Solution combustion derived nanocrystalline macroporous wollastonite ceramics
Energy Technology Data Exchange (ETDEWEB)
Sreekanth Chakradhar, R.P. [Department of Physics, Indian Institute of Science, Bangalore 560012 (India)]. E-mail: chakra72@physics.iisc.ernet.in; Nagabhushana, B.M. [Department of Chemistry, Bangalore University, Bangalore 560001 (India); Chandrappa, G.T. [Department of Chemistry, Bangalore University, Bangalore 560001 (India)]. E-mail: gtchandrappa@yahoo.co.in; Ramesh, K.P. [Department of Physics, Indian Institute of Science, Bangalore 560012 (India); Rao, J.L. [Department of Physics, S.V. University, Tirupati 517502 (India)
2006-01-10
Macroporous nanocrystalline wollastonite (CaSiO{sub 3}) ceramic powders have been prepared by a simple, low-temperature initiated, self-propagating and gas producing solution combustion process. The effects of temperature on crystalline phase formation, amount of porogens and particle size of porous CaSiO{sub 3} and its structure have been investigated. It is observed that heat-treated wollastonite at 950 and 1200 deg. C shows single phase of {beta}-CaSiO{sub 3} and {alpha}-CaSiO{sub 3}, respectively. The results show that the phase transformation temperatures of the solution combustion derived wollastonite powder were found to be lower compare to the powders obtained via solid-state reaction method. It was observed that the average particle size of the annealed CaSiO{sub 3} samples is in the range 29-50 nm. The density of the as formed powder is 1.73 g cm{sup -3} where as the bulk density is 2.321 g cm{sup -3}, which corresponds nearly to 80% of the theoretical density (2.91 g cm{sup -3}). The samples calcined for 3 h at 950 deg. C have 51.1% of theoretical density with a porosity of 17.5%, however, the porosity increases with calcination and at 1200 deg. C has a large porosity of 31.6%. The microstructure and morphology were studied by scanning electron microscope (SEM) and it is interesting to note that with increase in calcination temperature, the samples become more porous and the pore diameter increases from 0.25 to 8 {mu}m. The surface area of the as formed, 950 and 1200 deg. C calcined samples were 31.93, 0.585 and 3.48 m{sup 2} g{sup -1}, respectively. The structure of CaSiO{sub 3} has been investigated by {sup 29}Si MAS NMR. The shape of the Q{sub n} distribution has been examined for the as formed CaSiO{sub 3} as well as calcined (950 deg. C) sample.
Solution combustion derived nanocrystalline macroporous wollastonite ceramics
International Nuclear Information System (INIS)
Macroporous nanocrystalline wollastonite (CaSiO3) ceramic powders have been prepared by a simple, low-temperature initiated, self-propagating and gas producing solution combustion process. The effects of temperature on crystalline phase formation, amount of porogens and particle size of porous CaSiO3 and its structure have been investigated. It is observed that heat-treated wollastonite at 950 and 1200 deg. C shows single phase of β-CaSiO3 and α-CaSiO3, respectively. The results show that the phase transformation temperatures of the solution combustion derived wollastonite powder were found to be lower compare to the powders obtained via solid-state reaction method. It was observed that the average particle size of the annealed CaSiO3 samples is in the range 29-50 nm. The density of the as formed powder is 1.73 g cm-3 where as the bulk density is 2.321 g cm-3, which corresponds nearly to 80% of the theoretical density (2.91 g cm-3). The samples calcined for 3 h at 950 deg. C have 51.1% of theoretical density with a porosity of 17.5%, however, the porosity increases with calcination and at 1200 deg. C has a large porosity of 31.6%. The microstructure and morphology were studied by scanning electron microscope (SEM) and it is interesting to note that with increase in calcination temperature, the samples become more porous and the pore diameter increases from 0.25 to 8 μm. The surface area of the as formed, 950 and 1200 deg. C calcined samples were 31.93, 0.585 and 3.48 m2 g-1, respectively. The structure of CaSiO3 has been investigated by 29Si MAS NMR. The shape of the Qn distribution has been examined for the as formed CaSiO3 as well as calcined (950 deg. C) sample
Asymptotic solutions of magnetohydrodynamics equations near the derivatives discontinuity lines
International Nuclear Information System (INIS)
Asymptotic solutions of one-dimensional and scalar magnetohydrodynamics equations near the derivatives discontinuity lines have been discussed. The equations of magnetohydrodynamics for the cases of finite and infinite conductivities are formulated and the problem of eigenvalues and eigenvectors is solved. The so called transport equations which describe the behaviour of derivatives in solutions of the quasilinear equations have been used to find the asymptotic solutions of the magnetohydrodynamics equations. (S.B.)
Deriving N-soliton solutions via constrained flows
Zeng, Yunbo
2000-01-01
The soliton equations can be factorized by two commuting x- and t-constrained flows. We propose a method to derive N-soliton solutions of soliton equations directly from the x- and t-constrained flows.
Mika Tanda
2015-01-01
We compute alien derivatives of the WKB solutions of the Gauss hypergeometric differential equation with a large parameter and discuss the singularity structures of the Borel transforms of the WKB solution expressed in terms of its alien derivatives.
Institute of Scientific and Technical Information of China (English)
DONG BoQing; JIANG Wei
2008-01-01
This article concerns large time behavior of Ladyzhenskaya model for incompressible viscous flows in R3. Based on linear Lp-Lq estimates, the auxiliary decay properties of the solutions and generalized Gronwall type arguments, some optimal upper and lower bounds for the decay of higher order derivatives of solutions are derived without assuming any decay properties of solutions and using Fourier splitting technology.
Spectral characteristics of light generation in solutions of phthalimide derivatives
Energy Technology Data Exchange (ETDEWEB)
Gladchenko, L.F.; Das' ko, A.D.; Pikulik, L.G.
1975-01-01
A presentation is given of the results of investigating frequency tuning of laser light generated in solutions of phthalimides. It is shown that by varying the organic solute, by using binary mixtures of organic solutes and by changing the solution temperature it is possible to control the overall wide band of light generation over wide limits (up to 4000 cm/sup -1/). By using selective elements in the resonator it is possible to obtain tuning to 3000 cm/sup -1/ without varying the working solution. (SJR)
Directory of Open Access Journals (Sweden)
Ram K. Saxena
2015-04-01
Full Text Available This article is in continuation of the authors research attempts to derive computational solutions of an unified reaction-diffusion equation of distributed order associated with Caputo derivatives as the time-derivative and Riesz-Feller derivative as space derivative. This article presents computational solutions of distributed order fractional reaction-diffusion equations associated with Riemann-Liouville derivatives of fractional orders as the time-derivatives and Riesz-Feller fractional derivatives as the space derivatives. The method followed in deriving the solution is that of joint Laplace and Fourier transforms. The solution is derived in a closed and computational form in terms of the familiar Mittag-Leffler function. It provides an elegant extension of results available in the literature. The results obtained are presented in the form of two theorems. Some results associated specifically with fractional Riesz derivatives are also derived as special cases of the most general result. It will be seen that in case of distributed order fractional reaction-diffusion, the solution comes in a compact and closed form in terms of a generalization of the Kampé de Fériet hypergeometric series in two variables. The convergence of the double series occurring in the solution is also given.
Spherically Symmetric Solutions in Higher-Derivative Gravity
Lü, H; Pope, C N; Stelle, K S
2015-01-01
Extensions of Einstein gravity with quadratic curvature terms in the action arise in most effective theories of quantised gravity, including string theory. This article explores the set of static, spherically symmetric and asymptotically flat solutions of this class of theories. An important element in the analysis is the careful treatment of a Lichnerowicz-type `no-hair' theorem. From a Frobenius analysis of the asymptotic small-radius behaviour, the solution space is found to split into three asymptotic families, one of which contains the classic Schwarzschild solution. These three families are carefully analysed to determine the corresponding numbers of free parameters in each. One solution family is capable of arising from coupling to a distributional shell of matter near the origin; this family can then match on to an asymptotically flat solution at spatial infinity without encountering a horizon. Another family, with horizons, contains the Schwarzschild solution but includes also non-Schwarzschild black...
Spherically symmetric solutions in higher-derivative gravity
Lü, H.; Perkins, A.; Pope, C. N.; Stelle, K. S.
2015-12-01
Extensions of Einstein gravity with quadratic curvature terms in the action arise in most effective theories of quantized gravity, including string theory. This article explores the set of static, spherically symmetric and asymptotically flat solutions of this class of theories. An important element in the analysis is the careful treatment of a Lichnerowicz-type "no-hair" theorem. From a Frobenius analysis of the asymptotic small-radius behavior, the solution space is found to split into three asymptotic families, one of which contains the classic Schwarzschild solution. These three families are carefully analyzed to determine the corresponding numbers of free parameters in each. One solution family is capable of arising from coupling to a distributional shell of matter near the origin; this family can then match onto an asymptotically flat solution at spatial infinity without encountering a horizon. Another family, with horizons, contains the Schwarzschild solution but includes also non-Schwarzschild black holes. The third family of solutions obtained from the Frobenius analysis is nonsingular and corresponds to "vacuum" solutions. In addition to the three families identified from near-origin behavior, there are solutions that may be identified as "wormholes," which can match symmetrically onto another sheet of spacetime at finite radius.
Solution derived ZnO:Al films with low resistivity
SCHELLENS, Kevin; Capon, B.; De Dobbelaere, Christopher; Detavernier, C.; Hardy, An; VAN BAEL, Marlies
2012-01-01
ZnO:Al thin films were prepared via chemical solution deposition, using 2-butoxyethanol as an alternative for 2-methoxyethanol, which is more commonly used, but acutely toxic. The precursor solutions can be readily spin coated. The phase, morphology, electrical and optical properties of the deposited films are investigated, by XRD (X-ray diffraction), scanning electron microscopy, a two-point contact measurement and UV-vis spectrophotometry respectively. This way, the effect of this solvent i...
Black hole solutions coupled to Born-Infeld electrodynamics with derivative corrections
Tamaki, Takashi
2003-01-01
We investigate black hole solutions in the Einstein-Born-Infeld system. We clarify the role played by derivative corrections to the Born-Infeld (BI) action. The qulitative differences from the case without derivative corrections are: (i) there is no particlelike solution. (ii) the existence of the inner horizon is restricted to the near extreme solutions. (iii) contribution of the BI parameter $b$ to the gravitational mass and the Hawking temperature works in the opposite direction.
On the derivation and solution of the black-scholes option pricing model
David CHAPPELL
1992-01-01
The derivation and solution of the celebrated Black-Scholes Option Pricing Formula is set out in rather more detail than has appeared in the literature so far. One problem with the Black-Scholes analysis is that the mathematical skills required in the derivation and particularly in the solution of the model are fairly advanced and probably unfamiliar to most economists. This paper derives the partial differential equation for the call option price and gives full details of its sol...
Solution Processable Symmetric 4-Alkylethynylbenzene End-Capped Anthracene Derivatives
International Nuclear Information System (INIS)
New candidates composed of anthracene and 4-alkylethynylbenzene end-capped oligomers for OTFTs were synthesized under Sonogashira coupling reaction conditions. All oligomers were characterized by FT-IR, mass, UV-visible, and PL emission spectrum analyses, cyclic voltammetry (CV), differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), 1H-NMR, and 13C-NMR. Investigation of their physical properties showed that the oligomers had high oxidation potential and thermal stability. Thin films of DHPEAnt and DDPEAnt were characterized by spin coating them onto Si/SiO2 to fabricate top-contact OTFTs. The devices prepared using DHPEAnt and DDPEAnt showed hole field-effect mobilities of 4.0 x 10-3 cm2/Vs and 2.0 x 10-3 cm2/Vs, respectively, for solution-processed OTFTs
Analytically-derived sensitivities in one-dimensional models of solute transport in porous media
Knopman, D.S.
1987-01-01
Analytically-derived sensitivities are presented for parameters in one-dimensional models of solute transport in porous media. Sensitivities were derived by direct differentiation of closed form solutions for each of the odel, and by a time integral method for two of the models. Models are based on the advection-dispersion equation and include adsorption and first-order chemical decay. Boundary conditions considered are: a constant step input of solute, constant flux input of solute, and exponentially decaying input of solute at the upstream boundary. A zero flux is assumed at the downstream boundary. Initial conditions include a constant and spatially varying distribution of solute. One model simulates the mixing of solute in an observation well from individual layers in a multilayer aquifer system. Computer programs produce output files compatible with graphics software in which sensitivities are plotted as a function of either time or space. (USGS)
Exact solutions of a class of fractional Hamiltonian equations involving Caputo derivatives
Energy Technology Data Exchange (ETDEWEB)
Baleanu, Dumitru [Department of Mathematics and Computer Sciences, Faculty of Arts and Sciences, Cankaya University, Ankara 06530 (Turkey); Trujillo, Juan J [Departamento de Analisis Matematico, University of La Laguna, 38271 La Laguna, Tenerife (Spain)], E-mail: dumitru@cankaya.edu.tr, E-mail: JTrujill@ullmat.es, E-mail: baleanu@venus.nipne.ro
2009-11-15
The fractional Hamiltonian equations corresponding to the Lagrangians of constrained systems within Caputo derivatives are investigated. The fractional phase space is obtained and the exact solutions of some constrained systems are obtained.
Derivative Estimates for the Solution of Hyp erb olic Aﬃne Sphere Equation
Institute of Scientific and Technical Information of China (English)
Wu Ya-dong; Rong Xiao-chun
2015-01-01
Considering the hyperbolic affine sphere equation in a smooth strictly convex bounded domain with zero boundary values, the sharp derivative estimates of any order for its convex solution are obtained.
Non-traditional solutions of cellulose and it's derivatives and their processing products
Grinshpan, D. D.; Savitskaya, T. A.; Tsygankova, N. G.
2003-01-01
The main achievements of the Laboratory of cellulose solutions and their processing products in the field of the elaboration of new cellulose dissolving processes, the homogeneous synthesis of cellulose derivatives, the elaboration of the incompatible polymer solutions stabilization, the creation of new film - fabric materials and filtering equipments on their base, the preparation of hard quickly disintegrated drug forms (tablets, granules) using new water soluble cellulose derivative have b...
Indian Academy of Sciences (India)
H Mohan; A Adhikary; V Jain; J P Mittal
2000-08-01
The pulse radiolysis technique has been employed to investigate the reaction of DNA-minor-groove ligand bisbenzimidazole Hoechst 33258 with pyrimidine and purine nucleotide-derived radicals. Formation of an N-centred Hoechst-33258 radical is observed. Bimolecular rate constants and the yields of Hoechst-33258 radical have been evaluated. While the rate constant for the reaction of pyrimidine-derived radicals with Hoechst-33258 remained the same (1-2) × 109 dm3 mol-1s-1, the yields of the Hoechst-33258 radical varied from 25% (5 -cytidine monophosphate) to 75% (5 -guanosine monophosphate) under anoxic conditions. The rate constant values for the reaction of purine-derived radicals with Hoechst-33258, under oxic and anoxic conditions, remained the same whereas with pyrimidine-derived radicals, the rate constant value under oxic conditions was about two orders of magnitude lower than under anoxic conditions. The difference in the yields of Hoechst-33258 radical with various nucleotide-derived radicals suggest the formation of different types of radicals and that the reaction mainly occurs by electron transfer from Hoechst-33258 to the nucleotide radicals.
Interaction of derived polymers from pyrrole with biocompatible solutions
International Nuclear Information System (INIS)
This work presents a study about the synthesis by plasma, the electric properties and superficial interaction of polymers derived from pyrrole doped with Iodine with potential use as bio material. Poly-pyrrole is a semiconductor and biocompatible polymer with potential application in the development of artificial muscles and implants where the electric interaction between cells and material is an important variable. The syntheses were made at 13.5 MHz in a glass tubular reactor of 1500 cm3 with electrodes of 6.5 cm diameter and stainless steel flanges. An electrode was connected to the RF terminal of the power supply that is combined with a matching coupling resistance. The monomer and dopant used in this work were pyrrole and Iodine respectively, in closed containers. They were vaporized and injected separately into the reactor at room temperature and 0.1 mbar. The vapors of the reagents mixed freely in the reactor. The synthesis time was 240 min at 40, 60, 80 and 100 W. The polymers were obtained as thin films adhered to the reactor walls. The films were washed and swollen with distilled water and removed from the reactor walls with a small spatula. The polymers were irradiated with gamma rays at 18 and 22 KGy. Due to the fact that the doses are cumulative, the final dose applied was 40 KGy. The polymers characterization was carried out by Fourier Transform Infrared Spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy, contact angle, electrical conductivity and X-ray diffraction. The analyses indicates that the polymers have very similar structure in almost the entire power range, showing C-O, C=C, C-H, O-H, N-H bonds with a predominantly amorphous structure. The TGA analyses showed that the material has 4 or 5 loses of material. The first one starts after that 115 C except for the material irradiated at 40 KGy, this one begins in 87 C, the second one is in the interval of 196 and 295 C, the third one between 311 and 500 C, and the last
Positive Solution of a Nonlinear Fractional Differential Equation Involving Caputo Derivative
Directory of Open Access Journals (Sweden)
Changyou Wang
2012-01-01
Full Text Available This paper is concerned with a nonlinear fractional differential equation involving Caputo derivative. By constructing the upper and lower control functions of the nonlinear term without any monotone requirement and applying the method of upper and lower solutions and the Schauder fixed point theorem, the existence and uniqueness of positive solution for the initial value problem are investigated. Moreover, the existence of maximal and minimal solutions is also obtained.
Lead and copper removal from aqueous solutions by porous glass derived calcium hydroxyapatite
International Nuclear Information System (INIS)
Graphical abstract: . Adsorption of Pb2+ increases with the increase in NaCl volume percentage (1:0%, 2:30%, 3:40%, 4:40%) of the Glass Derived Hydroxyapatite and reaches equilibrium after 24 h. Highlights: → Novel porous glass derived hydroxyapatite matrix is prepared. → Glass derived hydroxyapatite matrix adsorbs lead and copper ions in solutions effectively. → Two adsorption mechanisms including ion exchange theory and the dissolution and precipitation theory are involved in removal of the heavy metal ions from the solutions. - Abstract: A porous glass was prepared by sintering Na2O-CaO-B2O3 glass powder with powdered sodium chloride. Subsequently, the sodium chloride was dissolved in water resulting in a highly porous material. A sample was prepared consisting of 60 vol% glass and 40 vol% salt which both had particle sizes 2HPO4 solutions at room temperature for 1 day. The porous glass derived hydroxyapatite matrix was then processed for removing lead and copper ions from aqueous solutions. The results showed that the glass derived calcium hydroxyapatite matrix effectively immobilizes lead and copper ions in solution. The adsorption mechanism was investigated by the X-ray Diffraction (XRD) and Scanning Electron Microscopy including Energy Dispersive X-Ray Spectrometry (SEM-EDX).
Thermodynamic properties of ethanol solution of chiral camphors and its derivatives
Energy Technology Data Exchange (ETDEWEB)
Kimura, Takayoshi [Department of Chemistry, Kinki University, Kowakae, Higashi-Osaka 577-8502 (Japan)], E-mail: kimura@chem.kindai.ac.jp; Iwama, Sekai; Kido, Satoko; Khan, Mohammad Abdullah [Department of Chemistry, Kinki University, Kowakae, Higashi-Osaka 577-8502 (Japan)
2009-10-15
Enthalpies of mixing and the densities of ethanol solution of R- and S-enantiomers of camphor, 10-camphorsulfonamide, 10-camphorsulfonic acid, camphorquinone, and 10-camphorsulfonyl chloride have been measured for a wide range of mole fractions of heterochiral components at 298.15 K. Enthalpies of mixing were exothermic for all concentrations and heterochiral solutions were more stable than each of the homochiral solutions. Enthalpic stabilization of mixing of heterochiral solutions was increased with a decreasing concentration of all the camphor derivatives measured. The sequence of enthalpic stabilization on mixing was 10-camphorsulfonyl chloride, 10-camphorsulfonic acid, 10-camphorsulfonamide, camphor, and camphorquinone. Apparent molar volumes were determined and excess volumes of mixing of heterochiral solutions were small and negative. Enthalpic stabilizations were found to be dependent on dipole-dipole interaction between solutes and solvents.
Classification of kink type solutions to the extended derivative nonlinear Schrödinger equation
DEFF Research Database (Denmark)
Wyller, J.; Fla, T.; Juul Rasmussen, J.
1998-01-01
The Raman Extended Derivative Non Linear Schrodinger (R-EDNLS) equation which models single mode propagation in optical fibers, is shown to possess travelling and stationary kink envelope solutions of monotonic and oscillatory type. These structures have been called optical shocks in analogy with...... hydrodynamical shocks or optical double layers in analogy with electrostatic double layers in plasma physics. Hydrodynamical equations for the action density and local wave number are derived and shock wave solutions of the Rankine-Hugionot type are constructed. They are consistent with the kink structures when...
S-asymptotically -periodic Solutions of R-L Fractional Derivative-Integral Equation
Institute of Scientific and Technical Information of China (English)
WANG Bing
2015-01-01
The aim of this paper is to study the S-asymptotically ω-periodic solutions of R-L fractional derivative-integral equation:is a linear densely defined operator of sectorial type on a completed Banach space X, f is a continuous function satisfying a suitable Lipschitz type condition. We will use the contraction mapping theory to prove problem (1) and (2) has a unique S-asymptotically ω-periodic solution if the function f satisfies Lipshcitz condition.
2012-01-01
We have written a new equation to study the statistics of earthquake distributions. We call this equation "the generalized logistic equation". The Gutenberg-Richter frequency-magnitude formula was derived from the solution of the generalized logistic equation as an asymptotic case in approximation of large magnitudes. To illustrate how the found solution of the generalized logistic equation works, it was used to approximate the observed cumulative distribution of earthquakes in four different...
Directory of Open Access Journals (Sweden)
S. Das
2013-12-01
Full Text Available In this article, optimal homotopy-analysis method is used to obtain approximate analytic solution of the time-fractional diffusion equation with a given initial condition. The fractional derivatives are considered in the Caputo sense. Unlike usual Homotopy analysis method, this method contains at the most three convergence control parameters which describe the faster convergence of the solution. Effects of parameters on the convergence of the approximate series solution by minimizing the averaged residual error with the proper choices of parameters are calculated numerically and presented through graphs and tables for different particular cases.
Investigation on inhibition behavior of S-triazole-triazole derivatives in acidic solution
International Nuclear Information System (INIS)
Four main methods, such as weight loss test, EIS, adsorption isotherm and quantum chemical calculation were employed to study the inhibition efficiency and mechanism of three derivatives on mild steel in acid solution, whose inhibition efficiency were proved to follow the order of DMTT > NMTT > PMTT. The adsorption model of DMTT was established at different temperature according to the fitted results. The quantum chemical results indicated that the adsorption sites of the derivatives were strongly centralized on benzene ring, triazole ring, etc. QSAR was set up to explain the relationship of molecular structure and the inhibition effect of the derivatives
Enzyme stabilization by glass-derived silicates in glass-exposed aqueous solutions
Ives, J.A.; Moffett, J.R.; Arun, P.; Lam, D.; Todorov, T.I.; Brothers, A.B.; Anick, D.J.; Centeno, J.; Namboodiri, M.A.A.; Jonas, W.B.
2010-01-01
Objectives: To analyze the solutes leaching from glass containers into aqueous solutions, and to show that these solutes have enzyme activity stabilizing effects in very dilute solutions. Methods: Enzyme assays with acetylcholine esterase were used to analyze serially succussed and diluted (SSD) solutions prepared in glass and plastic containers. Aqueous SSD preparations starting with various solutes, or water alone, were prepared under several conditions, and tested for their solute content and their ability to affect enzyme stability in dilute solution. Results: We confirm that water acts to dissolve constituents from glass vials, and show that the solutes derived from the glass have effects on enzymes in the resultant solutions. Enzyme assays demonstrated that enzyme stability in purified and deionized water was enhanced in SSD solutions that were prepared in glass containers, but not those prepared in plastic. The increased enzyme stability could be mimicked in a dose-dependent manner by the addition of silicates to the purified, deionized water that enzymes were dissolved in. Elemental analyses of SSD water preparations made in glass vials showed that boron, silicon, and sodium were present at micromolar concentrations. Conclusions: These results show that silicates and other solutes are present at micromolar levels in all glass-exposed solutions, whether pharmaceutical or homeopathic in nature. Even though silicates are known to have biological activity at higher concentrations, the silicate concentrations we measured in homeopathic preparations were too low to account for any purported in vivo efficacy, but could potentially influence in vitro biological assays reporting homeopathic effects. ?? 2009 The Faculty of Homeopathy.
Real analytic quasi-periodic solutions for the derivative nonlinear Schrödinger equations
Geng, Jiansheng; Wu, Jian
2012-10-01
In this paper, we show that one dimension derivative nonlinear Schrödinger equation admits a whitney smooth family of small amplitude, real analytic quasi-periodic solutions with two Diophantine frequencies. The proof is based on a partial Birkhoff normal form reduction and an abstract infinite dimensional Kolmogorov-Arnold-Moser (KAM) theorem.
Existence of solutions and positive solutions to a fourth-order two-point BVP with second derivative
Institute of Scientific and Technical Information of China (English)
姚庆六
2004-01-01
Several existence theorems were established for a nonlinear fourth-order two-point boundary value problem with second derivative by using Leray-Schauder fixed point theorem, equivalent norm and technique on system of integral equations. The main conditions of our results are local. In other words, the existence of the solution can be determined by considering the "height" of the nonlinear term on a bounded set. This class of problems usually describes the equilibrium state of an elastic beam which is simply supported at both ends.
International Nuclear Information System (INIS)
The quasistationary derivatives method is applied in the paper to improve efficiency of numerical algorithms used for calculating analytical solutions of spatial kinetics problems. A one-dimensional problem (BSS-6) published in the ANL Benchmark Problem Book is considered. According to the approach used by the authors of BSS-6, the system of reactor kinetics equations is presented by a system of ordinary differential equations (ODE) obtained after approximation of the diffusion operator by a finite-difference scheme, thus the analytical solution is calculated on the basis of the solution of the full eigenvalue problem. The difficulty is that the matrix of this stiff system is ill-conditioned, therefore standard subroutines for solving problems of linear algebra appear to be unstable numerically here because of the round-off error. The quasistationary derivatives method is used as a preconditioning procedure to diminish the condition number of the system matrix. (author)
On the analytical solution of Fornberg–Whitham equation with the new fractional derivative
Indian Academy of Sciences (India)
Olaniyi Samuel Iyiola; Gbenga Olayinka Ojo
2015-10-01
Motivated by the simplicity, natural and efficient nature of the new fractional derivative introduced by R Khalil et al in J. Comput. Appl. Math. 264, 65 (2014), analytical solution of space-time fractional Fornberg–Whitham equation is obtained in series form using the relatively new method called q-homotopy analysis method (q-HAM). The new fractional derivative makes it possible to introduce fractional order in space to the Fornberg–Whitham equation and be able to obtain its solution. This work displays the elegant nature of the application of q-HAM to solve strongly nonlinear fractional differential equations. The presence of the auxiliary parameter h helps in an effective way to obtain better approximation comparable to exact solutions. The fraction-factor in this method gives it an edge over other existing analytical methods for nonlinear differential equations. Comparisons are made on the existence of exact solutions to these models. The analysis shows that our analytical solutions converge very rapidly to the exact solutions.
A formal derivation for the Blasius similarity solution for flat-plate boundary layer
Lin, Hao
2015-11-01
The Blasius solution is a classical solution for a laminar boundary layer attached to a semi-infinite flat plate. The key of the solution strategy is to reduce the boundary layer equations, which are PDEs, to a set of ODEs, using a similarity variable transform. Conceptually, the similarity suggests that the velocity profile in each transverse cross-section appears ``self-similar''. In many classical text books and typical classroom lectures on fluid mechanics, the existence of the similarity solution is argued heuristically. The similarity variable is defined a priori so as to collapse the PDEs. It appears somewhat mystical that the PDEs can be perfectly reduced via such an approach. Here we present a rigorous derivation for the existence of a similarity solution, which naturally arises from the fact that there is no apparent streamwise length scale for a semi-infinite plate. Conversely, a similarity solution cannot exist if the plate size is finite. This derivation can be useful in fluids education, in topics including similarity, scaling arguments, and boundary layer theory.
Metabolic engineering of yeast to produce fatty acid-derived biofuels: bottlenecks and solutions.
Sheng, Jiayuan; Feng, Xueyang
2015-01-01
Fatty acid-derived biofuels can be a better solution than bioethanol to replace petroleum fuel, since they have similar energy content and combustion properties as current transportation fuels. The environmentally friendly microbial fermentation process has been used to synthesize advanced biofuels from renewable feedstock. Due to their robustness as well as the high tolerance to fermentation inhibitors and phage contamination, yeast strains such as Saccharomyces cerevisiae and Yarrowia lipolytica have attracted tremendous attention in recent studies regarding the production of fatty acid-derived biofuels, including fatty acids, fatty acid ethyl esters, fatty alcohols, and fatty alkanes. However, the native yeast strains cannot produce fatty acids and fatty acid-derived biofuels in large quantities. To this end, we have summarized recent publications in this review on metabolic engineering of yeast strains to improve the production of fatty acid-derived biofuels, identified the bottlenecks that limit the productivity of biofuels, and categorized the appropriate approaches to overcome these obstacles. PMID:26106371
Substituent effect on photophysical properties of bi-1,3,4-oxadiazole derivatives in solution
Chen, Fangyi; Tian, Taiji; Zhao, Chengxiao; Bai, Binglian; Li, Min; Wang, Haitao
2016-04-01
A series of phenyl substituted bi-1,3,4-oxadiazole derivatives were designed and synthesized; the effect of substituent on the photophysical properties and molecular electronic structures was fully studied by the combination of experimental techniques and theoretical calculations. Compared to parent compound without any substituent (BOXD), fluoro-substituent shows little effect on the absorption and emission spectra, whilst a little larger spectral red-shift could be observed for methoxy-, nitro-substituted derivatives and thienyl-substituted bi-1,3,4-oxadiazole (TBOXD). These spectral changes can be well explained by theoretically calculated HOMO and LUMO energy level changes. All these molecules show high fluorescence quantum yield except for nitro-substituted derivative in dilute solutions. The quantum yield of BOXD changes with the concentration and exhibits a high value at the concentrated solution. This work revealed the influence of substituent on the photophysical properties of bi-1,3,4-oxadizaole derivatives in dilute solutions and provided guidance for designing molecules with potential application.
Energy Technology Data Exchange (ETDEWEB)
Cosman, M.; Patel, D.J. [Memorial Sloan Kettering Cancer Center, New York, NY (United States). Cellular Biochemistry and Biophysics Program; Hingerty, B.E. [Oak Ridge National Lab., TN (United States). Health and Safety Research Div.; Amin, S. [American Health Foundation, Valhalla, NY (United States); Broyde, S.; Geacintov, N.E. [New York Univ., NY (United States)
1995-12-31
Site-specifically modified oligonucleotides were derived from the reactions of stereoisomeric polycyclic aromatic diol epoxide metabolite model compounds with oligonucleotides of defined base composition and sequence. The NMR solution structures of ten different adducts studied so far are briefly described, and it is shown that stereochemical factors and the nature of the oligonucleotide context of the complementary strands, exert a powerful influence on the conformational features of these adducts.
Use of Hydrazone Derivates as Inhibitors for the Corrosion of Nickel in Hydrochloric Acid Solution
A.S. Fouda, H. A. Mostafa, S. E. Ghazy and S. A. El- Farah
2007-01-01
The influence of hydrazone derivatives on the corrosion of nickel in 2 mol L-1 hydrochloric acid solution has been studied using weight loss and galvanostatic polarization techniques. In general, at constant acid concentration, the inhibition efficiency increases with increasing the inhibitor concentration and decreases with increasing temperature. Polarization studies indicate that the compounds act as mixed- type inhibitors. The addition of iodide ions enhances the inhibition efficiency to ...
ÇATAV, Şükrü Serter; BEKAR, İsmail; ATEŞ, Büşra Seda; ERGAN, Gökhan; OYMAK, Funda; ÜLKER, Elif Deniz; TAVŞANOĞLU, Çağatay
2012-01-01
The role of smoke as a fire-related germination cue is well known in many parts of the world, including Mediterranean-type ecosystems; however, it has been neglected in the Mediterranean Basin (MB). We studied the germination response of 5 woody species found in the eastern MB (south-western Turkey) to smoke solutions derived from different plant species. Of the 5 species examined, 2 [Sarcopoterium spinosum (L.) Spach and Satureja thymbra L.] showed significant increments in germination perce...
Anti-de Sitter-wave solutions of higher derivative theories.
Gürses, Metin; Hervik, Sigbjørn; Şişman, Tahsin Çağrı; Tekin, Bayram
2013-09-01
We show that the recently found anti-de Sitter (AdS)-plane and AdS-spherical wave solutions of quadratic curvature gravity also solve the most general higher derivative theory in D dimensions. More generally, we show that the field equations of such theories reduce to an equation linear in the Ricci tensor for Kerr-Schild spacetimes having type-N Weyl and type-N traceless Ricci tensors. PMID:25166648
International Nuclear Information System (INIS)
Highlights: • 4-PPM and 5-PPM are new good inhibitors for steel in HCl solution. • Inhibition efficiency follows the order: 4-PPM > 5-PPM. • The adsorption of phenylpyrimidine inhibitor obeys Langmuir adsorption isotherm. • There is a correlation between quantum chemical parameters and inhibition action. • 4-PPM and 5-PPM molecules adsorb on Fe (0 0 1) surface in the nearly flat manner. - Abstract: The inhibition effect of two phenylpyrimidine derivatives of 4-phenylpyrimidine (4-PPM) and 5-phenylpyrimidine (5-PPM) on the corrosion of cold rolled steel (CRS) in HCl solution was studied by weight loss, polarization curves, electrochemical impedance spectroscopy (EIS) and scanning electron microscope (SEM) methods. Quantum chemical calculation and molecular dynamics (MD) were applied to theoretically determine the relationship between molecular structure and inhibition efficiency. The results show that two phenylpyrimidine derivatives are good inhibitors, and inhibition efficiency follows the order: 4-PPM > 5-PPM. The adsorption of each inhibitor on steel surface obeys Langmuir adsorption isotherm. Two phenylpyrimidine derivatives act as mixed-type inhibitors
Inhibition effect of two mercaptopyrimidine derivatives on cold rolled steel in HCl solution
International Nuclear Information System (INIS)
Highlights: • AHMP and DHMP are good mixed-type inhibitors for steel in HCl solution. • AHMP exhibits better inhibitive ability than DHMP. • Inhibition efficiency remains constant from 6 to 156 h. • N8 and O9 atoms of AHMP exhibits more active than those of DHMP. • AHMP and DHMP molecules adsorb on Fe (0 0 1) surface with a nearby flat orientation. - Abstract: The inhibition effect of two mercaptopyrimidine derivatives of 4-amino-6-hydroxy-2-mercaptopyrimidine (AHMP) and 4,6-dihydroxy-2-mercaptopyrimidine (DHMP) on cold rolled steel (CRS) in HCl solution was studied by weight loss, potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS), scanning electron microscope (SEM), quantum chemical calculation and molecular dynamics (MD) simulations methods. The results show that both mercaptopyrimidine derivatives act as good inhibitors, and inhibition efficiency follows the order: AHMP > DHMP. The adsorption of either inhibitor on steel surface obeys Langmuir adsorption isotherm. Two mercaptopyrimidine derivatives are mixed-type inhibitors. The inhibitor molecules adsorb on the Fe (0 0 1) surface in the nearly flat manner
SANS structural characterization of fullerenol-derived star polymers in solutions
Jeng, U S; Wang, L Y; Chiang, L Y; Ho, D L; Han, C C
2002-01-01
We have studied the chain conformations of fullerenol-derived star polymers in two organic solvents using small-angle neutron scattering (SANS). The SANS results indicate that the six poly(urethane-ether) arms, chemically bonded on the fullerenol of the C sub 6 sub 0 -based star polymer, have a Gaussian chain conformation in toluene. However, these arms exhibit a pronounced excluded-volume effect in dimethylformamide solutions. We use a scattering model, with the polydispersity of the polymer taken into account, and a fractal model to extract the radius of gyration R sub g values and the persistence lengths of the C sub 6 sub 0 -star polymers in these two organic solutions. (orig.)
Sorption of copper onto low molecular weight chitosan derivative from aqueous solution.
Boamah, Peter Osei; Huang, Yan; Hua, Mingqing; Onumah, Jacqueline; Sam-Amoah, Livingstone K; Boamah, Paul Osei; Qian, Yaao; Zhang, Qi
2016-07-01
In this study, sorption of copper onto low molecular weight chitosan derivative was studied. Experimental parameters such as pH of the solution (A), temperature (B), dose of the sorbent (C), and concentration of solution (D) were considered. The statistical results indicated that the dose of sorbent (C) and Cu (II) concentration (D) influenced removal efficiency at 5% significance level. Also, some interactions such as ABCD, ACD, ABC and AC affected the removal process. The sorbent was characterized with FTIR, SEM and TG/DSC. Freundlich isotherm model was the best isotherm model. The kinetic study results correlated well with the pseudo-second-order model. The thermodynamic studies revealed that the nature of copper sorption was spontaneous and endothermic. Strong affinity of the sorbent for copper (II) was revealed by the Isothermal Titration Calorimetry (ITC) technique. PMID:27039244
SANS structural characterization of fullerenol-derived star polymers in solutions
Energy Technology Data Exchange (ETDEWEB)
Jeng, U.S.; Lin, T.L. [Department of Engineering and System Science, National Tsing-Hua University, Hsinchu 30043 (Taiwan); Wang, L.Y.; Chiang, L.Y. [Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617 (Taiwan); Ho, D.L.; Han, C.C. [National Institute of Standards and Technology, Gaithersburg, MD 02899 (United States)
2002-07-01
We have studied the chain conformations of fullerenol-derived star polymers in two organic solvents using small-angle neutron scattering (SANS). The SANS results indicate that the six poly(urethane-ether) arms, chemically bonded on the fullerenol of the C{sub 60}-based star polymer, have a Gaussian chain conformation in toluene. However, these arms exhibit a pronounced excluded-volume effect in dimethylformamide solutions. We use a scattering model, with the polydispersity of the polymer taken into account, and a fractal model to extract the radius of gyration R{sub g} values and the persistence lengths of the C{sub 60}-star polymers in these two organic solutions. (orig.)
Structure of leech derived tryptase inhibitor (LDTI-C) in solution.
Mühlhahn, P; Czisch, M; Morenweiser, R; Habermann, B; Engh, R A; Sommerhoff, C P; Auerswald, E A; Holak, T A
1994-12-01
The three-dimensional solution structure of the leech derived tryptase inhibitor form C (LDTI-C), an inhibitor of 46 amino acids which contains 3 disulfide bridges, has been determined using 2D NMR spectroscopy. The 3D structure was determined on the basis of 262 interresidue interproton distance constraints derived from nuclear Overhauser enhancement measurements and 25 phi angles, supplemented by 3 psi and 15 chi 1 angles. The core of LDTI-C is very well defined and consists of a short 3(10)-helix-loop and a short two-stranded antiparallel beta-sheet between residues 13-14 and 20-21. The N-terminus is fixed to the core by two disulfide bridges, while the C-terminus is connected to the beta-sheet via the third disulfide bridge. The binding loop in LDTI exhibits lowest energy conformations belonging to the canonical conformation of serine proteinase inhibitors. PMID:7988692
Benzimidazole and its derivatives as corrosion inhibitors for mild steel in 1M HCl solution
International Nuclear Information System (INIS)
In this paper, the inhibition ability of benzimidazole and its derivatives against the corrosion of mild steel in 1M HCl solution was studied. The change of impedance parameters observed by variation of inhibitors concentration within the range of 50-250 ppm was an indication of their adsorption. The thermodynamic adsorption parameters proposed that these inhibitors retard both cathodic and anodic processes through physical adsorption and blocking the active corrosion sites. The adsorption of these compounds obeyed the Langmuir's adsorption isotherm. The inhibition efficiency was increased with inhibitor concentration in the order of 2-mercaptobenzimidazole > 2-methylbenzimidazole > benzimidazole, which is in accordance with the variation of apparent activation energy of corrosion.
International Nuclear Information System (INIS)
The influence of concentration of particular reagents on the kinetics of Ce(IV) reduction by 2,6-dimethyl and 3,5-dimethyl-anisole as well as 2-methoxy-5-methyl- and 4-methoxy-2-methyl-aniline in perchloric acid solution was investigated, establishing the stoichiometry of these processes. Some intermediate products - macromolecular, derivatives of p-benzoquinone and 4,4'-diphenoquinone - were separated and identified. The effects of substituents and the conditions of performed oxidation processes on the kind and yields of the resultant products were considered. (author). 22 refs, 1 fig., 1 tab
Determination of U(VI) and Pu(IV) in nitric acid solutions with derivative spectroscopy
International Nuclear Information System (INIS)
The authors study the absorption spectra and fourth derivative spectra (FDS) of U(VI) and Pu(IV) in nitric acid solutions and the effect of impurities on FDS. The concentrations of U(VI) and Pu(IV) with peak-zero method at 415 nm and peak-area method between 472.5-479.5 nm are determined, respectively. When CHNO3 or CNO3- is in 1.5-3.0 mol/l, U(VI) can be directly determined by FDS, with the analysis deviation -4 mol/l
Use of Hydrazone Derivates as Inhibitors for the Corrosion of Nickel in Hydrochloric Acid Solution
Directory of Open Access Journals (Sweden)
A.S. Fouda, H. A. Mostafa, S. E. Ghazy and S. A. El- Farah
2007-02-01
Full Text Available The influence of hydrazone derivatives on the corrosion of nickel in 2 mol L-1 hydrochloric acid solution has been studied using weight loss and galvanostatic polarization techniques. In general, at constant acid concentration, the inhibition efficiency increases with increasing the inhibitor concentration and decreases with increasing temperature. Polarization studies indicate that the compounds act as mixed- type inhibitors. The addition of iodide ions enhances the inhibition efficiency to a considerable extent .The effect of temperature on corrosion inhibition has been studied and activation energy has been calculated. Some thermodynamic parameters are calculated and discussed.
Metabolic Engineering of Yeast to Produce Fatty Acid-derived Biofuels: Bottlenecks and Solutions
Directory of Open Access Journals (Sweden)
Jiayuan eSheng
2015-06-01
Full Text Available Fatty acid-derived biofuels can be a better solution than bioethanol to replace petroleum fuel, since they have similar energy content and combustion properties as current transportation fuels. The environmentally friendly microbial fermentation process has been used to synthesize advanced biofuels from renewable feedstock. Due to their robustness as well as the high tolerance to fermentation inhibitors and phage contamination, yeast strains such as Saccharomyces cerevisiae and Yarrowia lipolytica have attracted tremendous attention in recent studies regarding the production of fatty acid-derived biofuels, including fatty acids, fatty acid ethyl esters, fatty alcohols, and fatty alkanes. However, the native yeast strains cannot produce fatty acids and fatty acid-derived biofuels in large quantities. To this end, we have summarized recent publications in this review on metabolic engineering of yeast strains to improve the production of fatty acid-derived biofuels, identified the bottlenecks that limit the productivity of biofuels, and categorized the appropriate approaches to overcome these obstacles.
Numerical solution of the exterior oblique derivative BVP using the direct BEM formulation
Čunderlík, Róbert; Špir, Róbert; Mikula, Karol
2016-04-01
The fixed gravimetric boundary value problem (FGBVP) represents an exterior oblique derivative problem for the Laplace equation. A direct formulation of the boundary element method (BEM) for the Laplace equation leads to a boundary integral equation (BIE) where a harmonic function is represented as a superposition of the single-layer and double-layer potential. Such a potential representation is applied to obtain a numerical solution of FGBVP. The oblique derivative problem is treated by a decomposition of the gradient of the unknown disturbing potential into its normal and tangential components. Our numerical scheme uses the collocation with linear basis functions. It involves a triangulated discretization of the Earth's surface as our computational domain considering its complicated topography. To achieve high-resolution numerical solutions, parallel implementations using the MPI subroutines as well as an iterative elimination of far zones' contributions are performed. Numerical experiments present a reconstruction of a harmonic function above the Earth's topography given by the spherical harmonic approach, namely by the EGM2008 geopotential model up to degree 2160. The SRTM30 global topography model is used to approximate the Earth's surface by the triangulated discretization. The obtained BEM solution with the resolution 0.05 deg (12,960,002 nodes) is compared with EGM2008. The standard deviation of residuals 5.6 cm indicates a good agreement. The largest residuals are obviously in high mountainous regions. They are negative reaching up to -0.7 m in Himalayas and about -0.3 m in Andes and Rocky Mountains. A local refinement in the area of Slovakia confirms an improvement of the numerical solution in this mountainous region despite of the fact that the Earth's topography is here considered in more details.
Institute of Scientific and Technical Information of China (English)
QIANG Ji-Ye; FEI Jin-Xi; CAI Gui-Ping; ZHENG Chun-Long
2007-01-01
With the aid of an improved projective approach and a linear variable separation method,new types of variable separation solutions (including solitary wave solutions,periodic wave solutions,and rational function solutions)with arbitrary functions for (2+1)-dimensional Korteweg-de Vries system are derived.Usually,in terms of solitary wave solutions and rational function solutions,one can find some important localized excitations.However,based on the derived periodic wave solution in this paper,we find that some novel and significant localized coherent excitations such as dromions,peakons,stochastic fractal patterns,regular fractal patterns,chaotic line soliton patterns as well as chaotic patterns exist in the KdV system as considering appropriate boundary conditions and/or initial qualifications.
Ammi, Moulay Rchid Sidi
2011-01-01
In this work we study a generalized nonlocal thermistor problem with fractional-order Riemann-Liouville derivative. Making use of fixed-point theory, we obtain existence and uniqueness of a positive solution.
Trombetta, Mark; Julian, Thomas B.; Wickerham, D. Lawrence; Steed, David L.
2015-01-01
Objective: To establish a safety profile for amnion-derived cellular cytokine solution following topical application in patients undergoing whole breast radiotherapy for breast cancer. Materials and Methods: Twenty female patients with early-stage breast cancer were enrolled in 2 separate cohorts of an institutional review board–approved phase I protocol. Cohort 1 consisted of 10 patients who received topical amnion-derived cellular cytokine solution to the breast immediately following the fi...
Technique for Calculating Solution Derivatives With Respect to Geometry Parameters in a CFD Code
Mathur, Sanjay
2011-01-01
A solution has been developed to the challenges of computation of derivatives with respect to geometry, which is not straightforward because these are not typically direct inputs to the computational fluid dynamics (CFD) solver. To overcome these issues, a procedure has been devised that can be used without having access to the mesh generator, while still being applicable to all types of meshes. The basic approach is inspired by the mesh motion algorithms used to deform the interior mesh nodes in a smooth manner when the surface nodes, for example, are in a fluid structure interaction problem. The general idea is to model the mesh edges and nodes as constituting a spring-mass system. Changes to boundary node locations are propagated to interior nodes by allowing them to assume their new equilibrium positions, for instance, one where the forces on each node are in balance. The main advantage of the technique is that it is independent of the volumetric mesh generator, and can be applied to structured, unstructured, single- and multi-block meshes. It essentially reduces the problem down to defining the surface mesh node derivatives with respect to the geometry parameters of interest. For analytical geometries, this is quite straightforward. In the more general case, one would need to be able to interrogate the underlying parametric CAD (computer aided design) model and to evaluate the derivatives either analytically, or by a finite difference technique. Because the technique is based on a partial differential equation (PDE), it is applicable not only to forward mode problems (where derivatives of all the output quantities are computed with respect to a single input), but it could also be extended to the adjoint problem, either by using an analytical adjoint of the PDE or a discrete analog.
International Nuclear Information System (INIS)
Most of thermal hydraulic processes in nuclear engineering can be described by general convection-diffusion equations that are often can be simulated numerically with finite-difference method (FDM). An effective scheme for finite-difference discretization of such equations is presented in this report. The derivation of this scheme is based on analytical solutions of a simplified one-dimensional equation written for every control volume of the finite-difference mesh. These analytical solutions are constructed using linearized representations of both diffusion coefficient and source term. As a result, the Efficient Finite-Differencing (EFD) scheme makes it possible to significantly improve the accuracy of numerical method even using mesh systems with fewer grid nodes that, in turn, allows to speed-up numerical simulation. EFD has been carefully verified on the series of sample problems for which either analytical or very precise numerical solutions can be found. EFD has been compared with other popular FDM schemes including novel, accurate (as well as sophisticated) methods. Among the methods compared were well-known central difference scheme, upwind scheme, exponential differencing and hybrid schemes of Spalding. Also, newly developed finite-difference schemes, such as the the quadratic upstream (QUICK) scheme of Leonard, the locally analytic differencing (LOAD) scheme of Wong and Raithby, the flux-spline scheme proposed by Varejago and Patankar as well as the latest LENS discretization of Sakai have been compared. Detailed results of this comparison are given in this report. These tests have shown a high efficiency of the EFD scheme. For most of sample problems considered EFD has demonstrated the numerical error that appeared to be in orders of magnitude lower than that of other discretization methods. Or, in other words, EFD has predicted numerical solution with the same given numerical error but using much fewer grid nodes. In this report, the detailed
Solid-State and Solution Structures of Glycinimine-Derived Lithium Enolates.
