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The aim of this paper is to examine the metrological characteristics of some of the most commonly used coordinate measurement systems in industry in a case study of the flatness error. The accuracy and measurement uncertainty of the coordinate measuring machine with contact probe, point by point mode and scanning mode, and with non - contact probe, then performance measuring arm, optical scanner and finally industrial computed tomography were analyzed. In order to exclude factors that affect the accuracy of measurement and measurement uncertainty, and are not part of the hardware structure of the CMS, the experiment was conducted on a reference workpiece and an independent software solution was used to estimate the error of flatness. The accuracy of measuring systems was determined as the difference between the reference value and the mean value of repeated measurements and the measurement uncertainty was determined according to the instructions for estimating the measurement uncertainty GUM. The results of the research showed high metrological performance of the coordinate measuring machine and the optical scanner for this measuring task. Also, it was found that industrial computed tomography gives a very large measurement error and that the measurement uncertainty is very difficult to determine.

U doktorskoj disertaciji je realizovano ispitivanje revitalizacije, parametara sagorevanja i emisije otpadnih transformatorskih i motornih ulja, kao i njihovih dizel mešavina. Dobijeni eksperimentalni rezultati ukazuju da se nakon revitalizacionog tretmana značajno poboljšavaju izolaciona svojstva transformatorskog ulja, što je veoma važno za bezbedan rad transformatora, zaštitu životne i radne sredine. Pored toga, rezultati eksperimentalnog ispitivanja procesa sagorevanja ukazuju da se otpadna transformatorska i motorna ulja i njihove mešavine sa dizelom mogu koristiti kao gorivo u generatorima toplote male snage i u raznim granama procesne industrije, te mogu smanjiti probleme u vezi sa zaštitom životne sredine., The doctoral thesis cover the testing of revitalization, combustion parameters and emissions of waste transformer and motor oils, as well as their diesel mixtures. The experimental results obtained indicate that after the revitalization treatment, the insulating properties of the transformer oil are significantly improved, which is very important for the safe operation of transformer, environmental protection and work environment. In addition, the results of an experimental test of the combustion process indicate that waste transformer and motor oils and their mixtures with diesel can be used as fuel in low power heat generators and in various branches of the process industry, and can reduce environmental issues.

Kreiranje 3D modela i njihova vizuelizacija postali su sastavni deo procesa razvoja novih ili redizajniranja postojećih proizvoda. U ovom istraživanju pažnja je posvećena rešavanju problema 3D digitalizacije kod blisko-predmetne fotogrametrije zasnovane na određivanju strukture iz kretanja, na površima bez karakterističnih obeležja primenom projektovanja sintetički generisanih slika u vidu svetlosnih tekstura. Akcenat je stavljen na generisanje novih sintetičkih slika koje imaju izraženu vizuelnu teksturu, njihovu evaluaciju i primenu na objektima sa monotonim vizuelnim površima sa ciljem podizanja ukupne tačnosti rekonstruisanih 3D modela. Verifikacija primene sintetičkih slika i njihovih svetlosnih tekstura sa aspekta geometrijske i dimenzione tačnosti je realizovana primenom računarom podržane inspekcije (CAD inspekcije)., The creation of 3D models and their visualization have become an integral part of the process of developing new or redesigning existing products. In this research, attention was paid to solving the problem of 3D digitization in close-range photogrammetry based on the structure from motion on surfaces without characteristic features by designing synthetically generated images in the form of light textures. An accent is placed on the generation of new synthetic images that have a pronounced visual texture, their evaluation, and application on objects with monotonous visual surfaces with the aim of raising the overall accuracy of reconstructed 3D models. The verification of the application of synthetic images and their light textures from the aspect of geometric and dimensional accuracy was realized through the use of computer-aided inspection (CAI inspection).

