Search Results (74)

Sandstone reservoirs exhibit strong heterogeneity and complex microscopic pore structures, presenting challenges for quantitative characterization. This study investigates the Chang 8 tight sandstone reservoir in the Jiyuan, Ordos Basin through analyses of its physical properties, high-pressure mercury injection (HPMI), casting thin sections (CTS), and scanning electron microscopy (SEM). Deep learning techniques were employed to extract the geometric parameters of the pores from the SEM images. Fractal geometry was applied for the combined quantitative characterization of pore parameters and fractal dimensions of the tight sandstone. This study also analyzed the correlations between the fractal dimensions, sample properties, pore structure, geometric parameters, and mineral content. The results indicate that the HPMI-derived fractal dimension (D_MIP) reflects pore connectivity and permeability. D_MIP gradually increases from Type I to Type III reservoirs, indicating deteriorating pore connectivity and increasing reservoir heterogeneity. The average fractal dimensions of the small and large pore-throats are 2.16 and 2.52, respectively, indicating greater complexity in the large pore-throat structures. The SEM-derived fractal dimension (D_SEM) reflects the diversity of pore shapes and the complexity of the micro-scale geometries. As the reservoir quality decreases, the pore structure becomes more complex, and the pore morphology exhibits increased irregularity. D_MIP and D_SEM values range from 2.21 to 2.49 and 1.01 to 1.28, respectively, providing a comprehensive quantitative characterization of multiple pore structure characteristics. The fractal dimension shows negative correlations with permeability, porosity, median radius, maximum mercury intrusion saturation, mercury withdrawal efficiency, and sorting factor, while showing a positive correlation with median and displacement pressures. Among these factors, the correlations with the maximum mercury intrusion saturation and sorting factor are the strongest (R² > 0.8). Additionally, the fractal dimension is negatively correlated with pore circularity and major axis length, but positively correlated with pore perimeter, aspect ratio, and solidity. A higher proportion of circular pores and fewer irregular or long-strip pores correspond to lower fractal dimensions. Furthermore, mineral composition influences the fractal dimension, showing negative correlations with feldspar, quartz, and chlorite concentrations, and a positive correlation with carbonate content. This study provides new perspectives for the quantitative characterization of pore structures in tight sandstone reservoirs, enhances the understanding of low-permeability formation reservoir performance, and establishes a theoretical foundation for reservoir evaluation and exploration development in the study area. Full article

Archaean metamorphic basement reservoirs, characterized by the development of natural fractures, constitute the primary target for oil and gas exploration in the Bozhong Depression, Bohai Bay Basin, Eastern China. Based on analyses of geophysical image logs, cores, scanning electron microscopy (SEM), and laboratory measurements, tectonic fractures are identified as the dominant type of natural fracture. Their development is primarily controlled by lithology, weathering intensity, and faulting. Fractures preferentially develop in metamorphic rocks with low plastic mineral content and are positively correlated with weathering intensity. Fracture orientations are predominantly parallel or subparallel to fault strikes, while localized stress perturbations induced by faulting significantly increase fracture density. Open fractures, constituting more than 60% of the total reservoir porosity, serve as both primary storage spaces and dominant fluid flow conduits, fundamentally governing reservoir quality. Consequently, spatial heterogeneity in fracture distribution drives distinct vertical zonation within the reservoir. The lithological units are ranked by fracture development potential (in descending order): leptynite, migmatitic granite, gneiss, cataclasite, diorite-porphyrite, and diabase. Diabase represents the lower threshold for effective reservoir formation, whereas overlying lithologies may function as reservoirs under favorable conditions. The large-scale compressional orogeny during the Indosinian period marked the primary phase of tectonic fracture formation. Subsequent uplift and inversion during the Yanshanian period further modified and overlaid the Indosinian structures. These structures are characterized by strong strike-slip strain, resulting in a series of conjugate shear fractures. During the Himalayan period, preexisting fractures were primarily reactivated, significantly influencing fracture effectiveness. The development model of the fracture network system in the metamorphic basement reservoirs of the study area is determined by a coupling mechanism of dominant lithology and multiphase fracturing. The spatial network reservoir system, under the control of multistage structure and weathering, is key to the formation of large-scale effective reservoirs in the metamorphic basement. Full article

