bluuebunny/crossref_metadata_2025 huggingface dataset:
Inactivation of Nitrosomonas europaea and pathogenic Escherichia coli by chlorine and monochloramine
Authors: Chauret Christian , Smith Curtis , Baribeau Hélène
Published: March 2008

The purpose of this study was to measure the chlorine and monochloramine inactivation kinetics of Nitrosomonas europaea at 21°C in the presence and absence of particles. The inactivation kinetics rates were compared with those obtained with Escherichia coli O157:H7. The results show that, in pure water, the use of free chlorine produced 4 log10 of N. europaea inactivation at a CT value of 0.8 mg.min l−1, whereas monochloramine yielded 4 log10 of inactivation at CT values of approximately 9.9–16.4 mg.min l−1. With E. coli, chlorine produced approximately 4 log10 of inactivation at a CT of 0.13 mg.min l−1, whereas monochloramine resulted in 4 log10 of inactivation at a CT of approximately 9.2 mg.min l−1. These results suggest that N. europaea is more resistant to monochloramine and chlorine than E. coli. Corrosion debris, soil material and wastewater had no statistically significant (p < 0.05) impact on the inactivation of N. europaea by either chlorine or monochloramine. It seems likely that the CT values present in distribution systems would be sufficient to control suspended cells of these two organisms, especially under conditions of breakpoint chlorination, which could be used to control nitrification. Adequate disinfection should prevent the growth of these organisms in a distribution system.
Microbiological evaluation of fecal bacterial composition from surface water through aquifer sand material
Authors: Mark Ibekwe A. , Lyon Stephen R.
Published: March 2008

When bacterial pathogens from livestock contaminate drinking water supplies, they can cause different forms of gastroenteritis. The objective of this study was to enumerate the concentrations of fecal indicator (Escherichia coli and enterococci) in surface water in order to determine removal efficiency by sand filtration. The concentrations of different indicator bacterial species were determined after running tertiary treated water through two tanks containing aquifer material. Enterococcus faecalis primers targeting the ddl gene and primers for Enterococcusfaecium were used to identify the two species in the samples. A PCR assay based on the partial sequence of the β-D-glucoronidase gene (uidA) for specific detection and differentiation of E. coli populations was used to confirm the presence of E. coli after a biochemical test. The biochemical test overestimated the percentage of E. faecium in our samples, but the PCR assay with the ddl gene produced 100% specificity with Enterococcus faecalis. The biochemical test was 91.5% specific in identifying E. coli. The composition of indicator bacteria in Santa Ana River was dominated by intestinal microflora of humans and animals; filtration by aquifer sand material may reduce the transport of indicator bacteria from surface water to groundwater.
Improved methods for modelling drinking water treatment in quantitative microbial risk assessment; a case study of Campylobacter reduction by filtration and ozonation
Authors: Smeets P. W. M. H. , Dullemont Y. J. , Van Gelder P. H. A. J. M. , Van Dijk J. C. , Medema G. J.
Published: March 2008

Quantitative microbial risk assessment (QMRA) is increasingly applied to estimate drinking water safety. In QMRA the risk of infection is calculated from pathogen concentrations in drinking water, water consumption and dose response relations. Pathogen concentrations in drinking water are generally low and monitoring provides little information for QMRA. Therefore pathogen concentrations are monitored in the raw water and reduction of pathogens by treatment is modelled stochastically with Monte Carlo simulations. The method was tested in a case study with Campylobacter monitoring data of rapid sand filtration and ozonation processes. This study showed that the currently applied method did not predict the monitoring data used for validation. Consequently the risk of infection was over estimated by one order of magnitude. An improved method for model validation was developed. It combines non-parametric bootstrapping with statistical extrapolation to rare events. Evaluation of the treatment model was improved by presenting monitoring data and modelling results in CCDF graphs, which focus on the occurrence of rare events. Apart from calculating the yearly average risk of infection, the model results were presented in FN curves. This allowed for evaluation of both the distribution of risk and the uncertainty associated with the assessment.
The economic impact of water taxes: a computable general equilibrium analysis with an international data set
Authors: Berrittella Maria , Rehdanz Katrin , Roson Roberto , Tol Richard S. J.
Published: March 2008

Water is scarce in many countries. One instrument for improving the allocation of a scarce resource is (efficient) pricing or taxation. However, water is implicitly traded on international markets, particularly through food and textiles, so that the impacts of water taxes cannot be studied in isolation, but require an analysis of international trade implications. We include water as a production factor in a multi-region, multi-sector computable general equilibrium model (GTAP), to assess a series of water tax policies. We find that water taxes reduce water use and lead to shifts in production, consumption and international trade patterns. Countries that do not levy water taxes are nonetheless affected by other countries’ taxes. Taxes on agricultural water use drive most of the economic and welfare impacts. Reductions in water use (welfare losses) are less (more) than linear with the price of water. The results are sensitive to the assumed ability to substitute other production factors for water. A water tax on production would have different effects on water use, production and trade patterns and the size and distribution of welfare losses than would a water tax on final consumption.
Water sector evolution scenarios: the case of Europe
Authors: Allouche Jeremy , Finger Matthias , Luís-Manso Patrícia
Published: March 2008

