<p>U radu je izvršeno modeliranje i simulacija procesa obrade glodanjem sa predviđanjem temperature u zoni rezanja pomoću metode konačnih elemenata. Kao ulazni parametri obrade za model uzeti su brzina rezanja, korak i dubina rezanja a kao izlazna performansa temperatura u zoni rezanja. Kreirani model za simulaciju obrade glodanjem proveren je eksperimentalnim testiranjem sa istim parametrima obrade. Izvršena je analiza eksperimentalnih rezultata sa predloženim modelom. Rezultati ovog istraživanja su pokazali da se modeliranjem i simulacijom procesa obrade glodanjem može adekvatno predvideti temperatura u zoni rezanja.</p> / <p>The work explains process of modeling and simulation of milling predictive<br />temperature in the cutting zone by using the finite element method.The input<br />parameters for the processing model are cutting speed, feed and depth of a<br />cut. The temperature in the cutting zone was used as an output performance.<br />Designed model that simulates milling is checked by experimental testing<br />with the same machining parameters. The analysis of the experimental<br />results with the proposed model was carried out. Results of this study show<br />that the modeling and simulation of milling process can adequately predict<br />the temperature in the cutting zone.</p>

<p>U disertaciji je elaborirana mogućnost primene relaksirajućih otvora kod istiskivanja delova sa ozubljenjem u cilju smanjenja parametara procesa. Primenjena su dva modela deformisanja, kada je otvor u pripremku i kada je otvor u žigu. Metodom gornje granice izvr&scaron;ena je teorijska analiza procesa i kreirano re&scaron;enje na osnovu koga su određeni deformaciona sila, pritisak na žig i promena geometrije dela. Pomoću eksperimenta istiskivanja i numeričke simulacije procesa izvr&scaron;ena je verifikacija teorijskog re&scaron;enja. Teorijski, eksperimentalni i rezultati simulacije procesa su pokazali da primena relaksirajućih otvora na analizirane tipove ozubljenja dovodi do smanjenja deformacione sile i pritiska u procesu.</p> / <p>Possibility of flow relief openings applying in cold extrusion of gear-like elements in order to reduce the process parameters is elaborated in this thesis. Two different deformation models are analysed: when the opening is in the billet and when the opening is in the punch. Upper bound method was applied for the process analysis and determination of deformation force, punch pressure and change of part geometry. Extrusion experiment and numerical simulation of process are used for verification of theoretical solution. Theoretical, experimental and numerical results confirmed that application of flow relief openings enables reduction of deformation force and punch pressure in the process of gear-like elements extrusion.</p>

<p>Predmet istraživanja&nbsp; disertacije&nbsp; je&nbsp; prikaz&nbsp; koncepata&nbsp; elektronskog&nbsp;učenja,&nbsp; opis&nbsp; potrebe,&nbsp; motivacije&nbsp; i&nbsp; metodologije&nbsp; za&nbsp; obradu&nbsp; i&nbsp; konverziju&nbsp;postojećih&nbsp; tradicionalnih&nbsp; nastavnih&nbsp; materijala,&nbsp; bez&nbsp; obzira&nbsp; na&nbsp; fizički&nbsp; oblik&nbsp; i&nbsp;sadržaj,&nbsp; u&nbsp; savremene&nbsp; i&nbsp; aktuelne&nbsp; elektronske&nbsp; didaktičke&nbsp; objekte&nbsp; (learning&nbsp;objects).&nbsp; Ideja je da&nbsp; oni&nbsp; budu kreirani tako da mogu&nbsp; biti&nbsp; kori&scaron;ćeni,&nbsp; ako&nbsp; je&nbsp;moguće i vi&scaron;e puta, u sistemima za podr&scaron;ku elektronskom učenju.&nbsp;</p><p>Drugi osnovni predmet istraživanja je opis, definisanje&nbsp; i praktična provera&nbsp;metodologije&nbsp; za razvoj saradničkih i komunikacionih ve&scaron;tina&nbsp; studenata.&nbsp;Pri prelazu iz učionice u oblast elektronskog učenja&nbsp; one se&nbsp; zamenjuju&nbsp;elektronskim aktivnostima,&nbsp; standardnim&nbsp; i uobičajenim&nbsp; delom&nbsp; sistema za&nbsp;elektronsko&nbsp; učenje.&nbsp; Analizirana&nbsp; je&nbsp; primena klasičnih aktivnosti&nbsp; Web&nbsp; 2.0&nbsp;tehnologije: foruma, chat-sistema, Wiki i blog tehnologije,&nbsp; kao i&nbsp;metodologije za on-line zadavanje, re&scaron;avanje, pregledanje&nbsp; i ocenjivanje&nbsp;individualnih i timskih zadataka.