Evolution of the earth pressure coefficient of carbonate sand undergoing varying rate of dissolution

In fluid-saturated granular materials, the physicochemical interaction between pore-fluids and grain minerals alters packing conditions, which in turn leads to stress change deformation and, in extreme cases, even collapse. Chemical weathering, either naturally occurring or induced by human activities, is among such natural processes. This article presents an experimental study illustrating the major effects of chemical weathering on the deformation and stress state of granular materials, emphasising particulate systems entirely made by highly soluble carbonate grains. Laboratory experiments are conducted by subjecting acidic environments to granular assemblies under oedometric condition. The reaction rate is controlled by regulating various testing parameters, such as acid concentration and pore fluid flow rate. Experiments revealed that the lateral earth pressure steadily reduces in some cases, while others exhibit non-monotonic evolution. From a macroscopic standpoint, the rate of the chemical reaction was critical to determine the emergence of either of these trends. Such findings are relevant for any particulate system in which the stress conditions are controlled by multi-physical processes proceeding at different rates, such as waste products within bioreactors, gouge materials within faults and natural deposits subjected to the injection/extraction of reactive fluids.

Phosphating Modification with Metal Ions of Carbon Steel Surface to Improve the Influence of Anticorrosion Properties

The purpose of this research is to investigate the influence of the phosphatizing process with Ni2+, Ce3+, and Ti2+ ions on the properties of the coating to obtain better corrosion protection of the metal. Steel corrosion occurs through physicochemical interaction between the metal and its surrounding environment. This leads to a change in the metal’s physical, mechanical, and optical properties that can cause damage to the functionality of the metal, which in turn may result in accidents or other malfunctions. Carbon steel grade has limited resistance to corrosion, depending on the carbon content and alloying element, the microstructure, and the surrounding environment of the material. This paper present tests that have been carried out on some of the physicochemical properties of protective epoxy and polyurethane coating on carbon steel grade. Coatings represent one of the methods available to protect metal surfaces from corrosion. Coating properties such as thickness, hardness, and adhesion were investigated. The same properties were tested by exposing the sample plates to corrosive conditions of the humid chamber and seawater. Their anticorrosion properties were explored by electrochemical impedance spectroscopy (EIS) techniques under immersion in 3.5 wt.% NaCl solutions as a corrosive medium. Part of the samples prior to application of the coatingwere modified with a phosphate solution containing metal ions: Ni2+, Ce3+, and Ti2+ to further investigate the effects of phosphatization on the properties of the coating. After exposure of the plates to the salt and moist chamber conditions, no traces of corrosion products, cracking or peeling of the coating were found on the surfaces. The adhesion properties were tested by the pull-off adhesion test. It was found that metal/polymer adhesion was satisfied according to EN ISO 4624:2016 and had the same value for all samples. However, a detailed EIS analysis showed a higher resistance of phosphate samples with Ce3+ ions than samples that were phosphated with Ni2+ and Ti2+ ions and those that did not have a sparingly soluble phosphate salt layer.

Grease Lubrication: Formulation Effects on Tribological Performance

Grease lubrication performance prediction is challenging. Only recently that empirical equations to predict grease film thickness for prevailing rolling conditions under fully flooded lubrication taking into account thickener properties and content for low, moderate, and high speeds were developed. At starved lubrication, although new insights about the supply and loss mechanisms that govern film formation have been published, contact replenishment and, consequently, film thickness predictions for long-term operation are still not available. Prediction of components efficiency requires film thickness values and properties, including film’s molecular structure, which makes it even more challenging. When it comes to prevailing sliding conditions, the literature is scarce and most of the knowledge developed for prevailing rolling conditions is not applicable. During the sliding of the contacting bodies, boundary and mixed lubrication regimes are expected. In this situation, the tribological response is primarily defined by grease thickener and additives physicochemical interaction with the surface. This complexity leads many researchers to seek simpler relationships between grease formulation and properties with its performance. This review aims to present the state-of-art on grease lubrication and update some of these relationships.

Optimization and Characterization of Self Nano Emulsifying Drug Delivery System loaded with 18- β Glycerrhetinic acid

The purpose of this study was to prepare, optimize and evaluate self nano emulsifying drug delivery system (SNEDDS) containing 18- β glycerrhetinic acid which enhances the dissolution profile or bioavailability of the drug in comparison to pure suspension of 18- β glycerrhetinic acid.18- β glycerrhetinic acid loaded SNEDDS having geranium oil as oil phase, tween 80 as a surfactant, and dimethyl sulfoxide (DMSO) as co-surfactant were prepared using pseudo ternary phase diagram and Box-Behnken experimental design was used to optimize the different formulations. Optimized formulations were characterized for self-emulsifying time, globule size, zeta potential, and drug release. The mean droplet size and PDI of the optimized formulation were found to be in a variation of 93.42 nm and 0.401 respectively. FTIR data showed no physicochemical interaction between excipients and drug. The encapsulation efficiency of optimised 18- β glycerrhetinic acid SNEDDS was found 80.12±1.52% , % transmittance was found 99.34±0.134% and the viscosity of all the formulations was found 0.8872 cp. Three-dimensional response surface plots and two-dimensional contour plots of the responses across the selected factors were constructed that explained the relationship between the independent and dependent variables. Release kinetics was calculated by using KinetDS3.0. It was concluded that prepared formulations were formulated with approximately desired mean droplet size confirmed by Box- Behnken experimental design as well as properly optimized and characterized.

