Karlovac University of Applied science

Karlovac, Croatia

Karlovac University of Applied science

Karlovac, Croatia
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Macan J.,University of Zagreb | Brckovic L.,University of Zagreb | Brckovic L.,Karlovac University of Applied science | Gajovic A.,Ruder Boskovic Institute
Journal of the European Ceramic Society | Year: 2017

Influence of addition of alumina and preparation methods (sol-gel synthesis and mechanochemical preparation) on crystallization and morphology of yttria stabilised zirconia was examined. Presence of alumina was found to delay crystallization of zirconia, the effect being more pronounced at higher alumina content. The two oxides form easily distinguished separate phases. Milling lowers the crystallization temperatures of the sol-gel derived powders since nuclei are formed during the milling and smaller particle size allows easier removal of residual organic components. The milling results in crystallization of some monoclinic zirconia, both in sol-gel derived powders and in case of mechanochemical processing. There are no significant differences between the preparation methods in pore size and relative density of sintered tablets: powders obtained by mechanochemical processing and milled sol-gel derived powders both give tablets with homogeneous morphology. The advantage of sol-gel process is preparation of pure tetragonal zirconia phase without traces of monoclinic phase. © 2017 Elsevier Ltd.

Jankovic A.,General Hospital Karlovac andrije Stampara 3 | Korac Z.,General Hospital Karlovac andrije Stampara 3 | Bozic N.-B.,General Hospital Karlovac andrije Stampara 3 | Stedul I.,Karlovac University of Applied science
Injury | Year: 2013

We evaluated the incidence and aetiology of anterior knee pain (AKP) in a series of patients that underwent intramedullary nailing for stabilisation of tibial fractures. During the preparation of the entry site no excision of the infrapatellar fat was allowed and electrical haemostasis was kept at the lowest level. Medullary canal was reamed and the nails inserted in position of knee flexion over 100 degrees. All fractures were fixed using medial paratendinous approach. Functional outcome was measured using Lysholm knee score. The knee range of movement and return to previous level of activity were also documented and analysed. Mean follow up was 38.9 months (range 12-84 months). In total 60 patients with 62 tibial shaft fractures were analysed. The mean age at the time of final follow up was 49.4 years (range 20-87). In 22 (35.5%) a newly developed and persisting pain in the anterior region of the operated knee was reported. According to VAP scale, the pain was mild (VAS 1-3) in 12 cases (19.4%) and moderate (VAS 4-6) in 10 (16.1%). In 16 cases (73%) the pain was noticed 6-12 months after injury and subjectively related to return to full range of working and recreational activities. The mean Lysholm knee score in the group without AKP was 90.8. In the AKP group with mild pain it was 88.4 and in the group with moderate AKP it was 79.9. Complete return to previous professional and recreational activities occurred in 49/60 patients (81.7%). Content with the treatment regarding expectations in recovery dynamics and return to desired level of activity was present in 98.3% of patients; one patient was unsatisfied with the treatment. Our results indicate that respecting the physiological motion of Hoffa pad and menisci during knee flexion, accompanied with atraumatic mobilisation of retrotendinous fat, reduces incidence and severity of anterior knee pain following intramedullary fixation of tibial shaft fractures. © 2013 Elsevier Ltd.

Vrsnak B.,University of Zagreb | Zic T.,University of Zagreb | Vrbanec D.,University of Zagreb | Temmer M.,University of Graz | And 9 more authors.
Solar Physics | Year: 2013

We present the "Drag-Based Model" (DBM) of heliospheric propagation of interplanetary coronal mass ejections (ICMEs). The DBM is based on the hypothesis that the driving Lorentz force, which launches a CME, ceases in the upper corona and that beyond a certain distance the dynamics becomes governed solely by the interaction of the ICME and the ambient solar wind. In particular, we consider the option where the drag acceleration has a quadratic dependence on the ICME relative speed, which is expected in a collisionless environment, where the drag is caused primarily by emission of magnetohydrodynamic (MHD) waves. In this paper we present the simplest version of DBM, where the equation of motion can be solved analytically, providing explicit solutions for the Sun-Earth ICME transit time and impact speed. This offers easy handling and straightforward application to real-time space-weather forecasting. Beside presenting the model itself, we perform an analysis of DBM performances, applying a statistical and case-study approach, which provides insight into the advantages and drawbacks of DBM. Finally, we present a public, DBM-based, online forecast tool. © 2012 Springer Science+Business Media B.V.

