Search Results (124)

Enhanced Geothermal Systems (EGS) require thermochemically stable proppant materials capable of sustaining fracture conductivity under harsh subsurface conditions. This study systematically investigates the response of commercial proppants to coupled thermo-hydro-chemical (THC) effects, focusing on chemical stability and microstructural evolution. Four proppant types were evaluated: an ultra-low-density ceramic (ULD), a resin-coated sand (RCS), and two quartz-based silica sands. Experiments were conducted under simulated EGS conditions at 130 °C with daily thermal cycling over a 25-day period, using diluted site-specific Utah FORGE geothermal fluids. Static batch reactions were followed by comprehensive multi-modal characterization, including scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS), X-ray diffraction (XRD), and micro-computed tomography (micro-CT). Proppants were tested in both granular and powdered forms to evaluate surface area effects and potential long-term reactivity. Results indicate that ULD proppants experienced notable resin degradation and secondary mineral precipitation within internal pore networks, evidenced by a 30.4% reduction in intragranular porosity (from CT analysis) and diminished amorphous peaks in the XRD spectra. RCS proppants exhibited a significant loss of surface carbon content from 72.98% to 53.05%, consistent with resin breakdown observed via SEM imaging. While the quartz-based sand proppants remained morphologically intact at the macro-scale, SEM-EDS revealed localized surface alteration and mineral precipitation. The brown sand proppant, in particular, showed the most extensive surface precipitation, with a 15.2% increase in newly detected mineral phases. These findings advance understanding of proppant–fluid interactions under low-temperature EGS conditions and underscore the importance of selecting proppants based on thermo-chemical compatibility. The results also highlight the need for continued development of chemically resilient proppant formulations tailored for long-term geothermal applications. Full article

Capturing CO₂ emitted by coal chemical enterprises and injecting it into oil reservoirs not only effectively improves the recovery rate and development efficiency of tight oil reservoirs in the Ordos Basin but also addresses the carbon emission problem constraining the development of the region. Since initiating field experiments in 2012, the Ordos Basin has become a significant base for CCUS (Carbon capture, Utilization, and Storage) technology application and demonstration in China. However, over the years, projects have primarily focused on enhancing the recovery rate of CO₂ flooding, while issues such as potential reservoir damage and its extent have received insufficient attention. This oversight hinder the long-term development and promotion of CO₂ flooding technology in the region. Experimental results were comprehensively analyzed using techniques including nuclear magnetic resonance (NMR), X-ray diffraction (XRD), scanning electron microscopy (SEM), inductively coupled plasma (ICP), and ion chromography (IG). The findings indicate that under current reservoir temperature and pressure conditions, significant asphaltene deposition and calcium carbonate precipitation do not occur during CO₂ flooding. The reservoir’s characteristics-high feldspar content, low carbon mineral content, and low clay mineral content determine that the primary mechanism affecting physical properties under CO₂ flooding in the Chang 4 + 5 tight sandstone reservoir is not, as traditional understand, carbon mineral dissolution or primary clay mineral expansion and migration. Instead, feldspar corrosion and secondary particles migration are the fundamental reasons for the changes in reservoir properties. As permeability increases, micro pore blockage decreases, and the damaging effect of CO₂ flooding on reservoir permeability diminishes. Permeability and micro pore structure are therefore significant factors determining the damage degree of CO₂ flooding inflicts on tight reservoirs. In addition, temperature and pressure have a significant impact on the extent of reservoir damage caused by CO₂ flooding in the study region. At a given reservoir temperature, increasing CO₂ injection pressure can mitigate reservoir damage. It is recommended to avoid conducting CO₂ flooding projects in reservoirs with severe pressure attenuation, low permeability, and narrow pore throats as much as possible to prevent serious damage to the reservoir. At the same time, the production pressure difference should be reasonably controlled during the production process to reduce the risk and degree of calcium carbonate precipitation near oil production wells. Full article

