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Optical separation in e-waste recycling
No full textSvake godine na tržište se stavlja velika količina električne i elektroničke opreme, a istovremeno se mala količina električnog i elektroničkog otpada pravilno prikuplja i reciklira. U EE-otpadu su sadržane velike količine opasnih tvari, ali i vrijednih sirovina. Nakon primarnog uklanjanja opasnih tvari, ovaj otpad se usitnjava i razdvaja. U ovom diplomskom radu su navedeni i opisani postupci usitnjavanja i razdvajanja EE-otpada. Detaljno je opisan proces recikliranja kućanskih uređaja. Optičko razvrstavanje je napredan postupak koji se koristi za razvrstavanje usitnjenog EE-otpada. Optički separator je uređaj visoke osjetljivosti koji može razvrstavati EE-otpad na temelju boje, oblika i transparentnosti. U radu su opisane njegove mogućnosti i prednosti te ograničenja i nedostaci.
U eksperimentalnom dijelu ovog diplomskog rada ispitane su mogućnosti optičkog separatora na uzorku usitnjenog EE-otpada te je napravljena usporedba s podatcima dobivenim postupkom ručne separacije.Every year, a large amount of electrical and electronic equipment is placed on the market, while at the same time a small amount of electrical and electronic waste (WEEE) is properly collected and recycled. E-waste contains large quantities of hazardous substances, but also valuable raw materials. After the primary removal of hazardous substances, this waste is shredded and separated. In this master thesis the procedures of shredding and separation of e-waste are listed and described. The process of recycling household appliances is described in detail. Optical sorting is an advanced process used to sort shredded e-waste. An optical separator is a highly sensitive device that can sort e-waste based on color, shape, and transparency. In this thesis capabilities and advantages are described as well as its limitations and disadvantages.
In the experimental part of the master thesis the possibilities of the optical separator on the sample of crushed EE-waste were examined and a comparison was made with the data obtained by the manual separation process
Die casting mould design for an aluminium alloy engine mount
No full textVisokotlačno lijevanje je značajan proizvodni postupak koji se primjenjuje u raznim industrijama. Bitna komponenta postupka visokotlačnog lijevanja je kalup. Oblik i karakteristike kalupa utječu na značajke konačnog proizvoda.
U uvodnom dijelu ovog rada dan je kratak pregled povijesnog razvoja postupka lijevanja, a zatim su ukratko pojašnjeni sami postupci lijevanja.
Nakon pokrivenog teorijskog dijela lijevanja, prikazani su interni standardi konstrukcijskih rješenja komponenata kalupa. Za sve bitne komponente objašnjena je njihova uloga u kalupu te u samom procesu lijevanja. Za sve zahtjevnije komponente te za komponente kalupa za koje se smatralo potrebnim, dat je primjer konstrukcijskog rješenja.
U nastavku prikazani su zahtjevi procesa lijevanja, zahtjevi za odljevak te zahtjevi za stroj. U ovom dijelu je također verificiran sam model te izrađeni su ulijevna grana i preljevni džepovi s odzračnicima. Provedeni su svi neophodni proračuni za ovaj korak.
Na kraju ovog rada prikazane su standardne komponente koje su se koristile u projektiranju ovog kalupa. Također, prikazani su problemi koji su se javili u probnom lijevanju te način na koji su otklonjeni.
Sveukupnu nacrtnu dokumentaciju ovog kalupa moguće je pronaći na kraju ovog rada.Die casting is an important manufacturing process used in various industries. An essential component of the high-pressure die casting process is the mold. The shape and characteristics of the mold affect the characteristics of the final product.
In the introductory part of this paper, a brief overview of the historical development of the casting process is given, and then the casting processes themselves are briefly explained.
After the theoretical part of casting has been covered, the internal standards of the structural solutions of the mold components are presented. For all important components, their role in the mold and in the casting process itself is explained. For all the more complex components, and for the mold components for which it was necessary, an example of the design solution is given.
