Croatian Digital Thesis Repository
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Design of two-pole high-voltage connector
No full textOvaj rad se bavi konstruiranjem dvopolne pravokutne visoko naponske spojnice. Spojnice su bitne komponente u automobilskoj industriji pogotovo u današnje vrijeme s rastom električnih automobila. Jedna od bitnih komponenti koje će imati ova spojnica je zupčanik i zubna letva koje služe za smanjenje sile ukapčanja, te će biti dodatno razrađene u ovom radu. Rad se sastoji od opisa visoko naponskih spojnica, provjerom patenata te izradom koncepata. Koncepti se ocjenjuju i uspoređuju, najbolji koncept se dalje detaljnije razrađuje. Detaljna konstrukcijska razrada koncepta uključuje proračun zupčanika i zubnih letvi, te izrada 3D modela s odgovarajućom tehničkom dokumentacijom. 3D model spojnice se izrađuje u programskom paketu Solidworks, dok se proračun čvrstoće provodi analitički.This thesis deals with the construction of a two-pole rectangular high-voltage connector. Connectors are essential components in the automotive industry, especially nowadays with the growth of electric cars. One of the essential components that this connector will have is the gear and rack, which serve to reduce the clamping force, and will be further elaborated in this work.The work consists of a description of high-voltage connectors, checking patents and creating concepts. Concepts are evaluated and compared, the best concept is further developed in more detail. The detailed design development of the concept includes the calculation of gears and racks, and the creation of a 3D model with appropriate technical documentation. The 3D model of the connector is created in the Solidworks software package, while the strength calculation is performed analytically
The influence of the functional comonomer in the structure of the polymer additive on the low-temperature behavior of diesel and biodiesel fuel
No full textU ovome radu su sintetizirani i pročišćeni polimerni aditivi. Prilikom sinteze svih polimernih aditiva korišteni su monomeri metil metakrilat (MMA), dodecil metakrilat (DDMA) i oktadecil metakrilat (ODMA), te ovisno o odabranome polimernome sustavu, funkcionalni monomer tert-butilaminoetil metakrilat (TBAEMA), 2-(diizopropilamino)etil metakrilat (DIPOAEMA) ili 2-(dietilamino)etil metakrilat (DEAEMA). Struktura i čistoća polimernih aditiva potvrđena je korištenjem spektroskopskih metoda infracrvene spektroskopije s Fourierovom transformacijom i protonske nuklearne magnetske rezonancije. Polimeri su podvrgnuti diferencijalnoj pretraženoj kalorimetriji i kromatografiji isključenja, kako bi im se odredila toplinska svojstva i prosječna molekulska masa polimera. Za ispitivanje svojstava formulacija s dizelskim i biodizelskim gorivom, pripravljene su formulacije goriva s 2000 ppm polimernih aditiva. Formulacije su analizirane uz pomoć diferencijalne pretražne kalorimetrije i proučavana je promjena morfologije kristala optičkim mikroskopom s polarizacijom. Određene su točke filtrabilnosti i tecište prema standardnim metodama EN 116 za točku filtrabilnosti i ASTM D5950 za tecište. Dobiveni rezultati pokazali su sniženje temperature tecišta i filtrabilnosti dizelskom gorivu kod svih sintetiziranih polimernih aditiva, a najbolji rezultat pokazao je sustav MDO30-1:1-DEA10 koji je snizio vrijednost točke filtrabilnosti dizelskoga goriva od -8 °C do -18 °C te vrijednost tecišta od -18 °C do -45 °C.In this paper, polymer additives were synthesized and purified. Monomers methyl methacrylate (MMA), dodecyl methacrylate (DDMA) and octadecyl methacrylate (ODMA) were used in the synthesis of all polymer additives, and depending on the selected polymer system, functional monomer tert-butylaminoethyl methacrylate (TBAEMA), 2-(diisopropylamino)ethyl methacrylate (DIPOAEMA) or 2-(diethylamino)ethyl methacrylate (DEAEMA). The structure and purity of polymer additives was confirmed using fourier transform infrared spectroscopy methods and proton nuclear magnetic resonance. Polymers underwent differential scanning calorimetry and exclusion chromatography, to determine their thermal properties and average molecular weight of polymers. For testing the properties