Design, Simulation, and Fabrication of a Copper–Chrome-Based Glass Heater Integrated into a PMMA Microfluidic System

In this paper, the development of a copper–chrome-based glass microheater and its integration into a Polymethylmethacrylate (PMMA) microfluidic system are presented. The process highlights the importance of an appropriate characterization, taking advantage of computer-simulated physical methods in the heat transfer process. The presented system architecture allows the integration for the development of a thermal flow sensor, in which the fluid flows through a 1 mm width × 1 mm length microchannel across a 5 mm width × 13 mm length heating surface. Using an electrothermal analysis, based on a simulation and design process, the surface heating behavior curve was analyzed to choose a heating reference point, primarily used to control the temperature point within the fluidic microsystem. The heater was characterized using the theory of electrical instrumentation, with a 7.22% error for the heating characterization and a 5.42% error for the power consumption, measured at 0.69 W at a temperature of 70 °C. Further tests, at a temperature of 115 °C, were used to observe the effects of the heat transfer through convection on the fluid and the heater surface for different flow rates, which can be used for the development of thermal flowmeters using the configuration presented in this work.

Fatigue Performance Evaluation of AZ31B Magnesium Alloy Based on Statistical Analysis of Self-Heating

AZ31B magnesium alloy is the experimental material in this study. Considering its anisotropy, fatigue assessment based on self-heating is carried out for both the extrusion direction and the transverse direction. The self-heating behavior in the two orientations is compared. Similar to steels, an obvious inflection point that corresponds to the fatigue limit can be found in the self-heating vs. load curve for AZ31B. A new fatigue limit assessment method is proposed based on a statistical analysis of self-heating data. This method can provide a satisfactory assessment of the fatigue limit for AZ31B in the both orientations.

Effect of C:SiO2 Ratio on Heating Behavior and Photoluminescence Property of SiC by Microwave

Coal minerals and tetraethoxysilane were used to prepare SiC by microwave heating. Different C:SiO2 ratios of raw mixed powders were selected to investigate changes in the heating behavior and photoluminescence property. The prepared samples were characterized by X-ray diffraction (XRD) Raman Field-emission scanning electron microscopy (SEM) and X-ray fluorescence spectrophotometer. It was found that distinct heating behavior appeared for different C:SiO2 ratios, including the time taken to reach ~600 °C, performance of the thermal runaway, and heating rate. The changes in the complicated heating behaviors are determined by different microwave coupling, microwave plasma, and E-field intensification effects within samples with different C:SiO2 ratios. When the molar ration of carbon and silicon is 5:1, the intensity of light emission reaches maximum.