Blind Pores Research Articles

Enhanced Cellular Uptake through Nanotopography‐Induced Macropinocytosis

AbstractEfficient cellular uptake of biomolecules, including genetic material, mRNA, proteins, and nanoparticles, requires novel approaches to overcome inherent cellular barriers. Here, the study investigates how nanotopographical cues from nanoporous surfaces impact the uptake efficiency by cells. The results demonstrate notable enhancements in cellular uptake efficiency across a range of vectors when cells are exposed to nanoporous surfaces. The uptake process is found to be dependent on the size and morphology of the nanopores, reaching a peak efficacy with blind pores of 400 nm in size. Enhanced genetic transduction on nanoporous surfaces are observed for multiple vectors, including lentiviruses, baculoviruses, and mRNA molecules. The versatile nature of this approach allows co‐transfection of cells with multiple mRNA vectors. Moreover, the nanoporous platform is used for efficient and fast manufacturing of Chimeric Antigen Receptor (CAR)‐T cells through lentiviral transduction. Furthermore, the study pinpoints macropinocytosis as the predominant mechanism driving increased cellular uptake induced by the nanoporous surfaces. The introduced method for enhancing genetic transduction of cells has applications in immunotherapy research, drug delivery, and cell engineering.

Pore structure of tight sandstones with differing permeability: The He 8 Member of the Middle Permian Lower Shihezi Formation, Gaoqiao area, Ordos Basin

AbstractTight sandstone has strong pore heterogeneity and complex pore structure, and the pore structure of tight sandstone varies with different permeability. To study the differences in the pore structure of tight sandstone with different permeability, this study investigated the tight sandstone of the He 8 Member in the Gaoqiao area of the Ordos Basin. Factors influencing pore formation are analyzed through experiments utilizing methods, such as distinguishing casting thin sections, scanning electron microscopy, high‐pressure mercury intrusion, and low‐temperature nitrogen adsorption. The results indicate that in this area, the pores of the tight sandstone are primarily dissolution and intercrystalline pores, with occasional intergranular pores and microcracks. Type Ⅱ samples (permeability > 0.2 × 10−3 μm2) are primarily composed of dissolution and intercrystalline pores, with a few visible intergranular and microcracks. In contrast, Type Ⅰ samples (permeability < 0.2 × 10−3 μm2) mainly consist of micropores and intercrystalline pores, where microcracks are observed locally. Pore size research demonstrates that Type Ⅰ samples have pore size under 1000 nm, with peaks primarily at 4–5 nm. There are also peaks between 10–1000 nm, but without a consistent pattern. For Type Ⅱ samples with sizes smaller than 1000 nm, pore distribution is evident. Peak values when the pore size exceeds 1000 nm. Type Ⅰ samples have fewer micron‐level pores, while Type Ⅱ samples are primarily dissolution pores. The nanopores of Type Ⅰ samples consist of flat pores with good connectivity, whereas those of Type Ⅱ samples are mainly blind pores with poor connectivity. Type Ⅰ samples have larger pore fractal dimensions, more intricate pore morphology, and rougher and irregular pore throat surfaces compared to Type II samples. Hence, the sedimentary environment, diagenesis, and mineral composition affect the pore distribution in tight sandstone. The research findings highlight the variations in the pore structure of tight sandstone with varying permeability, providing crucial guidance for classifying and assessing pore structure in tight sandstone reservoirs.

A new method to calculate the effect of fracturing fluid imbibition on adsorbed gas content for shale gas reservoir

In-situ methane occurrence in shale gas reservoirs is seriously affected by the massive imbibed fracturing fluid. However, it is difficult to quantify the impact degree due to the complexity of pore connectivity. In this study, we firstly evaluated the ratio of through and blind pores by a proposed method firstly. Then the different influences of imbibition on gas occurrence in through and blind pores were demonstrated through designed experiments and a visual computational simulation. Finally, a new analytical model was proposed to calculate the effect of imbibition on adsorbed gas content, based on the ratio of through and blind pores and their different imbibition phenomenon. The comparison of the calculation and experimental results showed: (1) the new method can accurately predict the impact degree of imbibition on adsorbed gas; (2) imbibition in through pores leads to the co-current and countercurrent imbibition, and imbibition in blind pores leads to a compression of free gas.

