Mercury Porosimetry Research Articles

A rapid method for on-line solid-phase extraction and determination of dioscin in human plasma using a homemade monolithic sorbent combined with high-performance liquid chromatography.

A phenyl-based polymer monolithic column was prepared via free radical polymerization in a stainless steel column with the size of 4.6 mm i.d. × 50 mm, using ethylene glycol phenyl ether acrylate as the monomer. The resulting monolithic column shows high porosity of 73.42% and relative uniform pore structure, as characterized by mercury porosimetry and scanning electron microscopy, respectively. The optimized polymer monolith column was used for on-line solid-phase extraction prior to the reversed phase mode HPLC-UV analysis for the determination of dioscin in human plasma, using a COSMOSIL C18 column (4.6 mm × 150 mm, 4.5 μm). Water was used to wash non-retained components from the SPE sorbent, and methanol water (80:20, V/V) was used as the mobile phase for isocratic elution of dioscin. The maximum adsorbed quantity of dioscin to the SPE column is 6.79 mg/g, which is high enough for the quantitative analysis of dioscin in plasma, due to the low content of dioscin in plasma. The method was validated by assessing the linearity, lower limit of quantification, intra- and inter-day precision, accuracy, and repeatability. The developed method was applied for the analysis of dioscin in plasma from a volunteer who had orally administered an aqueous extract of dioscorea nipponica rhizome, showing the method capable of detecting dioscin in the plasma. These results show that the developed method is a rapid method for on-line solid-phase extraction and determination of dioscin from plasma, exhibiting good selectivity with hydrogen bond interaction and hydrophobic interaction, good clean-up ability, cost-saving, and time-saving. Graphical abstract.

Shale gas potential of the Prince Albert Formation: A preliminary study

Abstract Recent investigations of the shale gas potential in the main Karoo Basin have concentrated on the Whitehill Formation within the Ecca Group. This study focuses on the shale gas potential of the underlying Prince Albert Formation using the parameters of volume porosity, permeability, total organic carbon (TOC), vitrinite reflectance and Rock-Eval data. Shale samples were retrieved from three surface localities in the southern part of the main Karoo Basin and from core of three boreholes drilled through the Prince Albert Formation near Ceres, Mervewille and Willowvale. The sampling localities occur near the borders of the prospective shale gas areas (“sweet spots”) identified for the Whitehill Formation. Kerogen was found to be Type IV with hydrogen indices less than 65 mg/g. Shale porosities are between 0.08 and 5.6% and permeabilities between 0 and 2.79 micro-Darcy, as determined by mercury porosimetry. TOC varies between 0.2 and 4.9 weight % and vitrinite reflectance values range from 3.8 to 4.9%. Although the porosity and TOC values of the Prince Albert Formation shales are comparable with, but at the lower limits of, those of the gas-producing Marcellus shale in the United States (porosities between 1 and 6% and TOC between 1 and 10 weight %), the high vitrinite reflectance values indicate that the shales are overmature with questionable potential for generating dry gas. This overmaturity is probably a result of an excess depth of burial, tectonic effects of the Cape Orogeny and dolerite intrusions. However, viable conditions for shale gas might exist within the “sweet spot” areas, which were defined for the Whitehill Formation.

Is it Possible to Create Readily Available Tissue-Engineered Vascular Grafts Without Using Cells?

