Mit eLearning zu Medienkompetenz?

Rezension zu Bernd Schorb, Niels Brüggen u. Anke Dommaschk (Hrsg.) Mit eLearning zu Medienkompetenz Modelle für Curriculumgestaltung, Didaktik und Kooperation München: kopaed, 2008. 224 Seiten ISBN: 3-86736-000-

Hinweise zur qualitätsgerechten Planung und Ausführung von Estrich- und Fußbodenkonstruktionen im Wohn-, Gesellschafts- und Industriebau

Fußbodenkonstruktionen als Stiefkind der Planung und Ausführung? Bei der Ausführung von Fußböden gibt es viele Fehlerquellen. Ein umfassendes Kompendium mit Hinweisen aus der Praxis für die Planung und Ausführung von Fußböden ist im Jahr 2000 mit dem FUSSBODENATLAS erschienen; die vorliegende Veröffentlichung wurde in Auszügen diesem Werk entnommen

Bildungspotenziale digitaler Spiele und Spielkulturen

Der Beitrag konzentriert sich auf den Bereich des informellen und selbstgesteuerten Lernens im Kontext von Computerspielen und Computerspielkulturen und verfolgt das Ziel, ausgehend von einer Untersuchung ausgewählter Bildungspotenziale Grundlagen für die Einschätzung und Bewertung von Computerspielen sowie ihren Einsatz in pädagogischen Kontexten anzubieten. Es wird dazu zunächst begrifflich zwischen Lernen und Bildung unterschieden, um einer engen instrumentellen Perspektive zu entkommen. Anschliessend werden unterschiedliche Arten von digitalen Bildungsräumen thematisiert, bevor spezifische Bildungspotenziale von Singleplayer-Spielen und von community-basierten Multiplayer-Spielen genauer erläutert und diskutiert werden. Abschliessend plädiert der Beitrag dafür, die Kluft zwischen formalen und informellen Lernumgebungen zu überbrücken

Different facets of compulsive buying among Chinese students

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Digitalisierung oder Mediatisierung? Ein analytischer Blick auf die Transformation sozialpädagogischer Arbeitsfelder

Die Digitalisierung stellt aktuell einen der zentralen gesellschaftlichen Wandlungsprozesse dar, der über die Institutionen bis in die Praxis der Sozialen Arbeit hineinwirkt und letztlich auch deren Selbstverständnis betrifft. Dabei zeigt sich die Digitalisierung als technizistisch und ökonomisch geprägt und impliziert einen entsprechenden Wandel der Sozialen Arbeit. Durch die Anknüpfung an die Mediatisierungstheorie wird im vorliegenden Beitrag eine alternative Perspektive auf den digitalen Wandel entfaltet, die es erlaubt, die (dialogische) Kommunikation und nicht die technische Infrastruktur als den eigentlichen Kern sozialpädagogischer Praxis bei der Analyse in den Blick zu nehmen und von hier aus alternative Gestaltungsoptionen zu skizzieren, was am Beispiel der Transformation der Beratung durch Mediatisierung entfaltet wird. (DIPF/Orig.

