There is archaeological evidence that coal was used in the Bronze Age, 3,000-4,000 years ago, in ancient China and in Roman Britain. But over the millennia, while human and animal labour and wood burning were the principal energy sources, coal played a minor role. In the pre-industrial age, reflected in the novels of Thomas Hardy and the paintings of the Old Masters, energy supply was local and...

This paper explores a reliability based heuristic mathematical model for basic and classical age replacement policy. Using new model, optimal preventive age replacement policy is determined to maximize system reliability. For special systems having exponential density function with constant hazard function, a different simple decision-making model is proposed. A case study of two industrial mac...

Background: Leukemia is a growing disease. The risk factors such as parental age, cousin marriage, exposure to pesticides and radiation, parental smoking, breastfeeding, and the number of older siblings are suggested as the risk factors for childhood leukemia. Objective: To evaluate the possible risk factors for childhood leukemia, including environmental, parental, genetic and other factors. M...

healthy hire effect (hhe) is considered as an epidemiological phenomenon, complicating the assessment of a true cause - effect relationship between occupational exposure and health status of workers. the current study was aimed at identification and elimination of hhe in the risk assessment of arterial hypertension (ah) in coal miners. overall, 1553 miners, working in west siberia, were enrolle...

in industries, in general, occurrence of accidents is not negligible in which injure the workforce and burden cost to society. the main purpose of this study was investigation of industrial accidents and their trend in fars province. this is a descriptive analytical retrospective study in which data on industrial accidents were collected from the labor organization of fars province during years...

Despite the well-known economical, technical, and environmental benefits achieved by the use of the blended cements, its production has been slow to develop in the U.S.. The major aim of this project was to establish blended cement production technology through laboratory investigations. This involved production and evaluation of blended cement in the laboratory, in order to define materials, p...