<p>U radu se analiziraju analitički postupci za određivanje<br />opterećenja u silosima, prema teorijskim postupcima i<br />tehničkoj regulativi. Metoda integralnih relacija je<br />primenjena kod formiranja postupaka analize stanja napona u<br />silosima sa pravougaonim ćelijama i silosa sa kružnim<br />ćelijama. U analizama je uvedeno granično stanje ravnoteže i<br />asimptotsko stanje napona materijala u silosu. Na primerima<br />je dato upoređenje rezultata analize stanja napona u silosima,<br />kao i kod analize statičkih uticaja kod kružnih ćelija od<br />dejstva dodatnog lokalnog opterećenja i nesimetričnog<br />opterećenja pri pražnjenju sa velikim ekscentricitetom.</p> / <p>This paper analyzes the analytical procedures for the determination of<br />loads in silos, according to theoretical procedures and technical<br />regulations. The method of integral relations was applied for the<br />establishment of procedures for analyzing the stress state in silos with<br />rectangular cells and silos with circular cells. The analysis is<br />introduced limit state of equilibrium and asymptotic stress state of the<br />material in the silo. The examples given comparison of the results of<br />the analysis of stress state in silos, as well as in the analysis of static<br />forces of circular cells from the effects of patch load and discharge<br />loads for circular silos with large outlet eccentricities.</p>

<p>Promocija je termin koji označava sve oblike složenog komuniciranja preduzeća &ndash; pružaoca usluga sa realnim i potencijalnim potro&scaron;ačima, sa dobavljačima, sa poveriocima, sa zaposlenima, sa lokalnom samoupravom i &scaron;irom dru&scaron;tvenom zajednicom. Promocija se u svom strate&scaron;kom delovanju oslanja na sledeće instrumente (alate): propagandu, ličnu prodaju, unapređenje prodaje, odnose s javno&scaron;ću (PR) i publicitet, sponzorstvo, direktni marketing i promociju &bdquo;od usta do usta&ldquo; (word-ofmouth). Propaganda spada u jedan od najstarijih i najmasovnijih promotivnih alata, &scaron;iroko zastupljen u turističkoj delatnosti jer igra veliku ulogu u približavanju turističke ponude (posebno njenih neopipljivih elemenata) potencijalnim potro&scaron;ačima. Propaganda u turizmu za sprovođenje svojih ciljeva i zadataka koristi &scaron;iroku paletu propagandnih sredstava: grafička, oglasna, projekciona, prostorno-plastična, interaktivna sredstva. Prema izvr&scaron;enom istraživanju u na&scaron;oj zemlji usmenoj promociji &bdquo;od usta do usta&ldquo; se jo&scaron; uvek najvi&scaron;e veruje i za njom najče&scaron;će poseže kada se radi o dobijanju validnih informacija o putovanju na neku destinaciju. Istraživanjem je utvrđeno da su u grupi grafičkih sredstava najznačajnija kombinovana sredstva i prospekti, zahvaljujući svojoj dostupnosti, iscrpnosti podacima i kompleksnosti. U grafičkim sredstvima propagande pažnju turističke publike najvi&scaron;e plene fotografije i to fotografije u punom koloru, čiji pravilno odabrani motivi prenose jasnu, celovitu i istinitu poruku čime se smanjuje potreba za tekstom i &scaron;tedi na obimu ovih sredstava. Geografske karte i skice su od velikog značaja u lak&scaron;em geografskom određenju nekog mesta ili lokaliteta. Veliki deo turističke populacije (&gt; 60%) poklanja pažnju i koristi karte iz propagandnih sredstava. Stoga marketari treba da obrate pažnju pri njihovom planiranju i izradi kako bi se ukupna upotrebna vrednost propagandnih sredstava povećala, a turistima prostor učinio pregledniji i jasniji za snalaženje. Osim &scaron;tampanih sredstava, mediji koji se ističu po svom značaju u informisanju i animiranju turista su neprikosnovena televizija, gde su skoro podjednako značajni svi oblici propagande (reportaže, turistički film, oglasi) i Internet koji predstavlja iznenađenje u dobijenim rezultatima, jer se pretpostavlja da je on jo&scaron; uvek u maloj upotrebi u na&scaron;oj zemlji. Zadaci i karakter turističke propagande zahtevaju odgovarajući kvalitet sredstava i oblika njenog delovanja. Kvalitet je bitan preduslov ako se ima u vidu sve jača konkurencija na turističkom trži&scaron;tu i činjenica da je propaganda značajan činilac turističkog razvoja. &Scaron;ta čini kvalitet sredstava turističke propagande? Na ovo pitanje te&scaron;ko je definisati konačan odgovor, jer su to elementi koje praksa neprekidno menja, usavr&scaron;ava, vizuelno unapređuje. Ipak, neki elementi se mogu meriti, njihove vrednosti kvantificirati i, na kraju, izvesti ocena kvaliteta koja će činiti sastavni element u planiranju budućih propagandnih kampanja i akcija.