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This research established a systematic method to generate various pore-size distributions (PSDs) and studied the effect of PSDs on the shock compaction response of granular materials using two-dimensional mesoscale simulations under identical porosity. Simulations utilized various PSDs for three particle shapes (circle, ellipse, and square). Contacting particle configurations using three PSDs, characterized by spatially uniform distributed pores to heterogeneous distributed pores, and non-contacting particle configurations under a single case of PSD were tested. The PSD of generated particle sets was characterized using coordination number, mean diameter, and bimodality coefficient as statistical metrics. Mesoscale simulations showed that regardless of the conditions of pore distributions, shock compaction of granular materials consistently demonstrates a precursor, shock compaction front, and end. However, the shock compaction velocity of contacting particles was dependent on the PSDs despite the constant initial porosity. The compaction velocity was faster in particle configurations with relatively uniform pore distributions than in heterogeneous pore distributions, which our study demonstrated can be attributed to particle rearrangement during compaction. Circular-shaped particles had high sensitivity in shock compaction response to the various PSDs. Furthermore, a contacting particle configuration tended to propagate the shock compaction wave relatively faster than particles that were in a non-contact configuration. This study established the relative importance of considering PSD as a metric over the coordination number in studies of the shock compaction response of granular materials. Further, insights are provided on the evolving shock substructure to characterize the shock compaction response of granular materials. [ABSTRACT FROM AUTHOR]

Second Harmonic Scattering (SHS) is a suitable technique to investigate the orientational correlations between molecules. This article explores the organization of different dye molecules adsorbed within the hydrophobic porosity of a hybrid organic–inorganic nanotube. Experimental polarization resolved SHS measurements highlight different orientational orders ranking from highly ordered and rigid organizations to disordered assemblies. Microscopic models of assemblies inside the pores are presented and discussed in the context of orientational correlation between the dye molecules. This work shows that the degree of order in the nanotube cavity follows the molecule's affinity within the porosity. [ABSTRACT FROM AUTHOR]

The prevention of drying-induced cracking is crucial in maintaining the mechanical integrity and functionality of colloidal deposits and coatings. Despite exploring various approaches, controlling drying-induced cracking remains a subject of great scientific interest and practical importance. By introducing chain-like particles composed of the same material and with comparable size into commonly used colloidal suspensions of spherical silica nanoparticles, we can significantly reduce the cracks formed in dried particle deposits and achieve a fivefold increase in the critical cracking thickness of colloidal silica coatings. The mechanism underlying the crack suppression is attributed to the increased porosity and pore sizes in dried particle deposits containing chain-like particle, which essentially leads to reduction in internal stresses developed during the drying process. Meanwhile, the nanoindentation measurements reveal that colloidal deposits with chain-like particles exhibit a smaller reduction in hardness compared to those reported using other cracking suppression approaches. This work demonstrates a promising technique for preparing colloidal coatings with enhanced crack resistance while maintaining desirable mechanical properties. [ABSTRACT FROM AUTHOR]

The preparation of rigid polyurethane foam with uniform pore size is extremely challenging. In this work, double-effect baking powder was used as foaming agent, and rigid polyurethane foam with regular morphology was successfully prepared through semi-prepolymerization. The rigid polyurethane foam apertures with regular morphology were controlled by the secondary release of C[O.sub.2] when the content of baking powder is 0.30 part. Combined with theoretical calculation and experimental test, it is found that the particle size distribution, wall thickness, and hole shape are uniform, regular, thin, polygonal, and few broken holes. The compression strength, contact angle, and surface energy of the rigid polyurethane foam are 33.36 kPa, 109.6[degrees], and 21.8 mJ/[m.sup.2] after adding 0.20 part of double-effect baking powder, respectively. By adjusting the amount of double-acting baking powder, the porosity, mechanical properties and foam rate of the polyurethane foams could be significantly improved. Due to the molecular solvation effect, rigid polyurethane foams will deform in the water and oil due phase, but it can remain stable for a long time at room temperature without solvent. It provides a new method for the preparation of rigid polyurethane foam, which is expected to be widely used in transportation and other fields. Highlights * Baking powder was firstly used as a foaming modifier for rigid polyurethane. * Baking powder releases C[O.sub.2] twice to ensure uniform structure of polyurethane cell. * Rigid polyurethane foam has long-term stability and regular, uniform cell holes. * The porosity and mechanical properties of foams could be significantly improved. * Foaming mechanism of rigid polyurethane using baking powder was firstly revealed. KEYWORDS blowing agent, foam, mechanical properties, microstructure, polyurethane, 1 | INTRODUCTION With the rapid development of the transportation and logistics industry, there is an increasing demand for high-performance materials, particularly in enhancing fuel efficiency, safety, and passenger comfort. [...]

Most of the available data on diffusion in natural clayey rocks consider tracer diffusion in the absence of a salinity gradient despite the fact that such gradients are frequently found in natural and engineered subsurface environments. To assess the role of such gradients on the diffusion properties of clayey materials, through-diffusion experiments were carried out in the presence and absence of a salinity gradient using salt-diffusion and radioisotope tracer techniques. The experiments were carried out with vermiculite samples that contained equal proportions of interparticle and interlayer porosities so as to assess also the role played by the two types of porosities on the diffusion of water and ions. Data were interpreted using both a classical Fickian diffusion model and with a reactive transport code, CrunchClay that can handle multi-porosity diffusion processes in the presence of charged surfaces. By combining experimental and simulated data, we demonstrated that (i) the flux of water diffusing through vermiculite interlayer porosity was minor compared to that diffusing through the interparticle porosity, and (ii) a model considering at least three types of porous volumes (interlayer, interparticle diffuse layer, and bulk interparticle) was necessary to reproduce consistently the variations of neutral and charged species diffusion as a function of salinity gradient conditions.

