular model for asymmetric solution for the region Ag 2 S 0.4 Se 0.6 –Ag 2 S 0.3 Se 0.7 . The thermodynamic data can be used for modeling in complex natural systems and in matters of semiconductor materials

Diffusion kinetics and spinodal decay of quasi-equilibrium solid solutions

International Nuclear Information System (INIS)

Zakharov, M.A.

2000-01-01

Phenomenological theory for rearrangement of solid solutions with the hierarchy of the component atomic mobilities is elaborated in the approximation of the local equilibrium. The hydrodynamic stage of the evolution of these solutions is studied as a sequence of quasi-equilibrium states characterized by implementation of some conditions of the total equilibrium. On the basis of separation of fast and slow constituents of diffusion and on the basis of the method of reduced description one derived equation for evolution of separations of fast components in quasi-equilibrium solid solutions at the arbitrary stages of rearrangement in terms of the generalized lattice model taking account of the proper volumes of the components. The conditions of the stability of quasi-equilibrium solutions to the spinodal decomposition are determined and the equations of metastability boundaries of such systems are derived [ru

Solid solution in Al-4.5 wt% Cu produced by mechanical alloying

International Nuclear Information System (INIS)

Fogagnolo, J.B.; Amador, D.; Ruiz-Navas, E.M.; Torralba, J.M.

2006-01-01

Mechanical alloying has been used to produce oxide dispersion strengthened alloys, intermetallic compounds, aluminium alloys and to obtain nanostructured and amorphous materials, as well as to extend the solid solution limit. In this work, Al and Cu elemental powders were subjected to high-energy milling to produce Al-4.5 wt% Cu powder alloy. The powders obtained were characterized by scanning electron microscopy, X-ray diffraction (XRD) and differential scanning calorimetry (DSC), aiming to explore if the copper is present in solid solution or as small particles after high-energy milling. Related to the formation of a supersaturated solid solution, the results of scanning electron microscopy and X-ray diffraction are non-conclusive: the copper could be dispersed with a very small size, undetectable to both techniques. The Al 2 Cu precipitation at temperatures between 160 and 230 deg. C, verified by DSC and XRD analyses, substantiated that mechanical alloying had produced a supersaturated solid solution of copper in aluminium. The crystallite size as a function of milling time and annealing temperature was also determined by X-ray techniques

Mechanism of pitting corrosion prevention by nitrite in carbon steel exposed to dilute salt solutions. 1998 annual progress report

International Nuclear Information System (INIS)

Zapp, P.E.; Zee, J. van.

1998-01-01

'The overall goal of this project is to develop a fundamental understanding of the role of nitrite in preventing the breakdown of protective oxide(s) on carbon steel and the onset of pitting. Pitting corrosion of carbon steel exposed to dilute alkaline salt solutions can be induced by nitrate, sulfate, and chloride ions and is prevented by sufficient concentration of nitrite. A significant example of this material/electrolyte system is the storage and processing of DOE''s high-level radioactive liquid waste in carbon steel tanks. Added nitrite in the waste has a considerable downstream impact on the immobilization of the waste in a stable glass form. Waste tank integrity and glass production efficiency may benefit from the fundamental understanding of nitrite''s role in preventing pitting. This report summarizes progress after approximately six months of effort in this three-year EMSP project. Initial experimental and theoretical work has focused on the electrochemical behavior of carbon steel in simplified non-radioactive solutions that simulate complex dilute radioactive waste solutions. These solutions contain corrosion-inducing species such as nitrate and chloride and the corrosion-inhibiting nitrite at moderately alkaline pHs. The electrochemical behavior of interest here is that of the open-circuit potential of the steel specimen at equilibrium in the experimental electrolyte and the measures of the steel''s passivity and passivity breakdown.'

Volumetric properties of ascorbic acid (vitamin C) and thiamine hydrochloride (vitamin B1) in dilute HCl and in aqueous NaCl solutions at (283.15, 293.15, 298.15, 303.15, 308.15, and 313.15) K

International Nuclear Information System (INIS)

Ayranci, Guler; Sahin, Melike; Ayranci, Erol

2007-01-01

Apparent molar volumes and apparent molar isentropic compressibilities of ascorbic acid (vitamin C) and thiamine hydrochloride (vitamin B 1 ) were determined from accurately measured density and sound velocity data in water and in aqueous NaCl solutions at (283.15, 293.15, 298.15, 303.15, 308.15, and 313.15) K. These volume and compressibility data were extrapolated to zero concentration using suitable empirical or theoretical equations to determine the corresponding infinite dilution values. Apparent molar expansibilities at infinite dilution were determined from slopes of apparent molar volume vs. temperature plots. Ionization of both ascorbic acid and thiamine hydrochloride were suppressed using sufficiently acidic solutions. Apparent molar volumes at infinite dilution for ascorbic acid and thiamine hydrochloride were found to increase with temperature in acidic solutions and in the presence of co-solute, NaCl. Apparent molar expansibility at infinite dilution were found to be constant over the temperature range studied and were all positive, indicating the hydrophilic character of the two vitamins studied in water and in the presence of co-solute, NaCl. Apparent molar isentropic compressibilities of ascorbic acid at infinite dilution were positive in water and in the presence of co-solute, NaCl, at low molalities. Those of thiamine hydrochloride at infinitive dilution were all negative, consistent with its ionic nature. Transfer apparent molar volumes of vitamins at infinite dilution from water solutions to NaCl solutions at various temperatures were determined. The results were interpreted in terms of complex vitamin-water-co-solute (NaCl) interactions

Ion Transport in Confined Geometries below the Nanoscale: Access Resistance Dominates Protein Channel Conductance in Diluted Solutions.

Science.gov (United States)

Alcaraz, Antonio; López, M Lidón; Queralt-Martín, María; Aguilella, Vicente M

2017-10-24

Synthetic nanopores and mesoscopic protein channels have common traits like the importance of electrostatic interactions between the permeating ions and the nanochannel. Ion transport at the nanoscale occurs under confinement conditions so that the usual assumptions made in microfluidics are challenged, among others, by interfacial effects such as access resistance (AR). Here, we show that a sound interpretation of electrophysiological measurements in terms of channel ion selective properties requires the consideration of interfacial effects, up to the point that they dominate protein channel conductance in diluted solutions. We measure AR in a large ion channel, the bacterial porin OmpF, by means of single-channel conductance measurements in electrolyte solutions containing varying concentrations of high molecular weight PEG, sterically excluded from the pore. Comparison of experiments performed in charged and neutral planar membranes shows that lipid surface charges modify the ion distribution and determine the value of AR, indicating that lipid molecules are more than passive scaffolds even in the case of large transmembrane proteins. We also found that AR may reach up to 80% of the total channel conductance in diluted solutions, where electrophysiological recordings register essentially the AR of the system and depend marginally on the pore characteristics. These findings may have implications for several low aspect ratio biological channels that perform their physiological function in a low ionic strength and macromolecule crowded environment, just the two conditions enhancing the AR contribution.

Ionic liquids behave as dilute electrolyte solutions

Science.gov (United States)

Gebbie, Matthew A.; Valtiner, Markus; Banquy, Xavier; Fox, Eric T.; Henderson, Wesley A.; Israelachvili, Jacob N.

2013-01-01

We combine direct surface force measurements with thermodynamic arguments to demonstrate that pure ionic liquids are expected to behave as dilute weak electrolyte solutions, with typical effective dissociated ion concentrations of less than 0.1% at room temperature. We performed equilibrium force–distance measurements across the common ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C4mim][NTf2]) using a surface forces apparatus with in situ electrochemical control and quantitatively modeled these measurements using the van der Waals and electrostatic double-layer forces of the Derjaguin–Landau–Verwey–Overbeek theory with an additive repulsive steric (entropic) ion–surface binding force. Our results indicate that ionic liquids screen charged surfaces through the formation of both bound (Stern) and diffuse electric double layers, where the diffuse double layer is comprised of effectively dissociated ionic liquid ions. Additionally, we used the energetics of thermally dissociating ions in a dielectric medium to quantitatively predict the equilibrium for the effective dissociation reaction of [C4mim][NTf2] ions, in excellent agreement with the measured Debye length. Our results clearly demonstrate that, outside of the bound double layer, most of the ions in [C4mim][NTf2] are not effectively dissociated and thus do not contribute to electrostatic screening. We also provide a general, molecular-scale framework for designing ionic liquids with significantly increased dissociated charge densities via judiciously balancing ion pair interactions with bulk dielectric properties. Our results clear up several inconsistencies that have hampered scientific progress in this important area and guide the rational design of unique, high–free-ion density ionic liquids and ionic liquid blends. PMID:23716690

Hydrothermal crystallization of zirconia and zirconia solid solutions

International Nuclear Information System (INIS)

Pyda, W.; Haberko, K.; Bucko, M.M.

1991-01-01

Zirconia as well as yttria-zirconia and calcia-zirconia solid-solution powders were crystallized under hydrothermal conditions from (co)precipitated hydroxides. The morphology of the power particles is strongly dependent on the crystallization conditions. The powders crystallized in a water solution of Na, K, and Li hydroxides show elongated particles of much larger sizes than those which result from the process carried out in pure water or a water solution of Na, K, or Li chlorides. The shapes of the latter particles are isometric. In this paper the growth mechanism of the elongated particles is suggested

Activity coefficients at infinite dilution of organic solutes in N-alkylpyridinium bis(trifluoromethylsulfonyl)imide ([CnPY][NTf2], n = 2, 4, 5) using gas-liquid chromatography

International Nuclear Information System (INIS)

Yan Peifang; Liu Qingshan; Yang Miao; Liu Xiumei; Tan Zhicheng; Welz-Biermann, Urs

2010-01-01

The activity coefficients at infinite dilution, γ i ∞ for both polar and non-polar solutes in the ionic liquids N-alkylpyridinium bis(trifluoromethylsulfonyl)imide ([C n PY][NTf 2 ], n = 2, 4, 5) have been determined by gas-liquid chromatography using the ionic liquid as the stationary phase. The measurements were carried out at the temperatures from (303 to 353) K. The partial molar excess enthalpies at infinite dilution H i E,∞ of the solutes in the ionic liquids were also derived from the temperature dependence of the γ i ∞ values. The values of the selectivity for the hexane/benzene and cyclohexane/benzene separation problems were calculated from experimental infinite dilution activity coefficient values and compared to the other ionic liquids, taken from the recent literatures.

Magnetic clusters in ilmenite-hematite solid solutions

DEFF Research Database (Denmark)

Frandsen, Cathrine; Burton, B. P.; Rasmussen, Helge Kildahl

2010-01-01

We report the use of high-field 57Fe Mössbauer spectroscopy to resolve the magnetic ordering of ilmenite-hematite [xFeTiO3−(1−x)Fe2O3] solid solutions with x>0.5. We find that nanometer-sized hematite clusters exist within an ilmenite-like matrix. Although both phases are antiferromagnetically...

Experimental considerations on producing highly polarized liquid 3He in a matrix of solid 4He

International Nuclear Information System (INIS)

Greenberg, A.S.; Hebral, B.; Papoular, M.; Beal-Monod, M.T.

1980-01-01

Two experiments are briefly reviewed in which droplets of 3 He were formed in solid 4 He. These experiments indicate such conditions are favorable for the production of quasi-stable highly polarized liquid 3 He. A solid solution of dilute 3 He in 4 He is proposed as a promising system to produce experimentally realizable highly polarized liquid 3 He using the Castaing-Nozieres decompression

EPR of gamma irradiated solid sucrose and UV spectra of its solution. An attempt for calibration of solid state/EPR dosimetry

International Nuclear Information System (INIS)

Yordanov, N.D.; Karakirova, Y.

2007-01-01

A simple new approach for independent calibration of solid state/EPR (SS/EPR) dosimetry system is reported. It is based on the fact that: (i) gamma-irradiation of solid sucrose (sugar) induces stable EPR detectable free radicals accompanied by UV detectable brown colour stable in the solid state and in solution; (ii) both the EPR intensity of gamma-irradiated solid sucrose and its solution UV absorbance linearly depend on the absorbed dose high energy radiation and may be independently used for dosimetric purpose; (iii) UV spectrometers are calibrated. The correlation between EPR response and absorbed dose radiation of solid sucrose and UV absorption of its solutions is used in the present communication for calibration purpose. The procedure of sucrose extraction from sucrose-paraffin dosimeters is described. The calibration procedure may be applied to any other (alanine, self-calibrated, etc.) SS/EPR dosimeters, simultaneously irradiated with sucrose

Dilute acid/metal salt hydrolysis of lignocellulosics

Science.gov (United States)

Nguyen, Quang A.; Tucker, Melvin P.

2002-01-01

A modified dilute acid method of hydrolyzing the cellulose and hemicellulose in lignocellulosic material under conditions to obtain higher overall fermentable sugar yields than is obtainable using dilute acid alone, comprising: impregnating a lignocellulosic feedstock with a mixture of an amount of aqueous solution of a dilute acid catalyst and a metal salt catalyst sufficient to provide higher overall fermentable sugar yields than is obtainable when hydrolyzing with dilute acid alone; loading the impregnated lignocellulosic feedstock into a reactor and heating for a sufficient period of time to hydrolyze substantially all of the hemicellulose and greater than 45% of the cellulose to water soluble sugars; and recovering the water soluble sugars.

Electron magnetic resonance of diluted solid solutions of Gd{sup 3+} in SrTiO{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Biasi, R.S. de, E-mail: rsbiasi@ime.eb.br [Secao de Engenharia Mecanica e de Materiais, Instituto Militar de Engenharia, 22290-270 Rio de Janeiro, RJ (Brazil); Grillo, M.L.N., E-mail: mluciag@uerj.br [Instituto de Fisica, Universidade do Estado do Rio de Janeiro, 20550-013 Rio de Janeiro, RJ (Brazil)

2011-10-17

Highlights: {yields} EMR is an effective method to study the range of the exchange interaction in solid solutions. {yields} The range of the exchange interaction between Gd{sup 3+} ions in SrTiO{sub 3} is about 0.96 nm. {yields} The linewidth increases faster with Gd concentration in SrTiO{sub 3} than in other host lattices, such as CeO{sub 2}, SrO, CaO and ZrSiO{sub 4}. - Abstract: Electron magnetic resonance (EMR) spectra of gadolinium-doped strontium titanate (SrTiO{sub 3}) have been studied at room temperature for gadolinium concentrations between 0.20 and 1.20 mol%. The results suggest that the Gd{sup 3+} ions occupy substitutional sites, replacing the Sr{sup 2+} ion, that the electron magnetic resonance linewidth increases with increasing gadolinium concentration and that the range of the exchange interaction between Gd{sup 3+} ions is about 0.96 nm, of the same order as that of the same ion in other host lattices, such as ceria (CeO{sub 2}), quicklime (CaO), strontia (SrO) and zircon (ZrSiO{sub 4}). The fact that the electron magnetic resonance linewidth of the Gd{sup 3+} ion increases, regularly and predictably, with Gd concentration, shows that the Gd{sup 3+} ion can be used as a probe to study, rapidly and non-destructively, the crystallinity and degradation of SrTiO{sub 3}.

Dilute and Semidilute Solutions of a Nonionic, Rigid, Water-soluble Polymer

Science.gov (United States)

Russo, Paul; Huberty, Wayne; Zhang, Donghui; Water-Soluble Rodlike Polymer Team Collaboration

2014-03-01

The solution physics of random polymer chains was established largely on the behavior of commercial polymers such as polystyrene for organic solvents or nonionic poly(ethyleneoxide) for aqueous solvents. Not only are these materials widely available for industrial use, they can be synthesized to be essentially monodisperse. When it comes to stiff polymers, good choices are few and less prone to be used in industrial applications. Much was learned from polypeptides such as poly(benzylglutamate) or poly(stearylglutamate) in polar organic solvents and nonpolar organic solvents, respectively, but aqueous systems generally require charge. Poly(Nɛ-2-[2-(2-Methoxyethoxy) ethoxy]acetyl-L-Lysine) a.k.a. PEGL was pioneered by Deming and coworkers. In principle, PEGL provides a convenient platform from which to study stiff polymer behavior--phase relations, dynamics, liquid crystal formation and gelation--all with good molecular weight control and uniformity and without electrical charge. Still, a large gap in knowledge exists between PEGL and traditional rodlike polymer systems. To narrow this gap, dynamic and static scattering, circular dichroism, and viscosity measurements have been made in dilute and semidilute solutions as necessary preliminaries for lyotropic liquid crystalline and gel phases. Supported by NSF DMR 1306262. Department of Chemistry and Macromolecular Studies Group. Current address: Georgia Institute of Technology, School of Materials Science and Engineering.

The elastic solid solution model for minerals at high pressures and temperatures

Science.gov (United States)

Myhill, R.

2018-02-01

Non-ideality in mineral solid solutions affects their elastic and thermodynamic properties, their thermobaric stability, and the equilibrium phase relations in multiphase assemblages. At a given composition and state of order, non-ideality in minerals is typically modelled via excesses in Gibbs free energy which are either constant or linear with respect to pressure and temperature. This approach has been extremely successful when modelling near-ideal solutions. However, when the lattice parameters of the solution endmembers differ significantly, extrapolations of thermodynamic properties to high pressures using these models may result in significant errors. In this paper, I investigate the effect of parameterising solution models in terms of the Helmholtz free energy, treating volume (or lattice parameters) rather than pressure as an independent variable. This approach has been previously applied to models of order-disorder, but the implications for the thermodynamics and elasticity of solid solutions have not been fully explored. Solid solution models based on the Helmholtz free energy are intuitive at a microscopic level, as they automatically include the energetic contribution from elastic deformation of the endmember lattices. A chemical contribution must also be included in such models, which arises from atomic exchange within the solution. Derivations are provided for the thermodynamic properties of n-endmember solutions. Examples of the use of the elastic model are presented for the alkali halides, pyroxene, garnet, and bridgmanite solid solutions. Elastic theory provides insights into the microscopic origins of non-ideality in a range of solutions, and can make accurate predictions of excess enthalpies, entropies, and volumes as a function of volume and temperature. In solutions where experimental data are sparse or contradictory, the Helmholtz free energy approach can be used to assess the magnitude of excess properties and their variation as a function

Influence of isotopic disorder on solid state amorphization and polyamorphism in solid H2O -D2O solutions

Science.gov (United States)

Gromnitskaya, E. L.; Danilov, I. V.; Lyapin, A. G.; Brazhkin, V. V.

2015-10-01

We present a low-temperature and high-pressure ultrasonic study of elastic properties of isotopic H2O-D2O solid solutions, comparing their properties with those of the isotopically pure H2O and D2O ices. Measurements were carried out for solid state amorphization (SSA) from 1h to high-density amorphous (HDA) ice upon compression up to 1.8 GPa at 77 K and for the temperature-induced (77 -190 K ) u-HDA (unrelaxed HDA) → e-HDA (expanded HDA) → low-density amorphous (LDA )→1 c cascade of ice transformations near room pressure. There are many similarities in the elasticity behaviour of H2O ,D2O , and H2O-D2O solid solutions, including the softening of the shear elastic modulus as a precursor of SSA and the HDA →LDA transition. We have found significant isotopic effects during H/D substitution, including elastic softening of H2O -D2O solid solutions with respect to the isotopically pure ices in the case of the bulk moduli of ices 1c and 1h and for both bulk and shear elastic moduli of HDA ice at high pressures (>1 GPa ) . This softening is related to the configurational isotopic disorder in the solid solutions. At low pressures, the isotope concentration dependence of the elastic moduli of u-HDA ice changes remarkably and becomes monotonic with pronounced change of the bulk modulus (≈20 %) .

Self-association of an indole based guanidinium-carboxylate-zwitterion: formation of stable dimers in solution and the solid state

Directory of Open Access Journals (Sweden)

Carolin Rether

2010-01-01

Full Text Available The indole based zwitterion 2 forms stable dimers held together by H-bond assisted ion pairs. Dimerisation was confirmed in the solid state and studied in solution using dilution NMR experiments. Even though zwitterion 2 forms very stable dimers even in DMSO, their stability is lower than of an analogous pyrrole based zwitterion 1. As revealed by the X-ray crystal structure the two binding sites in 2 cannot be planar due to steric interactions between the guanidinium group and a neighbouring aromatic CH. Hence the guanidinium moiety is twisted out of planarity from the rest of the molecule forcing the two monomers in dimer 2·2 to interact in a non-ideal orientation. Furthermore, the acidity of the NHs is lower than in 1 (as determined by UV-pH-titration also leading to less efficient binding interactions.

Contribution to the study of the structure of silver krypton solid solutions; Contribution a l'etude de la structure des solutions solides argent-krypton

Energy Technology Data Exchange (ETDEWEB)

Levy, V; Tullairet, J; Delaplace, J; Antolin-Baudier, J; Adda, Y [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1964-07-01

The silver-krypton solid solutions formed by electrical discharge have been studied by X-rays, electrical resistivity and electronic transmission microscopy. The crystalline parameter and residual resistivity measurements have shown that the krypton atom behaves very differently to those of other elements of the periodic classification when dissolved in silver. The recovery of the crystalline parameter and of the electrical resistivity has been studied as a function of temperature. (authors) [French] Les solutions solides argent, krypton, realisees par decharges electrique ont ete etudiees par Rayons X, resistivite electrique et microscopie electronique en transmission. Les mesures de parametre cristallin et de resistivite residuelle ont montre que le comportement de l'atome de krypton est tres different de celui des autres elements de la classification periodique en solution dans l'argent. La restauration du parametre cristallin et de la resistivite electrique en fonction de la temperature a ete etudiee. (auteurs)

Fluorimetrich determination of uranium in mineral samples and phosphoric solutions

International Nuclear Information System (INIS)

Pupo Gonzales, I.; Cuevillas, J.; Estevez, J.

1991-01-01

In this paper an analytical technique for the determination of uranium in different cuban minerals and acid leaching liquors of phosphorites is proposed. The method used for solid samples includes their disolution and further dilution of the solution obtained. For liquid samples dilution is the only intermediate step used. A study of HNO3 concentration (pH) was made in fluorimetric measurements. The method was applied to the uranium analysis in two IAEA standard reference samples (phosphate base), in natural phosphorites and a synthetic one, in clays and phosphoric liquors. The results agree with those obtained by other methods

Computationally efficient and quantitatively accurate multiscale simulation of solid-solution strengthening by ab initio calculation

International Nuclear Information System (INIS)

Ma, Duancheng; Friák, Martin; Pezold, Johann von; Raabe, Dierk; Neugebauer, Jörg

2015-01-01

We propose an approach for the computationally efficient and quantitatively accurate prediction of solid-solution strengthening. It combines the 2-D Peierls–Nabarro model and a recently developed solid-solution strengthening model. Solid-solution strengthening is examined with Al–Mg and Al–Li as representative alloy systems, demonstrating a good agreement between theory and experiments within the temperature range in which the dislocation motion is overdamped. Through a parametric study, two guideline maps of the misfit parameters against (i) the critical resolved shear stress, τ 0 , at 0 K and (ii) the energy barrier, ΔE b , against dislocation motion in a solid solution with randomly distributed solute atoms are created. With these two guideline maps, τ 0 at finite temperatures is predicted for other Al binary systems, and compared with available experiments, achieving good agreement

The growth and tensile deformation behavior of the silver solid solution phase with zinc

International Nuclear Information System (INIS)

Wu, Jiaqi; Lee, Chin C.

2016-01-01

The growth of homogeneous silver solid solution phase with zinc are conducted at two different compositions. X-ray diffraction (XRD) and Scanning electron microscope/Energy dispersive X-ray spectroscopy (SEM/EDX) are carried out for phase identification and chemical composition verification. The mechanical properties of silver solid solution phase with zinc are evaluated by tensile test. The engineering and true stress vs. strain curves are presented and analyzed, with those of pure silver in comparison. According to the experimental results, silver solid solution phase with zinc at both compositions show tempered yield strength, high tensile strength and large uniform strain compared to those of pure silver. Fractography further confirmed the superior ductility of silver solid solution phase with zinc at both compositions. Our preliminary but encouraging results may pave the way for the silver based alloys to be applied in industries such as electronic packaging and structure engineering.

Synthesis, characterization and thermal expansion studies on ThO2-SmO1.5 solid solutions

International Nuclear Information System (INIS)

Panneerselvam, G.; Antony, M.P.

2008-01-01

Full text: A highly homogeneous Th 1-x Sm x O 2 ; 0 ≤ x ≤ 0.8 solid solutions were synthesized by co-precipitation technique and the co-precipitated samples were sintered at 1473 K. Compositions of the solid solutions were characterized by standard wet-chemical analysis. X-ray diffraction measurements were performed in the sintered pellets for structural analysis, lattice parameter calculation and determination of solid solubility of SmO 1.5 in ThO 2 matrix. Bulk and theoretical densities of solid solutions were also determined. A fluorite structure was observed for ThO 2 -SmO 1.5 solid solutions with 0-55.2 mol % SmO 1.5 . Their thermal expansion coefficients were measured using high temperature X-ray diffraction technique. The mean linear thermal expansivity, αm for ThO 2 -SmO 1.5 solid solutions containing 17.9, 41.7 and 52.0 mole percent of SmO 1.5 were determined in the temperature range 298 to 2000 K for the first time. The mean linear thermal expansion coefficients for ThO 2 -SmO 1.5 solid solutions are 10.47x10 -6 K -1 , 11.16x10 -6 K -1 and 11.45x10 -6 K -1 , respectively. The percentage linear thermal expansion in this temperature range, for ThO 2 -SmO 1.5 solid solutions containing 17.9, 41.7 and 52.0 mol % SmO 1.5 are 1.82,1.94 and 1.99 respectively. It is suggested that the solid solutions are stable up to 2000 K. It is also suggested that the effect and nature of the dopant are the important parameters influenced in the thermal expansion of the ThO 2

Synthesis and characterization of type solid solution in the binary ...

Indian Academy of Sciences (India)

We have investigated Bi2O3–Eu2O3 binary system by doping with Eu2O3 in the composition range from 1 to 10 mole% via solid state reactions and succeeded to stabilize -Bi2O3 ... Our experimental observations strongly suggested that oxygen deficiency type non-stoichiometry is present in doped type solid solutions.

Bases for DOT exemption uranyl nitrate solution shipments

International Nuclear Information System (INIS)

Moyer, R.A.

1982-07-01

Uranyl nitrate solutions from a Savannah River Plant reprocessing facility have been transported in cargo tank trailers for more than 20 years without incident during transit. The solution is shipped to Oak Ridge for further processing and returned to SRP in a solid metal form for recycle. This solution, called uranyl nitrate hexahydrate (UNH) solution in Department of Transportation (DOT) regulations, is currently diluted about 2-fold to comply with DOT concentration limits (10% of low specific activity levels) specified for bulk low specific activity (LSA) liquid shipments. Dilution of the process solution increases the number of shipments, the cost of transportation, the cost of shipper preparations, the cost of further reprocessing in the receiving facility to first evaporate the added water, and the total risk to the population along the route of travel. However, the radiological risk remains about the same. Therefore, obtaining an exemption from DOT regulations to permit shipment of undiluted UNH solution, which is normally about two times the present limit, is prudent and more economical. The radiological and nonradiological risks from shipping a unit load of undiluted solution are summarized for the probable route. Data and calculations are presented on a per load or per shipment basis throughout this memorandum to keep it unclassified

The LiBH₄-LiI Solid Solution as an Electrolyte in an All-Solid-State Battery

DEFF Research Database (Denmark)

Sveinbjörnsson, Dadi Þorsteinn; Christiansen, Ane Sælland; Viskinde, Rasmus

2014-01-01

The charge and discharge performance of an all-solid-state lithium battery with the LiBH4-LiI solid solution as an electrolyte is reported. Lithium titanate (Li4Ti5O12) was used as the positive electrode and lithium metal as the negative electrode. The performance of the all-solid-state cell...

Theromdynamics of carbon in nickel-based multicomponent solid solutions

International Nuclear Information System (INIS)

Bradley, D.J.

1978-04-01

The activity coefficient of carbon in nickel, nickel-titanium, nickel-titanium-chromium, nickel-titanium-molybdenum and nickel-titanium-molybdenum-chromium alloys has been measured at 900, 1100 and 1215 0 C. The results indicate that carbon obeys Henry's Law over the range studied (0 to 2 at. percent). The literature for the nickel-carbon and iron-carbon systems are reviewed and corrected. For the activity of carbon in iron as a function of composition, a new relationship based on re-evaluation of the thermodynamics of the CO/CO 2 equilibrium is proposed. Calculations using this relationship reproduce the data to within 2.5 percent, but the accuracy of the calibrating standards used by many investigators to analyze for carbon is at best 5 percent. This explains the lack of agreement between the many precise sets of data. The values of the activity coefficient of carbon in the various solid solutions are used to calculate a set of parameters for the Kohler-Kaufman equation. The calculations indicate that binary interaction energies are not sufficient to describe the thermodynamics of carbon in some of the nickel-based solid solutions. The results of previous workers for carbon in nickel-iron alloys are completely described by inclusion of ternary terms in the Kohler-Kaufman equation. Most of the carbon solid solution at high temperatures in nickel and nickel-titantium alloys precipitates from solution on quenching in water. The precipitate is composed of very small particles (greater than 2.5 nm) of elemental carbon. The results of some preliminary thermomigration experiments are discussed and recommendations for further work are presented

Nanometric solid solutions of the fluorite and perovskite type crystal structures: Synthesis and properties

Directory of Open Access Journals (Sweden)

Snežana Bošković

2012-09-01

Full Text Available In this paper a short review of our results on the synthesis of nanosized CeO2, CaMnO3 and BaCeO3 solid solutions are presented. The nanopowders were prepared by two innovative methods: self propagating room temperature synthesis (SPRT and modified glycine/nitrate procedure (MGNP. Different types of solid solutions with rare earth dopants in concentrations ranging from 0–0.25 mol% were synthesized. The reactions forming solid solutions were studied. In addition, the characteristics of prepared nanopowders, phenomena during sintering and the properties of sintered samples are discussed.

Free energies of formation of WC and WzC and the thermodynamic properties of carbon in solid tungsten

Science.gov (United States)

Gupta, D. K.; Seigle, L. L.

1974-01-01

The activity of carbon in the two-phase regions - W + WC and W + W2C was obtained from the carbon content of iron rods equilibrated with mixtures of metal plus carbide powders. From this activity data the standard free energies of formation of WC and W2C were calculated. The temperature of the invariant reaction W2C = W + WC was fixed at 1570 + or - 5K. Using available solubility data for C in solid W, the partial molar free energy of C in the dilute solid solution was also calculated. The heat of solution of C in W, and the excess entropy for the interstitial solid solution, were computed, assuming that the carbon atoms reside in the octahedral interstices of bcc W.

Thermal conductivities of (ZrxPu(1-x)/2Am(1-x)/2)N solid solutions

International Nuclear Information System (INIS)

Nishi, Tsuyoshi; Takano, Masahide; Akabori, Mitsuo; Arai, Yasuo

2011-01-01

The thermal conductivity of Zr-based transuranium (TRU) nitride solid solutions is important for designing subcritical cores in nitride-fueled ADS. Some results have been reported concerning the thermal conductivities of (Zr,Pu)N. However, there have been no experimental data on the thermal conductivities of Zr-based nitride solid solutions containing MA. In this study, the authors prepared sintered samples of (Zr x Pu (1-x)/2 Am (1-x)/2) N (x=0.0, 0.58, 0.80) solid solutions. The thermal diffusivity and heat capacity of (Zr x Pu (1-x)/2 Am (1-x)/2) N solid solutions were measured using a laser flash method and drop calorimetry, respectively. Thermal conductivities were determined from the measured thermal diffusivities, heat capacities and bulk densities over a temperature range of 473 to 1473 K. The thermal conductivities of (Zr 0.58 Pu 0.21 Am 0.21 )N and (Zr 0.80 Pu 0.10 Am 0.10 )N solid solutions were found to be higher than that of (Pu 0.5 Am 0.5 )N due to the high thermal conductivity of ZrN as the principal component, although they were lower than that of ZrN due to the impurifying effect of the transuranium elements. Thus, the thermal conductivities of (Zr x Pu (1-x)/2 Am (1-x)/2) N solid solutions increased with increasing ZrN concentration. Moreover, in order to help to promote the design study of nitride-fueled ADS, the thermal conductivity of the (Zr x Pu (1-x)/2 Am (1-x)/2) N solid solutions were fitted to an equation using the least squares method. (author)

Long-term behavior of refractory thorium-plutonium dioxide solid solutions

Energy Technology Data Exchange (ETDEWEB)

Claparede, Laurent, E-mail: laurent.claparede@umontpellier.fr [ICSM, UMR 5257 CNRS/CEA/Univ. Montpellier/ENSCM, Site de Marcoule, Bât. 426, BP 17171, 30207 Bagnols/Cèze (France); Guigue, Mireille [CEA, Nuclear Energy Division, RadioChemistry & Processes Department, BP 17171, 30207 Bagnols/Cèze (France); Jouan, Gauthier [CEA, Nuclear Energy Division, DTEC Department, BP 17171, 30207 Bagnols/Cèze (France); Nadah, Nassima [CEA, Nuclear Energy Division, RadioChemistry & Processes Department, BP 17171, 30207 Bagnols/Cèze (France); Dacheux, Nicolas [ICSM, UMR 5257 CNRS/CEA/Univ. Montpellier/ENSCM, Site de Marcoule, Bât. 426, BP 17171, 30207 Bagnols/Cèze (France); Moisy, Philippe [CEA, Nuclear Energy Division, RadioChemistry & Processes Department, BP 17171, 30207 Bagnols/Cèze (France)

2017-01-15

The long-term behavior of Th{sub 0.87}Pu{sub 0.13}O{sub 2} was examined in nitric acid concentrations. The normalized dissolution rates after 3380 days, range from (1.4 ± 0.2) × 10{sup −6} g m{sup −2} d{sup −1} in 5 M HNO{sub 3} down to (3.2 ± 0.4) × 10{sup −8} g m{sup −2} d{sup −1} in 10{sup −3} M HNO{sub 3}, which confirms the high chemical durability of this solid solution. The amounts of plutonium measured in solution lead to 0.9% and 2.1% of dissolved solid in 1 M and 5 M HNO{sub 3}, respectively. In such conditions, the time required to reach the full dissolution of the material varies from 430 years (5 M HNO{sub 3}) to 18,000 years (10{sup −3} M HNO{sub 3}). Moreover, the partial order related to the proton activity (n = 0.45 ± 0.03) suggests that the dissolution is mainly driven by surface reactions occurring at the solid/liquid interface. The characterization of the leached samples by SEM shows small microstructural modifications (i.e. detachment of crystallites) and the absence of neoformed phase while from PXRD, the unit cell parameter and crystallite size are not significantly affected. - Highlights: • Leaching tests of Th{sub 0.87}Pu{sub 0.13}O{sub 2} were performed for 9 years in several nitric acid solutions. • The high chemical durability of thorium-plutonium oxide solid solutions was confirmed. • The solubility of plutonium(IV) was not controlled by the precipitation of plutonium tetrahydroxide in these experiments.

Synthesis and characterization of solid solutions in ABCO 4 system

Science.gov (United States)

Novoselov, A.; Zimina, G.; Komissarova, L.; Pajaczkowska, A.

2006-01-01

Formation of continuous solid solutions with a tetragonal structure of K 2NiF 4-type was investigated by direct solid-state synthesis, carbonate precipitations, the freeze-drying method and the Czochralski crystal growth technique. In the systems of SrLaAlO 4-CaLaAlO 4, SrNdAlO 4-CaNdAlO 4, SrPrAlO 4-CaPrAlO 4, SrLaAlO 4-SrLaGaO 4 and SrLaAlO 4-SrLaFeO 4 solid solutions are formed in the whole concentration range (0.0⩽ x⩽1.0) and in the systems of SrLaAlO 4-SrLaMnO 4 and SrLaAlO 4-SrLaCrO 4 in the limited compositional interval of (0.0⩽ x⩽0.20) and (0.0⩽ x⩽0.25), respectively, with composition dependency of lattice constants following Vegard's law.

The complex synthesis and solid state chemistry of ceria-lanthana solid solutions prepared via a hexamethylenetetramine precipitation

International Nuclear Information System (INIS)

Fleming, P.G.; Holmes, J.D.; Otway, D.J.; Morris, M.A.

2011-01-01

Mixed oxide solid solutions are becoming ever more commercially important across a range of applications. However, their synthesis can be problematical. Here, we show that ceria-lanthana solid solutions can be readily prepared via simple precipitation using hexamethylenetetramine. However, the solution chemistry can be complex, which results in the precipitated particles having a complex structure and morphology. Great care must be taken in both the synthesis and characterisation to quantify the complexity of the product. Even very high heat treatments were not able to produce highly homogeneous materials and X-ray diffractions reveals the non-equilibrium form of particles prepared in this way. Unexpected crystal structures are revealed including a new metastable cubic La 2 O 3 phase. - Graphical abstract: The suggested mechanism for the formation of dual fluorite phase particles, where Step 1 corresponds to room temperature aging, Step 2; heating the solution to 90 deg. C, Step 3; cooling of the solution to room temperature, Step 4; calcination to 500 deg. C, Step 5; calcination to 700 deg. C and Step 6; calcination to 1300 deg. C. The terminology of e.g. La 1-x Ce x (OH) 3 is used to indicate the formation of a mixed oxy-hydroxy participate rather than a definitive assignment of stoichiometry. Similarly, La 1-y Ce y O 2 only implies a mixed solid solution. Highlights: → Mol% of prepared Ce-La oxides did not follow that of reactant mol%. → Complex reaction pathway found to be dependent on metal solution concentrations. → At certain concentrations core shell particles were found to form. → A reaction model was produced based on cationic solubility. → Report lanthana solubility higher than previously reported in CeO 2 .

Direct and indirect effects of radiation on polar solid solutions

International Nuclear Information System (INIS)

Ershov, V.G.; Gaponova, I.S.

1982-01-01

Radiation-chemical decomposition of a solute is due to the direct effect of ionizing radiation on it and also to its reaction with radical-ion products of radiolysis of the solution. At low temperature, the movement of the reagents is limited, and thus it is possible to isolate and evaluate the contribution of direct and indirect effects of radiation on the solute. The present paper is devoted to an investigation of the mechanism of formation of radicals from a solute (LiNO 2 ) in a polar solid solution (CH 3 OH) under the effect of γ-radiation

Effect of Dilute Apple Juice and Preferred Fluids vs Electrolyte Maintenance Solution on Treatment Failure Among Children With Mild Gastroenteritis: A Randomized Clinical Trial.

Science.gov (United States)

Freedman, Stephen B; Willan, Andrew R; Boutis, Kathy; Schuh, Suzanne

2016-05-10

Gastroenteritis is a common pediatric illness. Electrolyte maintenance solution is recommended to treat and prevent dehydration. Its advantage in minimally dehydrated children is unproven. To determine if oral hydration with dilute apple juice/preferred fluids is noninferior to electrolyte maintenance solution in children with mild gastroenteritis. Randomized, single-blind noninferiority trial conducted between the months of October and April during the years 2010 to 2015 in a tertiary care pediatric emergency department in Toronto, Ontario, Canada. Study participants were children aged 6 to 60 months with gastroenteritis and minimal dehydration. Participants were randomly assigned to receive color-matched half-strength apple juice/preferred fluids (n=323) or apple-flavored electrolyte maintenance solution (n=324). Oral rehydration therapy followed institutional protocols. After discharge, the half-strength apple juice/preferred fluids group was administered fluids as desired; the electrolyte maintenance solution group replaced losses with electrolyte maintenance solution. The primary outcome was a composite of treatment failure defined by any of the following occurring within 7 days of enrollment: intravenous rehydration, hospitalization, subsequent unscheduled physician encounter, protracted symptoms, crossover, and 3% or more weight loss or significant dehydration at in-person follow-up. Secondary outcomes included intravenous rehydration, hospitalization, and frequency of diarrhea and vomiting. The noninferiority margin was defined as a difference between groups of 7.5% for the primary outcome and was assessed with a 1-sided α=.025. If noninferiority was established, a 1-sided test for superiority was conducted. Among 647 randomized children (mean age, 28.3 months; 331 boys [51.1%]; 441 (68.2%) without evidence of dehydration), 644 (99.5%) completed follow-up. Children who were administered dilute apple juice experienced treatment failure less often than those

Thermodynamics of dilute aqueous solutions of imidazolium based ionic liquids

International Nuclear Information System (INIS)

Singh, Tejwant; Kumar, Arvind

2011-01-01

Research highlights: → The thermodynamic behaviour of aqueous imidazolium ILs has been investigated. → Volumetric and ultrasonic results indicated the hydrophobic hydration of ILs. → Viscometric studies revealed studied ionic liquids as water-structure makers. → Hydration number increased with increase in alkyl chain length of the cation. - Abstract: Experimental measurements of density ρ, speed of sound u, and viscosity η of aqueous solutions of various 1-alkyl-3-methylimidazolium based ionic liquid (IL) solutions have been performed in dilute concentration regime at 298.15 K to get insight into hydration behaviour of ILs. The investigated ILs are based on 1-alkyl-3-methylimidazolium cation, [C n mim] having [BF 4 ] - , [Cl] - , [C 1 OSO 3 ] - , and [C 8 OSO 3 ] - as anions where n = 4 or 8. Several thermodynamic parameters like apparent molar volume φ V , isentropic compressibility β s , and viscosity B-coefficients have been derived from experimental data. Limiting value of apparent molar volume has been discussed in terms of intrinsic molar volume (V int ) molar electrostriction volume (V elec ), molar disordered (V dis ), and cage volume (V cage ). Viscosity B-coefficients have been used to quantify the kosmotropic or chaotropic nature of ILs. Hydration number of ILs obtained using elctrostriction volume, isentropic compressibility, viscosity, and differential scanning calorimetry have been found to be comparative within the experimental error. The hydrophobic hydration has found to play an important role in hydration of ILs as compared to hydration due to hydrogen bonding and electrostriction. Limiting molar properties, hydration numbers, and B-coefficients have been discussed in terms of alkyl chain length of cation or nature of anion.

Characterization of solid-solution interface by potentiometric titration and electrophoretic mobility

International Nuclear Information System (INIS)

Lindecker, C.; Drot, R.; Fourest, B.; Simoni, E.

