Fretting wear of Ti(CxNy) PVD coatings under variable environmental conditions

Fretting wear as a specific type of degradation is defined as an oscillatory motion at small amplitude between two nominally stationary solid bodies in mutual contact. Under external stresses the interface is being damaged by debris generation and its successive ejections outside the contact area. A potential protection against fretting damage by means of hard coatings is being offered by different surface engineering techniques. For this study TiC, TiN and TiCN hard coatings manufactured by a PVD method have been selected and tested against smooth polycrystalline alumina ball. A fretting test programme has been carried out at the frequency of 5Hz, 100N normal load, 100µm displacement amplitude and at three values of a relative humidity: 10, 50 and 90% at 295-298K temperature. It turned out that the intensity of wear process was depending not only on loading conditions but on environmental ones as well. A significant impact of RH on wear rate and friction behaviour of the coatings under investigation has been observed. Two different damage mechanisms have been identified and related to the phenomena of debris oxidation and debris adhesion to the counterbody surface. In the latter case the debris deposited onto the surface of the alumina ball lead to a change of stress distribution at the interface and as a result to accelerated wear. In this work experiments with variable relative humidity increasing from 10% to 90% within 1 a single fretting test have been completed. It follows from these experiments that there exists an intermediate value of the RH at which the friction coefficient changes rapidly. Finally a dissipated energy approach has been applied in the work in order to quantify and compare fretting wear rates of different hard coatings

Historical Criminology and the Explanatory Power of the Past

To what extent can the past ‘explain’ the present? This deceptively simple question lies at the heart of historical criminology (research which incorporates historical primary sources while addressing present-day debates and practices in the criminal justice field). This article seeks first to categorise the ways in which criminologists have used historical data thus far, arguing that it is most commonly deployed to ‘problematize’ the contemporary rather than to ‘explain’ it. The article then interrogates the reticence of criminologists to attribute explicative power in relation to the present to historical data. Finally, it proposes the adoption of long time-frame historical research methods, outlining three advantages which would accrue from this: the identification and analysis of historical continuities; a more nuanced, shared understanding of micro/macro change over time in relation to criminal justice; and a method for identifying and analysing instances of historical recurrence, particularly in perceptions and discourses around crime and justice

Testing the Noncommutative Standard Model at a Future Photon Collider

Extensions of the Standard Model of elementary particle physics to noncommutative geometries have been proposed as a low energy limit of string models. Independent of this motivation, one may consider such a model as an effective field theory with higher-dimensional operators containing an antisymmetric rank-two background field. We study the signals of such a Noncommutative Standard Model (NCSM) and analyze the discovery potential of a future photon collider, considering angular distributions in fermion pair production.Comment: 13 pages RevTeX, Feynman diagrams and figures included, references added, typographical errors in Feynman rules corrected (all results remain unchangend, since correct Feynman rules were used in the calculations), to appear in Phys. Rev.

Relativistic quantum plasma dispersion functions

Relativistic quantum plasma dispersion functions are defined and the longitudinal and transverse response functions for an electron (plus positron) gas are written in terms of them. The dispersion is separated into Landau-damping, pair-creation and dissipationless regimes. Explicit forms are given for the RQPDFs in the cases of a completely degenerate distribution and a nondegenerate thermal (J\"uttner) distribution. Particular emphasis is placed on the relation between dissipation and dispersion, with the dissipation treated in terms of the imaginary parts of RQPDFs. Comparing the dissipation calculated in this way with the existing treatments leads to the identification of errors in the literature, which we correct. We also comment on a controversy as to whether the dispersion curves in a superdense plasma pass through the region where pair creation is allowed.Comment: 16 pages, 1 figur

The Relationship of Eccentric Hamstrings Time to Peak Torque and Anterior Knee Joint Displacement

Research suggests that females are more likely to sustain an anterior cruciate ligament (ACL) injury when compared to males and that the ACL and hamstring muscles work together to preserve joint stability. Information is limited regarding any relationship between anterior knee joint laxity, in the absence of injury, and eccentric hamstring time to peak torque. This study compared anterior knee joint displacement and eccentric hamstrings time to peak torque in 30 female athletes and 30 female non-athletes ages 14-18 years. The passive anterior drawer was measured on both lower extremities using the KT-1000® arthrometer before and after eccentric hamstrings time to peak torque testing on the Biodex® System 2 isokinetic dynamometer. Data were collected at two speeds, 90°/second and 150°/second. Results of this study suggest there is no relationship between eccentric hamstrings time to peak torque and anterior knee joint displacement in the two populations tested

The evolution and development of visual perspective taking

I outline three conceptions of seeing that a creature might possess: ‘the headlamp conception,’ which involves an understanding of the causal connections between gazing at an object, certain mental states, and behavior; ‘the stage lights conception,’ which involves an understanding of the selective nature of visual attention; and seeing-as. I argue that infants and various nonhumans possess the headlamp conception. There is also evidence that chimpanzees and 3-year-old children have some grasp of seeing-as. However, due to a dearth of studies, there is no evidence that infants or nonhumans possess the stage lights conception of seeing. I outline the kinds of experiments that are needed, and what we stand to learn about the evolution and development of perspective taking

Soft methods, hard targets: regional alcohol managers as a policy network

Regional Alcohol Managers (RAMs) was employed in the nine English health regions over 2008–2011. Their mission was to impact on the ‘hard target’ of Alcohol-Related Hospital Admissions (AHRAs) through the ‘soft methods’ of persuasion and influence: working with local partners on evidence-based interventions. Drawing on a qualitative evaluation, this article shows how a central government policy imperative (ARHAs) led to ‘government at a distance’ responses, including the introduction of RAMs. The processes involved in shaping and delivering this function bore the hallmarks of a complex, interactive policy network model, involving individuals whose bearings and roles were flexible and sometimes ambiguous. While there were overlaps and blurring of boundaries, there were three levels of policy network: central government, regional and local. As the ‘network in the middle’, the RAMs were pulled in both directions by conflicting agendas but were also able to have an impact on central and local policy

Perceptions on the role of evidence: an English alcohol policy case study

This paper explores the competing influences which inform public health policy and describes the role that research evidence plays within the policy-making process. In particular it draws on a recent English alcohol policy case study to assess the role of evidence in informing policy and practice. Semi-structured interviews with key national, regional and local policy informants were transcribed and analysed thematically. A strong theme identified was that of the role of evidence. Findings are discussed in the context of competing views on what constitutes appropriate evidence for policy-making

The alcohol improvement programme: evaluation of an initiative to address alcohol-related health harm in England

Aims: The evaluation aimed to assess the impact of The Alcohol Improvement Programme (AIP). This was a UK Department of Health initiative (April 2008–March 2011) aiming to contribute to the reduction of alcohol-related harm as measured by a reduction in the rate of increase in alcohol-related hospital admissions (ARHAs). Methods: The evaluation (March 2010–September 2011) used a mix of qualitative and quantitative methods to assess the impact of the AIP on ARHAs, to describe and assess the process of implementation, and to identify elements of the programme which might serve as a ‘legacy’ for the future. Results: There was no evidence that the AIP had an impact on reducing the rise in the rate of ARHAs. The AIP was successfully delivered, increased the priority given to alcohol-related harm on local policy agendas and strengthened the infrastructure for the delivery of interventions. Conclusion: Although there was no measurable short-term impact on the rise in the rate of ARHAs, the AIP helped to set up a strategic response and a delivery infrastructure as a first, necessary step in working towards that goal. There are a number of valuable elements in the AIP which should be retained and repackaged to fit into new policy contexts