48,245 research outputs found
Market assessment in connection with lighter than air
A review of the marketability of the airship is given, and the relative energy consumption and speed potential of the airship is compared to other modes and guidelines to areas of initial development are also provided, together with a brief historical review
The aerospace developments concept
The viability of using airships for the transport of natural gas, and the initial design of such a system, the airship and its associated subsystems together with a continuing economic analysis of the project were investigated. Investigations, on a funded basis, were also carried out into the application of the airship for A.S.W. and A.E.W. uses, and a further investigation into the transport of mineral concentrates for an Australasian mining concern was completed
Gas ion laser construction for electrically isolating the pressure gauge thereof
The valve and the pressure gauge of a gas ion laser were electrically insulated from the laser discharge path by connecting them in series with the cathode of the laser. The laser cathode can be grounded and preferably is a cold cathode although a hot cathode may be used instead. The cold cathode was provided with a central aperture to which was connected both the pressure gauge and the gas pressure reservoir through the valve. This will effectively prevent electric discharges from passing either to the pressure gauge or the valve which would otherwise destroy the pressure gauge
Strange pulsation modes in luminous red giants
We show that the spectrum of radial pulsation modes in luminous red giants
consists of both normal modes and a second set of modes with periods similar to
those of the normal modes. These additional modes are the red giant analogues
of the strange modes found in classical Cepheids and RR Lyrae variables. Here,
we describe the behaviour of strange and normal modes in luminous red giants
and discuss the dependence of both the strange and normal modes on the outer
boundary conditions. The strange modes always appear to be damped, much more so
than the normal modes. They should never be observed as self-excited modes in
real red giants but they may be detected in the spectrum of solar-like
oscillations. A strange mode with a period close to that of a normal mode can
influence both the period and growth rate of the normal mode.Comment: 6 pages, 5 figures, accepted by MNRA
Anagram-free Graph Colouring
An anagram is a word of the form where is a non-empty word and
is a permutation of . We study anagram-free graph colouring and give bounds
on the chromatic number. Alon et al. (2002) asked whether anagram-free
chromatic number is bounded by a function of the maximum degree. We answer this
question in the negative by constructing graphs with maximum degree 3 and
unbounded anagram-free chromatic number. We also prove upper and lower bounds
on the anagram-free chromatic number of trees in terms of their radius and
pathwidth. Finally, we explore extensions to edge colouring and
-anagram-free colouring.Comment: Version 2: Changed 'abelian square' to 'anagram' for consistency with
'Anagram-free colourings of graphs' by Kam\v{c}ev, {\L}uczak, and Sudakov.
Minor changes based on referee feedbac
Causal and Stable Input/Output Structures on Multidimensional Behaviours
In this work we study multidimensional (nD) linear differential behaviours with a distinguished independent variable called "time". We define in a natural way causality and stability on input/output structures with respect to this distinguished direction. We make an extension of some results in the theory of partial differential equations, demonstrating that causality is equivalent to a property of the transfer matrix which is essentially hyperbolicity of the Pc operator defining the behaviour (Bc)0,y We also quote results which in effect characterise time autonomy for the general systems case. Stability is likewise characterized by a property of the transfer matrix. We prove this result for the 2D case and for the case of a single equation; for the general case it requires solution of an open problem concerning the geometry of a particular set in Cn. In order to characterize input/output stability we also develop new results on inclusions of kernels, freeness of variables, and closure with respect to S,S' and associated spaces, which are of independent interest. We also discuss stability of autonomous behaviours, which we beleive to be governed by a corresponding condition
Coping with bank failures: some lessons from the United States and the United Kingdom
Bank failures ; Great Britain ; Banks and banking - History
Oil imports and the fall of the dollar
Petroleum industry and trade ; Money supply
The recent U.S. trade deficit - no cause for panic
International trade ; Balance of trade
Do foreigners control the U.S. money supply?
Money supply ; Investments, Foreign
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