</p><p>Konačno,&nbsp; data&nbsp; je&nbsp; sistematizacija&nbsp; metodologija&nbsp; upotrebe&nbsp; elektronskih&nbsp; nastavnih&nbsp;materijala i načini opisivanja meta-modelom. Prikazani su neki od postojećih alata&nbsp;za upotrebu u elektronskom učenju, a&nbsp; predložen&nbsp; je&nbsp; model i potencijalno korisni&nbsp;<br />alati&nbsp; za&nbsp; automatizaciju&nbsp; procesa&nbsp; konverzije&nbsp; nastavnih&nbsp; materijala&nbsp; koji&nbsp; bi olak&scaron;ali&nbsp;kori&scaron;ćenje u sistemima za podr&scaron;ku elektronskom učenju.</p> / <p>The research topic involves description of eLearning concepts,&nbsp;depiction of need, motivation and methodology for processing and&nbsp;conversion of existing traditional teaching materials, regardless of their&nbsp;physical form and content, into contemporary and up-to-date electronic&nbsp;teaching material, learning objects. The idea is that these learning&nbsp;objects are created&nbsp; in such a way that they can be used, if possible also&nbsp;reused, in some of the learning management systems.</p><p>The other primary research topic is the description, definition and&nbsp;practical testing of methodologies for the development of collaborative&nbsp;and communicative skills with students. Those skills are,&nbsp; as a part of the&nbsp;transfer from the classroom to&nbsp; the field of eLearning, substituted with&nbsp;electronic activities which are the standard and usual part of learning&nbsp;management systems. Within the thesis, application of typical activities of&nbsp;<br />so-called Web 2.0 technologies: forums, chat-systems, Wiki and blog&nbsp;technology, but also methodologies for on-line assigning, solving, audit,&nbsp;and assessment of &nbsp;individual and team assignments.</p><p>Finally,&nbsp; systematization of various methodologies of digital teaching&nbsp;material use is presented, together with the methods of their depiction by&nbsp;meta-model. Examples of&nbsp; currently existing tools&nbsp; available for eLearning&nbsp;are presented and a model is suggested, together with&nbsp; the&nbsp; potentially&nbsp;useful tools that might help in automatization &nbsp;of a process of&nbsp; conversion&nbsp;of teaching materials and their use in learning management systems.&nbsp;</p>

<p>Disertacija daje pregled novih i relevantnih istraživanja i stavova<br />u naučnoj zajednici na temu štamparskih formi i uticaja procesa<br />štampe na trošenje neštampajućih elemenata. U disertaciji je<br />ukazano na kontinualno praćenje topografskih promena<br />neštampajućih elemenata štamparskih formi kako bi se kontrolisao<br />period eksploatacije a time i proces reprodukcije. Takođe daje<br />prilog novim istraživanjima sa analizom velikog broja<br />eksperimentalnih uzoraka sa dobijenim izmerenim podacima i<br />odgovarajućim korelacijama i predstavlja napredak u shvatanju<br />mehanizma trošenja neštampajućih površina štamparskih formi i<br />njihov uticaj na tribološke promene u odnosu na strukturu osnove<br />aluminijuma i sloja aluminijum oksida.</p> / <p>Dissertation gives an overview of the current state, research and theories of<br />printing forms and influence of printing process on wearing of non-printing<br />elements within the science community. The dissertation points out the continuous<br />monitoring of topographic changes of printing form non-printing elements to control<br />the exploitation of a period of time and the process of reproduction. This work<br />contributes to new research with the analysis of large number of experimental<br />samples and calculated correlations and represents an advance in the<br />comprehension of the surface wear mechanism of printing form non-printing<br />elements and their influence on the tribological changes to the structure of the<br />base layer of aluminium and aluminium oxide.</p>

