Scanning Electron Microscopy Research Articles

A Cobalt-based Nanostructured Electrode Prepared by a Fast Chemical Method

The demand for nanomaterials is rapidly increasing in most applications, such as energy storage devices. Many nanomaterial synthesis methods are energy-consuming methods requiring high temperatures, prolonged reaction time, complicated steps, or expensive equipment. Herein, nanostructures of cobalt hydroxide chloride, Co2(OH)3Cl, have been directly deposited on carbon cloth microfibers by a fast and simple step of chemical bath deposition. Co2(OH)3Cl nanoparticles appear in only 10 minutes of the deposition time, then the nanoflakes are grown in 60 minutes, as imaged by scanning electron microscope. The crystal structure of Co2(OH)3Cl is characterized using X-ray diffraction, while the results of energy-dispersive X-ray spectroscopy confirm the elemental analysis. The electrochemical energy storage mechanism of Co2(OH)3Cl electrode in potassium hydroxide electrolyte depends on the semi-reversible redox reactions as investigated by the cyclic voltammetry and by the galvanostatic charge-discharge measurements. As a result, the prepared electrode in 60 min exhibits a maximum specific capacitance of 313 F/g versus 293 F/g for the prepared electrode in 10 min, both at 1 A/g. The good electrochemical performance is attributed to several features, including the nanoflakes morphology that enables electrolyte ions to penetrate the electrode freely, the well-crystallized structure, and the solid electronic path between the current collector and the active material indicated by the Nyquist plot of electrochemical impedance spectroscopy. Our cost-effective synthesis of cobalt hydroxide chloride nanostructures on woven substrates offers flexible binder-free electrodes in alkaline electrolytes. This research opens up the potential for these materials to be used as a power source in smart textiles and wearable electronics, thereby contributing to the advancement of these fields.

Auto-ponderomotive beam guiding up to 9.5 keV

We report successful electrostatic auto-ponderomotive (APE) electron beam guiding at electron energies of up to 9.5keV. We do so with electrons derived from a scanning electron microscope and demonstrate the guiding along an S-shaped trajectory. For this S-shaped guide, we use a mirror-symmetrical double-planar electrode layout and apply static voltages only. We study details of the APE guiding process and show that we can extend its operability over almost three orders of magnitude in beam energy. In particular, we reach a range of electron energies often used in conventional scanning electron microscopes.

Polyethersulfone/fish-shrimp chitosan-based mixed matrix membrane for industrial wastewater treatment.

In this study, chitosan (CH) was synthesized by processing of fish-shrimp solid waste (shell). It was utilized in the preparation of polyethersulfone (PES)-based mixed matrix membrane (Mx/CHy) through the film casting method. The hydrophilicity of the membrane was modified by increasing the concentration of CH. The degree of deacetylation (DD%) of CH, analyzed using the acid-base titration method, was found to be 78%. The molecular weight cutoff (MWCO) of the membrane was analyzed using the polyethylene glycol rejection method. The surface properties such as mean pore size and hydrophilicity of the membrane were analyzed using a scanning electron microscope (SEM) micrograph and water contact angle meter. The membrane (M18/CH1.0) mean pore size and MWCO were 7.0nm and 1.8kDa, respectively, which is in the nanofiltration (NF) range. After cross-linking of CH with PES/PVP, hydrophilicity and porosity of the M18/CH1.0 increased. The feasibility of the membrane was tested for the treatment of industrial wastewater (iron and steel, distillery, and paper and pulp industry) by varying the feed pressure. The collected permeate through the M18/CH1.0 for all industrial wastewater was transparent. The M18/CH1.0 showed the removal efficiency as follows: turbidity, 65%; total dissolved solids (TDS), 86.6%; total suspended solids (TSS), 60.5%; chemical oxygen demand (COD), 99.5%; biochemical oxygen demand (BOD), 99.5%; and electrical conductivity (EC), 63.2% of distillery industry wastewater. In the case of steel and iron wastewater, it showed the removal efficiency for TDS, 48.3%; TSS, 65.3%; and EC, 42.2%. However, M18/CH1.0 removed the turbidity, 94.5%; TDS, 65.7%; TSS, 97.6%; and EC, 85.5% from the pulp and paper industry wastewater feed. The strong removal efficiency and resistance towards the fouling of the M18/CH1.0 make it a potential candidate for the application in the treatment of industrial wastewater.