The purpose of this article is to identify possible scenarios for the evolution of the European water supply and sanitation sectors (WSS) in the next 15 years, on the basis of empirical knowledge of its dynamics. These are: tendered market, tendered market with strong regulation, administrative regulation, outsourcing, direct public management and community management. In order to do this, the authors examined the main characteristics of the sector that influence the way the sector is likely to evolve, the nature and scope of the WSS markets in Europe, as well as the role of the main actors involved in this sector (whether the European Union's institutions, public and private operators, or national regulators). This detailed analysis resulted in the framing of the main drivers of change affecting the whole sector in Europe, as well as three macro-storylines along two paradigms, a liberalized and a non-liberalized environment, that were at the basis of the identification of the water “scenarios”. The authors have finally tested the plausibility of the scenarios in selected European countries.
Immunoglobulins from amyotrophic lateral sclerosis patients enhance the frequency of glycine-mediated spontaneous inhibitory postsynaptic currents in rat hypoglossal motoneurons
Authors: Andjus P.R.
Published: March 2008

Amyotrophic lateral sclerosis (ALS) is a devastating, still incurable neurological disorder affecting upper and lower motoneurons. Passive transfer of the disease occurs when immunoglobulins from ALS patients are injected into experimental animals. It is suggested that ALS IgGs cause excitotoxicity by acting on voltage-gated Ca2+ channels. We reported previously that ALS IgGs increase spontaneous release of glutamate in hippocampal neurons. Since these cells are not normally affected in ALS, we here studied the effect of ALS IgGs on hypoglossal motoneurons in rat brain-stem slices. The frequency of spontaneous glycine-mediated inhibitory postsynaptic currents (sIPSCs) was augmented, but not that of miniature ones (mIPSCs), thus pointing to an indirect effect on release.
Changes of antioxidant enzyme activity and heat shock protein content in lymphocytes of children with asthma
Authors: Perisic Tatjana , Sreckovic M. , Matic Gordana
Published: March 2008

The aim of the present study was to examine whether changes in the antioxidant status and expression of major intracellular stress proteins are associated with pathophysiology of childhood asthma and severity of the disease. The activities of copper/zinc (CuZn) and manganese (Mn) superoxide dismutase (SOD) and catalase (CAT) in peripheral blood mononuclear cells (PBMCs) of 28 stable pediatric patients (11 mild persistent and 17 moderate persistent asthmatics) and 12 healthy children were assessed by native gel assays. The levels of two heat shock proteins (HSPs), Hsp70 and Hsp90, were examined by quantitative Western blot analysis. Moderate asthmatics, in comparison to healthy children, displayed higher activity of CuZnSOD, while differences of MnSOD and CAT activity between the groups of patients were not found. The levels of Hsp90 and the inducible isoform of Hsp70 were increased in moderate asthmatics as compared to mild asthmatics and healthy children. The results demonstrate an imbalance in cellular antioxidant and stress response systems that may contribute to pathogenesis of childhood asthma, but are not necessarily related to severity of the disease.
Determination of heavy metal deposition in the county of Obrenovac (Serbia) using mosses as bioindicators, III: Copper (Cu), Iron (Fe) and Mercury (Hg)
Authors: Sabovljevic M. , Vukojevic V. , Sabovljevic Aneta , Mihajlovic Nevena , Drazic Gordana , Vucinic Z.
Published: March 2008

In this study, the deposition of three heavy metals (Cu, Fe and Hg) in four moss taxa (Bryum argenteum, Bryum capillare, Brachythecium sp. and Hypnum cupressiforme) in the county of Obrenovac (Serbia) is presented. The distribution of average heavy metal content in all mosses in the county of Obrenovac is presented on maps, while long-term atmospheric deposition (in the mosses Bryum argenteum and B. capillare) and short-term atmospheric deposition (in the mosses Brachythecium sp. and Hypnum cupressiforme) are discussed and given in a table. Areas of the highest contaminations are highlighted.
Anatomical injuries caused by Leipotrix dipsacivagus Petanovic & Rector on cut-leaf teasel, Dipsacus laciniatus L. (Dipsacaceae)
Authors: Pecinar Ilinka , Stevanovic Branka , Rector B.G. , Petanovic Radmila
Published: March 2008

The present study highlights some conspicuous structural malformations of the native Eurasian plant Dipsacus laciniatus L. (Dipsacaceae) caused by infestation with a newly determined eriophyid mite, Leipothrix dip?sacivagus (Petanovic & Rector, 2007). The most striking structural changes, induced by mite feeding were evident in the stunted appearance of infested plants and conspicuous injuries to their leaf tissues. The significant damage it causes to D. laciniatus recommends the narrow host-range mite L. dipsacivagus as a potential agent for biological control of this plant, which is widespread everywhere in the lowlands of Europe and is listed as an invasive and noxious weed in the USA.
Nomenclatural and taxonomic notes on the flora of Serbia and the Balkan Peninsula, I: Caryophyllaceae
Authors: Niketic M. , Stevanovic V. , Tomovic Gordana
Published: March 2008

The nomenclatural analysis included 12 autochthonous and mostly endemic species from the genera Atocion Adans., Cerastium L., Heliosperma (Rchb.) Rchb., and Silene L. (Caryophyllaceae). In conformity with ICBN, 12 new infra?specific taxa are described with locus classicus on the territory of Serbia. Also presented are 24 new nomenclatural combi?nations, including several for endemic taxa not present in Serbia. The nomenclature of certain taxa is supplemented by a short taxonomic-chorological review. Results of these studies will be incorporated in the next volume of "Flora of Serbia".
The informative role of presupositions and implications confirmed by Serbian language data
Authors: Ivic Milka
Published: March 2008

