Design of all electric secondary power system for future advanced MALE UAV

SAvE (Systems for UAV Alternative Energy) is a research project funded in 2007 by Piemonte Regional Government, Italy, and assigned to Politecnico di Torino and Alenia Aeronautica. Aim of the project is the study of new, more efficient, more effective and more environmentally friendly on board systems for future advanced Unmanned Aerial Vehicles (UAV), particularly for future advanced MALE UAVs. The paper deals with the analysis and design of the all electric Secondary Power System of a future advanced MALE UAV, that we consider as "reference aircraft". After a thorough trade-off analysis of different configurations of the Secondary Power System, the hybrid configuration, characterized by generators (or better, starter/generators), fuel cells and traditional and innovative batteries, has been selected as the most promising. Detailed investigations to find the best way to apportion the supply of secondary power, considering the various power sources (generators or starter/generators, batteries and fuel cells) in the different modes of operations, have been performed thanks to an integrated simulation environment, where physical, functional and mission scenario simulations continuously exchange data and results

Rational and affordable concepts of Landing Gear for small reentry vehicle demonstrators

The paper proposes an innovative solution for landing gear of small space vehicles, in particular of technological demonstrators of reentry space vehicles. After explaining why small space vehicles can benefit from landing gears, the work investigates a solution, which avoids the use of fluidic systems and minimizes constraints on the whole vehicle, thus limiting cost raising and making the installation of the landing gear easier on vehicles that originally did not envisage landing gears

Many-body models for molecular nanomagnets

We present a flexible and effective ab-initio scheme to build many-body models for molecular nanomagnets, and to calculate magnetic exchange couplings and zero-field splittings. It is based on using localized Foster-Boys orbitals as one-electron basis. We apply this scheme to three paradigmatic systems, the antiferromagnetic rings Cr8 and Cr7Ni and the single molecule magnet Fe4. In all cases we identify the essential magnetic interactions and find excellent agreement with experiments.Comment: 5 pages, 3 figure

Electromechanical Quantum Simulators

Digital quantum simulators are among the most appealing applications of a quantum computer. Here we propose a universal, scalable, and integrated quantum computing platform based on tunable nonlinear electromechanical nano-oscillators. It is shown that very high operational fidelities for single and two qubits gates can be achieved in a minimal architecture, where qubits are encoded in the anharmonic vibrational modes of mechanical nanoresonators, whose effective coupling is mediated by virtual fluctuations of an intermediate superconducting artificial atom. An effective scheme to induce large single-phonon nonlinearities in nano-electromechanical devices is explicitly discussed, thus opening the route to experimental investigation in this direction. Finally, we explicitly show the very high fidelities that can be reached for the digital quantum simulation of model Hamiltonians, by using realistic experimental parameters in state-of-the art devices, and considering the transverse field Ising model as a paradigmatic example.Comment: 14 pages, 8 figure

Optimized Confinement of Fermions in Two Dimensions

One of the challenging features of studying model Hamiltonians with cold atoms in optical lattices is the presence of spatial inhomogeneities induced by the confining potential, which results in the coexistence of different phases. This paper presents Quantum Monte Carlo results comparing meth- ods for confining fermions in two dimensions, including conventional diagonal confinement (DC), a recently proposed 'off-diagonal confinement' (ODC), as well as a trap which produces uniform den- sity in the lattice. At constant entropy and for currently accessible temperatures, we show that the current DC method results in the strongest magnetic signature, primarily because of its judicious use of entropy sinks at the lattice edge. For d-wave pairing, we show that a constant density trap has the more robust signal and that ODC can implement a constant density profile. This feature is important to any prospective search for superconductivity in optical lattices

The Crip, The Fat and The Ugly in an Age of Austerity: Resistance, Reclamation and Affirmation

Welcome to this special forum, The Crip, The Fat and The Ugly in an Age of Austerity: Resistance, Reclamation and Affirmation. Our original desire in putting out this call was to critically explore the processes and politics of austerity upon diverse and marginalized embodiments in neoliberal and advanced capitalist times. Global austerity has a far reach, often into, around, behind, beyond and alongside the body. Global austerity routinely categorizes body-minds[i] in terms of productivity, value, cost, ability and aesthetics. Body-minds are positioned vis-a-vis global austerity as a site for social order, economic possibility, progression, and big business. Whereas “[a]n able body is the body of a citizen; deformed deafened, amputated, obese, female, perverse, crippled, maimed and blinded bodies do not make up the body politic” (Davis, 1995, pp. 71–72). In devising this forum, we yearned for space to contemplate the aesthetics, experiences and the reification of body-minds - how capitalism makes sense of and shapes body-minds; the ways in which austerity both marks and produces bodies and selves, and the means through which these are further shaped by disability, race, class, gender, age, size, sexuality, and nation. Although we explore aspects of these in our own work (Liddiard, 2018; Slater, 2015), we wanted to create a space to connect with others and think about diverse and marginalized embodiments in austere times. In this introduction, we story the process through which we put the issue together, from our original decision making and putting out the call, to supporting authors to revise their contributions. We do so because we feel it’s a fitting way to speak to the inclusions and exclusions made in this forum. At the same time, we feel it offers a broader commentary as to the “state” of global disability studies today

Quantum Monte Carlo estimators for the positron-electron annihilation rate in bound and low-energy scattering states

Variational and exact estimators for the positron-electron annihilation rate in bound states of systems containing a positron in the framework of quantum Monte Carlo methods are presented. The modification needed to compute the effective number of electrons Z(eff) when scattering states are concerned is also discussed. The algorithms are tested against four cases for which close to exact results are available, finding an overall good agreement. The systems are Ps(-), PsH, and the s-wave scattering component of e(+)H and e(+)He