Numerical determination of concrete crack width for corrosion-affected concrete structures

Corrosion-induced deterioration of reinforced concrete (RC) structures results in premature failure of the RC structures. In practice concrete crack width is one of the most important criteria for the assessment of the serviceability of RC structures. It is therefore desirable to predict the growth of the crack width over time so that better informed decisions can be made concerning the repairs due to concrete cracking. Literature review shows that little research has been undertaken on numerical prediction of concrete crack width. The intention of this study was to develop a numerical method to predict concrete crack width for corrosion-affected concrete structures. A cohesive crack model for concrete is implemented in the numerical formulation to simulate crack initiation and propagation in concrete. Choices for evaluating the parameters of cohesive elements are extensively discussed which is a key for developing a plausible model employing cohesive elements. The surface crack width is obtained as a function of service time. Accurate prediction of crack width can allow timely maintenance which prolongs the service life of the reinforced concrete structures

Synergistic therapeutic effect of arsenic trioxide and radiotherapy in BALB/C nude mice bearing nasopharyngeal carcinoma xenografts

It has been shown that arsenic trioxide (ATO) induced apoptosis in human nasopharyngeal carcinoma cells and inhibited the growth of nasopharyngeal carcinoma xenografts (NPCX) in nude mice. Aim: The present study was designed to determine whether ATO at the non-toxic dose level could potentiate the therapeutic effectiveness of radiation therapy in nasopharyngeal carcinoma, using a BALB/C nude mouse xenograft model. Methods: The mice bearing NPCX were treated with radiation alone (2, 4, and 6 Gy), ATO alone (4 mg/kg/day x 6 days), and ATO plus radiation at the same dosage levels. Time of tumor growth delay (defined as the time necessary for the tumor to grow four-fold of its initial volume after, compared with untreated tumors) and toxic effects were determined. Results: The low dose ATO alone has no pronounced effects on tumor growth delay compared to untreated control. However, compared with radiation alone, the combined regimen delayed the tumor growth by 2–10 days and had no significant toxic effects such as the liver function damage. Conclusions: Combination of ATO at non-toxic dose level and radiation has synergistic effects on tumor growth inhibition in vivo and is well tolerated.Установлено, что триоксид мышьяка (ТОМ) индуцирует апоптоз в клетках карциномы носоглотки человека и ингибирует рост ксенографта карциномы носоглотки у атимических мышей. Цель работы — установить терапевтическую эффективность радиотерапии в комбинации ТОМ в нетоксичной дозе мышам линии BALB/ с ксенографтом карциномы носоглотки. Методы: животные с ксенографтом карциномы носоглотки получали либо только радиотерапию (2, 4 и 6 Гр) или ТОМ (4 мг/кг/день в течение 6 дней), или их комбинацию в тех же режимах и дозах. Задержку роста опухоли определяли как различие во времени, необходимом для достижения опухолью 4-кратного объема по сравнению с начальным объемом в опытной группе versus такового в контрольной группе. Результаты: введение ТОМ в низкой дозе не оказывало выраженного влияния на рост опухоли по сравнению с показателями в конт­рольной группе, а в комбинации с облучением приводило к задержке роста опухоли на 2–12 сут по сравнению с показателями у животных, получавших только лучевую терапию при отсутствии выраженных побочных эффектов. Выводы: комбинация ТОМ в нетоксической дозе и лучевой терапии приводит к ингибированию роста опухоли in vivo и не вызывает побочных эффектов. Ключевые слова: триоксид мышьяка, радиотерапия, ксенографт карциномы носоглотки

Simulating EGFR-ERK signaling control by scaffold proteins KSR and MP1 reveals differential Ligand-Sensitivity Co-Regulated by CBL-CIN85 and Endophilin

10.1371/journal.pone.0022933PLoS ONE68

BES3 time of flight monitoring system

A Time of Flight monitoring system has been developed for BES3. The light source is a 442-443 nm laser diode, which is stable and provides a pulse width as narrow as 50 ps and a peak power as large as 2.6 W. Two optical-fiber bundles with a total of 512 optical fibers, including spares, are used to distribute the light pulses to the Time of Flight counters. The design, operation, and performance of the system are described.Comment: 8 pages 16 figures, submitted to NI

Multiple superconducting gap and anisotropic spin fluctuations in iron arsenides: Comparison with nickel analog

