Pores Of Different Sizes Research Articles

Understanding the Wettability of C1N1 (Sub)Nanopores: Implications for Porous Carbonaceous Electrodes

AbstractUnderstanding how water interacts with nanopores of carbonaceous electrodes is crucial for energy storage and conversion applications. A high surface area of carbonaceous materials does not necessarily need to translate to a high electrolyte‐solid interface area. Herein, we study the interaction of water with nanoporous C1N1 materials to explain their very low specific capacitance in aqueous electrolytes despite their high surface area. Water was used to probe chemical environments, provided by pores of different sizes, in 1H MAS NMR experiments. We observe that regardless of their high hydrophilicity, only a negligible portion of water can enter the nanopores of C1N1, in contrast to a reference pure carbon material with a similar pore structure. The common paradigm that water easily enters hydrophilic pores does not apply to C1N1 nanopores below a few nanometers. Calorimetric and sorption experiments demonstrated strong water adsorption on the C1N1 surface, which restricts water mobility across the interface and impedes its penetration into the nanopores.

Understanding the Wettability of C1N1 (Sub)Nanopores: Implications for Porous Carbonaceous Electrodes.

Understanding how water interacts with nanopores of carbonaceous electrodes is crucial for energy storage and conversion applications. A high surface area of carbonaceous materials does not necessarily need to translate to a high electrolyte-solid interface area. Herein, we study the interaction of water with nanoporous C1N1 materials to explain their very low specific capacity in aqueous electrolytes despite their high surface area. Water was used to probe chemical environments, provided by pores of different sizes, in 1H MAS NMR experiments. We observe that regardless of their high hydrophilicity, only a negligible portion of water can enter the nanopores of C1N1, in contrast to a reference pure carbon material with a similar pore structure. The common paradigm that water easily enters hydrophilic pores does not apply to C1N1 nanopores below a few nanometers. Calorimetric and sorption experiments demonstrated strong water adsorption on the C1N1 surface, which restricts water mobility across the interface and impedes its penetration into the nanopores.

3D Nickel–Manganese bimetallic electrocatalysts for an enhanced hydrogen evolution reaction performance in simulated seawater/alkaline natural seawater

In this paper, we report an inexpensive one-step synthesis of self-supported 3D nickel-manganese (NiMn) bimetallic coatings and their application for the hydrogen evolution reaction in simulated seawater (1 M KOH + 0.5 M NaCl) and alkaline natural seawater (1 M KOH + natural seawater). These binary coatings were electrodeposited on a titanium substrate using a facile electrochemical deposition method by a dynamic hydrogen bubble template technique. The as-deposited NiMn coatings with variable Mn amounts produce typical globular and unique porous architecture with abundant pores of different sizes. The activity of these fabricated catalysts towards the hydrogen evolution reaction was investigated by linear sweep voltammetry towards simulated seawater and alkaline natural seawater at different temperatures. The surface morphology and composition of the catalysts were also characterized by scanning electron microscopy and inductively coupled plasma optical emission spectroscopy. The as-prepared NiMn/Ti electrocatalyst, which was electrodeposited using a chemical bath containing Ni2+ and Mn2+ ions with a molar ratio of Ni2+:Mn2+ = 1:5, exhibits excellent hydrogen evolution activity in simulated seawater with an ultra-low overpotential of 64.2 mV to reach a current density of 10 mA cm−2. It is noteworthy that this NiMn/Ti electrocatalyst also achieves a current density of 10 mA cm−2 in alkaline natural seawater with a comparably low overpotential of 79.3 mV. The current densities increase by ca. 1.75–2.35 times with an increase in temperature from 25 °C to 75 °C for hydrogen evolution in both electrolytes. This bimetallic catalyst has shown excellent long-term stability at a constant potential of −0.23 V (vs. RHE) and a constant current density of 10 mA cm−2 for 10 h, which ensures higher durability and robustness for practical application of seawater splitting technology.

