Biological network data is plentiful with practically every experimental methodology giving 'network views' into cellular function and behavior. Bioinformatic screens that yield network data include, for example, genome-wide deletion screens, protein-protein interaction assays, RNA interference experiments, and methods to probe metabolic pathways. Efficient and comprehensive computational approaches are required to model these screens and gain insight into the nature of biological networks. This thesis presents three new algorithms to model and mine network datasets. First, we present an algorithm that models genome-wide perturbation screens by deriving relations between phenotypes and subsequently using these relations in a local manner to derive genephenotype relationships. We show how this algorithm outperforms all previously described algorithms for gene-phenotype modeling. We also present theoretical insight into the convergence and accuracy properties of this approach. Second, we define a new data mining problem–constrained minimal separator mining—and propose algorithms as well as applications to modeling gene perturbation screens by viewing the perturbed genes as a graph separator. Both of these data mining applications are evaluated on network datasets from S. cerevisiae and C. elegans. Finally, we present an approach to model the relationship between metabolic pathways and operon structure in prokaryotic genomes. In this approach, we present a new pattern class—biclusters over domains with supplied partial orders—and present algorithms for systematically detecting such biclusters. Together, our data mining algorithms provide a comprehensive arsenal of techniques for modeling gene perturbation screens and metabolic pathways. / Ph. D.

Matching is one of the most fundamental algorithmic graph problems. Many variants of matching problems have been studied on different classes of graphs, the one of special interest to us being the Maximum Cardinality Bipartite Matching in Planar Graphs. In this work, we present a novel sparsification based approach for computing maximum/perfect bipartite matching in planar graphs. The overall complexity of our algorithm is O(n^6/5 log² n) where n is the number of vertices in the graph, bettering the O(n^3/2) time achieved independently by Hopcroft-Karp algorithm and by Lipton and Tarjan divide and conquer approach using planar separators. Our algorithm combines the best of both these standard algorithms along with our sparsification technique and rich planar graph properties to achieve the speed up. Our algorithm is not the fastest, with the existence of O(n log³ n) algorithm based on max-flow reduction. / MS / A matching in a graph can be defined as a subset of edges without common vertices. A matching algorithm finds a maximum set of such vertex-disjoint edges. Many real life resource allocation problems can be solved efficiently by modelling them as a matching problem. While many variants of matching problems have been studied on different classes of graphs, the simplest and the most popular among them is the Maximum Cardinality Bipartite Matching problem. Bipartite matching arises in varied applications like matching applicants to job openings, matching ads to user queries, matching threads to tasks in OS scheduler, matching protein sequences based on their structures and so on. In this work, we present an efficient algorithm for computing maximum cardinality bipartite matching in planar graphs. Planar graphs are sparse graphs and have interesting structural properties which allow us to design faster algorithms in planar setting for problems that are otherwise considered hard in arbitrary graphs. We use a new sparsification based approach where we maintain a compact and accurate representation of the original graph with a lesser number of vertices. Our algorithm combines the features of the best known bipartite matching algorithm for an arbitrary graph with the novel sparsification approach to achieve the speedup.

Thesis (MScEng) -- Stellenbosch University, 1986 / ENGLISH ABSTRACT: High turbulence, high shear forces and high centrifugal forces characterise the flow in hydrocyclones. These characteristics are employed advantageously in the air-sparged hydrocyclone so that a space time of only one second is necessary for effective flotation. Conventional flotation processes on the other hand require a few minutes. Flotation of pyrite from a coarse Witwatersrand ore (100% -300 micron; 92% +38 micron) produces a sulphur recovery of 90% with a sulphur grade of 40% in the concentrate when the content of solids of the slurry feed equals 10%. Higher recoveries up to 93% are possible when slurries with a higher content of solids (e.g. 30%) are used. However, the sulphur grade then decreases to about 35%. Flotation in a batch cell produces a recovery of sulphur of 95% with a sulphur grade of 40%, but in this case a flotation time of 5 minutes is required. A hydrocyclone with a diameter of 50 mm and a length of 410 mm produces optimum results at a slurry feed rate of 35 to 40 l/min and an air-flow rate of 200 l/min. An air-flow rate of about 150 l/min is adequate at slurry feed rates lower than 35 l/min. Flotation of particles finer than 38 micron is more successful at higher slurry feed rates. The optimum flotation of coarse particles (i.e. +106 micron) occurs at lower feed rates. The best flotation results are obtained in the size fraction between 38 and 75 micron, which produces a recovery and content of sulphur of 95% and 51% respectively. A collector concentrate of 160 g/ton, which is thrice the quantity used in conventional processes, is required. The best recoveries at slurry feed rates lower than 35 l/min are obtained when the frother concentrate is low (approximately 20 mg/l). A higher frother concentrate, i.e. between 50 to 60 mg/l, is required at higher feed rates. The air-sparged hydrocyclone may be used effectively for rougher flotation and especially for the flotation of ore finer than 150 micron. The use of a specially designed pedestal can minimize blockage of the underflow. Such a pedestal has been designed and tested successfully. / MINTEK

No description available.

The effects of Electromagnetism on potable water and waste water has been proven in practice but not scientifically proven to the extent that it is accepted by Engineers and Engineering Consultants. The operating principle of magnetic filtration or separation is based on the interaction of electromagnetic fields with the materials under test. Technical water system (TWS) system configuration has been analysed to determine the system characteristics. Three field trials and some laboratory experiments have been reported in this report. Finite element software has been used for the analysis of magnetic field distribution of the TWS system and also for magnetic separation modelling. There is a need to do some more experiments for more convincing and conclusive outcome.

