Le besoin d\u27information : point de vue de l\u27usager

Communication faite lors de la journée d\u27étude Thémat\u27IC 2006 "Information : besoins et usages

Techno-Economic Evaluation of CO2-Selective Facilitated Transport Membranes for an IGCC Power Plant

Formålet med denne avhandlingen er å presentere en teknoøkonomiskanalyse av fasilliterttransport hulfibermembraner for H2-rensing og karbonfangst for et integrert gassifiserings- kombinertsykluskraftverk. To membranprosesskonfigurasjoner for separering av CO2 og H2 ble analysert for en IGCC-kraftverksapplikasjon. Prosessflytskjemaet ble utviklet i Aspen HYSYS, basert på tilgjengelige prosessdata for et 634 MW brutto kraftverk. Kapital- og driftskostnadene for hver konfigurasjon bestående av kompressorer, motorer, varmevekslere, tanker og membraner ble deretter beregnet ved hjelp av en modulbasert kosttilnærming. Flere variabler innenfor hver prosesskonfigurasjon, for eksempel sweep-strøm, resirkuleringstrykk, rekompresjonstrykk, ble varierte for å analysere effekten av disse på viktige økonomiske beregninger. Dette gir indikasjoner på kostnadsnivået for elektrisitet og nødvendige CO2-prosesseringsinsentiver for at prosjektet skal være levedyktig. Det ble gjennomført en sensitivitetsanalyse av ytterligere variabler også, inkludert membrankostnad og diskonteringssats for å fastslå hvilken innvirkning disse faktorene har på prosjektets økonomiske beregninger. Ved 90% CO2-fangst er en strømkostnad på $143,99, eller en 33$ 128,19 per tonn. Disse beregningene sammenligner seg godt med den mest etablerte adsorpsjonsteknologien, som fanger 90 % av karbonutslippene med en 31 % økning av strømkostnaden.The purpose of this thesis is to present a techno-economic analysis of facilitated transport hollow-fiber membranes for H2 purification and carbon capture at an integrated gasification combined cycle power plant. Two membrane process configurations for separating H2 and CO2 were analyzed in an IGCC power plant application. The process flowsheet was developed in Aspen HYSYS based off available process data for a 634 MW gross power plant. The capital and operating costs for each configuration comprising compressors, drives, heat exchangers, vessels, and membranes were then calculated using a module-based costing approach. Several variables within each process configuration, such as sweep flow, recycle pressure, recompression pressure, were varied to analyze their effect on key financial metrics indicating the cost of electricity and required CO2 processing incentives for the project to be viable. A sensitivity analysis was conducted on further variables including the membrane cost and discount rate to determine the impact these factors have on the project financial metrics. At 90% CO2 capture, a levelized cost of electricity of $143.99, or a 33$128.19 per metric ton. These metrics compare similarly to the established adsorption technology, which captures 90% of carbon emissions at a 31% increase in levelized cost of electricity

Molecular spintronics: Coherent spin transfer in coupled quantum dots

Time-resolved Faraday rotation has recently demonstrated coherent transfer of electron spin between quantum dots coupled by conjugated molecules. Using a transfer Hamiltonian ansatz for the coupled quantum dots, we calculate the Faraday rotation signal as a function of the probe frequency in a pump-probe setup using neutral quantum dots. Additionally, we study the signal of one spin-polarized excess electron in the coupled dots. We show that, in both cases, the Faraday rotation angle is determined by the spin transfer probabilities and the Heisenberg spin exchange energy. By comparison of our results with experimental data, we find that the transfer matrix element for electrons in the conduction band is of order 0.08 eV and the spin transfer probabilities are of order 10%.Comment: 13 pages, 6 figures; minor change

Formal Verification of an Iterative Low-Power x86 Floating-Point Multiplier with Redundant Feedback

We present the formal verification of a low-power x86 floating-point multiplier. The multiplier operates iteratively and feeds back intermediate results in redundant representation. It supports x87 and SSE instructions in various precisions and can block the issuing of new instructions. The design has been optimized for low-power operation and has not been constrained by the formal verification effort. Additional improvements for the implementation were identified through formal verification. The formal verification of the design also incorporates the implementation of clock-gating and control logic. The core of the verification effort was based on ACL2 theorem proving. Additionally, model checking has been used to verify some properties of the floating-point scheduler that are relevant for the correct operation of the unit.Comment: In Proceedings ACL2 2011, arXiv:1110.447

