Estimation of fatigue strength of TiN coatings using cyclic micro-impact testing

This study delves into the behaviour of a thin TiN coating on a tool steel substrate material under dynamic and cyclic impacts through a comprehensive approach combining experimental testing and computational modelling. In dynamic impact tests, a pendulumbased setup investigates material responses under varying acceleration loads, revealing a distinctive "ringing effect" as the indenter bounces off the specimen's surface, with all plastic deformation concentrated during the initial impact. The study also quantifies dynamic hardness values, highlighting load-dependent behaviour and assessing the coating system's energy dissipation capabilities. In cyclic impact tests, materials experience permanent plastic deformation with each cycle, ultimately leading to coating failure. Chemical analysis identifies an interlayer between the coating and substrate, while cross-sectional analysis reveals the extent of coating damage due to cycling and load. A three-dimensional map is constructed, connecting acceleration load, sensed depth, and cycles to coating failure, and an empirical equation characterizes the relationship between depth and cycles before failure. The computational model scrutinizes traction component distribution during loading and unloading, with a focus on normal and shear tractions. The findings suggest the potential significance of normal traction in interface fatigue failure. Overall, offering implications for understanding and mitigating fatigue-related failures across various applications

Efficient Generation of Shape-Based Reference Frames for the Corpus Callosum for DTI-based Connectivity Analysis

Yushkevich et.al. [17, 18] established a PDE-based deformable modeling approach called continuous medial representation (cm-rep), in which the geometric relationship between the medial axis of a 3D object and its boundary is captured. Continuous medial description of an object not only provides useful shape features for object characterization and comparison; it also imposes a shape-based reference frame on the interior of that object. Such a reference frame provides a useful means of representing different instances of an anatomical structure using a common canonical parametrization domain. This paper presents an efficient method to construct continuous medial shape models for 2D objects. A closed form solution for the ordinary differential equation (ODE) is derived via Pythagorean hodograph (PH) curves. That closed form solution reduces the computation complexity from solving an ODE system to pure algebraic manipulation. Using this method, we generate shape-based reference frames, and demonstrate how they can be applied to the analysis of anatomical connectivity of corpora callosa, obtained by fiber tracking in diffusion tensor magnetic resonance imaging (DTI) in a chromosome 22q11.2 deletion syndrome study

Atypical cortical connectivity and visuospatial cognitive impairments are related in children with chromosome 22q11.2 deletion syndrome

BackgroundChromosome 22q11.2 deletion syndrome is one of the most common genetic causes of cognitive impairment and developmental disability yet little is known about the neural bases of those challenges. Here we expand upon our previous neurocognitive studies by specifically investigating the hypothesis that changes in neural connectivity relate to cognitive impairment in children with the disorder.MethodsWhole brain analyses of multiple measures computed from diffusion tensor image data acquired from the brains of children with the disorder and typically developing controls. We also correlated diffusion tensor data with performance on a visuospatial cognitive task that taps spatial attention.ResultsAnalyses revealed four common clusters, in the parietal and frontal lobes, that showed complementary patterns of connectivity in children with the deletion and typical controls. We interpreted these results as indicating differences in connective complexity to adjoining cortical regions that are critical to the cognitive functions in which affected children show impairments. Strong, and similarly opposing patterns of correlations between diffusion values in those clusters and spatial attention performance measures considerably strengthened that interpretation.ConclusionOur results suggest that atypical development of connective patterns in the brains of children with chromosome 22q11.2 deletion syndrome indicate a neuropathology that is related to the visuospatial cognitive impairments that are commonly found in affected individuals

EANM guideline for harmonisation on molar activity or specific activity of radiopharmaceuticals:impact on safety and imaging quality

Abstract This guideline on molar activity (Am) and specific activity (As) focusses on small molecules, peptides and macromolecules radiolabelled for diagnostic and therapeutic applications. In this guideline we describe the definition of Am and As, and how these measurements must be standardised and harmonised. Selected examples highlighting the importance of Am and As in imaging studies of saturable binding sites will be given, and the necessity of using appropriate materials and equipment will be discussed. Furthermore, common Am pitfalls and remedies are described. Finally, some aspects of Am in relation the emergence of a new generation of highly sensitive PET scanners will be discussed

Guided wave optics in periodically poled KTP: quadratic nonlinearity and prospects for attosecond jitter characterization

For the first time to our knowledge, continuous nonsegmented channel waveguides in periodically poled KTiOPO4 with guided orthogonal polarizations are used to demonstrate type II background-free second harmonic generation in the telecom band with 1.6%/(W cm2) normalized conversion efficiency. This constitutes a 90-fold improvement in aggregate conversion efficiency over its free space counterpart. Simulations show that the guided wave device should enable the measurement of timing fluctuations of optical pulse trains at the attosecond level in an optical cross correlation scheme

C5 Palsy After Cervical Spine Surgery: A Multicenter Retrospective Review of 59 Cases.