Molecular insights into the impact of mineral pore size on methane hydrate formation

Natural gas hydrates are not only substantial energy sources but also have significant applications in the chemical industry and other fields. Although investigating hydrate formation in sediment minerals is crucial for their development and utilization, the underlying hydrate formation mechanism remains unclear. Here, molecular simulations were conducted in systems incorporating hydrophobic and hydrophilic pores of different sizes to investigate methane hydrate formation processes. The findings suggest that, as the hydrophobic slit size increases, there is a larger number of dissolved methane after the system reaches a metastable equilibrium state. The probability of cage formation indicates that hydrate cages readily form on hydrophobic surfaces or in the solution phase near the solution/gas interface. The larger slits are preferred for hydrate nucleation, regardless of whether the surface is hydrophobic, with most initial nuclei located near the liquid/methane interface. However, the interface perturbation can lead to the movement and growth of hydrate nuclei near the solution/methane interface into the bulk solution phase. Additionally, hydrate can nucleate and grow on the hydrophobic surface, facilitated by the adsorbed methane molecules and nonstandard cages. Pores hinder methane storage capacity in the hydrate phase due to the confinement effect and the amorphous nature of the hydrate formed. These molecular-level findings enhance our understanding of hydrate formation in sedimentary environments and porous materials, benefiting the development of natural gas hydrates and the use of porous materials for gas storage and transportation.

Saturation Equation: An Analytical Expression for Partial Saturation during Wicking Flow in Paper Microfluidic Channels.

The design and fabrication of paper-based microfluidic devices is critically dependent on modeling fluid flow through porous paper membranes. A commonly observed phenomenon is partial saturation, i.e., regions of the paper membrane not being filled completely due to pores of different sizes. The most comprehensive model to date of partial saturation during wicking flow in paper is the Richards equation. However, the solution to the Richards equation requires numerical solvers like COMSOL, which makes it largely inaccessible to the paper microfluidics and lateral flow assay community. There is therefore a need for a simple and appropriate model of partial saturation in paper membranes, easily usable by the wider research community. In the current work, we present an approach to model paper membranes as a bundle of parallel capillaries whose radii follow a two-parameter log-normal distribution. Application of the Washburn equation to the bundle provides a distribution of fluid fronts, which can be used to calculate saturation. Using this approach, we developed the "saturation equation"─an explicit analytical expression to calculate saturation as a function of space and time in 1D wicking flow. Experimentally obtained data for spatiotemporal saturation for four different paper materials were fit to this analytical model to obtain parameters for each material. Results obtained from this analytical model match well with both experimental data and numerical results obtained from the Richards equation. The availability of an explicit analytical expression for partial saturation will enable incorporation of the critical phenomenon of partial saturation in the design of paper microfluidic devices.

A preliminary in vivo and in vitro study of endothelial cell pyroptosis in the periodontal inflammatory environment

