Repository of Faculty of Metallurgy University of Zagreb
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Fire protection systems and testing of the fire alarm panel with evacuation exercise
No full textOd samog otkrića vatre i njenog potencijala za širenje, pojavila se potreba za pronalaženjem načina i metoda za što brže i učinkovitije gašenje požara. Proučavanjem procesa gorenja i širenja vatre zaključeno je da je za zaustavljanje požara potrebno ukloniti jedan od čimbenika gorenja. Upravo na tom principu rade sustavi za gašenje požara. Zaštita od požara neophodna je u svim segmentima društva, što je dovelo do potrebe za zakonskom regulacijom kroz Zakon o zaštiti od požara. Uz samo gašenje razvijene su i u primjeni su razne mjere zaštite od požara. Mjere se svode na edukacije djelatnika, instalacije sustava za gašenje požara i ugradnju vatrodojavnih sustava. Zakonska regulativa s druge strane propisuje obveze za poslodavce, kao što je ažurno testiranje, održavanje i servisiranje tih sustava. Sustav zaštite od požara mora se jednom godišnje ispitati od strane ovlaštene tvrtke, a poslodavac mora svake dvije godine provesti vježbu evakuacije i arhivirati zapisnik o provedenoj vježbi. Kroz ovaj rad prati se ispitivanje sustava vatrodojave u tvrtki Zubak Grupa d.o.o., pri čemu su ustanovljeni nedostatci, te su poduzete korektivne radnje. Mjereno je vrijeme reakcije pojedinih odjela prije i nakon servisa sustava. Time se pokazalo koliko su sustavi za gašenje požara bitni za sigurnost ljudi te koliko nedostatak u sustavu može otežati evakuaciju korisnika iz građevine ukoliko svi dijelovi sustava ne funkcioniraju ispravno.Since the discovery of fire and its potential to spread, there has been a need to find ways and methods to extinguish fires as quickly and efficiently as possible. By studying the combustion process and the spread of fire, it was concluded that it is necessary to remove one of the burning factors in order to stop the fire. Fire extinguishing systems work on exactly this principle. Fire protection is necessary in all areas of society, which led to the need for legal regulation through the fire protection act. In addition to extinguishing the fire itself, various fire protection measures have been developed and are in use. The measures are limited to the training of employees, the installation of fire extinguishing systems and the installation of fire alarm systems. The statutory regulations in turn impose obligations on employers, such as up-to-date testing, maintenance and servicing of these systems. The fire protection system must be tested once a year by an authorized company, and the employer must carry out an evacuation drill every two years and archive a record of the drill on file. Through this work, the testing of the fire alarm system in Zubak Grupa d.o.o. is monitored and deficiencies have been identified and corrective action taken. The response time of each department was measured before and after the system was serviced. This showed how important fire extinguishing systems are for people's safety and how a defect in the system can make it difficult to evacuate users from the building if not all parts of the system are working properly
Skrućivanje i karakterizacija aluminij-magnezij-litij legure
No full textThe continuous development of innovative materials with improved functional properties is needed to meet the demands of modern transport industry. Given that previous research did not cover aluminum (Al) alloys with combined additions of magnesium (Mg) and lithium (Li), a contemporary approach in design and synthesis of an Al-Mg-Li alloy was applied. The research was performed under the basic assumption that the solidification sequence and microstructure development can be affected by the chemical composition, thermodynamic parameters, and processing parameters. A proper correlation of these parameters should result in an alloy with improved properties in the as-cast condition.Potreban je kontinuirani razvoj inovativnih materijala s poboljšanim funkcionalnim svojstvima kako bi se zadovoljili zahtjevi moderne transportne industrije. S obzirom da dosadašnjim istraživanjima nisu obuhvaćene legure aluminija (Al) s kombiniranim dodacima magnezija (Mg) i litija (Li), primijenjen je suvremeni pristup u razvoju i sintezi legure Al-Mg-Li. Istraživanje je provedeno pod osnovnom pretpostavkom da na slijed skrućivanja i razvoj mikrostrukture mogu utjecati kemijski sastav, termodinamički i procesni parametri. Ispravna korelacija ovih parametara trebala bi rezultirati slitinom s poboljšanim svojstvima u lijevanom stanju
Testing the properties of recycled DE-OX aluminium alloy for steel deoxidation
