This thesis is divided into four main sections. In the 'Introduction' an attempt has been made to give, by a historical approach, a brief account of some of the advances which have been made towards a solution of the general problem of evaluating the energy associated with chemical bonds in the undisturbed molecule and also that required to disrupt the molecule into two fragments. A detailed review of the many experimental methods available for the determination of bond dissociation energies has not been given since there are now good accounts available in the literature, but attention has been focused on those techniques which are of interest in connection with the present investigation. The 'Present Investigation' deals with all the experimental work which has been carried out in the examination of diphenyl-methane, fluorene, diphenyl ethyl bromide, tetraphenylethane and toluene. Discussion in this section has been confined mainly to experimental points. In the third section, the 'Discussion', the results are dealt with, not in the chronological order in which they were obtained, but in a sequence which permits a more satisfactory treatment. AS the Information obtained from the studios on fluorine is required in the discussion of the diphenylmetgane results it is considered first. Then an examination is made of data from other investigations in order to assess what products might have been expected from the pyrolysis of diphenyl methane, and this is followed by a consideration of the results of the present work carried out on this compound. Board dissolution energies have been derived for the methylenic C-H bond in fluorene and in disphenylmethane, also for the central C-C bond in tetraphenylethane. A mechanics is proposed for the decomposition of diphenylmethyl bromide but the limited experimental date does not permit a definite conclusion to be reached. An account of the method of analysis of the ultra-violet absorption curves of the toluene pyrolysis products precedes a brief resume of the limitations of the method of analysis by ultra-violet spectrophotometric examination of the mixtures resulting from hydrocarbon pyrolysis. The section is concluded with a short account concerning the existence of unsaturated diner analogues in the thermal decomposition products of hydrocarbons. In the 'Appendix' details are given of thermochemical and kinetic calculations, the results of which are used in the 'Discussion' section.

This thesis describes the design and construction of a close range Passive Millimetre Wave (PMMW) scanning thermal imager. Whilst close range PMMW imager has previously been applied to concealed weapon detection at ranges of a few metres, the imager described herein is designed to focus on targets at a range of a few tens of centimetres. In particular, the main design aim was to produce higher resolution thermal maps suitable for medical imaging applications. Imaging at MMW frequencies offers greater penetration depths in lossy dielectric media than conventional infrared imagers, although there is an obvious trade-off in spatial resolution. The instrument consists of a total power radiometer operating at a centre frequency of 94 GHz. The input to the radiometer is provided by a quasi-optical focussing lens, designed using Gaussian Bean Mode theory. The observed scene is scanned by means of a rotating mirror and a translation table. Image acquisition timescales were of the order of a few minutes. Thermal calibration of the radiometer output was performed by recording the image of adjacent hot and cold reference loads with each line scan. In addition, the thermal transition between the calibration loads was used to measure the beam profile of the input optics and the Modulation Transfer Function (MTF) of the instrument. The imager has shown that it is possible to produce useful close range thermal images of the human body at MMW frequencies. The spatial resolution achieved was approximately 3 mm, with a thermal resolution of 0.4 K.

A development over the past 70 to 80 years within scientific research has been the need for very large pieces of apparatus to enable the exploration of new scientific topics, particularly within particle physics and space science. These ‘megascience projects' are generally undertaken as cooperative ventures by countries seeking to pursue scientific experimental opportunities in these fields. Such projects, a subcategory of large/megaprojects that have a minimum budget of one billion US dollars, are characterised by high levels of technological uncertainty, given that their success depends on the development of new, highly-advanced technologies . However, there is a notable lack of research into the leadership of megascience projects - an important consideration when embarking on a substantial project. The leadership literature traditionally categorises leaders into five discrete leadership styles, but there is a gap when it comes to understanding the characteristics and development of leaders of megascience projects. In this thesis, I address this gap in knowledge, focusing on three research questions: (1) What are the characteristics of those who lead megascience projects? (2) Where were their leadership skills developed? (3) And how were their leadership skills developed? A useful concept during the intellectual journey to answer these questions was ‘the heterogeneous engineer', which provided the original conceptual framework for this thesis. I use a combination of archival and interview-based research to answer these research questions in the cases of the Tevatron at Fermilab in the United States, and the Large Hadron Collider (LHC) at CERN on the Franco-Swiss border near Geneva. This archival research notably required access to normally restricted sections of the CERN archives related to the LHC. The thematic analysis conducted for this research yielded various findings that include the primacy of technical competence as a foundation for respect, along with strong management ability, the importance of trustworthiness, and team empowerment. Furthermore, I found that leadership training within megascience projects is experiential in nature, with formal leadership training programmes acting at most in a support role. During the analysis of my data, I concluded that the heterogeneous engineer concept was based on a relative anomaly, making it difficult to use this concept as the foundation for a more generalised leadership theory. One unexpected finding, which represents a relatively original contribution of this thesis, is the tailoring of senior leadership selection to suit a specific project phase, something which appears to partially contradict the current literature. I identify four phases, the characteristics of leaders best equipped for each phase, and the implications for other large projects.

