Raman studies of tribological model systems

The purpose of this study was to explore tribological model systems. Specifically, the types of molecular forces a chemical bond will undergo while under tribological stress. While tribology has been a growing field of interest, many of the studies have focused on the mechanical conditions while few have considered the chemical wear and tear. Tribological forces are generally mechanical in nature, but molecules undergoing these mechanical force changes are known to change their respective vibrational frequencies or break apart and form derivatives. In this study directly, molecular bonds of different types have been investigated by Raman spectroscopy under different types of shear stress. The different types of shear stress included compression, stretching, and elongation. While suggestions are given about the next step in the formation of molecular derivatives, the main thrust of the study has been to focus and explain the molecular bond changes as a function of tribological shear stress

Suicide in Australian farming, 1988-1997

Objectives: To identify and describe suicide data for occupational classifications relating to farm managers and agricultural labourers for Australia for the period 1988 to 1997, and to relate resultant suicide rates to farmers' terms of trade. Method: Descriptive and linear regression analysis of aggregated mortality data. Results: In the period 1988 to 1997, 921 suicides were identified. The majority of these suicides were farm managers (67.4%). Farm manager suicides occurred predominantly in older age groups (55 + years). In comparison agricultural labourer suicides were younger, with the majority of suicides occurring in the 15-39 years age group. The most common methods for both groups were firearms (particularly hunting rifles and shot guns), hanging and motor vehicle exhaust gas. These methods accounted for approximately 81% of all male farm suicides. Firearms accounted for 51% of male farm suicide, in comparison to 23% for the wider Australian male population for the same period. Estimated age standardized rates per 100 000 for male farm managers for the 10-year period ranged from 24.8 to 51.4. For male agricultural labourers these rates ranged from 23.5 to 41.9. Analyses also revealed a negative correlation (r=-0.75,

Towards a practical parallelisation of the simplex method

Linear programming, Simplex method, Sparse, Parallel computing, 90C05,