Forum 2 Abstracts November 2003
Link to Meeting Programme and on to
Registration form
List of Forum II presentations in chronological order with
links to abstracts
By author Thursday: Harrison
– Evans – Buckton – Cooper
– Barnes – Threlfall – Rogers
– Parsons – Shaw – Frampton –
Sankar – Grant
– Melzer – Roberts – Norval
– Cressey.
By author Friday: Small – Watt – Holdway
– Royall – Farnworth – Barker
– Beveridge – Mackay – Shackleton –
Korsunsky.
Thursday 13th November 2003
- 11:00 Abstract In Situ Diffraction
from Materials and Macromolecules under Microwave Irradiation.
– Andrew Harrison, University of Edinburgh
- 11.30 Abstract Non-ambient Laboratory
Powder Diffraction Studies - Synthesis, Kinetics and Phase
Transitions – John Evans, University of Durham
- 12.00 Abstract A review of methods use to
quantify amorphous content in "crystals" – Graham
Buckton,The School of Pharmacy, University of London.
- 14:00 Abstract Relative Humidity Controlled X-ray Powder Diffraction –
Brett Cooper, Merck Sharpe & Dohme
- 14:00 Abstract Use of Intense Radiation
Sources in the study of Functional Materials – Paul
Barnes, Birkbeck College
- 14:25 AbstractBeyond Isostructurality – Structural Similarity,
Dissimilarity and Representation. – Terry
Threlfall, University of Southampton
- 14:25 Abstract Standardless phase
quantification of industrial coatings – Keith Rogers,
RMCS Cranfield University
- 14:50 Abstract Polymorphism Induced by
High Pressure – Simon Parsons, School of Chemistry, The
University of Edinburgh
- 14:50 Abstract Understanding Gear Performance
with X-ray Diffraction – Brian Shaw, University of
Newcastle
- 15:45 Abstract Polymorphic Drugs Science,
Fashion or Valuable Products – Chris Frampton,
Bruker Nonius B.V.
- 15:45 Abstract Building your own furnace for
HT-XRD – Gopinathan Sankar, Royal Institution
- 16:10 Abstract Polymorphism Studies in
the Pharmaceutical Industry: The importance of medium and low
throughput characterisation in a high throughput world –
Craig Grant or Dan Cowell, Pharmorphix Limited
- 16:10 Abstract Using High temperature X-ray
diffraction within steel/aluminum production: look where the
action is! – Stefan Melzer, Corus the
Netherlands
- 16:35 Abstract Thermal Transformations - case studies –
Ron Roberts, AstraZeneca
- 16:35 Abstract Inconstant Catalysts
– Steve Norval, ICI Measurement Science Group
- 17:45 Abstract Introduction to Ron
Jenkins Memorial Lecture – Dave Taylor, ICDD
- 18:00 Abstract Ron Jenkins Memorial
Lecture: New developments in powder diffraction at the
Natural History Museum: applications using fast detectors and
high– brightness sources – Gordon Cressey, Natural
History Museum
Friday 14th November 2003
- 9.30 Abstract Industrial Group Award
Lecture: Adventures in Crystallography in the Gas Turbine
Industry.– Colin Small, Rolls-Royce plc
- 11:00 Abstract Structural characteristics of the
amorphous phase: A computer modelling approach.– Stephen
Watt, Pfizer.
- 11:00 Abstract Microstructural Characterisation of
Advanced Materials Using Electron BackScattered Diffraction. – Phil Holdway, QinetiQ
- 11:30 Abstract Application of Dynamic
Mechanical Analysis in the Characterisation of Amorphous Powders
– Paul Royall, Kings College London
- 11:30 Abstract XRD and Reflectivity
Measurements in the Glass Industry. – Mark Farnworth,
Pilkington plc.
- 12:00 Abstract The use of Thermally
Stimulated Current Spectroscopy in the study of amorphous and
polymorphic materials – Susan Barker, University of East
Anglia
- 12:00 Abstract Applications of XRD
in the Imaging Industry. – David Beveridge, Ilford
Ltd
- 14.00 Abstract Past –
"Who controls the past controls the future" – Professor Alan L. Mackay, FRS. Birkbeck College.
