Mass Transfer Properties Research Articles

Investigation of Thermal Management Capacity of Casson Electrolytes in Porous Electrodes in Lithium‐Ion Battery Applications

ABSTRACTThe study of the Casson electrolyte in lithium‐ion batteries (LIBs) is important because of their complexities due to tougher operational conditions and other challenges during charging–discharging challenges with their improved thermal management capacity and enhanced safety. This further optimizes the thermal management avoiding chances of hot spots or thermal runaway, thereby making LIBs safer. In this investigation, convective loads for non‐Newtonian fluid as electrolyte Casson‐type boundary layer flow related to plate and flat surfaces in non‐Darcy permeable porous electrodes have been deliberated. We have employed the Optimal Homopotic Asymptotic Method technique to solve the equation of the system. The effects and influences of Casson factors, permeability, flow constraints, Prandtl values related to flow and thermal dissipation, and boundary layer profiles have been studied. From the results, it is concluded that thermal parameters and porousness have affected the system, and the upsurge in the porousness actually decreases heat transport effects and proportions. The results of this study are relevant to the development of more effective porous electrodes for achieving high performance with long cycle life. These studies help improve the utilization of mass and heat transfer properties, as affected by the non‐Newtonian behavior of the electrolyte, to help in the design of next‐generation LIBs with higher energy density along with fast charge/discharge rates.

Mesoporous Boron-Doped Carbon with Curved B4C Active Sites for Highly Efficient H2O2 Electrosynthesis in Neutral Media and Air-Supplied Environments.

Hydrogen peroxide (H2O2) electrosynthesis via the 2e- oxygen reduction reaction (ORR) is considered as a cost-effective and safe alternative to the energy-intensive anthraquinone process. However, in more practical environments, namely, the use of neutral media and air-fed cathode environments, slow ORR kinetics and insufficient oxygen supply pose significant challenges to efficient H2O2 production at high current densities. In this work, mesoporous B-doped carbons with novel curved B4C active sites, synthesized via a carbon dioxide (CO2) reduction using a pore-former agent, to simultaneously achieve excellent 2e- ORR activity and improved mass transfer properties are introduced. Through a combination of experimental analysis and theoretical calculations, it is confirmed that the curved B4C configuration, formed by mesopores in the carbon, demonstrates superior selectivity and activity for 2e- ORR due to its weaker interaction with *OOH intermediates compared to planar B4C in neutral media. Moreover, the mesopores facilitate oxygen supply and suppress the hydrogen evolution reaction, achieving a Faradaic efficiency of 86.2% at 150mA cm-2 under air-supplied conditions, along with an impressive O2 utilization efficiency of 93.6%. This approach will provide a route to catalyst design for efficient H2O2 electrosynthesis in a practical environment.

Miscible Polymer Blend Membranes Bearing Pyrrolidone for Fractioning Sulfuric Acid and Sulfates

ABSTRACTIon exchange membranes of new chemistry based on polymer blends are proposed through a convenient solution‐blending process using the hydrophobic commodity polymer polyvinyl chloride (PVC) and the hydrophilic polyvinylpyrrolidone (PVP), which are completely miscible. The pyrrolidone groups can be protonated to form oxonium ions, functioning as transient fixed positive charges for fractioning sulfuric acid and sulfates via diffusion. The influence of PVC molecular weight and the membrane composition on the physical, chemical properties, and mass transfer performance of PVC‐PVP blend membranes was systematically investigated. After equilibrium in 2.68 mol/L sulfuric acid, the sulfuric acid, and water contents in the blend membranes increase with the increase of the membrane PVP contents (20–75 wt%). The permeability coefficients of sulfuric acid and ferrous sulfate for the blend membranes also exhibit a gradual increase. Membranes of mass transfer properties comparable to commercial ones can be easily obtained by tuning the membrane PVP contents. It is proved that the larger sulfuric acid permeability over sulfates (FeSO4 as an example) is due to both larger solubility and diffusion coefficient of sulfuric acid in the membrane phase. The optimal PVC‐PVP blend membranes have shown nice performance in fractioning sulfuric acid from sulfates, when treating titania waste acid. This study provides valuable guidance for the design of high‐performance yet low‐cost ion exchange membranes with pyrrolidone chemistry from commodity polymers for resource recovery.

