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14 pages, 7293 KiB  
Article
The Genetic Mechanism and Geological Significance of Calcite in Buried-Hill Karstic Reservoirs: A Case Study of the Lower Paleozoic Carbonate Reservoirs in the Bohai Sea
by Xiuzhang Song, Tongyao Zhang, Peng Hao, Yahao Huang, Yinjun He and Chunyan Zang
Minerals 2025, 15(5), 508; https://doi.org/10.3390/min15050508 - 11 May 2025
Viewed by 430
Abstract
Calcite in hydrocarbon reservoirs records abundant information about diagenetic fluids and environments. Understanding the formation mechanisms of calcite is crucial for predicting reservoir characteristics and hydrocarbon migration. This study identifies the types of authigenic calcite present in the Lower Paleozoic carbonate reservoirs of [...] Read more.
Calcite in hydrocarbon reservoirs records abundant information about diagenetic fluids and environments. Understanding the formation mechanisms of calcite is crucial for predicting reservoir characteristics and hydrocarbon migration. This study identifies the types of authigenic calcite present in the Lower Paleozoic carbonate reservoirs of the Bohai Bay Basin through petrographic analysis, cathodoluminescence, and other experimental methods. By integrating electron probe microanalysis, in situ isotopic analysis, and fluid inclusion studies, we further constrain the source of the diagenetic fluids responsible for the authigenic calcite. The results show that there are at least three types of authigenic calcite in the Lower Paleozoic carbonate reservoirs of the Bohai Sea. Calcite cemented in the syn-depositional-to-early-diagenetic stage displays very weak cathodoluminescence, with δ13C and δ18O and paleo-salinity distributions similar to those of micritic calcite. These features suggest that the calcite was formed during burial heating by sedimentary fluids. Calcite filling fractures shows heterogeneous cathodoluminescence intensity, ranging from weak to strong, indicating multiple stages of cementation. The broad elemental variation and multiple cementation events suggest that the diagenetic fluid sources were diverse. Isotopic data show that samples with carbon isotope values greater than −2.9‰ likely formed through water–rock interaction with fluids retained within the strata, whereas samples exhibiting more negative δ13C were formed from a mixed-source supply of strata and mantle-derived fluids. Calcite that fills karst collapse pores exhibits alternating bright and dark cathodoluminescence, strong negative δ18O shifts, and variability in trace elements such as Mn, Fe, and Co. These characteristics indicate a mixed origin of diagenetic fluids derived from both meteoric freshwater and carbonate-dissolving fluids. Full article
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30 pages, 16764 KiB  
Article
Design of a Device for Optimizing Burden Distribution in a Blast Furnace Hopper
by Gabriele Degrassi, Lucia Parussini, Marco Boscolo, Elio Padoano, Carlo Poloni, Nicola Petronelli and Vincenzo Dimastromatteo
Information 2025, 16(5), 337; https://doi.org/10.3390/info16050337 - 22 Apr 2025
Viewed by 421
Abstract
The coke and ore are stacked alternately in layers inside the blast furnace. The capability of the charging system to distribute them in the desired manner and with optimum strata thickness is crucial for the efficiency and high-performance operation of the blast furnace [...] Read more.
The coke and ore are stacked alternately in layers inside the blast furnace. The capability of the charging system to distribute them in the desired manner and with optimum strata thickness is crucial for the efficiency and high-performance operation of the blast furnace itself. The objective of this work is the optimization of the charging equipment of a specific blast furnace. This blast furnace consists of a hopper, a single bell and a deflector inserted in the hopper under the conveyor belt. The focus is the search for a deflector geometry capable of distributing the material as evenly as possible in the hopper in order to ensure the effective disposal of the material released in the blast furnace. This search was performed by coupling the discrete element method with a multi-strategy and self-adapting optimization algorithm. The numerical results were qualitatively validated with a laboratory-scale model. Low cost and the simplicity of operation and maintenance are the strengths of the proposed charging system. Moreover, the methodological approach can be extended to other applications and contexts, such as chemical, pharmaceutical and food processing industries. This is especially true when complex material release conditions necessitate achieving bulk material distribution requirements in containers, silos, hoppers or similar components. Full article
(This article belongs to the Special Issue Optimization Algorithms and Their Applications)
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18 pages, 7392 KiB  
Article
Transferring Pressure Mechanism Across Gob-Side Roadway Goaf with Coal Pillar During Distant Face Mining: A Case Study
by Houqiang Yang, Changliang Han, Nong Zhang, Jiande Wang, Qingguang Chen, Jie Liu and Shenghan He
Appl. Sci. 2025, 15(8), 4274; https://doi.org/10.3390/app15084274 - 12 Apr 2025
Viewed by 320
Abstract
The gob-side roadway technique is extensively utilized in coal extraction due to its capacity to enhance coal resource recovery efficiency and mitigate mining sequence conflicts. Nevertheless, increasing mining depths lead to progressively intricate stress conditions, posing challenges for maintaining gob-adjacent roadway surrounding rock [...] Read more.
