Explain why the boss is concerned for the materials

Assignment Help Civil Engineering

Reference no: EM13319191

A young engineer is asked to design a thermal protection barrierfor a sensitive electronic device that might be exposed toirradiation from a high-powered infared laser. Having learned as astudent that a low thermal conductivity material provides goodinsulating characteristics, the engineer specifies use of ananostrutured aerogel, characterized by a thermal conductivity ofKa = 0.005 W/m-K, for the protective barrier. The engineer'sboss questions the wisdom of selecting the aerogel because it has alow thermal conductivity. Consider the sudden laserirradiation of (a) pure aluminum, (b) glass, and (c) aerogel. The laser provides irradiation of G = 10x10^6 W/m^2. The absortivities of the materials are alpha = 0.2, 0.9, and 0.8 for the aluminum, glass, andaerogel, respectively, and the initial temperature of the barrieris Ti = 300 K. Explain why the boss is concerned. Hint:All materials experience thermal expansion (or contraction), andlocal stresses that develop within a material are, to a first approximation, proportional to the local temperature gradient.

Kglass = 1.4 W/m-K
Kaluminum = 237 W/m-K

Reference no: EM13319191

Questions Cloud

An economy is faced by exhaustion of an important natural : An economy is faced by exhaustion of an important natural resource at a time when it is introducing improved technology.explain how these events will effect the economy production possibility curve.

What is the maximum distance away for the navigation lights : An offshore drilling rig is being towed out to sea. What is the maximum distance away that the navigation lights can still be seen by an observer standing at the shoreline

Explain the oxidation number of the monoatomic ions : What is the oxidation number of the monoatomic ions of the following elements. Sr,Rb, Na, Al,O,Se, Ba,I, Fr, Cl, N

The borrowers gain and lenders lose : 1) when inflation rises quickly, borrowers will be hurt or lenders if the actual inflation rate is less than the expected inflation then:

Explain why the boss is concerned for the materials : A young engineer is asked to design a thermal protection barrierfor a sensitive electronic device that might be exposed toirradiation from a high-powered infared laser.

Estimate the overall resistance of the fish : Suppose an electric eel touches the head and tail of a long, approximately cylindrically shaped fish and applies a voltage of 600V across it. estimate the overall resistance of the fish

What is the upward acceleration of the block : Imagine holding the above plastic block under water. When released, what is the upward acceleration of the block

How does analysis of demand contribute to business decision : How does analysis of demand contribute to business decision making give your answer with reference to the responsibilities of a sales manager?

Explain substance oxidized and the substance being reduced : For each reaction, identify the substance being oxidized and the substance being reduced. Express answers as chemical formulas for oxidized and reduced answers. 1. 2Sr(s)+O2(g)----->2SrO(s) 2. Ca(s)+Cl2(g)---->CaCl2(s) 3. Ni^2+(aq)+Mg^2+(aq)+Ni(s)

User Account

All Pages