Magnetic Fluids’ Heating Power Exposed to a High-Frequency Rotating Magnetic Field

Magnetic fluids are superparamagnetic materials that have recently been the subject of extensive research because of their unique properties. Among them is the heating effect when exposed to an alternating magnetic field, wherein the objective is to use this property in medicine as an alternative method for the treatment of tumors in the body. The heating effect characterization for the alternating magnetic field (AMF) has been studied widely, whilst for the rotational magnetic field (RMF), no systematic study has been done yet. In this article, we present the characterization of the heating power of magnetic fluids in a high-frequency rotational magnetic field. The results show similar behavior of heating power or specific absorption rate characteristics as in AMF

The influence of row spacing on seed yield, yield components and seed quality of alfalfa

In order to determine the influence row spacing has on yield, yield components and the quality of alfalfa in agro-ecological conditions of south Serbia, a three year long research has been conducted, testing the NS Novosadjanka H-11 cultivar of alfalfa. The average seed yield of alfalfa was highest at a row spacing of 40 cm (311.03 kg ha-1), followed by row spacings of 20 cm (286.48 kg ha-1) and 60 cm (264.83 kg ha-1). The highest and lowest number of inflorescences per stem were obtained in rows spaced 60 cm (14.39 inflorescences/stem) and 20 cm apart (9.94 inflorescences/stem), respectively. The widest row spacing of 60 cm (8.14 pods/inflorescence) resulted in the highest number of pods per inflorescence, whereas the lowest number was produced at 20 cm spacing (5.96 pods/inflorescence). Grain number per pod ranged from 3.64 (at 20 cm row spacing) to 4.18 (at 60 cm). The highest quality of alfalfa seed during the three years of research was obtained at the widest row spacing (60 cm). Thousand-seed weight was highest at 60 cm and lowest at 20 cm (2.05 g and 1.99 g, respectively). The highest average values for seed germination rate were reported for 60 cm row spacing (86.92%) and the lowest for 20 cm row spacing (83.83 %)

Influence of seed pre-treatment and temperatures during germination of four seed lots of Festulolium

A species called Festulolium was created in the middle of the last century by crossing two genuses: Lolium and Festuca. This was followed by a period of research on Festulolium from the aspect of genetics and breeding, seed production, cultivation, technology and use. We conducted various pre-treatment impact studies on Festulolium seeds: i) cooling at 5-7 oC for 3 days, ii) application of KNO3 on seed germination medium, and the third pre-treatment was control, without pre-treatment (iii). After pre-treatment (i, ii, iii), seed germination have examined at the following temperature regimes (provided by the seed quality regulations): 20 oC (dark); alternately 20oC/ 30oC (light /dark); and 30 oC (dark). The tests were performed on four seed lots of the variety Peron, in four replicates. The germination temperature of 30 oC reduced germination and increased dead seed and abnormal germination in all pre-treatments. The variant without the application of pre-treatment had a significantly lower overall germination in the assessment of Festulolium seed quality. Seed lots showed a high influence on the Festulolium seed quality

Effect of crop density on yield and quality of alfalfa forage from combined use (forage-seed)

In Serbia, alfalfa is the most important perennial forage legume that is grown at 180-200 thousand hectares. Except for the classic production of forage, alfalfa is very important for seed production. In our conditions Alfalfa seed are produced from the second cut of alfalfa. Higher seed yields are achieved in larger distances between rows. In this system of production first and third cut are used for fodder. This trial tests three different densities and four varieties in order to determine the impact on yield and quality of forage dry matter. In the year of establishment, cultivars from the treatment A1 achieved higher yields of dry matter for 2.3 t ha-1 in relation to the treatment A2. In the second year, yield was higher by 1.4 t ha-1, and in the third higher for 3.1 t ha-1. Treatment A1 compared to A3 treatment had a higher yield of 3.5 t ha-1 (52%). In the second year treatment A1 achieved higher yields of forage then treatment A3 for 3.8 t ha-1 (44%), and in the third year for 4.6 t ha-1 (56%). Cultivars were also significantly affected the yield of forage dry matter at all densities. Influence of density and variety to the chemical composition of forage and the content of macro elements in the forage had no significant effect

