204 research outputs found
Synthesis, oxidation and unusual coordination chemistry of the diphosphete complex [(Cp′′′Co)2(μ,η4:4-(CH3CP)2)]
No full textNotwithstanding four decades of active research, very rare examples of diphosphabutadiene complexes arising from dimerisation of the phosphaalkyne CH3-C P have been reported. Herein, we show that methyl phosphaalkyne dimerises in the coordination sphere of Cp′′′Co fragments to yield the unprecedented diphosphete complex [Cp′′′Co(η4-P2C2Me2)] (1) and the triple-decker complex [{Cp′′′Co}2(μ,η4:η4-P2C2Me2)] (2). Compound 2 can be oxidised with Ag[Al{OC(CF3)3}4] (Ag[TEF]) to give [{Cp′′′Co}2(μ,η4:η4-P2C2Me2)][TEF] (3). Additionally, it shows an unusual coordination behaviour towards copper halides and [W(CO)4(nbd)] (nbd = norbornadiene). Its reaction with CuCl leads to the formation of the 1D polymer [{Cp′′′Co}2(μ,η4:η2:η1:η1-P2C2Me2){Cu(μ-Cl)}2]n (6) while its reaction with CuBr, CuI and [W(CO)4(nbd)] results in the metallacyclic compounds [(Cp′′′Co){μ3,η4:η1:η1-P2C2Me2}(CH3CN){Cu(μ-X)}2]2 (X = Br (7a), I (7b)) and [Cp′′′Co{μ3,η4:η1:η1-P2C2Me2}{W(CO)4}]3 (8). In 6, an isomerisation of the diphosphete ring to a diphosphacyclopentadienyl ring occurs. In 7 and 8, the loss of Cp′′′Co moieties from the former compound 2 is observed. The formation of 1,3-diphosphete rings in 1 and 2 instead of the more thermodynamically favoured 1,2-diphosphete rings are explained by DFT computations
Variation of selected air quality indicators over the city of Beirut, Lebanon: Assessment of emission sources
No full textIt is well established that the Mediterranean region experiences high pollution episodes as a result of its closed location and hot-humid long summers. However, few long-term field measurements have been conducted along the Eastern Mediterranean coast in general and in Arab countries, in particular. Hence, a six-month field study of major indicators like CO, SO2, PM10 and O3 were conducted in Beirut, Lebanon. Measurements on an upwind site showed that the monthly average concentrations of CO, SO2 and O3 were lower than the USEPA air quality standards while the monthly average concentrations of PM10 were higher. Diurnal variations showed that vehicle-induced emissions contribute significantly to CO levels while winter heaters constitute the major source of SO2. High diurnal and nocturnal levels of PM10 and O3 are the results of several local and long-range transport phenomena. © 2006 Elsevier Ltd. All rights reserved.Chaloulakou A, 2003, CHEMOSPHERE, V52, P1007, DOI 10.1016-S0045-6535(03)00263-7; Chaloulakou A, 2003, ATMOS ENVIRON, V37, P649, DOI 10.1016-S1352-2310(02)00898-1; Duenas C, 2002, SCI TOTAL ENVIRON, V299, P97, DOI 10.1016-S0048-9697(02)00251-6; Elbir T, 2000, ENVIRON INT, V26, P5, DOI 10.1016-S0160-4120(00)00071-4; El-Fadel M., 2002, ENV STUDIES A, V13, P471, DOI [10.1108-09566160210441780, DOI 10.1108-09566160210441780]; ELFADEL M, 2000, J TRANSPORTATION STA, V3, P85; El-Fadel M, 1999, TRANSPORT RES D-TR E, V4, P251, DOI 10.1016-S1361-9209(99)00008-5; El-Fadel M, 2000, SCI TOTAL ENVIRON, V257, P133, DOI 10.1016-S0048-9697(00)00503-9; El-Fadel M, 2001, ENERG POLICY, V29, P1031, DOI 10.1016-S0301-4215(01)00033-7; El-Hougeiri N, 2004, INDOOR BUILT ENVIRON, V13, P421, DOI 10.1177-1420326X04049344; Erduran AS, 2001, SCI TOTAL ENVIRON, V281, P205; Finlayson-Pitts B.J., 2000, CHEM UPPER LOWER ATM; Ganor E, 2000, ATMOS ENVIRON, V34, P3453, DOI 10.1016-S1352-2310(00)00077-7; Glavas S, 1999, ATMOS ENVIRON, V33, P3813, DOI 10.1016-S1352-2310(98)00393-8; Graham B, 2004, ATMOS ENVIRON, V38, P1593, DOI 10.1016-j.atmosenv.2003.12.015; Hashisho Z, 2004, ENVIRON MONIT ASSESS, V93, P185, DOI 10.1023-B:EMAS.0000016804.88534.34; He LY, 2004, ATMOS ENVIRON, V38, P6557, DOI 10.1016-j.atmosenv.2004.08.034; Kalabokas PD, 2000, ATMOS ENVIRON, V34, P5199, DOI 10.1016-S1352-2310(00)00298-3; Kourtidis KA, 2002, ATMOS ENVIRON, V36, P5355, DOI 10.1016-S1352-2310(02)00580-0; Kouvarakis G, 2000, J GEOPHYS RES-ATMOS, V105, P4399, DOI 10.1029-1999JD900984; Latha KM, 