Enhancement of Pulley and Belt Mechanism using Finite Element Analysis

The pulley and belt mechanism has been developed to supply the needs of power transmission. This mechanism and especially the V-belt drive mechanism is widely used in the agricultural industry, however, it is facing numerous challenges due to the heat generated in the belt during its operation. The rate of hysteresis loss induced by the frequent use of the belt is important which made it a major concern for engineers. The heat produced on the contact surface during the process under the effect of friction is transformed into heat, which leads to the degradation of the microscopic polymer molecular chains and the fast aging of the rubber part, therefore it adversely impacts the durability of the V-belt. To tackle this encountering problem, we have conducted a thermal study using finite element simulations on a pulley and belt mechanism. We sight to improve the design by adding the so-called cooling fins to the pulley, mainly to increase the heat transfer area and reduce the temperature of the pulley, hence improve its efficiency along the service life. And by examining these new models using finite element methods (FEM), the results show a decreasing in the temperature, therefore increasing in the lifetime of the belt is expected and reduce the problems which occur in high temperature

Evaluation the Effect of Particle Sphericity on Direct Shear Mechanical Behavior of Granular Materials Using Discrete Element Method (DEM)

Granular materials are an essential component of many fields, such as the medicine and agriculture industries, where their behavior is affected by the properties of constituent particles. The Discrete Element Method (DEM) is a potential technique used to describe the mechanical behavior of granular materials by making a mechanical model which describes the affected parameters, and one of these parameters is the shape of particles. It is an important characteristic that is represented by a sphericity index. In this study, the macro and micro-mechanical shear behaviors of granular materials are investigated using the Discrete Element Method (DEM). For this purpose, a three-dimensional (3D) program (EDEM) was developed on the basis of (DEM) and was used to model various particle shapes for a direct shear test. An assembly with a different particle center distance was prepared. The results showed a changing relationship between shear strength and the sphericity index, and micro-mechanical responses showed that particle shape affected the shape and the thickness of the shear zone

Talajtényezők hatásának kvantifikálása a csírázásra és kelésre = Quantification of soil factors affecting germination and emergence

A csírázás és kelés, a növény egyedi életének kezdete, döntően meghatározza a produkcióra képes növények számát és az asszimiláció idejét. A kutatás célja a legfontosabb talajtulajdonságok (hőmérséklet, víztartalom, a nehézfémszennyezés, a pH-érték, a talajművelési mód stb.) kelésre gyakorolt hatásának vizsgálata, kvantifikálása és a szimulációs modellekhez illeszkedő algoritmusok kifejlesztése volt. Laboratóriumi és szabadföldi kísérletekkel a kukorica és a repce kelését jellemeztük különböző talajokban, meghatároztuk a talajjellemzők kritikus értékeit, s a keléssel való összefüggésüket. A produkciós modellekben a tőszám a becslés alapja. A jól ismert produkciós modellek, csak a kelés idejét becslik, a kikelt növények száma input paraméter. Kutatásunk végső célja e fontos bemenő adat becsülhetősége volt. A modellben a talajfeltételek jellemzésére elkülönítettünk a hő-, víz- és ún talajtényezőt. A hő- és víztényező egyszerű faktorok, míg a talajtényező összetett, értéke függ a művelési módtól, és annak idejétől, a vetésmélységtől, a só és nehézfém koncentrációtól, valamint a pH-értéktől. A becsült eredmények a talajtényező fontosságát igazolják, elsősorban szélsőséges feltételelek esetén. Eredményeink közvetlenül hasznosíthatók a tőszám becslésére, tehát a produkciós modellekben a jelenlegi input kiváltására. Az eredmények felhasználhatók a pontmodellek területi kiterjesztésének megalapozásánál, a környezeti monitoringnál vagy a precíziós gazdálkodásnál. | Emergence represents the point in time when seedling photosynthetic autotrophism begins and determines the maximum number of plants and the duration of the time of plant assimilation. Our object is determination of main soil factors, quantification of influence of these factors, development of algorithm for simulation models. Germination and emergence of two crops, maize and rape were charachterised in the different soil types with laboratory experiments and with measuring on the fields. It was determined critical value of soil temperature, moisture content, heavy metal concentration, pH value, soil crust and cultivation method. The well-known production models determine the length of emergence, but they require plant density as an input parameter. Plant density is a critical input data that is used for the calculation of crop yield in the models. The aim of present work was to substitute plant number as a model input parameter with an estimation to gain a real number of emerged plants. To characterize soil conditions three factors were used in the model: "temperature", "water" and "soil" factors. Estimated results demonstrate high priority of "soil factor", when soil conditions are extreme. Determination of number of emerged plant and the time of emergence make possible to develop area models based on point models. This model is a means for precisions agriculture and for environmental monitoring