Chain-store pricing and the structure of retail markets

This paper investigates competition between chain-stores and independents in the UK opticians' industry, using the relationship between the number of outlets present in a local market and the market size. Chain-stores are shown to have a significant effect on local market competition. In addition, the empirical approach is extended to allow inferences on the nature and extent of product differentiation. The results are broadly consistent with a model of vertical product differentiation in which chain-stores adopt national pricing strategies. The evidence suggests that the nature of competition between independent retailers depends on whether a chain-store is present.

Mechanisms of transfer film formation on data recording heads

The increasing demand for high capacity data storage requires decreasing the head-to-tape gap and reducing the track width. A problem very often encountered is the development of adhesive debris on the heads at low humidity and high temperatures that can lead to an increase of space between the head and media, and thus a decrease in the playback signal. The influence of stains on the playback signal of reading heads is studied using RAW (Read After Write) tests and their influence on the wear of the heads by using indentation technique. The playback signal has been found to vary and the errors to increase as stains form a patchy pattern and grow in size to form a continuous layer. The indentation technique shows that stains reduce the wear rate of the heads. In addition, the wear tends to be more pronounced at the leading edge of the head compared to the trailing one. Chemical analysis of the stains using ferrite samples in conjunction with MP (metal particulate) tapes shows that stains contain iron particles and polymeric binder transferred from the MP tape. The chemical anchors in the binder used to grip the iron particles now react with the ferrite surface to create strong chemical bonds. At high humidity, a thin layer of iron oxyhydroxide forms on the surface of the ferrite. This soft material increases the wear rate and so reduces the amount of stain present on the heads. The stability of the binder under high humidity and under high temperature as well as the chemical reactions that might occur on the ferrite poles of the heads influences the dynamic behaviour of stains. A model of stain formation taking into account the channels of binder degradation and evolution upon different environmental conditions is proposed.

Mechanisms of heat and mass transfer to and from single drops freely-suspended in an air stream

A specially-designed vertical wind tunnel was used to freely suspend individual liquid drops of 5 mm initial diameter to investigate drop dynamics, terminal velocity and heat and mass transfer rates. Droplets of distilled, de-ionised water, n-propanol, iso-butanol, monoethanolamine and heptane were studied over a temperature range of 50oC to 82oC. The effects of substances that may provide drop surface rigidity (e.g. surface active agents, binders and polymers) on mass transfer rates were investigated by doping distilled de-ionised water drops with sodium di-octyl sulfo-succinate surfactant. Mass transfer rates decreased with reduced drop oscillation as a result of surfactant addition, confirming the importance of droplet surface instability. Rigid naphthalene spheres and drops which formed a skin were also studied; the results confirmed the reduced transfer rates in the absence of drop fluidity. Following consideration of fundamental drop dynamics in air and experimental results from this study, a novel dimensionless group, the Oteng-Attakora, (OT), number was included in the mass transfer equation to account for droplet surface behaviour and for prediction of heat and mass transfer rates from single drops which exhibit surface instability at Re>=500. The OT number and the modified mass transfer equation are respectively: OT=(ava2/d).de1.5(d/) Sh = 2 + 0.02OT0.15Re0.88Sc0.33 Under all conditions drop terminal velocity increased linearly with the square root of drop diameter and the drag coefficient was 1. The data were correlated with a modified equation by Finlay as follows: CD=0.237.((Re/P0.13)1.55(1/We.P0.13) The relevance of the new model to practical evaporative spray processes is discussed.

