Calculation Of Parameters Research Articles

Influence of quartz types on mechanical parameters in the early silurian Longmaxi shale, Sichuan Basin

Quartz is one of the most abundant minerals in shales, occurring predominantly in three forms: biogenic quartz (BQ), detrital quartz (DQ) and clay-transformed quartz (CTQ). The content of quartz is typically correlated with the fracability of shale gas reservoirs. However, the origins of quartz and its influence on mechanical properties remain not fully elucidated. To address this gap, this study examines shale samples from LM1-LM8 graptolite zones in well W202 of the Weiyuan shale gas field, the Sichuan Basin as the research object. After systematic analysis of organic geochemistry, mineral composition, cathodoluminescence observation, major/trace elements, and log interpretation and calculation of shale mechanical parameters, the genetic mechanism of quartz was analyzed and the percentage of quartz of different origins and the influence on rock mechanical properties were evaluated quantitatively. The results indicate that the three types of quartz (BQ, DQ and CTQ) were variably present in the Longmaxi shale across different graptolite zones. The LM1-LM3 graptolite zones exhibit the highest abundance of BQ, with contents ranging from 58.3 to 79.6%, with an average of 65.7%. DQ predominates in the LM4-LM5 and LM6-LM8 graptolite zones, with average contents of 38.7% and 34.9%, respectively. The BQ content is marginally higher in the LM4-LM5 zone compared to the LM6-LM8 zone, averaging 12.7% and 6.1%, respectively. The three types of quartz exert a dual influence on Young’s modulus, and a single linear effect on Poisson’s ratio. An increase BQ content correlates with a decreased in Poisson’s ratio, whereas increased contents of DQ and CTQ correlate with an increased Poisson’s ratio. With the highest Young’s modulus and the lowest Poisson’s ratio, the LM1-LM3 shale is the most favorable interval for hydraulic fracturing. Furthermore, BQ is positively correlated with the Brittleness index (BI), whereas the contents of DQ and CTQ are negatively correlated with BI. When the quartz content falls between 52% and 85%, the ratio of DQ to BQ is optimal for fracture development coinciding with high BI values, which are most conducive to fracturing stimulation.

Maximum waves in the Black Sea based on the results of numerical modeling

In this paper, a comparison of the wind waves parameters calculations in the Black and Azov seas, using two common spectral wave models: DHI MIKE 21 SW and SWAN was made. The fields of the wind waves main parameters (wave heights, periods, directions of propagation) were obtained for a climatic period of time from 1979 to 2018. Comparison of the calculation results shows that with the accepted model settings, the SWAN model, compared with MIKE, overestimates the values of wave heights with weak and moderate waves and underestimates with the extreme ones. Estimation of the maximum wave heights on the Black Sea, possible once in a given number of years, performed on two different models, was made. It showed that for the conditions of the Black Sea the difference between the calculated values of significant wave heights of rare frequency for the MIKE and SWAN models does not exceed 12%. The maximum significant wave heights, possible once in a hundred years, in the Black Sea can reach 11-12 m.

A novel design approach for structures with inerter systems based on non-stationary seismic excitations

Existing research predominantly focuses on developing design methods for the structural configuration of inerter systems. However, the authors find that these optimization methods often overlook the non-stationary characteristics associated with seismic response. Additionally, traditional approximation algorithms yield significant errors in non-stationary processes, resulting in inaccurate predictions of the structural responses with inerter systems, which compromises the effectiveness of the optimization designs. This paper proposes a novel approach that combines the parameters of the inerter system with a modified Vanmarcke approximation to obtain unified calculation formulas for inerter parameters. The accuracy and computational efficiency in solving spectral moments are crucial for the feasibility of this method. The study presents an efficient calculation method to accurately determine non-stationary response spectral moments of structures with inerter systems. Using the complex modal method (CMM) and pseudo-excitation method (PEM), a unified solution for structural responses under seismic actions is obtained. The quadratic decomposition of the power spectral density function (QD-PSDF) is employed to derive analytical solutions for response spectral moments and non-geometric spectral characteristics (NGSC). Substituting the obtained moment values into the parameter calculation formulas allows effective determination of the inerter system parameters. Finally, Finite Element Method (FEM) modeling verifies the validity and general applicability of this approach. The results demonstrate that the proposed method accounts for non-stationary characteristics of structures with inerter systems under seismic excitations, enhancing seismic design reliability and structural safety. Moreover, the obtained inerter system parameters at each floor effectively achieve the target performance while providing a broader range of design options for enhanced flexibility in system configuration.

