Recent Innovations in Chemical Engineering (Formerly Recent Patents on Chemical Engineering) - Volume 15, Issue 4, 2022

Aim: The present study aimed to optimise the formulation of Olanzapine (OZ)-loaded liquid lamellar phase by using Response Surface Methodology (RSM). Background: In this study, poly (2-ethyl-2-oxazoline) (PEOZ) was selected to modify liquid lamellar phases. The OZ was released from the phases mainly through swelling and diffusion-controlled mechanism simultaneously. Objective: Additionally, two types of mathematical models, based on the lumped and diffusion approaches, were presented for the diffusional release of OZ from the liquid lamellar phases, the second of which was solved with an analytical solution. The controlled release profiles of the models were compared with the in vitro experimental release profiles. Methods: Further, the Box-Behnken experimental design was employed to design the liquid lamellar phase with the three factors, including the weight ratio of water/GMO (w/w) (X1) and PEOZ/GMO (w/w) (X2), and the percentage of OZ (X3). The liquid lamellar phases were prepared based on the top-down method, followed by fragmentation by sonication. Furthermore, the diffusion coefficients of the liquid lamellar phases were calculated, and the effects of variables were evaluated on particle size and diffusion coefficient, as well as the constant of the lumped model. Results: The results revealed an increase in particle size following an enhancement in water level in the liquid lamellar phases, as well as less aggregation with the addition of PEOZ. Conclusion: The generated model was validated by comparing the experimental data and predicted model values graphically, the results of which represented compatibility between the lumped model and experimental data.

Background: The objects of this work are silicon prismanes - new highenergy materials that can be used in various electronic, optoelectronic, thermoelectric, and biological fields and compete with traditional chemical energy carriers. However, only compounds with hexasilacubane and octasilacubane have been synthesized to date. Synthesis of other silapismanes, and even more so polysilaprismanes, has not yet been achieved. Therefore, both the “simplest” and the highest silaprismanes are studied mainly theoretically, including by quantum chemistry methods. Objective and Methods: To expand information about the enthalpies of formation of "simple" (n = 2) and multilayer (n = 3-7) silicon prismanes using semiempirical calculation methods; bond lengths Si-Si and Si-H; compare them with the results of ab initio calculations already available in the literature. Results: The geometry was optimized by semiempirical methods, the enthalpies of formation, Si-Si and Si-H bond lengths, and the bond angles of the bilayer (m = 3-12) and some multilayer (n = 3-8 and m = 3-9) silaprismanes were determined. Comparison with the enthalpies of formation obtained using ab initio calculations shows that the enthalpies of formation obtained by the MINDO/3 method (Modified Intermediate Neglect of Differential Overlap, version 3) are closest to the results of ab initio calculations of two-layer silicon prismanes; and for multilayers - by the AM1 method (Austin Model 1). Large differences in the lengths of Si-H bonds determined ab initio and semi-empirically by both methods are not observed. As for the Si-Si bonds, the results of semi-empirical methods indicate the presence of the so-called auxetic effect in multilayer silaprismanes. Conclusion: We believe that in the future, the calculations carried out in this work and a comparative assessment of the enthalpies of formation obtained by calculation methods will help to overcome the problems associated with the synthesis of silicon prismanes.

Background: The polymer electrolyte membrane serves as a separator and electrolyte in an energy storage device. The structural properties of the host polymer electrolyte have a significant impact on the conductivity value. Objective: The purpose of this study is to investigate the effect of amorphousness and intermolecular interaction degrees between LiClO4 and PLA on the conductivity performance of prepared PLA- based polymer electrolyte film. Methods: The polymer electrolyte film of LiClO4-complexed PLA was prepared with various weight percentages of LiClO4 salt (10%, 20%, 30%, 40%, 50%, and 60%) in PLA by using a solution casting technique. Results: PLA with 50% LiClO4 had the highest degree of amorphousness and the highest percentage of interacting carbonyl groups, which resulted in the highest conductivity of 2.56 x 10^-5 S cm^-1. Conclusion: Finally, the optimum composition of LiClO4 for the amorphousness, interaction of carbonyl group and conductivity are obtained, which can be used for further research to improve the conductivity value to apply it into energy storage devices’ development.

Background: Flow in an annulus between two concentric cylinders or pipes is very often observed, ranging its applications in many streams, namely, in steam generators, condensers, petroleum science and engineering, and various flow devices in chemical processing industries. The objective is to prove or understand the essence of parameters like heat transfer coefficient, mass transfer coefficient, etc., depending on such flow regimes. One such piece of equipment found in industry is a heat exchanger, where heat transfer occurs from one medium to another. Objective: The present study majorly discusses increasing the heat transfer coefficient in the case of shell and tube heat exchangers with rotation of tubes and is restricted to a single tube inside a shell. Methods: The methodology section can be broadly divided into two categories. First, the theoretical solution (obtained under certain assumptions) of the flow between two concentric cylinders, which includes both the rotation case and no rotation case. And second, ANSYS Fluent simulations have been presented at a steady state for both cases. All required conditions, dimensions of the chosen geometry, and assumptions have been clearly mentioned before getting into the discussion or along the way. Moreover, this study is a kind of comparative study between the conventional method of operating and rotation of tubes inside the shell and tube heat exchangers. Results: The results were positive from both the ways – theoretical and ANSYS, that there was a certain increase in the heat transfer coefficient. The overall heat transfer coefficient increased at varying flow rates (0.25 kg/s, 0.5 kg/s, and 1 kg/s) at different speeds of rotation (100 RPM, 200 RPM, and 300 RPM). Conclusion: One of the most common equipment in industries is heat exchanger. Parameters like heat transfer coefficient can be increased by rotating tube(s) of heat exchanger. This was presented using two approaches- analytical and simulation techniques. On varying RPM from 0 to 300, heat transfer coefficient increased by 69.1% for 1 kg/s, 124.7% for 0.5 kg/s, and 172.3% for 0.25 kg/s.

Background: Suspensions can be frequently seen in natural, industrial, and agricultural processes. The addition of dispersed phases (such as solid particles, droplets, and bubbles) greatly affects the rheological properties of matrix liquid. Therefore, it is very important to understand the rheological properties of particle suspensions for optimizing production processes and improving process efficiencies. Objective: To explore qualitatively the physical law and internal mechanism of the apparent viscosity of suspensions formed by a Newtonian liquid containing solid particles, droplets, and bubbles, respectively. Methods: The apparent viscosity of suspensions was measured and analyzed using a rotary rheometer (MCR302), and the evolution of particles was recorded using a highspeed camera (Revealer 2F01M). Results: When the deformation of deformable particles (such as bubbles or water droplets) is slight (close to a sphere in shape), or the arrangement of rigid particles is disordered, the relative viscosity of suspensions is greater than 1. When the deformation of deformable particles is large (greatly deviating from a sphere in shape) or rigid particles are arranged in order, the apparent viscosity of suspensions decreases and the relative viscosity of suspensions containing deformable particles is less than 1. Conclusion: The apparent viscosity of suspensions is closely related to particle shape, particle arrangement, and volume fraction. The higher volume fraction of particles significantly influences the apparent viscosity of suspensions.