Introduction - In modern vascular surgery remains the problem of small-diameter vascular grafts. Autologous or synthetic vascular grafts are used routinely for arterial bypass in patients with cardiovascular disease. However, some patients either lack suitable autologous tissue or cannot receive synthetic grafts. Such patients could benefit from a vascular graft produced by tissue engineering. Currently, there are a number of techniques to receipt such artificial vessel, some of which are already in clinical trials. The method of using acellular biodegradable scaffold suggests that host cells can regenerate new vascular wall in situ, thats allows to overcome the scalability issue and make the grafts available off-the-shelf. The aim of the study is a comprehensive assessment of bioresorbable prosthesis from L-polylactide (PLA), and determining the possibility of its use as acellular vascular graft available off-the-shelf. Methods - Tubular grafts were obtained by the electrospinning method, (1.2 mm inner diameter) on the basis of nonwoven nano- and microfiber biodegradable polymer PLA. Mechanical characteristics such as tensile strength ,Young’s modulus E, and tensile deformation at break ofthe samples were determined using a UTS 10 universaltesting machine (Germany). Porosity parameters were determined by mercury porosimetry and BET method. Cytology analyses were performed with nanofibersfrom PLA and culture of mesenchymal stem cellsobtained from adipose tissue (ASCs). To assess the degree of cell adhesion toPLA grafts investigated materials were placed insquare-hole board (Nunc, USA). Investigation of barrier propertiesof tubular grafts were carried out on a developed laboratory setup. Obtained grafts were implanted in the abdominal aorta of rats (n=18). Follow-up was 16 months. The material was subjected to histological examination, electron microscopy, immunohistochemistry CD 31 +. After 14 months implantation angiography was performed (n=1). Results - During the operations and by the results of the investigation physical and mechanical properties it has been shown that obtained grafts are suitable for sewing in the bloodstream. For grafts from L-polylactide the pore volume was 78% and the surface area per gram of polymer 3.6 m2 (S BET).Investigation of adhesion and proliferation of mesenchymal stem cells derived from adipose tissue of rats showed safety and biocompatibility of used materials. All grafts formed neointima, with no signs of hyperplasia in the areas of anastomoses. Patency for PLA grafts 88% (n = 18). After 16 months (n=3) histology shows total resorption of PLA fibers, new vascular wall consist of connecctive tissue with endotelial lining, but all zone of reconstruction was presented by aneurysm. Conclusion - Small diameter vascular prostheses with high porosity obtained by electrospinning from PLA have sufficient exploitation mechanical properties. In in vivo experiments proved its safety, biocompatibility. Received patency rates are satisfactory for grafts with small diameter. Low mechanical properties of the connective tissue formed in the area of reconstruction have led to the formation of aneurysms. To sum up, the need for the introduction of cells in the wall of the graft in vitro before implantation is not in doubt.

The correlation between porosity characteristics and the crystallographic texture in extruded stabilized aluminium titanate for diesel particulate filter applications

Porous ceramic diesel particulate filters (DPFs) are extruded products that possess macroscopic anisotropic mechanical and thermal properties. This anisotropy is caused by both morphological features (mostly the orientation of porosity) and crystallographic texture. We systematically studied those two aspects in two aluminum titanate ceramic materials of different porosity using mercury porosimetry, gas adsorption, electron microscopy, X-ray diffraction, and X-ray refraction radiography. We found that a lower porosity content implies a larger isotropy of both the crystal texture and the porosity orientation. We also found that, analogous to cordierite, crystallites do align with their axis of negative thermal expansion along the extrusion direction. However, unlike what found for cordierite, the aluminium titanate crystallite form is such that a more pronounced (0 0 2) texture along the extrusion direction implies porosity aligned perpendicular to it.

Nanoscale pore structure heterogeneity and its quantitative characterization in Chang7 lacustrine shale of the southeastern Ordos Basin, China

To gain a better understanding of nanoscale pore structure characteristics in Chang7 lacustrine shale, Ordos Basin, China, 33 shale samples from 15 wells are examined and analyzed by total organic carbon (TOC), X-ray diffraction (XRD), mercury porosimetry, helium pycnometry, low-pressure N2 adsorption experiments and fractal method. The results show that Chang7 lacustrine shale pores diameter is mainly from 1.5 to 5 nm, and mesopores give the largest contribution to the total pore specific surface area (SBET) and volume (VBJH), and micropores have the second contribution to SBET but little contribution to VBJH, macropores have very little contribution to SBET but make a good contribution to VBJH. According to the occurrence and origin of shale pores, micro-pores can be divided into mineral intragranular pore, minera intercrystalline pore and organic pore. Two fractal dimensions (D1 and D2) are obtained from N2 adsorption isotherms analysis using FHH method. Relationships between fractal dimensions and shale compositions, pore structure parameters are investigated, which show that both D1 and D2 have good positive relationships with SBET and VBJH, but obvious negative correlations with the average pore diameter. That is, the smaller the pore diameter, the more complex the pore structure is, resulting in the larger pore surface and volume. D1 and D2 are both positively correlated with total clay, illite, mixed-layer of illite-smectite, whereas no obvious relationships with chlorite, indicating that the layer and flocculent structure increase the complexity of nanoscale pore structure. TOC content has positive correlation with D1 but no obvious relationship with D2, indicating that the pores in organic matter are mostly micropores. Fractal dimensions are negatively correlated with total brittle mineral, quartz and feldspar content, that is because the surface of brittle minerals is smoother and more homogenous than that of clay minerals.

