Non-destructive inspection of polymer sample using a periodically moving heating source

Introduction The development of innovative materials with specific properties requires the design of non-destructive testing methods. The proposed study is focused on the localization of a possible defect in a polymer sample. In such an aim, a frequency analysis based on a periodic heating can reveal the defect location (see authors previous works). However this approach is usually time-consuming and this feature could reduce the method attractiveness in an industrial context. In the proposed communication, a new protocol has been developed in order to reduce the inspection duration. Methods Let us consider that the material to be studied is a polymer plate. On the upper face of this plate, a radiative heater is considered. Its power supply is kept constant. Its spatial distribution is limited to a disc of small radius r. Moreover, this source moves circularly so as to heat the plate. Once the steady state established, the temperature at each point of the sample is periodic. The frequency of the oscillations is related to the angular velocity of the source. Two observable characteristics of these "thermal waves" can then be taken into account at each point of the surface: the modulus and the phase shift of the thermograms. It has been shown that modulus is more relevant for defect location. Results and Discussion An example of thermograms is shown on figure I. The contrast distribution (difference of two cartographies of modulus with and without defect) is presented on figure II. Considering this numerical example, the whole plate inspection is performed and methods feasibility is exposed. Several concrete results based on our experimental device will be exposed during the conference

Justifications-on-demand as a device to promote shifts of attention associated with relational thinking in elementary arithmetic

Student responses to arithmetical questions that can be solved by using arithmetical structure can serve to reveal the extent and nature of relational, as opposed to computational thinking. Here, student responses to probes which require them to justify-on-demand are analysed using a conceptual framework which highlights distinctions between different forms of attention. We analyse a number of actions observed in students in terms of forms of attention and shifts between them: in the short-term (in the moment), medium-term (over several tasks), and long-term (over a year). The main factors conditioning students´ attention and its movement are identified and some didactical consequences are proposed

Dietary assessment of British police force employees: A description of diet record coding procedures and cross-sectional evaluation of dietary energy intake reporting (The Airwave Health Monitoring Study)

Objectives: Dietary intake is a key aspect of occupational health. To capture the characteristics of dietary behaviour that is affected by occupational environment that may affect disease risk, a collection of prospective multiday dietary records is required. The aims of this paper are to: (1) collect multiday dietary data in the Airwave Health Monitoring Study, (2) describe the di etary coding procedures applied and (3) investigate the plausibility of dietary reporting in this occupational cohort. Design: A dietary coding protocol for this large-scale study was developed to minimise coding error rate. Participants (n 4412) who completed 7-day food records were included for cross-sectional analyses. Energy intake (EI) misreporting was estimated using the Goldberg method. Multivariate logistic regression models were applied to determine participant characteristics associated with EI misreporting. Setting: British police force employees enrolled (2007-2012) into the Airwave Health Monitoring Study. Results: The mean code error rate per food diary was 3.7% (SD 3.2%). The strongest predictors of EI under-reporting were body mass index (BMI) and physical activity. Compared with participants with BMI 30 kg/m2 had increased odds of being classified as under-reporting EI (men OR 5.20 95% CI 3.92 to 6.89; women OR 2.66 95% CI 1.85 to 3.83). Men and women in the highest physical activity category compared with the lowest were also more likely to be classified as underreporting (men OR 3.33 95% CI 2.46 to 4.50; women OR 4.34 95% CI 2.91 to 6.55). Conclusions: A reproducible dietary record coding procedure has been developed to minimise coding error in complex 7-day diet diaries. The prevalence of EI under-reporting is comparable with existing national UK cohorts and, in agreement with previous studies, classification of under-reporting was biased towards specific subgroups of participants

Натечные карбонатные новообразования набережной реки Туры: особенности строения и процессы формирования

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Probing the Impact of Porosity on Swelling Kinetics of Hydrophilic Matrices

The aim of the present investigation was to understand the swelling behaviour of HPMC and PEO-based matrices and to evaluate the impact of porosity on the swelling kinetics. It was noticed that the HPMC has higher swelling rates but both undergo diffusion oriented swelling mechanism. It could also the concluded that the porosity has a marked influence in the development of gel layer on the surface of these matrices