- 14.30 Abstract Present –
"It's a Diffractometer Captain but Not as We Know It" –
Judith Shackleton, Manchester Materials Science Centre.
- 15.00 Abstract Future – Alun Bowen
Lecture,– "Structural Engineering Studies Using High Energy X-Ray Diffraction"–
Alexander Korsunsky, Oxford University,
Dept. of Engineering Science
ABSTRACTS
- 1. In Situ
Diffraction from Materials and Macromolecules under Microwave
Irradiation. – Andrew Harrison, University of
Edinburgh
-
Microwave heating is becoming increasingly important as a method
of driving chemical synthesis and materials processes, both in
solution, and in the solid state. There are several ways in which
this method of heating a sample may be different from more
conventional techniques: regions of the sample with higher
dielectric constant are heated more rapidly and to higher
temperatures; the electric field may be particularly efficient at
activating motion of ions or polar species in solution, or in the
solid state. However, the field has suffered from a lack of
direct experimental measurements of the nature – and hence
the potential for application – of such effects. We have
developed several different types of microwave reactor that
enable us to perform X-ray or neutron scattering measurements on
powders, single crystals or particles suspended in solution
during microwave irradiation, and to measure temperature
accurately and precisely. I will describe the principles of
designing and operating such equipment, and describe some of our
work on phase transformations in microwave dielectric materials,
and the potential to use such methods to probe the possible
effect microwave radiation may have on the structure of proteins
and biological membranes.
- 2. Non-ambient
Laboratory Powder Diffraction Studies - Synthesis, Kinetics and
Phase Transitions – John Evans, University of
Durham
-
In this presentation I will try and show some of the experiments
that are now possible using laboratory based non-ambient powder
diffraction methods. I will briefly review attachments that are
commercially available for both low and high temperature studies
on lab instruments. I'll then discuss how time and temperature
resolved experiments can yield significant crystallographic and
non-crystallographic information about a material's properties
and reactivity. Examples will include using in-situ studies to
follow unusual thermal contraction of materials; to follow
structural phase transitions; to probe the kinetics and
activation energies of atomic motion in the solid state; to
optimise chemical synthesis; and to gain mechanistic insight on
solid-state processes. The methodologies presented will hopefully
be of relevance to a range of problems in materials,
pharmaceutical and solid-state chemistry.
- 3. A review of
methods use to quantify amorphous content in "crystals"
– Graham Buckton, The School of Pharmacy, University of
London.
-
A common cause of batch to batch variability is the presence of small
quantities of processing induced disorder in essentially crystalline powders.
Often an amorphous content of just a few % of the total sample mass can
cause significant changes in the performance during processing and use of
the material. Many methods now exist to study low levels of amorphous content.
In this lecture some of these methods will be reviewed, namely gravimetric
sorption, near IR spectroscopy, inverse gas chromatography and hyper-DSC.
The highlights and limitations of these techniques will be described.
- 4. Relative Humidity Controlled
X-ray Powder Diffraction – Brett Cooper, Merck Sharpe &
Dohme
-
Relative Humidity Controlled X-ray Powder Diffraction
Understanding and monitoring the effect of relative humidity on active
pharmaceutical ingredients and excipients is an important aspect of developing
a pharmaceutical dosage form. This presentation will give an overview of the
use of relative humidity (RH) controlled XRPD. A brief description of what
relative humidity is and how water content and RH vary with temperature will
be given. There will be an introduction to the complementary technique -
Dynamic Vapour Sorption. The presentation will then go on to describe the
two main methods for running RH controlled XRPD experiments: manual RH control
and automated temperature and RH control. Finally some examples and results
will be presented to demonstrate the application of RH controlled experiments.
- 5. Use of
Intense Radiation Sources in the study of Functional
Materials – Paul Barnes, Industrial Materials
Group, Department of Crystallography, Birkbeck College, Malet
Street, London WC1E 7HX, U.K.
-
Neutron and synchrotron sources are transforming the style and
type of science practised in both academic and industrial
research institutes. In addition to providing new techniques,
these sources enhance traditional methods such as diffraction: in
particular rapid time-resolved diffraction and in situ
diffraction permit the observation of functional materials under
real working conditions. Penetrating radiation and
space-resolution are two further important attributes
which can be used to expose, to examination, the
structural/chemical gradients occurring inside bulk material
systems. These features will be illustrated with results obtained
using energy-dispersive and angle-dispersive detectors; examples
will be selected from:
- structural (framework) transformations during
dehydration;
- the birth of a zeolite membrane;
- crystallisation gradients in chemical engineering
systems;
- diffusion of chemical species/pathogens into the environment
or storage media;
- pharmaceutical and macro-molecular systems.