No full textU ovim diplomskom radu ispitan je reciklirajući potencijal aluminija na primjeru tvrtke CIAL d.o.o. kao jedine ljevaonice aluminija na području Republike Hrvatske ovlaštene za oporabu i pretaljivanje metalne aluminijske ambalaže – limenki. Istraživanje je provedeno u svrhu određivanja otpornosti na degradaciju uzorka DE-OX legure koja se u obliku ingota koristi za dezoksidaciju čelika. Uvjeti ubrzane degradacije simulirani su uranjanjem uzoraka u EXCO otopinu u vremenskim intervalima od 5, 24, 48, 72 i 96 sati. Stabilnost legure procijenjena je karakterizacijom kemijskog sastava, mikrostrukture i mikrotvrdoće uzoraka prije i nakon uranjanja. Kemijski sastav uzorka nalazi se unutar granica propisanih deklaracijom proizvođača. Kombinacijom rezultata proračuna ravnotežnog i neravnotežnog slijeda skrućivanja s rezultatima metalografske analize određen je slijed skrućivanja te identificirane intermetalne faze prisutne u metalnoj osnovi primarnog αAl. Rezultati procjene stabilnosti DE-OX legure ukazuju na porast pH vrijednosti otopine te nastanak i porast pukotina s vremenom zadržavanja uz minimalni gubitak mase. Porast vrijednosti pH otopine posljedica je kemijskih reakcija i izmjene iona između ispitivane površine uzorka i EXCO otopine, dok su nastanak pukotina i njihovo interdendritno napredovanje posljedica razlike u potencijalu između metalne osnove i intermetalnih faza. Minimalni gubitak mase ukazuje na nastanak i zadržavanje sloja korozijskih produkata. Približno slične vrijednosti mikrotvrdoće izmjerene uz ispitivanu površinu uzoraka nakon izlaganja ukazuju na stabilnost i zaštitnu ulogu sloja korozijskih produkata.In this work, the recycling potential of aluminum was examined using the example of the company CIAL d.o.o., which is the only aluminum foundry in the Republic of Croatia authorized to recover and remelt metallic aluminum packaging - cans. The study was performed to determine the degradation resistance of a DE-OX alloy used in the form of ingots for steel deoxidation. Accelerated degradation conditions were simulated by immersing the samples in EXCO solution at time intervals of 5, 24, 48, 72 and 96 hours. The stability of the alloy was evaluated by characterizing the chemical composition, microstructure and microhardness of the samples before and after immersion. The chemical composition of the sample is within the limits specified in the manufacturer's declaration. By combining the results of the thermodynamic equilibrium and non-equilibrium calculations with the results of the metallographic analysis, the solidification sequence and the intermetallic phase present in the primary αAl matrix were determined. The results of degradation testing show an increase in the pH value of the EXCO solution as well as the nucleation and propagation of cracks with increasing exposure time. At the same time, a minimal loss of mass was observed during the experiment. The increase in the pH of the solution is the result of chemical reactions and ion exchange between the tested surface of the sample and the EXCO solution, while the formation of cracks and their interdendritic propagation is due to the difference in electrochemical potential between the matrix and the intermetallic phases. Minimal mass loss indicates the formation and retention of a layer of corrosion products. The approximately equal values of microhardness measured along the tested surface of the samples after exposure indicate the stability and protective role of the layer
Investigation of recycled AlSi9Cu3(Fe) alloy
No full textDue to European Union legislative and recently the difficulties faced by casting manufacturers, more and more attention is focused on raw materials. Raw materials are found at the beginning of all industrial value chains. These critical (CRMs) and strategic raw materials (SRMs) are often indispensable inputs for a wide set of strategic sectors including renewable energy, the digital industry, the space and defence sectors, health sector all connected to the metal industry. Aluminium and its alloys plays an important CRMs and SRMs. Standard aluminium alloy AlSi9Cu3(Fe) (EN AC 46000) is widely used in the automotive and transport industry. High mechanical properties such as strength and hardness, as well as elongation and corrosion resistance are the main advantages of AlSi9Cu3(Fe) alloy. The functional and useful properties of aluminium cast alloys are dependent from the chemical composition, melt treatment, solidification rate, casting process and potential heat treatment. Most of them are conditioned by the microstructural development. This paper investigates the recycling potential of AlSi9Cu3(Fe) alloy using completely return material without any additions or refining. The presence of wide range of alloying elements AlSi9Cu3(Fe) alloys indicates