Functional and Environmental Advantage of Cleaning Ti5B1 Master Alloy

One of the greatest environmental goals for the aluminum alloys industry is generating higher quality products by introducing cleaner input materials while maintaining low production costs. A typical dilemma for the master alloy producers is the cleanness level of the master alloy since insoluble inclusions could serve as inoculants during the solidification process. In this work, commercial Ti5B1 master alloy is used for grain refinement of Al7Si4Cu aluminum alloy and compared with the cleaned master alloy that contained a lower amount of residual refractory oxides and salts. Metallography analysis was used for grain size measurement while Computer Aided Cooling Curve Analysis was used for assessment of the undercooling and heat release values. In all instances, specimens treated with the cleaned master alloy showed smaller grains in the final structure and lower undercooling values. The difference in released heat between liquidus and recalescence temperatures was about 25% in specimens where added 0.66 wt% of cleaned master alloys compared to specimens where the commercial master alloys were added. Using cleaner Ti5B1 master alloy with a higher number of TiAl3 and TiB2 particles improves its grain refinement efficiency and transmits fewer impurities in produced parts. Producing cleaner master alloy would be beneficial from economic and environmental aspects by increasing its value and service time of produced parts besides simplifying the recycling process at the end of parts life-cycle.This is the peer reviewed version of the paper: Mitrašinović, A., Tomić, M., 2021. Functional and Environmental Advantage of Cleaning Ti5B1 Master Alloy, International Journal of Precision Engineering and Manufacturing-Green Technology, [https://doi.org/10.1007/s40684-021-00339-2

Improving the model of organization and management of business processesin industrial service companies

U doktorskoj disertaciji su predstavljeni modeli za unapređenje organizacione strukture i upravljanja poslovnim procesima i upravljanje performansom poslovnih procesa. U prvom modelu su razvijeni postupci analize, modelovanja, ocenjivanja i vrednovanja postupaka unapređenja struktura i poslovnih procesa, a u drugom modelu su postavljene faze planiranja, merenja i vizuelizacije performansi poslovnih procesa. Primenjeni su savremeni softveri za upravljanje procesima i njihovim performansama. Mogućnost praktične primene razvijenih modela istražena je u dve studije slučaja realnog idustrijskog uslužnog preduzeća.In his doctoral dissertation, presented models for improving organizational structures and business process management and performance management business processes. In the first model developed methods of analysis, modeling, assessment and evaluation procedures to improve the structure and business processes, and in the second model are set phases of planning, performance measurement and visualization of business processes. Were applied modern software management processes and their performance. A possible application of the developed model was investigated in two case studies of real industrial service enterprise

Improving the model of organization and management of business processesin industrial service companies

U doktorskoj disertaciji su predstavljeni modeli za unapređenje organizacione strukture i upravljanja poslovnim procesima i upravljanje performansom poslovnih procesa. U prvom modelu su razvijeni postupci analize, modelovanja, ocenjivanja i vrednovanja postupaka unapređenja struktura i poslovnih procesa, a u drugom modelu su postavljene faze planiranja, merenja i vizuelizacije performansi poslovnih procesa. Primenjeni su savremeni softveri za upravljanje procesima i njihovim performansama. Mogućnost praktične primene razvijenih modela istražena je u dve studije slučaja realnog idustrijskog uslužnog preduzeća.In his doctoral dissertation, presented models for improving organizational structures and business process management and performance management business processes. In the first model developed methods of analysis, modeling, assessment and evaluation procedures to improve the structure and business processes, and in the second model are set phases of planning, performance measurement and visualization of business processes. Were applied modern software management processes and their performance. A possible application of the developed model was investigated in two case studies of real industrial service enterprise

Optofluidic Micromachined Platform for Refractive Index Measurement

We present a combination of micromachined optofluidic platforms equipped with a fiber-optic sensing configuration based on a three-path Mach–Zehnder interferometer (MZI) for simultaneous measurement of the refractive index of liquids and the autocalibration in dynamic regime. The sensing principle is based on the low-coherence interferometry, characterized by a generation of Gaussian enveloped interferograms, for which the position of its maximum depends on the optical path difference (OPD) between the sensing and reference arm of the MZI. When liquid flows through the central microchannel of the optofluidic platform it crosses the light beam between the two optical fibers in the sensing arm causing the OPD change. An algorithm has been applied for the calculation of the refractive index of liquids out of the raw interference signals. We obtained a very good agreement between the experimental results and literature data of refractive indices of subjected fluids. The accuracy of refractive index measurement is approximately 1%, predominantly determined by the accuracy of reading the position of the mechanical scanner. The proposed sensor is attractive for the label-free biological, biochemical, and chemical sensing owing autocalibration and high sensitivity yet consuming a very small sample volume of 1 µL. It is capable to measure the refractive index of various liquids and/or gases simultaneously in the process