An understanding of the textures (grain size, grain shape, porosity, etc.), composition (mineralogy), and distribution of constituent components of geological materials such as carbonate and siliciclastic sedimentary rocks is essential in their classification, interpretation, and significance in terms of their geomechanical strength and liquid/gas storage potential. In terms of scanning electron microscopy (SEM), this is limited to relatively flat areas of selected rough surfaces, or the analysis of polished thin sections. Here, we illustrate a new technique that can image large areas of the external surface of mini-cores (approximately 10 mm or smaller in diameter) drilled from carbonate and siliciclastic rock samples. The technique utilises a specially developed horizontal rotation stage within an SEM and allows the collection of high-resolution images that can be reconstructed into realistic surface representations of the mini-core surfaces. Elemental data (representative of mineralogy) can also be added using a combined backscattered electron and X-ray (BEX) detector. Currently, these reconstructions can be used as a useful tool for the analysis of both carbonate and siliciclastic geological materials. Further work may allow such reconstructions to aid in the improvement of resolution in micro-CT scans and the direct identification of mineral phases within such scans. Full article

A simple method is developed to produce free-standing films of polypyrrole (PPy) in one step. It consists of the interfacial polymerization (without surfactants) of pyrrole (dissolved in chloroform) with an oxidant (ammonium persulfate, dissolved in water). It is observed that the area of the formed film only depends on the size of the interface, achieving the manufacture of PPy films of up to 300 cm², with a thickness of 200 microns. Transmission electron microscopy (TEM) images show the presence of superimposed nanoplatelets of ca. 100 nm main axis. These nanoparticles seem to aggregate in two dimensions to form the free-standing film. Scanning electron microscopy (SEM) shows a compact surface with nanowires decorating the surface. PPy films show an electrical conductivity of 63 (±3) S cm⁻¹. PPy conductive films are then applied in the construction of an antenna that shows a response in two bands: at 1.52 GHz (−13.85 dB) and at 3.50 GHz (−33.55 dB). The values are comparable to those of other antennas built with different PPy films. The simple synthesis of large-area PPy films in a single step would allow the fabrication of large quantities of electronic elements (e.g., sensors) with uniform properties in a short time. Full article

Textile industry waste contains high concentrations of heavy metals such as Pb(II) and Cr(VI) that must be reduced before they are released to the environment. The adsorption method is one way to reduce the heavy metal content. In this work, we develop a porous cellulose nanofiber (CNF) aerogel modified with graphene oxide (GO) as an alternative aerogel adsorbent for Pb(II) and Cr(VI). Cellulose was extracted from banana peduncle, a biomass waste that remains largely underutilized. The addition of GO aims to increase the adsorption properties. The aerogel adsorbents were synthesized by varying the ultrasonication time to 45 min for CNF 45 and 60 min for CNF 60, and the amount of GO added to 1 mL and 2 mL. The aerogel adsorbents were successfully prepared using the freeze-drying method with CNF45, CNF60, CNF45/GO1, CNF45/GO2, CNF60/GO1, and CNF60/GO2 variations. CNF was successfully isolated from a banana peduncle with an average diameter of 44.16 nm for 45 min (CNF 45) and an average diameter of 14.6 nm for 60 min (CNF 60) of ultrasonication. Chemical treatment and ultrasonication reduced the crystallinity index value of cellulose by 73% and 61% for CNF 45 and CNF 60, respectively. CNF aerogel has a very low shrinkage rate (<7%), resulting in a larger surface area. CNF60/GO2 obtained the optimum adsorption ability for Pb(II) metal at a concentration of 100 ppm and 27.27 mg/g at 30 min. On the other hand, the adsorption ability of Cr(VI) metal was obtained by CNF60/GO2 at a concentration of 100 ppm and 13.48 mg/g at 30 min. SEM images show that all aerogel adsorbents are porous, with a porosity value range of 96–98%. In conclusion, CNF60/GO2 proved to be the most effective aerogel adsorbent, offering the potential for heavy metal removal from industrial wastewater. Full article

The development of new graphene-based materials necessitates the application of suitable material imaging techniques, especially for the identification of defects in the graphene structure and its continuity. For this purpose, it is natural to use one of the main properties of graphene—electrical conductivity. In this work, we prepare a 9 cm² large-area monolayer graphene membrane on porous scaffolding sealed with either GO or rGO. Then, we use electrostatic force microscopy (EFM) AFM mode along with SE and AEE SEM modes to characterize the as-prepared graphene membranes thoroughly. The combination of SEM-AEE and AFM-EFM techniques not only assesses the quality of graphene itself but also characterizes the selectivity and effectiveness of masking graphene layer defects by applying GO or rGO. This makes these methods valuable in optimizing the production of advanced graphene nanocomposites such as semipermeable membranes. Full article

