Structure Of Zone Research Articles

A study of structural effects on the focusing and imaging performance of hard X-rays with 20–30 nm zone plates

Hard X-ray microscopes with 20–30 nm spatial resolution ranges are an advanced tool for the inspection of materials at the nanoscale. However, the limited efficiency of the focusing optics, for example, a Fresnel zone plate (ZP) lens, can significantly reduce the power of a nanoprobe. Despite several reports on ZP lenses that focus hard X-rays with 20 nm resolution – mainly constructed by zone-doubling techniques – a systematic investigation into the limiting factors has not been reported. We report the structural effects on the focusing and imaging efficiency of 20–30 nm-resolution ZPs, employing a modified beam-propagation method. The zone width and the duty cycle (zone width/ring pitch) were optimized to achieve maximum efficiency, and a comparative analysis of the zone materials was conducted. The optimized zone structures were used in the fabrication of Pt-hydrogen silsesquioxane (HSQ) ZPs. The highest focusing efficiency of the Pt-HSQ-ZP with a resolution of 30 nm was 10% at 7 keV and >5% in the range 6–10 keV, whereas the highest efficiency of the Pt-HSQ-ZP with a resolution of 20 nm was realized at 7 keV with an efficiency of 7.6%. Optical characterization conducted at X-ray beamlines demonstrated significant enhancement of the focusing and imaging efficiency in a broader range of hard X-rays from 5 keV to 10 keV, demonstrating the potential application in hard X-ray focusing and imaging.

The geometry of fault reactivation and uplift along the central part of the Maacama Fault Zone, Northern California Coast Ranges (USA)

Fault reactivation of bedrock structures in active fault zones influences stress state and earthquake rupture phenomena through the introduction of weak slip surfaces that impact fault zone geometry and width. Yet, geometric relationships between modern faults and older reactivated faults are difficult to quantify in rocks that have experienced multiple deformation episodes. We used new geologic mapping, geomorphic tools, and structural modeling to quantify rock uplift and subsurface fault geometry of the central part of the Maacama Fault Zone near Ukiah, California, USA, and the surrounding area. Results suggest that the northern Mayacamas Mountains are in a tectonically driven disequilibrium, with differential rock uplift focused on the western side of the range. Steeply east-dipping fault surfaces and splays characterize the geometry of the Maacama Fault Zone. We mapped two newly identified faults to the east of the main Maacama Fault, the Cow Mountain–Mill Creek Fault, and Willow Creek Fault, which align with a moderately east-dipping cluster of microseismicity between 4–10 km depth beneath the Mayacamas Mountains. Static stress modeling on the Maacama Fault Zone and newly identified faults to the east quantify slip tendency values of 0.5–0.4, which suggests that the faults are moderately to poorly suited for slip in the modern stress field and may be weak. We infer that modern uplift is driven by oblique reverse, up-to-the-east, dip-slip motion on the reactivated Cenozoic Cow Mountain–Mill Creek and Willow Creek Faults as material is advected through a restraining bend on the Maacama Fault. This study shows that reactivated bedrock faults increase the fault zone width and introduce fault surfaces that contribute a component of vertical deformation and uplift in major strike-slip fault zones. Deformation is accommodated on an interconnected network of new and reactivated faults that delineate a complex seismic hazard.

Autographa californica multiple nucleopolyhedrovirus ac106 is required for the nuclear egress of nucleocapsids and intranuclear microvesicle formation.

