Moisture evolution, thermal properties and energy consumption of drying spent grain pellets from a blend of some cereals for small scale bio-energy utilization: Modelling and Experimental study

© 2022 Springer Nature Switzerland AG. This is the accepted manuscript version of an article which has been published in final form at https://doi.org/10.1007/s13399-022-02846-xA fixed bed convective dryer was used to assess the influence of drying temperature and geometry deformation on moisture and thermo-physical property evolution of solid fraction pellets (spent grain) from wet milling of cereal blends for bio-energy generation for small homes. The aim is to study the physical mechanism of drying the pellets that includes temperature and moisture behaviour, transport phenomena, the response rate to varying process conditions, drying time, and energy utilization which can be applied in the development of a fixed bed dryer for drying the pellets at a lower scale. The modified Cranck's diffusion model was used to study moisture loss by introducing shrinkage. The verification of the model gave the mean absolute error (MAE) for moisture content with shrinkage as 0.0366 - 0.1500 while for without shrinkage was 0.0729 - 0.1500 for 60- 80 oC. The effective moisture diffusivity with integrating shrinkage is lower than non- shrinkage though these values varied with drying time. Fitting the moisture ratio with the exponential drying curve equations shows that logarithmic equations were the best model for drying at 60 and 70 oC while Henderson and Pabis's model was better at 80 oC isothermal drying. Thermophysical analysis showed that the average specific heat capacity ranges from 5423.387 to 5198.197J/kgK while the thermal conductivity ranged from 0.115281to 0.136882W/mK at 60-80 oC. The energy and specific energy consumption ranged from 0.41 to 0.494 kWh and 108.39 to 119.29MJ/kg. The shrinkage ratios, effective diffusivity and energy and specific energy consumption were empirically presented as a function of moisture, temperature and or air velocity variations with a high degree of association.Peer reviewe

Diagnostic study of the roughness surface effect of zirconium on the third-order nonlinear-optical properties of thin films based on zinc oxide nanomaterials

Zinc oxide (ZnO) and zirconium doped zinc oxide (ZnO:Zr) thin films were deposited by reactive chemical pulverization spray pyrolysis technique on heated glass substrates at 500 °C using zinc and zirconium chlorides as precursors. Effects of zirconium doping agent and surface roughness on the nonlinear optical properties were investigated in detail using atomic force microscopy (AFM) and third harmonic generation (THG) technique. The best value of nonlinear optical susceptibility χ(3) was obtained from the doped films with less roughness. A strong third order nonlinear optical susceptibility χ(3) = 20.12 × 10−12 (esu) of the studied films was found for the 3% doped sample

Influence of Roughness Surfaces on Third-Order Nonlinear-Optical Properties of Erbium-Doped Zinc Oxide Thin Films

ABSTRACT Zinc oxide (ZnO) and erbium-doped zinc oxide (ZnO:Er) thin films were deposited on heated glass substrates using the spray pyrolysis technique. Third-order nonlinear-optical properties of the thin films have been investigated using the third harmonic generation (THG) at wavelength of 1064 nm in picosecond regime. The dependence of third-order nonlinear susceptibility and transmission characteristics on the thin films roughness has been evaluated. Third-order nonlinear optical susceptibility (χ(3)) values of the studied materials were in the remarkable range of 10−2 esu. The morphologic properties of the deposited films have been analyzed using x-ray diffraction (XRD) and atomic force microscopy (AFM) and the luminescence properties by cathodoluminescence (CL). A correlation between optical properties and structural properties is given

Roughness effect on photoluminescence of cerium doped zinc oxide thin films

Undoped and cerium doped zinc oxide thin films have been prepared by spray pyrolysis technique. The influence of Ce as doping agent on the optical and nonlinear optical properties was carefully investigated using transmission, X-ray diffraction, photoluminescence, atomic force microscopy (AFM), and third harmonic generation (THG). It has been found a deep correlation between the surface roughness and the optical properties. In fact the roughness deteriorates the luminescence and nonlinear response, in a sense that the highest luminescence intensity and nonlinear susceptibility χ(3) are obtained for the smoothest layer.Doped layers are characterized with a high visible luminescence, attributed to cerium transitions, and susceptibilities in the range of 6.38 × 10−13 esu

Commandabilité d'un système dynamique linéaire

Guérin J.-P., Lamrani B., Oudet B. A. Commandabilité d'un système dynamique linéaire. In: Revue économique, volume 26, n°5, 1975. pp. 839-847

Influence of strontium substitution on the dielectric properties of Ca(1−x)SrxTi0.9Zr0.1O3 solid solutions

International audienceA conventional solid-state reaction has been used to synthesize the perovskite Ca(1 − x)SrxTi(1 − y)ZryO3 (y = 0.1). The aim of this study is focused on the development of new materials with complex perovskite structure and on their dielectric property improvement. The temperature and substitutional ratio effects on the different phase evolutions is investigated by X-ray diffraction (XRD) and scanning electron microscope observations. These ceramics sintered at 1500 °C, present a density higher than 95% and their dielectric properties are significantly affected by the substitution. The CaTiO3 ceramic present a relative permittivity of 190 and the temperature coefficient of the permittivity of − 1828 ppm/C°. The substitution with zirconium (for x = 0 and y = 0.1: Σ = 145; |Σ = − 917 ppm/C°). Both permittivity and temperature coefficient values decrease; however, an opposite effect is observed when substituting with the strontium. With increasing an x value and maintaining a y value constant (y = 0.1), the dielectric constant increases and the temperature coefficient remains constant. Therefore, the dielectric properties of CaTiO3 ceramics are improved with the combined substitution

Influence of strontium substitution on the dielectric properties of Ca(1−x)SrxTi0.9Zr0.1O3 solid solutions

International audienc

Global hydrogen development - A technological and geopolitical overview

International audienceHydrogen is an energy carrier that will certainly make an important and decisive contribution to the global energy transition and lead to a significant reduction in greenhouse gas (GHG) emissions over the coming decades. It is estimated that 60% of GHG emission reductions in the last phase of the energy transition could come from renewables, green hydrogen and electrification based on green energy development. Coordinated efforts by governments, industry and investors, as well as substantial investment in the energy sector, will be required to develop the hydrogen value chain on a global scale. This paper summarizes the technical and technological advances involved in the production, purification, compression, transportation and use of hydrogen. We also describe the roadmaps and strategies that have been developed in recent years in different countries for large-scale hydrogen production