* In haptotaxis the gradient of the chemoattractant is expressed or bound on a surface, in contrast to the classical model of chemotaxis, in which the gradient develops in a soluble fluid.

Another often used model, especially in computational fluid dynamics, is to use the Euler equations away from the body and the boundary layer equations, which incorporates viscosity, in a region close to the body.

This completed the classic empirical model of friction ( static, kinetic, and fluid ) commonly used today in engineering.

36, Nov. 1998 THE PHYSICS TEACHER – using a physical model relying only on Newton ’ s second law, the author presents a rigorous fluid dynamical treatment of flight.

George Gabriel Stokes became a champion of the entrainment interpretation, developing a model in which the aether might be ( by analogy with pine pitch ) rigid at very high frequencies and fluid at lower speeds.

The entrepreneurial model looks at either the individual criminal, or a smaller group of organised criminals, that capitalise off the more fluid ' group-association ' of contemporary organised crime.

Together with supplemental equations ( for example, conservation of mass ) and well formulated boundary conditions, the Navier – Stokes equations seem to model fluid motion accurately ; even turbulent flows seem ( on average ) to agree with real world observations.

Bernoulli's principle, which is a function of the velocity of the fluid, is a dominant effect for large openings and large flow rates, but since fluid flow at small scales and low speeds ( low Reynolds number ) is dominated by viscosity, Bernoulli's principle is ineffective at idle or slow running and in the very small carburetors of the smallest model engines.

* 1972 — Seymour Jonathan Singer and Garth L. Nicholson developed the fluid mosaic model, which deals with the make-up of the membrane of all cells.

Therefore, the viscosity and friction of the liquid in this model do not play a role, since these quantities would play a role only for a moving fluid.

While this force in the rigid model depends only on the radius r of the satellite, in the fluid case we need to consider all the points on the surface and the tidal force depends on the distance Δd from the center of mass to a given particle projected on the line joining the satellite and the main body.

Vector fields are often used to model, for example, the speed and direction of a moving fluid throughout space, or the strength and direction of some force, such as the magnetic or gravitational force, as it changes from point to point.

Lakoff's reliance on empirical scientific evidence, i. e. specifically falsifiable predictions, in the 1987 work and in Philosophy in the Flesh ( 1999 ) suggests that the cognitive-metaphor position has no objections to the scientific method, but instead considers the scientific method a finely developed reasoning system used to discover phenomena which are subsequently understood in terms of new conceptual metaphors ( such as the metaphor of fluid motion for conducted electricity, which is described in terms of " current " " flowing " against " impedance ," or the gravitational metaphor for static-electric phenomena, or the " planetary orbit " model of the atomic nucleus and electrons, as used by Niels Bohr ).

In the nineteenth century, James Clerk Maxwell developed a model of electromagnetism in which magnetic field lines were rotating tubes of incompressible fluid.

The first three are closely linked to fluid ability, and the verbal and spatial abilities that form the hierarchical model of intelligence

This model, which can be represented by the Friedmann equations, provides a curvature ( often referred to as geometry ) of the universe based on the mathematics of fluid dynamics, i. e. it models the matter within the universe as a perfect fluid.

In relativistic cosmology, Weyl's postulate stipulates that in a fluid cosmological model, the world lines of the fluid particles, which act as the source of the gravitational field and which are often taken to model galaxies, should be hypersurface orthogonal.

In contrast to the Fiedler contingency model, the path-goal model states that the four leadership behaviors are fluid, and that leaders can adopt any of the four depending on what the situation demands.

Atmospheric physicists attempt to model Earth's atmosphere and the atmospheres of the other planets using fluid flow equations, chemical models, radiation balancing, and energy transfer processes in the atmosphere and underlying oceans.

The paired Müllerian glands inside the male cloaca secrete a fluid which resembles that produced by mammalian prostate glands and which may transport and nourish the sperm.

Lumbar puncture procedure, which is performed in many infectious disorders of the central nervous system is contraindicated in this condition ( as it is in all space-occupying lesions of the brain ) because removing a certain portion of the cerebrospinal fluid may alter the concrete intracranial pressure balances and causes the brain tissue to move across structures within the skull ( brain herniation ).

This increase in glycerol has been postulated to be responsible for the lubricating quality of this fertile cervical fluid and may be biologically relevant during the early phase of reproductive events.

It may be a liquid ( LC and Capillary Electrochromatography ( CEC )), a gas ( GC ), or a supercritical fluid ( supercritical-fluid chromatography, SFC ).

Ten percent of a person's body weight in fluid may need to be given in the first two to four hours.