All over the world, corporate scandals, big and small, affect our daily life. Since the beginning of the 21st century, major American corporations including WorldCom, Enron, Dynegy, Merk, Tyco, Lucent Technologies, Merrill Lynch, Global Crossing, and Health South were involved in corporate scandals. In Europe, accounting fraud and other criminal activities were uncovered at Switzerland¡¦s Adecco, the Netherlands¡¦ Ahold, and Parmalat, the Italian dairy concern whose owners defrauded investors of billions of dollars, including more than 1.5 billion US dollars from American investors. Crisis management is often portrayed as reactive activity directed at problems, usually arising from human error, and already escalating. The development of a crisis is often indeterminate rather than fixed. Crisis management can mean quick actions that prevent a triggering event as it unfolds or delayed action that mops up after the triggering event has run it course. In this paper, the proposed crisis management model is the M3 theory for managing multiple mistakes derived from Robert E. Mittelstaedt, Jr.¡¦s book, ¡§Will Your Next Mistake Be Fatal? Avoiding the Chain of Mistakes That Can Destroy Your Organization.¡¨ In this book, Mittelstaedt addresses errors in preparation, execution, strategy, and culture. He emphasizes that firms need to build internal control systems that will trigger clear and actionable alarms before ¡§failure chains¡¨ accelerate beyond control. The process of Managing Multiple Mistakes (M3) can determine whether an organization ends up in a negative or positive light on the front page of a national newspaper. ¡§The concept of Managing Multiple mistakes," Mittelstaedt writes, ¡§is based on the observation that nearly all serious accidents, whether physical or business, are the result of more than one mistake. If we do not ¡¥break the chain¡¦ of mistakes early, the damage that is done, and its cost, will go up exponentially¡K until the situation is irreparable.¡¨

The electrochemical, thermal and structural properties of polyethylene oxide (PEO) based polymer electrolytes containing multivalent ions were investigated. The phase diagram for the PEO:Ca(CF3SO3)2 system was determined by x-ray diffraction and differential scanning calorimetry techniques. Precipitation of the salt from the system at high temperatures was directly observed by variable temperature x- ray diffraction. This was ascribed to a negative entropy of dissolution of the salt in the polymer. A new crystalline complex PEO6Ca(CF3SO3)2, which exhibits a phase transition between two polymorphic forms was observed. The temperature dependence of ionic conductivity was related to the phase diagram. Redox behaviour of the PEO:Nil2 system was probed. Motion of the Ni(II) species through the system was extremely slow as evidenced by the low effective diffusion coefficient (1.82 x 10 11 cm 2s−1) and cationic current fraction (F+ < 0.1). Deposition of nickel from the polymer was characterised by instantaneous nucleation followed by three dimensional diffusion controlled growth. Investigation of the redox behaviour of the PE0:Eu(CF3SO3)3 system indicated that reduction of Eu3+ followed an ec mechanism. Evidence was obtained for extremely slow diffusion of Eu3+ containing species (D[sub]eff ~ 3.66 x 10 −16cm2s−1) through the system and slow kinetics of electron transfer. Thermal studies of the PEO:Co(SCN)2 system indicated that the glass transition temperature (Tg) was grossly elevated by the presence of Co(SCN)2 in the polymer. The absence of a crystalline PEO:Co(SCN)2 complex was ascribed to the high Tg which leads to slow crystallisation kinetics. UV-visible spectra indicated that the Co2+ ion was tetrahedrally coordinated in the system at low salt concentrations. The structure of the PEO3NaClO4 crystalline complex was reported as a subsidiary study.

