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Copyright of Journal of Railway Science & Engineering is the property of Journal of Railway Science & Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Geology & Exploration is the property of Xian Research Institute of China Coal Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Although introducing high porosity in biomedical Ti alloys can reduce their elastic modulus and promote new bone ingrowth, relieving the stress–shielding effect and implant failure, this also causes a decline in the alloys' mechanical strength. In this work, a new preparation method for the high–strength and high–porosity Ti65Nb23.33Zr5Ta1.67Fe5 (TNZTF, at.%) alloy was suggested by sintering nanocomposite powder precursor in combination with the use of a space holder technique, in which NH4HCO3 is adopted to achieve a porous structure. The highly porous TNZTF alloy possesses a homogeneous fine–grained microstructure consisting of equiaxed α–Ti and a small amount of FeTi2, the latter of which is distributed in the β–Ti matrix. Through adjusting the mass fraction of NH4HCO3, a novel high–porosity, and high–strength TNZTF alloy with a low modulus was successfully prepared. The porous alloy with the addition of 30 wt.% NH4HCO3 exhibits a porosity of 50.3 ± 0.2%, a maximum strength of 327.3 ± 2.1 MPa, and an elastic modulus of 12.2 ± 0.3 GPa. The strength enhancement is mainly attributed to the unique fine–grained microstructure, which is obtained by the crystallization of the amorphous phase and the ductile–brittle mixed fracture mechanism. The prepared porous TNZTF alloy possesses higher mechanical strength and well–matched elastic modulus, showing great potential as an implant material. [ABSTRACT FROM AUTHOR]

Copyright of China Rural Water & Hydropower is the property of China Rural Water & Hydropower Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Sciencepaper is the property of China Sciencepaper and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Natural Gas Geoscience is the property of Natural Gas Geoscience and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To improve their permeability,porous Si3N4 ceramics were prepared using Si powder as the raw material,Y2O3 and CaF2 as sintering aids,and polymethyl methacrylate microspheres (5 and 20 μm) as pore-forming agents, gel-casting, binder-removing, and finally reaction sintering at 1 650 °C for 3 h in a nitrogen atmosphere. The effects of the particle sizes and additions (volume fractions of 0,15%, 30%, 45%, and 60%) of the pore-forming agents on the apparent porosity,pore size distribution,pore structure and permeability coefficient of the porous Si3N4 ceramics were studied. The results show that: (1) the samples with pore agents exhibit dual pore structures, which are composed of stacking-derived pores and spherical evolution pores, with bimodal pore size distribution; (2) with the same particle size,as the pore-forming agent addition increases,the apparent porosity and permeability coefficient of the samples increase,while the bulk density, bending strength, and fracture toughness decrease; (3) at the same addition, the samples with the smaller-sized agents (5 μm) have higher apparent porosity,permeability coefficient,and bending strength;using smaller-sized pore-forming agents can reduce the thickness of the pore walls and enlarge the pore sizes of the stacking-derived pores within the pore walls,thus enhancing the permeability of the pore walls; (4) the sample with 60% pore-forming agents of 5 μm has the best comprehensive performance,with the apparent porosity of 55.1%,permeability coefficient of 11.62x10-14 m² and bending strength of 35.3 MPa. [ABSTRACT FROM AUTHOR]

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Sand production is one of the challenges facing the oil industry. This paper reviews the latest research advances in chemical sand control and aims to provide a reference for related researchers. Firstly, the commonly used chemical sand control materials are introduced. Second, recent advances in chemical sand control are reviewed, including materials, methods, and processes. Third, laboratory methods for sand control research are presented. Finally, the gaps and challenges of chemical sand control materials are pointed out, and possible future directions for chemical sand control methods are envisioned. [ABSTRACT FROM AUTHOR]

Froth flotation, a prevalent technique for the separation of fine materials, is employed in the decarburization process of coal gasification fine slag (CGFS). This process is known to consume significant quantities of reagents. This study investigates the pronounced variance in collector consumption during the flotation decarbonization of two distinct CGFS samples, where a tenfold difference was observed when the tailings ash content surpassed 95%. A comprehensive set of analyses, including XPS, BET, SEM, wettability tests, LF-NMR and IGC-SEA, was conducted on the residual charcoal from CGFS to elucidate the mechanism behind reagent consumption. The findings reveal that the reagent’s ability to alter the surface hydrophobicity of residual charcoal is contingent upon the adsorption saturation of micropores and transition pores. Furthermore, variations in porosity and surface energy significantly impact collector consumption, independent of differences in the type and quantity of oxygen-containing functional groups. This investigation aims to provide a theoretical framework for reducing the dosage of reagents in the flotation decarburization of CGFS. [ABSTRACT FROM AUTHOR]

Taking the Longmaxi deep-marine shale gas reservoir in Zigong region as the research target, this paper aimed to characterize the nano-scale pore structure and investigate the reservoirs' heterogeneity based on fractal theory. By conducting a series of experimental studies, mainly including TOC, XRD, gas adsorption (N2 and CH4), we were able to clarify the main controlling factors for the heterogeneity of deep shale pore structure. Our results indicated that the deep marine shale possessed a significant amount of organic matter, as the average TOC value is 3.68%. The XRD analysis results show that quartz and clay were the main mineral types, and the total content of these two minerals averaged 77.5%. Positive correlations were observed between TOC and quartz, while TOC decreases as the clay mineral increases, this discovery indicating that quartz is biogenic. Based on FHH (Frenkele-Halseye-Hill) method, by using the LTNA adsorption isotherms, we took relative pressure P/P0 = 0.5 as the boundary, then two separate fractal dimension were deduced, D1 and D2 represent the fractal characteristics of small and large pores, respectively. Our study revealed that both D1 and D2 demonstrated positive correlations with N2 adsorption pore volume and adsorption specific surface area, while negatively correlated with the adsorption average pore diameter. Moreover, the two fractal dimensions showed positive associations with TOC and quartz and negative associations with clay. Additionally, D1 and D2 also demonstrated a positive correlation with Langmuir volume. The presence of micropores was found to significantly influence the formation of an irregular pore structure in shale. As the pore size decreased, the adsorption specific surface area increased, resulting in a more intricate pore structure, and the fractal dimension of the pores elevated, ultimately. This intricate structure is beneficial for the accumulation of shale gas. These research findings offer valuable insights for the comprehensive assessment of deep shale gas, and enrich our knowledge of enrichment mechanisms in deep shale gas reservoirs. [ABSTRACT FROM AUTHOR]