Ceramic dental prosthetics with internal metal structures are made from a cobalt–chromium alloy that is coated with ceramic. This study aims to validate surface treatments for the metal that enhance the adhesion of the ceramic coating under masticatory forces. Surface conditioning is performed using mechanical methods, like sandblasting (SB), and thermal methods, such as oxidation (O). The ceramic coating is applied to the metal component following the conditioning process, which can be conducted using either a single method or a combination of methods. Each conditioned sample undergoes characterization through various techniques, including drop shape analysis (DSA), scanning electron microscopy (SEM), X-ray diffraction (EDX), and atomic force microscopy (AFM). After the ceramic coating is applied and subjected to thermal sintering, the metal–ceramic samples are mechanically tested to assess the adhesion of the ceramic layer. The research findings, illustrated by scanning electron microscopy (SEM) images of the metal structures’ surfaces, indicate that alloy powder particles ranging from 10 to 50 µm were either adhered to the surfaces or present as discrete dots. Particles that exceed the initial design specifications of the structure can be smoothed out using sandblasting or mechanical finishing techniques. The energy-dispersive spectroscopy (EDS) results show that, after sandblasting, fragments of aluminum oxide remain trapped on the surface of the metal structures. These remnants are considered impurities, which can negatively impact the adhesion of the ceramic to the metal substrate. The analysis focuses on the exfoliation of the ceramic material from the deformed metal surfaces. The results emphasize the significant role of the sandblasting method and the micro-topography it creates, as well as the importance of the oxidation temperature in the treatment process. Drawing on 25 years of experience in dental prosthetics and the findings from this study, this publication aims to serve as a guide for applying the ceramic bonding layer to metal surfaces and for conditioning methods. These practices are essential for enhancing the adhesion of ceramic materials to metal substrates. Full article

Background/Objectives: The work presented herein focused on the development and characterization of a transdermal caffeine platform fabricated from ultrathin micro- and submicron fibers produced via electrospinning. Methods: The formulations incorporated caffeine encapsulated in a polyethylene oxide (PEO) matrix, combined with various permeation enhancers. A backing layer made of annealed electrospun polycaprolactone (PCL) facilitated the lamination of the two layers to form the final multilayer patch. Comprehensive characterization was conducted, utilizing scanning electron microscopy (SEM) to assess the fiber morphology, attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) for chemical detection and to assess the stability of the caffeine, and differential scanning calorimetry (DSC) along with wide-angle X-ray scattering (WAXS) to analyze the physical state of the caffeine within the fibers of the active layer. Additionally, Franz cell permeation studies were performed using both synthetic membranes (Strat-M) and ex vivo human stratum corneum (SC) to evaluate and model the permeation kinetics. Results: These experiments demonstrated the significant role of enhancers in modulating the caffeine permeation rates provided by the patch, achieving permeation rates of up to 0.73 mg/cm² within 24 h. Conclusions: This work highlights the potential of using electro-hydrodynamic processing technology to develop innovative transdermal delivery systems for drugs, offering a promising strategy for enhancing efficacy and innovative therapeutic direct plasma administration. Full article

High-performance discontinuous carbon-fiber-reinforced thermoplastics (CFRTPs) offer promising manufacturing flexibility and recyclability for advanced composite applications. However, their mechanical performance and reliability strongly depend on the internal fiber architecture, which is largely determined by the molding process. In this study, three distinct compression molding approaches—CFRTP sheet molding compounds (SMCs), bulk molding compounds (BMCs), and free-edge molding compounds (FMCs)—were systematically evaluated to investigate how processing parameters affect fiber orientation, tape deformation, and impregnation quality. X-ray micro-computed tomography (XCT) was employed to visualize and quantify the internal structures of each material, focusing on the visualization and quantification of in-plane and out-of-plane fiber alignment and other internal structure features. The results indicate that CFRTP-SMC retains largely intact tape layers and achieves better impregnation, leading to more uniform and predictable internal geometry. Although CFRTP-BMC exhibits greater tape deformation and splitting due to increased flow, its simpler molding process and better tolerance for tape shape distortion suggest potential advantages for recycled applications. In contrast, CFRTP-FMC shows significant tape fragmentation and poor impregnation, particularly near free edges. These findings underscore the critical role of a controlled molding process in achieving a consistent internal structure for these materials for the first time. This study highlights the utility of advanced XCT methods for optimizing process design and advancing the use of high-performance discontinuous CFRTP in industry. Full article