Three-Phase Fluid Flow Interaction at Pore Scale during Water- and Surfactant-Alternating Gas (WAG/SAG) Injection Using Carbon Dioxide for Geo-Sequestration and Enhanced Oil Recovery

Sequestration of CO2 in geologic formations such as depleted oil reservoirs has emerged as one of the lead solutions to tackle greenhouse gas emissions to reduce pollution and global warming. Supercritical CO2 (sc-CO2) injection in oil reservoirs has proven to be useful as an enhanced oil recovery (EOR) technique along with the benefits of CO2 sequestration. In this study, a tortuous microscopic pore scale model was used to study and investigate the phenomena of water-alternating gas (WAG) and surfactant-alternating gas (SAG) with sc-CO2. The study scrutinizes the dynamics of the pore-level phenomenon in the multiphase WAG and SAG flows at the pore level in detail. Transient computational fluid dynamics (CFD) analysis was used to study the fluid flow characteristics of oil, water, and sc-CO2 at different reservoir pressure and temperature conditions in oil-wet conditions. Governing equations were coupled with EOS (Helmholtz free energy equation) to capture the viscous and intrinsic properties of sc-CO2 due to variations in pressure and temperature conditions. It was found that higher oil recovery does not necessarily indicate higher sc-CO2 sequestration and that temperature harms the displacement mechanism due to unfavorable mobility ratios. Comparing WAG and SAG for the first injection cycle, SAG showed a more diffused interface between displaced and displacing fluid. The additional oil recovery produced in patches was a result of pressure oscillations near the blind pores. Moreover, high vorticity promotes greater intermixing between the displacing and displaced fluid by increasing the rate of interface length. In SAG cases, faster sc-CO2 breakthroughs were observed due to reduced shear stress along the fluid interfaces, which resulted in higher sequestration values in a given time frame. The CO2 sequestration volume in SAG cases was found to be approximately 40% more than in WAG experiments. The study confirms that lower values of oil–water interfacial tension aids in faster and more efficient sequestration of sc-CO2 along with additional oil gain from a given reservoir.

Simulation of Gas-water Two-phase Micro-scale Flow in Tight Sandstone Reservoir

China is rich in tight gas reservoir resources, but the production of tight gas wells is greatly affected by water production. In order to further explore the law of tight gas two-phase flow and improve the recovery ratio of a single well. Based on the Lattice-Boltzmann method (LBM), this paper establishes a gas-water two-phase Lattice-Boltzmann model of tight sandstone reservoir, simulates the micro-scale flow of tight sandstone reservoir, clarifies the occurrence law of gas-water in Production layer, and studies the micro-scale flow mechanism of the tight gas reservoir. The results show that the irreducible water of tight sandstone reservoirs mainly has four modes of occurrence: blocking water, blind pore water, dead-end pore water and adsorbed liquid film. Residual gas mainly exists in rock pore throats in three forms: dead-end pore gas, narrow-throat pore gas and closed gas. At the initial stage of two-phase infiltration flow, the liquid phase exists in the form of an adsorption liquid film, which affects the gas phase flow by reducing the flow area of the gas phase. In the middle and late stages, the liquid phase mainly blocks the throat in the form of droplets, thus affecting the gas phase flow. The tight sandstone reservoir is affected by capillary force, liquid-solid viscosity, pore throat structure and other reasons, which are easy to cause water lock damage and seriously reduce the single well production and recovery ratio of tight gas reservoirs. Fracturing is an effective means to improve the overall seepage capacity of tight reservoir fluid. With the increase of fracture width, continuous liquid films on both sides of the fracture restrict the cross-flow between fracture and matrix, further strengthening the water lock damage of the matrix.

