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Reactive sintering of $MnZn$ ferrites
Tomaž Kosmač, Mihael Drofenik, 2001, izvirni znanstveni članek

Opis: Reaction-formed $MnZn$ ferrite was prepared and the decrease in shrinkage after sintering due to the volume expansion accompanying iron oxidation was studied. Green compacts consisting of the milled raw oxides $Fe_2O_3$, $Mn_3O_4$, $ZnO$ and metallic iron powder were sintered at 1350 °C in air. During the first hold at 800 °C, $Fe$ was oxidized to $\alpha-Fe_2O_3$ and $Zn$ ferrite was formed. Above 1300 °C the reaction bonding was completed and $MnZn$ ferrite, exhibiting a relatively low shrinkage, was formed. The chemical reactions involved during reaction bonding were associated with a volume expansion and porosity formation, compensating for the shrinkage on sintering. Intensive milling decreases the porosity after sintering but induces the oxidation of iron, and partially removes the shrinkage compensation caused by the presence of metallic iron.
Ključne besede: reaction-forming, $MnZn$ ferrite, inorganic technology, ferrite ceramics, reaction bonded ceramics, sintering, iron oxides, iron
Objavljeno: 25.08.2017; Ogledov: 274; Prenosov: 36
.pdf Celotno besedilo (441,54 KB)
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Nanocomposite foams from iron oxide stabilized dicyclopentadiene high internal phase emulsions
Sebastijan Kovačič, Christian Slugovc, Gregor Ferk, Nadejda B. Matsko, 2014, strokovni članek

Opis: Nanocomposite polyHIPE foams with open-cellular morphology were obtained using nanoparticles ($γFe_2O_3/Fe_3O_4$), surfactant (Pluronic L121) or nanoparticle/surfactant stabilized dicyclopentadiene high internal phase emulsions (DCPD HIPEs). Upon curing, cavity sizes were found to vary drastically between 950 ± 360 µm down to 7 ±3 µm de- pending on the HIPE formulations. As-obtained nanocomposite polyHIPE foams were functionalized using elemental bromine in THF. Upon bromination the nanoparticles are moved from the cavities surfaces into the bulk phase of the polymer scaffold, which affects the inductive-heating capability of the magnetic nanocomposite foams decreasing it by the factor of 2.
Ključne besede: chemical technology, nanocomposites, bromination, microstructure, pickering HIPEs, $γFe_2O_3/Fe_3O_4$ nanoparticles, Ring Opening Metathesis Polymerization (ROMP), dicyclopentadiene, inductive heating
Objavljeno: 24.08.2017; Ogledov: 287; Prenosov: 49
.pdf Celotno besedilo (967,87 KB)
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Measuring public procurement for innovation on the country level and the role of ICT support
Kristina Detelj, Tanja Markovič-Hribernik, Igor Pihir, 2015, izvirni znanstveni članek

Opis: Using of public procurement as a tool for promoting innovations has captured interest of many researchers in recent years. However, most of the research is focused on the impact of public procurement on the company's innovativeness. The article discusses the findings of the literature on this topic and proposes a model on how to transfer the concept from the company level to the level of the whole country. One of the biggest problems is unavailability of appropriate measures of this phenomenon, so the authors suggest that the concept of Public procurement for innovation can be approximated by participation of criterion of the most economically advantageous tender (MEAT). Implementation of this criterion in choosing the best offer can be supported and facilitated by using of ICT which can improve the efficiency of procurement process and enable more innovations.
Ključne besede: public procurement, innovation, most economically advantageous tender, MEAT, information and communication technology
Objavljeno: 03.08.2017; Ogledov: 232; Prenosov: 33
.pdf Celotno besedilo (868,61 KB)
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Multiple-effect evaporation in aluminosilicate technology
Dušan Klinar, Janvit Golob, 2001, strokovni članek

