Porous Properties Research Articles

Experimental Study of a Bionic Porous Media Evaporative Radiator Inspired by Leaf Transpiration: Exploring Energy Change Processes

The performance of photovoltaic (PV) cells is significantly influenced by their operating temperature. While conventional active cooling methods are limited by economic feasibility, passive cooling strategies often face challenges related to insufficient heat dissipation capacity. This study presents a bio-inspired evaporative heat sink, modeled on the transpiration and water transport mechanisms of plant leaves, which leverages porous media flow and heat transfer. The device uses capillary pressure, generated through the evaporation of the cooling medium under sunlight, to maintain continuous coolant flow, thereby achieving effective cooling. An experimental setup was developed to validate the device’s performance under a heat flux density of 1200 W/m2, resulting in a maximum temperature reduction of 5 °C. This study also investigated the effects of porous medium thickness and porosity on thermal performance. The results showed that increasing the thickness of the porous medium reduces cooling efficiency due to reduced fluid flow. In contrast, the effect of porosity was temperature-dependent: at evaporation temperatures below 67 °C, a porosity of 0.4 provided better cooling, while at higher temperatures, a porosity of 0.6 was more effective. These findings confirm the feasibility of the proposed device and provide valuable insights into optimizing porous media properties to enhance the passive cooling of photovoltaic cells.

Cross-linked chitosan/pencil clay hybrid beads for the adsorption of reactive black 5

Chitosan (CH) and pencil clay (CL) were utilized to prepare stable epichlorohydrin cross-linked chitosan-clay hybrid beads (CCHB) for the adsorptive removal of anionic reactive black 5 (RB5) dye. Among various percentage weight ratios of chitosan/clay hybrid beads, 40 % CH–60 % CL was selected as the best adsorbent owing to its stability and removal efficiency. The pore properties of CCHB in terms of surface area, total pore volume, and average pore width were 40.33 m2/g, 0.088 cm3/g, and 86.06 Å, respectively. The adsorption behavior of RB5 on CCHB followed Langmuir and pseudo-second-order models. Thermodynamic parameters confirm the endothermic and spontaneous nature of RB5 adsorption and the regeneration studies reveal a negligible decrease in removal efficiency of CCHB after 5 adsorption-desorption cycles. The CCHB exhibited adsorption capacities of 169.49, 200.00, and 227.27 mg/g for RB5, respectively, at 30, 40, and 50 °C. The prepared chitosan-clay hybrid bead adsorbent can be efficiently applied for anionic wastewater treatment.

Self-Supported Porous Carbon Monoliths for Electrocatalytic Hydrogen Evolution in Alkaline Freshwater and Seawater.

Developing efficient catalysts for seawater electrolysis hydrogen evolution reaction (HER) is crucial for producing green hydrogen. Carbonized wood (CW), a porous carbon monolith, is a promising self-supporting electrocatalytic electrode owing to its environmentally friendly, sustainable, and hierarchically porous properties. However, the impact of different tree species on the hydrogen evolution performance remains unclear. In this study, various types of CWs, including carbonized poplar (PoCW), carbonized balsa (BaCW), carbonized fir (FiCW), and carbonized pine (PiCW), have been selected to investigate their electrocatalytic performance in hydrogen evolution. Among these, the PoCW exhibits superior electrocatalytic HER performance compared to the other CWs, attributed to its electrochemically active surface area, resistance, and the content of oxygen-containing functional groups. PoCW demonstrates a low overpotential of 284 mV and 356 mV at 10 mA cm-2 in alkaline freshwater and seawater, respectively. Moreover, PoCW shows long-term durability for 100 h in both alkaline freshwater and seawater. This work guides the selection of wood-based carbon monoliths and demonstrates that metal-free, CW-based self-supporting electrodes hold great potential for electrocatalytic hydrogen evolution in both freshwater and seawater.