We investigated the relationship between porosity and flexoelectricity for aluminum (Al)/polyvinylidene fluoride (PVDF) composites. Neat PVDF, composites of micron aluminum (μAl)/PVDF, and composites of nano aluminum (nAl)/PVDF were 3D printed, and the flexoelectric response was measured using a cantilever beam test setup. Voids (up to 72.4 mm3) were incorporated into the samples by decreasing the infill percent of the 3D printed material. We found that increasing the porosity via millimeter scale voids incorporated into the infill pattern decreased the average effective flexoelectric coefficient relative to the near full-density (100% infill) control samples. This contrasts with other studies that have shown increasing micron scale porosity increases the flexoelectric coefficient. In addition, we measured higher flexoelectric responses for nAl/PVDF than μAl/PVDF as well as for samples printed by the Hyrel 3D SR printer as opposed to the Ender 3 V2 printer. These results indicate that charge generation due to flexoelectricity can be altered by changing parameters such as porosity, particle size of inclusions, or manufacturing method. Smaller voids and fine particles can induce larger strain gradients than larger inhomogeneities, leading to increased flexoelectric coefficients. A competing effect is that more porosity leads to less materials, which can decrease the flexoelectric coefficient. [ABSTRACT FROM AUTHOR]

Reactive burn models for heterogeneous energetic materials (EMs) must account for chemistry as well as microstructure to predict shock-to-detonation transition (SDT). Upon shock loading, the collapse of individual voids leads to ignition of hotspots, which then grow and interact to consume the surrounding material. The sub-grid dynamics of shock-void interactions and hotspot development are transmitted to macro-scale SDT calculations in the form of a global reactive "burn model." This paper presents a physically evocative model, called meso-informed sub-grid source terms for energy localization (MISSEL), to close the macro-scale governing equations for calculating SDT. The model parameters are explicitly related to four measurable physical quantities: two depending on the microstructure (the porosity ϕ and average pore size D ¯ v o i d ), one depending on shock–microstructure interaction (the fraction of critical voids ξ c r ), and the other depending on the chemistry (the burn front velocity V h s ). These quantities are individually quantifiable using a small number of rather inexpensive meso-scale simulations. As constructed, the model overcomes the following problems that hinder the development of meso-informed burn models: (1) the opacity of more sophisticated surrogate/machine-learning approaches for bridging meso- and macro-scales, (2) the rather large number of high-resolution mesoscale simulations necessary to train machine-learning algorithms, and (3) the need for calibration of many free parameters that appear in phenomenological burn models. The model is tested against experimental data on James curves for a specific class of pressed 1,3,5,7-tetranitro-1,3,5,7-tetrazoctane materials. The simple, evocative, and fast-to-construct MISSEL model suggests a route to develop frameworks for physics-informed, simulation-derived meso-informed burn models. [ABSTRACT FROM AUTHOR]

Gas–liquid two-phase stratified flow exists in many industrial processes. Although the flow pattern is simple, the interfacial shear prediction of stratified flow is still the focus of the study. The calculation of the shear stress at the gas–liquid interface is closely related to the measurement of the void fraction and pressure drop of the stratified flow. In this study, a new method for the calculation of interfacial shear stress of gas–liquid two-phase stratified flow is proposed. Differential pressure measurement and planar laser-induced fluorescence technology are combined to obtain important parameters for stratified flow under low-speed flow conditions (Ql = 0.10–0.25 m3/h, Qg = 0.35–1.00 m3/h). The interfacial shear stress is successfully calculated using macroparameters. The uncertainty associated with the calculated parameters using the proposed method is 2.67%, and this study verifies the accuracy of the linear relationship. The method provides a new way to obtain the interfacial shear stress of gas–liquid stratified flow. [ABSTRACT FROM AUTHOR]

Utilizing molecular dynamics simulation, this study aims to explore the phase transformation behavior of porous nanocrystalline (NC) NiTi shape memory alloys (SMAs) when subjected to cyclic deformation. The influences of porosity and cyclic deformation on the phase transformation of NC NiTi SMAs are examined and discussed. The simulation results show that the increase in the porosity and number of cycles leads to a decrease in both the critical phase transformation stress and peak stress whereas an increase in the residual martensite, phase boundary, and interstitial atoms; the related results can be supported by previous experiments. After cyclic deformation, the reduction in the potential energy for the entire system during the tensile phase occurs at an earlier stage, indicating that the martensitic transformation occurs earlier as the number of cycles increases. Notably, the dissipated energy demonstrates a decrease with an increasing number of cycles, and the potential energy during the austenite elastic unloading stage undergoes a transition from a decreasing to an increasing trend due to the presence of residual martensite increasing with the number of cycles. [ABSTRACT FROM AUTHOR]

The behavior of energetic materials is significantly influenced by the spatial distributions of microstructure heterogeneities and voids. We pursue the concept of Functionally Graded Energetic Materials whose microstructure features (e.g., grain size, grain volume fraction, void size, and void volume fraction) change spatially such that they may allow the behavior of the materials to be tailored. We explore using gradients in the density of voids to alter the detonation behavior of a polymer-bonded explosive (PBX) echoing PBX9501 with HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) grains and Estane binder. Five cases, two graded void distributions from 1% to 10% and 10% to 1% by volume along the length of the sample, and three uniform distributions matching the lowest (1%), average (5.5%), and highest (10%) void densities are considered. An Arrhenius reaction burn model is used to account for the chemical kinetics of HMX. Different detonation behaviors are obtained from the same graded sample when impact loading is from 1% void end and from the 10% void end as well as from the uniform cases. The SDT (shock to detonation transition) behaviors are analyzed in terms of the run distance, the time duration and shock velocity changes over the SDT process. The computational results are presented in the context of available experimental data for PBX9501 with which agreement is obtained through a parametric study. Overall, it is shown that gradients in microstructures of PBX can lead to SDT behaviors different or not obtainable from microstructures without gradients, thereby offering a mechanism for designing and tailoring new materials. [ABSTRACT FROM AUTHOR]

In this study, analytical models for space charge limited current (SCLC) transport in a porous (or disordered) trap-limited dielectric cylindrical configuration are developed. The method used in this paper is first verified by reproducing the well-known analytical results for planar cases developed decades ago based on the traditional approach. By considering the porous solid as a fractional object characterized by a parameter α ≤ 1 , we formulate its fractional capacitance and determine the SCLC transport by using the transit time approach. At α = 1 , it will recover the well-known Mott–Gurney law and Mark–Helfrich law for trap-free and trap-limited cases, respectively. For cylindrical geometry, our findings show an analytical form that is not available from the traditional methods. We anticipate that the proposed analytical model will serve as a useful tool for characterizing the current–voltage measurements in SCLC transport in dielectric breakdown and organic electronics, where spatial porosity of the materials is inevitable. The introduced fractional parameter α extracted from such characterization can facilitate the quantitative determination of the relationship between spatial porosity and charge mobility. [ABSTRACT FROM AUTHOR]

