223 research outputs found

    Influence of nutrition on productivity and chemical composition of khorasan wheat-triticum turgidum l. Ssp. turanicum jakubz

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    Khorasan wheat (Triticum turgidum L. ssp. turanicum Jakubz.) the white awn population is the optional type of a high-energy grain. This study aimed to examine the influence of plants’ mineral nutrition on the chemical composition of Khorasan grain. The mineral diet used in the supplementary plant nutrition affected the total amount of dry matter and the chemical composition of wheat grains, increasing its nutritional value. At the time of harvest, Khorasan wheat grains contained 89.74% of dry matter, i.e. 10.26% of water, while in the variants with additional nutrition had less dry matter 86.90% and more water, 13.10%, which indicates an extension of the vegetation period of plants in conditions of enhanced mineral nutrition. Mineral nutrition, which primarily increased the amount of nitrogen, statistically significantly affected protein synthesis in plants. Khorasan wheat grains had 14.94% of total proteins in the control and 15.2% in variants with NPP nutrition. Plant nutrition did not have a greater impact on the synthesis of oils in the grains, starch, NFE, and mineral salts content. The supplementary nutrition affected the total amount of dry matter and chemical composition of wheat grain increasing its nutritional value

    CMB anisotropies seen by an off-center observer in a spherically symmetric inhomogeneous universe

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    The current authors have previously shown that inhomogeneous, but spherically symmetric universe models containing only matter can yield a very good fit to the SNIa data and the position of the first CMB peak. In this work we examine how far away from the center of inhomogeneity the observer can be located in these models and still fit the data well. Furthermore, we investigate whether such an off-center location can explain the observed alignment of the lowest multipoles of the CMB map. We find that the observer has to be located within a radius of 15 Mpc from the center for the induced dipole to be less than that observed by the COBE satellite. But for such small displacements from the center, the induced quadru- and octopoles turn out to be insufficiently large to explain the alignment.Comment: 8 pages (REVTeX4), 7 figures; v2: minor changes, matches published versio

    Unaprijeđeno upravljanje momentom visokobrzinskog pogona s asinkronim motorom bez mjerenja brzine

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    This paper presents improved torque control scheme for a high speed sensorless induction motor drive. The proposed high speed torque control scheme substitutes the flux oriented control by the voltage angle control in the flux weakening regime. This scheme uses maximum of available inverter voltage, alleviates well known problems of current control schemes in conditions with insufficient voltage margin and avoids the influence of estimated speed error to the achieved flux level. The algorithm uses similar slip control as flux oriented control algorithm, but is applied without an outer flux trajectory reference which is typical for the flux weakening, providing a fast and well damped torque response even if error in estimated speed is present. Experiments confirm the effectiveness of proposed torque control algorithm, smooth transition from the flux oriented control in the base speed region to the voltage angle control in the flux weakening, superior dynamic performance of the voltage angle torque control, and its robustness to an estimated rotor speed error.U radu je predstavljena unaprijeđena shema upravljanja za pogon visokobrzinskog asinkronog motora bez mjerenja brzine. Predloženi postupak zamjenjuje vektorsko upravljanje upravljačkom strukturom s upravljanjem kutom napona u slabljenju polja. Predložena shema koristi maksimalni raspoloživi napon invertora, eliminira dobro poznate probleme strujno reguliranih pogona u uvjetima s nedovoljnom rezervom napona i eliminira utjecaj greške u estimaciji brzine na dostignutu razinu toka. Algoritam koristi sličnu kontrolu klizanja kao i vektorsko upravljanje, ali bez tipičnog vanjskog zadavanja toka u slabljenju polja, pružajući brz i dobro prigušen odziv momenta čak i u slučaju greške u estimaciji brzine. Eksperimenti izvedeni na velikoj brzini vrtnje potvrđuju učinkovitost predložene regulacije momenta, gladak prijelaz iz baznog područja brzine u slabljenje polja, vrhunske dinamičke performanse upravljanja kutom napona i robusnost na pogrešku u estimiranoj brzini vrtnje

    Effect of temperature on the physical changes and drying kinetics in plum (Prunus domestica L.) Požegača variety

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    In this study, drying kinetics of autochthonous variety Požegača plum was examined in a laboratory dryer at three temperatures. The whole plum fruits, together with the kernels were subjected to the drying process. The effect of drying has been examined at temperatures of 55, 60 and 75 °C, with a constant air velocity of 1.1 m s-1. The corresponding experimental results were tested using six nonlinear regression models. Coefficient of determination (R2), standard regression error (SSE), model correlation coeficient (Vy), as well as the maximum absolute error (ΔY) showed that the logaritmic model was in good agreement with the experimental data obtained. During drying of plums, the effective diffusivity was found to be between 5.6×10-9 for 55 °C and 8.9×10-9 m2 s-1 at 75 °C, respectively. The physical characteristics of fresh (length 39.64 mm and width 29.15 mm) and dried (length 37.52 mm and width 22.85 mm) plum fruit were determined. Finally, by chemical analysis, the contents of micro- and macro-elements (Fe, Mn, Cu, B and N, F, K, Ca, Mg and S) in the skin and flesh of the dried product, prunes, has been established