Autographa californica multiple nucleopolyhedrovirus (AcMNPV) orf106 (ac106) is highly conserved in baculoviruses. Previous studies have shown that ac106 is required for the production of infectious budded virions (BVs). However, the functional role of ac106 in virion morphogenesis remains unknown. In this report, an ac106 knockout virus and an ac106 repair virus were constructed. The effect of ac106 deletion on virion morphogenesis was investigated, and the expression and subcellular localization of the Ac106 protein were characterized. Our data indicated that ac106 is required for the nuclear egress of nucleocapsids and intranuclear microvesicle formation, as well as subsequent BV and occlusion-derived virion (ODV) production and the embedding of ODVs into polyhedra. Ac106 is a baculovirus late protein that is concentrated in discrete foci of virus-induced membrane structures in the intranuclear ring zone of virus-infected cells. Further studies on the relationship between Ac106 and four other proteins that are also required for intranuclear microvesicle formation, Ac75, Ac76, Ac93, and P48 (Ac103), revealed that Ac106 is associated with Ac75, Ac76, Ac93, P48, and itself. Ac106 is required for Ac75, Ac93, and P48 accumulation in foci of virus-induced intranuclear membrane structures and the intranuclear transport of Ac76. Analysis of the subcellular localization of ODV integral envelope proteins upon deletion of the genes required for intranuclear microvesicle formation indicated that intranuclear microvesicle formation may be essential for ODV integral envelope protein transport into the nucleus, supporting the hypothesis that intranuclear microvesicles originate from the nuclear membrane.IMPORTANCEBaculovirus occlusion-derived virions (ODVs) are known to acquire their envelopes from virus-induced intranuclear microvesicles within the nucleoplasm, and this strategy of intranuclear envelopment of nucleocapsids to form virions is unique among viruses. However, the mechanism of ODV morphogenesis, particularly intranuclear microvesicle formation, remains unclear. In this study, we identified ac106 as the fifth gene, in addition to ac75, ac76, ac93, and p48 (ac103), which are required for intranuclear microvesicle formation. Further studies on the relationship between ac106 and the other four genes, as well as the effect of ac106 or ac75 deletion on the localization of ODV integral envelope proteins, indicated that intranuclear microvesicle formation may be essential for the transport of ODV integral envelope proteins into the nucleus, which strongly supports the hypothesis that intranuclear microvesicles originate from the nuclear membrane. These findings greatly enhance our understanding of the molecular mechanism of baculovirus ODV morphogenesis.

Identification of prospective oil-bearing areas in the peripheral parts of productive horizons U-12 and U-13 of the Zhetybai field

Background: To date, a comprehensive range of scientific, geological exploration, and appraisal work has been conducted at the Zhetybai field. The overall structural map of the field has been relatively well established. However, several critical issues remain insufficiently studied or entirely unexplored. Based on the results of seismic exploration (3D common depth point method) and additional appraisal work, peripheral (edge) zones of the field structure have been identified, including its cross-faults, as well as transverse flexures and longitudinal faults on the southern wing of the structure, which require further investigation. Aim: To further study the field structure, identify new potential hydrocarbon areas in the peripheral parts of the field, and assess the oil potential of the U-12 and U-13 horizons in the Zhetybai field. Materials and methods: This study involved a qualitative assessment of the informativeness of seismic attributes, analysis of reflection geometry (configuration), dynamic amplitude parameters, continuity of frequency, and other indicators. The analysis of reflection characteristics, in conjunction with all available data, primarily geophysical survey data, allowed for hypothesizing sedimentary conditions and obtaining acceptable lithological assessments. Results: The evaluation wells J-1, J-2, and J-3, drilled in 2023-2024 in the peripheral parts beyond the approved boundary of hydrocarbon-bearing horizons U-12 and U-13, yielded positive results. The productivity of the new reservoir was also confirmed by newly drilled production wells 5333, 5652, and 5367. Conclusion: To further study the structure of the Zhetybai field and identify new potential hydrocarbon-bearing areas in the peripheral parts, as well as structural uplifts and sandstone bodies of horizons U-12 and U-13, evaluation wells J-1, J-2, and J-3 were drilled. The detailed identification of sandstone bodies allows for the prediction of prospective areas not covered by drilling. The positive results from drilling evaluation wells have refined the geological structure of horizons U-12 and U-13 and confirmed the productivity of the peripheral parts of the reservoirs.

A hierarchical multistage holistic model for acoustic emission source monitoring in composites

Abstract This paper introduces a multistage smart structural health monitoring (SHM) model for carbon-fiber composites, with a focus on multiple types of acoustic emission (AE) source localization and classification. The SHM model uses time-frequency data from various AE events (such as tool drops, impact, and artificial debonding) across different zones of a composite structure. The SHM strategy demonstrates a robust smart monitoring of composites with high accuracy. Further, a hypothesis testing has been carried out that supports the superiority of a 2-stage identification process, revealing statistically significant higher accuracy and confidence intervals across all zones and AE source types. This research establishes a novel framework for solving a hierarchical multistage holistic damage source identification problem, offering robustness in identifying various damage scenarios and quantifying associated prediction uncertainties.