Studies in clay chemistry

A study of clay chemistry has been approached with three aims: - to modify the conducting properties by intercalation of tetrathiafulvalene, - to study the electrochemistry of redox-active coordination compounds immobilised on clay coated electrodes, and - to study the role of clays as reagents in inorganic glass forming reactions using mainly solid-state magic-angle-spinning NMR. TTF was intercalated by smectites containing different interlayer and lattice cations. Evidence from ESR and 57Fe Mossbauer indicated charge-transfer from TTF to structural iron in natural montmorillonite, and to interlayer Cu2+ in Cu2+ exchanged laponite. No charge transfer was observed for laponite (Na+ form) itself. Ion exchange of TTF3(BF4)2 with laponite was found to proceed quantitatively. The intercalated species were believed to be (TTF)2+ dimers. Conductivity data showed an order of magnitude increase for the intercalated clays. The mechanism is thought to be ionic rather than CT as Na+ laponite showed a similar enhancement in conductivity. Mechanically robust colloidal clay films were prepared on platinum electrodes. After immersion in solutions containing redox active complexes [Co(bpy)3]3+ and [Cr(bpy)3]3+, the films became electroactive when a potential was applied. Cyclic voltammograms obtained for both complexes were found to be of the diffusion controlled type. For [Co(bpy)3]3+ immobilised on clay coated electrodes, a one-step oxidation and four-step reduction wave was observed corresponding to a one electron stepwise reversible reduction of Co(III), through Co(II), Co(I), Co(O) to Co(I) oxidation state. For [Cr(bpy)3]3+ the electrochemistry was complicated by the presence of additional waves corresponding to the dissociation of [Cr(bpy)3]3+ into the diaquo complex. ESR and diffuse reflectance data supported such a mechanism. 29Si, 27Al and 23Na MAS NMR spectroscopy, supported by powder XRD and FTIR, was used to probe the role of clays as reagents in glass forming reactions. 29Si MAS NMR was found to be a very sensitive technique for identifying the presence and relative abundance of crystalline and non-crystalline phases. In thermal reactions of laponite formation of new mineral phases such as forsterite, akermanite, sillimanite and diopside were detected. The relative abundance of each phase was dependent on thermal history, chemical nature and concentration of the modifier oxide present. In continuing work, the effect of selected oxides on the glass forming reactions of a model feldspar composition was investigated using solid state NMR alone. Addition of network modifying oxides generally produced less negative 29Si chemical shifts and larger linewidths corresponding to a wider distribution of Si-O-Si bond angles and lengths, and a dominant aluminosilicate phase with a less polymerised structure than the starting material. 29Si linewidths and 27Al chemical shifts were respectively correlated with cationic potential and Lewis acidity of the oxide cations. Anomalous Al(4) chemical shifts were thought to be due to precipitation of aluminate phases rather than a breakdown in Lowenstein's aluminium avoidance principle.

Studies of the cationic polymerisation of vinylic and energetic cyclic ether monomers

The cationic polymerisation of various monomers, including cyclic ethers bearing energetic nitrate ester (-ON02) groups, substituted styrenes and isobutylene has been investigated. The main reaction studied has been the ring-opening polymerisation of 3- (nitratomethyl)-3-methyl oxetane (NIMMO) using the alcohol/BF3.0Et2 binary initiator system. A series of di-, tri- and tetrafunctional telechelic polymers has been synthesised. In order to optimise the system, achieve controlled molecular weight polymers and understand the mechanism of polymerisation the effects of certain parameters on the molecular weight distribution, as determined by Size Exclusion Chromatography, have been examined. This shows the molecular weight achieved depends on a combination of factors including -OH concentration, addition rate of monomer and, most importantly, temperature. A lower temperature and OH concentration tends to produce higher molecular weight, whereas, slower addition rates of monomer, either have no significant effect or produce a lower molecular weight polymer. These factors were used to increase the formation of a cyclic oligomer, by a side reaction, and suggest, that the polymerisation of NIMMO is complicated with endbiting and back biting reactions, along with other transfer/termination processes. These observations appear to fit the model of an active-chain end mechanism. Another cyclic monomer, glycidyl nitrate (GLYN), has been polymerised by the activated monomer mechanism. Various other monomers have been used to end-cap the polymer chains to produce hydroxy ends which are expected to form more stable urethane links, than the glycidyl nitrate ends, when cured with isocyanates. A novel monomer, butadiene oxide dinitrate (BODN), has been prepared and its homopolymerisation and copolymerisation with GL YN studied. In concurrent work the carbocationic polymerisations of isobutylene or substituted styrenes have been studied. Materials with narrow molecular weight distributions have been prepared using the diphenyl phosphate/BCl3 initiator. These systems and monomers are expected to be used in the synthesis of thermoplastic elastomers.

