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Cement composites containing different carbon nanomaterials, namely graphene technical grade, graphene super grade, and graphene oxide, up to 1.0% by weight of cement, were prepared. Ultrasonic, chemical, and thermochemical treatments were applied to improve the stability of the dispersions containing the graphene-based nanomaterials. Their exfoliation was analyzed using Raman spectroscopy, and the stability of the dispersions was quantitatively investigated by means of the static multiple light scattering (SMLS) technique. The sonication process enhanced the intensity of the 2D band of graphene technical grade, suggesting a partial degree of exfoliation, while the hydrothermal treatment with sodium cholate significantly promoted the stability of its dispersion. The effect of the addition of selected graphene-based nanomaterials in mortars was evaluated in terms of fresh state properties, mechanical strength, capillary water absorption, and pore size distribution. Workability decreased with the increase in the amount of carbon nanomaterials. Field emission scanning electron microscopy (FESEM) was also employed to characterize the microstructure of pristine graphene-based nanomaterials and their inclusion within the cement matrix. Our results suggest that mechanical properties are only moderately affected by the inclusion of all additives, whereas the introduction of graphene significantly influences the coefficient of capillary water absorption. Specifically, a reduction of about 20% in the capillary water absorption coefficient was observed at the concentration of 1.0 wt% of graphene technical grade, which is ascribed to a refinement of the porosity. [ABSTRACT FROM AUTHOR]

In recent years, there has been a growing interest in one-part alkali-activated materials, which utilize solid-form alkali activators, within the construction industry. This approach is becoming popular due to its simpler and safer application for cast-in-situ purposes, as compared to the conventional two-part method. At this purpose, we have pioneered the use of volcanic deposits of Mt. Etna volcano (Italy) as precursor for the synthesis of a unique one-part formulation. This was done to assess its performance against both traditional and two-part alkali-activated materials. The study employed a comprehensive range of investigative techniques including X-ray powder diffraction, Fourier transform infrared spectroscopy, hydric tests, mercury intrusion porosimetry, ultrasound, infrared thermography, spectrophotometry, contact angle measurements, uniaxial compressive strength tests, as well as durability tests by salt crystallization and freeze–thaw cycles. The key findings on the studied samples are as follows: i) small size of pores and slow absorption-drying cycles; ii) satisfying compactness and uniaxial compressive strengths for building and restoration interventions; iii) high hydrophily of the surfaces; iv) lower heating dispersion than traditional materials; v) significant damage at the end of the salt crystallization test; vi) excellent resistance to freeze–thaw cycles. These newly developed materials hold promises as environmentally friendly options for construction applications. They offer a simplified mixing process in contrast to the conventional two-part alkali-activated materials, thus providing an added advantage to this class of materials. [ABSTRACT FROM AUTHOR]

Abstract Understanding the relationship between pumice formation and long-term floatability in seawater is becoming increasingly important in terms of eruption dynamics, material cycles, biological and environmental effects, and ocean hazards. Pumice rafts were produced during the 2021 eruption of the Fukutoku-Oka-no-Ba submarine volcano in the Pacific Ocean, far from the Japanese archipelago. The pumice rafts reached the Amami-Ōshima and Okinawa Islands approximately two months after the eruption and continued to cover the sea surface at several bays and ports, providing a great opportunity to study the characteristics of raft pumices. Sieve analysis of the floating pumice indicated that the pumice rafts characteristically contained several millimeter-sized particles with a peak at 2–4 mm. This evidence raises an important question why the millimeter-sized, Fukutoku-Oka-no-Ba 2021 pumice particles were able to float for over two months, which exceeds the floatation time shown in previous studies. To answer this question, a porosity measurement technique for millimeter-to-centimeter-sized pumice particles was established and applied to drifting pumice that erupted during the Fukutoku-Oka-no-Ba 2021 eruption. The total, connected, and isolated porosities (including errors) were acquired for floating and sunken pumice particles. As studied for the floating pumice from past submarine eruptions, most floating pumice particles contain a high amount of isolated porosity (> 30 vol%) and are thus unsinkable even when the pumice size is in the millimeter scale. This study emphasizes that skeletal density is a useful measure for the determination of pumice floatability (sinkable or unsinkable). As the particle size decreases, crystals are lost from the floating pumice particles, suggesting that the particle size of the floating pumice is affected by its petrological properties (crystal content and size). A comparison with natural pumices from subaerial eruptions and experimental pumices from magma decompression experiments suggests that the Fukutoku-Oka-no-Ba 2021 pumices contain abundant isolated pores due to the suppression of expansion after fragmentation by quenching in seawater, and that the relatively low to moderate crystal content in the magma ( 30 vol%) and are thus unsinkable even when the pumice size is in the millimeter scale.

Understanding the relationship between pumice formation and long-term floatability in seawater is becoming increasingly important in terms of eruption dynamics, material cycles, biological and environmental effects, and ocean hazards. Pumice rafts were produced during the 2021 eruption of the Fukutoku-Oka-no-Ba submarine volcano in the Pacific Ocean, far from the Japanese archipelago. The pumice rafts reached the Amami-Ōshima and Okinawa Islands approximately two months after the eruption and continued to cover the sea surface at several bays and ports, providing a great opportunity to study the characteristics of raft pumices. Sieve analysis of the floating pumice indicated that the pumice rafts characteristically contained several millimeter-sized particles with a peak at 2–4 mm. This evidence raises an important question why the millimeter-sized, Fukutoku-Oka-no-Ba 2021 pumice particles were able to float for over two months, which exceeds the floatation time shown in previous studies. To answer this question, a porosity measurement technique for millimeter-to-centimeter-sized pumice particles was established and applied to drifting pumice that erupted during the Fukutoku-Oka-no-Ba 2021 eruption. The total, connected, and isolated porosities (including errors) were acquired for floating and sunken pumice particles. As studied for the floating pumice from past submarine eruptions, most floating pumice particles contain a high amount of isolated porosity (> 30 vol%) and are thus unsinkable even when the pumice size is in the millimeter scale. This study emphasizes that skeletal density is a useful measure for the determination of pumice floatability (sinkable or unsinkable). As the particle size decreases, crystals are lost from the floating pumice particles, suggesting that the particle size of the floating pumice is affected by its petrological properties (crystal content and size). A comparison with natural pumices from subaerial eruptions and experimental pumices from magma decompression experiments suggests that the Fukutoku-Oka-no-Ba 2021 pumices contain abundant isolated pores due to the suppression of expansion after fragmentation by quenching in seawater, and that the relatively low to moderate crystal content in the magma (< 17 vol%) may contribute to favorable conditions to produce abundant, millimeter-sized, unsinkable pumice. Most floating pumices have lower saturation density than seawater due to abundant isolated porosity (> 30 vol%) and are thus unsinkable even when the pumice size is in the millimeter scale. [ABSTRACT FROM AUTHOR]

