431 research outputs found

    Qualitative Analysis of Antimony, Bismuth and Arsenic in Mixtures

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    Cations of antimony, bismuth and arsenic react with potassium iodide and ether in presence of hydrochloric acid. The liquid reaction products can be hydrolysed and the three metal ions will accumulate in the third liquid phase which will form from the originally two phase system (ether-water). The next step is to determine whether the obtained product consists of an individual liquid compound only or it is a binary or ternary mixture of the liquid compounds of the three cations in question

    Reactions of Cations of the II Analytical Group with Iodide-ionand Ether in Presence of Hydrochloric Acid. Ill. Reaction of Arsenic

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    Besides antimony and bismuth, arsenic (Ill) ion also gives with iodide ion and ether in presence of hydrochloric acid a liquid reaction product, yet a greater concentration of iodide and of hydrochloric acid is needed than for the reaction of antimony and of bismuth respectively. The product is likely to be an etherate of a hydrate of the arsenious hydroiodic acid. If a drop of the product is cautiously introduced into water, hydrolysis occurs at the interface of the two liquid phases (water-reaction product), and the surface of the droplet becomes covered by a white firm film of arsenic trioxide. The reaction can serve as an identification test for arsenic, being specific and unusual in type

    Tidal variability of the motion in the Strait of Otranto

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    Various current data, collected in the Strait of Otranto during the period 1994–2007, have been analysed with the aim of describing the characteristics of the tidal motions and their contribution to the total flow variance. The principal tidal constituents in the area were the semi-diurnal (M2) and the diurnal (K1), with the latter one predominant. The total flow was, in general, more energetic along the flanks than in the middle of the strait. Specifically, it was most energetic over the western shelf and in the upper layer along the eastern flank. In spite of the generally low velocities (a few cm s<sup>−1</sup>) of the principal tidal constituents, the tidal variance has a pattern similar to that of the total flow variance, that is, it was large over the western shelf and low in the middle. The proportion of non-tidal (comprising the inertial and sub-inertial low-frequency bands) to tidal flow variances was quite variable in both time and space. The low-frequency motions dominated over the tidal and inertial ones in the eastern portion of the strait during the major part of the year, particularly in the upper and intermediate layers. In the deep, near-bottom layer the variance was evenly distributed between the low frequency, diurnal and semi-diurnal bands. An exception was observed near the western shelf break during the summer season when the contribution of the tidal signal to the total variance reached 77%. This high contribution was mainly due to the intensification of the diurnal signal at that location at both upper and bottom current records (velocities of about 10 cm s<sup>−1</sup>). Local wind and sea level data were analysed and compared with the flow to find the possible origin of this diurnal intensification. Having excluded the sea-breeze impact on the intensification of the diurnal tidal signal, the most likely cause remains the generation of the topographically trapped internal waves and the diurnal resonance in the tidal response. These waves were sometimes generated by the barotropic tidal signal in the presence of summer stratification and the strong bottom slope. This phenomenon may stimulate diapycnal mixing during the stratified season and enhance ventilation of the near-bottom layers

    RXJ 0921+4529: a binary quasar or gravitational lens?

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    We report the new spectroscopic observations of the gravitational lens RXJ 021+4529 with the multi-mode focal reducer SCORPIO of the SAO RAS 6-m telescope. The new spectral observations were compared with the previously observed spectra of components A and B of RXJ 0921+4529, i.e. the same components observed in different epochs. We found a significant difference in the spectrum between the components that cannot be explained with microlensing and/or spectral variation. We conclude that RXJ 0921+4529 is a binary quasar system, where redshifts of quasars A and B are 1.6535 +/- 0.0005 and 1.6625 +/- 0.0015, respectively.Comment: 6 pages, 5 figures, accepted for publication in The Astrophysical Journal Letter

    I distance application in the ranking of Group 8 and European Union countries by level of development

