bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inherent safety evaluation in process plants— a comparison of methodologies
Authors: Abedi Parisa , Shahriari Mohammad 
Published: August 2006

Abstract
A global population increase and an improved standard of living are generally expected. To meet these demands, an increased production of chemicals will be necessary while protecting human health and the environment. However, most current methods of chemical production are unsustainable. New designs must result in plants that assure process and operator safety, the sustained health of workers and the community, and the protection of the environment. Traditional safety precautions and process controls minimize risk but cannot guarantee the prevention of accidents followed by serious consequences. Therefore, the general approach to environmental and safety problems must be changed from reactive to proactive. One way is to further develop the concept of inherent safety.
In this paper some methods for inherent safety evaluations are reviewed. The aim of the study is to analyze the different tools available for inherent safety evaluation and identify the most important criteria in determining the inherent safety of a process plant. A model is proposed to show the interactions of different factors on the inherent safety level of a process and the model is illustrated by a case study.
The crystal structure of 1-(4-chlorophenyl)-3-(4-methylbenzoyl)thiourea
Authors: Saeed Aamer , Parvez Masood 
Published: August 2006

Abstract
1-(4-Chlorophenyl)-3-(4-methylbenzoyl)thiourea was synthesized and characterized by IR,1H and 13C NMR, mass spectroscopy and the elemental analysis. The crystal structure was confirmed from single crystal X-ray diffraction data. It crystallizes in the monoclinic space group P21/c with unit cell dimensions a=12.038(3), b=6.330(6), c=18.912(5) Å and β=100.32(3)°. There is a strong intramolecular hydrogen bond of the type N−H...O, with distance N1...O1=2.659(3) Å. The structure is composed of dimers related by inversion centers. The dimers are formed by intermolecular interactions of the type N−H...S with N...S separation of 3.440(2) Å. The mass fragmentation pattern has also been discussed.
Synthesis of novel tryptamine and β-carboline derivatives via palladium-catalyzed reaction of bromotryptamine with organic boronic acids
Authors: Fekete Melinda , Kolonits Pál , Hien Ngo , Novák Lajos 
Published: August 2006

Abstract
New tryptamine 5, 7 and β-carboline derivatives 3 were preparated by palladium-catalyzed coupling reaction of 5-bromotryptamine 1 with aryl boronic acids.
A comparison of sequential extraction procedures for fractionation of arsenic, cadmium, lead, and zinc in soil
Authors: Tlustoš Pavel , Száková Jiřina , Stárková Alena , Pavlíková Daniela 
Published: August 2006

Abstract
Twelve soil samples differing in physicochemical properties and total element contents were extracted by three sequential extraction procedures to determine As, Cd, Pb, and Zn bound to individual soil fractions and are defined by individual operational procedures. In the case of arsenic, two additional sequential extraction schemes were designed entirely for fractionation of soil containing arsenic were tested. The results confirmed that determination of element proportions bound to individual soil fractions is strongly dependent on the extracting agent and/or procedure applied within individual extracting schemes. As expected, absolute values of the elements released among the individual extracting procedures are weakly comparable. More reliable results were determined for the more mobile soil elements i.e. cadmium and zinc, in the fractions characterizing the most mobile proportions of investigated elements where significant correlations with basic soil characteristics were observed. In contrast, ambiguous results were observed for As and Pb, for both the individual extraction procedures and the effect of the soil characteristics. Regardless of the studied element, the poorest results were determined for reducible and oxidizable soil fractions. The application of at least two independent procedures or modification of the extraction scheme according to element investigated and/or particular soil characteristics can also be helpful in definition of element pattern in soils in further research.
Almost periodic solutions of neutral impulsive systems with periodic time-dependent perturbed delays
Authors: Covachev Valéry , Covacheva Zlatinka , Akça Haydar , Al-Zahrani Eada 
Published: August 2006

Abstract
A neutral impulsive system with a small delay of the argument of the derivative and another delay which differs from a constant by a periodic perturbation of a small amplitude is considered. If the corresponding system with constant delay has an isolated ω-periodic solution and the period of the delay is not rationally dependent on ω, then under a nondegeneracy assumption it is proved that in any sufficiently small neighbourhood of this orbit the perturbed system has a unique almost periodic solution.
On a family of vector space categories
Authors: Bobiński Grzegorz , Skowroński Andrzej 
Published: August 2006