1999-01-01

The study of nuclear waste storage in deep geological sites involves the understanding of processes which could produce a possible dispersion or retention of radioelements. The dispersion of solid particles in aqueous solution is consequently important to be characterized. In this bi-phased system it is necessary to determine the characteristics of the solid-solution interface. The method used of this study is the techniques of potentiometric titration applied to heterogeneous systems. The material studied were phosphate matrices which were synthesized in the laboratory. The dependence of their surface change upon the nature of the electrolytes was investigated

Determination of infinite dilution activity coefficients using HS-SPME/GC/FID for hydrocarbons in furfural at temperatures of (298.15, 308.15, and 318.15) K

International Nuclear Information System (INIS)

Arantes Furtado, Filipe; Vieira Coelho, Gerson Luiz

2012-01-01

Highlights: ► Two approaches were proposed using SPME on determination of infinite dilution activity coefficients. ► Infinite dilution activity coefficients of nine solutes in solvent furfural at T = (298.15, 308.15, and 318.15) K. ► Fiber–gas partition coefficients of nine solutes on PDMS at T = (298.15, 308.15, and 318.15) K. ► Optical microscopy analysis and statistical tests to measure possible damages on fiber coating. ► Advantages and limitations of methodology proposed were discussed. - Abstract: A new methodology using the headspace solid phase microextraction (HS-SPME) technique has been used to evaluate the infinite dilution activity coefficient (γ 12 ∞ ) of nine hydrocarbons (alkanes, cycloalkanes, and aromatics) in furfural solvent. The main objective of this study was to validate a faster and lower cost methodology expanding the use of HS-SPME to determine infinite dilution activity of solutes in organic solvents. Two approaches were proposed for the determination of γ 12 ∞ in order to use this technique (HS-SPME). In addition, the fiber–gas partition coefficients (K fg ) for each analyte at each of the studied temperatures were determined. The activity and partition coefficients have been reported at temperatures of (298.15, 308.15, and 318.15) K. The data were compared with the literature infinite dilution data determined by other methods such as liquid–gas chromatography (GLC) and gas stripping. Partial molar excess enthalpies of mixing at infinite dilution for each solute have been determined. The fibers were tested before and after each experiment, using statistical methods to ensure that their properties do not change during the experiments. The fibers were also analyzed by optical microscopy to evaluate possible surface damage by comparing them with new fibers. The activity coefficient values correlated well with the data in the literature and showed average deviations less than 10%.

Hydrothermal synthesis of pollucite, analcime and their solid solutions and analysis of their properties

Energy Technology Data Exchange (ETDEWEB)

Jing, Zhenzi, E-mail: zzjing@tongji.edu.cn [Key Laboratory of Advanced Civil Engineering Materials, Ministry of Education, Tongji University, 4800 Cao' an Road, Shanghai 201804 (China); Cai, Kunchuan; Li, Yan; Fan, Junjie; Zhang, Yi; Miao, Jiajun; Chen, Yuqian [Key Laboratory of Advanced Civil Engineering Materials, Ministry of Education, Tongji University, 4800 Cao' an Road, Shanghai 201804 (China); Jin, Fangming [School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China)

2017-05-15

Pollucite, as a perfect long-term potential host for radioactive Cs immobilization, barely exists in pure form naturally but in an isomorphism form between pollucite and analcime due to coexistence of Cs and Na. Pollucite could be hydrothermally synthesized with Cs-polluted soil or clay minerals which contain Cs and Na, and it is necessary to study the properties of the synthesis if Cs and Na contained. Pure pollucite, analcime and their solid solutions were hydrothermally synthesized with chemicals, and it was found that the most formed pollucite analcime solid solutions with Cs/(Cs + Na) ratios of 2/6–5/6 had very similar properties in mineral composition, morphology and size, structural water (Cs cations) and coordination environment to pollucite. This also suggests that even coexistence of Cs and Na in nature, pollucite favors to form due to site preference for Cs over Na, which leads to the property and the structure of the most solid solutions similar to that of pollucite. - Highlights: •Pure pollucite barely exists in nature due to coexistence of Cs and Na. •Pollucite, analcime and their solid solutions could be hydrothermally synthesized. •Most formed solid solutions were found to have similar properties to pollucite. •Even coexistence in nature, pollucite favors to form due to site preference for Cs over Na.

Light refractive index in indium phosphide and InP-containing solid solutions

International Nuclear Information System (INIS)

Yas'kov, A.D.

1983-01-01

Spectral and temperatUre dependences of the InP and Gasub(x)Insub(1-x)P refractive indexes in the range of 0.98-1.3 μm are measured. The obtained in this case and published earlier experimental data on refractive index dispersion of the InP and solid solutions with its participation are generalized within the framework of a simple model approach based on a consecutiVe account of measured parameters of zone structure with the solid solution composition

Recovery of glycols, sugars, and Related Multiple -OH Compounds from Dilute-Aqueous Solution by Regenerable Adsorption onto Activated Carbons

Energy Technology Data Exchange (ETDEWEB)

Chinn, Daniel [Univ. of California, Berkeley, CA (United States)

1999-06-01

The present research explores the use of adsorption onto activated carbons as a means of recover glycerol, glycols, and sugars from dilute-aqueous solution. Our work is focused on understanding the mechanisms of adsorption onto carbons, assessing the degree of adsorption reversibility with precision, and implementing a bench-scale recovery process that results in a higher product concentration and reduction of the energy load for final purification.

Zirconium-cerin solid solutions: thermodynamic model and thermal stability at high temperature; Solutions solides de zirconium dans la cerine: modele thermodynamique et stabilite thermique a haute temperature

Energy Technology Data Exchange (ETDEWEB)

Janvier, C.

1998-04-02

The oxides-gaseous dioxygen equilibria and the textural thermal stability of six zirconium-cerin solutions Ce{sub 1-x}Zr{sub x}O{sub 2} (0solid solutions and the gaseous oxygen by thermal gravimetric analysis at 600 degrees Celsius has shown that these solutions have not a ideal behaviour. A thermodynamic model where the point defects of solutions are included describe them the best. It becomes then possible to know the variations of the concentrations of the point defects in terms of temperature, oxygen pressure and zirconium concentration. A kinetic study (by calcination at 950 degrees Celsius of the solid solutions) of the specific surface area decrease has revealed a minima (0

Reaction enthalpy from the binding of multivalent cations to anionic polyelectrolytes in dilute solutions

Science.gov (United States)

Hansch, Markus; Kaub, Hans Peter; Deck, Sascha; Carl, Nico; Huber, Klaus

2018-03-01

Dilute solutions of sodium poly(styrene sulfonate) (NaPSS) in the presence of Al3+, Ca2+, and Ba2+ were analysed by means of isothermal titration calorimetry (ITC) in order to investigate the heat effect of bond formation between those cations and the anionic SO3- residues of NaPSS. The selection of the cations was guided by the solution behavior of the corresponding PSS salts from a preceding study [M. Hansch et al., J. Chem. Phys. 148(1), 014901 (2018)], where bonds between Ba2+ and anionic PSS showed an increasing solubility with decreasing temperature and Al3+ exhibited the inverse trend. Unlike to Al3+ and Ba2+, Ca2+ is expected to behave as a purely electrostatically interacting bivalent cation and was thus included in the present study. Results from ITC satisfactorily succeeded to explain the temperature-dependent solution behavior of the salts with Al3+ and Ba2+ and confirmed the non-specific behavior of Ca2+. Additional ITC experiments with salts of Ca2+ and Ba2+ and sodium poly(acrylate) complemented the results on PSS by data from a chemically different polyanion. Availability of these joint sets of polyanion-cation combinations not only offers the chance to identify common features and subtle differences in the solution behavior of polyelectrolytes in the presence of multi-valent cations but also points to a new class of responsive materials.

Solid solution strengthening and diffusion in nickel- and cobalt-based superalloys

Energy Technology Data Exchange (ETDEWEB)

Rehman, Hamad ur

2016-07-01

Nickel and cobalt-based superalloys with a γ-γ{sup '} microstructure are known for their excellent creep resistance at high temperatures. Their microstructure is engineered using different alloying elements, that partition either to the fcc γ matrix or to the ordered γ{sup '} phase. In the present work the effect of alloying elements on their segregation behaviour in nickel-based superalloys, diffusion in cobalt-based superalloys and the temperature dependent solid solution strengthening in nickel-based alloys is investigated. The effect of dendritic segregation on the local mechanical properties of individual phases in the as-cast, heat treated and creep deformed state of a nickel-based superalloy is investigated. The local chemical composition is characterized using Electron Probe Micro Analysis and then correlated with the mechanical properties of individual phases using nanoindentation. Furthermore, the temperature dependant solid solution hardening contribution of Ta, W and Re towards fcc nickel is studied. The room temperature hardening is determined by a diffusion couple approach using nanoindentation and energy dispersive X-ray analysis for relating hardness to the chemical composition. The high temperature properties are determined using compression strain rate jump tests. The results show that at lower temperatures, the solute size is prevalent and the elements with the largest size difference with nickel, induce the greatest hardening consistent with a classical solid solution strengthening theory. At higher temperatures, the solutes interact with the dislocations such that the slowest diffusing solute poses maximal resistance to dislocation glide and climb. Lastly, the diffusion of different technically relevant solutes in fcc cobalt is investigated using diffusion couples. The results show that the large atoms diffuse faster in cobalt-based superalloys similar to their nickel-based counterparts.

Solid solution strengthening and diffusion in nickel- and cobalt-based superalloys

International Nuclear Information System (INIS)

Rehman, Hamad ur

2016-01-01

Nickel and cobalt-based superalloys with a γ-γ ' microstructure are known for their excellent creep resistance at high temperatures. Their microstructure is engineered using different alloying elements, that partition either to the fcc γ matrix or to the ordered γ ' phase. In the present work the effect of alloying elements on their segregation behaviour in nickel-based superalloys, diffusion in cobalt-based superalloys and the temperature dependent solid solution strengthening in nickel-based alloys is investigated. The effect of dendritic segregation on the local mechanical properties of individual phases in the as-cast, heat treated and creep deformed state of a nickel-based superalloy is investigated. The local chemical composition is characterized using Electron Probe Micro Analysis and then correlated with the mechanical properties of individual phases using nanoindentation. Furthermore, the temperature dependant solid solution hardening contribution of Ta, W and Re towards fcc nickel is studied. The room temperature hardening is determined by a diffusion couple approach using nanoindentation and energy dispersive X-ray analysis for relating hardness to the chemical composition. The high temperature properties are determined using compression strain rate jump tests. The results show that at lower temperatures, the solute size is prevalent and the elements with the largest size difference with nickel, induce the greatest hardening consistent with a classical solid solution strengthening theory. At higher temperatures, the solutes interact with the dislocations such that the slowest diffusing solute poses maximal resistance to dislocation glide and climb. Lastly, the diffusion of different technically relevant solutes in fcc cobalt is investigated using diffusion couples. The results show that the large atoms diffuse faster in cobalt-based superalloys similar to their nickel-based counterparts.

Determination of micro-quantities of several elements in soil solution by isotope dilution and activation analyses

International Nuclear Information System (INIS)

Cho, C.M.; Axmann, H.

1965-01-01

Determination of small quantities of plant nutrients in the soil solution of flooded rice soils is a difficult problem. The concentrations of Mn, Fe and P, for example, in some soil solutions are so small that no chemical method gives any accurate result. Neutron activation analysis was reported to give a much lower limit of detectability for several elements, while for elements with low-induced activity after neutron irradiation, substoichiometric isotopic dilution analysis was applied. One of the advantages of neutron activation analysis lies in the fact that simultaneous activation of every inducible element in a sample takes place. This gives an opportunity to determine many elements by one sample preparation and irradiation. This, however, is not a simple task since identification of the activated products and their quantitative estimation becomes very difficult. Certain operations of separation must be carried out before activity measurements. Ion-exchange resin columns and chemical separation following the addition of carriers were successfully used for the determination of many elements after neutron irradiation. These procedures, however, cannot be directly applied to the determination of the elements of agronomic interest. A procedure was developed to determine several elements of agronomic interest. Times of irradiation and cooling, quick separation by ion-exchange columns, together with chemical precipitation for β-emitters of relatively long half-lives, were all combined to get the maximum benefit from neutron activation analysis. For Fe, for which no satisfactory neutron activation analysis has yet been developed, a modified substoichiometric double isotope dilution procedure is applied

Studies on Al-Mg solid solutions using electrical resistivity and microhardness measurements

Energy Technology Data Exchange (ETDEWEB)

Gaber, A.; Afify, N.; El-Halawany, S.M.; Mossad, A. [Assiut Univ. (Egypt). Dept. of Physics

1999-08-01

Al-C at% Mg alloys (C = 0.82, 1.84, 3.76, 5.74 and 12.18) have been selected for this study. From the electrical resistivity measurements it is concluded that the resistivity increment of Al-Mg alloys (in a solid solution state) is proportional to the atomic fractional constituents (Mg and Al) as {delta}{rho}{sub all} = 64.66 c(1-c) {mu}{omega} cm. In addition, both the temperature coefficient of resistivity, {alpha}{sub all} and the relaxation time of the free electrons {tau}{sub all} in the alloys diminish with increasing the solute Mg concentration. The increase of the scattering power, {eta}, with increasing C is interpreted to be due to the contribution of electron-impurity scattering. The percentage increase due to electron-impurity scattering per one atomic percent Mg has been determined as 12.99%. The Debye temperature {theta} decreases as the Mg concentration increases. The microhardness results showed that the solid solution hardening obeys the relation {delta}HV{sub s} = 135.5C{sup 0.778} MPa which is comparable to the theory of solid solution hardening for all alloys; {delta}HV{sub s} {approx} C{sup 0.5-0.67} MPa. (orig.)

AW-101 entrained solids - Solubility versus temperature

International Nuclear Information System (INIS)

GJ Lumetta; RC Lettau; GF Piepel

2000-01-01

This report describes the results of a test conducted by Battelle to assess the solubility of the solids entrained in the diluted AW-101 low-activity waste (LAW) sample. BNFL requested Battelle to dilute the AW-1-1 sample using de-ionized water to mimic expected plant operating conditions. BNFL further requested Battelle to assess the solubility of the solids present in the diluted AW-101 sample versus temperature conditions of 30, 40, and 50 C. BNFL requested these tests to assess the composition of the LAW supernatant and solids versus expected plant-operating conditions. The work was conducted according to test plan BNFL-TP-29953-7, Rev. 0, Determination of the Solubility of LAW Entrained Solids. The test went according to plan, with no deviations from the test plan

Solute redistribution in dendritic solidification with diffusion in the solid

Science.gov (United States)

Ganesan, S.; Poirier, D. R.

1989-01-01

An investigation of solute redistribution during dendritic solidification with diffusion in the solid has been performed using numerical techniques. The extent of diffusion is characterized by the instantaneous and average diffusion parameters. These parameters are functions of the diffusion Fourier number, the partition ratio and the fraction solid. Numerical results are presented as an approximate model, which is used to predict the average diffusion parameter and calculate the composition of the interdendritic liquid during solidification.

Uncertainties associated with lacking data for predictions of solid-solution partitioning of metals in soil

International Nuclear Information System (INIS)

Le, T.T. Yen; Hendriks, A. Jan

2014-01-01

Soil properties, i.e., pH and contents of soil organic matter (SOM), dissolved organic carbon (DOC), clay, oxides, and reactive metals, are required inputs to both mechanistic and empirical modeling in assessing metal solid-solution partitioning. Several of these properties are rarely measured in site-specific risk assessment. We compared the uncertainties induced by lacking data on these soil properties in estimating metal soil solution concentrations. The predictions by the Orchestra framework were more sensitive to lacking soil property data than the predictions by the transfer functions. The deviations between soil solution concentrations of Cd, Ni, Zn, Ba, and Co estimated with measured SOM and those estimated with generic SOM by the Orchestra framework were about 10 times larger than the deviations in the predictions by the transfer functions. High uncertainties were induced by lacking data in assessing solid-solution partitioning of oxy-anions like As, Mo, Sb, Se, and V. Deviations associated with lacking data in predicting soil solution concentrations of these metals by the Orchestra framework reached three-to-six orders of magnitude. The solid-solution partitioning of metal cations was strongly influenced by pH and contents of organic matter, oxides, and reactive metals. Deviations of more than two orders of magnitude were frequently observed between the estimates of soil solution concentrations with the generic values of these properties and the estimates based on the measured data. Reliable information on these properties is preferred to be included in the assessment by either the Orchestra framework or transfer functions. - Highlights: • Estimates of metal solid-solution partitioning sensitive to soil property data. • Uncertainty mainly due to lacking reactive metal contents, pH, and organic matter. • Soil solution concentrations of oxy-anions highly influenced by oxide contents. • Clay contents had least effects on solid-solution partitioning

Uncertainties associated with lacking data for predictions of solid-solution partitioning of metals in soil

Energy Technology Data Exchange (ETDEWEB)

Le, T.T. Yen, E-mail: YenLe@science.ru.nl; Hendriks, A. Jan

2014-08-15

Soil properties, i.e., pH and contents of soil organic matter (SOM), dissolved organic carbon (DOC), clay, oxides, and reactive metals, are required inputs to both mechanistic and empirical modeling in assessing metal solid-solution partitioning. Several of these properties are rarely measured in site-specific risk assessment. We compared the uncertainties induced by lacking data on these soil properties in estimating metal soil solution concentrations. The predictions by the Orchestra framework were more sensitive to lacking soil property data than the predictions by the transfer functions. The deviations between soil solution concentrations of Cd, Ni, Zn, Ba, and Co estimated with measured SOM and those estimated with generic SOM by the Orchestra framework were about 10 times larger than the deviations in the predictions by the transfer functions. High uncertainties were induced by lacking data in assessing solid-solution partitioning of oxy-anions like As, Mo, Sb, Se, and V. Deviations associated with lacking data in predicting soil solution concentrations of these metals by the Orchestra framework reached three-to-six orders of magnitude. The solid-solution partitioning of metal cations was strongly influenced by pH and contents of organic matter, oxides, and reactive metals. Deviations of more than two orders of magnitude were frequently observed between the estimates of soil solution concentrations with the generic values of these properties and the estimates based on the measured data. Reliable information on these properties is preferred to be included in the assessment by either the Orchestra framework or transfer functions. - Highlights: • Estimates of metal solid-solution partitioning sensitive to soil property data. • Uncertainty mainly due to lacking reactive metal contents, pH, and organic matter. • Soil solution concentrations of oxy-anions highly influenced by oxide contents. • Clay contents had least effects on solid-solution partitioning

Active Edge Sites Engineering in Nickel Cobalt Selenide Solid Solutions for Highly Efficient Hydrogen Evolution

KAUST Repository

Xia, Chuan

2017-01-06

An effective multifaceted strategy is demonstrated to increase active edge site concentration in NiCoSe solid solutions prepared by in situ selenization process of nickel cobalt precursor. The simultaneous control of surface, phase, and morphology result in as-prepared ternary solid solution with extremely high electrochemically active surface area (C = 197 mF cm), suggesting significant exposure of active sites in this ternary compound. Coupled with metallic-like electrical conductivity and lower free energy for atomic hydrogen adsorption in NiCoSe, identified by temperature-dependent conductivities and density functional theory calculations, the authors have achieved unprecedented fast hydrogen evolution kinetics, approaching that of Pt. Specifically, the NiCoSe solid solutions show a low overpotential of 65 mV at -10 mV cm, with onset potential of mere 18 mV, an impressive small Tafel slope of 35 mV dec, and a large exchange current density of 184 μA cm in acidic electrolyte. Further, it is shown that the as-prepared NiCoSe solid solution not only works very well in acidic electrolyte but also delivers exceptional hydrogen evolution reaction (HER) performance in alkaline media. The outstanding HER performance makes this solid solution a promising candidate for mass hydrogen production.

Thermodynamics of dilute aqueous solutions of imidazolium based ionic liquids

Energy Technology Data Exchange (ETDEWEB)

Singh, Tejwant [Salt and Marine Chemicals Division, Central Salt and Marine Chemicals Research Institute, Council of Scientific and Industrial Research (CSIR), G.B. Marg, Bhavnagar 364002 (India); Kumar, Arvind, E-mail: arvind@csmcri.or [Salt and Marine Chemicals Division, Central Salt and Marine Chemicals Research Institute, Council of Scientific and Industrial Research (CSIR), G.B. Marg, Bhavnagar 364002 (India)

2011-06-15

Research highlights: The thermodynamic behaviour of aqueous imidazolium ILs has been investigated. Volumetric and ultrasonic results indicated the hydrophobic hydration of ILs. Viscometric studies revealed studied ionic liquids as water-structure makers. Hydration number increased with increase in alkyl chain length of the cation. - Abstract: Experimental measurements of density {rho}, speed of sound u, and viscosity {eta} of aqueous solutions of various 1-alkyl-3-methylimidazolium based ionic liquid (IL) solutions have been performed in dilute concentration regime at 298.15 K to get insight into hydration behaviour of ILs. The investigated ILs are based on 1-alkyl-3-methylimidazolium cation, [C{sub n}mim] having [BF{sub 4}]{sup -}, [Cl]{sup -}, [C{sub 1}OSO{sub 3}]{sup -}, and [C{sub 8}OSO{sub 3}]{sup -} as anions where n = 4 or 8. Several thermodynamic parameters like apparent molar volume {phi}{sub V}, isentropic compressibility {beta}{sub s}, and viscosity B-coefficients have been derived from experimental data. Limiting value of apparent molar volume has been discussed in terms of intrinsic molar volume (V{sub int}) molar electrostriction volume (V{sub elec}), molar disordered (V{sub dis}), and cage volume (V{sub cage}). Viscosity B-coefficients have been used to quantify the kosmotropic or chaotropic nature of ILs. Hydration number of ILs obtained using elctrostriction volume, isentropic compressibility, viscosity, and differential scanning calorimetry have been found to be comparative within the experimental error. The hydrophobic hydration has found to play an important role in hydration of ILs as compared to hydration due to hydrogen bonding and electrostriction. Limiting molar properties, hydration numbers, and B-coefficients have been discussed in terms of alkyl chain length of cation or nature of anion.

Face-centered-cubic Nb-Si solid solutions produced by picosecond pulsed laser quenching

International Nuclear Information System (INIS)

Wang, W.K.; Spaepen, F.

1985-01-01

Face-centered-cubic Nb/sub 100-x/Si/sub x/ solid solutions (10 2 . The lattice parameters of these solutions suggest that the solute atoms can be interstitial or substitutional, probably as a result of a change in the quenching conditions

Multiferroic properties in NdFeO3-PbTiO3 solid solutions

Science.gov (United States)

Kumar, Sunil; Pal, Jaswinder; Kaur, Shubhpreet; Agrawal, P.; Singh, Mandeep; Singh, Anupinder

2018-05-01

The x(NdFeO3) - 1-x(PbTiO3) where x = 0.2 solid solution was prepared using solid state reaction route. The X-ray diffraction (XRD) data reveals the single phase formation. The microstructure shows grain growth with lesser porosity. The energy dispersive analysis confirms the presence of elements in stochiometric proportion. The polarization vs. Electric field loop estabilished a ferroelectric type behavior but lossy in nature. This lossy nature may be due to the presence of large leakage current in solid solution. The Magnetization vs. Magnetic field plot exhibits a unsaturated hysteriss loop indicates that the sample is not purely ferromagnetic.

Structure and high-piezoelectricity in lead oxide solid solutions

NARCIS (Netherlands)

Noheda, B.

2002-01-01

A review of the recent advances in the understanding of piezoelectricity in lead oxide solid solutions is presented, giving special attention to the structural aspects. It has now become clear that the very high electromechanical response in these materials is directly related to the existence of

A self-consistent model for thermodynamics of multicomponent solid solutions

International Nuclear Information System (INIS)

Svoboda, J.; Fischer, F.D.

2016-01-01

The self-consistent concept recently published in this journal (108, 27–30, 2015) is extended from a binary to a multicomponent system. This is possible by exploiting the trapping concept as basis for including the interaction of atoms in terms of pairs (e.g. A–A, B–B, C–C…) and couples (e.g. A–B, B–C, …) in a multicomponent system with A as solvent and B, C, … as dilute solutes. The model results in a formulation of Gibbs-energy, which can be minimized. Examples show that the couple and pair formation may influence the equilibrium Gibbs energy markedly.

Dilution and volatilization of groundwater contaminant discharges in streams

DEFF Research Database (Denmark)

Aisopou, Angeliki; Bjerg, Poul Løgstrup; Sonne, Anne Thobo

2015-01-01

measurement. The solution was successfully applied to published field data obtained in a large and a small Danish stream and provided valuable information on the risk posed by the groundwater contaminant plumes. The results provided by the dilution and volatilization model are very different to those obtained......An analytical solution to describe dilution and volatilization of a continuous groundwater contaminant plume into streams is developed for risk assessment. The location of groundwater plume discharge into the stream (discharge through the side versus bottom of the stream) and different...

Solid solution and amorphous phase in Ti–Nb–Ta–Mn systems synthesized by mechanical alloying

Energy Technology Data Exchange (ETDEWEB)

Aguilar, C., E-mail: claudio.aguilar@usm.cl [Departamento de Ingeniería Metalúrgica y Materiales, Universidad Técnica Federico Santa María, Av. España 1680, Valparaíso (Chile); Guzman, P. [Departamento de Ingeniería Metalúrgica y Materiales, Universidad Técnica Federico Santa María, Av. España 1680, Valparaíso (Chile); Lascano, S. [Departamento de Ingeniería Mecánica, Universidad Técnica Federico Santa María, Av. España 1680, Valparaíso (Chile); Parra, C. [Departamento de Física, Universidad Técnica Federico Santa María, Av. España 1680, Valparaíso (Chile); Bejar, L. [Instituto de Investigaciones Metalúrgicas, Universidad Michoacana de San Nicolás de Hidalgo, Ciudad Universitaria, Morelia C.P. 58000, Michoacán (Mexico); Medina, A. [Facultad de Ingeniería Mecánica, Universidad Michoacana de San Nicolás de Hidalgo, Ciudad Universitaria, C.P. 58000, Michoacán (Mexico); Guzman, D. [Departamento de Metalurgia, Universidad de Atacama, Av. España 485, Copiapó (Chile)

2016-06-15

This work discusses the formation of Ti–30Nb–13Ta–xMn (x: 2, 4 and 6 wt%) solid solution by mechanical alloying using a shaker mill. A solid solution was formed after 15 h of milling and an amorphous phase was formed after 30 h of milling, according to X-ray diffraction results. Disappearance of strongest X-ray diffraction peaks of Nb, Ta and Mn indicated the formation of solid solution, while, X-ray diffraction patterns of powders milled for 30 h showed an amorphous hump with crystalline peaks in the angular range of 35–45° in 2θ. TEM image analysis showed the presence of nanocrystalline intermetallic compounds embedded in an amorphous matrix. Mn{sub 2}Ti, MnTi and NbTi{sub 4} intermetallic compounds were detected and revealed crystallites with size ranging from 3 to 20 nm. The Gibbs free energy for the formation of solid solution and amorphous phase of three ternary systems (Ti–Nb–Ta, Ti–Nb–Mn and Ti–Ta–Mn) was calculated using extended Miedema's model. Experimental and thermodynamic data confirmed that solid solution was first formed in the alloy with 6wt% Mn followed by the formation of an amorphous phase as milling time increases. The presence of Mn promoted the formation of amorphous phase because the atomic radius difference between Mn with Ti, Nb and Ta. - Highlights: • Thermodynamics analysis of extension of solid solution of the Ti–Nb–Ta–Mn system. • Formation of amorphous phase and intermetallic compounds were observed. • Nanocrystalline intermetallic compounds were formed with the sizes between 3 and 20 nm.

Existence of a solid solution from brucite to β-Co(OH)2

International Nuclear Information System (INIS)

Giovannelli, F.; Delorme, F.; Autret-Lambert, C.; Seron, A.; Jean-Prost, V.

2012-01-01

Highlights: ► A solid solution exist between Mg(OH) 2 and β-Co(OH) 2 . ► Synthesis has been performed through an easy and fast coprecipitation route. ► No long range-ordering of the cations occurs. -- Abstract: This study shows that between brucite (Mg(OH) 2 ) and β-Co(OH) 2 , all the compositions are possible. The solid solution Mg 1−x Co x (OH) 2 has been synthesized by an easy and fast coprecipitation route and characterized by XRD and TEM. Single phase powders have been obtained. The particles exhibit platelets morphology with a size close to one hundred nanometers. XRD analysis shows an evolution of the cell parameters when x increases and demonstrates that no ordering of the cations occurs. However, extra reflections on TEM electron diffraction patterns seem to indicate that local ordering can exist. The compounds issued from this solid solution could be good candidates as precursors in order to obtain Mg–Co mixed oxide with all possible cationic ratios.

Calorimetric measurements on plutonium rich (U,Pu)O2 solid solutions

International Nuclear Information System (INIS)

Kandan, R.; Babu, R.; Nagarajan, K.; Vasudeva Rao, P.R.

2008-01-01

Enthalpy increments of U (1-y) Pu y O 2 solid solutions with y = 0.45, 0.55 and 0.65 were measured using a high-temperature differential calorimeter by employing the method of inverse drop calorimetry in the temperature range 956-1803 K. From the fit equations for the enthalpy increments, other thermodynamic functions such as heat capacity, entropy and Gibbs energy function have been computed in the temperature range 298-1800 K. The results are presented and compared with the data available in the literature. The results indicate that the enthalpies of U (1-y) Pu y O 2 solid solutions with y = 0.45, 0.55 and 0.65 obey the Neumann-Kopp's molar additivity rule

A new tool for an old job: Using fixed cell scanning calorimetry to investigate dilute aqueous solutions

International Nuclear Information System (INIS)

Woolley, E.M.

2007-01-01

The development of fixed twin cell temperature scanning calorimeters has enabled the more efficient determination of heat capacities of dilute aqueous solutions with a precision comparable to that of the Picker flow heat capacity calorimeters developed nearly 40 years ago. Experiments require less than 0.5 cm 3 of solution, and results can be obtained routinely over the temperature range (278 to 395) K at pressures up to a few bars. Multiple scanning of samples by both increasing and decreasing temperature allows assessment of instrument drift, solute stability, and reproducibility of results. Chemical calibration is essential to take full advantage of the precision and sensitivity of the calorimeters. The calorimetric output is a direct measure of the difference in heat capacity per unit volume of a solution and of a reference liquid, usually water. Thus, densities of the solution and reference liquid are needed to transform the results into heat capacities per unit mass of solution. Examples of solutes that have been investigated include a variety of inorganic and organic compounds that dissolve to give simple ionic or neutral species, or that produce complexes or species that exist in equilibrium distributions that can change as the temperature is scanned. Appropriate selection of the results from experiments on combinations of solutes allows calculation of standard state (zero concentration) thermodynamic quantities for chemical processes and reactions over the ranges of temperature scanned at the solution compositions investigated. Results for a few specific systems are presented and discussed for some representative classes of solutes that have been investigated in our laboratory since 1998

Visualizing phase transition behavior of dilute stimuli responsive polymer solutions via Mueller matrix polarimetry.

Science.gov (United States)

Narayanan, Amal; Chandel, Shubham; Ghosh, Nirmalya; De, Priyadarsi

2015-09-15

Probing volume phase transition behavior of superdiluted polymer solutions both micro- and macroscopically still persists as an outstanding challenge. In this regard, we have explored 4 × 4 spectral Mueller matrix measurement and its inverse analysis for excavating the microarchitectural facts about stimuli responsiveness of "smart" polymers. Phase separation behavior of thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) and pH responsive poly(N,N-(dimethylamino)ethyl methacrylate) (PDMAEMA) and their copolymers were analyzed in terms of Mueller matrix derived polarization parameters, namely, depolarization (Δ), diattenuation (d), and linear retardance (δ). The Δ, d, and δ parameters provided useful information on both macro- and microstructural alterations during the phase separation. Additionally, the two step action ((i) breakage of polymer-water hydrogen bonding and (ii) polymer-polymer aggregation) at the molecular microenvironment during the cloud point generation was successfully probed via these parameters. It is demonstrated that, in comparison to the present techniques available for assessing the hydrophobic-hydrophilic switch over of simple stimuli-responsive polymers, Mueller matrix polarimetry offers an important advantage requiring a few hundred times dilute polymer solution (0.01 mg/mL, 1.1-1.4 μM) at a low-volume format.

Effect of Aging Temperature on Corrosion Behavior of Sintered 17-4 PH Stainless Steel in Dilute Sulfuric Acid Solution

Science.gov (United States)

Szewczyk-Nykiel, Aneta; Kazior, Jan

2017-07-01

The general corrosion behavior of sintered 17-4 PH stainless steel processed under different processing conditions in dilute sulfuric acid solution at 25 °C was studied by open-circuit potential measurement and potentiodynamic polarization technique. The corrosion resistance was evaluated based on electrochemical parameters, such as polarization resistance, corrosion potential, corrosion current density as well as corrosion rate. The results showed that the precipitation-hardening treatment could significantly improve the corrosion resistance of the sintered 17-4 PH stainless steel in studied environment. As far as the influence of aging temperature on corrosion behavior of the sintered 17-4 PH stainless steel is concerned, polarization resistance and corrosion rate are reduced with increasing aging temperature from 480 up to 500 °C regardless of the temperature of solution treatment. It can be concluded that the highest corrosion resistance in 0.5 M H2SO4 solution exhibits 17-4 PH after solution treatment at 1040 °C followed by aging at 480 °C.

Enthalpies of dilution of aqueous Li{sub 2}B{sub 4}O{sub 7} solutions at 298.15K and application of ion-interaction model

Energy Technology Data Exchange (ETDEWEB)

Yin Guoyin [Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008 (China); Graduate School of Chinese Academy of Sciences, Beijing 100039 (China); Yao Yan [Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008 (China) and Graduate School of Chinese Academy of Sciences, Beijing 100039 (China)]. E-mail: yaoy@isl.ac.cn; Jiao Baojuan [Department of Chemistry, Northwest University, Xi' an 710069 (China); Chen Sanping [Department of Chemistry, Northwest University, Xi' an 710069 (China); Gao Shengli [Department of Chemistry, Northwest University, Xi' an 710069 (China)

2005-09-15

The enthalpies of dilution have been measured for aqueous Li{sub 2}B{sub 4}O{sub 7} solutions from 0.0212 to 2.1530molkg{sup -1} at 298.15K. The relative apparent molar enthalpies, L{sub {phi}}, and relative partial molar enthalpies of the solvent and solute, L-bar{sub 1} and L-bar{sub 2} were calculated. The thermodynamic properties of the complex aqueous solutions were represented with a modified Pitzer ion-interaction model.

Thermal expansion of TRU nitride solid solutions as fuel materials for transmutation of minor actinides

International Nuclear Information System (INIS)

Takano, Masahide; Akabori, Mitsuo; Arai, Yasuo; Minato, Kazuo

2009-01-01

The lattice thermal expansion of the transuranium nitride solid solutions was measured to investigate the composition dependence. The single-phase solid solution samples of (Np 0.55 Am 0.45 )N, (Pu 0.59 Am 0.41 )N, (Np 0.21 Pu 0.52 Am 0.22 Cm 0.05 )N and (Pu 0.21 Am 0.18 Zr 0.61 )N were prepared by carbothermic nitridation of the respective transuranium dioxides and nitridation of Zr metal through hydride. The lattice parameters were measured by the high temperature X-ray diffraction method from room temperature up to 1478 K. The linear thermal expansion of each sample was determined as a function of temperature. The average thermal expansion coefficients over the temperature range of 293-1273 K for the solid solution samples were 10.1, 11.5, 10.8 and 8.8 x 10 -6 K -1 , respectively. Comparison of these values with those for the constituent nitrides showed that the average thermal expansion coefficients of the solid solution samples could be approximated by the linear mixture rule within the error of 2-3%.

Impact of dilution on the microstructure and properties of Ni-based 625 alloy coatings

Directory of Open Access Journals (Sweden)

Tiago Jose Antoszczyszyn

2014-06-01

Full Text Available Nickel-based alloy IN 625 is used to protect components of aircrafts, power generation and oil refinery due to an association of toughness and high corrosion resistance. These properties are associated with the chemical composition and microstructure of coatings which depend on the processing parameters and the composition of the component being protected. This paper assessed impact of dilution on the microstructure and properties of the Ni alloy IN 625 deposited by Plasma Transferred Arc (PTA on two substrates: carbon steel API 5L and stainless steel AISI 316L. Differences due to the interaction with the substrate were maximized analyzing single layer coatings, processed with three deposition current: 120, 150 and 180 A. Correlation with a cast Nickel-based alloy sample contributed to assess the impact of dilution on coatings. Dilution was determined by the area ratio and Vickers hardness measured on the transverse section of coatings. Scanning electron and Laser confocal microscopy and X-ray diffraction analysis were carried out to characterize the microstructure. Results indicated the increasing dilution with the deposition current was deeply influenced by the substrate. Dilution ranging from 5 to 29% was measured on coatings processed on the API 5L steel and from 22 to 51% on the low thermal conductivity AISI 316L steel substrate. Differences on the microstructure and properties of coatings can be associated with the interaction with each substrate. Higher fraction of carbides account for the higher coating hardness when processing on API 5L whereas the low thermal conductivity of AISI 316L and the higher Fe content in solid solution contributed to the lower hardness of coatings.

Kinetics of a new phase formation in supersaturated solid solutions. 1. Dilute one-component systems

International Nuclear Information System (INIS)

Dubinko, V.I.

1991-07-01

A complete set of kinetic equations describing the diffusion decay of supersaturated solutions, as well as the formation of new-phase fluctuations in equilibrium systems, is derived. A novel method of determining forward and backward reaction rates entering the master equation is proposed which does not require the use of any reference cluster size distribution, either the constrained or the true equilibrium one, employed in all modifications of the classical nucleation theory. Instead, this reference distribution can be obtained as an equilibrium solution of the present master equation. The main advantage of this method is the possibility to take into account various factors affecting the diffusion decay, such as the reaction kinetics at the precipitate surfaces and the diffusion kinetics in the mother phase with account of elastic interaction between nucleating species and their clusters. The latter is of a key importance in the irradiation environment considered in the forthcoming second part of the article. (author). 3 refs

A fluorescent chemosensor for Zn(II). Exciplex formation in solution and the solid state.

Science.gov (United States)

Bencini, Andrea; Berni, Emanuela; Bianchi, Antonio; Fornasari, Patrizia; Giorgi, Claudia; Lima, Joao C; Lodeiro, Carlos; Melo, Maria J; de Melo, J Seixas; Parola, Antonio Jorge; Pina, Fernando; Pina, Joao; Valtancoli, Barbara

2004-07-21

The macrocyclic phenanthrolinophane 2,9-[2,5,8-triaza-5-(N-anthracene-9-methylamino)ethyl]-[9]-1,10-phenanthrolinophane (L) bearing a pendant arm containing a coordinating amine and an anthracene group forms stable complexes with Zn(II), Cd(II) and Hg(II) in solution. Stability constants of these complexes were determined in 0.10 mol dm(-3) NMe(4)Cl H(2)O-MeCN (1:1, v/v) solution at 298.1 +/- 0.1 K by means of potentiometric (pH metric) titration. The fluorescence emission properties of these complexes were studied in this solvent. For the Zn(II) complex, steady-state and time-resolved fluorescence studies were performed in ethanol solution and in the solid state. In solution, intramolecular pi-stacking interaction between phenanthroline and anthracene in the ground state and exciplex emission in the excited state were observed. From the temperature dependence of the photostationary ratio (I(Exc)/I(M)), the activation energy for the exciplex formation (E(a)) and the binding energy of the exciplex (-DeltaH) were determined. The crystal structure of the [ZnLBr](ClO(4)).H(2)O compound was resolved, showing that in the solid state both intra- and inter-molecular pi-stacking interactions are present. Such interactions were also evidenced by UV-vis absorption and emission spectra in the solid state. The absorption spectrum of a thin film of the solid complex is red-shifted compared with the solution spectra, whereas its emission spectrum reveals the unique featureless exciplex band, blue shifted compared with the solution. In conjunction with X-ray data the solid-state data was interpreted as being due to a new exciplex where no pi-stacking (full overlap of the pi-electron cloud of the two chromophores - anthracene and phenanthroline) is observed. L is a fluorescent chemosensor able to signal Zn(II) in presence of Cd(II) and Hg(II), since the last two metal ions do not give rise either to the formation of pi-stacking complexes or to exciplex emission in solution.

Further development of IDGS: Isotope dilution gamma-ray spectrometry

International Nuclear Information System (INIS)

Li, T.K.; Parker, J.L.; Kuno, Y.; Sato, S.; Kamata, M.; Akiyama, T.

1991-01-01

The isotope dilution gamma-ray spectrometry (IDGS) technique for determining the plutonium concentration and isotopic composition of highly radioactive spent-fuel dissolver solutions has been further developed. Both the sample preparation and the analysis have been improved. The plutonium isotopic analysis is based on high-resolution, low-energy gamma-ray spectrometry. The plutonium concentration in the dissolver solutions then is calculated from the measured isotopic differences among the spike, the dissolver solution, and the spiked dissolver solution. Plutonium concentrations and isotopic compositions of dissolver solutions analyzed from this study agree well with those obtained by traditional isotope dilution mass spectrometry (IDMS) and are consistent with the first IDGS experimental result. With the current detector efficiency, sample size, and a 100-min count time, the estimated precision is ∼0.5% for 239 Pu and 240 Pu isotopic analyses and ∼1% for the plutonium concentration analysis. 5 refs., 2 figs., 7 tabs

Critical mass variation of 239Pu with water dilution

International Nuclear Information System (INIS)

Pearlstein, S.

1996-01-01

The critical mass of an unreflected solid sphere of 239 Pu is ∼ 10 kg. The increase in critical mass observed for small water dilutions of unreflected 239 Pu spheres is paradoxical. Introducing small amounts of water uniformly throughout the sphere increases the spherical volume containing the same amount of 239 Pu as the critical solid sphere. The increase in radius decreases the surface-to-volume ratio of the sphere, which has the effect to first order of decreasing the neutron leakage, which is proportional to the surface, relative to the fissions, which are proportional to the volume. The reduction in neutron leakage is expected to reduce the critical mass, but instead, the critical mass is observed to increase. It is discussed how changes in the fast neutron spectrum with corresponding changes in the nuclear parameters result in an increase in critical mass for small water dilutions

Dynamic Aspects of Solid Solution Cathodes for Electrochemical Power Sources

DEFF Research Database (Denmark)

Atlung, Sven; West, Keld; Jacobsen, Torben

1979-01-01

Battery systems based on alkali metal anodes and solid solution cathodes,i.e., cathodes based on the insertion of the alkali cation in a "host lattice,"show considerable promise for high energy density storage batteries. Thispaper discusses the interaction between battery requirements...

