Coupling Constant of a Vector Meson with Delta Baryons in the Soft-Wall Ads/QCD Model

Russian Physics Journal - The coupling constant of a vector meson with delta baryons in the AdS/QCD model is investigated. A pseudoscalar field is introduced inside the anti-de Sitter (AdS) space...     

Deuteron electromagnetic form factors and tensor polarization observables in the framework of the hard-wall AdS/QCD model

We study the electromagnetic form factors and tensor polarization observables of the deuteron in the framework of the hard-wall AdS/QCD model. We find a profile function for the bulk twist \begin{document}$\tau=6$\end{document} vector field, which describes the deuteron on the boundary and fix the infrared boundary cut-off of AdS space in accordance with the ground state mass of the deuteron. We obtain the deuteron charge monopole, quadrupole, and magnetic dipole form factors and tensor polarization observables from the bulk Lagrangians for the deuteron and photon field interactions. We plot the momentum transfer dependence of the form factors and tensor polarization observables and compare our numerical results with those in the soft-wall model and experimental data.     

Dissociation Behavior of <Emphasis Type="SmallCaps">l</Emphasis>(+)-Lactic Acid in Aqueous Solutions of (1-Alkyl-4-methylpyridinium bromide + Poly (ethyleneglycol)) at <Emphasis Type="Italic">T</Emphasis> = (288.15–318.15) K

The effect of 1-alkyl-4-methylpyridinium based ionic liquids on the conductivity behavior of l(+)-lactic acid (LaH) was studied in Poly(ethylene glycol) (PEG) aqueous solutions. The molar conductivities of LaH in the aqueous solutions of PEG, (PEG + 1-hexyl-4-methylpyridinium bromide) and (PEG + 1-octyl-4-methylpyridinium bromide) were measured over the temperature ranges of 288.15–318.15 K. The molar conductivity data were analyzed by applying the Quint–Viallard (QV) conductivity equation to determine the limiting molar conductivities (Λ ⁰) and dissociation constants (\( K_{\text{D}} \)). The results show that the values of limiting molar conductivity increased as the temperature increased, which indicates that the dissociation process is endothermic. The \( K_{\text{D}} \) values were also used to calculate the dissociation standard thermodynamic functions (\( \Delta G_{\text{D}}^{0} \), \( \Delta S_{\text{D}}^{0} \) and \( \Delta H_{\text{D}}^{0} \)). The results revealed that the dissociation process of LaH is controlled by entropy at all temperatures.     

Axial Vector-Meson–Nucleon Interaction Constant in the AdS/QCD Soft Wall Model

Russian Physics Journal - This work investigates the interaction of an axial vector-meson with nucleons in the AdS/QCD soft wall model. The axial vector fields have been determined inside the...     

Nucleon’s Axial-Vector Form Factor in the Hard-Wall AdS/QCD Model

The axial-vector form factor of the nucleons is considered in the framework of hard-wall model of holographic QCD. A new interaction term between the bulk gauge and matter fields was included into the interaction Lagrangian. We obtain the axial-vector form factor of nucleons in the boundary QCD from the bulk action using AdS/CFT correspondence. The momentum square dependence of the axial-vector form factor is analysed numerically.     

Flow structure, heat transfer and pressure drop in varying aspect ratio two-pass rectangular smooth channels

Two-pass channels are used for internal cooling in a number of engineering systems e.g., gas turbines. Fluid travelling through the curved path, experiences pressure and centrifugal forces, that result in pressure driven secondary motion. This motion helps in moving the cold high momentum fluid from the channel core to the side walls and plays a significant role in the heat transfer in the channel bend and outlet pass. The present study investigates using Computational Fluid Dynamics (CFD), the flow structure, heat transfer enhancement and pressure drop in a smooth channel with varying aspect ratio channel at different divider-to-tip wall distances. Numerical simulations are performed in two-pass smooth channel with aspect ratio W_in/H = 1:3 at inlet pass and W_out/H = 1:1 at outlet pass for a variety of divider-to-tip wall distances. The results show that with a decrease in aspect ratio of inlet pass of the channel, pressure loss decreases. The divider-to-tip wall distance (W_el) not only influences the pressure drop, but also the heat transfer enhancement at the bend and outlet pass. With an increase in the divider-to-tip wall distance, the areas of enhanced heat transfer shifts from side walls of outlet pass towards the inlet pass. To compromise between heat transfer and pressure drop in the channel, W_el/H = 0.88 is found to be optimum for the channel under study.     

Development of high performance nano-porous polyethersulfone ultrafiltration membranes with hydrophilic surface and superior antifouling properties

Hydrophilic nano-porous polyethersulfone ultrafiltration membranes were developed for milk concentration. The membranes were prepared from new dope solution containing polyethersulfone (PES)/polyvinylpirrolidone (PVP)/polyethyleneglycole (PEG)/cellulose acetate phthalate (CAP)/acrylic acid/Triton X-100 using phase inversion induced by immersion precipitation technique. This casting solution leads to formation of new hydrophilic membranes. The morphological studies were investigated by scanning electron microscopy (SEM) and atomic force microscopy (AFM). In addition, the hydrophilicity and performance of membranes were examined by contact angel measurements and cross-flow filtration (pure water flux, milk water permeation, protein rejection and antifouling measurements). The contact angle measurements indicate that a surface with superior hydrophilicity was obtained for PES membranes. Two concentrations of PES (16 and 14.4 wt.%) and two different non-solvents (pure water and mixtures of water and IPA) were used for preparation of membranes. The morphological studies showed that the higher concentration of PES and the presence of IPA in the gelation media results in formation of a membrane with a dense top and sub-layer with small pores on the surface. The pure water flux of membranes was decreased when higher polymer concentration and mixtures of water and IPA were employed for membrane formation. On the other hand, the milk water permeation and protein rejection were increased using mixtures of water and IPA as non-solvent. Furthermore, the fouling analysis of the membranes demonstrated that the membrane surface with fewer tendencies for fouling was obtained.     

Thermoelectrical properties of In1‐xGaxAs and InAs crystals irradiated with fast electrons

The thermoelectric power in In_1‐xGa_xAs (x = 0,01;0,04) solid solutions and InAs crystals irradiated with fast electrons by the energy of 6 MeV and dose of 10¹⁶‐ 2 x 10¹⁷ el/cm^‐2 on the interval 80‐400 K have been investigated. It is revealed that in the all crystals the value of the thermoelectric power is decreased under irradiation that resulted from the growth of the free electron concentration to form radiation induced defects of the donor type. It has been determined that in the initial InAs after irradiation, the charge carriers scatter on optical phonons and in In_1‐xGa_xAs solid solutions they do on optical phonons and ionized impurities. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)