They got a dose of radiation poisoning.
We've gotta treat as many people as we can who are suffering from radiation poisoning.
The radiation treatments we found in the feds' storage facility worked.
All these methods warm chiefly by means of convected heat, the amount of true radiation from the pipes being small.
The object of all heating apparatus is the transference of heat from the fire to the various parts of the building it is intended to warm, and this transfer may be effected by radiation, by conduction or by convection.
Even so, you want to be wary of the spread of radiation in the aquifers.
She'd traveled nonstop, sticking to narrow country roads and the forest to avoid both people and zones marked as having any sort of radiation fallout from the nuke strikes.
We didn't test her for radiation yet, Kelli added.
Yet Christian orthodoxy, which itself has, all but uniformly, understood this passage of the spiritual radiation throughout the world of the Word before His incarnation, has been aided towards such breadth as to the past by the Johannine outlook into the future.
If heat passes "of itself" from a higher to a lower temperature by conduction, convection or radiation, the transfer cannot be reversed without an expenditure of work.
Edmond Becquerel was associated with his father in much of his work, but he himself paid special attention to the study of light, investigating the photochemical effects and spectroscopic characters of solar radiation and the electric light, and the phenomena of phosphorescence, particularly as displayed by the sulphides and by compounds of uranium.
In the course of time the centres of radiation of all these groups had imposed upon them ornate rose dei venti, or windroses, such as may still be seen upon our compass-cards.
The most fundamental experimental confirmation that the theory of the aether has received on the optical side in recent years has been the verification of Maxwell's proposition that radiation exerts mechanical force on a material system, on which it falls, which may be represented in all cases as the resultant of pressures operating along the rays, and of intensity equal at each point of free space to the density of radiant energy.
An open fire acts by radiation; it warms the air in a room by first warming the walls, floor, ceiling and articles in the room, and these in turn warm the air.
Even if the sun were made of one mass of fuel as efficient as coal, that mass must be entirely expended in a few thousand years if the present rate of radiation was to be sustained.
The above statements, though correct as far as they go, are an imperfect account of the nature of the radiation from a coupled antenna, but a mathematical treatment is required for a fuller explanation.
12039 of 1896) brought forward the idea of focusing a beam of electric radiation for telegraphic purposes on a distant station by means of parabolic mirrors, and tried this method successfully on Salisbury Plain up to a distance of about a couple of miles.
Again, the temperature of the air is affected by radiation from the soil; and radiation differs in various soils.
Among his articles may be mentioned those which he wrote for the ninth edition of this Encyclopaedia on Light, Mechanics, Quaternions, Radiation and Thermodynamics, besides the biographical notices of Hamilton and Clerk Maxwell.
Its foreshore consists of a great expanse of firm, bright sands, and the mildness of its winter climate is attributed to the radiation of heat from them.
The angle which the earth's axis makes with the plane in which the planet revolves round the sun determines the varying seasonal distribution of solar radiation over the surface and the mathematical zones of climate.
A problem of great importance in connexion with electric wave telegraphy is that of limiting the radiation to certain directions.
At sunset, too, after a warm day, if the air is still, the cooling of the earth by radiation cools the lower layers, and sound carries excellently over a level surface.
In the winter similar consequences ensue, in a negative direction, from the prolonged loss of heat by radiation in the long and clear nights - an effect which is intensified wherever the surface is covered with snow, or the air little charged with vapour.
Solar radiation warms the tropical more than the polar waters, but, assuming equal salinity, this cause would not account for a difference of level of more than 20 ft.
He was distinguished as the discoverer of radioactivity, having found in 1896 that uranium at ordinary temperatures emits an invisible radiation which in many respects resembles Rntgen rays, and can affect a photographic plate after passing through thin plates of metal.
With the experience thus gained in manipulating the vacuum, the achievement of thoroughly verifying the pressure of radiation on both opaque and transparent bodies, in accordance with Clerk Maxwell's formula, has been effected (Physical Review, 1901, and later papers) by E.
The warming of the ocean is due practically to solar radiation alone; such heat as may be received from the interior of the earth can only produce a small effect and is fairly uniformly distributed.
This phenomenon he explained as a "repulsion from radiation," and he expressed his discovery in the statement that in a vessel exhausted of air a body tends to move away from another body hotter than itself.
Taking into account the heat absorbed by the box and the metal, Rumford calculated that the heat developed was sufficient to raise 26.58 lb of water from the freezing to the boiling point, and in this calculation the heat lost by radiation and conduction was neglected.
In all cases of wave motion the wave-length is connected with the velocity of propagation of the radiation by the relation v=nX, where n is the frequency of the oscillations and X is the wave-length.
If we suppose that the aether differs from ordinary matter in degree but not in kind, we can obtain some idea of its quality from a knowledge of the velocity of radiation and of its possible intensity near the sun, in a manner applied long ago by Lord Kelvin (Trans.
If c is the velocity of radiation in free space and, u the refractive index of a transparent body, V= c/ï¿½; thus it is the expression c2 fï¿½ 2 (u'dx-}-v'dy+w'dz) that is to be integrable explicitly, where now (u',v',w') is what is added to V owing to the velocity (u,v,w) of the medium.
of Strassburg by rail, and at the radiation of lines to Luxemburg, Coblenz and Noveant, on the French frontier (102 m.
Poynting has separated the two effects experimentally on the principle that the radiometer pressure acts along the normal, while the radiation pressure acts along the ray which may be directed obliquely.
We have not the slightest reason to think that the radiation from the sun is measurably weaker now than it was a couple of thousand years ago, yet it can be shown that, if the sun were merely radiating heat as simply a hot body, then it would cool some degrees every year, and must have cooled many thousands of degrees within the time covered by historical records.
was whether the mechanical impulsion was a direct effect of the light, or whether the radiation only set up internal stresses, acting in and through the residual air, between the vanes and the walls of the enclosure.
The radiations interfere in an optical sense of the word, and in some directions reinforce each other and in other directions neutralize each other, so making the resultant radiation greater in some directions than others.
Antenna has several important parameters: resonant frequency,gain, impedance, aperture or radiation pattern, efficiency and bandwidth, polarization.
Great irregular variations in radiation and convection sometimes produce a remarkably abrupt change of temperature at a certain depth in calm water.
Poynting may also be mentioned, in which the tangential component of the thrust of obliquely incident radiation is separately put in evidence, by the torsion produced in an arrangement which is not sensitive to the normal component or to the radiometer-pressure of the residual gas.
Hertz had shown that the electric radiation from an oscillator See J.
Depending on the fact that the electrical conductivity of a metallic conductor is decreased by heat, it consists of two strips of platinum, arranged to form the two arms of a Wheatstone bridge; one strip being exposed to a source of radiation from which the other is shielded, the heat causes a change in the resistance of one arm, the balance of the bridge is destroyed, and a deflection is marked on the galvanometer.
As, however, our terrestrial optical apparatus is now all in motion along with the matter, we must dealt .with the rays relative to the moving system, and to these also Fermat's principle clearly applies; thus V+ (lu'--mv'-Fnw') is here the velocity of radiation in the direction of the ray, but relative to the moving material system.
In the Fery radiation pyrometer this difficulty is obviated, as the instrument may be placed at a considerable distance from the furnace.
By thus controlling and partially eliminating the aggregate gas-effect, they succeeded in making a small radiometer, horizontally suspended, into a delicate and reliable measurer of the intensity of the radiation incident on it.
According to modern measurements the solar radiation imparts almost 3 grammecalories of energy per minute per square centimetre at the distance of the earth, which is about Iï¿½3 X io s ergs per sec. per cm.
This reflection is suggested by the following articles: Aether; Molecule; Capillary Action; Diffusion; Radiation, Theory Of; and others.
The penetration of warmth from the surface is effected by direct radiation, and by convection by particles rendered dense by evaporation increasing salinity.
