Consider the steadystate temperature distribution within a c

Consider the steady-state temperature distribution within a composite wall composed of Materials A and B. The conduction process is one-dimensional. Within which material does uniform volumetric generation occur? What is the boundary condition at x = -L_A? How would the temperature distribution change if the thermal conductivity of Material A were doubled? How would the temperature distribution change if the thermal conductivity of Material B were doubled? Sketch the heat flux distribution q_x\"(x) through the composite wall.

Solution

the Steady State theory is an alternative to the Big Bang model of the evolution of the universe. In the steady-state theory, the density of matter in the expanding universe remains unchanged due to a continuous creation of matter, thus adhering to the perfect cosmological principle, a principle that asserts that the observable universe is basically the same at any time as well as at any place.

While the steady state model enjoyed some popularity in the mid-20th century, it is now rejected by the vast majority of cosmologists, astrophysicists andastronomers, as the observational evidence points to a hot Big Bang cosmology with a finite age of the universe, which the Steady State model does not predict

Problems with the steady-state theory began to emerge in the 1950s and 60s, when observations began to support the idea that the universe was in fact changing: bright radio sources (quasars and radio galaxies) were found only at large distances (therefore could have existed only in the distant past), not in closer galaxies. Whereas the Big Bang theory predicted as much, the Steady State theory predicted that such objects would be found throughout the universe, including close to our own galaxy. By 1961, statistical tests based on radio-source surveys^[6] had ruled out the steady state model in the minds of most cosmologists, although some proponents of the steady state insisted that the radio data were suspec