Below are the casting process requirements, casting requirements, and machine requirements. In this part, the model itself was also verified; runner, gate and overflow with vents were made. All necessary calculations for this step were performed.
At the end of this paper, the standard components used in the design of this mold are shown. Also, the problems that occurred in the test casting and the way in which they were eliminated are presented.
The entire documentation of this mold can be found at the end of this thesis
Project of low-floor electric minibus
No full textPolazište za realizaciju ovog projekta su do sada obavljeni razvojni zadaci od strane Katedre za motore i vozila, Fakulteta strojarstva i brodogradnje, Sveučilišta u Zagrebu. U okviru diplomskog rada je napravljen pretprojekt novog multifunkcionalnog niskopodnog minibusa kojim se sagledao koncept vozila, aktivnosti potrebne za pokretanje proizvodnje i plasmana vozila na tržište. Analizirana je situacija na tržištu s ciljem određivanja konkurencije novog vozila, veličine i vrijednosti tržišta, te tržišni potencijal proizvoda. Razmatrani su mogući modeli komercijalizacije projekta minibusa.
Nadalje, tijekom pisanja ovog rada napravljen je pregled i usporedba linija javnog gradskog prijevoza te drugih konkurentnih prijevoznih sredstva. Zaključno, izračunata je potrošnja energije po jedinici puta za sve oblike javnog prijevoza, a sve kako bi se utvrdila isplativost supstitucije postojećih oblika javnog prijevoza s multifunkcionalnim niskopodnim vozilom, MUNIV-om.A starting point for the realisation of this project derives from the development tasks presented by the Department for engines and vehicles, Faculty of mechanical engineering and naval architecture, University of Zagreb.
Within the scope of the master thesis, a pre-project of a new multifunctional low-floor minibus was formed, which outlined the concept of the vehicle and the activities required to initiate the production, product placement and marketing of the vehicle.
A market analysis was performed to determine product competition, size and value of the market and the market potential of the product. Possible models for commercialisation of the minibus project were considered.
In addition to the abovementioned analysis, an overview and comparison of available public transport lines and other competitive means of transport were made.
In conclusion, the energy consumption per unit of transportation was calculated for all modes of public transport with the main objective to determine the cost-effectiveness of replacing existing forms of public transport with a multifunctional low-floor vehicle, MUNIV
Water-to-water heat pump project for heating and cooling of scientific and educational institution
No full textRad se zasniva na stvarnom projektu za objekt u Zagrebu. Za potrebe grijanja i hlađenja znanstveno-obrazovne ustanove korisne površine 10400 m2 projektiran je energetski učinkovit sustav s dizalicom topline podzemna voda-voda. Toplinski izvor/ ponor je voda iz podzemnog bunara. Predviđen je temperaturni režim 45/40 °C za grijanje, te 7/12 °C za hlađenje, a u prijelaznom periodu prostori se hlade pasivno podzemnom vodom. U radu je dan pregled projektnog toplinskog opterećenja prema HRN EN 12831 i projektnog rashladnog opterećenja prema VDI 2078. Proračunata je godišnja potrebna energija za grijanje i godišnja potrebna energija za hlađenje prema HRN EN 13790. Prikazana je shema predviđenog sustava te je napravljen proračun i izbor komponenti koje uključuju protočne crpke, međuizmjenjivač, isparivač i kondenzator dizalice topline i akumulacijski spremnik. Završno je opisana mogućnost pasivnog hlađenja, regulacija sustava, te su dani zaključci i prijedlozi daljnjih razmatranja.The thesis is based on a real project for building in Zagreb. An energy efficient heating and cooling system with groundwater to water heat pump has been designed for the purpose of heating and cooling a scientific and educational institution with a net usable area of 10400 m2. The heat source/sink is water from an underground well. A temperature regime of 45/40 °C is designated for heating and 7/12 °C for cooling, while during transitional periods, the spaces are passively cooled using groundwater. The paper provides an overview of the design heating load according to HRN EN 12831 and the design cooling load according to VDI 2078. The annual energy demand for heating and cooling is calculated according to HRN EN 13790. A schematic of the proposed system is presented, accompanied by calculations and component selection, including flow pumps, a heat exchanger, the evaporator and condenser of the heat pump, and a buffer tank. Finally, the possibility of passive cooling and system regulation is described, along with conclusions and suggestions for future considerations
Analysis and design of a teaching aid for vibration theory
No full textVibracije su neizostavni dio industrije, a u današnje vrijeme kada sve ubrzano napreduje bitno je znati rješavati probleme koji se stavljaju pred inženjere. Kako bi problem vibracija bio što lakše rješiv bitno je od početka razumjeti kako vibracije nastaju i koji su postupci rješavanja istih.
