10,634 research outputs found
Greening Supply Chains in China: Practical Lessons From China-Based Suppliers in Achieving Environmental Performance
Presents case studies of how five China-based suppliers are meeting international buyers' environmental requirements. Examines management processes; effective low-cost ways to reduce water pollution; and the roles of multistakeholders and third parties
Effects of vibrational excitation on the F + H2O → HF + OH reaction: dissociative photodetachment of overtone-excited [F-H-OH].
The reaction F + H2O → HF + OH is a four-atom system that provides an important benchmark for reaction dynamics. Hydrogen atom transfer at the transition state for this reaction is expected to exhibit a strong dependence on reactant vibrational excitation. In the present study, the vibrational effects are examined by photodetachment of vibrationally excited F-(H2O) precursor anions using photoelectron-photofragment coincidence (PPC) spectroscopy and compared with full six-dimensional quantum dynamical calculations on ab initio potential energy surfaces. Prior to photodetachment at hνUV = 4.80 eV, the overtone of the ionic hydrogen bond mode in the precursor F-(H2O), 2νIHB at 2885 cm-1, was excited using a tunable IR laser. Experiment and theory show that vibrational energy in the anion can be effectively carried away by the photoelectron upon a Franck-Condon photodetachment, and also show evidence for an increase of branching into the F + H2O reactant channel. The experimental results suggest a greater role for product rotational excitation than theory. Improved potential energy surfaces and longer wavepacket propagation times would be helpful to further examine the nature of the discrepancy
Investigating IoT Middleware Platforms for Smart Application Development
With the growing number of Internet of Things (IoT) devices, the data
generated through these devices is also increasing. By 2030, it is been
predicted that the number of IoT devices will exceed the number of human beings
on earth. This gives rise to the requirement of middleware platform that can
manage IoT devices, intelligently store and process gigantic data generated for
building smart applications such as Smart Cities, Smart Healthcare, Smart
Industry, and others. At present, market is overwhelming with the number of IoT
middleware platforms with specific features. This raises one of the most
serious and least discussed challenge for application developer to choose
suitable platform for their application development. Across the literature,
very little attempt is done in classifying or comparing IoT middleware
platforms for the applications. This paper categorizes IoT platforms into four
categories namely-publicly traded, open source, developer friendly and
end-to-end connectivity. Some of the popular middleware platforms in each
category are investigated based on general IoT architecture. Comparison of IoT
middleware platforms in each category, based on basic, sensing, communication
and application development features is presented. This study can be useful for
IoT application developers to select the most appropriate platform according to
their application requirement
Neutron/proton ratio of nucleon emissions as a probe of neutron skin
The dependence between neutron-to-proton yield ratio () and neutron
skin thickness () in neutron-rich projectile induced reactions is
investigated within the framework of the Isospin-Dependent Quantum Molecular
Dynamics (IQMD) model. The density distribution of the Droplet model is
embedded in the initialization of the neutron and proton densities in the
present IQMD model. By adjusting the diffuseness parameter of neutron density
in the Droplet model for the projectile, the relationship between the neutron
skin thickness and the corresponding in the collisions is obtained.
The results show strong linear correlation between and
for neutron-rich Ca and Ni isotopes. It is suggested that may be used
as an experimental observable to extract for neutron-rich nuclei,
which is very significant to the study of the nuclear structure of exotic
nuclei and the equation of state (EOS) of asymmetric nuclear matter.Comment: 7 pages, 5 figures; accepted by Phys. Lett.
