FLEXTURE POSTURING SKIN
In addition, she showed mild skin laxity, sparse woolly hair, and sparse eyebrows. Dysmorphic features included hypotelorism, bilateral infraorbital creases, left convergent squint, long philtrum, thin upper lip, and prominent nose. She had mild spasticity, and MRI showed delayed myelination and periventricular diffusion restriction at the optic radiation.
One was an Indian girl (TTD236AM) who upon examination at 8 months of age had only partial head control and showed height, weight, and head circumference in the 3rd centile or below. (2021) identified 2 unrelated patients with nonphotosensitive trichothiodystrophy and mutation in the AARS1 gene. Trichocutaneous findings were unchanged, but the authors stated that the skin was highly photosensitive.īotta et al. At age 4 years, the proband showed severely impaired intellectual development and growth parameters were still below the 3rd centile. Neurologic findings included jerky ocular pursuit movements with titubation of the head, spastic diplegia, extensor plantar reflexes, and absent deep tendon reflexes. His skin was ichthyotic with severe flexural eczema. His face was unusual with receding chin and protruding ears, and his eyebrow hair was stubby, but eyelashes were normal. At 6 months he presented with developmental delay, at which time length, weight, and head circumference were below the 3rd centile. (1984) reported a boy (case 1), offspring of nonconsanguineous Scottish parents, who was born with short, woolly hair that fell out easily. Weinstein, Warren D., "Microperformance of Metals".King et al.Weinstein, Warren D., "Flexure-Pivot Bearings", Machine Design, Part 1, June 10, 1965, Part 2, JSpring rates, bearing types, single and multi-strip design, material types, hysteresis and fatigue.Also includes an e-book library of classic texts on mechanical design and engineering.
Kinematic Models for Design Digital Library (KMODDL) - Movies and photos of hundreds of working mechanical-systems models at Cornell University.Parasitic Error-free Symmetric Diaphragm Flexure, and a set of precision compliant mechanisms based it: Three and Five DOF flexible torque couplings, Five DOF motion stage, single DOF linear/axial bearing (PDF) (Report).
2014 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2014). "Principles of Microscale Flexure Hinge Design for Enhanced Endurance" (PDF). For this reason, flexure bearings are often used in sensitive precision measuring equipment. A flexure bearing operates by bending of materials, which causes motion at microscopic level, so friction is very uniform. Many other bearings rely on sliding or rolling motions ( rolling-element bearings), which are necessarily uneven because the bearing surfaces are never perfectly flat. Thus, one part of flexure bearing design is the careful consideration of material properties to avoid fatigue with normal use.įlexure bearings can give very low friction and also give very predictable friction. For example, most metals will fatigue with repeated flexing, and will eventually snap. However, most materials lose strength and eventually fail with repeated flexing and bending. Flexure bearings have the disadvantages that the range of motion is limited, and often very limited for bearings that support high loads.Ī flexure bearing relies on the bearing element being made of a material which can be repeatedly flexed without disintegrating. They are also often compact, lightweight, have very low friction, and are easier to repair without specialized equipment. This hinge has one compliant degree of freedom.įlexure bearings have the advantage over most other bearings that they are simple and thus inexpensive. A living hinge (a type of flexure) on the lid of a Tic Tac box.
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