Opis: The article presents an engineering approach to the development of an alternative production with the existing equipment. Zeolite production is becoming an alternative to the old »Bayer« process for aluminum hydrate production. By applying appropriate know-how old equipment was used for an economically as well as ecologically acceptable production. In this equipment adaptation among other production steps the multistage evaporation battery was the most critical part of the process. We applied semi empirical approach on the basis of Z. Rant ideas to find heat transfer coefficients and to determine which equipment elements are more relevant for efficient performance and need serious maintenance.
Ključne besede: chemical engineering, evaporation in silicate technology, bauxite alumina production, evaporators, process optimization, heat transfer, heat flow, empirical equations, heat transfer coefficients, zeolites
Objavljeno: 24.08.2017; Ogledov: 384; Prenosov: 47
.pdf Celotno besedilo (354,14 KB)
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A Psychological Analysis of a Post Modern Adaptation of The Tempest
Deja Kučer, 2017, magistrsko delo

Opis: The master’s thesis A Psychological Analysis of a Post Modern Adaptation of The Tempest deals with scientific analysis of the underlying themes which are common to the play The Tempest (1610–11) from Elizabethan era and its modern adaptation, a science fiction film Forbidden Planet (1956). I focus on character analysis and continue with Freud’s psychological theory focusing on two models of human psyche, in which according to the structural model the psyche consists of three entities: id, ego and superego. The other model of the human psyche is the topographical model, where I explain the differences between the unconscious and conscious mind. I also present Freud’s theory of dreams. In addition, I link Freud’s theory to the two literary works. The analysis shows what consequences can occur if one’s id, as a source of aggressive drives, gets too strong and acts only to satisfy its primeval impulses. Through parallelism between magic and technology I found that technology has the greatest impact on the one who possess it.
Ključne besede: The Tempest, Forbidden Planet, adaptation, Freud, id, dreams, magic, technology
Objavljeno: 07.03.2017; Ogledov: 483; Prenosov: 76
.pdf Celotno besedilo (1,08 MB)

Influence of the working technology on the development of alloys H13-w(Cu) 87.5 %
Uroš Artiček, Marko Bojinović, Mihael Brunčko, Ivan Anžel, 2014, izvirni znanstveni članek

Opis: Most dies in the casting industry for injection moulding are machined from the premium-grade H13 tool steel. They provide excellent performance in terms of mechanical properties and service life; however, these dies are characterised by a relatively low thermal conductivity. The tool-and-die industry is interested in depositing a material of a high thermal conductivity onto steel in order to improve the thermal management and productivity. We have explored the possibility of using copper with a new technology. In this study, the microstructure evolution and mechanical properties are discussed using the Laser Engineered Net ShapingTM (LENSTM) technology. For a better understanding of the solidification, the microstructure of a LENS sample was compared with the microstructure of a reference alloy produced with the ingot-casting technology having the same chemical composition of H13-w(Cu) 87.5 %. We carried out light microscopy, scanning electron microscopy, an EDS microchemical analysis, the tensile test and microhardness testing. The results show a successful fabrication of LENS samples; their microstructure is more homogeneous compared to the castings; they show better mechanical properties and represent a good potential for further development and use.
Ključne besede: casting, laser engineered net shaping technology, microstructure, mechanical properties
Objavljeno: 16.03.2017; Ogledov: 436; Prenosov: 62
.pdf Celotno besedilo (3,28 MB)
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Processing poly(ether etherketone) an a 3D printer for thermoplastic modelling
Bogdan Valentan, Žiga Kadivnik, Tomaž Brajlih, Andy Anderson, Igor Drstvenšek, 2013, izvirni znanstveni članek

