41 research outputs found

    Influence of vine loads with fertile buds on grape yield and quality of variety ŽiŽak in podgorica vineyard area

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    Results of a two-year study of the influence of different vine loads with fertile buds on elements of grape yield and quality of Žižak grape variety are presented in this paper. The research was conducted in the Podgorica sub region, at the Lješkopolje site. Four different vine loads with fertile buds were applied: 14 buds, 18 buds, 20 and 24 buds per vine. The results of this research show that the applied loads significantly influence the examined parameters of the autochthonous variety Žižak. The highest percentage of developed and fertile shoots, as well as the average number of flowers per bud, had a variant with load of 14 buds. The relative coefficient of yielding in all examined load variants had mean values. In terms of the number of flowers per fertile shoot in the two-year average, variants with a load of 18 and 14 buds (1.44 and 1.39) stood out. The highest yield of grapes in the two-year average had the variant with a load of 24 buds-3.60 kg/vine, while the highest bunch weight had the variant V1-185 g. The quality of grapes also varied significantly under the influence of the vine load with fertile buds. The highest sugar content in must had variant with a load of 18 buds (22.32%), while the highest acid content (6.27g/l) was recorded in the variant with 24 buds per vine

    Crystallization behaviour of multicomponent germanate glasses

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    Predmet ove doktorske disertacije je ispitivanje kristalizacionog ponašanja germanatnih i germanatnofosfatnih stakala iz sistema K2O-Nb2O5-GeO2 i Li2O-Al2O3- GeO2-P2O5. Na osnovu preliminarnih ispitivanja za proučavanje su izabrana stakla sastava: 30K2O·34Nb2O5·36GeO2 (mol%) i 22,5Li2O·10Al2O3·30GeO2·37,5P2O5 (mol%). Kristalizacione osobine ispitane su pri izotermskim i neizotermskim uslovima kristalizacije. Dobijeni rezultati pokazuju da trokomponentno germanatno staklo kristališe primarnom kristalizacijom, pri čemu fazni sastav kristalisanog uzorka kao i nastajanje pojedinih kristalnih faza zavise od temperature kristalizacije. Na temperaturama kristalizacije < 800 °C kao primarna faza javlja se K3.8Nb5Ge3O20.4, a kao sekundarne faze javljaju se K4Nb6O17 i K6Nb6Ge4O26. Na temperaturama kristalizacije > 800 °C kao primarna faza javlja se K6Nb6Ge4O26, a kao sekundarne faze javljaju se: K3.8Nb5Ge3O20.4, K10Nb22Ge4O68 i KNbO3 faza. Dimenzije kristalita su 20-100 nm. U slučaju četvorokomponentnog germanatnofosfatnog stakla utvrñena je primarna kristalizacija LiGe2[PO4]3 faze sa dimenzijama kristalita 30-500 nm. Odreñen je uticaj granulacije praha stakla na mehanizam kristalizacije i fazni sastav kristalisanih uzoraka. U slučaju kompaktnih uzoraka stakla konstatovan je zapremiski mehanizam kristalizacije sa sferulitskom morfologijom rasta kristala kod oba sastava. Ispitan je proces nukleacije i odreñena je temperaturna i vremenska zavisnost brzine nukleacije. Brzine nukleacije ovih stakala su u oblasti 1,77·1014 - 7,34·1016 m-3s-1 . Odreñena je temperaturna zavisnost brzina rasta kristala i energije aktivacije koje iznose od 294 kJ/mol do 1150 kJ/mol u zavisnosti od faze koja se formira. Odreñene su oblasti nukleacije i rasta kristala, temperature maksimalne brzine nukleacije i procenjene temperature maksimalne brzine rasta kristala. Konstatovano je preklapanje oblasti nukleacije i rasta kristala kod oba sastava. U ispitivanjima su korišćene metode atomske apsorpcione (emisione) spektrometrije (AAS), spektrofotometrije, dilatometrije, diferencijalno-termijske analize (DTA), diferencijalno-skenirajuće kalorimetrije (DSC), infracrvene spektroskopije (FT-IC), rendgenske difrakcione (XRD) i skenirajuće elektronsko mikroskopske (SEM) analize...The subject of this thesis is the study of the crystallization behavior of germanate and germano-phosphate glasses from the systems K2O-Nb2O5-GeO2 and Li2O-Al2O3-GeO2- P2O5. Based on preliminary experiments the glasses of composition 30K2O·34Nb2O5·36GeO2 (mol%) and 22,5Li2O·10Al2O3·30GeO2·37,5P2O5 (mol%) were selected for examination. The crystallization properties were examined under isothermal and non-isothermal crystallization conditions. Three-component germanate glass crystallize by primary crystallization while the phase composition of crystallized sample and formation of the crystalline phases depends on temperature of crystallization. At crystallization temperatures < 800°C as the primary phase K3.8Nb5Ge3O20.4, appeared and as seconday ones are K4Nb6O17 and K6Nb6Ge4O26. For T > 800 °C, the K6Nb6Ge4O26 appeared as primary phase and as secondary ones are K3.8Nb5Ge3O20.4, K10Nb22Ge4O68 and KNbO3. In the case of four-component germano-phosphate glass the primary crystallization of LiGe2[PO4]3 phase with crystallites dimension of 30-500 nm was detected. The effect of the grain size of glass powders on crystallization mechanism and phase composition of the crystallized samples was determined. For both glass compositions the volume crystallization mechanism with a spherulitic growth morphology of crystals was determined on compact glass samples. The nucleation process was studied and the temperature and time dependencies of nucleation rate were defined. The nucleation rate of these glasses are in the range 1,77·1014 - 7,34×1016 m-3s-1 . Also, the temperature dependence of crystal growth rate was determined and the activation energies calculated are 294 - 1150 kJ/mol depending on the phase formed. The temperature ranges of nucleation and crystal growth and the temperature of maximal nucleation rate and the temperatures of maximal crystal growth rates were determined. For both glass compositions, an overlapping of nucleation and crystal growth range was noted. The methods employed for investigation are: atomic absorption spectroscopy (AAS), spectrophotometry, dilatometry, differential thermal analysis (DTA), differential scanning calorimetry (DSC), infra reed spectroscopy (FTIR), X- ray diffraction (XRD) and scanning electron microscopy (SEM)..