Prinos semena crvenog vijuka (Festuca rubra L.) i korelaciona međuzavisnost sa komponentama prinosa i kvalitetom semena

The paper presents the results of two years of research conducted in eastern Serbia (2007-2008). Tests were conducted with domestic varieties K-14, which was developed at the Institute for Forage Crops, Krusevac. At two different densities B1 (the inter-row distance of 12.5 cm and 15 kg ha-1 seed) and B2 (25 cm row spacing and 7.5 kg ha-1 seed) following components of yield were observed: plant height (cm), number of generative stems, inflorescence length (cm), number of branches in umbel; seed yield (kg ha-1) The following parameters of seed quality were: 1000 seed weight (g), germination energy (%), germination of seeds (%). Interdependence of the traits was determined by simple correlation coefficients (r). The highest seed yield was recorded in density B2. Variability of seed yield was high (CV = 49.9%), because influence of year and plant density. Seed yield achieved the strongest positive correlation (p ≤ 0.01), with generative stems (r=0.994). Also strong dependence was found between plant height and number of generative stems (r=0.977).Rad prikazuje rezultate dvogodišnjih ispitivanja sprovedenih u istočnoj Srbiji (2007­ 2008). Ispitivanja su izvedena sa domaćom sortom K-14, koja je stvorena u Institutu za krmno bilje, Kruševac. Na dve različite gustine: B1 (setva na međuredno rastojanje 12,5 cm i sa 15 kg ha-1 semena) i B2 (25 cm međuredno rastojanje i 7,5 kg ha-1 semena) praćene su sledeće komponente prinosa: visina stabljike (cm), broj generativnih stabljika, dužina cvasti (cm), broj grana u cvasti, prinos semena (kg ha-1). Praćeni su sledeći parametri kvaliteta semena: masa 1000 semena (g), energija klijanja (%), ukupna klijavost semena (%). Međuzavisnost ispitivanih osobina utvrđena je prostim koeficijentima korelacije (r). Veći prinos semena ostvaren je sa gustinom B2. Varijabilnost prinosa pod uticajem godine i gustine, bila je visoka (CV =49,9%). Prinos semena ostvario je najjaču pozitivu korelativnu međuzavisnost (p≤0,05) sa generativnim stabljikama (r=0,994). Takođe jaka zavisnost utvrđena je između visine stabljika i broja generativnih stabljika (r=0,977)

Uticaj načina čuvanja semena na klijavost i vigor klijanaca livadskog i visokog vijuka nakon pet godina

In our tests, the seeds were stored for five years at temperatures of 4 °C, 18 °C in a warehouse conditions (factor method of seed storage). Seed was stored at all temperatures in the paper, a cloth and plastic bags (factor package for seed storage). It was used the seed of meadow and tall fescue (factor species). For testing was used the three lots by both species (factor seed lots). At five years old seed germination was determined in accordance with the ISTA rules (on filter paper, and at temperature of 20 °C in the dark). Vigor was determined by measuring each seedling (root length cm, shoot length cm and biomass of seedlings g.). The factor method of seed storage and packaging factor was significantly acted in germination and vigor (P lt 0.05, P lt 0.01), which influenced to meet germination of seeds for placing on the market (germination gt 75 %). Other examined factors (species and lots) did not have significant effect on seed germination and seedling vigor after five years of storage.Livadski vijuk (Festuca pratensis Huds.) je značajna krmna vrsta koja se koristi uglavnom za smeše sa višegodišnjim krmnim leguminozama. Visoki vijuk je (Festuca arundinacea Schreb.) je vrsta koja je veoma srodna livadskom vijuku koja se pored korišćenja sa krmnim leguminozama za proizvodnju kvalitetne krme, koristi i za zasnivanje travnjaka specijalnih namena takođe uglavnom u smeši sa odgovarajućim višegodišnjim leguminozama (parkovi, sportcki tereni, okućnice i sl.). U našim ispitivanjima seme je čuvano pet godina na temperaturama: 4oC, 18oC i u magacinskim uslovima (faktor način čuvanja semena). Seme je na svim temperaturama čuvano u papirnim, platnenim i plastičnim kesama (faktor anbalaža za čuvanje semena). Za ispitivanje je korišćeno seme po tri partije (faktor partija semena) od ispitivanih vrsta: livadckog, i visokog vijuka (faktot vrsta). Faktori način čuvanja semena, anbalaža u kojoj je seme čuvano i, vrsta kao i nihove interakcije su delovali značajno na klijavost i vigor klijanaca (P≤ 0,05, P≤ 0,01) što je i uticalo na zadovoljenje klijavosti za stavljanje semena u promet (klijavost gt 75%). Ostali, ispitivani faktor (partija) nije imao značajnog uticaja na klijavost semena i vigor klijanaca nakon pet godina čuvanja