Mechanical control of the directional stepping dynamics of the kinesin motor
Among the multiple steps constituting the kinesin's mechanochemical cycle,
one of the most interesting events is observed when kinesins move an 8-nm step
from one microtubule (MT)-binding site to another. The stepping motion that
occurs within a relatively short time scale (~100 microsec) is, however, beyond
the resolution of current experiments, therefore a basic understanding to the
real-time dynamics within the 8-nm step is still lacking. For instance, the
rate of power stroke (or conformational change), that leads to the
undocked-to-docked transition of neck-linker, is not known, and the existence
of a substep during the 8-nm step still remains a controversial issue in the
kinesin community. By using explicit structures of the kinesin dimer and the MT
consisting of 13 protofilaments (PFs), we study the stepping dynamics with
varying rates of power stroke (kp). We estimate that 1/kp <~ 20 microsec to
avoid a substep in an averaged time trace. For a slow power stroke with 1/kp>20
microsec, the averaged time trace shows a substep that implies the existence of
a transient intermediate, which is reminiscent of a recent single molecule
experiment at high resolution. We identify the intermediate as a conformation
in which the tethered head is trapped in the sideway binding site of the
neighboring PF. We also find a partial unfolding (cracking) of the binding
motifs occurring at the transition state ensemble along the pathways prior to
binding between the kinesin and MT.Comment: 26 pages, 10 figure
On the scattering of longitudinal elastic waves from axisymmetric defects in coated pipes
This is the post-print version of the final paper published in Journal of Sound and Vibration. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2013 Elsevier B.V.Viscoelastic coatings are widely used to protect pipelines from their surrounding environment. These coatings are known to attenuate ultrasonic waves guided along the pipe walls, which may limit the range of a pulse/echo based inspection technique that seeks to detect defects in a pipeline. This article aims to investigate the attenuation of longitudinal modes in a coated pipe by comparing predicted and measured values for the reflection coefficient of an axisymmetric defect in a pipe coated with bitumen. This extends recent work undertaken by the authors for torsional modes, and also provides an independent investigation into the validity of those values proposed by the authors for the shear properties of bitumen, based on a comparison between prediction and experiment for torsional modes. Predictions are generated using a numerical mode matching approach for axially uniform defects, and a hybrid finite element based method for non-uniform defects. Values for the shear and longitudinal properties of bitumen are investigated and it is shown that the shear properties of the viscoelastic material play a dominant role in the propagation of longitudinal modes in a coated pipeline. Moreover, by using the shear values obtained from experiments on torsional modes, it is shown that good agreement between prediction and measurement for uniform and non-uniform defects may also be obtained for the longitudinal L(0,2) mode. This provides further validation for the shear bulk acoustic properties proposed for bitumen in the low ultrasonic frequency range, although in order to apply this methodology in general it is demonstrated that one must measure independently the reflection coefficient of both the torsional T(0,1) and the longitudinal L(0,2) mode before arriving at values for the shear properties of a viscoelastic material
Moment Analysis and Zipf Law
The moment analysis method and nuclear Zipf's law of fragment size
distributions are reviewed to study nuclear disassembly. In this report, we
present a compilation of both theoretical and experimental studies on moment
analysis and Zipf law performed so far. The relationship of both methods to a
possible critical behavior or phase transition of nuclear disassembly is
discussed. In addition, scaled factorial moments and intermittency are
reviewed.Comment: Caption of Fig.6 was corrected. Review paper for WCI (World Consensus
Initiative) Book "Dynamics and Thermodynamics with Nuclear Degrees of
Freedom", published in Euorpean Physics Journal A as part of the Topical
Volume. 16 pages, 21 figure
A Modified TreePM Code
We discuss the performance characteristics of using the modification of the
tree code suggested by Barnes \citep{1990JCoPh..87..161B} in the context of the
TreePM code. The optimisation involves identifying groups of particles and
using only one tree walk to compute force for all the particles in the group.
This modification has been in use in our implementation of the TreePM code for
some time, and has also been used by others in codes that make use of tree
structures. In this paper, we present the first detailed study of the
performance characteristics of this optimisation. We show that the
modification, if tuned properly can speed up the TreePM code by a significant
amount. We also combine this modification with the use of individual time steps
and indicate how to combine these two schemes in an optimal fashion. We find
that the combination is at least a factor of two faster than the modified
TreePM without individual time steps. Overall performance is often faster by a
larger factor, as the scheme of groups optimises use of cache for large
simulations.Comment: 16 pages, 5 figures; Accepted for publication in Research In
Astronomy and Astrophysics (RAA
Study on Sedation with Local Analgesia in Calves
. The effect of sedatives and analgesics on heart rate, respiration rate and rectal temperature were observed. Heart rate and respiration rate significantly decreased during sedation with xylazine hydrochloride plus 2% lignocaine hydrochloride or 0.5% bupivacaine hydrochloride. A significantly decreased heart rate and respiration rate also found during sedation with diazepam plus 2% lignocaine hydrochloride or 0.5% bupivacaine hydrochloride. Two percent lignocaine hydrochloride showed short onset, rapid spreading and no side effect. Duration of analgesia was longer with 0.5 % bupivacaine hydrochloride (55.88±1.58 min in Group B and 48±11.25 min in Group D) compared to 2% lignocaine hydrochloride (39.60±5.77 min in Group A and 43.6±5.81 min in Group C). Xylazine hydrochloride showed short onset and long duration of sedation compared to diazepam. So for herniorraphy, xylazine hydrochloride can be used as a better sedative while 0.5 % bupivacaine hydrochloride can be used as a local analgesic for longer duration of action
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