<p>U uvodnom delu doktorske disertacije opisuje se kompleksnost problematike kori&scaron;ćenja polimera za bazu zubne proteze, sa osvrtom na njihove op&scaron;te osobine, stepen biokompatibilnosti i njihove mehaničke karakteristike. Detaljno je opisana problematika ispitivanja stomatolo&scaron;kih materijala i napravljeno je poređenje i korelacija između in vitro i in vivo načina ispitivanja biokompatibilnosti. Drugi deo obuhvata ispitivanje čvrstoće polimera za bazu zubne proteze i analizu uticaja osobina materijala u odnosu na biolo&scaron;ku sredinu u kojoj obavljaju svoju funkciju, i u odnosu na sile kojima su tokom funkcije materijali izloženi. Cilj doktorske disertacije je utvrđivanje stepena biokompatibilnosti i mehaničkih karakteristika toplopolimerizujućih, hladnopolimerizujućih i termoplastičnih akrilata za bazu zubne proteze. Istraživanje je obuhvatilo 3 komercijalna materijala iz grupe akrilata, koji se razlikuju po hemijskom sastavu i načinu polimerizacije. Ispitivanje biokompatibilnosti rađeno je u in vitro i in vivo uslovima. Ispitivanje na ćelijskim kulturama obuhvatalo je dve ćelisjke linije (MRC 5 i L929) sa dva načina kontakta između ćelija i materijala (direktan, indirektan) i dva načina određivanja biolo&scaron;kog ishoda (MTT test, Agar difuzioni test). Istraživanje urađeno in vivo obuhvatalo je test subkutane implantacije, na animalnom modelu pacova, i test iritacije oralne sluzokože na animalnom modelu hrčka. Oba testa rađena su u skladu sa standardom ISO 10993. Cilj in vivo istraživanja bio je ispitivanje reakcije tkiva na implantirani materijal, računajući i zavr&scaron;nu integraciju ili dezintegraciju implantiranog materijala. Prednost in vivo istraživanja nalazi seu analizi uticaja materijala na sterilno živo tkivo, uz praćenje imunolo&scaron;ke reakcije, kao dopuna prethodnom istraživanju na ćelijskim kulturama. Dopunski deo in vivo ispitivanja biokompatibilnosti određen je prema kliničkoj upotrebi ispitivanih materijala, zbog čega je odabran test oralne iritacije sluzokože. Sluzokoža bukalne kesice sirijskog hrčka sastoji se od pločasto slojvitog epitela sa orožavanjem, &scaron;to je predstavljao dobar model za ispitivanje polimera za bazu zubne proteze, po&scaron;to zubna proteza naleže na sluzokožu nepca i rezidualnog alveolarnog grebena koja takođe orožava. Drugi deo disertacije obuhvatao je ispitivanje mehaničkih karakteristika, pri čemu su urađeni test zatezne čvrstoće, test savojne čvrstoće, test čvrstoće loma i mikrotvrdoće, uz dopunsku analizu pratećih parametara. Rezultati ispitivanja biokompatibilnosti pokazali su da su testovi biokompatibilnosti osetljivi na upražnjeni metodolo&scaron;ki postupak. Ispitivanjem na ćelijskim kulturama nisu utvrđene značajne razlike u citotoksičnosti između toplopolimerizujućih, hladnopolimerizujućih i termoplastičnih akrilata. Takođe, rezultati su se razlikovali u odnosu na tip ćelijske kulture i način provere biolo&scaron;kog ishoda, &scaron;to se slaže sa prethodnim navodima o kompleksnoj problematici njihovog međusobnog poređenja. Ispitivanjem biokompatibilnosti subkutanom implantacijom praćen je inflamatorni odgovor tkiva u vremenskom intervalu od 90 dana. Reakcija organizma na implantirani materijal posmatrana je kroz ćelijske i tkivne parametre, u skladu sa ISO 10993. Dodatno je urađena i analiza hrapavosti implantiranih materijala. Histolo&scaron;kom analizom utvrđena je razlika u inflamatornom odgovoru u odnosu na kori&scaron;ćeni materijal, kao i prema vremenskom intervalu implantacije. Test oralne iritacije sluzokože nije se pokazao kao dovoljno senzitivan za ispitivanje ovih vrsta materijala. Ispitivanjem mehaničkih karakteristika utvrđene su razlike između toplopolimerizujućih, hladnopolimerizujućih i termoplastičnih akrilata. Najveći stepen čvrstoće utvrđen je kod toplopolimerizujućih akrilata dok je najveća konzistentnost rezultata bila u grupi termoplastičnih akrilata. Prezentovano istraživanje predstavlja prvu detaljnu analizu biokompatibilnosti i mehaničkih karaktestistika polimera za bazu zubne proteze.