Modeling of Coupled Heat and Mass Transfer in a Trapezoidal Porous Bed on a Grid

We investigate heat and mass transfer in an isosceles trapezoidal cavity, filled with charcoal considered as a granular porous medium. The Darcy-Brinkman-Forchheimer flow model is coupled to the energy and mass equations with the assumption of non-thermal equilibrium. These equations are discretized by the finite volume method with an offset mesh and then solved by the line-by-line method of Thomas. The coupling between pressure and velocity is obtained by Semi-Implicit Method for Pressure Linked Equations. (SIMPLE) algorithm. The results show that the temperature in the cavity increases when the inclination angle of the sides walls decreases. The 15° inclination is selected as being able to offer better thermal performance in the cookstove combustion chamber.

Performance of the Boost Chopper, Comparative Study between PI Control and Neural Control to Regulate Its Output Voltage

In this study, we investigate the performance of a boost converter regulating its output voltage using two control methods: Proportional-Integral (PI) control and neural control. Both methods are implemented on a simulation platform (Matlab/Simulink) and evaluated in terms of accuracy, response speed, and robustness to disturbances. Indeed, the output voltage of converters exhibits imperfections that require a control method to optimize efficiency when applying a variable load. Results show that neural control offers superior performance in terms of accuracy and response time, with faster and more precise regulation of the output voltage. On the other hand, PI control proves to be more robust against disturbances. These findings can help guide the selection of the appropriate control method for a boost converter based on the specific requirements of each application.

Experimental Study of a Modified Icaro Solar Dryer: The Case of Coffee Drying

Food losses in the developing country are thought to be 50% of the fruits and vegetables grown and 25% of harvested food grain. Food preservation can reduce wastage of a harvest surplus, allow storage for food shortages, and in some cases facilitate export to high-value markets. Drying is one of the oldest methods of food preservation. Drying makes produce lighter, smaller, and less likely to spoil and helps to minimize the moisture content in coffee beans as high moisture content during storage is certain to ruin the taste and appearance of coffee. This work presents the results of an experimental study of forced convection drying of coffee cherries in a modified Icaro solar dryer. The study aims to validate the numerical models developed for further research. The experimental tests envisaged also aim to determine the mass loss curves of the product by fixing or calculating its initial mass (1 kg), its initial water content (70%), the ambient temperature, the drying airflow (0.02 m3.s-1 to 0.09 m3.s-1) and the exchange coefficients. The influence of these aerothermal parameters on the drying time of a most commercialized coffee variety (Robusta) was studied. Finally, the results revealed an increase in the efficiency of the heat transfer air and a reduction in the water content of the coffee cherry from 70% to 9.87%, after 30.2 hours.

Jonzac Thermal Spring Water Reinforces Skin Barrier Function of Human Skin and Presents a Soothing and Regenerating Effect

The skin is a formidable physical and biological barrier which communicates continuously with the outside of the body. And the stratum corneum, the outermost layer of human epidermis, plays a central role in the interaction between the cutaneous tissue and the external environment. The horny layer, and more generally the whole skin layers, avoid the penetration of harmful exogenous agents, produce molecules named anti-microbial peptides which impact the composition of the cutaneous microbiota, regulate the internal corporal temperature, avoid the water loss from the inside of the body and constitute an incredible efficient anti-oxidant network. Nevertheless, nowadays, the skin is more and more solicited by the different elements of the cutaneous exposome, including atmospheric pollution and solar radiations, which can cause a dramatic acceleration of the skin ageing process. As a consequence, due to the multifunctional protective role of the skin, during the recent decade the cosmetic industry invested massively in the development of new raw materials and end-products (dermo-cosmetics) able to preserve an optimal state of the skin regarding the external environment. Based on their physical-chemical properties thermal spring waters, which are extremely rich in inorganics ions, are interesting and powerful candidates to be part, as integral component, of new efficient dermo-cosmetic formulations dedicated to protect the skin from the external stimuli. The aim of the present work was to investigate and characterize the activity of Jonzac thermal spring water on the skin. Using different models, we proved for the first time that Jonzac thermal spring water reinforces the barrier function of the skin by modulating the expression of key markers including filaggrin and human beta defensin 2 on ex vivo human skin. The ex vivo and in vivo hydration activity, by Raman spectroscopy and corneometry respectively, has been also demonstrated. We have also shown that Jonzac thermal spring water ameliorates significantly the cutaneous microrelief in vivo. To conclude, we characterize the soothing effect of Jonzac thermal spring water by the analysis of histamine release in Substance P treated skin explants and by measuring the redness of the skin following UV exposure of the skin in vivo. We observed that both parameters decreased following a preventive treatment of the skin with Jonzac thermal spring water. Taken together our results indicate that Jonzac thermal spring water is a promising and powerful dermo-cosmetic which can be used to preserve an optimal state of the cutaneous tissue.