Optimisation of Dilute Sulphuric Acid Hydrolysis of Waste ...

African Journals Online (AJOL)

Dilute sulphuric acid hydrolysis of waste paper was investigated in this study. The effects of acid concentration, time, temperature and liquid to solid ratio on the total reducing sugar concentration were studied over three levels using a four variable Box-Behnken design (BBD). A statistical model was developed for the ...

High-temperature, Knudsen cell-mass spectroscopic studies on lanthanum oxide/uranium dioxide solid solutions

International Nuclear Information System (INIS)

Sunder, S.; McEachern, R.; LeBlanc, J.C.

2001-01-01

Knudsen cell-mass spectroscopic experiments were carried out with lanthanum oxide/uranium oxide solid solutions (1%, 2% and 5% (metal at.% basis)) to assess the volatilization characteristics of rare earths present in irradiated nuclear fuel. The oxidation state of each sample used was conditioned to the 'uranium dioxide stage' by heating in the Knudsen cell under an atmosphere of 10% CO 2 in CO. The mass spectra were analyzed to obtain the vapour pressures of the lanthanum and uranium species. It was found that the vapour pressure of lanthanum oxide follows Henry's law, i.e., its value is directly proportional to its concentration in the solid phase. Also, the vapour pressure of lanthanum oxide over the solid solution, after correction for its concentration in the solid phase, is similar to that of uranium dioxide. (authors)

Quantification of 13 priority polycyclic aromatic hydrocarbons in human urine by headspace solid-phase microextraction gas chromatography-isotope dilution mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Campo, Laura [Department of Occupational and Environmental Health, University of Milan and Fondazione IRCCS Ospedale Maggiore Policlinico, Mangiagalli e Regina Elena, Milan (Italy)], E-mail: laura.campo@unimi.it; Mercadante, Rosa; Rossella, Federica; Fustinoni, Silvia [Department of Occupational and Environmental Health, University of Milan and Fondazione IRCCS Ospedale Maggiore Policlinico, Mangiagalli e Regina Elena, Milan (Italy)

2009-01-12

Polycyclic aromatic hydrocarbons (PAHs) are common environmental pollutants in both living and working environments. The aim of this study was the development of a headspace solid-phase microextraction gas chromatography-isotope dilution mass spectrometry (HS-SPME/GC-IDMS) method for the simultaneous quantification of 13 PAHs in urine samples. Different parameters affecting PAHs extraction by HS-SPME were considered and optimized: type/thickness of fiber coatings, extraction temperature/time, desorption temperature/time, ionic strength and sample agitation. The stability of spiked PAHs solutions and of real urine samples stored up to 90 days in containers of different materials was evaluated. In the optimized method, analytes were absorbed for 60 min at 80 deg. C in the sample headspace with a 100 {mu}m polydimethylsiloxane fiber. The method is very specific, with linear range from the limit of quantification to 8.67 x 10{sup 3} ng L{sup -1}, a within-run precision of <20% and a between-run precision of <20% for 2-, 3- and 4-ring compounds and of <30% for 5-ring compounds, trueness within 20% of the spiked concentration, and limit of quantification in the 2.28-2.28 x 10{sup 1} ng L{sup -1} range. An application of the proposed method using 15 urine samples from subjects exposed to PAHs at different environmental levels is shown.

Vaporization study on vanadium-oxygen solid solution by mass spectrometric method

International Nuclear Information System (INIS)

Banchorndhevakul, W.; Matsui, Tsuneo; Naito, Keiji

1986-01-01

The vapor pressures over vanadium-oxygen solid solution (0.001 ≤ O/V ≤ 0.145) were measured by mass-spectrometric method in the temperature range of 1,855 ∼ 2,117 K. The main vapor species were observed to be V(g) and VO(g). The vapor pressure of V(g) is higher than that of VO(g) over the solid solutions with all O/V ratios except for O/V = 0.145. The vapor pressure of V(g) is nearly independent of O/V ratio. The vapor pressure of VO(g) decreases with decreasing O/V ratio. The oxygen partial pressure was calculated as a function of temperature and O/V ratio from the vapor pressures of V(g) and VO(g), from which the partial molar enthalpy and entropy of oxygen in the solid solution were determined. The partial molar enthalpy of oxygen was observed to be independent of composition, suggesting the presence of very weak interaction between interstitial oxygens. The compositional dependence of the partial molar entropy of oxygen can be explained by assuming the occupation of the octahedral site in bcc vanadium lattice by the interstitial oxygens. The excess partial molar entropy of oxygen was compared with the value derived from the sum of the contributions from the volume expansion, electronic heat capacity and vibrational terms. (author)

Studies on thermal expansion and XPS of urania-thoria solid solutions

International Nuclear Information System (INIS)

Anthonysamy, S.; Panneerselvam, G.; Bera, Santanu; Narasimhan, S.V.; Vasudeva Rao, P.R.

2000-01-01

The thermal expansion characteristics of polycrystalline (U y Th 1-y )O 2 solid solutions with y=0.13, 0.55 and 0.91 were determined in the temperature range from 298 to 1973 K by means of X-ray diffraction technique. For these temperatures, the average linear thermal expansion coefficients for (U 0.13 Th 0.87 )O 2 , (U 0.55 Th 0.45 )O 2 and (U 0.91 Th 0.09 )O 2 are 1.033x10 -5 , 1.083x10 -5 and 1.145x10 -5 K -1 , respectively. The measured thermal expansion values were compared with those calculated by applying the equations for linear thermal expansion of pure urania and thoria. It was shown that the stoichiometric (U, Th)O 2 solid solutions are almost ideal at least up to 2000 K. The binding energies of U 4f 7/2 and Th 4f 7/2 electrons of (U 0.1 Th 0.9 )O 2 , (U 0.25 Th 0.75 )O 2 , (U 0.50 Th 0.50 )O 2 , (U 0.75 Th 0.25 )O 2 and (U 0.90 Th 0.10 )O 2 were experimentally determined by X-ray photoelectron spectroscopy. The result showed the presence of only U 4+ and Th 4+ chemical states in the stoichiometric urania-thoria solid solutions

High-temperature x-ray diffraction study of HfTiO4-HfO2 solid solutions

International Nuclear Information System (INIS)

Carpenter, D.A.

1975-01-01

High-temperature x-ray diffraction techniques were used to determine the axial thermal expansion curves of HfTiO 4 -HfO 2 solid solutions as a function of composition. Data show increasing anisotropy with increasing HfO 2 content. An orthorhombic-to-monoclinic phase transformation was detected near room temperature for compositions near the high HfO 2 end of the orthorhombic phase field and for compositions within the two-phase region (HfTiO 4 solid solution plus HfO 2 solid solution). An orthorhombic-to-cubic phase transformation is indicated by data from oxygen-deficient materials at greater than 1873 0 K. (U.S.)

Enzymatic saccharification of dilute acid pretreated saline crops for fermentable sugar production

Energy Technology Data Exchange (ETDEWEB)

Zheng, Yi; Zhang, Ruihong [Biological and Agricultural Engineering Department, University of California, Davis One Shields Avenue, Davis, CA 95616 (United States); Pan, Zhongli [Biological and Agricultural Engineering Department, University of California, Davis One Shields Avenue, Davis, CA 95616 (United States); Processed Foods Research Unit, USDA-ARS-WRRC, 800 Buchanan Street, Albany, CA 94710 (United States); Wang, Donghai [Biological and Agricultural Engineering Department, Kansas State University, Manhattan, KS 66506 (United States)

2009-11-15

Four saline crops [athel (Tamarix aphylla L), eucalyptus (Eucalyptus camaldulensis), Jose Tall Wheatgrass (Agropyron elongatum), and Creeping Wild Ryegrass (Leymus triticoides)] that are used in farms for salt uptake from soil and drainage irrigation water have the potential for fuel ethanol production because they don't take a large number of arable lands. Dilute sulfuric acid pretreatment and enzymatic hydrolysis were conducted to select the optimum pretreatment conditions and the best saline crop for further enzymatic hydrolysis research. The optimum dilute acid pretreatment conditions included T = 165 C, t = 8 min, and sulfuric acid concentration 1.4% (w/w). Creeping Wild Ryegrass was decided to be the best saline crop. Solid loading, cellulase and {beta}-glucosidase concentrations had significant effects on the enzymatic hydrolysis of dilute acid pretreated Creeping Wild Ryegrass. Glucose concentration increased by 36 mg/mL and enzymatic digestibility decreased by 20% when the solid loading increased from 4 to 12%. With 8% solid loading, enzymatic digestibility increased by over 30% with the increase of cellulase concentration from 5 to 15 FPU/g-cellulose. Under given cellulase concentration of 15 FPU/g-cellulose, 60% increase of enzymatic digestibility of pretreated Creeping Wild Ryegrass was obtained with the increase of {beta}-glucosidase concentration up to 15 CBU/g-cellulose. With a high solid loading of 10%, fed-batch operation generated 12% and 18% higher enzymatic digestibility and glucose concentration, respectively, than batch process. (author)

The effects of additives on the microstructure and sinterability of molybdenum oxide - study of related solid solutions

International Nuclear Information System (INIS)

Kassem, M.

2006-01-01

This study focuses on the phase transformation induced during mixing a fixed quantity of MoO 3 with various concentration of V 2 O 5 , Bn 2 O 5 , Al 2 O 3 and pure aluminium. These concentrations are 2, 3, 4, 5, 10, 20, 40 and 50%. Employing several physical techniques such as x-ray powder diffraction, FTIR and DTA, different solid solution were identified. Also the compressibility and sintering of these solid solutions have been studied via the variation of the density of pellets prepared from these solid solutions (Author)

Activity coefficients at infinite dilution and enthalpies of solution of methanol, 1-butanol, and 1-hexanol in 1-hexyl-3-methyl-imidazolium bis(trifluoromethyl-sulfonyl) imide

International Nuclear Information System (INIS)

Heintz, Andreas; Verevkin, Sergey P.; Lehmann, Jochen K.; Vasiltsova, Tatiana V.; Ondo, Daniel

2007-01-01

Activity coefficients at infinite dilution γ i ∼ of methanol, 1-butanol, and 1-hexanol in the ionic liquid 1-hexyl-3-methyl-imidazolium bis(trifluoromethyl-sulfonyl) imide ([HMIM][NTf 2 ]) have been determined by gas chromatography using the ionic liquids as stationary phase. The measurements were carried out at different temperatures between 298K and 396K. From the temperature dependence of the limiting activity coefficients partial molar excess enthalpies at infinite dilution H i E,∼ of the alcohol in the ionic liquid have been derived. Additionally, enthalpies of solution of the same alcohols in the [HMIM][NTf 2 ] have been measured at T=298.15K in the range of low concentrations using titration calorimetry. Results at infinite dilution, H i E,∼ , are compared with those indirectly obtained from activity coefficients in infinite dilution γ i ∼ . Within the experimental error of both methods thermodynamic consistency has been confirmed

Existence of a solid solution from brucite to {beta}-Co(OH){sub 2}

Energy Technology Data Exchange (ETDEWEB)

Giovannelli, F., E-mail: fabien.giovannelli@univ-tours.fr [LEMA, UMR 6157 CNRS - CEA, Universite Francois Rabelais, 15 rue de la chocolaterie, 41000 Blois (France); Delorme, F.; Autret-Lambert, C. [LEMA, UMR 6157 CNRS - CEA, Universite Francois Rabelais, 15 rue de la chocolaterie, 41000 Blois (France); Seron, A.; Jean-Prost, V. [BRGM, 3 Avenue Claude Guillemin, BP 36009, 45060 Orleans Cedex 2 (France)

2012-05-15

Highlights: Black-Right-Pointing-Pointer A solid solution exist between Mg(OH){sub 2} and {beta}-Co(OH){sub 2}. Black-Right-Pointing-Pointer Synthesis has been performed through an easy and fast coprecipitation route. Black-Right-Pointing-Pointer No long range-ordering of the cations occurs. -- Abstract: This study shows that between brucite (Mg(OH){sub 2}) and {beta}-Co(OH){sub 2}, all the compositions are possible. The solid solution Mg{sub 1-x}Co{sub x}(OH){sub 2} has been synthesized by an easy and fast coprecipitation route and characterized by XRD and TEM. Single phase powders have been obtained. The particles exhibit platelets morphology with a size close to one hundred nanometers. XRD analysis shows an evolution of the cell parameters when x increases and demonstrates that no ordering of the cations occurs. However, extra reflections on TEM electron diffraction patterns seem to indicate that local ordering can exist. The compounds issued from this solid solution could be good candidates as precursors in order to obtain Mg-Co mixed oxide with all possible cationic ratios.

GRAIN-BOUNDARY PRECIPITATION UNDER IRRADIATION IN DILUTE BINARY ALLOYS

Institute of Scientific and Technical Information of China (English)

S.H. Song; Z.X. Yuan; J. Liu; R.G.Faulkner

2003-01-01

Irradiation-induced grain boundary segregation of solute atoms frequently bring about grain boundary precipitation of a second phase because of its making the solubility limit of the solute surpassed at grain boundaries. Until now the kinetic models for irradiation-induced grain boundary precipitation have been sparse. For this reason, we have theoretically treated grain boundary precipitation under irradiation in dilute binary alloys. Predictions ofγ'-Ni3Si precipitation at grain boundaries ave made for a dilute Ni-Si alloy subjected to irradiation. It is demonstrated that grain boundary silicon segregation under irradiation may lead to grain boundaryγ'-Ni3 Si precipitation over a certain temperature range.

Influence of solid loading on D-xylose production through dilute sulphuric acid hydrolysis of olive stones

Directory of Open Access Journals (Sweden)

Cuevas, M.

2015-09-01

Full Text Available The selective hydrolysis of hemicellulose from olive stones was attempted in order to achieve a maximum D-xylose yield. For this aim, batch hydrolysis was conducted under different operating conditions of temperature, acid concentration and solid loading. Firstly, distilled water, sulphuric acid and nitric acid were assessed as hydrolytic agents at different temperatures (200, 205, 210 and 220 °C and at a fixed acid concentration (0.025 M. Sulphuric acid and 200 °C were selected for the subsequent dilute acid hydrolysis optimization based on the obtained D-xylose yields. The combined influence of solid loading (from 29.3 to 170.7 g olive stones into 300 mL acid solution and sulphuric acid concentration (0.006–0.034 M on the release of D-xylose was then estimated by response surface methodology. According to a statistical analysis, both parameters had significant interaction effects on D-xylose production. The results illustrated that the higher the solid loading, the higher the required acid concentration. The decrease in the solid/liquid ratio in the reactor had a positive effect on D-xylose extraction and on the amount of acid used. The optimum solid loading and sulphuric acid concentration were determined to be 50 g (solid/liquid ratio 1/6 and 0.016 M, respectively. Under these conditions, the predicted D-xylose yield (expressed as g of sugar per 100 g of dry matter fed was 20.4 (87.2% of maximum attainable.Se ha desarrollado una hidrólisis selectiva de la fracción hemicelulósica del hueso de aceituna con el fin de obtener el máximo rendimiento de D-xilosa. Para ello las hidrólisis se llevaron a cabo en un reactor discontinuo a distintas condiciones de temperatura, concentración de ácido y carga de sólidos. En primer lugar se evaluó la capacidad hidrolítica del agua destilada y de los ácidos nítrico y sulfúrico a distintas temperaturas (200, 205, 210 y 220°C manteniendo fija la concentración de ácido (0,025 M. A partir de

Ionic thermocurrents and ionic conductivity of solid solutions of SrF2 and YbF3

NARCIS (Netherlands)

Meuldijk, J.; Hartog, den H.W.

1983-01-01

We report dielectric [ionic thermocurrent (!TC)] experiments and ionic conductivity of cubic solid solutions of the type Sr1-xYbxF2+x. These combined experiments provide us with new information concerning the ionic conductivity mechanisms which play an important role in solid solutions Sr1-xRxF2+x

Studying the Super-cooled Solid Solution Breakdown of V-1341 Aluminum Alloy

Directory of Open Access Journals (Sweden)

Yu. A. Puchkov

2017-01-01

Full Text Available Deformable alloys of the Al-Mg-Si system are widely used in aviation industry, rocket engineering, shipbuilding, as well as on railway and highway transport. These alloys are characterized by high stamping ability, weld-ability, and machinability with a comparatively high strength and corrosion resistance in a heat-strengthened state. A promising alloy of the Al-Mg-Si system with increased structural strength and manufacturability is on par with foreign analogues in properties is the V-1341 alloy [1, 2].The properties of heat-treatable aluminum alloys strongly depend on the cooling rate of the product during quenching [3-12], which determines the structure and level of residual stresses. Decrease in structural strength, tendency to pitting and inter-crystalline corrosion with slow cooling from the quenching temperature is caused by formation of coarse unequiaxed precipitate, precipitates-free zones, and also by decreasing proportion of inclusions of the strengthening phase [3-12].Thus, the relevant task is to study the effect of isothermal quenching modes on the structure of deformable V-1341 aluminum alloy thermally hardened.The paper studies the impact of isothermal time in quenching on the composition and morphology of breakdown products of the V-1341 alloy solid solution. It is shown that at isothermal time under the solid solution breakdown, at first on the dispersoid surface and then in the solid solution are formed and grow large needle-like crystals of the β'-phase which are structural concentrators of stresses. An increasing isothermal time leads to decreasing solid solution super-saturation by doping elements and vacancies. This leads to a decrease in the fraction of the coherent finely dispersed hardening β '' phase, and also to an increase in the width of the precipitates-free zone.

Activity coefficients at infinite dilution and physicochemical properties for organic solutes and water in the ionic liquid 1-(3-hydroxypropyl)pyridinium bis(trifluoromethylsulfonyl)-amide

International Nuclear Information System (INIS)

Marciniak, Andrzej

2011-01-01

Highlights: → The γ 13 ∞ and KL for 46 solutes in the ionic liquid [N-C3OHPY][NTf2] were determined by GLC at different temperatures. → The partial molar excess Gibbs energies ΔG 1 E,∞ , enthalpies ΔH 1 E,∞ and entropies ΔS 1 E,∞ at infinite dilution were calculated. → The selectivities for aliphatics/aromatics hydrocarbons separation problem were calculated and compared to other ILs, NMP and sulfolane. → The selectivities for selected compounds which form azeotropic mixtures were calculated. - Abstract: The activity coefficients at infinite dilution, γ 13 ∞ and gas-liquid partition coefficients, K L for 46 solutes: alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, alcohols, thiophene, ethers, ketones, acetic acid, and water in the ionic liquid 1-(3-hydroxypropyl)pyridinium bis(trifluoromethylsulfonyl)-amide were determined by gas-liquid chromatography at the temperatures from (308.15 to 378.15) K. The partial molar excess Gibbs free energies ΔG 1 E,∞ , enthalpies ΔH 1 E,∞ and entropies ΔS 1 E,∞ at infinite dilution were calculated from the experimental γ 13 ∞ values obtained over the temperature range. The selectivities for aliphatic/aromatic hydrocarbons separation problem were calculated from the γ 13 ∞ and compared to the literature values for other ionic liquids based on bis(trifluoromethylsulfonyl)-amide anion, NMP and sulfolane. It was found that the investigated ionic liquid shows much higher selectivity at infinite dilution than the general used organic solvents such as NMP, sulfolane and other ionic liquids. Additionally the selectivities for selected compounds which form azeotropic mixtures were calculated.

Excess Gibbs energy for six binary solid solutions of molecularly simple substances

Energy Technology Data Exchange (ETDEWEB)

Lobo, L J; Staveley, L A.K.

1985-01-01

In this paper we apply the method developed in a previous study of Ar + CH/sub 4/ to the evaluation of the excess Gibbs energy G /SUP E.S/ for solid solutions of two molecularly simple components. The method depends on combining information on the excess Gibbs energy G /SUP E.L/ for the liquid mixture of the two components with a knowledge of the (T, x) solid-liquid phase diagram. Certain thermal properties o the pure substances are also needed. G /SUP E.S/ has been calculated for binary mixtures of Ar + Kr, Kr + CH/sub 4/, CO + N/sub 2/, Kr + Xe, Ar + N/sub 2/, and Ar + CO. In general, but not always, the solid mixtures are more non-ideal than the liquid mixtures of the same composition at the same temperature. Except for the Kr + CH/sub 4/ system, the ratio r = G /SUP E.S/ /G /SUP E.L/ is larger the richer the solution in the component with the smaller molecules.

B-site substituted solid solutions on the base of sodium-bismuth titanate

Directory of Open Access Journals (Sweden)

V. M. Ishchuk

2016-12-01

Full Text Available The paper presents results of studies of the formation of phases during the solid-state synthesis in the [(Na0.5Bi0.50.80Ba0.20](Ti1–yByO3 system of solid solutions with B-site substitutions. The substitutions by zirconium, tin and ion complexes (In0.5Nb0.5 and (Fe0.5Nb0.5 have been studied. It has been found that the synthesis is a multi-step process associated with the formation of a number of intermediate phases (depending on the compositions and calcination temperatures. Single-phase solid solutions have been produced at the calcination temperatures in the interval 1000–1100∘C. An increase in the substituting ions concentration leads to a linear increase of the crystal cell size. At the same time, the tolerance factor gets reduced boosting the stability of the antiferroelectric phase as compared to that of the ferroelectric phase.

Activity coefficients at infinite dilution and physicochemical properties for organic solutes and water in the ionic liquid 1-(2-methoxyethyl)-1-methylpiperidinium bis(trifluoromethylsulfonyl)-amide

International Nuclear Information System (INIS)

Marciniak, Andrzej; Wlazło, Michał

2012-01-01

Highlights: The and KL for 61 solutes in the ionic liquid [COC2mPIP][NTf2] were determined by IGC at different temperatures. ► The partial molar excess Gibbs energies, enthalpies and entropies at infinite dilution were calculated. ► The selectivities for selected compounds which form azeotropic mixtures were calculated and compared to other ILs. ► LFER system constants as a function of temperature for [COC2mPIP][NTf2] were calculated. - Abstract: The activity coefficients at infinite dilution, γ ∞ and gas–liquid partition coefficients, K L for 61 solutes: alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, alcohols, thiophene, ethers, ketones, esters, 1-nitropropane, butanal, acetonitrile, and water in the ionic liquid 1-(2-methoxyethyl)-1-methylpiperidinium bis(trifluoromethylsulfonyl)-amide were determined by inverse gas chromatography at the temperatures from (318.15 to 368.15) K. The partial molar excess Gibbs free energies ΔG 1 E,∞ , enthalpies ΔH 1 E,∞ and entropies ΔS 1 E,∞ at infinite dilution were calculated from the experimental γ ∞ values obtained over the temperature range. The selectivities for selected compounds, which form azeotropic mixtures, were calculated from the γ ∞ and compared to the literature values for other ionic liquids based on bis(trifluoromethylsulfonyl)-amide anion.

Activity coefficients at infinite dilution measurements for organic solutes and water in the ionic liquid 4-methyl-N-butyl-pyridinium bis(trifluoromethylsulfonyl)-imide

International Nuclear Information System (INIS)

Domanska, Urszula; Marciniak, Andrzej

2009-01-01

The activity coefficients at infinite dilution, γ 13 ∞ for 36 solutes: alkanes, cycloalkanes, alkenes, alkynes, aromatic hydrocarbons, alcohols, thiophene, tetrahydrofuran, ethers, acetone, and water in the ionic liquid 4-methyl-N-butyl-pyridinium bis(trifluoromethylsulfonyl)-imide [bmPY][NTf 2 ] were determined by gas-liquid chromatography at temperatures from 298.15 K to 368.15 K. The partial molar excess enthalpies at infinite dilution values ΔH 1 E,∞ were calculated from the experimental γ 13 ∞ values obtained over the temperature range. The selectivity for different separation problems were calculated from the γ 13 ∞ and compared to the literature values for other ionic liquids, N-methyl-2-pyrrolidinone (NMP) and sulfolane.

Solution and solid-state electrochemiluminescence of a fac-tris(2-phenylpyridyl)iridium(III)-cored dendrimer

International Nuclear Information System (INIS)

Reid, Ellen F.; Burn, Paul L.; Lo, Shih-Chun; Hogan, Conor F.

2013-01-01

The solution phase and solid-state electrochemistry and electrochemiluminescence (ECL) of an iridium(III) complex-cored dendrimeric analogue of Ir(ppy) 3 , (G1pIr), are reported. The solid-state electrochemistry and solid-state ECL of Ir(ppy) 3 itself is also described for the first time. In solution phase, the dendrimer displays greater immunity to oxygen quenching in photoluminescence (PL) experiments and exhibits greater ECL efficiency compared to the parent Ir(ppy) 3 core under the same conditions, despite a lower photoluminescence quantum yield. It is proposed that the dendrons which effectively shield the core from PL quenching interactions in the solid-state counteract the effects of parasitic side-reactions during the solution ECL experiments. Electroactive and ECL-active solid-state films of both Ir(ppy) 3 and G1pIr were produced by drop-coating on boron doped diamond electrodes. Films of Ir(ppy) 3 produced stable co-reactant ECL. However, films of G1pIr produced lower than expected ECL intensity. This was attributed to poorer charge transport and the lipophilicity of the film limiting the rate of interaction with the co-reactant required for formation of the excited state

Structural transformation in mechanosynthesized bcc Fe-Al-Si(Ge) solid solutions during heating

International Nuclear Information System (INIS)

Kubalova, L.M.; Sviridov, I.A.; Vasilyeva, O.Ya.; Fadeeva, V.I.

2007-01-01

X-ray diffractometry and Moessbauer spectroscopy study of Fe 50 Al 25 Si 25 and Fe 50 Al 25 Ge 25 alloys obtained by mechanical alloying (MA) of elementary powders was carried out. Phase transformation during heating of synthesized products was studied using differential scanning calorimetry (DSC). After 2.5 h of MA monophase alloys containing bcc Fe(Al, Ge) solid solutions Fe(Al, Si) are formed. Fe(Al, Si) is partially ordered B2 type and Fe(Al, Ge) is completely disordered. DSC curves of synthesized alloys displayed the presence of exothermal peaks caused by phase transformation. The metastable Fe(Al, Si) solid solution transformed into FeAl 1-x Si x (B2) and FeSi 1-x Al x (B20) equilibrium phases. The Fe(Al, Ge) solid solution transformed into equilibrium phases through intermediate stage of Fe 6 Ge 3 Al 2 metastable phase formation. The Fe 6 Ge 3 Al 2 phase dissociated into three equilibrium phases: FeAl 1-x Ge x (B2), χ-Fe 6 Ge 5 and η-Fe 13 (Ge, Al) 8 (B8 2 ). The structure of Fe 6 Ge 3 Al 2 was calculated by Rietveld method, the distribution of Al and Ge in the elementary cell and its parameters were calculated. Moessbauer study showed that Fe(Al, Si) and Fe(Al, Ge) solid solutions are paramagnetic. In the equilibrium state the alloy containing Si is also paramagnetic while the alloy with Ge showed ferromagnetic properties

Interaction Studies of Dilute Aqueous Oxalic Acid

Directory of Open Access Journals (Sweden)

Kiran Kandpal

2007-01-01

Full Text Available Molecular conductance λm, relative viscosity and density of oxalicacid at different concentration in dilute aqueous solution were measured at 293 K.The conductance data were used to calculate the value association constant.Viscosity and density data were used to calculate the A and B coefficient ofJone-Dole equation and apparent molar volume respectively. The viscosityresults were utilized for the applicability of Modified Jone-Dole equation andStaurdinger equations. Mono oxalate anion acts, as structure maker and thesolute-solvent interaction were present in the dilute aqueous oxalic acid.

Influence of chemical heterogeneity of solid solutions on brittleness in chromium steels

International Nuclear Information System (INIS)

Madyanov, S.A.; Sedov, V.K.; Apaev, B.A.

1985-01-01

The role of chemical heterogeneity of solid solutions in formation of mechanical properties of Kh09, Kh15, Kh20, Kh19N2G5T chromium steels has been investigated. It is established that besides the known regioA of chemical heterogeneity in the vicinity of 475 deg C exists a high-temperature region (1000-1050 deg C), where maximum heteroge=- neity of chromium distribution in solid solution, is observed. Both types of chemical heterogeneity cause essential hardening of alloys, which becomes apparent in abrupt change of capability to microplastic deformation The mechanism of occurrence of the given temper brittleness consists in carbon diffusion into microvolunes enriched in carbide-forming elements

Solid substrate fermentation

Energy Technology Data Exchange (ETDEWEB)

Tengerdy, R P

1985-04-01

Solid Substrate Fermentation (SSF) describes the microbiological tranformation of biological materials in their natural state, in contrast with liquid or submerged fermentations which are carried out in dilute solutions or slurries. The most important industrial microorganisms used in SSF are filamentous fungi and the critical factors in their growth are the control of the moisture level and the temperature. Traditionally, most SSFs are conducted in shallow trays (so that heat build up is avoided) and stacked in a moist chamber, however, the modern SSF should be able to mix large amounts of substrate for a uniform fermentation, maximum automization scale-up of the process, continuous operation and fermentation control and a promising new design is the Helical screw fermenter. At the present time SSF is used in the production of foods (e.g. mushrooms and oriental foods) in municipal, agricultural and industrial solid waste disposal and in the production of enzymes and speciality chemicals but it does not seem likely that it will replace prevalent liquid fermentation technologies. 29 references.

Cementation of the solid radioactive waste with polymer-cement solutions using the method of impregnation

International Nuclear Information System (INIS)

Gorbunova, O.

2015-01-01

Cementation of solid radioactive waste (SRW), i.e. inclusion of solid radioactive waste into cement matrix without cavities - is one of the main technological processes used for conditioning low and intermediate level radioactive waste. At FSUE 'Radon' the industrialized method of impregnation has been developed and since 2003 has been using for cementation of solid radioactive waste. The technology is that the polymer-cement solution, having high penetrating properties, is supplied under pressure through a tube to the bottom of the container in which solid radioactive waste has preliminarily been placed. The polymer-cement solution is evenly moving upwards through the channels between the particles of solid radioactive waste, fills the voids in the bulk volume of the waste and hardens, forming a cement compound, the amount of which is equal to the original volume. The aim of the investigation was a selection of a cement solution suitable for SRW impregnation (including fine particles) without solution depletion and bottom layers stuffing. It has been chosen a polymer: PHMG (polyhexamethylene-guanidine), which is a stabilizing and water-retaining component of the cement solution. The experiments confirm that the polymer increases the permeability of the cement solution by a 2-2.5 factor, the viscosity by a 1.2 factor, the stability of the consistency by a 1.5-1.7 factor, and extends the operating range of the W/C ratio to 0.5-1.1. So it is possible to penetrate a volume of SRW bigger by a 1.5-2.0 factor. It has been proved, that PHMG polymer increases strength and frost-resistance of the final compounds by a 1.8-2.7 factor, and contributes to fast strength development at the beginning of hardening and it decreases Cs-137 leashing rate by a 1.5-2 factor

Crystal chemical analysis of formation of solid solutions on the basis of compounds with garnet structure

International Nuclear Information System (INIS)

Kuz'micheva, G.M.; Kozlikin, S.N.

1989-01-01

Crystal chemical formulas permitting to evaluate the character of changes in interatomic distances during isomorphous substitution and, hence, the probability of formation of internal solid solutions and successive isomorphous substitution, are presented. The possibility of formation of introduction solid solutions is considered, using as an example Sc, Y oxides, rare earths with garnet structure

Thermodynamics of CoAl2O4-CoGa2O4 solid solutions

International Nuclear Information System (INIS)

Lilova, Kristina I.; Navrotsky, Alexandra; Melot, Brent C.; Seshadri, Ram

2010-01-01

CoAl 2 O 4 , CoGa 2 O 4 , and their solid solution Co(Ga z Al 1-z ) 2 O 4 have been studied using high temperature oxide melt solution calorimetry in molten 2PbO.B 2 O 3 at 973 K. There is an approximately linear correlation between lattice parameters, enthalpy of formation from oxides, and the Ga content. The experimental enthalpy of mixing is zero within experimental error. The cation distribution parameters are calculated using the O'Neill and Navrotsky thermodynamic model. The enthalpies of mixing calculated from these parameters are small and consistent with the calorimetric data. The entropies of mixing are calculated from site occupancies and compared to those for a random mixture of Ga and Al ions on octahedral site with all Co tetrahedral and for a completely random mixture of all cations on both sites. Despite a zero heat of mixing, the solid solution is not ideal in that activities do not obey Raoult's Law because of the more complex entropy of mixing. - Graphical abstract: Measured enthalpies of mixing of CoAl 2 O 4 -CoGa 2 O 4 solid solutions are close to zero but entropies of mixing reflect the complex cation distribution, so the system is not an ideal solution.

Investigation of samarium solubility in the magnesium based solid solution

International Nuclear Information System (INIS)

Rokhlin, L.L.; Padezhnova, E.M.; Guzej, L.S.

1976-01-01

Electric resistance measurements and microscopic analysis were used to investigate the solubility of samarium in a magnesium-based solid solution. The constitutional diagram Mg-Sm on the magnesium side is of an eutectic type with the temperature of the eutectic transformation of 542 deg C. Samarium is partly soluble in solid magnesium, the less so, the lower is the temperature. The maximum solubility of samarium in magnesium (at the eutectic transformation point) is 5.8 % by mass (0.99 at. %). At 200 deg C, the solubility of samarium in magnesium is 0.4 % by mass (0.063 at. %)

Cefuroxime axetil solid dispersions prepared using solution enhanced dispersion by supercritical fluids.

Science.gov (United States)

Jun, Seoung Wook; Kim, Min-Soo; Jo, Guk Hyun; Lee, Sibeum; Woo, Jong Soo; Park, Jeong-Sook; Hwang, Sung-Joo

2005-12-01

Cefuroxime axetil (CA) solid dispersions with HPMC 2910/PVP K-30 were prepared using solution enhanced dispersion by supercritical fluids (SEDS) in an effort to increase the dissolution rate of poorly water-soluble drugs. Their physicochemical properties in solid state were characterized by differential scanning calorimeter (DSC), powder X-ray diffraction (PXRD), Fourier transform infrared spectrometry (FT-IR) and scanning electron microscopy. No endothermic and characteristic diffraction peaks corresponding to CA were observed for the solid dispersions in DSC and PXRD. FTIR analysis demonstrated the presence of intermolecular hydrogen bonds between CA and HPMC 2910/PVP K-30 in solid dispersions, resulting in the formation of amorphous or non-crystalline CA. Dissolution studies indicated that the dissolution rates were remarkably increased in solid dispersions compared with those in the physical mixture and drug alone. In conclusion, an amorphous or non-crystalline CA solid dispersion prepared using SEDS could be very useful for the formulation of solid dosage forms.

Influence of hydrostatic pressure on BCC-lattice parameter in molybdenum, niobium and vanadium with rhenium solid solutions

International Nuclear Information System (INIS)

Smol'yaninova, Eh.A.; Stribuk, E.K.; Tyavlovskij, V.I.

1987-01-01

Data on the effect of 1.8GPa hydrostatic pressure on bcc lattice parameters of solid solutions in Mo-Re, Nb-Re, V-re systems are presented. It is shown that after the application hydrostatic pressure a decrease in bcc lattice parameter is observed and the greatest change in the lattice parameter takes place in bcc of solid solutions in the Nb-Re system (DELTA A ∼ 0.0035 nm). Analysis of the experimental data obtained on the basis of calculations made for packing density change in the above-mentioned solid solutions under the pressure is carried out

Electron pairing in dilute liquid metal-metal halide solutions

Energy Technology Data Exchange (ETDEWEB)

Selloni, A.; Car, R.; Parrinello, M.; Carnevali, P.

1987-09-10

Spin density functional theory is used to describe the interaction between solvated electrons in KCl in the high dilution limit. In agreement with recent calculations based on the path integral method our results for antiparallel spin predict a strong tendency to form localized bielectronic complexes. At variance with numerical path integral, our method can efficiently treat the case of parallel spins. For this case we find that electrons repel each other and localize into separate F-center-like states.

Effect of pH Value on the Electrochemical and Stress Corrosion Cracking Behavior of X70 Pipeline Steel in the Dilute Bicarbonate Solutions

Science.gov (United States)

Cui, Z. Y.; Liu, Z. Y.; Wang, L. W.; Ma, H. C.; Du, C. W.; Li, X. G.; Wang, X.

2015-11-01

In this work, effects of pH value on the electrochemical and stress corrosion cracking (SCC) behavior of X70 pipeline steel in the dilute bicarbonate solutions were investigated using electrochemical measurements, slow strain rate tensile tests and surface analysis techniques. Decrease of the solution pH from 6.8 to 6.0 promotes the anodic dissolution and cathodic reduction simultaneously. Further decrease of the pH value mainly accelerates the cathodic reduction of X70 pipeline steel. As a result, when the solution pH decreases form 6.8 to 5.5, SCC susceptibility decreases because of the enhancement of the anodic dissolution. When the solution pH decreases from 5.5 to 4.0, SCC susceptibility increases gradually because of the acceleration of cathodic reactions.

Activity coefficients at infinite dilution of organic solutes in the ionic liquid 1-ethyl-3-methylimidazolium trifluoromethanesulfonate using gas-liquid chromatography at T = (313.15, 323.15, and 333.15) K

International Nuclear Information System (INIS)

Olivier, Eugene; Letcher, Trevor M.; Naidoo, Paramespri; Ramjugernath, Deresh

2010-01-01

Activity coefficients at infinite dilution were determined for 24 solutes (n-alkanes, alk-1-enes, alk-1-ynes, cycloalkanes, alkylbenzenes, and alcohols) in the ionic liquid 1-ethyl-3-methylimidazolium trifluoromethanesulfonate by gas-liquid chromatography at three different temperatures T = (313.15, 323.15, 333.15) K. The partial molar excess enthalpy values at infinite dilution were calculated from the experimental results over the same temperature range. Selectivities and capacities at infinite dilution for the hexane/benzene and methanol/benzene separation problems were calculated from experimental infinite dilution activity coefficient values. The activity coefficients, enthalpies, selectivities, and capacities are discussed and compared to literature values for other ionic liquids, as well as industrial molecular solvents.

''Over the horizon'' SANS: Measurements on near-surface Poiseuille shear-induced ordering of dilute solutions of threadlike micelles

International Nuclear Information System (INIS)

Hamilton, W.A.; Butler, P.D.; Hayter, J.B.; Magid, L.J.; Kreke, P.J.

1995-01-01

Although the behavior of a fluid under shear near a surface can be expected to be critically important to its drag and lubrication properties, most shear measurements to date have been of the bulk. This paper outlines the use of a specially developed Poiseuille shear cell at grazing incidence to measure the small-angle neutron scattering (SANS) signal from the first few tens of microns in the interfacial region. The authors illustrate the technique with measurements made on the near-surface ordering in flow past a quartz surface of dilute surfactant solutions comprising highly extended self-assembling ''threadlike'' micelles

Regularities in electroconductivity and thermo-emf in systems of binary continuous solid solutions of metals

International Nuclear Information System (INIS)

Vedernikov, M.V.; Dvunitkin, V.G.; Zhumagulov, A.

1978-01-01

Given are new experimental data about specific electric resistance of 10 systems of binary continuous solid metal solutions at the temperatures of 293 and 4.2 K: Cr-V, Mo-Nb, Mo-V, Cr-Mo, Nb-V, Ti-Zr, Hf-Zr, Hf-Ti, Sc-Zr, Sc-Hf. For the first time a comparative analysis of all available data on the resistance dependence on the composition of systems of continuous solid solutions, which covers 21 systems, is carried out. The ''resistance-composition'' dependence for such alloy systems is found to be of two types. The dependence of the first type is characteristic of the systems, formed by two isoelectronic metals, the dependence of the second type - for the systems, formed by non-isoelectronic metals. Thermo-emf of each type of solid solutions differently depends on their compositions

Dilution thermodynamics of the biologically relevant cation mixtures

International Nuclear Information System (INIS)

Kaczyński, Marek; Borowik, Tomasz; Przybyło, Magda; Langner, Marek

2014-01-01

Graphical abstract: - Highlights: • Dilution energetics of Ca 2+ can be altered by the aqueous phase ionic composition. • Dissipated heat upon Ca 2+ dilution is drastically reduced in the K + presence. • Reduction of the enthalpy change upon Ca 2+ dilution is K + concentration dependent. • The cooperativity of Ca 2+ hydration might be of great biological relevance providing a thermodynamic argument for the specific ionic composition of the intracellular environment. - Abstract: The ionic composition of intracellular space is rigorously controlled by a variety of processes consuming large quantities of energy. Since the energetic efficiency is an important evolutional criterion, therefore the ion fluxes within the cell should be optimized with respect to the accompanying energy consumption. In the paper we present the experimental evidence that the dilution enthalpies of the biologically relevant ions; i.e. calcium and magnesium depend on the presence of monovalent cations; i.e. sodium and potassium. The heat flow generated during the dilution of ionic mixtures was measured with the isothermal titration calorimetry. When calcium was diluted together with potassium the dilution enthalpy was drastically reduced as the function of the potassium concentration present in the solution. No such effect was observed when the potassium ions were substituted with sodium ones. When the dilution of magnesium was investigated the dependence of the dilution enthalpy on the accompanying monovalent cation was much weaker. In order to interpret experimental evidences the ionic cluster formation is postulated. The specific organization of such cluster should depend on ions charges, sizes and organization of the hydration layers

First-Principles Modeling of ThO2 Solid Solutions with Oxides of Trivalent Cations

Science.gov (United States)

Alexandrov, Vitaly; Asta, Mark; Gronbech-Jensen, Niels

2010-03-01

Solid solutions formed by doping ThO2 with oxides of trivalent cations, such as Y2O3 and La2O3, are suitable for solid electrolyte applications, similar to doped zirconia and ceria. ThO2 has also been gaining much attention as an alternative to UO2 in nuclear energy applications, the aforementioned trivalent cations being important fission products. In both cases the mixing energetics and short-range ordering/clustering are key to understanding structural and transport properties. Using first-principles atomistic calculations, we address intra- and intersublattice interactions for both cation and anion sublattices in ThO2-based fluorite-type solid solutions and compare the results with similar modeling studies for related trivalent-doped zirconia systems.

