Carlos Alberto Chaves

Barras de Diamante Sintético: Atendendo as Futuras Necessidades na Indústria

This article aims to conduct a study on the benefits of replacing natural Diamonds by synthetic diamond rods in the production of dressers. This research seeks to introduce a new material in the construction of dressers, identifying through the QFD methodology (Quality Function Deployment) what are their main advantages in its use. The purpose of using QFD for this study is that the method can be defined as a systematic process that helps to identify the characteristics that a product must have to satisfy the customer. QFD can translate customer requirements by determining the functions, processes and raw materials of a product for the company to establish technical development goals for improved product performance. The composition of the service data and the application of QFD method for product development and the results show that the introduction of synthetic diamond bars can satisfy the basic and specific needs of industry in the dressing operation of wheels.

Notes on Steady Natural Convection Heat Transfer by Double Diffusion From a Heated Cylinder Buried in a Saturated Porous Media

This paper aims to present numerical solutions for the problem of steady natural convection heat transfer by double diffusion from a heated cylinder buried in a saturated porous media exposed to constant uniform temperature and concentration in the cylinder and in the media surface. A square finite domain 3 x 3 and acceptance criterion converged solution with an absolute error under 1 x 10(-3) were considered to obtain results presented. The Patankars power law for approaching of variables calculated T, C, and phi also was adopted. In order of method validation, an investigation of mesh points number as function of Ra, Le, and N was done. A finite volume scheme has been used to predict the flow, temperature, and concentration distributions at any space from a heat cylinder buried into a fluid-saturated porous medium for a bipolar coordinates system. Examples presented show that the differences in the flow distribution caused not only when Rayleigh number range is considered but also when Lewis number range is considered. Further, increase in the Rayleigh number has a significant influence in the flow distribution when the concentration distribution is considered. Steady natural convection heat transfer by double diffusion from a heated cylinder buried in a saturated porous medium is studied numerically using the finite volume method. To model fluid flow inside the porous medium, the Darcy equation is used. Numerical results are obtained in the form of streamlines, isotherms, and isoconcentrations. The Rayleigh number values range from 0 to 1000, the Lewis number values range from 0 to 100, and the buoyancy ratio number is equal to zero. Calculated values of average heat transfer rates agree reasonably well with values reported in the literature.