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vibration

Suddenly, I felt a vibration in my back pocket!

These two circuits are syntonized so that the closed or condenser circuit and the open or antenna circuit are adjusted to have, when separate, the same natural electrical time of vibration.

When spoken to the diaphragm vibrated, and thus set the carbon granules into vigorous vibration.

It follows that in testing iron for magnetic quality the greatest care must be exercised to guard the specimen against any accidental vibration.

That it is elastic, with narrow limits, is proved by its clear ring when struck with a hard body in circumstances permitting of free vibration.

This is generally equal to the number of waves issuing from the source per second, and therefore equal to its frequency of vibration.

If we study the source producing it we find that there is no regularity of vibration.

A musical note always arises from a source which has some regularity of vibration, and which sends equally-spaced waves into the air.

Various instruments have been devised which produce any desired note, and which are provided with methods of counting the frequency of vibration.

With this apparatus Koenig studied the effect of temperature on a standard fork of 256 frequency, and found that the frequency decreased by o 0286 of a vibration fora rise of I°, the frequency being exactly 256 at 26.2° C. Hence the frequency may be put as 256 { I - 0.000113 0-26.2)1 (From Lord Rayleigh's Theory of Sound, by permission of Macmillan & Co., Ltd.) FIG.

Imagine now that a fork with black prongs is held near the cylinder with its prongs vertical and the plane of vibration parallel to.

Another important result of the investigation was that the phase of vibration of the fork was not altered by bowing it, the amplitude alone changing.

If the fork makes exactly 32 vibrations and the wheel 8 revolutions in one pendulum beat, then the positions will be fixed, and every two seconds, the time of a complete pendulum vibration, he will see the two positions looked at flash out in succession at an interval of a second.

20) be the source at a given instant, and let its frequency of vibration, or the number of waves it sends out per second, be n.

§ 46) shows that, if there were nodissipation of energy, the vibration would increase indefinitely when the periods coincided.

But there is always leakage of energy either through friction or through wave-emission, so that the vibration only increases up to the point at which the leakage of energy balances the energy put in by the applied force.

Further, the greater the dissipation of energy the less is the prominence of the amplitude of vibration for exact coincidence over the amplitude when the periods are not quite the same, though it is still the greatest for coincidence.

The principle of forced vibration may be illustrated by a simple case.

Suppose that a mass M is controlled by some sort of spring, so that moving freely it executes harmonic vibrations given by -µx, where µx is the restoring force to the centre of vibration.

Each of them is supposed to have its own natural frequency, and to be set into vibration when the ear receives a train of waves of that frequency.

The vibration in some way arouses the sensation of the corresponding tone.

In the one, the energy of vibration of the source is measured, and the rate at which that energy decreases is observed.

The first may be illustrated by Lord Rayleigh's experiments to determine the amplitude of vibration in waves only just audible (Sound, ii.

The energy of this fork with a given amplitude of vibration could be calculated from its dimensions and elasticity, and the amplitude was observed by measuring with a microscope the line into which the image of a starch grain on the prong was drawn by the vibration.

The rate of loss of energy was calculated from the rate of dying down of the vibration.

When the plate vibrated the mirror was vibrated about the fixed edge, and the image of a reflected slit was broadened out into a band, the broadening giving the amplitude of vibration of the plate.

§ 311) gives the pressure variations in the incident waves in terms of those in the resonator, and so the pressure variation and the amplitude of vibration in the waves to be measured were determined.

As a preliminary to the investigation of the modes of vibration of certain sources of sound we shall consider the formation of " stationary waves."

- The longitudinal vibration of air in cylindrical pipes is made use of in various wind instruments.

We shall deduce the modes of vibration of the air column in a cylindrical pipe from the consideration that the air in motion within the pipe forms some part of a system of stationary waves, one train being formed by the exciter of the disturbance, and the other being formed by the reflection of the train at the end of the pipe.

The first mode of vibration gives the " fundamental tone," and the succeeding modes are termed " overtones."

We may illustrate the successive modes of vibration by using as pipe a tall cylindrical jar, and as exciter a vibrating tuning-fork held over the mouth.

The stationary wave method regards the vibration in the pipe as due to a series of waves travelling to the end and being there reflected back down the pipe.

30) maintains the vibration in a way to be discussed later, and the opening 0 makes the lower end a loop. The modes of vibration in an open organ pipe may be exhibited by means of Koenig's manometric flames (Phil.