The gob-side roadway technique is extensively utilized in coal extraction due to its capacity to enhance coal resource recovery efficiency and mitigate mining sequence conflicts. Nevertheless, increasing mining depths lead to progressively intricate stress conditions, posing challenges for maintaining gob-adjacent roadway surrounding rock stability. Taking the belt haulage roadway 1513 (BHR 1513) at Xinyi Coal Mine as an engineering case, this research investigates the application of narrow-pillar gob-side roadway construction under remote working face mining conditions. By integrating field observations, analytical modeling, and computational simulations, the cross-goaf pressure transfer phenomenon and its formation mechanism in narrow-pillar roadways under distant mining operations are systematically examined. Key findings reveal that during the alternating extraction of wide and narrow working faces, the caving angle terminates roof collapse within the narrow working face goaf at the second key stratum (KS2). The subsequent mining of the adjacent wide working face induces stress accumulation in the overlying “T”-shaped strata zone, triggering the instability of the inter-working face island pillar. This pillar failure merges the two goafs into an expanded void, initiating sequential fracture, collapse, and rotational displacement across all overlying key strata (KS). Consequently, previously intact KS above the narrow working face goaf undergo fracturing and rotation, amplifying lateral main roof block subsidence toward the goaf. This kinematic process generates substantial deformation in the narrow-pillar gob-side roadway. Full article
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33 pages, 44898 KiB  
Article
The Supra-Salt Sedimentary Sequence of the North Caspian Depression: Stratigraphy and Sedimentary History
by Aitbek Akhmetzhanov, Saule Uvakova, Kenzhebek Ibrashev, Gauhar Akhmetzhanova and Vyacheslav Zhemchuzhnikov
Geosciences 2025, 15(4), 143; https://doi.org/10.3390/geosciences15040143 - 9 Apr 2025
Viewed by 590
Abstract
The North Caspian Basin, known for its oil and gas potential, was formed because of the evolution of the ancient Tethys Ocean and is also a result of the collision of the East European, Kazakhstania, and Siberian paleocontinents. At the beginning of the [...] Read more.
The North Caspian Basin, known for its oil and gas potential, was formed because of the evolution of the ancient Tethys Ocean and is also a result of the collision of the East European, Kazakhstania, and Siberian paleocontinents. At the beginning of the Mesozoic Era, it was a part of the northern continental margin of the Neo-Tethys, which formed Eurasia. In the Late Triassic and Early Jurassic, a major restructuring of the North Caspian sedimentary basin occurred, characterized by angular unconformity and the erosion of underlying sediments in the coastal zones of the basin. The sedimentary succession of the depression accumulating in the Mesozoic Era consisted of alternating siliciclastic and carbonate rocks. It began to form due to the destruction of the uplifts formed north and west of the East European craton and Urals, which resulted in coastal clastic material in the Triassic and Jurassic, but by the end of the Jurassic and Cretaceous, when all uplifts existing in the north of Tethys were leveled, it was mostly marine environments that contributed to the accumulation of siliciclastic and carbonate strata. The appearance of a large amount of sedimentary material towards the center of the depression, causing stress, as well as the deflection of the basement, contributed to fault tectonics and the resumption and manifestation of salt tectonics. As a result of the continuous diapirism of salt bodies during the Late Mesozoic, mini basins were formed, in which different sedimentogenesis was manifested. These processes contributed to the redistribution of hydrocarbons from the underlying pre-salt formations to the intermediate depth interval post-salt succession with Permian–Triassic and also near-surface Jurassic–Cretaceous formations. Full article
(This article belongs to the Section Sedimentology, Stratigraphy and Palaeontology)
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23 pages, 2347 KiB  
Review
The Cause–Effect Model of Master Sex Determination Gene Acquisition and the Evolution of Sex Chromosomes
by Zhanjiang Liu and Dongya Gao
Int. J. Mol. Sci. 2025, 26(7), 3282; https://doi.org/10.3390/ijms26073282 - 1 Apr 2025
Viewed by 946
Abstract
The canonical model of vertebrate sex chromosome evolution predicts a one-way trend toward degradation. However, most sex chromosomes in lower vertebrates are homomorphic. Recent progress in studies of sex determination has resulted in the discovery of more than 30 master sex determination (MSD) [...] Read more.