Hence the paths and times of passage of all rays relative to the material system will not be altered by a uniform motion of the system, provided the velocity of radiation relative to the system, in material of index ï¿½, is diminished by ï¿½ -2 times the velocity of the system in the direction of the radiation, that is, provided the absolute velocity of radiation is increased by 1-ï¿½2 times the velocity of the material system; this involves that the free aether for which, u is unity shall remain at rest.
When the rays of the sun or a candle, or dark radiation from a warm body, are incident on the vanes, the dark side of each vane is repelled more than the bright side, and thus the vanes are set into rotation with accelerated speed, which becomes uniform when the forces produced by the radiation are balanced by the friction of the pivot and of the residual air in the globe.
On the other hand, if the effects arose from balanced stresses set up inside the globe by the radiation, the effects on the vanes and on the case would be of the nature of action and reaction, so that the establishment of motion of the vanes in one direction would involve impulsion of the case in the opposite direction; but when the motion became steady there would no longer be any torque either on the vanes or on the case, and the latter would therefore come back to its previous position of equilibrium; finally, when the light was turned off, the decay of the motion of the vanes would involve impulsion of the case in the direction of their motion until the moment of the restoring torque arising from the suspension of the case had absorbed the angular momentum in the system.
The crucible was surrounded with a bad conductor of heat to minimize loss by radiation.
Fortunately, the earth's atmosphere absorbs this form of radiation.
They present to the fierce play of the sun almost a level surface, so that during the day that surface becomes intensely heated and at night gives off its heat by radiation.
This loop hung in a very strong magnetic field, and when one junction was heated by radiation and convection from the heating wire the loop was 18 See R.
What is required is some means for localizing and directing a beam of radiation.
Theory Of Radiation >>
The loose material may, and in an arid region does, consist only of portions of the higher parts of the surface detached by the expansion and contraction produced by heating and cooling due to radiation.
The amount of the sun's heat has been estimated, but we receive on the earth less than one two-thousand-millionth part of the whole radiation.
It would take 20 tons of coal a day burned on each square foot of the sun's surface to supply the daily radiation.
The connexion that seemed to be first established was between variations in the quantity of water transported from the tropical to the sub-polar Atlantic and variations in the intensit y of solar radiation.
Helland-Hansen and Nansen showed later that it was improbable that variations in the northerly drift of Atlantic water could be traced directly to variations in the quantity of heat received by the sea from solar radiation.
Several modifications were proposed, in one of which, intended for the heating of non-conducting substances, the electrodes were passed horizontally through perforations in the upper part of the crucible walls, and the charge in the lower part of the crucible was heated by radiation.
It had been remarked at various times, amongst others by Fresnel, that bodies delicately suspended within a partial vacuum are subject to apparent repulsion by radiation.
The name radiometer arose from an idea that the final steady speed of rotation might be utilized as a rough measure of the intensity of the exciting radiation.
The answer to this was found experimentally by Arthur Schuster, who suspended the whole instrument in delicate equilibrium, and observed the effect of introducing the radiation.
Hull; some months earlier Lebedew had published in the Annalen der Physik a verification for metallic vanes so thin as to avoid the gasaction, by preventing the production of sensible difference of temperature between the two faces by the incident radiation.
This theory secures that the times of passage of the rays shall be independent of the motion of the system, only up to the first order of the ratio of its velocity to that of radiation.
See also MOLECULE, ELECTRICITY, LIGHT and RADIATION.
The eldest, Lawrence Parsons, 4th earl of Rosse, and Baron Oxmantown, born on the 17th of November 1840, succeeded to the title on his father's death, and made many investigations on the heavenly bodies, particularly on the radiation of the moon and related physical questions; the youngest, the Hon.
He especially devoted himself to investigations of the radiation of heat from the sun and its absorption by the earth's atmosphere, and to that end devised various delicate methods and instruments, including his electric compensation pyrheliometer, invented in 1893, and apparatus for obtaining a photographic representation of the infra-red spectrum (1895).
Knight, made under the direction of Professor Osborn.) Laws of Local Adaptive Radiation and Polyphyletic Evolution, illustrated by two Upper Miocene Horses of the Plains Region of North America.
Starting with the stem forms the descendants of which have passed through either persistent or changed habitats, we reach the underlying idea of the branching law of Lamarck or the law of divergence of Darwin, and find it perhaps most clearly expressed in the words "adaptive radiation" (Osborn), which convey the idea of radii in many directions.
We observe the contemporaneous and largely independent radiations of the hoofed animals in South America, in Africa and in the great ancient continent comprising Europe, Asia and North America; we observe the Cretaceous radiation of hoofed animals in the northern hemisphere, followed by a second radiation of hoofed animals in the same region, in some cases one surviving spur of an old radiation becoming the centre of a new one.
As a rule, the larger the geographic theatre the grander the radiation.
Successive discoveries have revealed certain grand centres, such as (1) the marsupial radiation of Australia, (2) the littleknown Cretaceous radiation of placental mammals in the northern hemisphere, which was probably connected in part with the peopling of South America, (3) the Tertiary placental radiation in the northern hemisphere, partly connected with Africa, (4) the main Tertiary radiation in South America.
Theory of Radiation.
- The general recognition of spectrum analysis as a method of physical and chemical research occurred simultaneously with the theoretical foundation of the connexion between radiation and absorption.
This result, which, accepting the possibility of having an absolutely opaque enclosure of uniform temperature, was clearly proved by Balfour Stewart for the total radiation, was further extended by Kirchhoff, who applied it (though not with mathematical rigidity as is sometimes supposed) to the separate wave-lengths.
All Kirchhoff's further conclusions are based on the assumption that the radiation transmitted through a partially transparent body can be expressed in term,s.
of two independent factors (i) an absorption of the incident radiation, and (2) the radiation of the absorbing medium, which takes place equally in' all directions.
It is assumed further that the absorption is proportional to the incident radiation and (at any rate approximately) independent of the temperature, while the radiation is assumed to be a function of the temperature 6 Phil.
This division into absorption and radiation is to some extent artificial and will have to be revised when the.
p henomena of radiation are placed on a mechanical basis.
For our present purpose it is only necessary to point out the difficulty involved in the assumption that the radiation of a body is independent of the temperature of the enclosure.
When the molecule is losing energy the intensity of each kind of radiation depends principally on the rapidity with which it can be renewed by molecular impacts.
Radiation is a molecular process, and we can speak of the radiation of a molecule but not of its temperature.
When we are trying to bring radiation into connexion with temperature, we must therefore take a sufficiently large group of molecules and compare their average energies with the average radiation.
The question arises whether in a vacuum discharge, in which only a comparatively small proportion of the molecules are affected, we are to take the average radiation of the affected portion or include the whole lot of molecules, which at any moment are not concerned in the discharge at all.
We must now inquire a little more closely into the mechanical conception of radiation.
The electrons responsible for the radiation are probably few and not directly involved in the structure of the atom, which according to the view at present in favour, is itself made up of electrons.
As there is undoubtedly a connexion between thermal motion and radiation, the energy of these electrons within the atom must be supposed to increase with temperature.
But we know also that in the complete radiation of a white body the radiative energy increases with the fourth power of the absolute temperature.
The energy of radiation resides in the medium and not in the molecule.
The view that visible radiation must be excited by the impact of such an electron is therefore quite consistent with the view that there is no essential difference between the excitement due to chemical or electrical action and that resulting from a sufficient increase of temperature.
An important experiment by C. Gunther 2 seems however to show that the radiation of metallic salts in a flame has an intensity equal to that belonging to it in virtue of its temperature.
This is consistent with Kirchhoff's law and shows that the sodium in a flame possesses the same relative radiation and absorption as sodium vapour heated thermally to the temperature of the flames.