Jin, Kyoung Joo; Collum, David B
2015-11-18
A combination of crystallographic, spectroscopic, and computational studies was applied to study the structures of lithium enolates derived from glycinimines of benzophenone and (+)-camphor. The solvents examined included toluene and toluene containing various concentrations of tetrahydrofuran, N,N,N',N'-tetramethylethylenediamine (TMEDA), (R,R)-N,N,N',N'-tetramethylcyclohexanediamine [(R,R)-TMCDA], and (S,S)-N,N,N',N'-tetramethylcyclohexanediamine [(S,S)-TMCDA]. Crystal structures show chelated monomers, symmetric disolvated dimers, S4-symmetric tetramers, and both S6- and D3d-symmetric hexamers. (6)Li NMR spectroscopic studies in conjunction with the method of continuous variations show how these species distribute in solution. Density functional theory computations offer insights into experimentally elusive details. PMID:26554898
International Nuclear Information System (INIS)
Fibroblast growth factors (FGFs) bind to extracellular matrices, especially heparin-like carbohydrates of heparansulfate proteoglycans which stabilize FGFs to protect against inactivation by heat, acid, proteolysis and oxidation. Moreover, binding of FGFs to cell surface proteoglycans promotes to form oligomers, which is essential for receptor oligomerization and activation. In the present study, we determined the solution structure of acidic FGF using a series of triple resonance multi-dimensional NMR experiments and simulated annealing calculations. Furthermore, we prepared the sample complexed with a heparin-derived hexasaccharide which is a minimum unit for aFGF binding. From the chemical shift differences between free aFGF and aFGF-heparin complex, we concluded that the major heparin binding site was located on the regions 110-131 and 17-21. The binding sites are quite similar to those observed for bFGF-heparin hexasaccharide complex, showing that both FGFs recognize heparin- oligosaccharides in a similar manner
Chemical solution derived planarization layers for highly aligned IBAD-MgO templates
International Nuclear Information System (INIS)
The main goal of this research is to develop a chemical solution derived planarization layer to fabricate highly aligned IBAD-MgO templates for the development of high temperature superconductor (HTS) based coated conductors. The standard IBAD-MgO template needs an additional electrochemical polishing step of the mechanically polished 50 μm-thick Hastelloy C-276 substrates to ensure a flat and smooth surface for subsequent growth of multi-layer buffer architectures, which include: sputtered 80 nm Al2O3; sputtered 7 nm Y2O3; IBAD 10 nm MgO; sputtered 30 nm homo-epi MgO; and sputtered 30 nm LaMnO3 (LMO) layers. We have successfully developed a solution planarization layer that removes the electrochemical polishing step and also acts as a barrier layer. Crack-free, smooth Al2O3 layers were prepared on mechanically polished Hastelloy substrates using a chemical solution process. The average surface roughness value, Ra, for a starting substrate was 9–10 nm. After eight coatings of Al2O3 layer, the Ra was reduced to 2 nm. Highly aligned IBAD-MgO layers with out-of-plane and in-plane textures comparable to the standard IBAD-MgO layers were successfully deposited on top of the solution planarization Al2O3 layers with an Y2O3 nucleation layer using a reel-to-reel ion-beam sputtering system. Both homo-epi MgO and LMO layers were subsequently deposited on the IBAD-MgO layers using RF sputtering to complete the buffer stack required for the growth of HTS films. YBa2Cu3O7−δ (YBCO) films with a thickness of 0.8 μm deposited on these IBAD-MgO templates by pulsed laser deposition showed a high self-field critical current density, Jc, of 3.04 MA cm−2 at 77 K and 6.05 MA cm−2 at 65 K. These results demonstrate that a low-cost chemical-solution-based, high-throughput Al2O3 planarization layer can remove the electro-polishing step and replace sputtered Al2O3 layers for the production of high Jc YBCO-coated conductors. (fast track communication)
International Nuclear Information System (INIS)
Here we present characterization of solution and thin film properties of Lissamine rhodamine B sulfonyl didodecyl amine (LRSD), an amphiphilic derivative of rhodamine. LRSD was synthesized by functionalizing Lissamine rhodamine B sulfonyl chloride (LRSC) with didodecylamine via a straightforward sulfonylation reaction. LRSD's long alkane chains make it highly soluble in chloroform, with a marked increase in brightness compared to the starting material. LRSD is shown to form well-defined robust micelles in water, without the addition of a co-surfactant and stable monolayers at the air–water interface. The greater lipophilicity of LRSD also enables doping into non-polar polymeric host matrices such as polystyrene with less aggregation and hence higher fluorescence quantum yield than LRSC or even rhodamine B. The monolayers of LRSD were prepared via Langmuir–Blodgett deposition and showed shifts in the photoluminescence peak from 575 nm to 595 nm, as the surface pressure is varied from 3 mN/m to 11 mN/m. - Highlights: • Lissamine rhodamine B sulfonyl didodecyl amine (LRSD) is soluble in chloroform. • LRSD shows robust quantum yield in solution and as a dopant in thin film. • LRSD is an amphiphilic rhodamine dye that forms compact fluorescent micelles. • LRSD forms a stable isotherm when spread at the air–water interface
Directory of Open Access Journals (Sweden)
Magdalena Grenda
2010-11-01
Full Text Available L’article traite du problème de retouche dans la conservation- restauration du papier, concernant en particulier la retouche tratteggio et ses derivatifs que peuvent être la solution de la réintegration de l’image, non si populaire parmi les restaurateurs du papier. C’était la partie du projet de Maîtrise de l’auteur d’examiner la possibilité de l’usage de retouches comme tratteggio dans la restauration de l’affiche de cinéma polonaise de Stefan Norblin, imprimée en lithographie en couleurs.The article describes issues concerning retouch in paper conservation- restoration with particular consideration of tratteggio retouch and its derivatives as an image reintegration solution, not very popular among paper conservators. It was a part of author’s MA project to examine the possibility of using tratteggio- like retouches during the restoration of 20th century Polish film poster by Stefan Norblin, printed in colour litograph.
Yao, Ying; Gao, Bin; Inyang, Mandu; Zimmerman, Andrew R; Cao, Xinde; Pullammanappallil, Pratap; Yang, Liuyan
2011-06-15
Biochar converted from agricultural residues or other carbon-rich wastes may provide new methods and materials for environmental management, particularly with respect to carbon sequestration and contaminant remediation. In this study, laboratory experiments were conducted to investigate the removal of phosphate from aqueous solution by biochar derived from anaerobically digested sugar beet tailings (DSTC). Batch adsorption kinetic and equilibrium isotherm experiments and post-adsorption characterizations using SEM-EDS, XRD, and FTIR suggested that colloidal and nano-sized MgO (periclase) particles on the biochar surface were the main adsorption sites for aqueous phosphate. Batch adsorption experiments also showed that both initial solution pH and coexisting anions could affect the adsorption of phosphate onto the DSTC biochar. Of the mathematical models used to describe the adsorption kinetics of phosphate removal by the biochar, the Ritchie N_th-order (N=1.14) model showed the best fit. Two heterogeneous isotherm models (Freundlich and Langmuir-Freundlich) fitted the experimental isotherm of phosphate adsorption onto the biochar better than the Langmuir adsorption model. Our results suggest that biochar converted from anaerobically digested sugar beet tailings is a promising alternative adsorbent, which can be used to reclaim phosphate from water or reduce phosphate leaching from fertilized soils. In addition, there is no need to regenerate the exhausted biochar because the phosphate-laden biochar contains abundance of valuable nutrients, which may be used as a slow-release fertilizer to enhance soil fertility and to sequester carbon. PMID:21497441
Liu, Mingyue; Li, Ming-De; Huang, Jinqing; Li, Tianlu; Liu, Han; Li, Xuechen; Phillips, David Lee
2016-02-01
Photodeprotection is an important reaction that has been attracting broad interest for use in a variety of applications. Recent advances in ultrafast and vibrational time-resolved spectroscopies can facilitate obtaining data to help unravel the reaction mechanisms involving in the photochemical reactions of interest. The kinetics and reaction mechanisms for the photodeprotection reactions of ketoprofen derivatives containing three different substituents (ibuprofen, Br and I) were investigated by femtosecond transient absorption (fs-TA) and nanosecond time-resolved resonance Raman (ns-TR3) spectroscopy methods in phosphate buffered solutions (PBS). Fs-TA allows us to detect the decay kinetics of the triplet species as the key precursor for formation of a carbanion species for three different substituents attached to ketoprofen. To characterize the structural and electronic properties of the corresponding carbanion and triplet intermediates, TR3 spectroscopic experiments were conducted. The transient spectroscopy work reveals that the different substituents affect the photodecarboxylation reaction to produce carbon dioxide which in turn influences the generation of the carbanion species which determines the rate of the photorelease of the functional groups attached on the ketoprofen parent molecule. The fingerprint TR3 spectroscopy results suggest that ketoprofen derivatives may be deactivated to produce a triplet carbanion when increasing the atom mass of the halogen atoms.
Institute of Scientific and Technical Information of China (English)
2008-01-01
Analytical solutions of governing equations of various phenomena have their irre-placeable theoretical meanings. In addition, they can also be the benchmark solu-tions to verify the outcomes and codes of numerical solutions, and even to develop various numerical methods such as their differencing schemes and grid generation skills as well. A hybrid method of separating variables for simultaneous partial differential equation sets is presented. It is proposed that different methods of separating variables for different independent variables in the simultaneous equa-tion set may be used to improve the solution derivation procedure, for example, using the ordinary separating method for some variables and using extraordinary methods of separating variables, such as the separating variables with addition promoted by the first author, for some other variables. In order to prove the ability of the above-mentioned hybrid method, a lot of analytical exact solutions of two-buoyancy convection in porous media are successfully derived with such a method. The physical features of these solutions are given.
Institute of Scientific and Technical Information of China (English)
CAI RuiXian; LIU QiBin
2008-01-01
Analytical solutions of governing equations of various phenomena have their irre-placeable theoretical meanings. In addition, they can also be the benchmark solu-tions to verify the outcomes and codes of numerical solutions, and even to develop various numerical methods such as their differencing schemes and grid generation skills as well. A hybrid method of separating variables for simultaneous partial differential equation sets is presented. It is proposed that different methods of separating variables for different independent variables in the simultaneous equa-tion set may be used to improve the solution derivation procedure, for example, using the ordinary separating method for some variables and using extraordinary methods of separating variables, such as the separating variables with addition promoted by the first author, for some other variables. In order to prove the ability of the above-mentioned hybrid method, a lot of analytical exact solutions of two-buoyancy convection in porous media are successfully derived with such a method. The physical features of these solutions are given.
International Nuclear Information System (INIS)
The authors demonstrate a high performance electrically controlled birefringence (ECB) mode with solution-derived La2O3 films at various molar concentrations. Uniform and homogeneous liquid crystal (LC) alignment was spontaneously achieved on the La2O3 films for lanthanum concentrations at ratios greater than and equal to 0.2. A preferred orientation of LC molecules appeared along the filling direction, and the LC alignment was maintained via van der Waals force by nanocrystals of the La2O3 films. The LC alignment mechanism was confirmed by x-ray photoelectron spectroscopy and high-resolution transmission electron microscopy analysis. Superior electro-optical characteristics of the ECB cells constructed with solution-derived La2O3 films were observed, which suggests that the proposed solution-derived La2O3 films have strong potential for use in the production of advanced LC displays
International Nuclear Information System (INIS)
Interaction of native calf thymus DNA (ctDNA) with the actinocin derivatives containing protonated diethylamino groups, dimethylamino groups and unsubstituted amino groups and having different length of the alkyl chain have been studied by the method of viscometry. An anomalous hydrodynamic behavior of solutions of DNA with very low amount of ligands prepared under conditions of semidilute solution was revealed. We assumed that such an anomalous behavior of solutions of DNA complexes with actinocin derivatives associated with the formation of intermolecular crosslinks while the preparation of the complex was in terms of overlapping of macromolecular coils in solution. Comparative study of the hydrodynamic behavior of the DNA complexes with various actinocin structures lead us to the conclusion of the formation of crosslinks by the compounds containing protonated diethylamino groups
International Nuclear Information System (INIS)
The effect of two pyrazole-type organic compounds, namely ethyl 5,5'-dimethyl-1'H-1,3'-bipyrazole-3 carboxylate (P1) and 3,5,5'-trimethyl-1'H-1,3'-bipyrazole (P2) on the corrosion behaviour of steel in 1 M hydrochloric acid (HCl) solution is investigated at 308 K by weight loss measurements, potentiodynamic polarisation and impedance spectroscopy (EIS) methods. The inhibition efficiencies obtained from cathodic Tafel plots, gravimetric and EIS methods are in good agreement. Results obtained show that the compound P2 is the best inhibitor and its efficiency reaches 84% at 10-3 M. Potentiodynamic polarisation studies show that pyrazolic derivatives are cathodic-type inhibitors and these compounds act on the cathodic reaction without changing the mechanism of the hydrogen evolution reaction. The inhibition efficiency of P2 is temperature-dependent in the range from 308 to 353 K and the associated activation energy has been determined. P2 adsorbs on the steel surface according to Langmuir adsorption model. The calculation of the total partial charge of inhibitor atoms is computed
Complex formation between neptunium(V) and various thiosemicarbazide derivatives in aqueous solution
International Nuclear Information System (INIS)
Complex formation between neptunium(V) and various thiosemicarbazide derivatives in solution has been studied spectrophotometrically in the pH range 4-10. Stepwise formation of three types of complexes, with composition NpO2HA, NpO2A-, and NpOHA2-, has been demonstrated with salicylaldehyde thiosemicarbazone (H2L) and salicylaldehyde S-methyl-isothiosemicarbazone (H2Q) at t = 25 +/- 10C and μ = 0.05. The logarithmic stability constants of the first two complexes are 5.14 +/- 0.06, 11.85 +/- 0.04 and 8.42 +/- 0.09, 13.33 +/- 0.015 for H2L and H2Q, respectively; equilibrium constants for the formation of hydroxo complexes of the form NpO2OHL2- and NpO2OHQ2- were also determined, and found to be equal to (2.23 +/-0.37) x 10-5 and (5.02 +/- 0.9) x 10-5, respectively. In the case of S-methyl-N1,N4-bis(salicylidene)isothiosemicarbazide (H2Z), only one type of complex is formed under these experimental conditions, namely, NpO2Z-, with a logarithmic stability constant of 4.78 +/- 0.03. Dissociation constants for H2Q and H2Z were also determined
Curcumin Derivatives as Green Corrosion Inhibitors for α-Brass in Nitric Acid Solution
Fouda, A. S.; Elattar, K. M.
2012-11-01
1,7- Bis-(4-hydroxy-3-methoxy-phenyl)-hepta-1,6-diene-4-arylazo-3,5-dione I-V have been investigated as corrosion inhibitors for α-brass in 2 M nitric acid solution using weight-loss and galvanostatic polarization techniques. The efficiency of the inhibitors increases with the increase in the inhibitor concentration but decreases with a rise in temperature. The conjoint effect of the curcumin derivatives and KSCN has also been studied. The apparent activation energy ( E a*) and other thermodynamic parameters for the corrosion process have also been calculated. The galvanostatic polarization data indicated that the inhibitors were of mixed-type, but the cathode is more polarized than the anode. The slopes of the cathodic and anodic Tafel lines ( b c and b a) are maintained approximately equal for various inhibitor concentrations. However, the value of the Tafel slopes increases together as inhibitor concentration increases. The adsorption of these compounds on α-brass surface has been found to obey the Frumkin's adsorption isotherm. The mechanism of inhibition was discussed in the light of the chemical structure of the undertaken inhibitors.
Franz, Michael G.; Payne, Wyatt G.; Xing, Liyu; Naidu, D. K; Salas, R. E; Marshall, Vivienne S.; Trumpower, C. J; Smith, Charlotte A; Steed, David L.; Robson, M. C.
2008-01-01
Objective: Growth factors demonstrate mixed results improving wound healing. Amnion-derived multipotent cells release physiologic levels of growth factors and tissue inhibitors of metalloproteinases. This solution was tested in models of acute and chronic wound healing. Methods: Acute model: Sprague-Dawley rats underwent laparotomy incisions. The midline fascia was primed with phosphate-buffered saline, unconditioned media, or amnion-derived cellular cytokine suspension prior to incision. Bre...
International Nuclear Information System (INIS)
A globally causal vacuum solution with the symmetries of the Godel universe is obtained in the framework of higher-derivative gravity. This very peculiar and rare result has no similar one in the standard general relativity. The Reboucas-Tiomno universe, i.e., the unique completely causal Goedel-type solution of Einstein's field equations with the algebraic Segre characteristics [(1,11)] is shown to be a special case of our solution. It is also shown that one model is an imbedding of the 3-dimensional anti-de Litter universe in 4-dimensional space-time. (authors)
Systematic vertical error in UAV-derived topographic models: Origins and solutions
James, Mike R.; Robson, Stuart
2014-05-01
Unmanned aerial vehicles (UAVs) equipped with consumer cameras are increasingly being used to produce high resolution digital elevation models (DEMs). However, although such DEMs may achieve centimetric detail, they can also display broad-scale systematic deformation (usually a vertical 'doming') that restricts their wider use. This effect can be particularly apparent in DEMs derived by structure-from-motion (SfM) processing, especially when control point data have not been incorporated in the bundle adjustment process. We illustrate that doming error results from a combination of inaccurate description of radial lens distortion and the use of imagery captured in near-parallel viewing directions. With such imagery, enabling camera self-calibration within the processing inherently leads to erroneous radial distortion values and associated DEM error. Using a simulation approach, we illustrate how existing understanding of systematic DEM error in stereo-pairs (from unaccounted radial distortion) up-scales in typical multiple-image blocks of UAV surveys. For image sets with dominantly parallel viewing directions, self-calibrating bundle adjustment (as normally used with images taken using consumer cameras) will not be able to derive radial lens distortion accurately, and will give associated systematic 'doming' DEM deformation. In the presence of image measurement noise (at levels characteristic of SfM software), and in the absence of control measurements, our simulations display domed deformation with amplitude of ~2 m over horizontal distances of ~100 m. We illustrate the sensitivity of this effect to variations in camera angle and flight height. Deformation will be reduced if suitable control points can be included within the bundle adjustment, but residual systematic vertical error may remain, accommodated by the estimated precision of the control measurements. Doming bias can be minimised by the inclusion of inclined images within the image set, for example
Complex formation between neptunium(V) and various thiosemicarbazide derivatives in aqueous solution
Energy Technology Data Exchange (ETDEWEB)
Chuguryan, D.G.; Dzyubenko, V.I.; Gerbeleu, N.V.
1987-01-01
Complex formation between neptunium(V) and various thiosemicarbazide derivatives in solution has been studied spectrophotometrically in the pH range 4-10. Stepwise formation of three types of complexes, with composition NpO/sub 2/HA, NpO/sub 2/A/sup -/, and NpOHA/sup 2 -/, has been demonstrated with salicylaldehyde thiosemicarbazone (H/sub 2/L) and salicylaldehyde S-methyl-isothiosemicarbazone (H/sub 2/Q) at t = 25 +/- 1/sup 0/C and ..mu.. = 0.05. The logarithmic stability constants of the first two complexes are 5.14 +/- 0.06, 11.85 +/- 0.04 and 8.42 +/- 0.09, 13.33 +/- 0.015 for H/sub 2/L and H/sub 2/Q, respectively; equilibrium constants for the formation of hydroxo complexes of the form NpO/sub 2/OHL/sup 2 -/ and NpO/sub 2/OHQ/sup 2 -/ were also determined, and found to be equal to (2.23 +/-0.37) x 10/sup -5/ and (5.02 +/- 0.9) x 10/sup -5/, respectively. In the case of S-methyl-N/sub 1/,N/sub 4/-bis(salicylidene)isothiosemicarbazide (H/sub 2/Z), only one type of complex is formed under these experimental conditions, namely, NpO/sub 2/Z/sup -/, with a logarithmic stability constant of 4.78 +/- 0.03. Dissociation constants for H/sub 2/Q and H/sub 2/Z were also determined.
Lee, Yun-Gun; Park, Hong-Gyu; Jeong, Hae-Chang; Lee, Ju Hwan; Heo, Gi-Seok; Seo, Dae-Shik
2015-06-29
Solution-derived HfYGaO films have been treated by ion beam (IB) irradiation and used as liquid crystal (LC) alignment layers. Solution processing was adopted due to its simplicity, high throughput, and facile composition modification. Homogeneous and uniform LC alignment was achieved on the IB-irradiated HfYGaO films, and when these films were adopted in twisted nematic (TN) cells, electro-optical performance comparable to that of TN cells with conventional polyimide layers was achieved, with almost no capacitance-voltage hysteresis. Moreover, LC cells based on IB-irradiated HfYGaO films had a high thermal budget. The proposed IB-irradiated solution-derived HfYGaO films have considerable potential for use in advanced LC applications. PMID:26191738
Time-varying gravity comparison of the GSFC solutions derived from DORIS, SLR and GRACE
Chinn, D. S.; Le Bail, K.; Lemoine, F. G.; Beall, J. W.; Luthcke, S. B.; Rowlands, D. D.
2008-12-01
The GRACE gravity mission has now supplied us with solutions for the time variations in the Earth's gravity field that now span more than five years, from 2003 to the present. Solutions are available from different analysis centers: GSFC, CNES, JPL, and UT/CSR. Satellite laser ranging (SLR) and DORIS (Doppler Orbitography and Radiopositioning) Integrated by satellite have also been used to develop time series of geopotential solutions, which describe the low degree variations in the geopotential. In the case of SLR, these data span more than 25 years, and in the case of DORIS the solutions span the past 15 years (since 1993). The SLR satellites that contribute include Lageos1 and Lageos2, Starlette, Stella, Ajisai, and other spacecraft. The DORIS satellites include the full constellation of DORIS spacecraft including TOPEX, ENVISAT, and the SPOT series of satellites. We describe the time series obtained from the various solutions, and examine statistically the similarities and differences between the time series, and the quality of the solutions, and describe the annual and interannual signals that appear in the solutions. We compare the low degree harmonics for the periods where the SLR, DORIS and GRACE time series overlap, and we intercompare the geopotential rate solutions for the three sets of solutions, bearing in mind that the techniques supply solutions over different time periods.
(Anti-) de Sitter Electrically Charged Black Hole Solutions in Higher-Derivative Gravity
Lin, Kai; Qian, Wei-Liang; Pavan, A. B.; Abdalla, E.
2016-01-01
In this paper, static electrically charged black hole solutions with cosmological constant are investigated in an Einstein-Hilbert theory of gravity with additional quadratic curvature terms. Beside the analytic Schwarzschild (Anti-) de Sitter solutions, non-Schwarzschild (Anti-) de Sitter solutions are also obtained numerically by employing the shooting method. The results show that there exist two groups of asymptotically (Anti-) de Sitter spacetimes for both charged and uncharged black hol...
Liimatainen, Henrikki; Sirviö, Juho; Sundman, Ola; Visanko, Miikka; Hormi, Osmo; Niinimäki, Jouko
2011-10-01
The flocculation behavior of cationic, quaternary ammonium groups containing cellulosic biopolymers, CDACs, synthesized by cationizing dialdehyde cellulose in mild aqueous solution was studied in a kaolin suspension. In particular, the role of CDAC dosage and solution pH, NaCl concentration, and temperature were clarified. In addition, the initial apparent charge densities (CDs), particle sizes, ζ-potential, and stability of CDs were determined. CDACs possessed a high flocculation activity in neutral and acidic solutions, but a significant decrease was observed in alkaline solutions (pH >9). This was also seen as a decline in the apparent CD and particle size of the CDACs in alkaline conditions. The measurements also indicated that the apparent CD decreased to a constant level of 3 mmol/g in aqueous solutions. However, no notable decrease in flocculation performance was obtained after several days of storage. Moreover, the variation of NaCl concentration and temperature did not affect the flocculation activity. PMID:21862324
(Anti-) de Sitter Electrically Charged Black Hole Solutions in Higher-Derivative Gravity
Lin, Kai; Pavan, A B; Abdalla, E
2016-01-01
In this paper, static electrically charged black hole solutions with cosmological constant are investigated in an Einstein-Hilbert theory of gravity with additional quadratic curvature terms. Beside the analytic Schwarzschild (Anti-) de Sitter solutions, non-Schwarzschild (Anti-) de Sitter solutions are also obtained numerically by employing the shooting method. The results show that there exist two groups of asymptotically (Anti-) de Sitter spacetimes for both charged and uncharged black holes. In particular, it was found that for uncharged black holes the first group can be reduced to the Schwarzschild (Anti-) de Sitter solution, while the second group is intrinsically different from a Schwarzschild (Anti-) de Sitter solution even when the charge and the cosmological constant become zero.
(Anti-) de Sitter electrically charged black-hole solutions in higher-derivative gravity
Lin, Kai; Qian, Wei-Liang; Pavan, A. B.; Abdalla, E.
2016-06-01
In this paper, static electrically charged black-hole solutions with cosmological constant are investigated in an Einstein-Hilbert theory of gravity with additional quadratic curvature terms. Beside the analytic Schwarzschild (Anti-) de Sitter solutions, non-Schwarzschild (Anti-) de Sitter solutions are also obtained numerically by employing the shooting method. The results show that there exist two groups of asymptotically (Anti-) de Sitter spacetimes for both charged and uncharged black holes. In particular, it was found that for uncharged black holes the first group can be reduced to the Schwarzschild (Anti-) de Sitter solution, while the second group is intrinsically different from a Schwarzschild (Anti-) de Sitter solution even when the charge and the cosmological constant become zero.
Jiang, Shidong; Luo, Li-Shi
2016-07-01
The integral equation for the flow velocity u (x ; k) in the steady Couette flow derived from the linearized Bhatnagar-Gross-Krook-Welander kinetic equation is studied in detail both theoretically and numerically in a wide range of the Knudsen number k between 0.003 and 100.0. First, it is shown that the integral equation is a Fredholm equation of the second kind in which the norm of the compact integral operator is less than 1 on Lp for any 1 ≤ p ≤ ∞ and thus there exists a unique solution to the integral equation via the Neumann series. Second, it is shown that the solution is logarithmically singular at the endpoints. More precisely, if x = 0 is an endpoint, then the solution can be expanded as a double power series of the form ∑n=0∞∑m=0∞cn,mxn(xln x)m about x = 0 on a small interval x ∈ (0 , a) for some a > 0. And third, a high-order adaptive numerical algorithm is designed to compute the solution numerically to high precision. The solutions for the flow velocity u (x ; k), the stress Pxy (k), and the half-channel mass flow rate Q (k) are obtained in a wide range of the Knudsen number 0.003 ≤ k ≤ 100.0; and these solutions are accurate for at least twelve significant digits or better, thus they can be used as benchmark solutions.
Popr, Martin; Filippov, Sergey K; Matushkin, Nikolai; Dian, Juraj; Jindřich, Jindřich
2015-01-01
The thermal stability of the monosubstituted cationic cyclodextrin (CD) derivatives PEMEDA-β-CD and PEMPDA-β-CD, which differ in their substituent linker length (ethylene and propylene, respectively), was studied via (1)H NMR experiments. PEMPDA-β-CD exhibited higher resistance towards the Hofmann degradation and was chosen as a more suitable host molecule for further studies. Inclusion properties of PEMPDA-β-CD in solution with a series of simple aromatic guests (salicylic acid, p-methoxyphenol and p-nitroaniline) were determined by isothermal titration calorimetry (ITC) and compared to the native β-CD. Permanently charged cationic CD derivatives were successfully deposited on the anionic solid surface of polymeric Nafion(®) 117 membrane via electrostatic interactions. Deposition kinetics and coverage of the surface were determined by ELSD. Finally, the ability of the CD derivatives bound to the solid surface to encapsulate aromatic compounds from aqueous solution was measured by UV-vis spectroscopy. The obtained results are promising for future industrial applications of the monosubstituted β-CD derivatives, because the preparation of cationic CD derivatives is applicable in large scale, without the need of chromatographic purification. Their ionic deposition on a solid surface is simple, yet robust and a straightforward process as well. PMID:25815069
Mohammed, K. Elboree
2015-10-01
In this paper, we investigate the traveling wave solutions for the nonlinear dispersive equation, Korteweg-de Vries Zakharov-Kuznetsov (KdV-ZK) equation and complex coupled KdV system by using extended simplest equation method, and then derive the hyperbolic function solutions include soliton solutions, trigonometric function solutions include periodic solutions with special values for double parameters and rational solutions. The properties of such solutions are shown by figures. The results show that this method is an effective and a powerful tool for handling the solutions of nonlinear partial differential equations (NLEEs) in mathematical physics.
Physical Property Modeling of Concentrated Cesium Eluate Solutions, Part I - Derivation of Models
Energy Technology Data Exchange (ETDEWEB)
Choi, A.S.; Pierce, R. A.; Edwards, T. B.; Calloway, T. B.
2005-09-15
Major analytes projected to be present in the Hanford Waste Treatment Plant cesium ion-exchange eluate solutions were identified from the available analytical data collected during radioactive bench-scale runs, and a test matrix of cesium eluate solutions was designed within the bounding concentrations of those analytes. A computer model simulating the semi-batch evaporation of cesium eluate solutions was run in conjunction with a multi-electrolyte aqueous system database to calculate the physical properties of each test matrix solution concentrated to the target endpoints of 80% and 100% saturation. The calculated physical properties were analyzed statistically and fitted into mathematical expressions for the bulk solubility, density, viscosity, heat capacity and volume reduction factor as a function of temperature and concentration of each major analyte in the eluate feed. The R{sup 2} of the resulting physical property models ranged from 0.89 to 0.99.
Edris Hoseinzadeh; Ali Reza Rahmani; Ghorban Asgari; Mohamad Taghi Samadi; Ghodratollah Roshanaei; Mohammad Reza Zare
2013-01-01
Background and Aim: Heavy metals have been recognized as very poisonous elements and their discharge into water sources can cause damaging effects on human and environmental health. The present study aimed at producing activated carbon from scrap tires and using it in removing Pb+2 from synthetic aqueous solutions. Materials and Methods: In this experimental study, activated carbon powder was derived from scrap tires under laboratory conditions. The effect of Pb (II) ions wi...
DEFF Research Database (Denmark)
Paradelo Pérez, Marcos; Katuwal, Sheela; Møldrup, Per;
2016-01-01
The characterization of soil pore space geometry is important for explaining fluxes of air, water, and solutes through soil and understanding soil hydrogeochemical functions. X-ray computed tomography (CT) can be applied for this characterization, and in this study CT-derived parameters were used...... to explain water, air, and solute transport through soil. Forty-five soil columns (20 by 20 cm) were collected from an agricultural field in Estrup, Denmark, and subsequently scanned using a medical CT scanner. Nonreactive tracer leaching experiments were performed in the laboratory along with...... improved when the limiting macroporosity (the minimum macroporosity for every 0.6-mm layer along the soil column) was used, suggesting that soil layers with the narrowest macropore section restricted the flow through the whole soil column. Water, air, and solute transport were related with the CT...
Removal of trivalent samarium from aqueous solutions by activated biochar derived from cactus fibres
Institute of Scientific and Technical Information of China (English)
Loukia Hadjittofi; Styliana Charalambous; Ioannis Pashalidis
2016-01-01
The efficiency of activated biochar fibres obtained fromOpuntia Ficus Indica regarding the sorption of trivalent samarium (Sm(III)) from aqueous solutions was investigated by batch experiments. The effect of various physicochemical parameters (e.g. pH, initial metal concentration, ionic strength, temperature and contact time) on the Sm(III) adsorption was studied and the surface species were characterized by FTIR spectroscopy prior to and after the lanthanide sorption. The experimental results showed that the acti-vated biochar fibres possessed extraordinary sorption capacity for Sm(III) in acidic solutions (qmax=90 g/kg, pH 3.0) and near neutral solutions (qmax=350 g/kg, pH 6.5). This was attributed to the formation of samarium complexes with the surface carboxylic moieties, available in high density on the lamellar structures of the bio-sorbent.
Solutions for the Cell Cycle in Cell Lines Derived from Human Tumors
Directory of Open Access Journals (Sweden)
B. Zubik-Kowal
2006-01-01
Full Text Available The goal of the paper is to compute efficiently solutions for model equations that have the potential to describe the growth of human tumor cells and their responses to radiotherapy or chemotherapy. The mathematical model involves four unknown functions of two independent variables: the time variable t and dimensionless relative DNA content x. The unknown functions can be thought of as the number density of cells and are solutions of a system of four partial differential equations. We construct solutions of the system, which allow us to observe the number density of cells for different t and x values. We present results of our experiments which simulate population kinetics of human cancer cells in vitro. Our results show a correspondence between predicted and experimental data.
Inhibition of the corrosion of carbon steel in HCl solution by methionine and its derivatives
International Nuclear Information System (INIS)
Highlights: • The methionine derivatives were good corrosion inhibitors for 1045 carbon steel (CS). • The XPS indicated that the FMOC self-assembled on CS surface by chemisorption. • The Fukui surface distribution and the radial distribution function were used. - Abstract: The self-assembled films of methionine and its derivatives were prepared on a 1045 carbon steel (CS) surface. EIS and potentiodynamic measurements showed that these films could effectively protect CS against corrosion in 0.5 M HCl, with a maximal protection efficiency of 95.01% achieved by FMOC films. An XPS study confirmed that methionine and its derivatives could form films by chemical adsorption on CS. The inhibition mechanism was theoretically investigated through the quantum chemical calculation and dynamic simulation
Quasi-periodic solutions for d-dimensional beam equation with derivative nonlinear perturbation
Energy Technology Data Exchange (ETDEWEB)
Mi, Lufang, E-mail: milufang@126.com [Department of Mathematics, Binzhou University, Shandong 256600 (China); Cong, Hongzi, E-mail: conghongzi@dlut.edu.cn [School of Mathematical Sciences, Dalian University of Technology, Liaoning 116024 (China)
2015-07-15
In this paper, we consider the d-dimensional beam equation with convolution potential under periodic boundary conditions. We will apply the Kolmogorov-Arnold-Moser theorem in Eliasson and Kuksin [Ann. Math. 172, 371-435 (2010)] into this system and obtain that for sufficiently small ε, there is a large subset S′ of S such that for all s ∈ S′, the solution u of the unperturbed system persists as a time-quasi-periodic solution which has all Lyapunov exponents equal to zero and whose linearized equation is reducible to constant coefficients.
International Nuclear Information System (INIS)
Estimates for generalized solutions of the first boundary value problem for nondivergent parabolic equations with unbounded lower-term coefficients have been obtained. The cases where these coefficients belong to isotropic and anisotropic Lebesgue spaces have been separately considered. The leading coefficients can be discontinuous, but should satisfy the Cordes condition
New solutions of reflection equation derived from type B BMW algebras
Häring-Oldenburg, Reinhard
1996-09-01
We use B-type knot theory to find new solutions of Sklyanin's reflection equation in a systematic way. This generalizes the well known Baxterization of Birman - Wenzl algebras and should describe integrable systems which are restricted to a half plane.
International Nuclear Information System (INIS)
Starting from the radiation transport equation for homogeneous, refractive lossy media, we derive the corresponding time-dependent multifrequency diffusion equations. Zeroth and first moments of the transport equation couple the energy density, flux and pressure tensor. The system is closed by neglecting the temporal derivative of the flux and replacing the pressure tensor by its diagonal analogue. The radiation equations are coupled to a diffusion equation for the matter temperature. We are interested in modeling heating and cooling of silica (SiO2), at possibly rapid rates. Hence, in contrast to related work, we retain the temporal derivative of the radiation field. We derive boundary conditions at a planar air-silica interface taking account of reflectivities obtained from the Fresnel relations that include absorption. The spectral dimension is discretized into a finite number of intervals leading to a system of multigroup diffusion equations. Three simulations are presented. One models cooling of a silica slab, initially at 2500 K, for 10 s. The other two are 1D and 2D simulations of irradiating silica with a CO2 laser, λ = 10.59 μm. In 2D, a laser beam (Gaussian profile, r0 = 0.5 mm for 1/e decay) shines on a disk (radius = 0.4, thickness = 0.4 cm).
International Nuclear Information System (INIS)
The influence of few triazole derivatives namely, 4-amino-5-mercapto-3-methyl 1,2,4 triazole (AMMT), 4-amino-5-mercapto-3-methyl 1,2,4 triazole (AMET) and 4-amino-5-mercapto-3-propyl 1,2,4 triazole (AMPT) on the corrosion behavior of muntz metal (60Cu-40Zn) in acidic and neutral solutions has been studied using weight loss measurements and potentiodynamic polarization methods. Surface morphological examinations such as UV spectral analysis, XRD and SEM have also been carried out to understand the mechanism of inhibition of corrosion. All the triazoles derivatives are found to inhibit the corrosion of muntz metal very effectively in both the acidic and neutral solutions. Polarization measurements clearly show that the inhibitors behave as mixed type in neutral medium and are predominantly cathodic nature in acidic solutions. UV spectra, XRD and Scanning Electron Microscopic studies clearly reveal the formation of a strongly adsorbed film on the metal surface, which is responsible for the inhibition of corrosion in both the media. From the above studies, it can be concluded that the inhibition of corrosion by these compounds is due to a chmisorption process. Among these compounds, AMPT is found to offer better corrosion inhibition than the other compounds
International Nuclear Information System (INIS)
Graphical abstract: -- Highlights: •1,3-Dibenzylthiourea/DBTU and 1-benzyl-3-diisopropylthiourea/DPTU were studied. •DPTU and DBTU act as good corrosion inhibitors for C-steel in acid solution. •The inhibition efficiency of DPTU and DBTU increased with concentration. •DBU did not act as an effective corrosion inhibitor for C-steel in acid solution. •The sulphur atom may play an important role in the inhibition process. -- Abstract: The behaviour of 1,3-dibenzylthiourea (DBTU) and 1-benzyl-3-diisopropylthiourea (DPTU) have been investigated as carbon steel corrosion inhibitors in HCl solution by weight loss measurements, potentiodynamic polarization curves, electrochemical impedance and scanning electron microscopy analysis. Quantum chemical calculation was applied to correlate electronic structure parameters of thiourea derivatives with their inhibition performances. DPTU results were slightly superior to those obtained in the presence of DBTU, showing that the replacement of one benzyl group for two isopropyl groups enhances the inhibitory properties. The 1,3-dibenzylurea derivative has also been studied in order to assess the importance of the sulphur atom to the inhibitory effect
Directory of Open Access Journals (Sweden)
Claus Larsen
2007-10-01
Full Text Available A series of model phenol carbonate ester prodrugs encompassing derivatives with fatty acid-like structures were synthesized and their stability as a function of pH (range 0.4 Ã¢Â€Â“ 12.5 at 37Ã‚Â°C in aqueous buffer solutions investigated. The hydrolysis rates in aqueous solutions differed widely, depending on the selected pro-moieties (alkyl and aryl substituents. The observed reactivity differences could be rationalized by the inductive and steric properties of the substituent groups when taking into account that the mechanism of hydrolysis may change when the type of pro-moiety is altered, e.g. n-alkyl vs. t-butyl. Hydrolysis of the phenolic carbonate ester 2-(phenoxycarbonyloxy-acetic acid was increased due to intramolecular catalysis, as compared to the derivatives synthesized from ÃÂ‰-hydroxy carboxylic acids with longer alkyl chains. The carbonate esters appear to be less reactive towards specific acid and base catalyzed hydrolysis than phenyl acetate. The results underline that it is unrealistic to expect that phenolic carbonate ester prodrugs can be utilized in ready to use aqueous formulations. The stability of the carbonate ester derivatives with fatty acid-like structures, expected to interact with the plasma protein human serum albumin, proved sufficient for further in vitro and in vivo evaluation of the potential of utilizing HSA binding in combination with the prodrug approach for optimization of drug pharmacokinetics.
Energy Technology Data Exchange (ETDEWEB)
Riley, Brian J.; Lepry, William C.; Crum, Jarrod V.
2016-01-01
Chlorosodalite has the general form of Na8(AlSiO4)6Cl2 and this paper describes experiments conducted to synthesize sodalite to immobilize a mixed chloride salt using solution-based techniques. Sodalites were made using different Group IV contributions from either Si(OC2H5)4 or Ge(OC2H5)4, NaAlO2, and a simulated spent electrorefiner salt solution containing a mixture of alkali, alkaline earth, and lanthanide chlorides. Additionally, 6 glass binders at low loadings of 5 mass% were evaluated as sintering aids for the consolidation process. The approach of using the organic Group IV additives can be used to produce large quantities of sodalite at room temperature and shows promise over a method where colloidal silica is used as the silica source. However, the small particle sizes inhibited densification during pressure-less sintering.
Process optimization of solution derived YBa2Cu3O7-x superconducting oxide films
International Nuclear Information System (INIS)
Superconducting YBa2Cu3O7-x films were deposited on LaAlO3 and other single crystal substrates from carboxylate precursor solutions by spin-coating. Films up to 1.5 μm were prepared and fired at 780-950C under controlled ambient. Processing parameters such as temperature, ambient, time, thickness, and substrate were investigated and shown to significantly affect film microstructure and properties. Highly oriented films with Tc(onset) ∼ 90k and Tc(zero) ∼ 86 K were fabricated under near optimized processing conditions. This talk focuses on film thickness and substrate effects on electrical and magnetic properties and also on orientation and interfacial reactions. Understanding and control of these processing parameters are key factors in the fabrication of thin films from solution precursors
Sharp Derivative Bounds for Solutions of Degenerate Semi-Linear Partial Differential Equations
Crisan, Dan; Delarue, François
2012-01-01
The paper is a continuation of the Kusuoka-Stroock programme of establishing smoothness properties of solutions of (possibly) degenerate partial differential equations by using probabilistic methods. We analyze here a class of semi-linear parabolic partial differential equations for which the linear part is a second order differential operator of the form V0+PN i=1 V 2 i , where V0, . . . , VN are first order differential operators that satisfy the so-called UFG condition (see [18]), which is...
Solution structure of a soluble fragment derived from a membrane protein by shotgun proteolysis
Allen, Mark D.; Christie, Mary; Jones, Peter; Porebski, Benjamin T.; Roome, Brendan; Freund, Stefan M V; Buckle, Ashley M.; Bycroft, Mark; Christ, Daniel
2015-01-01
We have previously reported a phage display method for the identification of protein domains on a genome-wide scale (shotgun proteolysis). Here we present the solution structure of a fragment of the Escherichia coli membrane protein yrfF, as identified by shotgun proteolysis, and determined by NMR spectroscopy. Despite the absence of computational predictions, the fragment formed a well-defined beta-barrel structure, distantly falling within the OB-fold classification. Our results highlight t...
Cocco, Simona; Barbi, Maria; Peyrard, Michel
1999-01-01
Group velocity and group velocity dispersion for a wave packet in vectorial discrete Klein-Gordon models are obtained by an expansion, based on perturbation theory, of the linear system giving the dispersion relation and the normal modes. We show how to map this expansion on the Multiple Scale Expansion in the real space and how to find Non Linear Schr\\"odinger small amplitude solutions when a nonlinear one site potential balances the group velocity dispersion effect.
International Nuclear Information System (INIS)
The activated carbons (ACs) prepared from cattle manure compost (CMC) with various pore structure and surface chemistry were used to remove phenol and methylene blue (MB) from aqueous solutions. The adsorption equilibrium and kinetics of two organic contaminants onto the ACs were investigated and the schematic models for the adsorptive processes were proposed. The result shows that the removal of functional groups from ACs surface leads to decreasing both rate constants for phenol and MB adsorption. It also causes the decrement of MB adsorption capacity. However, the decrease of surface functional groups was found to result in the increase of phenol adsorption capacity. In our schematic model for adsorptive processes, the presence of acidic functional groups on the surface of carbon is assumed to act as channels for diffusion of adsorbate molecules onto small pores, therefore, promotes the adsorption rate of both phenol and MB. In phenol solution, water molecules firstly adsorb on surface oxygen groups by H-bonding and subsequently form water clusters, which cause partial blockage of the micropores, deduce electrons from the π-electron system of the carbon basal planes, hence, impede or prevent phenol adsorption. On the contrary, in MB solution, the oxygen groups prefer to combine with MB+ cations than water molecules, which lead to the increase of MB adsorption capacity.
A closed-form solution for the price of cross-commodity electricity derivatives
Tsitakis, D.; Xanthopoulos, S.; Yannacopoulos, A. N.
2006-11-01
We present a method for the valuation of two types of cross-commodity electricity options, European spark spread options and locational spread options. Since the underlying assets here are non-tradeable, the methodology of Black-Scholes-Merton cannot be directly applied. Nevertheless, assuming only absence of arbitrage we provide a closed-form analytic formula for the price of the derivatives in the case where the spot prices of the underlying process follow an exponential Ornstein-Uhlenbeck process.
Directory of Open Access Journals (Sweden)
Verena Bongartz
2016-01-01
Full Text Available Sunflower extraction meal (SEM is an economically interesting protein source. During alkaline extraction of proteins, the presence of chlorogenic acid (CQA in the meal gives rise to the formation of o-quinones. Reactions with nucleophiles present in proteins can lead to green discoloration. Although such reactions have been known for a long time, there is a lack of information on the chemical nature of the reaction products. SEM and model systems consisting of amino acids and CQA were subjected to alkaline treatment and, for comparison, to oxidation of CQA by polyphenoloxidase (PPO. Several green trihydroxy benzacridine (TBA derivatives were tentatively identified in all samples by UHPLC-DAD-MS/MS. Surprisingly, in alkaline-treated samples of particular amino acids as well as in SEM, the same six TBA isomers were detected. In contrast, the enzymatically oxidized samples resulted in only three TBA derivatives. Contrary to previous findings, neither peptide nor amino acid residues were attached to the resultant benzacridine core. The results indicate that the formation of TBA derivatives is caused by the reaction between CQA quinones and free NH2 groups. Further research is necessary to elucidate the structure of the addition products for a comprehensive evaluation of food and feed safety aspects.
Bongartz, Verena; Brandt, Lisa; Gehrmann, Mai Linh; Zimmermann, Benno F; Schulze-Kaysers, Nadine; Schieber, Andreas
2016-01-01
Sunflower extraction meal (SEM) is an economically interesting protein source. During alkaline extraction of proteins, the presence of chlorogenic acid (CQA) in the meal gives rise to the formation of o-quinones. Reactions with nucleophiles present in proteins can lead to green discoloration. Although such reactions have been known for a long time, there is a lack of information on the chemical nature of the reaction products. SEM and model systems consisting of amino acids and CQA were subjected to alkaline treatment and, for comparison, to oxidation of CQA by polyphenoloxidase (PPO). Several green trihydroxy benzacridine (TBA) derivatives were tentatively identified in all samples by UHPLC-DAD-MS/MS. Surprisingly, in alkaline-treated samples of particular amino acids as well as in SEM, the same six TBA isomers were detected. In contrast, the enzymatically oxidized samples resulted in only three TBA derivatives. Contrary to previous findings, neither peptide nor amino acid residues were attached to the resultant benzacridine core. The results indicate that the formation of TBA derivatives is caused by the reaction between CQA quinones and free NH2 groups. Further research is necessary to elucidate the structure of the addition products for a comprehensive evaluation of food and feed safety aspects. PMID:26784152
International Nuclear Information System (INIS)
Highlights: • Enthalpies of solution measured for 48 solutes dissolved in mesitylene. • Enthalpies of solution measured for 81 solutes dissolved in p-xylene. • Abraham model correlations derived for enthalpies of solvation of solutes in mesitylene. • Abraham model correlations derived for enthalpies of solvation of solutes in p-xylene. • Hydrogen-bonding enthalpies reported for interactions of aromatic hydrocarbons with hydrogen-bond acidic solutes. - Abstract: Enthalpies of solution at infinite dilution of 48 organic solutes in mesitylene and 81 organic solutes in p-xylene were measured using isothermal solution calorimeter. Enthalpies of solvation for 92 organic vapors and gaseous solutes in mesitylene and for 130 gaseous compounds in p-xylene were determined from the experimental and literature data. Abraham model correlations are determined from the experimental enthalpy of solvation data. The derived correlations describe the experimental gas-to-mesitylene and gas-to-p-xylene solvation enthalpies to within average standard deviations of 1.87 kJ mol−1 and 2.08 kJ mol−1, respectively. Enthalpies of X-H⋯π (X-O, N, and C) hydrogen bond formation of proton donor solutes (alcohols, amines, chlorinated hydrocarbons etc.) with mesitylene and p-xylene were calculated based on the Abraham solvation equation. Obtained values are in good agreement with the results determined using conventional methods
International Nuclear Information System (INIS)
Highlights: • A method for solving Fredholm integral equations using an expansion in orthogonal functions. • Speeding up the convergence by use of the analytical solution of the case with the exponential kernel. • Numerical comparisons of convergence for 7 Nataf derived kernels. - Abstract: An efficient solution of the Karhunen–Loeve (KL) integral equation is developed based on an expansion in Legendre polynomials and also an expansion in the eigenfunctions of the Markov exponential kernel for which analytic results are available. We solve the integral equation with the kernels arising from the Nataf procedure for eight different stochastic processes, viz: Markov, uniform, step, triangular, Rayleigh, exponential, log-normal and log-uniform. It may be shown that use of the Markov eigenfunctions leads to a significant improvement in computing speed over that from the Legendre polynomials. We also discuss some curious behavior associated with the convergence of the Markov eigenfunctions
Li, Zi-Cai; Yamamoto, Tetsuro; Fang, Qing
2003-02-01
The finite difference method (FDM) using the Shortley-Weller approximation can be viewed as a special kind of the finite element methods (FEMs) using the piecewise bilinear and linear functions, and involving some integration approximation. When (i.e., ) and , the superconvergence rate O(h2) of solution derivatives in discrete H1 norms by the FDM is derived for rectangular difference grids, where h is the maximal mesh length of difference grids used, and the difference grids are not confined to be quasiuniform. Comparisons are made on the analysis by the maximum principle and the FEM analysis, conversions between the FDM and the linear and bilinear FEMs are discussed, and numerical experiments are provided to support superconvergence analysis made.
Lozinova, T. A.; Lobanov, A. V.; Lander, A. V.
2015-08-01
An estimate of the content of free radicals in aqueous solutions of adenosine (Ado), adenosine-5'-diphosphate (ADP) and guanosine-5'-monophosphate (GMP) irradiated with near-UV radiation at 77 K is obtained by interpreting EPR spectra. It is established that in the presence of NaCl (0.1 M), the total number of peroxyl radicals O{2/-·} and HO{2/·} in samples of the studied compounds was 15-45% of the total quantity of produced free radicals and was affected by the conditions of exposure. The estimates are compared with the results from hydrogen peroxide (H2O2) determination in the same samples after thawing. Although the number of peroxyl radicals in the samples of adenine derivatives (A) and GMP are comparable, the formation of H2O2 is observed only in the case of A derivatives, but not in GMP. Possible reasons for these differences are discussed.
Inhibition of mild steel corrosion in hydrochloric acid solution by triazole derivatives
International Nuclear Information System (INIS)
The corrosion behaviour of mild steel in 0.1 M HCl solution without and with 5-amino-1,2,4-triazole (5-ATA), 5-amino-3-mercapto-1,2,4-triazole (5-AMT), 5-amino-3-methylthio-1,2,4-triazole (5-AMeTT) or 1-amino-3-methylthio-1,2,4-triazole (1-AMeTT) was studied as a function of the immersion time and the solution temperature. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques were used in this study. Results obtained showed that the inhibition efficiency (IE%) increases with increasing the immersion time reaching its maximum value after 1 h, IE% slightly decreased and subsisted at reasonable values at least during the studied 20 h. The adsorptive behaviour of the investigated inhibitors on the steel surface followed Langmiur-type isotherm. Increasing temperature was found to greatly enhance IE% till arriving plateau at about 80% for 5-ATA and more than 90% for the other compounds between 323 and 348 oK. The polarization and impedance measurements were in good agreement. These results indicate the suitability of the use of the investigated inhibitors in the cooling systems. The plots of lnK versus 1/T for the four studied inhibitors showed non-linear behaviour. The standard enthalpy, ΔHadso, entropy, ΔSadso and free energy changes of adsorption ΔGadso were evaluated using a proposed quadratic equation based on an inverse square dependence of the heat capacity on temperature. The calculated values of ΔGadso were negative while those for ΔHadso and ΔSadso were positive. The values of the three thermodynamic functions of adsorption for the four investigated inhibitors were decreased with increasing the solution temperature. All the above results are suggestive of chemisorption of inhibitor molecules on the steel surface
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Effect of 3.5-di-tret-butylpyrocatechol and its analogues on radical hexane transformations in deaerated solutions under impact of gamma-radiation is studied. It is shown that e.5-di-tret-butylpyrocatechol is by two-three times more effective by than its derivatives inhibits the formation of hexyle recombination products. It is shown by UV-, IR- and chromato-mass-spectrometry methods that adduct of alkyl radicals and 3.5-di-tret-butylpyrocatechenol has the structure of monoalkyl ether
International Nuclear Information System (INIS)
The biosportion of Th(IV) by the marine-derived Fungus Fusarium sp. ZZF51 was study. The Biosorption was found to be at a maximum (79.24 %), in a solution containing 50 mg Th/L, at pH 5.0, with 0.28 g dry biomass. The Temkin isotherm model and pseudo-second-order kinetic model was found to fit the data very well over the entire range of concentrations. The FTIR analysis reveals that the carboxyl, amino and hydroxyl groups on the cell wall of Fusarium sp. ZZF51 play an important role in Th(IV) biosorption process. (author)
Lead and copper removal from aqueous solutions using carbon foam derived from phenol resin.
