Integration of Hydrogen Systems in Petroleum Refinery

Considering the importance of hydrogen in crude oil refining, it is necessary to ensure its most efficient use to satisfy refinery hydrogen requirements. Effective hydrogen management provides maximum utilization of hydrogen. The mass balance of streams containing hydrogen plays a key role in addressing the hydrogen-network optimization problem. The purpose of this work was to analyze the refinery hydrogen network, composed of hydrogen sources and sinks. Mass integration principles and techniques have been applied in the optimization of the refinery hydrogen network. The methodology of hydrogen network integration is presented in a case study of a local petroleum refinery. The main objectives are to provide different solutions for reducing the amount of hydrogen not properly used in the local refinery and which is mostly sent to the fuel system, as well as the operating costs. Hydrogen pinch analysis is applied for targeting the minimum hydrogen consumption of the hydrogen system. A superstructure-based mathematical model of the hydrogen network is developed to minimize the total operating costs. The non-linear programming optimization problem is solved by using optimization software GAMS. An additional hydrogen purification unit is introduced in the existing hydrogen network and the effect on the overall network is investigated. Network design with two hydrogen purification units has proved to be an optimal solution, with respect to the chosen objective function. These analyses and their results can assist the refinery to reduce and improve the efficiency of hydrogen management. The analyses covered only the existing equipment without additional investment

