Fragmentation, sliding and interface degradation in SiC/SiC composites

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THE RISE OF THE SUPER-ATHLETES, AND WHY THERE IS NO TURNING BACK

Born and raised in Beirut, bio-medical engineer Mounir is the co-founder and Managing Director of N3XT Sports Inc. A world citizen who is passionate about sports, technology, entrepreneurship, and innovation, he has 15+ years’ experience in various positions in the sports industry, the latest of which was Director of Technology and Innovation at the US Olympic Committee; he also sits on the working board of Women in Sports Tech. Mounir holds a PhD in Bioengineering, is fluent in four languages, and has recently moved with his wife and two children from the Silicon Valley to Barcelona. Mounir‘s expertise areas of wearable technology, smart textiles and fabric, Internet of Things (IoT), artificial intelligence and cognitive computing are of interest to sports biomechanists in their goal of improving sports performance. Mounir has extensive experiences creating, managing and advising technology start ups and with the US Olympic team. Mounir‘s keynote will stimulate biomechanists to think of new ways to help improve athlete’s results with technology

In-situ 3D visualization of composite microstructure during polymer-to-ceramic conversion

One route for producing fiber-reinforced ceramic-matrix composites entails repeated impregnation and pyrolysis of a preceramic polymer in a fiber preform. The process relies crucially on the development of networks of contiguous cracks during pyrolysis, thereby allowing further impregnation to attain nearly-full densification. The present study employs in-situ x-ray computed tomography (XCT) to reveal in three dimensions the evolution of matrix structure during pyrolysis of a SiC-based preceramic polymer up to temperatures of 1200°C. Observations are used to guide the development of a taxonomy of crack structures and to identify the temporal hierarchy of their formation. A quantitative analysis is employed to characterize effects of local microstructural dimensions on the conditions required to form cracks of various types. Complementary measurements of gas evolution and mass loss of the preceramic polymer during pyrolysis as well as changes in mass density and Young\u27s modulus provide context for the physical changes revealed by XCT. The findings provide a foundation for future development of physics-based models to guide composite fabrication processes

Comportamiento de yautía [Xanthosoma sagittifolium (L.) Schott] derivada de cultivo de tejido

To respond to questions raised about field adaptability of tissue culture derived (TC) cocoyam, a study was conducted to compare TC cocoyam with cocoyam from non-tissue culture (NTC), i.e., vegetatively propagated. Throughout the vegetative cycle, TC plants out performed NTC plants in terms of plant vigor and average leaf number. In general, TC plants acclimatized in the greenhouse produced significantly more suckers than NTC plants, regardless of the period within the growing season. In the trial, the average number of cormels per plant varied from 6.66 to 12.44. TC plants acclimatized for two months (h1), yielded higher than the other TC and TCN plants. The total weight (weight of cormels and corms) of TC plants of h1 was significantly higher than in all other treatments. This finding suggests the importance of the acclimatization process in preparing TC derived plantlets for field conditions.Para responder a preguntas sobre la adaptabilidad al campo de la yautía derivada de cultivo de tejido (CT), se comparó ésta con ia yautía no derivada de cultivo de tejido (NCT). Durante el ciclo vegetativo, las plantas CT superaron a las plantas NCT en términos de vigor de la planta y del número promedio de hojas. Por lo general, las plantas CT aclimatadas en el invernadero produjeron significativamente más hijuelos que las plantas NCT, sin importar la etapa de crecimiento de !a planta. El número promedio de cormelos por planta varió de 6.66 a 12.44. Las plantas CT aclimatadas por dos meses (h1) produjeron más cormelos que las otras plantas CT y que las plantas NCT. El peso total (peso de los cormelos y los cormos) de las plantas CT en h1  fue significativamente mayor que el peso total obtenido en los otros tratamientos. Este hallazgo sugiere la importancia del proceso de aclimatización en la preparación de las plantas derivadas de cultivo de tejido para las condiciones del campo

A case study of blogging as a web-based learning tool: The experience of six graduate students in a traditional educational setting

This study explored the narratives of six graduate students who experienced blogging as a learning tool in a graduate seminar on adult education at an English language university in Montreal. The main research question was: What are the experiences of blogging as a learning tool by graduate students in a traditional education setting? All six participants volunteered to be interviewed a few months after the end of the course. They were all female, white between 25 and 59 years of age, four married and two single. Five of the interviews took place face to face in person and one interview was conducted on Skype. Six major themes were identified and summarized under the following headings: Challenges of the course blog experience, running the blog experience, the impact of blogging on learning, Moodle versus Blogger, the impact of blogging on the traditional educational system, and the participants’ evaluation of the experience. The results, summarized in a table at the end of Chapter 3, resonate well in relation to the existing body of the literature on the topic and point towards further research projects. This case study adds rich data about the experience of learners with educational blogging to the existing literature with regard to implementing blogs in traditional classrooms in higher education. This thesis may also be of use for educators interested in integrating technology in traditional classrooms in order to promote an active and useful learning experience for students

Assessment of level-walking aperiodicity

BACKGROUND: In gait analysis, walking is assumed to be periodic for the sake of simplicity, despite the fact that, strictly speaking, it can only approximate periodicity and, as such, may be referred to as pseudo-periodic. This study aims at: 1) quantifying gait pseudo-periodicity using information concerning a single stride; 2) investigating the effects of walking pathway length on gait periodicity; 3) investigating separately the periodicity of the upper and lower body parts movement; 4) verifying the validity of foot-floor contact events as markers of the gait cycle period. METHODS: Ten young healthy subjects (6 males, 23 ± 5 years) were asked to perform various gait trials, first along a 20-m pathway that allowed reaching a steady-state condition, and then along an 8-m pathway. A stereophotogrammetric system was used to reconstruct the 3D position of reflective markers distributed over the subjects' body. Foot contact was detected using an instrumented mat. Three marker clusters were used to represent the movement of the whole body, the upper body (without upper limbs), and the lower body, respectively. Linear and rotational kinetic, and gravitational and elastic potential "energy-like" quantities were used to calculate an index J(t) that described the instantaneous "mechanical state" of the analysed body portion. The variations of J(t) in time allowed for the determination of the walking pseudo-period and for the assessment of gait aperiodicity. RESULTS: The suitability of the proposed approach was demonstrated, and it was shown that, for young, healthy adults, a threshold of physiological pseudo-periodicity of walking at natural speed could be set. Higher pseudo-periodicity values were found for the shorter pathway only for the upper body. Irrespective of pathway length, the upper body had a larger divergency from periodicity than the lower body. The error that can be made in estimating the gait cycle duration for the upper body from the heel contacts was shown to be significant. CONCLUSION: The proposed method can be easily implemented in gait laboratories to verify the consistency of a recorded stride with the hypothesis of periodicity

Język polski w krainie kangurów. Robert Dębski, „Dwujęzyczność angielsko-polska w Australii. Języki mniejszościowe w dobie globalizacji i informatyzacji”, Wydawnictwo Uniwersytetu Jagiellońskiego, Kraków 2009, ss. 249

Recenzja książki Roberta Dębskiego: „Dwujęzyczność angielsko-polska w Australii. Języki mniejszościowe w dobie globalizacji i informatyzacji”, Wydawnictwo Uniwersytetu Jagiellońskiego, Kraków 2009, ss. 249