Flux Coefficient Research Articles

Analysis of the Influence of Time Harmonics on the Leakage Coefficient of Canned Permanent Magnet Synchronous Motors

At present, the influence of time-harmonic currents on the leakage flux coefficient of canned permanent magnet synchronous motors (CPMSMs) remains unclear. Therefore, this paper investigates and summarizes the effects of inverter time-harmonic currents on the leakage flux coefficient of the CPMSM. A 1.5 kW, 9000 RPM (Revolutions Per Minute) CPMSM is used as the research subject. Based on a finite element model, the leakage flux coefficients under sinusoidal and non-sinusoidal supply conditions are calculated using the magnetic flux density integration method. Additionally, the study examines changes in the leakage flux coefficient under different harmonic orders and amplitudes. The results indicate that the introduction of fifth and seventh time-harmonic currents by the inverter reduces the leakage flux coefficient, which helps to improve the utilization of the permanent magnets. This research significantly contributes to enriching the theory of inverter-fed permanent magnet motors.

Nanostructured Lipid Carrier-Mediated Transdermal Delivery System of Glibenclamide for Gestational Diabetes: Pharmacokinetic and Pharmacodynamic Evaluation.

Gestational diabetes mellitus (GDM) poses significant risks during pregnancy for both mother and fetus. Adherence to oral antidiabetic medications, like glibenclamide (GB), can be challenging, necessitating novel drug delivery methods. Nanostructured lipid carriers (NLC) offer a promising approach by efficiently permeating the skin due to their small size and lipid-based composition. This study aimed to develop and evaluate transdermal patches loaded with glibenclamide NLCs to treat GDM. Glibenclamide NLCs were prepared using hot homogenization with ultrasonication and melt dispersion method. A central composite design was utilized to optimize the formulations. Transdermal patches containing optimized NLCs were developed using HPMC K 100 and Eudragit L polymers. The patches were evaluated for various parameters, and their pharmacokinetic and pharmacodynamic studies were carried out to assess their safety and efficacy. Optimized NLCs efficiently permeated rat skin. Cell viability studies indicated the nontoxicity of the formulations. NLC-loaded transdermal patches (F2 and F7) showed drug release of 1098 μg/cm2 and 1001.83 μg/cm2 in 24 h, with a 2.5-fold higher flux and permeation coefficient than the GB patch. Pharmacokinetic analysis revealed Tmax of 8 and 10 h and Cmax of 7127 ng/ml and 7960 ng/ml for F2 and F7, respectively, ensuring sustained drug action. AUC0-α was 625681 ng/ml·h and 363625 ng/ml·h for F2 and F7, respectively, indicating improved bioavailability. Transdermal patches incorporating NLCs hold promise for enhancing glibenclamide's therapeutic efficacy in GDM treatment. Improved skin permeation, sustained drug release, and enhanced bioavailability make NLC-based transdermal patches a potential alternative with better patient compliance.

Rizatriptan loaded Bilosomes for Nose to Brain Delivery: Fabrication, Statistical Optimization, and Biological Evaluation