Molecular Understanding on Migration and Recovery of Shale Gas/Oil Mixture through a Pore Throat

Shale gas/oil remaining in blind pores accounts for a large proportion in total reserves, which is urgent to be further exploited. Understanding the microscopic mechanism of gas/oil extraction from blind pores is critical to enhanced gas/oil recovery. In this study, we investigated the migration and recovery behavior of shale gas/oil mixture through a pore throat connecting blind pores and microfractures. Our simulations show that some oil molecules tend to migrate in the form of clusters, which increases their effective size and causes possible blockage of the pore throat. The recovery ratio of gas/oil mixture has a strong dependence on the pore size. Below the critical size, which is smaller than the size of oil clusters, the pore throat would be blocked and the recovery ratio will decrease significantly. The heavy fractions of shale oil suppress the extraction of gas/oil molecules from blind pores by four inhibition mechanisms: edge adsorption, surface adsorption, throat blockage, and liquid bridge. The kerogen pore shows a stronger adsorption ability for gas/oil mixture than quartz pore, resulting in more residues in it. We also found that a higher gas/oil ratio can provide a larger driven force, leading to a higher recovery of methane and light fractions. These findings advance the understanding of the recovery mechanisms of remaining gas/oil in blind pores and provide a practical guideline on shale gas/oil exploitation.

Revealing the Effects of Water Imbibition on Gas Production in a Coalbed Matrix Using Affected Pore Pressure and Permeability

The effect of water imbibition on characteristics of coalbed methane reservoirs, such as permeability, gas occurrence state, and gas production, is controversial. According to the mechanism of imbibition, gas and water distribution in blind pores is reconfigured during the fracturing process. Therefore, a new comprehensive model of pore pressure and permeability, based on the perfect gas equation and the weighted superposition of viscous flow and Knudsen diffusion, was established for micro- and nanoscale blind pores during water drainage. Using the numerical simulation module in the Harmony software, the effects of imbibition on coal pore pressure, permeability, and gas production were analyzed. The results showed that (1) water imbibition can increase pore pressure and reduce permeability, and (2) water imbibition is not always deleterious to gas production and estimated ultimate reserve (EUR), when the imbibition is constant, the thicker water film is deleterious to coalbed methane wells; when the thickness of water film is constant, more imbibition is beneficial to gas production and EUR. This research is beneficial to optimize the operation of well shut-ins after fracturing and provides methods for optimizing key parameters of gas reservoirs and insights into understanding the production mechanism of coalbed methane wells.

A new dynamic imbibition model for penny-shaped blind pores in shale gas well

Penny-shaped blind pores are common in shale, these pores with the original gas occurrence, including free gas and adsorbed gas, are seriously affected by a large amount of imbibed fracturing fluid. The competitive gas–water adsorption mechanism and the equations of gas-water phase pressures were analyzed statistically to detail the changes in gas–water distribution during imbibition. Based on the Lucas–Washburn equation, a new dynamic imbibition model is established for penny-shaped blind pores in shale gas reservoirs, which first considers the resistance of desorption of adsorbed gas and free gas and the factors of pore shape and fractal characteristics. The experimental validation, dimensionless-type curve, and common features of the new model regarding water imbibition are analyzed in detail. The results indicated that the proposed model is suitable for accurately predicting the imbibition in blind pores, and the dimensionless-type curve can simplify the calculation process for imbibition predictions. Factor analysis showed that penny-shaped pore width and length are two important factors for imbibition, the smaller width and the longer length, the more imbibition. Meanwhile, the increase of gas-water interfacial tension and displacement pressure is conducive to imbibition, the increase of initial gas pressure and desorption of adsorbed gas is obstructive to imbibition. The research is not only applicable in shale gas reservoir but also useful for geological hydrogen storage, carbon dioxide storage and geothermal development.

