bluuebunny/crossref_metadata_2025 huggingface dataset:
Bias of Tedlar Bags in the Measurement of Agricultural Odorants
Authors: Trabue Steven L. , Anhalt Jennifer C. , Zahn James A.
Published: August 2006

Odor regulations typically specify the use of dynamic dilution olfactometery (DDO) as a method to quantify odor emissions, and Tedlar bags are the preferred holding container for grab samples. This study was conducted to determine if Tedlar bags affect the integrity of sampled air from animal operations. Air samples were collected simultaneously in both Tedlar bags and Tenax thermal desorption tubes. Sample sources originated from either a hydrocarbon‐free air tank, dynamic headspace chamber (DHC), or swine‐production facility, and were analyzed by gas chromatography–mass spectrometry–olfactometry (GC–MS–O). Several background contaminants were identified from Tedlar bags, which included the odorous compoundsN,N‐dimethyl acetamide (DMAC), acetic acid, and phenol. Samples from the DHC demonstrated that recovery of malodor compounds was dependent on residence time in the Tedlar bag with longer residence time leading to lower recovery. After 24 h of storage, recovery of C3–C6volatile fatty acids (VFA) averaged 64%, 4‐methylphenol and 4‐ethylphenol averaged 10%, and indole and 3‐methylindole were below the detection limits of GC–MS–O. The odor activity value (OAV) of grab samples collected in Tedlar bags were 33 to 65% lower following 24 h of storage. These results indicate that significant odorant bias occurs when using Tedlar bags for the sampling of odors from animal production facilities.
Change in Soluble Phosphorus in Soils following Fertilization is Dependent on Initial Mehlich‐3 Phosphorus
Authors: Bond C. Ryan , Maguire R. O. , Havlin J. L.
Published: August 2006

There is a lack of information on how fertilization and initial Mehlich‐3 phosphorus (M3P) interact to affect water soluble P (WSP) in soils. Our objectives were to (i) quantify the relationship between WSP and M3P for four textural diverse benchmark soils of North Carolina (NC) and (ii) quantify the change in WSP concentrations following P additions to soils over a wide range of initial M3P. Soils known to represent a wide range in M3P were collected from an Autryville loamy sand (loamy, siliceous, subactive, thermic Arenic Paleudults), Wasda muck (fine‐loamy, mixed, semiactive, acid, thermic Histic Humaquepts), Georgeville silt loam (fine, kaolinitic, thermic Typic Kanhapludults), and Pacolet sandy clay loam (fine, kaolinitic, thermic Typic Kanhapludults) and analyzed for M3P, Fe, Al, and WSP. An incubation study was also conducted where four samples representing a range in M3P from each series were fertilized at rates of 150 and 300 kg P ha−1, and WSP was measured at 1, 7, and 21 d after fertilization. The Wasda muck exhibited a change point at 115 mg P kg−1 across a broad range of M3P concentrations (60–238 mg kg−1) while Autryville, Georgeville, and Pacolet series (with ranges in M3P of 32–328, 119–524, 0–1034 mg P kg−1, respectively) maintained linear relationships between WSP and M3P. For the fertilized soils, significant increases in WSP occurred regardless of P rate. Yet, WSP concentrations were greater in soils with greater initial M3P. Thus, these data suggest that shifting animal waste applications to fields of relatively lower M3P concentrations would have an immediate impact on reducing risk for P losses, if all other factors are equal.
Use of Beryllium‐7 to Document Soil Redistribution following Forest Harvest Operations
Authors: Schuller Paulina , Iroumé Andrés , Walling Desmond E. , Mancilla Héctor B. , Castillo Alejandra , Trumper Rosa E.
Published: August 2006