of diesel and biodiesel fuel formulations, fuel formulations with 2000 ppm polymer additives were prepared. Formulations were analyzed with the help of differential scanning calorimetry and the change in crystal morphology by optical microscope with polarization was studied. The filtrability points and flow according to the standard methods are EN 116 for the cold filter plugging point and ASTM D5950 for the pour point. The obtained results showed a decrease in the temperature of the liquid and filtrability of diesel fuel in all synthesized polymer additives, and the best result was shown by the MDO30-1:1-DEA10 system, which lowered the value of the cold filter plugging point of diesel fuel from -8 °C to -18 °C and the pour point liquid from -18 °C to -45 °C
Construction of Parking Lot : Undergraduate Thesis
No full textU radu je obrađen hipotetski slučaj izgradnje parkirališta za kojeg je potrebno odrediti sve tehnološke procese, odabrati strojeve za svaku od aktivnosti u pojedinim procesima, te uskladiti njihov rad pri skidanju humusnog, širokom iskopu, zaštiti pokosa i izgradnji parkirališta s asfaltnom površinom. Cilj je postizanje što veće učinkovitosti poštujući sve norme i standarde pri gradnji.This paper discusses a hypothetical case of constructing a parking lot, for which it is necessary to determine all technological processes. Select machines for each of the activities within the individual processes and coordinate their work in removing topsoil, wide excavation, slope protection, and parking lot construction with asphalt surfacing. The goal is to achieve maximum efficiency while adhering to all construction norms and standards
Modeliranje kontinuirane farmaceutske sinteze u svrhu vođenja procesa
No full textThis work investigates the modelling and sensitivity analysis of the Simmons-Smith reaction, a critical process for the synthesis of cyclopropanes, in a plug flow reactor (PFR) for continuous pharmaceutical synthesis. Using dibromomethane and cyclohexene as substrate, the study replaces the conventional copper catalyst with grated zinc, which represents a simplified and potentially more sustainable approach. A dynamic model was developed to predict the reaction behaviour under different operating conditions, such as temperature and flow rate, allowing better control of the reaction dynamics. The analysis showed that higher temperatures and slower flow rates improve reactant conversion and product yield, while lower temperatures and higher flow rates reduce reaction efficiency. Sensitivity tests revealed a lag between the changes in the input variables and the observable effects, emphasising the importance of understanding transient dynamics. The models for two experimental setups showed agreement with the observed data, although some deviations highlighted the need for refinements, particularly in thermal and kinetic representations.
The results emphasise the potential of PFR systems for scalable, efficient and controlled organometallic reactions. This study advances the application of continuous flow systems in pharmaceutical production and promotes sustainable synthesis technologies.Ovaj diplomski rad istražuje modeliranje i analizu osjetljivosti Simmons-Smithove reakcije, važnog procesa za sintezu ciklopropana, unutar idealnog reaktora s čepolikim strujanjem za kontinuiranu farmaceutsku sintezu. Koristeći dibromometan i cikloheksen kao supstrat, u ovom radu se zamjenjuje bakar kao konvencionalni katalizator s cinkom nudeći pojednostavljeni i potencijalno održiviji pristup. Razvijen je dinamički model za predviđanje vladanja procesa reakcije pod različitim radnim uvjetima, kao što su temperatura i protok. Analiza je otkrila da više temperature i manji protoci povećavaju konverziju reaktanata i prinos proizvoda. Testiranje osjetljivosti utvrdilo je kašnjenje između promjena parametara i vidljivih učinaka, naglašavajući važnost razumijevanja dinamičkog vladanja procesa.
Modeli koji opisuju provedene eksperimente donekle prate eksperimentalne rezultate, iako su neka odstupanja istaknula potrebu za poboljšanjima. Dobiveni rezultati naglašavaju potencijal ovakvih sustava za skalabilne, učinkovite i kontrolirane organometalne reakcije.