Determination of the key structural factors affecting permeability and selectivity of PAN and PES polymeric filtration membranes using 3D FIB/SEM

Microfiltration (MF) and ultrafiltration (UF) processes are well known in water treatment or separation of valuable biomolecules. They have recently been adapted for microalgae valorization, where filtration employing nanoporous polymer membranes is used to separate and recover lipids and proteins from microalgae extracts. As the design of novel MF and UF membranes with optimized filtration performance (reduced fouling of molecules and increased filtrate fluxes) is leading to increasingly complex pore structures, new characterization methods of filtration membranes are needed. A detailed, nanometer scale, characterization of the three-dimensional pore structure of the membranes and the precise elucidation of the membrane’ structure-performance relationship is thus essential for advancing the development of efficient filtration process operating but also novel MF and UF membranes. In this work, the structural features determining the filtration performances of commercially available polyacrylonitrile (PAN) UF and polyethersulfone (PES) MF membranes are determined using scanning electron microscopy (SEM) coupled with a focused ion beam (FIB) at low electron-doses to produce 3D reconstructions with up to 5 nm resolution. Here, methods to identify key structural parameters of the selective layer or skin of the membranes and to estimate the percentage of blind (dead-end) pores communicating with the membrane surface but not crossing the membrane are presented. Furthermore, the data obtained also indicates that widely used models such as Hagen-Poiseuille equation are insufficient to fully describe asymmetric membranes defined by the presence of a thin selective layer. This work opens up the possibility of providing detailed information, useful not only to illustrate novel filtration membrane designs, but also as input data for more complete nanometer-scale based predictive models.

New filtration parameters from X-ray computed tomography for tight rock images

New parameters are proposed to evaluate the filtration properties of rocks obtained on the basis of 3D interpretation of images from X-ray computed tomography. The analyzed parameters are: global average pore connectivity, average blind pore connectivity, blind pore coefficient per object and blind pore coefficient per branch. The 3D pore space from computed X-ray tomography must be subjected to a process of pore space transformation into a skeleton. Then, the presented parameters can be evaluated, taking into consideration the pore channels (branches), pore channel connection points (junctions) and blind pores (pore without connection to the other pore). The calculations were made for low porosity sandstones, mudstones, limestones, and dolomites which differ in terms of age and depth of present deposition. The global average pore connectivity reflects the degree of development of the pore space in which the formation fluid can flow. The higher the global average pore connectivity, the most complex the pore structure can be expected. The higher the parameter of the average blind pore connectivity, the worse are the filtration properties of the rock. The higher the concentration of blind pore coefficient per object or branch, the worse the filtration properties of the rock. Moreover, new parameters were compared with the Euler characteristic and coordination number, revealing a high consistency.

Laser transmission welding of PMMA to alumina ceramic

In this paper, a method of laser transmission welding on ceramic surface after pulse laser microtexture pretreatment was proposed to address the problem that welding ceramics with high transparency polymers is demanded but difficult to be performed. In this method, the polymer flows into the micro-texture of the blind hole on the surface to form mechanical riveting to enhance the welding strength. The formation characteristics and welding mechanism of PMMA welded joint with micro-texture alumina ceramics were studied experimentally and simulatively. The effects of blind hole microtexture size, continuous laser power and continuous laser scanning rate on solution flow and welding strength were studied. The results showed that the air bubbles formed in the welded seam by entering the micro-texture blind hole and trapped air in the blind hole were the key factors affecting the strength of the joint. A 3D finite element model of the transient temperature field and flow field of polymer during laser welding was established. The simulation results showed that the polymer on the left side of the blind hole melted first when heated and inflowed along the wall due to the effects of self-gravity and buoyancy caused by temperature differences. The gas expanded and extruded upward to the left, forming bubbles in the polymer melt pool and pushing the polymer melt into the blind pore microtexture. Finally, a complete molten pool was formed. The flow of polymer melt, the formation of bubbles and the formation of joint were revealed.