Today all linguists are likely to agree that the correct interpretation of an utterance consists of the identification of what was ment by it. It has been pointed out that, besides their literal meaning, utterances may have informationally relevant presupositions or implications, which also need to be identified. The author?s analysis discloses some ways in which Serbian language data provide new support for this view.
Aleksandar Belic u slavistickom pokretu
Authors: Stankovic Bogoljub
Published: March 2008

(ruski) Na osnovanii literatury, opublikovannyh dokumentov i arhivnyh materialov v stat'e osvescaetsja vaznyj komponent dejatel'nosti Aleksandra Belica, nedostatocno predstavlennyj v otnositel'no obsirnoj literature o ego zizni i dejatel'nosti. Rec' idet o dejatel'nosti v sfere ob''edinenija slavistov, kak v nacional'nyh, tak i v mezdunarodnyh masstabah. Buduci siroko slavisticeski obrazovannym, Aleksandr Belic zanimaetsja ustanovleniem svjazej mezdu slavistami s samogo nacala svoej naucnoj dejatel'nosti. Javljaetsja odnim iz iniciatorov sozdanija Obscestva serbskogo jazyka i literatury v 1910 godu. Prinimaet ves'ma aktivnoe ucastie v rabote Pervogo mezdunarodnogo slavisticeskogo s''ezda v Prage v 1929 i Vtorogo v Varsave i Krakove v 1934 godu. Ego videnie organizovannoj slavisticeskoj dejatel'nosti osobenno jarko projavilos' v hode podgotovki k Tret'emu slavisticeskomu s''ezdu v Belgrade v 1939 godu, kotoryj iz-za razrazivsejsja Vtoroj mirovoj vojny ne sostojalsja. Iskljucitel'nye usilija Belic prilagaet v dele organizacii slavistov posle Vtoroj mirovoj vojny. V 1948 godu sozdaetsja Slavisticeskoe obscestvo NR Serbii, i Belica izbirajut ego pervym predsedatelem. Zatem po iniciative Belica ob''edinjajutsja i organizujutsja jugoslavskie slavisty, i v 1955 godu provoditsja Belgradskaja slavisti- ceskaja vstreca, na kotoroj sozdaetsja Mezdunarodnyj komitet slavistov (MKS). V nem, a takze v Jugoslavskom slavisticeskom komitete Belic intensivno zanimaetsja podgotovkoj Cetvertogo mezdunarodnogo slavisticeskogo s''ezda, provedennogo v Moskve v 1958 godu. Na s''ezde v Moskve on ves'ma intensivno rabotaet i s takim ze vdohnoveniem posle ego provedenija pristupaet k realizacii ustanovlennyh s''ezdom zadac vplot' do skoropostiznoj konciny 26 fevralja 1960 goda, kotoraja preryvaet ego dejatel'nost'.
Semanticka invarijanta kao kategorija opisa plana sadrzaja leksickih znakova
Authors: Kiklevic Aleksandar
Published: March 2008

(ruski) V stat'e rassmatrivaetsja ponjatie semanticeskogo invarianta i ego primenenie k opisaniju leksiceskih znacenij v sovremennoj rusistike. Avtor podrobno ostanavlivaetsja na naibolee izvestnyh koncepcijah semanticeskogo invarianta - N. V. Percova, L. Zibatova i G. M. Zel'dovica, pri etom kriticeski ocenivaet dannye koncepcii, glavnyj nedostatok kotoryh usmatrivaetsja v tom, cto oni ignorirujut sinergiceskij harakter jazykovoj dejatel'nosti, t.e. vzaimodejstvie jazykovoj kompetencii s kul'turno-kognitivnym kontekstom. Iz privedennogo avtorom analiza semanticeskoj derivacii vytekaet, cto opredelenie obscego znacenija (kotoroe po mysli avtora, ne mozet rassmatrivat'sja kak al'ternativa dlja mnogoznacnosti) dolzno opirat'sja na princip ambivalentnosti, t.e. na konfiguraciju deskriptivnoj semantiki znaka i zakodirovannoj v ego soderzanii kognitivnoj (kul'turno relevantnoj) informacii.
Leksema *korljЬ i kontinuanti grupe *tort na slovenskoj jezickoj teritoriji
Authors: Miloradovic Sofija
Published: March 2008

(nemacki) Mit dem vorliegenden Artikel wurde ein Versuch gemacht, alle wichtigen linguistischen Informationen, die die FP Karte 2014 *korlj? des Allgemeinen Slawischen Atlasses bietet, herauszustellen und zu kommentieren wozu zuerst eine Darlegung der Verbreitung der Kontinuanten der urslawischen Gruppe *tort auf dem slawischen Sprachraum unternommen und eine ?bersicht ?ber alle Abweichungen von der erwarteten Entwicklung gemacht wurde. Danach wurde ein Schema mit sechs unterschiedlichen Kombinationen zweier zusammensetzender Kontinuanten. Separat wurde auch eine ganze Palette an m?glichen phonetischen Realisationen der Vokalen Komponente des Reflexes der urslawischen Gruppe *tort dargeboten, wobei auch unikale Kontinuanten zum Vorschein kamen. Einzelne Abweichungen von regul?ren Entwicklungsrichtungen in den slawischen Sprachen best?tigen die Schlussfolgerung, Isolate seien unvermeidlich und die besagte Entwicklung sei in der Regel als Ergebnis einer peripheren geographischen und damit verbunden auch einer peripheren linguistischen Lage zu verstehen. Die Orte, in denen unregulare Reflexe oder unikale Formen vorkamen, befanden sich ?berwiegend in Grenzzonen oder in der Diaspora.
Kauzalna klauza u starosrpskoj poslovnopravnoj pismenosti
Authors: Pavlovic Slobodan
Published: March 2008