Biomedical uses of Casson blood nanofluid with gold nanotubes: Mathematical modeling of blood flow in porous arteries

Gold nanoparticles (1–100[Formula: see text]nm) are minute particles and are safer to disperse into blood to deal with many internal ailments. Magnetized gold nanoparticles with their promising effect in biomedicines are the epicenter of research for many scientists. This study is an attempt to apply nanomaterials in the field of bio-medicine. Particularly, the study surrounds around heat and mass transfer property of blood nanofluid in porous artery of narrow diameter. This work involves modeling a layer of gold nanoparticles in blood flow along porous surface as well as effect of reaction. Flow of blood is assumed to be non-Newtonian (in vessels of small diameter). Magnetic effect is also clubbed with the study. Standard procedure of reducing equations is used. Nanoparticles’ layering concentration in the range of 2–9% delivers noticeable effects on conduction of heat and performance of blood flow. Numerical solution was obtained by MATLAB after shooting an appropriate guess. Accounting effect of layering of nanoparticle on Casson parameter leaves a noticeable impact on results. Graphical plots are used to extract impact of each parameter on heat conduction and velocity of the blood. The findings threw light on importance of magnetic parameters in relocating heat. The increase in thickness of layer of nanoparticle from 2[Formula: see text]nm to 6[Formula: see text]nm, increased heat conductivity and performance significantly. The information from this work can be basis of novel method of treatment in medical field and can deliver the base for future experimentation.

The Synthesis, Characteristics, and Application of Hierarchical Porous Materials in Carbon Dioxide Reduction Reactions

The reduction of carbon dioxide to valuable chemical products could favor the establishment of a sustainable carbon cycle, which has attracted much attention in recent years. Developing efficient catalysts plays a vital role in the carbon dioxide reduction reaction (CO2RR) process, but with great challenges in achieving a uniform distribution of catalytic active sites and rapid mass transfer properties. Hierarchical porous materials with a porous hierarchy show great promise for application in CO2RRs owing to the high specific surface area and superior porous connection. Plenty of breakthroughs in recent CO2RR studies have been recently achieved regarding hierarchical porous materials, indicating that a summary of hierarchical porous materials for carbon dioxide reduction reactions is highly desired and significant. In this paper, we summarize the recent breakthroughs of hierarchical porous materials in CO2RRs, including classical synthesis methods, advanced characterization technologies, and novel CO2RR strategies. Moreover, by highlighting several significant works, the advantages of hierarchical porous materials for CO2RRs are analyzed and revealed. Additionally, a perspective on hierarchical porous materials for CO2RRs (e.g., challenges, potential catalysts, promising strategies, etc.) for future study is also presented. It can be anticipated that this comprehensive review will provide valuable insights for further developing efficient alternative hierarchical porous catalysts for CO2 reduction reactions.

MnO2 Nanowire Thin Mesh With Enhanced Mass Transfer as Hydroxide Exchange Membrane Fuel Cell Cathode

AbstractHydroxide exchange membrane fuel cells (HEMFCs) are promising due to the potential use of nonprecious metal catalysts. However, the performance of HEMFCs based on nonprecious catalysts is still unsatisfactory, and one reason for this is hindered mass transfer in the catalyst layer. In this study, we employ a hydrothermal method to grow in situ a MnO2 nanowire thin mesh (NTM) catalytic layer on the gas diffusion electrode. The HEMFC prepared with MnO2 NTM cathode achieves a peak power density of 425 mW cm−2, surpassing the performance of the HEMFC prepared using the traditional powder catalyst spraying method by four times. High‐frequency resistance and limiting current tests indicate that the MnO2 NTM reduces ohmic resistance and improves mass transfer, thereby enhancing the HEMFC performance. Furthermore, the peak power density of the HEMFC is increased to 626 mW cm−2 by depositing additional active Co3O4 nanoparticles on the MnO2 NTM. These findings demonstrate that an interconnected and porous catalyst layer structure is beneficial for improving mass transfer properties, which in turn enhances HEMFC performance.

Enhanced tetracycline degradation using carbonized PEI-grafted lignin microspheres supported Fe-loading catalyst across a wide pH range in Fenton-like reactions.