2004, ATMOS RES, V71, P265, DOI 10.1016-j.atmosres.2004.06.004; Lee SC, 2001, SCI TOTAL ENVIRON, V279, P181, DOI 10.1016-S0048-9697(01)00765-3; Lelieveld J, 2002, SCIENCE, V298, P794, DOI 10.1126-science.1075457; Liu YS, 2004, ENVIRON INT, V30, P189, DOI 10.1016-S0160-4120(03)00173-9; MOUSSA SG, 2005, IN PRES ATMOSPHERIC; Riga-Karandinos AN, 2005, CHEMOSPHERE, V59, P1125, DOI 10.1016-j.chemosphere.2004.11.059; Tov DA, 1997, ATMOS ENVIRON, V31, P1441; Tsitouridou R, 2003, CHEMOSPHERE, V52, P883, DOI 10.1016-S0045-6535(03)00313-8; Varinou M, 1999, PHYS CHEM EARTH PT C, V24, P507, DOI 10.1016-S1464-1917(99)00081-117202
Corrigendum to: Enhanced Long-term Stability and Carbon Resistance of Ni/MnxOy-Al2O3 Catalyst in Near-equilibrium CO2 Reforming of Methane for Syngas Production [15(2), 2020, 331-347]
No full textAccording to Authors request (10th December 2020), Corrigendum to: Djebarri, B., Touahra, F., Aider, N., Bali, F., Sehailia, M., Chebout, R., Bachari, K., Halliche, D. (2020). Bulletin of Chemical Reaction Engineering & Catalysis, 15(2), 2020, 331-347 (doi:10.9767/bcrec.15.2.6983.331-347). First Author (Baya Djebarri) is added as member of Corresponding Author because of his largest contribution in the article and his expertise.
Correction:
The Authors Names were corrected to:
Baya Djebarri1,*, Fouzia Touahra2,*, Nadia Aider4, Ferroudja Bali3, Moussa Sehailia2, Redouane Chebout2, Khaldoun Bachari2, Djamila Halliche3
The information detail of Corresponding Authors was corrected to:
* Corresponding Authors.
Email: [email protected] (F. Touahra); [email protected] (B. Djebarri)
Copyright © 2020 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0)
Rent - seeking trade policy : a time series approach
No full textUsing a time-series approach, the author analyzes the relationship between the extent of rent-seeking trade policy and both political and economic variables. For rent-seeking trade policy, the indicator he uses is the number of foreign-trade regulations passed each year for the benefit of a single firm or industry. The author uses data from Uruguay for 1925-83. Uruguay, which experienced an impressive economic decline, is an outstanding example of a rent-seeking society. After being a wealthy economy in midcentury, it suffered almost complete stagnation, which led to social and policital disintegration by the end of the 1960s. Three decades of restrictive regulations on foreign trade had created a nearly closed economy by the end of the 1960s. It was worth analyzing whether policymakers'great receptiveness to demands for protection could account for Uruguay's decline. Over the period 1925-83, the author finds almost 4,000 laws, decrees, and administrative resolutions that create, maintain, or modify a foreign-trade regulation for the benefit of a single firm or industry. About half of them explicitly identify the petitioner - usually a firm or guild. Since the size of the Uruguayan economy changed over the period studied, the author scales the annual number of regulations by output or exports to measure the extent of rent-seeking trade policy. The author shows that the extent of rent-seeking trade policy increased with discretionary policies and under dictatorship. (In the period studied, there were two stages of democracy - until 1932 and from 1943-72 - and two stages of dictatorship.) He also shows that rent-seeking trade restrictions increased under import-substitution strategies and, more unexpectedly, under active export promotion. This suggests that discretionary power leads to wasteful distribution, whether it is used to support inward- or outward-oriented policies. Finally, the author analyzes the correlation between innovations in the trade policy indicator and innovations in the growth rates of output and exports, with a lag of up to 20 years. Surprisingly, he finds a positive correlation with output growth rates after two or three years. But the correlation becomes negative some years later, particularly in the case of exports. The short-run positive impact on growth rates, together with the surprisingly long time lag before the negative impact, may account for policymakers'receptiveness to demands for protection.Trade Policy,Achieving Shared Growth,TF054105-DONOR FUNDED OPERATION ADMINISTRATION FEE INCOME AND EXPENSE ACCOUNT,Economic Theory&Research,Environmental Economics&Policies
