Abstract: Glass frit compositions are shown that are lead-free, cadmium-free, and zinc-free, the compositions having improved chemical resistance, especially acid resistance (acetic acid) of a loss of generally less than about 1.9% by weight. The compositions contain B.sub.2 O.sub.3, SiO.sub.2, ZrO.sub.2 and rare earth oxides, the weight ratio of ZrO.sub.2 to rare earth oxides being critical and being about 1/1 to 1.4/1.

Abstract: Glass frits for use in glazes or enamels have fiber softening point about 535.degree.-609.degree. C. are free of lead, cadmium and zinc and consist essentially of Li.sub.2 O-B.sub.2 O.sub.3 -SiO.sub.3 plus 2-23% SnO.sub.2 +CaO and 2-23% ZrO.sub.2 +La.sub.2 O.sub.3 ; also, Al.sub.2 O.sub.3, SrO, BaO, Na.sub.2 O, F.Low expansion filler, e.g., B-eucryptite, may be used at 4 to 15% by weight of glass frit.

Abstract: A core sample orientation tool for coupling to push rods or wire lines for use in obtaining core impressions in bore holes. The tool includes a putty cup and mark receiving surface which are removably attached to a sleeve housing a pendulum-oriented marker which marks the mark receiving surface when a core impression is taken to indicate a chosen directional reference. The removed putty cup and mark receiving surface can be used to orient a previously drilled core or the core to be drilled next, and when the core is laid out on a table in the proper up-down relationship, and considered in conjunction with bore hole logging techniques, the strike and dip of planar core features can be translated into actual attitudes in space.

Abstract: Thermally crystallizable glasses and glass-ceramics having a narrow critical range of compositions coming within the SiO.sub.2 -Al.sub.2 O.sub.3 -Li.sub.2 O and SiO.sub.2 -Al.sub.2 O.sub.3 -Li.sub.2 O-ZnO systems and glass-ceramic products made therefrom including heat exchangers, such as regenerators and recuperators used with gas turbine engines, thermal reactors and catalytic reactors for the gaseous exhausts of combustion engines, and other products which are dimensionally stable at temperatures of at least 1500.degree.F. and above, have very low coefficients of thermal expansion, and have a modulus of rupture of at least about 10,000 psi which is retained when operating at temperatures of at least 1500.degree.F., over an extended period of time.