Lee, Chang-Gu; Jeon, Jun-Woo; Hwang, Min-Jin; Ahn, Kyu-Hong; Park, Chanhyuk; Choi, Jae-Woo; Lee, Sang-Hyup
2015-07-01
Phenolic resin-based carbon foam was prepared as an adsorbent for removing heavy metals from aqueous solutions. The surface of the produced carbon foam had a well-developed open cell structure and the specific surface area according to the BET model was 458.59m(2)g(-1). Batch experiments showed that removal ratio increased in the order of copper (19.83%), zinc (34.35%), cadmium (59.82%), and lead (73.99%) in mixed solutions with the same initial concentration (50mgL(-1)). The results indicated that the Sips isotherm model was the most suitable for describing the experimental data of lead and copper. The maximum adsorption capacity of lead and copper determined to Sips model were 491mgg(-1) and 247mgg(-1). The obtained pore diffusion coefficients for lead and copper were found to be 1.02×10(-6) and 2.42×10(-7)m(2)s(-1), respectively. Post-sorption characteristics indicated that surface precipitation was the primary mechanism of lead and copper removal by the carbon foam, while the functional groups on the surface of the foam did not affect metal adsorption. PMID:25819762
Solute-Derived Thermal Stabilization of Nano-sized Grains in Melt-Spun Aluminum
Baker, A. H.; Sanders, P. G.; Lass, E. A.; Kapoor, Deepak; Kampe, S. L.
2016-08-01
Thermal stabilization of nanograined metallic microstructures (or nanostructures) can be difficult due to the large driving force for growth that arises from the inherently significant boundary area. Kinetic approaches for stabilization of the nanostructure effective at low homologous temperatures often fail at higher homologous temperatures. Alternatively, thermodynamic approaches for thermal stabilization may offer higher temperature stability. In this research, modest alloying of aluminum with solute (1 pct by mole Sc, Yb, or Sr) was examined as a means to thermodynamically stabilize a bulk nanostructure at elevated temperatures. Following 1-hour annealing treatments at 673 K (400 °C) (0.72 Tm), 773 K (500 °C) (0.83 Tm), and 873 K (600 °C) (0.94 Tm), the alloys remain nanocrystalline ( Sc. The disappearance of intermetallic phases in the Sr- and Yb-containing alloys in the X-ray diffraction spectra is observed to occur coincident with the stabilization after annealing, suggesting that precipitates dissolve and the boundaries are enriched with solute.
Structure and composition of Fe-OM co-precipitates that form in soil-derived solutions
Fritzsche, Andreas; Schröder, Christian; Wieczorek, Arkadiusz K.; Händel, Matthias; Ritschel, Thomas; Totsche, Kai U.
2015-11-01
Iron oxides represent a substantial fraction of secondary minerals and particularly affect the reactive properties of natural systems in which they formed, e.g. in soils and sediments. Yet, it is still obscure how transient conditions in the solution will affect the properties of in situ precipitated Fe oxides. Transient compositions, i.e. compositions that change with time, arise due to predominant non-equilibrium states in natural systems, e.g. between liquid and solid phases in soils. In this study, we characterize Fe-OM co-precipitates that formed in pH-neutral exfiltrates from anoxic topsoils under transient conditions. We applied soil column outflow experiments, in which Fe2+ was discharged with the effluent from anoxic soil and subsequently oxidized in the effluent due to contact with air. Our study features three novel aspects being unconsidered so far: (i) the transient composition of soil-derived solutions, (ii) that pedogenic Fe oxides instead of Fe salts serve as major source for Fe2+ in soil solution and (iii) the presence of exclusively soil-derived organic and inorganic compounds during precipitation. The experiments were carried out with two topsoil materials that differed in composition, texture and land use. Derived from Mössbauer spectroscopy, broad distributions in quadrupole splittings (0-2 mm s-1) and magnetic hyperfine fields (35-53 T) indicated the presence of low-crystalline ferrihydrite and even lower crystalline Fe phases in all Fe-OM co-precipitates. There was no unequivocal evidence for other Fe oxides, i.e. lepidocrocite and (nano)goethite. The Fe-OM co-precipitates contained inorganic (P, sulfate, silicate, Al, As) and organic compounds (proteins, polysaccharides), which were concurrently discharged from the soils. Their content in the Fe-OM co-precipitates was controlled by their respective concentration in the soil-derived solution. On a molar basis, OC and Fe were the main components in the Fe-OM co-precipitates (OC/Fe ratio = 0
Energy Technology Data Exchange (ETDEWEB)
Al-Nuri, M.A.; Abu-Eid, Maher; Zatar, N.A.; Khalaf, Shukri; Hannoun, Mohammed (An-Najah N. University, Nablus, West Bank (Israel). Chemistry Department); Khamis, Mustafa (College of Science and Technology, Abu-Dis, West Bank (Israel))
1992-04-05
A method for the spectrophotometric determination of cobalt(II) is presented, with a comparison of the binary complexes formed by cobalt (II) with di-2-pyridyl ketone nicotinoylhydrazone (DPKNH), di-2-pyridyl ketone 2-thiophenoylhydrazone (DPKTH) and di-2-pyridyl ketone benzoyl-hydrazone (DPKBH) in 50% (v/v) ethanolic solution. Cobalt(II) forms 1:2 complexes with the three reagents. Maximum absorbance is at 372 nm for Co(II)-DPKNH, at 389 nm for Co(II)-DPKTH and at 370 nm for Co(II)-DPKBH. Ranges of linearity, effects of pH and excess reagent, sensitivity, stability of the complexes and tolerance limits of ions are reported. It was concluded that the system with DPKTH is the best, followed by DPKNH and then DPKBH. The method was applied to the determination of cobalt in different alloys. (author). 17 refs.; 1 fig.; 3 tabs.
International Nuclear Information System (INIS)
A method for the spectrophotometric determination of cobalt(II) is presented, with a comparison of the binary complexes formed by cobalt (II) with di-2-pyridyl ketone nicotinoylhydrazone (DPKNH), di-2-pyridyl ketone 2-thiophenoylhydrazone (DPKTH) and di-2-pyridyl ketone benzoyl-hydrazone (DPKBH) in 50% (v/v) ethanolic solution. Cobalt(II) forms 1:2 complexes with the three reagents. Maximum absorbance is at 372 nm for Co(II)-DPKNH, at 389 nm for Co(II)-DPKTH and at 370 nm for Co(II)-DPKBH. Ranges of linearity, effects of pH and excess reagent, sensitivity, stability of the complexes and tolerance limits of ions are reported. It was concluded that the system with DPKTH is the best, followed by DPKNH and then DPKBH. The method was applied to the determination of cobalt in different alloys. (author). 17 refs.; 1 fig.; 3 tabs
A pyrazine derivative as corrosion inhibitor for steel in sulphuric acid solution
International Nuclear Information System (INIS)
The influence of diethyl pyrazine-2,3-dicarboxylate (P1) on the corrosion of steel in 0.5 M H2SO4 solution has been studied by weight loss measurements, potentiodynamic polarisation and linear polarisation resistance (Rp) and impedance spectroscopy (EIS) methods. The inhibiting action increases with the concentration of pyrazine compound to attain 82% at 10-2 M. We note good agreement between gravimetric and electrochemical methods (potentiodynamic and Rp polarisation and electrochemical impedance spectroscopy (EIS)). Polarisation measurements also show that the pyrazine acts essentially as a cathodic inhibitor. The cathodic curves indicate that the reduction of proton at the steel surface happens with an activating mechanism. The yellow deposit on the steel surface was analysed by infrared method. P1 adsorbs on the steel surface according to Langmuir adsorption model. Effect of temperature is also made in the 298-353 K range
Energy Technology Data Exchange (ETDEWEB)
Zabaleta, Jone; Mestres, Narcis; Abellan, Patricia; Gibert, Marta; Sandiumenge, Felip; Puig, Teresa; Obradors, Xavier, E-mail: jzabaleta@icmab.es, E-mail: narcis.mestres@icmab.es [Institut de Ciencia de Materials de Barcelona, ICMAB-CSIC, Campus de la UAB, Bellaterra, 08193 Barcelona, Catalunya (Spain)
2010-01-15
When one-dimensional nanostructures are epitaxially grown on a substrate a key goal is to control the nanowire's position and orientation. Nanoscratching of single crystalline (001)- LaAlO{sub 3} substrates is demonstrated to be extraordinarily effective in directing the self-assembly of Ce{sub 0.9}Gd{sub 0.1}O{sub 2-y} epitaxial nanowires grown by chemical solution deposition. The local anisotropic elastic strain field imposed by the indentation lines is responsible for the breaking of the pre-existing orientation energy degeneracy and selects the nanowires' orientation parallel to the lines to an extent that can reach 100%.
Removal of Lead (II Ions from Aqueous Solutions onto Activated Carbon Derived from Waste Biomass
Directory of Open Access Journals (Sweden)
Murat Erdem
2013-01-01
Full Text Available The removal of lead (II ions from aqueous solutions was carried out using an activated carbon prepared from a waste biomass. The effects of various parameters such as pH, contact time, initial concentration of lead (II ions, and temperature on the adsorption process were investigated. Energy Dispersive X-Ray Spectroscopy (EDS analysis after adsorption reveals the accumulation of lead (II ions onto activated carbon. The Langmuir and Freundlich isotherm models were applied to analyze equilibrium data. The maximum monolayer adsorption capacity of activated carbon was found to be 476.2 mg g−1. The kinetic data were evaluated and the pseudo-second-order equation provided the best correlation. Thermodynamic parameters suggest that the adsorption process is endothermic and spontaneous.
Solution structure of telomere binding domain of AtTRB2 derived from Arabidopsis thaliana
Energy Technology Data Exchange (ETDEWEB)
Yun, Ji-Hye [Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749 (Korea, Republic of); Lee, Won Kyung [Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749 (Korea, Republic of); Kim, Heeyoun [Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749 (Korea, Republic of); Kim, Eunhee; Cheong, Chaejoon [Magnetic Resonance Team, Korea Basic Science Institute (KBSI), Ochang, Chungbuk 363-883 (Korea, Republic of); Cho, Myeon Haeng [Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749 (Korea, Republic of); Lee, Weontae, E-mail: wlee@spin.yonsei.ac.kr [Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749 (Korea, Republic of)
2014-09-26
Highlights: • We have determined solution structure of Myb domain of AtTRB2. • The Myb domain of AtTRB2 is located in the N-terminal region. • The Myb domain of AtTRB2 binds to plant telomeric DNA without fourth helix. • Helix 2 and 3 of the Myb domain of AtTRB2 are involved in DNA recognition. • AtTRB2 is a novel protein distinguished from other known plant TBP. - Abstract: Telomere homeostasis is regulated by telomere-associated proteins, and the Myb domain is well conserved for telomere binding. AtTRB2 is a member of the SMH (Single-Myb-Histone)-like family in Arabidopsis thaliana, having an N-terminal Myb domain, which is responsible for DNA binding. The Myb domain of AtTRB2 contains three α-helices and loops for DNA binding, which is unusual given that other plant telomere-binding proteins have an additional fourth helix that is essential for DNA binding. To understand the structural role for telomeric DNA binding of AtTRB2, we determined the solution structure of the Myb domain of AtTRB2 (AtTRB2{sub 1–64}) using nuclear magnetic resonance (NMR) spectroscopy. In addition, the inter-molecular interaction between AtTRB2{sub 1–64} and telomeric DNA has been characterized by the electrophoretic mobility shift assay (EMSA) and NMR titration analyses for both plant (TTTAGGG)n and human (TTAGGG)n telomere sequences. Data revealed that Trp28, Arg29, and Val47 residues located in Helix 2 and Helix 3 are crucial for DNA binding, which are well conserved among other plant telomere binding proteins. We concluded that although AtTRB2 is devoid of the additional fourth helix in the Myb-extension domain, it is able to bind to plant telomeric repeat sequences as well as human telomeric repeat sequences.
Solution structure of telomere binding domain of AtTRB2 derived from Arabidopsis thaliana
International Nuclear Information System (INIS)
Highlights: • We have determined solution structure of Myb domain of AtTRB2. • The Myb domain of AtTRB2 is located in the N-terminal region. • The Myb domain of AtTRB2 binds to plant telomeric DNA without fourth helix. • Helix 2 and 3 of the Myb domain of AtTRB2 are involved in DNA recognition. • AtTRB2 is a novel protein distinguished from other known plant TBP. - Abstract: Telomere homeostasis is regulated by telomere-associated proteins, and the Myb domain is well conserved for telomere binding. AtTRB2 is a member of the SMH (Single-Myb-Histone)-like family in Arabidopsis thaliana, having an N-terminal Myb domain, which is responsible for DNA binding. The Myb domain of AtTRB2 contains three α-helices and loops for DNA binding, which is unusual given that other plant telomere-binding proteins have an additional fourth helix that is essential for DNA binding. To understand the structural role for telomeric DNA binding of AtTRB2, we determined the solution structure of the Myb domain of AtTRB2 (AtTRB21–64) using nuclear magnetic resonance (NMR) spectroscopy. In addition, the inter-molecular interaction between AtTRB21–64 and telomeric DNA has been characterized by the electrophoretic mobility shift assay (EMSA) and NMR titration analyses for both plant (TTTAGGG)n and human (TTAGGG)n telomere sequences. Data revealed that Trp28, Arg29, and Val47 residues located in Helix 2 and Helix 3 are crucial for DNA binding, which are well conserved among other plant telomere binding proteins. We concluded that although AtTRB2 is devoid of the additional fourth helix in the Myb-extension domain, it is able to bind to plant telomeric repeat sequences as well as human telomeric repeat sequences
Leclercq, Loïc; Nardello-Rataj, Véronique
2016-01-20
Surfactants are usually used for the preparation of emulsions. Potential drawbacks on the human body or on the environment can be observed for some of them(e.g. skin irritation, hemolysis, protein denaturation, etc.). However, it is possible to use biocompatible emulsifiers such as native cyclodextrins (CDs). The mixture of oil (paraffin oil or isopropyl myristate), water and native CDs results in the formation of Pickering emulsions. The emulsion properties were investigated by ternary phase diagrams elaboration, multiple light scattering, optical and transmission microscopies. The results prove that these Pickering emulsions were very stable against coalescence due to the dense film format the oil/water interface. The rheological behavior has shown that these emulsions remain compatible for topical applications. This kind of emulsions (biocompatibility, stability and surfactant free) has been used to obtain sustainable formulations for antifungal econazole derivatives delivery. Our results prove that these new formulations are at least as active as commercially available formulations. PMID:26616822
Institute of Scientific and Technical Information of China (English)
Li-na Zhang; Mei Zhang; Jing-hua Chen; Fan-bo Zeng
2001-01-01
Fractions of a water insoluble α-(1→3)-D-glucan (GL) extracted from Ganoderma lucidum were carboxymethylated (CM) to obtain water-soluble carboxymethylated derivatives (CM-GL) having a degree of substitution (DS) of 0.38～0.51. Weight-average molecular weight Mw and intrinsic viscosity [η] of the samples CM-GL were measured by gel permeation chromatography combined with laser light scattering (GPC-LLS) and viscometry. The CM-GL exhibits a stiffer chain in aqueous solution at 25℃ than the original glucan. The antitumor activities against Ehrlich ascites carcinoma (EAC,5 × 106) of the carboxymethylated derivatives from the α-glucan and curdlan, a β-glucan, are significantly higher than those of the original glucans. The effects of the relatively low molecular weight, expanded chains and better water-solubility of the CM-GL on the enhancement of antitumor activity could not be neglected. The chain stiffness decreased speedily with increase of temperature from 40 to 60℃ or NaOH concentration from 0.1 to 0.4 in the solution, respectively, and the change of the chain stiffness is reversible.
Neunert, Grazyna; Szwengiel, Artur; Walejko, Piotr; Witkowski, Stanislaw; Polewski, Krzysztof
2016-07-01
α-Tocopherol (Toc) is known to degrade to the tocopheroxyl radicals (Toc) by exposure to UV light irradiation. In the present study, the stability of Toc ester derivatives exposed to UV light was investigated and compared with Toc in organic solution and in phospholipid vesicles. To follow the depletion of Toc and its esters the absorbance and fluorescence methods were applied whereas degradation products were detected using LC-MS method. The irradiation with UVB light of air-equilibrated solutions of di-α-Tocopheryl malonate (DTMO), α-Tocopheryl malonate (TMO) and α-Tocopheryl succinate (TS) strongly modifies their absorption and fluorescence spectra. Upon UVB irradiation, absorption band at 279/285nm becomes less pronounced indicating the photodegradation of esters. During irradiation, the fluorescence maximum of esters at 305nm shifts to 326nm, a maximum characteristic for Toc. Photorecovery of Toc from its esters derivatives was finally confirmed by LC-MS method. Among studied esters, only α-tocopheryl nicotinate (TN) did not undergo depletion and appeared resistant to UVB radiation. Kinetic studies indicated that photoinduced transformation occurs through the first order consecutive reaction chain mechanism. The photodissociation of Toc esters in the liposomes occurred with one order of magnitude slower than in organic solvents. Using MS/MS method it was found that final stable product of irradiation was α-tocopheryl quinone (TQ), an animal and plant metabolite of Toc. PMID:27107331
Energy Technology Data Exchange (ETDEWEB)
Zhang Hong; Tang Yi; Cai Dongqing; Liu Xianan; Wang Xiangqin [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Huang Qing, E-mail: huangq@ipp.ac.cn [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Yu Zengliang, E-mail: zlyu@ipp.ac.cn [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031 (China)
2010-09-15
A novel approach to prepare activated carbon from blue-green algal bloom residue has been tried for first time and its adsorption capability to remove hexavalent chromium Cr(VI) from aqueous solution has been examined. For this algal bloom residue derived activated carbon, the physical characters regarding adsorption capability were analyzed by scanning electron microscope (SEM), energy dispersive X-ray spectroscope (EDS) and Fourier transform infrared (FTIR) spectroscopy. Batch studies showed that initial pH, absorbent dosage, and initial concentration of Cr(VI) were important parameters for Cr(VI) absorption. It was found that initial pH of 1.0 was most favorable for Cr(VI) removal. The adsorption process followed the pseudo-second-order equation and Freundlich isotherm. The maximum adsorption capacity for Cr(VI) was 155.52 mg g{sup -1} in an acidic medium, which is comparable to best result from activated carbons derived from biomass. Therefore, this work put forward a nearly perfect solution which on one hand gets rid of environment-unfriendly algae residue while on the other hand produces high-quality activated carbon that is in return advantageous to environment protection.
Removal of Congo Red and Methylene Blue from Aqueous Solutions by Vermicompost-Derived Biochars
Yang, Gang; Wu, Lin; Xian, Qiming; Shen, Fei; Wu, Jun; Zhang, Yanzong
2016-01-01
Biochars, produced by pyrolyzing vermicompost at 300, 500, and 700°C were characterized and their ability to adsorb the dyes Congo red (CR) and Methylene blue (MB) in an aqueous solution was investigated. The physical and chemical properties of biochars varied significantly based on the pyrolysis temperatures. Analysis of the data revealed that the aromaticity, polarity, specific surface area, pH, and ash content of the biochars increased gradually with the increase in pyrolysis temperature, while the cation exchange capacity, and carbon, hydrogen, nitrogen and oxygen contents decreased. The adsorption kinetics of CR and MB were described by pseudo-second-order kinetic models. Both of Langmuir and Temkin model could be employed to describe the adsorption behaviors of CR and MB by these biochars. The biochars generated at higher pyrolysis temperature displayed higher CR adsorption capacities and lower MB adsorption capacities than those compared with the biochars generated at lower pyrolysis temperatures. The biochar generated at the higher pyrolytic temperature displayed the higher ability to adsorb CR owing to its promoted aromaticity, and the cation exchange is the key factor that positively affects adsorption of MB. PMID:27144922
Inhibition of pure iron by new synthesized tripyrazole derivatives in HCl solution
International Nuclear Information System (INIS)
Inhibitory effect of some new synthesized tripyrazole compounds on corrosion of pure iron in 1 M HCl solution has been studied using weight-loss measurements and various electrochemical techniques polarization and impedance spectroscopy methods. The inhibiting action is more pronounced with N,N,N-tris[(3,5-dimethyl-1H-pyrazol-1-yl)methyl] amine (P1), and its inhibition efficiency increases with its concentration and attains the maximum value of 94% at the 2.5 x 10-4 M. The effect of temperature on the corrosion behaviour of iron was studied in the range from 298 to 353 K with and without P1 at 2.5 x 10-4 M. We note a good agreement between gravimetric and electrochemical methods potentiodynamic polarization and impedance spectroscopy (EIS). Polarization measurements show also that the compound acts mixed inhibitor. The catholic curves indicate that the reduction of proton at the pure iron surface happens within a pure activating mechanism. EIS measurements show the increase of the transfer resistance with the inhibitor concentration. The presence of the N,N,N-tris[(3,5-dimethyl-1H-pyrazol-1-yl)methyl] amine increases the inhibition efficiency and not caused a drastic change in its adsorption mechanism. The adsorption of P1 on the surface of iron in 1 M HCl obeys a Langmuir isotherm adsorption
The Use of Microwave Derived Activated Carbon for Removal of Heavy Metal in Aqueous Solution
Directory of Open Access Journals (Sweden)
Rafeah Wahi
2011-09-01
Full Text Available Palm oil processing waste which is palm oil kernel shell (POKS was converted to activated carbon (POKS AC through 7 min microwave pyrolysis at temperature 270 °C followed by chemical activation using NaOH and HCl. The adsorption study on Ni(II, Cu(II and Cr(IV was conducted to evaluate the efficiency of the prepared activated carbon to remove heavy metal. The adsorption capacity was determined as a function of adsorbate initial concentration and adsorbent dosage. Based on Langmuir isotherm, Ni(II showed highest adsorption capacity of 40.98 mg/g, followed by Cr(IV and Cu(II with adsorption capacity of 40.60 mg/g and 13.69 mg/g, respectively. Cr(IV and Cu(II showed better fitting to Freundlich isotherm model with high correlation regression indicating the applicability of heterogeneous adsorption. Ni(II show better fitting with Langmuir isotherm that indicate monolayer coverage. The use of POKS AC is not only effective for adsorption of Cr(IV, Ni(II and Cu(II in aqueous solution but also helps to overcome the over abundance of POKS waste problem.
Removal of Congo Red and Methylene Blue from Aqueous Solutions by Vermicompost-Derived Biochars.
Yang, Gang; Wu, Lin; Xian, Qiming; Shen, Fei; Wu, Jun; Zhang, Yanzong
2016-01-01
Biochars, produced by pyrolyzing vermicompost at 300, 500, and 700°C were characterized and their ability to adsorb the dyes Congo red (CR) and Methylene blue (MB) in an aqueous solution was investigated. The physical and chemical properties of biochars varied significantly based on the pyrolysis temperatures. Analysis of the data revealed that the aromaticity, polarity, specific surface area, pH, and ash content of the biochars increased gradually with the increase in pyrolysis temperature, while the cation exchange capacity, and carbon, hydrogen, nitrogen and oxygen contents decreased. The adsorption kinetics of CR and MB were described by pseudo-second-order kinetic models. Both of Langmuir and Temkin model could be employed to describe the adsorption behaviors of CR and MB by these biochars. The biochars generated at higher pyrolysis temperature displayed higher CR adsorption capacities and lower MB adsorption capacities than those compared with the biochars generated at lower pyrolysis temperatures. The biochar generated at the higher pyrolytic temperature displayed the higher ability to adsorb CR owing to its promoted aromaticity, and the cation exchange is the key factor that positively affects adsorption of MB. PMID:27144922
Solution derived p-ZnO/n-Si nanowire heterojunctions for photodetection
Pradel, Ken C.; Jevasuwan, Wipakorn; Suwardy, Joko; Bando, Yoshio; Fukata, Naoki; Wang, Zhong Lin
2016-08-01
While there is considerable interest in zinc oxide nanomaterials for optoelectronics research, one weakness of the material is the difficulty in producing p-type zinc oxide. This can be attributed to a number of factors such as acceptor instability, donor compensation during growth, and the formation of deep acceptors. Recently, it was discovered that antimony is a stable p-type dopant in hydrothermally grown ZnO nanowires, and this method has been modified to produce ultra-long nanowires and homojunction thin films. In order to broaden the applicability of this new material, it is important to investigate how it interacts with other semiconducting nanomaterials. In this work we demonstrate a solution grown p-ZnO/n-Si nanowire heterojunction. After investigating its basic materials properties, we show its applicability as an photodetector with responsivity as high as 1.02 A/W at 442 nm, an order of magnitude higher than similar nanostructures based on n-type ZnO and p-type Si.
International Nuclear Information System (INIS)
solutions of soluble silicates synthesized have been clarified in Costa Rica from diatomite in almost 50% of their initial coloration. Clarification and removal of iron oxides have been achieved in a higher order of 50% m/m expressed as Fe2 O3. Activated carbon treatment has clarified the scope of [31-57]%, but not significantly decreases the iron content. The application of NaClO to 3% m/m clarifies the scope of [28-51]%, and reduced iron by 48% m/m. The land alone has been shown that is not very effective filter to clarify, [0-14]%, but is effective for the stripping of iron by 68% m/m. Other procedures are effective in clarifying the scope of [42-51]% and reduced the amount of iron in the field of [48-66]%. The synthesis of soluble glasses is possible to clarify for conditioning with commercial purposes diverse, treatment methodologies and analytical control, simple and economical. (author)
Fiala, A.; Chibani, A.; Darchen, A.; Boulkamh, A.; Djebbar, K.
2007-10-01
Ketene dithioacetal derivatives, namely 3-[bis(methylthio)methylene] pentane-2,4-dione ( 1), 3-(1,3-dithian-2-ylidene) pentane-2,4-dione ( 2) and 3-(1,3-dithiolan-2-ylidene) pentane-2,4-dione ( 3) were synthesized and their respective capacity to inhibit copper corrosion in 3 M HNO 3 was investigated by means of weight loss, potentiodynamic polarization, scanning electron microscopy (SEM) and energy dispersive X-ray fluorescence (XRF). The obtained results indicate that the addition of these compounds significantly decreases the corrosion rate. Potentiodynamic polarization studies clearly showed that the inhibition efficiency increases with increasing concentration of the investigated compounds at a fixed temperature, but decreases with increasing temperature. These results on the whole showed that the studied substances are good cathodic inhibitors for copper corrosion in nitric acid medium. SEM and energy dispersive X-ray (EDAX) examination of the copper surface revealed that these compounds prevented copper from corrosion by adsorption on its surface to form a protective film, which acts as a barrier to aggressive agents. The presence of these organic compounds adsorbed on the electrode surface was confirmed by XRF investigations.
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Highlights: ► Partition coefficients octanol/buffer of new drug-like spiro-derivatives were determined. ► Thermodynamic functions of transfer were calculated. ► The correlations partition coefficients and molecular descriptors are discussed. -- Abstract: Temperature dependences of partition coefficient for 11 drug-like spiro-derivatives of 1,3-thiazine in the system aqueous phosphate buffer/organic phase (hexane, octanol) have been determined over the temperature range (293.15 to 315.15) K by the isothermal saturation method. The effects of aliphatic chain substituent structure and introduction of oxygen, chlorine, bromine and fluorine atoms on the partitioning processes of the substances studied were examined. It has been established that among the substances investigated halogen derivatives possess the lowest partition coefficients in buffer/hexane system and the highest ones in buffer/octanol system. Regularities between the partition coefficients and the descriptors reflecting the capability of the solutes to undergo specific and nonspecific interactions with solvent molecules were revealed. The thermodynamic functions describing the partitioning process were calculated. It was found that differences in the partition coefficients depend on the enthalpies of transfer
The Role of Liver in Determining Serum Colon-Derived Uremic Solutes.
Directory of Open Access Journals (Sweden)
Cheng-Jui Lin
Full Text Available Evidence has shown that indoxyl sulfate (IS and p-cresyl sulfate (PCS may be alternative predictors of clinical outcomes in chronic kidney disease (CKD. Both toxins are derived from the gastrointestinal tract and metabolised in the liver. However, it is unclear whether the liver affects the production of IS and PCS. Here, we explore the association between IS and PCS levels in liver cirrhosis and a CKD-based cohort (N = 115. Liver and kidney function was assessed and classified by a Child-Pugh score (child A-C and a modified version of the Modification of Diet in Renal Disease (MDRD equation (Stages 1-4, respectively. An animal model was also used to confirm the two toxin levels in a case of liver fibrosis. In patients with early liver cirrhosis (child A, IS and PCS were significantly associated with CKD stages. In contrast, serum IS and PCS did not significantly change in advanced liver cirrhosis (child C. A stepwise multiple linear regression analysis also showed that T-PCS was significantly associated with stages of liver cirrhosis after adjusting for other confounding factors (B = -2.29, p = 0.012. Moreover, the serum and urine levels of T-PCS and T-IS were significantly lower in rats with liver failure than in those without (p<0.01, p<0.05 and p<0.01, p<0.05, respectively. These results indicated that in addition to the kidneys, the liver was an essential and independent organ in determining serum IS and PCS levels. The production rate of IS and PCS was lower in patients with advanced liver cirrhosis.
International Nuclear Information System (INIS)
Water pollution caused by ammonia nitrogen has attracted a great attention as its toxicity affects both the environment and human health. The objective of this paper was to investigate the adsorption behavior of NH4+-N from aqueous solution by activated carbons prepared from rice husk. The physico-chemical properties of the activated carbon were characterized by Brunauer-Emmett-Teller (BET) test, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). It was found that the NH4+-N adsorption on the rice husk derived carbons was dependent on adsorbent dosage and solution pH. The adsorption kinetics and isotherms of NH4+-N by rice husk carbon were also investigated, and good correlation coefficients were obtained for the pseudo-second order kinetic equation. Dubinin-Radushkevitch (D-R) adsorption isotherm model could better describe the adsorption behavior of NH4+-N on the rice husk carbon. Calculated by D-R model, the adsorption course of NH4+-N on the rice husk carbon was favored chemical ion-exchange mechanism. Moreover, the activated carbon adsorbed NH4+-N was highly fertilizer conservation especially for the nitrogen element. It was proposed that the amount of removed NH4+-N from aqueous solutions would increase evidently treated by rice husk carbon if combined with biological method. -- Highlights: ► The dosage of rice husk carbon and pH affected the removal of NH4+-N from aqueous solution. ► D-R model could better describe the adsorption behavior of NH4+-N on the rice husk carbon. ► The removing of NH4+-N would be risen by rice husk carbon if combined with biological method.
Improved light emission utilizing polyfluorene derivatives by thermal printing and solution process
Kasama, Daisuke; Takata, Ryotaro; Kajii, Hirotake; Inoue, Jun; Yoshino, Katsumi; Ohmori, Yutaka
2009-08-01
The emission properties of polymer light-emitting diode (PLEDs), using blue emissive poly(9,9-dioctylfluorene) (PFO) and yellow-green emissive poly[9,9-dioctylfluorenyl-2,7-diyl)-co-1, 4-benzo-{2,1'-3}- thiadiazole)] (F8BT) fabricated by the spin-coating method, the toluene vapor method and the thermal printing method, were investigated. poly(2,7-(9,9-din-octylfluorene)-alt-(1,4-phenylene-( (4-sec-butylphenyl)imino)-1,4-phenylene)) (TFB) is useful for buffer layer and a dopant when we use the spin-coating method. When we use TFB as interlayer of PLED, TFB acts as exciton-blocking layer, thus prevents luminescence quenching. When we use TFB with 2-(4-biphenylyl)-5-phenyl-1,3,4-oxadiazole (PBD) as dopants of PFO, better current efficiency was achieved, compared to PFO only device. This result derives from these materials working as hole and electron transporting molecules. The blue and yellow-green PLEDs fabricated by the spincoating method showed maximum efficiencies of approximately 1.1 and 1cd/A, respectively. The device with bis[1-(9,9-dimethyl-9H-fluoren-2-yl)-isoquinoline](acetylacetonate)iridium(III) (Ir(fliq)2acac) doped in PFO showed red-emission and a maximum efficiency of approximately 1cd/A. Current efficiencies of PLEDs with the β phase of PFO fabricated by the thermal printing method and the toluene vapor method were found to have better emission efficiency than that with the amorphous phase of PFO by the spin-coating method. The EL spectra of PLEDs using PFO and PFO:F8BT fabricated by the thermal printing method were polarized. The transient characteristics of PLEDs using β phase of PFO were better than amorphous phase of that. It is expected to improve the characteristics of PLEDs by the optimization of the thermal printing method. We demonstrated improved light emission of PLEDs with the high-quality β phase by the thermal printing method.
Jiang, B.; Jiang, S. L.; Liu, X.; Ma, A. L.; Zheng, Y. G.
2015-12-01
This study investigates the performance of three triazole derivatives with different molecular structures as corrosion inhibitors for the copper-nickel alloy CuNi 90/10 in 3.5 wt.% NaCl solution. Inhibition behavior was systematically determined through electrochemical measurements, scanning electron microscopy, energy-dispersive spectroscopy, and Fourier transform infrared spectroscopy. In addition, adsorption behavior and the inhibition mechanism were investigated via quantum chemical calculation and molecular dynamic simulation. Experimental results indicate that the three inhibitors with triazole rings and heteroatoms exhibited excellent corrosion inhibition capabilities on the copper-nickel alloy surface through physisorption and chemisorption. In particular, 3-amino-5-mercapto-1,2,4-triazole showed the best inhibition capability according to the concentration ranges considered in the experiments. The results of quantum chemical calculation agreed with the experimental findings.
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The effect of changes in the chemical structure of organic sulfur compounds on their reactivity towards an ortho-positronium (o-Ps) atom was investigated by positron annihilation lifetime spectroscopy in dimethylsulfoxide solutions. S-bridge containing molecules with very similar structural frameworks were selected as model systems, such as, diphenyl sulfide, sulfoxide and sulfone, and their derivatives. The effect of the type of the S-bridge on the reactivity increased in the order of S 2 in all groups of the compounds with similar substituents on their phenyl groups. The same trend was observed for the calculated excess positive charge on the sulfur atoms and the LUMO energies of the molecules too. As it was expected, electron-withdrawing substituents on the aromatic rings increased both the reactivity and the negative values of the LUMO energy of the molecules (COOH 2) whereas those with electron-donating character (CH3O) showed the opposite effect
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Deana Wahyuningrum
2008-03-01
Full Text Available Oleic imidazoline is one of the nitrogen containing heterocyclic compounds that has been widely used as commercial corrosion inhibitor, especially in minimizing the carbon dioxide induced corrosion process in oilfield mining. In this present work, some imidazoline derivative compounds have been synthesized utilizing both conventional and microwave assisted organic synthesis (MAOS methods, in order to determine their corrosion inhibition properties on carbon steel surface. The MAOS method is more effective in synthesizing these compounds than the conventional method regarding to the higher chemical yields of products (91% to 94% and the shorter reaction times (7 to 10 minutes. The characterization of corrosion inhibition activities of the synthesized products towards carbon steel in 1% NaCl solution was determined by the Tafel plot method. The corrosion inhibition activities of compound 1b ((Z-2-(2-(heptadec-8-enyl-4,5-dihydroimidazol-1-ylethanamine, 2b ((Z-2-(2-(heptadec-8-enyl-4,5-dihydroimidazol-1-ylethanol and 3b (2-(2-heptadecyl-4,5-dihydroimidazol-1-ylethanamine at 8 ppm concentration in 1% NaCl solution are, respectively, 32.18%, 39.59% and 12.73%. The heptadec-8-enyl and hydroxyethyl substituents at C(2 and N(1 position of imidazoline ring, respectively, gave the most effective corrosion inhibition activity towards carbon steel compared to the presence of other substituents. The increase in concentrations of compound 1b, 2b and 3b in 1% NaCl solution tends to improve their corrosion inhibition activities. Based on the analysis of the free Gibbs adsorption energy (DG0ads values of compound 1b, 2b and 3b (-32.97, -34.34 and -31.27 kJ/mol, respectively, these compounds have the potential to interact with carbon steel through semi-physiosorption or semi-chemisorption.
Tehrani, Mahnaz Saghanejhad; Zare-Dorabei, Rouholah
2016-05-01
MIL-68(Al) as a metal-organic framework (MOF) was synthesized and characterized by different techniques such as SEM, BET, FTIR, and XRD analysis. This material was then applied for simulations removal of malachite green (MG) and methylene blue (MB) dyes from aqueous solutions using second order derivative spectrophotometric method (SODS) which was applied to resolve the overlap between the spectra of these dyes. The dependency of dyes removal efficiency in binary solutions was examined and optimized toward various parameters including initial dye concentration, pH of the solution, adsorbent dosage and ultrasonic contact time using central composite design (CCD) under response surface methodology (RSM) approach. The optimized experimental conditions were set as pH 7.78, contact time 5 min, initial MB concentration 22 mg L- 1, initial MG concentration 12 mg L- 1 and adsorbent dosage 0.0055 g. The equilibrium data was fitted to isotherm models such as Langmuir, Freundlich and Tempkin and the results revealed the suitability of the Langmuir model. The maximum adsorption capacity of 666.67 and 153.85 mg g- 1 was obtained for MB and MG removal respectively. Kinetics data fitting to pseudo-first order, pseudo-second order and Elovich models confirmed the applicability of pseudo-second order kinetic model for description of the mechanism and adsorption rate. Dye-loaded MIL-68(Al) can be easily regenerated using methanol and applied for three frequent sorption/desorption cycles with high performance. The impact of ionic strength on removal percentage of both dyes in binary mixture was studied by using NaCl and KCl soluble salts at different concentrations. According to our findings, only small dosage of the proposed MOF is considerably capable to remove large amounts of dyes at room temperature and in very short time that is a big advantage of MIL-68(Al) as a promising adsorbent for adsorptive removal processes.
Tehrani, Mahnaz Saghanejhad; Zare-Dorabei, Rouholah
2016-05-01
MIL-68(Al) as a metal-organic framework (MOF) was synthesized and characterized by different techniques such as SEM, BET, FTIR, and XRD analysis. This material was then applied for simulations removal of malachite green (MG) and methylene blue (MB) dyes from aqueous solutions using second order derivative spectrophotometric method (SODS) which was applied to resolve the overlap between the spectra of these dyes. The dependency of dyes removal efficiency in binary solutions was examined and optimized toward various parameters including initial dye concentration, pH of the solution, adsorbent dosage and ultrasonic contact time using central composite design (CCD) under response surface methodology (RSM) approach. The optimized experimental conditions were set as pH7.78, contact time 5min, initial MB concentration 22mgL(-1), initial MG concentration 12mgL(-1) and adsorbent dosage 0.0055g. The equilibrium data was fitted to isotherm models such as Langmuir, Freundlich and Tempkin and the results revealed the suitability of the Langmuir model. The maximum adsorption capacity of 666.67 and 153.85mgg(-1) was obtained for MB and MG removal respectively. Kinetics data fitting to pseudo-first order, pseudo-second order and Elovich models confirmed the applicability of pseudo-second order kinetic model for description of the mechanism and adsorption rate. Dye-loaded MIL-68(Al) can be easily regenerated using methanol and applied for three frequent sorption/desorption cycles with high performance. The impact of ionic strength on removal percentage of both dyes in binary mixture was studied by using NaCl and KCl soluble salts at different concentrations. According to our findings, only small dosage of the proposed MOF is considerably capable to remove large amounts of dyes at room temperature and in very short time that is a big advantage of MIL-68(Al) as a promising adsorbent for adsorptive removal processes. PMID:26890205
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The second derivative spectra (2nd DS) of U(IV), U(VI) and Pu(III) in nitric acid solution in investigated and compared with each species' absorption spectra (AS). The influences of HNO3, H+ and other impurities on 2nd DS and AS of these species are discussed. Wide and intensive absorption band can be declined by derivation. On the other hand, weak but sharp absorption band can be amplified by derivation. U(IV) causes serious interference on absorption spectra of U(VI) and Pu(III) if the concentration of U(IV) is higher than the concentrations of U(VI) and Pu(III). But in 2nd DS, the characteristic peaks of U(VI) and Pu(III) can be easily discerned and U(IV) slightly affects their determinations. The height of negative peak at 415 nm can be used to determine U(VI) concentration. Either the negative peak at 584 nm or the positive peak at 665 nm can be used to determine Pu(III) concentration depending on concrete situation. The determination of U(IV) is scarcely affected by Pu(III) and U(VI), and its concentration can be determined via several peaks' height. 2.5-3.0 mol/l HNO3 is suitable for the determination with the analysis deviation below 5.0%. The low-limits of determination for Pu(III), U(IV) and U(VI) are 0.5, 0.1 and 1 mmol/l, respectively
Directory of Open Access Journals (Sweden)
Jintao Song
2015-01-01
Full Text Available The foundation boundaries of numerical simulation models of hydraulic structures dominated by a vertical load are investigated. The method used is based on the stress formula for fundamental solutions to semi-infinite space body elastic mechanics under a vertical concentrated force. The limit method is introduced into the original formula, which is then partitioned and analyzed according to the direction of the depth extension of the foundation. The point load will be changed to a linear load with a length of 2a. Inverse proportion function assumptions are proposed at parameter a and depth l of the calculation points to solve the singularity questions of elastic stress in a semi-infinite space near the ground. Compared with the original formula, changing the point load to a linear load with a length of 2a is more reasonable. Finally, the boundary depth criterion of a hydraulic numerical simulation model is derived and applied to determine the depth boundary formula for gravity dam numerical simulations.
International Nuclear Information System (INIS)
After briefly reviewing the present understanding of the nucleation process of YBCO films, a new approach is presented to enhance the stability of c-axis nucleation in epitaxial chemical solution deposited YBCO thin films derived from TFA precursors. We show that with silver addition to the TFA precursor c-axis nucleation can be reached in a wide range of temperature thus keeping high percolating Jc. We argue that silver reduces supersaturation and makes more stable the c-axis nuclei without modifying Tc. Additional advantages of silver addition are an enhanced surface smootheness and a reduced porosity of the YBCO films. The second reported topic relates to the discovery of an adverse relationship between percolating Jc and YBCO films mesostrain, as determined through X-ray diffraction line broadening. We show that mesostrain is enhanced in processes leading to inefficient strain healing at grain boundaries, for instance annealing times too short or growth temperatures too low. It is suggested that the strained regions at the low angle grain boundaries lead to a weak link behavior which can be microscopically understood on the basis of pair formation prevention, as proposed by the bond contraction pairing model.
Obradors, X.; Martínez-Julián, F.; Zalamova, K.; Vlad, V. R.; Pomar, A.; Palau, A.; Llordés, A.; Chen, H.; Coll, M.; Ricart, S.; Mestres, N.; Granados, X.; Puig, T.; Rikel, M.
2012-11-01
After briefly reviewing the present understanding of the nucleation process of YBCO films, a new approach is presented to enhance the stability of c-axis nucleation in epitaxial chemical solution deposited YBCO thin films derived from TFA precursors. We show that with silver addition to the TFA precursor c-axis nucleation can be reached in a wide range of temperature thus keeping high percolating Jc. We argue that silver reduces supersaturation and makes more stable the c-axis nuclei without modifying Tc. Additional advantages of silver addition are an enhanced surface smootheness and a reduced porosity of the YBCO films. The second reported topic relates to the discovery of an adverse relationship between percolating Jc and YBCO films mesostrain, as determined through X-ray diffraction line broadening. We show that mesostrain is enhanced in processes leading to inefficient strain healing at grain boundaries, for instance annealing times too short or growth temperatures too low. It is suggested that the strained regions at the low angle grain boundaries lead to a weak link behavior which can be microscopically understood on the basis of pair formation prevention, as proposed by the bond contraction pairing model.
Energy Technology Data Exchange (ETDEWEB)
Salahinejad, E., E-mail: salahinejad@kntu.ac.ir [Faculty of Materials Science and Engineering, K.N. Toosi University of Technology, Tehran (Iran, Islamic Republic of); School of Materials Science and Engineering, Helmerich Advanced Technology Research Center, Oklahoma State University, Tulsa, OK (United States); Department of Materials Science and Engineering, School of Engineering, Shiraz University, Shiraz (Iran, Islamic Republic of); Hadianfard, M.J. [Department of Materials Science and Engineering, School of Engineering, Shiraz University, Shiraz (Iran, Islamic Republic of); Vashaee, D. [School of Electrical and Computer Engineering, Helmerich Advanced Technology Research Center, Oklahoma State University, Tulsa, OK (United States); Tayebi, L., E-mail: lobat.tayebi@okstate.edu [School of Materials Science and Engineering, Helmerich Advanced Technology Research Center, Oklahoma State University, Tulsa, OK (United States); School of Chemical Engineering, Oklahoma State University, Stillwater, OK (United States)
2014-03-15
Highlights: • By increasing pH, the thermal stability of the amorphous particles increases. • pH did not affect the size and morphology of the synthesized nanoparticles. • The thermal behavior was explained by the adsorption of hydroxide ions. -- Abstract: This paper concerns with the effect of pH on the structure and crystallization behavior of particulate sol–gel derived zirconium titanate. According to differential scanning calorimetry, it was found that the thermal stability of the synthesized amorphous particles was enhanced by increasing the precursor solution pH value from 4 to 10, as confirmed by X-ray diffraction. Transmission electron microscopy studies on the xerogel and crystallized nanoparticles showed that the pH value does not fairly affect their size and morphology; thus, these structural features cannot have a meaningful contribution to the detected crystallization difference. The realized thermal behavior was explained based on a mechanism relating to the adsorption of hydroxide ions (OH{sup −}) existing in the medium to metallic hydroxide precipitates synthesized during the sol–gel process. In this regard, it was speculated that the more the pH value is increased, as reasonably accompanied by the more hydroxide adsorption, the more the crystallization event is inhibited.
Little, Mark P; Gola, Anna; Tzoulaki, Ioanna; Vandoolaeghe, Wendy
2009-01-01
The paper of Little et al. (PloS Comput Biol 2009 5(10) e1000539) outlined a system of reaction-diffusion equations that were used to describe induction of atherosclerotic disease. These were solved by considering an equilibrium solution and small perturbations around this equilibrium. Here we consider slight variant sets of assumptions that could be used to derive equilibrium solutions. In general they do not imply any change in the numerical results relating to monocyte chemo-attractant pro...
Institute of Scientific and Technical Information of China (English)
曹建莉
2007-01-01
Finite-dimensional integrable Hamiltonian systems, obtained through the nonlinearization of the 3×3 spectral problems associated with the Manakov and the derivative Manakov equations, are investigated. A generating function method is used to give a simple and effective way to prove the involutivity of integrals. Finite-parameter solutions of the Manakov and the derivative Manakov equations are calculated based on the commutative systems of ordinary differential equations with these integrals as Hamiltonians.
International Nuclear Information System (INIS)
Highlights: • Urea and its alkyl derivatives in aqueous NaCl solutions were studied. • The density and the speed of sound were measured for presented systems. • The strongest impact of NaCl on obtained quantities is noticed for apparent molar compression. • Bigger hydrophobic character of the solute results in bigger changes of calculated quantities with concentration. • The geometry of the solute is a crucial condition for hydrophobic hydration to happen. - Abstract: The present work was undertaken to study volumetric and acoustic properties for diluted solutions of tetramethylurea in pure water and for urea, n-propylurea, n-butylurea and tetramethylurea in 0.5 or 1 mol · dm−3 aqueous solutions of sodium chloride. This paper presents measured values of densities and sound velocities at T = (288.15, 298.15 and 308.15) K. From these data the apparent molar volumes, VΦ, adiabatic compressibilities, κS, and apparent molar adiabatic compressions, KS,Φ, were obtained. The values of apparent molar volumes for infinite dilution and limited apparent adiabatic compressions were calculated from extrapolation of the concentration dependence. Further, the corresponding transfer data as well as hydration number of urea and its derivatives in the studied systems were estimated. The obtained parameters are discussed in terms of various solute-solvent and solute-cosolute interactions
Chatterjee, Kausik
2016-06-01
The objective of this paper is the extension and application of a newly-developed Green's function Monte Carlo (GFMC) algorithm to the estimation of the derivative of the solution of the one-dimensional (1D) Helmholtz equation subject to Neumann and mixed boundary conditions problems. The traditional GFMC approach for the solution of partial differential equations subject to these boundary conditions involves "reflecting boundaries" resulting in relatively large computational times. My work, inspired by the work of K.K. Sabelfeld is philosophically different in that there is no requirement for reflection at these boundaries. The underlying feature of this algorithm is the elimination of the use of reflecting boundaries through the use of novel Green's functions that mimic the boundary conditions of the problem of interest. My past work has involved the application of this algorithm to the estimation of the solution of the 1D Laplace equation, the Helmholtz equation and the modified Helmholtz equation. In this work, this algorithm has been adapted to the estimation of the derivative of the solution which is a very important development. In the traditional approach involving reflection, to estimate the derivative at a certain number of points, one has to a priori estimate the solution at a larger number of points. In the case of a one-dimensional problem for instance, to obtain the derivative of the solution at a point, one has to obtain the solution at two points, one on each side of the point of interest. These points have to be close enough so that the validity of the first-order approximation for the derivative operator is justified and at the same time, the actual difference between the solutions at these two points has to be at least an order of magnitude higher than the statistical error in the estimation of the solution, thus requiring a significantly larger number of random-walks than that required for the estimation of the solution. In this new approach
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The Einstein-Cartan theory of gravitation allows for avoiding singularities. This idea is supported by giving exact solution of cosmological equations which are extensions of the Friedmannian cosmology. Various singularity-free models of dust and radiative universes are constructed. Two general relations are given which allow for a transition from dust-filled to radiation-filled universes with the same value of the scale factor. These relations are characteristic of the Einstein-Cartan theory, and cannot be brought over into general relativity. It is shown how exact solutions of the Einstein-Cartan theory can be derived from known solutions of general rela tivity. This procedure which may be applied to material spheres, is simple enough to generate a large set of useful solutions. Two examples are given. (author)
Energy Technology Data Exchange (ETDEWEB)
Aviv, Hagit [Department of Chemistry, Bar-Ilan University (Israel); Institute for Nanotechnology and Advanced Materials, Bar-Ilan University (Israel); Tischler, Yaakov R., E-mail: yrt@biu.ac.il [Department of Chemistry, Bar-Ilan University (Israel); Institute for Nanotechnology and Advanced Materials, Bar-Ilan University (Israel)
2015-02-15
Here we present the synthesis and optical characterization of a new amphiphilic cyanine dye, 1,1′-dioctadecane-3,3′-di(4-sulfobutyl)-5,5′,6,6′-tetrachloro -benzimidazolocarbo-cyanine (C18S4). C18S4 is a derivative of the heavily studied J-aggregating cyanine dye TDBC that was designed specifically for creating stable amphiphilic monolayers when spread at an air–water interface. Unlike TDBC, which readily J-aggregates in water, we show that C18S4 introduced into water tends to produce micelles with monomeric spectral properties and only exhibits strong J-aggregation after an emulsification procedure and a week of dye reorganization. When deposited on a Langmuir Blodgett (LB) trough, C18S4 forms a stable monolayer with a repeatable isotherm. Layers transferred via LB deposition to a functionalized glass substrate show pronounced J-aggregation, depending on the surface transfer pressure. Layers transferred at 35 mN/m present an intense narrow absorption spectrum peaked at λ=589 nm with FWHM=523 cm{sup −1} (18 nm). The accompanying fluorescence shows a narrow spectrum with FWHM=332 cm{sup −1} (11.5 nm) and a Stokes shift less than 1 nm. The ability to create J-aggregates of C18S4 via LB deposition provides control over the J-aggregation process of TDBC-like molecules and can ultimately lead to tuning the J-aggregate coupling for specific experiments and applications. - Highlights: • C18S4 is an amphiphilic J-aggregating cyanine dye. • C18S4 J-aggregates in aqueous solution. • C18S4 forms a stable isotherm when spread at the air–water interface. • C18S4 J-aggregates at an air–water interface upon compression. • Langmuir–Blodgett J-aggregated films have narrow absorption and emission spectra.