The canonical model of vertebrate sex chromosome evolution predicts a one-way trend toward degradation. However, most sex chromosomes in lower vertebrates are homomorphic. Recent progress in studies of sex determination has resulted in the discovery of more than 30 master sex determination (MSD) genes, most of which are from teleost fish. An analysis of MSD gene acquisition, recombination suppression, and sex chromosome-specific sequences revealed correlations in the modes of MSD gene acquisition and the evolution of sex chromosomes. Sex chromosomes remain homomorphic with MSD genes acquired by simple mutations, gene duplications, allelic variations, or neofunctionalization; in contrast, they become heteromorphic with MSD genes acquired by chromosomal inversion, fusion, and fission. There is no recombination suppression with sex chromosomes carrying MSD genes gained through simple mutations. In contrast, there is extensive recombination suppression with sex chromosomes carrying MSD genes gained through chromosome inversion. There is limited recombination suppression with sex chromosomes carrying MSD genes gained through transposition or translocation. We propose a cause–effect model that predicts sex chromosome evolution as a consequence of the acquisition modes of MSD genes, which explains the evolution of sex chromosomes in various vertebrates. A key factor determining the trend of sex chromosome evolution is whether non-homologous regions are created during the acquisition of MSD genes. Chromosome inversion creates inversely homologous but directly non-homologous sequences, which lead to recombination suppression but retain recombination potential. Over time, recurrent recombination in the inverted regions leads to the formation of strata and may cause the degradation of sex chromosomes. Depending on the nature of deletions in the inverted regions, sex chromosomes may evolve with dosage compensation, or the selective retention of haplo-insufficient genes may be used as an alternative strategy. Full article
(This article belongs to the Section Molecular Genetics and Genomics)
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14 pages, 5642 KiB  
Article
Investigating and Evaluating Novel Fly Ash-Based Proppant Compressive Strength Under Various Environmental Conditions
by Raz Haydar and Sherif Fakher
Materials 2025, 18(2), 399; https://doi.org/10.3390/ma18020399 - 16 Jan 2025
Cited by 3 | Viewed by 986
Abstract
As hydraulic fracturing becomes increasingly prevalent in the oil and gas industry, there is a growing need to develop more cost-effective and sustainable technologies, particularly concerning the materials used. Proppants play a vital role in hydraulic fracturing by ensuring that fractures remain conductive [...] Read more.
As hydraulic fracturing becomes increasingly prevalent in the oil and gas industry, there is a growing need to develop more cost-effective and sustainable technologies, particularly concerning the materials used. Proppants play a vital role in hydraulic fracturing by ensuring that fractures remain conductive and can withstand the pressure exerted by the surrounding strata. One key parameter for evaluating proppants is their compressive strength, especially under harsh environmental conditions. High-strength proppants, such as those made from ceramics or bauxite, are typically expensive due to the materials and complex manufacturing processes involved. In contrast, fly ash, a byproduct of coal-fired power plants, offers a more affordable and environmentally sustainable alternative for proppant production. This study focuses on the development and evaluation of a fly ash-based proppant, exposed to harsh conditions including high temperature and pressure, as well as acidic, alkaline, saline, and crude oil environments. The fly ash was activated using an alkaline solution, which served as a chemical binder for the proppant. After exposure to these conditions, the compressive strength of the fly ash-based proppants was compared to control samples. The results showed that the proppants’ compressive strength was largely unaffected by the harsh environments, particularly for the B20W25 mix design. However, while the fly ash-based proppants performed well under stress, their compressive strength was still lower than that of conventional proppants used in the industry. The B20W25 sample demonstrated a compressive strength of 1181.19 psi (8.1 MPa), which, although resilient, remains below industry standards. Full article
(This article belongs to the Topic Advances in Sustainable Materials and Products)
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26 pages, 26313 KiB  
Article
Characteristics and Paleoenvironment of Stromatolites in the Southern North China Craton and Their Implications for Mesoproterozoic Gas Exploration
by Ruize Yuan, Qiang Yu, Tao Tian, Qike Yang, Zhanli Ren, Rongxi Li, Baojiang Wang, Wei Chang, Lijuan He and Tianzi Wang
Processes 2025, 13(1), 129; https://doi.org/10.3390/pr13010129 - 6 Jan 2025
Cited by 1 | Viewed by 1261
Abstract
Stromatolites, distinctive fossil records within Precambrian strata, are essential for investigating the depositional environments of early Earth and the geological settings conducive to hydrocarbon formation. The Luonan area is located in Shaanxi Province, China, where a large number of stromatolites have been discovered [...] Read more.