</p> / <p>The introduction describes the complexity of use of denture base materials, with regard to their general characteristics, biocompatibility and mechanical properties. Issues related to the testing of dental materials is described in detail and comparison is made between in vitro and in vivo methods of biocompatibility testing. The second part further covers the determination of strength of previously used materials, in relation to biological environment in which their function is conducted and in relation to the influence of masticatory forces which can contribute to their mechanical failure. The aim of the presented research was to assess the degree of biocompatibility and mechanical properties of cold curing, hot curing and thermoformed denture base materials. The research included three denture base materials, which differed according to their chemical composition and polymerization protocols. The biocompatibility testing was carried out in in vitro and in vivo conditions. The in vitro experiments covered two different cell lines (MRC 5 human lung fibroblasts and L929 mouse fibroblasts) with two types of contact (direct, indirect) and two different types of quantification of biological outcome (MTT assay and Agar overley test). The in vivo assessment of biocompatibility covered the subcutaneous implantation test, on the animal model of Wistar rat, and oral mucosa irritation test, on the animal model of sirian hamster. Both tests were conducted according to the ISO 10993. The aim of the in vivo investigation was to evaluate tissue reactions to the implanted materials, including the final integration or disintegration of the tested materials. The advantage of in vivo investigation included the possibility of monitoring the materials influence on living tissues, with the analysis of imunological response as an addition to the previously conductedresearchon cell cultures. The supplemental part of in vivo investigation was chosen according to the clinical use of the tested materials, which included the oral mucosa irritation test.The mucosa of hamster buccal pouch consists of stratified squamos epithelium, which is considered to be an adequate replacement for the human denture supporting tissues, which also consist of the same type of epithelium. The second part of thesis includes the determination of mechanical properties of denture base materials. It consists of four types of tests: tensile strength test, bending strength test, fracture toughness test and microhardness tests, followed by the analysis of corresponding parameters. The results of the biocompatibility tests showed that the biological outcome of the applied method is highly depended on the methodological procedure. The investigation conducted in vitro, on two different cell lines, did not show significant difference in cytotoxicity between hot curing, cold curing and thermoformed denture base materials. Also, the results were influenced by the type of cell culture and the evaluation method of biological outcome, which agrees with the previous allegations about the complexicity of their mutual comparison. The subcutaneous implantation test covered the inflammatory response in the time period of 90 days. The organism reaction to the implanted material was determined through the cell and tissue parameters of organism response, evaluation of which was conducted according to the ISO 10993. Additionally, the surface roughness of the implanted specimens of materials was also measured. The inflammatory response of the ogranism was influenced by the type of the implanted material and the time interval of implantation. The oral mucosa irritation test has proven not to be sufficiently sensitive for testing of this type of materials. Testing of the mechanical properties od denture base materials, revealed the difference between the cold curing, hot curing and thermofomed denture base materials. The highest strength was observed in hot curing materials, while the highest consistency of the results was observed in thermoformed resins. The presented investigation presents the first detail analysis of the biocompatibility and mechanical properties of the denture base materials, and as such presents a novelty in the field of dental materials characterization.</p>

