The Rural Elderly: Providers\u27 Perceptions of Barriers to Service Delivery: Providers\u27 Perceptions of Barriers to Service Delivery

A 1989 survey of the State Units on Aging (SUAs) produced five themes that seem to underlie the many barriers to the delivery of services to the rural elderly. A systematic review of these five themes led to the identification of 34 specific challenges or barriers, which were then placed under the appropriate theme. Such a schema has been outlined in order to aid social service providers, researchers, and students in making sense of the problems faced by the increasing number of rural elderly. In addition, in order to assess the relative importance of these barriers, a second survey of 172 resource persons in the field of rural aging provided data showing, by theme, which barriers are perceived to be of most importance

Statistical analysis of electrostatic spark ignition of lean H₂/O₂/Ar mixtures

The concept of minimum ignition energy (MIE) has traditionally formed the basis for studying ignition hazards of fuels. However, the viewpoint of ignition as a statistical phenomenon appears to be more consistent with the inherent variability in engineering test data. We have developed a very low-energy capacitive spark ignition system to produce short sparks with fixed lengths of 1–2 mm, and the ignition system is used to perform spark ignition tests using a range of spark energies in lean hydrogen–oxygen–argon test mixtures used in aviation safety testing. The test results are analyzed using statistical tools to obtain probability distributions for ignition versus spark energy. A second low-energy spark ignition system was also developed to generate longer sparks with varying lengths up to 10 mm. A second set of ignition tests is performed in one of the test mixtures using a range of spark energies and spark lengths. The results are analyzed to obtain a probability distribution for ignition versus the spark energy per unit spark length. Preliminary results show that a single threshold MIE value does not exist, but rather that ignition is statistical in nature and highly dependent on mixture composition and spark length

Emittance dilution due to slow alignment drifts in the main linacs of the NLC

The tight tolerances in the main linacs of the Nest Linear Collider (NLC) result in a large sensitivity of the beam emittance to slow alignment drifts. Once the accelerator is tuned, the optimized emittances must be maintained. Slow alignments drifts will make resteering and reoptimization necessary. The frequency of these linac reoptimizations is an important parameter that determines how well the linear collider can be operated. We present simulation results that address this question for the main linacs of the NLC. We will show that the effects of alignment drifts can indeed be handled

Choral reading

Thesis (Ed.M.)--Boston Universit