Morphological analysis of regenerated antennae in the isopod Porcellio scaber (Isopoda, Crustacea), with emphasis on the main sensory structures

The second antennae, an important sensory organ of terrestrial isopods, are often attacked and amputated by predators or members of the same species. If an amputation does happen, the antenna usually regenerates after the very first or the next moult that follows. However, the new regenerated antenna is smaller than the original one. This raises the question of whether a smaller regenerated antenna is potentially also less functional as the sensory elements of the antenna undergo regeneration as well. In this study, the regeneration process of the second antenna of Porcellio scaber was followed after two consecutive amputations. The original antennae were compared with the regenerated ones under light and scanning electron microscopes in view of the dimensions of segments and the size and number of sensory elements on them. As expected, all regenerated antennae were reduced in size, however, the reduction of different antennal segments was different. The second segment of the flagellum was reduced by almost half as much as the first segment of the flagellum or the last segment of the peduncle. After the next consecutive amputation, the reduction of the regenerated antennae does not increase further. The size and shape of the apical organ and lateral seta did not change during the regeneration process, neither after the first nor after the next amputation. In contrast, the number of plural receptor elements, such as aesthetascs and tricorn sensilla, decreases in accordance with reduced segment size. Therefore, since only the number of the most common sensory structures is reduced during regeneration, the regenerated antenna probably retains its sensory functionality.

Isolation and Characterisation of Acid Soluble Collagens and Pepsin Soluble Collagens from Eel (Anguilla japonica Temminck et Schlegel) Skin and Bone

Eel (Anguilla japonica) is an important and valuable food fish in East Asia and its by-products have been reported to include bioactive and profitable components. This study aimed to extract, characterise, and compare the structure and properties of acid-soluble collagens (ASCs) and pepsin-soluble collagens (PSCs) from the skin and bone of eel (Anguilla japonica), providing insights into their composition, structure, and properties for various applications. The yields of ASC-S (from skin), PSC-S (from skin), ASC-B (from bone), and PSC-B (from bone) were 12.16%, 15.54%, 0.79%, and 1.34% on a dry weight basis, respectively. Glycine, the dominant amino acid, accounted for 16.66% to 22.67% of total amino acids in all samples. SDS-PAGE and FTIR analyses showed the typical triple-helical structure of type I collagen with slight variations in molecular order in extract and intermolecular cross-linking between skin and bone collagens. The denaturation temperature (Tmax1) measured by differential scanning calorimetry (DSC) is 81.39 °C and 74.34 °C, respectively, for ASC-B and ASC-S. Bone collagen has higher thermal resistance than skin collagen. Surface morphology imaged using a scanning electron microscope (SEM) showed that the bone collagen had a denser network structure, whilst the skin collagen was more fibrous and porous. The findings suggest that eel-derived collagens from skin and bone can serve as potential alternatives in the food, cosmetic, and healthcare industries.

Technological transmission of knowledge in Neolithic northwestern China: mineralogical and chemical analyses of Yangshao and Majiayao painted ware

Thirty-eight Neolithic sherds from Yangshao and Majiayao period contexts were analysed via polarised light microscopy and by scanning electron microscope used with energy dispersive spectroscopy (SEM–EDX). Sixteen sherds come from the early Yangshao-period Banpo site in the Wei River Valley, east of Xi’an, 17 from the eponymous site of Majiayao and five from Waguanzui in the upper Yellow River region in eastern Gansu province. SEM–EDX was also used to measure the chemical composition of the clays and the paint (black, or in one case, red and white) applied to the ceramic surfaces. The analyses were carried out to detect differences or similarities in the chaînes opératoires of ceramic production at the three sites, in particular, to examine the clay types selected to make the three main categories of wares for which Yangshao and Majiayao are known, namely painted fine wares, burnished fine wares, and unpainted coarse wares. The results show that similar raw material selection and processing and technological choices were followed at the three sites to make both fine and coarse wares. At all sites, black paint was made by adding different mixtures of manganese and iron oxides to levigated clays, in a few cases possibly using the same levigated clay used to make the vessels themselves.