Objective: To observe whether endothelial cells undergo pyroptosis in the inflammatory periodontal environment by using a model in vivo and in vitro, providing an experimental basis for indepth understanding of the underlying pathogenesis of periodontitis. Methods: According to the classification of periodontal diseases of 2018, gingival tissues were collected from periodontally healthy subjects and patients with stage Ⅲ-Ⅳ, grade C periodontitis, who presented Department of Oral and Maxillofacial Surgery and Department of Periodontology, School of Stomatology, The Fourth Military Medical University from April to May 2022. Immunohistochemical staining was performed to detect the expression level and distribution of gasdermin D (GSDMD), a hallmark protein of cell pyroptosis, in gingival tissues. Periodontitis models were established in each group by ligating the maxillary second molar teeth of three mice for 2 weeks (ligation group). The alveolar bone resorption was determined by micro-CT (mice without ligation treatment were used as the control group), and the colocalization of GSDMD and CD31 were quantitatively analyzed by immunofluorescence staining in gingival tissues of healthy and inflammatory mice. Human umbilical vein endothelial cells (HUVECs) were cultured in vitro and treated with lipopolysaccharide (LPS) of Porphyromonas gingivalis (Pg) combined with adenosine triphosphate (ATP) at various concentrations of 0.5, 1.0, 2.5, 5.0, and 10.0 mg/L, respectively, and the 0 mg/L group was set as the control group at the same time. Scanning electron microscopy was used to observe the morphology of HUVECs. Western blotting was used to detect the expression of gasdermin D-N terminal domains (GSDMD-N) protein and immunofluorescence cell staining was used to detect the expression and distribution of GSDMD. Cell counting kit-8 (CCK-8) was used to detect the proliferative ability of HUVECs, and propidium iodide (PI) staining was used to detect the integrity of cell membrane of HUVECs. Results: Immunohistochemistry showed that GSDMD in gingival tissues of periodontitis was mainly distributed around blood vessels and its expression level was higher than that in healthy tissues. Micro-CT showed that alveolar bone resorption around the maxillary second molar significantly increased in ligation group mice compared with control subjects (t=8.88, P<0.001). Immunofluorescence staining showed significant colocalization of GSDMD with CD31 in the gingival vascular endothelial cells in mice of ligation group. The results of scanning electron microscopy showed that there were pores of different sizes, the typical morphology of pyroptosis, on HUVECs cell membranes in the inflammatory environment simulated by ATP combined with different concentrations of LPS, and 2.5 mg/L group showed the most dilated and fused pores on cell membranes, with the cells tended to lyse and die. Western blotting showed that the expression of GSDMD-N, the hallmark protein of cell pyroptosis, was significantly higher in 2.5 and 5.0 mg/L groups than that in the control group (F=3.86, P<0.01). Immunofluorescence cell staining showed that the average fluorescence intensity of GSDMD in 2.5 mg/L group elevated the most significantly in comparison with that in the control group (F=35.25, P<0.001). The CCK-8 proliferation assay showed that compared to the control group (1.00±0.02), 0.5 mg/L (0.52±0.07), 1.0 mg/L (0.57±0.10), 2.5 mg/L (0.58±0.04), 5.0 mg/L (0.55±0.04), 10.0 mg/L (0.61±0.03) groups inhibited cell proliferation (F=39.95, P<0.001). PI staining showed that the proportion of positive stained cells was highest [(56.07±3.22)%] in 2.5 mg/L group (F=88.24, P<0.001). Conclusions: Endothelial cells undergo significant pyroptosis in both in vivo and in vitro periodontal inflammatory environments, suggesting that endothelial cell pyroptosis may be an important pathogenic factor contributing to the pathogenesis of periodontitis.

Effect of graphite, graphene oxide, and multi-walled carbon nanotubes on the physicochemical characteristics and biocompatibility of chitosan/hyaluronic acid/hydroxyapatite scaffolds for tissue engineering applications

Bone tissue engineering (BTE) is a promising alternative approach to the repair of damaged bone tissue. This study aims to fabricate and characterize scaffolds composed of chitosan (CS), hyaluronic acid (HA), hydroxyapatite (HAp), and a combination of graphite (Gr), graphene oxide (GO), and multi-walled carbon nanotubes (MWCNT) for BTE applications. The Gr and MWCNT were functionalized by acid oxidation, while the GO was synthesized using the improved Hummers' method. The scaffolds were prepared by lyophilization, and the physical, chemical, and biological properties were evaluated. Scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDS), Fourier transform infrared (FTIR) spectroscopy, mechanical testing, water contact angle, degradation, and biocompatibility assays were used to characterize the scaffolds. The degradation rate was determined using the liquid displacement method. Pores of different sizes were present on the surface of and throughout the scaffold. According to the FTIR results, the scaffolds contained functional groups that promote cell differentiation and proliferation. These scaffolds have compressive strength, Young's modulus, and toughness similar to cancellous bone, with reasonable porosity and controllable degradation rates. Biocompatibility testing confirmed that the scaffolds support cell proliferation and differentiation.