Mehaničke vibracije su periodična ili kvaziperiodična gibanja mehaničkih sustava koja mogu nastati uslijed vanjskih uzbuda ili unutarnjih dinamičkih svojstava sustava. Isaac Newton svojim je drugim zakonom postavio temeljnu dinamiku čitave klasične mehanike, uključujući i analizu vibracija. Jean Baptiste le Rond d'Alembert tu je osnovu produbio razvojem d'Alembertova načela i matematičkih metoda za rješavanje gibanja niza praktičnih vibracijskih sustava, osobito kontinuiranih. Zajedno, njihova razmatranja omogućuju razradu općih jednadžbi za proučavanje, kontrolu i prigušenje mehaničkih vibracija te čine temelj suvremene teorije oscilacija.
U ovom radu dan je pregled triju koncepata nastavnog pomagala za razmatranje i proučavanje u nastavi koji će studentima olakšati shvaćanje vibracija. Svaki koncept se razlikuje po osnovnim dijelovima uređaja kao što su linearna vodilica, vozičak i uteg (masa). Nakon pregleda svih koncepata odabran je najbolji koncept koji je i konstrukcijski razrađen. Odabrani koncept razrađen je analitički te parametriziran i programiran u Matlabu.Vibrations are an unavoidable part of today's industry, where everything is developing at fast pace. As engineers, it's important to be able to deal with presented challenges. For a better understanding of vibration problems it's crucial to understand how they occur and what necessary steps are needed to solve them.
Mechanical vibrations are periodic or quasi-periodic movements of mechanical systems that can appear due to external excitations or internal dynamic properties of the system. Isaac Newton's second law laid the foundation for the dynamics of classical mechanics, including vibration analysis. Jean-Baptiste le Rond d'Alembert development d'Alembert's principle and mathematical methods for solving the motion of various practical vibration systems, especially continuous vibration systems. Together, their work enabled the development of general equations for studying, controlling, and damping mechanical vibrations, which form the foundation of modern oscillation theory.