If U 4 is the velocity of longitudinal waves along the sounder, and 1 the length of the sounder, the frequency of vibration is U 8 /2l.

excite its second mode of vibration.

The extent of vibration at different parts of the pipe was studied through a glass side wall, a stroboscopic method being used to get the position of the vapour line at a definite part of the vibration.

Elementary Theory of the Transverse Vibration of Musical Strings.

We shall then show that on certain limitations two trains of disturbance may be superposed so that stationary waves may be formed, and thence we shall deduce the modes of vibration as with pipes.

Since the nodes are always at rest we may represent the vibration of a given string by the length between any two nodes.

The various modes of vibration may also be exhibited.

A practised ear easily discerns the coexistence of these various tones when a pianoforte or violin string is thrown into vibration.

The velocity of a disturbance along such a bar, and its modes of vibration, depend therefore on the elastic properties of the material and the dimensions of the bar.

For a bar free at both ends the fundamental mode of vibration has two nodes, each 0.224 of the length from the end.

We shall not attempt to deal with the theory here but shall describe only the beautiful mode of exhibiting the regions of vibration and of rest devised by E.

The plate is then bowed at the edge and is thrown into vibration between nodal lines or curves and the sand is thrown from the moving parts or ventral segments into these lines, forming " Chladni's figures."

38, 3, to the tenth or octave of the third, the numbers of vibration in the same time being as 2 to 3 to 5.

It is easy to deduce the modes of vibration from stationary waves as in the previous cases.

When the flame is at a certain distance within the tube the air is set in vibration, and the sounding tube gives out its fundamental note continuously.

The flame appears to lengthen, but if the reflection is viewed in a vertical mirror revolving about a vertical axis or in Koenig's cube of mirrors, it is seen that the flame is really intermittent, jumping up and down once with each vibration, sometimes apparently going within the jet tube at its lowest point.

Intermittent illumination, however, with frequency equal to that of the fork shows at once that the jet is really broken up into drops, one for each vibration, and that these move over in a steady procession.

When a system is set vibrating and left to itself, the vibration gradually dies away as the energy leaks out either in the waves formed or through friction.

If the bob of the pendulum is iron, and if a coil is placed just below the centre of swing, then, if a current passes through the coil, while and only while the bob is moving towards it, the vibration is maintained.

If the current is on while the bob is receding the vibration is checked.

If it is always on it only acts as if the value of gravity were increased, and does not help to maintain or check the vibration, but merely to shorten the period.

The circuit of the electro-magnet is made and broken by the vibration of the fork in different ways - say, by a wire bridge attached to the lower prong which dips into and lifts out of two mercury cups.

Hence the attracting force does more work in the return journey than is done against it in the outgoing, and the balance is available to increase the vibration.

When the motion due to the vibration is up along the pipe from the embouchure, the air moves into the pipe from the outside, and carries the sheet-like stream in with it to the inside of the sharp edge.

Hence the stream of air does work during half the vibration and this is not abstracted during the other half, and so it goes on increasing the motion until the supply of energy in blowing is equal to the loss by friction and sound.

There will be more kinetic energy formed in the return journey and the vibration tends to grow.

But if the heat is given at the instant of greatest rarefaction, the increase of pressure lessens the difference from the undisturbed pressure, and lessens the potential energy, so that during the return less kinetic energy is formed and the vibration tends to die away.

But there is a slight delay in ignition, partly due to expulsion of incombustible gas drawn into the jet tube in the previous half period, so that the most copious supply of gas and heat is thrown into the quarter period just preceding greatest pressure, and the vibration is maintained.

The heat communication is then chiefly in the quarter vibration just preceding greatest rarefaction, and the vibration is not maintained.

If the amplitudes of vibration which thus mutually interfere are moreover equal, the effect is the total mutual destruction of the vibratory motion.

If a tuning-fork in vibration be turned round before the ear, four positions will be found in which A B it will be inaudible, owing to the mutual interference FIG.

But, after this, the first or less rapidly vibrating note will fall behind the other, and cause a diminution in the joint displacements of the particles, till, after the lapse of onesixth of a second, it will have fallen behind the other by half a vibration.

This will be followed by an increase of intensity until the lapse of another sixth of a second, when the less rapidly vibrating note will have lost another half-vibration relatively to the other, or one vibration reckoning from the original period of time, and the two component vibrations will again conspire and reproduce a maximum effect.