Khaled, K. F.
2010-09-01
The effects of thiourea derivatives, namely N-methyl thiourea (MTU), N-propyl thiourea (PTU) and N-allyl thiourea (ATU) on the corrosion behaviour of iron in 1.0 M solution of HNO 3 have been investigated in relation to the concentration of thiourea derivatives. The experimental data obtained using the techniques of weight loss, Tafel polarization and electrochemical impedance spectroscopy, EIS. The results showed that these compounds revealed a good corrosion inhibition, (ATU) being the most efficient and (MTU) the least. Computational studies have been used to find the most stable adsorption sites for thiourea derivatives. This information help to gain further insight about corrosion system, such as the most likely point of attack for corrosion on iron (1 1 0), the most stable site for thiourea derivatives adsorption and the binding energy of the adsorbed layer. The efficiency order of the inhibitors obtained by experimental results was verified by theoretical analysis.
Energy Technology Data Exchange (ETDEWEB)
Park, Hong-Gyu; Lee, Yun-Gun; Jang, Sang Bok; Lee, Ju Hwan; Jeong, Hae-Chang; Seo, Dae-Shik, E-mail: dsseo@yonsei.ac.kr [Information Display Device Laboratory, Department of Electrical and Electronic Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749 (Korea, Republic of); Oh, Byeong-Yun [ZeSHTech Co., Ltd., Business Incubator, Gwangju Institute of Science and Technology, 123, Cheomdangwagi-ro, Buk-gu, Gwangju 500-712 (Korea, Republic of)
2015-11-15
Hafnium yttrium gallium oxide (HfYGaO) films were applied to liquid crystal displays (LCDs) as liquid crystal (LC) alignment layers, replacing conventional polyimide (PI) layers. The HfYGaO alignment layers were prepared by fabricating solution-processed HfYGaO films, annealing them, and treating them with ion-beam (IB) irradiation. The authors studied the effects of annealing temperature and IB irradiation of the solution-derived HfYGaO films on the orientation of LC molecules. The LC molecules on the solution-derived HfYGaO films were homogeneously and uniformly aligned by IB irradiation, irrespective of the annealing temperature. Atomic force microscopy analyses revealed that the surface reformation of the HfYGaO films induced by IB irradiation strengthened the van der Waals force between the LC molecules and the HfYGaO films, leading to uniform LC alignment. Enhanced electro-optical characteristics were observed in the twisted-nematic (TN) LCDs based on IB-irradiated HfYGaO films compared with those of TN-LCDs based on PI layers, demonstrating the high application potential of the proposed solution-derived HfYGaO films as LC alignment layers.
Gwenzi, Willis; Musarurwa, Tinashe; Nyamugafata, Phillip; Chaukura, Nhamo; Chaparadza, Allen; Mbera, Sharron
2014-01-01
The Zn(2+) and Ni(2+) adsorption capacities of six biosorbents derived from water hyacinth (Eichhornia crassipes) (WH) and sawdust (SD) were investigated, with activated carbon as the control. The biosorbents were raw biomass (WH, SD), charred WH (BWH) and SD and sulphonated bio-chars of WH and SD. The effect of the initial solution pH and Zn(2+) and Ni(2+) concentrations on adsorption capacity was studied, and adsorption isotherms for Zn(2+) and Ni(2+) evaluated. The initial solution pH significantly influenced adsorption (p water and wastewater treatment. PMID:25353949
Soklakov, Andrei N.
2013-01-01
Quantitative Structuring is a rigorous framework for the design of financial products. We show how it incorporates traditional investment ideas while supporting a more accurate expression of clients' views on the market. We briefly touch upon adjacent topics regarding the safety of financial derivatives and the role of pricing models in product design.
International Nuclear Information System (INIS)
Azo-dyes derivative (HL) sorbent was synthesized according to the literature to be used in the adsorption and preconcentration of Th(IV) ions from aqueous solution and it was exposed to immobilization, and new solid support material was obtained. For this purpose, azo-dyes derivative (HL) was chemically bonded to silica gel surface immobilized 3-chloropropyl trimethoxysilane, then analyzed by FTIR, BET, SEM and elemental analysis. The influence of the solution pH, initial Th(IV) concentration, amount of sorbent, contact time, temperature and foreign ion effect was investigated. The maximum Th(IV) uptake capacity was found to be 24.85 ± 0.2 mg/g. (author)
International Nuclear Information System (INIS)
Schiff base hydrazone derivative (HL) sorbent was synthesized according to the literature to be used in the adsorption and preconcentration of U(VI) ions from aqueous solution and it was exposed to immobilization, and new solid support material was obtained. For this purpose, Schiff base hydrazone derivative (HL) was chemically bonded to silica gel surface immobilized 3-aminopropyl trimethoxysilane, then analyzed by Fourier transform infrared, Brunauer-Emmett-Teller, scanning electron microscopy and elemental analysis. The influence of the solution pH, amount of sorbent, contact time, temperature, foreign ion effect and initial U(VI) concentration was investigated. The maximum U(VI) uptake capacity was found to be 8.46 mg/g. (author)
Takahashi, Daisuke A.
2016-04-01
The matrix-generalized Bogoliubov-de Gennes systems have recently been considered by the present author [Phys. Rev. B 93, 024512 (2016)], and time-dependent and self-consistent multisoliton solutions have been constructed based on the ansatz method. In this paper, restricting the problem to the static case, we exhaustively determine the self-consistent solutions using the inverse scattering theory. Solving the gap equation, we rigorously prove that the self-consistent potential must be reflectionless. As a supplementary topic, we elucidate the relation between the stationary self-consistent potentials and the soliton solutions in the matrix nonlinear Schrödinger equation. Asymptotic formulae of multisoliton solutions for sufficiently isolated solitons are also presented.
Takahashi, Daisuke A
2015-01-01
The matrix-generalized Bogoliubov-de Gennes systems are recently considered by the present author [arXiv:1509.04242], and the time-dependent and self-consistent multi-soliton solutions are constructed based on the ansatz method. In this paper, restricting the problem to the static case, we exhaustively determine the self-consistent solutions using the inverse scattering theory. Solving the gap equation, we rigorously prove that the self-consistent potential must be reflectionless. As a supplementary topic, we elucidate the relation between the stationary self-consistent potentials and the soliton solutions in the matrix nonlinear Schr\\"odinger equation. The asymptotic formulae of multi-soliton solutions for sufficiently isolated solitons are also presented.
Mahmood, A.; Parveen, S.; Ara, A.; Khan, N. A.
2009-08-01
The velocity field and the associated shear stress corresponding to the torsional oscillatory flow of a generalized Maxwell fluid, between two infinite coaxial circular cylinders, are determined by means of the Laplace and Hankel transforms. Initially, the fluid and cylinders are at rest and after some time both cylinders suddenly begin to oscillate around their common axis with different angular frequencies of their velocities. The solutions that have been obtained are presented under integral and series forms in terms of generalized G and R functions. Moreover, these solutions satisfy the governing differential equation and all imposed initial and boundary conditions. The respective solutions for the motion between the cylinders, when one of them is at rest, can be obtained from our general solutions. Furthermore, the corresponding solutions for the similar flow of ordinary Maxwell fluid are also obtained as limiting cases of our general solutions. At the end, flows corresponding to the ordinary Maxwell and generalized Maxwell fluids are shown and compared graphically by plotting velocity profiles at different values of time and some important results are remarked.
Ghosh, Uttam; Sengupta, Srijan; Sarkar, Susmita; Das, Shantanu
2015-01-01
There is no unified method to solve the fractional differential equation. The type of derivative here used in this paper is of Jumarie formulation, for the several differential equations studied. Here we develop an algorithm to solve the linear fractional differential equation composed via Jumarie fractional derivative in terms of Mittag-Leffler function; and show its conjugation with ordinary calculus. In these fractional differential equations the one parameter Mittag-Leffler function plays...
Al Janabi, Mazin A. M.
2006-01-01
Purpose – Since, the early 1990s, emerging markets have started to play an important role in the trading of derivatives products. Despite the fact that these markets are characterized in general as illiquid, segmented, politically unstable, with lack of regulations and historical financial databases, they do have some advantages for markets' participants. This paper aims to discuss some of the main obstacles to the inception of successful derivative products in emerging economies and to provi...
Energy Technology Data Exchange (ETDEWEB)
Jeong, Hae-Chang; Park, Hong-Gyu; Lee, Ju Hwan; Seo, Dae-Shik, E-mail: dsseo@yonsei.ac.kr [Information Display Device Laboratory, Department of Electrical and Electronic Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749 (Korea, Republic of); Oh, Byeong-Yun [ZeSHTech Co., Ltd., Business Incubator, Gwangju Institute of Science and Technology, 123, Cheomdangwagi-ro, Buk-gu, Gwangju 500-712 (Korea, Republic of)
2015-11-15
The authors demonstrate a high performance electrically controlled birefringence (ECB) mode with solution-derived La{sub 2}O{sub 3} films at various molar concentrations. Uniform and homogeneous liquid crystal (LC) alignment was spontaneously achieved on the La{sub 2}O{sub 3} films for lanthanum concentrations at ratios greater than and equal to 0.2. A preferred orientation of LC molecules appeared along the filling direction, and the LC alignment was maintained via van der Waals force by nanocrystals of the La{sub 2}O{sub 3} films. The LC alignment mechanism was confirmed by x-ray photoelectron spectroscopy and high-resolution transmission electron microscopy analysis. Superior electro-optical characteristics of the ECB cells constructed with solution-derived La{sub 2}O{sub 3} films were observed, which suggests that the proposed solution-derived La{sub 2}O{sub 3} films have strong potential for use in the production of advanced LC displays.
International Nuclear Information System (INIS)
Enthalpies of solution of methanol and 2-methyl-2-propanol (tert-butanol) in pyridine and its methyl derivatives were investigated in the range of mole fractions of alcohol x≤0.02 at temperature 298.15 K by a titration calorimeter. Dissolution of methanol is an exothermic process, with heat effects very close to those for water reported in part I of this study. The negative enthalpy of solution increases in the following order: pyridine < 3-methylpyridine < 4-methylpyridine < 2-methylpyridine < 2,6-dimethylpyridine < 2,4,6-trimethylpyridine. Positive enthalpies of solution of 2-methyl-2-propanol increase as follows: 2-methylpyridine < 2,4,6-trimethylpyridine < 4-methylpyridine < 2,6-dimethylpyridine < 3-methylpyridine < pyridine. The propensity of pyridine derivatives to hydrogen bonding is enhanced by the ortho effect. Methyl groups are probably too small to prevent the nitrogen atom in the pyridine ring from hydrogen bonding. However, spacious hydrocarbon group in 2-methyl-2-propanol molecule makes the bonding difficult for 2,6-dimethylpyridine and 2,4,6-trimethylpyridine, thus the number of O-H···N bonds is smaller than that in the solutions of methanol or water. The two latter seem to be very close to each other
McDuffee, Ryan
2016-01-01
Recent observations of gravitational waves by the Laser Interferometer Gravitational-Wave Observatory (LIGO) has confirmed one of the last outstanding predictions in general relativity and in the process opened up a new frontier in astronomy and astrophysics. Additionally the observation of gravitational waves has also given us the data needed to deduce the physical properties of space time. Bredberg et al have shown in their 2011 paper titled From Navier-Stokes to Einstein, that for every solution of the incompressible Navier-Stokes equation in p + 1 dimensions, there is a uniquely associated dual" solution of the vacuum Einstein equations in p + 2 dimensions. The author shows that the physical properties of space time can be deduced using the recent measurements from the Laser Interferometer Gravitational-Wave Observatory and solutions from the incompressible Navier-Stokes equation.
Sawale, R. T.; Deosarkar, S. D.; Kalyankar, T. M.
2015-07-01
Density ( ρ), viscosity ( η) and refractive index ( n D) of an antiemetic drug metoclopramide (4-amino-5-chloro- N-(2-(diethylamino)ethyl)-2-methoxybenzamide hydrochloride) solutions containing amino acids (glycine, D-alanine, L-cystine and L-histidine) were measured in the concentration range 0.01-0.17 mol/dm3 at 303.15 K. The apparent molar volume (φv) of this drug in aqueous amino acid solutions was calculated from the density data and fitted to the Massons relation, and the partial molar volume φ{v/0} of the drug was determined graphically. The partial molar volumes of transfer (Δtrφ{v/0}) of drug at infinite dilution from pure water to aqueous amino acid solutions were calculated and interpreted in terms of different interactions between the drug and amino acids.
Energy Technology Data Exchange (ETDEWEB)
Claesson, J.; Probert, T. [Lund Univ. (Sweden). Dept. of Building Physics and Mathematical Physics
1996-01-01
The temperature field in rock due to a large rectangular grid of heat releasing canisters containing nuclear waste is studied. The solution is by superposition divided into different parts. There is a global temperature field due to the large rectangular canister area, while a local field accounts for the remaining heat source problem. The global field is reduced to a single integral. The local field is also solved analytically using solutions for a finite line heat source and for an infinite grid of point sources. The local solution is reduced to three parts, each of which depends on two spatial coordinates only. The temperatures at the envelope of a canister are given by a single thermal resistance, which is given by an explicit formula. The results are illustrated by a few numerical examples dealing with the KBS-3 concept for storage of nuclear waste. 8 refs.
Exact solutions for the flow of non-Newtonian fluid with fractional derivative in an annular pipe
Institute of Scientific and Technical Information of China (English)
TONG; Dengke; WANG; Ruihe; YANG; Heshan
2005-01-01
This paper deals with some unsteady unidirectional transient flows of Oldroyd-B fluid in an annular pipe. The fractional calculus approach in the constitutive relationship model Oldroyd-B fluid is introduced and a generalized Jeffreys model with the fractional calculus has been built. Exact solutions of some unsteady flows of Oldroyd-B fluid in an annular pipe are obtained by using Hankel transform and Laplace transform for fractional calculus. The following four problems have been studied: (1) Poiseuille flow due to a constant pressure gradient; (2) axial Couette flow in an annulus; (3) axial Couette flow in an annulus due to a longitudinal constant shear; (4) Poiseuille flow due to a constant pressure gradient and a longitudinal constant shear. The well-known solutions for Navier-Stokes fluid, as well as those corresponding to a Maxwell fluid and a second grade one, appear as limited cases of our solutions.
International Nuclear Information System (INIS)
The temperature field in rock due to a large rectangular grid of heat releasing canisters containing nuclear waste is studied. The solution is by superposition divided into different parts. There is a global temperature field due to the large rectangular canister area, while a local field accounts for the remaining heat source problem. The global field is reduced to a single integral. The local field is also solved analytically using solutions for a finite line heat source and for an infinite grid of point sources. The local solution is reduced to three parts, each of which depends on two spatial coordinates only. The temperatures at the envelope of a canister are given by a single thermal resistance, which is given by an explicit formula. The results are illustrated by a few numerical examples dealing with the KBS-3 concept for storage of nuclear waste. 8 refs
DEFF Research Database (Denmark)
Bunk, Oliver; Nielsen, Martin Meedom; Sølling, Theis Ivan;
2003-01-01
A surface X-ray diffraction study is presented showing that highly ordered and uniaxially aligned hexa(3,7-dimethyl-octanyl)hexa-peri-hexabenzocoronene (HBC-C8,2) films can be fabricated by crystallization from solution onto friction-transferred poly(tetrafluoroethylene) (PTFE) layers. Three crys...
Directory of Open Access Journals (Sweden)
T. D. Nekipelova
1999-01-01
Full Text Available Reactions of transient species photogenerated from 6-R-2,2,4-trimethyl-1,2-dihydroquinolines (TMDQ are very sensitive to medium variation. In anhydrous organic solvents, aminyl radicals were generated. They decay in the reaction of dimerization with the second-order rate constant decreasing in a row heptane>benzene>2-propanol. When passing from organic solvents to water, methanol, and water-alcohol solutions, the kinetics and the direction of the reaction crucially change. As a result of the photolysis, the product of the addition of a solvent to the double bond of heterocycle, 4-hydroxy- or 4-methoxy-6-R-2,2,4- tetramethyl-1,2,3,4-tetrahydroquinoline is formed in water and methanol, respectively. The transformation is a complex reaction, and the formation of excited transient species is followed by a sequence of first-order and pseudo-first-order reactions. Unlike the photolysis in anhydrous organic solvents, the reaction in water and methanol does not involve aminyl radicals. In aqueous solutions, the first-order rate constants for the decay of transient species are higher in acidic and neutral solutions. At the pH close to pKa of the transient species, it drops, indicating that the neutral form is less reactive. The same product is formed over the whole range of pH. For the anionic surfactant (SDS in acidic and alkaline solutions, the apparent rate constant in the micellar solutions is lower than that in the aqueous (negative micellar catalysis. At the medium pH, a positive micellar catalysis is observed, and the rate constant of the decay depends linearly on the concentration of TMDQ in the micelles, indicative of the direct reaction between TMDQ and the cationic transient species.
Rahbar, Alireza; Farjadfard, Sima; Leili, Mostafa; Kafaei, Raheleh; Haghshenas, Vajiheh; Ramavandi, Bahman
2016-09-01
In this experimental data article, a novel biomaterial was provided from Malva sylvestris and characterized its properties using various instrumental techniques. The operating parameters consisted of pH and adsorbent dose on Hg(2+) adsorption from aqueous solution using M. sylvestris powder (MSP) were compared with charcoal tablet powder (CTP), a medicinal drug. The data acquired showed that M. sylvestris is a viable and very promising alternative adsorbent for Hg(2+) removal from aqueous solutions. The experimental data suggest that the MSP is a potential adsorbent to use in medicine for treatment of poisoning with heavy metals; however, the application in animal models is a necessary step before the eventual application of MSP in situations involving humans. PMID:27294181
Reactions between cerium(IV) and methyl-6-x-derivatives of aniline in perchloric acid solutions
International Nuclear Information System (INIS)
The oxidation of 2,6-dimethyl-, 2-isopropyl-6-methyl, 2-chloro-6-methyl-and 2-methyl-6-nitro aniline with cerium(IV) in perchloric acid solutions has been examined. It has been found that the concentration of hydrogen ions and the basicity of nitrogen atom in the amine group decide about the resultant intermediate products. Some of these products can be practically prepared using cerium(IV) as an oxidizing agent. (author). 16 refs, 1 tab
International Nuclear Information System (INIS)
Spectrophotometric study of the derivative of 1-(2-methoxyphenyl)-3,3-diphenylpropyne reveals that in diethyl ether it exists as contact ion pairs (CIP's). In THF the solvent separated ion pairs (SSIP's) are predominant in the accordance with spectrophotometric and 13C NMR data. Regioselectivities of reactions of the lithium derivative under study with ethyl halides in diethyl ether, THF and hexamethyphosphoramide, with benzyl chloride in two first solvents, and with methanol in THF were investigated. The protonation with methanol was shown to proceed exclusively at the allenic center (C-1) while the ethylation and especially the benzylation were shown to proceed predominantly at the propargylic center (C-3). Regioselectivities of the ethylation at the propargylic center of both the SSIP's in THF and the CIP's in diethyl ether were found to grow with the increase of the hardness of the ethylating agent
International Nuclear Information System (INIS)
Dipyridamole, 2,6-bis(diethanolamino)-4,8-dipiperidino-pyrimido-pyrimidine, (DIP) has been widely used as a drug. The biological activity of this drug depends largely upon the nature of the substituents. In the present work, data on hydrogen-1 and carbon-13 NMR of DIP and some of its derivates are analysed in order to improve the knowledge of physico-chemical properties of these compounds. The methodology is presented. Results are reported and discussed
Energy Technology Data Exchange (ETDEWEB)
Bentiss, Fouad; Lebrini, Mounim; Lagrenee, Michel [Laboratoire de Cristallochimie et Physicochimie du Solide, CNRS UMR 8012, ENSCL, BP. 108, F-59652 Villeneuve d' Ascq Cedex (France); Herve, Vezin [Laboratoire de Chimie Organique et Macromoleculaire, CNRS UMR 8009, USTL Bat C3, F-59655 Villeneuve d' Ascq Cedex (France)
2004-07-01
In this work, a new class of thiadiazole derivatives, namely 3,5-bis(2-thienyl)-1,3,4-thiadiazole (2-TTH) and 3,5-bis(3-thienyl)-1,3,4-thiadiazole (3-TTH), have been studied as possible corrosion inhibitors for mild steel in molar hydrochloric acid (1M HCl). Polarisation curves and AC impedance methods have been used. These studies have shown that the thiadiazole derivatives were very good inhibitors for mild steel in 1M HCl. Comparison of results showed that 3-TTH was the best inhibitor. The potential of zero charge (PZC) of mild steel was studied by ac impedance method, and the mechanism of adsorption has been predicted. X-ray photoelectron spectroscopy surface analysis with thiadiazole derivatives shows that it chemisorbed at the mild steel/HCl interface. The adsorption of these inhibitors followed Langmuir's adsorption isotherm. The electronic properties of 2-TTH and 3-TTH, obtained using the AM1 semi-empirical quantum chemical approach, were correlated with their experimental efficiencies using the linear resistance model (LR). (authors)
Energy Technology Data Exchange (ETDEWEB)
Pourjavid, Mohammad Reza [Islamic Azad University, Tehran (Iran, Islamic Republic of). Dept. of Medicinal Chemistry. Nuclear Science and Technology Research Institute; Rezaee, Mohammad; Hosseini, Majid Haji [Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of); Razavi, Taherehsadat, E-mail: pourjavid@gmail.com [Research Institute of Petroleum Industry, Tehran (Iran, Islamic Republic of). Instrumental Analysis Dept.
2012-07-01
A furan-triazole derivative has been explored as an ionophore for preparation of a highly selective Pr(III) membrane sensor. The proposed sensor exhibits a Nernstian response for Pr(III) activity over a wide concentration range with a detection limit of 5.2 x 10{sup -8}M. Its response is independent of pH of the solution in the range 3.0-8.8 and offers the advantages of fast response time. To investigate the analytical applicability of the sensor, it was applied successfully as an indicator electrode in potentiometric titration of Pr(III) solution and also in the direct and indirect determination of trace Pr(III) ions in some samples. (author)
International Nuclear Information System (INIS)
La2Zr2O7/NiW buffer layers as very promising buffer layers for coated conductors were fabricated by chemical solution deposition using cheap precursors, La-acetate and Zr-(IV) n-propoxide (70% w/w in n-propanol). The effects on the orientation and microstructure of La2Zr2O7 buffer layers, including seed layer, thickness and solution concentration, were investigated. The results showed that insertion of a seed layer could obviously improve the crystallization and orientation, and decrease of single layer thickness could also obviously improve the in-plane orientation. The results of all metalorganic depositions derived YBCO/CeO2/La2Zr2O7/NiW showed that the prepared La2Zr2O7 buffer layers were suitable for coated conductors using all metalorganic depositions
International Nuclear Information System (INIS)
We investigate optimal control problems for linear distributed systems which are not solved with respect to the time derivative and whose homogeneous part admits a degenerate strongly continuous solution semigroup. To this end, we first obtain theorems on the existence of a unique strong solution of the Cauchy problem. This enables us to formulate sufficient conditions for the solubility of the optimal control problems under consideration. In contrast to earlier papers on a similar topic, we substantially weaken the conditions on the quality functional with respect to the state function. The abstract results thus obtained are illustrated by an example of an optimal control problem for the linearized system of Navier-Stokes equations.
International Nuclear Information System (INIS)
A furan-triazole derivative has been explored as an ionophore for preparation of a highly selective Pr(III) membrane sensor. The proposed sensor exhibits a Nernstian response for Pr(III) activity over a wide concentration range with a detection limit of 5.2 x 10-8M. Its response is independent of pH of the solution in the range 3.0-8.8 and offers the advantages of fast response time. To investigate the analytical applicability of the sensor, it was applied successfully as an indicator electrode in potentiometric titration of Pr(III) solution and also in the direct and indirect determination of trace Pr(III) ions in some samples. (author)
International Nuclear Information System (INIS)
A hydrophobically-modified polyacrylamide and two partially hydrolyzed derivatives containing hydrophobic and carboxylic groups were prepared by micellar polymerization and post hydrolysis. The molecular weight, second virial coefficient and radius of gyration were determined by static light scattering (SLS). Dynamic light scattering (DLS) and small-angle X-ray scattering (SAXS) were employed to determine the aggregate formation and type of chain packing in the semidilute regime, respectively. The behavior of solutions in dilute and semidilute regimes was also studied by viscometry and rheology. The hydrophobically-modified polyacrylamide showed a tendency to form aggregates due to the hydrophobic groups, but not enough to increase apparent viscosity. The partially hydrolyzed derivatives did not show the same aggregate-forming tendency. Rather, they exhibited anisotropic behavior, due to the charge density introduced into the polymer chain, which led to a more elongated macromolecular conformation and higher viscosity. (author)
Energy Technology Data Exchange (ETDEWEB)
Maia, Ana M.S.; Vidal, Rosangela R.L.; Balaban, Rosangela C., E-mail: balaban@supercabo.com.b [Universidade Federal do Rio Grande do Norte (LAPET/DQ/UFRN), Natal, RN (Brazil). Dept. de Quimica. Lab. de Pesquisa em Petroleo; Villetti, Marcos A. [Universidade Federal de Santa Maria (DF/UFSM), RS (Brazil). Dept. de Fisica; Borsali, Redouane [Universite Bordeaux 1, Pessac Cedex (France)
2011-07-01
A hydrophobically-modified polyacrylamide and two partially hydrolyzed derivatives containing hydrophobic and carboxylic groups were prepared by micellar polymerization and post hydrolysis. The molecular weight, second virial coefficient and radius of gyration were determined by static light scattering (SLS). Dynamic light scattering (DLS) and small-angle X-ray scattering (SAXS) were employed to determine the aggregate formation and type of chain packing in the semidilute regime, respectively. The behavior of solutions in dilute and semidilute regimes was also studied by viscometry and rheology. The hydrophobically-modified polyacrylamide showed a tendency to form aggregates due to the hydrophobic groups, but not enough to increase apparent viscosity. The partially hydrolyzed derivatives did not show the same aggregate-forming tendency. Rather, they exhibited anisotropic behavior, due to the charge density introduced into the polymer chain, which led to a more elongated macromolecular conformation and higher viscosity. (author)
International Nuclear Information System (INIS)
Highlights: • First application of a DNA derived fluorescent bio-dot for metal sensing. • Bio-dot was conveniently obtained via a mild thermal hydro-thermal synthesis. • Bio-dot was directly used for fluorescent sensing without further modification. • Bio-dot showed good fluorescent sensing property for Hg(II) and Ag(I). • Formation of T–Hg–T and C–Ag–C structures played key roles in sensing. - Abstract: Inspired by the high affinity between heavy metal ions and bio-molecules as well as the low toxicity of carbon-based quantum dots, we demonstrated the first application of a DNA derived carbonaceous quantum dots, namely bio-dots, in metal ion sensing. The present DNA-derived bio-dots contain graphitic carbon layers with 0.242 nm lattice fringes, exhibit excellent fluorescence property and can be obtained via a facile hydrothermal preparation procedure. Hg(II) and Ag(I) are prone to be captured by the bio-dots due to the existence of residual thymine (T) and cytosine (C) groups, resulting in a quenched fluorescence while other heavy metal ions would cause negligible changes on the fluorescent signals of the bio-dots. The bio-dots could be used as highly selective toxic-free biosensors, with two detecting linear ranges of 0–0.5 μM and 0.5–6 μM for Hg(II) and one linear range of 0–10 μM for Ag(I). The detection limits (at a signal-to-noise ratio of 3) were estimated to be 48 nM for Hg(II) and 0.31 μM for Ag(I), respectively. The detection of Hg(II) and Ag(I) could also be realized in the real water sample analyses, with satisfying recoveries ranging from 87% to 100%
Energy Technology Data Exchange (ETDEWEB)
Song, Ting [Laboratory of Environmental Science and Technology, Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Zhu, Xuefeng, E-mail: zhuxf@ms.xjb.ac.cn [Laboratory of Environmental Science and Technology, Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011 (China); Zhou, Shenghai [Laboratory of Environmental Science and Technology, Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011 (China); Yang, Guang [Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education and International Center for Dielectric Research, Xi’an Jiaotong University, Xi’an 710049 (China); Gan, Wei [Laboratory of Environmental Science and Technology, Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011 (China); Yuan, Qunhui, E-mail: yuanqh@ms.xjb.ac.cn [Laboratory of Environmental Science and Technology, Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011 (China)
2015-08-30
Highlights: • First application of a DNA derived fluorescent bio-dot for metal sensing. • Bio-dot was conveniently obtained via a mild thermal hydro-thermal synthesis. • Bio-dot was directly used for fluorescent sensing without further modification. • Bio-dot showed good fluorescent sensing property for Hg(II) and Ag(I). • Formation of T–Hg–T and C–Ag–C structures played key roles in sensing. - Abstract: Inspired by the high affinity between heavy metal ions and bio-molecules as well as the low toxicity of carbon-based quantum dots, we demonstrated the first application of a DNA derived carbonaceous quantum dots, namely bio-dots, in metal ion sensing. The present DNA-derived bio-dots contain graphitic carbon layers with 0.242 nm lattice fringes, exhibit excellent fluorescence property and can be obtained via a facile hydrothermal preparation procedure. Hg(II) and Ag(I) are prone to be captured by the bio-dots due to the existence of residual thymine (T) and cytosine (C) groups, resulting in a quenched fluorescence while other heavy metal ions would cause negligible changes on the fluorescent signals of the bio-dots. The bio-dots could be used as highly selective toxic-free biosensors, with two detecting linear ranges of 0–0.5 μM and 0.5–6 μM for Hg(II) and one linear range of 0–10 μM for Ag(I). The detection limits (at a signal-to-noise ratio of 3) were estimated to be 48 nM for Hg(II) and 0.31 μM for Ag(I), respectively. The detection of Hg(II) and Ag(I) could also be realized in the real water sample analyses, with satisfying recoveries ranging from 87% to 100%.
Ford Versypt, Ashlee N.; Arendt, Paul D.; Pack, Daniel W.; Braatz, Richard D.
2015-01-01
A mathematical reaction-diffusion model is defined to describe the gradual decomposition of polymer microspheres composed of poly(D,L-lactic-co-glycolic acid) (PLGA) that are used for pharmaceutical drug delivery over extended periods of time. The partial differential equation (PDE) model treats simultaneous first-order generation due to chemical reaction and diffusion of reaction products in spherical geometry to capture the microsphere-size-dependent effects of autocatalysis on PLGA erosion that occurs when the microspheres are exposed to aqueous media such as biological fluids. The model is solved analytically for the concentration of the autocatalytic carboxylic acid end groups of the polymer chains that comprise the microspheres as a function of radial position and time. The analytical solution for the reaction and transport of the autocatalytic chemical species is useful for predicting the conditions under which drug release from PLGA microspheres transitions from diffusion-controlled to erosion-controlled release, for understanding the dynamic coupling between the PLGA degradation and erosion mechanisms, and for designing drug release particles. The model is the first to provide an analytical prediction for the dynamics and spatial heterogeneities of PLGA degradation and erosion within a spherical particle. The analytical solution is applicable to other spherical systems with simultaneous diffusive transport and first-order generation by reaction. PMID:26284787
Directory of Open Access Journals (Sweden)
Ashlee N Ford Versypt
Full Text Available A mathematical reaction-diffusion model is defined to describe the gradual decomposition of polymer microspheres composed of poly(D,L-lactic-co-glycolic acid (PLGA that are used for pharmaceutical drug delivery over extended periods of time. The partial differential equation (PDE model treats simultaneous first-order generation due to chemical reaction and diffusion of reaction products in spherical geometry to capture the microsphere-size-dependent effects of autocatalysis on PLGA erosion that occurs when the microspheres are exposed to aqueous media such as biological fluids. The model is solved analytically for the concentration of the autocatalytic carboxylic acid end groups of the polymer chains that comprise the microspheres as a function of radial position and time. The analytical solution for the reaction and transport of the autocatalytic chemical species is useful for predicting the conditions under which drug release from PLGA microspheres transitions from diffusion-controlled to erosion-controlled release, for understanding the dynamic coupling between the PLGA degradation and erosion mechanisms, and for designing drug release particles. The model is the first to provide an analytical prediction for the dynamics and spatial heterogeneities of PLGA degradation and erosion within a spherical particle. The analytical solution is applicable to other spherical systems with simultaneous diffusive transport and first-order generation by reaction.
International Nuclear Information System (INIS)
We report a versatile optical sensor by incorporating the indicator dye 4-phenyl-2,6-bis(2,3,5,6-tetrahydrobenzo[b][1,4,7]trioxononin-9-yl)pyrylium perchlorate into a sol-gel layer. The proposed optical sensor that is stable, fast and highly selective to Hg2+ ions shows a significant absorbance signal change on exposure to an aqueous solution containing mercury(II) ion. The sensing film is able to determine mercury(II) ion in aqueous solution with a high selectivity over a wide dynamic range between 1.52 x 10-9 and 1.70 x 10-2 M, at pH 5, and a lower detection limit of 1.11 x 10-9 M. Validation of the assay method revealed excellent performance characteristics for Hg2+ ions over a wide variety of other metal ions, including good selectivity, long-term response stability and high reproducibility. Applications, for the direct determination of mercury(II) in real samples, gave the results with good correlation with the data obtained by using cold vapor atomic absorption spectrometry.
Diaferia, Carlo; Mercurio, Flavia Anna; Giannini, Cinzia; Sibillano, Teresa; Morelli, Giancarlo; Leone, Marilisa; Accardo, Antonella
2016-01-01
Water soluble fibers of PEGylated tetra-phenylalanine (F4), chemically modified at the N-terminus with the DOTA chelating agent, have been proposed as innovative contrast agent (CA) in Magnetic Resonance Imaging (MRI) upon complexation of the gadolinium ion. An in-depth structural characterization of PEGylated F4-fibers, in presence (DOTA-L6-F4) and in absence of DOTA (L6-F4), is reported in solution and at the solid state, by a multiplicity of techniques including CD, FTIR, NMR, DLS, WAXS and SAXS. This study aims to better understand how the aggregation process influences the performance of nanostructures as MRI CAs. Critical aggregation concentrations for L6-F4 (43 μM) and DOTA-L6-F4 (75 μM) indicate that self-aggregation process occurs in the same concentration range, independently of the presence of the CA. The driving force for the aggregation is the π-stacking between the side chains of the aromatic framework. CD, FTIR and WAXS measurements indicate an antiparallel β-sheet organization of the monomers in the resulting fibers. Moreover, WAXS and FTIR experiments point out that in solution the nanomaterials retain the same morphology and monomer organizations of the solid state, although the addition of the DOTA chelating agent affects the size and the degree of order of the fibers. PMID:27220817
Prenesti, Enrico; Berto, Silvia; Daniele, Pier Giuseppe
2003-01-01
In this study we considered π-methyl- L-histidine (π-methis) and τ-methyl- L-histidine (τ-methis) as ligands for copper(II) ion, in order to clarify, by means of ultraviolet (UV) spectroscopy in aqueous solution ( T=25 °C, I=0.1 M), some aspects of the co-ordination mode with respect to other ligands of a previous study in which copper(II) complexes of L-histidine, N-acetyl- L-histidine, histamine, L-histidine methyl ester or carnosine were investigated. Particularly, UV spectra (300-400 nm) were recorded on solutions at various pH values, containing each binary system Cu-L; afterwards, an UV absorption spectrum for single complexes was calculated, taking into account the chemical model previously assessed, in order to fulfil a correct spectrum-structure correlation. The problem related to the eventual superimposition of the CT shoulder (≈330 nm) to copper(II) of OH - and imidazole pyridine nitrogen groups were now solved by means of a comparison of the UV spectra of dimer species formed by both π-methis or τ-methis. Finally, copper(II) complex formation with 2,2'-bipyridine was taken into account to compare the behaviour of pyridine (from 2,2'-bipyridine) and pyridine imidazole nitrogens (from π-methis or τ-methis) with respect to the UV charge transfer process to copper(II) ion.
El-Faham, Ayman; Osman, Sameh M; Al-Lohedan, Hamad A; El-Mahdy, Gamal A
2016-01-01
The corrosion inhibition performance of 2-hydrazino-4,6-dimethoxy-1,3,5-tirazine (DMeHT), 2,4-dihydrazino-6-methoxy-1,3,5-triaizine (DHMeT), and 2,4,6-tridydrazino-1,3,5-triaizne (TH₃) on steel corrosion in acidic media was examined using electrochemical techniques. The results showed 2,4-Ddihydrazino-6-methoxy-1,3,5-triaizine (DHMeT) gave the best corrosion protection performance among the other hydrazino derivatives even at a low concentration of 25 ppm (95%). The number of hydrazino groups play an important role in the corrosion inhibition, where the two hydrazine groups increased the electrostatic interactions between the protonated tested compounds, the negatively charged steel surface resulted from the adsorption of the chloride anions, and the presence of the methoxy group made the compound more reliable for formation of film protection on the surface of steel through the lone pair of oxygen atoms. Electrochemical Impedance Spectroscopy (EIS) measurements suggested that the corrosion process of steel in presence of the hydrazino-s-triazine derivatives (TH₃, DMeHT and DHMeT) were being controlled by the charge transfer reaction. Polarization curves indicated that the examined TH₃, DMeHT and DHMeT behaved as mixed type inhibitors. PMID:27258241
Room temperature electrical properties of solution derived p-type Cu2ZnSnS4 thin films
Gupta, Goutam Kumar; Dixit, Ambesh
2016-05-01
Electrical properties of solution processed Cu2ZnSnS4 (CZTS) compound semiconductor thin film structures on molybdenum (Mo) coated glass substrates are investigated using Mott-Schottky and Impedance spectroscopy measurements at room temperature. These measurements are carried out in sodium sulfate (Na2SO4) electrolytic medium at pH ~ 9.5. The inversion/depletion/accumulation regions are clearly observed in CZTS semiconductor -Na2SO4 electrolyte interface and measured flat band potential is ~ -0.27 V for CZTS thin film electrode. The positive slope of the depletion region confirms the intrinsic p-type characteristics of CZTS thinfilms with ~ 2.5× 1019 holes/m3. The high frequency impedance measurements showed ~ 30 Ohm electrolyte resistance for the investigated configuration.
Jung, Kyung-Won; Jeong, Tae-Un; Kang, Ho-Jeong; Ahn, Kyu-Hong
2016-07-01
In this work, granular biochar, Laminaria japonica-derived biochar (LB)-calcium alginate beads (LB-CAB), was successfully prepared by dropping a mixture of powder biochar and alginate solution into a calcium chloride solution for phosphate adsorption. Among different marine macroalgae derived biochars, LB exhibited the best performance, showing a phosphate removal rate of 97.02%, which was attributed to its high Ca/P and Mg/P ratios. With increasing pyrolysis temperature up to 600°C, the physicochemical properties of LB became suitable for adsorbing phosphate. Experimental results of kinetics and equilibrium isotherms at different temperatures (10-30°C) showed that the phosphate adsorption process is endothermic and is mainly controlled by external mass transfer and the intraparticle diffusion rate. The maximum adsorption capacity was found to be 157.7mgg(-1) at 30°C, as fitted by the Langmuir-Freundlich model, which is higher than capacities of other powder form of biochars. PMID:27010340
Stolaroff, J. K.; Lowry, G. V.; Keith, D. W.
2003-12-01
To mitigate global climate change, deep reductions in CO2 emissions are required in the coming decades. Carbon sequestration will play a crucial role in this reduction. Early adoption of carbon sequestration in low-cost niche markets will help develop the technology and experience required for large-scale deployment. One such niche may be the use of alkali metals from industrial waste streams to form carbonate minerals, a safe and stable means of sequestering carbon. In this research, the potential of using two industrial waste streams---concrete and steel slag---for sequestering carbon is assessed. The scheme is outlined as follows: Ca and Mg are leached with water from a finely ground bed of steel slag or concrete. The resulting solution is sprayed through air, capturing CO2 and forming solid carbonates, and collected. The feasibility of this scheme is explored with a combination of experiments, theoretical calculations, cost accounting, and literature review. The dissolution kinetics of steel slag and concrete as a function of particle size and pH is examined. In stirred batch reactors, the majority of Ca which dissolved did so within the first hour, yielding between 50 and 250 (mg; Ca)/(g; slag) and between 10 and 30 (mg; Ca)/(g; concrete). The kinetics of dissolution are thus taken to be sufficiently fast to support the type of scheme described above. As proof-of-concept, further experiments were performed where water was dripped slowly through a stagnant column of slag or concrete and collected at the bottom. Leachate Ca concentrations in the range of 15 mM were achieved --- sufficient to support the scheme. Using basic physical principles and numerical methods, the quantity of CO2 captured by falling droplets is estimated. Proportion of water loss and required pumping energy is similarly estimated. The results indicate that sprays are capable of capturing CO2 from the air and that the water and energy requirements are tractable. An example system for
Characterization of rapid thermally processed LiMn2O4 thin films derived from solution deposition
Institute of Scientific and Technical Information of China (English)
MA Ming-you; XIAO Zhuo-bing; Li Xin-hai; WU Xian-ming; HE Ze-qiang; CHEN Shang
2006-01-01
Cathode material LiMn2O4 thin films were prepared through solution deposition followed by rapid thermal annealing. The phase identification and surface morphology were studied by X-ray diffraction and scanning electron microscopy. Electrical and electrochemical properties were examined by four-probe method, cyclic voltammetry and galvanostatic charge-discharge experiments. The results show that the film prepared by this method is homogeneous, dense and crack-free. As the annealing temperature and annealing time increase, the electronic resistivity decreases, while the capacity of the films increases generally. For the thin films annealed at different temperatures for 2 min, the thin film annealed at 800 ℃ has the best cycling behavior with the capacity loss of 0.021% per cycle. While for the thin films annealed at 750 ℃ for different times, the film annealed for 4 min possesses the best cycling performance with a capacity loss of 0.025% per cycle. For the lithium diffusion coefficient in LiMn2O4 thin film, its magnitude order is 10-11 cm2·s-1.
Hadjittofi, Loukia; Prodromou, Melpomeni; Pashalidis, Ioannis
2014-05-01
The adsorption efficiency of activated biochar prepared from cactus fibres regarding the removal of Cu(II) from aqueous solutions has been investigated as a function of various physicochemical parameters (e.g. pH, initial metal concentration, ionic strength, temperature and contact time). Activation of the biochar took place using nitric acid oxidation and characterisation was performed by SEM analysis, FTIR spectroscopy, N2 adsorption and acid-base titrations. The results show that laminar structures constitute the material and carboxylic moieties are the predominant binding sites. The experimental data were analyzed by the Langmuir, Freundlich and Dubinin-Radushkevich adsorption models and the monolayer adsorption capacity was found to be 3.5 mol kg(-1). The effect of ionic strength and temperature on the adsorption efficiency indicates that at low pH outer-sphere and at near neutral pH inner-sphere complexes are the predominant surface species and the kinetic data obtained were fitted very well by the Lagergren rate expression. PMID:24718356
Zhang, Feng; Wang, Xin; Yin, Daixia; Peng, Bo; Tan, Changyin; Liu, Yunguo; Tan, Xiaofei; Wu, Shixue
2015-04-15
This study investigated the efficiency and mechanisms of Cd removal by biochar pyrolyzed from water hyacinth (BC) at 250-550 °C. BC450 out-performed the other BCs at varying Cd concentrations and can remove nearly 100% Cd from aqueous solution within 1 h at initial Cd ≤ 50 mg l(-1). The process of Cd sorption by BC450 followed the pseudo-second order kinetics with the equilibrium being achieved after 24 h with initial Cd ranging from 100 to 500 mg l(-1). The maximum Cd sorption capacity of BC450 was estimated to be 70.3 mg g(-1) based on Langmuir model, which is prominent among a range of low-cost sorbents. Based on the balance analysis between cations released and Cd sorbed onto BC450 in combination with SEM-EDX and XPS data, ion-exchange followed by surface complexation is proposed as the dominant mechanism responsible for Cd immobilization by BC450. In parallel, XRD analysis also suggested the formation of insoluble Cd minerals (CdCO3, Cd3P2, Cd3(PO4)2 and K4CdCl6) from either (co)-precipitation or ion exchange. Results from this study highlighted that the conversion of water hyacinth into biochar is a promising method to achieve effective Cd immobilization and improved management of this highly problematic invasive species. PMID:25660498
Energy Technology Data Exchange (ETDEWEB)
Gallego-Gomez, Francisco; Villalvilla, Jose M.; Quintana, Jose A.; Diaz-Garcia, Maria A. [Instituto Universitario de Materiales de Alicante and Dpto. Fisica Aplicada, Universidad de Alicante, 03080 Alicante (Spain); Garcia-Frutos, Eva M.; Gutierrez-Puebla, Enrique; Monge, Angeles; Gomez-Lor, Berta [Instituto de Ciencia de Materiales de Madrid, CSIC, C/Sor Juana Ines de la Cruz 3, 28049 Madrid (Spain)
2011-02-22
A new carbazole-related small molecule exhibiting self-assembly into ordered nanostructures in solution-processed cast films has been synthesized and its charge-photogeneration and -transport properties have been investigated. Large photoconductivity was measured in the amorphous state while an enormous improvement in the photoconduction properties was observed when the molecules spontaneously organized. Photocurrents increased upon self-assembly by up to four orders of magnitude, mostly due to the drastic enhancement of the charge photogeneration. A greatly favorable arrangement of the aromatic cores in the resulting nanostructures, which were characterized by X-ray analysis, may explain these improvements. Photocurrents of mA cm{sup -2}, on/off ratios of 10{sup 4} and quantum efficiencies of unity at low field and light intensity, which are among the best values reported to date, along with the simplicity of fabrication, give this readily-available organic system great potential for use in plastic optoelectronic devices. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Energy Technology Data Exchange (ETDEWEB)
Khaled, K.F. [Electrochemistry Research Laboratory, Chemistry Department, Faculty of Education, Ain Shams University, Roxy, Cairo (Egypt); Materials and Corrosion Laboratory, Chemistry Department, Faculty of Science, Taif University, Taif, 888 Hawiya (Saudi Arabia)], E-mail: khaledrice2003@yahoo.com; Al-Qahtani, M.M. [Materials and Corrosion Laboratory, Chemistry Department, Faculty of Science, Taif University, Taif, 888 Hawiya (Saudi Arabia)
2009-01-15
Corrosion inhibition of aluminum in 1.0 M HCl was investigated in the absence and presence of different concentrations of tetrazole derivatives namely, 1-phenyl-1H-tetrazole-5-thiol (A), 1-phenyl-1H-tetrazole (B), 1H-tetrazol-5-amine (C), 1H-tetrazole (D). Weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements were employed. Impedance measurements showed that the charge transfer resistance increased and double layer capacitance decreased with increase in the inhibitor's concentration. Potentiodynamic polarization study showed that the inhibitors acted as cathodic-type inhibitors. Also, results obtained reveal that compound A is the best inhibitor and the inhibition efficiency (IE%) follows the sequence: A > B > C > D. Obvious correlations were found between corrosion inhibition efficiency and some quantum chemical parameters such as energy of highest occupied molecular orbital (HOMO), energy of lowest unoccupied molecular orbital (LUMO), HOMO-LUMO energy gap and electronic density etc. Calculated results indicated that the difference in inhibition efficiencies between these compounds can be clearly explained in terms of frontier molecular orbital theory. The inhibitor performance depends mainly on the type of function groups substituted on tetrazole ring. The adsorption of these compounds on the aluminum surface obeys a Langmuir adsorption isotherm and has a mixed physisorption and chemisorption mechanism.
International Nuclear Information System (INIS)
Corrosion inhibition of aluminum in 1.0 M HCl was investigated in the absence and presence of different concentrations of tetrazole derivatives namely, 1-phenyl-1H-tetrazole-5-thiol (A), 1-phenyl-1H-tetrazole (B), 1H-tetrazol-5-amine (C), 1H-tetrazole (D). Weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements were employed. Impedance measurements showed that the charge transfer resistance increased and double layer capacitance decreased with increase in the inhibitor's concentration. Potentiodynamic polarization study showed that the inhibitors acted as cathodic-type inhibitors. Also, results obtained reveal that compound A is the best inhibitor and the inhibition efficiency (IE%) follows the sequence: A > B > C > D. Obvious correlations were found between corrosion inhibition efficiency and some quantum chemical parameters such as energy of highest occupied molecular orbital (HOMO), energy of lowest unoccupied molecular orbital (LUMO), HOMO-LUMO energy gap and electronic density etc. Calculated results indicated that the difference in inhibition efficiencies between these compounds can be clearly explained in terms of frontier molecular orbital theory. The inhibitor performance depends mainly on the type of function groups substituted on tetrazole ring. The adsorption of these compounds on the aluminum surface obeys a Langmuir adsorption isotherm and has a mixed physisorption and chemisorption mechanism
Chao, B. F.
2016-05-01
The equivalent water thickness (EWT, including mascon) solutions derived from the GRACE time-variable gravity (TVG) data are gaining recognition. We examine the physics of this practice from first principle in light of the non-uniqueness of 3-D gravitational inversion. We raise caveats on the indiscriminate utilization of the EWT solutions, because a surface EWT solution cannot represent an internal process in a physically meaningful way. In practice, EWT is often a good-enough representation of the reality as the predominant TVG signals do originate from surficial processes such as the water cycle, but it should be recognized that all internal geophysical processes leave signatures to different extent in the TVG observations. Treating all TVG as EWT will render physical quantities in general not directly resolvable by gravity to be misinterpreted. As the TVG observations span longer and improve in precision, the gravity itself, rather than EWT, should still be the quantity of choice. This is not just a problem of model uncertainties or numerical errors, but one in the understanding and treatment in the interest of the rigor of physics.