The effect of chemical modification of clays on the structure and properties of its epoxy nanocomposites

Epoksidni nanokompoziti (NK) na bazi diglicidil-etra bisfenola A (DGEBA) pretpolimera i višefunkcionalnog poli(amidoamina) (PAA) kao umreživača su pripremljeni in situ polimerizacijom u prisustvu komercijalnih hemijski modifikovanih montmorijonita (Cloisite®30B; Cloisite®15A) i onih sintetisanih reakcijom jonske izmene sa protonovanim heksadecilaminom (HDA-Mt) i umreživačem (PA-Mt). Pri pripremi NK, 0,5–10 mas.% montmorijonita (Mt) je direktno umešavano sa rastvorom DGEBA, odnosno prethodno dispergovano u pogodnom sistemu rastvarača...Epoxy nanocomposites (CPN) based on diglycidyl ether of bisphenol A (DGEBA) prepolymer and multifunctional poly(amidoamine) (PAA) curing agent were prepared by in situ polymerization in the presence of commercial chemically modified montmorillonites (Cloisite®30B; Cloisite®15A), as well as ones synthesized by ion exchange reaction with protonated hexadecylamine (HDA-Mt) and PAA (PA-Mt). The 0.5–10 wt.% of montmorillonite (Mt) was directly mixed with DGEBA solution or previously dispersed in a suitable solvent system..

Угрожавање националне безбедности сецесијом територија са расположивим природним ресурсима: случај Србије, Украјине и Шпаније

Процес сецесије у теоријском и практичном смислу тумачи се као оспоравање легитимитета и суверене надлежности над једним делом територије коју насељава етничка група по бројности мањинска у односу на остатак становништва, од до тада јединствене државе ради покушаја успостављања „нове― творевине са елементима државности. Читав процес сецесије прати низ негативних безбедносних последица различитих по интензитету и потенцијалу угрожавања постојеће националне државе (држава домаћин). Првенствено нарушавање територијалне целовитости националних држава неизоставно прати и низ других економских и друштвених деформација чији крајњи ефекти доприносе нестабилном безбедносном стању. С обзиром да је пројектовани циљ ове дисертације дескриптивна анализа утицаја сецесије територија са расположивим природним ресурсима на националну безбедност, рад је структурисан тако да се обухвате основне вредности (политичке, економске, еколошке и социјалне) за које постоји могућност угрожавања. У првом делу рада представљена су основна теоријска уопштавања сецесије као политичког феномена и права на самоопредељење народа у контексту не/оправданости унилатералне сецесије. Затим блиско повезана политичка економија сецесије (у чијем се средишту налазе расположиви природни ресурси) обухвата најважније теоријске ставове поткрепљене емпиријским резултатима о повезаности сецесије и потенцијалног незадовољства једног дела становништва у погледу сувереног права располагања природним ресурсима. Последња анализирана димензија сецесије садржи теоријска упоштавања социолошких научних праваца које описују повезаност сецесије, природних ресурса и насилних сукоба представника институција националне државе с једне и сецесионистичких покрета с друге стране што између осталог потврђују резултати ове докторске дисертације. Примењена истраживачка стратегија односи се на компаративно проучавање три случаја (покушаја) сецесије Косова и Метохије, Доњецка, Луганска и Каталоније као делова националних територија суверених држава (Србије, Украјине и Шпаније) у оквиру којих је потврђено веће присуство природних ресурса и последично наглашене сецесионистичке тежње. Остварени резултати ове докторске дисертације упућују на закључак да је сецесија територија са расположивим природним ресурсима безбедносна претња која поседује висок потенцијал угрожавања националне безбедности Србије, Украјине и Шпаније. Компарацијом сецесионистичких покрета и успешности остваривања њиховог циља, уочава се суштинска разлика у погледу капацитета националних институција надлежних за решавање унутар државних проблема као и става водећих актера међународне политике о поштовању територијалне целовитости или насупрот томе залагању за остваривање права на политичко самоопредељење.The process of secession in theoretical and practical terms is interpreted as challenging the legitimacy and sovereignty over one part of the territory inhabited by an ethnic group minority in relation to the rest of the population, from a single state to try to establish a "new" creation with elements of statehood. The whole process of secession is accompanied by negative security consequences, different in intensity and potential of endangering the existing nation state (host state). Primary violation of the territorial integrity of nation-states inevitably accompanies other economic and social deformations, the final effects of which contribute to the unstable security situation. Since the projected goal of this dissertation is a descriptive analysis of the impact of secession of territories with available natural resources on national security, the paper is structured to include basic values (political, economic, environmental and social) for which there is a possibility of endangerment. The first part of the paper presents the basic theoretical generalizations of secession as a political phenomenon and the right to self-determination of the people in the context of non / justification of unilateral secession. Then the closely related political economy of secession (at the center of which are available natural resources) includes the most important theoretical views supported by empirical results on the connection between secession and potential dissatisfaction of one part of the population regarding the sovereign right to dispose of natural resources. The last analyzed dimension of secession contains theoretical considerations of sociological scientific directions that describe the connection between secession, natural resources and violent conflicts between representatives of nation state institutions on the one hand and secessionist movements on the other, which is confirmed by the results of this doctoral dissertation. The applied research strategy refers to the comparative study of three cases (attempts) of secession of Kosovo and Metohija, Donetsk, Lugansk and Catalonia as parts of the national territories of sovereign states (Serbia, Ukraine and Spain) within which the greater presence of natural resources was confirmed. The achieved results of this doctoral dissertation point to the conclusion that the secession of territories with available natural resources is a security threat that has a high potential of endangering the national security of Serbia, Ukraine and Spain. The comparison of secessionist movements and the success of their goal shows a significant difference in the capacity of national institutions responsible for solving state problems as well as the attitude of leading actors in international politics on respect for territorial integrity or opposition to the right to political self-determination

