University of Paderborn

About: University of Paderborn is a education organization based out in Paderborn, Nordrhein-Westfalen, Germany. It is known for research contribution in the topics: Control reconfiguration & Software. The organization has 6684 authors who have published 16929 publications receiving 323154 citations.

Sliding friction in the presence of ultrasonic oscillations: superposition of longitudinal oscillations

Abstract: It was often observed that friction forces can be reduced significantly if ultrasonic oscillations are superposed to the macroscopic sliding velocity. This phenomenon can be used to improve machining processes by addition of ultrasonic vibration to tools or workpieces, and forms the basis for many processes of ultrasonic machining. On the other hand, ultrasonic vibrations can be used to generate motion. The thrusting force of ultrasonic motors is provided to the rotor through friction. In the present paper, a simple theoretical model for friction in the presence of ultrasonic oscillations is derived theoretically and validated experimentally. The model is capable of predicting the reduction of the macroscopic friction force as a function of the ultrasonic vibration frequency and amplitude and the macroscopic sliding velocity.

Corporate entrepreneurship and performance: A meta-analysis

Abstract: Despite considerable research, empirical findings on the relationship between corporate entrepreneurship (CE) (i.e., strategic renewal, innovation and corporate venturing) and performance remain inconclusive. Using a meta-analysis, the present paper synthesizes prior literature regarding the CE–performance relationship of 43 independent samples including 13,237 firms. Our results reveal that strategic renewal, innovation and corporate venturing positively influence overall, subjective and objective firm performance. In addition, we conduct moderator analyses to reflect on the context and to verify whether and how the relationships vary in the presence of several study-specific factors. We find that innovation has a stronger effect on performance in high-tech as opposed to low-tech industries, and the association between corporate venturing and performance is the strongest in Europe (compared with North America and Asia). Against our theoretical predictions, we find the association between strategic renewal and performance to be stronger for larger than for smaller firms. Based on our results, we derive recommendations for future research and point to managerial implications.