- 6. Beyond Isostructurality - Structural Similarity,
Dissimilarity and Representation. Terry Threlfall – University of Southampton
-
Unit cells are probably the
least helpful representation of isostructurality. We have been seeking
more useful representations. Application of these to Tartrates, Frusemide
and to the structural systematics of Sulphonamides has revealed unexpected
relationships between structures.
- 7. Standardless
phase quantification of industrial coatings – Keith
Rogers, RMCS Cranfield University
-
K.D. Rogers1 S.E. Etok1 R.
Scott2
1Centre for Materials Science & Engineering,
Cranfield University, Swindon, U.K.
2Biomet-Merck, Swindon, Wiltshire, U.K.
Plasma spraying is a common commercial process for fabricating
coatings on metallic substrates. However it has several
disadvantages including high start-up costs, high energy costs,
inefficient use of stock material and line-of-sight only coating.
In particular for the medical devices industry where calcium
phosphates are coated onto hip stems, this fabrication route does
not allow incorporation of biologically active molecules. As an
alternative to plasma spraying, we have been studying low
temperature, direct electrodeposition of hydroxyapatite on
titanium substrates.
The characterization of these coatings is problematic. In
particular the amount of amorphous material present is difficult
to determine as the coating cannot be removed from the substrate
and conventional spiking methods cannot be used. Further, for the
thinner electrodeposited samples, substrate peaks are the
dominant component of the diffraction pattern.
We present a standardless method of phase quantification that
includes the amorphous material. This is based upon a Rietveld
approach to quantify the phases present, and has been verified
through determination of known mixtures. The method
simultaneously provides accurate lattice parameters and may
accommodate preferred orientation.
- 8. Polymorphism
Induced by High Pressure –Simon Parsons, School of
Chemistry, The University of Edinburgh
-
High pressure (> 1 kbar) crystallography is a mature
discipline in physical and geological applications. It has been
widely applied to the study of metals, minerals and very small
molecules of interest in planetary science (CH4,
H2O and NH3). High pressure studies of
molecular systems are relatively much less common. However, high
pressure is a potentially very powerful tool in polymorph
research because it directly influences intermolecular bond
lengths. This talk will begin with a brief discussion of
experimental procedures, particularly data collection using CCD
diffractometers. New polymorphs have been obtained at modest
pressures (1 - 15 kbar) for a variety of simple organic systems
including formamide, pyridine, N-methylmethanesulfonamide and
glycine. High pressure has also been observed to stabilise
co-crystals which do not form under ambient conditions (e.g.
paracetamol.MeOH and piperidine.0.5H2O).
- 9. Understanding
Gear Performance with X-ray Diffraction – Brian
Shaw, Design Unit, University of Newcastle
-
The failure of hardened, high performance gearing normally occurs through a
process of fatigue and is usually attributed to a combination of the material
properties along with gear design and mechanical alignment. Improvements in
the fatigue strength of gears is therefore of great importance in attaining
increased load carrying capacities and in improving component reliability.
Neglecting gear design and alignment, which both alter the stressing on the gear,
the material properties are the most important factor that can be modified to
improve fatigue performance. This paper will illustrate how X-ray diffraction
has been used to better understand material properties to assist gear research
and development programmes and to understand in-service failures. The examples
will show how an understanding of residual stress levels gained from X-ray
diffraction have resulted in an appreciation of the importance of accurate
quality control of heat treatment, subsequent grinding and post heat treatment
blasting processes in order to maximise component reliability and performance.
- 10.
Polymorphic Drugs Science, Fashion or Valuable Products
– Chris Frampton, Bruker Nonius B.V., Oostsingel 209, 2612 HL Delft,
The Netherlands. chris.frampton@bruker-nonius.com
-
The intellectual property that is associated with a pharmaceutical product
is not limited purely to the 2D-chemical structure of the active pharmaceutical
ingredient (API) but can also be extended to cover its polymorphic form, i.e. a
particular crystalline or solid-form of the API. The choice of polymorphic form
is often crucial to the overall performance of the drug product since new
solid-forms can have improved properties which will add value and benefit to
the drug product in many different ways.
