Reactive transport in a partially molten system with binary solid solution
Jordan, J.; Hesse, M. A.
2017-12-01
Melt extraction from the Earth's mantle through high-porosity channels is required to explain the composition of the oceanic crust. Feedbacks from reactive melt transport are thought to localize melt into a network of high-porosity channels. Recent studies invoke lithological heterogeneities in the Earth's mantle to seed the localization of partial melts. Therefore, it is necessary to understand the reaction fronts that form as melt flows across the lithological interface of a heterogeneity and the background mantle. Simplified melting models of such systems aide in the interpretation and formulation of larger scale mantle models. Motivated by the aforementioned facts, we present a chromatographic analysis of reactive melt transport across lithological boundaries, using theory for hyperbolic conservation laws. This is an extension of well-known linear trace element chromatography to the coupling of major elements and energy transport. Our analysis allows the prediction of the feedbacks that arise in reactive melt transport due to melting, freezing, dissolution and precipitation for frontal reactions. This study considers the simplified case of a rigid, partially molten porous medium with binary solid solution. As melt traverses a lithological contact-modeled as a Riemann problem-a rich set of features arise, including a reacted zone between an advancing reaction front and partial chemical preservation of the initial contact. Reactive instabilities observed in this study originate at the lithological interface rather than along a chemical gradient as in most studies of mantle dynamics. We present a regime diagram that predicts where reaction fronts become unstable, thereby allowing melt localization into high-porosity channels through reactive instabilities. After constructing the regime diagram, we test the one-dimensional hyperbolic theory against two-dimensional numerical experiments. The one-dimensional hyperbolic theory is sufficient for predicting the
PARALLEL SOLUTION METHODS OF PARTIAL DIFFERENTIAL EQUATIONS
Directory of Open Access Journals (Sweden)
Korhan KARABULUT
1998-03-01
Full Text Available Partial differential equations arise in almost all fields of science and engineering. Computer time spent in solving partial differential equations is much more than that of in any other problem class. For this reason, partial differential equations are suitable to be solved on parallel computers that offer great computation power. In this study, parallel solution to partial differential equations with Jacobi, Gauss-Siedel, SOR (Succesive OverRelaxation and SSOR (Symmetric SOR algorithms is studied.
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
Generalized solutions of nonlinear partial differential equations
Rosinger, EE
1987-01-01
During the last few years, several fairly systematic nonlinear theories of generalized solutions of rather arbitrary nonlinear partial differential equations have emerged. The aim of this volume is to offer the reader a sufficiently detailed introduction to two of these recent nonlinear theories which have so far contributed most to the study of generalized solutions of nonlinear partial differential equations, bringing the reader to the level of ongoing research.The essence of the two nonlinear theories presented in this volume is the observation that much of the mathematics concernin
Analytic Solutions and Resonant Solutions of Hyperbolic Partial Differential Equations
Wagenmaker, Timothy Roger
This dissertation contains two main subject areas. The first deals with solutions to the wave equation Du/Dt + a Du/Dx = 0, where D/Dt and D/Dx represent partial derivatives and a(t,x) is real valued. The question I studied, which arises in control theory, is whether solutions which are real analytic with respect to the time variable are dense in the space of all solutions. If a is real analytic in t and x, the Cauchy-Kovalevsky Theorem implies that the solutions real analytic in t and x are dense, since it suffices to approximate the initial data by polynomials. The same positive result is valid when a is continuously differentiable and independent of t. This is proved by regularization in time. The hypothesis that a is independent of t cannot be replaced by the weaker assumption that a is real analytic in t, even when it is infinitely smooth. I construct a(t,x) for which the solutions which are analytic in time are automatically periodic in time. In particular these solutions are not dense in the space of all solutions. The second area concerns the resonant interaction of oscillatory waves propagating in a compressible inviscid fluid. An asymptotic description given by Andrew Majda, Rodolfo Rosales, and Maria Schonbek (MRS) involves the genuinely nonlinear quasilinear hyperbolic system Du/Dt + D(uu/2)/Dt + v = 0, Dv/Dt - D(vv/2)/Dt - u = 0. They performed many numerical simulations which indicated that small amplitude solutions of this system tend to evade shock formation, and conjectured that "smooth initial data with a sufficiently small amplitude never develop shocks throughout a long time interval of integration.". I proved that for smooth periodic U(x), V(x) and initial data u(0,x) = epsilonU(x), v(0,x) = epsilonV(x), the solution is smooth for time at least constant times | ln epsilon| /epsilon. This is longer than the lifetime order 1/ epsilon of the solution to the decoupled Burgers equations. The decoupled equation describes nonresonant interaction of
Solid solutions of hydrogen in niobium, molybdenum and their alloys
International Nuclear Information System (INIS)
Ishikawa, T.T.
1981-01-01
The solubility of hydrogen in niobium, molybdenum and niobium-molybdenum alloys with varying atomic fraction of molybdenum from 0.15 to 0.75 was measured on the temperature range of 673 0 K to 1273 0 k for one atmosphere hydrogen pressure. The experimental technique involved the saturation of the solvent metal or alloy with hydrogen, followed by quenching and analysis of the solid solution. The results obtained of hydrogen solubility are consistent with the quasi-regular model for the dilute interstitial solid solutions. The partial molar enthalpy and partial molar entropy in excess of the dissolved hydrogen atoms were calculated from data of solubility versus reciprocal doping temperature. The variation of the relative partial molar enthalpy of hydrogen dissolved in niobium-molybdenum alloys, with the increase of molybdenum content of the alloy was analized. (Author) [pt
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
Rusyaman, E.; Parmikanti, K.; Chaerani, D.; Asefan; Irianingsih, I.
2018-03-01
One of the application of fractional ordinary differential equation is related to the viscoelasticity, i.e., a correlation between the viscosity of fluids and the elasticity of solids. If the solution function develops into function with two or more variables, then its differential equation must be changed into fractional partial differential equation. As the preliminary study for two variables viscoelasticity problem, this paper discusses about convergence analysis of function sequence which is the solution of the homogenous fractional partial differential equation. The method used to solve the problem is Homotopy Analysis Method. The results show that if given two real number sequences (αn) and (βn) which converge to α and β respectively, then the solution function sequences of fractional partial differential equation with order (αn, βn) will also converge to the solution function of fractional partial differential equation with order (α, β).
Solid-soluted content of cerium in solid solution of sphene
International Nuclear Information System (INIS)
Zhao Wei; Teng Yuancheng; Li Yuxiang; Ren Xuetan; Huang Junjun
2010-01-01
The sphene solid solution was synthesized by solid-state method,with calcium carbonate, silica, titanium dioxide, cerium oxalate and alumina as raw materials. The solid-soluted content of cerium in sphene was researched by means of X-ray diffraction (XRD), backscattering scanning electron microscopy (BSE), energy dispersive spectroscopy (EDS) and so on. The influence of A l3+ ion introduction to sphene on the solid-soluted content of cerium in sphene solid solution was studied. The results indicate that when introducing Al 3+ to sphene as electrovalence compensation, Ce 4+ could be well solidified to Ca 1-x Ce x Ti 1-2x A l2x SiO 5 , and the solid-soluted content is approximately 12.61%. With no electrovalence compensation, Ce 4+ could be solidified to Ca 1-2x Ce x TiSiO 5 , and the solid-soluted content is approximately 10.98%. The appropriate synthesis temperature of sphene solid solution is 1 260 degree C.(authors)
Exact solutions of some nonlinear partial differential equations using ...
Indian Academy of Sciences (India)
The functional variable method is a powerful solution method for obtaining exact solutions of some nonlinear partial differential equations. In this paper, the functional variable method is used to establish exact solutions of the generalized forms of Klein–Gordon equation, the (2 + 1)-dimensional Camassa–Holm ...
Genetic algorithm solution for partial digest problem.
Ahrabian, Hayedeh; Ganjtabesh, Mohammad; Nowzari-Dalini, Abbas; Razaghi-Moghadam-Kashani, Zahra
2013-01-01
One of the fundamental problems in computational biology is the construction of physical maps of chromosomes from the hybridisation experiments between unique probes and clones of chromosome fragments. Before introducing the shotgun sequencing method, Partial Digest Problem (PDP) was an intractable problem used to construct the physical maps of DNA sequence in molecular biology. In this paper, we develop a novel Genetic Algorithm (GA) for solving the PDP. This algorithm is implemented and compared with well-known existing algorithms on different types of random and real instances data, and the obtained results show the efficiency of our algorithm. Also, our GA is adapted to handle the erroneous data and their efficiency is presented for the large instances of this problem.
Superhard Rhenium/Tungsten Diboride Solid Solutions.
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.
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
Analytical solutions for systems of partial differential-algebraic equations.
Benhammouda, Brahim; Vazquez-Leal, Hector
2014-01-01
This work presents the application of the power series method (PSM) to find solutions of partial differential-algebraic equations (PDAEs). Two systems of index-one and index-three are solved to show that PSM can provide analytical solutions of PDAEs in convergent series form. What is more, we present the post-treatment of the power series solutions with the Laplace-Padé (LP) resummation method as a useful strategy to find exact solutions. The main advantage of the proposed methodology is that the procedure is based on a few straightforward steps and it does not generate secular terms or depends of a perturbation parameter.
Mild Solutions of Neutral Stochastic Partial Functional Differential Equations
Directory of Open Access Journals (Sweden)
T. E. Govindan
2011-01-01
Full Text Available This paper studies the existence and uniqueness of a mild solution for a neutral stochastic partial functional differential equation using a local Lipschitz condition. When the neutral term is zero and even in the deterministic special case, the result obtained here appears to be new. An example is included to illustrate the theory.
Solution of partial differential equations by agent-based simulation
International Nuclear Information System (INIS)
Szilagyi, Miklos N
2014-01-01
The purpose of this short note is to demonstrate that partial differential equations can be quickly solved by agent-based simulation with high accuracy. There is no need for the solution of large systems of algebraic equations. This method is especially useful for quick determination of potential distributions and demonstration purposes in teaching electromagnetism. (letters and comments)
Bulk elastic wave propagation in partially saturated porous solids
International Nuclear Information System (INIS)
Berryman, J.G.; Thigpen, L.; Chin, R.C.Y.
1988-01-01
The linear equations of motion that describe the behavior of small disturbances in a porous solid containing both liquid and gas are solved for bulk wave propagation. The equations have been simplified by neglecting effects due to changes in capillary pressure. With this simplifying assumption, the equations reduce to two coupled (vector) equations of the form found in Biot's equations (for full saturation) but with more complicated coefficients. As in fully saturated solids, two shear waves with the same speed but different polarizations exist as do two compressional waves with distinct speeds. Attenuation effects can be enhanced in the partially saturated solid, depending on the distribution of gas in the pore space. Two models of the liquid/gas spatial distribution are considered: a segregated-fluids model and a mixed-fluids model. The two models predict comparable attentuation when the gas saturation is low, but the segregated-fluids model predicts a more rapid roll-off of attenuation as the gas saturation increases
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
On the Partial Analytical Solution of the Kirchhoff Equation
Michels, Dominik L.
2015-09-01
We derive a combined analytical and numerical scheme to solve the (1+1)-dimensional differential Kirchhoff system. Here the object is to obtain an accurate as well as an efficient solution process. Purely numerical algorithms typically have the disadvantage that the quality of solutions decreases enormously with increasing temporal step sizes, which results from the numerical stiffness of the underlying partial differential equations. To prevent that, we apply a differential Thomas decomposition and a Lie symmetry analysis to derive explicit analytical solutions to specific parts of the Kirchhoff system. These solutions are general and depend on arbitrary functions, which we set up according to the numerical solution of the remaining parts. In contrast to a purely numerical handling, this reduces the numerical solution space and prevents the system from becoming unstable. The differential Kirchhoff equation describes the dynamic equilibrium of one-dimensional continua, i.e. slender structures like fibers. We evaluate the advantage of our method by simulating a cilia carpet.
On the Partial Analytical Solution of the Kirchhoff Equation
Michels, Dominik L.; Lyakhov, Dmitry; Gerdt, Vladimir P.; Sobottka, Gerrit A.; Weber, Andreas G.
2015-01-01
We derive a combined analytical and numerical scheme to solve the (1+1)-dimensional differential Kirchhoff system. Here the object is to obtain an accurate as well as an efficient solution process. Purely numerical algorithms typically have the disadvantage that the quality of solutions decreases enormously with increasing temporal step sizes, which results from the numerical stiffness of the underlying partial differential equations. To prevent that, we apply a differential Thomas decomposition and a Lie symmetry analysis to derive explicit analytical solutions to specific parts of the Kirchhoff system. These solutions are general and depend on arbitrary functions, which we set up according to the numerical solution of the remaining parts. In contrast to a purely numerical handling, this reduces the numerical solution space and prevents the system from becoming unstable. The differential Kirchhoff equation describes the dynamic equilibrium of one-dimensional continua, i.e. slender structures like fibers. We evaluate the advantage of our method by simulating a cilia carpet.
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.
Structure of Partially Premixed Flames and Advanced Solid Propellants
National Research Council Canada - National Science Library
Branch, Melvyn
1998-01-01
The combustion of solid rocket propellants of advanced energetic materials involves a complex process of decomposition and condensed phase reactions in the solid propellant, gaseous flame reactions...
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
Superdiffusions and positive solutions of nonlinear partial differential equations
Dynkin, E B
2004-01-01
This book is devoted to the applications of probability theory to the theory of nonlinear partial differential equations. More precisely, it is shown that all positive solutions for a class of nonlinear elliptic equations in a domain are described in terms of their traces on the boundary of the domain. The main probabilistic tool is the theory of superdiffusions, which describes a random evolution of a cloud of particles. A substantial enhancement of this theory is presented that can be of interest for everybody who works on applications of probabilistic methods to mathematical analysis.
Calculation of similarity solutions of partial differential equations
International Nuclear Information System (INIS)
Dresner, L.
1980-08-01
When a partial differential equation in two independent variables is invariant to a group G of stretching transformations, it has similarity solutions that can be found by solving an ordinary differential equation. Under broad conditions, this ordinary differential equation is also invariant to another stretching group G', related to G. The invariance of the ordinary differential equation to G' can be used to simplify its solution, particularly if it is of second order. Then a method of Lie's can be used to reduce it to a first-order equation, the study of which is greatly facilitated by analysis of its direction field. The method developed here is applied to three examples: Blasius's equation for boundary layer flow over a flat plate and two nonlinear diffusion equations, cc/sub t/ = c/sub zz/ and c/sub t/ = (cc/sub z/)/sub z/
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
International Nuclear Information System (INIS)
Tao, D.P.
2004-01-01
Based on the free volume theory and the lattice model, the partition functions of pure solids and their mixtures were expressed. This resulted in the establishment of a thermodynamic model for solid solutions. The model naturally combines the excess entropy and excess enthalpy of a solution by means of new expressions of the configurational partition functions of solids and their mixtures derived from statistical thermodynamics, which is approximate to real solid solutions, that is S E ≠0 (V E ≠0) and H E ≠0. It can describe the thermodynamic properties of partially miscible systems and predict the thermodynamic properties in a multicomponent solid solution system using only the related binary infinite dilute activity coefficients. The predicted activity coefficients from the model are in good agreement with the experimental data of the ternary solid dilutions. This shows that the prediction effect of the proposed model is of better stability and reliability because it has a good physical basis
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)
Partial molar volume of anionic polyelectrolytes in aqueous solution.
Salamanca, Constain; Contreras, Martín; Gamboa, Consuelo
2007-05-15
In this work the partial molar volumes (V) of different anionic polyelectrolytes and hydrophobically modified polyelectrolytes (PHM) were measured. Polymers like polymaleic acid-co-styrene, polymaleic acid-co-1-olefin, polymaleic acid-co-vinyl-2-pyrrolidone, and polyacrylic acid (abbreviated as MAS-n, PA-n-K2, AMVP, and PAA, respectively) were employed. These materials were investigated by density measurements in highly dilute aqueous solutions. The molar volume results allow us to discuss the effect of the carboxylic groups and the contributions from the comonomeric principal chain. The PAA presents the smaller V, while the largest V value was for AMVP. The V of PHM shows a linear relationship with the number of methylene groups in the lateral chain. It is found that the magnitude of the contribution per methylene group decreases as the hydrophobic character of the environment increases.
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
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)
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)
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/
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.
Czech Academy of Sciences Publication Activity Database
Krisztin, T.; Rezunenko, Oleksandr
2016-01-01
Roč. 260, č. 5 (2016), s. 4454-4472 ISSN 0022-0396 R&D Projects: GA ČR GAP103/12/2431 Institutional support: RVO:67985556 Keywords : Parabolic partial differential equations * State dependent delay * Solution manifold Subject RIV: BC - Control Systems Theory Impact factor: 1.988, year: 2016 http://library.utia.cas.cz/separaty/2016/AS/rezunenko-0457879.pdf
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
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)
Grid generation for the solution of partial differential equations
Eiseman, Peter R.; Erlebacher, Gordon
1989-01-01
A general survey of grid generators is presented with a concern for understanding why grids are necessary, how they are applied, and how they are generated. After an examination of the need for meshes, the overall applications setting is established with a categorization of the various connectivity patterns. This is split between structured grids and unstructured meshes. Altogether, the categorization establishes the foundation upon which grid generation techniques are developed. The two primary categories are algebraic techniques and partial differential equation techniques. These are each split into basic parts, and accordingly are individually examined in some detail. In the process, the interrelations between the various parts are accented. From the established background in the primary techniques, consideration is shifted to the topic of interactive grid generation and then to adaptive meshes. The setting for adaptivity is established with a suitable means to monitor severe solution behavior. Adaptive grids are considered first and are followed by adaptive triangular meshes. Then the consideration shifts to the temporal coupling between grid generators and PDE-solvers. To conclude, a reflection upon the discussion, herein, is given.
CPDS3, Coupled 3-D Partial Differential Equation Solution
International Nuclear Information System (INIS)
Anderson, D.V.; Koniges, A.E.; Shumaker, D.E.
1992-01-01
1 - Description of program or function: CPDES3 solves the linear asymmetric matrix equations arising from coupled partial differential equations in three dimensions. The exact form of the matrix depends on the choice of spatial grids and on the finite element or finite difference approximation employed. CPDES3 allows each spatial operator to have 7, 15, 19, or 27 point stencils, permits general couplings between all of the component PDE's, and automatically generates the matrix structures needed to perform the algorithm. 2 - Method of solution: The resulting sparse matrix equation with a complicated sub-band structure and generally asymmetric is solved by either the preconditioned conjugate gradient (CG) method or the preconditioned bi-conjugate gradient (BCG) algorithm. BCG enjoys faster convergence in most cases but in rare instances diverges. Then, CG iterations must be used. 3 - Restrictions on the complexity of the problem: The discretization of the coupled three-dimensional PDE's and their boundary conditions must result in an operator stencil which fits in the Cray2 memory. In addition, the matrix must possess a reasonable amount of diagonal dominance for the preconditioning technique to be effective
CPDES2, Coupled 2-D Partial Differential Equation Solution
International Nuclear Information System (INIS)
Anderson, D.V.; Koniges, A.E.; Shumaker, D.E.
1992-01-01
1 - Description of program or function: CPDES2 solves the linear asymmetric equations arising from coupled partial differential equations in two dimensions. The exact form of the matrix depends on the choice of spatial grids and on the finite element or finite difference approximation employed. CPDES2 allows each spatial operator to have 5 or 9 point stencils, permits general coupling between all of the component PDE's, and automatically generates the matrix structures needed to perform the algorithm. 2 - Method of solution: The resulting sparse matrix equation with a complicated sub-band structure and generally asymmetric is solved by either the preconditioned conjugate gradient (CG) method or the preconditioned bi-conjugate gradient (BCG) algorithm. BCG enjoys faster convergence in most cases but in rare instances diverges. Then, CG iterations must be used. 3 - Restrictions on the complexity of the problem: The discretization of the coupled two-dimensional PDE's and their boundary conditions must result in an operator stencil which fits in the Cray2 memory. In addition, the matrix must possess a reasonable amount of diagonal dominance for the preconditioning technique to be effective
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
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.
Numerical solution of two-dimensional non-linear partial differential ...
African Journals Online (AJOL)
linear partial differential equations using a hybrid method. The solution technique involves discritizing the non-linear system of partial differential equations (PDEs) to obtain a corresponding nonlinear system of algebraic difference equations to be ...
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
Surface phase transitions in cu-based solid solutions
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.
Solute redistribution in dendritic solidification with diffusion in the solid
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.
Heterogeneous Ferroelectric Solid Solutions Phases and Domain States
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.
The generalized tanh method to obtain exact solutions of nonlinear partial differential equation
Gómez, César
2007-01-01
In this paper, we present the generalized tanh method to obtain exact solutions of nonlinear partial differential equations, and we obtain solitons and exact solutions of some important equations of the mathematical physics.
Exact solutions of some nonlinear partial differential equations using ...
Indian Academy of Sciences (India)
Nonlinear partial differential equations (NPDEs) are encountered in various ... such as physics, mechanics, chemistry, biology, mathematics and engineering. ... In §3, this method is applied to the generalized forms of Klein–Gordon equation,.
Structure and high-piezoelectricity in lead oxide solid solutions
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
Phase segregation in cerium-lanthanum solid solutions
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
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...
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
Graphene: A partially ordered non-periodic solid
International Nuclear Information System (INIS)
Wei, Dongshan; Wang, Feng
2014-01-01
Molecular dynamics simulations were performed to study the structural features of graphene over a wide range of temperatures from 50 to 4000 K using the PPBE-G potential [D. Wei, Y. Song, and F. Wang, J. Chem. Phys. 134, 184704 (2011)]. This potential was developed by force matching the Perdew-Burke-Ernzerhof (PBE) exchange correlation functional and has been validated previously to provide accurate potential energy surface for graphene at temperatures as high as 3000 K. Simulations with the PPBE‑G potential are the best available approximation to a direct Car-Parrinello Molecular Dynamics study of graphene. One advantage of the PBE-G potential is to allow large simulation boxes to be modeled efficiently so that properties showing strong finite size effects can be studied. Our simulation box contains more than 600 000 C atoms and is one of the largest graphene boxes ever modeled. With the PPBE-G potential, the thermal-expansion coefficient is negative up to 4000 K. With a large box and an accurate potential, the critical exponent for the scaling properties associated with the normal-normal and height-height correlation functions was confirmed to be 0.85. This exponent remains constant up to 4000 K suggesting graphene to be in the deeply cooled regime even close to the experimental melting temperature. The reduced peak heights in the radial distribution function of graphene show an inverse power law dependence to distance, which indicates that a macroscopic graphene sheet will lose long-range crystalline order as predicted by the Mermin-Wagner instability. Although graphene loses long-range translational order, it retains long range orientational order as indicated by its orientational correlation function; graphene is thus partially ordered but not periodic
Nonlocal symmetry generators and explicit solutions of some partial differential equations
International Nuclear Information System (INIS)
Qin Maochang
2007-01-01
The nonlocal symmetry of a partial differential equation is studied in this paper. The partial differential equation written as a conservation law can be transformed into an equivalent system by introducing a suitable potential. The nonlocal symmetry group generators of original partial differential equations can be obtained through their equivalent system. Further, new explicit solutions can be constructed from the newly obtained symmetry generators. The Burgers equation is chosen as an example; many new valuable explicit solutions and nonlocal symmetry generators are presented
Shear-induced partial translational ordering of a colloidal solid
Ackerson, B. J.; Clark, N. A.
1984-08-01
Highly charged submicrometer plastic spheres suspended in water at low ionic strength will order spontaneously into bcc crystals or polycrystals. A simple linear shear orients and disorders these crystals by forcing (110) planes to stack normal to the shear gradient and to slide relative to each other with a direction parallel to the solvent flow. In this paper we analyze in detail the disordering and flow processes occurring beyond the intrinsic elastic limit of the bcc crystal. We are led to a model in which the flow of a colloidal crystal is interpreted as a fundamentally different process from that found in atomic crystals. In the colloidal crystal the coupling of particle motion to the background fluid forces a homogeneous flow, where every layer is in motion relative to its neighboring layers. In contrast, the plastic flow in an atomic solid is defect mediated flow. At the lowest applied stress, the local bcc order in the colloidal crystal exhibits shear strains both parallel and perpendicular to the direction of the applied stress. The magnitude of these deformations is estimated using the configurational energy for bcc and distorted bcc crystals, assuming a screened Coulomb pair interaction between colloidal particles. As the applied stress is increased, the intrinsic elastic limit of the crystal is exceeded and the crystal begins to flow with adjacent layers executing an oscillatory path governed by the balance of viscous and screened Coulomb forces. The path takes the structure from the bcc1 and bcc2 twins observed at zero shear to a distorted two-dimensional hcp structure at moderate shear rates, with a loss of interlayer registration as the shear is increased. This theoretical model is consistent with other experimental observations, as well.
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
Engineering Solution for the Uniform Strength of Partially Cracked Concrete
DEFF Research Database (Denmark)
Hansen, Elin A.; Hansen, Will; Brincker, Rune
2005-01-01
Significant computational resources are required to predict the remaining strength from numerical fracture analysis of a jointed plain concrete pavement that contains a partial depth crack. It is, therefore, advantageous when the failure strength can be adequately predicted with an engineering...
Elastic interaction of partially debonded circular inclusions. I. Theoretical solution
DEFF Research Database (Denmark)
Kushch, V.I.; Shmegera, S.V.; Mishnaevsky, Leon
2010-01-01
and provides a simple and rapidly convergent iterative algorithm. The presented numerical data show an accuracy and numerical efficiency of the proposed method and discover the way and extent to which the elastic interaction between the partially debonded inclusions affects the local fields, stress intensity...... factors and the energy release rate at the interface crack tips....
Pure soliton solutions of some nonlinear partial differential equations
International Nuclear Information System (INIS)
Fuchssteiner, B.
1977-01-01
A general approach is given to obtain the system of ordinary differential equations which determines the pure soliton solutions for the class of generalized Korteweg-de Vries equations. This approach also leads to a system of ordinary differential equations for the pure soliton solutions of the sine-Gordon equation. (orig.) [de
Intuitive Understanding of Solutions of Partially Differential Equations
Kobayashi, Y.
2008-01-01
This article uses diagrams that help the observer see how solutions of the wave equation and heat conduction equation are obtained. The analytical approach cannot necessarily show the mechanisms of the key to the solution without transforming the differential equation into a more convenient form by separation of variables. The visual clues based…
Analytic continuation of solutions of some nonlinear convolution partial differential equations
Directory of Open Access Journals (Sweden)
Hidetoshi Tahara
2015-01-01
Full Text Available The paper considers a problem of analytic continuation of solutions of some nonlinear convolution partial differential equations which naturally appear in the summability theory of formal solutions of nonlinear partial differential equations. Under a suitable assumption it is proved that any local holomorphic solution has an analytic extension to a certain sector and its extension has exponential growth when the variable goes to infinity in the sector.
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. %)
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.
The solids-flux theory--confirmation and extension by using partial differential equations.
Diehl, Stefan
2008-12-01
The solids-flux theory has been used for half a century as a tool for estimating concentration and fluxes in the design and operation of secondary settling tanks during stationary conditions. The flux theory means that the conservation of mass is used in one dimension together with the batch-settling flux function according to the Kynch assumption. The flux theory results correspond to stationary solutions of a partial differential equation, a conservation law, with discontinuous coefficients modelling the continuous-sedimentation process in one dimension. The mathematical analysis of such an equation is intricate, partly since it cannot be interpreted in the classical sense. Recent results, however, make it possible to partly confirm and extend the previous flux theory statements, partly draw new conclusions also on the dynamic behaviour and the possibilities and limitations for control. We use here a single example of an ideal settling tank and a given batch-settling flux in a whole series of calculations. The mathematical results are adapted towards the application and many of them are conveniently presented in terms of operating charts.
Directory of Open Access Journals (Sweden)
Kunio Ichinobe
2015-01-01
Full Text Available We study the \\(k\\-summability of divergent formal solutions for the Cauchy problem of certain linear partial differential operators with coefficients which are polynomial in \\(t\\. We employ the method of successive approximation in order to construct the formal solutions and to obtain the properties of analytic continuation of the solutions of convolution equations and their exponential growth estimates.
International Nuclear Information System (INIS)
Zhang Huiqun
2009-01-01
By using some exact solutions of an auxiliary ordinary differential equation, a direct algebraic method is described to construct the exact complex solutions for nonlinear partial differential equations. The method is implemented for the NLS equation, a new Hamiltonian amplitude equation, the coupled Schrodinger-KdV equations and the Hirota-Maccari equations. New exact complex solutions are obtained.
Efimova, Olga Yu.
2010-01-01
The modification of simplest equation method to look for exact solutions of nonlinear partial differential equations is presented. Using this method we obtain exact solutions of generalized Korteweg-de Vries equation with cubic source and exact solutions of third-order Kudryashov-Sinelshchikov equation describing nonlinear waves in liquids with gas bubbles.
Analytic method for solitary solutions of some partial differential equations
Energy Technology Data Exchange (ETDEWEB)
Ugurlu, Yavuz [Firat University, Department of Mathematics, 23119 Elazig (Turkey); Kaya, Dogan [Firat University, Department of Mathematics, 23119 Elazig (Turkey)], E-mail: dkaya@firat.edu.tr
2007-10-22
In this Letter by considering an improved tanh function method, we found some exact solutions of the clannish random walker's parabolic equation, the modified Korteweg-de Vries (KdV) equation, and the Sharma-Tasso-Olver (STO) equation with its fission and fusion, the Jaulent-Miodek equation.
Analytic method for solitary solutions of some partial differential equations
International Nuclear Information System (INIS)
Ugurlu, Yavuz; Kaya, Dogan
2007-01-01
In this Letter by considering an improved tanh function method, we found some exact solutions of the clannish random walker's parabolic equation, the modified Korteweg-de Vries (KdV) equation, and the Sharma-Tasso-Olver (STO) equation with its fission and fusion, the Jaulent-Miodek equation
On evolving deformation microstructures in non-convex partially damaged solids
Gurses, Ercan; Miehe, Christian
2011-01-01
. These microstructures can be resolved by use of relaxation techniques associated with the construction of convex hulls. We propose a particular relaxation method for partially damaged solids and investigate it in one- and multi-dimensional settings. To this end, we
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...
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
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
Lectures on the Numerical Solution of Partial Differential Equations.
1981-12-01
Mathematics Rockefeller University Professor F. Brezzi New York, New York 10021 Laboratorio di Analisi Numerica Universita di Pavia Professor Amiram Harten...equations and to control the spacing of the points sj. In the MFE process the grid points move with the solution and cluster atound areas of roughness...149-159. [28] Fichera, G.: Analisi essistenziale per le soluzioni die problemi al contorno misti relativi alle equazione ed ai sistemi di equazioni
New Exact Solutions for New Model Nonlinear Partial Differential Equation
Maher, A.; El-Hawary, H. M.; Al-Amry, M. S.
2013-01-01
In this paper we propose a new form of Padé-II equation, namely, a combined Padé-II and modified Padé-II equation. The mapping method is a promising method to solve nonlinear evaluation equations. Therefore, we apply it, to solve the combined Padé-II and modified Padé-II equation. Exact travelling wave solutions are obtained and expressed in terms of hyperbolic functions, trigonometric functions, rational functions, and elliptic functions.
International Nuclear Information System (INIS)
Yao Ruo-Xia; Wang Wei; Chen Ting-Hua
2014-01-01
Motivated by the widely used ansätz method and starting from the modified Riemann—Liouville derivative together with a fractional complex transformation that can be utilized to transform nonlinear fractional partial differential equations to nonlinear ordinary differential equations, new types of exact traveling wave solutions to three important nonlinear space- and time-fractional partial differential equations are obtained simultaneously in terms of solutions of a Riccati equation. The results are new and first reported in this paper. (general)
Modeling Solution of Nonlinear Dispersive Partial Differential Equations using the Marker Method
International Nuclear Information System (INIS)
Lewandowski, Jerome L.V.
2005-01-01
A new method for the solution of nonlinear dispersive partial differential equations is described. The marker method relies on the definition of a convective field associated with the underlying partial differential equation; the information about the approximate solution is associated with the response of an ensemble of markers to this convective field. Some key aspects of the method, such as the selection of the shape function and the initial loading, are discussed in some details
International Nuclear Information System (INIS)
Li Xicheng; Xu Mingyu; Wang Shaowei
2008-01-01
In this paper, we give similarity solutions of partial differential equations of fractional order with a moving boundary condition. The solutions are given in terms of a generalized Wright function. The time-fractional Caputo derivative and two types of space-fractional derivatives are considered. The scale-invariant variable and the form of the solution of the moving boundary are obtained by the Lie group analysis. A comparison between the solutions corresponding to two types of fractional derivative is also given
Analytical Solutions for Systems of Singular Partial Differential-Algebraic Equations
Directory of Open Access Journals (Sweden)
U. Filobello-Nino
2015-01-01
Full Text Available This paper proposes power series method (PSM in order to find solutions for singular partial differential-algebraic equations (SPDAEs. We will solve three examples to show that PSM method can be used to search for analytical solutions of SPDAEs. What is more, we will see that, in some cases, Padé posttreatment, besides enlarging the domain of convergence, may be employed in order to get the exact solution from the truncated series solutions of PSM.
A Novel Method for Analytical Solutions of Fractional Partial Differential Equations
Mehmet Ali Akinlar; Muhammet Kurulay
2013-01-01
A new solution technique for analytical solutions of fractional partial differential equations (FPDEs) is presented. The solutions are expressed as a finite sum of a vector type functional. By employing MAPLE software, it is shown that the solutions might be extended to an arbitrary degree which makes the present method not only different from the others in the literature but also quite efficient. The method is applied to special Bagley-Torvik and Diethelm fractional differential equations as...
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
Synthesis and characterization of solid solutions in ABCO 4 system
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.
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
Penfold, Jeffrey; Thomas, Robert K; Li, Peixun; Xu, Hui; Tucker, Ian M; Petkov, Jordan T; Sivia, Devinderjit S
2015-06-23
Surface multilayer formation from the anionic-nonionic surfactant mixture of sodium dodecyl dioxyethylene sulfate, SLES, and monododecyl dodecaethylene glycol, C12E12, by the addition of multivalent Al(3+) counterions at the solid-solution interface is observed and characterized by neutron reflectivity, NR. The ability to form surface multilayer structures on hydrophobic and hydrophilic silica and cellulose surfaces is demonstrated. The surface multilayer formation is more pronounced and more well developed on the hydrophilic and hydrophobic silica surfaces than on the hydrophilic and hydrophobic cellulose surfaces. The less well developed multilayer formation on the cellulose surfaces is attributed to the greater surface inhomogeneities of the cellulose surface which partially inhibit lateral coherence and growth of the multilayer domains at the surface. The surface multilayer formation is associated with extreme wetting properties and offers the potential for the manipulation of the solid surfaces for enhanced adsorption and control of the wetting behavior.
Partial and total electronic stopping cross sections of atoms and solids for protons
International Nuclear Information System (INIS)
Kaneko, Toshiaki.
1990-12-01
Based on a wave packet theory (Phys. Rev. A40, 2188(1989); Phys. Stat. Sol. (B)156,49(1989)), partial and total electronic cross sections of target elements in atomic and solid phases with atomic number Z ranging from 2 (He) to 92 (U) are tabulated shell by shell for protons with velocity v from 0.2V 0 to 2OV 0 (V 0 =2.18 x 10 8 cm/s). (author)
Study of coupled nonlinear partial differential equations for finding exact analytical solutions.
Khan, Kamruzzaman; Akbar, M Ali; Koppelaar, H
2015-07-01
Exact solutions of nonlinear partial differential equations (NPDEs) are obtained via the enhanced (G'/G)-expansion method. The method is subsequently applied to find exact solutions of the Drinfel'd-Sokolov-Wilson (DSW) equation and the (2+1)-dimensional Painlevé integrable Burgers (PIB) equation. The efficiency of this method for finding these exact solutions is demonstrated. The method is effective and applicable for many other NPDEs in mathematical physics.
Study of coupled nonlinear partial differential equations for finding exact analytical solutions
Khan, Kamruzzaman; Akbar, M. Ali; Koppelaar, H.
2015-01-01
Exact solutions of nonlinear partial differential equations (NPDEs) are obtained via the enhanced (G′/G)-expansion method. The method is subsequently applied to find exact solutions of the Drinfel'd–Sokolov–Wilson (DSW) equation and the (2+1)-dimensional Painlevé integrable Burgers (PIB) equation. The efficiency of this method for finding these exact solutions is demonstrated. The method is effective and applicable for many other NPDEs in mathematical physics. PMID:26587256
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.
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
Institute of Scientific and Technical Information of China (English)
2008-01-01
Using functional derivative technique in quantum field theory, the algebraic dy-namics approach for solution of ordinary differential evolution equations was gen-eralized to treat partial differential evolution equations. The partial differential evo-lution equations were lifted to the corresponding functional partial differential equations in functional space by introducing the time translation operator. The functional partial differential evolution equations were solved by algebraic dynam-ics. The algebraic dynamics solutions are analytical in Taylor series in terms of both initial functions and time. Based on the exact analytical solutions, a new nu-merical algorithm—algebraic dynamics algorithm was proposed for partial differ-ential evolution equations. The difficulty of and the way out for the algorithm were discussed. The application of the approach to and computer numerical experi-ments on the nonlinear Burgers equation and meteorological advection equation indicate that the algebraic dynamics approach and algebraic dynamics algorithm are effective to the solution of nonlinear partial differential evolution equations both analytically and numerically.