If one prong of each fork be furnished with a small plain mirror, and a beam of light from a luminous point be reflected successively by the two mirrors, so as to form an image on a distinct screen, when one fork alone is put in vibration, the image will move on the screen and be seen as a line of a certain length.

If both forks are in vibration, and are prefectly in tune, this line may either be increased or diminished permanently in length according to the difference of phase between the two sets of vibrations.

an hour there is not much vibration.

This is termed the vibration strength.

This equal openness to every vibration of his environment is the key to all Erasmus's acts and words, and among them to the middle attitude which he took up towards the great religious conflict of his time.

Let E be the effective elasticity of the aether; then E = pc t, where p is its density, and c the velocity of light which is 3 X 10 10 cm./sec. If = A cos" (t - x/c) is the linear vibration, the stress is E dE/dx; and the total energy, which is twice the kinetic energy Zp(d/dt) 2 dx, is 2pn2A2 per cm., which is thus equal to 1.8 ergs as above.

It thus appears that if the amplitude of vibration could be as much as 1 o_2 of the wave-length, the aether would be an excessively rare medium with very slight elasticity; and yet it would be capable of transmitting the supply of solar energy on which all terrestrial activity depends.

The word is particularly used of the cord of a bow, and of the stretched cords of gut and wire upon a musical instrument, the vibration of which.

Thus if a molecule were set into vibration at a specified time and oscillated according to the above equation during a finite period, it would not send out homogeneous vibrations.

If N be the frequency of a homogeneous vibration sent out by a molecule at rest, the apparent frequency will be N (1 v/ V), where V is the velocity of light and v is the velocity of the line of sight, taken as positive if the distance from the observer increases.

The homogeneity of vibration may also be diminished by molecular impacts, but the number of shocks in a given time depends on pressure and we may therefore expect to diminish the width of a line by diminishing the pressure.

It is not, however, obvious that the sudden change of direction in the translatory motion, which is commonly called a molecular shock, necessarily also affects the phase of vibration.

The one endeavours to determine the conditions, which are consistent with our knowledge of atomic constitution derived from other sources, and lead to systems of vibration similar to those of the actual atom.

(g) Increased pressure nearly always diminishes the frequency of vibration, but this effect is generally of a smaller order of magnitude than the widening which takes place in the other cases.

If the medium which contains the vibration is divided into a sphere equal to k times the molecular vibration outside of which the effects of these molecules may be averaged up, so that its Roy.

inductive capacity may be considered uniform and equal to K, the frequency of the vibration is increased in the ratio of the square root of 1 - le-"+3(1 - K - 1) to 2.

Here n represents an integer which is 3 if the vibration is a simple doublet, but may have a higher integer value.

- When a simple periodic force acts on a system capable of oscillatory motion the ultimate forced vibration has a period equal to that of the impressed force, but the ultimate state is only reached theoretically after an infinite time, and if meanwhile the vibrating system suffers any perturbations its free periods will at once assert themselves.

The fluorescent bands in this case appear to shift rapidly when the period of the incident vibration is altered, though the change may be small.

It would probably not be difficult to imagine a mechanical system having a number of free periods which when set into motion by a forced vibration shows a corresponding effect.

If the forced vibration is suddenly stopped, the free periods will appear but not necessarily with the same intensity when the period of the original forced vibration is altered.

By the vibration experiment we obtain the value of the product of the magnetic moment (M) of the magnet into the horizontal component (H), while by the deflexion experiment we can deduce the value of the ratio of M to H, and hence the two combined give both M and H.

In the case of the Kew pattern unifilar the same magnet that is used for the declination is usually employed for determining H, and for the purposes of the vibration experiment it is mounted as for the observation of the magnetic meridian.

The time of vibration is obtained by means of a chronometer, using the eye-and-ear method.

The magnet K used in the vibration experiment is supported on a carriage L which can slide along the graduated bar D.

Mag., 1904 [6], 7, p. 113.) In the case of the vibration experiment correction terms have to be introduced to allow for the temperature of the magnet, for the inductive effect of the earth's field, which slightly increases the magnetic moment of the magnet, and for the torsion of the suspension fibre, as well as the rate of the chronometer.

If the temperature of the magnet were always exactly the same in both the vibration and FIG 2.

They are also fitted with different forms of suspension in which the compass is mounted to obviate the mechanical disturbance of the card caused by the vibration of the hull in ships driven by powerful engines.