Physicochemical and Biochemical Composition of Balanites aegyptiaca Seed and Seed Oil from Burkina Faso

In Burkina Faso, the seeds of Balanites aegyptiaca have been considered to be potentially high lipid, protein and mineral sources but seem to be neglected and sometimes unknown by communities. This study aims to complete data on seed oil and detail on amino acids and minerals composition of the seed of B. aegyptiaca for better use. Physicochemical parameters such as moisture and ash content, saponification index, iodine, acid value, peroxide value and the melting point were determined. Seed oil triglycerides, fatty acids and amino acids have been estimated throughout this study. The moisture and ash content were 3.70% ± 0.1% and 2.90% ± 0.2%, respectively. The saponification and iodine values were respectively 181.96 ± 0.4 mg KOH/g of oil and 104.86 ± 0.6 g of iodine/100 g of oil. Polyunsaturated fatty acid content (50.94%) was the most important. Triglyceride (LLO, 22.4%) was the major triglyceride. 9 essential amino acids and 9 non-essential amino acids were identified. Phenylalanine (11697.82 ± 0.00 mg/kg) was the most important essential amino acid. The content of 21 minerals was determined and the most important was potassium (9323.13 ± 0.01 mg/kg). Ca/P, Ca/Mg, Ca/Mg and Na/K ratios were 0.34;1.18;0.04 and 0.19 respectively. B. aegyptiaca seed oil is a source of multiple nutritional values and can be used by the population for multipurpose.

热键合制作Yb：Y3Al5O12／Y3Al5O12复合晶体

采用热键合技术制备了Yb:Y_3Al_5O_(12)/Y_3Al_5O_(12)(Yb:YAG/YAG)复合晶体,对复合晶体进行了结构表征和键合质量检测.利用光学显微镜和扫描电镜观察了复合晶体横截面的形貌;在偏光显微镜下观察键合区域的应力,利用干涉条纹来表征复合晶体的光学均匀性;通过红外透过光谱的测量来检测复合晶体的键合质量.实验结果表明:热键合技术制备的Yb:YAG/YAG复合晶体键合界面处无界面缺陷,不存在复合界面空间过渡层,光学均匀性良好.

Comparative Study between the PID Regulator and the Fuzzy Regulator Applied to the Operation of a Brushless DC Motor

This paper presents the results of research on speed regulation of a brushless DC motor. This is mainly a comparative study between a PID regulator and a fuzzy regulator applied to the operation of this type of engine in order to find the best control. The BLDC engine must operate under various speed and load conditions with improved performance and robust and complex speed control. Because of this complexity, the traditional PID command encounters difficulties in controlling the speed of a BLDC. Another control technique is currently developing and is producing good results. This is the fuzzy controller that handles process control problems, that is, managing a process based on a given set point per action on the variables that describe the process. To achieve the desired results, the brushless DC machine model will be studied. With the model obtained, both types of regulator will be tested. A synthesis of the observed comparison results will enable a conclusion to be drawn on the performance of the two types of regulators driving a BLDC (Brushless DC).

Exponential Dichotomy and Eberlein-Weak Almost Periodic Solutions

We give sufficient conditions ensuring the existence and uniqueness of an Eberlein-weakly almost periodic solution to the following linear equation dx/dt(t) = A(t)x(t) + f(t) in a Banach space X, where (A(t)) t ∈□ is a family of infinitesimal generators such that for all t ∈□, A(t + T) = A(t) for some T > 0, for which the homogeneuous linear equation dx/dt(t) = A(t)x(t) is well posed, stable and has an exponential dichotomy, and f:□ →X is Eberlein-weakly amost periodic.