Ovo istraživanje unaprjeđuje primjenu protočnih reaktorskih sustava u farmaceutskoj proizvodnji, promičući održive tehnologije sinteze
Heritage and the formation of place identity – the city of Vukovar as a case study
No full textOvaj rad istražuje ulogu baštine u oblikovanju identiteta mjesta na primjeru grada Vukovara, s posebnim naglaskom na kolektivno pamćenje i kulturni identitet. Baština se ne sastoji samo od materijalnih artefakata, nego se stvara i održava kroz kulturne aktivnosti i procese koji uključuju prijenos društvenih značenja i vrijednosti. U kontekstu Vukovara, grada koji je pretrpio velike gubitke tijekom Domovinskog rata, baština rata igra ključnu ulogu u formiranju identiteta zajednice. U prvom dijelu radu predstavljaju se teorijski okviri kolektivnog pamćenja, identiteta, mračnog i ratnog turizma nakon čega se u fokus postavljaju različite manifestacije baštine, muzeji, spomenici i komemoracije. U drugom dijelu rada, prikazuje se anketno istraživanje među stanovnicima Vukovara s ciljem utvrđivanja njihovih stavova o važnosti i ulozi baštine, kao i baštine rata u oblikovanju identiteta. Upitnik je ispunilo 282 ispitanika, a rezultati su pokazali kako različiti osobni faktori, poput dobi, obrazovanja i nacionalnosti, utječu na percepciju baštine i navike posjeta baštinskim institucijama. Zaključno, baština igra ključnu ulogu u oblikovanju identiteta Vukovaraca te treba istaknuti važnost pažljivog pristupa interpretaciji baštine rata kako bi se osigurao suživot i poštovanje neovisno o različitim mišljenjima, iskustvima i perspektivama građana.This paper explores the role of heritage in shaping identity, using the example of the city of Vukovar, with a special focus on collective memory and cultural identity. Heritage is not solely comprised of tangible artifacts; it is created and maintained through cultural activities and processes that include the transmission of social meanings and values. In the context of Vukovar, a city that suffered significant losses during the Homeland War, war heritage plays a crucial role in forming the community's identity. The first part of the paper addresses the theoretical frameworks of collective memory and identity, and describes different heritage events, museums, monuments, and commemorations. The second part of the paper contains a research conducted through a survey among the residents of Vukovar to determine their views on the importance and role of heritage, including war heritage, in shaping identity. The questionnaire was completed by 282 respondents, and the results showed that various personal factors, such as age, education, and nationality, influence the perception of heritage. In conclusion, heritage plays a key role in shaping the identity of the people of Vukovar. It is important to emphasize the necessity of a careful approach to interpreting war heritage to ensure coexistence and respect, regardless of differing opinions, experiences, and perspectives among the citizens
Numerical stress analysis of the composite steering wheel for a Formula Student competition vehicle
No full textCilj ovog završnog rada je razvoj kompozitnog volana natjecateljskog vozila Formule Student
te numerička analiza istog. U radu je izrađen CAD model, a zatim i numerički model volana te
je provedena analiza metodom konačnih elemenata korištenjem programskog paketa Abaqus.
Posebna pažnja posvećena je konstrukciji hvatišta radi postizanja potpune ergonomije,
optimizaciji oblika volana (s umetkom) te rasporedu slojeva, čime je postignuta željena krutost
uz minimalnu masu.
Pri razvoju ergonomije su sudjelovali vozači FSB Racing Team-a, dok su se postavljene sile i
zahtjevi temeljili na testiranjima i proračunima.
