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Solar chemical looping reforming of methane combined with isothermal H2O/CO2 splitting using ceria oxygen carrier for syngas production

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Journal of Energy Chemistry 2020年第2期29卷 60-72页

作者： Srirat Chuayboon stéphane Abanades Sylvain Rodat Processes Materials and Solar Energy LaboratoryPROMES-CNRSFont-Romeu 66120France Department of Mechanical Engineering King Mongkut's Institute of Technology LadkrabangPrince of Chumphon CampusChumphon 86160Thailand Universite Grenoble Alpes Le-Bourget-du-Lac F-73375France CEA-LJTEN Laboratoire des Systemes Solaires Haute Temperature(LSHT) Grenoble F-38054France

The chemical looping reforming of methane through the nonstoichiometric ceria redox cycle(CeO2/CeO2-δ) has been experimentally investigated in a directly irradiated solar reactor to convert both solar energy and methane to syngas in the temperature range 900–1050 °C. Experiments were carried out with different ceria shapes via two-step redox cycling composed of endothermic partial reduction of ceria with methane and complete exothermic re-oxidation of reduced ceria with H2 O/CO2 at the same operating temperature, thereby demonstrating the capability to operate the cycle isothermally. A parametric study considering different ceria macrostructure variants(ceria packed powder, ceria packed powder mixed with inert Al2 O3 particles, and ceria reticulated porous foam) and operating parameters(methane flow-rate, reduction temperature, or sintering temperature) was conducted in order to unravel their impact on the bed-averaged oxygen non-stoichiometry(δ), syngas yield, methane conversion, and solar reactor performance. The ceria cycling stability was also experimentally investigated to demonstrate repeatable syngas production by alternating the flow between CH4 and H2 O(or CO2). A decrease in sintering temperature of the ceria foam was beneficial for increasing syngas selectivity, methane conversion,and reactor performance. Increasing both CH4 concentration and reduction temperature enhanced δ with the maximum value up to 0.41 but concomitantly favored CH4 cracking reaction. The ceria reticulated porous foam showed better performance in terms of effective heat transfer, due to volumetric absorption of concentrated solar radiation and uniform heating with lower solar power consumption, thereby promoting the solar-to-fuel energy conversion efficiency that reached up to 5.60%. The energy upgrade factor achieved during cycle was up to 1.19. stable patterns in the δ and syngas yield for consecutive cycles with the ceria foam validated material performance stability.

关键词： Chemical looping Methane reforming Ceria structure Concentrated solar power Syngas production H2O/CO2 splitting

Conversion of the refractory ammonia and acetic acid in catalytic wet air oxidation of animal byproducts

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Journal of Environmental Sciences 2011年第3期23卷 520-528页

作者： Virginie Fontanier Sofiane Zalouk stéphane Barbati Aix-Marseille Universite's-CNRS (UMR 6264)-Laboratoire de Chimie Provence:quipe Chimie de l'Environnement Continental-3 Place Victor Hugo (case 29)-13331 Marseille cedex 3France

Wet air oxidation （WAO） and catalytic wet air oxidation （CWAO） of slaughtered animal byproducts （ABPs） were investigated. Two step experiment was carried out consisting of a non-catalysed WAO run followed by a CWAO run at 170-275 ℃, 20 MPa, and reaction time 180 min. The WAO （lst step） of sample （5 g/L total organic carbon （TOC）） yielded （82.0 ±4）% TOC removal and （78.4 ± 13.2）% conversion of the initial organic-N into NH4＋-N. Four metal catalysts （Pd, Pt, Rh, Ru） supported over alumina have been tested in catalytic WAO （2nd step） at elevated pH to enhance ammonia conversion and organic matter removal, particularly acetic acid. It was found that the catalysts Ru, Pt, and Rh had significant effects on the TOC removal （95.1%, 99.5% and 96.7%, respectively） and on the abatement of ammonia （93.4%, 96.7% and 96.3%, respectively） with high nitrogen selectivity. The catalyst Pd was found to have the less activity while Pt had the best performance. The X-Ray diffraction analysis showed that the support of catalyst was not stable under the experimental conditions since it reacted with phosphate present in solution. Nitrite and nitrate ions were monitored during the oxidation reaction and it was concluded that CWAO of ammonia in real waste treatment framework was in good agreement with the results obtained from the literature for ideal solutions of ammonia.