Advanced packaging represents a crucial technological evolution aimed at overcoming limitations posed by Moore’s Law, driving the semiconductor industry from two-dimensional toward three-dimensional integrated structures. The increasing complexity and miniaturization of electronic devices have significantly heightened the challenges associated with failure analysis during process development. The focused ion beam–scanning electron microscope (FIB-SEM), characterized by its high processing precision and exceptional imaging resolution, has emerged as a powerful solution for the fabrication, defect localization, and failure analysis of micro- and nano-scale devices. This paper systematically reviews the innovative applications of FIB-SEM in the research of core issues, such as through-silicon-via (TSV) defects, bond interfacial failures, and redistribution layer (RDL) electromigration. Additionally, the paper discusses multimodal integration strategies combining FIB-SEM with advanced analytical techniques, such as high-resolution three-dimensional X-ray microscopy (XRM), electron backscatter diffraction (EBSD), and spectroscopy. Finally, it provides a perspective on the emerging applications and potential of frontier technologies, such as femtosecond-laser-assisted FIB, in the field of advanced packaging analysis. Full article

Objective: This study aims to analyze and evaluate the diagnostic methods used to detect multiple myeloma in paleopathological research. As a malignancy characterized by bone lesions, multiple myeloma presents unique opportunities for study through the paleopathological analysis of human skeletal remains. Methods: A literature review was conducted across PubMed, ScienceDirect, Embase, Scopus, Web of Science, and Google Scholar, focusing on macroscopic, radiological, and microscopic methods. A total of 43 original peer-reviewed studies published over six decades were selected. Results: The most commonly used diagnostic technique was macroscopic analysis of bone material, focusing on the characteristics of the lesions. Radiological methods, including X-ray, magnetic resonance imaging, computed tomography (CT), and micro-CT, provided complementary insights. Various microscopic techniques, chemical analyses, and fluoroscopy provided additional diagnostic detail. The diagnostic process is shaped by factors such as preservation, context, and access to technology; despite these variables, characteristic features of lesions were consistently recognized. Conclusion: This review highlights how macroscopic analysis remains central to diagnosis in paleopathology, with radiological and microscopic methods increasingly enhancing accuracy and interpretive depth. A multidisciplinary approach, combining macroscopic, radiological, microscopic, and chemical analyses where feasible, continues to strengthen paleopathological research and offers new insights into the historical presence of multiple myeloma. Full article

The quality of shale oil reservoirs is a major factor determining shale oil production capacity. Research on shale oil reservoirs has primarily focused on lithology. However, there has been little research on lithofacies classification. Moreover, there is still a lack of research on potential reservoir differences between different lithofacies and their controlling factors. In this context, the present study aims to classify the lithofacies of shale oil reservoirs in the Paleogene Shahejie Formation of the Jiyang Depression using different methods, including rock core and thin section observations, scanning electron microscopy (SEM) analysis, and X-ray diffraction (XRD). In addition, the characteristics and genesis of the high-quality shale oil reservoirs were studied using three-dimensional micro-CT scanning, low-pressure nitrogen adsorption, high-pressure mercury injection, and core physical property testing. The results showed better physical properties of combined shale and lenticular crystal limestone (C1), continuous parallel planar calcareous mudstone and uncontinuous laminate mudstone (C2), and continuous parallel planar calcareous mudstone and laminate mudstone (C3) compared with those of the other lithofacies; C1 exhibited the best physical properties. These three combined lithofacies consisted mainly of interconnected pores with medium and large pore throats, as well as fractures; the pore size mainly ranged from nanometers to micrometers. The high-quality reservoir conditions in combined lithofacies are the result of both basic sedimentary lithofacies and diagenetic history. The results of the current study provide new ideas and a useful reference for future related studies on mud shale reservoirs. Full article

