The Effects of Inlet Blockage and Electrical Driving Mode on the Performance of a Needle-Ring Ionic Wind Pump.

The thermal management of microelectronics is important because overheating can lead to various reliability issues. The most common thermal solution used in microelectronics is forced convection, which is usually initiated and sustained by an airflow generator, such as rotary fans. However, traditional rotary fans might not be appropriate for microelectronics due to the space limit. The form factor of an ionic wind pump can be small and, thus, could play a role in the thermal management of microelectronics. This paper presents how the performance of a needle-ring ionic wind pump responds to inlet blockage in different electrical driving modes (direct current), including the flow rate, the corona power, and the energy efficiency. The results show that the performance of small needle-ring ionic wind pumps is sensitive to neither the inlet blockage nor the electrical driving mode, making needle-ring ionic wind pumps a viable option for microelectronics. On the other hand, it is preferable to drive needle-ring ionic wind pumps by a constant current if consistent performance is desired.

Thoracic Endovascular Aortic Repair for Type B Aortic Dissection Associated with Retrograde Type A Intramural Hematoma.

PURPOSE: To evaluate feasibility and efficacy of thoracic endovascular aortic repair (TEVAR) for type B aortic dissection (TBAD) associated with retrograde type A intramural hematoma (IMH). MATERIALS AND METHODS: From April 2013 to January 2017, 15 consecutive patients with TBAD associated with retrograde type A IMH who underwent TEVAR were reviewed retrospectively. There was no cardiac tamponade, aortic regurgitation, involvement of coronary artery, or sign of cerebral ischemia in these patients. Enhanced CT was used in 4 patients to diagnose malperfusion of abdominal visceral arteries or lower extremity artery and underwent emergent TEVAR. For the remaining 11 patients, repeated enhanced CT after initial medical treatment within 24 hours from onset of pain showed expansion of IMH in 8 patients or presence of periaortic hematoma in 3 patients. Delayed TEVAR was scheduled for these cases. RESULTS: Successful deployment of the stent graft was achieved in all patients. There were no severe postoperative complications, such as retrograde type A aortic dissection or aortic rupture. Sudden death occurred in 1 patient 3 months after the procedure. Thrombosis of the false lumen, shrinkage of the diameter of the aorta, and complete absorption of the IMH were observed in the remaining patients at a mean follow-up of 19.8 months ± 6.57. CONCLUSIONS: TEVAR for treatment of TBAD with retrograde type A IMH is feasible and effective. It represents a treatment option for patients with TBAD associated with type A IMH with a proximal entry tear located in the descending aorta.

Hybrid Energy Harvester Consisting of Piezoelectric Fibers with Largely Enhanced 20 V for Wearable and Muscle-Driven Applications.

We present a polyvinylidene fluoride (PVDF) nanogenerator (NG) with advantages of direct writing and in situ poling via near-field electrospinning (NFES), which is completely location addressable and substrate independent. The maximum output voltage reached 20 V from the three layers piled NGs with serial connections, and the maximum output current can exceed 390 nA with the parallel integration setup. Linear superposition and switching polarity of current and voltage tests were validated by the authentic piezoelectric output. Nanofiber (NF)-based devices with a length ∼5 cm can be easily attached on the human finger under folding-releasing at ∼45°, and the output voltage and current can reach 0.8 V and 30 nA, respectively. This work based on NFs can potentially have a huge impact on harvesting various external sources from mechanical energies.