A Data-Driven Seismic Fragility Model for Post-Earthquake Repairable Performance of Highway Curved Bridge Portfolios

The rapid assessment of seismic fragility for highway curved bridges is crucial for enhancing the seismic resilience of transportation infrastructure. However, commonly used performance limit states fail to fully capture post-earthquake rehabilitation requirements. To address this, this paper proposes a data-driven, system-level seismic fragility assessment method for post-earthquake repairable performance of highway curved bridge portfolios. A sample database of curved bridge portfolios is generated using uniform design (UD) and a parametric finite element program, which then drives machine learning (ML) algorithms to develop a seismic fragility prediction model for post-earthquake repairable performance. The model is used to analyze the influence of various structural attributes on the median values of fragility curves (mR) for curved bridges. Additionally, a simplified fragility estimation method is developed based on the analysis results, and its reliability is validated through typical case studies. The results show that the central discrepancy of the UD sampling method is 0.0649, providing reliable and comprehensive data support for the ML prediction model. The fragility prediction model based on an artificial neural network (ANN) exhibits favorable fidelity and robustness. Curved bridges with central angles (α) in the range of 00.5rad show significant variations in mR, with a coupling effect observed between α and column height (H). The median absolute percentage error (MAPE) of the simplified fragility parameter calculation formula is below 11%, offering a preliminary reference for assessing the post-earthquake repairable performance of curved bridges.

Comparison of Optical Properties in Single-Shade and Multi-Shade Composite Resins

This study aimed to evaluate the differences in optical properties, such as color and translucency, between single-shade composite resins (Omnichroma) and multi-shade composite resins (Filtek Z350XT). Furthermore, the study assessed the influence of the surrounding structure’s shades on the shade matching of Omnichroma. Two types of disc-shaped specimens were prepared: Single specimen (diameter, 8.0 mm; thickness, 1.0 and 2.0 mm), consisting of either Omnichroma or Filtek Z350XT in the A1B, A2B, and A3B shades, and dual specimen (diameter, 8.0 mm; thickness, 2.0 mm), featuring a bottom layer (diameter, 8.0 mm; thickness, 1.0 mm) of Filtek Z350XT in the A1B, A2B, and A3B shades, and a top layer (diameter, 8.0 mm; thickness, 1.0 mm) filled with Omnichroma. Commission Internationale d’Eclairage <i>L<sup>*</sup>a<sup>*</sup>b<sup>*</sup></i> color measurements and calculations for color differences (Δ<i>E<sup>*</sup><sub>ab</sub></i>) and translucency parameters (TP) of each specimen were performed. Omnichroma exhibited a lighter, more greenish, and blueish color compared to the Filtek Z350XT in A1B, A2B, and A3B shades. With increased thickness, Omnichroma became more yellowish, whereas Filtek Z350XT became less yellowish. Additionally, when Omnichroma was applied over Filtek Z350XT in dual specimens, the yellowness increased further beyond Omnichroma’s original yellowness level. Consequently, Omnichroma achieved clinically acceptable shade matching, especially in the A3 shade, because it aligns well with the original high yellowness of the A3 shade. Additionally, Omnichroma’s superior shade-matching ability was attributed to its higher translucency compared to Filtek Z350XT. Therefore, Omnichroma might be considered useful in pediatric dentistry by simplifying the shade selection process.

A DFT analysis of the antioxidant capacity of scopolin and scopoletin.