The introduction of powerful engines causing serious vibration to compass cards of the admiralty type, coupled with the prevailing desire for larger cards, the deviation of which could also be more conveniently compensated, led to the gradual introduction of the Thomson compass.

4, which, according to the kinetic theory, is an indication that an important fraction of the energy absorbed is devoted to rotation or vibration.

The fact that a comparatively brittle material like concrete can be subjected not only to heavy loads but also to the jar and vibration from the blows of a heavy pile ram makes it appear as if its nature and properties had been changed by the steel reinforcement.

It is now generally accepted that these sounds are produced by the vibration of the webs of the outer tail-feathers, the webs of which are modified.

Probably the most successful one has been a rotary engine invented by Mr Arthur Rigg.1 In this engine the stroke, and therefore the amount of water used, can be varied either by hand or by a governor while it is running; the speed can also be varied, very high rates, as much as 600 revolutions a minute, being attainable without the question of shock or vibration becoming troublesome.

Weber's hypothesis of electric atoms, capable of diffusing through metallic bodies and conductors of electricity, but capable of vibration only in non-conductors, it is possible that the ultimate mechanism of conduction may be reduced in all cases to that of diffusion in metallic bodies or internal radiation in dielectrics.

Although by compounding corresponding portions of the diagrams given by instruments of this type, it is possible to determine the range and direction of the movement of which they are the resolved parts, their chief value is that they enable us to measure with ease the extent of any vibration, half of which is called its amplitude, and the time taken to make any complete back-and-forth movement, or its period.

The currents induced in the coil are led to a dead-beat D'Arsonval galvanometer having the same natural period of vibration as the pendulum.

For Diatomic Or Compound Gases Clerk Maxwell Supposed That The Molecule Would Also Possess Energy Of Rotation, And Endeavoured To Prove That In This Case The Energy Would Be Equally Divided Between The Six Degrees Of Freedom, Three Of Translation And Three Of Rotation, If The Molecule Were Regarded As A Rigid Body Incapable Of Vibration Energy.

In 1879 Maxwell Considered It One Of The Greatest Difficulties Which The Kinetic Theory Had Yet Encountered, That In Spite Of The Many Other Degrees Of Freedom Of Vibration Revealed By The Spectroscope, The Experimental Value Of The Ratio S/S Was 1.40 For So Many Gases, Instead Of Being Less Than 4/3.

Since Much Smaller Values Are Found For More Complex Molecules, We May Suppose That, In These Cases, The Energy Of Rotation Of A Polyatomic Molecule May Be Greater Than Its Energy Of Translation, Or Else That Heat Is Expended In Splitting Up Molecular Aggregates, And Increasing Energy Of Vibration.

It Is Not At All Clear, However, That Energy Of Vibration Should Bear A Constant Ratio To That Of Translation, Although This Would Probably Be The Case For Rotation.

For The Simpler Gases, Which Are Highly Diathermanous And Radiate Badly Even At High Temperature, The Energy Of Vibration Is Probably Very Small, Except Under The Special Conditions Which Produce Luminosity In Flames And Electric Discharges.

The Energy Of Vibration May Be Appreciable At Ordinary Temperatures, And Would Probably Increase More Rapidly Than That Of Translation With Rise Of Temperature, Especially Near A Point Of Dissociation.

The type of motion represented by (6) is of fundamental importance in the theory of vibrations (~ 23); it is ~- called a simple-harmonic or (shortly) a simple vibration.

If we imagine a point Q to describe a circle of radius a _________________ with the angular velocity ~, its A - 0 P orthogonal projection P on a fixed diameter AA will execute a vibration of this character.

which represents a vibration of continually increasing amplitude, Since the equation (12) is in practice generally only an approxi.

To obtain the complete solution of (II) we must of course superpose the free vibration (6) with its arbitrary constants in order to obtain a complete representation of the most general motion consequent on arbitrary initial conditions.

If the point of suspension have an imposed simple vibration f = a cos at in a horizontal line, the equation of small motion of the bob is mx= mg-l-,

The difference of phase of the forced vibration in the two cases is illustrated and explained in the annexed fig.

We have seen that a true simple-harmonic vibration may be regarded as the orthogonal projection of uniform circular motion; it was pointed out by P. G.

The body now passes once (at most) through its equilibrium position, and the vibration is therefore styled aperiodic.

Hence the phase of the vibration lags behind that of the force by the amount s~, which lies between 0 and 1/2nr or between 1/2ir and Ir, according as e12 ~u.