Prediction and Optimization Design of Porous Structure Properties of Biomass-Derived Biochar Using Machine Learning Methods

Biochar produced from biomass by pyrolysis and activation is a platform porous carbon material that has been widely used in many areas. The porosity properties of biochar such as specific surface area (SSA), total pore volume (Total_PV), micropore volume (Micro_PV), mesopore volume (Meso_PV), and average pore size (Average_PS) are essential to biochar applications. Although previous machine learning (ML) models can precisely predict SSA and Total_PV, these models are unable to comprehensively predict the other porosity characteristics. More importantly, activation, which is a critical process for preparing high-porosity biochar, was generally not considered in previous studies. Here, six single-target models were established first based on pyrolysis & activation conditions for the prediction of SSA, Total_PV, Micro_PV, Meso_PV, Average_PS, and yield, obtaining test R2 of 0.89, 0.86, 0.88, 0.89, 0.76 and 0.91, respectively. Then, a multi-target model was established for simultaneous prediction with an average test R2 of 0.87. ML model interpretation indicated agent type and ratio were crucial to porosity properties. Finally, activation and direct pyrolysis biochar production optimum schemes were derived from ML model for a high porosity. Favorable experimental verification results were obtained with validation R2 of 0.98, indicating the great potential of using ML for biochar engineering.

Improved CO2 capture capacity of waste sawmill dust derived activated carbon employing novel high-pressure CO2 activation

The porosity of activated carbon is significantly influenced by both the precursor biomass and the activation parameters. Waste sawmill wood (WSW) dust, an abundantly available precursor from the furniture manufacturing, construction, carpentry, and shipbuilding industries, was collected, dried, pulverized, carbonized, and activated using steam and a novel high-pressure CO2 activation approach. Activation was performed in a tubular furnace at 800 °C with a pure CO2 flow for 90 min at 1 MPa pressure (WSW-A800-CO2-90 min-1 MPa). Another activated carbon sample was synthesized from the same precursor at atmospheric pressure using steam flow at 700 °C for 20 min (WSW-A700-Steam-20 min). XRD and FTIR analyses were conducted to compare the structural information of both samples. Additionally, the thermal characteristics of the samples were determined by measuring their specific heat capacities. N2 and CO2 adsorption experiments were performed to investigate the porous properties and CO2 capture capacities of the synthesized samples. The activated carbon synthesized in a pressurized CO2 environment produced a BET surface area of 684 m2/g, while steam activation achieved a BET surface area of 947 m2/g. Interestingly, despite the lower surface area of the CO2-activated sample, it exhibited a higher CO2 adsorption capacity (106.29 mg/g at 5 °C and 110 kPa) compared to the steam-activated carbon due to its unique pore size distribution. The experimental CO2 adsorption data were also correlated with Langmuir, Freundlich, and modified Dubinin-Astakhov (D-A) models to elucidate the CO2 capture parameters, such as isosteric heat of adsorption, activation energy, and Gibbs free energy.

Exploring high-connectivity three-dimensional covalent organic frameworks: topologies, structures, and emerging applications.

Covalent organic frameworks (COFs) represent a highly versatile class of crystalline porous materials, formed by the deliberate assembly of organic building units into ordered two-dimensional (2D) and three-dimensional (3D) structures. Their unique combination of topological precision and tunable micro- or mesoporous architectures offers unmatched flexibility in material design. By selecting specific building units, reactive sites, and functional groups, COFs can be engineered to achieve customized skeletal, porous, and interfacial properties, opening the door to materials with optimized performance for diverse applications. Among recent advances, high-connectivity 3D COFs have emerged as a particularly exciting development, with their intricate network structures enabling unprecedented levels of structural complexity, stability, and functionality. This review provides a comprehensive overview of the synthesis strategies, topological design principles, structural characterization techniques, and emerging applications of high-connectivity 3D COFs. We explore their potential across a broad range of cutting-edge applications, including gas adsorption and separation, macromolecule adsorption, dye removal, photocatalysis, electrocatalysis, lithium-sulfur batteries, and charge transport. By examining these key areas, we aim to deepen the understanding of the intricate relationship between structure and function, guiding the rational design of next-generation COF materials. The continued advancements in this field hold immense promise for revolutionizing sectors such as energy storage, catalysis, and molecular separation, making high-connectivity 3D COFs a cornerstone for future technological innovations.

Development of the design and synthesis of metal-organic frameworks (MOFs) - from large scale attempts, functional oriented modifications, to artificial intelligence (AI) predictions.

