Michael A. Galler

Measurements and predictions of light scattering by clear coatings

Comparisons are made between calculated and measured angle-resolved light-scattering distributions from clear dielectric isotropic epoxy coatings over a range of rms roughness conditions, resulting in strongly specular scattering to diffuse scattering characteristics. Calculated distributions are derived from topography measurements performed with interferometric microscopes. Two methods of calculation are used. One determines the intensity of scattered light waves with a phase integral in the Kirchhoff approximation. The other is based on the reflection of light rays by locally flat surfaces. The angle-resolved scattering distributions for the coatings are measured with the spectral trifunction automated reference reflectometer (STARR) developed by the National Institute of Standards and Technology. Comparisons between measured and calculated results are shown for three surfaces with rms roughness values of approximately 3, 150, and 800 nm for an angle of incidence of 20 degrees .

Microstructure of weathered paint and its relation to gloss loss: Computer simulation and modeling

The role of pigment particle size, pigment volume concentration, and dispersion in gloss loss of paint films on weathered surfaces is unclear. Because reproducible and cost effective data are difficult to obtain, an approach based on computer simulation and modeling is a promising supplementary tool. We describe the simulation of a painted surface consisting of pigment particles of known size, pigment volume concentration and dispersion, situated in a binder that erodes over time due to exposure to ultraviolet radiation. Pigment particle size, geometry, pigment volume concentration, and pigment particle dispersion are parameters of the model. Our purpose is to illustrate how simulation can be used to aid the development of formulation strategies for the design of coatings with desirable gloss characteristics.

Evaluating the performance of Diagnostic Agent for Building Operation (DABO) and HVAC-Cx tools using the Virtual Cybernetic Building Testbed

Automated commissioning tools are designed to facilitate the commissioning process, thereby decreasing the time and the skill level required to carry out necessary quality control measures. As a result, they enable more thorough testing of building HVAC systems to improve occupant comfort and the persistence of correct system operation. As a part of the International Energy Agencys Annex 47 research project, two tools were developed to perform automated commissioning: (1) the Diagnostic Agent for Building Operation (DABO) tool, developed by Natural Resources Canada, and (2) the heating ventilating and air-conditioning (HVAC) system commissioning tool, HVAC-Cx, developed by the U.S. National Institute of Standards and Technology. This article investigates the performance of these automated commissioning tools for the ongoing commissioning of air-handling units using data from the U.S. National Institute of Standards and Technology Virtual Cybernetic Building Testbed as a means to conduct a repeatable evaluation over a range of operating conditions.