Dispersion in doublet-type flows through highly anisotropic porous formations

Steady doublet-type flow takes place in a porous formation, where the log-transform $Y = \ln K$ of the spatially variable hydraulic conductivity $K$ is regarded as a stationary random field of two-point autocorrelation $\rho _Y$ . A passive solute is injected at the source in the porous formation and we aim to quantify the resulting dispersion process between the two lines by means of spatial moments. The latter depend on the distance $\ell$ between the lines, the variance $\sigma ^2_Y$ of $Y$ and the (anisotropy) ratio $\lambda$ between the vertical and the horizontal integral scales of $Y$ . A simple (analytical) solution to this difficult problem is obtained by adopting a few simplifying assumptions: (i) a perturbative solution, which regards $\sigma ^2_Y$ as a small parameter, of the velocity field is sought; (ii) pore-scale dispersion is neglected; and (iii) we deal with a highly anisotropic formation ( $\lambda \lesssim 0.1$ ). We focus on the longitudinal spatial moment, as it is of most importance for the dispersion mechanism. A general expression is derived in terms of a single quadrature, which can be straightforwardly carried out once the shape of $\rho _Y$ is specified. Results permit one to grasp the main features of the dispersion processes as well as to assess the difference with similar mechanisms observed in other non-uniform flows. In particular, the dispersion in a doublet-type flow is observed to be larger than that generated by a single line. This effect is explained by noting that the advective velocity in a doublet, unlike that in source/line flows, is rapidly increasing in the far field owing to the presence there of the singularity. From the standpoint of the applications, it is shown that the solution pertaining to $\lambda \to 0$ (stratified formation) provides an upper bound for the dispersion mechanism. Such a bound can be used as a conservative limit when, in a remediation procedure, one has to select the strength as well as the distance $\ell$ of the doublet. Finally, the present study lends itself as a valuable tool for aquifer tests and to validate more involved numerical codes accounting for complex boundary conditions.

The Influence of Monomer Structure on the Properties of Ionogels Obtained by Thiol–Ene Photopolymerization

The influence of ene and thiol monomer structure on the mechanical and electrochemical properties of thiol–ene polymeric ionogels were investigated. Ionogels were obtained in situ by thiol–ene photopolymerization of 1,3,5-triallyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione (TATT), 2,4,6-triallyloxy-1,3,5-triazine (TAT), diallyl phthalate (DAP), and glyoxal bis(diallyl acetal) (GBDA) used as enes and trimethylolpropane tris(3-mercaptopropionate) (TMPTP), pentaerythritol tetrakis(3-mercaptopropionate) (PETMP), and pentaerythritol tetrakis(3-mercaptobutyrate) (PETMB) used as thiols in 70 wt.% of ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMImNTf2). The mechanical strength of ionogels was studied by puncture resistance and ionic conductivity by electrochemical impedance spectroscopy. The course of photopolymerization by photo-DSC method (differential scanning calorimetry) as well as characterization of compositions and its components (by IR and UV spectroscopy-Kamlet–Taft parameters) were also studied. The resulting ionogels were opaque, with phase separation, which resulted from the dispersion mechanism of polymerization. The mechanical and conductive properties of the obtained materials were found to be largely dependent on the monomer structure. Ionogels based on triazine monomers TAT and TATT were characterized by higher mechanical strength, while those based on aliphatic GBDA had the highest conductivity. These parameters are strongly related to the structure of the polymer matrix, which is in the form of connected spheres. The conductivity of ionogels was high, in the range of 3.5–5.1 mS∙cm−1.

Enhancement of Solubility and Dissolution Rate of BCS Class-II Fluvoxamine Tablets using Solvent Evaporation Solid Dispersion Technique

Aim: This research work was aimed to formulate Enhancing the solubility of Poorly soluble drug i.e. Fluvoxamine tablets by the solvent evaporation method, Fluvoxamine medicament is a selective serotonin reuptake inhibitor (SSRI) antidepressant agent. Purpose: The BCS class II drug Fluvoxamine consist low aqueous solubility and low oral bioavailability, for this reason to improve the biological performance of Fluvoxamine drug by solid dispersion mechanism. Methodolgy: The drug Fluvoxamine was formulated by using solvent evaporation technique, solid dispersions of Fluvoxamine were prepared with different carriers in different ratios of PEG 6000 & Mannitol (1:1, 1:2 and 1:3). Results: Results of prepared solid dispersions of Fluvoxamine by solid dispersion method Finally by comparing all the formulations, formulation (SF3) containing Fluvoxamine and PEG 6000 (1:3) shows better results. Conclusion: Here we concluded that the poorly soluble drug solubility improving by solvent evaporation solid dispersion mechanism, and also developed six Fluvovamine formulations (FDF1-FDF6) during this FDF4 shows maximum (98.9±0.8%) drug release at the end of time.

Patternable Quantum-Dot Photoresist with High Photolithographic Uniformity

We present a ligand-exchange-free photo-patternable quantum-dot photoresist (QDPR) with high photolithographic uniformity. The dispersion mechanism between the QD’s surface ligands and the functional groups of photoresist polymers are studied. Results show that the dispersibility and photoluminescent intensity of this QDPR can be both improved by controlling dispersant and antioxidant. For device demonstration, multi-colored quantum dot color conversion films (QDCCF) were prepared and patterned by a photolithography process. High QD dispersibility and film-forming uniformity were both achieved with this QDCCF. It is believed that the proposed QDPR has the potential to be extensively used in lighting or display applications.