Chlorido(dimethyl sulfoxide-κO)triphenyl­tin(IV)

In the title compound, [Sn(C6H5)3Cl(C2H6OS)], the SnIV atom is coordinated by three phenyl groups, a chloride ion and a dimethyl sulfoxide mol­ecule in a distorted trigonal-bipyramidal geometry. In the crystal, adjacent mol­ecules are linked through inter­molecular C—H⋯Cl hydrogen bonds, weak C—H⋯π inter­actions and π–π inter­actions [centroid–centroid distance = 3.934 (3) Å. An intra­molecular C—H⋯π inter­action is also observed

Some Summation Theorems for Clausen’s Hypergeometric Functions with Unit Argument

Motivated by the work on hypergeometric summation theorems, we establish new summation formula for Clausen’s hypergeometric function with unit argument in terms of pi and natural logarithms of some rational and irrational numbers. For the application purpose, we derive some new and modified summation theorems for Clausen’s hypergeometric functions using our new formula

Roles and functions of special purpose vehicles (SPV): a comparison between Islamic and conventional finance / Mohammad Soleimani and S. Mustafa Shadab

The SPV (special purpose vehicle) is one of the key components of the securitization in both Islamic and conventional finance; however the details of how the transactions are implemented differ subject to the mode of securitization in Islamic and conventional finance. In conventional finance, the bank establishes a SPV and transfers its asset from its balance sheet to the SPV. The assets are used as the collateral for issuing securitized, debt-like instruments. Nevertheless, in Islamic finance mode of securitization, the SPV just services the cash flows for security holders and do participate in debt-issuance. This difference is originated from the risk-sharing principle in asset-based Islamic finance which contrasts with risk-transfer nature of an interest-based conventional finance and results in important differences in ownership right and valuation of SPVs in the two financial systems

A hyperbolic-elliptic PDE model and conservative numerical method for gravity-dominated variably-saturated groundwater flow

Richards equation is often used to represent two-phase fluid flow in an unsaturated porous medium when one phase is much heavier and more viscous than the other. However, it cannot describe the fully saturated flow due to degeneracy in the capillary pressure term. Mathematically, gravity-driven variably saturated flows are interesting because their governing partial differential equation switches from hyperbolic in the unsaturated region to elliptic in the saturated region. Moreover, the presence of wetting fronts introduces strong spatial gradients often leading to numerical instability. In this work, we develop a robust, multidimensional mathematical and computational model for such variably saturated flow in the limit of negligible capillary forces. The elliptic problem for saturated regions is built-in efficiently into our framework for a reduced system corresponding to the saturated cells, with the boundary condition of the fixed head at the unsaturated cells. In summary, this coupled hyperbolic-elliptic PDE framework provides an efficient, physics-based extension of the hyperbolic Richards equation to simulate fully saturated regions. Finally, we provide a suite of easy-to-implement yet challenging benchmark test problems involving saturated flows in one and two dimensions. These simple problems, accompanied by their corresponding analytical solutions, can prove to be pivotal for the code verification, model validation (V&V) and performance comparison of such simulators. Our numerical solutions show an excellent comparison with the analytical results for the proposed problems. The last test problem on two-dimensional infiltration in a stratified, heterogeneous soil shows the formation and evolution of multiple disconnected saturated regions.Comment: 21 pages, 9 figure

Dentin bonding agent with improved bond strength to dentin through incorporation of sepiolite nanoparticles

The study aims to investigate the effect of incorporation of sepiolite nanoparticles on the microtensile bond strength of an experimental dentin bonding to the human dentin. The sepiolite nanoparticles were incorporated into an experimental methacrylate-based dentin bonding system in concentrations of 0.0, 0.2, 1.0, 2.0, and 5.0 weight percents. The specimens were then ultrasonicated to finely disperse the nanoparticles in the adhesive matrix. The coronal enamel of 30 intact human premolars was cut to expose dentin. Having etched, rinsed, and blot dried the experimental bonding agents were applied to dentin surface. Adper Single Bond was used as control group according to the manufactor?s instruction. Then all the teeth were built up by composite and sectioned in stick form for microtensile test. The fracture surface was observed using SEM. The data were analyzed by ANOVA and Tukey?s post-Hoc test. The results indicated that the incorporation of the nanofiller, improved the bond strength to dentin with the highest values obtained at 1 w% sepiolite nanoparticle content. Sepiolite nanoparticles can be considered as novel fillers to improve the mechanical properties of dentin bonding agents

Interfacial and Capillary Pressure Effects on the Thermal Performance of Wax/Foam Composites

A numerical investigation study was performed to study the phase change behavior of wax/foam composite encapsulated in an aluminum casing. Two types of foam materials, namely, aluminum and carbon, were infiltrated with paraffin wax. The progress of melt interface and temperature distribution within the encapsulated composite was analyzed using computational fluid dynamics software (CFD). A two-energy equation model was implemented in the CFD software through the use of user-defined function (UDF). Interfacial effects influencing the heat transfer process at the casing-composite junction and between the wax-foam surfaces within the composite were addressed through the use of separate UDF. In addition, the effect of capillary pressure developed within the foam matrix was incorporated using an area ratio parameter. The contact resistance at the foam-casing interface and the capillary pressure had a major influence on the thermal behavior of the system. These two factors lowered the heat transfer rate considerably, and the melting area was reduced by more than 30%. The temperature profiles for the foam material showed a different pattern as compared to the temperature within the wax, which was due to the effect of thermal nonequilibrium