Abstract: A method for forming a flush architectural wooden door using at least one post-consumer material includes collecting a previously-used door from a collection site. The previously-used door includes a core having a first major surface, a second major surface opposite to the first major surface, and a perimeter extending around the opposing major surfaces. The core is extracted from the previously-used door. Rails and styles are applied to a perimeter of the extracted core. A first skin is applied over the first major surface of the extracted core and applied rails and styles. The extracted core, rails, styles, and first skin have a collective weight. The extracted core forms over half of that collective weight.

Abstract: A method for forming a flush architectural wooden door using at least one post-consumer material includes collecting a previously-used door from a collection site. The previously-used door includes a core having a first major surface, a second major surface opposite to the first major surface, and a perimeter extending around the opposing major surfaces. The core is extracted from the previously-used door. Rails and styles are applied to a perimeter of the extracted core. A first skin is applied over the first major surface of the extracted core and applied rails and styles. The extracted core, rails, styles, and first skin have a collective weight. The extracted core forms over half of that collective weight.

Abstract: A method for forming a flush architectural wooden door using at least one post-consumer material includes collecting a previously-used door from a collection site. The previously-used door includes a core having a first major surface, a second major surface opposite to the first major surface, and a perimeter extending around the opposing major surfaces. The core is extracted from the previously-used door. Rails and styles are applied to a perimeter of the extracted core. A first skin is applied over the first major surface of the extracted core and applied rails and styles. The extracted core, rails, styles, and first skin have a collective weight. The extracted core forms over half of that collective weight.

Abstract: A method of and an apparatus for detecting and accurately measuring the mean concentrations of .sup.222 Rn and .sup.220 Tn in a gas mixture, such as the ambient atmosphere in a mine, is provided. The apparatus includes an alpha target member which defines at least one operative target surface and which is preferably fabricated from a single piece of an alpha particle sensitive material. At least one portion of the operative target surface is covered with an alpha particle filter. The uncovered and filter covered operative surface is exposed to the gas mixture containing the .sup.222 Rn and .sup.220 Tn. In the radioactive decay series of these isotopes the maximum kinetic energy emitted by the alpha decay of .sup.222 Rn is about 1.1 MeV less than the maximum kinetic energy emitted by the alpha decay of a .sup.220 Tn. The alpha particle filter has a predetermined mass per unit area of the covered portion of the operative target surface that prevents penetration of alpha particles which originate from .sup.