Medic S.,Karlovac University of Applied science | Kondic Z.,Varazdin University of Applied science | Runje B.,University of Zagreb
Tehnicki Vjesnik | Year: 2012

The Laboratory for Precise Measurement of Length, which is at the same time the Croatian National Laboratory for Length (in text Laboratory) takes part in CIPMMRA(Comité International des Poids et Mesures, Mutual Recognition Arrangement) comparisons of length standards, which include line scales as very important standards of length.When the results reported in the comparisons, it is necessary to state the estimated measurement uncertainty. Recently, the Monte Carlo simulations (MCS) have been increasingly applied in the field of estimation measurement uncertainties. The paper presents validation of the realised measurement uncertainty by GUM method in process of precise line scales calibration using the MCS method. The MCS method is based on random number generation from the probability density functions for each input value and forming of experimental probability density function of the output value. Also, the paper presents obtained results of the international comparison measurement which representing a real validation of the device and evaluated measurement uncertainty.

Horvat D.,University of Zagreb | Ilijic S.,University of Zagreb | Kirin A.,Karlovac University of Applied science | Narancic Z.,University of Zagreb
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2015

Within the framework of the extended teleparallel gravity, a new class of boson stars has recently been constructed by introducing the nonminimal coupling of the scalar field to the torsion scalar. An interesting feature of these static, spherical, self-gravitating configurations of the massive complex scalar field is their central region with outwardly increasing energy density, surrounded by a thick shell within which the joining with the usual asymptotically Schwarzschild tail takes place. In this work we extend the original model with the U(1) gauge field and we find that the combined effect of the charge and coupling of the field to torsion leads to a significant increase of the maximal mass and the particle number that can be supported against gravity. We also show that some charged configurations preserve the property of having the outwardly increasing energy density over the central region, regardless of the fact that charging the configurations affects the anisotropy of the pressures in the opposite way relative to that of the field-to-torsion coupling terms. © 2015 American Physical Society.

Vyroubal D.,Karlovac University of Applied science | Lackovic I.,University of Zagreb
SAS 2015 - 2015 IEEE Sensors Applications Symposium, Proceedings | Year: 2015

Target temperature effect on eddy current displacement sensing is analyzed and evaluated by simulation. The equivalent target quality factor is detected as the main factor that, along with the probe equivalent quality factor, determines this effect. It manifests in ambiguity of displacement measurement, as well as, masking the displacement variation by target temperature variation, and vice versa. The analysis and the simulation show that there is an optimal operating frequency for minimum sensitivity over an acceptable displacement range. © 2015 IEEE.

Kirin S.,Karlovac University of Applied science | Dragcevic Z.,University of Zagreb | Rogale S.F.,University of Zagreb
Tekstil | Year: 2014

In the real manufacturing process the technological operation of sewing trousers side seams was recorded using a video system. Using modern methods of industrial engineering the structure of technological operation, workload (OADM) and share of unsuitable working postures (OWAS) were determined. It was found that at the existing workplace the unfavorable relationship of man-machine-environment leads to a high degree of workload caused by the forced position of spine and head, increased abdominal pressure, and reduction in visual skills and motor skills. Using the ERGOPlan software a redesign of the existing workplace was performed, and according to the anthropometric proportions of workers seating height, height of the machine work surface, working methods were determined, and using the method of predetermined times (MTM) the optimal working method with associated time norms was determined. Dynamic and static simulation of performing the technological operation at the redesigned workplace shows that the work is done in an economically favorable posture with considerably reducing workload, which results in increasing workplace productivity while reducing fatigue.

