A Second Order Characteristic Method for Approximating Incompressible Miscible Displacement in Porous Media

An approximation scheme is defined for incompressible miscible displacement in porous media. This scheme is constructed by two methods. Under the regularity assumption for the pressure, cubic Hermite finite element method is used for the pressure equation, which ensures the approximation of the velocity smooth enough. A second order characteristic finite element method is presented to handle the material derivative term of the concentration equation. It is of second order accuracy in time increment, symmetric, and unconditionally stable. The optimal L2-norm error estimates are derived for the scalar concentration

Corrigendum to “Modeling Inhibitory Effect on the Growth of Uninfected T Cells Caused by Infected T Cells: Stability and Hopf Bifurcation”

We consider a class of viral infection dynamic models with inhibitory effect on the growth of uninfected T cells caused by infected T cells and logistic target cell growth. The basic reproduction number R0 is derived. It is shown that the infection-free equilibrium is globally asymptotically stable if R0<1. Sufficient conditions for the existence of Hopf bifurcation at the infected equilibrium are investigated by analyzing the distribution of eigenvalues. Furthermore, the properties of Hopf bifurcation are determined by the normal form theory and the center manifold. Numerical simulations are carried out to support the theoretical analysis

Modeling Inhibitory Effect on the Growth of Uninfected T Cells Caused by Infected T Cells: Stability and Hopf Bifurcation

We consider a class of viral infection dynamic models with inhibitory effect on the growth of uninfected T cells caused by infected T cells and logistic target cell growth. The basic reproduction number R0 is derived. It is shown that the infection-free equilibrium is globally asymptotically stable if R0<1. Sufficient conditions for the existence of Hopf bifurcation at the infected equilibrium are investigated by analyzing the distribution of eigenvalues. Furthermore, the properties of Hopf bifurcation are determined by the normal form theory and the center manifold. Numerical simulations are carried out to support the theoretical analysis

Research on hydrogen fuel cell backup power for metal hydride hydrogen storage system

Hydrogen fuel cells are characterized by non-pollution, high efficiency and long power supply time, and they are increasingly used as backup power systems in substations, communication base stations and other fields. In this paper, based on the thermodynamic model of the hydride hydrogen storage system, the relationship between pressure, composition, and temperature in metal hydride hydrogen storage is quantitatively analyzed using a PCT curve. The hydrogen fuel power supply is used as the overall backup power supply of the DC system, and the hydrogen-fuel integrated backup power supply is established to realize the uninterrupted switching between the utility power and the backup power supply. Finally, the working process of the backup power supply and the reaction process of hydrogen are analyzed to test the feasibility of a hydrogen fuel cell backup power supply. The results show that the operating current climbs to the end of 80 A under the 5 kW workload demand of the communication equipment. In addition, the hydrogen absorption reaction rate was 0.29 Mpa, and the hydrogen release reaction rate was 0.21 Mpa at a temperature of 291 K. This study has developed a fuel cell backup power system that can provide uninterruptible backup power and has a wide market capacity and application prospects

Effect of Gluten and Wheat Starch on the Frozen Storage Quality of Reconstituted Dough

The frozen preservation quality of dough cannot meet the requirements of industrial production of fresh and wet noodles. To investigate the effect of the main dough components (gluten protein and starch) on the quality of the frozen dough, dough restructuring with high gluten wheat flour (50%) and different proportions of gluten and wheat starch, and the water distribution, rheological properties, pasting characteristics, gel strength, microstructure and hydrogen bond strength were analyzed after freezing storage at 18 ℃ for 20 days, with 100% raw wheat flour as the control group. The results showed that the water in the frozen reconstituted dough gradually migrated from bound water to free water, and the elastic modulus decreased from 125900 Pa to 73020 Pa as the ratio of gluten to wheat starch decreased from 4:1 to 1:4, the pasting parameters increased, andgel hardness from 114.30 g to 181.39 g. Scanning electron microscope showed that the lower the ratio of gluten to wheat starch, the more unfavorable the uniformity of the gluten protein network structure. The hydrogen bond strength in the reconstituted dough was greater than that in the control group after adding gluten and wheat starch, and it continued to increase as the ratio of gluten to wheat starch decreased. When the ratio of gluten to wheat starch was 4:1, the elastic modulus of the reconstituted dough frozen for 20 days was 49.95% higher than that of the control group, which delayed the quality deterioration of the dough during the frozen storage. Reconstituting the dough with a certain ratio of starch to gluten can improve the viscoelasticity of the dough, which was beneficial to its cryopreservation quality

Mo2C as Non-Noble Metal Co-Catalyst in Mo2C/CdS Composite for Enhanced Photocatalytic H-2 Evolution under Visible Light Irradiation

Co-catalysts are a major factor to enhance photocatalytic H-2 activity; they are mainly composed of expensive noble metals. Here, we reported a new non-noble-metal co-catalyst Mo2C that efficiently improves the photocatalytic H-2 evolution of CdS under visible light irradiation. Mo2C is prepared by temperature-programmed reaction with molybdenum oxide as precursor, and the Mo2C/CdS composite is prepared by deposition of CdS on Mo2C. The optimum composite 2.0% Mo2C/CdS shows a high H-2 evolution rate of 161 mu mol h(-1), which is tentimes higher than that of CdS alone and 2.3 times higher than the optimum for 1.0% Pt/CdS. Moreover, the Mo2C/CdS is stable for 50 h. This study presents a new low-cost non-noble-metal co-catalyst as a photocatalyst to achieve highly efficient H-2 evolution

Zearalenone Induces Apoptosis and Cytoprotective Autophagy in Chicken Granulosa Cells by PI3K-AKT-mTOR and MAPK Signaling Pathways

Zearalenone (ZEA) is a nonsteroidal estrogenic mycotoxin found in several food commodities worldwide. ZEA causes reproductive disorders, genotoxicity, and testicular toxicity in animals. However, little is known about the functions of apoptosis and autophagy after exposure to ZEA in granulosa cells. This study investigated the effects of ZEA on chicken granulosa cells. The results show that ZEA at different doses significantly inhibited the growth of chicken granulosa cells by inducing apoptosis. ZEA treatment up-regulated Bax and downregulated Bcl-2 expression, promoted cytochrome c release into the cytosol, and triggered mitochondria-mediated apoptosis. Consequently, caspase-9 and downstream effector caspase-3 were activated, resulting in chicken granulosa cells apoptosis. ZEA treatment also upregulated LC3-II and Beclin-1 expression, suggesting that ZEA induced a high level of autophagy. Pretreatment with chloroquine (an autophagy inhibitor) and rapamycin (an autophagy inducer) increased and decreased the rate of apoptosis, respectively, in contrast with other ZEA-treated groups. Autophagy delayed apoptosis in the ZEA-treated cells. Therefore, autophagy may prevent cells from undergoing apoptosis by reducing ZEA-induced cytotoxicity. In addition, our results further show that the autophagy was stimulated by ZEA through PI3K-AKT-mTOR and MAPK signaling pathways in chicken granulosa cells