Studies on DNA methylation and mechanisms of hypomethylation

The methylation of cytosinc residues in DNA is thought to play an important role in the regulation of gene expression, with active genes generally being hypomethylated. With this in mind peptides were synthcsised to mimic the cytosine-5 methylation activity carried out by DNA mcthylase, which however, showed no ability to carry out this function. The imidazotetrazinoncs are a novel group of antitumour agents which have demonstrated good activity against a range of murinc tumours and human tumour xenografts, and hypomethylation of DNA has been implicated in the mechanism of action. Studies have been conducted on the mechanism by which such agents cause hypomethylation, using DNA methylase partially purified from murine L1210 leukaemia cells. Unmodified calf thymus DNA does not inhibit the transfer of methyl groups from SAM to M.lysodeikticus DNA by partially purified DNA methylase. However, if the calf thymus DNA is modified by alkylating agents such as imida-zotetrazinones or nitrosoureas, the treated DNA becomes an inhibitor of the methylation reaction. This has been correlated with the induction of DNA damage, such as single strand breaks, since X-ray treated DNA and deoxyribonuclease treatment produces a similar effect. The mechanism of inhibition by the drug treated or damaged DNA is thought to occur by binding of the enzyme to an increased concentration of non-substrate DNA, presumably by the occurrence of single strand breaks, since neither sonication nor treatment with the restriction enzyme Mspl caused an inhibition. Attempts were made to elucidate the strict structure activity relationship for antitumour activity observed amongst the imidazotctrazinones. The transfection of a murine colon adcnocarcinoma cell line (MAC 13) with DNA extracted from GM892 or Raji cells previously treated with either the methyl (temozolomide) or ethyl (ethazolastone) imidazotetrazinone was performed. X-irradiated DNA did not cause any suppression of cell growth, suggesting that it was not due to physical damage. Transfection of MAC 13 cells with DNA extracted from GM892 cells, was more effective at inhibiting growth than DNA from Raji cells. Temozolomide treated cellular DNA was a more potent growth inhibitor than that from ethazolastone treated cells. For both agents the growth inhibitory effect was most marked with DNA extracted 6h after drug addition, and after 24h no growth suppression was observed. This suggested that the growth inhibitory effect is due to a repairable lesion. .The methylation of M.lysodeikticus DNA by DNA methylase is inhibited potently and specifically by both hereto and homoribo and dcoxyri-bopolynucleotides containing guanine residues. The inhibitory effect is unaffected by chain length or sugar residue, but is abolished when the O-6 residue of guanine is substituted as in poly d(OGG)2o. Potent inhibition is also shown by polyinosinic and polyxanthylic acids but not by polyadenylic acid or by heteropolymers containing adcnine and thymine. These results suggest that the 6 position of the purine nucleus is important in binding of the DNA methylase to particular regions of the DNA and that the hydrogen bonding properties of this group are important in enzyme recognition. This was confirmed using synthetic oligonucleotides as substrates for DNA methylase. Enzymatic methylation of cytosine is completely suppressed, when O6 methylguanine replaces guanine in CG sites.

Spatial contrast sensitivity and external noise: applications to optical and neural modulation transfer functions

The thesis will show how to equalise the effect of quantal noise across spatial frequencies by keeping the retinal flux (If-2) constant. In addition, quantal noise is used to study the effect of grating area and spatial frequency on contrast sensitivity resulting in the extension of the new contrast detection model describing the human contrast detection system as a simple image processor. According to the model the human contrast detection system comprises low-pass filtering due to ocular optics, addition of light dependent noise at the event of quantal absorption, high-pass filtering due to the neural visual pathways, addition of internal neural noise, after which detection takes place by a local matched filter, whose sampling efficiency decreases as grating area is increased. Furthermore, this work will demonstrate how to extract both the optical and neural modulation transfer functions of the human eye. The neural transfer function is found to be proportional to spatial frequency up to the local cut-off frequency at eccentricities of 0 - 37 deg across the visual field. The optical transfer function of the human eye is proposed to be more affected by the Stiles-Crawford -effect than generally assumed in the literature. Similarly, this work questions the prevailing ideas about the factors limiting peripheral vision by showing that peripheral optical acts as a low-pass filter in normal viewing conditions, and therefore the effect of peripheral optics is worse than generally assumed.

Mass transfer in fluidized bed drying of moist particulate

Bubbling fluidized bed technology is one of the most effective mean for interaction between solid and gas flow, mainly due to its good mixing and high heat and mass transfer rate. It has been widely used at a commercial scale for drying of grains such as in pharmaceutical, fertilizers and food industries. When applied to drying of non-pours moist solid particles, the water is drawn-off driven by the difference in water concentration between the solid phase and the fluidizing gas. In most cases, the fluidizing gas or drying agent is air. Despite of the simplicity of its operation, the design of a bubbling fluidized bed dryer requires an understanding of the combined complexity in hydrodynamics and the mass transfer mechanism. On the other hand, reliable mass transfer coefficient equations are also required to satisfy the growing interest in mathematical modelling and simulation, for accurate prediction of the process kinetics. This chapter presents an overview of the various mechanisms contributing to particulate drying in a bubbling fluidized bed and the mass transfer coefficient corresponding to each mechanism. In addition, a case study on measuring the overall mass transfer coefficient is discussed. These measurements are then used for the validation of mass transfer coefficient correlations and for assessing the various assumptions used in developing these correlations.