On the study of hydrodynamic instabilities in the presence of background magnetic fields in high-energy-density plasmas

Blast-wave-driven hydrodynamic instabilities are studied in the presence of a background B-field through experiments and simulations in the high-energy-density(HED)physics regime.In experiments conducted at the Laboratoire pour l’utilisation des lasers intenses(LULI),a laserdriven shock-tube platform was used to generate a hydrodynamically unstable interface with a prescribed sinusoidal surface perturbation,and short-pulse x-ray radiography was used to characterize the instability growth with and without a 10-T B-field.The LULI experiments were modeled in FLASH using resistive and ideal magnetohydrodynamics(MHD),and comparing the experiments and simulations suggests that the Spitzer model implemented in FLASH is necessary and sufficient for modeling these planar systems.These results suggest insufficient amplification of the seed B-field,due to resistive diffusion,to alter the hydrodynamic behavior.Although the ideal-MHD simulations did not represent the experiments accurately,they suggest that similar HED systems with dynamic plasma-β(=2μ_(0)ρv^(2)/B^(2))values of less than∼100 can reduce the growth of blast-wave-driven Rayleigh–Taylor instabilities.These findings validate the resistive-MHD FLASH modeling that is being used to design future experiments for studying B-field effects in HED plasmas.

Scattering of ultrashort laser pulses on plasmons in a Maxwellian plasma

On the basis of equations obtained in the framework of second-order quantum-mechanical perturbation theory,the standard approach to the calculation of scattering radiation probability is extended to the case of ultrashort laser pulses.Weinvestigate the mechanism of the appearance of plasmon peaks in the spectrum of the plasma form factor for different parameters of the problem.For the case in which scattering on plasmons dominates over scattering on electron density fluctuations caused by chaotic thermal motion,we derive analytical expressions describing the scattering probability of ultrashort laser pulses on plasmons.Together with this,we obtain a simple expression connecting the frequency of scattered radiation and the energy transmitted from the incident pulse to plasmon,and vice versa.In considering the scattering probability,our emphasis is on the dependence on the pulse duration.Weassess in detail the trends of this dependence for various relations between pulse carrier frequency and plasmon energy.

A New Paradigm for the Extraction of Information: Application to Enhancement of Visual Information in a Medical Application

The noninvasive evaluation of the cardiac function presents a great interest for the diagnosis of cardiovascular diseases. Tagged cardiac MRI allows the measurement of anatomical and functional myocardial parameters. This protocol generates a dark grid which is deformed with the myocardium displacement on both Short-Axis (SA) and Long-Axis (LA) frames in a time sequence. Visual evaluation of the grid deformation allows the estimation of the displacement inside the myocardium. The work described in this paper aims to make robust and reliable the visual enhancement of the grid tags on cardiac MRI sequences, thanks to an informational formalism based on Extreme Physical Informational (EPI). This approach leads to the development of an original diffusion pre-processing allowing us to make better the robustness of the visual detection and the following of the grid of tags.

The effect of doped ions on single-molecule magnets of the Mn_(12)-Ac family

This paper investigates the single-molecule magnets of pure and Cr/Fe-doped Mn12-Ac. The components of the mixed crystals are identified by AC susceptibility technique. The ground-state spin and anisotropy parameters of doped Mn12-Ac are obtained： （i） MnllCr-Ac （S=19/2, D=0.62K, B=0.0009K, A=63K）, and （ii） Mn11Fe-Ac （S=21/2, D=0.39 K, B=0.001 K, △=55 K）. The single-ion origin of the magnetic anisotropy is discussed.

Removing harvest residues from hardwood stands affects tree growth, wood density and stem wood nutrient concentration in European beech (Fagus sylvatica) and oak (Quercus spp.)

Background:Higher exportation of harvest residues from forests due to increased demand for woody biomass,has reportedly diminished soil mineral resources and may lead to degraded tree nutrition as well as growth.However,as nutrients become less available in the soil,the remobilization of nutrients in biomass tissues(plant internal cycling)helps sustain tree nutrition.Our study aims to quantify the impact of Removing Harvest Residues and Litter(RHRL)during five years on tree growth,wood density,and stem wood nutrient concentrations in young beech and oak forest stands.Result:Our study found that,RHRL significantly decreased tree growth ring width by 14%,and wood density by 3%,in beech trees,in near bark rings.RHRL also significantly reduced nutrient concentration in near bark and near pith areas of both studied species.Mg,Na and S were found lower by 44%,76%,and 56%,respectively,in near bark area of beech trees.In near bark area of oak trees,K,Ca,Mg,Na,S,and Fe were lower by 20%,25%,41%,48%,41%,and 16%,respectively.K and Mg concentrations decreased more strongly in near pith area compared to near bark area suggesting internal translocation of these two elements.Conclusion:In beech trees,wood density proved to be an important factor while quantifying the effect of removing harvest residuals on tree growth and biomass.Soil nutrient loss intensified the remobilization of nutrients con-tained in older tree rings(close to the pith)towards newly formed rings(close to bark).In our study,in beech trees,K was found to be the most recycled major nutrient.These results demonstrate the potential of such analysis for providing valuable insight into the effect of RHRL in premature stands on the physiological adaptive strategies of trees and an indication of soil fertility status.