Southeast Europe Security- constant of NATO strategic concepts

Комплексна димензија безбедности у формалном и суштинском смислу детерминише комплекс људске делатности и бивствовања. У својој основи безбедност се може исказати као специфичан феномен, који је базично одређен човековом, биолошком, егзистенцијалном димензијом а потом, последичном еволуцијом и комплексом социјалне општедруштвене интеракције. Наведено нужно одређује и мултидисциплинарност у приступу и поимању феноменологије безбедности кроз призму општих, друштвених односа, посебно манифестованих друштвеним конфликтима а еволуцијским процесом и спектром системског и организацијског односа са државом као умним и смисленим продуктом обликовања друштвене заједнице. Наравно, импликације и сложене корелационе интеракције феномена безбедности производ су и објективне еволуције друштвено-економских односа, уређења, технолошког прогреса али и геополитичких односа као кондензованог сублимата и есенције „нужности“ вишедимензионалних процеса. Сложени друштвени односи, тада базирани на настанку савремених држава, носилаца суверености заједнице-група, етноса и нација, управо су били основа за јачање и формализовање специфичних обележја безбедности и геополитике у теоретском и практичном смислу. Геополитика се, управо, као наука и пракса етаблира на крају процеса формирања савремених држава, који је трајао од половине XVI па до краја XIX века, превасходно на основама феноменологије безбедности. Еволуцијом у развоју модерних држава, које су, како настајање, тако и развој имале у Европи и сама геополитичка димензија, прво заснована, а потом апсорбујући безбедност као свој базични инструментариј, детерминише општецивилизацијску динамику и савремене процесе. Исто је имало непосредне импликације на глобални, светски ниво и то у врло широком дијапазону, економском, безбедносном, политичком, културолошком, и укупно цивилизацијском. Суштински, детерминише се и усмерава опстојност „човечанства“, заснованог на савременим међународним односима, пре свега суверених држава али и доктрина које су, неспорно, засноване на основним савременим геополитичким теоријама и своју „сврху“, у коначном, апликативно имају у савременом глобалистичком концепту. III Глобализација, као концепт и доктрина поседује одређена специфична обележја, која суштински опредељују процес еволутивног развоја друштвених односа ка циљу и димензији превазилажења класичних, модерних друштава и обликовања постмодернизма, као пожељног и пројектованог облика савремених друштвених и општих односа са обележјима наднационалних и слојевитих манифестација људске праксе „постмодернистичког доба“. Овакав приступ је, примарно, исказан са позиција једног пола, базичног савременог геополитичког приступа, теорије Мора или атлантизма. На другој страни, манифестациони израз више традиционалних и конзервативнијих специфичних обележја се, суштински, исказује са другим геополитичким базичним полом, теоријом Копна или евроазијства. Но, и поред ове битне компарације, можда је још конкретнији или прецизнији исказ да су супростављена два „теоретски и филозофски различита сопства“. Наиме, примарни, видљиви али и егзактни историјски контекст даје несумњиву потврду о врло јасној цивилизацијској нужности, стварању „услова“ за егзистенцију човека, потом еволуцијом етноса, нација, држава, те нужно и неомодерним комплексом интереса појединаца и група, инструментализовано у теоријској равни последичном конфронтацијом савремених општих геополитичких приступа теорија Мора и Копна. Безбедност, као феномен, теорија и пракса људског делања представља везивно ткиво али и непосредни инструментариј апликације ових приступа. Експлицитни примери новијег доба су савремени наднационални, колективни безбедносно-политички савези, НАТО пакт и Варшавски уговор. Југоисточна Европа је имала несумњив значај и константу у еволутивном општецивилизацијском контексту али и у контексту феноменологије безбедности, као и теорије и праксе геополитике. Поред доказаног историјског контекста, ову димензију исказује и одржава као константу и детерминанту савремених геополитичких односа насталих након II светског рата а инструментализованих у конфликту две ривалске безбедносно-политичке организације, НАТО пакта и Варшавског уговора. Посматрањем настајања и еволуцијe НАТО пакта, од његовог формирања 04. априла 1949. године, анализом се долази до увиђања трансформације и адаптације путем седам стратешких концепата НАТО-а, који садрже базичне геополитичке одреднице савремене теорије атлантизма. Наведено позиционирање је, тада, у пракси представљено са Трумановом доктрином, а потом еволутивним развојем трансформисано ка, и у најновији Седми стратешки концепт НАТО-а, Активно IV ангажовање, модерна одбрана, од 19.11.2010. године. Јасни показатељи указују на потврду апликативне и инструменталне димензије геополитичке теорије Мора. Ова геополитичка теорија је исказана на имплицитан али и експлицитан начин у сваком појединачном стратешком концепту, а најчешће у општим одређењима „заштите принципа а не територија“, промовисања „западних вредности“ али и спектром безбедносних опција за „сусрет“ са новим ризицима и изазовима. Наведени општи приступ је примаран у последња три стратешка концепта (за које нису још јавно обелодањени пратећи, разрађујући документи) из 1991., 1999. и 2010. године. Безбедност и безбедносна димензија југоисточне Европе се исказује као константа и детерминанта свих стратешких концепата НАТО-а. Констатација се може аргументовати анализом димензије безбедности и односа стратешких концепата НАТО-а са два становишта, односно две референтне тачке. Први приступ у анализи јесте потвда константе и детерминишућег односа основних специфичних обележја, димензија стратешких концепата НАТО-а према безбедносној димензији југоисточне Европе. То су димензије односа организацијске структуре НАТО-а, финансијске и логистичке подршке и општи, свеобухватни однос НАТО-а према безбедносној димензији југоисточне Европе. Исказана је и потврђена несумњива интеракцијска и детерминишућа, константна и корелациона веза посматраних субјеката. Исто доводи до закључка о неспорној димензији безбедности југоисточне Европе као константе стратешких концепата НАТО-а. Са друге стране, референтна тачка анализе је постављена на апстраховање битних елемената безбедности југоисточне Европе као детерминанти и константи стратешких концепата НАТО-а. Анализом се може уочити издвајање следећих елемената: укупног безбедносног капацитета сваке појединачне државе и југоисточне Европе као безбедносног ентитета, географски положај појединачних држава и целокупног географског подручја југоисточне Европе, те индивидуални и привредни ресурси појединачних држава, као и југоисточне Европе у целини, укључујући и популацију у квантитативном и квалитативном смислу. Тако се може констатовати да се и по основу овог приступа несумњиво потврђује константна и дереминишућа димензија специфичних елемената безбедности као суштинског дела укупне безбедносне димензије југоисточне Европе у односу на стратешке концепте НАТО-а. Сублимирајући представљену елаборацију и базичне елементе истраживања, може се са високим степеном научне заснованости и инструменталне анализе НАТО V праксе, констатовати да је доказан базични хипотетички основ истраживања у смислу да: безбедност и безбедносне детерминанте представљају значајне елементе у настајању и еволуцији НАТО-а, да наведене детерминанте представљају константу у свим стратешким концептима НАТО-а и да безбедност југоисточне Европе има значајно место у редефинисању будућих глобалних концепата безбедности.The complex dimension of security in the formal and essential sense determines complex human activity and existence. In essence, the security can be expressed