Experimental and theoretical study of solid solution stability under irradiation
International Nuclear Information System (INIS)
Cauvin, Richard.
1981-08-01
The behavior of dilute alloys (Al-Zn, Al-Ag, Al-Si, Al-Ge and Al-Mg) under 1 MeV electron irradiation has been studied in a high voltage electron microscope. A phenomenon of homogeneous precipitation induced by irradiation in undersaturated solid solutions (Al-Zn, Al-Ag and Al-Si) has been discovered; the observed precipitates are either coherent or incoherent, but never associated with point defect sinks. The solubility limit is a function of irradiation temperature and flux; but, under irradiation, it does not behave as a true thermal solubility limit (without irradiation). The existing theories (kinetic or strictly thermodynamic) do not account for this phenomenon. It is shown that the irreversibility of the mutual recombination between trapped vacancies and mixed interstitials is the driving force of this homogeneous precipitation. Using a dilute solid solution model, we show that, under irradiation, the homogeneous stationary state, stable from a strictly thermodynamic point of view, can be unstable when the recombination reaction is taken into account. The solubility limit under irradiation is calculated with a nucleation-growth model taking account for this effect; it is proportional to the thermal solubility limit without irradiation. This model explains all the experimental observations [fr
Directory of Open Access Journals (Sweden)
Ji Juan-Juan
2017-01-01
Full Text Available A table lookup method for solving nonlinear fractional partial differential equations (fPDEs is proposed in this paper. Looking up the corresponding tables, we can quickly obtain the exact analytical solutions of fPDEs by using this method. To illustrate the validity of the method, we apply it to construct the exact analytical solutions of four nonlinear fPDEs, namely, the time fractional simplified MCH equation, the space-time fractional combined KdV-mKdV equation, the (2+1-dimensional time fractional Zoomeron equation, and the space-time fractional ZKBBM equation. As a result, many new types of exact analytical solutions are obtained including triangular periodic solution, hyperbolic function solution, singular solution, multiple solitary wave solution, and Jacobi elliptic function solution.
Reaction paths and equilibrium end-points in solid-solution aqueous-solution systems
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.
Nadjafikhah, Mehdi; Jafari, Mehdi
2014-01-01
In this paper, partially invariant solutions (PISs) method is applied in order to obtain new four-dimensional Einstein Walker manifolds. This method is based on subgroup classification for the symmetry group of partial differential equations (PDEs) and can be regarded as the generalization of the similarity reduction method. For this purpose, those cases of PISs which have the defect structure delta=1 and are resulted from two-dimensional subalgebras are considered in the present paper. Also ...
Partial and apparent molar volumes of aqueous solutions of the 1:1 type electrolytes
International Nuclear Information System (INIS)
Klugman, I.Yu.
2002-01-01
Formulas for calculating partial and apparent molar volumes of MX (M=Li-Cs; X = Cl-I) electrolyte aqueous solutions in a wide range of concentrations from 0 to 4 mol/kg with error not in excess of 0.05% are suggested. It is shown that the previously employed formulas for calculating partial molar volumes of electrolytes give false indications of mutual effect of ions and actually they are fit solely for very small concentrations [ru
The partial molar volume of BeSO4 in aqueous solutions
International Nuclear Information System (INIS)
Kuschel, F.; Seidel, J.
1981-01-01
The density of aqueous solutions of BeSO 4 has been measured as a function of the mole fraction in the range of 0.02487 x 10 -2 to 6.3082 x 10 -2 . From the results obtained the molar volume and partial molar volume have been calculated and the limiting value of the partial molar volume for Be 2+ was extrapolated in accordance with the Debye-Hueckel law
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.)
On evolving deformation microstructures in non-convex partially damaged solids
Gurses, Ercan
2011-06-01
The paper outlines a relaxation method based on a particular isotropic microstructure evolution and applies it to the model problem of rate independent, partially damaged solids. The method uses an incremental variational formulation for standard dissipative materials. In an incremental setting at finite time steps, the formulation defines a quasi-hyperelastic stress potential. The existence of this potential allows a typical incremental boundary value problem of damage mechanics to be expressed in terms of a principle of minimum incremental work. Mathematical existence theorems of minimizers then induce a definition of the material stability in terms of the sequential weak lower semicontinuity of the incremental functional. As a consequence, the incremental material stability of standard dissipative solids may be defined in terms of weak convexity notions of the stress potential. Furthermore, the variational setting opens up the possibility to analyze the development of deformation microstructures in the post-critical range of unstable inelastic materials based on energy relaxation methods. In partially damaged solids, accumulated damage may yield non-convex stress potentials which indicate instability and formation of fine-scale microstructures. These microstructures can be resolved by use of relaxation techniques associated with the construction of convex hulls. We propose a particular relaxation method for partially damaged solids and investigate it in one- and multi-dimensional settings. To this end, we introduce a new isotropic microstructure which provides a simple approximation of the multi-dimensional rank-one convex hull. The development of those isotropic microstructures is investigated for homogeneous and inhomogeneous numerical simulations. © 2011 Elsevier Ltd. All rights reserved.
International Nuclear Information System (INIS)
Blanco, Elena; Ruso, Juan M.; Prieto, Gerardo; Sarmiento, Felix
2005-01-01
Density and ultrasound measurements of sodium heptafluorobutyrate in aqueous solutions at T = (283.15, 288.15, 293.15, 298.15, 303.15, 308.15, 313.15, 318.15, and 323.15) K have been obtained. From these results partial molar volumes and isentropic partial molar adiabatic compressibilities were calculated. Deviations from the Debye-Hueckel limiting law provide evidence for limited association at lower concentrations. The change of the partial molar volume and isentropic partial molar adiabatic compressibility upon aggregation was calculated. Variations of the change of partial molar volumes and isentropic partial molar adiabatic compressibility upon aggregation are discussed in terms of temperature
Energy Technology Data Exchange (ETDEWEB)
Blanco, Elena [Group of Biophysics and Interfaces, Department of Applied Physics, Faculty of Physics, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain); Ruso, Juan M. [Group of Biophysics and Interfaces, Department of Applied Physics, Faculty of Physics, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain)]. E-mail: faruso@usc.es; Prieto, Gerardo [Group of Biophysics and Interfaces, Department of Applied Physics, Faculty of Physics, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain); Sarmiento, Felix [Group of Biophysics and Interfaces, Department of Applied Physics, Faculty of Physics, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain)
2005-12-15
Density and ultrasound measurements of sodium heptafluorobutyrate in aqueous solutions at T = (283.15, 288.15, 293.15, 298.15, 303.15, 308.15, 313.15, 318.15, and 323.15) K have been obtained. From these results partial molar volumes and isentropic partial molar adiabatic compressibilities were calculated. Deviations from the Debye-Hueckel limiting law provide evidence for limited association at lower concentrations. The change of the partial molar volume and isentropic partial molar adiabatic compressibility upon aggregation was calculated. Variations of the change of partial molar volumes and isentropic partial molar adiabatic compressibility upon aggregation are discussed in terms of temperature.
Directory of Open Access Journals (Sweden)
Wang Yongfei
2017-01-01
Full Text Available Radial forging combined with unidirectional compression (RFCUM is introduced in recrystallization and partial melting (RAP to fabricate semi-solid 6063 aluminum alloy, which can be defined as a process of RFCUM-RAP. In this study, the microstructures of semi-solid 6063 alloy prepared by semi-solid isothermal treatment (SSIT and RFCUM-RAP processes are investigated. The results show that, the solid grains of semi-solid alloy prepared by SSIT are large and irregular. However, solid grains of semi-solid billet prepared by RFCUC-RAP are fine and spherical. Additionally, during RFCUC-RAP process, with the increase of isothermal holding time, the shape of solid grain is more and more spherical, but the size of solid grain is gradually increased. To obtain ideal semi-solid microstructure, the optimal isothermal holding temperature and time are 630 °C and 5~10 min, respectively.
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.)
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
Directory of Open Access Journals (Sweden)
Teixeira Leonardo S. G.
2002-01-01
Full Text Available A PLS-2 multivariate calibration method has been developed for the simultaneous determination of iron, nickel and zinc in ternary mixtures by solid phase spectrophotometry associated with flow injection analysis. Fe(II, Ni(II and Zn(II form color complexes with 1-(2-thiazolylazo-2-naphthol (TAN, immobilized on a C18 bonded silica support, at pH 6.4. The proposed procedure is based on the different reaction/retention ratios of the studied ions on the solid support. Bilinear spectrophotometric data of the analytes, fixed in the solid support, were recorded in the 400-800 nm wavelength range as a function of time and a partial least squares (PLS-2 algorithm was used to predict results of synthetic samples. The calibration set employed was integrated by 8 ternary mixture standards and a blank solution. Mixtures containing 0.040 to 0.20 mg L-1, of each species, were successfully resolved, using 3 factors for each analyte and a restricted number of absorbance data obtained in the wavelength range from 560 to 650 nm.
Nadjafikhah, Mehdi; Jafari, Mehdi
2013-12-01
In this paper, partially invariant solutions (PISs) method is applied in order to obtain new four-dimensional Einstein Walker manifolds. This method is based on subgroup classification for the symmetry group of partial differential equations (PDEs) and can be regarded as the generalization of the similarity reduction method. For this purpose, those cases of PISs which have the defect structure δ=1 and are resulted from two-dimensional subalgebras are considered in the present paper. Also it is shown that the obtained PISs are distinct from the invariant solutions that obtained by similarity reduction method.
Soliton solution for nonlinear partial differential equations by cosine-function method
International Nuclear Information System (INIS)
Ali, A.H.A.; Soliman, A.A.; Raslan, K.R.
2007-01-01
In this Letter, we established a traveling wave solution by using Cosine-function algorithm for nonlinear partial differential equations. The method is used to obtain the exact solutions for five different types of nonlinear partial differential equations such as, general equal width wave equation (GEWE), general regularized long wave equation (GRLW), general Korteweg-de Vries equation (GKdV), general improved Korteweg-de Vries equation (GIKdV), and Coupled equal width wave equations (CEWE), which are the important soliton equations
FORSIM, Solution of Ordinary or Partial Differential Equation with Initial Conditions
International Nuclear Information System (INIS)
Carver, M.B.
1985-01-01
1 - Description of problem or function: FORSIM is a FORTRAN oriented simulation program which automates the continuous transient solution of systems of ordinary and/or partial differential equations. The user writes his equations in a FORTRAN subroutine, following prescribed rules, and loads this routine along with the executive routines. The executive routines then read in initial data supplied by the user and proceed with the integration. 2 - Method of solution: Partial differential equations are converted to coupled ordinary differential equations by suitable discretization formulae. Integration is done by variable order, variable step-size error controlled algorithms. 3 - Restrictions on the complexity of the problem - Maximum of: 1000 ordinary differential equations
International Nuclear Information System (INIS)
LaChapelle, J.
2004-01-01
A path integral is presented that solves a general class of linear second order partial differential equations with Dirichlet/Neumann boundary conditions. Elementary kernels are constructed for both Dirichlet and Neumann boundary conditions. The general solution can be specialized to solve elliptic, parabolic, and hyperbolic partial differential equations with boundary conditions. This extends the well-known path integral solution of the Schroedinger/diffusion equation in unbounded space. The construction is based on a framework for functional integration introduced by Cartier/DeWitt-Morette
A Novel Method for Analytical Solutions of Fractional Partial Differential Equations
Directory of Open Access Journals (Sweden)
Mehmet Ali Akinlar
2013-01-01
Full Text Available A new solution technique for analytical solutions of fractional partial differential equations (FPDEs is presented. The solutions are expressed as a finite sum of a vector type functional. By employing MAPLE software, it is shown that the solutions might be extended to an arbitrary degree which makes the present method not only different from the others in the literature but also quite efficient. The method is applied to special Bagley-Torvik and Diethelm fractional differential equations as well as a more general fractional differential equation.
Biomass hydrolysis inhibition at high hydrogen partial pressure in solid-state anaerobic digestion.
Cazier, E A; Trably, E; Steyer, J P; Escudie, R
2015-08-01
In solid-state anaerobic digestion, so-called ss-AD, biogas production is inhibited at high total solids contents. Such inhibition is likely caused by a slow diffusion of dissolved reaction intermediates that locally accumulate. In this study, we investigated the effect of H2 and CO2 partial pressure on ss-AD. Partial pressure of H2 and/or CO2 was artificially fixed, from 0 to 1 557mbars for H2 and from 0 to 427mbars for CO2. High partial pressure of H2 showed a significant effect on methanogenesis, while CO2 had no impact. At high [Formula: see text] , the overall substrate degradation decreased with no accumulation of metabolites from acidogenic bacteria, indicating that the hydrolytic activity was specifically impacted. Interestingly, such inhibition did not occur when CO2 was added with H2. This result suggests that CO2 gas transfer is probably a key factor in ss-AD from biomass. Copyright © 2015 Elsevier Ltd. All rights reserved.
Engineering solutions to the management of solid radioactive waste
International Nuclear Information System (INIS)
1991-01-01
The management of radioactive waste, its safe handling and ultimate disposal, is of vital concern to engineers in the nuclear industry. The international conference 'Engineering Solutions to the Management of Solid Radioactive Waste', organized by the Institution of Mechanical Engineers and held in Manchester in November 1991, provided a forum for the discussion and comparison of the different methods of waste management used in Europe and America. Papers presented and discussed included: the interaction between the design of containers for low level radioactive waste and the design of a deep repository, commercial low level waste disposal sites in the United States, and the development of radioactive waste monitoring systems at the Sellafield reprocessing complex. This volume is a collection of 22 papers presented at the conference. All are indexed separately. (author)
Applicability of Solid Solution Heat Treatments to Aluminum Foams
Directory of Open Access Journals (Sweden)
Miguel Rodríguez-Pérez
2012-12-01
Full Text Available Present research work evaluates the influence of both density and size on the treatability of Aluminum-based (6000 series foam-parts subjected to a typical solid solution heat treatment (water quenching. The results are compared with those obtained for the bulk alloy, evaluating the fulfilment of cooling requirements. Density of the foams was modeled by tomography analysis and the thermal properties calculated, based on validated density-scaled models. With this basis, cooling velocity maps during water quenching were predicted by finite element modeling (FEM in which boundary conditions were obtained by solving the inverse heat conduction problem. Simulations under such conditions have been validated experimentally. Obtained results address incomplete matrix hardening for foam-parts bigger than 70 mm in diameter with a density below 650 kg/m3. An excellent agreement has been found in between the predicted cooling maps and final measured microhardness profiles.
Arqub, Omar Abu; El-Ajou, Ahmad; Momani, Shaher
2015-07-01
Building fractional mathematical models for specific phenomena and developing numerical or analytical solutions for these fractional mathematical models are crucial issues in mathematics, physics, and engineering. In this work, a new analytical technique for constructing and predicting solitary pattern solutions of time-fractional dispersive partial differential equations is proposed based on the generalized Taylor series formula and residual error function. The new approach provides solutions in the form of a rapidly convergent series with easily computable components using symbolic computation software. For method evaluation and validation, the proposed technique was applied to three different models and compared with some of the well-known methods. The resultant simulations clearly demonstrate the superiority and potentiality of the proposed technique in terms of the quality performance and accuracy of substructure preservation in the construct, as well as the prediction of solitary pattern solutions for time-fractional dispersive partial differential equations.
Partial regularity of weak solutions to a PDE system with cubic nonlinearity
Liu, Jian-Guo; Xu, Xiangsheng
2018-04-01
In this paper we investigate regularity properties of weak solutions to a PDE system that arises in the study of biological transport networks. The system consists of a possibly singular elliptic equation for the scalar pressure of the underlying biological network coupled to a diffusion equation for the conductance vector of the network. There are several different types of nonlinearities in the system. Of particular mathematical interest is a term that is a polynomial function of solutions and their partial derivatives and this polynomial function has degree three. That is, the system contains a cubic nonlinearity. Only weak solutions to the system have been shown to exist. The regularity theory for the system remains fundamentally incomplete. In particular, it is not known whether or not weak solutions develop singularities. In this paper we obtain a partial regularity theorem, which gives an estimate for the parabolic Hausdorff dimension of the set of possible singular points.
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.
On the solution of elliptic partial differential equations on regions with corners
International Nuclear Information System (INIS)
Serkh, Kirill; Rokhlin, Vladimir
2016-01-01
In this paper we investigate the solution of boundary value problems on polygonal domains for elliptic partial differential equations. We observe that when the problems are formulated as the boundary integral equations of classical potential theory, the solutions are representable by series of elementary functions. In addition to being analytically perspicuous, the resulting expressions lend themselves to the construction of accurate and efficient numerical algorithms. The results are illustrated by a number of numerical examples.
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.
Solution properties of solid and liquid potassium-indium alloys
International Nuclear Information System (INIS)
Takenaka, T.; Saboungi, M.L.
1987-01-01
It was recently shown by a combination of electrical resistivity, thermodynamic, and structural measurements that equiatomic alloys formed between K or Na and either Bi, Sb, Te, or Pb show pronounced deviations from ordinary metallic behavior and from ideal solution behavior, e.g., small values for the electrical conductivity and sharp peaks for the Darken excess stability function. Physical explanation of this behavior has been advanced on the basis of the formation of complex structural species similar to those reported for the corresponding solid alloys. The authors have chosen K-In alloys for several reasons. Phase diagram considerations coupled with small electronegativity differences between K and In would lead one to predict small deviations from ideal behavior, thus, this system would be suitable to test for oddities in alloy solution behavior in systems which deviate little from ideal behavior. Others have demonstrated that the position of the peak in the electrical resistivity changed in going from Li to Na and to K in the following sequence X/sub In/ ≅ 0.25, 0.40, and 0.50, respectively. The thermodynamic properties of these alloys would be expected to present similar trends
Ebert, Marcelo R
2018-01-01
This book provides an overview of different topics related to the theory of partial differential equations. Selected exercises are included at the end of each chapter to prepare readers for the “research project for beginners” proposed at the end of the book. It is a valuable resource for advanced graduates and undergraduate students who are interested in specializing in this area. The book is organized in five parts: In Part 1 the authors review the basics and the mathematical prerequisites, presenting two of the most fundamental results in the theory of partial differential equations: the Cauchy-Kovalevskaja theorem and Holmgren's uniqueness theorem in its classical and abstract form. It also introduces the method of characteristics in detail and applies this method to the study of Burger's equation. Part 2 focuses on qualitative properties of solutions to basic partial differential equations, explaining the usual properties of solutions to elliptic, parabolic and hyperbolic equations for the archetypes...
Sharma, Nikesh; Pareek, Smita; Chaturvedi, Nitin; Dahiya, Ratna
2018-03-01
Solar photovoltaic (SPV) systems are steadily rising and considered as the best alternatives to meet the rising demand of energy. In developing countries like India, SPV’s contribution being a clean energy is the most favourable. However, experiences have shown that produced power of these systems is usually affected due to day, night, seasonal variations, insolation, partial shading conditions etc. Among these parameters, partial shading causes a huge reduction in output power of PV systems. This results in lack of confidence for this technology among users. Thus, it is important and a major challenge in PV systems to minimize the effect of partial shading on their energy production. The work in this paper aims to propose solutions for reconfiguration of solar photovoltaic arrays in order to reduce partial shading losses and thus to enhance power generation.
Directory of Open Access Journals (Sweden)
Yusuf Pandir
2013-01-01
Full Text Available We firstly give some new functions called generalized hyperbolic functions. By the using of the generalized hyperbolic functions, new kinds of transformations are defined to discover the exact approximate solutions of nonlinear partial differential equations. Based on the generalized hyperbolic function transformation of the generalized KdV equation and the coupled equal width wave equations (CEWE, we find new exact solutions of two equations and analyze the properties of them by taking different parameter values of the generalized hyperbolic functions. We think that these solutions are very important to explain some physical phenomena.
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
Studies on mixed metal oxides solid solutions as heterogeneous catalysts
Directory of Open Access Journals (Sweden)
H. R. Arandiyan
2009-03-01
Full Text Available In this work, a series of perovskite-type mixed oxide LaMo xV1-xO3+δ powder catalysts (x = 0, 0.1, 0.3, 0.5, 0.7, 0.9, and 1.0, with 0.5 < δ < 1.5, prepared by the sol-gel process and calcined at 750ºC, provide an attractive and effective alternative means of synthesizing materials with better control of morphology. Structures of resins obtained during the gel formation process by FT-IR spectroscopy and XRD analysis showed that all the LaMo xV1-xO3+δ samples are single phase perovskite-type solid solutions. The surface area (BET between 2.5 - 5.0 m²/g (x = 0.1 and 1.0 respectively increases with increasing Mo ratio in the samples. They show high purity, good chemical homogeneity, and lower calcinations temperatures as compared with the solid-state chemistry route. SEM coupled to EDS and thermogravimetric analysis/differential thermal analyses (TGA/DTA have been carried out in order to evaluate the homogeneity of the catalyst. Finally, the experimental studies show that the calcination temperature and Mo content exhibited a significant influence on catalytic activity. Among the LaMo xV1-xO3+δ samples, LaMo0.7V0.3O4.2 showed the best catalytic activity for the topic reaction and the best activity and stability for ethane reforming at 850ºC under 8 bar.
Combined solid state and solution NMR studies of α,ε-15N labeled bovine rhodopsin
International Nuclear Information System (INIS)
Werner, Karla; Lehner, Ines; Dhiman, Harpreet Kaur; Richter, Christian; Glaubitz, Clemens; Schwalbe, Harald; Klein-Seetharaman, Judith; Khorana, H. Gobind
2007-01-01
Rhodopsin is the visual pigment of the vertebrate rod photoreceptor cell and is the only member of the G protein coupled receptor family for which a crystal structure is available. Towards the study of dynamics in rhodopsin, we report NMR-spectroscopic investigations of α,ε- 15 N-tryptophan labeled rhodopsin in detergent micelles and reconstituted in phospholipids. Using a combination of solid state 13 C, 15 N-REDOR and HETCOR experiments of all possible 13 C' i-1 carbonyl/ 15 N i -tryptophan isotope labeled amide pairs, and H/D exchange 1 H, 15 N-HSQC experiments conducted in solution, we assigned chemical shifts to all five rhodopsin tryptophan backbone 15 N nuclei and partially to their bound protons. 1 H, 15 N chemical shift assignment was achieved for indole side chains of Trp35 1.30 and Trp175 4.65 . 15 N chemical shifts were found to be similar when comparing those obtained in the native like reconstituted lipid environment and those obtained in detergent micelles for all tryptophans except Trp175 4.65 at the membrane interface. The results suggest that the integrated solution and solid state NMR approach presented provides highly complementary information in the study of structure and dynamics of large membrane proteins like rhodopsin
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
Ding, Xiao-Li; Nieto, Juan J.
2017-11-01
In this paper, we consider the analytical solutions of coupling fractional partial differential equations (FPDEs) with Dirichlet boundary conditions on a finite domain. Firstly, the method of successive approximations is used to obtain the analytical solutions of coupling multi-term time fractional ordinary differential equations. Then, the technique of spectral representation of the fractional Laplacian operator is used to convert the coupling FPDEs to the coupling multi-term time fractional ordinary differential equations. By applying the obtained analytical solutions to the resulting multi-term time fractional ordinary differential equations, the desired analytical solutions of the coupling FPDEs are given. Our results are applied to derive the analytical solutions of some special cases to demonstrate their applicability.
International Nuclear Information System (INIS)
Garcia S, I.; Ramirez, F. M.
2010-01-01
The interaction of the herbicide paraquat dichloride (P Q, substrate) with p-tert-butylcalix arenas (L, receptor) was investigated in both the solution and solid states. The isolated paraquat calixarene complexes were characterised by UV-visible, 1 H NMR, ESI-Ms, Luminescence and IR spectroscopies and elemental analysis. The stoichiometry of complexes 1 and 2 was 1:1 (1 herbicide: 1 calixarene) and both revealed a biexponential luminescence decay with lifetimes depending on the size and the conformational particularity of the calixarenes. Molecular modelling suggested that both calixarenes interact with the herbicide through cation-π interaction. P Q in included in the p-tert butylcalix a rene cavity, a situation favoured by its pinched conformation in polar solvent while it is partially included in the p-tert butylcalix a rene cavity because of its in-out cone conformation. The theoretical results, in particular using Mopac procedures, were in agreement with the experimental findings. (Author)
Energy Technology Data Exchange (ETDEWEB)
Garcia S, I.; Ramirez, F. M., E-mail: flor.ramirez@inin.gob.m [ININ, Departamento de Quimica, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)
2010-07-01
The interaction of the herbicide paraquat dichloride (P Q, substrate) with p-tert-butylcalix arenas (L, receptor) was investigated in both the solution and solid states. The isolated paraquat calixarene complexes were characterised by UV-visible, {sup 1}H NMR, ESI-Ms, Luminescence and IR spectroscopies and elemental analysis. The stoichiometry of complexes 1 and 2 was 1:1 (1 herbicide: 1 calixarene) and both revealed a biexponential luminescence decay with lifetimes depending on the size and the conformational particularity of the calixarenes. Molecular modelling suggested that both calixarenes interact with the herbicide through cation-{pi} interaction. P Q in included in the p-tert butylcalix a rene cavity, a situation favoured by its pinched conformation in polar solvent while it is partially included in the p-tert butylcalix a rene cavity because of its in-out cone conformation. The theoretical results, in particular using Mopac procedures, were in agreement with the experimental findings. (Author)
Distribution of rare-earths in solid solution crandalita- goyazita of Sapucaia (Bonito-Para)
International Nuclear Information System (INIS)
Costa, M.L. da; Melo Costa, W.A. de
1987-01-01
The Crandallite are predominant in the lateritic phosphates of Sapucaia, in the form of the solid solution Crandallite (Cn)- Goyazite (Gz)-Florencite (Fl). The Crandallite-Goyazite is predominant, where the maximum proportion of Florencite is Cn 60 Cz 34.8 Fl 5.2 - This proportion of Florencite is relatively high for laterites, and for this case having up to 1,374% weight of TR 2 O 3 in the total sample. The light rare elements are predominant over the heavy ores, and are illustrated in the distribution curve normalized for the chondrites. This curve is partially comparable with the curve for Apatite presents slight negative anomaly for the element Europium, and slight positive anomaly for The elements Thulium. The geochemical caracteristics for the rare earths in this group allow the prediction for the original rock for the laterites. (author) [pt
Effect of Molecular Size of Solutes on Their Partial Molar Volumes in Supercritical n-Pentane
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
The densities of n-pentane, methane-n-pentane, propane-n-pentane, n-heptane-n-pentane, and n-decane-n-pentane binary mixtures were determined at 476.5K in the pressure range from 2 to 5 MPa. The partial molar volumes of the solutes in n-pentane were calculated using the density data. It was found that the partial molar volumes of methane and propane are positive , while those of n-heptane and n-decane are negative.
Sustainable solutions for solid waste management in Southeast Asian countries
International Nuclear Information System (INIS)
Uyen Nguyen Ngoc; Schnitzer, Hans
2009-01-01
Human activities generate waste and the amounts tend to increase as the demand for quality of life increases. Today's rate in the Southeast Asian Nations (ASEANs) is alarming, posing a challenge to governments regarding environmental pollution in the recent years. The expectation is that eventually waste treatment and waste prevention approaches will develop towards sustainable waste management solutions. This expectation is for instance reflected in the term 'zero emission systems'. The concept of zero emissions can be applied successfully with today's technical possibilities in the agro-based processing industry. First, the state-of-the-art of waste management in Southeast Asian countries will be outlined in this paper, followed by waste generation rates, sources, and composition, as well as future trends of waste. Further on, solutions for solid waste management will be reviewed in the discussions of sustainable waste management. The paper emphasizes the concept of waste prevention through utilization of all wastes as process inputs, leading to the possibility of creating an ecosystem in a loop of materials. Also, a case study, focusing on the citrus processing industry, is displayed to illustrate the application of the aggregated material input-output model in a widespread processing industry in ASEAN. The model can be shown as a closed cluster, which permits an identification of opportunities for reducing environmental impacts at the process level in the food processing industry. Throughout the discussion in this paper, the utilization of renewable energy and economic aspects are considered to adapt to environmental and economic issues and the aim of eco-efficiency. Additionally, the opportunities and constraints of waste management will be discussed.
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
Solid on liquid deposition, a review of technological solutions
Homsy, Alexandra; Laux, Edith; Jeandupeux, Laure; Charmet, Jérôme; Bitterli, Roland; Botta, Chiara; Rebetez, Yves; Banakh, Oksana; Keppner, Herbert
2015-01-01
Solid-on-liquid deposition (SOLID) techniques are of great interest to the MEMS and NEMS (Micro- and Nano Electro Mechanical Systems) community because of potential applications in biomedical engineering, on-chip liquid trapping, tunable micro-lenses, and replacements of gate oxides. However, depositing solids on liquid with subsequent hermetic sealing is difficult because liquids tend to have a lower density than solids. Furthermore, current systems seen in nature lack thermal, mechanical or...
Solid solution cermet: (Ti,Nb)(CN)-Ni cermet.
Kwon, Hanjung; Jung, Sun-A
2014-11-01
Solid solution powders without W, (Ti,Nb)(CN) powders with a B1 structure (NaCl like), were synthesized by high energy milling and carbothermal reduction in nitrogen. The range of molar ratios of Ti/Nb for forming complete (Ti,Nb)(CN) phase was broader than that of Ti/W for the (Ti,W)(CN) phase because carbide or carbonitride of Nb had a B1 crystal structure identical to Ti(CN) while WC had a hexagonal crystal structure. The results revealed that the hardness of (Ti,Nb)(CN)-Ni cermets was higher than that of (Ti,W)(CN)-Ni cermets. The lower density of the (Ti,Nb)(CN) powder contributed to the higher hardness compared to (Ti,W)(CN) because the volumetric ratio of (Ti,Nb)(CN) in the (Ti,Nb)(CN)-Ni cermets was higher than that of (Ti,Nb)(CN) in the (Ti,W)(CN)-Ni cermets at the same weight ratio of Ni. Additionally, it was assumed that intrinsic the properties of (Ti,Nb)(CN) could also be the cause for the high hardness of the (Ti,Nb)(CN)-Ni cermets.
A New Class of Ternary Compound for Lithium-Ion Battery: from Composite to Solid Solution.
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.
Talib, Imran; Belgacem, Fethi Bin Muhammad; Asif, Naseer Ahmad; Khalil, Hammad
2017-01-01
In this research article, we derive and analyze an efficient spectral method based on the operational matrices of three dimensional orthogonal Jacobi polynomials to solve numerically the mixed partial derivatives type multi-terms high dimensions generalized class of fractional order partial differential equations. We transform the considered fractional order problem to an easily solvable algebraic equations with the aid of the operational matrices. Being easily solvable, the associated algebraic system leads to finding the solution of the problem. Some test problems are considered to confirm the accuracy and validity of the proposed numerical method. The convergence of the method is ensured by comparing our Matlab software simulations based obtained results with the exact solutions in the literature, yielding negligible errors. Moreover, comparative results discussed in the literature are extended and improved in this study.
Note: Nonpolar solute partial molar volume response to attractive interactions with water.
Williams, Steven M; Ashbaugh, Henry S
2014-01-07
The impact of attractive interactions on the partial molar volumes of methane-like solutes in water is characterized using molecular simulations. Attractions account for a significant 20% volume drop between a repulsive Weeks-Chandler-Andersen and full Lennard-Jones description of methane interactions. The response of the volume to interaction perturbations is characterized by linear fits to our simulations and a rigorous statistical thermodynamic expression for the derivative of the volume to increasing attractions. While a weak non-linear response is observed, an average effective slope accurately captures the volume decrease. This response, however, is anticipated to become more non-linear with increasing solute size.
Note: Nonpolar solute partial molar volume response to attractive interactions with water
Energy Technology Data Exchange (ETDEWEB)
Williams, Steven M.; Ashbaugh, Henry S., E-mail: hanka@tulane.edu [Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, Louisiana 70118 (United States)
2014-01-07
The impact of attractive interactions on the partial molar volumes of methane-like solutes in water is characterized using molecular simulations. Attractions account for a significant 20% volume drop between a repulsive Weeks-Chandler-Andersen and full Lennard-Jones description of methane interactions. The response of the volume to interaction perturbations is characterized by linear fits to our simulations and a rigorous statistical thermodynamic expression for the derivative of the volume to increasing attractions. While a weak non-linear response is observed, an average effective slope accurately captures the volume decrease. This response, however, is anticipated to become more non-linear with increasing solute size.
Energy Technology Data Exchange (ETDEWEB)
Nasir, P; Mather, A E
1977-12-01
An apparatus for the determination of the solubility of hydrogen sulfide, carbon dioxide, and their mixtures in ethanolamine solutions at low pressures is described. With this apparatus, the solubility of H/sub 2/S, CO/sub 2/ and their mixtures in aqueous solutions of monoethanolamine was measured at partial pressures between 0.001 kPa and 9 kPa at temperatures of 80 and 100/sup 0/C. The results for the mixture were compared with two methods of prediction based on a thermodynamic model. 6 figures, 4 tables.
Chen, Shanzhen; Jiang, Xiaoyun
2012-08-01
In this paper, analytical solutions to time-fractional partial differential equations in a multi-layer annulus are presented. The final solutions are obtained in terms of Mittag-Leffler function by using the finite integral transform technique and Laplace transform technique. In addition, the classical diffusion equation (α=1), the Helmholtz equation (α→0) and the wave equation (α=2) are discussed as special cases. Finally, an illustrative example problem for the three-layer semi-circular annular region is solved and numerical results are presented graphically for various kind of order of fractional derivative.
Student Solutions Manual to Boundary Value Problems and Partial Differential Equations
Powers, David L
2005-01-01
This student solutions manual accompanies the text, Boundary Value Problems and Partial Differential Equations, 5e. The SSM is available in print via PDF or electronically, and provides the student with the detailed solutions of the odd-numbered problems contained throughout the book.Provides students with exercises that skillfully illustrate the techniques used in the text to solve science and engineering problemsNearly 900 exercises ranging in difficulty from basic drills to advanced problem-solving exercisesMany exercises based on current engineering applications
"Real-Time Optical Laboratory Linear Algebra Solution Of Partial Differential Equations"
Casasent, David; Jackson, James
1986-03-01
A Space Integrating (SI) Optical Linear Algebra Processor (OLAP) employing space and frequency-multiplexing, new partitioning and data flow, and achieving high accuracy performance with a non base-2 number system is described. Laboratory data on the performance of this system and the solution of parabolic Partial Differential Equations (PDEs) is provided. A multi-processor OLAP system is also described for the first time. It use in the solution of multiple banded matrices that frequently arise is then discussed. The utility and flexibility of this processor compared to digital systolic architectures should be apparent.
Numerical solutions of ordinary and partial differential equations in the frequency domain
International Nuclear Information System (INIS)
Hazi, G.; Por, G.
1997-01-01
Numerical problems during the noise simulation in a nuclear power plant are discussed. The solutions of ordinary and partial differential equations are studied in the frequency domain. Numerical methods by the transfer function method are applied. It is shown that the correctness of the numerical methods is limited for ordinary differential equations in the frequency domain. To overcome the difficulties, step-size selection is suggested. (author)
Directory of Open Access Journals (Sweden)
Hui-Sheng Ding
2013-04-01
Full Text Available In this paper, we first introduce a new class of pseudo almost periodic type functions and investigate some properties of pseudo almost periodic type functions; and then we discuss the existence of pseudo almost periodic solutions to the class of abstract partial functional differential equations $x'(t=Ax(t+f(t,x_t$ with finite delay in a Banach space X.
Increasing Weldability of Service-Aged Reformer Tubes by Partial Solution Annealing
Mostafaei, M.; Shamanian, M.; Purmohamad, H.; Amini, M.
2016-04-01
A dissimilar joint of 25Cr-35Ni/30Cr-48Ni (HP/HV) heat-resistant steels was evaluated. The investigations indicated that the as-cast HP alloy contained M7C3, M23C6, and NbC carbides and HV alloy with 5 wt.% tungsten, contained M23C6 and M6C carbides embedded in an austenitic matrix. After 8 years of ex-service aging at 1050 °C, the ductility of HP/HV reformer tubes was decreased dramatically, and thus, the repair welding of the aged HP/HV dissimilar joint was at a risk. In order to repair the aged reformer tubes and increase weldability properties, a new partial solution annealing treatment was designed. Mechanical testing results showed that partial solution annealing at 1200 °C for 6 h increased the elongation and toughness of the aged HP and HV alloys drastically. Also, a mechanism for constitutional liquation cracking in the heat-affected zones (HAZ) of the HP/HV dissimilar joint was proposed. In the HAZ of the aged HP/HV welded joint, the cracks around the locally melted carbides were initiated and propagated during carbides solidification at the cooling cycle of welding associated with the decrease in the ductility of the aged HP and HV alloys. In addition, Varestraint weldability test showed that the susceptibility to hot cracking was decreased with partial solution annealing.