Polypropylene (PP) membranes have found diverse applications, such as in wastewater treatment, lithium-ion batteries, and pharmaceuticals, due to their low cost, excellent mechanical properties, thermal stability, and chemical resistance. However, the intrinsic hydrophobicity of PP materials leads to membrane fouling and filtration flux reduction, which greatly hinders the applications of PP membranes. Dielectric barrier discharge (DBD) is an effective technique for surface modification of materials because it generates a large area of low-temperature plasma at atmospheric pressure. In this study, O₂ was added to nanosecond pulsed Ar DBD to increase its reactivity. Electrical and optical diagnostic techniques were used to study the discharge characteristics of the DBD at varying O₂ contents. The uniformity of the discharge was quantitatively analyzed using the observed discharge images. Water contact angle measurements were used to assess the surface hydrophilicity of polypropylene. The surface morphology and chemical composition of the PP materials before and after treatment were analyzed using field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The results show that the moderate addition of O₂ enhances surface hydrophilicity and the uniformity of the modification. By increasing the O₂ addition from 0% to 0.1%, the average power increased from 4.19 W to 5.79 W, and the energy efficiency increased from 17.78% to 21.51%. The water contact angle of the DBD-treated PP showed a tendency to decrease and then increase with increasing O₂ content, with the optimum O₂ addition determined to be 0.1%. Under this condition, the water contact angle of the PP surface decreased by 31.88°, which is 52.31% lower than the untreated surface. O₂ increases the number of oxygen-containing polar groups (-OH, C=O, and O-C=O) on the surface of the material, and deepens and densifies the grooves on the surface of the PP material, resulting in an increase in the hydrophilicity of the PP surface. Full article

Developments in scanning electron microscopy (SEM) have introduced instant live coloured SEM images based on elemental composition. Here, we use a technique utilising a Unity BEX detector system, with collection speeds up to 100 times faster than typical standard energy-dispersive X-ray (EDX) analysis systems, to obtain large area backscattered and elemental composition maps of heavy mineral (HM) suites from a sample from an Oligocene fluvio-deltaic system in the Central Myanmar Basin. The fast X-ray collection rate and a high-resolution backscattered (BSE) detector allow for rapid imaging of polished blocks, thin sections, and stubs. Individual HM species can be rapidly classified, allowing for the subsequent collection of compositional and morphological metrics. In addition, the identification of grains such as zircon and apatite allow for further analysis by cathodoluminescence (CL) to identify and record the presence of growth zonation, which is critical for further U-Pb geochronology and thermochronology, using fission track analysis of apatite, zircon, and titanite. The sample used in this study contains a diverse heavy mineral suite due to the complex tectonic history of Myanmar, juxtaposing multiple metamorphic basement terranes alongside volcanic arcs and obducted ophiolites. This, along with the textural and mineralogical immaturity of the sediments themselves (governed by short transport systems and the rapid weathering of the sources), means that a wide variety of heavy mineral species can be identified and tested using this new technique, which provides a time-efficient method in comparison to traditional optical techniques. As the Unity BEX detector is located at the polepiece, it is relatively insensitive to working distance; in addition, the geometry of paired X-ray detectors on either side of the polepiece (at 180°) means that the system is also capable of fully characterising individual particles, on uncut and unpolished grain mounts, without artefacts such as particle shadowing. The development of a more comprehensive heavy mineral EDX database (library) will improve the accuracy of this new technique, as will the correlation with other techniques such as Raman spectroscopy. Full article

Microstructure degradation and phase transformations are critical concerns in nickel-based superalloys during thermal exposure. Understanding the phase transformation mechanism requires the detailed mapping of the distribution of each phase at different degradation stages and in various precipitation sizes. However, differentiating between phases in large areas, typically on the scale of millimeters and often relying on scanning electron microscopy (SEM) techniques, has traditionally been a challenging task. In this study, we present a novel and efficient phase mapping method that leverages multiple imaging detectors and modes in SEM. This approach allows for the relatively rapid and explicit differentiation and mapping of the distribution of various phases, including MC, M₂₃C₆, γ′, and η phases, as demonstrated in a typical superalloy subjected to aging experiments at 800 °C. Full article