STUDY DESIGN: A multicenter, retrospective review of C5 palsy after cervical spine surgery. OBJECTIVE: Postoperative C5 palsy is a known complication of cervical decompressive spinal surgery. The goal of this study was to review the incidence, patient characteristics, and outcome of C5 palsy in patients undergoing cervical spine surgery. METHODS: We conducted a multicenter, retrospective review of 13 946 patients across 21 centers who received cervical spine surgery (levels C2 to C7) between January 1, 2005, and December 31, 2011, inclusive. P values were calculated using 2-sample t test for continuous variables and χ(2) tests or Fisher exact tests for categorical variables. RESULTS: Of the 13 946 cases reviewed, 59 patients experienced a postoperative C5 palsy. The incidence rate across the 21 sites ranged from 0% to 2.5%. At most recent follow-up, 32 patients reported complete resolution of symptoms (54.2%), 15 had symptoms resolve with residual effects (25.4%), 10 patients did not recover (17.0%), and 2 were lost to follow-up (3.4%). CONCLUSION: C5 palsy occurred in all surgical approaches and across a variety of diagnoses. The majority of patients had full recovery or recovery with residual effects. This study represents the largest series of North American patients reviewed to date

Framing interculturality: a corpus-based analysis of on-line promotional discourse of higher education intercultural communication courses

This paper examines how intercultural communication (ICC) and the notion of culture are framed in on-line promotional discourse of higher education intercultural communication courses. It analyses a specialised corpus comprised of 14,842 words from 43 course websites of master’s programmes in intercultural communication in the UK and the US—internationally, the two largest providers of such programmes. Through combining corpus tools with a ‘situated meaning’ approach, the analysis reveals that while a small number of courses acknowledge cultural ‘complexity’, culture is still very often reduced to an essentialised and static notion, despite growing criticism against such an approach in ICC literature. Intercultural communication is valorised as a combination of desirable skills and knowledge conducive to effective communication of different cultural groups and for those working in international arenas. Significant differences between the UK and US courses are identified with regard to the extent of associations with diversity-related social categories. The lack of interpretive, critical and constructivist positions on culture in promotional discourse is discussed in the context of neoliberal discourse and the current thinking towards professional competences dominant in Britain, North America, and other parts of the world

The structural properties of sexual fantasies for sexual offenders : a preliminary model

While the phenomenon of sexual fantasy has been researched extensively, little contemporary inquiry has investigated the structural properties of sexual fantasy within the context of sexual offending. In this study, a qualitative analysis was used to develop a descriptive model of the phenomena of sexual fantasy during the offence process. Twenty-four adult males convicted of sexual offences provided detailed retrospective descriptions of their thoughts, emotions and behaviours—before, during and after their offences. A data-driven approach to model development, known as Grounded Theory, was undertaken to analyse the interview transcripts. A model was developed to elucidate the structural properties of sexual fantasy in the process of sexual offending, as well as the physiological and psychological variables associated with it. The Sexual Fantasy Structural Properties Model (SFSPM) comprises eight categories that describe various properties of sexual fantasy across the offence process. These categories are: origin, context, trigger, perceptual modality, clarity, motion, intensity and emotion. The strengths of the SFSPM are discussed and its clinical implications are reviewed. Finally, the limitations of the study are presented and future research directions discussed

