Pore Radius Research Articles

Interleaflet Translocation of Second-Harmonic-Generation-Active Dye Molecules in Phospholipid Bilayers with Transmembrane Pores.

Second harmonic generation (SHG) measurements using SHG-active dye molecules have recently attracted attention as a method to detect the formation of pores in phospholipid bilayers. The bilayers, in which the dye molecules are embedded in the outer leaflet, exhibit a noncentrosymmetric structure, generating SHG signals. However, when pores form, these dye molecules translocate through the pores into the inner leaflet, leading to a more centrosymmetric structure and the subsequent loss of the SHG signals. A decrease in the SHG signals has been experimentally observed in membranes subjected to electrical stimuli. However, the characteristics of the interleaflet translocation of SHG-active dye molecules through pores remain unclear, hindering quantitative estimation of the membrane conditions, such as the pore size and density, based on the SHG signal reduction. In this study, we investigated the interleaflet translocation characteristics of Ap3, an SHG-active dye molecule, using molecular dynamics (MD) simulations and two-dimensional random-walk (RW) simulations. The MD simulations revealed that Ap3 molecules only translocate between the leaflets along the pore sidewalls. We determined the lateral diffusion coefficient of Ap3 within the membrane plane and its propensity for interleaflet movement at the pore wall. Based on these movement characteristics, the RW model successfully reproduced the characteristic time scale of the interleaflet translocation observed in the MD simulations. By varying the pore size and density in the RW simulations, we estimated that the characteristic time scale of interleaflet translocation depends on the -0.31 power of the pore radius and the -1.13 power of the pore density. Using these findings, we estimated the number of pores that probably formed in membranes during previous electroporation experiments. These results indicate the potential of optical measurement of the dye molecule movement for the indirect quantitative estimation of the pore size and number, which are challenging to measure optically.

Mechanistic Modelling for Optimising LTES-Enhanced Composites for Construction Applications

This study addresses the optimisation of latent heat thermal energy storage (LTES) composites for construction applications by utilising mechanistic modelling. The work focuses on enhancing the performance of phase change materials (PCMs) incorporated into expanded perlite (EP) for building energy efficiency by delivering sorption capacity models analysing factors such as particle size, surface area, and pore volume, particularly highlighting the performance of EP as a PCM carrier due to its high porosity (around 90%) and large surface area (up to 20 m2/g), which allowed for improved energy storage density and heat transfer. Key challenges in the integration of PCMs into construction materials, such as limited thermal conductivity and leakage during phase transitions, are explored. The model evaluates key parameters affecting sorption, such as temperature, pressure, and surface characteristics of the materials. The results indicate that while higher temperatures enhance sorption in larger pores, they reduce efficiency in smaller ones, leading to a slight overall decrease in total sorption capacity at elevated temperatures. The sorption capacity of water is a value slightly above 2 kg/kg EP, while the PCM RT27 exhibits a sorption capacity of 0.59 kg/kg EP. These results represent the optimised sorption performance in terms of temperature between 40 °C and 50 °C. Furthermore, applying vacuum impregnation is investigated in relation to the pore radii of the EP particles. Larger pore radii show a noticeable improvement in overall sorption capacity from 0.59 kg/kg EP to 0.68 kg/kg EP as pressure increases, especially beyond 4 × 105 Pa. The contribution of inter-particle sorption remains stable, while the intra-particle sorption in large pores drives the overall capacity upward. The findings convey significant findings in optimising the design of LTES-enhanced composites for improved energy storage, thermal regulation, and structural integrity in building applications.

Formulation Factors Affecting the Formation of Visible-Bubbles During the Reconstitution Process of Freeze-Dried Etanercept Formulations: Protein Concentration, Stabilizers, and Surfactants.

Freeze drying is one of the common methods to extend the long-term stability of biologicals. Biological products in solid form have the advantages of convenient transportation and stable long-term storage. However, long reconstitution time and extensive visible bubbles are frequently generated during the reconstitution process for many freeze-dried protein formulations, which can potentially affect the management efficiency of staff, patient compliance, and product quality. The reconstitution time has been extensively studied, but the influence of the formulations on the formation of visible bubbles is often overlooked. This paper investigated the effect of freeze-drying formulation factors (i.e., protein concentrations, surfactant concentrations, and sucrose/mannitol compositions) on product stability and visible bubbles generated during reconstitution of freeze-dried etanercept formulations. The generating and breakup mechanisms of visible bubbles were detected via internal microstructure of cake, surface tension, and viscosity measurement. Under the same protein concentration, the formulation of mannitol mixed with sucrose in a weight ratio of 4:1 produces fewer visible bubbles during the reconstitution process compared to the formulation of sucrose with the same total mass. This has been proven to be due to the large number of smaller radius pores distributed in the pores of the freeze-dried cake of the former, while the average internal structure pores of the latter are much larger than those of the former. As an amorphous stabilizer, sucrose can ensure the long-term stability of protein and greatly reduce the generation and maintenance of foams in the reconstitution process, making it a more robust excipient for freeze-dried protein formulations.

