851 research outputs found
Investigation into high-frequency-vibration assisted micro-blanking of pure copper foils
The difficulties encountered during the manufacture of microparts are often associated with size effects relating to material, process and tooling. Utilizing acoustoplastic softening, achieved through a high-frequency vibration assisted micro-blanking process, was introduced to improve the surface finish in micro-blanking. A frequency of 1.0âkHz was chosen to activate the longitudinal vibration mode of the horn tip, using a piezoelectric actuator. A square hole with dimensions of 0.5âmm Ă 0.5âmm was made, successfully, from a commercial rolled T2 copper foil with 100âÎŒm in thickness. It was found that the maximum blanking force could be reduced by 5% through utilizing the high-frequency vibration. Proportion of the smooth, burnished area in the cut cross-section increases with an increase of the plasticity to fracture, under the high-frequency vibration, which suggests that the vibration introduced is helpful for inhibiting evolution of the crack due to its acoustoplastic softening effect. During blanking, roughness of the burnished surface could be reduced by increasing the vibration amplitude of the punch, which played a role as surface polishing. The results obtained suggest that the high-frequency vibration can be adopted in micro-blanking in order to improve quality of the microparts
Comparison of methods to estimate aerosol effective radiative forcings in climate models
Uncertainty in the effective radiative forcing (ERF) of climate primarily arises from the unknown contribution of aerosols, which impact radiative fluxes directly and through modifying cloud properties. Climate model simulations with fixed sea surface temperatures but perturbed atmospheric aerosol loadings allow for an estimate of how strongly the planet's radiative energy budget has been perturbed by the increase in aerosols since pre-industrial times. The approximate partial radiative perturbation (APRP) technique further decomposes the contributions to the direct forcing due to aerosol scattering and absorption and to the indirect forcing due to aerosol-induced changes in cloud scattering, amount, and absorption, as well as the effects of aerosols on surface albedo. Here we evaluate previously published APRP-derived estimates of aerosol effective radiative forcings from these simulations conducted in the sixth phase of the Coupled Model Intercomparison Project (CMIP6) and find that they are biased as a result of two large coding errors that â in most cases â fortuitously compensate. The most notable exception is the direct radiative forcing from absorbing aerosols, which is more than 40â% larger averaged across CMIP6 models in the present study. Correcting these biases eliminates the residuals and leads to better agreement with benchmark estimates derived from double calls to the radiation code. The APRP method â when properly implemented â remains a highly accurate and efficient technique for diagnosing aerosol ERF in cases where double radiation calls are not available, and in all cases it provides quantification of the individual contributors to the ERF that are highly useful but not otherwise available
Tumor necrosis factor superfamily 15 promotes lymphatic metastasis via upregulation of vascular endothelial growth factor-C in a mouse model of lung cancer
Lymphatic metastasis is facilitated by lymphangiogenic growth factor vascular endothelial growth factor-C (VEGFC) that is secreted by some primary tumors. We previously identified tumor necrosis factor superfamily 15 (TNFSF15), a blood vascular endothelium-derived cytokine, in lymphatic endothelial cells, as a key molecular modulator during lymphangiogenesis. However, the effect of TNFSF15 on tumor lymphatic metastasis and the underlying molecular mechanisms remain unclear. We report here that TNFSF15, which is known to inhibit primary tumor growth by suppressing angiogenesis, can promote lymphatic metastasis through facilitating lymphangiogenesis in tumors. Mice bearing tumors induced by A549 cells stably overexpressing TNFSF15 exhibited a significant increase in densities of lymphatic vessels and a marked enhancement of A549 tumor cells in newly formed lymphatic vessels in the primary tumors as well as in lymph nodes. Treatment of A549 cells with TNFSF15 results in upregulation of VEGFC expression, which can be inhibited by siRNA gene silencing of death domain-containing receptor-3 (DR3), a cell surface receptor for TNFSF15. In addition, TNFSF15/DR3 signaling pathways in A549 cells include activation of NF-ÎșB during tumor lymphangiogenesis. Our data indicate that TNFSF15, a cytokine mainly produced by blood endothelial cells, facilitates tumor lymphangiogenesis by upregulating VEGFC expression in A549 cells, contributing to lymphatic metastasis in tumor-bearing mice. This finding also suggests that TNFSF15 may have potential as an indicator for prognosis evaluation.Tingting Qin, Dingzhi Huang, Zhujun Liu, Xiaoling Zhang, Yanan Jia, Cory J. Xian, Kai L
Glueballs, gluon condensate, and pure glue QCD below T_c
A quasiparticle description of pure glue QCD thermodynamics at T<T_c is
proposed and compared to recent lattice data. Given that a gas of glueballs
with constant mass cannot quantitatively reproduce the early stages of the
deconfinement phase transition, the problem is to identify a relevant mechanism
leading to the observed sudden increase of the pressure, trace anomaly, etc. It
is shown that the strong decrease of the gluon condensate near T_c combined
with the increasing thermal width of the lightest glueballs might be the
trigger of the phase transition.Comment: 5 pages, 5 figures; analysis refined in v2, explanations added; v3 to
appear in EPJ
Development of electrospun photocatalytic TiO2-polyamide-12 nanocomposites
Titanium dioxide (TiO2) in different forms such as films, fibers or particles are being extensively studied
for removal of contaminants from aquatic environments due to its outstanding photocatalytic activity.
