966 research outputs found
Fragmentation Experiment and Model for Falling Mercury Drops
The experiment consists of counting and measuring the size of the many
fragments observed after the fall of a mercury drop on the floor. The size
distribution follows a power-law for large enough fragments. We address the
question of a possible crossover to a second, different power-law for small
enough fragments. Two series of experiments were performed. The first uses a
traditional film photographic camera, and the picture is later treated on a
computer in order to count the fragments and classify them according to their
sizes. The second uses a modern digital camera. The first approach has the
advantage of a better resolution for small fragment sizes. The second, although
with a poorer size resolution, is more reliable concerning the counting of all
fragments up to its resolution limit. Both together clearly indicate the real
existence of the quoted crossover.
The model treats the system microscopically during the tiny time interval
when the initial drop collides with the floor. The drop is modelled by a
connected cluster of Ising spins pointing up (mercury) surrounded by Ising
spins pointing down (air). The Ising coupling which tends to keep the spins
segregated represents the surface tension. Initially the cluster carries an
extra energy equally shared among all its spins, corresponding to the coherent
kinetic energy due to the fall. Each spin which touches the floor loses its
extra energy transformed into a thermal, incoherent energy represented by a
temperature used then to follow the dynamics through Monte Carlo simulations.
Whenever a small piece becomes disconnected from the big cluster, it is
considered a fragment, and counted. The results also indicate the existence of
the quoted crossover in the fragment-size distribution.Comment: 6 pages, 3 figure
Allan Variance Analysis as Useful Tool to Determine Noise in Various Single-Molecule Setups
One limitation on the performance of optical traps is the noise inherently
present in every setup. Therefore, it is the desire of most experimentalists to
minimize and possibly eliminate noise from their optical trapping experiments.
A step in this direction is to quantify the actual noise in the system and to
evaluate how much each particular component contributes to the overall noise.
For this purpose we present Allan variance analysis as a straightforward
method. In particular, it allows for judging the impact of drift which gives
rise to low-frequency noise, which is extremely difficult to pinpoint by other
methods. We show how to determine the optimal sampling time for calibration,
the optimal number of data points for a desired experiment, and we provide
measurements of how much accuracy is gained by acquiring additional data
points. Allan variances of both micrometer-sized spheres and asymmetric
nanometer-sized rods are considered.Comment: 14 pages, 6 figures, presented at SPIE Optics+Photonics 2009 in San
Diego, CA, US
Newcastle Business School Principles of Responsible Management Education Project (NBS PRIME)
The world is changing rapidly and new demands face business leaders to deal with the planet and environment more sustainably, to deal with the numerous societies their organisations operate in more equitably and with greater cultural understanding, and to be more open, transparent and responsible with respect to their stakeholders. Recent events such as the credit and banking crisis alongside general global corporate social responsibility and sustainability concerns, have led to questions as to whether current management education is adequate to equip and develop future leaders with the requisite skills to meet
these new demands (Colby, Ehrlich, Sullivan, Dolle, & Shulman, 2011; Datar, Garvin, & Cullen, 2010; Weybrecht, 2010).
For these reasons it is essential that universities and business schools seek to embrace principles of sustainability and responsible management into their teaching, research and enterprise activities.
Newcastle Business school is ideally placed to make a significant contribution to social, environmental and economic well being through its global reputation for delivering some of the best business management education in the UK
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