Metod konfigurisanјa upravljačkog sistema otvorene arhitekture rekonfigurabilnog robota za obradu

U radu je prikazan jedan metod konfigurisanja/rekonfigurisanja upravlјačkog sistema otvorene arhitekture rekonfigurabilnih robota za obradu. Na primeru EMC2 upravlјačkog softvera otvorene arhitekture su posredstvom dijagrama za modelovanje dinamičkih procesa definisane aktivnosti sistemintegratora/korisnika u procesu konfigurisanja/rekonfigurisanja upravlјačkog sistema, i uspostavlјene su relacije između softverskih i hardverskih komponenata upravlјanja

Lathe tool life research in production environment during the orthogonal cutting

Obrada metala struganjem je jedan od najvažnijih proizvodnih procesa zato što pripremci dobijeni livenjem, kovanjem ili nekim drugim metodama obrade zahtevaju naknadnu obradu rezanjem kako bi se dobio finalni proizvod. U ovom radu, postavljen je nov model ortogonalnog rezanja koji pored sila za formiranje strugotine obuhvata i dodatne sile koje se javljaju usled trenja između leđne površine alata i obrađene površine – upotpunjen Merčantov model sila. Model sila rezanja obuhvata dva stanja alata: idealno oštar alat sa pripadajućim silama za formiranje strugotine i alat sa dozvoljenom širinom habanja na leđnoj površini sa porastima komponenata sila rezanja koji nastaju usled trenja između alata i obratka. Sile za formiranje strugotine i dodatne sile postavljene su tako da se na efikasan način može odrediti ugao trenja između leđne površine alata i obrađene površine što je od izuzetne važnosti za određivanje tangencijalnog napona na leđnoj površini alata, kao i porasta komponenata otpora rezanja. Na ovaj način se tačnije predviđa sila rezanja. U okviru disertacije razvijen je matematički model koji predviđa postojanost strugarskog noža u proizvodnim uslovima uzimajući u obzir korak, brzinu rezanja i širinu pojasa habanja leđne površine alata. Izvedena eksperimentalna istraživanja potvrdila su autentičnost postavljenog matematičkog modela, pri čemu se vrednosti dobijenih rezultata nalaze u okviru standardnih devijacija.Turning is one of the most important manufacturing operations because parts manufactured by casting, forming or other shaping process often require a further metal cutting operation before product is ready for use. In this paper, the orthogonal cutting force model is proposed comprising forces due to friction in addition to the forces for chip formation – completed Merchant’s force model. Cutting force model includes two tool conditions: perfectly sharp tool with accompaying forces for chip formation and tool with maximum permissible flank wear with accompaying forces generated due to the friction between tool flank and workpiece. Based on cutting force relationships between the wear (friction) forces and forces for chip formation, it is possible to analytically predict friction angle between the tool and workpiece. From pure geometrical relationships between forces the equation for the friction angle between the tool flank and workpiece can be derived, which is of the great importance in determining tangential stress at the tool flank surface and forces due to wear. In this way cutting forces are more accurately predicted. This work presents the development of mathematical model for prediction of the lathe tool life in the production environment taking into account feed, cutting speed and flank wear width. The series of experiments verified proposed mathematical models whereby the value of deviation of the results are within the standard deviation

The influence of conditions of forming composite coating polymer-magnetic powder on physico-mechanical properties of telecommunication optical fibers