The influence of thermal tempering on the fracture resistance, surface microstructure, elemental surface composition, and phase analysis of four heat-pressed lithia-based glass ceramic crowns

BackgroundThis in-vitro study aimed to evaluate the impact of thermal tempering and ceramic type on the fracture resistance, surface microstructure, elemental surface composition and phase analysis of four heat-pressed glass ceramics.MethodsA total of 84 glass-ceramic crowns were pressed and randomly allocated into four equal groups (n = 21) according to the ceramic type: Group (E): IPS e.max Press, Group (L): GC initial LiSi Press, Group (C): Celtra Press and Group (A): VITA Ambria. The crowns of each group were equally allocated into three subgroups (n = 7) regarding the subsequent thermal tempering temperature. Subgroup (T0): No tempering. Subgroup (T1): Tempering at 9% below pressing temperature. Subgroup (T2): Tempering at 5% below pressing temperature. Samples were tested for fracture resistance using a universal testing machine. A scanning electron microscope, X-ray diffraction, and Energy Dispersive x-ray analysis were utilized to disclose the microstructural features.ResultsWhen there is no tempering, IPS e.max press showed a significant elevated fracture resistance (P-value = 0.002). There was an insignificant difference between other ceramics. While with tempering (T2) as well as (T1), Lisi press (L) showed a significant elevated fracture resistance. There was an insignificant difference between other ceramics (P-value = 0.004).ConclusionsIncorporation of zirconia oxide into the lithium disilicate glass matrix did not show improvement in the fracture resistance. Thermal tempering procedure had significant effect on fracture resistance. Thermal tempering technique had no influence the elemental surface composition and phase analysis yet T2 samples showed changes in crystal size and orientation.

Deterioration of White Tempera Mock-Ups Paints in a SO2-Rich Atmosphere

Historical tempera paints exposed to pollutant gases suffer chemical and mineralogical deterioration which manifests through physical changes. Knowledge about these changes is fundamental to develop strategies for preventive conservation of wall paintings. In this research, binary tempera mock-ups composed of calcite, gypsum or lead white mixed with a proteinaceous binder (i.e., egg yolk or rabbit glue) were exposed to an aging test by using SO2-rich atmosphere exposure to learn about the degradation mechanisms and forms related to the pigment–binder interaction. Reference (unaltered) and aged mock-ups were studied from a physical point of view, characterizing the morphological changes by using stereomicroscopy and profilometry, color variations by using spectrophotometry, gloss changes, and reflectance changes by using a hyperspectral camera. Also, mineralogical and chemical changes were studied by means of X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy with energy-dispersive X-ray spectroscopy. Egg-yolk-based paints showed higher chromatic changes than their counterparts made of rabbit glue binder. Also, sulfate and sulfite salts precipitated on the surface of the aged paints regardless of their binder, influencing the painting reflectance which subsequently increased. Egg-yolk-based mock-ups exhibited roughness increases while the rabbit-glue-based paints showed roughness reduction, with the exception of lead-white-based paints. Therefore, the important influence of the type of binder and the interaction between the binder and the pigment on the durability of tempera paints in atmospheres rich in SO2 was confirmed.