Thermodynamic Sorption Study of a Medicinal Plant Using the Standard Static Gravimetric Method for a Better Conservation

Aromatic and medicinal plants are a natural source of pharmaceutical compounds with curative and therapeutic properties. They have been used for centuries to treat various ailments and offer alternative options to conventional treatments. Among these plants, Marrubium vulgare L., which is widely used in traditional medicine for diabetes treatment, has antioxidant potential as well as anti-inflammatory, healing, and soothing properties, attracting increasing medical interest. In this context, the hygroscopic behavior of Marrubium vulgare L. is reported. The adsorption-desorption isotherms of Marrubium vulgare leaves were determined using the standard static gravimetric method at three temperatures (30, 40, and 50 °C) to ensure physicochemical and microbiological stability throughout the storage process. The results showed that the adsorption-desorption isotherms of all samples followed a sigmoidal pattern, consistent with other agricultural products discussed in the literature. The optimal moisture content for conservation was also determined. The GAB (Guggenheim-Anderson-de Boer) and double polynomial models were the most suitable for describing the sorption curves. The adsorption-desorption data were examined to determine the moisture content of the monolayer (3.4-9.7%), properties of sorbed water in porous structures and surfaces, total heat of wetting, net isosteric heat of sorption, spreading pressure, differential entropy, and enthalpy-entropy compensation. It was also observed that the spreading pressure and average pore radius increase with rising relative humidity and temperature, leading to the appearance of defects on the surface of Marrubium vulgare leaves. Compensation theory is essential to consider when evaluating the impact of temperature on the adsorption-desorption properties. The Gibbs free energy was positive for sorption, indicating that the process is non-spontaneous.

Slip Flow in Hydrophilic Nanopores of Silica Colloidal Crystals.

Slip flow, a fluid flow enhanced in comparison to that calculated using continuum equations, has been reported for many nanopores, mostly those with hydrophobic surfaces. We investigated the flow of water, hexane, and methanol through hydrophilic nanopores in silica colloidal crystals. Three silica sphere sizes were used to prepare the crystals: 150 ± 30, 500 ± 40, and 1500 ± 100 nm. The spheres were pressure-packed in a fused silica capillary with an inner diameter of 75 μm. The resulting colloidal crystals had an average pore radius of 18 ± 4, 66 ± 6, and 215 ± 14 nm for the three silica sphere sizes used. The colloidal crystals were demonstrated to possess almost perfect packing. The fluids were flown through the colloidal crystals, and the pressure drop was measured using a pressure transducer. The flow rates varied from 10 to 80 nL/min. Water showed no-slip Hagen-Poiseuille flow with no enhancement for all of the pore sizes. Hexane showed a 20-fold flow enhancement for the smallest pore size, and the enhancement diminished for the medium pore size and was absent for the largest pore size. Methanol also showed a 20-fold flow enhancement for the smallest pores, about a 15-fold enhancement for the medium pores, and no enhancement for the largest pore size. The reduction in flow enhancement was significantly steeper for hexane than for methanol with an increasing pore size. These results demonstrate a significant slip flow in small (15 nm) hydrophilic nanopores for non-wetting fluids, which is size- and fluid-property-dependent. These observations are important for understanding fluid dynamics in liquid chromatography and naturally occurring nanoporous media.

Time-varying quantitative characterization of reservoir microscopic pore structure based on digital core