as a specific phenomenon, which is basically determined by a person's biological, existential dimension, and then, by a consequence of evolution and a complex of social and general interaction. Foregoing necessarily determines multidisciplinary in approach and understanding of the security phenomenology through the prism of general, social relationships, particularly manifested with social conflicts and the evolutionary process and a spectrum of systematic and organizational relation with the state as a product of intellectual and sensible community design. Of course, the implications and the complex correlation of security phenomenon interaction are product of objective evolution of socio-economic relations, development, technological progress, as well as of geopolitical relations as a condensed sublimate and essence of multidimensional process "necessity". Complex social relations based on the emergence of modern states, leaders of communitysovereignty groups, ethnic groups and nations, were the basis for strengthening and formalizing specific features of security and geopolitics in theoretical and practical terms. Geopolitics, as science and practice, becomes established at the end of modern states formation process, which lasted from the mid-sixteenth to the late nineteenth century, principally on the basis of the security phenomenology. With the evolution in modern states development, which were both created and developed in Europe, and geopolitical dimension itself, first by forming and then absorbing safety as its basic instrument, is to determine general civilizational dynamics and modern processes. That also had direct implications on a global, worldwide level, and in a very wide range- economy, security, politics, culture, and civilization in total. Essentially, it determines and directs the existence of 'humanity', based on contemporary international relations, primarily of sovereign states and doctrines which, no doubt, were based on the fundamental theories of modern geopolitics and its own "purpose", in the final, has been applied in a modern globalized concept. Globalization as a concept and doctrine has some specific characteristics, which essentially determines process of evolutionary development of social relations towards goal and dimension of overcoming the classical, modern societies and the shaping of postmodernism as a desirable form of contemporary social and general relations with characteristics of supranational and layered manifestations of „postmodern era" human practice. This approach VII is primarily expressed with one pole position, basic contemporary geopolitical approach, Sea Theory or Atlantism. On the other hand, expression of a more traditional and conservative specific characteristics is, essentially, shown with other basic geopolitical pole, by Land Theory or Eurasianism. However, despite this important comparison, maybe even more specific or precise statement would be that there are two opposing "theoretically and philosophically different selves." The primary, visible and exact historical context provides an undeniable proof of a very clear civilizational necessity of creating "conditions" for the existence of human, then with the evolution of ethnicity, nation, state, and necessarily complex of interests of individuals and groups, instrumental in theoretical level with consequential confrontation of modern general geopolitical approaches of Sea and Land Theory. Security, as a phenomenon, the theory and practice of human action is the connective tissue as well as the direct instrument of these approaches application. Explicit examples in recent times have been modern supranational collective security and political alliances, NATO and the Warsaw Pact. Southeast Europe has had an undoubted significance and constant in evaluative context of general civilizational, but also in a context of security phenomenology, as well as the theory and practice of geopolitics. In addition to proven historical context, this dimension is presented and maintained as a constant and determinant of contemporary geopolitical relations that occurred after World War II and instrumentals in a conflict of two rival security-political organizations, NATO and the Warsaw Pact. By observing NATO formation and evolution since its establishment on April 4th 1949, the analysis leads to insight in transformation and adaptation through seven strategic NATO concepts, which are containing basic guidelines of modern geopolitical theory atlantism. Specified position was then in practice represented by the Truman Doctrine, and then transformed with the evolutionary development, and in the seventh, the latest strategic NATO concept, Active engagement, modern defense, of November 19th 2010. Clear indications point to confirmation of the applicative and instrumental dimensions of geopolitical Sea Theory. This geopolitical theory is presented in an implicit and explicit way in each strategic concept, and the most commonly in definitions of "the protection of principle, not of the territory", promotion of "Western values", and with the range of security options for a "meeting" new risks and challenges. The above mentioned general approach is primary in the last three strategic concept (for which following, elaborating documents have not yet been publicly disclosed) in 1991. 1999. and 2010. Safety and security dimension of South East Europe is expressed as a constant VIII determining of the strategic NATO concept. The statement can be argued with the analysis of the security dimension and relations of NATO strategic concepts with two points of reference. The first approach in analysis is to confirm its constant and its determining relation of basic specific features, dimensions of the NATO strategic concept according to the security dimension of Southeastern Europe. These dimensions refer to the NATO organizational structures, financial and logistical support and general, comprehensive relationship between NATO and the security dimension of Southeastern Europe. It was reported and confirmed, beyond doubt, interactional and determinative, constant and correlational relation of observed subjects. That leads to the conclusion of indisputable dimension of security in Southeast Europe as a constant of NATO strategic concept. On the other hand, the reference point of the analysis is placed on abstracting the essential elements of security in Southeast Europe as determinants and constants of NATO strategic concepts. With this analysis following elements can be extracted: the total capacity of each state security and of the South East Europe as a security entity, the geographic location of individual countries and of the entire geographic South East Europe region, as well as individual and economic resources of individual countries and South East Europe as a whole, including the population in quantitative and qualitative terms. Thus it can be concluded that, based on this approach, it is undoubtedly shown that constant and determining dimension of specific security elements as an essential part of the overall security dimension of Southeastern Europe compared to the NATO strategic concept. Sublimating elaboration presented and basic research elements, it can be stated, with a high degree of scientific grounding and instrumental analyzes of NATO practice, that it has been proven a basic hypothetical basis for research in following terms: safety and security determinants are important elements in NATO creation and evolution, that stated determinants are constant in all NATO strategic concepts and that South East Europe security plays a significant role in redefining future global security concepts

