In laser back-scribing, a substrate is heated and melted by radiation absorption. Upon…

In laser back-scribing, a substrate is heated and melted by radiation absorption. Upon solidification, a volume change marks the region and this is used for recording. An example is given in Figure Pr. 3.64, where irradiation is provided through a thick glass layer and arrives from the backside to a thin layer of alumina. The … Continue reading "In laser back-scribing, a substrate is heated and melted by radiation absorption. Upon…"

In applications such as surface friction heat generation during automobile braking, the energy…

In applications such as surface friction heat generation during automobile braking, the energy conversion rate S˙ m,F decreases with time. For the automobile brake, this is modeled as For a semi-infinite solid initially at T (t = 0), when its surface at x = 0 experiences such time-dependent surface energy conversion, the surface temperature is … Continue reading "In applications such as surface friction heat generation during automobile braking, the energy…"

Water is heated (and assumed to have a uniform temperature, due to thermobuoyant motion mixing)…

Water is heated (and assumed to have a uniform temperature, due to thermobuoyant motion mixing) from T1(t = 0) to T1(t = tf ) = Tf by Joule heating in a cylindrical, portable water heater with inside radius R1 and height l, as shown in Figure Pr. 3.67. The ambient air temperature T2 is rather … Continue reading "Water is heated (and assumed to have a uniform temperature, due to thermobuoyant motion mixing)…"

A thin, flexible thermofoil (etched foil) heater with a mica (a cleavable mineral) casing is used…

A thin, flexible thermofoil (etched foil) heater with a mica (a cleavable mineral) casing is used to heat a copper block. This is shown in Figure Pr. 3.69. At the surface between the heater and the copper block, there is a contact resistance (Rk,c)1-2. Assume that the heater and the copper block both have small … Continue reading "A thin, flexible thermofoil (etched foil) heater with a mica (a cleavable mineral) casing is used…"

An initially cold T 1 (t = 0), pure aluminum spherical particle is rolling over a hot surface of…

An initially cold T1(t = 0), pure aluminum spherical particle is rolling over a hot surface of temperature Ts at a constant speed ub and is heated through a contact conduction resistance Rk,c. This is shown in Figure Pr. 3.70. (a) Draw the thermal circuit diagram. (b) Is the assumption of a uniform temperature valid? … Continue reading "An initially cold T 1 (t = 0), pure aluminum spherical particle is rolling over a hot surface of…"

In printed-circuit field-effect transistors, shown in Figure Pr. 3.71, the electrons are…

In printed-circuit field-effect transistors, shown in Figure Pr. 3.71, the electrons are periodically accelerated in the active layer and these electrons are scattered by collision with the lattice molecules (which is represented as collision with the lattice phonons), as well as collision with the other electrons and with impurities. These collisions result in the loss … Continue reading "In printed-circuit field-effect transistors, shown in Figure Pr. 3.71, the electrons are…"

A piece of polished iron, with a surface area A r = 1 m2, is heated to a temperature Ts =…

A piece of polished iron, with a surface area Ar = 1 m2, is heated to a temperature Ts = 1,100◦ C. (a) Determine the maximum amount of thermal radiation this surface can emit. (b) Determine the actual amount of thermal radiation this surface emits. Interpolate the total emissivity from the values listed in Table … Continue reading "A piece of polished iron, with a surface area A r = 1 m2, is heated to a temperature Ts =…"

A blackbody radiation source at Ti = 500◦C is used to irradiate three different surfaces,…

A blackbody radiation source at Ti = 500◦C is used to irradiate three different surfaces, namely, (i) aluminum (commercial sheet), (ii) nickel oxide, and (iii) paper. The irradiating surfaces have an area Ar = 1 m2 and are assumed gray, diffuse, and opaque. Use the emissivities in Table C.18 [for (ii) extrapolate; for others use … Continue reading "A blackbody radiation source at Ti = 500◦C is used to irradiate three different surfaces,…"