Internal energyThe internal energy of a thermodynamic system is the energy contained within it, measured as the quantity of energy necessary to bring the system from its standard internal state to its present internal state of interest, accounting for the gains and losses of energy due to changes in its internal state, including such quantities as magnetization. It excludes the kinetic energy of motion of the system as a whole and the potential energy of position of the system as a whole, with respect to its surroundings and external force fields.
Stress managementStress management consists of a wide spectrum of techniques and psychotherapies aimed at controlling a person's level of stress, especially chronic stress, usually for the purpose of improving everyday functioning. Stress produces numerous physical and mental symptoms which vary according to each individual's situational factors. These can include a decline in physical health, such as headaches, chest pain, fatigue, and sleep problems, as well as depression.
Relaxation (psychology)In psychology, relaxation is the emotional state of low tension, in which there is an absence of arousal, particularly from negative sources such as anger, anxiety, or fear. Relaxation is a form of mild ecstasy coming from the frontal lobe of the brain in which the backward cortex sends signals to the frontal cortex via a mild sedative. Relaxation can be achieved through meditation, autogenics, breathing exercises, progressive muscle relaxation and other means. Relaxation helps improve coping with stress.
Theorema EgregiumGauss's Theorema Egregium (Latin for "Remarkable Theorem") is a major result of differential geometry, proved by Carl Friedrich Gauss in 1827, that concerns the curvature of surfaces. The theorem says that Gaussian curvature can be determined entirely by measuring angles, distances and their rates on a surface, without reference to the particular manner in which the surface is embedded in the ambient 3-dimensional Euclidean space. In other words, the Gaussian curvature of a surface does not change if one bends the surface without stretching it.
WaterproofingWaterproofing is the process of making an object or structure waterproof or water-resistant so that it remains relatively unaffected by water or resisting the ingress of water under specified conditions. Such items may be used in wet environments or underwater to specified depths. Water-resistant and waterproof often refer to resistance to penetration of water in its liquid state and possibly under pressure, whereas damp proof refers to resistance to humidity or dampness.
NeopreneNeoprene (also polychloroprene) is a family of synthetic rubbers that are produced by polymerization of chloroprene. Neoprene exhibits good chemical stability and maintains flexibility over a wide temperature range. Neoprene is sold either as solid rubber or in latex form and is used in a wide variety of commercial applications, such as laptop sleeves, orthopaedic braces (wrist, knee, etc.), electrical insulation, liquid and sheet-applied elastomeric membranes or flashings, and automotive fan belts.
