Abstract: An abdominal exercise device includes a frame comprising top, middle, and bottom frame sections. The middle frame section has a curved shape for creating a teeter-totter movement during exercise. The device includes a headrest connected to the bottom frame section, a plurality of connectors for connecting elastic bands to the frame, and an elastic band connected to at least two connectors. The two ends of the elastic band are connected to two straps. The device creates the teeter-totter movement to exercise the abdominal muscles in response to a person lying down in supine position with the back of the head on the headrest and the feet in the two straps, the person applying a downward pressure with the feet to the straps to move the headrest from a resting position, and the person removing the downward pressure to allow the headrest to go back to the resting position.

Abstract: An abdominal exercise device includes a frame comprising top, middle, and bottom frame sections. The middle frame section has a curved shape for creating a teeter-totter movement during exercise. The device includes a headrest connected to the bottom frame section, a plurality of connectors for connecting elastic bands to the frame, and an elastic band connected to at least two connectors. The two ends of the elastic band are connected to two straps. The device creates the teeter-totter movement to exercise the abdominal muscles in response to a person lying down in supine position with the back of the head on the headrest and the feet in the two straps, the person applying a downward pressure with the feet to the straps to move the headrest from a resting position, and the person removing the downward pressure to allow the headrest to go back to the resting position.

Abstract: An abdominal exercise device includes a frame comprising top, middle, and bottom frame sections. The middle frame section has a curved shape for creating a teeter-totter movement during exercise. The device includes a headrest connected to the bottom frame section, a plurality of connectors for connecting elastic bands to the frame, and an elastic band connected to at least two connectors. The two ends of the elastic band are connected to two straps. The device creates the teeter-totter movement to exercise the abdominal muscles in response to a person lying down in supine position with the back of the head on the headrest and the feet in the two straps, the person applying a downward pressure with the feet to the straps to move the headrest from a resting position, and the person removing the downward pressure to allow the headrest to go back to the resting position.

Abstract: A container for fluids is disclosed in which the container is comprised of two flexible sheets joined so as to form a fluid reservoir. Leading from the reservoir is an exit flow channel to permit the expulsion of the fluid contents when pressure is applied to the container. When the applied pressure falls below a predetermined critical value, the exit flow channel will automatically self-seal, thus preventing further fluid flow, leakage, or spoilage. This self-sealing is achieved so long as the exit channel exhibits characteristics of width and length which are proportional to certain dimensionless parameters which are, in turn, proportional to several specific parameters which are dependent on the fluid, material of the container, and the desired context in which the container is intended for use. Thus, self-sealing can be achieved by an exit flow channel which is independent of its path (i.e., the course it follows), thus permitting great flexibility in container and exit flow channel design.