Direct-beam radiation

Concentrating solar collector systems that utilize the direct beam radiation would be more likely deployed in areas with relatively low aerosol optical depth, to maximize direct beam utilization.13... 

For the atmosphere the angle 0 is the solar zenith angle, for direct beam radiation. As the atmosphere is spherical and not plan-parallel, the path length of the radiation through the atmosphere has to be described by the relative atmospheric mass m, which can be approximated for zenith angles less than about 85° by... 

Direct Beam Radiation - Solar radiation that arrives in a straight line from the sun. 

The GAMMASCAN 1500 HR is a combined system for two-dimensional (2D-CT) and three-dimensional (3D-CT) computed tomography, as well as digital radiography (DR). The system is equipped with two separate detector systems for the fan-beam and cone-beam CT. The sire of the objects is limited to a height of four meters, maximum diameters of 1.5 meters and a weight of up to 15 tons. The turntable which carries the test samples can be moved along and across the beam direction ( X- and Y- direction). The radiation source and the detector systems can be moved in Z- direction, both, simultaneously and independently. 

T he total or global solar radiation has a direct part (beam radiation) and a diffuse part (Fig. 11.31). In the simulation, solar radiation input values must be converted to radiation values for each surface of the building. For nonhorizontal surfaces, the diffuse radiation is composed of (a) the contribution from the diffuse sky and (b) reflections from the ground. The diffuse sky radiation is not uniform. It is composed of three parts, referred to as isotropic, circumsolar, and horizontal brightening. Several diffuse sky models are available. Depending on the model used, discrepancies for the boundary conditions may occur with the same basic set of solar radiation data, thus leading to differences in the simulation results. 

The use of nuclear techniques for the detection of buried expls (in mines) has been investigated by the US Army over the past 25 years. The basic approach is the use of a direct beam of highly penetrating radiation to irradiate the soil and the measurement of a reflected, scattered, induced or secondary signal to indicate the presence of a buried mine. A complete historical review and analysis of this work has been prepared by Coleman et al (Ref 18), A brief summary of the highlights of the overall effort is provided here... 

In most instances, external-beam radiation therapy used in conjunction with breast-conserving procedures involves 4 to 6 weeks of radiation therapy directed to the breast tissue to eradicate residual disease. Complications associated with radiation therapy to the breast are minor and include reddening and erythema of the breast tissue and subsequent shrinkage of total breast mass beyond that predicted on the basis of breast tissue removal. Some clinical situations also require postmastectomy radiation therapy as well (see section on locally advanced breast cancer). 

Cationic cured epoxies may also be crosslinked by electron beam radiation. A major application for this technology is the repair of composite aerospace structures. Direct benefits of EB processing include rapid cure, allowing completion of a permanent repair in the same or less time than a traditionally temporary repair, and ease of material handling. Other... 

For modem crystal diffraction studies, a nearly monochromatic beam of X-rays is required. This may be achieved by using a crystal monochromator. The direct beam from the X-ray tube is reflected from a large crystal in such a way as to give a very narrow (almost monochromatic) beam. This technique will become easier to explain after we have discussed diffraction procedures. Another method in common use is that of filtering. We wish to use only the Ka wavelengths in a diffraction experiment because they are the most intense. A metal absorber is placed in front of the beam which absorbs the unwanted radiation. Absorption of X-rays follows the... 

Baldacchino G, Le Parc D, Hickel B, Gardes-Albert M, Abedinzadeh Z, Jore D, Deycard S, Bouffard S, Mouton V, Balanzat E. (1998) Direct observation of H02/02- free radicals generated in water by high LET pulsed heavy ion beam. Radiat Res 149 128-133. 

Figure 8.9. Relative flux density in a thick target (a) beam from one direction (b) radiation field.

The daytime temperature profiles were easy to interpret, as done above, but the nighttime profiles did not have a simple interpretation. Sunlight impinges on the forest as a directed beam, some of it penetrates the canopy, especially with almost overhead sun. Day and night, heat radiation is emitted by all surfaces and in all directions, and radiatively cooled leaves chilled adjacent air, which sank toward the groimd. The net effect in our examples was that there was a minor temperature inversion throughout the forest... 

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