Rizatriptan (RTP) is an anti-migraine drug and after oral administration, it exhibits low bioavailability (45%) due to high first-pass hepatic metabolism. Therefore, to resolve this issue, RTP-loaded bilosomes (BLSs) for brain delivery through the intranasal route were developed. RTP-BLSs were prepared by the thin-film hydration technique and optimized by the L9 Taguchi model. Bile salt (sodium glycocholate, mg), surfactant (Span 40, mg), and edge activator (Cremophor RH 40, mg) were selected as independent factors and their influence was observed on vesicle size (nm) and entrapment efficiency (%). Selected optimized RTP-BLSs (F5) have low vesicle size (204.70 ± 5.8 nm) and polydispersity index (0.260 ± 0.022), good entrapment efficiency (78.32 ± 3.1%), and high zeta potential (-27.6 ± 1.67 mV). The optimized RTP-BLSs exhibited a more sustained released profile (96.41 ± 4.48 % in 24 h) than RTP-Sol (98.65 ± 3.46 % RTP released in 4 h). The flux and apparent permeability coefficient for optimized RTP-BLSs were calculated and found to be 1.069 ± 0.026 μg.cm-2.h1 and 10.690×10-4 ± 0.262×10-4 cm.h-1) and comparatively (P<0.05) better than RTP-Sol (0.548 ± 0.148 μg.cm-2.h-1 and 5.481×10-4 ± 1.476 ×10-4 cm.h-1). The relative bioavailability of RTP formulated within the optimized RTP-BLSs administered intranasally was 2.94 ± 0.78-fold higher than the one obtained with RTP-Sol. The optimized RTP-BLSs showed 1.91 ± 0.15-fold higher absolute bioavailability as compared to intravenous administration RTP-BLSs. The optimized RTP-BLSs showed 64.18 ± 2.34% nose-to-brain drug transport, while RTP-Sol exhibited 20.72 ± 1.46% after intranasal administration. The optimized RTP-BLSs showed a significantly higher brain drug targeting efficiency (279.16 ± 6.37%) as compared to RTP-Sol (126.15 ± 4.79%) given intranasally. From our findings, it can be concluded that the developed BLSs are novel alternative RTP carriers for direct nose-to-brain delivery for the improvement of brain drug targeting.

Experimental study of the flow boiling heat transfer characteristics of teardrop-like micro-pin-finned chip surface in semi-open microchannel

Phase change flow boiling heat transfer in microchannel is a very efficient thermal management mode for high-power electronics/devices. However, it is still a challenge to achieve comprehensive enhancement of flow boiling heat transfer performance at low power consumption. Herein, we devised and manufactured a set of teardrop-like micro-pin-finned chip surfaces, demonstrating their exceptional enhancement in flow boiling heat transfer efficiency within semi-open microchannels with negligible pumping energy input. Benefiting from the effective expansion area, the pinning effect and the streamlined bionic structure of the micro-pin-fins, the staggered teardrop-like micro-pin-finned surface (S37) exhibits simultaneous enhancement of critical heat flux (CHF) and heat transfer coefficients (HTC). The CHF and HTC peaks reached 414.1 W/cm² and 42,153.3 W/m²·K, with maximum enhancement ratios of 52.8 % and 78.1 % relative to the smooth surface. A nearly linear improvement in the heat flux (from 93.1 to 414.1 W/cm², enhanced by 447.8 %) is observed within a minimal fluctuation in wall temperatures, not exceeding 10 °C. The semi-open microchannels provide ample space for boiling nucleation bubbles to move efficiently, enhancing heat transfer performance while maintaining a very low pressure drop (≤1.2 kPa) and without increasing power consumption. In situ observation and analysis of the boiling bubble dynamics indicated teardrop-like micro-pin-finned chip promotes the phase change heat exchange process by massive nucleation sites, and effective control of boiling bubbles by pinning effect. These findings not only provide guidance for the rational design of boiling heat transfer-enhanced surfaces and heat sinks, but also point the way to achieving efficient thermal management of power devices.

Numerical simulation of film boiling heat transfer in immersion quenching process using Eulerian two-fluid approach

This paper presents a Computational Fluid Dynamics (CFD) simulation of the quenching process based on ISO 9950, focusing on the heat flux and heat transfer coefficient integrated over a metal specimen. The numerical method, which employs the two-fluid VOF method and frozen turbulence approach (Cukrov et al., Appl. Sci. 2023, 13, 9144), is used for the transient simulation. Since quenching processes involve complex boiling phenomena shifting from film boiling to nucleate boiling, a standard method based on VOF cannot be applied. The comparison of the simulation results with the ones obtained using correlation, and the data obtained using the Inverse Heat Transfer Analysis (IHTA) method have revealed that the proposed method can accurately predict the heat flux and heat transfer coefficient in the film boiling regime of the immersion quenching process. Note that the previous paper (Cukrov et al., Energies. 2023, 16, 7926.) presented the immersion process modeling and the temperature distribution, while the current paper examines the heat transfer characteristics of the immersion quenching process.

