Phase Coherence in Multiple Pulse Optical Spectroscopy

In this paper we describe a new technique for the generation of multiple pulse phase coherent sequences in optical spectroscopy. The technique is an extension of the acousto-optic modulation and fluorescence detection methods developed for optical transitions by Zewail and Orlowski (Zewail et al., Chem. Phys. Lett. 48, 256 (1977); Orlowski et al., Chem. Phys. Lett. 54, 197 (1978)). Application of these multiple pulse trains (of different phases) to optical transitions of two-level and multilevel systems is demonstrated experimentally. It is shown that they can be used to (i) suppress spontaneous emission background, (ii) enhance coherent transients such as photon echoes, (iii) measure additional relaxation parameters in systems with complex rotational-vibrational levels, and (iv) enhance the effective laser bandwidths through composite pulse trains, as demonstrated on I2 gas. Finally, the potential of this development is extended to the possibility of observing selective multiquantum excitation in molecules

Studies of Impaired People in Paddock Wood

This volume contains three reports based on a community survey of impaired persons living in and around Paddock Wood, Kent and who were registered with a general medical practice of three partners working with nurses, health visitors and ancillary workers from a purpose-built health centre. The opportunity of working with a primary medical care team enabled a number of different questions to be examined, and because some of these form discrete areas of interest the results are presented in the following three papers:- Identifying Handicapped People in a General Practice Population. Interview Surveys of Handicapped People. The Accuracy of Statements about the Underlying Medical Conditions Handicapped People in Paddock Woo

Modeling Evolving Coronal Loops with Observations from STEREO, Hinode, and TRACE

The high densities, long lifetimes, and narrow emission measure distributions observed in coronal loops with apex temperatures near 1 MK are difficult to reconcile with physical models of the solar atmosphere. It has been proposed that the observed loops are actually composed of sub-resolution ``threads'' that have been heated impulsively and are cooling. We apply this heating scenario to nearly simultaneous observations of an evolving post-flare loop arcade observed with the EUVI/\textit{STEREO}, XRT/\textit{Hinode}, and \textit{TRACE} imagers and the EIS spectrometer on \textit{HINODE}. We find that it is possible to reproduce the extended loop lifetime, high electron density, and the narrow differential emission measure with a multi-thread hydrodynamic model provided that the time scale for the energy release is sufficiently short. The model, however, does not reproduce the evolution of the very high temperature emission observed with XRT. In XRT the emission appears diffuse and it may be that this discrepancy is simply due to the difficulty of isolating individual loops at these temperatures. This discrepancy may also reflect fundamental problems with our understanding of post-reconnection dynamics during the conductive cooling phase of loop evolution.Comment: Revised version submitted to ApJ in response to referee's comment

A study of Massachusetts Society for the Prevention of Cruelty to Children referrals to the Judge Baker Guidance Center, 1938-1939

Thesis (M.S.)--Boston University, 194

Development and mathematical analysis of a modular CNG valve : a thesis presented in partial fulfilment of the requirements for the degree of Master of Engineering, Mechatronics, at Massey University

With the rising cost of oil and uncertainty of supply, there has never been a greater opportunity to offer an alternative fuel into the automotive market than at this present time. Compressed natural gas (CNG) and liquid petroleum gas (LPG) are popular alternatives, producing less green house gasses after the combustion process that add to the raising global warming concern. With high performance fuel injected state of the art engines used in the majority of the late model vehicles, the problem when running on CNG or LPG is poor control of the air/fuel ratio throughout the engine's speed and load range using the conventional zero pressure regulator and mixer combination gas conversion equipment used previously for carburetted engines. This problem is completely eliminated with gas injection system. The Harrison CNG Electronic Gas injection System control valve is a linear proportional valve. Testing on the valve has found that the response is linear under all operating conditions; however the valve exhibits occasional instances of hysteresis. Due to this unfortunate characteristic further analysis is required, in the form of a mathematical analysis, to determine the exact causes of this problem. Another point of concern is the complexity of the valve, due to the many moving parts, this results in high production costs and increased reliability concerns. This masters project will include the mathematical analysis of the current Harrison CNG Electronic Gas injection system, further testing and refinement. The objective is to produce a modular system that can be retrofitted to any make of vehicle. Research will be directed in the development of mathematical equations to analyse valve operation for improvement of operation, to increase performance the valve will be redesigned to reduce complexity and ready it for production. The valve will be tested on a variety of vehicles from a 2 litre sedan to a 5.8 litre diesel engine that has been converted to operate on CNG, to prove the versatility of the valve and its ability to tailor the engine torque curve to that required for the vehicles unique operating requirements