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Darmstadt, Germany

The Technische Universität Darmstadt , commonly referred to as TU Darmstadt is a research university in the city of Darmstadt, Germany. It was founded in 1877 and received the right to award doctorates in 1899. In 1882 it was the first university in the world to set up a chair in electrical engineering, in 1883 the first faculty for electrical engineering was founded there. Wikipedia.

Anisotropy is a basic property of single crystals. Dissimilar facets/surfaces have different geometric and electronic structure that results in dissimilar functional properties. Several case studies unambiguously demonstrated that the gas sensing activity of metal oxides is determined by the nature of surfaces exposed to ambient gas. Accordingly, a control over crystal morphology, i.e. over the angular relationships, size and shape of faces in a crystal, is required for the development of better sensors with increased selectivity and sensitivity in the chemical determination of gases. The first step toward this nanomorphological control of the gas sensing properties is the design and synthesis of well-defined nanocrystals which are uniform in size, shape and surface structure. These materials possess the planes of the symmetrical set {hkl} and must therefore behave identically in chemical reactions and adsorption processes. Because of these characteristics, the form-controlled nanocrystals are ideal candidates for fundamental studies of mechanisms of gas sensing which should involve (i) gas sensing measurements on specific surfaces, (ii) their atomistic/quantum chemical modelling and (ii) spectroscopic information obtained on same surfaces under operation conditions of sensors. © 2010 The Royal Society of Chemistry. Source

Tropea C.,TU Darmstadt
Annual Review of Fluid Mechanics | Year: 2011

Particle characterization in dispersed multiphase flows is important in quantifying transport processes both in fundamental and applied research: Examples include atomization and spray processes, cavitation and bubbly flows, and solid particle transport in gas and liquid carrier phases. Optical techniques of particle characterization are preferred owing to their nonintrusiveness, and they can yield information about size, velocity, composition, and to some extent the shape of individual particles. This review focuses on recent advances for measuring size, temperature, and the composition of particles, including several planar methods, various imaging techniques, laser-induced fluorescence, and the more recent use of femtosecond pulsed light sources. It emphasizes the main sources of uncertainty, the achievable accuracy, and the outlook for improvement of specific techniques and for specific applications. Some remarks are also directed toward the computational tools used to design and investigate the performance of optical particle diagnostic instruments. © 2011 by Annual Reviews. All rights reserved. Source

Kaldenhoff R.,TU Darmstadt
Current Opinion in Plant Biology | Year: 2012

Plants provide an excellent system to study CO 2 diffusion because, under light saturated conditions, photosynthesis is limited by CO 2 availability. Recent findings indicate that CO 2 diffusion in leaves can be variable in a short time range. Mesophyll CO 2 conductance could change independently from stomata movement or CO 2 fixing reactions and it was suggested that, beside others, the membranes are mesophyll CO 2 conductance limiting components. Specific aquaporins as membrane intrinsic pore proteins are considered to have a function in the modification of membrane CO 2 conductivity. Because of conflicting data, the mechanism of membrane CO 2 diffusion in plants and animals is a matter of a controversy vivid debate in the scientific community. On one hand, data from biophysics are in favor of CO 2 diffusion limiting mechanisms completely independent from membrane structure and membrane components. On the other, there is increasing evidence from physiology that a change in membrane composition has an effect on CO 2 diffusion. © 2012 Elsevier Ltd. Source

North Carolina State University and TU Darmstadt | Date: 2015-08-11

Methods, systems, and computer readable media for extending security of an application-based computer operating system are disclosed. One system includes a memory. The system also includes an application-based operating system security module bridge implemented using the memory. The application-based operating system security module bridge is for receiving, from a reference monitor, a registration for at least one security authorization hook, for receiving a callback when a protected event occurs, for communicating with the reference monitor that registered the at least one security authorization hook corresponding to the callback, and for receiving, from the reference monitor, an access control decision associated with the protected event.

A method is described for determining the size of a transparent particle (

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