Plough-extrusion Forming for Making Micro-groove Heat Pipes on Hydrostatic Thrust Bearings of Heavy Machinery

The present paper focuses on the manufacturing of micro-groove heat pipes on hydrostatic thrust bearings of heavy machinery. Special multitooth tools were designed for plough-extrusion forming heat pipes on flat copper. Experimental results were conducted to determine whether the plough-extrusion forming could achieve better performance than traditional wire electrical discharge. Furthermore, the processing using multi-tooth tool with 10 mm length, 55 tooth number, 0.25 mm tooth depth and 0.22 tooth top width was found to achieve the best performance among the six optional tools. The 50 mm/min forming speed was determined to acquire the best surface quality of the microgroove structure. Through heat transfer testing, the theoretical model for a micro-groove heat pipe made by plough-extrusion forming was also verified.

Benefits of a Guided Motor-Mental Preperformance Routine on Learning the Basketball Free Throw

While past research has shown the benefits of preperformance routines (PPRs) on athletes’ performances, only a few studies have addressed PPR effects on novices’ learning or performance. This study investigated the effect of motor-mental PPR on learning the basketball free throw. We categorized 45 undergraduate male students into three 15-session training groups receiving (a) a five-step PPR based on Singer’s model, (b) a self-regulation PPR, and (c) no PPR, but only a basketball free throw performance (control group). One week later, we conducted retention and transfer testing. A repeated measures analysis of variance and two-way mixed design analysis of variance showed that, in the acquisition and test phases, the five-step PPR group performed better than the other two groups ( p < .001), and there was no significant difference between the self-regulation PPR and control groups. The results also showed that, in accordance with the specificity of practice hypothesis, participants’ performance decreased significantly on transfer testing when PPR was removed from the experimental groups. A well-guided motor-mental PPR was superior to a self-regulated PPR for novices learning this basketball skill, probably because it increased the participants’ concentration during acquisition and helped them learn it as part of a motor pattern.

Simulator-based training for learning resuscitative transesophageal echocardiography

ABSTRACTObjectivesTransesophageal echocardiography (TEE) is a relatively new resuscitation tool in the emergency department. Recent studies have demonstrated that it can impact diagnosis and management of critically ill patients. The objective of this study is to determine the effectiveness of a simulation-based curriculum for teaching emergency medicine residents a five-view TEE protocol.MethodsEmergency medicine residents with previous ultrasound experience were invited to attend a 1-hour TEE training session. The training consisted of a didactic lecture followed by guided practice on a simulator. Performance was measured prior to training, after the training session, and by a transfer test 1 to 2 weeks after training. The primary outcome was the percentage of successful image generation using a scoring tool by two blinded reviewers.ResultsTwenty-two residents completed the study. The percentage of successful views increased from 44.5% (SD 27.9) at baseline to 98.6% (SD 3.5) after training (p < 0.001), and was 86.8% (SD 12.1) on transfer testing (p < 0.001).ConclusionA brief simulation-based teaching session was effective for teaching emergency medicine residents a five-view resuscitative TEE protocol. Future studies are needed to determine optimal methods for long-term skill retention.

Conjugate Heat Transfer Scaling for Inconel 718

Over the last decade, conjugate heat transfer testing has been shown to be important because it replicates the sum of the hot gas path heat transfer coefficient, film cooling, film cooling heat transfer augmentation, bore cooling, conduction through the wall, internal cooling heat transfer coefficients, and the relative amounts of heat pick up in the cooling flow. Instead of measuring these boundary conditions in individual experiments, conjugate heat transfer testing measures the cumulative effect as well as each boundary condition’s effect on the others. Typically, matched Biot number heat transfer experiments are performed at near room temperature with a surrogate material; however, this study examines how the thermal conductivity of a nickel alloy sufficiently changes between room temperature and temperatures representative of turbine engines to allow matched Bi heat transfer tests using nickel at laboratory conditions. The ratio of the thermal conductivity of air to the thermal conductivity of Inconel 718 stays mostly constant between engine representative temperatures and room temperature. Over this range, the thermal conductivity of both air and Inconel 718 change ∼2.5X, and the change in thermal conductivity allows for conjugate heat transfer tests to match Reynolds number, Nusselt number, film effectiveness, Biot number, and Stanton number. Experimental results at two temperature conditions are shown confirming the theory. Finally, a method for scaling the thermal impact of dust accumulation at laboratory conditions to turbine conditions is proposed.