Home About us Contact
|
Home About us Contact | ||
|
|
||
Detailed View (detailed + view)
Selected AbstractsA Simple Correction for Slug Tests in Small-Diameter WellsGROUND WATER, Issue 3 2002James J. Butler Jr. A simple procedure is presented for correcting hydraulic conductivity (K) estimates obtained from slug tests performed in small-diameter installations screened in highly permeable aquifers. Previously reported discrepancies between results from slug tests in small-diameter installations and those from tests in nearby larger-diameter wells are primarily a product of frictional losses within the small-diameter pipe. These frictional losses are readily incorporated into existing models for slug tests in high-K aquifers, which then serve as the basis of a straightforward procedure for correcting previously obtained K estimates. A demonstration of the proposed procedure using data from a series of slug tests performed in a controlled field setting confirms the validity of the approach. The results of this demonstration also reveal the detailed view of spatial variations in K that can be obtained using slug tests in small-diameter installations. [source] Late Quaternary depositional history of the Reuss delta, Switzerland: constraints from high-resolution seismic reflection and georadar surveysJOURNAL OF QUATERNARY SCIENCE, Issue 2 2002Frank O. Nitsche Abstract Glacial erosion has caused overdeepening of many alpine valleys. After retreat of the ice, they were filled with heterogeneous deposits of glacial, lacustrine and fluvial sediments. A typical example of such a valley segment and its infill is the Reuss delta on the southern shore of Lake Lucerne in Switzerland. To obtain a detailed three-dimensional image of this valley segment, the ETH Institute of Geophysics has acquired several two-dimensional, high-resolution seismic and georadar profiles, and conducted a three-dimensional georadar survey. Interpretations of these geophysical data were constrained by a geological core extracted from a borehole 300 m deep near the investigation site. The seismic profiles imaged ca. 600 m of sediment infill above bedrock. Based on their reflection characteristics, five different deposition units were distinguished. These units were interpreted as a succession of clay/silt at the base, followed by different sand units with variable but generally increasing amounts of gravel. This succession represented a prograding delta that filled the southern part of Lake Lucerne. The latest fluvial development of the region is best represented by the georadar data. In particular, the three-dimensional georadar data set provides a detailed view of an ancient braided river channel Copyright © 2002 John Wiley & Sons, Ltd. [source] Using software trails to reconstruct the evolution of softwareJOURNAL OF SOFTWARE MAINTENANCE AND EVOLUTION: RESEARCH AND PRACTICE, Issue 6 2004Daniel M. German Abstract This paper describes a method to recover the evolution of a software system using its software trails: information left behind by the contributors to the development process of the product, such as mailing lists, Web sites, version control logs, software releases, documentation, and the source code. This paper demonstrates the use of this method by recovering the evolution of Ximian Evolution, a mail client for Unix. By extracting useful facts stored in these software trails and correlating them, it was possible to provide a detailed view of the history of this project. This view provides interesting insight into how an open source software project evolves and some of the practices used by its software developers. Copyright © 2004 John Wiley & Sons, Ltd. [source] Looking inside the box: bacterial transistor arraysMOLECULAR MICROBIOLOGY, Issue 1 2008Thomas S. Shimizu Summary One often compares cells to computers, and signalling proteins to transistors. Location and wiring of those molecular transistors is paramount in defining the function of the subcellular chips. The bacterial chemotactic sensing apparatus is a large, stable assembly consisting of thousands of receptors, signal transducing kinases and linking proteins, and is responsible for the motile response of the bacterium to environmental signals, whether chemical, mechanical, or thermal. Because of its rich functional repertoire despite its relative simplicity, this chemosome has attracted much attention from both experimentalists and theoreticians, and the bacterial chemotaxis response becoming a benchmark in Systems Biology. Structural and functional models of the chemotactic device have been developed, often based on particular assumptions regarding the topology of the receptor lattice. In this issue of Molecular Microbiology, Briegel et al. provide a detailed view of the receptor arrangement, unravelling the wiring of the molecular signal processors. [source] Unfolding the fold of cyclic cysteine-rich peptidesPROTEIN SCIENCE, Issue 3 2008Amarda Shehu Abstract We propose a method to extensively characterize the native state ensemble of cyclic cysteine-rich peptides. The method uses minimal information, namely, amino acid sequence and cyclization, as a topological feature that characterizes the native state. The method does not assume a specific