Stromatolites, distinctive fossil records within Precambrian strata, are essential for investigating the depositional environments of early Earth and the geological settings conducive to hydrocarbon formation. The Luonan area is located in Shaanxi Province, China, where a large number of stromatolites have been discovered within the Mesoproterozoic Erathem, providing new perspectives on paleoenvironment and reservoir spaces. This study analyzes the morphology of stromatolites, associated microorganisms, mineralogy, and cathodoluminescence from the carbonate rocks of the Jixian System. Carbon and oxygen isotope analyses help reconstruct paleosalinity and climate, enhancing understanding of their petroleum geological significance. Combining carbon and oxygen isotope analysis with the fine observation and description of stromatolite can better reconstruct the paleoenvironmental features of the Mesoproterozoic Era. The results indicated a narrow range of carbon isotope values (δ13C: −5.81‰ to −2.43‰; mean: −4.03‰) and oxygen isotope values (δ18O: −9.06‰ to −5.64‰). The Longjiayuan Formation is characterized by high CaO and MgO content, with low SiO2 and minimal terrigenous input, in contrast with the Fengjiawan Formation, which exhibits elevated SiO2 and greater terrigenous material. The Luonan stromatolites display prominent rhythmic laminations, primarily composed of dolomite, indicating a potential for hydrocarbon source rocks. Stromatolite morphologies, including layered, columnar, and wavy forms, reflect varied depositional microfacies. The alternating bright and dark laminae, rich in CaO and CO2 but differing in Ca2+ and Mg2+ concentrations, signify seasonal growth cycles. These Mesoproterozoic stromatolites developed in a warm, humid, and stable climatic regime, within a marine anoxic-to-suboxic setting, typically in intertidal or supratidal zones with low hydrodynamic energy. In the southern margin of the North China Craton, stromatolites from the Mesoproterozoic Era are extensively developed and exhibit distinct characteristics. Due to the biogenic alteration of stromatolites, the porosity of the rock increased. These stromatolites have altered the physical properties of the host rocks to some extent, suggesting the possibility of becoming effective hydrocarbon reservoirs. This has significant implications for deep oil and gas exploration, providing valuable guidance for future prospecting efforts. Full article
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21 pages, 8843 KiB  
Article
Organic Geochemical Characteristics and Hydrocarbon Significance of the Permian System Around the Bogda Mountain, Junggar Basin, Northwest China
by Jiaquan Zhou, Chao Li, Ziyi Song and Xinlei Zhang
Sustainability 2025, 17(1), 347; https://doi.org/10.3390/su17010347 - 5 Jan 2025
Cited by 3 | Viewed by 1245
Abstract
Shale oil and gas resources have become an alternative energy source and are crucial in the field of sustainable oil and gas exploration. In the Junggar Basin, the Permian is not only the most significant source rock, but also an important field in [...] Read more.
Shale oil and gas resources have become an alternative energy source and are crucial in the field of sustainable oil and gas exploration. In the Junggar Basin, the Permian is not only the most significant source rock, but also an important field in shale oil and gas exploration. However, there are significant differences in the effectiveness of source rocks in different layers. During the Permian, the Bogda region effectively recorded the transition from marine environments in the Early Permian to terrestrial environments in the Late Permian, providing a viable opportunity for studying the Permian source rock of the Junggar Basin. We conducted an analysis of the total organic carbon (TOC), Rock-Eval pyrolysis, vitrinite reflectance (Ro), and biomarker compounds of Permian source rocks around the Bogda Mountain. The results indicate that the Lower Permian strata were primarily deposited in a moderately reducing marine environment, with the main organic matter sourced from planktonic organisms. These strata are currently in a high to over-mature stage, evaluated as medium-quality source rocks, and may have already generated and expelled substantial quantities of oil and gas, making the Lower Permian hydrocarbon resources within the basin a noteworthy target for deep condensate oil and gas exploration in adjacent depressions. The Middle Permian Wulabo and Jingjingzigou formations were deposited in a moderately oxidizing marine–continental transitional environment with significant terrestrial organic input. The kerogen type is predominantly Type III, and these formations are presently in the mature to over-mature stage with low organic abundance and poor hydrocarbon generation potential. The Middle Permian Lucaogou Formation was deposited