Kompjuterizovana tomografija (CT) je u poslednje vreme ušla na velika vrata sa razvojem industrijskih CT sistema, usled njene primene u različitim oblastima, a uveliko ulazi i u polje koodinatne metrologije. Zbog karakterizacije objekata sačinjenih od različitih materijala (najčešće metala i plastike), javljaju se određeni problem u vidu nastanka artefakata kod rezultata dimenzionalnih merenja. Istraživanja koja su sprovedena u ovoj doktorskoj disertaciji se bave problemom redukcije uticaja tih artefakata i segmentacije 2D snimaka. Razvijen je novi model koji je baziran na primeni hibridne metode gde je izvršena kombinacija dve metode za obradu slike, a to su fazi klasterizacija i rast regiona. Aksenat je stavljen na primeni ove hibridne metode radi dobijanja tačnijih rezultata segmentacije, što direktno utiče i na rekonstrukciju dimenzionalno tačnijih 3D modela., Computed tomography (CT) has recently entered a large door with the development of industrial CT systems, due to its application in many different areas, and it is already entering the field of coordinate metrology. Due to its ability to non-destructively characterize objects made of different materials (typicaly metals and plastics), a certain problem arises in the form of artefacts that are present in the results. Research carried out in this dissertation deals with the problem of reducing the impact of these artefacts and the 2D image segmentation. A new model was developed based on the application of the hybrid method where a combination of two methods for image processing was performed, which are fuzzy clustering and region growing. The accent is emphasized in the application of this hybrid method in order to obtain more accurate segmentation results, which directly affects the reconstruction of dimensionally more accurate 3D models.

Istraživanje u okviru doktorske disertacije obuhvata uzorkovanja inhalativne frakcije praškastih materija generisane u zubotehničkoj laboratoriji i procesom brušenja čelika EN 90MnCrV8, primenu savremenih metodologija uzorkovanja, analizu uzorka laserskom difrakcijom i analizom slike, zasnovanom na mikrografijama skenirajućeg elektronskog mikroskopa i statističku obradu podataka. Osnovni cilj istraživanja je razvoj funkcionalnog modela za evaluaciju rezultata merenja karakteristika praškastih materija, koji je obuhvatio identifikaciju, procenu i vrednovanje karakteristika prahova, u cilju unapređenja tačnosti rezultata u vezi sa karakterizacijom čestica. Složena geometrija čestica je ispitana analizom 14 parametara, 6 koji definišu veličinu i 8 parametara koji opisuju morfološke karakteristike, upotrebom dva softvera za analizu slike. Dobijeni rezultati obrađeni su primenom metode analize glavnih komponenti i hijerarhijske klaster analize, čime se prevazišao problem subjektivnog prilaza i izvršila redukcija i selekcije reprezantativnih parametara na osnovu kojih se može dovoljno dobro definisati i okarakterisati uzorak., Тhis PhD thesis presented the development of the functional model for evaluation оf measuring results of powder materials’ characteristics, which involved the identification, assessment and evaluation of particles characteristics, in order to improve the accuracy of the results. Sampling of inhalation fraction of the powder materials’ was done in the dental laboratory and grinding process of the EN 90MnCrV8 steel. Particle analysis was performed whit laser diffraction and image analysis based on micrographics from scanning electron microscopy and data were statistically analyzed. The complex particle geometry was examined by analyzing 14 parameters, 6 which define the size and 8 parameters that describe the morphological characteristics, using two image analysis software. To deal with a large number of the numerical parameters used to characterise the particle geometry and the nonlinear relationships among these parameters, principal component analysis (PCA) and hierarchical cluster analysis (CA) algorithm was applied to identify representative numerical descriptors within each group.

U radu se proučava uticaj parametara mikroklime, buke i osvetljenja na toplotni osećaj i toplotni komfor u radnoj sredini. Između čoveka i njegovog okruženja postoji stalna interakcija, koja može uzrokovati fiziološke poremećaje u organizmu. U okviru rada, prikazane su teorijske osnove parametara mikroklime, buke i osvetljenja, kao i njihov teorijski uticaj na generisanje i razmentu toplotne energije između čoveka i okoline. Rad obuhvata istraživanje međuzavisnosti proučavanih parametara, toplotnog osećaja i toplotnog komfora čoveka na radnom mestu u poziciji stajanja., This paper examines the influence of the parameters of microclimate, noise and lighting on the thermal sensation and thermal comfort in the working environment. There is a constant interaction between a person and his environment, which can cause physiological disorders in the organism. In the framework of this paper, the theoretical bases of the parameters of microclimate, noise and lighting, as well as their theoretical influence on the generation and exchange of heat energy between person and environment are presented. The paper encompasses research on the interdependence of the parameters studied for thermal sensation and the thermal comfort of a person at the workplace in a standing position.