disulfide bond pairing for cysteines and allows the possibility of unpaired cysteines. A detailed view of the conformational space relevant for the native state is obtained through a hierarchic multi-resolution exploration. A crucial feature of the exploration is a geometric approach that efficiently generates a large number of distinct cyclic conformations independently of one another. A spatial and energetic analysis of the generated conformations associates a free-energy landscape to the explored conformational space. Application to three long cyclic peptides of different folds shows that the conformational ensembles and cysteine arrangements associated with free energy minima are fully consistent with available experimental data. The results provide a detailed analysis of the native state features of cyclic peptides that can be further tested in experiment. [source] Experimental and computational study of the bed dynamics of semi-cylindrical gas,solid fluidized bedTHE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 1 2009A. Sahoo Abstract With computational fluid dynamics (CFD) it is possible to get a detailed view of the flow behaviour of the fluidized beds. A profound and fundamental understanding of bed dynamics such as bed pressure drop, bed expansion ratio, bed fluctuation ratio, and minimum fluidization velocity of homogeneous binary mixtures has been made in a semi-cylindrical fluidized column for gas,solid systems, resulting in a predictive model for fluidized beds. In the present work attempt has been made to study the effect of different system parameters (viz., size and density of the bed materials and initial static bed height) on the bed dynamics. The correlations for the bed expansion and bed fluctuations have been developed on the basis of dimensional analysis using these system parameters. Computational study has also been carried out using a commercial CFD package Fluent (Fluent, Inc.). A multifluid Eulerian model incorporating the kinetic theory for solid particles was applied in order to simulate the gas,solid flow. CFD simulated bed pressure drop has been compared with the experimental bed pressure drops under different conditions for which the results show good agreements. La simulation par ordinateur de la dynamique des fluides (CFD) permet de décrire le comportement des écoulements dans les lits fluidisés. Une étude fondamentale et approfondie de la dynamique de lit, tels la perte de charge de lit, le taux d'expansion de lit, le taux de fluctuation de lit et la vitesse de fluidisation minimale de mélanges binaires homogènes, a été réalisée dans une colonne fluidisée semi-cylindrique pour des systèmes solides de gaz, permettant d'obtenir un modèle prédictif pour les lits fluidisés. Dans le présent travail, on a tenté d'étudier l'effet de différents paramètres de système (à savoir, la taille et la masse volumique des matériaux de lit et la hauteur statique initiale de lit) sur la dynamique de lit. Des corrélations ont été établies pour l'expansion de lit et les fluctuations de lit en s'appuyant sur l'analyse dimensionnelle de ces paramètres de système. Une étude par ordinateur a également été menée à l'aide du logiciel commercial de CFD Fluent (Fluent, Inc.). Un modèle eulérien multifluide faisant appel à la théorie cinétique pour les particules solides a été utilisé afin de simuler l'écoulement gaz-solides. La perte de charge de lit simulée par la CFD a été comparée à la perte de charge de lit expérimentale dans différentes conditions et les résultats montrent un bon accord. [source] LambdaXtreme® transport system: R&D of a high capacity system for low cost, ultra long haul DWDM transportBELL LABS TECHNICAL JOURNAL, Issue 2 2006Daniel A. Fishman The LambdaXtreme® Transport System, Lucent Technologies' ultra long haul high-capacity transport product, leverages leading edge innovations in optics and applied physics as well as computational and computer science. In this paper, we provide a detailed view of the research and development efforts that resulted in a lightwave transmission system that is now being used in backbone national networks in the United States. © 2006 Lucent Technologies Inc. [source] Monellin (MNEI) at 1.15,Å resolutionACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 3 2007J. R. Hobbs The X-ray crystal structure of a single-chain monellin protein (MNEI) has been determined at 1.15,Å resolution. The model was refined to convergence employing anisotropic displacement parameters and riding H atoms to produce a final model with Rwork and Rfree values of 0.132 and 0.162, respectively. The crystal contains a single MNEI protein in the asymmetric unit and unusually lacks the dimer interface observed in all previous crystal structures of monellin and its single-chain derivatives. The high resolution allowed a more detailed view of MNEI than previously possible, with 38 of the 96 residues modelled with alternative side-chain conformations, including four core residues Thr12, Cys41, Leu62 and Ile75. Four stably bound negative ions were also located, providing new insight into potential electrostatic interactions of MNEI with the largely negatively charged surface of the sweet taste receptor T1R2,T1R3. [source] | |||||||||||||