Screening of core filter layer for the development of respiratory mask to combat COVID-19

The severe outbreak of respiratory coronavirus disease 2019 has increased the significant demand of respiratory mask and its use become ubiquitous worldwide to control this unprecedented respiratory pandemic. The performance of a respiratory mask depends on the efficiency of the filter layer which is mostly made of polypropylene melt blown non-woven (PP-MB-NW). So far, very limited characterization data are available for the PPE-MB-NW in terms to achieve desired particulate filtration efficiency (PFE) against 0.3 µm size, which are imperative in order to facilitate the right selection of PP-MB-NW fabric for the development of mask. In present study, eight different kinds of PP-MB-NW fabrics (Sample A–H) of varied structural morphology are chosen. The different PP-MB-NW were characterized for its pore size and distribution by mercury porosimeter and BET surface area analyzer was explored first time to understand the importance of blind pore in PFE. The PP-MB-NW samples were characterized using scanning electron microscopy so as to know the surface morphology. The filtration efficiency, pressure drop and breathing resistance of various PP-MB-NW fabric samples are investigated in single and double layers combination against the particle size of 0.3, 0.5 and 1 µm. The samples which are having low pore dia, high solid fraction volume, and low air permeability has high filtration efficiency (> 90%) against 0.3 µm particle with high pressure drop (16.3–21.3 mm WC) and breathing resistance (1.42–1.92 mbar) when compared to rest of the samples. This study will pave the way for the judicial selection of right kind of filter layer i.e., PP-MB-NW fabric for the development of mask and it will be greatly helpful in manufacturing of mask in this present pandemic with desired PFE indicating considerable promise for defense against respiratory pandemic.

Atterberg limits fail in recognizing fragipan horizons

Fragipan is a subsurface soil horizon characterized by high bulk density, coupled with an abundance of fine, blind pores. We hypothesized that this distinctive porosity pattern could affect the Atterberg limits, with significant deviations from those of otherwise comparable soil horizons. Additionally, longer pre-wetting times might be needed to determine the liquid and plastic limits in fragipan, due to restrictions in water movements. Based on these hypotheses, our research focused on (1) assessing the most suitable fragipan-specific sample preparation time for liquid and plastic limit determination; (2) evaluating if the Atterberg limits reflect the presence of fragic properties; (3) exploring the relationships between Atterberg limits and other relevant soil properties through Artificial Neural Networks. Fragipan horizons (F) had a slightly higher liquid limit, much higher bulk density, and specific surface area than nonfragipan (NF). The plastic limit was however comparable for F and NF. Thus, fragipans had a larger interval of plasticity, which is in contrast with slaking tests and well-known field evidence. Despite the expected differences between F and NF, three hours’ pre-wetting was enough for all samples. This might be due to the size fraction used in the analysis, more sensitive to collapse upon water saturation than bigger clods. Atterberg limits did not help in discriminating F from NF, despite the relevant differences in other soil physical properties. Neural Networks showed that the transition from the plastic to the liquid state was mainly driven by texture and specific surface area, while the plasticity interval was mainly affected by the bulk density. These results provided further insights into the mechanical properties of fragipan horizons.

Effect of polystyrene characteristic on photocatalytic hydrogen production by porous polystyrene photocatalyst film under simulated solar light irradiation

In this study, we developed a polystyrene-platinum/nitrogen-doped titanium dioxide/strontium titanate composite-polyvinylpyrrolidone (PS-PNS-PVP) photocatalyst film, which is applied in the process of photocatalytic hydrolysis under simulated sunlight to produce hydrogen, is developed. PS, which is cheap, non-toxic, with high UV resistance, and chemical inertness, is used as a carrier, and a highly effective hydrogen production of Pt/N–TiO2/SrTiO3 as a photocatalyst. The influence of the PS concentration on the stability, optical, and electrical properties of the photocatalyst film is discussed. In addition, the influence of the photocatalyst dispersion in the film on the activity under various photocatalyst concentrations was investigated. A polyvinylpyrrolidone pore-forming agent was then used to examine the effect on the photocatalyst film structure and optical properties, and the subsequent influence on photocatalytic hydrogen energy activity. Adjusting the PS concentration to 20 wt% produced good film-forming stability, and the photocatalyst dispersibility in the film under different photocatalyst concentrations. A photocatalyst concentration of 2.5 wt% resulted in good film dispersibility and the realization of added pore-forming agent. The modified photocatalyst film changed the film from a blind pore structure to a connecting void structure, increasing the film's porosity and hydrophilicity. This increased the number of photocatalytic sites, and the optimal hydrogen production of the photocatalyst film reached 21,333 μmol h−1 g−1.