The reservoir physical parameters (such as porosity, permeability, phase permeability, etc.) will change in the process of water injection development with the continuous flushing effect of high magnification water drive, which may have adverse effects on development if they cannot be accurately characterized. In this paper, we try to quantitative characterize the time -varying features of pore structure from the microscopic perspective. We used high-resolution 3D micro-CT (MCT) images to supplement the analysis of the physical properties of the rocks, and we used 3D pore network modeling technology to generate a 3D model of the rock samples. Then the relevant static micro-pore parameters are derived to study the changes of rock properties in different periods of development. Pore parameters were obtained to study the changes in porosity, permeability and pore size distribution of the rocks under different expulsion multiples, and to visualize the time-varying pattern of the microstructure of the rock samples under different stages of water injection. Under low-multiple water-driven conditions (10 PV), the physical properties of the rock samples did not change significantly, with an average facies change of only 1.98%. When reaching high multiples of water drive (more than 500PV), the change rate reaches more than 15%. And with the increase of water drive multiples, the distribution of pore radius and throat radius of rock samples showed an obvious right-shift trend, and the pores and throats increased, which was consistent with the results of CT scanning photographs. Equation fitting of the simulation results reveals that the core micro-parameters show an overall logarithmic relationship with the change of water drive. In this paper, a new application of Micro CT is provided to quantify the microstructure of water-injected reservoirs. By adopting this method, the effect of water-drive multiplicity on reservoir structure can be illustrated from a microscopic perspective. Meanwhile, compared with previous studies, this paper further investigates the effect of time-variation based on the qualitative analysis of the effect of time-variation of water-driven in reservoirs, and regresses time-variation curves and formulas through the changes in multiple water-driven states, which fills in the gap of the current lack of quantitative research and provides new understanding and optimization of the development of oilfields. The study will provide a new perspective for understanding and optimizing oilfield development.

Controlling the synthesis conditions for the fabrication of Pb (Mg1/3Nb2/3) O3 nano powders to diminish undesirable pyrochlore structure

The main problem in fabrication of relaxor lead magnesium niobate (PMN; Pb(Mg1/3Nb2/3) O3) material is the formation of an undesirable pyrochlore phase (Pb1.86Mg0.24Nb1.67O6.5). This phase significantly impacts the electrical properties of the compound. Therefore, this article presents various experimental trials performed to minimize the formation of the undesirable pyrochlore phase during the preparation of relaxor lead magnesium niobate material. In this regard, a sol-gel pathway was utilized. The synthesis was conducted as follows; niobium ethoxide, metal nitrate and metal acetate were combined with 2-methoxyethanol to form transparent solution. The gel was then formed by heating the solution at 80 °C, to form the precursor powder. Subsequently, thermal treatment at elevated temperatures was performed to form the perovskite structure. The effects of several synthesis conditions such as the presence of surplus Mg2+ ions, excess of Pb2+ ion content, annealing and pre-annealing temperature, type of fuel and the annealing time, on the physicochemical properties and the structure of PMN phase were investigated. Thermal gravimetric analysis (TGA) results manifested that crystallization of PMN was occurred at a temperature of 580 °C. X-ray diffraction (XRD) profiles revealed that the ratio of the pyrochlore (Pb1.86Mg0.24Nb1.67O6.5) phase was significantly reduced by increasing the Mg2+ ion content up to 30%. The lowest concentration of the pyrochlore phase was predestined during a single annealing step at 900 °C for a period of 3 h, using an excess of 30% Mg2+ ion concentration. Rietveld refinement of the XRD data was conducted using Material Analysis Using Diffraction (MAUD) software. The refinement was performed to determine the crystal structure and lattice constants. From the refinement, the cubic structure was evinced with a lattice constant (a) of 4.048Å. Fourier transform infrared (FT-IR) spectroscopy of PMN nano powders annealed at 900 °C for 3 h demonstrated a spectrum characteristic of the most perovskite compounds with a common BO6 oxygen-octahedral structure. Additionally, X-ray photoelectron spectrum (XPS) provided the composition and the chemical states of the prepared PMN compound. Brunauer–Emmett–Teller (BET) surface area analysis revealed that the PMN material exhibited a large specific surface area (155.8 m2/g) with a small average pore radius (2.8 nm). High-resolution transmission electron microscopy (HR-TEM) images indicated that the PMN particles manifested a regular cubic structure with an average particle size of 43 ± 0.1 nm under the optimum conditions. The selected area electron diffraction (SAED) technique proved the polycrystalline nature of the formed ceramic material. From characterization results obtained in this work, this material shows potential candidate for various metrological applications, including piezoceramic for the ultrasonic transducer cores.

Optimization and characterization of physicochemical, morphological, structural, thermal, and rheological properties of microwave-assisted extracted pectin from Dillenia indica fruit.