AVMs in certain critical locations may stop the circulation of the cerebrospinal fluid, causing accumulation of the fluid within the skull and giving rise to a clinical condition called hydrocephalus.

The mass is normally measured with an appropriate scale or balance ; the volume may be measured directly ( from the geometry of the object ) or by the displacement of a fluid.

Transport of material in stagnant fluid or across streamlines of a fluid in a laminar flow occurs by molecular diffusion. Two adjacent compartments, separated by partition containing pure gases A or B may be envisaged.

For example, it may go from having only periodic motions to apparently erratic behavior, as in the transition to turbulence of a fluid.

A heat engine may also serve as a prime mover, a component that transforms the flow or changes in pressure of a fluid into mechanical energy.

There are then two types of work performed: flow work described above, which is performed on the fluid ( this is also often called pV work ), and shaft work, which may be performed on some mechanical device.

Oversize particles may form a cake layer on top of the filter and may also block the filter lattice, preventing the fluid phase from crossing the filter ( blinding ).

Hall effect sensors are readily available from a number of different manufacturers, and may be used in various sensors such as rotating speed sensors ( bicycle wheels, gear-teeth, automotive speedometers, electronic ignition systems ), fluid flow sensors, current sensors, and pressure sensors.

Non-streamlined objects such as bluff bodies and flat plates may also generate lift when moving relative to the fluid, but will have a higher drag coefficient dominated by pressure drag.

In the industrial market place the specification may take the form of a legal contract to supply a conforming fluid or purchasers may choose to buy on the basis of a manufacturers own published specification.

Lubricant persistence in the environment largely depends upon the base fluid, however if very toxic additives are used they may negatively affect the persistence.

When a fluid is flowing through a closed channel such as a pipe or between two flat plates, either of two types of flow may occur depending on the velocity of the fluid: laminar flow or turbulent flow.

Symptoms may include severe fatigue, a heavy swollen limb or localized fluid accumulation in other body areas, including the head or neck, discoloration of the skin overlying the lymphedema, and eventually deformity ( elephantiasis ).

Otherwise, bodies may be semi-rigid, i. e. elastic, or non-rigid, i. e. fluid.

Piston-type gauges counterbalance the pressure of a fluid with a spring ( for example tire-pressure gauges of comparatively low accuracy ) or a solid weight, in which case it is known as a deadweight tester and may be used for calibration of other gauges.

Models attempting to explain accelerating expansion include some form of dark energy, dark fluid or phantom energy.

For example, the entire process of blowing out a candle by a puff of air is readily explained by vortex dynamics but is much more complicated to explain using the usual primitive variables of fluid flow theory such as pressure and velocity.

, most theories trying to explain the structure of mid-latitude eddies took as their starting points the high Rossby number or small Richardson number instabilities familiar to fluid dynamicists at that time.

Some experiments have demonstrated that static fluid pressure may explain the presence of hydrocarbon concentrations at depths where their composition would not otherwise be expected.

:" Since classical inviscid theory leads to the patently absurd conclusion that the resistance experienced by a rigid body moving through a fluid with uniform velocity is zero, great efforts have been made during the last hundred or so years to propose alternate theories and to explain how a vanishingly small frictional force in the fluid can nevertheless have a significant effect on the flow properties.

He was the first scientist to explain mathematically the origin of aerodynamic lift, through his circulation hypothesis, the first to dimension the lift force generated by a body moving through an ideal fluid as proportional to the velocity and the circulation around the body, and through a mathematical conformal transformation the first to define the shape of the aerodynamic profile having as essential elements a rounded nose ( leading edge ), double surface ( finite thickness ), cambered or symmetrical, and a sharp tail ( trailing edge ).

Cattell theorized the existence of fluid and crystallized intelligences to explain human cognitive ability, and authored the Culture Fair Intelligence Test to minimize the bias of written language and cultural background in intelligence testing.

In particular, he praised closeted-homosexual Mr. Garrison's claim that gay people are evil and have a " black vomitous fluid " running through their veins, and the moment when Jesus was about to explain his feelings regarding homosexuality only to be cut off by " Marty's Movie Reviews ".

He stated: the Mid-Atlantic Ridge ... zone in which the floor of the Atlantic, as it keeps spreading, is continuously tearing open and making space for fresh, relatively fluid and hot sima from depth .< ref > However, Wegener did not pursue this observation in his later works and his theory was dismissed by geologists because there was no mechanism to explain how continents could plow through ocean crust, and the theory became largely forgotten.

According to Viany, while Cinema Novo was initially " as fluid and undefined " as its predecessor French New Wave, it required that filmmakers have a passion for cinema, a desire to use it to explain " social and human problems ," and a willingness to individualize their work.