</p> / <p>Promotion is the term denoting all the ways of complex communication between a company that provides services and real and potential customers, providers, creditors, the employed, local self-government, and with wider social community. In its strategic actions, promotion relies on the following tools: advertising, personal selling, sales promotion, public relations and publicity, sponsorship, direct and database marketing, word-of-mouth marketing. Propaganda is one of the oldest and large-scale promotion tools, widespread in tourist activities because it plays a big role in presenting tourist offer (especially its impalpable elements) to potential customers. Propaganda utilizes wide range of propaganda tools while implementing its aims and tasks: graphic, advertisement tools, projection, space-plastic, and interactive tools. According to the poll conducted in our country, people still rely the most on word-of-mouth promotion, and use it most often when they try to acquire valid information about traveling to a certain destination. The poll established that combined tools and prospects are the most significant in the graphic group of tools because of their availability, abundance of information, and complexity. Among propaganda graphic tools, tourists are most attracted by photographs i.e., full-color photographs with motives that were chosen properly to convey comprehensible, detailed, and true message. Thus, there is less need for text and this economizes on the volume of those tools. Geographic maps and sketches are also of great importance in determining geographical coordinates of a place or locality. Huge percentage of tourists (around 60%) pays attention and uses maps from propaganda tools. Thus, the map-makers should pay good attention when drawing them because that would increase total serviceable value of propaganda tools, and tourists would have a good layout of the area and it would not be hard to find the way. Besides the printed tools, TV and Internet are media tools that are prominent in their importance in informing and animating tourists. With TV, almost all forms of propaganda are equally important: reports, tourist films, advertisements, while Internet was a surprise according to the results because it is still assumed that it is not so wide-spread in our country. Tasks and character of tourist propaganda require certain quality tools and ways of its functioning. Taking into account strong competition at the tourist market and the fact that propaganda is an important element in tourist development, the quality is an important precondition. What makes the quality element in tourist propaganda? It would not be easy to give a definite reply to this question, because these are the elements that are constantly amended, improved, visually upgraded by the practice. However, some elements could be measured, their values qualified, and at the end the evaluation of quality could be produced, and it would then be the integral part of planning future propaganda campaigns and actions.</p>

<p>Cilj istraživanja doktorske disertacije je bio ispitivanje mogućnosti primene<br />vlakana od nerđajućeg čelika za koalescenciju kapi mineralnih ulja različite polarnosti<br />pri različitoj permeabilnosti sloja. Pored toga cilj je bio i komparativna analiza efikasnosti separacije ispitivanih ulja vlaknima visoke i niske energije povr&scaron;ine. Postavljena je i modifikovana metoda kinetike upijanja tečnosti za ocenu sklonosti ulja ka odabranim vlaknima od kojih se formira sloj. Po prvi put je primenjena i metoda ve&scaron;tačkih neuronskih mreža za simulaciju koalescentne filtracije.