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This work presents a novel rotary (EDM) electrical-discharge machining cutting process for a hard-to-machine cylindrical workpiece. An experimental analysis was carried out on an AISI D2 tool steel with a copper electrode. The effects of machining parameters such as pulsed current, pulse on-time, and workpiece rotation on material removal rate and surface roughness were analyzed. These effects were compared with those of conventional EDM without workpiece rotation. Experimental results indicated that the rotation enhanced the dielectric flow, thus effectively helping flush the debris from the gap between the electrodes. In addition, the material removal rate (MRR) increased with the rotation speed of the workpiece, whereas conventional EDM delivers only half the MRR. Surface roughness improves with increased rotation speed, a phenomenon that is attributed to the reduced recast layer during EDM.

Energy saving and carbon-emissions reduction (ESCER) are widely regarded as important issues for progress towards ensuring sustainable forms of economic development. This Taiwanese study focuses on the effects of a series of educational activities about ESCER on students' knowledge, attitudes and behavior. Sixty fifth-grade students from two elementary school classes were assigned to an experimental group, and 59 from two others to the control. Covariance and qualitative data analysis were conducted after 14 lessons on the topic in both 'treatments.' The following key findings emerged. First, hands-on 'energysaving house' learning activities seemed to have positive effects on students' knowledge, attitudes, and behavior toward ESCER, even as the design of authentic learning activities was recognized as not being as closely aligned to the students' daily lives as they could have been for achieving behavior-related outcomes. Second, students demonstrated slight gains in conceptual knowledge and procedural knowledge via the hands-on activities, but some ESCER misconceptions persisted. We conclude that students' learning processes, prior learning and authentic contexts for ESCER-related work should not be ignored in the attempt to link knowledge to action in teaching and learning activities.

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