Publisher Summary Thermal control of electronic components has one principal objective, to maintain relatively constant component temperature equal to or below the manufacturer's maximum specified service temperature, typically between 85 and 100°C. It is noted that even a single component operating 10°C beyond this temperature can reduce the reliability of certain systems by as much as 50%. Therefore, it is important for the new thermal control schemes to be capable of eliminating hot spots within the electronic devices, removing heat from these devices and dissipating this heat to the surrounding environment. Several strategies have developed over the years for controlling and removing the heat generated in multichip modules, which include advanced air-cooling schemes, direct cooling, and miniature thermosyphons or free-falling liquid films. The chapter summarizes analytical, numerical, and experimental work in literature, in order to facilitate the improvement of existing schemes and provide a basis for the development of new ones. The chapter focuses on investigations performed over the past decade and includes information on the thermal control of semiconductor devices, modules, and total systems.

Thermal Control of Electronic Equipment and Devices

An X-ray CT apparatus comprises: motion information acquisition means that acquires periodical motion information on a motion portion of an object to be examined; a detector that rotates together with an X-ray source and detects X-rays applied to the object from the X-ray source to acquire projection data per collection region; and reconstruction means that processes the projection data resulting from the detector to reconstruct a tomogram of the object, wherein the X-ray CT apparatus further includes delay time determination means that determines a delay time by adding a time width of the collection region and a processing delay time in the X-ray CT apparatus and a time interval from the moment when the phase of the measured periodical motion information is matched with the phase of the rotation period of the X-ray CT apparatus to the moment when they are matched next time, and collection means that correlates, with the periodical motion information obtained by the motion information acquisition means, and successively collects the projection data obtained from the detector, with the reconstruction means starting reconstruction of the tomogram after the delay time.

X-ray ct device

A system for restricting mixing of air in a data center includes a plurality of racks, each of the racks having a front face and a back face The system includes an enclosure for collecting air released from the back faces of the plurality of racks, the enclosure configured to substantially contain the air in an area between the first row and the second row and having a roof panel coupled to the first row of racks and the second row of racks configured to span a distance between the first row of racks and the second row of racks The enclosure is configured to maintain a first air pressure inside of the enclosure that is substantially equal to a second air pressure outside the enclosure

Data center cooling

An imaging apparatus and related method comprising a detector located a distance from a source and positioned to receive a beam of radiation in a trajectory; a detector positioner that translates the detector to an alternate position in a direction that is substantially normal to the trajectory; and a beam positioner that alters the trajectory of the radiation beam to direct the beam onto the detector located at the alternate position

Systems and methods for imaging large field-of-view objects

A modular door mounted heat exchanger (10) for use with an outdoor equipment enclosure (12) of the type having a sealed equipment compartment (22) used to house heat generating electronics and telecommunications equipment (29) therein is disclosed. The heat exchanger includes a door panel (33) sized and shaped to be received on, and to close an access opening (20) defined as a part of the equipment enclosure. The door panel has an interior surface (34) for facing inwardly of the enclosure, and an exterior surface (36) for facing outwardly of the enclosure. A heat exchanger cover (37) constructed and arranged to be mounted to the exterior surface of the door panel is provided. The heat exchanger cover defines a plenum (38) between the exterior surface of the door panel and the heat exchanger cover. At least a first opening (40) and at least a spaced second opening (41) are defined within the plenum for defining an air flow path (44, 45) passing within and at least partially along the plenum. At least one fan (42, 48, 79) is provided for drawing air into and exhausting air out of the plenum through the at least first and second openings, respectively. The fan is constructed and arranged to draw outside air through the plenum for cooling the exterior surface of the door panel, so that the air within the enclosure that comes into contact with the interior surface of the door panel is in turn cooled.

Door mounted heat exchanger for outdoor equipment enclosure

Thermal design is one of the most important issues in developing compact self-ballasted fluorescent lamps which are required to be in smaller size and with higher output. In this paper, a simulation model is proposed using thermal network equations. The thermal network equations are derived from the theoretical system consisting of thermal circuit which is analogous with an electric circuit. The coefficients of the thermal network equations can be obtained by a model experiment using a heater. The calculated temperatures are in good agreement with the measured temperatures. The thermal simulation is useful for designing compact self-ballasted fluorescent lamps.

/pdf/thermal-simulation-of-compact-self-ballasted-fluorescent-3pl970e0yy.pdf

Thermal Simulation of Compact Self-ballasted Fluorescent Lamps.

This paper presents a simple formula for thermal designing of natural-air-cooled electronic equipment casings with standard arrangement for circuit boards and power supplies. The formula meets the requirements as a practical formula, since it represents the air-cooling system in its simplified form with due regard to such factors as the stack effects, air Flow resistance, natural convective transfer and so on. The formula was applied to predict temperature rise for two practically used electronic equipment cabinets with standard arrangements and a modeling case. The predicted temperature rise values, obtained through the formula, caused very slight errors, with only 10 percent in the actual values based upon experiment results.

On the cooling of natural-air-cooled electronic equipment casings (Proposal of a practical formula for thermal design)

PURPOSE:To provide a title invention which can be manufactured easily free in shape, size, and array of the fin division. CONSTITUTION:A stacked body 14 is provided with a plurality of heatsink fin elements 12 stacked via spacers 13 spacing out them as predetermined: every element 12 has pin fins 17 constituted with a plurality of slits 16 cut in a thin plate 15 formed of a thermal conductor.

Heatsink, heatsink apparatus and manufacture of heatsink

This paper describes some experimental values of aerodynamic resistance of perforated plates in natural convection, providing basic thermal data necessary for designing electronic equipment casings. In the conventional measuring method which measures only in the higher region of Reynolds number, there is a disadvantage that the utmost precision cannot be attained in measurement due to the values of pressure loss and velocity being unidentifiably small. Io our new method, however, it is designed to evaluate a fluid resistance coefficient depending on the air temperature elevated by the combined effect of motive power of natural convection and fluid resistance and consequently to elucidate the influence of Reynolds number, coefficient of porosity, and thickness of plates/diameter of holes on resistance coefficient of perforated plates.

Aerodynamic Resistance of Perforated Plates in Natural Convection

On the purpose to examine a heat dissipation capability of fin in actual electoronic equipments, the effect of an obstacle above a fin on the cooling performances was experimentally investigated. The decrease of the distance from the obstacle affected natural air convection from the fin and reduced the heat transfer coefficient. The effect of the supply wattage, the fin temperature and the fin bight on the cooling Performances were also discussed.

Tomiya Sasaki

Papers

Thermal Simulation of Compact Self-ballasted Fluorescent Lamps.

On the cooling of natural-air-cooled electronic equipment casings (Proposal of a practical formula for thermal design)

Heatsink, heatsink apparatus and manufacture of heatsink

Aerodynamic Resistance of Perforated Plates in Natural Convection

Cooling performances for fins under an obstacle.