<p>Učenje o načelima postupka je jedno od karakteristika germanske procesualistike, pod čijim uticajem postaje i neodvojivi deo domaće doktrine. U teoriji se veoma rano se za oblast prikupljanja procesnog materijala formiraju dva antipodna načela &ndash; raspravno i istražno. Prvo podrazumeva da su samo stranke ovla&scaron;ćene da unose procesni materijal, odnosno da su samo one odgovorne za to. Drugo stavlja u dužnost sudu pribavljanje procesnog materijala i prebacuje odgovornost sa stranaka na njega.</p><p>Od promena u srpskom parničnom postupku koje su usledile 2004. g. tvrdi se da je raspravno načelo afirmisano, a dono&scaron;enjem Zakona o parničnom postupku iz 2011. g. i da je promenjen koncept parničenja u smislu uloge suda. On je sada pasivan, i gotovo neodgovoran na planu prikupljanja procesnog materijala. Predmet istraživanja u disertaciji je postojanje raspravnog načela u sada&scaron;njem srpskom parničnom postupku.</p><p>Rezultati istraživanja pokazuju da se ne može govoriti o raspravnom načelu kao važećem u srpskom parničnom postupku. Takav zaključak je, pre svega, uslovljen teoretskim određenjem pojma raspravnog načela i njegovog odnosa prema sudijskoj dužnosti pitanja. Raspravno načelo zaista podrazumeva da samo stranke unose procesni materijal u postupak i da u tom pogledu imaju slobodu, odnosno odgovornost. U tom smislu njegova nužna posledica su tri instituta: teret tvrdnje, priznanje tvrdnji koje vezuje sud i subjektivni teret dokazivanja. Međutim, ukoliko uz ova tri instituta postoji i sudijska dužnost pitanja, onda se odgovornost delom prebacuje i na sud, &scaron;to dovodi do postojanja sasvim drugog načela &ndash; ublaženog raspravnog načela.</p><p>Na osnovu rečenog, promene koje su se desile napu&scaron;tanjem načela materijalne istine, i to pre svega ukidanjem ovla&scaron;ćenja suda da izvodi dokaze po službenoj dužnosti, nisu dovele do uspostave raspravnog načela. Sud i dalje ima dužnost da postavljanjem pitanja ukazuje strankama na deficite procesnog materijala; presuda na osnovu tereta tvrdnje, kao i presuđenje uprkos nepredlaganju dokaza može da usledi samo ako sud prethodno ispuni svoju dužnost. Sud je i u srpskom postupku saodgovorni subjekat postupka, i to ne proizilazi samo iz redakcije ZPP, već je takav smisao u skladu sa vrednovanjima slobode i odgovornosti stranaka, sa ciljem postupka, i na kraju sa osnovnim ljudskim procesnim pravima zagarantovanim Ustavom.</p><p>Određenje da raspravno načelo nije važeće, već da je to ublaženo raspravno, utiče na shvatanje niza instituta koji se tiču procesa formiranja činjeničnog stanja,<br />a spram toga se i svi drugi instituti koji se tiču procesa formiranja činjeničnog stanja moraju prosuđivati.</p><p>Veoma važan deo istraživanja, koji je i prethodio zauzimanju stavova, je uporednopravno istraživanje fokusirano na germanski pravni krug &ndash; Nemačku i Austriju. S obzirom da su srpsko procesno pravo i dogmatika gotovo pod isključivim germanskim uticajem, bilo je potrebno da se temeljno istraži pitanje raspravnog načela u ovim sistemima. Rezultati ovog dela su pokazali da je ideja o raspravnom načelu koje podrazumeva pasivan i neodgovoran sud davno prevladana; upravo obratno, moderan germanski model postupka podrazumeva saodgovornost suda i stranaka.</p> / <p>The doctrine of civil litigation principles is one of the key characteristics of the Germanic procedural theory. Under its influence the doctrine of the principles grew into the essential part of the Serbian theory as well. The theory has rather early developed two conflicting principles with regard to responsibility for collecting the facts and and evidence &ndash; the principle of party control of facts and means of proof (Verhandlungsmaxime) and principle of investigation by the court (Untersuchungsmaxime). First one entails that the parties only can provide facts and means of proof in litigation; court can not render its judgment upon facts or proof which are not introduced by the parties. Second one implies a duty of the court to ascertain and clarify the facts; by the same token, court has responsibility to do so.<br />It is the common opinion that principle of party control over facts and means of proof is effectuated in Serbian civil litigation since legislative changes in 2004. Moreover, after the introduction of the new Civil Procedure Act in 2011it is widely accepted that the paradigm of litigation is radically changed so the court is now rather passive and almost without any responsibility for gathering facts and means of proof. The subject matter of this doctoral thesis is the existence of principle of party control of facts and means of proof in current Serbian civil litigation.