Air Coupled Ultrasonic Transducers for Industrial Applications

Air-coupled ultrasonic transducers are widely used in many industrial, medical, or domestic applications, such as range finding, gesture sensing, or gas flow metering, to name only a few. The knowledge of the behavior and properties of the ultrasonic transducers is essential for the development and the improve- ment of these applications. The three most utilized work principles, e.g. piezoelectric, electrostatic, and electromagnetic, of ultrasonic transducers are explained and most common representatives of ul- trasonic transducers are described. Within this thesis, several important methods of characterization in three domains (electrical, mechanical, and acoustical) of ultrasonic transducers are described, investig- ated and modified. The electrical impedance measurement delivers the most important characteristics of ultrasonic transducers in the electrical domain. However, the electrical impedance measurement us- ing a common network analyzer reveals issues considering the measurement uncertainties at higher impedance values, such as the open circuit resonance frequency. In order to characterize the behavior of the ultrasonic transducers with the boundary conditions more closely to the applications, electrical impedance measurements of ultrasonic transducers at their rated excitation voltage are conducted in comparison to the common small signal network analyzer measurements. Further, the ultrasonic trans- ducers are characterized with thermal loads, which occur, for example, in gas flow metering. A wide temperature range of almost 450°C from −190°C using a cryo setup to +250°C using an oven are used to characterize a piezoelectric wide range transducer. In doing so, the influence of the excitation voltage and the thermal boundary conditions are investigated. A complex curve fit algorithm is implemented in MATLAB® and is used to fit the Butterworth-van Dyke model to the electrical impedance data gathered. The Butterworth-van Dyke model is extended by using up to seven parameters in total in order to de- scribe additional physical effects such as contact resistance, parasitic contact capacitance, and parasitic parallel resistance. The parameters are monitored and each of them is analyzed individually to achieve a robust complex curve fit algorithm. A laser doppler vibrometer is used to characterize the surface velo- city and displacement of the ultrasonic transducers in the mechanical domain. This measurement setup is extended by translational linear stages in order to obtain the surface velocity of the entire surface area of ultrasonic transducers. Through post processing of the stored A-scans at any spatial point of the area, characteristics such as the transient oscillation at each point, are visualized in a video sequence. In order to characterize ultrasonic transducers in the acoustical domain, two different volumetric sound pressure level measurement systems are used to characterize and visualize the sound pressure field using a calibrated microphone. First, a 3D linear stage which is capable of measuring the sound pressure level in a volume of 1m³ in front of an ultrasonic transducer in equidistant steps in any direction ( X − Y − Z ). Second, a goniometer which is built in an anechoic chamber and capable of measuring the sound pres- sure level in a volume of 144π m³ in front of an ultrasonic transducer, using spherical coordinates r-ϕ-θ. Further, an air-coupled 40kHz 1D-phased array prototype with a half-wavelength pitch is built and char- acterized in both transmit and receive mode. It features a smart packaging layer utilizing waveguides to separate the acoustic aperture from the vibrating aperture. In doing so the acoustic characteristics are manipulated and an impressive sound pressure level of (130 ± 1)dB at a distance of 1m. The ultrasonic beam can be steered electronically in an angle of 110°without creating any significant grating lobes. IIThe approach, used in this prototype, leads to various improvements of existing applications, such as gestures sensing, gas flow meters, or imaging of entire rooms in air. Further, the mechanical amplific- ation, using an additional horn structure on top of the vibrating aperture, of the efficient piezoelectric Murata MA40S4x ultrasonic transducers is investigated and adopted. A capacitive micromachined ultra- sonic transducer is modified with such a horn structure acting as a mechanical amplifier. The horn with a diameter of 2.3mm and a thickness of 100µm is fabricated of aluminum using non-micromachining techniques. It is glued on top of a 55kHz single cell device and an increased sound pressure level of (3 ± 1)dB is obtained. Within this thesis the described methods of characterizations are essential to gain needed knowledge of the behavior of ultrasonic transducers, which can lead to an improvement of many industrial, medical, or domestic applications. The described waveguide approach and mechan- ically amplification opens the door for various modification of ultrasonic transducers and therefore the usage in applications

How the economic situation moderates the influence of available money on compulsive buying of students — a comparative study between Turkey and Greece

Abstract Background and aims Few studies about compulsive buying consider the economic framing situation. This study is concerned with the impact of different economic environments — the crisis in Greece vs. the boom in Turkey — on compulsive buying tendencies of students, while taking the role of gender and available money into account. Methods Compulsive buying was measured by a Greek and Turkish translation of the German Compulsive Buying Scale (Raab, Neuner, Reisch &amp; Scherhorn, 2005) in Greece and Turkey, which enabled an identification of compulsive and compensatory buyers. The questionnaires were administered to 119 Turkish and 123 Greek students (n = 242) enrolled in several universities in Athens and Istanbul. The data collection was conducted in a controlled and standardized way, namely in group-sessions lasting about 5 minutes, which were conducted and supervised by co-workers of the involved universities. Results The results have shown that the percentage of compensatory buyers, but not compulsive buyers, within the Greek students sample was significantly smaller than within the Turkish student sample. Further as assumed the moderation of the economic situation could be confirmed: More available money only has a facilitating effect on compulsive buying tendencies under a positive economic environment. Conclusions Anticipations about the financial situation and the general economic climate are more relevant for compulsive buying tendencies than one's actual available money. Compensatory, but not compulsive buying was significantly smaller under crisis

Construction of a Compact, Versatile Diode Laser Spectrometer and Characterization of Dye-Surfactant Interactions

A compact diode laser spectrometer has been designed and built. A diode laser serves as a light source. The sample holder was designed to allow the mounting of optical filters and focusing optics. These optical filters differentiate between transmitted, scattered, and fluorescent light. A photodiode transduces one of these optical signals to a current signal. The electronics were designed to perform current to voltage conversion, amplify the signal, and filter out noise. Further processing and display are performed by a Virtual Instrument , which is a computer program designed to simulate a physical instrument. Design methodology for the mechanical/optical, electronic, and software aspects of the work is include in the thesis