In this paper, an overview of three teaching approaches to vibration is given, which will make students' understanding of vibrations easier. Each concept differs from the others based on primary components such as linear guide, carriage and mass. After reviewing all concepts, the best one was chosen and structurally elaborated. The chosen concept is explored analytically, parametrized, and programmed in MATLAB
Anaysis of healthy food availability and product placement in different retail formats
No full textNačin na koji je zdrava hrana dostupna i pozicionirana u prodavaonicama može značajno utjecati na prehrambene izbore potrošača. Ovaj rad istražuje ulogu maloprodajne ponude kao čimbenika koji pridonosi oblikovanju prehrambenih navika, s naglaskom na dostupnost i pozicioniranje zdrave hrane. Istraživanje je provedeno metodom promatranja u odabranim maloprodajnim oblicima u Zagrebu. Istraživanje je uključivalo bilježenje fizičkog rasporeda proizvoda, omjera zdrave i nezdrave hrane, cijena te jasnoće označavanja proizvoda. Rezultati pokazuju da zdrava hrana često nije dovoljno vidljiva, zauzima manji udio prostora i često je skuplja u usporedbi s nezdravim proizvodima. Rad ukazuje na izazove u maloprodaji te mogućnosti za poboljšanje dostupnosti zdravijih prehrambenih izbora.The availability and positioning of healthy food in stores can significantly influence consumers dietary choices and thereby shape their eating habits. This paper investigates the role of retail offerings as a factor contributing to the formation of dietary habits, with a focus on the availability and positioning of healthy food. The research was conducted using an observational method in selected retail formats in Zagreb. The study involved recording the physical arrangement of products, the ratio of healthy to unhealthy food, prices, and the clarity of product labeling. The results show that healthy food is often not sufficiently visible, occupies a smaller share of shelf space, and is often more expensive compared to unhealthy products. The paper highlights challenges in retail and suggests possibilities for improving the availability of healthier food choices
Development of solutions for reducing deformations in the production of tools for glass packaging
No full textTijekom procesa tokarenja, kod stezanja obratka u steznoj glavi, često dolazi do pojave deformacija, koje mogu biti elastične i plastične. Te deformacije mogu negativno utjecati na dimenzijsku točnost što izravno utječe na kvalitetu gotovih proizvoda. U ovom radu analiziran je problem deformacija obratka u steznoj glavi tijekom tokarenja dijelova alata koji se koriste u proizvodnji staklene ambalaže u tvrtki OMCO Croatia d.o.o. Predložena su moguća tehnička rješenja za smanjenje ili potpuno uklanjanje tih deformacija te je procijenjena primjenjivost i utjecaj predloženih rješenja na točnost obrade, kvalitetu proizvoda i učinkovitost u stvarnom proizvodnom okruženju.During the turning process, clamping the workpiece in the chuck often leads to deformations, which can be both elastic and plastic. These deformations can negatively affect dimensional accuracy, which directly impacts the quality of the final product. This paper analyzes the problem of workpiece deformation in the chuck during the turning of tool parts used in the production of glass packaging at the company OMCO Croatia d.o.o. Possible tehnical solutions are proposed to reduce or completely eliminate these deformations, and the applicability and impact of the proposed solutions on machining accuracy, product quality, and efficiency in a real production environment are evaluated
The distribution of botulinum toxin type A in supraspinal regions involved in nociception
No full textBotulinum toksin tipa A (BoNT/A), iako jedan od najpotentnijih poznatih otrova u prirodi, već desetljećima ima važno mjesto u terapiji brojnih stanja, od mišićnih distonija do kronične boli. Njegov antinociceptivni učinak intenzivno se istražuje, osobito u kontekstu djelovanja na kronična bolna stanja poput neuropatske boli i kronične migrene, za koju je BoNT/A odobren kao terapijsko sredstvo. U ovom radu analizirana je distribucija BoNT/A u središnjem živčanom sustavu nakon njegove periferne primjene u stražnju šapu štakora. Korištenjem imunohistokemijske metode detektiran je signal pokidanog SNAP-25 proteina, koji predstavlja indirektni pokazatelj proteolitičke aktivnosti, a time i prisustva BoNT/A. Signal je