Laser-induced damage thresholds in SiO2-coated aluminum mirrors under various ultrashort pulse widths

The influence of laser temporal parameters on the laser-induced damage threshold (LIDT) is particularly complex due to the variation and uncertainty in damage mechanisms associated with different pulse widths, especially in the range that bridges transitional damage mechanisms. Metallic mirrors are ideally suited for ultrashort pulse optical systems owing to their broad spectral range. A comprehensive understanding of the damage behavior of metallic mirrors under ultrashort pulse widths is crucial for optimizing their performance and manufacturing processes. Consequently, a laser damage testing platform was established in the laboratory to conduct 1-on-1 and area-based damage testing method on SiO2-coated aluminum mirrors, covering a pulse width range of 0.2 to 11 ps. The experimental results revealed two transitions in the LIDT from 0.2 to 11 ps. Specifically, within the 0.3 to 8 ps pulse width range, the LIDT inversely correlated with the pulse width, adhering to a power-law relationship. Conversely, for pulse widths below 0.3 ps and between 8 and 11 ps, the LIDT positively correlated with the pulse width. Observations using optical microscopy and scanning electron microscopy (SEM) exhibited the damage morphology at different pulse widths, which indicated that damage initially occurred in the SiO2 dielectric film on the sample surface, demonstrating a transition in the laser damage mechanism across the experimental pulse width range.

Enhancing the tensile strength and morphology of Sansevieria trifasciata Laurentii fibers using liquid smoke and microwave treatments: an RSM approach

Liquid smoke (LS), an eco-friendly substance, is effective in modifying natural fibers to enhance their mechanical properties, surface morphology, and thermal stability. This study investigates the effects of LS immersion followed by microwave treatment on the tensile strength, surface morphology, and thermal characteristics of Sansevieria trifasciata Laurentii (STL) fibers. Response surface methodology (RSM) with central composite design (CCD) was used to optimize treatment parameters, including LS immersion time, microwave heating temperature, and duration. Mechanical, morphological, structural, and thermal properties were analyzed using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Optimal treatment conditions: 120 min LS immersion and microwave heating at 40 °C for 30 min. They resulted in a tensile strength of 370.23 MPa, a 37.21% improvement compared to untreated fibers. Treated fibers exhibited enhanced thermal stability, increased crystallinity, and improved surface morphology. These findings demonstrate that LS and microwave treatments effectively enhance STL fibers’ mechanical properties, surface morphology, and thermal stability, positioning them as promising reinforcement materials for sustainable composite applications.

Management of dental implant components following abutment screw loosening: A case report.

Management of implant abutment screw loosening should go beyond simply retightening the abutment screw. This case report highlights the need to check all components for damage before disinfection and re-tightening if possible. Major concerns include the implant-abutment connection site, screw, and debridement of the internal implant surfaces. Scanning electron microscopy and optical microscopic exam of the debris removed after cleaning demonstrated the presence of titanium metal particles and biological material. Protocols should be developed to address these issues before reattaching the implant restoration.

Chitosan-Bentonite composite adsorption of herbicide glyphosate from water solution.

This study highlights the use of Chitosan-Bentonite composites as an eco-friendly and cost-effective alternative to traditional adsorbents, which are often expensive and less accessible. Chitosan-Bentonite composite (CBC) samples with various chitosan/bentonite ratios (2/1, 2/2, 2/4, 2/8, and 2/10) were developed to remove glyphosate, one of the most widely used herbicides globally, from contaminated aqueous solutions. The CBC samples were characterized using complementary techniques such as X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analyses were performed. FTIR revealed OH vibrations at 3630cm⁻1 and -NH₂ and -NH₃⁺ at 1517cm⁻1, indicating electrostatic interactions between chitosan and bentonite. The NH₂ band at 1514cm⁻1 was absent in CBC 2/8 and CBC 2/10 due to low chitosan content. XRD analysis showed that the interaction between chitosan and bentonite significantly altered crystalline characteristics, reducing bentonite crystallinity and shifting reflection peaks, indicating effective chitosan intercalation. SEM images showed a non-porous lamellar structure for chitosan and reduced porosity in the composites, indicating exfoliation after interaction. The adsorption study revealed that the mass ratio influenced glyphosate adsorption capacity, with CBC 2/8 showing the best performance. Adsorption parameter analysis showed that the 2/8 Chitosan-Bentonite ratio, with an equilibrium adsorption capacity of 1.18mg/g, was the most effective for glyphosate removal. Optimal conditions were found at pH 3.76, using 50mg of CBC adsorbent, an initial glyphosate concentration of 10mg/L, and a contact time of 8h. Adsorption on the CBC 2/8 composite increased with concentration, reaching 2.8mg/g at equilibrium (Ce = 10.98mg/L). The S-type isotherm suggested that glyphosate is monofunctional with moderate intermolecular interactions. The Langmuir model indicated a maximum adsorption capacity (qm) of 133mg/g with moderate affinity (KL = 0.0018 L/mg). The Freundlich model, with an adsorption intensity coefficient (n) of 0.912, showed favorable adsorption, while low χ2 (0.450) and SSE (0.330) values indicated a slightly better fit to the data. Compared to costly synthetic materials, the CBC composite provides an economical and non-toxic option for wastewater decontamination, offering moderate but promising results for glyphosate removal. This study highlights the potential of chitosan-based composites to provide viable and sustainable solutions for managing agricultural pollutants.

