Analiza ekonomskih pokazatelja u primeni GPS tehnologije u Poljoprivrednom kombinatu Beograd

This paper examined the level of savings in the application of modern technical systems for satellite guidance and control over performing agricultural operations throughout the season. The exemplary property was Agricultural Corporation Belgrade (PKB), which covers about 21.000 hectares of arable land. The effects of plot shape and direction of movement of tractor-attachment units in calculating the savings from reduced overlapping of adjacent passes were studied. The analysis was carried out of savings per crop (maize, wheat, soybean, sugar beet and alfalfa) and the operations for each crop separately, based on the manufacturing technology applied to an exemplary property. Detailed data are shown only for maize. Comparing the achieved level of savings, the application of guidance for the type of the most economically viable operations was found as well as the needed equipment level of guidance devices and management. In particular, the analysis involved the functional dependence of the economic savings in fuel and inputs for the operations such as mineral fertilizers distribution and chemical plant protection. Tabulated are the data estimates for the degree of anticipated savings for operations related to the five analyzed crops.U ovom radu ispitan je stepen ušteda pri primeni najsavremenijih tehničkih sistema za satelitsko navođenje i automatsko upravljanje pri obavljanju poljoprivrednih operacija tokom cele sezone. Uzorno imanje bila je Poljoprivredna korporacija Beograd koja se prostire na oko 21.000 hektara obradive površine. Analiziran je uticaj oblika parcele i pravca kretanja agregata traktor-priključna mašina pri kalkulisanju ušteda usled smanjenja preklopa susednih prohoda. Izvršena je analiza ušteda po kulturama (kukuruz, pšenica, soja, šećerna repa i detelina) i po operacijama za svaku kulturu pojedinačno, prema tehnologiji proizvodnje primenjenoj na uzornom imanju. Detaljno su prikazani podaci samo za kukuruz. Poređenjem ostvarenih stepena uštede zaključeno je pri kojim operacijama je primena navođenja ekonomski najopravdanija i koliki nivo opremljenosti uređajima za navođenje i upravljanje je potreban. Posebno je analizirana funkcionalna zavisnost ekonomskih ušteda u gorivu i inputima za operacije distribucije mineralnog hraniva i hemijske zaštite biljaka. Tabelarno je data procena stepena svih očekivanih ušteda za operacije koje se odnose na pet analiziranih kultura

Formaldehyde in screen printing indoor

The presence of formaldehyde in air samples has been detected in five screen printing facilities in Novi Sad, Serbia. Air samples were sampled continuously during 4 hours, and concentration levels of formaldehyde was determined by UV-VIS spectrometry at 580 nm. The range of formaldehyde concentrations was from 0.413 to 0.836 ppm. Comparison of the detected concentration levels with the permissible exposure limit of 0.75 ppm (the OSHA standard) indicated that the formaldehyde concentration in facility 5 was 1.11 times higher than prescribed value

Source of lead in Central American and Caribbean mineralization, II. Lead isotope provinces

In an earlier study of Mesozoic and Cenozoic mineralization in Central America and the Caribbean region, we found that lead isotopic compositions of deposits in northern Central America, which is underlain by a pre-Mesozoic craton, ranged to higher 206Pb/204Pb and 207Pb/204Pb compositions than did deposits from elsewhere in the region, where the basement is Mesozoic oceanic material. Using 16 analyses for 12 new deposits, as well as new analyses for 11 of the samples studied previously, we have found that lead isotopic compositions correlate closely with crustal type but show little or no correlation with depth to the M-discontinuity. The deposits are divisible into three main groups including (in order of increasing 207Pb/204Pb and 208Pb/204Pb ratio): (1) deposits in southern Central America and all deposits in the Greater Antilles except Cuba; (2) all deposits in northern Central America; and (3) the Cuban deposits. Southern Central American and Caribbean lead is higher in 207Pb/204Pb and 208Pb/204Pb than most mid-ocean ridge basalts but could have been derived directly or indirectly from undepleted mantle. Northern Central America can be divided into the Maya block, which belongs to the Americas plate, and the Chortis block, which belongs to the Caribbean plate. Maya block deposits fall along a linear array whereas those of the Chortis block (except the Monte Cristo deposit) form a cluster. These results suggest that the Maya block is underlain by crust or mantle with a large range of U/Pb and Th/U ratios, whereas the Chortis block basement is more homogeneous. Two-stage model calculations indicate an age of about 2280+/-310 m.y. for the Maya block basement, although no such rocks are known in the region. Comparison of the Chortis block data to our recently published lead isotopic analyses of Mexican deposits shows considerable similarities suggesting that the Chortis block could have been derived from Mexico.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24169/1/0000428.pd