Artemisinin emulgel ameliorates cartilage degradation in knee osteoarthritis: in vitro and in vivo studies.

Aim: Laboratory scale-up of artemisinin-loaded emulgel (ART-emulgel) was carried out and characterized for therapeutic performance in osteoarthritis (OA).Materials & methods: The solubility of ART in various oils, surfactants and co-surfactants were screened for construction of pseudo ternary phase diagram (TPD), followed by scale-up of artemisinin loaded nanoemulsion (ART-NE). ART-NE was amalgamated with Carbopol Ultrez 10-NF to prepare ART-emulgel that was later characterized invitro and invivo to analyze therapeutic efficacy in monosodium-iodoacetate (MIA) induced knee OA.Results: The droplet diameter of ART-NE was estimated to be 104.3±2.593nm with a polydispersity index of 0.245±0.019 in addition to ζ-potential of 0.434±0.028mV. Steady-state flux and permeability coefficient for ART-emulgel were estimated to be 0.651±0.031 µg.cm2/h and 0.245±0.011cm/h, respectively. ART-emulgel demonstrated 43.18% reduction in COX-2 level; 52.28% drop in IL-1β, and 88.78% alleviation of Tumor Necrosis Factor-α (TNF-α) level when compared with monosodium-iodoacetate induced OA rats. ART-emulgel and injectable ART (intra-articular; I.A) portrayed minor synovial erosion compared with blank and diclofenac emulgel. Histopathological evidences indicated restoration of cartilage integrity followed by reduction of OARSI scores in ART-emulgel when compared with disease control animals.Conclusion: ART-emulgel is a potential dosage form for translating into a clinically viable product for the management of OA.

Regimes of stratified turbulence at low Prandtl number

Quantifying transport by strongly stratified turbulence in low Prandtl number ( $Pr$ ) fluids is critically important for the development of better models for the structure and evolution of stellar and planetary interiors. Motivated by recent numerical simulations showing strongly anisotropic flows suggestive of a scale-separated dynamics, we perform a multiscale asymptotic analysis of the governing equations. We find that, in all cases, the resulting slow–fast systems take a quasilinear form. Our analysis also reveals the existence of several distinct dynamical regimes depending on the emergent buoyancy Reynolds and Péclet numbers, $Re_b = \alpha ^2 Re$ and $Pe_b = Pr Re_b$ , respectively, where $\alpha$ is the aspect ratio of the large-scale turbulent flow structures, and $Re$ is the outer-scale Reynolds number. Scaling relationships relating the aspect ratio, the characteristic vertical velocity and the strength of the stratification (measured by the Froude number $Fr$ ) naturally emerge from the analysis. When $Pe_b \ll \alpha$ , the dynamics at all scales is dominated by buoyancy diffusion, and our results recover the scaling laws empirically obtained from direct numerical simulations by Cope et al. (J. Fluid Mech., vol. 903, 2020, A1). For $Pe_b \ge O(1)$ , diffusion is negligible (or at least subdominant) at all scales and our results are consistent with those of Chini et al. (J. Fluid Mech., vol. 933, 2022) for strongly stratified geophysical turbulence at $Pr =O(1)$ . Finally, we have identified a new regime for $\alpha \ll Pe_b \ll 1$ , in which slow, large scales are diffusive while fast, small scales are not. We conclude by presenting a map of parameter space that clearly indicates the transitions between isotropic turbulence, non-diffusive stratified turbulence, diffusive stratified turbulence and viscously dominated flows, and by proposing parameterisations of the buoyancy flux, mixing efficiency and turbulent diffusion coefficient for each regime.

