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Modern engineering problems, such as aircraft or automobile design, are often composed by a large number of variables that must be chosen simultaneously for better design performance. Normally, most of these parameters are conflicting, i.e., an improvement in one of them does not lead, necessarily, to better results for the other ones. Thus, many methods to solve multi-objective optimization problems (MOP) have been proposed. The MOP solution, unlike the single objective problems, is a set of non-dominated solutions that form the Pareto Curve, also known as Pareto Optimal. Among the MOP algorithms, we can cite the Firefly Algorithm (FA). FA is a bio-inspired method that mimics the patterns of short and rhythmic flashes emitted by fireflies in order to attract other individuals to their vicinities. For illustration purposes, in the present contribution the FA, associated with the Pareto dominance criterion, is applied to three different design cases. The first one is related to the geometric design of a clamped-free beam. The second one deals with the project of a welded beam and the last one focuses on estimating the characteristic parameters of a rotary dryer pilot plant. The proposed methodology is compared with other evolutionary strategies. The results indicate that the proposed approach characterizes an interesting alternative for multi-objective optimization problems.

The present work analyzed aspects of the fluid dynamics of the conventional concurrent dryer equipped with lifting flights and their influence on the performance of a rotary dryer. The drying of granulated fertilizers (GTSP) in a conventional concurrent rotary dryer was experimentally investigated and compared with a modified configuration known as the roto-aerated dryer. The main feature of this new dryer is the presence of an aerated system consisting of a central pipe (encased in the drum) from which a series of mini-pipes lead hot air directly to the particle bed, flowing at the bottom (without flights). The results obtained confirm the superior performance of the roto-aerated dryer due to its more effective gas-particle contact.

-This study analyzed the influence of the following parameters: overall volumetric heat transfer coefficient, coefficient of heat loss, drying rate, specific heat of the solid and specific heat of dry air on the prediction of a model for the fertilizer drying in rotary dryers. The method of parametric sensitivity using an experimental design was employed in this study. All parameters studied significantly affected the responses of the drying model. In general, the model showed greater sensitivity to the parameters drying rate and overall volumetric heat transfer coefficient.

The type of device that was built and studied in this research was used in 10,000 BC in Pompeii and used the strength of a man for its operation, currently this device is modernized and more efficient. The purpose of a ball mill is the fragmentation of solid materials into smaller granules, usually its use is limited to the grinding of non-plastic (or hard) materials. The objective of this work is to present the project construction and operation of a low cost ball mill for the fragmentation of materials, using in its development reusable materials. The motivation comes from the need for equipment to grind samples to be used in the Chemical Engineering laboratory, at the Federal University of Triângulo Mineiro (UFTM). The study of each type of mill was carried out accompanied by theoretical calculations for dimensioning and computer simulation so that the possible performance of the equipment can be closely seen. The different types of materials in each element of the equipment were also analyzed, looking for the best cost-benefit ratio in the project. The material used in the drum was polyvinyl chloride (PVC), the spheres were made of glass, the welded iron structure and the electric motor used, was an ergometric mat. The material used to be milled was phosphate rock, with different granulometries, which can be used, for example in the manufacture of phosphate fertilizers. The results were quite satisfactory, reaching a reduction of up to 96.95% of the initial size of the ground particles.