Provided herein is a polyurethane tube having a small bending repulsive stress and superior inner-pressure creep characteristics in a flexible polyurethane tube. The present polyurethane tube has a bending repulsive stress of 0.035 N/mm.sup.2 or less, wherein the polyurethane tube is formed so that the difference between the storage elastic modulus E.sub.30 at 30 C. and the storage elastic modulus E.sub.80 at 80 C. is 15% or less of E.sub.30.

A tunnel spring structure three-dimensionally printed on a base layer. The tunnel spring structure includes three tubular structures and two connecting portions. A connecting portion is disposed between two tubular structures. A tensile strand extends through the tubular structures. Tension applied to the tensile strand forces the tubular structures to adjoin due to the flexibility of the connection portions.

A method of forming a printed structure is disclosed. The method may include printing layers of a printed structure and incorporating an element within the printed structure. The element may be removed in order to form tunnels within the printed structure. In some embodiments the element may be removed and reused in the formation of additional printed structures. The element may also be retained to form a composite printed structure.

Systems and methods are provided for ultrasonic imaging of composite parts. One embodiment is a method that includes providing an object having multiple layers of fibers and resin, inducing ultrasonic waves at locations along the object, and attenuating the ultrasonic waves at the regions due to regions interspersed among the layers that each exhibit an elastic modulus distinct from an elastic modulus of the fibers and distinct from an elastic modulus of the matrix. The method further includes receiving the attenuated ultrasonic waves, and analyzing the attenuated ultrasonic waves to determine depths of the regions.

A sporting equipment is disclosed. The sporting equipment may include a harness, and a protective plate. The protective plate may be integrally formed with the harness from a plurality of fibers that are continuous from the harness into the protective plate.

A plastic molded lip structure may extend along a perimeter of a planar element and may include an outer wall, an inner wall, structural portions, and protruded features. The outer wall may extend in a normal direction from the planar element. The inner wall may be disposed in an inward direction relative to the outer wall. The structural portions may be disposed along structural sections of the perimeter and may include first portions of the inner wall and of the outer wall. The first portions may be disposed parallel to the inner wall and separated from the first portions by a first distance along the structural sections. The protruded features may be interposed between two structural portions and an inner wall may be separated from second portions of the outer wall by a second distance that is greater than the first distance.

A structure, such as a tabletop, may be constructed from blow-molded plastic. The tabletop may include an upper surface, a lower surface, and a hollow interior portion disposed between the upper surface and the lower surface. A lip may extend downwardly relative to the lower surface of the tabletop, and the lip including an outer surface and an inner surface. One or more supports may be disposed in the inner surface of the lip, and one or more joints may be disposed in the inner surface of the lip. A joint may be disposed between adjacent supports, and a distal portion of the lip may include a compression edge. A lower portion of the supports may contact the compression edge, and/or a lower portion of the joints may contact the compression edge.

The present disclosure provides a light curing non-transparent material for 3D printing and a preparation method thereof, a 3D printed product and a 3D printer. The light curing non-transparent material for 3D printing provided by the present disclosure can be used to print non-transparent 3D printed products without adding white pigments such as white pigments powder, and therefore has the characteristic of high stability, and also ensures fluency of the 3D printing process, good quality of the 3D printed products, as well as good performances of the 3D printer that containing light curing non-transparent material for 3D printing.

A device (10) comprising a carrier material (14) and a matrix material (12) deposited onto the carrier material in a pattern that leaves a predetermined amount of space (18) between each deposition of matrix material.

The present invention provides improved devices, systems and methods for repositioning teeth from an initial tooth arrangement to a final tooth arrangement. Repositioning is accomplished with a system comprising a series of polymeric shell appliances configured to receive the teeth and incrementally reposition individual teeth in a series of successive steps. The individual appliances may be formed from layers having different stiffnesses (elastic moduluses), and the stiffnesses of successive appliances may be different, or both.