Sadeghi, Fatemeh; Torab, Mansour; Khattab, Mostafa; Homayouni, Alireza; Afrasiabi Garekani, Hadi
2013-01-01
Objective(s): This study was performed aiming to investigate the effect of particle engineering via spray drying of hydroalcoholic solution on solid states and physico-mechanical properties of acetaminophen. Materials and Methods: Spray drying of hydroalcoholic solution (25% v/v ethanol/water) of acetaminophen (5% w/v) in the presence of small amounts of polyninylpyrrolidone K30 (PVP) (0, 1.25, 2.5 and 5% w/w based on acetaminophen weight) was carried out. The properties of spray dried particles namely morphology, surface characteristics, particle size, crystallinity, dissolution rate and compactibility were evaluated. Results: Spray drying process significantly changed the morphology of acetaminophen crystals from acicular (rod shape) to spherical microparticle. Differential scanning calorimetery (DSC) and x-ray powder diffraction (XRPD) studies ruled out any polymorphism in spray dried samples, however, a major reduction in crystallinity up to 65%, especially for those containing 5% w/w PVP was observed. Spray dried acetaminophen particles especially those obtained in the presence of PVP exhibited an obvious improvement of the dissolution and compaction properties. Tablets produced from spray dried samples exhibited excellent crushing strengths and no tendency to cap. Conclusions: The findings of this study revealed that spray drying of acetaminophen from hydroalcoholic solution in the presence of small amount of PVP produced partially amorphous particles with improved dissolution and excellent compaction properties. PMID:24379968
Convergence of exterior solutions to radial Cauchy solutions for $\\partial_t^2U-c^2\\Delta U=0$
Directory of Open Access Journals (Sweden)
Helge Kristian Jenssen
2016-09-01
Full Text Available Consider the Cauchy problem for the 3-D linear wave equation $\\partial_t^2U-c^2\\Delta U=0$ with radial initial data $U(0,x=\\Phi(x=\\varphi(|x|$, $U_t(0,x=\\Psi(x=\\psi(|x|$. A standard result states that $U$ belongs to $C([0,T];H^s(\\mathbb{R}^3$ whenever $(\\Phi,\\Psi\\in H^s\\times H^{s-1}(\\mathbb{R}^3$. In this article we are interested in the question of how U can be realized as a limit of solutions to initial-boundary value problems on the exterior of vanishing balls $B_\\varepsilon$ about the origin. We note that, as the solutions we compare are defined on different domains, the answer is not an immediate consequence of $H^s$ well-posedness for the wave equation.
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...
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
Solutions to an advanced functional partial differential equation of the pantograph type.
Zaidi, Ali A; Van Brunt, B; Wake, G C
2015-07-08
A model for cells structured by size undergoing growth and division leads to an initial boundary value problem that involves a first-order linear partial differential equation with a functional term. Here, size can be interpreted as DNA content or mass. It has been observed experimentally and shown analytically that solutions for arbitrary initial cell distributions are asymptotic as time goes to infinity to a certain solution called the steady size distribution. The full solution to the problem for arbitrary initial distributions, however, is elusive owing to the presence of the functional term and the paucity of solution techniques for such problems. In this paper, we derive a solution to the problem for arbitrary initial cell distributions. The method employed exploits the hyperbolic character of the underlying differential operator, and the advanced nature of the functional argument to reduce the problem to a sequence of simple Cauchy problems. The existence of solutions for arbitrary initial distributions is established along with uniqueness. The asymptotic relationship with the steady size distribution is established, and because the solution is known explicitly, higher-order terms in the asymptotics can be readily obtained.
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
Global Classical Solutions for Partially Dissipative Hyperbolic System of Balance Laws
Xu, Jiang; Kawashima, Shuichi
2014-02-01
The basic existence theory of Kato and Majda enables us to obtain local-in-time classical solutions to generally quasilinear hyperbolic systems in the framework of Sobolev spaces (in x) with higher regularity. However, it remains a challenging open problem whether classical solutions still preserve well-posedness in the case of critical regularity. This paper is concerned with partially dissipative hyperbolic system of balance laws. Under the entropy dissipative assumption, we establish the local well-posedness and blow-up criterion of classical solutions in the framework of Besov spaces with critical regularity with the aid of the standard iteration argument and Friedrichs' regularization method. Then we explore the theory of function spaces and develop an elementary fact that indicates the relation between homogeneous and inhomogeneous Chemin-Lerner spaces (mixed space-time Besov spaces). This fact allows us to capture the dissipation rates generated from the partial dissipative source term and further obtain the global well-posedness and stability by assuming at all times the Shizuta-Kawashima algebraic condition. As a direct application, the corresponding well-posedness and stability of classical solutions to the compressible Euler equations with damping are also obtained.
International Nuclear Information System (INIS)
Liu Hongzhun; Pan Zuliang; Li Peng
2006-01-01
In this article, we will derive an equality, where the Taylor series expansion around ε = 0 for any asymptotical analytical solution of the perturbed partial differential equation (PDE) with perturbing parameter ε must be admitted. By making use of the equality, we may obtain a transformation, which directly map the analytical solutions of a given unperturbed PDE to the asymptotical analytical solutions of the corresponding perturbed one. The notion of Lie-Baecklund symmetries is introduced in order to obtain more transformations. Hence, we can directly create more transformations in virtue of known Lie-Baecklund symmetries and recursion operators of corresponding unperturbed equation. The perturbed Burgers equation and the perturbed Korteweg-de Vries (KdV) equation are used as examples.
A Local Composition Model for Paraffinic Solid Solutions
DEFF Research Database (Denmark)
Coutinho, A.P. João; Knudsen, Kim; Andersen, Simon Ivar
1996-01-01
The description of the solid-phase non-ideality remains the main obstacle in modelling the solid-liquid equilibrium of hydrocarbons. A theoretical model, based on the local composition concept, is developed for the orthorhombic phase of n-alkanes and tested against experimental data for binary sy...... systems. It is shown that it can adequately predict the experimental phase behaviour of paraffinic mixtures. This work extends the applicability of local composition models to the solid phase. Copyright (C) 1996 Elsevier Science Ltd....
Solid lipid nanoparticles suspension versus commercial solutions for dermal delivery of minoxidil.
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.
International Nuclear Information System (INIS)
Mihalas, D.; Shine, R.A.; Kunasz, P.B.; Hummer, D.G.
1976-01-01
An analysis of the effects of partial frequency redistribution in the scattering process for lines formed in moving atmospheres has been performed using a flexible and general method which allows solutions of the transfer equation in the comoving frame of the gas. As a specific example, we consider the same chromospheric and atomic model, with the same velocity field, that was studied by Cannon and Vardavas. We find that the large changes in the profiles obtained by those authors, between the cases of complete and partial redistribution are spurious effects of angle averaging in the observer's frame instead of the comoving frame. Our results support fully the conclusion by Magnan that these changes are, in fact, unreal, at least for this particular model and redistribution function. Future work with other redistribution functions and with nonmonotone velocity fields will be possible using the techniques developed in this paper
Photoinduced partial charge transfer between conjugated polymer and fullerene in solutions
International Nuclear Information System (INIS)
Lin Hongzhen; Weng Yufeng; Huang Hongmin; He Qingguo; Zheng Min; Bai Fenglian
2004-01-01
Photoinduced charge transfer between a conjugated polymer and C 60 and the related processes were investigated in dilute solutions. The substantial fluorescence quenching is correlated with the efficient exciton diffusion within the polymer chains, according to which a sphere-of-action mechanism is proposed. An emissive exciplex was found formed between the conjugated polymer and fullerene in a nonpolar solvent, indicating the occurrence of a photoinduced partial charge transfer process. The low-energy sites in the polymer are believed to play a crucial role in the partial charge transfer. The asymmetry of the exciplex provides a method for evaluating the tendency of photoinduced charge separation between the donor and the acceptor. This method allows screening candidates for photovoltaic applications
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
Iron site occupancies in magnetite-ulvospinel solid solution: A new approach using XMCD
Energy Technology Data Exchange (ETDEWEB)
Pearce, C. I.; Henderson, C. M. B.; Telling, N. D.; Pattrick, R. A.D.; Vaughan, D. J.; Charnock, J. M.; Arenholz, E.; Tuna, F.; Coker, V.S.; Laan, G. van der
2009-06-22
Ordering of Fe{sup 3+} and Fe{sup 2+} between octahedral (Oh) and tetrahedral (Td) sites in synthetic members of the magnetite (Fe{sub 3}O{sub 4}) - ulvoespinel (Fe{sub 2}TiO{sub 4}) solid-solution series was determined using Fe L{sub 2,3}-edge X-ray magnetic circular dichroism (XMCD) coupled with electron microprobe and chemical analysis, Ti L-edge spectroscopy, Fe K-edge EXAFS and XANES, Fe{sub 57} Moessbauer spectroscopy, and unit cell parameters. Microprobe analysis, cell edges and chemical FeO determinations showed that the bulk compositions of the samples were stoichiometric magnetite-ulvoespinel solid-solutions. Surface sensitive XMCD showed that the surfaces of these oxide minerals were more sensitive to redox conditions and some samples required re-equilibration with suitable solid-solid buffers. Detailed site-occupancy analysis of these samples gave XMCD-Fe{sup 2+}/Fe{sup 3+} ratios very close to stoichiometric values. L{sub 2,3}-edge spectroscopy showed that Ti{sup 4+} was restricted to Oh sites. XMCD results showed that significant Fe{sup 2+} only entered Td when the Ti content was > 0.40 apfu while Fe{sup 2+} in Oh increased from 1 a.p.f.u in magnetite to a maximum of {approx}1.4 apfu in USP45. As the Ti content increased from this point, the steady increase in Fe{sup 2+} in Td sites was clearly observable in the XMCD spectra, concurrent with a slow decrease in Fe{sup 2+} in Oh sites. Calculated magnetic moments showed a steady decrease from magnetite (4.06 {mu}{sub B}) to USP45 (1.5 {mu}{sub B}) and then a slower decrease towards the value for ulvoespinel (0 {mu}{sub B}). Two of the synthesized samples were also partially maghemitized by re-equilibrating with an oxidizing Ni-NiO buffer and XMCD showed that Fe{sup 2+} oxidation only occurred at Oh sites, with concomitant vacancy formation restricted to this site. This study shows the advantage of using XMCD as a direct measurement of Fe oxidation state in these complex magnetic spinels. These results
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
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
Solution of Nonlinear Partial Differential Equations by New Laplace Variational Iteration Method
Directory of Open Access Journals (Sweden)
Eman M. A. Hilal
2014-01-01
Full Text Available The aim of this study is to give a good strategy for solving some linear and nonlinear partial differential equations in engineering and physics fields, by combining Laplace transform and the modified variational iteration method. This method is based on the variational iteration method, Laplace transforms, and convolution integral, introducing an alternative Laplace correction functional and expressing the integral as a convolution. Some examples in physical engineering are provided to illustrate the simplicity and reliability of this method. The solutions of these examples are contingent only on the initial conditions.
Czech Academy of Sciences Publication Activity Database
Papež, Jan; Liesen, J.; Strakoš, Z.
2014-01-01
Roč. 449, 15 May (2014), s. 89-114 ISSN 0024-3795 R&D Projects: GA AV ČR IAA100300802; GA ČR GA201/09/0917 Grant - others:GA MŠk(CZ) LL1202; GA UK(CZ) 695612 Institutional support: RVO:67985807 Keywords : numerical solution of partial differential equations * finite element method * adaptivity * a posteriori error analysis * discretization error * algebra ic error * spatial distribution of the error Subject RIV: BA - General Mathematics Impact factor: 0.939, year: 2014
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
Bower, Dan J.; Sanan, Patrick; Wolf, Aaron S.
2018-01-01
The energy balance of a partially molten rocky planet can be expressed as a non-linear diffusion equation using mixing length theory to quantify heat transport by both convection and mixing of the melt and solid phases. Crucially, in this formulation the effective or eddy diffusivity depends on the entropy gradient, ∂S / ∂r , as well as entropy itself. First we present a simplified model with semi-analytical solutions that highlights the large dynamic range of ∂S / ∂r -around 12 orders of magnitude-for physically-relevant parameters. It also elucidates the thermal structure of a magma ocean during the earliest stage of crystal formation. This motivates the development of a simple yet stable numerical scheme able to capture the large dynamic range of ∂S / ∂r and hence provide a flexible and robust method for time-integrating the energy equation. Using insight gained from the simplified model, we consider a full model, which includes energy fluxes associated with convection, mixing, gravitational separation, and conduction that all depend on the thermophysical properties of the melt and solid phases. This model is discretised and evolved by applying the finite volume method (FVM), allowing for extended precision calculations and using ∂S / ∂r as the solution variable. The FVM is well-suited to this problem since it is naturally energy conserving, flexible, and intuitive to incorporate arbitrary non-linear fluxes that rely on lookup data. Special attention is given to the numerically challenging scenario in which crystals first form in the centre of a magma ocean. The computational framework we devise is immediately applicable to modelling high melt fraction phenomena in Earth and planetary science research. Furthermore, it provides a template for solving similar non-linear diffusion equations that arise in other science and engineering disciplines, particularly for non-linear functional forms of the diffusion coefficient.
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.
International Nuclear Information System (INIS)
Visitdumrongkul, Nuttawut; Tippawan, Phanicha; Authayanun, Suthida; Assabumrungrat, Suttichai; Arpornwichanop, Amornchai
2016-01-01
Highlights: • Process design of solid oxide electrolyzer integrated with a partial oxidation reactor is studied. • Effect of key operating parameters of partial oxidation reactor on the electrolyzer performance is presented. • Exergy analysis of the electrolyzer process is performed. • Partial oxidation reactor can enhance the solid oxide electrolyzer performance. • Partial oxidation reactor in the process is the highest exergy destruction unit. - Abstract: Hydrogen production without carbon dioxide emission has received a large amount of attention recently. A solid oxide electrolysis cell (SOEC) can produce pure hydrogen and oxygen via a steam electrolysis reaction that does not emit greenhouse gases. Due to the high operating temperature of SOEC, an external heat source is required for operation, which also helps to improve SOEC performance and reduce operating electricity. The non-catalytic partial oxidation reaction (POX), which is a highly exothermic reaction, can be used as an external heat source and can be integrated with SOEC. Therefore, the aim of this work is to study the effect of operating parameters of non-catalytic POX (i.e., the oxygen to carbon ratio, operating temperature and pressure) on SOEC performance, including exergy analysis of the process. The study indicates that non-catalytic partial oxidation can enhance the hydrogen production rate and efficiency of the system. In terms of exergy analysis, the non-catalytic partial oxidation reactor is demonstrated to be the highest exergy destruction unit due to irreversible chemical reactions taking place, whereas SOEC is a low exergy destruction unit. This result indicates that the partial oxidation reactor should be improved and optimally designed to obtain a high energy and exergy system efficiency.
Apparent and partial molal heat capacities of aqueous rare earth nitrate solutions at 250C
International Nuclear Information System (INIS)
Spedding, F.H.; Baker, J.L.; Walters, J.P.
1979-01-01
Specific heats of aqueous solutions of the trinitrates of La, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu were measured from 0.1 m to saturation at 25 0 C. Apparent molal heat capacities, phi/sub cp/, were calculated for these solutions, and empirical polynomial equations were obtained which expressed phi/sub cp/ as a function of m/sup 1/2/ for each salt. The partial molal heat capacities of the solvent, anti C 1 /sub p/, and solute, anti C 2 /sub p/, were calculated from these equations. Unlike chloride and perchlorate data reported earlier, values of anti C 1 /sub p/ for nitrate solutions across the rare earth series did not show a two series effect. Instead, anti C 1 /sub p/ values at lower concentrations (0.5 and 1.0 m) appear correlated with reported first formation constants for rare earth-nitrate complexes. 31 references, 9 figures, 2 tables
Sun, Shuyu; Salama, Amgad; El-Amin, Mohamed
2012-01-01
In this paper we introduce a new technique for the numerical solution of the various partial differential equations governing flow and transport phenomena in porous media. This method is proposed to be used in high level programming languages like
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...
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 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
Colloidal quantum dot solids for solution-processed solar cells
Yuan, Mingjian; Liu, Mengxia; Sargent, Edward H.
2016-01-01
Solution-processed photovoltaic technologies represent a promising way to reduce the cost and increase the efficiency of solar energy harvesting. Among these, colloidal semiconductor quantum dot photovoltaics have the advantage of a spectrally
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
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
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
Guo, Yugao; Zhao, He; Han, Yelin; Liu, Xia; Guan, Shan; Zhang, Qingyin; Bian, Xihui
2017-02-01
A simultaneous spectrophotometric determination method for trace heavy metal ions based on solid-phase extraction coupled with partial least squares approaches was developed. In the proposed method, trace metal ions in aqueous samples were adsorbed by cation exchange fibers and desorbed by acidic solution from the fibers. After the ion preconcentration process, the enriched solution was detected by ultraviolet and visible spectrophotometer (UV-Vis). Then, the concentration of heavy metal ions were quantified by analyzing ultraviolet and visible spectrum with the help of partial least squares (PLS) approaches. Under the optimal conditions of operation time, flow rate and detection parameters, the overlapped absorption peaks of mixed ions were obtained. The experimental data showed that the concentration, which can be calculated through chemometrics method, of each metal ion increased significantly. The heavy metal ions can be enriched more than 80-fold. The limits of detection (LOD) for the target analytes of copper ions (Cu2 +), cobalt ions (Co2 +) and nickel ions (Ni2 +) mixture was 0.10 μg L- 1, 0.15 μg L- 1 and 0.13 μg L- 1, respectively. The relative standard deviations (RSD) were less than 5%. The performance of the solid-phase extraction can enrich the ions efficiently and the combined method of spectrophotometric detection and PLS can evaluate the ions concentration accurately. The work proposed here is an interesting and promising attempt for the trace ions determination in water samples and will have much more applied field.
Experimental solid state NMR of gas hydrates : problems and solutions
Energy Technology Data Exchange (ETDEWEB)
Moudrakovski, I.; Lu, H.; Ripmeester, J. [National Research Council of Canada, Ottawa, ON (Canada). Steacie Inst. for Molecular Sciences; Kumar, R.; Susilo, R. [British Columbia Univ., Vancouver, BC (Canada). Dept. of Chemical and Biological Engineering; Luzi, M. [GeoForschungsZentrum Potsdam, Potsdam (Germany)
2008-07-01
Solid State NMR is a suitable spectroscopic technique for hydrate research for several reasons, including its capability to distinguish between different structural types of hydrates, its quantitative nature and potential for both in-situ and time resolved experiments. This study illustrated the applications of solid state NMR for compositional and structural studies of clathrate hydrates, with particular emphasis on experimental techniques and potential ways to overcome technical difficulties. In order to use the method to its full capacity, some instrumental developments are needed to adapt it to the specific experimental requirements of hydrate studies, such as very low temperatures and high pressures. This presentation discussed the quantification of the Carbon-13 spectra with examples from natural and synthetic hydrates prepared from multi-component mixtures of hydrocarbons. The main approach used for the first two examples was Carbon-13 NMR with Magic Angle Spinning (MAS) at -100 degrees C. The detailed characterization of mixed hydrogen hydrates required low temperature hydrogen MAS. The quantification problems encountered during these experiments were also discussed. The purpose of these recent experimental developments was to prompt wider application of Solid State NMR in hydrate research. NMR proved to be a viable method for analyzing the composition and structure of multi-component mixed gas hydrates; characterizing natural gas hydrates; and, evaluating the formation conditions and properties of mixed hydrogen hydrates. The limitations of the method were highlighted and sensible choices of experimental conditions and techniques that ensure accurate results were discussed. 34 refs., 10 figs.
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.
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.
International Nuclear Information System (INIS)
Fedorov, G.B.; Zhukov, V.P.; Braun, A.G.; Smirnov, E.A.
1974-01-01
From the electroresistivity variation at 77 0 K, the influence of nonequilibrium point defect density and of complexes and dislocations on the decay process of the iron-copper solid solution is determined. Owing to high quenching rate of thin foils, isochrones of their electroconductivity curves appear shifted by about 200 0 C to lower temperatures. For quenched and irradiated specimens at 200-250 0 C a sharp retardation of electroconductivity decline is observed due to a zone stage. The plastic deformation (15%) leads to a partial suppression of that stage. Both irradiation and deformation initiate the process of copper separation from the solid solution, the latter being the stronger, the more copper is in the solid solution
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)
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
Multiferroic properties in NdFeO3-PbTiO3 solid solutions
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.
Municipal solid waste management. Strategies and technologies for sustainable solutions
Energy Technology Data Exchange (ETDEWEB)
Ludwig, C.; Hellweg, S.; Stucki, S. (eds.)
2002-10-01
The way municipal solid waste is handled greatly determines its impact on the local as well as the global environment. New technologies habe emerged for the treatment of waste, for the recovery of raw materials and energy, and for safe final disposal. The environmental performance of technologies, their social acceptance and their economic viability are key issues to be considered in sustainable waste management. This book provides an overview of current practices in waste management and a synthesis of new developments achieved through interdisciplinary discussions of recent research results. (orig.)
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
Subdiffusion kinetics of nanoprecipitate growth and destruction in solid solutions
Sibatov, R. T.; Svetukhin, V. V.
2015-06-01
Based on fractional differential generalizations of the Ham and Aaron-Kotler precipitation models, we study the kinetics of subdiffusion-limited growth and dissolution of new-phase precipitates. We obtain the time dependence of the number of impurities and dimensions of new-phase precipitates. The solutions agree with the Monte Carlo simulation results.
A Solution Space for a System of Null-State Partial Differential Equations: Part 3
Flores, Steven M.; Kleban, Peter
2015-01-01
This article is the third of four that completely and rigorously characterize a solution space for a homogeneous system of 2 N + 3 linear partial differential equations (PDEs) in 2 N variables that arises in conformal field theory (CFT) and multiple Schramm-Löwner evolution (SLE κ ). The system comprises 2 N null-state equations and three conformal Ward identities that govern CFT correlation functions of 2 N one-leg boundary operators. In the first two articles (Flores and Kleban, in Commun Math Phys, arXiv:1212.2301, 2012; Commun Math Phys, arXiv:1404.0035, 2014), we use methods of analysis and linear algebra to prove that dim , with C N the Nth Catalan number. Extending these results, we prove in this article that dim and entirely consists of (real-valued) solutions constructed with the CFT Coulomb gas (contour integral) formalism. In order to prove this claim, we show that a certain set of C N such solutions is linearly independent. Because the formulas for these solutions are complicated, we prove linear independence indirectly. We use the linear injective map of Lemma 15 in Flores and Kleban (Commun Math Phys, arXiv:1212.2301, 2012) to send each solution of the mentioned set to a vector in , whose components we find as inner products of elements in a Temperley-Lieb algebra. We gather these vectors together as columns of a symmetric matrix, with the form of a meander matrix. If the determinant of this matrix does not vanish, then the set of C N Coulomb gas solutions is linearly independent. And if this determinant does vanish, then we construct an alternative set of C N Coulomb gas solutions and follow a similar procedure to show that this set is linearly independent. The latter situation is closely related to CFT minimal models. We emphasize that, although the system of PDEs arises in CFT in away that is typically non-rigorous, our treatment of this system here and in Flores and Kleban (Commun Math Phys, arXiv:1212.2301, 2012; Commun Math Phys, arXiv:1404
International Nuclear Information System (INIS)
Eliseeva, O.V.; Golubev, V.V.
2003-01-01
Concentration dependence of partial volumes, electric conductivity and viscosity of lithium nitrate and chloride solutions in methanol, propanol, isopropanol, butanol, isobutanol, pentanol and isopentanol at 298.15 K were studied by the methods of densimetry, conductometry and viscosimetry. Structural specific features of the solutions studied are discussed on the basis of the calculated volumetric characteristics of the substance dissolved and solvent [ru
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 %) .
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 .
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
composition of the spinel solid solution in different phase fields and imposed oxygen partial pressures. The results can be summarized by the equations: MgO + {beta}-Rh{sub 2}O{sub 3} {yields} MgRh{sub 2}O{sub 4}; {Delta}G{sup Ring-Operator }({+-} 1010)/J mol{sup -1} = - 32239 + 7.534T; 2MgO + RhO{sub 2} {yields} Mg{sub 2}RhO{sub 4}; {Delta}G{sup Ring-Operator }({+-} 1270)/J mol{sup -1} = 36427 - 4.163T; {Delta}G{sub M}/J mol{sup -1} = 2RT(x In x + (1 - x)In(1 - x)) + 4650x(1 - x), where {Delta}G Degree-Sign is the standard Gibbs free energy change for the reaction and {Delta}G{sub M} is the free energy of mixing of the spinel solid solution Mg{sub 1+x}Rh{sub 2-x}O{sub 4}.
Colloidal quantum dot solids for solution-processed solar cells
Yuan, Mingjian
2016-02-29
Solution-processed photovoltaic technologies represent a promising way to reduce the cost and increase the efficiency of solar energy harvesting. Among these, colloidal semiconductor quantum dot photovoltaics have the advantage of a spectrally tuneable infrared bandgap, which enables use in multi-junction cells, as well as the benefit of generating and harvesting multiple charge carrier pairs per absorbed photon. Here we review recent progress in colloidal quantum dot photovoltaics, focusing on three fronts. First, we examine strategies to manage the abundant surfaces of quantum dots, strategies that have led to progress in the removal of electronic trap states. Second, we consider new device architectures that have improved device performance to certified efficiencies of 10.6%. Third, we focus on progress in solution-phase chemical processing, such as spray-coating and centrifugal casting, which has led to the demonstration of manufacturing-ready process technologies.
International Nuclear Information System (INIS)
Matthes, W.K.
1998-01-01
The 'adjoint transport equation in its integro-differential form' is derived for the radiation damage produced by atoms injected into solids. We reduce it to the one-dimensional form and prepare it for a numerical solution by: --discretizing the continuous variables energy, space and direction, --replacing the partial differential quotients by finite differences and --evaluating the collision integral by a double sum. By a proper manipulation of this double sum the adjoint transport equation turns into a (very large) set of linear equations with tridiagonal matrix which can be solved by a special (simple and fast) algorithm. The solution of this set of linear equations contains complete information on a specified damage type (e.g. the energy deposited in a volume V) in terms of the function D(i,E,c,x) which gives the damage produced by all particles generated in a cascade initiated by a particle of type i starting at x with energy E in direction c. It is essential to remark that one calculation gives the damage function D for the complete ranges of the variables {i,E,c and x} (for numerical reasons of course on grid-points in the {E,c,x}-space). This is most useful to applications where a general source-distribution S(i,E,c,x) of particles is given by the experimental setup (e.g. beam-window and and target in proton accelerator work. The beam-protons along their path through the window--or target material generate recoil atoms by elastic collisions or nuclear reactions. These recoil atoms form the particle source S). The total damage produced then is eventually given by: D = (Σ)i ∫ ∫ ∫ S(i, E, c, x)*D(i, E, c, x)*dE*dc*dx A Fortran-77 program running on a PC-486 was written for the overall procedure and applied to some problems
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)
International Nuclear Information System (INIS)
Zaslawsky, M.; Kennedy, W.N.
1992-01-01
Mathematical solutions to the problem consisting of a partially-full waste tank subjected to seismic loading, embedded in soil, is classically difficult in that one has to address: soil-structure interaction, fluid-structure interaction, non-linear behavior of material, dynamic effects. Separating the problem and applying numerous assumptions will yield approximate solutions. This paper explores methods for generating these solutions accurately
Directory of Open Access Journals (Sweden)
Hasibun Naher
2012-01-01
Full Text Available We construct new analytical solutions of the (3+1-dimensional modified KdV-Zakharov-Kuznetsev equation by the Exp-function method. Plentiful exact traveling wave solutions with arbitrary parameters are effectively obtained by the method. The obtained results show that the Exp-function method is effective and straightforward mathematical tool for searching analytical solutions with arbitrary parameters of higher-dimensional nonlinear partial differential equation.
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
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
Parshad, Rana; Bayazit, Derviş; Barlow, Nathaniel S.; Prasad, V. Ramchandra
2011-01-01
We consider a reduced form pricing model for mortgage backed securities, formulated as a non-linear partial differential equation. We prove that the model possesses a weak solution. We then show that under additional regularity assumptions on the initial data, we also have a mild solution. This mild solution is shown to be a strong solution via further regularity arguments. We also numerically solve the reduced model via a Fourier spectral method. Lastly, we compare our numerical solution to real market data. We observe interestingly that the reduced model captures a number of recent market trends in this data, that have escaped previous models.
Fast solution of elliptic partial differential equations using linear combinations of plane waves.
Pérez-Jordá, José M
2016-02-01
Given an arbitrary elliptic partial differential equation (PDE), a procedure for obtaining its solution is proposed based on the method of Ritz: the solution is written as a linear combination of plane waves and the coefficients are obtained by variational minimization. The PDE to be solved is cast as a system of linear equations Ax=b, where the matrix A is not sparse, which prevents the straightforward application of standard iterative methods in order to solve it. This sparseness problem can be circumvented by means of a recursive bisection approach based on the fast Fourier transform, which makes it possible to implement fast versions of some stationary iterative methods (such as Gauss-Seidel) consuming O(NlogN) memory and executing an iteration in O(Nlog(2)N) time, N being the number of plane waves used. In a similar way, fast versions of Krylov subspace methods and multigrid methods can also be implemented. These procedures are tested on Poisson's equation expressed in adaptive coordinates. It is found that the best results are obtained with the GMRES method using a multigrid preconditioner with Gauss-Seidel relaxation steps.
A Solution Space for a System of Null-State Partial Differential Equations: Part 1
Flores, Steven M.; Kleban, Peter
2015-01-01
This article is the first of four that completely and rigorously characterize a solution space for a homogeneous system of 2 N + 3 linear partial differential equations (PDEs) in 2 N variables that arises in conformal field theory (CFT) and multiple Schramm-Löwner evolution (SLE). In CFT, these are null-state equations and conformal Ward identities. They govern partition functions for the continuum limit of a statistical cluster or loop-gas model, such as percolation, or more generally the Potts models and O( n) models, at the statistical mechanical critical point. (SLE partition functions also satisfy these equations.) For such a lattice model in a polygon with its 2 N sides exhibiting a free/fixed side-alternating boundary condition , this partition function is proportional to the CFT correlation function where the w i are the vertices of and where is a one-leg corner operator. (Partition functions for "crossing events" in which clusters join the fixed sides of in some specified connectivity are linear combinations of such correlation functions.) When conformally mapped onto the upper half-plane, methods of CFT show that this correlation function satisfies the system of PDEs that we consider. In this first article, we use methods of analysis to prove that the dimension of this solution space is no more than C N , the Nth Catalan number. While our motivations are based in CFT, our proofs are completely rigorous. This proof is contained entirely within this article, except for the proof of Lemma 14, which constitutes the second article (Flores and Kleban, in Commun Math Phys, arXiv:1404.0035, 2014). In the third article (Flores and Kleban, in Commun Math Phys, arXiv:1303.7182, 2013), we use the results of this article to prove that the solution space of this system of PDEs has dimension C N and is spanned by solutions constructed with the CFT Coulomb gas (contour integral) formalism. In the fourth article (Flores and Kleban, in Commun Math Phys, arXiv:1405
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} (0
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.
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.
The elastic solid solution model for minerals at high pressures and temperatures
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
On the electrodynamics of partial discharges in voids in solid dielectrics
DEFF Research Database (Denmark)
Pedersen, Aage
1989-01-01
It is suggested that a correct interpretation of partial-discharge transients can be obtained only through the concept of induced charge. The application of this concept enables a partial-discharge theory to be developed by means of which the influence of relevant void parameters can be assessed ...
Cutting solid figures by plane - analytical solution and spreadsheet implementation
Benacka, Jan
2012-07-01
In some secondary mathematics curricula, there is a topic called Stereometry that deals with investigating the position and finding the intersection, angle, and distance of lines and planes defined within a prism or pyramid. Coordinate system is not used. The metric tasks are solved using Pythagoras' theorem, trigonometric functions, and sine and cosine rules. The basic problem is to find the section of the figure by a plane that is defined by three points related to the figure. In this article, a formula is derived that gives the positions of the intersection points of such a plane and the figure edges, that is, the vertices of the section polygon. Spreadsheet implementations of the formula for cuboid and right rectangular pyramids are presented. The user can check his/her graphical solution, or proceed if he/she is not able to complete the section.
Soil solid-phase controls lead activity in soil solution.
Badawy, S H; Helal, M I D; Chaudri, A M; Lawlor, K; McGrath, S P
2002-01-01
Lead pollution of the environment is synonymous with civilization. It has no known biological function, and is naturally present in soil, but its presence in food crops is deemed undesirable. The concern regarding Pb is mostly due to chronic human and animal health effects, rather then phytotoxicity. However, not much is known about the chemistry and speciation of Pb in soils. We determined the activity of Pb2+, in near neutral and alkaline soils, representative of alluvial, desertic and calcareous soils of Egypt, using the competitive chelation method. Lead activity ranged from 10(-6.73) to 10(-4.83) M, and was negatively correlated with soil and soil solution pH (R2 = -0.92, P soil solution from the equation: log(Pb2+) = 9.9 - 2pH. A solubility diagram for the various Pb minerals found in soil was constructed using published thermodynamic data obtained from the literature, and our measured Pb2+ activities compared with this information. The measured Pb2+ activities were undersaturated with regard to the solubility of PbSiO3 in equilibrium with SiO2 (soil). However, they were supersaturated with regard to the solubilities of the Pb carbonate minerals PbCO3 (cerussite) and Pb3(CO3)2(OH)2 in equilibrium with atmospheric CO2 and hydroxide Pb(OH)2. They were also supersaturated with regard to the solubilities of the Pb phosphate minerals Pb3(PO4)2, Pb5(PO4)3OH, and Pb4O(PO4)2 in equilibrium with tricalcium phosphate and CaCO3. The activity of Pb2+ was not regulated by any mineral of known solubility in our soils, but possibly by a mixture of Pb carbonate and phosphate minerals.
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
A Solution Space for a System of Null-State Partial Differential Equations: Part 4
Flores, Steven M.; Kleban, Peter
2015-01-01
This article is the last of four that completely and rigorously characterize a solution space for a homogeneous system of 2 N + 3 linear partial differential equations in 2 N variables that arises in conformal field theory (CFT) and multiple Schramm-Löwner evolution (SLE). The system comprises 2 N null-state equations and three conformal Ward identities that govern CFT correlation functions of 2 N one-leg boundary operators. In the first two articles (Flores and Kleban in Commun Math Phys, 2012; Flores and Kleban, in Commun Math Phys, 2014), we use methods of analysis and linear algebra to prove that dim , with C N the Nth Catalan number. Using these results in the third article (Flores and Kleban, in Commun Math Phys, 2013), we prove that dim and is spanned by (real-valued) solutions constructed with the Coulomb gas (contour integral) formalism of CFT. In this article, we use these results to prove some facts concerning the solution space . First, we show that each of its elements equals a sum of at most two distinct Frobenius series in powers of the difference between two adjacent points (unless is odd, in which case a logarithmic term may appear). This establishes an important element in the operator product expansion for one-leg boundary operators, assumed in CFT. We also identify particular elements of , which we call connectivity weights, and exploit their special properties to conjecture a formula for the probability that the curves of a multiple-SLE process join in a particular connectivity. This leads to new formulas for crossing probabilities of critical lattice models inside polygons with a free/fixed side-alternating boundary condition, which we derive in Flores et al. (Partition functions and crossing probabilities for critical systems inside polygons, in preparation). Finally, we propose a reason for why the exceptional speeds [certain values that appeared in the analysis of the Coulomb gas solutions in Flores and Kleban (Commun Math Phys, 2013)] and
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
The LiBH_{4}-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...
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.
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.)
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
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.
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
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
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
International Nuclear Information System (INIS)
Leaf, G.K.; Minkoff, M.
1982-01-01
1 - Description of problem or function: DISPL1 is a software package for solving second-order nonlinear systems of partial differential equations including parabolic, elliptic, hyperbolic, and some mixed types. The package is designed primarily for chemical kinetics- diffusion problems, although not limited to these problems. Fairly general nonlinear boundary conditions are allowed as well as inter- face conditions for problems in an inhomogeneous medium. The spatial domain is one- or two-dimensional with rectangular Cartesian, cylindrical, or spherical (in one dimension only) geometry. 2 - Method of solution: The numerical method is based on the use of Galerkin's procedure combined with the use of B-Splines (C.W.R. de-Boor's B-spline package) to generate a system of ordinary differential equations. These equations are solved by a sophisticated ODE software package which is a modified version of Hindmarsh's GEAR package, NESC Abstract 592. 3 - Restrictions on the complexity of the problem: The spatial domain must be rectangular with sides parallel to the coordinate geometry. Cross derivative terms are not permitted in the PDE. The order of the B-Splines is at most 12. Other parameters such as the number of mesh points in each coordinate direction, the number of PDE's etc. are set in a macro table used by the MORTRAn2 preprocessor in generating the object code
International Nuclear Information System (INIS)
Moreno, Nicolás; Buchner, Richard; Vargas, Edgar F.
2015-01-01
Highlights: • Structural effects of the cations on surrounding water molecules are discussed. • Alkyl-chain geometry determines the hydration of Bu 4 N + isomers. • The “compactness” in the hydration shells varies significantly among the isomers. - Abstract: Values of apparent molar volume and isentropic compressibility of symmetric and asymmetric isomers of tetrabutylammonium bromide, namely tetra-n-butylammonium bromide, tetra-iso-butylammonium bromide, tetra-sec-butylammonium bromide, di-n-butyl-di-iso-butylammonium bromide and di-n-butyl-di-sec-butylammonium bromide, in aqueous solution were determined from density and speed of sound measurements. These properties were obtained as a function of molal concentration within the range of 0.01 < m/mol · kg −1 < 0.1 covering temperatures from 278.15 ⩽ T/K ⩽ 293.15. The partial molar volumes and the apparent isentropic molar compressibility at infinite dilution were calculated and their dependence on temperature examined. The results show that cations with sec-butyl chains have larger structural volumes compared to those with iso-butyl chains. In addition, cations with sec-butyl chains induce smaller structural changes in their hydration shell than the others
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.
