Word Finder - fluids

definition

Any substance which can flow with relative ease, tends to assume the shape of its container, and obeys Bernoulli's principle; a liquid, gas or plasma.

definition

A liquid (as opposed to a solid or gas).

definition

(specifically, typically in the plural) Intravenous fluids.

In the latter case, the densities of the fluids will be inversely proportional to the volumes thus displaced.

The first volume of the Histoire et memoires de l'Academie (1733) contains many original papers by him upon a great variety of physical subjects, such as the motion of fluids, the nature of colour, the notes of the trumpet, the barometer, the fall of bodies, the recoil of guns, the freezing of water, &c.

Adopting the hypothesis of two fluids, Coulomb investigated experimentally and theoretically the distribution of electricity on the surface of bodies by means of his proof plane.

In the animal kingdom, also, it is very widely distributed, being sometimes a normal and sometimes a pathological constituent of the fluids and tissues; in particular, it is present in large amount in the urine of those suffering from diabetes, and may be present in nearly all the body fluids.

In 1628 Castelli published a small work, Della misura dell' acque correnti, in which he satisfactorily explained several phenomena in the motion of fluids in rivers and canals; but he committed a great paralogism in supposing the velocity of the water proportional to the depth of the orifice below the surface of the vessel.

It was more fully developed in his Traite des fluides, published in 1744, in which he gave simple and elegant solutions of problems relating to the equilibrium and motion of fluids.

P. Hachette (1769-1834) in1816-1817published memoirs containing the results of experiments on the spouting of fluids and the discharge of vessels.

Julius Weisbach (1806-1871) also made many experimental investigations on the discharge of fluids.

A fluid, as the name implies, is a substance which flows, or is capable of flowing; water and air are the two fluids distributed most universally over the surface of the earth.

Fluids again are divided into two classes, termed a liquid and a gas, of which water and air are the chief examples.

Haematemesis is vomiting of blood, the colour of which may be altered by digestion, as is also the case in melaena, or passage of blood with the faeces, in which the blood becomes dark and tarrylooking from the action of the intestinal fluids.

Laennec, to whom we are indebted for the practice of auscultation, freely admits that the idea was suggested to him by study of Hippocrates, who, treating of the presence of morbid fluids in the thorax, gives very particular directions, by 1 " Hippocrates Cous, primus quidem ex omnibus memoria dignus, ab studio sapientiae disciplinam hanc separavit, vir et arte et facundia insignis " (Celsus, De medicina).

After death the presence of alcohol can be detected in all the body fluids.

In 1738 appeared his Hydrodynamica, in which the equilibrium, the pressure, the reaction and varied velocities of fluids are considered both theoretically and practically.

We must remember that the ocean is a continuous sheet of water of a certain depth, and the conditions of continuity which hold good for all fluids require that there should be no vacant space within it; hence if a single water particle is set in motion, the whole ocean must respond, as Varenius pointed out in 1650.

That the results do not agree even 1 " On the Cohesions of Fluids," Phil.

Not only was he the first discoverer of the rotifers, but he showed "how wonderfully nature has provided for the preservation of their species," by their tolerance of the drying-up of the water they inhabit, and the resistance afforded to the evaporation of the fluids of their bodies by the impermeability of the casing in which they then become enclosed.

Living at the time he did, when the doctrines of the humoral pathologists were carried to an extreme extent, and witnessing the ravages which disease made on the solid structures of the body, it was not surprising that he should oppose a doctrine which appeared to him to lead to a false practice and to fatal results, and adopt one which attributed more to the agency of the solids and very little to that of the fluids of the body.

In 1714 Ditton published his Discourse on the Resurrection of Jesus Christ; and The New Law of Fluids, or a Discourse concerning the Ascent of Liquids in exact Geometrical Figures, between two nearly contiguous Surfaces.

The acetate and the citrate are valuable mild diuretics in Bright's disease and in feverish conditions, and by increasing the amount of urine diminish the pathological fluids in pleuritic effusion, ascites, &c. In tubal nephritis they aid the excretion of fatty casts.

This action, at first sight somewhat obscure, is due to the extreme pupillary contraction which removes the mass of the iris from pressing upon the spaces of Fontana, through which the intraocular fluids normally make a very slow escape from the eye into its efferent lymphatics.

The quantity of substance which diffuses through unit area in one second may be taken as proportional to the difference in concentration between the fluids at that area and at another parallel area indefinitely near it.

It seems, therefore, that general laws respecting the absolute quantity and the nature of heat are more likely to be derived from elastic fluids than from other substances."

It may be noted that in a paper on the "Proportion of the gases or elastic fluids constituting the atmosphere," read by him in November 1802, the law of multiple proportions appears to be anticipated in the words - "The elements of oxygen may combine with a certain portion of nitrous gas or with twice that portion, but with no intermediate quantity," but there is reason to suspect that this sentence was added some time after the reading of the paper, which was not published till 1805.

The Stem and its' subdivisions or branches raise to the light and air the leaves and flowers, serve as channels for the passage to them of fluids from the roots, and act as reservoirs for nutritive substances.