Development and Optimization of Transferosomal Gel for Efficient Topical Delivery of Berberine Hydrochloride

Background: Berberine is an isoquinoline alkaloid with potent anti-inflammatory effects. However, its therapeutic efficacy is often restricted by its poor solubility, absorption, and permeability, especially in topical applications. Transferosomes are elastic vesicular carriers with high skin permeability values and retention, making them suitable for encapsulating hydrophilic and lipophilic actives. Objective: The objective of this research was to develop a transferosome-based topical gel formulation of Berberine hydrochloride (BER) to improve its skin permeability and anti-inflammatory efficacy. Method: The thin film hydration method was used to formulate the BER transferosomes. The effects of independent variables, amount of BER in lipid phase (X1), and lipid (Phospholipon 90G) to surfactant ratio (X2) on BER entrapment and vesicle size were studied using face-centered central composite design. The characterization was performed using differential scanning calorimetry, transmission electron microscopy, and X-ray diffraction. The optimized batch (F5) was incorporated in Carbopol gel and further investigated for viscosity, in vitro and ex-vivo diffusion, skin retention by tape stripping, and in-vivo anti-inflammatory efficiency. Results: The formulation optimized with 50 mg of drug and a 5:1 lipid-to-surfactant ratio (F5) demonstrated higher drug entrapment efficiency (72.11%) and lower vesicle size (77.9 nm). TEM validated the spherical vesicle morphology, whereas DSC and XRD analysis confirmed the molecular entrapment of BER within the phospholipid vesicles. The transferosomal gel demonstrated improved BER diffusion (0.63 mg/cm2) confirmed by in vitro and ex-vivo diffusion experiments that revealed a 6-fold increase in flux and permeability coefficient (0.1053 mg. cm-2.h-1). The drug release from transferosome gel was non-Fickian in nature (n = 0.6575), indicating an integration of diffusion and erosion processes. Furthermore, BER transferosomal gel displayed substantial anti- inflammatory activity in rats (p &lt; 0.001). result: The independent variables exerted a substantial impact on drug entrapment and transferosome vesicle size. The optimized batch (F5) exhibited 72.11 % of BER entrapment and 77.9 nm vesicle size. DSC studies indicated molecular dispersion of BER in phospholipon G. The change in BER crystalline state was indicated by the XRD study. In vitro, diffusion study of Transferosome gel formulation indicated the sustained release by a non-fickian mechanism. Ex vivo skin permeation revealed significant improvement in BER permeation (p&lt; 0.05). Further, the tape-stripping method revealed higher BER skin permeability. In-vivo anti-inflammatory efficacy of BER transferosome gel was significantly higher as compared to plain BER gel. Conclusion: The findings demonstrated the potential of transferosomal gel as a promising approach for efficient drug delivery and therapeutic efficacy.

Momentum flux coefficient effect on vertical two-phase flows: Numerical method comparison

The governing equations of two-phase flows have a safe operating range, and exceeding this range can negatively impact the results. To extend this safe range, one key strategy is to incorporate the momentum flux coefficient into the governing equations. This paper introduces the application of the momentum flux coefficient to no-pressure or free-pressure model equations for the first time, specifically evaluating its performance in downward co-current two-phase flows through numerical methods. A new and improved version of the no-pressure model is also presented. Findings suggest that the force approach method yields more accurate results compared to other methods, whereas the Richmeier method produces unrealistic outcomes at discontinuities. A comparison between the standard and the developed no-pressure models reveals that the latter does not prevent nonphysical mutations and even exacerbates their occurrence. However, the developed no-pressure model successfully reduces numerical distribution production.

