Electric heating plate

A horizontal circular plate, J. 0 m in diameter, is to be maintained at 500 K by placing it 0.20 m directly beneath a horizontal electrically heated plate, also 1.0 m in diameter, maintained at 1000 K. The assembly is exposed to black surroundings at 300 K, and convection heat transfer is negligible. Estimate the electrical input to the heater and the net rate of heat transfer to the plate if the emissivity of the heater is 0.75 and the emissivity ol the plate 0.5. 

A 2-L beaker is placed on an electric heating plate, clamped to a rack, and equipped with a mechanical stirrer (rod and wing in stainless steel). This reaction mixture is placed in the beaker and allowed to cool to 100 °C. From a dropping funnel, en (lOOmL, 1.50mol) is added dropwise (3-6 mL min-1) with stirring. The heat of reaction will increase the temperature, which should... 

Apparatus for the study of TL is usually simple in its design and principles (see, e.g., (10)). The sample, prepared either as grains or a slice a fraction of a mm thick, is placed on an electrically heated plate in an inert gas and, as the temperature is raised, the light output is recorded using a photomultiplier. 

A sample holder usually a glass capillary tube sealed at one end in the case of the oil bath and heated block systems, or a pair of microscope slides on an electrically heated plate in the Kofler block. 

In the linear heat-flow method two disc-shaped specimens are placed on either side of an electrically-heated plate and the temperature profiles across the samples are monitored by thermocouples sited on both faces of the specimens. The apparatus is well insulated to minimise heat losses. In some versions of this method, the total heat flux passing through the samples is determined... 

If the plate Is not an electrical conductor or if electric current through the plate is undesirable, another electrically heated plate (guard heater), electrically insulated from but in good thermal contact with the original plate, can be utilized. 

Admission can also be thermally heated in accordance to a thermal sensor you can heat up inlet gas during cold starting by ensuring a heat transfer from the exhaust gases. Or create an electrically heated plate in order to compensate for the latent heat of vaporisation of the fuel. The cooling potential of this effect can be very significant about 30 K for gasoline but more than 200 K with methanol. 

Melt pressing is a first technique which results in thin polymer films. Polymer granules are heated between electrically heated plates, which can be forced against each other. Since this is a discontinuous process, it has little industrial application. However, if the mould plates are micro-structured, structured polymer sheets can be developed. In this case, the term hot-embossing is generally applied. 

Several attempts have been made for the determination of ignition temperature of solid plastics. Delmonte and Azam heated plastic specimens by molten NaOH while Hanel and Soder used an electric heating plate. 

The glowing temperature of the powder layer in open air is measured by an electric heating plate. The powder sample is distributed on a circular plate of 150 mm dia. at a thickness of 5 mm (Fig. 3.78). The minimum temperature of the metal plate at which the powder layer will glow up within 3 hours is determined. The glowing temperatures of some plastics powders are presented in Table 3.14... 

The mass of high-quality molten glass is then drawn through the holes of a platinum plate and bushed into fibers of the desired diameter. The electrically heated plate has a varying number of nozzles, ranging from 200 to 4,000. Immediately underneath the plate, filaments are covered with a coat or an organic coating. 

Electric Heating Plate, Immersion Heater and Heating... 

Heaters and ultrasonic baths are mainly used to increase dissolution of substances. The most generally used heaters are the gas stove and gas burner, electric heating plate,... 

Croup A carried out experiments with an electrically heated plate (length L in direction of flow=1 m, area A = 0.5m ) cooled by forced air with a velocity of 10 to 30m s The plate has a very high heat conductivity and thus a uniform temperature. A constant temperature differrence between the plate (with temperature 302 K) and the main stream of air of 2 K is established by adjusting the electrical power. The heating power is then measured as a function of the gas velocity (Figure 3.2.5). 

Heated tool welding can in practice be more complex than the other forms of heat sealing already described. Its most simple form is an electrically heated plate or knife with polished surfaces. The parts to be bonded are held against the polished surfaces, thus conducting the heat to the interfaces of the plastics components, which become plasticised, after which they are held together under pressure until cool. The temperature requirements vary from about 180°C to 230°C. 

Determination of the heat meter calibration constant was made using standard samples whose conductivity at higher temperatures was accurately known from guarded hot-plate measurements. For calibration an electrically heated plate was used instead of the cold plate thus the heat meter temperature was maintained near ambient at all times. 

Fernandez et al. [31] have synthesized zeolites by reflux heating of stirred mixture of fly ash and 2.5 M NaOH and/or KOH solution, on an electrically heated plate at 100 °C for 24 or 48 h by maintaining solution to fly ash ratio (L/S) as 0.005 L/g. The potential reuse of waste alkaline solution has been evaluated for activation of a fresh fly ash sample. It has been observed that there is no change in the CEC value of zeolitic product obtained, which is an anomaly and should be researched further. It has also been reported that the zeolitic yield has been up to 38 % (viz., Na-Pl and Analcime) and 34 % (viz., Chabazite) for NaOH and KOH activations, respectively. The mineral phase transition has been attributed to the activation of majority of amorphous glass with NaOH, whereas MuUite and Quartz can get dissolved under strong alkaline conditions. It has been demonstrated that the products obtained after NaOH activation can get contaminated with more leachates and trace elements like Cd and As, as compared to KOH activation from fly ash. 

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