Mihalic T.,University of Zagreb | Medic S.,Karlovac University of Applied science | Kondic Z.,Varazdin University of Applied science
Tehnicki Vjesnik | Year: 2013

The improvements of the characteristics of centrifugal pump were investigated in this work experimentally and with computational fluid dynamics (CFD) analysis of the influence of adding vortex rotor to centrifugal one. The idea behind that improvement is in creating the so-called coherent structures of eddies and turbulence in the peripheral area of the vortex rotor mounted at the back side of centrifugal rotor. Research on the energy transformations in the centrifugal vortex pump in this work was carried out using control volume method for simulations of the flow in the centrifugal and the centrifugal vortex pump, and also by taking measurements of relevant parameters that describe the performance of pumps at their physical models. The measurement results were used as experimental validation and verification of numerical simulations; in contrast, flow visualization derived from the numerical simulation was used to interpret measurements. In deriving that experimental procedure, special care was taken with the flow measurements. The reason for this is in the fact that the flow measurements had the biggest influence on the overall measurement uncertainty. However, flow measurements were the most demanding with regard to experiment design and in taking the measurement readings. This experimental - CFD research made it possible to undertake an assessment of vortex rotor contribution on the head of centrifugal vortex pump. The influence of the vortex rotor on the efficiency of the centrifugal vortex pump was studied in contrast to the efficiency of a centrifugal pump with the same geometry. An analysis of the structure of flow was conducted in order to better understand the energy transformations that are the result of interaction between vortex rotor and the flow from the channels of centrifugal part of centrifugal vortex rotor.

Kalinski I.,University of Zagreb | Juretic D.,University of Zagreb | Kusic H.,University of Zagreb | Peternel I.,Karlovac University of Applied science | Bozic A.L.,University of Zagreb
Journal of Photochemistry and Photobiology A: Chemistry | Year: 2014

The influence of structure of sulfoaromatics (SulfoArs) on photooxidative treatment by UV/H2O2 process was investigated. In that purpose, benzenesulfonic acids with different substituents in para position (H, OH, CH3, Cl, NH2) were chosen as representatives of SulfoArs water pollutants. The effects of operational parameters of UV/H 2O2 process and structural features of SulfoArs on their degradation kinetics were investigated by statistical/empirical approach employing the design of experiments and response surface methodology. Different optimal conditions yielding maximal degradation rates were established. The observed degradation rate constants and reaction rate constants of SulfoArs with hydroxyl radicals follow the different decreasing orders indicating the competitive kinetics with by-products formed through the structurally influenced degradation pathways. The mineralization kinetics is correlated with the degradation pathways of studied SulfoArs, the shared sequence within, and the influence of inorganic ions present in the reaction mixture upon the elimination of parent substituents. It was determined that the changes of biodegradability and toxicity toward Vibrio fischeri during UV/H2O2 treatment are related to the preferable degradation route including the elimination of parent substituent and subsequent hydroxylation. In the observed treatment period biodegradability was significantly improved in all cases, while the toxicity levels were higher than those of parent pollutants. © 2014 Elsevier B.V.

Lui L.,Karlovac University of Applied science | Molnar L.,Karlovac University of Applied science
Studies in Health Technology and Informatics | Year: 2016

Internet technologies and services impose global information standards in the sphere of healthcare as a whole, which are then implied and applied in the domain of cytology laboratories. Web-based operations form a significant operating segment of any contemporary cytology laboratory as they enable operations by the use of technology, which is usually free of the restrictions imposed by the traditional way of business (geographic area and narrow localisation of activities). In their operations, almost all healthcare organisations currently create and use electronic data anddocuments , which can originate both inside and outside the organisation. An enormous amount of information thus used and exchanged may be processed timely and in a high-quality way only by integrated information systems, given three basic safety requirements: data confidentiality, integrity and availability. In the Republic of Croatia, integration of private and public healthcare information systems has been ongoing for several years but the private healthcare does not yet operate as an integrated system. Instead, each office operates using its own separate information system, i.e. database. This paper elaborates the argument that the sample private cytology laboratory possesses an IT system that meets current market and stakeholder needs of the healthcare sector in Croatia, given that private doctors' offices/polyclinics use IT technologies in their operations but make only partial use of Internet capacities in the segment of communication with their business associates and patients, implying the need to continue the research on a statistically relevant sample of EU countries. © 2016 The authors and IOS Press.

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