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This study focuses on the experimental and numerical investigations on a commercial Ranque-Hilsch vortex tube. Ranque-Hilsch vortex tubes have many applications in industry and production as they can generate a very cold flow just from pressurized air .e.g. machine tool cooling. Main objective of this study is the energy separation in the flow field which results in a temperature drop on the cold exit of the tube. This was investigated experimentally by measuring the outlet temperature on the cold exit and the pressure drop on the flow restrictor valve on the hot exit. At a pressure drop of 0.5 bar the vortex tube showed the best performance by reaching a cold exit temperature of –16.7 °C. The Inlet flow was pressurised air at 20 °C and 6 bar.<br /> The numerical analysis was carried out by full 3D steady state CFD-simulation using the commercial software ANSYS CFX 11.0. The three dimensional model represented a 120° sector of the tube using periodic boundary conditions. A comparison between different turbulence models (k – å, RNG k – å, k – ù, SST) was carried out. The classic k – å two layer turbulence model showed the best results compared to the experiment. The energy separation and the drop in cold exit temperature are highest when the viscous work term is included into the energy equation. These effects of including the viscous work term into the energy separation have also been investigated.
Recent developments in information and communication technology, along with advanced displaying techniques and high computational performance open up new visualisation methods to both scientists and lecturers. Thus simulations of complex processes [1] can be computed and visualised in image sequences. The particular idea in our approach is the outsourcing of computationally intensive calculations to servers which then send the results back to mobile users. In order to improve interpretations of the visualised results, users can view them in a 3D-perspective or stereoscopically, given the technical requirements. Today’s technology even permits to view these visualisations on a mobile phone. An example for such a computationally intensive calculation originating from the theory of relativity is depicted in Figure 4.1-1.
The developed solution enables the presentation of animations and 3D virtual reality (VR) on mobile devices and is well suited for mobile learning, thus creating new possibilities in the area of e-learning worldwide. Difficult relations in physics as well as intricate experiments in optics can be visualised on mobile devices without need for a personal computer.
The idea of this game is to use a flashcard system to create a short story in a foreign language. The story is developed by a group of participants by exchanging sentences via a flashcard system. This way the participants can learn from each other by knowledge sharing without fear of making mistakes because the group members are anonymous. Moreover they do not need a constant support from a teacher.
After Image
(2013)
Diffusion plays a decisive role in brain function. In treating brain disorders, where diffusion is often compromised, understanding the transport of molecules can be essential to effective drug delivery. It became apparent that the classical laws of diffusion, cast in the framework of porous media theory, can deliver an accurate quantitative description of the way that molecules are transported through the brain tissue.
Komplexe optische Netzwerke fordern eine immer größere Anzahl an permanenten und dämpfungsarmen Glasfaserverbindungen (Spleiße). Eine wichtige Voraussetzung für hochqualitative Spleiße ist eine geeignete Temperaturverteilung. Die Autoren stellen eine In-situ-Methode zur Temperaturkontrolle durch Bildbearbeitung vor.
Alexander von Humboldt’s maps, graphs and illustrations contain a great deal of detail, but in the available rare editions they are hardly visible to the naked eye. In many editions they have been reduced. In a digital library, they will become accessible in their entirety, and Internet technology will reproduce them in a form that overcomes the limitations of the original printing. The user will be able to enlarge the images and see details that might have been overlooked in the past. The Humboldt’s digital library will adhere to the standards for digital libraries established by the Open Archives Initiative (OAI) and the tools EPRINTS and DSPACE to provide the Web services and determine the most effective way to establish dynamic linking and knowledge based searching of information within the archive.
After approximately 200 years, a comprehensive access to the texts of Humboldt’s extraordinary exploration of the Americans is within sight. To open the legacy to the public for free access the Humboldt Digital Library (HDL) project has been developing a dynamic amount of data related to studies of Alexander von Humboldt. The library includes a range of texts, tables and images, as well as many tools that assist mining the data and navigating the system.