International Nuclear Information System (INIS)
In this work, we have studied by means of in situ electrical measurements the nucleation, growth and sintering stages of epitaxial YBa2Cu3O6+δ (YBCO) superconducting thin films prepared using a chemical solution deposition approach based on metal-organic trifluoroacetate-based (TFA) precursors. Single crystal substrates (LaAlO3 and CeO2/YSZ) were used in this study. Analysis of isothermal time dependences, at different temperatures, of in situ electrical resistance of films allowed to evidence that the growth rate G is strongly temperature dependent, i.e. G is enhanced by a factor ∼15 when going from 700 to 810 °C. Additionally, we demonstrate that adding Ag-TFA in the solution may enhance the growth rate by as much as 50%, as compared to pure YBCO, thus confirming previous assessments of the strong influence of Ag doping on YBCO film growth and microstructure. In situ electrical resistance measurements show as well that an incubation time exists and we infer the origin of its temperature dependence. Finally, a thermodynamic analysis allows proposing a single equation for the growth rate of YBCO films integrating all the relevant processing parameters. Our analysis has validated the solid-gas reaction-diffusion model describing the growth of YBCO films from TFA precursors and thus enlarges the knowledge required to enhance the control of the microstructure and superconducting properties of solution-derived YBCO films. (paper)
Energy Technology Data Exchange (ETDEWEB)
Herrag, L.; Hammouti, B.; Elkadiri, S.; Aouniti, A. [Laboratoire de Chimie Appliquee et Environnement, LCAE-URAC18, Faculte des Sciences, Universite Mohammed Premier, B.P. 717, M-6000 Oujda (Morocco); Jama, C. [Unite Materiaux et Transformations (UMET), Ingenierie des Systemes Polymeres, CNRS UMR 8207, ENSCL, B.P. 90108, F-59652 Villeneuve d' Ascq Cedex (France); Vezin, H. [Laboratoire de Spectrochimie Infrarouge et Raman (LASIR), UMR-CNRS 8516, Universite des Sciences et Technologies de Lille, Batiment C5, F-59655 Villeneuve d' Ascq Cedex (France); Bentiss, F., E-mail: fbentiss@enscl.f [Laboratoire de Chimie de Coordination et d' Analytique (LCCA), Faculte des Sciences, Universite Chouaib Doukkali, B.P. 20, M-24000 El Jadida (Morocco)
2010-09-15
New diamine derivatives, namely 2-[{l_brace}2-[bis-(2-hydroxyethyl)amino]ethyl{r_brace}(2-hydroxyethyl)amino]ethanol (DAME) and 2-[{l_brace}2-[bis-(2-hydroxyethyl)amino]ethyl{r_brace}(2-hydroxyethyl)amino]propanol (DAMP) were synthesised and their inhibitive action against the corrosion of mild steel in 1 M HCl solution were investigated at 308 K. The detailed study of DAME is given using gravimetric measurements and polarization curves method. Results show that DAME is a good inhibitor and inhibition efficiency reaches 91.7% at 10{sup -3} M. Tafel polarization study revealed that DAME acts as a mixed-type inhibitor. The inhibitor adsorption process in mild steel/DAME/hydrochloric acid system was studied at different temperatures (308-353 K) by means of weight loss measurements. The adsorption of DAME on steel surface obeyed Langmuir's adsorption isotherm. The kinetic and thermodynamic parameters for mild steel corrosion and inhibitor adsorption, respectively, were determined and discussed. The comparative study of inhibitive performance of the two diamine derivatives revealed that DAME is more effective than DAMP. Quantitative Structure-Activity Relationship (QSAR) approach has been conducted in attempt to correlate the corrosion inhibition properties of these diamine derivatives with their calculated quantum chemical parameters.
Energy Technology Data Exchange (ETDEWEB)
Feng, Lijuan [Institute of Chemistry, Northeast Normal University, Changchun 130024 (China); Center of Analytical and Testing, Beihua University, Jilin 132013, P.R China (China); Tong, Cuiyan, E-mail: tongcy959@nenu.edu.cn [Institute of Chemistry, Northeast Normal University, Changchun 130024 (China); He, Yao; Liu, Bingxin; Wang, Chunyu; Sha, Jie [Institute of Chemistry, Northeast Normal University, Changchun 130024 (China); Lü, Changli, E-mail: lucl055@nenu.edu.cn [Institute of Chemistry, Northeast Normal University, Changchun 130024 (China)
2014-02-15
A new fluorescent sensor based on single water-soluble β-cyclodextrin (β-CD) molecule as the support carrier of donor and acceptor complex was designed, and used for TNT detection by fluorescence resonance energy transfer (FRET). In this sensing platform, per-6-amino-β-CD (per-6-NH{sub 2}-β-CD) was used as the detection vehicle. The probe dye of fluorescein 5(6)-isothiocyanate (FITC) was covalently linked onto the per-6-NH{sub 2}-β-CD rim with the grafting molar ratio of 1:1, the residual amino groups of per-6-NH{sub 2}-β-CD can adsorb TNT molecules by forming Meisenheimer complex (TNT–amine complex) with TNT. The absorbtion spectrum of this complex has a spectral overlapping with the emission of FITC in aqueous solution, so it can strongly suppress the fluorescence emission of the adjacent FITC through FRET on β-CD vehicle. This FRET-based fluorescent sensing technique provides a facile, ultrasensitive and selective detection method for TNT molecule. The observed linear fluorescence intensity change could allow the quantitative detection TNT with the detection limit of 20 nM in water. -- Highlights: • Per-6-NH{sub 2}-β-CD was functionalized with fluorescein 5(6)-isothiocyanate. • The PL quenching of FITC-(NH{sub 2})-CD is sensitive to the content of TNT due to FRET. • The PL sensor allows a quantitative detection TNT with a detection limit of 20 nM. • Our strategy opens up a new perspective in the design of sensor for various analytes.
International Nuclear Information System (INIS)
A new fluorescent sensor based on single water-soluble β-cyclodextrin (β-CD) molecule as the support carrier of donor and acceptor complex was designed, and used for TNT detection by fluorescence resonance energy transfer (FRET). In this sensing platform, per-6-amino-β-CD (per-6-NH2-β-CD) was used as the detection vehicle. The probe dye of fluorescein 5(6)-isothiocyanate (FITC) was covalently linked onto the per-6-NH2-β-CD rim with the grafting molar ratio of 1:1, the residual amino groups of per-6-NH2-β-CD can adsorb TNT molecules by forming Meisenheimer complex (TNT–amine complex) with TNT. The absorbtion spectrum of this complex has a spectral overlapping with the emission of FITC in aqueous solution, so it can strongly suppress the fluorescence emission of the adjacent FITC through FRET on β-CD vehicle. This FRET-based fluorescent sensing technique provides a facile, ultrasensitive and selective detection method for TNT molecule. The observed linear fluorescence intensity change could allow the quantitative detection TNT with the detection limit of 20 nM in water. -- Highlights: • Per-6-NH2-β-CD was functionalized with fluorescein 5(6)-isothiocyanate. • The PL quenching of FITC-(NH2)-CD is sensitive to the content of TNT due to FRET. • The PL sensor allows a quantitative detection TNT with a detection limit of 20 nM. • Our strategy opens up a new perspective in the design of sensor for various analytes
Directory of Open Access Journals (Sweden)
M. I. Jacobs
2014-05-01
Full Text Available Isoprene, the most abundant non-methane volatile organic compound (VOC emitted into the atmosphere, is known to undergo gas phase oxidation to form eight different hydroxynitrate isomers in "high NOx" environments. These hydroxynitrates are known to affect the global and regional formation of ozone and secondary organic aerosol (SOA, as well as affect the distribution of nitrogen. In the present study, we have synthesized three of the eight possible hydroxynitrates: 4-hydroxy-3-nitroxy isoprene (4,3-HNI and E/Z-1-hydroxy-4-nitroxy isoprene (1,4-HNI. Oxidation of the 4,3-HNI isomer by the OH radical was monitored using a flow tube chemical ionization mass spectrometer (FT-CIMS, and its OH rate constant was determined to be (3.64 ± 0.41 × 10−11 cm3 molecule−1 s−1. The products of 4,3-HNI oxidation were monitored, and a mechanism to explain the products was developed. An isoprene epoxide (IEPOX – a species important in SOA chemistry and thought to originate only from "low NOx" isoprene oxidation – was found as a minor, but significant product. Additionally, hydrolysis kinetics of the three synthesized isomers were monitored with NMR. The bulk, neutral solution hydrolysis rate constants for 4,3-HNI and the 1,4-HNI isomers were (1.59±0.03 × 10−5 s−1 and (6.76 ± 0.09 × 10−3 s−1, respectively. The hydrolysis reactions of each isomer were found to be general acid-catalyzed. The reaction pathways, product yields and atmospheric implications for both the gas phase and aerosol-phase reactions are discussed.
Jacobs, M. I.; Burke, W. J.; Elrod, M. J.
2014-09-01
Isoprene, the most abundant non-methane volatile organic compound (VOC) emitted into the atmosphere, is known to undergo gas phase oxidation to form eight different hydroxynitrate isomers in "high-NOx" environments. These hydroxynitrates are known to affect the global and regional formation of ozone and secondary organic aerosol (SOA), as well as affect the distribution of nitrogen. In the present study, we have synthesized three of the eight possible hydroxynitrates: 4-hydroxy-3-nitroxy isoprene (4,3-HNI) and E / Z-1-hydroxy-4-nitroxy isoprene (1,4-HNI). Oxidation of the 4,3-HNI isomer by the OH radical was monitored using a flow tube chemical ionization mass spectrometer (FT-CIMS), and its OH rate constant was determined to be (3.64 ± 0.41) × 10-11 cm3 molecule-1 s-1. The products of 4,3-HNI oxidation were monitored, and a mechanism to explain the products was developed. An isoprene epoxide (IEPOX) - a species important in SOA chemistry and thought to originate only from "low-NOx" isoprene oxidation - was found as a minor, but significant, product. Additionally, hydrolysis kinetics of the three synthesized isomers were monitored with nuclear magnetic resonance (NMR). The bulk, neutral solution hydrolysis rate constants for 4,3-HNI and the 1,4-HNI isomers were (1.59 ± 0.03) × 10-5 s-1 and (6.76 ± 0.09) × 10-3 s-1, respectively. The hydrolysis reactions of each isomer were found to be general acid-catalyzed. The reaction pathways, product yields and atmospheric implications for both the gas phase and aerosol phase reactions are discussed.
Directory of Open Access Journals (Sweden)
Syed Hussinien H Shah
Full Text Available Exotic functions of antifreeze proteins (AFP and antifreeze glycopeptides (AFGP have recently been attracted with much interest to develop them as commercial products. AFPs and AFGPs inhibit ice crystal growth by lowering the water freezing point without changing the water melting point. Our group isolated the Antarctic yeast Glaciozyma antarctica that expresses antifreeze protein to assist it in its survival mechanism at sub-zero temperatures. The protein is unique and novel, indicated by its low sequence homology compared to those of other AFPs. We explore the structure-function relationship of G. antarctica AFP using various approaches ranging from protein structure prediction, peptide design and antifreeze activity assays, nuclear magnetic resonance (NMR studies and molecular dynamics simulation. The predicted secondary structure of G. antarctica AFP shows several α-helices, assumed to be responsible for its antifreeze activity. We designed several peptide fragments derived from the amino acid sequences of α-helical regions of the parent AFP and they also showed substantial antifreeze activities, below that of the original AFP. The relationship between peptide structure and activity was explored by NMR spectroscopy and molecular dynamics simulation. NMR results show that the antifreeze activity of the peptides correlates with their helicity and geometrical straightforwardness. Furthermore, molecular dynamics simulation also suggests that the activity of the designed peptides can be explained in terms of the structural rigidity/flexibility, i.e., the most active peptide demonstrates higher structural stability, lower flexibility than that of the other peptides with lower activities, and of lower rigidity. This report represents the first detailed report of downsizing a yeast AFP into its peptide fragments with measurable antifreeze activities.
Energy Technology Data Exchange (ETDEWEB)
Lopez G, O. G.
2010-07-01
This work presents a study about the synthesis by plasma, the electric properties and superficial interaction of polymers derived from pyrrole doped with Iodine with potential use as bio material. Poly-pyrrole is a semiconductor and biocompatible polymer with potential application in the development of artificial muscles and implants where the electric interaction between cells and material is an important variable. The syntheses were made at 13.5 MHz in a glass tubular reactor of 1500 cm{sup 3} with electrodes of 6.5 cm diameter and stainless steel flanges. An electrode was connected to the RF terminal of the power supply that is combined with a matching coupling resistance. The monomer and dopant used in this work were pyrrole and Iodine respectively, in closed containers. They were vaporized and injected separately into the reactor at room temperature and 0.1 mbar. The vapors of the reagents mixed freely in the reactor. The synthesis time was 240 min at 40, 60, 80 and 100 W. The polymers were obtained as thin films adhered to the reactor walls. The films were washed and swollen with distilled water and removed from the reactor walls with a small spatula. The polymers were irradiated with gamma rays at 18 and 22 KGy. Due to the fact that the doses are cumulative, the final dose applied was 40 KGy. The polymers characterization was carried out by Fourier Transform Infrared Spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy, contact angle, electrical conductivity and X-ray diffraction. The analyses indicates that the polymers have very similar structure in almost the entire power range, showing C-O, C=C, C-H, O-H, N-H bonds with a predominantly amorphous structure. The TGA analyses showed that the material has 4 or 5 loses of material. The first one starts after that 115 C except for the material irradiated at 40 KGy, this one begins in 87 C, the second one is in the interval of 196 and 295 C, the third one between 311 and 500 C, and the
International Nuclear Information System (INIS)
Metal-organic frameworks (MOFs) UiO-66 and its amine derivative (UiO-66-NH2) with high surface area and unprecedented chemical stability were synthesized and first explored for U(VI) capture from aqueous solutions. At pH 5.5, U(VI) sorption reach equilibrium in ca. 4 h and the maximum sorption capacity is more than 100 mg g-1. Moreover, they show desirable selectivity towards U(VI) over a range of competing metal ions. Sorption results demonstrate that introduction of amino groups into MOFs does not enhance U(VI) sorption, probably result from the lower activity of aromatic amines, decrease of surface area and formation of intermolecular hydrogen bonds. (author)
Indian Academy of Sciences (India)
Kyu-Seog Hwang; Bo-An Kang; Sung-Dai Kim; Seung Hwangbo; Jim-Tae Kim
2011-08-01
3 Mol% of europium doped strontium aluminate (SrAl2O4:Eu2+) coatings on silicon substrates were prepared by electrostatic spray deposition method using a salted sol–gel derived solution as a starting material. Asdeposited films at 100°C for 5 h were heated at 1100°C for 2 h under a reducing ambient atmosphere of 95%N2 + 5%H2 . Nanocrystalline SrAl2O4 film was confirmed by surface morphological and crystallographic analyses. Monitored at 520 nm, the excitation spectrum showed a broad band from 300 ∼ 500 nm and the emission intensity showed a maximum yellow peak intensity at 512 nm with a broad band from 460 ∼ 610 nm.
International Nuclear Information System (INIS)
Highlights: •Pyridine-2-thiol, P2T, and 2-Pyridyl disulfide, 2PD, are good inhibitors. •P2T and 2PD reveal 98% efficiency in 200 mg/L concentration at stagnant condition. •Langmuir isotherm shows both physisorption and chemisorption types for inhibitors. •Mild steel corrosion rate decreases with rising rotation speed in blank solution. •Hydrodynamic flow has a destructive effect on inhibitors performance. -- Abstract: In this study, the inhibitive performance of two pyridine derivatives as corrosion inhibitors for mild steel was examined under stagnant condition and hydrodynamic flow in HCl solution at 25 °C. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques were employed. To explore the inhibitors adsorption mechanism, Langmuir isotherm and quantum chemical studies were used. The results of electrochemical measurements show that the inhibitor concentration has a positive effect on its efficiency while for hydrodynamic condition, it is vice versa. Corrosion attack morphologies were observed at stagnant and hydrodynamic conditions to verify qualitatively the results obtained by electrochemical methods
Directory of Open Access Journals (Sweden)
Joshua N. Edokpayi
2015-12-01
Full Text Available Pb2+ is considered to be a very toxic pollutant in the aquatic environmental media. Biopolymeric chitosan synthesized from snail shell has been studied for its potential to remove heavy metals from aqueous solution. The experiments were conducted in the range of 1–50 mg/L initial Pb2+ concentration at 298 K. The effects of pH, adsorbent dosage and contact time on the adsorptive property of the adsorbent were investigated and optimized. The derived chitosan was characterized using Fourier transform infrared spectrometer (FT-IR and X-ray florescence (XRF. The experimental data obtained were analysed using the Langmuir and Freundlich adsorption isotherm models. The Langmuir model and pseudo second order kinetic model suitably described the adsorption and kinetics of the process with regression coefficient of 0.99 and 1.00, respectively. Sodium hydroxide was a better desorbing agent than hydrochloric acid and de-ionized water. From the results obtained, it is concluded that synthesized biopolymers from land snail shells has the potential for the removal of Pb2+ from aqueous solutions.
International Nuclear Information System (INIS)
In order to develop a new method for the preparation of the [99Tcm(CO)2(NO)-L] (L=DTPA, EDTA, EHIDA) complexes in aqueous solution, two different procedures were developed: one is formation of the metal-tricarbonyl-ligand complex and subsequent nitrosylation; another is nitrosylation of the metal-tricarbonyl precursor followed by reaction with the ligand. The optimal labeling conditions were studied. Results of TLC and HPLC indicate that the radiochemical yields derived from the two methods list above are all more than 90%. It's an easier new way to prepare [99Tcm(CO)2(NO)-L] complexes in aqueous solution with high efficiency. The newly developed [99Tcm(CO)2(NO)-L] complexes are stable at room temperature during 1 half-life of the isotope. At the same time, the lipophility and net charge of [99Tcm(CO)2(NO)-L] complexes are also changed comparing with that of corresponding [99Tcm(CO)3]+ core complexes. It opens a new field for designing radiopharmaceuticals. (authors)
International Nuclear Information System (INIS)
A “bottom up” approach of manufacturing graphite oxides (GOs) derived from aqueous glucose solutions by virtue of an environmentally-friendly process and the way of in-situ synthesizing magnetite–GOs composites are described in this work in detail. The dehydrations among glucose molecules under hydrothermal condition result in the initial carbon quantum dots and ultimate GOs. The structural information of the GOs is obtained by the infrared, ultraviolet–visible and X-ray photoelectron spectra. The magnetite–GOs composites were obtained by a one-pot method under the same hydrothermal conditions as the one of preparing GOs. The composites perform high activities in catalytic degradation of Rhodamine B in the presence of hydrogen peroxides without extra heating or pH adjusting. Both the GOs and the magnetite–GOs composites are also assured by measurements of transmission electron microscope and X-ray powder diffraction. - Highlights: • Graphite oxides are made from aqueous glucose solutions by hydrothermal reaction. • A way of in-situ synthesizing composites of magnetite–graphite oxides is depicted. • The composites perform high activities in catalytic degradation of Rhodamine B
Geiger, Yasmin; Gottlieb, Hugo E; Akbey, Ümit; Oschkinat, Hartmut; Goobes, Gil
2016-05-01
Smart materials are created in nature at interfaces between biomolecules and solid materials. The ability to probe the structure of functional peptides that engineer biogenic materials at this heterogeneous setting can be facilitated tremendously by use of DNP-enhanced solid-state NMR spectroscopy. This sensitive NMR technique allows simple and quick measurements, often without the need for isotope enrichment. Here, it is used to characterize a pentalysine peptide, derived from a diatom's silaffin protein. The peptide accelerates the formation of bioinspired silica and gets embedded inside the material as it is formed. Two-dimensional DNP MAS NMR of the silica-bound peptide and solution NMR of the free peptide are used to derive its secondary structure in the two states and to pinpoint some subtle conformational changes that the peptide undergoes in order to adapt to the silica environment. In addition, interactions between abundant lysine residues and silica surface are identified, and proximity of other side chains to silica and to neighboring peptide molecules is discussed. PMID:26451953
Energy Technology Data Exchange (ETDEWEB)
Zaghbani, Asma [Laboratoire Eau et Technologies Membranaires, CERTE, BP 273, 8020 Soliman (Tunisia); Fontas, Claudia [Department of Chemistry, University of Girona, 17071 Girona (Spain)], E-mail: claudia.fontas@udg.edu; Hidalgo, Manuela [Department of Chemistry, University of Girona, 17071 Girona (Spain); Tayeb, Rafik; Dhahbi, Mahmoud [Laboratoire Eau et Technologies Membranaires, CERTE, BP 273, 8020 Soliman (Tunisia); Vocanson, Francis; Lamartine, Roger [Universite de Lyon, Lyon, F-69003 (France); Universite Lyon 1, Villeurbanne, F-69622 (France); CNRS, UMR 5246, ICBMS, equipe CSAp, 43 boulevard du 11 novembre 1918, Villeurbanne, F-69622 (France); Seta, Patrick [Institut Europeen des Membranes, UMR CNRS 5635, 1919 route de Mende, 34293 Montpellier (France)
2008-07-01
The complexation abilities of different thiacalix[4]arene derivatives towards some rare earth metal ions, metallic pollutants, and noble metals have been investigated in liquid-liquid experiments. Thiacalix[4]arene dissolved in chloroform effectively extracts Pd(II) (in acidic chloride media) and also Ag(I), Cd(II), Sm(III) and Ce(III), all buffered at pH 6 or 8. The modification of this compound to form an amide derivative results in an effective extraction of noble metals, ranked according to Au(III) > Pd(II) > Pt(IV) > Ag(I). Moreover, a supported liquid membrane system for silver transport has been developed based on thiacalix[4]arene dissolved in NPOE, and parameters affecting its efficiency have been investigated, such as the stripping composition and the pH of the feed solution. Finally, the selectivity of the membrane system has been evaluated by using as feed sources mixtures of silver and other metal ion000.
Energy Technology Data Exchange (ETDEWEB)
El-Attar, Mona A.; Ghoneim, Mohamed M. [Analytical Chemistry Research Unit, Chemistry Department, Tanta University (Egypt); Ismail, Iqbal M., E-mail: maema.2011@yahoo.com [Chemistry Department, Faculty of Science, King Abdul Aziz University, Jeddah (Saudi Arabia)
2012-08-15
Two azo-compounds, 2-methyl-4-(5-amino-2-hydroxy-phenylazo)-quinoline (2) and 2-methyl-4-(2-hydroxy-5-nitrophenylazo)-quinoline, derived from 4-amino-2-methylquinoline were synthesized. Their chemical structures were characterized and confirmed by means of elemental chemical analysis, infrared (IR) spectroscopy, {sup 1}H nuclear magnetic resonance (NMR) and mass spectrometry (MS). The electrochemical behavior of the starting compound (4-amino-2-methylquinoline) and of the two synthesized azo-derivatives was studied at the mercury electrode in the B-R universal buffer at various pH values (2-11.5) containing 40% (v/v) ethanol using dc-polarography, cyclic voltammetry and controlled-potential coulometry. Their electrode reaction pathways were elucidated and discussed. The dissociation constants (pKa) of the examined compounds, stability constants and stoichiometry of their complexes in solution with some transition metal ions (Co(II), Ni(II), Cu(II), La(III) and UO{sup 2+}{sub 2}) were determined. (author)
International Nuclear Information System (INIS)
The complexation abilities of different thiacalix[4]arene derivatives towards some rare earth metal ions, metallic pollutants, and noble metals have been investigated in liquid-liquid experiments. Thiacalix[4]arene dissolved in chloroform effectively extracts Pd(II) (in acidic chloride media) and also Ag(I), Cd(II), Sm(III) and Ce(III), all buffered at pH 6 or 8. The modification of this compound to form an amide derivative results in an effective extraction of noble metals, ranked according to Au(III) > Pd(II) > Pt(IV) > Ag(I). Moreover, a supported liquid membrane system for silver transport has been developed based on thiacalix[4]arene dissolved in NPOE, and parameters affecting its efficiency have been investigated, such as the stripping composition and the pH of the feed solution. Finally, the selectivity of the membrane system has been evaluated by using as feed sources mixtures of silver and other metal ions
Yousfi, Ammar; Mechergui, Mohammed
2016-04-01
al. (2001). In this work, a novel solution based on theoretical approach will be adapted to incorporate both the seepage face and the unsaturated zone flow contribution for solving ditch drained aquifers problems. This problem will be tackled on the basis of the approximate 2D solution given by Castro-Orgaz et al. (2012). This given solution yields the generalized water table profile function with a suitable boundary condition to be determined and provides a modified DF theory which permits as an outcome the analytical determination of the seepage face. To assess the ability of the developed equation for water-table estimations, the obtained results were compared with numerical solutions to the 2-D problem under different conditions. It is shown that results are in fair agreement and thus the resulting model can be used for designing ditch drainage systems. With respect to drainage design, the spacings calculated with the newly derived equation are compared with those computed from the DF theory. It is shown that the effect of the unsaturated zone flow contribution is limited to sandy soils and The calculated maximum increase in drain spacing is about 30%. Keywords: subsurface ditch drainage; unsaturated zone; seepage face; water-table, ditch spacing equation
Energy Technology Data Exchange (ETDEWEB)
Obradors, X., E-mail: Xavier.obradors@icmab.es [Institut de Ciencia de Materials de Barcelona (ICMAB-CSIC), Campus Universitat Autonoma de Barcelona, 08193 Bellaterra (Spain); Martinez-Julian, F.; Zalamova, K.; Vlad, V.R.; Pomar, A.; Palau, A.; Llordes, A.; Chen, H.; Coll, M.; Ricart, S.; Mestres, N.; Granados, X.; Puig, T. [Institut de Ciencia de Materials de Barcelona (ICMAB-CSIC), Campus Universitat Autonoma de Barcelona, 08193 Bellaterra (Spain); Rikel, M. [Nexans Superconductors, 50354 Huerth (Germany)
2012-11-20
After briefly reviewing the present understanding of the nucleation process of YBCO films, a new approach is presented to enhance the stability of c-axis nucleation in epitaxial chemical solution deposited YBCO thin films derived from TFA precursors. We show that with silver addition to the TFA precursor c-axis nucleation can be reached in a wide range of temperature thus keeping high percolating J{sub c}. We argue that silver reduces supersaturation and makes more stable the c-axis nuclei without modifying T{sub c}. Additional advantages of silver addition are an enhanced surface smootheness and a reduced porosity of the YBCO films. The second reported topic relates to the discovery of an adverse relationship between percolating J{sub c} and YBCO films mesostrain, as determined through X-ray diffraction line broadening. We show that mesostrain is enhanced in processes leading to inefficient strain healing at grain boundaries, for instance annealing times too short or growth temperatures too low. It is suggested that the strained regions at the low angle grain boundaries lead to a weak link behavior which can be microscopically understood on the basis of pair formation prevention, as proposed by the bond contraction pairing model.
Rauf, Muhammad Khawar; Zaib, Sumera; Talib, Ammara; Ebihara, Masahiro; Badshah, Amin; Bolte, Michael; Iqbal, Jamshed
2016-09-15
A facile and robust microwave-assisted solution phase parallel synthesis protocol was exercised for the development of a 38-member library of N,N'-disubstituted thiourea analogues (1-38) by using an identical set of conditions. The reaction time for synthesis of N,N'-disubstituted thiourea analogues was drastically reduced from a reported duration of 8-12h for conventional methods to only 1.5-2.0min. All the derivatives (1-38) were characterized by physico-analytical techniques such as elemental analysis in combination with FT-IR, (1)H, (13)C NMR and by single crystal XRD analysis have also been performed. These compounds were screened for their in vitro urease inhibition activities. Majority of compounds exhibited potent urease inhibition activities, however, the most significant activity was found for 16, with an IC50 value of 1.23±0.1μM. Furthermore, the synthesized compounds were screened for their cytotoxic potential against lungs cancer cell lines. Cell culture studies demonstrated significant toxicity of the compounds on the cell lines, and the levels of toxicity were altered in the presence of various side groups. The molecular docking studies of the most potent inhibitors were performed to identify the probable binding modes in the active site of the urease enzymes. These compounds have a great potential and significance for further investigations. PMID:27480030
Directory of Open Access Journals (Sweden)
Zaira Zaman Chowdhury,
2012-05-01
Full Text Available The feasibility of granular activated carbon (GAC derived from Mangostene (Mangostana garcinia fruit shell to remove lead, Pb2+ cations was investigated in batch and fixed bed sorption systems. Batch experiments were carried out to study equilibrium isotherms, kinetics, and thermodynamics by using an initial lead (Pb2+ ions concentration of 50 to 100 mg/L at pH 5.5. Equilibrium data were fitted using Langmuir, Freundlich, and Temkin linear equation models at temperatures 30°C, 50°C, and 70°C. Langmuir maximum monolayer sorption capacity was 25.00 mg/g at 30°C. The experimental data were best represented by pseudo-second-order and Elovich models. The sorption process was found to be feasible, endothermic, and spontaneous. In column experiments, the effects of initial cation concentration (50 mg/L, 70 mg/L, and 100 mg/L, bed height (4.5 cm and 3 cm, and flow rate (1 mL/min and 3 mL/min on the breakthrough characteristics were evaluated. Breakthrough curves were further analyzed by using Thomas and Yoon Nelson models to study column dynamics. The column was regenerated and reused consecutively for four cycles. The result demonstrated that the prepared activated carbon was suitable for removal of Pb2+ from synthetic aqueous solution using batch, as well as fixed bed sorption systems.
International Nuclear Information System (INIS)
Highly crystalline epitaxial Ba0.8Sr0.2TiO3 (BST) thin-films are grown on (001)-oriented LaNiO3-buffered LaAlO3 substrates by pulsed laser irradiation of solution derived barium-zirconium-titanium precursor layers using a UV Nd:YAG laser source at atmospheric conditions. The structural analyses of the obtained films, studied by X-ray diffractometry and transmission electron microscopy, demonstrate that laser processing allows the growth of tens of nm-thick BST epitaxial films with crystalline structure similar to that of films obtained through conventional thermal annealing methods. However, the fast pulsed nature of the laser employed leads to crystallization kinetic evolution orders of magnitude faster than in thermal treatments. The combination of specific photothermal and photochemical mechanisms is the main responsible for the ultrafast epitaxial laser-induced crystallization. Piezoresponse microscopy measurements demonstrate equivalent ferroelectric behavior in laser and thermally annealed films, being the piezoelectric constant ∼25 pm V−1
Evenepoel, Pieter; de Loor, Henriette; Delcour, Jan A.; Courtin, Christophe M.; Kuypers, Dirk; Augustijns, Patrick; Verbeke, Kristin; Meijers, Björn
2016-01-01
The colonic microbial metabolism is a key contributor to uremic retention solutes accumulating in patients with CKD, relating to adverse outcomes and insulin resistance. Whether prebiotics can reduce intestinal generation of these microbial metabolites and improve insulin resistance in CKD patients not yet on dialysis remains unknown. We performed a randomized, placebo-controlled, double-blind, cross-over study in 40 patients with eGFR between 15 and 45 ml/min/1.73 m2. Patients were randomized to sequential treatment with prebiotic arabinoxylan oligosaccharides (AXOS) (10 g twice daily) and maltodextrin for 4 weeks, or vice versa, with a 4-week wash-out period between both intervention periods. Serum levels and 24h urinary excretion of p-cresyl sulfate, p-cresyl glucuronide, indoxyl sulfate, trimethylamine N-oxide and phenylacetylglutamine were determined at each time point using liquid chromatography—tandem mass spectrometry. In addition, insulin resistance was estimated by the homeostatic model assessment (HOMA-IR). A total of 39 patients completed the study. We observed no significant effect of AXOS on serum p-cresyl sulfate (P 0.42), p-cresyl glucuronide (P 0.59), indoxyl sulfate (P 0.70) and phenylacetylglutamine (P 0.41) and a small, albeit significant decreasing effect on serum trimethylamine N-oxide (P 0.04). There were neither effect of AXOS on 24h urinary excretion of p-cresyl sulfate (P 0.31), p-cresyl glucuronide (P 0.23), indoxyl sulfate (P 0.87) and phenylacetylglutamine (P 0.43), nor on 24h urinary excretion of trimethylamine N-oxide (P 0.97). In addition, we observed no significant change in HOMA-IR (P 0.93). In conclusion, we could not demonstrate an influence of prebiotic AXOS on microbiota derived uremic retention solutes and insulin resistance in patients with CKD not yet on dialysis. Further study is necessary to elucidate whether prebiotic therapy with other characteristics, higher cumulative exposure or in different patient populations may
Noller, Johannes
2012-01-01
We consider generalized chameleon models where the conformal coupling between matter and gravitational geometries is not only a function of the chameleon field \\phi, but also of its derivatives via higher order co-ordinate invariants. Specifically we consider the first such non-trivial conformal factor A(\\phi,X), where X is the canonical kinetic term for \\phi. The associated phenomenology is investigated and we show that such theories have a new generic mass-altering mechanism, potentially assisting the generation of a sufficiently large chameleon mass in dense environments. The most general effective potential is derived for such derivative chameleon setups and explicit examples are given. Interestingly this points us to the existence of a purely derivative chameleon protected by a shift symmetry for \\phi. We also discuss potential ghost-like instabilities associated with mass-lifting mechanisms and find another, mass-lowering and instability-free, branch of solutions. This suggests that, barring fine-tuning...
Brizuela, Alicia B.; Raschi, Ana B.; Castillo, María V.; Davies, Lilian; Romano, Elida; Brandán, Silvia A.
2014-09-01
In this study, aqueous solutions at different molar concentrations of sodium cyclamate in water were completely characterized by HATR (Horizontal Attenuated Total Reflectance) and Raman spectroscopies. The theoretical structures of cyclamate ion, the zwitterionic and neutral forms of the cyclamic acid and its dimer were optimized in gas and aqueous solution phases by using the hybrid B3LYP/6-31G* method. The solvent effects for the four species in aqueous solutions were simulated by using self-consistent reaction field (SCRF) calculations employing the integral equation formalism variant (IEFPCM) model. The complete assignments of the vibrational spectra of all the forms of cyclamic acid were performed taking into account the factor group analysis with the Scaled Quantum Mechanics Force Field (SQMFF) methodology. The existence of the zwitterionic and neutral forms of the cyclamic acid and its dimer in a solution of cyclamate in water is evidenced by characteristic bands in the HATR and Raman spectra. The dimerization of cyclamate in aqueous solution was previously reported by conductimetric method. The natural population analysis (NPA) and Merz-Kollman (MK) charges, molecular electrostatic potential (MEP), natural bond orbital (NBO) and atoms in molecules (AIM) calculations predict for all the species the principal donor and acceptor sites for the H bonds formation in aqueous solution. The SQM force fields for the cyclamate ion, the zwitterionic and neutral species of the cyclamic acid were obtained and their corresponding force constants in both phases were reported. Additionally, the solvation energies for those species were reported.
Yong Zhang; Charalambos Papelis; Young, Michael H.; Markus Berli
2013-01-01
Heterogeneous media consisting of segregated flow regions are fractional-order systems, where the regional-scale anomalous diffusion can be described by the fractional derivative model (FDM). The standard FDM, however, first, cannot characterize the Darcy-scale dispersion through repacked sand columns, and second, the link between medium properties and model parameters remains unknown. To fill these two knowledge gaps, this study applies a tempered fractional derivative model (TFDM) to captur...
International Nuclear Information System (INIS)
A possible classical route conducting towards a general relativity theory with higher-derivatives starting, in a sense, from first principles, is analysed. A completely causal vacuum solution with the symmetries of the Goedel universe is obtained in the framework of this higher-derivative gravity. This very peculiar and rare result is the first known vcuum solution of the fourth-order gravity theory that is not a solution of the corresponding Einstein's equations.(Author)
International Nuclear Information System (INIS)
Date pits (DP) as a huge solid waste in Egypt is of little or no economic value and in fact present a disposal problem. The quantity of DP has been estimated to million tons per year. DP was used for preparation of physically and chemically activated carbons. The raw materials were physically activated with pure steam, steam with flow of nitrogen gas or steam with current of air, while the chemically activated samples were prepared by impregnation of 10% ferric chloride or 10% calcium acetate. The effect of various factors, e.g., carbon type, carbon dosage, ph, initial concentration, temperature, and various inorganic ions on the adsorption capacity, were quantitatively determined. The two-parameters equilibrium models Langmuir and Freundlich equations were discussed. In this work, analyses and batch adsorption experiments have been carried out to characterize and to understand adsorption mechanism by modeling the adsorption kinetics. The present study deals with the factors affecting the uptake of Pb2+, Cd2+, Fe3+, and Sr2+ ions from aqueous solution using activated carbon developed from locally available material DP, by one-step steam pyrolysis in a batch mode. Concurrently removal of these cations from aqueous medium are affected by the presence of other ions e.g. NO3-, CO3-, SO4- and masking agents e.g. oxalic acid and EDTA in solution. Uptake values are decreased with increasing the concentration of these ions in solution heavy metals
Energy Technology Data Exchange (ETDEWEB)
Wang, Liwei, E-mail: liweiwangy@hotmail.com [Department of Chemistry and Chemical Engineering, Minjiang University, Fuzhou 350108 (China); Egerton, Terry A., E-mail: terry.egerton@ncl.ac.uk [School of Chemical Engineering and Advanced Materials, Newcastle University, Newcastle NE1 7RU (United Kingdom)
2014-10-15
The influence of the concentration of aqueous TiCl{sub 4} solution on the phase formation, morphology and particle size of the titanium dioxide hydrolysis product was investigated by XRD and TEM. Significant features, observed in the Raman spectra of the TiCl{sub 4} solutions with a concentration >3 M, demonstrated that the TiCl{sub 4} had hydrolysed. As the formal concentration of TiCl{sub 4} decreased from 4.98 to 1 M, the Raman spectra changed qualitatively. Despite the changes in the Raman spectra of these precursor solutions, the TiO{sub 2} product was mainly rutile in all cases. However, at low TiCl{sub 4} concentrations small amounts of anatase were also observed. Electron microscopy suggested that the anatase particles were significantly smaller than the rutile and also indicated increasing aggregation of the product from the more dilute TiCl{sub 4} solutions. The optical properties and photoactivities of the TiO{sub 2} powders prepared at different concentrations were also investigated. The powder synthesized from 5 M TiCl{sub 4} showed the highest UV extinction. The photoactivity of the product, determined by the photocatalytic oxidation of propan-2-ol (isopropanol) to propanone (acetone), was not significantly modified by changes in the concentration of the starting TiCl{sub 4}. The possibility that the relatively low area of most rutiles contributes to the reported photocatalytic activity of rutile being lower than that of anatase is discussed. - Highlights: • Properties of TiO{sub 2} made from TiCl{sub 4} of decreasing concentration are reported. • Raman spectra change as TiCl{sub 4} concentrations decrease from 5 to 2.5 M. • Rutile is the major product from hydrolysis of 1 M–5 M TiCl{sub 4} solutions. • Optical properties are changed. • Activity for photocatalysis of propan-2-ol is unaltered.
International Nuclear Information System (INIS)
Graft copolymers were prepared by 60Co-γ irradiation of binary mixture of ethyl cellulose (EC) and acrylonitrile (AN). Conversion %-dose graphs were obtained, and 95% copolymer yield has been reached at around 8 kGy dose. Conversion of nitrile groups to amidoxime (AO) were achieved by aqueous solutions of NH2OH.HCl-NaOH at 50 C. The amidoxime conversion was followed by using FT-IR spectrophotometer and determined as percentage. After 72 h period, nearly 100% amidoxime conversion was provided. The structures of EC-g-AN and EC-g-AO were characterized by FTIR/ATR, TGA, and SEM methods.
Al-Maythalony, Bassem A.; Wazeer, Mohammed I. M.; Isab, Anvarhusein A.; Nael, M. T.; Ahmad, Saeed
2008-01-01
Reactions of imidazolidine-2-thione (Imt), 1,3-diazinane-2-thione (Diaz) and 1,3-diazipane-2-thione (Diap) with Cd(SeCN)2 in acetonitrile resulted in the formation of 2:1 tetrahedral complexes. Both solid state and solution NMR, confirm the exocyclic thione atom to be the donor in all cases. 113Cd shielding tensors and anisotropies were calculated from the solid-state NMR spectra. Based on the solid NMR data, a distorted tetrahedral dispositions of ligands around cadmium is proposed for the I...
Qiang, Yujie; Zhang, Shengtao; Xu, Shenying; Li, Wenpo
2016-06-15
Corrosion experiments and theoretical calculations were performed to investigate the inhibition mechanism of indazole (IA) and 5-aminoindazole (AIA) for copper in NaCl solution. The results obtained from weight loss and electrochemical experiments are in good agreement, and reveal that these compounds are high-efficiency inhibitors with inhibition efficiency order: AIA>IA, which was further confirmed by field emission scanning electronic microscope (FESEM) observation. Besides, the quantum chemical calculations and molecular dynamics (MD) simulation showed that both studied inhibitors are adsorbed strongly on the copper surface in parallel mode. The adsorption of these molecules on copper substrate was found to obey Langmuir isotherm. PMID:27003499
Institute of Scientific and Technical Information of China (English)
LI Song-mei; ZHANG Hong-rui; LIU Jian-hua
2007-01-01
The corrosion behavior of aluminum alloy 2024-T3 was studied in 3.5% NaCl solution with two fluorescence quinoline compounds named 8-hydroxy-quinoline(8HQ) and 8-hydroxy-quinoline-5-sulfonic acid(HQS). The open circuit potential(OCP) test result indicates that both compounds change the alloy corrosion potential by adsorbing on the electrode surface. Polarization measurements show that 8HQ is a mixed type inhibitor by blocking the active sites of the metal surface, while HQS is a corrosion accelerator by activating the cathodic reaction. Changes of the impedance parameters in the electrochemical impedance spectroscopy(EIS) are related to the adsorption of 8HQ on the metal surface, which leads to the formation of a protective layer. The impedance diagram in the solution with HQS is similar to the one without additional organic compounds. The morphology and composition of the protective layer were studied by using SEM/EDS. The result confirms the function of the additions that the effect of 8HQ is due to the insoluble aluminum chelate, Al(HQ)3, to prevent adsorption of chloride ion, while the effect of HQS is to break down the oxide film.
Müller-Maatsch, Judith; Bechtold, Lena; Schweiggert, Ralf M; Carle, Reinhold
2016-12-15
Pelargonidin-based colors suffer from notorious instability. A phenolic mango peel extract and defined phenolic fractions thereof were shown to effectively modulate the visible absorption of anthocyanins from strawberry (Fragaria x ananassa Duch.) and red radish (Raphanus sativus L.) by intermolecular co-pigmentation. Consistently, non-acylated pelargonidin derivatives from strawberry exerted significantly greater hyper- and bathochromic spectral shifts than their acylated counterparts from red radish. The addition of low molecular-weight co-pigments such as gallic acid and monogalloyl glucoses to strawberry anthocyanins led to strong hyperchromic shifts from 30% to 48%, while gallotannins (>six galloyl units) exerted smaller co-pigmentation effects (36±2%; Δλmax 13nm), possibly due to steric hindrances. In contrast, penta- and hexa-O-galloyl-glucose induced greatest and most stable co-pigmentation effects (53±2%; Δλmax 13nm). Irrespective of the underlying mechanisms and the responsible compounds, phenolic mango peel extracts might represent suitable color enhancers for coloring foodstuff, particularly for those containing non-acylated pelargonidin derivatives. PMID:27451227
Reineker, P.; Kühne, R.
1980-03-01
Starting from the stochastic Liouville equation of the full Haken-Strobl model, describing the coupled coherent and incoherent motion of excitons in molecular crystals, the Nakajima-Zwanzig generalized master equation (GME) for the probability of finding an exciton at a specific lattice site is derived by an exact straightforward evaluation of its memory function. Various recently derived generalized master equations describing the excition motion are obtained as limiting cases and the Born approximation is discussed. It is shown that, even in the case of nearest-neighbor interaction in the stochastic Liouville equation, in the GME generalized time-dependent transition rates evolve between non-nearest neighbors and that their time behavior shows damped oscillations. Applying the Born approximation to the GME, the range of the generalized transition rates reduces to that of the interaction in the stochastic Liouville equation. Furthermore in this approximation the transition rates show a purely exponential decay with increasing time. Taking into account the interaction with an arbitrary number of neighbors, the mean square displacement of the exciton motion is calculated exactly from the GME. Finally the GME is solved exactly in the general case and several limiting expressions are discussed.
International Nuclear Information System (INIS)
We present a systematic investigation of two coinciding lattices and their spatial beating frequencies that lead to the formation of moiré patterns. A mathematical model was developed and applied for the case of a hexagonally arranged adsorbate on a hexagonal support lattice. In particular, it describes the moiré patterns observed for graphene grown on a hexagonally arranged transition metal surface, a system that serves as one of the promising synthesis routes for the formation of this highly wanted material. The presented model uses a geometric construction that derives analytic expressions for first and higher order beating frequencies occurring for arbitrarily oriented graphene on the underlying substrate lattice. By solving the corresponding equations, we predict the size and orientation of the resulting moiré pattern. Adding the constraints for commensurability delivers further solvable analytic equations that predict whether or not first or higher order commensurable phases occur. We explicitly treat the case for first, second and third order commensurable phases. The universality of our approach is tested by comparing our data with moiré patterns that are experimentally observed for graphene on Ir(111) and on Pt(111). Our analysis can be applied for graphene, hexagonal boron nitride (h-BN), or other sp2-networks grown on any hexagonally packed support surface predicting the size, orientation and properties of the resulting moiré patterns. In particular, we can determine which commensurate phases are expected for these systems. The derived information can be used to critically discuss the moiré phases reported in the literature. (paper)
International Nuclear Information System (INIS)
Single crystals of (1 - x)BaTiO3 + xNaNbO3 (BTNN) for x = 0.84 were obtained by high temperature solution growth using Na2B4O7 as solvent. The room temperature crystal structure of BTNN 16/84-phase was determined from X-ray single crystal diffraction data, in the tetragonal system with space group P4bm. The refinement from 246 independent reflections led to the following parameters: a = b = 5.5845(3) A, c = 3.9453(2) A, V = 123.041(11) A3, Z = 2, with final cRwp = 0.150 and RB = 0.041. The structure of BTNN 16/84-phase can be described as a three-dimensional framework built up from (Nb-Ti)O6 octahedra with Na and Ba in the dodecahedral site of perovskite-like type. Some mm3-sized crystals have been selected and various dielectric measurements (ferroelectric, pyroelectric, and piezoelectric) have been performed. Transition from paraelectric to ferroelectric state at around 460 K has been observed to be in good agreement with ceramics of closer composition. Dielectric, piezoelectric and pyroelectric measurements on crystal confirm the ferroelectric behaviour of BTNN 16/84.
Song, Meirong; Liu, Yuru; Cui, Shumin; Liu, Long; Yang, Min
2013-10-01
An aluminum foil with a rough surface was first prepared by anodic treatment in a neutral aqueous solution with the help of pitting corrosion of chlorides. First, the hydrophobic Al surface (contact angle around 79°) became superhydrophilic (contact angle smaller than 5°) after the anodizing process. Secondly, the superhydrophilic Al surface became superhydrophobic (contact angle larger than 150°) after being modified by oleic acid. Finally, the icing property of superhydrophilic, untreated, and superhydrophobic Al foils were investigated in a refrigerated cabinet at -12 °C. The mean total times to freeze a water droplet (6 μL) on the three foils were 17 s, 158 s and 1604 s, respectively. Thus, the superhydrophilic surface accelerates the icing process, while the superhydrophobic surface delays the process. The main reason for this transition might mainly result from the difference of the contact area of the water droplet with Al substrate: the increase in contact area with Al substrate will accelerate the heat conduct process, as well as the icing process; the decrease in contact area with Al substrate will delay the heat conduct process, as well as the icing process. Compared to the untreated Al foil, the contact area of the water droplet with the Al substrate was higher on superhydrophilic surface and smaller on the superhydrophobic surface, which led to the difference of the heat transfer time as well as the icing time.
Tang, Zhehong; Chen, Jieyu; Bai, Yulong; Zhao, Shifeng
2016-08-01
Lead-free magnetoelectric composite films combining Bi4Ti3O12 and CoFe2O4 were synthesized by chemical solution deposition on Pt (100)/Ti/SiO2/Si substrate. Morphological and electrical domain structure, ferroelectric, leakage, dielectric, piezoelectric, magnetic and magnetoelectric properties were investigated for Bi4Ti3O12/CoFe2O4 composite films. Well-defined interfaces between Bi4Ti3O12 and CoFe2O4 film layers and electrical domain structure were observed. The composite films show the coexistence of ferroelectric and ferromagnetic orders at room temperature. Larger piezoelectric coefficient and magnetization are obtained for the composite films, which is contributed to the magnetoelectric effect since it originates from the interface coupling through mechanical strain transfer. This work presents a feasible way to modulate the magnetoelectric coupling in ferromagnetic/ferroelectric composite films for developing lead-free micro-electro-mechanical system and information storage devices.
International Nuclear Information System (INIS)
A new adsorbent (PGCP-COOH) having carboxylate functional group at the chain end was synthesized by grafting poly(hydroxyethylmethacrylate) onto coconut coir pith, CP (a coir industry-based lignocellulosic residue), using potassium peroxydisulphate as an initiator and in the presence of N,N'-methylenebisacrylamide as a cross-linking agent. The adsorbent was characterized with the help of infrared spectroscopy, powder X-ray diffraction, scanning electron microscopy, and potentiometric titrations. The ability of PGCP-COOH to remove Hg(II) from aqueous solutions was assessed using batch adsorption technique under kinetic and equilibrium conditions. Adsorbent exhibits very high adsorption potential for Hg(II) and more than 99.0% removal was achieved in the pH range 5.5-8.0. Adsorption process was found to follow first-order-reversible kinetics. An increase of ionic strength of the medium caused a decrease in metal removal, indicating the occurrence of outer-sphere surface complex mechanism. The equilibrium data were fitted well by the Freundlich isotherm model (R2 = 0.99; χ2 1.81). The removal efficiency was tested using chlor-alkali industry wastewater. Adsorption isotherm experiments were also conducted for comparison using a commercial carboxylate-functionalized ion exchanger, Ceralite IRC-50. Regeneration experiments were tried for four cycles and results indicate a capacity loss of <9.0%
International Nuclear Information System (INIS)
A method is described for the determination of uranium ores, siliceous materials, and solutions. As the matrices of all these materials can vary considerably, a modified background-ratio technique that uses an empirically determined exponent is used to correct for matrix effects, and yields linear calibration curves for U3O8 in briquette form of up to 1000 p.p.m. A background reading taken at 35,0 degrees 2 theta was found to be less subject to interference than the background at 36,70 degrees 2 theta. The relative standard deviation for the method ranges from 0,03 to 0,04 for concentrations of U3O8 from 400 to 4000 p.p.m. Differences between determined and accepted values for reference samples were found to be less than 1% over this range of concentrations. The calculation and evaluation of empirical exponents and the listing of a computer programme are given in the Appendices
Directory of Open Access Journals (Sweden)
Abu Bakar Mohamad
2013-06-01
Full Text Available 1,5-Dimethyl-4-((2-methylbenzylideneamino-2-phenyl-1H-pyrazol-3(2H-one (DMPO was synthesized to be evaluated as a corrosion inhibitor. The corrosion inhibitory effects of DMPO on mild steel in 1.0 M HCl were investigated using electrochemical impedance spectroscopy (EIS, potentiodynamic polarization, open circuit potential (OCP and electrochemical frequency modulation (EFM. The results showed that DMPO inhibited mild steel corrosion in acid solution and indicated that the inhibition efficiency increased with increasing inhibitor concentration. Changes in the impedance parameters suggested an adsorption of DMPO onto the mild steel surface, leading to the formation of protective films. The novel synthesized corrosion inhibitor was characterized using UV-Vis, FT-IR and NMR spectral analyses. Electronic properties such as highest occupied molecular orbital energy, lowest unoccupied molecular orbital energy (EHOMO and ELUMO, respectively and dipole moment (μ were calculated and discussed. The results showed that the corrosion inhibition efficiency increased with an increase in the EHOMO values but with a decrease in the ELUMO value.
