318 research outputs found

    Relation between numerical model and vibration: behavior diagnosis for bucket wheel drive assembly at the bucket wheel excavator

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    A drive assembly of bucket wheel at the bucket-wheel excavator (BWE), as a rule, is a unit characterized by large force having huge torque and mass with structures in different arrangement including the support structures as well. Behavior prediction is of crucial importance in order to apply the right approach of operation and maintenance on gearbox, electrical engine as well for structural elements supporting this assembly. It is obvious that vibrations measured at distinctive points of the entire drive assembly and support structure represent the main prediction parameter. The measurement results are used to confirm mathematical model developed by means of finite element method, which is based on theory on flexibility, static and dynamical review for obtained result

    Variability and Correlations of Some Investigated Traits of Perennial Ryegrass Populations

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    Perennial ryegrass (Lolium perenne) is one of the most important perennial forage grasses for temperate climates. It is a highly productive grass with the highest nutritive value (Sokolovi et al., 2002). In Serbia, breeders have developed perennial ryegrass cultivars with high stabile yield and quality with different times of maturity and resistance to drought and frost. The initial breeding material were usually wild populations (Charmet et. al., 1996) with high variability and adaptability. These characteristics lend themselves for selection of superior genotypes. But breeding for some important agronomic traits may influence others. This relationship between traits and breeding population variability is the objective of this article

    Distribution of Trace Elements in Plant Parts of Red Clover (\u3cem\u3eTrifolium pratense\u3c/em\u3e L.)

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    There is little information on the distribution of minerals in plant parts although factors affecting mineral content in forages have been well investigated (Fleming, 1973; Whitehead et al., 1985). The aim of this investigation was to determine the trace mineral content in plant parts of different cultivars of red clover (foreign and domestic) and to assess differences between cultivars. The existence of significant differences between cultivars would indicate the possibility of selecting cultivars to satisfy particular animal requirements for minerals

    Paleolinguistics brings more light on the earliest history of the traditional Eurasian pulse crops

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    Traditional pulse crops such as pea, lentil, field bean, bitter vetch, chickpea and common vetch originate from Middle East, Mediterranean and Central Asia^1^. They were a part of human diets in hunter-gatherers communities^2^ and are one of the most ancient cultivated crops^3,4^. Europe has always been rich in languages^5^, with individual families still preserving common vocabularies related to agriculture^6,7^. The evidence on the early pulse history witnessed by the attested roots in diverse Eurasian proto-languages remains insufficiently clarified and its potential for supporting archaeobotanical findings is still non-assessed. Here we show that the paleolinguistic research may contribute to archaeobotany in understanding the role traditional Eurasian pulse crops had in the everyday life of ancient Europeans. It was found that the Proto-Indo-European language^8,9^ had the largest number of roots directly related to pulses, such as *arnk(')- (a leguminous plant), *bhabh- (field bean), *erəgw[h]- (a kernel of leguminous plant; pea), *ghArs- (a leguminous plant), *kek-, *k'ik'- (pea) and *lent- (lentil)^10,11,12^, numerous words subsequently related to pulses^13,14^ and borrowings from one branch to another^15^, confirming their essential place in the nutrition of Proto-Indo-Europeans^16,17,18^. It was also determined that pea was the most important among Proto-Uralic people^19,20,21^, while pea and lentil were the most significant in the agriculture of Proto-Altaic people^22,23,24^. Pea and bean were most common among Caucasians^25,26^, Basques^27,28^ and their hypothetical common forefathers^29^ and bean and lentil among the Afro-Asiatic ancestors of modern Maltese^30^. Our results demonstrate that pulses were common among the ancestors of present European nations and that paleolinguistics and its lexicological and etymological analysis may be useful in better understanding the earliest days of traditional Eurasian crops. We believe our results could be a basis for advanced multidisciplinary approach to the pulse crop domestication, involving plant scientists, archaeobotanists and linguists, and for reconstructing even earlier periods of pulse history

    Reconstructive Procedures after Total Gastrectomy for Gastric Cancer

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    Till this day, there are more than 60 described surgical procedures of the intestinal reconstructions after a total gastrectomy. In 1897, Schlatter reconstructed the digestive tract by creating a termino-lateral esophagojejunostomies that was the first successful total gastrectomy. Many of the total gastrectomy pioneers did the reconstruction by esophagoduodenostomy or by forming a loop esophagojejunostomy. The main reconstruction modalities after a total gastrectomy are a restitution of the intestinal continuity, without a preservation of the duodenal food passage (esophagojejunostomy with a Roux-en-Y configuration) and a restitution of the intestinal continuity with a preservation of the duodenal passage (esophagojejunostomy with Roux-en-Y configuration and forming of the lateral-terminal jejunoduodenal anastomosis double tract and jejunal interposition by Longmire). The surgeries in these categories can be combined with forming of an enteral pouch or a stomach reservoir which would simulate a reservoir of a normal intact stomach. The ideal reconstruction procedure after total gastrectomy should replace all lost functions of the stomach. Preservation of duodenal transit with replacement of the jejunal segment, the so-called physiological route, is now believed to be preferential for postoperative nutritional condition, prevents persistent postgastrectomy syndrome, and improves the quality of life. Reconstructive procedures which allow duodenal passage should be regarded as a key to physiological reconstruction