Owing to the exceptional porous properties of metal-organic frameworks (MOFs), there has recently been a surge of interest, evidenced by a plethora of research into their design, synthesis, properties, and applications. This expanding research landscape has driven significant advancements in the precise regulation of MOF design and synthesis. Initially dominated by large-scale synthesis approaches, this field has evolved towards more targeted functional modifications. Recently, the integration of computational science, particularly through artificial intelligence predictions, has ushered in a new era of innovation, enabling more precise and efficient MOF design and synthesis methodologies. The objective of this review is to provide readers with an extensive overview of the development process of MOF design and synthesis, and to present visions for future developments.

Regulating the porous properties of polyaniline enhances the electron transfer process and methane production during anaerobic wastewater treatment

Conductive materials are known to enhance methane production in anaerobic treatment process by facilitating direct interspecies electron transfer (DIET). However, the role of the porous structure of conductive materials in electron transfer remains underexplored. Polyaniline (PANI) was used as conductive materials in this study due to its easily controlled porosity, investigating how surface area and pore size affect methane production. It was demonstrated that the porosity of PANI is an important factor affecting methane production by anaerobic sludge. Methane production rate of 41.2 mL/h was achieved with the high-porosity PANI, which was ~73.2% higher than the control group. The porous PANI enhanced the electric field in the anaerobic sludge, facilitating the enrichment of electrogenic bacteria and archaea. In the anaerobic system supplemented with porous PANI, the maximum accumulation of acetic acid reached 3.72 mM. The abundance of electroactive bacteria Clostridium involved in DIET increased by 2.13-fold, while the abundance of electroactive archaea Methanosaeta and Methanobacterium, which also participate in DIET, rose by 1.55-fold. The porous structure of PANI promotes DIET and enhances aceticlastic methanogenesis.

Ordered mesoporous SiO2 as hemoperfusion adsorbents for enhanced selectivity of bilirubin removal from blood

Excessive bilirubin poses a significant risk factor in the progression of chronic liver disease. However, due to its nature as an albumin-bound toxin, bilirubin cannot be efficiently eliminated through conventional hemodialysis therapy or existing hemoperfusion adsorbents, presenting a challenge in selective removal. It is widely acknowledged that adjusting the pore properties of adsorbents can impact the adsorption efficiency of a hemoperfusion adsorbent. However, few studies have been working on improving the selectivity of bilirubin removal through precise regulation of pore size. In this paper, we aim to demonstrate that the selectivity of bilirubin removal can be achieved and enhanced by fine-tuning the pore size of ordered mesoporous materials. Ordered mesoporous SiO2 (OMS) is selected as the research object due to its highly organized and uniform porous structure, as well as its excellent biocompatibility. The results indicate that OMS nanoparticles with a pore diameter of 2.5 nm (OMS-2.5 nm) exhibit superior adsorption capacity for bilirubin in both pure and albumin-rich solutions, suggesting the potential for achieving efficient and selective bilirubin removal through pore size optimization. Furthermore, to demonstrate the feasibility of OMS nanoparticles in practical applications (i.e. their inheritability of selectivity), we engineered OMS nanoparticles into polyvinyl alcohol (PVA) microspheres, forming OMS/PVA composite microspheres. The incorporation of OMS nanoparticles significantly enhances the bilirubin adsorption capacity of PVA microspheres while simultaneously reducing their albumin adsorption. The excellent selective adsorption efficacy of OMS-2.5 nm is preserved in the composite microspheres, underscoring its potential therapeutic benefits for treating diseases with excessive bilirubin levels.

Reduction of oil absorption and acrylamide content in banana slices by infrared frying

