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Time domain and frequency domain measurement techniques
No full textThe principles underlying two distinct approaches to the measurement
of electrical network characteristics over a wide frequency range are
outlined, together with brief descriptions of currently available test
systems which cover the range 0.1 - 4GHZ.
The two techniques are assessed in terms of their ultimate capabilities
with regard to accuracy, speed of measurement and costs
The temperature dependence of photo-elastic properties of cross-linked amorphous polyethylenes
No full textCross-linked samples of polyethylene were prepared by electron
irradiation of both high and low density polymers in the crystalline state.
A further cross-linked sample was obtained by curing a high density polyethylene
by reaction with dicumyl peroxide at 180°C. The stress-strain birefringence
relations were obtained, on specimens cut from these samples, at temperatures
between 130 and 250°C.
All samples showed a substantial decrease in stress-optical coefficient
with increasing degree of cross-linking and with increasing temperature. The
stress-optical properties at each temperature were extrapolated to zero degree
of cross-linking to give quantities characteristic of the Guassian network.
Comparison of these properties with Gaussian theory of the network leads to a
value of ca.1150 cals/mole for the difference in energy between trans and
gauche conformations of successive links of the polyethylene chain and also
indicates that the optical anisotropy of a - CH2 group in the elastomeric
state is more nearly given by Denbigh’s than by Bunn and Daubeny's polaris-abilities
Characteristics of the high temperature mechanisms of creep and recovery in graphite: part 2
No full text,The research reported in this document has been made possible through
the support and sponsorship of the U.S. Department of the Army throlleh its
European Research Office. This report, not necessarily in final form, is
intended only for the internal management use of the Contractor and the U.S.
Department of the Army
Some reactions of perfluoroglutaric acid
No full textPerfluoroglutaric acid when reacted with methyl magnesium iodide affords
2,6 diol 2,6 dimethyl hexafluoro pyranI in high yield and 4-one, 1,2,3
hexafluoro caproic II acid in low yield. The former material appears to exist
in a range-melting form (64-79°C) and a very labile form of melting point
96-98°C. The 2,6 diol 2,6 dimethyl hexafluoro pyranI yields a mono semi
carbazoneIII, and also a monoIV and a di 2:4 dinitro phenyl hydrazone. V
The mono 2:1l dinitrophenyl hydrazone appears to be cyclic. Reduction both
with lithium aluminium hydride and sodium borohydride yields 2,6 diol 3,4,5
hexafluoro n-heptane.VI There is evidence to suggest that reaction with
dried calcium sulphate gives 2 ene, 2 methyl 3,4,5 hexafluor 6 one cyclo-hexaneVII
Reaction with benzoyl chloride affords 2,6 dibenzoate, 2,6
dimethyl hexafluoro pyran.VIII
4 one 1,2,3, hexafluorocaproic acid was characterised as a 2:4 dinitro
phenyl hydrazoneIX and also as an S benzyl thio-uranium salt.X Infra-red
spectral evidence suggests the S benzyl thio uranium salt probably exists in
the straight chain form.
Numbers in the above text refer to the Flow Sheet, Figure 1
The effect of plastic anisotropy on flange wrinkling behaviour during sheet metal forming
No full textDuring the drawing of sheet metal between a die and a blankholder,
compressive hoop-stresses are developed which attempt to thicken or wrinkle
the flange. Previous work on this behaviour has ignored any effects due to
normal or planar plastic anisotropy. In this paper it is shown that the
blankholder pressure necessary to suppress wrinkling increases with decreasing
normal anisotropy (r) and increases with increasing planar anisotropy (AO.
The approximate plane strain conditions (daz = 0) operating in the flange can
be simulated by an edge-notched tensile specimen and this simulation demonstrates
the effect of texture hardening and softening upon flange wrinkling behaviour.
The results obtained can be interpreted valitatively by the use of anisotropic
plasticity theory.
The speed of drawing also effects wrinkling, in general, the number of
wrinkles decreases with increasing drawing speed
The reaction of perfluoroglutaric acid with methyl magnesium iodide. Part 2
No full textPerfluoroglutaric acid when treated with methyl magnesium iodide afforded
hexafluoro-2,6-dimethylpyran-2,6-diol in high yield and 2,213,3,4,4-hexafluoro-
5-oxocaproic acid in low yield. The former appeared to exist in a range
melting form (61.-79°C) and also in a very labile form melting at 96-98°C.
Problems associated with the formation of this latter form were investigated.
