3,516 research outputs found
Glass transition in Ultrathin Polymer Films : A Thermal Expansion Study
Glass transition process gets affected in ultrathin films having thickness
comparable to the size of the molecules. We observe systematic broadening of
glass transition temperature (Tg) as the thickness of the polymer film reduces
below the radius of gyration but the change in the average Tg was found to be
very small. Existence of reversible negative and positive thermal expansion
below and above Tg increased the sensitivity of our thickness measurements
performed using energy dispersive x-ray reflectivity. A simple model of Tg
variation as a function of depth expected from sliding motion could explain the
results. We observe clear glass transition even for 4 nm polystyrene film that
was predicted to be absent from ellipsometry measurements of thicker films.Comment: 11 pages, 5 figure
Extended supernova shock breakout signals from inflated stellar envelopes
Stars close to the Eddington luminosity can have large low-density inflated
envelopes. We show that the rise times of shock breakout signals from
supernovae can be extended significantly if supernova progenitors have an
inflated stellar envelope. If the shock breakout occurs in such inflated
envelopes, the shock breakout signals diffuse in them, and their rise time can
be significantly extended. Then, the rise times of the shock breakout signals
are dominated by the diffusion time in the inflated envelope rather than the
light-crossing time of the progenitors. We show that our inflated Wolf-Rayet
star models whose radii are of the order of the solar radius can have shock
breakout signals which are longer than ~100 sec. The existence of inflated
envelopes in Wolf-Rayet supernova progenitors may be related to the mysterious
long shock breakout signal observed in Type Ib SN 2008D. Extended shock
breakout signals may provide evidence for the existence of inflated stellar
envelopes and can be used to constrain the physical properties of these
enigmatic structures.Comment: 5 pages, 3 figures, 1 table, accepted by Astronomy & Astrophysics
Letters, proofed in v
Generating 3D faces using Convolutional Mesh Autoencoders
Learned 3D representations of human faces are useful for computer vision
problems such as 3D face tracking and reconstruction from images, as well as
graphics applications such as character generation and animation. Traditional
models learn a latent representation of a face using linear subspaces or
higher-order tensor generalizations. Due to this linearity, they can not
capture extreme deformations and non-linear expressions. To address this, we
introduce a versatile model that learns a non-linear representation of a face
using spectral convolutions on a mesh surface. We introduce mesh sampling
operations that enable a hierarchical mesh representation that captures
non-linear variations in shape and expression at multiple scales within the
model. In a variational setting, our model samples diverse realistic 3D faces
from a multivariate Gaussian distribution. Our training data consists of 20,466
meshes of extreme expressions captured over 12 different subjects. Despite
limited training data, our trained model outperforms state-of-the-art face
models with 50% lower reconstruction error, while using 75% fewer parameters.
We also show that, replacing the expression space of an existing
state-of-the-art face model with our autoencoder, achieves a lower
reconstruction error. Our data, model and code are available at
http://github.com/anuragranj/com
Talent management and developing leadership talent
An important aspect of talent management in the contemporary organization is the investment and development of leaders including leadership development. Developing leadership talent is viewed as a key lever in delivering competitive advantage in business today. Leadership can be viewed from multiple perspectives: as a personality with special traits or characteristics; an act or behavior shown by the leader; the capability, knowledge, and skills demonstrated by the leader; the process used by the leader to bring groups together; or transformative change and the power relationship that exists between leaders and followers. In essence, developing leadership talent is a multi-layered process, ideally involving a blended learning approach that incorporates formal, informal, and experiential learning. The development of the leader as an individual focuses on building and enhancing the individual's capability to undertake the role of a leader. A key aspect of leader development is that “it is ultimately about facilitating an identity transition” to create new leadership options
Employee engagement in managing environmental performance: a case study of the Planet Champion initiative, McDonald's UK and Sweden
Evidence on education to career transitions in the financial and accountancy sector
The aim of this pilot project was three-fold: 1) create a learning intervention with the aim of developing priority employability skills for first year undergraduate students as determined within the financial services and accountancy sector; 2) explore the participants’ experience of the programme content; 3) identify recommendations for future schemes. The United Kingdom (UK) Financial and Legal Skills Partnership (FLSP) developed a platform to provide mentoring and skills development across financial services and accountancy. Known as “Get In Get On” (GIGO), the FLSP’S virtual work experience comprises two discreet though interdependent features: 1) skills and knowledge development; 2) e-career mentoring. Between February 2014 and April 2014, twenty eight mentees and mentors (from Middlesex University and supportive organisations/individuals) participated in the scheme. The pilot evaluation suggests that there is reciprocal learning for students and professional mentors within the context of the accounting and finance profession. Students have benefitted from a heighted awareness of the career opportunities available in the sector and how their studies may assist them in developing their key employability attributes. Feedback suggests that the scheme has greatest benefit for students entering higher education, with a view to preparing them for future employment
Two-dimensional Induced Ferromagnetism
Magnetic properties of materials confined to nanometer length scales are
providing important information regarding low dimensional physics. Using
gadolinium based Langmuir-Blodgett films, we demonstrate that two-dimensional
ferromagnetic order can be induced by applying magnetic field along the
in-plane (perpendicular to growth) direction. Field dependent exchange coupling
is evident in the in-plane magnetization data that exhibit absence of
hysteresis loop and show reduction in field required to obtain saturation in
measured moment with decreasing temperature.Comment: 4 pages, 3 postscript figures, corrected paper forma
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