Our study examines 'Finstagramming' as a resistance strategy from influencers trying to circumvent the prescriptive nature and restrictive algorithm of Instagram. Without ever leaving the platform, Finstagram acts as an emancipatory outlet that enables influencers to share more intimate, less-conforming and unpolished content without jeopardising the highly curated, monetizable person-brand of their main account. Through a dual-method qualitative approach of netnography and in-depth interviews, we unravel this paradox of embedded escapism, where influencers toggle between main and Finsta accounts in their pursuit of authenticity. Our findings reveal the porosity of these multiple digital personae and differentiated digital work taking place on the platform. We argue that Finstagram affords a momentary escape from the digital attention economy whilst remaining tethered to socially mediated authenticity markers. [ABSTRACT FROM AUTHOR]

Sulfonated hierarchical H-ZSM-5 monoliths were synthesized via ice-templating as solid acid catalysts for biodiesel production. Characterization confirmed successful –SO3 group grafting, increasing acid density. The catalysts achieved over 90% conversion of oleic acid in esterification, with easy recovery and reuse, and the relationship between porosity and acid density was explored. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) are considered as potential solid-state electrolyte (SSE) materials due to their structural diversity and porosity. Adding lithium ions into the anionic frameworks of MOFs and then realizing single-ion transport is an efficient way to enhance the performance of ionic conductivity of SSE materials. Herein, an ionotropic MOF (Li+[Cu-BTC]−) with lithium ions in the pores of the lattice was synthesized through an ion exchange strategy, which exhibits outstanding lithium ionic conducting properties over a wide temperature range (ionic conductivity: 0.11–2.96 × 10−3 S cm−1 in the temperature range of −40 to 100 °C). The strategy of injecting Li+ within anionic metal–organic frameworks provides a new opportunity for exploring advanced SSEs. [ABSTRACT FROM AUTHOR]

Fused deposition modeling (FDM), an economical additive manufacturing (AM) technique, is widely used for extruding thermoplastic filaments. Acrylonitrile butadiene styrene (ABS) is a widely used polymer for FDM technique due to its inexpensive cost, strong impact strength, great durability, and intriguing uses. ABS materials are used for interior parts of automotive applications, drug-delivery systems, tracheal tubes, valves for ventilators, and medical masks. Nonetheless, shrinkage and warping are the primary weaknesses of ABS during the FDM process, affecting the dimensional stability of printed parts. In this context, a patent-pending radiant heating system has been developed to improve the overall performance of printed parts. This study aimed to evaluate the effect of in situ thermal treatment on the interlayer adhesion and mechanical properties of printed ABS parts. The thermal treatment was carried out on a radiant heating system at 240 °C and a printing speed of 35 mm·s−1. The physical and mechanical properties of ABS parts printed with and without radiant heating were then characterized. Various techniques, including tensile tests, X-ray microtomography (µ-CT), optical profilometry (OP), atomic force microscopy (AFM), and dynamic mechanical analysis (DMA), were conducted to investigate mechanical, microstructural, and topological properties of printed ABS parts. The results show that treated samples exhibit better interlayer adhesion than untreated ones. In addition, the treated samples had a lower porosity (1.6%) than the untreated samples (3%). Furthermore, the tensile strength, elastic modulus, and elongation at break of treated samples increased by 62%, 6%, and 110%, respectively, compared to untreated ones. [ABSTRACT FROM AUTHOR]

Polymer-based composites, due to their versatility and tunable properties, have become essential in sorption, energy storage, and sensing applications. This review explores the fundamental chemistry underlying phase transitions within polymer matrices during composites formation, examining how anisotropic and isotropic fillers influence the mechanical, thermal, and functional properties of polymer-based composites. The role of phase transitions is emphasized as a key factor shaping the composite properties, while porosity is highlighted as a crucial attribute impacting sorption processes (absorption and adsorption) which enhances the utility of these materials in diverse modern applications. The transformations within polymer matrices during composites development and their resultant applications in sorption, sensing, and energy storage are investigated. It is examined how filler types and morphologies affect the porosity and functional performance of polymer-based composites. Future challenges and strategies for advancing the performance and sustainability of these materials are also outlined, offering insights that support ongoing research and development in advanced polymer-based composites. The review provides an analysis of current advancements and also offers guidance for future research, making it valuable for both emerging and established researchers in the field. [ABSTRACT FROM AUTHOR]

The unique structure of [2.2]paracyclophane (PCP) with its rigidity, stability, and planar chirality has gained significant attention in polymer and material research. In this work, the incorporation of amino‐functionalized PCPs within polymers of intrinsic microporosity (PIMs) is reported for the first time. Three different PCP‐PIMs were prepared via a Tröger's base formation mechanism, and their structures characterized via solid‐state NMR, MALDI‐TOF, and SEM. Their porosity was evaluated using gas adsorption (N2 and CO2) based on theoretical calculations such as Brunauer–Emmett–Teller (BET), NLDFT pore size distribution (PSD) and ideal IAST CO2/N2 selectivity (15/85), a crucial separation when considering the capture of CO2 from flue gas. The surface areas were found to be between 200–230 m2 g−1 while the selectivity for CO2/N2 ranged from 46 to 70. [ABSTRACT FROM AUTHOR]

This study investigates the synthesis of zinc-based metal–organic frameworks (MOFs) using tetrahydrofuran (THF) as a solvent, focusing on forming distinct phases as models for potential battery applications. Contrary to expectations, the synthesis produced three unique phases: alpha, beta, and Zn-MOF-74a, instead of the anticipated Zn-MOF-74 structure. Comprehensive structural analysis using X-ray diffraction, infrared spectroscopy, and thermogravimetric analysis (TGA) revealed distinct crystallographic features for each phase, particularly the novel Zn-MOF-74a phase, which exhibits a heart-shaped pore structure and differs from the classic hexagonal MOF-74. The study also includes the first structural determination of the dry H4DOBDC precursor, providing crucial insights for future research. The results demonstrate the significant impact of solvent choice, temperature, and pH on MOF phase formation and offer potential applications in energy storage and catalysis, especially for larger molecules. Further investigation is required to fully understand the electrochemical properties and phase stability of the newly identified Zn-MOF-74a and beta phases. [ABSTRACT FROM AUTHOR]