According to independent experiments by Paschen the radiation of the D line sent out by the sodium flame of sufficient density is nearly equal to that of a black body at 'the same temperature.
3 Other more recent experiments confirm the idea that the radiation of flames is mainly determined by their temperature.
With a guess at the specific heat we might then calculate the maximum temperature to which the substance might be raised, if there were no loss by radiation or otherwise.
We might probably with advantage find some definition of what may be called " radiation temperature " based on the relation between radiation and absorption in Kirchhoff's sense, but further information based on experimental investigation is required.
The qualification that the circular function must apply to all time is important, and unless it is recognized as a necessary condition of homogeneity, confusion in the more intricate problems or radiation becomes inevitable.
A limit to homogeneity of radiation is ultimately set by the so-called Doppler effect, which is the change of wave-length due to the translatory motion of the vibrating molecule from or towards the observer.
On the whole it seems probable that the system of moving electrons, which according to a modern theory constitute the atom, is not directly concerned in thermal radiation which would rather be due to a few more loosely connected electrons hanging on to the atom.
Let us now consider the causes which may affect the homogeneity of radiation.
Close to and on either side of the absorptive band µ 2 has large positive and negative values, and if the above expression remains correct the change of frequency would, close to the centre of absorption, be 2 k-2"+3, which for n =3 and k= Io is 1/2000, or 500 times greater than the observed shifts, but this represents now the maximum displacement and not the displacement of the most intense portion of the radiation.
Young, according to which the dark line observed in the centre of each component of the sodium doublet in a Bunsen burner is transparent to a radiation placed behind.
The same author proved that a sufficient thickness of layer raised the radiation to that of a black body in agreement with Kirchhoff's law.
The spectra experimented on by Paschen were band spectra, but as these split up into fine lines the possibility of homogeneous radiation in pure thermal oscillation may be considered as established.
the flames of chlorine in hydrogen) do not apparently emit the usual sodium radiation when a sodium salt is placed in them.
Applying the reasoning to the case of a homogeneous radiation traversing an absorbing medium, we realize that the mutual disturbances of the molecules by collision or otherwise must bring in the free period of the molecule whatever the incident radiation may be.
6 With most bodies the degradation goes on rapidly and the body mainly radiates according to its temperature, but there are cases in which these intermediate stages can be observed and the body seems then to be luminous under the influence of the incident radiation.
showed that the vibrating system of the fluorescent light seems identical with that observed by absorption in the fluted band spectrum, Wood excited the fluorescence by homogeneous radiation and discovered some remarkable facts.
likely to give us an insight into the mechanism of radiation.
His definitely expressed view was that psychical activity is " nothing but a radiation through the cells of the grey substance of the brain of a motion set up by external stimuli."
Increased direct effect of solar radiation compensates for the cold of the nights, and in the few spots where plants have been found in flower up to a height of 12,000 ft., nothing has indicated that the processes of vegetation were arrested by the severe cold which they must sometimes endure.
Here, intense solar radiation by day, which raises the surface when dry to a temperature approaching 80° F., alternates with severe frost by night.
Any contrivance that serves to interrupt radiation, though it may not keep the temperature much above freezing, will be found sufficient.
In the Bessemer process, and indeed in most high-temperature processes, to operate on a large scale has, in addition to the usual economies which it offers in other industries, a special one, arising from the fact that from a large hot furnace or hot mass in general a very much smaller proportion of its heat dissipates through radiation and like causes than from a smaller body, just as a thin red-hot wire cools in the air much faster than a thick bar equally hot.
Becquerel's observation in 1896 that certain uranium preparations emitted a radiation resembling the X rays observed by Rntgen in 1895.
Generally speaking, the radiation is not simple.
It also includes diffusion of heat by internal radiation, which must occur in transparent substances.
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.
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.
The equation of the method is the same as that for the linear flow with the addition of a small term representing the radiation loss.
The conductivity probably changes with temperature in the same way, being proportional to the product of the viscosity and the specific heat; but the experimental investigation presents difficulties on account of the necessity of eliminating the effects of radiation and convection, and the results of different observers often differ considerably from theory and from each other.
The fluvio-marine deposits of the Upper Eocene and Oligocene formations contain an interesting mammalian fauna, proving that the African continent formed a centre of radiation for the mammalia in early Tertiary times.
Except a narrow belt on the north along the Mediterranean shore, Egypt lies in an almost rainless area, where the temperature is high by day and sinks quickly at night in consequence of the rapid radiation under the cloudless sky.
When covered pans are used, the loss of heat by radiation is less, and the salt made is also cleaner.
The temperature of solar radiation was in 1906: highest in the sun 153.8°, recorded in March; the lowest 143.4°, recorded in June.
The highest temperature of nocturnal radiation on grass was 73.1°, recorded in May, and the lowest 67.2°, recorded in January.
The line of permanent snow is much higher on the plateau side in both ranges, the precipitation being greater on the outer sides - those facing the forested lowlands - and the terrestrial radiation being greater from the barren surfaces of the plateau.
The relative humidity of the air along the shores of the Gulf is high, so that exposure to the direct and reflected rays of the sun and radiation from the hot soil are encountered in a moist atmosphere.
In the second zone the climate is more temperate and there is considerable variation in temperature owing to nocturnal radiation.
In any case, it is desirable to diminish the loss of heat as much as possible by polishing the exterior of the calorimeter to diminish radiation, and by suspending it by non-conducting supports, inside a polished case, to protect it from draughts.
As the method is usually practised, the calorimeter is made very small, and the surface is highly polished to diminish radiation.
The surface of the calorimeter and the enclosure should be permanently blackened so as to increase the loss of heat by radiation as much as possible, as compared with the losses by convection and conduction, which are less regular.
If the vacuum jacket is silvered inside, radiation also is reduced to such an extent that, if the vacuum is really good, the external ice bath may be dispensed with for the majority of purposes.
The weight of steam condensed on the body gives a means of calculating the quantity of heat required to raise it from the atmospheric temperature up to ioo° C. in terms of the latent heat of vaporization of steam at zoo° C. There can be no appreciable gain or loss of heat by radiation, if the admission of the steam is sufficiently rapid, since the walls of the enclosure are maintained at too C., very nearly.
At 30° He Considered That, Owing To The Increasing Magnitude And Uncertainty Of The Radiation Correction, There Fig.
Next To The Radiation Loss, The Most Uncertain Correction Was That For Conduction Of Heat Along The 4 In.
Special Observations Were Made To Determine The Corrections For The Heat Supplied By Stirring, And That Lost By Radiation, Each Of Which Amounted To About To% Of The Heatsupply.
If Hdo Is The Radiation Loss In Watts We Have The Equation, Ec=Jsqdo Hdo.
The Rapid Rise From 25° To 75° May Be Due To Radiation Error From The Hot Water Supply, And The Subsequent Fall Of The Curve To The Inevitable Loss Of Heat By Evaporation Of The Boiling Water On Its Way To The Calorimeter.
It was shown by Homer Lane that a mass of gas held in equilibrium by the mutual gravitation of its parts actually grows hotter through radiating heat; the heat gained by the resulting contraction more than counterbalances that lost by radiation.
C. Rntgen of Munich made in 1896 his remarkable discovery of the so-called X or Rntgen rays, a class of radiation produced by the impact of the cathode particles against an impervious metallic screen or anticathode placed in the vacuum tube.
- Variation of energy of radiation corresponding to wavelength 30 µ, with temperature of source.
These yielded a remarkable extension of Pierre Provost's "Law of Exchanges," and enabled him to establish the fact that radiation is not a surface phenomenon, but takes place throughout the interior of the radiating body, and that the radiative and absorptive powers of a substance must be equal, not only for the radiation as a whole, but also for every constituent of it.
Of other papers in which he dealt with this and kindred branches of physics may be mentioned "Observations with a Rigid Spectroscope," "Heating of a Disc by Rapid Motion in Vacuo," "Thermal Equilibrium in an Enclosure Containing Matter in Visible Motion," and "Internal Radiation in Uniaxal Crystals."
