Employment of 3D-Printed Bilayer Structures with Embedded Continuous Fibers for Thermal Management Applications: An Axial Cooling 4D-Printed Fan Application Case Study.

Bi-material composite structures with continuous fibers embedded on polymer substrates exhibit self-morphing under thermal stimulus induced by the different coefficients of thermal expansion (CTE) between the two constituent materials. In this study, a series of such structures are investigated in terms of fiber patterns and materials to achieve programmable and reversible transformations that can be exploited for thermal management applications. Stemming from this investigation's results, an axial cooling fan prototype is designed and fabricated with composite blades that passively alter their shape, specifically their curvature and twist angle, under different operating temperatures.

3D Printing Processability of a Thermally Conductive Compound Based on Carbon Nanofiller-Modified Thermoplastic Polyamide 12.

A polyamide (PA) 12-based thermoplastic composite was modified with carbon nanotubes (CNTs), CNTs grafted onto chopped carbon fibers (CFs), and graphene nanoplatelets (GNPs) with CNTs to improve its thermal conductivity for application as a heat sink in electronic components. The carbon-based nanofillers were examined by SEM and Raman. The laser flash method was used to measure the thermal diffusivity in order to calculate the thermal conductivity.

Treatment of unstable lower cervical spine injuries by anterior instrumented fusion alone.

Study Design: Retrospective study of a prospectively followed cohort.

Objective: To summarize the complications after instrumented stabilization of cervical spine injuries in a single-institution series, and to discuss management of unstable injuries with respect to the complication rate between the 2 approaches (anterior and posterior).

Summary Of Background Data: The anterior approach to the cervical spine has been criticized for destruction of the anterior elements in the presence of posterior instability.

Current Concepts: Aseptic Nonunion of Femoral Shaft Diaphysis.

In spite of increased understanding of biomechanics and improvements of implant design, nonunion of femoral shaft fractures continues to hinder the treatment of these injuries. Femoral nonunion presents a difficult treatment challenge for the surgeon and a formidable personal and economic hardship for the patient. In most series of femoral fractures treated with intramedullary nailing techniques, the incidence of this complication is estimated to be 1%.

Functional outcome of surgical treatment for multilevel lumbar spinal stenosis.

Background: There is no consensus regarding the best treatment of patients with multilevel lumbar stenosis. We evaluated the clinical and radiological findings in 41 patients with complex degenerative spinal stenosis of the lumbar spine who were treated surgically.

Methods: Between 1997 and 2003, 41 patients suffering from degenerative lumbar spinal stenosis were included in a prospective clinical study.