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    According to the analyses published by the international organizations, the most developed countries are those from Group 8. The group of highly developed countries is in matter, which consists of: Japan, USA, Russia, Great Britain, Italy, Germany, France and Canada. The goal of the work is to determine the ranking list of the selected countries according to the level of development in 2021 based on a certain number of macroeconomic factors. For the purposes of realizing the formulated goal, the I distance method was applied. A decision for the I distance method comes from the fact that this model satisfies all the conditions characteristic for the nature of distance, that is, for the multidimensional phenomenon of development. Based on the ranking list of Group 8 countries, the United States of America is in the first place, followed by Germany, France, the United Kingdom, Italy, Canada, the Russian Federation and Japan. Speaking about the EU countries, the Netherlands has the highest level of development according to the selected indicators, followed by Ireland, Belgium, Spain, Poland, Sweden, Austria, Denmark, Czech Republic, Luxembourg etc. The coming future will probably bring changes when it comes to the ranking on the ranking list. Changes can be expected due to the war events, demographic trends, technological achievements, and generally the replacement of the leading positions when it comes to resources. Namely, it is certain that the countries that adapt faster to other energy sources as well as to more economical use of the existing ones, will have a leading role on a global scale

    On some interconnections between combinatorial optimization and extremal graph theory

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    The uniting feature of combinatorial optimization and extremal graph theory is that in both areas one should find extrema of a function defined in most cases on a finite set. While in combinatorial optimization the point is in developing efficient algorithms and heuristics for solving specified types of problems, the extremal graph theory deals with finding bounds for various graph invariants under some constraints and with constructing extremal graphs. We analyze by examples some interconnections and interactions of the two theories and propose some conclusions

    PREVALENCA BABEZIOZE PASA NA TERITORIJI OPŠTINE TESLIĆ

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    Babezioza pasa je vektorsko oboljenje sezonskog karaktera, koje se odlikuje nalazomBabesia spp u krvi, povišenom temeperaturom, krvarenjima i splenomegalijom.Cilj rada je utvrditi prevalencu babezioze kod pasa lečenih tokom 2013. godine uveterinarskoj ambulanti "Dr Kovačević" u Tesliću. Uvidom u zdravstvene kartoneambulante, tokom 2013. godine pregledana su 183 oboljela psa. Mikroskopskimpregledom krvnog razmaza obojenog po Gimza metodi, babezioza je dokazana kod 56pasa. U martu je registrovano 3, 57% a u maju 35,71% obolelih, što odgovara pikupojavljivanja vektora, iksodidnih krpelja. Uspešna kontrola pojave babezioze kod pasanal

    Social features of the best ranked tennis players since ATP and WTA list formation