CLINICAL CASES OF SPITZOID NEOPLASMS

Spitz nevi account for about 2% of the total number of melanocytic skin neoplasms. There are benign Spitz nevi, atypical Spitz tumour, and malignant Spitz melanoma. These clinically similar lesions, usually represented by a flesh-coloured, pink or brownish-black spot or nodule, are often heavily vascularised, grow rapidly in size and change in structure, raising concerns about malignancy. Dynamic observations have revealed the possibility of long-term stabilisation and periods of regressive changes. Dermoscopy is used for early diagnosis due to the initially small size of nevi. When examining the magnified image of the tumour surface, the structure of the neoplasm is recognized. In the case of Spitz nevi, special patterns of “starburst” and “stardust” are identified, which allow to suspect the diagnosis and the period of involution, respectively. Pathohistologically, Spitz nevi are defined as melanocytic proliferations with large epithelioid or spindle-shaped melanocytes with large nuclei, vesicular chromatin and prominent nucleoli. However, the differentiation between different subtypes of spitzoid neoplasms remains a difficult issue. As of today, the review of H&E-stained structures still prevails over immunohistochemical and molecular genetic diagnostic methods. Even nowadays, Spitz nevi still cause difficulties in clinical and morphological diagnosis and management approaches. The publication considers several interesting cases from personal clinical practice. Case 1: Patient A, a 24-year-old woman. She complained of a single rash on the outer surface of the right thigh, which gradually increased in size over the last year. On clinical examination, a small erythematous, partially pigmented, heterogeneous nodule was observed in this area. The demonstrated Spitz nevus is heterogeneous in structure. Being in the phase of active growth, it showed an asymmetrical “starburst” pattern formed by vascular elements in a linear arrangement, and white reticular lines or structureless zones. Case 2: Patient B, 34 years old. A full examination of the right popliteal fossa revealed a heterogeneous spot up to 4 mm in diameter, which caused concern. A case of Spitz nevus is represented by a globular pattern in the centre and a reticular pattern on the periphery, which is more common for lesions that have been on the skin for some time, but no longer show signs of active growth. Case 3: Patient C, a 25-year-old woman, skin phototype 2, with a family history of skin tumours in several previous generations. The examination revealed a heterogeneous nodule of suspicious morphology in the left scapula. Dermoscopically, the above-described lesion is represented by two zones of different structure. The central zone has the signs of radial markings formed by various pattern elements; the polychromatic zone has areas of negative pigment network, white lines, dots and globules. There was also an eccentrically located area with a radially oriented hyperchromatic pigment network and a clear border along the outer edge. Most Spitz nevi are independent lesions, but some of them can be associated with other skin neoplasms. This is likely to be the example in the above-mentioned case, so it was the nevus-associated Spitz melanoma. Spitz nevi are an urgent problem of modern medicine. The similarity of the clinical, dermoscopic and pathological picture to malignant skin neoplasms causes diagnostic difficulties. Visual variability requires considerable clinical experience of a specialist.

Neodymium-Facilitated Visualization of Extreme Phosphate Accumulation in Fibroblast Filopodia: Implications for Intercellular and Cell–Matrix Interactions

A comprehensive understanding of intercellular and cell–matrix interactions is essential for advancing our knowledge of cell biology. Existing techniques, such as fluorescence microscopy and electron microscopy, face limitations in resolution and sample preparation. Supravital lanthanoid staining provides new opportunities for detailed visualization of cellular metabolism and intercellular interactions. This study aims to describe the structure, elemental chemical, and probable origin of zones of extreme lanthanoid (neodymium) accumulation that form during preparation for scanning electron microscopy (SEM) analysis in corneal fibroblasts filopodia. The results identified three morphological patterns of neodymium staining in fibroblast filopodia, each exhibiting asymmetric staining within a thin, sharp, and extremely bright barrier zone, located perpendicular to the filopodia axis. Semi-quantitative chemical analyses showed neodymium-labeled non-linear phosphorus distribution within filopodia, potentially indicating varying phosphate anion concentrations and extreme phosphate accumulation at a physical or physicochemical barrier. Phosphorus zones labeled with neodymium did not correspond to mitochondrial clusters. During apoptosis, the number of filopodia with extreme and asymmetric phosphorus accumulation increases. Supravital lanthanoid staining coupled with SEM allows detailed visualization of intercellular and cell–matrix interactions with high contrast and resolution. These results enhance our understanding of phosphate anion accumulation and transfer mechanisms in cells under normal conditions and during apoptosis.

