395 research outputs found

    Stark broadening data for spectral lines of rare-earth elements: Nb III

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    The electron-impact widths for 15 doubly charged Nb ion lines have been theoretically determined by using the modified semiempirical method. Using the obtained results, we considered the influence of the electron-impact mechanism on line shapes in spectra of chemically peculiar stars and white dwarfs.Comment: 10 pages, 2 figures, 1 table, accepted in Advances in Space Researc

    Analysis of Radar Doppler Signature from Human Data

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    This paper presents the results of time (autocorrelation) and time-frequency (spectrogram) analyses of radar signals returned from the moving human targets. When a radar signal falls on the human target which is moving toward or away from the radar, the signals reflected from different parts of his body produce a Doppler shift that is proportional to the velocity of those parts. Moving parts of the body causes the characteristic Doppler signature. The main contribution comes from the torso which causes the central Doppler frequency of target. The motion of arms and legs induces modulation on the returned radar signal and generates sidebands around the central Doppler frequency, referred to as micro-Doppler signatures. Through analyses on experimental data it was demonstrated that the human motion signature extraction is better using spectrogram. While the central Doppler frequency can be determined using the autocorrelation and the spectrogram, the extraction of the fundamental cadence frequency using the autocorrelation is unreliable when the target is in the clutter presence. It was shown that the fundamental cadence frequency increases with increasing dynamic movement of people and simultaneously the possibility of its extraction is proportional to the degree of synchronization movements of persons in the group

    Stark broadening of B IV lines for astrophysical and laboratory plasma research

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    Stark broadening parameters for 36 multiplets of B IV have been calculated using the semi-classical perturbation formalism. Obtained results have been used to investigate the regularities within spectral series and temperature dependence.Comment: 8 pages, 6 figures, 1 table, in press in Advances in Space Researc

    Uticaj gustine zasnivanja na prinos krme žutog zvezdana gajenog za kombinovano korišćenje

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    Birdsfoot trefoil grown for seed (cv. Bokor) was examined in agroecological conditions of Western Serbia during period 2007-2009. The goal was to determine herbage yield which could be achieved growing seed crop, using different interrow spacing (12.5, 25 and 50 cm) and various seeding rates (2, 4 and 8 kg ha-1). The highest hay yield was obtained in the third production year at the narrowest spacing and using the highest seeding rate (5.26 t ha-1). Total hay production during 3 years using birdsfoot trefoil seed crop for herbage yield ranged from 9.11 to 14.83 t ha-1 depending on row spacing and from 10.74 to 13.2 t ha-1 depending on seeding rate. The highest stand density (8 kg ha-1 seeding rate and 12.5 cm interrow spacing) produced the highest herbage yield of birdsfoot trefoil in the combined usage (for forage and seed production).Žuti zvezdan za proizvodnju semena, sorte Bokor, ispitivan je u agroekološkim uslovima zapadne Srbije, u periodu 2007-2009. godine. Ispitivana je količina biomase koja se može dobiti gajenjem žutog zvezdana za seme, pri zasnivanju na različitom međurednom rastojanju (12,5, 25 i 50 cm) i sa različitom normom semena (2, 4 i 8 kg ha-1). Najveći prinosi sena ostvareni su u trećoj godini gajenja useva na najužem međurednom rastojanju od 12,5 cm (6,56 t ha-1) i pri najvećoj količini semena od 8 kg ha-1 (5,73 t ha-1). Ukupna produkcija sena u trogodišnjem periodu korišćenja semenskog useva žutog zvezdana bila je od 9,11 do 14,83 ha-1 u zavisnosti od međurednog rastojanja i od 10,74 do 13,20 ha-1 u zavisnosti od setvene norme. Žuti zvezdan u kombinovanom korišćenju (za seme i krmu) je imao najveći potencijal za prinos krme pri većoj gustini zasnivanja (8 kg ha-1 i 12,5 cm međuredno rastojanje)

    Stark broadening of B IV spectral lines

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    Stark broadening parameters for 157 multiplets of helium like boron (B IV) have been calculated using the impact semiclassical perturbation formalism. Obtained results have been used to investigate the regularities within spectral series. An example of the influence of Stark broadening on B IV lines in DO white dwarfs is given.Comment: 6 pages, 2 figure