Traditional homogeneous Fenton systems face limitations, including a narrow pH range, potential secondary pollution, and poor repeatability. In this study, these bottlenecks in tetracycline wastewater treatment were addressed with using carbonized porous polyethyleneimine-grafted lignin microspheres (PLMs) supported Fe-loading catalysts (PLMs/Fe-C). An optimized PLMs/Fe-C catalyst under specific conditions (carbonization temperature: 350 °C, PLMs: Fe = 1:1, and alkali lignin: PEI = 1:4) was developed, which proved to be an efficient Fenton-like catalyst for tetracycline (TC) degradation. TC degradation results showed that the PLMs/Fe-C + H2O2 system achieved a high removal efficiency of 100 % within 150 min (50 mL TC with an initial concentration of 50 mg/L, 0.015 g catalyst, 0.5 mL H2O2), demonstrating its applicability over a wide pH range (3-10) and the capability to remove multiple pollutants (2,4-D, BPA, Lev, etc.). This efficiency was attributed to the stronger electron-donating ability and mass transfer properties derived from the porous structure and functional groups. Arrhenius fitting analysis revealed a lower activation energy (E = 52.98 kJ/mol) for the PLMs/Fe-C, indicating a more accessible reaction. Additionally, the removal efficiency marginally decreased from 100 % to 98.32 % after five cycles, demonstrating excellent reusability. Mechanistic investigations indicated that the PLMs/Fe-C can activate H2O2 to produce reactive oxygen species •OH, 1O2, effectively degrading TC.

Tailoring high-performance bipolar membrane for durable pure water electrolysis

Bipolar membrane electrolyzers present an attractive scenario for concurrently optimizing the pH environment required for paired electrode reactions. However, the practicalization of bipolar membranes for water electrolysis has been hindered by their sluggish water dissociation kinetics, poor mass transport, and insufficient interface durability. This study starts with numerical simulations and discloses the limiting factors of monopolar membrane layer engineering. On this foundation, we tailor flexible bipolar membranes (10 ∼ 40 µm) comprising anion and cation exchange layers with an identical poly(terphenyl alkylene) polymeric skeleton. Rapid mass transfer properties and high compatibility of the monopolar membrane layers endow the bipolar membrane with appreciable water dissociation efficiency and long-term stability. Incorporating the bipolar membrane into a flow-cell electrolyzer enables an ampere-level pure water electrolysis with a total voltage of 2.68 V at 1000 mA cm–2, increasing the energy efficiency to twice that of the state-of-the-art commercial BPM. Furthermore, the bipolar membrane realizes a durability of 1000 h at high current densities of 300 ∼ 500 mA cm–2 with negligible performance decay.

Fabrication of MXene-TiO2 nanotube composite and their electrochemical study in acidic and alkaline medium

MXenes, a novel class of two-dimensional (2D) transition metal carbides, nitrides, and carbonitrides, have emerged as promising electrocatalysts for the hydrogen evolution reaction (HER) due to their remarkable electrical conductivity, exceptional structural and chemical stability, and large active surface area. In this study, we synthesized a 1D/2D Ti3C2 MXene-TiO2 nanotube (TNT) composite via electrostatic self-assembly method. Field emission scanning electron microscopy (FE-SEM) confirmed the distinctive accordion-like, multilayered morphology of Ti3C2Tx MXene, while X-ray diffraction (XRD) provided the crystalline phase of the composite. High-resolution transmission electron microscopy (HR-TEM) revealed an average particle size of 38.41 nm for the MXene-TNT nanocomposite. Additionally, X-ray photoelectron spectroscopy (XPS) confirmed the composite composition, highlighting the synergistic integration of MXene and TiO2 nanotube that enhances electrical interactions and contributes to superior catalytic performance. Electrochemical performance was assessed using cyclic voltammetry (CV), linear sweep voltammetry (LSV), and electrochemical impedance spectroscopy (EIS) in both acidic and alkaline media. Among the composites, the MXene-TNT (1:10) loading demonstrated a low Tafel slope of 65 mV/dec in acidic media, indicative of enhanced mass transfer properties. In alkaline media, the MXene-TNT (1:5) composite exhibited a Tafel slope of 160 mV/dec for HER, with kinetic performance proving more favorable in the acidic environment. Additionally, the composite displayed a Tafel slope of 149 mV/dec for the oxygen evolution reaction (OER) in acidic media. This study demonstrates a feasible approach for developing high-performance, cost-effective electrocatalytic materials for efficient hydrogen production, utilizing MXene as a co-catalyst.