There exists a trade-off between high optical transmittance and low thermal conductivity of silica aerogels, which is medicated by adjusting the pore structures using surface modification in this work. A straightforward ambient-dried method for hydrophobic silica aerogels is proposed to avoid the costly, intricated equipment and non-scalable supercritical or freeze-drying methods. A series of aerogels were prepared by increasing the proportion of modifier, with thermal conductivity of aerogels decreasing from 0.170 to 0.0172 W m−1 K−1, and density from 0.465 to 0.173 kg m−3. It was also found that the pore size of silica aerogel does not always increase with increasing modifier. In addition, molecular dynamics simulation is combined to illustrate the effects of surface modification, and an atomic model was established aligned with experimental specific surface area to visualize the subpores. The predicted solid thermal conductivity agrees well with experimental results. The optimal heat-insulating hydrophobic silica aerogel is obtained with thermal conductivity of 0.0288 W m−1 K−1 and transparency of 78.4% at wavelength of 900 nm and thickness of 10 mm. The present work can inspire further nanostructure design of silica aerogels and may pave the way for the development of high transparent silica aerogels with low thermal conductivity. [ABSTRACT FROM AUTHOR]

In order to extend the photo-shielding range of ceria from the ultraviolet (UV) region (≤400 nm) to the high-energy short-wave blue light (BL) region (400–450 nm), three groups of ceria-based materials, including ceria nanoparticles (nano-CeO 2), cerium-oxygen-sulfur (Ce-O-S) composites and samarium-cerium-oxygen-sulfur (Sm-Ce-O-S) composites, were prepared from the perspectives of improving the preparation method, non-metal doping and metal/non-metal co-doping. Although the three groups of as-prepared samples have similar phase composition, morphology and pore structure, the Sm-Ce-O-S composites show remarkable double shielding performance for UV light and short-wave BL. Compared with nano-CeO 2 and Ce-O-S composites, Sm-Ce-O-S composites that retains the characteristics of n-type semiconductor exhibits a greater degree of lattice distortion, higher concentrations of Ce3+ (41.17 %) and oxygen vacancy (77.29 %), and narrower band gap (2.71 eV). Through the comparison of the three groups of samples, the order of modification degree from high to low is as follows: metal/non-metal co-doping > non-metal doping > improving the preparation method. This paper provides experimental and theoretical support for breaking through the bottleneck of ceria in the fields of UV shielding agents and catalysts. [ABSTRACT FROM AUTHOR]

The efflorescence problem is always an intractable problem for geopolymer. Silica fume (SF), nano-silica (NS), 5A zeolite (ZL) and nano-silica treated with silane (NST), were used to mitigate the efflorescence of fly ash (FA) - granulated blast furnace slag (GBFS) - steel slag (SS) based geopolymer. The effect of their dosages on the efflorescence was evaluated through accelerated efflorescing, leaching and unconfined compressive strength (UCS) tests. The inhibition mechanisms were explored by XRD, SEM, FTIR and MIP characterization. It revealed that SF and NS presented the most effective mitigating effect on efflorescence, with 9 % of SF and 2 % of NS totally inhibiting efflorescence and improving the compressive strength, and ZL and NST also alleviated the efflorescence at appropriate contents. Optimizing pore network and stabilizing free alkali were found to be the most important aspects for inhibiting efflorescence. The SF and NS worked efficiently in both two ways, which contained a large amount of dissolvable silicate that reacted with the excessive alkali to form C(N)-A-S-H and C-S-H gels. This filled and reduced the pores from 26 nm to less than 10 nm, and stabilized alkali with reduce the free w (Na+) by more than 50.45 %. On the other hand, ZL can solidify free alkali through the ion exchange property and fill pores due to its microaggregate nature, and NST reduced the efflorescence through blocking free alkali migration paths by hydrophobicity of the pores. These findings would guide the selection of appropriate methods to solve the efflorescence problem of geopolymers. • Reactive silicates in SF and NS can consume free alkalis to improve efflorescence resistance. • The NS inhibited free alkalis migration through optimized pore structure. • The ZL and NST mitigated efflorescence by reducing alkali leaching. [ABSTRACT FROM AUTHOR]

Modulating the emissivity of yttria-stabilized zirconia (YSZ) ceramics in the 3–5 μm range through doping and structural adjustments is crucial for their application as high-temperature low-emissivity materials. This study examined YSZ composite ceramics with various levels of lanthanum fluoride (LaF 3) doping, sintered using a high-temperature solid-phase reaction method, to compare their infrared emissivity within the 3–5 μm range. A systematic investigation focused on the effects of the crystal structure and microporous structure evolution on the infrared emissivity of YSZ/LaF 3 composite ceramics. The results revealed that increasing the LaF 3 doping led to lattice expansion and an increase in oxygen vacancies within the YSZ. When the doping limit of La3+ ions is exceeded, La 2 Zr 2 O 7 is formed. At high doping levels, the formation of volatile ZrF 4 was identified as the primary cause of increased porosity of the composite ceramics. Consequently, the emissivity of the composite ceramics in the 3–5 μm range is minimized at a doping level of 3 mol%. For small amounts of doping, this represents the optimal balance between the lattice expansion and oxygen vacancies. However, at higher doping levels, the increased porosity becomes the dominant factor, reducing the emissivity of the composite ceramics. [ABSTRACT FROM AUTHOR]

The Consteel electric arc furnace (EAF) has gained rapid development in the field of EAF steelmaking due to its advantageous features including short tap‐to‐tap time, low production energy consumption, and waste heat recovery. However, the low heat transfer efficiency from gas to scrap has remained a persistent technical challenge in Consteel EAF. This research establishes a scrap preheating model for the Consteel EAF to comprehensively investigate the heat transfer efficiency from gas to scrap. The calculation results demonstrate that the heat transfer efficiency from gas to scrap can be effectively enhanced by increasing the initial gas velocity and scrap porosity. Specifically, raising the initial gas velocity from 0.9 to 1.5 m s−1 improves convective and radiative heat exchange, leading to increased heat transfer efficiency from gas to scrap at the same positions within the scrap layer. Moreover, increasing the scrap porosity from 0.92 to 0.98 significantly enhances the heat transfer efficiency through augmented radiation heat exchange. Notably, the improvement in heat transfer efficiency resulting from increased porosity is considerably greater than that achieved through increased gas velocity. The findings of this study hold significant practical implications for the actual field production operations in the horizontal continuous feeding system of EAF. [ABSTRACT FROM AUTHOR]