Uticaj temperature vazduha tokom sušenja na klijavost i dormantnost semena ježevice (Dactylis glomerata L.)

Cocksfoot is one of the most important forage grasses, with specific reference to arid conditions. It is mainly used as a component for the preparation of grass-legume forage mixtures. One of the major problems in the production of grass seed is seed dispersal and loss of some yeld. However, harvesting can be done before the stage of technological maturity of seeds where the losses are reduced but, the quality of the seed may be a problem in this case. On the other hand immediately after harvesting, as well as a period of time after harvesting the seed, the grass is characterized by the presence of dormant seeds. Seed dormancy can be decreased with optimum temperature and moisture during the air seed drying. The harvested seed had the moisture content from 20% to 35%. Then the seeds are dried at temperatures of 90oC, 80oC, 70oC, 60oC, 50oC, 40oC, 30oC and at all temperatures the seeds exhibited 90, 60, 30 minutes. In laboratory conditions, seed germination (%), dormant seed are determined in six genotypes. Selection of the optimal temperature and drying time can significantly effect on the increase in seed germination of both seed moisture. Genotypes with high moisture according to the germination, showed low variability (moisture content was 20% and CV ranged from 2.0 to 4.1%; moisture content was 35% and CV ranged from 1.8 to 3.9%).Ježevica je jedna od najznačajnijih krmnih trava, sa posebnim značajem za aridne uslove. Uglavnom se koristi kao komponenta za sastavljanje travno-leguminoznih krmnih smeša. Jedan od većih problema u proizvodnji semena trava je osipanje semena i gubitak dela prinosa. Međutim žetvu je moguće obaviti i pre faze tehnološke zrelosti semena gde se gubici smanjuju ali može biti problem sa kvalitetom semena. Na drugoj strani odmah nakon ubiranja žetve kao i neki vremenski periodpo žetvi semena, trave se odlikuju prisutnošću dormantnog semena. Ućešće dormantnog semena se može smanjiti a povećati klijavost uticajem optimalne temperature vazduha prilikom sušenja gde i vlažnost semena ima uticaja. Ispitivano je seme sa sadržajem vlage: 20% i 35%. Zatim je seme sušeno na temperaturama vazduha: 90oC, 80oC, 70oC, 60oC, 50oC, 40oC, 30oC i klasično. Seme je vremenski izlagano na pomenutim temperaturama vazduha 90, 60 i 30 minuta. U laboratoriskim uslovima utvrđivana je klijavost ( % ) i dormantnost semena ( % ) šest genotipova ježevice. Izborom optimalne temperature vazduha i vremenom sušenja moguće je značajno uticati na povećanje klijavosti semena obe vlažnosti. Genotipovi sa visokom klijavošću su prema klijavosti ispoljili nisku varijabilnost (vlažnost 20% CV = 2,0-4,1%; vlažnost 35% CV = 1,8-3,9%)

Varijabilnost klijanja semena trećeg dana i početnog porasta klijanaca hibrida suncokreta pri različitim temperaturama