The Application of Al-Pillared Clays Impregnated with Cerium and Al/Ce-Pillared Clays for the Treatment of Simulated Textile Effluents Through Photocatalysis

The objective of this study is to utilize a simulation employing advanced oxidation processes (AOPs) from photodegradation to examine the treatment of textile effluents. The selection of textile effluents as the material to be degraded is justified by the significant volume of water containing dyes, such as methylene blue (MB), generated daily by the textile industry. Often, this water is discarded without undergoing effective treatment. The purification of textile effluents would enable the reuse of water within the textile production cycle, thereby promoting sustainability. This study focuses on AOPs, which are extensively utilized in photocatalytic processes. The catalytic precursor material consists of two types of clay: a commercial clay and a natural clay. The natural clay is pillared with Al and impregnated with Ce, while the commercial clay is also pillared with Al and impregnated with Ce. Both clays are also pillared with a mixed pillar of Al and Ce. This results in three comparable materials. These clays are characterized by the presence of montmorillonite as their predominant mineral component. The selected clays were commercial bentonite and natural clay (FCN). Photocatalytic performance validation tests were conducted using UV-Vis spectroscopy. Material characterization methods included crystallographic analysis (by X-ray diffraction (XRD)), chemical composition (by X-ray fluorescence (XRF)), morphological studies (by scanning electron microscopy (SEM)) and textural property analysis (by N2 adsorption). The outcomes of these investigations offer signification insights into the potential applications of these materials in the treatment of textile effluents and the development of more sustainable processes within the textile industry. Furthermore, the results contribute to the advancement of photocatalytic material design.

Development of polyvinyl chloride composites with enhanced mechanical properties using modified ceramic particles

Abstract The integration of ceramic particles into polyvinyl chloride (PVC) composites offers a promising approach and has garnered significant attention due to their potential for enhancing mechanical properties. This work investigated the development and characterization of PVC composites enhanced with modified ceramic particles. Ceramic particulates, clays, and other mineral rock materials (non-plastics) with activators were processed and incorporated into the PVC matrix at varying weight percentages (5–30 wt%) and particle sizes (40–80 µm). The ceramic–PVC mixtures were synthesized using hot compression molding under specific conditions of 75 MPa pressure and 160 °C temperature. Mechanical properties’ testing was conducted using ASTM D3039 standards, covering flexural, tensile, hardness, and impact tests for comprehensive characterization. Microstructural analysis was performed using scanning electron microscopy (SEM). Results indicated that ceramic reinforcement significantly enhanced the mechanical properties of PVC composites, with notable improvements in flexural strength, tensile strength, hardness, and impact resistance. Moreover, the impact of particle size was crucial, as microstructural analysis revealed improved interfacial bonding between ceramic particles and PVC matrix, particularly with finer particle sizes (40 µm), suggesting better stress transfer. The findings demonstrated that including modified ceramic particles can substantially improve the performance of PVC composites, making them suitable as high-strength construction tiles and impact-resistant flooring. Graphical abstract