"Art is religion:" Adolf Hoelzel's modernism

Title from PDF of title page, viewed on January 6, 2012Thesis advisor: Frances S. ConnellyVitaIncludes bibliographic references (p. 86-91)Thesis (M.A.)--Dept. of Art and Art History. University of Missouri--Kansas City, 2011This study considers the work of Austrian-born Adolf Hoelzel (1853-1934), an innovative artist and educator whose contributions to German modernism deserve to be reassessed. His intense lifelong search to understand the essence of art led him from the nineteenth-century European academic tradition to the vanguard of twentieth-century abstraction. The universality of his theories was rooted in his understanding of European painting tradition, particularly Gothic and Northern Renaissance painting, as well as the artwork of children and the mentally ill, thus tying his investigations to larger themes of primitivism in European art. Even as his work moved farther away from objective depiction, his recurring evocation of Christian imagery, especially those with small groups of people in reverential poses, reached back to an earlier period of sacred European art, as he pursued the ideal of harmony central to his artistic concerns. Hoelzel has been remembered as an important teacher to a generation of German modernists, such as Oskar Schlemmer and Johannes Itten. However, as the history of modernism is reevaluated, Hoelzel's work, as well as his ideas, reveal themselves to have been in step with and often to have prefigured international developments in twentieth-century art. Through a reworking of the tradition of religious imagery in painting and drawing, and later as a designer of stained-glass works, Hoelzel found a path from nineteenth-century academic narrative to innovative twentieth-century abstraction and created a body of work with a spiritual content in which the abstract expressive qualities of brilliant color were combined in harmonious compositions.College of Arts and SciencesIntroduction -- The artistic means - Universality in art -- "Art is religion" -- Conclusionmonographi

The annealing effect on structural and optical properties of ZnO thin films produced by RF sputtering

In this work, a study of the structure and optical properties of undoped ZnO thin films produced by r.f. magnetron sputtering technique as a function of the growth parameters is reported. Modification under annealing conditions is also analysed. Raman spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction and optical transmittance have been used. From the position of the (002) X-ray diffraction peak and the E2 (high) mode detected in Raman spectra, the residual stress both in the as-grown and in the annealed samples has been estimated

Paper-Based Ambient Ionization Mass Spectrometry Techniques for Regulatory, Environmental, and Agricultural Challenges

Sample collection techniques based on the use of a paper substrate have been used in a variety of applications, perhaps most notably in neonatal screening using dried blood spots. These techniques provide a simple and inexpensive way of collecting material for later chemical analysis. The utility of paper-based sample collection is dramatically enhanced by combining it with ambient ionization techniques for mass spectrometry, generating gas phase ions directly from the paper substrate without the sample preparation and separations typically employed. These ions may then be analyzed by a mass spectrometer to detect the compounds of interest. In this work, two ambient ionization methods are explored for the ionization of samples collected on paper substrates. Paper spray ionization is an ambient ionization technique in which a spray of charged droplets is generated from a piece of paper cut to a sharp point. A custom paper spray ion source has been designed and built, and used to explore the potential of paper spray ionization-mass spectrometry for pesticide residue analysis applications. Additionally, the first commercial paper spray ion source has recently been released. An evaluation unit was characterized and compared to the custom paper spray ion source. Using this commercial system, automated methods were developed and used for analysis of pesticides in a variety of matrices, including residual impurity analysis of pesticide formulations. These formulations are highly challenging matrices that typically require sample clean-up and the use of separation techniques; using paper spray ionization a simple dilution in acetonitrile was sufficient to enable analysis. In addition to paper spray ionization, a novel ionization technique was developed to ionize compounds collected on paper matrices. This technique, nib-based electrospray ionization (nibESI) avoids the need to cut the paper to a sharp point by generating the electrospray from a sharpened fountain pen nib. This technique is characterized and applied to the analysis of therapeutic drugs and nicotine in a variety of different matrices including serum and salivaDoctor of Philosoph

Security Analysis of the German Healthcare Telematics

The objective of this paper is an analysis of security issues of the forthcoming German healthcare telematics infrastructure. The current analysis reevaluates results from a former security analysis conducted in 2007/08 and introduces new results based on the updated specification documents of the German healthcare telematics. As a result, basics for further security analysis activities are given and corresponding security measures to overcome the identified vulnerabilities are derived. Due to the transferability of the healthcare telematics security concept, which is currently applied in Germany, the achieved results might be helpful for worldwide healthcare telematics projects in the future