U radu su prikazani rezultati ispitivanja klijavosti semena i početnog porasta klijanaca četiri hibrida suncokreta (2950, 2951, 3007, 3009) pri različitim temperaturama: 20, 25 i 30 °C. Kod svih ispitivanih hibrida najviše klijanje semena suncokreta ostvareno je na temperaturi od 30 °C, međutim, na dva ispitivana hibrida (2950 i 3007) nije nađena značajna razlika (p ≥ 0,05) između klijavosti na temperaturi 30 i 25 °C. Korelacionom međuzavisnošću između klijavosti i porasta stabaoceta utvrđena je pozitivna i statistički značajna razlika (r=0,576- p ≤ 0,05), dok je između klijavosti i porasta korenka utvrđena takođe pozitivna međuzavisnost, ali ne i statistički značajna razlika (r=0,252- p ≥ 0,05)

Effect of seed aging on the seed quality and seedling growth of timothy grass (Phleum pratense L.)

Timothy grass is a fodder grass mostly grown as a pure stand or in mixed stands with fodder legumes at higher elevations. It is cultivated for its high yields and the supreme quality of roughage containing Timothy grass. There are different methods for preserving the seed quality of fodder grasses relative to the following parameters: species, variety, harvest methods, postharvest treatments, as well as the storage temperature and air humidity. Poor seed germination is often caused by the presence of dormant seeds which fail to germinate despite ideal conditions in the field or laboratory. After a certain storage period, dormant seeds start germinating, but prolonged storage periods result in seed aging which is associated with reductions in seed germination, seedling growth and the total mass of the root system. The seed quality features of four Timothy grass seed lots (the 'Foka' cultivar), at ages of 3, 15 and 27 months, were examined in this study according to the share of dormant, germinated and dead seeds, as well as abnormal seedlings. Upon assessing seed germination, the stem length (cm), radicle length (cm) and fresh weight (g) of seedlings were measured. Different seed lots were found to exert no effect on the seed quality parameters examined and the growth of seedlings. Conversely, the seed age had a significant impact (P <0.001 to P <0.05) on the seed quality parameters examined and the seedling growth.Mačji rep je krmna trava koja se uglavnom gaji u smeši sa krmnim leguminozama ili kao čist usev na većim nadmorskim visinama. Njegovim gajenjem se ostvaruju visoki prinosi i odličan kvalitet kabaste stočne hrane. Za razliku od većine krmnih trava, mačji rep nije sklon osipanju pa se ubiranje semena obavlja kada je seme sa nižim sadržajem vlage što je zbog značajno zbog dužeg održanja kvaliteta semena. Postoje razlike u očuvanju kvaliteta semena između krmnih trava. U značajnije faktore spadaju: vrsta, sorta, način ubiranja, posležetveni tretmani semena, kao i temperatura i vlažnost vazduha u skladištu. Smanjenu klijavost često uzrokuje prisustvo dormantnog semena koje ne klija iako postoje idealni uslovi u laboratoriji ili na polju. Nakon određenog perioda skladištenja dormantno seme postaje klijavo. Produženjem vremena skladištenja dolazi do starenja semena, što se ogleda u smanjenoj klijavosti a vrlo često i u smanjenom porastu klijanaca i ukupnoj masi korenovog sistema. Ova istraživanja su izvedena na četiri partije semena mačjeg repa sorte Foka. Analiziran je kvalitet semena (udeo dormantnog, klijavog, mrtvog semena i nenormalnih klijanaca) kod semena starog tri, petnaest i dvadeset sedam meseci. Nakon utvrđivanja klijavosti, na klijancima su izmereni stabaoce (cm), korenak (cm) i masa svežih klijanaca. Partija semena nije imala značajnog uticaja na ispitivane parametre kvaliteta semena, kao i ni na porast klijanaca. Sa druge strane, starost semena je imala značajan uticaj (P <0.001 do P <0.05) na ispitivane parametre kvaliteta semena