Hydrothermally grown cobalt phosphate hydrate microflowers for supercapacitors: Effect of reaction temperature

In this work, cobalt phosphate hydrate (Co3(PO[Formula: see text]8H2O) was deposited on Ni-foam using the facile hydrothermal method with varied reaction temperatures as 120°C, 150°C and 180°C. The X-ray diffraction analysis reveals the C2/m space group of cobalt phosphate hydrate (CoPH) with a monoclinic crystal structure. Scanning electron microscopy (SEM) evaluates the effect of different reaction temperatures on the morphology of deposited thin film. The change in morphology from microflakes to three-dimensional (3D) microflowers is observed due to temperature variation. In the electrochemical study, the C2 (150°C) electrode delivers a specific capacitance of 8798[Formula: see text]mF/cm2 (specific capacity 1.466[Formula: see text]mAh cm–2) at 30[Formula: see text]mA cm[Formula: see text] current density. Here, 70.65% of coulombic efficiency was observed over 1500 cycles. The energy density of 0.439[Formula: see text]Wh/cm2 and power density of 9[Formula: see text]mW/cm2 were delivered by optimized CoP electrodes, respectively. EIS study reveals the Rs values of C1, C2 and C3 electrodes are 1.49, 0.97 and 1.3 [Formula: see text], respectively.

Silicon-Based Sodium Hydride Core-Shell Structure for Portable Hydrolytic Hydrogen Generation.

Hydrogen production from silicon (Si) hydrolysis is environmentally friendly, safe, portable, and promising. However, the self-protected oxide layer around Si and a sluggish hydrolysis rate impede its practical utilization. To address this problem, we introduced sodium hydride (NaH) to form the core-shell structure of NaH/Si composites via a straightforward one-step, hand-mixing method in an ambient environment. NaH-based Si-M composites exhibit 83% hydrogen yield and a 52.7 mL/min hydrogen generation rate at 1-0.7 molar ratios. The hydrolytic activity includes the breakdown of NaH and the continuous hydrolysis of Si. X-ray diffraction, scanning electron microscopy, nanoindentation, and reaction observation studies have verified that NaH is pivotal in promoting thorough Si hydrolysis and attaining the maximum achievable yield compared to calcium hydride (CaH2). NaH/Si composites showed excellent hydrogen generation performance compared to CaH2/Si composites with microstructure silicon Si-S ≈ 1-3 μm, Si-M ≈ 75 μm, and Si-L ≈ 75-425 μm. Our study provided an innovative design and idea for utilizing cost-effective and easily transportable hydrogen production materials for practical applications, which has the potential for further advancement.

Real-time multimodal imaging of daptomycin action on the cell wall of adherent Staphylococcus aureus

ObjectivesThis study investigated the efficacy of daptomycin against adherent Staphylococcus aureus (S. aureus), a common colonizer of medical devices that leads to severe infections. For the first time, we evaluated the bactericidal effects of daptomycin on S. aureus immediately after adhesion, mimicking early-stage contamination of biomaterials. Time-kill curve assay and confocal laser scanning microscopy (CLSM) were used to analyze the process dynamics. In addition, atomic force microscopy (AFM) and scanning electron microscopy (SEM) were employed to elucidate daptomycin-induced structural changes in the bacterial cell wall.Results descriptionDaptomycin, at clinically relevant concentrations, rapidly eradicated adherent bacteria in the exponential growth phase, demonstrating an efficiency comparable to its action against planktonic cells. Prolonged exposure to the antibiotic caused marked alterations in the bacterial cell wall, including surface roughening and perforation, as revealed by multimodal imaging. However, daptomycin effectiveness diminished as biofilm formation progressed, underscoring the need for further exploration of optimized clinical strategies.