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
Ene, Remus-Daniel; Marinca, Vasile; Marinca, Bogdan
2016-01-01
Analytic approximate solutions using Optimal Homotopy Perturbation Method (OHPM) are given for steady boundary layer flow over a nonlinearly stretching wall in presence of partial slip at the boundary. The governing equations are reduced to nonlinear ordinary differential equation by means of similarity transformations. Some examples are considered and the effects of different parameters are shown. OHPM is a very efficient procedure, ensuring a very rapid convergence of the solutions after only two iterations.
Chamorro, Diego; Lemarié-Rieusset, Pierre-Gilles; Mayoufi, Kawther
2018-04-01
We study the role of the pressure in the partial regularity theory for weak solutions of the Navier-Stokes equations. By introducing the notion of dissipative solutions, due to D uchon and R obert (Nonlinearity 13:249-255, 2000), we will provide a generalization of the Caffarelli, Kohn and Nirenberg theory. Our approach sheels new light on the role of the pressure in this theory in connection to Serrin's local regularity criterion.
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.
Energy Technology Data Exchange (ETDEWEB)
Werner, Karla; Lehner, Ines [Johann Wolfgang Goethe-Universitaet Frankfurt, Center for Biomolecular Magnetic Resonance (Germany); Dhiman, Harpreet Kaur [University of Pittsburgh School of Medicine, Department of Structural Biology (United States); Richter, Christian; Glaubitz, Clemens; Schwalbe, Harald, E-mail: schwalbe@nmr.uni-frankfurt.de; Klein-Seetharaman, Judith [Johann Wolfgang Goethe-Universitaet Frankfurt, Center for Biomolecular Magnetic Resonance (Germany); Khorana, H. Gobind [Massachusetts Institute of Technology, Departments of Biology and Chemistry (United States)], E-mail: khorana@mit.edu
2007-04-15
Rhodopsin is the visual pigment of the vertebrate rod photoreceptor cell and is the only member of the G protein coupled receptor family for which a crystal structure is available. Towards the study of dynamics in rhodopsin, we report NMR-spectroscopic investigations of {alpha},{epsilon}-{sup 15}N-tryptophan labeled rhodopsin in detergent micelles and reconstituted in phospholipids. Using a combination of solid state {sup 13}C,{sup 15}N-REDOR and HETCOR experiments of all possible {sup 13}C'{sub i-1} carbonyl/{sup 15}N{sub i}-tryptophan isotope labeled amide pairs, and H/D exchange {sup 1}H,{sup 15}N-HSQC experiments conducted in solution, we assigned chemical shifts to all five rhodopsin tryptophan backbone {sup 15}N nuclei and partially to their bound protons. {sup 1}H,{sup 15}N chemical shift assignment was achieved for indole side chains of Trp35{sup 1.30} and Trp175{sup 4.65}. {sup 15}N chemical shifts were found to be similar when comparing those obtained in the native like reconstituted lipid environment and those obtained in detergent micelles for all tryptophans except Trp175{sup 4.65} at the membrane interface. The results suggest that the integrated solution and solid state NMR approach presented provides highly complementary information in the study of structure and dynamics of large membrane proteins like rhodopsin.
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
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
International Nuclear Information System (INIS)
Tran Duc Van
1994-01-01
The notion of global quasi-classical solutions of the Cauchy problems for first-order nonlinear partial differential equations is presented, some uniqueness theorems and a stability result are established by the method based on the theory of differential inclusions. In particular, the answer to an open problem of S.N. Kruzhkov is given. (author). 10 refs, 1 fig
International Nuclear Information System (INIS)
Wang Qi; Chen Yong
2007-01-01
With the aid of symbolic computation, some algorithms are presented for the rational expansion methods, which lead to closed-form solutions of nonlinear partial differential equations (PDEs). The new algorithms are given to find exact rational formal polynomial solutions of PDEs in terms of Jacobi elliptic functions, solutions of the Riccati equation and solutions of the generalized Riccati equation. They can be implemented in symbolic computation system Maple. As applications of the methods, we choose some nonlinear PDEs to illustrate the methods. As a result, we not only can successfully obtain the solutions found by most existing Jacobi elliptic function methods and Tanh-methods, but also find other new and more general solutions at the same time
Khan, M. Naziruddin; Aldalbahi, Ali; Almohammedi, Abdullah
2018-03-01
Colloidal porous silicon (PSi) in different solvents was synthesized by simple chemical etching. Colloidal solutions were then prepared using different quantities of silicon wafer pieces (Pcs) and chloroplatinic (Pt) acid in catalyst solution. The effect on the properties of the colloidal solutions and composite rods were investigated using various optical characterization techniques. Absorption and photoluminescence (PL) intensity of the colloidal PSi solutions are observed to depend on the quantity of wafer Pcs, the Pt-solution, and the porosity formation on the wafer surface. The morphological structure of the PSi in a solvent and the solid-rod environments were studied using field-emission scanning electron microscopy (FE-SEM) and were observed to have different structures. A mono-oriented structure of PSi exists in tetrahydrofuran, which has stereo orientation in dioxane and dimethylsulfoxide (approximately 5-8 nm as confirmed using high resolution transmission electron microscopy). Subsequently, some colloidal PSi solutions were directly embedded in three types of sol-gel-based matrices, silica, ormosils (or organically modified silica) and polymer, which easily generated solid rods. Spontaneous emission (SE) of the PSi solutions and their composite rods were examined using a high power picosecond 355 nm laser source. The emitted PL and SE signals of the colloidal PSi solutions were dependent on the Pt volume, nature of the solvent, quantity of Si wafer piece, and pumping energy. The response of SE signals from the PSi composites rods is an interesting phenomenon, and such nanocomposites may be used for future research on light amplification.
Influence of Ce 0.68 Zr 0.32 O 2 solid solution on depositing ...
Indian Academy of Sciences (India)
Home; Journals; Bulletin of Materials Science; Volume 29; Issue 1. Influence of Ce0.68Zr0.32O2 solid solution on depositing -alumina washcoat on FeCrAl foils. Mei-Qing Shen Li-Wei Jia Wen-Long Zhou Jun Wang Ying Huang. Composites Volume 29 Issue 1 February 2006 pp 73-76 ...
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.
Defect structure of cubic solid solutions of alkaline earth and rare earth fluorides
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
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%.
The preparation method of solid boron solution in silicon carbide in the form of micro powder
International Nuclear Information System (INIS)
Pampuch, R.; Stobierski, L.; Lis, J.; Bialoskorski, J.; Ermer, E.
1993-01-01
The preparation method of solid boron solution in silicon carbide in the form of micro power has been worked out. The method consists in introducing mixture of boron, carbon and silicon and heating in the atmosphere of inert gas to the 1573 K
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
Solution and solid-phase halogen and C-H hydrogen bonding to perrhenate.
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.
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
Bridging phases at the morphotropic boundaries of lead oxide solid solutions
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 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 ...
Exact Solution of the Two-Level System and the Einstein Solid in the Microcanonical Formalism
Bertoldi, Dalia S.; Bringa, Eduardo M.; Miranda, E. N.
2011-01-01
The two-level system and the Einstein model of a crystalline solid are taught in every course of statistical mechanics and they are solved in the microcanonical formalism because the number of accessible microstates can be easily evaluated. However, their solutions are usually presented using the Stirling approximation to deal with factorials. In…
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.
First-Principles Modeling of ThO2 Solid Solutions with Oxides of Trivalent Cations
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.
International Nuclear Information System (INIS)
Kupka, F.
1997-11-01
This thesis deals with the extension of sparse grid techniques to spectral methods for the solution of partial differential equations with periodic boundary conditions. A review on boundary and initial-boundary value problems and a discussion on numerical resolution is used to motivate this research. Spectral methods are introduced by projection techniques, and by three model problems: the stationary and the transient Helmholtz equations, and the linear advection equation. The approximation theory on the hyperbolic cross is reviewed and its close relation to sparse grids is demonstrated. This approach extends to non-periodic problems. Various Sobolev spaces with dominant mixed derivative are introduced to provide error estimates for Fourier approximation and interpolation on the hyperbolic cross and on sparse grids by means of Sobolev norms. The theorems are immediately applicable to the stability and convergence analysis of sparse grid spectral methods. This is explicitly demonstrated for the three model problems. A variant of the von Neumann condition is introduced to simplify the stability analysis of the time-dependent model problems. The discrete Fourier transformation on sparse grids is discussed together with its software implementation. Results on numerical experiments are used to illustrate the performance of the new method with respect to the smoothness properties of each example. The potential of the method in mathematical modelling is estimated and generalizations to other sparse grid methods are suggested. The appendix includes a complete Fortran90 program to solve the linear advection equation by the sparse grid Fourier collocation method and a third-order Runge-Kutta routine for integration in time. (author)
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)
DEFF Research Database (Denmark)
Topakas, E.; Kalogeris, E.; Kekos, D.
2003-01-01
A number of factors affecting production of feruloyl esterase an enzyme that hydrolyse ester linkages of ferulic acid (FA) in plant cell walls, by the thermophylic fungus Sporotrichum thermophile under solid state fermentation (SSF) were investigated. Initial moisture content and type of carbon...
Directory of Open Access Journals (Sweden)
Padmavathi Tallapragada
2017-06-01
It can be concluded that the fungus M. sanguineus is a good source of amylase production under solid state fermentation. Application of amylase produced by M. sanguineus in detergent industry was also carried out and it was proven very effective in stain removal from the fabrics.
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.
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.
International Nuclear Information System (INIS)
Ibragimov, N Kh; Avdonina, E D
2013-01-01
The method of nonlinear self-adjointness, which was recently developed by the first author, gives a generalization of Noether's theorem. This new method significantly extends approaches to constructing conservation laws associated with symmetries, since it does not require the existence of a Lagrangian. In particular, it can be applied to any linear equations and any nonlinear equations that possess at least one local conservation law. The present paper provides a brief survey of results on conservation laws which have been obtained by this method and published mostly in recent preprints of the authors, along with a method for constructing exact solutions of systems of partial differential equations with the use of conservation laws. In most cases the solutions obtained by the method of conservation laws cannot be found as invariant or partially invariant solutions. Bibliography: 23 titles
Goldstein, M; Haussmann, W; Hayman, W; Rogge, L
1992-01-01
This volume consists of the proceedings of the NATO Advanced Research Workshop on Approximation by Solutions of Partial Differential Equations, Quadrature Formulae, and Related Topics, which was held at Hanstholm, Denmark. These proceedings include the main invited talks and contributed papers given during the workshop. The aim of these lectures was to present a selection of results of the latest research in the field. In addition to covering topics in approximation by solutions of partial differential equations and quadrature formulae, this volume is also concerned with related areas, such as Gaussian quadratures, the Pompelu problem, rational approximation to the Fresnel integral, boundary correspondence of univalent harmonic mappings, the application of the Hilbert transform in two dimensional aerodynamics, finely open sets in the limit set of a finitely generated Kleinian group, scattering theory, harmonic and maximal measures for rational functions and the solution of the classical Dirichlet problem. In ...
Filimonov, M. Yu.
2017-12-01
The method of special series with recursively calculated coefficients is used to solve nonlinear partial differential equations. The recurrence of finding the coefficients of the series is achieved due to a special choice of functions, in powers of which the solution is expanded in a series. We obtain a sequence of linear partial differential equations to find the coefficients of the series constructed. In many cases, one can deal with a sequence of linear ordinary differential equations. We construct classes of solutions in the form of convergent series for a certain class of nonlinear evolution equations. A new class of solutions of generalized Boussinesque equation with an arbitrary function in the form of a convergent series is constructed.
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.
A decontamination system for chemical weapons agents using a liquid solution on a solid sorbent.
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.
Directory of Open Access Journals (Sweden)
Shaw-Yang Yang Hund-Der Yeh
2012-01-01
Full Text Available This note develops a general mathematical model for describing the transient hydraulic head response for constant-head test, constant-flux test, and slug test in a radial confined aquifer system with a partially penetrating well. The Laplace-domain solution for the model is derived by applying the Laplace transform with respect to time and finite Fourier cosine transform with respect to the z-direction. This new solution has been shown to reduce to the constant-head test when discounting the wellbore storage and maintaining a constant well water level. This solution can also be reduced to the constant-flux test solution when discounting the wellbore storage and keeping a constant pumping rate in the well. Moreover, the solution becomes the slug test solution when there is no pumping in the well. This general solution can be used to develop a single computer code to estimate aquifer parameters if coupled with an optimization algorithm or to assess the effect of well partial penetration on hydraulic head distribution for three types of aquifer tests.
Current state in adsorption from multicomponent solutions of nonelectrolytes on solids
International Nuclear Information System (INIS)
Borowko, M.; Jaroniec, M.
1983-01-01
This paper surveys the research carried out on the adsorption from multicomponent liquid mixtures of nonelectrolytes on solids with emphasis on the work performed by the authors. The consistent theoretical treatment of adsorption from concentrated and dilute multicomponent solutions and its application to the liquid adsorption chromatography with the mixed mobile phase are presented. This treatment involved nonideality of the bulk and surface phases, energetic heterogeneity of the adsorbent surface and it may be extended to multilayer adsorption from solutions. The multicomponent liquid/solid adsorption systems, studied experimentally, are reviewed. Many of them have been examined by means of the equations derived for liquid adsorption on heterogeneous surfaces. These studies are summarized in this paper. Moreover, the model studies illustrating the influence of solution nonideality and adsorbent heterogeneity on the excess adsorption isotherms and the distribution coefficient are discussed. (orig.)
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
A Solution Space for a System of Null-State Partial Differential Equations: Part 2
Flores, Steven M.; Kleban, Peter
2015-01-01
This article is the second of four that completely and rigorously characterize a solution space for a homogeneous system of 2 N + 3 linear partial differential equations in 2 N variables that arises in conformal field theory (CFT) and multiple Schramm-Löwner evolution (SLE). The system comprises 2 N null-state equations and three conformal Ward identities which govern CFT correlation functions of 2 N one-leg boundary operators. In the first article (Flores and Kleban, Commun Math Phys, arXiv:1212.2301, 2012), we use methods of analysis and linear algebra to prove that dim , with C N the Nth Catalan number. The analysis of that article is complete except for the proof of a lemma that it invokes. The purpose of this article is to provide that proof. The lemma states that if every interval among ( x 2, x 3), ( x 3, x 4),…,( x 2 N-1, x 2 N ) is a two-leg interval of (defined in Flores and Kleban, Commun Math Phys, arXiv:1212.2301, 2012), then F vanishes. Proving this lemma by contradiction, we show that the existence of such a nonzero function implies the existence of a non-vanishing CFT two-point function involving primary operators with different conformal weights, an impossibility. This proof (which is rigorous in spite of our occasional reference to CFT) involves two different types of estimates, those that give the asymptotic behavior of F as the length of one interval vanishes, and those that give this behavior as the lengths of two intervals vanish simultaneously. We derive these estimates by using Green functions to rewrite certain null-state PDEs as integral equations, combining other null-state PDEs to obtain Schauder interior estimates, and then repeatedly integrating the integral equations with these estimates until we obtain optimal bounds. Estimates in which two interval lengths vanish simultaneously divide into two cases: two adjacent intervals and two non-adjacent intervals. The analysis of the latter case is similar to that for one vanishing
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.
phase formation and thermal stability of fcc (fluorite) Ce1-xTbxO2-d solid solutions
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
Ionic thermocurrents and ionic conductivity of solid solutions of SrF2 and YbF3
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
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)
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.)
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
Non-linear partial differential equations an algebraic view of generalized solutions
Rosinger, Elemer E
1990-01-01
A massive transition of interest from solving linear partial differential equations to solving nonlinear ones has taken place during the last two or three decades. The availability of better computers has often made numerical experimentations progress faster than the theoretical understanding of nonlinear partial differential equations. The three most important nonlinear phenomena observed so far both experimentally and numerically, and studied theoretically in connection with such equations have been the solitons, shock waves and turbulence or chaotical processes. In many ways, these phenomen
A fluorescent chemosensor for Zn(II). Exciplex formation in solution and the solid state.
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.
International Nuclear Information System (INIS)
Dresner, L.
1990-07-01
This report deals with the asymptotic behavior of certain solutions of partial differential equations in one dependent and two independent variables (call them c, z, and t, respectively). The partial differential equations are invariant to one-parameter families of one-parameter affine groups of the form: c' = λ α c, t' = λ β t, z' = λz, where λ is the group parameter that labels the individual transformations and α and β are parameters that label groups of the family. The parameters α and β are connected by a linear relation, Mα + Nβ = L, where M, N, and L are numbers determined by the structure of the partial differential equation. It is shown that when L/M and N/M are L/M t -N/M for large z or small t. Some practical applications of this result are discussed. 8 refs
Zhang, Kejiang; Achari, Gopal; Li, Hua
2009-11-03
Traditionally, uncertainty in parameters are represented as probabilistic distributions and incorporated into groundwater flow and contaminant transport models. With the advent of newer uncertainty theories, it is now understood that stochastic methods cannot properly represent non random uncertainties. In the groundwater flow and contaminant transport equations, uncertainty in some parameters may be random, whereas those of others may be non random. The objective of this paper is to develop a fuzzy-stochastic partial differential equation (FSPDE) model to simulate conditions where both random and non random uncertainties are involved in groundwater flow and solute transport. Three potential solution techniques namely, (a) transforming a probability distribution to a possibility distribution (Method I) then a FSPDE becomes a fuzzy partial differential equation (FPDE), (b) transforming a possibility distribution to a probability distribution (Method II) and then a FSPDE becomes a stochastic partial differential equation (SPDE), and (c) the combination of Monte Carlo methods and FPDE solution techniques (Method III) are proposed and compared. The effects of these three methods on the predictive results are investigated by using two case studies. The results show that the predictions obtained from Method II is a specific case of that got from Method I. When an exact probabilistic result is needed, Method II is suggested. As the loss or gain of information during a probability-possibility (or vice versa) transformation cannot be quantified, their influences on the predictive results is not known. Thus, Method III should probably be preferred for risk assessments.
Directory of Open Access Journals (Sweden)
Dibyangana Raul
2014-01-01
Full Text Available Amylase is an enzyme that catalyzes the breakdown of starch into sugars and plays a pivotal role in a variety of areas like use as digestives, for the production of ethanol and high fructose corn syrup, detergents, desiring of textiles, modified starches, hydrolysis of oil-field drilling fluids, and paper recycling. In the present work, solid state fermentation (SSF for α-amylase production has been used in lieu of submerged fermentation (SmF due to its simple technique, low capital investment, lower levels of catabolite repression, and better product recovery. Bacillus subtilis has been well known as producer of alpha amylase and was tested using solid state fermentation for 48 hours at 37°C with wheat bran as substrate. Comparison between different fermentation hours demonstrated high yield of alpha amylase after 48 hours. This alpha amylase has optimum pH and temperature at 7.1 and 40°C, respectively. With the goal to purify alpha amylase, 30–70% (NH42SO4 cut concentrated the amylase activity threefold with respect to crude fermented extract. This was verified in quantitative DNS assay method as well as in zymogram gel profile. The exact molecular weight of the amylase is yet to be determined with the aid of other protein purification techniques.
Giant asymmetry of separation and homogenization processes in solid 3He-4He solutions
International Nuclear Information System (INIS)
Grigor'ev, V.N.; Majdanov, V.A.; Penzev, A.A.; Polev, A.V.; Rubets, S.P.; Rudavskij, Eh.Ya.; Rybalko, A.S.; Syrnikov, E.V.
2005-01-01
The kinetics of the processes of separation and homogenization of solid 3 He- 4 He solutions is compared by using the precision barometry. The experiments were made with the initial specimens of three types: weak 3 He- 4 He and 4 He- 3 He solutions and concentrated 3 He- 4 He ones. It is found that the homogenization rate at the initial stage may be more than 500 times higher that the rate of separation. This is the case for all types of the solutions studied. The appreciable rate of phase separation in the concentrated solutions where, according to the modern concepts, impurity atoms in quantum crystals should be localized, suggests that in such conditions there is a new unknown mechanism of mass-transfer, while the fast homogenization points to a nondiffusion nature of the process
The crystallization of a solid solution in a solvent and the stability of a growth interface
International Nuclear Information System (INIS)
Malmejac, Yves
1971-03-01
The potential uses of germanium-silicon alloys as thermoelectric generators in hitherto unexploited temperature ranges initiated the present study. Many delicate problems are encountered in the classical methods of preparation. An original technique was sought for crystallization in a metallic solvent. The thermodynamic equilibria between the various phases of the ternary System used were studied in order to justify the method used. The conditions (temperature and composition) were determined in which the cooling of a ternary liquid mixture induces the precipitation of a binary solid solution with the desired composition. If large crystals are to be obtained from the solid solution, metallic solvent precipitation must be replaced by a mono-directional solvent crystallization. The combined effect of a certain number of simple physical phenomena on the stability of a crystal liquid interface was studied: the morphological stability of the crystal growth interface is the first step towards obtaining perfect crystals. (author) [fr
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
International Nuclear Information System (INIS)
Zhang, Yanwen; Wang, Lumin; Caro, Alfredo; Weber, William J.; Univ. of Tennessee, Knoxville, TN
2015-01-01
A long-standing objective in materials research is to understand how energy is dissipated in both the electronic and atomic subsystems in irradiated materials, and how related non-equilibrium processes may affect defect dynamics and microstructure evolution. Here we show that alloy complexity in concentrated solid solution alloys having both an increasing number of principal elements and altered concentrations of specific elements can lead to substantial reduction in the electron mean free path and thermal conductivity, which has a significant impact on energy dissipation and consequentially on defect evolution during ion irradiation. Enhanced radiation resistance with increasing complexity from pure nickel to binary and to more complex quaternary solid solutions is observed under ion irradiation up to an average damage level of 1 displacement per atom. Understanding how materials properties can be tailored by alloy complexity and their influence on defect dynamics may pave the way for new principles for the design of radiation tolerant structural alloys
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
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
Wei, Ran; Sun, Huan; Chen, Chen; Tao, Juan; Li, Fushan
2018-03-01
Fe-Co-Ni-Si-B high entropy amorphous alloys composites (HEAACs), which containing high entropy solid solution phase in amorphous matrix, show good soft magnetic properties and bending ductility even in optimal annealed state, were successfully developed by melt spinning method. The crystallization phase of the HEAACs is solid solution phase with body centered cubic (BCC) structure instead of brittle intermetallic phase. In addition, the BCC phase can transformed into face centered cubic (FCC) phase with temperature rise. Accordingly, Fe-Co-Ni-Si-B high entropy alloys (HEAs) with FCC structure and a small amount of BCC phase was prepared by copper mold casting method. The HEAs exhibit high yield strength (about 1200 MPa) and good plastic strain (about 18%). Meanwhile, soft magnetic characteristics of the HEAs are largely reserved from HEAACs. This work provides a new strategy to overcome the annealing induced brittleness of amorphous alloys and design new advanced materials with excellent comprehensive properties.
Directory of Open Access Journals (Sweden)
Fukang Yin
2013-01-01
Full Text Available A numerical method is presented to obtain the approximate solutions of the fractional partial differential equations (FPDEs. The basic idea of this method is to achieve the approximate solutions in a generalized expansion form of two-dimensional fractional-order Legendre functions (2D-FLFs. The operational matrices of integration and derivative for 2D-FLFs are first derived. Then, by these matrices, a system of algebraic equations is obtained from FPDEs. Hence, by solving this system, the unknown 2D-FLFs coefficients can be computed. Three examples are discussed to demonstrate the validity and applicability of the proposed method.
Microstructure and Mechanical Strengths of Metastable FCC Solid Solutions in Al-Ce-Fe System
A., Inoue; H., Yamaguchi; M., Kikuchi; T., Masumoto; Institute for Materials Research; Institute for Materials Research; Institute for Materials Research; Institute for Materials Research
1990-01-01
A metastable fcc solid solution (SS) with high mechanical strengths and good bending ductility was found to be formed in rapidly solidified Al-Ce-Fe alloys containing the solute elements below about 6 at%. The SS consists of equiaxed grains with a size of about 2μm and contains a high density of internal defects. The highest hardness (H_v) and tensile fracture strengtn (σ_f) are 440 and 860 MPa in the as-quenched state and remain almost unchanged up to about 600 K for 1 h, though fine compoun...
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
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
International Nuclear Information System (INIS)
Abbasov, Sh.M.
2002-01-01
Full Text: In the present work the tensometrical properties of Ge1-xSix solid solution monocrystal contended of up to 15 at. % Si were investigated. The radiation-proof strain gauges of researched crystals were made. For this purpose the site was cutted out from a sample, perpendicularly or in parallel of a crystal axes. After polishing the samples had thickness of 30-40 microns, and length of 2 mm
First-principles investigations of solid solution strengthening in Al alloys
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...
Studying the Super-cooled Solid Solution Breakdown of V-1341 Aluminum Alloy
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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.
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.)
Energy Technology Data Exchange (ETDEWEB)
Azzoni, C.B. [Istituto Nazionale di Fisica della Materia, Dipartimento di Fisica ' Alessandro Volta' , Universita di Pavia, Pavia (Italy); Paleari, A. [Istituto Nazionale di Fisica della Materia, Dipartimento di Fisica, Universita di Milano, Milan (Italy); Massarotti, V.; Capsoni, D. [Dipartimento di Chimica-Fisica, Universita di Pavia, Pavia (Italy)
1996-09-23
EPR data of ordered solid solutions of lithium nickel oxides are reported as a function of the lithium content. The features of the signal and the EPR centre density are analysed by a model of dynamical trapping of holes in [(Ni{sup 2+}-O-Ni{sup 2+})-h{sup +}] complexes. The possible origin of the interactions responsible for the magnetic ordering and some features of the transport properties are also discussed. (author)
Contribution to the study of the structure of silver krypton solid solutions
International Nuclear Information System (INIS)
Levy, V.; Tullairet, J.; Delaplace, J.; Antolin-Baudier, J.; Adda, Y.
1964-01-01
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) [fr
International Nuclear Information System (INIS)
Orlov, A.N.; Trushin, Yu.V.
1988-01-01
An attempt was made to make allowance for the role of binary and ternary interstitials in the kinetics of radiation point defects both in the presence and in the absence of coherent preseparation. It is shown that in solid solutions, decomposing under irradiation, recombination with binary and ternary interstitials proceeds more quickly than directly, and this difference is more pronounced (from 2 up to 20 time growth) due to defect flow for preseparation at the stage of coherent preseparation formation
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
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
Photophysical processes study for poly (P-substituted styrenes) in solid films and in solutions
International Nuclear Information System (INIS)
Al-Hakeem, I.A.
1985-01-01
In this work, the absorption and emission spectra of poly (P-NN dimethyl amino styrene), poly (P-Fluoro Styrene), poly (P-CH2OCH3 styrene), poly (P-Methyl (styrene), poly(P-Tertiary butyl styrene) have been studied in solid films and solutions. The effect of added dimethylterph-thalate as a quencher to the fluorescence emission of the polymers used in this work were studied.(5 tabs., 39 figs., 60 refs.)
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
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.
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
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.
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.
A Method for Generating Approximate Similarity Solutions of Nonlinear Partial Differential Equations
Directory of Open Access Journals (Sweden)
Mazhar Iqbal
2014-01-01
Full Text Available Standard application of similarity method to find solutions of PDEs mostly results in reduction to ODEs which are not easily integrable in terms of elementary or tabulated functions. Such situations usually demand solving reduced ODEs numerically. However, there are no systematic procedures available to utilize these numerical solutions of reduced ODE to obtain the solution of original PDE. A practical and tractable approach is proposed to deal with such situations and is applied to obtain approximate similarity solutions to different cases of an initial-boundary value problem of unsteady gas flow through a semi-infinite porous medium.
The Multi-Wave Method for Exact Solutions of Nonlinear Partial Differential Equations
Directory of Open Access Journals (Sweden)
Yusuf Pandir
2018-02-01
Full Text Available In this research, we use the multi-wave method to obtain new exact solutions for generalized forms of 5th order KdV equation and fth order KdV (fKdV equation with power law nonlinearity. Computations are performed with the help of the mathematics software Mathematica. Then, periodic wave solutions, bright soliton solutions and rational function solutions with free parameters are obtained by this approach. It is shown that this method is very useful and effective.
Directory of Open Access Journals (Sweden)
Shaheed N. Huseen
2013-01-01
Full Text Available A modified q-homotopy analysis method (mq-HAM was proposed for solving nth-order nonlinear differential equations. This method improves the convergence of the series solution in the nHAM which was proposed in (see Hassan and El-Tawil 2011, 2012. The proposed method provides an approximate solution by rewriting the nth-order nonlinear differential equation in the form of n first-order differential equations. The solution of these n differential equations is obtained as a power series solution. This scheme is tested on two nonlinear exactly solvable differential equations. The results demonstrate the reliability and efficiency of the algorithm developed.
International Nuclear Information System (INIS)
Dorhout, P.K.; Rosenthal, G.L.; Ellis, A.B.
1988-01-01
Hydrogen uranyl phosphate, HUO 2 PO 4 x 4H 2 O (HUP), and hydrogen uranyl arsenate, HUO 2 AsO 4 x 4H 2 O (HUAs), form solid solutions of composition HUO 2 (PO 4 ) 1-x (AsO 4 )x (HUPAs), representing a family of lamellar, luminescent solids that can serve as hosts for intercalation chemistry. The solids are prepared by aqueous precipitation reactions from uranyl nitrate and mixtures of phosphoric and arsenic acids; thermogravimetric analysis indicates that the phases are tetrahydrates, like HUP and HUAs. Powder x-ray diffraction data reveal the HUPAs solids to be single phases whose lattice constants increase with X, in rough accord with Vegard's law Spectral shifts observed for the HUPAs samples. Emission from the solids is efficient (quantum yields of ∼ 0.2) and long-lived (lifetimes of ∼ 150 μs), although the measured values are uniformly smaller than those of HUP and HUAs; unimolecular radiative and nonradiative rate constants for excited-state decay of ∼ 1500 and 5000 s -1 , respectively, have been calculated for the compounds. 18 refs., 5 figs., 2 tabs
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.
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
Fast Time and Space Parallel Algorithms for Solution of Parabolic Partial Differential Equations
Fijany, Amir
1993-01-01
In this paper, fast time- and Space -Parallel agorithms for solution of linear parabolic PDEs are developed. It is shown that the seemingly strictly serial iterations of the time-stepping procedure for solution of the problem can be completed decoupled.
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
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
Transport properties of dilute α -Fe (X ) solid solutions (X = C, N, O)
Schuler, Thomas; Nastar, Maylise
2016-06-01
We extend the self-consistent mean field (SCMF) method to the calculation of the Onsager matrix of Fe-based interstitial solid solutions. Both interstitial jumps and substitutional atom-vacancy exchanges are accounted for. A general procedure is introduced to split the Onsager matrix of a dilute solid solution into intrinsic cluster Onsager matrices, and extract from them flux-coupling ratios, mobilities, and association-dissociation rates for each cluster. The formalism is applied to vacancy-interstitial solute pairs in α -Fe (V X pairs, X = C, N, O), with ab initio based thermodynamic and kinetic parameters. Convergence of the cluster mobility contribution gives a controlled estimation of the cluster definition distance, taking into account both its thermodynamic and kinetic properties. Then, the flux-coupling behavior of each V X pair is discussed, and qualitative understanding is achieved from the comparison between various contributions to the Onsager matrix. Also, the effect of low-activation energy second-nearest-neighbor interstitial solute jumps around a vacancy on these results is addressed.
Yang, Xiang-Jun; Wang, Shi-Xiong; Zou, An-Qin; Chen, Jing; Guo, Hong
2014-02-01
Trialkyphosphine oxides (TRPO) was successfully used for the impregnation of D3520 resin to prepare an extractant-impregnated resin (EIR). Solid extraction of Au(I) from alkaline cyanide solution was studied using this extractant-impregnated resin (EIR), with addition of cetyltrimethylammonium bromide (CTMAB), directly into the aurous aqueous phase in advance. The mechanism of solid extraction was further investigated by means of FTIR, XPS and SEM. The column separation studies have shown that cationic surfactant CTMAB played a key role in the solid phase extraction, and the resin containing TRPO were effective for the extraction of gold when the molar ratio of CTMAB: Au( I ) reached 1:1. FTIR spectroscopy of gold loaded EIR showed that the frequency of C[triple bond]N stretching vibration was at 2144 cm(-1), and the frequency of P=O stretching vibration shifted to lower frequency from 1153 to 1150 cm(-1). The XPS spectrum of N(1s), Au(4f7/2) and Au(4f5/2) sugges- ted that the coordination environment of gold did not change before and after extraction, and gold was still as the form of Au (CN)2(-) anion exiting in the loaded resin; O(1s) spectrum showed that the chemically combined water significantly increased after solid extraction from 30.74% to 42.34%; Comparing to the P(2p) spectrum before and after extraction, the binding energy increased from 132. 15 to 132. 45 eV, indicating there maybe existing hydrogen-bond interaction between P=O and water molecule, such as P=O...H-O-H. The above results obtained established that in the solid extraction process, the hydrophobic ion association [CTMA+ x Au(CN)] diffused from the bulk solution into the pores of the EIR, and then be solvated by TRPO adsorbed in the pores through hydrogen bonding bridged by the water molecules.
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.
Valence states of cobalt and crystal structure peculiarities of solid solution YBa2Cu3-xCoxO6+σ
International Nuclear Information System (INIS)
Voronin, V.I.; Goshchinskij, B.N.; Mitberg, Eh.B.; Leonidov, I.A.; Kozhevnikov, V.L.
2000-01-01
Crystal structure of solid solution YBa 2 Cu 3-x Co x O 6+σ , where x = 0.2, 0.4, 0.6 and 0.8, is studied by the method of powder neutron diffraction. Charge states of the cation are calculated using the interatomic distances obtained. It is shown that cobalt in Cu1 position has valency 3 + and octahedral coordination at x = 0.2 and 0.4. Increase in doping degree involves both transition of a portion of cobalt ions in the positions mentioned to the state with valence 4 + and tetrahedral coordination and partial substitution of copper in Cu2 position [ru
Operational method of solution of linear non-integer ordinary and partial differential equations.
Zhukovsky, K V
2016-01-01
We propose operational method with recourse to generalized forms of orthogonal polynomials for solution of a variety of differential equations of mathematical physics. Operational definitions of generalized families of orthogonal polynomials are used in this context. Integral transforms and the operational exponent together with some special functions are also employed in the solutions. The examples of solution of physical problems, related to such problems as the heat propagation in various models, evolutional processes, Black-Scholes-like equations etc. are demonstrated by the operational technique.
Decay property of regularity-loss type for solutions in elastic solids with voids
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.
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
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.
International Nuclear Information System (INIS)
Quang A, Dang; Hai, Truong Ha
2014-01-01
Very recently in the work S imple Iterative Method for Solving Problems for Plates with Partial Internal Supports, Journal of Engineering Mathematics, DOI: 10.1007/s10665-013-9652-7 (in press) , we proposed a numerical method for solving some problems of plates on one and two line partial internal supports (LPIS). In the essence they are problems with strongly mixed boundary conditions for biharmonic equation. Using this method we reduced the problems to a sequence of boundary value problems for the Poisson equation with weakly mixed boundary conditions, which are easily solved numerically. The advantages of the method over other ones were shown. In this paper we apply the method to plates on internal supports of more complicated configurations. Namely, we consider the case of three LPIS and the case of the cross support. The convergence of the method is established theoretically and its efficiency is confirmed on numerical experiments
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)
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
A partial solution for Feynman's problem: A new derivation of the Weyl equation
Directory of Open Access Journals (Sweden)
Atsushi Inoue
2000-07-01
Full Text Available Associating classical mechanics to a system of partial differential equations, we give a procedure for Feynman-type quantization of a "Schrodinger-type equation with spin." Mathematically, we construct a "good parametrix" for the Weyl equation with an external electromagnetic field. Main ingredients are (i a new interpretation of the matrix structure using superanalysis and (ii another interpretation of the method of characteristics as a quantization procedure of Feynman type.
International Nuclear Information System (INIS)
Fischer, E.
1977-01-01
Various families of exact solutions to the Einstein and Einstein--Maxwell field equations of general relativity are treated for situations of sufficient symmetry that only two independent variables arise. The mathematical problem then reduces to consideration of sets of two coupled nonlinear differential equations. The physical situations in which such equations arise include: the external gravitational field of an axisymmetric, uncharged steadily rotating body, cylindrical gravitational waves with two degrees of freedom, colliding plane gravitational waves, the external gravitational and electromagnetic fields of a static, charged axisymmetric body, and colliding plane electromagnetic and gravitational waves. Through the introduction of suitable potentials and coordinate transformations, a formalism is presented which treats all these problems simultaneously. These transformations and potentials may be used to generate new solutions to the Einstein--Maxwell equations from solutions to the vacuum Einstein equations, and vice-versa. The calculus of differential forms is used as a tool for generation of similarity solutions and generalized similarity solutions. It is further used to find the invariance group of the equations; this in turn leads to various finite transformations that give new, physically distinct solutions from old. Some of the above results are then generalized to the case of three independent variables
Energy Technology Data Exchange (ETDEWEB)
Kong, Bin, E-mail: kongbin@buaa.edu.cn; Jia, Lina, E-mail: jialina@buaa.edu.cn; Su, Linfen, E-mail: sulinfen@mse.buaa.edu.cn; Guan, Kai, E-mail: guankai@mse.buaa.edu.cn; Weng, Junfei, E-mail: wengjf@mse.buaa.edu.cn; Zhang, Hu, E-mail: zhanghu@buaa.edu.cn
2015-07-15
Controlling the elements content in the niobium solid solution (Nb{sub SS}) is significant for the better comprehensive performance of Nb-silicide-based alloys. In this paper, the effects of minor Si on the microstructures and room temperature fracture toughness of Nb–(0/0.5/1/2)Si–27.63Ti–12.92Cr–2.07Al–1.12Hf (at%, unless stated otherwise) solid solution alloys were investigated. The alloys were processed by vacuum arc-casting (AC), and then heat treated (HT) at 1425 °C for 10 h. In HT alloys, Nb{sub SS} grains are refined gradually with the increase of Si content. Meanwhile, the volume fraction of Cr{sub 2}Nb and silicides phases precipitates increases. The fracture toughness of HT alloys decreases at first but then increases in the range of 0 to 2% Si, because it is a combinatorial process of positive and negative effects caused by the addition of Si. The refinement of Nb{sub SS} grains displays positive effect on fracture toughness, while the increase of solid solubility of Si in Nb{sub SS} and brittle Cr{sub 2}Nb and Nb-silicides precipitate phases display negative effect.