This work reports the development of TiO2-polyamide 12 electrospun fiber mats. A systematic study on
the influence of electrospun processing parameters on polymer fiber morphology was performed. It was
observed that the average fiber diameter is mainly influenced by polymer concentration and average
fiber diameters between 404 ± 82 nm and 1442 ± 360 nm were obtained. Polyamide-12 (PA-12) was
used as a polymer matrix and electrospun with 0, 10 and 20 wt% of TiO2. It was observed that the filler
does not change the average fiber diameter, being similar to that observed for neat PA-12 fibers processed
under the same experimental conditions. The TiO2 were particles dispensed not only in the bulk
of the polymeric matrix but also on the surface of the fibers, especially for the samples with higher filler
contents. Neat and nanocomposite electrospun samples show a hydrophobic behavior and a degree of
crystallinity of ~25%.
The photocatalytic performance of the processed samples was measured by following the degradation
capability of a chosen dye, methylene blue (MB). Results show that the nanocomposite samples have a
remarkable photocatalytic activity, especially the one with a higher load of TiO2 particles (20 wt%), with
all MB being removed from the solution after 100 min.This work was supported by FEDER through the COMPETE
Program and by the Portuguese Foundation for Science and Technology
(FCT) in the framework of the Strategic Project PEST-C/FIS/
UI607/2014, and CNPq (Conselho Nacional de Desenvolvimento
CientĂfico e Tecnol ogico e Brazil). The authors also thank funding
from âMatepro eOptimizing Materials and Processesâ, ref. NORTE-
07-0124-FEDER-000037â, co-funded by the âPrograma Operacional
Regional do Norteâ (ON.2 e O Novo Norte), under the âQuadro de
Refer^encia Estrat egico Nacionalâ (QREN), through the âFundo
Europeu de Desenvolvimento Regionalâ (FEDER). PM thanks the
FCT for the, SFRH/BD/98616/2013 grant. VS and SLM also thank
support from the COST Action MP1206 âElectrospun Nano-fibers for bio inspired composite materials and innovative industrial applicationsâ.
VS thanks the EIS Faculty at UOW for the starting grant
Functional diversity of chemokines and chemokine receptors in response to viral infection of the central nervous system.
Encounters with neurotropic viruses result in varied outcomes ranging from encephalitis, paralytic poliomyelitis or other serious consequences to relatively benign infection. One of the principal factors that control the outcome of infection is the localized tissue response and subsequent immune response directed against the invading toxic agent. It is the role of the immune system to contain and control the spread of virus infection in the central nervous system (CNS), and paradoxically, this response may also be pathologic. Chemokines are potent proinflammatory molecules whose expression within virally infected tissues is often associated with protection and/or pathology which correlates with migration and accumulation of immune cells. Indeed, studies with a neurotropic murine coronavirus, mouse hepatitis virus (MHV), have provided important insight into the functional roles of chemokines and chemokine receptors in participating in various aspects of host defense as well as disease development within the CNS. This chapter will highlight recent discoveries that have provided insight into the diverse biologic roles of chemokines and their receptors in coordinating immune responses following viral infection of the CNS
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Simulating maize yield in sub-tropical conditions of southern Brazil using Glam model
The objective of this work was to evaluate the feasibility of simulating maize yield in a subâtropical
region of southern Brazil using the general large area model (Glam). A 16âyear time series of daily weather data
were used. The model was adjusted and tested as an alternative for simulating maize yield at small and large
spatial scales. Simulated and observed grain yields were highly correlated (r above 0.8; p<0.01) at large scales
(greater than 100,000 km2), with variable and mostly lower correlations (r from 0.65 to 0.87; p<0.1) at small
spatial scales (lower than 10,000 km2). Large area models can contribute to monitoring or forecasting regional
patterns of variability in maize production in the region, providing a basis for agricultural decision making, and
GlamâMaize is one of the alternatives
\psi(2S) Decays into \J plus Two Photons
Using \gamma \gamma J/\psi, J/\psi \ra e^+ e^- and events
from a sample of \psip decays collected with the BESII
detector, the branching fractions for \psip\ra \pi^0\J, \eta\J, and
\psi(2S)\ar\gamma\chi_{c1},\gamma\chi_{c2}\ar\gamma\gamma\jpsi are measured
to be B(\psip\ra \pi^0\J) = (1.43\pm0.14\pm0.13)\times 10^{-3}, B(\psip\ra
\eta\J) = (2.98\pm0.09\pm0.23)%,
B(\psi(2S)\ar\gamma\chi_{c1}\ar\gamma\gamma\jpsi) = (2.81\pm0.05\pm 0.23)%,
and B(\psi(2S)\ar\gamma\chi_{c2}\ar\gamma\gamma\jpsi) = (1.62\pm0.04\pm
0.12)%.Comment: 7 pages, 6 figures. submitted to Phys. Rev.
Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC
Measurements of inclusive jet suppression in heavy ion collisions at the LHC
provide direct sensitivity to the physics of jet quenching. In a sample of
lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated
luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with
a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the
transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the
anti-kt algorithm with values for the distance parameter that determines the
nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of
the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp.
Jet production is found to be suppressed by approximately a factor of two in
the 10% most central collisions relative to peripheral collisions. Rcp varies
smoothly with centrality as characterized by the number of participating
nucleons. The observed suppression is only weakly dependent on jet radius and
transverse momentum. These results provide the first direct measurement of
inclusive jet suppression in heavy ion collisions and complement previous
measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables,
submitted to Physics Letters B. All figures including auxiliary figures are
available at
http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02
Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment
This paper describes an analysis of the angular distribution of W->enu and
W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with
the ATLAS detector at the LHC in 2010, corresponding to an integrated
luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and
the missing transverse energy, the W decay angular distribution projected onto
the transverse plane is obtained and analysed in terms of helicity fractions
f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV
and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw
> 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour,
are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017
+/- 0.030, where the first uncertainties are statistical, and the second
include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables,
revised author list, matches European Journal of Physics C versio
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