Biochar (BC) is often used as an additive in anaerobic digestion (AD) to increase yield and/or to stabilise the process when the manure content is increased. Unfortunately, BC is rarely described in detail in terms of its raw material sources, production processes, and structural, physical and chemical properties to allow correlation with its effects on AD. It is an open question whether microorganisms from AD can penetrate into different biochar pore types, depending on their wood origin. In this paper, we describe the preparation (temperatures, treatment times, yields) and characterisation shrinkage, density, pore sizes, pore size distribution, specific surface area, ash, volatiles, fixed carbon, elemental composition, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), benzene, toluene, ethyl-toluene, xylene (BTEX) and volatile halogenated hydrocarbons (VHH) of BC cubes of Scots pine (Pinus sylvestris) and common beech (Fagus sylvatica) powder made from this BC in addition to commercial charcoal powder. The pore size distribution determined by mercury porosimetry differs from that determined by 3D-reflected light microscopy. After incubating BC cubes in AD, the cubes were mechanically cleaned and cut into two pieces. Microorganisms were detected inside the cubes by fluorescence microscopy. Particle size and wood source determine the influence of BC on AD. [ABSTRACT FROM AUTHOR]

Structural and physicochemical properties of two types of bacterial cellulose (BC) produced by Komagateibacter sucrofermentans strain DSM 15973T after 7 days through either immobilized bacteria (solid inoculum) forming BCS7 or free bacteria (liquid inoculum) forming BCL7, followed by a water-based purification as a chem-free alternative treatment, were investigated in this study. SEM verifies the effectiveness of the water-based purification on BC network and reveals the insufficient interfibrillar space of BCS7 compared to BCL7. BCL7 was generally proved to be superior to BCS7 regarding degree of purification, BC yield, overall higher porosity, water swell ability, and water holding capacity (WHC), exhibiting higher hydrophilicity. However, thermally resistant BCS7 reveals a 35% residual up to 800 ºC compared to BCL7 (15%) and prevailed in terms of water retention rate. Both water-treated BC7 were proved to be Iα-rich cellulose type and exhibited a typical type IV(a) isotherm with an H3 type of hysteresis loop, a similar pore distribution, crystallinity index (~77%), crystallite size (~7.5 cm), same levels of moisture content (~98%) and the same poor levels of rehydration after the freeze-drying process. During BCL kinetics in 20 mL of HS medium over 7 days, K. sucrofermentans, 2D pellicle formation was observed until day 3 and then 3D. The highest WHC was obtained on day 4 (116 g water/g cellulose), while the lowest on day 1 (19 g water/g cellulose). Overall, we discussed the preparation and characterization of two different BCs water-treated for purification as an eco-friendly alternative method towards functional, and sustainable application. [ABSTRACT FROM AUTHOR]

This experimental study investigated the performance of self-compacting concrete (SCC) mixes with magnesia (MgO) waste. In the series produced with a water/binder ratio of 0.40, cement was replaced by magnesia waste at 2%, 4% and 10% by weight in the SCC. Le Chatelier test, slump flow, compressive strength, flexural strength, depth of penetration of water under pressure, ultrasonic pulse velocity and water absorption by capillary testing was conducted to assess sample performance. X-ray diffraction, thermogravimetric analysis, mercury intrusion porosimetry, differential thermal analysis and scanning electron microscopy were used for the microstructural analysis and quantification of phases within each sample. The results indicated that concrete with magnesia waste contains magnesium silicate hydrate (M–S–H) and brucite ((Mg(OH)2) products. Brucite causes strength loss in concrete. Up to 90 days, specimens with magnesia showed increasing compressive and flexural strength. As the amount of magnesia waste increased, the porosity, depth of water penetration under pressure and water absorption by capillary increased. Incorporating more than 10% of magnesia waste in the SCC mixtures resulted in declining strength. The addition of magnesia waste enhanced the expansion of SCC. An optimum dosage (2%) of magnesia waste was the most advantageous to the strength of SCC. [ABSTRACT FROM AUTHOR]

Cement composites containing different carbon nanomaterials, namely graphene technical grade, graphene super grade, and graphene oxide, up to 1.0% by weight of cement, were prepared. Ultrasonic, chemical, and thermochemical treatments were applied to improve the stability of the dispersions containing the graphene-based nanomaterials. Their exfoliation was analyzed using Raman spectroscopy, and the stability of the dispersions was quantitatively investigated by means of the static multiple light scattering (SMLS) technique. The sonication process enhanced the intensity of the 2D band of graphene technical grade, suggesting a partial degree of exfoliation, while the hydrothermal treatment with sodium cholate significantly promoted the stability of its dispersion. The effect of the addition of selected graphene-based nanomaterials in mortars was evaluated in terms of fresh state properties, mechanical strength, capillary water absorption, and pore size distribution. Workability decreased with the increase in the amount of carbon nanomaterials. Field emission scanning electron microscopy (FESEM) was also employed to characterize the microstructure of pristine graphene-based nanomaterials and their inclusion within the cement matrix. Our results suggest that mechanical properties are only moderately affected by the inclusion of all additives, whereas the introduction of graphene significantly influences the coefficient of capillary water absorption. Specifically, a reduction of about 20% in the capillary water absorption coefficient was observed at the concentration of 1.0 wt% of graphene technical grade, which is ascribed to a refinement of the porosity.