Phase Diagrams of the Semi-Infinite Blume-Capel Model with Mixed Spins (SA = 1 and SB = 3/2) by Migdal Kadanoff Renormalization Group

We study the mixed spin-1 and spin-3/2 Blume-Capel model under crystal field in the tridimensional semi-infinite case. This has been done by using the real-space renormalization group approximation and specifically the Migdal-Kadanoff technique. As a function of the ratio R of bulk and surface interactions and the ratios R1 and R2 of bulk and surface crystals fields on the spin-1 and spin-3/2 respectively, we have determined various types of phase diagrams. Besides second- order transition lines, first-order phase transition lines terminating at tricritical points are obtained. We found that there existed nine main types of phase diagram showing a variety of phase transitions associated with the surface, including ordinary, extraordinary, surface and special phase transitions.

Modeling of the Global Daily Horizontal Solar Radiation Data over Togo

Solar photovoltaic appears to be the most interesting renewable energy in developing countries where its deposit is abundant. Unfortunately, the lack of precise knowledge of solar radiation deposit and its limited data hinder optimal exploitation of solar installations. This study presents a performing model for daily global horizontal solar radiation for the five regional capitals in Togo: Lomé, Atakpamé, Sokodé, Kara and Dapaong. The data used for the study were obtained from the General Directorate of National Meteorology of Togo, for five years. The model developed combines linear and nonlinear methods with harmonic and exponential terms taking into account climatological parameters such as location latitude, daily relative humidity, daily ratio of sunshine duration and daily mean temperature. Statistical errors of the model were compared to those of two previous models elaborated for Togo and Nigeria. The results showed that the model is more efficient to predict global horizontal solar radiation over the five main cities in Togo. The comparison of estimated data and measured ones showed a good agreement between them.

Crystal Structure, Thermal Behaviour and Vibrational Spectra of Tetraethylammonium Dihydrogenmonophosphate Bis Phosphoric Acid

Single crystals of the tetraethylammonium dihydrogenmonophosphate bis trihydrogenmonophosphate [CH3CH2]4N+(H2PO4)(H3PO4)2(TEP), were grown by slow evaporation solution technique at room temperature. The compound was characterised by IR, Raman, differential thermal analysis (TG-DTA) and single crystal X-ray diffraction. It crystallizes in the monoclinic system (space group P21/c) with the following unit cell dimensions: a = 7.765 (2) , b = 16.531 (4) , c = 14.843 (2) , β = 100.99 (2)o, Z=4 , DX =1.67Mg.m-3, Dm=1.532Mg-3, λ (MoKa) = 0.71073 , u=0.384 mm-1, F(000)=991, T = 20 (2)o. The structure was solved by the direct method and refined to final R value of 0.0342 and Rw=0.107 for 3239 independent [(CH3CH2)4N]+ reflections. The structure consists of infinite parallel two-dimensional planes built of mutually , H3PO4 tetrahedra ?and cations connected by strong and hydrogen bonding. There are no contacts other than van der Waals interactions between the layers.