关键词： wet oxidation, heterogeneous catalysis animal byproducts acetic acid ammonia, nitrite nitrate

Soil Physico-Chemical Properties and Different Altitudes Affect Arbuscular Mycorrhizal Fungi Abundance and Colonization in Cacao Plantations of Cameroon

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American Journal of Plant Sciences 2024年第2期15卷 57-82页

作者： Franklin Tounkam Ketchiemo Beaulys Fotso Astride stéphanie Mouafi Djabou Victor Jos Eyamo Evina Japhet Youri Essambita Franck Maxime Ewane Tang Nicolas Niemenak Laboratory of Plant Physiology and Biochemistry Department of Biological Sciences Higher Teacher Training College University of Yaounde I Yaounde Cameroon Department of Plant Biology Faculty of Sciences University of Yaounde I Yaounde Cameroon Faculty of Agronomy and Agricultural Sciences Bafia Annex University of Dschang Dschang Cameroon Applied Biotechnology Engineering Laboratory Department of Agriculture and Agropastoral Higher Teacher Training College University of Ebolowa Ebolowa Cameroon Plant Physiology Improvement Unit Laboratory of Biotechnology and Environment Department of Plant Biology Faculty of Sciences University of Yaounde I Yaounde Cameroon

This study aims to investigate the abundance of AMF according to soil properties and altitudes in different cacao plantations of Cameroon. Physico-chemical analyses were made on soil samples collected from three agro-ecological zones. Soil samples were also used to evaluate directly the AMF abundance following the various altitudes and after trapping by sorghum plant. The results showed that soil properties, AMF spore abundances and colonization fluctuated significantly at different altitudes. The most represented texture was sandy loam. The bimodal zone presented a homogeneous texture (sandy loam) in all its localities. Cacao soil chemical characteristics showed that, the highest nitrogen rate (0.47%;p 0.05, Scott-Knott test) was recorded at Melong in a monomodal zone while Tonga in the Western highlands displayed the lowest rate (0.13%). Soil P concentration was significantly high in monomodal zones (Mbanga and Melong). Soil pH level indicated that the soil from Tonga in the Western highlands was neutral (pH = 6.67), and soils of other localities under study were acidic with the lowest (4.75) pH level recorded at Melong in a monomodal zone. In soil samples, the highest spore density (1.03 spores/g soil) was observed at Ntui in Bimodal zone, while the lowest spore density (0.26 spores/g soil) was observed at Bafang in the Western highlands. Root colonization showed that the sample from Bokito in a bimodal zone displayed the best frequency of mycorrhization (86.11%) while the sample from Bafang in the Western highlands recorded the lowest (27.11%). The PCA analysis highlighted that available phosphorus, pH and altitude all strongly correlated with AMF root colonization ability and can be used as a predictor of AMF colonization ability in cacao rhizosphere.

关键词： Agroecological Zone Altitude Variations Arbuscular Mycorrhizal Fungi Soil Properties Theobroma cacao

Late-entry commercial thinning effects on Pinus banksiana:growth, yield, and stand dynamics in Québec, Canada

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Journal of Forestry Research 2019年第1期30卷 95-106页

作者： Martin-Michel Gauthier stéphane Tremblay Ministère des Forêts de la Faune et des Parcs du Québec Natural Resources Canada Canadian Forest Service

