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Measurement of illumination in the educational institutions
No full textU teorijskom dijelu završnog rada obrađena je tema svjetlosti te učinci svjetlosti na ljudski organizam, kao i kratki povijesni pregled istraživanja vezan za unutarnju rasvjetu. Obrađuju se osnovni faktori kvalitete unutarnjeg osvjetljenja, kao i osnove projektiranja unutarnje rasvjete te same rasvijetljenosti u školama. U eksperimentalnom dijelu rada provedena su mjerenja razine rasvijetljenosti u različitim prostorijama Industrijsko - obrtničke škole, kao što su: učionice, radionice, stubišta, kabineti te različite prostorije u okviru sportskih dvorana itd. Za mjerenje rasvijetljenosti korišten je univerzalni mjerni instrument Lutron LM, a mjerenja su provedena prema propisanim metodama i tehnikama, od strane stručne osobe. Dobivene vrijednosti uspoređene su s normiranim, zakonski propisanim vrijednostima prema normi HRN EN 12464-1:2021: Svjetlo i rasvjeta - Rasvjeta radnih mjesta - 1. dio: Unutrašnji radni prostori, čime je omogućena objektivna procjena kvalitete postojeće unutarnje rasvjete u školskim prostorima. Na temelju rezultata doneseni su zaključci o eventualnim odstupanjima od norme te mogućim poboljšanjima rasvjetnih uvjeta u svrhu unapređenja radnog i obrazovnog okruženja. Cilj rada je istaknuti važnost pravilnog planiranja i korištenja rasvjete u unutarnjim prostorima te prostorima obrazovnih ustanova kako bi se osigurala udobnost, sigurnost i učinkovitost korisnika.The theoretical part of the thesis deals with the topic of light, the effects of light on the human body and a brief historical overview of research in the field of interior lighting. The basic factors for the quality of interior lighting are discussed as well as the principles for the design of interior lighting and the lighting itself in schools. In the experimental part of the work, measurements of lighting levels were carried out in various rooms of the Industrial and Crafts School, such as classrooms, workshops, stairwells, cabinets and various rooms within the sports halls, etc. The Lutron LM universal measuring device was used to measure illuminance. The measurements were carried out by an expert according to the prescribed methods and techniques. The values obtained were compared with the standardized, legally prescribed values in accordance with the HRN EN 12464-1:2021 standard: Light and lighting - Lighting of workplaces - Part 1: Indoor workplaces, which provides an objective assessment of the quality of existing indoor lighting in school buildings. Based on the results, conclusions were drawn about possible deviations from the standard and possible improvements to lighting conditions in order to improve the working and educational environment. The aim of this work is to emphasise the importance of appropriate planning and use of lighting in indoor spaces and rooms of educational institutions to ensure the comfort, safety and efficiency of users
Effect of melt retention after treatment on the final quality of nodular cast iron HR GJS 400-15
No full textNodularni lijev HRN-EN-GJS-400-15 koristi se u automobilskoj industriji za izradu dijelova poput zupčanika, diferencijala i osovina zbog svoje visoke čvrstoće i dobre žilavosti.