in a moderately reducing saline lacustrine environment, with algae and planktonic organisms as the primary sources of organic matter. The kerogen types are mainly Type I and II1, and it is currently within the oil-generation window. It is characterized by high organic abundance and evaluated as good to excellent source rocks, possessing substantial potential for shale oil exploration. The Upper Permian Wutonggou Formation was primarily deposited in a highly oxidizing continental environment with significant terrestrial input. The primary organic source comprises higher plants, resulting in Type III kerogen. These strata exhibit low organic abundance, are currently in the immature to mature stage, and are evaluated as poor source rocks with limited exploration potential. The information presented in this paper has important theoretical significance and practical value for oil and gas exploration and development in the Junggar Basin. Full article
(This article belongs to the Topic Recent Advances in Diagenesis and Reservoir 3D Modeling)
(This article belongs to the Section Sustainability in Geographic Science)
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12 pages, 632 KiB  
Article
Influence of an Alternative Diagnosis on the Diagnosis of Pulmonary Thromboembolism
by Rafael Suárez del Villar Carrero, Diego Martínez-Urbistondo, Miguel De la Serna Real de Asúa, Ángel Cano Mazarro, María Agud Fernández, Ana Rodríguez Cobo and Paula Villares Fernández
Healthcare 2024, 12(22), 2246; https://doi.org/10.3390/healthcare12222246 - 11 Nov 2024
Viewed by 1020
Abstract
Background: The diagnosis of pulmonary embolism (PE) is based on the application of a priori probability scales such as the Wells scale or PERC. However, the clinical heterogeneity of this pathology results in the absence of a target population to apply these algorithms. [...] Read more.
Background: The diagnosis of pulmonary embolism (PE) is based on the application of a priori probability scales such as the Wells scale or PERC. However, the clinical heterogeneity of this pathology results in the absence of a target population to apply these algorithms. The Wells score does consider the possibility of an alternative diagnosis, awarding an additional point if no other diagnosis is likely, yet the presence of objective alternative diagnoses can still complicate clinical assessment and lead to unnecessary testing or missed diagnoses. Objective: The aim of this study is to evaluate the discrimination capacity of clinical objective factors with a high negative predictive value for PE, compared to PERC in terms of reducing unnecessary testing across different risk strata of the Wells scale. Materials and Methods: This was a single-center retrospective cohort study, including patients who underwent chest CT angiography to rule out PE at a university hospital between 2008 and 2017, considering the presence of PE as the study outcome. The study collected demographic data, comorbidities, and clinical presentation data. The presence of objective criteria for pneumonia, heart failure, exacerbation of COPD, or the use of anticoagulation in non-oncological patients were considered a priori criteria with a high negative predictive value. Results: The analyses were performed on a cohort of 399 patients with an average age of 65 years and 53% females. A total of 139 patients were diagnosed with PE by CT angiography. The presence of factors with a high NPV showed a sensitivity of 100% in low-risk patients according to Wells, with sensitivity dropping below 50% in other populations. The association of these factors in the PERC plus criteria would allow a reduction of up to 34% in CT angiographies in patients with low risk according to the Wells scale. Conclusions: The combination of risk stratification of the Wells scale and PERC plus criteria allows an absolute reduction of 34.3% in the performance of CT angiographies in patients classified as low risk with a sensitivity and a negative predictive value of 100%. The preexistence of an alternative diagnosis does not allow ruling out PE in patients with intermediate or high risk according to the Wells scale. Full article
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13 pages, 6828 KiB  
Article
A Regional Paleoclimate Record of the Tropical Aeolian Sands during the Last Deglaciation in Hainan, China
by Fengnian Wang, Baosheng Li, Dongfeng Niu, Xiaoze Li, Yuejun Si, Peixian Shu, Zhiwen Li, Shuhuan Du, Qiwen Chen and Min Chen
Water 2024, 16(20), 2901; https://doi.org/10.3390/w16202901 - 12 Oct 2024
Viewed by 874
Abstract
The KLD segment of the Kenweiyuan section in Wenchang, Hainan, China is a set of aeolian sand deposits of the Last Deglaciation. The chemical element and heavy mineral analysis performed in this study reveals the chemical index of alteration (CIA) in the segment [...] Read more.
