Efficient three dimensional modelling of additive manufactured textiles

Purpose – To investigate, develop and validate a three dimensional modelling strategy for the efficient generation of conformal textile data suitable for Additive Manufacture. Design/methodology/approach – A series of Additive Manufactured textiles samples were modelled using currently available Computer Aided Design software to understand the limitations associated with the generation of conformal data. Results of the initial three dimensional modelling processes informed the exploration and development of a new dedicated efficient modelling strategy that was tested to understand its capabilities. Findings – The research demonstrates the dramatically improved capabilities of the developed three dimensional modelling strategy, over existing approaches by accurately mapping complex geometries described as STL data to a mapping mesh without distortion and correctly matching the orientation and surface normal. Originality/value – To date the generation of data for AM textiles has been seen as a manual and time-consuming process. The research presents a new dedicated methodology for the efficient generation of complex and conformal Additive Manufactured textile data that will underpin further research in this area

Interpreting experimental bounds on D^0 - \bar{D^0} mixing in the presence of CP violation

We analyse the most recent experimental data regarding D^0 - \bar{D^0} mixing, allowing for CP violation. We focus on the dispersive part of the mixing amplitude, M^D_{12}, which is sensitive to new physics contributions. We obtain a constraint on the mixing amplitude: |M^D_{12}| < 6.2\times 10^{-11} MeV at 95% C.L. . This constraint is weaker by a factor of about three than the one which is obtained when no CP violation is assumed.Comment: 9 pages, revtex4; One reference updated, one reference added, footnote 3 correcte

Ondes scélérates et autres manifestations extrêmes dans les fibres optiques

National audienceNous présentons divers exemples d'évènements rares optiques qui peuvent apparaître lors de la propagation d'impulsions dans des fibres optiques. Ainsi, différents types de structures optiques se démarquant très nettement du comportement statistique moyen ont été mis en évidence dans les processus de génération de supercontinua optiques ainsi que dans les phases d'amplification paramétrique ou Raman

Preformation of clusters in heavy nuclei and cluster radioactivity

Within the preformed cluster model approach, the values of the preformation factors have been deduced from the experimental cluster decay half-lives assuming that the decay constant of the heavy-ion emission is the product of the assault frequency, the preformation factor and the penetrability. The law according to which the preformation factors follow a simple dependence on the mass of the cluster was confirmed. Then predictions for some most possible cluster decays are provided

Epidemiology and impact of chronic bronchitis in chronic obstructive pulmonary disease

Research on the association between chronic bronchitis and chronic obstructive pulmonary disease (COPD) exacerbations has led to discordant results. Furthermore, the impact of chronic bronchitis on mortality in COPD subjects is unclear. Within the Rotterdam Study, a population-based cohort study of subjects aged ≥45 years, chronic bronchitis was defined as having a productive cough for ≥3 months per year for two consecutive years. Linear, logistic regression and Cox proportional hazard models were adjusted for age, sex and pack-years. Out of 972 included COPD subjects, 752 had no chronic phlegm production (CB-) and 220 had chronic phlegm production, of whom 172 met the definition of chronic bronchitis (CB+). CB+ subjects were older, more frequently current smokers and had more pack-years than CB- subjects. During a median 6.5 years of followup, CB+ subjects had greater decline in lung function (-38 mL·year-1, 95% CI -61.7 - -14.6; p=0.024). CB+ subjects had an increased risk of frequent exacerbations (OR 4.0, 95% CI 2.7-5.9; p<0.001). In females, survival was significantly worse in CB+ subjects compared to CB- subjects. Regarding cause-specific mortality, CB+ subjects had an increased risk of respiratory mortality (hazard ratio 2.16, 95% CI 1.12-4.17; p=0.002). COPD subjects with chronic bronchitis have an increased risk of exacerbations and respiratory mortality compared to COPD subjects without chronic phlegm production

Analytic expressions for alpha particle preformation in heavy nuclei

The experimental alpha decay energies and half-lives are investigated systematically to extract the alpha particle preformation in heavy nuclei. Formulas for the preformation factors are proposed. They can be used to guide the microscopic studies on preformation factors and perform accurate calculations of the alpha decay half-lives. There is little evidence for the existence of an island of long stability of superheavy nuclei (SHN)