In cold areas, the steel fiber reinforced rubber concrete (SFRRC) pavement is exposed to natural environment and experiences varying degrees of damage from freezing and thawing. This can have a serious impact on the normal usage and safe operation of the pavement structure. This research examines the impact of varying rubber concentrations on multiple variables, such as the rate of mass reduction, relative dynamic modulus of elasticity, compressive strength, and thickness of the damage layer (Hf) during freeze–thaw (F-T) durability testing conducted on SFRRC. Furthermore, an analysis is conducted to determine the degradation pattern exhibited by SFRRC. The internal structure evolution and pore structure characteristics of SFRRC were examined using scanning electron microscopy and mercury intrusion porosimetry techniques, which revealed the underlying damage mechanism in SFRRC during F-T cycles. The results suggest that the addition of an appropriate amount of rubber can effectively enhance the frost resistance of SFRRC in water. A gradual improvement in the frost resistance of SFRRC is observed when increasing the rubber content from 0 to 10%. The optimal frost resistance is observed in SFRRC with 10% rubber content. However, when the rubber content reaches 15%, SFRRC exhibits significant degradation and lower level of resistance to freezing compared to SFRRC without rubber. Microcracks form within SFRRC due to the freezing–thawing forces experienced during the experiment, resulting in the development of a damage layer that extends from the surface to the interior. The compressive strength of the damaged layer significantly decreases as Hf increases. The addition of appropriate rubber in SFRRC improves its pore structure, leading to an increased proportion of harmless or less harmful pores and a reduction in average pore size, thereby significantly enhancing its frost resistance. [ABSTRACT FROM AUTHOR]

In this work, the preparation of titanium sponge by magnesium thermal method is regarded as the liquid-phase sintering process of titanium, and powder-metallurgy sintering technology is utilized to simulate the aggregation–growth and densification behavior of titanium particles in a high-temperature liquid medium (the molten Mg-MgCl2 system). It was found that compared with MgCl2, Mg has better high-temperature wettability and reduction effect, which promotes titanium particles to form a sponge titanium skeleton at lower temperature. The aggregation degree of titanium particles and the densification degree of a sponge titanium skeleton can be improved by increasing the temperature and the relative content of Mg in the melting medium. The kinetics study shows that with the increase in temperature, the porosity of the titanium particle aggregates and the sponge titanium skeleton decreases, and their density growth rate increases. With the extension of time, the aggregation degree of titanium particles and the densification degree of sponge titanium gradually increase. This work provides a theoretical reference for controlling the density of titanium sponge in industry. [ABSTRACT FROM AUTHOR]

The purpose of this study is to prepare monodisperse silica mesoporous microspheres with narrow pore size distribution to promote their application in the field of liquid chromatography. An improved emulsion method was used to prepare silica mesoporous microspheres, and the rotary evaporation temperature, emulsification speed, dosage of porogen DMF, and dosage of the catalyst NH3·H2O were optimized. Subsequently, these microspheres were respectively treated by alkali–heating, calcination, and sieving. The D50 (particle size at the cumulative particle size distribution percentage of 50%) of as–prepared silica mesoporous microspheres is 26.3 μm, and the D90/D10 (the ratio of particle size at a cumulative particle size distribution percentage of 90% to a cumulative particle size distribution percentage of 10%) is 1.94. The resultant silica mesoporous microspheres have distinctive pore structures, with a pore volume of more than 1.0 cm3/g, an average pore size of 11.35 nm, and a median pore size of 13.4 nm. The silica mesoporous microspheres with a large particle size, uniform particle size distribution, large average pore size and pore volume, and narrow mesopore size distribution can basically meet the requirements of preparative liquid chromatographic columns. [ABSTRACT FROM AUTHOR]

Coalbed methane represents a promising source of clean and efficient unconventional energy. The intricate network of micro–nano pores within coal serves as the primary adsorption space for gas, contributing to the complexity of gas migration channels. In this study, based on the box-counting method, three coal samples representing low, medium, and high ranks were subjected to high-precision micro-CT scanning and nano-CT scanning to generate three-dimensional (3D) pore network models using Avizo visualization software. This facilitated the accurate and quantitative characterization of the micro–nano pore structures within coal reservoirs. The results indicated that the face rate distribution range of each sample was large, indicating relatively strong heterogeneity in each sample. The volume fractal dimension of each sample, determined through micro–nano-CT scanning, was around 2.5, while the surface fractal dimension exhibited oscillatory characteristics with moderate uniformity. The pore equivalent radius and throat equivalent radius distributions were unimodal across all the samples, with the micro-CT scanning revealing a concentration primarily within the range of 100–400 μm for the pore equivalent radius and within 200 μm for the throat equivalent radius. Conversely, the nano-CT scanning exhibited concentrations primarily within the range of 500–2500 nm for the pore equivalent radius and within 2000 nm for the throat equivalent radius. The analysis of the 3D reconstruction structures indicated that the middle-rank coal exhibited more developed large–medium pores compared with the low-rank and high-rank coal, while the low-rank and high-rank coal exhibited relatively more micro–small pores. Furthermore, the low-rank coal exhibited the fewest number of pores but the largest average pore equivalent radius and throat radius. Additionally, the middle–high-rank coal exhibited a relatively larger number of pores. Despite the complex topological structures observed in each sample, a significant proportion indicated a coordination number of 0–20, indicating excellent connectivity within the coal samples. This study is conducive to the optimization of coalbed methane surface development blocks and the formulation of reasonable development plans. [ABSTRACT FROM AUTHOR]

Unconsolidated sand reservoirs containing heavy oil play a significant role in hydrocarbon resources, characterized by high porosity and permeability alongside abundant movable fines. During production, these fines can detach and migrate with the reservoir fluids, causing pore plugging and reduced productivity. Visualizing and quantitatively evaluating the evolution of pore structure caused by fines migration under various influencing factors at the microscale is fundamental for devising effective prevention and mitigation measures. This study employs on-line NMR experiments and CFD-DEM simulations to investigate fines migration processes and their effects on physical properties and pore structure at the pore scale. Results indicate that fines migration initiates the formation of a preferential network of migration pathways. The evolution of pore structure demonstrates zonal characteristics along the flow direction, with fines plugging and residual accumulation primarily occurring in the middle/rear section of the core. As the core's skeleton porosity decreases, fines plugging intensifies; however, at high injection velocity, new dominant flow channels may emerge, leading to a transition from a single-peak to a double-peak T2 spectrum. Below the critical velocity (0.5-1 mL/min), an increase in flow velocity exacerbates severe fines plugging. Conversely, above the critical velocity, an increase in flow velocity results in a more pronounced enhancement of permeability. [ABSTRACT FROM AUTHOR]