Rapid and reliable methods for documenting soil erosion associated with forest harvest operations are needed to support the development of best management practices for soil and water conservation. To address this need, the potential for using 7Be measurements to estimate patterns and amounts of soil redistribution associated with individual post‐harvest events was explored. The 7Be technique, which was originally developed for use on agricultural land, was employed to estimate soil redistribution associated with a period of heavy rainfall within a harvested forest area located in the Lake Region of Chile (39°44′7″ S, 73°10′39″ W; 22% slope; and mean annual rainfall 2300 mm yr−1). The results provided by the 7Be technique were validated against direct measurements of soil gain or loss during the same period obtained using erosion pins. The information produced by the two approaches was similar. The results of this study demonstrate the potential for using 7Be measurements to document event‐based erosion in recently harvested forest areas.
Preferential Flow Estimates to an Agricultural Tile Drain with Implications for Glyphosate Transport
Authors: Stone Wesley W. , Wilson John T.
Published: August 2006

Agricultural subsurface drains, commonly referred to as tile drains, are potentially significant pathways for the movement of fertilizers and pesticides to streams and ditches in much of the Midwest. Preferential flow in the unsaturated zone provides a route for water and solutes to bypass the soil matrix and reach tile drains faster than predicted by traditional displacement theory. This paper uses chloride concentrations to estimate preferential flow contributions to a tile drain during two storms in May 2004. Chloride, a conservative anion, was selected as the tracer because of differences in chloride concentrations between the two sources of water to the tile drain, preferential and matrix flow. A strong correlation between specific conductance and chloride concentration provided a mechanism to estimate chloride concentrations in the tile drain throughout the storm hydrographs. A simple mixing analysis was used to identify the preferential flow component of the storm hydrograph. During two storms, preferential flow contributed 11 and 51% of total storm tile drain flow; the peak contributions, 40 and 81%, coincided with the peak tile drain flow. Positive relations between glyphosate [N‐(phosphonomethyl)glycine] concentrations and preferential flow for the two storms suggest that preferential flow is an important transport pathway to the tile drain.
Sorption and Degradation of Pesticides in Nursery Recycling Ponds
Authors: Lu Jianhang , Wu Laosheng , Newman Julie , Faber Ben , Merhaut Donald J. , Gan Jianying
Published: August 2006

Knowledge of pesticide distribution and persistence in nursery recycling pond water and sediment is critical for preventing phytotoxicity of pesticides during water reuse and to assess their impacts to the environment. In this study, sorption and degradation of four commonly used pesticides (diazinon, chlorpyrifos, chlorothalonil, and pendimethalin) in sediments from two nursery recycling ponds was investigated. Results showed that diazinon and chlorothalonil were moderately sorbed [KOC (soil organic carbon distribution coefficient) from 732 to 2.45 × 103 mL g−1] to the sediments, and their sorption was mainly attributable to organic matter content, whereas chlorpyrifos and pendimethalin were strongly sorbed (KOC ≥ 7.43 × 103 mL g−1) to the sediments, and their sorption was related to both organic matter content and sediment texture. The persistence of diazinon and chlorpyrifos was moderate under aerobic conditions (half‐lives = 8 to 32 d), and increased under anaerobic conditions (half‐lives = 12 to 53 d). In contrast, chlorothalonil and pendimethalin were quickly degraded under aerobic conditions with half‐lives < 2.8 d, and their degradation was further enhanced under anaerobic conditions (half‐lives < 1.9 d). The strong sorption of chlorpyrifos and pendimethalin by the sediments suggests that the practice of recycling nursery runoff would effectively retain these compounds in the recycling pond, minimizing their offsite movement. The prolonged persistence of diazinon and chlorpyrifos, however, implies that incidental spills, such as overflows caused by storm events, may contribute significant loads of such pesticides into downstream surface water bodies.
A kinetic method for para-nitrophenol determination based on its inhibitory effect on the catalatic reaction of catalase
Authors: Mureşanu Claudia , Copolovici Lucian , Pogącean Florina
Published: August 2006