Remediation of Brewery Wastewater Using Green Synthesized Nano-Particles

The brewing industry consumes a large amount of water needed for brewing, rinsing, and cooling purposes, and therefore produces huge amount of effluents. Therefore, the objective of this paper was to evaluate the use of Moringa oleiferra (MO) powder and synthesized 1.0 and 2.0 g TiO2NPs as green synthesized nano-particles for the remediation of brewery wastewater using standard methods. The raw wastewater sample characterization for pH, BOD, COD, Lead and coliform count were: 7.26, 935, 1045, 0.083 mg/L and 136 cfu/100 mL respectively. Results of the UV – Visible spectrophotometer showed the maximum wavelength of 275, 275, 278 and 282.50 nm for 5:20, 10:20, 15:20, 20:20 of MO and TiO2 ratio respectively, while the FTIR results show the presence of oxygen surface complex groups such as hydroxyl and carbonyl. The SEM reveals a porous surface area accompanied by several wide opening pores of different sizes and shapes, while EDX shows the concentration of titanium, Sulphur and silicon in percent weight; 85.79, 2.96 and 1.46 % respectively. Results of the wastewater treated with 50 g defatted M. oleiferra revealed the removal efficiency of 47, 93.2, 56.2, 18, 31.3, 97, 76.1, 81 and 71% for Turbidity, COD, EC, Nitrate, Nitrite, BOD, TS, TDS and TSS respectively. Results of wastewater treated with 1.0 g of TiO2 NPs showed the removal efficiency of 97.8, 94.64, 53.5, 34.2 and 35.1% for COD, BOD, EC, Nitrate and Nitrite respectively. That of 2.0 g of TiO2 NPs showed the removal efficiency of 67, 58, and 87% for Cu, Pb, and Ag respectively. Conclusively, M. oleiferra and varying proportions of green synthesized TiO2 NPs were effective in the remediation of the wastewater from brewery industry as it improves its physicochemical properties, but not so much for the heavy metal concentration.

A mathematical model for two solutes transport in a poroelastic material and its applications

Using well-known mathematical foundations of the elasticity theory, a mathematical model for two solutes transport in a poroelastic material (soft tissue is a typical example) is suggested. It is assumed that molecules of essentially different sizes dissolved in fluid and are transported through pores of different sizes. The stress tensor, the main force leading to the material deformation, is taken not only in the standard linear form but also with an additional nonlinear part. The model is constructed in 1D space and consists of five nonlinear equations. It is shown that the governing equations are integrable in stationary case, therefore all steady-state solutions are constructed. The obtained solutions are used in an example for healthy and tumour tissue, in particular, tissue displacements are calculated and compared for parameters taken from experimental data in cases of the linear and nonlinear stress tensors. Since the governing equations are non-integrable in non-stationary case, the Lie symmetry analysis is used in order to construct time-dependent exact solutions. Depending on parameters arising in the governing equations, several special cases with non-trivial Lie symmetries are identified. As a result, multiparameter families of exact solutions are constructed including those in terms of special functions(hypergeometric and Bessel functions). A possible application of the solutions obtained is demonstrated.

Adsorption enhances CH4 transport-driven hydrate formation in size-varied ZIF-8: Micro-mechanism for CH4 storage by adsorption-hydration hybrid technology