Scopolin and scopoletin belong to the class of coumarins and have experimentally proven natural antioxidants. Natural antioxidants are crucial in mitigating the impact of oxidants in the human body through radical scavenging. Even though scopolin and scopoletin are proven antioxidants by experimental results, their antioxidant mechanisms still remained unexplained. In this study, Density functional theory (DFT) calculations were used to study the radical scavenging mechanisms of both scopolin and scopoletin using kinetic and thermodynamics parameters. The global parameters indicated that both scopolin and scopoletin have antioxidant properties. The band gap energy revealed that scopoletin (4.18eV) has strong antioxidant activity compared to scopolin (4.31eV). These studies found that hydrogen atom transfer (HAT) is the primary mechanism for CH3OO• radical scavenging at the C-H bond in scopolin (91.98kcal.mol-1) and the O-H bond in scopoletin (77.05kcal.mol-1) due to their lowest bond dissociation energies. The calculated activation energy ( ) for the radical scavenging reaction, reconfirmed scopoletin ( =11.19kcal.mol-1) performed as a better antioxidant compared to scopolin ( =20.91kcal.mol-1). In this study, the results of DFT calculations confirmed that scopoletin exhibits a higher antioxidant capacity, and HAT mechanism is the most effective radical scavenging mechanism. The antioxidant activity of scopolin and scopoletin was determined by DFT at the B3LYP/6-31G(d) level of theory. Global parameter calculations and frontier molecular orbital analysis were conducted to assess these compounds' capacity for scavenging radicals. Hydrogen atom transfer (HAT), sequential electron transfer proton transfer (SETPT), and sequential proton loss electron transfer (SPLET) mechanisms were the three main mechanisms that were taken into consideration. The potential energy surface (PES) verified the most appropriate processes shown by the enthalpy calculations.

Reactivity of three pyrimidine derivatives, potential analgesics, by the DFT method and study of their docking on cyclooxygenases-1 and 2

Three pyrimidine derivatives, namely 4-[4-(dimethylamino)phenyl]-6-(pyridin-4-yl)pyrimidin-2-amine (DMPN), 4-(4-aminophenyl)-6-[4-(dimethylamino)phenyl]pyrimidin-2-ol (DMPO) and 4-(4-aminophenyl)-6-[4-(dimethylamino)phenyl]pyrimidine-2-thiol (DMPS), with analgesic properties established by a QSAR study, were subjected to reactivity parameter studies using the DFT method, at the B3LYP/6-311++G(d,p) level of theory. Studies of the docking of these molecules to cyclooxygenases 1 (PDB ID: 5U6X) and 2 (PDB ID: 5F19) were also carried out using the CB-Dock online program. Reactivity parameter calculations revealed that the three derivatives are less stable to internal electron transfer, with the lowest energy gap ∆E ranging from 3.63 eV to 3.88 eV, compared with 6.03 eV for ibuprofen (IBP). These derivatives possess the lowest chemical hardnesses η from 1.81eV to 1.94eV versus 3.02eV for IBP and are better electrophiles than IBP with chemical electrophilicity index values ω from 3.20eV to 3.88eV versus 2.64eV for IBP. These derivatives possess greater chemical reactivity than ibuprofen. All three derivatives also feature electrophilic and nucleophilic attack sites. The docking results show that all three derivatives react with cyclooxygenases in the same areas of reactivity as most NSAIDs. These ligands are more active on COX-2 than COX-1, according to complex stability scores which are stronger with COX-2 than with COX-1. In addition, all three derivatives are more active on COX-2 than ibuprofen, with stability score values of -8.6 kcal/mol for DMPN, -9.2 kcal/mol for DMPO, -8.9 kcal/mol for DMPS and -7.6 kcal/mol for IBP. The DMPO ligand forms the most stable complex with COX-2. These three derivatives thus appear to be selective COX-2 inhibitors, with higher stability scores than ibuprofen. All three derivatives also have good absorption, distribution, metabolism and toxicity properties. They can therefore be used as drugs.

Study on potential burnable poison materials for a small modular block-type HTGR design using MgO-BeO as a composite-based moderators

Preliminary analysis of MgO-BeO composite material used as a moderator in a 50 MWt block-type high-temperature gas-cooled reactor (HTGR) was performed in our previous study. The target burnup of 80 GWd/t was achieved with a uniform fuel composition of 17 wt% 235U enrichment and 6 kg of heavy metal per fuel block. However, this resulted in high excess reactivity and a peak in axial power distribution at the core center. Therefore, this study aims to reduce excess reactivity by incorporating burnable poison (BP) material and optimize the axial power profile by introducing a nonuniform fuel composition in the core. Neutronic calculations were performed using the Monte Carlo MVP3.0 code developed by the Japan Atomic Energy Agency (JAEA). In this study, three fuel enrichments of 235U, ranging from 15 wt% to 20 wt%, were distributed across the core while maintaining a constant fuel packing fraction of 45 %. The results showed that the higher power density distribution shifted from the core’s center to its upper part, leading to lower power density in the bottom region than the top. In addition, excess reactivity was reduced by inserting BP rods. Several parametric calculations were performed to achieve minimal excess reactivity without compromising the burnup target. The results showed that the BP rod with a radius of 0.7 cm and 12 wt% of Gd2O3 can reduce the excess reactivity from 25.5 %Δk/k to 13.47 % Δk/k.

