A manipulator arm for zero-g simulations

A 12-ft counterbalanced Slave Manipulator Arm (SMA) was designed and fabricated to be used for resolving the questions of operational applications, capabilities, and limitations for such remote manned systems as the Payload Deployment and Retrieval Mechanism (PDRM) for the shuttle, the Free-Flying Teleoperator System, the Advanced Space Tug, and Planetary Rovers. As a developmental tool for the shuttle manipulator system (or PDRM), the SMA represents an approximate one-quarter scale working model for simulating and demonstrating payload handling, docking assistance, and satellite servicing. For the Free-Flying Teleoperator System and the Advanced Tug, the SMA provides a near full-scale developmental tool for satellite servicing, docking, and deployment/retrieval procedures, techniques, and support equipment requirements. For the Planetary Rovers, it provides an oversize developmental tool for sample handling and soil mechanics investigations. The design of the SMA was based on concepts developed for a 40-ft NASA technology arm to be used for zero-g shuttle manipulator simulations

Working with grammar as a tool for making meaning

A focus on sentence-level grammar in student writing has often been associated with a top-down prescriptiveness in which ‘peremptory commands’ about correct usage are linked with a negative evaluation of a person’s speech or writing’ (Cameron 2007). Yet, grammar is frequently a concern that pre-occupies both students and the academics assessing their writing. This chapter explores some more transformative ways in which this concern could be addressed by enabling students to investigate the relationship between grammar, their identities and the complex power relationships within the university. It focuses on a small-scale project in which a number of Education Studies students were referred to a writing specialist in order to improve their ‘poor grammar’. Closer examination of the student assignments revealed a complex range of grammatical ‘mistakes’, ranging from grammatical forms frequently considered correct in non-British varieties of English, such as Indian or Nigerian English (Kirkpatrick 2007); non-standard forms of grammar used by students from the local communities in London (Preece 2009) ; and errors which could be attributed to the inter-language of non-native speakers of English (usually international students) still acquiring British standard English (Selinker 1972). Many of the students who were referred felt heavily stigmatised, and in order to redress this, a series of classroom activities were devised. These aimed to foster reflection on different varieties of English and student identities, and provide contrastive analysis and improved strategies for ‘noticing’ of varied grammatical forms and their appropriacy in different contexts. The chapter concludes by suggesting that more dialogic feedback from academic staff regarding grammar will enable students to conceptualise grammar as a tool for making meaning in different contexts

Construction of nonlocal light-cone operators with definite twist

A systematic procedure is introduced to uniquely decompose nonlocal LC-operators into harmonic operators of well defined geometric twist. The method will be demonstrated for (pseudo)scalar, (axial) vector and skew tensor bilocal quark light-ray operatorsComment: 4 pages, AMSTeX, Contribution to 7th Int. Workshop on Deep Inelastic Scatterin and QCD, Zeuthen, April 1999 change of formulas 25 and 2

Electromagnetic cyclotron instabilities in bi-Kappa distributed plasmas : a quasilinear approach

Anisotropic bi-Kappa distributed plasmas, as encountered in the solar wind and planetary magnetospheres,are susceptible to a variety of kinetic instabilities including the cyclotron instabilities driven by an excess ofperpendicular temperature T⊥ > T∥ (where ∥, ⊥ denote directions relative to the mean magnetic field). Theseinstabilities have been extensively investigated in the past, mainly limiting to a linear stability analysis. Abouttheir quasilinear (weakly nonlinear) development some insights have been revealed by numerical simulationsusing PIC and Vlasov solvers. This paper presents a self-consistent analytical approach, which provides forboth the electron and proton cyclotron instabilities an extended picture of the quasilinear time evolution ofthe anisotropic temperatures as well as the wave energy densities

Model predictive eco-driving control for heavy-duty trucks using Branch and Bound optimization

Eco-driving (ED) can be used for fuel savings in existing vehicles, requiring only a few hardware modifications. For this technology to be successful in a dynamic environment, ED requires an online real-time implementable policy. In this work, a dedicated Branch and Bound (BnB) model predictive control (MPC) algorithm is proposed to solve the optimization part of an ED optimal control problem. The developed MPC solution for ED is based on the following ingredients. As a prediction model, the velocity dynamics as a function of distance is modeled by a finite number of driving modes and gear positions. Then we formulate an optimization problem that minimizes a cost function with two terms: one penalizing the fuel consumption and one penalizing the trip duration. We exploit contextual elements and use a warm-started solution to make the BnB solver run in real-time. The results are evaluated in numerical simulations on two routes in Israel and France and the long haul cycle of the Vehicle Energy consumption Calculation Tool (VECTO). In comparison with a human driver and a Pontryagin's Minimum Principle (PMP) solution, 25.8% and 12.9% fuel savings, respectively, are achieved on average