Abstract: A head-mounted display may include a display system and an optical system in a housing. The display system may have displays that produce images. Positioners may be used to move the displays relative to the eye positions of a user's eyes. An adjustable optical system may include tunable lenses such as tunable cylindrical liquid crystal lenses. The displays may be viewed through the lenses when the user's eyes are at the eye positions. A sensor may be incorporated into the head-mounted display to measure refractive errors in the user's eyes. The sensor may include waveguides and volume holograms, and a camera for gathering light that has reflected from the retinas of the user's eyes. Viewing comfort may be enhanced by adjusting display positions relative to the eye positions and/or by adjusting lens settings based on the content being presented on the display and/or measured refractive errors.

Abstract: The present invention is for valved musical wind instruments in the musical keys of BB-flat, CC, E-flat, and F with progressive cylindrical mid-section bore or gradual conical mid-section bore expansion or a combination, not to exceed 0.85 inch bore within the first 65% of instrument length and bell throat diameters not to exceed 3 inches measured 10 inches from the bell flare, in which bass trombone tone qualities prevail. Progressive mid-section bore is novel, enhances responsiveness, and enables “early” valve placement options. A 4-valve B-flat bass valve trombone, B-flat cimbasso, or B-flat Tu-Bone is claimed, and may have a single constant cylindrical mid-section bore, or progressive cylindrical mid-section bore or gradual conical mid-section bore expansion or a combination. A valved B-flat bass inverted full double trombone, cimbasso, or Tu-Bone is claimed, as well as a “compensated” version and a full double euphonium. Invention valves may be any piston or rotary valves.

Abstract: A reservoir type electric water heating tank for containment within a void defined between the upper and lower plates, pair of spaced vertical studs and the opposing surface elements of a structural wall includes a relatively thin tank structure peripherally thermally insulated with thin rigid insulation and having a rectilinear configuration. The tank has two spaced opposed sides of substantial areal extent with vertical flutes therein to provide rigidity joined to a pair of elongate rectilinear vertical ends and horizontal top and bottom elements to define a chamber for containment of water to be heated. Structural brackets extend laterally from the upper and lower portions of the vertical ends of the tank to the peripheral surface of the thermal tank insulation and are secured by lateral extensions thereof to vertical post-like studs having laterally extending fastening brackets adapted to be secured to the plates of the structural wall.