The KLD segment of the Kenweiyuan section in Wenchang, Hainan, China is a set of aeolian sand deposits of the Last Deglaciation. The chemical element and heavy mineral analysis performed in this study reveals the chemical index of alteration (CIA) in the segment to be as high as 93–95, with all the heavy minerals identified as stable and extremely stable making up 38–45% of the total. Furthermore, the zircon, tourmaline, and rutile content (ZTR index) of the segment is determined to range between 48–71. The (Al2O3 + TOFE)/SiO2 ratios display obvious fluctuations from old to new strata in the segment, with the low values corresponding to Heinrich event (H1), Dansgaard-Oeschager (D-O), and Younger Dryas (YD) and the high values corresponding to Bølling and Allerød. Our study suggests that these fluctuations are attributed to the alternation of the East Asian winter and summer monsoons. Hainan Island is also impacted by the surface ocean climate of the South China Sea, and characteristics of the KLD segment may be connected to the climate changes in the North Atlantic related to the winter monsoon season or westerlies. Furthermore, the segment presents a clear response to millennium-scale climate changes during the Last Deglaciation on Hainan Island. Based on the high CIA values in the KLD segment, and particularly due to the observed stable detrital minerals, the ratios can be linked to the overall tropical climate, indicating a relatively warm tropical climate environment in the Last Deglaciation in Hainan. The high CIA values also reveal the cause of aeolian sand formation under the tropical environmental conditions in the low latitude region of China in the Late Quaternary. Full article
(This article belongs to the Section Water and Climate Change)
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12 pages, 7032 KiB  
Article
Vertical Stratification of Butterfly Assemblages Persists in Highly Disturbed Forest Fragments of the Brazilian Atlantic Forest
by Denise B. Silva, André V. L. Freitas, Oscar F. Junior and Jessie P. Santos
Diversity 2024, 16(10), 608; https://doi.org/10.3390/d16100608 - 1 Oct 2024
Viewed by 1239
Abstract
Vertical stratification is a property of forest habitats related to the differential distribution of organisms according to the variation in the conditions, from the understory to the canopy. Here, we aimed to test whether butterfly assemblages from highly disturbed forests maintain the pattern [...] Read more.
Vertical stratification is a property of forest habitats related to the differential distribution of organisms according to the variation in the conditions, from the understory to the canopy. Here, we aimed to test whether butterfly assemblages from highly disturbed forests maintain the pattern of vertical stratification. We hypothesized that degraded forests would not exhibit vertical stratification due to the low variation in the microhabitat conditions along the vertical gradient, resulting from the canopy openness. To test this, we sampled fruit-feeding butterflies with bait traps, alternately disposed between the understory and canopy of three secondary forest fragments in a very fragmented Atlantic Forest landscape, for one year. We found that the vertical strata differed in terms of species composition, with a high contribution by the nestedness component on the beta diversity spatial variation. The understory assemblages had a higher abundance and were more diverse than the upper stratum. We demonstrated that vertical stratification is maintained even in disturbed forests; however, this does not necessarily provide support for a good quality and functioning ecosystem in these habitats. The butterfly assemblages recorded here are a subset of the species pool that inhabits conserved remnants. Thus, even being represented by species commonly found in disturbed habitats, the dynamic of vertical stratification of assemblages remains. Full article
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44 pages, 21329 KiB  
Review
The Chemistry and Mineralogy (CheMin) X-ray Diffractometer on the MSL Curiosity Rover: A Decade of Mineralogy from Gale Crater, Mars
by David Blake, Valerie Tu, Thomas Bristow, Elizabeth Rampe, David Vaniman, Steve Chipera, Philippe Sarrazin, Richard Morris, Shaunna Morrison, Albert Yen, Robert Downs, Robert Hazen, Allan Treiman, Douglas Ming, Gordon Downs, Cherie Achilles, Nicholas Castle, Tanya Peretyazhko, David De Marais, Patricia Craig, Barbara Lafuente, Benjamin Tutolo, Elisabeth Hausrath, Sarah Simpson, Richard Walroth, Michael Thorpe, Johannes Meusburger, Aditi Pandey, Marc Gailhanou, Przemyslaw Dera, Jeffrey Berger, Lucy Thompson, Ralf Gellert, Amy McAdam, Catherine O’Connell-Cooper, Brad Sutter, John Michael Morookian, Abigail Fraeman, John Grotzinger, Kirsten Siebach, Soren Madsen and Ashwin Vasavadaadd Show full author list remove Hide full author list
Minerals 2024, 14(6), 568; https://doi.org/10.3390/min14060568 - 29 May 2024
Cited by 9 | Viewed by 4390
Abstract
For more than a decade, the CheMin X-ray diffraction instrument on the Mars Science Laboratory rover, Curiosity, has been returning definitive and quantitative mineralogical and mineral–chemistry data from ~3.5-billion-year-old (Ga) sediments in Gale crater, Mars. To date, 40 drilled rock samples and [...] Read more.
