Abstract: In the case of a gas in which several gases are mixed, a type and concentration of the gas may be incorrectly measured when measured using only an optical band-pass filter. The invention of the present application is directed to providing a technology in which a plurality of broadband band-pass filters having overlapping regions are provided to calculate a magnitude of absorption for each wavelength band for light passing through each broadband band-pass filter, thereby identifying the presence of a gas of interest and the presence of a gas other than the gas of interest.

Abstract: A reusable envelope has a front address panel and a rear panel joined along three edges to form a pocket with an open top. A first extended sealing flap joined to the top edge of the address panel is provided with a tear strip formed by a line of perforations extending across the top edge of the envelope and through the flap. A second sealing flap is provided which is foldably connected to the top edge of the rear panel and is initially either folded and retained inside the envelope pocket or against the exterior of the rear panel for the first mailing, and is folded over and onto the first panel for the second use. The second flap has an adhesive area securing means for sealing the envelope when the flap is positioned on the address panel for a further mailing. The address panel is provided with an area for postage indicia and, is optionally provided with a first return address area adjacent the top edge of the address panel.

Abstract: A reusable envelope has a front address panel and a rear panel joined along three edges to form a pocket with an open top. A first extended sealing flap joined to the top edge of the address panel is provided with a tear strip formed by a line of perforations extending across the top edge of the envelope and through the flap. A second sealing flap is provided which is foldably connected to the top edge of the rear panel and is initially either folded and retained inside the envelope pocket or against the exterior of the rear panel for the first mailing, and is folded over and onto the first panel for the second use. The second flap has an adhesive area securing means for sealing the envelope when the flap is positioned on the address panel for a further mailing. The address panel is provided with an area for postage indicia and, is optionally provided with a first return address area adjacent the top edge of the address panel.

Abstract: A reusable envelope has a front address panel and a rear panel joined along three edges to form a pocket with an open top. A first extended sealing flap joined to the top edge of the address panel is provided with a tear strip formed by a line of perforations extending across the top edge of the envelope and through the flap. A second sealing flap is provided which is foldably connected to the top edge of the rear panel and is initially either folded and retained inside the envelope pocket or against the exterior of the rear panel for the first mailing, and is folded over and onto the first panel for the second use. The second flap has an adhesive area securing means for sealing the envelope when the flap is positioned on the address panel for a further mailing. The address panel is provided with an area for postage indicia and, is optionally provided with a first return address area adjacent the top edge of the address panel.

Abstract: A reusable envelope has a front address panel and a rear panel joined along three edges to form a pocket with an open top. A first extended sealing flap joined to the top edge of the address panel is provided with a tear strip formed by a line of perforations extending across the top edge of the envelope and through the flap. A second sealing flap is provided which is foldably connected to the top edge of the rear panel and is initially either folded and retained inside the envelope pocket or against the exterior of the rear panel for the first mailing, and is folded over and onto the first panel for the second use. The second flap has an adhesive area securing means for sealing the envelope when the flap is positioned on the address panel for a further mailing. The address panel is provided with an area for postage indicia and, is optionally provided with a first return address area adjacent the top edge of the address panel.

Abstract: A reusable envelope has a front address panel and a rear panel joined along three edges to form a pocket with an open top. A first extended sealing flap joined to the top edge of the address panel is provided with a tear strip formed by a line of perforations extending across the top edge of the envelope and through the flap. A second sealing flap is provided which is foldably connected to the top edge of the rear panel and is initially either folded and retained inside the envelope pocket or against the exterior of the rear panel for the first mailing, and is folded over and onto the first panel for the second use. The second flap has an adhesive area securing means for sealing the envelope when the flap is positioned on the address panel for a further mailing. The address panel is provided with an area is for postage indicia and, is optionally provided with a first return address area adjacent the top edge of the address panel.

Abstract: A reusable envelope includes first, second and third panels, the first panel being joined to the second panel along a definition line and the second panel being joined to the third panel along a fold line. The second panel has a first tear line spaced from the fold line by a predetermined distance to define a first area and the third panel has a second tear line spaced from the fold line by the predetermined distance to define a second area. The first and second panels are folded along the definition line, and the second and third panels are folded along the fold line such that the first and second tear lines are collinear, the first area being sealed to the second area to define a tear strip that is removable along the collinear tear lines to at least partially create a second envelope for remailing.

Abstract: A re-mailable envelope is provided with a bodily removable front cover and a closure flap arrangement providing first and second sealing areas for sealing to the back panel of the envelope during first and second mailings. The outer front cover and the main front panel of the envelope have aligned windows for displaying address information provided on the contents of the envelope. At destination, the first addressee bodily removes the entire front cover, along with the original postage, cancellations marks etc., and also opens the envelope in a way that leaves the sealing flap means intact, along with an adhesive area thereon for resealing of the envelope for its second mailing. The envelope is characterized by simplicity and economy of construction and ease of use. In one form, "round trip" postage is provided, which avoids the need for a removable front panel.