We studied late-entry commercial thinning effects on growth, yield, and regeneration in a 48-year-old jack pine(Pinus banksiana Lamb.) stand. Applied thinning intensities were 27, 32, and 47% of merchantable basal area(BA) excluding skidding trails. After 15 years, mean diameter at breast height of surviving trees in the 47% BA removal increased by 4.9 cm(25%) compared to the unthinned control. The 47% BA removal also increased gross merchantable volume(GMV) tree-1by 46% compared to the control. The 27% BA removal had twice as much GMV ha-1compared to the 47% BA removal after15 years. Moreover, cumulative GMV ha-1was much higher in the 27% BA removal than in the unthinned control. The highest thinning intensity produced larger trees on average, while the lowest thinning intensity maximized volume production per hectare. Maintenance of acceptable growing stock throughout the 15-year period in the 27% BA removal could provide other ecosystem functions such as biodiversity enhancement or wildlife habitat by delaying senescence. Regeneration data showed that a shift in species composition occurred in the understory. After 15 years, the understory was dominated by black spruce(Picea mariana(Mill.) B.S.P.), white birch(Betula papyrifera Marsh.), and trembling aspen(Populus tremuloides Michx.). If regenerating jack pine is an objective after final overstory removal, additional efforts will be needed to re-establish this species.

关键词： Jack pine Commercial thinning stand yield Succession Delayed senescence Tree regeneration

Magnesium sulfate and fetal neuroprotection: overview of clinical evidence

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Neural Regeneration Research 2018年第12期13卷 2044-2049页

作者： Clément Chollat stéphane Marret Institut National de la Santé et de la Recherche Médicale U1245 Genetics and Pathophysiology of Neurodevelopmental Disorders Team 4Neovasc Institute of Research and Innovation in Biomedicine Rouen School of Medicine Normandy University Department of Neonatal Intensive Care Port Royal University Hospital Department of Neonatal Pediatrics and Intensive Care and Neuropediatrics Charles-Nicolle University Hospital

Antenatal administration of magnesium sulfate is an important part of the neuroprotective strategy for preterm infants. strong evidence from five randomized controlled trials and five meta-analyses has demonstrated that magnesium sulfate, when administered before preterm delivery, significantly reduces the risk of cerebral palsy at two years. Through secondary analyses of randomized controlled trials and other original clinical studies, this state-of-the-art review highlights the absence of serious adverse effects in both pregnant women and neonates, as well as the impact of maternal body mass index and preeclamptic status on the maternal and neonatal magnesium levels, which could influence the magnitude of the neuroprotective effect. Although antenatal magnesium sulfate is a cost-effective strategy, some practice surveys have demonstrated that the use of magnesium sulfate is not sufficient and that its use is heterogeneous, differing among different maternity wards. Since 2010, an increasing number of obstetrical societies have recommended its use to improve the neurological outcomes of preterm infants, especially the International Federation of Gynecology and Obstetrics and World Health Organization in 2015, and France in 2017. Considering the neuroprotective impact of magnesium sulfate when administered before delivery, postnatal administration should be considered, and its effects should be assessed using randomized controlled trials.

关键词： magnesium sulfate preterm birth neuroprotection cerebral palsy neurodevelopment international recommendations clinical studies meta-analysis preeclampsia cost-effectiveness

New perspectives for investigating respiratory failure induced by cervical spinal cord injury

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Neural Regeneration Research 2014年第22期9卷 1949-1951页

作者： Marcel Bonay stéphane Vinit Université de Versailles Saint-Quentin-en-Yvelines Unité End:icapUFR des Sciences de la Santé–Simone Veil78180 Montigny-le-BretonneuxFrance Service de Physiologie-Explorations Fonctionnelles H?pital Ambroise Paré Assistance Publique-H?pitaux de Paris(AP-HP)Groupe Hospitalier Paris Ile-de-France Ouest92104 BoulogneBillancourtFrance

Traumatic cervical spinal cord injury （SCI）, with an annual incidence of 12,000 new cases in USA （NSCISC 2013）, causes devastating locomotor and respiratory paralysis and unfortunately compromises the human patient＇s lifespan. The severity of the injury depends on the degree and the extent of the initial trauma. In fact, respiratory failure is the leading cause of mortality following upper cervical SCI. However, 80% of the injuries are incomplete, allowing some modest spontaneous recovery. To date, no effective treatment is available in order to restore the loss of function.