Polymorph patenting can have serious economic consequences. On the one hand
it can extend the patent protection of a particular product and as such give a
greater return on the original R&D investment. On the other hand it can
leave the product open to attack from Generic manufacturers and as a result may
be the subject of costly global legal proceedings. This lecture will focus on
three particular case scenarios which epitomize 'the good, the bad and the ugly'
of solid-form patenting.
- 11. Building
your own furnace for HT-XRD – Gopinathan Sankar,
Davy Faraday Research Laboratory,
The Royal Institution of GB, 21 Albemarle Street,
London. W1S 4BS
-
Many solid-state complex oxide catalytic materials undergo structural
modifications during the preparation,
activation and reactions. It is important to understand the structural
features of these systems at operating conditions to determine the
structure-function relationships. In order to carry out measurements
at non-ambient temperatures, it is necessary to design and fabricate in situ
cells for specific applications. Here some of the in situ cells developed for
diffraction and combined techniques will be discussed along with few examples
of phase transformation in catalytic materials.
- 12. Polymorphism
Studies in the Pharmaceutical Industry: The importance of medium
and low throughput characterisation in a high throughput
world – Craig Grant or Dan Cowell, Pharmorphix
Limited
-
The importance of early polymorph identification and
characterisation is without doubt, highly desirable in the drug
development pipeline. Initiating these studies at an early stage
minimises problems often encountered in late stage development
and even worse clinical phases.
The widely publicised advent of high throughput experimental
methods in sample generation and faster analysis has greatly
aided this objective, e.g., automated crystallisation
linked to XRPD.
This information is most useful when coupled with data
obtained from an armoury of techniques that are best described as
low or medium throughput, e.g., stability,
solubility measurements. All this information is best collated to
compile a definitive package of data for each polymorphic
form,
Similarly a combination of techniques (including VT-XRPD) are
often applied with great effect to investigate the stability and
interconversion between forms.
Techniques and approaches to the above are presented and
illustrated with a case study.
- 13. Using High
temperature X-ray diffraction within steel/aluminum production:
look where the action is! – Stefan Melzer, Corus RD&T,
Ceramics Research Centre, The Netherlands
-
It is often difficult or even impossible to understand processes occurring at
high temperatures. Conventional experimental post-mortem techniques, where
quenched samples are investigated, often lead to inconsistent and hardly
interpretable results. However, almost all crucial processes during steel and
aluminum making run at temperatures between 300 ēC and 1600 ēC. In order to
improve and control production processes, to develop new or better materials
or to understand and prevent material failures, it is essential to follow melting
and crystallisation of materials (e.g. steel slag), phase transitions
(ferrite-austenite during hot-rolling) or reaction kinetics (aluminum sheet
during hot-rolling and annealing steps) in-situ at temperatures where they take
place. A suitable analytical tool to study such processes is High Temperature
X-ray Diffraction (HT-XRD).
- 14. Thermal Transformations -
Case studies – Ron Roberts, AstraZeneca Macclesfield
-
The use of thermal analysis, in particular Differential Scanning Calorimetry
(DSC) and Thermogravimetric Analysis (TGA) has long been a valuable tool for
understanding thermal transformations in Pharmaceutical materials. However
sometimes interpretation of the thermal events which occur during heating and
cooling are difficult to understand without recourse to other characterisation
techniques.
Examples will be used that demonstrate different thermal events and in two cases
how these events can be linked to structural changes during heating/cooling.
Other techniques that will be cited include Dynamic Vapour Sorption (DVS),
Hot-stage X-Ray Diffraction, Solid-State NMR etc.