zabilježen u periakveduktalnoj sivoj tvari (PAG) i locus coeruleusu (LC), regijama poznatim po važnoj ulozi u supraspinalnoj modulaciji boli. Ovi rezultati upućuju na to da BoNT/A, nakon periferne primjene, retroaksonalnim transportom dolazi do spinalne razine, a potom se potencijalno i trans-sinaptički prenosi do viših, supraspinalnih struktura. Izostanak signala prilikom primjene specifičnog antitoksina za BoNT/A dodatno potvrđuje mogućnost trans-sinaptičkog prijenosa, budući da antitoksin neutralizira samo izvanstanični BoNT/A. Dobiveni rezultati doprinose razumijevanju složenog središnjeg mehanizma djelovanja na bol, ali ukazuju i na moguće rizike s obzirom na distribuciju toksina na udaljena mjesta, što je potrebno dodatno istražiti.Botulinum toxin type A (BoNT/A), although one of the most potent known toxins, has held an important place in the treatment of various conditions for decades, ranging from muscle dystonias to chronic pain. Its antinociceptive effect has become increasingly prominent, particularly in the context of neuropathic pain and chronic migraine, for which BoNT/A has already been approved as a therapeutic agent. This study analyzes the distribution of BoNT/A within the central nervous system following its peripheral administration into the hind paw of rats. Using immunohistochemistry, a signal of cleaved SNAP-25 protein was detected, serving as an indirect marker of BoNT/A’s proteolytic activity. The signal was observed in the periaqueductal gray (PAG) and the locus coeruleus (LC), regions known for their crucial role in supraspinal pain modulation. These findings suggest that BoNT/A, after peripheral administration, reaches the spinal level via retrograde axonal transport and may subsequently be transmitted trans-synaptically to higher, supraspinal structures. A reduction in signal intensity following the application of a specific BoNT/A antitoxin further supports the possibility of trans-synaptic transmission, as the antitoxin neutralizes only extracellular BoNT/A. The obtained results contribute to the understanding of the complex central mechanism of action on pain, but also indicate potential risks regarding the distribution of the toxin to distant sites, which requires further investigation
Mechanochemical activation by grinding with cyclodextrins as a strategy to enhance the solubility of cinnarizine
No full textCinarizin je lijek, po strukturi derivat piperazina, koji ima antihistaminsko, antiserotonergično,
antidopaminergično djelovanje, a ujedno je i blokator kalcijevih kanala koji pokazuje ograničenu, pH ovisnu
topljivost in vitro i visoka permeabilnost in vivo. Stvaranje inkluzijskih kompleksa s ciklodekstrinima jedan
je od načina kojima se može utjecati na topljivost uklopljenog lijeka. U ovom diplomskom radu istražen je
utjecaj inkluzijskih kompleksa cinarizina s β-ciklodekstrinom, hidroksipropil-β-ciklodekstrinom i
sulfobutileter-β-ciklodekstrinom, pripremljenih metodom mljevenja, na brzinu i opseg in vitro otapanja
cinarizina u simuliranom duodenalnom mediju pri pH 4,5. Za potrebe kvantitativnog određivanja cinarizina
u uzorcima razvijena je i validirana UV/Vis spektroskopska metoda. Mljevenje je provedeno na
visokoenergijskom vibracijskom mlinu pri frekvencijama 20 i 30 Hz u različitim vremenima. Nastajanje
ciklodekstrinskih kompleksa cinarizina praćeno je primjenom termoanalitičkih metoda, a in vitro oslobađanje
CIN provedeno je na uređaju s lopaticom. Kao ključni tehnološki parametar s utjecajem na opseg interakcije
lijeka i ciklodekstrina pokazala se frekvencija mljevenja, a kompleks sa hidroksipropil-β-ciklodekstrinom
pripremljen mljevenjem tijekom 20 minuta na 30 Hz pokazuje najveći potencijal za daljnju primjenu. Pri
tome, funkcionalnost ovog kompleksa potrebno je dalje ispitati primjenom složenijih, biorelevantnih metoda
kojima se precizno oponašaju uvjeti prisutni u probavnom sustavu.Cinnarizine is a drug, a derivative of piperazine, which exhibits antihistaminic, antiserotonergic, and
antidopaminergic effects. It is also a calcium channel blocker that demonstrates limited, pH-dependent
solubility in vitro and high permeability in vivo. The formation of cyclodextrin inclusion complexes is an
effective approach to enhance the solubility of the incorporated drug. In this thesis, the influence of the
inclusion complexation of cinnarizine with β-cyclodextrin, hydroxypropyl-β-cyclodextrin, and sulfobutyl