Nanocellulose contains a large number of hydroxyl groups that can be used to modify its surface due to its structure. Owing to its appealing features, such as high strength, great stiffness, and high surface area, nanocellulose is currently gaining popularity in research and industry. The extraction of nanocellulose from the leftover bagasse fiber from sugarcane production by alkaline and acid treatment was successful in this study, with a production yield of 55.6%. The FTIR and XPS results demonstrated a difference in the functional and chemical composition of untreated sugarcane bagasse and extracted nanocellulose. SEM imaging was used to examined the size of the nanocellulose with ImageJ software v1.8.0. TGA, DTG, and XRD analyses were also performed to demonstrate the successful extraction of nanocellulose in terms of its morphology, thermal stability, and crystal structure before and after extraction. The anti-S. aureus activity of the extracted nanocellulose was discovered by using an OD₆₀₀ test and a colony counting method, and an inhibitory rate of 53.12% was achieved. According to the results, nanocellulose produced from residual sugarcane bagasse could be employed as an antibacterial agent. Full article

Grape dehydration is practiced widely in the food industry with large yields of sultanas produced globally. This paper proposes an investigation into the microstructure changes of grapes as they are dried by imaging specimens at intervals during dehydration at two temperatures using scanning electron microscopy. Two main methods were developed to obtain the complex boundaries of cells present in grape tissue in over 36 SEM images. Segmentation of the binary image using an adapted watershed function obtained the most consistent and accurate morphological shape. This was compared to a secondary method which used Canny’s edge detection function, morphological closing and skeletonizing to outline the cellular microstructure. MATLAB was utilised to convert these boundaries into measurable areas so that quantitative data on average cell area, perimeter and cell axis lengths were acquired. It was found that over the drying time, the cell area and perimeter were reduced as expected. Some variability in the data was clear due to only single samples being analysed for each temperature and time combination. Trends in cell perimeter, diameter and shape will be used to demonstrate relationships between morphological structure, drying temperature, and duration. Detailed images of the microstructure were obtained, and a unique image processing algorithm was developed to quantitatively analyse the properties of this microstructure. The development of automatic image processing techniques and algorithms will enable quantitative data to be extracted from any image and extend to any plant/food material. Full article

Steel slag micronized powder, granulated blast furnace slag, and cement were used as cementitious materials to prepare a foamed lightweight soil for roadbed filling to reduce the settlement and additional stress of the foundation and to solve the environmental problems caused by the storage of large amounts of steel slag. However, the instability of steel slag and the multi-angular nature of its surface limit the resource utilization of steel slag. Currently, concrete technology is unable to achieve a large amount of steel slag. Therefore, it is necessary to deeply explore the influence of steel slag content and the specific surface area of steel slag on the working performance, compressive strength, durability, and micro-mechanism of foam light soil. Through the modification of steel slag and the improvement of the production process, the preparation of foam light soil with a large amount of steel slag can be realized. In this study, the foamed lightweight soil with 1.0 Mpa was prepared by cementitious materials composed of 40% cement and 60% multi-mixture of steel slag micronized powder and granulated blast furnace slag. The study of SEM images and BET demonstrated that the larger specific surface area of steel slag powder was more conducive to improving the durability of the foamed lightweight soil. Meanwhile, XRD analyses confirmed that the reactions of f-CaO and f-MgO in steel slag were slowly released in the porous foamed lightweight soil system, which compensated for the shrinkage properties of porous materials. When the SSMP content was 0%, the shrinkage rate was 2.34 × 10⁻³, while when the SSMP content was 60%, the shrinkage rate was only 0.54 × 10⁻³. Furthermore, our study of the hydration process of samples indicated that the strong alkalinity of steel slag micronized powder hydration was helpful to stimulate the potential activity of the slag powder, which was beneficial to the improvement of the compressive strength of foamed lightweight soil. Thus, this study provides a valuable idea for reducing the settlement and additional stress of the original foundation and for solving the environmental problems caused by a large amount of steel slag storage. Full article