Activity coefficients at infinite dilution and physicochemical properties for organic solutes and water in the ionic liquid 1-(3-hydroxypropyl)pyridinium bis(trifluoromethylsulfonyl)-amide

Energy Technology Data Exchange (ETDEWEB)

Marciniak, Andrzej, E-mail: a.marciniak@ch.pw.edu.pl [Department of Physical Chemistry, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw (Poland)

2011-10-15

Highlights: > The {gamma}{sub 13}{sup {infinity}} and KL for 46 solutes in the ionic liquid [N-C3OHPY][NTf2] were determined by GLC at different temperatures. > The partial molar excess Gibbs energies {Delta}G{sub 1}{sup E,{infinity}}, enthalpies {Delta}H{sub 1}{sup E,{infinity}} and entropies {Delta}S{sub 1}{sup E,{infinity}} at infinite dilution were calculated. > The selectivities for aliphatics/aromatics hydrocarbons separation problem were calculated and compared to other ILs, NMP and sulfolane. > The selectivities for selected compounds which form azeotropic mixtures were calculated. - Abstract: The activity coefficients at infinite dilution, {gamma}{sub 13}{sup {infinity}} and gas-liquid partition coefficients, K{sub L} for 46 solutes: alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, alcohols, thiophene, ethers, ketones, acetic acid, and water in the ionic liquid 1-(3-hydroxypropyl)pyridinium bis(trifluoromethylsulfonyl)-amide were determined by gas-liquid chromatography at the temperatures from (308.15 to 378.15) K. The partial molar excess Gibbs free energies {Delta}G{sub 1}{sup E,{infinity}}, enthalpies {Delta}H{sub 1}{sup E,{infinity}} and entropies {Delta}S{sub 1}{sup E,{infinity}} at infinite dilution were calculated from the experimental {gamma}{sub 13}{sup {infinity}} values obtained over the temperature range. The selectivities for aliphatic/aromatic hydrocarbons separation problem were calculated from the {gamma}{sub 13}{sup {infinity}} and compared to the literature values for other ionic liquids based on bis(trifluoromethylsulfonyl)-amide anion, NMP and sulfolane. It was found that the investigated ionic liquid shows much higher selectivity at infinite dilution than the general used organic solvents such as NMP, sulfolane and other ionic liquids. Additionally the selectivities for selected compounds which form azeotropic mixtures were calculated.

Gas-liquid chromatography measurements of activity coefficients at infinite dilution of various organic solutes and water in tri-iso-butylmethylphosphonium tosylate ionic liquid

International Nuclear Information System (INIS)

Domanska, Urszula; Paduszynski, Kamil

2010-01-01

Activity coefficients at infinite dilution (γ 13 ∞ ) of 33 different solutes (including alkanes, cycloalkanes, alkenes, alkynes, benzene, alkylbenzenes, water, alcohols, MTBE, thiophene and THF) in the ionic liquid tri-iso-butylmethylphosphonium tosylate have been determined by using the GLC method and have been reported over the temperature range (298.15 to 368.15) K. The partial molar excess enthalpies of mixing at infinite dilution have been determined based on temperature dependence of γ 13 ∞ . Selectivity and capacity at infinite dilution has been also calculated for exemplary separation processes in systems n-hexane/benzene and n-hexane/thiophene, to evaluate if the studied ionic liquid is capable to be a good entrainer for these processes, e.g. in the liquid-liquid extraction. The obtained results are promising however the ionic liquid studied shows a lower selectivity than some of imidazolium-based ionic liquids. To our best knowledge, the results indicate that tri-iso-butylmethylphosphonium tosylate is the best for the separation problem of aliphatic hydrocarbons from aromatic hydrocarbons among all of the studied quaternary phosphonium-based ionic liquids.

Activity coefficients at infinite dilution measurements for organic solutes and water in the ionic liquid 4-methyl-N-butyl-pyridinium bis(trifluoromethylsulfonyl)-imide

Energy Technology Data Exchange (ETDEWEB)

Domanska, Urszula [Physical Chemistry Department, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw (Poland)], E-mail: ula@ch.pw.edu.pl; Marciniak, Andrzej [Physical Chemistry Department, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw (Poland)

2009-12-15

The activity coefficients at infinite dilution, {gamma}{sub 13}{sup {infinity}} for 36 solutes: alkanes, cycloalkanes, alkenes, alkynes, aromatic hydrocarbons, alcohols, thiophene, tetrahydrofuran, ethers, acetone, and water in the ionic liquid 4-methyl-N-butyl-pyridinium bis(trifluoromethylsulfonyl)-imide [bmPY][NTf{sub 2}] were determined by gas-liquid chromatography at temperatures from 298.15 K to 368.15 K. The partial molar excess enthalpies at infinite dilution values {delta}H{sub 1}{sup E,{infinity}} were calculated from the experimental {gamma}{sub 13}{sup {infinity}} values obtained over the temperature range. The selectivity for different separation problems were calculated from the {gamma}{sub 13}{sup {infinity}} and compared to the literature values for other ionic liquids, N-methyl-2-pyrrolidinone (NMP) and sulfolane.

Phase coexistence in ferroelectric solid solutions: Formation of monoclinic phase with enhanced piezoelectricity

Directory of Open Access Journals (Sweden)

Xiaoyan Lu

2016-10-01

Full Text Available Phase morphology and corresponding piezoelectricity in ferroelectric solid solutions were studied by using a phenomenological theory with the consideration of phase coexistence. Results have shown that phases with similar energy potentials can coexist, thus induce interfacial stresses which lead to the formation of adaptive monoclinic phases. A new tetragonal-like monoclinic to rhombohedral-like monoclinic phase transition was predicted in a shear stress state. Enhanced piezoelectricity can be achieved by manipulating the stress state close to a critical stress field. Phase coexistence is universal in ferroelectric solid solutions and may provide a way to optimize ultra-fine structures and proper stress states to achieve ultrahigh piezoelectricity.

Experimental studies in solid state and low temperature physics. Progress report, 1975

International Nuclear Information System (INIS)

Goldman, A.M.; Weyhmann, W.V.; Zimmermann, W. Jr.

1975-09-01

Experimental investigations are being carried out in a broad area of low-temperature and solid-state physics which includes superconductivity, magnetism in metals and liquid and solid helium. The pair-field susceptibility of superconductors is being studied. A propagating mode in the phase of the superconducting order parameter has been found. Heat capacities of superconducting films in the vicinity of T/sub c/ are also being investigated. An investigation in the time-dependent high conductivity of dilute solid solutions of sodium in ammonia has been initiated. Nuclear orientation studies of the dilute magnetic impurity problem in metals in the 1 mK temperature region are being carried out. Refrigeration requirements for this work are being met using enhanced hyperfine nuclear cooling. Measurements of the differential osmotic pressure of 3 He/ 4 He liquid mixtures near the tricritical point have shown a peak in the ''concentration susceptibility'' at the lambda line. Data obey a simple tricritical scaling relation. The dynamics of superfluid flow through submicron pores are being studied in both pure 4 He and in 3 He/ 4 He mixtures in an apparatus provided with a 3 He refrigerator. The quantization of circulation in superfluid liquid 4 He is being investigated using the Vinen method. The low temperature heat capacity of bcc solid 3 He is being studied

Dilution and Mixing in transient velocity fields: a first-order analysis

Science.gov (United States)

Di Dato, Mariaines; de Barros, Felipe, P. J.; Fiori, Aldo; Bellin, Alberto

2017-04-01

An appealing remediation technique is in situ oxidation, which effectiveness is hampered by difficulties in obtaining good mixing of the injected oxidant with the contaminant, particularly when the contaminant plume is contained and therefore its deformation is physically constrained. Under such conditions (i.e. containment), mixing may be augmented by inducing temporal fluctuations of the velocity field. The temporal variability of the flow field may increase the deformation of the plume such that diffusive mass flux becomes more effective. A transient periodic velocity field can be obtained by an engineered sequence of injections and extractions from wells, which may serve also as a hydraulic barrier to confine the plume. Assessing the effectiveness of periodic flows to maximize solute mixing is a difficult task given the need to use a 3D setup and the large number of possible flow configurations that should be analyzed in order to identify the optimal one. This is the typical situation in which analytical solutions, though approximated, may assist modelers in screening possible alternative flow configurations such that solute dilution is maximized. To quantify dilution (i.e. a precondition that enables reactive mixing) we utilize the concept of the dilution index [1]. In this presentation, the periodic flow takes place in an aquifer with spatially variable hydraulic conductivity field which is modeled as a Stationary Spatial Random Function. We developed a novel first-order analytical solution of the dilution index under the hypothesis that the flow can be approximated as a sequence of steady state configurations with the mean velocity changing with time in intensity and direction. This is equivalent to assume that the characteristic time of the transient behavior is small compared to the period characterizing the change in time of the mean velocity. A few closed paths have been analyzed quantifying their effectiveness in enhancing dilution and thereby mixing

Conformation of Single Pentablock Ionomer Chains in Dilute Solutions

Energy Technology Data Exchange (ETDEWEB)

Aryal, Dipak [Clemson Univ., SC (United States); Perahia, Dvora [Clemson Univ., SC (United States); Grest, Gary S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2015-04-01

The conformation of single chain pentablock ionomers (A-B-C-B-A) containing randomly sulfonated polystyrene in the center block, tethered to poly-ethylene-r-propylene end-capped by poly-t-butyl styrene is studied in dilute solutions by molecular dynamics simulations. Multi-block copolymers offer a means to tailor several properties into one molecule, taking advantage of their rich phase diagram together with unique properties of specific blocks. For this pentablock the ionic block facilitates transport while the A and B components are incorporated for mechanical stability. The present study investigates the confirmation of a single chain of pentablock ionomer of molecular weight M_w ~ 50,000 g/mol and sulfonated polystyrene of the same molecular weight as that of the center block for six sulfonation fractions f from f=0.0-0.55. For the sulfonated systems Na⁺ counterions are included. Results for the equilibrium conformation of the chains and the three blocks in water and 1:1 mixture of cyclohexane and n-heptane are compared to simulations in implicit poor solvents with dielectric constants ε =1.0 and 77.73. In water, the pentablock is collapsed with sulfonated groups on the outer surface. As the sulfonation fraction f increases, the ionic, center block is increasingly segregated from the hydrophobic regions. In the 1:1 mixture of cyclohexane and heptane both the flexible and end blocks are swollen while the center ionic block is collasped for f>0, while for f=0 all blocks are swollen. In both implicit poor solvents the pentablock is collapsed into a nearly spherical shape for all f. The sodium counterions are dispersed widely throughout the simulation cell for both water and ε =77.73 whereas for ε =1.0 the counterions are largely condensed on the collapsed pentablock.

Enthalpies of the dissolution and dilution of aqueous solutions of rubidium and cesium diclofenac at 293.15-318.15 K

Science.gov (United States)

Manin, N. G.; Perlovich, G. L.; Fini, A.

2014-03-01

Enthalpies of the dissolution and dilution of aqueous solutions of rubidium and cesium diclofenac (RbDC and CsDC) are measured at 293.15, 298.15, 308.15, and 318.15 K at concentrations of water of less than 0.1 mol/kg. The heat capacity of RbDC and CsDC crystal salts is determined. Changes in the thermodynamic properties of both a solution and its components vs. concentration and temperature is considered. An increase in the endothermicity of the dissolution of RbDC and CsDC with a rise in temperature is noted. It is shown that the dissolution of both RbDC and CsDC electrolytes in water is determined by the contribution from entropy. It is shown that in aqueous solutions of RbDC and CsDC, the degree of binding of water molecules is higher than in pure water at temperatures below 303.15 K.

Buffer erosion in dilute groundwater

International Nuclear Information System (INIS)

Schatz, T.; Kanerva, N.; Martikainen, J.; Sane, P.; Olin, M.; Seppaelae, A.; Koskinen, K.

2013-08-01

One scenario of interest for repository safety assessment involves the loss of bentonite buffer material in contact with dilute groundwater flowing through a transmissive fracture interface. In order to examine the extrusion/erosion behavior of bentonite buffer material under such circumstances, a series of experiments were performed in a flow-through, 1 mm aperture, artificial fracture system. These experiments covered a range of solution chemistry (salt concentration and composition), material composition (sodium montmorillonite and admixtures with calcium montmorillonite), and flow velocity conditions. No erosion was observed for sodium montmorillonite against solution compositions from 0.5 g/L to 10 g/L NaCl. No erosion was observed for 50/50 calcium/sodium montmorillonite against 0.5 g/L NaCl. Erosion was observed for both sodium montmorillonite and 50/50 calcium/sodium montmorillonite against solution compositions ≤ 0.25 g/L NaCl. The calculated erosion rates for the tests with the highest levels of measured erosion, i.e., the tests run under the most dilute conditions (ionic strength (IS) < ∼1 mM), were well-correlated to flow velocity, whereas the calculated erosion rates for the tests with lower levels of measured erosion, i.e., the tests run under somewhat less dilute conditions (∼1 mM < IS < ∼4 mM), were not similarly correlated indicating that material and solution composition can significantly affect erosion rates. In every experiment, both erosive and non-erosive, emplaced buffer material extruded into the fracture and was observed to be impermeable to water flowing in the fracture effectively forming an extended diffusive barrier around the intersecting fracture/buffer interface. Additionally, a model which was developed previously to predict the rate of erosion of bentonite buffer material in low ionic strength water in rock fracture environments was applied to three different cases: sodium montmorillonite expansion in a vertical tube, a

Thermodynamics and activity coefficients at infinite dilution for organic solutes and water in the ionic liquid 1-butyl-1-methylmorpholinium tricyanomethanide

International Nuclear Information System (INIS)

Domańska, Urszula; Lukoshko, Elena Vadimovna

2014-01-01

Highlights: • Measurements of activity coefficients at infinite dilution using GLC. • Sixty one organic solvents in the ionic liquid 1-butyl-1-methylmorpholinium tricyanomethanide. • High selectivity for heptane/thiophene, or pyridine, or 1-nitropropane. • The excess thermodynamic functions and the gas–liquid partition coefficients were presented. • Possible entrainer for the extraction of sulphur and nitrogen-compounds from alkanes. -- Abstract: The activity coefficients at infinite dilution, γ 13 ∞ , for 61 solutes, including alkanes, cycloalkanes, alkenes, alkynes, aromatic hydrocarbons, alcohols, water, thiophene, ethers, ketones, esters, aldehyde, acetonitrile, pyridine and 1-nitropropane in the ionic liquid (IL) 1-butyl-1-methylmorpholinium tricyanomethanide, [BMMOR][TCM] were determined by gas–liquid chromatography at six temperatures within the range of (318.15 to 368.15) K. The thermodynamic functions at infinite dilution as partial molar excess Gibbs free energy ΔG 1 E,∞ , enthalpy ΔH 1 E,∞ , and entropy term T ref ΔS 1 E,∞ were calculated from the experimental γ 13 ∞ values obtained over the temperature range. The density of [BMMOR][TCM] was measured over the temperature range (288.15 to 368.15) K. The gas–liquid partition coefficient K L was calculated for all solutes. The values of selectivity and capacity for a few separation problems such as hexane/benzene, cyclohexane/benzene, heptane/thiophene at T = 328.15 K were calculated from γ 13 ∞ and compared to literature values for similar ionic liquids, viz. N-methyl-2-pyrrolidinone (NMP), and sulfolane. In comparison with the previously measured values for [BMPYR][TCM], the morpholinium IL presents high selectivity for the separation of aromatic hydrocarbons from aliphatic hydrocarbons, and especially thiophene, or piridine from heptane with a slightly lower capacity. New data show that [BMMOR][TCM] IL may be proposed as an alternative solvent for the separation of

Measurements of activity coefficients at infinite dilution for organic solutes and water in the ionic liquid 1-butyl-1-methylpyrrolidinium tricyanomethanide

International Nuclear Information System (INIS)

Domańska, Urszula; Lukoshko, Elena Vadimovna

2013-01-01

Highlights: • Measurements of activity coefficients at infinite dilution using GLC. • 62 organic solvents and water in the ionic liquid 1-butyl-1-methylpyrrolidinium tricyanomethanide. • High capacity for thiophene, 1.37 at T = 328.15 K. • Possible entrainer for extraction of sulfur, or nitrogen compounds from fuels. • The excess thermodynamic functions and the gas–liquid partition coefficients were calculated. -- Abstract: The activity coefficients at infinite dilution, γ 13 ∞ , for 62 solutes, including alkanes, cycloalkanes, alkenes, alkynes, aromatic hydrocarbons, alcohols, water, thiophene, ethers, ketones, acetonitrile, pyridine and 1-nitropropane in the ionic liquid 1-butyl-1-methylpyrrolidinium tricyanomethanide, [BMPYR][TCM] were determined by gas–liquid chromatography at six temperatures over the range of (318.15 to 368.15) K. The partial molar excess Gibbs free energy, ΔG 1 E ∞, enthalpy ΔH 1 E ∞, and entropy term T ref ΔS 1 E ,∞ at infinite dilution were calculated from the experimental γ 13 ∞ values obtained over the temperature range. The densities of [BMPYR][TCM] were measured within temperature range from 318.15 K to 368.15 K. The gas–liquid partition coefficients, K L were calculated for all solutes. The values of selectivity for few separation problems as hexane/benzene, cyclohexane/benzene, heptane/thiophene were calculated from γ 13 ∞ and compared to literature values for N-methyl-2-pyrrolidinone (NMP), sulfolane, and other ionic liquids based on [BMPYR] + cation. In comparison with the former measured ILs, [BMPYR][TCM] present quite high selectivity for the separation of aromatic hydrocarbons and aliphatics hydrocarbons, an average capacity for benzene. The data presented here shows that [BMPYR][TCM] ionic liquid can be used as an alternative solvent for the separation of thiophene from the aliphatic hydrocarbons

Radiation induced homogeneous precipitation in undersaturated solid-solutions

International Nuclear Information System (INIS)

Cauvin, R.; Martin, G.

1979-01-01

A TEM study of 1 MeV electron irradiated Al 1.9 at% Zn solid solution shows that Zn precipitates form, under irradiation at temperatures well above the Zn solvus temperature outside irradiation. The corresponding upward shift of this temperature is dose rate dependent. This new example of radiation-induced precipitation exhibits unexpected features, which are not accounted for by the available models: (1) no correlation exists between the location of the precipitates and that of the point defects sinks; (2) the precipitation of incoherent β-phase with atomic volume smaller than that of the matrix, and of coherent G.P. zones both occurs; (3) the size of the coherent β precipitates saturates at large dose. A general mechanism for solute concentration fluctuations under irradiation is proposed which qualitatively accounts for the formation of coherent G.P. zones and for the nucleation of solute clusters with more complex structures. A reanalysis of Russell's model (1977) for the growth of incoherent precipitates shows that it may qualitatively account for the observed behavior of the β phase precipitates. (Auth.)

Uranothorite solid solutions: From synthesis to dissolution

International Nuclear Information System (INIS)

Costin, Dan-Tiberiu

2012-01-01

USiO 4 coffinite appears as one of the potential phases formed in the back-end of the alteration of spent fuel, in reducing storage conditions. A study aiming to assess the thermodynamic data associated with coffinite through an approach based on the preparation of Th 1-x U x SiO 4 uranothorite solid solutions was then developed during this work. First, the preparation of uranothorite samples was successfully undertaken in hydrothermal conditions. However, the poly-phased samples systematically formed for x ≥ 0,2 underlined the kinetic hindering linked with the preparation of uranium-enriched samples, including coffinite end-member. Nevertheless, the characterization of the various samples led to confirm the formation of an ideal solid solution and allowed the constitution of a spectroscopic database. The purification of the samples was then performed by the means of different protocols based on physical (dispersion-centrifugation) or chemical (selective dissolution of secondary phases) methods. This latter led to a complete of the impurities (Th 1-y U y O 2 mixed oxide and amorphous silica) through successive washing steps in acid then basic media. Finally, dissolution experiments were undertaken on uranothorite samples (0 ≤ xexp. ≤ 0,5) and allowed pointing out the influence of composition, pH and temperature on the normalized dissolution rate of the compounds. Also, the associated thermodynamic data, such as activation energy, indicate that the reaction is controlled by surface reactions. Once the equilibrium is reached, the analogous solubility constants were determined for each composition studied, then allowing the extrapolation to coffinite value. It was then finally possible to conclude on the inversion of coffinitisation reaction with temperature. (author) [fr

Lattice parameters and electrical resistivity of Ceria-Yttria solid solutions

International Nuclear Information System (INIS)

Rey, Jose Fernando Queiruga

2002-01-01

Ce0 2 :u mol% Y 2 O 3 (u=0, 4, 6, 8, 10 and 12) solid solutions were prepared by the conventional powder mixture technique. The main purposes of this work are: the study of the dependence of the lattice parameter of the Ceria cubic phase on the Yttria content, comparing the experimental data with data calculated according to the existing theoretical models; to determine the dependence of the ionic conductivity on the Yttria content; and to study the stability of the cubic fluorite phase after extensive thermal treatments (aging) of the Ceria-Yttria specimens. The results show that the lattice parameter of the solid solutions follows the Vegard's law and can be described by the two reported theoretical models. The 8 mol% Yttria-doped Ceria was found to present the largest value of ionic conductivity. Preliminary results show that a large decrease is found for only 1 h aging at 700 deg C and that the ionic conductivity decreases for ceramic specimens aged for times up to 10 h. (author)

Coherence and stiffness of spin waves in diluted ferromagnets

Czech Academy of Sciences Publication Activity Database

Turek, Ilja; Kudrnovský, Josef; Drchal, Václav

2016-01-01

Roč. 94, č. 17 (2016), č. článku 174447. ISSN 2469-9950 R&D Projects: GA ČR GA15-13436S Institutional support: RVO:68081723 ; RVO:68378271 Keywords : spin wave s * diluted ferromagnets * disordered systems Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.836, year: 2016

Effect of ionizing radiation on solid and water solution Penicillin G

International Nuclear Information System (INIS)

Ben Salem, I.; Amine, Kh.M.; Mabrouk, Y.; Saidi, M.; Mezni, M; Boulila, N; Hafez, E

2015-01-01

Penicillin G is a conventional antibiotic used for treatment of different kinds of infectious diseases. Due to its huge quantity production and resistance to biodegradability, this molecule has been a serious concern for clinicians and environmentalists. In this study, the effect of ionizing radiation on the penicillin G powder and in water solution was investigated. The Nuclear Magnetic Resonance (NMR) and fourier transform infrared spectroscopy (FTIR) analysis showed that the ionizing radiation at 50 kGy has no effect on the integrity of solid Penicillin G. The anti-microbial assays revealed that the activity of irradiated solid Penicillin G did not reduce and was stable after storage for one month. Ionizing radiation at 50 kGy led to degradation of water solution Penicillin G. The complete disappear of peaks observed in the control sample confirmed the broken of β-lactam ring, the decarboxylation and cleavage of the thiazolidine ring. The product issued from the irradiation of Penicillin G, was completely removed by the bacterium Cupriavidus.metallidurans. Thus, the ionizing irradiation followed by a biological treatment was very effective method for removing of Penicillin G antibiotics residuals from water solution.

Thorium-d-metals compounds and solid solutions

International Nuclear Information System (INIS)

Chachkhiani, Z.B.; Chechernikov, V.I.; Chachkhiani, L.G.

1986-01-01

Thorium compounds with Fe, Co, Ni dependence of their magnetic properties on temperature, pressure and concentration of the second element are considered. Anomalous magnetic behaviour of alloys in the Th-Fe system is noted. Special attention is paid to compounds with CaCu 5 type hexagonal structure and their solid solutions. Th-Co-Ni specimens containing up to 25% Ni are ferromagnetics and the rest are paramagnetics. Specimens with 60% cobalt content do not display ferromagnetic properties up to 4.2 K. Hydrides of Th 7 M 3 H 30 type (M - Fe, Co, Ni) are also considered. Highly hydrogenized specimens (under high pressure) appear to be stronger ferromagnetics

Synthesis of fast response crosslinked PVA-g-NIPAAm nanohydrogels by very low radiation dose in dilute aqueous solution

International Nuclear Information System (INIS)

Fathi, Marziyeh; Reza Farajollahi, Ali; Akbar Entezami, Ali

2013-01-01

Nanohydrogels of poly(vinyl alcohol)-g-N-isopropylacrylamide (PVA-g-NIPAAm) are synthesized by PVA and NIPAAm dilute aqueous solution using much less radiation dose of 1–20 Gy via intramolecular crosslinking at ambient temperature. The radiation synthesis of nanohydrogels is performed in the presence of tetrakis (hydroxymethyl) phosphonium chloride (THPC) due to its rapid oxygen scavenging abilities and hydrogen peroxide (H 2 O 2 ) as a source of hydroxyl radicals. The effect of radiation dose, feed composition ratio of PVA and H 2 O 2 is investigated on swelling properties such as temperature and pH dependence of equilibrium swelling ratio as well as deswelling kinetics. Experimental data exhibit high equilibrium swelling ratio and fast response time for the synthesized nanohydrogels. The average molecular weight between crosslinks (M c ) and crosslinking density (ρ x ) of the obtained nanohydrogels are calculated from swelling data as a function of radiation dose, H 2 O 2 and PVA amount. Fourier transform infrared spectroscopy (FT-IR), elemental analysis of nitrogen content and thermogravimetric analysis (TGA) are used to confirm the grafting reaction. Lower critical solution temperature (LCST) is measured around 33 °C by differential scanning calorimetry (DSC) for PVA-g-NIPAAm nanohydrogels. Dynamic light scattering (DLS) data demonstrate that the increase of radiation dose leads to the decreasing in dimension of nanohydrogels. Also, rheological studies are confirmed an improvement in the mechanical properties of the nanohydrogels with increasing the radiation dose. A cytotoxicity study exhibits a good biocompatibility for the obtained nanohydrogels. The prepared nanohydrogels show fast swelling/deswelling behavior, high swelling ratio, dual sensitivity and good cytocompatibility, which may find potential applications as biomaterial. - Highlights: ► A new radiation polymerization method is offered in dilute aqueous solution.► This method provides PVA

phase formation and thermal stability of fcc (fluorite) Ce1-xTbxO2-d solid solutions

NARCIS (Netherlands)

de Vries, Karel Jan; de Vries, K.J.; Meng, G.Y.

1998-01-01

Ce1−xTbxO2−δ solid solutions (x = 0.3, 0.4, and 0.5) were synthesized by a coprecipitation method, using ammonia. The formation process of the solid solutions was studied as a function of temperature up to 1200°C by X-ray diffraction, thermogravimetric analysis, and differential scanning

Effect of Heat Treatment on the Lithium Ion Conduction of the LiBH4–LiI Solid Solution

DEFF Research Database (Denmark)

Sveinbjörnsson, Dadi Þorsteinn; Mýrdal, Jón Steinar Garðarsson; Blanchard, Didier

2013-01-01

The LiBH4–LiI solid solution is a good Li+ conductor and a promising crystalline electrolyte for all-solid-state lithium based batteries. The focus of the present work is on the effect of heat treatment on the Li+ conduction. Solid solutions with a LiI content of 6.25–50% were synthesized by high...

Computationally efficient and quantitatively accurate multiscale simulation of solid-solution strengthening by ab initio calculation

Czech Academy of Sciences Publication Activity Database

Ma, D.; Friák, Martin; von Pezold, J.; Raabe, D.; Neugebauer, J.

2015-01-01

Roč. 85, FEB (2015), s. 53-66 ISSN 1359-6454 Institutional support: RVO:68081723 Keywords : Solid-solution strengthening * DFT * Peierls–Nabarro model * Ab initio * Al alloys Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 5.058, year: 2015

Local structure of Th1-xMO2 solid solutions (M = U, Pu)

International Nuclear Information System (INIS)

Hubert, S.; Heisbourg, G.; Moisy, Ph.; Dacheux, N.; Purans, J.E.

2004-01-01

X-ray absorption spectroscopy of Th 1-x U x O 2 and Th 1-x Pu x O 2 solid solutions was carried out on the Th, U L 3 -edges, and Pu L 3 edge to study the local structure environment of actinide mixed oxides. Various compositions of Th 1-x M x O 2 solid solutions have been prepared through the coprecipitation of the mixed oxalates from chloride or nitrate solutions: x = 0.11, 0.24, 0.37, 0.53, 0.67, 0.81, 0.91 and 1 for Th 1-x U x O 2 , and x = 0.13, 0.32, 0.66 and 1 for Th 1-x Pu x O 2 . They were characterized using X- ray diffraction. XRD analysis allowed to confirm that the variation of the lattice parameters varies linearly with the composition between the end members, suggesting that the atomic volume was conserved regardless of the details of the local distortions of the lattice, following the Vegard's law. Extending X-ray absorption fine structure (EXAFS) provides a direct characterization of the local distortions present in solid solutions. We found that opposite to the lattice parameter obtained by XRD, the interatomic distances given by EXAFS do not follow completely to neither the Vegard's law nor the virtual crystal approximation (VCA). However, the average lattice parameter obtained from EXAFS data for the first and the second shells agrees well with the one calculated from XRD data. (authors)

Solid solutions of platinum(II) and palladium(II) oxalato-complex salt as precursors of nanoalloys

Science.gov (United States)

Zadesenets, A. V.; Asanova, T. I.; Vikulova, E. S.; Filatov, E. Yu.; Plyusnin, P. E.; Baidina, I. A.; Asanov, I. P.; Korenev, S. V.

2013-03-01

A solid solution of platinum (II) and palladium (II) oxalato-complex salt, (NH4)2[Pt0.5Pd0.5(C2O4)2]·2H2O, has been synthesized and studied as a precursor for preparing bimetallic PtPd nanoparticles through its thermal decomposition. The smallest homogenous bimetallic PtPd nanoparticles were found to form in hydrogen and helium atmospheres. The annealing temperature and time have low effect on the bimetallic particles size. Comparative analysis of structural and thermal properties of the solid solution and individual Pt, Pd oxalato-complex salts was performed to investigate a mechanism of thermal decomposition of (NH4)2[Pt0.5Pd0.5(C2O4)2]·2H2O. Based on in situ X-ray photoemission spectroscopy investigation it was proposed a mechanism of formation of bimetallic PtPd nanoparticles from the solid-solution oxalato-complex salt during thermal decomposition.

The origin of ultrahigh piezoelectricity in relaxor-ferroelectric solid solution crystals

Energy Technology Data Exchange (ETDEWEB)

Li, Fei; Zhang, Shujun; Yang, Tiannan; Xu, Zhuo; Zhang, Nan; Liu, Gang; Wang, Jianjun; Wang, Jianli; Cheng, Zhenxiang; Ye, Zuo-Guang; Luo, Jun; Shrout, Thomas R.; Chen, Long-Qing (Penn); (Xian Jiaotong); (CIW); (Simon); (TRS Techn); (Wollongong)

2016-12-19

The discovery of ultrahigh piezoelectricity in relaxor-ferroelectric solid solution single crystals is a breakthrough in ferroelectric materials. A key signature of relaxor-ferroelectric solid solutions is the existence of polar nanoregions, a nanoscale inhomogeneity, that coexist with normal ferroelectric domains. Despite two decades of extensive studies, the contribution of polar nanoregions to the underlying piezoelectric properties of relaxor ferroelectrics has yet to be established. Here we quantitatively characterize the contribution of polar nanoregions to the dielectric/piezoelectric responses of relaxor-ferroelectric crystals using a combination of cryogenic experiments and phase-field simulations. The contribution of polar nanoregions to the room-temperature dielectric and piezoelectric properties is in the range of 50–80%. A mesoscale mechanism is proposed to reveal the origin of the high piezoelectricity in relaxor ferroelectrics, where the polar nanoregions aligned in a ferroelectric matrix can facilitate polarization rotation. This mechanism emphasizes the critical role of local structure on the macroscopic properties of ferroelectric materials.

The origin of ultrahigh piezoelectricity in relaxor-ferroelectric solid solution crystals.

Science.gov (United States)

Li, Fei; Zhang, Shujun; Yang, Tiannan; Xu, Zhuo; Zhang, Nan; Liu, Gang; Wang, Jianjun; Wang, Jianli; Cheng, Zhenxiang; Ye, Zuo-Guang; Luo, Jun; Shrout, Thomas R; Chen, Long-Qing

2016-12-19

The discovery of ultrahigh piezoelectricity in relaxor-ferroelectric solid solution single crystals is a breakthrough in ferroelectric materials. A key signature of relaxor-ferroelectric solid solutions is the existence of polar nanoregions, a nanoscale inhomogeneity, that coexist with normal ferroelectric domains. Despite two decades of extensive studies, the contribution of polar nanoregions to the underlying piezoelectric properties of relaxor ferroelectrics has yet to be established. Here we quantitatively characterize the contribution of polar nanoregions to the dielectric/piezoelectric responses of relaxor-ferroelectric crystals using a combination of cryogenic experiments and phase-field simulations. The contribution of polar nanoregions to the room-temperature dielectric and piezoelectric properties is in the range of 50-80%. A mesoscale mechanism is proposed to reveal the origin of the high piezoelectricity in relaxor ferroelectrics, where the polar nanoregions aligned in a ferroelectric matrix can facilitate polarization rotation. This mechanism emphasizes the critical role of local structure on the macroscopic properties of ferroelectric materials.

Interaction of photons with some solutions

International Nuclear Information System (INIS)

Singh, Kulwant; Gagandeep; Lark, B.S.; Sahota, H.S.

2000-01-01

With the advancement and applicability of gamma attenuation coefficients in a variety of applications, accurate data on narrow beam attenuation coefficients are required. In order to make use of the fact that scattering and absorption of gamma radiations are related to the density and effective atomic number of the material, a knowledge of the mass attenuation coefficients, μ/ρ is of prime importance. Hubbell and Seltzer have compiled the mass attenuation coefficients for a large number of compounds and mixtures of dosimetric and biological importance. The previous studies for the determination of attenuation coefficients have been concerned with crystalline samples in the solid form. In the pioneer work, Teli et al. have determined the gamma ray attenuation coefficients in dilute solutions of some salts. Gerward determined linear and mass attenuation coefficients in the general case as well as in the limit of extreme dilution. Recently Singh et al., measured attenuation coefficients of some solutes in water at different concentrations. The present study covers the study of attenuation coefficients of 1:1 and 1:2 electrolytes of some chlorides and sulphates in energy regions in which the influence of all photon processes can be seen and the investigation is expected to yield valuable information. (author)

Alloying Solid Solution Strengthening of Fe-Ga Alloys: A First-Principle Study

National Research Council Canada - National Science Library

Chen, Kuiying; Cheng, Leon M

2006-01-01

... and Co in cubic solid solution of Fe-Ga alloys. Mayer bond order "BO" values were used to evaluate the atomic bond strengths in the alloys, and were then used to assess the alloying strengthening characteristics...

Large-scale fluctuations in the diffusive decomposition of solid solutions

International Nuclear Information System (INIS)

Karpov, V.G.; Grimsditch, M.

1995-01-01

The concept of an instability in the classic Ostwald ripening theory with respect to compositional fluctuations is suggested. We show that small statistical fluctuations in the precipitate phase lead to gigantic Coulomb-like fluctuations in the solute concentration which in turn affect the ripening. As a result large-scale fluctuations in both the precipitate and solute concentrations appear. These fluctuations are characterized by amplitudes of the order of the average values of the corresponding quantities and by a space scale L∼(na) -1/2 which is considerably greater than both the average nuclear radius and internuclear distance. The Lifshitz-Slyozov theory of ripening is shown to remain locally applicable, over length scales much less than L. The implications of these findings for elastic light scattering in solid solutions that have undergone Ostwald ripening are considered

Large-scale fluctuations in the diffusive decomposition of solid solutions

Science.gov (United States)

Karpov, V. G.; Grimsditch, M.

1995-04-01

The concept of an instability in the classic Ostwald ripening theory with respect to compositional fluctuations is suggested. We show that small statistical fluctuations in the precipitate phase lead to gigantic Coulomb-like fluctuations in the solute concentration which in turn affect the ripening. As a result large-scale fluctuations in both the precipitate and solute concentrations appear. These fluctuations are characterized by amplitudes of the order of the average values of the corresponding quantities and by a space scale L~(na)-1/2 which is considerably greater than both the average nuclear radius and internuclear distance. The Lifshitz-Slyozov theory of ripening is shown to remain locally applicable, over length scales much less than L. The implications of these findings for elastic light scattering in solid solutions that have undergone Ostwald ripening are considered.

Sugar yields from dilute oxalic acid pretreatment of maple wood compared to those with other dilute acids and hot water.

Science.gov (United States)

Zhang, Taiying; Kumar, Rajeev; Wyman, Charles E

2013-01-30

Dilute oxalic acid pretreatment was applied to maple wood to improve compatibility with downstream operations, and its performance in pretreatment and subsequent enzymatic hydrolysis was compared to results for hydrothermal and dilute hydrochloric and sulfuric acid pretreatments. The highest total xylose yield of ∼84% of the theoretical maximum was for both 0.5% oxalic and sulfuric acid pretreatment at 160 °C, compared to ∼81% yield for hydrothermal pretreatment at 200 °C and for 0.5% hydrochloric acid pretreatment at 140 °C. The xylooligomer fraction from dilute oxalic acid pretreatment was only 6.3% of the total xylose in solution, similar to results with dilute hydrochloric and sulfuric acids but much lower than the ∼70% value for hydrothermal pretreatment. Combining any of the four pretreatments with enzymatic hydrolysis with 60 FPU cellulase/g of glucan plus xylan in the pretreated maple wood resulted in virtually the same total glucose plus xylose yields of ∼85% of the maximum possible. Copyright © 2012 Elsevier Ltd. All rights reserved.

Contribution of Lattice Distortion to Solid Solution Strengthening in a Series of Refractory High Entropy Alloys

Science.gov (United States)

Chen, H.; Kauffmann, A.; Laube, S.; Choi, I.-C.; Schwaiger, R.; Huang, Y.; Lichtenberg, K.; Müller, F.; Gorr, B.; Christ, H.-J.; Heilmaier, M.

2018-03-01

We present an experimental approach for revealing the impact of lattice distortion on solid solution strengthening in a series of body-centered-cubic (bcc) Al-containing, refractory high entropy alloys (HEAs) from the Nb-Mo-Cr-Ti-Al system. By systematically varying the Nb and Cr content, a wide range of atomic size difference as a common measure for the lattice distortion was obtained. Single-phase, bcc solid solutions were achieved by arc melting and homogenization as well as verified by means of scanning electron microscopy and X-ray diffraction. The atomic radii of the alloying elements for determination of atomic size difference were recalculated on the basis of the mean atomic radii in and the chemical compositions of the solid solutions. Microhardness (μH) at room temperature correlates well with the deduced atomic size difference. Nevertheless, the mechanisms of microscopic slip lead to pronounced temperature dependence of mechanical strength. In order to account for this particular feature, we present a combined approach, using μH, nanoindentation, and compression tests. The athermal proportion to the yield stress of the investigated equimolar alloys is revealed. These parameters support the universality of this aforementioned correlation. Hence, the pertinence of lattice distortion for solid solution strengthening in bcc HEAs is proven.

Activity coefficients at infinite dilution and physicochemical properties for organic solutes and water in the ionic liquid 4-(2-methoxyethyl)-4-methylmorpholinium trifluorotris(perfluoroethyl)phosphate

International Nuclear Information System (INIS)

Wlazło, Michał; Marciniak, Andrzej

2012-01-01

Highlights: ► The γ 13 ∞ and K L for 62 solutes in the IL [COC 2 mMOR][FAP] were determined by IGC. ► Partial molar excess thermodynamic functions at infinite dilution were calculated. ► The selectivities and capacities for selected separation problems were calculated. ► LFER system constants as a function of T for [COC 2 mMOR][FAP] were calculated. - Abstract: This paper presents new data on activity coefficients at infinite dilution, γ ∞ for 62 different solutes: alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, alcohols, thiophene, ethers, ketones, and water in the ionic liquid 4-(2-methoxyethyl)-4-methylmorpholinium trifluorotris(perfluoroethyl)phosphate, [COC 2 mMOR][FAP]. The data were determined by inverse gas chromatography at six temperatures from T = 318.15 K to T = 368.15 K. These values were compared with ionic liquid based on the same cation and bis(trifluoromethylsulfonyl)-amide anion, [COC 2 mMOR][NTf 2 ]. Additionally the partial molar excess Gibbs free energies ΔG 1 E,∞ , enthalpies ΔH 1 E,∞ , and entropies ΔS 1 E,∞ at infinite dilution were calculated from the experimental γ ∞ values obtained over the temperatures range. The selectivities and capacities at infinite dilution for hexane/benzene, cyclohexane/benzene, and heptane/thiophene extraction problems were calculated from the γ ∞ to verify the possibility of investigated ionic liquid as an entrainer in liquid–liquid extraction and desulphurization of fuels. Obtained values were compared with literature data of other ionic liquids based on trifluorotris(perfluoroethyl)phosphate and bis(trifluoromethylsulfonyl)-amide anions and industrial solvents: NMP and sulfolane. Also the Abraham solvation parameter model was used for evaluation of the solvation characteristic of the ionic liquid. Linear free energy relationship (LFER) system constants as a function of temperature were calculated.

Decomposition features of a supersaturated solid solution in the Mg-3.3 wt. % Yb alloy

International Nuclear Information System (INIS)

Dobromyslov, A.V.; Kajgorodova, L.I.; Sukhanov, V.D.; Dobatkina, T.V.

2007-01-01

Methods of electron microscopy, hardness measuring and X-ray diffraction analysis are applied to study decomposition kinetics for a supersaturated solid solution in a Mg-3.3 mas. % alloy on aging within a temperature range of 150-225 deg C. The mechanism of supersaturation solid solution decomposition is revealed along with the nature of phases precipitated at various stages of aging: on incomplete and extended aging as well as at maximum hardness. The types of structural constituents responsible for changes of hardness on aging are determined [ru

Muonated cyclohexadienyl radicals observed by level crossing resonance in dilute solutions of benzene in hexane subjected to muon-irradiation

International Nuclear Information System (INIS)

Walker, D.C.; Barnabas, M.V.; Venkateswaran, K.