Fеrоmаgnеtskа kоmpоzitnа prеvlаkа nа оptičkоm vlаknu оmоgućаvа idеntifikаciјu i dеtеkciјu tеlеkоmunikаciоnih оptičkih vlаkаnа/kаblоvа nаkоn njihоvоg pоlаgаnjа, primеnоm stаndаrdnih mаgnеtskih mеtоdа. U оvоm rаdu su dоbiјаnа оptičkа vlаknа sа kоmpоzitnоm fеrоmаgnеtskоm prеvlаkоm. Dеfinisаn је i оptimizоvаn prоcеsа njihоvоg dоbiјаnjа i vršеnа njеgоvа numеričkа simulаciја. Kоmpоzitnа prеvlаkа fоrmirаnа је prеvlаčеnjеm оptičkih vlаkаnа dispеrziјоm prаhоvа Bа-fеritа i SmCo5 u rаstvоru ЕVA u tоluеnu. Rаvnоmеrnоst dеblјinе kоmpоzitnе prеvlаkе ispitivаnа је kоrišćеnjеm mikrоskоpа sа оdbiјеnоm svеtlоšću. Аnаlizа mikrоskоpskih slikа bilа је оmоgućеnа kоrišćеnjеm sistеmа: mikrоskоp- digitаlnа kаmеrа- pеrsоnаlni rаčunаr sа оdgоvаrајućim prоgrаmоm zа kvаntifikаciјu vizuеlnih infоrmаciја. Rеzultаti dоbiјеni аnаlizоm slikе оbrаđеni su mаtеmаtičkо-stаtističkоm mеtоdоm. Ispitаn је uticај brzinе prеvlаčеnjа, kоncеntrаciје pоlimеrа i mаgnеtnоg prаhа u dispеrziјi nа rаvnоmеrnоst dеblјinе kоmpоzitnе prеvlаkе pоlimеr mаgnеtni prаh. Kао kritеriјum zа dеfinisаnjе unifоrmnе dеblјinе kоmpоzitnе prеvlаkе usvојеnа је nајmаnjа vrеdnоst stаndаrdnе dеviјаciје nајvеrоvаtniје vrеdnоsti prеčnikа оptičkоg vlаknа sа kоmpоzitnоm prеvlаkоm. Nа оsnоvu еkspеrimеntаlnih rеzultаtа, utvrđеnо је dа sе uticај svih istrаživаnih prоcеsnih pаrаmеtаrа nа rаvnоmеrnоst prеvlаkе, mоžе svеsti nа uticај viskоznоsti dispеrziје kојоm sе vrši prеvlаčеnjе. Ustаnоvlјеnа је оptimаlnа vrеdnоst viskоznоsti dispеrziје оd 1,20-1,24 Pas, zа ispitаni sistеm, kоја оmоgućаvа fоrmirаnjе kоmpоzitnе prеvlаkе nајrаvnоmеrniје dеblјinе. Pоtvrđеnо је dа svе prоcеsnе pаrаmеtrе: kоncеntrаciјu pоlimеrа i mаgnеtnоg prаhа, brzinu i tеmpеrаturu prеvlаčеnjа trеbа usklаditi tаkо dа sе prеvlаčеnjе оdviја dispеrziјоm čiја је viskоznоst оptimаlnа. Nа оsnоvu еkspеrimеntаlnо utvrđеnih rеоlоških јеdnаčinа zа pоnаšаnjе dispеrznоg sistеmа (prаhоvi Bа-fеritа ili SmCo5 dispеrgоvаni u rаstvоru ЕVА u tоluеnu) i pоstојеćеg mаtеmаtičkоg mоdеlа zа prеvlаčеnjе оptičkih vlаkаnа pоlimеrnоm prеvlаkоm rаzviјеn је mаtеmаtički mоdеl fоrmirаnjа kоmpоzitnе prеvlаkе nа оptičkоm vlаknu kојi је оmоgućiо numеričku simulаciјu prоcеsа prеvlаčеnjа оptičkih vlаkаnа kоmpоzitnоm prеvlаkоm. Numеričkоm simulаciјоm оmоgućеnо је ispitivаnjе uticаја vеćеg brоја prоcеsnih pаrаmеtаrа i оnih kојi nisu bili еkspеrimеntаlnо ispitivаni. Utvrđеnо је dа dеblјinа prеvlаkе nајvišе zаvisi оd gеоmеtriјskih kаrаktеristikа sistеmа zа prеvlаčеnjе. Vаlidnоst mоdеlа pоtvrđеnа је dоbrim slаgаnjеm rеzultаtа numеričkе simulаciје sа еkspеrimеntаlnim. Dоbiјеnа оptičkа vlаkаnа sа kоmpоzitnоm prеvlаkоm zаdržаvајu trаnsmisiоnа i pоbоlјšаvајu mеhаničkа svојstvа. Pri dејstvu spоlјаšnjеg јеdnоsmеrnоg i nаizmеničnоg mаgnеtnоg pоlја nа оptičkо vlаknо sа fеrоmеgnеtskоm kоmpоzitnоm prеvlаkоm nе dоlаzi dо prоmеnе u snаzi prеnеsеnе svеtlоsti. Ispitаnа оptičkа vlаknа mоgućе је kоristiti kао tеlеkоmunikаciоnа оptičkа vlаknа kоја sе mоgu lоcirаti kоrišćеnjеm mаgnеtnih mеtоdа.The ferromagnetic composite coating on optical fiber enables identification and detection of telecommunication optical fibers/cables after they have been laid down, using standard magnetic methods. In this thesis the optical fibers with composite ferromagnetic coating were obtained. The process of their synthesis was defined and optimized and numerical simulation of this process was performed. The composite coating was formed by coating optical fibers with dispersion of Ba-ferrite and SmCo5 powders in EVA solution in toluene. The coating thickness uniformity was investigated using optical microscope with reflective light. The analysis of microscope images was performed using the system: microscope - digital camera- personal computer with appropriate software for quantification of visual information. These results were evaluated using mathematical-statistic methods. The influence of coating rate, concentration of polymer and magnetic powder in dispersion on polymer-magnetic powder composite coating thickness was investigated. As criteria for defining uniform thickness of composite coating the minimal value of standard deviation of mean value of diameter of optical fiber with composite coating was established. According to experimental results it was found out that the influence of all investigated process parameters on coating uniformity ends up as the influence of viscosity of coating dispersion. For investigated system, the optimal value of viscosity of dispersion that enables forming the composite coating of the most uniform thickness was established as 1.20-1.24 Pa s. It was confirmed that all process parameters: concentration of polymer and magnetic powder and coating rate and temperature should be established in that manner that coating is performed with the evaluated optimal viscosity of dispersion. According to the experimentally estimated rheological equation for behavior of dispersed system (powders of Ba-ferrite and SmCo5 dispersed in EVA solution in toluene) and existing mathematical model for coating optical fibers with polymer coating the mathematical model of forming composite coating on optical fiber was established and enabled the numerical simulation of process of coating optical fibers with composite coating. By using numerical simulation it was possible to investigate higher number of process parameters and those that were not experimentally investigated. It was established that the coating thickness mostly depends on geometrical properties of the coating system. Validity of model was confirmed by good agreement of results obtained with numerical simulation with experimental. The obtained optical fibers with composite coating keep their transmission properties and improve mechanical. No change in the power of the propagated laser beam through the fiber optic with composite ferromagnetic coating was observed when external DC and AC magnetic fields were applied. It is possible to use the developed optical fibers as telecommunication optical fibers detectable by magnetic methods