Implementing collaborative practices in the healthcare supply chain:insights into hospital-vendor operations

The paper discusses the characteristics of healthcare supply chains, and puts particular emphasis on the implementation of VMI/CMI in this sector specific context. By the means of case study research the paper provides empirical data on the benefits of the above collaborative practices for both the hospital and vendors. The paper contributes to the stream of research on VMI/CMI in the healthcare sector, where limited research attempts have been conducted so far. In contrast to other surveys this case study shows that specific and measurable cost reductions exist, in addition to other improvements such as better control over the inventories, and also in reduction of administrative work. Results obtained may be also relevant to other hospitals and vendors and as they can form a basis for comparisons. Copyright © 2013 Inderscience Enterprises Ltd.

Theoretical perspectives in purchasing and supply chain management:an analysis of the literature

Purpose – This paper attempts to seek answers to four questions. Two of these questions have been borrowed (but adapted) from the work of Defee et al.: RQ1. To what extent is theory used in purchasing and supply chain management (P&SCM) research? RQ2. What are the prevalent theories to be found in P&SCM research? Following on from these questions an additional question is posed: RQ3. Are theory-based papers more highly cited than papers with no theoretical foundation? Finally, drawing on the work of Harland et al., the authors have added a fourth question: RQ4. To what extent does P&SCM meet the tests of coherence, breadth and depth, and quality necessary to make it a scientific discipline? Design/methodology/approach – A systematic literature review was conducted in accordance with the model outlined by Tranfield et al. for three journals within the field of “purchasing and supply chain management”. In total 1,113 articles were reviewed. In addition a citation analysis was completed covering 806 articles in total. Findings – The headline features from the results suggest that nearly a decade-and-a-half on from its development, the field still lacks coherence. There is the absence of theory in much of the work and although theory-based articles achieved on average a higher number of citations than non-theoretical papers, there is no obvious contender as an emergent paradigm for the discipline. Furthermore, it is evident that P&SCM does not meet Fabian's test necessary to make it a scientific discipline and is still some way from being a normal science. Research limitations/implications – This study would have benefited from the analysis of further journals, however the analysis of 1,113 articles from three leading journals in the field of P&SCM was deemed sufficient in scope. In addition, a further significant line of enquiry to follow is the rigour vs relevance debate. Practical implications – This article is of interest to both an academic and practitioner audience as it highlights the use theories in P&SCM. Furthermore, this article raises a number of important questions. Should research in this area draw more heavily on theory and if so which theories are appropriate? Social implications – The broader social implications relate to the discussion of how a scientific discipline develops and builds on the work of Fabian and Amundson. Originality/value – The data set for this study is significant and builds on a number of previous literature reviews. This review is both greater in scope than previous reviews and is broader in its subject focus. In addition, the citation analysis (not previously conducted in any of the reviews) and statistical test highlights that theory-based articles are more highly cited than non-theoretically based papers. This could indicate that researchers are attempting to build on one another's work.

Technology transfer and sustainable industrial development for developing countries

This paper reports on a part of work for the UNIDO initiative on technology transfer for sustainable industrial development. The proposed technology transfer framework, adapted from the East Asian late industrialisers model, identifies two categories of countries requiring support for enhancing their technological capabilities: (a) very late industrialisers (“low income” developing countries), and (b) slow industrialisers (countries with sizeable manufacturing sectors but limited success in gaining international competitiveness) and three technology transfer routes: (a) through trade and aid to strengthen indigenous production for domestic markets (Route 1); (b) through FDI and contracting to develop export oriented firms (Route 2), and (c) through the supply chain of capital equipment and materials to develop local subcontracting capacity (Route 3). Very late industrialisers need support to start with Route 1 in selected sectors and upgrade through imported mature technologies. Appropriate product innovations are also possible. The slow industrialisers have more scope for increased technology transfer through Routes 2 and 3.

Technology transfer and competitive operations:the valuation and collaboration questions

To improve competitiveness and find new markets companies are extending their operations through collaborations involving technology transfer. However, such collaborations have often been based on ad hoc agreements resulting from negotiations in which each side has been inadequately equipped with information about the other’s motivations and expectations. As a result there has been a gap in the ‘value’ attached to the technology, leading to delays or even failure in reaching an agreement. To address this problem a technology valuation and collaboration model has been developed using empirical data gathered from various points along the UK-China value chain for machine tool technology.