When a patient is covered with several blankets, loss of heat from the surface both by radiation and evaporation is to a great extent prevented, but if a cradle be placed over him, so as to raise the bedclothes and allow of free circulation of air around his body, both radiation and evaporation will be increased and the temperature consequently lowered.
In the hottest (western) portions of the true desert on the Mexican border the daily maximum temperature is about IIo° F.; but owing to the rapid radiation in the dry, clear, cloudless air the temperature frequently falls 40-50° in the night.
The daily variation (not uncommonly 60° F.) is of course greatest in the most arid regions, where radiation is most rapid.
But his name is best known for the researches, experimental and mathematical, in radiation which led him, in company with R.
When none of the radiations which fall on a body penetrates through its substance, then the ratio of the amount of radiation of a given wave-length which is absorbed to the total amount received is called the "absorptive power" of the body for that wave-length.
Thus if the body absorbed half the incident radiation its absorptive power would be 2, and if it absorbed all the incident radiation its absorptive power would be r.
The fraction of the incident radiation which is not absorbed by a body gives a measure of its reflecting power, with which we are not here concerned.
On the other hand, those substances which either are good reflectors or good transmitters, are not so luminous at the same temperature; for instance, melted silver, which reflects well, is not so luminous as carbon at the same temperature, and common salt, which is very transparent for most kinds of radiation, when poured in a fused condition out of a bright red-hot crucible, looks almost like water, showing only a faint red glow for a moment or two.
This fact may be expressed by saying that the radiation within a heated enclosure is the same as that of a perfectly black body.
Its temperature must be dominated directly or indirectly by the surface radiation, and since the matter is gaseous and so open to redistribution, the same is true of density and pressure.
Stefan's law of radiation according to the fourth power of the temperature is too difficult to pursue, but if we are content with cognate results we can follow them out mathematically in a hypothetical law of the first power.
The radiation from such a body would be practically nil, no matter how hot the centre was.
By this interchange the inner parts would be opened out and the total radiation raised.
Since the only cause for these convection currents is the statical instability produced by radiation, and the rapid stifling of radiations within the body produces there a temperature gradient falling very slowly, they would be for the most part extremely slight.
condensing power of gravitation at the sun's borders is the pressure of radiation.
The latter is considered below; " The Black .,, it is i nd i cat i ve of the chemical elements from which the lines can proceed, and its state at the time of emission; the former is indicative only of the rate of loss of energy from the sun by radiation, and is inwoven with a remarkable group of physical theory and experiment, known as the theory of the black body, or as black radiation.
The space within is filled with radiations corresponding to this temperature, and these attain a certain equilibrium which permits the energy of radiation to be spoken of as a whole, as a scalar quantity, without express reference to the propagation or interference of the waves of which it is composed.
It will be seen that the maximum ordinates lie upon the curve A9 = constant dotted in the figure, and so, as the temperature of the ideal body rises, the wave-length of most intense radiation shifts from the infra-red X towards the luminous part of the spectrum.
When we speak of the sun's radiation as a whole, it is assumed that it is of the character of the radiations from an ideal radiator at an appropriate temperature.
The first adequate determination of the character as well as amount of solar radiation was made by S.
If we assume that the bolograph of solar energy is simply a graph of amorphous radiation from an ideal radiator, so that the con- Temperature stants cl, c 2, of Planck's formula determined terrestrially apply to it, the hyperbola of maximum intensity is XO = 2, 921 X 10 7; and as the sun's maximum intensity occurs for about X =4900, we find the absolute temperature to be 5960° abs.
The theory refers to radiation homogeneous at all points within a single closed boundary maintained at uniform temperature; in the actual case we have a double boundary, one the sun's surface, and the other infinitely remote, or say, non-existent, and at zero temperature; and it is assumed that the density of radiation in the free space varies inversely as the squares of the distance from the sun.
The fact is that radiation is not a superficial phenomenon but a molar one, and Stefan's law, exact though it be, is not an ultimate theory but only a convenient halting-place, and the radiations of two bodies can only be compared by it when their surfaces are similar in a specific way.
xvi.) that, if for the sake of argument the solar atmosphere be taken as homogeneous in temperature and quality, forming a sheet which itself radiates as well as absorbs, the radiation which an unshielded ideal radiator at 6000° would give is represented well, both in sum and in the distribution of intensity with respect to wave-length, by another ideal radiator - now the actual body of ///4, *...
It seems possible that n is not a large number, and if we take x equal, say, to 200, we come to the most recent estimate - the astronomical - of the date of the earth's glacial epoch, when the sun's radiation was certainly not much more than it is now, while this factor would differ materially from unity.
In consequence of the radiation of heat the whole body will be more condensed than before, but whether it is hotter or colder than before will depend on whether the contraction set up is more or less than enough to restore an exact balance.
The movement towards contraction and consequent rise of temperature which radiation sets up, like other motions, overruns the equilibriumpoint, only however by a minute amount; the accumulated excesses from all past time now stored in the sun would maintain its radiations at their present rate for nX3000 years, that is, for a few thousand years only.
If we suppose the sun's mass once existed in a state of extreme diffusion, the energy yielded by collecting it into its present compass would not suffice to maintain its present rate of radiation for more than 17,000,000 years in the past; nor if its mean density were ultimately to rise to eight times its present amount, for more than the same period in the future.
If the sources of energy within the atom can be drawn upon, and the phenomena of radio-activity leave no doubt about this, there is here an incalculable source of heat which takes the cogency out of any other calculation respecting the sources maintaining the sun's radiation.
The radiation from a spot changes little as it approaches the sun's limb; in fact Hale and Adams find that the absorption from the limb itself differs from that of the centre of the disk in a manner exactly resembling that from a spot, the same lines being strengthened or weakened in the same way, though in much less degree, with, however, one material exception: if a line is winged in the photosphere the wings are generally increased in the spot, but on the limb they are weakened or obliterated.
A waterlogged soil is impenetrable by air, and owing to the continuous process of evaporation and radiation, its temperature is much below that of drained soil.
There is another point of view from which mammals are of especial importance in regard to geographical distribution, namely their comparatively late rise and dispersal, or " radiation," as compared with reptiles.
If eastern Central Asia were tentatively given as the centre of radiation of the group, this might perhaps best accord with the nature of the case.
According to Tyndall, 9 0% of the radiation from the electric arc is non-luminous.
The arc being struck in the usual way between two carbons, a concave mirror, placed close behind it, caused a large part of the radiation to be directed through an aperture in the camera and concentrated to a focus outside.
Since the rays used by Tyndall in these experiments are similar to those emitted by a heated body which is not hot enough to be luminous, it might be thought that the radiation, say from a hot kettle, could be concentrated to a focus and employed to render a small body luminous.
It would, however, be impossible by such means to raise the receiving body to a higher temperature than the source of radiation.
Very, applied it to determine the moon's radiation at the Allegheny observatory.
His results for the ratio of the total radiation of the full moon to that of the sun ranged from 1: 70,000 to 1: 110,000, which were in substantial agreement with those of Rosse, who found 1: 82,000.
When Langley published his work the law of radiation as a function of the temperature was not yet established.
Stefan's law of radiation, on the other hand, shows that the temperature must have been about the boilingpoint in order that the observed amount of heat might be radiated.
This is in fair agreement with the computed temperature due to the sun's radiation upon a perpendicular absorbing surface when no temperature is lost through conduction to the interior.
The agreement thus brought about between the results deduced from the law of radiation and the most delicate observa tions of the quantity of heat radiated is of great interest, as showing that the theory of cosmicai temperature now rests upon a sound basis.
The recent discoveries growing out of the investigation of newly discovered forms of radiation lead to the conclusion that the question of the forms of matter in the stars has far wider range than the simple question whether any given element is or is not found outside our earth.
