Miniature loop heat pipe with flat evaporator for cooling computer CPU

This paper presents an experimental investigation on a copper miniature loop heat pipe (mLHP) with a flat disk shaped evaporator, 30mm in diameter and 10-mm thick, designed for thermal control of computer microprocessors. Tests were conducted with water as the heat transfer fluid. The device was capable of transferring a heat load of 70W through a distance up to 150mm using 2-mm diameter transport lines. For a range of power applied to the evaporator, the system demonstrated very reliable startup and was able to achieve steady state without any symptoms of wick dry-out. Unlike cylindrical evaporators, flat evaporators are easy to attach to the heat source without need of any cylinder-to-plane reducer material at the interface and thus offer very low thermal resistance to the heat acquisition process. In the horizontal configuration, under air cooling, the minimum value for the mLHP thermal resistance is 0.17degC/W with the corresponding evaporator thermal resistance of 0.06degC/W. It is concluded from the outcomes of the current study that a mLHP with flat evaporator geometry can be effectively used for the thermal control of electronic equipment including notebooks with limited space and high heat flux chipsets. The results also confirm the superior heat transfer characteristics of the copper-water configuration in mLHP

Advanced Propulsion for Geostationary Orbit Insertion and North-South Station Keeping

Solar electric propulsion technology is currently being used for geostationary satellite station keeping. Analyses show that electric propulsion technologies can be used to obtain additional increases in payload mass by using them to perform part of the orbit transfer. Three electric propulsion technologies are examined at two power levels for geostationary insertion of an Atlas IIAS class spacecraft. The onboard chemical propulsion apogee engine fuel is reduced in this analysis to allow the use of electric propulsion. A numerical optimizer is used to determine the chemical burns that will minimize the electric propulsion transfer times. For a 1550-kg Atlas IIAS class payload, increases in net mass (geostationary satellite mass less wet propulsion system mass) of 150-800 kg are enabled by using electric propulsion for station keeping, advanced chemical engines for part of the transfer, and electric propulsion for the remainder of the transfer. Trip times are between one and four months

Advanced Propulsion for Geostationary Orbit Insertion and North-South Station Keeping

Solar electric propulsion (SEP) technology is currently being used for geostationary satellite station keeping to increase payload mass. Analyses show that advanced electric propulsion technologies can be used to obtain additional increases in payload mass by using these same technologies to perform part of the orbit transfer. In this work three electric propulsion technologies are examined at two power levels for an Atlas 2AS class spacecraft. The on-board chemical propulsion apogee engine fuel is reduced to allow the use of electric propulsion. A numerical optimizer is used to determine the chemical burns which will minimize the electric propulsion transfer time. Results show that for a 1550 kg Atlas 2AS class payload, increases in net mass (geostationary satellite mass less wet propulsion system mass) of 150 to 800 kg are possible using electric propulsion for station keeping, advanced chemical engines for part of the transfer, and electric propulsion for the remainder of the transfer. Trip times are between one and four months

Precipitation data and analysis

CER70-71DBS-EJR-MAS-JHD-VCD-HR50.May 1971.VIMHEX is an intensive program of tropical meteorological and hydrological observations taken in northeast Venezuela during the summer of 1969 to support a study of tropical atmospheric physics and the resulting effects of rainfall. The objectives of the program are to express the meso-scale weather structure in terms of the synoptic-scale envelope and to formulate the ground response to the rainfall produced by tropical weather disturbances over relatively flat tropical topography. The Volume I Hydrology Report lists all the precipitation data collected during the summer of 1969 in the study area of northeast Venezuela. Most of the precipitation data is in the form of hourly rainfall. In addition, weekly and other longer period isohyetal maps are presented for the study area. The weekly and monthly average precipitations over the drainage basins have been determined. For the summer months of July, August, and September an average of 4.8 mm of precipitation per day fell on the drainage basins. In subsequent reports, these data will be related to the hydrology and stream response of the area.VIMHEX was sponsored by the Department of Defense through its THEMIS program

Marine lebensspuren: improving the classification of seafloor traces from underwater imagery and observations

Project PID2019-104625RB-100 funded by MCIN/AEI/10.13039/50110001103

Magnetic Resonance

Contains research objectives and reports on three research projects

Multi-model Database Management Systems - A Look Forward

Peer reviewe