6 research outputs found
Draft amendments to CCIR report 943 and question 48/10: CCIR Study Groups, Doc. Yug 10/1
No full textThis paper presents text of the document of the CCIR Study Groups, for period 1982-1986, and draft amendments to report 1943 and question 48/10 prepared by the author, prof. Dr Jovan Surutka, regular member of Serbian Academy of Sciences and Arts, and accepted by the CCIR Study Groups as Doc. YUG 10/1. The author developed a new method of elimination of the static atmospheric electricity from the guys of LF and MF broadcast antennas
Symmetrical linear antennas driven by two-wire lines
No full textA new theoretical approach to the problem of the symmetrical linear antenna driven by a two-wire line is presented. Then symmetrical linear antenna and the feeder line are treated as a unique boundary-value problem leading to a system of two simultaneous integral equations containing antenna and line currents as unknown sub-integral functions. The integral equations are approximately solved by the so-called point-matching method. Due to the mutual coupling between the antenna and the line, a new conveniently defined apparent driving-point admittance is to be introduced. The method is applied on several types of linear antennas: Centre driven symmetrical dipole antenna, Centre-driven V-antenna, Cage antenna, H-antenna and System of two parallel non-staggered dipoles antennas, positioned in the air over semi-conducting ground. Then theoretical results for admittances were compared with the experiments and remarkably good overall agreement has been found. On the contrary, a comparison with the corresponding theoretical results obtained with the idealized delta-function generator revealed remarkable discrepancies.</jats:p
Symmetrical linear antennas driven by two-wire lines
No full textA new theoretical approach to the problem of the symmetrical linear antenna driven by a two-wire line is presented. Then symmetrical linear antenna and the feeder line are treated as a unique boundary-value problem leading to a system of two simultaneous integral equations containing antenna and line currents as unknown sub-integral functions. The integral equations are approximately solved by the so-called point-matching method. Due to the mutual coupling between the antenna and the line, a new conveniently defined apparent driving-point admittance is to be introduced. The method is applied on several types of linear antennas: Centre driven symmetrical dipole antenna, Centre-driven V-antenna, Cage antenna, H-antenna and System of two parallel non-staggered dipoles antennas, positioned in the air over semi-conducting ground. Then theoretical results for admittances were compared with the experiments and remarkably good overall agreement has been found. On the contrary, a comparison with the corresponding theoretical results obtained with the idealized delta-function generator revealed remarkable discrepancies
Sirovi glicerol i surutka kao izvori ugljenika i azota za produkciju antibiotika
No full textThe microorganisam Streptomyces hygroscopicus CH-7 produces antibiotics Hexaene, Nigericine and Elaiophyline. The yield of antibiotics can be increased by changing the fermentation conditions and the composition of the nutrient medium. Based on the previous research with this strain and the literature reviewed, the aim of this work was to study the possibility of using waste materials (whey with proteins in varying ammounts and crude glycerol from the biodiesel production) as a carbon and nitrogen source in order to increase the yeald of antibiotics produced by Streptomyces hygroscopicus CH-7. The maximum concentration of Hexaene (47,2 μg/ cm3) was achieved in the medium with whey containing 80% of protein and glycerol from sunflower oil, while the maximum concentration of Elaiophyline (24,3μg/cm3) was achived in the basal medium.Mikroorganizam Streptomyces hygroscopicus CH-7 produkuje antibiotike Heksaen, Nigericin i Elaiofilin. Promenom uslova fermentacije i sastava hranljive podloge može se povećati produkcija antibiotika. Na osnovu dosadašnjih istraživanja sa ovim sojem i literaturnog pregleda, cilj ovog rada je bio da se ispita mogućnost primene otpadnih sirovina (surutke sa različitim procentom proteina i sirovog glicerola iz proizvodnje biodizela) kao izvora ugljenika i azota, kako bi se povećala produkcija antibiotika pomoću Streptomyces hygroscopicus CH-7. Maksimalna koncentracija Heksaena (47,2 μg/cm 3) postignuta je na podlozi sa surutkom (koja sadrži 80% proteina) i glicerolom iz suncokretovog ulja, dok je maksimalna koncentracija Elaiofilina (24,3μg/cm3) ostvarena na osnovnoj podlozi
Lives and work of the Serbian scientists
No full textThe Board for the study of lives and work of Serbian scientist and scientists
of Serbian origin, established by the Serbian Academy of Sciences and
Arts in 1992, has been publishing the edition entitled The Lives and Work of
Serbian Scientists for 15 years now. The first volume was published in 1996.
The 15 volumes that have been published so far portray the lives of over 150
scientific experts on nature, mathematics, medicine and technical sciences
all of whom have leaf indelible mark on the world of science itself and the
on Serbian culture in general both of which are greatly indebted to them and
proud of their achievements. Following Volume 10, the Board published a
special book in 2006 which contained English translation of the work summaries
and biographies of 125 scientists mentioned in earlier editions.
This special edition also contained a great deal of useful appendices in
which scientists are classified according to the years of their birth, field of
expertise, and the like. Basic information about the authors of the summaries
has also been included.
Readers now have before them Volume 13 of the Edition which contains
biographies of 11 new scientists: 1 engineer (Jovan Surutka), 2 chemists (Dragutin
Dražić and Milenko Ćelap), 3 physicists (Milenko Šušić, Stevan Koički
and Milan Kurepa), 2 physicians (Bogdan Kosanović and Ivan Spužić), 2 biologists
(Vladimir Pantić and Vojislav Petrović) and 1 geologist (Nikola Pantić).
We are very pleased to once again express our appreciation to all Board
members for their efforts on selecting competent authors and reviewers.
We also welcome all of their comments and suggestions which helped this
book maintain the same quality that the earlier editions are credited with. Acknowledgements
are also extended to Mrs Vera Batina, Board Secretary, and
the authors of particular articles, reviewers, benefactors, technical staff at the
Serbian Academy and the people of the publishing company „Službeni glasnik".Биографије и библиографије / Српска академија наука и уметности : књ. 13. II одељење, Одбор за проучавање живота и рада научника српског порекла ; књ. 1