Process intensification for low-saline water electrochemical treatment

This work tries to enhance the mass transfer and electrical properties of the electrochemical treatment in low-saline water using process intensification. Particle electrodes, turbulence promoters, electrode assembly, and bubble-induced convection are applied to the process intensification electrochemical process. The experimental and modeling results suggest that bubble-induced convection and electrode assembly structure can induce significant turbulent disturbance around the electrode surfaces. Moderate forced convection and electrode assembly structure can significantly enhance mass transfer, including convective migration and electric migration. It results in uniform concentration distribution and better electrochemical properties. The process intensification electrochemical process exhibits excellent reactor performances and pollutant removal abilities, e.g. COD and NH3-N. The dredging tail water and natural lake waters can be purified to the IV level of the environmental quality standards (GB 3838–2002) with a moderate cost. It can on-site and ready-to-use purify water using air and renewable electricity.

Fibrillated Films for Suspension Catalyst Immobilization-A Kinetic Study of the Nitrobenzene Hydrogenation.

The immobilization of suspension catalysts in flexible, fibrillated films offers a promising solution to the mass transfer limitations often encountered in three-phase hydrogenation reactions. This study investigates the catalytic performance and mass transfer properties of fibrillated films in the hydrogenation of nitrobenzene to aniline, comparing them to free-flowing powdered catalysts. Fibrillated films were prepared from Pd/C catalysts with varying thicknesses (100-400 µm), and their performance was evaluated through kinetic studies in both batch reactors and microreactors. The specific activity of the films was significantly influenced by film thickness with thinner films demonstrating lower mass transfer limitations. However, mass transfer limitations were observed in thicker films, prompting the development of alternative film designs, including enhanced macro-porous films and sandwich structures. These modifications successfully minimized diffusion limitations, achieving similar specific activity to the powder catalysts while maintaining the mechanical stability of the films. This work demonstrates the feasibility of using fibrillated films for continuous catalytic processes and highlights their potential for efficient catalyst reuse, avoiding filtration steps and enhancing process sustainability. Furthermore, while PTFE remains indispensable for producing such films due to its mechanical and thermal stability, ongoing research focuses on identifying more environmentally friendly alternatives without compromising performance.

In-situ growth of nickel-based catalysts on the surface of macroporous Al2O3 for CO2 methanation

Macroporous catalysts often exhibit excellent mass and heat transfer properties, which can reduce pressure drop and mitigate hot spot formation during the reaction process. Addressing the issues of the active component sintering due to the strong exothermicity of CO2 methanation and the demand for operation at high space velocities, in this work, a nickel-based catalyst with high surface area and large pore size and pore volume was prepared by in-situ growth of NiMgAl layered double hydroxide (NiMgAl-LDH) precursors on the surface of macroporous Al2O3. The effects of calcination temperature, reduction temperature, and space velocity on the catalyst structure and reaction performance were investigated. The results demonstrate that the catalyst phase composition can be controlled by adjusting the calcination temperature, while the reduction degree of Ni is regulated by altering the reduction temperature, which are effective in inhibiting the sintering of Ni, increasing the number of active Ni0 sites, and then enhancing the catalytic activity of Ni-MgO/Al2O3. By conducting the calcination of NiMgAl-LDH precursor at 400 °C and subsequent reduction at 650 °C, the resulted Ni-MgO/Al2O3 catalyst shows the highest active Ni surface area and exhibits the highest CO2 conversion and CH4 selectivity in the CO2 methanation, suggesting that the surface area of metal nickel is a crucial factor for the catalytic performance of Ni-MgO/Al2O3. Furthermore, the Ni-MgO/Al2O3 catalyst performs well at a high space velocity of WHSV = 80000 mL/(g·h) and a good stability at 550 °C, where the CO2 conversion and CH4 selectivity keep at 54% and 79%, respectively.