Abstract
In continuation of our earlier work [2] we describe the indecomposable representations and the Auslander-Reiten quivers of a family of vector space categories playing an important role in the study of domestic finite dimensional algebras over an algebraically closed field. The main results of the paper are applied in our paper [3] where we exhibit a wide class of almost sincere domestic simply connected algebras of arbitrary large finite global dimensions and describe their Auslander-Reiten quivers.
A necessary and sufficient condition for the existence of an exponential attractor
Authors: Pražák Dalibor 
Published: August 2006

Abstract
We give a necessary and sufficient condition for the existence of an exponential attractor. The condition is formulated in the context of metric spaces. It also captures the quantitative properties of the attractor, i.e., the dimension and the rate of attraction. As an application, we show that the evolution operator for the wave equation with nonlinear damping has an exponential attractor.
IR-spectral study of photoinduced tautomerization in 1,3-diphenyl-pyrazol-5-one
Authors: Ivanova Bojidarka , Tchapkanov Atanas , Arnaudov Michail , Petkov Ivan 
Published: August 2006

AbstractThe UV-photoinduced prototropic isomerization of 1,3-diphenyl pyrazol-5-one (DPhP) embedded in polyvinyl chloride (PVC) film is studied by means of difference in IR spectral analysis. The initially existing CH-form in non-irradiated compound is transformed to NH-form, and a hydrochloride salt is stabilized because of the photodegradation of the PVC. An additional comparative IR spectral study of DPhP in different solutions as well as of its hydrochloride salts in solid state is also carried out.
Wittig and Wittig-Horner reactions under phase transfer catalysis conditions
Authors: Pascariu Aurelia , Ilia Gheorghe , Bora Alina , Bora Alina , Iliescu Smaranda , Popa Adriana , Dehelean Gheorghe , Pacureanu Liliana 
Published: August 2006

AbstractWittig and Wittig-Horner reactions are favorite tools in preparative organic chemistry. These olefination methods enjoy widespread and recognition because of their simplicity, convenience, and effciency. Phase transfer catalysis (PTC) is a very important method in synthetic organic chemistry having many advantages over conventional, homogenous reaction procedures. In this paper, we attempt to summarize the aspects concerning Wittig and Wittig-Horner reactions that take place under phase transfer catalysis conditions.
Energy and momentum losses in the process of neutrino scattering on plasma electrons in the presence of a magnetic field
Authors: Mikheev Nickolay , Narynskaya Elena 
Published: August 2006

AbstractThe neutrino-electron scattering in a dense degenerate magnetized plasma under the conditions μ 2 > 2eB ≫ μE is investigated. The volume density of the neutrino energy and momentum losses due to this process are calculated. The results we have obtained demonstrate that plasma in the presence of an external magnetic field is more transparent for neutrino than for non-magnetized plasma. It is shown that neutrino scattering under conditions considered does not lead to the neutrino force acting on plasma.
Computational determination of radiation damage effects on DNA structure
Authors: Pinak Miroslav 
Published: August 2006

AbstractMolecular dynamics (MD) studies of several radiation originated lesions on the DNA molecules are presented. The pyrimidine lesions (cytosinyl radical, thymine dimer, thymine glycol) and purine lesion (8-oxoguanine) were subjected to the MD simulations for several hundred picoseconds using MD simulation code AMBER 5.0 (4.0). The simulations were performed for fully dissolved solute molecules in water. Significant structural changes in the DNA double helical structure were observed in all cases which may be categorized as: a) the breaking of hydrogen bonds network between complementary bases and resulted opening of the double helix (cytosinyl, radical, 8-oxoguanine); b) the sharp bending of the DNA helix centered at the lesion site (thymine dimer, thymine glycol); and c) the flippingout of adenine on the strand complementary to the lesion (8-oxoguanine). These changes related to the overall collapsing of the double helical structure around the lesion, are expected to facilitate the docking of the repair enzyme into the DNA in the formation of DNA-enzyme complex. The stable DNA-enzyme complex is a necessary condition for the onset of the enzymatic repair process. In addition to structural changes, specific values of electrostatic interaction energy were determined at several lesion sites (thymine dimer, thymine glycol and 8-oxoguanine). This lesion-specific electrostatic energy is a factor that enables repair enzyme to discriminate lesion from the native site during the scanning of the DNA surface.
Multilayer optics for XUV spectral region: technology fabrication and applications
Authors: Andreev S. , Akhsakhalyan A. , Bibishkin M. , Chkhalo N. , Gaponov S. , Gusev S. , Kluenkov E. , Prokhorov K. , Salashchenko N. , Schafers F. , Zuev S. 
Published: August 2006