For a complete solution of (34) we must of course superpose the free vibration (30); but owing to the factor ehlt the influence of the initial conditions gradually disappears.

Further, on examining the small variation in i/i, it appears that in a slightly disturbed slow precession the motion of any point of the axis consists of a rapid circular vibration superposed on the steady precession, so that the resultant path has a trochoidal character.

In a slightly disturbed rapid precession the superposed vibration is elliptic-harmonic, with a period equal to that of the precession itself.

This solution, taken by itself, represents a motion in which each particle of the system (since its displacements parallel to Cartesian co-ordinate axes are linear functions of the qs) executes a simple vibration of period 21r/u.

\M vibration of this character is called a normal mode ~ of vibration of the system; the number n of such modes is equal to that of the degrees of freedom ~ \ possessed by the system.

In the normal mode corresponding to the former root, M swings almost like the bob of a simple pendulum of length a, being comparatively uninfluenced by the presence of m, whilst m executes a forced vibration (~I2) of the corresponding period.

The vibration then appears to be transferret alternately from m to M at regular intervals.

are called the normal co-ordinates of the system; in a normal mode of vibration one of these varies alone.

Also that if the constrained mode differs little from a normal mode of free vibration (e.g.

Every particle of the system executes in general a simple vibration of the imposed period 27r/il, and all the particles pass simultaneously through their equilibrium positions.

If we omit the gyrostatic terms, and write qr = Cre, we finc~, for a free vibration, (aj,1~2 + birX + Cm) C~ + (asrX2 + birX + Cm) C2 +

The n formulae of this type represent a normal mode of free vibration; the individual particles revolve as a rule in elliptic orbits which gradually contract according to the law indicated by the exponential factor.

In a forced vibration.

Hence, unless there be some reason to the contrary, each piece of a machine should be balanced on its axis of rotation; otherwise the centrifugal force will cause strains, vibration and increased friction, and a tendency of the shafts to jump out of their bearings.

Macalpine, A Solution of the Vibration Problem (ibid., 1901).

Dunkerley (On the Whirling and Vibration of Shafts, Phil.

The insular position of England, combined with the nature of the English people, has allowed us to feel the vibration of European movements later and with less of shock than any of the continental nations.

The type bed travels with a reciprocating motion upon rollers or runners made of steel, the bed being driven by a simple crank motion, starting and stopping without much noise or vibration.

He explained accurately the mechanism of the bones of the ear, and he discussed the physiological action of the cochlea on the principles of sympathetic vibration.

These earthquake shocks have two distinct characteristics, a slight vibration, sometimes almost imperceptible, called a temblor, generally occurring at frequent intervals, and a violent horizontal or rotary vibration, or motion, also repeated at frequent intervals, called a terremoto, which is caused by a fracture or displacement of the earth's strata at some particular point, and often results in considerable damage.

Now that the length of a division has been estimated a priori, it is perhaps preferable to reverse Plateau's calculation, and to exhibit the frequency of vibration in terms of the other data of the problem.

Magnus showed that the most important part of the effect is due to the forced vibration of that side of the vessel which contains the orifice, and that but little of it is propagated through the air.

According to theory, there would be no well-defined lower limit; on the other side, the external vibration cannot be efficient if it tends to produce divisions whose length is less than the circumference of the jet.

When the resolution is effected in a perfectly periodic manner, each drop is in the same phase of its vibration as it passes through a given point of space; and thence arises the remarkable appearance of alternate swellings and contractions described by Savart.

The interval from one swelling to the next is the space described by the drop during one complete vibration,and is therefore (as Plateau shows) proportional ceteris paribus to the square root of the head.

The time of vibration is of course itself a function of the nature of the fluid and of the size of the drop. By the method of dimensions alone it may be seen that the time of infinitely small vibrations varies directly as the square root of the mass of the sphere and inversely as the square root of the capillary tension; and it may be proved that its expression is - V C?

Regular vibration has, however, the effect of postponing the collisions and consequent scattering of the drops, and in the case of a direction of motion less nearly vertical, may prevent them altogether.

The second obstacle is surmounted by the aid of the stroboscopic method of observation, the light being intermittent in the period of vibration, so that practically only one phase is seen.

The principal vibration, in which the section becomes elliptical, corresponds to n = 2.

Since the phase of vibration depends upon the time elapsed, it is always the same at the same point in space, and thus the motion is steady in the hydrodynamical sense, and the boundary of the jet is a fixed surface.