Thermodynamic modeling of the processes of purification of primary aluminum from vanadium impurities

This article discusses the interaction of chemical elements in the three-component Al-V-B system. Vanadium reduces electrical conductivity in primary aluminum, which requires its reduction during aluminum electrolysis to values less than 0.02%. In order to reduce the concentration of vanadium impurities, thermodynamic calculations were carried out for the reactions of separation of the metallic phase of aluminum and impurities of vanadium intermetallic compounds through the use of a boron-containing flux. The calculation of thermodynamic parameters was carried out in HSC Chemistry 9.0. for AlB2 and VB2 compounds, the chemical reaction AlB2 + V = VB2 + Al within the operating temperatures of electrolysis and casting of primary aluminum of 650–950°С and the conditions of immersion of boron-containing flux into the melt to a ladle depth of 0.5, 1.0, 1.5 and 2 m, i.e. within the pressure range of 102.39–148.99 kPa. Thermodynamic analysis showed that the Gibbs energy (ΔGT) values in the entire range of operating temperatures of the electrolysis and casting of primary aluminum for VB2 are significantly lower than AlB2, therefore, they will be formed predominantly in this temperature range. The order of stability also suggests that vanadium can be easily removed from aluminum melts by adding boron. The results obtained allow us to conclude that chemical reactions of primary aluminum purification from vanadium impurities can occur due to boron additives.

The Effect of the Structure of the Alcohol Component on the Plasticizing Ability of the Ester of Aliphatic Dicarboxylic Acid

Esters of aliphatic dicarboxylic acids are promising plasticizers of polyvinyl chloride due to their low toxicity and high biodegradability. Plasticized PVC materials containing them are characterized by high frost resistance and heat resistance. In this regard, esters of adipic acid and alkoxylated alcohols with various structures have been obtained. The influence of alcohol structure on the plasticizing ability of ether has been determined. A theoretical assessment of the plasticizing effect of diesters in relation to PVC was performed based on the calculation of Hansen solubility parameters. For this purpose, the thermodynamic compatibility of adipates with PVC was investigated. The processability of esters in the composition of PVC compositions was studied according to the values of the critical temperature of dissolution of PVC. The intervals of transition of plastics from a glassy to a highly elastic state, as well as the depression of the glass transition temperature of compounds containing adipates, were determined. Rheological characteristics of PVC compositions based on the obtained adipates were investigated. It is shown that the chemical structure of the alcohol group determines the important technological and operational characteristics of esters in the composition of polymer materials.

Electrochemical study and modeling of an innovative pyrazole carboxamide derivative as an inhibitor for carbon steel corrosion in acidic environment.

The impact of N,1-dibenzyl-5-methyl-1H-pyrazol-3-carboxamide (BPC) on the carbon steel (CS) corrosion in hydrochloric acid (1M) was studied in this work, considering concentration and temperature effects. Electrochemical investigation indicated that BPC functions as a mixed-type inhibitor. For an optimal BPC concentration of 125ppm, the inhibition efficiency of 91.55% was obtained at 298K. According to adsorption isotherm of Langmuir, the BPC adheres to the CS with standard adsorption free energy (ΔG°ads) of - 26.76kJmol-1. Furthermore, the calculation of dissolution activation parameters revealed an increase in energy (Ea) from 46.48 to 94.97kJmol-1, an elevation in the enthalpy (∆Ha) from 43.89 to 92.37kJmol-1, and a rise in the entropy (∆Sa) from - 91.17 to 51.43Jmol-1K-1 in the presence of 125ppm of BPC. The experimental results were confirmed by quantum chemistry calculations based on density functional theory (DFT) and molecular simulations using the Monte Carlo method. These theoretical approaches also allowed for a comparison of the inhibitory performances of BPC with its protonated form, BPCH, the latter being found more effective. Moreover, the study of the radial distribution function g(r) predicted that the nature of the bond formed with the steel surface is of a chemical type.