Phenanthrene (PHE) is a polycyclic aromatic hydrocarbon categorized as a high priority organic pollutant being toxic for the ecosystem and human health, and its sorption on natural organic or inorganic substances seems a well-promising method for its removal from water streams. The goals of the present work are (i) to assess the capacity of low-cost adsorbents fabricated by treating coffee wastes and diatomaceous earth to remove PHE from water; (ii) to elucidate the role of the pore structure on PHE sorption dynamics; and (iii) to assess the potential to regenerate adsorbents loaded with PHE, by using the novel technology of cold atmospheric plasma (CAP). Diatomaceous earth (DE) and DE pre-treated with sodium hydroxide (NaOH) or phosphoric acid (H3PO4) were chosen as inorganic adsorbents. Coffee waste (CW) and activated carbons (AC) produced from its pyrolysis at 800 °C (CWAC), either untreated (CWAC-800) or pre-treated with NaOH (CWAC-NaOH-800) and H3PO4 (CWAC-H3PO4-800), were chosen as organic adsorbents. The adsorbents were characterized with nitrogen adsorption–desorption isotherms, attenuated total reflectance-Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, and mercury intrusion porosimetry. Based on the PHE sorption capacity and pore structure/surface characteristics, the CWAC-NaOH-800 was chosen as the most efficient adsorbent for further equilibrium and kinetic sorption studies. The multi-compartment model was used to describe the PHE sorption dynamics in CWAC-NaOH-800 by accounting for the pore/surface diffusion and instantaneous sorption. The CWAC-NaOH-800 exhibited remarkable values for (i) the specific surface area (SBET = 676.5 m2/g) and meso- and micro-pore volume determined by nitrogen sorption (VLN2 = 0.415 cm3/g); (ii) the macro- and meso-pore volume determined by mercury intrusion porosimetry (VMIP = 3.134 cm3/g); and (iii) the maximum PHE sorption capacity (qmax = 142 mg/g). The percentage of adsorbent recovery after its regeneration with CAP was found to be ~ 35%. From the simulation of sorption dynamics, it was found that at early times, the sorption kinetics is governed by the film diffusion towards the external surface of grains, but at late times, most of the adsorbed mass is transferred primarily to meso-/macro-pores via diffusion, and secondarily to micro-porosity via surface diffusion. Based on the adsorbent characteristics, effect of pH on sorption efficiency, and numerical analysis of sorption dynamics, it was concluded that probably the dominant adsorption mechanism is the π-π interactions between hydrophobic PHE aromatic rings and CWAC-NaOH-800 graphene layers. The high PHE removal efficiency of CWAC-NaOH-800, the successful interpretation of sorption dynamics with the multi-compartment model, and the potential to regenerate PHE-loaded adsorbents with the green and economic technology of CAP motivate a strategy for testing CWACs towards the adsorption of other PAHs, application of adsorbents to real wastewaters, and scaling-up to pilot units. [ABSTRACT FROM AUTHOR]

In order to clarify the relationship between the conventional diffusion models and the time-dependent diffusion model during gas desorption, a porous diffusion model during gas desorption in coal was established by modeling the pore structure according to the porous diffusion theory and fractal theory. Gas diffusion processes were experimentally measured using a series of coal samples with different ranks and types under different gas equilibrium pressures. And the established theoretical model was furthermore verified by experimental data. The theoretical data derived from the established porous diffusion model agreed well with the experimental data with correlation coefficients greater than 99.0%. The attenuation of diffusion coefficient during gas desorption was essentially attributed to the gradual decrease of the gas diffusion amount for large pores during unsteady diffusion of gas in porous media. The effective diffusion coefficient presented a first fast and then slow decreasing trend with the prolonged diffusion time. The diffusion coefficient increased with the increase of gas equilibrium pressure as well as the metamorphic grade and fragmentation degree of coal. The pore connectivity enhanced as the surface area proportion of larger pores increased, leading to an increase in the proportion of the gas diffusion quantity in larger pores and the diffusion coefficient and meanwhile a decrease in the fractal dimension. This study will provide theoretical support for in-depth understanding of the gas diffusion mechanism in gas-containing coal. [ABSTRACT FROM AUTHOR]

A study was undertaken into the preparation and properties of fly-ash-based geopolymers that can be used to make multistage-pore materials able to adsorb gases such as carbon dioxide. The influence of steel slag on the mechanical properties and microstructure of the final precursor products was investigated and characterised by mechanical strength tests, X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetry–differential thermal analysis, scanning electron microscopy–energy-dispersive X-ray spectroscopy and mercury intrusion porosimetry. The results showed that a low dose of steel slag significantly promoted the early compressive strength of a multistage-pore geopolymer. However, when the slag dose reached 30%, the strength decreased dramatically. The pore classification effect was more obvious when the capillary pores in the geopolymer disappeared and the pores mainly existed in the form of gel pores and voids. [ABSTRACT FROM AUTHOR]

To address the issue of pavement cracking due to brittle concrete in road and bridge engineering, this study explores the use of high–ductility magnesium phosphate cementitious concrete (HD–MPCC) for rapid repairs. The deformation and frost properties of HD–MPCC are analyzed to assess its suitability for this application. Deformation properties were tested for HD–MPCC specimens cured in both air and water. Subsequent tests focused on the frost performance and mechanical properties after freeze–thaw cycles. A mercury penetration technique was utilized to examine the pore structure. The findings reveal that the expansion deformation of HD–MPCC increases with curing age in both air and water conditions, and the quantitative relationship between the expansion deformation and curing age of HD–MPCC was analyzed. Additionally, the freeze–thaw cycles led to a decrease in mass loss, the relative dynamic elastic modulus, the ultimate tensile strength, the ultimate tensile strain, the flexural strength, and the peak deflection. The volume fraction of harmless and less harmful pores gradually decreased as the freeze–thaw cycle increased, while the volume fraction of more harmful pores increased, resulting in a decrease in the strength, ultimate tensile strain, and peak deflection. [ABSTRACT FROM AUTHOR]

Lamination is the predominant and widely developed sedimentary structure in mudstones. Similar to organic pores in shale gas reservoirs, the inorganic pores in the laminae of shale oil reservoirs are equivalently important high-quality reservoir spaces and flow channels. The laminae characteristics are strongly heterogeneous, being controlled by both deposition and diagenesis. However, the origin of this diversity is poorly understood. A detailed examination of cores, thin sections, and scanning electron microscopy analyses were conducted on the lacustrine mudstone of the Qingshankou Formation in the Songliao Basin to study the influence of deposition and diagenesis on laminae characteristics and their relationship to reservoir quality. Three types of laminae are mainly developed, namely thick siliceous laminae, thin siliceous laminae, and thin siliceous and argillaceous mixed laminae. Deposition controls the type and distribution of laminae. The thin siliceous and argillaceous mixed laminae are controlled by climate-driven seasonal flux variations. The thick siliceous laminae and thin siliceous laminae are controlled by bottom current or gravity-driven transport processes due to increased terrestrial input. The thin siliceous laminae have the optimum reservoir properties, followed by the thin siliceous and argillaceous mixed laminae, while the thick siliceous laminae have the worst properties. Diagenesis controls the pore evolution of the laminae. Different laminae have different paths of diagenesis. The thin siliceous laminae are mainly cemented by chlorite, preserving some primary porosity. The clay mineral content of the thin siliceous and argillaceous mixed laminae is high, and the primary pores are mainly destroyed by the strong deformation of the clay minerals during compaction. The thick siliceous laminae are intensely cemented by calcite, losing most of the porosity. The present study enhances the understanding of reservoir characteristics in laminae and provides a reference for shale oil exploration. [ABSTRACT FROM AUTHOR]