A formula, similar to (5), may be given for the frequencies of vibration of a spherical mass of liquid under capillary force.

As will be seen from these figures, the wing during its vibration sweeps through a comparatively very large space.

If the wing was inelastic, every part of it would reverse at precisely the same moment, and its vibration would be characterized by pauses or dead points at the end of the down and up strokes which would be fatal to it as a flying organ.

He, in fact, endeavours to prove that a bird wedges itself forward upon the air by the perpendicular vibration of its wings, the wings during their action forming a wedge, the base of which (c b e) is directed towards the head of the bird, the apex (a f) being directed towards the tail (d).

If a rigid rod, or a wing with a rigid anterior margin, be made to vibrate, the vibration is characterized by an unequal jerky motion, at the end of the down and up strokes, which contrasts strangely with the smooth, steady fanning movement peculiar to natural wings.

It must not only be strong enough to sustain all possible vertical loads, but it must be sufficiently rigid to resist without deformation or weakening all lateral disturbing forces, the principal of which are the pressure of wind, the possible sway of moving crowds or moving machinery, and the vibration of the earth from the passage of loaded vans and trolleys, and slight earthquakes which at times visit almost all localities.

In American practice the use of steel in buildings of ten or more storeys, or in manufacturing plant where the floor loads are heavy and frequently " live " in the sense of causing vibration, has led to more careful specifications as to the quality of materials and character of workmanship, and it is the custom of the leading architects to have the structural frame inspected and tested during manufacture at the foundries, rolling-mills and shops by a firm of engineers making a speciality of such inspections.

In addition to his philosophical work, AzaIs studied music under his father, Pierre Hyacinthe AzaIs (1743-1796), professor of music at Soreze and Toulouse, and composer of sacred music in the style of Gossec. He wrote for the Revue musicale a series of articles entitled Acoustique fondamentale (1831), containing an ingenious, but now exploded, theory of the vibration of the air.

When a system vibrating in a free period of its own encounters, say through the medium of an enveloping aether, a second system having a different free period, and sets it in vibration, the amplitude of the second vibration is inconsiderable, except when the periods approach equality.

In such a case the two systems must be regarded as a single more complex one, the absorbed vibration becomes large, though remaining always finite, and the transmitted vibration undergoes a remarkable change in its period.

The line n shows the factor by which the index of refraction of the transmitted vibration is multiplied, and the curve p the intensity of the absorbed vibration for that wave-length.

back the coloured ribbon of the spectrum upon itself, but just where this is done all its light will be robbed to maintain the absorbing system in vibration.

Weisbach also shows that if Gy 2 is the moment of inertia of the beam, the time, t, of a vibration of the balance is 2 (P+Q) (I' a 2) G y2 t = r gt2 (P+Q) a+Gs) This shows that the time of a vibration increases as P, Q and / increase, and as a and s diminish.

If the knife - edges be placed so that and h 2 are below the lines x i y i and x2y2 respectively, the arrangement will favour the " vibration " principle, and is suited to act with and assist a " vibrating " steelyard.

To deaden the vibration of the springs after a load has been placed on the platform, and thus to enable the weights and values of the goods to be read rapidly, the piston of a glycerin cylinder is attached to the end of the lever which pulls upon the hook of the horizontal bar and is worked by it in the glycerin.

This can be accomplished by attaching balance-weights to the pulley until it will remain stationary in all positions, when its shaft rests on two horizontal knife-edges in the same horizontal plane, or, preferably, the pulley and shaft may be supported on bearings resting on springs, and balanced by attached masses until there is no perceptible vibration of the springs at the highest speed of rotation.

Each consists in essence of a tightly stretched membrane or drum which is thrown into a state of rapid vibration by a powerful muscle attached to its inner surface and passing thence downwards to the floor of the thoracic cavity.

Now Fresnel's formulae were obtained by assuming that the incident, reflected and refracted vibrations are in the same or opposite phases at the interface of the media, and since there is no real factor that converts cos T into cos (T+p), he inferred that the occurrence of imaginary expressions for the coefficients of vibration denotes a change of phase other than 7r, this being represented by a change of sign.

One method consists in finding directly the elliptic constants of the vibration by means of a quarterwave plate and an analyser; but the more usual plan is to measure the relative retardation of two rectangular components of the stream by a Babinet's compensator.

It is most important the stand should be free of vibration.