Koordinatne merne mašine (KMM) su dominantni merni instrumenti u dimenzionalnoj metrologiji. NJihovom upotrebom se može izmeriti bilo koja makro tolerancija označena na tehničkoj dokumentaciji. Tolerancija ravnosti je često prisutna u cilju izvršenja zahtevanih funkcionalnih zahteva radnog predmeta. Istraživanja sprovedena u ovom radu se bave problemom procene greške ravnosti merene na KMM zasnovane na metodi minimalne zone i procene merne nesigurnosti za ovaj merni zadakat. Aksenat je stavljen na primeni Monte Karlo metode kao simulacionog alata za procenu merne nesigurnosti. Razvijena je nova metodologija za procenu greške ravnosti kao i simulacioni model za procenu merne nesigurnosti za ovaj merni zadatak., Coordinate measuring machines (CMMs) are dominant measuring instruments in dimensional metrology. These machines can measure any macro-tolerance indicated in the technical documentation. Flatness tolerance is often present with the aim of completing the needed functional requirements of a workpiece. The investigation conducted in this paper considers the problem of assessing the flatness error measured on a CMM based on the minimum zone method and on the method of evaluating measurement uncertainty for this measuring task. The emphasis is on the use of Monte Carlo method as a simulation tool for evaluating measurement uncertainty. A new methodology for assessing the flatness error has been developed, as well as a simulation model for evaluating measurement uncertainty for this measuring task.

Proces glodanja tvrdih (kaljenih) čelika, vretenastim loptastim glodalima, najčešće se primenjuje u operacijama završne obrade kompleksnih površina. Modelovanje ovog procesa i optimizacija njegovih parametara su veoma važni, kao pomoć za razumevanje samog procesa tako i za rešavanje praktičnih problema. Za modelovanje izlaznih performansi procesa obrade i nalaženje optimalnih vrednosti ulaznih parametara, korišteno je nekoliko klasičnih i prirodom-inspirisanih metoda. Od klasičnih metoda modelovanja i optimizacije, u radu su primenjene: metodologija odzivne površine-RSM, Taguči metoda i Taguči metoda sa sivom relacionom analizom. Korištene prirodom-inspirisane metode modelovanja i optimizacije su: genetski algoritam–GA, sivi vuk optimizer–GWO i nedominantno sortirajući genetski algoritam II–NSGA II. Dobijeni pouzdani matematički modeli izlaznih performansi procesa obrade i optimalni ulazni parametri obrade, potvrđuju opravdanost primene svih navedenih metoda u procesu glodanja vretenastim loptastim glodalima tvrdih (kaljenih) čelika. Posebno treba izdvojiti rezultate dobijene pomoću metode sivi vuk optimizer–GWO. Ova prirodom-inspirisana metoda je potpuno nova metoda i do sada nije bilo literaturnih informacija o mogućnostima njene primene u procesima obrade rezanjem., The ball end milling process of hard (hardened) steel, is usually applied in the finishing operations of machining comlex surfaces. Modeling of this process and optimization of its parameters are very important as an aid to understanding the processes and to solve practical problems. Several classic and nature-inspired methods were used for modeling of the output process performances and finding the optimal values of input parameters. From traditional methods of modeling and optimization Response Surface Methodology-RSM, Taguchi method and Taguchi method with Gray Relational Analysis, and nature-inspired methods of modeling and optimization Genetic Algorithm-GA, Gray Wolf Optimizer-GWO and Nondominant Sorting Genetic Algorithm II- NSGA-II, were applied in the paper. Reliable mathematical models of the output process performances and the optimal input parameters, confirm the validity of the application of these methods in the process of ball end milling hard (hardened) steel. The results obtained by the method of the Gray Wolf Optimizer-GWO should be particulary noted. This nature-inspired method is quite a new method, and so far there was no literature information on the possibilities of its application in the cutting processes.