AbstractWe present research investigations in the field of multilayer optics in X-ray and extreme ultra-violet ranges (XUV), aimed at the development of optical elements for applications in experiments in physics and in scientific instrumentation. We discuss normal incidence multilayer optics in the spectral region of “water window”, multilayer optics for collimation and focusing of hard X-ray, multilayer dispersing elements for X-ray spectroscopy of high-temperature plasma, multilayer dispersing elements for analysis of low Z-elements. Our research pays special attention to optimization of multilayer optics for projection EUV-lithography (ψ-13nm) and short period multilayer optics.
Magnetooptical properties and FMR in granular nanocomposites (Co84Nb14Ta2)x(SiO2)100−x
Authors: Buravtsova Victoria , Guschin Vladimir , Kalinin Yuri , Kirov Sergey , Lebedeva Eugenia , Phonghirun Songsak , Sitnikov Alexander , Syr’ev Nikolay , Trofimenko Igor’ 
Published: August 2006

AbstractFor nanodimensional magnetically inhomogeneous amorphous granular films of the system (Co84Nb14Ta2)x(SiO2)100−x , 30≤x≤60 at.% the concentration dependences of the magnetooptical Kerr effect (MOKE) spectra and FMR have been investigated. The observed changes in the MOKE and FMR spectra are associated with transformations of microstructure and topology of the nanocomposites. For the compositions within the percolation region the transversal Kerr effect increases by an order of magnitude.
Clusterization of water molecules as deduced from statistical mechanical approach
Authors: Krasnoholovets Volodymyr 
Published: August 2006

AbstractUsing the methods of statistical mechanics we have shown that a homogeneous water network is unstable and spontaneously disintegrates to the nonhomogeneous state (i.e. peculiar clusters), which can be treated as an ordinary state of liquid water. The major peculiarity of the concept is that it separates the paired potential into two independent components—the attractive potential and the repulsive one, which in turn should feature a very different dependence on the distance from the particle (a water molecule in the present case). We choose the interaction potential as a combination of the ionic crystal potential and the vibratory potential associated with the elastic properties of the water system as a whole. The number ℵ of water molecules that enters a cluster is calculated as a function of several parameters, such as the dielectric constant, the mass of a water molecule, the distance between nearest molecules, and the vibrations of nearest molecules in their nodes. The number of H2O molecules that comprise a cluster is estimated as about ℵ ≈ 900, which agrees with the available experimental data.
Wave mechanics of two hard core quantum particles in A 1-D box
Authors: Jain Yatendra 
Published: August 2006

AbstractThe wave mechanics of two impenetrable hard core particles in a 1-D box is analyzed. Each particle in the box behaves like an independent entity represented by a macro-orbital (a kind of pair waveform). While the expectation value of their interaction, 〈 V HC(x) 〉, vanishes for every state of two particles, the expectation value of their relative separation, 〈 x 〉, satisfies 〈 x 〉≥λ/2 (or q ≥ π/d, with 2d=L being the size of the box). The particles in their ground state define a close-packed arrangement of their wave packets (with 〈 x 〉= λ/2, phase position separation Δϕ = 2π and momentum |q o| = π/d) and experience a mutual repulsive force (zero point repulsion) f o=h 2/2md 3 which also tries to expand the box. While the relative dynamics of two particles in their excited states represents usual collisional motion, the same in their ground state becomes collisionless. These results have great significance in determining a correct microscopic understanding of widely different many-body systems.
RuO4-mediated oxidation ofN-benzylated tertiary amines. Are amineN-oxides and iminium cations reaction intermediates?
Authors: Petride Horia , Drãghici Constantin , Florea Cristina , Petride Aurica 
Published: August 2006

