Adsorption of phenol/tyrosol from aqueous solutions on macro-reticular aromatic and macro-porous polystyrene cross-linked with divinylbenzene polymeric resins

The current work aims at separating by adsorption of low-molecular-weight organic compounds in a nanofiltration concentrate of the olive mill wastewaters. The experimental investigations on adsorption of phenol/tyrosol in single and binary systems were conducted in batch mode by using the commercially available macroporous resins FPX66 and MN202. The structures of such resins were examined by FTIR before and after adsorption. The operating parameters affecting the adsorption process such as resin dosage, contact time, pH, and initial concentration of phenol/tyrosol were investigated. Fast phenol and tyrosol uptakes were observed for both resins. It can be attributed to their physical properties, for instance high specific area and microporous area. The adsorption selectivity of phenol is larger than tyrosol when using FPX66 resin, but smaller if MN202 resin is used. Acidic pH appeared to be always favourable for the adsorption. A synergetic effect between solutes was observed since adsorption of phenol and tyrosol in the binary systems was faster than the individual sorption of each solute. Five isotherms namely Langmuir, Freundlich, DubininRadushkevich, Temkin and Redlich-Peterson were selected to fit the obtained equilibrium experimental data. Finally, desorption of the examined compounds with ethanol (EtOH) allowed a maximum around 85 % of phenol, and equal to 94 % of tyrosol on FPX66 and MN202 resins

Adsorption of phenol/tyrosol from aqueous solutions on macro-reticular aromatic and macro-porous polystyrene cross-linked with divinylbenzene polymeric resins

The current work aims at separating by adsorption of low-molecular-weight organic compounds in a nanofiltration concentrate of the olive mill wastewaters. The experimental investigations on adsorption of phenol/tyrosol in single and binary systems were conducted in batch mode by using the commercially available macroporous resins FPX66 and MN202. The structures of such resins were examined by FTIR before and after adsorption. The operating parameters affecting the adsorption process such as resin dosage, contact time, pH, and initial concentration of phenol/tyrosol were investigated. Fast phenol and tyrosol uptakes were observed for both resins. It can be attributed to their physical properties, for instance high specific area and microporous area. The adsorption selectivity of phenol is larger than tyrosol when using FPX66 resin, but smaller if MN202 resin is used. Acidic pH appeared to be always favourable for the adsorption. A synergetic effect between solutes was observed since adsorption of phenol and tyrosol in the binary systems was faster than the individual sorption of each solute. Five isotherms namely Langmuir, Freundlich, DubininRadushkevich, Temkin and Redlich-Peterson were selected to fit the obtained equilibrium experimental data. Finally, desorption of the examined compounds with ethanol (EtOH) allowed a maximum around 85 % of phenol, and equal to 94 % of tyrosol on FPX66 and MN202 resins