Thesis (MSc.(Metallurgy)--University of Pretoria, 2008. / Includes bibliographical references.

Thesis (Ph.D.)--University of Wollongong, 2006. / Typescript. Includes bibliographical references: leaf 208-224.

Thesis (M.S.)--Rutgers University, 2008. / "Graduate Program in Civil and Environmental Engineering." Includes bibliographical references (p. 79-80).

Les batteries Li-ion sont la technologie de référence pour l'électronique portable, et l'un des objectifs est le développement de cette technologie pour des applications demandant de fortes densités d'énergie, comme la traction. Ce travail, mené dans le cadre du projet Européen AMELIE- Green Car, porte sur deux aspects. Le premier concerne la synthèse et la caractérisation de nouveaux solvants et sels performants et pouvant être utilisés avec des matériaux à haut potentiel tels que LiNi1/3Mn1/3Co1/3O2 ou LiNi0,4Mn1,6O4, en remplacement des électrolytes courants à base de LiPF6 et de carbonates, qui induisent une forte d'autodécharge et présentent des stabilités thermique et chimique insuffisantes. L'utilisation de carbonates, carbamates et sulfonamides fluorés en tant que solvants, permet d'obtenir, pour certaines des formulations évaluées, des performances comparables aux références commerciales, malgré des conductivités inférieures. De plus, la fluoration confère à ces molécules des stabilités thermique et électrochimique améliorées. En ce qui concerne les sels, plusieurs nouvelles structures ont été synthétisées et testées en combinaison avec des solvants commerciaux, avec des résultats intéressants du point de vue de la conductivité et du comportement électrochimique.La deuxième partie de ce travail concerne la mise en forme, par des procédés industriels, de séparateurs minces à base de polymères fluorés, qui présentent des performances comparables aux séparateurs commerciaux. Des membranes denses et poreuses ont été élaborées à partir de plusieurs grades de PVDF. Les membranes poreuses élaborées, présentant des taux de porosité élevés, montrent de faibles tenues mécaniques, deux stratégies de renfort ont ainsi été étudiées : la première via la réticulation des membranes après greffage de groupements polymérisables, la deuxième via l'incorporation de Cellulose Nano Cristalline (CNC), formant un réseau percolant permettant le renfort. Les deux méthodes ont donné des résultats prometteurs sur les membranes denses : le module de conservation augmente entre 2 et 5 fois à 25°C tout en conservant des performances électrochimiques intéressantes. Le transfert de ces propriétés aux membranes poreuses est encore à optimiser ; cependant un renfort partiel a été obtenu pour les membranes composites poreuses, ce qui en fait, en combinaison avec une bonne conductivité (largement au dessus de 1mS/cm) et porosité, des candidats attractifs pour des accumulateurs Li-ion à charge rapide. / Li-ion batteries have become the dominant power storage devices for portable electronics, and researchers are still at work to broaden their field of use to high energy density devices, like cars. Within the framework of the collaborative project AMELIE - Green car, this study articulates along 2 main axes. The first one deals with the synthesis and characterization of new fluorinated solvents and salts to replace, for the use with high potential materials such as LiNi1/3Mn1/3Co1/3O2 or LiNi0,4Mn1,6O4, the commonly used LiPF6 and carbonate-based electrolytes, which suffer from a high self-discharge ratio, and an insufficient thermal and chemical stability. The use of fluorinated carbonates, carbamates, and sulfonamides as solvents provides performances as good as the commercial references, even if we register a visible loss in conductivity. Moreover, the fluorination provides these molecules with higher thermal and electrochemical stabilities. About the salts, several new structures of sulfonamide salts were synthesized and tested in combination with commercial solvents, with interesting results from the point of view of conductivity and the electrochemical stability.The second part of this study deals with the development of thin perfluorinated separators, which could compete with commercial references such as Celgard® separators and whose production could be easily up-scale. To do this, dense and porous separators were prepared from several PVdF grades. Since the porous membranes, the most promising for the battery applications, suffer from a relatively low mechanical strength, 2 reinforcement techniques were also evaluated: the first one consists in cross-linking the polymer after grafting of polymerizable groups; the second one consists in adding Nano Cristalline Cellulose (NCC) particles to form a reinforcing percolating network. Both methods give promising results with dense membranes: a 2- to 5-fold increase of storage modulus is observed at 25°C, in addition to interesting electrochemical properties. The transfer of these promising results to the porous membranes is still to be optimized, but a partial reinforcement was obtained for nano-composites porous membranes, while the good conductivity (still largely superior to 1 mS/cm) and porosity make them attractive options for high charge rate batteries.

Diploma thesis was aimed at testing of five commercial products for separators of lipids. Performed study should to shown that in produts are presented lipase-produducing microoganisms, event. that in products are also lipolytics enzymes as addition. The products was cultivated by solid-state and submerged fermentations and subsequently was tested their properties as is lipolytic activity, the amount of free fatty acids etc. Solid-state fermentation used Tributyrin Agar Base where Tributyrin was used as a substrate. Submerged fermentation used special prepared medium where was olive oil. Methods using in this study served for detection and qualification of lipase-produducing microoganisms in individual products. For detection of lipase-produducing bacterial spieces was used Spirit Blue Agar. In this case was used Tributyrin and Tween 80 as a substrate. Lipolytic activity was measured by spectrophotometry and degradation of lipids was measured titrimetry. Performed study demonstrated that all tested products have ability to degradation of lipids.