(nemacki) In dieser Arbeit wird eine Strukturierung des Kausalsatzes im altserbischen gesch?ftlich- rechtlichen Schrifttum er?rtert, das seit Ende des XII bis zur Mitte des XV Jahrhunderts - im Kontext des Kulturmodells der homogenen Diglossie - als einer der vollst?ndigsten funktionalen Repr?sentanten der serbischen Sprache fungierte. Obwohl diese Art des zusammengesetzten Satzes durch die verschiedenen Konjunktionen eingeleitet werden konnte (Ere, ponE/e zanE, pokoly, kako, Cko, so, zato so, zaso, da, dy, bo), kommt auf der formal syntaktischen Ebene - und zwar nur einigerma?en - die Opposition zwischen kausalen und kausal - explikativen Relationen zum Ausdruck, was man erst seit Ende des XIV Jahrhunderts bemerken kann.
Synthesis and characterization of novel porphyrin Schiff bases
Authors: Wang Lei , Feng Yaqing , Xue Jinqiang , Yukun Li
Published: March 2008

Novel porphyrin Schiff bases were synthesized by a simple Schiff base condensation in refluxing toluene between 5-(4-aminophenyl)-10,15,20-triphe?nylporphyrin (ATTP) 3 and styryl aldehydes 4-6 or p-halobenzaldehydes 7-9. The newly synthesized porphyrin Schiff bases were characterized on the basis of their chemical properties and spectral data. A good intramolecular energy transfer from the styryl unit to the porphyrin moiety was found.
Selective oxidation of isobutane on V-Mo-O mixed oxide catalysts
Authors: Mitran Gheorghita , Marcu Ioan-Cezar , Yuzhakova Tatiana , Sandulescu Ioan
Published: March 2008

Four V-Mo-O mixed metal oxides were prepared, characterized and tested for the selective oxidation of isobutane in the temperature range 350-550?C, at atmospheric pressure. Isobutane was mainly oxidized to isobutene and carbon oxides. The systems with low vanadium contents showed low activities but high isobutene selectivities, while the systems with high vanadium contents showed high activities with high carbon oxides selectivities. The effects of temperature, contact time and the molar ratio iso-butane to oxygen on the conversion of isobutane and the selectivity of the oxidation were studied.
Reactive sputtering deposition of SiO2 thin films
Authors: Radovic Ivan , Serruys Yves , Limoge Yves , Bibic Natasa
Published: March 2008

SiO2 layers were deposited in a UHV chamber by 1 keV Ar+ ion sputtering from a high purity silicon target, using different values of the oxygen partial pressure (5?10-6-2?10-4 mbar) and of the ion beam current on the target (1.67-6.85 mA). The argon partial pressure during operation of the ion gun was 1?10-3 mbar. The substrate temperature was held at 550?C and the films were deposited to a thickness of 12.5-150 nm, at a rate from 0.0018-0.035 nm s-1. Structural characterization of the deposited thin films was performed by Rutherford backscattering spectrometry (RBS analysis). Reactive sputtering was proved to be efficient for the deposition of silica at 550?C, an oxygen partial pressure of 2?10-4 mbar (ion beam current on the target of 5 mA) or, at a lower deposition rate, ion beam current of 1.67 mA and an oxygen partial pressure of 6?10-5 mbar. One aspect of these investigations was to study the consumption of oxygen from the gas cylinder, which was found to be lower for higher deposition rates.
Expeditious synthesis of 1,3,4-oxadiazole derivatives via sydnones
Authors: Kamble Ravindra , Sudha B.S. , Bhadregowda D.G.
Published: March 2008

The clean cyclization of chalcones (1a-c/2a-c) with hydrazine hydrate under microwave irradiation afforded pyrazolines derivatised with sydnone (3d-i/4d-i), which underwent 1,3-dipolar cyclo-addition with acetic anhydride to form pyrazolines appended with 1,3,4-oxadiazoles (5g-l/6g-l). The newly synthesized compounds were confirmed by spectral and elemental analyses. In comparison to classical heating, the results indicate that microwave irradiation affords higher yields, shorter reaction times (4-12 min) and cleaner reactions.
Synthesis and structural characterization of organotin(IV) complexes formed with [o,o] donor atoms of carboxylic acids
Authors: Hussain Mukhtiar , Zaman Muhammad , Hanif Muhammad , Ali Saqib , Danish Muhammad
Published: March 2008

Organotin(IV) carboxylates of the general formula RnSnL4-n (where R = Me, n-Bu or Ph, and L = ?-phenyl-2,3-(methylenedioxy)cinnamate anion or 2-(2,3-dimethlylanilino)nicotinate anion) have been prepared. The mono-, di- and tri-organotin(IV) carboxylates were synthesized by the reaction of organotin(IV) oxides or hydroxides with a stoichiometric amount of the ligand acids at an elevated temperature in dry toluene. The composition of the synthesized organotin(IV) complexes, the bonding behavior of the donor groups and structural assignments were studied by elemental analysis, FT-IR, 1H-, 13C-NMR and mass spectrometry. The spectral data suggest that the ligand acts in a bidentate manner, coordinating through the oxygen atoms. These spectroscopic techniques revealed a distorted tetrahedral geometry in the solution state for the tri-organotins, while a mean coordination number between five to six for the diorganotin(IV) dicarboxylates. In the solid phase, the tri-organotins were essentially trigonal bipyramidal polymeric while the di-organotins were octa?hedral. However, mono-organotin tricarboxylates were predicted to exist in the octahedral state both in solution as well as in the solid phase.
Q-conjugacy character and markaracter tables of tetraammineplatinum(II)
Authors: Moghani Ali
Published: March 2008

