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1.
Experimental testing of single APM spheres
Matej Vesenjak, Lovre Krstulović-Opara, 2010, objavljeni znanstveni prispevek na konferenci

Opis: Advanced pore morphology (APM) foam, consisting of sphere-like metallic foam elements, proves to have advantageous mechanical properties and unique application adjustability. Since the APM foam manufacturing procedure has been developed recently, the mechanical characterization of these materials is still very limited. Therefore, the purpose of this research was to determine the behaviour of APM spheres and its composites when subjected to quasi-staticand dynamic compressive loading. The results of the performed research have shown valuable mechanical properties of the composite APM foam structures, offering new possibilities for their use in general engineering applications.
Ključne besede: advanced pore morphology, foam, composite APM foam structures
Objavljeno: 26.07.2017; Ogledov: 2; Prenosov: 0
.pdf Polno besedilo (1,61 MB)

2.
Effect of low-density static magnetic field on the oxidation of ammonium by Nitrosomonas europaea and by activated sludge in municipal wastewater
Jasmina Filipič, Ines Mandić-Mulec, Brigita Tepuš, Vanja Kokol, Barbara Kraigher, 2015, izvirni znanstveni članek

Opis: Ammonium removal is a key step in biological wastewater treatment and novel approaches that improve this process are in great demand. The aim of this study is to test the hypothesis that ammonium removal from wastewater can be stimulated by static magnetic fields. This was achieved by analysis of the effects of static magnetic field (SMF) on the growth and activity of Nitrosomonas europaea, a key ammonia-oxidising bacterium, where increased growth and increased ammonia oxidation rate were detected when bacteria were exposed to SMF at 17 mT. Additionally, the effect of SMF on mixed cultures of ammonia oxidisers in activated sludge, incubated in sequencing batch bioreactors simulating wastewater treatment process, was assessed. SMFs of 30 and 50 mT, but not of 10 mT, increased ammonium oxidation rate in municipal wastewater by up to 77 % and stimulated ammonia oxidiser growth. The results demonstrate the potential for use of static magnetic fields in increasing ammonium removal rates in biological wastewater treatment plants.
Ključne besede: odpadne vode, bakterije, Nitrosomonas europaea, statično magnetno polje, biološke čistilne naprave, nitrifikacija
Objavljeno: 24.07.2017; Ogledov: 17; Prenosov: 0
.pdf Polno besedilo (323,02 KB)

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Ogrevanje pasivne hiše, podprto s sončno energijo
Aleksander Grobin, 2017, diplomsko delo/naloga

Opis: Za ogrevanje zgradb se porabi veliko energije, pri pridobitvi katere onesnažujemo okolje. Onesnaževanje lahko zmanjšamo z energetsko varčnejšimi objekti in z energijo, pridobljeno iz obnovljivih virov. V diplomskem delu primerjamo enaki pasivni hiši, ogrevani s sončno energijo prek sončnega toplotnega sistema. Geografsko sta postavljeni na različnih lokacijah, v Mariboru in pri Bertokih. Pričakovano je za ogrevanje hiše pri Bertokih potrebne manj energije kot za ogrevanje hiše v Mariboru, zaradi večjega sončnega obsevanja na Primorskem je potrebna velikost sistema manjša pri Bertokih. Velikost sistema vpliva na ceno investicije. Primerjali smo tudi cene investicije v sistem za ogrevanje z drugimi viri energije.
Ključne besede: solarni toplotni sistem, sončna energija, pasivna hiša, ogrevanje
Objavljeno: 18.07.2017; Ogledov: 39; Prenosov: 2
.pdf Polno besedilo (2,51 MB)

5.
Numerical simulation of force interactions between rigid bodies and fluid flow
Ožbej Verhnjak, 2017, magistrsko delo/naloga

Opis: Particles immersed in a fluid have always been an important researching domain in process technologies, pharmacy and fluid mechanics. It is for its practical utility in industry that the two-phase flow is still being academically researched, but in present times with a slightly different, more complex approach. Formerly all the particles have been assumed to be spheres, what simplified the models of processes physical presentation. Nowadays, however, it is clear that such an assumption makes significant errors in some fields of applications. With that reason ellipsoids were presented instead of spheres. That step also transferred computation from analytical or partially analytical to wholey numerical. This work presents the results of numerical simulation of different ellipsoids and sphere. In addition a Saffmann effect on sphere is presented as a special phenomena in fluid mechanics.
Ključne besede: OpenFOAM, Saffman effect, drag coefficient, sphere drag, drag on ellipsoids, forces on immersed bodies
Objavljeno: 17.07.2017; Ogledov: 17; Prenosov: 2
.pdf Polno besedilo (2,30 MB)

6.
Vodenje linearne osi s koračnim motorjem
Tadej Steničnik, 2017, magistrsko delo/naloga

Opis: Zasnovana in izdelana je elektromehanska, demonstracijska, linearna enota. Za doseganje zahtevanega položaja je uporabljena linearna os, ki jo načeloma lahko premika tako koračni motor kot tudi servomotor. Poudarek je na uporabi koračnega motorja. Osrednji namen je enostavno in nazorno prikazati, kako na regulacijo vplivajo posamezni členi regulatorja, vrsta regulatorja, nastavljeni parametri ter izbran pogonski motor. Uporaba sistema je preprosta, saj je potrebno v uporabniški vmesnik le vnesti zahtevane podatke in linearno os pognati. Nato preko grafičnega vmesnika spremljamo obnašanje sistema ter delovanje regulatorja. Možno je tudi analizirati gibanje linearne osi ter primerjati odzive na spremembe vhodnih parametrov. Na ta način je mogoče testirati različne koncepte vodenja oziroma regulatorje do skrajnih meja zmogljivosti, ki jih dopušča uporabljeni motor. Pri tem pa ni bojazni, da bi prišlo do poškodovanja opreme.
Ključne besede: linearna enota, koračni motor, vodenje osi
Objavljeno: 12.07.2017; Ogledov: 67; Prenosov: 11
.pdf Polno besedilo (3,17 MB)