An energy efficient Genetic Algorithm based approach for sensor-to-sink binding in multi-sink wireless sensor networks
No full textWireless sensor networks (WSNs) are ad-hoc networks in which sensors, that are designed to relay data back to sink nodes and-or Base Stations, are deployed in an area and may be configured in real time. Sensors, however, have limited energy supplies and are often left untouched after deployment, thus making battery replacement very difficult or even impossible. Therefore, energy should be efficiently conserved to extend the WSNs lifetime. One of the existing solutions is to deploy multiple sinks, more capable nodes in comparison to sensors, in the network to increase the coverage area and shorten the communication distance between sensors and sinks. However, this raises the issue concerning which sensors should bind to which sinks in order to avoid overloading particular sinks. In this paper, we devise a Genetic Algorithm based approach to solve the problem of balancing the load of sensors amongst sinks in a multi-sink WSN, while ensuring that the best routes to sinks are found for the sensors that cannot directly reach a sink. We evaluate the performance of our approach and compare it to an existing one using the network simulator NS-2 through measuring several metrics such as the variance of remaining energy among sinks, and energy consumption in sinks. The obtained results show that the proposed approach promising. © Springer Science+Business Media New York 2013.Akyildiz I. F., 2010, WIRELESS SENSOR NETW; Andel TR, 2006, COMPUTER, V39, P48, DOI 10.1109-MC.2006.242; English J, 2006, 2006 23rd Biennial Symposium on Communications, P320, DOI 10.1109-BSC.2006.1644632; Gupta G., 2003, P IEEE INT C COMM IC, V3, P1848; Hasancebi O, 2000, COMPUT STRUCT, V78, P435, DOI 10.1016-S0045-7949(00)00089-4; Kulik J, 2002, WIREL NETW, V8, P169, DOI 10.1023-A:1013715909417; Kim H, 2005, LECT NOTES COMPUT SC, V3391, P264; KIRKPATRICK S, 1983, SCIENCE, V220, P671, DOI 10.1126-science.220.4598.671; Min R., 2000, IEEE WORKSH SIGN PRO, P581; Perkins C. E., 1999, P 2 IEEE WORKSH MOB, V6, P90; Safa H., 2012, P IEEE INT IN PRESS; Safa H., 2011, 2011 Proceedings of IEEE Symposium on Wireless Technology and Applications (ISWTA 2011), DOI 10.1109-ISWTA.2011.6089389; Sinha A., 2000, P 13 INT C VLSI DES, P50; SRINIVAS M, 1994, COMPUTER, V27, P17, DOI 10.1109-2.294849; Tas N. C., 2008, P 17 IEEE INT C COMP, P1; Wang RL, 2004, NEUROCOMPUTING, V57, P463, DOI 10.1016-j.neucom.2003.12.003; Weng C.-E., 2012, COMMUNICATION, DOI [10.1007-s11277-012-0571-0, DOI 10.1007-S11277-012-0571-0]; Yi Poe W, 2008, P 14 GI ITG C MEAS M, P253; Zhu YH, 2011, MOBILE NETW APPL, V16, P58, DOI 10.1007-s11036-009-0211-41
Seasonal, diurnal and nocturnal behaviors of lower carbonyl compounds in the urban environment of Beirut, Lebanon
No full textLower carbonyl concentrations were measured for the first time in two different sampling sites (American University of Beirut (AUB) and Abdel-Aziz (AA)) in Beirut, Lebanon. Formaldehyde (C1) and acetaldehyde (C2) were the most abundant carbonyls with respective maximum concentrations of 12.2 and 5.2 ppbv at AUB and 8.6 and 5.1 ppbv at AA. Diurnal variations of carbonyls exhibited similar behaviors, suggesting related formation and decomposition routes. Morning levels of carbonyls were either equal or higher than the ones in the afternoon at the coastal site (AUB) due to atmospheric dilution. However, morning levels were mostly lower than noon levels at a three-busy street intersection (AA) due to the enhancement of photochemical activities. Vehicle emissions constituted the dominant source of carbonyls measured as confirmed by the good correlation