With a modification to be mentioned presently, we may regard them as intensely hot bodies, probably at a temperature higher than any we can produce by artificial means, of which the superficial portions have cooled off by radiation into space.
(The rarity of the air and the great radiation during the night cause the temperature in the Sahara to fall occasionally to freezing point.) Farther south, the heat is to some extent modified by the moisture brought from the ocean, and by the greater elevation of a large part of the surface, especially in East Africa, where the range of temperature is wider than in the Congo basin or on the Guinea coast.
ix.) have built up a theory of the structure of active media, but in the instances in which static spirality has been shown to be effective in producing optical rotation the coarse-grainedness of the structure is comparable with the wave-length of the radiation affected.
This subject is treated in the article Magneto-Optics, to which the reader is also referred for John Kerr's discovery of the effect on polarization produced by reflection from a magnetic pole, and for the action of a magnetic field on the radiation of a source - the "Zeeman effect."
He also determined the effect of change of temperature distribution on the rate of generation of heat by the current; and on the external loss of heat by radiation, convection and conduction.
Historically the unit was the rad derived from " radiation absorbed dose " .
antenna radiation (normal to the plane of the loop) will be polarized parallel to the short sides of the loop.
Also the metal spacecraft protected the astronauts from most of the radiation.
It is also attenuated by dust, smoke, cloud or any medium which obscures radiation at that wavelength.
audio-frequency range, and the consequent radiation of noise.
One sees the imprint of these primordial fluctuations as small temperature perturbations in the cosmic microwave background radiation.
This " horizon problem " makes it difficult to account for the uniformity of the cosmic background radiation.
background radiation levels.
CMB 3K: The cosmic microwave background radiation, R. B. Partridge, pub.
Study of the uncertainty in estimation of the exposure of non-human biota to ionizing radiation.
This is called magnetic bremsstrahlung or synchrotron radiation (after radiation observed from particle accelerators by that name ).
bremsstrahlung radiation produced by the acceleration of charged particles.
broad in nature and aims to cover all uses of optical radiation in medicine.
But the industry has the potential for accidental radiation releases and produces radioactive byproducts that require safe storage for decades.
calculated radiation spectra were used in further calculations of detector response, which in turn improved our understanding of dosimetry for cancer therapy.
cells in vitro to 2450 MHz radiation causes DNA damage.
In normal cellphone use such glycoproteins diffuse laterally back again on cessation of the field or radiation.
cellphone radiations can be assessed in the same way as ionizing radiation.
One possibility is to assume isotropic sky conditions at all times and so simplify computation since diffuse radiation is then independent of direction.
concurrent with radiation and surgery is the treatment of choice for unresectable disease.
concurrent chemotherapy (along with radiation )?
Greater ionizing radiation from the Sun during those times also tends to produce more nuclei in the atmosphere for cloud condensation.
cosmic radiation during flight operations.
Phycobilisomes appear to have been very advantageous to early cyanobacteria, evolving in shallow marine environments protected from UV radiation.
degrade as a result of the radiation.
desiccatechens and microbes even live inside translucent rocks to shelter from high radiation levels and desiccating winds!
dilate in order that more blood heat may be lost by radiation from the skin.
Radioactivity The phenomenon whereby atoms undergo spontaneous random disintegration, usually accompanied by the emission of radiation.
disquiet about potentially harmful health effects arising from the radiation emitted from these facilities is acknowledged.
A person can receive a greater radiation dose on a plane flight to Spain then from an x-ray of the wrist or shoulder.
This photograph shows an irradiator that is used at NPL to calibrate dosimeters for use in the radiation processing industry.
dosimeter badges to measure their radiation dose.
Selection of the Trigger Point box brings up anatomical drawings showing the TP and pattern of pain radiation for a range of muscles.
At the end of this process the remnant star will cease to emit radiation and will become a ' black dwarf ' .
Radiation therapy is successful in relieving dysphagia in approximately 50% of patients.
We know from classical electrodynamics that an accelerated charge emits radiation.
electromagnetic radiation from mobile phones would hardly have been of use 50 years ago!
The radiation emitted from a cluster comes from a very small fraction of the mass present.
Radioactivity The property of radionuclides of spontaneously emitting ionizing radiation.
emitting ionizing radiation.
emitters of strong radiation.
COMARE will set up a working group to study the risks associated with internal radiation emitters rather than exposure to external sources.
The buntings exemplify local adaptive radiation, but may be hybridizing which could eventually produce a new species endemic to the island.
The diagnosis of chronic radiation enteritis may be difficult to make.
When in hydrostatic equilibrium and gravitational energy is its source of heat and radiation, it is called a pre-main sequence star.
evaporatelight from the emission of radiation from the ionized gas and from the white hot evaporating particle.
Adaptive radiation and molecular evolution of Cicindela tiger beetles.
This makes up 50% of our total radiation exposure from all sources.
His article is popular and he's for real but please, avoid radiation fallout affected food and water.
All this caused by ionizing radiation fallout from the nuclear weapons.
Personnel working with radar, X-ray equipment or near other sources of radiation wear radiation dosage film badges that detect their level of radiation.
If a molecule which absorbs UV radiation does not fluoresce it means that it must have lost its energy some other way.
Radiation Shielding (6 lectures) g (6 lectures) g -ray and neutron shielding calculations; g -ray attenuation and build-up factors.
Ionizing radiation means gamma rays, x-rays etc., which directly or indirectly are capable of producing ions (charged particles ).
Gamma Ray Astronomy Primary cosmic gamma ray Astronomy Primary cosmic gamma rays (300 GeV) are studied using the atmospheric Cerenkov radiation technique.
METHODS: Patients with newly diagnosed high-grade gliomas received BCNU and cisplatin after surgery, both before and during definitive radiation therapy.
In 1978 Durney et al., had compiled a Dosimetry handbook for radiofrequency radiation (Durney et al., 1978 ).
Unexpectedly, the radiation hardness has been found to be worse than silicon under charged hadron irradiation.
There are two types of potential hazard posed by the use of DU: a chemical toxicity hazard and a radiation hazard.
Solar furnaces: solar radiation is concentrated on a small point by hundreds of reflecting surfaces called heliostats.
high watercting equipment is suspended in 200 tons of high purity water to shield the dark matter detectors from this radiation.
This absorption would in part produce hot spots from near field radiation.
FPC can contain a set of ordered markers, which are generally from a genetic or radiation hybrid map.
More infrared radiation reaches the detector resulting in crisp infrared radiation reaches the detector resulting in crisp infrared images.
The solar radiation on this planet is nearly insensible.
insolation data in the shading/insolation database now accounts for all radiation entering the zone.
Urea is the main form in which nitrogen is excreted in mammals UV radiation invisible rays that are part of the electromagnetic spectrum.
ionizeddition, CT exposes you to more ionizing radiation than do regular X-rays.
irradiated with gamma radiation in fly factories, which renders them sterile but otherwise leaves them reproductively active.
A standard dipole radiation pattern is not isotropic - it looks bit like a donut with the antenna in place of the hole.
And how many were killed in the radiation leak?
In order to deliver the radiation to the patient we use devices called medical linear accelerators, or " linacs " .
These results have quite important meaning in the survey of genomic locus which is responsible for radiation hypersensitivity.
low-level radiation for about a year.
luminosity sources must have higher accretion rates and provide a more intense ionizing radiation field.
luminous efficacy, i.e., the useful visible light in relation to the total energy of the radiation is high.
Investigation of the effects of ionizing radiation on the physical properties of extracellular matrix macromolecules.
Although there are huge benefits from regular mammography, there is an extremely small radiation risk associated with the examination.
In fact, Eberlein says, sonoluminescence may represent the first observable manifestation of quantum vacuum radiation.
maser action, where the radiation intensity is very low.