Microwave-assisted extraction of pectin from Dillenia indica (DI) fruit was optimized using Box-Behnken design to maximize yield and quality. Parameters such as solid:solvent (1:10-1:30), microwave power (200-600W), and extraction time (4-10min) were varied to determine the optimal conditions. Through experimentation, the optimized extraction parameters were identified as 1:23.66 solid:solvent, 400W microwave power, and 7min of extraction time, under which the predicted yield and equivalent weight were 19.68% and 915.93, respectively. The optimized conditions were validated experimentally (yield:19.4±0.35%) and equivalent weight:914.57±0.62), showing close agreement with predicted values. Physicochemical properties of the extracted pectin were determined, revealing an effective pore radius of 0.263±0.005mm and a swelling index order of: water(1)>pH6(0.7)>HCl(0.3). Moisture content was measured as 7.23±0.25%, while ash content was found to be 2.23±0.25%. Further analysis included the determination of methoxyl value, anhydrouronic acid content, degree of esterification, and protein content, which were 9.61±0.31%, 73.56±1.86%, 74.15±0.28%, and 1.16±0.16%, respectively. Monosaccharide composition revealed presence of neutral sugars, glucose, arabinose and rhamnose and molecular weight was 71,489g/mol. Morphological characteristics, assessed using scanning electron microscopy, showed a rough, irregular surface of DI fruit pectin. Fourier-transform infrared spectroscopy (FTIR) indicated similarity to standard high methoxyl pectin, while nuclear magnetic resonance (NMR) confirmed characteristic functional groups. Thermal behaviour, determined via differential scanning calorimetry (DSC), exhibited endothermic and exothermic transitions at 83.6°C and 260.027°C, respectively. Rheological and functional properties revealed DI fruit pectin solution as a non-Newtonian fluid with shear thinning behaviour, forming weak gels and that its emulsion capacity increased with increase in pectin concentration. Overall, this study provides a comprehensive characterization of microwave-assisted extracted pectin from Dillenia indica fruit, offering insights into its potential applications in food industries.

Fabrication and Characterization of PPSU/PES Blend Nanofiltration Membrane via VIPS‐NIPS Method for Effective Dye Rejection

ABSTRACTIndustrial effluents, including dyes, pose a threat to the environment and human health, as they are resistant to reacting with oxygen; therefore, they are rarely biodegradable. Among the various processes, nanofiltration is an attractive process for separating dyes from water due to its economic efficiency. This work represents the fabrication of poly (phenyl sulfone) (PPSU)/poly (ether sulfone) (PES) blend nanofiltration membranes through vapor‐induced phase separation (VIPS) followed by immersion precipitation. The influence of polymer blend, exposure time, and coagulation bath composition on membrane characteristics and performance was studied. Results illustrate that an increment in exposure time caused a thinner top layer and changed the cross‐section morphology from finger‐like to sponge‐like. At PPSU:PES = 50:50 blend ratio, the pore radius significantly got larger than the neat polymers' fabricated membranes. The addition of N‐methyl‐2‐pyrrolidone (NMP) in the coagulation bath causes the formation of smaller finger‐like voids at the top layers and a sponge‐like structure in the sub‐layers of membranes. The optimal conditions for the nanofiltration membrane were determined at 28 s VIPS time, an equal ratio of polymers, and pure water as the coagulation bath. Under these conditions, the distilled water permeability and Rose Bengal rejection were determined as 63.6 L/m2 h and 77.11%, respectively.

Study on the Microstructure and Permeability Characteristics of Tailings Based on CT Scanning Technology

The permeability characteristics of tailings directly affect the position of the infiltration line of the tailings dam, which is the most critical factor affecting tailings dam failures. In order to fully analyze the essence of its permeability characteristics, computed tomography (CT) technology is used to analyze the structure of different types of tailings from a microscopic perspective and carry out microscopic seepage simulation. The results showed the following findings: (1) The porosity of viscous tailings ranges from 25 to 35%, the distribution of surface porosity along the height is relatively uniform, and the distribution is shown as having a certain discrete nature with the increase in particle size. (2) Compared with silty and sandy tailings, the surface of viscous tailings is smoother and more round, and the shape factor can reach 0.95; (3) The data gap between the simulation and the measurements by CT scanning technology is less than 10%, and the estimation of the permeability characteristics is feasible, with good applicability in the simulation of tailings seepage. (4) In the microscopic pore throat structure, the permeability characteristics of the tailings are more affected by the radius of the throat than the pore radius, and the exponential function relationship between the permeability coefficient and the porosity satisfies a high correlation. In this paper, the relationship between the microstructure and permeability characteristics of tailings is analyzed by CT technology; the permeability is simulated and calculated, and a permeability coefficient prediction model for tailings is proposed in combination with the experiment, which can provide a new idea and method for the study of the permeability characteristics of tailings.

Characteristics of Three-Dimensional Pore-Fracture Network Development and Enhanced Seepage Heat Transfer in Hot Dry Rock Stimulated by Temperature Shock Effects.