Differences in the Genesis and Sources of Hydrocarbon Gas Fluid from the Eastern and Western Kuqa Depression

The Kuqa Depression is rich in oil and gas resources and serves as a key production area in the Tarim Basin. However, controversy persists over the genesis of oil and gas in the various structural zones of the Kuqa Depression. This study employs natural gas composition analysis, gas carbon isotope analysis and gold pipe thermal simulation experiments, to comprehensively analyze the differences in the genesis and sources of hydrocarbon gas fluid from the eastern and western Kuqa Depression. The results show that the Kuqa Depression is dominated by alkane gas, with an average gas drying coefficient of 95.6, with nitrogen and carbon dioxide as the primary non-hydrocarbon gases. The average of δ13C1, δ13C2 and δ13C3 values in natural gas are −27.70‰, −20.43‰ and −21.75‰, respectively. Based on comprehensive natural gas geochemical maps, the CO2 in the natural gas from the Tudong and Dabei areas, as well as the KT-1 well of the Kuqa Depression, is thought to be of organic origin. Additionally, natural gas formation in the Tudong area is relatively simple, consisting entirely of thermally generated coal gas derived from the initial cracking of kerogen. The natural gas in the KT-1 well and the Dabei area are mixed gasses, formed by the initial cracking of kerogen from highly evolved lacustrine and coal-bearing source rocks, exhibiting characteristics resembling those of crude oil cracking gas. The methane (CH4) content of natural gas in the Dabei area is high and the carbon isotopes are unusually heavy. Considering the regional geological background, potential source rock characteristics and geochemical features may be related to the large-scale invasion of dry gas contributed by CH4 from highly evolved, underlying coal-bearing source rocks. Consequently, the CH4 content in the mixed gas is generally high (Ln (C1/C2) can reach up to 5.38), while the relative content of heavy components is low, though remains relatively unchanged. Thus, the map of the relative content of heavy components still reflects the characteristics of the original gas genesis (initial cracking of kerogen). Mixed-source gas was analyzed using thermal simulation experiments and natural gas composition ratio diagrams. The contributions of natural gas from deep, highly evolved coal-bearing source rocks in the KT-1 well and the Dabei area accounted for more than 90% and approximately 60%, respectively. This analysis provides theoretical guidance for natural gas exploration in the research area.

Reaction zone structure of spontaneous reaction wave at steady subsonic and supersonic speeds

The reaction zone structure of spontaneous reaction wave at steady subsonic and supersonic speeds is discussed using numerical simulation and theoretical approaches. The main objective of this study is to develop the mathematical model of the spontaneous reaction wave propagating at a steady speed and to clarify the relationship between the reaction zone structure and non-dimensional parameters. A one-dimensional direct numerical simulation (DNS) of the spontaneous reaction wave propagation is performed, and the modeling assumptions are discussed based on the numerical results. The non-dimensional parameters, the Damköhler number and a parameter related to compressibility defined by the Mach number of the spontaneous reaction wave velocity, are introduced into the modeling. The mathematical model is developed using asymptotic techniques, and the solution of the reaction zone structure is analytically derived using Newton’s method. The relationship between reaction zone structure of spontaneous reaction wave and non-dimensional parameters is discussed based on the analytical solutions.