Many construction projects worldwide commonly utilize lateritic clays as essential construction materials. These soils require a specific knowledge of their physical and mechanical properties. In this work, scanning electron microscopy (SEM), mercury intrusion porosimetry (MIP), and matrix suction measurements were conducted on lateritic clay. The purpose was to obtain soil water characteristic curves (SWCC) and the influence of suction on the stress–strain behavior of compacted specimens of lateritic clay under zero lateral displacement conditions. The results show that lateritic clay compacted on the dry and wet side of the compaction curve has dual porosity. The mean micropore size is near 19 nm, while macropores have mean sizes of 2.1 µm, 8.4 µm, and 5.4 µm when the specimens are compacted in the dry, optimum, and wet side of the compaction curve, respectively. Also, the SWCC curve has a bimodal shape, in agreement with the MIP results. Matrix suction and the microstructure generated during compaction significantly influence the stiffness of the compacted lateritic clay. The compacted lateritic soil shows stiffening as water content decreases at 800 kPa of 5.95%, 5.3%, and 2.93% for the specimens compacted on the wet, optimum, and dry side of the compaction curve. [ABSTRACT FROM AUTHOR]

An investigation of clay microstructure and its evolution under one-dimensional (1D) and isotropic compression is presented for different clays. Data from the literature are compared to original results on two Italian clays, obtained using scanning electron microscopy, image processing, mercury intrusion porosimetry and on-purpose swelling tests. The effects of composition and loading history on clay microstructure, as well as its changes along the compression path (pre- and post-gross yielding) are analysed and a conceptual model of microstructure evolution is proposed for the clays under study. Normally consolidated clays at early virgin compression, either natural or reconstituted, are found to possess an open fabric of random to low orientation, complying with a prevailing inter-aggregate and a smaller intra-aggregate porosity, whose size and distribution depend on composition. Under 1D compression, either in the field or in the laboratory, the inter-aggregate porosity is lost, at a rate dependent on composition and loading history, and the dominant intra-aggregate micropore is progressively reduced. Accordingly, perfectly oriented stacks of domains are recognised which, however, embed preserved random particle arrangements even at large pressures, resulting in an increase of average orientation up to the reach of a steady orientation degree. Isotropic compression causes faster microstructure evolution, although large pressures are required to change 1D-induced fabric orientation. [ABSTRACT FROM AUTHOR]

Soil collapse is a critical factor contributing to various pathologies in civil construction, necessitating the use of suction-controlled techniques, often unavailable in smaller cities in developing countries. This study investigated the collapsible behavior of clayey sand from Tuneiras do Oeste, Paraná, Brazil, using conventional one-dimensional tests with varied initial moisture contents and pre-soaking stresses. Tests maintained constant specimen moisture, soaked samples at pre-defined stress values (S tests), and observed collapse behavior under gradual wetting (GIM tests). Supplementary mercury intrusion porosimetry (MIP) analyses determined the collapse’s influence on pore size distribution. Collapse indexes were computed, and the Pereira and Fredlund (J Geotech Geoenviron Eng 126:907–916, 2000) model was applied to predict collapsible behavior for GIM tests data, showing strong agreement with experimental results (R2 > 0.98). Additionally, two prediction models developed from different test data also exhibited a high degree of correlation (R2 = 0.97 and 0.95 for S and GIM tests, respectively). It was observed that pre-soaking moisture, i.e., the pre-soaking matric suction, played a crucial role in wetting-induced soil collapse, while pre-soaking stress had a secondary effect. The infiltration rate during soaking impacted the observed collapse, with higher rates resulting in greater collapse magnitudes. Regarding soil structure, collapse led to significant alterations only in the macropores, causing a notable reduction in their diameters. Ultimately, the experimental protocol developed in this study yielded valid results for modeling collapsible soils, even in the absence of sophisticated suction-controlled equipment. [ABSTRACT FROM AUTHOR]

Due to the development of the chemical industry, the need to obtain high-purity monodisperse nanoparticles is increasing. Therefore, it is necessary to choose the right method for obtaining them. The paper demonstrates a unique method, induction flow levitation, which allows a large list of metal nanoparticles to be obtained using one installation. In this work, magnesium nanoparticles are obtained using this method. The morphology is studied using scanning electron microscopy, where the resulting nanoparticles are clusters of primary particles. Energy-dispersive analysis shows that the surface of magnesium nanoparticles after interaction with atmospheric air is completely covered with a small layer of oxide. Analysis of the phase composition shows that the powder consists of magnesium without traces of oxide. Mass spectrometry with inductively coupled plasma shows a purity of the obtained particles of 99.99%. The characteristics of the porous structure are determined by low temperature porosimetry. The size of the obtained particles does not exceed 40 nm, and the average size is 23 nm. The used method of obtaining nanoparticles demonstrates high productivity (up to 50 g/h) and continuity of the process of obtaining nanoparticles (NP), the ability to control the size of the obtained nanoparticles (NP) in a wide range, noncontact heating, which leads to a high purity of the resulting product confirmed by mass spectrometry with inductively bound plasma. [ABSTRACT FROM AUTHOR]

Crystalline Zr‐fum‐MOF (MOF‐801) thin films of high quality are prepared on glass and silicon substrates by direct growth under solvothermal conditions. The synthesis is described in detail and the influence of different synthesis parameters such as temperature, precursor concentration, and the substrate type on the quality of the coatings is illustrated. Zr‐fum‐MOF thin films are characterized in terms of crystallinity, porosity, and homogeneity. Dense films of optical quality are obtained. The sorption behavior of the thin films is studied with various adsorptives. It can be easily monitored by measuring the transmission of the films in gas flows of different compositions. This simple transmission measurement at only one wavelength allows a very fast evaluation of the adsorption properties of thin films as compared to traditional sorption methods. The sorption behavior of the thin films is compared with the sorption properties of Zr‐fum‐MOF powder samples. [ABSTRACT FROM AUTHOR]

High-performance concrete is often heat-treated to increase early strength. Standardized temperature conditions for at least 24 h and sulphate-resistant cement thereby preventing delayed ettringite formation (DEF). In contrast, this paper investigates the risk of DEF for rapidly heat-treated HPC with a minimum temperature duration of 1 h to achieve a rapid early strength for stripping. In addition, a binder is used that does not exhibit increased sulphate resistance. For this purpose, standard prisms (L x W x H = 16 × 4× 4 [cm]) are heat-treated at 80 °C between 1 and 6 h without a pre-storage time. Samples with a temperature duration of 24 h serve as reference. First, the pore structure is analyzed using Mercury porosimetry to identify damage to the concrete matrix due to the rapid heat treatment. The investigation of DEF is achieved by two common approaches. The sulphate resistance is determined by means of wet-dry cycles on specimens for 90 days, whereby the changes in mass and strain as well as the cracking pattern on the concrete surface serves as a qualitative evaluation criterion. In addition, the SVA method on specimens directly after heat treatment, which determines the change in mechanical properties and the swelling behaviour of the concrete, leads to a quantitative evaluation of sulfate resistance. The measured pore distribution of the samples shows a significant increase of the capillary pores of up to 109% for decreasing temperature durations. However, the porosity does not affect the sulphate resistance of the concrete. The wet-dry cycles cause no damage due to DEF, since the change in mass and strains decreases with increasing cycles from up to 62.7% to − 2.5%. Furthermore, no visual differences were detected on the concrete surface between specimens with and without sulphate attack. As a result of the SVA test, maximum absolute strains of about 0.1 mm/m occur that are below the limit value of 0.152 mm/m. Also, the mechanical properties do not show a reduction in strength, but even an increase in tensile strength. In conclusion, the high-performance concrete formulation used in combination with rapid heat treatment investigated here did not result in detectable damage due to DEF.

