On the off-design of a natural gas-fired combined cycle with CO2 capture

During the last 15 years cycles with CO₂ capture have been in focus, due to the growing concern over our climate. Often, a natural gas fired combined cycle with a chemical absorption plant for CO₂ capture from the flue gases have been used as a reference in comparisons between cycles. Neither the integration of the steam production for regeneration of amines in the combined cycle nor the off-design behaviour of such a plant has been extensively studied before.     

Pro Online-Durchsuchung

Zusammenfassung Die rasante Entwicklung des Internets bewirkt neben einer sich verst?rkenden Internationalisierung von Terrorismus und Organisierter Kriminalit?t einen Strukturwandel weltweiter Kommunikation und Datenspeicherung.     

1D selection of 2D objects in head-worn displays

In current desktop user interfaces, selection is usually accomplished easily with a mouse or a similar two-dimensional locator. In wearable computing, however, controlling two dimensions simultaneously gets significantly harder: a change in one dimension results easily in an undesired change in the other dimension as well when the user is occupied with a parallel task – such as walking. We present a way to overcome this problem by applying one-dimensional selection for graphical user interfaces in head-worn displays. Our new interaction technique allows a wearable computer user to perform object selection tasks easily and accurately. The technique is based on a visible circle on the screen. The user controls the circle, altering its radius with a one-dimensional valuator. The midpoint of the circle is in the middle of the screen. The object currently on the perimeter of the circle is highlighted and can be selected. Our preliminary usability evaluation, applying our custom evaluation method designed especially for walking users, indicates that the proposed technique is usable also when walking.     

Electronic Transport in Ultrathin Gold Films on Si(111)

The morphology and electronic transport of ultrathin Au films with thicknesses d = 1 ? 5 monolayers (ML) deposited on Si(111)7 × 7 surfaces is investigated by in situ scanning tunneling microscopy and electrical resistance measurements for temperatures T = 2 ? 300 K. With decreasing film thickness, i.e. decreasing sheet conductance G_s, a transition from a weakly conducting regime described by a logarithmic temperature dependence to an insulating regime occurs. In the insulating regime, the temperature dependence is described by G_s ∝ exp[?(T ₀ /T) ⁿ] with an exponent n which gradually changes from 0.69 to 1 with decreasing film thickness. In contrast, for the Si(111)6 × 6-Au reconstruction obtained after annealing, an exponent n = 1/2 is found suggesting the formation of a soft Coulomb gap due to electron-electron interaction. PACS numbers: 68.37.-d, 68.55.-a, 73.50.-h, 73.25.+i, 81.15.-z     

Replication and bonding techniques for integrated microfluidic systems

From the technical and economic points of view, systems integration, and packaging represent a crucial step in the production of microsystems. Compared to purely silicon- or glass-based systems, the variety of materials and geometries available for purely polymer microfluidic systems is much larger, due to the outstanding material properties. Moreover, polymers may be shaped and joined by comparably simple methods. Examples are polymer microreplication as well as various bonding methods. With them, complete polymer microsystems can be integrated. In addition, a number of established, compatible processes are available for the integration of functional elements that may also be made of other materials.

     

Data in Voice — In-Band Short Messaging Service (SMS) für den analogen Flugfunk

6. Zusammenfassung  In diesem Artikel wurde die Data in Voice-Technologie vorgestellt. DiV ist eine Methode, die es erlaubt, kurze Daten-Messages gemeinsam mit der Sprache im analogen Flugfunkkanal zu übertragen. Man ist bei FREQUENTIS überzeugt, dass man mit dieser Methode viele Nachteile des vorhandenen analogen Flugfunks beseitigen und dadurch die Flugsicherheit wesentlich erh?hen k?nnte.     

Reliability of structures in high dimensions, part I: algorithms and applications

The present paper is concerned with the estimation of structural reliability when a large number of random variables is present. A sampling technique which uses lines in order to probe the failure domain, is presented. The latter is employed in conjunction with a stepwise procedure which makes use of Markov Chains. The resulting algorithm exhibits accelerated convergence.     

Mesa and planar SiGe-HBTs on MBE-wafers

SiGe-HBTs have the potential for outstanding analog and digital or mixed-signal high frequency circuits widely based on standard Si technology. Here we review on MBE grown transistors and circuits. Processes and results of a research-like SiGe HBT and two possible production relevant HBT versions are presented. The high frequency results with f_max and f_T up to 120 GHz and a minimum noise figure of 0.9 dB at 10 GHz demonstrate the advantage of using MBE samples with steep and high base doping and high germanium contents. A comparison to the concept of reported low doped, low germanium and triangular profiled SiGe base layers, realized by UHV-CVD, is given. In addition, some circuit demonstrators of SiGe-ICs will be presented.