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C.V.D. annual report: January, 1967 research project ru27-1 : analogue study of semiconductor device structures
No full textThe e::tension of the resistance network analogue method to the study
of a M.O.S.T. structure is described. By means of an iterative technique,
data regarding channel current, field distribution, surface charge and
position of pinch-off point as function of gate and drain voltagen can be
obtained which do not involve the usual 'gradual' channel approximation
Results for a particular device geometry are presented.
A discussion of a digital computer approach to the solution of semiconductor
device current flow problems is included, together with preliminary
results
Design project 1968: final report of Technical Survey Committee
No full textA survey has been made to determine the
factors influencing the design of a precision
turning machine with limited milling facilities.
Seventy six replies were received, have
been analysed and histograms plotted and from
an analysis of this information a technical
specification has been compiled for the machine
An investigation of the degradation of ceramic coatings on metals using a microwave technique
No full textMetal components for use in high temperature oxidising or
corrosive environments often require protection. Many of the
coatings used are complex but the two basic types are as shown
in figure 1. In type A, source material is diffused into the
surface of the component. When heated in air some of the source
material oxidises to form a thin protective ceramic layer. The
coating continues to be protective as long as there is an adequate
supply of source material to provide new ceramic to replace any
lost from the surface. Any non-destructive testing system for
such a coating must give information on the amount of source
material in reserve. In system B (figure 1) the relatively
thick ceramic coating is applied as a slurry or is sprayed on by
flame or plasma arc. The ceramic gives erosion corrosion and
thermal protection. Owing to the porosity of the ceramic
oxidation/corrosion of the protected metal will eventually take
place. This attack is the preliminary stage t- separation of the
ceramic from the metal and also to failure of the metal component.
Non-destructive testing, must give information on the interfacial
region between ceramic and metal
Extended plasticity in commercial-purity zinc sheet
No full textSome microstructures are presented, following on from CoA Memo. No.
137. Annealed c.p. zinc deforms predictably, while the as rolled metal
retains the equiaxed grain-size produced by room-temperature rolling.
Some evidence of grain growth is apparent in the material strained at
0.2 in/min
Notes on the feasibility of automatic warehousing
No full textThere is now sufficient information and experience available
on the subject of automatic warehousing to make it possible
for an organisation with major storage problems to assess
the advantages and disadvantages of investing in one of these
highly sophisticated systems provided it examines its
requirements systematically and in detail. Additionally, it
is becoming possible to compute the relative cost advantages
of this kind of storage pattern as against the conventional
one (i.e. Fork Lift Trucks and Pallet Handling).
We believe that the present position regarding the feasibility
of automatic warehousing is untenable to most organisations.
There is, so far as we know, no detailed guide available or
published which enables any organisations to make even a
preliminary examination of the possible advantages of fully
automated storage.
From the theoretical work carried out at the Materials Handling
Research Unit* we can now derive rules by which the various
factors influencing feasibility can be measured and valid
comparisons be made. The detailed application of these rules
is likely to vary from case to case, and it would be impossible
to comprehensively describe their use in a short and nontechnical
publication.
The notes which follow are not to be regarded as rigid guide lines,
but attempt to set out the criteria by which an organisation may
judge its own readiness to accept a change to mechanised storage
In-process stocks for automatic transfer lines
No full textAutomatic transfer lines are playing an increasingly important role
in production. As production rates and capital investment increase,
the cost of line stoppages also increases. A line stoppage of an
automatic transfer line occurs everytime any of the machines stops,
unless there is a sufficient buffer stock between each machine in the
line. Thus there arises the question of how much buffer stock
between each machine is required to optimise line operation in
accordance with some criterion such as maximum output or minimum
cost.
Though it is fairly easy to formulate this problem in mathematical
terms, it has been shown (Ref.1) that an analytical solution is
not possible. The problem can, however, be solved for each
particular case by simulation.
This report describes one such solution for the case of an automatic
bottling plant in a brewery. The work was carried out as a thesis
project for the college's diploma, by Mr. A.C. Roberts, a student in
the Statistics and Operational Research section, School of Management,
during the Academic year 1967/68. Mr. E. Kay of the Materials
Handling Research Unit acted as project supervisor.
As a bottling line is a prime example of an automatic transfer line,
we believe that the method here described can be applied to all
similar problems
Automatic assembly design project 1968/9 :|breport of economic planning committee
No full textInvestigations into automatic assembly systems have
been carried out. The conclusions show the major
features to be considered by a company operating
the machine to assemble the contact block with regard
to machine output and financial aspects.
The machine system has been shown to be economically
viable for use under suitable conditions, but the
contact block is considered to be unsuitable for
automatic assembly.
Data for machine specification, reliability and
maintenance has been provided
Some preliminary suggestions on the standardisation of data collection procedures from U.K. commercial hovercraft operators and an initial study into the derivation of a standard method for estimating the operating costs of hovercraft
No full textINTRODUCTION
This report is a summary of the ground covered
during a 6 month pilot study encompassing a number of aspects
of hovercraft operations. It is hoped that the experience
gained. during this period of study will enable more specific
tasks involving much more detailed analysis of particular
aspects of operations to be carried out. a) the nature of data available on past operations;
b) expected future data;
c) topics expected to yield the greatest benefits
to all parties concerned (i.e. Cranfiela, Mintech.,
the Operators and the Manufacturers, present and
prospective) both in the short and long term:
and a) manpower available.
Unfortunately the latter restriction proved more
severe than had been initially envisaged.
Fields of study considered were as follows:
(i) A study of the Problems involved in the
derivation of a Standard Method for Estimating
the Operating Costs of Hovercraft.
(ii) An attempt to Standardise the data collection
proceedures from the various current U.K. Operators.
iii) An analysis of all currently available data.
iv) An investigation into the possible use of
Automatic Data Processing techniques for the
collection and analysis of operating data.
(v) An analysis of the causes and effects of delays
and cancellations in current scheduled operations.
(vi) A study of the traffic carried on and the demand
for current scheduled services, and the effect of
varying fare structures on this
An experimental investigation into some of the problems associated with stress diffusion in the vicinity of chord-wise cut-outs in the wing, and a comparison with existing theories
No full textChord-wise openings in the skin between the spars of the wing are designed in some aircraft for undercarriage doors, bomb bay doors, and the wing fold joints of naval Aircraft. Stress concentrations exist in the region of these cut-outs where the load is transferred from the stringers and skin into the concentrated load carrying members. Two theories have evolved
to predict the resulting behaviour of the structure. The stringer sheet' theory predicts an infinite shear stress in the corners of the sheet; the 'finite stringer' theory predicts a high, finite shear stress in the corners, the magnitude of which increases with the number of stringers