This article aims to highlight the geotechnical, physical, mineralogical, and porosimetric characteristics and their variabilities along a clayey soil profile resulting from basalt under tropical conditions, which may influence soil parameters that are valuable in the development of geotechnical projects and construction control. The samples, obtained through Standard Penetration Test (SPT) drilling and excavation of a well, underwent geotechnical and physical characterization tests, X-ray diffraction (XRD) mineralogy analysis, and mercury intrusion porosimetry. In the uppermost part of the profile, the predominance of macropores generated by the micro-aggregated clay structure may explain the observed mechanical and hydraulic behavior and justify the values of geotechnical parameters, which may not always align with those expected for fine-grained soils. [ABSTRACT FROM AUTHOR]

Autogenous curing, also known as internal curing (IC), has revolutionised the way high-performance concrete (HPC) and high-strength concrete (HSC) are cured. IC improves the service life of concrete by lowering early-age cracking and enhancing durability. However, normal-strength concrete (NSC), the most commonly used type in the industry, is typically cured using conventional methods. Researchers are thus looking at ways to reproduce the positive results found in internally cured HSC/HPC in NSC. Studies have shown that IC is feasible in NSC despite its higher permeability, which results in loss of internal curing water (ICW). However, no comprehensive study has attempted to assess how the type, size and amount of IC agents affect the properties of NSC. The aim of this work was thus to optimise IC parameters for autonomous curing of NSC. The findings of this study support the notion that IC is possible in concrete with a high water/cement ratio and that, compared with lightweight aggregates (LWAs), superabsorbent polymers significantly impacted the durability properties of the NSC. Moreover, varying the size of the IC agent (LWA) had little effect on NSC properties, while increasing the amount of ICW considerably improved the durability properties. [ABSTRACT FROM AUTHOR]

This review focuses on disordered, or amorphous, porous heterogeneous catalysts, especially those in the forms of pellets and monoliths. It considers the structural characterisation and representation of the void space of these porous media. It discusses the latest developments in the determination of key void space descriptors, such as porosity, pore size, and tortuosity. In particular, it discusses the contributions that can be made by various imaging modalities in both direct and indirect characterisations and their limitations. The second part of the review considers the various types of representations of the void space of porous catalysts. It was found that these come in three main types, which are dependent on the level of idealisation of the representation and the final purpose of the model. It was found that the limitations on the resolution and field of view for direct imaging methods mean that hybrid methods, combined with indirect porosimetry methods that can bridge the many length scales of structural heterogeneity and provide more statistically representative parameters, deliver the best basis for model construction for understanding mass transport in highly heterogeneous media. [ABSTRACT FROM AUTHOR]

The structural characteristics of catalytic systems obtained by modification of activated carbon with Al and Ni metal oxides were studied. The activated carbon was modified by impregnation with metal hydroxides from solutions of salts with Ni+2/Al+3 ratios of 2:1 and 3:1 followed by calcination in a stream of nitrogen and hydrogen until oxide phases were formed. With increase in the ratio of metal cations in the impregnating solution in activated carbon the specific surface area and the number of micropores increase while the total volume and average diameter of the pores decrease. Calcination in a stream of hydrogen at the concluding stage of modification of the activated carbon leads to decrease of the pore space and decrease of the specific surface area of the catalytic system. The Ni/Al (2:1) catalytic systems obtained in nitrogen and hydrogen have the optimum combination of specific surface values and maximum average pore diameters for the treatment of heavy oil residue. [ABSTRACT FROM AUTHOR]

Foamed cements are coarse dispersions of a base cement slurry, a gas (usually air or nitrogen), a foaming surfactant and other materials A new foamed cement, designed for oil/gas well liners and casing cementing jobs, was formulated. Ultra-lightweight cement pastes (such as foamed cements) are appropriate for formation damage prevention in fractured and depleted reservoirs. In this work, foamed cements were prepared at high shear rates using a foaming agent primarily composed of sodium lauryl ether sulfate, boric acid and a retarder (JR120). This formulation was called FBJ. The samples were subjected to tests for density, rheology, free water, settling, thickening time, compressive strength (CS), fluid loss, porosity and permeability, along with microscopic photography and computed tomography scanning. Compared with other drilling cements, the FBJ was found to have one of the lowest densities (1200 kg/m3), a CS of 8963 kPa and a thickening time of about 3 h. The rheology of the FBJ improved under high-pressure and high-temperature conditions. Examinations of the set FBJ also showed that the pores were not interconnected, the porosity of the FBJ was greater than 73% and 28% of the FBJ was matrix. Moreover, cement permeameter tests indicated that the permeability of the FBJ was just 0.0109 mD (1 mD ≈ 1 × 10−12 cm2). All of these results show that the formulated FBJ has acceptable properties for oil/gas wells cementing applications. [ABSTRACT FROM AUTHOR]

In 2008, a late-12th-century merchant ship was discovered off the commercial port of Rhodes. The vessel caught fire before sinking and thus numerous hull timbers were found charred. Three main degrees of charring have been recorded that presented major chemical differences which indicated different conservation requirements. This study investigated the correlation between the chemistry of the waterlogged timbers and their physico-mechanical properties, to assist in the development of an appropriate conservation strategy. Scanning electron microscopy documented the morphology of charred, semi-charred and uncharred samples. Moisture content and density were measured gravimetrically, while porosity was evaluated using mercury intrusion porosimetry. Hardness was assessed using a modified Janka test and a penetrometer. The results obtained showed that differences in chemistry were highly correlated to the physico-mechanical properties of the timbers. The charred wood presented the lowest moisture content, shrinkage and porosity among the three charring conditions and it also had the highest density, Janka hardness and resistance to penetration. The exact reverse properties were recorded for the uncharred material, which was typical of badly preserved, waterlogged wood. The semi-charred wood presented transitional features. These results indicate that the uncharred wood is in need of consolidation, in contrast to the charred and semi-charred material, which may be left to air-dry untreated. [ABSTRACT FROM AUTHOR]