International Nuclear Information System (INIS)
Radonjic, L.; Todorovic, M.; Miladinovic, J.
2005-01-01
Transparent, nanostructured glass ceramics based on ferroelectric solid solutions of the type Na 1-x Li x NbO 3 (in very narrow composition regions for x = 0.12 and 0.93) and LiNb 1-y Ta y O 3 (y = 0.5 unlimited solid solubility), can be obtained by controlled crystallization of glass. The parent glass samples were prepared by conventional melt-quenching technique. Heat-treatment of the parent glasses was performed at the various temperatures, for the same time. The glass structure evolution during the controlled crystallization was examined by FT-IR spectroscopy analysis. Crystalline phases were identified by X-ray diffraction analysis and SEM was used for microstructure characterization. Densities of the crystallized glasses were measured by Archimedean principle. The capacitance and dielectric loss tangent were measured at a frequency of 1 kHz, at the room temperature. It was found that in the all investigated systems crystallize solid solutions Na 1-x Li x NbO 3 and LiNb 1-y Ta y O 3 in the glassy matrix, have crystal size on nanoscale (less than 100 nm), which is one of requirements to get a transparent glass ceramic that could be a good ferroelectric material regarding to the measured properties
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.
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
Energy Technology Data Exchange (ETDEWEB)
Du Fou De Kerdaniel, E
2007-12-15
In the field of the radwaste storage in underground repository, several matrices were considered as promising ceramics for the specific immobilization of actinides. Two of them, britholites and monazite/ brabantite solid solution, have been considered during this work. In order to examine the dissolution mechanisms occurring at the solid liquid interface, several leaching experiments have been conducted on (Ln{sup III}PO{sub 4} ), brabantite (Ca{sup II}An{sup IV}(PO{sub 4}){sub 2}: An = Th, U) and britholites (Ca{sub 9}Nd{sub 0.5}An{sub 0.5}{sup IV} (PO{sub 4}){sub 4.5}(SiO{sub 4}){sub 1.5}F{sub 2}: An = Th, U). Some steady experiments, performed in under saturation conditions for various pH and temperature conditions allowed to evaluate the long term behaviour of such matrices through their chemical durability. On the contrary, the thermodynamic equilibria were examined through the leaching experiments performed near the saturation conditions. By the way, various secondary phases, precipitated onto the surface of altered samples have been identified and characterized. Among them, the (Nd, Ca, Th) - rhabdophane, novelly prepared in over- saturation experiments for a thorium weight loading lower than 11 % appeared to be metastable. Indeed, it turns into TPHPH (Th{sub 2}(PO{sub 4}){sub 2}HPO{sub 4}.H{sub 2}O) and Nd - rhabdophane (NdPO{sub 4}.1/2H{sub 2}O) when increasing leaching time. (author)
An ordered metallic glass solid solution phase that grows from the melt like a crystal
International Nuclear Information System (INIS)
Chapman, Karena W.; Chupas, Peter J.; Long, Gabrielle G.; Bendersky, Leonid A.; Levine, Lyle E.; Mompiou, Frédéric; Stalick, Judith K.; Cahn, John W.
2014-01-01
We report structural studies of an Al–Fe–Si glassy solid that is a solid solution phase in the classical thermodynamic sense. We demonstrate that it is neither a frozen melt nor nanocrystalline. The glass has a well-defined solubility limit and rejects Al during formation from the melt. The pair distribution function of the glass reveals chemical ordering out to at least 12 Å that resembles the ordering within a stable crystalline intermetallic phase of neighboring composition. Under isothermal annealing at 305 °C the glass first rejects Al, then persists for approximately 1 h with no detectable change in structure, and finally is transformed by a first-order phase transition to a crystalline phase with a structure that is different from that within the glass. It is possible that this remarkable glass phase has a fully ordered atomic structure that nevertheless possesses no long-range translational symmetry and is isotropic
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.
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.
Synthesis and properties of γ-Ga2O3-Al2O3 solid solutions
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.
International Nuclear Information System (INIS)
Hatada, Motoyoshi; Fujita, Iwao; Korekawa, Kei-ichi.
1994-10-01
Studies have been carried out on the radiation chemical formation of palladium fine particles in argon saturated aqueous solutions of sodium chloropalladate without organic stabilizer. The solutions were irradiated with gamma-rays from a cobalt gamma-ray source and the irradiated solutions were subjected to the dynamic light scattering analysis for the particle diameter measurements, and to the UV-visible optical absorption spectroscopy for the measurements of turbidity (absorption at 700 nm) and remaining chloropalladate ion concentrations in the solution. In the solution of pH = 1.95 by HCl, the turbidity increased after the irradiation and then decreased with time. The concentration of remaining palladate ion in the solution decreased by the irradiation, but it gradually increased with time after the irradiation. These phenomena were qualitatively explained by the reaction scheme in that a precursor to the solid particles still exists in the solution after the irradiation was terminated, and that intermediates including the precursor reacted with chloride ion to re-form chloropalladate ions. The average diameter of the particles after the irradiation was ca. 20 nm and it increased with time to 40 nm at 2.75 kGy, and to 80 nm at 8.25 kGy absorption of radiation. The solution of pH = 0.65 by HCl was found to give lower yields of particles than those observed for the solution of pH = 1.95, and to give the particles of diameters about 150-200 nm. In the solution containing HClO 4 instead of HCl, palladium particles were also formed by the irradiation, whereas no backward reaction after the irradiation was observed due to the low concentration of chloride ion in the solution. The average diameter of the particles after the irradiation was about 300 nm and increased with time after the irradiation to a final values which was found to depend on pH of the solution and dose. (author)
International Nuclear Information System (INIS)
Cui, Yajuan; Fang, Ruimei; Shang, Hongyan; Shi, Zhonghua; Gong, Maochu; Chen, Yaoqiang
2015-01-01
Highlights: • The crystallite size of precipitate increases as the precipitation temperature rises. • The stack of large crystallite can form nanoparticles with big pore size. • Big pore sizes are advantageous to improve the thermal stability. • Phase segregation is restricted in CZ solid solution precipitated at 70 °C. • The reducibility and OSC of the solid solution precipitated at 70 °C are improved. - Abstract: The ceria–zirconia composites (CZ) with a Ce/Zr mass ratio of 1/1 were synthesized by a back-titration method, in which the influence of precipitation temperature on the properties of ceria–zirconia precipitates was investigated. The resulting precipitation and mixed oxides at different precipitation temperatures were then characterized by a range of techniques, including textural properties, X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), H 2 -temperature programmed reduction (H 2 -TPR) as well as oxygen storage capacity (OSC) measurement. The results revealed that ceria–zirconia composites were formed as solid solution and such structure is favored of thermostability and texture properties. In particular, the composite CZ-70 synthesized at 70 °C exhibited prominent thermostability with a surface area of 32 m 2 /g as well as a pore volume of 0.15 cc/g after aging treatment at 1000 °C for 5 h. And this was found to be associated with the wider pore size distribution which maybe owed to the formation of large crystal at the primary stage of precipitation. Additionally, the composite CZ-70 showed excellent reduction property and OSC benefiting from stable texture and structure
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
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)
Directory of Open Access Journals (Sweden)
A. A. Hemeda
2013-01-01
Full Text Available An extension of the so-called new iterative method (NIM has been used to handle linear and nonlinear fractional partial differential equations. The main property of the method lies in its flexibility and ability to solve nonlinear equations accurately and conveniently. Therefore, a general framework of the NIM is presented for analytical treatment of fractional partial differential equations in fluid mechanics. The fractional derivatives are described in the Caputo sense. Numerical illustrations that include the fractional wave equation, fractional Burgers equation, fractional KdV equation, fractional Klein-Gordon equation, and fractional Boussinesq-like equation are investigated to show the pertinent features of the technique. Comparison of the results obtained by the NIM with those obtained by both Adomian decomposition method (ADM and the variational iteration method (VIM reveals that the NIM is very effective and convenient. The basic idea described in this paper is expected to be further employed to solve other similar linear and nonlinear problems in fractional calculus.
International Nuclear Information System (INIS)
Danilkin, S.A.
1978-01-01
The frequency spectra calculation of disordered solid interstitial solutions of a vanadium-oxygen system for oxygen concentration of 5.9% and 15.8% (V 16 O and V 16 O 3 ) is carried out. The axially-symmetric model of crystal lattice dinamics with consideration of vanadium-oxygen and vanadium-vanadium interactions up to the second coordination sphere is used. On the whole, the obtained spectra are in qualitative agreement with experiment and reflect correctly all the changes in frequency spectra of pure vanadium on doping with oxygen
The role of solid-solution strengthening in the development of alloys for HTR applications
International Nuclear Information System (INIS)
Dean, A.V.
1978-09-01
In this paper the fundamental factors (lattice distortion, stacking fault energy and diffusion rates) which contribute to solid-solution strengthening are examined and used as a basis for indicating the composition of alloys likely to posses the highest strength at elevated temperatures. Alloys based on Ni-Cr-W-Mo should possess the best properties but alloys based on Ni-Cr-Nb-Ti are also recommended for further study. The effect of alloy composition on corrosion resistance has been excluded from this examination but it should be possible to adjust alloy composition in order to optimise corrosion resistance. (orig./IHOE) [de
International Nuclear Information System (INIS)
Agamaliyev, Z.A.; Tahirov, V.I.; Hasanov, Z.Y.; Quliyev, A.F.
2007-01-01
A binary solid solution single crystal growth method has been worked out. Cylinder feeding alloy with complex content distribution and truncated cone crucible are used. Second component distribution coefficient is more than unit. Content distribution along grown crystal is found by solving continuity equation. After reaching dynamic equilibrium state second component concentration in grown crystal is saturated the value of which is less than the average ona in the feeding alloy. Using the method Ge-Si perfect single crystals has been grown. Calculation method of melt surface displacement velocity has been offered as well
Formation of solid solutions on the boundary of zinc oxidezinc telluride heterojunction
International Nuclear Information System (INIS)
Tsurkan, A.E.; Buzhor, L.V.
1987-01-01
Distribution of ZnO x Te 1-x alloy composition on the interface of zinc oxide-zinc telluride heterojunction depending on the production conditions is investigated. A regularity in the formation of an extended area with constant alloy composition is detected. The regularity is explained by the fact that electric Peltier field conditioned by contact of two heterogeneous semiconductors participates in the solid solution formation process. Peltier field levels off the composition at the end length section. So, a possibility of creating a section with the assigned minor thickness alloy constant composition controlled in the interface of heterojunction occurs
The X-ray electronic spectra of TiC-NbC solid solution
International Nuclear Information System (INIS)
Cherkashenko, V.M.; Ezhov, A.V.; Nazarova, S.Z.; Kurmaev, Eh.Z.; Nojmann, M.
2001-01-01
X-ray photoelectronic spectra of inner levels and valency lands in TiC-NbC solid solutions were studied. Results of combining TiL α -, NbL β2.15 -, CK α - X-ray emission spectra and photoelectronic spectra of valency bands in one energy scale in reference to the Fermi level were analyzed. It is shown that a change in crystal lattice parameters, as well as charge redistribution between titanium and niobium atoms, produce a strong effect on electronic structure formation in the mixed carbides mentioned [ru
DEFF Research Database (Denmark)
Bialy, Agata; Jensen, Peter Bjerre; Blanchard, Didier
2015-01-01
with spray drying and in situ thermogravimetric and structural characterization, we synthesize a range of new, stable barium-strontium chloride solid solutions with superior ammonia storage densities. By tuning the barium/strontium ratio, different crystallographic phases and compositions can be obtained...... with different ammonia ab- and desorption properties. In particular it is shown, that in the molar range of 35–50% barium and 65–50% strontium, stable materials can be produced with a practically usable ammonia density (both volumetric and gravimetric) that is higher than any of the pure metal halides...
Local structure in the disordered solid solution of cis- and trans-perinones
DEFF Research Database (Denmark)
Teteruk, Jaroslav L.; Glinnemann, Juergen; Heyse, Winfried
2016-01-01
preferred local arrangements, ordering lengths, and probabilities for the arrangement of neighbouring molecules. The superposition of the atomic positions of all energetically favourable calculated models corresponds well with the experimentally determined crystal structures, explaining not only the atomic....... The crystal structure of the solid solution was determined by single-crystal X-ray analysis. Extensive lattice-energy minimizations with force-field and DFT-D methods were carried out on combinatorially complete sets of ordered models. For the disordered systems, local structures were calculated, including...
Photoluminescence study in solid solutions of CdMgMnTe semimagnetic semiconductors
International Nuclear Information System (INIS)
Kusraev, Yu.G.; Averkieva, G.K.
1993-01-01
Luminescence and resonant Raman scattering in quaternary solid solutions of CdMgMnTe semimagnetic semiconductors are investigated. It is shown that the intensity and position of the luminescence band, conditioned by the 4 T 1 --> 6 A 1 optical transitions in the Mn d-shell, depend on the local crystal environment. Temperature variations of the photoluminescence spectra are interpreted on the base of a model of electron excitation energy transport from Mn 2+ to different recombination centers. In the resonant Raman scattering spectrum were observed three longitudinal vibrational modes with energies near to phonon energies of corresponding binary compounds
International Nuclear Information System (INIS)
Hedwig, Gavin R.; Jameson, Geoffrey B.; Hoiland, Harald
2011-01-01
Highlights: → Solution densities and sound speeds were measured for aqueous solutions of thymidine. → Partial molar volumetric properties at infinite dilution and T = 298.15 K were derived. → The partial molar isentropic and isothermal compressions are of opposite signs. → The partial molar heat capacity for thymidine at infinite dilution was determined. - Abstract: Solution densities have been determined for aqueous solutions of thymidine at T = (288.15, 298.15, 303.15, and 313.15) K. The partial molar volumes at infinite dilution, V 2 0 , obtained from the density data were used to derive the partial molar isobaric expansion at infinite dilution for thymidine at T = 298.15 K, E 2 0 {E 2 0 =(∂V 2 0 /∂T) p }. The partial molar heat capacity at infinite dilution for thymidine, C p,2 0 , at T = 298.15 K has also been determined. Sound speeds have been measured for aqueous solutions of thymidine at T = 298.15 K. The partial molar isentropic compression at infinite dilution, K S,2 0 , and the partial molar isothermal compression at infinite dilution, K T,2 0 {K T,2 0 =-(∂V 2 0 /∂P) T }, have been derived from the sound speed data. The V 2 0 , E 2 0 , C p,2 0 , and K S,2 0 results for thymidine are critically compared with those available from the literature.
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
Formation of Ni(Al, Mo) solid solutions by mechanical alloying and their ordering on heating
International Nuclear Information System (INIS)
Portnoj, V.K.; Tomilin, I.A.; Blinov, A.M.; Kulik, T.
2002-01-01
The Ni(Al, Mo) solid solutions with different crystalline lattice periods (0.3592 and 0.3570 nm correspondingly) are formed in the course of the Ni 70 Al 25 Mo 5 and Ni 75 Al 20 Mo 5 powder mixtures mechanical alloying (MA) (through the mechanical activation in a vibrating mill). After MA the Mo atoms in the Ni 75 Al 20 Mo 5 mixture completely replace the aluminium positions with formation of the Ni 75 (AlMo) 25 (the L1 2 -type) ternary ordered phase, whereby such a distribution remains after heating up to 700 deg C. The Ni(Al, Mo) metastable solution is formed by MA in the Ni 75 Al 20 Mo 5 mixture, which decays with the release of molybdenum and the remained aluminide undergoes ordering by the L1 2 -type [ru
International Nuclear Information System (INIS)
McMillan, B.F.; Jolliet, S.; Tran, T.M.; Villard, L.; Bottino, A.; Angelino, P.
2010-01-01
Fluctuating quantities in magnetic confinement geometries often inherit a strong anisotropy along the field lines. One technique for describing these structures is the use of a certain set of Fourier components on the tori of nested flux surfaces. We describe an implementation of this approach for solving partial differential equations, like Poisson's equation, where a different set of Fourier components may be chosen on each surface according to the changing safety factor profile. Allowing the resolved components to change to follow the anisotropy significantly reduces the total number of degrees of freedom in the description. This can permit large gains in computational performance. We describe, in particular, how this approach can be applied to rapidly solve the gyrokinetic Poisson equation in a particle code, ORB5 (Jolliet et al. (2007) [5]), with a regular (non-field-aligned) mesh. (authors)
Patched based methods for adaptive mesh refinement solutions of partial differential equations
Energy Technology Data Exchange (ETDEWEB)
Saltzman, J.
1997-09-02
This manuscript contains the lecture notes for a course taught from July 7th through July 11th at the 1997 Numerical Analysis Summer School sponsored by C.E.A., I.N.R.I.A., and E.D.F. The subject area was chosen to support the general theme of that year`s school which is ``Multiscale Methods and Wavelets in Numerical Simulation.`` The first topic covered in these notes is a description of the problem domain. This coverage is limited to classical PDEs with a heavier emphasis on hyperbolic systems and constrained hyperbolic systems. The next topic is difference schemes. These schemes are the foundation for the adaptive methods. After the background material is covered, attention is focused on a simple patched based adaptive algorithm and its associated data structures for square grids and hyperbolic conservation laws. Embellishments include curvilinear meshes, embedded boundary and overset meshes. Next, several strategies for parallel implementations are examined. The remainder of the notes contains descriptions of elliptic solutions on the mesh hierarchy, elliptically constrained flow solution methods and elliptically constrained flow solution methods with diffusion.
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.
Energy Technology Data Exchange (ETDEWEB)
Wang, Yuezhong, E-mail: wyzphysics@163.com [Department of Physics and Key Laboratory for Radiation Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610064 (China); Tianjin Jinhang Institute of Technical Physics, Tianjin 300192 (China); Lu, Tiecheng, E-mail: lutiecheng@scu.edu.cn [Department of Physics and Key Laboratory for Radiation Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610064 (China); International Center for Material Physics, Chinese Academy of Sciences, Shenyang 110015 (China); Zhang, Rongshi [Tianjin Jinhang Institute of Technical Physics, Tianjin 300192 (China); Jiang, Shengli; Qi, Jianqi; Wang, Ying [Department of Physics and Key Laboratory for Radiation Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610064 (China); Chen, Qingyun [Department of Physics and Key Laboratory for Radiation Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610064 (China); National Defense Key Discipline Laboratory of Nuclear Waste and Environmental Safety, Southwest University of Science and Technology, Mianyang 621010 (China); Miao, Naihua [Physique Theorique des Materiaux, Universite de Liege, Sart Tilman B-4000 (Belgium); He, Duanwei [Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610064 (China)
2013-01-25
Highlights: Black-Right-Pointing-Pointer We reassess the chemical bonding character of {gamma}-AlON which shows strong ionicity. Black-Right-Pointing-Pointer {gamma}-AlON single-crystals exhibit highly elastic anisotropy. Black-Right-Pointing-Pointer The thermodynamic properties are investigated in a wider temperature/pressure range. Black-Right-Pointing-Pointer {gamma}-AlON is an O/N partially disordered structure. - Abstract: Spinel aluminium oxynitride ({gamma}-AlON), as a kind of transparent ceramic material expectable, is studied using the ab initio density functional method, in terms of electronic, elastic, thermodynamic properties and structure disorder. The results show that {gamma}-AlON exhibits strong ionicity, as quantitatively expressed by (Al{sub O}{sup 2.43+}){sub 15}(Al{sub T}{sup 2.41+}){sub 8}(O{sup 1.64-}){sub 27}(N{sup 2.27-}){sub 5} from our reassessment of the ionic character. We summarize and speculate that the considered oxynitride single-crystals exhibit highly elastic anisotropy. The interpretation of the thermodynamic properties of {gamma}-AlON according to quasi-harmonic Debye model confirm the available experiments and are extended to a wider temperature/pressure range. This material holds high elastic strength under extreme environments, where dB/dT absolute value is less than 0.03 GPa/K, independent of the pressure. Finally, we study the O/N structure disorder character of {gamma}-AlON solid solution by investigating nine possible crystal structures. It is found that {gamma}-AlON should be partially disordered, and in fact, the O/N ordering has a significant effect on the properties.
International Nuclear Information System (INIS)
Wang, Yuezhong; Lu, Tiecheng; Zhang, Rongshi; Jiang, Shengli; Qi, Jianqi; Wang, Ying; Chen, Qingyun; Miao, Naihua; He, Duanwei
2013-01-01
Highlights: ► We reassess the chemical bonding character of γ-AlON which shows strong ionicity. ► γ-AlON single-crystals exhibit highly elastic anisotropy. ► The thermodynamic properties are investigated in a wider temperature/pressure range. ► γ-AlON is an O/N partially disordered structure. - Abstract: Spinel aluminium oxynitride (γ-AlON), as a kind of transparent ceramic material expectable, is studied using the ab initio density functional method, in terms of electronic, elastic, thermodynamic properties and structure disorder. The results show that γ-AlON exhibits strong ionicity, as quantitatively expressed by (Al O 2.43+ ) 15 (Al T 2.41+ ) 8 (O 1.64- ) 27 (N 2.27- ) 5 from our reassessment of the ionic character. We summarize and speculate that the considered oxynitride single-crystals exhibit highly elastic anisotropy. The interpretation of the thermodynamic properties of γ-AlON according to quasi-harmonic Debye model confirm the available experiments and are extended to a wider temperature/pressure range. This material holds high elastic strength under extreme environments, where dB/dT absolute value is less than 0.03 GPa/K, independent of the pressure. Finally, we study the O/N structure disorder character of γ-AlON solid solution by investigating nine possible crystal structures. It is found that γ-AlON should be partially disordered, and in fact, the O/N ordering has a significant effect on the properties.
Complexon Solutions in Freon for Decontamination of Solids and SNF Treatment
International Nuclear Information System (INIS)
Kamachev, V.; Shadrin, A.; Murzin, A.
2008-01-01
Full text of publication follows: The possibility of using complexon solutions in supercritical and compressed carbon dioxide for decontamination of solid surfaces and for spent nuclear fuel (SNF) treatment was demonstrated in the works of Japanese, Russian and American researchers. The obtained data showed that the use of complexon solutions in carbon dioxide sharply decreases the volume of secondary radioactive wastes because it can be easily evaporated, purified and recycled. Moreover, high penetrability of carbon dioxide allows decontamination of surfaces with complex shape. However, one of the disadvantages of carbon dioxide is its high working pressure (10-20 MPa for supercritical CO 2 and 7 MPa for compressed CO 2 ). Moreover, in case of SNF treatment, carbon dioxide solvent will be contaminated with 14 C, which in the course of SNF dissolution in CO 2 containing TBP*HNO 3 adduct stage will be oxidized into CO 2 . These main disadvantages can be eliminated by using complexon solutions in ozone-friendly Freon HFC-134a for decontamination and SNF treatment. Our experimental data for real contaminated materials showed that the decontamination factor for complexon solutions in liquid Freon HFC-134a at 1,2 MPa and 25 deg. C is close to that attained in carbon dioxide. Moreover, the possibility of SNF treatment in Freon HFC-134a was demonstrated in trials using real SNF and its imitators. (authors)
Energy Technology Data Exchange (ETDEWEB)
Zurhelle, Alexander F.; Souza, Roger A. de [Institute of Physical Chemistry, RWTH Aachen University (Germany); Tong, Xiaorui; Mebane, David S. [Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown, WV (United States); Klein, Andreas [Institute of Materials Science, TU Darmstadt (Germany)
2017-11-13
A space-charge theory applicable to concentrated solid solutions (Poisson-Cahn theory) was applied to describe quantitatively as a function of temperature and oxygen partial pressure published data obtained by in situ X-ray photoelectron spectroscopy (XPS) for the concentration of Ce{sup 3+} (the reactive species) at the surface of the oxide catalyst Ce{sub 0.8}Sm{sub 0.2}O{sub 1.9}. In contrast to previous theoretical treatments, these calculations clearly indicate that the surface is positively charged and compensated by an attendant negative space-charge zone. The high space-charge potential that develops at the surface (>0.8 V) is demonstrated to be hardly detectable by XPS measurements because of the short extent of the space-charge layer. This approach emphasizes the need to take into account defect interactions and to allow deviations from local charge neutrality when considering the surfaces of oxide catalysts. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)
Directory of Open Access Journals (Sweden)
Hans-Jörg Schneider
2015-03-01
Full Text Available The lock-and-key concept is discussed with respect to necessary extensions. Formation of supramolecular complexes depends not only, and often not even primarily on an optimal geometric fit between host and guest. Induced fit and allosteric interactions have long been known as important modifications. Different binding mechanisms, the medium used and pH effects can exert a major influence on the affinity. Stereoelectronic effects due to lone pair orientation can lead to variation of binding constants by orders of magnitude. Hydrophobic interactions due to high-energy water inside cavities modify the mechanical lock-and-key picture. That optimal affinities are observed if the cavity is only partially filled by the ligand can be in conflict with the lock-and-key principle. In crystals other forces than those between host and guest often dominate, leading to differences between solid state and solution structures. This is exemplified in particular with calixarene complexes, which by X-ray analysis more often than other hosts show guest molecules outside their cavity. In view of this the particular problems with the identification of weak interactions in crystals is discussed.
Mishra, P. K.; Neuman, S. P.
2009-12-01
Tartakovsky and Neuman [2007] developed an analytical solution for flow to a partially penetrating well pumping at a constant rate from a compressible unconfined aquifer considering an unsaturated zone of infinite thickness. In their solution three-dimensional, axially symmetric unsaturated flow was described by a linearized version of Richards’ equation in which both relative hydraulic conductivity and water content vary exponentially with incremental capillary pressure head relative to its air entry value. Both exponential functions were characterized by a common exponent. We present an improved solution in which relative hydraulic conductivity and water content are characterized by separate parameters and the unsaturated zone has finite thickness. Our four-parameter representation of these functions is more flexible than the three-parameter version of Mathias and Butler [2006], who consider flow in the unsaturated zone to be strictly vertical and the pumping well to be fully penetrating. We investigate the effects of unsaturated zone thickness and constitutive parameters on drawdown in the unsaturated and saturated zones as functions of position and time. We then use our new solution to analyze data from synthetic and real pumping tests.
Crystalline structure and electrical properties of Dy1-XCaXMnO3 solid solution
Directory of Open Access Journals (Sweden)
Durán, P.
2002-12-01
Full Text Available Solid solutions corresponding to the Dy1-xCaXMnO3 system, x=0.0 to 0.60 have been studied. The powders were prepared by solid state reaction of the corresponding oxides and carbonates. Sintered bodies were obtained by firing between 1250 and 1450ºC. All the compositions showed single-phased perovskite-type structure with orthorhombic symmetry and Space Group Pbnm. Increase of the CaO content leads to a monotonic decrease of the orthorhombicity factor b/a with the Ca2+ concentration up to x=0.60. All the solid solutions crystallised with the same O’-type orthorhombic perovskite structure such as pure DyMnO3. Electrical measurements have shown semiconducting behaviour for all the solid solutions. The room temperature conductivity increases monotonically with the CaO content. The 60/40 Ca/Dy composition showed a high value of the electrical conductivity and a correlative very low value of the activation energy. Thermally activated small polaron hopping mechanism controls the conductivity of these perovskite ceramics.Se han estudiado soluciones sólidas correspondientes al sistema Dy1-xCaxMnO3, x=0.0 a 0.60. Los polvos cerámicos fueron preparados por reacción en estado sólido de los correspondientes óxidos y carbonatos. Los materiales cerámicos se obtuvieron por sinterización entre 1250º y 1450ºC. Todas las composiciones fueron monofásicas y mostraron una estructura tipo perovskita, con simetría ortorrómbica y Grupo Espacial Pbnm. El aumento del contenido en CaO llevó a una disminución monótona del factor de ortorrombicidad, b/a. Todas las soluciones sólidas cristalizaron con el mismo tipo de estructura perovskita ortorrómbica O’, como la del compuesto puro DyMnO3. Las medidas eléctricas mostraron comportamiento semiconductor en todas las soluciones sólidas. La conductividad a temperatura ambiente aumenta monótonamente con el contenido de CaO. La composición 60/40 mostró un elevado valor de conductividad y un correlativo
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)
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.
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.
Local structural relaxation around Co2+ along the hardystonite-Co-åkermanite melilite solid solution
Ardit, Matteo; Cruciani, Giuseppe; Dondi, Michele
2012-10-01
Six pure compounds belonging to the hardystonite (Ca2ZnSi2O7)-Co-åkermanite (Ca2CoSi2O7) solid solution were investigated by the combined application of X-ray powder diffraction and electronic absorption spectroscopy. Structural refinements of the XRPD data revealed a negative excess volume of mixing due to the single isovalent substitution of Co for Zn in the tetrahedral site. In agreement with the diffraction data, deconvolution of the optical spectra showed a progressive decreasing of the crystal field strength parameter 10 Dq moving toward the Co-åkermanite end-member, meaning that the local cobalt-oxygen bond distance, Co}}{-}{{O}}rangle^{{local}} , increased along the join with the amount of cobalt. The calculated structural relaxation coefficient around the fourfold coordinated Co2+ in the Ca2(Zn1- x Co x )Si2O7 join was ɛ = 0.69, very far from the one predicted by the Vegard's law ( ɛ = 0) and at variance with ɛ = 0.47 previously found for tetrahedrally coordinated Co2+ in gahnite-Co-aluminate spinel solid solution. This difference is consistent with the largest constraints existing on the spinel structure, based on cubic closest packing, compared to the more flexible layered melilite structure.
Energy Technology Data Exchange (ETDEWEB)
Pietraszkiewicz, Marek, E-mail: mpietraszkiewicz@ichf.edu.pl [Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw (Poland); Pietraszkiewicz, Oksana; Karpiuk, Jerzy; Majka, Alina [Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw (Poland); Dutkiewicz, Grzegorz; Borowiak, Teresa [Adam Mickiewicz University, Faculty of Chemistry, Department of Crystallography, Grunwaldzka 6, 60-780 Poznań (Poland); Kaczmarek, Anna M. [L3–Luminescent Lanthanide Lab, f-element coordination chemistry, Ghent University, Department of Inorganic and Physical Chemistry, Krijgslaan 281, Building S3, 9000 Gent (Belgium); Van Deun, Rik, E-mail: rik.vandeun@ugent.be [L3–Luminescent Lanthanide Lab, f-element coordination chemistry, Ghent University, Department of Inorganic and Physical Chemistry, Krijgslaan 281, Building S3, 9000 Gent (Belgium)
2016-02-15
Tetraphenylimidodiphosphinate (tpip) forms neutral 3:1 complexes with lanthanide ions. These complexes can accommodate one ancillary planar heterocyclic ligand to complement their coordination sphere of Eu{sup 3+} to coordination number 8. Several co-ligands were tested to form new complexes: 1,10-phenanthroline, bathophenanthroline, 2,4,6-tris(2-pyridyl)-1,3,5-triazine, dipyrido[3,2-f:2′,3′-h]quinoxaline and 2,2′:6′,2′′-terpyridine. The addition of heterocyclic N,N-bidentate co-ligands to the coordination sphere results in a dramatic (by a factor of 45–50) luminescence enhancement of the parent Eu(tpip){sub 3}. The solid-state measurements confirmed that the ancillary ligands strongly increased the photoluminescence quantum yield (PLQY) of the investigated complexes. - Highlights: • We have disovered highly photoluminescent ternary Eu(III) complexes. • They consist of Eu(III) tetraphenylimidodiphosphinate, and planar heterocyclic ligands. • The increase in photoluminescence quantum yields in solution is enhanced up to 50 times in solution. • The solid-state photoluminescence exceeds 80% at room temperature.
Jungbauer, Stefan H; Schindler, Severin; Herdtweck, Eberhardt; Keller, Sandro; Huber, Stefan M
2015-09-21
The binding properties of neutral halogen-bond donors (XB donors) bearing two multidentate Lewis acidic motifs toward halides were investigated. Employing polyfluorinated and polyiodinated terphenyl and quaterphenyl derivatives as anion receptors, we obtained X-ray crystallographic data of the adducts of three structurally related XB donors with tetraalkylammonium chloride, bromide, and iodide. The stability of these XB complexes in solution was determined by isothermal titration calorimetry (ITC), and the results were compared to X-ray analyses as well as to calculated binding patterns in the gas phase. Density functional theory (DFT) calculations on the gas-phase complexes indicated that the experimentally observed distortion of the XB donors during multiple multidentate binding can be reproduced in 1:1 complexes with halides, whereas adducts with two halides show a symmetric binding pattern in the gas phase that is markedly different from the solid state structures. Overall, this study demonstrates the limitations in the transferability of binding data between solid state, solution, and gas phase in the study of complex multidentate XB donors. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Solubility of jarosite solid solutions precipitated from acid mine waters, Iron Mountain, California
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.
International Nuclear Information System (INIS)
Pietraszkiewicz, Marek; Pietraszkiewicz, Oksana; Karpiuk, Jerzy; Majka, Alina; Dutkiewicz, Grzegorz; Borowiak, Teresa; Kaczmarek, Anna M.; Van Deun, Rik
2016-01-01
Tetraphenylimidodiphosphinate (tpip) forms neutral 3:1 complexes with lanthanide ions. These complexes can accommodate one ancillary planar heterocyclic ligand to complement their coordination sphere of Eu 3+ to coordination number 8. Several co-ligands were tested to form new complexes: 1,10-phenanthroline, bathophenanthroline, 2,4,6-tris(2-pyridyl)-1,3,5-triazine, dipyrido[3,2-f:2′,3′-h]quinoxaline and 2,2′:6′,2′′-terpyridine. The addition of heterocyclic N,N-bidentate co-ligands to the coordination sphere results in a dramatic (by a factor of 45–50) luminescence enhancement of the parent Eu(tpip) 3 . The solid-state measurements confirmed that the ancillary ligands strongly increased the photoluminescence quantum yield (PLQY) of the investigated complexes. - Highlights: • We have disovered highly photoluminescent ternary Eu(III) complexes. • They consist of Eu(III) tetraphenylimidodiphosphinate, and planar heterocyclic ligands. • The increase in photoluminescence quantum yields in solution is enhanced up to 50 times in solution. • The solid-state photoluminescence exceeds 80% at room temperature.
Gunzburger, M. D.; Nicolaides, R. A.
1986-01-01
Substructuring methods are in common use in mechanics problems where typically the associated linear systems of algebraic equations are positive definite. Here these methods are extended to problems which lead to nonpositive definite, nonsymmetric matrices. The extension is based on an algorithm which carries out the block Gauss elimination procedure without the need for interchanges even when a pivot matrix is singular. Examples are provided wherein the method is used in connection with finite element solutions of the stationary Stokes equations and the Helmholtz equation, and dual methods for second-order elliptic equations.
Malama, Bwalya; Kuhlman, Kristopher L.; Barrash, Warren
2008-07-01
SummaryA semi-analytical solution is presented for the problem of flow in a system consisting of unconfined and confined aquifers, separated by an aquitard. The unconfined aquifer is pumped continuously at a constant rate from a well of infinitesimal radius that partially penetrates its saturated thickness. The solution is termed semi-analytical because the exact solution obtained in double Laplace-Hankel transform space is inverted numerically. The solution presented here is more general than similar solutions obtained for confined aquifer flow as we do not adopt the assumption of unidirectional flow in the confined aquifer (typically assumed to be horizontal) and the aquitard (typically assumed to be vertical). Model predicted results show significant departure from the solution that does not take into account the effect of leakage even for cases where aquitard hydraulic conductivities are two orders of magnitude smaller than those of the aquifers. The results show low sensitivity to changes in radial hydraulic conductivities for aquitards that are two or more orders of magnitude smaller than those of the aquifers, in conformity to findings of earlier workers that radial flow in aquitards may be neglected under such conditions. Hence, for cases were aquitard hydraulic conductivities are two or more orders of magnitude smaller than aquifer conductivities, the simpler models that restrict flow to the radial direction in aquifers and to the vertical direction in aquitards may be sufficient. However, the model developed here can be used to model flow in aquifer-aquitard systems where radial flow is significant in aquitards.
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.
3He release characteristics of metal tritides and scandium--tritium solid solutions
International Nuclear Information System (INIS)
Perkins, W.G.; Kass, W.J.; Beavis, L.C.
