Aluminum-26 heat source

In normal atmospheric conditions, fire usually is initialed by a combustible material coming in contact with a heat source. The spread of fire occurs due to direct flame impingement or the transfer of heat to the surrounding combustible materials. Heat transfer occurs by three principal mechanisms - conduction, convection, and radiation. Conduction is the movement of heat through a stationary medium, such as solids, liquids or gases. Steel is a good conductor of heat as is aluminum, therefore they can pass the heat of a fire if left unprotected. 

An ordinary 1000-watt lamp was used for heating as well as irradiation. The light reduces the induction period and accelerates the reaction. It is important that the solution be at reflux during the irradiation an aluminum foil tent may be used to prevent excessive loss of energy from the light/heat source. 

Aluminum electrodes were applied to all wafers by evaporation from an induction heated source, and patterned as shown in Figure 1. 

Fig. 9. Plate heat exchangers (a) plate—frame heat exchanger when hot fluid from the heat source enters the heat exchanger through connections in the stationary frame plate and is channeled over one side of each plate. Cold fluid enters through different frame plate connections and flows on the other side of each plate in a direction opposite to the hot fluid direction. Courtesy of Bell Gosset. (b) Limco model 6502 plate—fin heat exchanger having compact plate—fin aluminum brazed liquid-to-aii construction. The brazed plate—fin construction provides the most efficient heat-exchanger system in terms of size,...

For the fluorometric method, uranium is concentrated by co-precipitation with aluminum phosphate, dissolved in diluted nitric acid containing magnesium nitrate as a salting agent, and the co-precipitated uranium is extracted into ethyl acetate and dried. The uranium is dissolved in nitric acid, sodium fluoride flux is added, and the samples fused over a heat source (EPA 1980). 

More controversial (although sometimes cited as proven fact) have been claims (e.g., Taylor and Jakes, 1974 Taylor, 1982) that the bulk Moon is enriched roughly twofold in the cosmochemically refractory lithophile elements (a class that includes the REEs, the heat sources thorium and uranium, and the major elements aluminum, calcium, and titanium), and that compared to Earth s primitive mantle, the Moon s silicate mg ratio is much lower, i.e., its EeO concentration is much higher. Neither of these claims has been confirmed by recent lunar science developments, which include the advent of global thorium and samarium maps (Lawrence et al., 2002a Prettyman et al., 2002), data from lunar meteorites, and some radically changed interpretations of the Apollo seismic database. 

The cooling module, shown in Fig. 22, consists of an aluminum box with internal dimensions of 50 X 50 X 65 mm and wall thickness of 3.175 mm. At the bottom, the box is closed with a 3.175 mm thick stainless steel plate. The orifice plate was installed on a support located above the heat source and could be moved up or down. The heat source consists of a diode used in current controlled mode to avoid high voltages. The diode is mounted on a Direct Bond Copper (DBC) substrate layer, which is in turn glued on top of a GIO insulating base. The diode is 8.68 x 4.97 mm in size. The electrical connections are provided by means of two copper rods, 3.175 mm in diameter. 

Phenyldichlorophosphine (2) is prepared by gradually heating a mixture of benzene, phosphorus trichloride, and aluminum chloride until a yellow solution of the complex (1) results (2 hrs.) and then refluxing for 1 hr. The heat source is... 

Ultraminiaturized fiber optic sensors under 100 fim have only recently been fabricated. Tan et al [23, 24] developed a submicrometer optical fiber tip by pulling out silica fibers on a micropipette puller using a 25 W CO2 infrared laser as a heat source. Tips as small as 0.1 /xm could be reliably fabricated. After pulling, the tips were sputtered with aluminum in a vacuum chamber. This fabrication technique leaves a very small aperture at the tip, which can then be used as a near-field optical device (discussed in the next section). 

Iradiations above room temperature are carried out by pressing the powder into a 6 X 1 mm. slot milled in a 5 mm. diameter aluminum rod. The rod replaces the normal bit in a 25W soldering iron which acts as a heat source. The assembly is mounted vertically with a thermocouple fixed in the sample holder. Temperatures can be controlled to within 5°C. by regulating the current through the heating element with a Variac transformer. 

Fig, 10.4 Typical predicted global three-dimensional temperature field for moving friction stir welding (FSW) heat source, including heat transfer to backing plate. Source Ref 28. (b) Measured and predicted thermal cycles for a typical FSW in aluminum alloy 7075, using a finite volume solver for the numerical analysis. Source Ref 29... 

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