The adsorption-hydration hybrid technology holds significant potential for future CH4 storage applications. However, the transport of CH4/H2O and the mechanisms governing hydrate formation within metal-organic framework (MOF) systems remain unclear. In this study, the mechanism of CH4 adsorption, transport, and hydrate formation within ZIF-8 pores of different sizes was delineated utilizing the magnetic resonance imaging (MRI) technique. Primarily, CH4 undergoes physisorption within the inner cavity of ZIF-8, facilitating diffusion through the pores, which preferentially accumulate in larger pore spaces. Due to favorable interactions between CH4 and pre-absorbed water on the ZIF-8 surface, ZIF-8–01 and ZIF-8–02 preferentially facilitate substantial hydrate formation within larger pore spaces. The continuous hydrate growth depletes CH4 in the pore space, enabling two-way migration of adsorbed CH4 to support ongoing hydrate formation. This limited availability of adsorption sites within ZIF-8 induces the diffusion of surrounding CH4 into smaller pore spaces, facilitating the conversion of bound water. The size of the particles considerably influences the transport of physically adsorbed CH4 and impacts hydrate formation. Similar patterns are observed in the adsorption mass transfer coefficients of ZIF-8–01 and ZIF-8–02, which range from 0.0038 to 0.0044 and 0.0031 to 0.0124, respectively. The presence of more adsorption vacancies in the early stage leads to rapid diffusion adsorption of CH4 owing to strong adsorption effects. As adsorption within ZIF-8 pore cavities approaches saturation, increased water transport elevates internal gas-liquid two-phase resistance, slowing the kinetics of late-stage CH4 adsorption. At 6 MPa, CH4 with a larger particle size preferentially overcomes the gas-liquid energy barrier, expediting transport and promoting hydrate formation. Furthermore, the optimal particle sizes of ZIF-8 substantially influence physisorption and significantly improve the kinetics of hydrate formation.

Reaction kinetics of lithium-sulfur batteries with a polar Li-ion electrolyte: modeling of liquid phase and solid phase processes.

The present investigation fits the reaction kinetics of a lithium-sulfur (Li-S) battery with polar electrolyte employing a novel two-phase continuum multipore model. The continuum two-phase model considers processes in both the liquid electrolyte phase and the solid precipitates phase, where the diffusion coefficients of the Li+ ions in a solvent-softened solid state are determined from molecular dynamics simulations. Solubility experiments yield the saturation concentration of sulfur and lithium sulfides in the polar electrolyte employed in this study. The model describes the transport of dissolved molecular and ion species in pores of different size in solvated or desolvated form, depending on pore size. The Li-S reaction model in this study is validated for electrolyte 1 M LiPF6 in EC/DMC. It includes seven redox reactions and two cyclic non-electrochemical reactions in the cathode, and the lithium redox reaction at the anode. Electrochemical reactions are assumed to take place in the electrolyte solution or the solid state and cyclic reactions are assumed to take place in the liquid electrolyte phase only. The determination of the reaction kinetics parameters takes place via fitting the model predictions with experimental data of a cyclic voltammetry cycle with in operando UV-vis spectroscopy.

Preparation and Characterization of a Novel Lightweight Bio-Degradable Lignocellulosic Porous Molding Material

Wood is an abundant biomaterial and widely used in construction and furniture. Timber processing produces large amounts of residues and byproducts, which are of low value. In this study, we proposed a new strategy for the recycle of wood residues to prepare a wood porous molding material. A hydrated thermochemical grinding process followed by high-temperature and high-pressure refining was developed to convert wood powder into high-viscosity suspension. Lignocellulosic raw materials, including pine wood, beech wood, and bamboo, were compared with different grinding time. A porous material without the addition of synthetic adhesive was obtained with a density in the range of 0.28–0.67 g/cm3. The porous molding material was characterized based on fiber morphology, volume, and porosity and mechanical performance. Pores of different sizes were distributed in the samples randomly after curing and drying. The wood’s own bindings were released through the hydrated thermochemical grinding process. The porous sample made from bamboo with a grinding time of 6 h showed a high Young’s modulus (681.1 MPa), compactness (166.8 N/Sec), and hardness (517.6 N). Woody materials were more readily made into moldings since most of the cellulose crystal structure remained intact. The wood porous moldings are fully composed of lignocellulosic components and easy to recycle. This porous green material has great potential to be applied to insulation, ceiling, cabinet, and packaging.

