Radiation Sources surfaces

For pipelines in service in chemical plants, it is not usually convenient to place a radiation source inside the pipe and position it to irradiate each welded joint. The radioisotope source container maybe placed on the outer surface of the pipe. The radiation beams then pass through two pipe wall thicknesses to expose films placed diametrically opposite the radiation source, also on the outside of the pipe wall. Other methods, such as magnetic particle inspection of welds in steel pipe, or ultrasonic inspection of welds in pipes of all materials, supplement x-rays in many critical appHcations. The ultrasonic tests can often detect the thin, laminar discontinuities parallel to the pipe surface or the incomplete fusion discontinuities along the weld... 

The effect of radiation-source temperature on the low-temperature absorptivity of a number of additional materials is presented in Fig. 5-12. It will be noted that polished aluminum (cui ve 15) and anodized (surface-oxidized) aluminum (cui ve 13), representative of metals and nonmetals respectively, respond oppositely to a change in the temperature of the radiation source. The absorptance of surfaces for solar... 

ReflEXAES can be used for near-surface structural analysis of a wide variety of samples for which no other technique is appropriate. As with EXAES, ReflEXAES is particularly suited for studying the local atomic structure around particular atomic species in non-crystalline environments. It is, however, also widely used for the analysis of nanocrystalline materials and for studying the initial stages of crystallization at surfaces or interfaces. ReflEXAES was first proposed by Barchewitz [4.135], and after several papers in the early nineteen-eighties [4.136, 4.168-4.170] it became an established (although rather exotic) characterization technique. Most synchrotron radiation sources now have beam-lines dedicated to ReflEXAES experiments. 

The distribution of solar radiation, including surface radiation exchange, can account for solar heat source variations in time and local space. 

It is assumed that the target surface faces toward the radiation source so that it receives the maximum incident flux. The rate of combustion depends on the release. For a pool fire of a fuel with a boiling point above the ambient temperature (Tg), the combustion rate can be estimated by the empirical relation ... 

If the emissive power E of a radiation source-that is the energy emitted per unit area per unit time-is expressed in terms of the radiation of a single wavelength X, then this is known as the monochromatic or spectral emissive power E, defined as that rate at which radiation of a particular wavelength X is emitted per unit surface area, per unit wavelength in all directions. For a black body at temperature T, the spectral emissive power of a wavelength X is given by Planck s Distribution Law ... 

Modem instrumentation has improved substantially in recent years, which has enabled the measurement of XPS spectra of superior resolution necessary to reveal the small BE shifts present in highly covalent compounds such as those studied here. In a laboratory-based photoelectron spectrometer, a radiation source generates photons that bombard the sample, ejecting photoelectrons from the surface that are transported within a vacuum chamber to a detector (Fig. 2). The vacuum chamber is required to minimize the loss of electrons by absorption in air and, if a very high quality vacuum environment is provided (as is the case with modem instruments), the surface contamination is minimized so that the properties of the bulk material are more readily determined. 

High radiation area Accessible area where radiation levels could allow an individual to receive a dose equivalent in excess of 0.1 rem (1 mSv) in 1 hour at 30 centimeters from the radiation source or from any surface the radiation penetrates. 

If flame radiation occurs in the mass burning process—or any other radiation is imposed, as is frequently the case in plastic flammability tests—one can obtain a convenient expression for the mass burning rate provided one assumes that only the gasifying surface, and none of the gases between the radiation source and the surface, absorbs radiation. In this case Fineman [32] showed that the stagnant film expression for the burning rate can be approximated by... 

Emission infrared spectroscopy is used for thin films and opaque polymers. The sample is heated so that energy is emitted. The sample acts as the radiation source and the emitted radiation is recorded giving spectra similar to those of classical FTIR. In some cases, IR frequencies vary because of differences in the structures at different depths and interactions between surface and interior emissions. 

The SEXAFS teehnique is a partieular surface sensitive detection mode applied to an EXAFS measurement, performed in a particular environment, the Ultra High Vacuum, which is needed in order to prepare and protect the atomic-scale eleanliness of surface and interface systems for the whole time length of the experiment. As such the technique borrows equipment and procedures from the surface science spectroscopies, and exploitation procedures of the synchrotron radiation source from the conventional, non vacuum, EXAFS method. The studies described below have been performed at the Laboratoire pour T Utilisation du Rayonnement Electro-magnetique (LURE) exploiting synehrotron radiation from the storage ring DCI... 

The possibility of a continuous variation of the radiation beam energy is the main advantage of a synchrotron radiation source with respect to this surface vs. bulk problem. 

Chemical composition of fresh HTs was determined in a Perkin Elmer Mod. OPTIMA 3200 Dual Vision by inductively coupled plasma atomic emission spectrometry (ICP-AES). The crystalline structure of the solids was studied by X-ray diffraction (XRD) using a Siemens D-500 diffractometer equipped with a CuKa radiation source. The average crystal sizes were calculated from the (003) and (110) reflections employing the Debye-Scherrer equation. Textural properties of calcined HTs (at 500°C/4h) were analyzed by N2 adsorption-desorption isotherms on an AUTOSORB-I, prior to analysis the samples were outgassed in vacuum (10 Torr) at 300°C for 5 h. The specific surface areas were calculated by using the Brunauer-... 

Catalysts were characterized by means of X-ray diffraction (Phillips diffractometer PW3710, with CuKa as radiation source), UV-Vis-DR spectroscopy (Perkin-Elmer Lambda 19) and chemical analysis. Measurements of surface acidity were carried out by recording transmission FT-IR spectra of samples pressed into self-supported disks, after adsorption of pyridine at room temperature, followed by stepwise desorption under dynamic vacuum at increasing temperature (Perkin-Elmer mod 1700 instrument). The procedure for chemical analysis is described in detail in ref. (13). 

The distance between the radiation source and the PMMA slab surface is large enough so that the radiation field approximates an aligned and expanded field (ICRU, 1992). An anterior to posterior radiation condition is simulated. The central ray of the radiation field is perpendicular to the center of the PMMA slab. Multiple personal monitors are irradiated to obtain information on accuracy and precision. Irradiation of the personal monitors using fields incident at nonperpendicular angles is used to examine differences from the response to the perpendicular irradiation. 

Okamura, S., T. Iwasaki, Y. Kobayashi, and K. Hayashi Gamma-ray initiated graft copolymerization on the surface of nylon fibers and in the inner layers of cellulosic fibers. Large Radiation Sources in Ind., Proc. Conf., Warsaw, 1959, 1, 459. 

There are two categories of remote sensing, active and passive. Passive techniques utilise electromagnetic radiation emitted from or transmitted through the atmosphere, the radiation source being for example the black body emission from the earth s surface or solar and stellar irradiances. The most critical part of a passive remote sensing instrument is its detector. In contrast, active remote sensing systems have their own radiation source and a detector, for example, radar and lidar techniques. 

The XPS spectra were recorded on a Surface Science Laboratories small spot system using a monochromatized A1K X-ray radiation source. The take-off angle used for these measurements was 35°. Full details of the methods used in interpreting the XPS data have been described elsewhere [14], Data reduction was done using Surface Science Laboratories software version 8.0. This software utilizes a least squares curve fitting approach with only chi square statistics for goodness of the calculated fit to the experimental data. 

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