A novel multi-technique approach used in the petrophysical characterization of the Maquoketa Group (Ordovician) in the southeastern portion of the Illinois Basin: Implications for seal efficiency for the geologic sequestration of CO2

Quantifying the petrophysical properties of low-permeability sedimentary units helps to determine the possibility of upward flow of supercritical carbon dioxide when evaluating a site for safe confinement of geologic carbon storage. This research examines fine-scale pore characteristics that affect the sealing capacity of the Upper Ordovician Maquoketa interval, a thick and heterogeneous sequence of carbonates, siltstones, and clay-rich rock units in the Illinois Basin. This unit has been previously identified as a regional caprock that would likely isolate and effectively store any CO2 injected into underlying reservoirs. We applied a multi-technique approach to quantify pore-size distribution, pore surface area, porosity, permeability, and capillary entry pressure. These laboratory-based techniques include mercury porosimetry, gas adsorption, portable X-ray fluorescence, X-ray diffraction, total organic carbon analyses, and, to a lesser extent, scanning electron microscopy and petrography. In addition, we developed a lithofacies model that interpreted the combined wireline responses from multiple well locations. This model confirms that the Maquoketa Group is dominated by muddy limestone, dolomitic/calcitic shale, and silty shale. The results of these evaluations indicate that these sequences have low porosity (0.4–3.1 %) and low permeability (0.04–7.1 mD) values and capillary entry pressures adequate to inhibit invasion of supercritical CO2 driven by buoyancy forces. Laboratory results also indicate that portions of the Maquoketa Group may also function as a low-volume reservoir for CO2. That is, should supercritical CO2 migrate upward and percolate into this unit, most of the CO2 will likely be securely trapped by means of capillary mechanisms.

Study of pore morphology, microstructure, and cell adhesion behaviour in porous Ti-6Al-4V scaffolds

In the present work, dense Ti-6Al-4V sample and porous Ti-6Al-4V scaffolds were prepared using powder metallurgy route. Milled Ti-6Al-4V powder was blended with a space holder (ammonium bicarbonate), consolidated with and without binder (camphor) using uniaxial press and sintered at 1200 °C for 75 min in argon atmosphere. Space holder of different size fractions (− 250 + 212 and -300 + 250 μm) were obtained by sieving and used during blending. A maximum densification is achieved in the dense Ti-6Al-4V sample after sintering. The SEM micrograph of the dense Ti-6Al-4V sample confirms the presence of α- and β-phases. Porous Ti-6Al-4V scaffolds obtained after sintering show the density of about 60% theoretical. In all the porous scaffolds, the porosity of about 40% was achieved. This result is substantiated with the results from mercury porosimetry. Sinterability i.e. change in density from de-binding plus pre-sintering to sintering is observed to be the same in dense sample and porous scaffold prepared with a − 250 + 212 μm space holder. Micrographs of sintered porous scaffolds show presence of both macropores and micropores. Coalescence of macropores to form a large pore is also seen. An increase in the macropore size is observed when the sample is prepared with a certain space holder and binder. Also, a significant reduction of micropores within the solid networks is also seen in the binder-added samples. Finally, the cell attachment and viability studies using osteoblast-like MG63 on porous scaffolds show good cytocompatibility.