U okviru disertacije izvršena je identifikacija ključnih hemijskih toksiĉnih supstanci poreklom iz higijenskih sredstava i njihove ambalaţe na životnu sredinu. Spektrofotometrijskom metodom izvršena je analiza sadržaja fosfora u praškastim detergentima, komunalnim otpadnim vodama Niškog kanalizacionog sistema i u reci Nišavi. Nakon proračuna sadržaja fosfora izvršena je procena količine ukupnog fosfora generisanog iz higijenskih sredstava, a koji moţe da ima izrazito negativan uticaj na životnu sredinu. Teorijska saznanja i eksperimentalni podaci omogućuju optimalno upravljanje hemijskim toksičnim supstancama iz higijenskih sredstava u skladu sa važećim zakonskim propisima i dostignutim naučnim saznanjima., This dissertation presents the identification of key toxic chemicals originating from hygiene and cleaning products and their packaging and the assessment of their environmental impact. The research involves a spectrophotometric analysis of phosphorus content in powder detergents, in municipal sewage from the City of Niš sanitary sewer, and in the Nišava river. Calculation of phosphorus content is followed by the assessment of the total amount of phosphorus generated from hygiene and cleaning products, which can have considerably negative environmental impact. Theoretical findings and experimental data allow optimal management of toxic chemicals from hygiene and cleaning products in compliance with current legislation and scientific knowledge.

Background/Aim. Dental impressions present a negative imprint of intraoral tissues of a patient which is, by pouring in gypsum, transferred extraorally on the working cast. Casting an accurate and precise working cast presents the first and very important step, since each of the following stages contributes to the overall error of the production process, which can lead to inadequately fitting dental restorations. The aim of this study was to promote and test a new model and technique for in vitro evaluation of the dental impression accuracy, as well as to asses the dimensional stability of impression material depending on the material bulk, and its effect on the accuracy of working casts. Methods. Impressions were made by the monophasic technique using the experimental master model. Custom trays with spacing of 1, 2 and 3 mm were constructed by rapid prototyping. The overall of 10 impressions were made with each custom tray. Working casts were made with gypsum type IV. Measurement of working casts was done 24 h later using a coordinate measuring machine. Results. The obtained results show that the working casts of all the three custom trays were in most cases significantly different in the transversal and sagittal planes in relation to the master model. The height of abutments was mainly unaffected. The degree of convergence showed certain significance in all the three custom trays, most pronounced in the tray with 3 mm spacing. Conclusion. The impression material bulk of 1-3 mm could provide accurate working casts when using the monophasic impression technique. The increase of the distance between abutment teeth influences the accuracy of working casts depending on the material bulk., Uvod/Cilj. Otisak predstavlja negativ intraoralnih tkiva, čijim se izlivanjem u gipsu njihova morfologija prenosi ekstraoralno na budući radni model. Sa laboratorijskog aspekta izrade zubnih nadoknada, izlivanje tačnog i preciznog radnog modela predstavlja prvi i veoma bitan korak, pošto svaka sledeća faza doprinosi daljem povećanju greške tokom izrade, što za krajnji ishod može imati neodgovarajuću zubnu nadoknadu. Cilj istraživanja bio je da se ispitaju novi model i tehnika za in vitro procenu preciznosti zubnih otisaka, kao i da se odredi uticaj količine otisnog materijala na dimenzionu stabilnost otisaka i preciznost izrade radnih modela. Metode. Za uzimanje otisaka korišćena je monofazna tehnika otiskivanja. Individualne kašike sa međuprostorom od 1, 2 i 3 mm napravljene su aditivnom tehnologijom za brzu izradu prototipova. Sa svakom kašikom napravljeno je po 10 otisaka. Radni modeli izlivani su u gipsu tipa IV. Merenje radnih modela vršeno je nakon 24 sata na koordinatnoj mernoj mašini. Rezultati. Rezultati pokazuju da radni modeli napravljeni pomoću sve tri individulane kašike u transverzalnoj i sagitalnoj ravni značajno odstupaju od glavnog dela modela. Visina patrljaka je u većini slučajeva bila kao na glavnom modelu. Stepen konvergencije pokazao je određena odstupanja samo kod kašike sa međuprostorom od 3 mm. Zaključak. Monofazna tehnika otiskivanja i otisni materijal debljine od 1 do 3 mm obezbeđuju izradu preciznih radnih modela. Rastojanje između zubnih patrljaka utiče na preciznost izrade radnih modela u zavisnosti od količine otisnog materijala.

The paper presents some aspects of the novel integrated system, procedure for fabrication of metal substructure of metal-ceramic crowns. The results been shown that the CAD/CAE/RP technology integration presented in this paper can be fully applied to casting metal substructures. The substructure fabricated in this way, confirm the reduction of the total manufacturing time, with an increase in the percentage of high quality castings that use integrated system.

