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Adhesive materials fill the voids or pores of the surfaces and hold surfaces together by interlocking. Other interlocking phenomena are observed on different length scales. Sewing is an example of two materials forming a large scale mechanical bond, velcro forms one on a medium scale, and some textile adhesives (glue) form one at a small scale.
plasma physics (ratio of a resistive time to an Alfvén wave crossing time in a plasma) Perveance: K = charged particle transport (measure of the strength of space charge in a charged particle beam) Pierce parameter
The strength of adhesion depends on many factors, including the means by which it occurs. In some cases, an actual chemical bond occurs between adhesive and substrate. Thiolated polymers , for example, form chemical bonds with endogenous proteins such as mucus glycoproteins, integrins or keratins via disulfide bridges. [ 40 ]
Extensional rheometers, also known as extensiometers, measure viscoelastic properties by pulling a viscoelastic fluid, typically uniaxially. [28] Because this typically makes use of capillary forces and confines the fluid to a narrow geometry, the technique is often limited to fluids with relatively low viscosity like dilute polymer solutions ...
Differential adhesion hypothesis (DAH) is a hypothesis that explains cellular movement during morphogenesis with thermodynamic principles. In DAH tissues are treated as liquids consisting of mobile cells whose varying degrees of surface adhesion cause them to reorganize spontaneously to minimize their interfacial free energy . [ 1 ]
Schematic of cell adhesion. Cell adhesion is the process by which cells interact and attach to neighbouring cells through specialised molecules of the cell surface. This process can occur either through direct contact between cell surfaces such as cell junctions or indirect interaction, where cells attach to surrounding extracellular matrix, a gel-like structure containing molecules released ...
They also showed why lifespan scales as the + 1 ⁄ 4 power and heart rate as the - 1 ⁄ 4 power. Blood flow (+ 3 ⁄ 4) and resistance (-3 ⁄ 4) scale in the same way, leading to blood pressure being constant across species. [37] Hu and Hayton in 2001 discussed whether the basal metabolic rate scale is a 2 ⁄ 3 or 3 ⁄ 4 power of body mass.
The two front feet of a tokay gecko can withstand 20.1 N of force parallel to the surface with 227 mm 2 of pad area, [4] a force as much as 40 times the gecko's weight. . Scientists have been investigating the secret of this extraordinary adhesion ever since the 19th century, and at least seven possible mechanisms for gecko adhesion have been discussed over the past 17