The influence OF Se(IV)- and Se(VI)- modified zeolite on antioxidant and antimicrobial activity of fungi Pleurotus ostreatus and Coriolus versicolor

Poslednjih nekoliko decenija sve veća pažnja se posvećuje nutritivnim i medicinskim svojstvima gljiva. Gljive mogu transformisati biljne lignocelulozne ostatke niske hranljive vrednosti u visoko vredne delikatesne namirnice. Dokazano je i da mogu usvojiti selen, iz supstrata na kojem rastu, i da ta sposobnost zavisi od vrste gljive, kao i od oblika i koncentracije dodatog selena. Selen je esencijalni mikronutrijent, neophodan za normalno funkcionisanje organizma. Istraživanja o zastupljenosti ovog elementa ukazuju da zemljište Srbije, kao i životne namirnice spadaju među selenom najsiromašnije u svetu. Sa druge strane, Srbija raspolaže značajnim količinama zeolita i procenjuje se da se najveće zalihe ovog minerala u Evropi nalaze u blizini Vranjske Banje. Zeolitski tuf može biti modifikovan i potom upotrebljen kao adsorbent selenit- i selenat-jona. Uticaj Se(IV)- i Se(VI)-modifikovanog zeolita (SeIV-CLI i SeVI-CLI) na aktivnost enzima antioksidativnog sistema zaštite praćen je u svežim plodonosnim telima gljiva Pleurotus ostreatus i Coriolus versicolor. Jača aktivnost enzima superoksid-dismutaze i glutation-peroksidaze je utvrđena u svim uzorcima gljive P. ostreatus odgajenim na supstratu sa dodatkom selena u odnosu na kontrolu. Kod većine uzoraka gljive C. versicolor, obogaćene selenom, ustanovljena je jača aktivnost enzima superoksid-dismutaze i katalaze i slabija aktivnost glutation-peroksidaze u poređenju sa kontrolom. Primenom SDS-PAGE gel elektroforeze utvrđeno je da selen prisutan u uzorcima nije uticao na promenu molekulskih masa ispitivanih gljiva. U ovoj disertaciji izolovani su metanolni ekstrakti gljiva P. ostreatus i C. versicolor, odgajenih na supstratu bez i sa dodatkom različitih koncentracija selena u vidu Se(IV)- i Se(VI)-modifikovanog zeolita. Sadržaj selena u ekstraktima pripremljenim iz gljive P. ostreatus, obogaćene ovim elementom, je bio od 35–125 puta veći u poređenju sa kontrolnim ekstraktom, dok je kod gljive C. versicolor određen od 180–250 puta veći sadržaj selena...In recent decades, more attention is paid to the nutritional and medicinal properties of fungi. Fungi can transform lignocellulosic residues of plants with low nutritional value into high-value delicious food. It has been shown that fungi can absorb selenium from the growing substrate and that this ability depends on the type of fungus and concentration of the added selenium. Selenium is an essential micronutient, necessary for the proper functioning of the organism. Research on the distribution of this element indicates that land in Serbia, and foodstuffs are among the poorest in the world. On the other hand, Serbia has significant quantities of zeolite and it is estimated that the largest reserves of this mineral in Europe are located near Vranjska Banja. The zeolitic tuff can be modified and then used as an adsorbent for selenite- and selenate- ions. The influence of Se(IV)- and Se(VI)- modified zeolite (SeVI-CLI and SeVI-CLI) on the enzyme activity of the antioxidant protection system was monitored in fresh fruiting bodies of the fungi P. ostreatus and C. versicolor. Increased activity of the superoxide dismutase and glutathione peroxidase enzymes was measured in all samples of P. ostreatus grown on the substrate with the addition of selenium compared to the control samples. Most samples of C. versicolor enriched with selenium showed increased activity of superoxide dismutase and catalase enzymes and weaker activity of glutathione peroxidase compared to the control. By applying SDS-PAGE gel electrophoresis it was found that selenium present in the samples did not affect the molecular weight change of the tested fungi. In this dissertation methanol extracts of fungi P. ostreatus and C. versicolor grown on a substrate with and without addition of various concentrations of selenium in the form of Se(IV)- and Se(VI)-modified zeolite were isolated..