For more than a decade, the CheMin X-ray diffraction instrument on the Mars Science Laboratory rover, Curiosity, has been returning definitive and quantitative mineralogical and mineral–chemistry data from ~3.5-billion-year-old (Ga) sediments in Gale crater, Mars. To date, 40 drilled rock samples and three scooped soil samples have been analyzed during the rover’s 30+ km transit. These samples document the mineralogy of over 800 m of flat-lying fluvial, lacustrine, and aeolian sedimentary rocks that comprise the lower strata of the central mound of Gale crater (Aeolis Mons, informally known as Mt. Sharp) and the surrounding plains (Aeolis Palus, informally known as the Bradbury Rise). The principal mineralogy of the sedimentary rocks is of basaltic composition, with evidence of post-depositional diagenetic overprinting. The rocks in many cases preserve much of their primary mineralogy and sedimentary features, suggesting that they were never strongly heated or deformed. Using aeolian soil composition as a proxy for the composition of the deposited and lithified sediment, it appears that, in many cases, the diagenetic changes observed are principally isochemical. Exceptions to this trend include secondary nodules, calcium sulfate veining, and rare Si-rich alteration halos. A surprising and yet poorly understood observation is that nearly all of the ~3.5 Ga sedimentary rocks analyzed to date contain 15–70 wt.% of X-ray amorphous material. Overall, this >800 m section of sedimentary rock explored in lower Mt. Sharp documents a perennial shallow lake environment grading upward into alternating lacustrine/fluvial and aeolian environments, many of which would have been habitable to microbial life. Full article
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18 pages, 2434 KiB  
Article
The Gaseous Hydrogen Transport Capacity in Nanopores Coupling Bulk Flow Mechanisms and Surface Diffusion: Integration of Profession and Innovation
by Yanglu Wan, Wei Lu, Zhouman Huang, Rucang Qian and Zheng Sun
Processes 2024, 12(5), 972; https://doi.org/10.3390/pr12050972 - 10 May 2024
Viewed by 1428
Abstract
Due to its unique chemical structure, hydrogen energy inherently has a high calorific value without reinforcing global warming, so it is expected to be a promising alternative energy source in the future. In this work, we focus on nanoconfined hydrogen flow performance, a [...] Read more.
Due to its unique chemical structure, hydrogen energy inherently has a high calorific value without reinforcing global warming, so it is expected to be a promising alternative energy source in the future. In this work, we focus on nanoconfined hydrogen flow performance, a critical issue in terms of geological hydrogen storage. For nanopores where the pore scale is comparable to hydrogen’s molecular size, the impact on hydrogen molecules exerted by the pore surface cannot be neglected, leading to the molecules near the surface gaining mobility and slipping on the surface. Furthermore, hydrogen adsorption takes place in the nanopores, and the way the adsorption molecules move is completely different from the bulk molecules. Hence, the frequently applied Navier–Stokes equation, based on the no-slip boundary condition and overlooking the contribution of the adsorption molecules, fails to precisely predict the hydrogen flow capacity in nanopores. In this paper, hydrogen molecules are classified as bulk molecules and adsorption molecules, and then models for the bulk hydrogen and the adsorption hydrogen are developed separately. In detail, the bulk hydrogen model considers the slip boundary and rarefaction effect characterized by the Knudsen number, while the flow of the adsorption hydrogen is driven by a chemical potential gradient, which is a function of pressure and the essential adsorption capacity. Subsequently, a general model for the hydrogen flow in nanopores is established through weight superposition of the bulk hydrogen flow as well as the adsorption hydrogen, and the key weight coefficients are determined according to the volume proportion of the identified area. The results indicate that (a) the surface diffusion of the adsorption molecules dominates the hydrogen flow capacity inside nanopores with a pore size of less than 5 nm; (b) improving the pressure benefits the bulk hydrogen flow and plays a detrimental role in reducing surface diffusion at a relatively large pressure range; (c) the nanoconfined hydrogen flow conductance with a strong adsorption capacity (PL = 2 MPa) could reach a value ten times greater than that with a weak adsorption capacity (PL = 10 MPa). This research provides a profound framework for exploring hydrogen flow behavior in ultra-tight strata related to adsorption phenomena. Full article
(This article belongs to the Section Energy Systems)
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32 pages, 7422 KiB  
Article
Numerical Investigation of Large-Diameter Bored Piles under High-Strain Dynamic Testing: A Case Study in New Alamein City
by Tarek N. Salem, Ahmed S. El-Saei, Katarína Krajníková, Dušan Katunský and Rana Hassan
Buildings 2024, 14(4), 1133; https://doi.org/10.3390/buildings14041133 - 17 Apr 2024
Viewed by 2385
Abstract
Large-diameter bored piles can safely transmit loads from structures by skin friction to the surrounding soil strata and end bearing at the bedrock layer, thereby providing a high compressive capacity. High-Strain Dynamic Testing (HSDT) provides a unique alternative technique to traditional Static Load [...] Read more.