Energy Technology Data Exchange (ETDEWEB)
Vallet, Ana, E-mail: avallet@quim.ucm.es [Grupo de Catalisis y Procesos de Separacion (CyPS), Departamento de Ingenieria Quimica, Facultad de Ciencias Quimicas, Universidad Complutense de Madrid, Avda. Complutense s/n, 28040 Madrid (Spain); Besson, Michele, E-mail: michele.besson@ircelyon.univ-lyon1.fr [IRCELYON, Institut de recherches sur la catalyse et l' environnement de Lyon, UMR5256 CNRS-Universite Lyon1, 2 Avenue Albert Einstein, F-69626 Villeurbanne Cedex (France); Ovejero, Gabriel; Garcia, Juan [Grupo de Catalisis y Procesos de Separacion (CyPS), Departamento de Ingenieria Quimica, Facultad de Ciencias Quimicas, Universidad Complutense de Madrid, Avda. Complutense s/n, 28040 Madrid (Spain)
2012-08-15
Highlights: Black-Right-Pointing-Pointer Ni supported over hydrotalcite calcined precursors as catalyst. Black-Right-Pointing-Pointer Catalytic wet air oxidation in trickle bed reactor for Basic Yellow 11 removal. Black-Right-Pointing-Pointer Dye removal depends on temperature, initial dye concentration and flow rate. Black-Right-Pointing-Pointer The catalyst proved to be stable and efficient for the dye degradation. - Abstract: Catalytic wet air oxidation (CWAO) of a Basic Yellow 11 (BY11) aqueous solution, chosen as a model of a hardly biodegradable non-azo dye was carried out in a continuous-flow trickle-bed reactor, using nickel supported over hydrotalcite precursor calcined at 550 Degree-Sign C. An increase in the reaction temperature (120-180 Degree-Sign C), and a decrease in dye concentration (1000-3000 ppm) or liquid flow rate (0.1-0.7 mL min{sup -1}) enhanced the CWAO performance in a 30 and 19% for the variation of the temperature and concentration respectively. After a small leaching observed within the first hours, the catalyst proved to be very stable during the 65-day reaction. The CWAO process was found to be very efficient, achieving BY11 conversion up to 95% and TOC conversion up to 85% at 0.1 mL min{sup -1} and 180 Degree-Sign C under 5 MPa air.
International Nuclear Information System (INIS)
Highlights: ► Ni supported over hydrotalcite calcined precursors as catalyst. ► Catalytic wet air oxidation in trickle bed reactor for Basic Yellow 11 removal. ► Dye removal depends on temperature, initial dye concentration and flow rate. ► The catalyst proved to be stable and efficient for the dye degradation. - Abstract: Catalytic wet air oxidation (CWAO) of a Basic Yellow 11 (BY11) aqueous solution, chosen as a model of a hardly biodegradable non-azo dye was carried out in a continuous-flow trickle-bed reactor, using nickel supported over hydrotalcite precursor calcined at 550 °C. An increase in the reaction temperature (120–180 °C), and a decrease in dye concentration (1000–3000 ppm) or liquid flow rate (0.1–0.7 mL min−1) enhanced the CWAO performance in a 30 and 19% for the variation of the temperature and concentration respectively. After a small leaching observed within the first hours, the catalyst proved to be very stable during the 65-day reaction. The CWAO process was found to be very efficient, achieving BY11 conversion up to 95% and TOC conversion up to 85% at 0.1 mL min−1 and 180 °C under 5 MPa air.
Numerical Asymptotic Solutions Of Differential Equations
Thurston, Gaylen A.
1992-01-01
Numerical algorithms derived and compared with classical analytical methods. In method, expansions replaced with integrals evaluated numerically. Resulting numerical solutions retain linear independence, main advantage of asymptotic solutions.
Directory of Open Access Journals (Sweden)
Carlos Z. Gómez-Castro
2014-09-01
Full Text Available Intramolecular hydrogen bond (HB formation was analyzed in the model compounds N-(2-benzoylphenylacetamide, N-(2-benzoylphenyloxalamate and N1,N2-bis(2-benzoylphenyloxalamide. The formation of three-center hydrogen bonds in oxalyl derivatives was demonstrated in the solid state by the X-ray diffraction analysis of the geometric parameters associated with the molecular structures. The solvent effect on the chemical shift of H6 [δH6(DMSO-d6–δH6(CDCl3] and Δδ(ΝΗ/ΔT measurements, in DMSO-d6 as solvent, have been used to establish the energetics associated with intramolecular hydrogen bonding. Two center intramolecular HB is not allowed in N-(2-benzoylphenylacetamide either in the solid state or in DMSO-d6 solution because of the unfavorable steric effects of the o-benzoyl group. The estimated ΔHº and ΔSº values for the hydrogen bonding disruption by DMSO-d6 of 28.3(0.1 kJ·mol−1 and 69.1(0.4 J·mol−1·K−1 for oxalamide, are in agreement with intramolecular three-center hydrogen bonding in solution. In the solid, the benzoyl group contributes to develop 1-D and 2-D crystal networks, through C–H∙∙∙A (A = O, π and dipolar C=O∙∙∙A (A = CO, π interactions, in oxalyl derivatives. To the best of our knowledge, this is the first example where three-center hydrogen bond is claimed to overcome steric constraints.
PbZr0.4Ti0.6O3 and Ba0.9Sr0.1TiO3 reflectors derived from chemical solutions containing polymers.
Hu, G J; Shang, J L; Sun, Y; Zhang, T; Wu, J; Xie, J
2008-09-15
Ba(0.9)Sr(0.1)TiO3 (BST)-based and PbZr(0.4)Ti(0.6)O(3)-based quasi-periodic multilayers consisting of dense and porous ferroelectric layers have been fabricated by solgel technique using chemical solutions containing polyethylene glycol (PEG) or polyvinylpyrrolidone k30 (PVP). All multilayers exhibit good performance as dielectric mirrors. For each multilayer, the maximum peak reflectivity is over 90% and the photonic stopband width is no less than 30 nm at room temperature. The reflection-band position can be easily tuned by varying the thickness of the bilayer. With the same processing conditions and number of periods, the Bragg reflection performance is almost the same for quasi-periodic PZT multilayers derived from two precursors containing different polymers. The BST multilayers deposited by using a PVP-containing precursor are superior in optical properties, including peak reflectivities and stop-band width, to those deposited by using the PEG-containing solution. PMID:18794931
Cooley, Richard L.
1992-01-01
MODFE, a modular finite-element model for simulating steady- or unsteady-state, area1 or axisymmetric flow of ground water in a heterogeneous anisotropic aquifer is documented in a three-part series of reports. In this report, part 2, the finite-element equations are derived by minimizing a functional of the difference between the true and approximate hydraulic head, which produces equations that are equivalent to those obtained by either classical variational or Galerkin techniques. Spatial finite elements are triangular with linear basis functions, and temporal finite elements are one dimensional with linear basis functions. Physical processes that can be represented by the model include (1) confined flow, unconfined flow (using the Dupuit approximation), or a combination of both; (2) leakage through either rigid or elastic confining units; (3) specified recharge or discharge at points, along lines, or areally; (4) flow across specified-flow, specified-head, or head-dependent boundaries; (5) decrease of aquifer thickness to zero under extreme water-table decline and increase of aquifer thickness from zero as the water table rises; and (6) head-dependent fluxes from springs, drainage wells, leakage across riverbeds or confining units combined with aquifer dewatering, and evapotranspiration. The matrix equations produced by the finite-element method are solved by the direct symmetric-Doolittle method or the iterative modified incomplete-Cholesky conjugate-gradient method. The direct method can be efficient for small- to medium-sized problems (less than about 500 nodes), and the iterative method is generally more efficient for larger-sized problems. Comparison of finite-element solutions with analytical solutions for five example problems demonstrates that the finite-element model can yield accurate solutions to ground-water flow problems.
Energy Technology Data Exchange (ETDEWEB)
Queraltó, A.; Pérez del Pino, A., E-mail: aperez@icmab.es; Mata, M. de la; Tristany, M.; Gómez, A.; Obradors, X.; Puig, T. [Institut de Ciència de Materials de Barcelona, Consejo Superior de Investigaciones Científicas (ICMAB-CSIC), Campus UAB, 08193 Bellaterra, Catalonia (Spain); Arbiol, J. [Institut de Ciència de Materials de Barcelona, Consejo Superior de Investigaciones Científicas (ICMAB-CSIC), Campus UAB, 08193 Bellaterra, Catalonia (Spain); Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluís Companys, 23, 08010 Barcelona, Catalonia (Spain)
2015-06-29
Highly crystalline epitaxial Ba{sub 0.8}Sr{sub 0.2}TiO{sub 3} (BST) thin-films are grown on (001)-oriented LaNiO{sub 3}-buffered LaAlO{sub 3} substrates by pulsed laser irradiation of solution derived barium-zirconium-titanium precursor layers using a UV Nd:YAG laser source at atmospheric conditions. The structural analyses of the obtained films, studied by X-ray diffractometry and transmission electron microscopy, demonstrate that laser processing allows the growth of tens of nm-thick BST epitaxial films with crystalline structure similar to that of films obtained through conventional thermal annealing methods. However, the fast pulsed nature of the laser employed leads to crystallization kinetic evolution orders of magnitude faster than in thermal treatments. The combination of specific photothermal and photochemical mechanisms is the main responsible for the ultrafast epitaxial laser-induced crystallization. Piezoresponse microscopy measurements demonstrate equivalent ferroelectric behavior in laser and thermally annealed films, being the piezoelectric constant ∼25 pm V{sup −1}.
Peter Carr; Roger Lee
2009-01-01
Volatility derivatives are a class of derivative securities where the payoff explicitly depends on some measure of the volatility of an underlying asset. Prominent examples of these derivatives include variance swaps and VIX futures and options. We provide an overview of the current market for these derivatives. We also survey the early literature on the subject. Finally, we provide relatively simple proofs of some fundamental results related to variance swaps and volatility swaps.
DEFF Research Database (Denmark)
Wigan, Duncan
2013-01-01
Contemporary derivatives mark the development of capital and constitute a novel form of ownership. By reconﬁguring the temporal, spatial and legal character of ownership derivatives present a substantive challenge to the tax collecting state. While ﬁscal systems are nationally bounded and inheren...
Simon Gray and Joanna Place
2006-01-01
Derivatives, ranging from relatively simple forward contracts to complicated options products, are an increasingly important feature of financial markets worldwide. They are already being used in many emerging markets, and as the financial sector becomes deeper and more stable, their use is certain to grow. This Handbook provides a basic guide to the different types of derivatives traded, including the pricing and valuation of the products, and accounting and statistical treatment. Also, it a...
Conduction heat transfer solutions
International Nuclear Information System (INIS)
This text is a collection of solutions to a variety of heat conduction problems found in numerous publications, such as textbooks, handbooks, journals, reports, etc. Its purpose is to assemble these solutions into one source that can facilitate the search for a particular problem solution. Generally, it is intended to be a handbook on the subject of heat conduction. This material is useful for engineers, scientists, technologists, and designers of all disciplines, particularly those who design thermal systems or estimate temperatures and heat transfer rates in structures. More than 500 problem solutions and relevant data are tabulated for easy retrieval. There are twelve sections of solutions which correspond with the class of problems found in each. Geometry, state, boundary conditions, and other categories are used to classify the problems. A case number is assigned to each problem for cross-referencing, and also for future reference. Each problem is concisely described by geometry and condition statements, and many times a descriptive sketch is also included. At least one source reference is given so that the user can review the methods used to derive the solutions. Problem solutions are given in the form of equations, graphs, and tables of data, all of which are also identified by problem case numbers and source references
International Nuclear Information System (INIS)
Reviewed in this statement are methods of preparing solutions to be used in laboratory experiments to examine technical issues related to the safe disposal of nuclear waste from power generation. Each approach currently used to prepare solutions has advantages and any one approach may be preferred over the others in particular situations, depending upon the goals of the experimental program. These advantages are highlighted herein for three approaches to solution preparation that are currently used most in studies of nuclear waste disposal. Discussion of the disadvantages of each approach is presented to help a user select a preparation method for his particular studies. Also presented in this statement are general observations regarding solution preparation. These observations are used as examples of the types of concerns that need to be addressed regarding solution preparation. As shown by these examples, prior to experimentation or chemical analyses, laboratory techniques based on scientific knowledge of solutions can be applied to solutions, often resulting in great improvement in the usefulness of results
Aïd, René
2015-01-01
Offering a concise but complete survey of the common features of the microstructure of electricity markets, this book describes the state of the art in the different proposed electricity price models for pricing derivatives and in the numerical methods used to price and hedge the most prominent derivatives in electricity markets, namely power plants and swings. The mathematical content of the book has intentionally been made light in order to concentrate on the main subject matter, avoiding fastidious computations. Wherever possible, the models are illustrated by diagrams. The book should allow prospective researchers in the field of electricity derivatives to focus on the actual difficulties associated with the subject. It should also offer a brief but exhaustive overview of the latest techniques used by financial engineers in energy utilities and energy trading desks.
Numerical Solutions of Fractional Boussinesq Equation
Institute of Scientific and Technical Information of China (English)
WANG Qi
2007-01-01
Based upon the Adomian decomposition method,a scheme is developed to obtain numerical solutions of a fractional Boussinesq equation with initial condition,which is introduced by replacing some order time and space derivatives by fractional derivatives.The fractional derivatives are described in the Caputo sense.So the traditional Adomian decomposition method for differential equations of integer order is directly extended to derive explicit and numerical solutions of the fractional differential equations.The solutions of our model equation are calculated in the form of convergent series with easily computable components.
Energy Technology Data Exchange (ETDEWEB)
Vagner, G.R.; Garaev, A.S.; Guzenko, L.P.; Khaber, N.V.; Kruglitskii, N.N.; Kurochkin, B.M.; Shumilov, V.A.
1981-03-23
Proposed is a plugging solution which contains cement, hydrophilic biosilica, polymer, and water, and which is distinguished by the fact that in order to increase the strength properties of the stone with simultaneous increase in its resistance to the effect of corrosive bed water under conditions of normal temperatures, as hydrophilic biosilica the solution contains carboxy aerosil or aminoethoxy aerosil, and as a polymer, carboxylate divinyl styrene latex and it also contains sodium with the following ingredient ratio, wt %: 63.47-66.08% cement, 0.66-1.28% carboxylate divinyl styrene latex, 1.26-1.32% sodium chloride, 0.22-0.36% carboxy aerosil or aminoethoxy aerosil, and the rest water. The plugging solution is distinguished by the fact that carboxy aerosil or aminoethoxy aerosil have a specific surface of 50-300 m/g.
Energy Technology Data Exchange (ETDEWEB)
Sharipov, A.U.; Polyakov, V.N.; Yangirova, I.Z.
1982-06-10
Proposed is a plugging solution containing cement, modified methyl cellulose, and water. In order to decrease the viscosity in time with the preservation of filtration and strength properties of the solution and stone, it also contains wastes of the production of 4,4-dimethyl dioxane-1,3 with following ratio of components, mass%: 66.0-67.0% cement; 0.07-0.15 modified methyl cellulose, 0.13-0.33% wastes from the production of 4,4-dimethyl dioxane-1,3, and the rest water.
Strong solutions for the Levi curvature equation
Citti, G.; Montanari, A.
2000-01-01
We consider the prescribed Levi curvature equation, a second order quasilinear equation whose associated operator can be represented as a sum of squares of nonlinear vector fields. For this equation we introduce a notion of derivatives modeled on the geometry of the associated operator and prove an a priori $L^2$ estimate for these second order intrinsic derivatives of a viscosity solution. We then show that viscosity solutions are strong solutions in a natural sense and satisf...
Hyperscaling Violating Solutions in Generalised EMD Theory
Li, Li
2016-01-01
This short note is devoted to deriving scaling but hyperscaling violating solutions in a generalised Einstein-Maxwell-Dilaton theory with an arbitrary number of scalars and vectors. We obtain analytic solutions in some special case and discuss the physical constraints on the allowed parameter range in order to have a well-defined holographic ground-state solution.
Directory of Open Access Journals (Sweden)
Reza A Zoroofi
2007-08-01
Full Text Available Medal Electronic (ME Engineering Company provides high quality systems, software and services in medical image management, processing and visualization. We assist health care professionals to improve and extend the efficiency of their practices with cost effective solutions. ME is the developer of several medical software including MEDAL-PACS, 3D-Sonosoft, Analytical-Electrophoresis, CBONE and Rhino-Plus. ME is also the exclusive distributor of PACSPLUS in Iran. PACSPLUS is an international, standard, scalable and enterprise PACS solution. PACSPLUS is of ISO, CE and FDA-510 approvals. It is now operational in more than 1000 clinical environment throughout the globe. We discuss about the key features of PACSPLUS system for dealing with real world challenge in PACS as well as the PACS solu-tions needed to fulfill the demands of the clinicians in Iran. Our experience in developing high-end medical software confirms our capability in providing the PACSPLUS as an ultimate PACS solution in Iran.
Geoghegan, Michael W
2005-01-01
Podcasting is the art of recording radio show style audio tracks, then distributing them to listeners on the Web via podcasting software such as iPodder. From downloading podcasts to producing a track for fun or profit, ""Podcast Solutions"" covers the entire world of podcasting with insight, humor, and the unmatched wisdom of experience.
Semianalytic Solution of Space-Time Fractional Diffusion Equation
Directory of Open Access Journals (Sweden)
A. Elsaid
2016-01-01
Full Text Available We study the space-time fractional diffusion equation with spatial Riesz-Feller fractional derivative and Caputo fractional time derivative. The continuation of the solution of this fractional equation to the solution of the corresponding integer order equation is proved. The series solution of this problem is obtained via the optimal homotopy analysis method (OHAM. Numerical simulations are presented to validate the method and to show the effect of changing the fractional derivative parameters on the solution behavior.
Hill, Colin
2010-01-01
Recently we reported a role for compatible solute uptake in mediating bile tolerance and increased gastrointestinal persistence in the foodborne pathogen Listeria monocytogenes.1 Herein, we review the evolution in our understanding of how these low molecular weight molecules contribute to growth and survival of the pathogen both inside and outside the body, and how this stress survival mechanism may ultimately be used to target and kill the pathogen. PMID:21326913
Chemistry of ruthenium in nitric acid solution with special regard to nuclear fuel solutions
International Nuclear Information System (INIS)
A review is given concerning the published knowledge about the chemistry of ruthenium in nitric acid solution with special reference to nitric acid nuclear fuel solutions. Possibilities of the spectroscopic description of the different existing ruthenium complexes are discussed and papers are presented dealing with the estimation of the proportions of the different ruthenium compounds in nuclear fuel solutions. Finally, arguments are derived for the preparation of ruthenium-containing model solutions, which adequately simulate the composition of real nuclear fuel solutions. (author)
Institute of Scientific and Technical Information of China (English)
默会霞; 余东艳; 隋鑫
2014-01-01
Nonlinear Schr¨odinger equation is a general nonlinear model in modern science. Using the Ado-main decomposition method, we construct the approximate solutions to the (2+1) and (3+1) dimensional time fractional Sch¨ordinger equations with nonzero trapping potential. It is not necessary for us to decompose the solution function into real part and imaginary part as in relative references. So, the Adomain decomposition simplifies the procedure of solving the equation.%非线性薛定谔方程是现代科学中非常普遍的非线性模型之一。通过 Adomain分解，得到了(2+1)维和(3+1)维非零势阱时间分数阶薛定谔方程的近似解。利用Adomain 分解不用像相关文献中那样将解函数的实部和虚部分别去求解，从而简化了求解过程。
Functionalized polymers for binding to solutes in aqueous solutions
Smith, Barbara F.; Robison, Thomas W.
2006-11-21
A functionalized polymer for binding a dissolved molecule in an aqueous solution is presented. The polymer has a backbone polymer to which one or more functional groups are covalently linked. The backbone polymer can be such polymers as polyethylenimine, polyvinylamine, polyallylamine, and polypropylamine. These polymers are generally water-soluble, but can be insoluble when cross-linked. The functional group can be for example diol derivatives, polyol derivatives, thiol and dithiol derivatives, guest-host groups, affinity groups, beta-diphosphonic acids, and beta-diamides
DEFF Research Database (Denmark)
Efeoglu, Arkin; Møller, Charles; Serie, Michel
2013-01-01
environment. The solution prototype that is composed from blending product and service prototype has particular impacts on the dualism of DSR’s “Build” and “Evaluate”. Since the mix between product and service prototyping can be varied, there is a demand for a more agile and iterative framework. Van de Ven......’s research framework seems to fit this purpose. Van de Ven allows for an iterative research approach to problem solving with flexible starting point. The research activity is the result between the iteration of two dimensions. This framework focuses on the natural evaluation, particularly on ex...
2012-01-01
Multilingual Solutions ofrecera capacitación a los agentes de Contact y Call centers de Bogotá con dominio de una segunda lengua. La capacitación consiste en mejorar las falencias comunicativas que se presentan en empresas de este tipo, y así optimizar los servicios de estas compañías por medio de mejoras en el servicio prestado por sus agentes; siendo estas las características que la hacen diferente de las demás empresas prestadoras de servicios de capacitación. Con base a los estudios reali...
Chun, Tiejun; Zhu, Deqing; Pan, Jian; He, Zhen
2014-06-01
Recovery of alumina from magnetic separation tailings of red mud has been investigated by Na2CO3 solution leaching. X-ray diffraction (XRD) results show that most of the alumina is present as 12CaO·7Al2O3 and CaO·Al2O3 in the magnetic separation tailings. The shrinking core model was employed to describe the leaching kinetics. The results show that the calculated activation energy of 8.31 kJ/mol is characteristic for an internal diffusion-controlled process. The kinetic equation can be used to describe the leaching process. The effects of Na2CO3 concentration, liquid-to-solid ratio, and particle size on recovery of Al2O3 were examined.
Energy Technology Data Exchange (ETDEWEB)
Gacem, Lakhdar [ICMCB-CNRS, Universite de Bordeaux, 87 av. Schweitzer, 33608 Pessac (France); Departement de physique, Universite Mohamed Khider de Biskra, Biskra 07000 (Algeria); Ouadjaout, Djamel [UDTS, 2 Bd. Frantz Fanon, BP. 140 Alger-7 Merveilles, 16200 Alger (Algeria); Chaminade, Jean-Pierre, E-mail: chamin@icmcb-bordeaux.cnrs.fr [ICMCB-CNRS, Universite de Bordeaux, 87 av. Schweitzer, 33608 Pessac (France); Maglione, Mario; Von der Muehll, Regnault; Pechev, Stanislas [ICMCB-CNRS, Universite de Bordeaux, 87 av. Schweitzer, 33608 Pessac (France)
2009-12-15
Single crystals of (1 - x)BaTiO{sub 3} + xNaNbO{sub 3} (BTNN) for x = 0.84 were obtained by high temperature solution growth using Na{sub 2}B{sub 4}O{sub 7} as solvent. The room temperature crystal structure of BTNN 16/84-phase was determined from X-ray single crystal diffraction data, in the tetragonal system with space group P4bm. The refinement from 246 independent reflections led to the following parameters: a = b = 5.5845(3) A, c = 3.9453(2) A, V = 123.041(11) A{sup 3}, Z = 2, with final cR{sub wp} = 0.150 and R{sub B} = 0.041. The structure of BTNN 16/84-phase can be described as a three-dimensional framework built up from (Nb-Ti)O{sub 6} octahedra with Na and Ba in the dodecahedral site of perovskite-like type. Some mm{sup 3}-sized crystals have been selected and various dielectric measurements (ferroelectric, pyroelectric, and piezoelectric) have been performed. Transition from paraelectric to ferroelectric state at around 460 K has been observed to be in good agreement with ceramics of closer composition. Dielectric, piezoelectric and pyroelectric measurements on crystal confirm the ferroelectric behaviour of BTNN 16/84.
Directory of Open Access Journals (Sweden)
Mohammad Hossein Sattari
2016-06-01
Full Text Available In this article, the notion of $n-$derivation is introduced for all integers $ngeq 2$. Although all derivations are $n-$derivations, in general these notions are not equivalent. Some properties of ordinary derivations are investigated for $n-$derivations. Also, we show that under certain mild condition $n-$derivations are derivations.
Equivalence of Network-Solution and PPP-Solution
Institute of Scientific and Technical Information of China (English)
PENG Lin; LIU Yanxiong; ZHOU Xinghua; WU Yongting
2006-01-01
The technique of precise point positioning (PPP) is gradually becoming a popular method in GPS data-processing. In GPS observation equation, the unknown parameters can be separated into two parts: global parameters and local parameters. The global parameters include orbit, satellite clock and geodynamic parameters. The local parameters are site-occupation-specific, such as position, tropospheric delay, etc. The formulas of local parameters are firstly derived under the network-solution and the PPP-solution conditions respectively. If the weight matrix of global parameters in PPP-solution is small enough, the cofactor matrices of local parameters are the same as that in network-solution. Then, 16 daily solutions are obtained in both PPP mode and network mode. Three sites are selected to compare the solutions. The experimental results demonstrated that the difference between two solutions in coordinates and tropospheric delays are only few millimeters. This level of difference can be neglected so that the solutions from both PPP mode and network mode can be taken as the same in the actual application.
Morris, Simon Conway
2004-11-01
Life's Solution builds a persuasive case for the predictability of evolutionary outcomes. The case rests on a remarkable compilation of examples of convergent evolution, in which two or more lineages have independently evolved similar structures and functions. The examples range from the aerodynamics of hovering moths and hummingbirds to the use of silk by spiders and some insects to capture prey. Going against the grain of Darwinian orthodoxy, this book is a must read for anyone grappling with the meaning of evolution and our place in the Universe. Simon Conway Morris is the Ad Hominen Professor in the Earth Science Department at the University of Cambridge and a Fellow of St. John's College and the Royal Society. His research focuses on the study of constraints on evolution, and the historical processes that lead to the emergence of complexity, especially with respect to the construction of the major animal body parts in the Cambrian explosion. Previous books include The Crucible of Creation (Getty Center for Education in the Arts, 1999) and co-author of Solnhofen (Cambridge, 1990). Hb ISBN (2003) 0-521-82704-3
Exact Axially Symmetric Solution in f(T) Gravity Theory
2014-01-01
A general tetrad field with sixteen unknown functions is applied to the field equations of f(T) gravity theory. An analytic vacuum solution is derived with two constants of integration and an angle Φ that depends on the angle coordinate ϕ and radial coordinate r . The tetrad field of this solution is axially symmetric and the scalar torsion vanishes. We calculate the associated metric of the derived solution and show that it represents Kerr spacetime. Finally, we show that the derived solutio...
On Alternative Optimal Solutions to Linear Fractional Optimization Problems
Institute of Scientific and Technical Information of China (English)
ShengjiaXue
2004-01-01
The structure of the optimal solution set is derived for linear fractional optimization problems with the representation theorem of polyhedral sets．And the computational procedure in determining all optimal solutions is also given．
Organometallic derivatives of sydnone imines
International Nuclear Information System (INIS)
By the method of direct metallation of 3-cyclohexyl-N6-pivaloylsydnone imine by butyllithium solution in tetrahydrofuran at -78 deg C for 30 min. 4-lithium derivative of the relevant sydnone imine (1) was prepared. Compound 1 was characterized by the methods of elementary analysis, 1H NMR and IR spectroscopy. It is shown that the compound prepared features extremely low nucleophilic properties and in terms of its chemical behavior it reminds lithium sydnones. Replacement of substituents in position 3 of the heterocycle and at exocyclic nitrogen atom affects but slightly the metallation process of sydnone imines and stability of lithium derivatives
Traveling Wave Solutions in a Reaction-Diffusion Epidemic Model
Sheng Wang; Wenbin Liu; Zhengguang Guo; Weiming Wang
2013-01-01
We investigate the traveling wave solutions in a reaction-diffusion epidemic model. The existence of the wave solutions is derived through monotone iteration of a pair of classical upper and lower solutions. The traveling wave solutions are shown to be unique and strictly monotonic. Furthermore, we determine the critical minimal wave speed.
Strongly nonlinear oscillators analytical solutions
Cveticanin, Livija
2014-01-01
This book provides the presentation of the motion of pure nonlinear oscillatory systems and various solution procedures which give the approximate solutions of the strong nonlinear oscillator equations. The book presents the original author’s method for the analytical solution procedure of the pure nonlinear oscillator system. After an introduction, the physical explanation of the pure nonlinearity and of the pure nonlinear oscillator is given. The analytical solution for free and forced vibrations of the one-degree-of-freedom strong nonlinear system with constant and time variable parameter is considered. Special attention is given to the one and two mass oscillatory systems with two-degrees-of-freedom. The criteria for the deterministic chaos in ideal and non-ideal pure nonlinear oscillators are derived analytically. The method for suppressing chaos is developed. Important problems are discussed in didactic exercises. The book is self-consistent and suitable as a textbook for students and also for profess...
Exact cosmological solutions for MOG
Energy Technology Data Exchange (ETDEWEB)
Roshan, Mahmood [Ferdowsi University of Mashhad, Department of Physics, P.O. Box 1436, Mashhad (Iran, Islamic Republic of)
2015-09-15
We find some new exact cosmological solutions for the covariant scalar-tensor-vector gravity theory, the so-called modified gravity (MOG). The exact solution of the vacuum field equations has been derived. Also, for non-vacuum cases we have found some exact solutions with the aid of the Noether symmetry approach. More specifically, the symmetry vector and also the Noether conserved quantity associated to the point-like Lagrangian of the theory have been found. Also we find the exact form of the generic vector field potential of this theory by considering the behavior of the relevant point-like Lagrangian under the infinitesimal generator of the Noether symmetry. Finally, we discuss the cosmological implications of the solutions. (orig.)
Twisting singular solutions of Bethe's equations
Nepomechie, Rafael I
2014-01-01
The Bethe equations for the periodic XXX and XXZ spin chains admit singular solutions, for which the corresponding eigenvalues and eigenvectors are ill-defined. We use a twist regularization to derive conditions for such singular solutions to be physical, in which case they correspond to genuine eigenvalues and eigenvectors of the Hamiltonian.
Analytical Solutions for Sequentially Reactive Transport with Different Retardation Factors
Energy Technology Data Exchange (ETDEWEB)
Sun, Y; Buscheck, T A; Mansoor, K; Lu, X
2001-08-01
Integral transforms have been widely used for deriving analytical solutions for solute transport systems. Often, analytical solutions can only be written in closed form in frequency domains and numerical inverse-transforms have to be involved to obtain semi-analytical solutions in the time domain. For this reason, previously published closed form solutions are restricted either to a small number of species or to the same retardation assumption. In this paper, we applied the solution scheme proposed by Bauer et al. in the time domain. Using available analytical solutions of a single species transport with first-order decay without coupling with its parent species concentration as fundamental solutions, a daughter species concentration can be expressed as a linear function of those fundamental solutions. The implementation of the solution scheme is straight forward and exact analytical solutions are derived for one- and three-dimensional transport systems.
Scaling solutions for Dilaton Quantum Gravity
Henz, Tobias; Pawlowski, Jan Martin; Wetterich, Christof
2016-01-01
Scaling solutions for the effective action in dilaton quantum gravity are investigated within the functional renormalization group approach. We find numerical solutions that connect ultraviolet and infrared fixed points as the ratio between scalar field and renormalization scale $k$ is varied. In the Einstein frame the quantum effective action corresponding to the scaling solutions becomes independent of $k$. The field equations derived from this effective action can be used directly for cosm...
Robinson-Trautman solution with scalar hair
Tahamtan, T
2015-01-01
Explicit Robinson-Trautman solution with minimally coupled free scalar field is derived and analyzed. It is shown that this solution contains curvature singularity which is initially naked but later the horizon envelopes it. We use quasilocal horizon definition and prove its existence in later retarded times using sub- and supersolution method combined with growth estimates. We show that the solution is generally of algebraic type II but reduces to type D in spherical symmetry.
Exact solution of phantom dark energy model
Institute of Scientific and Technical Information of China (English)
Wang Wen-Fu; Shui Zheng-Wei; Tang Bin
2010-01-01
We investigate the phantom dark energy model derived from the scalar field with a negative kinetic term. By assuming a particular relation between the time derivative of the phantom field and the Hubble function, an exact solution of the model is constructed. Absence of the 'big rip' singularity is shown explicitly. We then derive special features of phantom dark energy model and show that its predictions are consistent with all astrophysical observations.
Value solutions in cooperative games
McCain, Roger A
2013-01-01
This book introduces new concepts for cooperative game theory, and particularly solutions that determine the distribution of a coalitional surplus among the members of the coalition. It also addresses several generalizations of cooperative game theory. Drawing on methods of welfare economics, new value solutions are derived for Non-Transferable Utility games with and without differences of bargaining power among the members of the coalition. Cooperation in intertemporal games is examined, and conditions that permit the reduction of these games to games in coalition function form are outlined.
An Analytical Method of Auxiliary Sources Solution for Plane Wave Scattering by Impedance Cylinders
DEFF Research Database (Denmark)
Larsen, Niels Vesterdal; Breinbjerg, Olav
Analytical Method of Auxiliary Sources solutions for plane wave scattering by circular impedance cylinders are derived by transformation of the exact eigenfunction series solutions employing the Hankel function wave transformation. The analytical Method of Auxiliary Sources solution thus obtained...
Exact solution to fractional logistic equation
West, Bruce J.
2015-07-01
The logistic equation is one of the most familiar nonlinear differential equations in the biological and social sciences. Herein we provide an exact solution to an extension of this equation to incorporate memory through the use of fractional derivatives in time. The solution to the fractional logistic equation (FLE) is obtained using the Carleman embedding technique that allows the nonlinear equation to be replaced by an infinite-order set of linear equations, which we then solve exactly. The formal series expansion for the initial value solution of the FLE is shown to be expressed in terms of a series of weighted Mittag-Leffler functions that reduces to the well known analytic solution in the limit where the fractional index for the derivative approaches unity. The numerical integration to the FLE provides an excellent fit to the analytic solution. We propose this approach as a general technique for solving a class of nonlinear fractional differential equations.
Normal BGG solutions and polynomials
Cap, A; Hammerl, M
2012-01-01
First BGG operators are a large class of overdetermined linear differential operators intrinsically associated to a parabolic geometry on a manifold. The corresponding equations include those controlling infinitesimal automorphisms, higher symmetries, and many other widely studied PDE of geometric origin. The machinery of BGG sequences also singles out a subclass of solutions called normal solutions. These correspond to parallel tractor fields and hence to (certain) holonomy reductions of the canonical normal Cartan connection. Using the normal Cartan connection, we define a special class of local frames for any natural vector bundle associated to a parabolic geometry. We then prove that the coefficient functions of any normal solution of a first BGG operator with respect to such a frame are polynomials in the normal coordinates of the parabolic geometry. A bound on the degree of these polynomials in terms of representation theory data is derived. For geometries locally isomorphic to the homogeneous model of ...
Fractional Diffusion based on Riemann-Liouville Fractional Derivatives
Hilfer, R.
2000-01-01
A fractional diffusion equation based on Riemann-Liouville fractional derivatives is solved exactly. The initial values are given as fractional integrals. The solution is obtained in terms of $H$-functions. It differs from the known solution of fractional diffusion equations based on fractional integrals. The solution of fractional diffusion based on a Riemann-Liouville fractional time derivative does not admit a probabilistic interpretation in contrast with fractional diffusion based on frac...
Scaling solutions for Dilaton Quantum Gravity
Henz, Tobias; Wetterich, Christof
2016-01-01
Scaling solutions for the effective action in dilaton quantum gravity are investigated within the functional renormalization group approach. We find numerical solutions that connect ultraviolet and infrared fixed points as the ratio between scalar field and renormalization scale $k$ is varied. In the Einstein frame the quantum effective action corresponding to the scaling solutions becomes independent of $k$. The field equations derived from this effective action can be used directly for cosmology. Scale symmetry is spontaneously broken by a non-vanishing cosmological value of the scalar field. For the cosmology corresponding to our scaling solutions, inflation arises naturally. The effective cosmological constant becomes dynamical and vanishes asymptotically as time goes to infinity.
2001-01-01
In this note we introduce an egalitarian solution, called the dual egalitarian solution, that is the natural counterpart of the egalitarian solution of Dutta and Ray (1989). We prove, among others, that for a convex game the egalitarian solution coincides with the dual egalitarian solution for its dual concave game.
Klijn, F.; Slikker, M.; Tijs, S.H.
2000-01-01
In this note we introduce an egalitarian solution, called the dual egalitarian solution, that is the natural counterpart of the egalitarian solution of Dutta and Ray (1989).We prove, among others, that for a convex game the egalitarian solution coincides with the dual egalitarian solution for its dual concave game.
Nonequilibrium thermodynamics of pressure solution
Lehner, F. K.; Bataille, J.
1984-01-01
This paper is concerned with the thermodynamic theory of solution and precipitation processes in wet crustal rocks and with the mechanism of steady pressure-solution slip in ‘contact zones,’ such as grain-to-grain contacts, fracture surfaces, and permeable gouge layers, that are infiltrated by a mobile aqueous solution phase. A local dissipation jump condition at the phase boundary is fundamental to identifying the thermodynamic force driving the solution and precipitation process and is used here in setting up linear phenomenological relations to model near-equilibrium phase transformation kinetics. The local thermodynamic equilibrium of a stressed pure solid in contact with its melt or solution phase is governed by Gibbs's relation, which is rederived here, in a manner emphasizing its independence of constitutive assumptions for the solid while neglecting surface tension and diffusion in the solid. Fluid-infiltrated contact zones, such as those formed by rough surfaces, cannot generally be in thermodynamic equilibrium, especially during an ongoing process of pressure-solution slip, and the existing equilibrium formulations are incorrect in overlooking dissipative processes tending to eliminate fluctuations in superficial free energies due to stress concentrations near asperities, defects, or impurities. Steady pressure-solution slip is likely to exhibit a nonlinear dependence of slip rate on shear stress and effective normal stress, due to a dependence of the contact-zone state on the latter. Given that this dependence is negligible within some range, linear relations for pressure-solution slip can be derived for the limiting cases of diffusion-controlled and interface-reaction-controlled rates. A criterion for rate control by one of these mechanisms is set by the magnitude of the dimensionless quantity kδ/2C pD, where k is the interfacial transfer coefficient, δ is the mean diffusion path length, C p is the solubility at pressure p, and D is the mass
Exact vacuum solution of a (1+2)-dimensional Poincare gauge theory BTZ solution with torsion
Garcia, A A; Heinicke, C; Macías, A; Garcia, Alberto A.; Hehl, Friedrich W.; Heinicke, Christian; Macias, Alfredo
2003-01-01
In (1+2)-dimensional Poincar\\'e gauge gravity, we start from a Lagrangian depending on torsion and curvature which includes additionally {\\em translational} and {\\em Lorentzian} Chern-Simons terms. Limiting ourselves to to a specific subcase, the Mielke-Baekler (MB) model, we derive the corresponding field equations (of Einstein-Cartan-Chern-Simons type) and find the general vacuum solution. We determine the properties of this solution, in particular its mass and its angular momentum. For vanishing torsion, we recover the BTZ-solution. We also derive the general conformally flat vacuum solution with torsion. In this framework, we discuss {\\em Cartan's} (3-dimensional) {\\em spiral staircase} and find that it is not only a special case of our new vacuum solution, but can alternatively be understood as a solution of the 3-dimensional Einstein-Cartan theory with matter of constant pressure and constant torque. {\\em file 3dexact15.tex}
Synthesis and Aqueous Solution Viscosity of Hydrophobically Modified Xanthan Gum
Institute of Scientific and Technical Information of China (English)
QIAN Xiao-lin; WU Wen-hui; YU Pei-zhi; WANG Jian-quan
2007-01-01
Two xanthan gum derivatives hydrophobically modified by 4 or 8 tetradecyl chains per 100 xanthan gum structure units were synthesized. The derivatives were studied by scanning electron microscope and pyrene fluorescence spectrometry. And the aqueous solution apparent viscosity of the derivatives was investigated. The results indicate that the network of the derivatives with more hydrophobic groups is closer and tighter. With increasing of alkyl chain substitution degree, the hydrophobically associating interactions enhance in aqueous solution. Aqueous solution apparent viscosity of the derivatives increases with increasing of polymer concentration and alkyl substitution degree, and decreases with the increase of temperature. In the brine solution, the strong viscosity enhancement phenomenon appears. The interaction between the derivatives and surfactant sodium dodecylbenzene sulfonate is strong.
DEFF Research Database (Denmark)
Svenstrup, Mikkel
This Ph.D. thesis consists of four self-contained essays on valuation of interest rate derivatives. In particular derivatives related to management of interest rate risk care are considered.......This Ph.D. thesis consists of four self-contained essays on valuation of interest rate derivatives. In particular derivatives related to management of interest rate risk care are considered....
One-soliton solutions from Laplace’s seed
Indian Academy of Sciences (India)
S Chaudhuri; K C Das
2002-03-01
One-soliton solutions of axially symmetric vacuum Einstein ﬁeld equations are presented in this paper. Two sets of Laplace’s solutions are used as seed and it is shown that the derived solutions reduce to some already known solutions when the constants are properly adjusted. An analysis of the solutions in terms of the Ernst potential is also presented. It is found that the solutions do not reduce to the Euclidean form at spatial inﬁnity. However, in the static limit, Weyl solutions are obtained for half integral -values.
Synthetic Bioluminescent Coelenterazine Derivatives.
Nishihara, Ryo; Citterio, Daniel; Suzuki, Koji
2016-01-01
The development of coelenterazine (CTZ) derivatives resulting in superior optical characteristics is an efficient method to extend the range of its possible applications. Here, we describe the synthesis of three C-6 substituted CTZ derivatives retaining the recognition by Renilla luciferase (RLuc) and its derivatives. The novel derivatives are useful as bright blue-shifted CTZ derivatives, which can be used as an alternative to hitherto reported compound DeepBlueC™. PMID:27424892
Analytic solutions of a class of nonlinearly dynamic systems
Energy Technology Data Exchange (ETDEWEB)
Wang, M-C [System Engineering Institute of Tianjin University, Tianjin, 300072 (China); Zhao, X-S; Liu, X [Tianjin University of Technology and Education, Tianjin, 300222 (China)], E-mail: mchwang123@163.com.cn, E-mail: xszhao@mail.nwpu.edu.cn, E-mail: liuxinhubei@163.com.cn
2008-02-15
In this paper, the homotopy perturbation method (HPM) is applied to solve a coupled system of two nonlinear differential with first-order similar model of Lotka-Volterra and a Bratus equation with a source term. The analytic approximate solutions are derived. Furthermore, the analytic approximate solutions obtained by the HPM with the exact solutions reveals that the present method works efficiently.
Static Solutions of Einstein's Equations with Cylindrical Symmetry
Trendafilova, C. S.; Fulling, S. A.
2011-01-01
In analogy with the standard derivation of the Schwarzschild solution, we find all static, cylindrically symmetric solutions of the Einstein field equations for vacuum. These include not only the well-known cone solution, which is locally flat, but others in which the metric coefficients are powers of the radial coordinate and the spacetime is…
Magneto-micropolar fluid motion: global existence of strong solutions
Directory of Open Access Journals (Sweden)
Elva E. Ortega-Torres
1999-01-01
Full Text Available By using the spectral Galerkin method, we prove a result on global existence in time of strong solutions for the motion of magneto-micropolar fluid without assuming that the external forces decay with time. We also derive uniform in time estimates of the solution that are useful for obtaining error bounds for the approximate solutions.
A Contracted Path Integral Solution of the Discrete Master Equation
Helbing, Dirk
1998-01-01
A new representation of the exact time dependent solution of the discrete master equation is derived. This representation can be considered as contraction of the path integral solution of Haken. It allows the calculation of the probability distribution of the occurence time for each path and is suitable as basis of new computational solution methods.
Fractional Solutions of Bessel Equation with N-Method
Erdal Bas; Resat Yilmazer; Etibar Panakhov
2013-01-01
This paper deals with the design fractional solution of Bessel equation. We obtain explicit solutions of the equation with the help of fractional calculus techniques. Using the N-fractional calculus operator N ν method, we derive the fractional solutions of the equation.
On rotational solutions for elliptically excited pendulum
International Nuclear Information System (INIS)
The author considers the planar rotational motion of the mathematical pendulum with its pivot oscillating both vertically and horizontally, so the trajectory of the pivot is an ellipse close to a circle. The analysis is based on the exact rotational solutions in the case of circular pivot trajectory and zero gravity. The conditions for existence and stability of such solutions are derived. Assuming that the amplitudes of excitations are not small while the pivot trajectory has small ellipticity the approximate solutions are found both for high and small linear dampings. Comparison between approximate and numerical solutions is made for different values of the damping parameter. -- Highlights: → We study rotations of the mathematical pendulum when its pivot moves along an ellipse. → There are stable exact solutions for a circular pivot trajectory and zero gravity. → Asymptotic solutions are found for an elliptical pivot trajectory
Radiation processing of polysaccharide derivatives
International Nuclear Information System (INIS)
Carboxymethylcellulose (CMC), carboxymethylstarch (CMS), carboxymethylchitin (CM-chitin) and carboxymethylchitosan (CM-chitosan) form gels when irradiated at paste-like condition. Bedsore prevention mat filled up CMC hydrogel crosslinked by irradiation at paste-like condition was practical applied as a health care products. It was found that CM-chitosan hydrogels have anti-microbial activity and effective as absorbents to remove metal ions. When crosslinked gel sheets of CM-chitin and CM-chitosan were immersed in copper (II) aqueous solution, absorption of Cu (II) were 161 mg/g and 172 mg/g, respectively. Radiation crosslinking of cellulose derivative such as hydroxypropyl methylcellulose phthalate, (HPMCP) kneaded with aqueous alkali solution and methanol was achieved with EB-irradiation at paste-like condition. The HPMCP gel absorbed organic solvents such as chloroform and pyridine. (author)
Radiological protection optimization using derivatives
International Nuclear Information System (INIS)
The aim of this paper is to provide a different approach related to the integral cost-benefit and extended cost-benefit analysis used in the decision-aiding techniques. In the ICRP publication 55 the annual protection cost is envisaged as a set of points, each of them representing an option, linked by a straight line. The detriment cost function is considered a linear function whose angular coefficient is determined by the alpha value. In this paper the uranium mine example considered in the ICRP publication 55 was used. But the potential curve was introduced both in the integral cost benefit analysis and in the extended cost-benefit analysis, which the individual dose distribution attribute is added. The result was obtained using derivatives. The detriment cost, Y, is not necessary because the alpha value is known. The Y derivative dS/dY is the alpha value itself and so, the attention is directed to the derivative -dX/dS on the points that, along with the alpha value, present the optimum option. The results makes clear that the prevailing factor in the optimum option selection is the alpha value imputed, and those a single alpha value, as suggested now, probably as little efficiency on the optimization process. Obtaining a curve for the alpha value and using the derivative technique introduced in this paper, the analytical solution is more convenient and reliable compared to the one used now. (authors)
Black holes in higher derivative gravity.
Lü, H; Perkins, A; Pope, C N; Stelle, K S
2015-05-01
Extensions of Einstein gravity with higher-order derivative terms arise in string theory and other effective theories, as well as being of interest in their own right. In this Letter we study static black-hole solutions in the example of Einstein gravity with additional quadratic curvature terms. A Lichnerowicz-type theorem simplifies the analysis by establishing that they must have vanishing Ricci scalar curvature. By numerical methods we then demonstrate the existence of further black-hole solutions over and above the Schwarzschild solution. We discuss some of their thermodynamic properties, and show that they obey the first law of thermodynamics. PMID:25978224
Black Holes in Higher-Derivative Gravity
Lu, H; Pope, C N; Stelle, K S
2015-01-01
Extensions of Einstein gravity with higher-order derivative terms arise in string theory and other effective theories, as well as being of interest in their own right. In this paper we study static black-hole solutions in the example of Einstein gravity with additional quadratic curvature terms. A Lichnerowicz-type theorem simplifies the analysis by establishing that they must have vanishing Ricci scalar curvature. By numerical methods we then demonstrate the existence of further black-hole solutions over and above the Schwarzschild solution. We discuss some of their thermodynamic properties, and show that they obey the first law of thermodynamics.
Solutions manual to accompany Fundamentals of calculus
Morris, Carla C
2015-01-01
Solutions Manual to Accompany Fundamentals of Calculus the text that encourages students to use power, quotient, and product rules for solutions as well as stresses the importance of modeling skills. In addition to core integral and differential calculus coverage, the core book features finite calculus, which lends itself to modeling and spreadsheets. Specifically, finite calculus is applied to marginal economic analysis, finance, growth, and decay. Includes: Linear Equations and Functions The Derivative Using the Derivative Exponential and Logarithmic
Spherically symmetric solutions in a FRW background
Moradpour, H.; Riazi, N.
2015-02-01
We impose perfect fluid concept along with slow expansion approximation to derive new solutions which, considering non-static spherically symmetric metrics, can be treated as Black Holes (BHs). We will refer to these solutions as Quasi BHs. Mathematical and physical features such as Killing vectors, singularities, and mass have been studied. Their horizons and thermodynamic properties have also been investigated. In addition, relationship with other related works (including McVittie's) are described.
International Nuclear Information System (INIS)
A radiochromic solution which is sensitive to small dosages of ionizing and ultraviolet radiation is described. It consists of a solution of a leucocyanide dye in a clear polar solvent with enough organic acid added to make the solution at least slightly acidic and responds to radiation by permanently changing color. Up to one half of the solution by weight can be replaced by a second solution of an aromatic solvent and an organic fluor. Another modification of the invention is a solution of a leucocyanide dye in a clear polar solvent having an aromatic group, an organic fluor, and enough organic acid to make the solution at least slightly acidic. (author)
The Asymmetric Leximin Solution
Driesen, Bram W.
2012-01-01
In this article we define and characterize a class of asymmetric leximin solutions, that contains both the symmetric leximin solution of Imai[5] and the two-person asymmetric Kalai-Smorodinsky solution of Dubra [3] as special cases. Solutions in this class combine three attractive features: they are defined on the entire domain of convex n-person bargaining problems, they generally yield Pareto efficient solution outcomes, and asymmetries among bargainers are captured by a single parameter ve...
Ji-Huan He
2011-01-01
A new fractal derive is defined, which is very easy for engineering applications to discontinuous problems, two simple examples are given to elucidate to establish governing equations with fractal derive and how to solve such equations, respectively.
William J. McDonough
1993-01-01
Remarks on Derivatives: Practices and Principles, a report by the Global Derivatives Study Group of the Group of Thirty, presented at the Group of Thirty Meeting, Washington, D.C., September 27, 1993.
Multi loop soliton solutions and their interactions in the Degasperis-Procesi equation
Stalin, S.; Senthilvelan, M.
2012-01-01
In this article, we construct loop soliton solutions and mixed soliton - loop soliton solution for the Degasperis-Procesi equation. To explore these solutions we adopt the procedure given by Matsuno. By appropriately modifying the $\\tau$-function given in the above paper we derive these solutions. We present the explicit form of one and two loop soliton solutions and mixed soliton - loop soliton solutions and investigate the interaction between (i) two loop soliton solutions in different para...
Rene M. Stulz
2004-01-01
This paper discusses the extent to which derivatives pose threats to firms and to the economy. After reviewing the derivatives markets and putting in perspective the various measures of the size of these markets, the paper shows who uses derivatives and why. The difficulties firms face in valuing derivatives portfolios are evaluated. Although academics pay much attention to no-arbitrage pricing results, the paper points out that there can be considerable subjectivity in the pricing of derivat...
Derivatives in emerging markets
Dubravko Mihaljek; Frank Packer
2010-01-01
Turnover of derivatives has grown more rapidly in emerging markets than in developed countries. Foreign exchange derivatives are the most commonly traded of all risk categories, with increasingly frequent turnover in emerging market currencies and a growing share of cross-border transactions. As the global reach of the financial centres in emerging Asia has expanded, the offshore trading of many emerging market currency derivatives has risen as well. Growth in derivatives turnover is positive...
Asymptotic Behavior of Periodic Wave Solution to the Hirota-Satsuma Equation
Institute of Scientific and Technical Information of China (English)
WU Yong-Qi
2011-01-01
The one- and two-periodic wave solutions (or the Hirota-Satsuma (HS) equation are presented by using the Hirota derivative and Riemann theta function. The rigorous proofs on asymptotic behaviors of these two solutions are given such that soliton solution can be obtained from the periodic wave solution in an appropriate limiting procedure.%@@ The one- and two-periodic wave solutions for the Hirota-Satsuma (HS) equation are presented by using the Hirota derivative and Riemann theta function.The rigorous proofs on asymptotic behaviors of these two solutions are g/ven such that soliton solution can be obtained from the periodic wave solution in an appropriate limiting procedure.
