If evacuated tubes are compared with flat-plate collectors on the basis of area of roof occupied, a different conclusion might be reached than if the areas of absorber were compared.

If evacuation orders are given too early, the hurricane can change course and leave the evacuated area unscathed.

If the emergency affects the entire train, then guests are evacuated to the surface of the beam.

Note: If 1/2-inch panel board is used inside and out, or 5/8-inch one side and 3/8-inch the other, and 1/8-inch glass is used, stock lumber in Af, Af, and Af can be used in making the glass panels.

If the glass is damaged, atmospheric pressure can collapse the vacuum tube into dangerous fragments which accelerate inward and then spray at high speed in all directions.

If later heat treatments cause this glass to become partly crystalline, the resulting material is known as a glass-ceramic, widely used as cooktop.

If a person's hands are placed around the glass without touching it, the vanes will turn slowly or not at all, but if the glass is touched to warm it quickly, they will turn more noticeably.

If the glass is cooled quickly in the absence of a strong light source by putting ice on the glass or placing it in the freezer with the door almost closed, it turns backwards ( i. e. the silver sides trail ).

If a similar ball is charged by the same glass rod, it is found to repel the first: the charge acts to force the two balls apart.

If a second piece of glass be rubbed with a second piece of resin, and if the piece be then separated and suspended in the neighbourhood of the former pieces of glass and resin, it may be observed:

If a body electrified in any manner whatever behaves as the glass does, that is, if it repels the glass and attracts the resin, the body is said to be ' vitreously ' electrified, and if it attracts the glass and repels the resin it is said to be ' resinously ' electrified.

If shots are taken out of sequence, as is often the case, he will be alert to make sure that that beer glass is in the appropriate state.

If the pane is not a good insulator ( such as a single pane window ), water vapour condenses on the glass forming patterns.

* If medieval glass has flowed perceptibly, then ancient Roman and Egyptian objects should have flowed proportionately more — but this is not observed.

* If glass flows at a rate that allows changes to be seen with the naked eye after centuries, then the effect should be noticeable in antique telescopes.

If there is no cell attached to the glass, there will be no interference.

If the store is crammed with used athletic gear, old stereos, and old tools, the store owner must spend time and money shelving and sorting items, displaying them on different stands or in glass cases, and monitoring customers to prevent shoplifting.

If there are two horizons there is side error ; adjust the horizon glass / mirror until the stars merge into one image or the horizons are merged into one.

If for example, visible light were traveling through acrylic glass ( with an index of refraction of 1. 50 ) into air ( with an index of refraction of 1. 00 ), the calculation would give the critical angle for light from acrylic into air, which is

If the drain is opened and the tumbler is kept in position over the hole, the water in the tumbler drains out leaving the glass filled with air, and this then acts as the plug.

If the wind blows into the mouth of a tube it causes an increase of pressure on one side of the manometer.

If the collar at the bottom of the tube is adjusted so more air can mix with the gas before combustion, the flame will burn hotter, appearing blue as a result.

If the holes are closed, the gas will only mix with ambient air at the point of combustion, that is, only after it has exited the tube at the top.

If the risk of asphyxiation is deemed to be high, doctors may use various devices ( such as an oropharyngeal airway, nasopharyngeal airway or endotracheal tube ) to safeguard the airway.

If you are a " perfectionist ", multiply the bore diameter by 0. 82 and subtract this value from the tube length.

If holding the guitar in the normal vertical position, it is more common to use the tube type of slide.

If the woman stands upright, the vaginal tube points in an upward-backward direction and forms an angle of slightly more than 45 degrees with the uterus.

If a visible output was needed, a second tube with a phosphor coating was used as a display device.

If correctly selected, it reaches terminal velocity, which can be measured by the time it takes to pass two marks on the tube.

If one considers the flux of the electric field vector, E, for a tube near a point charge in the field the charge but not containing it with sides formed by lines tangent to the field, the flux for the sides is zero and there is an equal and opposite flux at both ends of the tube.

It occurs because of inter-molecular attractive forces between the liquid and solid surrounding surfaces ; If the diameter of the tube is sufficiently small, then the combination of surface tension and forces of adhesion between the liquid and container act to lift the liquid.

* If the gland retains its shape as a tube throughout it is termed a tubular gland.

If a GM tube is exposed to a steady radiation source and the applied voltage increased from zero, at first the count rate increases rapidly ; at a certain voltage the rate of increase flattens out ( only changing a few per cent for every 100 volts increase ).

If the applied voltage is too high, a continuous glow discharge is formed and the tube cannot detect radiation.

If nothing were done to counteract it, ionisation could even escalate, causing a so-called current " avalanche " which if prolonged could damage the tube.

If a poor diatomic gas quencher were introduced to the tube, the positive argon ions, during their motion toward the cathode, would have multiple collisions with the quencher gas molecules and transfer their charge and some energy to them.

If a GM tube is to be used for gamma or X-ray dosimetry measurements, the energy of each particle causing a count event must be taken into account ; however individual pulses from a G-M tube do not carry any energy information.

If it is inserted too far into the trachea ( beyond the carina ), the tip of the tracheal tube is likely to be within the right main bronchus — a situation often referred to as a " right mainstem intubation ".

If the left tube rises over the right tube, the raft is said to have flipped left over right and vice versa.

If operated from a simple power supply without current limiting, this reduction in resistance would lead to damage to the power supply and overheating of the tube electrodes.

If the circumstances are faced frankly it is not reasonable to expect this to be true.

If his dancers are sometimes made to look as if they might be creatures from Mars, this is consistent with his intention of placing them in the orbit of another world, a world in which they are freed of their pedestrian identities.

If a work is divided into several large segments, a last-minute drawing of random numbers may determine the order of the segments for any particular performance.

If they avoid the use of the pungent, outlawed four-letter word it is because it is taboo ; ;

If Wilhelm Reich is the Moses who has led them out of the Egypt of sexual slavery, Dylan Thomas is the poet who offers them the Dionysian dialectic of justification for their indulgence in liquor, marijuana, sex, and jazz.

If he is the child of nothingness, if he is the predestined victim of an age of atomic wars, then he will consult only his own organic needs and go beyond good and evil.

If it is an honest feeling, then why should she not yield to it??

If he thus achieves a lyrical, dreamlike, drugged intensity, he pays the price for his indulgence by producing work -- Allen Ginsberg's `` Howl '' is a striking example of this tendency -- that is disoriented, Dionysian but without depth and without Apollonian control.

If love reflects the nature of man, as Ortega Y Gasset believes, if the person in love betrays decisively what he is by his behavior in love, then the writers of the beat generation are creating a new literary genre.

If he is good, he may not be legal ; ;

If the man on the sidewalk is surprised at this question, it has served as an exclamation.

If the existent form is to be retained new factors that reinforce it must be introduced into the situation.

If we remove ourselves for a moment from our time and our infatuation with mental disease, isn't there something absurd about a hero in a novel who is defeated by his infantile neurosis??

If many of the characters in contemporary novels appear to be the bloodless relations of characters in a case history it is because the novelist is often forgetful today that those things that we call character manifest themselves in surface behavior, that the ego is still the executive agency of personality, and that all we know of personality must be discerned through the ego.

If he is a traditionalist, he is an eclectic traditionalist.

If our sincerity is granted, and it is granted, the discrepancy can only be explained by the fact that we have come to believe hearsay and legend about ourselves in preference to an understanding gained by earnest self-examination.

If to be innocent is to be helpless, then I had been -- as are we all -- helpless at the start.