Papers by Keyword: Drying

Abstract: Drying also known as dehydration is commonly used as a unit operation in herbs manufacturing industry to preserve the food product by removing the moisture content in the herbs. Unfortunately, most drying process degraded the product quality because the feedstock is exposed to a very high temperature within a long period of time by using conventional oven Therefore this research has focused on the alternatives technique in overcoming the degradation of nutrients by applying the irradiation concepts. The objectives of this research were to investigate the effect of drying onto the physical properties of Aquilaria Malaccensis leaves by using fabricated far-infrared dryer. The experiments were conducted at various temperature ranging from 40, 50 and 60°C. The color difference and the moisture content of the leaves before and after drying were examined. The color measurements data shows that at 60°C, the brightness and the chroma were the highest. On the other hand, the hue angles were the highest for 60°C when the time was reached 100 minutes.

Abstract: This paper focuses some fundamental aspects of combined convective and microwave drying of prolate spheroidal solids. A transient mathematical modeling based on the diffusion theory (mass and heat balance equations) written in prolate spheroidal coordinates was derived and the importance of this procedure on the analysis of the drying process of wet porous solid, is also presented. Results pointed to the behavior of the moisture migration and heating of the solid with different aspect ratio. Solids with higher area/volume relationships dry and heat faster.

Abstract: This work presents a theoretical and experimental study of banana drying. Whole banana were peeled, sliced manually and dried in an oven at constant drying condition (40 and 70°C). Drying, heating and shrinkage lumped models were proposed and fitted to experimental data. Non-linear regression analyses were done to verify the consistence of the models to predict the experimental data. Results revealed which air temperature affect significantly moisture removal, heating and shrinkage of banana slices. Drying, heating and dimensions variations were increased when higher temperature and area/volume relationship are used. The fitted results presented good agreement with experimental data.

Abstract: This work presents a theoretical and experimental study of drying of sisal fibers. The fibers were submitted to drying in oven with forced air circulation at temperatures ranging from 50°C up to 90°C. Drying and heating lumped models were proposed and fitted to the experimental data. Non-linear regression analyzes were performed to verify the consistency of the models to predict the experimental data. It was verified that the curves of moisture loss and temperature of the sisal fibers were influenced by the drying-air temperature, showing a gradual variation with the drying time, being more accentuated in the higher temperatures of the drying-air. The fitted models presented good agreement with the experimental data.

Abstract: Drying is a simultaneous process of heat and mass transfer and dimensional changes. In recent years, cyclones have been used as a modern drying technology. In this sense, this research proposes a numerical study to describe drying of sugarcane bagasse, using the cyclone as dryer. Herein, it was adopted the Eulerian-Lagrangian model in steady state. The Reynolds stress model was considered to describe turbulence of the gas phase, while a transient lumped model was used to describe heat and mass transfer on the particulate phase (sugarcane bagasse). Particles were considered with irregular shape, composed of a binary mixture (solid part and water). The solution of the proposed model was obtained using the commercial software Ansys CFX 12. Results of the moisture content, temperature, dimension variation, and paths of particles, as well as velocity, pressure, and temperature distributions of the gas phase inside the cyclone are presented and analyzed. It has been found that the obtained components for axial and tangential velocity inside the cyclone are in good agreement with experimental data available in the literature, and that the drying kinetics, heating, dimensional variations, and residence time of particles are affected by the velocity of the gas phase, velocity of the particles, and the flow direction of gas and particles at the entrance of the feed duct.

Abstract: There are numerous studies on the application of ceramic materials, such as bricks, in the various engineering and manufacturing fields. Ceramic bricks are manufactured from humidified clay and are classified as structural ceramics. When exposed to drying the process is not precisely controlled, defects such as cracks, deformations and warping can arise, which compromise the final physical and structural properties of the product. Seeking to solve the procedure through simulations, this work presents a numerical study on a brick drying. A three-dimensional transient model is presented to predict the temperature of the holed ceramic brick and the distribution of the humidity content in a drying situation inside a temperature controlled oven, the heat transfer and mass phenomena are present. As simulations were done in the ANSYS CFX^® program, which uses the Finite Volumes Method and presented satisfactory results when compared with the experimental works.

Abstract: Analytical prediction of capillary pattern collapse is done by balancing the capillary forcesdue to the curved liquid interface with the elastic forces due to the bending of the structure. This paperintroduces a more realistic model where there is an array of repeating lines and spaces, and compares itto the traditional model of two single lines with liquid-filled space in between. This paper also includesthe influence of a non-vertical sidewall angle, and its effect on the overall elastic force. Results showthat the repeating structures and non-vertical sidewall angles both predict a higher critical height beforecollapse occurs compared to the traditional model.

Abstract: This work discusses pattern collapse-free drying by application of a sacrificial polymer during the semiconductor wafer cleaning process. The sacrificial polymer is dispensed onto the wafer, displacing the rinse liquid and subsequently dried to form a solid polymer fill within the patterned structure, providing both mechanical support and a means for dry polymer removal by either plasma or thermal exposure. Polymer film thickness, gap fill capability and removal rate are explored for plasma ashable and thermally removable polymer families.

Abstract: Recently, a surface energy reduction process (SERP) for stiction-free drying is used for a high aspect pattern structure like shallow trench isolation (STI). The key technology of SERP is trimethylsilyl (TMS) groups termination of the device surface. To explain the electrical influence of TMS groups was found acceptable by measuring the planar capacitor flat-band voltage shift, and the threshold voltage characteristics of 1x-nm node MOS transistors.

Abstract: Microalgae-cianobacteria Arthrospira (trade name Spirulina) are cultivated worldwide due to its nutritional and therapeutic qualities. The aim of this review is to summary production parameters affecting quality of Arthrospira. The biochemical composition of microalgae foodstuff is mostly determined by growing conditions, e.g. growth media, light intensity, temperature as well as drying method and conditions. This review showed that prospective directions for optimization of costs to cultivate Arthrospira indoors are: effective use of light, e.g., using effective artificial light sources like light emitting diodes (LED) in color with regards to necessary component in Arthrospira; mixotropic growth using growth media from food processing by-product/waste; and selection of Arthrospira strain according to available temperature. Common methods of algae drying for food and nutraceuticals are solar drying, convective drying, spray drying, lyophilization. The drying method and regime can greatly affect the amount of biologically active compounds and organoleptic quality.