1976-01-01
Tritides of such metals as Sc, Ti, and Er are useful materials for determining the effects of He accumulation in metallic solids, for example, CTR first wall materials. Such effects include lattice strain and gross deformation which are related to 3 He retention and ultimate release. Long term gas release studies have indicated that, during the early life of a metal ditritide, a large fraction of the 3 He is retained in the solid. At more advanced ages, the 3 He release rate becomes comparable to the generation rate. Statistical analysis of the data indicates that the acceleration in 3 He release rate depends on accumulated 3 He concentration rather than strictly on age. 3 He outgassing results are presented for thin films of ScT 2 , TiT 2 , and ErT 2 , and the critical 3 He concentrations are discussed in terms of a percolation model. Phase transformations which occur on tritide formation cast some doubt on the validity of extrapolating results obtained for metal tritides to predictions regarding the accumulation of helium in metals. Sc is unique among the early transition and rare-earth metals in that the metal exhibits a very high room temperature T solubility (T/Sc = 0.4) with no phase transformation. Indeed, even the lattice parameters of the hcp Sc lattice are only minimally changed by T solution. Single crystal ScT/sub 0.3/ samples in two crystallographic orientations were obtained. Using a very sensitive technique, 3 He emission was measured from both these samples, as well as from fine-grained thin film Sc--T solid solution samples (ScT/sub 0.3-0.4/). The fine-grained film samples release 3 He at 2-3 percent of the generation rate, while the emission rate from the single-crystal samples is approximately 0.05 percent of the generation rate, indicating a strong grain size effect
Investigating conceptual models for physical property couplings in solid solution models of cement
International Nuclear Information System (INIS)
Benbow, Steven; Watson, Claire; Savage, David
2005-11-01
The long-term behaviour of cementitious engineered barriers is an important process to consider when modelling the migration of radionuclides from a geological repository for nuclear waste. The modelling of cement is complicated by the fact that the cement is dominated by the behaviour of calcium silicate hydrate (CSH) gel which is a complex solid exhibiting incongruent dissolution behaviour. In this report, we have demonstrated the implementation of a solid-solution CSH gel model within a geochemical transport modelling framework using the Raiden computer code to investigate cement/concrete-groundwater interactions. The modelling conducted here shows that it is possible to couple various conceptual models for the evolution of physical properties of concrete with a solid solution model for cement degradation in a fully coupled geochemical transport model to describe the interaction of cement/concrete engineered barriers with groundwater. The results show that changes to the conceptual models and flow rates can give rise to very different evolutions. Most simulations were carried out at a reduced 'experimental' scale rather than full repository scale. The work has shown the possibility to investigate also the changing physical properties of degrading cement. To further develop the model more emphasis is needed on kinetics and the detailed development of a nearly clogged pore space. Modelling of the full repository scale could be another way forward to understand the behaviour of degrading concrete. A general conclusion is that the combined effects of chemical evolution and physical degradation should be analysed in performance assessments of cementitious repositories. Moreover, the project results will be used as one basis in coming reviews of SKB's safety assessments of repositories for spent fuel and low-and intermediate level waste
Investigating conceptual models for physical property couplings in solid solution models of cement
Energy Technology Data Exchange (ETDEWEB)
Benbow, Steven; Watson, Claire; Savage, David [Quintesssa Ltd., Henley-on-Thames (United Kingdom)
2005-11-15
The long-term behaviour of cementitious engineered barriers is an important process to consider when modelling the migration of radionuclides from a geological repository for nuclear waste. The modelling of cement is complicated by the fact that the cement is dominated by the behaviour of calcium silicate hydrate (CSH) gel which is a complex solid exhibiting incongruent dissolution behaviour. In this report, we have demonstrated the implementation of a solid-solution CSH gel model within a geochemical transport modelling framework using the Raiden computer code to investigate cement/concrete-groundwater interactions. The modelling conducted here shows that it is possible to couple various conceptual models for the evolution of physical properties of concrete with a solid solution model for cement degradation in a fully coupled geochemical transport model to describe the interaction of cement/concrete engineered barriers with groundwater. The results show that changes to the conceptual models and flow rates can give rise to very different evolutions. Most simulations were carried out at a reduced 'experimental' scale rather than full repository scale. The work has shown the possibility to investigate also the changing physical properties of degrading cement. To further develop the model more emphasis is needed on kinetics and the detailed development of a nearly clogged pore space. Modelling of the full repository scale could be another way forward to understand the behaviour of degrading concrete. A general conclusion is that the combined effects of chemical evolution and physical degradation should be analysed in performance assessments of cementitious repositories. Moreover, the project results will be used as one basis in coming reviews of SKB's safety assessments of repositories for spent fuel and low-and intermediate level waste.
Givan, A. V.
2009-12-01
Science is supposed to be about talent devoid of the bias’ and judgments generated by background, gender, ethnicity or any culturally determined discriminators. The scientific, academic, corporate and government communities have a vested interest in developing models, practices and policies that significantly increase the number of U.S. graduates in scientific disciplines. Additionally, it is crucial that these graduates possess the essential competencies and creative problem solving skills to compete in the current global economy. The stakeholders (corporations, researchers, educational practitioners, policymakers and funders) who have the common goal of producing highly qualified scientists must commit to collaborate in developing innovative strategies and solutions to this complex challenge. Volumes of research data from a variety of sources such the social and cognitive sciences, educational psychology, National Science Foundation and non-profit groups have been and are available for use enabling us to rise to the challenge we have been charged with, and are responsible for the outcome. A proposed solution to part of the challenge and discussion of the impacts of increasing diversity in science will be discussed in this paper. The paper will address one element of the issue - strategies for the recruitment and retention of under-represented groups in science focusing on the historical and current culture, climate and barriers encountered by minorities as they progress through the educational system and career pathways. The paper will examine the benefits of diversity to the individual and society as a whole.
A partial solution: a local mental health authority for the UK.
Hadley, Trevor R.; Goldman, Howard H.
1998-07-01
BACKGROUND: the structural problems of the mental health system in the UK have been analyzed by a number of authors over the past several years as the "reforms" of the health and social service systems have continued (Kavanagh and Knapp, 1995; Mechanic, 1995). In a recent article, Hadley and Goldman (1995) suggest that one possible solution to some of these issues may be the creation of a local mental health authority. Such an authority would consolidate the funding, authority and responsibility in a single entity. We believe this model, which is typical of many local public mental health systems in the US, is at least part of the solution to the current problem of financial and service fragmentation of the current system in the UK. The numerous "reforms" of the health and social service systems (which include the Community Care Act, the development of the Internal Market, GP fundholding and the purchaser-provider split) were not designed for the care of the mentally ill (Han, 1996). These policy changes in the design of health and social services have created a complicated and difficult context in which services must be delivered. Too many agencies play a significant role in the delivery and management of mental health services. Health authorities, social service agencies and GP fundholders are direct and indirect funders of the system while community care trusts, social service agencies and GPs are service providers (Hadley, 1996a). RESULTS AND A PROPOSAL: We believe that the development of local mental health authorities may be part of the solution to the structural and economic problems of the current system in the UK. It is not the answer to limited resources or limited skills, but can create a new structure, which will permit and encourage the cooperation and innovation that is now possible only with unusual effort. Local mental health authorities have a number of crucial characteristics, but, most importantly, they refocus the system on the provision of care
International Nuclear Information System (INIS)
Dehghan, Mehdi; Shakeri, Fatemeh
2007-01-01
In this work, the solution of an inverse problem concerning a diffusion equation with source control parameters is presented. The homotopy perturbation method is employed to solve this equation. This method changes a difficult problem into a simple problem which can be easily solved. In this procedure, according to the homotopy technique, a homotopy with an embedding parameter p element of [0,1] is constructed, and this parameter is considered a 'small parameter', so the method is called the homotopy perturbation method, which can take full advantage of the traditional perturbation method and homotopy technique. The approximations obtained by the proposed method are uniformly valid not only for small parameters, but also for very large parameters. The fact that this technique, in contrast to the traditional perturbation methods, does not require a small parameter in the system, leads to wide applications in nonlinear equations
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.
Erping, Li; Haoyun, Chen; Yanyang, Shang; Jun, Pan; Qing, Hu
2017-11-01
In this paper, the pyrolysis characteristics of six typical components in municipal solid waste (MSW) were investigated through a TG-FTIR combined technique and it was concluded that the main pyrolysis process of the biomass components (including food residues, sawdust and paper) occurred at 150-600°C. The main volatiles were multi-component gas including H 2 O, CO 2 , and CO. The main pyrolysis temperatures of three artificial products (PP, PVC and leather) was ranged from 200to 500°C. The wavelength of small molecule gases (CH 4 , CO 2 and CO) and the the chemical bonds (CO and CC) were observed in the infrared spectrum Based on the pyrolysis temperature interval and volatile constituent, a new "double-solution" process of pyrolysis and oxygen-enrichment decomposition MSW was designed. To achieve this process, a double-solution project was built for the direct treatment of MSW (10t/d). The complete setup of equipment and analysis of the byproducts has been reported in this paper to indicate the performance of this process. Energy balance and economic benefits were analysed for the process supporting. It was successfully demonstrated that the double-solution process was the environmentally friendly alternative method for MSW treatment in Chinese rural areas. Copyright © 2017 Elsevier Ltd. All rights reserved.
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.
International Nuclear Information System (INIS)
Chezhina, N.V.; Kuznetsova, I.V.
1995-01-01
Solid solutions of LaCa 0.5 Sr 0.5 Ni x Al 1-x O 4 (0≤x≤0.10) have been synthesized and their magnetic susceptibility in the temperature range of 77-400 K has been studied. The change in the basic state of nickel atoms in case of partial substitution of calcium for strontium atoms has been studied. The change in the basic state of nickel atoms in case of partial substitution of calcium for strontium atoms has been studied, as well as the way it affects exchange interaction in a complex oxide. It is shown that the substitution results in increase of the degree of paramagnetic atoms aggregation in solid solution. 9 refs., 2 figs., 1 tab
Interactive dualism as a partial solution to the mind-brain problem for psychiatry.
McLaren, N
2006-01-01
With the collapse of the psychoanalytic and the behaviorist models, and the failure of reductive biologism to account for mental life, psychiatry has been searching for a broad, integrative theory on which to base daily practice. The most recent attempt at such a model, Engel's 'biopsychosocial model', has been shown to be devoid of any scientific content, meaning that psychiatry, alone among the medical disciplines, has no recognised scientific basis. It is no coincidence that psychiatry is constantly under attack from all quarters. In order to develop, the discipline requires an integrative and interactive model which can take account of both the mental and the physical dimensions of human life, yet still remain within the materialist scientific ethos. This paper proposes an entirely new model of mind based in Chalmers' 'interactive dualism' which satisfies those needs. It attributes the causation of all behaviour to mental life, but proposes a split in the nature of mentality such that mind becomes a composite function with two, profoundly different aspects. Causation is assigned to a fast, inaccessible cognitive realm operating within the brain machinery while conscious experience is seen as the outcome of a higher order level of brain processing. The particular value of this model is that it immediately offers a practical solution to the mind-brain problem in that, while all information-processing takes place in the mental realm, it is not in the same order of abstraction as perception. This leads to a model of rational interaction which acknowledges both psyche and soma. It can fill the gap left by the demise of Engel's empty 'biopsychosocial model'.
Energy Technology Data Exchange (ETDEWEB)
Momma, Akihiko; Takano, Kiyonami; Tanaka, Yohei; Negishi, Akira; Kato, Ken; Nozaki, Ken; Kato, Tohru [Energy Technology Research Institute, National Institute of Advanced Industrial Science and Technology, 1-1-1 Umezono Tsukuba Ibaraki, 305-8568 (Japan); Ichigi, Takenori; Matsuda, Kazuyuki; Ryu, Takashi [Application Development Project, Corporate R and D, NGK Insulators, Ltd., 2-56 Suda-cho Mizuho-ku Nagoya-shi Aichi, 467-8530 (Japan)
2009-08-01
In order to investigate the internal reforming characteristics in a cermet supported solid oxide fuel cell (SOFC) using YSZ as the electrolyte, the concentration profiles of the gaseous species along the gas flow direction in the anode were measured. Partially reformed methane using a pre-reformer kept at a constant temperature is supplied to the center of the cell which is operated with a seal-less structure at the gas outlet. The anode gas is sucked in via silica capillaries to the initially evacuated gas tanks. The process is simultaneously carried out using five sampling ports. The sampled gas is analyzed by a gas chromatograph. Most of the measurements are made at the cell temperature (T{sub cell}) of 750 C and at various temperatures of the pre-reformer (T{sub ref}) with various fuel utilizations (U{sub f}) of the cell. The composition of the fuel at the inlet of the anode was confirmed to be almost the same as that theoretically calculated assuming equilibrium at the temperature of the pre-reformer. The effect of internal reforming in the anode is clearly observed as a steady decrease in the methane concentration along the flow axis. The effect of the water-gas shift reaction is also observed as a decrease in the CO{sub 2} concentration and an increase of CO concentration around the gas inlet region, as the water-gas shift reaction inversely proceeds when T{sub cell} is higher than T{sub ref}. The diffusion of nitrogen from the seal-less outermost edge is observed, and the diffusion is confirmed to be more significant as U{sub f} decreases. The observations are compared with the results obtained by the SOFC supported by lanthanum gallate electrolyte. With respect to the internal reforming performance, the cell investigated here is found to be more effective when compared to the previously reported electrolyte supported cell. (author)
Momma, Akihiko; Takano, Kiyonami; Tanaka, Yohei; Negishi, Akira; Kato, Ken; Nozaki, Ken; Kato, Tohru; Ichigi, Takenori; Matsuda, Kazuyuki; Ryu, Takashi
In order to investigate the internal reforming characteristics in a cermet supported solid oxide fuel cell (SOFC) using YSZ as the electrolyte, the concentration profiles of the gaseous species along the gas flow direction in the anode were measured. Partially reformed methane using a pre-reformer kept at a constant temperature is supplied to the center of the cell which is operated with a seal-less structure at the gas outlet. The anode gas is sucked in via silica capillaries to the initially evacuated gas tanks. The process is simultaneously carried out using five sampling ports. The sampled gas is analyzed by a gas chromatograph. Most of the measurements are made at the cell temperature (T cell) of 750 °C and at various temperatures of the pre-reformer (T ref) with various fuel utilizations (U f) of the cell. The composition of the fuel at the inlet of the anode was confirmed to be almost the same as that theoretically calculated assuming equilibrium at the temperature of the pre-reformer. The effect of internal reforming in the anode is clearly observed as a steady decrease in the methane concentration along the flow axis. The effect of the water-gas shift reaction is also observed as a decrease in the CO 2 concentration and an increase of CO concentration around the gas inlet region, as the water-gas shift reaction inversely proceeds when T cell is higher than T ref. The diffusion of nitrogen from the seal-less outermost edge is observed, and the diffusion is confirmed to be more significant as U f decreases. The observations are compared with the results obtained by the SOFC supported by lanthanum gallate electrolyte. With respect to the internal reforming performance, the cell investigated here is found to be more effective when compared to the previously reported electrolyte supported cell.
Sun, Shuyu; Salama, Amgad; El-Amin, Mohamed
2012-01-01
A new technique for the numerical solution of the partial differential equations governing transport phenomena in porous media is introduced. In this technique, the governing equations as depicted from the physics of the problem are used without extra manipulations. In other words, there is no need to reduce the number of governing equations by some sort of mathematical manipulations. This technique enables the separation of the physics part of the problem and the solver part, which makes coding more robust and could be used in several other applications with little or no modifications (e.g., multi-phase flow in porous media). In this method, one abandons the need to construct the coefficient matrix for the pressure equation. Alternatively, the coefficients are automatically generated within the solver routine. We show examples of using this technique to solving several flow problems in porous media.
Sun, Shuyu
2012-06-02
A new technique for the numerical solution of the partial differential equations governing transport phenomena in porous media is introduced. In this technique, the governing equations as depicted from the physics of the problem are used without extra manipulations. In other words, there is no need to reduce the number of governing equations by some sort of mathematical manipulations. This technique enables the separation of the physics part of the problem and the solver part, which makes coding more robust and could be used in several other applications with little or no modifications (e.g., multi-phase flow in porous media). In this method, one abandons the need to construct the coefficient matrix for the pressure equation. Alternatively, the coefficients are automatically generated within the solver routine. We show examples of using this technique to solving several flow problems in porous media.
High strength Ni based composite reinforced by solid solution W(Al) obtained by powder metallurgy
International Nuclear Information System (INIS)
Zhao Bo; Zhu Changjun; Ma Xianfeng; Zhao Wei; Tang Huaguo; Cai Shuguang; Qiao Zhuhui
2007-01-01
The solid-solution-particle reinforced W(Al)-Ni composites were successfully fabricated by using mechanical alloying (MA) and hot-pressing (HP) technique when the content of Ni is between 45 wt% and 55 wt%. Besides, samples of various original component ratio of Al 50 W 50 to Ni have been fabricated, and the corresponding microcomponents and mechanical properties such as microhardness, ultimate tensile strength and elongation were characterized and discussed. The optimum ultimate tensile strength under the experiment conditions is 1868 MPa with elongation of 10.21% and hardness of 6.62 GPa. X-ray diffraction (XRD), FE-SEM and energy dispersive analysis of X-rays (EDS) were given to analysis the components and morphology of the composite bulk specimens
Synthesis, characterization and thermal stability of solid solutions Zr (Y, Fe, MoO2
Directory of Open Access Journals (Sweden)
Felipe Legorreta-García
2015-05-01
Full Text Available The synthesis of Fe3+, Mo4+ and Y3+ fully stabilized zirconia by the nitrate/urea combustion route and thermal stability in air was investigated. The solid solution obtained was characterized by X ray diffraction (XRD, scanning electron microscopy (SEM and used the BET method for determining specific surface. The ceramic powders obtained were calcined at 1473 K in air atmosphere in order to determine their thermal stability. The scanning electron microscopy (SEM results showed a homogeneous grain surface, measuring several tens of micrometers across. The crystallographic study revealed that by this method it was successfully achieved zirconia doped with Fe3+, Mo4+ and Y3+ ions in the zirconia tetragonal monophase, even after calcinations.
International Nuclear Information System (INIS)
Meneghetti, Simoni Plentz; Lutz, Pierre J.; Duval, M.; Kress, Jacky; Lapp, A.
2001-01-01
Polyethylenes were obtained using palladium catalyst [(Ar N=C(Me)-C(Me)=N Ar) Pd(CH 2 ) 3 (COOMe)] + BAr' 4 - (VERSIPOL TM ); Ar2,6-i-Pr 2 -C 6 H 3 and Ar'3,5-(CF 3 ) 2 -C 6 H 3 . The combination of dilute solution and solid state characterization of these polyethylenes revealed strong differences between structural parameters of samples prepared under almost identical conditions except ethylene pressure (6, 3 and 1 bar). These differences can be explained by the fact that samples prepared at 6 bar are almost linear, with only a few short branches, whereas those synthesized at 1 bar are highly branched or even hyper branched. (author)
Synthesis, characterization and thermal stability of solid solutions Zr (Y, Fe, Mo)O {sub 2}
Energy Technology Data Exchange (ETDEWEB)
Legorreta-Garcia, F.; Esperanza Hernandez-Cruz, L.; Villanueva-Ibanez, M.; Flores-Gonzalez, M. A.
2015-10-01
The synthesis of Fe{sup 3}+, Mo{sup 4+} and Y{sup 3+} fully stabilized zirconia by the nitrate/urea combustion route and thermal stability in air was investigated. The solid solution obtained was characterized by X ray diffraction (XRD), scanning electron microscopy (SEM) and used the BET method for determining specific surface. The ceramic powders obtained were calcined at 1473 K in air atmosphere in order to determine their thermal stability. The scanning electron microscopy (SEM) results showed a homogeneous grain surface, measuring several tens of micrometers across. The crystallographic study revealed that by this method it was successfully achieved zirconia doped with Fe{sup 3+}, Mo{sup 4+} and Y{sup 3+} ions in the zirconia tetragonal monophase, even after calcinations. (Author)
International Nuclear Information System (INIS)
Dudnik, E.F.; Sinyakov, E.V.; Gene, V.V.
1977-01-01
The dielectric properties of the monocrystals of the ferroelastics Pb 3 (PO 4 ) 2 and Pb 3 (VO 4 ) 2 were investigated. The dependencies of dielectric permeability and double refraction upon temperature were measured. The domain structure and the effect of pressure upon it were studied. The influence of BaO, CaO and Cr 2 O 3 additions upon the properties of Pb 3 (V 4 ) 2 monocrystals and upon the system of monocrystalline solid solutions of Pb 3 (VO 4 ) 2 - Pb 3 (PO 4 ) 2 was also examined. Similar to the case of usual segnetoelectrics, introduction of additions into segnetoelastic crystals was found to lead to spreading of the phase transition
Internal friction and dislocation collective pinning in disordered quenched solid solutions
D'Anna, G.; Benoit, W.; Vinokur, V. M.
1997-12-01
We introduce the collective pinning of dislocations in disordered quenched solid solutions and calculate the macroscopic mechanical response to a small dc or ac applied stress. This work is a generalization of the Granato-Lücke string model, able to describe self-consistently short and long range dislocation motion. Under dc applied stress the long distance dislocation creep has at the microscopic level avalanche features, which result in a macroscopic nonlinear "glassy" velocity-stress characteristic. Under ac conditions the model predicts, in addition to the anelastic internal friction relaxation in the high frequency regime, a linear internal friction background which remains amplitude-independent down to a crossover frequency to a strongly nonlinear internal friction regime.
Double crystal X-ray analysis of phosphorus precipitation in supersaturated Si-P solid solutions
International Nuclear Information System (INIS)
Servidori, M.; Zini, Q.; Dal Monte, C.
1983-01-01
The physical nature of the electrically inactive phosphorus in silicon is investigated by double crystal X-ray diffraction measurements. This analysis is performed on laser annealed supersaturated samples, doped by ion implantation up to 5 x 10 21 cm -3 . After isothermal heat treatments, these solid solutions show marked reductions in the electrically active phosphorus concentration. In particular, 850 0 C heatings give rise to a carrier concentration which corresponds to the phosphorus solubility in equilibrium with the inactive dopant. This dopant is characterized by means of lattice strain measurements: they are found consistent with the presence of perfectly coherent cubic SiP precipitates. This result is in agreement with the one obtained in preceeding works by electrical measurements and transmission electron microscopy observations and contradicts the hypothesis that the excess dopant atoms are, at least in part, charged point defects (E-centres). (author)
Measurement test on creep strain rate of uranium-zirconium solid solutions
International Nuclear Information System (INIS)
Ogata, Takanari; Akabori, Mitsuo; Ogawa, Toru
1996-11-01
In order to measure creep strain rate of a small specimen of U-Zr solid solution, authors proposed an estimation method which was based upon the stress relaxation after compression. It was applied to measurement test on creep strain rate of the U-10wt%Zr specimen in the temperature range of 757 to 911degC. It may be concluded that the proposed method is valid, provided that the strain is within the appropriate range and that sufficient amount of the load decrement is observed. The obtained creep rate of U-10wt%Zr alloy indicated significantly smaller value, compared to the experimental data for pure U metal and evaluated data for U-Pu-Zr alloy. However, more careful measurement is desired in future since the present data are thought to be influenced by the precipitations included in the specimen. (author)
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)
Variable valence of praseodymium in rare-earth oxide solid solutions
International Nuclear Information System (INIS)
Kravchinskaya, M.V.; Merezhinskii, K.Y.; Tikhonov, P.A.
1986-01-01
Solid solutions of elevated praseodymium oxide content have interesting electrical properties, making them the basis for the manufacture of high-temperature electrically conducting materials. Establishment of the composition-structure-valence state relationships enables control of the material properties. The authors performed investigations using a thermogravimetric apparatus with an electronic microbalance of type EM-5-3M, and using x-ray phase analysis of powders (DRON-1 diffractometer, CuK /SUB alpha/ -radiation). The authors also studied the kinetics of praseodymium oxidation with a thermogravimetric apparatus under isothermal conditions. Evaluation of the results with the equation of Kolmogorov, Erofeev, and Avraam indicates that the process is limited by the chemical oxidation of praseodymium and not by diffusion
Solid-Phase and Oscillating Solution Crystallization Behavior of (+)- and (-)-N-Methylephedrine.
Tulashie, Samuel Kofi; Polenske, Daniel; Seidel-Morgenstern, Andreas; Lorenz, Heike
2016-11-01
This work involves the study of the solid-phase and solution crystallization behavior of the N-methylephedrine enantiomers. A systematic investigation of the melt phase diagram of the enantiomeric N-methylephedrine system was performed considering polymorphism. Two monotropically related modifications of the enantiomer were found. Solubilities and the ternary solubility phase diagrams of N-methylephedrine enantiomers in 2 solvents [isopropanol:water, 1:3 (Vol) and (2R, 3R)-diethyl tartrate] were determined in the temperature ranges between 15°C and 25°C, and 25°C and 40°C, respectively. Preferential nucleation and crystallization experiments at higher supersaturation leading to an unusual oscillatory crystallization behavior as well as a successful preferential crystallization experiment at lower supersaturation are presented and discussed. Copyright © 2016. Published by Elsevier Inc.
Theoretical study on phase coexistence in ferroelectric solid solutions near the tricritical point
Energy Technology Data Exchange (ETDEWEB)
Lu, Xiaoyan, E-mail: luxy@hit.edu.cn, E-mail: dzk@psu.edu; Li, Hui [Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education, School of Civil Engineering, Harbin Institute of Technology, Harbin 150001 (China); Zheng, Limei [Condensed Matter Science and Technology Institute, Harbin Institute of Technology, Harbin 150001 (China); Cao, Wenwu [Condensed Matter Science and Technology Institute, Harbin Institute of Technology, Harbin 150001 (China); Department of Mathematics and Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States)
2015-04-07
Phase coexistence in ferroelectric solid solutions near the tricritical point has been theoretically analyzed by using the Landau-Devonshire theory. Results revealed that different phases having similar potential wells could coexist in a narrow composition range near the tricritical point in the classical Pb(Zr{sub 1−x}Ti{sub x})O{sub 3} system. The potential barrier between potential wells increases with the decrease of temperature. Coexisting phases or different domains of the same phase can produce adaptive strains to maintain atomic coherency at the interfaces or domain walls. Such compatibility strains have influence on the energy potential as well as the stability of relative phases, leading to the appearance of energetically unfavorable monoclinic phases. Those competing and coexisting phases also construct an easy phase transition path with small energy barrier in between, so that very small stimuli can produce large response in compositions near the morphotropic phase boundary, especially near the tricritical point.
Theoretical study on phase coexistence in ferroelectric solid solutions near the tricritical point
International Nuclear Information System (INIS)
Lu, Xiaoyan; Li, Hui; Zheng, Limei; Cao, Wenwu
2015-01-01
Phase coexistence in ferroelectric solid solutions near the tricritical point has been theoretically analyzed by using the Landau-Devonshire theory. Results revealed that different phases having similar potential wells could coexist in a narrow composition range near the tricritical point in the classical Pb(Zr 1−x Ti x )O 3 system. The potential barrier between potential wells increases with the decrease of temperature. Coexisting phases or different domains of the same phase can produce adaptive strains to maintain atomic coherency at the interfaces or domain walls. Such compatibility strains have influence on the energy potential as well as the stability of relative phases, leading to the appearance of energetically unfavorable monoclinic phases. Those competing and coexisting phases also construct an easy phase transition path with small energy barrier in between, so that very small stimuli can produce large response in compositions near the morphotropic phase boundary, especially near the tricritical point
Paramagnetic properties of the (U1-xTbx)Co2Ge2 solid solutions
International Nuclear Information System (INIS)
Kuznietz, Moshe; Pinto, Haim; Ettedgui, Hanania
1995-01-01
Polycrystalline (U 1-x Tb x )Co 2 Ge 2 solid solutions have the ThCr 2 Si 2 -type crystal structure and order antiferromagnetically. AC-susceptibility at 80-295 K yields paramagnetic Curie temperatures θ=-350±50, -15±5, -50±15, -12±5, and -80±5 K, and effective magnetic moments μ eff =4.5, 5.9, 7.3, 8.5, and 12.0 (±0.5)μ B , for samples with x=0, 0.25, 0.50, 0.75 and 1, respectively. The high μ eff values are related to occurrence of paramagnetic moments on U, Tb and Co, of which only U and Tb moments order magnetically. ((orig.))
Energy Technology Data Exchange (ETDEWEB)
Hollingsworth, Jennifer A. [Los Alamos National Laboratory; Palaniappan, Kumaranand [Los Alamos National Laboratory; Laocharoensuk, Rawiwan [National Science and Technology Center, Thailand; Smith, Nickolaus A. [Los Alamos National Laboratory; Dickerson, Robert M. [Los Alamos National Laboratory; Casson, Joanna L. [Los Alamos National Laboratory; Baldwin, Jon K. [Los Alamos National Laboratory
2012-06-07
Semiconductor nanowires (SC-NWs) have potential applications in diverse technologies from nanoelectronics and photonics to energy harvesting and storage due to their quantum-confined opto-electronic properties coupled with their highly anisotropic shape. Here, we explore new approaches to an important solution-based growth method known as solution-liquid-solid (SLS) growth. In SLS, molecular precursors are reacted in the presence of low-melting metal nanoparticles that serve as molten fluxes to catalyze the growth of the SC-NWs. The mechanism of growth is assumed to be similar to that of vapor-liquid-solid (VLS) growth, with the clear distinctions of being conducted in solution in the presence of coordinating ligands and at relatively lower temperatures (<300 C). The resultant SC-NWs are soluble in common organic solvents and solution processable, offering advantages such as simplified processing, scale-up, ultra-small diameters for quantum-confinement effects, and flexible choice of materials from group III-V to groups II-VI, IV-VI, as well as truly ternary I-III-VI semiconductors as we recently demonstrates. Despite these advantages of SLS growth, VLS offers several clear opportunities not allowed by conventional SLS. Namely, VLS allows sequential addition of precursors for facile synthesis of complex axial heterostructures. In addition, growth proceeds relatively slowly compared to SLS, allowing clear assessments of growth kinetics. In order to retain the materials and processing flexibility afforded by SLS, but add the elements of controlled growth afforded by VLS, we transformed SLS into a flow based method by adapting it to synthesis in a microfluidic system. By this new method - so-called 'flow-SLS' (FSLS) - we have now demonstrated unprecedented fabrication of multi-segmented SC-NWs, e.g., 8-segmented CdSe/ZnSe defined by either compositionally abrupt or alloyed interfaces as a function of growth conditions. In addition, we have studied growth
Investigating the effect of compression on solute transport through degrading municipal solid waste
Energy Technology Data Exchange (ETDEWEB)
Woodman, N.D., E-mail: n.d.woodman@soton.ac.uk; Rees-White, T.C.; Stringfellow, A.M.; Beaven, R.P.; Hudson, A.P.
2014-11-15
Highlights: • The influence of compression on MSW flushing was evaluated using 13 tracer tests. • Compression has little effect on solute diffusion times in MSW. • Lithium tracer was conservative in non-degrading waste but not in degrading waste. • Bromide tracer was conservative, but deuterium was not. - Abstract: The effect of applied compression on the nature of liquid flow and hence the movement of contaminants within municipal solid waste was examined by means of thirteen tracer tests conducted on five separate waste samples. The conservative nature of bromide, lithium and deuterium tracers was evaluated and linked to the presence of degradation in the sample. Lithium and deuterium tracers were non-conservative in the presence of degradation, whereas the bromide remained effectively conservative under all conditions. Solute diffusion times into and out of less mobile blocks of waste were compared for each test under the assumption of dominantly dual-porosity flow. Despite the fact that hydraulic conductivity changed strongly with applied stress, the block diffusion times were found to be much less sensitive to compression. A simple conceptual model, whereby flow is dominated by sub-parallel low permeability obstructions which define predominantly horizontally aligned less mobile zones, is able to explain this result. Compression tends to narrow the gap between the obstructions, but not significantly alter the horizontal length scale. Irrespective of knowledge of the true flow pattern, these results show that simple models of solute flushing from landfill which do not include depth dependent changes in solute transport parameters are justified.
Dissolution of britholites and monazite / brabantite solid solutions doped with actinides
International Nuclear Information System (INIS)
Du Fou De Kerdaniel, E.
2007-12-01
In the field of the radwaste storage in underground repository, several matrices were considered as promising ceramics for the specific immobilization of actinides. Two of them, britholites and monazite/ brabantite solid solution, have been considered during this work. In order to examine the dissolution mechanisms occurring at the solid liquid interface, several leaching experiments have been conducted on (Ln III PO 4 ), brabantite (Ca II An IV (PO 4 ) 2 : An = Th, U) and britholites (Ca 9 Nd 0.5 An 0.5 IV (PO 4 ) 4.5 (SiO 4 ) 1.5 F 2 : An = Th, U). Some steady experiments, performed in under saturation conditions for various pH and temperature conditions allowed to evaluate the long term behaviour of such matrices through their chemical durability. On the contrary, the thermodynamic equilibria were examined through the leaching experiments performed near the saturation conditions. By the way, various secondary phases, precipitated onto the surface of altered samples have been identified and characterized. Among them, the (Nd, Ca, Th) - rhabdophane, novelly prepared in over- saturation experiments for a thorium weight loading lower than 11 % appeared to be metastable. Indeed, it turns into TPHPH (Th 2 (PO 4 ) 2 HPO 4 .H 2 O) and Nd - rhabdophane (NdPO 4 .1/2H 2 O) when increasing leaching time. (author)
Energy Technology Data Exchange (ETDEWEB)
Bialy, Agata [Amminex Emissions Technology A/S, Gladsaxevej 363, 2860 Soeborg (Denmark); Jensen, Peter B. [Department of Energy Conversion and Storage, Technical University of Denmark, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Center for Atomic-scale Materials Design, Department of Physics, Technical University of Denmark, Fysikvej 311, DK-2800 Kgs. Lyngby (Denmark); Blanchard, Didier [Department of Energy Conversion and Storage, Technical University of Denmark, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Vegge, Tejs, E-mail: teve@dtu.dk [Department of Energy Conversion and Storage, Technical University of Denmark, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Quaade, Ulrich J., E-mail: ujq@amminex.com [Amminex Emissions Technology A/S, Gladsaxevej 363, 2860 Soeborg (Denmark)
2015-01-15
Metal halide ammines are very attractive materials for ammonia absorption and storage—applications where the practically accessible or usable gravimetric and volumetric storage densities are of critical importance. Here we present, that by combining advanced computational materials prediction with spray drying and in situ thermogravimetric and structural characterization, we synthesize a range of new, stable barium-strontium chloride solid solutions with superior ammonia storage densities. By tuning the barium/strontium ratio, different crystallographic phases and compositions can be obtained with different ammonia ab- and desorption properties. In particular it is shown, that in the molar range of 35–50% barium and 65–50% strontium, stable materials can be produced with a practically usable ammonia density (both volumetric and gravimetric) that is higher than any of the pure metal halides, and with a practically accessible volumetric ammonia densities in excess of 99% of liquid ammonia. - Graphical abstract: Thermal desorption curves of ammonia from Ba{sub x}Sr{sub (1−x)}Cl{sub 2} mixtures with x equal to 0.125, 0.25 and 0.5 and atomic structure of Sr(NH{sub 3}){sub 8}Cl{sub 2}. - Highlights: • Solid solutions of strontium and barium chloride were synthesized by spray drying. • Adjusting molar ratios led to different crystallographic phases and compositions. • Different molar ratios led to different ammonia ab-/desorption properties. • 35–50 mol% BaCl{sub 2} in SrCl{sub 2} yields higher ammonia density than any other metal halide. • DFT calculations can be used to predict properties of the mixtures.
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...
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)
Yan, Yan
2015-01-01
We study a new optimization scheme that generates smooth and robust solutions for Dirichlet velocity boundary control (DVBC) of conjugate heat transfer (CHT) processes. The solutions to the DVBC of the incompressible Navier-Stokes equations are typically nonsmooth, due to the regularity degradation of the boundary stress in the adjoint Navier-Stokes equations. This nonsmoothness is inherited by the solutions to the DVBC of CHT processes, since the CHT process couples the Navier-Stokes equations of fluid motion with the convection-diffusion equations of fluid-solid thermal interaction. Our objective in the CHT boundary control problem is to select optimally the fluid inflow profile that minimizes an objective function that involves the sum of the mismatch between the temperature distribution in the fluid system and a prescribed temperature profile and the cost of the control.Our strategy to resolve the nonsmoothness of the boundary control solution is based on two features, namely, the objective function with a regularization term on the gradient of the control profile on both the continuous and the discrete levels, and the optimization scheme with either explicit or implicit smoothing effects, such as the smoothed Steepest Descent and the Limited-memory Broyden-Fletcher-Goldfarb-Shanno (L-BFGS) methods. Our strategy to achieve the robustness of the solution process is based on combining the smoothed optimization scheme with the numerical continuation technique on the regularization parameters in the objective function. In the section of numerical studies, we present two suites of experiments. In the first one, we demonstrate the feasibility and effectiveness of our numerical schemes in recovering the boundary control profile of the standard case of a Poiseuille flow. In the second one, we illustrate the robustness of our optimization schemes via solving more challenging DVBC problems for both the channel flow and the flow past a square cylinder, which use initial
3He release characteristics of metal tritides and scandium--tritium solid solutions
International Nuclear Information System (INIS)
Perkins, W.G.; Kass, W.J.; Beavis, L.C.