Essais sur la conception de mécanismes et les enchères

Cette thèse est composée de trois essais liés à la conception de mécanisme et aux enchères. Dans le premier essai j'étudie la conception de mécanismes bayésiens efficaces dans des environnements où les fonctions d'utilité des agents dépendent de l'alternative choisie même lorsque ceux-ci ne participent pas au mécanisme. En plus d'une règle d'attribution et d'une règle de paiement le planificateur peut proférer des menaces afin d'inciter les agents à participer au mécanisme et de maximiser son propre surplus; Le planificateur peut présumer du type d'un agent qui ne participe pas. Je prouve que la solution du problème de conception peut être trouvée par un choix max-min des types présumés et des menaces. J'applique ceci à la conception d'une enchère multiple efficace lorsque la possession du bien par un acheteur a des externalités négatives sur les autres acheteurs. Le deuxième essai considère la règle du juste retour employée par l'agence spatiale européenne (ESA). Elle assure à chaque état membre un retour proportionnel à sa contribution, sous forme de contrats attribués à des sociétés venant de cet état. La règle du juste retour est en conflit avec le principe de la libre concurrence puisque des contrats ne sont pas nécessairement attribués aux sociétés qui font les offres les plus basses. Ceci a soulevé des discussions sur l'utilisation de cette règle: les grands états ayant des programmes spatiaux nationaux forts, voient sa stricte utilisation comme un obstacle à la compétitivité et à la rentabilité. Apriori cette règle semble plus coûteuse à l'agence que les enchères traditionnelles. Nous prouvons au contraire qu'une implémentation appropriée de la règle du juste retour peut la rendre moins coûteuse que des enchères traditionnelles de libre concurrence. Nous considérons le cas de l'information complète où les niveaux de technologie des firmes sont de notoriété publique, et le cas de l'information incomplète où les sociétés observent en privée leurs coûts de production. Enfin, dans le troisième essai je dérive un mécanisme optimal d'appel d'offre dans un environnement où un acheteur d'articles hétérogènes fait face a de potentiels fournisseurs de différents groupes, et est contraint de choisir une liste de gagnants qui est compatible avec des quotas assignés aux différents groupes. La règle optimale d'attribution consiste à assigner des niveaux de priorité aux fournisseurs sur la base des coûts individuels qu'ils rapportent au décideur. La manière dont ces niveaux de priorité sont déterminés est subjective mais connue de tous avant le déroulement de l'appel d'offre. Les différents coûts rapportés induisent des scores pour chaque liste potentielle de gagnant. Les articles sont alors achetés à la liste ayant les meilleurs scores, s'il n'est pas plus grand que la valeur de l'acheteur. Je montre également qu'en général il n'est pas optimal d'acheter les articles par des enchères séparées.This thesis is made of three essays related to mechanism design and auctions. In first essay I study Bayesian efficient mechanism design in environments where agents' utility functions depend on the chosen alternative even if they do not participate to the mechanism. In addition to an allocation rule and a payment rule the designer may choose appropriate threats in order to give agents the incentive to participate and maximize his own expected surplus; The planner may presume the type of an agent who does not participate. I show that the solution of the design problem can be found by a max - min choice of the presumed types and threats. I apply this to the design of an efficient multi-unit auction when a buyer in possession of the good causes negative externalities on other buyers.\\ The second essay considers the fair return rule used by the European Space Agency (ESA). It ensures each member state of ESA a return proportional to its contribution, in the form of contracts awarded to firms coming from that state. The fair return rule is in conflict with the principle of free competition since contracts are not necessarily awarded to firms with the lowest bids. This has raised debates on the use of this rule: it is well accepted by small states, but larger states with strong national space programs, see its strict use as an obstacle to competitiveness and cost effectiveness. It is easy to believe that this rule is more costly to the agency than traditional auctions. We show on the contrary that an adequate implementation of the fair return rule may cause it to be less expensive to the agency than the traditional auctions of free competition. We consider the case of complete information where firms' technology levels are common knowledge, and the case of incomplete information where firms observe privately their production costs. In both cases we show that adequate implementation of the fair return rule may help take advantage of asymmetries between countries in order to expect a lower cost than with traditional auctions.\\ Finally, in the third essay I derive an optimal procurement mechanism in an environment where a buyer of heterogeneous items faces potential suppliers from different groups, and is constrained to choose a winning list that is consistent with some exogenous quotas assigned to the different groups. The optimal allocation rule consists of assigning priority levels to suppliers on the basis of their cost reports. The way these priority levels are determined is subjective but known to all before the auction. The individual reports induce scores for each potential winning list. The items are then purchased from one of the lists with the best score, provided it is not greater than the buyer's valuation for the items. I also find that it is not optimal to purchase the items through separate auctions, unless the buyer's valuation is sufficiently high or low

Thorium(IV) and Uranium(IV) Complexes with 2,6-Dipicolinoylbis(N,N-diethylthiourea) Ligands

The reaction of thorium nitrate hydrate with 2,6-dipicolinoylbis(N,N-diethylthiourea), H2Lpic, results in the hydrolysis of the organic ligand and the formation of [Th(2,6-dipicolinolate)2(H2O)4] (1). Hydrolysis can be avoided by the use of [ThCl4(DME)2] (DME = 1,2-dimethoxyethane) as the starting material and the exclusion of water. The product, [Th(Lpic)3]2− (2), crystallizes as diammonium salt in form of yellow crystals in moderate yields. The thorium ion in the complex is nine-coordinate by the central O,N,O donor atoms of three deprotonated {Lpic}2− ligands. The sulfur atoms of the ligands do not bind to the actinide ion, but establish hydrogen bonds to the ammonium counter ions. A similar coordination sphere is also observed in the uranium(IV) complex [UAu2(Lpic)3}] (3), which was obtained from a reaction between H2Lpic, [U2I6(1,4-dioxane)3] and [AuCl(tht)] (tht = tetrahydrothiophene) in the presence of triethylamine. Charge compensation is established by the linear coordination of two Au+ ions between each two sulfur atoms of the ligands. The products have been studied by X-ray diffraction and IR spectroscopy. The actinide ions in both {Lpic}2− complexes have coordination number nine, but establish slightly different coordination spheres

FPGA-based High-Performance Collision Detection: An Enabling Technique for Image-Guided Robotic Surgery

Collision detection, which refers to the computational problem of finding the relative placement or con-figuration of two or more objects, is an essential component of many applications in computer graphics and robotics. In image-guided robotic surgery, real-time collision detection is critical for preserving healthy anatomical structures during the surgical procedure. However, the computational complexity of the problem usually results in algorithms that operate at low speed. In this paper, we present a fast and accurate algorithm for collision detection between Oriented-Bounding-Boxes (OBBs) that is suitable for real-time implementation. Our proposed Sweep and Prune algorithm can perform a preliminary filtering to reduce the number of objects that need to be tested by the classical Separating Axis Test algorithm, while the OBB pairs of interest are preserved. These OBB pairs are re-checked by the Separating Axis Test algorithm to obtain accurate overlapping status between them. To accelerate the execution, our Sweep and Prune algorithm is tailor-made for the proposed method. Meanwhile, a high performance scalable hardware architecture is proposed by analyzing the intrinsic parallelism of our algorithm, and is implemented on FPGA platform. Results show that our hardware design on the FPGA platform can achieve around 8X higher running speed than the software design on a CPU platform. As a result, the proposed algorithm can achieve a collision frame rate of 1 KHz, and fulfill the requirement for the medical surgery scenario of Robot Assisted Laparoscopy.published_or_final_versio