A new validated TRNSYS module for phase change material-filled multi-glazed windows

Incorporating phase change materials (PCM) into multi-glazed windows (MW) has been recognized as an effective way to regulate the indoor thermal environment and reduce the energy consumption of buildings. However, the design and calculation of PCM-filled multi-glazed windows (MW + PCM) remain challenging due to the lack of general transient simulation methods and integrated tools. To address this issue, the present study developed a dynamic coupled thermal and optical model for MW + PCM based on the enthalpy-temperature and interface energy balance methods. Then, the model was implemented in C++ and integrated into the TRNSYS software as a new module (Type 2602). In parallel, a test platform comprising two test chambers was established to evaluate the effect of PCM on the thermal and optical properties of the window and to validate the newly proposed module. It was found that compared to the traditional triple-glazed window (TW), the PCM-filled triple-glazed window (TW + PCM) effectively reduces the irradiance through the window by 34.17 % and the maximum temperature of the inner surface by approximately 5.56 °C. While the increase in external surface radiation flux density from 600 to 1200 W/m2 has a diminishing effect on the heat flux variation rate during the heat dissipation process for TW + PCM, it effectively shortens the latent heat absorption time by 0.50 h and increases the temperature difference between the inner and outer surfaces by 3.02 °C. The new module demonstrates satisfactory accuracy through experimental validation and simulation comparisons, with the maximum heat flux coefficient of variance of the root mean square error (CV(RMSE)) less than 6.35 % and 11.25 % under TW and TW + PCM configurations.

Enhanced Phase Change Heat Transfer with Fused Deposition Modeling (FDM) Printed Pit and Pillar (Pi2) Arrays

Phase change heat transfer, crucial in thermal management systems, can be significantly enhanced through optimized surface structures. This study investigates pool boiling heat transfer enhancement using 3D printed structures with carefully designed pillar and pit geometries. We present a novel approach combining the Dual Rise model with separate liquid–vapor pathways to improve Critical Heat Flux (CHF) and Heat Transfer Coefficients (HTC). Using copper-infused Polylactic Acid (PLA) filaments, we created and sintered structured surfaces featuring pit-assisted nucleation sites, interpillar spacing for vapor escape, and pillar roughness for enhanced liquid supply. Experiments with deionized water and ethanol under atmospheric pressure demonstrated substantial improvements over plain surfaces: water showed an 87% increase in CHF and 39% in maximum HTC, while ethanol exhibited even greater enhancements of 122% in CHF and 61% in HTC. These improvements are attributed to the synergistic effects of optimized surface geometry and separated liquid–vapor pathways, reducing counterflow resistance and improving hydrodynamic stability. A theoretical framework based on the Dual Rise model explains these enhancements, providing insights into coupled capillary action and hemiwicking effects in boiling heat transfer. The study introduces predictive models for CHF and HTC enhancement, offering valuable tools for future design optimization in applications ranging from electronics cooling to power plant thermal management and advanced heat exchangers.

Numerical and geometric investigation of pool boiling heat transfer in cavities with isothermal rectangular corrugations

This numerical work presents a geometrical investigation of a corrugated isothermal surface placed in a two-dimensional cavity subjected to unsteady, turbulent pool boiling flows. The main purposes are maximizing the heat transfer rate between the isothermal surface and the surrounding water flow, and the volume of vapor generated into the cavity. The geometric investigation followed the constructal design method, being the ratio Hi/Li (i = 1, 2 or 3) of the corrugations varied for three different numbers of corrugations: N = 1, 2, and 3, keeping constant the corrugations area. The volume of fluid (VOF) and Lee's evaporation-condensation models are used to estimate the volume fractions of water vapor/liquid and interfacial mass transfer. The unsteady Reynolds Averaged Navier Stokes (URANS) continuity, momentum and conservation of energy equations, and volume fraction transport equation, are solved using the finite volume method (FVM) available in software Ansys FLUENT. For closure of turbulence, the k - ɛ model is adopted. For validation of the model, the heat flux and convection heat transfer coefficient obtained for a pool boiling bared surface case are compared with Rohsenow's correlations, and differences lower than 7.0 % are reached. Results indicated a strong influence of the ratio Hi/Li and number of corrugations (N) in the heat transfer rate per unit depth (qs) and dimensionless volume of vapor (Vdim) generated into the cavity. The highest intrusion of the corrugations led to the generation of few large and many small scales, benefiting the thermal performance, regardless of the performance indicator employed. The optimal configuration, N = 3 and H3/L3 = 2.0 improved 49 % and 188 % the Vdim and qs compared with the worst corrugated case, showing the importance of the geometry of the corrugation in this problem.