Adsorption of anionic and cationic dyes into shaped MCM-41

The adsorption of Basic Blue 41 (BB41), Methylene Blue (MB) and Basic Red 18 (BR18), three known basic dyes, was studied in shaped mesoporous adsorbent MCM-41. The granules were obtained by extrusion of the powder adsorbent and were analyzed by nitrogen adsorption, SEM–EDS, XRD, mercury porosimetry and helium picnometry. Adsorption equilibrium isotherms, kinetics, and breakthrough curves were performed with the selected adsorbent and dyes. The experimental results indicated that the Sips model better describes the equilibrium than the Langmuir and Freundlich isotherm models. Additionally, the co-adsorption equilibrium of two dyes was well predicted by the extended form of the Sips model. The kinetics results showed that the adsorption of Basic Blue 41 onto the selected adsorbent is faster than with the other studied dyes. The obtained adsorbed equilibrium amounts through the breakthrough curves were 308 mg g−1, 55 mg g−1 and 106 mg g−1 for the Basic Blue 41, Methylene Blue and Basic Red 18 dyes, respectively. The dye is concentrated during regeneration step, since the volume of regenerating solution, eluted during the regeneration, is considerably lower (about two orders of magnitude) when compared with the volume of effluent treated until the breakthrough point. This fact demonstrates the feasibility of a potential adsorption based process to treat dyed effluents, with the shaped MCM-41.

Fixed bed biosorption of silver and investigation of functional groups on acidified biosorbent from algae biomass.

This work investigated the use of acidified dealginated residue from Sargassum filipendula algae for biosorption of silver in fixed bed column. This biosorbent was esterified for carboxyl and sulfonate groups to investigate the influence of these groups on silver removal percentage. Potentiometric titration was also evaluated on acidified and esterified biosorbents. Porosity and specific weight were determined by helium picnometry and mercury porosimetry techniques. The results showed that carboxyl and sulfonate groups were significant on silver biosorption. Potentiometric titration showed that esterified and acidified biosorbents presented different acid groups. The porosity of the acidified biosorbent was around 40%. Fixed bed assays were conducted to evaluate the influence of inlet concentration and feed flow rate of silver. Higher percentage removal of silver was obtained at 1.0 mmol · L-1 and 0.5 mL · min-1. Modified dose-response model obtained the best prediction of experimental data among breakthrough curve models.

Sol–Gel Synthesis of Functionally Graded SiC–TiC Ceramic Material

Functionally graded SiC–TiC composite materials are promising for using in the aerospace industry as relatively low-density materials. The production of such materials by the sol–gel synthesis of a finely divided titanium carbide matrix in the pore space of SiC frameworks was studied. It was demonstrated that the distribution of the TiC matrix in the space of the SiC framework can be changed by varying the composition of the coordination sphere of precursors. It was shown that, after eight cycles of hydrolysis of titanium-containing precursors in the presence of a phenol formaldehyde resin with subsequent carbonization and carbothermal synthesis (1400°C, dynamic vacuum, 2 h), the weight gains of the samples differed significantly: for the precursor [Ti(OC4H9)2.05(O2C5H7)1.95], which is more sensitive to moisture, it was 23%, and for the complex [Ti(OC4H9)1.95(O2C5H7)2.05], it was 37%. Moreover, in the former case, near-surface regions of the material were predominantly densified. It was noted that, with increasing content of the modifying phase TiC, the compressive strength increased, and the specific surface area decreased (as determined by low-temperature nitrogen sorption and mercury porosimetry). The obtained gradient of the composition of the SiC–TiC ceramics across the depth was confirmed by X-ray computed microtomography: the total porosity of the near-surface regions of the ceramics differed by a factor of 2.9.

Reaction Kinetics of Vanillin Hydrodeoxygenation in Acidic and Nonacidic Environments Using Bimetallic PdRh/Al2O3Catalyst

The kinetics of hydrodeoxygenation (HDO) reaction in literature are mostly reported for single model compounds in bio-oil. However, these kinetic models may become invalid in the real bio-oil environment where other model compounds are present. This study investigates the effect of acetic acid, which is a major compound in bio-oil, on the liquid-phase HDO reaction kinetics of vanillin (VL). A synthesized bimetallic catalyst (PdRh/Al2O3) was utilized in a batch reactor at 308–328 K, 1–4 MPa H2 gas partial pressure (PH), 263–526 mM initial VL concentration (CVL0), and 1.9–4.6 kg/m3 catalyst loading with ethyl acetate as the reaction solvent. N2 adsorption–desorption, scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray fluorescence (XRF), CO chemisorption, and mercury porosimetry methods were used to determine the physicochemical properties of the catalyst. Transport limitations in the system were ruled out via the Madon–Boudart test, Weisz–Prater criterion, agitation, and particle size test. ...