Hot dry rock (HDR) geothermal is a sustainable and clean energy source. However, its development progress is hindered by creating seepage channels in deep reservoirs with low porosity and permeability. Traditional hydraulic fracturing techniques are ineffective for enhancing the permeability of these high-strength reservoirs. To address this, a cyclic nitrogen injection technique was proposed, which leverages the thermal gradients of the hot reservoir to stimulate a complex thermally induced fracture network. To study the three-dimensional pore-fracture structure and the flow characteristic of HDR under temperature shock effects, various high-temperature rock samples (200-500 °C) were treated with 5 cycles of liquid nitrogen cold shock. Using digital core technology, a visual pore-fracture network was reconstructed and the simulation of flow and heat exchange within this network was further performed. The main conclusions are as follows: Following the liquid nitrogen cold shock treatment with rock cores of 200-300 °C, only a few isolated micropores were formed, marked by low porosity and poor connectivity, yielding effective porosities of 0.79 and 1.52%, respectively. In contrast, the cold shock at 400-500 °C induced the formation of a reticulated pore-fracture network. This development was attributed to the combined effects of thermal stress and grain expansion, with an effective porosity reaching 12.58%. Further, a pore network model revealed a substantial increase in both the pore number and size, especially under the cold shock of 500 °C cores, where the largest pore radius reached 2133 μm. The permeability of the representative elementary volume increased significantly with the rising cold shock temperature difference, escalating from 13.79 μm2 at 200 °C to 1101.39 μm2 at 500 °C. This shift signifies a transition from localized to more extensive flow paths. Based on the actual pore-fracture network, a simulation of heat extraction from HDR was conducted, showing that the exchanged heat increased from 4.51 × 10-8 to 8.34 × 10-8 W with the rise in the temperature difference. Within the temperature range of 300-400 °C, a singular flow path was observed, characterized by minimal fluid transport but elevated exit temperatures. Meanwhile, at 500 °C, a superior heat exchange network was established, featuring improved fluid transport and heat exchange efficiency.

Synthesis and characterization of novel magnetic metal organic framework for efficient removal of ketoprofen from aqueous solutions: Mechanism of interaction, adsorption and optimization via BOX-Behnken design

This investigation examines the adsorption and elimination of the anti-inflammatory medication ketoprofen (KTP) in relation to a newly developed magnetic thorium metal-organic framework (MTh-MOF). The study found that KTP absorption on MTh-MOF resulted in a reduction in pore volume, pore size, and surface area, as revealed by N2 adsorption/desorption isotherm analysis used to evaluate the characteristics of the MTh-MOF. Scanning electron microscopy (SEM) showed that the pore radius of MTh-MOF decreased from 1.68 nm to 0.82 nm, demonstrating a consistent and uniform structure. Fourier-transform infrared (FT-IR) spectroscopy was employed to identify the functional groups present in MTh-MOF, while X-ray photoelectron spectroscopy (XPS) was used to confirm the compound's structure. The optimal conditions for achieving a high adsorption capacity were found to be at pH 6 and a MTh-MOF dose of 0.02 g. The results indicated that MTh-MOF displayed a high capacity for absorbing KTP, with the adsorption data fitting well with pseudo-second-order kinetic models and the Langmuir isotherm. The adsorption capacity of MTh-MOF for KTP was determined to be 518 mg/g. The adsorption energy of 28.26 kJ·mol–1 suggested that chemisorption was the predominant mode of adsorption. The process of KTP adsorption on MTh-MOF was observed to be spontaneous, endothermic, and random, as evidenced by the temperature-dependent increases in the thermodynamic parameters (ΔGo, ΔHo, and ΔSo). The adsorption process was optimized using Response Surface Methodology and Box-Behnken design (RSM, BBD). Aromatic rings interact via π-π bonding, while chemisorption involves the development of chemical interactions between the adsorbate and adsorbent. Additionally, electrostatic interactions arise from the attraction or repulsion of charges between the adsorbate and adsorbent, and pore-filling occurs when the adsorbate fills the adsorbent's pores. In order to understand the electrical properties, reactivity, and shape of KTP, density functional theory (DFT) was utilized.

Polyelectrolyte brush in a cylindrical pore: A Poisson-Boltzmann theory.

The conformation of a polyelectrolyte (PE) brush grafted to the inner surface of a long cylindrical mesopore was described within analytical Poisson-Boltzmann strong stretching approximation. The internal structure of the PE brush, including brush thickness and radial density profile of monomer units, and radial distribution of electrostatic potential were analyzed as functions of the pore radius, degree of polymerization, and grafting density of the brush-forming PE chains as well as ionic strength of the solution. It is demonstrated that narrowing of the pore leads to a non-monotonous variation of the brush thickness, which passes through a maximum when the brush thickness becomes equal to the pore radius. Variation in the salt concentration triggers conformational transition that leads to the opening or closing of the hollow (PE-free) channel in the pore center that potentially allows controlling of the pore-selective permeability for charged nanocolloidal particles (e.g., globular proteins or viruses). The predictions of the analytical theory were validated by numerical calculations using the Scheutjens-Fleer self-consistent field modeling method. These theoretical findings may be used for the design of highly selective smart mesoporous membranes with PE brush-functionalized pores for, e.g., protein separation and purification.