AbstractBackgroundThe crust characteristics of fried crisps determine their oil absorption. Starch structures, as the main components of fried starchy fruits and vegetables, influence their crust formation and properties. This study investigated the reduction of oil uptake and acrylamide content in infrared‐fried (IF) banana slices by modifying starch structures at varying infrared power levels.ResultsInfrared heating improved heat transfer and surface moisture removal in fried banana slices. It facilitated crust formation in the IF samples and produced increased crust uniformity, crust ratio, and hardness. Analysis of the porous properties showed that the volume fraction of pores sized 100–250 μm was reduced in IF samples but the proportion of pores with a diameter ranging from 0.02 to 10 μm was increased. Infrared frying reduced the total oil uptake, surface oil, and structural oil content in banana slices, and each of these measures decreased as infrared power levels increased. Characterization of the starch structures suggested that the damage to the crystalline structure was increased in IF samples and more starch‐lipid complexes were generated, which would be responsible for the formation of a denser and thicker crust. The acrylamide content in the IF sample was reduced, as determined by liquid chromatography–tandem mass spectrometry (LC–MS/MS).ConclusionModifications to starch structures (crystalline structures and chemical structures) play a crucial role in oil absorption in fried starchy fruits and vegetables. Infrared frying can be used as an alternative method to produce low‐fat fruits and vegetable crisps with reduced acrylamide content. © 2024 Society of Chemical Industry.

Dynamic characteristics of soil pore structure and water-heat variations during freeze-thaw process

Freeze-thaw processes in cold regions alter soil pore structure and properties, leading to engineering geological issues. Soil pores are crucial, but research on their changes and freeze-thaw impacts is limited. This study used MRI-Cryogenic Soil Moisture Analyzer (MRI-CSMA) to explore pore structure, water, and temperature changes in saturated loess during freeze-thaw, and Scanning Electron Microscopy (SEM) to compare changes before and after. The results indicate that during the freezing process, the temperature in the frozen zone of the soil sample exhibited a staged change characterized by rapid cooling, transitional cooling, and stabilization at low temperatures, while the temperature decrease in the unfrozen zone showed no significant stages. Freeze-thaw action significantly affected the macropores and mesopores in the frozen zone, with an average increase of 15 % in macropores, a decrease of 16 % in mesopores, and minimal change in micropores (about a 1 % increase). In the unfrozen zone, there was a slight increase in micropores and mesopores (2 % and 3 %, respectively), and a 4 % decrease in macropores. Furthermore, during the freezing process, macropores in the unfrozen zone gradually decreased, while mesopores and micropores increased, leading to soil structure densification and promoting water migration towards the freezing front. This resulted in an initial increase followed by a decrease in water content near the freezing front during the early stages of freezing, confirming the view that pore structure compression drives water migration in the early stages of soil freezing. This study provides important insights for addressing engineering geological issues in cold regions under freeze-thaw conditions.

Upcycling stale bread into (meso)porous materials: Xerogels and aerogels

This work explores the upcycling of stale bread into bio-based, low-density porous materials with partial mesoporosity, produced through gelatinization and drying, using either supercritical CO2 (aerogels) or low-vacuum conditions (xerogels). Cryogels were also fabricated via freeze-drying for comparison purposes. Stale bread particles (Bread) were subjected to proteolytic gluten depletion (Gluten-Depleted Bread, GDB) or particle size reduction (Finely milled Bread, FB) to investigate the effect of protein removal or particle size on porous materials’ properties. Porous materials made from wheat starch (WS) and wheat flour (Flour) were also examined for comparison. The solvent exchange induced volume shrinkage (SE-VS), which accounted for over 87% of the total shrinkage, ranged from 62% in GDB to 78% in WS. Bread-based porous materials presented comparable specific surface area (∼40 m2/g) and water absorption capacity (∼400%) to WS materials, but outperformed in resistance to volume shrinkage, resulting in lower density. FB porous materials possessed a higher specific surface area than Bread materials, indicating the benefits of particle size reduction. Furthermore, gluten depletion resulted in GDB-aerogels with the highest specific surface area (∼80 m2/g), highlighting the benefits of gluten depletion. However, WS materials exhibited significantly greater maximum compressive stress (>2.0 MPa) and compressive modulus (>6 MPa) than stale bread-based porous materials. Importantly, the porous properties of xerogels and aerogels were similar (differences < 10%), indicating the feasibility of using low vacuum drying to produce new porous materials with partial mesoporosity (surface area 60–80 m2/g) from stale bread at a lower cost.