1988-11-01

Benzene is used here as a scavenger of muonium to produce the muonated cyclohexadienyl radical in dilute solutions in n-hexane. The radical was identified by level crossing resonance spectroscopy (LCR) by observing the proton resonance of the -CHMu group occurring at 2.059T. Its yield is found to equal the sum of the muonium atom yield and the 'missing' muon yield in hexane (total 35% of the incident muons). Consequently, the complete dispersement of muons in different chemical associations is now accounted for in a saturated hydrocarbon liquid, and is seen to be similar to that in water

Recovery of Cu(II from diluted aqueous solutions by non-dispersive solvent extraction

Directory of Open Access Journals (Sweden)

Alguacil, E. J.

2002-08-01

Full Text Available The removal of copper from diluted aqueous solutions with ACORGA M5640 extractant using non-dispersive solvent extraction technology was studied. It was possible to remove Cu(II below the international standars from solutions having initially as low concentration as 0,01 g/l under various experimental conditions, i.e aqueous pH 4.0, 10 % v/v ACORGA M5640 in Exxol D100, an organic flow of 100 ml/min, and an aqueous flow 50ml/min. Since the removal occurs by chelating ion exchange between copper from solution and protons from the extractant, the former was stripped by using a 180 g/l sulphuric acid solution which flowed (50 ml/min through the tube side organic was passed (400 ml/min through the shell side of the fibers of the module

Se estudia la eliminación del cobre presente en disoluciones acuosas diluidas empleando el agente de extracción ACORGA M5640 y la tecnología de extracción con disolventes no dispersiva. Bajo las condiciones experimentales estudiadas, pH de la fase acuosa 4,0 ±0,1, 10 % v/v ACORGA M5640 en Exxsol D100, flujo de la fase orgánica 100 ml/min, flujo de la fase acuosa 50 ml/min, es posible eliminar el Cu(II, por debajo de los límites marcados internacionalmente, en disoluciones con un contenido tan bajo como 0,01 g/1 del metal. Debido a que la extracción transcurre mediante un intercambio catiónico (y formación de un compuesto tipo quelato entre el cobre presente en el medio acuoso y los protones del agente de extracción, el metal se puede reextraer mediante la utilización de una disolución de 180 g/1 de ácido sulfúrico que fluye (50 ml/min a través de la parte interior de las fibras del módulo, mientras que la fase orgánica fluye (400 ml/min por la parte exterior de las mismas fibras.

Composite systems of dilute and dense couplings

International Nuclear Information System (INIS)

Raymond, J R; Saad, D

2008-01-01

Composite systems, where couplings are of two types, a combination of strong dilute and weak dense couplings of Ising spins, are examined through the replica method. The dilute and dense parts are considered to have independent canonical disordered or uniform bond distributions; mixing the models by variation of a parameter γ alongside inverse temperature β we analyse the respective thermodynamic solutions. We describe the variation in high temperature transitions as mixing occurs; in the vicinity of these transitions we exactly analyse the competing effects of the dense and sparse models. By using the replica symmetric ansatz and population dynamics we described the low temperature behaviour of mixed systems

MANAGEMENT OF SOLID WASTE GENERATED BY THE INTEGRATED STEELWORKS ACTIVITY AND SOLUTIONS TO REDUCE THE ENVIRONMENTAL IMPACT

Directory of Open Access Journals (Sweden)

Anişoara CIOCAN

2010-05-01

Full Text Available The development of steel industry is subject to solve major problems arising from industry-nature relationship, strictly targeted on pollution control and protection of natural resources and energy. In this paper we discussed about the management of solid waste generated by an integrated steelwork located near a major urban area and the adopted solutions for the reduction of environmental impact. There are summarized technical solutions that are currently applied and were proposed some solutions that can be applied in accordance with the environmental legislations. The new solutions are proposed for integrated management of solid wastes in accordance with: the exact quantification (quantitative, qualitative and the generation sources of emissions and solid wastes; controlled storage; minimization of the wastes and its harmfulness; transformation of the wastes into valuable by-products used directly by the company in a subsequent process, or by external down-stream user.

Activity coefficients at infinite dilution measurements for organic solutes in the ionic liquid 1-hexyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)-imide using g.l.c. at T=(298.15, 313.15, and 333.15) K

International Nuclear Information System (INIS)

Letcher, Trevor M.; Marciniak, Andrzej; Marciniak, MaIgorzata; Domanska, Urszula

2005-01-01

The activity coefficients at infinite dilution, γ 13 ∞ (where 1 refers to the solute and 3 to the solvent), for both polar and non-polar solutes (alkanes, alk-1-enes, alk-1-ynes, cycloalkanes, benzene, carbon tetrachloride, and methanol) in the ionic liquid 1-hexyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)-imide [HMIM][Tf 2 N] at three temperatures T=(298.15, 313.15, and 333.15) K have been determined by gas-liquid chromatography. The interaction at the gas-liquid interface between the solutes and the solvent was examined by varying solvent liquid loading on the column. Corrected retention values, taking carrier gas and solute imperfections into account, were determined and used to calculate the activity coefficients at infinite dilution. The results have been used to predict the solvent potential for the hexane/benzene separation from calculated selectivity values. The results were compared to γ 13 ∞ for similar systems found in the literature in an attempt to understand the effect of the nature of the cation and anion has on solute-solvent interactions. The partial molar excess enthalpies at infinite dilution values ΔH 1 E∞ were calculated from the experimental γ 13 ∞ values obtained over the temperature range

The Effect of Dilution on Microsegregation in AWS ER NiCrMo-14 Alloy Welding Claddings

Science.gov (United States)

Miná, Émerson Mendonça; da Silva, Yuri Cruz; Dille, Jean; Silva, Cleiton Carvalho

2016-12-01

Dilution and microsegregation are phenomena inherent to claddings, which, in turn, directly affect their main properties. This study evaluated microsegregation in the fusion zone with different dilution levels. The overlays were welded by the TIG cold wire feed process. Dilution was calculated from the geometric characteristics of the claddings and from the conservation of mass equation using chemical composition measurements. Microsegregation was calculated using energy dispersive X-ray spectroscopy measurements of the dendrites and the chemical composition of the fusion zone. The dilution of the claddings was increased by reducing the wire feed rate. Fe showed potential to be incorporated into the solid phase ( k > 1), and this increased with the increase of dilution. Mo, in turn, was segregated into the liquid phase ( k < 1) and also increased with the increase of dilution. However, Cr and W showed a slight decrease in their partition coefficients ( k) with the increase of dilution.

Activity coefficients at infinite dilution and physicochemical properties for organic solutes and water in the ionic liquid 1-(2-hydroxyethyl)-3-methylimidazolium trifluorotris(perfluoroethyl)phosphate

International Nuclear Information System (INIS)

Marciniak, Andrzej; Wlazło, Michał

2013-01-01

Highlights: • γ ∞ and K L for 65 solutes in the IL [C 2 OHmim][FAP] were determined by IGC. • Partial molar thermodynamics functions ΔG 1 E,∞ , ΔH 1 E,∞ and ΔS 1 E,∞ were calculated. • Selectivities and capacities for alkanes/thiophene separation problems were calculated. • LFER system constants as a function of T for [C 2 OHmim][FAP] were calculated. • Results were compared to other ILs based on the same cation and anion. -- Abstract: This work presents new data of activity coefficients at infinite dilution, γ ∞ of different organic solutes and water in the 1-(2-hydroxyethyl)-3-methylimidazolium trifluorotris(perfluoroethyl)phosphate, [C 2 OHmim][FAP] ionic liquid. Values of γ ∞ were determined for 65 organic solutes, including alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, alcohols, thiophene, ethers, ketones, esters, 1-nitropropane, aldehydes, acetonitrile and water by inverse gas chromatography within the temperature range from (318.15 to 368.15) K. The basic thermodynamic functions, such as partial molar excess Gibbs energies, ΔG 1 E,∞ , enthalpies, ΔH 1 E,∞ and entropies, ΔS 1 E,∞ at infinite dilution were calculated from the experimental γ ∞ values obtained over the temperature range. Additionally the gas–liquid partition coefficients, K L were determined. Experimental values of gas–liquid partition coefficients were used to determine the coefficients in the Abraham solvation parameter model (LFER). Results are compared to previously investigated ionic liquids with the same [C 2 OHmim] + cation and [FAP] − anion. The selectivity and capacity at infinite dilution for alkanes/thiophene extraction problems were calculated from experimental γ ∞ values to verify the possibility of investigated ionic liquid as an entrainer in liquid–liquid extraction

Specific features of kinetics of He3-He4 solid solution transformations at superlow temperatures

International Nuclear Information System (INIS)

Mikheev, V.A.; Majdanov, V.A.; Mikhin, N.P.

1986-01-01

The NMR data on the phase transition kinetics of 3 He- 4 He solid solutions at T=100 mK are considered. Studied are solid helium samples of a molecular volume of 20.55 cm 2 /mol with a 3 He content of 0.54 %. An unusually long phase transition time is found which is dependent on the prehistory of sample. The spin diffusion of 3 He in the transformated solution concentrated phase is found to be of a quasi-one-dimensional nature with the diffusion coefficient value typical of liquid

Solid solutions on the base of CuCr2Se4 and CUsUb(1/2)Insub(1/2)Crsub(2)Sesub(4)

International Nuclear Information System (INIS)

Smirnov, S.G.; Rozantsev, A.V.; Kesler, Ya.A.; Gordeev, I.V.; Tret'yakov, Yu.D.

1983-01-01

The CuCr 2 Se 4 interaction with Cusub(1/2)Insub(1/2)Crsub(2)Sesub(4) for determining the fields of solid solutions existence and studying their crystallochemical properties is investigated. Solid solutions of the (1-x)Cusub(1/2)Insub(1/2)Crsub(2)Sesub(4)xxCuCrsub(2)Sesub(4) are prepared, two limited regions of solid solutions of spinel type at 0 <= x <= 0.2 and 0.8 <= x <= 1 are determined. X-ray radiography investigation of synthesized solid solutions is carried out. It has been found that at 0 <= x <= 0.2 solid solutions are crystallized in the ordered spinel structure F anti 43m

Solubility behaviour of antimony(III) and antimony(V) solids in basic aqueous solutions at 300oC

International Nuclear Information System (INIS)

Lemire, R.J.; Tosello, N.B.; Halliday, J.D.

1999-12-01

The major contributions of the isotopes 122 Sb and 124 Sb to activity transport in a CANDU reactor primary heat transport system (HTS), have been associated with oxygen ingress during reactor shutdown. As part of a program to minimize the release and redeposition of these isotopes, the solubilities of antimony(III) and (V) oxides and salts have been measured in basic solutions at temperatures from 25 to 300 o C. The results provide information on the charge and the stability as a function of temperature of antimony solution species and, hence, a guide to the trends in the temperature dependence of the solubilities of antimony solids. In solutions in which oxidation of antimony(III) to antimony(V) is minimized, the solubility of Sb 2 O 3 increases by about two orders of magnitude between 25 and 200 o C, and then levels out or decreases slightly. At 250 o C, in oxidizing solutions, Sb 2 O 5 ·xH 2 O and simple sodium antimonate(V) were found to be unstable in sodium hydroxide solutions with respect to the solid, Na 2α [H(H 2 O)] 2-2α Sb 2 O 6 , which has a pyrochlore structure. The solubility of this partially protonated sodium antimonate increases from 25 to 200 o C and decreases at temperatures above 250 o C. These solubility changes for the antimony (V) solids reflect changes in the stability of the anionic antimony solution species (SbO 3 - or Sb(OH) 6 - ), even though the compositions of antimony-containing solids in basic oxidizing solutions are strongly dependent on the cations and their aqueous phase concentrations. All solids used in the present experiments would be expected to generate total solution antimony concentrations ≥ 0.00005 mol·dm -3 in any neutral or basic aqueous solutions (assuming no added sodium salts). Therefore, under HTS conditions, precipitation of any antimony oxides or mixed oxides is unlikely. It cannot be ruled out that hydrated Sb 2 O 5 (especially the pyrochlore form) might be less soluble in near-neutral, low

Sequestration of chromium by exopolysaccharides of Nostoc and Gloeocapsa from dilute aqueous solutions

Energy Technology Data Exchange (ETDEWEB)

Sharma, Mona [Department of Environmental Science and Engineering, Guru Jambheshwar University of Science and Technology, Hisar-125 001 (India); Kaushik, Anubha [Department of Environmental Science and Engineering, Guru Jambheshwar University of Science and Technology, Hisar-125 001 (India)], E-mail: aks_10@yahoo.com; Somvir,; Bala, Kiran; Kamra, Anjana [Department of Environmental Science and Engineering, Guru Jambheshwar University of Science and Technology, Hisar-125 001 (India)

2008-09-15

This article reports the chromium removal potential of exopolysaccharides (EPS) of two indigenously isolated cyanobacterial strains, Gloeocapsa calcarea and Nostoc punctiforme. The biosorption was studied by varying pH from 2 to 6 and initial chromium concentration from 5 to 20 mg/L to find out the optimized conditions for maximum chromium removal by EPS. Two equilibrium models, Langmuir and Freundlich, were used to explain these results. The Freundlich model was found to be better applicable to the experimental data as compared to Langmuir as inferred from high value of coefficient of determination whereas the optimal conditions were found to be same for the two (pH 2 and initial chromium concentration 20 mg/L). EPS production by the two strains was also studied which was found to be higher for Gloeocapsa. On the basis of experimental results and model parameters, it can be inferred that the EPS extracted from Nostoc has comparatively high biosorption capacity and can be utilized for the removal of chromium from dilute aqueous solution. Adsorption of chromium on EPS was further confirmed by surface morphology observed in scanning electron micrographs.

Sequestration of chromium by exopolysaccharides of Nostoc and Gloeocapsa from dilute aqueous solutions

International Nuclear Information System (INIS)

Sharma, Mona; Kaushik, Anubha; Somvir,; Bala, Kiran; Kamra, Anjana

2008-01-01

This article reports the chromium removal potential of exopolysaccharides (EPS) of two indigenously isolated cyanobacterial strains, Gloeocapsa calcarea and Nostoc punctiforme. The biosorption was studied by varying pH from 2 to 6 and initial chromium concentration from 5 to 20 mg/L to find out the optimized conditions for maximum chromium removal by EPS. Two equilibrium models, Langmuir and Freundlich, were used to explain these results. The Freundlich model was found to be better applicable to the experimental data as compared to Langmuir as inferred from high value of coefficient of determination whereas the optimal conditions were found to be same for the two (pH 2 and initial chromium concentration 20 mg/L). EPS production by the two strains was also studied which was found to be higher for Gloeocapsa. On the basis of experimental results and model parameters, it can be inferred that the EPS extracted from Nostoc has comparatively high biosorption capacity and can be utilized for the removal of chromium from dilute aqueous solution. Adsorption of chromium on EPS was further confirmed by surface morphology observed in scanning electron micrographs

Impact of vacancy-solute clusters on the aging of α-Fe solid solutions

International Nuclear Information System (INIS)

Schuler, Thomas

2015-01-01

Understanding and monitoring the aging of steels under vacancy supersaturation is a challenge of great practical interest for many industrial groups, and most of all for those related to nuclear energy. These steels always contain interstitial solutes, either as alloying elements or as impurities, and vacancies (V) that are equilibrium structural defects of materials. We have chosen the Fe-V -X system (X = C, N or O) as a model system for ferritic steels. Vacancy-solute clusters are likely to form in such systems because, despite the very low concentrations of their components, these cluster show very high attractive bonding. First of all, we have been working on the computation of intrinsic equilibrium properties of individual clusters, both thermodynamic (free binding energies) and kinetic (mobilities, dissociation coefficients, and their relationship with continuum diffusion) properties. Thanks to this atomic-scale characterization procedure, we have been able to highlight various effects of these clusters on a macroscopic system containing different cluster types: increase of solute solubility limits and total vacancy concentrations, flux couplings between interstitial solutes and vacancies, acceleration of solute precipitation kinetics and precipitate dissolution by solid solution stabilization due to vacancies. These results would not have been obtained without the development and/or extension of analytical methods in statistical physics which are able to describe cluster's components and their interactions at the atomic scale. Finally, we have also been working on cavities in α-iron, the study of which requires a different approach. Our study highlights the impact of the atomic discrete lattice on the equilibrium shape of cavities, and describes various kinetic mechanisms of these objects at the atomic scale. (author) [fr

Bulk diffusion and solubility of silver and nickel in lead, lead-silver and lead-nickel solid solutions

International Nuclear Information System (INIS)

Amenzou-Badrour, H.; Moya, G.; Bernardini, J.

1988-01-01

The results of a study of solubility and bulk diffusion of /sup 110/Ag and /sup 63/Ni in lead, lead-silver and lead-nickel solid solutions in the temperature range 220 to 88 0 C are reported. Owing to the low solubility of silver and nickel in lead, Fick's solution corresponding to the boundary condition of a constant concentration of solute at the surface has been used. Depth profile concentration analysis suggests a fundamental difference between the diffusion mechanisms of silver and nickel. Since silver penetration profiles in pure lead give diffusion coefficients independent of the penetration depth and silver concentration, it is suggested that slight decreases of silver diffusivity in lead-silver solid solutions have no significance. This implies that the interstitial silver atoms do not associate significantly with each other to form Ag-Ag dimers. In contrast, different behaviors of /sup 63/Ni depth profile concentration in pure lead and saturated PbNi solid solutions agree with a Ni-Ni interaction leading to the formation of less mobile dimers near the surface in pure lead

Investigation of water and saline solution drops evaporation on a solid substrate

Directory of Open Access Journals (Sweden)

Orlova Evgenija G.

2014-01-01

Full Text Available Experimental investigation water and saline solution drops evaporation on a solid substrate made of anodized aluminum is presented in the paper. Parameters characterizing drop profile have been obtained (contact angle, contact diameter, height. The specific evaporation rate has been calculated from obtained values. It was found that water and saline solution drops with concentration up to 9.1% evaporate in the pinning mode. However, with increasing the salt concentration in the solution up to 16.7% spreading mode was observed. Two stages of drop evaporation depending on change of the evaporation rate have been separated.

Formation of solid solution during mutual diffusion of tungsten and molybdenum in the process of sintering

International Nuclear Information System (INIS)

Timofeeva, A.A.; Bulat, I.B.; Voronin, Yu.V.; Fedoseev, G.K.; Karasev, V.M.

1984-01-01

A process of a solid solution homogenization during sintering of W-15Mo and W-5Mo alloys is studied by the methods of density measurements, analysis of the X-ray lines physical broadening and determination of crystalline lattice constant. Study of the process of solid solution formation under conditions of powder composite sintering is shown to be conducted with account of peculiarities of tungsten and molybdenum mutual diffusion in the investigated temperature range of concentrations

Study on the enthalpy of solution and enthalpy of dilution for the ionic liquid [C3mim][Val] (1-propyl-3-methylimidazolium valine)

International Nuclear Information System (INIS)

Guan Wei; Li Long; Ma Xiaoxue; Tong Jing; Fang Dawei; Yang Jiazhen

2012-01-01

Graphical abstract: The thermodynamic cycle for estimation of the hydration enthalpy of ionic liquid [C 3 mim][Val]. Highlights: ► A new amino acid ionic liquid [C 3 mim][Val] was prepared. ► The molar enthalpies of solution of the ionic liquid. ► The hydration enthalpy of the cation [C 3 mim] + was estimated. ► The molar enthalpies of dilution, of aqueous [C 3 mim][Val] were measured. - Abstract: A new amino acid ionic liquid (AAIL) [C 3 mim][Val] (1-propyl-3-methylimidazolium valine) was prepared by the neutralization method. Using the solution-reaction isoperibol calorimeter, molar solution enthalpies of the ionic liquid [C 3 mim][Val] with known amounts of water and with different concentrations in molality were measured at T = 298.15 K. In terms of standard addition method (SAM) and Archer’s method, the standard molar enthalpy of solution for [C 3 mim][Val] without water, Δ s H m ∘ = (−55.7 ± 0.4) kJ · mol −1 , was obtained. The hydration enthalpy of the cation [C 3 mim] + , ΔH + ([C 3 mim] + ) = −226 kJ · mol −1 , was estimated in terms of Glasser’s theory. Using the RD496-III heat conduction microcalorimeter, the molar enthalpies of dilution, Δ D H m (m i → m f ), of aqueous [C 3 mim][Val] with various values of molality were measured. The values of Δ D H m (m i → m f ) were fitted to Pitzer’s ion-interaction model and the values of apparent relative molar enthalpy, φ L, calculated using Pitzer’s ion-interaction model.

Decomposition of supersaturated solid solutions Mg-Ho and Mg-Gd

International Nuclear Information System (INIS)

Sukhanov, V.D.; Dobromyslov, A.V.; Rokhlin, L.L.; Dobatkina, T.V.

2002-01-01

Methods of electron microscopy and X-ray diffraction analysis are applied to study ageing magnesium base alloys with holmium and gadolinium. It is shown that the precipitation of supersaturated Mg base solid solutions goes through several subsequent stages and is accompanied by a considerable precipitation hardening effect at the stage of metastable phase precipitation. The influence of aging time and temperature on precipitation kinetics is established [ru

Photocatalytic hydrogen production over solid solutions between BiFeO{sub 3} and SrTiO{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Lu, Lingwei; Lv, Meilin [Shanghai Key Lab of Chemical Assessment and Sustainability, Department of Chemistry, Tongji University, 1239 Siping Road, Shanghai, 200092 (China); Liu, Gang [Shenyang National laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Science, 72 Wenhua Road, Shenyang 110016 (China); Xu, Xiaoxiang, E-mail: xxxu@tongji.edu.cn [Shanghai Key Lab of Chemical Assessment and Sustainability, Department of Chemistry, Tongji University, 1239 Siping Road, Shanghai, 200092 (China)

2017-01-01

Graphical abstract: We have successfully prepared a series of SrTiO{sub 3}-BiFeO{sub 3} solid solutions. These materials own strong visible light absorption and demonstrate appealing photocatalytic activity under both full range and visible light irradiation. - Highlights: • Band gap values can be tuned by adjusting molar ratios between SrTiO{sub 3} and BiFeO{sub 3}. • Photocatalytic activity is greatly improved after constituting solid solutions. • Photocatalytic activity is influenced by surface area and light absorption. • Fe plays an important role for band gap reduction and catalytic activity. - Abstract: Constituting solid solutions has been an appealing means to gain control over various physicochemical properties. In this work, we synthesized a series of SrTiO{sub 3}-BiFeO{sub 3} solid solutions and systematically explored their structural, optical and photocatalytic properties. Our results show that all solid solutions crystallize in a primitive cubic structure and their band gap values can be easily tuned by adjusting molar ratios between SrTiO{sub 3} and BiFeO{sub 3}. Photocatalytic hydrogen production under both full range and visible light irradiation is greatly improved after forming solid solutions. The highest hydrogen production rate obtained is ∼180 μmol/h under full range irradiation (λ ≥ 250 nm) and ∼4.2 μmol/h under visible light irradiation (λ ≥ 400 nm), corresponding to apparent quantum efficiency ∼2.28% and ∼0.10%, respectively. The activity is found to be strongly influenced by surface area and light absorption. Theoretical calculation suggests that Fe contributes to the formation of spin-polarized bands in the middle of original band gap and is responsible for the band gap reduction and visible light photocatalytic activity.

Measurement of Activity Coefficients at Infinite Dilution for Alcohols in [BMIM][CH3SO4] using HS-SPME/GC-FID

Directory of Open Access Journals (Sweden)

A. M. Elias

Full Text Available ABSTRACT The activity coefficient at infinite dilution (&IN1 and distribution ratios at infinite dilution (&IN2 were determined for alkanols (methanol, ethanol, 1-propanol, 1-butanol, 2-butanol, and 2-methyl-2-propanol in the ionic liquid (IL 1-butyl-3-methylimidazolium methyl sulfate ([BMIM][CH3SO4] by HS-SPME (Headspace - Solid Phase Micro Extraction at four temperatures (298.15, 313.15, 333.15, and 353.15K using headspace - solid phase microextraction (SPME-HS. The results showed significant agreement with literature data. In addition, partial molar excess enthalpies at infinite dilution (&IN3, excess Gibbs energies (&IN4, and excess entropies (&IN5 were calculated from the (&IN6 values.

Crystal-chemical features of the solid solutions

Energy Technology Data Exchange (ETDEWEB)

Titov, V.V.; Kesler, Ya.A.; Gordeev, I.V.; Mozhaev, A.P.

1988-04-01

The unusual magnetic properties of the solid solutions of CuCr/sub 2/S/sub 4/ in Cu/sub 0.5/Mo/sub 0.5/Cr/sub 2/S/sub 4/ (M = Al, Ga, In) are closely related to the crystal chemistry of these compounds. Specimens for structural investigation were obtained by solid-phase synthesis in evacuated quartz capsules. X-ray phase analysis of all the compounds was made by the powder method in a DRON-1 diffractometer with Cu K..cap alpha.. filtered radiation. The experimental confirmation of the ordering of the cations in the tetrahedral sublattice of the investigated spinels was obtained by the authors from their IR absorption spectra taken in the range 400-33 cm/sup /minus/1/. The presence of seven intense absorption bands in the spectra of the specimens indicates that these materials belong to the space group F/anti/43m, i.e., that there is ordering in the A sublattice. Their investigation led them to the conclusion that in a number of cases the vibrational spectra of the crystals are more sensitive in the investigation of atomic ordering than the spectra of x-ray and neutron diffraction, in agreement with the theoretical predictions.

Activity coefficients at infinite dilution of organic solutes in the ionic liquid trihexyltetradecylphosphonium bis (trifluoromethylsulfonyl) imide using gas–liquid chromatography at T = (313.15, 333.15, 353.15 and 373.15) K

International Nuclear Information System (INIS)

Tumba, Kaniki; Letcher, Trevor M.; Naidoo, Paramespri; Ramjugernath, Deresh

2013-01-01

Highlights: • Activity coefficients at infinite dilution measured in the ionic liquid [3C 6 C 14 P][BTI]. • 22 solutes investigated at T = (313.15, 333.15, 353.15, 373.15) K using glc. • Selectivities and capacities for selected separations compared to other IL’s and solvents. -- Abstract: Activity coefficients at infinite dilution for organic solutes, which include n-alkanes, alk-1-enes, alk-1-ynes, cycloalkanes, alkylbenzenes, alcohols and ketones, in the ionic liquid trihexyltetradecylphosphonium bis (trifluoromethylsulfonyl) imide were measured by gas–liquid chromatography using the latter as the stationary phase. This ionic liquid had previously been studied and reported in literature; however due to significant discrepancies in the reported infinite activity coefficient values, there was justification for further study and reporting. The temperature range investigated in this study is significantly wider and at higher temperatures than presented previously in the literature. From the experimental infinite dilution activity coefficient data at the four different temperatures T = (313.15, 333.15, 353.15 and 373.15) K, partial molar excess enthalpies at infinite dilution were calculated. Values of the selectivity for hexane/benzene and methanol/benzene separations were determined from experimental values of the activity coefficients at infinite dilution and these results were compared to literature values for other ionic liquids, as well as for industrial solvents. The capacities were also determined as it gives an indication of the solvent extraction behavior of the ionic liquid

Bridging phases at the morphotropic boundaries of lead oxide solid solutions

NARCIS (Netherlands)

Noheda, Beatriz; Cox, DE

2006-01-01

Ceramic solid solutions of PbZr1-xTixO3 (PZT) with compositions x similar or equal to 0.50 are well-known for their extraordinarily large piezoelectric responses. The latter are highly anisotropic, and it was recently shown that, for the rhombohedral compositions (x less than or similar to 0.5), the

Study of valence of cerium and praseodymium ions in Pr1-xCexO2 solid solutions

International Nuclear Information System (INIS)

Gartsman, K.G.; Kartenko, N.F.; Melekh, B.T.

1990-01-01

Effect of preparation conditions of Pr 1-x Ce x O 2 solid solutions on Ce and Pr ion valence within Pr 1-x Ce x O 2 system is studied. The data obtained enable to conclude that praseodymium may depending on annealing conditions change its state from Pr 3+ to Pr 4+ , while Ce 4+ is stable in Pr 1-x Ce x O 2 solid solutions

Solid solutions in the system Nd2(SeO4)3 - Sm2(SeO4)3 - H2O

International Nuclear Information System (INIS)

Serebrennikov, V.V.; Tsybukova, T.N.; Velikov, A.A.

1984-01-01

Using the method of isothermal solubility at 25 deg C the system Nd 2 (SeO 4 ) 3 -Sm 2 (SeO 4 ) 3 -H 2 O has been studied. Roentgenographic recording of solid ''residues'' is realized. For solid solutions energies of interchange and formation heats are calculated. Formation heats of solid solutions on the basis of samarium selenates are also found experimentally

Failure criterion effect on solid production prediction and selection of completion solution

Directory of Open Access Journals (Sweden)

Dariush Javani

2017-12-01

Full Text Available Production of fines together with reservoir fluid is called solid production. It varies from a few grams or less per ton of reservoir fluid posing only minor problems, to catastrophic amount possibly leading to erosion and complete filling of the borehole. This paper assesses solid production potential in a carbonate gas reservoir located in the south of Iran. Petrophysical logs obtained from the vertical well were employed to construct mechanical earth model. Then, two failure criteria, i.e. Mohr–Coulomb and Mogi–Coulomb, were used to investigate the potential of solid production of the well in the initial and depleted conditions of the reservoir. Using these two criteria, we estimated critical collapse pressure and compared them to the reservoir pressure. Solid production occurs if collapse pressure is greater than pore pressure. Results indicate that the two failure criteria show different estimations of solid production potential of the studied reservoir. Mohr–Coulomb failure criterion estimated solid production in both initial and depleted conditions, where Mogi–Coulomb criterion predicted no solid production in the initial condition of reservoir. Based on Mogi–Coulomb criterion, the well may not require completion solutions like perforated liner, until at least 60% of reservoir pressure was depleted which leads to decrease in operation cost and time.

Activity coefficients at infinite dilution of organic solutes in the ionic liquid trihexyl(tetradecyl)phosphonium tetrafluoroborate using gas-liquid chromatography at T = (313.15, 333.15, 353.15, and 373.15) K

International Nuclear Information System (INIS)

Tumba, Kaniki; Reddy, Prashant; Naidoo, Paramespri; Ramjugernath, Deresh

2011-01-01

Research highlights: → Activity coefficients at infinite dilution in the ionic liquid [3C 6 C 14 P][BF 4 ]. → Twenty-seven solutes investigated at T = (313.15, 333.15, 353.15, and 373.15) K. → [3C 6 C 14 P][BF 4 ] shows promise for the separation of aromatic and alcohol mixtures. - Abstract: Activity coefficients at infinite dilution have been measured by gas-liquid chromatography for 27 organic solutes (n-alkanes, 1-alkenes, 1-alkynes, cycloalkanes, aromatics, alcohols, and ketones) in the ionic liquid trihexyl(tetradecyl)phosphonium tetrafluoroborate [3C 6 C 14 P][BF 4 ]. The measurements were carried out at four different temperatures viz.T = (313.15, 333.15, 353.15, and 373.15) K. From the experimental data, partial molar excess enthalpy values at infinite dilution were calculated for the experimental temperature range. The selectivity values for the separation of n-hexane/benzene, cyclohexane/benzene, and methanol/benzene mixtures were determined from the experimental infinite dilution activity coefficient values. These values were compared to those available in the literature for other ionic liquids and commercial solvents, so as to assess the feasibility of employing [3C 6 C 14 P][BF 4 ] in solvent-enhanced industrial separations.

Thermochemical study of aqueous solutions of lithium diclofenac at 293.15-318.15 K

Science.gov (United States)

Manin, N. G.; Perlovich, G. L.; Fini, A.

2013-04-01

The enthalpies of solution and dilution of aqueous solutions of lithium diclofenac (LiDC) are measured in the concentration range of 0.002-0.047 m at 293.15, 298.15, 308.15, and 318.5 K using an isoperibolic calorimeter. The heat capacity of solid LiDC in the temperature range of 273.15-373.15 K is determined using a DSC 204 F1 Phoenix differential scanning calorimeter (NETZSCH, Germany). The virial coefficients of the enthalpy characteristics of a water-LiDC solution are derived in terms of the Pitzer model to calculate a wide range of thermodynamic properties of both the solution and its components. Changes in these characteristics as a function of concentration and temperature are discussed.

Hierarchical architectures of ZnS–In2S3 solid solution onto TiO2 nanofibers with high visible-light photocatalytic activity

International Nuclear Information System (INIS)

Liu, Chengbin; Meng, Deshui; Li, Yue; Wang, Longlu; Liu, Yutang; Luo, Shenglian

2015-01-01

Graphical abstract: A unique hierarchical architecture of ZnS–In 2 S 3 solid solution onto TiO 2 nanofibers was fabricated. The hierarchical heterostructures exhibit high visible light photocatalytic activity and outstanding recycling performance. - Highlights: • Novel hierarchical heterostructure of TiO 2 @ZnS–In 2 S 3 solid solution. • Efficient inhibition of ZnS–In 2 S 3 solid solution aggregation. • High visible light photocatalytic activity. • Highly stable recycling performance. - Abstract: A unique hierarchical architecture of ZnS–In 2 S 3 solid solution nanostructures onto TiO 2 nanofibers (TiO 2 @ZnS–In 2 S 3 ) has been successfully fabricated by simple hydrothermal method. The ZnS–In 2 S 3 solid solution nanostructures exhibit a diversity of morphologies: nanosheet, nanorod and nanoparticle. The porous TiO 2 nanofiber templates effectively inhibit the aggregation growth of ZnS–In 2 S 3 solid solution. The formation of ZnS–In 2 S 3 solid solution is proved by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) and the intimate contact between TiO 2 nanofibers and ZnS–In 2 S 3 solid solution favors fast transfer of photogenerated electrons. The trinary TiO 2 @ZnS–In 2 S 3 heterostructures exhibit high adsorption capacity and visible light photocatalytic activity for the degradation of rhodamine B dye (RhB), remarkably superior to pure TiO 2 nanofibers or binary structures (ZnS/TiO 2 nanofibers, In 2 S 3 /TiO 2 nanofibers and ZnS–In 2 S 3 solid solution). Under visible light irradiation the RhB photocatalytic degradation rate over TiO 2 @ZnS–In 2 S 3 heterostructures is about 16.7, 12.5, 6.3, 5.9, and 2.2 times that over pure TiO 2 nanofibers, ZnS nanoparticles, In 2 S 3 /TiO 2 nanofibers, ZnS/TiO 2 nanofibers, and ZnS-In 2 S 3 solid solution, respectively. Furthermore, the TiO 2 @ZnS–In 2 S 3 heterostructures show highly stable recycling performance

Picot-Benoit Effect in Polymer Solutions

Science.gov (United States)

Beaucage, Gregory; Sukumaran, Sathish; Ilavsky, Jan

2003-03-01

SAXS from polymers in solution is well described at intermediate (q = 0.01-0.1 Å-1) scattering vectors by scaling theory which predicts three regimes in concentration: dilute, semi-dilute and concentrated [1-3]. A persistent problem is the appearance of excess scattering at low-q, q molecular weight dependence for these fluctuations in the dilute and semi-dilute regimes. The later is unexpected since above c* scaling theory predicts no M dependencies due to screening [1-3]. The literature associates PB features with semi-dilute and concentrated solutions, yet we have observed excess scattering even in dilute solutions of polystyrene in cyclopentane. 1) de Gennes P-G, Scaling Concepts in Polymer Physics, 1979. 2) Strobl G, The Physics of Polymers, Berlin 1997. 3) Doi M, Introduction to Polymer Physics, Oxford 1997. 4) Benoit H, Picot C Pure Appl. Chem. 12 545 (1966). 5) Benoit H, Picot C Pure Appl. Chem. 12 1271 (1966). 6) Xie Y, et al. Physica A 232 94 (1996). 7) Korberstein JT, et al. Polymer 26 673 (1985). 8) Morfin I, et al. Macromolecules 32 7208 (1999). 9) Blanco CM, et al. Langmuir 16 8585 (2000).

First-principles investigations of solid solution strengthening in Al alloys

OpenAIRE

Ma, Duancheng

2012-01-01

Any material properties, in principle, can be reproduced or predicted by performing firstprinciples calculations. Nowadays, however, we are dealing with complex alloy compositions and processes. The complexities cannot be fully described by first-principles, because of the limited computational power. The primary objective of this study is to investigate an important engineering problem, solid solution strengthening, in a simplified manner. The simplified scheme should allow fast and reliable...

Analysis of the variation of the activity of a "9"9"mTc sample after dilution with saline solution

International Nuclear Information System (INIS)

Kuahara, L.T.; Correa, E.L.; Potiens, M.P.A.

2016-01-01

The activity meter is essential equipment in nuclear medicine services.To ensure its good operation and know the factors which may influence its readings is vital for the activity administered to the patient be correct. Many factors may influence the activity meter accuracy, such as the type of container, geometry, and radioactive material volume. The aim of this study was to analyze the measurements variations in 0.5 ml and 1.0 ml of "9"9"mTc pure and diluted in 2.5 ml of saline solution, in containers used in nuclear medicine. Variations of up to 4 % in measured values were found. (author)

Deep and shallow acceptor levels in solid solutions Pb0.98Sm0.02S

International Nuclear Information System (INIS)

Hasanov, H.A.; Rahimov, R.Sh.

2010-01-01

It is well known that the metal vacancies the energy levels of which take place between permitted energies of valency band, are the main acceptor centers in the led salts and solid solutions on their base. The aim of the given paper is founding of character of acceptor levels in single crystals Pb 0 .98Sm 0 .02S with low concentrations of charge carrier. The deep and shallow acceptor levels are found at investigation of Hall effect in Pb 0 .98Sm 0 .02S solid solution with character of low concentrations of charge carriers in crystals

Evaluation of disinfecting effect of 5% sodium hypochlorite solution diluted to 2:100 along with the use of disposable covers on HBV contaminated dental office surfaces and equipments

Directory of Open Access Journals (Sweden)

Arami S.

2008-04-01

Full Text Available Background and Aim: The efficiency of disinfecting materials and procedures in removal of contamination from dental surfaces and equipments is essential. In authors' previous study, daily use of 2:100 dilution of 5% sodium hypochlorite in water and disposable covers were recommended since HBV contamination was found on semi-critical parts of the operative dentistry department. The aim of this study was to evaluate the HBV contamination following application of the recommended procedures.Materials and Methods: The study was conducted in two parts. In the first cross-sectional part, samples were collected from 17 sites of dental surfaces. In the second interventional part samples were collected from 10 sites of 9 dental and 3 sites of 2 light cure units, before and after disinfection with 5% sodium hypochlorite solution diluted to 2:100. Sterile cotton swabs moistened with sterile BSAS (Bovine Serum Albumin in Sodium Chloride solution were used for sampling. Samples were tested by PCR technique in Pasteur Institute, Iran.Results: None of the samples collected in the first part of the study showed contamination. In the second part of the study, from 96 samples taken from various parts of dental and light cure units, before and after disinfection, there was only one HBV contaminated site before disinfection which showed no contamination after disinfection.Conclusion: Based on the results of this study, disinfecting procedure with 5% sodium hypochlorite solution diluted to 2:100 along with using disposable covers is effective in preventing HBV contamination.

Fluoride removal from diluted solutions by Donnan dialysis using full factorial design

Energy Technology Data Exchange (ETDEWEB)

Boubakri, Ali; Helali, Nawel; Tlili, Mohamed; Amor, Mohamed Ben [Center of Researches and Water Technologies, Soliman (Turkey)

2014-03-15

Excessive fluoride concentration in potable water can lead to fluorosis of teeth and bones. In the present study, Donnan dialysis (DD) is applied for the removal of fluoride ions from diluted sodium fluoride solutions. A four factor two level (2{sup 4}) full factorial design was used to investigate the influence of different physico-chemical parameters on fluoride removal efficiency (Y{sub F}) and fluoride flux (J{sub F}) through anion exchange membrane. The statistical design determines factors which have the important effects on Donnan dialysis performance and studies all interactions among the considered parameters. The four significant factors were initial fluoride concentration, feed flow rate, temperature and agitation speed. The experimental results and statistical analysis show that the temperature and agitation speed have positive effects on fluoride removal efficiency and the initial fluoride concentration has a negative effect. In the case of fluoride flux, feed flow rate and initial concentration are the main effect and all factors have a positive effect. The interaction between studied parameters was not negligible on two responses. A maximum fluoride removal of 75.52% was obtained under optimum conditions and the highest value of fluoride flux obtained was 2.4 mg/cm{sup 2}·h. Empirical regression models were also obtained and used to predict the flux and the fluoride removal profiles with satisfactory results.

The investigation of solid solutions thin interlayers in CdS/CdTe film heterosystems

International Nuclear Information System (INIS)

Khrypunov, G.; Boyko, B.; Chernykh, O.

1999-01-01

The photo-response spectral dependence of ITO/CdTe/Au/Cu and ITO/CdS/CdTe/Au/Cu film heterosystems were investigated. At illuminations ITO/CdS/CdTe/Au/Cu heterosystems on ITO side a photo-response maximum was observed for photon absorption with a wavelength of 0.87 μm that is stipulated by formation of CdS x Te 1-x solid solutions interlayer with band gap width less than in CdTe layer. By use optical measurement transmittance spectra was selected a spectral photosensitivity interval appropriate to the contribution of non-equilibrium charge carriers generated in solid solutions interlayer by photon absorption with energy less than CdTe film band gap

Fine interstitial clusters as recombinators in decomposing solid solutions under irradiation

International Nuclear Information System (INIS)

Trushin, Yu.V.

1991-01-01

Behaviour of interstitial clusters and their roll in processes of radiation swelling of metals are described. It is shown that occurrence of coherent advanced precipitations during decomposition of solid solutions under irradiation leads to matrix supersaturation over interstitial atoms. This enhances recombination of unlike defects due to vacancy precipitation on fine interstitial clusters. Evaluation of cluster sizes was conducted

Study of reaction sequences for formation of solid solution: 0,48 ...

