ABSTRACT
Detection and control of flow separation is a key to improving the efficiency of fluid machinery. In this study, we developed a flexible MEMS (microelectromechanical systems) sensor for measuring the wall shear stress and flow angle in subsonic airflow. The developed sensor is made of a flexible polyimide film and a microheater surrounded by three temperature sensor pairs. The sensor measures the wall shear stress from the heater output and the flow angle from the temperature gradient around the heater. The geometry and design of the heater and temperature sensors were determined based on numerical simulations. To evaluate the validity of the sensor, we conducted an experiment to measure the wall shear stress and the flow angle in a wind tunnel in different velocities ranging from 30 m/s to 170 m/s, equivalent to Mach numbers from 0.1 to 0.5. The heater output was proportional to one-third power of the wall shear stress. Additionally, the bridge output correlating the temperature difference between two opposing temperature sensors showed sinusoidal variation depending on the flow angle. Consequently, we have clarified that the developed sensor can measure both the wall shear stress and flow direction in subsonic flow.
ABSTRACT
Cellular homeostasis in response to glucose availability is maintained through the tight coordination of various physiological processes, including cell proliferation, transcription, and metabolism. In this study, we use the budding yeast Saccharomyces cerevisiae to identify proteins implicated in carbon source-dependent modulation of physiological processes. We find that the mitotic cyclin Clb4 is required for optimal regulation of glucose-starvation-responsive pathways through the target of rapamycin complex 1. Cells lacking Clb4 are characterized by dysregulation of autophagy and impaired modulation of cell size. Notably, cell viability after prolonged glucose starvation is severely reduced by disruption of Clb4. We conclude that Clb4, in addition to its function in the cell cycle, plays a role in the intracellular adaptation to glucose starvation.