Konstantnim rastom potražnje kupci postavljaju sve veće zahtjeve za kvalitetnijim proizvodima. Da bi proizvođači to ispunili, važno je konstantno kontrolirati kemijski sastav, minimalizirati eventualne greške u mikrostrukturi i modificirati postupke proizvodnje. U ovom završnom radu prati se proizvodnja odljevaka iz HRN-EN-GJS-400-15, točnije utjecaj vremena zadržavanja taline nakon obrade u loncu na konačnu kvalitetu nodularnog lijeva. U procesu proizvodnje odlivene su dvije Y probe na kojima su provedena ispitivanja. Provedena su ispitivanja kemijskog sastava, mehaničkih svojstava i strukture nodularnog lijeva. Usporedbom rezultata svojstava, na početku i kraju lijevanja, uočava se kako pri kraju lijevanja dolazi do smanjenja u mehaničkih svojstava. Analiza strukture ukazuje kako se radi o željeznom lijevu s pretežno feritnom osnovom. Prema kraju lijevanja postupno raste udio perlita.Ductile iron, or nodular cast iron, HRN-EN-GJS-400-15 is used in the automotive industry to make parts such as gears, differentials and axles due to its high strength and good toughness. Demands on quality are constantly growing, customers are setting higher and higher demands. In order for manufacturers to fulfill this, it is important to constantly control the chemical composition and minimize possible defects in the microstructure, and to modify production procedures in order to increase production and reduce costs. In this final paper, the production of ductile iron HRN-EN-GJS-400-15 is monitored, specifically the influence of the melt retention time in the casting ladle on the final quality of ductile iron. Two Y-shaped cast samples were cast in the production process. Chemical composition, mechanical properties and structure of nodular cast iron were tested. By comparing the results of the properties, at the beginning and end of casting, it is observed that near the end there is a drop in the mechanical properties. Analysis of the microstructure indicates that matrix of cast iron is predominantly ferrite base. Towards the end of the process, the proportion of pearlite gradually increases
Fire extinguishing tactic in correctional facilities
No full textOvaj rad istražuje taktiku gašenja požara u zgradama kaznenih institucija, s naglaskom na specifične izazove i zahtjeve koje takvi objekti postavljaju pred vatrogasne postrojbe. Zgrade kaznenih institucija imaju jedinstvenu arhitekturu i sigurnosne mjere koje dodatno kompliciraju vatrogasne intervencije. Analizirane su karakteristike požara u zatvorenim prostorima, uključujući načine na koje se požar može širiti i specifične rizike povezane s ovim tipom objekata. Razmatrane su različite strategije gašenja požara, od tradicionalnih metoda do upotrebe naprednih tehnologija poput termovizijskih kamera i automatskih sustava za gašenje.
Rad također naglašava važnost sigurnosnih protokola, uključujući pravilnu procjenu rizika prije ulaska u zatvoreni prostor. Identifikacija opasnosti i implementacija mjera predostrožnosti ključni su za smanjenje rizika za vatrogasce i zatvorenike. Procjena rizika obuhvaća analizu strukturalne stabilnosti zgrade, identifikaciju potencijalno opasnih materijala i procjenu uvjeta unutar prostora zahvaćenog požarom.
Posebna pažnja posvećena je komunikaciji i koordinaciji među vatrogasnim timovima i drugim službama. Učinkovita komunikacija i koordinacija ključni su za brzo donošenje odluka i uspješno upravljanje intervencijom. Korištenje naprednih komunikacijskih sustava omogućuje neprekidnu razmjenu informacija, što je od vitalne važnosti u dinamičnim i opasnim situacijama.
Evidentno da uspjeh intervencija u zgradama kaznenih institucija ovisi o detaljnoj procjeni rizika, učinkovitoj upotrebi naprednih tehnologija i jasnoj komunikaciji. Potrebna je kontinuirana obuka vatrogasaca kako bi se osigurala njihova spremnost za specifične uvjete ovih intervencija. Rad također naglašava potrebu za daljnjim istraživanjima i razvojem novih strategija koje će dodatno poboljšati taktiku gašenja požara, s ciljem osiguravanja sigurnosti zatvorenika, osoblja i vatrogasaca.This paper investigates firefighting tactics in prison buildings, focusing on the specific challenges and demands these structures impose on fire brigades. Prison buildings have unique architecture and security measures that further complicate firefighting operations. The study analyses the characteristics of fires in confined spaces, including how fires spread and the specific risks associated with these types of buildings. Various firefighting strategies are considered, from traditional methods to advanced technologies like thermal imaging cameras and automatic suppression systems.
The paper also highlights the importance of safety protocols, including proper risk assessment before entering confined spaces. Identifying hazards and implementing precautionary measures are crucial for reducing risks to firefighters and inmates. Risk assessment involves analysing the structural stability of the building, identifying potentially hazardous materials, and assessing conditions within the fire-affected area.
Special attention is given to communication and coordination among fire teams and other services. Effective communication and coordination are crucial for quick decision-making and successful management of interventions. The use of advanced communication systems ensures continuous information exchange, which is vital in dynamic and hazardous situations.