Knowing the structure of the crust is critical to understanding a planet's geologic evolution. Crustal thickness inversions rely on bulk density estimates, which are primarily affected by porosity. Due to the absence of high‐resolution gravity data, Mercury's crustal porosity has remained unknown. Here, we use a model that was calibrated to the Moon to relate Mercury's impact crater population and long‐wavelength crustal porosity in the cratered terrains. Therein, porosity is created by large impacts and then decreased as the surface ages due to pore compaction by smaller impacts and overburden pressure. Our models fit independent gravity‐derived porosity estimates in the northern regions, where data is well resolved. Porosity in the cratered terrains is found to be 9%–18% with an average and standard deviation of 13% ± $\pm $ 2%, indicating lunar‐like crustal bulk densities of 2,565 ± $\pm $ 70 kg m−3 ${\mathrm{m}}^{-3}$ from which updated crustal thickness maps are constructed. Plain Language Summary: The crust of a planet is a thermal barrier, which controls how fast heat escapes to space. Depending on its thickness, the crust can strongly insulate the planet's interior preventing efficient cooling. Therefore, knowing the structure of the crust is critical to unraveling the geologic history of planetary bodies. Crustal thickness is typically inverted from gravity and topography data. One critical parameter for these inversions is the bulk density of the crust, which is primarily driven by porosity variations. While high‐resolution gravity field mapping allowed constraining the bulk density and porosity of the lunar crust, crustal porosity on other planetary bodies has remained unknown. In this work, we use a model that was calibrated to the Moon to relate Mercury's impact crater population and long‐wavelength crustal porosity in the cratered terrains. We show that crustal porosity in the cratered terrains ranges from 9% to 18% with an average and standard deviation of 13% ± $\pm $ 2%, indicating lunar‐like low bulk densities of 2,565 ± $\pm $ 70 kg m−3 ${\mathrm{m}}^{-3}$. Key Points: Mercury's crustal porosity estimated from the crater population, assuming porosity formed by large impacts and decreased with surface agingCrustal porosity in the cratered terrains ranges from 9% to 18% with an average and standard deviation of 13% ± 2%The low bulk density of Mercury's crust in the cratered terrain, 2,565 ± 70 kg m−3, is similar to that of the lunar highlands [ABSTRACT FROM AUTHOR]

Highlights This study investigates the relationship between microstructure and mechanical properties of carbon fiber reinforced epoxy composites, specifically in the context of lightweight hydrogen storage pressure vessels manufactured by the filament winding process. The filament winding technique often introduces variability in fiber orientation and porosity which can lead to inconsistencies in mechanical properties. By investigating the influence of dynamic loading over a range of strain rates, from quasi‐static to 100 s−1, this research aims to understand the effects of different fiber orientations (±15° and ±30°) and multilayer structures on the performance of these composites. Using a custom‐designed Interrupted Dynamic Tensile Test (IDTT) apparatus, we investigated how damage mechanisms evolve during rapid tensile deformation. The results showed that porosity has a significant impact on mechanical performance, particularly at high strain rates, where cracks initiate at pores and propagate via fiber/matrix decohesion and fiber breakage. These microstructural defects contribute to mesoscopic failure mechanisms such as transverse cracking and micro‐delamination between composite layers. The mechanical properties were found to be strain rate sensitive, with visco‐damage phenomena playing a critical role in determining the damage evolution under dynamic loading. These findings provide important insights into the design and optimization of hydrogen storage vessels, highlighting the importance of controlling porosity and understanding the response of the composite to varying strain rates for improved durability and performance. Comprehensive analysis of dynamic loading. Influence of fiber orientation and porosity on mechanical integrity. Visco‐damage and failure mechanisms under high strain rates. [ABSTRACT FROM AUTHOR]

The Rotokawa geothermal field is in the Taupō Volcanic Zone, New Zealand. It hosts two geothermal power plants, Rotokawa and Ngā Awa Pūrua, which together have a capacity over 170 MWe. The permeability of the rock mass comprising a geothermal field controls the volume of hot fluids that can be extracted for energy production. In this research we produce a stress model to estimate in-situ rock matrix permeability for a unique set of intact rock samples obtained from depths up to 2600 m in the Rotokawa geothermal field. We show that permeability generally decreases with sample depth, both intrinsically and in response to increasing confining pressure. We explore this confining pressure effect on other petrophysical and mechanical measurements, and highlight how rock texture and composition affect how the rocks respond to confining pressure. For example, we compare two altered andesite samples: a breccia with microfractures and infilled pores that tends to experience less compaction and porosity decrease than a lava with rounded, unfilled pores. We suggest that, when developing depth-models, measurements should be conducted at relevant in-situ conditions, if possible. Finally, we explore relationships between different physical parameters and provide estimating functions for those with the clearest correlations. [ABSTRACT FROM AUTHOR]

Strong gravitational lens system catalogues are typically used to constrain a combination of cosmological and empirical power-law lens mass model parameters, often introducing additional empirical parameters and constraints from high resolution imagery. We investigate these lens models using Bayesian methods through a novel alternative that treats spatial curvature via the non-FLRW timescape cosmology. We apply Markov Chain Monte Carlo methods using the catalogue of 161 lens systems of Chen et al. in order to constrain both lens and cosmological parameters for: (i) the standard |$\Lambda$| CDM model with zero spatial curvature; and (ii) the timescape model. We then generate large mock data sets to further investigate the choice of cosmology on fitting simple power-law lens models. In agreement with previous results, we find that in combination with single isothermal sphere parameters, models with zero FLRW spatial curvature fit better as the free parameter approaches an unphysical empty universe, |$\Omega _{\mathrm{M}0}\rightarrow 0$|⁠. By contrast, the timescape cosmology is found to prefer parameter values in which its cosmological parameter, the present void fraction, is driven to |$f_{\mathrm{v}0}\rightarrow 0.73$| and closely matches values that best fit independent cosmological data sets: supernovae Ia distances and the cosmic microwave background. This conclusion holds for a large range of seed values |$f_{\mathrm{v}0}\in \lbrace 0.1,0.9\rbrace$|⁠ , and for timescape fits to both timescape and FLRW mocks. Regardless of cosmology, unphysical estimates of the distance ratios given from power-law lens models result in poor goodness of fit. With larger data sets soon available, separation of cosmology and lens models must be addressed. [ABSTRACT FROM AUTHOR]