Valuation of deferred taxes and its impact on companies' performance

Odlaganje poreskih plaćanja jedna je od najatraktivnijih kompanijskih strategija na polju upravljanja poreskim opterećenjem, ali iznosi odloženih poreza (kao i odloženih poreskih ušteda) dugo nisu mogli da se sagledaju iz finansijskih izveštaja. Dilema oko toga da li uopšte treba izveštavati o odloženim porezima i u kojoj meri njihovo iskazivanje omogućava realniju procenu performansi poslovanja još uvek je aktuelna. Cilj ove disertacije je da jednim celovitim istraživanjem fenomena odloženih poreza doprinese razrešenju postavljenih dilema...Tax deferral is one of the most attractive tax management strategie, but amounts of deferred taxes (as well as deferred tax savings) could not be perceived from the financial statements for a long period of time. Weather or not deferred taxes should be reported and to what extant they provide better evaluation of firm’s performance is still a question. The purpose of this dissertation is to contribute to answer of this question by providing a comprehensive research of the deffered taxes phenomenon. Deferred taxes result from temporary differences between financial accounting and tax rules of the calculation of periodic results. In order to assess justification for these differences and perspectives of deferred tax, a comparison between objectives and basic concepts of financial versus tax reporting was made, as well as the comparative analysis of the status and tendencies across certain countries with the emphasis on demonstrated advantages and disadvantages of different relationships between one and the other reporting system. It was shown that the compliance of income calculation for accounting and tax purposes would be at the expense of the achievement of objectives for both financial reporting and income taxation, so that the divergence is conceptually founded and desirable. However, this does not mean that ,in the same time, there does exist a possibility of using identical approaches on many issues. The divergence raises reporting costs and it is justified only if it contributes to the increase of expressive power of presented reports. Advantages of divergence over uniform model back up expectations that the differences between accounting and tax rules will keep on occurring, as well as deferred tax. The deffered taxes amount increases with the increase of the temporary differences and tax rates which applied to the temporary differences and give the amounts of of future increase and decrease of tax payments

A Catalog of Absorption Lines in Eight HST/STIS E230M 1.0 < z < 1.7 Quasar Spectra