The inhibitory effect of para-nitrophenol on the catalytic reaction of catalase was investigated. Michaelis-Menten kinetic parameters were determined from Lineweaver-Burk plots obtained in the absence or in the presence of the inhibitor. The inhibitor pattern, revealed by the Lineweaver-Burk plots, suggested a fully mixed inhibition mechanism. Spectrophotometric monitoring of the indicator reaction:
$$H_2 O_2 \xrightarrow{{catalase,para - nitrophenol}}H_2 O + \tfrac{1}{2}O_2 $$
in conjunction with initial rate measurements was employed for the kinetic determination of the inhibitor. Calibration plots of initial rate vs. para-nitrophenol concentration were linear in the concentration range 0.9·10−5–2.5·10−5 mol/L and the detection limit was 3·10−6 mol/L (417 μg/L) para-nitrophenol. Interferences from other phenolic compounds like orto-cresole, meta-and orto-nitrophenol were observed.
Oxygen detection using yttria-stabilized zirconia thin films doped with platinum
Authors: Dimitrov Dimitre , Dushkin Ceco
Published: August 2006

Yttria stabilized zirconia (YSZ) thin films are obtained using both spray-pyrolysis and dip-coating. The ability of YSZ films incorporated with platinum nanospecies (Pt-YSZ) to detect oxygen is compared with that of pure YSZ thin films using a new experimental setup. With this system, the surface electrical resistance of the films as a function the oxygen content is measured at a fixed temperature. In addition, the effects of thermal annealing on the oxygen sensitivity of the films are observed. Platinum doped samples, Pt-YSZ, show different kinetics of carrier diffusion as compared to pure YSZ samples.
New computer program to calculate the symmetry of molecules
Authors: Ashrafi Ali , Ahmadi Mohammad
Published: August 2006

In this paper we, present some MATLAB and GAP programs and use them to find the automorphism group of the Euclidean graph of the C80 fullerence with connectivity and geometry of Ih symmetry point group. It is proved that this group has order 120 and is isomorphic to Ih≊Z2×A5, where Z2 is, a cyclic group of order 2 and A5 is the alternating group on five symbols.
Molecule dynamics and combined QM/MM study on one-carbon unit transfer reaction catalyzed by GAR transformylase
Authors: Qiao Qing-An , Jin Yueqing , Cai Zhengting , Qu Rongjun , Yang Chuanlu , Wang Meishan
Published: August 2006

Both a molecule dynamic study and a combined quantum mechanics and molecule mechanics (QM/MM) study on Glycinamide ribonucleotide transformylase (GAR Tfase) catalytic mechanism are presented. The results indicate a direct one-carbon unit transfer process but not a stepwise mechanism in this reaction. The residues near the active center can fix the cofactor (N10-formyltetrahydrofolate) and GAR in proper relative positions by a H-bond network. The transition state and the minimum energy pathway are located on the potential energy surface. After all the residues (including H2O molecules) are removed from the system the activation energy has increased from 145.1 kJ/mol to 243.3 kJ/mol, and the formly transfer reaction is very hard to achieve. The interactions between coenzyme, GAR and residues near the reactive center are discussed as well.
Synthesis, structural and conformational study of selected N-substituted phthalimides
Authors: Iriepa Isabel , Javier Villasante F. , Gálvez Enrique , Herrera Antonio , Sánchez Angel , Cano Felix
Published: August 2006

This paper synthesizes N-substituted phthalimides derived from nitrogen heterocycles as potential 5-HT4 ligands by using the Mitsunobu reaction. Conformational studies of some of the new compounds have been conducted using 1H and 13C-NMR spectroscopy. Proton and carbon resonances were achieved through the application of one-dimensional selective NOE, two-dimensional NMR techniques-homonuclear COSY-45, NOESY and heteronuclear 1H-13C HMQC correlated spectroscopy- and double resonance experiments. The crystal structure of compound 1 was determined by X-ray diffraction.
Inherent safety evaluation in process plants— a comparison of methodologies
Authors: Abedi Parisa , Shahriari Mohammad
Published: August 2006

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

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

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

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

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

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.
On the torsion of linear higher order connections
Authors: Kolář Ivan
Published: August 2006

