11,922 research outputs found
Real-time edge tracking using a tactile sensor
Object recognition through the use of input from multiple sensors is an important aspect of an autonomous manipulation system. In tactile object recognition, it is necessary to determine the location and orientation of object edges and surfaces. A controller is proposed that utilizes a tactile sensor in the feedback loop of a manipulator to track along edges. In the control system, the data from the tactile sensor is first processed to find edges. The parameters of these edges are then used to generate a control signal to a hybrid controller. Theory is presented for tactile edge detection and an edge tracking controller. In addition, experimental verification of the edge tracking controller is presented
Active Brownian Motion Tunable by Light
Active Brownian particles are capable of taking up energy from their
environment and converting it into directed motion; examples range from
chemotactic cells and bacteria to artificial micro-swimmers. We have recently
demonstrated that Janus particles, i.e. gold-capped colloidal spheres,
suspended in a critical binary liquid mixture perform active Brownian motion
when illuminated by light. In this article, we investigate in some more details
their swimming mechanism leading to active Brownian motion. We show that the
illumination-borne heating induces a local asymmetric demixing of the binary
mixture generating a spatial chemical concentration gradient, which is
responsible for the particle's self-diffusiophoretic motion. We study this
effect as a function of the functionalization of the gold cap, the particle
size and the illumination intensity: the functionalization determines what
component of the binary mixture is preferentially adsorbed at the cap and the
swimming direction (towards or away from the cap); the particle size determines
the rotational diffusion and, therefore, the random reorientation of the
particle; and the intensity tunes the strength of the heating and, therefore,
of the motion. Finally, we harness this dependence of the swimming strength on
the illumination intensity to investigate the behaviour of a micro-swimmer in a
spatial light gradient, where its swimming properties are space-dependent
Sustainability, stakeholders and business. Editorial
Over the past 20 years, there has been an increasing attention on the drivers of value in organizations. Both the strategic management literature and practice have remarked the importance for managers to be aware of the impact of firm activities, products and services on either the external and internal environment and, more generally, on all firm stakeholders. The emergence of the notions of “sustainable development” and “sustainability” reflects a profound change in global thinking, which forces firms to move beyond trade-offs between business and society
Low energy neutrino scattering measurements at future Spallation Source facilities
In the future several Spallation Source facilities will be available
worldwide. Spallation Sources produce large amount of neutrinos from
decay-at-rest muons and thus can be well adapted to accommodate
state-of-the-art neutrino experiments. In this paper low energy neutrino
scattering experiments that can be performed at such facilities are reviewed.
Estimation of expected event rates are given for several nuclei, electrons and
protons at a detector located close to the source. A neutrino program at
Spallation Sources comprises neutrino-nucleus cross section measurements
relevant for neutrino and core-collapse supernova physics, electroweak tests
and lepton-flavor violation searches.Comment: 12 pages, 4 figures, 5 table
What about a beta-beam facility for low energy neutrinos?
A novel method to produce neutrino beams has recently been proposed : the
beta-beams. This method consists in using the beta-decay of boosted radioactive
nuclei to obtain an intense, collimated and pure neutrino beam. Here we propose
to exploit the beta-beam concept to produce neutrino beams of low energy. We
discuss the applications of such a facility as well as its importance for
different domains of physics. We focus, in particular, on neutrino-nucleus
interaction studies of interest for various open issues in astrophysics,
nuclear and particle physics. We suggest possible sites for a low energy
beta-beam facility.Comment: 4 pages, 1 figur
-deformed harmonic oscillators
We analyze systematically several deformations arising from two-dimensional
harmonic oscillators which can be described in terms of -pseudo
bosons. They all give rise to exactly solvable models, described by non
self-adjoint hamiltonians whose eigenvalues and eigenvectors can be found
adopting the quite general framework of the so-called -pseudo bosons.
In particular, we show that several models previously introduced in the
literature perfectly fit into this scheme.Comment: in press in International Journal of Theoretical Physic
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