Abstract: A thermally stable polysiloxane composition is a cross-linked product of a Part A composition, of a Part B composition and a catalyst, the Part A composition being a polysiloxane having 60 to 75 percent by weight phenyl groups, the Part B composition being a polysiloxane having 50 to 80 percent by weight phenyl groups. The composition has the properties of optical clarity as measured by 90% or greater transmission of light of 400 nm wavelength in a 1.0 centimeter path, a refractive index at 589 nm of 1.545 or greater and still has 90% or greater transmission of light of 400 nm wavelength in a 1.0 centimeter path after exposure to 150° C. for 6 hours. The composition is well suited for application as an optically transmissive cover or lens for light emitting diodes and for use in other optical and related devices.

Abstract: A method for measuring compliance with building air quality attribute set points. The method includes the steps of sensing a first attribute of environmental air quality, setting a range of acceptable values for the first attribute, setting a penalty function for the first attribute and comparing sensed data to the first range of acceptable values. The first penalty function is applied as appropriate to assess a first set of points for the first attribute. An index value is created that is a function of the first set of points. In another aspect, the method includes sensing a second attribute, comparing the data against acceptable values and applying a second penalty function as appropriate. The index value is also a function of the second set of points. In yet another aspect, the method includes the step of sensing a first attribute at a second site.

Abstract: A thermally stable polysiloxane composition is a cross-linked product of a Part A composition, of a Part B composition and a catalyst, the Part A composition being a polysiloxane having 60 to 75 percent by weight phenyl groups, the Part B composition being a polysiloxane having 50 to 80 percent by weight phenyl groups. The composition has the properties of optical clarity as measured by 90% or greater transmission of light of 400 nm wavelength in a 1.0 centimeter path, a refractive index at 589 nm of 1.545 or greater and still has 90% or greater transmission of light of 400 nm wavelength in a 1.0 centimeter path after exposure to 150° C. for 6 hours. The composition is well suited for application as an optically transmissive cover or lens for light emitting diodes and for use in other optical and related devices.