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Hyperkalemia is an elevated level of potassium (K +) in the blood. [6] [1] Normal potassium levels are between 3.5 and 5.0 mmol/L (3.5 and 5.0 mEq/L) with levels above 5.5 mmol/L defined as hyperkalemia. [3] [4] Typically hyperkalemia does not cause symptoms. [1] Occasionally when severe it can cause palpitations, muscle pain, muscle weakness ...
The stress and strain can be normal, shear, or a mixture, and can also be uniaxial, biaxial, or multiaxial, and can even change with time. The form of deformation can be compression, stretching, torsion, rotation, and so on. If not mentioned otherwise, stress–strain curve typically refers to the relationship between axial normal stress and ...
Hyperkalemic periodic paralysis causes episodes of extreme muscle weakness, with attacks often beginning in childhood. [1] Depending on the type and severity of the HyperKPP, it can increase or stabilize until the fourth or fifth decade where attacks may cease, decline, or, depending on the type, continue on into old age.
The relationship between stress and strain can be simplified for specific stress or strain rates. For high stress or strain rates/short time periods, the time derivative components of the stress–strain relationship dominate. In these conditions it can be approximated as a rigid rod capable of sustaining high loads without deforming.
Other models may also include the effects of strain gradients. [3] Independent of test conditions, the flow stress is also affected by: chemical composition, purity, crystal structure, phase constitution, microstructure, grain size, and prior strain. [4] The flow stress is an important parameter in the fatigue failure of ductile materials.
The Ramberg–Osgood equation was created to describe the nonlinear relationship between stress and strain—that is, the stress–strain curve—in materials near their yield points. It is especially applicable to metals that harden with plastic deformation (see work hardening), showing a smooth elastic-plastic transition.
The general trend given by the Goodman relation is one of decreasing fatigue life with increasing mean stress for a given level of alternating stress. The relation can be plotted to determine the safe cyclic loading of a part; if the coordinate given by the mean stress and the alternating stress lies under the curve given by the relation, then ...
While temperature is related to the rate of diffusion, strain rate determines the time the dislocations take to overcome these obstacles, and has a dramatic effect on the conditions of the PLC effect. So generally, the critical stress will decrease with imposed strain rate. [3] Also the higher the stress rate, the lower the band speed. [2]