<br />Eksperimentalni program koalescentne filtracije je realizovan na model emulziji<br />dispergovanog ulja u vodi konstantne ulazne koncentracije 500 mg/l,<br />pri konstantnoj temperaturi od 20&deg;C, horizontalnoj orijentaciji toka fluida i<br />prosečnoj veličini kapi ulja od 10 &mu;m. Uticaj geometrije sloja ispitivan je variranjem<br />permeabilnosti u opsegu od 0,1810^-9 m2 do 5,510^-9 m² za konstantnu<br />debljinu sloja od 5 cm. Testirana su tri uzorka mineralnog ulja velikog raspona<br />viskoznosti i polarnosti. Svi ogledi su realizovani pri konstantnoj brzini fluida u intervalu od 10 m/h do 80 m/h. Izlazna koncentracija dispergovane faze<br />odredivana je FTIR spektrofotometrijom.<br />Značajan doprinos u istraživanju fenomena koalescencije u sloju vlakana<br />ogleda se u utvrdivanju mogućnosti primene vlakana nerdajućeg čelika na<br />separaciju kapi mineralnih ulja, razumevanju simultanog uticaja energije<br />povr&scaron;ine, geometrije sloja i prirode uljne faze, kao i uvodenju nove veličine<br />izo-izlazne koncentracije. Test odredivanja kinetike upijanja tečnosti je pokazao<br />da odnos liofilno-liofobne kva&scaron;ljivosti materijala adekvatno opisuje sklonost<br />nekog filtarskog materijala ka separaciji ulja mineralnog porekla. Ovako<br />sveobuhvatna analiza uticaja različitih parametara na efikasnost koalescentne<br />filtracije, data u ovoj disertaciji, nije zabeležena u dostupnim literaturnim navodima.<br />Rezultati doktorske disertacije omogući će skraćivanje vremena i materijalnih<br />tro&scaron;kova neophodnih za projektovanje koalescera, jer smanjuju potreban<br />obim eksperimentalnih istraživanja potrebnih za uspe&scaron;no projektovanje.<br />Odabrani uslovi rada, prvenstveno prečnik vlakana materijala u odnosu na<br />ulaznu veličinu kapi, kao i način njihovog pakovanja, uz obezbedivanje poznate<br />i definisane permeabilnosti, obezbedili su željenu separaciju, čija se efikasnost<br />separacije kapi ispitivanih ulja vlaknima od nerdajućeg čelika kreće u<br />opsegu od 91% do 99% za opseg brzina fluida od 10 m/h do 50 m/h. Kod sloja<br />vlakana od nerdajućeg čelika efikasnija separacija je zapažena pri niskim vrednostima<br />permeabilnosti, dok je kod polimernog materijala obrnut slučaj. Zaključeno je da, u postojećim okolnostima, kod posmatranih materijala dominiraju<br />različiti mehanizmi koalescencije u sloju. Oblik zavisnosti izlazne koncentracije<br />od brzine i permeabilnosti za oba ispitivana materijala, nerdajući čelik i<br />polipropilen, je sličan. Polipropilen ima veći radni opseg brzina u odnosu na<br />nerdajući čelik. Medutim, nerdajući čelik uspe&scaron;nije separi&scaron;e ulje najniže viskoznosti<br />u oblasti niskih vrednosti permeabilnosti i pri niskim radnim brzinama<br />u odnosu na polipropilen. Zadovoljavajući kvalitet separacije se kod polipropilena<br />ostvaruje pri najvi&scaron;oj permeabilnosti i u &scaron;irokom opsegu brzina, dok se<br />kod nerđajućeg čelika najvi&scaron;e vrednosti kritične brzine za ceo opseg ispitivane<br />viskoznosti ostvaruju pri najnižoj permeabilnosti sloja.</p> / <p>The aim of the doctoral thesis was to investigate the possibility of the stainless<br />steel fibers application for the coalescence of mineral oil drops with different<br />polarity varying also the bed permeability. Additional aim was the comparative<br />analysis of the tested oil separation efficiency with fibers that have high<br />and low surface energy. The method for the evaluation of the fiber-liquid wetting<br />kinetic was set up and modified in order to assess the affinity of oil to the<br />selected fiber that was used to form the filtration bed. For the first time, the<br />method of artificial neural networks was applied to simulate the coalescence<br />filtration.<br />Experimental program of coalescence filtration was performed on oil-in-water<br />model emulsion with constant inlet concentration of 500 mg/l, at a constant<br />temperature of 20&deg;C, horizontal fluid flow orientation and average oil drop<br />size of 10 &mu;m. The influence of bed geometry was studied varying bed permeability<br />in the range from 0,1810^-9 m2 to 5,51010^-9 m2 for the constant layer thickness of 5 cm. Three samples of mineral oil that have large range of viscosity<br />and polarity were tested. All experiments were carried out at constant<br />fluid velocity in the range from 10 m/h to 80 m/h. The output dispersed phase<br />concentration was determined by FTIR spectrophotometry.