development α-Al15Si2M4 (M= Cr, Fe, Mn, Mo), β-Al5FeSi, Al2Cu and even more complex one such as Al3Cu2Mg9Si7 using theoretical modelling. Complex solidification path indicates primary aluminium αAl, eutectic phase αAl+βSi, intermetallic phase on the iron base in Al5FeSi and “Chinese script” morphology, intermetallic phase on the magnesium and copper base such as Mg2Si and Al2Cu, and complex intermetallic such as Al8Mg3FeSi2 and Al5Mg8Si2Cu2 phases. Thermodynamic effects of elements interaction during solidification sequence significantly influence on solidification path and manner. Although the investigated samples maintain high tensile strength and elongation, slight degradation in chemical composition and therefore in thermodynamic effect, significantly influence on microstructure development. In despite of chemical composition degeneration, obtained microstructure was correct and therefore justified achieved high mechanical properties. Therefore, on the base of thermodynamic and microstructural investigation of the secondary AlSi9Cu3(Fe) alloy indicated raw material as a quality charge material with good application and recycling potential
The effects of implanted copper on human health
No full textBakar je esencijalni element koji se u ljudskom organizmu nalazi u mikro koncentraciji, a neophodan je za normalno funkcioniranje ljudskog organizma. Povišena ili smanjena koncentracija bakra u organizmu dovodi do raznih poremećaja koji posljedično mogu uzrokovati teške bolesti i otkazivanje organa, a ponekad i smrt. Bakar je jedan od najkorištenijih metala koje čovjek upotrebljava u svim sferama svoga života. Zbog važnosti uloge bakra u tijelu sve veći broj istraživača posljednjih godina pokušava iskoristiti povoljne učinke bakra za razvoj novih biomedicinskih materijala za dobrobit ljudskog tijela.
U ovom završnom radu opisana su svojstva bakra te postupci njegovog dobivanja. Također su navedeni ekološki aspekti proizvodnje kao i utjecaj implantiranog bakra na zdravlje ljudi. Isto tako opisana su antimikrobna svojstva bakra u medicinskim implantatima, a na samom kraju navedena je sama upotreba i trajnost implantiranog bakra.Copper is an essential element found in the human body in microconcentration, and is necessary for the normal functioning of the human body. An increased or decreased concentration of copper in the body leads to various disorders that can consequently cause serious diseases and organ failure, and sometimes death. Copper is one of the most used metals that man uses in all spheres of his life. Due to the importance of the role of copper in the body, an increasing number of researchers have been trying to use the beneficial effects of copper in recent years to develop new biomedical materials for the benefit of the human body.
In this final paper, the properties of copper and the procedures for obtaining it are described. Environmental aspects of production as well as the impact of implanted copper on human health are also listed. The antimicrobial properties of copper in medical implants are also described, and at the very end, the use and durability of implanted copper is stated
Heavy metals as chemical hazards
No full textTeški metali su kemijski elementi koji imaju značajan utjecaj na zdravlje ljudi i okoliš zbog njihove toksičnosti i sposobnosti akumulacije. Izvori teških metala mogu biti prirodni i antropogeni, a teški metali se mogu podijeliti na esencijalne i neesencijalne. Toksičnost teških metala prvenstveno ovisi o njihovoj koncentraciji, ali i načinu djelovanja. U ovom radu istražuje se utjecaj teških metala, prvenstveno olova, kadmija, žive i arsena, ali i nekih drugih metala koji su prisutni u radnoj okolini. U ovom radu naglasak je stavljen na prisutnost teških metala u radnoj okolini, ali i na njihovo djelovanje i posljedice na ljudski organizam.Heavy metals are chemical elements that have a significant impact on human health and the environment due to their toxicity and ability to accumulate. Sources of heavy metals can be natural and anthropogenic, and heavy metals can be divided into essential and non-essential. The toxicity of heavy metals primarily depends on their concentration, but also on their mode of action. This paper examines the influence of heavy metals, primarily lead, cadmium, mercury and arsenic, but also some other metals that are present in the working environment. Emphasis is placed on the presence of heavy metals in the working environment, but also on their effects and consequences on the human body
Hazards of anthropogenic origin in the sea