For a linear r-th order connection on the tangent bundle we characterize geometrically its integrability in the sense of the theory of higher order G-structures. Our main tool is a bijection between these connections and the principal connections on the r-th order frame bundle and the comparison of the torsions under both approaches.
An essay on model theory
Authors: Newelski Ludomir
Published: August 2006

Some basic ideas of model theory are presented and a personal outlook on its perspectives is given.
A necessary and sufficient condition for the existence of an exponential attractor
Authors: Pražák Dalibor
Published: August 2006

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

The 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

Wittig 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

The 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

Molecular 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

We 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

For 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

Using 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

The 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

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

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

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

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
f-symbols in Robertson-Walker space-time
Authors: Popa Florian , Tintareanu-Mircea Ovidiu
Published: August 2006

In a Robertson-Walker space-time, a spinning particle model is investigated. It is shown that in a stationary case a class of new structures called f-symbols exists ¢ Central European Science Journals. All rights reserved.
Super-energy and Killing-Yano tensors
Authors: Tintareanu-Mircea Ovidiu , Popa Florian
Published: August 2006

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.
Limit theorems for the Estermann zeta-function. II
Authors: Laurinčikas Antanas
Published: August 2006

A limit theorem in the sense of the weak convergence of probability measures in the space of meromorphic functions for the Estermann zeta-function is obtained.
Centers in domains with quadratic growth
Authors: Smoktunowicz Agata
Published: August 2006

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

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

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

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

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

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.
On the two-point boundary-value problem for the Riccati matrix differential equation
Authors: Laptinsky V. , Makovetsky I.
Published: August 2006

Constructive sufficient conditions for univalent resolvability of a two-point boundary value problem for nonlinear Riccati equation are obtained. An illustrative example is given.
Two-electron coulomb integrals with minimal group theory. Direct analytic solution and computer program
Authors: Cameron Reed B.
Published: August 2006

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

We 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.
Sezawa and love modes in Co/Cu superlattices
Authors: Błachowicz Tomasz
Published: August 2006

In this paper detailed theoretical study and experimental results concerning acoustic surface and undersurface propagation modes in multilayered Co/Cu superlattices are provided. The theoretical approach was adopted from that of Adler and Farnel. Experimental results were obtained in Brillouin light-scattering measurements. The Sezawa and Love acoustic modes were observed as a result of boundary conditions at the interface between hexagonal and cubic structures.
A boson approach to the structure of A=22 nuclei
Authors: Kwaśniewicz Edward , Hetmaniok Edyta , Brzostowski Jakub , Catara Francesco , Sambataro Michelangelo
Published: August 2006

We discuss a procedure to transfer the description of a fermion system from a subspace of the full shell model space built in terms of collective pairs onto a space of corresponding bosons. We apply the procedure to systems of six nucleons in the 1s0d major shell. We perform exact shell model calculations and compare them with calculations in the collective pair and boson approximations. The effects of the truncation of the boson Hamiltonian and of the consequent violation of the Pauli principle are examined.
Diffusion times and stability exponents for nearly integrable analytic systems
Authors: Lochak Pierre , Marco Jean-Pierre
Published: August 2006

For a positive integer n and R>0, we set
$$B_R^n = \left\{ {x \in \mathbb{R}^n |\left\| x \right\|_\infty< R} \right\}$$
. Given R>1 and n≥4 we construct a sequence of analytic perturbations (H
j) of the completely integrable Hamiltonian
$$h\left( r \right) = \tfrac{1}{2}r_1^2 + ...\tfrac{1}{2}r_{n - 1}^2 + r_n $$
on
$$\mathbb{T}^n \times B_R^n $$
, with unstable orbits for which we can estimate the time of drift in the action space. These functions H
j are analytic on a fixed complex neighborhood V of
$$\mathbb{T}^n \times B_R^n $$
, and setting
$$\varepsilon _j : = \left\| {h - H_j } \right\|_{C^0 (V)} $$
the time of drift of these orbits is smaller than (C(1/ɛ
j)1/2(n-3)) for a fixed constant c>0. Our unstable orbits stay close to a doubly resonant surface, the result is therefore almost optimal since the stability exponent for such orbits is 1/2(n−2). An analogous result for Hamiltonian diffeomorphisms is also proved. Two main ingredients are used in order to deal with the analytic setting: a version of Sternberg's conjugacy theorem in a neighborhood of a normally hyperbolic manifold in a symplectic system, for which we give a complete (and seemingly new) proof; and Easton windowing method that allow us to approximately localize the wandering orbits and estimate their speed of drift.
Analytic Feynman integrals of transforms of variation of cylinder type functions over Wiener paths in abstract Wiener space
Authors: Kim Myung
Published: August 2006