The hexafluoro-2,6-dimethylpyran-2,6-diol yielded a monosemi-carbazone and
also a mono and a di1(2,4-dinitrophenylhydrazone). The mono (2,4-dinitro
phenylhydrazone) appeared to be cyclic. Reduction, both with lithium aluminium
hydride and sodium borohydride yielded 3,3,4,415,5-hexafluoro-n-heptane-2,6-diol.
Reaction with anhydrous calcium sulphate gave 3,3,414,515-hexafluoro-2-
methylcyclohex-l-ene-6-one.
The acid product of the original reaction of perfluoroglutaric acid and
methyl magnesium iodide was characterised as a 2,4-dinitrophenylhydrazone and
as an S-benzylthiouronium salt. Infra-red spectroscopic evidence suggests
the latter compound exists in a straight chain form
Studies of four aspects of business in Europe
No full textPreface
The Cranfield Management Development Programme is an intensive
ten week course for middle management aged 28 - 38. The courses which
are held twice yearly started in 1964; the fourth of these, MDP 4, was
held from April - July, 1966. The members of the course are drawn from
a variety of businesses and have previous experience in one or more of
the main fields of business activity, e.g. general management, marketing,
production, finance.
As part of the course two weeks are devoted to studying business
conditions in Europe. For this tour the members are formed into snail
groups who study particular projects. Throughout the visits the
*nphasis is on discussion with Senior Executives.
The specific objectives of the European Tour are:
expose members to business problems in different European
environments and to provide an opportunity to discuss business
problems with European Managers.
To study the problems that confront British Companies who do
business in or with European countries.
To use this exposure to a new environment to effect some measure
of re-evaluation of their past business experiences in the United
Kingdom.
MDP 4 were in Europe from 13th - 24th June, 1966, during which period
the following cities were visited; Paris, Milan, Zurich, Frankfurt, and
Brussels. In each city discussions were arranged with a representative
cross-section of the business community. These included British Embassy
Staff, British Chambers of Commerce, Local. Bankers, Industrial Companies,
Advertising Agents, Trade Union Officials, Management Consultants, British
Subsidiaries and the E.E.C. Commission.
On their return from Europe a meeting was held at the Institute of
Directors in London where the members of the course presented their findings
to a group of businessmen, representatives of the Export Council for
Europe and the Confederation of British Industries.
This report is split into four parts representing the work of the
four project groups
Development of satellite telecommunications during the period 1990-2005
No full textThe global telecommunications market is in the midst of a radical restructuring program. This is driven by the desire of governments to increase competition in existing markets and of companies to diversify their service product portfolio. These changes are taking place as a result of advances in technology as well as three powerful and interconnected forces – privatisation, globalisation and liberalisation.
Introduction of new technologies in the form of Integrated Services Digital Networks ((ISDNs)and sophisticated integrated terminal equipment has resulted in the transformation of the telecommunications services market from mainly a single service industry limited by technology constraints into a multi-service industry limited by applications. As a result of privatisation and globalisation, the former national telecommunications carriers are beginning to expand overseas in order to grow. In regions where the market regulations have been liberalised, the changes have effectively shattered the highly protected and monopolistic national markets.
These changes when incorporated into the present satellite communications industry indicate a shift in traffic structure as well as in the global satellite market structure.CI
Fully discrete arbitrary-order schemes for a model hyperbolic conservation law
No full textWe investigate the fully discrete methodology and establish a formula from which
two-level explicit fully discrete arbitrary-order (both in space and time) conservative
numerical schemes for a model hyperbolic conservation law can be derived. To illustrate this approach fully discrete second, third and fourth order numerical schemes
are presented.CI
Factors influencing perceived usability and utility of LIBERTAS at Cranfield :
No full textA survey of user opinions towards and experience of Cranfield’s LIBERTAS library automation system was conducted in order to determine user attitudes towards the system, user characteristics which predict these attitudes and the key areas for improvement in service provision. The survey (n = 137) included student and staff users of the academic library and included in-library and remote access of LIBERTAS.
Two key attitudes concerned the main uses to which LIBERTAS can be put and the learning effort required for its use. The study identified that in general user perceptions of the utility and usability of the system are positive but indicate the need for improvements in system design and user education. It was found possible to predict more positive user attitudes on the basis of regularity and frequency of general system use and, in particular, use of the inter-library loan facility and certain catalogue searching facilities. However, other user characteristics such as demographic details and previous education and experience were not found to be associated with user attitudes toward the system.
Six service change areas were identified from user opinion on recommended improvements and were concerned with additional functionality, system prompts, paper-based information support, training, Boolean searching and networking. Recommendations for service improvements in each of these areas are provided and include networking LIBERTAS with CD-ROM bibliographic retrieval systems.CI