It is evident that the success of interventions in prison buildings depends on detailed risk assessment, effective use of advanced technologies, and clear communication. Continuous training of firefighters is necessary to ensure their readiness for the specific conditions of these interventions. The paper also emphasizes the need for further research and development of new strategies to improve firefighting tactics, with the aim of ensuring the safety of inmates, staff, and firefighters
Use of fire hoses in fire extinguishing and control of their technical properties
No full textU ovom diplomskom radu daje se uvid u to da su vatrogasne cijevi jedan od osnovnih i glavnih dijelova vatrogasne opreme koja u svakom trenutku mora biti sigurna i pouzdana za korištenje. Nadalje, navedena je podjela vatrogasnih cijevi i za koju namjenu se koriste. Korištenjem dostupne literature knjiga i časopisa, proizvođačevih uputa, tehničke dokumentacije, zakonskih odredbi i vlastitog iskustva u ovom radu prikazuje se kako se u jednoj profesionalnoj postrojbi koriste, održavaju i ispituju vatrogasne cijevi. Također se objašnjava i upravljanje cijevnim prugama koje nam pruža znanje o tome što se može očekivati od cijevi, što će se dogoditi ako cijevna pruga ide u visinu ili u duljinu te na koji način se mogu osigurati dovoljne količine vode za gašenje ako se u blizini nalazi vanjski izvor vode.
U eksperimentalnom dijelu rada provedene su vježbe kojima se pokazalo kako se koriste vatrogasne cijevi, kako se postavljaju cijevne pruge, kako se vatrogasne cijevi održavaju i ispituju te kako ih treba propisno skladištiti. Pravilnim korištenjem i vođenjem brige o vatrogasnim cijevima te nakon provedenih ispitivanja na njima možemo biti sigurni u to da će nas naše vatrogasne cijevi sigurno i pouzdano služiti na budućim vježbama i eventualnim intervencijama.In this thesis, an insight is given into the fact that fire hoses are one of the basic and main parts of firefighting equipment that must be safe and reliable to use at all times. Furthermore, the division of fire hoses and the purpose for which they are used is specified. Using the available literature from books and magazines, manufacturer's instructions, technical documentation, legal regulations and my own experience, this paper shows how fire hoses are used, maintained and tested in a professional unit. The management of pipelines is also explained, which provides us with knowledge about what can be expected from the pipeline, what will happen if the pipeline runs in height or in length, and how we can ensure sufficient quantities of water for extinguishing if we have an external water source nearby.
In the experimental part of the work, exercises were carried out that showed how to use fire hoses, how to lay pipe lines, how to maintain and test fire hoses, and how to properly store them. By properly using and taking care of fire hoses and after conducting tests on them, we can be sure that our fire hoses will serve us safely and reliably in future exercises and possible interventions
Hazards of radiation in non-destructive testing of metal materials using the radiographic method
No full textNerazorna metoda radiografije, koja se sve više koristi u industriji za ispitivanje metalnih materijala donosi brojne prednosti, ali istovremeno izlaže osoblje i radnu okolinu opasnosti od zračenja. Upravo zbog toga, sigurnost pri primjeni ove metode je iznimno važna tema. Cilj završnog rada je pružiti dublji uvid u opasnosti i rizike od zračenja pri ispitivanju metalnih materijala nerazornom metodom radiografije, kroz konkretni primjer ispitivanja metalne cijevi u tvrtki STSI d.o.o. Prikazane su i provedene mjere predostrožnosti koje treba poduzeti kako bi se osigurala sigurnost osoblja i radne okoline. Nepravilna primjena ili nedostatak sigurnosnih mjera mogu dovesti do ozbiljnih posljedica, uključujući ozračenje osoblja i štetne utjecaje na okolinu. Stoga, osiguranje sigurnosti tijekom ispitivanja metodom radiografije postaje ključno. Pravilna obuka osoblja o sigurnosnim postupcima i korištenju zaštitne opreme poput dozimetara provedena je u ovom radu pri ispitivanju nerazornom metodom radiografije. Važnost održavanja sigurnosnih standarda u radnom okruženju, uključujući označavanje radioloških područja, ograničavanje pristupa neautoriziranim osobama i pravilno odlaganje radioaktivnog otpada utvrđeno je u radu kroz ispitivanje metalne cijevi nerazornom metodom radiografije. U radu je naglašena važnost sigurnosti pri primjeni metode radiografije u industrijskom ispitivanju metalnih materijala. Uz sigurnost osoblja pri ispitivanju metodom radiografije provedeno je ispitivanje kvalitete