The Comparison of High and Low Shear Viscometers for Determining Rheological Characteristics in Pigmented Coatings

Introduction The purpose of this investigation was to determine if there was any relationship between the rheograms of the Hercules High Shear Viscometer and the Stormer Low Shear Viscometer when applied to paper pigmented coatings

Use of Social Network Platforms by E-Learning Professionals in Higher Education: an Empirical Study

Das Informationsportal «e-teaching.org» richtet sich an E-Learning-Akteure/-innen an Hochschulen, denen es Bildungsinhalte und aktuelle Informationen zu didaktischen, technologischen und organisatorischen Aspekten des Lernens mit digitalen Medien bietet. In den Monaten Juli und August 2014 nahmen 137 Nutzer/innen an einer halb-standardisierten, nicht-repräsentativen Online-Befragung teil, welche die Bedeutung sozialer Netzwerke für das Portal in Hinblick auf Austausch- und Informationsprozesse in beruflichen und privaten Kontexten erhob. Zudem wurde das Twitternetzwerk des Portals mit rund 40.000 Verbindungen zwischen 1.600 Personen (Stand: April 2014) anhand einer sozialen Netzwerkanalyse untersucht. Es deutet sich an, dass soziale Netzwerke zu bestimmten Zwecken professionell genutzt werden. Bei der Mehrzahl der Befragten ist dies auf Twitter die gegenseitige Vernetzung sowie die Informationsaufnahme und -streuung, wohingegen auf Facebook die Teilnahme und der soziale Austausch in Gruppen dominiert. Mit rund einem Drittel sieht allerdings ein nicht unerheblicher Teil der Befragten von einer beruflichen Beteiligung in sozialen Netzwerken ab und nutzt stattdessen lieber E-Mails, Blogs und RSS-Feeds.The non-commercial information portal «e-teaching.org» addresses professionals in technology-supported learning in higher education institutions. It publishes educational content and frequent news regarding didactical, technological and organisational aspects of learning with digital media. In July and August 2014, 137 portal users participated in a semi-standardised, non-representative survey, which collected data on the usage behavior and on the perceived importance of social networks for communication and information processes in professional and personal contexts. In addition, the Twitter network of e-teaching.org, which contains about 40.000 links between 1.600 persons (as of April 2014), was investigated through social network analysis methodology. Results suggest that social networks are used professionally for particular purposes. On Twitter, for a majority, networking and the collection and dissemination of information are of most importance, while on Facebook the participation and discussion in groups seems to be the dominant motive. Approximately one third of e-learning professionals are not using social media much for their job, rather relying on e-mails, blogs and RSS feeds

Partizipative Medienkulturen

Rezension zu: Biermann, Ralf, Johannes Fromme, und Dan Verständig, Hrsg. 2014. Partizipative Medienkulturen: Positionen und Untersuchungen zu veränderten Formen öffentlicher Teilhabe. Medienbildung und Gesellschaft, Band 25. Wiesbaden: Springer VS

The Effect of Kinesthetic and Demonstration Techniques of Instruction Upon Standing Broad Jump Performance

A test of standing broad jump ability was administered to ninety-three sixth grade boys to compare the kinesthetic and demonstration methods of instruction. The subjects were classified on the Neilson-Cozens Classification Index and divided into three groups. The first group received the kinesthetic method of instruction, the second group was instructed using the demonstration method, and the third group did not receive any formal instruction. The data were examined by computing the mean and standard deviation of each pre-test and post-test group. The mean and standard deviation of the pre-test scores were 60.61 and 7.589. The mean and standard deviation of the post-test scores were 61.31 and 7.397. When each pre-test score was subtracted from its corresponding post-test score it was revealed that the demonstration group showed an increase in performance of eighteen boys, the kinesthetic group increased by sixteen boys and the group receiving no formal instruction increased by seven boys. Analysis of variance of matched groups revealed an F ratio of 2.68 which was not significant at the .05 level. An alternate approach was attempted in which the effect of the pre-test scores were partialled out from the post-test scores. Subjected to matched group analysis of variance design indicated an F ratio of 2.68 which was not significant at the .05 level. The resu1ts of a randomized group analysis without matching revealed an F ratio of 2.68 which was quite similar to the previous results and also insignificant at the .05 level. Randomized group analysis without matching between post-test scores and the regression equation indicated an F ratio of 2.72 which again was found insignificant at the .05 level of significance. It was found that no statistically significant difference could be obtained by use of one instructional technique exclusively in preference to another

Optimizing the temperature profile during sublimation growth of SiC single crystals: Control of heating power, frequency, and coil position

We use a numerical optimization method to determine the control parameters frequency, power, and coil position for the radio frequency (RF) induction heating of the growth apparatus during sublimation growth of SiC single crystals via physical vapo transport (PVT) (also called the modified Lely method). The control parameters are determined to minimize a functional, tuning the radial temperature gradient on the single crystal surface as well as the vertical temperature gradient between SiC source and seed, both being crucial for high-quality growth. The optimization is subject to constraints with respect to a required temperature difference between source and seed, a required temperature range at the seed, and an upper bound for the temperature in the entire apparatus. The numerical computations use a stationary mathematical model for the heat transport, including heat conduction, radiation, and RF heating to solve the forward problem, and a Nelder-Mead method for optimization. A minimal radial temperature gradient is found to coincide with a minimal temperature at the single crystal surface, and a maximal temperature gradient between source and seed is found to coincide with a low coil position