{"id":1604,"date":"2020-09-04T22:11:11","date_gmt":"2020-09-04T20:11:11","guid":{"rendered":"http:\/\/websrv.saske.sk\/uef\/en\/?p=1604"},"modified":"2020-09-04T22:12:58","modified_gmt":"2020-09-04T20:12:58","slug":"michal-rajnak-nanomaterials-are-the-most-effective-way-to-more-efficient-cooling-of-electrical-machines","status":"publish","type":"post","link":"https:\/\/websrv.saske.sk\/uef\/en\/michal-rajnak-nanomaterials-are-the-most-effective-way-to-more-efficient-cooling-of-electrical-machines\/","title":{"rendered":"Michal Raj\u0148\u00e1k: Nanomaterials are the most effective way to more efficient cooling of electrical machines"},"content":{"rendered":"

Michal Raj\u0148\u00e1k, former student of the\u00a0Faculty of Humanities and Natural Sciences at\u00a0 University of Pre\u0161ov, had made good and bad decision during his studies;\u00a0by the end of the compulsory pedagogical practice he decided not to become a teacher\u00a0due to the very small interest of students in physics. It is definitely bad for primary and secondary education schools because he certainly has the talent to clearly explain the secrets of physics to students. Yet the decision was very good for the science which he preferred. The greatest evidence is the recent\u00a02019\u00a0<\/b>SAS Award for the results of the research work of the young scientists which he was rewarded already<\/strong>\u00a0as an independent researcher at the Institute of Experimental Physics of the Slovak Academy of Sciences in Ko\u0161ice for significant results in the field of ferromagnetic fluids for applications in electrical engineering.<\/strong><\/p>\n

“At the University of Pre\u0161ov, I felt best in the laboratories which,\u00a0<\/em>thanks to Professor Mari\u00e1n Reiffers, my thesis supervisor, were equipped with top experimental equipment in the field of condensed matter physics”<\/em> says Dr. Michal Raj\u0148\u00e1k about the early\u00a0part of his life journey. Prof. Mari\u00e1n Reiffers, who has been associated with the Institute of Experimental Physics of the Slovak Academy of Sciences in Ko\u0161ice since 1980, directed the young physicist to the topic of his PhD. thesis in the field of magnetic fluids under the supervision of Dr. Milan Timko within the scientific group of assoc. prof. Peter Kop\u010dansk\u00fd.\u00a0Here, as doctoral student at the P. J. \u0160af\u00e1rik University in Ko\u0161ice, he participated in the experimental research of magneto-dielectric properties of ferromagnetic fluids based on transformer oils.<\/p>\n

“During the last year of my doctoral study (in 2015), our team managed to detect interesting reversible structural changes in a ferromagnetic fluid under the influence of an electric field. S<\/em>o far the scientific attention has been given mainly to the intuitive structuring of magnetic fluids in a magnetic field, and therefore we decided to deal more intensively with the structure and dynamics of ferromagnetic fluids in the electric field.\u00a0Our recent experimental results suggest that polarized clusters of magnetic nanoparticles impact\u00a0the distribution of the electric field in a magnetic fluid\u00a0and may serve as pinning centers\u00a0for free electric charge. It is possible that this is why the ferromagnetic fluid can withstand higher electrical voltages than pure transformer oil,”\u00a0<\/em>said Michal Raj\u0148\u00e1k, who has been focusing his scientific research on magnetic fluids for applications in electrical engineering since 2018.\u00a0Demands for the power\u00a0systems are rising and scientists are expected to bring new solutions to improve cooling mediums and increase their efficiency. It turns out that nanomaterials are one of the most promising ways: “On the other hand, the structuring of a ferromagnetic fluid in an electric field opens up new possibilities for research and potential applications. As we suggested in our recent work (Phys. Rev. Applied 11, 024032), phenomena related to electrically controlled structuring of magnetic fluids can find\u00a0use in the field of sensory applications,\u00a0switching and possibly nanorobotics,”<\/em>\u00a0adds Michal Raj\u0148\u00e1k.<\/p>\n

The young scientist is involved in several research projects. He is currently leading two national research projects.\u00a0Within the scope of the APVV project for applied research NANOELEN – Nanofluids in electrical engineering (2019 – 2023), he is working as the project coordinator on\u00a0the research, development and application of alternative ferromagnetic nanofluids for cooling and electrical insulation of electrical transformers.\u00a0He is experimentally investigating the dielectric, magnetic and thermal properties of ferromagnetic nanofluids based on the contemporary transformer oils. The research is done in cooperation\u00a0with the Technical University in Ko\u0161ice and with the industrial partner\u00a0Elektrotechnick\u00fd v\u00fdskumn\u00fd a\u00a0projektov\u00fd \u00fastav (“Electrotechnical research and projecting company”)\u00a0in Nov\u00e1 Dubnica, which tests\u00a0the investigated nanofluids in model transformers under various load regimes. His second project\u00a0Structure and Dynamics of Magnetic Fluids in an Electric Field (2\/0011\/20, 2020 – 2023) by\u00a0VEGA\u00a0focuses on basic research of structure and dynamics of ferromagnetic nanofluids in an external electric field. He is looking for a way to describe the unclear mechanism of conductive streamer development in ferromagnetic nanofluids. In addition to this research he also\u00a0investigates structuring phenomenas in ferromagnetic nanofluids at the macro- and nano-level. He publishes his scientific results in peer-reviewed scientific journals. At the age of 33, he is the first author of seventeen publications and already has seventy entries in the list of co-authored publications.<\/p>\n