Advancements in renewable energy: Achieving milder reaction conditions in biodiesel synthesis from green seed canola oil with pristine ZIF-8

This study explores the enhancement of reaction conditions for biodiesel production from green seed canola oil through the methanolysis reaction using pristine ZIF-8 as a catalyst. The research focused on the effects of varying the methanol-to-oil molar ratio, temperature, and reaction time as well as their combined effects on biodiesel yield. To analyze these factors, Response Surface Methodology (RSM) paired with Central Composite Design (CCD) was employed. The quadratic model was identified as the best fit for the experimental data, evidenced by a high determination coefficient (R²) of 0.99, with all model parameters proving significant. A comprehensive characterization of the catalyst was conducted using various techniques. The surface and pore properties were examined using N2 adsorption-desorption measurements. X-ray diffractometry (XRD) was employed for structural analysis, while X-ray photoelectron spectroscopy (XPS) presented the binding information of the sample. Fourier transform infrared spectroscopy (FT-IR) provided insights into the functional groups present. Thermal gravimetric analysis (TGA) assessed the thermal stability of the catalyst. Results revealed that ZIF-8 significantly improved biodiesel production, with optimal conditions identified at a reaction temperature of 160 °C, a duration of 2.5 h, and methanol to oil (M/O) molar ratio of 26, resulting in a biodiesel yield of 85 %. This yield is close to the predicted value, demonstrating the reliability of the developed model. The kinetic analysis was performed under optimal reaction conditions. From this, the activation energy (Ea) and the pre-exponential factor (A) were obtained to be 14.5 kJ/mol and 3.4×10−7 min−1, respectively. The use of pristine ZIF-8 in biodiesel production from a low-quality and cheap oil offers a more efficient and milder reaction conditions, with potential for significant reductions in production costs and environmental impact.

Effect of layered fertilizer strategies on rapeseed (Brassica napus L.) productivity and soil macropore characteristics under mechanical direct-sowing

Layered fertilization parameters affects crop root system configuration and growth distribution, which in turn affects soil pore properties and aggregate structure. Therefore, understanding the spatial distribution of the root system and soil pore space is helpful in choosing a reasonable fertilization ratio in production practice, which ensures high and stable crop yields and at the same time improves fertilizer utilization and soil health. Albeit the impact of layered fertilization ratio at varied rates on soil pore characteristics in the soil profile at a microscale level remains limited. This study quantifies the impacts of layered fertilization ratio under on rapeseed root distribution and soil pore characteristics using the root analysis system and X-ray computed tomography (XCT). A new fertilization pattern that shallow-deep layer synchronized mechanical sowing was using, rotary tillage mixed fertilization in the shallow layer and 10 cm side-deep band fertilization in the deeper layer. It set five ratios of fertilizer amounts between shallow and deep layers as 0:4 (FD), 1:3 (FL), 2:2 (FM), 3:1 (FH), and 4:0 (F0), with non-fertilization (CK) as the control treatment. The results indicated that layered fertilization effectively improved the rape root conformation and spatial distribution, significantly increased total soil porosity and moisture content, and reduced soil bulk density and resistance (P < 0.05). Additionally, root configuration is closely related to soil pore structure and crop yield. Notably, compared with other treatments, the macroscopic porosity, equivalent pore diameter, hydraulic radius and roundness of FM treatment are significantly improved, and it effectively improves the yield and quality of rapeseed. Correlation analysis showed that the root system configuration parameters were negatively correlated with soil bulk density and resistance but positively correlated with soil moisture content, and macropore morphology parameters and rapeseed yield. Our study demonstrate that layered fertilization can improved rape growth and soil macropore porosity, but its effect depends on good tillage macropore characteristics and distribution created by reasonable fertilization ratio, which provided a theoretical basis for high-yield, efficient, green, and sustainable mechanized direct-sowing production of rapeseed.

Mechanisms of Action Underlying Conductance-Modifying Positive Allosteric Modulators of the NMDA Receptor.

