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Papers by Suzana Jakovljević

Construction and Building Materials

BHM Berg- und Hüttenmännische Monatshefte

Tehnicki vjesnik - Technical Gazette, 2021

PVD coatings on hard materials reduce adhesion and abrasion wear, while some types of coatings al... more PVD coatings on hard materials reduce adhesion and abrasion wear, while some types of coatings also reduce friction. The temperature of the PVD process is lower than the tempering temperature of steels, so there is no deformed parts and no input of new stresses. During the heat treatment, the PVD process is performed at the end because the PVD coating does not require any subsequent heat treatment. This paper investigates the effect of applying PVD coatings (cVIc and nACVIc) on adhesiveness to three quenched and tempered structural steels (45S20, C45E and 42CrMo4). Prior to coating, all steels were heat-treated within the process of normalization, quenching and tempering, and were treated to four different surface roughnesses. Results obtained by measuring adhesiveness are statistically analyzed. Based on the experimental tests, it is determined that the adhesiveness of applied PVD coatings to quenched and tempered steels depends more on the type of coating and on previous heat treatment of the steel, and less on the type of steel and initial roughness.

Smjestaj propulzijskog sustava i utjecaj forme broda na njihov smjestaj prikazan je na patrolnim ... more Smjestaj propulzijskog sustava i utjecaj forme broda na njihov smjestaj prikazan je na patrolnim brodovima. Patrolni brodovi koji su uzeti kao reprezentantni brodovi su brodovi poludeplasmanske forme iz serije SKLAD i predviđeni su za plovidbu u Jadranskom akvatoriju. Reprezentantni brodovi dobiveni su programom SKLAD, na osnovu predhodno definiranih brzina i doplova uz određena ogranicenja. Programom WAG, za svaki reprezentantni brod, određena je geometrija brodskog vijka i potrebna snaga motora. Za reprezentantne brodove odabran je pogon dizelskim motorima, a za propulzore brodski vijci s krilima fiksnog uspona i mlazni propulzori. Svaki motor pogoni jedan propulzor: u slucaju brodskog vijka razmatrani su dva, tri ili cetiri vijka, a u slucaju mlazne propulzije dva propulzora. Forma broda uvjetovat ce položaj propulzijskog sustava visevijcanog broda i smjestaj strojarnica na brodu, a kod mlazne propulzije naglasit ce se na koje se karakteristike narocito mora vodititi racuna pri p...

Coatings

Tribological coatings are found on machine elements (e [...]

In this paper, a degradation of the photopolymeric material (PhPM), used as printing plate in the... more In this paper, a degradation of the photopolymeric material (PhPM), used as printing plate in the flexography reproduction technique, caused by accelerated aging has been observed. Since the basis process for production of printing plates from the PhPM is a radical cross-linking process caused by exposing to UV wavelengths, the assumption was that improper storage or irregular handling of the PhPM plate can change the surface and structure characteristics of the plates. Results have shown that the aging process causes degradation in the structure and changes in the surface of the PhPM printing plate.

Engineering review, 2017

This study presents the results of investigating the cause of contamination of aluminum oxide cer... more This study presents the results of investigating the cause of contamination of aluminum oxide ceramics (Al2O3) in the form of brown colored stain. Contaminated ceramic surfaces were examined with the scanning electron microscope (SEM) equipped with the Energy Dispersive Spectrometer (EDS). The results show the existence of the carbon in contaminated surface that does not exist in the basic raw materials composition, not even in traces. To determine the place and source of contamination, the investigations of the production process were carried out by stages. It was found that the semifinished product occurs in contact with carbon at two stages in the manufacturing process; by sintering semi-finished product on carbon plates and cooling with emulsion that contains carbon in traces during cutting. It was shown that contamination occurs in contact with alumina ceramics sintered on carbon plates.

Erozija cesticama je gubitak materijala s povrsine krutog tijela zbog relativnog gibanja (strujan... more Erozija cesticama je gubitak materijala s povrsine krutog tijela zbog relativnog gibanja (strujanja) fluida u kojem se nalaze krute cestice. Erozija kod koje je strujanje pod malim kutom u odnosu na povrsinu (manjim od 30°) naziva se abrazivna erozija, a kad cestice udaraju o povrsinu gotovo okomito (60° do 90°) to je udarna erozija. Jedna od prednosti nodularnog lijeva u odnosu na druge ljevove je njegova dobra otpornost na trosenje. Ipak treba imati na umu da ta otpornost ovisi i o uvjetima trosenja. Kad se govori o otpornosti na erozijsko trosenje krutim cesticama, ta otpornost znacajno ovisi o kutu udara cestica. U ovom radu ispitivana je otpornost na erozijsko trosenje pri dva kuta upada cestica (15 i 90°) te dvije velicine celicnih kuglica.

This paper reports the structural and electrochemical behaviour of (Ti(C, N)) and titanium dibori... more This paper reports the structural and electrochemical behaviour of (Ti(C, N)) and titanium diboride (TiB2) coatings prepared by PA CVD- Plasma Asisted Chemical Vapour Depositon process. Ttitanium carbonitride and titanium diboride are widely used as reinforcing materials in applications demanding high corrosion and wear resistance. The microstructure of both layers consists of primary titanium particles surrounded by a eutectic matrix, containing ferrite, eutectic boride, and titanium carbonitrides. The electrochemical characterisation was performed using electrochemical methods for analysing corrosion surface ; surface morphology was characterised by using a high-resolution scanning electron microscope (SEM). The results showed a susceptible to pitting corrosion and increased corrosion rate in 3.5% NaCl solution.