between C1, C2 and propanal (C3) and the C1-CO and C2-CO ratios in the mornings. Seasonal variation showed the predominance of summertime photolysis and photo-oxidation reactions of aldehydes. Based on the measured formaldehyde levels, ozone and nitrous acid concentrations, morning and afternoon OH radical fluxes are computed and consequently their contribution to photochemical smog processes are assessed. © 2006 Elsevier Ltd. All rights reserved.ATKINSON R, 2003, SUMMARY EVALUATED KI, P1; Atkinson R, 2000, ATMOS ENVIRON, V34, P2063, DOI 10.1016-S1352-2310(99)00460-4; Atkinson R, 1997, J PHYS CHEM REF DATA, V26, P521; Baez AP, 2001, ATMOS ENVIRON, V35, P1813, DOI 10.1016-S1352-2310(00)00475-1; Bakeas EB, 2003, CHEMOSPHERE, V52, P805, DOI 10.1016-S0045-6535(03)00257-1; Cecinato A, 2002, J ENVIRON MONITOR, V4, P223, DOI 10.1039-b110616n; Christensen CS, 2000, ATMOS ENVIRON, V34, P287, DOI 10.1016-S1352-2310(99)00297-6; Correa SM, 2003, ATMOS ENVIRON, V37, P23, DOI 10.1016-S1352-2310(02)00805-1; Finlayson-Pitts B.J., 2000, CHEM UPPER LOWER ATM; Granby K, 1997, ATMOS ENVIRON, V31, P1403, DOI 10.1016-S1352-2310(96)00347-0; GROSJEAN D, 2002, RES REPORT HLTH EFFE, V107, P57; Grosjean E, 1996, ENVIRON SCI TECHNOL, V30, P2687, DOI 10.1021-es950758w; Ho KF, 2002, ATMOS ENVIRON, V36, P1259, DOI 10.1016-S1352-2310(01)00570-2; Kalabokas P, 1997, ATMOS ENVIRON, V31, P67, DOI 10.1016-S1352-2310(97)00075-7; Leong ST, 2002, ATMOS ENVIRON, V36, P3495, DOI 10.1016-S1352-2310(02)00288-1; Macdonald AM, 2001, J GEOPHYS RES-ATMOS, V106, P32361, DOI 10.1029-2001JD000513; Mohamed MF, 2002, CHEMOSPHERE, V47, P863, DOI 10.1016-S0045-6535(02)00107-8; Montero L, 2001, ENVIRON SCI TECHNOL, V35, P3071, DOI 10.1021-es001875g; Muller K, 1997, CHEMOSPHERE, V35, P2093, DOI 10.1016-S0045-6535(97)00267-1; Nguyen HTH, 2001, ATMOS ENVIRON, V35, P3075, DOI 10.1016-S1352-2310(01)00136-4; Possanzini M, 2003, ATMOS ENVIRON, V37, P1309, DOI 10.1016-S1352-2310(02)01010-5; Possanzini M, 1996, ATMOS ENVIRON, V30, P3757, DOI 10.1016-1352-2310(96)00110-0; Possanzini M, 2002, ATMOS ENVIRON, V36, P3195, DOI 10.1016-S1352-2310(02)00192-9; Seinfeld J.H., 1998, ATMOPSHERIC CHEM PHY; SIN D, 2001, ATMOS ENVIRON, V32, P5961; Slemr J, 1996, ATMOS ENVIRON, V30, P3667, DOI 10.1016-1352-2310(96)00025-8; Solberg S, 2001, ATMOS ENVIRON, V35, P195, DOI 10.1016-S1352-2310(00)00256-9; Viskari EL, 2000, ATMOS ENVIRON, V34, P917, DOI 10.1016-S1352-2310(99)00307-6; Wagner V, 2001, J GEOPHYS RES-ATMOS, V106, P28529, DOI 10.1029-2000JD900825; WINER AM, 1994, RES CHEM INTERMEDIAT, V20, P423, DOI 10.1163-156856794X00405; ZHOU X, 1997, MAR CHEM, V59, P201; ZHOU XL, 1990, ENVIRON SCI TECHNOL, V24, P1864, DOI 10.1021-es00082a013; Zou SC, 2003, CHEMOSPHERE, V51, P1015, DOI 10.1016-S0045-6535(03)00004-341463
Reactivity of aluminum sulfate and silica in molten alkalimetal sulfates in order to prepare mullite
No full textWith the aim of preparing mullite, reactions between aluminum sulfate and silica in appropriate proportions and molten sulfate media M2SO4 (M=Na and/or K) were performed at different temperatures. The powders obtained were characterized by XRD, FT-IR, SEM and TEM. The reactivity was the same in Na2SO4 and (K,Na)2SO4 media. The best results in terms of yield (98.3%) and weight of mullite produced (95%) were obtained in Na2SO4 at 950 °C. The mullite phase exhibits an acicular morphology (75×0.75 μm) and a specific surface area close to 20 m2/g. In K2SO4 medium, a potassium alumino silicate is formed as well as mullite
Costs and benefits of debt and debt service reduction
