The Effects of Channel Curvature and Protusion Height on Nucleate Boiling and the Critical Heat Flux of a Simulated Electronic Chip

The quest for higher power yet smaller electronics has given rise to the need for very effective cooling of these electronics. Because one of the foremost problems in electronics cooling is achieving high heat flux cooling within small packages while expending minimal pumping power, one focus of this study was to investigate the effects of channel curvature on the CHF. Experimental data were obtained for flow rates of 1-7 m/s, subcoolings of 5-35 C, and radii of curvature of 25.4 and 50.8 mm. A correlation was obtained for these data which provided an excellent fit. One condition that has been ignored in the literature is the effect of the simulated heat source not being flush with the flow channel wall. In manufacturing an electronics cooling device, it will be very difficult to maintain the flush chip condition because of the dissimilar materials involved and the numerous thermal cyclings that the device will go through. Experiments showed a significant effect on CHF of the simulated heat source not being flush. A series of data was obtained for flow velocities of 1-4 m/s and subcoolings of 20-35°C. CHF data were obtained for a surface recessed 0.127 mnu, a flush surface, and surfaces protruded 0.229, 0.457, and 0.635 mm into the flow stream

Reconnaissance surveying of Bechevin Bay, AK using satellite-derived bathymetry

Recently, a remote sensing study has been conducted over Bechevin Bay Channel, Alaska as part of a collaboration project between NOAA and the U.S. Coast Guard (USCG). The goal of the study to develop a procedure to prioritize survey areas and plan the annual deployment of Aids to Navigation (AtoN) along the channel. Bechevin Bay is considered a priority for marine surveying because it constitutes the easternmost passage through the Aleutians from the Bering Sea to the Gulf of Alaska. The channel is located in a mud flat area, where every winter the passage is closed due to ice cover. As a result, the path of the channel may change after sea ice has melted. Because of the geographic location of Bechevin Bay, many resources are required in order to conduct an annual survey to map the channel’s path. The surveys are typically conducted by the USCG buoy tenders using small boats and reconnaissance-style single beam lines. This paper presents the use of single-image satellite-derived bathymetry (SDB) as an economic alternative approach. The study compares the performance using different band ratios. Datasets that were used in the study included Landsat 8 and WorldView 2 (WV-2) imagery

High Heat Flux Cooling for Spacecraft Electronics

An experimental investigation of flow boiling in a curved channel has been performed to ascertain its value in electronics cooling applications. Results have been obtained for flow velocities of 1 to 5 m/s and subcooling of 0.5 to 40 K. These results were compared to those of straight channel under identical velocity and subcooling conditions. The critical heat flux of the curved channel was found to be greater than that of the straight channel. In some cases the increase was found to be marginal, however. An unexplained temperature shift in the nucleate boiling regime was experienced during some experiments. Because this shift only occurred for the first test of the day, it is thought to be related to the incipience phenomenon often experienced in pool boiling experiments. Finally, true incipience overshoot and nucleate boiling regime hysteresis were found to be negligible

Comrade, Rest!

https://digitalcommons.library.umaine.edu/mmb-vp/5506/thumbnail.jp

3-Dimensional Scanning to Determine Body Volume and Composition With and Without a Wetsuit

Wetsuits are designed to improve swimming performance by providing increased buoyant forces, reduced drag forces, and compressive forces on the body. Recently, 3-D scanning technology (2015 Structure Scanner, Occipital) has been used to measure body volume, and may provide an alternative method to obtaining body composition. Purpose: Therefore, the purpose of this study is to use 3-D scanning to measure and compare body volume with and without a wet suit. Combined with mass, volume from 3-D scanning will provide density calculations for body composition analysis. A secondary purpose of this study is to measure the difference in body composition with and without a wetsuit. Methods: The Institutional Review Board has recently approved the study and data collection has started; therefore, no data are presented in this abstract. Participants will be 3-D scanned with and without a wetsuit (Company), followed by BodPod (COSMED) measurements with and without the wetsuit. Following measurements, the 3-D scan will be used to calculate volume using MeshLab Software (Company). 2x2 mixed-factor ANOVA will be run to analyze the differences between wetsuit conditions, and between measurement methods (3D Scan vs BodPod). By comparing measurements of body volume and calculations of body composition with and without a wetsuit, the validity of the 3-D scanning technique will be determined and this might lead to the development of empirically determined wetsuit fit criteria