    An Imprint of Super-Structures on the Microwave Background due to the Integrated Sachs-Wolfe Effect

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    We measure hot and cold spots on the microwave background associated with supercluster and supervoid structures identified in the Sloan Digital Sky Survey Luminous Red Galaxy catalog. The structures give a compelling visual imprint, with a mean temperature deviation of 9.6 +/- 2.2 microK, i.e. above 4 sigma. We interpret this as a detection of the late-time Integrated Sachs-Wolfe (ISW) effect, in which cosmic acceleration from dark energy causes gravitational potentials to decay, heating or cooling photons passing through density crests or troughs. In a flat universe, the linear ISW effect is a direct signal of dark energy.Comment: 4 pages, 2 figures, accepted to ApJ Letters. Minor changes to match accepted versio

    MULTI-CRITERIA SELECTION OF STANDARDS FOR SYSTEM ANALYST ACTIVITIES IN ORGANIZATIONS

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    The paper defines the methodology for the selection of standards and tools that system analysts use for the purposes of analyzing the computer infrastructure of organizations. The goal of system analyst analysis is primarily to increase: the speed of processing information, the efficiency of data processing and data exchange. A large number of standards and tools complicates an adequate choice, and on the other hand system analysts are not the only ones who influence the choice. In the analysis of the choice of standards and tools, in the second chapter an algorithm for determining the weight coefficients for the criteria selected by the company and the ranking of the standards for selection is presented through an example. In order to choose the best standard, the choice was made between four standards described in the third chapter. The chapter defines the criteria that cover IT activities for the selection of standards according to selected criteria and defined weight coefficients in the observed company. Finally, on the assumption that the company together with the analyst chose “k” criteria, where the methodology (LBWA) for the selection of weight coefficients for the criteria was proposed, a new model for calculating the ranking of standards was presented, i.e. the choice of the best. The conclusion of the paper is that the presented procedure for choosing standards is not complicated, that it is very successful, and that in this way the proposals were more easily accepted and implemented in the fastest way

    Comparative study of W(VI) and Cr(VI) oxyanions binding ability with magnetic polymer nanocomposite

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    Magnetite particles are widely used as sorbents for removal of heavy metal ions, organic dyes, drug delivery, cell labelling, magnetic resonance imaging, sensing, etc. [1,2]. Also, the functionalization of polymer by specific ligands enables customizing these composites for specific applications. Magnetic crosslinked macroporous copolymer of glycidyl methacrylate, GMA, and ethylene glycol dimethacrylate, EGDMA, mPGME was synthesized by suspension copolymerisation of GMA and EGDMA, in the presence of inert component (mixture of cyclohexanol and aliphatic alcohol) [3] and magnetite nanoparticles coated with (3-aminopropyl)trimethoxysilane (APTMS) as silanization agent. The sample was additionally functionalized with diethylene triamine mPGME-deta. Magnetic amino-functionalized copolymer was fully characterized in terms of its structural and magnetic properties using: FTIR analysis, SEM/EDX, XRD and SQUID magnetometry. Synthesized magnetic macroporous copolymer mPGME-deta was tested as sorbent of W(VI) and Cr(VI) oxyanions from diluted aqueous solutions (Ci=25 ppm) in a batch system, under uncompetitive conditions, at room temperature (T=25 °C). The oxyanions concentrations in solution after 60 min of sorption, were determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES). The maximal experimental values of oxyanions sorption capacities (Qmax μmol/g) were compared with theoretically values determined by theoretical modeling, using quantum-chemical methods: Density Functional Theory (DFT), statistic analysis of the crystal structure extracted from the Cambridge Structural Database (CSD) and by implicit solvation model (SMD). It was found that the process is spontaneous and exothermic, and that the active sites of magnetic copolymer sorbent are amino groups (of diethylenetriamine and APTMS) which forms electrostatic interactions with oxianions W(VI) and Cr(VI)

    Antifungalna aktivnost ekstrakata makrogljiva na fitopatogene sojeve gljiva rodova Fusarium sp. i Alternaria sp.

