2,748 research outputs found
The impact of step feeding on rotating biological contactor performance - by Pascal Elias Saikaly
No full textThesis (M.S.)--American University of Beirut. Interfaculty Graduate Environmental Sciences Program (Environmental Technology), 2001;"Advisor: Dr. George Ayoub, Professor, Civil and Environmental Engineering--Member of Committee: Dr. Mutasem El- Fidel, AssBibliography : leaves 150-160Aerobic biological processes have been viewed as effective methods for the treatment of wastewater to remove biodegradable organics and, to a lesser extent, nutrients. The fixed-film process has some advantages over suspended growth processes such as sta
Samuel Beckett and the Writers of Port-Royal
No full textIt has been observed that ‘the literary influences on Beckett have been far more important than has been acknowledged, and more important indeed, than the philosophical influences’ (Smith 2002: 3). The truth of this statement is evidenced by the description that scholars have given of Samuel Beckett’s relationship to seventeenth century French classicism. To date, critical interest has been limited for the most part to the figure of the philosopher René Descartes on the (fragile) grounds that Beckett was exclusively concerned with the Cartesian imperative of clarity and order, the fundamental dualism between body and mind, and Nominalism.
Together with the assumption that Beckett’s vision was essentially Cartesian, his literary filiation with Pascal was suggested by critics, but only in terms of Beckett’s formal approach to the theatre. In his short article on En attendant Godot in 1953, the playwright Jean Anouilh was among the first reviewers to suggest that Beckett’s drama synthesizes the encounter between ‘classicism’ and a ‘modern’ form of art. It is well known that Beckett retained a lifelong admiration for Pascal – indeed, Pascal was one of his ‘old chestnuts’ (Knowlson 1997: 653). Little attention has been paid, however, to the originality of Pascal’s thought, the specific nature of his prose, and the impact these might have had upon Beckett’s mature work, especially the trilogy and the subsequent short prose. Yet, in the literary and philosophical context of post-war France, Beckett’s filiation with Pascal, their corresponding preoccupations, were evident to his contemporaries, who identified Pascal as an underlying presence in his works
Effects of set cathode potentials on microbial electrosynthesis system performance and biocathode methanogen function at a metatranscriptional level.
No full textMicrobial electrosynthesis exploits the catalytic activity of microorganisms to utilize a cathode as an electron donor for reducing waste CO2 to valuable fuels and chemicals. Electromethanogenesis is the process of CO2 reduction to CH4 catalyzed by methanogens using the cathode directly as a source of electrons or indirectly via H2. Understanding the effects of different set cathode potentials on the functional dynamics of electromethanogenic communities is crucial for the rational design of cathode materials. Replicate enriched electromethanogenic communities were subjected to different potentials (- 1.0 V and - 0.7 V vs. Ag/AgCl) and the potential-induced changes were analyzed using a metagenomic and metatranscriptomic approach. The most abundant and transcriptionally active organism on the biocathodes was a novel species of Methanobacterium sp. strain 34x. The cathode potential-induced changes limited electron donor availability and negatively affected the overall performance of the reactors in terms of CH4 production. Although high expression of key genes within the methane and carbon metabolism pathways was evident, there was no significant difference in transcriptional response to the different set potentials. The acetyl-CoA decarbonylase/synthase (ACDS) complex were the most highly expressed genes, highlighting the significance of carbon assimilation under limited electron donor conditions and its link to the methanogenesis pathway.This work was supported by the Competitive Research Grant (URF/1/2985-01-01) awarded to Pascal E. Saikaly from King Abdullah University of Science and Technology (KAUST)
The combined effect of step-feed and recycling on RBC performance
No full textThe effect of step-feed and recycling on the efficiency of treatment in rotating biological contractors (RBCs) was investigated. Experiments were conducted on a RBC system consisting of two three-stage units. The two units were operated in parallel, one unit as a control with a single feed point and the other in a step-feed mode. Seven experimental runs were conducted, using a simple synthetic wastewater, in which hydraulic loading rates were maintained constant at about 0.094m3-m2d and variable COD concentrations (800-1200mg-L), NH3-N concentrations (104-116mg-L), step-feed ratios (60-40 and 70-30), and recirculation modes. Results indicate that improvements in the treatment efficiencies of RBC systems may be attained by operating the system in a step feed mode as compared to a single point feed mode. Further improvements may also be obtained by inducing effluent recirculation to the inlet stage. In both cases, levels of improvement have shown to be more pronounced for NH3-N removals and DO residual concentrations as compared to COD removals. The combined effect of step feed and recirculation of system effluent on NH3-N removal efficiencies is appreciable. Comparing removal efficiencies between the control, step feed and the combined step-feed-recirculation modes shows an increase of about 26percent. For COD removals, the effect is not that pronounced as the results for the combined modes of operation indicate a limited increase in overall removal efficiency of about 3percent. Supplementing step feed by a recircutation system also markedly improved DO residuals in stages 1 and 2 and to a lower extent in stage 3 of the system. Changing the ratio in the step feed system from 60-40percent to 70-30percent exhibited a slight improvement in NH3-N removal efficiencies as well as improved residual DO concentrations but very limited effect on COD removals. The use of a simple synthetic wastewater in the experiments may limit extrapolation of the findings to actual operation. © 2004 Elsevier Ltd. All rights reserved.