Abstract: An improved circle cutting tool for performing circular cuts on a wide variety of materials. Comprises a body (10) having a horizontal rotating radius bar (18) which is provided with an adjustable knife holder (20) and knife blade (30). The knife holder may be reversed for right or left handed users. The body is also provided with anchor pins (12) on the bottom and a swivel handle (38) on top.

Abstract: A transparent dispenser for nuts or the like having a movable slide which, by its movement, transfers a measured volume from the bottom of a hopper to a delivery chute. The upper wall of the slide chamber is partly relieved so as to prevent jamming of the slide.

Abstract: A system for the linear control and calibration of the flow of fluid through a pump in which the pump has a linear flow rate-to-fluid propeller speed relationship over a range of flow rates. A DC motor driving the fluid propeller has a linear drive speed-to-armature voltage relationship over a corresponding range of drive speeds. The voltage applied to the armature is regulated DC, the value of which provides an indication of the fluid flow rate. The system has particular utility in portable air pollutant measuring applications where a measured volume of air is pumped through a filter tube filled with a porous solid sorbent which is later subjected to chemical analysis.