R-Values. An insulating materialâs resistance to conductive heat flow is measured or rated in terms of its thermal resistance or R-value -- the higher the R-value, the greater the insulating effectiveness. The R-value depends on the type of insulation, its thickness, and its density.he effectiveness of an insulation materialâs resistance to heat flow also depends on how and where the insulation is installed. For example, insulation that is compressed will not provide its full rated R-value.
So for me, âtarry scantâ simply means to âmove on quicklyâ. But to others it has meant different things. This is particularly true when Tarry is used as an adjective. In this case it is pronounced differently and comes from the root, âtarââ¦that thick, black sticky stuff.
Advanced Search. A positron emission tomography (PET) scan is a unique type of imaging test that helps doctors see how the organs and tissues inside your body are actually functioning.The test involves injecting a very small dose of a radioactive chemical, called a radiotracer, into the vein of your arm.ne of the main differences between PET scans and other imaging tests like CT scan or magnetic resonance imaging (MRI) is that the PET scan reveals the cellular level metabolic changes occurring in an organ or tissue.