Experimental Validation of Contact Dynamics for In-Hand Manipulation

This paper evaluates state-of-the-art contact models at predicting the motions and forces involved in simple in-hand robotic manipulations. In particular it focuses on three primitive actions --linear sliding, pivoting, and rolling-- that involve contacts between a gripper, a rigid object, and their environment. The evaluation is done through thousands of controlled experiments designed to capture the motion of object and gripper, and all contact forces and torques at 250Hz. We demonstrate that a contact modeling approach based on Coulomb's friction law and maximum energy principle is effective at reasoning about interaction to first order, but limited for making accurate predictions. We attribute the major limitations to 1) the non-uniqueness of force resolution inherent to grasps with multiple hard contacts of complex geometries, 2) unmodeled dynamics due to contact compliance, and 3) unmodeled geometries dueto manufacturing defects.Comment: International Symposium on Experimental Robotics, ISER 2016, Tokyo, Japa

Sustainability, Globalization, and the Energy Sector Europe in a Global Perspective

International audienceThis paper analyzes the socio-economic effects of energy sustainability challenges raised by oil depletion and climate change at the European and global level. We assess macroeconomic impacts at different time horizons over 2010-2100 and under different visions of the future of globalization . Fragmented capital markets affect the pace and direction of change and induce additional economic losses in the long term. Regionalized good markets have a positive effect in the long term since less intense international trade moderates the effects of fossil fuel constraints. A sustainable energy future will require implementing policies and measures that are able to (i) provide correct incentives for long-term investments by resorting to other signals than current market prices, (ii) incorporate sectoral measures that act complementarily to pricing schemes measures for sectors confronted with biased agents’ behaviors or strong inertias, (iii) foster globalization patterns that are consistent with energy sustainability objectives. The challenge consists in articulating the objectives and the instruments of these different policy and measures triggering the transition towards sustainable future

Ultraestructura de la red alveolar y su relación con el recubrimiento de las paredes vasculares en olmos infectados con Ophiostoma novo-ulmi y en otras plantas infectadas con enfermedades similares de marchitamiento

In elms infected with Dutch elm disease, alveolar networks, demarcated by filamentous-like bands and confluent with similar matter (the coating) accumulating on vessel walls, occurred regularly in vessel elements. Similar material lined vessel walls in inoculated, sterilized, thin elm wood sections fixed by high pressure freezing. The coating was observed to connect with fungal cells and occasionally contained small opaque particles, the size of ribosomes, membranous and vesicular structures, and, following incubation of wood chips taken from diseased samples incubated on an agar medium, it still displayed similar matter. Coating and alveolar bands increased in thickness by confluence of other bands or membranous structures. Similar matter and structures also occurred in other plants affected by similar fungal wilt diseases. In all systems, the compact coating did not label for chitin, cellulose and pectin. In staghorn sumac, the probe for DNA attached to the coating. Altogether, in the light of these data, it appears that the coating and alveolar networks are not inert components, a fact which indicates their primordial probable pathogen origin. It is proposed that these elements might be important not only in the initial infection stages but also in older or recurrent infections at a time when host resistance mechanisms are ineffective.En olmos afectados por la grafiosis, la red alveolar, demarcada por bandas filamentosas, y confluente con acumulaciones de la misma sustancia (cubrición) presentes en las paredes de los vasos, aparece regularmente en los elementos conductores. Sustancias similares tapizan las paredes de los vasos en secciones de madera delgada de olmo inoculada y esterilizada, y posteriormente criofijadas a altas presiones. Se observó que la cubrición se conecta con las células del micelio y que ocasionalmente contenía pequeñas partículas opacas del tamaño de los ribosomas, estructuras membranosas y vesiculares, así como que, tras la incubación de astillas leñosas cogidas de muestras enfermas incubadas en agar, aún se presentaba una sustancia similar. La cubrición y las bandas alveolares aumentaron su espesor en la confluencia con otras bandas o estructuras membranosas. Estructuras y sustancias similares aparecieron también en otras plantas afectadas por enfermedades similares originadas por hongos que producen marchitamiento. En todos los sistemas, la cubrición compacta no pudo ser marcada como quitina, celulosa ni pectina. En zumaque (Rhus typhina), la sonda de ADN se pegó a la cubrición. En resumen, a la vista de estos datos, parece ser que la cubrición y la red alveolar no están formados por componentes inertes, un hecho que indica su probable origen patogénico. Se sugiere que esos elementos podrían ser importantes no sólo en las fases iniciales de la infección, sino también, en infecciones más desarrolladas o recurrentes, en el momento en que los mecanismos de resistencia del hospedante no son efectivos

Not All the Organelles of Living Cells Are Equal! Or Are They? Engaging Students in Deep Learning and Conceptual Change

The cell is the fundamental basis for understanding biology much like the atom is the fundamental basis for understanding physics. Understanding biology requires the understanding of the fundamental functions performed by components within each cell. These components, or organelles, responsible for both maintenance and functioning of the cell comprise to form a dynamically stable ecosystem.  The secret of achieving this noble and desirable efficiency rely on the structural and functional variations of the organelles within the cell; they each carry out specific jobs within the cell resulting in a smooth, running process that would be the envy of any industrial manager. In this role-playing learning activity, we aim to engage students in deep learning that leads to cognitive and conceptual change by forcing them to be and to actively act as those organelles within the cell.  It is centered on the idea that a number of organelles within the eukaryotic cells are strongly “protesting” the “privilege” that mitochondria and chloroplasts have within the living cells (both in single and multi-cellular organisms).  They are protesting the structural and functional privileges that other organelles lack, but the mitochondria and chloroplasts have. Students will have to understand an explore the reasons for the differences among all the organelles and how they differ in importance and function, especially in regards to interactions between organelles within each cell and how it contributes to the life of the cell as a whole..  After all, as it has been stated by NGS (2007) “a human cell reveals our inner architecture” (p. 40). Keywords: Living cells, organelles, role-playing, analogy, instructional approach, intentional learners, student success