Marine–continental transitional shale has become a new field for shale gas exploration and development in recent years. Its reservoir characteristics analysis lags significantly behind that of marine shale, which restricts the theoretical research on the accumulation of marine–continental transitional shale and the progress of exploration and development. The shale pore system is complex and has strong heterogeneity, which restricts the fine evaluation and optimization of the reservoir. Based on nitrogen adsorption–desorption experiments, the morphology and structural characteristics of coal-bearing shale pores were analyzed, and then the micro-pore structure heterogeneity was quantitatively characterized based on fractal theory and nitrogen adsorption–desorption data, and the relationship between pore structure parameters and their influence on fractal characteristics were discussed. The hysteresis loop of nitrogen desorption isotherm mainly belongs to type B, indicating ink bottle, flat plate, and slit are the main pore shapes. The pore size distribution curves are left unimodal or multimodal, with the main peak around 4 nm and 20–60 nm. Smaller pores develop a larger specific surface area, resulting in a high value of fractal dimension (2.564 to 2.677). The rougher the pore surface and the larger the specific surface area provide an adequate adsorption site for shale gas adsorption and aggregation. Thus, fractal characteristics conduced to understand the pore structure, heterogeneity, and gas-bearing property of coal-bearing shale. [ABSTRACT FROM AUTHOR]

Capillary water absorption is an important parameter to evaluate the durability of cement mortars. For testing the capillary water absorption of cement mortars, drying is a necessary and crucial procedure. However, different standards have different requests on drying temperatures for doing the tests. Since the calcium aluminate cement-hemihydrate gypsum (CAC-C S ¯ H0.5) mortars are temperature-sensitive, three temperatures of 20 °C, 40 °C and 70 °C were selected to study the effect of hydroxypropyl methyl cellulose (HPMC) on the capillary water absorption of these mortars. The influence of temperature on the capillary water absorption of the mortars was analyzed from the perspectives of pore structure and hydration. The results show that when the viscosity of HPMC is the same, the higher the dosage of HPMC used, the higher the capillary water absorption of mortars. When the dosage of HPMC is the same, the higher the viscosity of HPMC, the greater the capillary water absorption of mortars. The addition of HPMC can significantly increase the total porosity of mortars, especially the volume of the large pores. However, pore structure is not the main factor influencing the capillary water absorption of HPMC-modified CAC-C S ¯ H0.5 mortar. When the drying temperature rises to 40 °C, a small amount of AFt is decomposed. When the drying temperature reaches 70 °C, most of AFt is carbonized to form hemicarboaluminate and AH3, and the latter is the key to refining the pore structure of mortars. The temperature change causes a phase transition of the hydration products, thereby altering the pore structure. 40 °C is suggested as an appropriate drying temperature for the capillary water absorption test of the investigated mortars. [ABSTRACT FROM AUTHOR]

The Lower Cambrian shale gas in the western Hubei area, South China has a great resource prospect, but the gas-in-place (GIP) content in different sedimentary facies varies widely, and the relevant mechanism has been not well understood. In the present study, two sets of the Lower Cambrian shale samples from theWells YD4 and YD5 in the western Hubei area, representing the deep-water shelf facies and shallowwater platform facies, respectively, were investigated on the differences of pore types, pore structure and methane adsorption capacity between them, and the main controlling factor and mechanism of their methane adsorption capacities and GIP contents were discussed. The results show that the organic matter (OM) pores in the YD4 shale samples are dominant, while the inorganic mineral (IM) pores in the YD5 shale samples are primary, with underdeveloped OM pores. The pore specific surface area (SSA) and pore volume (PV) of the YD4 shale samples are mainly from micropores and mesopores, respectively, while those of the YD5 shale samples are mainly from micropores and macropores, respectively. The methane adsorption capacity of the YD4 shale samples is significantly higher than that of the YD5 shale samples, with a maximum absolute adsorption capacity of 3.13 cm3/g and 1.31 cm3/g in average, respectively. Compared with the shallow-water platform shale, the deep-water shelf shale has a higher TOC content, a better kerogen type and more developed OM pores, which is the main mechanism for its higher adsorption capacity. The GIP content models based on two samples with a similar TOC content selected respectively from theWells YD4 and YD5 further indicate that the GIP content of the deep-water shelf shale is mainly 3-4 m3/t within a depth range of 1000e4000 m, with shale gas exploration and development potential, while the shallow-water platform shale has normally a GIP content of <1 m3/t, with little shale gas potential. Considering the geological and geochemical conditions of shale gas formation and preservation, the deep-water shelf facies is the most favorable target for the Lower Cambrian shale gas exploration and development in the western Hubei area, South China. [ABSTRACT FROM AUTHOR]

With its unique structural characteristics, hard carbon is considered to be the most promising negative electrode material to promote the industrialization of sodium-ion batteries. In addition to its layer spacing and chemical composition, the sodium storage performance of hard carbon is also closely related to nano pores. Hard carbon with ultra-micro pores, large pore volume, low specific surface area and closed pores can reduce the influence of solid electrolyte interface film on sodium storage and facilitate the embedding/removal of sodium ions. Design and regulation of hard carbon pore structure has become one of the key points to improve the performance of sodium-ion batteries. The pore structure can be effectively controlled by selecting suitable precursor materials, adjusting pyrolysis process parameters (heating rate, pyrolysis temperature), improving pretreatment methods (physical activation, chemical activation), doping heteroatoms, coating and other means. It will be the development direction of sodium-ion batteries in the future to use advanced characterization methods combined with theoretical calculation to realize reasonable design of pore structure of hard carbon materials and prepare low cost, high capacity and high cycle stability negative electrode materials. [ABSTRACT FROM AUTHOR]