    Uticaj vrste klona prokupca i postupka vinifikacije na sadržaj rezveratrola u vinu

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    The focus of this study was to investigate the effects of clones (subvarieties) of autochthonous Serbian grape variety Prokupac, along with the influence of vinification method on the content of transand cis-resveratrol as well as on total phenolic content (TPC) in wines. Wines were made from four clones of Prokupac variety (PR1, 40/1, PR6 and PR7) by application of different periods of maceration duration (1, 5 and 10 days). The effects of different species of selected wine yeasts and glucosidase enzymes on the quantity of resveratrol and TPC in wine made from PR6 variety were also investigated. The content of trans-resveratrol varied from 0.27 mg/L to 1.46 mg/L. The highest content of resveratrol was determined in Prokupac clone PR6, and the lowest in PR7 clone. An increase in resveratrol and TPC content was observed in all clones when the duration of maceration was prolonged. Wine produced by application of b enzyme preparation and 299 yeast had the highest concentration of total resveratrol (4.23 mg/L). The TPC was the highest in the wine made by combined application of yeast 299 and OE enzyme. The obtained results showed that by adequate selection of varieties, prolonged duration of maceration, application of appropriate species of yeast and enzyme preparations, it is possible to increase the content of resveratrol and other phenolic compounds in wine.Cilj ovog istraživanja bio je da se ispita uticaj različitih klonova autohtone srpske sorte Prokupac kao i postupak vinifikacije na sadržaj transi cisrezveratrola i sadržaj ukupnih polifenola (SUP) u vinima. Vina su proizvedena od četiri klona sorte Prokupac (PR1, 40/1, PR6 i PR7) primenom različitih dužina trajanja maceracije (1, 5 i 10 dana) za svaki klon. Takođe je ispitivan uticaj različitih izabranih kvasaca i enzimskih preparata glikozidaza na sadržaj rezveratrola i SUP u vinima proizvedenim od klona PR6. Sadržaj transi cisrezveratrola je određen HPLC metodom sa UV detektorom uz prethodnu tečno čvrstu ekstrakciju (SPE). Određivanje SUP je urađeno metodom po FolinČokalteu. Sadržaj transrezveratrola je bio od 0,27 mg/L do 1,46 mg/L. Najviši sadržaj rezveratrola je bio u klonu PR6 dok je najniži PR7. Povećanje sadržaja rezveratrola i SUP je primećeno kod svih klonova kada je maceracija duže trajala. Vino proizvedeno primenom enzimskog preparata glikozidaza b i kvasca 299 je imalo najviši sadržaj ukupnog rezvertrola (4,23 mg/L). Najviši SUP je bio u vinima proizvedenim primenom enzimskog preparata glikozidaza OE i kvasca 299. Dobijeni rezultati ukazuju da je izborom odgovarajućeg klona, dužine maceracije, primene odgovarajućeg kvasca i enzimskog preparata moguće povećati sadržaj rezveratrola i drugih fenolnih jedinjenja u vinu