N-methyl-D-aspartate receptors (NMDARs) are ionotropic glutamate receptors that mediate a slow, Ca2+-permeable component of excitatory neurotransmission. Modulation of NMDAR function has the potential for disease modification as NMDAR dysfunction has been implicated in neurodevelopment, neuropsychiatric, neurologic, and neurodegenerative disorders. We recently described the thieno[2,3-day]pyrimidin-4-one (EU1622) class of positive allosteric modulators, including several potent and efficacious analogs. Here we have used electrophysiological recordings from Xenopus oocytes, human embryonic kidney cells, and cultured cerebellar and cortical neurons to determine the mechanisms of action of a representative member of this class of modulator. EU1622-240 enhances current response to saturating agonist (doubling response amplitude at 0.2-0.5 μM), slows the deactivation time course following rapid removal of glutamate, increases open probability, enhances coagonist potency, and reduces single-channel conductance. We also show that EU1622-240 facilitates NMDAR activation when only glutamate or glycine is bound. EU1622-240-bound NMDARs channels activated by a single agonist (glutamate or glycine) open to a unique conductance level with different pore properties and Mg2+ sensitivity, in contrast to channels arising from activation of NMDARs with both coagonists bound. These data demonstrate that previously hypothesized distinct gating steps can be controlled by glutamate and glycine binding and shows that the 1622-series modulators enable glutamate- or glycine-bound NMDARs to generate open conformations with different pore properties. The properties of this class of allosteric modulators present intriguing therapeutic opportunities for the modulation of circuit function. SIGNIFICANCE STATEMENT: NMDA receptors are expressed throughout the central nervous system and are permeable to calcium. EU1622-240 increases open probability and agonist potency while reducing single-channel conductance and prolonging the deactivation time course. EU1622-240 allows NMDA receptor activation by the binding of one coagonist (glycine or glutamate), which produces channels with distinct properties. Evaluation of this modulator provides insight into gating mechanisms and may lead to the development of new therapeutic strategies.

Reconstruction of reservoir rock using attention-based convolutional recurrent neural network

The digital reconstruction of reservoir rock or porous media is important as it enables us to visualize and explore their real internal structures. The reservoir rocks (such as sandstone and carbonate) contain both spatial and temporal characteristics, which pose a big challenge in their characterization through routine core analysis or x-ray microcomputer tomography. While x-ray micro-computed tomography gives us three-dimensional images of the porous media, it is often impossible to quantify the variability of the pore, grains, structure, and orientation experimentally. Recently, machine learning has successfully demonstrated the reconstruction ability of reservoir rock images or any porous media. These reservoir rock images are crucial for the digital characterization of the reservoir. We propose a novel algorithm consisting of the convolutional neural network, an attention mechanism, and a recurrent neural network for the reconstruction of reservoir rock or porous media images. The attention-based convolutional recurrent neural network (ACRNN) can reconstruct a representative sample of reservoir rocks. The reconstructed image quality was checked by comparing them with the original Parker sandstone, Leopard sandstone, carbonate shale, Berea sandstone, and sandy medium images. We evaluated the reconstruction by measuring pore and throat properties, two-point probability function, and structural similarity index. Results show that ACRNN can reconstruct reservoir rock or porous media of different scales with approximately the same geometrical, statistical, and topological parameters of the reservoir rock images. This deep learning method is computationally efficient, fast, and reliable for synthetic image realizations. The model was trained and validated on real images, and the reconstructed images showed excellent concordance with the real images having almost the same pore and grain structures. The deep learning-based digital rock reconstruction of reservoir rock or porous media images can aid in rapid image generation to better understand reservoir rock or subsurface formation.

Statistical Comparison between Pores and Sunspots during the Time Interval 2010–2023

To reveal the physical properties of pores and sunspots varying with solar cycle, we carried out a statistical comparison among pores, transitional sunspots, and mature sunspots using Solar Dynamics Observatory/Helioseismic and Magnetic Imager from 2010 April to 2023 July. The OTSU method and region-growing algorithm were combined to detect umbrae of 11,876 sunspots covering solar cycles 24 and 25. The relationships between umbral area, continuum intensity (I), line-of-sight (LOS) magnetic field strength (B los), and line-of-sight velocity (V los) of umbrae were investigated in detail. The main conclusions are as follows. (1) The steepness between the total magnetic flux and total area of transitional sunspots appears to be flattened in each phase of the observed solar cycles, and does not have a significant variation over the solar cycle. (2) For three groups of sunspots, the umbral physical parameters’ means and their correlations show only minor variations with the solar cycle, which are in error ranges. (3) As the mean umbral LOS magnetic field strength increases, the correlation of the umbral I–B los increases. The flattening of transitional sunspots in total area–total magnetic flux scatter is related to the evolution of sunspots itself, and may not correspond to the solar cycle. The umbral physical parameters and their correlations do not exhibit a discernible regularity over the solar cycle. Our analysis results contribute to a more comprehensive understanding of the dynamic processes of sunspot magnetic fields and give a new perspective on revealing the physical features of vertical magnetic flux tubes.

