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Završni rad počinje s opisom električnih motora te navodi detaljnu listu nekih izvedbi reluktantnih motora. Zatim imamo listu potrebnih magnetskih i električnih veličina, koje su detaljno objašnjene. Nakon toga dolaze formule koje su potrebne za analitički postupak računanja sile u magnetskom krugu. Opisan je solenoid i odrađena je simulacija u programu Ansys Maxwell. Opisan je sam program Ansys, a rezutati simulacije su prikazani grafički i računski. The final paper begins with a description of electric motors and provides a detailed list of some designs of reluctance motors. Then we have a list of required magnetic and electrical quantities, which are explained in detail. After that come the formulas that are necessary for the analytical procedure of calculating the force in the magnetic circuit. The solenoid was described and the simulation was performed in the Ansys Maxwell program. The Ansys program itself is described, and the simulation results are presented graphically and computationally.

Jednofazni izravni izmjenični pretvarači napona spadaju u najjednostavnije pretvaračke sklopove koji omogućuju upravljanje efektivnom vrijednošću struje trošila promjenom kuta okidanja. U ovom radu, prikazana je analiza rada izmjeničnog pretvarača napona opterećenog radnim i induktivnim trošilom. Također, provedena su mjerenja na izmjeničnom pretvaraču u slučaju radnog i induktivnog opterećenja s ciljem promjene induktivnosti prigušnice. Koncept elektronički upravljane prigušnice podrazumijeva upravljanje induktivnošću prigušnice promjenom kuta okidanja. Snimljeni su valni oblici napona i struje trošila koji su kasnije uspoređeni s valnim oblicima dobivenim u provedenoj analizi rada. Sva mjerenja obavljena su uz pomoć didaktičko multimedijalne opreme Lucas-Nülle i programa LabSoft. Single-phase direct AC voltage converters are among the simplest converters that enable the control of the RMS value of the consumer current by changing the trigger angle. In this paper, an analysis of the operation of an alternating voltage converter loaded with a working and inductive consumer is presented. Also, measurements were performed on the AC converter in case of operating and inductive load with the aim of changing the inductance of the electric coil. The concept of electronically controlled inductance involves controlling the inductance by changing the trigger angle. Voltage and current waveforms were recorded, which were later compared with the waveforms obtained in the performed analysis. All measurements were performed with the help of the Lucas-Nülle didactic multimedia equipment and the LabSoft program.

Zadatak završnog rada je izrada kontrolera električnih roleta prozora korištenjem Arduino mikrokontrolera. Temeljni cilj izrade ovog rada bila je pristupačnije, jednostavnije i sigurnije rješenje kontrole prozorskih roleta. Rad se bazira na Arduino Nano mikrokontroleru. Od ostalih komponenata korišteni su elektromagnetski releji, solid state releji, infracrveni prijemnik, daljinski upravljač i senzor kiše. Radu je priložen Arduino program s kojim mikrokontroler obavlja navedeni zadatak. Rad prikazuje kako pojava elektromagnetske interferencije može utjecati na stabilnost elektronike. Testiranjem sklopa prikazane su prednosti i nedostatci korištenja Arduino mikrokontrolera u odnosu na standardno korištenje PLC-ova te nekoliko načina unaprjeđenja.

Osnovno obilježje suvremenog poslovanja i međunarodne ekonomije je intenzivna tehnološka podrška i ovisnost o tehnološkim inovacijama. Rezultat toga je stvaranje digitalnih poduzeća i digitaliziranog globalnog društva. Proces koji dovodi do toga naziva se digitalna transofmacija, a označava napuštanje nekadašnjeg tradicionalnog poslovanja, te uvođenje računalnih, infomacijsko-komunikacijskih i digitalnih rješenja u sve poslovne procese. Digitalizacija međunarodne ekonomije vrlo je dinamična i turbulentna. O razini njezina razvoja, posebice u razvijenijim državama svijeta, najbolje svjedoče konkretni primjeri. Neki od njih su Booking, Amazon, Facebook i slični. Ovu praksu poslovanja sve uspješnije slijedi i Hrvatska, a ogledni primjeri digitalnih poduzeća i onih koja se razvijaju u tom smjeru su Njuškalo, Maistra, Podravka, Agrokor i slični. Digitalno poslovanje općenito donosi niz pozitivnih učinaka. Osim efikasnosti i učinkovitosti poslovanja, misli se na maksimiziranje kvalitete i reduciranje pogrešaka, automatizaciju, proširenje poslovanja, uspješnije konkuriranje i slično. Uslijed navedenoga, smatra se kako će se proces nastaviti i u budućnosti te utjecati na razvoj digitalne ekonomije. One of the main features of the modern business and the international economy is it is the intensity of high technological support and dependence on technological innovation. The results of those trades are digital businesses and digitized global society. The process that leads to this is digital transformation, which includes marking the abandonment of former traditional jobs, introducing computer, information-communication and digital solutions into all business processes. The digitalization of the international economy is very dynamic and turbulent. To confirm that it is important to mention some of the concrete examples. Some of them are Booking, Amazon, Facebook and similar. Croatia successful follows world practice and contemporary trends. The examples of digital companies and those that are developing in this way are Njuškalo, Maistra, Podravka, Agrokor and the like. Digital business generally has numerous positive effects. Apart from efficiency and sparse business, it is important to mention the maximizing quality and reducing errors, automatization, expanding the business, using competition and the like. In the future we can this process will continue and will leat to the digital international economy.