<br />A significant contribution to the research of the coalescence phenomenon in<br />a fiber bed was achieved by determining the possibility to use stainless steel<br />fibers for the separation of mineral oil drops, broadening the apprehension<br />of the simultaneous influence of surface energy, bed geometry and oil phase<br />nature, as well as the introduction of an iso-output concentration as a new<br />parameter. The evaluation of the fiber-liquid wetting kinetic showed that the<br />lipophilic-lyophobic wettability ratio of the material adequately describes the<br />tendency of a filter material for the mineral oil separation. Such comprehensive<br />analysis of the various parameters impact on the efficiency of coalescence<br />filtration, presented in this thesis, was not found in available literature. The results<br />of the doctoral thesis will enable the reduction of time and material cost<br />needed for the design of coalescer, by decreasing the extent of experimental<br />research necessary for successful design.<br />Selected working conditions, primarily the fiber diameter in relation to the input<br />drop size, as well as bed packaging, while ensuring the known and defined<br />bed permeability, provided the desired separation, with the oil drop separation<br />efficiency of tested stainless steel fibers in the range from 91% to 99% for a fluid<br />velocity range from 10 m/h to 50 m/h. When stainless steel was used, more<br />efficient separation was observed for the low bed permeability, whereas for<br />the polymer fibers the reverse order was identified. It was concluded that, in<br />the existing circumstances, different mechanisms of oil drop coalescence dominate<br />for these materials. The dependence of output concentration from the<br />velocity and bed permeability for both tested materials, stainless steel and polypropylene, was similar. Polypropylene has a higher operating velocity range<br />in comparison to stainless steel. However, when compared to polypropylene,<br />stainless steel separates more successfully the oil with the lowest viscosity in<br />the low bed permeability and at low fluid velocity domain. Satisfactory quality<br />of separation with polypropylene is achieved at the highest bed permeability<br />and in a wide fluid velocity range, whereas, with the stainless steel, the highest<br />values of critical velocity, for the entire range of tested viscosity, are realized at<br />the lowest bed permeability.</p>

<p>Ova doktorska disertacija ima za cilj sticanje naučnog saznanja o nivou i<br />značaju uticaja verbalno-vizuelnog materijala sa sredstava vizuelnih komunikacija na<br />usvajanje vokabulara engleskog kao stranog jezika. Dosada&scaron;nja istraživanja vezana za<br />ovu temu se uglavnom usredsređuju na mlađi uzrast učenika, dok se ova disertacija<br />bavi proučavanjem pomenute pojave na univerzitetskom nivou ˗ kod studenata<br />engleskog jezika i književnosti.<br />Ovo istraživanje je bazirano na četiri izvora podataka: (1) upitniku koji su<br />popunili studenti prve, druge, treće i četvrte godine (N=71) s ciljem da omogući op&scaron;te<br />podatke o studentima i da se stekne uvid u njihova mi&scaron;ljenja i stavove o upotrebi<br />verbalno-vizuelnog materijala u nastavi vokabulara, kao i o značaju sredstava<br />vizuelnih komunikacija na usvajanje vokabulara engleskog kao stranog jezika; (2)<br />testu kao sastavnom delu eksperimenta sa paralelnim grupama, koji je sproveden na<br />uzorku studenata druge i četvrte godine (N=41) gde je verbalno-vizuelni materijal<br />kori&scaron;ćen kao eksperimentalni faktor; (3) izve&scaron;tajima koje su studenti eksperimentalnih<br />grupa imali obavezu da pi&scaron;u nakon obavljene nastave vokabulara kako bi na taj način<br />autorka dobila jasniju sliku i detaljnije podatke o sprovedenoj eksperimentalnoj<br />nastavi i (4) intervjuu koji je obavljen sa odabranim studentima iz eksperimentalnih i<br />kontrolnih grupa druge i četvrte godine (20 intervjua). Na ovaj način, istraživanjem<br />koje se oslanja na četiri izvora podataka, prikupljeni su detaljni podaci o pojavi koja<br />se istražuje, a time se obezbeđuje pouzdanost i validnost metodologije koja je<br />kori&scaron;ćena.