Shale matrix permeability is vital to the evaluation of shale petrophysical property. In this study, an analytical model that considers pore size distribution, tortuosity, adsorption, and slippage effects is developed, to calculate the permeability of shale samples. Specifically, field emission scanning electron microscope (FE-SEM), the ImageJ software, and the MATLAB programming and numeric computing environment are employed to experimentally characterize the pore structure and to fit and optimize the pore size distribution. The discrete pore size distributions of organic matter and inorganic matter pores for Longmaxi and Qiongzhusi shale samples are determined based on FE-SEM images. According to the sum of squares error (SSE), coefficient of determination (R2), root-mean-square error (RMSE), and outcome of the fit, the Gaussian 2 correlation function is optimized to fit the continuous pore size distribution. Finally, the permeabilities of five shale rock samples are calculated and compared with the measured results from the Longmaxi and Qiongzhusi Formations. The results illustrate that the multi-term Gaussian fit is more suitable for calculating the permeability of samples with multimodal pore size distributions than the multi-segment Gaussian fit. The calculated results from the pore size distribution are more accuracy than those from the representative mean pore radius. The influence of pore size distribution on permeability and how seepage mechanisms in different pore sizes work together to represent permeability changes at the core scale will be investigated in the future. The study provides a more reliable calculation of the shale matrix permeability compared to previous methods. [ABSTRACT FROM AUTHOR]

Copyright of New Building Materials / Xinxing Jianzhu Cailiao is the property of New Building Materials Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Poly(ether ether ketone) (PEEK) is an important high‐performance engineering polymer that is used extensively in numerous engineering applications that require chemical, solvent and thermal resistance. These attributes make PEEK attractive for the preparation of porous materials and membranes. Chemical modifications of preformed porous PEEK materials can expand the utilization of PEEK in a range of applications. It is desirable to carry out chemical functionalization without affecting the preformed porous structure or the degree of polymer crystallinity responsible for the sought‐after properties. We report here on the heterogeneous functionalization of preformed mesoporous PEEK materials with hydroxyl groups using sodium borohydride as a reducing agent in a poly(ethylene glycol)/tetrahydrofuran solvent mixture. The pore structure of functionalized materials was characterized, and the degree of modification with functional groups was measured as a function of reaction protocol. The methodology was applied to the preparation of porous PEEK materials in the form of beads and hollow fibers that differed in semicrystalline morphology and pore structure. The degree of surface modification by –OH groups in reduced PEEK (PEEK‐OH) porous materials was determined quantitatively by measuring the carbocation adduct concentration formed upon the dissolution of PEEK‐OH in sulfuric acid using UV–visible spectroscopy. Bis(4‐(4‐methoxyphenoxy)phenyl)methanone was used to optimize the reaction condition protocol. The degree of crystallinity and pore structure of the functionalized articles were largely preserved following modification. © 2024 Society of Industrial Chemistry. [ABSTRACT FROM AUTHOR]

Calcium sulfoaluminate belite (CSAB) binder is an alternative low CO2 binder. CSAB cement has ye'elimite as the primary clinker phase which hydrates to form monosulfate or ettringite as the main hydration product. The hydration and mechanical characteristics of CSAB cement and PC-CSAB blended cement have been reported in several studies; however, studies on the durability characteristics such as carbonation are limited. This study focuses on evaluating the microstructural and mechanical alterations due to carbonation in a CSAB binder system and understanding the underlying mechanism of development of the carbonation front. CSAB binder was found to carbonate rapidly compared to PC binder, accompanied by a reduction in compressive strength. This was attributed to the increase in the pore volume due to the carbonation of the ettringite-rich microstructure, facilitating further ingress of CO2 into the microstructure. The rate of carbonation in CSAB binders diverged significantly from the square root of time model used for PC binders. [ABSTRACT FROM AUTHOR]

In order to solve the problem of rapid loss of concrete workability caused by high adsorption of recycled sand, six kinds of recycled sands of C20 ~ C60 were used as objects. The pore structure characteristics of recycled sand were tested by mercury intrusion and low-temperature liquid nitrogen adsorption methods, and the physical composition of recycled sand was tested by X-ray diffraction (XRD). The adsorption law of recycled sand on water, methylene blue, and superplasticizer was explored. The results show that the water absorption rate of recycled sand decreases with the increase of strength grade of waste concrete materials, which is closely related to pore structure. The adsorption of recycled sand on methylene blue decreases with the decrease of clay mineral content, and there is no significant correlation with pore structure. The adsorption of recycled sand on superplasticizer is affected by both pore structure and clay mineral, but mainly depends on clay mineral content. [ABSTRACT FROM AUTHOR]

In order to deal with the problem that the marine concrete with large dosage of mineral admixture in the actual project faces the harsh marine environment prematurely and is easy to be eroded by chlorine salt, this paper proposed to use magnetized water instead of tap water to prepare marine concrete, studied the influence law of magnetized water on the mechanical properties and durability of marine concrete at different ages, and analyzed the microstructure of marine concrete using the mercury instrusion porosimetry and scanning electron microscope. The study shows that magnetized water improves the workability of marine concrete. Compared with tap water, magnetized water has obvious improvement on the early mechanical properties of marine concrete, in which the compressive strength and splitting tensile strength of C50 marine concrete with a curing age of 7 d increase by 17.9% and 16.5%, respectively. Regardless of different curing ages, the resistance to carbonation and chloride ion penetration of magnetized water marine concrete are better than tap water marine concrete. The degree of reaction of cementitious materials in magnetized water marine concrete is higher, with fewer cracks, and the microstructure between cementitious materials and aggregates is more compact. The overall porosity is lower, with more harmless pores and fewer harmful pores, leading to a denser microstructure. Thus the mechanical properties and durability of marine concrete are improved. [ABSTRACT FROM AUTHOR]

There is less research on the mechanical behavior of cement-based materials containing superabsorbent polymers (SAP) under high strain rate. In this paper, the total porosity and macroscopic pore (> 100 µm) porosity of cement-based materials containing SAP were investigated by the use of mercury intrusion and graphical techniques. The effects of SAP particle size and extra water on the quasi-static (10-5 s-1) and dynamic (60 ~ 110 s-1) mechanical properties of the modified materials were analysed. Based on the study of the crack propagation behavior, the damage behavior of the cement-based materials was analyzed under high strain rates. The results show that the addition of extra water and the increase of SAP particle size improve the total porosity and macroscopic pore porosity of the materials, which reduce the compressive strength and elastic modulus of the specimens under quasi-static and dynamic compression. The addition of extra water and the increase of SAP particle size also enlarge the compressive strength dynamic increase factor and elastic modulus dynamic increase factor of the cement-based materials, which is due to the fact that an increase in total porosity and macroscopic pore porosity induces a change in the crack extension path, an increase in fragmentation, and a delay in the strain response. [ABSTRACT FROM AUTHOR]