Transfer of patients from health care centres to special care services:analysis of travel distances in Nordic countries

Objectives: This paper highlights the importance of analysing patient transportation in Nordic circumpolar areas. The research questions we asked are as follows: How many Finnish patients have been transferred to special care intra-country and inter-country in 2009? Does it make any difference to health care policymakers if patients are transferred inter-country? Study design: We analysed the differences in distances from health care centres to special care services within Finland, Sweden and Norway and considered the health care policy implica tions. Methods: An analysis of the time required to drive between service providers using the "Google distance meter" (http://maps.google.com/); conducting interviews with key Finnish stakeholders; and undertaking a quantitative analyses of referral data from the Lapland Hospital District. Results: Finnish patients are generally not transferred for health care services across national borders even if the distances are shorter. Conclusion: Finnish patients have limited access to health care services in circumpolar are as across the Nordic countries for 2 reasons. First, health professionals in Norway and Sweden do not speak Finnish, which presents a language problem. Second, The Social Insurance Institution of Finland does not cover the expenditures of travel or the costs of medicine. In addition, it seems that in circumpolar areas the density of Finnish service providers is greater than Swedish ones, causing many Swedish citizens to transfer to Finnish health care providers every year. However, future research is needed to determine the precise reasons for this.

Mass transfer and chemical reaction on a distillation plate

A multistage distillation column in which mass transfer and a reversible chemical reaction occurred simultaneously, has been investigated to formulate a technique by which this process can be analysed or predicted. A transesterification reaction between ethyl alcohol and butyl acetate, catalysed by concentrated sulphuric acid, was selected for the investigation and all the components were analysed on a gas liquid chromatograph. The transesterification reaction kinetics have been studied in a batch reactor for catalyst concentrations of 0.1 - 1.0 weight percent and temperatures between 21.4 and 85.0 °C. The reaction was found to be second order and dependent on the catalyst concentration at a given temperature. The vapour liquid equilibrium data for six binary, four ternary and one quaternary systems are measured at atmospheric pressure using a modified Cathala dynamic equilibrium still. The systems with the exception of ethyl alcohol - butyl alcohol mixtures, were found to be non-ideal. Multicomponent vapour liquid equilibrium compositions were predicted by a computer programme which utilised the Van Laar constants obtained from the binary data sets. Good agreement was obtained between the predicted and experimental quaternary equilibrium vapour compositions. Continuous transesterification experiments were carried out in a six stage sieve plate distillation column. The column was 3" in internal diameter and of unit construction in glass. The plates were 8" apart and had a free area of 7.7%. Both the liquid and vapour streams were analysed. The component conversion was dependent on the boilup rate and the reflux ratio. Because of the presence of the reaction, the concentration of one of the lighter components increased below the feed plate. In the same region a highly developed foam was formed due to the presence of the catalyst. The experimental results were analysed by the solution of a series of simultaneous enthalpy and mass equations. Good agreement was obtained between the experimental and calculated results.

The need for wider supply chain management adoption:empirical results from Ireland

Purpose - This paper aims to provide empirical results which suggest that there is a need for more widespread adoption of supply chain management among Irish firms. Design/methodology/approach - The Republic of Ireland is a small, open, trade-dependent economy and is one of the fastest growing economies in the developed world. However, due to rising costs, there is an increasing trend in Ireland to outsource lower function manufacturing processes to lower-cost locations but to retain high-skill functions (such as R&D). This trend, together with other factors such as its peripheral location, suggests that supply chain management is critical from an Irish perspective. In order to gain unique insights of current levels of awareness/adoption of SCM and the potential impact SCM could have on competitiveness, a survey was conducted among 776 Irish firms. Findings - Overall, the findings suggest that many firms in Ireland pay lip-service to the importance of SCM elements and objectives but the majority of firms, about two thirds, have only a passing understanding of what constitutes SCM. Only 25 per cent adopt SCM programmes and only 9 per cent of Irish companies have a specialised SCM or logistics manager. The gaps in their understanding of SCM are matched by the gaps in their awareness of key costs (e.g. 59 per cent of companies do not know their total supply chain costs). While there are supply chain management adopters in Ireland that are already well up the s-curve of innovation transfer, it is the larger group of less aware companies that must become better at how they manage their supply chains. Originality/value - The paper offers a useful insight into supply chain management and its role in Irish industry. © Emerald Group Publishing Limited.