- 15. Inconstant
Catalysts – Steve Norval, ICI Measurement Science
Group
-
Heterogeneous catalysts are crucial in making a large proportion
of the chemicals we use daily. They help to produce the fuel our
cars burn and to clean the exhaust gases. The margarine many of
us eat was oil until it was catalytically solidified. A catalyst
is usually defined as a substance that increases the rate of a
chemical reaction without itself being changed by it. Reality is
not as simple as that and the "science" of catalysts can be more
like a black art. Solid catalysts transform chemically and
physically as they are activated for use and throughout their
lifespan. Much of the relevant information about their
performance is at the level we probe by XRD - phases, crystal
structure, microstructure (nanostructure?). But there is always
the likelihood that the catalyst in the reactor is not the same
as the one put in or the one taken out. That is where in
situ XRD is vital. Some typical catalyst systems and the
techniques used to characterise them will be presented.
- 16. Introduction
to Ron Jenkins Memorial Lecture – Dave Taylor,
ICDD
-
Some views on the contribution Ron made to our science and how
he touched peoples lives.
- 17. Ron Jenkins
Memorial Lecture: New developments in powder diffraction at
the Natural History Museum: applications using fast detectors and
high– brightness sources – Gordon Cressey,
Natural History Museum
-
Since 1926 powder diffraction has played an important role in
mineralogical research at the Museum, but in recent years our
routine approach to problem-solving has been totally transformed
by using INEL 120-degree curved position-sensitive detectors. The
versatility of this style of detection is apparent from the range
of investigations that we undertake, and the speed with which we
collect full (120 degree) patterns for: routine
identification/characterization (seconds); real-time fast
transformation behaviour at elevated temperatures (seconds to
minutes); full quantitative phase analysis (minutes); detection
of trace or weakly-diffracting phases (in a few hours). With the
advent of the lab-based high-brightness focussed Microsource
(Bede Scientific), we can now also perform micro-diffraction from
small objects, in situ, with a 50-micron X-ray probe.
A variety of applications showing the efficacy of these
systems will include QPA of (normally difficult) complex mixtures
in meteorites, clays, pharmaceuticals and organic/inorganic
geomaterials, QPA of amorphous/crystalline mixtures,
time-resolved observations of fast structural re-arrangement of
hydrous interlayers in dehydrating clays, real-time thermal
expansion (and negative thermal expansion) behaviour in copper
uranyl phosphate hydrate (metatorbernite) and in magnesium
hydroxy silicate (antigorite), micro-diffraction characterization
of new Cu-Ti-nitrides found in diamond, and
dilute-micro-diffraction as applied to characterizing
experimental materials made to simulate early solar system gas
condensates and also to air-borne particulates on plastic
filters.
- 18. Industrial
Group Award Lecture: Adventures in Crystallography in
the Gas Turbine Industry.– Colin Small, Rolls-Royce
plc, P.O Box 31, Derby, DE24 8BJ, UK
-
1991. This was the first occasion I ever spoke at a BCA meeting.
The venue was Sheffield and the subject was secondary phase
extraction of developmental nickel based superalloys. The write
up in crystallography news was 'Colin Small of Rolls-Royce has
developed an electrolytic dissolution method for determination of
sigma phase in nickel based alloys for turbine discs' Accurate
but short on detail!
Since then I have had a great deal of fun analysing some of
the stranger things Roll-Royce has managed to do to its gas
turbines and the components they contain. This ranges from the
effects of ingesting deserts, de-icing salt, concrete dust and
volcanoes through terrifying engineers with titanium texture
diagrams to firing neutrons through nickel discs to determine
residual stress.
I have also had the chance to study green slime from the local
swimming pool (part of the help the community bit from RR) and
dead birds with the classic question 'Did it die of asbestosis?
(it was rotting and covered with maggots so the answer was - I
don't know and am not analysing that!!). This talk will
illustrate some of these rather odd projects and hopefully show
that XRD analysis is valuable in the most unexpected
situations.
- 19. Structural
characteristics of the amorphous phase: A computer
modelling approach.– Stephen Watt1,
(James A. Chisholm2, William Jones1,
Sam Motherwell2)
-
1Pfizer Institute for Pharmaceutical Materials Science,
Department of Chemistry, University of Cambridge, Lensfield Road,
Cambridge, CB2 1EW, UK.
2Pfizer Institute for Pharmaceutical Materials Science,
Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge, CB2 1EZ, UK.
