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This work studied the effect of external conditions on the drying kinetics of a thin layer of corn during convective drying. The density and the specific volume of the corn grain were reported and the desorption isotherms of the corn were determined at three temperatures and for a water activity from 0.1 to 0.9 using the static gravimetric method. Initially, a thin layer of corn about 7 mm thick with an initial moisture content of 45% (d.b) was investigated, and the external conditions were tested. Afterwards, a comparison between the experimental convective drying of a packed bed and a thin layer was performed under the same conditions. Finally, the values of equilibrium moisture contents, water activities and temperatures obtained were fitted using seven sorption models. It was found that the experimental desorption data exhibited type II behavior, according to Brunauer's classification. The GAB model was found as the most suitable semi-empirical model which was well suited to represent the desorption equilibrium moisture content of corn kernels in the suggested ranges of temperature and water activity. It can be concluded from the entropy–enthalpy compensation theory that the desorption process of the corn kernels is controlled by the enthalpy mechanism. [ABSTRACT FROM AUTHOR]

The objectives of the present research work are the three-dimensional computational analysis and predictions on double-diffusive natural convection in a cubic cavity filled with Cu–Al2O3/water micropolar hybrid nanofluid. The governing equations are carefully modified employing vorticity–vector potential formulation and are solved by the finite volume method. Performance enhancement of Cu–Al2O3/water micropolar hybrid nanofluid is judiciously compared with the Cu/water simple nanofluid. Besides, the influences of concentration of nanoparticles, Rayleigh number, buoyancy ratio, and micropolar vortex parameter on the flow field and heat transfer are critically analyzed. The results show that heat and mass transfer rates are lower for a micropolar nanofluid model when compared to the pure nanofluid model. The hybrid micropolar nanofluid displays more heat and mass transfer rates for thermal buoyancy-dominated zones when compared with traditional nanofluid. Conversely, the heat and mass transfer rates are decreased when using micropolar hybrid nanofluid for the solutal-dominated regime. The enhancement of micropolar viscosity parameter results in a decrease of average Nusselt and Sherwood numbers which are more perceptible in the thermal buoyancy-dominated flow. [ABSTRACT FROM AUTHOR]

This article presents a three-dimensional numerical investigation of heat and mass transfers and fluid flow in a cavity filled with an Al2O3/water micropolar fluid under uniform magnetic field. To solve the governing non-dimensional equations, Finite Volume Method (FVM) based on 3-D vorticity-vector potential formulation has been employed. The effects of various parameters such as buoyancy ratio (−2 ≤ N ≤ 0), Rayleigh number (103 ≤ Ra ≤ 105), Hartmann number (0≤ Ha≤ 60), nanoparticles volume fraction (0 ≤ φ ≤ 0.06) and micropolar material parameter (0≤ K≤ 5) on flow structure and on heat and mass transfers are presented. The results illustrate that for the micropolar nanofluid model, both heat and mass transfer rates and three-dimensional character of the flow are smaller when compared with the pure nanofluid model. It is also observed that increase and decrease in heat and mass transfer rates is experienced due to increase in Rayleigh number and Hartmann number, respectively. It is also noted that increase in vortex viscosity parameter reduces the average heat and mass transfer rates and is more evident when the magnetic field is imposed. Combined effects of magnetic field and nanoparticles volume fraction on heat and mass transfers are also explored. [ABSTRACT FROM AUTHOR]

This paper investigates the implementation of an analytical model to determine the porosity of a granular material during reactive and nonreactive sintering. A graphical interpretation of this model is proposed to calculate the porosity by comparing the experimental shrinkage curve with the ideal one. For the nonreactive sintering, some examples have been taken from the literature to illustrate the application of this method for two granular materials (alumina and zircon). In the case of reactive sintering, we have used our experiments to study the sintering behavior of magnesium hydroxide. The shrinkage curve was determined by dilatometer and the porosity was measured by helium pycnometer. The comparison revealed that the porosity calculated from the model is fully consistent with the porosity measurements in the both cases. [ABSTRACT FROM AUTHOR]

An inverse problem was considered to estimate electrical conductivity distribution for the electrical resistance tomography. This technique allows to control the internal parameters by reconstructing the distribution of electrical conductivity of liquid/solid suspension. As an analytical tool, the quadrupole method was used to solve the forward problem in order to simulate the sensors voltage evolution. The inverse problem is solved using the Levenberg–Marquardt method. A major source of uncertainty in tomographic inversion is the data error. The effect of the measurement errors on the stability of the solution was investigated. In order to find the current injection strategy which gives more information about the electrical conductivity, sensitivity analysis was carried out. The effect of Levenberg–Marquardt coefficient and initial value of the conductivity on the stability of the scheme was analyzed. The developed algorithm can be employed to rebuild the electrical conductivity which permits to go back to the physical parameters of the suspension. [ABSTRACT FROM AUTHOR]

A novel non-intrusive technique (stereo-correlation) was used to determine the apparent volume of a banana in convective drying condition. The volume was calculated using the 3D Digital Image Correlation method (3D-DIC), which provides the 3D shape of the banana during drying. The combination of this technique and mass measurement allows the calculation of the porosity using the model of Katekawa and Silva[1] and the graphical interpretation presented by Madiouli et al.[2] The banana shows an ideal shrinkage at the beginning of drying but stops shrinking at low moisture content, thus increasing the porosity up to 30-35%. The comparison of the experimental shrinkage and the calculated porosity with the experiments deduced from the literature enables us to conclude the effectiveness of the 3D-DIC technique as well as the porosity calculation model. [ABSTRACT FROM AUTHOR]

In this research work, design optimization and static analysis of a 3D printed based carbon PEEK (poly ether ether ketone, reinforced with carbon) polymer composite mono leaf spring was done using finite element analysis. Comparative study of leaf springs of a Dodge SUV car has been made by using 3D printed carbon PEEK. The main objective of this work is to optimize the design and material parameters, such as fiber diameter, fiber length, percentage volume of fibers and orientation angle of fibers in 3D printed based material with a mono polymer composite leaf spring. The effects of these parameters were studied to evaluate the deflection, bending stress, spring rate, stiffness and von Mises stress under different loading conditions. Furthermore investigation has been done to reduce the weight of leaf springs and claimed the 3D printed based leaf springs have better load carrying capacity. Thus an attempt has been made in this regard and we selected the 3D printed carbon PEEK in developing product design and material selection for minimum deflection and bending stress by means of response surface optimization methodology for an efficient leaf spring suspension system. The 3D printed carbon fiber polymer composite has three different percentage volume fractions such as 30%, 50%, and 60%. The selected carbon PEEK has 0°, 45°, and 90° fiber orientations. Finite element based analysis has been performed on 3D printed carbon PEEK material to conclude the optimized design parameters and best possible combination of factors affecting the leaf spring performance. [ABSTRACT FROM AUTHOR]