zavara na metalnoj cijevi pri čemu je utvrđeno je da ne pokazuje nikakve nedostatke. Također su utvrđene potencijalne opasnosti od zračenja prije, za vrijeme i nakon provođenja radiografskih ispitivanja pri čemu je određena obavezna zaštitna oprema i postupci.The non-destructive method of radiography, which is increasingly being used in the industry for testing metallic materials, brings numerous advantages but at the same time exposes personnel and the working environment to radiation hazards. Due to this, safety in the application of this method is an extremely important topic. The aim of paper is to provide a deeper insight into the dangers and risks of radiation during the testing of metal materials using the non-destructive method of radiography, through a specific example of testing a metal pipe at STSI Ltd. The precautionary measures that need to be taken to ensure the safety of personnel and the working environment are presented and performed. Improper application or lack of safety measures can lead to serious consequences, including personnel irradiation and adverse effects on the environment. Therefore, ensuring safety during radiographic testing becomes crucial. Proper staff training on safety procedures and the use of protective equipment such as dosimeters was carried out in this paper during examination by the non-destructive method of radiography. The importance of maintain safety standards in the work environment, including the marking of radiological areas, restricting access to unauthorized individuals, and proper disposal of radioactive waste is established in the paper through the examination of a metal pipe by the non- destructive method of radiography. In the paper, the importance of safety in the application of radiographic methods in industrial testing of metallic materials is emphasized. In addition to the safety of the personnel during the examination by radiography, a test of the weld quality on the metal pipe was carried out. It was determined that it did not show any defects. Potential hazards from radiation before, during and after radiographic tests were also determined, where protective equipment and procedures are provided
Hazards, harmfulness and efforts at hte workplace of workers in the retail sale of cosmetics and toiletries
No full textOvaj završni rad bavi se analizom opasnosti, štetnosti i napora kojima su izloženi radnici zaposleni u trgovini na malo kozmetičkim i toaletnim proizvodima. Maloprodajni sektor, osobito u segmentu kozmetike, karakterizira izloženost različitim rizicima – od fizičkih i kemijskih štetnosti do psihosocijalnih opterećenja. Kroz rad se prikazuju najčešći izvori profesionalnih opasnosti kao što su dugotrajno stajanje, nepravilna ergonomija radnog mjesta, kontakt s kemikalijama prisutnima u kozmetičkim proizvodima te učestali stres i komunikacija s klijentima. Rad također obrađuje pravne aspekte zaštite na radu, kao i primjere dobre prakse u cilju unapređenja radnog okruženja. Na temelju analize stručne literature i postojećih radnih uvjeta, predložene su mjere za poboljšanje zaštite zdravlja i sigurnosti zaposlenih, s naglaskom na prevenciju štetnih utjecaja i promicanje ergonomskih i higijenskih standarda na radnom mjestu.This thesis analyzes the hazards, harmful effects, and efforts encountered by workers in the retail sector of cosmetic and toiletry products. The cosmetic retail environment exposes employees to various occupational risks – including physical and chemical hazards, as well as psychosocial challenges. The paper highlights common risk factors such as prolonged standing, improper workplace ergonomics, exposure to chemicals found in cosmetic products, and the stress associated with constant customer interaction. It also explores legal frameworks for occupational safety, as well as examples of best practices aimed at improving workplace conditions. Based on an analysis of professional literature and current working conditions, the paper presents recommendations to enhance employee health and safety, focusing on the prevention of harmful exposure and the promotion of ergonomic and hygienic standards in the workplace
Firefighting Tactis Using Drones
No full textUpotreba bespilotnih letjelica (dronova) u vatrogastvu postaje sve češća praksa u modernim sustavima civilne zaštite. Njihova primjena donosi brojne prednosti, osobito u fazama izviđanja, nadzora i taktičkog planiranja prilikom gašenja požara. Ovaj diplomski rad bavi se analizom taktičkih mogućnosti koje dronovi omogućuju prilikom požarnih intervencija, s naglaskom na njihove operativne prednosti, tehničke karakteristike i integraciju u postojeće vatrogasne protokole.
