Modelling temperature dynamics of the SAGD process in an oil reservoir by the discovery of parametric partial differential equations

Many chemical and industrial processes are complex, and the dynamics of such processes cannot be explained using a partial differential equation (PDE) or a system of PDEs with constant coefficients. Parametric PDEs, that is, PDEs with their coefficients varying across time or space, are utilized for this purpose. The non-availability of data at all spatial locations and partially available process knowledge add to the complexity of modelling such processes. This paper proposes a framework to discover parametric PDEs using data-driven and hybrid modelling approaches with the temperature dynamics of steam-assisted gravity drainage (SAGD) process in an oil reservoir as the system under study. We utilize an ensemble of 200 realizations of the temperature dynamics generated using the variogram for the PDE discovery. Permeability, which is one of the oil reservoir's petrophysical properties, is used to develop the hybrid models. We infer that utilizing partial process knowledge aids in improving the model's accuracy.     

Buried Metal Silicon-on-Insulator Junctionless Transistor for Low Power CMOS Logic Circuits

Silicon - This paper deals with an innovative structure of silicon-on-insulator junctionless transistor (SOIJLT) by incorporating a buried metal layer of proper work-function which creates the...     

A Novel Surfactant with Short Hydrophobic Head and Long Hydrophilic Tail Generates Vesicles with Unique Structural Feature

Surfactant molecules typically have a long hydrophobic tail and a short hydrophilic head group. It remains unexplored if surfactants can have a short hydrophobic head group and a long hydrophilic tail. Designing such surfactants is a challenge as a lengthy hydrophilic tail would completely solubilize the molecules. In this context, herein, the Fmoc-functionalized Gly-Pro-Hyp (GPO) tripeptide repeat-based molecule (Fm-GPO) with fluorenyl moiety as a short hydrophobic head and peptide as a long hydrophilic tail is demonstrated as a reverse surfactant at physiological pH, for the first time. π–π stacking of the fluorenyl moieties and intermolecular hydrogen bonding between the peptide chains with extended polyproline-II structure promoted the self-assembly into spherical vesicles with a unique feature of a large hydrophilic area in the interior and exterior of the bilayer. The current Fm-GPO system offers a new class of surfactants with unique features that can aid in the design of drug-loaded vehicles, which can be target-specific as the peptide chain can be manipulated with different functional ultra-short peptide sequences.     

Strategies for Interference of Insulin Fibrillogenesis: Challenges and Advances

The discovery of insulin came with very high hopes for diabetic patients. In 2021, the world celebrated the 100th anniversary of the discovery of this vital hormone. However, external use of insulin is highly affected by its aggregating tendency that occurs during its manufacturing, transportation, and improper handling which ultimately leads to its pharmaceutically and biologically ineffective form. In this review, we aim to discuss the various approaches used for decelerating insulin aggregation which results in the enhancement of its overall structural stability and usage. The approaches that are discussed are broadly classified as either a measure through excipient additions or by intrinsic modifications in the insulin native structure.     

Review on Polymer Materials for Solid Desiccant Cooling System

As an alternative form of vapor compression air conditioning devices, solid desiccant cooling (SDC) techniques have increasingly been explored recently. The overall performances of SDC primarily rely on the capability of dehumidification and regeneration of desiccant. A desiccant with a great uptake capability and excellent regeneration potential is preferred in an SDC system. Although traditional desiccants like silica gels and zeolites are able to absorb moisture at moderate levels, hygroscopic polymers show a superior ability in moisture sorption and desorption. Significant research has been conducted to investigate the hygroscopic polymers in SDC for household and industrial applications. Here, first, an introduction to SDC systems is presented, and then hygroscopic polymers from natural and synthetic origins are discussed. Synthetic polymers discussed are metal–organic frameworks (MOFs), covalent organic frameworks (COFs), covalent triazine frameworks (CTFs), amorphous porous organic polymers (POPs), polyelectrolytes, and polymer-based composites. Their dehumidification behaviors in SDC systems, primarily desiccant-coated heat exchanger (DCHE) systems, are compared and summarized. Binders employed in SDC systems are also summarized, as a proper binder enhances the overall performance of the desiccant system. It can be anticipated that hygroscopic polymers and binder materials would witness extensive applications in the future.     

Comparative study of weld-line strength for unfilled and glass-filled thermoplastic polyamide-6 materials

The injection molding process is widely accepted for the processing of engineering thermoplastics due to the ease of manufacturing complex designs. Weld-line is a defect occurring in injection molded parts when two flow fronts join each other. At weld-line locations, parts exhibit lower mechanical strength mainly due to inadequate intermolecular diffusion and fiber orientation anisotropy. The present work is aimed at investigating and comparing weld-line strength for unfilled and glass-filled polyamide-6 materials. To achieve this, polyamide-6 unfilled, 30% glass-filled, and 50% glass-filled materials are used to manufacture plaques. The special-purpose mold is designed to obtain plaques with and without weld-lines with help of Moldflow simulations. The specimens for tensile tests are then cut from molded plaques and experimental testing is conducted to evaluate tensile properties. Fractured surfaces of specimens are examined using a scanning electron microscope. The results demonstrated a significant drop in tensile strength and modulus for glass-filled material weld-line specimens when compared to specimens of no weld-line. However, for unfilled specimens, tensile strength and modulus are almost the same for samples with and without weld-line. A reduction in tensile strength of 13%, 49%, and 57% is observed for unfilled, 30% glass-filled, and 50% glass-filled polyamide-6 material respectively.