612 research outputs found
Nonuniversal Effects in the Homogeneous Bose Gas
Effective field theory predicts that the leading nonuniversal effects in the
homogeneous Bose gas arise from the effective range for S-wave scattering and
from an effective three-body contact interaction. We calculate the leading
nonuniversal contributions to the energy density and condensate fraction and
compare the predictions with results from diffusion Monte Carlo calculations by
Giorgini, Boronat, and Casulleras. We give a crude determination of the
strength of the three-body contact interaction for various model potentials.
Accurate determinations could be obtained from diffusion Monte Carlo
calculations of the energy density with higher statistics.Comment: 24 pages, RevTex, 5 ps figures, included with epsf.te
An application of hybrid life cycle assessment as a decision support framework for green supply chains
In an effort to achieve sustainable operations, green supply chain management has become an important area for firms to concentrate on due to its inherent involvement with all the processes that provide foundations to successful business. Modelling methodologies of product supply chain environmental assessment are usually guided by the principles of life cycle assessment (LCA). However, a review of the extant literature suggests that LCA techniques suffer from a wide range of limitations that prevent a wider application in real-world contexts; hence, they need to be incorporated within decision support frameworks to aid environmental sustainability strategies. Thus, this paper contributes in understanding and overcoming the dichotomy between LCA model development and the emerging practical implementation to inform carbon emissions mitigation strategies within supply chains. Therefore, the paper provides both theoretical insights and a practical application to inform the process of adopting a decision support framework based on a LCA methodology in a real-world scenario. The supply chain of a product from the steel industry is considered to evaluate its environmental impact and carbon âhotspotsâ. The study helps understanding how operational strategies geared towards environmental sustainability can be informed using knowledge and information generated from supply chain environmental assessments, and for highlighting inherent challenges in this process
Out-of-Plane Magnetic Anisotropy in Ordered Ensembles of FeN Nanocrystals Embedded in GaN
Phase-separated semiconductors containing magnetic nanostructures are
relevant systems for the realization of high-density recording media. Here, the
controlled strain engineering of GaFeN layers with FeN embedded
nanocrystals (NCs) \textit{via} AlGaN buffers with different Al
concentration \% is presented. Through the addition of Al
to the buffer, the formation of predominantly prolate-shaped
-FeN NCs takes place. Already at an Al concentration
\,\,5\% the structural properties---phase, shape,
orientation---as well as the spatial distribution of the embedded NCs are
modified in comparison to those grown on a GaN buffer. Although the magnetic
easy axis of the cubic '-GaFeN nanocrystals in the layer on
the buffer lies in-plane, the easy axis of the
-FeN NCs in all samples with AlGaN buffers
coincides with the growth direction, leading to a sizeable
out-of-plane magnetic anisotropy and opening wide perspectives for
perpendicular recording based on nitride-based magnetic nanocrystals.Comment: 29 pages, 10 figures, submitte
Coexistence of Anomalous Hall Effect and Weak Net Magnetization in Collinear Antiferromagnet MnTe
Anomalous Hall effect (AHE) plays important role in the rapidly developing
field of antiferromagnetic spintronics. It has been recently discussed that it
can be a feature of not only uncompensated magnetic systems but also in
altermagnetic materials. Hexagonal MnTe belongs to this appealing group of
compounds exhibiting AHE and is commonly perceived as magnetically compensated.
Here, we demonstrate that bulk form of MnTe exhibits small but detectable
magnetic moment correlating with hysteretic behaviour of the AHE. We formulate
a phenomenological model which explains how this feature allows to create a
disbalance between states with opposite N\'eel vector and prevent the AHE
signal from averaging out to zero. Moreover, we show how the dependence of AHE
on the N\'eel vector arises on microscopical level and highlight the
differences in Berry curvature between magnetically compensated and
uncompensated systems
Application of short time energy analysis in monitoring the stability of arc sound signal
This paper employed the short time energy of arc sound signals to online quantitatively describe the stability of arc sound signal. At first the signal can be preprocessed by wavelet packet filtering and then detailed information of the short time energy of the signal was obtained using hamming window. After statistical analyzed the short time energy the energy distribution possibility and cumulative distribution function of the signal can be collected. Then a proposed stability evaluation criterion was employed to quantitatively describe the stability of arc sound signal. Relative experimental data showed that more stable signal corresponded lager value of the criterion. The proposed method which combined the short time energy and statistical analysis was supported by many actual experiments. This contribution can benefit the quantitative evaluation of the arc welding process and instructed the future parameters optimization to obtain welding products with high quality. (C) 2017 Elsevier Ltd. All rights reserved
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