Evaluation of multi-phase heat transfer and droplet evaporation in petroleum cracking flows

A computer code ICRKFLO was used to simulate the multiphase reacting flow of fluidized catalytic cracking (FCC) riser reactors. The simulation provided a fundamental understanding of the hydrodynamics and heat transfer processes in an FCC riser reactor, critical to the development of a new high performance unit. The code was able to make predictions that are in good agreement with available pilot-scale test data. Computational results indicate that the heat transfer and droplet evaporation processes have a significant impact on the performance of a pilot-scale FCC unit. The impact could become even greater on scale-up units

Pressure dependence of the superconducting transition temperature of the filled skutterudite YFe4P12

We have studied the pressure dependence of the superconducting transition temperature Tc of the filled skutterudite YFe4P12 under various quasihydrostatic pressures up to 8 GPa. DC magnetization measurements up to 1.2 GPa in a piston-cylinder cell yields a linear increase of Tc with a positive coefficient dTc/dP = 1 K/GPa. Resistivity measurements up to 8 GPa in a cubic anvil apparatus show that Tc increases to 9.3 K at 8 GPa, but the slope decreases gradually with increasing pressure. Besides the previously reported LaFe4P12, YFe4P12 becomes the second filled skutterudite superconductor that exhibits a positive pressure coefficient dTc/dP in a broad pressure range. The observed large dTc/dP > 0 of YFe4P12 can be rationalized by our band-structure calculations that show an enhancement of density of states at Fermi energy and the Hopfield parameter under pressure at least up to 8 GPa. On the other hand, similar calculations predict a dTc/dP < 0 for YRu4P12

[Accepted Manuscript] Seasonal variations of temperature-related mortality burden from cardiovascular disease and myocardial infarction in China.

Incidence rate of cardiovascular disease (CVD) has significant seasonal trend, being higher in winter. However, the extent to which the seasonal variation of CVD deaths was caused by temperature remains unclear. We obtained daily data on temperature and CVD and myocardial infarction (MI) mortality from nine Chinese mega-cities during 2007-2013. Distributed lag non-linear models were applied to assess the city-specific temperature-related daily excess deaths across lag 0-21 days, using the minimum-mortality temperature as reference. Then, estimates of excess deaths in four seasons were separately aggregated from the daily series, and its ratio to the corresponding total deaths produced seasonal attributable fraction (AF). In total, 1,079,622 CVD and 201,897 MI deaths were recorded in the nine Chinese cities. Significant and non-linear associations between temperature and mortality were observed, with a total of 195,516 CVD and 50,658 MI deaths attributable to non-optimum temperatures. 103,439 (95% empirical CI: 54,475-141,537) CVD and 24,613 (5891-36,279) MI deaths related to non-optimum temperature occurred in winter, compared with 15,923 (1436-28,853) and 4946 (-325-9016) in summer. Temperature-related AFs were higher among MI than CVD, with AFs of 42% (9-62%) and 35% (19-48%) in winter, and 13% (-1-23%) and 8% (1-14%) in summer, respectively. This study may have important implications for developing effective targeted intervention measures on CVD events

The ARGO-YBJ Experiment Progresses and Future Extension

Gamma ray source detection above 30TeV is an encouraging approach for finding galactic cosmic ray origins. All sky survey for gamma ray sources using wide field of view detector is essential for population accumulation for various types of sources above 100GeV. To target the goals, the ARGO-YBJ experiment has been established. Significant progresses have been made in the experiment. A large air shower detector array in an area of 1km2 is proposed to boost the sensitivity. Hybrid detection with multi-techniques will allow a good discrimination between different types of primary particles, including photons and protons, thus enable an energy spectrum measurement for individual specie. Fluorescence light detector array will extend the spectrum measurement above 100PeV where the second knee is located. An energy scale determined by balloon experiments at 10TeV will be propagated to ultra high energy cosmic ray experiments