Studying the Structure of Products Made of Titanium Carbide Hardened by the Impregnation Method

The paper presents the results of studying the structure of products made of titanium carbide hardened by the impregnation method. As a bonding alloy a high-temperature alloy of the Fe-Cr-Ni-Co system was used. Samples of different porosity were impregnated with that alloy, then their structure was investigated by the methods of mercury porosimetry and electron microscopy. The data of the parameters of porosity and some mechanical properties are given. It was found that there is a correlation between the average size of open pores and the tensile strength and the ultimate strength limit. It is shown that this relationship is logical if to consider the resulting structure as a composite material: the matrix of titanium carbide which pores are filled with a metal bond. It is shown at what parameters of the porous structure the impregnation process proceeds most fully.

Features of determining the parameters of the porous structure of ceramic materials

The methods for determining the pore volume distribution by the size of porous materials are analyzed and it is shown that the most rigorous are methods in which capillary effects do not appear. It is shown that mercury porosimetry and the method of liquid displacement by gas have a large error in the region of large pores. This is due to the percolation effect. It is proved that determining the distribution of pore volume from measurements of air flow gives too distorted results, so its use is not advisable.

The Role of Magnetic Susceptibility in Detecting Iron Poisoning in FCC Equilibrium Catalyst Samples and Its Combination with Other Macroscopic Bulk Analysis Techniques

In the last years, iron poisoning has gained more attention in fluid catalytic cracking operations across the globe. While more and more insights into the mechanisms of its deactivating effects on FCC catalyst particles are available, the early detection of Fe poisoning of FCC catalysts is complicated by the various sources of Fe. This paper describes the use of magnetic susceptibility determinations and digital microscopy for this purpose. The application of magnetic susceptibility shows that the magnetic properties of FCC catalysts change at about 0.30 wt % added Fe indicating that the deleterious effects of the contaminant Fe occur beyond this limit. The combination with inverse gas chromatography and mercury porosimetry determinations confirm the pore restricting effects by Fe poisoning.

The Effect of Hydration on Pores of Shale Oil Reservoirs in the Third Submember of the Triassic Chang 7 Member in Southern Ordos Basin

Shale oil is an unconventional kind of oil and gas resource with great potential. China has huge reserves of shale oil, and shale oil resources are abundant in the third submember of the Triassic Chang 7 member in the southern Ordos Basin. At present, this area is in the initial stage of shale oil exploration and development. The reservoir pore is one of the key factors affecting oil accumulation, drilling safety, and oil production. It is also an important reservoir parameter that must be defined in the exploration stage. In general, the clay content in the shale section is high, and is prone to hydration. In order to study the effect of fluid on the pore type, structure, and distribution of shale oil reservoirs, experiments using X-ray diffraction, a porosity–permeability test, mercury porosimetry, rock casting thin section, and scanning electron microscopy were carried out. The experimental results show that the content of clay and quartz is very high in the studied formation. The pore porosity and permeability of the rock is highly heterogeneous because of the obvious stratigraphic bedding and interbeds. Microstructural observation of rocks shows that the main pore types are intergranular pores, intragranular pores, intercrystalline pores, and organic pores. Crack types are dissolution cracks, contraction cracks of organic matter, and abnormal pressure structural cracks. After hydration, the porosity of rock will increase in varying degrees, and pore size, pore content in different sizes, and pore structure will also change. The results show that the pores of tuff mainly changes at the initial stage of hydration, and the pore change of tuff is the most obvious within 6 hours of soaking in clear water. The influence of hydration on the pore of shale is greater than that of tuff, but the main change stage is later than tuff, and the pore change of shale is the most obvious within 12 to 24 hours of soaking in clear water. The soaking experiment of water-based drilling fluid (WBM-SL) shows that it can plug a certain size of holes and cracks and form a protective layer on the rock surface, thus effectively reducing hydration. In actual construction, multisized solid particles should be allocated in drilling fluid according to the formation pore’s characteristics, and the stability of the protective layer should be guaranteed. This can reduce the accident of well leakage and collapse and is conducive to the efficient and safe development of shale oil.

