Effect of a semi electro-mechanical engine valve on performance and emissions in a single cylinder spark ignited engine

In this study, an electro-mechanical valve （EMV） system for the intake valve ofa fottr stroke, single cylinder, overhead valve and spark ignition （SI） engine was designed and constructed. An engine with the EMV system and a standard engine were tested to observe the effects of the EMV on engine performance and emissions at different speeds under full load. The EMV engine showed improved engine power, engine torque and break specific fuel consumption （BSFC）. A 66% decrease in CO emissions was also obtained with the EMV system, but hydrocarbons （HC） and NOx emissions increased by 12% and 13% respectively.     

REAL: Ein ressourcenadaptierendes mobiles Navigationssystem

Zusammenfassung.   Die intelligente Ressourcenadaption ist eine der gro?en Herausforderungen für die n?chste Generation mobiler Navigationssysteme. Da man typischerweise mehrere Fortbewegungsarten oder Verkehrsmittel kombinieren muss, um an einen Zielort zu gelangen, muss sichergestellt werden, dass mobile, allgegenw?rtige Navigationshilfen dies über eine jeweils situationsangepasste Benutzerschnittstelle unterstützen. Der notwendige Wechsel zwischen verschiedenen Positionierungstechnologien soll für den Endbenutzer m?glichst unbemerkt bleiben. Im folgenden wird ein hybrides Personennavigationssystem vorgestellt, das die in bestimmten Fortbewegungssituationen verfügbaren Positionierungstechnologien und deren Genauigkeit optimal nutzt, um die Pr?sentation der Wegbeschreibung auf verschiedene Endger?te und Ausgabemodalit?ten sowie die kognitive Ressourcenlage des Benutzers zu adaptieren. Eingegangen am 28. Februar 2001 / Angenommen am 8. August 2001     

Arms control for armed uninhabited vehicles: an ethical issue

Arming uninhabited vehicles (UVs) is an increasing trend. Widespread deployment can bring dangers for arms-control agreements and international humanitarian law (IHL). Armed UVs can destabilise the situation between potential opponents. Smaller systems can be used for terrorism. Using a systematic definition existing international regulation of armed UVs in the fields of arms control, export control and transparency measures is reviewed; these partly include armed UVs, but leave large gaps. For preventive arms control a general prohibition of armed UVs would be best. If that is unattainable, several measures should be taken. An explicit prohibition of autonomous attack, that is without a human decision, should be added to IHL. Concerning armed UVs remotely controlled by a human soldier, recommendations differ according to type or mission. New kinds of uninhabited nuclear-weapon carriers should be banned. Space weapons should be prohibited in general. UVs smaller than 0.2–0.5 m should be banned. Bigger remotely controlled armed UVs not equipped with weapons of mass destruction should be subject to numerical limitations in various categories. For these the Treaty on Conventional Armed Forces in Europe is an important precedent.     

Perceptual-cognitive expertise of handball coaches in their young and middle adult years

There is little research investigating the maintenance of perceptual-cognitive expertise in general and even less comparing coaches of different ages. The aim of this study was to test for perceptual-cognitive differences between age groups, licence levels, and their interaction. This study investigated differences in skilled performance between young and middle-aged coaches of three different skill levels. Participants performed an accuracy-oriented pattern recall (mean distance in pixel) and a time-oriented flicker test (mean detection time in ms). There were some significant differences between age groups and between skill groups for both tests, but no interactions. For the pattern recall test, the effect sizes were larger for skill level differences, while for the flicker test effects were larger for ageing. These results suggest coaches are able to maintain accuracy skills better than reaction timed tasks. This is in line with findings on speeded performance in general populations, which show declines with age. Moreover, results also support findings on perceptual expertise in skills where accuracy was important.     

Mediated Effects of Technology Competencies and Experiences on Relations among Attitudes Towards Technology Use,Technology Ownership,and Self Efficacy about Technological Pedagogical Content Knowledge

This study examined the relations of preservice science teachers’ attitudes towards technology use, technology ownership, technology competencies, and experiences to their self-efficacy beliefs about technological pedagogical content knowledge (TPACK). The present study also investigated interrelations among preservice teachers’ attitudes towards technology use, technology ownership, technology competencies, and experiences. The participants of study were 665 elementary preservice science teachers (467 females, 198 males) from 7 colleges in Turkey. The proposed model based on educational technology literature was tested using structural equation modeling. The model testing results revealed that preservice teachers’ technology competencies and experiences mediated the relation of technology ownership to their TPACK self efficacy beliefs. The direct relation of their possession of technology to their TPACK self efficacy beliefs was insignificant while the indirect relation through their technology competencies and experiences was significant. The results also indicated there were significant direct effects of preservice teachers’ attitudes towards technology use, technology competencies, and experiences on their TPACK self efficacy beliefs.     

Pre‐service primary education teachers’ changing attitudes towards teaching: a longitudinal study

This study investigated the longitudinal changes in the attitudes of pre‐service primary education teachers towards the teaching profession as they progressed through training. The results indicate that there is a significant difference in pre‐service teachers’ attitudes towards the profession between their freshman and senior years. Moreover, the findings obtained through interview data have shown that both positive and negative changes occur in pre‐service teachers’ attitudes towards teaching throughout their education, and these changes are observed to be related to teaching practice, cooperating teachers, teacher education institutions and teacher educators.     

Studieren an der Berufsakademie oder an der Universität, Fachhochschule oder Pädagogischen Hochschule?

Beim übergang von der Schule auf die Universit?t müssen sich Abiturienten u.a. für einen bestimmten Hochschultypus entscheiden. Der Fokus in diesem Beitrag liegt auf der sogenannten Berufsakademie, die in einigen Bundesl?ndern eine interessante, aber wenig beachtete Alternative zu Universit?t, Fachhochschule und P?dagogischer Hochschule darstellt. Anhand einer gro?en L?ngsschnittstudie, die in Baden-Württemberg durchgeführt wird, werden der Leistungsstand, der famili?re Hintergrund, die beruflichen Interessen und die Studienwahlmotive von (künftigen) Studierenden an den verschiedenen Hochschultypen untersucht. Berufsakademien erwiesen sich insbesondere für Abiturienten mit weniger günstigem famili?ren Hintergrund und dem Wunsch, rasch finanziell unabh?ngig zu sein, sowie für Absolventen beruflicher Gymnasien als attraktive Alternative zur Universit?t. Berücksichtigt man die schulische Herkunft (berufliches vs. allgemeinbildendes Gymnasium), so fanden sich ?hnliche kognitive Eingangsvoraussetzungen bei Studierenden wirtschaftswissenschaftlicher F?cher an Berufsakademie, Fachhochschule und Universit?t.