Introduction: Traumatology of the maxillofacial region represents a wide range of different types of facial skeletal injuries and encompasses numerous treatment methods. Application of computer-aided design (CAD) in combination with rapid prototyping (RP) technologies and three-dimensional computed tomography techniques facilitates surgical therapy planning for efficient treatment. Objective: The purpose of this study is to determine the efficiency of individually designed implants of poly-DL-lactide (PDLLA) in the reconstruction of blowout fractures of the orbital floor. Methods: In the course of a surgical treatment, individually designed implants manufactured by CAD/RP technologies were used. Preoperative analysis and postoperative monitoring were conducted to evaluate the successfulness of orbital floor reconstruction using customized PDLLA implants, based on: presence of diplopia, paresthesia of infraorbital nerve, and presence of enophthalmos. Results: In 6 of the 10 patients, diplopia completely disappeared immediately after surgical procedure. Diplopia gradually disappeared after 1 month in 3 patients, whereas in 1, it remained even after 6 months. In 7 patients, paresthesia disappeared within a month after surgery and in 3 patients within 2 months. Postoperative average Orbital volume (OV) of the injured side (13.333 +/- 3.177) was significantly reduced in comparison with preoperative OV (15.847 +/- 3.361) after reconstruction of the orbital floor with customized PDLLA implant (P lt 0.001). Thus, average OV of corrected orbit was not different compared with the OV of the uninjured orbit (P = 0.981). Conclusions: Reconstruction of blowout fractures of the orbital floor by an individually designed PDLLA implant combined with virtual preoperative modeling allows easier preoperative preparation and yields satisfactory functional and esthetic outcomes.

U doktorskoj disertaciji je razmatran uticaj čvrstih čestica mirkonskih razmera na kritične radne performanse kontaktnog para klip-cilindar kao tipa kontakta koji je najzastupljeniji u hidrauličkim komponentama. Prema konceptualnom modelu je izvedena eksperimentalna instalacija na kojoj, za različite koncentracije čvrstih čestica i određeni broj radnih ciklusa je ispitivan intenzitet habanja, pad pritiska i veličina zapreminskih gubitaka proticanja kroz zazor. Nad skupom prikupljenih eksperimentalnih podataka je izvršena analiza i modelovanje funkcija koje opisuju ponašanje posmatranih veličina., This doctoral dissertation analyzes the influence of microscale solid particles on the the critical operational performances of the most common type of tribo-couples in power hydraulic components. According to the conceptual model, experimental installation was made. For different solid particles concentration levels and predefined number of working cycles, experimental installation was used to examine intensity of wear, pressure drop and volumetric efficiency – fluid loss trough the clearance. On the basis of experimental data set was carried out analysis and modeling of functions that describe the behavior of the observed parameters.

U disertaciji se prikazuje modularni sistem za projektovanje alata za injekciono presovanje plastike. Analizirani su različiti prilazi u projektovanu alata. Prikazana je koncepcija i funkcionisanje razvijenog sistema. Verifikacija sistema je izvršena na konkretnim plastičnim proizvodima. Na kraju su dati odgovarajući zaključci i mogući pravci budućih istraživanja., The dissertation shows the development of the modular system for mold design for plastic injection molding. Different approaches were analyzed in the field of mold design. The concept and functioning of the developed modular system is presented. Validation of the proposed system is made with the specific plastic parts. At the end the appropriate conclusions and possible directions for future research are given.

U okviru ovog rada navode se rezultati sprovedenih istraživanja na četvorogodišnjem projektu TR35007 koji zajednički realizuju Mašinski fakultet Univerziteta u Beogradu, Fakultet tehničkih nauka Univerziteta u Novom Sadu i kompanija Ikarbus iz Beograda. Ovaj projekat finansijskih podržava Ministarstvo prosvete i nauke u okviru četovorogodišnjeg ciklusa istraživačkih projekata za tehnološki razvoj, od 2011. do 2014. godine. Prvo se navode istraživački okvir projekta, osnovni ciljevi koji postavljeni pred istraživački tim i organizacija projekta koja je izvedena po modelu radnih paketa. U drugom delu rada navode se osnovni rezultati ostvaranih u prvoj istraživačkoj godini, sa odgovarajućim opisom i osnovnim detaljima tehničke i organizacione prirode.