Finite-element modelling of mechanical behaviour of rapid manufactured textiles

Novel textile-like linked structures, realised using a rapid manufacturing (RM) process, have been proposed and developed recently. Various potential applications exist, and in most cases the mechanical performance must be evaluated. The present paper outlines a method to solve this problem by employing finite-element (FE) techniques at two scales, using the results of analysis at the meso-scale (the scale of the repeating unit) to provide equivalent non-linear spring behaviour for each textile link at the macro-scale. Validation with experimental test data from each scale was performed and these results are presented. Initial results overestimated mechanical performance. Microscopy suggested that this may be due to edge porosity in the specimens, and the dimensions of the FE models were adjusted accordingly as an initial approach to account for this. Predictions incorporating this modification exhibited excellent agreement with experimental measurements. The current work demonstrates both a technique, which could be automated for use in the design environment, and the potential value of developing an integrated process simulation to provide local material property data for the FE model

Specialist or Nonspecialist Physical Education Teachers in Ontario Elementary Schools: Examining Differences in Opportunities for Physical Activity

Research supports the position that specialists are the preferred providers of physical education in elementary (primary) school settings. We examined whether specialists delivered more physical education lessons and provided greater opportunities for moderate and vigorous physical activity and whether barriers to curricular and extracurricular physical activity opportunities in Ontario elementary schools differed for specialist and nonspecialist teachers. Using a cross-sectional design, a questionnaire was mailed to key informants in 599 randomly selected elementary schools in Ontario, yielding an 85% response rate. Most physical education in Ontario elementary schools is delivered by nonspecialists (63%). No self-reported differences were found between specialists and generalist teachers in the number of physical education lessons delivered per week, the minutes per physical education class, or in the amount of reported moderate or vigorous physical activity in lessons. Compared with specialists, respondents in schools in which generalist teachers taught PE perceived lack of training as a greater barrier to delivering physical education. Given the importance of subject knowledge in teaching effectively, there is still need to advocate for specialist physical education teaching in elementary schools. However, concerns about teaching specialism may be secondary to broader and more complex factors surrounding the delivery of physical education in elementary schools.La recherche appuie le point de vue selon lequel les spécialistes sont les mieux placés pour enseigner l’éducation physique au primaire. Nous nous sommes penchés sur deux questions: (a) les spécialistes offrent-ils plus de cours d’éducation physique et d’occasions de pratiquer des activités physiques modérées ou vigoureuses ?, et (b) les obstacles à la participation aux activités physiques scolaires et extra-scolaires dans les écoles primaires de l’Ontario sont-ils les mêmes pour les enseignants spécialistes et les enseignants non-spécialistes ? Dans le contexte d’un modèle croisé, nous avons envoyé un questionnaire à des répondants clés dans 599 écoles primaires sélectionnées au hasard en Ontario. Notre taux de réponse a été de 85%. La majorité (63%) des cours d’éducation physique en Ontario sont offerts par des non spécialistes. Les résultats n’indiquent aucune différence entre les enseignants spécialistes et les enseignants non-spécialistes quant aux critères suivants: le nombre de cours d’éducation physique offerts par semaine, la durée des cours d’éducation physique et la mesure dans laquelle les cours impliquent de l’activité physique modérée ou vigoureuse. Par rapport aux répondants des écoles où les cours d’éducation physique se donnaient par des spécialistes, ceux des écoles où ces cours se donnaient par des généralistes ont indiqué que le manque de formation constituait un obstacle plus important à l’enseignement de l’éducation physique. Compte tenu du rôle important de la connaissance de la matière dans l’enseignement efficace, il faudrait continuer à promouvoir l’enseignement de l’éducation physique par des spécialistes dans les écoles primaires. Toutefois, les préoccupations portant sur l’enseignement par des spécialistes semblent secondaires face aux facteurs plus généraux et complexes en matière d’enseignement de l’éducation physique dans les écoles primaires

Hard Instances of the Constrained Discrete Logarithm Problem

The discrete logarithm problem (DLP) generalizes to the constrained DLP, where the secret exponent $x$ belongs to a set known to the attacker. The complexity of generic algorithms for solving the constrained DLP depends on the choice of the set. Motivated by cryptographic applications, we study sets with succinct representation for which the constrained DLP is hard. We draw on earlier results due to Erd\"os et al. and Schnorr, develop geometric tools such as generalized Menelaus' theorem for proving lower bounds on the complexity of the constrained DLP, and construct sets with succinct representation with provable non-trivial lower bounds