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    Основни циљ овог истраживања биo је да се утврди зависност одабира и опредељења испитаника за бављење тенисом од дефинисаних фактора социјалног статуса, као и утврђивање тачних показатеља о нивоу утицаја појединих социјалних фактора на успешност у врхунском тенису. Узорак у овом истраживању чини 56 испитаника, који су подељени у три субузорка. У првом субузорку налази се 25 тенисера, односно сви тенисери који су најмање седам дана заузимали прву позицију на АТП листи од њеног формирања 1973. године до 1. јануара 2013. године. У другом узорку налази се 21 тенисеркa, односно све тенисерке које су најмање седам дана заузимале прву позицију на ВТА листи од њеног формирања 1975. године до 1. јануара 2013. године. Трећи субузорак чини 10 најбоље рангираних српских тенисера и тенисерки на АТП и ВТА листи, а који нису ушли у претходна два субузорка (пет тенисера и пет тенисерки). Приликом анализе резултата прва два субузорка ће такође бити подељена на два дела и то на тенисере и тенисерке који су били на првим позицијама АТП и ВТА листе до 1992. године и на тенисере и тенисерке који су на тим листама били од 1992. године до 1. јануара 2013. године. Овај узорак представља репрезентативни узорак јер обухвата све тенисере и тенисерке који су бар седам дана заузимали прву позицију од како је формиран систем електронског бодовања у тенису. Такође, треба нагласити чињеницу да у појединачном врхунском спорту нема великих узорака и да се ради о најквалитетнијим појединцима у тенису у поменутом временском периоду. Са аспекта величине, ово је апсолутни узорак. Научни метод који је доминантан у овом истраживању јесте: конкретно историјски метод. Поред конкретно историјског модела, као доминантног, у раду је коришћен и компаративни (упоредни) научни метод. Овом методом су, на систематичан начин, утврђене сличности и разлике међу испитиваним социјалним карактеристикама...The main objective of this study is to determine the correlation between the subject’s selection and orientation to practice of tennis and factors of social status, as well as establishing accurate indicators that can show the level of impact on the success in professional, world-class tennis. Inferences are made due to the sample of 56 subjects who were divided into three subgroups. The first subgroup consists of 25 male tennis players who have been ranked as first for at least seven days by the ATP list, since its formation in 1973 until 1st January 2013. The second subgroup includes 21 female tennis players who have been ranked as first for at least seven days by the WTA list, since its formation in 1975 until 1st January 2013. The third subsample consists of 10 top-ranked Serbian tennis players by the ATP and WTA list who are not subject in the previous two subgroups (5 male and 5 female players). In analysis, the first two subgroups are also divided into two parts – since the formation of ATP and WTA lists until 1992, and since 1992 until 1st January 2013. When speaking about sampling characteristics it is necessary to emphasize that this is a representative sample, as it includes all tennis players who have been ranked as first by ATP or WTA for at least seven days since the formation of electronic scoring in tennis. It should also be emphasized that the individual professional sport has no great samples and that this study analyzes finest tennis individuals in mentioned period. From the standpoint of size, this is an absolute sampling. Specific historical method is dominant scientific method used during this research. Comparative method is also used to underline the differences and similarities among analyzed social characteristics..

    Diagnostics and applications of dielectric barrier discharge in contact with water.