A new interacting capillary bundle model on the multiphase flow in micropores of tight rocks

Surfactants are widely used in the fracturing fluid to enhance the imbibition and thus the oil recovery rate. However, current numerical models cannot capture the physics behind capillary imbibition during the wettability alteration by surfactants. Although the interacting capillary bundle (ICB) model shows potential in characterizing imbibition rates in different pores during wettability alteration, the existing ICB models neglect the influence of wettability and viscosity ratio on the imbibition behavior, making it difficult to accurately describe the oil–water imbibition behavior within the porous media. In this work, a new ICB mathematical model is established by introducing pressure balance without assuming the position of the leading front to comprehensively describe the imbibition behavior in a porous medium under different conditions, including gas–liquid spontaneous imbibition and oil–water imbibition. When the pore size distribution of a tight rock is known, this new model can predict the changes of water saturation during the displacement process in the tight rock, and also determine the imbibition rate in pores of different sizes. The water saturation profiles obtained from the new model are validated against the waterflooding simulation results from the CMG, while the imbibition rates calculated by the model are validated against the experimental observations of gas–liquid spontaneous imbibition. The good match above indicates the newly proposed model can show the water saturation profile at a macroscopic scale while capture the underlying physics of the multiphase flow in a porous medium at a microscopic scale. Simulation results obtained from this model indicate that both wettability and viscosity ratio can affect the sequence of fluid imbibition into pores of different sizes during the multiphase flow, where less-viscous wetting fluid is preferentially imbibed into larger pores while more-viscous wetting fluid tends to be imbibed into smaller pores. Furthermore, this model provides an avenue to calculate the imbibition rate in pores of different sizes during wettability alteration and capture the non-Darcy effect in micro- and nano-scale pores.

Biological fixation of customized implants for post-traumatic acetabular deformities and defects

Introduction The number of surgical interventions using additive technologies in medicine has been growing both in Russia and with every year. Due to the development of printing customized implants, the use of standard (imported) designs has decreased by an average of 7 % in the provision of high-tech medical care. However, the issue of the pore size of customized implants for management of post-traumatic defects in the acetabulum remains open.Objective To evaluate the results of the treatment of patients with post-traumatic acetabulum defects and deformities with the implementation in clinical practice of customized implants with structure and size porous surface that are optimal from the point of view of biological fixation.Material and methods Porous implants with different types of porous structure were produced by direct laser sintering using Ti-6Al-4V titanium alloy powders. Experimental work was carried out in vitro to determine the ability of living fibroblasts to penetrate the pores of different sizes. Next, the clinical part of this study was conducted in order to determine the signs of biological fixation of customized acetabular implants in a group of patients (n = 30).Results The results of this experiment performed to analyze the penetration of living fibroblasts into the porous structure of implants with different pore size demonstrated that metal structures with a pore size of 400-499 μm can be singled out from all others. Discussion Analysis of the literature data shows that there is no consensus on the structure and size of the pores of a customized implant. In our work, we investigated the ability of human living fibroblasts to penetrate into the surface structure of a customized implant, as a result of which we determined their optimal pore size of 400-499 microns. It should be noted that this study was conducted for a definite anatomical location: the acetabulum. However, it cannot be excluded that the data obtained are relevant for other anatomical locations.Conclusion Management of bone defects in the acetabulum area with customized implants featuring the surface pore size of 400-499 microns is a justified and relevant method. A prerequisite for the use of such implants is strict compliance with the indications for their use, careful preoperative planning and correct positioning.