A 2D-NLDFT-HS study is performed of the effect the state of oxidation of the graphite matrix has on the parameters of micro-, meso-, and macropore structures of thermally expanded graphite (TEG). A wide range of the stage numbers of graphite intercalation compounds synthesized from natural flake graphite of the same grade is considered, along with the intercalant that is used and the particle size of the original graphite. The 2D-NLDFT-HS model provides a more accurate description of low-temperature nitrogen adsorption/desorption isotherms than other means. [ABSTRACT FROM AUTHOR]

In this study, the possibility of using mixing water containing O2 and O3 micro-nano bubbles (M-NBs) in concrete technology was investigated. In particular, the effect of micro-nano bubbles on the durability and frost resistance of concrete was analyzed. Concretes with two types of micro-nano bubbles were studied. The physical properties of both the modified concretes and the reference concrete were determined, i.e., specific and apparent density, porosity, weight absorption and coefficient of water absorption. Mechanical parameters based on compressive and flexural strength were tested after 14 and 28 days of curing. Concrete durability was determined on the basis of frost resistance and resistance to salt crystallization. The pore distribution in the cement matrix was determined based on porosimetry studies. The use of water with micro-nano bubbles of O2 and O3, among others, contributed to a reduction in the water absorption coefficient from 42.7% to 52.3%, in comparison to the reference concrete. The strength characterizing the concrete with O3 increased by 61% after 28 days, and the frost resistance after 150 F-T cycles increased by 2.4 times. Resistance to salt crystallization improved by 11% when water with O3 was used. [ABSTRACT FROM AUTHOR]

The Transcarpathian Basin, consisting of the Prešov and Trebišov sub-basins, is situated at the border of the Western and Eastern Carpathians. Hydrocarbon exploration in this basin has been ongoing for more than 60 years and reserves of economic importance are located in the E to NE part of the basin. The Trebišov sub-basin was analysed to characterize and predict lower Badenian (Langhian) reservoir rocks. To achieve this aim, new sedimentary facies, seismic facies, petrographic and paleontological analyses were performed, combined with original total porosity and permeability measurements. Based on the planktic foraminifera and calcareous nannoplankton zonation, the lower Badenian sequence in the Trebišov sub-basin was divided into a lower and an upper interval. The presence of very well sorted sandstone layers, glauconite grains, albitization, selective alteration of tuffs into zeolites as well as the fossil assemblages reinforce the volcanic influenced marine environments. Documented sedimentary structures indicate subaqueous density flows preceded by the newly observed fluvial and deltaic facies. The total sandstone porosity measurements indicate a gradual porosity decrease with depth marked by a value of 13.21 % at the surface decreasing down to 6.41 % at ~3 km below the surface. These numbers correspond to reservoirs with low to reduced porosity. Diagenetic products such as illite, chlorite and feldspar cement together with compaction effects, and variations in the crystallinity in siliceous cement led to the modification of initial porosity. The potential lower Badenian reservoir sandstones are frequently deformed by strike-slip faults responsible for the large pull-apart basin complex (seen as horsetail structures on reflection seismic sections) forming various fault-bounded structural traps. The lower Badenian sandstones present at the top of two anticlinal structures in the central part of the basin, display very strong reflection amplitudes on newly merged 3D reflection seismic data underlining the additional exploration potential in the basin. [ABSTRACT FROM AUTHOR]

The relevance of the research is caused by the need to reduce well drilling time on the Arctic shelf due to the limited navigation season and increased accuracy in assessing reserves obtained from the results of testing exploratory wells at the Dolginskoe field. The research results make it possible to select the optimal technology for drilling carbonate reservoirs of the Dolginskoe field, as well as to ensure the stability of the wellbore and preserve reservoir properties, establish the relationship between reservoir properties of rocks and stresses in productive formations, and justify the technological parameters of field development. The purpose of the research is to assess the influence of the composition, structure, filtration-capacitive properties of reservoir rocks and acting stresses on their permeability. Objects. Carbonate reservoir rocks of the Lower Permian and Carboniferous age were drilled in a well from a depth of 2982 m to a bottomhole of 3175 m and are characterized by pelitomorphic limestones, organogenic-detrital and cryptocrystalline varieties. Methods. The research was carried out by modern laboratory methods, including mercury porosimetry, the method of nuclear magnetic resonance, as well as a unique test bench of the Institute for Problems in Mechanics of the Russian Academy of Sciences. Results. On the basis of quantitative data of lithological and petrophysical properties, the authors have studied the deformation and strength characteristics of rocks from the probably productive part of the section of the Severo-Dolginskaya no. 1 well, which was not tested due to the short season of offshore operations. The data were obtained on the structure of the pore space, acoustic properties, density, porosity and permeability (including in reservoir conditions), residual water saturation, etc. The deformations of samples of rocks of a carbonate deposit in three directions and their relationship with permeability under stress conditions were studied. The new information obtained as a result of the work makes it possible to more accurately select the properties and component composition of the drilling fluid in order to control the repression, the formation of a thin impermeable filter cake, and to minimize the physicochemical interactions between the mud filtrate and formation fluids.

In many research areas, particularly in materials science, retrieving a 3D distribution of the material density in a sample is of key interest. Although standard lab-based X-ray μCT imaging is capable of retrieving the 3D distribution of local attenuation coefficients, the local density cannot be determined unambiguously without the use of calibration standards due to the polychromaticity of the used X-ray tubes. In this paper, two methods are presented to retrieve this information based on accurate knowledge of the polychromatic properties of source and detector in the used μCT system. The methods use a very different approach, one being a polychromatic pre-processing method and one relying on a novel polychromatic iterative reconstruction method, yet produce equivalent results. They are limited to objects with a homogeneous composition, but are extremely powerful in a broad range of applications in materials characterization where the density distribution is of interest. Moreover, the method relying on iterative reconstruction has the potential to be applied for multi-material objects as well. A number of application examples illustrate the potential of the methods to not only retrieve quantitative estimates of density and sub-voxel porosity, but also to greatly reduce or eliminate the spectral artifacts that often hinder conventional calibration schemes. • Two methods for quantitative reconstruction of polychromatic μCT data are presented. • The material density is directly retrieved for mono-material objects. • Using the proposed methodologies, no material-dependent calibration is required. • The methods improve the reconstruction quality for highly-attenuating materials. • One of the methods offers potential for multi-material objects. [ABSTRACT FROM AUTHOR]