ether-β-cyclodextrin, prepared using the grinding method, on the rate and extent of in vitro dissolution of
cinnarizine in a simulated duodenal medium at pH 4.5 was investigated. A UV/Vis spectroscopic method was
developed and validated to quantitatively determine cinnarizine in samples prepared by grinding. Grinding
was conducted on a high-energy vibration mill at 20 and 30 Hz frequencies, applying various processing
times. The formation of cyclodextrin complexes with cinnarizine was monitored using thermoanalytical
methods, and in vitro release of CIN was conducted using a paddle apparatus. The milling frequency was
identified as a crucial technological parameter affecting the degree of drug-cyclodextrin interaction, and the
complex with hydroxypropyl-β-cyclodextrin prepared by milling for 20 minutes at 30 Hz demonstrated the
highest enhancement of in vitro dissolution properties. However, the functionality of this complex requires
further testing using more intricate, biorelevant methods that accurately replicate the conditions present in
the digestive system
Development of an application for real-time analysis of lower extremity kinematics in daily activities using smartphone sensors
No full textCilj ovog završnog rada je istražiti mogućnost primjene senzora pametnog telefona za analizu kinematike donjih ekstremiteta tijekom svakodnevnih aktivnosti. U radu se detaljno obrađuju izrazi kinematike krutih tijela, koji su ključni za razumijevanje biomehaničkih aspekata ljudskog pokreta, a analiza podataka prikupljenih iz akcelerometra, giroskopa, magnetometra i GPS senzora omogućuje precizno praćenje gibanja u stvarnom vremenu. Posebna je pažnja posvećena razvoju vlastite aplikacije koja osigurava jednostavno prikupljanje, filtriranje i obradu podataka, pri čemu se istražuje utjecaj različitih parametara mjerenja na konačnu točnost rezultata. Rad je logički podijeljen u tri glavna dijela. U prvom dijelu izlaže se teorijska podloga, koja obuhvaća stručni dio biomehaničke analize i kinematike, s detaljnom obradom matematičkih i fizičkih osnova pokreta. Drugi dio rada posvećen je razvoju same aplikacije i izboru korištenog hardvera (eng. hardware), što omogućuje učinkovito prikupljanje i obradu podataka u stvarnom vremenu. U završnom, eksperimentalnom dijelu, provodi se testiranje razvijenog sustava kroz analizu pokreta poput hodanja, trčanja i drugih aktivnosti, pri čemu se dobiveni rezultati uspoređuju s idealnim slučajem snimljenim u kontroliranim uvjetima, kako bi se potvrdila pouzdanost i preciznost pristupa. Dobiveni rezultati ukazuju na visoku točnost i primjenjivost sustava temeljenog na senzorskim podacima pametnih telefona, čime se otvaraju nove mogućnosti za primjenu u rehabilitaciji, sportu i daljnjim znanstvenim istraživanjima kinematike ljudskog pokreta.The objective of this final thesis is to investigate the possibility of using smartphone sensors
for the analysis of lower extremity kinematics during everyday activities. The paper thoroughly
examines the expressions of rigid body kinematics, which are crucial for understanding the
biomechanical aspects of human motion, and analyses data collected from accelerometers,
gyroscopes, magnetometers, and GPS sensors to enable precise real-time movement tracking.
Particular attention is devoted to the development of a custom application that ensures easy
data collection, filtering, and processing, while also exploring the impact of various
measurement parameters on the final accuracy of the results.
The work is logically divided into three main parts. The first part presents the theoretical
background, covering the technical aspects of biomechanical analysis and kinematics with a
detailed treatment of the mathematical and physical fundamentals of movement. The second
part is dedicated to the development of the application and the selection of the utilized
hardware, which enables efficient real-time data collection and processing. In the final
experimental phase, the developed system is tested through the analysis of movements such as
walking, running, and other activities, with the obtained results compared to an ideal case
recorded under controlled conditions, in order to validate the reliability and accuracy of the
approach.
The results indicate a high level of accuracy and applicability of the system based on
smartphone sensor data, thereby opening new possibilities for applications in rehabilitation,
sports, and further scientific research on human movement kinematics