Development and performance evaluation of a novel solar mid-and-low temperature receiver/reactor with packed metal foam

Solar-driven hydrogen production from methanol decomposition (MD) is an important method of storing solar energy as clean fuels and improving the solar energy utilization efficiency. Catalyst preparation is one of the key steps, but conventional Cu-ZnO-Al2O3 particle catalysts lead to uneven reactor temperature, reducing the efficient conversion of solar energy into fuels. To alleviate this challenge, a monolithic catalyst utilizing packed foamy copper as a carrier is developed with exceptional thermal and mass transfer properties. The experimental results validate its excellent performance in hydrogen production using MD. The absolute conversion increases by an average of 12.11 % at 250 °C and further by 14.43 % at 270 °C compared to the particle catalyst. Based on these findings, a novel solar reactor is proposed, and a multi-field coupling model is built. The comparative results verify the performance advantage of the developed solar thermochemical receiver/reactor with packed metal foam-based catalyst. It maintains high conversion rates and solar-to-fuel energy efficiency, while alleviating overheating problems caused by traditional particle catalysts. Under the design conditions, the new reactor significantly improves the absolute conversion of methanol and the energy efficiency of solar-to-fuel conversion by 4.57 % and 3.00 %, respectively, resulting in 92.64 % and 67.56 %. This study provides a theoretical basis and technical solution for more stable and efficient use of mid-and-low temperature solar energy.

Study on Mass Transfer and Physicochemical Properties of Avocado During Osmotic Dehydration

A previous study found that mass transfer occurring during the osmotic dehydration (OD) process. This phenomena is possible causing modification in physicochemical properties; therefore, understanding the OD effect on quality attributes is important. This research aimed to study the impact of sucrose concentration and immersion time on the kinetics of mass transfer and the physicochemical properties of avocado (Persea americana var. Miki) during the OD process. The samples were immersed in a sucrose solution (45, 55 and 65 ° Brix) for up to 300 min, then the mass transfer parameter and physicochemical properties were evaluated. The results showed that the highest rate of water removal (WR) was –0.037 g.g–1.h–1 using the 55 ° Brix solution, which also led to an increase in the soluble solid gain (SSG) value to 0.0126 g.g–1.h–1, while the highest WR/SSG ratio was obtained after 180 min of immersion using 65 ° Brix (2.451). A 2nd-order polynomial model accurately describes avocado mass transfer kinetics and their relationship to physicochemical properties. The model showed the best adjustment for WR, SSG, and weight loss (WL), as pointed out by R2 = 0.9671, 0.8968 and 0.9573, respectively. WR has a negative effect on firmness (R2 = 0.9278), vitamin C (R2 = 0.9349), and total fat (R2 = 0.8954). The uptake of sucrose correlated with decrease of vitamin C (R2 = 0.9391), whereas WL also affected the loss of total fat (R2 = 0.8288). The OD process modified the chroma of the avocado by reducing lightness, increasing greenness and yellowness, and yet protecting the flesh from the browning effect. Overall, this study provides insights into the relationship between mass transfer and physicochemical properties, and it is useful to predict the final condition of the osmo-avocado before subsequent processes. HIGHLIGHTS Immersing the avocado in a 55 ° Brix solution resulted in the highest rate of water removal (WR) and soluble solid gain (SSG). The highest ratio of WR and soluble solid gain (WR/SSG) was obtained at 180 min of immersion using a 65 ° Brix solution. The 2nd-order polynomial model fits the mass transfer parameters (WR, SSG, and weight loss/WL). WR contributed to a softened texture, color contrast, degradation of vitamin C, and total fat content. The combination of mass transfer and physicochemical property models is useful for designing the OD process and predicting the final condition of osmo-avocado. GRAPHICAL ABSTRACT

Synergistic effect of reinforced cellulose nanofibrils/polyethylene glycol embedded particles in ammonia nitrogen wastewater: An in-depth microbial denitrification analysis