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    During the last decades, intensive application of synthetic fungicides in the agricultural crop protection practice caused growing concern for the existence of toxic chemical residues in food as well as in the whole environment. Instead of using synthetic fungicides, it is suggested that crop protection be carried out by using preparations based on compounds of natural origin (secondary metabolites of plants or microorganisms, including macrofungi from Basidiomycota) as biological control agents. The potential of macrofungal species as biocontrol agents was analyzed in this investigation of eight autochthonous species from different locations in Serbia. Both the terricolous species: Coprinus comatus, Coprinellus truncorum, Amanita strobiliformis, Hydnum repandum and the lignicolous species: Flammulina velutipes, Stereum subtomentosum, Trametes versicolor and Bjerkandera adusta were examined, with an aim to detect some novel sources of antifungal agents. This study surveyed antifungal activity of selected macrofungal extracts (MeOH, EtOH and CHCl3) against phytopathogenic Fusarium and Alternaria strains isolated from garlic, soybean and rice: F. proliferatum, F. verticillioides, F. proliferatum, F. graminearum and A. padwickii. Microdilution method in 96 well micro-plates was applied for the estimation of antifungal effects of macrofungi extracts in the range from 24.75 to 198.00 mg/ml and determination of minimal inhibitory (MIC) and minimal fungicidal concentration (MFC). EtOH extract of mychorhizal species H. repandum showed antifungal activity against all analyzed phytopathogenic strains, with the strongest effect on Fusarium strains (MIC 24.75 mg/ml; MFC 24.75 mg/ml). Among others, MeOH extracts of S. subtomentosum and C. micaceus showed similar effects while only B. adusta showed slight effect on Fusarium strains (MIC 24.75-99.00 mg/ml; MFC 24.75-99.00 mg/ml) and none effect on A. padwickii. The obtained results indicate the possibility of using examined extracts as efficient antifungal agents and provide the basis for the new formulations of biocontrol agents against phytopathogenic fungi in the future.Tokom poslednjih decenija intezivna primena sintetičkih fungicida u zaštiti poljoprivrednih useva izaziva sve veću zabrinutost ljudi zbog prisustva toksičnih hemijskih ostataka u prehrambenim proizvodima kao i celoj okolini. Umesto korišćenja sintetičkih fungicida, preporučuje se da se zaštita useva vrši korišćenjem preparata na bazi jedinjenja prirodnog porekla (sekundarni metaboliti biljaka ili mikroorganizama uključujući i makrogljive iz razdela Basidiomycota) kao agense biološke kontrole. U ovom radu istraživan je potencijal agenasa biološke kontrole za osam autohtonih vrsta makrogljiva s različitih lokaliteta u Srbiji. Obe, terikolne vrste: Coprinus comatus, Coprinellus truncorum, Amanita strobiliformis, Hydnum repandum i lignikolne vrste: Flammulina velutipes, Stereum subtomentosum, Trametes versicolor i Bjerkandera adusta su istražene s ciljem da se otkriju neki novi izvori antifungalnih agenasa. U okviru ovog rada istražena je antifungalna aktivnost odabranih ekstrakata makrogljiva (metanolni, etanolni i hloroformski) protiv fitopatogenih sojeva Fusarium i Alternaria izolovanih s belog luka, soje i pirinča: F. proliferatum, F. verticillioides, F. proliferatum, F. graminearum i A. padwickii. Za procenu antifungalnog efekta ekstrakata makrogljiva upotrebljena je mikrodiluciona metoda mikrotitar pločama s 96 velova u opsegu koncentracija od 24,75 do 198,00 mg/ml i determinaciju minimalne inhibitorne (MIC) i minimalne fungicidne koncentracije (MFC). Etanolni ekstrakt mikorizne vrste H. repandum pokazao je atifungalnu aktivnost prema svim analiziranim fitopatogenim sojevima, sa najjačim efektom prema sojevima Fusarium (MIC 24,75 mg/ml; MFC 24,75 mg/ml). Između ostalog, sličan efekat pokazali su i metanolni ekstrakti S. subtomentosum i C. micaceus, dok je samo B. adusta imala blagi efekat na sojeve Fusarium (MIC 24,75-99,00 mg/ml; MFC 24,75-99,00 mg/ml), ali ne i na A. padwickii. Dobijeni rezultati ukazuju na mogućnost korišćenja ispitanih ekstrakata kao veoma efikasnih antifungalnih agenasa i samim tim oni predstavljaju osnovu za nove formulacije biokontrolnih agenasa protiv fitopatogenih gljiva u budućnosti

    Refractive-index sensing with ultra-thin plasmonic nanotubes

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    We study the refractive-index sensing properties of plasmonic nanotubes with a dielectric core and ultra-thin metal shell. The few-nm thin metal shell is described by both the usual Drude model and the nonlocal hydrodynamic model to investigate the effects of nonlocality. We derive an analytical expression for the extinction cross section and show how sensing of the refractive index of the surrounding medium and the figure-of-merit are affected by the shape and size of the nanotubes. Comparison with other localized surface plasmon resonance sensors reveals that the nanotube exhibits superior sensitivity and comparable figure-of-merit

    The supernova Hubble diagram for off-center observers in a spherically symmetric inhomogeneous universe

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    We have previously shown that spherically symmetric, inhomogeneous universe models can explain both the supernova data and the location of the first peak in the CMB spectrum without resorting to dark energy. In this work, we investigate whether it is possible to get an even better fit to the supernova data by allowing the observer to be positioned away from the origin in the spherically symmetric coordinate system. In such a scenario, the observer sees an anisotropic relation between redshifts and the luminosity distances of supernovae. The level of anisotropy allowed by the data will then constrain how far away from the origin the observer can be located, and possibly even allow for a better fit. Our analysis shows that the fit is indeed improved, but not by a significant amount. Furthermore, it shows that the supernova data do not place a rigorous constraint on how far off-center the observer can be located.Comment: 7 pages (REVTeX4), 5 figure
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