THE INFLUENCE OF THE BERRY SIZE ON THE SKIN ANTHOCYANINS CONTENT OF SOME BLACK WINE VARIETIES

The influence of the berry size on the skin anthocyanins content of the black wine grape varieties Cabernet sauvignon (clone 169), Merlot (clone 348) and Pinot noir (clone 115) was studied. Research was conducted in vineyard of Experimental estate “Radmilovac” and  in the laboratory of  Faculty of Agriculture, University of Belgrade. The aim of the research was the determination of an anthocyanin of malvidin-3-glucoside on the berry skin. For all three varieties, berries were separated into three categories: small, medium and large. Based on the results, the goal was to compare the berry skin anthocyanin content of different sizes of berries. Determination of fertility coefficients, yield indicators, analysis of the composition and structure of clusters and berries and the content of sugars and total acids were performed regularly. The obtained results on the content anthocyanin of malvidin-3-glucoside were expressed in mg/g skin fresh weight. Varieties Cabernet sauvignon and Pinot noir had an expected result, meaning that the highest anthocyanin content was recorded in the smallest berries (diameter < 7.5 mm). For the Merlot variety, the highest anthocyanin content was observed in the medium berries (diameter 7.6 – 10 mm). The lowest anthocyanin content in varieties Cabernet sauvignon and Merlot was obtained in the largest berries (diameter > 10.1 mm), which was the expected result, while in the Pinot noir variety the lowest anthocyanin content was registered in the medium category (diameter 7.6 – 10 mm). Variety Cabernet sauvignon (clone 169) showed the highest anthocyanins content (average 6.871 mg/g fresh skin weigh), followed by Merlot variety, clone 348 (average 4.61 mg/g fresh skin weigh), whereas the lowest anthocyanin content was observed in Pinot noir, clone 115 (average 4.05 mg/g fresh skin weigh)