A Stochastic Theory of Wavelets

The term wavelet implies a function generating base for decomposition of the finite energy signals both in spatial and in frequency domain concurrently. Construction of wavelets that have compact support and arbitrary high regularity was ultimately done by Ingrid Daubechies in 1988. Detailed subspaces of the multiresolution analyses are regarded to be the age eigenstates wandering in terms of the evolution. Future expansion of this topic would be useful

Fiber-optic Mach-Zehnder Interferometer for Refractive Index Measurement Based on MEMS Optofluidic Platform

We present a fiber-optic sensing configuration based on Mach-Zehnder interferometer (MZI) embedded into the MEMS optofluidic platform for measurement of index of refraction of liquids in dynamic regime. The sensing principle is based on the low-coherence interferometry, characterized by generation of Gaussian shape interferograms, which maximum position depends on the optical path difference (OPD) between the sensing and reference arm of the MZI. When liquid flows through the central microchannel of the optofluidic platform it crosses the light beam between the two optical fibers in the sensing arm causing the OPD change. An algorithm has been applied for calculation of index of refraction of liquids out of the raw interference signals. We obtained very good agreement between the experimental results and literature data of index of refraction of subjected fluids. The accuracy of index of refraction measurement is about 1 % that is predominantly determined by accuracy of reading the position of mechanical scanner

Position Measurement over Wide Range by Simultaneous Use of Low and High Coherence Light Source

In this paper we propose and experimentally demonstrate a new technique for position/displacement measurement using fiber optic interferometry. We simultaneously employ a low- and a high- coherence light source in the same opto-mechanical configuration. The low coherence signal was obtained using a Fizeau receiving interferometer, implemented as an optical glass wedge, accompanied by a linear CCD array. Combining low- and high-coherence parts was possible because we showed that the accuracy of low-coherence based position measurement was better than 50 nm, less than the high coherence signal periodicity. We verify the method in the dynamic range of low-coherence measurement of about 100 um, while the accuracy of the high-coherence part was about ±1 nm. Thus, the method provides more than 100,000 measuring points. The advantages of this sensing technique include absolute position/displacement measurement in a large dynamic range with nanometer accuracy