Conversion, prediction, and application of strength and stiffness parameters for grouted reconstructed rock mass

Ultrasonic detection has emerged as a rapid method for acquiring rock mass sound velocity and converting it into an elastic modulus parameter, a pivotal technique for investigating the in-situ mechanical properties of rock masses. Despite its significance, accurately deducing rock mass strength from elastic modulus remains a formidable challenge and a pressing issue in the realm of protorock parameter research. This study introduces an innovative artificial intelligence-driven methodology for transforming elastic modulus and strength parameters specific to coal measures through rigorous data analysis and experimental validation. By integrating two illustrative engineering cases, we explore the complexities of water inrush and floor heave issues encountered in tunnels traversing fault zones. The novel strength parameter calculation approach is benchmarked against previous studies, highlighting its superior advantages in terms of effectiveness and applicability. In essence, this research offers a comprehensive framework and practical workflow for translating in-situ acoustic parameter-derived elastic modulus into rock mass strength, serving as a valuable resource for future endeavors in mine water control research.

Integration of In-vivo screening, molecular docking, and molecular dynamics simulations for studying the antiepileptic potential of newly synthesized 5-naphthalen-1-yl-5,10-dihydro-1H-pyrimido[4,5-b]quinoline-2,4-diones in optimized reaction conditions by utilizing l-proline as green catalyst

In a green, one-pot approach, several 5-naphthalen-1-yl-5,10-dihydro-1H-pyrimidoi-[4,5-b]-iquinoline-2,4-dionesi (4a-k) were synthesized via a three-component reaction comprising substituted anilines, naphthaldehyde, and barbituric acids. The reaction conditions were optimized by testing different catalysts (PTSA, CF3COOH, and l-proline) and different solvents. Most of the tested reaction conditions influenced the synthetic reaction. l-proline was more effective with water as a solvent in synthesizing the targeted compounds with high yields. All the synthesized compounds underwent antiepileptic screening using in vivo and in silico methods. In vivo, screening has been performed following the maximal electroshock seizure (MES), and subcutaneous pentylenetetrazole (scPTZ) animal screening methods. The antidepressant screening of the most potent antiepileptic compounds has been tested through a locomotor impairment test (using an actophotometer). The in silico molecular docking and simulation studies were determined by utilizing AutoDock 4.2 version and Groomacs. Among all, compounds 4b, 4d, 4e, and 4j have demonstrated significant antiepileptic activity with effective antidepressant properties. In silico studies (calculation of ADME parameters, molecular docking, and MD simulation) established that targeted molecules have good ADME parameters (good for oral use), the possible mechanism involved interactions primarily with GABAA receptors while interactions with other receptors like VGSCs and NMDA also took place.

Rapid Correction of Turbidity Interference on Chemical Oxygen Demand Measurements by Using Ultraviolet-Visible Spectrometry

We developed a simple, rapid, and high-precision method to compensate for the turbidity interference in the measurement of water parameters using ultraviolet-visible spectrometry. By combining direct orthogonal signal correction (DOSC) with partial least squares (PLS), we corrected the full spectra (220 nm to 600 nm), significantly enhancing the accuracy of the water parameter calculations. First, DOSC was applied to filter out turbidity-related components, retaining only the spectral elements most closely associated with the target substance, without requiring a standard baseline for the turbidity effect. Then, 13 wavelengths were selected from the corrected full spectra to construct the discrete absorption spectra. Further, a PLS regression model was established based on the corrected discrete absorption spectra and their corresponding concentrations. In our experiment, this method effectively eliminated the blue shift and peak height reduction caused by turbidity, especially in shorter wavelengths, which are more sensitive to interference. Moreover, when applied to new samples, the correlation coefficients (R2) between the predicted and actual values improved from 0.5455 to 0.9997, and the root mean square error (RMSE) decreased from 12.3604 to 0.2295 after correction. Overall, the DOSC-PLS method, together with ultraviolet-visible spectrometry, posed a great potential for the precise monitoring of target water parameters in field studies.