After treatment with both radiation to the head and neck and intrathecal methotrexate the patient achieved complete symptom resolution.
The gamma knife delivers a single high dose of radiation at targets of just several millimeters up to 3 centimeters in diameter.
We carefully follow the current national guidelines for dental radiography and use modern, low radiation dose dental x-ray machines.
monochromatic radiation leaving the exit slit is focussed onto the sample by a toroidal mirror.
For instance, chemicals in tobacco include mutagens, and several types of ionizing radiation have mutagenic effects.
In its simplest form, seeds are exposed to radiation or chemical mutagens to cause random unpredictable genetic changes in crops.
There is the risk of radiation necrosis of the skin.
neoplastic transformation in an inhomogeneous radiation field: An effect of the presence of heavily damaged cells: Sigg et al.
AB - OBJECTIVE: Radiation optic neuropathy usually occurs months to years after exposure of the anterior visual pathways to ionizing radiation.
Ozone is a gas that prevents much noxious UV radiation from reaching the Earth's surface.
Sun's energy is produced by nuclear fusion, which gives off electromagnetic radiation.
There are also other relevant links about such topics as nuclear reactors, natural nuclear reactors and background radiation.
Searches for elements with specific radiation energies or for specific nuclides are allowed.
omnidirectional radiation pattern?
Reviewed by Alastair J Munro, professor of radiation oncology What is stomach cancer?
He had manifested a gradual onset of upper back pain with radiation to the left chest wall for 3 months.
ozone in the stratosphere absorbs ultra-violet radiation emitted by the Sun.
Then the strong interacting particles experience additional radiation of soft or collinear partons described by means of the parton shower.
penetrateal card had to pay just emit the penetrating radiation.
periodicity of 110,000 years, and affects the total amount of solar radiation reaching the Earth.
measuring the photoelectron current at 0º and 90º to the polarization vector of the synchrotron radiation yields the polarisations, given below.
photoionization rates are obtained by convolving the radiation field with the photoionization cross section.
Students should have an interest in experimental semiconductor physics and/or radiation physics, and in the application of radiation detectors to medical imaging.
Patients who have received bleomycin are also at greater risk of radiation pneumonitis.
Certain paints such as unsaturated polyester can be cured using radiation.
polymorphous light eruption Long term exposure to ultraviolet radiation ultimately causes skin aging and skin cancers.
This is comparatively puny slice, the potential for harm from radiation increases with frequency.
finding the powerful quasars responsible for the X-ray background radiation.
Note, no sensing of UV or of ionizing radiation.
In addition, CT exposes you to more ionizing radiation than do regular X-rays.
radiation emitted from a cluster comes from a very small fraction of the mass present.
The primary health effect from high exposure levels of non-ionising radiation arises from heat generation in body tissue.
Various body tissues absorb the radiation at different rates, causing various shadows to appear on the plate.
X-ray - pictures of the bones taken using electromagnetic radiation.
Destruction of the ozone layer results in an increase in the amount of harmful ultraviolet radiation reaching the Earth's surface.
Green house gases absorb energy from the diffused solar radiation, which cause them to warm up.
cosmic radiation also keeps us alive - thanks to all those photons which make it through from the sun.
More infrared radiation reaches the detector resulting in crisp infrared images.
Be able to describe the use of infra-red radiation in night photography.
radiation dose on a plane flight to Spain then from an x-ray of the wrist or shoulder.
radiation therapy at some time during the course of their disease.
Much higher levels of direct investment by industry to synchrotron radiation sources are reported in the US.
This chaotic motion may be caused by the powerful ultraviolet radiation from the luminous, massive stars.
The Ozone layer which protects us from harmful gamma radiation has recently disappeared over the tip of South Africa.
Know that ultra-violet radiation is produced in fluorescent lights.
Trying to get info on health effects from microwave radiation.
Similarly, more longwave radiation is emitted to space in the tropics than at high latitudes.
This radiation reactance needs to be tuned out, to get power transfer from the generator to the radiated field.
reactor compartment that completely protects the crew from radiation.
red-shifted radiation from the Big Bang.
The polymer grid stays intact longer than a jute scrim shaded from ultra-violet radiation by vegetation to reinforce the root matrix of the turf.
shortwave radiation from the Sun begins to heat the ground.
solar radiation, which cause them to warm up.
What is the largest wavelength of radiation that will be diffracted by a lattice plane of the interplanar spacing d?
It absorbs solar ultraviolet radiation, which heats the stratosphere.
Above the middle stratosphere the absorption of solar ultraviolet radiation by oxygen also becomes important.
Late sequelae include strictures, chronic radiation enteritis, malabsorption, or gastrointestinal obstruction.
Some areas of specialized knowledge such as water chemistry or radiation protection can be vital.
synchrotron radiation or x-rays.
We've only just begun looking for X-ray synchrotron radiation.
These experiments are performed at several 3 rd generation synchrotron radiation sources throughout Europe.
There are also UK requirements for a low energy synchrotron radiation source.
Harford, J.J. & Squire, J.M. (1997) Time-resolved diffraction studies of muscle using synchrotron radiation.
synchrotron radiation sources are reported in the US.
synchrotron radiation facilities for industrial research " (17 ).
terahertz radiation using tabletop sources, complementing 4GLS work at Daresbury.
Other scientists have discovered why patients who undergo radiation therapy for brain, head or neck cancer suffer from some mental decline.
External or internal radiation therapy can often cause damage to the salivary glands, leading to a permanently dry mouth.
Top of page 11: How does a radiation thermometer work?
This will directly benefit users of radiation thermometry resulting in tighter process control with the associated environmental benefits.
It also strips some material away from Io which forms a torus of intense radiation around Jupiter.
This material becomes ionized in the magnetic field and forms a doughnut-shaped cloud of intense radiation referred to as a plasma torus.
There is the further problem that radiation emitted is not a good tracer of mass, which is what we are most interested in.
Water vapor in the upper troposphere has a very large impact on the radiation balance.
turnstile antennas are commonly used as transmitting antennas when horizontal polarization is required together with omnidirectional radiation.
ultrashort pulse lasers are used to manipulate atoms and molecules and to generate non-classical radiation using non-linear optical processes.
Stratospheric ozone acts as a shield by absorbing potentially harmful ultraviolet (UV) radiation which would otherwise reach the earth's surface.
ultraviolet radiation level changes over the year.
Sunlight consists of electromagnetic radiation of wavelengths from 20 microns at the far infrared end to 200 nanometres at the far ultraviolet end.
Ozone is formed naturally in the upper stratosphere by short wavelength ultraviolet radiation.
Prolonged enhancement in surface ultraviolet radiation during the Antarctic spring of 1990.
unsaturated polyester can be cured using radiation.
This features CWOP (Citizen Weather) data upload and support for solar radiation (Sun) sensors.
UVB radiation has been reported.
This is to determine the role of ionizing radiation in the treatment of clinical posterior uveitis.
vagus nerve stimulator implant that he thought might be affected by any radiation from a computer.
violet radiation A small part of the radiation from the sun which can cause skin cancer.
wavelength of the radiation varies we can measure the velocity of the Hydrogen, using the Doppler shift.
wavelength ultraviolet radiation it seems to have little action.
Polyester fibers exposed to UV radiation will be considerably weakened over time.
weather forecasters use the Solar UV Index to show how much UV radiation is reaching the earth's surface.
Exner attributes the double daily maximum, which is largely a consequence of the 12-hour wave, to a thin layer near the ground, which in the early afternoon absorbs the solar radiation of shortest wave length.
If the atmosphere at different heights is exposed to ionizing radiation of uniform intensity the rate of production of ions per cc., q, will vary as the pressure.
Special experiments were made to determine the work done against resistances outside the vessel of water, which amounted to about 006 of the whole, and corrections were made for the loss of heat by radiation, the buoyancy of the air affecting the descending weights, and the energy dissipated when the weights struck the floor with a finite velocity.
