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This paper presents the used methodology to calculate the present and future potentials of total biomass wastes, from the economic, social, environmental and technological point of view in accordance with the principles of sustainable development. From the values of sugarcane, coffee, rice, and sawmill wastes, through information provided by the main producing companies in Cienfuegos province, it was possible to determine the total energy delivered, as well as the amount of CO2 emitted into the atmosphere. In the case of the bagasse, the total energy was 4.409E+08 MJ, leaving 137 652.9 t CO2 to emit in the atmosphere. For the filter cake it was 7.093E+08 MJ and 221 423.9 tCO2. In the case of coffee and rice residues these values were 4.808E+05 MJ with 184 tCO2 for coffee and 6.34E+07MJ with 19 868.87 tCO2 for rice, respectively. Finally, the total energy for sawmill waste was 4.108E+07 MJ and 2 346.72 tCO2. [ABSTRACT FROM AUTHOR]

Introduction- This paper presents the study of the operational failure of a hydro-pneumatic system for the supply of water to a hospital facility. Objective- Determine the cause or causes for the interruption of the water supply of the hydro-pneumatic system to the building. Methodology- The hydraulic characteristic of the pipe system was drawn and compared with the hydraulic characteristic of the hydro-pneumatic system, verifying that it fully satisfied the load and flow requests demanded by the building. Given the presence of noises and vibrations in the suction pipe, the comparison of the required NPSH vs. the available NPSH determined that the current design of the suction pipe is the cause for the hydro-pneumatic system failure. Results- Three variants for the modification of the design of the suction pipe in order to eliminate the phenomenon of cavitation are proposed. This avoids putting into operation an auxiliary pump that increases energy consumption by 8,760 kWh/year with a cost of 1,839.6 $/year and the insecurity in the water service. Conclusions- The selected hydro-pneumatic equipment satisfactorily meets the requirements of the installation, except for the design of the suction pipe where the available NPSH is lower than the NPSH required at flow rates higher than 900 l/min, hence, producing the cavitation phenomenon and causing the output of system's service. [ABSTRACT FROM AUTHOR]

In this work the thermal-energetic schemes of the "14 de Julio" and "Antonio Sanchez" sugar mills belonging to the province of Cienfuegos are analyzed. In these enterprises Process Flow and Information Flow diagrams for its later simulation in the Termoazucar software (STA 4.1) were developed. With the help of reference software, base case modeling in these plants allowed to identify opportunities for improvement of thermal schemes. The implementation of them in the modeling of improved cases of these mills facilitated to be aware of the possibility of increases of 16% in the electricity sold to Eletroenergetic National System (SEN) in the "14 de Julio" sugar mill and 50% in the "Antonio Sanchez" sugar mill keeping both the same levels of ground. [ABSTRACT FROM AUTHOR]

This research deepens on the methods to the solution of the hyper static systems applicable for the assessment resistance of flywheels which are applied to a flywheel of a hammer mill. The results of the analytical methods were validated through a Finite Element Analysis, the results show differences minors than 10%. The equivalent strength in the rim is almost zero in the middle plane of the beam and increases as it moves away from it, and remains constant throughout the rays. It was also observed that in all the studied cases the equivalent tension decreases when the number of rays increases because of the flywheels stiffness increases. Also, graphics tools are obtained to a fast determination of the equivalent tension in the rim according to the number of rays and the speed of operation. [ABSTRACT FROM AUTHOR]