Magneto convective instabilities driven by internal uniform volumetric heating

The problem of volumetric thermal action on a moist porous medium is considered. Numerical solution, the influence of fluid mobility on the dynamics of the heat and mass transfer process is analyzed. It is established that fluid mobility leads to a softer drying regime. It is shown that in low-permeability media, the fluid can be assumed to be stationary.

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Convective instabilities in ferrofluids with internal structures

Magnetohydrodynamics ◽

10.22364/mhd.40.3.3 ◽

2004 ◽

Vol 40 (3) ◽

pp. 251-268

Keyword(s):

Convective Instabilities ◽

Internal Structures

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Microwave-Assisted Preparation of Luminescent Inorganic Materials: A Fast Route to Light Conversion and Storage Phosphors

Molecules ◽

10.3390/molecules26102882 ◽

2021 ◽

Vol 26 (10) ◽

pp. 2882

Author(s):

José Miranda de Carvalho ◽

Cássio Cardoso Santos Pedroso ◽

Matheus Salgado de Nichile Saula ◽

Maria Claudia França Cunha Felinto ◽

Hermi Felinto de Brito

Keyword(s):

Rapid Heating ◽

Inorganic Materials ◽

Rapid Screening ◽

Conventional Heating ◽

Quantum Yields ◽

Microwave Assisted Synthesis ◽

Volumetric Heating ◽

White Leds ◽

Microwave Assisted ◽

And Storage

Luminescent inorganic materials are used in several technological applications such as light-emitting displays, white LEDs for illumination, bioimaging, and photodynamic therapy. Usually, inorganic phosphors (e.g., complex oxides, silicates) need high temperatures and, in some cases, specific atmospheres to be formed or to obtain a homogeneous composition. Low ionic diffusion and high melting points of the precursors lead to long processing times in these solid-state syntheses with a cost in energy consumption when conventional heating methods are applied. Microwave-assisted synthesis relies on selective, volumetric heating attributed to the electromagnetic radiation interaction with the matter. The microwave heating allows for rapid heating rates and small temperature gradients yielding homogeneous, well-formed materials swiftly. Luminescent inorganic materials can benefit significantly from the microwave-assisted synthesis for high homogeneity, diverse morphology, and rapid screening of different compositions. The rapid screening allows for fast material investigation, whereas the benefits of enhanced homogeneity include improvement in the optical properties such as quantum yields and storage capacity.

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Study of color kinetics of banana (Musa cavendish) under microwave drying by application of image analysis

Food Science and Technology International ◽

10.1177/1082013220981334 ◽

2020 ◽

pp. 108201322098133

Author(s):

Sagar Nagvanshi ◽

Subbarao Kotra Venkata ◽

TK Goswami

Keyword(s):

Microwave Power ◽

Vision System ◽

Power Level ◽

Microwave Drying ◽

Slice Thickness ◽

Order Kinetic ◽

Drying Time ◽

Volumetric Heating ◽

Kinetics Of ◽

Microwave Power Level

Microwave drying works on the volumetric heating concept promoted by electromagnetic radiation at 0.915 or 2.450 GHz. In this study, banana ( Musa Cavendish) was taken as the sample and treated under microwave drying. The effect of two process variables, namely slice thickness (2, 3.5, and 5 mm) and microwave power (180 W, 360 W, and 540 W), were studied on drying kinetics and color kinetics. It was observed that the inverse variation relationship exists between drying time and microwave power level while drying time and slice thickness exhibited a direct variation relationship. A Computer Vision System (CVS) was developed to measure the color values of banana in CIELab space using an algorithm written in MATLAB software. Once the color parameters were obtained, they were fitted in First and Zero-order kinetic models. Both models were found to describe the color values adequately. This study concludes that microwave drying is a promising dehydration technique for banana drying that reduces the significant time of drying. Application of CVS is an excellent approach to measure the surface color of banana.

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