    PERMANENT AND SOWN GRASSLANDS IN SERBIA: CURRENT STATE AND TRENDS

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    Number of cattle in Serbia during two decades of the 21st century shows the tendency of decreasing. The main source for sustainable livestock production in Serbia are grasslands. Permanent grasslands occupy approximately 30% of agricultural land in Serbia, thereby playing an important role in forage production and ecosystem services. The majority of natural meadows and pastures are located in hilly-mountainous regions. The general characteristics of grasslands in the central Balkans are low production and insufficient quality. The yield of permanent grasslands in Serbia is influenced very strongly by climatic conditions, type of grassland and level of organic and mineral fertilization. On areas that are not managed by mowing and fertilizing, forbs make up over half of the plant production.This paper presents some recent experiences and results in livestock feed production obtained from permanent and sown meadows and pastures in Serbia. There is survey of permanent grassland botanical composition and productivity with special emphasis on importance of preserving legume species. Also, recent trials assessed the benefits of mineral and organic fertilizers application in terms of forage production, testing whether the mineral or organic sources improves the stability of the grassland and evaluated response patterns over a large environmental gradient. Nutrient availability in permanent grasslands has a strong influence on plant species biodiversity, plant cover, and species’ dominance in the vegetation canopy. Dry matter yield is very low with high variation in crude protein content, which confirms that grasslands need to be maintained through fertilizer application, with special emphasis being given to the new role of manure enriched by zeolite. The above-stated lead to poor production potential of these grasslands for livestock production, nonetheless offering sustainable means of soil and biodiversity protection in the area

    Uticaj agroekoloških uslova i hibridne kombinacije na klijavost semena kukuruza

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    Germination energy and seed germination of four maize combinations cultivated under different growing conditions were observed. Analysis of hybrid seed of four commercial combinations derived at the Maize Research Institute, Zemun Polje, grown in three locations, were done on the working sample of 4 x 100 seeds under laboratory conditions. The experimental data was processed for the mean and total variability (X and C.V.) for both seed traits and for each test variant. The total average values of germination energy and germination in the period of investigation amounted to 94.5% and 94.8%, respectively. The coefficient of variation for germination energy was 0.67%, while for germination it was 0.39%. In the five-year study, the hybrid combination ZP704 had the highest values of germination energy (95.9%) and total germination (96.3%).Test results indicate that coefficients of variations for both observed traits over years were low, which points out to homogeneity of the material. Significant effects of factors (hybrid and location) and their interaction on observed seed properties were established by the analysis of variance. Gained results indicate that all four hybrids had high level of expression of traits under changeable agroecological conditions, as well as, a great effect of factors (hybrid and location) on germination energy and seed germination.U ovim istraživanja proučavane su energija klijanja i klijavost semena kukuruza četiri genotipske kombinacije u različitim agroekološkim uslovima uspevanja. Analize hirbidnog semena četiri komercijalne kombinacije Instituta za kukuruz Zemun Polje, proizvedene na tri lokaliteta, urađene su u laboratorijskim uslovima na radnom uzorku 4 x 100 semena. Eksperimentalni podaci obrađeni su na srednju vrednost i ukupnu varijabilnost (X i C.V.) za obe osobine semena i svaku varijantu istraživanja. Ukupna prosečna vrednost energije klijanja u posmatranom periodu bila je 94.5%, a klijavost 94.8%. Koeficijent varijacije za energiju iznosio je 0.67%, a za klijavost 0.39%. Hibridna kombinacija ZP704 u petogodišnjim istraživanjima imala je najviši nivo energije klijanja (95.9%) i ukupne klijavosti (96.3%). Rezultati testova ukazuju da koeficijenti varijacije ispitivanih karakteristika kod obe osobine su mali i ukazuju na homogenost materijala. Dvofaktorijalnom analizom varijanse utvrđen je značajan uticaj faktora (hibrid i lokacija), kao i njihova interakcija na ispitivane osobine semena. Dobijeni rezultati pokazali su da sva četiri hibrida imaju visok nivo ispoljavanja ispitivanih osobina u promenljivim agroekološkim uslovima, kao i visok uticaj faktora ( hibrid i lokalitet) na energiju i klijavost semena

    Discrimination of mineral waters using near-infrared spectroscopy and aquaphotomics