Activated Charcoal Magnetic Composite from Jengkol Peels as An Efficient Adsorbent for Aquatic Antibiotic Removal: An in Vitro Study

Antibiotic resistance has become a global issue that is quite worrying because it can threaten the survival of living things, especially humans. This resistance can occur due to the inappropriate use of antibiotics by the community. This study aims to determine the ability of activated charcoal magnetic composites (ACMC) to adsorb tetracycline hydrochloride compounds. Samples were obtained from jengkol peel waste which was charred and activated using acid and the addition of magnetic properties. The more PbFe2O4 added to activated charcoal, the greater the magnetic properties, surface area, pore-volume, and pore radius. The results showed that a type of IV adsorption isotherm which is a characteristic of mesoporous materials with a pore size of 2.0892 nm. The addition of magnetic properties to activated charcoal increase 29.33% the amount of tetracycline that is adsorbed by the adsorbent with optimal absorption in alkaline conditions. The adsorption process followed the adsorption kinetics of Ho and the Freundlich adsorption isotherm with an adsorption capacity of 76.3359 mg/g. ACMC material can potentially be one of the adsorbents that can reduce contamination of tetracycline hydrochloride antibiotics in the aquatic environment so that antimicrobial resistance can be minimized. Keyword: acidity, agricultural waste, carbonization, functional Group, VSM analysis

Separation of Antibiotics Using Two Commercial Nanofiltration Membranes-Experimental Study and Modelling.

The widespread use of antimicrobial drugs has contributed to the increasing trace levels of contaminants in the environment, posing an environmental problem and a challenge to modern-day medicine seeking advanced solutions. Nanofiltration is one such breakthrough solution for the selective removal of antibiotics from wastewater due to their high efficiency, scalability, and versatility. This study examines the separation of antibiotics (sulfamethoxazole (SMX), trimethoprim (TMP), and metformin (MET), respectively) using commercially available membranes with an emphasis on AFC membranes (AFC 30 and AFC 80). Thus, we evaluate their efficacy, performance, and applicability in wastewater treatment processes. The data for characterizing the structural parameters of the NF membranes were determined from an uncharged organic solute rejection experiment, and the effect of various operating conditions on the retention of solutes was evaluated. All experimental data were collected using a laboratory-scale nanofiltration unit and HPLC, and rejection percentages were determined using analytical measurements. The results obtained allowed for the determination of the radius of the membrane pores using the Steric Hindrance Pore (SHP) model, resulting in values of 0.353 and 0.268 nm for the AFC 30 and AFC 80 membranes, respectively. Additionally, higher transmembrane pressure and feed flow were observed to lead to an increased rejection of antibiotics. AFC 30 demonstrated a rejection of 94% for SMX, 87% for TMP, and 87% for MET, while AFC 80 exhibited a rejection of 99.5% for SMX, 97.5% for TMP, and 98% for MET. The sieving effect appears to be the primary separation mechanism for AFC 30, as lower feed-flow rates were observed to intensify concentration polarization, thereby compromising rejection efficiency. On the contrary, AFC 80 experienced less concentration polarization due to its smaller pore sizes, effectively preventing pore clogging. Membrane performance was evaluated using the Spiegler-Kedem-Katchalsky model, based on irreversible thermodynamics, which effectively explained the mechanism of solute transport of antibiotics through the AFC 30 and AFC 80 membranes in the NF process.