African Journals Online (AJOL)

... of a low concentration of ions forming the perovskite structure PZT (Pb2+, Zr4+ et Ti4+) by other ions (Zn2+, Cr3+ et Sb+5 in our study) alters the reaction sequences training of the solid solution PZT and especially the formation of intermediate phase. Keywords: PZT / Calcination / TGA / DTA / RX / Piezoelectric Ceramics ...

Quinary wurtzite Zn-Ga-Ge-N-O solid solutions and their photocatalytic properties under visible light irradiation

Science.gov (United States)

Xie, Yinghao; Wu, Fangfang; Sun, Xiaoqin; Chen, Hongmei; Lv, Meilin; Ni, Shuang; Liu, Gang; Xu, Xiaoxiang

2016-01-01

Wurtzite solid solutions between GaN and ZnO highlight an intriguing paradigm for water splitting into hydrogen and oxygen using solar energy. However, large composition discrepancy often occurs inside the compound owing to the volatile nature of Zn, thereby prescribing rigorous terms on synthetic conditions. Here we demonstrate the merits of constituting quinary Zn-Ga-Ge-N-O solid solutions by introducing Ge into the wurtzite framework. The presence of Ge not only mitigates the vaporization of Zn but also strongly promotes particle crystallization. Synthetic details for these quinary compounds were systematically explored and their photocatalytic properties were thoroughly investigated. Proper starting molar ratios of Zn/Ga/Ge are of primary importance for single phase formation, high particle crystallinity and good photocatalytic performance. Efficient photocatalytic hydrogen and oxygen production from water were achieved for these quinary solid solutions which is strongly correlated with Ge content in the structure. Apparent quantum efficiency for optimized sample approaches 1.01% for hydrogen production and 1.14% for oxygen production. Theoretical calculation reveals the critical role of Zn for the band gap reduction in these solid solutions and their superior photocatalytic acitivity can be understood by the preservation of Zn in the structure as well as a good crystallinity after introducing Ge.

A decontamination system for chemical weapons agents using a liquid solution on a solid sorbent.

Science.gov (United States)

Waysbort, Daniel; McGarvey, David J; Creasy, William R; Morrissey, Kevin M; Hendrickson, David M; Durst, H Dupont

2009-01-30

A decontamination system for chemical warfare agents was developed and tested that combines a liquid decontamination reagent solution with solid sorbent particles. The components have fewer safety and environmental concerns than traditional chlorine bleach-based products or highly caustic solutions. The liquid solution, based on Decon Greentrade mark, has hydrogen peroxide and a carbonate buffer as active ingredients. The best solid sorbents were found to be a copolymer of ethylene glycol dimethacrylate and n-lauryl methacrylate (Polytrap 6603 Adsorber); or an allyl methacrylate cross-linked polymer (Poly-Pore E200 Adsorber). These solids are human and environmentally friendly and are commonly used in cosmetics. The decontaminant system was tested for reactivity with pinacolyl methylphosphonofluoridate (Soman, GD), bis(2-chloroethyl)sulfide (Mustard, HD), and S-(2-diisopropylaminoethyl) O-ethyl methylphosphonothioate (VX) by using NMR Spectroscopy. Molybdate ion (MoO(4)(-2)) was added to the decontaminant to catalyze the oxidation of HD. The molybdate ion provided a color change from pink to white when the oxidizing capacity of the system was exhausted. The decontaminant was effective for ratios of agent to decontaminant of up to 1:50 for VX (t(1/2) decontamination solution were measured to show that the sorbent decreased the vapor concentration of GD. The E200 sorbent had the additional advantage of absorbing aqueous decontamination solution without the addition of an organic co-solvent such as isopropanol, but the rate depended strongly on mixing for HD.

Activity coefficients at infinite dilution of organic solutes in diethylene glycol and triethylene glycol from gas–liquid chromatography

International Nuclear Information System (INIS)

Williams-Wynn, Mark D.; Letcher, Trevor M.; Naidoo, Paramespri; Ramjugernath, Deresh

2013-01-01

Highlights: • γ 13 ∞ values reported for 25 organic solutes in the solvents DEG and TEG. • Measurements undertaken using the glc technique at T = (333.2, 348.2, and 363.2) K. • Measurements at elevated temperature possible by pre-saturation of carrier gas. • Comparison of DEG and TEG performance with a number of solvents. -- Abstract: The infinite dilution activity coefficients for 25 hydrocarbon solutes in diethylene glycol (DEG) and triethylene glycol (TEG) were measured using the gas–liquid chromatography technique with pre-saturation of the carrier gas. The hydrocarbon solutes included n-alkanes, alk-1-enes, alk-1-ynes, cycloalkanes, alkylbenzenes and alkanols. At the temperatures at which measurements were conducted, the solvents were volatile, and pre-saturation was considered necessary. The measurements were made at T = (333.2, 348.2 and 363.2) K. Values of the selectivity and capacity relating to DEG and TEG, for two sets of mixtures, which are usually difficult to separate by distillation or solvent extraction, were calculated from the experimental results. The two sets of mixtures were: cyclohexane and benzene; and benzene and methanol. The results obtained in this work were then compared to values for other solvents, at similar temperatures, which were obtained or calculated from literature data

CSBB-ConeExclusion, adapting structure based solution virtual screening to libraries on solid support.

Science.gov (United States)

Shave, Steven; Auer, Manfred

2013-12-23

Combinatorial chemical libraries produced on solid support offer fast and cost-effective access to a large number of unique compounds. If such libraries are screened directly on-bead, the speed at which chemical space can be explored by chemists is much greater than that addressable using solution based synthesis and screening methods. Solution based screening has a large supporting body of software such as structure-based virtual screening tools which enable the prediction of protein-ligand complexes. Use of these techniques to predict the protein bound complexes of compounds synthesized on solid support neglects to take into account the conjugation site on the small molecule ligand. This may invalidate predicted binding modes, the linker may be clashing with protein atoms. We present CSBB-ConeExclusion, a methodology and computer program which provides a measure of the applicability of solution dockings to solid support. Output is given in the form of statistics for each docking pose, a unique 2D visualization method which can be used to determine applicability at a glance, and automatically generated PyMol scripts allowing visualization of protein atom incursion into a defined exclusion volume. CSBB-ConeExclusion is then exemplarically used to determine the optimum attachment point for a purine library targeting cyclin-dependent kinase 2 CDK2.

The solidification behavior of dilute aluminium-scandium alloys

International Nuclear Information System (INIS)

Norman, A.F.; Prangnell, P.B.; McEwen, R.S.

1998-01-01

The solidification behavior of dilute Sc containing Al alloys has been investigated. In binary Al-Sc alloys, Sc additions greater than the eutectic composition (0.55 wt%) were found to produce a remarkable refinement in the grain size of aluminum castings, of two orders of magnitude, due to the formation of the primary Al 3 Sc intermetallic phase during solidification. The refinement in grain size only occurred in hypereutectic compositions and was shown to be far greater than can be achieved by conventional Al grain refiners. Grain refinement by the addition of Sc is accompanied by a change in growth morphology from dendritic, in the large unrefined grains, to fine spherical grains with a divorced eutectic appearing on the grain boundaries in the refined castings. Similar levels of refinement were observed in Al-Sc-Zr and Al-Cu-Sc alloys. In the latter, a change in the segregation behavior of Cu was observed, from a strongly interdendritic segregation pattern to a more homogeneous distribution. The supersaturated Al-Sc solid solution can decompose via a discontinuous precipitation reaction to form coherent rod-like precipitates of the L1 2 Al 3 Sc phase

Influence of lanthanium atoms on the physico-chemical properties of GeS0,5Se0,5 solid solutions

International Nuclear Information System (INIS)

Murguzov, M.I.; Alakbarov, A.S.; Bayramov, R.B.

2010-01-01

By the methods of physical-chemical analysis (DTA, X-ray, MSA, as well as measurement of microhardness and density determination) the influence of La on the physico-chemical properties of solid solutions (GeS 0 ,5Se 0 ,5) 1 -x(La) x was studied and its microdiagram was plotted. At room temperature the GeS 0 ,5Se 0 ,5 based solid solid solution extent to 4 at. percent La. The dependence of lanthane microhardness was studied

Dynamic nuclear polarization methods in solids and solutions to explore membrane proteins and membrane systems.

Science.gov (United States)

Cheng, Chi-Yuan; Han, Songi

2013-01-01

Membrane proteins regulate vital cellular processes, including signaling, ion transport, and vesicular trafficking. Obtaining experimental access to their structures, conformational fluctuations, orientations, locations, and hydration in membrane environments, as well as the lipid membrane properties, is critical to understanding their functions. Dynamic nuclear polarization (DNP) of frozen solids can dramatically boost the sensitivity of current solid-state nuclear magnetic resonance tools to enhance access to membrane protein structures in native membrane environments. Overhauser DNP in the solution state can map out the local and site-specific hydration dynamics landscape of membrane proteins and lipid membranes, critically complementing the structural and dynamics information obtained by electron paramagnetic resonance spectroscopy. Here, we provide an overview of how DNP methods in solids and solutions can significantly increase our understanding of membrane protein structures, dynamics, functions, and hydration in complex biological membrane environments.

The molecular properties of biochar carbon released in dilute acidic solution and its effects on maize seed germination.

Science.gov (United States)

Sun, Jingling; Drosos, Marios; Mazzei, Pierluigi; Savy, Davide; Todisco, Daniele; Vinci, Giovanni; Pan, Genxing; Piccolo, Alessandro

2017-01-15

It is not yet clear whether the carbon released from biochar in the soil solution stimulates biological activities. Soluble fractions (AQU) from wheat and maize biochars, whose molecular content was thoroughly characterized by FTIR, 13 C and 1 H NMR, and high-resolution ESI-IT-TOF-MS, were separated in dilute acidic solution to simulate soil rhizospheric conditions and their effects evaluated on maize seeds germination activity. Elongation of maize-seeds coleoptile was significantly promoted by maize biochar AQU, whereas it was inhibited by wheat biochar AQU. Both AQU fractions contained relatively small heterocyclic nitrogen compounds, whose structures were accounted by their spectroscopic properties. Point-of-Zero-Charge (PZC) values and van Krevelen plots of identified masses of soluble components suggested that the dissolved carbon from maize biochar behaved as humic-like supramolecular material capable to adhere to seedlings and deliver bioactive molecules. These findings contribute to understand the biostimulation potential of biochars from crop biomasses when applied in agricultural production. Copyright © 2016 Elsevier B.V. All rights reserved.

Optical and Piezoelectric Study of KNN Solid Solutions Co-Doped with La-Mn and Eu-Fe

Directory of Open Access Journals (Sweden)

Jesús-Alejandro Peña-Jiménez

2016-09-01

Full Text Available The solid-state method was used to synthesize single phase potassium-sodium niobate (KNN co-doped with the La3+–Mn4+ and Eu3+–Fe3+ ion pairs. Structural determination of all studied solid solutions was accomplished by XRD and Rietveld refinement method. Electron paramagnetic resonance (EPR studies were performed to determine the oxidation state of paramagnetic centers. Optical spectroscopy measurements, excitation, emission and decay lifetime were carried out for each solid solution. The present study reveals that doping KNN with La3+–Mn4+ and Eu3+–Fe3+ at concentrations of 0.5 mol % and 1 mol %, respectively, improves the ferroelectric and piezoelectric behavior and induce the generation of optical properties in the material for potential applications.

Preparation, structural, dielectric and magnetic properties of LaFeO3–PbTiO3 solid solutions

International Nuclear Information System (INIS)

Ivanov, S.A.; Tellgren, R.; Porcher, F.; Ericsson, T.; Mosunov, A.; Beran, P.; Korchagina, S.K.; Kumar, P. Anil; Mathieu, R.; Nordblad, P.

2012-01-01

Highlights: ► Solid-solutions of (1−x)LaFeO 3 –(x)PbTiO 3 were synthesized by solid-state reaction. ► XRPD and NPD evidence orthorhombic (x 0.8) crystal structures. ► LaFeO 3 -rich compositions order antiferromagnetically (x 3 -rich compositions exhibit ferroelectric order (x larger than 0.8). ► Magnetic and dielectric (relaxor) ordering coexist near room-temperature around x = 0.4. -- Abstract: Solid solutions of (1−x)LaFeO 3 –(x)PbTiO 3 (0 3+ cations in the B-site with propagation vector k = (0,0,0). Based on the obtained experimental data, a combined structural and magnetic phase diagram has been constructed. The factors governing the structural, dielectric and magnetic properties of (1−x)LaFeO 3 –(x)PbTiO 3 solid solutions are discussed, as well as their possible multiferroicity.

Determination of activity coefficients at infinite dilution of water and organic solutes (polar and non-polar) in the Ammoeng 100 ionic liquid at T = (308.15, 313.5, 323.15, and 333.15) K

International Nuclear Information System (INIS)

Reddy, Prashant; Chiyen, Kaleng J.; Deenadayalu, Nirmala; Ramjugernath, Deresh

2011-01-01

Highlights: → Activity coefficients at infinite dilution in the ionic liquid Ammoeng 100. → Twenty-seven solutes investigated at T = (308.15, 313.15, 323.15, and 333.15) K. → Ammoeng 100 not suited to aromatic/aliphatic and alkane/alcohol separations. - Abstract: Activity coefficients at infinite dilution (γ 13 ∞ ) have been determined for 27 solutes, viz. water and organic compounds (n-alkanes, cycloalkanes, 1-alkenes, 1-alkynes, aromatics, alcohols, and ketones) in the ionic liquid Ammoeng 100, by gas-liquid chromatography at four different temperatures, T = (308.15, 313.15, 323.15, and 333.15) K. Columns with different phase loadings (20 to 24)% of the ionic liquid in the stationary phase were employed to obtain γ 13 ∞ values at each temperature investigated. Partial molar excess enthalpies at infinite dilution (ΔH 1 E,∞ ) were calculated for the solutes from the temperature dependency relationship of the ln(γ 13 ∞ ) values for the temperature range in this study. The uncertainties in the determinations of the γ 13 ∞ and ΔH 1 E,∞ values are 6% and 10%, respectively. Selectivity values at infinite dilution (S ij ∞ ), have been computed from the γ 13 ∞ values to assess the potential candidacy of the Ammoeng 100 ionic liquid for the separation of alkane/alcohol mixtures. The results from this study have been compared to those available for several ionic liquids from previous investigations.

Process for final storage of high level radioactive fission product solution

International Nuclear Information System (INIS)

Ellis, J.R.B.; Fries, B.A.

1984-01-01

In this process for the storage of an aqueous solution of radioactive nuclides, the solution is diluted with system water, which is obtained from a reservoir below the bottom of the sea in a porous geological stratum. After dilution, the diluted solution is injected into the same geological stratum under the bottom of the sea. (orig.) [de

Fabrication of nanocrystalline alloys Cu–Cr–Mo super satured solid solution by mechanical alloying

Energy Technology Data Exchange (ETDEWEB)

Aguilar, C., E-mail: claudio.aguilar@usm.cl [Departamento de Ingeniería Metalúrgica y Materiales, Universidad Técnica Federico Santa María, Av. España 1680, Valparaíso (Chile); Guzmán, D. [Departamento de Ingeniería en Metalurgia, Facultad de Ingeniería, Universidad de Atacama y Centro Regional de Investigación y Desarrollo Sustentable de Atacama (CRIDESAT), Av. Copayapu 485, Copiapó (Chile); Castro, F.; Martínez, V.; Cuevas, F. de las [Centro de Estudios e Investigaciones Técnicas de Gipuzkoa, Paseo de Manuel Lardizábal, N° 15, 20018 San Sebastián (Spain); Lascano, S. [Departamento de Ingeniería Mecánica, Universidad Técnica Federico Santa María, Av. España 1680, Valparaíso (Chile); Muthiah, T. [Departamento de Ingeniería Metalúrgica y Materiales, Universidad Técnica Federico Santa María, Av. España 1680, Valparaíso (Chile)

2014-08-01

This work discusses the extension of solid solubility of Cr and Mo in Cu processed by mechanical alloying. Three alloys processed, Cu–5Cr–5Mo, Cu–10Cr–10Mo and Cu–15Cr–15Mo (weight%) using a SPEX mill. Gibbs free energy of mixing values 10, 15 and 20 kJ mol{sup −1} were calculated for these three alloys respectively by using the Miedema's model. The crystallite size decreases and dislocation density increases when the milling time increases, so Gibbs free energy storage in powders increases by the presence of crystalline defects. The energy produced by crystallite boundaries and strain dislocations were estimated and compared with Gibbs free energy of mixing values. The energy storage values by the presence of crystalline defects were higher than Gibbs free energy of mixing at 120 h for Cu–5Cr–5Mo, 130 h for Cu–10Cr–10Mo and 150 h for Cu–15Cr–15Mo. During milling, crystalline defects are produced that increases the Gibbs free energy storage and thus the Gibbs free energy curves are moved upwards and hence the solubility limit changes. Therefore, the three alloys form solid solutions after these milling time, which are supported with the XRD results. - Highlights: • Extension of solid solution Cr and Mo in Cu achieved by mechanical alloying. • X-ray characterization of Cu–Cr–Mo system processed by mechanical alloying. • Thermodynamics analysis of formation of solid solution of the Cu–Cr–Mo system.

Phase relations and Gibbs energies of spinel phases and solid solutions in the system Mg-Rh-O

Energy Technology Data Exchange (ETDEWEB)

Jacob, K.T., E-mail: katob@materials.iisc.ernet.in [Department of Materials Engineering, Indian Institute of Science, Bangalore 560 012 (India); Prusty, Debadutta [Department of Materials Engineering, Indian Institute of Science, Bangalore 560 012 (India); Kale, G.M. [Institute for Materials Research, University of Leeds, Leeds, LS2 9JT (United Kingdom)

2012-02-05

Highlights: Black-Right-Pointing-Pointer Refinement of phase diagram for the system Mg-Rh-O and thermodynamic data for spinel compounds MgRh{sub 2}O{sub 4} and Mg{sub 2}RhO{sub 4} is presented. Black-Right-Pointing-Pointer A solid-state electrochemical cell is used for thermodynamic measurement. Black-Right-Pointing-Pointer An advanced design of the solid-state electrochemical cell incorporating buffer electrodes is deployed to minimize polarization of working electrode. Black-Right-Pointing-Pointer Regular solution model for the spinel solid solution MgRh{sub 2}O{sub 4} - Mg{sub 2}RhO{sub 4} based on ideal mixing of cations on the octahedral site is proposed. Black-Right-Pointing-Pointer Factors responsible for stabilization of tetravalent rhodium in spinel compounds are identified. - Abstract: Pure stoichiometric MgRh{sub 2}O{sub 4} could not be prepared by solid state reaction from an equimolar mixture of MgO and Rh{sub 2}O{sub 3} in air. The spinel phase formed always contained excess of Mg and traces of Rh or Rh{sub 2}O{sub 3}. The spinel phase can be considered as a solid solution of Mg{sub 2}RhO{sub 4} in MgRh{sub 2}O{sub 4}. The compositions of the spinel solid solution in equilibrium with different phases in the ternary system Mg-Rh-O were determined by electron probe microanalysis. The oxygen potential established by the equilibrium between Rh + MgO + Mg{sub 1+x}Rh{sub 2-x}O{sub 4} was measured as a function of temperature using a solid-state cell incorporating yttria-stabilized zirconia as an electrolyte and pure oxygen at 0.1 MPa as the reference electrode. To avoid polarization of the working electrode during the measurements, an improved design of the cell with a buffer electrode was used. The standard Gibbs energies of formation of MgRh{sub 2}O{sub 4} and Mg{sub 2}RhO{sub 4} were deduced from the measured electromotive force (e.m.f.) by invoking a model for the spinel solid solution. The parameters of the model were optimized using the measured

Solubility behaviour of antimony(III) and antimony(V) solids in basic aqueous solutions at 300{sup o}C

Energy Technology Data Exchange (ETDEWEB)

Lemire, R.J.; Tosello, N.B.; Halliday, J.D

1999-12-01

The major contributions of the isotopes {sup 122}Sb and {sup 124}Sb to activity transport in a CANDU reactor primary heat transport system (HTS), have been associated with oxygen ingress during reactor shutdown. As part of a program to minimize the release and redeposition of these isotopes, the solubilities of antimony(III) and (V) oxides and salts have been measured in basic solutions at temperatures from 25 to 300{sup o}C. The results provide information on the charge and the stability as a function of temperature of antimony solution species and, hence, a guide to the trends in the temperature dependence of the solubilities of antimony solids. In solutions in which oxidation of antimony(III) to antimony(V) is minimized, the solubility of Sb{sub 2}O{sub 3} increases by about two orders of magnitude between 25 and 200{sup o}C, and then levels out or decreases slightly. At 250{sup o}C, in oxidizing solutions, Sb{sub 2}O{sub 5}{center_dot}xH{sub 2}O and simple sodium antimonate(V) were found to be unstable in sodium hydroxide solutions with respect to the solid, Na{sub 2{alpha}}[H(H{sub 2}O)]{sub 2-2{alpha}}Sb{sub 2}O{sub 6}, which has a pyrochlore structure. The solubility of this partially protonated sodium antimonate increases from 25 to 200{sup o}C and decreases at temperatures above 250{sup o}C. These solubility changes for the antimony (V) solids reflect changes in the stability of the anionic antimony solution species (SbO{sub 3}{sup -} or Sb(OH){sub 6}{sup -}), even though the compositions of antimony-containing solids in basic oxidizing solutions are strongly dependent on the cations and their aqueous phase concentrations. All solids used in the present experiments would be expected to generate total solution antimony concentrations {>=} 0.00005 mol{center_dot}dm{sup -3} in any neutral or basic aqueous solutions (assuming no added sodium salts). Therefore, under HTS conditions, precipitation of any antimony oxides or mixed oxides is unlikely. It cannot be

Geological constraints on the thermodynamic properties of the stilbite - stellerite solid solution in low-grade metabasalts

Science.gov (United States)

Fridriksson, Thráinn; Neuhoff, Philip S.; Arnórsson, Stefán; Bird, Dennis K.

2001-11-01

Standard state thermodynamic data for stilbite (Ca2NaAl5Si13O36∗16H2O) and stellerite (Ca2Al4Si14O36∗14H2O), together with mixing properties of the stilbite -stellerite solid solution (stilbite SS) are derived through assessment of geological observations of stilbite SS compositions in metabasalts, experimental phase equilibria, and calorimetric observations. Measured compositions of stilbite SS in Tertiary metabasalts in Iceland and Icelandic geothermal systems change systematically towards the stellerite endmember with increasing stratigraphic depth and temperature. Standard molal volumes, heat capacities, and entropies for the endmembers of the solid solution are derived through critical review of published crystallographic and calorimetric data for natural stilbite SS. Standard molal Gibbs energies of formation at 298.15 K and 1 bar for stilbite (-4,946,475cal mol-1) and stellerite (-4,762,036 cal mol-1) and the mixing properties of the solid solution are retrieved from observed phase- and compositional-relations in metabasalts at Berufjördur, Iceland, measured temperatures of zeolite mineral distribution in active geothermal systems, and published observations of reversed phase equilibria. Mixing in stilbite SS can be described with an athermal solid solution model. Thermodynamic data resulting from our analysis provide close correlation between compositions of stilbite SS in Icelandic geothermal systems predicted from compositions of geothermal solutions and observed compositions of these minerals in low-grade metabasalts of Iceland, as well as the observed temperature of the stilbite SS to laumontite (leonhardite) transition in Icelandic geothermal systems. Stilbite SS composition in metabasalts is a sensitive function of temperature, fluid composition, coexisting minerals (especially silica polymorphs) and geothermal gradient.

Hydrogen storage in TiCr1.2(FeV)x BCC solid solutions

International Nuclear Information System (INIS)

Santos, Sydney F.; Huot, Jacques

2009-01-01

The Ti-V-based BCC solid solutions have been considered attractive candidates for hydrogen storage due to their relatively large hydrogen absorbing capacities near room temperature. In spite of this, improvements of some issues should be achieved to allow the technological applications of these alloys. Higher reversible hydrogen storage capacity, decreasing the hysteresis of PCI curves, and decrease in the cost of the raw materials are needed. In the case of vanadium-rich BCC solid solutions, which usually have large hydrogen storage capacities, the search for raw materials with lower cost is mandatory since pure vanadium is quite expensive. Recently, the substitutions of vanadium in these alloys have been tried and some interesting results were achieved by replacing vanadium by commercial ferrovanadium (FeV) alloy. In the present work, this approach was also adopted and TiCr 1.2 (FeV) x alloy series was investigated. The XRD patterns showed the co-existence of a BCC solid solution and a C14 Laves phase in these alloys. SEM analysis showed the alloys consisted of dendritic microstructure and C14 colonies. The amount of C14 phase increases when the amount of (FeV) decreases in these alloys. Concerning the hydrogen storage, the best results were obtained for the TiCr 1.2 (FeV) 0.4 alloy, which achieved 2.79 mass% of hydrogen storage capacity and 1.36 mass% of reversible hydrogen storage capacity

Investigation of Possible Maillard Reaction Between Acyclovir and Dextrose upon Dilution Prior to Parenteral Administration.

Science.gov (United States)

Siahi Shadbad, Mohammad Reza; Ghaderi, Faranak; Hatami, Leila; Monajjemzadeh, Farnaz

2016-12-01

In this study the stability of parenteral acyclovir (ACV) when diluted in dextrose (DEX) as large volume intravenous fluid preparation (LVIF) was evaluated and the possible Maillard reaction adducts were monitored in the recommended infusion time. Different physicochemical methods were used to evaluate the Maillard reaction of dextrose with ACV to track the reaction in real infusion condition. Other large volume intravenous fluids were checked regarding the diluted drug stability profile. Differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and mass data proved the reaction of glucose with dextrose. A Maillard-specific high performance liquid chromatography (HPLC) method was used to track the reaction in real infusion condition in vitro. The nucleophilic reaction occurred in diluted parenteral preparations of acyclovir in 5% dextrose solutions. The best diluent solution was also selected as sodium chloride and introduced based on drug stability and also its adsorption onto different infusion sets (PVC or non PVC) to provide an acceptable administration protocol in clinical practices. Although, the Maillard reaction was proved and successfully tracked in diluted solutions, and the level of drug loss when diluted in dextrose was reported to be between 0.27 up to 1.03% of the initial content. There was no drug adsorption to common infusion sets. The best diluent for parenteral acyclovir is sodium chloride large volume intravenous fluid.

Four Thermochromic o-Hydroxy Schiff Bases of α-Aminodiphenylmethane: Solution and Solid State Study

Directory of Open Access Journals (Sweden)

Marija Zbačnik

2017-01-01

Full Text Available More than a hundred years after the first studies of the photo- and thermochromism of o-hydroxy Schiff bases (imines, it is still an intriguing topic that fascinates several research groups around the world. The reasons for such behavior are still under investigation, and this work is a part of it. We report the solution-based and mechanochemical synthesis of four o-hydroxy imines derived from α-aminodiphenylmethane. The thermochromic properties were studied for the single crystal and polycrystalline samples of the imines. The supramolecular impact on the keto-enol tautomerism in the solid state was studied using SCXRD and NMR, while NMR spectroscopy was used for the solution state. All four imines are thermochromic, although the color changes of the single crystals are not as strong as of the polycrystalline samples. One of the imines shows negative thermochromism, and that one is in keto-amine tautomeric form, both in the solid state as in solution.

Degradation of chitosan hydrogel dispersed in dilute carboxylic acids by solution plasma and evaluation of anticancer activity of degraded products

Science.gov (United States)

Chokradjaroen, Chayanaphat; Rujiravanit, Ratana; Theeramunkong, Sewan; Saito, Nagahiro

2018-01-01

Chitosan is a polysaccharide that has been extensively studied in the field of biomedicine, especially its water-soluble degraded products called chitooligosaccharides (COS). In this study, COS were produced by the degradation of chitosan hydrogel dispersed in a dilute solution (i.e., 1.55 mM) of various kinds of carboxylic acids using a non-thermal plasma technology called solution plasma (SP). The degradation rates of chitosan were influenced by the type of carboxylic acids, depending on the interaction between chitosan and each carboxylic acid. After SP treatment, the water-soluble degraded products containing COS could be easily separated from the water-insoluble residue of chitosan hydrogel by centrifugation. The production yields of the COS were mostly higher than 55%. Furthermore, the obtained COS products were evaluated for their inhibitory effect as well as their selectivity against human lung cancer cells (H460) and human lung normal cells (MRC-5).

Kinetics and thermodynamics of the dissolution of Th1-xMxO2 solid solutions (M = U, Pu)

International Nuclear Information System (INIS)

Hubert, S.; Heisbourg, G.; Dacheux, N.; Moisy, Ph.; Purans, J.

2004-01-01

Kinetics of the dissolution of Th 1-x M x O 2 (M = U, Pu) solid solutions was investigated as a function of several chemical parameters such as pH, substitution ratio, temperature, ionic strength, and electrolyte. Several compositions of Th 1-x U x O 2 and Th 1-x Pu x O 2 were synthesized and characterized before and after leaching by using several methods such as XRD, EXAFS, BET, PIXE, SEM, and XPS. Leaching tests were performed in nitric, hydrochloric or sulfuric media and groundwater. The normalized dissolution rates were evaluated for Th 1-x U x O 2 , and Th 0.88 Pu 0.12 O 2 leading to the determination of the partial order related to the proton concentration, n, and to the corresponding normalized dissolution rate constant at pH = 0, k'T. While for Th enriched solids, the solid solutions Th 1-x U x O 2 have the same dissolution behaviour than ThO 2 with a partial order n ∼ 0.3, in the case of uranium enriched solids, Th 1-x U x O 2 has the same dissolution behaviour than UO 2 with a partial order of n = 1, indicating that uranium oxidation rate becomes the limiting step of the dissolution process. The stoichiometry of the release of both actinides (U or Pu, Th) was verified until the precipitation of thorium occurred in the leachate for pH > 2, while uranium was released in the solution as an uranyl form. For uranium enriched solid solutions, thermodynamic equilibrium was reached after 100 days, and solubility constant of secondary phase was determined. In the case of Th 1-x Pu x O 2 , the dissolution behaviour is similar to that of ThO 2 , but only kinetic aspect of the dissolution can be studied. From the analysis of XPS and EXAFS data on leached and un-leached Th 1-x U x O 2 samples, the dissolution mechanism of solid solutions was explained and will be discussed. The role of the electrolytes on the dissolution of the solid solutions is discussed. Kinetics parameters of dissolution are also given in groundwater and in neutral media

Solid-solution-like ZnO/C composites as excellent anode materials for lithium ion batteries

International Nuclear Information System (INIS)

Zhang, Guanhua; Zhang, Hang; Zhang, Xiang; Zeng, Wei; Su, Qingmei; Du, Gaohui; Duan, Huigao

2015-01-01

Exploring advanced anode materials to maximize the capacity of lithium ion batteries has been an active research area for decades. Constructing composites materials has been proved to be one of the most effective methods to achieve higher capacity due to the synergistic effect. In this work, we proposed and demonstrated a concept of solid-solution-like ZnO/C composites to approach the largest possible synergistic effect by introducing the most interfaces and minimizing the pulverization. The solid-solution-like ZnO/C electrode could achieve a high reversible capacity of 813.3 mAh g −1 at a current density of 100 mA g −1 after 100 cycles with a decrease rate of only 0.4% per cycle. Moreover, the discharge capacity still maintained 53.5% of the original value even when the current density increased to 40 times as much as the original, showing a distinguished rate performance. In addition, such solid-solution-like nanofibers can be easily prepared because of their compatibility with the existing industrial PAN-based spinning process. This may pave the way to mass produce lithium ion batteries with significantly enhanced performance using existing low-cost commercial facilities and recipes.

A Review of Solid-Solution Models of High-Entropy Alloys Based on Ab Initio Calculations

Directory of Open Access Journals (Sweden)

Fuyang Tian

2017-11-01

Full Text Available Similar to the importance of XRD in experiments, ab initio calculations, as a powerful tool, have been applied to predict the new potential materials and investigate the intrinsic properties of materials in theory. As a typical solid-solution material, the large degree of uncertainty of high-entropy alloys (HEAs results in the difficulty of ab initio calculations application to HEAs. The present review focuses on the available ab initio based solid-solution models (virtual lattice approximation, coherent potential approximation, special quasirandom structure, similar local atomic environment, maximum-entropy method, and hybrid Monte Carlo/molecular dynamics and their applications and limits in single phase HEAs.

STAR POLYMERS IN GOOD SOLVENTS FROM DILUTE TO CONCENTRATED REGIMES: CROSSOVER APPROACH

Directory of Open Access Journals (Sweden)

S.B.Kiselev

2002-01-01

Full Text Available An introduction is given to the crossover theory of the conformational and thermodynamic properties of star polymers in good solvents. The crossover theory is tested against Monte Carlo simulation data for the structure and thermodynamics of model star polymers. In good solvent conditions, star polymers approach a "universal" limit as N → ∞, however, there are two types of approach towards this limit. In the dilute regime, a critical degree of polymerization N* is found to play a similar role as the Ginzburg number in the crossover theory for critical phenomena in simple fluids. A rescaled penetration function is found to control the free energy of star polymer solutions in the dilute and semidilute regions. This equation of state captures the scaling behaviour of polymer solutions in the dilute/semidilute regimes and also performs well in the concentrated regimes, where the details of the monomer-monomer interactions become important.

CONDENSED MATTER: STRUCTURE, MECHANICAL AND THERMAL PROPERTIES: Molecular Dynamics Study of Stability of Solid Solutions and Amorphous Phase in the Cu-Al System

Science.gov (United States)

Yang, Bin; Lai, Wen-Sheng

2009-06-01

The relative stability of fcc and bcc solid solutions and amorphous phase with different compositions in the Cu-Al system is studied by molecular dynamics simulations with n-body potentials. For Cu1-xAlx alloys, the calculations show that the fcc solid solution has the lowest energies in the composition region with x 0.72, while the bee solid solution has the lowest energies in the central composition range, in agreement with the ball-milling experiments that a single bcc solid solution with 0.30 < x < 0.70 is obtained. The evolution of structures in solid solutions and amorphous phase is studied by the coordination number (CN) and bond-length analysis so as to unveil the underlying physics. It is found that the energy sequence among three phases is determined by the competition in energy change originating from the bond length and CNs (or the number of bonds).

Rheology of dilute acid hydrolyzed corn stover at high solids concentration.

Science.gov (United States)

Ehrhardt, M R; Monz, T O; Root, T W; Connelly, R K; Scott, C T; Klingenberg, D J

2010-02-01

The rheological properties of acid hydrolyzed corn stover at high solids concentration (20-35 wt.%) were investigated using torque rheometry. These materials are yield stress fluids whose rheological properties can be well represented by the Bingham model. Yield stresses increase with increasing solids concentration and decrease with increasing hydrolysis reaction temperature, acid concentration, and rheometer temperature. Plastic viscosities increase with increasing solids concentration and tend to decrease with increasing reaction temperature and acid concentration. The solids concentration dependence of the yield stress is consistent with that reported for other fibrous systems. The changes in yield stress with reaction conditions are consistent with observed changes in particle size. This study illustrates that torque rheometry can be used effectively to measure rheological properties of concentrated biomass.

Np(V) carbonates in solid state and aqueous solution

International Nuclear Information System (INIS)

Meinrath, G.

1994-01-01

The solubility of NaNpO 2 CO 3 (s) in 0.1M perchlorate solution at 25 deg C in equilibrium with 1.0% CO 2 /N 2 atmosphere has been investigated as a function of pH/lg [CO 3 2- ]. The solid phase was found hexagonal with a=1008.1±0.3 pm and c=991.1±0.2 pm. A solubility product of lg Ksp(NaNpO 2 CO 3 ) = -10.22±0.02 and a formation constant of the first Np(V) carbonato species of lg β 01 = 4.52±0.02 was evaluated. For the dicarbonato species an upper limit of lg lg β 02 2 partial pressure gave evidence that carbonato species are prevailing in solutions at both 1% and 0.03% CO 2 partial pressures. (author) 26 refs.; 4 figs.; 3 tabs

Approaches of aroma extraction dilution analysis (AEDA) for headspace solid phase microextraction and gas chromatography-olfactometry (HS-SPME-GC-O): Altering sample amount, diluting the sample or adjusting split ratio?

Science.gov (United States)

Feng, Yunzi; Cai, Yu; Sun-Waterhouse, Dongxiao; Cui, Chun; Su, Guowan; Lin, Lianzhu; Zhao, Mouming

2015-11-15

Aroma extract dilution analysis (AEDA) is widely used for the screening of aroma-active compounds in gas chromatography-olfactometry (GC-O). In this study, three aroma dilution methods, (I) using different test sample volumes, (II) diluting samples, and (III) adjusting the GC injector split ratio, were compared for the analysis of volatiles by using HS-SPME-AEDA. Results showed that adjusting the GC injector split ratio (III) was the most desirable approach, based on the linearity relationships between Ln (normalised peak area) and Ln (normalised flavour dilution factors). Thereafter this dilution method was applied in the analysis of aroma-active compounds in Japanese soy sauce and 36 key odorants were found in this study. The most intense aroma-active components in Japanese soy sauce were: ethyl 2-methylpropanoate, ethyl 2-methylbutanoate, ethyl 3-methylbutanoate, ethyl 4-methylpentanoate, 3-(methylthio)propanal, 1-octen-3-ol, 2-methoxyphenol, 4-ethyl-2-methoxyphenol, 2-methoxy-4-vinylphenol, 2-phenylethanol, and 4-hydroxy-5-ethyl-2-methyl-3(2H)-furanone. Copyright © 2015. Published by Elsevier Ltd.

Activity coefficients at infinite dilution for solutes in the trioctylmethylammonium bis(trifluoromethylsulfonyl)imide ionic liquid using gas-liquid chromatography

International Nuclear Information System (INIS)

Gwala, Nobuhle V.; Deenadayalu, Nirmala; Tumba, Kaniki; Ramjugernath, Deresh

2010-01-01

The activity coefficient at infinite dilution (γ 13 ∞ ) for 30 solutes: alkanes, alkenes, cycloalkanes, alkynes, ketones, alcohols, and aromatic compounds was determined from gas-liquid chromatography (glc) measurements at three temperatures (303.15, 313.15, and 323.15) K. The ionic liquid: trioctylmethylammonium bis(trifluoromethylsulfonyl)imide, was used as the stationary phase. For each temperature, γ 13 ∞ values were determined using two columns with different mass percent packing of the ionic liquid. The selectivity (S 12 ∞ ) value was calculated from the γ 13 ∞ to determine the suitability of the solvent as a potential entrainer for extractive distillation in the separation of an hexane/benzene mixture, indicative of a typical industrial separation problem for benchmarking purposes.

States of atoms and interatomic interactions in complex perovskite-like oxides. Communication XXIII. Magnetic dilution in the La(Sr)NiO3-LaGaO3

International Nuclear Information System (INIS)

Chezhina, N.V.; Bodritskaya, Eh.V.; Zhuk, N.A.

2008-01-01

Magnetic susceptibility of dilute solid solutions of lanthanum gallates doped with nickel and also with nickel and strontium was studied. Calculations showed that the main contribution into the exchange interactions in gallates doped with nickel is made by dimers formed by low-spin nickel(III) (J -20 cm -1 ), and in gallates doped with strontium and nickel the main contribution is due to dimers formed by high-and low-spin nickel (J 10 cm -1 ). Electrical conductivity measurements showed that the samples under study are electron and ion conductors [ru

Physical metallurgy

International Nuclear Information System (INIS)

Adda, Y.; Dupouy, J.M.; Philibert, J.; Quere, Y.

1976-01-01

In this manual, the following topics are discussed: thermodynamics of solid solutions, phase diagrams, properties of dilute solid solutions, structure of solid solutions, thermodynamics of surfaces, perfect dislocations, partial dislocations and stacking faults, interfaces, point defects

Solution and solid-phase halogen and C-H hydrogen bonding to perrhenate.

Science.gov (United States)

Massena, Casey J; Riel, Asia Marie S; Neuhaus, George F; Decato, Daniel A; Berryman, Orion B

2015-01-28

(1)H NMR spectroscopic and X-ray crystallographic investigations of a 1,3-bis(4-ethynyl-3-iodopyridinium)benzene scaffold with perrhenate reveal strong halogen bonding in solution, and bidentate association in the solid state. A nearly isostructural host molecule demonstrates significant C-H hydrogen bonding to perrhenate in the same phases.

Ca{sub 2−x}Li{sub 2x}GeO{sub 4} solid solutions. Chemical composition range and flux crystal growth

Energy Technology Data Exchange (ETDEWEB)

Ivanov, V.A. [N.I. Lobachevsky State University of Nizhni Novgorod, Nizhni Novgorod, 603950 (Russian Federation); Marychev, M.O., E-mail: marychev@yandex.ru [N.I. Lobachevsky State University of Nizhni Novgorod, Nizhni Novgorod, 603950 (Russian Federation); Andreev, P.V.; Lykov, V.A.; Faddeev, M.A. [N.I. Lobachevsky State University of Nizhni Novgorod, Nizhni Novgorod, 603950 (Russian Federation); Koseva, I. [Bulgarian Academy of Science, Institute of General and Inorganic Chemistry, BU-1113 Sofia (Bulgaria); Nikolov, V. [N.I. Lobachevsky State University of Nizhni Novgorod, Nizhni Novgorod, 603950 (Russian Federation)

2015-11-01

A series of Ca{sub 2−x}Li{sub 2x}GeO{sub 4} specimens with 0 < 2x < 2, were synthesized by the classical solid state method. X-ray analysis revealed that for 0 < 2x < 0.6 only Ca{sub 2−x}Li{sub 2x}GeO{sub 4} solid solutions of Ca{sub 2}GeO{sub 4} structure crystallized. The cell parameters of these solid solutions linearly decreased upon increasing the lithium concentration, which means that the solutions are in accordance with the Vegard's law. For 2x > 0.6 the specimens contained two phases: (i) Ca{sub 2−x}Li{sub 2x}GeO{sub 4} solid solutions with maximum lithium concentration approximately equal to that for 2x = 0.6 and minimum values of the cell parameters and (ii) Li{sub 2}CaGeO{sub 4} phase. Li{sub 2}O·MoO{sub 3}–Ca{sub 2}GeO{sub 4} high-temperature solutions were used to grow Ca{sub 2−x}Li{sub 2x}GeO{sub 4} solid solutions and Li{sub 2}CaGeO{sub 4} single crystals by the high temperature solution (flux) method. Li{sub 2}CaGeO{sub 4} crystals were grown in the concentration range 8–26 wt. % Ca{sub 2}GeO{sub 4} in the temperature range 830–980 °C. Crystals with chemical compositions of the Ca{sub 2−x}Li{sub 2x}GeO{sub 4} solid solutions with different Li concentrations were grown in the concentration range 26–40 wt. % Ca{sub 2}GeO{sub 4} in the temperature range 980–1090 °C. - Highlights: • Ca{sub 2−x}Li{sub 2x}GeO{sub 4} solid solutions are established for the first time. • The Li concentration range into the solutions is between 0 and 0.6. • The solid solutions are in accordance to Vegard's law. • Suitable solutions are found out for Ca{sub 2−x}Li{sub 2x}GeO{sub 4} and Li{sub 2}CaGeO{sub 4} crystal growth.

