12,371 research outputs found
Radiation Measurements and Data Analysis of Turbulent Premixed Lean Flame
An accurate understanding of the radiation transfer in turbulent premixed lean flame is critical for improving energy efficiencies and reducing emissions such as nitric oxide and soot. Radiation measurement is an effective and nonintrusive way to study the radiation properties of turbulent premixed lean flames. In this study, a high-speed infrared camera was utilized to measure the planar radiation from turbulent premixed lean flames under different conditions. Time-dependent flame images were acquired and radiation statistics were calculated and compared to investigate the effects of equivalence ratio, heat release rate, hydrogen pilot flame rate, and co-flow rate on the radiation intensity of the flames. Results show that radiation intensity increases with equivalence ratio and heat release rate. However, changes of hydrogen pilot flame rate and co-flow rate have little impact on the radiation intensity. These experimental data are essential for the study of turbulent premixed lean flames and the calibration of the empirical relations in the simulation models
Quantitative Test of SO(5) Symmetry in the Vortex State of
By numerically solving models with competing superconducting and
antiferromagnetic orders, we study the magnetic field dependence of the
antiferromagnetic moment in both the weak and strong field regimes. Through a
omparison with the neutron scattering results of Kang et al and Matsuura et
al.on , we conclude that this system is close to a
SO(5) symmetric critical point. We also make a quantitative prediction on
increasing the upper critical field and the superconducting transition
temperature by applying an in-plane magnetic field.Comment: 4 pages, 3 figures v3: final version PRL 92, 107002 (2004
Self-consistency of optimizing finite-time Carnot engines with the low-dissipation model
The efficiency at the maximum power (EMP) for finite-time Carnot engines
established with the low-dissipation model, relies significantly on the
assumption of the inverse proportion scaling of the irreversible entropy
generation on the operation time , i.e.,
. The optimal operation time of the
finite-time isothermal process for EMP has to be within the valid regime of the
inverse proportion scaling. Yet, such consistency was not tested due to the
unknown coefficient of the -scaling. In this paper, using a two-level
atomic heat engine as an illustration, we reveal that the optimization of the
finite-time Carnot engines with the low-dissipation model is self-consistent
only in the regime of , where is the
Carnot efficiency. In the large- regime, the operation time
for EMP obtained with the low-dissipation model is not within the valid regime
of the -scaling, and the exact EMP is found to surpass the well-known
bound Comment: 6 pages, 4 figures, Comments are welcom
A Second Method to Photometrically Align Multi-Site Microlensing Light Curves: Source Color in Planetary Event MOA-2007-BLG-192
At present, microlensing light curves from different telescopes and filters
are photometrically aligned by fitting them to a common model. We present a
second method based on photometry of common field stars. If two spectral
responses are similar (or the color of the source is known) then this technique
can resolve important ambiguities that frequently arise when predicting the
future course of the event, and that occasionally persist even when the event
is over. Or if the spectral responses are different, it can be used to derive
the color of the source when that is unknown. We present the essential elements
of this technique and apply it to the case of MOA-2007-BLG-192, an important
planetary event for which the system may be a terrestrial planet orbiting a
brown dwarf or very low mass star. The refined estimate of the source color
that we derive here, V-I=2.36 +- 0.03, will aid in making the estimate of the
lens mass more precise.Comment: 16 pages including 3 figures. Submitted to Ap
Pb Neurotoxicity: Neuropsychological Effects of Lead Toxicity
Neurotoxicity is a term used to describe neurophysiological changes caused by exposure to toxic agents. Such exposure can result in neurocognitive symptoms and/or psychiatric disturbances. Common toxic agents include heavy metals, drugs, organophosphates, bacterial, and animal neurotoxins. Among heavy metal exposures, lead exposure is one of the most common exposures that can lead to significant neuropsychological and functional decline in humans. In this review, neurotoxic lead exposure\u27s pathophysiology, etiology, and epidemiology are explored. In addition, commonly associated neuropsychological difficulties in intelligence, memory, executive functioning, attention, processing speed, language, visuospatial skills, motor skills, and affect/mood are explored
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Metabolic syndrome does not affect sustained virologic response of direct-acting antivirals while hepatitis C clearance improves hemoglobin A1c.
AimTo determine whether successful treatment with directacting antivirals (DAA) is associated with improvements in hemoglobin A1c (HbA1c) and if type 2 diabetes mellitus (T2DM) or metabolic syndrome affects sustained virologic response (SVR).MethodsWe performed a retrospective analysis of all hepatitis C virus (HCV) patients at the VA Greater Los Angeles Healthcare System treated with varying DAA therapy between 2014-2016. Separate multivariable logistic regression was performed to determine predictors of HbA1c decrease ≥ 0.5 after DAA treatment and predictors of SVR 12-wk post treatment (SVR12).ResultsA total of 1068 patients were treated with DAA therapy between 2014-2016. The presence of T2DM or metabolic syndrome did not adversely affect SVR12. 106 patients had both HCV and T2DM. Within that cohort, patients who achieved SVR12 had lower mean HbA1c pre treatment (7.35 vs 8.60, P = 0.02), and lower mean HbA1c post-treatment compared to non-responders (6.55 vs 8.61, P = 0.01). The mean reduction in HbA1c after treatment was greater for those who achieved SVR12 than for non-responders (0.79 vs 0.01, P = 0.03). In adjusted models, patients that achieved SVR12 were more likely to have a HbA1c decrease of ≥ 0.5 than those that did not achieve SVR12 (adjusted OR = 7.24, 95%CI: 1.22-42.94).ConclusionIn HCV patients with T2DM, successful treatment with DAA was associated with a significant reduction in HbA1c suggesting that DAA may have a role in improving insulin sensitivity. Furthermore, the presence of T2DM or metabolic syndrome does not adversely affect SVR12 rates in patients treated with DAA
Signature of Spin Collective Mode in Local Tunneling Spectra of a d-wave Superconductor
We consider the influence of magnetic excitations on the local density of
states in the d-wave superconductor. The magnetic susceptibility is calculated
within the renormalized model and its influence on the quasiparticle
self-energy is considered using a minimal model originally proposed by
Polkovnikov {\it et al.}[cond-mat/0203176]. We find the local density of states
possess periodic components both along and directions
with the associated wavevectors changing in magnitude as the quasiparticle
energy is varied. Comparison with the STM experiment reveals that the
calculated LDOS modulation is inconsistent with the measured data.Comment: Two figures separately attached as .jpg file
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