Among other various awards, let us mention last year’s first place in the competition of young scientists of SAS under 35 years of age within the 1st Department of Life Sciences for his work “Magnetic Fluids for Applications in Electrical Engineering”. In 2017, he won the Young Physicists Competition, organized by the Slovak Physical Society.<\/p>\n

Michal Raj\u0148\u00e1k develops his expertise based on his knowledge of electrical engineering, for which he is grateful to his grandfather. He spent many moments on his farm in Vy\u0161n\u00fd Hru\u0161ov during his childhood. He is also grateful for the love of nature: “My wife and I live in Pre\u0161ov, I commute to Ko\u0161ice by train which, by the way, I like very much, but my heart beats for relax in nature and work around the house.\u00a0I try to travel to my heritage at least once or twice a week where I have started beekeeping.<\/em>\u00a0I chose the scientific approach; first I completed a course and studied literature,”\u00a0<\/em>adds Michal Raj\u0148\u00e1k with a smile.<\/p>\n

Although the coronavirus pandemic has limited his intentions to travel to\u00a0international short-term internships and conferences\u00a0(such as The 11th Conference on Broadband Dielectric Spectroscopy and its Applications in Spain),\u00a0he praises that he was able to finish articles and process measured data.\u00a0What will he focus on in the near future?\u00a0“Until the end of the year, I will be doing\u00a0measurements for colleagues on a vibrating magnetometer and write an article about the structure of the ferromagnetic fluid under the simultaneous influence of the electric and magnetic field. In addition, me and my colleagues, as well as engineering and doctoral students, are trying to experimentally determine whether there is an electromagnetic bond in magnetic fluids. We want to find out whether, in addition to the geometric structure, it is possible to induce magnetic interactions\u00a0by electric forces between\u00a0magnetic nanoparticles, which under normal conditions do not interact magnetically. We believe that finding answers to questions about electromagnetic coupling or the mechanism of electrical jump\u00a0in ferromagnetic fluids will help to remove some of the barriers\u00a0that hinder the technological transfer of ferromagnetic fluids to the electrical engineering industry,<\/em>”\u00a0<\/em>said Michal Raj\u0148\u00e1k.<\/p>\n

Original author and photo: Katar\u00edna \u010ci\u017em\u00e1rikov\u00e1
\nOriginal text: News at SAS<\/a> (published on September 4, 2020)<\/p>\n","protected":false},"excerpt":{"rendered":"

Michal Raj\u0148\u00e1k, former student of the\u00a0Faculty of Humanities and Natural Sciences at\u00a0 University of Pre\u0161ov, had made good and bad decision during his studies;\u00a0by the…<\/p>\n","protected":false},"author":19,"featured_media":1608,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"_links":{"self":[{"href":"https:\/\/websrv.saske.sk\/uef\/en\/wp-json\/wp\/v2\/posts\/1604"}],"collection":[{"href":"https:\/\/websrv.saske.sk\/uef\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/websrv.saske.sk\/uef\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/websrv.saske.sk\/uef\/en\/wp-json\/wp\/v2\/users\/19"}],"replies":[{"embeddable":true,"href":"https:\/\/websrv.saske.sk\/uef\/en\/wp-json\/wp\/v2\/comments?post=1604"}],"version-history":[{"count":13,"href":"https:\/\/websrv.saske.sk\/uef\/en\/wp-json\/wp\/v2\/posts\/1604\/revisions"}],"predecessor-version":[{"id":1618,"href":"https:\/\/websrv.saske.sk\/uef\/en\/wp-json\/wp\/v2\/posts\/1604\/revisions\/1618"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/websrv.saske.sk\/uef\/en\/wp-json\/wp\/v2\/media\/1608"}],"wp:attachment":[{"href":"https:\/\/websrv.saske.sk\/uef\/en\/wp-json\/wp\/v2\/media?parent=1604"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/websrv.saske.sk\/uef\/en\/wp-json\/wp\/v2\/categories?post=1604"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/websrv.saske.sk\/uef\/en\/wp-json\/wp\/v2\/tags?post=1604"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}