in this study, friction stir spot welding (fssw) is applied to join the tial6v4 titanium alloy with 1.5 mm thickness and then the effect of rotational speed and tool dwell time on microstructure and mechanical properties is investigated. in this regard, the speed of the tool rotation was considered as 800, 1000, and 1200 rpm, as well as the tool dwell time was set at 7 and 12s. microstructural ...

The abstraction of a hybrid system by eliminating one or more of its continuous variables is in general too coarse. In this situation, dwell time refinement may be useful. The idea is to impose explicit constraints on the time that may resp. must be spent (or “dwelled”) between successive mode switches. We show how the required constraints can be inferred automatically (with acceptable cost). T...

Microstructures, tensile properties and fracture energy of a friction stir spot welded polycarbonate (FSSW) were studied at varying rotational rates and dwelling time. The problem of common FSSW welding is the remaining of characteristic keyhole. This can act as a concentration place in mechanical tests. To order solve this problem authors took advantage of innovation for designing the welding ...

Introduction: The dwell time and transit time components contribute to the overall delivered dose to patients in high dose rate (HDR) brachytherapy treatments. The transit time results from source entry and exit as well as source movements between dwell positions. It depends on various parameters such as the source speed profile, source indexer distance to dwell position, and ...

Discrete-time switched linear systems where switchings are governed by a digraph are considered. The minimum (or average) dwell time that guarantees the asymptotic stability can be computed by calculating the maximum cycle ratio (or maximum cycle mean) of a doubly weighted digraph where weights depend on the eigenvalues and eigenvectors of subsystem matrices. The graph-based method is applied t...

Bus dwell time data collection typically involves labor-intensive ride checks. This paper reports an analysis of bus dwell times that use archived automatic vehicle location (AVL)/automatic passenger counter (APC) data reported at the level of individual bus stops. The archived data provide a large number of observations that serve to better understand the determinants of dwells, including anal...