Nanotechnology can offer a series of new “green” and eco-friendly methods for developing different types of nanoparticles, among which the development of nanomaterials using plant extracts (phytosynthesis) represents one of the most promising areas of research. This present study details the use of lavender flowers (Lavandula angustifolia Mill., well-known for their use in homeopathic applications) for the biosynthesis of silver nanoparticles with enhanced antioxidant and antibacterial properties. Several qualitative and quantitative assays were carried out in order to offer an image of the extracts’ composition (the recorded total phenolics content varied between 21.0 to 40.9 mg GAE (gallic acid equivalents)/g dry weight (d.w.), while the total flavonoids content ranged between 3.57 and 16.8 mg CE (catechin equivalents)/g d.w.), alongside modern analytical methods (such as gas chromatography-mass spectrometry—GC-MS, quantifying 12 phytoconstituents present in the extracts). The formation of silver nanoparticles (AgNPs) using lavender extract was studied by UV-Vis spectroscopy, Fourier-transform infrared spectrometry (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and dynamic light scattering (DLS)/zeta potential, with the selected nanoparticles having crystallite sizes of approx. 14.55 nm (AgNP-L2) and 4.61 nm, respectively (for AgNP-L4), and hydrodynamic diameters of 392.4 nm (for AgNP-L2) and 391.6 nm (for AgNP-L4), determined by DLS. A zeta potential of around −6.4 mV was displayed for both samples while presenting as large aggregates, in which nanoparticle clusters with dimensions of around 130–200 nm can be observed. The biomedical applications of the extracts and the corresponding phytosynthesized nanoparticles were evaluated using antioxidant and antimicrobial assays. The obtained results confirmed the phytosynthesis of the silver nanoparticles using Lavandula angustifolia Mill. extracts, as well as their antioxidant and antimicrobial potential. Full article

Extended field-of-view ultrasound (US) imaging, also known as panoramic US, represents a technical advance that allows for complete visualization of large musculoskeletal structures, which are often limited in conventional 2D US images. Currently, there is no evidence examining whether the experience of examiners influences muscle shape deformations that may arise during the glide of the transducer in panoramic US acquisition. As no studies using panoramic US have analyzed whether two examiners with differing levels of experience might obtain varying scores in size, shape, or brightness during the US assessment of the rectus femoris muscle, our aim was to analyze the inter-examiner reliability of panoramic US imaging acquisition in determining muscle size, shape, and brightness between two examiners. Additionally, we sought to investigate whether the examiners’ experience plays a significant role in muscle deformations during imaging acquisition by assessing score differences. Shape (circularity, aspect ratio, and roundness), size (cross-sectional area and perimeter), and brightness (mean echo intensity) were analyzed in 39 volunteers. Intraclass correlation coefficients (ICCs), standard error of measurements (SEM), minimal detectable changes (MDC), and coefficient of absolute errors (CAE%) were calculated. All parameters evaluated showed no significant differences between the two examiners (p > 0.05). Panoramic US proved to be reliable, regardless of examiner experience, as no deformations were observed. Further research is needed to corroborate the validity of panoramic US by comparing this method with gold standard techniques. Full article

The increased demand for implants that do not pose a threat to patients diagnosed using high-resolution magnetic resonance imaging and concerns arising from titanium allergies require the development of alternative implant materials. One promising concept is a use of zirconium as corrosion-resistant, nontoxic material that is lower in magnetic susceptibility. To achieve this, safe and efficient surface treatment methods of zirconium metal have to be developed. In this study, zirconium samples were treated with fluoride-free and fluoride-containing etching mixtures to determine their effect on the surface of Zr. SEM images were taken to investigate the preliminary effects of the etchants. Then, a second set of experiments was carried out using mixtures of HF-H₂SO₄ and ammonium persulfate–fluoride salts, as they gave the most promising results in the first trial. SEM images were taken and measurements on roughness, wettability, and atomic composition were made. The results showed an even zirconium surface in APS-fluoride salts, along with the formation of pits (1–3 μm) similar to those found in commercially available implants. There was no significant increase in the roughness of the treated samples. The addition of NO₃⁻ ions in the form of KNO₃ speeded up etching and promoted pit formation. The HF-H₂SO₄ mixture was found to give unsatisfying results, as the surface was too rough and the formed pits were too large. It was concluded that etching zirconium in ammonium persulfate and fluoride salts is a promising area of research for the preparation of zirconium implants; however, further research has to be carried out on sandblasted samples. Full article