The novel incorporation of lignin-based systems for the preparation of antimicrobial cement composites

This paper, for the first time, presents a potential application of titanium(IV) oxide and silicon(IV) oxide combined with lignin through a solvent-free mechanical process as admixtures for cement composites. The designed TiO2–SiO2 (1:1 wt./wt.) hybrid materials mixed with lignin were extensively characterized using Fourier transform infrared spectroscopy (FTIR), electrokinetic potential analysis, thermal analysis (TGA/DTG), and porous structure properties. In addition, particle size distributions and scanning electron microscopy (SEM) were conducted to evaluate morphological and microstructural properties. In the next step, the effect of the TiO2–SiO2/lignin hybrid admixture on the workability, hydration process, microstructure, porosity, mechanical, and antimicrobial properties of the cement composites was evaluated. It was observed that appropriately designed hybrid systems based on lignin contributed to better workability, with an improvement of 25 mm, and reduced porosity of cement composites, decreasing from 14.4 % to 13.3 % in the most favorable sample. Additionally, a higher microstructure density was observed, and with increasing amounts of hybrid material admixture, the mechanical parameters also improved. In addition, the TiO2–SiO2/lignin hybrid systems had significant potential due to their high microbial purity, suggesting their effectiveness in minimizing microbial accumulation on surfaces. The final stage of analysis involved employing response surface methodology (RSM) to ascertain the optimum composition of cement composites. The results obtained indicate that the TiO2–SiO2/lignin admixtures are a promising approach for the valorization of lignin waste flows in the design of cement composites.

3D morphometry of endothelial cells angiogenesis in an extracellular matrix composite hydrogel

Human umbilical vein endothelial cells (HUVECs) play a fundamental role in angiogenesis. Herein, we introduce digital holographic microscopy (DHM) for the 3D quantitative morphological analysis of HUVECs in extracellular matrix (ECM)-based biomaterials as an angiogenesis model. The combination of volumetric information from DHM and the physicochemical and cytobiocompatibility data provided by fluorescence microscopy and cytology offers a comprehensive understanding of the angiogenesis-related parameters of HUVECs within the ECM. DHM enables label-free, non-contact, and non-invasive 3D monitoring of living samples in real time, in a quantitative manner. In this study, the human amniotic membrane (HAM) is decellularized, pulverized, and combined with sodium alginate hydrogel to provide an in vitro substrate for modeling HUVEC angiogenesis. Our results demonstrate that modifying alginate hydrogel with HAM enhances its biofunctionality due to the presence of ECM components. Moreover, the DHM results reveal an increase in its porous properties, which, in turn, aids in interpreting the tubulation results.

A new semi-analytical approach for nonlinear dynamic responses of functionally graded porous graphene platelet-reinforced circular plates and spherical shells

This paper presents the semi-analytical approach for nonlinear dynamic responses of porous graphene platelet-reinforced circular plates (CiPs) and spherical shells (SpSs) resting on the Pasternak foundation in thermal environment. The graphene platelets (GPLs) are distributed in the functionally graded (FG) distribution patterns and uniform distribution pattern through the CiP and SpS thickness direction. The governing equations of the GPL-reinforced structures subjected to time-dependent external pressure respected to the harmonic and linear functions of time are established based on the geometrically nonlinear higher-order shear deformation theory. A simple and effective semi-analytical solution for the considered problem is established using the Euler-Lagrange equations, and the damping viscosity of the foundation can be counted using the Rayleigh dispassion function. The Runge-Kutta method is employed to determine the dynamic responses of the GPL-reinforced structures, while the fundamental frequencies of free and linear vibration, and frequency-amplitude curves are obtained in explicit form. The numerical results obtained reveal that the GPL and porous distributions, geometrical and material properties can significantly affect the frequency-amplitude curves, and dynamic responses of harmonically loaded and linearly loaded structures, specially, the dynamic buckling phenomenon is clearly observable with the SpSs but not with the CiPs.