248 research outputs found

    Tensile Membrane Structure Forces Dependence on Different Parameters Under Point Load Action

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    Point load actions may have a significant impact on deflections of tensile membrane structures. Research presented in this paper is aimed at exploring the effects of point load actions on membrane forces of tensile membrane structures. Therefore, three different parameters of the structure were varied, and the membrane forces resulting from point loads were monitored. Variable parameters are the height of the model, the intensity of prestressing forces, and the orientation of the membrane material. The research was done on models in specialized software. In order to evaluate the significance of point load effects, membrane forces were compared to those under snow load. The results of the research show the layout of membrane forces under point load and dependence of maximal membrane forces on the varied parameters. Specific sets of analyzed parameters lead to significant values of maximal membrane forces under point load actionKoncentrisane sile mogu da izazivaju znatne ugibe zategnutih membranskih konstrukcija. Istraživanje predstavljeno u ovom radu bavi se efektima dejstva koncentrisane sile na sile zatezanja membranskih konstrukcija. Kako bi se ovi efekti ispitali, varirana su tri parametra konstrukcije, a praćene su sile zatezanja izazvane dejstvom koncetrisane sile. Varirani parametri jesu visina modela, intenzitet sila prednaprezanja i orijentacija membranskog materijala. Istraživanje je sprovedeno na modelima formiranim u specijalizovanom softveru. Kako bi se ocenio značaj efekata dejstva koncentrisane sile, rezultujuće sile zatezanja upoređene su sa silama zatezanja pod dejstvom opterećenja od snega. Rezultati istraživanja pokazuju raspored intenziteta sila zatezanja u membrani pod dejstvom koncentrisane sile i zavisnost maksimalnih sila zatezanja od ispitivanih parametara. Pri određenim kombinacijama ispitivanih parametara, koncentrisana sila izaziva vrlo značajne sile zatezanja

    Reliability Ensuring Models of Complex Facilities in Thermal Power Plants

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    Ova studija ima za cilj da prikaže mogućnost generisanja modela obezbeđenja pouzdanosti složenih postrojenja u termoelektranama.The goal of this study is to show the possibility of generating reliability ensuring models of complex facilities in thermal power plants

    A note on extremal Sombor indices of trees with a given degree sequence

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    We note here that the problem of determining extremal values of Sombor index for trees with a given degree sequence fits within the framework of results by Hua Wang from [Cent. Eur. J. Math. 12 (2014) 1656-1663], implying that the greedy tree has the minimum Sombor index, while an alternating greedy tree has the maximum Sombor index

    Assigning Projects to Project Managers in a Multiple-Project Management Environment: A Pilot Study of a Decision Support Model

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    Project assignment is considered one of the most critical project decisions since it influences the performance of projects, and eventually the performance of the organization. Despite its importance, the literature reveals two major gaps on project assignment criteria and methodology. To close these gaps, this study proposes an additional set of project assignment criteria and a systematic methodology for project assignments (DSM). By using the concepts of these case study research combined with a literature review, the important potential criteria for project assignments are identified. These criteria are used in conjunction with the concepts of the analytic hierarchy process (AHP) and the integer programming (IP) to develop a DSM for one company. The DSM is executed and validated with the company\u27s information. As a past of this research project, this paper illustrates the results of the pilot study to be developed for the feasibility study of the DSM development

    Mi u dolar (ne) verujemo - posledice smanjenja globalne uloge dolara po ukupnu moć Sjedinjenih američkih država

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    This paper examines links between threatened status of the U.S. dollar as a global currency in the international monetary system and its consequences for U.S. power in international relations. In the first part of the paper, authors try to establish a connection between the status of global currency and power; the second part is devoted to the analysis of the historical status of the dollar, while in the third section, authors analyze the potential rivals. Fourth section of this paper presents the economic and political consequences of the reduced global role of dollar on U.S. power.Autori u ovom radu pokušavaju da odgovore na pitanje da li je ugrožen status američkog dolara kao globalne valute u međunarodnom monetarnom sistemu i da istraže posledice koje opadanje uloge dolara može imati po ukupnu moć SAD u međunarodnim odnosima. U prvom delu rada uspostavlja se veza između statusa globalne valute i moći, drugi deo je posvećen istorijskoj analizi statusa dolara, dok se u trećem delu analiziraju potencijalni rivali. U četvrtom delu se izlažu ekonomske i političke posledice smanjenja globalne uloge dolara na moć SAD