<br />The results of analysis show that the principle of party control of facts and means of proof does not exists in Serbian civil litigation. This conclusion is first of all determined by dogmatic examination of the principle&rsquo;s notion. Indeed it signifies that only parties produce facts and means of proof, and in that sense that they have disposition and, accordingly, responsibility for that. By the same token, its necessary consequence are three institutes: burden of facts, binding effect of non disputed facts and burden of production of proof. However, if these three institutes exist with the court&rsquo;s parallel duty to provide hints and feedback, then the responsibility is shifted partly to the court, which results in existence of a new principle &ndash; principle of soften party control of facts and means of proof.<br />Regarding to what is said earlier, the changes which resulted in abandoning the principle of seeking of material truth, basically abrogating the court&rsquo;s obligation to take the proofs ex offo, did not lead to the creation of principle of party control of facts and means of proof. The court still has a duty to give hints and feebacks, i. e. to suggest to the parties that they clarify or supplement their pleadings; dismissing the claim or striking defense as insufficient due to the lack of factual pleadings or production of means of proof can take place only if the court previously fulfills its duty. The court is also in Serbian civil litigation jointly responsible procedural subject. That conclusion is not warranted only by interpretation of wording of the Civil Procedure Code&rsquo;s provision, but rather and predominantly by evaluation of party autonomy and responsibility in Serbian civil procedure, purpose of a civil procedure, and last but not least, by basic procedural constitutional rights.<br />The conclusion that the principle of party control of facts and means of proof does not exist and that its place is taken by the principle of softened party control has fundamental consequences on set of institutes which refer to the process of determination of facts. In that sense all these institutes are analyzed by the virtue of existing principle of Serbian civil procedure.<br />Particularly important part of the thesis, which indeed precedes the main part, is a comparative study of the Germanic legal systems &ndash; Germany and Austria. Regarding the fact that Serbian procedural law and doctrine was and still is under almost entirely Germanic influence, it was necessary to conduct a thorough analysis of these systems. Results show that the idea of principle of party control of facts and means of proof, i. e. idea of passive and unliable court is abendoned. Directly opposite, modern Germanic procedural model is distinguished by joint responsibility of court and parties.</p>

<p>U doktorskoj disertaciji razmatra se unapređenje konstrukcije magnetoreolo&scaron;ke disk kočnice sa ciljem povećanja vrednosti ukupnog kočnog momenta. Radi potpunog razumevanja međusobnog odnosa materijala i magnetskog polja na prvom mestu je izvr&scaron;eno utvrđivanje magnetskih svojstava materijala. Unapređenje konstrukcije je izvr&scaron;eno kroz vi&scaron;e iteracija i prototipova. Merenje vrednosti ukupnog kočnog momenta je podeljeno na merenje vi&scaron;e njegovih komponenti pri različitim vrednostima broja obrtaja i upravljačke struje namotaja.</p> / <p>In this thesis magnetorheological disk brake construction improvement is considered, with the goal to increase the overall braking torque value. For purposes of better understanding of material to magnetic field relationship, series of magnetic field testing were conducted. Construction improvement has been carried out through several iterations and different prototypes. Overall braking torque value measurements have been divided into several component measurements, utilizing different rotational speeds and coil control currents.</p>