This review examines the advances and applications of metal–organic frameworks (MOFs) in the field of the extraction of uranium from various sources, focusing on their potential to address critical issues in nuclear fuel cycles. MOFs, characterized by their high surface area, tunable porosity, and chemical versatility, offer a promising alternative to traditional extraction methods. The review paper provides a comprehensive analysis of the synthesis strategies, functionalization techniques, and adsorption mechanisms of MOFs tailored for uranium capture. Furthermore, the review discusses the challenges and future directions in the field, emphasizing the need for scalable production, real-world application testing, and environmental impact assessment. This review aims to highlight the potential of MOFs to improve the sustainability and efficiency of uranium extraction processes. [ABSTRACT FROM AUTHOR]

Yttrium-based metal–organic frameworks built on hexanuclear clusters (Y6-MOFs) represent an important subgroup of MOFs that are assembled from Y6 clusters and diverse organic linkers, featuring a variety of topologies. Due to the robust Y–O bonds and high connectivity of hexanuclear SBUs, Y6-MOFs are generally thermally stable and resistant to water. Additionally, their pore structures are highly tunable through the practice of the reticular chemistry strategy, resulting in excellent performance in gas adsorption and separation related applications. Y6-MOFs are structurally analogous to Zr6-MOFs; however, the existence of charge-balancing cations in Y6-MOFs serves as an additional pore structure regulator, enhancing their tailorability with respect to pore shape and dimensions. In this Frontier article, we summarize the main advances in the design and synthesis of Y6-MOFs, with a particular focus on the precise engineering of their pore structure for gas separation. Future directions of research efforts in this field are also discussed. [ABSTRACT FROM AUTHOR]

A wide range of applications of unsaturated hydraulic conductivity is well known in geotechnical, hydrological, and agricultural engineering fields. The standard prediction models for hydraulic conductivity function overlook the complexity of soil pore structure and employ a simplistic approach based on the bundle of capillary tubes. This study proposes an alternative approach employing pore network models calibrated to match soil water retention data to predict the hysteretic hydraulic conductivity function of granular soils. A novel approach to constructing a multidirectional pore network built on an irregular lattice with variable coordination numbers is presented for the realistic representation of soil voids. The geometric and topological parameters of the pore network model are optimized using the genetic algorithm, and adequate pore‐scale processes (piston‐like advance and corner flow during drainage and piston‐like advance, pore body filling, and snap‐off during imbibition) are modeled to get reasonable predictions of hysteretic hydraulic conductivity functions over the entire suction range of granular soils. Comparisons between the pore network model results, standard physically based models, and measured data for a variety of granular soils show that the proposed pore network has a superior performance over other models and compares favorably to the experimental data. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Advanced functionalization‐decorated porous organic polymers (POPs) are emerging as a prominent research focus, spanning from their construction to applications in gas storage and separation, catalysis, energy storage, electrochemistry, and other areas. Furthermore, the inherent organic nature, tailored pore structures, and adjustable chemical components of POPs offer a versatile platform for the incorporation of various metal active sites. Meticulously designed molecular building blocks can serve as organic ligands uniformly distributed throughout POPs, leading to the effective isolation of inorganic metal active sites at the molecular level. In this manner, POPs containing active metal centers bridge the gap between organic and inorganic scaffolds. This review aims to provide an overview of recent research progress on metal‐decorated POPs, focusing on strategies for incorporating metal active sites into POPs and their applications in adsorption, separation, catalysis, and photoelectrochemistry. Finally, current challenges and future prospects are discussed for further research. Key Scientists: Advanced functionalized porous organic polymers have become a new research hotspot, ranging from their construction to their use in gas storage and separation, catalysis, energy storage, electrochemistry, and other applications. In 2002, the McKeown group was the first to report phthalocyanine‐based MPOPs with permanent porosity and a moderate surface area. In 2010, the Yu group prepared nanoporous polyporphyrin materials P(Fe‐TTPP) from the metallated porphyrin with functionalized thiophenyl groups by the FeCl3 catalyzed oxidation couple reaction showing the surface area of 1522 m2·g–1. Subsequently, in 2013, the Deng group was the first to use metalated salens as the original building blocks for preparing MPOPs. The Morin group was the first to produce a series of ferrocene‐based nanoporous frameworks via radical polymerization, with surface areas ranging from 385 to 899 m2·g–1. In 2016, the Han group synthesized two N‐pyridinylphenylcarbazole (PPC) ligands to produce a series of metalized polycarbazole networks. Recently, the Tan group reported a solvent‐knitting hyper‐cross‐linking reaction to produce HUST‐1, which contains a porphyrin unit. The porphyrin moiety provides a centered square‐planar metal post‐coordination site, resulting in the metalated HUST‐1‐Co, which exhibits high efficiency in the catalytic conversion of CO2. Additionally, the Kegnæs group combined the decomposition of the palladium complex with an in situ catalyzed polymerization reaction, enabling the confinement of nascent Pd particles in the developing polymer network. This review focuses on recent research progress in metal‐decorated POPs, emphasizing strategies for incorporating metal active sites into POPs and their applications. [ABSTRACT FROM AUTHOR]

Geopolymers represent a distinct class of materials characterised by their X-ray amorphous nature and nanoporous, nanoparticulate structure. Geopolymers can be conveniently mixed, poured, and cured under ambient conditions. This makes this class of materials an interesting alternative to ordinary Portland cement for structural processes. Additionally, the addition of alumina can improve mechanical properties, while the addition of glass can form an impermeable glaze which could be useful for molten salt containment. Therefore, in this investigation, potassium metakaolin-based geopolymer composites with varying proportions of glass particles and alumina platelets were fabricated, cured, heat-treated, and analyzed to study the effects of composition on material properties. Various attributes including rheological properties, densities, mass loss, shrinkage, and porosities were compared. It was observed that certain compositions exhibited high viscosities, making high shear mixing challenging, while also displaying significant permeability that would hinder their ability to contain liquids without leakage. Additionally, certain samples showed reduced densities, suggesting potentially weaker mechanical properties; however, the investigation did not include a direct assessment of mechanical properties. The most promising candidates for containing liquids at high temperature contained 50 wt% KGP, 25 or 35 wt% glass powder, and 25 or 15 wt% alumina platelets, respectively. ASH-G slurries required a minimum of 65 vol% KGP to produce a homogenous material compatible with additive manufacturing. The minimum amount of glass phase to form surface glazes was 16 vol%. Only samples containing more glass phase than alumina phase produced glazed composites. [ABSTRACT FROM AUTHOR]