In this paper, we evaluate various analytic Feynman integrals of first variation, conditional first variation, Fourier-Feynman transform and conditional Fourier-Feynman transform of cylinder type functions defined over Wiener paths in abstract Wiener space. We also derive the analytic Feynman integral of the conditional Fourier-Feynman transform for the product of the cylinder type functions which define the functions in a Banach algebra introduced by Yoo, with n linear factors.
Local properties of the solution set of the operator equation in Banach spaces in a neighbourhood of a bifurcation point
Authors: Janczewska Joanna
Published: August 2006

In this work we study the problem of the existence of bifurcation in the solution set of the equation F(x, λ)=0, where F: X×R
k
→Y is a C
2-smooth operator, X and Y are Banach spaces such that X⊂Y. Moreover, there is given a scalar product 〈·,·〉: Y×Y→R
1 that is continuous with respect to the norms in X and Y. We show that under some conditions there is bifurcation at a point (0, λ0)∈X×R
k and we describe the solution set of the studied equation in a small neighbourhood of this point.
On the existence of solutions for nonlinear impulsive periodic viable problems
Authors: Cardinali Tiziana , Servadei Raffaella
Published: August 2006

In this paper we prove the existence of periodic solutions for nonlinear impulsive viable problems monitored by differential inclusions of the type x′(t)∈F(t,x(t))+G(t,x(t)). Our existence theorems extend, in a broad sense, some propositions proved in [10] and improve a result due to Hristova-Bainov in [13].
Folding theory applied to BL-algebras
Authors: Jun Young , Ko Jung
Published: August 2006

The notion of n-fold grisly deductive systems is introduced. Some conditions for a deductive system to be an n-fold grisly deductive system are provided. Extension property for n-fold grisly deductive system is established.
On almost hyperHermitian structures on Riemannian manifolds and tangent bundles
Authors: Bogdanovich Serge , Ermolitski Alexander
Published: August 2006

Some results concerning almost hyperHermitian structures are considered, using the notions of the canonical connection and the second fundamental tensor field h of a structure on a Riemannian manifold which were introduced by the second author.

With the help of any metric connection
$$\tilde \nabla $$
on an almost Hermitian manifold M an almost hyperHermitian structure can be constructed in the defined way on the tangent bundle TM. A similar construction was considered in [6], [7]. This structure includes two basic anticommutative almost Hermitian structures for which the second fundamental tensor fields h
1 and h
2 are computed. It allows us to consider various classes of almost hyperHermitian structures on TM. In particular, there exists an infinite-dimensional set of almost hyperHermitian structures on TTM where M is any Riemannian manifold.
Quaternionic and para-quaternionic CR structure on (4n+3)-dimensional manifolds
Authors: Alekseevsky Dmitri , Kamishima Yoshinobu
Published: August 2006

We define notion of a quaternionic and para-quaternionic CR structure on a (4n+3)-dimensional manifold M as a triple (ω1,ω2,ω3) of 1-forms such that the corresponding 2-forms satisfy some algebraic relations. We associate with such a structure an Einstein metric on M and establish relations between quaternionic CR structures, contact pseudo-metric 3-structures and pseudo-Sasakian 3-structures. Homogeneous examples of (para)-quaternionic CR manifolds are given and a reduction construction of non homogeneous (para)-quaternionic CR manifolds is described.
Extended finite operator calculus—an example of algebraization of analysis
Authors: Kwaśniewski Andrzej , Borak Ewa
Published: August 2006

“A Calculus of Sequences” started in 1936 by Ward constitutes the general scheme for extensions of classical operator calculus of Rota—Mullin considered by many afterwards and after Ward. Because of the notation we shall call the Ward's calculus of sequences in its afterwards elaborated form—a ψ-calculus.