<p>Strukturiranje elastomernih kompozita dodavanjem različitih vrsta nanopunila je dovelo do značajnog pobolj&scaron;anja njihovih primenskih svojstava, a samim tim i do povećanja njihove potencijalne primene kao pogodnih materijala za specijalne namene. U ovom radu, dobijene su dve grupe elastomernih hibridnih materijala za specijalne namene (na osnovu stirenbutadienskog elastomera i na osnovu termoplastičnih poliuretana).<br />U prvom delu istraživanja, veliki doprinos u razvoju industrije gume je postignut strukturiranju stirenbutadienskih nanokompozita primenom nanočestica punila silicijum(IV)oksida različitih morfolo&scaron;kih svojstava, dobijenih hidrotermičkom i termičkom obradom, primenom tri eksperimentalno modelovana punila silicijum(IV)oksida (dobijena taloženjem iz Na-vodenog stakla sa sumpornom kiselinom), kao i hibridnog punila (kombinacije čestica aktivne čađi i SiO₂ optimalnih svojstava). Izvr&scaron;ena je analiza uticaja strukture, povr&scaron;ine i povr&scaron;inske aktivnosti nanopunila na ojačanje elastomera, kao i provera koncepata, modela i teorija ojačanja na neumreženim i umreženim sistemima stirenbutadienskih elastomera ojačanih modifikovanim punilima SiO₂. Primenom mnogobrojnih metoda karakterizacije, sveobuhvatno je ispitan uticaj nanopunila na karakteristike me&scaron;anja, reolo&scaron;ka svojstva pripremljenih hibridnih nanokompozita, sposobnost umrežavanja u neumreženom materijalu, kao i na toplotna, dinamičko-mehanička i mehanička svojstva umreženih nanokompozita, radi projektovanja i optimizovanja sastava SBR hibridnih materijala za razvoj modelnog protektora sa optimalnim svojstvima za ekolo&scaron;ke ili &quot;zelene pneumatike&quot;. Drugi deo istraživanja je bio posvećen dobijanju segmentiranih poliuretanskih elastomernih nanokompozita primenom alifatičnih polikarbonatnih diola i nanočestica bentonita, koji nalaze primenu u medicini, građevinarstvu, u industriji name&scaron;taja i sportske opreme. Primenom mnogobrojnih metoda za karakterizaciju, ispitan je složen mehanizam uticaja tvrdih segmenata, termodinamičke nekompatibilnosti i prisustva nanočestica punila bentonita na strukturu i morfologiju, kao i na toplotna i dinamičko-mehanička svojstva pripremljenih poliuretanskih termoplastičnih elastomera. Dobijeni podaci o obrazovanju vodoničnih veza, termičkoj stabilnosti i termičkoj dekompoziciji, kao i o temperaturama prelaska u staklasto stanje i oblasti raskidanja čvorova fizičkih veza, predstavljaju značajan doprinos napretku strukturiranja poliuretanskih elastomera i nanokompozita na osnovu alifatičnih polikarbonatnih diola, i omogućavaju primenu ovih materijala za specijalne namene.</p> / <p>The structuring of elastomeric composites by addition of different nanofillers has led to a significant improvement of their end-use properties, and therefore, to their potential application as suitable materials for special applications. In this work, two types of elastomeric hybrid materials for special purposes were obtained (based on styrene-bustadiene elastomer or on segmented thermoplastic polyurethanes).<br />In the first part of the study, a major contribution to the development of the rubber industry was achieved by structuring styrene-butadiene nanocomposites, applying silica nanoparticles of various morphological properties: prepared by hydrothermal or thermal treatment, three experimentally prepared SiO2 fillers (obtained by precipitation from sodium silicate with sulfuric acid), as well as a hybrid filler (combination of carbon black and SiO2 fillers with optimal properties). The analysis of the influence of the nanoparticles structure, surface and surface activity on the reinforcment of SBR elastomers, as well as the verification of concepts, models and reinforcement theories on non-cross-linked and cross-linked systems of styrene-butadiene nanocomposites was performed. Using the numerous characterization methods, the influence of nanofillers on the mixing characteristics, the rheological properties of the prepared hybrid nanocomposites, as well as the thermal, dynamic-mechanical and mechanical properties of cross-linked SBR nanocomposites was studied, in order to design and optimize the composition of SBR hybrid materials for development of environmental friendly or &quot;green&quot; tyre protector model.