<br />Rezultati istraživanja su analizirani kvantitativno i kvalitativno. Na osnovu<br />konačnih rezultata dobijenih analizom celokupnog materijala, može se zaključiti da je<br />uticaj verbalno-vizuelnog materijala sa sredstava vizuelnih komunikacija na usvajanje<br />vokabulara engleskog kao stranog jezika generalno pozitivan. Takođe, primećeno je<br />da je taj uticaj statistički značajan kod usvajanja značenja i pisanja reči, ali ne i kod<br />usvajanja oblika i manje-frekventnih reči. Iako su mi&scaron;ljenja i stavovi studenata o<br />značaju verbalno-vizuelnog materijala, kao i o sprovedenoj eksperimentalnoj nastavi<br />pozitivni, uočeno je da oni od svih strategija učenja vokabulara najređe koriste<br />strategije pamćenja koje podrazumevaju kori&scaron;ćenje verbalno-vizuelnog materijala.<br />Potencijal ovog istraživanja je u tome &scaron;to se daju predlozi za podučavanje vokabulara<br />engleskog kao stranog jezika sa upotrebom vi&scaron;e verbalno-vizuelnog materijala na<br />univerzitetskom nivou, sa ciljem da se pomogne studentima da &scaron;to lak&scaron;e i uspe&scaron;nije<br />usvoje nove reči, ali i u cilju postizanja kreativnijeg i zanimljivijeg okruženja u samoj<br />nastavi.</p> / <p>This thesis aims to explain the level and the importance of visual-verbal<br />material influence on EFL vocabulary acquisition. The previous studies on this topic<br />focus mainly on younger learners, while this thesis examines the research<br />phenomenon at the university level among English language and literature students.<br />The research is based on four data sources: (1) the questionnaire which was<br />completed by all the students (N=71) with the aim to provide general data of the<br />sample and to get the clearer picture about their thoughts and attitudes towards using<br />visual-verbal material in the classroom, as well as towards the importance and the<br />influence of visual communication on EFL vocabulary acquisition; (2) the test as a<br />part of the experiment with parallel groups, conducted with the second and the fourth<br />year students (N=41) where visual-verbal material was used as an experimental<br />factor; (3) the narratives which students of the two experimental groups were obliged<br />to write after vocabulary classes, in order to provide broad picture and more precise<br />data about the experimental classes, and (4) the interview with the selected students<br />from both year of study experimental and control groups (20 interviews). This kind of<br />research, based on these four data sources, was the way to collect the precise data<br />about the research phenomenon, and also to provide the reliability and the validity of<br />the used methodology.<br />The results of the research were analyzed quantitatively and qualitatively. On<br />the basis of the final results, it can be concluded that the influence of the visual-verbal<br />material on EFL vocabulary acquisition is generally positive. It is also noticed that the<br />influence on the acquisition of word meaning and spelling was statistically significant,<br />but the influence on acquisition of word form and low-frequency words was not<br />statistically significant. Although students&rsquo; attitudes towards the importance of visualverbal<br />material and conducted experimental classes are positive, it is noticed that<br />students very rarely use memory strategies (visual-verbal material usage). The<br />potential of this research lies in the prepositions of teaching EFL vocabulary at the<br />university level with more visual-verbal annotations, with the aim to help students in<br />easier and more successful acquisition of English language vocabulary, as well as in<br />order to help teachers in achieving more creative and more interesting surrounding for<br />EFL vocabulary classes.<br />&nbsp;</p>