Effect of Salt Bridge Formation on Proton Transport in CNTs

Various sectors have initiated technology development projects aimed at realizing a hydrogen-based society with low carbon dioxide (CO2) emissions. A proton (H+) transfer system with high permeability and selectivity is essential for the hydrogen infrastructure and fuel cells that support a hydrogen-based society. Therefore, intensive research is underway to design bioinspired artificial proton channels. Natural proteins achieve high proton selectivity by organizing proton-conducting pathways with scattered ionizable side chains and controlling proton transport through Vehicle and Grotthuss mechanisms. The Hv1 channel is a proton-selective protein that contains the amino acids aspartic acid (Asp) and arginine (Arg) in its pathway. As shown in Figure 1, the proton transport mechanism of Hv1 channels is suggested that Asp and Arg can be protonated, allowing them to transport protons via the Grotthuss mechanism. Additionally, Asp and Arg form salt bridges to close the pathway, thereby inhibiting the transport of other ions via the vehicle mechanism. However, the relationship between Asp and Arg and their impact on the transport mechanism remains unclear. It is important to elucidate the relationship between the inhibition of transport and pore size, as well as to understand the correlation between the inhibition of transport and salt bridges, to install proton transport mechanism of Hv1 channels into artificial proton channels. In this study, carbon nanotubes (CNTs) were used as a model pore for artificial ion channels, and we analyzed the effects different sizes of CNTs modifying with Asp and Arg on ion transport properties using molecular dynamics simulations.We adopted the armchair CNTs model shown in Table 1, using the CNTs chirality (5,5), which is known to spontaneously fill with water at room temperature, as the smallest model. For the molecular models of Asp and Arg, side chain models of Asp(N)–Arg(N) and Asp(-)– Arg(+) pairs, which can form salt bridges, were modified inside CNTs.The results of the probability of hydrogen bond formation are shown in Figure 2. The results confirm that hydrogen bonds are always maintained at a pore radius R = 4.75 Å (CNTs chirality = 7,7) for both conditions. As the distance between Asp and Arg increases with increasing pore radius R above R = 4.75 Å, it appears that the hydrogen bonds cannot be maintained. Even when the pore radius is smaller than R = 4.75 Å, the probability of hydrogen bonding formation decreases. In the poster, we will present further structural analyses, such as the orientations of Asp and Arg and their relation to the hydronium ion conformation.[1] Dudev, T., Musset, B., Morgan, D. et al. Selectivity Mechanism of the Voltage-gated Proton Channel, HV1. Sci Rep 5, 10320 (2015). Figure 1

High Spatial Resolution Neutron Imaging of Lithium-Ion Batteries: Correlating Microstructure and Lithium Transport

With the increasing desire for fast charging capabilities in lithium-ion batteries due to the popularity of electric vehicles, research has recently been focused on increasing energy and power density while simultaneously revealing the need for improved safety mechanisms and decreased overall cost. In response to this need, interest in thick battery electrodes has increased. By increasing the active material per unit area within the electrode, the energy density is increased due to minimization of current collectors, separators, and other packaging components. However, increasing the thickness of electrodes introduces new challenges, including charge-transport limitations.To successfully address the desired increase of energy density and capability of fast charging, high spatial resolution in operando neutron radiography (nR) was utilized to better understand the correlation between microstructure and lithium transport of ultra-thick electrodes. This allows for a comparison between the electrochemical processes occurring during cycling and what is seen in neutron imaging, bridging the gap between microstructural observation and electrochemical testing. Two differing fabrication methods were used to prepare the cathodes and anodes: a solvent free method using a hydraulic press and a wet cast method using N-methyl-pyrrolidone solvent (NMP). The fabrication methods were purposefully chosen to yield differing electrode microstructures. The lithium-ion batteries used in this work were fabricated using graphite (graphite (90 wt%): carbon black (5 wt%): polyvinylidene fluoride (5 wt%)) anodes and NMC (Li(Ni0.8Mn0.1Co0.1)O2) (80 wt%): carbon black (10 wt%): polyvinylidene fluoride (10 wt%)) cathodes with a thickness of ~2.5mm and diameter of 10mm. A deuterated electrolyte (1M LiPF6 EC/DMC=30/70 (v/v)) was used in order to improve the attenuation of lithium within the electrodes. Custom cells were fabricated using PFA Swagelok components to avoid any unnecessary neutron attenuation during neutron radiography. High-resolution (7.5 µm pixel size) in operando nR was performed on these cells using the Multimodal Advanced Radiography Station (MARS) beamline at the Oak National Laboratory High Flux Isotope Reactor. High spatial resolution neutron tomography (nCT) was performed on a cycled battery following in operando nR.Comparing changes in the attenuation coefficient for both a solvent free anode and wet cast anode reveals distinct lithiation patterns in each electrode. In the solvent free sample, there is a dense, but thin, lithium rich region near the separator. In the wet cast sample, the lithium distribution is more evenly dispersed through the thickness of the electrode. The difference in distribution is likely due to the different average pore size of the samples, as represented by the size distribution of macroscopic porosity (pore radius > 20 µm) observed from high resolution nCT. From a comparison of the macroscopic pore radius for each fabrication method it is clear that the solvent free method yields smaller pores and an increased number of pores, whereas the wet cast method yields larger pores and a decreased number of pores. Results from in operando nR during electrochemical cycling and ex situ high spatial resolution nCT on cycled electrodes show that lithium distributions and plating risks are shown to be controlled by both the macroscopic structure of the electrodes and the network of pores and microscale active areas that support electrochemical reactions. This research used resources at the High Flux Isotope Reactor, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory.

