Kolektor Group

Magma, Slovenia

Kolektor Group

Magma, Slovenia
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Strauch L.,Kolektor Group | Pavlin M.,University of Ljubljana | Bregar V.B.,Kolektor Group | Bregar V.B.,University of Ljubljana
International Journal of Applied Electromagnetics and Mechanics | Year: 2015

This paper presents a new design of ferrite core made of ferrite bars positioned in radial geometry. New core design is used in inductive wireless power transfer where the optimal design of ferrite bars was analyzed. Numerical simulations of seven ferrite bars geometries were performed in 3D models using Comsol Multiphysics in terms of the coupling coefficient. Two optimal designs of three and nine ferrite bars geometries were used for parameterization of geometric parameters. Both simulations of three and nine ferrite bars geometries were verified by measurements. Optimal design of nine ferrite bars geometry is proposed for use in wireless power transfer because of low consumption of ferrite material. Ferrite bars geometry was also used as a magnetic shield to reduce magnetic fields which may interfere with the electronics nearby. Magnetic flux density in ferrite bars is low enough that prevents ferrite bars from the saturation. The angular alignment of optimal design of nine ferrite bars on the transmitter and receiver side was negligible as the difference in the coupling coefficient was 0.13%. Advantages of using optimal design of nine ferrite bars geometry are: high value of the coupling coefficient, low consumption of ferrite material, and reduced weight. © 2015 - IOS Press and the authors. All rights reserved.


Puliyalil H.,Jozef Stefan Institute | Puliyalil H.,Jožef Stefan International Postgraduate School | Cvelbar U.,Jozef Stefan Institute | Cvelbar U.,Jožef Stefan International Postgraduate School | And 7 more authors.
RSC Advances | Year: 2015

The performance of electrical insulating polymers measured by comparative tracking index can be improved by flame retardant fillers in the polymer-matrix, but is not necessary effective due to persisting surface layers. We demonstrated a method for selective etching of polyphenol-matrix composites which leads to improvement of the tracking properties. Selective etching was performed by low pressure inductively coupled oxygen plasma generated at 35 Pa. Species created in discharge were monitored in situ during the treatment by optical emission spectroscopy (OES). Their surface reactions were established indirectly from X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDXS) after plasma treatment. The effective etching was done by oxygen species which removed off surface polymer layer within 10 to 15 s during plasma pulse operation to prevent surface overheating. The selective polymer removal improved tracking properties of the 70% glass filler reinforced composites up to 56%, whereas the performance level decreased with the decrease in filler content. This technology provides an important enhancement of polymer-matrix composites' tracking properties and resistance of composites to electrical short-circuit fire. © The Royal Society of Chemistry 2015.


Prijic S.,Nanotesla Institute | Prosen L.,Nanotesla Institute | Cemazar M.,Institute of Oncology Ljubljana | Cemazar M.,University of Primorska | And 8 more authors.
Biomaterials | Year: 2012

Cancer immuno-gene therapy is an introduction of nucleic acids encoding immunostimulatory proteins, such as cytokine interleukin 12 (IL-12), into somatic cells to stimulate an immune response against a tumor. Various methods can be used for the introduction of nucleic acids into cells; magnetofection involves binding of nucleic acids to magnetic nanoparticles with subsequent exposure to an external magnetic field. Here we show that surface modified superparamagnetic iron oxide nanoparticles (SPIONs) with a combination of polyacrylic acid (PAA) and polyethylenimine (PEI) (SPIONs-PAA-PEI) proved to be safe and effective for magnetofection of cells and tumors in mice. Magnetofection of cells with plasmid DNA encoding reporter gene using SPIONs-PAA-PEI was superior in transfection efficiency to commercially available SPIONs. Magnetofection of murine mammary adenocarcinoma with plasmid DNA encoding IL-12 using SPIONs-PAA-PEI resulted in significant antitumor effect and could be further refined for cancer immuno-gene therapy. © 2012 Elsevier Ltd.


Mozetic M.,International Union for Vacuum Science | Mozetic M.,Jozef Stefan Institute | Ostrikov K.,International Union for Vacuum Science | Ostrikov K.,CSIRO | And 63 more authors.
Journal of Physics D: Applied Physics | Year: 2014

Recent advances in vacuum sciences and applications are reviewed. Novel optical interferometer cavity devices enable pressure measurements with ppm accuracy. The innovative dynamic vacuum standard allows for pressure measurements with temporal resolution of 2 ms. Vacuum issues in the construction of huge ultra-high vacuum devices worldwide are reviewed. Recent advances in surface science and thin films include new phenomena observed in electron transport near solid surfaces as well as novel results on the properties of carbon nanomaterials. Precise techniques for surface and thin-film characterization have been applied in the conservation technology of cultural heritage objects and recent advances in the characterization of biointerfaces are presented. The combination of various vacuum and atmospheric-pressure techniques enables an insight into the complex phenomena of protein and other biomolecule conformations on solid surfaces. Studying these phenomena at solid-liquid interfaces is regarded as the main issue in the development of alternative techniques for drug delivery, tissue engineering and thus the development of innovative techniques for curing cancer and cardiovascular diseases. A review on recent advances in plasma medicine is presented as well as novel hypotheses on cell apoptosis upon treatment with gaseous plasma. Finally, recent advances in plasma nanoscience are illustrated with several examples and a roadmap for future activities is presented. © 2014 IOP Publishing Ltd.

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