CALCULATION OF CULVERTS UNDER ROAD EMBANKMENTS USING THE SEMI-ANALYTICAL FINITE ELEMENT METHOD

The article discusses the methodology for calculating corrugated metal structures used as culverts based on the semi-analytical finite element method. The calculation is carried out according to a non-deformable scheme using the load dependences obtained on the basis of the structural mechanics of bulk solids. Significant differences in the nature of the stress-strain state of corrugated structures in comparison with smooth shells is revealed.

BATCHPUMP: AN ALTERNATIVE TO CONVENTIONAL BLOW TANKS

The pursuit of better energy efficiency solutions is a constant subject. Here we present a number of results obtained during the development of an industrial equipment; a bulk solids feeder called Batchpump. With the proposal of being an alternative to the conventional blow tanks, having as main differentials: energy efficiency; simpler installation; lower dimensions; and lower cost of production. In this work there is presented the results obtained for both the Batchpump and a conventional blow tank applied to a pneumatic conveying system, with limestone powder, on a pipeline with 133m of total length, with an inlet pressure of 4 bar, the Batchpump obtained results of conveying rate being 25% lower and the air consumption being 30% lower validating the initial hypothesis: to consume less energy with comparable transport rate. We present in the results the data in steady state transport cycle in dense phase regime.

Adjustment of the PID Gains Vector Due to Parametric Variations in the Plant Model in Terms of Internal Product

The tuning of the gains of a controller with proportional-integral-derivative (PID) actions has been prevalent in the industry. The adjustment of these gains in PID controllers is often determined by classical methods, such as Ziegler-Nichols, and trial and error. However, these methods fail to deliver satisfactory performance and often do not meet specific project demands because of the inherent complexity of industrial processes, such as plant parameter variations. To solve the tuning problem in highly complex industrial processes, a controller adjustment method based on the internal product of PID terms is proposed, and a propagation matrix (PM) is generated by the numerator coefficients of the plant transfer function (TF). In the proposed method, each term of the PID controller is influenced by each of the numerator and the denominator coefficients. Mathematical models of practical plants, such as unloading and resumption of bulk solids by car dumpers and bucket wheel resumption, were employed to evaluate the proposed method. The obtained results demonstrated an assertive improvement in the adjustment gains from PID actions, thereby validating it as a promising alternative to conventional methods.