    Antibacterial potential of electrochemically exfoliated graphene sheets

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    Electrochemically exfoliated graphene is functionalized graphene with potential application in biomedicine. Two most relevant biological features of this material are its electrical conductivity and excellent water dispersibility. In this study we have tried to establish the correlation between graphene structure and its antibacterial properties. The exfoliation process was performed in a two electrode-highly oriented pyrolytic graphite electrochemical cell. Solution of ammonium persulfate was used as an electrolyte. Exfoliated graphene sheets were dispersed in aqueous media and characterized by atomic force microscopy, scanning electron microscopy, Raman spectroscopy, Fourier transform infrared spectroscopy, X photoelectron spectroscopy, X-ray diffraction, electron paramagnetic resonance, zeta potential, contact angle measurements and surface energy. Antibacterial assays have shown lack of the significant antibacterial activity. Major effect on bacteria was slight change of bacteria morphology. Membrane remained intact despite significant change of chemical content of membrane components.This is the peer reviewed version of the paper: Marković, Z. M., Matijašević, D. M., Pavlović, V. B., Jovanović, S. P., Holclajtner-Antunović, I. D., Špitalský, Z., Mičušik, M., Dramićanin, M. D., Milivojević, D. D., Nikšić, M. P., & Todorović Marković, B. M. (2017). Antibacterial potential of electrochemically exfoliated graphene sheets. Journal of Colloid and Interface Science, 500, 30–43. [https://doi.org/10.1016/j.jcis.2017.03.110][https://www.sciencedirect.com/science/article/abs/pii/S0021979717303776?via%3Dihub

    The crystal growth of NASICON phase from the lithium germanium phosphate glass

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    The crystal growth rate of LiGe2(PO4)3 phase from lithium germanium-phosphate glass was studied. The glass have been homogenized using the previously established temperature-time conditions, which make it possible to remove volatile substances from the glass melt. The atomic absorption spectrophotometry (AAS) was used to determine the chemical content of the obtained glass and scanning electron microscope (SEM) were used to reveal the isothermal process of crystal growth. The crystal growth rates were determined experimentally and theoretically

    The analysis of the crystal growth process of the lithium germanium phosphate glass : [invited presentation]

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    The crystal growth rate of lithium germanium-phosphate glass was studied. The glasses have been homogenized using the previously established temperature-time conditions, which make it possible to remove a volatile substances from the glass melt. The AAS was used to determine the chemical content of obtained glass, the differential thermal analysis (DTA), and scanning electron microscope (SEM) were used to reveal the isothermal process of crystal growth, respectively. It has been found that the experimental determined crystal growth rate has a tendency toward of exponentially increase with an increase the temperature

    Implementation of climate change science in viticulture sustainable development planning in Serbia

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    Growing interest in Serbia in adaptation of viticulture to climate change emerged from a recorded positive impact of summer increased draught on domestic wine quality. Another motivation is that viticulture has been recognized as one of the fastest developing agricultural sectors in Serbia and, to contain its growing potential, it is crucial to provide basis for its future sustainable development. Prioritization and implementation of adaptation measures in practice require reliable assessment of climate projections. For climate change impact assessment is used high resolution multi-model ensemble of nine regional climate models simulations, bias corrected, with two most probable future scenarios of GHG emissions RCP4.5 and RCP8.5, for the period 2016-2100. Analysis has been done for the near future, mid-century and end of the century periods. The periods are defined according to the IPCC 5th Assessment Report, which enables comparison of climate change impacts with a wider region, and preferably motivate future international collaboration and knowledge exchange

    REACTION OF TABLE GRAPE VARIETIES TO LOW WINTER TEMPERATURES

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    The aim ofthis study was toinvestigate theresistanceof winter buds to lowwinter temperatures oneighttablevarieties of differentripening time. The study was conducted during vine dormancy at three testing dates during winter i.e. over the last ten days of the three winter months of December, January and February. At the first, second and third dates, the air temperature in the freezing chamber was reduced to - 15oC, -20oC, and -10oC, respectively.The analysis of the average values for the study period shows that Muscat Hamburg and Smederevo Muscat had the lowest and highest average percentage of completely frozen buds (48.97% and 58.84%, respectively). The average values for partly frozen buds ranged from 29.17 % in Afuz-Ali to 33.11 % in Muscat Hamburg. The evaluation of the data on unfrozen buds suggests that the average values were within the range of 11.15 % (Smederevo Muscat) to 17.91 % (Muscat Hamburg)

    The nucleation of K2O center dot TiO2 center dot 3GeO(2) glass under non-isothermal conditions

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    The nucleation of germanate K2O center dot TiO2 center dot 3GeO(2) glass under non-isothermal conditions was studied by the DTA method. The temperature ranges of nucleation and crystal growth of this glass partly overlap. The influence of the mass of the glass sample as well as, the time and temperature of the pre-DTA heat treatment on the DTA parameters T-p, (delta T)(p), and Delta T-p was investigated. A complex behavior of these parameters was evidenced. It was shown that for fixed temperatures, increasing the annealing time of the pre-DTA heat treatment resulted in a decrease in the temperature of the DTA peak (T-p). The curve of the dependence of DTA peak heights (delta T)(p) on time showed a maximum and the parameter Delta T-p continually increased with increasing time. The influence of the temperature of the pre-DTA heat treatment on the DTA parameters showed that for annealing times t gt t(ind), the dependences of T-p(-1) and Delta T-p vs. T corresponded to the dependence of Ion Tin the case when the regions of I and U partly overlapped. As shown, in this case. the change of (delta T)(p) vs. T is not convenient for an analysis of the nucleation behavior of the glass
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