K. T. Faber Department of Materials Science and Engineering, Northwestern University Evanston, IL 60208 There is experimental evidence that stress-induced microcracking near a macrocrack tip enhances thefraclUre toughness of brittle materials. In considering the interaction of the macrocrack with multiple microcracks using a discrete model, it is essential to use approximation methods in order ...

conclusions comprehensive protection programs with on-the-job training courses for staff members are strongly recommended, as well as, the provision of radiological shields and gonad shielding protocols in radiology departments to reduce the patient’s radiation dose during radiological examinations. materials and methods a retrospective, observational cross-sectional study on the application of...

background: gonad shielding has been recommended during pelvic x-rays since the 1950s. the popular method of gonad shielding is placement a lead shield in the midline of the pelvis. the aim of this study was to evaluate the prevalence and utility of gonad shielding in pediatrics undergoing pelvic x-rays.materials and methodsfollowing study approval, we retrospectively retrieved data from the di...

results the results showed that the epoxy plates 6 and 2 mm thick had the highest and the lowest averages of shielding effectiveness at 4.48 db and 1.90 db, respectively. however, increasing the thickness was useful up to 4 mm. in addition, in a similar attenuation pattern, x-band frequency was divided into lower, middle, and upper sections. the lower section had the highest shielding effective...

The response of collisionless plasmas to an applied potential can differ from classic Debye shielding, and when the potential is rapidly applied ~‘‘instantaneous shielding’’!, the shielding can differ from when it is slowly applied ~‘‘adiabatic shielding’’!. Experiments demonstrate that when a test potential well is applied to a one-dimensional pure-electron plasma, instantaneous and adiabatic ...

................................................................................................................................... iv 1.0 Introduction ...................................................................................................................... 1 2.0 Basic Concepts in Radiation Protection and Shielding .................................................... 1 2.1 Shieldin...

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...

Uncontrolled exposure to X-band frequency leads to health damage. One of the principles of radiation protection is shielding. But, conventional shielding materials have disadvantages. Therefore, studies of novel materials, as an alternative to conventional shielding materials, are required to obtain new electromagnetic shielding material. Therefore, this study investigated the electromagnetic s...

Introduction: Unwanted exposure of ionizing radiation may result in carcinogenesis, cell mutations, and organ failure. High-atomic number elements such as lead, tungsten, bismuth have been traditionally used for radiation protection. Theoretical and practical studies have shown that a variety of shielding materials e.g. polymer composites (PCs) can be used for attenuation of th...