Corporate Governance Failures in Trading Financial Derivatives
Turegeldiyev, Anuar
2013-01-01
The ultimate goal of the following master thesis is to identify specific mistakes in corporate governance practices that have led to colossal losses in financial derivatives trading departments, to draw lessons from these cases, and to propose possible solutions to prevent such behavior and the consequences that follow.
Synthesis of isothiocyanate-derived mercapturic acids
Vermeulen, M.; Zwanenburg, B.; Chittenden, G.J.F.; Verhagen, H.
2003-01-01
Twelve mercapturic acids derived from saturated and unsaturated aliphatic and aromatic isothiocyanates were synthesised, by adding isothiocyanate to a solution of N-acetyl-L-cysteine and sodium bicarbonate, in a typical yield of 77%. Isothiocyanates were synthesised first by adding the corresponding
Solutions of fractional diffusion equations by variation of parameters method
Directory of Open Access Journals (Sweden)
Mohyud-Din Syed Tauseef
2015-01-01
Full Text Available This article is devoted to establish a novel analytical solution scheme for the fractional diffusion equations. Caputo’s formulation followed by the variation of parameters method has been employed to obtain the analytical solutions. Following the derived analytical scheme, solution of the fractional diffusion equation for several initial functions has been obtained. Graphs are plotted to see the physical behavior of obtained solutions.
A generalisation of the Buchdahl transformation and perfect fluid solutions
International Nuclear Information System (INIS)
Perfect fluid solutions in general relativity are examined. The pressure isotropy relation possesses a discrete symmetry in the derivatives of the metric functions. It is shown that a generalisation of Buchdahl's original transformation (Aust. J. Phys.; 9: 13 (1956)) allows new physically reasonable solutions to be obtained from known solutions. An example is given. Previously noticed first by Buchdahl, and later by Glass and Goldman (J. Math. Phys.; 19: 856 (1978)), this symmetry was thought to lead only to unphysical solutions. (author)
Ions in hyaluronic acid solutions
Horkay, Ferenc; Basser, Peter J.; Londono, David J.; Hecht, Anne-Marie; Geissler, Erik
2009-11-01
Hyaluronic acid (HA) is an anionic biopolymer that is almost ubiquitous in biological tissues. An attempt is made to determine the dominant features that account for both its abundance and its multifunctional role, and which set it apart from other types of biopolymers. A combination of osmotic and scattering techniques is employed to quantify its dynamic and static properties in near-physiological solution conditions, where it is exposed both to mono- and divalent counterions. An equation of state is derived for the osmotic pressure Π in the semidilute concentration region, in terms of two variables, the polymer concentration c and the ionic strength J of the added salt, according to which Π =1.4×103c9/4/J3/4 kPa, where c and J are expressed in mole. Over the physiological ion concentration range, the effect of the sodium chloride and calcium chloride on the osmotic properties of HA solutions is fully accounted for by their contributions to the ionic strength. The absence of precipitation, even at high CaCl2 concentrations, distinguishes this molecule from other biopolymers such as DNA. Dynamic light scattering measurements reveal that the collective diffusion coefficient in HA solutions exceeds that in aqueous solutions of typical neutral polymers by a factor of approximately 5. This property ensures rapid adjustment to, and recovery from, stress applied to HA-containing tissue. Small angle x-ray scattering measurements confirm the absence of appreciable structural reorganization over the observed length scale range 10-1000 Å, as a result of calcium-sodium ion exchange. The scattered intensity in the transfer momentum range q >0.03 Å-1 varies as 1/q, indicating that the HA chain segments in semidilute solutions are linear over an extended concentration range. The osmotic compression modulus c ∂Π/∂c, a high value of which is a prerequisite in structural biopolymers, is several times greater than in typical neutral polymer solutions.
Thermodynamics of fenoxycarb in solution
International Nuclear Information System (INIS)
Highlights: • Solubility of fenoxycarb in alcohols presents strongly non-linear van’t Hoff plots. • Rigorously calculated ideal solubility vs temperature is presented. • The activity coefficients show positive deviation from Raoult’s law. • The activity coefficient derivative dominates the van’t Hoff enthalpy of solution. -- Abstract: The solubility of fenoxycarb has been determined between 278 and 318 K in several organic solvents. The solid phase at equilibrium and some indication of polymorphism has been properly examined by powder XRD, DSC, Raman and ATR-FTIR spectroscopy, solution 1H NMR and SEM. Using literature data the activity of the solid phase within a Raoult’s law definition has been calculated, based on which solution activity coefficients have been estimated. In ethyl acetate, the van’t Hoff enthalpy of solution is constant over the temperature range and equals the melting enthalpy. However, it is shown that the solution is slightly non-ideal with the heat capacity difference term compensating for the activity coefficient term. In toluene, the van’t Hoff enthalpy of solution is constant as well but clearly higher than the melting enthalpy. In methanol, ethanol and isopropanol, van Hoff curves are strongly non-linear, the slope however clearly approaching the melting enthalpy at higher temperatures. In all solvents, positive deviations from Raoult’s law are prevailing. The activity coefficients follow a decreasing order of isopropanol > ethanol > methanol > toluene > ethyl acetate, and in all solvents decrease monotonically with increasing temperature. The highest activity coefficient is about 18 corresponding to about 2.5 kJ/mol of deviation from ideality
Strong shock implosion, approximate solution
Fujimoto, Y.; Mishkin, E. A.; Alejaldre, C.
1983-01-01
The self-similar, center-bound motion of a strong spherical, or cylindrical, shock wave moving through an ideal gas with a constant, γ= cp/ cv, is considered and a linearized, approximate solution is derived. An X, Y phase plane of the self-similar solution is defined and the representative curved of the system behind the shock front is replaced by a straight line connecting the mappings of the shock front with that of its tail. The reduced pressure P(ξ), density R(ξ) and velocity U1(ξ) are found in closed, quite accurate, form. Comparison with numerically obtained results, for γ= {5}/{3} and γ= {7}/{5}, is shown.
Bounding solutions of Pfaff equations
Esteves, E.; Kleiman, S
2003-01-01
Let \\omega be a Pfaff system of differential forms on a projective space. Let S be its singular locus, and Y a solution of \\omega=0. We prove Y\\cap S is of codimension at most 1 in Y, just as Jouanolou suspected; he proved this result assuming \\omega is completely integrable, and asked if the integrability is, in fact, needed. Furthermore, we prove a lower bound on the Castelnuovo--Mumford regularity of Y\\cap S. As in two related articles, we derive upper bounds on numerical invariants of Y, ...
Finite element solutions of free surface flows
Zarda, P. R.; Marcus, M. S.
1977-01-01
A procedure is presented for using NASTRAN to determine the flow field about arbitrarily shaped bodies in the presence of a free surface. The fundamental unknown of the problem is the velocity potential which must satisfy Laplace's equation in the fluid region. Boundary conditions on the free surface may involve second order derivatives in space and time. In cases involving infinite domains either a tractable radiation condition is applied at a truncated boundary or a series expansion is used and matched to the local finite elements. Solutions are presented for harmonic, transient, and steady state problems and compared to either exact solutions or other numerical solutions.
Static scalar field solutions in symmetric gravity
Hossenfelder, S.
2016-09-01
We study an extension of general relativity with a second metric and an exchange symmetry between the two metrics. Such an extension might help to address some of the outstanding problems with general relativity, for example the smallness of the cosmological constant. We here derive a family of exact solutions for this theory. In this two-parameter family of solutions the gravitational field is sourced by a time-independent massless scalar field. We find that the only limit in which the scalar field entirely vanishes is flat space. The regular Schwarzschild-solution is left with a scalar field hidden in the second metric’s sector.
Institute of Scientific and Technical Information of China (English)
李志刚; 贲亮; 韩宇; 毕薇薇
2015-01-01
背景：干细胞制备完成后的放置时间与其存活率的关系是临床应用安全、有效的基础。目的：观察不同保存液及不同保存时间对脐带源间充质干细胞存活率的影响，为干细胞有效期的确定提供重要依据。方法：选用脐带源间充质干细胞制备干细胞制剂，分别采用生理盐水、培养基、培养基+生理盐水、生理盐水含表皮生长因子、培养基含低分子肝素钙悬浮保存。使用冷藏箱模拟细胞运输条件，分别在第0，6，12，18，24，30，36，42，48小时取样，进行细胞总数和细胞活率的检测。结果与结论：各组在24 h内的细胞数量和细胞活率差别不大。24 h后，培养基组和培养基含低分子肝素钙组的细胞总数和细胞活率优于生理盐水含因子组、生理盐水组、培养基+生理盐水组。干细胞制剂制备完成后，冷藏运输24 h内细胞活率可达90%以上，保存液中的营养成分及合适的pH值，可使细胞活率显著提高。%BACKGROUND:The relationship between placing time after stem cel preparation and cel survival is the basis of safety and effectiveness for the clinical application. OBJECTIVE: To observe effects of different preservation solutions and different storage time on survival rate of umbilical cord-derived mesenchymal stem cels, and to provide important evidence for identifying effectiveness of stem cels. METHODS:Umbilical cord-derived mesenchymal stem cels were selected to prepare stem cel preparation, which was preserved in physiological saline, medium, medium+physiological saline, physiological saline containing epidermal growth factor, and medium containing low molecular heparin calcium suspension. Cold closet was selected for imitating celular transport conditions. Samples were obtained at 0, 6, 12, 18, 24, 30, 36, 42 and 48 hours. Total cel number and cel survival rate were detected. RESULTS AND CONCLUSION:The difference in cel number and
Generalized \\delta-Derivations
Kaygorodov, Ivan
2011-01-01
We defined generalized \\delta-derivations of algebra A as linear mapping \\chi associated with usual \\delta-derivation \\phi by the rule \\chi(xy)=\\delta(\\chi(x)y+x\\phi(y))=\\delta(\\phi(x)y+x\\chi(y)) for any x,y \\in A. We described generalized \\delta-derivations of prime alternative algebras, prime Lie algebras and superalgebras, unital algebras, and semisimple finite-dimensional Jordan superalgebras. In this cases we proved that generalized \\delta-derivation is a generalized derivation or \\delta...
NONLINEAR WAVES AND PERIODIC SOLUTION IN FINITE DEFORMATION ELASTIC ROD
Institute of Scientific and Technical Information of China (English)
Liu Zhifang; Zhang Shanyuan
2006-01-01
A nonlinear wave equation of elastic rod taking account of finite deformation, transverse inertia and shearing strain is derived by means of the Hamilton principle in this paper. Nonlinear wave equation and truncated nonlinear wave equation are solved by the Jacobi elliptic sine function expansion and the third kind of Jacobi elliptic function expansion method. The exact periodic solutions of these nonlinear equations are obtained, including the shock wave solution and the solitary wave solution. The necessary condition of exact periodic solutions, shock solution and solitary solution existence is discussed.
Exact monochromatic finite power beam solutions of Maxwells equations in vacuum
Hellwarth, Robert W
2016-01-01
We derived and discussed new exact, monochromatic, finite-power, beam-like solutions of Maxwells equations in vacuum. We derived energy density flux, total power of the solution, and compared its effective beam area with that of the Gaussian beam solution.
Solutions of the Bohr hamiltonian, a compendium
Fortunato, L
2004-01-01
The Bohr hamiltonian, also called collective hamiltonian, is one of the cornerstone of nuclear physics and a wealth of solutions (analytic or approximated) of the associated eigenvalue equation have been proposed over more than half a century (confining ourselves to the quadrupole degree of freedom). Each particular solution is associated with a peculiar form for the $V(\\beta,\\gamma)$ potential. The large number and the different details of the mathematical derivation of these solutions, as well as their increased and renewed importance for nuclear structure and spectroscopy, demand a thorough discussion. It is the aim of the present monograph to present in detail all the known solutions in $\\gamma-$unstable and $\\gamma-$stable cases, in a taxonomic and didactical way. In pursuing this task we especially stressed the mathematical side leaving the discussion of the physics to already published comprehensive material. The paper contains also a new approximate solution for the linear potential, and a new solutio...
Cosmological Solutions of $f(T)$ Gravity
Paliathanasis, Andronikos; Leach, P G L
2016-01-01
In the cosmological scenario in $f\\left( T\\right) $ gravity, we find analytical solutions for an isotropic and homogeneous universe containing a dust fluid and radiation and for an empty anisotropic Bianchi I universe. The method that we apply is that of movable singularities of differential equations. For the isotropic universe, the solutions are expressed in terms of a Laurent expansion, while for the anisotropic universe we find a family of exact Kasner-like solutions in vacuum. Finally, we discuss when a nonlinear $f\\left( T\\right) $-gravity theory provides solutions for the teleparallel equivalence of general relativity and derive conditions for exact solutions of general relativity to solve the field equations of an $f(T)$ theory.
Stable solutions for a catalytic converter
Energy Technology Data Exchange (ETDEWEB)
Byrne, H.; Norbury, J. (Univ. of Oxford (United Kingdom). Mathematical Inst.)
1994-06-01
A coupled system of partial differential equations that describes the evolution of solid and gas temperatures and gas concentration inside a catalytic converter is derived and examined. The use of a reaction term, which is a discontinuous function of the solid temperature and gas concentration, implies that two types of nontrivial solutions may occur. These are characterized by the manner in which the reaction switches off: either the solid temperature becomes too low (U-solutions) or the gaseous concentration is exhausted (G-solutions). This reaction term differs from the usual combustion term because the reaction is modeled as two-stage, with the large activation-energy limit then justifying the step-function approach adopted. First, steady solutions for which the gas and solid are in thermal equilibrium are studied, and a constraint relating the system's parameters is derived as a necessary condition for the existence of such solutions. Explicit solutions are presented for a particular class of reaction rates, with a linear stability analysis of one case indicating that G-solutions are stable while U-solutions are not. Steady solutions for which the solid and gas are no longer in thermal equilibrium are then considered. For a particular asymptotic limit (and choice of the reaction term), the construction of asymptotic power series expansions shows that the gas temperature exceeds the solid temperature at all points inside the converter. The analysis indicates that separate treatment of the solid and gaseous temperatures has no effect on the qualitative nature of the steady solutions, that is, their existence, stability, and parameter dependence.
Existence of Minimizers for Fractional Variational Problems Containing Caputo Derivatives
Bourdin, Loïc; Odzijewicz, Tatiana; Delfim F. M. Torres
2012-01-01
International audience We study dynamic minimization problems of the calculus of variations with Lagrangian functionals containing Riemann–Liouville fractional integrals, classical and Caputo fractional derivatives. Under assumptions of regularity, coercivity and convexity, we prove existence of solutions.
Contact Lens Solution Toxicity
... rash and rashes clinical tools newsletter | contact Share | Contact Lens Solution Toxicity Information for adults A A A This image shows a reaction to contact lens solution. The prominent blood vessels and redness ...
Analytic Solutions of Elastic Tunneling Problems
Strack, O.E.
2002-01-01
The complex variable method for solving two dimensional linearly elastic problems is used to obtain several fundamental analytical solutions of tunneling problems. The method is used to derive the general mathematical representation of problems involving resultant forces on holes in a half-plane
Weak Dynamic Programming Principle for Viscosity Solutions
Bouchard, Bruno; Touzi, Nizar
2011-01-01
We prove a weak version of the dynamic programming principle for standard stochastic control problems and mixed control-stopping problems, which avoids the technical difficulties related to the measurable selection argument. In the Markov case, our result is tailor-maid for the derivation of the dynamic programming equation in the sense of viscosity solutions.
Schwarzschild solution in extended teleparallel gravity
Nashed, G G L
2015-01-01
Tetrad field, with two unknown functions of radial coordinate and an angle $\\Phi$ which is the polar angle $\\phi$ times a function of the redial coordinate, is applied to the field equation of modified theory of gravity. Exact vacuum solution is derived whose scalar torsion, $T ={T^\\alpha}_{\\mu \
Unsteady Stokes Equations: Some Complete General Solutions
Indian Academy of Sciences (India)
A Venkatlaxmi; B S Padmavathi; T Amaranath
2004-05-01
The completeness of solutions of homogeneous as well as non-homogeneous unsteady Stokes equations are examined. A necessary and sufficient condition for a divergence-free vector to represent the velocity field of a possible unsteady Stokes flow in the absence of body forces is derived.
Weak solutions to problems involving inviscid fluids
Feireisl, Eduard
2015-01-01
We consider an abstract functional-differential equation derived from the pressure-less Euler system with variable coefficients that includes several systems of partial differential equations arising in the fluid mechanics. Using the method of convex integration we show the existence of infinitely many weak solutions for prescribed initial data and kinetic energy.
Spectroscopic studies of solutes in aqueous solution.
Chai, Bing-hua; Zheng, Jian-ming; Zhao, Qing; Pollack, Gerald H
2008-03-20
Absorption and fluorescence characteristics of aqueous solutions of salts, sugars, and amino acids were studied using UV-vis spectroscopy and spectrofluorometry. Motivation stemmed from unanticipated absorption spectral and fluorescence features of the "exclusion zone" seen adjacent to various hydrophilic surfaces. Those features implied a structure distinct from that of bulk water (Adv. Colloid Interface Sci. 2006, 127, 19). Absorption peaks at approximately 270 nm similar to those observed in the exclusion zone were seen in solutions of the following substances: salts, Nafion 117 solution/film, l-lysine, d-alanine, d-glucose and sucrose. To determine the fate of the absorbed energy, we studied the fluorescence properties of these solutions. The salts showed fluorescence emission around 480-490 nm under different excitation wavelengths. The fluorescence intensity of LiCl was higher than NaCl, which was in turn higher than KCl-the same ordering as the absorption intensities. Fluorescence of Nafion 117 solution/film, l-lysine, d-alanine, d-glucose and sucrose were observed as well, with multiple excitation wavelengths. Hence, at least some of the absorbed energy is released as fluorescence. The results show features closely similar to those observed in the exclusion zone, implying that the aqueous region around the solutes resembles the aqueous zone adjacent to hydrophilic surfaces. Both may be more extensively ordered than previously thought. PMID:18298105
International Nuclear Information System (INIS)
This Functional Design Criteria (FDC) addresses remediation of the plutonium-bearing solutions currently in inventory at the Plutonium Finishing Plant (PFP). The recommendation from the Environmental Impact Statement (EIS) is that the solutions be treated thermally and stabilized as a solid for long term storage. For solutions which are not discardable, the baseline plan is to utilize a denitration process to stabilize the solutions prior to packaging for storage
An Interacting Dark Energy Model with Nonminimal Derivative Coupling
Nozari, Kourosh
2016-01-01
We study cosmological dynamics of an extended gravitational theory that gravity is coupled non-minimally with derivatives of a dark energy component and there is also a phenomenological interaction between the dark energy and dark matter. Depending on the direction of energy flow between the dark sectors, the phenomenological interaction gets two different signs. We show that this feature affects the existence of attractor solution, the rate of growth of perturbations and stability of the solutions. By considering an exponential potential as a self-interaction potential of the scalar field, we obtain accelerated scaling solutions that are attractors and have the potential to alleviate the coincidence problem. While in the absence of the nonminimal derivative coupling there is no attractor solution for phantom field when energy transfers from dark matter to dark energy, we show an attractor solution exists if one considers an explicit nonminimal derivative coupling for phantom field in this case of energy tran...
The electromagnetic spike solutions
Nungesser, Ernesto; Lim, Woei Chet
2013-12-01
The aim of this paper is to use the existing relation between polarized electromagnetic Gowdy spacetimes and vacuum Gowdy spacetimes to find explicit solutions for electromagnetic spikes by a procedure which has been developed by one of the authors for gravitational spikes. We present new inhomogeneous solutions which we call the EME and MEM electromagnetic spike solutions.
Fractional Derivative and Integral
Aygören, Aysel
2014-01-01
ABSTRACT: In this thesis we studied fractional order derivative and integral. In Chapter1, a brief history on the foundation of fractional derivative and integration has been given. In the second chapter, some definitions and theorems have been provided. Also some needed special functions such as Gamma, Beta, Mittag-Leffler and Wright function have taken place in this chapter. Properties of fractional derivative and integral are discussed in Chapter 3. We started to this chapter by the dis...
Developing a derivatives generator
Directory of Open Access Journals (Sweden)
Mircea Petic
2016-01-01
Full Text Available The article intends to highlight the particularities of the derivational morphology mechanisms that will help in lexical resources extension. Some computing approaches for derivational morphology are given for several languages, inclusively for Romanian. This paper deals with some preprocessing particularities, that are needed in the process of automatic generation. Then, generative mechanisms are presented in the form of derivational formal rules separately for prefixation and suffixation. The article ends with several approaches in automatic new generated words validation.
Lin, Shaowei
2014-01-01
The enactment of derivative action was expected to be actively used by shareholders to protect their interests. In fact, it turned out that this reform effort seemed futile as the right to engage in such actions was rarely exercised. This raises a question about the role of derivative actions in China; namely, should a derivative action system play a key role in protecting shareholder interests? If the answer is positive, the next question is how such a system could be improved...
Langmuir-Blodgett Films of Graphene Derivatives
DEFF Research Database (Denmark)
Petersen, Søren Vermehren
The work presented in this PhD thesis can be divided into two main categories: 1) Syn-thesis and Langmuir-Blodgett assembly of graphene derivatives and 2) Application and characterization of graphene derivatives as an interface material in molecular electron-ics. While the first category could...... be divided further, the synthesis and Langmuir-Blodgett results are intertwined in such a way that it would be more confusing to pre-sent them separately. The Langmuir-Blodgett deposition also played a crucial, but more isolated, part in the investigation of graphene derivatives as interface material....... Solution processable graphene in the form of chemically derived graphene has been synthesized through the modified Hummers method with subsequent reduction into reduced graphene oxide with hydrazine. The completeness of oxidation, the effect of the refinement steps and the reduction of the graphene oxide...
Partially self-similar solutions in general relativity
International Nuclear Information System (INIS)
The definition of self-similar spacetimes is extended from homothetic spacetimes to partially homothetic ones, and a new type of solutions is obtained by solving ordinary differential equations derived from the Einstein equations. (author)
Proteins in solution: Fractal surfaces in solutions
Directory of Open Access Journals (Sweden)
R. Tscheliessnig
2016-02-01
Full Text Available The concept of the surface of a protein in solution, as well of the interface between protein and 'bulk solution', is introduced. The experimental technique of small angle X-ray and neutron scattering is introduced and described briefly. Molecular dynamics simulation, as an appropriate computational tool for studying the hydration shell of proteins, is also discussed. The concept of protein surfaces with fractal dimensions is elaborated. We finish by exposing an experimental (using small angle X-ray scattering and a computer simulation case study, which are meant as demonstrations of the possibilities we have at hand for investigating the delicate interfaces that connect (and divide protein molecules and the neighboring electrolyte solution.
Computational Derivation to Zeta Zeros and Prime Numbers
Chalmers, Gordon
2005-01-01
A route to the derivation of the numbers $s$ to the transcendental equation $\\zeta(s)=0$ is presented. The solutions to this equation require the solving of a geodesic flow in an infinite dimensional manifold. These solutions enable one approach to a formula generating the prime numbers.
Molecular Thermodynamic Modeling of Fluctuation Solution Theory Properties
DEFF Research Database (Denmark)
O’Connell, John P.; Abildskov, Jens
2013-01-01
Fluctuation Solution Theory provides relationships between integrals of the molecular pair total and direct correlation functions and the pressure derivative of solution density, partial molar volumes, and composition derivatives of activity coefficients. For dense fluids, the integrals follow a...... relatively simple corresponding-states behavior even for complex systems, show welldefined relationships for infinite dilution properties in complex and near-critical systems, allow estimation of mixed-solvent solubilities of gases and pharmaceuticals, and can be expressed by simple perturbation models for...
Cosmological Models with Fractional Derivatives and Fractional Action Functional
Institute of Scientific and Technical Information of China (English)
V.K. Shchigolev
2011-01-01
Cosmological models of a scalar field with dynamical equations containing fractional derivatives or derived from the Einstein-Hilbert action of fractional order, are constructed. A number of exact solutions to those equations of fractional cosmological models in both eases is given.
International Nuclear Information System (INIS)
The chemical preparation of 26,27-isotopically labelled vitamin D3 derivatives of high specific activity is described. These labelled vitamin D derivatives are useful in the determination of vitamin D metabolite levels in the blood and tissues of man and animals. (U.K.)
Numerical Integration with Derivatives
Institute of Scientific and Technical Information of China (English)
Hu Cheng
2006-01-01
A new formula with derivatives for numerical integration was presented. Based on this formula and the Richardson extrapolation process, a numerical integration method was established. It can converge faster than the Romberg's. With the same accuracy, the computation of the new numerical integration with derivatives is only half of that of Romberg's numerical integration.
Ulrich Kirchner
2010-01-01
We present an approach to derivative exposure management based on subjective and implied probabilities. We suggest to maximize the valuation difference subject to risk constraints and propose a class of risk measures derived from the subjective distribution. We illustrate this process with specific examples for the two and three dimensional case. In these cases the optimization can be performed graphically.
Lokar, Matija
This paper describes several projects concerning the use of the DERIVE programming language for symbolic computation in Slovenia. The main topics discussed include preparing books and materials using DERIVE in Slovenian language, and a survey on the use of programs for symbolic computation by mathematics teachers in Slovenian secondary schools.…
Blumenstyk, Goldie
1994-01-01
Heavy investment in derivatives, whose value derives from the price movement of some underlying security, has meant heavy losses for some colleges and universities despite the fact that institutional investors are required to assure that they understand the risks of such investment. (MSE)
Yusuke Osaki
2007-01-01
We consider an asset market traded three types of assets: the risk–free asset, the market portfolio and derivatives written on the market portfolio return. We determine a sufficient condition to guarantee that noise risk monotonically changes their derivatives. The condition is that Arrow–Pratt absolute risk aversion is decreasing and convex.
BIFURCATIONS OF TRAVELLING WAVE SOLUTIONS TO A COUPLED NONLINEAR WAVE SYSTEM
Institute of Scientific and Technical Information of China (English)
无
2008-01-01
Employ theory of bifurcations of dynamical systems to a system of coupled nonlin-ear equations, the existence of solitary wave solutions, kink wave solutions, anti-kink wave solutions and periodic wave solutions is obtained. Under different parametric conditions, various suffcient conditions to guarantee the existence of the above so-lutions are given. Some exact explicit parametric representations of travelling wave solutions are derived.
Jacobi elliptic function solutions of the Ablowitz-Ladik discrete nonlinear Schroedinger system
International Nuclear Information System (INIS)
A new general Jacobi elliptic function expansion algorithm is developed to obtain exact solutions for discrete nonlinear systems. Applying this method, many exact Jabobi elliptic function travelling wave solutions for Ablowitz-Ladik discrete nonlinear Schroedinger system are derived. These doubly periodic solutions may degenerate to hyperbolic function solutions including discrete soliton solutions as the modulus m → 1 and trigonometric function solutions as m → 0, respectively.
Duer, W. C.; And Others
1977-01-01
Discusses comparisons of packing densities derived from known molar volume data of liquids and solutions. Suggests further studies for using assemblies of spheres as models for simple liquids and solutions. (MLH)
International Nuclear Information System (INIS)
A solution mining process which may be used for uranium, thorium, vanadium, copper, nickel, molybdenum, rhenium, and selenium is claimed. During a first injection-and-production phase of between 6 months and 5 years, a leaching solution is injected through at least one well into the formation to solubilize the mineral values and form a pregnant liquor. This liquor is recovered through another well. The leaching solution contains sulfuric acid, nitric acid, hydrochloric acid, carbonic acid, an alkali metal carbonate, an alkali metal bicarbonate, ammonium carbonate or ammonium bicarbonate. Subsequently during a first production-only phase of between about 2 weeks and one year, injection of the leaching solution is suspended but pregnant liquor is still recovered. This stage is followed by a second injection-and-production phase of between 6 months and 5 years and a second production-only phase. The mineral values are separated from the pregnant liquor to form a barren liquor. The leaching agent is introduced into this liquor, and the solution is recycled. In a second claim for the solution mining of uranium, dilute carbonic acid is used as the leaching solution. The solution has a pH less than 7 and a bicarbonate ion concentration between about 380 ppm and 1000 ppm. The injection-and-production phase lasts between one and two years and the production only phase takes between one and four months. Carbon dioxide is introduced into the barren liquor to form a dilute carbonic acid solution and the solution is recycled
DEFF Research Database (Denmark)
Dyppel, Katja Joo
2013-01-01
The main objective for this thesis is to analyse and systematise the Danish legislation on taxation of derivatives. According to financial terminology, a derivative is a financial instrument. Its value is derived from changes in the value of one or more underlying assets.The most common derivatives...... in the Danish tax legislation. However, contracts known as forwards (terminskontrakter) and options (aftaler om køberetter og salgsretter) are generally included in the term financials contracts covered by the Danish Act on Taxation of Gains and Losses on Claims and Debt. The main part of the analysis deals...... with the scope of sections 29-33 of the Danish Act on Taxation of Gains and Losses on Claims and Debt and the tax consequences for the covered financial contracts. In the analysis of taxation of derivatives, the fundamental issues of qualification and tax treatment of the instruments are dealt with....
Approximate analytical solutions to the condensation-coagulation equation of aerosols
DEFF Research Database (Denmark)
Smith, Naftali R.; Shaviv, Nir J.; Svensmark, Henrik
2016-01-01
We present analytical solutions to the steady state nucleation-condensation-coagulation equation of aerosols in the atmosphere. These solutions are appropriate under different limits but more general than previously derived analytical solutions. For example, we provide an analytic solution to the...
Exact Solutions for a Higher-Order Nonlinear Schr(o)dinger Equation in Atmospheric Dynamics
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
By giving prior assumptions on the form of the solutions, we succeed to find several exact solutions for a higher-order nonlinear Schrodinger equation derived from one important model in the study of atmospheric and ocean dynamical systems. Our analytical solutions include bright and dark solitary waves, and periodical solutions, which can be used to explain atmospheric phenomena.
MULTIPLE SOLITON SOLUTIONS OF SECOND-ORDER BENJAMIN-ONO EQUATION
Mohammad Najafi
2012-01-01
We employ the idea of Hirotas bilinear method, to obtain some new exact soliton solutions for high nonlinear form of Multiple soliton solutions of secondorder Benjamin-Ono equation. Multiple singular soliton solutions were obtained by this method. Moreover, multiple singular soliton solutions were also derived.
The Adsorption Effect of Quaternized Chitosan Derivatives on Bile Acid
Institute of Scientific and Technical Information of China (English)
Shu Xian MENG; Ya Qing FENG; Wen Jin LI; Cai Xia YIN; Jin Ping DENG
2006-01-01
Three quaternized chitosan derivatives were synthesized and their adsorption performance of bile acid from aqueous solution was studied. The adsorption capacities and rates of bile acid onto quaternized chitosan derivatives were evaluated. The kinetic experimental data properly correlated with the second-order kinetic model, which indicated that the chemical sorption is the rate-limiting step. The results showed that the quaternized chitosan derivatives are favorable adsorbents for bile acid.
Determination of Ascorbic Acid in Vegetables by Derivative Spectrophotometry
Aydoğmuş, Zeynep; ÇETİN, Sevil Müge
2002-01-01
Determination of ascorbic acid (AA) in garlic, green pepper and chestnut was performed by derivative spectrophotometry without using any pre-separation or background correction techniques. The method is based on the measurement of the distances between two extremum values (peak-to-peak amplitudes) in second and third order derivative spectra of the extracts. Ten percent trichloroacetic acid was found to be the most suitable extraction solution. In the second order derivative spectru...
A 'simple' hybrid model for power derivatives
International Nuclear Information System (INIS)
This paper presents a method for valuing power derivatives using a supply-demand approach. Our method extends work in the field by incorporating randomness into the base load portion of the supply stack function and equating it with a noisy demand process. We obtain closed form solutions for European option prices written on average spot prices considering two different supply models: a mean-reverting model and a Markov chain model. The results are extensions of the classic Black-Scholes equation. The model provides a relatively simple approach to describe the complicated price behaviour observed in electricity spot markets and also allows for computationally efficient derivatives pricing. (author)
Solutions to Organizational Paradox
DEFF Research Database (Denmark)
Li, Xin; Worm, Verner; Peihong, Xie
Organizations face all kinds of paradoxical problems. There exist various solutions to organizational paradoxes. We develop a typology that lists nine possible logical approaches to understanding the relationship between paradoxical opposites, out of which we identify five types of solutions to...... organizational paradox. Four of the five solutions are explicitly associated with four prominent philosophies. We show the relevance of the five solutions to the real world by applying our scheme to understand different solutions to the generic strategy paradox. Finally, we address the question whether there is...... a superior solution and point out the paradox of paradox resolving, namely, paradoxes cannot be resolved once for all and we have to live with them....
Charged Vaidya Solution Satisfies Weak Energy Condition
Chatterjee, Soumyabrata; Virmani, Amitabh
2015-01-01
The external matter stress-tensor supporting charged Vaidya solution appears to violate weak energy condition in certain region of the spacetime. Motivated by this, a new interpretation of charged Vaidya solution was proposed by Ori [1] in which the energy condition continues to be satisfied. In this construction, one glues an outgoing Vaidya solution to the original ingoing Vaidya solution provided the surface where the external stress-tensor vanishes is spacelike. We revisit this study and extend it to higher-dimensions, to AdS settings, and to higher-derivative f(R) theories. In asymptotically flat space context, we explore in detail the case when the mass function m(v) is proportional to the charge function q(v). When the proportionality constant \
Explicit solutions of two nonlinear dispersive equations with variable coefficients
International Nuclear Information System (INIS)
A mathematical technique based on an auxiliary equation and the symbolic computation system Matlab is developed to construct the exact solutions for a generalized Camassa-Holm equation and a nonlinear dispersive equation with variable coefficients. It is shown that the variable coefficients of the derivative terms in the equations cause the qualitative change in the physical structures of the solutions
Exact cosmological solutions of scale-invariant gravity theories
Barrow, J D; Barrow, John D.
2006-01-01
We have found new anisotropic vacuum solutions for the scale-invariant gravity theories which generalise Einstein's general relativity to a theory derived from the Lagrangian $R^{1+\\delta}$. These solutions are expanding universes of Kasner form with an initial spacetime singularity at $t=0 $ and exist for $-1/20$.
Analytical Solution of the Time Fractional Fokker-Planck Equation
Directory of Open Access Journals (Sweden)
Sutradhar T.
2014-05-01
Full Text Available A nonperturbative approximate analytic solution is derived for the time fractional Fokker-Planck (F-P equation by using Adomian’s Decomposition Method (ADM. The solution is expressed in terms of Mittag- Leffler function. The present method performs extremely well in terms of accuracy, efficiency and simplicity.
Spurious solutions of three-dimensional Faddeev equations
International Nuclear Information System (INIS)
The spurious solutions of the three-dimensional Faddeev equations, written in the representation of total angular momentum and total spatial parity, are derived explicitly. It is shown how one can use the spurious solutions as standard ones in testing the numerical algorithms for solving these equations
Approximate solution of the pairing Hamiltonian in the Berggren basis
Mercenne, A; Ploszajczak, M
2015-01-01
We derive the approximate solution for the pairing Hamiltonian in the Berggren ensemble of single particle states including bound, resonance and non-resonant scattering states. We show that this solution is reliable in the limit of a weak pairing interaction.
Quadrature of an integral solution of slowing down transport equation
International Nuclear Information System (INIS)
Full text: Numerical solution of the slowing-down equation is derived from analytical solution for neutron flux for given values of energy. It is shown in this paper that the application of Newton interpolation for obtaining effective cross sections as well as Gauss quadrature formula for numerical integration is justified
Exact Solutions for Compact Objects in General Relativity
Raghoonundun, Ambrish M
2016-01-01
Seven new solutions to the interior static and spherically symmetric Einstein's field equations (EFE) are found and investigated. These new solutions are a generalisation of the quadratic density fall-off profile of the Tolman VII solution. The generalisation involves the addition of anisotropic pressures and electric charge to the density profile. Of these new solutions three are found to obey all the necessary conditions of physical acceptability, including linear stability under radial perturbations, and causality of the speed of pressure waves inside the object. Additionally an equation of state can be found for all the physically viable solutions. The generalised pulsation equation for interior solutions to the EFE that include both electric charge and pressure anisotropy is derived and used to determine the stability of the solutions. However the pulsation equation found is general and can be used for all new solutions that contain these ingredients.
Strategy to Construct Exact Solutions in Einstein-Scalar Gravities
Wen, Qiang
2015-01-01
In this article we propose a new efficient strategy to construct exact solutions of Einstein gravities with a minimally coupled self-interacting scalar field. The strategy is to use the symmetry of the equations of motion (EOMs) to give a proper ansatz for scalar field first, then derive the metric and the corresponding scalar potential later. Using this strategy we give a simple example of constructing exact circular solutions in three dimensional gravities, these solutions contain the HMTZ ...
General static spherically symmetric solutions in Horava gravity
Capasso, Dario
2009-01-01
We derive general static spherically symmetric solutions in the Horava theory of gravity with nonzero shift field. These represent "hedgehog" versions of black holes with radial "hair" arising from the shift field. For the case of the standard de Witt kinetic term (lambda =1) there is an infinity of solutions that exhibit a deformed version of reparametrization invariance away from the general relativistic limit. Special solutions also arise in the anisotropic conformal point lambda = 1/3.
Numerical integration of asymptotic solutions of ordinary differential equations
Thurston, Gaylen A.
1989-01-01
Classical asymptotic analysis of ordinary differential equations derives approximate solutions that are numerically stable. However, the analysis also leads to tedious expansions in powers of the relevant parameter for a particular problem. The expansions are replaced with integrals that can be evaluated by numerical integration. The resulting numerical solutions retain the linear independence that is the main advantage of asymptotic solutions. Examples, including the Falkner-Skan equation from laminar boundary layer theory, illustrate the method of asymptotic analysis with numerical integration.
Multiple optimal solutions to a sort of nonlinear optimization problem
Institute of Scientific and Technical Information of China (English)
Xue Shengjia
2007-01-01
The optimization problem is considered in which the objective function is pseudolinear(both pseudoconvex and pseudoconcave) and the constraints are linear. The general expression for the optimal solutions to the problem is derived with the representation theorem of polyhedral sets, and the uniqueness condition of the optimal solution and the computational procedures to determine all optimal solutions ( ifthe uniqueness condition is not satisfied ) are provided. Finally, an illustrative example is also given.
New Rational Form Solutions to mKdV Equation
Institute of Scientific and Technical Information of China (English)
FU Zun-Tao; LIU Shi-Kuo; LIU Shi-Da
2005-01-01
In this paper, new basic functions, which are composed of three basic Jacobi elliptic functions, are chosen as components of finite expansion. This finite expansion can be taken as an ansatz and applied to solve nonlinear wave equations. As an example, mKdV equation is solved, and more new rational form solutions are derived, such as periodic solutions of rational form, solitary wave solutions of rational form, and so on.
Enthalpy of solution of CO2 in aqueous solutions of 2-amino-2-methyl-1-propanol
International Nuclear Information System (INIS)
The enthalpies of solution of CO2 in aqueous solution of 2-amino-2-methyl-1-propanol (AMP) 15 wt% and 30 wt% were measured at 322.5 K and pressures range from (0.2 to 5) MPa using a flow calorimetric technique. The gas solubilities were simultaneously determined from the calorimetric data. The solubilities were compared to available literature values obtained by direct measurements. The experimental enthalpies of solution were compared to the values derived from the literature vapor liquid equilibrium data. This work provides calorimetric data that will be used later for the development of a thermodynamic model to predict both solubilities and enthalpies of solution of acid gases in aqueous amine solutions
Brain derived neurotrophic factor
DEFF Research Database (Denmark)
Mitchelmore, Cathy; Gede, Lene
2014-01-01
Brain Derived Neurotrophic Factor (BDNF) is a neurotrophin with important functions in neuronal development and neuroplasticity. Accumulating evidence suggests that alterations in BDNF expression levels underlie a variety of psychiatric and neurological disorders. Indeed, BDNF therapies are...
Exact N-envelope-soliton solutions of the Hirota equation
Shu, Jian-Jun
2014-01-01
We discuss some properties of the soliton equations of the type, partial derivative u/partial derivative t = S [u, (u) over bar], where S is a nonlinear operator differential in x, and present the additivity theorems of the class of the soliton equations. On using the theorems, we can construct a new soliton equation through two soliton equations with similar properties. Meanwhile, exact N-envelope-soliton solutions of the Hirota equation are derived through the trace method.
American derivatives : a review
Aase, Knut K.
1997-01-01
The paper gives an overview over the theory of pricing and hedging financial derivatives that can be exercised at any time during a fixed time interval [0, T]. The analysis makes use of the theory of optimal stopping, and as such it constitutes an interesting application of probability theory to the theory of financial economics. In this paper we concentrate on the main principles involved only, which means, for example, that we abstract from derivatives where the underlying asset pays ou...
DEFF Research Database (Denmark)
Singh, Shailja; Agarwal, Drishti; Sharma, Kumkum;
2016-01-01
Synthetic quinoline derivatives continue to be considered as candidates for new drug discovery if they act against CQ-resistant strains of malaria even after the widespread emergence of resistance to CQ. In this study, we explored the activities of two series of new 4-aminoquinoline derivatives and...... structure activity relationship to find lead molecules for treating multidrug-resistant Plasmodium falciparum and Plasmodium vivax....
Brain derived neurotrophic factor
DEFF Research Database (Denmark)
Mitchelmore, Cathy; Gede, Lene
2014-01-01
Brain Derived Neurotrophic Factor (BDNF) is a neurotrophin with important functions in neuronal development and neuroplasticity. Accumulating evidence suggests that alterations in BDNF expression levels underlie a variety of psychiatric and neurological disorders. Indeed, BDNF therapies are curre......Brain Derived Neurotrophic Factor (BDNF) is a neurotrophin with important functions in neuronal development and neuroplasticity. Accumulating evidence suggests that alterations in BDNF expression levels underlie a variety of psychiatric and neurological disorders. Indeed, BDNF therapies...
Particle production in higher derivative theory
Indian Academy of Sciences (India)
G P Singh; A Beesham; R V Deshpande
2000-05-01
The effect of particle production on the evolution of the spatially ﬂat Friedmann–Lemaitre–Robertson–Walker cosmological model during the early stages of the universe is analysed in the framework of higher derivative theory. The universe has been considered as an open thermodynamic system where particle production gives rise to a supplementary negative creation pressure in addition to the thermodynamic pressure. The dynamical behaviour of both exponential as well as power law solutions have been discussed.
Mitigating systemic risk in OTC derivative markets.
Wellink, N.
2010-01-01
The financial crisis has demonstrated that turmoil in OTC derivative markets can exacerbate financial distress. One of the challenges policymakers currently face, is to mitigate the risks these markets pose to the financial system. Inducing a shift towards more central clearing is an important step in the right direction as it tempers counterparty risk and increases transparency. However, this will only be part of the solution as risk management systems of Central Counterparties (CCPs) are no...
Another exact inflationary solution
Kruger, A T; Kruger, Adam T.; Norbury, John W.
2000-01-01
A new closed-form inflationary solution is given for a hyperbolic interaction potential. The method used to arrive at this solution is outlined as it appears possible to generate additional sets of equations which satisfy the model. In addition a new form of decaying cosmological constant is presented.
Neace, James C.
1986-01-01
Process for removing diluent degradation products from a solvent extraction solution, which has been used to recover uranium and plutonium from spent nuclear fuel. A wash solution and the solvent extraction solution are combined. The wash solution contains (a) water and (b) up to about, and including, 50 volume percent of at least one-polar water-miscible organic solvent based on the total volume of the water and the highly-polar organic solvent. The wash solution also preferably contains at least one inorganic salt. The diluent degradation products dissolve in the highly-polar organic solvent and the organic solvent extraction solvent do not dissolve in the highly-polar organic solvent. The highly-polar organic solvent and the extraction solvent are separated.
Horizon Supertranslation and Degenerate Black Hole Solution
Cai, Rong-Gen; Zhang, Yun-Long
2016-01-01
In this note we first review the degenerate vacua arising from the BMS symmetries. According to the discussion in [1] one can define BMS-analogous supertranslation and superrotation for spacetime with black hole in Gaussian null coordinates. In the leading and subleading orders of near horizon approximation, the infinitely degenerate black hole solutions are derived by considering Einstein equations with or without cosmological constant, and they are related to each other by the diffeomorphism generated by horizon supertranslation. Higher order results and degenerate Rindler horizon solutions also are given in appendices.
Exact solutions for Weyl fermions with gravity
Cianci, Roberto; Vignolo, Stefano
2015-01-01
We consider the single-handed spinor field in interaction with its own gravitational field described by the set of field equations given by Weyl field equations written in terms of derivatives that are covariant with respect to the gravitational connection plus Einstein field equations soured with the energy tensor of the spinor: for the Weyl spinor and the ensuing spacetime of Weyl-Lewis-Papapetrou structure, we will find all exact solutions. The solutions are flag-dipole PP-waves in a VSI-spacetime, and some of their properties are discussed in view of future developments.
Fuzzy Symmetric Solutions of Fuzzy Matrix Equations
Xiaobin Guo; Dequan Shang
2012-01-01
The fuzzy symmetric solution of fuzzy matrix equation AX˜=B˜, in which A is a crisp m×m nonsingular matrix and B˜ is an m×n fuzzy numbers matrix with nonzero spreads, is investigated. The fuzzy matrix equation is converted to a fuzzy system of linear equations according to the Kronecker product of matrices. From solving the fuzzy linear system, three types of fuzzy symmetric solutions of the fuzzy matrix equation are derived. Finally, two examples are given to illustrate the proposed method....
New Five Dimensional Spherical Vacuum Solutions
Roberts, Mark D
2009-01-01
A new five dimensional spherical vacuum solution is both dervied and its signature, curvature and truncation discussed. Its truncation leads to a four dimensional spacetime with similiar stress to those found by charge-free Kaluza-Klein compactification. Various other restrictions to four dimensions are looked at to see if they have stresses consisting of electromagnetic fields or quadratic tensors. The solution is extended to the brane picture where the extended space is found to obey field equations with metric stress derivable from a lagrangian dependent on brane function and kaluza scalar.
Exact solutions for Weyl fermions with gravity
Energy Technology Data Exchange (ETDEWEB)
Cianci, Roberto; Fabbri, Luca; Vignolo, Stefano [Universita di Genova, DIME Sez. Metodi e Modelli Matematici, Genoa (Italy)
2015-10-15
We consider the single-handed spinor field in interaction with its own gravitational field described by the set of field equations given by the Weyl field equations written in terms of derivatives that are covariant with respect to the gravitational connection plus Einstein field equations soured with the energy tensor of the spinor: for the Weyl spinor and the ensuing spacetime of Weyl-Lewis-Papapetrou structure, we find all exact solutions. The obtained solution for the metric tensor is that of a PP-wave spacetime, while the spinor field is a flag-dipole. (orig.)
A New Solution to the Problem of Finding All Numerical Solutions to Ordered Metric Structures.
Lehner, Paul E.; Norma, Elliot
1980-01-01
A new algorithm is used to test and describe the set of all possible solutions for any linear model of an empirical ordering derived from techniques such as additive conjoint measurement, unfolding theory, general Fechnerian scaling, and ordinal multiple regression. The algorithm is computationally faster and numerically superior to previous…
Multivariate statistics exercises and solutions
Härdle, Wolfgang Karl
2015-01-01
The authors present tools and concepts of multivariate data analysis by means of exercises and their solutions. The first part is devoted to graphical techniques. The second part deals with multivariate random variables and presents the derivation of estimators and tests for various practical situations. The last part introduces a wide variety of exercises in applied multivariate data analysis. The book demonstrates the application of simple calculus and basic multivariate methods in real life situations. It contains altogether more than 250 solved exercises which can assist a university teacher in setting up a modern multivariate analysis course. All computer-based exercises are available in the R language. All R codes and data sets may be downloaded via the quantlet download center www.quantlet.org or via the Springer webpage. For interactive display of low-dimensional projections of a multivariate data set, we recommend GGobi.
Constructing analytic approximate solutions to the Lane–Emden equation
International Nuclear Information System (INIS)
We derive analytic approximations to the solutions of the Lane–Emden equation, a basic equation in Astrophysics that describes the Newtonian equilibrium structure of a self-gravitating polytropic fluid sphere. After recalling some basic results, we focus on the construction of rational approximations, discussing the limitations of previous attempts, and providing new accurate approximate solutions. - Highlights: • We make a critical survey of the literature concerning the Lane–Emden equation. • We discuss problems in the construction of accurate rational approximate solutions. • We derive new analytic approximations of interest for star and cluster dynamics
Stochastic derivative and heat type PDEs
Udriste, Constantin; Tevy, Ionel
2011-01-01
In this paper we address again the problem of the connection between multitime Brownian sheet and heat type PDEs. The main results include: the volumetric character of the solutions of the forward (backward) diffusion-like PDEs; the forward mean value of a Brownian process as the solution of the forward heat PDE; the backward mean value of a Brownian process as the solution of the backward heat PDE; the multitime stochastic processes with volumetric dependence; the stochastic partial derivative of a stochastic process with respect to a multitime Wiener process; Hermite polynomials stochastic processes; union of Tzitzeica hypersurfaces (constant level sets of multitime stochastic processes with volumetric dependence). The original results permit to extend the complete integrability theory to multitime stochastic differential systems, using path independent curvilinear integrals and volumetric dependence.
Discrete derivative estimation in LISA Pathfinder data reduction
Ferraioli, Luigi; Vitale, Stefano
2009-01-01
Data analysis for the LISA Technology package (LTP) experiment to be flown aboard the LISA Pathfinder mission requires the solution of the system dynamics for the calculation of the force acting on the test masses (TMs) starting from interferometer position data. The need for a solution to this problem has prompted us to implement a discrete time domain derivative estimator suited for the LTP experiment requirements. We first report on the mathematical procedures for the definition of two methods; the first based on a parabolic fit approximation and the second based on a Taylor series expansion. These two methods are then generalized and incorporated in a more general class of five point discrete derivative estimators. The same procedure employed for the second derivative can be applied to the estimation of the first derivative and of a data smoother allowing defining a class of simple five points estimators for both. The performances of three particular realization of the five point second derivative estimat...
Derivation of a poroelastic flexural shell model
Mikelic, Andro
2015-01-01
In this paper we investigate the limit behavior of the solution to quasi-static Biot's equations in thin poroelastic flexural shells as the thickness of the shell tends to zero and extend the results obtained for the poroelastic plate by Marciniak-Czochra and Mikeli\\'c. We choose Terzaghi's time corresponding to the shell thickness and obtain the strong convergence of the three-dimensional solid displacement, fluid pressure and total poroelastic stress to the solution of the new class of shell equations. The derived bending equation is coupled with the pressure equation and it contains the bending moment due to the variation in pore pressure across the shell thickness. The effective pressure equation is parabolic only in the normal direction. As additional terms it contains the time derivative of the middle-surface flexural strain. Derivation of the model presents an extension of the results on the derivation of classical linear elastic shells by Ciarlet and collaborators to the poroelastic shells case. The n...
Optimal hedging of Derivatives with transaction costs
Aurell, E; Aurell, Erik; Muratore-Ginanneschi, Paolo
2005-01-01
We investigate the optimal strategy over a finite time horizon for a portfolio of stock and bond and a derivative in an multiplicative Markovian market model with transaction costs (friction). The optimization problem is solved by a Hamilton-Bellman-Jacobi equation, which by the verification theorem has well-behaved solutions if certain conditions on a potential are satisfied. In the case at hand, these conditions simply imply arbitrage-free ("Black-Scholes") pricing of the derivative. While pricing is hence not changed by friction allow a portfolio to fluctuate around a delta hedge. In the limit of weak friction, we determine the optimal control to essentially be of two parts: a strong control, which tries to bring the stock-and-derivative portfolio towards a Black-Scholes delta hedge; and a weak control, which moves the portfolio by adding or subtracting a Black-Scholes hedge. For simplicity we assume growth-optimal investment criteria and quadratic friction.