Dronovi omogućuju brz uvid u stanje na terenu bez izravnog izlaganja vatrogasaca riziku. Pomoću kamera visoke rezolucije, termovizijskih sustava i GPS praćenja, moguće je u stvarnom vremenu pratiti širenje požara, detektirati žarišta, identificirati ugrožene objekte i osobe, te usmjeravati vatrogasne snage na najkritičnija mjesta. Osim toga, dronovi se mogu koristiti i za dostavu lakšeg vatrogasnog materijala ili komunikaciju u područjima bez signala.
U praktičnom dijelu rada provedena je vježba u suradnji s Vatrogasnom zajednicom grada Siska, uključujući DVD Sela i DVD „Mladost“ Sisak, u kojoj je testirana upotreba drona tijekom simulacije požara na otvorenom prostoru. Dron je korišten za izviđanje terena, nadzor kretanja vatre te za navođenje vatrogasaca i vozila. Rezultati vježbe pokazali su značajno poboljšanje u brzini donošenja odluka i učinkovitosti gašenja požara, uz istovremeno smanjenje izloženosti vatrogasaca opasnim uvjetima.
Zaključno, integracija dronova u vatrogasne taktike ne predstavlja zamjenu za ljude, već dodatni alat koji unapređuje sigurnost i operativnost. Nastavak razvoja ove tehnologije te edukacija vatrogasnog osoblja u njenoj primjeni ključni su za daljnji napredak vatrogasnog sustava.The use of unmanned aerial vehicles (drones) in firefighting has become an increasingly common practice in modern civil protection systems. Their implementation brings numerous advantages, particularly in the stages of reconnaissance, monitoring, and tactical planning during fire suppression operations. This thesis explores the tactical possibilities enabled by drones in firefighting interventions, with an emphasis on their operational benefits, technical features, and integration into existing firefighting protocols.
Drones provide a rapid overview of the situation on the ground without exposing firefighters to direct risk. Through the use of high-resolution cameras, thermal imaging systems, and GPS tracking, it is possible to monitor fire spread in real time, detect hotspots, identify endangered objects and individuals, and direct firefighting forces to the most critical locations. Additionally, drones can be used to deliver lightweight firefighting materials or maintain communication in areas without signal coverage.
As part of the practical segment of this research, an exercise was conducted in cooperation with the Firefighting Association of the City of Sisak, including the volunteer fire brigades DVD Sela and DVD "Mladost" Sisak. The exercise tested the use of a drone during a simulated wildfire in an open area. The drone was utilized for terrain reconnaissance, fire movement monitoring, and guiding firefighters and vehicles. The results of the exercise showed a significant improvement in decision-making speed and firefighting efficiency, while simultaneously reducing firefighter exposure to hazardous conditions.
In conclusion, the integration of drones into firefighting tactics does not replace human personnel but serves as an additional tool that enhances safety and operational performance. Continued development of this technology and the education of firefighting personnel in its application are crucial for the further advancement of the firefighting system
Appearance of Lüders bands in niobium microalloyed steel
No full textPosljednjih godina provode se intenzivna istraživanja nehomogenih deformacija na početku plastičnog toka materijala tijekom hladne deformacije. Prethodna istraživanja pokazala su da postoji razlika u ponašanju mikrolegiranih čelika na početku plastičnog toka s obzirom da kod čelika s dodatkom mikrolegirajućega elementa niobija dolazi do pojave Lüdersovih linija, dok čelici istog osnovnog kemijskog sastava bez dodatka mikrolegirajućega elementa niobija ne pokazuju pojavu nehomogenih deformacija, odnosno pojavu Lüdersovih linija. U ovoj doktorskoj disertaciji provedena su istraživanja na niobijem mikrolegiranom čeliku s različitim dodacima mikrolegirajućega elementa niobija dobivenima u industrijskim i poluindustrijskim uvjetima te niskougljičnom čeliku bez dodatka mikrolegirajućega elementa niobija. Primjenom suvremenih metoda istraživanja termografije i digitalne korelacije slike, zapaženo je da su nehomogene deformacije povezane s pojavom Lüdersovih linija. Statičkim vlačnim ispitivanjem uz suvremene metode, termografiju i digitalnu korelaciju slike te metodama za mikrostrukturna ispitivanja, istražen je utjecaj mikrolegirajućega elementa niobija na pojavu i propagaciju Lüdersovih linija. U svrhu mikrostrukturnih ispitivanja prije i nakon određenog stupnja deformacije korištene su metalografija, pretražna elektronska mikroskopija uz EBSD analizu, transmisijska elektronska mikroskopija te analiza