Abstract
N-Benzylmorpholine,-piperidine, and-pyrrolidine (1A-C, resp.) are oxidised by RuO4 (generatedin situ) at both endocyclic and exocyclic (benzylic)N—α-methylene positions to afford lactams (and dioxo-derivatives) and benzaldehyde (and benzoyl derivatives), respectively. TheN-oxides of1A-C, formed by a minor side reaction, are not involved as intermediates. Control experiments showed the transient formation of endo- and exocyclic iminium cations trapped with NaCN as the corresponding nitriles. The proposed course of the RuO4-mediated oxidation of1A-C involves the consecutive steps1⇒iminium cations+cyclic enamine⇒oxidation products. The endocyclic/exocyclic regioselectivity of the oxidation reaction lies between 0.8 (for1A) and 2.1 (for1B). The amine cation radical and theN-α-C· carbon-centered radical seem not to be involved.
Infinite octamolybdate chains cross-linked by paramagnetic iron (II) centers
Authors: Patrut Adrian , Nicoara Adrian , Margineanu Dragos , Koop Michael , Kögerler Paul , Bögge Hartmut , Schmidtmann Marc 
Published: August 2006

Abstract
The paper presents a new polymeric polyoxomolybdate cluster with infinite octamolybdate chains cross-linked by iron (II) centers. The layer-type substance contains sodium cations sandwiched between the [Fe(H2O)4Mo8O27]∞ layers. The structure was determined by single crystal X-ray diffraction analysis. Magnetic properties, due to the presence of paramagnetic iron (II) centers, are presented and discussed.
Segregated network polymer/carbon nanotubes composites
Authors: Mierczynska A. , Friedrich J. , Maneck H. , Boiteux G. , Jeszka J. 
Published: August 2006

Abstract
In this work we present the preparation of conductive polyethylene/carbon nanotube composites based on the segregated network concept. Attention has been focused on the effect of decreasing the amount of filler necessary to achieve low resistivity. Using high- and low-grade single-walled carbon nanotube materials we obtained conductive composites with a low percolation threshold of 0.5 wt.% for high-grade nanotubes, about 1 wt% for commercial nanotubes and 1.5 wt% for low-grade material. The higher percolation threshold for low-grade material is related to low effectiveness of other carbon fractions in the network formation. The electrical conductivity was measured as a function of the single-walled carbon nanotubes content in the polymer matrix and as a function of temperature. It was also found that processing parameters significantly influenced the electrical conductivity of the composites. Raman spectroscopy was applied to study single wall nanotubes in the conductive composites.
Pulsed laser deposition of a PBN:65 morphotropic phase boundary thin film with large electrostriction
Authors: Yang Xi , Beckwith Andrew , Strikovski Mikhail 
Published: August 2006

Abstract
We deposited epitaxial thin films of Morphotropic Phase Boundary (MPB) Pb0.65Ba0.35Nb2O6 (PBN:65) on MgO substrates using pulsed laser deposition. Afterwards, a novel transmission optical experiment was developed to measure the electric field-induced bending angle of the thin film sample using a divergent incident light. From which the electric field-induced strain was obtained, and it was used to calculate the electrostrictive constant of the PBN thin film. The result is 0.000875 μm2/V2, and it is consistent with what we measured in the reflection experiment
Super-energy and Killing-Yano tensors
Authors: Tintareanu-Mircea Ovidiu , Popa Florian 
Published: August 2006

Abstract
In this paper we investigate a class of basic super-energy tensors, namely those constructed from Killing-Yano tensors, and give a generalization of super-energy tensors for cases when we start not with a single tensor, but with a pair of tensors.
Centers in domains with quadratic growth
Authors: Smoktunowicz Agata 
Published: August 2006

Abstract
Let F be a field, and let R be a finitely-generated F-algebra, which is a domain with quadratic growth. It is shown that either the center of R is a finitely-generated F-algebra or R satisfies a polynomial identity (is PI) or else R is algebraic over F. Let r ∈ R be not algebraic over F and let C be the centralizer of r. It is shown that either the quotient ring of C is a finitely-generated division algebra of Gelfand-Kirillov dimension 1 or R is PI.
High-lying doubly excited states of He and H−: electron correlations and classification schemes
Authors: Themelis Spyros 
Published: August 2006

