Study of Post-World War II French Aeronautical Aluminium Alloy and Coatings: Historical and Materials Science Approach     

Magali Brunet  Audrey Cochard  Christophe Deshayes  Chantal Brouca-Cabarrecq  Luc Robbiola  Jean-Marc Olivier 《文物保护研究》2020,65(2):103-117

ABSTRACT

In many countries, collections of historic aircraft, conserved in Air and Space museums or local associations, reflect the importance of a national or local history. Mostly parked outdoors, aircraft suffer from significant corrosion requiring conservation operations. During renovation, metallic parts are often replaced by association members. This can lead to a major loss of information since industrial archives dealing with materials and processes do not always survive. However, if these elements can be considered, they could be a fundamental source of information on the materials originally used and of the technical history of aeronautics. This work reports a thorough study of aluminium-based alloy parts collected on a Breguet aeroplane dating from the 1950s, during its recent renovation. Thanks to an approach coupling multi-scale material characterisation and research in archives, information on the industrial knowledge is revealed. Several historic grades of aluminium-based alloys were found, namely A-U4G, A-U4G1, and A-U3G, depending on the role of the part. Similarly, different protective coatings were identified (anodic oxidation, primers, and paintings), depending on the role of the metallic part and its location in the plane. Knowledge of the materials from bulk metal to the coated surface is necessary for good conservation practices regarding aeronautical heritage artefacts. Related documents and archives also fundamentally help in understanding such complex artefacts.  相似文献   

Complementing subjective with objective data in analysing expertise: A machine-learning approach applied to badminton     

Olivier Dieu  Christophe Schnitzler  Clément Llena  François Potdevin 《Journal of sports sciences》2020,38(17):1943-1952

ABSTRACT

This study aimed to assess which combination of subjective and empirical data might help to identify the expertise level. A group of 10 expert coaches classified 40 participants in 5 different expertise groups based on the video footage of the rallies. The expertise levels were determined using a typology based on a continuum of 5 conative stages: (1) structural, (2) functional, (3) technical, (4) contextual, and (5) expertise. The video allowed empirical measurement of the duration of the rallies, and tri-axial accelerometers measured the intensity of the player’s involvement. A principal component analysis showed that two dimensions explained 54.9% of the total variance in the data and that conative stage and empirical parameters during rallies (duration, intensity of the game) were correlated with axis 1, whereas duration and acceleration data between rallies were correlated with axis 2. A random forest algorithm showed that among the parameters considered, acceleration, duration of the rallies, and time between rallies could predict conative stages with a prediction accuracy above possibility.

This study suggests that performance analysis benefits from the confrontation of subjective and objective data in order to design training plans according to the expertise level of the participants.  相似文献   

Instructional principles for self-regulation     

Kathryn Ley  Dawn B. Young 《Educational technology research and development : ETR & D》2001,49(2):93-103

The purpose of this article is to suggest principles for embedding support in instruction to facilitate self-regulation (SR) in less expert learners. The principles are based on an analysis of the growing body of research on the distinctive self-regulation differences between higher and lower achieving learners. The analysis revealed four instructional principles that designers should consider to provide support for self-regulation. Each principle is supported by research and instructional examples are included.  相似文献   

The Cartographic Eye in Children’s Picturebooks: Between Maps and Narratives     

Christophe Meunier 《Children‘s Literature in Education》2017,48(1):21-38

This article examines the place occupied by maps in children’s picturebooks. After a brief overview of the different roles that are assigned to maps in children’s books, the article considers five French picturebooks—Warja Lavater’s Le petit chaperon rouge (1965), Olivier Douzou and Isabelle Simon’s L’autobus numéro 33 (1996), Véronique Vernette’s Cocorico poulet Piga (1999), Rebecca Dautremer and Arthur Leboeuf’s Le loup de la 135 ^ème (2008) and Kochka and Fabienne Cinquin’s Dans ma ville, il y a… (2011)—in order to focus on how the narrative, whether enclosed, superimposed or linked to the text in some other way, is evoked by the geographic shape of the maps. It is argued that the particular use and function of a map depends on its shape or placement in a book, distinguishing between the incorporation of maps only as a significant picture (its use) from the subject within the whole narrative (its function). Thus the article articulates what uses a map can have within a narrative. It also explores the mechanics of the iconotext, showing that a cartographic picture fulfils a precise, rather than a general, function of spatialisation. Hence three main functions of spatialisation in maps and mapping are distinguished, whereby an author could use maps to help a character discover, conquer, or organise a space.  相似文献   

Beating the bounds: The Tour de France and national identity     

Christophe Campos 《国际体育史杂志》2013,30(2):149-174

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Europalia.China Concludes with Great Success     

Christophe Pourtois  Marcelle Rabinowicz 《中外文化交流(英文版)》2010,(4):4-9

<正>Europalia is a major international arts festival held every other year to celebrate one invited country's cultural heritage. Founded in 1969, this biennial festival is celebrated in  相似文献   

Shoe drop reduction influences the lower limb biomechanics of children tennis players during an open stance forehand: A longitudinal study     

Alexis Herbaut  Emilie Simoneau-Buessinger  Franck Barbier  Christophe Gillet  Maxime Roux  Nils Guéguen 《European Journal of Sport Science》2017,17(10):1261-1269