We have produced a catalog of line identifications and equivalent width measurements for all absorption features in eight ultraviolet echelle quasar spectra. These spectra were selected as having the highest signal-to-noise among the HST/STIS spectra obtained with the E230M grating. We identify 56 metal-line systems toward the eight quasars, and present plots of detected transitions, aligned in velocity-space. We found that about 1/4 - 1/3 of the features in the Lya forest region, redward of the incidence of the Lyb forest, are metal lines. High ionization transitions are common. We see both O VI and C IV in 88 - 90% of the metal-line systems for which the spectra cover the expected wavelength. Si III is seen in 58%, while low ionization absorption in C II, Si II, and/or Al II is detected in 50% of the systems for which they are covered. This catalog will facilitate future studies of the Lya forest and of metal-line systems of various types.Comment: 13 pages, 2 figures, submitted to Monthly Notices of the Royal Astronomical Society, a complete version with the appendix and all figures is available at http://www.astro.psu.edu/users/misawa/pub/Paper/qalcat.pdf.g

Characterization of nanostructured spinel NiFe2O4 obtained by soft mechanochemical synthesis

Powdery nickel ferrite, NiFe2O4 has been obtained by soft mechanochemical synthesis in a planetary ball mill. Ni(OH)2 and Fe(OH)3 are used as initial compounds. This mixture was mechanically activated for 25h, uniaxial pressed and sintered at 1100°C for 2h. The phase composition of the sintered sample was analyzed by X-ray diffraction (XRD), energy dispersive spectrometer (EDS) and Raman spectroscopy. Morphologies were examined by scanning electron microscopy (SEM). The electrical DC/resistivity/conductivity at different temperatures was measured using a Source Meter Keithley 2410. An Impedance/Gain-Phase Analyzer (HP-4194) was used to measure the impedance spectra (100Hz - 10MHz) at different temperatures. [Projekat Ministarstva nauke Republike Srbije, br. III 45003 i br. III 45015

Supplementary data for the article: Stojsavljević, A.; Trifković, J.; Rasić-Milutinović, Z.; Jovanović, D.; Bogdanović, G.; Mutić, J.; Manojlović, D. Determination of Toxic and Essential Trace Elements in Serum of Healthy and Hypothyroid Respondents by ICP-MS: A Chemometric Approach for Discrimination of Hypothyroidism. Journal of Trace Elements in Medicine and Biology 2018, 48, 134–140. https://doi.org/10.1016/j.jtemb.2018.03.020

Supplementary material for: [https://doi.org/10.1016/j.jtemb.2018.03.020]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2181]Related to accepted version: [http://cherry.chem.bg.ac.rs/handle/123456789/3074

Inflammation, nutritional status, pufa profile and outcome in hemodialysis patients

Patients with end-stage renal disease (ESRD) include a significant percentage of malnourished patients with other risk factors: dyslipoproteinemia, insulin resistance, increased oxidative stress and inflammation that together impair endothelial function. Abnormal polyunsaturated fatty acids (PUFA) patterns are reported in patients with ESRD. The basic mechanisms of these disorders are connected with changes in cell functions at the membrane level. Vascular smooth muscle cell proliferation plays an important role in the pathogenesis of atherosclerosis. We have examined the association between atherosclerotic risk factors and nutritional status in hemodialysis (HD) patients. Mortality was followed for up to 18 month. Forty-three HD patients were examined (20 males, 23 females, ages 55±12 years). Nutritional and inflammatory markers, including serum concentrations of C-reactive protein (CRP), tumor necrosis factor alpha (TNF-alpha), and interleukin 6 (IL-6), were measured. There was significant positive correlation between the plasma albumin level and CRP. Significant correlation was found between plasma the cholesterol level and some PUFA. Increasing inflammation and endothelial dysfunction predict the development of vascular disease. We report on the relationship between inflammatory markers and nutritional parameter, indices of atherosclerosis and other cardiovascular risk factors in patients on hemodialysis

Supplementary data for the article: Ilić, I.; Milutinović-Nikolić, A.; Mojović, Z.; Vuković, Z.; Vulić, P.; Gržetić, I.; Banković, P.; Jović-Jovičić, N. Oxidative Degradation of Aromatic N-Compounds Using Cobalt Containing Montmorillonite-Based Catalysts. Applied Clay Science 2020, 193, 105668. https://doi.org/10.1016/j.clay.2020.105668

Supplementary material for: [https://doi.org/10.1016/j.clay.2020.105668]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/4045