Large-diameter bored piles can safely transmit loads from structures by skin friction to the surrounding soil strata and end bearing at the bedrock layer, thereby providing a high compressive capacity. High-Strain Dynamic Testing (HSDT) provides a unique alternative technique to traditional Static Load Testing (SLT) for determining the static compressive resistance of the bored piles, considering its quicker performance and significant cost reductions. This article’s main objective is to numerically explore the performance of large-diameter bored piles during the HSDT and to understand their dynamic behavior under an axial compressive impact force. This research is based on testing pile foundations for reinforced concrete mixed-use towers in the coastal zone of New Alamein City, Egypt. The tested pile is a 1.20 m diameter bored pile. Numerical modeling is performed to simulate both the HSDT and the SLT for two piles at the same site. Non-linear axisymmetric finite element modeling is employed to validate both test records and develop some sort of matching between the two tests. As lumped models, the developed numerical models use the signal-matching process, which is conducted by varying and adopting the strength parameters and deformation characteristics of the ground or soil deposit and the soil–pile interface. The predicted load-displacement curves, developed from analyzing dynamic records employing the Modified Unloading Point (MUP) method, are consistent with the field records. The verified non-linear models are utilized to accomplish a comparative parametric analysis to better understand the drop-mass system aspects. The analysis results emphasize the significance of employing adequate impact energy (i.e., dropping height and mass) to move the pile top to a sufficient extent to mobilize its full resistance. However, a longer impact duration, i.e., larger mass, is more effective for achieving a deeper high-strain wave. The impact load should be developed by a larger drop mass with a lower drop height, not a smaller drop mass with a higher drop height. The results also indicate that, for relatively longer piles, the skin friction of the upper layers surrounding the pile shaft is fully mobilized, whereas the skin resistance of the lower layers is not fully mobilized, regarding the stress wave phenomenon effect. Finally, this study’s findings can be employed to develop guidelines and design procedures for the HSDT to be effectively performed on bored piles. Full article
(This article belongs to the Section Building Energy, Physics, Environment, and Systems)
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20 pages, 10161 KiB  
Article
Utilizing Crushed Limestone as a Sustainable Alternative in Shotcrete Applications
by Elamin Mutaz, Muawia Dafalla, Ahmed M. Al-Mahbashi and Mehdi Serati
Materials 2024, 17(7), 1486; https://doi.org/10.3390/ma17071486 - 25 Mar 2024
Cited by 2 | Viewed by 1593
Abstract
Solving the challenges facing the mining industry is crucial for shaping the global attitude towards clean energy technologies associated with critical minerals extracted from depth. One of these challenges is the well-known explosion-like fractures (rockbursts) or spalling failures associated with the initiation of [...] Read more.
Solving the challenges facing the mining industry is crucial for shaping the global attitude towards clean energy technologies associated with critical minerals extracted from depth. One of these challenges is the well-known explosion-like fractures (rockbursts) or spalling failures associated with the initiation of internal cracks. To prevent such catastrophic failure, shotcrete, as a cement grout, is widely used in tunnel support applications. In areas where the tunnels are constructed within the limestone strata using tunnel boring machines (TBM), drilling, and/or blasting, millions of cubic meters of crushed limestone (CL) in powder form are extracted and landfilled as waste. Given the fact that natural sand consumption as a raw material in the construction industry exceeds previous records, recycling of such excavation material is now becoming increasingly needed. From this perspective, this study aims to utilize crushed limestone as a potentially sustainable alternative to natural sand in shotcrete applications in deep tunnels. Accordingly, several strength characterization and crack initiation determinations through various stress–strain-based models were carried out on cylindrical samples containing different proportions of crushed limestone. By increasing the crushed limestone content in the shotcrete mix, the crack initiation stress (as a measure of the in situ spalling strength) increased as well. The results suggest that the crushed limestone has good potential to replace the natural sand in the shotcrete mixture used in tunnel support applications. Full article
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