Nanocomposite hydrogels are gaining significant attention for biomedical applications in soft tissue engineering due to the increasing demand for highly flexible and durable soft polymer materials. This research paper focused on investigating and optimizing a procedure for the development of novel nanocomposite hydrogels based on poly(2-hydroxyethyl methacrylate)-co-(2-acrylamido-2-methylpropane sulfonic acid) (HEMA/AMPSA) copolymers. These hydrogels were synthesized through a grafting-through process, where the polymer network was formed using a modified clay crosslinker. The layered double hydroxide (LDH) clay modified with 3-(trimethoxysilyl)propyl methacrylate (ATPM) was synthesized using a novel recipe through a two-step procedure. The nanocomposite hydrogel compositions were optimized to achieve soft hydrogels with high flexibility. The developed materials were analyzed for their mechanical and morphological properties using tensile and compressive tests, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and micro-computed tomography (micro-CT). The swelling behavior, network density, and kinetic diffusion mechanism demonstrated the specific characteristics of the materials. The modified LDH-ATPM was further characterized using Thermogravimetry (TGA), FTIR-ATR and X-ray diffraction (XRD). Biological assessments on human adipose-derived stem cells (hASCs) were essential to evaluate the biocompatibility of the nanocomposite hydrogels and their potential for soft tissue applications. Full article

Objectives: The indications for endoscopic submucosal dissection (ESD) for gastric adenoma and gastric cancer have expanded, leading to an increase in the number of patients with high procedural complexity. Post-ESD perforations prolong hospital stays and increase costs. However, no studies have focused on detecting micro-perforations during ESD. This study aimed to identify signs of perforation using abdominal ultrasound during gastric ESD. Materials and methods: This pilot study analyzed 50 patients who underwent abdominal ultrasound (VScan Air™, GE Healthcare) during ESD at Samsung Medical Center (March 2023–July 2024). Perforation was assessed via ultrasound, and post-procedure X-rays were performed for three days to detect free air. Results: Among 50 patients (median age 60, 76.1% male), the median procedure time was 60 min. Lesions were most common in the antrum (30.4%) and lesser curvature (17.4%). Pathology revealed 32.6% well-differentiated and 10.9% moderately differentiated adenomas, with 15.2% showing high-grade dysplasia. Free air was detected in three patients after procedures involving the body wall of the stomach. Abdominal US showed indirect signs of perforation, including an abnormal peritoneal line, hyperechoic shadowing, and an absence of normal gas patterns, confirmed by X-ray. Conclusions: Abdominal US is a simple, useful tool for rapid detection of perforation during ESD, enabling timely intervention. Further multicenter studies are needed to confirm these findings. Full article

Hangzhou was the political and economic center of the Southern Song Dynasty (1127–1279 AD) and also the southern end of the Beijing-Hangzhou Grand Canal during the Ming and Qing Dynasties (1368–1644 AD). This historical position allowed the city’s economy to develop rapidly and influenced the form of its polychrome paintings with the imperial official style of the north China. However, due to the high temperature and rainy natural preservation conditions, southern polychrome paintings have always been a weak link in Chinese architectural polychrome painting craftsmanship. This study focuses on two well-preserved official-style architectural polychrome paintings in the grand halls from the late Qing period in Hangzhou. Through multi-techniques such as optical microscopy (OM), scanning electron microprobe with energy dispersive X-ray spectroscopy analysis (SEM-EDX), micro-Raman spectroscopy, micro-Fourier Transform Infrared spectroscopy (μ-FTIR), and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), it was found that there is a significant difference from the reported common non-ground architectural paintings in the south, typically having four-layer structures with a white base and ground plaster layer in preparation for painting. The appearance of pigments such as artificial ultramarine (Na₆Al₄Si₆S₄O₂₀) and emerald green (Cu(C₂H₃O₂)₂·3Cu(AsO₂)₂) indicates that the paintings were made at least after the 1830s, and the use of malachite green dye and copper phthalocyanine blue (PB 15:X) suggests that unrecorded restorations were also performed after the 20th century. All samples are coated with a layer of alkyd resin, which may have been added during the repairs in the latter half of the 20th century, leading to the black discoloration of the present paintings, especially in areas where emerald green was used. This study provides an important case for the study of the official style of polychrome painting craftsmanship in the southern region of China and also offers important references for the future protection and restoration of traditional architectural polychrome painting. Full article