Séroprévalence du virus de l’herpès humain-8 chez des patients VIH positif à l’hôpital général de Yaoundé – Cameroun

L'épidémiologie de l'infection par le virus herpès humain de type 8 (HHV8) associée à celle à VIH, reste encore méconnue au Cameroun, bien quele pays soit considéré comme une zone endémique pour ces deux virus. L’objectif de ce travail était de ressortir le profil de la séroprévalence duHHV8 au sein de notre population d'étude. 57 personnes ont été recrutées à l'Hôpital Général de Yaoundé et suivies sur une durée 12 mois. Desanticorps IgG anti-HHV8 ont été déterminés par ELISA. Des paramètres autres, tels que l'âge, le sexe, le stade des maladies (SK et VIH/SIDA), leprotocole ARV, ainsi que les taux de CD4 ont été utilisés pour déterminer les variables associées à la séropositivité au HHV8. Cette association aété évaluée par le test khi carré. La séroprévalence du HHV8 était de 90% dans notre population en début d'étude et de 74% douze mois plustard, une séroprévalence qui restait élevée quelque soit le profil clinique, la tranche d'âge, le sexe ou le taux de CD4+ de l'individu. Aucune variable de l'étude n'était significativement associée à la séropositivité du HHV8. Le virus HHV8 semblait circuler au sein de notre population d'étude. Cependant l'on constate, douze mois plus tard, l'absence de  manifestations cliniques du SK chez les patients VIH+ positifs, malgré destitres très élevés en IgG anti-HHV8

Signs of the legal regulation of bodies supporting enforcement of economic and other courts in the Soviet period

У статті визначено характерні ознаки правового регулювання діяльності органів, що забезпечували виконання рішень арбітражних та інших судів у радянський період. Названо основні нормативні акти радянського періоду. Виділено характеристики, що можна буде використати при модернізації сучасного українського законодавства.Typical signs of legal regulation of the authorities activities, which ensured enforcement of decisions arbitration and other courts in the Soviet period, have been identified in the article. The basic regulations acts of the Soviet period were identified. Characteristics, that can be used in modernization Ukrainian modern legislation, were allocated

Bis{µ-(2,2′-bipyridine-1κ2N,N′)-(6,6′-dicarbonyl-1κ2O,O′:2κO′)bis(N,N-diethylthioureato-2κS)}(acetato-1κO)(µ-acetato-1κO:2-κO′)(methanol-2κO)thoriumnickel

Reactions of 2,2′-bipyridine-6,6′-dicarbonyl-bis(N,N-diethylthiourea), H2Lbipy, with a mixture of thorium nitrate hydrate and nickel acetate hydrate in methanol with NEt3 as a supporting base yield brown single crystals of the bimetallic complex [ThNi(Lbipy)2(CH3COO)2(MeOH)]. Two 2,2′-bipyridine-centered bis(aroylthioureato) ligands connect the metal atoms in a way that the thorium atom is coordinated by two O,N,N,O donor atom sets, while the nickel atom establishes two S,O chelate rings in its equatorial coordination plane. The metal atoms are connected by a bridging acetato ligand, and their coordination spheres are completed by one methanol ligand (nickel) and a monodentate acetato ligand (thorium). A distorted octahedral coordination environment is established around the Ni2+ ion, while the Th4+ ion is in first approximation a 10-coordinate with a diffusely defined coordination polyhedron

Fe0/H2O Filtration Systems for Decentralized Safe Drinking Water: Where to from Here?

Inadequate access to safe drinking water is one of the most pervasive problems currently afflicting the developing world. Scientists and engineers are called to present affordable but efficient solutions, particularly applicable to small communities. Filtration systems based on metallic iron (Fe0) are discussed in the literature as one such viable solution, whether as a stand-alone system or as a complement to slow sand filters (SSFs). Fe0 filters can also be improved by incorporating biochar to form Fe0-biochar filtration systems with potentially higher contaminant removal efficiencies than those based on Fe0 or biochar alone. These three low-cost and chemical-free systems (Fe0, biochar, SSFs) have the potential to provide universal access to safe drinking water. However, a well-structured systematic research is needed to design robust and efficient water treatment systems based on these affordable filter materials. This communication highlights the technology being developed to use Fe0-based systems for decentralized safe drinking water provision. Future research directions for the design of the next generation Fe0-based systems are highlighted. It is shown that Fe0 enhances the efficiency of SSFs, while biochar has the potential to alleviate the loss of porosity and uncertainties arising from the non-linear kinetics of iron corrosion. Fe0-based systems are an affordable and applicable technology for small communities in low-income countries, which could contribute to attaining self-reliance in clean water supply and universal public health