In this Ph.D. thesis, a new methodology for Reactor Synthesis Based on Process Intensification Concepts and Application of Optimization Methods (ReSyPIO) is presented and applied to two different cases. In Chapter 1: Introduction – Motivation and Objectives, the motive for the research is presented, and Hypotheses are formulated. The ReSyPIO methodology that rests upon these Hypotheses and consists of three consecutive stages is briefly described in this Chapter. The first stage encapsulates all present phases and phenomena inside the reactor functional building block, called module. Modules come as a direct result of a conceptual representation of the analyzed system. In the second stage, modules are further segmented if needed and interconnected, creating a reactor superstructure that is mathematically described for all desirable operating regimes. In the last stage of the ReSyPIO methodology, the optimal structure, operating conditions, and the operational regime are determined with the use of rigorous optimization. All three stages of the ReSyPIO methodology have a backflow, meaning that if analysis leads to impractical, nonfunctional or inefficient results, modifications in reactor superstructure and modules can be made. The objective is to conceptually and numerically derive the most efficient reactor structure and a set of operating conditions that would be used as a starting point in the future reactor design. Chapter 2: Literature Review is used to cover and review the most important research published in the area of Process Intensification and different Process System Engineering techniques. Different approaches and studies present in academia are highlighted and their elements compared with the presented ReSyPIO methodology with the accent on its advantages and contribution to the engineering science community.Also, in this Chapter, an array of well researched analytical and numerical approaches is presented that could be used in the future to strengthen the ReSyPIO methodology further and facilitate its easier application. In Chapter 3: Description of the ReSyPIO Methodology Reactor Synthesis based on Process Intensification and Optimization of Superstructure is explained in detail, with a graphical representation of the main building block, called Phenomenological Module. A general explanation is given on how to form a reactor superstructure and mathematically describe it with sets of material and energy balance equations that correspond to a number of present phases and components in the system. The ReSyPIO methodology is first applied to a generic case of two parallel reactions in Chapter 4, called Application of the ReSyPIO Methodology on a Generic Reaction Case. The case corresponds to two parallel reactions that could be found in the fine chemical industry. The reactions are endothermic and slow with the undesired product. After the application of the ReSyPIO methodology, an optimal reactor structure consisting of a segmented module with 17 side inlets for the reactant and heat source is obtained. It is recommended for the reactor to work in a continuous steady-state mode as the dynamic operation would not lead to a sufficient increase in reactor efficiency... U ovoj doktorskoj disertaciji je predstavljena i primenjena nova metodologija za sintezu reaktora zasnovana na konceptima intenzifikacije procesa i primeni različitih optimizacionih tehnika (Reactor Synthesis Based on Process Intensification Concepts and Application of Optimization Methods – ReSyPIO). U poglavlju Uvod – Motivacija i ciljevi, formirane su hipoteze na kojima počiva ReSyPIO metodologija i data je motivacija za istraživanje. ReSyPIO metodologija je ukratko predstavljena i opisana kroz tri uzastopne etape. Prva etapa uokvirava sve prisutne faze i fenomene u reaktoru unutar funkcionalnih gradivnih jedinica, nazvanih moduli. Moduli predstavljaju rezultat konceptualnog prikaza analiziranog sistema. U drugoj etapi, moduli se po potrebi mogu dalje podeliti u segmente i međusobno povezati, kreirajući superstrukturu reaktora. Superstruktura je matematički opisana za sve režime rada reaktora od interesa. U poslednjoj etapi ReSyPIO metodologije, optimalna struktura, uslovi i režim rada reaktora su određeni primenom rigorozne optimizacije. Sve tri etape ReSyPIO metodologije imaju povratni tok, što znači da ukoliko analiza vodi ka nepraktičnim, nefunkcionalnim ili neefikasnim rešenjima, modifikacija matematičkog modela, superstrukture i/ili modula je moguća. Cilj primene ReSyPIO metodologije je da se konceptualnim i numeričkim pristupom dođe do optimalne preporuke za strukturu reaktora, operativne uslove i režim rada, koja bi bila početna pretpostavka u budućem dizajnu uređaja. Pregled literature daje opis i prikaz svih istraživanja od interesa, iz oblasti Intenzifikacije procesa i Teorije i analize procesnih sistema. Naglašeni su različiti pristupi i studije prisutne u istraživačkojzajednici, a njihovi elementi upoređeni sa predstavljenom ReSyPIO metodologijom sa akcentom na prednostima i naučnom doprinosu. U ovom poglavlju je dat i niz dobro istraženih analitičkih i numeričkih pristupa koji bi mogli da budu korišćeni u okviru ReSyPIO metodologije i olakšaju njenu primenu. U poglavlju Opis ReSyPIO metodologije, je detaljno objašnjena sinteza reaktora zasnovana na konceptima intenzifikacije procesa i optimizaciji superstrukture. Prvo je data procedura za grafičku i konceptualnu reprezentaciju sistema, preko glavnih gradivnih jedinica, fenomenoloških modula. Potom je objašnjeno kako se kreira superstruktura reaktora. Na kraju je dat uopšten postupak za matematički opis superstrukture preko skupova jednačina materijalnog i energetskog bilansa, čiji broj zavisi od broja prisutnih faza i komponenata u sistemu. ReSyPIO metodologija je prvi put primenjena na slučaju dve generičke paralelne reakcije u poglavlju pod nazivom Primena ReSyPIO metodologije na slučaju generičke reakcije. Ovaj slučaj odgovara reakcijama koje se mogu naći u industriji finih hemikalija. Reakcije su endotermne i spore, pri čemu je kinetički favorizovano kreiranje neželjenog proizvoda. Nakon primene ReSyPIO metodologije, dobijena je optimalna struktura reaktora koja se sastoji od segmentisanog modula sa 17 ulaza za izvor toplote i reaktant koji se dozira. Predloženo je da reaktor radi kontinualno, u stacionarnom režimu rada, jer bi dinamički režim rada rezultovao nedovoljnim povećanjem efikasnosti reaktora...