Objectives. This study aims to establish the available porosity of a sorbent based on carbonized rice husk and investigate its sorption properties for oil and oil products.Methods. A rice-husk-based sorbent carbonized at 400°С for 30 min was selected as the subject. The porosity of this sorbent is analyzed with the help of mercury porosimeters, the Pascal 140 EVO and Pascal 240 EVO. The sorption properties of the sorbent are also studied when cleaning water containing oil and oil products.Results. The test sample is a bulk porous material with a pore volume of 0.015 cm/g; porosity higher than 15% was found, and the pore size distribution is shown. Studies were conducted on the sorption of oil and oil products as well as the possibility of using the aforementioned sorbent as a filtering material in the purification of water containing oil products. We investigated the sorption processes under dynamic and static conditions. The methodology for measuring the porous structure of solid materials on the mercury porosimeter, Pascal 140 EVO, was examined. The texture characteristics of the sorbent’s porous structure were determined, which is primarily the total volume of pores, the values of the specific surface area, and the volume of the microspores and mesopores.Conclusions. The materials studied can be used as sorbents with a developed porous structure for purification of water with dissolved and emulsified petroleum products.

It has been shown recently that coherent anti‐Stokes Raman scattering (CARS) allows probing the adsorption in optically transparent bulk nanoporous materials. The phases appearing in the pores at different conditions are identified by their resonant spectral contributions characterized by special values of the Raman shift and the linewidth. The present work demonstrates that the spectral amplitudes retrieved from the CARS spectra are the key for numerical description of the specific loadings of the phases. As a result, the adsorption isotherms can be obtained from the spectroscopic data. An essential point here is the presence of the nonresonant background caused by the material of the nanoporous matrix. It is used as the reference to overcome changes in collimated transparency of the sample in the pressure range at which the condensation occurs in the pores. Also, we show that the average pore radius can be estimated by analysis of a single CARS spectrum, allowing for the CARS‐porosimetry. [ABSTRACT FROM AUTHOR]

Blast-furnace slag (BFS) has been increasingly used in cement production and has shown great influence on the electrical resistivity of concrete. The objective of this paper is to compare the theoretical values of electrical resistivity obtained through a mathematical model with experimental values for concrete with BFS. Reference concrete mixtures with ordinary portland cement were also studied. Results indicate higher electrical resistivity and smaller porosity for concretes with CEM III/A. The electrical resistivity of the CEM III/A concrete does not have a well-defined correlation with the water-binder ratio (w/b) or with the compressive strength, unlike CEM I concretes. The correlation between calculated and experimental resistivity requires a correction factor for the CEM III/A concretes. In this study, the correction factor was obtained empirically by reducing the theoretical tortuosity of concrete by 15%. Therefore, the model should be used in cements with BFS with the application of a correction factor. [ABSTRACT FROM AUTHOR]

Small communities in remote areas of the United States often lack adequate water treatment services. Adsorption by granular activated carbon (GAC) is a vital drinking-water purification approach in small water treatment plants and point-of-entry and point-of-use systems. This study shows that rural communities can utilize a simple approach, thermal air oxidation (TAO), to produce their own GAC from locally available biomass materials. Unlike commercial GAC production processes that require high temperatures and activating gasses, activation of charcoals (biochars) by TAO can be achieved at moderate temperatures of 400‒500 °C without a regulated supply of activating gasses. After a brief TAO for 30‒40 min, charcoals/biochars showed significant increases in the surface area by up to 80-fold, oxygen-containing functional groups, porosity, and adsorption of test organic contaminants, including one anionic herbicide, two neutral triazine herbicides, and one natural estrogen. The GAC produced by the TAO process had a N2 B.E.T. surface area of up to approximately 850 m2/g, which is comparable to that of commercial GAC. The pore size distribution (PSD) of TAO-generated GAC was narrow and peaked at an approximate pore width of 0.8‒0.9 nm. Both the surface area and PSD were significantly affected by the conditions of TAO. GAC made from walnut/almond charcoals exhibited the highest adsorptivity, despite a relatively low surface area. This simple, innovative GAC production approach is suitable for use in small community- and household-scale applications, and therefore may benefit rural communities, water treatment professionals, farmers, and the GAC industry as a whole.

This paper shows the possibility that the mineral coal existing in the mining basins of northern Spain have a high added value. This would facilitate its future use in different fields such as new materials, nanotechnology, energy use in situ, coal bed methane, enhanced coal bed methane and coalmine methane. An analytical study of mineral coal samples is carried out. The samples come from two deposits located in coal basins of the Cantabrian Mountains. The duly prepared samples are subjected to an activation process. Within this transformation, different treatments are applied to different sub-samples. Some of the sub-samples suffer a previous demineralization by successive attacks with acids, followed by oxidation and pyrolysis. Finally, all of them are activated with CO2 and H2O(steam). The carbonaceous products resulting from each treatment are characterised. The results show that all the pre-treatments used were positive for the textural development of the materials. Likewise, proper management of the processes and of the different operating variables allows the procurement of carbonaceous materials with a "tailor-made" structural development of the coal type. This material receives the name "activated" and can be employed in specific processes. [ABSTRACT FROM AUTHOR]

Determining the characteristics of pore-throat structures, including the space types present and the pore size distribution, is important for the evaluation of reservoir quality in tight sandstones. In this study, the results of various testing methods, including scanning electron microscopy (SEM), pressure-controlled porosimetry (PCP) and rate-controlled porosimetry (RCP), were compared and integrated to characterize the pore size distribution and the effects of diagenesis upon it in tight sandstones from the Ordos Basin, China. The results showed that reservoir spaces in tight sandstones can be classified into those with three types of origins (compaction, dissolution, and clay-related) and that the sizes and shapes of pore space differ depending on origin. Considering the data obtained by mercury injection porosimetry and the overestimation of pore radii by pressure-controlled porosimetry, the full-range pore size distribution of tight sandstones can be determined by combining data from PCP with corrected RCP data. The pore-throat radii in tight sandstone vary from 36 nm to 200 µm, and the distribution curve is characterized by three peaks. The right peak remains similar across the sample set and corresponds to residual intergranular pores and dissolution pores. The middle and left peaks show variation between samples due to the heterogeneity and complexity of nano-scale throat bodies. The average micro-scale pore content is 33.49%, and nano-scale throats make up 66.54%. The nano-scale throat spaces thus dominate the reservoir space of the tight sandstones. Compaction, dissolution, carbonate cementation and clay cementation have various effects on pore-throats. Compaction and carbonate cementation decrease the pore body content, pore-bridging clay cementation decreases the throat space content, and Simultaneously, pore-lining clay cementation preserves pore space. [ABSTRACT FROM AUTHOR]