No full textNapredak industrije, urbanizacija i intenzivno korištenje resursa imaju značajan utjecaj na kvalitetu morske vode. Iako je onečišćenje morske vode gorući problem čovječanstva ne pridaje mu se dovoljno važnosti. Samo onečišćenje najviše nastaje djelovanjem različitih industrija, ali ni utjecaj čovjeka ne možemo zanemariti. Ovaj rad istražuje različite izvore onečišćenja morske vode, identificirajući ključne uzroke i posljedice. Rad obuhvaća onečišćenja morske vode krutim i plastičnim otpadom, naftom, otpadnim vodama, balastnim vodama, radioaktivnim otpadom, kao i svjetlosno, zvučno, termalno i atmosfersko onečišćenje. Svaki od ovih izvora ima više potkategorija od kojih svaka ima specifične karakteristike onečišćenja te nam daje uvid u kompleksnu sliku onečišćenja morske vode. Cilj ovog rada je razumijevanje raznolikih izvora onečišćenja što je ključno za razvoj održivih strategija za zaštitu morskih ekosustava i osiguranje čiste morske vode za ljude i životinje. Daljnja istraživanja i primjena preventivnih mjera se trebaju usmjeriti na sprječavanje onečišćenja morske vode na samom izvoru kako bi se jednog dana riješio i taj problem.The progress of industry, urbanization, and intensive resource use have a significant impact on the quality of seawater. Although marine pollution is a pressing issue for humanity, it is not given sufficient importance. Pollution primarily arises from various industries, but the human impact cannot be overlooked. This paper explores different sources of marine pollution, identifying key causes and consequences. It encompasses pollution of seawater by solid and plastic waste, oil, wastewater, ballast water, radioactive waste, as well as light, sound, thermal, and atmospheric pollution. Each of these sources has multiple subcategories, each with specific pollution characteristics, providing insight into the complex picture of marine pollution. The aim of this paper is to understand the diverse sources of pollution, which is crucial for the development of sustainable strategies to protect marine ecosystems and ensure clean seawater for humans and animals. Further research and the implementation of preventive measures should focus on preventing marine pollution at the source to eventually resolve this issue
Measurement of the ambient dose rate equivalent H*(10)/t (devices and measurements)
No full textOdabrani diplomski rad na temu „Mjerenje brzine ambijentalnog doznog ekvivalenta H*(10)/t (uređaji i mjerenja)“ poseban naglasak stavlja na korištenje uređaja za mjerenje i na metodologiju samog mjerenja. Rad je podijeljen u dva dijela, teorijski dio i eksperimentalni dio koji sadrži studiju slučaja unutar koje su prikupljeni podaci mjerenja uz pomoć Polimaster uređaja za mjerenje ionizirajućeg zračenja analizirani, prezentirani i na temelju kojih je u konačnici provedena rasprava. Mjerenje je konkretno provedeno uz pomoć osobnog dozimetra za mjerenje zračenja, tip PM1605BT. Upravo ambijentalni dozni ekvivalent ima ključnu ulogu prilikom mjerenja procjene izloženosti ionizirajućem zračenju, a njegova brzina prikazana parametrom H*(10)/t predstavlja intenzitet zračenja tokom promatranog vremenskog razdoblja. Preciznost prilikom mjerenja navedenog parametra, ali i samo njegovo razumijevanje izuzetno je važan faktor u području zaštite od zračenja unutar industrijskih, zdravstvenih, ali i istraživačkih okruženja koja su objašnjena unutar poglavlja vezanog uz područja primjene ambijentalnog doznog ekvivalenta. Najvažniji dio rada je istraživački, odnosno eksperimentalni u kojem su odrađena mjerenja ambijentalnog doznog ekvivalenta na nekoliko lokacija na području grada Siska, u neposrednim blizinama različitih industrija čiji rezultati predstavljaju izazove i podlogu za donošenje rješenja u praksi. A sve navedeno u svrhu poboljšanja radiološke zaštite i sigurnosti zdravlja ljudi i okoliša u različitim područjima. Nakon izvršenih mjerenja i usporedbe dobivenih rezultata donosi se zaključak kako na području grada Siska ne postoji opasnost od zračenja te samim time nema potrebe za uspostavljanjem mjera zaštite od zračenja.The selected thesis titled "Measurement of the Ambient Dose Equivalent Rate H*(10)/t (Devices and Measurements)" emphasizes the use of measurement devices and the methodology of the measurement itself. The thesis consists of two parts the theoretical part, whose name suggests what it consists of, and the experimental part, which includes a case study in which the collected measurement data using the Polimaster ionizing radiation measurement device were analyzed, presented, and discussed. Measuring device used during the research is a personal dosimeter for radiation measuring, type PM1605BT. Ambient dose equivalent plays a crucial role in assessing exposure to ionizing radiation and its rate, represented by the parameter H*(10)/t, indicates the intensity of radiation over a given period. The precision in measuring this