Percutaneous absorption of two bisphenol a analogues, BPAF and TGSA: Novel In vitro data from human skin

Bisphenol AF (BPAF) and TGSA are analogues of Bisphenol A (BPA). BPAF is used in polymer synthesis, while TGSA is applied in thermal papers. The EU classifies BPAF as toxic to reproduction and TGSA as a skin sensitizer. However, TGSA's other health effects remain unclear. BPAF contamination has been noted among electronic waste workers, and TGSA exposure is documented in various professions. Despite the significance of skin contact, data on skin permeation rates for BPAF and TGSA are limited. This study aimed to generate percutaneous absorption data for BPAF and TGSA following OECD guidelines.[14C]-labeled BPAF or TGSA was applied to human skin samples in vitro using Franz diffusion cells for 20 and 40 h, respectively. Key parameters such as steady-state flux, lag time, and skin permeability coefficient (Kp) were calculated. Furthermore, the distribution of the dose across different compartments, particularly within the skin, was evaluated at the conclusion of the experiment. Sequential strippings and epidermis-dermis separation were conducted for BPAF to predict the potential absorption of the remaining dose present within the skin.The permeability coefficients for BPAF and TGSA were found to be 1.9 E−03 and 1.6 E−03 cm/h, with 22% and 23% of the applied doses absorbed, respectively. Both chemicals are classified as "fast" penetrants based on their Kp values. These findings suggest that BPAF and TGSA are absorbed through the skin, highlighting potential occupational risks through dermal exposure. The new percutaneous absorption data will enhance the assessment of the occupational risks.

Innovative and environmentally friendly MICP surface curing: Enhancing mechanical and durability properties of concrete

Concrete curing is a critical factor influencing its mechanical properties and durability. Traditional curing methods, such as water curing and plastic film curing, have significant limitations, including high water consumption and environmental pollution. This study introduces Microbial Induced Carbonate Precipitation (MICP) as an innovative, environmentally friendly curing method for ready-mixed concrete, addressing the urgent need for sustainable construction practices. The feasibility of MICP surface curing is investigated through comprehensive mechanical and durability tests, coupled with microscopic analyses to understand the underlying mechanisms. The results demonstrate that MICP curing substantially enhances concrete performance. Compared to traditional water curing, the samples cured using MICP have increased compressive strength and splitting tensile strength by up to 31.69% and 24.66%, respectively. Additionally, MICP surface curing significantly reduced capillary water absorption, electric flux, and chloride ion migration coefficient by 12.83%, 15.50%, and 17.36%, respectively. It is found that the optimal concentration of Ca2+ in the MICP solution initially improves concrete performance, which then diminishes at higher concentrations due to bacterial activity inhibition. Spraying the MICP solution at appropriate intervals and increasing the number of treatments further improved concrete properties by ensuring a more extensive and dense deposition of CaCO3. Microscopic analyses, including XRD, TG, and SEM-EDS, revealed that MICP surface curing leads to the formation of vaterite and calcite, which densely cover and fill microscopic cracks and pores, ensuring adequate hydration and simultaneously enhancing the concrete's mechanical and durability properties. This study concludes that MICP surface curing provides superior performance than traditional methods and offers a more sustainable and environmentally friendly curing method.

