Collapse of an initially spherical vapour cavity in the neighbourhood of a solid boundary

Vapour bubble collapse problems lacking spherical symmetry are solved here using a numerical method designed especially for these problems. Viscosity and compressibility in the liquid are neglected. Two specific cases of initially spherical bubbles collapsing near a plane solid wall were simulated: a bubble initially in contact with the wall, and a bubble initially half its radius from the wall at the closest point. It is shown that the bubble develops a jet directed towards the wall rather early in the collapse history. Free surface shapes and velocities are presented at various stages in the collapse. Velocities are scaled like (Δp/ρ)^½ where ρ is the density of the liquid and Δp is the constant difference between the ambient liquid pressure and the pressure in the cavity. For Δp/ρ=10^6cm^2/sec^2 ≈ 1 atm/density of water the jet had a speed of about 130m/sec in the first case and 170m/sec in the second when it struck the opposite side of the bubble. Such jet velocities are of a magnitude which can explain cavitation damage. The jet develops so early in the bubble collapse history that compressibility effects in the liquid and the vapour are not important

Collapse of an initially spherical vapor cavity in the neighborhood of a solid boundary

Vapor bubble collapse problems lacking spherical symmetry are solved here using a numerical method designed especially for these problems. Viscosity and compressibility in the liquid are neglected. The method uses finite time steps and features an iterative technique for applying the boundary conditions at infinity directly to the liquid at a finite distance from the free surface. Two specific cases of initially spherical bubbles collapsing near a plane solid wall were simulated: a bubble initially in contact with the wall, and a bubble initially half its radius from the wall at the closest point. It is shown that the bubble develops a jet directed towards the wall rather early in the collapse history. Free surface shapes and velocities are presented at various stages in the collapse. Velocities are scaled like (Δp/ρ)^1/2 where ρ is the density of the liquid and Δp is the constant difference between the ambient liquid pressure and the pressure in the cavity. For Δp/ρ = 10^6 (cm/sec)^2 ~ 1 atm./density of water the jet had a speed of about 130 m/sec in the first case and 170 m/sec in the second when it struck the opposite side of the bubble. Such jet velocities are of a magnitude which can explain cavitation damage. The jet develops so early in the bubble collapse history that compressibility effects in the liquid and the vapor are not important

Dear Mrs. P: An Exploration in the Beliefs of High-Expectations for Individuals with Disabilities

This article is a narrative exploring the topic of self-advocacy and self-determination for individuals with disabilities. Through my narrative, I explore ways that we can increase expectations of individuals with disabilities

Standards in public life

Most liberal democracies, especially countries in the commonwealth with British traditions, are proud of their high standards in public life. Their systems of government have been developed with considerable care. Citizens in general have high expectations of their politicians and officials, and their expectations have usually been met. The occasional cause celebre has had a salutory educational affect in terms of drawing attention to dangers to be avoided, often in leading to the introduction of new procedures or safeguards, and also a contributory factor in the education of citizens about their systems of government, through focusing attention on what standards to expect and what to condemn.peer-reviewe

The Effects Of Human Disturbance On Wolves (Canis Lupus L.)

Thesis (M.S.) University of Alaska Fairbanks, 197

The sacramental worship of the reformed tradition and its music

Thesis (M.A.)--Boston University PLEASE NOTE: page 111 appears to be missing from the thesis. Our determination is that this is the result of misnumbering by the author, and no substantive content is actually missing. If you are able to determine otherwise, please contact us.From every quarter which is advocating serious reform there is a general concensus of opinion that there must be a re-examination of worship: sacramental worship must be central and it must be recognized as such. It alone fully expresses the mystery of the Incarnation, from which every Christian doctrine stems, and which, therefore, must receive primary expression in Christian worship. The closest element connected with sacramental worship is the observance of the Church Year. The place of lectionaries and the proper use of fixed forms of prayer and extemporaneous prayer must be given proper consideration. The richer forms which are being provided by the Churches give much more opportunity for congregational singing. A new field for a distinctive contribution to music is opened up by the emphasis on sacramental worship now developing. The "congregational service" and the prose Psalm provide two important fields for development. One of the most significant potentialities of the entire Church's renewed interest in sacramental worship is its relation to the Ecumenical Movement. The so-called liturgical Churches are evidencing just as vital a concern as the others in the matter of reforms in worship. It appears that the reforms being called for from all sides have something in common. It is probable that a fuller unity of Christendom shall again reveal the great Christian Sacrament in the wholeness of its many-sided glory

Blood pressure responses in healthy older people to 50 g carbohydrate drinks with differing glycaemic effects