<br />The second part of the research was devoted to the preparation of segmented polyurethane elastomeric nanocomposites using aliphatic polycarbonate diols and bentonite nanoparticles, that have found the significant application in the medicine, construction, the furniture and sports equipment industry. Applying numerous characterization methods, a complex mechanism of the influence of the hard segments, thermodynamic incompatibility and the presence of bentonite filler on the structure and morphology, as well as on the thermal and dynamic-mechanical properties of the synthesized thermoplastic elastomers was studied. The obtained data on the hydrogen bonds formation, thermal stability and thermal decomposition, as well as the glass transition temperature and physical crosslink disruption temparature range, makes a significant contribution to the progress in structuring of polycarbonate-based polyurethane elastomers and their hybrid materials, and improves their potential applications for the special purposes.</p>

<p>Istraživanja prikazana u disertaciji imala su za cilj razvoj monotonih modela deformisanja u cilju njihove primene za određivanje dijagrama granične deformabilnosti. Kombinacijom različitih geometrija uzoraka, geometrije alata i triboloških uslova razvijeni su monotoni modeli deformisanja koji su promenjeni za određivanje dijagrama granične deformabilnosti.</p> / <p>Research presented in this dissertation was conducted in order to develop monotonic forming processes suitable for determination of forming limit diagram. Combining different geometries of billets as well as tools and friction conditions monotonic models are developed and applied for determination of forming limit diagram.</p>

<p>Rad,Edukativni i op&scaron;ti model kritičnih protoka materijala PD - Precedence Diagramming Structure, predstavlja integralni deo teorijskih i eksperimentalnih istraživanja vezanih za razvoj stohastičkih mreža PD-modela iz operacionih istraživanja, kao i modela za odgovarajuću edukaciju kadrova iz oblasti mrežnog upravljanja tokovima materijala u ma&scaron;inogradnji. U tom smislu u radu su razvijeni i re&scaron;avani, putem analitičkih i numeričkih metoda, sledeći modeli:</p><ul><li>Mrežni PD-model sa jednim kritičnim tokom.</li><li>Mrežni PD-model sa isključivo autonomnim (paralelnim) kritičnim tokovima.</li><li>Op&scaron;ti model sa varijantom kritičnih tokova autonomno-unijatnog tipa.</li><li>Edukativni model za efikasno re&scaron;avanje postavljenih problema upravljanjatokovima materijala u pojedinačnoj proizvodnji.</li><li>Modeli za vrednovanje metoda i postupaka iz ovih oblasti operacionih istraživanja, kao i samog edukativnog modela, na bazi razvijenih kvantitativnih i kvalitativnih kriterijuma.</li></ul><p>Ovim istraživanjem stvorene su određene podloge za dalji rad u predmetnom području, posebno sa stanovi&scaron;ta neinvesticionog povećanja efekata materijalne proizvodnje, putem primene razvijenih opercionih modela i edukativnih metoda za njihovo re&scaron;avanje.</p> / <p>The paper &quot;THE EDUCATIVE AND GENERAL MODEL OF THE CRITICAL MATERIAL FLOWS, PD-PRECEDENCE DIAGRAMMING STRUCTURE&quot; makes the integral part bof the theoretical and experimental researches connected for the development of the stochastic network PD - models of the opertions research, as well the models for the appropriote personal cadres edu cation in the field of network control of materijal flows in production of machinery. In the paper are also developed and solved, by analytic and numeric methods, the next models:</p><p>* The network PD-model with one critical flow.</p><p>* The network PD-model with excusively autonomus (parallel) critical flows.</p><p>* The general model with the variant of the critical flows of the autonomus -uniate type.</p><p>* The educative model for the effective solving of the stated problems of the material flows control in isolated production.</p><p>* The models and methods valuation of these fields of the operations researches, as well the educative model itself on the basic of the developed quantative and qualitative criteria.</p><p>With these researches are created the defined bases for further work in the subject field, particularly from the attitude of the noninvestment increasing of the effects of the materijal production, using the developed operations models and the educative models for their solving.</p>