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    Voda je jedan od najčešće proučavanih materijala danas, ali uprkos tome mnoga njena svojstva i dalje ostaju nerazjašnjena i neiskorišćena. Voda je neophodna za normalno funkcionisanje ljudskog organizma, između ostalog zbog toga, poremećaji homeostaze vode u ljudskom telu leže u osnovi mnogih bolesti. Analiza vode i njene ispravnosti za upotrebu u ljudskoj ishrani uglavnom se bavi onim što je prisutno u vodi - koncentracijama prisutnih anjona i katjona, prisustvu mikroorganizama i tome slično. Različite vrste voda se uglavnom i klasifikuju upravo prema vrsti elemenata koje sadrže, koncentraciji prisutnih elemenata, ili pak odnosu između koncentracije pojedinih jona i njihov efekat na ljudski organizam razmatra se isključivo sa stanovišta elemenata koji su prisutni u njoj. Međutim, iako je poznato da voda formira različite tipove klastera i može da se organizuje oko prisutnih elemenata na različite načine, klasifikacija voda na osnovu organizacije vodenih molekula, kao i efekti različito klasterizovanih voda na ljudski organizam, za sada ne postoje u literaturi. Predmet ovog rada je diskriminacija različitih tipova voda na osnovu njihovog spektra u bliskoj infracrvenoj oblasti, primenom multivarijacione analize i novog pristupa za tumačenje spektara vode u ovoj oblasti, poznatog pod nazivom Akvafotomika. Akvafotomika interpretira spektar vode u bliskoj infracrvenoj oblasti preko posebno definisanih koordinata vodene mreže (water matrix coordinates - WAMACS) kojima su pripisani tačno određeni vibracioni modovi molekula vode preko kojih se može zaključiti kako se molekuli vode organizuju. Na taj način, primenom saznanja akvafotomike, voda se može opisati i sa aspekta njene organizacije u klastere, i time se omogućiti i diskriminacija voda na osnovu prisutnih tipova klastera što je prikazano u ovom radu.Despite that water is one of the most studied materials today its dynamic properties are still not well understood. Water state in human organism is of high importance for normal healthy functioning of human body. Different kinds of water are usually classified according to their present solutes and concentrations of these solutes, but though it is known that water molecules can form clusters around present solutes, the classification of waters based on types of water molecular organization and present clusters is not present in current literature. In this study the multivariate analysis is used for classification of commercial mineral waters based on their near-infrared spectra (NIR). Further, the aquaphotomics has been applied, a new approach for interpretation of near-infrared spectra of water, that gives insight into organization of water molecules in each of these waters

    Discrimination of mineral waters using near-infrared spectroscopy and aquaphotomics

    Get PDF
    Voda je jedan od najčešće proučavanih materijala danas, ali uprkos tome mnoga njena svojstva i dalje ostaju nerazjašnjena i neiskorišćena. Voda je neophodna za normalno funkcionisanje ljudskog organizma, između ostalog zbog toga, poremećaji homeostaze vode u ljudskom telu leže u osnovi mnogih bolesti. Analiza vode i njene ispravnosti za upotrebu u ljudskoj ishrani uglavnom se bavi onim što je prisutno u vodi - koncentracijama prisutnih anjona i katjona, prisustvu mikroorganizama i tome slično. Različite vrste voda se uglavnom i klasifikuju upravo prema vrsti elemenata koje sadrže, koncentraciji prisutnih elemenata, ili pak odnosu između koncentracije pojedinih jona i njihov efekat na ljudski organizam razmatra se isključivo sa stanovišta elemenata koji su prisutni u njoj. Međutim, iako je poznato da voda formira različite tipove klastera i može da se organizuje oko prisutnih elemenata na različite načine, klasifikacija voda na osnovu organizacije vodenih molekula, kao i efekti različito klasterizovanih voda na ljudski organizam, za sada ne postoje u literaturi. Predmet ovog rada je diskriminacija različitih tipova voda na osnovu njihovog spektra u bliskoj infracrvenoj oblasti, primenom multivarijacione analize i novog pristupa za tumačenje spektara vode u ovoj oblasti, poznatog pod nazivom Akvafotomika. Akvafotomika interpretira spektar vode u bliskoj infracrvenoj oblasti preko posebno definisanih koordinata vodene mreže (water matrix coordinates - WAMACS) kojima su pripisani tačno određeni vibracioni modovi molekula vode preko kojih se može zaključiti kako se molekuli vode organizuju. Na taj način, primenom saznanja akvafotomike, voda se može opisati i sa aspekta njene organizacije u klastere, i time se omogućiti i diskriminacija voda na osnovu prisutnih tipova klastera što je prikazano u ovom radu.Despite that water is one of the most studied materials today its dynamic properties are still not well understood. Water state in human organism is of high importance for normal healthy functioning of human body. Different kinds of water are usually classified according to their present solutes and concentrations of these solutes, but though it is known that water molecules can form clusters around present solutes, the classification of waters based on types of water molecular organization and present clusters is not present in current literature. In this study the multivariate analysis is used for classification of commercial mineral waters based on their near-infrared spectra (NIR). Further, the aquaphotomics has been applied, a new approach for interpretation of near-infrared spectra of water, that gives insight into organization of water molecules in each of these waters
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