A sucrose gradient technique was developed for the preparation of plasma membrane material from SV40 3T3, Py3T3 and HeLa cells. A modification of this method yielded purified nuclei. The plasma membrane material, which was enriched in both 5'-nucleotidase and (Na+K)-ATP ase activities, was used to establish some of the properties of the latter in 3T3 and SV40 3T3 cells. Many of these properties were similar in both cell lines. The effect of conditioning of the growth medium, on the transport of 86Rb into 3T3 and SV40 3T3 cells was investigated. It was shown that conditioning reduced the uptake from growth media and that when the cells were then transferred to Krebs solution, the uptake was apparently increased. The effect of cell population density on several of the properties of 3T3, SV40 3T3, Py3T3 and HeLa cells was examined. When transformed 3T3 cells were grown in medium containing 10% calf serum, the activities of the cell surface enzymes, (Na+K)-ATPase and 5'-nucleotidase, decreased differently with increasing density. The (Na+K)-ATPase activity decreased sharply as the density exceeded 5 x 10⁴ cells/cm2 while the 5'-nucleotidase activity decreased gradually as the density increased. The activity of the latter plateaued so that the overall decrease in the activities of both enzymes was similar. When 3T3 cells were grown under the same conditions, the activities of the cell surface enzymes increased with cell population density. The cell surface enzymes of HeLa cells were shown to decrease with density in a manner similar to those of the transformed 3T3 cells but the decrease in the (Na+K)-ATPase did not exactly follow that of the specific ouabain binding. The effect of culture density on the intracellular enzyme was shown to depend on the cell type as well as the particular enzyme. In all of the 3T3 cell lines, the acid phosphatase activity was observed to increase with increasing density whereas in HeLa cells this enzyme did not alter. In the transformed 3T3 cell lines, the monoamine oxidase activity did not alter with density and the rotenone insensitive NADH-ferricyanide reductase activity increased but in 3T3 cells, the former increased and the latter decreased. In foetal calf serum, the cell surface enzymes were observed to alter differently with respect to cell population density. The cell protein tended to decrease as did the cell volume but these measurements were not directly related. The specific Concanavalin A binding also decreased with cell population density but the decreases were not related to the volume changes. It was concluded that the activity of many of the enzymes of cultured cells is dependent both on the cell population density and the medium in which the cells are grown.

Experiments 3 to 12 show that certain kinds of visuospatial material will differentially disrupt a visual memory strategy, even though subjects are instructed that the material is irrelevant. This irrelevant pictures effect is shown with a wide range of visual material including dynamic visual noise (Experiments 3 to 7 and 9 to 12), line drawings of common objects (Experiments 3 and 8), three by three matrices with the cells randomly black or white (Experiment 7) and a single dot that consecutively appears in five different positions in space (Experiment 12). The irrelevant pictures effect can also be demonstrated with two visual memory strategies that are qualitatively different from each other, the pegword mnemonic strategy and the method of loci strategy (Experiment 11). This robust irrelevant pictures effect is used as a tool for investigating visual working memory and the results of Experiments 1 to 12 are presented as being broadly consistent with Logie's 1995 two-component model of visual working memory comprising a visual cache and an inner scribe. The irrelevant pictures effect is evidence for the existence of the visual cache into which visual material is thought to have obligatory access. Experiment 9 demonstrates that static noise causes no interference with visual memory. Serially presented static noise in Experiment 10 does, however, selectively disrupt the visual strategy. It is hypothesised that the difference between the effect of the static pattern and the re-presented static pattern reflects the decay function of the visual cache. There is also support for the inner scribe part of the model. The star dots in Experiment 11 are thought to disrupt the pegword mnemonic strategy because both draw on common resources within the inner scribe. Moreover, Experiment 11 shows that the two components of Logie's 1995 model of visuospatial working memory can be empirically distinguished within one experiment. It shows that a visual task which requires access to the rehearsal component is disrupted by a concurrent, irrelevant spatial task as well as a concurrent, irrelevant visual task. In contrast, a visual task that requires little access to the rehearsal mechanism is not disrupted by a concurrent spatial task but is disrupted by a concurrent visual task. There are, however, also circumstances when the irrelevant visuospatial material disrupts visual and verbal memory strategies in a more general way, making attentional demands on the central executive part of working memory that are additional to those required to carry out the memory strategies. Three experiments look at this general effect of irrelevant pictures. Results suggest that the factors responsible for the placing of general demands on the central executive's attentional resources involve a focused, sufficiently unexpected change (Experiment 7) at the encoding stage of information processing (Experiment 8).