    Značaj izbora sorte u intenzivnoj proizvodnji lucerke

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    Alfalfa is an autotetraploid, perennial forage crop adapted to different environments and management systems. Trial with 12 alfalfa populations was established in spring of 2014. The research involved 9 commercial alfalfa varieties from IFVCNS, Serbia, and included 3 experimental populations in the final phase of breeding program. The main objectives of this paper were to examine the impact of variety selection on alfalfa yield and plant height in intensive cutting management in order to define harvesting strategies (using 6 and 5 cuts per season), with main goal to maximize profit on alfalfa farms in Serbia and Southeast Europe. Our study clearly demonstrates that there is genetic potential in some Serbian varieties (NS Sila, Nera, NS Jelena, and Banat VS) for use in intensive cutting systems with 6 cuts per year that can meet farmers' needs in conventional or organic type of alfalfa hay production.This research represents an initial guideline for the alfalfa variety selection in intensive cutting management systems in Serbia and Southeast Europe.Lucerka (Medicago sativa L.) je najznačajnija višegodišnja krmna biljka visokih prinosa krme, sena, senaže, odlične hranljive vrednosti. Sistem kosidbe predstavlja odlučujući faktor u determinaciji prinosa i kvaliteta lucerke. U cilju provere reakcije populacija lucerke stvorenih u Institutu za ratarstvo i povrtarstvo na intenzivan sistem kosidbe (sa primenjenih 6 otkosa u II i III godini života i 5 otkosa u IV godini trajanja useva) postavljen je ogled u Novom Sadu u 2014. godini, a rezultati su praćeni tokom 2015-2017. godine. U ispitivanje je uključeno 9 priznatih sorti i 3 eksperimentalne populacije lucerke stvorene u različitom vremenskom periodu, primenom različitih metoda oplemenjivanja i germplazme različitog porekla. Dobijeni rezultati pokazuju da režim kosidbe lucerke treba prilagoditi tipu/grupi sorti, načinu proizvodnje i rejonu gajenja. Najveći prinosi suve materije tokom perioda ispitivanja registrovani su kod sorti NS Sila (18,4 t/ha), Nera (18,2 t/ha), Banat VS (17,9 t/ha) i NS Jelena (17,7 t/ha) u intenzivnom sistemu kosidbe. Režim kosidbe sa 6 otkosa u Srbiji predstavlja realan način proizvodnje, ali prilagođavanje ovom sistemu kosidbe zavisi od cilja proizvodnje, sorte, rejona gajenja, starosti useva. Genetički potencijal NS sorti lucerke koji odgovara maksimalnom intenzitetu kosidbe sa 6 otkosa u godini ostvaren je sa sortama NS Sila, Nera, Banat VS i NS Jelena, a za sistem kosidbe sa 5 otkosa u godinama pune eksploatacije, a koji najviše odgovara farmerima u umereno-kontinentalnom klimatu Srbije, mogu se preporučiti i sorte NS Banat ZMS II, NS Mediana ZSM V. Ostvareni rezultati predstavljaju značajan doprinos razumevanju značaja primene intezivnog sistema kosidbe tokom godina iskorišćavanja a posebno kritičnoj fazi vezanoj za izbor sorte i različite rejone gajenja, načine iskorišćavanja, kao i potrebe različitih tržišta za senom lucerke

    Soil pollution in the Hungarian-Romanian border region (Valley of Körös-Cris rivers)

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    The investigation assessed and evaluated the soil polluting activities in 30 Romanian and Hungarian settlements in the region of the Double, Black and White Körös-Cris Rivers. Pb concentrations are mainly higher than the limit values with maximum values registered in the area of landfill and near the roads. The concentration of Cu and Zn in soils of the region is below the alarming values. In some places Cd levels in soils reached the alert threshold. Plant samples mostly do not contain higher than permitted levels of heavy metals. One of the main goals of the study is to contribute to the future sustainable use of the environment and conservation actions in the region in order to implement regional development policy. We must therefore address the social activities that involve a risk of soil pollution in the region, especially in the Körös-Cris Valley. Science-based assessment of the level of pollution can lead to the development of implementing procedures to reduce the impact of these activities. The most important result of the quality and quantity analysis of polluting activities in the region is territorial definition of soil heavy metal load

    Učestalost produženog boravka u ICU zbog razvoja reperfuzijskog sindroma nakon karotidne endarterektomije – petogodišnji presjek iz UKC Banjaluka

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    Carotid endarterectomy (CEA) ist the most most frequently performed vascular surgical procedure, and belongs to the type of preventive interventions. Reperfusion syndrome is relatively rare complications of this procedure, but with clinically significant and potentially fatal consequences that can seriously compromise the outcome of treatment after CEA. The focus of this study is on frecuency of development of RS, the factors that favor its occurrence, causes of hemodinamc instability, the modalities of early diagnosis, as well as the possibilities of preventing this complication. The research covered the period from 2018 to 2022 during wich 963 CEA were performed.Karotidna endarterektomija (CAE) je najčešće izvođeni operativni zahvat vaskularne kirurgije. Spada u niz preventivnih postupaka. Reperfuzijski sindrom je relativno rijetka komplikacija ovog operativnog zahvata, ali s klinički značajnim i potencijalno opasnim posljedicama koje mogu ozbiljno ugroziti ishod liječenja nakon CEA. Fokus ovog rada je na učestalosti razvoja cerebralnog reperfuzijskog sindroma (CRS), čimbenicima koji pogoduju njegovoj pojavi, uzrocima hemodinamske nestabilnosti perioperativno, te modalitetima rane dijagnoze i terapijskog pristupa, kao i mogućnostima prevencije razvoja ove komplikaciju. Istraživanje je obuhvatilo petogodišnje razdoblje (2018–2022) KB Banjaluka u kojem su urađene 963 karotidne endarterektomije

    Soil pollution in the Hungarian-Romanian border region (Valley of Körös-Cris rivers)

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    The investigation assessed and evaluated the soil polluting activities in 30 Romanian and Hungarian settlements in the region of the Double, Black and White Körös-Cris Rivers. Pb concentrations are mainly higher than the limit values with maximum values registered in the area of landfill and near the roads. The concentration of Cu and Zn in soils of the region is below the alarming values. In some places Cd levels in soils reached the alert threshold. Plant samples mostly do not contain higher than permitted levels of heavy metals. One of the main goals of the study is to contribute to the future sustainable use of the environment and conservation actions in the region in order to implement regional development policy. We must therefore address the social activities that involve a risk of soil pollution in the region, especially in the Körös-Cris Valley. Science-based assessment of the level of pollution can lead to the development of implementing procedures to reduce the impact of these activities. The most important result of the quality and quantity analysis of polluting activities in the region is territorial definition of soil heavy metal load
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