CHEMICAL EVALUATION OF AUTOCHTHONOUS VARIETY 'PROKUPAC' RED WINE WITH THE ADDITION OF SELECTED AROMATIC HERBS

The quality parameters and chemical composition (total phenolics, total flavonoids and total anthocyanins) of the red wine obtained from the autochthonous variety 'Prokupac' (Vitis vinifera L.) with the addition of the selected aromatic herbs (Pimpinella anisum L., Cinnamomum zeylanicum, Artemisia absinthium and Glycyrrhiza glabra) were examined in two consequtive vintages (2013-2014). The differences in contents of total extract, reducing sugars and ash between the studied samples were observed, but with no statistical significance between both examined years and analyzed wines. 'Prokupac' red wines with the addition of aromatic herbs stood out with significantly higher contents of total phenolics (371.4-594.3 mg GAE L-1) and total flavonoids (136.2-243.2 mg CTE L-1) while lower total anthocyanins content was noticed, when compared to 'Prokupac' red wine used as control (p<0.05). The unfavourable weather conditions in the vintages 2013 and 2014, reflected notably on the quality of the obtained wine. To analyze the correlations between wine quality parameters and the similarity of individual wine samples, Principal Component Analysis (PCA) was used

Chemical Characterization of Fruit Wine Made from Oblacinska Sour Cherry

This paper was aimed at characterizing the wine obtained from Oblacinska, a native sour cherry cultivar. To the best of our knowledge, this is the first paper with the most comprehensive information on chemical characterization of Oblacinska sour cherry wine. The chemical composition was characterized by hyphenated chromatographic methods and traditional analytical techniques. A total of 24 compounds were quantified using the available standards and another 22 phenolic compounds were identified based on the accurate mass spectrographic search. Values of total phenolics content, total anthocyanin content, and radical scavenging activity for cherry wine sample were 1.938 mg gallic acid eqv L-1, 0.113 mg cyanidin-3-glucoside L-1, and 34.56%, respectively. In general, cherry wine polyphenolics in terms of nonanthocyanins and anthocyanins were shown to be distinctive when compared to grape wines. Naringenin and apigenin were characteristic only for cherry wine, and seven anthocyanins were distinctive for cherry wine

Uticaj vrste klona prokupca i postupka vinifikacije na sadržaj rezveratrola u vinu