Modeling and optimizing of anode-supported solid oxide fuel cells with gradient anode: Part I. Model description and validation by experiments

Grading the porous anode microstructure, i.e., gradient anode is an effective way to enhance the electrical performance of anode-supported solid oxide fuel cells (SOFCs). This article is the first part of a two-part article which presents a 3D numerical model of a gradient anode SOFC and conducts a model validation in comparison with the experiments for the gradient anode SOFC modeling and optimizing. An experimental test setup was constructed first to evaluate the electrical performance of a SOFC button cell with a gradient anode. Then the microstructure characterization of each cell component was obtained by combining the mercury porosimetry with image analysis. Parameters relating to the microstructure mainly included the layer thickness, porosity, pore size, and particle size. Based on the microstructure parameters and measured electrical performances, the numerical model of the gradient anode SOFC button cell was established, which related the cell microstructure to the electrochemical characteristics. The results show that the microstructure parameters of each cell component can be quantificationally obtained by the backscatter electron image analysis. The modeled i-V and i-P curves at three flow rates of fuel gas (75/100/125 mL·min−1) agree well with the experimental data. This validation process indicates that the numerical model is able to accurately describe the electrical performance of the gradient anode SOFC and it can be further extended to optimize the anode microstructure distribution.

Conductive shape‐memory polyurethane/multiwall carbon nanotube nanocomposite aerogels

ABSTRACTSmart nanocomposite aerogels have promising applications. In this work, different percentages of multiwall carbon nanotube (MWCNT) added into synthesized polyurethane (PU) gel in the molten state, using a two‐roll mill. By soaking the PU/MWCNT nanocomposite gel into the water, PU/MWCNT hydrogels containing more than 90 wt % of water were prepared. The obtained hydrogels were freeze‐dried to produce aerogel counterparts. The aerogels were fully characterized using mercury porosimetry, differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and field emission scanning electron microscopy (FE‐SEM). The electrical percolation threshold of conductive aerogel system was measured. The shape‐memory behavior of PU/MWCNT nanocomposite aerogels was evaluated by dynamic mechanical thermal analysis (DMTA). The results of the DMTA showed that by adding 2.75 wt % of MWCNT, the recovery ratio and storage modulus of the PU/MWCNT nanocomposite aerogel increased 42 and 180%, respectively. The electrical conductivity of the system also increased three orders of magnitude at the percolation threshold. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48602.

Microcrystalline Characterization and Morphological Structure of Tectonic Anthracite Using XRD, Liquid Nitrogen Adsorption, Mercury Porosimetry, and Micro-CT

Tectonic deformation acts as an indispensable factor affecting the crystalline structure, but its relationship with the evolution mechanism of the morphological structure is seldom considered. In this work, the characterization of microcrystalline and morphological structures in tectonic coal was comprehensively explored using X-ray diffraction (XRD), pore structure analyzers (liquid nitrogen and mercury intrusion methods), and micro-computed tomography (micro-CT). The XRD results indicate that a transformation of the chemical composition was observed in the coal body after continuous tectonic deformation. Meanwhile, the variation in microcrystalline parameters, such as the interlayer spacing (d), stacking height (L), effective stacking layer number (N), aromaticity (f), and graphitization degree (g), reveal that the microcrystalline structure of tectonic coal has experienced a positive evolution with graphitization and aromatization. Pore morphological analyses demonstrate that pore volume distributions of micropores, mesopores, and macropores were totally enhanced by tectonism while the pore shape potentially changes slightly. Simultaneously, the incremental noneffective pores of tectonic coal may promote gas accumulation and storage in the pore space. Fracture morphological analyses utilizing micro-CT lay emphasis on the orderly distributed cleats with a uniform scale in original coal, whereas the reconstruction of microstructures in tectonic coal illustrates a scattered distribution with good connectivity. In addition, the evolution of the macromolecular structure has an influence on the growth of nanoscale pores since the lattice defects may generate from the interlayer of the aromatic ring or the internal space. This research is of an enlightening significance for understanding the influence of tectonic stress on the chemical structure evolution of coals and its relationship with the nanoscale morphological structure development in tectonic coal.

