2,407 research outputs found
Garden compost inoculum leads to microbial bioanodes with potential-independent characteristics
No full textGarden compost leachate was used to form microbial bioanodes under polarization at 0.4, 0.2 and +0.1 V/SCE. Current densities were 6.3 and 8.9 A m2 on average at 0.4 and +0.1 V/SCE respectively, with acetate 10 mM. The catalytic cyclic voltammetry (CV) showed similar electrochemical characteristics for all bioanodes and indicated that the lower currents recorded at 0.4 V/SCE were due to the slower interfacial electron transfer rate at this potential, consistently with conventional electrochemical kinetics.RNA- and DNA-based DGGE evidenced that the three dominant bacterial groups Geobacter, Anaerophaga and Pelobacter were identical for all bioanodes and did not depend on the polarization potential. Only non-turnover CVs showed differences in the redox equipment of the biofilms, the highest potential promoting multiple electron transfer pathways. This first description of a potential-independent electroactive microbial community opens up promising prospects for the design of stable bioanodes for microbial fuel cells
Testing various food-industry wastes for electricity production in microbial fuel cell
No full textThree food-industrywastes: fermented apple juice (FAJ), wine lees and yogurt waste (YW) were evaluated in combination with two sources of inoculum, anaerobic sludge and garden compost, to produce electricity in microbialfuelcells. Preliminary potentiostatic studies suggested that YW was the best candidate, able to provide up to 250 mA/m2 at poised potential +0.3 V/SCE. Experiments conducted with two-chamber MFCs confirmed that wine lees were definitely not suitable. FAJ was not able to start an MFC by means of its endogenous microflora, while YW was. Both FAJ and YW were suitable fuels when anaerobic sludge or compost leachate was used as inoculum source. Sludge-MFCs had better performance using YW (54 mW/m2 at 232 mA/m2). In contrast, compost-leachate MFCs showed higher power density with FAJ (78 mW/m2 at 209 mA/m2) than with YW (37 mW/m2 at 144 mA/m2) but YW gave more stable production. Under optimized operating conditions, compost-leachate MFCs fueled with YW gave up to 92 mW/m2 at 404 mA/m2 and 44 mW/m2 in stable conditions
Mr Alain Elkann Author and Journalist Italian Republic
No full textVisit by Mr Alain Elkann Author and Journalist Italian Republi
Résister à la normalisation des conduites : Entretien avec Roland Gori, propos recueillis par Alain Policar
No full textCo-initiator of the call of calls denouncing the ideology of a neuroeconomic man in whose name the current reforms break and redial our jobs and tasks of care, social works, education, research, justice, information and culture, the author analyzes mainly the psychiatric knowledge and practice as facts of civilization.Co-initiateur de l'Appel des appels qui dénonce l'idéologie d'un «homme économique» au nom de laquelle les réformes actuelles défont et recomposent les métiers et les missions du soin, du travail social, de l'éducation, de la recherche, de la justice, de l'information et de la culture, l'auteur analyse ici principalement les savoirs et les pratiques psychiatriques comme «des faits de civilisation».Policar Alain, Gori Roland. Résister à la normalisation des conduites : Entretien avec Roland Gori, propos recueillis par Alain Policar. In: Raison présente, n°171, 3e trimestre 2009. Savoir, connaitre, agir. pp. 87-94
Forming microbial anodes under delayed polarisation modifies the electron transfer network and decreases the polarisation time required.
No full textMicrobial anodes were formed from compost leachate on carbon cloth electrodes. The biofilms formed at the surface of electrodes kept at open circuit contained microorganisms that switched their metabolism towards electrode respiration in response to a few minutes of polarisation. When polarisation at -0.2 V/SCE (+0.04 V/SHE) was applied to a pre-established biofilm formed at open circuit (delayed polarisation), the bacteria developed an extracellular electron transport network that showed multiple redox systems, reaching 9.4 A/m(2) after only 3-9 days of polarisation. In contrast, when polarisation was applied from the beginning, bacteria developed a well-tuned extracellular electron transfer network concomitantly with their growth, but 36 days of polarisation were required to get current of the same order (6-8 A/m(2)). The difference in performance was attributed to the thinner, more heterogeneous structure of the biofilms obtained by delayed polarisation compared to the thick uniform structure obtained by full polarisation
Alain de Lille
No full textAlain de Lille (c. 1128-1202) was a French monk and the author of the very popular and influential Ars Praedicandi (Art of Preaching).https://mds.marshall.edu/sermonstudies_gallery/1001/thumbnail.jp
Forming electrochemically active biofilms from garden compost under chronoamperometry
No full textDimensionally stable anodes (DSA) were polarized at different constant potential values for several days in garden compost. After an initial lag period ranging from 1 to 10.5 days, the current increased fast and then stabilized for days. Current densities higher than 100 mA m2 and up to 385 mA m2 were obtained with the sole organic matter contained in compost as substrate. Control experiments performed with sterilized compost, oscillations of the current with the temperature, kinetics of the exponential phase of current increase and observations of the surface of electrodes by epifluorescence microscopy showed that the current was controlled by the colonization of the electrode surface by a biofilm which originated the indigenous flora of compost. Three individually addressed electrodes polarized at different potentials in the same reactor led to identical current evolutions on each electrode, which underlined the key role of the microbial flora of the compost in the discrepancy observed in the other experiments. Chronoamperometry revealed a promising technique to check natural environments for new electrochemically active microbial species
From knowledge to skills: training for transition jobs. Interview with Alain Grandjean
No full textInternational audienceAlain Grandjean is an economist and author specializing on green finance. He is also cofounder and partner of Carbone 4, a consultancy firm focusing on energy transition and adaptation to climate change. The interview first revolves around the academic content Alain Grandjean considers as the bare necessities to be taught in higher education, no matter the curriculum. This should take the form of a basic synthetic training which takes into account the major environmental issues without too much technicality as well as lessons in accounting and economics, which he considers essential. The interview also looks more specifically at engineering and business schools. Then Alain Grandjean shares his views on the effectiveness of different ways to engage for the transition -like radical individual lifestyle transformations and civil disobiedience. He also evokes the roles that trade unions as well as NGOS can play and he talks about collapsology
Acetate to enhance electrochemical activity of biofilms from garden compost
No full textDimensionally Stable Anodes embedded in garden compost and maintained under constant polarization at 0.50 V/SCE for several days progressively became covered by a microbial biofilm that gave them the capability to oxidize the organic matter contained in the compost. The effect of acetate supply on the electrochemical activity of biofilms was investigated either by adding acetate after biofilm formation or mixing it into the compost initially. Addition of acetate allowed the current density values to increase up to 545 mA/m2. Six individually monitored electrodes set up in the same reactor showed very good reproducibility, indicating that discrepancies observed between the different experiments were mainly due the different batches of compost. A numerical treatment of the epifluorescent microscopy pictures allowed the biofilm coverage ratios to be assessed. Comparing the variations of current density during chronoamperometry with the biofilm surface coverage ratios and with the current obtained by cyclic voltammetry led us to propose a mechanism based on two different steps that corresponded to different time-scales: slow acetate oxidation through the cell metabolism and fast electron transfer between the cell and the electrode surface
Justice et politique (24) - face A
No full textSéminaire dirigé par Alain Bancaud, Anne Boigeol, Henry Rousso et Francine Soubiran-Paillet. Enregistré à l'IHTP (Paris), entre 1995 et1998
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