4,752 research outputs found
New package for Belleville spring permits rate change, easy disassembly
A spring package, with grooves to hold the spring washers at the inner and outer edges, reduces hysteresis to a minimum. Three-segment retainers permit easy disassembly so that the spring rate can be changed
Packless valve with all-metal seal handles wide temperature, pressure range
A durable line valve utilizes stacked metal disks to seal off an inlet port. No packing or shaft sealing is needed, and the valve operates satisfactorily over a wide temperature and pressure range
Improved fluid control valve extends diaphragm life
Wear resistance of flexible diaphragms in fluid control valves is increased by incorporating a soft rubber washer at the bottom of the piston, a flexible buffer between the diaphragm and the valve seat, and a fluid feedback arrangement. The stress and wear of components at the valve seat are minimized
Valve designed with elastic seat
Absolute valve closure is accomplished by a machined valve with an axially annular channel which changes the outlet passage into a thin tubular elastic seat member with a retainer backup ring. The elasticity of the seat provides tight conformity to ball irregularity
Vented piston seal prevents fluid leakage between two chambers
To prevent fluid leakage around piston seals separating two fluids under differential pressure, a venting system has been devised. Two methods may be used for venting seals through internal passages to an external low-pressure area, O-ring or split-ring seals
Generant controller development for the advanced liquid propulsion system /ALPS/
Generant controller for advanced liquid propulsion syste
Valve with ball seat spring and antiflutter baffle
Antiflutter baffle plate and star spring combination for preventing squeal and impact damage in ball check valve used for high speed flow condition
Fill valve development for the Advanced Liquid Propulsion System /ALPS/
Manually operated liquid fuel control valve for Advanced Liquid Propulsion System /ALPS
Spherical Categories
This paper is a study of monoidal categories with duals where the tensor
product need not be commutative. The motivating examples are categories of
representations of Hopf algebras and the motivating application is the
definition of 6j-symbols as used in topological field theories.
We introduce the new notion of a spherical category. In the first section we
prove a coherence theorem for a monoidal category with duals following MacLane
(1963). In the second section we give the definition of a spherical category,
and construct a natural quotient which is also spherical.
In the third section we define spherical Hopf algebras so that the category
of representations is spherical. Examples of spherical Hopf algebras are
involutory Hopf algebras and ribbon Hopf algebras. Finally we study the natural
quotient in these cases and show it is semisimple.Comment: 16 pages. Minor correction
Tensile-strength apparatus applies high strain-rate loading with minimum shock
Tensile-strength testing apparatus employs a capillary bundle through which a noncompressible fluid is extruded and a quick-release valve system. This apparatus applies the test loads at relatively constant very high strain rates with minimal shock and vibration to the tensile specimen and apparatus
- …