Fabrication of porous boron nitride by using polyborazylene as precursor, polymethylmeth-acrylate as reaction agent

A novel process for the production of micro-molecular boron nitride foams has been developed through foaming of boron nitride preceramic polymer with the help of sacrificial microbeads of polymethylmethacrylate (PMMA), followed by pyrolysis under inert atmosphere. The process parameters of porous BN ceramics were studied by thermo gravimetric analysis, thermo mechanical analysis, X-ray diffraction, scanning electron microscopy, mercury porosimetry and elemental analysis. The microstructure and element composition of the porous ceramics were also studied by the above methods. The results showed that: when using polyborazylene from thermolization of borazine at 60°C as boron nitride precursor, PMMA microbeads with pore size of 25μm as sacrificial microbeads, adding into polyborazylene powder with 80 wt% in the foaming mixture. After warm-pressing the powders under 74MPa at 60°C, subsequently pyrolyzing the powders under ammonia to 1000°C then to 1450°C under nitrogen atmosphere, we can obtain boron nitride foams. Through scanning electron microscopy observation, X-ray diffraction analysis and porosity measurement, it was confirmed that the obtained boron nitride pieces were microcellular foams with homogeneous distributed pore size average at ∼19.15μm and had a mostly interconnected porosity of 79.06 vol%. The temperature should be increased to 1700-1800°C to prepare porous BN ceramic with a certain degree of crystallinity (layer spacing d002 = 0.335-0.333 nm)

The cap rocks sealing the reservoir in the Węglówka oil field, sub-Silesian unit, Polish outer Carpathians: Petrographical approach

The Weglowka oil field is located in the outer Carpathians. The outer Carpathians are a region where hydrocarbons were discovered and exploited at the end of the nineteenth century in several dozen oil fields, which are relatively small. The Weglowka oil field is one of the largest in this region. In the 150 yr or so of hydrocarbon exploration in the area, more than 1 million t (>1,237,000 tons [>8,841,000 bbl]) of oil have been produced. Hydrocarbons are concentrated in Lower Cretaceous sandstones (Grodziszcze and Lgota sandstones) that form an anticline sealed by Upper Cretaceous marls called the Weglowka marls. These cap rocks are up to 600 m (2000 ft) thick. Because of the thrust-related exhumation, they were exposed at the surface and represent the youngest deposits in the region. The present work is focused on a detailed petrographic characterization of the Weglowka marls. This study allows petroleum geologists to better understand the evolution of porosity in these cap rocks and can serve as a foundation for the prediction of their sealing properties. The marls appear as a succession of interbedded red and green varieties, which occur in up to 2-m (6-ft)-thick beds. These beds are nonarenaceous, soft, and bioturbated. Grain size corresponds to approximately 80% clay and less than 20% silt fractions. X-ray diffraction (XRD) reveals that the marls contain, on average, 54% clay, 28% calcite, 16% quartz, up to 3% feldspars and, in red marls, 3% hematite. The XRD patterns of clay are typical of mixed-layer illite–smectite ([I–S]; 40% illite in I–S). The clay structures are dioctahedral with similar octahedral Mg and relatively high Fe3+ contents both in the red and green intervals. As revealed by standard petrography combined with high-resolution petrography performed through the use of a field emission scanning electron microscope, the marls have mudstone textures according to Dunham’s (1962) classification and are mostly composed of coccoliths and clay with rare nanoquartz. This rock may be considered an impure chalk. Sealing properties of the Weglowka marls are indicated by the specific surface area, porosity, pore size, and permeability, calculated using N2 gas adsorption, helium, and mercury porosimetry. The sealing potential is postulated to result from a combination of the following: (1) origin of components (i.e., deposition of minute calcareous bioclasts and volcanic material as a source for clay); (2) oxygenated sedimentary environment (as a result of the presence of oxygen in the sediments, burrowing caused the rocks to be homogenized); and (3) tectonic-induced clogging of pore space because of reorganization of clay flakes (the rocks were strongly tectonically deformed, which resulted in reduction of porosity in clay aggregates).