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Accepted Limit Values of Air Pollutants

Description: Report issued by the U.S. Bureau of Mines discussing, as stated in the introduction, the "accepted maximum permissible concentrations of air pollutants from the standpoints of health, damage to vegetation, damage to property, and requirements of industrial processes" (p. 1). This report includes tables.
Date: May 1954
Creator: Barkley, J. F.

Acid-Mine-Drainage Problems: Anthracite Region of Pennsylvania

Description: Report from the U.S. Bureau of Mines discussing the anthracite region of Pennsylvania and the efforts to prevent coal-mine drainage into nearby streams. According to the introduction, "The purpose of this report is not to develop a practicable or feasible method or process of treating acid mine water but rather to present available factual and deduced data that may be useful in showing pH range over which the treatment is to take place and the sludge products most likely to be handled" (p. 2).
Date: 1951
Creator: Ash, S. H. (Simon Harry), b. 1889; Felegy, E. W.; Kennedy, D. O. & Miller, P. S.

An Adaptive System for Process Control

Description: Abstract: Researchers at the U.S. Bureau of Mines (USBM) have developed adaptive process control systems in which genetic algorithms (GA's) are used to augment fuzzy logic controllers (FLC's). GA's are search algorithms that rapidly locate near-optimum solutions to a wide spectrum of problems by loosely modeling the search procedures of natural genetics. FLC's are rule-based systems that efficiently manipulate a problem environment by modeling the "rule-of-thumb" strategy used in human decisionmaking. Together, GA's and FLC's include all of the capabilities necessary to produce powerful, efficient, and robust adaptive control systems. To perform efficiently, such control systems require a cont element to manipulate the problem environment, an analysis element to recognize changes in the problem environment, and an adaptive element to adjust to the changes in the problem environment. The control system also employs a computer simulation of the problem environment. Details of an overall adaptive control system are discussed. A specific laboratory acid-base pH system is used to demonstrate the ideas presented; all results are from the physical laboratory system and not from a computer simulation.
Date: 1995
Creator: Karr, Charles L.; Gentry, E. J. & Stanley, D. A.

Adhesion of Diamond Films on Tungsten

Description: The U.S. Bureau of Mines has investigated the chemical vapor deposition of diamond films on tungsten substrates. The effects of deposition parameters on the adhesion of the films was determined. The films were produced using a hot filament chemical vapor deposition system. Parameters investigated were substrate temperature and methane concentration in the feed gas. Film quality, morphology, and composition were characterized by scanning electron microscopy and Raman spectroscopy. Adhesion testing was performed using an indentation technique, and the results were quantified by relating adhesion to interface fracture toughness. Diamond films with well-faceted crystalline morphology with grain size greater than 1 pm had poor adhesion properties regardless of substrate temperature or methane concentration. Diamond films with smooth morphologies consisting of rounded clusters of small (<0.2 pm) diamond crystallites and amorphous carbon phases displayed much higher adhesion, although the conditions that led to the growth of these films are not understood.
Date: 1995
Creator: Maggs, K. J.; Walkiewicz, J. W. & Clark, A. E.

Analyses of Alaska Coals

Description: Report issued by the Bureau of Mines discussing the coal fields of Alaska. Analyses of the Alaskan coal fields are presented in detail. This report includes tables, and a map.
Date: 1946
Creator: Gates, George O. & Fieldner, Arno Carl