<p>U disertaciji je izvršena karakterizacija mikrostrukture i mehaničkih osobina<br />nelegiranog austemperovanogi nodularnog liva (ADI materijala), kao i uticaja<br />mikrostrukture na prelaznu temperaturu u intervalu od -196 do +100&deg;C.<br />Utvrđeno je da mehaničke osobine ADI-ja zavise od morfologije ausferitne<br />mikrostrukture i količine zadržanog austenita, tj. parametara austemperovanja.<br />Na osnovu mehaničkih osobina utvrđen je i opseg procesiranja u skladu sa<br />standardima ASTM, ISO i EN. Zaključeno je da prelazna temperatura ADI<br />materijala zavisi od količine i stabilnosti zadržanog austenita. U višem<br />temperaturnom opsegu (iznad cca. -25&deg;C) dominantna je količina zadržanog<br />austenita, dok na nižim temperaturama, stabilnost. Visoka obogaćenost<br />ugljenikom, stabilnog zadržanog austenita sprečava stvaranje martenzita na<br />niskim temperaturama, a time i pojavu krtosti kod ADI-ja.</p> / <p>The object of this thesis was to characterize microstructure and mechanical properties<br />of the unalloyed ADI material (Austempered Ductile Iron). In addition, the influence of<br />microstructure on the ductile to brittle transition temperature (DBTT) by Charpy impact<br />test in temperature interval from 196 to +100&deg;C has been studied. The all properties<br />obtained depend on the morphology of microstructure and the amount of retained<br />austenite, i.e. on the austempering parameters. According to the mechanical properties<br />and standard requirements (ASTM, ISO and EN) the processing window has been<br />proposed, also. It was found that DBTT is influenced by amount and stability of retained<br />austenite. In upper temperature range (above cca. 25&deg;C) the most influence factor on<br />DBTT is amount of retained austenite, while at the lower temperatures the stability is<br />more prominent. Stability of high carbon retained austenite at lower temperatures<br />prevents transformation to martensite and thus the embrittlement of ADI.</p>

<p>U radu su predstavljeni rezultati&nbsp; ispitivanja biolo&scaron;ke&nbsp;<br />stabilnosti vode za piće primenom rotirajućih prstenastih reaktora (eng.&nbsp;<br />rotating annular reactor, RAR). Pomoću RAR praćen je uticaj odabranih&nbsp;<br />faktora na suspendovani i pričvr&scaron;ćeni mikrobni rast pri kontrolisanim&nbsp;<br />laboratorijskim uslovima koji su simulirali distributivne sisteme. Pored&nbsp;<br />toga, u cilju potpunog razumevanja biolo&scaron;ke stabilnosti vode za piće&nbsp;<br />izvr&scaron;eno je ispitivanje metoda za određivanje biodegradabilne frakcije<br />organske materije, BDOC i AOC test.</p><p>Poređenjem BDOC testova sa nativnom populacijom bakterija&nbsp;<br />pričvr&scaron;ćenom za pesak iantracit utvrđena je efikasnija primena biolo&scaron;kog&nbsp;<br />aktivnog peska. Primenom peska za inokulaciju uzorka, vrednost BDOC&nbsp;<br />u podzemnoj vodi sa teritorije srednjeg Banata iznosila je 1,27 mgC/l. U<br />ispitivanju AOC testa sa suspendovanim standardnim kulturama&nbsp;<br />Pseudomonas fluorescens P17 (ATCC 49642) i Spirillum sp. NOX&nbsp;<br />(ATCC 49643), AOC iskori&scaron;ćen od strane NOX je imao veću vrednost u&nbsp;<br />odnosu na P17, &scaron;to pokazuje da su karboksilne kiseline dominantan&nbsp;<br />supstrat za rast. Vrednost AOC u tretiranoj podzemnoj vodi iznosila 32&nbsp;<br />&mu;g acetat-C/l. Veće vrednosti BDOC ukazuju na prisustvo jedinjenja&nbsp;<br />veće molekulske mase u ovoj frakciji u odnosu na AOC frakciju&nbsp;<br />biodegradabilne organske materije.</p><p>U ispitivanju biostabilnosti podzemne vode sa teritorije srednjeg&nbsp;<br />Banatatokom tretmana, najveća količina biofilma je razvijena u RAR sa&nbsp;<br />ozoniranom vodom (13,30 CFU/cm²), &scaron;to potvrđuje efekte ozonizacije na&nbsp;<br />biodegradabilnost organske materije i ponovni rast mikroorganizama.&nbsp;<br />Tokom tretmana zabeleženo je variranje razvoja biofilma, pri čemu je&nbsp;<br />najmanji stepen rasta biofilma uočen u RAR sa vodom nakon GAC&nbsp;<br />filtracije (1,10 CFU/cm²).</p><p>Tokom mikrobne kolonizacije test-pločica RAR pri laminarnom i&nbsp;<br />turbulentnom protoku uočen je sličan trend rasta bakterija u biofilmu u sintetičkoj sme&scaron;i organskih i neorganskih nutrijenata. Međutim, tokom dominacije suspendovanog rasta u sistemu voda-biofilm pri neprotocnim uslovima, pona&scaron;anje biofilmova razvijenih pri protočnim (laminarnim i turbulentnim) uslovima je bilo različto. Uočen je manji udeo bakterija prisutnih u vodenoj fazi kod biofilma nastalim pri turbulentnom protoku u odnosu na veće oslobađanje ćelija iz biofilma nastalim pri laminarnim uslovima, nakon 48h 78% i 89% suspendovanih bakterija, redom. Ovi rezultati pokazuju da su biofilmovi razvijeni pri turbulentnom protoku snažniji, stabilniji &nbsp; i jače pričvr&scaron;ćeni nego pri laminarnom protoku.