[APHA-AWWA-WEF A. P. H. A. A. W. W. A. W. E. Federation], 1995, STAND METH EX WAT WA; GUARINO CF, 1977, 50 ANN WPCF C PHIL P, P1; ITO K, 1980, P 1 NAT S RBC TECHN, P1165; JANCZUKOWICZ W, 1992, BIORESOURCE TECHNOL, V42, P241, DOI 10.1016-0960-8524(92)90027-U; KHARAJIAN H, 1984, P 2 INT C FIX FILM B, V1, P709; KLEES R, 1992, WATER SCI TECHNOL, V26, P545; Metcalf and Eddy Inc., 1991, WAST ENG TREATM DISP; NEU KE, 1994, WATER SCI TECHNOL, V29, P197; RUSTEN B, 1984, 2 INT C FIX FILM BIO, V1, P754; Saikaly P., 2001, THESIS AM U BEIRUT B; Surampalli RY, 1997, WATER AIR SOIL POLL, V98, P1; WATNABE Y, 1995, WATER SCI TECH, V31, P19520161
Pre-enriched electrodes, bioelectrochemical processes, and biomass retention collectively enhance methane production in integrated microbial electrolysis cell-anaerobic digestion system
No full textThis study systematically examined the effect of different microbial electrolysis cell (MEC) components (i.e., anode, cathode, and suspension) on CH4 production in MEC-anaerobic digestion (MEC-AD) system. The impact of pre-enriching the anode with Geobacter sulfurreducens and the cathode with hydrogenotrophic methanogens was evaluated. CH4 production was 14 ± 4 % higher in reactors with pre-enriched electrodes (PEE) than virgin electrodes (VE) under both open and closed-circuit conditions, demonstrating the advantages of electrode pre-enrichment. Closed circuit reactors (PEE-CC & VE-CC) exceeded open circuit reactors (PEE-OC & VE-OC) in CH4 production by 16.5 ± 2 %, underscoring the importance of bioelectrochemical processes. VE-OC reactors produced 12 ± 2 % more CH4 than AD without electrodes (AD-NE), which recorded the lowest CH4 production (306 ± 5 ml), highlighting the role of biomass retention. The suspension contributed most significantly to CH4 production in all MEC-AD reactors (43–62 %), followed by the cathode (21–32 %) and the anode (7–19 %). G. sulfurreducens and D. acetexigens dominated the anodes of PEE-CC and VE-CC reactors, respectively, while Methanobacterium was prevalent on the cathode. The detection of 19 diverse methanogen species underscores the metabolic diversity of the system. These results highlight the synergistic effects of electrode pre-enrichment, bioelectrochemical processes, and biomass retention in enhancing AD performance by improving system stability and robustness.This work was supported by Center Competitive Funding Program (FCC/1/1971-33-01) awarded to Pascal E. Saikaly from King Abdullah University of Science and Technology (KAUST)
Sabil and Wikala of Dhul Fiqar Oda Bashi
No full textinterior, courtyard, "Vue de l'Okel Zoulfiqar," color plate XLIV of Pascal Coste's "Architecture arabe; ou, Monuments du Kaire, mesurés et dessinés, de 1818 à 1826", 1818-182
First person - Aude Pascal
No full textInternational audienceFirst Person is a series of interviews with the first authors of a selection of papers published in Journal of Cell Science, helping early-career researchers promote themselves alongside their papers. Aude Pascal is first author on `Annexin A2 and Ahnak control cortical NuMA-dynein localization and mitotic spindle orientation', published in JCS. Aude is a research assistant in the lab of Re ' gis Giet at University of Rennes, France, who is particularly interested in developmental biology. She has always been struck by the fact that a whole organism displaying multiple functions arises from a single cell. For this reason, she has oriented her research on mitosis and meiosis to study the different steps, components and structures involved in these processes
Pascal Tutorial, 1987
No full textThere exists a limited number of tutorials for the Pascal programming language using the Apple Computer. The demand for these tutorials exceeds the supply. In this thesis an attempt was made to rectify this shortage by designing a Pascal tutorial for the Apple computer. This Pascal tutorial is designed to assist with instructing an introductory computer programming course in Pascal, incorporating Apple Superpilot as the authoring language. Emphasis is placed on making the program "user friendly." A person with no previous programming experience should be able to easily execute this tutorial. The information presented as the subject matter of the tutorial will follow the guidelines recommended by the Association for Computing Machinery
Architecture arabe; ou, Monuments du Kaire, mesurés et dessinés, de 1818 à 1826
No full textgeneral view, "Vue des Tombeaux au Nord-Est de la Ville," color plate LXIII of Pascal Coste's "Architecture arabe; ou, Monuments du Kaire, mesurés et dessinés, de 1818 à 1826", 1818-182
Gamia el-Muaiyad
No full textinterior, qibla wall, "Vue de la Niche du Sanctuaire et de la Chaire de la Mosquee el Moyed"," color plate XXVIII of Pascal Coste's "Architecture arabe; ou, Monuments du Kaire, mesurés et dessinés, de 1818 à 1826", 1818-182
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