rendgenskom difrakcijom. Posebna pozornost u istraživanju posvećena je formiranju i propagaciji Lüdersovih linija na početku plastičnog toka niobijem mikrolegiranoga čelika tijekom hladne deformacije. U cilju utvrđivanja utjecaja mikrolegirajućega elementa niobija, početne mikrostrukture i brzine deformacije na pojavu i propagaciju Lüdersovih linija te lokalne iznose deformacije provedena su ispitivanja na čelicima različitog kemijskog sastava, početne mikrostrukture i brzine deformacije. S obzirom da je kod niobijem mikrolegiranih čelika prethodnim istraživanjima uočena prisutnost sitnih, deformacijom induciranih, niobijevih precipitata ovim istraživanjem istražen je njihov utjecaj zajedno s dislokacijama na formiranje i propagaciju Lüdersove linije u različitim pozicijama zone deformacije kako bi se utvrdio njihov mehanizam nastajanja. Istraživanja su pokazala da utjecajni faktori različitog sadržaja mikrolegirajućega elementa niobija, početna mikrostruktura i brzina deformacije imaju utjecaj na propagaciju Lüdersove linije. Međutim, brzina deformacije nema utjecaj na pojavu Lüdersove linije dok dodatak mikrolegirajućega elementa niobija, početna mikrostruktura te veličina i sastav niobijevih precipitata imaju utjecaj na pojavu Lüdersove linije. Sitni, deformacijom inducirani, niobijevi precipitati i gustoća dislokacija pokazali su se kao parametri koji imaju značajan utjecaj na nastajanje i propagaciju Lüdersove linije. Detaljno je, po prvi puta, postavljen mehanizam formiranja i propagacije Lüdersove linije kod niobijem mikrolegiranoga čelika. Na kraju su postavljeni jednostavni matematički modeli za opisivanje utjecajnih parametara na formiranje i propagaciju Lüdersove linije. Postavljenim matematičkim modelima moguće je predvidjeti ponašanje niobijem mikrolegiranoga čelika s obzirom na pojavu Lüdersove linije na početku plastičnog toka tijekom hladne deformacije.Intensive research into inhomogeneous deformations at the start of the plastic flow in cold deformation of different metal materials has been carried out during the last few years. Previous research has clearly shown that there are differences in deformation behaviour of microalloyed steels at the start of the plastic flow. Lüders bands appear only in low carbon steels with addition of microalloying element niobium while low carbon steels with the same basic chemical composition without niobium do not show inhomogeneous deformations, i.e. Lüders bands. This research was carried out on low carbon steels without niobium and niobium microalloyed steels with various additions of the microalloying element niobium obtained in industrial and semi-industrial conditions. Connection of Lüders bands with inhomogeneous deformations was observed using modern methods of thermography and digital image correlation. Influence of microalloying element niobium on Lüders bands formation and propagation was researched by static tensile tests with thermography and digital image correlation, and modern methods of microstructural testing. Metallography, scanning electron microscopy with EBSD analysis, transmission electron microscopy and X-ray diffraction analysis were used for the purpose of microstructural testing before and after a certain deformation degree. In this research particular attention was given to the formation and propagation of Lüders bands at the start of the plastic flow of niobium microalloyed steels during cold deformation. Tests were conducted on steels with various chemical composition, initial microstructure and strain rate in order to determine the influence of the microalloying element niobium, the initial microstructure and strain rate on the appearance and propagation of Lüders bands as well as local strain amounts. Previous studies have shown a presence of fine deformation induced niobium precipitates in niobium microalloyed steels. This doctoral thesis presents a research of their influence along with dislocations on the formation and propagation of Lüders bands in various positions of the deformation zone to determine the mechanism of Lüders bands formation. The research showed an influence of various contents of the microalloying element niobium, initial microstructure and strain rate on the propagation of the Lüders bands. However, the strain rate do not have influence on the appearance of Lüders bands while the addition of the microalloying element niobium, initial microstructure, size and chemical composition of niobium precipitates have influence on the appearance of Lüders bands. Fine deformation induced niobium precipitates and dislocation density showed a significant impact on the formation and propagation of Lüders bands. The mechanism of formation and propagation of Lüders bands in niobium microalloyed steel is set out in detail for the first time. Simple mathematical models for the parameters influencing the formation and propagation of Lüders bands were developed at the end of the doctoral thesis. Behaviour of niobium microalloyed steels with Lüders bands can be predicted by the defined mathematical models at the start of the plastic flow during the cold deformation