Cuartel Ophiolite: Structure, timing and exhumation mechanisms for a Cadomian suture zone in the peri-Gondwanan Realm (SW Iberia)

The Cadomian Orogeny formed as an accretionary orogen surrounding Gondwana. The structure resulting from the Cadomian Orogeny is pervasively reworked during the Paleozoic, within the frame of the Variscan Cycle. In SW Iberia (Mina Afortunada Massif), a tectonometamorphic and geochronological analysis revealed two Cadomian deformation phases. The first phase (DC1; 586 Ma, U-Pb dating in inherited metamorphic garnet from Mina Afortunada Gneiss) is associated with ophiolite accretion during the closure of a back-arc or intra-arc basin (Cuartel Ophiolite). A metamorphic fabric related to this phase is preserved as an internal foliation in Ediacaran (meta)sedimentary rocks. The second phase (DC2; 515–485 Ma) is constrained by the age of the igneous protolith of Mina Afortunada Gneiss (∼515 Ma), which is affected by a penetrative foliation formed during DC2, and by the unconformable deposit of Ordovician sediments, which are not affected. The telescoping of metamorphic isograds during DC2 and the geometry of detachment faults associated with this phase suggest extensional tectonics as the driving mechanism for the early exhumation of the Cadomian suture zone in Mina Afortunada Massif. The superimposition of Variscan folds and shear zones onto the Cadomian structures contributed to the subsequent exhumation of the Cadomian suture zone. The analysis and reconstruction of Cadomian and Variscan structures, plus the geochronological data, allow us to correlate the Cuartel Ophiolite with the Mérida Ophiolite, being two pieces of the same, yet dismembered, Cadomian suture zone. The number of Cadomian suture zones in Gondwana does not coincide with that of Cadomian suture zone exposures. Reworked orogens such as the Cadomian could be subjected to duplication of their suture zones. Assessments regarding the Cadomian paleogeography should consider the multiplier effect of the structural overprints after ophiolite accretion.

Advanced exploration of rare metal mineralization through integrated remote sensing and geophysical analysis of structurally-controlled hydrothermal alterations

Fusing multi-source (remote sensing and geophysical) data and diverse approaches validation in targeting hydrothermal alteration and structural anomalies enhances the potential for accurately detecting and characterizing mineralization zones. Sentinel 2 data and ASTER were processed for lithological and hydrothermal alteration mapping in the rare metal-rich Umm Naggat area (Egypt). Different image processing techniques were implemented, including false color composites, minimum noise fraction, band rationing, band math, mineral indices, relative absorption band depth, and constrained energy minimization. The rare metal-bearing Umm Naggat younger granite (NYG) pluton was lithologically discriminated and intra-differentiated to mafic-rich biotite granites, mafic-poor alkali feldspar granites, and albitized granites. Extensive hydrothermal alterations, such as albitization, ferrugination, propylitization, argillization, and phyllitization, overprint the NYG pluton. Normalized standard deviation, automatic lineament extractions, and trend analysis highlighted the key structural directions (NW, NNW, NNE, and NE) and distinguished the NYG pluton as a moderate to high structural density zone. The high structural density and intensive alteration zones are spatially associated and more localized within the NYG pluton than the surrounding rocks. Spatial overlay analysis confirmed that the hydrothermal alterations and fluid circulation systems are structurally-controlled. Furthermore, the hydrothermal alteration mapping and structural analysis outcomes were verified by combining fieldwork, slab polishing, petrographic investigations, and mineral chemistry through semi-quantitative scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) and quantitative electron probe microanalysis (EPMA) analysis. As a result, the hydrothermal genesis of rare metal-bearing minerals (Nb-rutile, Nb-ilmenite, and columbite) close to or incorporated within alteration minerals (chlorite, muscovite, and hematite) is confirmed from the alteration zones (propylitic, phyllic, and ferruginated). In addition, biotite muscovitization and chloritization significantly contribute to the secondary rare metal enrichment. The current study emphasizes the extensive distribution of secondary rare metal-bearing minerals within the entire NYG pluton (not only limited to the northern albitized granite as depicted by previous studies), which might shed light on these hydrothermally-altered younger granites as a new potential source for Nb and Ta in Egypt.

The potential of solid waste as a viable replacement for quartz sand in the ultra-high performance concrete: a comprehensive review

ABSTRACT Ultra-high performance concrete (UHPC) is renowned for its dense structure and exceptional mechanical properties, including durability. However, its widespread adoption is hindered by the high costs of essential fine aggregates like quartz sand and the associated environmental impact. Additionally, using industrial solid waste raises pollution concerns, contradicting global sustainability goals. Numerous studies have shown that it is feasible to produce eco-friendly UHPC with excellent performance by solid waste. This comprehensive review thoroughly investigates the workability, mechanical properties (including compressive strength, flexural strength and tensile strength), microstructure (encompassing pore structure and interfacial transition zone) and durability of UHPC incorporating solid waste in its production. The paper emphasizes the critical influence of factors, such as the solid waste substitution rate and the physical and chemical properties of solid waste. The paper also outlines the current application of UHPC with solid waste in pavement engineering and highlights the urgent need to address challenges such as high production costs, the lack of design standards and construction technique deficiencies, thereby emphasising the urgency surrounding the design and advancement of solid waste-incorporated UHPC in pavement engineering as it can reduce the environmental impact of traditional UHPC and improve the efficient use of solid waste.