Vodeni balast koji se koristi na brodovima radi osiguranja stabilnosti oslanja se na usisavanju mora u predviđene tankove. Za razliku od prošlih vremena, studije su pokazale kako preseljenje tisuća kubika mora iz jedne u neku drugu točku na našoj planeti, zapravo stvara invazije alohtonih vrsta u novim područjima. Ta prirodna pojava može imati veliki utjecaj na ravnotežu različitosti nekog morskog ekosustava, a posljedice se onda odražavaju na ljudsko zdravlje, na gospodarstvo i čovjekove aktivnosti te na ekološki integritet tog mjesta. Ekološke promjene se mogu lakše razumjeti i predvidjeti ako se poznaju karakteristike svakog pojedinog organizma te se onda mogu i razviti sustavi koji, obradom te vode, sprječavaju unos štetnih organizama u nova mora.

BACKGROUND: Oscillatory baffled reactors have good prospect for use in batch to continuous transition for many industries. For reliable design and scale up it is essential to mathematically describe mixing and flow pattern of oscillatory flow. The aim of this study is to investigate the effects of operating conditions on residence time distribution (RTD) of liquid phase in a continuous oscillatory baffled reactor (COBR) and to propose a correlation that accurately describes the flow pattern. RESULTS: Analysis of results obtained for a wide variety of operating conditions in two geometrically similar reactors show that increase of oscillation frequency and amplitude both decrease axial dispersion, with a more prominent effect of amplitude. Proposed power-law correlation is in very good agreement with all performed experiments. Peclet numbers predicted by this correlation are in reasonably good agreement with the literature experimental data and is much better than the ones obtained by the commonly used correlation, which contains more fitting parameters. CONCLUSION: Results show that relatively high amplitudes, low frequencies and low to moderate secondary non-oscillatory flow should be used to ensure effective mixing with a low net flow in COBR. Developed correlation offers a simple, yet reliable way to predict the macroscopic flow pattern of liquid in COBR.

In general, electrochemical (EC) systems are non-linear, which means they respond nonlinearly to a frequency-dependent periodic input perturbation of high amplitude imposed around a steady-state. In addition, the kinetics of EC reactions are quite complex and different rivalling model presentations can be formulated for certain EC reaction. While standard electrochemical methods (steady-state and electrochemical impedance spectroscopy) showed low sensitivity towards the model discrimination, non-linear frequency response analysis (NLFRA) of EC kinetics can appear advantageous for this purpose. In this work, NLFRA is applied in experimental and theoretical study of ferrocyanide oxidation as a model EC reaction. Belgrade, Serbia, June 6-10, 2010 Related to the published paper in the Proceedings of the Second Regional Symposium on Electrochemistry South-East Europe, [http://cer.ihtm.bg.ac.rs/handle/123456789/3539]