Biomaterials for orthopaedic applications have moved from materials available for different indus... more Biomaterials for orthopaedic applications have moved from materials available for different industrial applications into the development of materials with abilities to interact with the biological environment in the last 60 years. The choice of material used for designing a medical implant is governed by biocompatibility, bioadhesion, biofunctionality, mechanical properties, corrosion resistance, etc. Three categories of materials are presently used in prosthetic devices: metals, polymers and ceramics. Many engineering components can be improved with a coating (surface engineering). Coatings are applied to orthopedic components and other medical devices for a variety of reasons. For the long term success of cementless implants is crucial bone ingrowth around and with the porous surfaces. A variety of roughened surfaces and three-dimensional (3-D) porous surfaces have been used to enhance biological fixation on orthopedic implants for over 30 years. The porous coatings can take vario...

U radu su opisana dva postupka nanosenja slojeva prevlake. Prvi sloj Al2O3 nanesen je postupkom p... more U radu su opisana dva postupka nanosenja slojeva prevlake. Prvi sloj Al2O3 nanesen je postupkom plazma nastrcavanja na nehrđajuci celik (EN X22CrMoV121). Nakon njega je nanesen sloj ZrO2 postupkom sol-gel, uranjanjem. Parametri koji su se mijenjali pri sol-gel postupku su: temperatura toplinske obradbe ZrO2 sloja (400oC, 700oC, 1000oC) i broj uranjanja u otopinu kod temperature 700oC (ponavljan 4 i 8 puta), kako bi se vidio njihov utjecaj na svojstva prevlake. Na prevlakama je provedena materijalografska analiza ispitivanih ZrO2 prevlaka, te je izmjerena debljina, tvrdoca i modul elasticnosti. Ispitivana je otpornost na brazdanje prevlaka, otpornost na abraziju te definiran koeficijent trenja metodom "Ball on disc". Rezultati provedenih laboratorijskih ispitivanja pokazali su da razlicite temperature toplinske obradbe, kojoj se podvrgavaju uzorci prevlaka nakon geliranja i susenja i broj slojeva ZrO2, utjecu na cjelovitost prevlake kao i na mehanicka svojstva prevlaka. Nan...

Zbornik sažetaka Međunarodnog savjetovanja MATRIB 2012 održanog u Veloj Luci id 20. do 22.06.2012.

We study synergies between three promising methods to measure 2 < z < 5 largescale structure in t... more We study synergies between three promising methods to measure 2 < z < 5 largescale structure in the next decade. Optical spectroscopic surveys are the most mature, but become increasingly difficult at z > 2 and suffer from interloper problems even for spectroscopic surveys. Intensity mapping of the 21-cm signal can cover large volumes with exquisite fidelity, but is limited both by loss of information to foreground cleaning and by lack of knowledge of the mean signal. Cosmic microwave background (CMB) lensing is theoretically very clean, but ultimately measures just the projected variations in density. We find that cross-correlation between optical and radio can significantly improve the measurement of growth rate. Combining these with the CMB provides a promising avenue to detecting modified gravity at high redshifts, in particular by independently probing the Weyl and Newtonian potentials and by strengthening control of systematics. We find that cross-correlating a Stage ii 21-cm survey with DESI quasars with a reasonable brightness temperature prior could enable measurements of the growth rate f σ 8 at sub 3% and sub 8% levels at z = 3, 4, representing a factor of 4 and 8 improvement over constraints obtainable from DESI quasars alone. Similarly, cross-correlating 21-cm data with a futuristic LBG survey to m U V < 24.5 over 1000 square degrees will make possible f σ 8 measurements at close to 1% at z = 3 and 3% at z = 4, and improve similar constraints at z = 5 by close to a factor of 3 to sub-10% precision. Combining the above with CMB lensing from a Stage 4 CMB survey and LSST data can additionally constrain the gravitational slip γ parameter to similar precision at these redshifts, enabling us to test the predictions of general relativity at large scales.

Zbornik sažetaka međunarodnog savjetovanja MATRIB 2013, Vela Luka, 27.-29.06.2013

Acta Stomatologica Croatica, 2019

Usporedba posmične čvrstoće veze ortodontskih bravica lijepljenih na cirkonijeve i litijeve disil... more Usporedba posmične čvrstoće veze ortodontskih bravica lijepljenih na cirkonijeve i litijeve disilikatne krunice Uvod Uvođenjem inovativnih potpuno keramičkih materijala, nemetalni materijali koji se koriste u dentalnim restauracijama već dugo su predmet najnovijih istraživanja (1). I sve veći zahtjevi za estetikom lica povećali su potrebu za time, pa se sve veći broj odraslih pacijenata odlučuje za ortodontsku terapiju (2). Inače, ortodontske bravice dosta se loše lijepe na keramičke površine, osim ako njihova površinska karakteristika nije promijenjena određenim postupcima prije lijepljenja (3). Dosadašnja istraživanja pokazala su da je čvrstoća vezivanja bravica na različitim restauracijama povezana s mnogobrojnim čimbenicima, kao što su vrsta restaurativnog materijala i način hrapavljenja površine, materijal i oblik bravice, svojstva ljepila i svjetlosno polimerizirajuće svjetiljke. Kombinacija tih i drugih čimbenika može biti vrlo važna za uspješnost terapije (4-6).