ANALYSIS OF BREAKING CHARACTERISTICS OF COTTON FABRICS OF THE MOST FREQUENT WEAVES

The behavior of three raw cotton fabrics of different basic weaves and approximate yarn settings and yarn counts, when subjected to tensile deformation, is described in this article. The values of the breaking force in the fabric in the linen weave have the highest mean numerical value, while the cotton fabric in the atlas weave has the lowest values. The fabric in the twill weave has the highest values for elongation at break, while the lowest values are present in the fabric in the atlas weave. The fabric in linen weave is the most resistant to external deformations, while the fabric in twill and atlas weaves are the weakest. The standard deviation and coefficient of variation for fabrics in all weaves have values that move within a range that confirms the validity of the results. In some cases, larger variations of these statistical data mean that these results can be taken with a certain amount of caution. It seems that there are a lot of latent stresses in the fabric, which are relaxed during the action of the tearing force, causing greater variations in the measurement results. Deformation curves after nonlinear fitting of the breaking force-elongation at break dependence are described by polynomial equations of the fourth and fifth degree, with the fact that about 99% of the variability of the dependent variable can be explained by means of the analyzed independent variables. Polynomial models are practically usable because they can predict with high reliability the deformation behavior of fabrics with similar weaves in the direction of the warp. There are statistically significant correlations between numerous values for breaking force from the experiment and the polynomial model

Product of Three Random Variables and its Application in Relay Telecommunication Systems in the Presence of Multipath Fading, Journal of Telecommunications and Information Technology, 2019, nr 1

In this paper, the product of three random variables (RVs) will be considered. Distribution of the product of independent random variables is very important in many applied problems, including wireless relay telecommunication systems. A few of such products of three random variables are observed in this work: the level crossing rate (LCR) of the product of a Nakagami-m random variable, a Rician random variable and a Rayleigh random variable, and of the products of two Rician RVs and one Nakagami-m RV is calculated in closed forms and presented graphically. The LCR formula may be later used for derivation of average fade duration (AFD) of a wireless relay communication radio system with three sections, working in the multipath fading channel. The impact of fading parameters and multipath fading power on the LCR is analyzed based on the graphs presented

Microwave-hydrothermal synthesis of TiO2 and zirconium doped TiO2 adsorbents for removal of As(III) and As(V)

Microwave-hydrothermal method was used for the synthesis of TiO2 and TiO2 doped with zirconium. The method was fast and simple and adsorbents were used for removal of As(III) and As(V) from aqueous solutions. The adsorbents were characterized by BET surface area measurements and powder XRD. Experiments showed that TiO2 doped with 10% of Zr using the microwave-hydrothermal method have greater specific surface area and total pore volume in comparison with TiO2 synthesized using the same method. Better removal with doped adsorbent was obtained for both, As(III) and As(V). Further experiments were carried out with Zr doped TiO2 sorbent in order to examine kinetic of adsorption, influence of pH and effect of common anions present in natural waters. (C) 2014 King Saud University. Production and hosting by Elsevier B.V. All rights reserved

Different levels of humoral immunoreactivity to different wheat cultivars gliadin are present in patients with celiac disease and in patients with multiple myeloma