Derivatives on the isotropic tensor functions
Institute of Scientific and Technical Information of China (English)
DUI Guansuo; WANG Zhengdao; JIN Ming
2006-01-01
The derivative of the isotropic tensor function plays an important part in continuum mechanics and computational mechanics, and also it is still an opening problem. By means of a scalar response function and solving a tensor equation, this problem is well studied. A compact explicit expression for the derivative of the isotropic tensor function is presented, which is valid for both distinct and repeated eigenvalue cases. Throughout the analysis, the formulation holds for general isotropic tensor functions without need to solve eigenvector problems or determine coefficients. On the theoretical side, a very simple solution of a tensor equation is obtained. As an application to continuum mechanics, a base-free expression for the Hill's strain rate is given, which is more compact than the existent results. Finally, with an example we compute the derivative of an exponent tensor function. And the efficiency of the present formulations is demonstrated.
Semisynthetic Derivatives of Epothilones
Altmann, Karl-Heinz
Semisynthetic derivatives of natural products traditionally occupy a prominent space in natural-product-based drug discovery (1, 2). As many biologically active natural products exhibit a high degree of structural complexity (3), the chemical derivatization of material isolated from natural sources often represents the only feasible means (or at least the only economically viable approach) to explore structure-activity-relationships (SAR) and to produce analogs with more favorable pharmacokinetic and pharmacological properties than the natural product lead. Examples of clinically important drugs that are semisynthetic derivatives of natural products exist in virtually all disease areas (1, 2); in the treatment of cancer this includes compounds such as etoposide or teniposide (derived from podophyllotoxin) (4-6), irinotecan and topotecan (derived from camptothecin) (7-9), or docetaxel (derived from 10-deacetylbaccatin III) (10, 11). Even for taxol (11), which is a natural product (12), the sustained supply of sufficient quantities of material for widespread clinical use could only be secured through the development of a semisynthetic production process from another natural product, namely, 10-deacetylbaccatin III (13). In light of these facts, it is not surprising that semisynthesis approaches have also featured prominently in the elucidation of the SAR for epothilones and in the discovery of a number of clinical development candidates.
Lublinsky, Boris; Yakubovich, Alexey
2013-01-01
The go-to guidebook for deploying Big Data solutions with Hadoop Today's enterprise architects need to understand how the Hadoop frameworks and APIs fit together, and how they can be integrated to deliver real-world solutions. This book is a practical, detailed guide to building and implementing those solutions, with code-level instruction in the popular Wrox tradition. It covers storing data with HDFS and Hbase, processing data with MapReduce, and automating data processing with Oozie. Hadoop security, running Hadoop with Amazon Web Services, best practices, and automating Hadoop processes i
Seepold, Ralf E D; Madrid, Natividad Martinez
2011-01-01
Embedded systems have an increasing importance in our everyday lives. The growing complexity of embedded systems and the emerging trend to interconnections between them lead to new challenges. Intelligent solutions are necessary to overcome these challenges and to provide reliable and secure systems to the customer under a strict time and financial budget. ""Solutions on Embedded Systems"" documents results of several innovative approaches that provide intelligent solutions in embedded systems. The objective is to present mature approaches, to provide detailed information on the implementation
Dissipative cosmological solutions
Chimento, Luis P.; Jakubi, Alejandro S.
1997-01-01
The exact general solution to the Einstein equations in a homogeneous Universe with a full causal viscous fluid source for the bulk viscosity index $m=1/2$ is found. We have investigated the asymptotic stability of Friedmann and de Sitter solutions, the former is stable for $m\\ge 1/2$ and the latter for $m\\le 1/2$. The comparison with results of the truncated theory is made. For $m=1/2$, it was found that families of solutions with extrema no longer remain in the full case, and they are repla...
Fractional Derivative Analysis of Helmholtz and Paraxial-Wave Equations
Turski, A J; Turska, E
2002-01-01
Fundamental rules and definitions of Fractional Differintegrals are outlined. Factorizing 1-D and 2-D Helmholtz equations four fractional eigenfunctions are determined. The functions exhibit incident and reflected plane waves as well as diffracted incident and reflected waves of the half-plane edge. They allow to construct the Sommerfeld half-plane diffraction solutions. Parabolic-Wave Equation (PWE, Leontovich-Fock) for paraxial propagation is factorized and differetial fractional solutions of Fresnel-integral type are derived. We arrived at two solutions, which are the mothers of known and new solutions.
Solution to enterprise resource planning; ERP solution
Energy Technology Data Exchange (ETDEWEB)
Suzuki, M.; Okajima, E. [Fuji Electric Co. Ltd., Tokyo (Japan)
2000-05-10
The environment around enterprises has greatly changed in sluggish Japanese economy since the bubble burst. To make the total enterprise activity efficient and speedy and to flexibly meet changes in enterprise environments and diversified customer needs, enterprises are planning to shift the existing methods to enterprise resource planning (ERP) as the infrastructure of strategic enterprise management. This paper describes the solution to ERP which is package software for the key system, the core of enterprise basic business, and also an application example, giving guideline for restructuring the basic business. (author)
Directory of Open Access Journals (Sweden)
Shi-Fang Yuan
2014-01-01
Full Text Available Using the Kronecker product of matrices, the Moore-Penrose generalized inverse, and the complex representation of quaternion matrices, we derive the expressions of least squares solution with the least norm, least squares pure imaginary solution with the least norm, and least squares real solution with the least norm of the quaternion matrix equation AXB+CXD=E, respectively.
Institute of Scientific and Technical Information of China (English)
无
2005-01-01
By using the further extended tanh method [Phys. Lett. A 307 (2003) 269; Chaos, Solitons & Fractals 17(2003) 669] to the Broer-Kaup system with variable coefficients, abundant new soliton-like solutions and multi-soliton-like solutions are derived. Based on the derived multi-soliton-like solutions which contain arbitrary functions, some interesting multi-soliton structures are revealed.
DEFF Research Database (Denmark)
Holm, Henrik Granau
2004-01-01
Over any associative ring R it is standard to derive HomR(;) using projective resolutions in the rst variable, or injective resolutions in the second variable, and doing this, one obtains Extn R(;) in both cases. We examine the situation where projective an...... injective modules are replaced by Gorenstein projective and Gorenstein injective ones, respectively. Furthermore, we derive the tensor product R using Gorenstein at modules.......Over any associative ring R it is standard to derive HomR(;) using projective resolutions in the rst variable, or injective resolutions in the second variable, and doing this, one obtains Extn R(;) in both cases. We examine the situation where projective and...
DEFF Research Database (Denmark)
Kokholm, Thomas
financial models, and most importantly, to be aware of their limitations. Following that belief, this thesis consists of three independent and self-contained papers, all dealing with topics in derivatives pricing. The first paper considers the pricing of traffic light options, which are appropriate...... the market for multivariate credit instruments, we take a step back and focus on single-name default modeling and introduce two new model classes for modeling of the default time of a company. Finally, in the third paper we propose a consistent pricing model for index and volatility derivatives. With...... the existence of a liquid market for derivatives with variance as underlying, such as VIX options, VIX futures and a well-developed over-the-counter market for options on variance swaps, it is important to consider models that are able to fit these markets while consistently pricing vanilla options on...
Asia Pacific energy derivatives
International Nuclear Information System (INIS)
Asia Pacific Energy Derivatives, from FT Energy, is the first report of its kind to examine the growth of energy derivatives within Asia Pacific and their increasing importance within this region. It provides a comprehensive overview of the subject, including analysis of: deregulation as a market driver; the impact of privatisation; the future for energy risk management tools; the unique characteristics of the Asia Pacific energy market; the role of futures exchanges in Asia; existing indexes and their performance; the differences between the Asia Pacific markets and their more mature counterparts in London and New York; non-oil derivatives, project finance and cross commodity arbitrage; the thriving Pacific Rim Over the Counter (OTC) markets. (author)
Analytic Solutions of Elastic Tunneling Problems
Strack, O.E.
2002-01-01
The complex variable method for solving two dimensional linearly elastic problems is used to obtain several fundamental analytical solutions of tunneling problems. The method is used to derive the general mathematical representation of problems involving resultant forces on holes in a half-plane. Such problems are encountered in geomechanics during the excavation of tunnels. When tunnels are excavated the removal of the weighted material inside the tunnel causes the ground under the tunnel to...
Semantic Solutions to Program Analysis Problems
Tobin-Hochstadt, Sam
2011-01-01
Problems in program analysis can be solved by developing novel program semantics and deriving abstractions conventionally. For over thirty years, higher-order program analysis has been sold as a hard problem. Its solutions have required ingenuity and complex models of approximation. We claim that this difficulty is due to premature focus on abstraction and propose a new approach that emphasizes semantics. Its simplicity enables new analyses that are beyond the current state of the art.
Exact Solutions of One-Dimensional TGV
Pöschl, Christiane; Scherzer, Otmar
2013-01-01
L2-TGV-regularization has been introduced by Bredies, Kunisch, and Pock. This regularization method requires careful tuning of two regularization parameters. The focus of this paper is to derive analytical results, which allow for characterizing parameter settings, which make this method in fact different from L2-TV (the ROF-model) and L2-TV2 regularization, respectively. In this paper we also provide explicit solutions of TGV-denoising for particular one-dimensional function data.
A dyadic solution of relative pose problems
Bradley, Patrick Erik
2009-01-01
A hierarchical interval subdivision is shown to lead to a $p$-adic encoding of image data. This allows in the case of the relative pose problem in computer vision and photogrammetry to derive equations having 2-adic numbers as coefficients, and to use Hensel's lifting method to their solution. This method is applied to the linear and non-linear equations coming from eight, seven or five point correspondences. An inherent property of the method is its robustness.
Global Slim Accretion Disk Solutions Revisited
Jiao, Cheng-Liang; Xue, Li; Gu, Wei-Min; Lu, Ju-Fu
2008-01-01
We show that there exists a maximal possible accretion rate, beyond which global slim disk solutions cannot be constructed because in the vertical direction the gravitational force would be unable to balance the pressure force to gather the accreted matter. The principle for this restriction is the same as that for the Eddington luminosity and the corresponding critical accretion rate, which were derived for spherical accretion by considering the same force balance in the radial direction. If...
Coopetitive game solutions for the eurozone economy
Carfì, D.; Magaudda, M.; Schilirò, D.
2010-01-01
This paper aims at providing, through a game theory model of coopetition, feasible solutions in a cooperative perspective to the problems that affect the Eurozone economy after the Greek crisis. In particular, it focuses on stability and growth as the primary goals, which should drive the Eurozone economy in consequence of the financial and economic crisis of the Greek economy with its effects throughout the Euro area. By means of two coopetitive models derived by an original general analytic...
Convergent Aeronautics Solutions Project
National Aeronautics and Space Administration — The Convergent Aeronautics Solutions (CAS) Project uses short-duration activities to establish early-stage concept and technology feasibility for high-potential...
Cromolyn Sodium Nasal Solution
... is sometimes prescribed for other uses; ask your doctor or pharmacist for more information. ... the instructions provided with the solution. Ask your doctor, pharmacist, or respiratory therapist to demonstrate the proper technique. ...
Skenderis, Kostas
2007-01-01
We present a comprehensive analysis of holography for the bubbling solutions of Lin-Lunin-Maladacena. These solutions are uniquely determined by a coloring of a 2-plane, which was argued to correspond to the phase space of free fermions. We show that in general this phase space distribution does not determine fully the 1/2 BPS state of N=4 SYM that the gravitational solution is dual to, but it does determine it enough so that vevs of all single trace 1/2 BPS operators in that state are uniquely determined to leading order in the large N limit. These are precisely the vevs encoded in the asymptotics of the LLM solutions. We extract these vevs for operators up to dimension 4 using holographic renormalization and KK holography and show exact agreement with the field theory expressions.
TUTUNEA MIHAELA FILOFTEIA
2012-01-01
The integration of activities, the business processes as well as their optimization, bring the perspective of profitable growth and create significant and competitive advantages in any company. The adoption of some ERP integrated software solutions, from SMEs’ perspective, must be considered as a very important management decision in medium and long term. ERP solutions, along with the transparent and optimized management of all internal processes, also offer an...
Improving Energy Efficiency in Industrial Solutions – Walk the Talk
DEFF Research Database (Denmark)
Wegener, Dieter; Finkbeiner, Matthias; Holst, Jens-Christian;
2011-01-01
This paper describes the outline of the energy efficiency and environmental care policy and management at Siemens Industry Solutions Division. This environmental policy coherently embraces strategic planning, eco-design of energy-efficient industrial processes and solutions, design evaluation and...... finally communication of both environmental and economic performance of solutions to customers. One of the main tools supporting eco-design and evaluation & controlling of derived design solutions is the so called “Eco-Care-Matrix” (ECM). The ECM simply visualizes the eco-efficiency of solutions compared...... describes the economical customer benefit of one or more green solutions compared to a defined reference solution. Different scientific approaches for quantifying the environmental performance based on life cycle assessment methodology are discussed especially considering the ISO standards 14040...
Conduction heat transfer solutions
International Nuclear Information System (INIS)
This text is a collection of solutions to a variety of heat conduction problems found in numerous publications, such as textbooks, handbooks, journals, reports, etc. Its purpose is to assemble these solutions into one source that can facilitate the search for a particular problem solution. Generally, it is intended to be a handbook on the subject of heat conduction. There are twelve sections of solutions which correspond with the class of problems found in each. Geometry, state, boundary conditions, and other categories are used to classify the problems. Each problem is concisely described by geometry and condition statements, and many times a descriptive sketch is also included. The introduction presents a synopsis on the theory, differential equations, and boundary conditions for conduction heat transfer. Some discussion is given on the use and interpretation of solutions. Supplementary data such as mathematical functions, convection correlations, and thermal properties are included for aiding the user in computing numerical values from the solutions. 155 figs., 92 refs., 9 tabs
Fundamental solutions for isotropic size-dependent couple stress elasticity
Hadjesfandiari, Ali R
2011-01-01
Fundamental solutions for two- and three-dimensional linear isotropic size-dependent couple stress elasticity are derived, based upon the decomposition of displacement fields into dilatational and solenoidal components. While several fundamental solutions have appeared previously in the literature, the present version is for the newly developed fully determinate couple stress theory. Within this theory, the couple stress tensor is skewsymmetrical and thus possesses vectorial character. The present derivation provides solutions for infinite domains of elastic materials under the influence of unit concentrated forces and couples. Unlike all previous work, unique solutions for displacements, rotations, force-stresses and couple-stresses are established, along with the corresponding force-tractions and couple-tractions. These fundamental solutions are central in analysis methods based on Green's functions for infinite domains and are required as kernels in the corresponding boundary integral formulations for size...
Comment on: ‘Peakon and solitonic solutions for KdV-like equations’
Leite Freire, Igor
2016-04-01
In a recent paper (Wazwaz 2015 Phys. Scr. 90 045203) some evolution equations were considered. Among other results, it found peakon solutions for the equations under consideration. This sort of solution corresponds to weak solutions, piecewise smooth, with no derivative in a certain point, the peaks. In this note we show that the weak functions claimed as solutions are not solutions for at least two of the equations investigated.
Solutions of the U(N)σ models with the Wess-Zumino term
International Nuclear Information System (INIS)
We study finite action classical solutions of the Euclidean two-dimensional U(N) sigma models with the Wess-Zumino term. We show that these solutions are related to (and so can be derived from) the solutions of the Lax-pair problem for the corresponding U(N) sigma model (without the Wess-Zumino term). We discuss the value of the action for these solutions and prove that all these solutions are unstable. (orig.)
Smyrnakis, J.; Magiropoulos, M.; Kavoulakis, G. M.; Jackson, A. D.
2013-01-01
We derive solitary-wave solutions within the mean-field approximation in quasi-one-dimensional binary mixtures of Bose-Einstein condensates under periodic boundary conditions, for the case of an effective repulsive interatomic interaction. The particular gray-bright solutions that give the global energy minima are determined. Their characteristics and the associated dispersion relation are derived.
"Closed-form Solution of Bond Prices with Postponement of Redemption"(in Japanese)
Ryoichi Ikeda; Takao Kobayashi
2007-01-01
This paper shows the analytical solution of a bond price with postponement of redemption by considering the special case of Ikeda and Kobayashi (2007). We can derive the solution by solving a Wiener-Hopf type integral equation, and such derivation does not have an example in others. Therefore the further development will be expected in various financial analyses.
Closed-form Solution of Bond Prices with Postponement of Redemption
Ryoichi Ikeda; Takao Kobayashi
2007-01-01
This paper shows the analytical solution of a bond price with postponement of redemption by considering the special case of Ikeda and Kobayashi (2007). We can derive the solution by solving a Wiener-Hopf type integral equation, and such derivation does not have an example in others. Therefore the further development will be expected in various financial analyses.
Iterative solution of Hermite boundary integral equations
Energy Technology Data Exchange (ETDEWEB)
Gray, Leonard J [ORNL; Nintcheu Fata, Sylvain [ORNL; Ma, Ding [ORNL
2008-01-01
An efficient iterative method for the solution of the linear equations arising from a Hermite boundary integral approximation has been developed. Along with equations for the boundary unknowns, the Hermite system incorporates equations for the first-order surface derivatives (gradient) of the potential, and is therefore substantially larger than the matrix for a corresponding linear approximation. However, by exploiting the structure of the Hermite matrix, a two-level iterative algorithm has been shown to provide a very efficient solution algorithm. In this approach, the boundary function unknowns are treated separately from the gradient, taking advantage of the sparsity and near-positive definiteness of the gradient equations. In test problems, the new algorithm significantly reduced computation time compared to iterative solution applied to the full matrix. This approach should prove to be even more effective for the larger systems encountered in three-dimensional analysis, and increased efficiency should come from pre-conditioning of the non-sparse matrix component.
Integer Solutions of a Special Diophantine Equation
Özkoç, Arzu; Tekcan, Ahmet
2011-09-01
Let t≠1 be an integer. In this work, we determine the integer solutions of Diophantine equation D:x2+(2-t2)y2+(-2t2-2t+2)x+(2t5-6t3+4t)y-t8+4t6-4t4+2t3+t2-2t = 0 over Z and also over finite fields Fp for primes p≥2. Also we derive some recurrence relations on the integer solutions (xn,yn) of D and formulate the the n—th solution (xn,yn) by using the simple continued fraction expansion of xn/yn.
Solute transport through a deforming porous medium
Peters, Glen P.; Smith, David W.
2002-06-01
Solute transport through a porous medium is typically modelled assuming the porous medium is rigid. However, many applications exist where the porous medium is deforming, including, municipal landfill liners, mine tailings dams, and land subsidence. In this paper, mass balance laws are used to derive the flow and transport equations for a deforming porous medium. The equations are derived in both spatial and material co-ordinate systems. Solute transport through an engineered landfill liner is used as an illustrative example to show the differences between the theory for a rigid porous medium, and small and large deformation analysis of a deforming porous medium. It is found that the large deformation model produces shorter solute breakthrough times, followed by the small deformation model, and then the rigid porous medium model. It is also found that it is important to include spatial and temporal void ratio variations in the large deformation analysis. It is shown that a non-linear large deformation model may greatly reduce the solute breakthrough time, compared to a standard transport analysis typically employed by environmental engineers.
Metal derivatives of tetrazoles
International Nuclear Information System (INIS)
Published data on the synthesis, structure, properties and applications of metal derivatives of tetrazoles are generalised and described systematically. Compounds based on the anionic and neutral tetrazole forms, C- and N-mono- and C,N-disubstituted tetrazoles are considered.
Metal derivatives of tetrazoles
Energy Technology Data Exchange (ETDEWEB)
Gaponik, Pavel N; Voitekhovich, Sergei V; Ivashkevich, Oleg A [Research Institute for Physical Chemical Problems of the Belarusian State University, Minsk (Belarus)
2006-06-30
Published data on the synthesis, structure, properties and applications of metal derivatives of tetrazoles are generalised and described systematically. Compounds based on the anionic and neutral tetrazole forms, C- and N-mono- and C,N-disubstituted tetrazoles are considered.
Biotechnology and derived products
Microorganisms able to infect and kill insect pests, metabolites from plants and microorganisms, and transgenic crops are biotechnologically derived products that are being promoted for use to control insect pests in lieu of chemical insecticides. Products based on these technologies effectively co...
Learning, investments and derivatives
Soklakov, Andrei N.
2011-01-01
The recent crisis and the following flight to simplicity put most derivative businesses around the world under considerable pressure. We argue that the traditional modeling techniques must be extended to include product design. We propose a quantitative framework for creating products which meet the challenge of being optimal from the investors point of view while remaining relatively simple and transparent.
O. Emre Ergungor
2007-01-01
Until recently, homeowners had no way to protect the value of their homes against losses that could result from housing market downturns. With the derivatives contracts introduced by the CME last year, homeowners now have some means of protection, and new and better products are more likely to follow from them.
Oxygenated Derivatives of Hydrocarbons
For the book entitled “Insect Hydrocarbons: Biology, Biochemistry and Chemical Ecology”, this chapter presents a comprehensive review of the occurrence, structure and function of oxygenated derivatives of hydrocarbons. The book chapter focuses on the occurrence, structural identification and functi...
Derivative corrections from noncommutativity
International Nuclear Information System (INIS)
We show that an infinite subset of the higher-derivative α' corrections to the DBI and Chern-Simons actions of ordinary commutative open-string theory can be determined using noncommutativity. Our predictions are compared to some lowest order α' corrections that have been computed explicitly by Wyllard (hep-th/0008125), and shown to agree. (author)
On the solution of fractional evolution equations
Energy Technology Data Exchange (ETDEWEB)
Kilbas, Anatoly A [Department of Mathematics and Mechanics, Belarusian State University, 220050 Minsk (Belarus); Pierantozzi, Teresa [Departamento de Matematica Aplicada, Facultad de Informatica, Universidad Complutense, E-28040 Madrid (Spain); Trujillo, Juan J [Departamento de Analisis Matematico, Universidad de la Laguna, 38271 La Laguna-Tenerife (Spain); Vazquez, Luis [Departamento de Matematica Aplicada, Facultad de Informatica, Universidad Complutense, E-28040 Madrid (Spain)
2004-03-05
This paper is devoted to the solution of the bi-fractional differential equation ({sup C}D{sup {alpha}}{sub t}u)(t, x) = {lambda}({sup L}D{sup {beta}}{sub x}u)(t, x) (t>0, -{infinity}
The tripole vortex: Experimental evidence and explicit solutions.
Kizner, Ziv; Khvoles, Ruvim
2004-01-01
Based on experimental evidence, explicit vorticity-distributed solutions to the Euler equations in two dimensions are constructed describing the tripole vortex. The vortex form and the solution outside the region of nonzero vorticity are derived analytically, while the interior is solved numerically. The continuous-vorticity solution reproduces the main features of the tripoles observed in laboratory experiments and numerical simulations-their shape, flow pattern, and the form of the nonlinear vorticity vs streamfunction relation. The approach followed in the construction of a tripole proves to be beneficial in the search for higher-order multipoles, an example being a smooth quadrupole solution. PMID:15324169
The tripole vortex: Experimental evidence and explicit solutions
International Nuclear Information System (INIS)
Based on experimental evidence, explicit vorticity-distributed solutions to the Euler equations in two dimensions are constructed describing the tripole vortex. The vortex form and the solution outside the region of nonzero vorticity are derived analytically, while the interior is solved numerically. The continuous-vorticity solution reproduces the main features of the tripoles observed in laboratory experiments and numerical simulations - their shape, flow pattern, and the form of the nonlinear vorticity vs streamfunction relation. The approach followed in the construction of a tripole proves to be beneficial in the search for higher-order multipoles, an example being a smooth quadrupole solution
Energy Technology Data Exchange (ETDEWEB)
Strom, I.; Joosten, L.; Boonstra, C. [DHV Sustainability Consultants, Eindhoiven (Netherlands)
2006-05-15
PEP stands for 'Promotion of European Passive Houses' and is a consortium of European partners, supported by the European Commission, Directorate General for Energy and Transport. In this working paper an overview is given of Passive House solutions. An inventory has been made of Passive House solutions for new build residences applied in each country. Based on this, the most common basic solutions have been identified and described in further detail, including the extent to which solutions are applied in common and best practice and expected barriers for the implementation in each country. An inventory per country is included in the appendix. The analysis of Passive House solutions in partner countries shows high priority with regard to the performance of the thermal envelope, such as high insulation of walls, roofs, floors and windows/ doors, thermal bridge-free construction and air tightness. Due to the required air tightness, special attention must be paid to indoor air quality through proper ventilation. Finally, efficient ((semi-)solar) heating systems for combined space and DHW heating still require a significant amount of attention in most partner countries. Other basic Passive House solutions show a smaller discrepancy with common practice and fewer barriers have been encountered in partner countries. In the next section, the general barriers in partner countries have been inventoried. For each type of barrier a suggested approach has been given. Most frequently encountered barriers in partner countries are: limited know-how; limited contractor skills; and acceptation of Passive Houses in the market. Based on the suggested approaches to overcoming barriers, this means that a great deal of attention must be paid to providing practical information and solutions to building professionals, providing practical training to installers and contractors and communication about the Passive House concept to the market.
New Electrically Charged Black Hole in Higher Derivative Gravity as Particle Colliders
Lin, Kai; Pavan, A. B.; Flores-Hidalgo, G.; Abdalla, E.
2016-01-01
In this paper, new electrically charged asymptotically flat black hole solutions are numerically derived in the context of higher derivative gravity. These solutions can be interpreted as generalizations of two different classes of non-charged asymptotically flat spacetimes: Schwarzschild and non-Schwarzschild solutions. The possibility to use these black holes as particle colliders have been analysed. Our results show that the center-of-mass energy of two accelerated charged particles could ...
Analysis of the Error Associated With the Domenico Solution
Srinivasan, V.; Clement, T.; Lee, K.
2006-12-01
The Domenico solution is one of the widely used analytical solutions used in screening-level ground water contaminant transport models; e.g., BIOCHLOR and BIOSCREEN. This approximate solution describes the transport of a decaying contaminant subjected to advection in one dimension and dispersion in all three dimensions. However, the development of this solution as presented by the original authors involves approximations that are more heuristic than rigorous. This makes it difficult to predict the nature of the error associated with these approximations. Hence, several ground water modelers have expressed skepticism regarding the validity of this solution. To address the issues stated above, it is necessary to perform a rigorous mathematical analysis on the Domenico solution. In this work a rigorous mathematical approach to derive the Domenico solution is presented. Furthermore, the limits of this approximation are explored to provide a qualitative assessment of the error associated with the Domenico solution. The analysis indicates that the Domenico solution is an exact analytical solution when the value of the longitudinal dispersivity is zero. For all non-zero longitudinal dispersivity values, the Domenico solution will have a finite error. The results of our analysis also indicate that this error is highly sensitive to the value of the longitudinal dispersivity and the position of the advective front. Based on these inferences some general guidelines for the appropriate use of this solution are suggested.
The Optimality of Satisficing Solutions
Hansson, Othar; Mayer, Andy
2013-01-01
This paper addresses a prevailing assumption in single-agent heuristic search theory- that problem-solving algorithms should guarantee shortest-path solutions, which are typically called optimal. Optimality implies a metric for judging solution quality, where the optimal solution is the solution with the highest quality. When path-length is the metric, we will distinguish such solutions as p-optimal.
Towards combined global monthly gravity field solutions
Jaeggi, Adrian; Meyer, Ulrich; Beutler, Gerhard; Weigelt, Matthias; van Dam, Tonie; Mayer-Gürr, Torsten; Flury, Jakob; Flechtner, Frank; Dahle, Christoph; Lemoine, Jean-Michel; Bruinsma, Sean
2014-05-01
Currently, official GRACE Science Data System (SDS) monthly gravity field solutions are generated independently by the Centre for Space Research (CSR) and the German Research Centre for Geosciences (GFZ). Additional GRACE SDS monthly fields are provided by the Jet Propulsion Laboratory (JPL) for validation and outside the SDS by a number of other institutions worldwide. Although the adopted background models and processing standards have been harmonized more and more by the various processing centers during the past years, notable differences still exist and the users are more or less left alone with a decision which model to choose for their individual applications. This procedure seriously limits the accessibility of these valuable data. Combinations are well established in the area of other space geodetic techniques, such as the Global Navigation Satellite Systems (GNSS), Satellite Laser Ranging (SLR), and Very Long Baseline Interferometry (VLBI). Regularly comparing and combining space-geodetic products has tremendously increased the usefulness of the products in a wide range of disciplines and scientific applications. Therefore, we propose in a first step to mutually compare the large variety of available monthly GRACE gravity field solutions, e.g., by assessing the signal content over selected regions, by estimating the noise over the oceans, and by performing significance tests. We make the attempt to assign different solution characteristics to different processing strategies in order to identify subsets of solutions, which are based on similar processing strategies. Using these subsets we will in a second step explore ways to generate combined solutions, e.g., based on a weighted average of the individual solutions using empirical weights derived from pair-wise comparisons. We will also assess the quality of such a combined solution and discuss the potential benefits for the GRACE and GRACE-FO user community, but also address minimum processing
Approximate *-derivations and approximate quadratic *-derivations on C*-algebras
Directory of Open Access Journals (Sweden)
Park Choonkil
2011-01-01
Full Text Available Abstract In this paper, we prove the stability of *-derivations and of quadratic *-derivations on Banach *-algebras. We moreover prove the superstability of *-derivations and of quadratic *-derivations on C*-algebras. 2000 Mathematics Subject Classification: 39B52; 47B47; 46L05; 39B72.
International Nuclear Information System (INIS)
Using the Green function techniques, the wave solutions were expressed of the radial inhomogeneous Schroedinger equation by means of the on-shell Jost and regular solutions. Using their boundary behaviour at r = infinity and r = 0, the wave solutions were re-expressed alternatively in terms of the off-shell Jost and regular solutions. Relations among the different generalized (fully off the energy shell) Jost functions are derived and the radial matrix elements of the transition and reaction (reactance) operators are given in terms of these Jost functions. The relations reflect the principle of detailed balance. (author)
On alpha'-corrections to D-brane solutions
De Haro, S; Skenderis, K; Haro, Sebastian de; Sinkovics, Annamaria; Skenderis, Kostas
2003-01-01
We discuss the computation of the leading corrections to D-brane solutions due to higher derivative terms in the corresponding low energy effective action. We develop several alternative methods for analyzing the problem. In particular, we derive an effective one-dimensional action from which the field equations for spherically symmetric two-block brane solutions can be derived, show how to obtain first order equations, and discuss a few other approaches. We integrate the equations for extremal branes and obtain the corrections in terms of integrals of the evaluation of the higher derivative terms on the lowest order solution. To obtain completely explicit results one would need to know all leading higher derivative corrections which at present are not available. One of the known higher derivative terms is the R^4 term, and we obtain the corrections to the D3 brane solution due to this term alone. We note, however, that (unknown at present) higher terms depending on F_5 are expected to modify our result. We a...
Institute of Scientific and Technical Information of China (English)
ZHU Qiding; MENG Lingxiong
2004-01-01
In this paper the ultraconvergence of the derivative for odd-degree rectangular elements is addressed. A new, discrete least-squares patch recovery technique is proposed to post-process the solution derivatives. Such recovered derivatives are shown to possess ultraconvergence by using projection type interpolation.
International Nuclear Information System (INIS)
This paper deals with in situ solution mining. A significant fraction of known U.S. uranium reserves occur as low grade mineralization in sedimentary sandstone deposits located between 40 and 200 meters subsurface. For a variety of reasons, such deposits may not be economically developable by any method other than in situ solution mining. This coupled with the current market price of uranium has led to significant development and application of in situ solution mining for uranium production during the past several years. The process consists of the ore body; well field; lixiviant; uranium recovery process; waste treatment processes; and aquifer restoration. A tabulation of firms involved with a summary of the leach chemistry used is given. 3 refs
International Nuclear Information System (INIS)
In this note we construct families of asymptotically flat, smooth, horizonless solutions with a large number of non-trivial two-cycles (bubbles) of N = 1 five-dimensional supergravity with an arbitrary number of vector multiplets, which may or may not have the charges of a macroscopic black hole and which contain the known bubbling solutions as a sub-family. We do this by lifting various multi-center BPS states of type IIA compactified on Calabi-Yau three-folds and taking the decompactification (M-theory) limit. We also analyse various properties of these solutions, including the conserved charges, the shape, especially the (absence of) throat and closed timelike curves, and relate them to the various properties of the four-dimensional BPS states. We finish by briefly commenting on their degeneracies and their possible relations to the fuzzball proposal of Mathur et al
Systems of integrable derivations
Directory of Open Access Journals (Sweden)
Vittoria Bonanzinga
1994-05-01
Full Text Available Let A be a commutative k-algebra, with k a subring of A. We give the definition of n-dimensional differentiation of A over k which formally extends the known one of unidimensional differentiation and we study the group of all n-dimensional differentiation of A over k. In the second part of the work we give some theorems of strong integrability for systems of derivations in terms of n-dimensional differentiation.
Illiquidity and derivative valuation
Horst, Ulrich; Naujokat, Felix
2010-01-01
In illiquid markets, option traders may have an incentive to increase their portfolio value by using their impact on the dynamics of the underlying. We provide a mathematical framework within which to value derivatives under market impact in a multi-player framework by introducing strategic interactions into the model of Almgren and Chriss (2001). Specifically, we consider a financial market model with several strategically interacting players that hold European contingent claims and whose tr...
Energy Technology Data Exchange (ETDEWEB)
Bulatov, A.I.; Arakelyan, A.A.; Gen' , O.U.; Krutikova, N.I.; Lezhenin, V.V.; Repyakhova, T.M.; Rudomino, M.V.; Ryabova, L.I.
1983-01-01
The purpose of this invention is to increase the setting time of a binder at temperatures between 200 and 300 degrees centigrade, to reduce the water loss of the solution and to improve the strength of the plugging rock. This is achieved by an arrangement whereby the plugging solution consisting of a binder, water and an organic element setting retarder contains mononuclear complexones of nitryltrimethylphosphonic acid for use as the setting retarder, with the following component ratios (percentage by weight): binder 70.71 to 72.80; organic component setting retarder .0072 to 1; water the remaining.
Jorgensen, Adam; Welch, John; Clark, Dan; Price, Christopher; Mitchell, Brian
2014-01-01
Tap the power of Big Data with Microsoft technologies Big Data is here, and Microsoft's new Big Data platform is a valuable tool to help your company get the very most out of it. This timely book shows you how to use HDInsight along with HortonWorks Data Platform for Windows to store, manage, analyze, and share Big Data throughout the enterprise. Focusing primarily on Microsoft and HortonWorks technologies but also covering open source tools, Microsoft Big Data Solutions explains best practices, covers on-premises and cloud-based solutions, and features valuable case studies. Best of all,
Amiano, Mitch; Ethier, Kay; Thomas, Michael D
2006-01-01
Offering a unique approach to learning XML, this book walks readers through the process of building a complete, functional, end-to-end XML solutionFeatured case study is an online business product catalog that includes reports, data input/output, workflow, stylesheet formatting, RSS feeds, and integration with external services like Google, eBay, and AmazonThe format of presenting a problem and working through the design to come up with a solution enables readers to understand how XML markup allows a business to share data across applications internally or with partners or customers even thoug
DEFF Research Database (Denmark)
Ørding Olsen, Anders
when pursuing minor performance improvements in existing technologies. However, reliance on internal knowledge sources carries a risk of organizational inertia related to problem understanding and solution development in the shape of path-dependencies and preferences for exploitation and reapplication...... of existing knowledge. Such inertia may imbue innovation processes related to the development of new technologies with reduced novelty and an inability to recognize alternative and potentially more attractive solutions. As a result, over-reliance on internal knowledge sources is likely to inhibit the...
Calculus problems and solutions
Ginzburg, A
2011-01-01
Ideal for self-instruction as well as for classroom use, this text helps students improve their understanding and problem-solving skills in analysis, analytic geometry, and higher algebra. More than 1,200 problems appear in the text, with concise explanations of the basic notions and theorems to be used in their solution. Many are followed by complete answers; solutions for the others appear at the end of the book. Topics include sequences, functions of a single variable, limit of a function, differential calculus for functions of a single variable, fundamental theorems and applications of dif
Endostatin derivative angiogenesis inhibitors
Institute of Scientific and Technical Information of China (English)
ZHENG Meng-jie
2009-01-01
Objective To throw light on the superiority of the anti-angiogenesis activity of endostatin (ES) derivatives by reviewing the recent progress in the field of ES molecular structure modification.Data sources The data used in this article were mainly from PubMed with relevant English articles published from 1971 to May 2008.The search terms were "endostatin" and "angiothesis".Study selection Articles involved in the ES molecular structure modification and the original milestone articles were selected.Results A number of ES derivatives were designed and studied to improve its clinical relevance.The modified ES with polyethylene glycol (PEG),low molecular weight heparin (LMWH) and IgG Fc domain extended the circulation half-life.Meanwhile the recombinant ESs showed more potent anti-tumor activity than native ES in mouse xenografts.Mutated ES also changed its anti-angiogenesis activity.Conclusions The anti-angiogenesis treatment remains a promising tumor therapeutic strategy.New ES derivatives would be a good choice to meet the future challenge on clinical application of ES.
Exact solution for spin precession in the radiationless relativistic Kepler problem
Energy Technology Data Exchange (ETDEWEB)
Mane, S.R., E-mail: srmane001@gmail.com
2014-11-11
There is interest in circulating beams of polarized particles in all-electric storage rings to search for nonzero permanent electric dipole moments of subatomic particles. To this end, it is helpful to derive exact analytical solutions of the spin precession in idealized models, both for pedagogical reasons and to serve as benchmark tests for analysis and design of experiments. This paper derives exact solutions for the spin precession in the relativistic Kepler problem. Some counterintuitive properties of the solutions are pointed out.
Ghanmi, Allal
2011-01-01
We prove that the Folland's fundamental solution for the sub-Laplacian on Heisenberg groups can also be derived form the resolvent kernel of this sub-Laplacian. This provides us with a new integral representation for this fundamental solution.
Solutions of the supersymmetric U(N) /sigma/ models with the Wess-Zumino-Witten term
Energy Technology Data Exchange (ETDEWEB)
Piette, B.; Zait, R.A.; Zakrzewski, W.J.
1989-09-01
We present finite action classical solutions of the supersymmetric (Susy) U(N) sigma models with and without the Wess-Zumino-Witten (WZW) term. We derive solutions of the model with the WZW-term from the solutions of the Lax-pair problem for the corresponding model without this term. We study some properties of these solutions such as the value of their action and show that this value is related to that of the purely bosonic U(N) /sigma/-model. Moreover, we prove that all derived solutions are unstable. (orig.).
Airy asymptotics: the logarithmic derivative and its reciprocal
Energy Technology Data Exchange (ETDEWEB)
Kearney, Michael J [Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, Surrey, GU2 7XH (United Kingdom); Martin, Richard J [AHL, Man Investments Limited, Sugar Quay, Lower Thames Street, London, EC3R 6DU (United Kingdom)], E-mail: m.j.kearney@surrey.ac.uk
2009-10-23
We consider the asymptotic expansion of the logarithmic derivative of the Airy function Ai'(z)/Ai(z), and also its reciprocal Ai(z)/Ai'(z), as |z| {yields} {infinity}. We derive simple, closed-form solutions for the coefficients which appear in these expansions, which are of interest since they are encountered in a wide variety of problems. The solutions are presented as Mellin transforms of given functions; this fact, together with the methods employed, suggests further avenues for research.
Chaotic solutions of(2+1)-dimensional Broek-Kaup equation with variable coefficients
Institute of Scientific and Technical Information of China (English)
Yang Zheng; Ma Song-Hua; Fang Jian-Ping
2011-01-01
In this paper, an improved projective approach is used to obtain the variable separation solutions with two arbitrary functions of the(2+1)-dimensional Broek-Kaup equation with variable coefficients(VCBK). Based on the derived solitary wave solution and using a known chaotic system, some novel chaotic solutions are investigated.
Global solutions to a class of CEC benchmark constrained optimization problems
Zhou, Xiaojun
2012-01-01
This paper aims to solve a class of CEC benchmark constrained optimization problems that have been widely studied by nature-inspired optimization algorithms. Global optimality condition based on canonical duality theory is derived. Integrating the dual solutions with the KKT conditions, we are able to obtain the approximate solutions or global solutions easily.
An analytical solution of non-Fourier Chen-Holmes bioheat transfer equation
Institute of Scientific and Technical Information of China (English)
GOU Chenhua; CAI Ruixian
2005-01-01
An algebraically explicit analytical solution with heat wave effect is derived for the non-Fourier bioheat transfer Chen-Holmes model. Besides its important theoretical meaning (for example, to expand the understanding of heat wave phenomena in living tissues), this analytical solution is also valuable as the benchmark solution to check the numerical calculation and to develop various numerical computational approaches.
New soliton solutions of dissipative (2+1)-dimensional AKNS equation
Mohammad Najafi; Somayeh Najafi; Malihe Najafi
2013-01-01
We employ the idea of Hirota’s bilinear method, to obtain some new exact soliton solutions for high nonlinear form of dissipative (2+1)-dimensional AKNS equation. Multiple singular soliton solutions were obtained by this method. Moreover, multiple singular soliton solutions were also derived.
SEM-EDX STUDIES OF CHITOSAN DERIVATIVES-METAL ADDUCTS
Galo Cárdenas; Edelio Taboada; Armando Bravo; S. Patricia Miranda
2003-01-01
Chitosan was obtained from shrimps shells (pleuroncodes monodon) using chemical methods. A series of chitosan (QS)charged with solution of copper, cobalt, nickel and mercury ions were prepared at room temperature using the batch method. N-3,5-diethylamino benzoyl chitosan (QDAB); N,O-dimercapto succinate chitosan (QNOT) and 4-aminobenzoate chitosan (QAB) derivatives were prepared. The chitosan metal adducts with Cu, Co, Ni and Hg ions and derivatives maximum loading is discussed. Chitosan and...
A classical approach to higher-derivative gravity
International Nuclear Information System (INIS)
Two classical routes towards higher-derivative gravity theory are described. The first one is a geometrical route, starting from first principles. The second route is a formal one, and is based on a recent theorem by Castagnino et.al. [J. Math. Phys. 28 (1987) 1854]. A cosmological solution of the higher-derivative field equations is exhibited which in a classical framework singles out this gravitation theory. (author)
On the pricing and hedging of volatility derivatives
Howison, Sam; Rafailidis, Avraam; Rasmussen, Henrik
2003-01-01
We consider the pricing of a range of volatility derivatives, including volatility and variance swaps and swaptions. Under risk-neutral valuation we provide closed-form formulae for volatility-average and variance swaps for a variety of diffusion and jump-diffusion models for volatility. We describe a general partial differential equation framework for derivatives that have an extra dependence on an average of the volatility. We give approximate solutions of this equation for volatility produ...
Aqueous polyethylene oxide solutions
International Nuclear Information System (INIS)
A number of aspects concerning the reorientation of polymer, water and ion hydration complexes have been studied in aqueous solution of polyethylene oxide (PEO). The polymer dynamics are investigated by 1H-PEO and 13C-PEO nuclear relaxation experiments. 162 refs.; 30 figs.; 19 tabs
DEFF Research Database (Denmark)
Steffansen, Bente; Nielsen, Carsten Uhd; Brodin, Birger; Eriksson, André Huss; Andersen, Rikke; Frokjaer, Sven
2004-01-01
A large amount of absorptive intestinal membrane transporters play an important part in absorption and distribution of several nutrients, drugs and prodrugs. The present paper gives a general overview on intestinal solute carriers as well as on trends and strategies for targeting drugs and...
Glycosylation of solute carriers
DEFF Research Database (Denmark)
Pedersen, Nis Borbye; Carlsson, Michael C; Pedersen, Stine Helene Falsig
2016-01-01
Solute carriers (SLCs) are one of the largest groups of multi-spanning membrane proteins in mammals and include ubiquitously expressed proteins as well as proteins with highly restricted tissue expression. A vast number of studies have addressed the function and organization of SLCs as well as...
School Solutions for Cyberbullying
Sutton, Susan
2009-01-01
This article offers solutions and steps to prevent cyberbullying. Schools can improve their ability to handle cyberbullying by educating staff members, students, and parents and by implementing rules and procedures for how to handle possible incidents. Among the steps is to include a section about cyberbullying and expectations in the student…
Zee, van der S.E.A.T.M.; Leijnse, A.
2013-01-01
Solute transport is of importance in view of the movement of nutrient elements, e.g. towards the plant root system, and because of a broad range of pollutants. Pollution is not necessarily man induced, but may be due to geological or geohydrological causes, e.g. in the cases of pollution with arseni
DEFF Research Database (Denmark)
Chakkol, Mehmet; Johnson, Mark; Raja, Jawwad;
2014-01-01
Purpose – This paper aims to adopt service-dominant logic (SDL) to empirically explore network configurations resulting from the provision of goods, goods and services, and solutions. Design/methodology/approach – This paper uses a single, in-depth, exploratory case study in a truck manufacturer...
Credit derivatives and risk management
Michael S. Gibson
2007-01-01
The striking growth of credit derivatives suggests that market participants find them to be useful tools for risk management. I illustrate the value of credit derivatives with three examples. A commercial bank can use credit derivatives to manage the risk of its loan portfolio. An investment bank can use credit derivatives to manage the risks it incurs when underwriting securities. An investor, such as an insurance company, asset manager, or hedge fund, can use credit derivatives to align its...
Credit derivatives in emerging markets
Ranci??re, Romain
2002-01-01
Credit Derivatives are securities that offer protection against credit or default risk of bonds or loans. The credit derivatives emerging market has grown rapidly and credit derivatives are widely used. This paper describes the emerging credit derivatives market structure. The current market activity is analyzed through elementary pricing dynamics and the study of the term structure of default risk. Focusing on the performance of credit derivatives in stress situation, includin...
Self-aggregation of liquids from biomass in aqueous solution
International Nuclear Information System (INIS)
Highlights: • Aggregation behaviour of liquids from biomass in aqueous solution has been studied. • Standard Gibbs free energies of aggregation have been calculated. • Solubility in water of these compounds has been determined. • Critical aggregation concentration decreases as the solubility in water does. -- Abstract: Aggregation of several chemicals from biomass: furfural derived compounds (furfural, 5-methylfurfural, furfuryl alcohol and tetrahydrofurfuryl alcohol), lactate derived compounds (methyl lactate, ethyl lactate and butyl lactate), acrylate derived compound (methyl acrylate) and levulinate compounds (methyl levulinate, ethyl levulinate and butyl levulinate) in aqueous solution has been characterised at T = 298.15 K through density, ρ, speed of sound, u, and isentropic compressibilities, κS, measurements. In addition the standard Gibbs free energies of aggregation have been also calculated. Furthermore, in order to deepen insight the behaviour of these chemicals in aqueous solution, the solubility of these compounds has been measured at T = 298.15 K
Fundamental solutions of linear partial differential operators theory and practice
Ortner, Norbert
2015-01-01
This monograph provides the theoretical foundations needed for the construction of fundamental solutions and fundamental matrices of (systems of) linear partial differential equations. Many illustrative examples also show techniques for finding such solutions in terms of integrals. Particular attention is given to developing the fundamentals of distribution theory, accompanied by calculations of fundamental solutions. The main part of the book deals with existence theorems and uniqueness criteria, the method of parameter integration, the investigation of quasihyperbolic systems by means of Fourier and Laplace transforms, and the representation of fundamental solutions of homogeneous elliptic operators with the help of Abelian integrals. In addition to rigorous distributional derivations and verifications of fundamental solutions, the book also shows how to construct fundamental solutions (matrices) of many physically relevant operators (systems), in elasticity, thermoelasticity, hexagonal/cubic elastodynamics...
Exact solutions to the double Sine-Gordon equation
International Nuclear Information System (INIS)
The double Sine-Gordon equation (DSG) with arbitrary constant coefficients is studied by F-expansion method, which can be thought of as an over-all generalization of the Jacobi elliptic function expansion since F here stands for every one of the Jacobi elliptic functions (even other functions). We first derive three kinds of the generic solutions of the DSG as well as the generic solutions of the Sine-Gordon equation (SG), then in terms of Appendix A, many exact periodic wave solutions, solitary wave solutions and trigonometric function solutions of the DSG are separated from its generic solutions. The corresponding results of the SG, which is a special case of the DSG, can also be obtained
Analytic solutions of an unclassified artifact /
Energy Technology Data Exchange (ETDEWEB)
Trent, Bruce C.
2012-03-01
This report provides the technical detail for analytic solutions for the inner and outer profiles of the unclassified CMM Test Artifact (LANL Part Number 157Y-700373, 5/03/2001) in terms of radius and polar angle. Furthermore, analytic solutions are derived for the legacy Sheffield measurement hardware, also in terms of radius and polar angle, using part coordinates, i.e., relative to the analytic profile solutions obtained. The purpose of this work is to determine the exact solution for the “cosine correction” term inherent to measurement with the Sheffield hardware. The cosine correction is required in order to interpret the actual measurements taken by the hardware in terms of an actual part definition, or “knot-point spline definition,” that typically accompanies a component drawing. Specifically, there are two portions of the problem: first an analytic solution must be obtained for any point on the part, e.g., given the radii and the straight lines that define the part, it is required to find an exact solution for the inner and outer profile for any arbitrary polar angle. Next, the problem of the inspection of this part must be solved, i.e., given an arbitrary sphere (representing the inspection hardware) that comes in contact with the part (inner and outer profiles) at any arbitrary polar angle, it is required to determine the exact location of that intersection. This is trivial for the case of concentric circles. In the present case, however, the spherical portion of the profiles is offset from the defined center of the part, making the analysis nontrivial. Here, a simultaneous solution of the part profiles and the sphere was obtained.
Chromophoric binaphtyl derivatives
Czech Academy of Sciences Publication Activity Database
Bříza, T.; Kejík, Z.; Vašek, P.; Králová, Jarmila; Martásek, P.; Císařová, I.; Král, V.
2005-01-01
Roč. 7, č. 17 (2005), s. 3661-3664. ISSN 1523-7060 R&D Projects: GA ČR(CZ) GA203/02/0933; GA ČR(CZ) GA309/02/1193; GA ČR GA203/02/0420; GA ČR GA301/04/1315 Institutional research plan: CEZ:AV0Z50520514 Keywords : binaphthyl derivatives * chromophore * apoptosis Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.368, year: 2005
Fundamentals and advanced techniques in derivatives hedging
Bouchard, Bruno
2016-01-01
This book covers the theory of derivatives pricing and hedging as well as techniques used in mathematical finance. The authors use a top-down approach, starting with fundamentals before moving to applications, and present theoretical developments alongside various exercises, providing many examples of practical interest. A large spectrum of concepts and mathematical tools that are usually found in separate monographs are presented here. In addition to the no-arbitrage theory in full generality, this book also explores models and practical hedging and pricing issues. Fundamentals and Advanced Techniques in Derivatives Hedging further introduces advanced methods in probability and analysis, including Malliavin calculus and the theory of viscosity solutions, as well as the recent theory of stochastic targets and its use in risk management, making it the first textbook covering this topic. Graduate students in applied mathematics with an understanding of probability theory and stochastic calculus will find this b...