"These cancel out your thermal signature," he said, holding them out.
Klemencig devised a form of thermal receiver depending on thermoelectricity.
The thermal G G detectors are especially useful for the purpose of quantitative measurements, because they indicate the true effective or square root of mean square value of the current or train of oscillations passing through the hot wire.
Electric-radiative circuits like thermal radiators are divided into two broad classes, good radiators and bad radiators.
The good electric radiators may be compared with good thermal radiators, such as a vessel coated with lamp black on the outside, and the bad electric radiators to poor thermal radiators, such as a silver vessel highly polished on its exterior.
- Telluriumbismuth Vacuum Thermal Detector for Electric Oscillations.
At the receiving station the differences in these systems depend chiefly upon variations in the actual form of the oscillation detector used, whether it be a loose contact or a thermal, electrolytic or magnetic detector.
- One pound of good Welsh coal properly burned in the fire-box of a locomotive yields about 15,000 British thermal units of heat at a temperature high enough to enable from 50 to 80% to flow across the boiler-heating surface to the water, the rest escaping up the chimney with the furnace gases.
Engine efficiency depends upon many variable factors, such as the cut-off, the piston speed, the initial temperature of the steam, the final temperature of the steam, the quality of the steam, the sizes of the steam-pipes, ports and passages, the arrangement of the cylinders and its effect on condensation, the mechanical perfection of the steam-distributing gear, the tightness of the piston, &c. A few values of the thermal efficiency obtained from experiments are given in Table XXI.
The thermal efficiency is therefore 185/1013 =0.183.
The way the thermal efficiency of the ideal engine increases with the pressure is exhibited in fig.
THERMOCHEMISTRY, a branch of Energetics, treating of the thermal phenomena which are associated with chemical change.
The total thermal effect, too, which is associated with the transformation, must be the same, whether the transformation is conducted directly or indirectly (Hess's Law of Constant Heat Sums), since the thermal effect depends only on the intrinsic energies of the initial and final systems.
(5) The influence of temperature on the thermal effect of a chemical action is sometimes considerable, but.
Since the initial and final temperatures, which alone determine the variation in the thermal effect, are in almost all cases within the ordinary laboratory range of a few degrees, this influence may in general be neglected without serious error.
When the solutions employed are dilute, no water is placed in the calorimeter, the temperature-change of the solutions themselves being used to estimate the thermal effect brought about by mixing them.
With knowledge then of the heats of formation of the substances involved in any chemical action, we can at once calculate the thermal effect of the action, by placing for each compound in the energy-equation its heat of formation with the sign reversed, i.e.
Thus if we wish to ascertain the thermal effect of the action Mg+CaO =MgO+Ca, we may write, knowing the heats of formation of CaO and Mg0 to be 131000 and 146000 respectively, 0-131000 = 0-146000+x x =15000 cal.
There are important mineral and thermal springs in various parts of the island.
For example, the physicist determines the density, elasticity, hardness, electrical and thermal conductivity, thermal expansion, &c.; the chemist, on the other hand, investigates changes in composition, such as may be effected by an electric current, by heat, or when two or more substances are mixed.
In the first case the thermal effect of 58.58 calories actually observed must be increased by 2d to allow for the heat absorbed in splitting off two gramme-atoms of carbon; in the second case the thermal effect of 96.96 must be increased by d as above.
It follows that the thermal effects stated above must be equal, i.e.
We assume that each carbon atom and each hydrogen atom contributes equally to the thermal effect.
If a be the heat evolved by each carbon atom, and # that by each hydrogen atom, the thermal effect may be expressed as H =na+2m/ - A, where A is the heat required to break the molecule into itsconstituent atoms. If the hydrocarbon be saturated, i.e.
Only contain single carbon linkages, then the number of such linkages is 2n - m, and if the thermal effect of such a linkage be X, then the termAisobviously equal to (2n - m)X.
By experiment it is found that the thermal effect of a double bond is much less than the effect of two single bonds, while a triple bond has a much smaller effect than three single bonds.