Re-dispersible latex powder is the key material for the preparation of steel structure interface mortar. In this paper, the influence of the content of re-dispersible latex powder on the 28 d compressive strength, flexural strength and tensile bond strength of interfacial mortar was researched. At the same time, combined with scanning electron microscopy, X-ray spectroscopy and other microscopic analysis methods, the bonding mechanism of re-dispersible latex powder to enhance the interfacial mortar was analyzed. The results show that the suitable content of re-dispersible latex powder is 15% (mass fraction, same below) in the preparation of steel structure interface mortar. Under the appropriate dosage, the tensile bond strength of the interface mortar reaches 1.12 MPa, and the compressive-flexural strength ratio is 2.3. The addition of latex powder can effectively improve the flexibility of the mortar. The addition of latex powder changes the pore structure of the mortar, and the porosity becomes larger. The hydration products in interfacial transition zone are mainly polymer film encapsulated hydration products C-S-H gel and Ca(OH)2. [ABSTRACT FROM AUTHOR]

In order to address the issue of reduced compressive strength in plastic mortar caused by the hydrophobic nature of plastic, this sturdy utilizes the thermoplasticity of discarded polypropylene (PP) plastic to prepare silica fume@ plastic particle composite particles (SF@ PP) by welding silica fume on the surface of PP through the thermal welding process and tests the hydrophilicity and volcanic ash activity of the composite particles. The results indicate that the modified plastic through silica fume heat welding improves the hydrophilicity of PP and enhances its volcanic ash activity, promoting the deposition of hydration products at the interface and increasing the compactness of the interface. Consequently, the porosity of the plastic mortar is significantly reduced, and the compressive strength is significantly increased by 26.07% to 31.04%. The results of the study are conducive to the efficient utilization of waste plastics and provide a basis for the preparation of high-performance plastic mortar. [ABSTRACT FROM AUTHOR]

Driven by capillary adsorption, moisture and aggressive media can easily intrude into unsaturated concrete and shorten the service life of concrete structures. In the present study, gangue-based concrete (GBC) was produced by replacing cement (substitution rate 0%, 10%, 20% and 30%) with mechanical-microwave activated coal gangue powder (ACGP) to explore the effect of freeze-thaw damage on the water absorption performance of GBC. ACGP improved the frost resistance of GBC, but the frost resistance declined at 30% mixing. The water absorption performance of GBC was promoted by freeze-thaw damage. Besides, the water absorption performance of GBC decreased first and then enhanced with the growth of ACGP content, especially the weakest at 20% content. The correlation analysis between the macroscopic characteristics of freeze-thaw damage and water absorption performance suggested that the coefficient of capillary absorption was highly linearly correlated with the damage layer thickness (R2 > 0.9). The pore structure of GBC was optimized by the increase of small pores as well as the decrease of large pores after ACGP mixing. Furthermore, the coefficient of capillary absorption showed an apparent positive correlation with the transitional pores. [ABSTRACT FROM AUTHOR]

In this study, foamed ceramics were successfully prepared using cyanide tailings (CTs) with a high sulfur content as the main raw material. The effects of sintering temperature, holding time, and heating rate on the bulk density, water absorption, porosity, pore structure, and compressive strength of foamed ceramics were systematically investigated. The results showed that the elevated sintering temperature promoted the generation of liquid phases, resulting in an obvious enlargement of the pore size and a decrease in bulk density. In addition, a similar evolution trend could be found in the pore size and bulk density with the extension of the holding time, which was attributed to the degrees of silicon carbide reaction. Foamed ceramics with small pore sizes could be prepared at a heating rate that did not exceed 4°C/min. Then, the higher heating rates could bring abnormally large pores and be detrimental to the mechanical properties of the foamed ceramics, which were proven to be related to the decomposition of FeS2 introduced by CTs during the heating process. In conclusion, the foamed ceramics prepared with CTs in this study provide effective solid waste utilization and have good application prospects in wall composite one-piece insulation panels. [ABSTRACT FROM AUTHOR]

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The study of deep shale gas (>3500 m) has become a new research hotspot in the field of shale gas research in China. In this study, 16 representative deep shale samples were selected from different layers of the Wufeng–Longmaxi Formation in the Z-3 well in the western Chongqing area to conduct low-field nuclear magnetic resonance (NMR) tests, field-emission scanning electron microscopy (FE-SEM) observation, and fractal modeling. By comparing the differences in pore structure and their influencing factors in representative samples from different layers, the particularities of high-quality reservoirs have been revealed. The results show that the Z-3 well shales mainly develop micropores and mesopores, with pore sizes of 1 nm–200 nm. The fractal dimensions of bound fluid pores D1 (1.6895–2.3821) and fractal dimension of movable fluid pores D2 (2.9914–2.9996) were obtained from T2 spectra and linear fitting, and the pores were divided into three sections based on the NMR fractal characteristics. TOC content was one of the major factors affecting the gas content in the study area. The shale samples in the bottom S1l1-1 sub-layer with a higher TOC content have larger porosity and permeability, leading to enhanced homogeneity of the pore structure and favorable conditions for shale gas adsorption. A comparative understanding of the particularities of pore structure and influencing factors in high-quality reservoirs with higher gas content will provide the scientific basis for further exploration and exploitation of the Wufeng–Longmaxi Formation deep shale reservoirs in the western Chongqing area. [ABSTRACT FROM AUTHOR]

Seawater sea-sand concrete (SSC) structures reinforced with fiber reinforced polymer (FRP) bars were proposed to capture CO2 by means of carbonation curing in this study. FRP-SSC structures allowed sufficient carbonation to occur since the steel corrosion in traditional reinforced concrete structures would not exist. Herein, the pore structure of CO2-cured SSC with sufficient carbonation was examined, and the mechanical behaviors under uniaxial compression were also investigated. MIP testing was employed, and surface fractal dimension in various pore-size regions was calculated. The results indicate that CO2 curing leads to a more significant variation in smaller mesopores of SSC than CC. Regarding middle capillary pores, the surface fractal dimension in almost all CO2-cured specimens ranges from 2.6617 to 2.8124, which means that these pores show distinct fractal characteristics, but this phenomenon does not be observed in water-cured specimens. This indicates that CO2 curing can greatly reduce ink-bottle pores in concrete. Furthermore, the compressive strength gain of CO2-cured SSC with sufficient carbonation is above 30% at the 180-days age. The compressive strength gain can be attributed to the improvement in the surface fractal dimension. Moreover, CO2-cured specimens exhibit higher peak stress, smaller peak strain, and greater elastic module, resulting in lower plasticity. Consequently, CO2 curing renders SSC and CC more brittle. [ABSTRACT FROM AUTHOR]

