Servo-controlled decoupler eliminates oscillations in fluid flow - A concept

Active control technique, using accelerometer-controlled servovalve to operate a compensating piston, effectively eliminates pressure fluctuations due to longitudinal structural vibration within a relatively long bandwith

Equation relates flow at free jet to flow downstream

Nonlinear equation relates the flowrate at an orifice to that at a station downstream from the orifice. This equation should aid in understanding combustion instabilities and should not be subject to the substantial errors of prior analytical methods

Accumulator

An accumulator particularly adapted for use in controlling the pressure of a stream of fluid in its liquid phase utilizing the fluid in its gaseous phase was designed. The accumulator is characterized by a shell defining a pressure chamber having an entry throat for a liquid and adapted to be connected in contiguous relation with a selected conduit having a stream of fluid flowing through the conduit in its liquid phase. A pressure and volume stabilization tube, including an array of pressure relief perforations is projected into the chamber with the perforations disposed adjacent to the entry throat for accommodating a discharge of the fluid in either gaseous or liquid phases, while a gas inlet and liquid to gas conversion system is provided, the chamber is connected with a source of the fluid for continuously pressuring the chamber for controlling the pressure of the stream of liquid

Space Shuttle Main Engine (SSME) Pogo testing and results

To effectively assess the Pogo stability of the space shuttle vehicle, it was necessary to characterize the structural, propellant, and propulsion dynamics subsystems. Extensive analyses and comprehensive testing programs were established early in the project as an implementation of management philosophy of Pogo prevention for space shuttle. The role of the space shuttle main engine (SSMF) in the Pogo prevention plans, the results obtained from engine ground testing with analysis, and measured data from STS-1 flight are discussed

POGO Instabilities Suppression Evaluation

A dynamic (frequency response) analysis was made of a liquid oxygen feed system consisting of a low-speed inducer, a high-speed main pump and a positive displacement pulser utilized for simulating pogo induced pressure oscillations. Based on the results of the analysis, an active control system for suppression of pulser generated pressure oscillations was designed, fabricated and tested. The test results verified that the suppressor was effective in attenuating the generated pressure oscillations over the frequency range from 10 to 30 Hz

Pre-operative optimisation employing dopexamine or adrenaline for patients undergoing major elective surgery: a cost-effectiveness analysis

<b>Objective</b>: To compare the cost and cost-effectiveness of a policy of pre-operative optimisation of oxygen delivery (using either adrenaline or dopexamine) to reduce the risk associated with major elective surgery, in high-risk patients. <b>Methods</b>: A cost-effectiveness analysis using data from a randomised controlled trial (RCT). In the RCT 138 patients undergoing major elective surgery were allocated to receive pre-operative optimisation employing either adrenaline or dopexamine (assigned randomly), or to receive routine peri-operative care. Differential health service costs were based on trial data on the number and cause of hospital in-patient days and the utilisation of health care resources. These were costed using unit costs from a UK hospital. The cost-effectiveness analysis related differential costs to differential life-years during a 2 year trial follow-up. <b>Results</b>: The mean number of in-patient days was 16 in the pre-optimised groups (19 adrenaline; 13 dopexamine) and 22 in the standard care group. The number (%) of deaths, over a 2 year follow-up, was 24 (26%) in the pre-optimised groups and 15 (33%) in the standard care group. The mean total costs were EUR 11,310 in the pre-optimised groups and EUR 16,965 in the standard care group. Life-years were 1.68 in the pre-optimised groups and 1.46 in the standard care group. The probability that pre-operative optimisation is less costly than standard care is 98%. The probability that it dominates standard care is 93%. Conclusions: Based on resource use and effectiveness data collected in the trial, pre-operative optimisation of high-risk surgical patients undergoing major elective surgery is cost-effective compared with standard treatment

Linear force and moment equations for an annular smooth shaft seal perturbed both angularly and laterally

Coefficients are derived for equations expressing the lateral force and pitching moments associated with both planar translation and angular perturbations from a nominally centered rotating shaft with respect to a stationary seal. The coefficients for the lowest order and first derivative terms emerge as being significant and are of approximately the same order of magnitude as the fundamental coefficients derived by means of Black's equations. Second derivative, shear perturbation, and entrance coefficient variation effects are adjudged to be small

Transgressive Possibilities in Post-Corporate Enterprise Culture

No abstract available

Deconstructing and reconstructing 'best interests': deciding for legally incompetent patients

'Best interests' is a panacea within medico-legal decisions for incapacitated patients. Its scope is extensive and its range of application situationally diverse, yet the meaning of best interests remains relatively obscure. To clarify its character this thesis deconstructs best interests by critically examining current law regarding treatment decisions for incompetent patients (Chapters 1 and 2). The conceptual implications of using 'interests' are then considered through exploration of philosophical approaches to sources of interests (Chapter 3). Certain important distinctions are raised and the notion of an 'interest network' is mooted. The possibilities for reconstruction of best interests are considered in Chapters 4 and 5. The importance of autonomy, including competence construction and patient perspective in alternative decision-making mechanisms, is considered. The meaning of welfare, together with quality of life and personhood are also explored in the context of incapacitated persons. Reconstruction then begins in earnest. 'Respect' is proffered as the most suitable ethic for governing 'best interests'. A new synthesis of respect is developed through Chapters 6,7 and 8. It is argued (Chapter 6) that we should admit a wider range of interests, recognise the importance of relationship, and differentiate between input and decision-making authority. A 'whole life, over time' approach is proffered in Chapter 7, including a reclassification of incompetence, and a process for ascertaining interests outlined. The final chapter embraces ethical issues, conflict resolution and criteria for justified decision-making. Discussion concludes by developing a normative framework to legally represent the improved respect synthesis within 'best interests'