Carbon fiber reinforced polymer as epoxy, but other thermoset or thermoplastic polymers, such as polyester, vinyl ester, or nylon, are sometimes used. The composite material may contain aramid (e.g. Kevlar, Twaron), ultra-high-molecular-weight polyethylene (UHMWPE), aluminium, or glass fibers in addition to carbon fibers. The properties of the final CFRP product can also be affected by the type of additives introduced to the binding matrix (resin). The most common additive is silica, but other additives such as rubber and carbon nanotubes can be used. The material is also referred to as "graphite-reinforced polymer" or "graphite fiber-reinforced polymer" ("GFRP" is less common, as it clashes with
What Are They Doing in Heaven? in a wide variety of styles, including gospel and bluegrass; sometimes attributed to Phillips or to "anonymous" or to "traditional". What Are They Doing in Heaven? "What Are They Doing in Heaven?" is a Christian hymn written in 1901 by American Methodist minister Charles Albert Tindley. , it has become popular enough to have been included in 16 hymnals. The song has sometimes been recorded under the titles "What Are They Doing?" and "What Are They Doing in Heaven Today?". The question mark is often omitted. The song may also be known by its first line, "I am thinking of