The encapsulation and immobilization technology provide a good growth environment for bacteria, strong protection ability, improved survival rate, and resistance to adverse environmental factors. Cellulose nanofibrils (CNF) with polyhydroxyl structure improve the elasticity, tensile properties, mechanical strength and gel strength of embedded particles through non-covalent forces. Polyethylene glycol (PEG) is a water-soluble polymer with unique carbon‑oxygen chain as the core skeleton. The ether bonds present in each unit give PEG extremely strong hydrophilicity and solubility. CNF and PEG to reinforce SA (sodium alginate) and PVA (polyvinyl alcohol)-SA embedded particle were adopted to treat ammonia nitrogen wastewater. The ammonia diffusion coefficients and oxygen diffusion coefficients of the CNF/PEG/SA and CNF/PEG/PVA-SA were 0.454 × 10−9, 0.286 × 10−9, 0.672 × 10−9 and 0.493 × 10−9 m2/s, respectively. The physicochemical properties of embedded particles were characterized by mass transfer characterization, SEM, XRD, FTIR, and BET analysis. The specific surface areas of CNF/PEG/SA and CNF/PEG/PVA-SA increased to 2.583 m2/g and 3.962 m2/g, respectively. The removal efficiency of NH4+-N, COD and TN in the CNF/PEG/PVA-SA system was 90 %, 74 % and 80 % at 30 °C. By HRT 8 h, the removal efficiency of NH4+-N, chemical oxygen demand (COD)and total nitrogen (TN) by the reinforced system was 94.35 %, 63.07 % and 73.84 %, respectively. The neutral to weakly alkaline pH range showed the highest removal efficiencies of NH4+-N, COD, and TN, at 88.51 %, 74.95 %, and 77.56 %, respectively. The half-saturation constant K was 82.98 mg/L, and the maximum ammonia oxidation rate (Vmax) was 358.92 mgN/(L-particles-h). The reinforced system showed zero-order reaction kinetics. Nonlinear fitting of each initial NH4+-N concentration and ammonia oxidation rate was carried out using the Michaelis-Menten equation. In reinforced embedded particles, microbial genomic data (KEGG; MetaCyc database annotation) analysis was conducted. The reinforced system demonstrated enhanced strength, specific surface area, mass transfer properties, resistance to adverse external environmental factors, and microbial survival rate for the effective treatment of NH4+-N wastewater.

Investigation of heat and mass transfer properties of the wave staggered round table cooling flow field with a three-stage forked distribution zone

Research on proton exchange membrane fuel cells (PEMFC) has mainly focused on the design of gas channels, often neglecting the effects of distribution zones and cooling flow fields (CFF) on the cell. Therefore, a novel bipolar plate (BP) structure of metallic material is proposed in this paper, which adopts a three-stage forked distribution zone and a wave staggered round table cooling flow field (WSRTCFF). This study systematically investigates the effects of WSRTCFF presence or absence, flow direction, velocity, and inlet temperature on heat and mass transfer as well as PEMFC performance. The results show that introducing WSRTCFF significantly improves temperature distribution in the flow field. Compared to hydrogen flow direction, oxygen flow direction not only effectively mitigates local hot spot effects but enhances current density by 12.55 % compared to no cooling. When coolant flow velocity is below 0.1 m/s, increasing velocity promotes system heat dissipation, enhancing working efficiency and cell stability. However, when velocity exceeds 0.1 m/s, the change in the flow velocity has minimal effect on PEMFC performance. Furthermore, comparative analysis of different coolant temperatures indicates that at 333.15 K, maximum temperature remains below 348.2 K, maintaining membrane hydration and achieving a good balance of substances, temperatures, and performance.

Mesoporous PtIr alloy single-particle: A novel SECM-tip for in situ monitoring NO of single-cell

As a vital factor in cell metabolism, nitric oxide (NO) is associated with nitrosative stress and subsequent inflammations and diseases. In situ, real-time NO monitoring is challenging due to its relative trace concentration and fast diffusion in cell. Scanning electrochemical microscopy (SECM) is suited uniquely for single-cell analysis, and its electrochemical response to targets can be further enhanced by improving the interfacial properties of its tip. Here, an ultramicroelectrodes (UMEs) modification strategy based on bimetallic single-particle was proposed for the first time. This mesoporous platinum/iridium alloy single-particle (mPtIr SP) interface using micelle-assisted electrodeposition was characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). And the nucleation kinetic progress which can be defined as "oil-in-water-like" electrodeposition was discussed in detail. The high sensitivity (203.86 μA/μM·cm2) and good selectivity for NO detection benefits from the high catalysis of the PtIr alloy and the high mass transfer properties of the porous interface. In particular, this novel UME can real-time monitor NO release from a single MCF-7 cell stimulated by perfluorooctanoic acid (PFOA), providing new ideas for contaminant toxicity assessment, health diagnostics, and disease treatment.