Damage characteristics of pore and fracture structures of coal with liquid nitrogen freeze thaw

Liquid nitrogen (LN2) fracturing technology is a novel waterless fracturing technology that has significant potential for application in the development of coalbed methane. However, the changes in the microstructure after coal samples are treated with LN2 freeze thaw are poorly understood. Therefore, a combination of mercury intrusion porosimetry and micro-computed tomography (micro CT) was employed to investigate the evolution of pore and fracture structure of coal samples treated with LN2. The experimental results showed that the pore volume and average pore size of coal samples increase after LN2 freeze thaw. After 12 freeze thaw cycles, the change in pore volume of micropores and minipores of coal samples was not significant, while the pore volume of mesopores and macropores increased significantly before LN2 freeze thaw. The specific surface area of the pores in different size ranges of coal samples increases with the increase in the number of LN2 freeze thaw cycles; the structure of micropores and miniopores were damaged by thermal stress and frost heave force during LN2 freeze thaw; and the pore size gradually increases to form mesopores and macropores. Micro-CT images of coal samples after LN2 freeze thaw indicated the primary fractures of coal sample expanded and generated a large number of secondary fractures. The primary and secondary fractures are interconnected and ultimately form penetrated fracture enhancing the connectivity of fractures, enhancing the connectivity of the fracture structure. The key finding study is expected to provide a theoretical basis for LN2 fracturing.

Biological properties of macroporous cryostructurate based on extracellular matrix components

Objective: to study the biological properties of macroporous cryostructurate from multicomponent concentrated collagen-containing solution (MCCS) as a promising matrix for the formation of cell- and tissue-engineered constructs.Materials and methods. A macroporous spongy carrier was obtained by cryostructuring of collagencontaining extract, prepared by acetic acid hydrolysis of chicken connective tissue (BIOMIR Service, Russian Federation). N-(3-dimethylaminopropyl)-N’-ethylcarbodiimide (Sigma-Aldrich, USA) was used to make the cryostructurate water insoluble. The micromorphology of the sponge surface was studied using scanning electron microscopy. The cytotoxicity of the carrier was evaluated by reaction of the mouse NIH 3T3 fibroblast cell culture using automated microscope IncuCyte ZOOM (EssenBioscience, USA). Biocompatibility of the macroporous carrier was studied on cultures of human adipose tissue-derived mesenchymal stromal cells (AD-MSC), human hepatocellular carcinoma cell line HepG2 and human umbilical vein endothelial cell line EA.hy926. The metabolic activity of cells was determined using PrestoBlue™ reagents (Invitrogen™, USA). Cell population development during long-term cultivation of the cell-engineered construct (CEC) was assessed by fluorescencelifetime imaging microscopy over the entire surface of the sample using a Leica Dmi8 inverted microscope with Leica Thunder software (Leica Microsystems, Germany).Results. Optical microscopy and scanning electron microscopy (SEM) showed the presence of pores of different sizes in the resulting biopolymer material: large pores with 237 ± 32 μm diameter, medium-sized pores with 169 ± 23 μm diameter, and small-sized pores with 70 ± 20 μm diameter; large and medium-sized pores were predominant. The studied media did not exhibit cytotoxicity. Cell adhesion and proliferation on the surface of the material and their penetration into the underlying layers during long-term cultivation were observed. The highest metabolic activity of the cells was observed for human AD-MSC on day 14, which corresponds to the normal dynamics of development of a population of cells of this type. The functional activity of HepG2 cells – albumin and urea production – was shown in the liver CEC model.Conclusion. The good adhesion and active proliferation that were shown for the three cell types indicate that the resulting biopolymer carrier is biocompatible, and that the spread of the cells into the inner volume of the sponge and active population of the sponge under prolonged culturing indicates that this material can be used to create cell- and tissue-engineered constructs.

Improving the quality of soluble dietary fiber from Poria cocos peel residue following steam explosion.

Poria cocos peel residue (PCPR) still contains much soluble dietary fiber (SDF), steam explosion (SE) treatment was applied to PCPR to create a superior SDF. Steam pressure of 1.2MPa, residence period of 120s, and moisture content of 13% were the optimized parameters for SE treatment of PCPR. Under optimized circumstances, SE treatment of PCPR enhanced its SDF yield from 5.24% to 23.86%. Compared to the original SDF, the SE-treated SDF displayed improved enzyme inhibition, including the inhibition of α-amylase and pancreatic lipase, also enhanced water holding, oil holding, water swelling, nutrient adsorption including cholesterol, nitrite ions, and glucose and antioxidant abilities. Additionally, it had a decreased molecular weight, improved thermal stability, and a rough surface with many pores of different sizes. Given that SDF had been improved physiochemical and functional characteristics thanks to SE treatment, it might be the excellent functional ingredient for the food business.