Inspecting the structural stability, magneto-opto-electronic, and transport characteristics of half-metallic ferromagnets double perovskite oxide (Sr2MoSbO6): A DFT study

The structural, elastic, mechanical, electronic, thermoelectric, and magnetic properties of the double perovskite Sr2MoSbO6 have investigated in this manuscript using Perdew-Burke-Ernzerhof Generalized Gradient Approximation (PBE-GGA) with an enhanced Trans Blaha modified Becke Johnson potential (TB-mBJ) approach. Through electro-magnetic and elastic exploration, we have determined that this compound is semiconductor, ferromagnetic, and brittle. Strong hybridisation between the Mo and Sr-d orbitals was seen in the Density of states (DOS) results, which, according to their relative quantities, supports the two states' ionic nature. The Mo atoms contribute significantly to the overall magnetic moment, which is 3.0 μB in total. The semiconducting nature of Sr2MoSbO6 is confirmed by the calculation of the overall electronic parameters. Calculations of thermodynamic parameters for temperature ranges of 0–1200 K and pressure ranges of roughly 0–30 GPa show good agreement between theoretical and experimental data. The DFT Boltzmann transport equations have been used to compute thermoelectric properties in relation to temperature and chemical potential. The p-type character of Sr2MoSbO6 is identified by positive values of the Seebeck coefficient. The power factor (PF), Seebeck coefficient (S), figure of merit (ZT), electrical conductivity, and lattice thermal conductivity were also calculated. It was discovered that this perovskite had a merit figure that was almost equal to one, a very high Seebeck coefficient, and strong electrical conductivity—all of which are consistent with its semiconductor nature. These findings suggest a substance with a great deal of promise for thermoelectrical uses. The results are taken into consideration for future experiments and may be future candidates for spintronics applications.

ERGONOMICS AS A FACTOR IN ENSURING SAFETY DURING THE OPERATION OF CONSTRUCTION MACHINES ON THE EXAMPLE OF EXCAVATORS

Problem statement. To improve the safe working conditions of excavator operators, it is important to effectively manage ergonomic quality indicators, increase the reliability of excavators, and improve the sanitary and hygienic conditions and comfort of operators. The set of ergonomic indicators of the operator–excavator system, including controllability, occupancy, serviceability, masterability and manufacturability, defines the concept of ergonomics (a criterion category of quality management that is also considered as an object of management). Changes in construction affect the efficiency of the operator-excavator system, taking into account specific production and technical, natural and climatic, and socio-economic conditions. The re-equipment of construction sites with new generation excavators equipped with modern control, computer information and diagnostic systems, hardware and software for data transmission, processing and analysis not only improves the efficiency of construction work but also changes the safe nature of human-machine interaction. The purpose of the article. Ensuring safety during the operation of construction machines (excavators), taking into account ergonomics criteria, which is an urgent scientific task, the solution of which will improve working conditions and increase the efficiency of excavators. Conclusion. The conducted research has shown that the ergonomic component “man – machine – environment” on the example of improving excavators allows to increase the safety of machines and improve the working conditions of construction machine operators. The use of the mathematical apparatus of fuzzy set theory to evaluate and manage the ergonomics of excavators is due to the nature and specificity of the functioning of the elements of the “operator–excavator” system. Information about the system elements can be represented by subjective opinions or judgements, inaccurate data or errors in measurements and parameter calculations. Therefore, it is necessary to use mathematical tools that take into account quantitative and qualitative information presented in linguistic form.

Solubility behavior of Rosiglitazone in ten pure solvents: Model correlation, thermodynamic calculations, and molecular simulation

Rosiglitazone is an oral antidiabetic medication primarily used to treat type 2 diabetes. Herein, the single crystal structure of Rosiglitazone (a = 14.0613(7) Å, b = 8.4675(4) Å, c = 29.8841(16) Å, space group Pbca, Z = 8, V = 3558.1(3) Å3) was analyzed for the first time. Through solubility measurements, model correlation, thermodynamic calculations, and molecular simulations, the dissolution of Rosiglitazone in ten pure solvents was comprehensively investigated. The solubility order at 298.15 K is acetone > methyl acetate > ethyl acetate > butyl acetate > acetonitrile > alcoholic solvents (methanol, ethanol, n-propanol, iso-propanol, n-butanol). Rosiglitazone exhibits higher solubility in non-alcoholic solvents, whereas its solubility in alcoholic solvents is similar and relatively low. Subsequently, the correlation between the experimentally measured solubility of Rosiglitazone and the Modified Apelblat model, λh model, NRTL model, and Van’t Hoff model was examined. The Van’t Hoff equation calculations proved that the dissolution of Rosiglitazone was an endothermic process driven by entropy and characterized by non-spontaneity. The calculation of solvent polarity and Hansen solubility parameters (HSP) reveals that the primary factor influencing the solubility of Rosiglitazone is polarity in highly polar solvents, while the dominant factor is molecular volume in low-polarity solvents. Furthermore, the molecular interactions of solute and solvents were investigated by molecular simulation, including the calculation of electrostatic potential, 2D fingerprint plots and solvation free energy, which provided insights into the mechanism of Rosiglitazone dissolution behavior in different solvents.