• Introducing an instrument for PALS with in-situ control of atmosphere, p and T. • Stable operation at 14 MPa argon atmosphere and 200 °C could be demonstrated. • Initial test measurements on polystyrene under 4 MPa argon pressure. We introduce a newly developed instrument for 22Na-based positron-annihilation lifetime spectroscopy (PALS) with in-situ temperature, pressure and atmosphere control. The system is designed for PALS measurements of samples in changing atmospheric conditions, from vacuum (∼10−5 mbar) up to a gas pressure of 20 MPa. Furthermore, we can select the composition of the applied gas, such as N 2 , Ar, Ar/H 2 , CO 2 as well as CH 4 and adjust the sample temperature from room temperature to 200 °C. To test the measurement principle, we carried out PALS measurements on semi-crystalline polystyrene in (99.999 %) pure argon atmosphere varying the pressure and the temperature simultaneously, up to 4 MPa and T = 150 °C. Changing the sample environment in that way affects the free-volume of the polymer, which is reflected in the positron lifetime and intensity. [ABSTRACT FROM AUTHOR]

Abstract We propose a porosimetry-based method to characterize pores formed by carbon nanotubes (CNTs) in the CNT agglomerates for designing neat CNT-based materials and composites. CNT agglomerates contain pores between individual CNTs and/or CNT bundles (micropore 50 nm). We investigated these pores structured by CNTs with different diameters and number of walls, clarifying the broader size distribution and the larger volume with increased diameters and number of walls. Further, we demonstrated that CNT agglomerate structures with different bulk density were distinguished depending on the pore sizes. Our method also revealed that CNT dispersibility in solvent correlated with the pore sizes of CNT agglomerates. By making use of these knowledge on tailorable pores for CNT agglomerates, we successfully found the correlation between electrical conductivity for CNT rubber composites and pore sizes of CNT agglomerates. Therefore, our method can distinguish diverse CNT agglomerate structures and guide pore sizes of CNT agglomerates to give high electrical conductivity of CNT rubber composites.

The accelerated test of mortar bars (AMBT) Is the fastest to detect the reactivity of aggregates. However, it presents several limitations regarding the classification, limits and the conditions to accelerate the test. When AMBT is used to classify mineral additions that potentially inhibit RAS, NaOH solution and high temperature are crucial factors. The present work aims to investigate the effect of AMBT on the development of RAS in combinations of cement with rice husk ash and silica fume. The induced expansion was used to assess the kinetics of RAS. In addition, the chemical and physical properties of the hydrated matrix under normal conditions of temperature and humidity and under test conditions were characterized by XRD, TGA and MIP. The fineness and particle size of rice husk ash were determinant in the mitigation of RAS. AMBT conditions are too aggressive to discard a material just by the determination of expansion. The mechanisms of action of mineral additions subjected to RAS must be better understood and evaluated by using tests that do not compromise their development. [ABSTRACT FROM AUTHOR]

With X-ray computed tomography still being flawed as a result of limitations in terms of spatial resolution and cost, toxic mercury intrusion porosimetry (MIP) is nowadays the prevailing technique to determine PSDs of most porous media. Recently, yield stress fluids porosimetry method (YSM) has been identified as a promising clean alternative to MIP. This technique is based on the particular percolation patterns followed by yield stress fluids, which only flow through certain pores when injected at a given pressure gradient. In previous works, YSM was used to characterize natural and synthetic porous media, and the results were compared with MIP showing reasonable agreement. However, considerable uncertainty still remains regarding the characterized pore dimension with each method arising from the highly complex geometry of the interstices in real porous media. Therefore, a critical stage for the validation of YSM consists in achieving successful characterization of model porous media with well-known pore morphology and topology. With this objective in mind, a set of four packs of glass beads each with a given monodisperse bead size were characterized in the present work using different porosimetry methods: experimental YSM, numerically simulation of MIP and pore-network extraction from a 3D image. The results provided by these techniques were compared, allowing the identification of the pore dimensions being characterized in each case. The results of this research elucidate the causes of the discrepancies between the considered porosimetry methods and demonstrate the usefulness of the PSD provided by YSM when predicting flow in porous media. [ABSTRACT FROM AUTHOR]

Porosity of eight samples of natural coals was measured in which, with increasing degree of metamorphism, the content of carbon in the organic mass grows from 80 to 93%, and that of oxygen decreases from 14 to 2%. The methods of low-temperature sorption of nitrogen and mercury porosimetry were used, and the isotherm of water sorption was examined (+27°C). Each method was used to calculate the pore volume and the monolayer capacity in sorption of water and sorption of nitrogen, and the pore surface area. The Dent sorption equation was used to calculate the amounts of firmly and weakly bound water in each sample. It was shown that that the amount of strongly bound water monotonically depends on the amount of oxygen in the organic mass. For the natural coal samples under study, the volume of sorbed water is close to the total pore volume determined by the method of mercury porosimetry and is an order of magnitude larger than the pore volume measured by the method of low-temperature nitrogen sorption. Reasons for this discrepancy are discussed. [ABSTRACT FROM AUTHOR]

A porosimetry technique that uses infrared-spectroscopic quantification of adsorbed probe molecules has been developed to characterize porous thin films. The amount of adsorbed probe molecules as a function of relative pressure of vapor is quantified via the absorbance of a characteristic signal of the probe molecule, to obtain adsorption isotherms. The pore size distributions of nanoporous thin films of SiO 2 -ZrO 2 , TiO 2 , and mesoporous silica MCM-41 are determined based on the Kelvin equation. In this technique, water and hexane are used as condensable vapors. Pore size distribution curves measured by infrared-spectroscopic porosimetry are in good agreement with those measured by the conventional gas/vapor adsorption technique, although the surface area per sample was less than 1 square meter. The results verify that the infrared-spectroscopic porosimetry technique is a simple methodology for characterizing the porous structures of thin films. • Porosimetry technique for characterizing micro- and mesoporous thin films. • The amount of adsorbed probe molecules is quantified by infrared spectroscopy. • Pore size distributions of thin films with thickness less than 1 μm are determined. • IR-porosimetry is compared with conventional porosimetry techniques. [ABSTRACT FROM AUTHOR]