Numerička analiza započinje izradom numeričkog modela volana, definiranjem rubnih uvjeta,
opterećenja i rasporeda slojeva kompozitnih materijala, uz analizu čvrstoće primjenom kriterija
popuštanja Tsai-Hill i Tsai-Wu.The goal of this Bachelor's thesis is the design of the composite steering wheel of the Formula
Student competition vehicle and its numerical analysis. In the thesis, a CAD model was created,
followed by a numerical model of the steering wheel, and an analysis was performed using the
finite element method using the Abaqus software package. Special attention was paid to the
design of the grips, in order to achieve complete ergonomics, and to optimize the shape of the
steering wheel, but also to define the composite layup, which achieved the desired stiffness with
minimal mass. The ergonomics development involved drivers from the FSB Racing Team,
while the applied forces and requirements were based on testing and calculations.
The numerical analysis began with the creation of the numerical model of the steering wheel,
the definition of boundary conditions, loads, and the selection of the layup of the composite
plies, followed by a strength analysis using the Tsai-Hill and Tsai-Wu failure criteria
Prevalence of Dirofilaria sp. Nematode in Krapinsko-zagorska County
No full textD. immitis i D. repens oblići su iz koljena Nematoda, razreda Chromadorea, reda Spirurida,
porodice Onchocercidae i roda Dirofilaria. Uzročnici su invazijske bolesti, dirofilarioze koja
spada u bolesti prenosive vektorima. Najčešći nositelji su psi, međutim invazija je dokazana u
vukova, lisica, mačaka u koje se ubraja i domaća mačka, u medvjeda, pandi, dabrova, kunića,
jelena, konji, ali i ljudi. Bolest prenose komarci iz porodice Culicidae i rodova Culex, Aedes,
Ochlerotatus, Anopheles, Armigeres i Mansonia. D. immitis uzročnik je kardiopulmonalne
dirofilarioze, dok D. repens uglavnom ne uzrokuje pojavu kliničkih znakova ili se mogu javiti
nespecifični dermatološki simptomi. Obje vrste su uzročnici su zoonoza, dok je u Europi najviše
slučajeva kod ljudi uzrokovano s D. repens. Zbog svoje rasprostranjenosti po cijeloj Republici
Hrvatskoj, cilj ovog istraživanja bio je utvrditi prisutnost i vrstu Dirofilaria sp. u pasa na
području Krapinsko-zagorske županije te po potrebi tretirati pronađene rezervoare kako ne bi
predstavljali izvor invazije za druge životinje i ljude. Istraživanje je provedeno na području
Krapinsko Zagorske županije, na 110 uzoraka krvi pasa. Modificiranim Knottovim testom i
morfometrijskim odlikama je dokazana prisutnost D. repens u 1,81% uzoraka.D. immitis and D. repens are species from the phylum Nematoda, class Chromadorea, order
Spirurida, family Onchocercidae and genus Dirofilaria. They are the causative agents of an
invasive disease, dirofilariosis, which belongs to vector-borne diseases. The most common
hosts are dogs, however, invasion has been proven in wolves, foxes, cats, including domestic
cats, bears, pandas, beavers, rabbits, deer, horses, and humans. The disease is transmitted by
mosquitoes from the family Culicidae and the genera Culex, Aedes, Ochlerotatus, Anopheles,
Armigeres and Mansonia. D. immitis is the causative agent of cardiopulmonary dirofilariosis,
while D. repens mostly does not cause clinical signs or nonspecific dermatological symptoms
can occur. Both species are zoonotic agents, whereas in Europe most cases in humans are caused
by D. repens. Due to its distribution throughout the Republic of Croatia, the aim of this research
was to determine the presence and species of Dirofilaria sp. in dogs in Krapina-Zagorje County
and, if necessary, treat the proven reservoirs so they do not represent a source of invasion for
other animals and humans. The research was conducted in Krapina-Zagorska County, on 110
dog blood samples. The modified Knott's test and morphometry proved the presence of D.
repens in 1.81% of the sample
Development and realization of an entrepreneurial idea
No full textOvaj završni rad bavi se planiranjem i otvaranjem tvrtke specijalizirane za proizvodnju i prodaju visokokvalitetnog namještaja od punog drveta, uključujući stolove, stolice, krevete, dječje krevete, regale za vino, gravirane ploče i druge specifične proizvode. Glavni materijali koji će se koristiti u proizvodnji su vrhunske vrste drveta poput hrasta, oraha, bukve i ariša, čime se osigurava premium kvaliteta i dugovječnost proizvoda. Ciljana skupina kupaca su osobe i poslovni subjekti koji cijene unikatni dizajn, ručnu izradu i prirodne materijale, čime se tvrtka pozicionira na tržište kao proizvođač luksuznog namještaja.
