Abstract: A method for determining a wavefront parameter of a patterning process. The method includes obtaining a reference performance (e.g., a contour, EPE, CD) of a reference apparatus (e.g., a scanner), a lens model for a patterning apparatus configured to convert a wavefront parameter of a wavefront to actuator movement, and a lens fingerprint of a tuning apparatus (e.g., a to-be-matched scanner). Further, the method involves determining the wavefront parameter (e.g., a wavefront parameter such as tilt, offset, etc.) based on the lens fingerprint of the tuning apparatus, the lens model, and a cost function, wherein the cost function is a difference between the reference performance and a tuning apparatus performance.

Abstract: An endless drive track for a snowmobile is provided with traction lugs that are inclined relative to normal to the track base. When the traction lugs are inclined away from the direction of travel for the track, the traction lugs can compress the snow before engaging the snow for traction, thereby providing lift for a snowmobile traveling in deep snow. Second traction lugs, angled opposite the first, provide hard snow traction and long traction life.

Abstract: An endless drive track for a snowmobile is provided with traction lugs that are inclined relative to normal to the track base. When the traction lugs are inclined away from the direction of travel for the track, the traction lugs can compress the snow before engaging the snow for traction, thereby providing lift for a snowmobile traveling in deep snow.

Abstract: An endless drive track for a snowmobile is provided with traction lugs that are inclined relative to normal to the track base. When the traction lugs are inclined away from the direction of travel for the track, the traction lugs can compress the snow before engaging the snow for traction, thereby providing lift for a snowmobile traveling in deep snow. Second traction lugs, angled opposite the first, provide hard snow traction and long traction life.

Abstract: An endless drive track for a snowmobile is provided with traction lugs that are inclined relative to normal to the track base. When the traction lugs are inclined away from the direction of travel for the track, the traction lugs can compress the snow before engaging the snow for traction, thereby providing lift for a snowmobile traveling in deep snow.

Abstract: A piston/connecting rod assembly is provided for an internal combustion engine. The piston has a piston pin bore which receives a piston pin. An end of a connecting rod has a connecting rod bore which receives the piston pin, and the wall of the connecting rod bore directly engages the piston pin, without a bushing therebetween. The connecting rod bore is symmetrical, and has a diameter which varies from a smaller uniform diameter central portion to a larger diameter portions at either end thereof. The connecting rod bore also has a profile which is symmetrical about a central plane which is perpendicular to a central axis of the connecting rod bore, and which is elliptical or quasi-elliptical on either side of a central uniform diameter portion.