High-Yield Production of Levulinic Acid from Pretreated Cow Dung in Dilute Acid Aqueous Solution

Directory of Open Access Journals (Sweden)

Jialei Su

2017-02-01

Full Text Available Agricultural waste cow dung was used as feedstock for the production of a high value–added chemical levulinic acid (LA in dilute acid aqueous solutions. A high LA yield of 338.9 g/kg was obtained from the pretreated cow dung, which was much higher than that obtained from the crude cow dung (135 g/kg, mainly attributed to the breakage of the lignin fraction in the lignocellulose structure of the cow dung by potassium hydroxide (KOH pretreatment, and thus enhanced the accessibility of cow dung to the acid sites in the catalytic reaction. Meanwhile, another value-added chemical formic acid could be obtained with a yield of ca. 160 g/kg in the process, implying a total production of ca. 500 g/kg yield for LA and formic acid from the pretreated cow dung with the proposed process. The developed process was shown to be tolerant to high initial substrate loading with a satisfied LA yield. This work provides a promising strategy for the value-increment utilization of liglocellulosic agricultural residues.

Correlation of Solid State and Solution Coordination Numbers with Infrared Spectroscopy in Five-, Six-, and Eight-Coordinate Transition Metal Complexes of DOTAM.

Science.gov (United States)

Nagata, Maika K C T; Brauchle, Paul S; Wang, Sen; Briggs, Sarah K; Hong, Young Soo; Laorenza, Daniel W; Lee, Andrea G; Westmoreland, T David

2016-08-16

Three new DOTAM (1,4,7,10-tetrakis(acetamido)-1,4,7,10-tetraazacyclododecane) complexes have been synthesized and characterized by X-ray crystallography: [Co(DOTAM)]Cl 2 •3H 2 O, [Ni(DOTAM)]Cl 2 •4H 2 O, and [Cu(DOTAM)](ClO 4 ) 2 •H 2 O. Solid state and solution IR spectroscopic features for a series of [M(DOTAM)] 2+ complexes (M=Mn, Co, Cu, Ni, Ca, Zn) correlate with solid state and solution coordination numbers. [Co(DOTAM)] 2+ , [Ni(DOTAM)] 2+ , and [Zn(DOTAM)] 2+ are demonstrated to be six-coordinate in both the solid state and in solution, while [Mn(DOTAM)] 2+ and [Ca(DOTAM)] 2+ are eight-coordinate in the solid state and remain so in solution. [Cu(DOTAM)] 2+ , which is five-coordinate by X-ray crystallography, is shown to increase its coordination number in solution to six-coordinate.

Coupling between magnetic and optical properties of stable Au-Fe solid solution nanoparticles

Energy Technology Data Exchange (ETDEWEB)

De Julian Fernandez, C; Novak, R L; Bogani, L; Caneschi, A [INSTM RU at the Department of Chemistry of the University of Firenze, via della Lastruccia 3, 50019 Sesto Fiorentino (Italy); Mattei, G; Mazzoldi, P [Department of Physics, CNISM and University of Padova, via Marzolo 8, 35131 Padova (Italy); Paz, E; Palomares, F J [Instituto de Ciencia de Materiales de Madrid (CSIC), Cantoblanco, 28049 Madrid (Spain); Cavigli, L, E-mail: cesar.dejulian@unifi.it [Department of Physics-LENS, University of Florence, via Sansone 1, 50019 Sesto Fiorentino (Italy)

2010-04-23

Au-Fe nanoparticles constitute one of the simplest prototypes of a multifunctional nanomaterial that can exhibit both magnetic and optical (plasmonic) properties. This solid solution, not feasible in the bulk phase diagram in thermal equilibrium, can be formed as a nanostructure by out-of-equilibrium processes. Here, the novel magnetic, optical and magneto-optical properties of ion-implanted Au-Fe solid solution nanoparticles dispersed in a SiO{sub 2} matrix are investigated and correlated. The surface plasmon resonance of the Au-Fe nanoparticles with almost equicomposition is strongly damped when compared to pure Au and to Au-rich Au-Fe nanoparticles. In all cases, the Au atoms are magnetically polarized, as measured by x-ray magnetic circular dichroism, and ferromagnetically coupled with Fe atoms. Although the chemical stability of Au-Fe nanoparticles is larger than that of Fe nanoparticles, both the magnetic moment per Fe atom and the order temperature are smaller. These results suggest that electronic and magnetic properties are more influenced by the hybridization of the electronic bands in the Au-Fe solid solution than by size effects. On the other hand, the magneto-optical transitions allowed in the vis-nIR spectral regions are very similar. In addition, we also observe, after studying the properties of thermally treated samples, that the Au-Fe alloy is stabilized, not by surface effects, but by the combination of the out-of-equilibrium nature of the ion implantation technique and by changes in the properties due to size effects.

Coupling between magnetic and optical properties of stable Au-Fe solid solution nanoparticles

International Nuclear Information System (INIS)

De Julian Fernandez, C; Novak, R L; Bogani, L; Caneschi, A; Mattei, G; Mazzoldi, P; Paz, E; Palomares, F J; Cavigli, L

2010-01-01

Au-Fe nanoparticles constitute one of the simplest prototypes of a multifunctional nanomaterial that can exhibit both magnetic and optical (plasmonic) properties. This solid solution, not feasible in the bulk phase diagram in thermal equilibrium, can be formed as a nanostructure by out-of-equilibrium processes. Here, the novel magnetic, optical and magneto-optical properties of ion-implanted Au-Fe solid solution nanoparticles dispersed in a SiO 2 matrix are investigated and correlated. The surface plasmon resonance of the Au-Fe nanoparticles with almost equicomposition is strongly damped when compared to pure Au and to Au-rich Au-Fe nanoparticles. In all cases, the Au atoms are magnetically polarized, as measured by x-ray magnetic circular dichroism, and ferromagnetically coupled with Fe atoms. Although the chemical stability of Au-Fe nanoparticles is larger than that of Fe nanoparticles, both the magnetic moment per Fe atom and the order temperature are smaller. These results suggest that electronic and magnetic properties are more influenced by the hybridization of the electronic bands in the Au-Fe solid solution than by size effects. On the other hand, the magneto-optical transitions allowed in the vis-nIR spectral regions are very similar. In addition, we also observe, after studying the properties of thermally treated samples, that the Au-Fe alloy is stabilized, not by surface effects, but by the combination of the out-of-equilibrium nature of the ion implantation technique and by changes in the properties due to size effects.

Coupling between magnetic and optical properties of stable Au-Fe solid solution nanoparticles

Science.gov (United States)

de Julián Fernández, C.; Mattei, G.; Paz, E.; Novak, R. L.; Cavigli, L.; Bogani, L.; Palomares, F. J.; Mazzoldi, P.; Caneschi, A.

2010-04-01

Au-Fe nanoparticles constitute one of the simplest prototypes of a multifunctional nanomaterial that can exhibit both magnetic and optical (plasmonic) properties. This solid solution, not feasible in the bulk phase diagram in thermal equilibrium, can be formed as a nanostructure by out-of-equilibrium processes. Here, the novel magnetic, optical and magneto-optical properties of ion-implanted Au-Fe solid solution nanoparticles dispersed in a SiO2 matrix are investigated and correlated. The surface plasmon resonance of the Au-Fe nanoparticles with almost equicomposition is strongly damped when compared to pure Au and to Au-rich Au-Fe nanoparticles. In all cases, the Au atoms are magnetically polarized, as measured by x-ray magnetic circular dichroism, and ferromagnetically coupled with Fe atoms. Although the chemical stability of Au-Fe nanoparticles is larger than that of Fe nanoparticles, both the magnetic moment per Fe atom and the order temperature are smaller. These results suggest that electronic and magnetic properties are more influenced by the hybridization of the electronic bands in the Au-Fe solid solution than by size effects. On the other hand, the magneto-optical transitions allowed in the vis-nIR spectral regions are very similar. In addition, we also observe, after studying the properties of thermally treated samples, that the Au-Fe alloy is stabilized, not by surface effects, but by the combination of the out-of-equilibrium nature of the ion implantation technique and by changes in the properties due to size effects.

Atomic mean-square displacements and the critical-voltage effect in cubic solid solutions

International Nuclear Information System (INIS)

Shirley, C.G.; Fisher, R.M.

1979-01-01

The critical-voltage phenomena observed in high-voltage electron microscope images of bend contours as well as in corresponding Kikuchi or convergent-beam diffraction patterns provide sensitive methods of determining submicroscopic alloy parameters such as Debye temperatures, short-range order, and atomic scattering factors. Only a very limited number of critical voltages can be observed in metal crystals in the voltage range usually available, 100 to 1200 kV, so that quantitative interpretation of the data must be based on a few-parameter model which incorporates all the pertinent factors. A satisfactory two-parameter model has been developed which can be used to interpret or compute the critical voltages of substitutional solid solutions as functions of composition, temperature and short-range order. In the alloy systems Fe-Cr, Ni-Au, Cu-Au and Cu-Al, sufficient critical voltage data are available to derive the model parameters which pertain to atomic bonding in the lattice. In addition to atomic scattering amplitudes, the critical voltage depends strongly on the atomic mean-square displacements. The static contribution to the mean-square displacements is large in alloys with large atomic-radius disparity, and is especially sensitive to short-range order in f.c.c. solid solutions. Well-defined best estimates for the model parameters are used to predict the critical voltage and its sensitivity to composition, temperature and short-range order for a large number of solid solutions. Systems for which critical-voltage studies may be of considerable interest are indicated. (author)

Evaluation of two different HEDP content kits: Stability study against dilution both in vivo and in vitro

International Nuclear Information System (INIS)

Inoue, O.; Ikeda, I.; Kurata, K.

1982-01-01

Two different HEDP content kits (Kit A, HEDP: 1 mg, SnCl 2 x 2H 2 O: 0.5 mg; and Kit B, HEDP: 10 mg, SnCl 2 x 2H 2 O: 0.5 mg) were evaluated for their stability against dillution. Sup(99m)Tc-HEDP solutions prepared from these two kits were diluted from 10 to 6000 fold with 0.9% NaCl solution just before evaluation both in vivo and in vitro. In the case of Kit A, significant soft tissue uptake in vivo and released free pertechnetate in vitro were observed by diluting the sup(99m)Tc-HEDP solution. On the other hand, sup(99m)Tc-HEDP prepared from Kit B was found to be sufficiently stable against dilution. The stability after preparation of each diluted sup(99m)-HEDP was also greatly affected by its HEDP concentration. Preliminary analysis of absorption spectra for each 99 Tc-HEDP indicated the possibility of two different sup(99m)Tc-HEDP complex formation by varied HEDP concentration. These results indicated that a cold reagent like Kit A might cause a higher soft tissue uptake due to its dilution in vivo during a clinical study for bone scanning. (orig.) [de

Xylanase supplementation on enzymatic saccharification of dilute acid pretreated poplars at different severities

Science.gov (United States)

Chao Zhang; Xinshu Zhuang; Zhao Jiang Wang; Fred Matt; Franz St. John; J.Y. Zhu

2013-01-01

Three pairs of solid substrates from dilute acid pretreatment of two poplar wood samples were enzymatically hydrolyzed by cellulase preparations supplemented with xylanase. Supplementation of xylanase improved cellulose saccharification perhaps due to improved cellulose accessibility by xylan hydrolysis. Total xylan removal directly affected enzymatic cellulose...

Ionic conductivity of LISICON solid solutions, Li 2+2 xZn 1- xGeO 4

Science.gov (United States)

Bruce, P. G.; West, A. R.

1982-10-01

The conductivity of LISICON γII-type solid solutions of general formula Li 2+2 xZn 1- xGeO 4 (-0.36 class of Li + ion conductors, was measured over the temperature range ˜25 to 300°C. Conductivities appear to be very composition dependent near the stoichiometric composition x = 0, but less so in the range 0.15 ≲ x ≲ 0.87. It is shown that interstitial Li + ions rather than cation vacancies give rise to high conductivities. The solid electrolyte properties and possible applications of the solid solutions are evaluated. The LISICON composition, x = 0.75, decomposes readily above ˜300°C by precipitation of Li 4GeO 4, thereby limiting its possible usefulness, but compositions in the range x = 0.45 to 0.55 appear to be stable at all temperatures. However, irreversible decreases in conductivity (aging effects) occur on annealing, even at room temperature. The conductivity data of quenched samples give linear Arrhenius plots, but with anomalously high prefactors, over the range ˜25 to 130°C; at higher temperatures reversible changes of slope to lower activation energies occur. A variety of minor polymorphic transitions occur on annealing γII solid solutions below ˜300°C and their relationship to the conductivity was also determined.

Improved creep strength of nickel-base superalloys by optimized γ/γ′ partitioning behavior of solid solution strengthening elements

International Nuclear Information System (INIS)

Pröbstle, M.; Neumeier, S.; Feldner, P.; Rettig, R.; Helmer, H.E.; Singer, R.F.; Göken, M.

2016-01-01

Solid solution strengthening of the γ matrix is one key factor for improving the creep strength of single crystal nickel-base superalloys at high temperatures. Therefore a strong partitioning of solid solution hardening elements to the matrix is beneficial for high temperature creep strength. Different Rhenium-free alloys which are derived from CMSX-4 are investigated. The alloys have been characterized regarding microstructure, phase compositions as well as creep strength. It is found that increasing the Titanium (Ti) as well as the Tungsten (W) content causes a stronger partitioning of the solid solution strengtheners, in particular W, to the γ phase. As a result the creep resistance is significantly improved. Based on these ideas, a Rhenium-free alloy with an optimized chemistry regarding the partitioning behavior of W is developed and validated in the present study. It shows comparable creep strength to the Rhenium containing second generation alloy CMSX-4 in the high temperature / low stress creep regime and is less prone to the formation of deleterious topologically close packed (TCP) phases. This more effective usage of solid solution strengtheners can enhance the creep properties of nickel-base superalloys while reducing the content of strategic elements like Rhenium.

Analysis of several hazardous conditions for large transfer and back-dilution sequences in Tank 241-SY-101

International Nuclear Information System (INIS)

CW Stewart; LA Mahoney; WB Barton

2000-01-01

The first transfer of 89 kgal of waste and back-dilution of 61 kgal of water in Hanford Tank 241-SY-101 was accomplished December 18--20, 1999. Limits were placed on the transfer and back-dilution volumes because of concerns about potential gas release, crust sinking, and degradation of mixer pump performance. Additional transfers and back-dilutions are being planned that will bring the total to 500 kgal, which should dissolve a large fraction of the solids in the tank and dilute it well beyond the point where significant gas retention can occur. This report provides the technical bases for removing the limits on transfer and back-dilution volume by evaluating the potential consequences of several postulated hazardous conditions in view of the results of the first campaign and results of additional analyses of waste behavior

Analysis of several hazardous conditions for large transfer and back-dilution sequences in Tank 241-SY-101

Energy Technology Data Exchange (ETDEWEB)

CW Stewart; LA Mahoney; WB Barton

2000-01-28

The first transfer of 89 kgal of waste and back-dilution of 61 kgal of water in Hanford Tank 241-SY-101 was accomplished December 18--20, 1999. Limits were placed on the transfer and back-dilution volumes because of concerns about potential gas release, crust sinking, and degradation of mixer pump performance. Additional transfers and back-dilutions are being planned that will bring the total to 500 kgal, which should dissolve a large fraction of the solids in the tank and dilute it well beyond the point where significant gas retention can occur. This report provides the technical bases for removing the limits on transfer and back-dilution volume by evaluating the potential consequences of several postulated hazardous conditions in view of the results of the first campaign and results of additional analyses of waste behavior.

A decontamination system for chemical weapons agents using a liquid solution on a solid sorbent

International Nuclear Information System (INIS)

Waysbort, Daniel; McGarvey, David J.; Creasy, William R.; Morrissey, Kevin M.; Hendrickson, David M.; Durst, H. Dupont

2009-01-01

A decontamination system for chemical warfare agents was developed and tested that combines a liquid decontamination reagent solution with solid sorbent particles. The components have fewer safety and environmental concerns than traditional chlorine bleach-based products or highly caustic solutions. The liquid solution, based on Decon Green TM , has hydrogen peroxide and a carbonate buffer as active ingredients. The best solid sorbents were found to be a copolymer of ethylene glycol dimethacrylate and n-lauryl methacrylate (Polytrap 6603 Adsorber); or an allyl methacrylate cross-linked polymer (Poly-Pore E200 Adsorber). These solids are human and environmentally friendly and are commonly used in cosmetics. The decontaminant system was tested for reactivity with pinacolyl methylphosphonofluoridate (Soman, GD), bis(2-chloroethyl)sulfide (Mustard, HD), and S-(2-diisopropylaminoethyl) O-ethyl methylphosphonothioate (VX) by using NMR Spectroscopy. Molybdate ion (MoO 4 -2 ) was added to the decontaminant to catalyze the oxidation of HD. The molybdate ion provided a color change from pink to white when the oxidizing capacity of the system was exhausted. The decontaminant was effective for ratios of agent to decontaminant of up to 1:50 for VX (t 1/2 ≤ 4 min), 1:10 for HD (t 1/2 1/2 < 2 min). The vapor concentrations of GD above the dry sorbent and the sorbent with decontamination solution were measured to show that the sorbent decreased the vapor concentration of GD. The E200 sorbent had the additional advantage of absorbing aqueous decontamination solution without the addition of an organic co-solvent such as isopropanol, but the rate depended strongly on mixing for HD

Decay property of regularity-loss type for solutions in elastic solids with voids

KAUST Repository

Djouamai, Leila; Said-Houari, Belkacem

2014-01-01

In this paper, we consider the Cauchy problem for a system of elastic solids with voids. First, we show that a linear porous dissipation leads to decay rates of regularity-loss type of the solution. We show some decay estimates for initial data in Hs(R)∩L1(R). Furthermore, we prove that by restricting the initial data to be in Hs(R)∩L1,γ(R) and γ. ∈. [0, 1], we can derive faster decay estimates of the solution. Second, we show that by adding a viscoelastic damping term, then we gain the regularity of the solution and obtain the optimal decay rate. © 2013 Elsevier Ltd.

Dilution Ratios for HB Line Phase I Eductor System

International Nuclear Information System (INIS)

Steimke, J.L.

2002-01-01

HB Line Phase I product transfer includes an eductor which transfers liquid from Product Hold Tank (PHT) RT-33 or RT-34 to Tank 11.1. The eductor also dilutes the liquid from the PHT with eductant. Dilution must be reliably controlled because of criticality concerns with H Canyon Tanks. The eductor system, which contains a 1 inch Model 264 Schutte and Koerting eductor, was previously modeled [1] in 1998 and dilution ratios were calculated for different flow restrictors, eductant pressures and densities for the eductant and the contents of the PHT. The previous calculation was performed using spreadsheet software no longer supported at SRS. For the previous work dilution ratio was defined as the volume of eductant consumed divided by volume of PHT contents transferred. Since 1998 HB Line Engineering has changed the definition of dilution ratio to the total volume of liquid, eductant consumed plus the volume of PHT liquid transferred, divided by the volume of PHT liquid transferred. The 1998 base case calculation was for a restrictor diameter of 0.334 inches, an eductant supply pressure of 15 psig, full PHT, an eductant specific gravity of 1.385 and a PHT density of 1.015. The base case dilution ratio calculated in 1998 using the current definition was 3.52. After accounting for uncertainty the minimum dilution ratio decreased to 3.23. In 2001 HB Line Engineering requested that the calculation be repeated for a manganous nitrate solution eductant and also a process water eductant. The other conditions were the same as for the 1998 calculation. The objective of this report is to document the calculations and the results

Selective on site separation and detection of molecules in diluted solutions with super-hydrophobic clusters of plasmonic nanoparticles

KAUST Repository

Gentile, Francesco T.; Coluccio, Maria Laura; Proietti Zaccaria, Remo; Francardi, Marco; Cojoc, Gheorghe; Perozziello, Gerardo; Raimondo, Raffaella; Candeloro, Patrizio; Di Fabrizio, Enzo M.

2014-01-01

Super-hydrophobic surfaces are bio-inspired interfaces with a superficial texture that, in its most common evolution, is formed by a periodic lattice of silicon micro-pillars. Similar surfaces reveal superior properties compared to conventional flat surfaces, including very low friction coefficients. In this work, we modified meso-porous silicon micro-pillars to incorporate networks of metal nano-particles into the porous matrix. In doing so, we obtained a multifunctional-hierarchical system in which (i) at a larger micrometric scale, the super-hydrophobic pillars bring the molecules dissolved in an ultralow-concentration droplet to the active sites of the device, (ii) at an intermediate meso-scale, the meso-porous silicon film adsorbs the low molecular weight content of the solution and, (iii) at a smaller nanometric scale, the aggregates of silver nano-particles would measure the target molecules with unprecedented sensitivity. In the results, we demonstrated how this scheme can be utilized to isolate and detect small molecules in a diluted solution in very low abundance ranges. The presented platform, coupled to Raman or other spectroscopy techniques, is a realistic candidate for the protein expression profiling of biological fluids. © 2014 the Partner Organisations.

A Moessbauer study on the photolysis of potassium trisoxalatoferrate(III) in solid and solutions

International Nuclear Information System (INIS)

Sato, H.; Tominaga, T.

1977-01-01

The photolysis of potassium trisoxalatoferrate(III) in solid and aqueous solutions was studied by Moessbauer spectroscopy. A ferrous species was mainly detected as an intermediate product in the photoirradiated solutions. A tentative mechanism was proposed for the overall reactions in and after the photolysis of this compound. The Moessbauer spectra were measured with a Hitachi AA-40 or Shimadzu MEG-2 Moessbauer spectrometer against Co-57 in copper foil. Acrylic holders (32 mm in diameter) were used for measurements of solutions: the irradiated solution was quickly frozen before measurement by adding it dropwise into the acrylic holder which had been cooled with liquid nitrogen or dry-ice. (T.I.)

Photoelectrochemical properties of CdSesub(x)Tesub(1-x) semiconducting solid solutions

International Nuclear Information System (INIS)

Kolbasov, G.Ya.; Karpov, I.I.; Pavelets, A.M.; Khanat, L.N.

1985-01-01

Photoelectrochemical properties of polycrystalline films of solid solutions CdSesub(x)Tesub(1-x) at x=0.5-0.8 are studied. Films from 5 to 30 μm thickness had hexagonal or mixed cubic and hexogonal structures depending on the compositions. All compositions had the electron type of conductivity. Alkali solutions of Na 2 S and S were used as electrolyte. Polarization characteristics of the CdSesub(0.5)Tesub(0.5) photoelectrode, curves of spectral dependence of photo electrochemical current and of the changes of photo-e.m.f. on electrode potential are plotted

Cadmium determination in natural waters at the limit imposed by European legislation by isotope dilution and TiO2 solid-phase extraction.

Science.gov (United States)

García-Ruiz, Silvia; Petrov, Ivan; Vassileva, Emilia; Quétel, Christophe R

2011-11-01

The cadmium content in surface water is regulated by the last European Water Framework Directive to a maximum between 0.08 and 0.25 μg L(-1) depending on the water type and hardness. Direct measurement of cadmium at this low level is not straightforward in real samples, and we hereby propose a validated method capable of addressing cadmium content below μg L(-1) level in natural water. It is based on solid-phase extraction using TiO(2) nanoparticles as solid sorbent (0.05 g packed in mini-columns) to allow the separation and preconcentration of cadmium from the sample, combined to direct isotope dilution and detection by inductively coupled plasma mass spectrometry (ID-ICP-MS). The extraction setup is miniaturised and semi-automated to reduce risks of sample contamination and improve reproducibility. Procedural blanks for the whole measurement process were 5.3 ± 2.8 ng kg(-1) (1 s) for 50 g of ultrapure water preconcentrated ten times. Experimental conditions influencing the separation (including loading pH, sample flow rates, and acid concentration in the eluent) were evaluated. With isotope dilution the Cd recovery rate does not have to be evaluated carefully. Moreover, the mathematical model associated to IDMS is known, and provides transparency for the uncertainty propagation. Our validation protocol was in agreement with guidelines of the ISO/IEC 17025 standard (chapter 5.4.5). Firstly, we assessed the experimental factors influencing the final result. Secondly, we compared the isotope ratios measured after our separation procedure to the reference values obtained with a different protocol for the digested test material IMEP-111 (mineral feed). Thirdly, we analysed the certified reference material BCR-609 (groundwater). Finally, combined uncertainties associated to our results were estimated according to ISO-GUM guidelines (typically, 3-4% k = 2 for a cadmium content of around 100 ng kg(-1)). We applied the developed method to the groundwater and wastewater

Influence of lanthanum on the physico-chemical properties of solid solutions GeS0.5Se0.5

International Nuclear Information System (INIS)

Murquzov, M.I.; Alekperov, A.S.; Bayramov, R.B.

2010-01-01

By the methods of physical-chemical analysis (X-ray, MSA, as well as measurement of microhardness and density determination) the influence of La on the physico-chemical properties of solid solutions (GeS 0 .5Se 0 .5) 1 -x(La) x was studied and its microdiagram was plotted. At room temperature the GeS 0 .5Se 0 .5 based solid solution extent 4 at. percent of La. The dependence of lanthane microhardness was studied

Structural studies of TiC1−xOx solid solution by Rietveld refinement and first-principles calculations

International Nuclear Information System (INIS)

Jiang, Bo; Hou, Na; Huang, Shanyan; Zhou, Gege; Hou, Jungang; Cao, Zhanmin; Zhu, Hongmin

2013-01-01

The lattice parameters, structural stability and electronic structure of titanium oxycarbides (TiC 1−x O x , 0≤x≤1) solid solution were investigated by Rietveld refinement and first-principles calculations. Series of TiC 1−x O x were precisely synthesized by sintering process under the vacuum. Rietveld refinement results of XRD patterns show the properties of continuous solid solution in TiC 1−x O x over the whole composition range. The lattice parameters vary from 0.4324 nm to 0.4194 nm decreasing with increasing oxygen concentration. Results of first-principles calculations reveal that the disorder C/O structure is stable than the order C/O structure. Further investigations of the vacancy in Ti 1−Va (C 1−x O x ) 1−Va solid solution present that the structure of vacancy segregated in TiO-part is more stable than the disorder C/O structure, which can be ascribed to the Ti–Ti bond across O-vacancy and the charge redistributed around Ti-vacancy via the analysis of the electron density difference plots and PDOS. - Graphical abstract: XRD of series of titanium oxycarbides (TiC 1−x O x , 0≤x≤1) solid solution prepared by adjusting the proportion of TiO in the starting material. Highlights: • Titanium oxycarbides were obtained by sintering TiO and TiC under carefully controlled conditions. • Rietveld refinement results show continuous solid solution with FCC structure in TiC 1−x O x . • The disorder C/O structure is stable than the order C/O structure. • Introduction of vacancy segregated in TiO-part is more stable than disorder C/O structure. • Ti–Ti bond across O-vacancy and the charge redistributed around Ti-vacancy enhance structural stability

Preparation and X-ray diffraction characterization of Th1-xBixO2-0.5x (where x= 0 to 0.5) solid solutions

International Nuclear Information System (INIS)

Kanrar, Buddhadev; Misra, N.L.

2015-01-01

Solid solutions of ThO 2 and Bi 2 O 3 were prepared by solid state reactions of these oxides. X-ray diffraction studies indicated that Bi +3 up to 50 at% can be dissolved in ThO 2 lattice. Rietveld refinement of the XRD patterns indicated single phase solid solutions up to 50 atom% of Bi +3 in ThO 2 lattice. The cell parameters of the solid solutions were found to decrease with increasing amount of Bi +3 in the lattice. (author)

Solubility of jarosite solid solutions precipitated from acid mine waters, Iron Mountain, California

Science.gov (United States)

Alpers, Charles N.; Nordstrom, D. Kirk; Ball, J.W.

1989-01-01

Because of the common occurrence of 15 to 25 mole percent hydronium substitution on the alkali site in jarosites, it is necessary to consider the hydronium content of jarosites in any attempt at rigorous evaluation of jarosite solubility or of the saturation state of natural waters with respect to jarosite. A Gibbs free energy of 3293.5±2.1 kJ mol-1 is recommended for a jarosite solid solution of composition K.77Na.03(H3O).20Fe3(SO4)2(OH)6. Solubility determinations for a wider range of natural and synthetic jarosite solid solutions will be necessary to quantify the binary and ternary mixing parameters in the (K-Na-H3O) system. In the absence of such studies, molar volume data for endmember minerals indicate that the K-H3O substitution in jarosite is probably closer to ideal mixing than either the Na-K or Na-H3O substitution.

Molar mass, radius of gyration and second virial coefficient from new static light scattering equations for dilute solutions: application to 21 (macro)molecules.

Science.gov (United States)

Illien, Bertrand; Ying, Ruifeng

2009-05-11

New static light scattering (SLS) equations for dilute binary solutions are derived. Contrarily to the usual SLS equations [Carr-Zimm (CZ)], the new equations have no need for the experimental absolute Rayleigh ratio of a reference liquid and solely rely on the ratio of scattered intensities of solutions and solvent. The new equations, which are based on polarizability equations, take into account the usual refractive index increment partial differential n/partial differential rho(2) complemented by the solvent specific polarizability and a term proportional to the slope of the solution density rho versus the solute mass concentration rho(2) (density increment). Then all the equations are applied to 21 (macro)molecules with a wide range of molar mass (0.2equations clearly achieve a better agreement with supplier M values. For macromolecules (M>500 kg mol(-1)), for which the scattered intensity is no longer independent of the scattering angle, the new equations give the same value of the radius of gyration as the CZ equation and consistent values of the second virial coefficient.

Theoretical multi-physics approaches to solid-solution strengthening of Al

Energy Technology Data Exchange (ETDEWEB)

Ma, Duancheng; Friak, Martin; Raabe, Dierk; Neugebauer, Joerg [Max-Planck-Institut fuer Eisenforschung GmbH, Duesseldorf (Germany)

2009-07-01

The strengthening of soft metallic materials has a long tradition and is an important metallurgical topic since the time when ancient smiths forged the first swords. Intense materials research revealed a combination of three mechanisms as decisive for solid-solution strengthening phenomena: (i) the size mismatch of components (Mott and Nabarro's parelastic concept), (ii) the elastic modulus mismatch of atoms (Fleischer's dielastic contribution), and (iii) the concentration of solutes (statistical concept of Friedel and Labusch). Combining density functional theory calculations and linear-elasticity theory, the key parameters that are essential for the classical strengthening theories are determined in order to test them and identify their possible validity limits. The strengthening of fcc aluminium is chosen as an example and a series of binary systems Al-X (with X=Ca,Sr,Ir,Li,Mg,Cu) was considered. Comparing our results with those obtained by applying classical theories we find clear deviations. These deviations originate from non-classical lattice distortions due to the size mismatch of solute atoms in their first coordination shells.

Radiolysis of paracetamol in dilute aqueous solution

International Nuclear Information System (INIS)

Szabó, László; Tóth, Tünde; Homlok, Renáta; Takács, Erzsébet; Wojnárovits, László

2012-01-01

Using radiolytic experiments hydroxyl radical (main reactant in advanced oxidation processes) was shown to effectively destroy paracetamol molecules. The basic reaction is attachment to the ring. The hydroxy-cyclohexadienyl radical produced in the further reactions may transform to hydroxylated paracetamol derivatives or to quinone type molecules and acetamide. The initial efficiency of aromatic ring destruction in the absence of dissolved O 2 is c.a. 10%. The efficiency is 2–3 times higher in the presence of O 2 due to its reaction with intermediate hydroxy-cyclohexadienyl radical and the subsequent ring destruction reactions through peroxi radical. Upon irradiation the toxicity of solutions at low doses increases with the dose and then at higher doses it decreases. This is due to formation of compounds with higher toxicity than paracetamol (e.g. acetamide, hidroquinone). These products, however, are highly sensitive to irradiation and degrade easily. - Highlights: ► Paracetamol is easily degraded in aqueous solution by low dose irradiation. ► Main degradation products are hydroxylated molecules, acetamide and hydroquinone. ► Toxicity of solutions goes through a maximum as a function of dose.

Radiolysis of paracetamol in dilute aqueous solution

Energy Technology Data Exchange (ETDEWEB)

Szabo, Laszlo [Institute of Isotopes, Hungarian Academy of Sciences, Budapest (Hungary); Budapest University of Technology and Economics, Budapest (Hungary); Toth, Tuende [Budapest University of Technology and Economics, Budapest (Hungary); Homlok, Renata [Institute of Isotopes, Hungarian Academy of Sciences, Budapest (Hungary); Takacs, Erzsebet [Institute of Isotopes, Hungarian Academy of Sciences, Budapest (Hungary); Wojnarovits, Laszlo [Institute of Isotopes, Hungarian Academy of Sciences, Budapest (Hungary)

2012-09-15

Using radiolytic experiments hydroxyl radical (main reactant in advanced oxidation processes) was shown to effectively destroy paracetamol molecules. The basic reaction is attachment to the ring. The hydroxy-cyclohexadienyl radical produced in the further reactions may transform to hydroxylated paracetamol derivatives or to quinone type molecules and acetamide. The initial efficiency of aromatic ring destruction in the absence of dissolved O{sub 2} is c.a. 10%. The efficiency is 2-3 times higher in the presence of O{sub 2} due to its reaction with intermediate hydroxy-cyclohexadienyl radical and the subsequent ring destruction reactions through peroxi radical. Upon irradiation the toxicity of solutions at low doses increases with the dose and then at higher doses it decreases. This is due to formation of compounds with higher toxicity than paracetamol (e.g. acetamide, hidroquinone). These products, however, are highly sensitive to irradiation and degrade easily. - Highlights: Black-Right-Pointing-Pointer Paracetamol is easily degraded in aqueous solution by low dose irradiation. Black-Right-Pointing-Pointer Main degradation products are hydroxylated molecules, acetamide and hydroquinone. Black-Right-Pointing-Pointer Toxicity of solutions goes through a maximum as a function of dose.

Crystal Fields in Dilute Rare-Earth Metals Obtained from Magnetization Measurements on Dilute Rare-Earth Alloys

DEFF Research Database (Denmark)

Touborg, P.; Høg, J.

1974-01-01

Crystal field parameters of Tb, Dy, and Er in Sc, Y, and Lu are summarized. These parameters are obtained from magnetization measurements on dilute single crystals, and successfully checked by a number of different methods. The crystal field parameters vary unpredictably with the rare-earth solute....... B40, B60, and B66 are similar in Y and Lu. Crystal field parameters for the pure metals Tb, Dy, and Er are estimated from the crystal fields in Y and Lu....

Phase transitions of single polymer chains and of polymer solutions: insights from Monte Carlo simulations

International Nuclear Information System (INIS)

Binder, K; Paul, W; Strauch, T; Rampf, F; Ivanov, V; Luettmer-Strathmann, J

2008-01-01

The statistical mechanics of flexible and semiflexible macromolecules is distinct from that of small molecule systems, since the thermodynamic limit can also be approached when the number of (effective) monomers of a single chain (realizable by a polymer solution in the dilute limit) is approaching infinity. One can introduce effective attractive interactions into a simulation model for a single chain such that a swollen coil contracts when the temperature is reduced, until excluded volume interactions are effectively canceled by attractive forces, and the chain conformation becomes almost Gaussian at the theta point. This state corresponds to a tricritical point, as the renormalization group theory shows. Below the theta temperature a fluid globule is predicted (at nonzero concentration then phase separation between dilute and semidilute solutions occurs), while at still lower temperature a transition to a solid phase (crystal or glass) occurs. Monte Carlo simulations have shown, however, that the fluid globule phase may become suppressed, when the range of the effective attractive forces becomes too short, with the result that a direct (ultimately first-order) transition from the swollen coil to the solid occurs. This behavior is analogous to the behavior of colloidal particles with a very short range of attractive forces, where liquid-vapor-type phase separation may be suppressed. Analogous first-order transitions from swollen coils to dense rodlike or toroidal structures occur for semiflexible polymers. Finally, the modifications of the behavior discussed when the polymers are adsorbed at surfaces are also mentioned, and possible relations to wetting behavior of polymer solutions are addressed.

Separation of compounds with multiple -OH groups from dilute aqueous solutions via complexation with organoboronate

Energy Technology Data Exchange (ETDEWEB)

Chow, Tina Kuo Fung [Univ. of California, Berkeley, CA (United States)

1992-05-01

The complexing extractant agent investigated in this work is 3-nitrophenylboronic acid (NPBA) in its anionic form (NPB). NPBA and Aliquat 336 (quaternary amine) is dissolved in 2-ethyl-l-hexanol, and the extractant is contacted with aq. NaOH. Solutes investigated were 1,2-propanediol, glycerol, fructose, sorbitol and lactic acid. Batch extraction experiments were performed at 25°C. Partition coefficients, distribution ratios and loadings are reported for varying concentrations of solute and NPB. All solutes complexed with NPB^-, with all complexes containing only one NPB^- per complex. The 1:1 complexation constants for the solutes glycerol, fructose and sorbitol follow trends similar to complexation with B(OH)₄^- (aq.), i.e. the complexation constants increase with increasing number of -OH groups available for complexation. Assumption of 1:1 complex is not valid for 1, 2-propanediol, which showed overloading (more than one mole of solute complexed to one mole NPB^-) at higher concentrations. The -OH group on the NPB^- which is left uncomplexed after one solute molecule had bound to the other two -OH groups may be responsible for the overloading. Overloading is also observed in extraction of tactic acid, but through a different mechanism. It was found that TOMA⁺ can extract lactic acid to an extent comparable to the uptake of lactic acid by NPB^-. The complexation is probably through formation of an acid-base ion pair. Losses of NPBA into the aqueous phase could lead to problems, poor economics in industrial separation processes. One way of overcoming this problem would be to incorporate the NPBA onto a solid support.

Diffuse neutron scattering study of metallic interstitial solid solutions

International Nuclear Information System (INIS)

Barberis, P.

1991-10-01

We studied two interstitial solid solutions (Ni-C(1at%) and Nb-O(2at%) and two stabilized zirconia (ZrO2-CaO(13.6mol%) and ZrO2-Y2O3(9.6mol%) by elastic diffuse neutron scattering. We used polarized neutron scattering in the case of the ferromagnetic Ni-based sample, in order to determine the magnetic perturbation induced by the C atoms. Measurements were made on single crystals in the Laboratoire Leon Brillouin (CEA-CNRS, Saclay, France). An original algorithm to deconvolve time-of-flight spectra improved the separation between elastically and inelastically scattered intensities. In the case of metallic solutions, we used a simple non-linear model, assuming that interstitials are isolated and located in octahedral sites. Results are: - in both compounds, nearest neighbours are widely displaced away from the interstitial, while next nearest neighbours come slightly closer. - the large magnetic perturbation induced by carbon in Nickel decreases with increasing distance on the three first neighbour shells and is in good agreement with the total magnetization variation. - no chemical order between solute atoms could be evidenced. Stabilized zirconia exhibit a strong correlation between chemical order and the large displacements around vacancies and dopants. (Author). 132 refs., 38 figs., 13 tabs

Synthesis and structural characteristics of the spinel-type solid solutions in the Mn-V-Fe-O system

International Nuclear Information System (INIS)

Ponomaryov, V.I.; Dubrovina, I.N.; Zakharov, R.G.

1976-01-01

The part of the spinel region bounded by the compounds Mn 3 O 4 , Mn 2 VO 4 , Fe 2 VO 4 , and Fe 3 O 4 in the four-component system Mn-V-Fe-O was studied. The compounds were synthesized by ceramic technology. Samples were heated in a CO 2 atmosphere free of oxygen at 1100 0 C for 25-50 hr. It was found that the average composition of the spinel compound in the system had the formula Mnsub(1.00)Fesub(1.33)Vsub(0.67)O 4 . X-ray and neutron radiogrphic analyses were made. Crystallo-chemical formulas of the solid solutions considered are tabulated. The magnetic moments of saturation, calculated by the Neel model, are shown, and their experimental values are presented. The crystallo-chemical formulas of the spinel solid solutions in the Mn-V-Fe-O system are of interest in interpreting the concentration dependence of the physico-chemical properties of solid solutions of oxides based on metals with varying valence

Auger recombination in p-type InAs and in Gasub(x)Insub(1-x)As solid solutions

International Nuclear Information System (INIS)

Zotova, N.V.; Yassievich, I.N.

1977-01-01

The probability of the Auger recombination in p-type semiconductors, which is accompanied by transition of the second hole into the zone, splitted by spin-orbital interaction, was calculated. The above process is effective when the energy of spin-orbital splitting off Δ is close to the forbidden zone energy Esub(g), which takes place in the case of InAs, GaSb and solid solutions based on these compounds. The calculation is performed for the non-degenerate hole gas at a finite difference of Esub(g) - Δ. By means of the study of radiative recombination in InAs and Gasub(x)Insub(1-x)As solid solutions with small contents of GaAs (0 17 cm -3 . It is found that the quantum yield of radiative recombination increases sharply in Gasub(x)Insub(1-x)As solid solutions with the increase of x, which is associated with the increase of the difference of Esub(g) - Δ; the radiative recombination intensity increases in correspondence with the theoretical calculation made

Mesoporous yttria-zirconia and metal-yttria-zirconia solid solutions for fuel cells

Energy Technology Data Exchange (ETDEWEB)

Mamak, M.; Coombs, N.; Ozin, G. [Toronto Univ., ON (Canada). Dept. of Chemistry

2000-02-03

A new class of binary mesoporous yttria-zirconia (YZ) and ternary mesoporous metal-YZ materials (M = electroactive Ni/Pt) is presented here that displays the highest surface area of any known form of yttria-stabilized zirconia. These mesoporous materials form as solid solutions and retain their structural integrity to 800 C, which bodes well for their possible utilization in fuel cells. (orig.)