Machine learning techniques for predicting the peak response of reinforced concrete beam subjected to impact loading

To meet the growing need for resilient structures in seismic and high-impact zones, accurate prediction of the response of reinforced concrete (RC) beams under impact loads is essential. Traditional methods, such as experimental testing and high fidelity finite element models, are often time consuming and resource intensive. To address these challenges, this study investigates various ensemble and non-ensemble machine learning techniques—including support vector machine, gaussian process regression (GPR), k-nearest neighbor (KNN), gene expression programming, random forest, decision tree, boosted tree, adaptive boosting tree, gradient boosting algorithm, stochastic gradient descent, and artificial neural network—for predicting the peak response of RC beams under impact loads. A set of 145 experimental data points from 12 different sources is used to train and evaluate these machine learning models. Key parameters in the data include beam width and depth, span, reinforcement ratios, concrete strength, steel yield strength, deflection, and impact characteristics. Except for KNN, all models showed satisfactory generalization capabilities with R2 values over 0.8. Statistical errors such as RMSE, a-10 index, MAE, and a-20 index are within acceptable limits. The GPR model is the most effective with R2 value of 0.95. Moreover, Shapely analysis identified beam depth, impact velocity, and beam breadth as critical factors. Overall, this study demonstrates the efficacy of machine learning in accurately predicting the behavior of RC structures under impact loads, providing valuable tools for civil engineers in design and analysis.

Fault zone architecture and hydraulic properties characterization using earth tide analysis

Fault zone architecture and hydraulic properties, which determine subsurface fluid flow and storage, have received long-term research attention from hydrogeologists. Current field experimental techniques and numerical simulation methods are limited by the scale and complexity of the investigations and are inadequate for deep subsurface fault zones. Estimating the internal rock properties and structures of fracture zones requires a combination of methods from many different fields. In recent years, groundwater tidal response methods have been widely used to characterize subsurface hydrogeomechanical properties because of their advantages of being in situ and low cost. In this study, tidal analysis was employed for a well within the Blue Ridge Fault Zone, and we integrated the fracture zone properties revealed by a single well. Well W-03 revealed an aquifer with an overall permeability of ∼ 10–14 m2 and hydraulic diffusivity of 0.24 m2⋅s−1. The fault damage zone had a permeability of 10–14 ∼ 10–13 m2 while the host rock had a permeability of 10–16 ∼ 10–14 m2. In addition, we found that the heterogeneity of specific storage affects the assessment of poroelasticity parameters, we offer a method to estimate these parameters without relying on specific storage, yielding porosity estimates ranging from 0.05 to 0.06, aligning with field test results. Furthermore, the estimated dip and strike of the fault zone were also consistent with the outcrop and borehole observations.

New insight into the velocity and anisotropy structures of the subduction zone in northern Sumatra

In this study, we conducted seismic tomographic inversions to investigate the velocity and anisotropy structures of northern Sumatra, using 9774 P-wave and 8405 S-wave arrivals from regional earthquakes. Isotropic P-wave velocity, isotropic S-wave velocity, P-wave azimuthal anisotropy, and P-wave radial anisotropy models were generated using eikonal equation-based traveltime tomography methods. The study identified low-velocity zones beneath the Toba and Sinabung volcanoes, potentially indicating the presence of magma reservoirs. Furthermore, low-velocity anomalies above the subduction slab were detected, which are likely caused by the dehydration of the slab and interpreted as channels of upwelling flow. The tomographic results revealed a trench-parallel high-velocity belt in the uppermost mantle, representing the subducting slab of the India-Australian plate. The trench-parallel fast velocity directions in the slab suggested that the subducted oceanic slab retains its frozen-in anisotropy formed at the mid-ocean ridge, or that the anisotropy is induced by the lattice-preferred orientation of the B-type olivine. Negative radial anisotropy in the mantle wedge was observed, reflecting hot upwelling flows and transitions of olivine fabrics in the presence of water due to slab dehydration. The results also indicated a multilevel magma plumbing system beneath the Toba Caldera. In summary, the results of this study provide new insights into the structure and dynamic processes of the northern Sumatra subduction zone.

