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Due to its importance and influence in the design of the blasting works taking into consideration the action of the explosion in the environment, in this work the main physical-mechanical properties of the embedding rocks are determined and the structure of the massif, constituted by gneisses, is analyzed at the Catoca mine. The density, volumetric mass, limit of resistance to simple static compression, limits of resistance to static traction and velocity of the longitudinal elastic waves were the properties determined in the massif; In the case of the structural study, with the use of the geological method, the systems and families of cracks were surveyed. As a result, the values of the aforementioned properties and the characterization of the different sectors of the mine according to their properties and cracking are offered, aspects of capital importance for the design of the blasting of the box rocks. [ABSTRACT FROM AUTHOR]

The usage of any material like structural element demands fundamentally the knowledge of its physical-mechanical properties, with the objective of knowing and take the maximum advantage of their properties and/or dismiss it if considered useless. This text presents the results obtained from the study of the physical-mechanical behavior of the bamboo from the species Guadua amplexifolia which grows North of the state of Veracruz, Mexico. 100 culms with an average height of 5.5 meters were used, taking into consideration the cutting methods and traditional seasoning. This research was supported in the methodologies employed in the consulted sources and the proposals from the Standards of the International Network for Bamboo and Rattan, as for physical and mechanical properties such as tests for compression, tension and cutting parallel to the grain and bending. As a scale the results for the species that grow in Monte Blanco, Veracruz, from the studies (Ordoñez, 1999) were taken into consideration. Average values from the last Efforts of failure for Compression, Cutting and Tension parallel to the bending as well for Flexion perpendicular to the fiber were obtained. It was compared with the scale and the registers obtained resulted similar, observing a very little variation in the results, possibly due to the anisotropy of the material, geographical location and age of the culms. For the Compression parallel to the fiber tests, failures were presented for longitudinal shear, due to the constitution of the material's fiber, diagonal tension and in a really low percentage flattening in the walls and faces of the test tube. For the Cutting test, failures were presented in the longitudinal shear, clearly visible because of the constitution of the material's fibers with considerable displacement at the walls of the test tube and in a lower percentage failure in longitudinal shear as well as in flattening. The species Guadua Amplexifolia showed similar properties to others studied in South America and are actually being used mainly in construction of housing, which leads to conclude, according to the properties showed here, that it may result feasible as an alternate structural material in construction. [ABSTRACT FROM AUTHOR]

The operating parameters of the belt conveyors which are presently operated in Cuban nickel industries do not tally with the physical-mechanical properties of the ore body in exploitation; which is why the load capacity and drive of this equipment are underused. To improve the efficiency of the conveyor, an experimental research was carried out in Ernesto Guevara Nickel Plant. An evaluation was completed on the physical mechanical properties of greater impact on the technological parameters of the conveyor. Grading composition, volumetric mass, swelling factor, moisture and natural and dynamic slop angle were analyzed for soft and homogenized samples of ore by applying traditional known methods such as weight, screening and volumetric differences. As a result, the variation ranges of the physical mechanical properties above mentioned were identified, thus obtaining functional relations among them that allow operating rates be established in real time and the most effective design be selected for the belt conveyor. [ABSTRACT FROM AUTHOR]

This research paper show the results of the dosage test carried out in the V-20 seeder machine using amaranth seed. A platform the results of the dosage test carried out in the V-20 seeder machine using amaranth seed. A platform test was built at the National Standardization Center for Agricultural Machinery (CENEMA) facilities, using the Mexican Norm: "Method for the evaluation of seeders and/or fertilizing machines with mechanical traction with dosimeter disk" and the Cuban 34-50 Norm "Grain seeder, a methodology for carrying out tests". The physical-mechanical properties, the dimensional characteristics of the seed related to the sowing process, and the work quality indexes for the seeder were determined. The mean values of seeds length, width and thickness were 1 448, 1 263 and 822 µm respectively, while the volumetric mass was 802 kg·m-3, with 7.4% of humidity and the 1000 seeds weight was 0.93 g. The results indicate significant differences among seeds dosed quantity averages in each exit due to the forward speed and number of bodies of the seeder. [ABSTRACT FROM AUTHOR]

The fact of being able to settle the good periods of storage to guarantee the maximum use to fruits and vegetables constitutes today a world premise leaving the alimentary crisis that actually crosses the world. The present work is focused in to determine the optimal storage period for guava, mandarin and tomato, as well as their different consumption stages during this period starting from the change in its physical-mechanical properties. For this study 70, 80 and 80 fruits were used, separated in samples of 10, 20 and 20 guavas, mandarin and tomatoes, which were stored in carton and wood boxes (for guavas) and plastic bags and carton boxes for mandarin and tomato kept at room temperature during 7, 12 and 12 days, respectively. For each fruit the weight lost, pH, SSC and firmness were determined, relating each property with storage time through excel calculation tool, supplied for Microsoft Office. The results show that the guava keep good properties to be consumed as fresh fruit during the first 4 days, and later it can receive another type of utility, on the other hand, the tomato from day 9 onward presents a high maturation index, thus after this day it could be industrially processed as juice, puree or another application and the orange conserves its properties for the consumption as fresh fruit during the whole analyzed period. The best results as for conservation were obtained when the fruits were stored in wooden boxes for the guava and in plastic bags for mandarin and tomatoes. [ABSTRACT FROM AUTHOR]

Given their specific use as source of natural insecticides of easy biodegradation, as well as other advantages in the improvement of saline soils, rescue of marginal lands and their exploitation in forestry, agro-forestry and forest, the cultivation of the Nim tree has been worldwide extended in many regions of Asia, África, Australia and Latin America, including Cuba. The harvest of Nim fruits becomes very difficult due to the great tall that reach these trees in a few years, being the mechanical harvest by shaking the main limbs or trunk a possible way of practical solution of this problem. The determination of the physical-mechanical properties of fruit-peduncle system is an indispensable stage during the investigations related with the determination of the parameters of the means for mechanical harvesting of agricultural products. The measurement of the main physical-mechanical properties is made with the aid of strain gages and digital images processing techniques. As a result of the investigation the main statistical indicators of a group of dimensional, inertial and elastic properties of the fruit-peduncle system, related with the mechanical harvest of Nim, were obtained. Also the bending moment, required for fruit detachment, is determined. [ABSTRACT FROM AUTHOR]

Chips of avocado wood (Persea americana Mill.) were pulped by means of conventional Soda and Kraft pulping processes. The pulps were bleached with an elemental-chlorine-free sequence O-D1-Eop-D2, pre-setting reaction conditions for the first chlorine dioxide stage (D1). The results show that during the chemical pulping process, avocado wood is easier to cook than other hardwoods such as eucalyptus. The avocado pulp also showed a very good bleachability, reaching brightness levels of up to 92% ISO compared to 84% for eucalyptus after the ECF bleaching sequence. The avocado Kraft pulps required more chemical input in the bleaching sequence than the Soda pulps. On the other hand, the physico-mechanical properties of the pulp were not notably reduced by the bleaching process, the Kraft pulp being stronger than the soda pulp. Strength properties of avocado are similar to those of eucalyptus; therefore this raw material constitutes a worthwhile choice for cellulosic fiber supply. [ABSTRACT FROM AUTHOR]