    Ultrasound and shacking-assisted water-leaching of anions and cations from fly ash

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    Two mechanical extraction techniques were used for the extraction of environmentaly interesting components of coal fly ash: shaking, during which the extraction process lasted from 6 up to 24 h, and sonication that lasted from 15 up to 60 min, using water as extractant. The concentration of anions in fly ash extracts was determined by ion chromatography, while atomic absorption spectrometry was used for determination of: As, Pb, Cd, Ni, Cr, Zn, Cu, Fe, Mn and Al. The ultrasonication yielded slightly higher amounts of extracted anions as well as Pb, Al, Mn and Fe cations, while shaking-assisted extraction was more efficient for the Cr, As, Zn and Ni ions. The changes in pH value, particle size distribution within colloid solution, zeta potential and conductivity during ultrasound-assisted extraction were measured in order to explain changes that occur on the surface of fly ash particles contacting water and different processes (adsorption, ion exchange and flocculation) that develop under natural conditions. Principal Component Analysis was used for assessing the effect of observed process parameters. It is essential to evaluate quantity of these elements leachable from coal fly ash into the surface waters in natural conditions in order to prevent contamination of the environment

    Hyperendemic Dirofilaria immitis infection in a sheltered dog population: an expanding threat in the Mediterranean region

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    A study on the occurrence of Dirofilaria immitis and its vectors was carried out in order to assess the prevalence of the disease in dogs in previously non-endemic areas of southern Italy. Blood samples (n = 385) and mosquitoes (n = 1540) were collected in two dog shelters and analysed by Knott's test and duplex real-time PCR, respectively. Dirofilaria immitis was the most prevalent filarioid (44.2%), while Culex pipiens was the most prevalent mosquito species (68.8%). This high prevalence of D. immitis infection confirms this location as one of the most hyperendemic foci of dirofilariosis in Europe

    Technifermion Representations and Precision Electroweak Constraints

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    We discuss the selection of fermion representations in technicolor models with a view toward minimizing technicolor contributions to the precision electroweak SS parameter. We present and analyze models that involve one technifermion SU(2)L_L doublet with standard-model singlet technifermion sectors that lead to walking behavior, which further reduces SS. We also consider models that have technifermions in higher-dimensional representations and study embeddings in extended technicolor theories.Comment: 8 pages, late

    The comparison of sample extraction procedures for the determination of cations in soil by IC and ICP-AES

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    This paper presents the extraction of cations from a soil sample, type ranker on serpentinite, in deionized water, by use of three different extraction techniques. The first extraction technique included the use of a rotary mixer, the second technique involved the use of a microwave digestion system with different extraction temperatures, and the third technique employed an ultrasonic bath with different extraction times. Ion chromatography was used for determining the concentration of Li, Na, K, Ca, Mg and ammonium ions in soil extracts with subsequent determination of concentrations for all cations, except for ammonium ion extraction, conducted by Inductively Coupled Plasma-Atomic Emission Spectrometry. The results of cation extractions showed that microwave assisted extraction was most efficient for the Li, Na, K, Ca, Mg, Co, Mn, Ni, Pb and ammonium ions. Use of a rotary mixer for extraction was most efficient for Cd and Zn ions, while use of ultrasound bath was most efficient for Cr, Cu, Fe and Al ions. Several times higher amount of cations extracted by the most efficient, compared to the second best technique, under optimal conditions, were noticed in the case of: Ca, Mg, Co, Mn, Fe, Al, and Zn ions

    Invasive mosquito species in Europe and Serbia, 1979 – 2011

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    People’s increased mobility and international trade play important roles in the dissemination of vectors and the pathogens that they could transmit. Climate change is likely to become another important consideration in the near future. The responses of insects to these changes (in addition to potential for increased vector capacity) could allow for a broadening of their colonized areas and the invasion of new sites. In the last couple of years a number of pathogen introductions into Europe have been recorded. The latest (Ravenna, Italy, 2007) was caused by the tropical Chikungunya virus, which is transmitted by the “Asian tiger mosquito”, a species introduced into Europe in 1979 (Albania), and then Italy in 1990. Invasion continued to France in 1999 and until present, Belgium, Montenegro, Greece, Switzerland, Croatia, Spain, Bosnia and Herzegovina, the Netherlands, Slovenia, Germany, Serbia, Bulgaria and Turkey have been invaded. Deciphering the true cause of changes in the distribution of mosquitoes is difficult and complex and depends, to a great extent, on the availability of data obtained by monitoring. In order to assist in vector-borne disease preparedness, distribution of the most important invasive species St. albopicta in Europe and particulars of findings in Serbia are conferred
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