Surface structures and wettability: Their roles in enhancing nucleate boiling heat transfer of refrigerants

Nucleate boiling is an effective heat transfer mechanism. Previous studies have demonstrated that modifying surface structure or wettability can independently improve nucleate boiling efficiency; however, the combined effects and optimal modification sequence remain underexplored. This research aims to comprehensively analyze the influence of surface structure and wettability on the nucleate boiling heat transfer performance of refrigerants. Different surface structures and wettability were prepared using surface polishing, laser ablation, mechanical cutting, and a combination that involved initially employing laser ablation, followed by the application of chemical etching, and finishing with the treatment using materials possessing low surface energy. The static contact angles on these surfaces were measured via the capillary rise method, followed by pool boiling experiments and bubble behavior visualization. The results show that increasing surface wettability can enhance bubble departure frequency and capillary wicking, thereby improving critical heat flux and heat transfer coefficient. The key to optimizing surface modification to enhance critical heat flux involves constructing alternating high and low nucleation core regions to reduce interactions between bubbles; for enhancing heat transfer coefficient, the key lies in constructing compact nanoscale structures that expand the heat transfer and nucleation area, followed by improving wettability.

Scrutiny of pseudoplastic nanofluid flow under the influence of magnetic hydrodynamics with chemical reaction across the cylinder with slip boundary condition

Buoyantly induced flows possess diversified utilizations in numerous engineering processes for instance, reactor cooling through passive strategy, LED lights, pipes manufacturing, ship funnel and many more. Galvanized sheets sticked to form a hollow cylinder is used for fast cooling in naval ship and chimney of steam power plant. In view of such mesmerizing significance of flow and thermal attributes of fluid over vertical cylinder, current effort is articulated. For this purpose, Williamson fluid model is accounted and nanoparticles are also induced to envision advanced thermal features in the flow over vertically oriented cylinder. Physical effectiveness of magnetic field implications and chemical reactive species are entertained to notice change in hydrothermal and mass fields. Slip boundary constraint along with stagnant flow at the surface of cylinder is considered to inspect behavior in free stream region. The fundamental governing equations of problem are attained in the sense of PDEs by utilizing the concept of boundary layer approximation and converted into coupled nonlinear ODEs by substituting specific similar variables. Numerically the resulting ODEs are resolved by making the use of bvp4c built in MATLAB routine, the outcomes are attained and arranged in graphical and tabular manner. The influence of pertinent flow parameters such as (0.1 ≤ We ≤ 1.0), (1.0 ≤ M ≤ 3.0), (1.0 ≤ Pr ≤ 11), thermophoresis parameter (0.5 ≤ Tp ≤ 4.5), (1.0 ≤ Bp ≤ 5.0), (0.05 ≤ Nr ≤ 0.7), and (0.5 ≤ Kc ≤ 5.0) are examined on the momentum, thermal and concentration distributions. It is manifested that the velocity distribution depreciates by uplifting magnetic field strength. Increment in magnitude of wall drag and convective heat transfer is perceived by enhancing Prandtl number. It is inferred that friction coefficient in absolute sense and heat flux coefficient tends to exceed against elevation in (We). From comprehensive analysis, declination in velocity and thermal field is depicted versus Reynold number whereas, contrary aspects are visualized in concentration. Enhancement in the value of surface drag and thermal flux is revealed versus (Re).

A hydrophilic–lipophilic deviation model in formulating microemulsion for topical application

The hydrophilic–lipophilic deviation (HLD) model is firmly established in oil recovery and can be potentially applied in various other fields. In this work, the HLD concept is systematically used to prepare microemulsion for topical application using isopropyl myristate (IPM), squalane, water, mixed nonionic surfactants and magnesium ascorbyl phosphate (MAP). The clear water-in-oil (W/O) microemulsion formed spontaneously and has a consistent submicron droplet size below 30 nm. The microemulsion was characterized by particle size, electrical conductivity, electrophoretic mobility, viscosity and in vitro diffusion. The addition of one part of squalane to three parts of IPM in the oil blend prevented the percolation phenomenon and reduced the electrophoretic mobility of MAP. The inclusion of squalane to IPM in the oil phase reduced the cumulative amount of MAP permeated from the microemulsion, reduced the permeation coefficient of MAP and increased the lag time, reduced the steady-state flux and permeability coefficient as well. The microemulsion provided an alternative approach to encapsulate the water-soluble MAP in an oil matrix as a cosmetic active ingredient for the manufacture of personal care products.