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    Ova doktorska disertacija posvećena je istraţivanju dielektričnog barijernog praţnjenja u kontaktu sa vodom i njegovim primenama. U dielektričnom barijernom praţnjenju (DBP) sa padajućim vodenim filmom ispitana je interakcija plazme i tečnosti sa karakterizacijom fizičkih i hemijskih osobina gasne i tečne faze. Osnovni doprinos ovog istraţivanja je unapreĎenje razumevanja hemijskih procesa koje neravnoteţna plazma na atmosferskom pritisku indukuje u tečnostima. Plazma u DBP reaktoru ispitivana je uz pomoć emisione spektroskopije i električnih merenja. Ispitano je formiranje hidroksil radikala (˙OH) i dugoţivećih hemijskih vrsta (H2O2, O3, NO3 i NO2 ) u vodi i dimetil sulfoksidu koji su izloţeni delovanju neravnoteţne plazme u DBP reaktoru sa vodenim filmom u zavisnosti od gasne atmosfere (vazduh, azot, kiseonik, argon i helijum). U fokusu ovog istraţivanja bilo je formiranje hidroksil radikala i mogući uticaj njegovog zahvatanja hemijskom sondom (dimetil sulfoksid) na formiranje dugoţivećih vrsta. UtvrĎeno je da reakcija rekombinacije hidroksil radikala suštinski odreĎuje formiranje vodonik-peroksida u praţnjenjima u vazduhu, azotu i argonu. Za prostorno- vremensko istraţivanje interakcije plazme sa vodom korišćen je helijumov plazmeni mlaz u kontaktu sa vodom. Snimci razvoja praţnjenja dobijeni iCCD kamerom otkrivaju da interakcija praţnjenja sa tečnom metom moţe biti produţena nekoliko puta u zavisnosti od radnih parametara. Merene su raspodele emisije nekoliko ekscitovanih hemijskih vrsta da bi se identifikovao glavni mehanizam ekscitacije. Korišćenjem metoda Štarkove polarizacione spektroskopije, izmerena je raspodela jačine električnog polja u plazmenom mlazu koji interaguje sa tečnom metom. Ova merenja podrţana su Šlirenovom vizuelizacijom plazmenog mlaza i vodene mete. Pokazano je da neznatne promene neelektričnih parametara, kao što je udaljenost mete i brzina protoka gasa, mogu u potpunosti da promene prirodu praţnjenja. Merene vrednosti električnog polja su u opsegu 8-30 kV/cm, i zavise samo od protoka gasa i rastojanja mete, i saglasne su sa rezultatima modelovanja. Šlirenovom vizuelizacijom demonstrirana je interakcija izmeĎu protoka gasa i same plazme. Poseban doprinos ove studije je dokumentovan uticaj plazmenog mlaza na mešanje tečnosti. U okviru istraţivanja primena DBP sa vodenim filom ispitano je uklanjanje isparljivih ugljovodonika u gasnoj fazi. Demonstrirana je degradacija undekana i toluena sa smanjenom emisijom nusproizvoda kao i konverzija nerastvorljivih jedinjenja u rastvorljiva. Ispitana je inaktivacija različitih vrsta mikroorganizama u tečnostima. Pri uklanjanju zagaĎujućih supstanci u tečnoj fazi ispitan je uticaj različitih homogenih katalizatora i njihove doze na proces degradacije herbicida mezotriona, farmaceutskog jedinjenja ibuprofena i nikotina u DBP sa vodenim filmom i pokazana je visoka (do 99 %) efikasnost degradacije.The subject of the presented thesis is the study of dielectric barrier discharge in contact with water and its applications. In water falling film dielectric barrier discharge (DBD) plasma- liquid interaction has been studied, with characterization of physical and chemical properties of the gas phase and the liquid phase. The main contribution of this research is improvement of understanding of chemical processes induced in liquids by nonthermal atmospheric/pressure plasmas. Plasma in DBD reactor has been studied by optical emission spectroscopy and electrical measurements. The formation of hydroxyl radical (˙OH) and long-living chemical species (H2O2, O3, NO3 and NO2 ) generated in water and in dimethyl sulfoxide in water falling film DBD in dependence on the gas atmosphere (air, nitrogen, oxygen, argon and helium) was studied. The focus of this study was the formation of hydroxyl radical and the influence of ˙OH scavenging by dimethyl sulfoxide on the formation of long-living species. It was found that formation of hydrogen peroxide in air, nitrogen and argon discharges is determined by recombination reaction of hydroxyl radicals. For spatio-temporally resolved study of plasma-liquid interaction helium plasma jet with liquid target was used. ICCD recordings of the discharge development revealed that discharge interaction with the target can be elongated several times, depending on the operating parameters. Distributions of the emissions of several excited chemical species are measured in order to identify the main excitation mechanisms. Utilizing the method of Stark polarization spectroscopy, the electric field strength distribution measurements in helium plasma jet interacting with a liquid target are also obtained. Measurements are supported by simultaneous Schlieren imaging of both the effluent of plasma jet and water target. It was shown that the slight change of the non-electrical parameters, such as target distance and the gas flow rate can completely change the nature of the discharge. Measured electric field values are in range of 8-30 kV/cm, and depend only on the gas flow and the target distance, and they are in reasonable agreement with the modeling outcomes. Schlieren imaging demonstrated strong interaction between the gas flow and the plasma itself. Special outcome of this article is documented influence of the plasma jet discharge on the mixing of the liquid. As part of the research on the applications of water falling film DBD, the removal of volatile hydrocarbons in the gas phase was investigated. Degradation of undecane and toluene with reduced emission of by-products as well as conversion of insoluble compounds to soluble was demonstrated. Inactivation of different types of microorganisms in liquids was investigated. The influence of various homogeneous catalysts and their dosage on the degradation process of the mesotrione herbicide, the pharmaceutical compound ibuprofen and nicotine in water falling film DBD was examined and high degradation efficiency (up to 99%) was demonstrated
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