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A tracheoesophageal fistula (TEF, or TOF; see spelling differences) is an abnormal connection between the esophagus and the trachea. TEF is a common congenital abnormality, but when occurring late in life is usually the sequela of surgical procedures such as a laryngectomy .
A swing check valve (or tilting disc check valve) is a check valve in which the disc, the movable part to block the flow, swings on a hinge or trunnion, either onto the seat to block reverse flow or off the seat to allow forward flow. The seat opening cross-section may be perpendicular to the centerline between the two ports or at an angle.
Valves can be categorized also based on their function: Check valve or non-return valve, allows the fluid to pass in one direction only; Flow control valve, to maintain and control a variable flow rate through the valve; Poppet valve, commonly used in piston engines to regulate the fuel mixture intake and exhaust; Pressure-balanced valve
The Teaching Excellence and Student Outcomes Framework (TEF) is a government assessment of the quality of undergraduate teaching in universities and other higher education providers in England, which may be used from 2020 to determine whether state-funded providers are permitted to raise tuition fees.
The active valve control system (AVCS) is an automobile variable valve timing technology used by Subaru. It varies the timing of the valves by using hydraulic oil pressure to rotate the camshaft, known as "phasing", [1] in order to provide optimal valve timing for engine load conditions. The system is closed loop using the camshaft sensors ...
A double check valve or double check assembly (DCA) is a backflow prevention device designed to protect water supplies from contamination. [1] It is different from the two-way check valves (sometimes erroneously referred to as double check valves) used in air brake systems on heavy trucks which select from the highest pressure source.
Specific dynamic action (SDA), also known as thermic effect of food (TEF) or dietary induced thermogenesis (DIT), is the amount of energy expenditure above the basal metabolic rate due to the cost of processing food for use and storage. [1]
Toxic equivalency factor (TEF) expresses the toxicity of dioxins, furans and PCBs in terms of the most toxic form of dioxin, 2,3,7,8-TCDD. [1] The toxicity of the individual congeners may vary by orders of magnitude .