Comparative numerical study between MHD Forchheimer nano and hybrid nanofluid flows over stretching sheet under aligned magnetic field in the presence of radiation absorption

ABSTRACT This study investigates the mass and heat transfer properties of Ag-H2O nanofluid MHD Forchheimer flows and Ag-MoS2/H2O hybrid nanofluid over two-dimensional linear stretching surfaces in aligned magnetic fields with absorption of radiation. The fluid experiences rotational motion around the vertical axis at a consistent angular speed. The system of nonlinear ODEs is derived from the set of nonlinear PDEs by use of similarity transformations. The BVP-5C shooting approach in MATLAB is then employed to solve the associated system of ODEs. As the Forchheimer number, porosity parameter, rotation parameter and aligned magnetic field exhibit an ascent, the velocity profile along the x-axis and y-axis experiences a decrement. Simultaneously, an augmentation in the magnetic parameter, thermal radiation and rotation parameter induces a heightened temperature profile. Additionally, greater values of the Forchheimer number, rotation parameter and magnetic parameters correspond to an increase in concentration profile. Furthermore, the results indicated an increased temperature profile in the Ag-MoS2/H2O hybrid nanofluid compared to that in the Ag-H2O nanofluid for magnetic, rotation and radiation parameters. Also, the concentration profile of magnetic and rotation parameters along with the Forchheimer number were noted to be higher in the Ag-MoS2/H2O hybrid nanofluid compared to that in the Ag-H2O nanofluid.

Modelling of a mechanically enhanced PTFE-PVC composite polymer inclusion membrane for highly selective separation of several transition metal ions

Conventional polymer inclusion membranes (PIMs) exhibit suboptimal mechanical properties. Consequently, new composite PIMs were prepared by a modified solvent evaporation method using a PTFE base membrane, a PVC polymer, and an organic phosphonate extractant. Their chemical compositions and microstructures were analyzed by ATR-FTIR and FESEM. The mechanical and mass transfer properties of the composite PIMs were systematically investigated. The composite PIMs exhibited significantly higher tensile strength (36.86 MPa to 52.77 MPa), reduced tensile strain (76.49 % to 118.49 %), and enhanced bursting strength exceeding 0.2 MPa, compared to conventional PIMs. The Zn2+/Cu2+ were separated with a high separation coefficient of 2003.19 by a retardant-enhanced composite PIM system. A new mass transfer model was developed by analyzing the multilayered structure of composite PIMs in depth. The apparent diffusion coefficient of Zn2+ within PTFE-PVC composite layer (7.76 × 10−14 m2/s) was found to be lower than that within polymer inclusion layer (3.18 × 10−13 m2/s). The optimal regions of polymer inclusion layer thickness, contact area, and time were selected by model calculation for a certain separation task (e.g., purity ≥ 0.97 and yield ≥0.80 for Zn2+ or Cu2+). Finally, the retardant-enhanced composite PIMs were successfully used for selective separation of several other transition metal ions.

MHD Stefan Flow of Casson Nanofluid Complete a Porous Medium in The Presence of Chemical Reaction with The Effect of Thompson as Well as Troian Slip Over a Plate in the Company of Radiation

In this work, we report the effects of Thompson, Troian slip, and Stefan blowing on the magnetohydrodynamic (MHD) Cassonnanofluid behavior via a porous media while a chemical reaction is taking place. We also examine the effects of radiation parameters, Joel heat, and velocity distribution using a two-phase model for nanofluids. Similarity transformations may be used to convert the primary Partial Differential Equations (PDEs) into Ordinary Differential Equations (ODEs). MATLAB Shooting and Runge-Kutta algorithms may be used to solve nonlinear equations. The variations in non-dimensional parameters show the effects on mass transfer, heat, and fluid flow properties. It is shown that the skin friction coefficient falls as the Stefan blowing parameter S increases. As the values of the Thompson and Troian slip parameters increase, the fluid concentration decreases. With an increase in Nt, Nb, and k, the fluid's heat rises but its concentration falls. The results of this analysis provide several enticing aspects that are going to give merits for further study of the problems.