After approximately 200 years, a comprehensive access to the texts of Humboldt's extraordinary exploration of the Americans is within sight. To open the legacy to the public for free access the Humboldt Digital Library (HDL) Project has been developing a dynamic amount of data related to studies of Alexander von Humboldt. The Library includes a range of texts, tables and images, as well as many tools that assist mining the data and navigating the system.
The HDL aims to provide an environment in which researchers can work more effectively with a wider variety of primary source materialsùtextual as well as visual. Moreover, the greatest advantage of this dynamic system is its capability to connect data from diverse locations in Humboldt's twenty-nine volumes and allow comparison with modern scientific knowledge and developments.
HDL can recreate the context of a particular text, making it possible to view images, geo-referenced and interactive maps, information about plants and animals, as well as scientific data relevant to Humboldt's observations. By introducing Web 2.0 technology implementations, we are providing new visualizations of the information published in this Digital Library. The perception of the Information Architecture is changing in the era of Web 2.0. By providing more search facilities, creating an academic network around our library and implementing new ways of multi-dimensional navigation we argue that Information Architecture can be extended to new methods of information representation. Facilitating the user navigation to the required information will always be an aim for the managers of high volume data systems. This can be achieved by implementing Information Retrieval modules based on user profiling and by improving the visualization features.
The need of suitable system of records in gaining ground as companies seek to maximize performance by harnessing the knowledge of their businesses, is discussed. Focused systems of record deliver a clear and consistent view even as they address a range of functions. Enterprise resource planning (ERP), as the financial system of record, embodies that view of manufacturing, inventory management, accounting and order processing. Customer relationship management (CRM), as a system of record, taps not only into the marketing and sales and service, but also into product development.
Innovative combined heat, cold and power (Trigeneration) at Offenburg University of Applied Sciences
(2013)
Im Rahmen dieser Arbeit wird ein „lowcost“ System für smarthome-Anwendungen vorgestellt. Die Steuerung der smarthome-Komponenten erfolgt durch einen Appliance-Controller auf Basis des FS20 Protokolls, wogegen die „Intelligenz“ des Systems durch eine mobile Anwendung (Android-OS) realisiertwird. Durch Auslagerung der Rechenleistung und der Benutzerschnittstelle auf das smartphone kann eine kostengünstige Alternative zur bestehenden Smarthome-Systemen aufgezeigt werden, die durch Einbindung externer Anwendungen leicht erweitert werden kann.
In short-reach connections, large-diameter multimode fibres allow for robust and easy connections. Unfortunately, their propagation properties depend on the excitation conditions. We propose a launching technique using a fibre stub that can tolerate fabrication tolerances in terms of tilts and off-sets to a large extent. A study of the influence of displaced connectors along the transmission link shows that the power distributions approach a steady-state power distribution very similar to the initial distribution established by the proposed launching scheme.
Under a grant of the German ProInno program („Erhöhung der Innovationskompetenz mittelständischer Unternehmen“)the Hochschule Offenburg participated during the past 2 years in an industry project prototyping a new type of service for modern Air Traffic Control (ATC) applications.<br> Objective of the project has been the joint development of hardware and software components for a so-called TIS-B (Traffic Information System - Broadcast) support infrastructure to enable new cockpit applications increasing the air situation awareness for pilots of commercial airliners [1]. At the core of the project is a space-time-scheduler, controlling a battery of TIS-B groundstations over a Wide Area Surveillance Network [4].<br> The project has been successfully concluded and is currently in its evaluation phase. Industry partner was the Karlsruhe-located company COMSOFT, international market leader in ATC sensor networks.