The haulage roadway of the F15-22080 working face, No.8 mine is situated within a special non-uniform stress zone. In this area, the extraction-boreholes drilling process frequently triggers coal and gas outburst. Against this background, this study systematically conducted high-pressure gas adsorption experiments and high-pressure gas desorption experiments on coal samples collected from different stress zones and obtained their adsorption/desorption characteristics. Subsequently, coal pore structure characteristics at various scales were investigated by employing scanning electron microscopy, low-pressure N2 adsorption and low-pressure CO2 adsorption techniques and fractal analysis to assess the impact of varying stress levels. On this basis, a comprehensive analysis was carried out to explore the connections between stress, pore structure, adsorption/desorption traits, and the risk of outburst. The results indicate that, with increasing stress, the Protodyakonov coefficient f and the Langmuir pressure PL decrease, while the index of diffusion initial velocity of coal gas Δp and the Langmuir volume VL increase. The desorption amount and rate of gas also increase significantly. The total pore volume and specific surface area of micropores increase, while those of mesopores and macropores show an overall decreasing trend. The surface fractal dimension DF1 increases by 9%, the spatial fractal dimension DF2 decreases by 5.2%, and the volume fractal dimension DSIE increases by 1%. The induced stress leads to a decrease in the abundance of macropores and mesopores, with concurrent increase in micropores. The VL exhibits a linear increase with the DSIE, whereas the PL demonstrates a linear decrease with it. The initial desorption rate rises with the reduction of the DF2 and the increase of the DSIE. The influence of superimposed-stress on outburst stems from alterations in pore structure and adsorption–desorption capabilities. Simultaneously, it collectively heightened the outburst risk by increasing the gas pressure gradient and weakening the strength of the coal. [ABSTRACT FROM AUTHOR]

Coalbed methane (CBM) mining has always been plagued by low mining efficiency. CBM-rich areas have high mining efficiency, but their formation is affected by CBM seepage. Through on-site mining, it is found that gas seepage in low-permeability areas presents nonlinear characteristics. In this paper, the causes and rules of nonlinear seepage are analyzed. The pore structure characteristic parameters such as pore size distribution, pore proportion and fractal dimension were obtained by nuclear magnetic resonance technology, and the pore structure characteristics of low permeability coal are analyzed. The results showed that the proportion of porosity was 6.30–11.02% and the proportion of percolation pores was 7.52–19.59%. Both total porosity and percolation pores had fractal characteristics. Aiming at the nonlinear problem of gas seepage law in low permeability coal, the permeability and gas flow data of coal samples under different gas pressures were measured by the self-designed coal core permeability automatic tester, and the gas seepage characteristics of low permeability coal samples are studied. The experiment showed that there was a starting pressure gradient in gas seepage in coal samples, and the relationship between gas permeability and gas pressure turned over at 1.25 MPa, indicating that there is a slip effect in coal pores. Considering the influence of pore structure parameters on the nonlinear seepage characteristics of CBM, the relationships between porosity, tortuosity, pore proportion, and fractal dimension and Kirschner permeability, slippage factor, and starting pressure gradient were fitted. The analysis showed that the pore size distribution characteristics with large proportion of micro-pores in low permeability coal made the pressure gradient required for the internal gas seepage larger, the influence of the slippage effect was enhanced, and the seepage of gas was nonlinear. To conclude, the influence of micro-pores developed in low permeability coal on nonlinear gas seepage was significant. [ABSTRACT FROM AUTHOR]

[Objective] To analyze the pore fractal characteristics and interference factors from the coal measure shale of the Taiyuan Formation in the northern Qinshui Basin. [Methods] Total organic carbon (TOC) content, maturity, X-ray diffraction, and low-temperature nitrogen adsorption experiments were conducted on samples of the Taiyuan Formation in the Yangquan block. The fractal dimension of a sample pore was calculated based on the (Frenkel Halsey Hill, FHH) theoretical model, which analyzes the influence of mineral content, organic geochemical characteristics, and pore structure parameters on the pore fractal dimension. [Results] The results show that the TOC content of coal measure shale in the Taiyuan Formation is between 0.57% and 6.40%, and the average is 3.18%; the vitrinite reflectance of organic matter (Ro) is between 1.96% and 3.24%, and the average is 2.49%. The coal-measure shale micropores have double fractal characteristics, of which fractal (D1) is between 2.507 9 and 2.663 9, dimension (D2) is between 2.527 1 and 2.809 4, and the organic matter content and maturity are positively correlated with D1 and D2. The pore structure parameters have a positive correlation with D1 and D2, but the correlation coefficient with D2 is higher than that of D1, indicating that micropores have stronger influence on pore structure parameters. The input of terrigenous clastic quartz with high sorting and roundness leads to regular pore morphology, resulting in a negative correlation between quartz content and D1 and D2. Carbonate minerals and feldspar primarily provide macropores, and their contents are related to shale. Both D1 and D2 are negatively correlated, and the pore size of the clay minerals decreases under long-term compaction, whereas the number of micropores increases, and the pore shape is complex, which is positively correlated with fractal dimensions D1 and D2. Conclusions The micropores of the coal measure shale in marine continental transitional facies have dual fractal characteristics. The increase of organic matter content, maturity, pore structure parameters, and clay mineral content can lead to the increase of micropore fractal dimension, and an increase in terrigenous clastic quartz, feldspar, and carbonate mineral content can lead to a decrease in micropore fractal dimension. [ABSTRACT FROM AUTHOR]

Exposure to heavy metals in water bodies is of environmental concern; hence, their removal is necessary. As-received coals obtained from two sedimentary basins in Nigeria were characterized and tested for their potential application as adsorbent in the removal of lead(II) ions from contaminated water. Physical and chemical properties of the coals including their elemental composition, conductivity, density, pH, pore structure, surface morphology and thermal behaviour were studied using standard instruments and techniques. The removal efficiency of the coals, adsorption isotherms and kinetics were studied from batch experiments. Results showed that the coals possessed adsorbent properties in terms of carbon content, pH, density, surface morphology and pore structure. The removal efficiency of Pb(II) ions from aqueous media using Ogwashi-uku coal ranged from 89.01 to 99.45%, while it ranged from 80.77 to 98.51% with Onyeama coal. Adsorption equilibrium for the removal of lead ions was established at pH of 6, 1 g dosage, at 100 ppm concentration with the contact time of 90 and 75 min for Ogwashi-uku and Onyeama coals, respectively. The adsorption process followed Langmuir isotherm, while the kinetics best fitted the pseudo-second-order model. The adsorption data did not fit Elovich isotherm for chemisorption. Factors such as pore structure, density and morphology influence the ability of a coal to adsorb heavy metals from lead aqueous solution. The availability, adaptability, ease of use, cost effectiveness and environmental considerations recommend the tested raw coals for application in the removal of lead from contaminated water bodies. [ABSTRACT FROM AUTHOR]