The Q-conjugacy character and Markaracter tables of finite groups were introduced by Fujita, who applied his results in this area of research to enumerate isomers of molecules. In this paper, these tables are computed for tetraammineplatinum(II).
A study of 12-tungstosilicic and 12-molybdophosphoric acids in solution
Authors: Bajuk-Bogdanovic Danica , Holclajtner-Antunovic Ivanka , Todorovic Marija , Mioc Ubavka , Zakrzewska Joanna
Published: March 2008

The behaviour of two heteropolyacids (HPAs) with quite different stability in aqueous solutions was systematically investigated by UV, IR and NMR spectroscopy and potentiometric titration. It was shown that the Keggin structure of 12-tungstosilicic acid (H4SiW12O40, WSiA) anion was sustained over a wide range of pH from 1.0 to 7.0, while the same anion type of 12-molybdophosphoric acid (H3PMo12O40, MoPA) was present only at pH 1.0. This means that under physiological conditions WSiA is dominantly present in the form of a Kegginanion, whereas the structure of MoPA is completely decomposed to molybdate and phosphate. The obtained results are of special importance for bio-medical and catalytic applications of these compounds and for a better understanding of the mechanism of their action.
Individual and simultaneous determinations of phenothiazine drugs using PCR, PLS and (OSC)-PLS multivariate calibration methods
Authors: Karimi Mohammad , Ardakani Mazloum , Behjatmanesh-Ardakani Reza , Nezhad Hormozi , Amiryan Hamzeh
Published: March 2008

Individual and simultaneous determinations of some phenothiazine drugs are described. The individual determination method is based on the reaction of chlorpromazine hydrochloride (CPH), promethazine hydrochloride (PH), trifluoperazine hydrochloride (TFPH), trimipramine maleate (TPM) and thioridazine hydrochloride (TRDH) with complex of [Fe(Bpy)3]3+. In the presence of phenothiazine derivatives, [Fe(Bpy)3]3+ is reduced easily to the colored complex [Fe(Bpy)3]2+, which shows an absorption maximum at 525 nm. The individual method is highly sensitive and suitable for 0.3-190 ?g ml-1 concentrations, with detection limits in the range 0.18-2.46 ?g ml-1. Simultaneous kinetic-spectrophotometric determination of ternary mixture of CPH, PH and TPM using principal component regression (PCR), partial least squares (PLS) and orthogonal signal correction (OSC)-PLS multivariate calibration methods is also described. The simultaneous methods are based on the difference observed in the reduction rate of the [Fe(Bpy)3]3+ complex with CPH, PH and TPM in acidic media. The results showed that the simultaneous determination of CPH, PH and TPM can be performed in the concentration ranges of 0.5-120.0, 0.3-80.0 and 5.0-100.0 ?g ml-1, respectively, for three methods (PCR, PLS and OSC-PLS). The root mean square errors of prediction (RMSEP) of CPH, PH and TPM were 0.346, 0.663 and 0.820 (for PCR) 0.317, 0.659 and 0.830 (for PLS) and 0.087, 0.124 and 0.085 (for OSC-PLS), respectively. The proposed methods were successfully applied to the individual and simultaneous determination of phenothiazine derivatives in pharmaceutical preparations, the results of which compared well with those obtained by the official method, and several synthetic (spiked) samples, whereby satisfactory results were obtained.
A study of soil moisture variability for landmine detection by the neutron technique
Authors: Avdic Senada
Published: March 2008

This paper is focused on the space and temporal variability of soil moisture experimental data acquired at a few locations near landmine fields in the Tuzla Canton, as well as on the quantification of the statistical nature of soil moisture data on a small spatial scale. Measurements of soil water content at the surface were performed by an electro-magnetic sensor over 1 25, and 100 m2 grids, at intervals of 0.2, 0.5, and 1 m, respectively. The sampling of soil moisture at different spatial resolutions and over different grid sizes has been investigated in order to achieve the quantification of the statistical nature of soil moisture distribution. The statistical characterization of spatial variability was performed through variogram and correlogram analysis of measurement results. The temporal variability of the said samples was examined over a two-season period. For both sampling periods, the spatial correlation length is about 1 to 2 m, respectively, or less. Thus, sampling should be done on a larger spatial scale, in order to capture the variability of the investigated areas. Since the characteristics of many landmine sensors depend on soil moisture, the results of this study could form a useful data base for multisensor landmine detection systems with a promising performance.
Second cohomology and nilpotency class 2
Authors: Crvenkovic Sinisa , Tasic Vladimir
Published: March 2008

Conditions are given for a class 2 nilpotent group to have no central extensions of class 3. This is related to Betti numbers and to the problem of representing a class 2 nilpotent group as the fundamental group of a smooth projective variety.
Eigenvalue bounds for the signless laplacian
Authors: Cvetkovic Dragos , Rowlinson Peter , Simic Slobodan
Published: March 2008

