Transmitting medium

The characteristics of the window material will always have some effect on the temperature measurement, but the attenuation can always be corrected by preca- 

In elosing the diseussion of the transmitting medium, it is important to note that IR sensors ean only work properly when all of the following speetral ranges coincide or overlap  

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Noise Control Sound is a fluctuation of air pressure that can be detected by the human ear. Sound travels through any fluid (e.g., the air) as a compression/expansion wave. This wave travels radially outward in all directions from the sound source. The pressure wave induces an oscillating motion in the transmitting medium that is superimposed on any other net motion it may have. These waves are reflec ted, refracted, scattered, and absorbed as they encounter solid objects. Sound is transmitted through sohds in a complex array of types of elastic waves. Sound is charac terized by its amplitude, frequency, phase, and direction of propagation. 

Light is the primary carrier of photosynthetic energy and also the initial producer of natural food colorants. To speak about the color of an object is to speak simultaneously about the illuminating light source, light transmitting medium, object properties, eye sensitivity, and conventions about color scales. Teleologically viewed, food color has two ambivalent main functions ... 

Equations (17) and (22) provide the experimentalist with three knobs (see Fig. 2). First, by varying the optical density of the transmitting medium, one may alter the constant term in [Pg.155]

Alaluf M., Dror J., Dahan R. and Croitoru N., Plastic hollow fibers as a selective infrared radiation transmitting medium, J. Appl. Phys., 1992 72 (9) 3878-3883. 

A NMR probe for very high temperature and high pressure was published by Jonas in 1979 [5]. The probe had a relatively low spectral resolution but allowed NMR relaxation measurements at temperatures up to 700 °C. The pressure vessel was made from the IMI-680 titanium alloy and could withstand pressures up to 200 MPa. Because of the high temperatures attained with the probe, gaseous argon was used as the pressure transmitting medium. A first NMR relaxation study of supercritical water performed with this probe was published in 1981 [25]. 

Fig. 2. Basic principle of the diamond cell. Pressure is generated in the gasket hole when the diamonds are pushed against one another. The sample and a small chip of ruby for pressure calibration are placed in the hole and the latter is filled with a pressure-transmitting medium. The purpose of the gasket is to provide containment for the pressure medium as well as support the diamond Dais. Suitable apertures in the diamond support Mocks provide access to optical, x-ray. and other radiation...

Fig. 1. Principle of the pressuregenerating method with opposed diamond anvils. The enlargement on the right side shows the central hole of the gasket filled with rubies, a sample, and a pressure-transmitting medium.

The principle of pressure-generation with opposed diamond anvils is shown in fig. 1. A gasket with a central hole is placed between the two diamond tips to provide a sample chamber which can be filled with a pressure-transmitting medium to maintain hydrostatic conditions. Furthermore, the sample chamber is loaded with the sample and some pressure sensor. 

NaCl, which are sometimes used as the pressure transmitting medium. The unknown magnitude of the deviant stresses in such systems has often cast serious doubts on the interpretation of the measurements. 

The basic principle of the DAC is extremely simple [6,7] an anvil is made of a brilliant cut diamond with the tip cut to form a small flat part, the culet. In a DAC, two such anvils are placed in front of each other, with the culets parallel. The experimental volume is a cylindrical hole drilled in a metallic foil, the gasket. In that volume are the sample, a pressure gauge, normally a ruby chip, whose luminescence is calibrated versus pressure, and a pressure transmitting medium whose function is to ensure the stresses on the sample are as homogeneous as possible (FIGURE 2). All DACs work with the same principle. They differ only in the way the force is applied on the diamonds. 

Pressures from 1 bar to 1 kbar can be attained by using a hand-operated hydraulic piston, similar to what is used in an automobile repair shop. Above 1 kbar, pressure intensifiers can boost these pressures tenfold, reaching about 10 kbar. Both hydraulic pistons and pressure intensifiers require a hydraulic fluid (heavy oil at room temperature, n-pentane down to 77 K or so) which can be compressed isotropically for some pressures, talcum powder can act as an almost isotropic pressure-transmitting medium. If higher pressures are needed, the demand for isotropic compression must be abandoned, and anisotropies creep in. 

Fig. 8-39 Radiation system consisting of a transmitting medium between two planes...

Now consider the exchange process between surface 1 and the transmitting medium. Since we have assumed that this medium is nonreflecting, the energy leaving the medium (other than the transmitted energy, which we have already considered) is precisely that energy which is emitted by the medium... 

We now consider a simple extension of the presentations in Secs. 8-10 and 8-11 to analyze a medium where reflection, transmission, and absorption modes are all important. As in Sec. 8-10, we shall analyze a system consisting of two parallel diffuse planes with a medium in between which may absorb, transmit, and reflect radiation. For generality we assume that the surface of the transmitting medium may have both a specular and a diffuse component of reflection. The system is shown in Fig. 8-58. 

Silicon oil was used as the pressure transmitting medium. The pressure perephery is conventional and a discription can be omitted. The gauge used is of 0.1 class and hence accuracy of the pressure measurement is around 1 bar. 

For structure studies under high pressure at low temperature (HP + LT) the pressure cell must fit in a cryostat and the pressure transmitting medium must not freeze or, if it does, must not produce a large uniaxial additional component. Several combinations of devices described in Sections IV.D.l and IV.D.2 are possible. While four-circle diffractometers have been often used for room-temperature and LT structural studies of organic conductors,... 

Figure 12 Clamp made of maragin steel with Fluorinert FC 75 as pressure-transmitting medium. Inside diameter 6 mm, height 10 mm, wall thickness 25 mm, absorption 50% for a neutron wavelength of 1.175 A. (From Ref. 102.)...

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