1975-01-01
Tritides of such metals as scandium, titanium, and erbium are useful materials for determining the effects of helium accumulation in metallic solids, for example, CTR first wall materials. Such effects include lattice strain and gross deformation, as reported elsewhere, which are related to 3 He retention and ultimate release. Long term gas release studies have indicated that, during the early life of a metal ditritide, a large fraction of the 3 He is retained in the solid. At more advanced ages (2 to 4 years, depending on the parent metal), the 3 He release rate becomes comparable to the generation rate. Statistical analysis of the data indicates that the acceleration in 3 He release rate depends on accumulated 3 He concentration rather than strictly on age. 3 He outgassing results are presented for thin films of ScT 2 , TiT 2 , and ErT 2 , and the critical 3 He concentrations are discussed in terms of a percolation model. Phase transformations which occur on tritide formation cast some doubt on the validity of extrapolating results obtained for metal tritides to predictions regarding the accumulation of helium in metals. Scandium is unique among the early transition and rare-earth metals in that the metal exhibits a very high room temperature tritium solubility (T/Sc = 0.4) with no phase transformation. Indeed, even the lattice parameters of the hcp scandium lattice are only minimally changed by tritium solution, and we have succeeded in obtaining single crystal ScT 0 . 3 samples in two crystallographic orientations. Using a very sensitive technique, we have measured 3 He emission from both these samples, as well as from fine-grained thin film scandium-tritium solid solution samples (ScT 0 . 3 - 0 . 4 ). The fine-grained film samples release 3 He at 2 to 3 percent of the generation rate, while the emission rate from the single-crystal samples is approximately 0.05 percent of the generation rate, indicating a strong grain size effect
Crystalline structure and electrical properties of solid solutions YNixMn1-xO3
Directory of Open Access Journals (Sweden)
Moure, C.
1999-12-01
Full Text Available Solid solutions belonging to the Mn-rich region of the YNiXMn1-XO3 system have been studied. The powders were prepared by solid state reaction between the corresponding oxides. Sintered ceramics were obtained by firing at 1325-1350ºC. The incorporation of 20 atomic % Ni2+ to the Yttrium manganite induces the formation of a perovskite phase, with orthorhombic symmetry. Increase of the Ni amount leads to an increase of the orthorhombicity factor b/a, up to an amount of 50 atomic % Ni2+. Above this Ni amount, a biphasic system has been observed, with the presence of unreacted Y2O3. DC electrical conductivity measurements have shown semiconducting behaviour for all the solid solutions with perovskite-type structure. The room temperature conductivity increases with Ni until ~33 atomic % Ni, and then decreases. The 50/50 Ni/Mn composition has different values of conductivity and activation energy against those corresponding to samples with lower values of that ionic ratio. Small polaron hopping mechanism controls the conductivity in these ceramics. Results are discussed as a function of the Mn3+/Mn4+ ratio for each composition.Se han estudiado las soluciones sólidas correspondientes a la región rica en Mn del sistema YNiXMn1-XO3, entre 0 y 50 atomic % Ni. Los compuestos fueron preparados por reacción en estado sólido de los óxidos correspondientes. Se sinterizaron materiales cerámicos a 1325-1350ºC. Con cantidades de 20 atomic % Ni se produce la formación de una fase con estructura de perovskita, y simetría ortorrómbica. La distorsión ortorrómbica crece con el contenido de Ni. Por encima de 50 atomic % Ni, aparece Y2O3 sin reaccionar. Las soluciones sólidas muestran semiconducción con valores de σ que aumentan con el contenido de Ni hasta ~33 atomic %, para luego decrecer, hasta x=0.5. La composición 50/50 Ni/Mn muestra un comportamiento eléctrico algo diferente. Se discuten los resultados en función de la razón Mn3+/Mn4+ para cada
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.)
XAFS spectroscopic study of uranyl coordination in solids and aqueous solution
International Nuclear Information System (INIS)
Thompson, H.A.; Brown, G.E. Jr.; Parks, G.A.
1997-01-01
To evaluate the ability of X-ray absorption fine structure (XAFS) spectroscopy to elucidate the coordination environment of U 6+ at the solid-water interface, we conducted an in-depth analysis of experimental XAFS data from U 6+ solid and solution model compounds. Using the ab initio XAFS code FEFF6, we calculated phase-shift and amplitude functions for fitting experimental data. The code FEFF6 does a good job of reproducing experimental data and is particularly valuable for providing phase-shift and amplitude functions for neighboring atoms whose spectral contributions are difficult to isolate from experimental data because of overlap of Fourier transform features. In solid-phase model compounds at ambient temperature, we were able to fit spectral contributions from axial O (1.8 Angstrom), equatorial O (2.2-2.5 Angstrom), N (2.9 Angstrom), C (2.9 Angstrom), Si (3.2 Angstrom), P (3.6 Angstrom), distant 0 (4.3 Angstrom), and U (4.0, 4.3, 4.9, and 5.2 Angstrom) atoms. Contributions from N, C, Si, P, distant O, and distant U (4.9 and 5.2 Angstrom) are weak and therefore might go undetected in a sample of unknown composition. Lowering the temperature to 10 K extends detection of U neighbors to 7.0 Angstrom. The ability to detect these atoms suggests that XAFS might be capable of discerning inner-sphere U sorption at solid aluminosilicate-water interfaces. XAFS should definitely detect multinuclear U complexes and precipitates. Multiple-scattering paths are minor contributors to uranyl XAFS beyond k = 3 Angstrom -1 . Allowing shell-dependent disorder parameters (σ 2 ) to vary, we observed narrow ranges of σ 2 values for similar shells of neighboring atoms. Knowledge of these ranges is necessary to constrain the fit of XAFS spectra for unknowns. Finally, we found that structures reported in the literature for uranyl diacetate and rutherfordine are not completely correct. 50 refs., 6 figs., 2 tabs
Dispersion of dielectric permittivity and magnetic properties of solid solution PZT–PFT
Directory of Open Access Journals (Sweden)
Skulski Ryszard
2015-09-01
Full Text Available In this paper we present the results of investigations into ceramic samples of solid solution (1-x(PbZr0.53Ti0.47O3- x(PbFe0.5Ta0.503 (i.e. (1-xPZT-xPFT with x = 0.25, 0.35 and 0.45. We try to find the relation between the character of dielectric dispersion at various temperatures and the composition of this solution. We also describe the magnetic properties of investigated samples. With increasing the content of PFT also mass magnetization and mass susceptibility increase (i.e. magnetic properties are more pronounced at every temperature. The temperature dependences of mass magnetization and reciprocal of mass susceptibility have similar runs for all the compositions. However, our magnetic investigations exhibit weak antiferromagnetic ordering instead of the ferromagnetic one at room temperature. We can also say that up to room temperature any magnetic phase transition has not occurred. It may be a result of the conditions of the technological process during producing our PZT-PFT ceramics.
International Nuclear Information System (INIS)
Arnaud, B.
1986-06-01
We studied by T.E.M. the microstructures appearing in Nickel solid solution fatigued in push-pull between 0.4 Tm and 0.6 Tm (Tm=melting temperature), the maximum amplitude of stress was imposed: +- 100 MPa, three frequencies were used: 1.25 Hz, 2.5 Hz and 10 Hz. In Ni 6% at Ge the structure of dislocations evolves continuously with the number of cycles: homogeneous distribution of dislocations, cell structure, then development of sub-grains 5 times as big as the cell; these sub-grains are not stable, they break up into cells. This succession of structures suggests a cyclic evolution. The cavities appear for number of cycles greater than a threshold number depending on the temperature and the frequency. The cavities are not distributed uniformly, they are located in zone. According to the conditions of sollicitation, the shape (equiaxe of small stick) and the distribution (uniform, in band, in crown) of the cavities fluctuate. This cavitation exists equally in other materials (Ni 4% at Si, Ni). This intra-granular cavitation has been observed in the same domain of temperatures as the domain of swelling in the same material under bombardment with ions Ni + . Due to this similitude we searched for a segregation of solute (like the induced precipitation by irradiation) but this phenomenon did not occur with our experimental conditions [fr
A new variable temperature solution-solid interface scanning tunneling microscope.
Jahanbekam, Abdolreza; Mazur, Ursula; Hipps, K W
2014-10-01
We present a new solution-solid (SS) interface scanning tunneling microscope design that enables imaging at high temperatures with low thermal drift and with volatile solvents. In this new design, distinct from the conventional designs, the entire microscope is surrounded in a controlled-temperature and controlled-atmosphere chamber. This allows users to take measurements at high temperatures while minimizing thermal drift. By incorporating an open solution reservoir in the chamber, solvent evaporation from the sample is minimized; allowing users to use volatile solvents for temperature dependent studies at high temperatures. The new design enables the user to image at the SS interface with some volatile solvents for long periods of time (>24 h). An increase in the nonlinearity of the piezoelectric scanner in the lateral direction as a function of temperature is addressed. A temperature dependent study of cobalt(II) octaethylporphyrin (CoOEP) at the toluene/Au(111) interface has been performed with this instrument. It is demonstrated that the lattice parameters remain constant within experimental error from 24 °C to 75 °C. Similar quality images were obtained over the entire temperature range. We report the unit cell of CoOEP at the toluene/Au(111) interface (based on two molecules per unit cell) to be A = (1.36 ± 0.04) nm, B = (2.51 ± 0.04) nm, and α = 97° ± 2°.
Fabrication and Performance of All-Solid-State Chloride Sensors in Synthetic Concrete Pore Solutions
Directory of Open Access Journals (Sweden)
Hongwei Deng
2010-11-01
Full Text Available One type of all-solid-state chloride sensor was fabricated using a MnO2 electrode and a Ag/AgCl electrode. The potentiometric response of the sensor to chloride in synthetic concrete pore solutions was systematically studied, and the polarization performance was also evaluated. The results show a good linear relationship between the potential reading of the sensor and the logarithm of chloride activity (concentration ranges from 0.05 to 5.0 M, and the potential value remains stable with increasing immersion time. The existence of K+, Ca2+, Na+ and SO42− ions have little influence on the potentiometric response of the sensor to chloride, but the pH has a significant influence on the potential value of the sensor at low chloride concentration. The potential reading of the sensor increases linearly with the solution temperature over the range from 5 to 45 °C. Meanwhile, an excellent polarization behavior is proven by galvanostatic and potentiodynamic tests. All of the results reveal that the developed sensor has a great potential for monitoring chloride ions in concrete environments.
Gao, Xiaojian; Zhang, Jian; Yang, Yingzi; Deng, Hongwei
2010-01-01
One type of all-solid-state chloride sensor was fabricated using a MnO(2) electrode and a Ag/AgCl electrode. The potentiometric response of the sensor to chloride in synthetic concrete pore solutions was systematically studied, and the polarization performance was also evaluated. The results show a good linear relationship between the potential reading of the sensor and the logarithm of chloride activity (concentration ranges from 0.05 to 5.0 M), and the potential value remains stable with increasing immersion time. The existence of K(+), Ca(2+), Na(+) and SO(4) (2-) ions have little influence on the potentiometric response of the sensor to chloride, but the pH has a significant influence on the potential value of the sensor at low chloride concentration. The potential reading of the sensor increases linearly with the solution temperature over the range from 5 to 45 °C. Meanwhile, an excellent polarization behavior is proven by galvanostatic and potentiodynamic tests. All of the results reveal that the developed sensor has a great potential for monitoring chloride ions in concrete environments.
Energy Technology Data Exchange (ETDEWEB)
Lee, Ju hyeong; Park, Kwangheon; Kim, Tae hoon; Park, Hyoung gyu; Kim, Jisu [Kyunghee University, Yongin (Korea, Republic of); Song, Hyuk jin [Dongguk University, Gyeongju (Korea, Republic of); Lee, Chan ki; Kang, Do kyu; Jeong, Hyeon jun [UNIST, Ulsan (Korea, Republic of)
2016-10-15
In this experimental study program in Tohoku University, basic experiments were done by the participants. First one is the hydrogen reduction experiment of the mixture of UO{sub 2} and ZrO{sub 2}. Second one is to observe microscopic structure of solid solution of UO{sub 2} and ZrO{sub 2} using SEM/EDX and XRD system, simulated fuel debris. Third one is milking process of {sup 239}Np from {sup 243}Am by solvent extraction using Tri-n-Octylamine (TOA). Last one is solvent extraction in PUREX by the simulated mixed aqueous solution of U, {sup 85}Sr and {sup 239}Np which is represented minor actinide elements included in the spent nuclear fuel. Uranium is separated from aqueous phase to organic phase during solvent extraction procedure using TBP and dodecane. Also, neptunium can be extracted to organic phase as nitric acid concentration change. The extraction behavior of neptunium is different by oxidation state in aqueous phase. The behavior of neptunium is represented as a combined form of these oxidation states in experiment. Therefore, because the oxidation states of neptunium can be controlled by controlling the concentration of nitric acid, the extractability of neptunium can be controlled.
Galindo-Israel, V.; Imbriale, W.; Shogen, K.; Mittra, R.
1990-01-01
In obtaining solutions to the first-order nonlinear partial differential equations (PDEs) for synthesizing offset dual-shaped reflectors, it is found that previously observed computational problems can be avoided if the integration of the PDEs is started from an inner projected perimeter and integrated outward rather than starting from an outer projected perimeter and integrating inward. This procedure, however, introduces a new parameter, the main reflector inner perimeter radius p(o), when given a subreflector inner angle 0(o). Furthermore, a desired outer projected perimeter (e.g., a circle) is no longer guaranteed. Stability of the integration is maintained if some of the initial parameters are determined first from an approximate solution to the PDEs. A one-, two-, or three-parameter optimization algorithm can then be used to obtain a best set of parameters yielding a close fit to the desired projected outer rim. Good low cross-polarization mapping functions are also obtained. These methods are illustrated by synthesis of a high-gain offset-shaped Cassegrainian antenna and a low-noise offset-shaped Gregorian antenna.
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.
Yang, Lei; Ma, Liangong; Huang, Yuanding; Feyerabend, Frank; Blawert, Carsten; Höche, Daniel; Willumeit-Römer, Regine; Zhang, Erlin; Kainer, Karl Ulrich; Hort, Norbert
2017-06-01
Rare earth element Dy is one of the promising alloying elements for magnesium alloy as biodegradable implants. To understand the effect of Dy in solid solution on the degradation of Mg-Dy alloys in simulated physiological conditions, the present work studied the microstructure and degradation behavior of Mg-Dy alloys in cell culture medium. It is found the corrosion resistance enhances with the increase of Dy content in solid solution in Mg. This can be attributed to the formation of a relatively more corrosion resistant Dy-enriched film which decreases the anodic dissolution of Mg. Copyright © 2017 Elsevier B.V. All rights reserved.
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.
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
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.
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)
International Nuclear Information System (INIS)
Lee, Go-Eun; Kim, Il-Ho; Choi, Soon-Mok; Lim, Young-Soo; Seo, Won-Seon; Park, Jae-Soung; Yang, Seung-Ho
2014-01-01
Bi 2 Te 3-y Se y (y = 0.15 - 0.6) solid solutions were prepared by attrition milling and hot pressing. The lattice constants decreased with increasing Se content, indicating that the Se atoms were successfully substituted into the Te sites. All specimens exhibited n-type conduction, and their electrical resistivities increased slightly with increasing temperature. With increasing Se content, the Seebeck coefficients increased while the thermal conductivity decreased due to the increase in phonon scattering. The maximum figure of merit obtained was 0.63 at 440 K for the undoped Bi 2 Te 2.4 Se 0.6 solid solution.
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.
Grundland, A. M.; Lalague, L.
1996-04-01
This paper presents a new method of constructing, certain classes of solutions of a system of partial differential equations (PDEs) describing the non-stationary and isentropic flow for an ideal compressible fluid. A generalization of the symmetry reduction method to the case of partially-invariant solutions (PISs) has been formulated. We present a new algorithm for constructing PISs and discuss in detail the necessary conditions for the existence of non-reducible PISs. All these solutions have the defect structure 0305-4470/29/8/019/img1 and are computed from four-dimensional symmetric subalgebras. These theoretical considerations are illustrated by several examples. Finally, some new classes of invariant solutions obtained by the symmetry reduction method are included. These solutions represent central, conical, rational, spherical, cylindrical and non-scattering double waves.
Microstructural features of the La1−xCaxFeO3−δ solid solutions prepared via Pechini route
International Nuclear Information System (INIS)
Gerasimov, E.Yu.; Isupova, L.A.; Tsybulya, S.V.
2015-01-01
Highlights: • La 1−x Ca x FeO (3−δ) (0 ≤ x ≤ 0.7) perovskite were prepared by Pechini method. • Planar defects in direction (1 0 1) were observed in the perovskite surface. • α-Fe 2 O 3 particles (1–10 nm) on the surface of perovskite were revealed. • Amount of α-Fe 2 O 3 particles on the perovskite surface grew with rising x values. - Abstract: Solid solutions with La 1−x Ca x FeO 3−δ (0 ≤ x ≤ 0.7) perovskite-like structure prepared via Pechini route have been investigated by using high resolution transmission electron microscopy and X-ray diffraction. Extended planar defects lying in (1 0 1) crystallographic planes and α-Fe 2 O 3 nanoparticles on the surface of perovskite microcrystals are characteristic of the samples under investigation. It was found that testing of the samples in catalytic deep CH 4 oxidation process results in partial destruction of solid solutions with formation of planar defects in the bulk and α-Fe 2 O 3 particles on the surface
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
Numerical Simulation of Solid Combustion with a Robust Conjugate-Gradient Solution for Pressure
National Research Council Canada - National Science Library
Wang, Yi-Zun
2002-01-01
A Bi-Conjugate Gradient method (Bi-CGSTAB) is studied and tested for solid combustion in which the gas and solid phases are coupled by a set of conditions describing mass, momentum and heat transport across the interface...
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.
Virginia State Dept. of Waste Management, Richmond. Div. of Litter & Recycling.
This publication, the last in a series of seven for elementary schools, is an environmental education curriculum guide with a focus on waste management issues. It contains a unit of exercises selected for sixth grade students focusing on community solutions to solid waste pollution. Waste management activities included in this unit seek to…
Alvarez-Montan~o, Victor E.; Farías, Mario H.; Brown, Francisco; Mun~oz-Palma, Iliana C.; Cubillas, Fernando; Castillon-Barraza, Felipe F.
2017-01-01
A good understanding of ternary phase diagrams is required to advance and/or to reproduce experimental research in solid-state and materials chemistry. The aim of this paper is to describe the solutions to problems that appear when studying or determining ternary phase diagrams. A brief description of the principal features shown in phase diagrams…
About thermal properties of TIIn1-xNdxS2 (0≤X≤0.10) solid solutions
International Nuclear Information System (INIS)
Zarbaliev, M.M.; Agaeva, U.M.; Sardarova, N.S.
2013-01-01
This report is devoted to investigation of thermal expansion and thermal conductivity of TIIn 1 -xNd x S 2 (0≤X≤0.10) solid solutions, depending on the concentration and temperature at 80-450 K. The measurements were carried out on the thermal expansion of polycrystalline, and the thermal conductivity of single-crystal samples
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
Neutron diffraction studies on Ca1− xBaxZr4P6O24 solid solutions
Indian Academy of Sciences (India)
P6O24 compositions from combined Rietveld refinements of powder X-ray and neutron diffraction data. All the studied compositions crystallize in rhombohedral lattice (space group R-3 No. 148). A continuous solid solution is concluded from ...
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.
Vinogradova, Ekaterina V; Enakieva, Yulia Y; Nefedov, Sergey E; Birin, Kirill P; Tsivadze, Aslan Y; Gorbunova, Yulia G; Bessmertnykh Lemeune, Alla G; Stern, Christine; Guilard, Roger
2012-11-19
The first synthesis and self-organization of zinc β-phosphorylporphyrins in the solid state and in solution are reported. β-Dialkoxyphosphoryl-5,10,15,20-tetraphenylporphyrins and their Zn(II) complexes have been synthesized in good yields by using Pd- and Cu-mediated carbon-phosphorous bond-forming reactions. The Cu-mediated reaction allowed to prepare the mono-β-(dialkoxyphosphoryl)porphyrins 1 Zn-3 Zn starting from the β-bromo-substituted zinc porphyrinate ZnTPPBr (TPP = tetraphenylporphyrin) and dialkyl phosphites HP(O)(OR)(2) (R = Et, iPr, nBu). The derivatives 1 Zn-3 Zn were obtained in good yields by using one to three equivalents of CuI. When the reaction was carried out in the presence of catalytic amounts of palladium complexes in toluene, the desired zinc derivative 1 Zn was obtained in up to 72% yield. The use of a Pd-catalyzed C-P bond-forming reaction was further extended to the synthesis of β-poly(dialkoxyphosphoryl)porphyrins. An unprecedented one-pot sequence involving consecutive reduction and phosphorylation of H(2)TPPBr(4) led to the formation of a mixture of the 2,12- and 2,13-bis(dialkoxy)phosphorylporphyrins 5 H(2) and 6 H(2) in 81% total yield. According to the X-ray diffraction studies, 1 Zn and 3 Zn are partially overlapped cofacial dimers formed through the coordination of two Zn centers by two phosphoryl groups belonging to the adjacent molecules. The equilibrium between the monomeric and the dimeric species exists in solutions of 1 Zn and 3 Zn in weakly polar solvents according to spectroscopic data (UV/Vis absorption and NMR spectroscopy). The ratio of each form is dependent on the concentration, temperature, and traces of water or methanol. These features demonstrated that zinc β-phosphorylporphyrins can be regarded as new model compounds for the weakly coupled chlorophyll pair in the photosynthesis process. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Planet Patrol. An Environmental Unit on Solid Waste Solutions for Grades 4-6.
Procter and Gamble Educational Services, Cincinnati, OH.
This classroom unit was developed for use in grades 4-6 to help teach the concept of solid waste management. The teacher's guide provides an overview of the issue of solid waste disposal, a description of government, industry, and consumer roles in resolving the solid waste issue, and four lessons involving sanitary landfills, the reduction of…
Evolution of ion damage at 773K in Ni- containing concentrated solid-solution alloys
Shi, Shi; He, Mo-Rigen; Jin, Ke; Bei, Hongbin; Robertson, Ian M.
2018-04-01
Quantitative analysis of the impact of the compositional complexity in a series of Ni-containing concentrated solid-solution alloys, Ni, NiCo, NiFe, NiCoCr, NiCoFeCr, NiCoFeCrMn and NiCoFeCrPd, on the evolution of defects produced by 1 MeV Kr ion irradiation at 773 K is reported. The dynamics of the evolution of the damage structure during irradiation to a dose of 2 displacements per atom were observed directly by performing the ion irradiations in electron transparent foils in a transmission electron microscope coupled to an ion accelerator. The defect evolution was assessed through measurement of the defect density, defect size and fraction of perfect and Frank loops. These three parameters were dependent on the alloying element as well as the number of elements. The population of loops was sensitive to the ion dose and alloy composition as faulted Frank loops were observed to unfault to perfect loops with increasing ion dose. These dependences are explained in terms of the influence of each element on the lifetime of the displacement cascade as well as on defect formation and migration energies.
Cerium valence change in the solid solutions Ce(Rh1-xRux)Sn
International Nuclear Information System (INIS)
Niehaus, Oliver; Riecken, Jan F.; Winter, Florian; Poettgen, Rainer; Muenster Univ.; Abdala, Paula M.; Chevalier, Bernard
2013-01-01
The solid solutions Ce(Rh 1-x Ru x )Sn were investigated by means of susceptibility measurements, specific heat, electrical resistivity, X-ray absorption spectroscopy (XAS), and 119 Sn Moessbauer spectroscopy. Magnetic measurements as well as XAS data show a cerium valence change in dependence on the ruthenium content. Higher ruthenium content causes an increase from 3.22 to 3.45 at 300 K. Furthermore χ and χ -1 data indicate valence fluctuation for cerium as a function of temperature. For example, Ce(Rh 0.8 Ru 0.2 )Sn exhibits valence fluctuations between 3.42 and 3.32 in the temperature range of 10 to 300 K. This could be proven by using the interconfiguration fluctuation (ICF) model introduced by Sales and Wohlleben. Cerium valence change does not influence the tin atoms as proven by 119 Sn Moessbauer spectroscopy, but it influences the electrical properties. Ce(Rh 0.9 Ru 0.1 )Sn behaves like a typical valence fluctuating compound, and higher ruthenium content causes an increase of the metallic behavior. (orig.)
Radiation-induced segregation on defect clusters in single-phase concentrated solid-solution alloys
International Nuclear Information System (INIS)
Lu, Chenyang; Yang, Taini; Jin, Ke; Gao, Ning; Xiu, Pengyuan; Zhang, Yanwen; Gao, Fei; Bei, Hongbin; Weber, William J.; Sun, Kai; Dong, Yan; Wang, Lumin
2017-01-01
A group of single-phase concentrated solid-solution alloys (SP-CSAs), including NiFe, NiCoFe, NiCoFeCr, as well as a high entropy alloy NiCoFeCrMn, was irradiated with 3 MeV Ni"2"+ ions at 773 K to a fluence of 5 × 10"1"6 ions/cm"2 for the study of radiation response with increasing compositional complexity. Advanced transmission electron microscopy (TEM) with electron energy loss spectroscopy (EELS) was used to characterize the dislocation loop distribution and radiation-induced segregation (RIS) on defect clusters in the SP-CSAs. The results show that a higher fraction of faulted loops exists in the more compositionally complex alloys, which indicate that increasing compositional complexity can extend the incubation period and delay loop growth. The RIS behaviors of each element in the SP-CSAs were observed as follows: Ni and Co tend to enrich, but Cr, Fe and Mn prefer to deplete near the defect clusters. RIS level can be significantly suppressed by increasing compositional complexity due to the sluggish atom diffusion. According to molecular static (MS) simulations, “disk” like segregations may form near the faulted dislocation loops in the SP-CSAs. Segregated elements tend to distribute around the whole faulted loop as a disk rather than only around the edge of the loop.
International Nuclear Information System (INIS)
Dik, M.G.; Rybina, L.N.; Dubrovina, A.N.; Abdinov, D.Sh.
1988-01-01
Structure and depth of broken layer, occuring at electroerosion cutting along ingot samples axis of Bi 2 Te 3 -Bi 2 Se 3 , Bi 2 Te 3 -Sb 2 Te 3 systems solid solutions (obtained by methods of directed crystallization and extrusion), and equilibrium contact angle θ, adhesion effort A and contact resistance r c of these crystals contacts with eutectic alloy of Bi-Sn system are investigated. Depth and structure of the broken layer were determined by means of stage-by-stage scouring-etching and X-ray investigation of cutting surface. It is shown, that etching during ∼50 c in large-block material eliminates polycrystalline layer, lattice bendings, resulting in Laue spots asterism, but does not remove their fragmentation and wash-out. Slots wash-out reduces, while fragmentation remains even after continuous etching. Etching with duration from ∼50 c up to 30-40 min practically does not change the character of polycrystalline samples diffraction pattern
Energy Technology Data Exchange (ETDEWEB)
Unfried-Silgado, Jimy [Metals Characterization and Processing Laboratory, Brazilian Nanothecnology National Laboratory - CNPEM/ABTLuS, Caixa Postal 6192, CEP 13083-970, Campinas, Sao Paulo (Brazil); Universidade Estadual de Campinas UNICAMP, Faculdade de Engenharia Mecanica FEM, Campinas (Brazil); Universidad Autonoma del Caribe, Grupo IMTEF, Ingenieria Mecanica, Barranquilla (Colombia); Wu, Leonardo [Metals Characterization and Processing Laboratory, Brazilian Nanothecnology National Laboratory - CNPEM/ABTLuS, Caixa Postal 6192, CEP 13083-970, Campinas, Sao Paulo (Brazil); Furlan Ferreira, Fabio [Universidade Federal do ABC, Centro de Ciencias Naturais e Humanas (CCNH), Sao Paulo (Brazil); Mario Garzon, Carlos [Universidad Nacional de Colombia, Departamento de Fisica, Bogota (Colombia); Ramirez, Antonio J, E-mail: antonio.ramirez@lnnano.org.br [Metals Characterization and Processing Laboratory, Brazilian Nanothecnology National Laboratory - CNPEM/ABTLuS, Caixa Postal 6192, CEP 13083-970, Campinas, Sao Paulo (Brazil)
2012-12-15
The stacking fault energy (SFE) in a set of experimental Ni-Cr-Fe alloys was determined using line profile analysis on synchrotron X-ray diffraction measurements. The methodology used here is supported by the Warren-Averbach calculations and the relationships among the stacking fault probability ({alpha}) and the mean-square microstrain (<{epsilon}{sup 2}{sub L}>). These parameters were obtained experimentally from cold-worked and annealed specimens extracted from the set of studied Ni-alloys. The obtained results show that the SFE in these alloys is strongly influenced by the kind and quantity of addition elements. Different effects due to the action of carbide-forming elements and the solid solution hardening elements on the SFE are discussed here. The simultaneous addition of Nb, Hf, and, Mo, in the studied Ni-Cr-Fe alloys have generated the stronger decreasing of the SFE. The relationships between SFE and the contributions on electronic structure from each element of additions were established.
Kiani, Armin; Dastafkan, Kamran; Obeydavi, Ali; Rahimi, Mohammad
2017-12-01
Nanocrystalline solid solutions consisting of un-doped and gadolinium doped zinc oxide nanorods were fabricated by a modified sol-gel process utilizing combined ultrasonic-microwave irradiations. Polyvinylpyrrolidone, diethylene glycol, and triethylenetetramine respectively as capping, structure directing, and complexing agents were used under ultrasound dynamic aging and microwave heating to obtain crystalline nanorods. Crystalline phase monitoring, lattice parameters and variation, morphology and shape, elemental analysis, functional groups, reducibility, and the oxidation state of emerged species were examined by PXRD, FESEM, TEM, EDX, FTIR, micro Raman, H2-TPR, and EPR techniques. Results have verified that irradiation mechanism of gelation and crystallization reduces the reaction time, augments the crystal quality, and formation of hexagonal close pack structure of Wurtzite morphology. Besides, dissolution of gadolinium within host lattice involves lattice deformation, unit cell distortion, and angular position variation. Structure related shape and growth along with compositional purity were observed through microscopic and spectroscopic surveys. Furthermore, TPR and EPR studies elucidated more detailed behavior upon exposure to the exerted irradiations and subsequent air-annealing including the formed oxidation states and electron trapping centers, presence of gadolinium, zinc, and oxygen disarrays and defects, as well as alteration in the host unit cell via gadolinium addition.
Bioadsorption of a reactive dye from aqueous solution by municipal solid waste
Directory of Open Access Journals (Sweden)
Abdelkader Berrazoum
2015-09-01
Full Text Available The biosorbent was obtained from municipal solid waste (MSW of the Mostaganem city. Before use the MSW was dried in air for three days and washed several times. The sorption of yellow procion reactive dye MX-3R onto biomass from aqueous solution was investigated as function of pH, contact time and temperature. The adsorption capacity of MX-3R was 45.84 mg/g at pH 2–3 and room temperature. MX-3R adsorption decreases with increasing temperature. The Langmuir, Freundlich and Langmuir–Freundlich adsorption models were applied to describe the related isotherms. Langmuir–Freundlich equation has shown the best fitting with the experimental data. The pseudo first-order, pseudo second-order and intra-particle diffusion kinetic models were used to describe the kinetic sorption. The results clearly showed that the adsorption of MX-3R onto biosorbent followed the pseudo second-order model. The enthalpy (ΔH°, entropy (ΔS° and Gibbs free energy (ΔG° changes of adsorption were calculated. The results indicated that the adsorption of MX-3R occurs spontaneously as an exothermic process.
High-temperature superconductivity in solid solutions based on mixed yttrium and barium cuprate
International Nuclear Information System (INIS)
Bazuev, G.V.; Kirsanov, N.A.; Makarova, O.V.; Zubkov, V.G.; Shveikin, G.P.
1990-01-01
The discovery of high-temperature superconductivity (T c = 30-40 K) in mixed lanthanum and alkaline earth cuprates La 2-x M x CuO 4 , where M = Ba and Ca (1-3) stimulated an extensive search for new superconducting phases based on mixed oxides of these elements. The superconducting transition temperature T c in LnBa 2 Cu 3 O 7-z phases is practically independent of the REE and lies between 90-96 K. The crystal structure of superconducting YBa 2 Cu 3 O 7-z is similar to perovskite, has orthorhombic symmetry (4,5), and is related to the lanthanum barium cuprite tetragonal defect structure La 3 Ba 3 Cu 6 O 14.1 (8). A study of possible solid solutions (SS) based on YBa 2 Cu 3 O 7-z through iso- or heterovalent substitution for Y 3+ and Ba 2+ and of their electrical properties seems warranted. In the present work, the authors report the synthesis, x-ray diffraction study, and specific electric resistivity of SS Y 1-x M x (Ba 1-y M y ') 2 Cu 3 O 7-z , where M = La, Lu, Sc, In, K, Zr, and Ce and M' = Ca, Sr, Mg, K, and La
Bayliss, Ryan D.; Cook, Stuart N.; Scanlon, David O.; Fearn, Sarah; Cabana, Jordi; Greaves, Colin; Kilner, John A.; Skinner, Stephen J.
2014-01-01
© the Partner Organisations 2014. Recent reports of remarkably high oxide ion conduction in a new family of strontium silicates have been challenged. It has recently been demonstrated that, in the nominally potassium substituted strontium germanium silicate material, the dominant charge carrier was not the oxygen ion, and furthermore that the material was not single phase (R. D. Bayliss et. al., Energy Environ. Sci., 2014, DOI: 10.1039/c4ee00734d). In this work we re-investigate the sodium-doped strontium silicate material that was reported to exhibit the highest oxide ion conductivity in the solid solution, nominally Sr0.55Na0.45SiO2.775. The results show lower levels of total conductivity than previously reported and sub-micron elemental mapping demonstrates, in a similar manner to that reported for the Sr0.8K0.2Si0.5Ge0.5O2.9 composition, an inhomogeneous chemical distribution correlating with a multiphase material. It is also shown that the conductivity is not related to protonic mobility. A density functional theory computational approach provides a theoretical justification for these new results, related to the high energetic costs associated with oxygen vacancy formation. This journal is
Bechtel, Jonathon S.; Van der Ven, Anton
2018-04-01
Halide substitution gives rise to a tunable band gap as a function of composition in halide perovskite materials. However, photoinduced phase segregation, observed at room temperature in mixed halide A Pb (IxBr1-x) 3 systems, limits open circuit voltages and decreases photovoltaic device efficiencies. We investigate equilibrium phase stability of orthorhombic P n m a γ -phase CsM (XxY1-x) 3 perovskites where M is Pb or Sn, and X and Y are Br, Cl, or I. Finite-temperature phase diagrams are constructed using a cluster expansion effective Hamiltonian parameterized from first-principles density-functional-theory calculations. Solid solution phases for CsM (IxBr1-x) 3 and CsM (BrxCl1-x) 3 are predicted to be stable well below room temperature while CsM (IxCl1-x) 3 systems have miscibility gaps that extend above 400 K. The height of the miscibility gap correlates with the difference in volume between end members. Also layered ground states are found on the convex hull at x =2 /3 for CsSnBr2Cl ,CsPbI2Br , and CsPbBrCl2. The impact of these ground states on the finite temperature phase diagram is discussed in the context of the experimentally observed photoinduced phase segregation.
International Nuclear Information System (INIS)
Al-Ghouti, Mohammad A.; Li, Juiki; Salamh, Yousef; Al-Laqtah, Nasir; Walker, Gavin; Ahmad, Mohammad N.M.
2010-01-01
A potential usefulness of raw date pits as an inexpensive solid adsorbent for methylene blue (MB), copper ion (Cu 2+ ), and cadmium ion (Cd 2+ ) has been demonstrated in this work. This work was conducted to provide fundamental information from the study of equilibrium adsorption isotherms and to investigate the adsorption mechanisms in the adsorption of MB, Cu 2+ , and Cd 2+ onto raw date pits. The fit of two models, namely Langmuir and Freundlich models, to experimental data obtained from the adsorption isotherms was checked. The adsorption capacities of the raw date pits towards MB and both Cu 2+ and Cd 2+ ions obtained from Langmuir and Freundlich models were found to be 277.8, 35.9, and 39.5 mg g -1 , respectively. Surface functional groups on the raw date pits surface substantially influence the adsorption characteristics of MB, Cu 2+ , and Cd 2+ onto the raw date pits. The Fourier transform infrared spectroscopy (FTIR) studies show clear differences in both absorbances and shapes of the bands and in their locations before and after solute adsorption. Two mechanisms were observed for MB adsorption, hydrogen bonding and electrostatic attraction, while other mechanisms were observed for Cu 2+ and Cd 2+ . For Cu 2+ , binding two cellulose/lignin units together is the predominant mechanism. For Cd 2+ , the predominant mechanism is by binding itself using two hydroxyl groups in the cellulose/lignin unit.
A Unified Physical Model for Creep and Hot Working of Al-Mg Solid Solution Alloys
Directory of Open Access Journals (Sweden)
Stefano Spigarelli
2017-12-01
Full Text Available The description of the dependence of steady-state creep rate on applied stress and temperature is almost invariably based on the Norton equation or on derived power-law relationships. In hot working, the Norton equation does not work, and is therefore usually replaced with the Garofalo (sinh equation. Both of these equations are phenomenological in nature and can be seldom unambiguously related to microstructural parameters, such as dislocation density, although early efforts in this sense led to the introduction of the “natural power law” with exponent 3. In an attempt to overcome this deficiency, a recent model with sound physical basis has been successfully used to describe the creep response of fcc metals, such as copper. The main advantage of this model is that it does not require any data fitting to predict the strain rate dependence on applied stress and temperature, which is a particularly attractive peculiarity when studying the hot workability of metals. Thus, the model, properly modified to take into account solid solution strengthening effects, has been here applied to the study of the creep and hot-working of simple Al-Mg single phase alloys. The model demonstrated an excellent accuracy in describing both creep and hot working regimes, still maintaining its most important feature, that is, it does not require any fitting of the experimental data.
Carbonation of municipal solid waste incineration electrostatic precipitator fly ashes in solution.