Structural and magnetic properties of Co2MnSi thin films

Co2MnSi (CMS) films of different thicknesses (20, 50, and 100 nm) were grown by radio frequency (RF) sputtering on a-plane sapphire substrates. Our X-rays diffraction (XRD) study shows that, in all the samples, the cubic 〈110〉 CMS axis is normal to the substrate and that six well defined preferential in-plane orientations are present. Static and dynamic magnetic properties were investigated using vibrating sample magnetometry (VSM) and microstrip line ferromagnetic resonance (MS-FMR), respectively. From the resonance measurements versus the direction and the amplitude of an applied magnetic field, most of the magnetic parameters are derived, i.e.: the magnetization, the gyromagnetic factor, the exchange stiffness coefficient, and the magnetic anisotropy terms. The in-plane anisotropy results from the superposition of two terms showing a twofold and a fourfold symmetry, respectively. The observed behavior of the hysteresis loops is in agreement with this complex form of the in-plane anisotropy.International audienceCo2MnSi (CMS) films of different thicknesses (20, 50, and 100 nm) were grown by radio frequency (RF) sputtering on a-plane sapphire substrates. Our X-rays diffraction (XRD) study shows that, in all the samples, the cubic 〈110〉 CMS axis is normal to the substrate and that six well defined preferential in-plane orientations are present. Static and dynamic magnetic properties were investigated using vibrating sample magnetometry (VSM) and microstrip line ferromagnetic resonance (MS-FMR), respectively. From the resonance measurements versus the direction and the amplitude of an applied magnetic field, most of the magnetic parameters are derived, i.e.: the magnetization, the gyromagnetic factor, the exchange stiffness coefficient, and the magnetic anisotropy terms. The in-plane anisotropy results from the superposition of two terms showing a twofold and a fourfold symmetry, respectively. The observed behavior of the hysteresis loops is in agreement with this complex form of the in-plane anisotropy

UNDRAINED BEARING CAPACITY OF EMBEDDED STRIP FOOTINGS UNDER VERTICAL AND HORIZONTAL LOADS

This paper is concerned with the undrained bearing capacity of embedded strip footing under inclined loading (i.e. combined vertical and horizontal). A series of numerical computations using the finite-difference code Fast Lagrangian Analysis of Continua (FLAC) was carried out to evaluate the failure envelopes in vertical force – horizontal force (V-H) plane, using both probe and swipe analyses. The adopted approach involves a numerical solution of the equations governing elasto-plastic soils. The soil is modeled by an elasto-plastic model with a Tresca criterion. The results are presented in terms of the failure envelope in vertical and horizontal loading plane. 

Has the Time Come to Start a Dialogue About the Role of Nutrition and Our Inner Microbiomes In Education? Teacher and Faculty Perspectives

The purpose of this study is to determine if educational professionals at the high school and college levels believe that their students should be required to complete a Health and Nutrition and/or a Microbiology course for graduation. The study used both a descriptive survey and a questionnaire as data collection instruments. The study population was comprised of 655 teachers and instructors from high schools, colleges and universities across the U.S.A.   Quantitative analysis was conducted using descriptive statistics. Qualitative analysis of open ended responses was organized into multiple themes. While all the participants strongly agreed that our nation (U.S.A.) is facing critical challenges in overcoming the new trends in obesity, diabetes, infectious diseases and other related epidemics, as well as on the role of education in solving the matters, they differ on what to do and how to prepare the current and future generations. At the college level, while over half of all the participants (61.22%) preferred to see Microbiology as a part of the graduation requirement from college, only 41.22% of the same participants felt comfortable in making Nutrition a part of the graduation requirement.  At the high school level, while 42.59% of all the participants saw no problem in including Nutrition as a part of the graduation requirement from high school, only 10.53% of the same participants felt comfortable including Microbiology as a graduation requirement from high school.  More detailed outcomes are presented in this paper. However, more participating college instructors compared to high school teachers did not think either of the topics should be mandated for graduation from high school or college; the only exception would be if these two fields of study were part of their selected academic program. Instead, this group of participants suggested making changes to existing course design and content (such as the required “health” or Biology classes), which would offer valuable additions to the existing curriculum and prepare students in health and nutrition. Finally, almost all of the participants provided various reasons and justifications for their perspectives on the matter.  The study also shows a significant role for administrators and academic leaders in this requirement process (decision making process for the curricula). Recommendations based on the findings are provided and discussed below. Keywords: General education, Nutrition, Microbiology, Human Microbiomes, Obesity, Diabetes, Illness prevention, Infectious diseases, Education, burden of disease, educational reform

NUMERICAL STUDY OF DEPTH FACTORS FOR UNDRAINED LIMIT LOAD OF STRIP FOOTINGS

Current studies of bearing capacity for shallow foundations tend to rely on the hypothesis of an isolated footing lying on the ground surface. In practice a footing never lies on the ground surface; it is mostly embedded at a depth D below the ground surface. This paper focuses on a numerical study using the finite-difference code Fast Lagrangian Analysis of Continua(FLAC),to evaluate the bearing capacity of embedded strip footings. The effect of the embedment is estimated though a depth factor, defined as a ratio of the bearing capacity of a strip footing at a depth Dto that of a strip footing at the ground surface. The results presented in this paper show that the size and shape of the shear zone and displacement field defining the undrained capacity of shallow foundations under centred vertical loading are dependent on embedment rati