Compared to traditional tennis shoes, using 0-drop shoes was shown to induce an immediate switch from rear- to forefoot strike pattern to perform an open stance tennis forehand for 30% of children tennis players. The purpose of the study was to examine the long-term effects of a gradual reduction in the shoe drop on the biomechanics of children tennis players performing open stance forehands. Thirty children tennis players participated in 2 laboratory biomechanical test sessions (intermediate: +4 months and final: +8 months) after an inclusion visit where they were randomly assigned to control (CON) or experimental (EXP) group. CON received 12-mm-drop shoes twice, whereas EXP received 8?mm then 4-mm-drop shoes. Strike index indicated that all CON were rearfoot strikers in intermediate and final test sessions. All EXP were rearfoot strikers in intermediate test session, but half the group switched towards a forefoot strike pattern in final test session. This switch resulted in a decreased loading rate of the ground reaction force (?73%, p?=?.005) but increased peak ankle plantarflexors moment (+47%, p?=?.050) and peak ankle power absorption (+107%, p?=?.005) for these participants compared with CON. Biomechanical changes associated with the long-term use of partial minimalist shoes suggest a reduction in heel compressive forces but an increase in Achilles tendon tensile forces.  相似文献   

Hydrodynamics and oxygen transfer in a novel extra-loop fluidized bed bioreactor     

陆永生  胡龙兴 《上海大学学报(英文版)》2010,14(4):266-274

In this paper, the characteristics of fluid mixing time in a novel extra-loop fluidized bed were studied. The results showed that the mixing time was shortened with the increase of fluid velocity. All the discrete numbers of the reactor were above 0.2. The serial number n was 2.5 -3.0. It was judged accordingly that the reactor fluid state was continous stirred tank reactor （CSTR） mainly. When the inspiratory capacity increased the mixing time of the reactor was shortened. Thus the air input was beneficial for the fluid mixing. During the three phases mixing process, the mixing time of the reactor could be decreased by the n increase of carrier and air loading together, but the change was not significant. The parameters affecting the reactor fluid state were fluid velocity, inspiratory capacity and carrier. KLa could be increased with the air loading increase, and at the same gas/liquid ratio when the pressure drop was high, KL~ value was increased. The amount of carrier complex influence on KLa. As the carrier loading continued to increase, its value had been dropped but the changes was not significant, and optimization condition was found at above 800 1 000 g carrier loading （pouzzolane） or 600 g PVC. Under gas/liquid ratio of 0.8% -5.2%, KLa was （0.62-1.37）×10^-2· s^-1.  相似文献   

Mutual point-winning probabilities (MPW): a new performance measure for table tennis     

Christophe Ley  Yves Dominicy  Wim Bruneel 《Journal of sports sciences》2018,36(23):2684-2690

ABSTRACT

We propose a new performance measure for table tennis players: the mutual point-winning probabilities (MPW) as server and receiver. The MPWs quantify a player’s chances to win a point against a given opponent, and hence nicely complement the classical match statistics history between two players. These new quantities are based on a Bradley-Terry-type statistical model taking into account the importance of individual points, since a rally at 8–2 in the first set is less crucial than a rally at the score of 9–9 in the final set. The MPWs hence reveal a player’s strength on his/her service against a given opponent as well as his/her capacity of scoring crucial points. We estimate the MPWs by means of maximum likelihood estimation and show via a Monte Carlo simulation study that our estimation procedure works well. In order to illustrate the MPWs’ versatile use, we have organized two round-robin tournaments of ten respectively eleven table tennis players from the Belgian table tennis federation. We compare the classical final ranking to the ranking based on MPWs, and we highlight how the MPWs shed new light on strengths and weaknesses of the players.  相似文献   

Comparison of two methodological approaches for the mechanical analysis of single-joint isoinertial movement using a customised isokinetic dynamometer*     

Mathieu Plautard  Gaël Guilhem  Vincent Fohanno  Antoine Nordez  Christophe Cornu 《Sports biomechanics / International Society of Biomechanics in Sports》2018,17(3):287-302

Compared to isokinetic and isometric tests, isoinertial movements have been poorly used to assess single-joint performance. Two calculation procedures were developed to estimate mechanical performance during single-joint isoinertial movements performed on a customised isokinetic dynamometer. The results were also compared to appreciate the effects of measurement systems and calculation procedures. Five participants performed maximal knee extensions at four levels of resistance (30, 50, 70 and 90% of the one-repetition maximum, 1-RM). Joint angular velocity and torque were assessed from customised isokinetic dynamometer measures (method A) and from weight stack kinematic (method B). Bland–Altman plots and mean percent differences (M_diff) were used to assess the level of agreement for mean and peak angular velocity and torque. A Passing–Bablok regression was performed to compare the angular velocity-angle and torque-angle relationships computed from the two analysis methods. The results showed a high level of agreement for all mechanical parameters (M_diff < 6% for all parameters). No statistically significant differences were observed between methods A and B in terms of angular velocity-angle and torque-angle relationships except at 30% of 1-RM for the torque-angle relationship. Both methodologies provide comparable values of angular velocity and torque, offering alternative approaches to assess neuromuscular function from single-joint isoinertial movements.  相似文献