Air traffic control today still works primarily with classical sensors like primary and Secondary Surveillance Radars (PSR, MSSR, Mode-S) [1]. Upcoming is a new technology, ADS (Automatic Dependent Surveillance), which derives positional information from a Global Navigation Satellite System (GNSS) and distributes this data together with additional information from the on-board Flight Management System (FMS) to other aircraft (air-to-air) and to ADS groundstations (air-to-ground). [2] Because the transmission of the data takes place on a shared broadcasting media, like the 1090 MHz Extended Squitter (ES) channel, the technology is also referred to as ADS-Broadcast (ADS-B).
Cardiac resynchronisation therapy (CRT) is a promising treatment option in patients with chronic heart failure. In this article the roles of semi-invasive esophageal left-heart electrocardiography and functional cardiac nuclear imaging in the field of CRT are highlighted, as the combination of both could be a favourable diagnostic approach in special cardiac situations. Also original esophageal left heart electrogram data of exemplary CRT patients is presented.
Active Noise Control (ANC) systems have proved to be a very efficient way to reduce low-frequency acoustic noise. On this domain, passive techniques like enclosures, barriers and silencers tend to be relatively large, costly and ineffective. Although many studies and articles have been published in order to improve performance and stability, the implementation of a real-time, stable and robust system still faces several theoretical and practical challenges.
Prof. Gitte Lindgaard, from the University of Carleton, Canada, says that viewing only some milliseconds of the first page of a website defines our general opinion about it [1]. For an online-shop, it would therefore be essential to have a first page that is not only pleasing to the eye, but also understandable enough to not loose the attention of the user. More and more companies are nowadays using the Internet not only as a showcase anymore, but as a full-strength selling tool, needing thus to convince their users and clients at first glance. This paper shows the analysis of two online-shops in the magazines’ field thanks to eye-tracking. With the analysis of the testers’ glances and their comments during and after the test, the usability of these two websites has been evaluated.
When a new product is produced, it makes sense, to test the usability before its appearance on the market. Within such a test there are different methods which can be used. For example, the eyetracking method. This research report illustrates how the eyetracking method can be used in combination with a qualitative inquiry to identify problems of a product. The study was conducted in cooperation with the company K+UPrintwareGmbH in Ettenheim. The object of the study was the EcoCash recycling and selling machine. The main element of this study is the identification of problems in the user interface and the handling of the machine. Furthermore, solutions to solve the problems were included.
Bluetooth personal area networks (PANs) share the 2.4 GHz ISM spectrum with the IEEE 802.11b wireless local area networks (WLANs). With the popularity of wireless devices, this ISM spectrum is becoming more and more crowded. As a result of this interference between WLANs and PANs, the performance of each network is decreased. Current research has not significantly covered the degrading impact of an 802.11b interferer on Bluetooth voice transmission. Within this project, simulations were carried out to precisely study the impact of an 802.11b interferer on the performance of Bluetooth voice transmission at different ratio levels of Bluetooth power to WLAN power at the receiver side. Furthermore, the impact of SNR on the Bluetooth voice performance and the benefit of using the SCORT packet type was analysed as well. Based on the results presented, network performance can be evaluated at the desired activity level.
Radio frequency (RF) power amplifiers (PA) are the most power consuming components of a mobile communications unit. They are used to convert the DC power from the battery into RF power delivered to the antenna. In a cell phone it becomes very important to use highly efficient power amplifiers, such as Class C and Class E PAs, to increase the talk time which is directly proportional to the battery life. On the other hand, these RF PAs are inherently nonlinear and produce spectral regrowth and other undesirable effects.
Home Automation, Smart Metering, reduction of energy consumption for climate preservation – those buzz words are flooding the daily press.The European Directive 2006/32/EC (Energy-Use Efficiency and Energy Services) commits its members to reduce their energy consumption about nine percent from 1996 to 2015, and supports smart metering and the need of new developments for encouraging energy efficiency and CO² reduction in households and commercial buildings. The European countries have started different projects to achieve this goal. Also outside Europe, smart metering gains interest, for energy savings and better distribution network control.
Rudolf E. Kaiser
(2020)
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