No full textThe author evaluates the costs and benefits of debt and debt service reduction (DDSR) from the point of view of five countries that have concluded Brady deals: Costa Rica, Mexico, the Philippines, Uruguay, and Venezuela. He concludes that, contrary to widely held views, commercial banks have probably benefited from the operations. Commercial bank participation in DDSR is voluntary, so direct financial savings to the country are probably negative at present values. The benefit from DDSR is not that debt is bought at"bargain prices"at the expense of commercial banks. It appears difficult to justify a DDSR operation on purely financial grounds. A more realistic way to look at a DDSR operation is to view it as a"project"that involves a certain financial cost. The return on such a project is how the DDSR operation improves the macroeconomy, or contributes to development. The main purpose of DDSR is to establish a more efficient arrangement between debtor countries and commercial banks, leading to improved conditions for development. A DDSR operation that does not help development is costly and should not be undertaken. The impact of DDSR on development is usually measured by the increase in the growth rate of GDP, but it is too soon to measure that for these five countries. A suitable alternative is to look at the change in investment patterns. A strong policy framework is needed if debt and debt service reduction are to significantly improve development. In Mexico and, to a lesser extent, Venezuela, improved and sustained strong adjustment policies have generated the greatest development benefits. Gains have been less in smaller countries where policies were not as supportive. The author concludes that for a country to benefit from DDSR, it needs significant indirect benefits (such as increased domestic and foreign savings). Direct benefits are likely to be negative because of the commercial banks'financial gains and because DDSR operations are frontloaded. DDSR operations cannot be justified solely by direct benefits and savings in cash flow.Strategic Debt Management,Banks&Banking Reform,Economic Theory&Research,Environmental Economics&Policies,Financial Intermediation
Aswaq al-Aswaq min masari' al-ussaq, Ibrahim al biqa'- I (m.885/1480) : critical edition and commentary
No full textL'amour, le ʿišq «amour-passion» et les histoires d'amants que le sort épargne ou sur lesquels il s'acharne, sont des thèmes qui ont touché et touchent toujours toutes les sociétés, et semblent traverser les siècles sans vieillir. Certaines légendes ont été rapportées oralement, peut-être même chantées au début, puis grâce à l'écriture et à la réécriture, nous pouvons les lire aujourd'hui. Mais on a tendance à privilégier certaines anecdotes, certains poètes des premiers siècles de l'Islam. Les auteurs des siècles plus tardifs ne semblent pas avoir été assez étudiés du moins pour ce thème de l'amour. C'est le cas de notre auteur : Ibrāhīm b.ʿUmar al-Biqāʿī (m.885/1480), dont l'œuvre est impressionnante, plus de quatre vingt dix titres. Il est surtout connu pour ses productions concernant l'exégèse et le hadith. Son côté littéraire demeure inconnu ou presque.Notre recherche porte sur l'édition critique et le commentaire d'un de ses manuscrits intitulé : Aswāq al-Ašwāq min Maṣāriʿ al-ʿUššāq, titre que nous traduisons par : «Des Marchés des Désirs et des Trépas des Amants», œuvre souvent citée par les chercheurs qui s'intéressent à ce thème, mais jamais éditée.Love-passion and lovers stories, which the fate spares or whom it persecutes, are themes which touched all the societies, and seem to cross the centuries without aging. Certain legends were orally reported, may be even sung at the begenning, then thanks to the writing and the rewriting, we can read them today.But we tend to favor certain anecdotes, certain poets or authors of the first ones centuries of the Islam.The authors of the later centuries do not seem to have been studied enough at least for this theme of love.It is the case of our author Ibrāhīm al-Biqāʿī ( d.885 H/ 1440 J-C) whom the work is impressive, more than ninety titles. He is especially known for its productions concerning the exegesis and the hadith. His literary side remains unknown or almost.Our research concerns the critical edition and the comment of one of its manuscripts title : Aswāq al-Ašwāq min Maṣāriʿ al-ʿUššāq, which I translate : «Markets of the desires and the demise of the lovers»
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