We present extensive 75As NMR and NQR data on the superconducting arsenides PrFeAs0.89F0.11 (Tc=45 K), LaFeAsO0.92F0.08 (Tc=27 K), LiFeAs (Tc = 17 K) and Ba0.72K0.28Fe2As2 (Tc = 31.5 K) single crystal, and compare with the nickel analog LaNiAsO0.9F0.1 (Tc=4.0 K) . In contrast to LaNiAsO0.9F0.1 where the superconducting gap is shown to be isotropic, the spin lattice relaxation rate 1/T1 in the Fe-arsenides decreases below Tc with no coherence peak and shows a step-wise variation at low temperatures. The Knight shift decreases below Tc and shows a step-wise T variation as well. These results indicate spinsinglet superconductivity with multiple gaps in the Fe-arsenides. The Fe antiferromagnetic spin fluctuations are anisotropic and weaker compared to underdoped copper-oxides or cobalt-oxide superconductors, while there is no significant electron correlations in LaNiAsO0.9F0.1. We will discuss the implications of these results and highlight the importance of the Fermi surface topology.Comment: 6 pages, 11 figure

Optical properties and radiative forcing of urban aerosols in Nanjing, China

AbstractContinuous measurements of atmospheric aerosols were made in Nanjing, a megacity in China, from 18 January to 18 April, 2011 (Phase 1) and from 22 April 2011 to 21 April 2012 (Phase 2). Aerosol characteristics, optical properties, and direct radiative forcing (DRF) were studied through interpretations of these measurements. We found that during Phase 1, mean PM2.5, black carbon (BC), and aerosol scattering coefficient (Bsp) in Nanjing were 76.1 ± 59.3 μg m−3, 4.1 ± 2.2 μg m−3, and 170.9 ± 105.8 M m−1, respectively. High pollution episodes occurred during Spring and Lantern Festivals when hourly PM2.5 concentrations reached 440 μg m−3, possibly due to significant discharge of fireworks. Temporal variations of PM2.5, BC, and Bsp were similar to each other. It is estimated that inorganic scattering aerosols account for about 49 ± 8.6% of total aerosols while BC only accounted for 6.6 ± 2.9%, and nitrate was larger than sulfate. In Phase 2, optical properties of aerosols show great seasonality. High relative humidity (RH) in summer (June, July, August) likely attributed to large optical depth (AOD) and small Angstrom exponent (AE) of aerosols. Due to dust storms, AE of total aerosols was the smallest in spring (March, April, May). Annual mean 550-nm AOD and 675/440-nm AE were 0.6 ± 0.3 and 1.25 ± 0.29 for total aerosols, 0.04 ± 0.02 and 1.44 ± 0.50 for absorbing aerosols, 0.48 ± 0.29 and 1.64 ± 0.29 for fine aerosols, respectively. Annual single scattering albedo of aerosols ranged from 0.90 to 0.92. Real time wavelength-dependent surface albedo from the Moderate Resolution Imaging Spectroradiometer (MODIS) was used to assess aerosol DRFs. Both total and absorbing aerosol DRFs had significant seasonal variations in Nanjing and they were the strongest in summer. Annual mean clear sky TOA DRF (including daytime and nighttime) of total and absorbing aerosols was about −6.9 and +4.5 W m−2, respectively. Aerosol DRFs were found to be sensitive to surface albedo. Over brighter surfaces, solar radiation was more absorbed by absorbing aerosols and less scattered by scattering aerosols

Phonon Hall effect in ionic crystals in the presence of static magnetic field

We study phonon Hall effect (PHE) for ionic crystals in the presence of static magnetic field. Using Green-Kubo formula, we present an exact calculation of thermal conductivity tensor by considering both positive and negative frequency phonons. Numerical results are shown for some lattices such as hexagonal lattices, triangular lattices, and square lattices. We find that the PHE occurs on the nonmagnetic ionic crystal NaCl, although the magnitude is very small which is due to the tiny charge-to-mass ratio of the ions. The off-diagonal thermal conductivity is finite for nonzero magnetic field and changes sign for high value of magnetic field at high temperature. We also found that the off-diagonal thermal conductivity diverges as $\pm{1/T}$ at low temperature

Generalized second law of thermodynamics in f(T) gravity

We investigate the validity of the generalized second law (GSL) of gravitational thermodynamics in the framework of f(T) modified teleparallel gravity. We consider a spatially flat FRW universe containing only the pressureless matter. The boundary of the universe is assumed to be enclosed by the Hubble horizon. For two viable f(T) models containing $f(T)=T+\mu_1{(-T)}^n$ and $f(T)=T-\mu_2 T(1-e^{\beta\frac{T_0}{T}})$, we first calculate the effective equation of state and deceleration parameters. Then, we investigate the null and strong energy conditions and conclude that a sudden future singularity appears in both models. Furthermore, using a cosmographic analysis we check the viability of two models. Finally, we examine the validity of the GSL and find that for both models it is satisfied from the early times to the present epoch. But in the future, the GSL is violated for the special ranges of the torsion scalar T.Comment: 16 pages, 10 figures, accepted by JCAP 201