In post-fire investigation, the damage of fire-exposed concrete is usually related to the temperature time-history. This paper presents the results of an experimental investigation on reinforced concrete, cement pastes and mortars exposed to fire, aimed at identifying the benchmarks necessary to reconstruct the thermal path 15 dry core samples were obtained from a real fire damaged structure and compared to other reference dry cores collected in not damaged zones of the same structure. In addition, 16 irregular spalling samples were collected and investigated. In order to assess changes in mineralogical composition and microstructure modifications due to temperature, 20 cubic cement pastes samples and 20 prismatic mortars specimens were realized and exposed to temperature ranging from 200 ∘ C up to 800 ∘ C with a gradient of 10 ∘ C /min and keeping the maximum temperature for 1 h. Optical and Scanning Electron Microscopy, X-Ray Diffraction, Thermoanalysis and MIP porosimetry along with Helium picnometry allowed to investigate the damage degree and the mineralogical changes of the concrete and other cement based materials. Calibrated Colorimetry could determine fire temperature in the different parts of the samples due to colour changes in the mineralogical phases and in the microstructure of cement materials. The absence or presence of some specific minerals (like Portlandite), the colorimetric variations and other microstructural features are markers capable of assessing the temperature reached with high accuracy. The approach and the data showcased in this work can be useful for post-fire investigations, for theoretical and numerical models tuning and to optimize the structural retrofitting. [ABSTRACT FROM AUTHOR]

In this study, we performed a multi-scale characterization of precipitated silica including small-angle X-ray scattering (SAXS), analytical (ultra-) centrifugation as well as electron microscopy and pore size determination techniques. Information about the primary particles and their size distribution within the aggregate, the aggregate size and its fractal dimension, as well as mesoscopic bulk properties, e.g. porosity and sediment structure analysis, were put into context. The data obtained here allow a statement to be made about the number of primary particles per aggregate and the aggregate structure including pore size distribution and pore inlet diameter. The correlation of the obtained measurement data with mathematical models allows a deeper understanding of the structure and description of fractal aggregates. Unlabelled Image • Multi-scale characterization of precipitated silica using SAXS, AUC and REM. • Analysis of aggregate structure using pore size determination techniques. • Determination of fractal dimensions, sediment structure as well as porosity. • Correlation of the measurement data with mathematical models. [ABSTRACT FROM AUTHOR]

Abstract The objective of the present study is to develop a biotechnological tool for a new application of clay phyllites as stabilized materials in linear works replacing chemical stabilizer (e.g. cement or lime) by natural cement, formed by precipitated calcium carbonate generated by microorganisms of the Bacillaceae family (Bacillus pasteurii). Part of the development process conducting a chemical and mineralogical characterization and an examination of physical and hydromechanical properties. The results of this study show that the effect of bacteria on clay phyllites increases the calcium carbonate content, specific surface area and plasticity values. These increased values are caused by the addition of a non-plastic component to clay phyllites resulting in a more aggregated structure through the precipitation of calcium carbonate from the bacteria, ultimately filling the pores of this material. Microbiological treatments on clay phyllites tends to aggregate the original particles, creating aggregates that are partially associated with the formation of calcium carbonate. Said process is influenced by the curing and compaction procedures conducted on samples, which also cause breakage of carbonated structures formed during treatment. As a result of this breaking process of aggregates, some compaction energy is lost and the treated samples do not reach the maximum dry density of the natural state for the same level of compaction energy applied. Treated samples display a slightly larger friction angle with no cohesion, consistent with filling properties and denser condition. Compressibility is consistently lower than that of the natural state. Comparison of collapse data shows that the occurrence and amount of collapse are controlled by the as-compacted dry density. It is also determined that higher compaction effort is even more effective than increasing the amount of bacteria introduced to stabilize the sample for the filling of pores (size ranges 3–50 μm) with calcium carbonate. However, the post-ageing compaction destroys the initial binding/cementation effect. Highlights • Clay phyllites are investigated in biotechnological solutions using microorganisms. • Precipitation of carbonate from bacteria takes place in the pores of phyllite clays. • Mechanical properties of samples are improved using the microbiological technique. • Treated samples display a slightly larger friction angle with no cohesion. • Aggregates are formed in treated clay phyllites due to the bioprecipitated carbonate. [ABSTRACT FROM AUTHOR]

Highlights • Cation distribution was determined in 10-nm sized Mn 0.6 Zn 0.4 Fe 2 O 4 particles. • Small clusters of Mn-Zn ferrite crystallites were coated with mesoporous silica. • The mesoporous shell was loaded with rhodamine B as a hydrophilic model compound. • The shell was sealed by a temperature-sensitive gatekeeper to control the release. Abstract Hydrothermal synthesis was employed to prepare three samples of Mn-Zn ferrite nanoparticles with the mean size of crystallites of 12–14 nm, whose compositions were accurately determined by X-ray fluorescence spectroscopy to Mn 0.82 Zn 0.21 Fe 1.97 O, Mn 0.70 Zn 0.31 Fe 1.99 O 4 , and Mn 0.62 Zn 0.41 Fe 1.97 O 4. The X-ray diffraction and SQUID magnetometry were used to determine the spinel structure and ferrimagnetic properties of the samples. AC field heating experiments were performed on particles dispersed in glycerol to evaluate the specific absorption rate. Based on the superparamagnetic behaviour and magnetic hyperthermia data, the Mn 0.62 Zn 0.41 Fe 1.97 O 4 phase was selected for further studies, including a more detailed characterization of the crystal and magnetic structure by neutron diffraction and Mössbauer spectroscopy, encapsulation into mesoporous silica, determination of the specific absorption rate of coated particles, and analysis of the porosity of the shell. Shortly, the Mn 0.62 Zn 0.41 Fe 1.97 O 4 nanoparticles were found to possess high magnetization of M (10kOe) = 48.4 emu/g at room temperature and superparamagnetic behaviour at body temperature on the timescale of magnetic measurements. The coated product was formed by clusters of ferrite crystallites with overall mean size of 52 nm encapsulated into 22 nm thick mesoporous shell and showed heating efficiency of 57 W/g(Mn + Fe) in AC field of 970 kHz and amplitude of 8 mT. The mesoporous shell provided specific surface area of 670 m2/g, and its pores of an average diameter 3 nm occupied specific volume of 0.45 cm3/g. In a a preliminary study, the silica pores were loaded with rhodamine B as a model of a hydrophilic drug and subsequently enclosed by lauric acid that served as a temperature sensitive gatekeeper. The release of the model compound to aqueous medium was determined at room temperature and 60 °C by spectrophotometric analysis. Results have shown that amount of rhodamine B in pores achieved 15 mg per gram of silica-coated ferrite cores and its release was controlled by temperature. [ABSTRACT FROM AUTHOR]