Design the technological process and equipment using fields and energy flows based on analysis of similarity criteria

It is shown that the use of transfer criteria for analysis of the formation processes of structures and phases significantly reduces the amount of experimental research in the design of technological process and equipment using fields and energy flows. It is proposed to use the ratios proportional to the criteria of heat and mass transfer, physicochemical interaction when controlling energy sources. It is shown that the modeling of the combined electromagnetic and thermomechanical effects in the design of technological process and equipment is based on the criteria of heat and mass transfer, electrical and physicochemical interaction, determines the main technological factors, and relates geometric and physical parameters, as well as mechanical quality parameters with the processing performance.

Physicochemical, Interaction & Topological Descriptors vs. hMAO-A Inhibition of Aplysinopsin Analogs: A Boulevard to the Discovery of Semi-Synthetic Anti-Depression Agents

Background: Neurological disorder, depression is the globally 4th leading cause of chronic disabilities in human beings. Objective: This study aimed to model a 2D-QSAR equation that can facilitate the researchers to design better aplysinopsin analogs with potent hMAO-A inhibition. Methods: Aplysinopsin analogs dataset were subjected to ADME assessment for drug-likeness suitability using StarDrop software before modeled equation. 2D-QSAR equations were generated using VLife MDS 4.6. Dataset was segregated into training and test set using different methodologies, followed by variable selection. Model development was done using principal component regression, partial least square regression, and multiple regression. Results: The dataset has successfully qualified the drug-likeness criteria in ADME simulation, with more than 90% of molecules cleared the ideal conditions including intrinsic solubility, hydrophobicity, CYP3A4 2C9pKi, hERG pIC50, etc. 112 models were developed using multiparametric consideration of methodologies. The best six models were discussed with their extent of significance and prediction capabilities. ALP97 was emerged out as the most significant model out of all, with ~83% of the variance in the training set, the internal predictive ability of ~74% while having the external predictive capability of ~79%. Conclusion: ADME assessment suggested that aplysinopsin analogs are worth investigating. Interaction among the descriptors in a way of summation or multiplication products, are quite influential and yielding significant 2D-QSAR models with good prediction efficiency. This model can be used for the design of a more potent hMAO-A inhibitor having an aplysinopsin scaffold, which can then contribute to the treatment of depression and other neurological disorders.

Capture of Acidic Gases from Flue Gas by Deep Eutectic Solvents

Up to now, many kinds of deep eutectic solvents (DESs) were investigated for the capture of acidic gases from flue gases. In this review, non-functionalized and functionalized DESs, including binary and ternary DESs, for SO2, CO2 and NO capture, are summarized based on the mechanism of absorption, physical interaction or chemical reaction. New strategies for improving the absorption capacity are introduced in this review. For example, a third component can be introduced to form a ternary DES to suppress the increase in viscosity and improve the CO2 absorption capacity. DESs, synthesized with halogen salt hydrogen bond acceptors (HBAs) and functionalized hydrogen bond donors (HBDs), can be used for the absorption of SO2 and NO with high absorption capacities and low viscosities after absorption, due to physicochemical interaction between gases and DESs. Emphasis is given to introducing the absorption capacities of acidic gases in these DESs, the mechanism of the absorption, and the ways to enhance the absorption capacity.

Physicochemical interaction with faecal bacteria in characterisation of beach water quality, Gulf of Guinea, Ghana

Human activities such as industrial and agricultural waste discharges directly in the coastal areas increasingly contribute to pollution in coastal waters of Western Africa. The study employed physicochemical and faecal analysis to understand water pollution along the coast of Ghana. The physicochemical parameter such as temperature, salinity, electrical conductivity, pH, dissolved oxygen concentration, dissolved oxygen saturation, total dissolved solids, and redox potential) were measured in situ while water samples were collected determination of total suspended solids, nutrients, chlorophyll-a, and faecal bacteria. The abundance of total coliforms (4061.6 ± 4159.14 CFU/100 ml water), Escherichia coli, and Enterococcus spp. varied significantly (p < 0.05) among the beaches. The high amount of faecal bacteria suggest microbial contamination, possible ecosystem, and health risks to water resource users. This baseline study provides evidence of coastal water contamination to improve beach water quality standards to ensure safe environmental health.

Physicochemical Interaction Processes in the Carbon (Diamond)–Silicon System

The chemical processes occurring during the interaction of carbon (diamond) with silicon are experimentally investigated. Thermal analysis of the interaction of diamond with silicon is carried out. This made it possible to determine the mechanism of the synthesis of silicon carbide and subsequent reaction sintering of diamond particles based on Turing’s reaction-diffusion process and the formation of a microstructure consisting of triple periodic surfaces of the minimal energy.