EDDY CURRENT DETECTION OF Al-Si PENETRATIONS IN CANNED SLUGS

An instrument for detecting Al-Si alloy penetrations in the Al jacket of fuel slugs is described. The instrument is of the eddy current type, and the sensing element is a small probe that does not touch the specimen under inspection. Al-Si inclusions 0.020 in. in diameter that penetrate to within 0.005 in. of the can surface can be detected. The response of the circuits is such that a slug 8 in. long can be scanned in 45 sec. (auth

Search for Large Rapidity Gap Events in e^+ e^- Annihilation

We investigate the cross-section for the production of a low-mass colour-singlet cluster in $e^+e^-$ annihilation with a large rapidity gap between the colour-singlet cluster and the other jets. It is argued that such events are the cross-channel analogue of large-rapidity-gap events in deep-inelastic scattering, and therefore could in principle be used to investigate the analytic continuation of the BFKL pomeron to the positive-$t$ kinematic regime, where one would expect the trajectory to pass through glueball states. The cross section can be calculated in perturbative QCD, so that the infrared scale arising from non-perturbative effects, which prevents an exponential fall-off with rapidity gap in the case of deep-inelastic scattering, is absent in $e^+ e^-$ annihilation. Correspondingly, the cross section for such events decreases rapidly with increasing rapidity gap.Comment: LATEX file - 21 pages + 15 figure

Duality between Electric and Magnetic Black Holes

A number of attempts have recently been made to extend the conjectured $S$ duality of Yang Mills theory to gravity. Central to these speculations has been the belief that electrically and magnetically charged black holes, the solitons of quantum gravity, have identical quantum properties. This is not obvious, because although duality is a symmetry of the classical equations of motion, it changes the sign of the Maxwell action. Nevertheless, we show that the chemical potential and charge projection that one has to introduce for electric but not magnetic black holes exactly compensate for the difference in action in the semi-classical approximation. In particular, we show that the pair production of electric black holes is not a runaway process, as one might think if one just went by the action of the relevant instanton. We also comment on the definition of the entropy in cosmological situations, and show that we need to be more careful when defining the entropy than we are in an asymptotically-flat case.Comment: 23 pages, revtex, no figures. Major revision: two sections on the electric Ernst solution adde

A computational framework for modelling micro-scale fluids in the presence of surface tension

Immunisation, pioneered by Edward Jenner (1749-1823), has saved millions of lives and has helped the human race survive several disease pandemics. Today, the immunisation industry conducts vast amounts of research, not only developing new vaccinations, but also new methods of diagnosis. Currently, blood samples are taken manually using a syringe, loaded into a centrifuge and spun for several hours to separate out the different parts of the blood sample. These parts can then be tested manually for a range of ailments. In some areas of the world, access to such a device is unavailable and even if it was, this can be a long, energy intensive and costly process. Hence, new faster methods involving the use of microchips and surface acoustic waves and are an inviting possibility. Utilising the field of fluid dynamics, notably the work of Newton, Euler, Cauchy, Navier and Stokes, combined with modern computational methods allows for an engineering perspective to be taken on this problem. This thesis combines many novel contributions to create a computational modelling framework to model external excitation of axisymmetric micro-scale fluid droplets. In the present work fluid motion is governed by an axisymmetric form of the Navier-Stokes equations, with focus on incompressible Newtonian fluids, and this is presented in full. At the micro-scale, surface tension is the most dominant force, hence additional contributions are derived and included due to surface tension and contact line forces. Additionally, to reduce spurious oscillations within the pressure field, the pressure Laplacian stabilisation (PLS) technique is implemented. A derivation of the technique as well as an investigation into the effect of the stabilisation parameter is presented. The kinematics of the system are of great importance. At the micro-scale, tracking of the surface of the fluid is highly desirable and most advantageous, and the choice of kinematic description must reflect this. Unlike more traditional computational methods adopting an Eulerian description or a Lagrangian description of the governing equations, the presented computational framework makes use of the Arbitrary Lagrangian Eulerian (ALE) description. The ALE formulation avoids many of the drawbacks of traditional methods whilst allowing for accurate tracking of the fluid surface and minimising the requirement for frequent remeshing. Taking the current, deformed, configuration as the reference configuration in an Updated Lagrangian (UL) manner, combines into a kinematic description termed the Updated Arbitrary Lagrangian Eulerian (UALE) formulation. The physics underlying this formulation are presented in detail within this thesis. Several problems, examining a range of droplet volume, contact angle and experimental configuration are presented to validate the computational framework against analytical solutions. Of the various problems examined, all show a very good correlation to analytical solutions. Differences, if any, are attributed to the density of the mesh, which is shown to alter the amplitude but not the frequency of oscillation, or over-simplification made in the analytical solutions. Lastly, a new hypothesis is tested which until recently was extremely difficult to verify. The current hypothesis in the literature proposes that upon reaching the fluid-solid inter- face, surface acoustic waves propagate through the fluid causing motion. Conversely, the new hypothesis proposes that upon reaching the fluid-solid interface, surface acoustic waves propagate capillary waves up the surface of the droplet, changing the apparent wetting angle and inducing motion. This is implemented by changing the contact angle in time to simulate the action of surface acoustic waves and the resulting analysis recorded the occurrence of jetting thereby confirming the hypothesis. Further testing can be conducted and this technology utilised in the development of new disease diagnosis devices. The computational framework has been very successful in modelling a range of micro-scale problems. Further development of this framework will allow for a greater understanding of the effect of surface acoustic waves on a fluid droplet. In turn, this will allow for the improved design of surface acoustic wave devices

