A mechanical model for the emplacement pipe system is developed. The model is then employed to determine the force applied to the surface collar of the emplacement pipe, the pipe-stemming load, and the stress along the emplacement pipe as a function of stemming height. These results are presented as integrals and a method for their numerical integration is given.

A retrofit solar water-heating system has been operating for the past two years in a three-story apartment building at Drexel University. The system employs two conventional collector banks (9 PPG collectors) mounted at the latitude angle for Philadelphia of 40 deg from the horizontal and two double-exposure collectors (DEC's) mounted vertically in mirrored enclosures. The relative performance of the conventional and double-exposure collectors has been monitored with an instrumentation system which was developed and installed in the basement of the apartment building. The DEC units have been found to provide from two to four times as much useful heat output per panel area than the PPG collectors. The higher relative performance values occur on clear winter days whereas lower relative performance values are found on clear summer days and generally overcast days. A cost analysis for a DEC unit relative to a conventional collector has also been performed. In the Philadelphia area the DEC units with their mirror enclosures would cost approximately 1.7 times as much per panel area as conventional collectors. Since the DEC units provide two to four times as much useful heat output, they are a cost-effective choice for flat or gently sloping roofs for which they …

The inertia and friction-welding processes were evaluated for joining aluminum alloy 1100-H14 and Type 316 vacuum-induction melted, vacuum-arc remelted (VIM VAR) stainless steel. While both processes consistently produced joints in which the strength exceeded the strength of the aluminum base metal, 100 percent bonding was not reliably achieved with inertia welding. The deficiency points out the need for development of nondestructive testing techniques for this type of joint. Additionally, solid-state volume diffusion did not appear to be a satisfactory explanation for the inertia and friction-welding bonding mechanism.