The Iceland Microcontinent and a continental Greenland-Iceland-Faroe Ridge

The breakup of Laurasia to form the Northeast Atlantic Realm was the culmination of a long period of tectonic unrest extending back to the Late Palaeozoic. Breakup was prolonged and complex and disintegrated an inhomogeneous collage of cratons sutured by cross-cutting orogens. Volcanic rifted margins formed, which are blanketed by lavas and underlain variously by magma-inflated, extended continental crust and mafic high-velocity lower crust of ambiguous and probably partly continental provenance. New rifts formed by diachronous propagation along old zones of weakness. North of the Greenland-Iceland-Faroe Ridge the newly forming rift propagated south along the Caledonian suture. South of the Greenland-Iceland-Faroe Ridge it propagated north through the North Atlantic Craton along an axis displaced ~ 150 km to the west of the northern rift. Both propagators stalled where the confluence of the Nagssugtoqidian and Caledonian orogens formed a transverse barrier. Thereafter, the ~ 400-km-wide latitudinal zone between the stalled rift tips extended in a distributed, unstable manner along multiple axes of extension that frequently migrated or jumped laterally with shearing occurring between them in diffuse transfer zones. This style of deformation continues to the present day. It is the surface expression of underlying magma-assisted stretching of ductile mid- and lower continental crust which comprises the Icelandic-type lower crust that underlies the Greenland-Iceland-Faroe Ridge. This, and probably also one or more full-crustal-thickness microcontinents incorporated in the Ridge, are capped by surface lavas. The Greenland-Iceland-Faroe Ridge thus has a similar structure to some zones of seaward-dipping reflectors. The contemporaneous melt layer corresponds to the 3–10 km thick Icelandic-type upper crust plus magma emplaced in the ~ 10–30-km-thick Icelandic-type lower crust. This model can account for seismic and gravity data that are inconsistent with a gabbroic composition for Icelandic-type lower crust, and petrological data that show no reasonable temperature or source composition could generate the full ~ 40-km thickness of Icelandic-type crust observed. Numerical modeling confirms that extension of the continental crust can continue for many tens of Myr by lower-crustal flow from beneath the adjacent continents. Petrological estimates of the maximum potential temperature of the source of Icelandic lavas are up to 1450 °C, no more than ~ 100 °C hotter than MORB source. The geochemistry is compatible with a source comprising hydrous peridotite/pyroxenite with a component of continental mid- and lower crust. The fusible petrology, high source volatile contents, and frequent formation of new rifts can account for the true ~ 15–20 km melt thickness at the moderate temperatures observed. A continuous swathe of magma-inflated continental material beneath the 1200-km-wide Greenland-Iceland-Faroe Ridge implies that full continental breakup has not yet occurred at this latitude. Ongoing tectonic instability on the Ridge is manifest in long-term tectonic disequilibrium on the adjacent rifted margins and on the Reykjanes Ridge, where southerly migrating propagators that initiate at Iceland are associated with diachronous swathes of unusually thick oceanic crust. Magmatic volumes in the NE Atlantic Realm have likely been overestimated and the concept of a monogenetic North Atlantic Igneous Province needs to be reappraised. A model of complex, piecemeal breakup controlled by pre-existing structures that produces anomalous volcanism at barriers to rift propagation and distributes continental material in the growing oceans fits other oceanic regions including the Davis Strait and the South Atlantic and West Indian oceans

Application of computer-aided tomography techniques to visualize kelp holdfast structure reveals the importance of habitat complexity for supporting marine biodiversity

Ecosystem engineers that increase habitat complexity are keystone species in marine systems, increasing shelter and niche availability, and therefore biodiversity. For example, kelp holdfasts form intricate structures and host the largest number of organisms in kelp ecosystems. However, methods that quantify 3D habitat complexity have only seldom been used in marine habitats, and never in kelp holdfast communities. This study investigated the role of kelp holdfasts (Laminaria hyperborea) in supporting benthic faunal biodiversity. Computer-aided tomography (CT-) scanning was used to quantify the three-dimensional geometrical complexity of holdfasts, including volume, surface area and surface fractal dimension (FD). Additionally, the number of haptera, number of haptera per unit of volume, and age of kelps were estimated. These measurements were compared to faunal biodiversity and community structure, using partial least-squares regression and multivariate ordination. Holdfast volume explained most of the variance observed in biodiversity indices, however all other complexity measures also strongly contributed to the variance observed. Multivariate ordinations further revealed that surface area and haptera per unit of volume accounted for the patterns observed in faunal community structure. Using 3D image analysis, this study makes a strong contribution to elucidate quantitative mechanisms underlying the observed relationship between biodiversity and habitat complexity. Furthermore, the potential of CT-scanning as an ecological tool is demonstrated, and a methodology for its use in future similar studies is established. Such spatially resolved imager analysis could help identify structurally complex areas as biodiversity hotspots, and may support the prioritization of areas for conservation