Desempenho agronômico, bromatológico e estabilidade fenotípica de sorgo silageiro em Uberlândia - MG

Sorghum (Sorghum bicolor (L.) Moench) is a good alternative to be used as silage, especially in places with water scarcity and high temperatures, due to their morphological and physiological characteristics. The appropriate management, as the ideal seeding time, interferes both productivity and the quality of silage. The work was conducted with the objective of evaluating the agronomic and bromatological performance of varieties and hybrids of silage sorghum and their phenotypic stability in two seasons, season and off-season, in the city of Uberlândia, Minas Gerais. The experiments were performed at Capim Branco Experimental Farm of Federal University of Uberlândia (UFU), located in the referred city. There were two sowing dates in the same experimental area, off-season (March to June 2014) and season (November 2014 to March 2015), and the varieties and hybrids were evaluated in both situations. The design was a randomized block with 25 treatments (hybrids and varieties of sorghum) and three replications. Agronomical and bromatological data were subjected to an analysis of variance; averages were grouped by Scott-Knott test at 5% of probability, through Genes computer program; and to estimate the stability, it was opted for Annicchiarico method. The flowering of cultivars, dry matter productivity, plant height, Acid Detergent Fiber (ADF), Neutral Detergent Fiber (NDF) and Crude Protein (CP) are affected by the environment and the variety. Regarding productivity and quality of the fiber, SF11 variety was superior, independent of the rated environment. In relation to the performance stability of dry matter, the varieties SF15, SF11, SF25, PROG 134 IPA, 1141572, 1141570 and 1141562 were highlighted. For the stability of the quality of fibers (FDA and FDN), the variety 1141562 stood out. The environment reduces the expression of characters “days of flowering”, “plant height” and “productivity of dry matter of hybrids”. From the 25 hybrids analyzed for productivity and stability of dry matter performance, seven were highlighted, regardless of the rated environment: Volumax commercial hybrid and experiments 12F39006, 12F39007, 12F37014, 12F39014, 12F38009 and 12F02006.

Influência da utilização do fluido de corte com adição de grafeno na temperatura de usinagem e formação de rebarba no processo de micro fresamento

As time passed, humanity needed the development of new materials used in various activities. High strength materials such as titanium and Inconel for example, had been studied because they are widely used for implants in biomedicine, as well as their use in aerospace and automotive industries. Because of its thermal and mechanical properties, these materials are considered difficult to machine, promoting a rapid wear of cutting tools, primarily caused by the high temperatures in machining. With the development of new materials has emerged the need of developing new manufacturing processes. One of today’s innovative processes is the micro-manufacturing. Being a process with a defined cutting tool geometry, burr formation is a constant and undesirable phenomenon formed during the machininig process. Being detrimental to the manufacturing process, overspending deburring operations are constantly employed leading to increase the aggregate cost to the manufactured material. Assembly components are also impaired if there is no control of the burr, with consequences including the disposal of components due to the occurence of this phenomenon. This paper presents the study of micro-milling Inconel 718, investigating influential parameters in the formation of burrs in order to minimize the occurrence of this phenome non. Different feed rates per tooth and cutting speed are evaluated, and different cutting fluids with different methods of applying the fluid. Adding graphene to cutting fluids was considered as a variable to be investigated, which is considered an excellent solid lubricant, in addition to increasing the thermal conductivity of the cooling solution (AZIMI; MOZAF FARI, 2015). The micro-milling temperature was evaluated in the present work. It was observed a new phenomenon that causes the machined surface temperature decreases below room temperature when using the solution water + oil. This phenomenon is explained in further chapters. In order to unravel this phenomenon, a new test was proposed and, from this test, it can be concluded, comparatively, which cutting fluid has a better cooling property.Using cutting fluid with different thermal properties has shown influence when analy zing burr formation and reducing machining temperature.