Localization of a Crack in Moving Cylindrical Ferromagnetic Rods by Measuring the Fourier Coefficients of the Leakage Magnetic Flux

Localization of a Crack in Moving Cylindrical Ferromagnetic Rods by Measuring the Fourier Coefficients of the Leakage Magnetic Flux

Study of interfacial competitive distribution and synergistic permeation in nanofiltration separation of Salvia divinorum acids from the aqueous extract

The contact between solution and membrane during nanofiltration separation produces the interfacial layer fluid, and the competitive distribution laws of solutes in the interfacial layer are difficult to be analyzed, giving rise to diversified separation results that are challenging to explain using traditional nanofiltration separation theory. Four Salvia divinorum phenolic acid components—sodium salvinorin, protocatechuic aldehyde, rosmarinic acid, and salvianolic acid B—which have gradient relative molecular masses and dissociation constants, were selected as the objects of study. The nanofiltration separation parameters, such as membrane flux and permeation rate of the Salvia divinorum phenolic acids and their variability with the monomer solution under the complex solution environment were systematically analyzed. Based on the correlation between the concentration of the interfacial layer and the initial concentration, membrane flux and mass transfer coefficient in the theory of concentration polarization, the concentration of the interfacial layer of the nanofiltration membrane was calculated. This was combined with the state of association characterized by the distribution of particle sizes in the solution, the research model based on the ‘Associative State-Interfacial Competition-Separation Behavior’ was constructed, and the competitive and synergistic membrane separation regulations of the constituents of salvia phenolic acids were clarified. In acidic solutions, van der Waals forces dominate the interfacial competition, and of the four phenolic acids, salvinorin acid B diffused most easily to the membrane surface, showing that the component with the larger relative molecular mass inhibited the penetration of the smaller component; In alkaline solution, Coulomb force and Van der Waals force together dominate the interfacial competition, and the more acidic sodium salvinorin, etc., would preferentially react with hydroxide. At the same time, combined with the feature that the more molecular states in the particle size distribution of the solution are more likely to form aggregates, it was proven that the dissociation of protocatechuic acid aldehyde was inhibited, and its molecular state was more complete. It was shown that the more acidic sodium salvinorin and others facilitated the less acidic protocatechuic aldehyde to pass through the membrane.

Finite element simulations to explore thermofluidic transport mechanism in permeable medium by using Darcy Brinkman-Forchheimer model

Diversified utilizations of permeable domains are found in cooling systems, gas recovery, and insulation engineering. Therefore, this research focused on investigating the heat transport aspects imparted by the buoyantly driven flow of a viscous fluid saturated in a permeable L-shaped enclosure. Darcy Brinkman-Forchheimer model is considered in the present pagination to envision permeability aspects. In addition, entropy generation is considered to encapsulate the disordered form of the system. In this study, an l-shaped domain with heated steps and insulated horizontal boundaries was entertained, while the vertical walls are kept cold. Non-persistent buoyancy forces are employed to elucidate the impact of the gravitational forces. The mathematical formulation of the problem is examined in the form of a dimensionless coupled partial differential system after normalizing the variables. Subsequently, the Galerkin finite element method was implemented using a commercial multigrid software (COMSOL) to find a solution to the constructed problem. The influence of the included parameters on the related distributions and quantities of interest in a comparative sense is evaluated using sketches and tables. A comparison of the results along with a grid-independent test is also performed to ensure the reliability of the computational procedure and computed outcomes. It is inferred that the total entropy and averaged Nusselt number increase as the Darcy number increases by 21.39% and 10.76%, respectively, whereas the Bejan number exhibits the opposite trend. Raising the aperture ratio of the enclosure results in a reduction of the heat flux coefficient, and the ECOP also indicates a reduction in entropy.