The highest efficiency of converting rest mass into energy by accreting matter into a Kerr black hole is approximately 31% (Thorne 1974). We propose a new process in which periods of accretion from a thin disk, and the associated spin-up of the black hole, alternate with the periods of no accretion and magnetic transfer of energy from the black hole to the disk. These cycles can repeat indefini...

inhalational lung diseases are among the most important occupational diseases. pneumoconiosis refers to a group of lung diseases result from inhalation of usually inorganic dusts such as silicon dioxide, asbestos, coal, etc. , and their deposition in the lungs. the resultant pulmonary disorders depend on the susceptibility of lungs; size, concentration, solubility and fibrogenic properties of t...

TABLE OF CONTENTS PAGE INTRODUCTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 333 The Color Factors of Guinea Pigs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 334 A Somatic and Germinal Mosaic (Ccd+Cdcd). . . . . . . . . . . . . . . . . . . . . . . . ...

A form of pneumoconiosis in rural African women termed "Transkei silicosis" has been thought to be due to silica particles inhaled while they are hand grinding maize between rocks. Twenty five women were studied who were considered to have this condition according to the following criteria: rural domicile, radiographic and lung biopsy evidence of pneumoconiosis, no exposure to mining or industr...