Moving body velocity arresting line

The arresting of a moving body is improved through the use of steel cables that elongate to absorb the kinetic energy of the body. A sleeve surrounds the cables, protecting them from chafing and providing a failsafe energy absorbing system should the cables fail

An introduction to the new Productivity Information Management System (PIMS)

The productivity information management system (PIMS), is described. The main objective of this computerized system is to enable management scientists to interactively explore data concerning DSN operations, maintenance and repairs, to develop and verify models for management planning. The PIMS will provide a powerful set of tools for iteratively manipulating data sets in a wide variety of ways. The initial version of PIMS will be a small scale pilot system. The following topics are discussed: (1) the motivation for developing PIMS; (2) various data sets which will be integrated by PIMS; (3) overall design of PIMS; and (4) how PIMS will be used. A survey of relevant databases concerning DSN operations at Goldstone is also included

This Girl Can: An Ecological Approach to Investigating Physical Activity in Urban Females

Despite the widely documented physical, psychological and social benefits associated with physical activity, 86% of young females in the UK are insufficiently active (Sport England 2018). In order to improve physical activity levels among young females aged 14-25 in the London Borough of Lambeth, the local council partnered with five physical activity providers and our research team. Together we embarked on the This Girl Can Lambeth project which was inspired by the national campaign This Girl Can. Our role in the project was to evaluate its implementation and outcomes, and additionally to identify barriers and facilitators to participation for this population. We wanted to capture the intrapersonal and interpersonal factors that are often described in literature, but also the relevant environmental, organisational and legislative factors, therefore we used an ecological framework to guide our research. A systematic review of literature showed that the majority of interventions aimed at young females take place in educational settings and focus on either physiological or psychological intrapersonal factors. In an intervention study we compared a physical education program with a school-based intervention program, to investigate its effects on the behaviour and health of young females. Although the intervention program included multi-sports, and encouraged the building of rapport and a foundation for sustained participation in community-based exit routes, we found no clear benefit of the intervention program over physical education. In subsequent qualitative studies we investigated what was amiss. We conducted focus groups with young females who had participated in the intervention programs to understand what factors they perceived to influence their participation. The focus groups highlighted organisational and environmental factors as primary barriers to physical activity. Such factors are stable features of their lives making them difficult barriers to overcome. However, when we interviewed the physical activity providers, the barriers to participation that they perceived were quite different. They identified intrapersonal factors such as self-efficacy and body image as the main barriers to participation. The physical activity providers also discussed the influence of organisational, environmental and legislative factors. The findings from this project can inform interventions, research and policy to ensure Girls indeed Can

D-branes and the Noncommutative Torus

We show that in certain superstring compactifications, gauge theories on noncommutative tori will naturally appear as D-brane world-volume theories. This gives strong evidence that they are well-defined quantum theories. It also gives a physical derivation of the identification proposed by Connes, Douglas and Schwarz of Matrix theory compactification on the noncommutative torus with M theory compactification with constant background three-form tensor field.Comment: harvmac, 5 pp. Minor error fixe

Ultrasonic ranking of toughness of tungsten carbide

The feasibility of using ultrasonic attenuation measurements to rank tungsten carbide alloys according to their fracture toughness was demonstrated. Six samples of cobalt-cemented tungsten carbide (WC-Co) were examined. These varied in cobalt content from approximately 2 to 16 weight percent. The toughness generally increased with increasing cobalt content. Toughness was first determined by the Palmqvist and short rod fracture toughness tests. Subsequently, ultrasonic attenuation measurements were correlated with both these mechanical test methods. It is shown that there is a strong increase in ultrasonic attenuation corresponding to increased toughness of the WC-Co alloys. A correlation between attenuation and toughness exists for a wide range of ultrasonic frequencies. However, the best correlation for the WC-Co alloys occurs when the attenuation coefficient measured in the vicinity of 100 megahertz is compared with toughness as determined by the Palmqvist technique

Gauge Symmetry, T-Duality and Doubled Geometry

String compactifications with T-duality twists are revisited and the gauge algebra of the dimensionally reduced theories calculated. These reductions can be viewed as string theory on T-fold backgrounds, and can be formulated in a `doubled space' in which each circle is supplemented by a T-dual circle to construct a geometry which is a doubled torus bundle over a circle. We discuss a conjectured extension to include T-duality on the base circle, and propose the introduction of a dual base coordinate, to give a doubled space which is locally the group manifold of the gauge group. Special cases include those in which the doubled group is a Drinfel'd double. This gives a framework to discuss backgrounds that are not even locally geometric.Comment: 16 page

Stringy AdS3 from the Worldsheet

We investigate the behaviour of the bosonic string on AdS3 with H-flux at stringy scales, looking in particular for a `tensionless' limit in which there are massless higher spin gauge fields. We do this by revisiting the physical spectrum of the sl(2,R)$_k$ WZW model and considering the limit in which k becomes small. At k=3 we find that there is an infinite stringy tower of massless higher spin fields which are part of a continuum of light states. This can be viewed as a novel tensionless limit, which appears to be distinct from that inferred from the symmetric orbifold description of superstring AdS3 vacua.Comment: 13 page

Microstructural and strength stability of CVD SiC fibers in argon environment

The room temperature tensile strength and microstructure of three types of commercially available chemically vapor deposited silicon carbide fibers were measured after 1, 10, and 100 hour heat treatments under argon pressures of 0.1 to 310 MPa at temperatures to 2100 C. Two types of fiber had carbon-rich surface coatings and the other contained no coating. All three fiber types showed strength degradation beyond 1400 C. Time and temperature of exposure had greater influence on strength degradation than argon pressure. Recrystallization and growth of near stoichiometric SiC grains appears to be the dominant mechanism for the strength degradation

When corporate social responsibility matters: An empirical investigation of contingencies

Rather than re-examine the question of whether doing good generally helps a company to do well, this study draws on contingency theory to empirically examine when doing good helps a company do as well as possible. Using panel data, we examine the effects of industry life cycle, munificence, and instability on the relationship between corporate social responsibility (CSR) and corporate financial performance (CFP). Our findings indicate that life cycle has a significant impact on the CSR-CFP relationship, as does industry instability. These findings suggest that CSR helps the bottom line considerably – if it is applied at the right time