Search Results

You are looking at 1 - 3 of 3 items for :

  • Author or Editor: P. Harper x
  • Chemistry and Chemical Engineering x
  • Refine by Access: All Content x
Clear All Modify Search

Abstract  

Monte Carlo calculations were done to simulate the decay of80mBr in order to estimate the energies and distribution of Auger and Coster-Kronig electrons emitted in this de-excitation process. Results show that for an isolated atom, the average number of electrons emitted per decay is 6.926 and 8.016 for an atom in the condensed state. These values agree well with experimental results of Wexler and Anderson. The average calculated electron energies were 1122 eV and 991 eV with ranges of 8.02 A° and 6.71 A° in unit density matter for the isolated an condensed states, respectively. These results will be used to estimate localized energy deposition which will be correlated to the radiotoxic effects of80mBr-bromo-deoxyuridine as measured in experiments currently underway in our laboratory using cell cultures. Our aim is to assess the radiotoxicity of low energy, short range electrons for its eventual use in cancer therapy.

Restricted access

Abstract  

Used lubricating oil analysis programs are currently employed by both the military and industry in an attempt to minimize some of the costs associated with equipment failure. The periodic determination of water elements in the lubricant of an oil-wetted system can provide very useful information on the condition or health of the system and an early indication of impending failure. In the present study, the application of Neutron Activation Analysis (NAA) to used oil analysis was investigated. The method developed allowed for the determination of fifteen elements (Ag, Al, Cl, Cr, Cu, Fe, In, Mg, Mn, Mo, Na, Ni, Sn, Ti and Zn) associated with engine wear or deterioration. Results obtained for the analysis of used naval diesel oils exhibited good agreement with results obtained by Atomic Absorption Spectrophotometry (AAS) methods. A drawback of the NAA procedure is that the determination of Fe, a major wear element in most systems, involves an analysis time of approximately one week.

Restricted access

Abstract  

The increasing trend towards the use of fine oil filtration in modern jet engines suggests that the Spectrometric Oil Analysis Program (SOAP), which routinely monitors the health of aeroengines, may no longer be effective in detecting abnormal wear trends. Since the oil filter contains a wealth of information on wear in a system, it may be necessary to perform engine health monitoring through Filter Debris Analysis (FDA). In the present study, a method was developed for the determination of 19 wear elements (Ag, Al, Au, Cd, Co, Cr, Cu, In, Fe, Mg, Mn, Mo, Ni, Sb, Sn, Ti, V, W and Zn) in aircraft engine oil filter debris samples using the analytical technique of Neutron Activation Analysis (NAA). Results obtained by NAA for the analysis of two types of filter debris samples compared well with results obtained previously for similar samples and it appears that FDA should be very useful for following wear trends.

Restricted access