Two new diatoms of the genus Gomphosinica from Chumba Yumco, Xizang, China

This paper describes two new species of the genus Gomphosinica from Chumba Yumco, in the south of Kangma County, Xizang. The detailed morphological descriptions of the two new species, named Gomphosinica kangmaensis sp. nov. and G. chongbayongcuoensis sp. nov., are presented; the descriptions are based on light and scanning electron microscopy. The two species have the morphological characteristics that are typical for the genus Gomphosinica, including the striae composed of 2–3 rows of areolae, a prominent stigma with a round external opening and internal opening with a siliceous hooded structure comprised of many small, round openings, as well as the presence of septa and pseudosepta at the apices. G. kangmaensis sp. nov. and G. chongbayongcuoensis sp. nov. have morphological characteristics that mostly resemble those of G. selincuoensis W. Zhang, Q.M. You & Kociolek and G. lacustris Kociolek, You & Wang, respectively, but they differ from these species in details of the size, shape of valve and central area, the density of striae, the pattern of areolae, the position of apical pore-fields, and the deflection of raphe ends.

Effect of pore throats on the reservoir quality of tight sandstone: A case study of the Yanchang Formation in the Zhidan area, Ordos Basin

Abstract Due to the tight sandstone widespread development of nanoscale pore-throat systems, the microscopic pore-throat characteristics of tight reservoirs are the focus of research. Taking the main tight oil production province of the Ordos Basin in China as a case study, nuclear magnetic resonance (NMR), pressure-controlled mercury injection (PMI), scanning electron microscopy, and micro-computed tomography (μCT) are used to analyze the characteristics of four types of tight sandstones with different pore throats. Furthermore, the effects of pore throats on movable fluid, connectivity, and reservoir physical properties are analyzed. The results show that the pore throats of the four types of tight sandstones are obviously different, but they are all dominated by nanoscale pore-throat systems. From types I to IV, the pore types of the tight sandstone change from residual intergranular pores to the coexistence of feldspar dissolved pores and residual intergranular pores and then to the coexistence of residual intergranular pores and intergranular micropores. The T 2 NMR spectrum changes from a double peak to a single peak, the pore-throat connectivity revealed by μCT decreases from 83.8% for type I to 13.1% for type IV, the pore-throat volume ratio revealed by PMI decreases from 2.09 to 0.43, and the NMR movable fluid saturation decreases from 38.91 to 12.39%. Tight sandstone with larger pores and a uniform distribution has high movable fluid saturation and good pore-throat connectivity. Although the tight sandstone with dissolved pores and intergranular pores may have a medium porosity, the pore–throat connectivity deteriorates compared with high porosity sandstone. Large pore throats, which account for less than 15% of all pore throats, contribute more than 90% of the permeability, while pore throats less than 0.8 μm in diameter are major contributors to the reservoir space, and both the porosity and permeability decrease as the pore-throat diameter decreases.

Experimental Investigation of Mechanical Properties and Morphology of Ramie, Bamboo, and Ramie-Bamboo Hybrid Composites with Silicon Carbide and Alumina Nano-Fillers

Abstract The study explores the mechanical and morphological studies of ramie, bamboo, and hybrid ramie-bamboo composites with silicon carbide (SiC) and alumina (Al2O3) nano-fillers. The composites were fabricated using the hand-layup method followed by compression moulding. Mechanical characteristics such as tensile, flexural, impact, and hardness were investigated as per the ASTM standards. Surface characterization was performed using scanning electron microscopy (SEM) to understand the surface characteristics and failure behavior of composites. Experimental results indicated that the maximum tensile strength (50.16 MPa), impact strength (6.30 kJ/m2), and hardness (79.4) were obtained for the ramie-bamboo hybrid composite as compared to the other composites. The average flexural strength (101.4 MPa) of the pure ramie composite was superior to that of other composites. SEM micrographs revealed good fiber-matrix bonding in the hybrid composites. Ramie-bamboo hybrid composites with nano-fillers showed lower strength values due to the agglomeration of nano-fillers.