The ψ-calculus in parts appears to be almost automatic, natural extension of classical operator calculus of Rota—Mullin or equivalently—of umbral calculus of Roman and Rota.

At the same time this calculus is an example of the algebraization of the analysis—here restricted to the algebra of polynomials. Many of the results of ψ-calculus may be extended to Markowsky Q-umbral calculus where Q stands for a generalized difference operator, i.e. the one lowering the degree of any polynomial by one.

This is a review article based on the recent first author contributions [1]. As the survey article it is supplemented by the short indicatory glossaries of notation and terms used by Ward [2], Viskov [7, 8], Markowsky [12], Roman [28–32] on one side and the Rota-oriented notation on the other side [9–11, 1, 3, 4, 35] (see also [33]).
Solitary wave and other solutions for nonlinear heat equations
Authors: Nikitin Anatoly , Barannyk Tetyana
Published: August 2006

A number of explicit solutions for the heat equation with a polynomial non-linearity and for the Fisher equation is presented. An extended class of non-linear heat equations admitting solitary wave solutions is described. The generalization of the Fisher equation is proposed whose solutions propagate with arbitrary ad hoc fixed velocity.
Geometric classes of Goursat flags and the arithmetics of their encoding by small growth vectors
Authors: Mormul Piotr
Published: August 2006

Goursat distributions are subbundles, of codimension at least 2, in the tangent bundles to manifolds having the flag of consecutive Lie squares of ranks not depending on a point and growing—very slowly—always by 1. The length of a flag thus equals the corank of the underlying distribution.

After the works of, among others, Bryant&Hsu (1993), Jean (1996), and Montgomery&Zhitomirskii (2001), the local behaviours of Goursat flags of any fixed length r≥2 are stratified into geometric classes encoded by words of length r over the alphabet {G,S,T} (Generic, Singular, Tangent) starting with two letters G and having letter(s) T only directly after an S, or directly after another T.

It follows from [6] that the Goursat germs sitting in any fixed geometric class have, up to translations by rk D−2, one and the same small growth vector (at the reference point) that can be computed recursively in terms of the G,S,T code. In the present paper we give explicit solutions to the recursive equations of Jean and show how, thanks to a surprisingly neat underlying arithmetics, one can algorithmically read back the relevant geometric class from a given small growth vector. This gives a secondary, Gödel-like super-encoding of the geometric classes of Goursat objects (rather than just a 1-1 correspondence between those classes and small growth vectors).
Antiinflammatory, analgesic and kinase inhibition activities of some acridine derivatives
Authors: Sondhi Sham , Bhattacharjee Gurudas , Jameel Rafid , Shukla Rakesh , Raghubir Ram , Lozach Olivier , Meijer Laurent
Published: August 2006

9-Chloro-2,4-(un)substituted acridines (1) on condensation with sulpha- diazine, sulphathiazole, and sulphaacetamide gave condensation products 3a-h. 3-Aryl-4-phenyl-2-imino-4-thiazolines (4) on condensation with 9-chloro-2,4-(un)substituted acridines (1) gave condensation products 5a–5o. Both 3a–3h and 5a–5o were purified by crystallization or by chromatography. Structures assigned to 3a–3h and 5a–5o are supported by correct spectral data. Antiinflammatory and analgesic activity screening of 3a, 3e, 3f and 5a–5c, 5e, 5g, 5i, 5m, 5n were carried out using carrageenin induced paw oedema and phenyl quinone writhing assay. Some of the compounds exhibited interesting antiinflammatory or analgesic activities.