The focus of this study was to investigate the effects of clones (subvarieties) of autochthonous Serbian grape variety Prokupac, along with the influence of vinification method on the content of transand cis-resveratrol as well as on total phenolic content (TPC) in wines. Wines were made from four clones of Prokupac variety (PR1, 40/1, PR6 and PR7) by application of different periods of maceration duration (1, 5 and 10 days). The effects of different species of selected wine yeasts and glucosidase enzymes on the quantity of resveratrol and TPC in wine made from PR6 variety were also investigated. The content of trans-resveratrol varied from 0.27 mg/L to 1.46 mg/L. The highest content of resveratrol was determined in Prokupac clone PR6, and the lowest in PR7 clone. An increase in resveratrol and TPC content was observed in all clones when the duration of maceration was prolonged. Wine produced by application of b enzyme preparation and 299 yeast had the highest concentration of total resveratrol (4.23 mg/L). The TPC was the highest in the wine made by combined application of yeast 299 and OE enzyme. The obtained results showed that by adequate selection of varieties, prolonged duration of maceration, application of appropriate species of yeast and enzyme preparations, it is possible to increase the content of resveratrol and other phenolic compounds in wine.Cilj ovog istraživanja bio je da se ispita uticaj različitih klonova autohtone srpske sorte Prokupac kao i postupak vinifikacije na sadržaj transi cisrezveratrola i sadržaj ukupnih polifenola (SUP) u vinima. Vina su proizvedena od četiri klona sorte Prokupac (PR1, 40/1, PR6 i PR7) primenom različitih dužina trajanja maceracije (1, 5 i 10 dana) za svaki klon. Takođe je ispitivan uticaj različitih izabranih kvasaca i enzimskih preparata glikozidaza na sadržaj rezveratrola i SUP u vinima proizvedenim od klona PR6. Sadržaj transi cisrezveratrola je određen HPLC metodom sa UV detektorom uz prethodnu tečno čvrstu ekstrakciju (SPE). Određivanje SUP je urađeno metodom po FolinČokalteu. Sadržaj transrezveratrola je bio od 0,27 mg/L do 1,46 mg/L. Najviši sadržaj rezveratrola je bio u klonu PR6 dok je najniži PR7. Povećanje sadržaja rezveratrola i SUP je primećeno kod svih klonova kada je maceracija duže trajala. Vino proizvedeno primenom enzimskog preparata glikozidaza b i kvasca 299 je imalo najviši sadržaj ukupnog rezvertrola (4,23 mg/L). Najviši SUP je bio u vinima proizvedenim primenom enzimskog preparata glikozidaza OE i kvasca 299. Dobijeni rezultati ukazuju da je izborom odgovarajućeg klona, dužine maceracije, primene odgovarajućeg kvasca i enzimskog preparata moguće povećati sadržaj rezveratrola i drugih fenolnih jedinjenja u vinu

Antibacterial potential of electrochemically exfoliated graphene sheets

Electrochemically exfoliated graphene is functionalized graphene with potential application in biomedicine. Two most relevant biological features of this material are its electrical conductivity and excellent water dispersibility. In this study we have tried to establish the correlation between graphene structure and its antibacterial properties. The exfoliation process was performed in a two electrode-highly oriented pyrolytic graphite electrochemical cell. Solution of ammonium persulfate was used as an electrolyte. Exfoliated graphene sheets were dispersed in aqueous media and characterized by atomic force microscopy, scanning electron microscopy, Raman spectroscopy, Fourier transform infrared spectroscopy, X photoelectron spectroscopy, X-ray diffraction, electron paramagnetic resonance, zeta potential, contact angle measurements and surface energy. Antibacterial assays have shown lack of the significant antibacterial activity. Major effect on bacteria was slight change of bacteria morphology. Membrane remained intact despite significant change of chemical content of membrane components.This is the peer reviewed version of the paper: Marković, Z. M., Matijašević, D. M., Pavlović, V. B., Jovanović, S. P., Holclajtner-Antunović, I. D., Špitalský, Z., Mičušik, M., Dramićanin, M. D., Milivojević, D. D., Nikšić, M. P., & Todorović Marković, B. M. (2017). Antibacterial potential of electrochemically exfoliated graphene sheets. Journal of Colloid and Interface Science, 500, 30–43. [https://doi.org/10.1016/j.jcis.2017.03.110][https://www.sciencedirect.com/science/article/abs/pii/S0021979717303776?via%3Dihub