Study on the factors influencing the thermal runaway hazards of styrene-acrylonitrile bulk copolymerization

The styrene-acrylonitrile bulk copolymerization reaction has a high risk of thermal runaway, but the factors influencing the thermal hazards of the reaction have not been adequately investigated. In this paper, the effects of different factors on the thermal runaway behavior of the styrene-acrylonitrile copolymerization are investigated using a combination of simulation and calorimetric testing. The simulation results indicate that increasing the proportion of styrene in the monomer feed significantly delays the onset of thermal runaway. The calorimetric results show that for di-tert-butyl peroxide (DTBP), azodiisobutyronitrile (AIBN) and tert-butyl peroxy benzoate (TBPB) initiators as examples, the TBPB-initiated copolymerization is found to have the maximum temperature-rising rate and pressure-rising rate. Under adiabatic runaway, the temperature and pressure change significantly with increasing TBPB concentration, indicating a great potential risk of thermal runaway. Calculation of kinetic parameters based on calorimetric data reveals thermal runaway mechanism.

Method of calculation of paraxial design parameters of a hybrid catadioptric zoom system with focus tunable elements.

This paper introduces and analyzes a theory for a paraxial design of a hybrid catadioptric optical system with variable focal length, which uses focus tunable optical components. Compared to the conventional zoom lens system, the proposed hybrid optical system can be designed with a smaller length and weight than a lens system of similar characteristics. The hybrid system does not need the movement of individual elements for zooming. All necessary relations for the calculation of the paraxial parameters and the third-order spherical aberration of the hybrid optical system are derived. The presented theory helps to find out the optical power distribution of individual optical elements of the whole hybrid zoom system considering the requirement on the spherical aberration of the system. In addition, the procedure for the calculation of basic design parameters of such an optical system is shown by examples.

Reverse design of load-bearing broadband metamaterial absorber assisted by deep learning

Abstract In response to the current challenges of narrow absorption bandwidth, weak load-bearing capacity, and low design efficiency in absorbing structures, this study focuses on the reverse design of load-bearing broadband metamaterial absorber. A parameterized model of load-bearing metamaterial absorber was developed by integrating the composite sandwich structure with the electromagnetic resonant layers. The resonant layer was constructed using the combination of Vicsek-fractal and circular rings, with resistive films employed to broaden the absorption bandwidth. A deep learning-based forward prediction model was established to accurately predict the absorbance of the metamaterial absorber. The SHapley Additive exPlanations (SHAP) framework was utilized to analyze the forward prediction network, revealing the influence of various design parameters on the absorbance at center frequencies across the L to K band spectrum. Additionally, the Group Teaching Optimization Algorithm (GTOA) was introduced into the design process, leading to the development of an automated reverse design method for metamaterial absorber that can achieve specific design objectives. Using the GTOA-based reverse design method, a metamaterial absorber capable of effectively absorbing vertically incident electromagnetic waves within the 3-20 GHz frequency range was designed. The designed absorbing structure was fabricated, and its absorption performance was measured using the arch method. The measurement results were found to be in good agreement with the simulation data. The absorbing mechanism of the designed metamaterial absorber was analyzed based on the calculation of equivalent electromagnetic parameters and the electromagnetic resonance observed at the resonant frequency. It was determined that the primary absorbing effect is induced by electric resonance triggered by electromagnetic waves. The proposed metamaterial absorber can be applied to radar stealth design for military targets such as naval vessels. The research methodology and approach demonstrate significant generalizability and engineering applicability.