1,115 research outputs found
The role of robotics in computer controlled polishing of large and small optics
Following formal acceptance by ESO of three 1.4m hexagonal off-axis prototype mirror segments, one circular segment, and certification of our optical test facility, we turn our attention to the challenge of segment mass-production. In this paper, we focus on the role of industrial robots, highlighting complementarity with Zeeko CNC polishing machines, and presenting results using robots to provide intermediate processing between CNC grinding and polishing. We also describe the marriage of robots and Zeeko machines to automate currently manual operations; steps towards our ultimate vision of fully autonomous manufacturing cells, with impact throughout the optical manufacturing community and beyond
'I would rather die': reasons given by 16-year-olds for not continuing their study of mathematics
Improving participation rates in specialist mathematics after the subject ceases to be compulsory at age 16 is part of government policy in England. This article provides independent and recent support for earlier findings concerning reasons for non- participation, based on free response and closed items in a questionnaire with a sample of over 1500 students in 17 schools, close to the moment of choice. The analysis supports findings that perceived difficulty and lack of confidence are important reasons for students not continuing with mathematics, and that perceived dislike and boredom, and lack of relevance, are also factors. There is a close relationship between reasons for non-participation and predicted grade, and a weaker relation to gender. An analysis of the effects of schools, demonstrates that enjoyment is the main factor differentiating schools with high and low participation indices. Building on discussion of these findings, ways of improving participation are briefly suggested
Robotic automation in computer controlled polishing
We first present a Case Study â the manufacture of 1.4 m prototype mirror-segments for the European Extremely Large Telescope, undertaken by the National Facility for Ultra Precision Surfaces, at the OpTIC facility operated by Glyndwr University. Scale-up to serial-manufacture demands delivery of a 1.4 m off-axis aspheric hexagonal segment with surface precision < 10 nm RMS every four days, compared with a typical year or more for an one-off part. This requires a radically-new approach to large optics fabrication, which will inevitably propagate into wider industrial optics. We report on how these ambitious requirements have stimulated an investigation into the synergy between robots and computer numerically controlled (âCNCâ) polishing machines for optical fabrication. The objective was not to assess which is superior. Rather, it was to understand for the first time their complementary properties, leading us to operate them together as a unit, integrated in hardware and software. Three key areas are reported. First is the novel use of robots to automate currently-manual operations on CNC polishing machines, to improve work-throughput, mitigate risk of damage to parts, and reduce dependence on highly-skilled staff. Second is the use of robots to pre-process surfaces prior to CNC polishing, to reduce total process time. The third draws the threads together, describing our vision of the automated manufacturing cell, where the operator interacts at cell rather than machine level. This promises to deliver a step-change in end-to-end manufacturing times and costs, compared with either platform used on its own or, indeed, the state-of-the-art used elsewhere
Effect of magnetic state on the transition in iron: First-principle calculations of the Bain transformation path
Energetics of the fcc () - bcc () lattice transformation by
the Bain tetragonal deformation is calculated for both magnetically ordered and
paramagnetic (disordered local moment) states of iron. The first-principle
computational results manifest a relevance of the magnetic order in a scenario
of the - transition and reveal a special role of the Curie
temperature of -Fe, , where a character of the transformation is
changed. At a cooling down to the temperatures one can expect that
the transformation is developed as a lattice instability whereas for
it follows a standard mechanism of creation and growth of an embryo of the new
phase. It explains a closeness of to the temperature of start of the
martensitic transformation, .Comment: 4 pages, 3 figures, submitted in Phys. Rev. Letter
Contacting the spirits of the dead: paranormal belief and the teenage worldview
A number of previous studies have examined both the overall level of belief expressed by young people in the paranormal and the major demographic predictors of such belief. Building on this research tradition, the present study examines how one specific paranormal belief concerning contact with the spirits of the dead integrates with the wider teenage worldview. Data provided by 33,982 pupils age 13 to 15 years throughout England and Wales demonstrated that almost one in three young people (31%) believed that it is possible to contact the spirits of the dead. Compared with young people who did not share this belief, the young people who believed in the possibility of contacting the spirits of the dead displayed lower psychological wellbeing, higher anxiety, greater isolation, greater alienation, less positive social attitudes, and less socially conforming lifestyles. Overall, paranormal beliefs seem to be associated with a less healthy worldview, in both personal and social terms
Engaging with issues of emotionality in mathematics teacher education for social justice
This article focuses on the relationship between social justice, emotionality and mathematics teaching in the context of the education of prospective teachers of mathematics. A relational approach to social justice calls for giving attention to enacting socially-just relationships in mathematics classrooms. Emotionality and social justice in teaching mathematics variously intersect, interrelate or interweave. An intervention, usng creative action methods, with a cohort of prospective teachers addressing these issues is described to illustrate the connection between emotionality and social justice in the context of mathematics teacher education. Creative action methods involve a variety of dramatic, interactive and experiential tools that can promote personal and group engagement and embodied reflection. The intervention aimed to engage the prospective teachers with some key issues for social justice in mathematics education through dialogue about the emotionality of teaching and learning mathematics. Some of the possibilities and limits of using such methods are considered
Around the tangent cone theorem
A cornerstone of the theory of cohomology jump loci is the Tangent Cone
theorem, which relates the behavior around the origin of the characteristic and
resonance varieties of a space. We revisit this theorem, in both the algebraic
setting provided by cdga models, and in the topological setting provided by
fundamental groups and cohomology rings. The general theory is illustrated with
several classes of examples from geometry and topology: smooth quasi-projective
varieties, complex hyperplane arrangements and their Milnor fibers,
configuration spaces, and elliptic arrangements.Comment: 39 pages; to appear in the proceedings of the Configurations Spaces
Conference (Cortona 2014), Springer INdAM serie
La comunicazione interculturale e lâapproccio comunicativo: dallâidea allo strumento
il saggio si inserisce in un filone di ricerca aperto nel 199 e proseguito con saggi e volumi: in questo caso di descrive e discute la progettazione di un passo fondamentale, dall'elaborazione teorica del modello di riferimento alla traduzione di tale modello in strumento operativo per la consultazione e la didattica
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