Numerical Study of Mixed Convection in a Photovoltaic Trombe Wall Channel Coupled with a Solar Chimney Integrated into a Building for Habitats Passive Cooling

The solar chimney can generate airflow through the living space of the building to provide cooling. Hence, solar energy represents the best renewable, environmentally friendly source of energy that can be used for heating and cooling of houses. The present paper reports the numerical study of the performance of the mixed convection in the associated hybrid Photovoltaic/Thermal chimneys integrated into building for natural habitat ventilation. The front side glass plate of the chimneys is heated by a non-uniform daily solar radiation flux. Air is considered to be the cooling fluid. The stream fucntion-vorticity formulation with a finite difference numerical discretization solution scheme has been adopted. The system of algebraic governing equations is solved by Thomas algorithm method. The aim of the present paper is to study and to predict the dynamic fields and particularly of the mass flow rate of the air thermosiphon drawing in the associated hybrid Photovoltaic-Thermal chimneys integrated into a building for passive cooling in the habitats. The effects of the governing parameters, namely Reynolds number (30 ≤ Re ≤ 200), Rayleigh number (103 ≤ Ra≤ 105), the integrated chimney width on the fluid flow and the heat transfer characteristics, are studied in detail. The local Nusselt number, streamlines, isotherms, PV cells electrical efficiency and the outlet velocity at the top of the channels are the results represented versus the above controlling parameters.

Crystal Structure and Physicochemical Properties of 2-Diisopropylammonium Ethylammonium Sulfate Dihydrate

A new organic sulfate (C8H22N2)SO42H2O denoted DPAES is obtained by interaction of H2SO4 with the organic molecule 2-[Diisopropylamino] ethylamine. We describe its crystallographic and structural features. DPAES is triclinic, Pī, with the lattice parameters a = 6.8841(2)?, b = 8.4966(2)?, c = 12.0804(3)?, = 81.824(1)o, = 88.007(1)o, = 78.649(1)o, V = 685.72(3)?3, and Z = 2. Its atomic arrangement is described as inorganic chains of SO42- units and water molecules, these chains are interconnected by organic groups so as to build layers parallel to the (001) planes. The IR data of DPAES are reported and discussed according to the theoretical group analysis and by comparison with IR results of similar compounds. The coupled TG-DTA thermal study shows the departure of two water molecule, con- firming the hydrated character of this compound.

XFEL and HHG interaction with matter:Effects of ultrashort pulses and random spikes

The theory of photoionization describing the interaction of x-ray free-electron laser(XFEL)pulses and high-harmonic-generated(HHG)radiation is generalized to ultrashort laser pulses,where the concept of the standard ionization probability per unit time in Fermi’s golden rule and in Einstein’s theory breaks down.Numerical calculations carried out in terms of a generalized photoionization probability for the total duration of pulses in the near-threshold regime demonstrate essentially nonlinear behavior,while absolute values may change by orders of magnitude for typical XFEL and HHG pulses.XFEL self-amplified spontaneous emission pulses are analyzed to reveal general features of photoionization for random and regular spikes:the dependences of the nonlinear photoionization probability on carrier frequency and spike duration are very similar,allowing an analytical expectation value approach that is valid even when there is only limited knowledge of random and regular parameters.Numerical simulations carried out for typical parameters demonstrate excellent agreement.

Energy Efficiency of Briquettes Derived from Three Agricultural Waste’s Charcoal Using Two Organic Binders

Waste management could contribute significantly to reducing environmental degradation. Studies showed that briquetting provides with or without binder helps to manage wastes as energy fuels. However, the properties of many binders are not investigated extensively. This work investigated the effect of two organic binders’ low rate on energy efficiency of Briquettes produced from charcoals of Tender Coconut Husks (TCH), Palm Kernel Shells (PKS) and Corn Cobs (CC). Bombax Costatum calyx (B) and Cissus Repens barks (C) were used separately as binders to elaborate briquettes. The briquettes were compared based on their energy efficiency parameters with wood charcoal as control. Energy efficiency parameters such as water boiling time (WBT), mass of biomass used (MB), burning rate (BR), temperature rise rate (TR) and maximum temperature in the furnace (Tmax) were measured from each biomass charcoal briquette and wood charcoal combustion. Water boiling test was applied to determine briquettes thermal properties. The results of WBT, BR, TR and Tmax were respectively within the ranges 3.4 - 12.3 min, 2.90 - 7.71 g/min, 4.63°C/s - 16.10°C/s and 623°C - 900°C. Corn Cobs charcoal briquettes with Bombax binder took the shortest time to boil water and also presented a high temperature rise rate and the highest maximum temperature. The lowest burning rates were obtained for Tender coconut husks charcoal briquettes with Cissus binder. They showed good material conservation for bombax bound briquettes. The results of our investigations showed that binders content increasing enhanced the thermomechanical stability and affected negatively the energy efficiency parameters of the studied briquettes.