Certificiranje i sigurnost pri ispitivanju metalnih materijala kod nerazornih metoda
No full textIspitivanja materijala metodama bez razaranja (eng. Non-destructive testing - NDT) rade se s ciljem otkrivanja grešaka u materijalima, a da se pri tome ispitivani metalni materijali ne oštete. Osim utvrđivanja grešaka ovim metodama kod ispitivanja metalnih materijala, omogućeno je i određivanje svojstava grešaka kao što su veličina i oblik greške, te dubina na kojoj se greška nalazi. Obzirom na važnost ispitivanja metalnih materijala nerazornim metodama vrlo je važno da ovu vrstu ispitivanja provode certificirani djelatnici obzirom na kvalitetu provedenih ispitivanja te sigurnost osoblja koje provodi ispitivanja. U ovom završnom radu prikazan je postupak pripreme osoblja tvrtke STSI d.o.o. za postupak certifikacije u području nerazornih ispitivanja na primjeru ispitivanja magnetskom metodom. Ujedno je navedena i važnost korištenja zaštitne opreme i moguće opasnosti pri ispitivanju magnetskom metodom.Testing of materials using non-destructive methods (Non-destructive testing - NDT) is done with the aim of detecting defects in the materials, without damaging the tested metal materials. In addition to the determination of defects, these methods allow the determination of the properties of the defects, such as the size and shape of the defect, and the depth at which the defect is located during testing metal materials. Considering the importance of testing materials using non-destructive methods, it is very important that this type of testing is carried out by certified personnel, considering the quality of the tests carried out and the safety of personnel that performing testing. This paper presents the process of the staff preparing in STSI Ltd. for the certification procedure in the field of non-destructive testing on the example of testing with the magnetic method. The importance of using protective equipment and the possible dangers of testing with the magnetic method are mentioned as well
Applications of titanium alloys in biomedicine"
No full textTitan i njegove legure imaju veliku primjenu u biomedicinskoj industriji zahvaljujući njihovim izvanrednim svojstvima, kao što su biokompatibilnost, visoka čvrstoća, otpornost na koroziju i mala gustoća. Ova svojstva omogućavaju široku primjenu titana u raznim biomedicinskim disciplinama, i to u ortopediji i stomatologiji, mikro- i makrokirurgiji, kao i u proizvodnji kirurških instrumenata. Titan se naročito koristi u implantatima za zamjenu velikih zglobova, kao što su kukovi i koljena; u stomatološkim implantatima; i u kardiovaskularnim uređajima, kao što su koronarni stentovi i umjetni srčani zalisci. Titan osigurava stabilnost i dugovječnost ovih implantata, zahvaljujući oksidnom filmu na površini implantata te tako poboljšava kvalitetu života pacijenata koji su pretrpjeli operacije. Kirurški instrumenti izrađeni od titana također su popularni: jednako su izdržljivi, biokompatibilni i otporni na koroziju. Njihova upotreba u raznim vrstama operativnih zahvata omogućava smanjenje rizika od infekcija kod pacijenata i podiže efikasnost zahvata na nivo koji osigurava brzi povratak pacijenata u normalni život.Titanium and its alloys are widely used in the biomedical industry due to their outstanding properties such as biocompatibility, high strength, corrosion resistance and low density. Due to these properties, titanium is used in various biomedical disciplines such as orthopaedics and dentistry, microsurgery and macrosurgery, as well as in the manufacture of surgical instruments. Titanium is used in particular in implants for the replacement of large joints such as hips and knees, in dental implants and in cardiovascular devices such as coronary stents and artificial heart valves. Thanks to the oxide layer on the surface of the implant, titanium ensures the stability and longevity of these implants and thus improves the quality of life of patients undergoing surgery. Surgical instruments made of titanium are also very popular: they are just as durable, biocompatible and corrosion-resistant. Their use in various types of surgical procedures reduces the risk of infection for patients and increases the efficiency of the procedure to a level that allows patients to return to normal life quickly