Pixel Imaging Method, Transport Phenomenon in Sizes From Nano, Micro, and Milli Scale Pore Membrane

ABSTRACTIn this article, we develop NanoSoft SoftLab GUI circuit model and oscillator model to study the current–time and current–voltage characteristics inside the nanopore membrane. We study the ion transport for silicon nitride sputtered with silicon dioxide (Si3N4–SiO2) nanopore membrane, graphene, and molybdenum disulfide (MoS2) nanopore membrane. Further, we apply our two models to understand the ion transport in two polydimethylsiloxane (PDMS) micropore reservoirs connected in series with no nanopore membrane. Furthermore, we perform circuit simulations on silicon nitride sputtered with silicon dioxide with pore radius varying from nanometer to millimeter to obtain current from pA to μA. Here we develop NanoSoft visualization software to match the silicon nitride nanopore membrane. We develop open‐loop controller model to relate the ionic current in the nanopore to the nanofluidic calculator output. Our work can find applications for energy‐efficient nanofluidic processors and computers to build towards the recent nanofluidic memristive synapse‐like memory dynamics literature.

Controlling factors of fluid mobility in the tuff reservoirs of the Huoshiling formation, Dehui fault depression, southeastern Songliao Basin: insights from micro-nano pore structures

This study addresses the unclear understanding of the primary factors controlling fluid mobility in the tuff reservoirs of the Huoshiling Formation from the Dehui Fault Depression, southeastern Songliao Basin. Through physical property analysis, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), thin section (TS), pressure-controlled porosimetry (PCP), rate-controlled porosimetry (RCP), and nuclear magnetic resonance experiments (NMR) on ten tuff samples, we conducted a comprehensive and in-depth exploration of the influencing factors that control the mobility of reservoir fluids. The results indicate: 1) The primary mineral types in the tuff reservoirs are quartz, feldspar, and clay minerals, with porosity predominantly characterized by dissolution pores and intergranular pores; 2) Based on the morphology of PCP intrusion curves, the tuff samples from the study area can be categorized into three types, with reservoir quality progressively deteriorating from Type I to Type III; 3) Compared to the movable fluids saturation (MFS), movable fluids porosity (MFP) is more suitable for characterizing fluid mobility. The mobility of fluids is influenced by various factors such as mineral composition, physical property, pore-throat connectivity, pore type and heterogeneity. MFS and MFP show a positive correlation with permeability, the content of quartz and feldspar, median pore-throat radius (R50), average throat radius (ATR), average pore-throat radius ratio (APT), T2 cutoff value (T2-C), average throat radius (RT), sorting coefficient (SC), and intergranular pore dominate space (Inter-DS), while a negative correlation with the content of calcite and clay minerals, average pore-throat radius ratio, and the fractal dimension from NMR (DNMR). This study elucidates the influencing factors of fluid mobility in tuff reservoirs, which has important reference significance for the scientific development of this type of gas reservoir.

Effect of temperature on permeability of mudstone subjected to triaxial stresses and its application

In order to prevent leakage of pyrolysed oil and gas and the release of contaminants from the top and bottom strata, it is essential to carry out a comprehensive study of the seepage behaviour of these strata under high temperature triaxial stress conditions. The findings of this study will contribute to the development of effective strategies for the containment and integrity monitoring of subsurface reservoirs and storage environments. Mudstone, serving as both the upper and lower strata, offers an effective barrier due to its inherently low permeability. In order to explore the change rule of mudstone sealing performance under high temperature triaxial stress, an air-heated low permeability rock mass air permeability measurement system is used to measure the ground stress buried 500 m deep and the temperature variation characteristics of mudstone permeability on the roof and floor of Jimsar oil shale in Xinjiang under 100 °C. It was found that the permeability of stressed mudstone decreased with the temperature rising up to 100 °C. The primary factor influencing the outcome was the thermal expansion of the mudstone. The magnitude of the drop value was contingent upon the triaxial stresses that could potentially be induced by the application of significant tensile forces, resulting in a relatively minor drop value. The average hydraulic radius of pore in the mudstone was also calculated, which also exhibited continuous reduction as heating up to 100 °C and the degree of reduction could reach 68%. The capacity, that prevent oil & gas and contaminant from moving cross strata as a barrier, would be strengthened when the mudstone strata from roof and floor experienced the temperature low than 100 °C. The barrier performance of mudstone as a pollutant migration barrier layer to gas pollutant migration during in-situ heat injection mining of oil shale was further evaluated.