De Boom, Aurore; Aubert, Jean-Emmanuel; Degrez, Marc
2014-05-01
Carbonation was applied to a Pb- and Zn-contaminated fraction of municipal solid waste incineration electrofilter fly ashes in order to reduce heavy metal leaching. Carbonation tests were performed in solution, by Na2CO3 addition or CO2 bubbling, and were compared with washing (with water only). The injection of CO2 during the washing did not modify the mineralogy, but the addition of Na2CO3 induced the reaction with anhydrite, forming calcite. Microprobe analyses showed that Pb and Zn contamination was rather diffuse and that the various treatments had no effect on Pb and Zn speciation in the residues. The leaching tests indicated that carbonation using Na2CO3 was successful because it gave a residue that could be considered as non-hazardous material. With CO2 bubbling, Pb and Zn leaching was strongly decreased compared with material washed with water alone, but the amount of chromium extracted became higher than the non-hazardous waste limits for landfilling.
Bayliss, Ryan D.
2014-09-24
© the Partner Organisations 2014. Recent reports of remarkably high oxide ion conduction in a new family of strontium silicates have been challenged. It has recently been demonstrated that, in the nominally potassium substituted strontium germanium silicate material, the dominant charge carrier was not the oxygen ion, and furthermore that the material was not single phase (R. D. Bayliss et. al., Energy Environ. Sci., 2014, DOI: 10.1039/c4ee00734d). In this work we re-investigate the sodium-doped strontium silicate material that was reported to exhibit the highest oxide ion conductivity in the solid solution, nominally Sr0.55Na0.45SiO2.775. The results show lower levels of total conductivity than previously reported and sub-micron elemental mapping demonstrates, in a similar manner to that reported for the Sr0.8K0.2Si0.5Ge0.5O2.9 composition, an inhomogeneous chemical distribution correlating with a multiphase material. It is also shown that the conductivity is not related to protonic mobility. A density functional theory computational approach provides a theoretical justification for these new results, related to the high energetic costs associated with oxygen vacancy formation. This journal is
International Nuclear Information System (INIS)
Grigor'eva, L.I.; Ignat'eva, I.V.; Kalinskaya, T.V.
1985-01-01
Mixed sulfides (Cd, Mn)S and (Cd, Mn, Zn)S with manganese sulfide content upto 50 mol% are synthesized. The possibility of preparing solid solutions both on the basis of silfides (Cd, Mn)S and in the ternary system (Cd, Mn, Zn)S with the temperature of polymorphic transformation of a cubic structure into a hexagonal one, being lower (500 deg C) than in the absence of MnS, is shown by the X-ray diffraction method. The colour analysis of the pigment specimens obtained has shown that the quantity of oxidized manganese compounds, producing no effect of the system colour, should not exceed 0.05 mol% on conversion to MnS. Among the mixed specimens (Cd, Mn)S the brightest colour background is obtained for specimens calcinated at 500-550 deg C. The mixed sulfide of the composition 0.77CdSx0.15MnSx0.08ZnS, calcinated at 500 deg C, gives a pigment corresponding to a commercial one by colour
Mees, Maarten; Haladjova, Emi; Momekova, Denitsa; Momekov, Georgi; Shestakova, Pavletta S; Tsvetanov, Christo B; Hoogenboom, Richard; Rangelov, Stanislav
2016-11-14
Random copolymers of n-propyl-2-oxazoline and ethylenimine (PPrOx-PEI) were prepared by partial acidic hydrolysis of poly(n-propyl-2-oxazoline) (PPrOx). Dynamic and electrophoretic light scattering and diffusion-ordered NMR spectroscopy were utilized to investigate aqueous solution properties of the copolymers. Above a specific cloud point temperature, well-defined nanoparticles were formed. The latter consisted of a core composed predominantly of PPrOx and a thin positively charged shell from PEI moieties that mediated formation of polyplexes with DNA. The polyplexes were prepared at 65 °C at varying N/P (amine-to-phosphate groups) ratios. They underwent structural changes upon temperature variations 65-25-37 °C depending on N/P. At N/P < 2, the polyplex particles underwent minor changes because of formation of a surface layer of DNA that acted as a barrier and prevented swelling and disintegration of the initial particles. Dramatic rearrangements at N/P ≥ 2 resulting in large swollen microgel particles were overcome by coating of the polyplex particles with a cross-linked polymeric shell. The shell retained the colloidal stability and preserved the physicochemical parameters of the initial polyplex particles while it reduced the high surface potential values. Progressive loss of cytotoxicity upon complexation with DNA and coating of polyplex particles was displayed.
Sun, Shuyu
2012-09-01
In this paper we introduce a new technique for the numerical solution of the various partial differential equations governing flow and transport phenomena in porous media. This method is proposed to be used in high level programming languages like MATLAB, Python, etc., which show to be more efficient for certain mathematical operations than for others. The proposed technique utilizes those operations in which these programming languages are efficient the most and keeps away as much as possible from those inefficient, time-consuming operations. In particular, this technique is based on the minimization of using multiple indices looping operations by reshaping the unknown variables into one-dimensional column vectors and performing the numerical operations using shifting matrices. The cell-centered information as well as the face-centered information are shifted to the adjacent face-center and cell-center, respectively. This enables the difference equations to be done for all the cells at once using matrix operations rather than within loops. Furthermore, for results post-processing, the face-center information can further be mapped to the physical grid nodes for contour plotting and stream lines constructions. In this work we apply this technique to flow and transport phenomena in porous media. © 2012 Elsevier Ltd.
International Nuclear Information System (INIS)
Moraes, M.A.P.V. de; Pugliesi, R.; Khouri, M.T.F.C.
1985-11-01
The solid state nuclear track detectors technique has been used for determination of boron in aqueous solutions, using a filtered neutron beam. The particles tracks from the 10 B(n,α)Li 7 reaction were registered in the CR-39 film, chemically etched in a (30%) KOH solution 70 0 C during 90 minutes. The obtained results showed the usefulness of this technique for boron determination in the ppm range. The inferior detectable limit was 9 ppm. The combined track registration efficiency factor K has been evaluated in the solutions, for the CR-39 detector and its values is K= (4,60 - + 0,06). 10 -4 cm. (Author) [pt
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
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.
Vasileiou, Zoe; Barlos, Kostas; Gatos, Dimitrios
2009-12-01
The RING finger domain of the Mdm2, located at the C-terminus of the protein, is necessary for regulation of p53, a tumor suppressor protein. The 48-residues long Mdm2 peptide is an important target for studying its interaction with small anticancer drug candidates. For the chemical synthesis of the Mdm2 RING finger domain, the fragment condensation on solid-phase and the fragment condensation in solution were studied. The latter method was performed using either protected or free peptides at the C-terminus as the amino component. Best results were achieved using solution condensation where the N-component was applied with the C-terminal carboxyl group left unprotected. The developed method is well suited for large-scale synthesis of Mdm2 RING finger domain, combining the advantages of both solid-phase and solution synthesis. (c) 2009 European Peptide Society and John Wiley & Sons, Ltd.
Dwivedi, Akansha
Two new bismuth and lead oxide based perovskite ternary solid solutions, namely xBi(Zn1/2Ti1/2)O3-yPbZrO3-zPbTiO3 [xBZT-yPZ-zPT] and xBi(Mg1/2Ti1/2)O3-yBi(Zn 1/2Ti1/2)O3-zPbTiO3 [xBMT-yBZT-zPT] have been developed and their structural and electrical properties have been determined. Various characterization techniques such as X-ray diffraction, calorimetery, electron microscopy, dielectric and piezoelectric measurements have been performed to determine the details of the phase diagram, crystal structure, and domain structure. The selection of these materials is based on the hypothesis that the presence of BZT-PT (Case I ferroelectric (FE)) will increase the transition temperature of MPB systems BMT-PT (Case II FE), and PZ-PT (Case III FE), and subsequently a MPB will be observed in the ternary phase diagrams. The Case I, II, and III classification has been outlined by Stringer et al., is on the basis of the transition temperatures (TC) behavior with composition in the Bi and Pb oxide based binary systems. Several pseudobinary lines have been investigated across the xBZT-yPZ-zPT ternary phase diagram which exhibit varied TC behavior with composition, showing both Case I- and Case III-like TC trends in different regions. A MPB between rhombohedral to tetragonal phases has been located on a pseudobinary line 0.1BZT-0.9[xPT-(1-x)PZ]. Compositions near MPB exhibit mainly soft PZT-like properties with the TC around 60°C lower than the unmodified PZT near its MPB. Electrical properties are reported for the MPB composition, TC = 325°C, Pr = 35 microC/cm2, d33 = 300 pC/N and kP =0.45. Rhombohedral compositions show diffuse phase transition with small frequency dispersion, similar to relaxors. Two transition peaks in the permittivity as well as in the latent heat has been observed in some compositions near the BZT-PT binary. This leads to the speculation for the existence of miscibility gap in the solid solutions in these regions. Transmission electron microscopy (TEM
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.
Ionic conductivity of LISICON solid solutions, Li 2+2 xZn 1- xGeO 4
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.
Calculation of thermodynamic equilibrium between bcc disordered solid solutions U and Mo
International Nuclear Information System (INIS)
Alonso, Paula R.; Rubiolo, Gerardo H.
2003-01-01
There is actually an interest to develop a new fuel with higher density for research reactors. Fuel plates would be obtained by dispersion, a method that requires both a very dense fuel dispersant (>15.0 g U/cm 3 ) and a very high volume loading of the dispersant (>55%). Dispersants based in gamma (BCC) stabilized uranium alloys are being investigated, as they are able to reach uranium densities of 17.0 g U/cm 3 . Among them, we focus in U(Mo) bcc solid solutions with the addition of ternary elements to stabilize gamma phase. Transition metals, 4d and 5d, of groups VII and VIII are good candidates for the ternary alloy U - Mo - X. Their relative power to stabilize gamma phase seems to be in close relation with bonding energies between atoms in the alloy. A first approach to the calculation of these energies has been performed by the semi empiric method of Miedema where only bonds between pairs are considered, neglecting ternary and quaternary bonds. There is also a lack of information concerning solubilities of the ternary elements in the ternary cubic phase. In this work we aim to calculate bonding energies between atoms in the alloy using a cluster expansion of the formation energy (T=0 K) of a series of bcc ordered compounds in the systems U-Mo-X. Then the calculation of the equilibrium phase diagram by the Cluster Variation Method will be done (CVM). We show here the first part of the investigation devoted to calculation of phases equilibria in the U Mo system Formation energies of the ordered compounds were obtained by the first principles methods TB-LMTO-ASA and FP-LAPW. Another set of bonding energies was calculated in order to fit the known experimental diagram and new formation energies for the ordered compounds were derived from them. Discrepancies between both sets are discussed. (author)
Quantum statistical effects in the mass transport of interstitial solutes in a crystalline solid
Woo, C. H.; Wen, Haohua
2017-09-01
The impact of quantum statistics on the many-body dynamics of a crystalline solid at finite temperatures containing an interstitial solute atom (ISA) is investigated. The Mori-Zwanzig theory allows the many-body dynamics of the crystal to be formulated and solved analytically within a pseudo-one-particle approach using the Langevin equation with a quantum fluctuation-dissipation relation (FDR) based on the Debye model. At the same time, the many-body dynamics is also directly solved numerically via the molecular dynamics approach with a Langevin heat bath based on the quantum FDR. Both the analytical and numerical results consistently show that below the Debye temperature of the host lattice, quantum statistics significantly impacts the ISA transport properties, resulting in major departures from both the Arrhenius law of diffusion and the Einstein-Smoluchowski relation between the mobility and diffusivity. Indeed, we found that below one-third of the Debye temperature, effects of vibrations on the quantum mobility and diffusivity are both orders-of-magnitude larger and practically temperature independent. We have shown that both effects have their physical origin in the athermal lattice vibrations derived from the phonon ground state. The foregoing theory is tested in quantum molecular dynamics calculation of mobility and diffusivity of interstitial helium in bcc W. In this case, the Arrhenius law is only valid in a narrow range between ˜300 and ˜700 K. The diffusivity becomes temperature independent on the low-temperature side while increasing linearly with temperature on the high-temperature side.
International Nuclear Information System (INIS)
Ruan, Ying; Li, Liuhui; Gu, Qianqian; Zhou, Kai; Yan, Na; Wei, Bingbo
2016-01-01
Highlights: • Length change difference between rapidly and slowly solidified Co-Si alloy occurs at high temperature. • Generally CTE increases with an increasing Si content. • The thermal diffusion abilities are CoSi 2 > Co 95 Si 5 > Co 90 Si 10 > Co 2 Si > CoSi if T exceeds 565 K. • All the CTE and thermal diffusivity variations with T satisfy linear or polynomial relations. - Abstract: The thermal expansion of Co-Si solid solutions and intermetallic compounds was measured via dilatometric method, compared with the results of first-principles calculations, and their thermal diffusivities were investigated using laser flash method. The length changes of rapidly solidified Co-Si alloys are larger than those of slowly solidified alloys when temperature increases to around 1000 K due to the more competitive atom motion. The coefficient of thermal expansion (α) of Co-Si alloy increases with an increasing Si content, except that the coefficient of thermal expansion of Co 95 Si 5 influenced by both metastable structure and allotropic transformation is lower than that of Co 90 Si 10 at a higher temperature. The thermal expansion abilities of Co-Si intermetallic compounds satisfy the relationship of Co 2 Si > CoSi > CoSi 2 , and the differences of the coefficients of thermal expansion between them increase with the rise of temperature. The thermal diffusivity of CoSi 2 is evidently larger than the values of other Co-Si alloys. If temperature exceeds 565 K, their thermal diffusion abilities are CoSi 2 > Co 95 Si 5 > Co 90 Si 10 > Co 2 Si > CoSi. All the coefficient of thermal expansion and thermal diffusivity variations with temperature satisfy linear or polynomial relations.
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
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)
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.
Energy Technology Data Exchange (ETDEWEB)
Chen, Daqin, E-mail: dqchen@hdu.edu.cn; Xu, Wei; Zhou, Yang; Chen, Yan, E-mail: chenyan@hdu.edu.cn
2016-08-15
Lanthanide doped Ba{sub 1-x}Sr{sub x}TiO{sub 3} (x = 0–1) solid-solution phosphors were successfully prepared by a conventional solid-state reaction. Using Eu{sup 3+} dopants as the structural probe, the variation of {sup 5}D{sub 0} → {sup 7}F{sub 2}/{sup 5}D{sub 0} → {sup 7}F{sub 1} emission intensity ratio with increase of Eu{sup 3+} content and the excitation-wavelength-dependent luminescence in the Ba{sub 1-x}Sr{sub x}TiO{sub 3} sample were demonstrated to be originated from the different emission behaviors of Eu{sup 3+} in Ba{sup 2+}/Sr{sup 2+} site and Ti{sup 4+} site. Furthermore, upconversion luminescence for the Yb{sup 3+}/Er{sup 3+} co-doped Ba{sub 1-x}Sr{sub x}TiO{sub 3} samples were investigated, and it was found that the emission intensity of Yb{sup 3+}/Er{sup 3+}: Ba{sub 0.5}Sr{sub 0.5}TiO{sub 3} phosphor was about 5 and 2 times as high as those of Yb{sup 3+}/Er{sup 3+}: BaTiO{sub 3} and Yb{sup 3+}/Er{sup 3+}: SrTiO{sub 3} ones. Using the investigated Yb{sup 3+}/Er{sup 3+}: Ba{sub 0.5}Sr{sub 0.5}TiO{sub 3} solid-solution as the optical thermometric medium, the temperature sensitivity was determined to be 0.76% K{sup −1} at the temperature of 610 K based on the temperature-dependent fluorescence intensity ratio of the thermally coupled {sup 2}H{sub 11/2} and {sup 4}S{sub 3/2} emitting-states of Er{sup 3+}. - Highlights: • Lanthanide doped Ba{sub 1-x}Sr{sub x}TiO{sub 3} (x = 0–1) solid-solutions were fabricated. • Excitation-wavelength-dependent Eu{sup 3+} emissions were recorded. • Enhanced Er{sup 3+} luminescence was realized by partial substitution of Ba{sup 2+} by Sr{sup 2+}. • T-sensitive emissions of two Er{sup 3+} thermally coupled states were observed. • The upconversion phosphor exhibited a high sensitivity of 0.76% K{sup −1}.
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
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
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).
DEFF Research Database (Denmark)
Panagiotou, Gianni; Granouillet, P.; Olsson, Lisbeth
2006-01-01
The production of a battery of arabinoxylan-degrading enzymes by the fungus Penicillium brasilianum grown on brewer's spent grain (BSG) under solid-state fermentation was investigated. Initial moisture content, initial pH, temperature, and nitrogen source content were optimized to achieve maximum...
Directory of Open Access Journals (Sweden)
XIAOLEI SU
2014-03-01
Full Text Available SiC(Fe solid solution powders were synthesized by sol–gel method under different reaction time, using methyltriethoxysilane as the silicon and carbon source and analytic ferric chloride as the dopant, respectively. The synthesized powders have been characterized by XRD, SEM and Raman spectra. Results show that the lattice constant decreases with increasing reaction time. The electric permittivities of SiC samples were determined in the frequency range of 8.2 ~ 12.4 GHz. Results show that the permittivity of SiC decreases with increasing reaction time. The SiC(Fe solid solution powder with reaction time of 4 h with 2 mm thickness exhibit the best microwave absorption property in X-band range (8.2 - 12.4 GHz. The microwave absorption mechanism has been discussed.
High-temperature thermoelectric properties of the β-As2−xBixTe3 solid solution
Directory of Open Access Journals (Sweden)
J.-B. Vaney
2016-10-01
Full Text Available Bi2Te3-based compounds are a well-known class of outstanding thermoelectric materials. β-As2Te3, another member of this family, exhibits promising thermoelectric properties around 400 K when appropriately doped. Herein, we investigate the high-temperature thermoelectric properties of the β-As2−xBixTe3 solid solution. Powder X-ray diffraction and scanning electron microscopy experiments showed that a solid solution only exists up to x = 0.035. We found that substituting Bi for As has a beneficial influence on the thermopower, which, combined with extremely low thermal conductivity values, results in a maximum ZT value of 0.7 at 423 K for x = 0.017 perpendicular to the pressing direction.
International Nuclear Information System (INIS)
Fedotov, V.K.; Antonov, V.E.; Kolesnikov, A.I.; Kornell, K.; Vipf, G.; Grosse, G.; Vagner, F.Eh.; Sikolenko, V.V.; Sumin, V.V.; )
1997-01-01
The FCC-lattice of the solid solution α-MnH 0.073 with the mass of 8.45 g is investigated by the neutron diffraction method and the inelastic neutron scattering technique. The neutron diffraction measurements are made by the diffractometer D1B with pyrographite monochromator and the high-resolution Fourier diffractometer HRFD at 300 K. The study of the inelastic incoherent neutron scattering is carried out by means of the inverse geometry spectrometer KDSOG-M at 90 K. The comparative analysis of α-MnH 0.073 and α-Mn spectra is fulfilled for the more correct separation of effects of hydrogen introduction. It is found out that the structure of the solid solution α-MnH 0.073 belongs to the same spatial group I-43m as the structure of α-Mn [ru
Wen, Cuilian; Wei, Ying; Tang, Dian; Sa, Baisheng; Zhang, Teng; Chen, Changxin
2017-07-07
The tolerance of the electrode against the CO species absorbed upon the surface presents the biggest dilemma of the alcohol fuel cells. Here we report for the first time that the inclusion of (Zr, Ce)O 2 solid solution as the supporting material can significantly improve the anti-CO-poisoning as well as the activity of Pd/C catalyst for ethylene glycol electro-oxidation in KOH medium. In particular, the physical origin of the improved electrocatalytic properties has been unraveled by first principle calculations. The 3D stereoscopic Pd cluster on the surface of (Zr, Ce)O 2 solid solution leads to weaker Pd-C bonding and smaller CO desorption driving force. These results support that the Pd/ZrO 2 -CeO 2 /C composite catalyst could be used as a promising effective candidate for direct alcohol fuel cells application.
Thermoelectric properties of Bi2Te3 base solid solutions in the Bi2Te3-InS system
International Nuclear Information System (INIS)
Safarov, M.G.; Rustamov, P.G.; Alidzhanov, M.A.
1979-01-01
The rich Bi 2 Te 3 part ot the Bi 2 Te 3 -InS constitutional diagram has been studied with a view to produce new Bi 2 Te 3 -based solid solutions and to establish the maximum solubility of InS in Bi 2 Te 3 . The methods of differential-thermal, X-ray phase and microstructural analysis have been used. The alloys microhardness, density and thermal electric properties have been measured. A large region of Bi 2 Te 3 -based restricted solid solutions has been detected; it reaches 14.0 mol.% InS at room temperature. Studied have been the thermoelectromotive forces, electric and thermal conductivity of the alloys, containing up to 5 mol.% InS in the 300-700 K temperature range
Czech Academy of Sciences Publication Activity Database
Niederhafner, Petr; Gut, Vladimír; Ježek, Jan; Buděšínský, Miloš; Kašička, Václav; Wünsch, Erich; Hlaváček, Jan
2010-01-01
Roč. 39, č. 3 (2010), s. 641-650 ISSN 0939-4451 R&D Projects: GA ČR GA203/03/1362; GA ČR GA203/07/1517 Institutional research plan: CEZ:AV0Z40550506 Keywords : hinge region * immunoglobulin * prion protein * solution synthesis * solid phase synthesis Subject RIV: CC - Organic Chemistry Impact factor: 4.106, year: 2010
Luminescence of Ce3+ ions in Y3Al5O12 - Y3Ga5O12 solid solution
International Nuclear Information System (INIS)
Zorenko, Yu.V.; Nazar, I.V.; Limarenko, L.N.; Pashkovskij, M.V.
1996-01-01
Regularities of changes in spectral and energetic characteristics of the Ce 3+ ions radiation in the Y 3 Al 5-x Ga x O 12 solid solutions, related to change in the matrix crystal field force and dissipation of the luminescence excitation energy because of transfers between the valency zone ceiling and the Ce 3+ excited ion basis state are obtained. 9 refs., 3 figs., 1 tab
Structural and magnetic properties of UCo1/3T2/3Al solid solutions (T = Ru, Pt, Rh)
International Nuclear Information System (INIS)
Andreev, A. V.; Bordallo, H. N.; Chang, S.; Nakotte, H.; Schultz, A. J.; Sechovsky, V.; Torikachvili, M. S.
1999-01-01
We report on neutron diffraction studies of UCo 1/3 T 2/3 Al (T = Ru, Pt, Rh). All three solid solutions form in the hexagonal ZrNiAl structure. The Ru-containing compound is found to be chemically ordered, while the Pt-containing compound is nearly disordered and the Rh-containing compound is purely disordered. All three compounds exhibit long-range magnetic order with rather small U moments
(_{1}_{-}_{x}Pu_{x})Sb solid solutions. 1. Magnetic configurations
DEFF Research Database (Denmark)
Normile, P.S.; Stirling, W.G.; Mannix, D.
2002-01-01
Neutron and resonant x-ray magnetic scattering studies have been performed on single crystals of three compositions, x=0.25, 0.50, and 0.75 of the (U1-xPux)Sb solid solution. Neutron diffraction has established the ordering wave vector (k=1 for x=0.25 and 0.50, as in x=0, USb, and k=0.25 for x=0....
Observing bose condensations of cooper pairs in semiconductor solid solutions (Pb1-xSnx)1-zInzTe
International Nuclear Information System (INIS)
Nemov, S.A.; Seregin, P.L.; Volkov, V.P.; Seregin, N.P.; Shamshur, D.V.
2004-01-01
It has been established using the emission Moessbauer spectroscopy method on the isotope 73 As( 73 Ge) that superconducting transition in the solid solutions (Pb 1-x Sn x ) 1-z In z Te (temperature of phase transition ∼ 4 K) leads to the change of the electron density in the metal sites, while in the anion sites no change in the electronic density has been observed [ru
Pseudo-solid-solution CuCo2O4/C nanofibers as excellent anodes for lithium ion batteries
International Nuclear Information System (INIS)
Zhang, Hang; Tang, Zhiyong; Zhang, Kang; Wang, Lei; Shi, Huimin; Zhang, Guanhua; Duan, Huigao
2017-01-01
Ternary transition metal oxides have received intense research interest as electrode materials for lithium ion batteries, due to their high specific capacity originating from the synergic effects of multiple metal active sites. Reducing the size of metal oxides nanoparticles and dispersing these nanoparticles in carbon matrix are considering effective strategies to improve the electrochemical performance of transition metal oxides. Ternary CuCo 2 O 4 nanoclusters ultra-uniformly dispersed in carbon nanofiber matrix forming a pseudo-solid-solution structure are successfully synthesized by a facile electrospinning method followed by an appropriate annealing process. As the anodic electrode for lithium ion batteries, the pseudo-solid-solution CuCo 2 O 4 /C electrode exhibits a high reversible specific capacity, improved rate capacity and excellent cycling stability. A discharge capacity of 865 mAh g −1 is obtained at the current density of 200 mA g −1 after 400 cycles. Surprisingly, the electrode still retains about 610 mAh g −1 after 800 cycles even at the current density of 600 mA g −1 . The superior lithium storage performance of the pseudo-solid-solution CuCo 2 O 4 /C composites is mainly attributed to the unique amorphous structure. The ultrafine CuCo 2 O 4 nanoclusters uniformly dispersed in carbon matrix can buffer the volume change and improve the conductivity of the metal oxide based electrode, guaranteeing the structure stability and fast electron transfer.
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.
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
Solid solutions of platinum(II) and palladium(II) oxalato-complex salt as precursors of nanoalloys
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.
Nonlinear Dispersive Elastic Waves in Solids: Exact, Approximate, and Numerical Solutions
Khajehtourian, Romik
Wave motion lies at the heart of many disciplines in the physical sciences and engineering. For example, problems and applications involving light, sound, heat, or fluid flow are all likely to involve wave dynamics at some level. A particular class of problems is concerned with the propagation of elastic waves in a solid medium, such as a fiber-reinforced composite material responding to vibratory excitations, or soil and rock admitting seismic waves moments after the onset of an earthquake, or phonon transport in a semiconducting crystal like silicon. Regardless of the type of wave, the dispersion relation provides a fundamental characterization of the elastodynamic properties of the medium. The first part of the dissertation examines the propagation of a large-amplitude elastic wave in a one-dimensional homogeneous medium with a focus on the effects of inherent nonlinearities on the dispersion relation. Considering a thin rod, where the thickness is small compared to the wavelength, an exact, closed-form formulation is presented for the treatment of two types of nonlinearity in the strain-displacement gradient relation: Green-Lagrange and Hencky. The derived relation is then verified by direct time-domain simulations, examining both instantaneous dispersion (by direct observation) and short-term, pre-breaking dispersion (by Fourier transformation). A high-order perturbation analysis is also conducted yielding an explicit analytical space-time solution, which is shown to be spectrally accurate. The results establish a perfect match between theory and simulation and reveal that regardless of the strength of the nonlinearity, the dispersion relation fully embodies all information pertaining to the nonlinear harmonic generation mechanism that unfolds as an arbitrary-profiled wave evolves in the medium. In the second part of the dissertation, the analysis is extended to a continuous periodic thin rod exhibiting multiple phases or embedded local resonators. The
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
International Nuclear Information System (INIS)
Thien, Bruno M.J.; Kulik, Dmitrii A.; Curti, Enzo
2014-01-01
Highlights: • There are several models able to describe trace element partitioning in growing minerals. • To describe complex systems, those models must be embedded in a geochemical code. • We merged two models into a unified one suitable for implementation in a geochemical code. • This unified model was tested against coprecipitation experimental data. • We explored how our model reacts to solution depletion effects. - Abstract: Thermodynamics alone is usually not sufficient to predict growth-rate dependencies of trace element partitioning into host mineral solid solutions. In this contribution, two uptake kinetic models were analyzed that are promising in terms of mechanistic understanding and potential for implementation in geochemical modelling codes. The growth Surface Entrapment Model (Watson, 2004) and the Surface Reaction Kinetic Model (DePaolo, 2011) were shown to be complementary, and under certain assumptions merged into a single analytical expression. This Unified Uptake Kinetics Model was implemented in GEMS3K and GEM-Selektor codes ( (http://gems.web.psi.ch)), a Gibbs energy minimization package for geochemical modelling. This implementation extends the applicability of the unified uptake kinetics model to accounting for non-trivial factors influencing the trace element partitioning into solid solutions, such as the changes in aqueous solution composition and speciation, or the depletion effects in closed geochemical systems
Crystal structure and magnetic properties of the solid-solution phase Ca3Co2-v Sc v O6
International Nuclear Information System (INIS)
Hervoches, Charles H.; Fredenborg, Vivian Miksch; Kjekshus, Arne; Fjellvag, Helmer; Hauback, Bjorn C.
2007-01-01
The two crystallographically non-equivalent Co atoms of the quasi-one-dimensional crystal structure of Ca 3 Co 2 O 6 form chains with alternating, face-sharing polyhedra of Co2O 6 trigonal prisms and Co1O 6 octahedra. This compound forms a substitutional solid-solution phase with Sc, in which the Sc atoms enter the Co2 sublattice exclusively. The homogeneity range of Ca 3 Co 2- v Sc v O 6 (more specifically Ca 3 Co1Co2 1- v Sc v O 6 ) extends up to v∼0.55. The crystal structure belongs to space group R3-barc with lattice parameters (in hexagonal setting): 9.0846(3)≤a≤9.1300(2) A and 10.3885(4)≤c≤10.4677(4) A. The magnetic moment decreases rapidly with increasing amount of the non-magnetic Sc solute in the lattice. - Graphical abstract: The quasi-one-dimensional Ca 3 Co 2 O 6 phase forms a substitutional solid-solution system with Sc, in which the Sc atoms enter the Co2 sublattice exclusively. The homogeneity range of Ca 3 Co 2- v Sc v O 6 extends up to v∼0.55. The magnetic moment decreases rapidly with increasing amount of the non-magnetic Sc solute in the lattice
Zheng, Haipeng; Fei, Pengfei; Wu, Ruizhi; Hou, Legan; Zhang, Milin
2018-03-01
The microstructure and the hardness of cast magnesium alloy Mg - 9% Li - 6% Al are studied after a treatment for solid solution at 300, 350, and 450°C for 0.5 - 5 h. The phase composition of the alloy is represented by α-Mg, β-Li, thin-plate and faceted particles of an AlLi phase, and particles of a MgLi2Al θ-phase. The θ-phase dissolves in the matrix in the initial stage of the solution treatment, which causes growth in the hardness of the alloy. At a temperature above 350°C the AlLi phase dissolves giving way to short rod-like precipitates of a θ-phase, which remain steady in the process of solution treatment. The hardness of the alloy deceases in this stage for this reason.
International Nuclear Information System (INIS)
Coulier, Yohann; Tremaine, Peter R.
2014-01-01
Highlights: • Heats of solution of NaAlO 2 (s) were measured at five temperatures up to 250 °C. • Standard molar enthalpies of solution were determined from the measured heats of solution. • Standard molar enthalpies of solution were correlated with the density model. • The density model allows us to determine the standard molar heat capacities of reaction. - Abstract: Heats of solution of sodium aluminum oxide, NaAlO 2 (s), were measured in aqueous sodium hydroxide solutions using a Tian–Calvet heat-flow calorimeter (Setaram, Model C80) with high pressure “batch cells” made of hastelloy C-276, at five temperatures from (373.15 to 523.15) K, steam saturation pressure, and concentrations from (0.02 to 0.09) mol · kg −1 . Standard molar enthalpies of solution, Δ soln H ∘ , and relative standard molar enthalpies, [H ∘ (T) − H ∘ (298.15 K)], of NaAl(OH) 4 (aq) were determined from the measured heats of solution. The results were fitted with the “density” model. The temperature dependence of Δ soln H ∘ from the model yielded the standard molar heat capacities of reaction, Δ soln C p ∘ , from which standard partial molar heat capacities for aqueous aluminate, C p ∘ [A1(OH) 4 − ,aq], were calculated. Standard partial molar enthalpies of formation, Δ f H ∘ , and entropies, S ∘ , of A1(OH) 4 − (aq) were also determined. The values for C p ∘ [A1(OH) 4 − ,aq] agree with literature data determined up to T = 413 K from enthalpy of solution and heat capacity measurements to within the combined experimental uncertainties. They are consistent with differential heat capacity measurements up to T = 573 K from Schrödle et al. (2010) [29] using the same calorimeter, but this method has the advantage that measurements could be made at much lower concentrations in the presence of an excess concentration of ligand. To our knowledge, these are the first standard partial molar heat capacities measured under hydrothermal conditions by the
International Nuclear Information System (INIS)
Yi, Peng; Cammarata, Robert C.; Falk, Michael L.
2016-01-01
Dislocation mobility in a solid solution was studied using atomistic simulations of an Mg/Al system. The critical resolved shear stress (CRSS) for the dislocations on the basal plane was calculated at temperatures from 0 K to 500 K with solute concentrations from 0 to 7 at%, and with four different strain rates. Solute hardening of the CRSS is decomposed into two contributions: one scales with c 2/3 , where c is the solute concentration, and the other scales with c 1 . The former was consistent with the Labusch model for local solute obstacles, and the latter was related to the athermal plateau stress due to the long range solute effect. A thermo-mechanical model was then used to analyze the temperature and strain rate dependences of the CRSS, and it yielded self-consistent and realistic results. The scaling laws were confirmed and the thermo-mechanical model was successfully parameterized using experimental measurements of the CRSS for Mg/Al alloys under quasi-static conditions. The predicted strain rate sensitivity from the experimental measurements of the CRSS is in reasonable agreement with separate mechanical tests. The concentration scaling and the thermo-mechanical relationships provide a potential tool to analytically relate the structural and thermodynamic parameters on the microscopic level with the macroscopic mechanical properties arising from dislocation mediated deformation.
Tetraphenylimidodiphosphinate as solid phase extractant for preconcentrative separation of thorium from aqueous solution
International Nuclear Information System (INIS)
Na Liu; Yanfei Wang; Chuhua He
2016-01-01
A simple and reliable method for solid phase extraction of thorium using tetraphenylimidodiphosphinate is presented. The solid phase extraction process was optimized at equilibrium time 3 h, pH = 4.5, initial concentration 30 mg L -1 and extractant dosage 0.01 g with 98.95 % of removal efficiency and 29.68 mg g -1 of adsorption capacity. The interfering ions experiments indicated that it had almost no effect on thorium adsorption. Kinetics data follow the pseudo-first-order model and equilibrium data agreed with the Langmuir isotherm model very well. FT-IR analysis indicated that imino group and phosphoryl acted as the significant roles in the solid phase extraction process. (author)
Steam jet mill-a prospective solution to industrial exhaust steam and solid waste.
Zhang, Mingxing; Chen, Haiyan
2018-04-20
Bulk industrial solid wastes occupy a lot of our resources and release large amounts of toxic and hazardous substances to the surrounding environment, demanding innovative strategies for grinding, classification, collection, and recycling for economically ultrafine powder. A new technology for grinding, classification, collection, and recycling solid waste is proposed, using the superheated steam produced from the industrial exhaust steam to disperse, grind, classify, and collect the industrial solid waste. A large-scale steam jet mill was designed to operate at an inlet steam temperature 230-300 °C and an inlet pressure of 0.2-0.6 MPa. A kind of industrial solid waste fluidized-bed combustion ashes was used to grinding tests at different steam temperatures and inlet pressures. The total process for grinding, classification, and collection is drying. Two kinds of particle sizes are obtained. One particle size is d 50 = 4.785 μm, and another particle size is d 50 = 8.999 μm. For particle size d 50 = 8.999 μm, the inlet temperature is 296 °C and an inlet pressure is 0.54 MPa for the grinding chamber. The steam flow is 21.7 t/h. The yield of superfine powder is 73 t/h. The power consumption is 3.76 kW h/t. The obtained superfine powder meets the national standard S95 slag. On the basis of these results, a reproducible and sustainable industrial ecological protocol using steam produced by industrial exhaust heat coupled to solid waste recycling is proposed, providing an efficient, large-scale, low-cost, promising, and green method for both solid waste recovery and industrial exhaust heat reutilization.
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.
International Nuclear Information System (INIS)
Hoda, Numan; Budama, Leyla; Çakır, Burçin Acar; Topel, Önder; Ozisik, Rahmi
2013-01-01
Graphical abstract: TEM image of Pt nanoparticles produced by reducing by NaBH 4 within PB-b-PEO micelles in aqueous media (scale bar 1 nm). - Highlights: • Pt nanoparticles were synthesized within amphiphilic diblock copolymer micelles. • The effects of reducing agents and precursor dose on Pt np size were investigated. • The effect on fabrication of Pt np by reducing in aqueous and solid phases was compared. • The size of nanoparticles was about 1.4 nm for all doses and reducing agents types. - Abstract: Fabrication of Pt nanoparticles using an amphiphilic copolymer template in aqueous solution was achieved via polybutadiene-block-polyethyleneoxide copolymer micelles, which acted as nanoreactors. In addition, Pt nanoparticles were synthesized using hydrogen gas as the reducing agent in solid state for the first time to compare against solution synthesis. The influences of loaded precursor salt amount to micelles and the type of reducing agent on the size of nanoparticles were investigated through transmission electron microscopy. It was found that increasing the ratio of precursor salt to copolymer and using different type of reducing agent, even in solid phase reduction, did not affect the nanoparticle size. The average size of Pt nanoparticles was estimated to be 1.4 ± 0.1 nm. The reason for getting same sized nanoparticles was discussed in the light of nucleation, growth process, stabilization and diffusion of nanoparticles within micelles