In the broadest sense, molecular dynamics is concerned with molecular motion
over a period of time. With the advent of new supercomputers and parallel
coding, molecular dynamics simulation techniques have become useful tools in
the study of complex chemical phenomena. Fifteen years ago, a molecular dynamics
simulation involving a few thousand atoms would have been deemed too
computationally intensive to perform; however, by today's standards it can be
carried out quite easily on affordable desktop workstations. Also, with
development of more efficient programming code the timescale scale in which
these computational methods can simulate has gone from the pico second time
region to the nano second time region. Combining this with the highly accurate
parameters that are now used to describe the molecular models used in these
simulations, correlation between theory and experiment can be striking. It is
my intention in this presentation to give an account of how molecular dynamics
techniques can be used to gain a valuable insight into the properties of
amorphous carbohydrates and their aqueous solutions. In particular I will be
concentrating on how this technique can be used to accurately simulate the
glass and melting transitions exhibited by amorphous and crystalline
carbohydrate molecules, respectively. It is also intended to emphasise the
importance of using accurate parameters for simulations and the importance of
employing the correct methodology to simulate a particular event. The
presentation will conclude by mentioning a few successful applications of
molecular dynamics simulation techniques in the study amorphous carbohydrates.
- 20. Microstructural
Characterisation of Advanced Materials Using Electron BackScattered Diffraction
. – Phil Holdway and (H.S. Ubhi)
Structures and Materials Centre, QinetiQ Ltd, Cody Technology Park, Farnborough,
Hampshire
-
Electron BackScattered Diffraction (EBSD) is now an established technique for
microstructural characterisation in a wide variety of advanced metals, alloys,
ceramics and composites.
In the presentation, the basics of the technique, including aspects such as
sample preparation, will be outlined. Some recent examples of the use of EBSD
in projects undertaken at QinetiQ Ltd will be shown. This will include texture
and grain size measurements in tungsten, particle identification in alloys and
orientation relationships in Zircaloy. If time permits, some comparison with
x-ray measurements will be made.
- 21. Application
of Dynamic Mechanical Analysis in the Characterisation of
Amorphous Powders – Paul Royall, Kings College
London
-
Dynamic Mechanical Analysis, DMA, is a well-known technique for the
measurement of the mechanical properties of a sample as a function of temperature.
A typical DMA experiment involves constraining the solid, or semi-solid sample
within the instrument and subjecting it to an oscillating stress. DMA
instruments measure the force applied to the sample together with the amplitude
and phase of the resultant displacement.
DMA is a powerful technique used for the characterisation and quantification
of polymeric amorphous materials. Dynamic mechanical methods are the most
sensitive way of measuring the glass transition associated with most amorphous
materials. This is because of the large change in viscosity and thus mechanical
properties associated with the glass transition region. Consequently, the
sensitivity of DMA toward identifying the glass transition is high. However,
the application of DMA is currently restricted to self-supporting materials for
example films, bars, compacts or fibres. In terms of DMA's application within
the analytical and pharmaceutical sciences this is especially prohibitive, as
most amorphous or semi amorphous materials of therapeutic interest are commonly
powders, e.g. micronised, spray or freeze dried materials.
Thus, the aim of the present study was to investigate the ability of DMA
using a recently developed powder pocket system to detect and quantify small
amounts of amorphous material in otherwise crystalline pharmaceutical powders.
Using mixtures of amorphous and crystalline lactose, a linear relationship
between amorphous content and DMA relaxation strength was observed. This result
suggests the possibility of detecting amorphous content in the 1% or lower range.
Amorphous material was readily detected in a sample of micronised crystalline
lactose, however the DMA response for the processed sample was complex.
The initial results are encouraging but further work is required to
investigate the influence of particle size, dimension of the pocket and loading
mass on the detection and quantification limits.
- 22. XRD and
Reflectivity Measurements in the Glass Industry. –
Mark Farnworth, Pilkington plc.
XRD and X-ray Reflectivity Measurements are used for the
characterisation of thin coatings on glass and for the analysis
of glass making raw materials and refractory materials used in
the glass production processes. The presentation will give an
overview of the types of measurements carried out at Pilkington.
The methodology for determining the glassy phase, quartz,
cristobalite and tridymite contents of refractory materials will
be described. XRD and X-ray Reflectivity measurements of both
single layer and multilayer stacks on glass are routinely carried
out. The presentation will show the type of information that can
be obtained from sometimes thin, highly crystallographically
textured coating layers using the techniques of X-ray Powder
Diffraction (XRPD), Glancing Angle X-ray Diffraction(GAXRD)and
pole figure and X-ray reflectivity measurements. The use of a
Round Robin exercise to validate the results from X-ray
reflectivity will be described.
