Luminance output

Densities of the fuel, oxidizer and other ingredients decide the densities of formulations. Density of the formulation determines its weight that can be accommodated in a particular volume. The density becomes one of the important criteria in ammunition where specified performance in terms of burning time, delay or luminous output is required in a limited space or column. 

Some of the conditions to be satisfied by phosphor material are (i) the phosphor should absorb at the emission wavelength of the diode, (ii) the quantum yield should be high and (iii) the full width at half maximum of the emission band should be small to achieve high luminous output. Some of the promising phosphor systems containing Eu3+ and Tb3+... 

Figure 2 gives some of the basic terms of optical power. These terms refer to the total radiant output of a light source expressed in watts (radiometric) and total luminous output in lumens (photometric), the most basic units of optical flux. 

Elimination of conventional mask transmission loss, which reduces the electron beam-to-luminance efficiency of the shadow mask tube, permits the Trinitron to operate with significantly greater luminance output for a given beam input power. 

Misalignment and misregistration of the three beams of the color CRT will lead to loss of purity for colors produced by combinations of the primary colors. Such reproduction distortions can also result in a reduction in luminance output because a smaller part of the beams are passing through the apertures. Additional errors that must be considered include... 

Luminous Output Contrast Ratio at Ambient Resolution... 

Thus, for a given projector luminance output, viewed brightness varies in proportion to the reciprocal of the square of any screen dimension (width, height, or diagonal). An increase in screen width from the... 

Highly directional luminance output for efficient optical coupling... 

Chromatographic agents, solvents, and samples can frequently reduce the luminous output produced by interactions between the radioactive sample and the fluor of the scintillation fluid. This effect, known as quenching, directly reduces the counting efficiency of the system and can result in significant quantitation errors if not taken into account. In addition to quenching, other interfering processes such as chemiluminescence, phosphorescence, and efficiency losses due to self-adsorption of labeled compounds on the TLC adsorbent can affect quantitative measurement (5,49,50,51). 

Example An Incandescent Bulb Consider a 100-W incandescent bulb. If all of its power were made available as radiation at 0.55 pm, each watt would generate 692 lumens, or a total of 69,200 lumens. Bulb manufacturers now state the luminous output of their bulbs on the package typical values are around 1700 lumens for a 100-W incandescent bulb. Thus the efficiency is about 1700 divided by 69,200, or 2.5%. The rest of the power goes into that portion of the spectrum to which the eye does not respond, and into heating the space around the bulb. ... 

Light. Light level, or illuminance, is usually measured with a photocell made from a semiconductor such as silicon. Such photocells produce an output current proportional to the illumination on the sensor incident luminous density. 

The mechanism of radiative transfer in flares was found to depend on compn, flare diameter and pressure (Ref 69). The flare efficiency calcn is complicated by the drop-off in intensity at increasing altitudes and at very large diameters owing to the lower reaction temps (Ref 11, p 13) and the narrowing of the spectral emittance band (Ref 35). The prediction of the light output in terms of compn and pressure (ie, altitude) is now possible using a computer program which computes the equilibrium thermodynamic properties and the luminance (Ref 104) Flare Formulations... 

Photoflash compns containing Hf and K perchlorate possess greater luminous efficiency on a volume basis than do other formulations (Ref 128). Zr, for example, when burned in oxygen has an average color temp of 4883°K compared with 5235°K for Hf when measured at peak intensity (Ref 65). In pyrotechnic flash units, substitution of Al with Hf and Ti produced comparable peak output, but inferior output... 

To achieve the discharge, a 60-cycle, 110-volt luminous-tube transformer with an output rating of 10,000 to 15,000 volts is adequate. The output potential is best controlled by activating... 

The luminous efficiency is the simplest to calculate. It is the ratio of the luminance (cd/m2) to the current density (A/m2), and has units of cd/A. Finally, the power efficiency is the ratio of the light output in lumens divided by the electrical input in watts. For reference, a typical incandescent light bulb is 151m/W, while a fluorescent light bulb is 601m/W. 

Venous tone regulates the volume of blood returned to the heart, hence, stroke volume and cardiac output. The luminal diameter of the arterial vasculature determines peripheral resistance. 

Elements and molecules emit and absorb photons with characteristic energies. As a result, measurements of stars, comets, or other luminous bodies with a spectrograph, which permits the output to be measured as a function of wavelength, reveal numerous emission or absorption lines (Fig. 4.1). These lines can be used to infer the compositions of the objects. The first spectroscopic measurements of the Sun, stars, and other luminous objects were made in the last half of the nineteenth century. However, it wasn t until the late 1920s that relatively accurate elemental abundances for the Sun and the stars were determined (see Box 4.1). 

In the optoelectronic X-ray image intensifier (Fig. 86), [5.427], the X-ray phosphor screen (input screen) is in direct optical contact with a photocathode that converts the luminance distribution of the X-ray screen into an electron-density distribution. The liberated electrons are accelerated in an electric field between the photocathode and an anode (20-30 kV) and are focused by electron lenses onto a second phosphor screen (output screen), where conversion of the electron image to a visible image takes place. 

A very important application of the heats of reaction is the calcn of the reaction temp of propints which determine in part the ballistic performance. Heats of reaction also permit the calcn of the adiabatic reaction temp of pyrot reactions which are of value in judging the luminous yield of flares as well as the heat output of thermite reactions... 

In optical pyrometry the size of the luminous object must meet a certain minimum, and the radiant energy output must be uniform over the area observed, lest the apparent temp be low. Moreover, temp readings will be low if radiant energy is absorbed in the colder outer gas envelope. The role of smoke and other debris in the study of expls was alluded to in an earlier article ( Spectroscopy of Energetic Materials in this Vol). There, too, was referenced rapid scan spectroscopy for the resolution of pyrot phenomena, and of the energetics of fuel-air expins. For more extensive discussions of high temp measurement techniques, see Ref 6a... 

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