INMATEH - Agricultural Engineering

6

Authors: Păun A., Nedelcu A., Neagoe V.

Productions of fodder crops harvested by the combine vary depending on the harvesting period, climate and soil conditions, plant growing level. Within the combine working process, the chopping drum is the most important working part, that is why three constructive variants, frequently used in fodder combines manufacturing, have been studied. The paper present the results of experiments performed for the trailed combine (CTF), endowed with equipment for harvesting grass fodder(EI) and ensiling corn (EP) and with three constructive variants of chopping drum.

6

Authors: Moiceanu G., Voicu Gh., Paraschiv G., Poenaru I.C., Pirnă I.

In nature the elements of a biological cluster, as they are just after harvesting or the material particles of a ground material never randomly distribute completely, but only after various distribution laws known in mathematical statistics. These distribution laws or functions can be Gauss laws, Lorentz laws, Euler laws etc. They can be graphically represented through two different curves: the probability density curve (the distribution curve) and the cumulative distribution law. The distribution functions are characterized by many specific parameters: average, standard deviation, limits, asymmetry etc. Studying different phenomena, in can be seen that although these belong to a different science, their distribution in frequency is alike, respectively the histograms have the same shape. For example, 90% of the physical phenomena can be explained with the normal distribution law (Gauss – Laplace law). In this paper a statistical study of physical–biological characteristics of two Mischanthus crops harvested in two consecutive years is presented: plants distribution according to height, the plants individual mass, plants diameter at the lower internod and at the upper internode, etc. There were determined the statistical parameters for various distribution laws (normal law, lognormal law, gamma law) which can point out the physical characteristics remembered before. Also, the specific mass of plants stalks was determined, based on its two components, bark and core, and also the energy consumption during stalk grinding process.

6

Authors: Patamanska G., Chehlarova-Simeonova S.

In recent decades changes in climate of Bulgaria have been observed, a warming trend was established, coupled with decreasing rainfalls, especially during the warm half of the year. This causes reduction of the agricultural production and prevents development of intensive agriculture without irrigation. There is a need for changing the existing irrigation systems towards improving their operation and management in order to develop productive, sustainable against altered climate conditions agriculture, which uses resources efficiently. The present article aims to analyze and evaluate the existing problems facing the irrigation sector in Bulgaria and to identify the main reasons for developmental delay. Key measures to be adopted for changing and renovation of existing irrigation systems and their management in order to increase the level of application of irrigation and water use efficiency are outlined.

8

Authors: Nagy E.M., Cota C., Cioica N.

In our country, at present, about 90% of the rural population uses the solid biomass as a source of heat. In Romania, biomass represents an important source of energy not only in rural but also in urban areas. Under these circumstances it is important to know the potential of biomass, both theoretical and real, not only at national level, but also divided by region or even in certain clearly defined areas. This paper brings in a general method for evaluate the energy potential of solid biomass at national level. The proposed method is based on systemic analysis on the one hand, and on the other hand, is based on utilization of statistics available at national level, and it can be applied to determine the energy potential of biomass coming from only a certain vegetal or wooden category, or from a certain area clearly defined. Also, in the present work is performed the evaluation of the real energy potential stored in agricultural residues resulting from harvesting of 10 ha of wheat. This method of evaluation is useful in determining the real energy potential of solid biomass and allows farmers to choose correctly the category of biomass grown to be energetically capitalized.

10

Authors: Cârdei P., Sfîru R., Stefănoiu M.D., Bădescu M., Boruz S., Lazar S.

This article is the first among a series of three articles describing mathematical models of fodder harvesting combines energegetics, in order to optimize their working regimes. Starting from scientific literature of 1970-1980s, the classical models have been improved and adjusted, obtaining new models and results. The calibrating method of mathematical models is shown in order to determine the model constants which are not given by specialty literature. There are made references to manner of validating the results and possible applications in a wider domain of technique and science. The three articles are structured according to complexity of mathematical models elaborated and used for optimization. The first article deals with generalities and unidimensional model, namely that model considering a unique speed for working regime, idle speed and at turnings. The second contains models that consider the working speed and turning speed equal to idle speed, and the third one will describe the models containing the three speeds as independent variables.