REACTION OF TABLE GRAPE VARIETIES TO LOW WINTER TEMPERATURES

The aim ofthis study was toinvestigate theresistanceof winter buds to lowwinter temperatures oneighttablevarieties of differentripening time. The study was conducted during vine dormancy at three testing dates during winter i.e. over the last ten days of the three winter months of December, January and February. At the first, second and third dates, the air temperature in the freezing chamber was reduced to - 15oC, -20oC, and -10oC, respectively.The analysis of the average values for the study period shows that Muscat Hamburg and Smederevo Muscat had the lowest and highest average percentage of completely frozen buds (48.97% and 58.84%, respectively). The average values for partly frozen buds ranged from 29.17 % in Afuz-Ali to 33.11 % in Muscat Hamburg. The evaluation of the data on unfrozen buds suggests that the average values were within the range of 11.15 % (Smederevo Muscat) to 17.91 % (Muscat Hamburg)

School Choice and Vocational Guidance for Schoolchildren with Chronic Diseases and Other Health Problems

Osim praćenja rasta, razvoja i zdravstvenog stanja učenika tijekom školovanja, liječnik školske medicine razmišlja i o njihovu profesionalnom razvoju. Posebnu pozornost zahtijevaju učenici s kroničnim bolestima, kojih je prema istraživanjima 10 % do 15 %. Prije izbora zanimanja potrebno je upoznati roditelje i učenike s ograničenjima koja proizlaze iz prirode bolesti ili stanja. To omogućuje učenicima da razviju interes za zanimanja za koja nemaju kontraindikaciju. Sistematski pregled u osmom razredu osnovne škole procjena je učenikovih psihofi zičkih sposobnosti za nastavak srednjoškolskog obrazovanja. Tijekom pregleda provodi se profesionalno informiranje za sve učenike. Učenici s kroničnim bolestima, teškoćama u razvoju i drugim poremećajima zdravlja upućuju se na profesionalno usmjeravanje. Cilj ovog rada bio je prikaz razloga upućivanja na školsko i profesionalno usmjeravanje učenika osmih razreda, deset osnovnih škola iz Varaždinske županije, u razdoblju od školske godine 1998./99. do 2007./08. Od ukupno 4939 pregledanih učenika, na profesionalno usmjeravanje bilo je upućeno njih 458 (9,3 %). Najčešći razlozi upućivanja bili su bolesti i stanja iz skupine duševnih poremećaja i poremećaja ponašanja, sa zastupljenošću od 41,3 %. Preporuke stručnog tima za profesionalno usmjeravanje za daljnje školovanje nije slijedilo 10,5 % učenika. Za učenike s kroničnim bolestima i drugim poremećajima zdravlja bilo bi potrebno osigurati dovoljan broj upisnih mjesta u srednjim školama te kontinuirano pratiti njihov profesionalni razvoj radi intervencije u slučaju potrebe promjene škole i uvida u ishod obrazovanja. To bi se postiglo koordiniranim radom školskih liječnika, timova za profesionalno usmjeravanje, srednjih škola i županijskih upravnih odjela za prosvjetu, kulturu i šport.By following a child’s growth, development, and health, school medicine specialist can see opportunities for career choice. Special attention is needed for schoolchildren with chronic diseases and developmental difficulties, because of limited occupation choices. Studies report 10 % to 15 % prevalence of chronic diseases among schoolchildren. Parents and children should be informed about child’s limitations before career choice. It would be helpful for the students to develop interests for occupations that are not contraindicated for their condition. Physical examination gives an insight into the psycho-physical abilities of an eighth-grade primary school student for further education. During examination, counselling and vocational guidance is provided for all students with chronic diseases and other health problems. All procedures are oriented to personal abilities and preferences. The aim of this study was to analyse the reasons for vocational guidance in the Varaždin County of Croatia. It included eighth-grade students from ten primary schools from 1998/99 to 2007/08. Of 4939 students, 458 (9.3 %) with chronic diseases and health difficulties were referred to vocational guidance. Of these, 41.3 % were referred due to mental and behavioural disorders. These students were assessed and received a recommendation for at least two occupations. Forty-eight students (10.5 %) did not follow the recommendation. In a coordinated effort, school physicians, vocational guidance experts, and school and local authorities should secure enrollment of students with chronic diseases and health difficulties in secondary schools and follow their development and education to provide them the best available career opportunities