Laminating solution-processed silver nanowire mesh electrodes onto solid-state dye-sensitized solar cells

KAUST Repository

Hardin, Brian E.; Gaynor, Whitney; Ding, I-Kang; Rim, Seung-Bum; Peumans, Peter; McGehee, Michael D.

2011-01-01

Solution processed silver nanowire meshes (Ag NWs) were laminated on top of solid-state dye-sensitized solar cells (ss-DSCs) as a reflective counter electrode. Ag NWs were deposited in <1 min and were less reflective compared to evaporated Ag

Activity coefficients at infinite dilution of organic solutes in the ionic liquid 1-octyl-3-methylimidazolium hexafluorophosphate using gas-liquid chromatography at T = (313.15, 323.15, and 333.15) K

International Nuclear Information System (INIS)

Olivier, Eugene; Letcher, Trevor M.; Naidoo, Paramespri; Ramjugernath, Deresh

2010-01-01

Activity coefficients at infinite dilution were determined for 24 solutes: n-alkanes, alk-1-enes, alk-1-ynes, cycloalkanes, alkylbenzenes and alcohols in the ionic liquid 1-octyl-3-methylimidazolium hexafluorophosphate, [OMIM][PF 6 ], by gas-liquid chromatography at three different temperatures T = (313.15, 323.15, and 333.15) K. The partial molar excess enthalpy values at infinite dilution were calculated from the experimental data over the same temperature range. Capacities and selectivities at infinite dilution for the systems hexane/benzene and methanol/benzene were determined from the experimental data and compared to the literature values for other ionic liquids, as well as for industrial molecular solvents. The influence of the cation and anion of the ionic liquid on the activity coefficient is discussed, as well as the usefulness of [OMIM][PF 6 ] in separating organic liquids.

Localized solid-state amorphization at grain boundaries in a nanocrystalline Al solid solution subjected to surface mechanical attrition

Energy Technology Data Exchange (ETDEWEB)

Wu, X [State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100080 (China); Tao, N [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Hong, Y [State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100080 (China); Lu, J [LASMIS, University of Technology of Troyes, 10000, Troyes (France); Lu, K [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China)

2005-11-21

Using high-resolution electron microscopy, localized solid-state amorphization (SSA) was observed in a nanocrystalline (NC) Al solid solution (weight per cent 4.2 Cu, 0.3 Mn, the rest being Al) subjected to a surface mechanical attrition treatment. It was found that the deformation-induced SSA may occur at the grain boundary (GB) where either the high density dislocations or dislocation complexes are present. It is suggested that lattice instability due to elastic distortion within the dislocation core region plays a significant role in the initiation of the localized SSA at defective sites. Meanwhile, the GB of severely deformed NC grains exhibits a continuously varying atomic structure in such a way that while most of the GB is ordered but reveals corrugated configurations, localized amorphization may occur along the same GB.

Nitrate conversion and supercritical fluid extraction of UO2-CeO2 solid solution prepared by an electrolytic reduction-coprecipitation method

International Nuclear Information System (INIS)

Zhu, L.Y.; Duan, W.H.; Wen, M.F.; Xu, J.M.; Zhu, Y.J.

2014-01-01

A low-waste technology for the reprocessing of spent nuclear fuel (SNF) has been developed recently, which involves the conversion of actinide and lanthanide oxides with liquid N 2 O 4 into their nitrates followed by supercritical fluid extraction of the nitrates. The possibility of the reprocessing of SNF from high-temperature gas-cooled reactors (HTGRs) with nitrate conversion and supercritical fluid extraction is a current area of research in China. Here, a UO 2 -CeO 2 solid solution was prepared as a surrogate for a UO 2 -PuO 2 solid solution, and the recovery of U and Ce from the UO 2 -CeO 2 solid solution with liquid N 2 O 4 and supercritical CO 2 containing tri-n-butyl phosphate (TBP) was investigated. The UO 2 -CeO 2 solid solution prepared by electrolytic reduction-coprecipitation method had square plate microstructures. The solid solution after heat treatment was completely converted into nitrates with liquid N 2 O 4 . The XRD pattern of the nitrates was similar to that of UO 2 (NO 3 ) 2 . 3H 2 O. After 120 min of online extraction at 25 MPa and 50 , 99.98% of the U and 98.74% of the Ce were recovered from the nitrates with supercritical CO 2 containing TBP. The results suggest a promising potential technology for the reprocessing of SNF from HTGRs. (orig.)

A decontamination system for chemical weapons agents using a liquid solution on a solid sorbent

Energy Technology Data Exchange (ETDEWEB)

Waysbort, Daniel [Israel Institute for Biological Research, PO Box 19, Ness-Ziona 74100 (Israel); McGarvey, David J. [R and T Directorate, Edgewood Chemical and Biological Center (ECBC), Aberdeen Proving Ground-Edgewood Area, MD 21010 (United States)], E-mail: david.mcgarvey@us.army.mil; Creasy, William R.; Morrissey, Kevin M.; Hendrickson, David M. [SAIC, P.O. Box 68, Gunpowder Branch, Aberdeen Proving Ground, MD 21010 (United States); Durst, H. Dupont [R and T Directorate, Edgewood Chemical and Biological Center (ECBC), Aberdeen Proving Ground-Edgewood Area, MD 21010 (United States)

2009-01-30

A decontamination system for chemical warfare agents was developed and tested that combines a liquid decontamination reagent solution with solid sorbent particles. The components have fewer safety and environmental concerns than traditional chlorine bleach-based products or highly caustic solutions. The liquid solution, based on Decon Green{sup TM}, has hydrogen peroxide and a carbonate buffer as active ingredients. The best solid sorbents were found to be a copolymer of ethylene glycol dimethacrylate and n-lauryl methacrylate (Polytrap 6603 Adsorber); or an allyl methacrylate cross-linked polymer (Poly-Pore E200 Adsorber). These solids are human and environmentally friendly and are commonly used in cosmetics. The decontaminant system was tested for reactivity with pinacolyl methylphosphonofluoridate (Soman, GD), bis(2-chloroethyl)sulfide (Mustard, HD), and S-(2-diisopropylaminoethyl) O-ethyl methylphosphonothioate (VX) by using NMR Spectroscopy. Molybdate ion (MoO{sub 4}{sup -2}) was added to the decontaminant to catalyze the oxidation of HD. The molybdate ion provided a color change from pink to white when the oxidizing capacity of the system was exhausted. The decontaminant was effective for ratios of agent to decontaminant of up to 1:50 for VX (t{sub 1/2} {<=} 4 min), 1:10 for HD (t{sub 1/2} < 2 min with molybdate), and 1:10 for GD (t{sub 1/2} < 2 min). The vapor concentrations of GD above the dry sorbent and the sorbent with decontamination solution were measured to show that the sorbent decreased the vapor concentration of GD. The E200 sorbent had the additional advantage of absorbing aqueous decontamination solution without the addition of an organic co-solvent such as isopropanol, but the rate depended strongly on mixing for HD.

Defect structure of cubic solid solutions of alkaline earth and rare earth fluorides

NARCIS (Netherlands)

DenHartog, HW

1996-01-01

In this paper we will consider the disorder in some cubic solid solutions consisting of one of the alkaline earth fluorides and one of the rare earth fluorides. This is an attractive group of model materials, because these materials have a rather simple overall cubic structure. We will discuss the

Phase transitions in solid Kr-CH4 solutions and rotational excitations in phase II

International Nuclear Information System (INIS)

Bagatskii, M.I.; Mashchenko, D.A.; Dudkin, V.V.

2007-01-01

The heat capacity C p of solid Kr-n CH 4 solutions with the CH 4 concentrations n=0.82, 0.86, 0.90 as well as solutions with n=0.90, 0.95 doped with 0.002 O 2 impurity has been investigated under equilibrium vapor pressure over the internal 1-24 K. The (T,n)-phase diagram was refined and the region of two-phase states was determined for Kr-n CH 4 solid solutions. The contribution of the rotational subsystem, C r ot, to the heat capacity of the solutions has been separated. Analysis of C r ot(T) at T 1 and E 2 between the tunnel levels of the A-, T- and A-, E--nuclear-spin species of CH 4 molecules in the orientationally ordered subsystem, and to determine the effective energy gaps E 1 between lowest levels of the A- and T- species. The relations τ(n) and E 1 (n) stem from changes of the effective potential field caused as the replacement of CH 4 molecules by Kr atoms at sites of the ordered sublattices. The effective gaps E L between a group of tunnel levels of the ground-state liberation state and the nearest group of excited levels of the liberation state of the ordered CH 4 molecules in the solutions with n=0.90 (E L =52 K) and 0.95 (E L =55 K) has been estimated

A solid solution series of atacamite type Ni{sub 2x}Mg{sub 2−2x}Cl(OH){sub 3}

Energy Technology Data Exchange (ETDEWEB)

Bette, Sebastian [TU Bergakademie Freiberg, Institute of Inorganic Chemistry, Leipziger Strasse 29, Freiberg 09596 (Germany); Dinnebier, Robert E. [Max Planck Institute for Solid State Research, Heisenbergstrasse 1, Stuttgart 70569 (Germany); Röder, Christian [TU Bergakademie Freiberg, Institute of Theoretical Physics, Leipziger Strasse 23, Freiberg 09596 (Germany); Freyer, Daniela, E-mail: daniela.freyer@chemie.tu-freiberg.de [TU Bergakademie Freiberg, Institute of Inorganic Chemistry, Leipziger Strasse 29, Freiberg 09596 (Germany)

2015-08-15

For the first time a complete solid solution series Ni{sub 2x}Mg{sub 2−2x}Cl(OH){sub 3} of an atacamite type alkaline main group metal chloride, Mg{sub 2}Cl(OH){sub 3}, and a transition group metal chloride, Ni{sub 2}Cl(OH){sub 3}, was prepared and characterized by chemical and thermal analysis as well as by Raman and IR spectroscopy, and high resolution laboratory X-ray powder diffraction. All members of the solid solution series crystallize in space group Pnam (62). The main building units of these crystal structures are distorted, edge-linked Ni/MgO{sub 4}Cl{sub 2} and Ni/MgO{sub 5}Cl octahedra. The distribution of Ni{sup 2+}- and Mg{sup 2+}-ions among these two metal-sites within the solid solution series is discussed in detail. The crystallization of the solid solution phases occurs via an intermediate solid solution series, (Ni/Mg)Cl{sub 2x}(OH){sub 2−2x}, with variable Cl: OH ratio up to the 1:3 ratio according to the formula Ni{sub 2x}Mg{sub 2−2x} Cl(OH){sub 3}. For one isolated intermediate solid solution member, Ni{sub 0.70}Mg{sub 0.30}Cl{sub 0.58}(OH){sub 1.42}, the formation and crystal structure is presented as well. - Graphical abstract: For the first time a complete solid solution series, Ni{sub 2x}Mg{sub 2−2x} Cl(OH){sub 3}, was synthesized and characterized. Structure solution by revealed that Ni{sup 2+} prefers to occupy the Jahn–Teller-like distorted hole, out of two available cation sites. Substitution of Ni{sup 2+} by Mg{sup 2+} in atacamite type Ni{sub 2}Cl(OH){sub 3} results in systematic band shifts in Raman and IR spectra as well as in systematic changes in thermal properties. The α-polymorphs M{sub 2}Cl(OH){sub 3} with M=Mg{sup 2+}, Ni{sup 2+} and other divalent transition metal ions, as described in literature, were identified as separate compounds. - Highlights: • First synthesis of solid solution series between main and transition metal chloride. • Ni{sup 2+} prefers to occupy Jahn–Teller-like distorted octahedral holes

Magnetoelectric effect in (BiFeO3x–(BaTiO31-x solid solutions

Directory of Open Access Journals (Sweden)

Kowal Karol

2015-03-01

Full Text Available The aim of the present work was to study magnetoelectric effect (ME in (BiFeO3x-(BaTiO31-x solid solutions in terms of technological conditions applied in the samples fabrication process. The rapidly growing interest in these materials is caused by their multiferroic behaviour, i.e. coexistence of both electric and magnetic ordering. It creates possibility for many innovative applications, e.g. in steering the magnetic memory by electric field and vice versa. The investigated samples of various chemical compositions (i.e. x = 0.7, 0.8 and 0.9 were prepared by the solid-state sintering method under three sets of technological conditions differing in the applied temperature and soaking time. Measurements of the magnetoelectric voltage coefficient αME were performed using a dynamic lock-in technique. The highest value of αME was observed for 0.7BiFeO3-0.3BaTiO3 solid solution sintered at the highest temperature (T = 1153 K after initial electrical poling despite that the soaking time was reduced 10 times in this case.

Structure and dynamics of solvated Ba(II) in dilute aqueous solution - an ab initio QM/MM MD approach

International Nuclear Information System (INIS)

Hofer, Thomas S.; Rode, Bernd M.; Randolf, Bernhard R.

2005-01-01

Structural properties of the hydrated Ba(II) ion have been investigated by ab initio quantum mechanical/molecular mechanical (QM/MM) molecular dynamics (MD) simulations at double zeta HF quantum mechanical level. The first shell coordination number was found to be 9.3, and several other structural parameters such as angular distribution functions, radial distribution functions and tilt- and θ-angle distributions allowed the full characterization of the hydration structure of the Ba(II) ion in dilute aqueous solution. Velocity autocorrelation functions were used to calculate librational and vibrational motions, ion-ligand motions as well as reorientation times. Different dynamical parameters such as water reorientation, mean ligand residence time, the number of ligand exchange processes and rate constants were also analyzed and the ligand exchange rate constant for the first shell was determined as k = 5.3 x 10 10 s -1

Chemically and compositionally modified solid solution disordered multiphase nickel hydroxide positive electrode for alkaline rechargeable electrochemical cells

Science.gov (United States)

Ovshinsky, Stanford R.; Corrigan, Dennis; Venkatesan, Srini; Young, Rosa; Fierro, Christian; Fetcenko, Michael A.

1994-01-01

A high capacity, long cycle life positive electrode for use in an alkaline rechargeable electrochemical cell comprising: a solid solution nickel hydroxide material having a multiphase structure that comprises at least one polycrystalline .gamma.-phase including a polycrystalline .gamma.-phase unit cell comprising spacedly disposed plates with at least one chemical modifier incorporated around the plates, the plates having a range of stable intersheet distances corresponding to a 2.sup.+ oxidation state and a 3.5.sup.+, or greater, oxidation state; and at least one compositional modifier incorporated into the solid solution nickel hydroxide material to promote the multiphase structure.

Specific features of kinetics of He/sup 3/-He/sup 4/ solid solution transformations at superlow temperatures

Energy Technology Data Exchange (ETDEWEB)

Mikheev, V A; Majdanov, V A; Mikhin, N P

1986-06-01

The NMR data on the phase transition kinetics of /sup 3/He-/sup 4/He solid solutions at T=100 mK are considered. Studied are solid helium samples of a molecular volume of 20.55 cm/sup 2//mol with a /sup 3/He content of 0.54%. An unusually long phase transition time is found which is dependent on the prehistory of sample. The spin diffusion of /sup 3/He in the transformated solution concentrated phase is found to be of a quasi-one-dimensional nature with the diffusion coefficient value typical of liquid.

Phenomenology of polymer solution dynamics

National Research Council Canada - National Science Library

Phillies, George D. J

2011-01-01

... solutions, not dilute solutions or polymer melts. From centrifugation and solvent dynamics to viscosity and diffusion, experimental measurements and their quantitative representations are the core of the discussion...

High-Reynolds-number turbulent-boundary-layer wall-pressure fluctuations with dilute polymer solutions

Science.gov (United States)

Elbing, Brian R.; Winkel, Eric S.; Ceccio, Steven L.; Perlin, Marc; Dowling, David R.

2010-08-01

Wall-pressure fluctuations were investigated within a high-Reynolds-number turbulent boundary layer (TBL) modified by the addition of dilute friction-drag-reducing polymer solutions. The experiment was conducted at the U.S. Navy's Large Cavitation Channel on a 12.9 m long flat-plate test model with the surface hydraulically smooth (k+<0.2) and achieving downstream-distance-based Reynolds numbers to 220×106. The polymer (polyethylene oxide) solution was injected into the TBL through a slot in the surface. The primary flow diagnostics were skin-friction drag balances and an array of flush-mounted dynamic pressure transducers 9.8 m from the model leading edge. Parameters varied included the free-stream speed (6.7, 13.4, and 20.2 m s-1) and the injection condition (polymer molecular weight, injection concentration, and volumetric injection flux). The behavior of the pressure spectra, convection velocity, and coherence, regardless of the injection condition, were determined primarily based on the level of drag reduction. Results were divided into two regimes dependent on the level of polymer drag reduction (PDR), nominally separated at a PDR of 40%. The low-PDR regime is characterized by decreasing mean-square pressure fluctuations and increasing convection velocity with increasing drag reduction. This shows that the decrease in the pressure spectra with increasing drag reduction is due in part to the moving of the turbulent structures from the wall. Conversely, with further increases in drag reduction, the high-PDR regime has negligible variation in the mean-squared pressure fluctuations and convection velocity. The convection velocity remains constant at approximately 10% above the baseline-flow convection velocity, which suggests that the turbulent structures no longer move farther from the wall with increasing drag reduction. In light of recent numerical work, the coherence results indicate that in the low-PDR regime, the turbulent structures are being elongated in

Simultaneous solution algorithms for Eulerian-Eulerian gas-solid flow models: Stability analysis and convergence behaviour of a point and a plane solver

International Nuclear Information System (INIS)

Wilde, Juray de; Vierendeels, Jan; Heynderickx, Geraldine J.; Marin, Guy B.

2005-01-01

Simultaneous solution algorithms for Eulerian-Eulerian gas-solid flow models are presented and their stability analyzed. The integration algorithms are based on dual-time stepping with fourth-order Runge-Kutta in pseudo-time. The domain is solved point or plane wise. The discretization of the inviscid terms is based on a low-Mach limit of the multi-phase preconditioned advection upstream splitting method (MP-AUSMP). The numerical stability of the simultaneous solution algorithms is analyzed in 2D with the Fourier method. Stability results are compared with the convergence behaviour of 3D riser simulations. The impact of the grid aspect ratio, preconditioning, artificial dissipation, and the treatment of the source terms is investigated. A particular advantage of the simultaneous solution algorithms is that they allow a fully implicit treatment of the source terms which are of crucial importance for the Eulerian-Eulerian gas-solid flow models and their solution. The numerical stability of the optimal simultaneous solution algorithm is analyzed for different solids volume fractions and gas-solid slip velocities. Furthermore, the effect of the grid resolution on the convergence behaviour and the simulation results is investigated. Finally, simulations of the bottom zone of a pilot-scale riser with a side solids inlet are experimentally validated

Purification of uranothorite solid solutions from polyphase systems

Energy Technology Data Exchange (ETDEWEB)

Clavier, Nicolas, E-mail: nicolas.clavier@icsm.fr [ICSM, UMR 5257 CEA/CNRS/UM2/ENSCM, Site de Marcoule – Bât. 426, BP 17171, 30207 Bagnols/Cèze cedex (France); Szenknect, Stéphanie; Costin, Dan Tiberiu; Mesbah, Adel; Ravaux, Johann [ICSM, UMR 5257 CEA/CNRS/UM2/ENSCM, Site de Marcoule – Bât. 426, BP 17171, 30207 Bagnols/Cèze cedex (France); Poinssot, Christophe [CEA/DEN/DRCP/DIR, Site de Marcoule – Bât. 400, BP 17171, 30207 Bagnols/Cèze cedex (France); Dacheux, Nicolas [ICSM, UMR 5257 CEA/CNRS/UM2/ENSCM, Site de Marcoule – Bât. 426, BP 17171, 30207 Bagnols/Cèze cedex (France)

2013-10-15

Graphical abstract: Display Omitted -- Highlights: •Purification of Th{sub 1−x}U{sub x}SiO{sub 4} uranothorites from oxide mixture was investigated. •Repetition of centrifugation steps was discarded due to poor recovery yields. •Successive washings in acid and basic media allowed the elimination of oxide secondary phases. •Structural and microstructural characterization of the purified samples was provided. -- Abstract: The mineral coffinite, nominally USiO{sub 4}, and associated Th{sub 1−x}U{sub x}SiO{sub 4} uranothorite solid solutions are of great interest from a geochemical point of view and in the case of the direct storage of spent nuclear fuels. Nevertheless, they clearly exhibit a lack in the evaluation of their thermodynamic data, mainly because of the difficulties linked with their preparation as pure phases. This paper thus presents physical and chemical methods aiming to separate uranothorite solid solutions from oxide additional phases such as amorphous SiO{sub 2} and nanometric crystallized Th{sub 1−y}U{sub y}O{sub 2}. The repetition of centrifugation steps envisaged in first place was rapidly dropped due to poor recovery yields, to the benefit of successive washings in acid then basic media. Under both static and dynamic flow rates (i.e. low or high rate of leachate renewal), ICP-AES (Inductively Coupled Plasma – Atomic Emission Spectroscopy) analyses revealed the systematic elimination of Th{sub 1−y}U{sub y}O{sub 2} in acid media and of SiO{sub 2} in basic media. Nevertheless, two successive steps were always needed to reach pure samples. On this basis, a first cycle performed in static conditions was chosen to eliminate the major part of the accessory phases while a second one, in dynamic conditions, allowed the elimination of the residual impurities. The complete purification of the samples was finally evidenced through the characterization of the samples by the means of PXRD (Powder X-Ray Diffraction), SEM (Scanning Electron

Investigation of a 0.52 eV absorption band of n-type Ge1-xSix solid solutions irradiated with fast electrons at 77 K

International Nuclear Information System (INIS)

Abbasov, Sh.M.; Allakhverdiev, K.R.; Agaverdieva, G.T.; Bakhyshov, N.A.; Nagiev, A.I.

1987-01-01

Solid solutions belonging to the Ge 1-x Si x system are among the promising semiconductor materials. There is no published information on the absorption band in the region of 0.52 eV in Ge 1-x Si x solid solutions irradiated with fast electrons. The authors determined the infrared absorption spectra, impurity photoconductivity, and Hall effect of n-type Ge 1-x Si x solid solutions doped with antimony. These solid solutions were irradiated at 77 K with 5 MeV electrons in doses up to 2 x 10 17 cm -2 . This irradiation was carried out by a method described in Ref. 3

A New Class of Ternary Compound for Lithium-Ion Battery: from Composite to Solid Solution.

Science.gov (United States)

Wang, Jiali; Wu, Hailong; Cui, Yanhua; Liu, Shengzhou; Tian, Xiaoqing; Cui, Yixiu; Liu, Xiaojiang; Yang, Yin

2018-02-14

Searching for high-performance cathode materials is a crucial task to develop advanced lithium-ion batteries (LIBs) with high-energy densities for electrical vehicles (EVs). As a promising lithium-rich material, Li 2 MnO 3 delivers high capacity over 200 mAh g -1 but suffers from poor structural stability and electronic conductivity. Replacing Mn 4+ ions by relatively larger Sn 4+ ions is regarded as a possible strategy to improve structural stability and thus cycling performance of Li 2 MnO 3 material. However, large difference in ionic radii of Mn 4+ and Sn 4+ ions leads to phase separation of Li 2 MnO 3 and Li 2 SnO 3 during high-temperature synthesis. To prepare solid-solution phase of Li 2 MnO 3 -Li 2 SnO 3 , a buffer agent of Ru 4+ , whose ionic radius is in between that of Mn 4+ and Sn 4+ ions, is introduced to assist the formation of a single solid-solution phase. The results show that the Li 2 RuO 3 -Li 2 MnO 3 -Li 2 SnO 3 ternary system evolves from mixed composite phases into a single solid-solution phase with increasing Ru content. Meanwhile, discharge capacity of this ternary system shows significantly increase at the transformation point which is ascribed to the improvement of Li + /e - transportation kinetics and anionic redox chemistry for solid-solution phase. The role of Mn/Sn molar ratio of Li 2 RuO 3 -Li 2 MnO 3 -Li 2 SnO 3 ternary system has also been studied. It is revealed that higher Sn content benefits cycling stability of the system because Sn 4+ ions with larger sizes could partially block the migration of Mn 4+ and Ru 4+ from transition metal layer to Li layer, thus suppressing structural transformation of the system from layered-to-spinel phase. These findings may enable a new route for exploring ternary or even quaternary lithium-rich cathode materials for LIBs.

Properties of magnetically diluted nanocrystals prepared by mechanochemical route

International Nuclear Information System (INIS)

Balaz, P.; Skorvanek, I.; Fabian, M.; Kovac, J.; Steinbach, F.; Feldhoff, A.; Sepelak, V.; Jiang, J.; Satka, A.; Kovac, J.

2010-01-01

The bulk and surface properties of magnetically diluted Cd 0.6 Mn 0.4 S nanocrystals synthesized by solid state route in a planetary mill were studied. XRD, SEM, TEM (HRTEM), low-temperature N 2 sorption, nanoparticle size distribution as well as SQUID magnetometry methods have been applied. The measurements identified the aggregates of small nanocrystals, 5-10 nm in size. The homogeneity of produced particles with well developed specific surface area (15-66 m 2 g -1 ) was documented. The transition from the paramagnetic to the spin-glass-like phase has been observed below ∼40 K. The changes in the magnetic behaviour at low temperatures seem to be correlated with the formation of the new surface area as a consequence of milling. The magnetically diluted Cd 0.6 Mn 0.4 S nanocrystals are obtained in the simple synthesis step, making the process attractive for industrial applications.

Simple thermodynamic model of the extension of solid solution of Cu-Mo alloys processed by mechanical alloying

International Nuclear Information System (INIS)

Aguilar, C.; Guzman, D.; Rojas, P.A.; Ordonez, Stella; Rios, R.

2011-01-01

Highlights: → Extension of solid solution in Cu-Mo systems achieved by mechanical alloying. → Simple thermodynamic model to explain extension of solid solution of Mo in Cu. → Model gives results that are consistent with the solubility limit extension reported in other works. - Abstract: The objective of this work is proposing a simple thermodynamic model to explain the increase in the solubility limit of the powders of the Cu-Mo systems or other binary systems processed by mechanical alloying. In the regular solution model, the effects of crystalline defects, such as; dislocations and grain boundary produced during milling were introduced. The model gives results that are consistent with the solubility limit extension reported in other works for the Cu-Cr, Cu-Nb and Cu-Fe systems processed by mechanical alloying.

Solid solution inhomogeneity in DC-cast AlMn(Fe,Si) ingots

International Nuclear Information System (INIS)

Lakner, J.; Kovacs-Csetenyi, E.; Lal, K.

1990-01-01

The aim of this work was to characterize the structure in cast state of the AlMn1 alloy containing different Fe and Si concentration. The casting parameters were intended to keep constant and the effect of impurities was studied. The inhomogeneity along the diameter of cast billet was characterized by the dendrite arm spacing and by the solid solution content. To explain the results the model developed for binary AlFe and AlMn alloys was applied

The effects of heating and dilution on the rheological and physical properties of Tank 241-SY-101 waste

International Nuclear Information System (INIS)

Tingey, J.M.; Bredt, P.R.; Shade, E.H.

1994-10-01

Of the 177 high-level waste underground storage tanks at the Hanford Site, 25 have been identified as being potentially capable of generating and releasing flammable gas. Tank 241-SY-101 has exhibited periodic releases of gas, and in some cases the gas released has exceeded the lower flammable gas limit. The components of the released gas from Tank 241-SY-101 are hydrogen, nitrous oxide, nitrogen, ammonia, carbon monoxide, and methane. A mitigation strategy that may effectively reduce the retention and release of these gases and the release of flammable gases is dilution coupled with eating of the tank wastes. The purpose of this work was to determine changes in rheological and physical properties caused by heating and dilution of actual 241-SY-101 waste. In May and December 1991, following periodic gas releases, samples of the waste in Tank 241-SY-101 were obtained. Current work quantified the effects of heating coupled with NaOH dilution of a combination of waste samples from Tank 241-SY-101 characteristic of a non-convective layer. The experimental approach and results of this heating and dilution study on Tank 241-SY-101 waste samples are described in Sections 2 and 3, respectively. In Section 3.1, a discussion of the rheological properties of the waste as a function of shearing forces, volume percent dilution, and temperature is presented. In Section 3.2, the physical properties of the waste dilutions are described, including the densities of the slurry, filtered solids, and filtrate; the settling behavior; and the percent filtered solids in the composite sample and each of the composite dilutions. A brief discussion of the results and uncertainties is given is Section 3.3. The conclusions of this investigation are reported in Section 4

A model for the viscosity of dilute smectite gels

International Nuclear Information System (INIS)

Liu, L.

2011-01-01

A simple yet accurate model describing the viscosity of dilute suspensions of sodium montmorillonite in dilute homo-ionic solutions is presented. Taking the clay particle and the surrounding clouds of ions as a whole as an uncharged but soft, coin-like particle, the Huggins' equation for a suspension of uncharged particles is extended in the model to account for not only the primary and the secondary electro-viscous effects, but also the multi-particle interaction. The agreements between the predicted and measured results are excellent. The Huggins' coefficient obtained compares favorably with available data, while the intrinsic viscosity reduces to the Simha's equation in the large limit of ionic strength, suggesting that the model is robust. (authors)

Cadmium determination in natural waters at the limit imposed by European legislation by isotope dilution and TiO{sub 2} solid-phase extraction

Energy Technology Data Exchange (ETDEWEB)

Garcia-Ruiz, Silvia; Quetel, Christophe R. [Institute for Reference Materials and Measurements, Joint Research Centre - European Commission, Geel (Belgium); Petrov, Ivan [Institute for Reference Materials and Measurements, Joint Research Centre - European Commission, Geel (Belgium); Universite Libre de Bruxelles, Department of Earth and Environmental Sciences, Brussels (Belgium); Vassileva, Emilia [Institute for Reference Materials and Measurements, Joint Research Centre - European Commission, Geel (Belgium); IAEA-Marine Environment Laboratories, Monaco (Monaco)

2011-11-15

The cadmium content in surface water is regulated by the last European Water Framework Directive to a maximum between 0.08 and 0.25 {mu}g L{sup -1} depending on the water type and hardness. Direct measurement of cadmium at this low level is not straightforward in real samples, and we hereby propose a validated method capable of addressing cadmium content below {mu}g L{sup -1} level in natural water. It is based on solid-phase extraction using TiO{sub 2} nanoparticles as solid sorbent (0.05 g packed in mini-columns) to allow the separation and preconcentration of cadmium from the sample, combined to direct isotope dilution and detection by inductively coupled plasma mass spectrometry (ID-ICP-MS). The extraction setup is miniaturised and semi-automated to reduce risks of sample contamination and improve reproducibility. Procedural blanks for the whole measurement process were 5.3 {+-} 2.8 ng kg{sup -1} (1 s) for 50 g of ultrapure water preconcentrated ten times. Experimental conditions influencing the separation (including loading pH, sample flow rates, and acid concentration in the eluent) were evaluated. With isotope dilution the Cd recovery rate does not have to be evaluated carefully. Moreover, the mathematical model associated to IDMS is known, and provides transparency for the uncertainty propagation. Our validation protocol was in agreement with guidelines of the ISO/IEC 17025 standard (chapter 5.4.5). Firstly, we assessed the experimental factors influencing the final result. Secondly, we compared the isotope ratios measured after our separation procedure to the reference values obtained with a different protocol for the digested test material IMEP-111 (mineral feed). Thirdly, we analysed the certified reference material BCR-609 (groundwater). Finally, combined uncertainties associated to our results were estimated according to ISO-GUM guidelines (typically, 3-4% k = 2 for a cadmium content of around 100 ng kg{sup -1}). We applied the developed method to the

Relative frequency of formation of base radioproduct, single and double strand breaks on irradiation of diluted aqueous solution of DNA

International Nuclear Information System (INIS)

Ryznar, L.; Drasil, V.

1975-01-01

Diluted aqueous solution of DNA labelled with 6- 3 H-TdR was irradiated in the absence of oxygen and numbers of formed single and double strand breaks and the 5,6-dihydrothymine (DHT) yield were determined. The results indicate that, under given conditions, a molecule of a base radioproduct is formed approximately 10 times more frequently than one single strand break. The occurence of a single strand break is 20 times higher than that of a double strand break. The DNA labelled with 6- 3 H-TdR was isolated from mice fibroblasts of L-strain according to Marmur (specific activity 3.0 MBq/82 μCi/mg DNA, molecular weight M/sub n/=9.32x10 6 dalton). Solution of DNA was irradiated in the absence of oxygen (180 Gy /1.8x10 4 rads/, absorbed dose rate 0.3 Gy/s). It was lyophilized with an addition of non-labelled thymine, thymidine and DHT and then hydrolysed with 90% formic acid. The dried hydrolysate was chromatographed with irradiated non-labelled thymine added as a carrier. (F.G.)

Neutron diffraction radiation of solid solution of carbon and hydrogen in the α-titanium in the homogeneity domain

International Nuclear Information System (INIS)

Mirzaev, B.B.; Khidirov, I.; Mukhtarova, N.N.

2005-01-01

In the work by the neutron-graph the homogeneity domain of the introduction solid solution TiC x H y is determined. The sample neutron grams have been taken on the neutron diffractometer (λ=.1085 nm) installed at the thermal column of the WWR-SM reactor (INF AN RUz). For the phase analysis and estimation of solid solutions homogeneity the X-ray graph was used. X-ray grams were taken on the X-ray diffractometer DRON-3M with use of CuK α radiation (λ=0.015418 nm)

Study of the sintering process and the formation of a (Th, U) O2 solid solution

International Nuclear Information System (INIS)

Tomasi, Roberto

1979-01-01

The effect of some variables in the (Th, U) O 2 sintering process and solid solution formation was studied. ThO 2 , U 3 O 8 and UO 2 powder were prepared. The ThO 2 powders were obtained by calcination of thorium at 500 and 750 deg C; the U 3 O 8 powders were derived from the calcination of ADU at 660 and 750 deg C; the UO 2 powder were prepared from ADU and from ATCU. The different characteristics of these materials were determined by measurements of surface area, by scanning electron microscopy, tap density tests, X-ray diffractometry and by measurements of the O/U ratios. The oxide mixtures were chosen in order to produce a final composition with 10 w/o of UO 2 . A mixture of thorium oxalate and ADU was also prepared by calcining these salts in air at 700 deg C, in order to obtain certain amount of solid solution prior to sintering. The sintering operations were developed in an argon atmosphere at temperatures between 1400 and 1700 deg C, during interval varying from 1 to 4 hours. The effect of the mixture characteristics on the sintering process and solid solution formation were studied considering the results of densification, microstructure development and X-ray diffractometry. The ThO 2 powder characteristics have a main effect on the mixtures compactability and sinterability, the higher calcining temperatures increasing the green density, but decreasing the final density of the sintered pellets. In the sintering of mixtures containing U 3 O 3 , this oxide is reduced to UO 2 and it is possible to obtain pellets with density and microstructures similar to those produced from mixtures containing UO 2 . But if oxygen in excess is present during sintering, the process is affected, occurring exaggerated grain growth. The densification results were related to the Coble's kinetics equation for second stage of sintering, valid for bulk diffusion, grain boundary acting as vacancy sinks. The sintering activation energy is independent from the powder starting

Computational modeling of chemical reactions and interstitial growth and remodeling involving charged solutes and solid-bound molecules.

Science.gov (United States)

Ateshian, Gerard A; Nims, Robert J; Maas, Steve; Weiss, Jeffrey A

2014-10-01

Mechanobiological processes are rooted in mechanics and chemistry, and such processes may be modeled in a framework that couples their governing equations starting from fundamental principles. In many biological applications, the reactants and products of chemical reactions may be electrically charged, and these charge effects may produce driving forces and constraints that significantly influence outcomes. In this study, a novel formulation and computational implementation are presented for modeling chemical reactions in biological tissues that involve charged solutes and solid-bound molecules within a deformable porous hydrated solid matrix, coupling mechanics with chemistry while accounting for electric charges. The deposition or removal of solid-bound molecules contributes to the growth and remodeling of the solid matrix; in particular, volumetric growth may be driven by Donnan osmotic swelling, resulting from charged molecular species fixed to the solid matrix. This formulation incorporates the state of strain as a state variable in the production rate of chemical reactions, explicitly tying chemistry with mechanics for the purpose of modeling mechanobiology. To achieve these objectives, this treatment identifies the specific theoretical and computational challenges faced in modeling complex systems of interacting neutral and charged constituents while accommodating any number of simultaneous reactions where reactants and products may be modeled explicitly or implicitly. Several finite element verification problems are shown to agree with closed-form analytical solutions. An illustrative tissue engineering analysis demonstrates tissue growth and swelling resulting from the deposition of chondroitin sulfate, a charged solid-bound molecular species. This implementation is released in the open-source program FEBio ( www.febio.org ). The availability of this framework may be particularly beneficial to optimizing tissue engineering culture systems by examining the

Synthesis and properties of γ-Ga2O3-Al2O3 solid solutions

Science.gov (United States)

Afonasenko, T. N.; Leont'eva, N. N.; Talzi, V. P.; Smirnova, N. S.; Savel'eva, G. G.; Shilova, A. V.; Tsyrul'nikov, P. G.

2017-10-01

The textural and structural properties of mixed oxides Ga2O3-Al2O3, obtained via impregnating γ-Al2O3 with a solution of Ga(NO3)3 and subsequent heat treatment, are studied. According to the results from X-ray powder diffraction, gallium ions are incorporated into the structure of aluminum oxide to form a solid solution of spinel-type γ-Ga2O3-Al2O3 up to a Ga2O3 content of 50 wt % of the total weight of the sample, accompanied by a reduction in the specific surface area, volume, and average pore diameter. It is concluded that when the Ga2O3 content exceeds 50 wt %, the β-Ga2O3 phase is observed along with γ-Ga2O3-Al2O3 solid solution. 71Ga and 27Al NMR spectroscopy shows that gallium replaces aluminum atoms from the tetrahedral position to the octahedral coordination in the structure of γ-Ga2O3-Al2O3.

Microstructural and microchemical studies of phase stability in V-O solid solution

Energy Technology Data Exchange (ETDEWEB)

Ghosh, Chanchal, E-mail: chanchal@igcar.gov.in [Metallurgy & Materials Group, Indira Gandhi Centre for Atomic Research, HBNI, Kalpakkam 603102, Tamil Nadu (India); Singh, Akash [Metallurgy & Materials Group, Indira Gandhi Centre for Atomic Research, HBNI, Kalpakkam 603102, Tamil Nadu (India); Basu, Joysurya [Metallurgy & Materials Group, Indira Gandhi Centre for Atomic Research, HBNI, Kalpakkam 603102, Tamil Nadu (India); Department of Metallurgical Engineering, Indian Institute of Technology (BHU), Varanasi 221005, Uttar Pradesh (India); Ramachandran, Divakar; Mohandas, E [Metallurgy & Materials Group, Indira Gandhi Centre for Atomic Research, HBNI, Kalpakkam 603102, Tamil Nadu (India)

2017-02-15

Over the last couple of decades vanadium and V-based alloys have received significant attention as a potential structural material for fusion power applications because of their favourable mechanical properties under irradiation and at elevated temperatures. They are also considered as the advanced options of storage materials for hydrogen and its isotopes. However, the higher affinity of V for O, C and N poses critical challenges in its engineering applications since they lead to degradation of mechanical properties. They can further interact with the matrix to produce metallic oxy-carbo-nitride precipitates. To a certain limit, these precipitates are beneficial and can be exploited to enhance the mechanical behaviour of the alloy through suitable microstructural design. However, this requires a prior knowledge of the interaction between the alloy and the impurity solutes. In the present work vanadium specific experiments have been designed and carried out to bring out the V-interstitial solute interaction by charging oxygen in the near surface region of vanadium. Microstructural and microchemical behaviour of the V-O solid solution has been studied through HRTEM (high resolution transmission electron microscopy) and HAADF (high angle annular dark field) coupled with EELS. Quantitative electron microscopy has been carried out to study structural modification of the alloy in atomic level caused by O charging. - Highlights: •Controlled experiments were carried out in pulsed laser ablation set-up to promote V-O interaction. • As a consequence of O dissolution, V transformed into a bct structure which is otherwise a bcc structure. •In V-O solid solution, dissolved O in the V matrix introduces significant amount of lattice strain. • Present work can be extended for introducing interstitial O in other pure transition metals and their alloys.

Direct measurements of the enthalpy of solution of solid solute in supercritical fluids: study on the CO2-naphthalene system.

Science.gov (United States)

Zhang, X; Han, B; Zhang, J; Li, H; He, J; Yan, H

2001-10-01

A setup for a calorimeter for simultaneously measuring the solubility and the solution enthalpy of solid solutes in supercritical fluids (SCFs) has been established. The enthalpy of solution of naphthalene in supercritical CO2 was measured at 308.15 K in the pressure range from 8.0-11.0 MPa. It was found that the enthalpy of solution (deltaH) was negative in the pressure range from 8.0 to 9.5 MPa, and the absolute value decreased with increasing pressure. In this pressure range, the dissolution of the solute was enthalpy driven. However, the deltaH became positive at pressures higher than 9.5 MPa, and the dissolution was entropy driven. Monte Carlo simulation was performed to analyze the local structural environment of the solvated naphthalene molecules in supercritical CO2 under the experimental conditions for the calorimetric measurements. By combining the enthalpy data and the simulation results, it can be deduced that the energy level of CO2 in the high compressible region is higher than that at higher pressures, which results in the large negative enthalpy of solution and the larger degree of solvent-solute clustering in the high compressible region.

High temperature dilute phosphoric acid pretreatment of corn stover for furfural and ethanol production

Science.gov (United States)

Furfural was produced from corn stover by one stage pretreatment process using dilute H3PO4 and solid residues following furfural production were used for ethanol production by Saccharomyces cerevisiae NRRL- Y2034. A series of experiments were conducted at varied temperatures (140-200 oC) and acid ...