Cilj pokretanja ove tvrtke je legalizacija postojećih djelatnosti te iskorištavanje dostupnih financijskih poticaja Europske unije za razvoj gospodarstva i samozapošljavanje. U radu su detaljno opisane faze otvaranja tvrtke, uključujući izradu poslovnog plana, analizu tržišta, procjenu troškova i potrebnih resursa, te strategije marketinga i distribucije proizvoda. Poseban naglasak stavljen je na ekološku održivost kroz korištenje certificiranog drveta i optimizaciju proizvodnih procesa kako bi se smanjio otpad.
U radu su također obrađene zakonske obveze vezane uz registraciju poduzeća, dobivanje dozvola i ostvarivanje prava na EU poticaje. Razrađena je i financijska analiza koja uključuje troškove pokretanja, projicirane prihode te vremenski okvir povrata ulaganja. Rezultati istraživanja pokazuju da postoji značajan potencijal za uspjeh ove tvrtke, zahvaljujući rastućoj potražnji za premium namještajem i podršci kroz EU programe.
Zaključno, otvaranje tvrtke za proizvodnju i prodaju namještaja od punog drveta predstavlja održiv i profitabilan poslovni pothvat, koji će doprinijeti razvoju lokalne ekonomije, stvaranju novih radnih mjesta te promicanju kvalitete i tradicije u suvremenom poslovanju.This final thesis focuses on the planning and establishment of a company specializing in the production and sale of high-quality solid wood furniture, including tables, chairs, beds, children's beds, wine racks, engraved plaques, and other specific products. The main materials used in production are premium wood types such as oak, walnut, beech, and larch, ensuring superior quality and durability. The target customer group consists of individuals and businesses that appreciate unique design, handcrafted production, and natural materials, positioning the company in the market as a manufacturer of luxury furniture.
The goal of starting this company is to legalize existing activities and take advantage of available European Union financial incentives for economic development and self-employment. The thesis provides a detailed description of the phases involved in launching the company, including business plan development, market analysis, cost estimation, and required resources, as well as marketing and product distribution strategies. Special emphasis is placed on ecological sustainability through the use of certified wood and the optimization of production processes to minimize waste.
The study also covers legal obligations related to company registration, obtaining permits, and securing EU funding. A financial analysis is included, detailing startup costs, projected revenues, and the expected return on investment timeline. Research findings indicate significant potential for the company’s success, driven by the growing demand for premium furniture and support from EU programs.
In conclusion, establishing a company for the production and sale of solid wood furniture represents a sustainable and profitable business venture that will contribute to local economic growth, job creation, and the promotion of quality and tradition in modern business
Optimisation of layup and layer orientation of the Formula Student composite chassis
No full textU ovom radu je prikazan pregled pravilnika, opis korištenih materijala i teorija iza proračuna kompozitnih struktura. Također, prikazana je strukturalna razrada monokoka Formula Student bolida. Strukturalna razrada uključuje proračun rasporeda slojeva metodom konačnih elemenata, izradu i ispitivanje uzoraka strukture šasije te proračun jednakovrijednosti odabrane kompozitne strukture u odnosu na pravilnikom definiranu čeličnu cijevnu šasiju. Detaljno su opisani koraci pri odabiru rasporeda slojeva monokoka te proračunati svi dijelovi nove, odabrane kompozitne strukture monokoka. Ispitivanjima uzoraka i proračunima dokazana je sigurnost monokoka i samim time vozača koji će voziti bolid. Konačno, provedena je analiza metodom konačnih elemenata torzijske krutosti šasije i naprezanja šasije kod različitih uvjeta vožnje bolida.This paper presents an overview of the regulations, a description of the materials used, and the theoretical background behind the calculation of composite structures. It also includes the structural development of a Formula Student monocoque chassis. The structural analysis involves the calculation of the layup using the finite element method, fabrication and testing of chassis structure samples, as well as the equivalence analysis of the selected composite structure in comparison to the steel space frame defined by the regulations. The steps taken in selecting the monocoque layer configuration are described in detail, and all components of the newly selected composite monocoque structure are calculated. Through sample testing and analytical calculations, the safety of the monocoque and consequently, the safety of the driver has been demonstrated. Finally, a finite element analysis of the chassis torsional stiffness and stress distribution under various driving conditions was performed