7.
Mathematical model for the selection of processing parameters in selective laser sintering of polymer products
Ana Pilipović, Igor Drstvenšek, Mladen Šercer, 2014, izvirni znanstveni članek

Opis: Additive manufacturing (AM) is increasingly applied in the development projects from the initial idea to the finished product. The reasons are multiple, but what should be emphasised is the possibility of relatively rapid manufacturing of the products of complicated geometry based on the computer 3D model of the product. There are numerous limitations primarily in the number of available materials and their properties, which may be quite different from the properties of the material of the finished product. Therefore, it is necessary to know the properties of the product materials. In AM procedures the mechanical properties of materials are affected by the manufacturing procedure and the production parameters. During SLS procedures it is possible to adjust various manufacturing parameters which are used to influence the improvement of various mechanical and other properties of the products. The paper sets a new mathematical model to determine the influence of individual manufacturing parameters on the polymer product made by selective laser sintering. Old mathematical model is checked by statistical method with central composite plan and it is established that old mathematical model must be expanded with new parameter beam overlay ratio. Verification of new mathematical model and optimization of the processing parameters are made on SLS machine.
Ključne besede: manufacturing system, inteligent methods, 3D scanning
Objavljeno: 12.07.2017; Ogledov: 49; Prenosov: 0
.pdf Polno besedilo (1,43 MB)

8.
An approach to consider the arterial residual stresses in modelling of a patient-specific artery
Janez Urevc, Miroslav Halilovič, Milan Brumen, Boris Štok, 2016, izvirni znanstveni članek

Opis: In this work, the residual stress state of a human common carotid artery is predicted using the so-called thermomecha- nical analogy approach. The purpose of the approach is to enable consistent mapping of residual stresses and the respec- tive configuration from a circular arterial segment to a patient-specific arterial geometry. This is achieved by applying proper volumetric dilatations to the actual arterial stress-free in vivo geometry, which makes use of the analogy that states that the bending stresses can be obtained on an equivalent manner by applying proper thermal dilatations. The common carotid artery data are obtained in vivo from a healthy 28-year-old man using non-invasive methods. The pre- dicted residual stresses of the common carotid artery are in good quantitative agreement with the data from prior work in this field. The approach is validated by predicting the common carotid artery zero-stress state configuration, where a sector-like (cut-open) state is obtained. With this approach, it is thus possible to predict the residual stresses as well as the configuration of patient-specific arterial geometry without the need to model its cut-open zero-stress configuration.
Ključne besede: patient-specific artery, common carotid artery, residual stresses, arterial zero-stress state, thermomechanics, finite element method
Objavljeno: 12.07.2017; Ogledov: 42; Prenosov: 0
.pdf Polno besedilo (3,97 MB)

9.
Zasnova programa v MS Excel za podporo preventivnega vzdrževanja
David Šalamun, 2017, diplomsko delo/naloga

Opis: Preventivno vzdrževanje se spreminja podobno, kot se spreminja tehnologija industrijskih strojev. V nalogi je predstavljena izdelava programa, ki služi vzdrževalcem v podjetju Talum Servis in inženiring d. o. o. pri opravljanju preventivnih pregledov obratov. Program je bil izdelan v programskem okolju Microsoft Office znotraj programov Excel in Word. V nalogi so poleg teorije, opisani tudi posamezni postopki preventivnega vzdrževanja in morebitne težave ter nevarnosti, na katere mora biti vzdrževalec pri pregledu pozoren. Glavni namen programa je takojšnje podajanje navodil za vzdrževanje, beleženje zgodovine posegov vzdrževanja in avtomatizirano izdelavo poročila o posegu na posameznem stroju.
Ključne besede: preventivno vzdrževanje, Excel, Talum Servis in inženiring d. o. o., livarstvo, pnevmatika in hidravlika
Objavljeno: 12.07.2017; Ogledov: 26; Prenosov: 7
.pdf Polno besedilo (2,00 MB)

10.
Rigid body dynamics in optimization of the machine tool vibroisolation
Radomir Slavković, Aleksandar Veg, Nedeljko Dučić, Nikola Slavković, Jelena Baralić, Ivan Milićević, 2015, izvirni znanstveni članek

Opis: Modern design of the machine tool treats the suspending parts as a crucial element of the effective vibration isolation. Therefore the suspending items are specifically developed and subjected to extensive tests before being applied on real objects. These elements ensure accurate levelling and appropriate vibration damping. Usually selection of inadequate support element causes intensive disturbing effects in machining. The paper presents dynamics analysis of the machine tool suspended on flexible mountings. The overall analysis is conceived on a rigid body dynamics. This method enables selection of an optimal supporting configuration. Further on such an effective suspension design prevents a need for expensive monitoring of the dynamic characteristics of the mechanical system, i.e. machine tool and supports. The paper explores dynamics of a real, flexibly supported machine tool. Results are obtained with the assistance of the "SUPPORT" software. Finally the theoretical and computational statements are approved throughout extensive site measurements on the machine tool body with appropriate instrumentation.
Ključne besede: dynamics analysis, experiment, machine tool, software, transfer function
Objavljeno: 12.07.2017; Ogledov: 20; Prenosov: 0
.pdf Polno besedilo (2,13 MB)

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