parameter and also understanding it is an extremely important factor in the field of radiation protection within industrial, healthcare, and research environments, which are explained in the chapter related to the applications of ambient dose equivalent. The most important part of the thesis is the research or experimental section in which measurements of the ambient dose equivalent were carried out at several locations in the city of Sisak, in the various industries nearby. The results of these measurements present challenges and provide a basis for practical solutions. All of this is aimed at improving radiological protection and ensuring human health, safety and the environment safety in various areas. After the measurements are done and after comparing of the results, the conclusion is that there is no danger of radiation in city Sisak area so there is no need to establish any radiation protection measurements
Development of a new alloying system for tool steels based on thermodynamic parameters
No full textU ovom istraživanju proučavana je termodinamika metalurških procesa naprednih metalnih alata, tj. alatnih čelika. Istraživanja su pokazala rezultate modeliranja kemijskog sastava dva tipa alatnih čelika za topli rad oznake Dievar i HTCS-130. Zabilježeno je izdvajanje pojedinih faza, nastanak karbida te su praćene temperaturne promjene i područja u kojima se odvijaju termodinamički procesi. Svi parametri povezani su s parametrima koji su dobiveni nakon elektrokemijskih ispitivanja, a metalografskom analizom utvrđene su nastale pojave u čelicima. Iz dobivenih rezultata nakon provedenih ispitivanja uslijedilo je uspoređivanje dvaju tipova čelika te je donesen zaključak o njihovim mogućnostima primjene u raznolikim uvjetima u kojima se alatni čelici primjenjuju.In this research, the thermodynamics of metallurgical processes of advanced metal tools, i.e. tool steels, was studied. Research has shown the results of modeling the chemical composition of two types of hot work tool steels, Dievar and HTCS-130. The separation of individual phases, the formation of carbides was recorded, and temperature changes and areas where thermodynamic processes take place were monitored. All parameters are related to the parameters obtained after electrochemical tests, and metallographic analysis determined the phenomena in the steels. From the results obtained after the tests, a comparison of the two types of steel followed, and a conclusion was reached about their application possibilities in the various conditions in which tool steels are used
Safety of operators of special interventions unit
No full textSigurnost obavljanja radnog zadatka svakog djelatnika od iznimne je važnosti, a provedbi sigurnog načina obavljanja radnog zadatka pomaže odrađena procjena rizika. U ovom završnom radu analizirala se sigurnost rada policijskog službenika specijalističkog tima interventne policije i provela procjena rizika za njegovo radno mjesto. Rad se sastoji od teorijskog i analitičkog dijela. U teorijskom dijelu opisan je način izrade procjene rizika, matrica po kojoj se procjena rizika provodi i načini tretiranja uočenog rizika. U analitičkom dijelu detaljnije su opisane opasnosti, štetnosti i napori s kojima se u svom radu susreću policijski službenici specijalističkog tima interventne policije. Nakon uočenih opasnosti provedena je procjena rizika te su potom predložene mjere koje se moraju provoditi kako bi se određeni rizik spriječio ili smanjio. Detaljnije je predstavljena zaštitna osnovna i specijalna policijska oprema, taktika postupanja, rad na siguran način s osnovama rukovanja oružjem u cilju sprječavanja nesreća na radu.The safety of performing the work task of each employee is extremely important, and the implementation of a safe way of performing the work task is helped by a risk assessment. In this final paper, the work safety of the police officer of the intervention police specialist team was analyzed and a risk assessment was carried out for his workplace. The paper consists of a theoretical and analytical part. The theoretical part describes the method of creating a risk assessment, the matrix by which the risk assessment is carried out and the ways of treating the perceived risk. In the analytical part, the dangers, harms and efforts faced by the police officers of the specialist intervention police team are described in more detail. After the perceived dangers, a risk assessment was carried out, and then measures were proposed that must be implemented in order to prevent or reduce a certain risk. Protective basic and special police equipment, handling tactics, working in a safe manner with the basics of handling weapons in order to prevent accidents at work are presented in more detail