INMATEH - Agricultural Engineering

8

Authors: Sfîru R., Meca A., Cârdei P., Muraru V., Mihailov N., Atanasov At.

The article presents an optimizing method of agricultural equipment selection by users, dealing with databases and different objective functions, all finally materializing in benefits of energetic nature.

8

Authors: Stefănoiu M.D., Cârdei P., Vlădut V., Boruz S., Lazar S., Fodor M.

The problem of the optimization of working regimes of agricultural aggregates remains one of current, even if their approach began with over a half of century ago or even earlier. The reasons for the problem remains in the study are several: difficulty of verifying experimentally the optimality of solutions, the existence of some solutions with certain errors in the specialty literature of reference, the complexity of mathematical models on which is solve the problems of optimality and which introduce new parameters, necessary for obtaining of some functions goal which would have optimal points in the strict sense of local extremum, parameters which however are not usual and are difficult to determine by measurements. This article starts from a known method from the literature of the '70, corrects the solution and modifies slightly the mathematical model in order to make its calibration on a specific case so that the final results–the coordinates of the optimal point - to be obtained numerically and compared with data from the literature.

8

Authors: Ciupercă R., Popa L., Lazăr G., Drăgan R., Aliyev Ch.

The paper presents a comparative study on mechanized process of planting vegetable seedlings, performed by two types of machines among the most common and used vegetable farm machines, respectively machine with a section equipped with rotative distributor with buckets and a second type- with section endowed with supply chain and planting flexible disks. After the analysis performed, the advantages and disadvantages of two machine types studied have been found out, in terms of technology of vegetable seedling planting.

8

Authors: Cârdei P., Kostadinov G.

The article continues to present some results related to those in [3], thoroughly studying the results of aggregates working optimization operating mode designed to soil works, their significance and interpretation.

10

Authors: Danciu A., Brătucu G., Vlădut V., Brkic M.

Because of machining precision by pairing and running in (lapping) of the conjugated parts (piston and cylinder), the manufacturers, in order to not reject several parts assembled have recourse to execution of several diameters for these parts so that to be respected the conditions of ovality, conicity and the clearance between the conjugated components (max. 0.5÷2μm). To highlight the size and shape of the injection pump elements (piston and cylinder) worn-out after the completion of an operating cycle on the engine, were taken randomly from a sample of 141 injection pump elements, studying the distribution of these dimensions. The study of sizes distribution or of the effective deviations from shape of pistons and cylinders (bushings) of the worn off injection pumps elements, had as scope the knowledge of dimensions range of these, in order to check the possibilities to re-establish the operational state of these by lepping and re-pairing, pursuing and the determination of the number of measuring pneumatic completes, required in the resettlement process of the operational state of these. The statistical and mathematical processing aimed to: - determination of average diameters on two directions and in each of the three plans of measurement (both for pistons and for the cylinders of elements); - the determination of pistons ovality and cylinders respectively in the three plans of measurement; - the determination of averages for the piston conicity (cmed)) and for cylinders (CMED); - the determination of averages of the clearances in the three measurement plans for the conjugated parts; - sorting in ascending order of the pistons and cylinders; - highlighting the possibilities to restore the operating status of injection pump elements.

6

Authors: Meca V.A., Cârdei P.

The researches whose results are presented in this article aim to theoretically optimize the agricultural machines designed to prepare the germinating bed. For ploughing machinery, an optimization method has been known since 1970-1980. The movement resistance force of ploughing machines was expressed in relation with the forward speed by a formula known since the middle of past century. By means of this formula, the method of optimizing the working regime of ploughing machines was achieved. For the machines designed to preparing the germinating bed, the formula giving the calculation of movement resistance does not depend explicitely on speed, and the constant expressing the soil action in contact with working parts is a global one- a resistance density per machine working width. This constant should be experimentally determined. Our researches have aimed to modify this formula of calculation of movement resistance similarly with that of plowing machines and solve the optimizing problem taking into account the method already used. The researches frame within a scientific unifying current in the field of agricultural mechanics, which purpose is to reduce the diversity of expression by other procedures and generalization. Renouncing to use special formulae lead to large opportunities in conceiving, designing and testing agricultural machines, the agricultural mechanics formulae taking its roots in modern science base.

6

Authors: Ovidiu M., Muntean L. S., Drocas I., Muntean M.

The main purpose of this study was to identify seed conditioning procedures for the species Melissa officinalis L., considering the difficulties encountered due to the small size and weight. Starting from this objective and using a sieving machine one has tried to develop a sieve separation techniques of seeds from flowers. In the experimental tests, as working material seeds of two months old were used, taking into account two factors: time of sieving (5, 10 and 15 minutes) and sieving amplitude (0.2, 1 and 2.2 mm). The results from experimental investigations have shown the possibilities to use sieve conditioning of Melissa officinalis L. species seed, but also noted the need to use further procedures for seed separation from impurities using currents of air. The main result consists of identifying the sieve time and the amplitude of the sieve.

8

Authors: Constantin N., Irimia D., Persu C., Cociu A.

Multifunctional aggregate for soil tillage in agricultural fields - MATINA is based on conservative agriculture system which consists in the main soil operation without furrow overturning, the vegetal wastes being superficially incorporated and at least 30% out of their amount being maintained at soil surface. This system assures competitive productions in terms of quality and quantity similar to those classically obtained, but with reduced costs and high profit, while improving soil features and preserving environment. The aggregate laboratory-field tests have been performed within private agricultural farms in Dolj and Teleorman county for tilling the soil in unplugged lands (in spring) and in wheat and barley stubble (in summer), during April-August 2011. MATINA performs at a single passing, the following agricultural operations: soil deep loosening with loosening parts, in order to facilitate plants roots easily to penetrate into the soil in search of water and nutritive elements; preparing the germinating bed with specific working parts; soil breaking and additional leveling by means of rollers with rods. During the field-laboratory tests, procedures elaborated by INMA-DI have been used, measuring and monitoring equipment (EMM) in terms of metrology verified, have been also used and appropriate working qualitative and energetic indexes have been obtained. Productions of crops set up in spring of 2011 in soil worked with MATINA have been similar to those obtained by classical system, with expenses by about 50% less.

8

Authors: Ivan Gh., Nedelcu M.

The article presents the part four of the study of pile displacement on the straw walker of conventional grain combine harvesters, in order to determine the structural and functional characteristics of the straw walker, to increase its working capacity. The material presented in the article represents the study of functions tsalt(k,α,δ,f) and S(k,α,δ,f,), duration and size of displacement of a pile jump on the shaking element at a complete rotation of it

8

Authors: Popa Gh., Constantinescu A., Dumitru I. , Vlădut V.

The paper presents the calculation of traction of a tractor equipped with additional hydrostatic transmission of mechanical transmission. The variation of the hydraulic parameters – the working liquid pressure, the hydraulic pump delivery – modify the parameters of the hydraulic motor – the rotation speed of the motor axle, the motor torque – and, also, the traction performances of the tractor. Also, wheeled traction performance are influenced by constructive and functional parameters of tractor tire, parameters influencing the interaction between the ground and wheels.