Abstract
High-lying doubly excited states of He and H− are studied and energies and intrinsic characteristics of their wave-functions are reported. Results for energies of 3Po and 1D doubly excited states associated with the hydrogenic thresholds up to N = 20 are presented and compared to available data from the literature. The classification of these doubly excited states by approximate quantum numbers is reexamined.
Hydrostatic equilibrium and Tsallis’ equilibrium for self-gravitating systems
Authors: Du Jiulin 
Published: August 2006

Abstract
Self-gravitating systems are generally thought to behavior non-extensively due to the long-range nature of gravitational forces. We discuss a relation between the nonextensive parameter q of Tsallis statistics, the temperature gradient and the gravitational potential based on the equation of hydrostatic equilibrium for self-gravitating systems. It is suggested that the nonextensive parameter in Tsallis statistics has a clear physical meaning with regard to the non-isothermal nature of the systems with long-range interactions. Tsallis’ equilibrium distribution for the self-gravitating systems describes the property of hydrostatic equilibrium of the systems.
Conditions for the emergence of spatially asymmetric retrieval states in an attractor neural network
Authors: Koroutchev Kostadin , Korutcheva Elka 
Published: August 2006

Abstract
In this paper we show that during the retrieval process in a binary symmetric Hebb neural network, spatially localized states can be observed when the connectivity of the network is distance-dependent and a constraint on the activity of the network is imposed, which forces different levels of activity in the retrieval and learning states. This asymmetry in the activity during retrieval and learning is found to be a sufficient condition to observe spatially localized retrieval states. The result is confirmed analytically and by simulation.
Structural and optical properties of WO3 electrochromic layers prepared by the sol-gel method
Authors: Novinrooz Abdoljavad , Sharbatdaran Masoomeh , Noorkojouri Hassan 
Published: August 2006

Abstract
Thin layers of tungsten trioxide have been prepared from an aqueous solution of peroxotungstic acid (PTA) using the sol-gel method. Compositional, structural and optical characteristics of WO3 coated on indium tin oxide (ITO) conductive glass substrates were studied using X-ray diffractometery (XRD), cyclic voltammetery (CV), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Monoclinic and triclinic crystalline structures for thin film and powdered WO3 were confirmed by XRD analysis. SEM micrograph of annealed samples revealed micro cracks due to a decrease in density and a contraction of layers. EDX analysis showed that 1∶2 ratio of oxygen and tungsten atoms in the prepared films is obtained at heat treatment temperatures higher than 200 °C. Furthermore, the annealed samples showed very good electrochromic behavior in cyclic voltammetery studies. Refractive index “n” and extinction coefficient “k” values were found to be reduced by increasing the wavelength and decreasing the temperature.
An existence result for a quadrature surface free boundary problem
Authors: Barkatou Mohammed , Seck Diaraf , Ly Idrissa 
Published: August 2006

Abstract
The aim of this paper is to present two different approachs in order to obtain an existence result to the so-called quadrature surface free boundary problem. The first one requires the shape derivative calculus while the second one depends strongly on the compatibility condition of the Neumann problem. A necessary and sufficient condition of existences is given in the radial case.
Two-electron coulomb integrals with minimal group theory. Direct analytic solution and computer program
Authors: Cameron Reed B. 
Published: August 2006

Abstract
A general closed-form analytic solution is developed for two-electron Coulomb integrals such as those that appear in perturbative treatments of multielectron atoms. In developing this solution, no recourse is necessary to group theory, Clebsch-Gordan coefficients, or specialized coordinate transformations: only familiar properties of hydrogenic wavefunctions and standard integrals are employed. One constraint from group theory is adopted for the purpose of establishing an upper limit on an index of summation for computational purposes. An accurate and efficient computer program for evaluating such integrals is made available.
Two models of quantum random walk
Authors: Košík Jozef 
Published: August 2006

AbstractWe present an overview of two models of quantum random walk. In the first model, the discrete quantum random walk, we present the explicit solution for the recurring amplitude of the quantum random walk on a one-dimensional lattice. We also introduce a new method of solving the problem of random walk in the most general case and use it to derive the hitting amplitude for quantum random walk on the hypercube. The second is a special model based on a local interaction between neighboring spin-1/2 particles on a one-dimensional lattice. We present explicit results for the relevant quantities and obtain an upper bound on the speed of convergence to limiting probability distribution.