Boundary Value Problems in Elasticity and Thermoelasticity

In this dissertation the author solves a series of mixed boundary value problems arising from crack problems in elasticity and thermoelasticity. Using integral transform techniques and separation of variables appropriately, it is shown that the solutions can be found by solving a corresponding set of triple or dual integral equations in some instances, while in others the solutions of triple or dual series relations are required. These in turn reduce to various singular integral equations which are solved in closed form, in two cases, or by numerical methods. The stress intensity factors at the crack tips, the physical parameters of interest, are found and the results are recorded in both tabular and graphical form

The variation in pressures exerted by commercially available compression garments

Commercially available compression garments (CGs) demonstrate the enhanced recovery from exercise in some, but not all studies. It is possible that in some cases the degree of compression pressure (ComP) exerted is not sufficient to produce any physiological benefit. The aim of this investigation was to identify the levels of ComP exerted by commercially available CGs. This study was composed of two parts. In part A 50 healthy, physically active individuals (n=26 male, n=24 female) were fitted with CGs according to manufacturer’s guidelines. ComP was measured in participants standing in the anatomical position with a pressure measurement device inserted between the skin and the garment. Data were compared to ‘ideal’ pressure values proposed in the literature. In part B ComP in three different brands of CG were compared in a population of 29 men who all wore a medium sized garment. A one way ANOVA indicated that there was a significant difference (P0.05) between observed and ideal pressures in the calf of the male population. No significant differences in pressure (P>0.05) were observed between CG brands at the quadriceps or calf. In conclusion a large number of individuals may not be experiencing an adequate ComP from CG, and this is true for all 3 of the major brands of CGs tested in this investigation

Re-estimation of argon isotope ratios leading to a revised estimate of the Boltzmann constant

In 2013, NPL, SUERC and Cranfield University published an estimate for the Boltzmann constant [1] based on a measurement of the limiting low-pressure speed of sound in argon gas. Subsequently, an extensive investigation by Yang et al [2] revealed that there was likely to have been an error in the estimate of the molar mass of the argon used in the experiment. Responding to [2], de Podesta et al revised their estimate of the molar mass [3]. The shift in the estimated molar mass, and of the estimate of kB, was large: -2.7 parts in 106, nearly four times the original uncertainty estimate. The work described here was undertaken to understand the cause of this shift and our conclusion is that the original samples were probably contaminated with argon from atmospheric air.
 In this work we have repeated the measurement reported in [1] on the same gas sample that was examined in [2, 3]. However in this work we have used a different technique for sampling the gas that has allowed us to eliminate the possibility of contamination of the argon samples. We have repeated the sampling procedure three times, and examined samples on two mass spectrometers. This procedure confirms the isotopic ratio estimates of Yang et al [2] but with lower uncertainty, particularly in the relative abundance ratio R38:36.
 Our new estimate of the molar mass of the argon used in Isotherm 5 in [1] is 39.947 727(15) g mol-1 which differs by +0.50 parts in 106 from the estimate 39.947 707(28) g mol-1 made in [3]. This new estimate of the molar mass leads to a revised estimate of the Boltzmann constant of kB = 1.380 648 60 (97) × 10−23 J K−1 which differs from the 2014 CODATA value by +0.05 parts in 106.&#13

Seismological studies of upper crustal structure of the southern Midland Valley of Scotland

No abstract available

C-H...N hydrogen bonding in an overlayer of s-triazine physisorbed on a graphite surface

The structure of a crystalline monolayer of 1,3,5-triazine has been characterised using X-ray diffraction. The monolayer is found to exhibit a hexagonal unit cell with a lattice parameter of 6.161(5) Å, indicating the formation of C–H…N hydrogen bonds. DFT simulations have been performed exhibiting close agreement with the experimental structure. By comparing the strength of the intermolecular interactions both with and in the absence of Van der Waals corrections, it is possible to estimate an interaction strength for the weak C–H…N hydrogen bonds.We acknowledge financial support for JAD from an Engineering and Physical Sciences Research Council (EPSRC) DTA studentship award from the Department of Chemistry, University of Cambridge

The Developing Law Governing Employee and Employer Rights Relating to Use of Electronic Media Within and Outside the Workplace

Employees are using electronic media at an increasing rate to communicate with others both in and out of the workplace. While email, social networking sites, blogs, text messages, and online videos may seem to present new and complex challenges for employees and employers, the decisional law suggests that the key to understanding issues presented by electronic media use is to reason by analogy to more “traditional” means of communication. For example, an email string between two people or among a group may be viewed similarly to an in-person conversation; the former is just memorialized in writing. A comment posted on an employee’s Facebook page may be treated like a verbal comment made by an employee to friends and coworkers. The same fundamental questions come up in the cases involving traditional or electronic communications: What was communicated? Who communicated it? When was it communicated? To whom was it communicated

Influence of grille spacing on the uplift behaviour of steel grillages for OHLs

The increasing development of renewable energy (e.g. on and offshore wind) has increased the demand on existing electricity transmission networks in the UK. However, the remoteness of the transmission network, particularly in Scotland, makes upgrade and renewal, both economically and environmentally challenging, with often highly restrictive access constraints. Steel grillages are an alternative non-concrete foundation that can be loaded immediately post-backfill and transported to remote locations using low-ground pressure vehicles or helicopters. This paper investigates the optimisation of steel grillages for overhead line foundations such that the uplift load-displacement response is comparable to solid foundations (i.e. a concrete pad). Initial 1g uplift tests have shown that the optimal grille-spacing-to-width ratio (/) for a comparable ultimate uplift capacity to a solid plate lies within 1 < / < 2

2D constraint modifies packing behaviour: a halobenzene monolayer with X3 halogen-bonding motif.

Using a combination of X-ray diffraction and simulation techniques, we are able to identify a crystalline monolayer of 1,3,5-triiodotrifluorobenzene formed on graphite. The monolayer is found to exhibit an incommensurate hexagonal unit cell with a lattice parameter of 9.28(7) Å, exhibiting a trigonal arrangement of iodine atoms not found in the bulk structure. DFT simulations have been performed exhibiting close agreement with the experimental structure. Importantly these simulations can be used to compare the strength of the intermolecular interactions both with and without Van der Waals corrections. Thus it is possible to estimate that halogen bonding consists of approximately half the total interaction energy. This demonstrates that despite the presence of strong directional non-covalent bonding, dispersion interactions account for a very significant proportion of the total energy

Air–vacuum transfer; establishing traceability to the new kilogram

The redefinition of the kilogram, along with another three of the base units of the International System of Units (SI), is scheduled for 2018. The current definition of the SI unit of mass assigns a mass of exactly one kilogram to the International Prototype of the kilogram, which is maintained in air and from which the unit is disseminated. The new definition, which will be from the Planck constant, involves the realisation of the mass unit in vacuum by the watt balance or Avogadro experiments. Thus, for the effective dissemination of the mass unit from the primary realisation experiments to end users, traceability of mass standards transferred between vacuum and air needs to be established and the associated uncertainties well understood. This paper describes a means of achieving the link between a unit realised in vacuum and standards used in air, and the ways in which their use can be optimised. It also investigates the likely uncertainty contribution introduced by the vacuum air transfer process