We extend our previous survey of properties of spectra of signless Laplacians of graphs. Some new bounds for eigenvalues are given, and the main result concerns the graphs whose largest eigenvalue is maximal among the graphs with fixed numbers of vertices and edges. The results are presented in the context of a number of computer-generated conjectures.
An attempt at frankl’s conjecture
Authors: Markovic Petar
Published: March 2008

In 1979 Frankl conjectured that in a finite union-closed family F of finite sets, F _= {?} there has to be an element that belongs to at least half of the sets in F. We prove this when |U F| _ <10.
Extendable shelling, simplicial and toric h-vector of some polytopes
Authors: Jojic Dusko
Published: March 2008

We show that the stellar subdivisions of a simplex are extendably shellable. These polytopes appear as the facets of the dual of a hypersimplex. Using this fact, we calculate the simplicial and toric h-vector of the dual of a hypersimplex. Finally, we calculate the contribution of each shelling component to the toric h-vector.
On regular anti-congruence in anti-ordered semigroups
Authors: Romano Abraham
Published: March 2008

For an anti-congruence q we say that it is regular anti-congruence on semigroup (S,=, _=, ?, ?) ordered under anti-order ? if there exists an antiorder ? on S/q such that the natural epimorphism is a reverse isotone homomorphism of semigroups. Anti-congruence q is regular if there exists a quasi-antiorder ? on S under ? such that q = ? ? ??1. Besides, for regular anti-congruence q on S, a construction of the maximal quasi-antiorder relation under ? with respect to q is shown.
Constructions of (2,n)-varieties of groupoids for n = 7, 8, 9
Authors: Goracinova-Ilieva Lidija , Markovski Smile
Published: March 2008

Given positive integer n > 2, an algebra is said to be a (2, n)- algebra if any of its subalgebras generated by two distinct elements has n elements. A variety is called a (2, n)-variety if every algebra in that variety is a (2, n)-algebra. There are known only (2, 3)-, (2, 4)- and (2, 5)-varieties of groupoids, and there is no (2, 6)-variety. We present here (2, n)-varieties of groupoids for n = 7, 8, 9.
Inference in action
Authors: van Benthem
Published: March 2008

Substructural logics arise whenever classical logic is put to new uses, and logicians from Serbia have been in the fore-front here. In this paper, we join the substructural tradition with another recent trend, viz. dynamic logic of information update. We show how these two approaches fit together in particular, through a number of representation theorems concerning structural rules. The proper background for these results turn out to be modal and dynamic logics of cross-model relations. We connect this finding with recent accounts of generalized inference, interpolation, and preservation results.
Relevant categories and partial functions
Authors: Dosen Kosta , Petric Zoran
Published: March 2008

A relevant category is a symmetric monoidal closed category with a diagonal natural transformation that satisfies some coherence conditions. Every cartesian closed category is a relevant category in this sense. The denomination relevant comes from the connection with relevant logic. It is shown that the category of sets with partial functions, which is isomorphic to the category of pointed sets, is a category that is relevant, but not cartesian closed.
Disjunction in modal description logics
Authors: Mosurovic Milenko
Published: March 2008

We investigate the complexity of satisfaction problems in modal description logics without disjunction between formulae. It is shown that simulation of disjunction in the class of all models of these logics is possible, so that the complexity remains same no matter the logics is with or without disjunction of formulae. However, the omission of disjunction, in the class of the models based on the universal relation, "turns down" the complexity of satisfaction problem i.e., if P?NP, it is not possible to simulate disjunction.
Some questions concerning minimal structures
Authors: Tanovic Predrag
Published: March 2008

An infinite first-order structure is minimal if its each definable subset is either finite or co-finite. We formulate three questions concerning order properties of minimal structures which are motivated by Pillay?s Conjecture (stating that a countable first-order structure must have infinitely many countable, pairwise non-isomorphic elementary extensions).
A few remarks on n-infinite forcing companions
Authors: Grulovic Milan
Published: March 2008

We show that the basic properties of Robinson?s infinite forcing companions are naturally transmitted to the so called n-infinite forcing companions and start with the examination of mutual relations of n-infinite forcing companions of Peano arithmetic.
Contrapunctus of the continuum problem and the measure problem
Authors: Jovanovic Aleksandar , Perovic Aleksandar
Published: March 2008

In the long history of CH (Continuum Hypothesis) and its extensions into CP (Continuum Problem) that determines cardinalities of all power sets solutions of the later are related in a variety of ways with the solution of the measure problem.
Boolean algebras in algebraic topology
Authors: Petrovic Zoran
Published: March 2008

The appearance of the complete Heyting algebra in the realm of Algebraic Topology is the main topic of the paper.
"Material" mechanics of materials
Authors: Maugin Gérard
Published: March 2008

The paper outlines recent developments and prospects in the application of the continuum mechanics expressed intrinsically on the material manifold itself. This includes applications to materially inhomogeneous materials physical effects which, in this vision, manifest themselves as quasi-in homogeneities, and the notion of thermo dynamical driving force of the dissipative progress of singular point sets on the material manifold with special emphasis on fracture, shock waves and phase-transition fronts. .
The analog equation method: A boundary-only integral equation method for nonlinear static and dynamic problems in general bodies
Authors: Katsikadelis J.T.
Published: March 2008