-
- 23. The use of
Thermally Stimulated Current Spectroscopy in the study of
amorphous and polymorphic materials – Susan Barker
and (Milan Antonijevic), School of Chemical Sciences and
Pharmacy, University of East Anglia, Norwich, Norfolk, NR4
7TJ.
-
This presentation will describe Thermally Stimulated Current
spectroscopy and illustrate its use in the characterisation of
pharmaceutical materials. TSC is an electrical technique whereby
dipolar movement and relaxation is measured, under the influence
of varying thermal and electrical stresses. We have studied TSC
as a means of characterising the amorphous to crystalline
transition of small molecular weight compounds, such as
indomethacin, and polymeric compounds, such as PEG. Additionally,
we have studied the polymorphic transitions of small molecular
weight compounds, such as caffeine, with TSC. TSC in the
"depolarisation" mode was successful in identifying the Tg
of indomethacin, as compared to MTDSC data and we were able to
clearly identify the Tg of low molecular weight PEGs (eg
600 and 6000), which is difficult to obtain by other means. Using
the "polarisation" and "spontaneous depolarisation" modes, in
addition to "depolarisation" mode, we have been able to show
differential responses of caffeine polymorphs I and II and are
currently relating these to molecular arrangements in the two
polymorphs. In conclusion, TSC is a useful adjunct technique in
the characterisation of amorphous and polymorphic materials.
- 24.
Applications of XRD in the Imaging Industry. –
David Beveridge, Ilford Ltd
-
Over the last half-dozen years the photographic industry has been
transformed into the imaging industry. Silver halide photography
is falling in popularity, and is being replaced by digital
imaging. Each has its own quirks, and many aspects of both can be
elucidated with the help of XRD. I shall present a wide range of
examples from both silver halide photography and digital imaging,
and show how crystallography has helped in our understanding of
the processes and problems. In our industry, we are indeed living
in interesting times!
- 25. Past
– "Who controls the past controls the future" – Professor
Alan L. Mackay, FRS. Birkbeck College.
-
Since the history of crystallography is particularly well documented, it is
of interest and indeed of use, in looking back, to see, in the light of what
we know now, who was right and who was wrong and for what reasons. In the last
50 years science has changed enormously, not always for the better. A recent
number of Zeitschrift fur Kristallographie (7/8 (2002)) collected 100 opinions
on the future. I offer some more.
- 26.
Present – Judith Shackleton, Manchester Materials
Science Centre.
-
"It's a Diffractometer Captain but Not as We Know It."
There are a vast number of different types of XRD instruments on the market
today. We are no longer confined to the old "bacon slicer". There is a dizzying
array of different optics, detectors etc. In this talk we try to make some sense
of this wilderness by exploring some of the basic configurations.
As there are so many variations we will concentrate on instruments for powder
diffraction, stress and texture.
- 27. Future
– Alun Bowen Lecture – Alexander Korsunsky,
Oxford University, Dept. of Engineering Science
-
STRUCTURAL ENGINEERING STUDIES USING HIGH ENERGY X-RAY DIFFRACTION.
Alexander M. Korsunsky, Department of Engineering Science, University of
Oxford, Parks Road, Oxford OX1 3PJ, U.K.
The availability of high flux, high energy X-ray instruments suitable
for structural engineering research at SRS, Daresbury and ESRF, Grenoble
has seen major improvements in the last decade. This led to systematic
advances in various uses of high energy X-ray beams for non-destructive
engineering analysis. Some of the recent achievements will be
illustrated that are likely to determine avenues for further
development.
The future will be strongly affected by the advent of new facilities,
notably the dedicated engineering instrument JEEP and accompanying
support facilities on DIAMOND, alongside the existing ENGIN-X neutron
scanner. Although past may be a poor indicator of the future, it is all
we have to go on in our attempts to provide the best engineering
facility for years to come. I shall try to discuss the strategy for
engineering instrumentation development in the light of industrially
motivated research driving it.
|
Industrial Group of the BCA