An experimental study on change of gas permeability depending on pore structures in three species (hinoki, Douglas fir, and hemlock) of softwood

The purpose of this study is to analyze the pore structure for the heartwood, intermediate wood, and sapwood sections in three species of softwood (hinoki, Douglas fir, and hemlock) and to investigate the correlation of gas permeability depending on pore structure. For this study, gas permeability and pore size were measured by capillary flow porometry, and classification of a novel method was performed to determine the type of pores (through pores, blind pores, and closed pores) based on International Union of Pure and Applied Chemistry (IUPAC). Gas permeability, through pore porosity, and pore size increased from heartwood to sapwood. The results of multiple regression analysis showed that through pore porosity, mean pore size, and bulk density were significant factors affecting gas permeability.

Electrospun poly(lactic acid) nanofiber mats for controlled transdermal delivery of essential oil from Zingiber cassumunar Roxb

A controlled release system of Plai (Zingiber cassumunar Roxb.) oil based on electrospun poly(lactic) acid (PLA) nanofiber mat was successfully developed. The physicochemical properties of the nanofibers loaded with select amounts of oil (15%, 20%, and 30% wt) were characterized using various techniques, including a morphological study using scanning electron microscopy (SEM), structural determination using Fourier transform infrared spectrometry (FTIR) and x-ray diffraction (XRD), as well as thermal properties study using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The loading content and the entrapment efficiency of Plai oil within the fiber mats were evaluated and were found to be remarkably high, ensuring that PLA was an appropriate material for Plai oil loading. The ability of the nanofiber mats to release (E)-1-(3,4-dimethoxyphenyl) butadiene (DMPBD) was also examined and the fiber mats showed controlled release characteristics. As the nanofiber mats have particularly high specific surface area with fully accessible and interconnected pore structures, a liquid medium with active ingredients will not be trapped in blind pores but can be fully released out of the fiber matrix. Furthermore, in vitro skin permeation of the active compound as well as a skin irritation were assessed using reconstructed human epidermis (EpiSkinTM). It was found that DMPBD could efficiently penetrate through the skin model. Moreover, the nanofiber mats containing Plai oil also showed no skin irritation, indicating them as promising prototypes for medical applications.

Petrophysical Signatures and Water-Reservoir Potential of Southern Apennines Turbiditic Sandstones Suites

After the seismic event of Irpinia (Southern Apennines), occurred on November 23rd 1980, the Pavoncelli tunnel, that used to supply with water the Puglia Region, was seriously damaged. Because of the strategic importance of this civil engineering work, a new water tunnel named Pavoncelli-bis that should substitute the previous one, was built and finally tested during the end of the 2019. The geological features of the area, highlighted the presence of three main siliciclastic formations (Corleto, pre-Numidian/Numidian and Castelvetere formations), crossed by the tunnel trace, that were petrophysically analyzed through the mercury injection porosimetry for a better definition of their petrophysical signatures and related water-reservoir potential at regional scale as hydrocarbon-reservoir potential. Data highlighted the presence of two clusters: one represented by the Corleto and Pre-Numidian Fms. showing good permeability (respectively 181.70 mD and 122.25 mD in median) and low porosity (respectively 4.56 % and 3.94 % in median); the other, represented by the Castelvetere Fm. highlighting good porosity (9.58 % in median) and a very low permeability (4.84 mD in median). Permeability, more than porosity, affects the cluster differentiation, whereas the other variables (average pore diameter and nanopores volume) do not show any particular trend. All these petrophysical parameters were compared with the sandstone composition (Qm, F, Lt), highlighting that porosity results negatively correlated to monocrystalline quartz (Qm) and positively correlated with feldspars (F). The lithic fragments values (Lt) are sparse and do not show any specific trend. The variability of porosity is directly linked with the diagenetic processes that interested the clusters of the Corleto and pre-Numidian Fms. (rich of Qm) and the Castelvetere Fm. (rich of F). Particularly, where quartz is more abundant, quartz cementation and overgrowth are more efficient and widespread, resulting in a reduction of the porosity. On the contrary, where feldspars are abundant, during diagenesis their dissolution can create new pore spaces and also clay-minerals with a better porosity than the previous feldspars. Moreover, clay-minerals can coat the quartz grains present in the sandstones inhibit the porosity loss of the quartz cementation and overgrowth. However, despite an increase in porosity, permeability decreases because the authigenic clays is mainly formed by isolated and blind pores.

