Analysis of CO_2 utilization into synthesis gas based on solar thermochemical CH_4-reforming

In this study, the solar thermochemical reactor performance for CO_2 utilization into synthesis gas(H_2+ CO) based on CH_4 reforming process was investigated in the context of carbon capture and utilization(CCU) technologies. The P1 radiation heat transfer model is adopted to establish the heat and mass transfer model coupled with thermochemical reaction kinetics. The reactor thermal behavior with direct heat transfer between gaseous reactant and products evolution and the effects of different structural parameters were evaluated. It was found that the reactor has the potential to utilize by ～60% of CO_2 captured with 40% of CH_4 co-fed into syngas(72.9% of H_2 and 27.1% of CO) at 741.31 k W/mof incident radiation heat flux. However, the solar irradiance heat flux and temperature distribution were found to significantly affect the reactant species conversion efficiency and syngas production. The chemical reaction is mainly driven by the thermal energy and higher species conversion into syngas was observed when the temperature distribution at the inner cavity of the reactor was more uniform. Designed a solar thermochemical reactor able to volumetric store concentrated irradiance could highly improve CCU technologies for producing energy-rich chemicals. Besides, the mixture gas inlet velocity, operating pressure and CO_2/CH_4 feeding ratio were crucial to determining the efficiency of CO_2 utilization to solar fuels. Catalytic CO_2-reforming of CH_4 to chemical energy is a promising strategy for an efficient utilization of CO_2 as a renewable carbon source.

Place of Ultrasonographic in Screening Brain Lesions in Premature Newborn at Cotonou

Goal: The goal of this study is to define the epidemiological profile and identify the different brain lesions diagnosed in ultrasonography in preterm infants in Benin environment. Patients and methods: It is a prospective cross-sectional study of analytical aiming. It took place over a period of 6 months, from May 1st to October 31st, 2012 at the National Hospital University Centre Koutoukou Hubert Maga in neonatal units and medical scanning unit. It covered 105 premature newborn, classified into the very prematurity and the moderate prematurity. Results: The very premature represented 35.2% and the moderate premature 64.8%, with an average of 33.5% and 1.9 of standard deviation. The average age when implementing ultrasonographic transfontanellar was 7.2 ± 4.6 days old. The lowest birth weight was observed in very premature with p = 0.0025. The nasopharyngeal septum pellucidum was the most found lesions in 46 preterm infants (43.8%) with no statistically significantly difference in two groups, followed by the ventricular haemorrhage found in 21 preterm infants accounting for 20%, and the grade 1 or sub-ependymal haemorrhage prevailed in 14 premature accounting for 66.7%, afterward periventricular leukomalacia in 4 premature infants and hydrocephalus in 2 premature. Conclusion: The nasopharyngeal septum pellucidum and the sub-ependymal ventricular haemorrhage were the predominant anomalies in premature infants followed by leukomalacia.

A Modeling Study for Moisture Diffusivities and Moisture Transfer Coefficients in Drying of “Violet de Galmi” Onion Drying

In the present work, the mass transfer characteristics, namely moisture diffusivity and moisture transfer coefficient of “Violet de Galmi” variety of onions were evaluated using the analytical model. Onions were dried in a single layer at different temperatures (40℃, 50℃, 60℃, and 70℃) and for a relative humidity of drying air of 20%. The results showed a reasonably good agreement between the values predicted by the correlation and the experimental observations. This model computed the Biot number, effective moisture diffusivity, and mass transfer coefficient. Effective diffusion coefficient values are obtained between 0.2578 × 10-9 m2·s-1 and 0.5460 × 10-9 m2·s-1. Mass transfer coefficients of “Violet de Galmi” onion drying vary between 3.37 × 10-7 m·s-1 and 13.38 × 10-7 m·s-1. Numbers of mass transfer Biot are found between 0.9797 and 2.9397. The activation energy Ea is 31.73 kJ·mol-1.

Radiative heat transfer and thermal characteristics of Fe-based oxides coated SiC and Alumina RPC structures as integrated solar thermochemical reactor

This paper investigated radiative heat transfer and thermal characteristics of Fe-based oxides coated SiC and Alumina reticulated porous ceramic structures as integrated solar thermochemical reactor.High-flux solar radiation absorption and axial temperature distribution in the ceramic foams reactor were analyzed by adopting surface-to-surface radiation model coupled to the P1approximation for radiation heat transfer.The radiative heat transfer and thermal characteristics of different foam-type RPC structures,including SiC,CeO_2,FeAl_2O_4,NiFeAlO_4,Fe_3O_4/SiC,and NiFe_2O_4/SiC were evaluated.The mass flow rate and foam structural parameters,including the permeability,pore mean cell size,and extinction coefficients have significantly affected the axial temperature distribution,pressure drop,heat transfer,and fluid flow.Integrated porous structure to the solar receiver could maximize the incorporation of redox powder in the reacting medium,lower the pressure drop,and enhance the thermal performance of the thermochemical reacting system.SiC structure was the candidate materials in the case where more heat flux and high axial temperature distribution is needed.However,Fe-based oxide coated Al_2O_3structure could be considered regarding the heat transfer enhancement along with the catalyst activity of oxygen carriers for solar thermochemical reacting system performance.