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The user's manual of software "Performance Curves" for the theoretical and quick determination of hydraulic machines (pumps and motors) operation parameters, is presented, avoiding the tedious and slow experimental evaluation and increasing efficiency in this activity with the smallest quantity of personnel. The software make more easy the determination of the functional parameters for hydraulic machines during the optimum regime of work, such as: the relationships among pomp and hydraulic motor efficiency with a non dimensional isogonaly coefficient, what is an approach of the kinematics likeness of rotational hydraulic machines geometrically alike, as well as a magnitude that characterizes the work regime of the given hydraulic machine. The pump and hydraulic motor total efficiencies curves have the maximum value for some specific values of the isogonaly coefficient, assuring a quite high precision, Also were obtained the maximum values for the hydraulic machine efficiency. [ABSTRACT FROM AUTHOR]

The researches that is carried out in the Chapingo Autonomous University of Mexico, in the Agricultural Mechanical Engineering Department (DIMA) and in the Havana Agrarian University, in the Agricultural Mechanization Center (CEMA), directed to the fluid power development., they allowed to develop an automated system, elaborated in Microsoft ® Excel 2000 on Windows, in a book Performance Curves calculation denominated, the one that facilitates the theoretical and quick determination of the performance parameters of the hydraulic machines (bombs and motors). For this book the work optimum regimen of the hydraulic machine was determined, the relationships among the efficiency of the bomb and hydraulic motor and the isogonaly coefficient. The results of the work show that the curves of the total efficiencies of the bomb and the hydraulic motor have the maximum value for certain values of the isogonaly coefficient, assuring a quite high precision. Lastly the maximum values of efficiency of the hydraulic machine were obtained. [ABSTRACT FROM AUTHOR]

As part of the researches that is carried out in the Chapingo Autonomous University of Mexico, in the Agricultural Mechanical Engineering Department (DIMA) and in the Havana Agrarian University, in the Agricultural Mechanization Center (CEMA), directed to the development of the fluid power. Three hydraulic gear pumps of 10, 32 and 50 cm³ displacements were evaluated with B multipurpose oil, in two different conditions, one totally new and the other one recovered by means of the filtrate after six months of use. The work was developed at CEMA Fluid Power laboratory. The methodology of the experience contemplated the use of an experimental installation with a test bank of hydraulic elements. A factorial design was used totally at random with 2 factors, one with three levels (10, 32 and 50 cm³ pump displacements) and another with new and recovered oils, repeating the process 4 times to different working hours, totaling 24 experimental units. In each experimental unit the flow, the power and the efficiency of the pumps were studied. The research results allowed to reach the following conclusions: there were not significant differences among the oils, the pumps fulfilled the technical characteristics presented by the maker satisfactorily. The volumetric efficiency in the three evaluated pumps was bigger than 90%. The half hydraulic power for pressure of 125 bar in the 10 cm³ displacement pump and nominal rotation frequency of 1 500 mn-1 was of 2,98 kW that is an appropriate value. For the 32 and 50 cm³ displacement pumps to 125 bar of pressure and nominal rotation frequency, the power stockings were respectively of 11,32 and 17,61 kW, being also these values appropriate. [ABSTRACT FROM AUTHOR]

In Cuba, the rice harvest is an operation that is carried out with the help of agricultural machinery, which represents strong investments. For this reason, the dynamics of the production process requires that the harvesting machines be in perfect technical condition during this period, because of that it is necessary to properly organize and plan the maintenance and repair system to ensure the increase of productivity efficiently. In the present work, the main results and experiences obtained in the research carried out during the mechanized harvesting of rice in Los Palacios Agribusiness Company of Grains in Pinar del Río Province, are stated. That was made to serve as a basis for decision making during the harvest of this precious grain; if one takes into consideration the large number of harvesters of different models that have been introduced in the country in recent years. [ABSTRACT FROM AUTHOR]

In Cuba, the rice harvest is an operation that is carried out with the help of agricultural machinery, which represents strong investments. For this reason, the dynamics of the production process requires that the harvesting machines be in perfect technical condition during this period, because of that it is necessary to properly organize and plan the maintenance and repair system to ensure the increase of productivity efficiently. In the present work, the main results and experiences obtained in the research carried out during the mechanized harvesting of rice in Los Palacios Agribusiness Company of Grains in Pinar del Río Province, are stated. That was made to serve as a basis for decision making during the harvest of this precious grain; if one takes into consideration the large number of harvesters of different models that have been introduced in the country in recent years. [ABSTRACT FROM AUTHOR]

The production of concentrated foods with high-energy efficiency indicators is currently a challenge in Cuba. Therefore, in this research, the objective is to carry out an energy evaluation of ¨Rómulo Padrón¨ Feed Factory based on the general consumption of the plant. For this, a diagnosis of the factory is carried out, the main tools that evaluate energy efficiency in this type of industry are determined and an improvement plan is presented. The results show average monthly values of production, energy consumed and the consumption index of 4589.4 t; 35,117 kWh and 7.56 kWh/t, and 108.13 t daily for the month of March; 802.93 kWh and 7.42 kWh/t, respectively. In addition, it was determined an unstable behavior of the energy consumed based on production (monthly and daily), with correlation coefficient values of 0.88 and 0.81, respectively. [ABSTRACT FROM AUTHOR]

This paper propose a theoretical model for determining the optimal moment to replace the kit of sprinkler irrigation and pressure regulators in a pivot. The model is based that the wear on the pressure regulators and nozzles make the decrease of the Irrigation Uniformity and this causes the yield loss. To compensate these losses an increase of irrigation depth is required to make up the deficit that occurs in areas of low delivery which generates in increased operating costs. Are considered in the model: costs for additional consumption of water and energy, maintenance and labor, and yield losses associated with areas with insufficient irrigation and over irrigation. The set of all these components is compared with the cost of the purchase and installation of a new sprinkler module, which allows the farmer to decide the right moment to make substitutions based on economic criteria. [ABSTRACT FROM AUTHOR]