The thermal equilibrium and evolution of coronal structure is studied in this thesis. A symmetric and constant cross-sectional coronal loop is considered and, because of the strong magnetic field, the plasma is confined to move along the field lines, so that a one-dimensional problem can be assumed. We begin by giving a brief description of the Sun and corresponding phenomena. Then a discussion of the basic MHD equations is given. Here, it is assumed that the heating function is spatially dependent and the cooling function is due to an optically thin plasma. The thermal equilibrium of uniform-pressure coronal loop is investigated. The effects due to varying the values of the parameters involved in the governing equations are studied. It is found that there is a critical decay length of the heating below which a hot coronal loop does not exist. It is suggested that thermal non-equilibrium occurs, allowing the existence of catastrophic cooling. A study of the stability of the equilibrium up to the second order approximation is presented, and it is found that the response of the structure not only depends on the amplitude of the disturbance, but also on whether the disturbance increases or decreases the static temperature. The thermal evolution of the above structure is also investigated by assuming that the inertial terms are small. The previous results related to the critical heating decay length are verified. The numerical simulation shows that an initial hot plasma evolves to a new equilibrium which has a cool summit. This equilibrium is identified as a prominence-like solution. Further investigations are made in order to show how the structure can either evolve to a hot or a cool summit temperature depending on whether the initial conditions are above or below threshold values. The evolution of a disturbance increasing or decreasing an initial equilibrium temperature is followed numerically verifying the prediction made in the stability analysis. Furthermore, the effect of gravity is considered in the thermal equilibrium of loop. Similar results were found as studied for a constant-pressure loop. However, it was found that the critical values in which thermal non-equilibrium can occur is increased. A magnetic dip is also included in this model and the thermal equilibrium is studied. Finally, extensions of the present work is presented and some preliminary results are discussed.

A brief introduction to the problem and importance of solid-solid contact as well as to the nature of surface topography is given. A number of experimental techniques, both direct and indirect, for determining the true area of contact between surfaces as well as a number of theories for predicting contact areas in the case of elastic, plastic, and elasto-plastic deformation of contacting surface asperities are reviewed. The effect of tangential loading upon the area of contact is also reviewed. In order to implement a previously established goal of observing the nature of contact between transparent models of scaled-up surfaces, a procedure for three-dimensional model design, a technique for model fabrication, and an experimental apparatus have been developed. A computer program to predict points of contact and elastic contact parameters between macroscopic surface models is presented. Determining the range of application of the Hertz equations is discussed. The computer program is used to predict the contact parameters between the three-dimensional surface models developed. For this situation the nature of contact was found to vary from the case of a single pair of asperities dominating elastic contact to the case of multiple asperity contact between several pairs of contacting asperities. / Master of Science

In this thesis I have analysed several mathematical models, which represent the dynamics of genetic regulatory networks. Methods of bifurcation analysis and direct numerical simulations were employed to study the biological phenomena that can occur due to the presence of time delays, such as stable periodic oscillations induced by Hopf bifurcations. To highlight the biological implications of time-delayed systems, different models of genetic regulatory networks as relevant to the onset and development of cancer were studied in detail, as well as genetic regulatory networks which describe the effects of transcription factors in the immune system. A network of an oscillator coupled with a switch was explored, as systems such as these are prevalent in genetic regulatory networks. The effects of time delays on its oscillatory and bistable behaviour were then investigated, the results of which were compared with available results from the literature.