Trends in sexually transmitted infections in general practice 1990-2000: population based study using data from the UK general practice research database

Objective: To describe the contribution of primary care to the diagnosis and management of sexually transmitted infections in the United Kingdom, 1990-2000, in the context of increasing incidence of infections in genitourinary medicine clinics. Design: Population based study. Setting: UK primary care. Participants: Patients registered in the UK general practice research database. Main outcome measures: Incidence of diagnosed sexually transmitted infections in primary care and estimation of the proportion of major such infections diagnosed in primary care. Results: An estimated 23.0% of chlamydia cases in women but only 5.3% in men were diagnosed and treated in primary care during 1998-2000, along with 49.2% cases of non-specific urethritis and urethral discharge in men and 5.7% cases of gonorrhoea in women and 2.9% in men. Rates of diagnosis in primary care rose substantially in the late 1990s. Conclusions: A substantial and increasing number of sexually transmitted infections are diagnosed and treated in primary care in the United Kingdom, with sex ratios differing from those in genitourinary medicine clinics. Large numbers of men are treated in primary care for presumptive sexually transmitted infections

Role of DNA sequences outside the cores of DNase hypersensitive sites (HSs) in functions of the β-globin locus control region. Domain opening and synergism between HS2 and HS3

The roles of each DNase hypersensitive site (HS), and the DNA sequences between them, in the activity of the locus control region of the mammalian β-globin gene domain were examined by placing human and rabbit restriction fragments containing the cores of HS2, HS3, HS4, and HS5, along with varying amounts of flanking DNA, upstream of a hybrid ε-globin-luciferase reporter gene and testing for effects on expression both prior to and after integration into the chromosomes of K562 cells, a human erythroid cell line. Prior to integration, fragments containing HS2 enhanced expression to the greatest extent, and the modest enhancement by some fragments containing HS3 correlated with the presence of a well-conserved binding site for AP1/NFE2. The stronger effects of larger locus control region DNA fragments in clones of stably transfected cells indicates a role for sequences outside the HS cores after integration into the genome. The strong effect of a 1.9-kilobase HindIII fragment containing HS3 after, but not prior to, integration argues for the presence of a chromatin domain-opening activity. Use of a rabbit DNA fragment containing both HS2 and HS3 demonstrated a synergistic interaction between the two HSs when their natural context and spacing are preserved

Consistent Anisotropic Repulsions for Simple Molecules

We extract atom-atom potentials from the effective spherical potentials that suc cessfully model Hugoniot experiments on molecular fluids, e.g., $O_2$ and $N_2$. In the case of $O_2$ the resulting potentials compare very well with the atom-atom potentials used in studies of solid-state propertie s, while for $N_2$ they are considerably softer at short distances. Ground state (T=0K) and room temperatu re calculations performed with the new $N-N$ potential resolve the previous discrepancy between experimental and theoretical results.Comment: RevTeX, 5 figure

What Makes Some People Think Astrology Is Scientific?

Citizens in both North America and Europe are apt to read horoscope columns in newspapers and magazines. While some people read these casually and purely for entertainment, some believe that astrology has scientific status and can provide real insight into events and personality. Using data from a European survey, this article explores some of the reasons why some people think that astrology is scientific and how astrology is viewed in relation to other knowledge-producing practices. Three hypotheses in particular are tested. The first is that some Europeans lack the necessary scientific literacy to distinguish science from pseudoscience. The second is that people are confused about what astrology actually is. The third is derived from Adorno’s work on authoritarianism and the occult and postulates that those who adhere to authoritarian values are more likely to believe in astrological claims. Support is found for all three hypotheses. </jats:p