<p>Abstract</p> <p>Background</p> <p>Immunity to food antigens (gliadin, cow's milk proteins) is in the centre of the attention of modern medicine focused on the prevention of diseases, prevention which is based on the use of appropriate restriction diet. Detection of the enhanced levels of the immune reactions to antigen(s) present in food is from this point of view of great importance because there are reports that some of health disturbances, like celiac disease (CD) and some premalignant conditions, like monoclonal gammopathy of undetermined significance (MGUS), were vanished after the appropriate restriction diets.</p> <p>It is well known that gliadin is toxic to small bowel mucosa of relatively small population of genetically predisposed individuals, who under this toxic action develop celiac disease (CD). As the quantity of immunogenic gliadin could vary between different wheat species, the first aim of this work was to determine the percentage of immunogenic gliadin in ten bread wheat cultivars and in three commercially grown durum wheat cultivars. The second part of the study was initiated by results of previous publication, reporting that sera of some of multiple myeloma (MM) patients showed the presence of elevated levels of anti-gliadin IgA, without the enhanced levels of anti-gliadin IgG antibodies, determined with commercial ELISA test. It was designed to assess is it possible to reveal is there any hidden, especially anti-gliadin IgG immunoreactivity, in serum of mentioned group of patients. For this purpose we tested MM patients sera, as well as celiac disease (CD) patients sera for the immunoreaction with the native gliadin isolated from wheat species used for bread and pasta making in corresponding geographic region.</p> <p>Results</p> <p>Gliadin was isolated from wheat flour by two step 60% ehanolic extraction. Its content was determined by commercial R5 Mendez Elisa using PWG gliadin as the standard. Results obtained showed that immunogenic gliadin content varies between 50.4 and 65.4 mg/g in bread wheat cultivars and between 20 and 25.6 mg/g in durum wheat cultivars.</p> <p>Anti-gliadin IgA and IgG immunoreactivity of patients' sera in (IU/ml) was firstly determined by commercial diagnostic Binding Site ELISA test, and then additionally by non-commercial ELISA tests, using standardized ethanol wheat extracts -gliadin as the antigen.</p> <p>In both patients groups IgA immunoreactivity to gliadin from different cultivars was almost homogenous and in correlation with results from commercial test (except for one patient with IgA(λ) myeloma, they were more then five times higher). But, results for IgG immunoreactivity were more frequently inhomogeneous, and especially for few MM patients, they were more then five times higher and did not correlate with results obtained using Binding Site test.</p> <p>Conclusion</p> <p>Results obtained showed different content of immunogenic gliadin epitopes in various species of wheat.</p> <p>They also point for new effort to elucidate is there a need to develop new standard antigen, the representative mixture of gliadin isolated from local wheat species used for bread production in corresponding geographic region for ELISA diagnostic tests.</p

Fenton-like oxidation of an azo dye using mesoporous Fe/TiO2 catalysts prepared by a microwave-assisted hydrothermal process

Fe-doped TiO2 photocatalysts with different contents of Fe (0.5, 1.6, 3.4 and 6.4 %) were synthesized by a microwave-hydrothermal method and characterized by X-ray diffraction analysis, N-2 physisorption at 77 K and UV-Vis spectrometry. The characterization showed that the Fe ions were highly dispersed in the TiO2 lattice. It was found that all the synthesized catalysts had a mesoporous structure and that Fe-doping increased the BET surface area. The UV-Vis study showed that the absorption spectra were shifted to longer wavelengths (red shift) with increasing dopant concentration. The photocatalytic activity of the samples was evaluated by the decolorization of the textile dye Reactive Blue 52 (RB) in aqueous solutions under sun-like radiation in the presence of H2O2 (a heterogeneous photo-Fenton process). The photocatalyst with 3.4 % Fe was found to be the most efficient in the presence of H2O2. The effect of the initial pH of the dye solution was assessed and dissolution of iron ions was studied as a function of pH value. It was concluded that decolorization was more favorable in acidic pH, and that at pH values gt 4, the release of Fe ions into the solution was negligible. Photocatalytic degradation of 4-chlorophenol (4-CP) was investigated under the optimal conditions and it was shown that the catalyst was capable of degrading colorless pollutants