In this paper the Analog Equation Method (AEM) a boundary-only method is presented for solving nonlinear static and dynamic problems in continuum mechanics. General bodies are considered, that is bodies whose properties may be position or direction dependent and their response is nonlinear. The no linearity may result from both nonlinear constitutive relations (material no linearity) and large deflections (geometrical no linearity). The quintessence of the method is the replacement of the coupled nonlinear partial differential equations with variable coefficients governing the response of the body by an equivalent set of linear uncoupled equations under fictitious sources. The fictitious sources are established using a BEM-based technique and the solution of the original problem is obtained from the integral representation of the solution of the substitute problem. A variety of static and dynamic problems are solved using the AEM are presented to illustrate the method and demonstrate its efficiency and accuracy.
Effect of variable viscosity on laminar convection flow of an electrically conducting fluid in uniform magnetic field
Authors: Chakraborty S. , Borkakati A.K.
Published: March 2008

The flow of a viscous incompressible electrically conducting fluid on a continuous moving flat plate in presence of uniform transverse magnetic field, is studied. The flat plate which is continuously moving in its own plane with a constant speed is considered to be isothermally heated. Assuming the fluid viscosity as an inverse linear function of temperature, the nature of fluid velocity and temperature in presence of uniform magnetic field are shown for changing viscosity parameter at different layers of the medium. Numerical solutions are obtained by using Runge-Kutta and Shooting method. The coefficient of skin friction and the rate of heat transfer are calculated at different viscosity parameter and Prandt l number. .
Weak discontinuities in electrically conducting and radiating gases
Authors: Rai A.
Published: March 2008

The singular surface theory has been used to determine the law of propagation of weak discontinuities and the problem of growth and decay of waves. The effect of radioactive heat transfer has been treated using a differential approximation which is valid over entire optical depth range. The effects of wave geometry and magnetic field with finite electrical conductivity on the global behavior of the wave amplitude have also been studied. The two cases of diverging and converging waves have been discussed separately.
On a fractional derivative type of a viscoelastic body
Authors: Atanackovic Teodor , Novakovic Branislava
Published: March 2008

We study a viscoelastic body, in a linear stress state with fractional derivative type of dissipation. The model was formulated in [1]. Here we derive restrictions on the model that follow from Clausius-Duhem inequality. Several known constitutive equations are derived as special cases of our model. Two examples are discussed. .
Geometry and dynamics of vortex sheets in 3 dimension
Authors: Burton D.A. , Tucker R.W.
Published: March 2008

We consider the properties and dynamics of vortex sheets from a geometrical, coordinate-free, perspective. Distribution-valued forms (de Rham currents) are used to represent the fluid velocity and vorticity due to the vortex sheets. The smooth velocities on either side of the sheets are solved in terms of the sheet strengths using the language of double forms. The classical results regarding the continuity of the sheet normal component of the velocity and the conservation of vorticity are exposed in this setting. The formalism is then applied to the case of the self-induced velocity of an isolated vortex sheet. We develop a simplified expression for the sheet velocity in terms of representative curves. Its relevance to the classical Localized Induction Approximation (LIA) to vortex filament dynamics is discussed. .
Two-phase deformations within the framework of phase transition zones
Authors: Freidin A.B. , Vilchevskaya E.N. , Sharipova L.L.
Published: March 2008

We analyze conditions on the equilibrium interface and develop the concept of phase transition zones (PTZ) formed in strain-space by all deformations which can exist on the equilibrium interface. The importance of the PTZ construction follows from the fact that deformations outside the PTZ cannot exist on the interface, whatever the loading conditions. The PTZ boundary acts as a phase diagram or yield surface in strain-space. We develop a general procedure for the PTZ construction and give examples for various nonlinear elastic materials and in a case of small strains. We study orientations of the interface and jumps of strains on the interface and demonstrate that various points of the PTZ correspond to different types of strain localization due to phase transformations on different loading path. .
Recent advances in M3 (mechanics on the material manifold)
Authors: Maugin G.A.
Published: March 2008

After a brief critical review of the basic arguments involved in the various interpretations of the mechanics on the material manifold and a short remark on the relationship of that approach with the late R.Stojanovic's works, some of the recent advances in that field of continuum physics are presented. These include direct consequences in the numerics of solid-mechanics problems, general applications to the theories of plasticity, growth and mixtures, and a nonstandard application to the progress of phase- transition fronts in solids. .
Low order inelastic micromorphic polycrystals
Authors: Micunovic Milan
Published: March 2008

The paper deals with some fundamental issues essential for constitutive modelling of plastic behaviour of metals. Geometric and kinematic aspects of intragranular as well as intergranular plastic deformation of polycrystals are discussed. Homogeneous grain strains are composed into the resulting behaviour of representative volume element (RVE). A homogenization of total, plastic and elastic strains has been done. Constitutive equations by a self consistent method have been discussed. A simplest case of higher gradient theory is discussed. Elastic strain is covered by the efiective field homogenization method inside a RVE. It is underlined that plastic stretching and plastic spin are not independent. .
On bulk growth mechanics of solid-fluid mixtures
Authors: Quiligotti S.
Published: March 2008

This work aims at investigating the possibility to account for the volumetric growth of a binary solid-uid mixture, within the context of biomechanical perspectives in rational mixture theories. Growth phenomena are coarsely taken into account by describing the time evolution of the solid stress-free configuration, whose introduction contributes a part of the constitutive information to the resulting dynamics, while enriching the kinematical description of the mixture. The issue of invariance requirements under changes in observer is also addressed, and some relevant constitutive implications are briey outlined. .
MHD couette flow with heat transfer between two horizontal plates in the presence of a uniform transverse magnetic field
Authors: Bodosa G. , Borkakati A.K.
Published: March 2008