Techno-economic analysis of providing ancillary services to the power grid using heat pumps and thermal storage
No full textRad donosi tehno-ekonomsku analizu optimiziranog upravljanja sustava dizalica topline i toplinskih spremnika, pri čemu je razvijen iterativni model linearnog programiranja. U modelu se koeficijent učinkovitosti (COP) postupno prilagođava kroz nekoliko uzastopnih koraka kako bi se postigao stvaran prikaz ovisnosti o vanjskoj i polaznoj temperaturi. Uzeta je u obzir i tržišna dinamika cijena električne energije koja omogućuje optimizacijsko preusmjeravanje potrošnje u razdoblja s povoljnijim cijenama. Model je testiran na stvarnim podacima i različitim konfiguracijama sustava dizalice topline i spremnika. Rezultati pokazuju uštede u razdobljima s velikim oscilacijama cijena i negativnim cijenama električne energije. Provedena je tehno-ekonomska analiza isplativosti ulaganja za fizičke osobe, temeljena na metodi jednostavne stope povrata pri čemu su utvrđeni potencijalni godišnji povrati ovisno o promjenama cijena električne energije. Temeljna vrijednost ovog rada leži u proširenoj tehno-ekonomskoj analizi na energetske zajednice. Agregacijom više kućanstava ukupna fleksibilnost postiže vrijednosti koje zadovoljavaju minimalni prag za tržišta pomoćnih usluga. Primjer u radu pokazuje da energetska zajednica od 60 članova, može unutar 20 godina zaraditi 372.937,80 € (u srednjem scenariju) od smanjenja vršnog opterećenja i optimizacije. Period povrata investicije je ispod 7 godine te se istodobno smanjuju mrežna vršna opterećenja za 38,29 MWh po sezoni grijanja. Tako sustav dizalice topline i toplinskog spremnika prelazi iz pasivnih potrošača u aktivne sudionike elektroenergetskog sustava, a lokalne energetske zajednice postaju ključan mehanizam za motiviranje fleksibilnosti krajnjih korisnika i ubrzanje integracije obnovljivih izvora.In the master's thesis, a techno-economic analysis of optimized management of heat pump and thermal storage systems was conducted, during which an iterative linear programming model was developed. In the model, the coefficient of performance (COP) is gradually adjusted through several successive steps to achieve a realistic representation of its dependence on outdoor and supply temperatures. The model also takes into account the market dynamics of electricity prices, enabling optimization by shifting consumption to periods with more favorable prices. The model was tested using real-world data and various configurations of heat pump and storage systems. The results show savings during periods with significant price fluctuations and negative electricity prices. A techno-economic feasibility analysis for private individuals was conducted, based on the simple payback method, identifying potential annual returns depending on changes in electricity prices. The core value of this work lies in the extended techno-economic analysis applied to energy communities. By aggregating multiple households, the overall flexibility reaches thresholds that satisfy the minimum requirements for participation in ancillary service markets. The example presented in the thesis shows that an energy community of 60 members can, over a period of 20 years, earn €372.937,80 (in the medium scenario) through peak load reduction and optimization. The investment payback period is under 7 years, while network peak loads are simultaneously reduced by 38,29 MWh per heating season. Thus, heat pump and thermal storage systems transition from passive consumers to active participants in the power system, and local energy communities become a key mechanism for encouraging end-user flexibility and accelerating the integration of renewable energy sources