Active flutter control for flexible vehicles, volume 1

An active flutter control methodology based on linear quadratic gaussian theory and its application to the control of a super critical wing is presented. Results of control surface and sensor position optimization are discussed. Both frequency response matching and residualization used to obtain practical flutter controllers are examined. The development of algorithms and computer programs for flutter modeling and active control design procedures is reported

Investigation of macrocyclisation routes to 1,4,7-triazacyclononanes : efficient syntheses from 1,2-ditosylamides

Two routes to the synthesis of a cyclohexyl-fused 1,4,7-triazacyclononane involving macrocyclisations of tosamides have been investigated. In the first approach, using a classic Richman-Atkins-type cyclisation of a cyclohexyl-substituted 1,4,7-tritosamide with ethylene glycol ditosylate, afforded the cyclohexyl-fused 1,4,7-triazacyclononane in 5.86% overall yield in four steps. The second, more concise, approach involving the macrocyclisation of trans-cyclohexane-1,2-ditosamide with the tritosyl derivative of diethanolamine initially gave poor yields (< 25%). The well-documented problems with efficiencies in macrocyclisations using 1,2-ditosamides led to the use of a wider range of 1,2-ditosamides including ethane-1,2-ditosamide and propane-1,2-ditosamide. These extended studies led to the development of an efficient macrocyclisation protocol using lithium hydride. This new method afforded 1,4,7-tritosyl-1,4,7-triazacyclononanes in good yield (57-90%) from 1,2-ditosamides in a single step. These efficient methods were then applied to the preparation of a chiral cyclohexyl-fused 1,4,7-tritosyl-1,4,7-triazacyclononane (65-70%). This key chiral intermediate was then converted into a copper(II) complex following detosylation and N-methylation. The resulting chiral copper(II) complex catalysed the aziridination of styrene but it did so in a racemic fashion

THE ROLES OF MONEY IN AN ECONOMY AND THE OPTIMUM QUANTITY OF MONEY

What is the optimum quantity of money in a society? This paper answers this question both from the perspective of a utility maximizing model with real balances in the utility function, and employing an inventory theoretic model which focuses attention on the costs of transacting in different markets and on the storage costs of holding money. We find that socially optimal transactions patterns and inventory holdings can be induced by paying interest on money and bonds equal to the net rate of return on capital. This conclusion is however only valid if it is costless for the society to institute and operate such an interest payment mechanism. In a world where it is costly to institute and operate an interest payment mechanism, a social optimum requires that the rate of return on money and bonds must equal the net rate of return on capital minus the social cost of inducing individuals to hold optimal quantities of financial assets. It is therefore necessary to take account of both the potential gains in welfare from instituting interest payments on money and the real potential costs of such a policy. Reference: Economica, November, 1973 pp. 416-431

Model-free measurement of the pair potential in colloidal fluids using optical microscopy

We report a straightforward, model-free approach for measuring pair potentials from particle-coordinate data, based on enforcing consistency between the pair distribution function measured separately by the distance-histogram and test-particle insertion routes. We demonstrate the method's accuracy and versatility in simulations of simple fluids, before applying it to an experimental system composed of superparamagnetic colloidal particles. The method will enable experimental investigations into many-body interactions and allow for effective coarse-graining of interactions from simulations.Comment: 8 pages, 3 figures including supplemental materia