The wonder, however, seems to be that it does not occur more frequently, seeing that fluids must pass from stock to scion, and matter elaborated in the leaves of the scion must certainly to some extent enter the stock.

Latex-tubes abound in the tissues of Lactarius, Stereum, Mycena, Fistulina, filled with white or coloured milky fluids, and Istvanffvi has shown that similar tubes with fluid or oily contents are widely spread in other Hymenomycetes.

Conduction, however, is generally understood to include diffusion of heat in fluids due to the agitation of the ultimate molecules, which is really molecular convection.

In measuring conduction of heat in fluids, it is possible to some extent to eliminate the effects of molar convection or mixing, but it would not be possible to distinguish between diffusion, or internal radiation, and conduction.

His experiments and his treatise (written before 1651, published 1663) on the equilibrium of fluids entitle him to rank with Galileo and Stevinus as one of the founders of the science of hydrodynamics.

It is also a constituent of the blood, of milk, and other animal fluids.

His published work includes Algemeene Theorie der VloeistojJen (General Theory of the Fluids, 1881).

Subsequent papers by Dulong were concerned with " New determinations of the proportions of water and the density of certain elastic fluids " (1820, with Berzelius); the property possessed by certain metals of facilitating the combination of gases (1823 with Thenard); the refracting powers of gases (1826); and the specific heats of gases (1829).

Canton (1 753, 1 754) When, for instance, a positively electrified body was found to induce upon another insulated conductor a charge of negative electricity on the side nearest to it, and a charge of positive electricity on the side farthest from it, this was explained by saying that the particles of each of the two electric fluids repelled one another but attracted those of the positive fluid.

It was then assumed that each of the two constituents of the neutral fluid had an atomic structure and that the so-called particles of one of the electric fluids, say positive, repelled similar particles with a force varying inversely as a square of the distance and attracted those of the opposite fluid according to the same law.

Frequent doses of a teaspoonful of tannin dissolved ' in water should be administered, together with strong tea and coffee and mucilaginous fluids.

Leslie's theory was afterwards treated according to Laplace's mathematical methods by James Ivory in the article on capillary action, under "Fluids, Elevation of," in the supplement to the fourth edition of the Encyclopaedia Britannica, published in 1819.

Theory Of Capillary Action When two different fluids are placed in contact, they may either diffuse into each other or remain separate.

All that we have to observe at present is that, in the cases in which the fluids do not mix of themselves, the potential energy of the system must be greater when the fluids are mixed than when they are separate.

If three fluids which do not mix are in contact with each other, the three surfaces of separation meet in a line, straight or curved.

For if in the triangle abc the side ab is taken so as to represent on a given scale the tension of the surface of contact of the fluids a and b, and if the other sides be and ca are taken so as to represent on the same scale the tensions of the surfaces between b and c and between c and a respectively, then the condition of equilibrium at 0 for the corresponding tensions R, P and Q is that the angle ROP shall be the supplement of abc, POQ of bca, and, therefore, QOR of cab.

Thus the angles at which the surfaces of separation meet are the same at all parts of the line of concourse of the three fluids.

If four fluids, a, b, c, d, meet in a point 0, and if a tetrahedron AB CD is formed so that its edge AB represents the tension of the surface of contact of the liquids a and b, BC that of b and c, and so on; then if we place this tetrahedron so that the face ABC is normal to the tangent at 0 to the line of concourse of the fluids abc, and turn it so that the edge AB is normal to the tangent plane at 0 to the surface of contact of the fluids a and b, then the other three faces of the tetrahedron will be normal to the tangents at 0 to the other three lines of concourse of the liquids, an the other five edges of the tetrahedron will be normal to the tangent planes at 0 to the other five surfaces of contact.

When a solid body is in contact with two fluids, the surface of the solid cannot alter its form, but the angle at which the surface of contact of the two fluids meets the surface of the solid depends on the values of the three surface-tensions.

If a and b are the two fluids and c the solid then the equilibrium of the tensions at the point 0 depends only on that of thin components parallel to the surface, because the surface-tensions normal to the surface are balanced by the resistance of the solid.

If the tension of the surface between the solid and one of the fluids exceeds the sum of the other two tensions, the point of contact will not be in equilibrium, but will be dragged towards the side on which the tension is greatest.

In this case the fluids must mix.

Conversely, if two fluids mix, it would seem that T'12 must exceed the mean of T 1 and T2; otherwise work would have to be expended to effect a close alternate stratification of the two bodies, such as we may suppose to constitute a first step in the process of mixture (Dupre, Theorie mecanique de la chaleur, p. 372; Kelvin, Popular Lectures, p. 53).

If the three fluids can remain in contact with one another, the sum of any two of the 3 quantities must exceed the third, and T 31 I by Neumann's rule the directions of the interfaces at the common edge must be parallel to the sides of a triangle, taken proportional to T12, T23, T31.

If the above-mentioned condition be not satisfied, the triangle is imaginary, and the three fluids cannot rest in contact, the two weaker tensions, even if acting in full concert, being incapable of balancing the strongest.