关键词： SCI New perspectives for investigating respiratory failure induced by cervical spinal cord injury CPP

A PERTURBATION METHOD FOR THE NUMERICAL SOLUTION OF THE BERNOULLI PROBLEM

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Journal of Computational Mathematics 2008年第1期26卷 23-36页

作者： Franois Bouchon stéphane Clain Rachid Touzani Laboratoire de Mathématiques Universite Blaise Pascal (Clermont-Ferrand) and CNRS (UMR 6620) Campus Universitaire des Cézeaux63177 Aubière cedexFrance Laboratoire MIP UFR MIGUniversité Paul Sabatier Toulouse 3118 route de Narbonne31062 Toulouse cedex 4France Laboratoire de Mathematiques Université Blaise Pascal (Clermont-Ferrand) and CNRS (UMR 6620) Campus Universitaire des Cézeaux63177 Aubière cedexFrance

We consider the numerical solution of the free boundary Bernoulli problem by employing level set formulations. Using a perturbation technique, we derive a second order method that leads to a fast iteration solver. The iteration procedure is adapted in order to work in the case of topology changes. Various numerical experiments confirm the efficiency of the derived numerical method.

关键词： Bernoulli problem Free boundary Level sets

Benford or Not Benford:A Systematic But Not Always Well-Founded Use of an Elegant Law in Experimental Fields

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Communications in Mathematics and statistics 2020年第2期8卷 167-201页

作者： stéphane Blondeau Da Silva XLIM-Mathis UMR no 7252 CNRS-Universitéde Limoges123Avenue Albert Thomas87060 LimogesFrance

In this paper,we will propose a way to accurately model certain naturally occurring collections of *** this proposed model,the proportion of d as leading digit,d∈[1,9],in data is more likely to follow a law whose probability distribution is determined by a specific upper bound,rather than Benford’s Law,as one might have *** probability distributions fluctuate nevertheless around Benford’s *** peculiar fluctuations have often been observed in the literature in such data sets(where the physical,biological or economical quantities considered are upper bounded).Knowing beforehand the value of this upper bound enables to find,through the developed model,a better adjusted law than Benford’s one.

关键词： Benford’s Law Leading digit Experimental data

Considerations for the clinical use of stem cells in genitourinary regenerative medicine

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World Journal of stem Cells 2021年第10期13卷 1480-1512页

作者： Christophe Caneparo Luis Sorroza-Martinez stéphane Chabaud Julie Fradette stéphane Bolduc Centre de Recherche en Organogénèse Expérimentale de l'UniversitéLaval/LOEX Centre de Recherche du CHU de Québec-UniversitéLavalAxe Médecine RégénératriceQuebec G1J1Z4Canada Department of Surgery Faculty of MedicineUniversitéLavalQuebec G1V0A6Canada

The genitourinary tract can be affected by several pathologies which require repair or replacement to recover biological *** therapeutic strategies are challenged by a growing shortage of adequate ***,new options must be considered for the treatment of patients,with the use of stem cells(SCs)being *** different strategies can be derived from stem cell use:Cell therapy and tissue therapy,mainly through tissue *** recent advances using these approaches are described in this review,with a focus on stromal/mesenchymal cells found in adipose ***,the accessibility,high yield at harvest as well as anti-fibrotic,immunomodulatory and proangiogenic properties make adipose-derived stromal/SCs promising alternatives to the therapies currently offered to ***,an innovative technique allowing tissue reconstruction without exogenous material,the self-assembly approach,will be *** advances,more studies are needed to translate such approaches from the bench to clinics in *** the 21st century,cell and tissue therapies based on SCs are certainly the future of genitourinary regenerative medicine.

关键词： Genitourinary tract Cell therapy Tissue engineering stem cells