To improve the performance of shotcrete in high-altitude and low-temperature environments, emulsified asphalt shotcrete (EASC), which can be used in negative-temperature environments, was prepared by using low-freezing-point emulsified asphalt, calcium aluminate cement, and sodium pyrophosphate as modified materials. The effect of emulsified asphalt on the performance of shotcrete was investigated through concrete spraying and indoor tests. Then, the modification mechanism of emulsified asphalt with respect to EASC was analyzed by combining scanning electron microscopy images and the pore structure characteristics of EASC. The results showed that in a negative-temperature environment, the incorporation of emulsified asphalt delayed the formation of the peak of the cement hydration exotherm, slowed the rate of the cement hydration exotherm, reduced the thermal perturbation of permafrost by EASC, increased the cohesion of the concrete, improved the bond strength between EASC and permafrost, and reduced the rate of rebound. The mechanical strength of the studied EASC decreased upon increasing the amount of emulsified asphalt in the admixture, and its resistance to cracking gradually improved. A content of less than 5% emulsified asphalt could improve the internal pore structure of EASC, thus improving its durability. Increasing the content of emulsified asphalt affected the hydration process of the cement, and the volume content of the capillary pores and macropores increased, which reduced the durability of the EASC. [ABSTRACT FROM AUTHOR]

Copyright of Special Oil & Gas Reservoirs is the property of Special Oil & Gas Reservoirs Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The discovery of a large number of ancient ivory and ivory artifacts in Sanxingdui site has elevated the importance of ancient ivory relics to the level of exploring the origins of Chinese civilization. To clarify the current preservation status of decayed ivory excavated from the Sanxingdui site, we have conducted an in-depth analysis of the structure-water state relationship of the ivory unearthed from the No. 4 sacrificial pit (K4) as an example. The research indicates that the ancient decayed ivory is composed of a mixed phase of hydroxyapatite [HA, Ca10(PO4)6(OH)2] and carbonated hydroxyapatite [CHA, Ca10(PO4)3(CO3)3(OH)2], which has a mixed structure of sheet-like and needle-like crystals. The organic fibrous protein within the ivory has basically disappeared, resulting in a porous structure with a porosity of approximately 39.2%. The pore size distribution is concentrated in the range of 2.5–100 nm, dominated by mesopores, with a handful of micropores. These pore structures are occupied by adsorbed water, free water and bound water, exhibiting a high water content (35%–40%). These water molecules play a filling and supporting role in the pore structure. During the dehydration and deterioration process of the ancient decayed ivory, the loss of water support results in internal stress within the microstructure of the ivory, leading to irreversible damage such as peeling, pulverization and cracking. The correlation study between the pore structure and water state of ancient decayed ivory provides clues for tracing the geological environment, sacrificial rituals, and ecological environments of ivories in ancient times, serving as a crucial window into Earth’s history and biological evolution.

Liquid CO2 enhancing coalbed methane recovery (CO2-ECBM) is an effective and intrinsically reliable gas drainage technology. Injection of liquid CO2 into coal seam has the dual effect of increasing the permeability of the coal and rock and strengthening the recovery of gas, which is manifested primarily as “pressure cracking, low temperature frostbite, physical extraction and chemical corrosion, phase change pressurization, low viscosity permeability, competitive adsorption”. In this paper, the acidification and corrosion of CO2-H2O-coal was studied in physical and chemical extraction by experimental test and comparative analysis. The liquid CO2 acidification reference group and the variable group experiment were designed. On the basis of the pH value of the aqueous solution, the content of major elements and minerals in coal, the minerals involved in chemical reaction, and their specific gravity were deduced. Variation in pore volume, specific surface area, and pore fractal characteristics were quantitatively and qualitatively analyzed. The experimental results show that the higher the pressure, the higher the content of carbonic acid dissolved in water and the amount of H+ ionized by carbonic acid. The longer the reaction time, the greater the mineral content involved in the chemical reaction, and the H+ in the water sample is consumed in large quantities. The elements of Na, K, Ca, Mg, Al, Si, S, P, and Ti decreased with increasing pressure, and the maximum decreases were 0.004 %, 0.024 %, 1.095 %, 0.028 %, 0.220 %, 0.304 %, 0.006 %, 0.003 % and 0.029 %, respectively. The decrease in Ca element was the largest, indicating that Ca-bearing minerals participate in the reaction. Calcite, kaolinite, and illite were the main minerals involved in the chemical reaction of CO2-H2O-coal. The pores (d > 100 nm) and transition pores (10 < d < 100 nm) in the sample were further developed, and the pore volume increased significantly, forming a good gas migration channel. In addition, the number of new micropores (2 < d < 10 nm) increases, the specific surface area increases significantly, and the complexity of the pores increases, forming a good reservoir.

Abstract Liquid manipulation using tubular actuators finds diverse applications ranging from microfluidics, printing, liquid transfer to micro‐reactors. Achieving flexible and simple regulation of manipulated liquid droplets during transport is crucial for the tubular liquid actuators to perform complex and multiple functions, yet it remains challenging. Here, a facile tubular actuator for directional transport of various liquid droplets under the control of an externally applied magnetic field is presented. The surfaces of the actuator can be engineered with submillimeter‐sized through‐hole pores, which enables the liquid droplet to be easily modulated in the transport process. Furthermore, the liquid actuator with featured through‐hole pores is expanded to function as a switch in an integrated external electric circuit by magnetically controlling the motion of a conductive liquid droplet. This work develops a strategy for regulating liquid droplets in the tubular actuation systems, which may inspire ideas for designing functional liquid actuators with potential applications in microfluidics, microchemical reaction, liquid switch, and liquid robotics.

This study investigated the preparation of cementitious mortar specimens (ECM) by blending different dosages of pure magnesium hydroxide (AR), active magnesium oxide, and nano magnesium hydroxide as external additives with expired composite Portland cement. The optimal solution was selected by comparing their “nuclear magnetic resonance” (NMR), mechanical properties, and acoustic emission characteristics. NMR experiments revealed that the addition of 4 wt% nano magnesium hydroxide to expired cement resulted in the largest decrease in harmful pore content in ECM, reaching 21.9%. Mechanical performance testing and acoustic emission monitoring results indicated that the strength of ECM reached a maximum of 21.356 MPa with the addition of 4 wt% nano magnesium hydroxide, representing a 20.2% increase compared to the control group. This suggests that adding 4 wt% nano magnesium hydroxide to expired cement is a preferable option.