The aim of the present study was to determine the effects on blood pressure response of 50 g carbohydrate drinks with differing glycaemic effects in ten healthy elderly subjects (age >65 years; randomized crossover design). Systolic (SBP), diastolic (DBP) and mean arterial (MAP) blood pressure, heart rate and plasma glucose levels were determined following ingestion of equal volumes (379 ml) of water and 50 g carbohydrate drinks with differing reported glycaemic indices (GI) (surrogate marker for glycaemic effect): (1) low-GI: Apple & Cherry Juice; (2) intermediate-GI: Fanta Orange; (3) high-glucose. Glucose (SBP and DBP P,0·001; MAP P¼0·005) and Fanta Orange (SBP P¼0·005; DBP and MAP P,0·001) ingestion caused a significant decrease in BP whilst blood pressure increased (SBP P¼0·008; MAP P¼0·005) from baseline following Apple & Cherry Juice ingestion. Water had no significant effect on postprandial blood pressure. Fanta Orange and Apple & Cherry Juice caused similar (P¼0·679) glycaemic effects, which were significantly greater than water, but lower than glucose (P,0·001). There was no significant correlation between the glycaemic effect of the carbohydrate drinks and there was no change in blood pressure from baseline (SBP r 20·123, P¼0·509; DBP r 20·051, P¼0·784; MAP r 20·069, P¼0·712). Apple & Cherry Juice and Fanta Orange had similar glycaemic effects, but differing effects on blood pressure. Therefore, it is unlikely that the glycaemic effect of a drink can be used to predict the subsequent cardiovascular response.Renuka Visvanathan, Richard Chen, Michael Horowitz and Ian Chapma

Headroom approach to device development: Current and future directions

OBJECTIVES: The headroom approach to medical device development relies on the estimation of a value-based price ceiling at different stages of the development cycle. Such price-ceilings delineate the commercial opportunities for new products in many healthcare systems. We apply a simple model to obtain critical business information as the product proceeds along a development pathway, and indicate some future directions for the development of the approach. METHODS: Health economic modelling in the supply-side development cycle for new products. RESULTS: The headroom can be used: initially as a 'reality check' on the viability of the device in the healthcare market; to support product development decisions using a real options approach; and to contribute to a pricing policy which respects uncertainties in the reimbursement outlook. CONCLUSIONS: The headroom provides a unifying thread for business decisions along the development cycle for a new product. Over the course of the cycle attitudes to uncertainty will evolve, based on the timing and manner in which new information accrues. Within this framework the developmental value of new information can justify the costs of clinical trials and other evidence-gathering activities. Headroom can function as a simple shared tool to parties in commercial negotiations around individual products or groups of products. The development of similar approaches in other contexts holds promise for more rational planning of service provision

Leadership in the British civil service: an interpretation

This article is essentially a polemic. The argument is that when politicians and officials now talk of ‘leadership’ in the British civil service they do not use that word in the way in which it was previously used. In the past leading civil servants, acting in partnership with ministers and within constitutional constraints, exercised leadership in the sense of setting example, inspiring confidence and encouraging loyalty. The loosening of traditional constitutional patterns, the marginalization of senior officials in the policy process and the emergence of business methods as the preferred model for public ­administration have led to a political and administrative environment in which leadership in the British civil service is now about encouraging patterns of behaviour which fit in with these changes. Leadership skills are now about ‘delivery’; they are not about motivation. It is time for politicians, officials and scholars to be open about this

Iwi interests and the RMA: An evaluation of the quality of first generation council plans

This working paper analyses the processes adopted by councils for involving hapū /iwi in plan implementation, including the resource consents process. Three topic issues were investigated to assess plan implementation — urban amenity, storm water, and issues of importance to iwi. Questions were asked about the capacity of hapū/iwi to engage in the resource consent process, which resource issues were of concern to them, their relationship with council and consent applicants, and their perception of the consent process. Most resources listed in the questionnaire were of concern to hapū/iwi, with water quality, wāhi tapu and heritage the most commonly cited. In conclusion, we found a general dissatisfaction on the part of hapū/iwi with councils’ performance with respect to both Treaty relationships and consent processing under the RMA. A further contributing factor to the poor relationships found between hapū/iwi and councils, was the lack of clarity over the role of hapū and iwi in resource management. In several districts, diverging responses from hapū/iwi and councils to questions about level of understanding and commitment suggests there is a need for more effective communication. These problems are compounded by the generally low capacity of hapū/iwi to participate in resource consent processes. These findings suggest that there is much to be done to improve relationships and behaviour of these key stakeholder groups in the plan implementation process if key provisions in the RMA related to hapū/iwi interests are to be fulfilled. The differences shown in reciprocal perceptions have serious implications for establishing a sound working partnership between councils and hapū/iwi in their areas. Making clear these discrepancies is a first step towards taking the measures needed for building a better partnership. Further, the capacity of hapū/iwi to participate could be better utilised if there was greater integration between regional and district councils on issues of significance and processes for iwi involvement