Opis: PEEK, poly(ether etherketone), is one of the high-quality industrial polymers. It is widely used in extremely demanding areas like automotive, aircraft and space industries. Because of the fact that it is bio-compatible, PEEK is also used for medical implants that are usually made by milling a block of the material. The article presents the results of an investigation of processing PEEK on a 3D printer for thermoplastic modelling. The used procedure is one of the additive manufacturing procedures and, as such, it builds a product by adding material layer by layer to get the finished product. Commercially available machines are unable to achieve the required melting and environment temperatures, so a new machine was developed. The machine was designed and built at the company Ortotip d.o.o. and it is able to produce the parts of up to 130 mm Ž 130 mm Ž 150 mm. After the initial testing, test specimens, according to standards EN ISO 527-2: 2012 and EN ISO 178: 2011, were produced and tested at the facilities of the PEEK manufacturer Invibio (from the UK). The article presents the steps taken when developing the PEEK modelling machine, the test methods to verify the mechanical properties of manufactured products and the results of the material testing. The machine was developed to produce medical implants (specific maxillofacial prosthesis), but with additional testing (that will help to improve the mechanical properties of produced parts) practically all bone-replacement implants can be made.
Ključne besede: PEEK, 3D printer, implant, medical application, thermoplastic, FDM, biocompatible, additive technology
Objavljeno: 17.03.2017; Ogledov: 744; Prenosov: 56
.pdf Celotno besedilo (2,10 MB)
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Human potentials management in transport
Drago Pupavac, Ratko Zelenika, Marinko Jurčević, 2004, kratki znanstveni prispevek

Opis: The paper explores the significance of human potentials management in micro and macro transport systems and investigates to what extent do the human potentials represent the factor of growth and development of transport systems. The facts gathered in this paper should represent the quantitative starting points for viewing the specifics of transport service productions and future movements on the transport labour market, and the possibilities of information technologies implementation in transport human potentials management optimizations, all with the aim of producing new and of improving the inherited comparative advantages of the Croatian transport systems.
Ključne besede: traffic, transport systems, human potential, labour market, information technology
Objavljeno: 02.06.2017; Ogledov: 383; Prenosov: 39
.pdf Celotno besedilo (4,00 MB)
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Challenges in commercializing biomimetic membranes
Mark Edward Perry, Steen Ulrik Madsen, Tine Jørgensen, Sylvia Braekevelt, Karsten Lauritzen, Claus Hélix-Nielsen, 2015, pregledni znanstveni članek

Opis: The discovery of selective water channel proteins-aquaporins-has prompted growing interest in using these proteins, as the building blocks for designing new types of membranes. However, as with any other new and potentially disruptive technology, barriers for successful market entry exist. One category includes customer-related barriers, which can be influenced to some extent. Another category includes market-technical-related barriers, which can be very difficult to overcome by an organization/company aiming at successfully introducing their innovation on the market%in particular if both the organization and the technology are at early stages. Often, one faces barriers from both these categories at the same time, which makes it necessary to gain insight of the particular market when introducing a new innovative product. In this review we present the basic concepts and discuss some of these barriers and challenges associated with introducing biomimetic aquaporin membranes. These include technical issues in membrane production and product testing. Then we discuss possible business models for introducing new technologies in general, followed by a presentation of beach-head market segments relevant for biomimetic aquaporin membranes.
Ključne besede: aquaporin membranes, biomimetic, commercialization, early stage technology
Objavljeno: 21.06.2017; Ogledov: 346; Prenosov: 193
.pdf Celotno besedilo (239,48 KB)
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Biology students' teacher opinions about the integration of ICT into the learning and teaching process
Andreja Špernjak, 2014, izvirni znanstveni članek

Opis: Biology laboratory work can be performed in various ways, even using information and communication technologies (ICT). Whether a teacher incorporates it into laboratory work is related to different factors, but educators can influence students’ beliefs about the value of ICT through their pedagogical practice. In our study, student teachers of biology gave opinions on how successfully university professors use ICT in the classroom, where they acquired most knowledge about ICT and their attitude towards using of ICT in laboratory work. Student teachers were critical about the knowledge and usage of ICT of university professors in class. During their student teachers mostly failed to acquire knowledge about ICT and practice in incorporating it into daily routines. These results will be presented to our university professors, at which time we will suggest how they could use ICT more effectively in daily practice because, on the one hand, they are responsible for students teacher attitudes and for the level of student teacher knowledge, while, on the others, they precipitate indirectly in forming the pupils’ attitudes and determining the level of the pupils’ knowledge of ICT. The study was done on 85 student teachers of biology. Attitudes toward ICT are statistically significant by gender.
Ključne besede: education, information and communication technology, ICT, gender studies
Objavljeno: 06.07.2017; Ogledov: 462; Prenosov: 221
.pdf Celotno besedilo (166,92 KB)
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