Charm multiplicity and the branching ratios of inclusive charmless b quark decays in the general two-Higgs-doublet models

In the framework of general two-Higgs-doublet models, we calculate the branching ratios of various inclusive charmless b decays by using the low energy effective Hamiltonian including next-to-leading order QCD corrections, and examine the current status and the new physics effects on the determination of the charm multiplicity $n_c$ and semileptonic branching ratio $B_{SL}$. Within the considered parameter space, the enhancement to the ratio $BR(b \to s g)$ due to the charged-Higgs penguins can be as large as a factor of 8 (3) in the model III (II), while the ratio $BR(b \to no charm)$ can be increased from the standard model prediction of 2.49% to 4.91% (2.99%) in the model III (II). Consequently, the value of $B_{SL}$ and $n_c$ can be decreased simultaneously in the model III. The central value of $B_{SL}$ will be lowered slightly by about 0.003, but the ratio $n_c$ can be reduced significantly from the theoretical prediction of $n_c= 1.28 \pm 0.05$ in the SM to $n_c= 1.23 \pm 0.05$, $1.18 \pm 0.05$ for $m_{H^+}=200, 100$ GeV, respectively. We find that the predicted $n_c$ and the measured $n_c$ now agree within roughly one standard deviation after taking into account the effects of gluonic charged Higgs penguins in the model III with a relatively light charged Higgs boson.Comment: 25 pages, Latex file, axodraw.sty, 6 figures. Final version to be published in Phys.Rev.

Measurement of the Atmospheric Muon Spectrum from 20 to 3000 GeV

The absolute muon flux between 20 GeV and 3000 GeV is measured with the L3 magnetic muon spectrometer for zenith angles ranging from 0 degree to 58 degree. Due to the large exposure of about 150 m2 sr d, and the excellent momentum resolution of the L3 muon chambers, a precision of 2.3 % at 150 GeV in the vertical direction is achieved. The ratio of positive to negative muons is studied between 20 GeV and 500 GeV, and the average vertical muon charge ratio is found to be 1.285 +- 0.003 (stat.) +- 0.019 (syst.).Comment: Total 32 pages, 9Figure

Generalized Second Law of Thermodynamics in f(T)f(T) Gravity with Entropy Corrections

We study the generalized second law (GSL) of thermodynamics in $f(T)$ cosmology. We consider the universe as a closed bounded system filled with $n$ component fluids in the thermal equilibrium with the cosmological boundary. We use two different cosmic horizons: the future event horizon and the apparent horizon. We show the conditions under which the GSL will be valid in specific scenarios of the quintessence and the phantom energy dominated eras. Further we associate two different entropies with the cosmological horizons: with a logarithmic correction term and a power-law correction term. We also find the conditions for the GSL to be satisfied or violated by imposing constraints on model parameters.Comment: 17 pages, no figure, title changed, version accepted for publication in Astrophysics and Space Scienc

ARGO-YBJ constraints on very high energy emission from GRBs

The ARGO-YBJ (Astrophysical Radiation Ground-based Observatory at YangBaJing) experiment is designed for very high energy $\gamma$-astronomy and cosmic ray researches. Due to the full coverage of a large area ($5600 m^2$) with resistive plate chambers at a very high altitude (4300 m a.s.l.), the ARGO-YBJ detector is used to search for transient phenomena, such as Gamma-ray bursts (GRBs). Because the ARGO-YBJ detector has a large field of view ($\sim$2 sr) and is operated with a high duty cycle ($>$90%), it is well suited for GRB surveying and can be operated in searches for high energy GRBs following alarms set by satellite-borne observations at lower energies. In this paper, the sensitivity of the ARGO-YBJ detector for GRB detection is estimated. Upper limits to fluence with 99% confidence level for 26 GRBs inside the field of view from June 2006 to January 2009 are set in the two energy ranges 10$-$100 GeV and 10 GeV$-$1 TeV.Comment: accepted for publication in Astroparticle Physic