Modeling and experimental study of hydrodynamic and drying characteristics of an industrial rotary dryer

The purpose of this work was to analyze the hydrodynamic and drying aspects of a rotary dryer used in a fertilizer industry. A set of equations to predict the solids holdup in the flights, the length of fall, the residence time of particles and the drying variables was evaluated by comparison to experimental measurements performed in an industrial rotary dryer of the Copebras Fertilizer Company, located in Catalão, state of Goias, Center-west of Brazil. Because of precise estimations, these equations may be used to design and predict the solids cascading behavior in industrial rotary dryers. Despite larger deviations, reaching 20%, the drying model can also be used for design calculations and process simulations

High temperature measurement and characterisation of piezoelectric properties

Currently available high performance piezoelectric materials, predominantly based on lead zirconate titanate (PZT), are typically limited to operating temperatures of around 200 °C or below. There are many applications in sectors such as automotive, aerospace, power generation and process control, oil and gas, where reliable operation at higher temperatures is required for sensors, actuators and transducers. New materials are being actively developed to meet this need. Development and application of new and existing materials requires reliable measurement of their properties under these challenging conditions. This paper reviews the current state of the art in measurement of piezoelectric properties at high temperature, including direct and converse piezoelectric measurements and resonance techniques applied to high temperature measurements. New results are also presented on measurement of piezoelectric and thermal expansion and the effects of sample distortion on piezoelectric measurements. An investigation of the applicability of resonance measurements at high temperature is presented, and comparisons are drawn between the results of the different measurement techniques. New results on piezoelectric resonance measurements on novel high temperature piezoelectric materials, and conventional PZT materials, at temperatures up to 600 °C are presented