Suddenly, I felt a vibration in my back pocket!

air cushion wall is of low impedance and causes reflection of ground vibration on the upstream side.

amplitude of vibration of the system at resonance is observed to be 14 mm.

audio-frequency noise and vibration performance is important, and hence the engineer needs to design for low-noise products.

behave according to a higher mode of vibration.

This vibration may be experienced by someone who may have latent clairvoyance and occasionally ' seen ' as a ghost.

This reduced vibration, the limiting factor with parallel twins and made for an efficient combustion chamber.

damps vibration and gives you extra cush for big landings.

damping ratio of a structure, the quicker the decay of its free vibration.

dampen excessive belt vibration.

The motor holder consists of a rubber part at the center to act as a vibration damper.

Back problems, cement dermatitis, vibration white finger and deafness can ruin people's lives and force them out of their chosen profession.

The locations on the board at which zero vibration displacement occurs are called nodes, and the maximum displacement amplitudes occur at the antinodes.

divider systems for protecting against impact, vibration or shock.

frequency of the vibration of the folds.

A single string could seem to be any one of several particles depending on its state of vibration, particularly its vibrational frequency.

A technique for calculating the time domain averages of the vibration of the individual planet gears and sun gear in an epicyclic gearbox.

high frequencyndicate that human are less sensitive to higher frequencies of vibration.

The building block approach is used to account for the effect of foundations on systems designed to provide vibration isolation.

Our services include: Measurement of hand arm vibration magnitudes.

We used a heavy paving mallet to put a vibration impulse into the floor with simultaneous measurements being made in both buildings.

mode of vibration of a string yields an electron.

Engine noise is well muffled and vibration can only really be felt through the gearstick.

In the case of normal mode vibration derived from a relaxation oscillation, we need low-frequency tuning of the attached oscillator.

This, in turn, causes vibration of tiny bones in the middle ear (the ear ossicles ).

Depending on the test specification, vibration tests may be carried out on a single axis or three mutually perpendicular axes.

Using an optical technique for displacement measurement enables remote sensing of vibration.

The engine unit is exceptionally rigid, with vibration and noise reduced as much as possible.

rumblesound quality is superb, tho the vibration of rumbling bass may not be to everyone's taste.

scaler tip during vibration analysis.

sceptref the old writers says: " He who understands the Principle of Vibration has grasped the scepter of power " .

self-adhesive backing of the vibration damping sheet.

Engine noise is minimal with only a slight and quite soporific vibration.

tapered roller and spherical roller bearings subject to shock or vibration loads.

acoustic emission transducers for the vibration monitoring of bearings at low speeds.

These clamps are important as they suppress coil vibration transmitted from the engine.

twirling cane, mouth opens and closes, vibration causes the toy to move around on smooth surfaces.

undamped vibration of any linear structure, for example by Finite Element methods.

undamped system to complete one cycle of free vibration is the natural period of vibration of the system.

BS 6472 states: ' Within residential areas people exhibit wide variations of vibration tolerance.

The Vortex dampens the vibration caused by the rapidly spinning motors in the hard drive, reducing noise and shock.

vibration induced by a sudden rotation of the motor hub.

The density relieving spheres within CMM dramatically damp vibration, offering a pure, soft feel.

Hand-arm vibration: The Control of Vibration at Work Regulations 2005.

The piezoelectric actuator can generate the bending moment to suppress unwanted flexural vibration induced by a sudden rotation of the motor hub.

vibration absorber system was shown to be potentially relevant in respect of floor response in Base Isolated structures.

vibration dampers.

vibration isolation.

vibration magnitudes.

vibration syndrome; Occupational stress; Noise induced hearing loss.

Aimed at employers, this leaflet outlines the ways that hand-arm vibration can be controlled.

Contents: Introduction; The health effects of whole-body vibration; Who is at risk?

Its ergonomic design puts silky smooth multi-speed vibration right at the tip of your fingers.

What I DO notice is that roads with a coarse, or damaged, top dressing can induce pronounced high-frequency vibration.

Some people also may feel uplifted in their vibration just by holding the wand in their hand.

In that case a sine wave type vibration did show up on the photographs.

The disturbance, consisting of transverse vibrations, is propagated outwards in all directions from the centre; and, in consequence of the symmetry, the direction of vibration in any ray lies in the plane containing the ray and the axis of symmetry; that is to say, the direction of vibration in the scattered or diffracted ray makes with the direction of vibration in the incident or primary ray the least possible angle.