Advancing instantaneous detonation prediction of condensed energetic materials based on high-order compressible multiphase fluid dynamics

The instantaneous detonation model (IDM) is widely used in simulating underwater explosions due to its efficiency and ability to ignore the detonation reaction process. In this study, we propose a new IDM to predict the fluid structure in the detonation zone of an RS211 explosive charge. This model is based on high-order solutions provided by the detonation shock dynamics model, where the spatial term is discretized using fifth-order WENO reconstruction in characteristic space and Lax–Friedrichs’s splitting and the temporal terms are discretized using a third-order TVD Runge–Kutta scheme. The interface motion is captured using the level-set method combined with MGFM, and a programmed burn model is provided to describe the generation and propagation of the detonation wave. The self-similarity of detonation wave propagation is validated, and the quantitative calculation formula of the instantaneous detonation model is obtained by averaging or curve fitting the dimensionless results. Consequently, the IDM of the RS211 charge is established using high-order polynomial approximations of the Taylor rarefaction zone and a constant static zone for 1D planar, cylindrical, and spherical RS211 charges. The application of the IDM involves direct mapping from the radial direction to the spatial structured grid for 1D planar, 2D cylindrical, and 3D spherical charges. Numerical results demonstrate that the IDM proposed in this paper shows good accuracy and high computational efficiency.

Evolution of Power‐Law Particle‐Size Distributions in Dense Grain‐Flow Experiments

AbstractUnderstanding particle fragmentation and its resulting particle‐size distribution is essential for comprehending shear zone formation, structure, and frictional behavior in faults and landslides, particularly at high normal stresses. 3‐D fractal dimension (D3) is used as a measure of particle‐size distribution, and for the potential self‐similarity physics. Previous research suggests D3 – 2.58 based on the “constrained comminution” model, or D3 = 3.00 considering large shear displacement. However, field data from rock avalanches reveal scattered D3 that deviate from these predictions, possibly due to the neglection of the underlying fragmented physics, such as the particle‐size‐dependent fragmentation probability. Herein, we conducted rotary shear experiments to investigate the evolution of D3 under varying normal stresses, velocities, and mineral compositions. Experimental results demonstrate that D3 monotonically increases with shear displacement and converges to an ultimate value, significantly influenced by mineral composition but less affected by shear velocity and confining stress within the experimental conditions. A modified large‐strain model that considered size‐dependent grain‐breakage probability was proposed, which may explain the observed divergence of D3 from previous predictions. This model highlights the complex mechanisms involved in particle breakage within dense grain‐flows, resulting in the high but scattered D3 observed in natural shear zones. Furthermore, we recognize that additional mechanisms, such as abrasion and grinding, can contribute to the particle size reduction and influence the ultimate fractal dimension. This study provides valuable insights into the dynamics of particle fragmentation in shear zones and has implications for understanding various geological processes.

Exploration breakthrough and factors for enrichment and high-yield of hydrocarbons in ultra-deep clastic rocks in Linhe Depression, Hetao Basin, NW China