Bellini and Tosi, who have devised instruments, called radiogonimeters, for projecting radiation in required directions and locating the azimuth of a transmitting station.
He was distinguished as the discoverer of radioactivity, having found in 1896 that uranium at ordinary temperatures emits an invisible radiation which in many respects resembles RÃ¶ntgen rays, and can affect a photographic plate after passing through thin plates of metal.
These low temperatures are evidently caused by the radiation of heat from the snow-surface in the rarefied air in the interior.
It has been suggested, however, that a prolonged period of volcanic activity may reduce the air temperature to a marked degree by throwing large quantities of dust into the atmosphere: this will act by preventing the penetration of solar radiation.) During a period of prolonged glaciation water becomes withdrawn from the ocean, for rainfall goes to form solid ice-caps that accumulate upon polar and continental land areas.
Transmit antenna convert energy of generator into radiation of electromagnetic waves.
The radiation passing out from an opening in the furnace falls upon a concave mirror in a telescope and is focused upon a thermoelectric couple.
In ordinary reverberatory and other heating furnaces the burning fuel is without the mass, so that the vessel containing the charge, and other parts of the plant, are raised to a higher temperature than would otherwise be necessary, in order to compensate for losses by radiation, convection and conduction.
(See Radiation.) The word actinometer is now usually applied to instruments for measuring the actinic or chemical effect of luminous rays; their action generally depends upon photochemical changes (see Photo-Chemistry).
If heat passes " of itself " from a higher to a lower temperature by conduction, convection or radiation, the transfer cannot be reversed without an expenditure of work.
The temperature of a gas is measured by the mean energy of translation of its molecules, which are independent of each other except during the brief intervals of collision; and collision of the separate molecules with the blackened surface of a vane, warmed by the radiation, imparts heat to them, so that they rebound from it with greater velocity than they approached.
(See RADIATION.) More recently J.
Great irregular variations in radiation and convection sometimes produce a remarkably abrupt change of temperature at a certain depth in calm water; the layer in which this sudden change occurs has been termed the Sprungschicht.
Towards the end of summer the upper layers have been warmed to a depth which indicates how far the influence of solar radiation and convection have reached.
According to modern measurements the solar radiation imparts almost 3 grammecalories of energy per minute per square centimetre at the distance of the earth, which is about IÃ¯¿½3 X io s ergs per sec. per cm.
If c is the velocity of radiation in free space and, u the refractive index of a transparent body, V= c/Ã¯¿½; thus it is the expression c2 fÃ¯¿½ 2 (u'dx-}-v'dy+w'dz) that is to be integrable explicitly, where now (u',v',w') is what is added to V owing to the velocity (u,v,w) of the medium.
Hence the paths and times of passage of all rays relative to the material system will not be altered by a uniform motion of the system, provided the velocity of radiation relative to the system, in material of index Ã¯¿½, is diminished by Ã¯¿½ -2 times the velocity of the system in the direction of the radiation, that is, provided the absolute velocity of radiation is increased by 1-Ã¯¿½2 times the velocity of the material system; this involves that the free aether for which, u is unity shall remain at rest.
(See Radiometer.) Next to these researches on the pressure of radiation, which, by forming the mechanical link between radiation and matter, are fundamental for the thermodynamics of radiant energy, the most striking recent result has been the discovery of H.
Hagen that for dark heat rays of only about ten times the wave-length of luminous radiation, the properties of metals are determined by their electric resistance alone, which then masks all resonance due to periods of free vibration of the molecules; and, moreover, that the resistance for such alternations is practically the same as the ohmic resistance for ordinary steady currents.
(See Radiation.) Finally, reference should be made to the phenomena of radioactivity, whether excited by the electric discharge in vacuum tubes, foreshadowed in part by Sir Wm.
While we have seen that the radiation of sodium vapour has an intensity corresponding to that of the pure thermal radiation at the temperature of the flame, other flames not containing oxygen (e.g.
Here, intense solar radiation by day, which raises the surface when dry to a temperature approaching 80Ã‚° F., alternates with severe frost by night.
Becquerel's observation in 1896 that certain uranium preparations emitted a radiation resembling the X rays observed by RÃ¶ntgen in 1895.
The heat generated by the current C at a point x where the temperature-excess is 0 is equal per unit length and time (t) to that lost by conduction -d(gkdo/dx)/dx, and by radiation hpo (emissivity h, perimeter p), together with that employed in raising the temperature gcdo/dt, and absorbed by the Thomson effect sCdo/dx.
The temperature of solar radiation was in 1906: highest in the sun 153.8Ã‚°, recorded in March; the lowest 143.4Ã‚°, recorded in June.
The highest temperature of nocturnal radiation on grass was 73.1Ã‚°, recorded in May, and the lowest 67.2Ã‚°, recorded in January.
The weight of steam condensed on the body gives a means of calculating the quantity of heat required to raise it from the atmospheric temperature up to iooÃ‚° C. in terms of the latent heat of vaporization of steam at zooÃ‚° C. There can be no appreciable gain or loss of heat by radiation, if the admission of the steam is sufficiently rapid, since the walls of the enclosure are maintained at too C., very nearly.
At 30Ã‚° He Considered That, Owing To The Increasing Magnitude And Uncertainty Of The Radiation Correction, There Fig.
The Rapid Rise From 25Ã‚° To 75Ã‚° May Be Due To Radiation Error From The Hot Water Supply, And The Subsequent Fall Of The Curve To The Inevitable Loss Of Heat By Evaporation Of The Boiling Water On Its Way To The Calorimeter.
Phys., 51, p. 225) the discovery that these cathode particles or corpuscles could pass through a window of thin sheet aluminium placed in the wall of the vacuum tube and give rise to a class of radiation called the Lenard rays.
C. RÃ¶ntgen of Munich made in 1896 his remarkable discovery of the so-called X or RÃ¶ntgen rays, a class of radiation produced by the impact of the cathode particles against an impervious metallic screen or anticathode placed in the vacuum tube.
In the hottest (western) portions of the true desert on the Mexican border the daily maximum temperature is about IIoÃ‚° F.; but owing to the rapid radiation in the dry, clear, cloudless air the temperature frequently falls 40-50Ã‚° in the night.
The daily variation (not uncommonly 60Ã‚° F.) is of course greatest in the most arid regions, where radiation is most rapid.
If we assume that the bolograph of solar energy is simply a graph of amorphous radiation from an ideal radiator, so that the con- Temperature stants cl, c 2, of Planck's formula determined terrestrially apply to it, the hyperbola of maximum intensity is XO = 2, 921 X 10 7; and as the sun's maximum intensity occurs for about X =4900, we find the absolute temperature to be 5960Ã‚° abs.
xvi.) that, if for the sake of argument the solar atmosphere be taken as homogeneous in temperature and quality, forming a sheet which itself radiates as well as absorbs, the radiation which an unshielded ideal radiator at 6000Ã‚° would give is represented well, both in sum and in the distribution of intensity with respect to wave-length, by another ideal radiator - now the actual body of ///4, *...
If we are dealing with comparatively recent periods there is no evidence of progressive change, but if we go to remote epochs and suppose the sun to have once been diffused in a nebulous state, it is clear that its shrinkage, in spite of radiation, has left it hotter, so that the shrinkage has outrun what would suffice to maintain its radiation.
Sunscreens for plants protects them from ultraviolet and infrared radiation.
Finding the powerful quasars responsible for the X-ray background radiation.
Destruction of the ozone layer results in an increase in the amount of harmful ultraviolet radiation reaching the Earth 's surface.
Cosmic radiation also keeps us alive - thanks to all those photons which make it through from the sun.
AB - Most patients with plasma cell tumors receive radiation therapy at some time during the course of their disease.
