For superficial lesions, the electrons may be used for radiation therapy. The high energy photons and electrons are produced by a Linear accelerator (Linac). Many of electron fields need the shielding of normal or critical organs. The electron shields are usually lead slabs with few millimeter thicknesses which should be placed near the skin, less than 1 cm away from skin. In the inspection of ...

background: monte carlo simulations play a vital role in the calculation of the necessary shielding both for neutrons and photons. advanced and simple shielding materials against neutron and gamma rays were compared by simulation using the mcnb4b monte carlo code. the simulations were carried out for the three common neutron sources, namely the 252cf, the 241am/be and the dd neutron generator w...

Nowadays, fly-wire is only used for flying-related things. All plane controls depend on electronics, but they also must deal with high-intensity radiated fields. This equipment might need an electromagnetic shield to protect it from outside pollution. The current work aims develop a mesh around the operating and make better. AL6061 was create metal matrix composite. Here three combinations of M...

OBJECTIVES To assess the value of external shielding of the testis during pelvic radiotherapy. MATERIAL AND METHODS Nineteen patients, receiving radiotherapy to the pelvis with the lower border of the field at the obturator foramen, were randomly selected. A 5 half value layer cerrobent shield was positioned at the inferior border of the field. The dose to the testis was measured with and wit...

BACKGROUND In diagnostic radiology lead apron, are usually used to protect patients and radiology staff against ionizing radiation. Lead apron is a desirable shield due to high absorption and effective attenuation of x-ray photons in the diagnostic radiology range. OBJECTIVE Although lead aprons have good radiation protection properties, in recent years, researchers have been looking for alte...

The Omai intrusion-centred Au-quartz vein system, the largest Au producer presently operating in the Guyana Shield, was sampled for detailed U-Pb and Pb-Pb geochronology and petrological investigation. The age of a metavolcanic/sub-volcanic unit in the host rock sequence is 212092 Ma. Zircon analyses from the main body dioritic rocks give U-Pb ages of 209496, 2092911 and 2096+11/−10 Ma. Magmati...

Using heat shield, especially in throat area has a significant effect on combustion chamber pressure and thermal efficiency of solid fuel engines. Precise prediction of the regression of throat area for different pressures, will lead to optimal design of the motors, specifically for those of long burnout times. In this work, erosion of graphite nozzles employed in solid propellant motors with a...

3.2 Enthalpies, entropies (solid and liquid state) – free energy and entropy of mixing The heats of formation of six solid Pb-Bi alloys have been measured at 400 K in a liquid lead solution calorimeter by P. Roy, et al. They found that these alloys obey Kopp’s law of additivity and the heats of formation are therefore temperature independent. The lead and bismuth used in these experiments were ...