Enfoque UTE

pp. 1 - 15

Authors: Juan G. Paredes Salinas, Cristian F. Pérez Salinas, Christian B. Castro Miniguano

Studies of composite materials play an important role in engineering, materials, metallurgy and mechanical applications. Polymer reinforced fibers are widely used in the automotive and aeronautical industry because of their benefits such as low cost, noise control, low weight and ease of processing. The objective of this research was to prepare a composite based on 375 (FV) glass fiber with additions of natural cabuya (CF) fiber in laminations of short natural fiber of cabuya (FCO1-30%) and long fiber of the same (FL-30%). The results showed a better mechanical tensile behavior in 7.7% compared to the material commonly used. It was observed that 30% long fiber in a layer order, FV+FC+FV, is a potential reinforcement of the alternative hybrid material for automotive applications. In addition, a balanced reinforcement organization, FV+FC, and micro structural adhesion with the polymeric reinforcement matrix (RP) were evidenced by scanning microscopy. The results of tensile stress and axial deformation of the best combination of composite material, FL-30%, are validated using the finite element method (MEF).

pp. 28 - 40

Authors: Sonia Rosero, Norma Erazo, Miguel Guallpa, Marlene Usigña

The research consisted in evaluating four biostimulants and three substrates for the propagation of Vallea stipularis L.f. in greenhouse conditions. The biostimulants corresponded to: plant hormone rooting (B1), agrohormones 10-10-10 (B2), ESPOCH biostimulant (B3) and Gron Gibb (B4). The substrates consisted of: 50% black soil + 25% peat + 25% sand (S1); 50% black soil + 25% peat + 25% humus (S2) and 50% peat + 50% humus (S3). For the study, it was used a randomized complete design (RCD) with factorial arrangement, it was determined the coefficient of variation and the Tukey test at 5% for the separation of means. The application of the biostimulants in the substrates was done at the time of planting. According to the results obtained, the best biostimulants corresponded to B1 (plant hormone rooting), applied in the seeds for 15 minutes, with which the highest emergency percentage was obtained (70.96%); with biostimulant B2 (agrohormones 10-10-10), applied for five minutes it was obtained 70.67% and with B3 (Gron Gibb) 70.37%. The best substrate for emergence of plants was: 50% peat + 50% humus) with 73.67% of emergence, where the highest plant height and root length were achieved, instead, the ESPOCH biostimulant (microoganisms) reported a 67, 11% emergency.

pp. 56 - 71

Authors: Luis Juiña, Víctor Hugo Cabrera, Salvatore Reina

In the following project, the theory of constraints was applied in order to implement a manufacture CAD-CAM system into the metal mechanic industry processes of polymers injection and blown of polymers. The research showed that the manufacture of the mold with the engraving took 223,17 hours. In the workflow for the manufacture of the mold, a restriction was found in the outsource service of CNC. It took 120 hours of the whole process and represent the 51,47 % the total time of tooling manufacturing. There is also a constraint found in the design time. It was 60 hours that corresponds to 26,88 % of the overall time. In order to reduce the time, a modern system of design in 3D and CAM was established to improve the model process of design and manufacture. A simulation by computational resource was applied to the plastic. The design was changed from 2D to 3D. The implementation was focused in the design. A software was installed to improve the speed of modeling methods with reliable information. In the manufacture of molds, a new CNC machine was acquired with three simultaneous axes to eliminate the outsource service. By acquiring the design system, the working time was diminished in 79% and regarding to the CNC process, the working time was improved in 88%.