Convoluted foam cushion
Segmented foam cushion
Low profile segmented air cushion
High profile segmented air cushion
Foam and viscoelastic foam cushion
Foam and viscous fluid cushion
Honeycomb cushion
Related Research Articles
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Polyurethane refers to a class of polymers composed of organic units joined by carbamate (urethane) links. In contrast to other common polymers such as polyethylene and polystyrene, polyurethane is produced from a wide range of starting materials (monomers) and is therefore a class of polymers, rather than a distinct compound. This chemical variety allows for polyurethanes with very different physical properties, leading to an equally wide range of different applications. These include: rigid and flexible foams, varnishes and coatings, adhesives, electrical potting compounds, and fibres such as spandex and PUL. Of these, foams are the largest single application, accounting for 67% of all polyurethane produced in 2016.
An ulcer is a sore on the skin or a mucous membrane, accompanied by the disintegration of tissue. Ulcers can result in complete loss of the epidermis and often portions of the dermis and even subcutaneous fat. Ulcers are most common on the skin of the lower extremities and in the gastrointestinal tract. An ulcer that appears on the skin is often visible as an inflamed tissue with an area of reddened skin. A skin ulcer is often visible in the event of exposure to heat or cold, irritation, or a problem with blood circulation.
In materials science and continuum mechanics, viscoelasticity is the property of materials that exhibit both viscous and elastic characteristics when undergoing deformation. Viscous materials, like water, resist shear flow and strain linearly with time when a stress is applied. Elastic materials strain when stretched and immediately return to their original state once the stress is removed.
Skin grafting, a type of graft surgery, involves the transplantation of skin. The transplanted tissue is called a skin graft.
A mattress is a large, usually rectangular pad for supporting a lying person. It is designed to be used as a bed, or on a bed frame as part of a bed. Mattresses may consist of a quilted or similarly fastened case, usually of heavy cloth, containing materials such as hair, straw, cotton, foam rubber, or a framework of metal springs. Mattresses may also be filled with air or water.
Pressure ulcers, also known as pressure sores or bed sores, are localised damage to the skin and/or underlying tissue that usually occur over a bony prominence as a result of usually long-term pressure, or pressure in combination with shear or friction. The most common sites are the skin overlying the sacrum, coccyx, heels, and hips, though other sites can be affected, such as the elbows, knees, ankles, back of shoulders, or the back of the cranium.
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Memory foam consists mainly of polyurethane as well as additional chemicals increasing its viscosity and density. It is often referred to as "viscoelastic" polyurethane foam, or low-resilience polyurethane foam (LRPu). The foam bubbles or ‘cells’ are open, effectively creating a matrix through which air can move. Higher-density memory foam softens in reaction to body heat, allowing it to mold to a warm body in a few minutes. Newer foams may recover their original shape more quickly.
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Rheological Weldability (RW) of thermoplastics considers the materials flow characteristics in determining the weldability of the given material. The process of welding thermal plastics requires three general steps, first is surface preparation. The second step is the application of heat and pressure to create intimate contact between the components being joined and initiate inter-molecular diffusion across the joint and the third step is cooling. RW can be used to determine the effectiveness of the second step of the process for given materials.
Podiatrists have molded custom orthotics to address patients' foot malformations. Over the years they have developed numerous means to create the basis for their molds; plaster casts, foam box impressions, or three-dimensional computer imaging. None is very accurate: all produce proper fit under 80% of the time.Telfer S.; Gibson KS; Hennessy K; Steultjens MP; Woodburn J. (2012). "Computer-aided design of customized foot orthoses: reproducibility and effect of method used to obtain foot shape". Arch Phys Med Rehabil. 93 (5): 863–70. doi:10.1016/j.apmr.2011.12.019. PMID 22541310.</ref>
Gait deviations are nominally referred to as any variation of standard human gait, typically manifesting as a coping mechanism in response to an anatomical impairment. Lower-limb amputees are unable to maintain the characteristic walking patterns of an able-bodied individual due to the removal of some portion of the impaired leg. Without the anatomical structure and neuromechanical control of the removed leg segment, amputees must use alternative compensatory strategies to walk efficiently. Prosthetic limbs provide support to the user and more advanced models attempt to mimic the function of the missing anatomy, including biomechanically controlled ankle and knee joints. However, amputees still display quantifiable differences in many measures of ambulation when compared to able-bodied individuals. Several common observations are whole-body movements, slower and wider steps, shorter strides, and increased sway.
References
- 1 2 Ferrarin, M; Andreoni, G; Pedotti, A (2000). "Comparative biomechanical evaluation of different wheelchair seat cushions". Journal of Rehabilitation Research and Development. 37 (3): 315–24. PMID 10917263.
- ↑ Kosiak, M (1961). "Etiology of decubitus ulcers". Arch Phys Med Rehabil: 19–29.
- ↑ Stewart, SFC; Palmieri, V; Cochran, GVB (1980). "Wheel chair cushion effect on skin temperature, heat flux, and relative humidity". Arch Phys Med Rehabil. 61 (5): 229–33. PMID 7377945.
- ↑ Finestone, HM; Levine, SP; Carlson, GA; Chizinsky, KA; Kett, RL (1991). "Erythema and skin temperature following continuous sitting in spinal cord injured individuals". J Rehabil Res Dev. 28 (4): 27–32. doi: 10.1682/JRRD.1991.10.0027 . PMID 1941646.
- ↑ Bennet, L; Kavner, D; Lee, BK; Trainor, FA (1979). "Shear vs . pressure as causitive factors in skin blood occlusion". Arch Phys Med Rehabil. 60: 309–14.
- 1 2 3 Sprigle, Stephen; Press, Larry; Davis, Kim (2001). "Development of uniform terminology and procedures to describe wheelchair cushion characteristics". J Rehabil Res Dev. 38 (4): 449–61. PMID 11563498.
- ↑ Fleming, Joe. "Wheelchair Cushion: Selection and Maintenance". Vive Health. Retrieved 6 January 2017.