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J. P. A. , Sadowski N. Electromagnetic modeling by finite element methods , Marcel Dekker Inc , New York , 2003 . [4

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The practical implementation of precision crop production nowadays is becoming more and more widespread. Numerous experiments and farmers’ practical experiences verify the positive impacts of precision nutrient supply on farming. Precision weed control started to spread later, partly due to technical difficulties, partly to the lack of necessary software support that was developed later. The introduction of a new technology requires complex farm-management decisions, including the consideration of economic correlations (costs-yield-income) as well as high-level skills and significant investments from the farmer. These investments can be returned from the income surplus realized through increasing yields and decreasing farming costs. Extra income can also come from the decreasing material costs which, however, do not necessarily compensate the extra costs of implementing the new technology and depends very much on the utilization of savings from different herbicide doses used for the treatment of plots, considering the soil qualities. This study, utilising the data of a technological experiment carried out in Hungary, presents the results of a stochastic simulation model developed with the adaptation of finite element method. The examination was executed at sub-plot level, dividing the plots into small parcels. Our aim was to examine the impact of precision nutrient application and differentiated spraying of herbicides on production costs and yield, as well as the impact of changes on gross margin (income) and the returns on technological development.

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E cikkel szeretnénk fölrázni a tervezéssel foglalkozó mérnöki társadalmat. Napjainkban a gyakorló tervezői tevékenységet végző mérnökök körében még mindig egyfajta „misztikum” kategóriába esik a végeselemmódszer, ezért szinte kétely nélkül fogadják el azokat a számítási eredményeket, amit végeselemes szoftver produkál. A cikkben arra kívánjuk a hangsúlyt helyezni, hogy miképp befolyásolják a számítási eredményeket a választott elemtípusok, valamint a végeselem-háló különböző geometriai kialakításai. Ezt egy konkrét példa alapos és átfogó elemzésén keresztül tesszük meg. Tapasztalatunk szerint ugyanis éppen e kérdés elhanyagolásából, az erre irányuló figyelem hiányából adódik a mérnökileg már nem elfogadható mértékű hibákat tartalmazó számítások legtöbbje.

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A mai mérnöki gyakorlatban a falazatok alakváltozási jellemzőit kísérleteken alapuló, fenomenológiai összefüggések segítségével határozzák meg. A cikkben arra a kérdésre keressük a választ, hogy meg lehet-e határozni a falazatot alkotó összetevők – a falazóelem, illetve a habarcs – alakváltozási jellemzőinek, geometriájának és a kötési módnak az ismeretében a falazat rugalmassági és nyírási modulusát. A cikk röviden ismerteti az alakváltozási jellemzők meghatározásának elméleti módjait, és új homogenizációs modelleket mutat be kitöltetlen állóhézagú falazat alakváltozási jellemzőinek meghatározására. A bemutatott és az általunk alkotott modellek használhatóságát végeselem-módszerrel igazoltuk.

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Abstract  

This work presents the modelling of heat transfer in a polymer sample submitted to a microwave field in the quartz column of a dilatometer surrounded by vacuum to avoid convection. The temperature rise is studied in transient state by the finite element method. It is assumed that a uniform and constant heat production is maintained in the entire volume of the sample. It is shown that it is possible to design the set composed of the sample and of the column to achieve a nearly uniform temperature in the whole volume of the sample while its temperature is raised from 20 to 250°C at a heating rate of 5 deg·min−1.

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Cereal Research Communications
Authors: E. Firatligil-Durmuş, A. Sýkorová, E. Šárka, Z. Bubník, M. Schejbal and J. Příhoda

Digital image analysis was used to test the quality parameters of six varieties of Triticum aestivum L. and one variety of Triticum duro-compactum L. — projected area, equivalent diameter, MaxFeret and MinFeret (minimum or maximum perpendicular distance between parallel tangents touching opposite sides of the profile of the chosen object), perimeter, thickness and crease depth (both measured using a digital calliper) of a kernel ranging from 16.52–20.22 mm 2 , 4.58–5.07 mm, 16.70–20.82 mm, 6.21–7.29 mm, 3.32–3.78 mm, 2.69–3.12 mm, 0.23–0.42 mm. The size data were used for calculation of volumes and surface areas of wheat kernels modelled as a general ellipsoid. The calculation of surface area using finite element method (FEM) was based on computer software MAPLE 9.0 and the results were compared with a simplified method. The volumes of kernels from the ellipsoid model were corrected with consideration of measured average crease depth; the difference was then max. 3.6%.We tested the correlation of volume and surface areas obtained from the ellipsoidal model with the measured projected areas; the resulting high correlation coefficient for the varieties of Triticum aestivum enables the use of only 2D image analysis measurement, for quick estimation of surface and volume parameters, without time consuming thickness measuring. However, the shape of Triticum duro-compactum kernels was a little different and the designed geometrical model was thus not suitable.We recommend image analysis as a simple and rapid method for obtaining the parameters of wheat grain for engineering purposes.

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It is well known that one of the most popular methods of connecting members in structural steel work is the bolted end-plate connection. Bolted end-plates are simple in their use and construction. But they are extremely complex in term of analysis and behavior since the connection behavior significantly affects the structural frame response and therefore it has to be included to the global analysis and the design of frame. The present paper deals with the structural behavior of full-scale stiffened and un-stiffened cantilever connections of typical I sections. The connection between the extended end-plate to the column flange is achieved by means of high strength bolts in each case. In order to obtain experimentally the actual tension force induced within each bolt, strain gauges were installed inside each one of the top bolts. Thus, the connection behavior is characterized by the tension force in the bolt, the extended end-plate behavior, the moment-rotation relation and the beam and column strains. Thereby, it is important to predict the global behavior of column-beam connections by means of their geometrical and mechanical properties. The experimental test results are compared to those obtained by means of a numerical approach based on the finite element method and is coupled to the theory of non-smooth mechanics. All the arising non-linearities in the connection are described through a non-monotone multi-valued reaction-displacement law. Thus, the problem is formulated as a hemivariational inequality leading to a sub-stationarity problem of the potential or the complementary energy of the connection. This simulation problem is solved by applying a non-convex non-smooth optimization algorithm. The comparison of the results of the experimental testing program with the numerical simulation proves the effectiveness of the proposed numerical method.

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-963-7064-25-8 ) [10] Mankovits T. , Vámosi A. , Kocsis I. , Huri D. , Kállai I. , Szabó T. ( 2015 ), Shape design of axially symmetric rubber part using finite element method and

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] Athani S. S. , Shivamanth , Solanki C. H. , Dodagoudar G. R. ( 2015 ), Seepage and stability analyses of earth dam using finite element method . Aquatic Procedia , 4 , 876 – 883 . [9

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. [6] PLAXIS software -based on the finite element method, 2016. [7] Adorjányi K. , Füleki P. Performance parameters and

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