</p><p>Tokom praćenja sekundarne kolonizacije odvojenih ćelija biofilma&nbsp;<br />uočeno je da se primarni biofilm pona&scaron;a kao stalni rezervoar ćelija koje&nbsp;<br />su sposobne da zauzmu nove povr&scaron;ine vrlo brzo pri različitim&nbsp;<br />hidrodinamičkim uslovima. Brojnost bakterija u biofilmu razvijenom na&nbsp;<br />sekundarnim test-pločicama nakon 24 h iznosila je 32000&plusmn;1200&nbsp;CFU/cm^2&nbsp;<br />u odnosu na 16&plusmn;1 CFU/cm^2&nbsp;primarne test-pločice. Ustanovljen&nbsp;<br />je izraženiji potencijal kolonizacije novih povr&scaron;ina odvojenim želijama iz&nbsp;<br />primarnog biofilma koji je formiran pri turbulentnim uslovima u odnosu&nbsp;<br />na laminarne uslove.</p><p>Proces stvaranja biofilma na test-pločicama od nerđajućeg čelika&nbsp;<br />(SS), polivinilhlorida(PVC) i polietilena(PE) je bio vrlo sličan. Samo&nbsp;<br />debljina biofilma je bila veća na PE (4,0-5,5 kg/m³) nego na SS i PVC&nbsp;<br />test-pločicama (2,7-3,6 kg/m^3&nbsp;i 2,8-3,9 kg/m³, redom). Ustanovljen je&nbsp;<br />uticaj materijala cevi na rast biofilma u RAR snabdevanim vodom iz&nbsp;<br />distributivnog sistema grada Novog Sada, naročito za vreme početne faze&nbsp;<br />procesa. Biofilmovi formirani na različitim materijalima u RAR su uticali&nbsp;<br />na mikrobiolo&scaron;ki kvalitet vode, zavisno od njihove bakterijske gustine.&nbsp;</p><p>SEM analiza potvrdila je prisustvo biofilma na test-pločicama u&nbsp;<br />eksperimentima, ukazujući na uspe!nu primenu RAR u ispitivanju&nbsp;<br />biofilma i biostabilnosti vode za piće.</p><p>Rezultati dobijeni tokom ispitivanja ukazuju da se primenom&nbsp;<br />odabranih i optimizovanih, zavisno od cilja ispitivanja i vrste uzorka,&nbsp;<br />BDOC i AOC testova može efikasno definisati biolo!ka stabilnost vode&nbsp;<br />za piće. Pored toga, sistematski pristup odabiru odgovarajućih materijala&nbsp;<br />cevi, koji je zasnovan na pouzdanim testovima i definisanim&nbsp;<br />kriterijumima, može se primeniti u cilju osiguravanja kvaliteta vode sa&nbsp;<br />mikrobiolo&scaron;kog aspekta.</p><p>Ispitivanja su pokazala uspe&scaron;nu primenuRAR u simulaciji&nbsp;<br />mikrobnog rasta u cevima pri kontrolisanim laboratorijskim uslovima i&nbsp;<br />značaj istovremenog ispitivanja imobilisanog i suspendovanog rasta u&nbsp;<br />definisanom hidrodinamičkom sistemu.&nbsp; Primena RAR kao model biofilma je ukazala na njegov značaj u ispitivanju potencijala ponovnog naseljavanja povr&scaron;ina otkinutih delova i/ili pojedinačnih ćelija biofilma za uspostavljanje efikasne kontrole mikrobnih problema u distributivnim sitemima vode za piće.</p> / <p>This thesis presents theresults of investigation of drinking water biostability using the&nbsp; rotating annular reactor (RAR). The effects of selected factors on the suspended and attached microbial growth under controlled laboratory conditions that simulated the&nbsp;distribution systems were monitored using RAR. In addition, in order to completeunderstanding of the drinking water biological stability,&nbsp;methods for determining biodegradable organic matter fractions, BDOC&nbsp;and AOC methods were tested.</p><p>Comparing the BDOC tests with the native population of bacteria&nbsp;attached to sand and anthracite, a better application of biologically active&nbsp;sand was established. Using BDOC test with sand, the BDOC value in&nbsp;groundwater from the territory of the Central Banat (Republic of Serbia)&nbsp;was 1.27 mgC/L. In the investigation of AOC tests with standard&nbsp;<br />suspended culture of Pseudomonas fluorescens P17(ATCC 49642) and&nbsp;Sprillumsp. NOX (ATCC 49643), AOC utilized by NOX had a higher&nbsp;value compared to the P17, which shows that the carboxylic acid are&nbsp;dominant substrate for growth. The AOC value in the treated ground&nbsp;water was 32 &mu;g acetate-C/L. The higher BDOC values indicate the&nbsp;presence of higher molecular weight compounds in this fraction&nbsp;compared to the AOC biodegradable fraction of organic matter.