Search results for "computing"
showing 10 items of 25279 documents
kLa MEASUREMENT IN BIOREACTORS
2010
For accurately measuring kLa in bioreactors the dynamic pressure method (DPM) was introduced by Linek et al. (1993). In this work a simplified version of the same method is discussed. With respect to the original DPM, the simplified version greatly simplifies data treatment. In fact final constant slope observable in the usual semi-log diagram of residual driving force versus time may be simply corrected to obtain the real kLa value with negligible inaccuracy. Experimental data obtained on a lab-size stirred tank reactor confirm all model predictions, including the feature that the adoption of large pressure changes may lead to a better accuracy.
Fabrication and characterization of Metal and Metal Oxide Nanostructures Grown by metal displacement deposition into anodic alumina membranes
2011
Abstract preview not available - see full-text PDF article.
Vortex shape in unbaffled stirred vessels: experimental study via digital image analysis
2011
There is a growing interest in using unbaffled stirred tanks for addressing certain processing needs. In this work, digital image analysis coupled with a suitable shadowgraphy-based technique is used to investigate the shape of the free-surface vortex that forms in uncovered unbaffled stirred tanks. The technique is based on back-lighting the vessel and suitably averaging vortex shape over time. Impeller clearance from vessel bottom and tank filling level are varied to investigate their influence on vortex shape. A correlation is finally proposed to fully describe vortex shape also when the vortex encompasses the impeller.
Analysis and Performance Evaluation of the IEEE 802.16 ARQ Mechanism
2008
The IEEE 802.16 standard defines the ARQ mechanismas a part of the MAC layer. The functioning of the ARQmechanism depends on a number of parameters. The IEEE802.16 specification defines them but it does not provide concrete values and solutions. This paper studies the key features and parameters of the 802.16 ARQ mechanism. In particular, we consider a choice for the ARQ feedback type, an algorithm to build block sequences, the ARQ feedback intensity, a scheduling of the ARQ feedbacks and retransmissions, the ARQ block rearrangement, ARQ transmission window and the ARQ block size. We ran simulation scenarios to study these parameters and how they impact the performance of application protoc…
Serial Production, Serial Photography, and the Writing of History in Three Farmers on Their Way to a Dance.
2010
Three Farmers on their Way to a Dance, titre d’une photographie qu’August Sander prit en 1914, hante le roman éponyme de Richard Powers. Cette photographie faisait partie d’un projet plus vaste, intitulé « Hommes du vingtième siècle » par Sander qui entendait dresser un inventaire des habitants de sa province natale, le Westerwald. Sander composa ainsi un catalogue de plus de 600 photos d’Allemands de tous types, dont il fit plus tard paraître une partie sous le nom de Visage de notre temps. Dans le roman de Richard Powers, le motif de la série se déploie entre les pôles incarnés par Henry Ford et August Sander, dont les séries de voitures et de photographies deviennent la métaphore du mode…
BEST-2K Method for Characterizing Dual-Permeability Unsaturated Soils with Ponded and Tension Infiltrometers
2019
This study presents a new method (BEST-2K) that extends the existing BEST methods for use in characterizing the water retention and hydraulic conductivity functions of matrix and fast-flow regions in dual-permeability soils. BEST-2K requires input information from two water infiltration experiments that are performed under ponded (Beerkan) and unsaturated (tension infiltrometer) conditions at the surface. Other required inputs include water content measurements and the traditional BEST inputs (particle size distribution and bulk density). In this study, first, a flowchart of the BEST-2K method was developed and illustrated with analytically generated data for a synthetic dual-permeability s…
Towards automatic calibration of 2-D flood propagation models
2010
Abstract. Hydraulic models for flood propagation description are an essential tool in many fields and are used, for example, for flood hazard and risk assessments, evaluation of flood control measures, etc. Nowadays there are many models of different complexity regarding the mathematical foundation and spatial dimensions available, and most of them are comparatively easy to operate due to sophisticated tools for model setup and control. However, the calibration of these models is still underdeveloped in contrast to other models like e.g. hydrological models or models used in ecosystem analysis. This has two primary reasons: first, lack of relevant data against which the models can be calibr…
Studies on the zooplankton of the deep subalpine Lake Garda
1999
The specific composition and seasonal dynamics of the zooplankton of Lake Garda have been studied through monthly surveys in two annual cycles (December 1994-November 1995 and January-December 1997). The assemblage is largely dominated by Copipo-diaptomus steueri, a typical calanoid presently identified in deep (Garda, Iseo) and shallow lakes of NE Italy and in the hinterland of the central Adriatic region (Dalmatia and Marche Region). Cladocerans and the smaller rotifers represent a significant component of the zooplankton from spring to autumn. A re-examination of the results obtained in previous studies does not seem to demonstrate substantial shifts in the composition of the dominant sp…
Numerical Investigation of a Wood-Chip Downdraft Gasifier
2019
Biomass gasification is regarded as one of the most promising technology in the renewable energy field. The outcome of such operation, i.e. the synfuel, can be exploited in several ways, for example powering engines and turbines, and is considered more flexible than the biomass itself. For this reason, a careful analysis of the gasification performance is of paramount importance for the optimization of the process. One of the techniques that can be used for such a purpose, is the numerical analysis. CFD is indeed a tool that can be of great help in the design and study of the operation of the gasifier, allowing for an accurate prediction of the operating parameters. In this work, a downdraf…
Santé et biens communs : un regard de juriste
2007
La santé constitue un domaine dans lequel les notions de bien commun ou de bien public mondial sont particulièrement pertinentes. Il faut cependant préciser de quels biens il est question. A titre d’exemple, le droit français comporte des notions susceptibles de qualifier le droit aux soins (comme droit inaliénable), ou le médicament, objet de propriété intellectuelle comme de propriété « traditionnelle ». Un droit international des biens de santé peut de la même manière être fondé sur un droit d’usage de chacun sur la molécule qui est la même dans le médicament générique et celui de marque. Une procédure d’accès équivalent aux produits, brevetés ou non, pourrait être mise en œuvre par prin…