Changes in gas permeability and pore structure of wood under heat treating temperature conditions

In this study, changes in gas permeability and pore structure of wood are evaluated after heat treatment with temperatures ranging from 190 to 230 °C for 6 h for both hardwood (yellow poplar: Liriodendron tulipifera) and softwood (Korean red pine: Pinus densiflora). The purpose of this study is to investigate changes in pore size, content of three pore types (through pore, blind pore, and closed pore), as defined by IUPAC, and gas permeability by increasing heat treatment temperatures in hardwood and softwood using capillary flow porometry and gas pycnometry. As the heat treatment temperature increased, only through pore porosity increased, causing an increase in gas permeability.

Pore Characterization in Cross Section of Yellow Poplar (Liriodendron tulipifera) Wood

This study was conducted to analyze the pore structure of Yellow poplar. Cross-sectional surfaces of heartwood and sapwood of Yellow poplar (Liriodendron tulipifera) were observed by SEM, and the true density of the heartwood, intermediate wood and sapwood were measured by gas pycnometery, while gas permeability and pore size of heartwood, intermediate wood and sapwood were measured by capillary flow porometery. The pores were classified as through pore, blind pore and closed pore. It was determined that the permeability was increased due to the content and size of through pore being increased although the total porosity of specimen showed slight difference from pith to bark. The content of through pore porosity was 33.754 % of heartwood and 47.810 % of sapwood, showed an increasing trend from pith to bark, however, those for the blind pore porosity and closed pore porosity were 27.890 % and 19.492 % for heartwood and 19.447 % and 4.660 % for sapwood, showed a decreasing trend from pith to bark. The max pore size of specimens was increased by about 5 times from 5.927 μm to 31.334 μm, and mean flow pore size was increased by about 315 times from 0.397 μm to 12.437 μm from pith to bark.

Direct determination of amorphous number density from the reduced pair distribution function

The inference of amorphous bulk density, while straightforward for nonporous, soluble materials, may present a formidable challenge in some of the most important classes of industrial applications, involving melts, porous solids, and non-soluble organic pharmaceuticals, with varied implications depending on the material’s level of technological interest. Within nanotechnology and the life sciences in particular, accurate determination of amorphous true density is a frequent requirement and a regular puzzle, when, e.g., neither the Archimedean principle nor gas pycnometry may be applied, the former being only applicable to insoluble compounds, while the latter yielding skeletal density – an overestimate of true density to the extent of blind pores – and its efficiency is affected by the choice of the gas medium. In these cases, it is feasible to infer amorphous density from diffraction experiments through the use of the reduced Pair Distribution Function (PDF). Although an estimate of crystalline density has been known to be possible via the PDF shape, here we outline a new method extending this facility to include the estimation of amorphous density.•Amorphous density may be inferred from the position of a local minimum of the reduced PDF profile, the latter extracted via a Fourier transformation of collected diffraction intensity.•The PDF minimum is located within the PDF range bounded by rmin = 2π/Qmax and the position of the first coordination peak, where Qmax is the maximum length of the scattering vector achieved in the diffraction experiment.•Amorphous density is calculated as the ratio of the value of the reduced PDF at the local minimum, divided by the term 4πr, where r is the real space coordinate of the local minimum.