&nbsp;</p><p>In the investigation of biostability during treatment of&nbsp;groundwater from the territory of the Central Banat (Republic of Serbia),&nbsp;the largest amount of biofilm was developed in the RAR with ozonated&nbsp;water (13.30 CFU/cm²), confirming the effects of ozonation on organic&nbsp;matter biodegradability and microbial regrowth. During treatment the&nbsp;<br />variation of biofilm development was detected and in the RAR with water after GAC filtration the lowest level of biofilm growth (1.10 CFU/cm²) was observed.&nbsp;</p><p><span style="font-size: 12px;">During the microbial colonization of the RAR test-coupons under&nbsp;</span><span style="font-size: 12px;">laminar and turbulent flow, the similar trend of growth of bacteria in the&nbsp;</span><span style="font-size: 12px;">biofilm in synthetic mixture of organic &nbsp;and inorganic nutrients was&nbsp;</span><span style="font-size: 12px;">observed. However, the higher numbers of immobilized bacteria under&nbsp;</span><span style="font-size: 12px;">the turbulent conditions in the same growth period (16 days) were&nbsp;</span><span style="font-size: 12px;">recorded. During the domination of suspended growth in water-biofilm system under &nbsp;non-flow conditions, the behavior of biofilms developed under flow (laminar and turbulent) conditions were different. There was a smaller proportion of bacteria present inthe aqueous phase of the biofilm formed under the turbulent flow over a larger release of cells &nbsp;from biofilms formed under laminar conditions, after 48h 78% and 89% of the suspended &nbsp;bacteria, respectively. These results indicate that biofilms developed under turbulent flow &nbsp;were stronger, more stable and more strongly attached than the ones under laminar flow.</span></p><p>During monitoring of the secondary colonization of the dettached&nbsp;biofilm cells, it was noted that the primary biofilm was a constant&nbsp;reservoir of cells that are able to occupy the new areas very quickly&nbsp;under different hydrodynamic conditions. The abundance of bacteria in&nbsp;the biofilm developed on the secondary test-coupons after 24 h was 32&nbsp;<br />000&plusmn;1200 CFU/cm² compared to 16&plusmn;1 CFU/cm²on the primary test-coupons. A stronger potential for colonization of new areas by dettached&nbsp;cells from the primary biofilm formed under the turbulent conditions in&nbsp;comparison to laminar conditions was found.&nbsp;</p><p>The biofilm formation processes on SS, PVC and PE test-coupons&nbsp;werevery similar. Only biofilm thickness was greater on the PE (4.0 to&nbsp;5.5 kg/m³) than the SS and PVC &nbsp;test-coupons (2.7 to 3.6 kg/m³ and 2.8 to&nbsp;3.9 kg/m³, respectively). There was a slight influence of pipe material on&nbsp;the biofilm growth, especially during the initial stages of the process.&nbsp;Biofilms formed on different materials in the RAR with water from the&nbsp;distribution system of the city of Novi Sad (Vojvodina, Republic of&nbsp;Serbia) have showed the influence on the microbiological quality of&nbsp;water, depending on their bacterial density.</p><p>SEM analysis confirmed the biofilm presence on test-coupons in&nbsp;the experiments, indicating the successful implementation of RAR in the&nbsp;examination of biofilm and drinking water biostability.&nbsp;</p><p><span style="font-size: 12px;">The results obtained during the investigations indicate that the&nbsp;</span><span style="font-size: 12px;">application of selected and optimized, depending on the test objective&nbsp;</span><span style="font-size: 12px;">and sample types, BDOC and AOC tests can effectively define the&nbsp; biological stability. In addition, a systematic approach for &nbsp;electing appropriate pipe materials, which is based on reliable tests and defined criteria, specific for the investigated drinking water distribution system can be applied to ensure &nbsp;he water quality from a microbiological point of view.</span></p><p>The investigations have shown the successful application of RAR&nbsp;in the simulation of microbial growth in the pipes under controlled&nbsp;laboratory conditions as well as the importance of simultaneous&nbsp;examination of immobilized and suspended growth under defined&nbsp;hydrodynamic system. Implementation of RAR as amodel biofilm&nbsp;indicated its importance in examining the potential resettlement area by&nbsp;dettached parts and/or individual biofilm cells to establish effective&nbsp;control of microbial problems in the drinking water distribution system.&nbsp;</p>