The main purpose of this work is to explore the nonlinear static bending analysis of functionally graded porous sandwich plates with a ceramic core (FSCC) subjected to a transverse uniform load resting on Kerr foundation (KF) using the mixed interpolation of tensorial components for the four-node rectangular element (called MITC4). Porosity appearing in two skin layers is assumed according to the uneven porosity distribution with a porosity factor Ω. The advantage of this element is fast convergence, high accuracy and cancels the shear-locking phenomenon. The present study considers the geometrical nonlinearity resulting from mid-plane stretching based on the von Kármán geometrical nonlinearity. The first-order shear deformation theory (FSDT) is employed to approximate the displacement field of the plate due to its simplicity and efficiency. The current formulation's authenticity is evaluated by comparing it with previously published works. For the first time, the nonlinear bending of FSCC subjected to a transverse uniform load resting on the Kerr foundation is investigated. Furthermore, the influence of input parameters on the nonlinear bending behavior of FSCC is fully provided. [ABSTRACT FROM AUTHOR]

This research problem is an investigation of reflection amplitude in a nonlocal porous-thermo-micropolar diffusion half-space under memory dependent derivative (MDD) thermo-elasticity subjected to impedance boundary reflecting surface. The governing equations for nonlocal porous-thermo-micropolar diffusion medium in MDD theory are formulated. This research challenge is solved analytically for a two-dimensional model in order to demonstrate the presence of four coupled longitudinal waves and two paired transverse waves denoted as coupled longitudinal displacement wave ( cLDW − I ), coupled longitudinal thermal wave ( cLDW − II ), coupled longitudinal mass diffusion wave ( cLDW − III ), coupled longitudinal void volume fraction wave ( cLDW − IV ), and coupled transverse displacement wave ( cTDW ) and coupled transverse micro-rotational wave ( cTMW ). When there is nonlocality, diffusion, and porous characteristics in the medium, it is discovered to have an impact on these coupled longitudinal waves, making them dispersive and attenuating. The transverse wave is non-attenuating but dispersive, it is unaffected by diffusion and porous characteristics. To find the expression for the reflection coefficients of reflected waves, the plane wave reflection from a thermally insulated surface subjected to an impedance boundary is explored. For a specific material, the reflection coefficients of the reflected waves are calculated, and graphic representations of the fluctuations of the reflection coefficients versus the incidence angle, nonlocality, diffusion and porous constants are provided. For further investigation, energy ratio can be studied in future. [ABSTRACT FROM AUTHOR]

Metal–organic framework (MOF) membranes with apparent molecular sieving effects have great potential for gas separation. However, their application in light‐gas separation (e.g., CO2/CH4 and H2/CH4) remains challenging due to their enlarged pore structures under transmembrane pressure. In this work, a series of MOF membranes constructed from dual‐wing (DW) ligands including 2‐chloromethylbenzimidazole, 2‐methylbenzimidazole, 2‐ethylbenzimidazole, and 2‐phenylbenzimidazole are reported, to finely tune apertures and enhance molecule sieving property for small‐size gases. These DW‐ligands provide steric resistance in two directions perpendicular to the coordination bond, leading to a much finer pore structure. The introduction of the DW‐ligands endows the DW/ZIF‐8 membranes with an adjustable bottleneck door for regulating gas diffusion, blocking the transport of large‐sized CH4 while allowing small‐sized H2 and CO2 to permeate. The membranes show significantly improved molecular sieving property with a CO2/CH4 mixed‐gas selectivity of 58.6 in the case of 2‐chloromethylbenzimidazole23/ZIF‐8, which represents the highest value among the reported ZIF membranes. This membrane also exhibits exceptional separation performance for H2/CH4 and H2/C3H8 with separation factors of 430 and 34341, which are the highest values among the reported MOF membranes. This study presents a facile and efficient strategy for regulating MOF aperture and constructing high‐performance membranes for natural gas separation. [ABSTRACT FROM AUTHOR]

Zeolites, with their well‐defined pore sizes and outstanding stability, are regarded as the quintessential material for precise molecular separation tasks. However, the leap from easily produced zeolite powders to synthesizing free‐standing zeolite membranes, which can fully leverage their ordered porosity, presents substantial technical hurdles. Addressing this challenge, this study introduces polymers of intrinsic microporosity (PIM‐1) as adhesives through a wrapping‐compression method for the facile fabrication of high‐performance and free‐standing zeolite (FAU) “particle board” membranes. The 3D tomogram reconstruction from the focused ion beam‐scanning electron microscope images reveals the “particle board” membranes exhibit hierarchical porous structures. The non‐interconnecting macropores between zeolite particles facilitate the rapid H2 permeation, and the zeolites’ ordered micropores sieve the gas molecules. The optimized FAU@PIM‐1 free‐standing membrane with hierarchically pore structures demonstrated hydrogen permeance (2240 GPU) alongside H2/CH4 selectivity (31.68) for mixed gas and maintained this performance level under pressure ranges from 1.2 to 4.0 bar and over protracted operational periods (up to 3200 h). Meanwhile, EMT and MFI‐type zeolites have also been successfully applied to validate the versatility of this method, demonstrating its widespread potential for the fabrication of various free‐standing zeolite membranes. [ABSTRACT FROM AUTHOR]

Adsorbents‐based gas separation technologies are regarded as the potential energy‐efficient alternatives towards current thermal‐driven methods, and the study on multi‐component gas separation is essential to deepen our understanding of the adsorbents for practical use. Relative to the ideal two‐component mixtures, both the adsorption behavior and separation mechanisms are obviously more complex in multiple gas mixtures due to their close or even overlapped sizes and properties. The emergence of metal–organic frameworks with controllable pore size and pore chemistry provides the platform for the tailor‐made pore structure to satisfy the harsh requirements of multi‐component gas separation. This minireview highlights the recent advance of multi‐component gas separation using metal–organic frameworks, including multiple impurities removal and selective molecular capture. Combining with the typical cases of hydrocarbon separations (C2, C4, and C8), the detailed discussion about the developed strategies (e.g. self‐adaptive binding sites, multiple binding spaces, synergistic binding sites, synergistic sorbent separation technology, gate‐opening effect, size and thermodynamic combine effect) that are adaptive to different scenarios would be provided. The review will conclude with our perspective on the existing barriers and the future direction of this topic. [ABSTRACT FROM AUTHOR]