Suppose, for distinctness of statement, that the primary ray is vertical, and that the plane of vibration is that of the meridian.

If the primary ray is unpolarized, the light scattered north and south is entirely due to that component which vibrates east and west, and is therefore perfectly polarized, the direction of its vibration being also east and west.

Similarly any other ray scattered horizontally is perfectly polarized, and the vibration is performed in the horizontal plane.

Let the particle be at the origin of coordinates, and let the expression for the primary vibration be =sin (nt - kx).

Accordingly, if E be the energy of the primary wave, dE 87-2n (D' - D) 2 T2 E dx 3 D2%4 ' whence E = Eoe-hx (II) where h = 8?r 2 n (D' - D)2T2 3 D2 x 4, (12) If we had a sufficiently complete expression for the scattered light, we might investigate (12) somewhat more directly by considering the resultant of the primary vibration and of the secondary vibrations which travel in the same direction.

be this stratum, and 0 the point where the vibration is to be estimated.

We learn that the light dispersed in the direction of primary vibration is not only of higher order in the difference of optical quality, but is also of order k 2 c 2 in comparison with that dispersed in other directions, where c is the radius of the sphere, and k=21r/X as before.

It is precisely defined by a vibration number recording the frequency of the pulsations of a tense string, a column of air, or other vibrator, in a second of time.

In Great Britain and America the complete vibration to and fro (swing both ways of a pendulum) is taken as the unit; elsewhere the vibration in one direction only (swing one way of the pendulum).

The vibration number stated in the edict establishing the Diapason Normal is 870 (435), which for comparison will be here adhered to.

The lower vibration number is justified by due consideration of the three divisions of the male voice, bass, tenor and alto, as given by Praetorius, whose Cammerton very closely corresponds with Bernhardt Schmidt's Durham organ, 1663-1668, the original pitch of which has been proved by Professor Armes to have been a 1 474.1.

Forks intended for this vibration number, stamped "Philharmonic," were sold as late as 1846.

In 1896 the Philharmonic Society decided upon a performing pitch, ostensibly at 68Ã‚° Fahr., of a' 439; and in 1899 Messrs Broadwood made a successful effort to get this vibration number accepted by their competitors in Great Britain.

The coefficient of this rise is equivalent to half a vibration (o.5) per degree Fahr.

Continuing his inquiries for the next year or two, he was able to discover the progressive propagation of electromagnetic action through space, to measure the length and velocity of electromagnetic waves, and to show that in the transverse nature of their vibration and their susceptibility to reflection, refraction and polarization they are in complete correspondence with the waves of light and heat.

If the rates of vibration of the two tuning-forks at the two stations could be maintained precisely the same, the two arms would rotate in synchronism, but as this uniform vibration cannot be exactly A / 4 3/ Line /‘ --- /4 -- ?

preserved for any length of time, a means is provided whereby the rate of vibration of either of the forks can be slowed down, so as to retard the rate of rotation of one or other of the arms. This is effected by means of " correcting " segments, of which there are six sets containing three each.

Should the rotating arms fail to pass over these correcting segments at their synchronous positions, correcting currents pass to a relay which cuts off momentarily the current actuating the tuning-fork, thereby altering the rate of vibration of the latter until the arms once more run together uniformly.

In the latter case, which is the standard practice, mechanical vibration of the siphon is substituted in the place of electrification of the ink, so as to eliminate the effect of atmospheric conditions which frequently caused discontinuity in the flow of ink.

Such a pendulum can be set in vigorous vibration even by feeble puffs of air directed against it, provided these are administered exactly in time with the natural period of vibration of the pendulum.

These two circuits are syntonized so that the closed or condenser circuit and the open or antenna circuit are adjusted to have, when separate, the same natural electrical time of vibration.

circuit at each vibration, thus transmitting as many electric pulses through the circuit as there were vibrations in the sound.

When spoken to the diaphragm vibrated, and thus set the carbon granules into vigorous vibration.

All tadpoles are provided with more or less distinct lines of muciferous sensory crypts or canals, which stand in immediate relation to the nerve branches and are regarded as organs of a special sense possessed by aquatic vertebrates, feeling, in its broadest sense, having been admitted as their possible use, and the function of determining waves of vibration in the aqueous medium having been suggested.

In taffrail logs, the movement of the line owing to its length becomes spasmodic and jerky, increasing the vibration and friction; to obviate this a governor or fly-wheel is introduced, the hook of the tow line K (fig.