The problem of an unsteady two-dimensional flow of a viscous incompressible and electrically conducting fluid between two parallel plates in the presence of a uniform transverse magnetic field has been analyzed, when in case-I the plates are at different tem?peratures and in case-II the upper plate is considered to move with constant velocity where as the lower plate is adiabatic. Fluid velocities and temperatures are obtained and plotted graphically.
Rayleigh-Bénard convection with magnetic field
Authors: Zierep Jürgen
Published: March 2008

We discuss the solution of the small perturbation equations for a horizontal fluid layer heated from below with an applied magnetic field either in vertical or in horizontal direction. The magnetic field stabilizes, due to the Lorentz force, more or less Rayleigh-B?nard convective cellular motion. The solution of the eigenvalue problem shows that the critical Rayleigh number increases with increasing Hartmann number while the corresponding wave length decreases. Interesting analogies to solar granulation and black spots phenomena are obvious. The influence of a horizontal field is stronger than that of a vertical field. It is easy to understand this by discussing the influence of the Lorentz force on the Rayleigh-B?nard convection. This result corrects earlier calculations in the literature.
A primer on exterior differential calculus
Authors: Burton D.A.
Published: March 2008

A pedagogical application-oriented introduction to the cal?culus of exterior differential forms on differential manifolds is presented. Stokes' theorem, the Lie derivative, linear con?nections and their curvature, torsion and non-metricity are discussed. Numerous examples using differential calculus are given and some detailed comparisons are made with their tradi?tional vector counterparts. In particular, vector calculus on R3 is cast in terms of exterior calculus and the traditional Stokes' and divergence theorems replaced by the more powerful exterior expression of Stokes' theorem. Examples from classical continuum mechanics and spacetime physics are discussed and worked through using the language of exterior forms. The numerous advantages of this calculus, over more traditional ma?chinery, are stressed throughout the article. .
Drag of a growing bubble at rectilinear accelerated ascension in pure liquids and binary solutions
Authors: Askovic Radomir
Published: March 2008

The problem of predicting the drag coefficient of a growing bubble at rectilinear accelerated ascension in uniformly super?heated pure liquids and in binary solutions with a non-volatile solute at large Reynolds and Peclet numbers is discussed. In the case of pure liquids, the general solution for the drag coefficient of an accelerated growing bubble from its inception at the critical radius and through the surface-tension-, inertia-, and heat-diffusion-controlled regimes is established, as well as some necessary adaptations in the case of binary solutions with a non-volatile solute. Two particular limiting regimes in the case of pure liquids, inertia-controlled and heat-diffusion-controlled regimes, respectively, are analyzed in details, with satisfactory results. .
Almost sure stability of the thin-walled beam subjected to end moments
Authors: Pavlovic Ratko , Kozic Predrag
Published: March 2008

The dynamic stability problem of the thin-walled beams subjected to end moments is studied. Each moment consists of constant part and time-dependent stochastic non-white function. Closed form analytical solutions are obtained for simply supported boundary conditions. By using the direct Liapunov method almost sure asymptotic stability condition is obtained as function of stochastic process variance, damping coefficient, geometric and physical parameters of the beam. The stability regions for I-cross section and narrow rectangular cross section are shown in variance - damping coefficient plane when stochastic part of moment is Gaussian zero-mean process with variance ?2 and harmonic process with amplitude A.
Incompressible laminar temperature boundary layer on a body of revolution: The adiabatic case
Authors: Miric-Milosavljevic Mira , Pavlovic Milos
Published: March 2008

In the paper the universal governing equations of incompressible laminar temperature boundary layer on the sphere are obtained using the improved method of general similarity for the case of adiabatic boundary conditions. Universal solutions in one parametric approximation for Pr=1 and Pr=0.72 are obtained by numerical integration. Calculated universal functions for temperature boundary layer are presented graphically. As an example eigen-temperature of the sphere are calculated and discussed.
On the lateral vibrations of an elastic rod with varying compressive force
Authors: Stankovic Bogoljub , Atanackovic Teodor
Published: March 2008

We study lateral vibration of a simply supported axially compressed elastic rod with rotary inertia. The axial force is assumed to be a function of time. Stability of the solution is examined. The conditions are examined under which the temporal evolution of the system is a slowly varying and regularly slowly varying function. Also some properties of the generalized solution to the problem are examined. Our results on stability boundary obtained by dynamic, method agree with the results obtained by static (Euler) method.
Orthogonal series approximation for boundary layers
Authors: Adzic Nevenka , Ovcin Z.
Published: March 2008

In this paper we shall consider a class of singularly perturbed problems described by the ordinary differential equation of second order with small parameter multiplying the highest derivative and the appropriate boundary conditions, which describes certain flow problems in fluid mechanics. The solution of such problems displays boundary layers where the solution changes its values very rapidly. The domain decomposition will be performed determining layer subintervals which are adapted to the possibility of spectral approximation. The division point for the boundary layer is determined using appropriate resemblance function, so that the length of the layer subinterval varies with the degree of the truncated orthogonal series. The solution out of boundary layer is approximated by the solution of the reduced problem, and the layer solutions is approximated by truncated orthogonal series giving a smooth approximate solution upon the entire interval. The coefficients of the truncated series are evaluated using collocation technique. The order-of-magnitude of the error is estimated using the principle of inverse monotonicity and the rate of convergence for spectral approximations. .