Based on drilling and logging data, as well as geological experiments, the geological characteristics and factors controlling high-yield and enrichment of hydrocarbons in ultra-deep clastic rocks in the Linhe Depression, Hetao Basin, are studied. The results are obtained in four aspects. First, the inland saline lacustrine high-quality source rocks developed in the Paleogene in the Linhe Depression have the characteristics of early maturity, early expulsion, high hydrocarbon yield, and continuous and efficient hydrocarbon generation, providing an important resource basis for the formation of ultra-high pressure and high-yield reservoirs. Second, the weak compaction, early charging, and weak cementation for pore-preserving, together with the ultra-high pressure for pore-preserving and fracture expansion to improve the permeability, leads to the development of high-quality reservoirs with medium porosity (greater than 15%) and medium permeability (up to 226×10−3 μm2) in the ultra-deep strata (deeper than 6 500 m), which represents a greatly expanded space for oil and gas exploration. Third, the Linhe Formation adjacent to the trough exhibits a low net-to-gross (NTG) and good reservoir-caprock assemblage, and it is overlaid by very thick high-quality mudstone caprock, which are conducive to the continuous and efficient hydrocarbon generation and pressurization and the formation of ultra-high pressure oil and gas reservoirs. Fourth, the most favorable targets for ultra-deep exploration are the zones adjacent to the hydrocarbon generating center of the Paleogene Linhe Formation and with good tectonic setting and structural traps, mainly including the Xinglong faulted structural zone and the Nalinhu faulted buried-hill zone. The significant breakthrough of ultra-deep oil and gas exploration in the Linhe Depression reveals the good potential of ultra-deep clastic rocks in this area, and provides valuable reference for oil and gas exploration of ultra-deep clastic rocks in other areas.

Action of liquid tune mass dampers and base isolation in high rise buildings

In areas where earthquakes are common, high-rise structure seismic resistance is a major concern. The purpose of this research is to determine whether base isolation and liquid tuned mass dampers (LTMDs) can improve tall building seismic performance. A symmetrical G+8 story RCC structure in Zone V with medium grade soil is analyzed using ETABS software, Response Spectrum Analysis, and Equivalent Static Analysis to see how the structure behaves under different load combinations. For various structural configure rations, including basic models, models with water tanks, and models with base isolation, key factors such joint displacement, storey drift, base shear, and time period are evaluated. The results show that as compared to baseline models, models with damping and isolation systems exhibit much lower joint displacements, base shear forces, and story drift. In particular, base isolation models perform better in terms of reducing structural deformations and resisting lateral forces. Furthermore, shorter time periods and higher frequencies are routinely observed in base isolated models, suggesting enhanced dynamic response and energy dissipation capabilities. The paper also covers the flexibility and benefits of using LTMDs and base isolation to reduce seismic threats. Buildings can be successfully separated from ground motion by base isolation systems, and dynamic response can be countered by LTMDs using regulated liquid sloshing. The attraction of LTMDs in improving overall stability is increased by their adaptability in minimizing torsional and lateral vibrations. The study concludes by emphasizing how crucial it is to use cutting-edge structural retrofitting methods, including base isolation and LTMDs, to improve the seismic resistance of high-rise structures. In earthquake-prone areas, engineers and legislators may proactively protect tall buildings and guarantee a safer, more robust built environment by incorporating these technologies into construction standards and design procedures.

Surface Modification of Composite Coating for Marine Application: A Short Review

Corrosion is one of the phenomena that affects the deterioration of materials in offshore applications. Marine corrosion is particularly aggressive, due to the high salt content and low electrical resistivity of seawater. Corrosion cannot be stopped completely, but the reaction can be slowed down. Applying coating is an effective and widely used method to protect metal surfaces from corrosion. Coatings act as a barrier between the metal and its environment, preventing or slowing down the corrosive processes. Pursuant to ISO 12944, the most commonly used generics for coating systems in marine service are alkyd, acrylic, ethyl silicate, epoxy, vinyl ester, polyurethane, polyaspartic, and polysiloxane. The latest innovations in marine coatings still use a layer-by-layer coating method (e.g. primer coats, intermediate coats, and top coats) depending on thickness. Marine structures exposed to the atmospheric zones are usually coated with one or two coats of epoxy. A slightly more costly system of one coat of zinc-rich primer, one coat of epoxy, and one coat of aliphatic polyurethane may provide better performance. Coating systems for the atmospheric zones are frequently used in the intertidal and splash zones. Immersion zones of marine structures are commonly coated with one or two coats of 100% solid epoxy or three coats of solvent-borne epoxy. A single polymer as a generic coating have limitations. Adding fillers is a common method to improve the properties of polymers to become a composite. In marine coatings, fillers are still limited to glass flakes and powder. Poor dispersion and agglomeration might reduce the effectiveness of fillers in the matrix, which decreases the adhesion properties. The fillers must be surface modification before the application. This review provides a comprehensive and critical review of the current research status of composite coatings that serve as candidates to be used in marine coating.