Fatigue of friction stir welded 2024-T351 aluminium alloy

Fatigue failure characteristics of friction stir welds in 13mm gauge 2024-T351 plate have been assessed. Failure occurred from either the weld region (nugget/flow arm) or from the material immediately surrounding the weld. Fatigue failure from the surrounding material was essentially conventional, initiating from large S-phase intermetallic particles and growing in a macroscopic mode I manner. Corresponding fatigue lives were seen to be comparable to parent plate and results previously reported for similar welds in thinner plate. Failure over the weld region was identified with discontinuities in the macroscopic flow pattern of the weld flow arm. Subsequent crack growth showed pronounced macroscopic crack deflection around the ‘onion ring’ structure of the weld nugget. The bands making up the onion rings were identified with variations in local hardness levels, consistent with a mechanical contribution to the crack deflection process

The choice among non-callable bonds and make whole, claw back and otherwise ordinary callable bonds

This paper seeks to explain determinates of the choice and the pricing of various types of callable and non-callable bonds. We find that the popularity of different types of callable and non-callable bonds is significantly related to the economic environment. In addition, the popularity of claw back bonds appear to be driven by agency considerations, make whole bonds by the debt overhang problem, ordinary callable bonds by the need by banks to deal with interest rate changes and non-callable bonds by the need to raise funds as cheaply as possible. All else equal, firms pay a higher offer spread for the flexibility to call a claw back bond early via a new share offering whereas issuers of make whole bonds are rewarded with a lower offer spread for restricting calls to circumstances that does not expropriate bondholder wealth

Properties of the mechanosensitive channel MscS pore revealed by tryptophan scanning mutagenesis

Funding This work was supported by a Wellcome Trust Programme grant [092552/A/10/Z awarded to I.R.B., S.M., J. H. Naismith (University of St Andrews, St Andrews, U.K.), and S. J. Conway (University of Oxford, Oxford, U.K.)] (T.R. and M.D.E.), by a BBSRC grant (A.R.) [BB/H017917/1 awarded to I.R.B., J. H. Naismith, and O. Schiemann (University of St Andrews)], by a Leverhulme Emeritus Fellowship (EM-2012-060\2), and by a CEMI grant to I.R.B. from the California Institute of Technology. The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013 FP7/2007-2011) under Grant PITN-GA-2011-289384 (FP7-PEOPLE-2011-ITN NICHE) (H.G.) (awarded to S.M.).Peer reviewedPublisher PD

Theory of long range interactions for Rydberg states attached to hyperfine split cores

The theory is developed for one and two atom interactions when the atom has a Rydberg electron attached to a hyperfine split core state. This situation is relevant for some of the rare earth and alkaline earth atoms that have been proposed for experiments on Rydberg-Rydberg interactions. For the rare earth atoms, the core electrons can have a very substantial total angular momentum, $J$, and a non-zero nuclear spin, $I$. In the alkaline earth atoms there is a single, $s$, core electron whose spin can couple to a non-zero nuclear spin for odd isotopes. The resulting hyperfine splitting of the core state can lead to substantial mixing between the Rydberg series attached to different thresholds. Compared to the unperturbed Rydberg series of the alkali atoms, the series perturbations and near degeneracies from the different parity states could lead to qualitatively different behavior for single atom Rydberg properties (polarizability, Zeeman mixing and splitting, etc) as well as Rydberg-Rydberg interactions ($C_5$ and $C_6$ matrices)

New approaches to the measurement of chlorophyll, related pigments and productivity in the sea

In the 1984 SBIR Call for Proposals, NASA solicited new methods to measure primary production and chlorophyll in the ocean. Biospherical Instruments Inc. responded to this call with a proposal first to study a variety of approaches to this problem. A second phase of research was then funded to pursue instrumentation to measure the sunlight stimulated naturally occurring fluorescence of chlorophyll in marine phytoplankton. The monitoring of global productivity, global fisheries resources, application of above surface-to-underwater optical communications systems, submarine detection applications, correlation, and calibration of remote sensing systems are but some of the reasons for developing inexpensive sensors to measure chlorophyll and productivity. Normally, productivity measurements are manpower and cost intensive and, with the exception of a very few expensive multiship research experiments, provide no contemporaneous data. We feel that the patented, simple sensors that we have designed will provide a cost effective method for large scale, synoptic, optical measurements in the ocean. This document is the final project report for a NASA sponsored SBIR Phase 2 effort to develop new methods for the measurements of primary production in the ocean. This project has been successfully completed, a U.S. patent was issued covering the methodology and sensors, and the first production run of instrumentation developed under this contract has sold out and been delivered

Control system for hunger and its implications in animals and man

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Shuttle GPS R/PA evaluation analysis and performance tradeoff study

Primary responsibility was understanding and analyzing the various GPS receiver functions as they relate to the shuttle environment. These receiver functions included acquisition properties of the sequential detector, acquisition and tracking properties of the various receiver phase locked loops, and the techniques of sequential receiver operation. In addition to these areas, support was provided in the areas of oscillator stability requirements, antenna management, and navigation filter requirements, including preposition aiding

IASME: Information Security Management Evolution for SMEs

Most of the research in information risk and risk management has focused on the needs of larger organisations. In the area of standards accreditation, the ISO/IEC 27001 Information Risk Management standard has continued to grow in acceptance and popularity with such organisations, although not to a significant extent with SMEs. An interesting product recently developed for ENISA (European Nations Information Security Association) based on the Carnegie-Mellon maturity model and aimed at SMEs has not so far filled the gap. In this paper, a researcher and two practitioners from the UK discuss an innovative development in the UK for addressing the information assurance needs of smaller organisations. They also share their perceptions about the security of national information infrastructures, and concerns that SMEs do not get the priority that their position in the supply chain would suggest they should have. The authors also explore the development and roll out of IASME (Information Assurance for SMEs), which they have developed in the context of a tight market, where spare cash is in short supply, and many SMEs are still in survival mode. The question for the business is therefore not seen as “can we afford to spend on information security” but “can we afford not to spend…” As well as the effect on being able to do business at all of having an SMEs systems compromised, there are also matters of reputation, and the growing threat of fines as a result of not complying with laws and regulations. The paper concludes with achievements of real businesses using the IASME process to cost-effectively achieve information assurance levels appropriate for themselves