Fast permeability estimation using NMR well logging data log-normal decomposition

Nuclear magnetic resonance (NMR) well logging and NMR core analysis provide a non-invasive approach to a fast reservoir rock pore structures evaluation. The NMR data is presented as a time distribution called transverse relaxation time spectrum (T2 spectrum) and, with proper adjustment, the area under the T2 distribution curve is directly related to the porosity of the reservoir rock. Based on the assumption that immovable and free fluid are present in pores of different sizes, NMR well logging and core analysis use these differences to characterize the fluids found inside the rock pores. In this way, a fixed T2 value can be selected as a cutoff. The amplitudes of the T2 spectrum that have their T2 coordinates below this fixed value are related to the fluids that are in the small pores (immovable fluids), and those that have their T2 coordinates above this value are related to the large pores (free or movable fluids). This T2 value is called T2cutoff and can be estimated in a laboratory with NMR data acquisition on water-saturated core samples. This is done by comparing the NMR acquisition data from a plug fully saturated with water with the NMR acquisition data taken from the same partially saturated plug. In this work, a new method to estimate the pore size distribution, a variable T2cutoff curve, and the Timur–Coates permeability curve of the formation along the reservoir rock is presented. The method is based on the decomposition in log-normal components of the T2 spectra of NMR well logging and on the permeability and porosity of plugs, measured in a laboratory.

Capturing size effects in effective field methods through the prism of strain gradient elasticity

The majority of studies in the open literature use homogenization models that consider microstructural parameters such as shape, orientation, distribution, and volume fraction of inhomogeneities. However, size effects, that become important when small scales are considered, are not taken into account. This study presents a novel approach by combining property contribution tensors with strain gradient elasticity to offer a formulation of effective field methods (EFM) that captures size effects in a single step and improves the accuracy of predictions about effective elastic properties. Three commonly used EFM are considered, i.e., the Non-Interaction, the Mori–Tanaka, and the Maxwell. The effectiveness of the novel approach is validated through comparison with previous formulations in the open literature that do not consider property contribution tensors. The novel approach is further tested by applying it to a simple case of a material containing pores of different sizes and comparing the results with two-step homogenization approaches and finite element models from the open literature. The comparison demonstrates the ability of the novel formulation to capture size effects and to closely follow the predictions of the FE models.

Enhanced catalytic behavior of La2O2CO3/Co3O4 composite for thermal decomposition of ammonium perchlorate

In this work, La2O2CO3, Co3O4 and La2O2CO3/Co3O4 composites were prepared by one-step solution combustion with citric acid as oxidant and lanthanum nitrate and cobalt nitrate as reductants. Morphology analysis showed many pores of different sizes on the surface of the composite. The best catalytic performance was for the La2O2CO3/Co3O4 composite. The high-temperature decomposition (HDT) of ammonium perchlorate (AP) decreased by 187.7 °C, and the activation energy decreased from 371.6 to 140.6 kJ mol−1. The combustion process of AP/hydroxyl-terminated polybutadiene solid propellant containing La2O2CO3/Co3O4 was more intense, the ignition delay time was shortened from 30 to 25 ms and the time to reach maximum combustion effect was advanced from 370 to 190 ms. Through the mechanism analysis, we believe that the adsorption of NH3 by La2O2CO3 promotes AP decomposition and also causes breakage of N–H bonds, which accelerates the oxidative decomposition of NH3. The Co3O4 has unfilled 3d orbitals, which could accelerate electron transfer during the reaction. At the same time, the interface between the two substances leaks more active sites, further accelerating electron transfer. Therefore, La2O2CO3/Co3O4 composites are expected to be widely used in solid propellants.