Waste slurry, a major by-product of urban construction, is produced in rapidly increasing volumes each year. Dehydrated waste slurry has potential as a roadbed material; however, its performance in freeze–thaw environments, which can induce frost heave and thaw settlement, and the mechanism of the influence of freeze–thaw cycles on its macro and micro properties are still unclear and need thorough investigation. This study explores the macroscopic and microscopic properties of waste slurry subjected to freeze–thaw cycles. We conducted unconfined compressive strength (UCS) and triaxial unconsolidated undrained (UU) shear tests, focusing on fissure compaction, elastic deformation, plastic yielding, and strain hardening stages. The results reveal a decrease in strength and elastic modulus with increasing freeze–thaw cycles, as well as in the damage degree generated by freeze–thaw cycles. To uncover the underlying microscopic mechanisms, we performed Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), and mercury intrusion porosimetry (MIP) analyses. These tests highlighted the evolution of pores and microcracks during freeze–thaw cycles. These results have important reference values for the reutilization of waste slurry discharged from large-diameter bored piles for roadbed backfill materials that need to be repaired quickly in seasonally frozen areas. Full article

Separation functions, so-called Tromp functions, are often used to quantitatively analyze the separation behavior in particle processing with respect to individual particle descriptors. However, since the separation behavior of particles is typically influenced by multiple particle descriptors, multivariate Tromp functions are required. This study focuses on methods that allow for the computation of multivariate parametric Tromp functions by means of statistical image analysis and copula-based modeling. The computations are exemplarily performed for the magnetic separation of Li-bearing minerals, including quartz, topaz, zinnwaldite, and muscovite, based on micro-computed tomography images and scanning electron microscopy with energy-dispersive X-ray spectroscopy analysis. In particular, the volume equivalent diameter, zinnwaldite fraction, flatness, and sphericity are examined as possible influencing particle descriptors. Moreover, to compute the Tromp functions, the probability distributions of these descriptors for concentrate and tailing should be used. In this study, 3D image data depicting particles in feed, concentrate, and tailings is available for the computation of Tromp functions. However, concentrate particles tend to be elongated, plate-like, and densely packed, making segmentation for extracting individual particles from image data extremely difficult. Thus, information on the concentrate could not be obtained from the available database. To remedy this, an indirect optimization approach is used to estimate the distribution of particle descriptors of the concentrate. It turned out that this approach can be successfully applied to analyze the influence of size, shape, and composition of particles on their separation behavior. Full article

Due to the unique properties of titanium dioxide (TiO₂), titanium oxide catalysts hold significant potential for photo-oxidative processes involving organic substances in liquid media. The current research has focused on developing new preparation methods that enable the manipulation of the properties, structure, and geometric shape of catalysts to enhance their efficiency in targeted reactions. This study developed a method for preparing Ag-SiO₂-TiO₂/TiO₂-Ag layered structures with a spherical shape, featuring particle diameters ranging from 232 to 653 μm and mesopores of 2–20 nm. This was achieved by combining sol–gel and template synthesis methods. A comprehensive analysis of the obtained materials was conducted using methods such as X-ray phase analysis, micro-X-ray spectral analysis, X-ray microanalysis, and scanning electron spectroscopy. The photocatalytic properties were assessed by measuring the degree of decomposition of methyl orange in a model oxidation reaction under light radiation. The obtained spherical Ag-SiO₂-TiO₂/TiO₂-Ag layered structures demonstrated high efficiency in the photooxidation of methyl orange in the model reaction. Full article

In this paper, an investigation focused on assessing the radon exhalation, the natural radioactivity level, and the mineralogy of natural stones of particular historical–artistic interest employed as building materials was carried out. The Closed Chamber Method (CCM) with the Durridge Rad7 apparatus for short-lived radon progeny alpha spectrometry and High Purity Germanium (HPGe) gamma spectrometry were used to determine the radon exhalation rate and specific activities of ²²⁶Ra, ²³²Th, and ⁴⁰K, respectively. Furthermore, several indices were evaluated to determine the radiological risk due to radiation exposure from the investigated natural stones, i.e., the absorbed gamma dose rate (D), the activity concentration index (ACI), and the alpha index (I_α). Finally, X-ray diffraction (XRD) and Micro-Raman Scattering (MRS) investigations were performed to correlate the chemical composition and mineralogical characteristics of natural stones with the radon exhalation rate and the natural radioactivity content. It is worth noting that the findings from this study can be used to guide future research into the background levels of radioactivity in stones used as construction materials. Full article