This study deals with the elimination of methyl orange (MO) from an aqueous solution by utilizing the 3D electroFenton process in a batch reactor with an anode of porous graphite and a cathode of copper foam in the presence of granular activated carbon (GAC) as a third pole, besides, employing response surface methodology (RSM) in combination with Box-Behnk Design (BBD) for studying the effects of operational conditions, such as current density (3–8 mA/cm² ), electrolysis time (10–20 min), and the amount of GAC (1–3 g) on the removal efficiency beside to their interaction. The model was veiled since the value of R² was high (>0.98) and the current density had the greatest influence on the response. The best removal efficiency (MO Re%) at pH = 3 was 95.62% with an average energy consumption of 6.22 kWh/kg MO, which was achieved under maximal conditions of current density = 5.12 mA/cm², mass of GAC = 3 g, and time = 20 min with small amounts of Fe2+ (0.124 mM), and Na2 SO4 (0.02 M). Moreover, the present work investigated the effectiveness of 3D electro-Fenton assisted by ultrasound known as Sono-ElectroFenton (SEF), by following a new strategy based on applying the minimum circumstances of EF and comparing its results with that of SEF under the same conditions. MO Re% for EFmin was 49.24% while SEF was 50.51%, which is considered an exiguous improvement. However, using copper foam as a working electrode in the 3D EF system for the degradation of MO was an excellent choice. Furthermore, the suggested approach is characterized by simplicity, speed, and efficiency with a high percentage of pollutant removal, in addition to being eco-friendly. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Advanced functionalization‐decorated porous organic polymers (POPs) are emerging as a prominent research focus, spanning from their construction to applications in gas storage and separation, catalysis, energy storage, electrochemistry, and other areas. Furthermore, the inherent organic nature, tailored pore structures, and adjustable chemical components of POPs offer a versatile platform for the incorporation of various metal active sites. Meticulously designed molecular building blocks can serve as organic ligands uniformly distributed throughout POPs, leading to the effective isolation of inorganic metal active sites at the molecular level. In this manner, POPs containing active metal centers bridge the gap between organic and inorganic scaffolds. This review aims to provide an overview of recent research progress on metal‐decorated POPs, focusing on strategies for incorporating metal active sites into POPs and their applications in adsorption, separation, catalysis, and photoelectrochemistry. Finally, current challenges and future prospects are discussed for further research. Key Scientists: Advanced functionalized porous organic polymers have become a new research hotspot, ranging from their construction to their use in gas storage and separation, catalysis, energy storage, electrochemistry, and other applications. In 2002, the McKeown group was the first to report phthalocyanine‐based MPOPs with permanent porosity and a moderate surface area. In 2010, the Yu group prepared nanoporous polyporphyrin materials P(Fe‐TTPP) from the metallated porphyrin with functionalized thiophenyl groups by the FeCl3 catalyzed oxidation couple reaction showing the surface area of 1522 m2·g–1. Subsequently, in 2013, the Deng group was the first to use metalated salens as the original building blocks for preparing MPOPs. The Morin group was the first to produce a series of ferrocene‐based nanoporous frameworks via radical polymerization, with surface areas ranging from 385 to 899 m2·g–1. In 2016, the Han group synthesized two N‐pyridinylphenylcarbazole (PPC) ligands to produce a series of metalized polycarbazole networks. Recently, the Tan group reported a solvent‐knitting hyper‐cross‐linking reaction to produce HUST‐1, which contains a porphyrin unit. The porphyrin moiety provides a centered square‐planar metal post‐coordination site, resulting in the metalated HUST‐1‐Co, which exhibits high efficiency in the catalytic conversion of CO2. Additionally, the Kegnæs group combined the decomposition of the palladium complex with an in situ catalyzed polymerization reaction, enabling the confinement of nascent Pd particles in the developing polymer network. This review focuses on recent research progress in metal‐decorated POPs, emphasizing strategies for incorporating metal active sites into POPs and their applications. [ABSTRACT FROM AUTHOR]

After a coal seam is mined, the oxidized coal left in its goaf is prone to water immersion, and spontaneous combustion accidents involving water-immersed coal may easily occur when mining the underlying coal seam. Using scanning electron microscopy and nitrogen adsorption experimental methods, the physical structure of high-temperature pre-oxidized water-immersed coal samples was characterized. By means of infrared spectroscopy, electron spin resonance (ESR) and simultaneous thermal analysis, the microscopic characteristics of the coal samples and the endothermic and exothermic characteristics of the oxidative combustion process were studied. The results showed that a specific pre-oxidation soaking time generated more oxidation pores in the coal sample, causing more water to become trapped in the pores and increasing the secondary oxidation heat absorption. High-temperature oxidation promoted the conversion of coal sample functional groups (FG) and free radical active sites, Water immersion led to the formation and loss of FG, and the longer the water immersion time was, the greater the loss. The larger average pore size of the pre-oxidized water-immersed coal sample provided more coal-oxygen contact sites, and the breaking of chemical bonds in the FG during the secondary oxidation process accelerated the heat release and promoted the oxidative re-ignition of the coal sample. The spontaneous combustion of water-immersed coal in the goaf can be prevented by controlling the high oxidation temperature and water immersion time. [ABSTRACT FROM AUTHOR]

Highly porous and lightweight aerogels of cellulose nanofibers (CNFs) have emerged as a promising class of material. This study delves into the impact of the composition (lignocellulose nanofibers–LCNFs and CNFs) and the drying methods (supercritical drying and freeze-drying) on the morphology and the properties of nanocellulose-based aerogels. The investigation evaluates the concentrations of nanofibers and the influence of lignin, a constituent of LCNFs recognized for enhancing the rigidity of plant cell walls, on the aerogel's properties. The shrinkage rates, density, pore structure, and mechanical properties of the obtained aerogels are comprehensively compared. Supercritical drying proves advantageous for aerogel formation, resulting in materials with lower density and higher surface area than their freeze-dried counterparts at each concentration level. The use of acetone for supercritical drying contributes to reduce the shrinkage rates compared to ethanol. This decrease is attributed to the formation of a more rigid hydrogel during solvent exchange. Freeze-drying exhibits the lowest shrinkage rates and relatively higher porosity. The presence of lignin in the nanofibers influences the microstructure, yielding smoother and thicker pore walls. This study contributes to the comprehensive understanding of the intricate factors shaping nanocellulose aerogel properties, paving the way for the development of innovative and environmentally-friendly materials. [ABSTRACT FROM AUTHOR]