X-ray radiation can be generated using radioisotope sources or X-ray tubes.
The primary goal of the Experimental Radiation Therapeutics Group is the preclinical and early clinical development of radiopharmaceutical agents for the treatment of cancer.
This has consequences for the radiation dose rate to the skin from radon decay products which is much higher outdoors compared with indoors.
The entire process takes place inside a heavy shielded reactor compartment that completely protects the crew from radiation.
The radiation was isotropic and it corresponded to a temperature that was consistent with red-shifted radiation from the Big Bang.
Low density material allows greater radiation to reach the scintillation detector.
At sunrise, the shortwave radiation from the Sun begins to heat the ground.
The electron wave is created by exciting a core hole electron with synchrotron radiation or x-rays.
We 've only just begun looking for X-ray synchrotron radiation.
Strong deliberate efforts must be made to ease the utilization of the national synchrotron radiation facilities for industrial research (17).
It covers radiation detection, cadmium zinc telluride detectors and X-ray fluorescence.
To generate and detect terahertz radiation using tabletop sources, complementing 4GLS work at Daresbury.
These considerations do not mean the radiation arrow reduces in any sense to the thermodynamic arrow.
The contribution of effective dose from terrestrial gamma radiation and from airborne radon and thoron daughter products depends on the local geology.
For example, radiation dose from modern computed tomography scanners may be in excess of that produced by older models.
This technique uses the properties of synchrotron radiation, i.e. linearly polarized and tunable radiation.
Turnstile antennas are commonly used as transmitting antennas when horizontal polarization is required together with omnidirectional radiation.
In this Center, ultrashort pulse lasers are used to manipulate atoms and molecules and to generate non-classical radiation using non-linear optical processes.
Stratospheric ozone acts as a shield by absorbing potentially harmful ultraviolet (UV) radiation which would otherwise reach the earth 's surface.
The peak daily ultraviolet radiation level changes over the year.
An increased risk of skin cancer in psoriatic patients treated with a combination of coal tar and UVB radiation has been reported.
He also has a vagus nerve stimulator implant that he thought might be affected by any radiation from a computer.
Ultra violet radiation A small part of the radiation from the sun which can cause skin cancer.
The level of radiation of the typical mobile phone is around 0.2 to 1 watt per kilogram.
By tracing how the wavelength of the radiation varies we can measure the velocity of the Hydrogen, using the Doppler shift.
Unless it is exposed to longer wavelength ultraviolet radiation it seems to have little action.
UK weather forecasters use the Solar UV Index to show how much UV radiation is reaching the earth 's surface.
Resources such as solar radiation, hydroelectricity, wind and the tides are all easily replenished resources.
They are basically large, flat devices that collect solar radiation and convert that energy to electrical energy.
The problem with these early cells was that they could only convert a certain "band" or wavelength of solar radiation.
The term "photovoltaic" refers to the conversion of solar radiation into electrical voltage and current.
Levels of natural solar radiation vary, and with that variation the level of power produced by photovoltaic cells also varies.
Since solar radiation is unlimited in space, these inefficient solar cells were more than enough to power satellite electrical systems.
Increased solar activity changes the Earth's solar radiation levels, thereby causing short-term warming cycles.
Although this blocking action might appear to reduce solar radiation, the opposite is true.
These patches give off greater than normal radiation, and they are more powerful than the darker, cooler patches.
Most man-made causes of global warming result from an increase in greenhouse gases, which are gases that trap or absorb infrared radiation emitted from the planet.
Greenhouse gases are those that absorb and emit infrared radiation, significantly affecting the planet's temperature.
Solar cells, or photovoltaic cells, absorb radiation from the sun and create electricity.
For passive design, this involves the natural methods of conduction, convention and radiation, which you may recall from science class.
In certain areas, the chemicals create holes that allow ultraviolet rays to make it through the atmosphere to the Earth where the radiation causes damage to plants and wildlife and increases the risk of skin cancer in humans.
Nuclear power can give off radiation, at the mining source, during transportation of raw materials, at the reactor itself, and from leaks of improperly contained waste.
While efforts are made to contain the radiation produced during the fission process, and containment systems are in place to help prevent leaks and contamination, nuclear energy does have its drawbacks.
Cracks in the cement, failure of the pipe system, which brings in clean water and other systems failures can lead to dangerous amounts of radiation being leaked into nearby communities.
Since uranium is an unstable element, this leaves a great deal of room for error, radiation leaks and risks fission happening too soon, where it cannot be contained.
This can be dangerous, since the waste products can be unstable, produce radiation if not properly sealed and pose a threat from terrorists that may wish to convert this waste into weaponry.
The use of direct solar power requires only one step, called electromagnetic radiation, in order to convert solar energy into useable power.
Northern states and New England do not receive the same amount of daily solar radiation.
Solar energy enters the Earth's atmosphere in the form of solar radiation.
By using a method called photovoltaics, researchers found they can generate electrical power by funneling the sun through a specific medium like copper or silicon to harness the energy from solar radiation.
However, the benefits are known to outweigh the risks for people who live in areas that garner at least the national average of solar radiation per year.
The herbs and spices are also radiation and ozone treatment-free.
He says doctors gave him the option of radiation (chemo), but thought having it removed would be the better choice.
She underwent a lumpectomy and radiation treatment.
She followed the surgery with radiation therapy and was soon declared cancer free.
This new heating device uses electromagnetic radiation to heat the human body from the inside out, similar to how warmth is received from the sun.
Although it is not common, radiation is sometimes used to deepen the pink color of Kunzite gemstones.
Some practitioners use citrine to counter the effects of radiation exposure and aid digestion in the absorption of minerals and antioxidants.
The USDA defines organic as "food produced without using synthetic fertilizers and pesticides, bioengineering and radiation."
Irradiated food is exposed to radiation, either through gamma rays, x-rays or electron beams, in an effort to kill microorganisms that can cause it to rot.
Another problem with irradiation is that it is still up for debate whether traces of radiation remain in the food after it is treated.
In addition, these foods cannot be made with prohibited methods such as ionizing radiation.
The problem is that exposure to ultraviolet (UV) rays cause a form of radiation which alters the cellular integrity of skin cells.
The sun's rays emit ultraviolet (UV) radiation, which damages the outer layer of the skin.
To combat the effects of UV radiation, a sunscreen product with a Sun Protection Factor (SPF) of 30 or higher should be applied 15 or 20 minutes before venturing outside.
In fact, according to Johnson and Johnson, the makers of the contacts, the pair will block anywhere from 82 percent of UVA radiation and up to 97 perfect of UVB radiation.
UV stands for Ultra Violet radiation, a high-energy radiation that comes from the sun and is capable of damaging living organisms.
This type of radiation contributes to premature aging, wrinkling and has recently been linked to skin cancer.
UVB radiation is much more dangerous and has been sited as one of the main causes of major skin cancers.
While such a reflective coating will not block UV radiation (that's what UV coating is for), it will protect your eyes from the strain of dealing with high-glare, or very bright light conditions.
UVA: These radiation rays are virtually harmless, but are typically absorbed by the lens of the eye.
UVC Rays: UVC rays are the type of radiation that is absorbed by the upper atmosphere of our planet.
When treated with a UV resistant coating, glass and plastic (CR-39) lenses are all capable of blocking UV radiation.
Now that the damage of UV radiation is so well documented in the scientific community, it also stands to reason that we must protect the delicate eyes and skin of both babies and children.
The technology in question was the special coating NASA gives the portholes on its satellites to protect them from radiation found in outer space.
UVA, UVB, and UVC protection on all lenses to provide maximum protection against the entire range of potentially harmful radiation.
The UV index is a way of indicating how strong the sun's harmful rays (radiation) are at various times of the day.
The word usage examples above have been gathered from various sources to reflect current and historial usage. They do not represent the opinions of YourDictionary.com.